Molecular weight of deoxyribonucleic acid synthesized during initiation of chromosome replication in Escherichia coli. Alkaline sucrose gradients were used to study the molecular weight of deoxyribonucleic acid (DNA) synthesized during the initiation of chromosome replication in Escherichia coli 15 TAU-bar. The experiments were conducted to determine whether newly synthesized, replication origin DNA is attached to higher-molecular-weight parental DNA. Little of the DNA synthesized after readdition of required amino acids to cells previously deprived of the amino acids was present in DNA with a molecular weight comparable to that of the parental DNA. The newly synthesized, low-molecular-weight DNA rapidly appeared in higher-molecular-weight material, but there was an upper limit to the size of this intermediate-molecular-weight DNA. This limit was not observed when exponentially growing cells converted newly synthesized DNA to higher-molecular-weight material. The size of the intermediate-molecular-weight DNA was related to the age of the replication forks, and the size increased as the replication forks moved further from the replication origin. The results indicate that the newly synthesized replication origin DNA is not attached to parental DNA, but it is rapidly attached to the growing strands that extend from the replication fork to the replication origin, or to the other replication fork if replication is bidirectional. Experiments are reported which demonstrate that the DNA investigated was from the vicinity of the replication origin and was not plasmid DNA or DNA from random positions on the chromosome.


Studies in the viability of Mycobacterium leprae in human liver and bone marrow using thymectomized mouse foot pad technic.


The identification of leprosy among epithelioid cell granulomas of the skin.


Repression of enzymes of arginine biosynthesis by L-canavanine in arginyl-transfer ribonucleic acid synthetase mutants of Escherichia coli. We show that the arginine analogue, l-canavanine, repressed the accumulation of translatable messenger ribonucleic acid (RNA) for three arginine biosynthetic enzymes in Escherichia coli. The method used to determine the level of translatable messenger RNA depended upon measurement of a burst of enzyme synthesis as described previously. E. coli strains with defective arginyltransfer ribonucleic acid (tRNA) synthetase (argS mutants) were insensitive to canavanine repression. When deprived of leucine, a leu argS strain regained normal sensitivity to canavanine repression. The level of in vivo canavanyl-tRNA(arg) was determined for a normal strain and an argS mutant. After 20 min of growth with canavanine only 9% of tRNA(arg) from the argS strain was protected from periodate oxidation, while 42% of the tRNA(arg) from an argS(+) strain was charged. When deprived of leucine, leu argS or leu argS(+) strains grown with canavanine contained more than 60% charged tRNA(arg). Reverse phase column chromatography of periodate-oxidized tRNA from canavanine-grown argS and argS(+) strains showed no preferential charging of any isoaccepting species of tRNA(arg). Therefore, we failed to detect a specific arginyl-tRNA species that might be involved in repression by canavanine. However, the data suggest that canavanine repression of the arginine pathway occurs only when high levels of canavanyl-tRNA are present, and thus support the notion that arginyl-tRNA synthetase plays a role in generating a repression signal.


Specificity of interaction between the first enzyme for histidine biosynthesis and aminoacylated histidine transfer ribonucleic acid. The specificity of the interaction between phosphoribosyltransferase and partially purified preparations of various species of transfer ribonucleic acid (tRNA) was investigated with the use of a filter binding assay. The enzyme showed a higher affinity for histidyl-tRNA than for arginyl- or glutamyl-tRNA. Competition experiments revealed that the enzyme does not distinguish between the aminoacylated and deacylated forms of arginine tRNA or glutamic acid tRNA, since all the binding of the aminoacylated tRNA could be inhibited by deacylated tRNA. The enzyme does, however, distinguish between the aminoacylated and deacylated forms of histidine tRNA. Approximately 70% of the binding of aminoacylated histidine tRNA is specific, since only 30% of the binding could be inhibited by deacylated tRNA. The possibility that the regulatory role of phosphoribosyltransferase is carried out as a complex with histidyl-tRNA is consistent with these data.


Isoleucine and valine metabolism in Escherichia coli. 18. Induction of acetohydroxy acid isomeroreductase. The regulation by substrate induction of the acetohydroxy acid isomeroreductase was studied in Escherichia coli. Induction was inhibited by chloramphenicol and rifampin. The addition of rifampin resulted in a decay of the capacity to form isomeroreductase. This was attributed to the breakdown of the isomeroreductase messenger, which had a half-life of about 45 sec at 37 C. Induction of isomeroreductase was enhanced by including glucose in the medium. This effect was shown to be due in part to the lowering of the pH of the medium, which presumably made inducer entry more rapid.


Isoleucine and valine metabolism in Escherichia coli. XIX. Inhibition of isoleucine biosynthesis by glycyl-leucine. The inhibition of growth of the K-12 strain of Escherichia coli by glycyl-l-leucine observed originally by Simmonds and co-workers was investigated. The inhibition was reversed by isoleucine and those precursors of isoleucine beyond threonine in the biosynthetic pathway. Threonine reversed the inhibition poorly. With heavy cell suspensions, the inhibition was transient: the onset of growth followed the disappearance of the dipeptide from the medium and the appearance of glycine and leucine. Glycyl-leucine was shown to be an inhibitor of threonine deaminase (EC 4.2.1.16 l-threonine hydro-lyase [deaminating]). One kind of glycyl-leucine-resistant mutant had a threonine deaminase that was resistant to isoleucine and glycyl-leucine inhibition. The pattern of glycyl-leucine inhibition is compared with those of inhibition by isoleucine and by the weaker inhibitors leucine and valine.


Preparation of purified suspensions of Mycobacterium leprae and Mycobacterium lepraemurium from biopsy material.


Degradation of bacteriophage lambda deoxyribonucleic acid after restriction by Escherichia coli K-12. Wild-type bacteria which restrict the deoxyribonucleic acid (DNA) of infecting phage when the phage do not carry the proper host modification rapidly degrade that restricted DNA to acid-soluble products. The purified restriction enzyme acts as an endonuclease in vitro to cleave restrictable DNA and does not further degrade the DNA fragments produced. We have examined mutants of Escherichia coli K-12 which lack various nucleases in order to determine which nucleases are involved in the rapid acid solubilization in vivo of unmodified lambda DNA following restriction. Bacteria which are wild type, recA(-), or polA1(-) degrade about 50% of the unmodified phage DNA within 10 min of infection, with little subsequent degradation. Mutants which are recB(-) or recC(-) degrade unmodified DNA very slowly, solubilizing about 15% of the DNA by 10 min after infection. Two classes of phenotypic revertants of recB(-)/C(-) mutants were also tested. Bacteria which are sbcA(-) restrict poorly and do not degrade much of the restricted DNA. Bacteria which are sbcB(-) restrict normally. This mutation does not appear to affect degradation of restricted phage DNA in recB(-)/C(-) mutants, but such degradation is decreased in recB(+)/C(+) bacteria. The presence of a functional lambda exonuclease gene is not required for degradation after restriction.


Combinations of drugs against Mycobacterium leprae studied in mice.


Effects of colicins E1 and K on permeability to magnesium and cobaltous ions. The energy-dependent exchange of intracellular Mg(2+) with extracellular Mg(2+) or Co(2+) is inhibited by colicin E1 and, less strongly, by colicin K. Treatment with either colicin causes a net loss of intracellular Mg(2+). This loss begins immediately in cells treated with colicin E1, but in colicin K-treated cells the onset of Mg(2+) loss is delayed 1 to 10 min, depending upon the temperature and the multiplicity of colicin K. Both colicins differ from chemical inhibitors of energy-yielding metabolism; energy poisons block transport of Mg(2+) and Co(2+), but both colicins increase passive permeability to Mg(2+) and Co(2+). Inhibitors of energy-yielding metabolism (and of Mg(2+) exchange) block the initiation of Mg(2+) loss by either colicin, but do not stop colicin-promoted efflux once it has begun. Colicin E1 added before colicin K prevents the more rapid Mg(2+) efflux characteristic of colicin K-treated cells. Quantitative comparisons of the effects of colicins E1 and K upon permeability to Mg(2+) and Co(2+) lead us to conclude that the two colicins are not identical in their mode of action.


Factors affecting virulence of Shigella flexneri: defective methionine synthesis in an Escherichia coli-Shigella hybrid. An Escherichia coli-Shigella flexneri hybrid of intermediate virulence was studied to determine whether its shorter survival in host cells might be due to a metabolic defect. Investigation of its growth in minimal glucose medium showed that the hybrid, like its E. coli parent, had a longer lag phase and a slower growth rate than its virulent Shigella parent. Methionine was found to increase the growth rate of the hybrid. The Shigella parent of the hybrid can synthesize methionine normally, but the E. coli parent has a point mutation in its metA gene. Since it synthesizes enough methionine to grow slowly, it is postulated that the hybrid strain has a hybrid metA gene, that is, a gene composed partly of deoxyribonucleic acid (DNA) from E. coli, with the balance of the DNA from S. flexneri. Phage P1-mediated transduction, with the metA(-)E. coli parent as recipient and the Shigella parent as donor, yielded a few transductants that responded to methionine in the same way the hybrid did. Many more transductants of the hybrid type were produced when the hybrid strain was used as a donor. It is suggested that this poorly functioning gene acts synergistically with the hybrid strain's relaxed synthesis of ribonucleic acid to prevent its survival in the host.


Deletion mapping of the genes coding for HPr and enzyme I of the phosphoenolpyruvate: sugar phosphotransferase system in Salmonella typhimurium. Sugars transported by a bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) require two soluble proteins: HPr, a low-molecular-weight phosphate-carrier protein, and enzyme I. The structural genes coding for HPr (ptsH) and Enzyme I (ptsI) are shown to be cotransducible in Salmonella typhimurium. The gene order of this region of the Salmonella chromosome is cysA-trzA-ptsH-ptsI...(crr). A method for the isolation of trzA-pts deletion is described. One class of pts deletions extends through ptsH and into ptsI; a second class includes both ptsH and ptsI and extends into or through the crr gene. The crr gene either codes for or regulates the synthesis of a third PTS protein (factor III) which is sugar-specific. A hypothesis is presented for a mechanism of deletion formation.


Cross reactivity of Mycobacterium laprae and BCG. A report on further studies.


Mapping of the fabA locus for unsaturated fatty acid biosynthesis in Escherichia coli. fabA mutants of Escherichia coli require an appropriate unsaturated fatty acid for growth. The fabA locus has now been mapped at minute 21.5 of the linkage map of E. coli. The locus is cotransduced with pyrD and aroA but not with pyrC, purB, or pdxC. The clockwise order of markers in the region is pdxC, aroA, cmlB, pyrD, fabA, pyrC.


Isoleucine auxotrophy due to feedback hypersensitivity of biosynthetic threonine deaminase. Isoleucine-deficient mutants of Salmonella typhimurium were isolated. Three groups of mutants can be discerned by their nutritional requirements and enzyme patterns. (i) Mutants which grow with isoleucine alone are devoid of biosynthetic threonine deaminase (TD). (ii) Mutants growing with isoleucine and valine are devoid of transaminase B. (iii) Mutants growing with either isoleucine or threonine have normal levels of TD. However, the sensitivity of this enzyme to feedback inhibition by isoleucine is greatly enhanced. The inhibitory effect of isoleucine can be counterbalanced by high concentrations of threonine. These results indicate that the production of isoleucine in the mutants is restricted to a low level not sufficient to support the growth of the cells. This hypothesis is confirmed by studies with revertants of an isoleucine-threonine mutant. In nine revertants, wild-type properties of TD have been restored. In four revertants, the hypersensitivity of TD is unchanged, but the strains produce a greatly enhanced quantity of threonine, which is excreted into the culture medium. It follows, that hypersensitivity of TD to inhibition by isoleucine is the cause of the nutritional requirement of isoleucine-threonine mutants.


Effect of deoxyribonucleic acid ligands on deoxyribonucleases and deoxyribonucleic acid polymerase I of Escherichia coli K-12. Endonuclease I, exonuclease I, and exonuclease II-deoxyribonucleic acid (DNA) polymerase I activities are not vital functions in Escherichia coli, although the latter two enzymes have been indirectly shown to be involved in DNA repair processes. Acridines such as acridine orange and proflavine interfere with repair in vivo, and we find that such compounds inhibit the in vitro activity of exonuclease I and DNA polymerase I but stimulate endonuclease I activity and hydrolysis of p-nitrophenyl thymidine-5'-phosphate by exonuclease II. Another acridine, 10-methylacridinium chloride, binds strongly to DNA but is relatively inert both in vivo and in vitro. These experiments suggest that acridines affect enzyme activity by interacting with the enzyme directly as well as with DNA. Resulting conformational changes in the DNA-dependent enzymes might explain why similar acridines which form similar DNA complexes have such a wide range of physiological effects. Differential sensitivity of exonuclease I and DNA polymerase I to acridine inhibition relative to other DNA-dependent enzymes may contribute to the acridine sensitivity of DNA repair.


Comparative electrophoretic and amino acid analyses of isolated membranes from Streptococcus pyogenes and stabilized L-form. Major quantitative, but not qualitative, differences in the various species of proteins in purified membranes from Streptococcus pyogenes and its stabilized L-form have been demonstrated by acidic and alkaline disc gel electrophoresis with and without urea. The fact that no significant differences in the amino acid content or composition between these two membranes could be demonstrated emphasizes that these results are probably due to changes in the relative amounts of the various species of proteins in this subcellular component. The possibility of these protein changes in the L-form membrane being related to its inability to synthesize a rigid cell wall is discussed. Finally, phage-associated lysin, routinely used for removal of the group A streptococcal cell wall, does not appear to affect the protein profile or amino acid composition of the membrane either metabolically or nonmetabolically.


Regulation of macromolecular synthesis by putrescine in a conditional Escherichia coli putrescine auxotroph. Addition of putrescine to a slowly growing, polyamine-starved Escherichia coli K-12 mutant conditionally incapable of synthesizing putrescine causes the immediate stimulation of protein synthesis. After a period ranging from 60 to 105 min, ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) syntheses are also stimulated and rapid cellular division begins. Chloramphenicol blocks this rapid cellular division, although addition of the specific DNA synthesis inhibitor, nalidixic acid, has no effect on cell division. By sucrose gradient analysis and diethylaminoethyl-cellulose chromatography, the proteins initially made in response to putrescine appear to be composed of many classes, including membrane-bound proteins. However, the synthesis of ribosomal subunits is not altered during this period. A possible role for putrescine in either the stimulation of messenger RNA transcription or in translation is suggested.


Chemotaxis toward amino acids in Escherichia coli. Escherichia coli cells are shown to be attracted to the l-amino acids alanine, asparagine, aspartate, cysteine, glutamate, glycine, methionine, serine, and threonine, but not to arginine, cystine, glutamine, histidine, isoleucine, leucine, lysine, phenylalanine, tryptophan, tyrosine, or valine. Bacteria grown in a proline-containing medium were, in addition, attracted to proline. Chemotaxis toward amino acids is shown to be mediated by at least two detection systems, the aspartate and serine chemoreceptors. The aspartate chemoreceptor was nonfunctional in the aspartate taxis mutant, which showed virtually no chemotaxis toward aspartate, glutamate, or methionine, and reduced taxis toward alanine, asparagine, cysteine, glycine, and serine. The serine chemoreceptor was nonfunctional in the serine taxis mutant, which was defective in taxis toward alanine, asparagine, cysteine, glycine, and serine, and which showed no chemotaxis toward threonine. Additional data concerning the specificities of the amino acid chemoreceptors with regard to amino acid analogues are also presented. Finally, two essentially nonoxidizable amino acid analogues, alpha-aminoisobutyrate and alpha-methylaspartate, are shown to be attractants for E. coli, demonstrating that extensive metabolism of attractants is not required for amino acid taxis.


Variable ammonia production among smooth and rough strains of Pseudomonas pseudomallei: resemblance to bacteriocin production. The colonial morphology of some strains of Pseudomonas pseudomallei was correlated with certain biochemical and physiological traits. After 3 days of growth on Wahba or heart infusion agars, smooth-colony strains generated toxic amounts of ammonia. Under the same conditions, the rough strains simultaneously produced oxalic acid which decreased the inhibitory concentration of ammonia. The ammonia-ammonium concentrations in smooth cultures exhibited certain bacteriocin-like characteristics. An unusually stable, smooth strain (strain 165) was chosen to compare and emphasize any differences with typical, rough strain 7815. Three-day-old smooth cultures grown on Wahba agar containing 3% (w/v) glycerol demonstrated ammonia toxicity. The substitution of glucose for glycerol completely obviated this toxicity. In highly aerated Wahba broth containing glucose, the amount of ammonia found in strain 165 smooth cultures and the amount of oxalic acid found in strain 7815 rough cultures were greatly reduced. In Difco nitrate broth smooth strain 165 did not form gas, and it reduced nitrate to nitrite only. Strain 7815 produced a gas and reduced both nitrate and nitrite.


Effects of phosphonic acid analogues of glycerol-3-phosphate on the growth of Escherichia coli. The four-carbon phosphonate, 3,4-dihydroxybutyl-1-phosphonate, is similar to glycerol-3-phosphate in its ability to inhibit cell growth of Escherichia coli strain 8 cultured in low-phosphate synthetic medium supplemented with either succinate or casein hydrolysate as the sole carbon source. The three-carbon phosphonate, 2,3-dihydroxypropyl-1-phosphonate, does not appear to exhibit a similar effect. The inhibition caused by the four-carbon phosphonate differs from that caused by glycerol-3-phosphate in at least three ways. (i) Its inhibitory effect is not offset by the presence of glucose in the culture medium. (ii) It is capable of exerting its inhibitory effect on cells containing an active aerobic glycerol-3-phosphate dehydrogenase. (iii) Its inhibitory effect is maintained in synthetic medium containing high concentrations of inorganic phosphate. The four-carbon phosphonate appears to be bacteriostatic and inhibits the uptake of labeled glycerol-3-phosphate by E. coli strain 8.


Mutant of Escherichia coli deficient in the synthesis of cis-vaccenic acid. A temperature-sensitive unsaturated fatty acid (fabA) auxotroph of Escherichia coli was found also to be deficient in the elongation of palmitoleic acid to cis-vaccenic acid. Reversion and transductional analyses demonstrate that this second phenotype and the fabA mutation are independent in action and are not cotransduced. The deficiency in conversion of palmitoleic acid to cis-vaccenic acid was also demonstrated in vitro, and these results strongly suggest this phenotype is due to a deficiency in an elongation enzyme. We suggest that the phenotype may have been selected during growth because it can physiologically compensate for the fabA lesion. In fab(+) strains, the inability to synthesize cis-vaccenic acid is physiologically asymptomatic. Such strains grow normally at all temperatures tested and are not sodium sensitive. Although the parental strain has an increased amount of cis-vaccenic acid in cells grown at 15 C, the mutant does not. Since the mutant grows normally at 15 C, the data indicate that increased amounts of cis-vaccenic acid are not required for growth at 15 C.


Isolation of transducing bacteriophages for the histidine and isoleucine-valine operons in Escherichia coli K-12. In vitro studies have been of great value in elucidating the mechanism of the regulation of several bacterial operons. To obtain a deoxyribonucleic acid preparation enriched for the histidine (his) and for the isoleucine-valine (ilv) operons, we have isolated bacteriophages carrying the his and the ilv regions of the Escherichia coli chromosome. Transposition of the his operon to a site close to the att80 region of the E. coli chromosome has been carried out selecting for integration of a temperature-sensitive F'his(+) in the tonB locus. This transposed strain has been lysogenized with phi80i(lambda). Upon induction of the lysogen, His(+) transductants have been isolated, which, on further induction give rise to HFT (high frequency of transduction) lysates. Preliminary characterization of the transducing phage is reported. The ilv operon, carried on an F' particle, has been fused to an episome carrying the att80 region. The fused episome has been lysogenized with phi80i lambdat68. Upon induction of the lysogen, Ilv(+) transductants have been isolated which on further induction give rise to HFT lysates.


Adenine phosphoribosyltransferase in Mycoplasma mycoides and Escherichia coli. Some kinetic properties of the adenine phosphoribosyltransferases from Escherichia coli and Mycoplasma mycoides have been studied. For the E. coli enzyme, Michaelis constants for adenine and 5-phosphoribosyl-1-pyrophosphate (PRPP) are 1.3 and 10 mum, respectively. Adenosine monophosphate, the most effective nucleotide inhibitor, inhibits competitively with respect to PRPP, the inhibition constant being 26 mum. The M. mycoides enzyme has more complex kinetics. The response to increasing PRPP concentration is sigmoidal, the degree of sigmoidality depending on both the concentration of adenine and the pH. At low PRPP levels, high concentrations of adenine are inhibitory. Guanosine monophosphate is the most effective inhibitor, being inhibitory at all pH values, but other nucleotides have been found to activate at pH 7 and inhibit at pH 8. The elution profile of the M. mycoides enzyme from Sephadex suggests an association of enzyme subunits in the presence of PRPP. This is consistent with the observed kinetics if the associated form has increased stability and activity.


Effect of pH on adenine and amino acid uptake during sporulation in Saccharomyces cerevisiae. During the early stages of sporulation in Saccharomyces cerevisiae, the pH of the acetate sporulation medium rises to values of 8.0 or higher. Associated with this rise in pH is a reduced cell permeability to certain precursors of ribonucleic acid (RNA), deoxyribonucleic acid or protein. Uptake of adenine, alanine, and leucine was optimal at pH 5.6 to 6.0, but sporulation was inhibited when the sporulation medium was buffered below pH 7.0. Cellular impermeability can be largely overcome by adjusting the acetate sporulation medium to pH 6.0 for optimal uptake of (14) C-adenine during short pulses without any apparent effect on sporulation. Sporulating cells pulse-labeled 20 min at pH 6.0 incorporated 40 times more (14)C-adenine into RNA than sporulating cells pulse-labeled at pH 8.0. This increased incorporation can be attributed to a 100-fold increase in labeled adenosine triphosphate in cells pulse-labeled at pH 6.0 where maximum uptake occurs.


Purification and properties of the flavine-stimulated anaerobic L- -glycerophosphate dehydrogenase of Escherichia coli. The anaerobic l-alpha-glycerophosphate (l-alpha-GP) dehydrogenase of Escherichia coli was purified approximately 40-fold. The activity of the dehydrogenase, although not affected by the addition of pyridine nucleotides, was stimulated three- to fourfold by flavine adenine dinucleotide (K(m) about 10(-7)m) and up to 10-fold by flavine mononucleotide (K(m) about 10(-4)m). Maximal activity of the enzyme was found only in the combined presence of saturating concentrations of both flavines (stimulation by a factor of 10 to 15). The dependence of the rate of the reaction on the concentration of l-alpha-GP was complex in the presence of both flavines, but in the presence of flavine adenine dinucleotide alone the kinetics were of the Michaelis-Menten type with the K(m) for l-alpha-GP being about 10(-4)m. The product of the reaction was identified as dihydroxyacetone phosphate, and the molecular weight of the dehydrogenase was estimated to be 80,000 +/- 10,000. Phenazine methosulfate, menadione and ferricyanide served as artificial acceptors for the dehydrogenase. The enzyme was sensitive to iodoacetate, p-chloromercuribenzoate, and N-ethymaleimide.


Reversion of ribosomal helix formation in Escherichia coli. After transfer into fresh medium, Escherichia coli cells containing ribosomal helices resume growth without a lag period. The helices disappear within 15 min after transfer, the number of 70S ribosomes decreases, and a steady-state ribosomal profile appears within one cell generation time. Subunits isolated from the helices support in vitro protein synthesis, but efficiency is optimal only when supplemented with an undetermined factor that is contained in the S-100 fraction of log-phase cells. The data suggest a possible role of helices as ribosomal reserve units.


Partial purification and characterization of S-adenosylhomocysteine hydrolase isolated from Saccharomyces cerevisiae. S-Adenosylhomocysteine (SAH) hydrolase was purified 25-fold from bakers' yeast by chemical methods and column chromatography. The purified enzyme could readily synthesize SAH from adenosine and homocysteine, but could hydrolyze only negligible amounts of SAH. The purified enzyme showed no activity towards S-adenosylmethionine, methylthioadenosine, or adenosine. Several nucleotides, sulfhydryl compounds, and ribose could not replace adenosine or homocysteine in the reaction mixture. SAH could be hydrolyzed by SAH hydrolase if commercial adenosine deaminase was included in the reaction mixture. Under these conditions l-homocysteine could act as a product inhibitor. A number of compounds structurally similar to adenosine and homocysteine were found to inhibit synthesis of SAH from adenosine and homocysteine. The strongest inhibitors were adenine, adenosine-3'-monophosphate, adenosine-2'-monophosphate, adenosine diphosphate, adenosine triphosphate, and adenosine-5'-monophosphate. The biosynthetic and hydrolytic activity of SAH hydrolase in yeast cell ghosts was similar to the activity of the enzyme in vitro.


Transfer among Erwinia spp. and other enterobacteria of antibiotic resistance carried on R factors. Antibiotic resistance carried on R factors was transferred by conjugation from Escherichia coli B/r and Shigella flexneri 1a to Erwinia spp. Tetracycline resistance (TetR) carried on R factor R100 drd-56 was transferred from E. coli B/r to strains of Erwinia amylovora, E. aroideae, E. atroseptica, E. chrysanthemi, E. cytolytica, E. dissolvens, E. herbicola, E. nigrifluens, and E. nimipressuralis, but not to strains of Erwinia carotovora, E. carnegieana, E. dieffenbachiae, E. oleraceae, and E. quercina. Multiple antibiotic resistance (chloramphenicol, streptomycin, tetracycline; ChlR-StrR-TetR) carried on R factor SR1 was transferred from a clinical isolate of S. flexneri 1a to strains of E. aroideae, E. chrysanthemi, E. herbicola, and E. nigrifluens, but not to strains of other Erwinia spp. The frequency of this transfer was low with receptive cultures of Erwinia spp. and E. coli (F(-) strain). Antibiotic resistance in the exconjugants showed varying degrees of stability in the presence or absence of acridine orange, depending on the strain tested. The frequencies of segregation to drug susceptibility in the presence of acridine orange, though low, suggest that the elements exist as plasmids in the majority of the Erwinia exconjugants. Multiple antibiotic resistance (ChlR-StrR-TetR) was found to segregate into various resistance classes (ChlR-StrR, StrR-TetR, TetR, StrR, and none) in these exconjugants. The exconjugants of E. amylovora, E. herbicola, and E. nigrifluens, to which R100 drd-56 was transferred from E. coli B/r, were sensitive to the male (F)-specific phage M13. There was a positive correlation between the susceptibility of exconjugants to the F-specific phage M13 and their ability to transfer R100 drd-56 to the recipient cultures of Escherichia coli, Erwinia herbicola, Salmonella typhimurium, and Shigella dysenteriae. Exceptions were, however, noted with Erwinia dissolvens and E. nimipressuralis exconjugants harboring R100 drd-56; these exconjugants, although not susceptible to M13, transferred R100 drd-56 to the recipient cultures. The frequency of transfer of R100 drd-56 and the levels of resistance to tetracycline in Erwinia exconjugants were found to differ markedly depending upon the strain employed. Transfer of multiple antibiotic resistance (ChlR-StrR-TetR) from Erwinia exconjugants was not obtained in preliminary trials with an E. coli F(-) strain as the recipient culture.


Exosporium formation in sporulating cells of Clostridium botulinum 78A. In sporulating cells of Clostridium botulinum type A (NCA strain 78A), formation of exosporia was initiated laterally in the sporangia before the synthesis of the spore cortex. Mature spores were enveloped by multilayered exosporia; the layers were uniform in appearance, approximately 3 nm thick, with a center-to-center distance of 7 nm.


P22-mediated transduction analysis of the rough A (rfa) region of the chromosome of Salmonella typhimurium. Seven temperature-sensitive rough mutants of Salmonella typhimurium were found to be sensitive to smooth-specific phages at low temperature (25 C, 30 C) and resistant or partially resistant to rough-specific phages, whereas at high temperatures (37 C, 45 C) they were resistant or partially resistant to smooth-specific phages but sensitive to rough-specific phages. These data indicate that at low temperature each strain makes lipopolysaccharide which is relatively normal, but at high temperatures O-specific side chains are not added to the lipopolysaccharide. At 45 C, these strains have the R-res-1 or R-res-2 phage sensitivity phenotype, and their genetic lesions map by P22-mediated transduction in the rfa gene cluster between cysE-pyrE, suggesting a mutation in genes with transferase functions. P22-mediated joint transduction with temperature-sensitive rfa mutants, leaky rfa mutants, and rfa P22 lysogens have shown the following order of genes in the S. typhimurium linkage map: xyl-mtlA-mtlB-cysE-rfaF-rfaG-pyrE. An rfaE allele was not jointly transduced in the cysE-pyrE segment.


Synchronized division in Escherichia coli: an integral portion of culture growth. A single synchronized division normally occurs in Escherichia coli just prior to stationary phase, irrespective of growth medium and lineage or sex of the bacterium.


Toxicity of irradiated medium for repair-deficient strains of Escherichia coli. Nutrient agar medium is made highly toxic to certain repair-deficient strains of Escherichia coli by exposure of the uninoculated plates to radiation from cool-white fluorescent lamps or black-light fluorescent lamps. This sensitivity is associated with the genetic deficiencies, fil, phr, and recA. Repair-sufficient and uvr strains are only slightly affected by the irradiated media. The poor growth and reduced plating efficiency frequently associated with BPhr and recA strains are very likely caused by inadvertent exposure of the medium to fluorescent light.


Loss of deoxyribonucleic acid-thymine during thymine starvation of Escherichia coli. A substantial loss of deoxyribonucleic acid-thymine occurs during thymine starvation of several thymine auxotrophs derived from Escherichia coli strains B, 15, and K-12.


Insertion of the F factor into the cluster of rfa (rough A) genes of Salmonella typhimurium. From F(+) strains of Salmonella typhimurium, isolates were obtained representing two new classes of Hfr strains, HfrK1 and HfrK2, in which the insertion of the F factor into the rfa genes results in chromosome mobilization either clockwise or anticlockwise from rfa, and in the Rfa phenotype. The point of insertion of the F factor into the cluster of rfa genes, revealed by studies of the early transfer of their normal alleles, is as follows: xyl-cysE-rfa-657 (HfrK2-1, SA540 -->)-(<-- HfrK1-1, SA458)-rfaG-(<-- HfrK1-2, SA464)-pyrE-metA


Toxicity of L-Tryptophan photoproduct on recombinationless (rec) mutants of Salmonella typhimurium. l-Tryptophan after exposure to black light becomes toxic for recombinationless (rec) mutants of Salmonella typhimurium. Fifty-six radiation-sensitive mutants were screened for sensitivity to the tryptophan photoproduct; the rec and exr (X-ray sensitive) mutants are sensitive, whereas the uvr, hcr, and wild-type strains are resistant. A number of catabolic products of tryptophan and compounds related to tryptophan were screened for toxicity to rec strain; these are nontoxic or far less toxic for rec strains than irradiated l-tryptophan. The toxic photoproduct is relatively stable to drying and basic hydrolysis at 90 C, indicating that it is a stable organic compound, eliminating peroxide as the toxic component. It was also observed that the toxic product is a photooxidation product since it is formed only when l-tryptophan is irradiated in the presence of air.


Initiation of deoxyribonucleic acid replication in Escherichia coli B-r: chronology of events and transcriptional control of initiation. Three processes necessary for the initiation of deoxyribonucleic acid replication have been separated in time in synchronously growing Escherichia coli B/r. One can be inhibited with 2 mug of chloramphenicol per ml and occurs about 20 min prior to initiation. A second step, occurring 5 to 10 min prior to initiation, is sensitive to 4 to 30 mug of chloramphenicol per ml. A third process occurs at the time of initiation and can be inhibited with rifampin. The experiments suggest that transcription itself, or the synthesis of a relatively small ribonucleic acid, is required for initiation of replication.


Nature of the so-called fibrillar component in the segregated nucleolus after treatment of actinomycin D.


Adsorption of bacteriophage phiX174 to isolated bacterial cell walls.


Studies on heterologous antilymphocyte and antithymocyte sera. V. Loss or retention of immunosuppressive activity after absorption with sheep erythrocytes.


Ontogeny of bursal function in chicken. I. Embryonic stem cell for humoral immunity.


Ontogeny of bursal function in chicken. II. Postembryonic stem cell for humoral immunity.


Anti-DNA plaque-forming cells (PFC) and rosette-forming cells (RFC) in spleens of NZB-WF female (B-W) mice.


The immune recognition of TA3 tumors, its facilitation by endotoxin, and abrogation by ascites fluid.


A plaque assay on agar for detection of gram-negative bacilli sensitive to complement.


Measurement of antibody release from single cells. I.


Measurement of antibody release from single cells. II.


Genetic regulation of the thymus dependent humoral immune response in leukemia prone AKR (H-2 k ) and nonleukemic C3H (H-2 k ) mice. Description of genetic control of the immune response at the level of proliferation.


Lionel Sharples Penrose (1898-1972), MA,MD,DSc,FRCP,FRS.


Gene duplication, mutation load, and mammalian genetic regulatory systems.


Familial chronic muco-cutaneous candidiasis.


Messenger RNA in animal cells.

Messenger RNA in animal cells.


An evaluation of transfer factor as immunotherapy for patients with lepromatous leprosy.


Annual discourse--organ replacement, facial deformity, and plastic surgery.


Isolated gonadotropin deficiency with response to luteinizing-hormone-releasing hormone.


Clinical trial of tranexamic acid.

Clinical trial of tranexamic acid.


How to take care of the poor.

How to take care of the poor.


Assay for gentamicin.

Assay for gentamicin.


Respiratory therapy--a new forntier in hospital medicine.


Trigeminal neuralgia. Report of a bilateral case.


Dental plaque reduction with an antibacterial mouth rinse. II. A comparison of clinical and physical scoring methods.


A controlled evaluation of lithium prophylaxis in affective disorders.


Dietary fibre and coronary heart disease.


Evaluation of the measurement of the renal blood flow by the  133 Xe washout technique in dogs.


Helminths and allotransplantation.

Helminths and allotransplantation.


Effects of synthetic luteinizing hormone-releasing hormone (LH-RH) on serum gonadotropins (LH and FSH) in normal children and adults.


Microscopy: yesterday and tomorrow.

Microscopy: yesterday and tomorrow.


Optical function of myoids.

Optical function of myoids.


A memorial resolution for Philip Edward Smith.


Effects of dextroamphetamine, chlorpromazine, and hydroxyzine on behavior and performance in hyperactive children.


On the bicentenary of the birth of Esquirol (1772-1840), the first complete psychiatrist.


Group psychotherapy in the Soviet Union.


Reduction of the psychotomimetic and circulatory side-effects of ketamine by droperidol.


Primary and chronic thromboembolic pulmonary hypertension. Nosologic spectrum.


Mycobacterial agglutination-inhibition test. The mycobacterial agglutination-inhibition test (MAIT) is described as a modification of the mycobacterial agglutination of Schaefer (MATS). It is an organized assemblage of absorption and agglutination tests which is especially useful in the identification of Mycobacterium avium isolates normally excluded from serological identification because of unstable cell suspension characteristics. The identity of 100 unstable M. avium and 3 unstable Mycobacterium intracellulare isolates was determined by the MAIT method and by animal pathogenicity tests. The comparability of the MAIT and MATS methods was demonstrated by testing 10 stable M. avium and 10 stable M. intracellulare isolates by both methods and obtaining the same serological identification for each culture. The reproducibility of the MAIT was confirmed when the same result was obtained in three consecutive tests on each of the 123 cultures used in this evaluation.


Salmonellae as an index of pollution of surface waters. Screening enrichments of surface water specimens by means of a polyvalent fluorescent antibody reagent for the salmonellae yielded approximately 60% more positive specimens than was obtained by cultural procedures. It is not known what fraction of the excess of fluorescent antibody-positive over culturally positive specimens represents staining of non-salmonellae or non-arizonae as opposed to the staining of non-cultivatable organisms of these two genera. Cotton gauze and rayon-polypropylene fiber swabs were equally sensitive for collecting salmonellae from the streams examined. Tetrathionate enrichment incubated at 41.5 C appeared to be superior to selenite-cystine for isolation of salmonellae from surface waters. Twenty-eight serotypes of Salmonella and two serotypes of Arizona were identified in the 121 positive specimens. In water rated moderately polluted, 65% of all specimens tested were positive; in minimally polluted waters, 38% were positive; and in unpolluted streams, 44% were positive.


Evaluation of modified R-B system for identification of members of the family Enterobacteriaceae. In a paired, double-blind study, the modified ("Beckford tube") R-B system was compared with conventional bacteriological procedures for the identification of members of the family Enterobacteriaceae from clinical isolates and stock cultures. The tests in the R-B system yielding positive reactions comparable to those predicted by Ewing's taxonomic classification of Enterobacteriaceae were production of hydrogen sulfide and presence of lysine and ornithine decarboxylasè activities. The test reactions in the R-B system found to be comparable to those in the conventional method were fermentation of glucose, hydrogen sulfide production, and lysine and ornithine decarboxylase activities. The production of gas from glucose was positive in the R-B system more often than in the conventional method; however, the motility test and the production of indole were positive less often in the R-B system. Adequate preliminary identification of the Enterobacteriaceae with the R-B system is enhanced if Simmons' citrate and Christensen's urea tests are used concomitantly. These findings emphasize the manufacturer's instructions that, in interpretation of results, colonial morphology and biochemical reactions must be used concurrently to make an accurate identification.


Microbial degradation of crude oil: factors affecting the dispersion in sea water by mixed and pure cultures. By means of the enrichment culture technique, a mixed population of microorganisms was obtained which catalyzed the dispersion of crude oil in supplemented sea water. From this enrichment culture, eight pure cultures were isolated and studied. Only one of the isolates (RAG-1) brought about a significant dispersion of crude oil. RAG-1 has been tentatively characterized as a member of the genus Arthrobacter. The other seven isolates gave rise to colonies on supplemented oil agar, but were neither able to disperse oil nor to stimulate the dispersion catalyzed by RAG-1. The dispersion of crude oil by either RAG-1 or the enrichment culture was absolutely dependent on exogenous sources of nitrogen and phosphorous and completely inhibited by 10(-2)m azide. The increase in cell number of RAG-1 was directly proportional to the concentration of crude oil added to the medium over the range 0.05 to 1.0 mg/ml. Within this linear region, 1.0 mg of crude oil yielded 9 x 10(7) cells and approximately 65% of the oil was converted into a nonbenzene extractable form. Accompanying the emulsification was a decrease in the pH from 7.6 to 5.0. Acidic conditions, however, were neither necessary nor sufficient for oil dispersion. When sea water was supplemented with 0.029 mm K(2)HPO(4) and 3.8 mm (NH(4))(2)SO(4) and inoculated with RAG-1, oil dispersion occurred within 1 day. This dispersion could also be brought about by the supernatant following separation of the cells from the medium. Similarly, the supernatant obtained following growth of RAG-1 on hexadecane was capable of emulsifying crude oil in 60 min.


Nitrite burn in fermented sausage.

Nitrite burn in fermented sausage. A rare outbreak of anaerobic nitrite burn in fermented sausage afforded the isolation and characterization of the offending microorgansim which was identified as a Staphylococcus sp. Unlike most staphylococci, this organism reduces nitrite as well as nitrate.


Comparison of immunization methods for producing reference adenovirus antisera in horses. Horses were immunized by a variety of inoculation procedures designed to determine the most efficient method of producing antisera to adenovirus types 25 to 31. The procedures evaluated included immunization by (i) direct intravenous (iv) injection, (ii) iv infusion, (iii) intramuscular (im) injection of virus with and without Freund's incomplete adjuvant, (iv) combined iv and im injections, and (v) combined iv infusion and im injection. The im schedule (no. 3) was superior to the others in terms of immunizing antigen and time required, and hemagglutination-inhibition (HI) and serum-neutralizing (SN) antibody levels produced. HI and SN tests performed with sera before and after heating at 56 C for 30 min showed that heat-inactivation was not necessary for tests with equine antisera.


Three-tube method for screening stool cultures for Salmonella and Shigella. A three-tube method developed is described as a screening test for non-lactose-fermenting organisms isolated from stool cultures. To evaluate the method, 976 strains of gram-negative bacilli were tested. All strains of Salmonella and Shigella were correctly identified generically.


Fermentation process for double-stranded ribonucleic acid, an interferon inducer. Double-stranded ribonucleic acid (ds-RNA) isolated from Escherichia coli infected with bacteriophage MS2 is a potent interferon inducer. High levels of ds-RNA are formed in nonpermissive cells infected with MU9, an amber coat protein mutant of MS2. This mutant has been used to develop a process for large-scale ds-RNA production. Preparation of quantities of MU9 lysate sufficient for ds-RNA production in fermentors is described. Over 300 mug of ds-RNA/ml can be accumulated after MU9 infection of cultures grown to high density in corn steep liquor medium. This is approximately 300 times the amount of ds-RNA made by MS2 infection of cells grown in tryptone medium. Maximum ds-RNA formation requires only 3 hr. The ds-RNA is stable and remains inside nonaerated cells for at least 17 hr.


Effect of water activity on enterotoxin A production and growth of Staphylococcus aureus. Previous studies indicated that enterotoxin B production by staphylococci was strongly inhibited by slight reductions in water activity (a(w)) levels. Similar studies reported herein, employing an enterotoxin A-producing strain, indicated that this organism was capable of producing enterotoxin at a much lower a(w) level than that required for enterotoxin B production. Staphylococcal growth rates were slowed by decreased a(w) levels in all media tested; however, final cell counts did not drop below 10(8)/ml in the media with the lowest a(w) levels.


Vibrio parahaemolyticus gastroenteritis in Maryland: laboratory aspects. Vibrio parahaemolyticus was the etiological agent in three food-related epidemics of gastroenteritis in Maryland, during August 1971. These outbreaks involved crab food products. Fifteen isolates of V. parahaemolyticus were made which included 11 from patients and 4 from foods. Serotype 04:K11 was the cause of the outbreaks. It was recovered from patients in each outbreak and gave a positive Kanagawa reaction, an indication of enteropathogenicity. Other patient isolates included types 03:K30, 03:K33, and an untypable isolate, all of which were Kanagawa negative. Food isolates included serotypes 03:K30, 02:K28, and two untypable isolates, all of which were Kanagawa negative. The outbreaks reported in this paper constitute the first confirmed foodborne epidemics due to V. parahaemolyticus in the United States. Methods for the isolation and identification of V. parahaemolyticus are presented, including a procedure for the simple conversion of conventional laboratory media into suitable culture media for this halophilic organism.


API system: a multitube micromethod for identification of Enterobacteriaceae. The API system for identification of Enterobacteriaceae was evaluated with 366 cultures. Overall accuracy of identification was 96.4%; of the 13 cultures misidentified, 7 were atypical strains.


Radiation sterilization of prototype military foods: low-temperature irradiation of codfish cake, corned beef, and pork sausage. "Screening" packs comprising 10 lots each of codfish cake, corned beef, and pork sausage, each lot containing about 10(6) spores of a different strain (five type A and five type B) of Clostridium botulinum per can, were irradiated at -30 +/- 10 C with a series of increasing doses (20 replicate cans/dose) of (60)Co gamma rays. The cans were incubated for 3 months at 30 C and examined for swelling, toxin, and recoverable botulinal cells. Based on the latter criterion of spoilage, median lethal dose (LD(50)) and D values were estimated for each strain in each food. The most resistant strain in codfish cake, corned beef, and pork sausage was, respectively, 53B, 77A, and 41B. There was no clear-cut trend in the comparative order of resistance between the two antigenic types among the three foods. LD(50) values gave essentially the same order of resistances as the D values and may be used interchangeably with the latter for the 10 test organisms. "Clearance" packs consisting of the most resistant strain (about 10(7) spores/can) with its respective food were irradiated with a variety of doses at -30 +/- 10 C, using 100 replicate cans/dose (about 10(9) spores/dose). These packs were incubated for 6 months at 30 C and assayed for the three types of spoilage. Based on recoverable cells, the experimental sterilizing doses (ESD) for codfish cake, corned beef, and pork sausage were 2.5< ESD </= 3.0, 2.0 < ESD </= 2.5, and 1.5 < ESD </= 2.0 Mrad, in that order. Assuming exponential spore death, the 12D values, or minimal radiation doses (MRD), were 3.24, 2.44, and 2.65 Mrad, respectively. Estimation of the MRD values by a method which assumes that spore death in the cans follows a normal distribution, yielded 3.09, 2.57, and 2.39 Mrad, respectively. Weibull analyis of the pooled 10-strain viable cell spoilage data of the screening packs for codfish cake or corned beef suggested that spore death in the cans follows a normal distribution yielded 3.09, 2.57, pooled data were not amenable to such analysis. Sublethal doses (0.5, 0.75 Mrad) increased the visible spoilage rate of corned beef over that of unirradiated controls. Apparently radiation-injured spores of C. botulinum were sensitized to the presence of food additives such as curing salts, NaCl, and spices.


Comparison of three techniques for the total count of anaerobes from intestinal contents of pigs. For the total count of anaerobes from cecal and colon contents of pigs, the roll-tube method of Hungate, the anaerobic ringed-plate technique of Van der Heyde, and incubation of petri dishes in anaerobic jars were compared.


Salmonellae and Edwardsiella tarda in gull feces: a source of contamination in fish processing plants. The incidence of Salmonella and Edwardsiella tarda in gull feces on the Oregon coast was studied to determine the role these birds may have in the contamination of fish products with these organisms. Approximately 2.1 and 0.4% of 521 fecal specimens examined were found to contain Salmonella or E. tarda, respectively.


Method for simultaneous detection of proteinase and esterase activities in extremely halophilic bacteria. A method was developed for simultaneous detection of proteinase and esterase activity in extremely halophilic bacteria by combining Tween hydrolysis and gelatin hydrolysis on a single plate.


Methotrexate and prednisone in pemphigus vulgaris. Therapeutic results obtained in 36 patients between 1961 and 1970.


Contraceptive conundrum. I.

Contraceptive conundrum. I.


In memoriam. Henry E. Michelson, MD.

In memoriam. Henry E. Michelson, MD.


High-speed biopsy punch for electron microscopic studies of human skin.


Arizona's territorial tales.

Arizona's territorial tales.


Sir Reginald Watson-Jones.

Sir Reginald Watson-Jones.


Breast lesion classification by computer and xeroradiograph.


Delayed distant metastasis from a subcutaneous sacrococcygeal ependymoma. Case report, with tissue culture, ultrastructural observations, and review of the literature.


Thomas Robertson, naval surgeon, 1793-1828.


Presentation of the Julius Friedenwald Medal to Jacob Earl Thomas.


The mind-body issue in early twentieth-century American medicine.


Effect of regular emptying of the gallbladder on gallstone formation in the rabbit.


Rudolf Schindler's role in the development of gastroscopy.


Walter B. Cannon's contribution to gastroenterology.


Pancreatic scanning: a review.

Pancreatic scanning: a review.


Cytofluorometric determination of DNA and protein in the nuclei and nucleoli of Physarum polycephalum during the intermitotic period.


Antagonistic effects of bacterial endotoxin and phytohaemagglutinin upon the primary immune response.


Release of intracellular constituents from rabbit polymorphonuclear leukocytes exposed to soluble and insoluble immune complexes.


In memoriam: Karl T. Neubuerger, M.D. (1890-1972).


Reconstructive surgery of the oral cavity and pharynx following extensive resections in head and neck regions.


Henry More's "Circulatio Sanguinis": an unexamined poem in praise of Harvey.


Thoma's Oral Pathology.

Thoma's Oral Pathology.


A clinical comparison of a new low abrasive dentifrice with intermediate and high abrasive dentifrices.


Electrical analogues of methods for continuous positive-pressure ventilation.


The surgical anatomy of sternal blood supply.


Management of injuries of the innominate and proximal left common carotid arteries.


The morphological basis for understanding middle ear effusions. An electron microscopic, cytochemical, and autoradiographic investigation.


Voter participation of the EMR: a review of the literature.


The development of thoracic surgery in the upper Mid-West.


Rare oral viral disorders (molluscum contagiosum, localized keratoacanthoma, verrucae, condyloma acuminatum, and focal epithelial hyperplasia).


Diagnostic problems in coronary heart disease.


A tribute to Robert S. Stone, M.D.

A tribute to Robert S. Stone, M.D.


Osteosclerosis in hyperparathyroidism.

Osteosclerosis in hyperparathyroidism.


Electronic radiography in stereotaxic thrombosis of intracranial aneurysms and catheter embolization of cerebral arteriovenous malformations.


Henrietta Snow Hayden Corrigan, Ph.D. 1898-1971.


D. Reed Hanely, M.D. 1903-1972.

D. Reed Hanely, M.D. 1903-1972.


Pathology of the lymphomas.

Pathology of the lymphomas.


Alexander Jeremiah Orenstein.

Alexander Jeremiah Orenstein.


RNA synthesis stimulating activity of ascorbate in Escherichia coli.


The results of operative treatment for recurrent dislocation of the gleno-humeral joint.


Spina bifida and myelomeningocele.

Spina bifida and myelomeningocele.


Renal allografting in the patient with juvenile diabetes mellitus.


Analysis of local anatomic factors that influence the survival times of pure epidermal and full-thickness skin homografts in guinea pigs.


Use of a dye-dilution technic to demonstrate biliary calculi in the operative cholangiogram.


A rainbow is for those who see. Twenty-second John Stanley Coulter Memorial Lecture.


Persistent glomerular changes after acute glomerulonephritis: a histometrical study of 34 autopsy cases.


N-((9- -D-ribofuranosylpurin-6-yl)-N-methylcarbamoyl) threonine, a modified nucleoside isolated from Escherichia coli threonine transfer ribonucleic acid.


Effect of methanol on the partial reactions of polypeptide chain elongation.


Transmission of Salmonella typhimurium in battery-reared chicks.


Structure of immunoglobulin A. II. Sequence around the hinge region and labile disulfide bonds of an immunoglobulin A2 myeloma protein.


Importance to "airsac" disease of water supplies contaminated with pathogenic Escherichia coli.


Chain folding in ribonuclease A derivatives lacking five and six carboxyl-terminal residues.


Purification of cysteine transfer ribonucleic acid of baker's yeast.


Preparation of highly purified ribonucleic acid polymerase; separation from polynucleotide phosphorylase and polyphosphate kinase.


Indirect fluorescent antibody technique for the detection of avian encephalomyelitis antibody in chickens.


A survey of the so-called "anatipestifer syndrome".


Interaction of Escherichia coli and Eimeria brunetti in chickens.


Conformational changes of transfer ribonucleic acid. Equilibrium phase diagrams.


Conformational changes of transfer ribonucleic acid. Comparison of the early melting transition of two tyrosine-specific transfer ribonucleic acids.


Mycoplasma meleagridis in Guatemalan turkeys.


Conformational changes of transfer ribonucleic acid. Relaxation kinetics of the early melting transition of methionine transfer ribonucleic acid (Escherichia coli).


Extracorporeal irradiation of blood with a 250 kV x-ray apparatus.


Metabolism of guanosine tetraphosphate in Escherichia coli.


Visualization of RNA synthesis on chromosomes.


Galactose transport in Escherichia coli and the galactose-binding protein.


Laser microbeams for partial cell irradiation.


Freeze-etching of bacteria.

Freeze-etching of bacteria.


Cell disjunction ("mitosis") in somatic cell reproduction.


The cytophysiology of mammalian adipose cells.


Neuronal microtubules, neurofilaments, and microfilaments.


Gas chromatography of the fat-soluble vitamins: a review.


Periodicity of sexual desire in relation to time of ovulation in women.


New bacteriophages for lysotyping Sh. boydii strains.


The inhibition effect of imidane on the incorporation of  14 C-glutamic acid-phenylalanine and  14 C-adenine into proteins and nucleic acids in Escherichia coli B.


Commemorating the 70th birthday of Professor Dr. Jaroslav Teisinger, Dr. Sc.


Comparative study of the morphology of the Czechoslovak and Danish BCG vaccine strain.


A comparative study of the efficacy of some immunological methods of diagnosis of typhoid fever and carriers. 2. The application of the reaction of indirect haemagglutination inhibition and the immunofluorescent method for the diagnosis of typhoid fever and carriers S. typhi.


Isotope-dilution analysis of cell stimulation or inhibition by biological media.


A modified antigen--antibody crossed electrophoresis characterizing the specificity and titre of human precipiting against Candida albicans.


Quantitative radioisotopic angiocardiography.


Radionuclides in renal transplantation.

Radionuclides in renal transplantation.


The effects of 2,6-bis(diethanolamino)-4-piperidino-pyrimido(5,4-D)pyrimidine (RA233) on the coronary circulation of the acutely transplanted dog heart: comparison with dipyridamole and adenosine.


Phases of the inflammatory response to subcutaneous implantation of a cotton pellet and their modification by certain anti-inflammatory agents.


Studies on phagocytosis. II. The effect of nonsteroidal anti-inflammatory drugs on phagocytosis and on urate crystal-induced canine joint inflammation.


The influence of acidosis on the chronotropic effects of tyramine in guinea-pig atria: relation to tyramine uptake and metabolism.


Fast estimation of the dilution curve area by a procedure based on a compartmental hypothesis.


The systems should accommodate one another.


Intercellular transfer by phage receptor site lipopolysaccharide.


Candidal granuloma: report of a case.

Candidal granuloma: report of a case.


An improved rat headclamp for neurosurgery or electrode implantation.


Effects of amygdaloid lesions on reversal learning in the deermouse.


Infantile gastro-enteritis--a preventable disease.


Epoxy film separable from glass surfaces for selective light and electron microscopy of tissue and in situ grown cells.


Studies on platelets and fibrin during rejection of canine renal allografts.


Polyethylene glycol distearate 600 with 10 per cent 1-hexadecanol; a superior embedding wax for warm climates.


Agar gel as a support for mammalian preimplantation eggs to be embedded in paraffin.


Salvage of paraffin-embedded material for use in scanning electron microscopy.


Preparation of epidermal peels from leaves of gymnosperms by treatment with hot, 60 per cent HNO 3.


A note on the foot and the body wall of the land snail, Cryptozona semirugata (Beck 1837).


Morphological studies of transcription.

Morphological studies of transcription.


The basic proteins of trout testis chromatin: aspects of their synthesis, post-synthetic modifications and binding to DNA.


Methods for studying protein-nucleic acid interaction.


Structural and functional properties of three mammalian nuclear DNA-dependent RNA polymerases.


Functional studies on chromatin.

Functional studies on chromatin.


Isolation and composition of nuclei and nucleoli.


Association behaviour of the oestradiol-binding protein complex with the nuclear fraction.


The structure of eukaryote chromatin.

The structure of eukaryote chromatin.


Use of indicator dilution techniques to determine patency of internal mammary artery implants.


The medical treatment of angina pectoris. II. Design of an antianginal drug study.


A parapraxis of Freud's in relation to Karl Abraham.


Discussion of Leonard Shengold's paper.

Discussion of Leonard Shengold's paper.


Leonardo and Dante.

Leonardo and Dante.


Three computer diagnosis methods compared.


The depressive personality. A critical review.


Isolation and identification of 5-methylthioribose from Escherichia coli B.


Recent advances in the pharmacology of peristalsis.


Fenticlor combined with triamcinolone acetonide in the treatment of infected dermatoses.


Indirect nervous mechanism in some effects of bradykinin.


A comparison of sustained-release prednisolone disodium phosphate with prednisolone in the treatment of reversible bronchospasm.


Double-blind clinical comparisons of topical betamethasone valerate and betamethasone benzoate in the treatment of steroid-responsive dermatoses.


Splenectomy in the management of Hodgkin's disease.


Arbovirus diseases.

Arbovirus diseases.


Recent trends in leprosy research.

Recent trends in leprosy research.


Advances in malariology relating to control and eradication.


Leishmaniasis in the Old World.

Leishmaniasis in the Old World.


Changing patterns of disease in the tropics.


Leishmaniasis of the New World: taxonomic problems.


Epidemiology and control of schistosomiasis.


Onchocerciasis.

Onchocerciasis.


Heart disease in the tropics.

Heart disease in the tropics.


Tropical sprue.

Tropical sprue.


Recent work on anaemias in the tropics.

Recent work on anaemias in the tropics.


Inhibition of DNA polymerase of E. coli by proflavine.


Midrid for migraine?

Midrid for migraine?


Direct attachment of orthodontic brackets to teeth using a plycarboxylate cement--a clinical report.


Peer review.

Peer review.


An orthodontic case--unilateral expansion treatment.


Dental plaque: its structure and prevention.


The effect of age on extraction wound healing in Syrian hamsters.


Personalized nutrition counseling.

Personalized nutrition counseling.


Restoration of fractured incisal angles with an ultraviolet activated sealant and a composite resin. A case report.


Changing responsibilties of the practitioner in community health.


Aboard the S.S. HOPE.

Aboard the S.S. HOPE.


Still more mutant tyrosine transfer ribonucleic acids.


DNA synthesis in nucleotide-permeable Escherichia coli cells. V. Structure of newly synthesized phiX174 replicative form DNA.


DNA synthesis in nucleotide-permeable Escherichia coli cells. IV. Mode of phiX174 replicative form DNA synthesis and the template involved.


Aminoacyl-transfer RNA binding to active 30 s subunits: effect of 50 s subunits and a new role for elongation factor T.


A temperature-sensitive mutation in Escherichia coli transfer RNA.


Hybrid T4 r II B cistrons created by genetic duplications.


Preventive complete denture prosthetics.


lac Repressor-operator interaction. VI. The natural inducer of the lac operon.


Removable orthodontic appliances in general practice.


Comparative study of three coating agents and their influence on bond strength of porcelain-fused-to-gold alloys.


Technique for making complete maxillary immediate denture impressions.


An intercistronic region in the histidine operon of Salmonella typhimurium.


Fabrication of an occlusal splint.

Fabrication of an occlusal splint.


Asymmetric replication and cellular differentiation.


Environmental health and animal wastes.

Environmental health and animal wastes.


Differentiation in vitro of mouse embryos beyond the implantation stage.


Visual perception of accelerated nitrogen nuclei interacting with the human retina.


Dimerization of proflavin by the laser raman temperature-jump method.


Intermolecular organization of deoxygenated sickle haemoglobin determined by x-ray diffraction.


Stereochemical and vibrational theories of odour.


A technique for studying sperm maturation in vitro.


Culture of cells from the urine of newborn children.


Dorothea Dix: Victorian militant.

Dorothea Dix: Victorian militant.


Effect of sodium nitrilotriacetate on toxicity, teratogenecity, and tissue distribution of cadmium.


In memoriam: Asher Winkelstein, M.D. 1893-1972.


Reminiscences of fifty years in cardiology at Mount Sinai with special reference to the two-step test.


Initiation factor 2-dependent ribosomal binding of N-formylmethionyl-transfer RNA without added guanosine triphosphate. Evidence is presented that suggests that GTP (or 5'-guanylylmethylene diphosphonate) is not essential for either formation of an AUG-directed, initiation factor IF-2-dependent initiation complex on the 30S subunit or for positioning of fMet-tRNA on the peptidyl site. However, recycling of limiting amounts of IF-2 requires both GTP and the 50S subunit. The formation of the complex IF-2-30S as an intermediate in polypeptidechain initiation is suggested.


Structure of inserted bacteriophage Mu-1 DNA and physical mapping of bacterial genes by Mu-1 DNA insertion. It is shown, by electron microscope observation of the structures of heteroduplexes, that Mu-1 DNA inserted into the bacterial episomes Flac and F(8)[1] is collinear with, rather than a circulation permutation of, the DNA of the mature Mu-1 bacteriophage. Observation of the position of the inserted Mu defines a point within the gene that has been inactivated (the lacI gene for Flac and a transfer gene in F(8)[1] in these particular instances). These examples illustrate a new, general method for physical gene mapping. The episome with Mu DNA inserted into F(8)[1] [i.e., F(8)[1](Mu)], although derived from a single colony, is heterogeneous in that a self-renatured sample shows a nonhomology loop of length 3.0 kb. This nonhomology loop, which has previously been observed in mature Mu-1 DNA, is due to an inversion.


Bidirectional replication of the chromosome in Escherichia coli. E. coli cells initiating chromosome replication after release from amino-acid starvation were incubated in [(3)H]thymine of moderate specific activity, followed by incubation in [(3)H]thymine plus [(3)H]thymidine of very high specific activity. The grain tracks produced in autoradiographs of chromosomes were denser on both ends than in the middle. The autoradiographic patterns are, therefore, evidence that replication of the chromosome in E. coli is bidirectional.


Curing of a killer factor in Saccharomyces cerevisiae. Many standard laboratory stocks of yeast are able to kill other yeast strains. This property has not been generally recognized because killing is observed only at low pH and not at the pH of standard media. In all strains examined, the genetic determinant for the killer trait shows non-Mendelian inheritance. The segregation patterns of our killer strains indicate that this killer determinant may be different from the killer previously described. Treatment of a killer strain with cycloheximide, but not with ethidium bromide, converts it into a sensitive nonkiller.


Transcription in yeast: a factor that stimulates yeast RNA polymerases. Yeast cells contain an RNA polymerase factor, pi, which is a heat-stable protein with an apparent molecular weight of 12,000. This factor stimulates transcription of calf-thymus, salmon-sperm, yeast-nuclear, and T4-phage DNA. It stimulates transcription by each of the four yeast-nuclear RNA polymerases, by rat-liver RNA polymerases I and II, and by Escherichia coli RNA polymerase. pi-Factor can cause each of the eukaryotic RNA polymerases to become insensitive to rifamycin AF-013, but does not stop inhibition of E. coli RNA polymerase by rifamycin AF-013. Stimulation of transcription by pi-factor is general, and does not apply only to a limited class of genes. Apparently, pi-factor stimulates transcription by increasing the proportion of RNA polymerase binding events that leads to the initiation of RNA chains.


A new element in the control of DNA initiation in Escherichia coli. When a thermosensitive mutant of E. coli affected in DNA initiation is heated to 41 degrees , a protein needed for DNA initiation is irreversibly denatured. When these bacteria are incubated at 30 degrees in the presence of several concentrations of chloramphenicol, DNA synthesis is greatly stimulated at a chloramphenicol, DNA synthesis is greatly stimulated at a chloramphenicol concentration of 2.5 mug/ml, and then sharply decreases. This stimulation of DNA synthesis appears to be caused by an increased frequency of initiation. The existence of an "anti-initiator" protein controlling the frequency of chromosomal initiation is proposed.


Nucleic acid hybridization with RNA immobilized on filter paper. RNA has been immobilized in a manner suitable for use in molecular hybridization experiments with dissolved RNA or DNA by a nonaqueous solid-phase reaction with carbonyldiimidazole and RNA "dry coated" on cellulose or, preferably, on previously activated phosphocellulose filters. Immobilization of RNA does not appear to alter its chemical character or cause it to acquire affinity for unspecific RNA or DNA. The versatility and efficiency of this method make it potentially attractive for use in routine analytical or preparative hybridization experiments, among other applications.


Role of nonhistone chromosomal proteins in the restriction of mitotic chromatin template activity. RNA synthesis virtually ceases during mitosis in eukaryotic cells. This phenomenon is explainable, at least in part, by the reduced template activity for RNA synthesis of mitotic chromatin. The restriction in template activity can be accounted for by the presence in the chromatin of mitotic-specific nonhistone proteins. Chromatin reconstituted by gradient dialysis from the pooled histones of S-phase and mitotic chromatin and the nonhistone proteins of mitotic chromatin had a template activity similar to that of native mitotic chromatin, and lower than native S-phase chromatin or chromatin reconstituted with the pooled histones and the S-phase and nonhistone proteins. The template activity was identical for chromatin reconstituted from the pooled nonhistone proteins and either the histones from S-phase or mitotic chromatin. These results are supported with data showing that the procedure of reconstitution produces a chromatin indistinguishable in its protein composition both qualitatively and quantitatively from its native counterpart.


A transcribing activity induced by satellite phage P4. Satellite bacteriophage P4 induces a new transcribing enzyme that synthesizes polyriboguanylic acid in the presence of the poly(dG).poly(dC) homopolymer pair. This transcribing activity was partially purified and shown to be distinct from the host RNA polymerase. Analysis of conditional lethal mutants suggests that this new enzyme is necessary for replication of phage DNA.


Endonucleolytic activity from Micrococcus luteus that acts on  -ray-induced damage in plasmid DNA of Escherichia coli minicells. A partially purified extract from Micrococcus luteus contains endonucleolytic activity toward ultraviolet (UV)-irradiated deoxyribonucleic acid (DNA). We found that the same extract also acts on superhelical, covalently-closed circular lambdadv DNA isolated from gamma-irradiated minicells of E. coli. The introduction of nicks in isolated covalently-closed circular DNA by an endonuclease in the extract results in relaxed circles, and these two circular DNA species are easily distinguishable by their sedimentation properties in alkaline sucrose. The frequency with which the endonuclease-susceptible lesions are produced in superhelical DNA is only marginally enhanced when (60)Co gamma-rays are administered to an aerobic rather than an anoxic minicell suspension. The ratio of endonuclease-sensitive defects to single-strand scissions, induced by gamma-irradiation in air, is about 1:3. The nuclease-sensitive lesions disappear from gamma-irradiated minicells during incubation after radiation presumably as a consequence of excision repair. Since the addition of UV-irradiated calf-thymus DNA depresses the ability of the M. luteus extract to attack not only UV-damaged E. coli DNA (a known substrate for the so-called UV-specific endonuclease that catalyzes the initial single-strand incision adjacent to the structural defect) but, also lambdadv DNA injured by gamma-rays, we conclude that physicochemical alterations induced by both types of radiation are recognized by one and the same endonuclease.


Reducing the number of inferior treatments in clinical trials. In clinical trials comparing two treatments, one would often like to control the probability of erroneous decision while minimizing not the total sample size but the number of patients given the inferior treatment. To do this obviously requires that one use a datadependent allocation rule for the two treatments rather than the conventional equal sample size scheme, whether fixed or sequential. We show here how this may be done in the case of deciding which of two normally distributed treatment effects has the greater mean, when the variances are assumed to be equal and known. Similar methods can be used under other hypotheses on the underlying probability distributions, and will provide a considerable increase in flexibility in the design of sequential clinical trials.


Recognition of nonsense codons in mammalian cells. The tritiated trinucleotide UGA was used in a binding assay to detect transfer RNAs that recognize this nonsense codon from calf-liver cells. Acylation of transfer RNA with labeled amino acids and determination of codon responses of aminoacyl-tRNAs demonstrate that a species of seryl-tRNA and a species of arginyl-tRNA recognize the codon UGA. Slight responses of cysteinyl-tRNA and of trytophanyl-tRNA to the codon UGA were also observed.


Elongation factor T-dependent hydrolysis of guanosine triphosphate resistant to thiostrepton. Methanol stimulates the hydrolysis of GTP catalyzed by bacterial ribosomes in the presence of the chain elongation factor T (EF-T). The methanol-stimulated activity is uncoupled from aminoacyl-tRNA binding to the ribosomes and does not require the presence of either synthetic polynucleotide messenger or aminoacyl-tRNA. When these reactants are present, along with EF-T, GTP, and methanol, the ribosomal binding of aminoacyl-tRNA is inhibited by thiostrepton but the uncoupled, EF-T-dependent hydrolysis of GTP is resistant to the antibiotic.


Is there a discriminator site in transfer RNA? We determined the nature of the fourth nucleotide from the 3'-end of several Escherichia coli tRNAs, and tabulated these results with the same data for all known tRNA sequences. We find a striking constancy of the fourth nucleotide in tRNAs specific for a given amino acid. Furthermore, tRNAs specific for chemically related amino acids are very likely to have the same nucleotide at the fourth position. One possible explanation for these regularities is the "discriminator" hypothesis: The code by which tRNA is recognized by its cognate aminoacyl-tRNA synthetase is logically hierarchical, with the fourth nucleotide serving as a primary "discriminator" site to subdivide the tRNAs into groups for recognition purposes. Each such group could have its own recognition code, or could be further subdivided by a secondary discriminator site. According to this hypothesis, chemically similar amino acids have the same discriminator nucleotide because they evolved from a single set of related amino acids indistinguishable to a primitive system. There are other possible explanations for the observed regularities at the fourth nucleotide. For example, it is conceivable that the position is used for a direct physical interaction with the amino acid in the charging process, and chemically similar amino acids naturally select the same nucleotide. Further experiments can be expected to clarify this question.


Historical aspects of some surgical training programs: a plea to retain the surgical generalist in the academic arena.


Studies in prolonged liver preservation.


Pulmonary intravascular and extravascular volumes in hemorrhagic shock and fluid replacement.


Comparative analysis of perfusion and nonperfusion methods for renal preservation.


Activation of B lymphocytes by concanavalin A in the presence of humoral factors released by T cells.


Thymus dependency of rosette-forming cells: evidence for a circulating thymic hormone.


Cell-mediated immunity and blocking antibodies to renal allografts.


Renal transplant survival, the HL-A system, and antilymphocyte serum therapy: report of some data collected for a recent conference.


Relationship between tolerance and facilitation of allografted cells.


Steroid sex hormones in the rat brain: specificity of uptake and physiological effects.


Androgenization and pituitary FSH regulation.


Sex difference in hypothalamo-hypophysial function.


Steroid hormones and brain function: progress, principles, and problems.


Biochemical studies of corticosterone binding to cell nuclei and cytoplasmic macromolecules in specific regions of the rat brain.


The role of steroid hormones in the control of gonadotropin secretion in adult female mammals.


Feedback mechanisms and the control of the hypothalamohypophysial complex.


Sex and brain-pituitary function at puberty.


Economic evaluation of anthelmintics under commercial feedlot conditions.


Kiel bone in the surgical treatment of tibial condylar fractures.


Amputations with and without myoplasty on rabbits with special reference to the vascularization.


H.A. Weijers in memoriam.

H.A. Weijers in memoriam.


Faecal and periurethral flora after oral administration of sulphonamide, nitrofurantoin and nalidixic acid.


Chronic respiratory paralysis. A clinical study of 12 patients in long-term respirator treatment after poliomyelitis.


Vitality of chondrocytes in the mandibular condyle as revealed by collagen formation. An autoradiographic study with  3 H-Proline.


Comparative trial of HPV-77, DE-5 and RA 27-3 live-attenuated rubella vaccines.


Treatment of acute diarrhea in outpatients. Double-blind study comparing ampicillin and placebo.


A simplified colorimetric method for serum isocitrate dehydrogenase.


Effect of hemolysis on the partial thromboplastin time.


Animal model for human disease. Spina bifida, sacral dysgenesis and myelocele. Animal model: Manx cats.


Induction of the generalized Shwartzman reaction in pregnant and nonpregnant rats by colchicine. The intravenous injection of colchicine (2 mg/kg body weight) into pregnant rats on the last 4 to 5 days of gestation induced disseminated intravascular coagulation, occluding glomerular capillaries with fibrin thrombi, typical of the generalized Shwartzman reaction. Thrombi did not form earlier than 9 hours after the injection of colchicine, whereas in the endotoxin-induced generalized Shwartzman reaction, thrombi were already observed 2(1/2) hours after the injection of endotoxin. The colchicine-induced generalized Shwartzman reaction could also be produced in hysterectomized "pregnant" rats. A single injection of colchicine into nonpregnant rats did not induce disseminated intravascular coagulation. If, however, fibrinolysis was inhibited with epsilon-aminocaproic acid, the colchicine-induced generalized Shwartzman reaction could also be elicited in nonpregnant rats. In this regard fibrinolysis inhibition represents one mechanism by which pregnancy prepares for the generalized Shwartzman reaction.


Cytolysis induced by human lymphotoxin.

Cytolysis induced by human lymphotoxin. By phase-contrast cinemicroscopy, highly purified human lymphotoxin induced two forms of cytolysis-one characterized by slow (1 to 2 hours) swelling (ballooning-type) and the other by sudden (3 to 5 minutes) shrinkage of the cell body and violent agitation of residual debris (popcorn-type). Specifically sensitized lymphocytes likewise caused both forms of lysis, morphologically indistinguishable from lymphotoxin-induced cytolysis. Lymphotoxin also inhibited cell division; mitoses diminished and virtually ceased before the onset of cytolysis. Many of the ultrastructural features preceding early lysis were similar to those associated with failure of osmoregulatory mechanisms-ie, condensation of mitochondria, dilation of rough-surfaced endoplasmic reticulum, separation of polysomes into individual units and expansion of the cell sap. After exposure to lymphotoxin for 12 hours or more, most remaining cells exhibited these same ultrastructural changes but lacked striking mitochondrial lesions.


Animal model of human disease: Kuru, Creutzfeldt-Jakob disease (slow virus infections). Animal model: transmissible mink encephalopathy, scrapie-like disease of mink.


Presentation of the gold headed cane to Sidney Farber.


Relationships between oleic acid uptake and lipid metabolism in Mycobacterium smegmatis.


Morphologic study of the participation of the complement system in hyperacute rejection of renal xenotransplants. The role of polymorphonuclear leukocyte (PMN) and platelet infiltration in the hyperacute rejection of renal xenotransplants was studied. In a first group, a dog kidney was grafted to rabbit recipients with intact immune adherence and chemotaxis. A second group included recipients depleted of PMN's with nitrogen mustard, and in a third group, immune adherence and chemotaxis were modified by depleting the third component of complement by means of cobra venom factor. Serial kidney biopsies were studied with light and electron microscopic technics. A semiquantitative evaluation of PMN and platelet glomerular infiltration indicated that a reduction in the number of PMN's or platelets is associated with an increased survival time of the transplanted kidney.


Ion filtration chromatography: a powerful new technique for enzyme purification applied to E. coli alkaline phosphatase.


Automatic measurement of interference photographs from the ultracentrifuge.


Estimation of radioactivity in electrophoresis gels by a scanning semiconductographic procedure.


A simple and sensitive method for detection of L-asparaginase by polyacrylamide gel electrophoresis.


Quantitative assay of the binding of small molecules to protein: comparison of dialysis and membrane filter assays.


Turnover of intracellular proteins.

Turnover of intracellular proteins.


Production of volatile sulfur compounds by microorganisms.


Rifamycins: a general view.

Rifamycins: a general view.


Ferredoxins and flavodoxins of bacteria.


Training a microbiologist.

Training a microbiologist.


Microbial carotenoids.

Microbial carotenoids.


Genetics of the Proteus group.

Genetics of the Proteus group.


Carcinogens produced by fungi.

Carcinogens produced by fungi.


Regulation of chromosome replication and the bacterial cell cycle.


Inorganic nutrition.

Inorganic nutrition.


The genus Erwinia: enterobacteria pathogenic to plants and animals.


The microbe as a source of food.

The microbe as a source of food.


RNA virus gene expression and its control.


Pathogenicity of the L-phase of bacteria.


Rifampin: a semisynthetic derivative of rifamycin--a prototype for the future.


A randomized clinical trial of daunorubicin and a combination of prednisone, vincristine, 6-mercaptopurine, and methotrexate in adult acute nonlymphocytic leukemia.


Light and electron microscopic studies of tumors induced by small plaque variant of chicken embryo lethal orphan virus.


Inhibition of tumor growth and survival of aged mice inoculated with Moloney tumor transplants and treated with endotoxin.


Relative rates of protein synthesis and reaggregation in embryonic chick liver cells cultured in defined and supplemented media.


1972 census of ultraclean hospital facilities in U.S.


Large scale culturing of normal diploid cells on glass beads using a novel type of culture vessel.


Passage of cellular structures through millipore filters. Light-microscopic, electronmicroscopic and immunofluorescence studies.


Stimulation of jejunal secretion by a crude Escherichia coli enterotixin.


Diarrhea: a current view of the pathophysiology.


The role of sucrose and other sugars in the development of dental caries; a review.


Current concepts concerning the development of dental caries.


The effect of vasodilating drugs in peripheral vascular disease.


Traumatic occlusion as a factor in the propagation of periodontal disease.


Effect of the physical consistency of food on the 'crevicular complex' and the salivary glands.


Need associations of narcotic addicts.

Need associations of narcotic addicts.


Quantification of two projective tests for deaf clients.


A second look at sources of clinical research.


Stress and disease.

Stress and disease.


Neural control of puberty.

Neural control of puberty.


Premenstrual tension and "psychogenic" amenorrhoea: psycho-physical interactions.


The osseous system. An overview.

The osseous system. An overview.


Chromosome mobilization and integration of F-factors in the chromosome of RecA strains of E. coli under the influence of bacteriophage Mu-1.


Mitotic non-conformity in Aspergillus nidulans: the effects of caffeine.


The cardiovascular system.

The cardiovascular system.


Cell division and the production of cells lacking nuclear bodies in a mutant of Salmonella typhimurium.


Genetics and biochemistry of cycloheximide resistance in Physarum polycephalum.


Free tryptophan in plasma and brain tryptophan metabolism.


Milk proteins.

Milk proteins.


Receptor site for sour stimuli.

Receptor site for sour stimuli.


Heterologous reinnervation of the iris from sympathetic ganglia in organ culture.


"Dished faces", brain size and early hominids.


Measuring gas in blood.

Measuring gas in blood.


Dr. P. H. Leslie.

Dr. P. H. Leslie.


Electronic processes and photosensitization in bilayer lipid membranes.


Selective partial denervation by alcohol injections and their results in spasticity.


Adjuvant effect of bendrofluazide on propranolol in hypertension.


The itching patient. A review of the causes of pruritus.


Anti-N-like antibodies in the sera of patients undergoing chronic hemodialysis.


Excystation of Hymenolepis microstoma. I. Influence of age, population density and pre-treatment of the cysticercoids.


48-hour preservation of pig kidneys using continuous hypothermic plasma perfusion. Effect and complications.


Potential sources of cadaveric kidneys for transplantation in a general hospital.


Lymphocyte transformation tests before, during and after extracorporeal irradiation of the blood.


Gamma heavy chain disease. Reports of three patients.


Treatment of hereditary angioneurotic oedema with tranexamic acid. A random double-blind cross-over study.


Lionel Sharples Penrose.

Lionel Sharples Penrose.


Isolation of high molecular weight DNA from yeast nuclei.


Simple apparatus for pulverization and rapid quantitative transfer of frozen tissue.


Infrared gas analyzer for Warburg-type CO 2  measurements in yeast with a computer program appendix.


Simple rapid procedures for isolation of tobacco leaf nuclei.


Early ego integration and object relations.


Physiological and enzymatic aspects of histidine-mediated control of the tryptophan pathway.


Gel electrophoresis of the cell envelope of a division muant of Escherichia coli.


Bacteriolytic and bactericidal activity of maternal and cord sera. Relationship to complement, lysozyme, transferrin, and immunoglobulin levels.


Complete heart block complicating bacterial endocarditis.


Rheumatoid disease, laboratory data.

Rheumatoid disease, laboratory data.


Comparative observations on AChE distribution in pancreas of some amphibians, repitiles and birds, with special reference to the islets of langerhans.


On some improvements in the preparation of high-resolution radioautographs by the flat substrate method.


Experimental test of the contingency model of leadership effectiveness.


The use of bone autografts in canine orthopaedic surgery.


Fixation of rat lungs under physiologically defined conditions.


Diagnosis and treatment of inherited bleeding disorders.


Henoch-Schoenlein syndrome.

Henoch-Schoenlein syndrome.


Hematologic manifestations of systemic disease.


Hematologic effects of cardiac disease.

Hematologic effects of cardiac disease.


Iron deficiency in children.

Iron deficiency in children.


Hemoglobinopathies of clinical importance.


Eosinophilia in children.

Eosinophilia in children.


Disorders of leukocytes leading to recurrent infection.


Disorders of bone marrow production.

Disorders of bone marrow production.


Carotenoid vitamin A precursors and analogs in foods and feeds.


Situational variables and performance on Machover's figure-drawing test.


Differential perception of Kinget's drawing-completion stimuli.


Inhibition and the human movement response in children.


The Holtzman Inkblot Technique: a bibliography, 1956-1970.


Streptokinase-streptodornase in the treatment of minor injuries.


Trial of a new broad-spectrum penicillin (amoxycillin) in general practice.


A psychotropic agent in the climacteric.


Quantitative explorations in the history of psychology in Yugoslavia: translations.


"Spontaneous" improvement in the social positions of emotionally disturbed children in regular classes.


Mural group: integration of projective drawings with standard verbal group therapy techniques.


Lobeline and reduction of cigarette smoking.


Perception and discrimination as a function of stimulus orientation: the "oblique effect" in man and animals.


Findings from family planning research.

Findings from family planning research.


Diphenylhydantoin and phenobarbital in the relief of psychoneurotic symptoms. A controlled comparison.


Overview of the skill learning process.

Overview of the skill learning process.


Pathogenesis of mycoplasmal pneumonia in swine.


Adsorption of chicken erythrocytes by monkey kidney control cell cultures: scanning and transmittance electron microscopy.


A selective medium for the isolation of Sphaerophorus necrophorus.


Fluorescent antibody technique for identifying isolates of Sphaerophorus necrophorus of bovine hepatic abscess origin.


Obesity: a serious symptom.

Obesity: a serious symptom.


Correction of contour defects of the face with dermal and dermal-fat grafts.


Hyperglycemic nonketotic coma after liver transplantation.


The first E.R. Magnus Oration--February 17, 1971.


By dentistry out of surgery--the birth of a specialty.


The veterinarian and intensive livestock production: humane considerations.


Medical administration and medical research in developing countries: remarks on their history in colonial East Africa.


Hypochondriasis of the eighteenth century--neurosis of the present century.


Revised structure of aspartokinase I-homoserine dehydrogenase I of Escherichia coli K12. Evidence for four identical subunits.


The threonine-sensitive homoserine dehydrogenase and aspartokinase activities of Escherichia coli K12. The two catalytic activities are carried by two independent regions of the polypeptide chain.


Fluorescence studies on substrate binding to seryl-tRNA synthetase from yeast.


Biological activity of cross-linked Escherichia coli tRNA f Met.


Properties of Q -replicase protein synthesized in a cell-free system.


The release of ribonucleic acid from the membranes of relaxed Escherichia coli cells starved for amino acids.


The lost half-century in English medicine, 1700-1750.


Henry L. Coit and the certified milk movement in the development of modern pediatrics.


Clinical biostatistics. 18. The clofibrate trials: another dispute about contratrophic therapy.


The United States Pharmacopeia of 1820 and its background.


A study of extraction columns for aqueous polymer two-phase systems.


Animal models for research in leprosy.

Animal models for research in leprosy.


Net and unidirectional transmucosal flux of sodium and water in acute human diarrheal disease.


Tom Douglas Spies--a biographical sketch (1902-1960).


Role of the cecum in maintaing   5 -steroid- and fatty acid-reducing activity of the rat intestinal microflora.


Endotoxin determinations in gingival inflammation.


Unidentified factor activities in whole soybeans required for optimum growth of Coturnix quail.


Surface characteristics of teeth following periodontal instrumentation: a scanning electron microscope study.


History of the Royal Naval Hospital, Plymouth. I. The life and times of Captain Richard Creyke.


Lymphoma of the female urethra masquerading as a caruncle.


Gangrene of the penis following cavernospongiosum shunt in a case of priapism.


Unusual malignant tumors of the scrotum: review of 5 cases.


Experience with Kaufman's operation for correction of post-prostatectomy urinary incontinence (sagging urogenital diaphragm--a theory for the cause of incontinence).


Simplified office bacteriology: a method of urine culture and sensitivity testing.


Urinary prognosis in spina bifida.

Urinary prognosis in spina bifida.


Studies in health and disease over a span of 26 years: a story of ideas and their dependence on the environment.


The presentation of a portrait of Dr. Hugh J. Jewett.


The altered metabolism of the full thickness skin graft.


The nitrogen fixation genes.

The nitrogen fixation genes.


Specification of gradients used for studies of chemotaxis.


Chemotaxis in Escherichia coli analysed by three-dimensional tracking.


Further studies on consecutive matings in the Anopheles gambiae complex.


Does X chromosome inactivation occur during mitosis of first cleavage?


Fusion of frog and tadpole erythrocytes.


Oral transmission of Brugia pahangi to Jirds (Meriones unguiculatus).


Increased plasma enzyme concentrations in rats with functional ischaemia of muscle provide a possible model of Duchenne muscular dystrophy.


Immune status of patients with multiple sclerosis. Analysis of primary and established immune responses in 24 patients.


UV-induced recombination and repair of parental lambda bacteriophages labeled by means of host-controlled modification.


A promoter site and polarity gradients in phage S13.


Recombination of parental lambda phages labeled by means of host-controlled modification.


rna synthesis in t4 infected Escherichia coli during amino acid starvation.


Methylation of bacteriophage P1 DNA.

Methylation of bacteriophage P1 DNA.


A mutation of T4B phage, which enhances suppression of ligase mutants with rII mutations.


Tobacco mosaic virus multiplication and expression of the N gene in necrotic responding tobacco varieties.


Molecular repair, wound healing, and carcinogenesis: tumor production a possible overhealing?


1,3-bis(2-chloroethyl)-1-nitrosourea (bcnu) and other nitrosoureas in cancer treatment: a review.


Scanning electron microscopic studies on rabbit's spinal cord by resin cracking method.


Cavernous angiomas of the tympanic membrane.


Otoplasty.

Otoplasty.


Mucormycosis in a patient receiving azathioprine.


Anesthesiology 1970.

Anesthesiology 1970.


The Mondini type of cochlear malformation. A survey of the literature.


Hemilateral rhinotomy in the treatment of hereditary hemorrhagic telangiectasia.


Rhytidectomy in men. A new approach.

Rhytidectomy in men. A new approach.


Acquired atresia of the external auditory canal.


The critical evaluation of thromboplastin.


The use of expiratory forced flows for determining response to bronchodilator therapy.


A method of augmenting coronary perfusion during internal cardiac massage.


Air-fluid levels in the left lower thorax following a fall.


Large scale purification of tRNA ser , tRNA tyr  and tRNA phe  from Baker's yeast.


The level and sub-cellular distribution of  -aminolaevulinate synthase activity in semi-anaerobic and aerobic yeast.


Simple smear method for the sampling and culturing of embryonal and fetal tissues.


Association of ribonuclease I with ribosomes and their subunits.


Studies on the role of an Escherichia coli 50 S ribosomal component in polypeptide chain elongation.


Partial monosomies 18. Review of cytogenetical and phenotypical variants.


Studies on the formation of transfer ribonucleic acid-ribosome complexes. 23. Chloramphenicol, aminoacyl-oligonucleotides, and Escherichia coli ribosomes.


Studies on the formation of transfer ribonucleic acid-ribosome complexes. XXII. Binding of aminoacyl-oligonucleotides to ribosomes.


Studies on polypeptide elongation factors from Escherichia coli. II. Purification of factors Tu-guanosine diphosphate, Ts, and Tu-Ts, and crystallization of Tu-guanosine diphosphate and Tu-Ts.


Kinetics and mechanism of the binding of pyridoxal 5'-phosphate to apoglutamate decarboxylase. Evidence for a rate-determining conformation change.


The comprehensive care of patients with spina bifida.


Haloperidol, clopenthixol, and chlorpromazine in chronic schizophrenia.


Special award to C. Gordon Zubrod, MD, Director, Division of Cancer Treatment, National Cancer Institute, Bethesda, Md.


Politicalization of the cellular estate.


Surgery of the hand. 1.

Surgery of the hand. 1.


H. influenzae meningitis: therapeutic trials.


Caloric homeostasis and disorders of fuel transport.


Robert S. Schwab Laboratory.

Robert S. Schwab Laboratory.


Comparison and estimation of effect on caries of daily supervised toothbrushing with a dentifrice containing sodium fluoride and a dentifrice containing potassium fluoride and manganese chloride. A three-year clinical test.


A comparative study of oral vestibular sulcus reproduction.


Hemopoietin-initiated changes in differential retransplantability of mouse femoral marrow-derived colony-forming units (CFU).


The effect of pentobarbital (Nembutal) on prolactin release in the rat.


Immune adherence by the alternate complement pathway.


Effect of endotoxin on phosphoenolpyruvate carboxykinase activity in mouse liver.


Natural antibody to sheep erythrocytes in bursectomized chickens.