- Volume 12, Issue 2, 1955
Volume 12, Issue 2, 1955
- Article
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Non-motile Escherichia coli O55, B5 Strains
More LessSUMMARY: A description is given of twelve non-motile Escherichia coli O55, B5 strains isolated during an outbreak of diarrhoea. Possible uses of such strains in serological practice and in epidemiological investigations are indicated.
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The Metabolism of Sodium 2-Keto-d-gluconate by Micro -organisms
J. De Ley and J. VandammeSUMMARY: The ability of various bacteria, actinomycetes, yeasts and moulds to grow on a medium containing sodium 2-keto-d-gluconate as the major carbon source was investigated. The disappearance of 2-ketogluconate during growth was followed and the ability of washed unadapted cell suspensions to oxidize this substrate (as evidenced by O2 uptake) was studied. Adapted strains were examined for the presence of a 2-ketogluconokinase; this enzyme was detected in organisms of the genera Pseudomonas, Xanthomonas, Escherichia, Aerobacter, Paracolobactrum, Serratia, Erwinia, Bacillus. Although some bacteria and yeasts consumed 2-ketogluconate during growth and washed cells were able to oxidize it (after an induction period) 2-ketogluconokinase activity was not detected in cell-free extracts, prepared from these organisms, namely: species of Agrobacterium, Corynebacterium, Schwannio-myces, Debaryomyces, Lipomyces, Candida. Several moulds (chiefly Pyrenomycetes, Aspergillales and Fungi Imperfecti) displayed the same phenomena. A few strains grew weakly on the substrate; however, unadapted cells did not show uptake of oxygen. The remaining strains of bacteria, yeasts, moulds and all the actinomycetes were without activity on 2-ketogluconate.
The results in this paper substantiate the opinion that the ‘direct oxidation’ pathways of carbohydrate metabolism are very widespread and important among microorganisms.
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Properties of a Small Bacteriophage and the Action of some Compounds on it
More LessSUMMARY: Phage S13, a small phage active against a strain of Escherichia coli, had a latent period of 20 min. on this host. Intracellular phage multiplication was detected only toward the end of the latent period. Photo-reactivation of ultraviolet irradiated phage occurred, but the inactivated phage did not kill its host. More than 1600 compounds were tested for ability to prevent growth of phage S13 on E. coli at concentrations allowing growth of the bacterium, but only thirteen were active. Seven of these compounds were examined further; none affected free S13 phage or the adsorption of S13 phage to its host. The only compound investigated in detail, 4:4-bis-(2-dihydroglyoxalinyl) stilbene dihydrochloride, inhibited both early and late, but probably not intermediate, stages in the intracellular development of S13 phage. This was different from the action of this compound on T1 phage. No relationship was found between structure and action against phage, nor between compounds active against S13 phage and those active against larger phages.
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Studies in the Differentiation between Human and Animal Pollution by means of Faecal Streptococci
More LessSUMMARY: The isolation of faecal streptococci from the excreta of man, cattle and sheep was investigated. The methods compared were (a) heat, (b) tetrathionate, (c) tellurite, (d) thallium salts. The tellurite method proved highly efficient, isolating 97% of strains from human, cow and sheep faeces. A survey of the properties of strains isolated was made. Differential tests based on (a) heat resistance and (b) reducing properties were devised; these divided the streptococci isolated by the tellurite method into groups, some of which were characteristic of the source. The information available seems capable of distinguishing many strains obtained from man from those derived from cows or sheep, and it is suggested it may be of use in tracing sources of pollution in water, milk and other foodstuffs.
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Haemin and Isoniazid Resistance of Mycobacterium tuberculosis
More LessSUMMARY: In confirmation of Fisher’s (1952, 1954a, b) results, haemin was found to act as an apparent growth factor for isoniazid-resistant strains of tubercle bacilli and also powerfully to antagonize the action of isoniazid on drug-sensitive organisms. In extension of Fisher’s work, these effects of haemin were investigated with drug-sensitive and resistant strains of Mycobacterium tuberculosis H37 Rv and B.C.G. The effect of Tween 80 and albumin was also examined. In Fisher’s medium when the nitrogen source was changed isoniazid-resistant strains no longer appeared to be haemin-dependent. Middlebrook’s observations that isoniazid-resistant tubercle bacilli are deficient in catalase (Middlebrook, 1954) and that catalase enables resistant organisms to grow in a deficient medium (Middlebrook, personal communication) were confirmed. Since the dependence of isoniazid-resistant organisms on haemin or catalase seems itself to be dependent on the presence of asparagine in the medium, it is suggested that haemin has a catalase or peroxidase-like role, and that in the presence of asparagine isoniazid-sensitive organisms can remove peroxide, whereas isoniazid-resistant organisms cannot.
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Chemically Induced Aberrations of Mitosis in Bacteria
More LessSUMMARY: Bacillus megaterium was studied cytologically during exposure to a number of toxic agents, including known mitotic inhibitors. Many antibiotics and sodium p-aminosalicylate at inhibitory concentrations induced an increase in the size and optical density of the stained nuclei, and a preponderance of configurations resembling metaphase and anaphase stages. Continued chromosome reduplication results in the establishment of a transient polyploidy. Isoniazid and benzimidazole bring about a decrease in the amount of stainable material in the nucleus. Penicillin and bacitracin produce no obvious changes in the nuclear pattern in this organism. The significance of the aberrations observed is discussed. Further support for the similarity of bacterial nuclei to the nuclei of higher organisms is provided.
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Further Biological Properties of Trichothecin, an Antifungal Substance from Trichothecium roseum Link, and its Derivatives
More LessSUMMARY: Production of trichothecin in submerged aerated cultures of a strain of Trichothecium roseum is described. The antibiotic is active in vitro against certain fungi pathogenic in man, including the causative organisms of some generalized infections and several of the common skin pathogens. In general, the sensitive pathogens were inhibited at trichothecin concentrations of 16 p.p.m. or less and the antifungal activity was not influenced by the presence of blood serum (5%) in the medium. Trichothecin is toxic to laboratory animals; single doses at the rate of 250 mg./kg. intravenously in mice and subcutaneously in rats resulted in death. The antibiotic also produced a reaction when brought into contact with the skin.
The antifungal activity of a series of esters related to trichothecin was of the same order as that of the parent substance. With the exception of esters in which the ethylenic double bond of trichothecolone had been saturated, none of the known derivatives or fission products exhibits more than a very slight activity. The presence of a large excess of -indolylacetic acid did not affect the antifungal activity of trichothecin. This suggests that the effect of the latter in inhibiting plant growth regulating activity of -indolylacetic acid and related substances is not due to molecular combination of the two substances.
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A Fluorescent Derivative of Polymyxin: its Preparation and Use in Studying the Site of Action of the Antibiotic
More LessSUMMARY: A fluorescent derivative of polymyxin (DANSP) was prepared by coupling 1-dimethylaminonaphthalene-5-sulphonyl chloride with the γ amino group of αγ diaminobutyric acid radicals in the polymyxin molecule. As in the case of polymyxin, DANSP is readily absorbed by polymyxin-sensitive organisms and is rapidly bactericidal; cells can be protected against this bactericidal activity by pretreatment with certain cations. Mechanical disintegration of DANSP-treated cells showed that the fluorescent compound was associated with two fractions: (a) cell walls and (b) small particles. Fractionation of three strains of Pseudomonas aeruginosa showed that the fluorescent conjugate was equally distributed between the two fractions, but in the case of three Gram-positive, lysozyme-sensitive, organisms 90 % of the fluorescent conjugate was found in the small particle fraction; controlled lysozyme treatment of these cells showed that the DANSP was associated with a membrane underlying the cell wall from which the small particle fraction is formed on mechanical disintegration.
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The Effect of Partial Steam Sterilization on the Protozoan Fauna of a Greenhouse Soil
More LessComparison of the cultures from treated and untreated greenhouse soil showed that partial steam sterilization decreased the number of protozoan species, delayed the development of the fauna, but favoured the growth of the surviving ciliate species. This was particularly true of the treated topsoil.
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Particle Counts of Haemagglutinating Viruses
More LessThe electron microscope was used to make particle counts of the viruses of Newcastle disease of fowls, fowl plague, mumps and influenza C. Two counting techniques previously described were also used, and correlations with simultaneous measurements of haemagglutination and infectivity were made.
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The Formation of Extracellular Nitrogen Compounds by Fungi
More LessThe production of nitrogen compounds in the culture medium by Scopulariopsis brevicaulis and other fungi has been studied. The formation of extracellular nitrogen compounds accompanied the primary assimilation of ammonia, nitrate and organic nitrogen in all experimental conditions so far investigated among the various factors studied. The amount of these extracellular nitrogen compounds was affected markedly only by the supply of certain trace elements. It was lowest when the concentration of trace elements was high, and increased as the concentration of trace elements approached that limiting growth. Most of the extracellular nitrogen appeared to be peptide in nature, yielding some 14 amino acids on hydrolysis. The fungus was unable to assimilate the extracellular nitrogen compounds formed but assimilated the constituent amino acids when these were liberated by acid hydrolysis.
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Observations on the Morphology of Streptomyces griseus in Submerged Gulture
More LessThe effects are described of three different media, based on urea, glycine or meat casein digest as nitrogen sources, on the morphology of Streptomyces griseus when grown in submerged culture. The urea medium was characterized by an alternation of morphological generations similar to that described by Klieneberger-Nobel for surface cultures: ‘primary mycelium’ alternated with ‘secondary mycelium’, the two generations being separated by an ‘initial cell’ stage. ‘Secondary mycelium’ sporulated to give ‘secondary mycelium spores’. The other two media did not support ‘initial cell’ formation, but led either to the development of intercalary ‘chlamydospores’ or lysis without sporulation. The media based on urea or glycine were used in convenient and satisfactory techniques for the production of ampoules containing large numbers of lyophilized spores which stored satisfactorily.
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The Inheritance of Differences in Growth Rate in Escherichia coli
More LessSUMMARY: In cultures from single cells of Escherichia coli grown under anaerobic conditions there are variations in rate of growth of the individual colonies as measured by their diameter after a short incubation. When small and large colonies are selected the populations derived from them inherit the tendency to produce correspondingly smaller or larger colonies than the mean of those produced by the parent strain. When the growth conditions are altered then the selected character will be lost.
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The Differences in Antibiotic Sensitivity of Closely Related Single Cells of Proteus vulgaris
More LessSUMMARY:Evidence is offered that when a single bacterial cell divides the daughter cells are frequently unlike one another. This can be demonstrated by separating cells, allowing them to divide and then transferring individuals derived from them to agar containing a suitable concentration of antibiotic. Differences between single cells can be tested by four criteria: (1) division; (2) growth without division: (3) ability to resume division when transferred back to normal broth; (4) failure to lyse.
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The Role of Divalent Cations in the Multiplication of Staphylococcal Bacteriophages
More LessSUMMARY:The staphylococcal typing phages require divalent cations for a stage in phage growth which is probably that of penetration. When phage is adsorbed to the cell surface of sensitive cocci and a chelating agent is added, there is a short period during which the phage particle may be inactivated and its lethal effect on the coccus prevented. Cocci attacked by phages of serological group A show penetration of the phages in distilled water + CaCl2, or + MgCl2, or to a less extent + SrCl2. The phages of group B are unable to penetrate in presence of SrCl2 and in some cases MgCl2 is only partially active as compared with CaCl2. Ca ions appear to be required specifically at a late stage in phage synthesis since the average yield of phage/coccus increases with increasing concentration of CaCl2; the addition of a chelating agent towards the end of the latent period depresses the yield of phage.
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The Induced (Adaptive) Biosynthesis of β-Galactosidase in Staphylococcus aureus
More LessSUMMARY: Staphylococcus aureus strain Duncan readily synthesized the adaptive (inducible) enzyme β-galactosidase in washed suspension when supplied with a mixture of amino acids and an inducer. The amount of enzyme produced was a function of the quantity of amino acids supplied and the rate of synthesis was determined by the concentration of inducer in the system. Galactose was a highly active inducer, lactose a relatively feeble one. Production of the enzyme ensued after a lag period which could be shortened by the addition of glucose or sodium lactate and further shortened by supplying a mixture of purines and pyrimidines to the system. Enzyme formation was strongly inhibited by various antibacterial agents.
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Factors Involved in the Production of a Novel Kind of Derangement of Storage Mechanism in Living Holotrich Giliate Protozoa from Sheep Rumen
More LessSummary: When metabolizing glucose or other fermentable sugar in vitro at a temperature 8–12° below the normal rumen temperature, three species of rumen holotrich ciliates were liable to exhibit highly abnormal appearances which were not seen at 35–38°. These abnormal appearances consisted essentially in a contraction and fusing together of the bulk of the storage polysaccharide (amylopectin) granules into a narrow central zone in the endoplasm. The outer clearer endoplasmic region, however, still contained numerous discrete granules in Isotricha prostoma and I. intestinalis but not in Dasytricha ruminantium. The abnormality was not quickly lethal to the organisms and appeared not to involve any alteration in shape or position of the macro-nucleus. The presence of rumen liquor, with all its soluble constituents but not necessarily its bacteria, is required for a high incidence of abnormality and the organisms should also initially contain but little storage polysaccharide. Evidence is presented in favour of the view that the abnormalities are connected with the utilization (auto-fermentation) of storage polysaccharide rather than with its synthesis. Nevertheless, the abnormalities cannot be induced in Isotricha when starch grains (vegetable or protozoan) have first been ingested.
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The Intestinal Microflora of the Clothes Moth Larva Tineola bisselliella in relation to Wool Digestion
More LessSummary: The intestines of clothes moth larvae, Tineola bisselliella, examined usually contained very few micro-organisms; this may be related to the high pH values of the intestinal contents. It was concluded that bacteria play no part in the digestion of wool by these larvae.
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