- Volume 14, Issue 1, 1956
Volume 14, Issue 1, 1956
- Article
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The Isolation and Chemical Nature of Capsular and Cell-wall Haptens in a Bacillus Species
More LessSUMMARY: By extracting the capsular material of Bacillus M with hot water, d-glutamic acid polypeptide and a polysaccharide were isolated. The polypeptide absorbs the antibody from an anthrax immune serum, which reveals a homogenously distributed capsular material in Bacillus M. The polysaccharide absorbs one of the homologous antibodies, which renders a characteristic structure visible in the capsule and gives a specific cell-wall reaction. By using lysozyme digestion for the dissolution of the capsule or of the cell-wall a mucoprotein was isolated. The mucoprotein gives serological reactions identical with those of the polysaccharide, and it corresponds to a less degraded form of the cellular substance participating in building up both the cell wall and the capsular structure.
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The Relation of Ribose Nucleic Acid to the Early Staǵes of Induced Enzyme Synthesis in Yeast
More LessSUMMARY: The synthesis of deoxyribonucleic acid (DNA) in yeast can be abolished by dosages of ultraviolet light (UV) which permit ribonucleic acid (RNA) and protein synthesis to continue. Those dosages of UV which inhibit α-glucosidase synthesis prevent not only the net utilization of the free amino acid pool but also inhibit glycine incorporation into proteins and decrease to a minimal value glycine and phosphate incorporation into RNA. The latent period before the appearance of α-glucosidase was characterized by an increased sensitivity to irradiation and certain amino acid analogues. The significance of these results in an interpretation of the early stages in enzyme induction is discussed.
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A Study of the Genetics of Penicillin-producing Capacity in Penicillium chrysogenum
More LessSUMMARY: Four non-penicillin-producing (p) strains were isolated from the strain 47.1564 Wis. of Penicillium chrysogenum and used in this work. Seven heterokaryons and seven heterozygous diploids were synthesized between the four p strains and one penicillin-producing (+) strain. All these strains were further marked by nutritional requirements and differences in colour of the conidia. None of the heterokaryons and diploids between non-producing strains produced any appreciable amount of penicillin; all the heterokaryons and diploids between a producing and a non-producing strain did produce penicillin in amounts of the same order as those of the producing strain. The four p mutations behave like alleles: p is recessive to the wild condition. Linkage of the allele p to y and to cy may be deduced from data of the somatic segregation from a heterozygous diploid.
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The Influence of Depletion of Nitroǵenous Reserves upon the Phenomenon of Induced Enzyme Biosynthesis in Cells of Escherichia coli
More LessSUMMARY: No β-galactosidase was formed when nitrogen-depleted cells of Escherichia coli 1433 were treated with lactose unless a source of nitrogen was added to the cells. In the presence of an exogenous nitrogen source there was an appreciable delay between the addition of lactose and the appearance of induced β-galactosidase activity. In contrast, induced increases of nitrate- and tetrathionate-reductase activities were developed without appreciable delay when depleted cells were treated with nitrate and tetrathionate, respectively, in the absence of additional nitrogen sources. The total amounts of the reductase activities developed in depleted cells were less than those obtained with non-depleted cells. The total amount of nitrate reductase activity formed was only slightly increased in the presence of ammonium sulphate, whereas normal degrees of activity were attained in the presence of casein hydrolysate. Ammonium sulphate markedly stimulated the formation of tetrathionate reductase activity.
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Tetrazolium Reduction as a Means of DifferentiatingA Streptococcus faecalis from Streptococcus faecium
More LessSUMMARY: Tetrazolium (2:3:5-triphenyltetrazolium chloride) was used in a glucose nutrient medium to show the considerable differences in reducing properties between some of the Lancefield group D streptococci. The ability to reduce tetrazolium to formazan, in a glucose-containing medium, at an initial pH 6·0, distinguishes strains of Streptococcus faecalis from those of S. faecium (Orla-Jensen) which for many years have been classified in the same species as S. faecalis. Differences in reducing properties correspond with many other tests now used to separate these species. Measurements of the oxidation-reduction potentials in growing cultures showed that S. faecalis produced an Eh value about 150 mV. lower than S. faecium. Confirmation of the differences in reducing properties of these species was obtained by testing 68 freshly isolated strains of S. faecium and 34 strains of S. faecalis.
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Turbidity Chanǵes in Bacterial Suspensions in relation to Osmotic Pressure
More LessSUMMARY: The turbidity of suspensions of various Gram-negative bacteria is affected by the tonicity of the suspending medium. The light extinction of the suspension increases in a nearly exponential fashion with the solute concentration and approaches a maximum at concentrations close to 0·15m-NaCl. The maximal optical response to tonicity changes varies widely in different bacterial species, ranging from 30 to 140 % increase in light extinction as compared with the turbidity of the suspension in distilled water. The turbidity changes seem to depend on the viability of the bacterial cells as they cannot be elicited in bacteria killed by various procedures. The influence of the described phenomenon on the determination of bacterial cell concentration by the customary turbidimetric methods is discussed and its application for the estimation of the number of viable cells is suggested.
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Turbidity Chanǵes in Bacterial Suspensions: Kinetics and Relation to Metabolic State
More LessSUMMARY: The kinetics of the turbidity changes in bacterial suspensions due to variations in the osmotic pressure of the medium were investigated. The time curve of the turbidity changes followed a monomolecular course, but the velocity constant was strongly dependent on the osmotic pressure. The value of the temperature coefficient (Q 10) of the reaction was close to two. The rapid adjustment of the turbidity (increase or decrease) to the changes in osmotic pressure of the medium was followed by a phase of slow decline in light extinction. In this slow phase the rate of turbidity decrease was independent of the prevailing osmotic pressure, but varied with the nature of the solute used; it was markedly accelerated by KCN or HgCl2. The effect of HgCl2 was annulled by thiol compounds. Certain substances affected the optical effect and the respiration in a parallel manner. The similarity between these observations and the findings of several authors with regard to turbidity changes in mito-chondrial suspensions is discussed.
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A Nuclear Gene Suppressor of a Cytoplasmically Inherited Character in Neurospora crassa
More LessSUMMARY: The cytoplasmically inherited trait in poky, Neurospora crassa, is recognized by certain defects in the cytochrome system accompanied by a low growth rate. In the presence of the gene, f, the growth rate of a poky strain becomes nearly normal but the defective cytochrome system remains unchanged, as if the defects were being compensated for by an increase in activity of some other enzyme system. When the f allele of this gene is replaced by its normal counterpart the poky character is again fully expressed. The allele, f, is apparently without effect on another cytoplasmically inherited character, mi 3, similar in its properties to poky. Nor do the nuclear gene mutants, C115 and C117, also similar in phenotype, appear to respond to f. A nuclear gene suppressor of the mutant, C115, restores to normal not only the growth rate but also the cytochrome system of this mutant. No effect of this suppressor on poky, mi 3 and C117 has been detected.
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An Immunological Study of the Constitutive and the Penicillin-induced Penicillinases of Bacillus cereus, Based on Specific Enzyme Neutralization by Antibody
More LessSUMMARY: Exocellular penicillinases from strains 569 and 5/B of Bacillus cereus gave almost identical activity-neutralization curves when titrated with antisera prepared against the enzyme from either strain; but were easily distinguishable by differences in their neutralization reaction with an anti-569 penicillinase serum previously partially absorbed with either the 5/B or the 569 enzyme. By contrast, no differences in neutralization reaction were detected between basal and induced penicillinase from strain 569 and the constitutive penicillinase from strain 569/H (a mutant derived from strain 569), when treated with samples of the anti-569 penicillinase serum, previously partially absorbed with each penicillinase preparation separately.
Strain 569 was not found to produce any substance in significant quantities capable of combining with anti-penicillinase neutralizing antibodies other than penicillinase itself.
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Invertase Formation in Saccharomyces fraǵilis
More LessSUMMARY: The formation of invertase in Saccharomyces fragilis was studied by the continuous culture technique. Invertase formation was markedly inhibited by glucose in the culture medium at concentrations greater than 0·001% (w/v), by galactose and lactose at all concentrations tested, and by several other carbon sources. The mean generation time of the organisms and the concentration of ammonia and growth factors had no significant effect on invertase formation. The pH value of the growth medium modified the amount of enzyme formed. The invertase activity, together with non-enzymic hydrolysis of sucrose by the acidic culture medium, was sufficient to account for the disappearance of the observed amount of sucrose from media containing sucrose.
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A Survey of Physically Active Organic Infusoricidal Compounds and their Soluble Derivatives with Special Reference to their Action on the Rumen Microbial System
More LessSummary: Many sparingly water-soluble neutral substances, including several indole derivatives, will quickly kill and often disintegrate washed living rumen ciliates at 35–39°, when acting at or near the saturation point (0·002–0·1 m) in a phosphate + acetate buffer at pH 7. The toxic compounds are mostly readily soluble in light petroleum. Organisms of the genera Isotricha, Dasytricha and Ophryoscolex, in particular, exhibit characteristic modes of disintegration when acted upon by such substances. Prominent among these are the terpene alcohols menthol, borneol and isoborneol, and their more soluble glucosides (both α- and β-) and their acid succinates. Menthoxyacetic acid is also similarly toxic. On the other hand, menthol and borneol β-glucuronides are not toxic to the rumen ciliates unless added to rumen contents containing bacteria also. Unlike menthol, borneol, in nearly saturated solution, is not particularly toxic to the rumen bacterial species Streptococcus bovis and Sarcina bakeri and quite high concentrations (0·1–0·4 %) of the terpenoid succinates and glucosides are required for even partial inhibition of the growth of true rumen saccharolytic bacteria under otherwise favourable conditions. The population of lipolytic (esterase producing) bacteria in rumen contents from a hay and dried grassfed sheep was of the order of 500,000/g. rumen contents. Bacillus licheniformis was the chief anaerobic lipolytic species isolated.
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The Production of Capsules, Hyaluronic Acid and Hyaluronidase by Group A and Group C Streptococci
More LessSummary: Some capsulated group A and group C streptococci were found to produce both hyaluronic acid and hyaluronidase during active growth; thus confirming and extending the work of Pike (1948 b). In a group C strain, LM, the free hyaluronic acid in liquid culture represents an excess of synthesis over destruction, the balance being influenced by the aeration of the culture. Within the limits examined the degree of aeration did not, however, influence hyaluronidase or hyaluronic acid production by strains producing either the enzyme or its substrate exclusively. A non-capsulated, hyaluronidase producing mutant of strain LM was isolated but capsulated cells, free from this variant, also produced the enzyme. Evidence is presented that the spreading activity of strain LM preparations in rabbit dermis is due to hyaluronidase rather than to capsular material as suggested by Pradhan (1937).
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The Isolation and Characterization of a Hyaluronidase Produced by a Capsulated Strain of Group C Streptococcus
More LessSummary: A hyaluronidase preparation was isolated by the methods of protein precipitation from the culture fluid of a capsulated group C streptococcus cultivated in a serum-free medium. The preparation was active in the mucin clot prevention and turbidimetric tests for hyaluronidase and rapidly destroyed the capsules of group A and group C streptococci. The enzyme resembled other streptococcal hyaluronidases in its reaction to pH changes but differed from these both in its thermolability and antigenic specificity.
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A Rapid Method for Determining the Proportion of Viable Bacteria in a Culture
More LessSummary: A method of making graticules on the surface of Cellophane is described. The proportion of viable bacteria in a culture can be estimated by inoculating a sample on to such a graticule, and counting the organisms before and after a short period of growth.
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The Nucleic Acids of Sarcina lutea
More LessSummary: The deoxypentosenucleic acid (DNA) and pentosenucleic acid (PNA) were isolated from Sarcina lutea and their purine and pyrimidine contents determined. No differences were detected in composition of either the DNA or the PNA isolated from cultures grown at different times. The composition of the DNA from a streptomycin-resistant strain did not differ significantly from that of DNA from a normal streptomycin-sensitive strain, but the composition of the PNA from the resistant strain did differ significantly from that of PNA from the sensitive strain. The DNA contained a very high proportion of guanine and cytosine to adenine and thymine. In the PNA from both streptomycin-sensitive and resistant strains, guanine and cytosine predominated and the ratio of guanine + uracil to adenine + cytosine was nearly 1.
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The Induction of Bacteriophage in Staphylococci
More LessSummary: The induction properties to ultraviolet light of some of the staphylococcal phages of the National Collection of Type Cultures (Colindale, London) and their propagating strains were studied. There was considerable variation in response, but in all cases phage titres rose. Bacterial opacity was an unsatisfactory indicator of induction and on some occasions no lysis was detected.
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The Induction of the Lytic Cycle in Lysogenic Bacteria by Phagolessin A 58
More LessSummary : Phagolessin A58, an antibiotic having antiphage activity, was found to have an action which induced the lytic cycle in some strains of lysogenic bacteria. Four different lysogenic organisms were tested : Bacillus megaterium 899 ; Escherichia coli FCb; E. coli Temple; E. coli Lampert. Two of the organisms were induced by phagolessin A58 and two were not. There appeared to be a relationship between the susceptibility of a given strain to induction by ultraviolet irradiation and to induction by phagolessin A58. The four different phages carried by the respective lysogenic strains were inactivated to a greater or lesser extent by phagolessin A 58, but there was no correlation between such sensitivity on the part of the carried phage and inducibility of the particular lysogenic strain. Serial transfers of the four lysogenic strains in broth containing phagolessin A58 were made in an attempt to produce non-lysogenic, phage-sensitive mutants. With only one organism, Baciltus megaterium 899, did this treatment result in the selection of such a mutant. Some of the chemical and biological properties of phagolessin A58 were
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The Occurrence of Chitinase in some Bacteria
More LessSummary: A method for the detection of small quantities of chitinase in culture fluids is described and the results of a survey of representative species of the main groups of bacteria presented. Chitinase is produced by some but not all of the soil and water bacteria. Chitinase appears to be a constitutive enzyme in many species of bacteria; its occurrence may prove of diagnostic value.
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The Classification and Nomenclature of Organisms of the Pleuropneumonia Group
More LessThe taxonomic status of the micro-organisms of the pleuropneumonia group has remained confused for many years. There is no generally accepted nomenclature or classification, although the need for these has been widely recognized and has become more urgent with the increasing number of new strains of pleuropneumonia-like organisms isolated. Recently Freundt (1955) and Edward (1955) made proposals for classifying and naming these organisms. Although published separately their proposals were in close agreement with each other, as a result of previous informal exchanges of views between the authors. However, it was felt that the publication of two separate papers, each of which provided lists of named species differing from each other only slightly, might cause confusion, particularly as both papers unfortunately contained a number of printing errors. Therefore, it was decided to prepare a joint paper. It is hoped that the proposals made will provide a basis for discussion among those interested in this group of organisms, and will lead to the adoption of a nomenclature which commands general agreement. It is also felt that the study of strains of pleuropneumonia-like organisms may be stimulated by the establishment of named species.
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Phage Typing of Salmonella typhimurium: its Place in Epidemiological and Epizootiological Investigations
More LessSummary: Two series of adapted phages were compared: the first consisted of phage preparations belonging to three different antigenic groups, the second series was antigenically homogeneous. The two typing schemes based on these phage preparations yielded entirely different groupings of the Salmonella typhimurium strains examined. Nevertheless, by each of the schemes it was possible to identify those strains which were related epidemiologically. These findings are compared with those obtained with Lilleengen’s series of selected anti-O phages, which are employed in Sweden. The place of phage typing in epidemiological and epizootiological investigations is discussed. It is concluded that it is unnecessary to attempt international standardization of the phage typing of S. typhimurium or of any other Salmonella species which cause food poisoning in man.
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