- Volume 66, Issue 2, 1971
Volume 66, Issue 2, 1971
- Biochemistry
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Amino Sugars in the Cell Walls of Pseudomonas Species
More LessSUMMARY: Fucosamine has been identified as a component of the walls of Pseudomonas denitrificans and P. fragi, and quinovosamine as a component of the walls of P. fluorescens, P. mucidolens, P. putida, P. stutzeri, P. syncyanea and P. synxantha. A third amino sugar, present in the walls of P. synxantha and possibly in those of P. fluorescens, was apparently 3-amino-3,6-dideoxyglucose.
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- Development And Structure
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The Zoospore of Allomyces
More LessSUMMARY: The arrangement of cellular organelles within the zoospores of Allomyces macrogynus and A. neo-moniliformis was found to be very similar to that observed in the zoospores of Monoblepharella (Monoblepharidales). Principal among these differences are the presence in Allomyces of a distinct nuclear cap, a set of 27 microtubules, a nucleus adjacent to the kinetosome, and the side body which includes the here-named Stüben bodies. Certain previous observations, including the reported absence of microtubules, of the ultrastructure of the zoospore of Allomyces have been corrected or amended.
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The Effect of Nickel on a Marine Bacterium: Fine Structure of Arthrobacter marinus
More LessSUMMARY: Rod-shaped Arthrobacter marinus, normally 2 × 4 μm., enlarged to 10 to 15 μm. diam. after 6 h. growth with 4 × 10−4 M-NiCl2. Electron microscopy of ultra-thin sections showed a greatly plasmolysed megalomorph with the space originating at the poles after 1 to 2 h. Nuclear material retained its filamentous structure and the number of its loci increased; ribosomal material did not change in density, size or arrangement. The inner dense layer of the wall disappeared, leaving a dense-light-dense profile; the cytoplasmic membrane remained unchanged. Accumulated mesosomes may have accounted for the high degree of reticulation in the cytoplasm. Blebs of 0.05 to 0.1 μm. diam. on the exterior of the wall, delineated by a double membrane, appear to originate from the outer membrane.
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- Genetics And Molecular Biology
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Mapping the δ-Aminolaevulinic Acid Synthetase Locus in Bacillus subtilis
I. Kiss, I. Berek and G. IvánovicsSUMMARY: HemA mutants of Bacillus subtilis 168 requiring δ-aminolaevulinic acid for their growth were isolated either following selection with streptomycin or by exposure to copper sulphate, and studied in reciprocal transduction experiments. Both groups of mutants were found to be genetically identical and the hemA locus was unlinked to a streptomycin resistance marker; it was linked to the group III markers mapped by Dubnau, Goldthwaite, Smith & Marmur (1967) and is located between the ilvA1 and phe-1 loci.
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Diaminopimelic Acid and Lysine Auxotrophs of Pseudomonas aeruginosa 8602
More LessSUMMARY: Lysine auxotrophs have been isolated from Pseudomonas aeruginosa 8602. Three of the mutants were deficient in diaminopimelate decarboxylase and accumulated meso- and ll-diaminopimelic acid (DAP) but otherwise were indistinguishable from the parent strain. The fourth mutant required lysine for optimal growth, grew slowly on meso- but not ll-DAP, and the DAP which accumulated in large amounts was solely the ll-isomer. This mutant was deficient in diaminopimelate epimerase. No significant differences were detected between its wall composition and that of the parent strain but it was particularly sensitive to carbenicillin.
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Increased Resistance to Several Antibiotics by One Mutation in an R-factor, R 1a
More LessSUMMARY: An Hfr strain G11 and an F− strain D1 of Escherichia coli K 12 both containing the R-factor R 1a were treated with ethyl methane sulphonate (EMS). Mutation of the bacteria to high ampicillin resistance occurred at a frequency of 10−3 to 10−4 and it was coupled with a simultaneous increase in resistance to chloramphenicol, streptomycin and sulphanilamide. Resistance to all the antibiotics was infective. Increased ampicillin resistance was due to increased penicillinase activity of the bacteria. In a strain containing a mutant R-factor (R1 B1) this was due to an increased quantity of an enzyme that seemed to be identical to that of a strain containing the unmutated R 1a. Metabolism of chloramphenicol in strains containing R1 B1 was greater than in those with R 1a. Mating experiments with an Hfr strain carrying R 1a or R1 B1 revealed that the two R-factors reduced fertility to about the same extent. Pair formation was two to three times greater in the presence of R1 B1 than in the presence of R 1a, and R-factor transfer was increased more than chromosome transfer. It is likely that the R 1a genome is read two to three times more efficiently in strains containing the mutated R1 B1, perhaps due to an increased number of copies of the R-factor genome per bacterium.
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Genetic Transformation in Proteus mirabilis
More LessSUMMARY: A method is described for the isolation of biologically active DNA from Proteus mirabilis strain 13 which could transform auxotrophic mutants of P. mirabilis to prototrophy. This DNA preparation did not transform similar mutants of P. vulgaris. Optimal conditions for transformation were pH 8·5 to 9·5 for the lysate during DNA extraction, DNA concentration of 16 μg./ml. and growth of recipient cells for 5 h. before exposure to DNA.
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- Medical Microbiology
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Red Cell-sensitizing Antigens of Lactobacilli
More LessSUMMARY: Three serologically distinct red cell-sensitizing antigens were identified in lactobacilli. Two possessed the serological specificity of the streptococcal Hickey (polyglycerophosphate) and 44 sensitizing antigens. All resembled the streptococcal antigens in physical properties and in being excreted, sometimes in considerable amount. They were extracted from intact bacteria by a variety of procedures and were thought to have an intramural location. The Hickey antigen was present in sufficient concentration on the cell wall surface of certain strains to take part in bacterial agglutination reactions. The relationship of sensitizing antigen distribution to various taxonomic parameters of the lactobacilli is considered.
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- Physiology And Growth
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Studies on the Physiology of Heterocyst Production in the Nitrogen-fixing Blue-green Alga Anabaena sp. l-31 in Continuous Culture
More LessSUMMARY: Induction of heterocysts in the blue-green alga Anabaena sp. l-31 is totally inhibited by potassium nitrate in batch cultures whereas in continuous cultures no inhibition is observed at high dilution rates. When nitrate is utilized ammonia accumulates in the growth medium, the quantity of extracellular ammonia declining with increasing dilution rate.
The rate of release of ammonia per cell increases with decreasing density of organisms, and induction of heterocysts is consistently observed when ammonia release per cell exceeds 2 × 10−10 μg. It is inferred that such excessive release depletes the level of intracellular ammonia causing the induction of heterocysts.
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Thermal Lysis of Bacterial Membranes and Its Prevention by Polyamines
P. H. Ray and T. D. BrockSUMMARY: Protoplasts of Sarcina lutea and Streptococcus faecalis underwent thermal lysis when heated to 60° and above. [14C]Glycine was released from the internal pool of Strep, faecalis at 50°. Spermine, spermidine, cadaverine and Mg2+ partially protected protoplasts against thermal lysis.
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Growth Measurements on Surface Colonies of Bacteria
More LessSUMMARY: Growth of colonies of Pseudomonas fluorescens on trypticase soy agar (TSA) and glucose-salts agar (GSA) is described in terms of diameter, height and viable count and of calculated volume and viable cell density. All increased with time except viable cell density, which was constant for colonies at 3.11 × 108 cell/mm3 on TSA and 10.08 × 108 cells/mm.3 on GSA. Colony diameter increased linearly at 0.0585 mm./h. on TSA and 0.0594 mm./h. on GSA, but the modes of growth were very different. Colonies on TSA increased in both diameter and height while those on GSA increased mainly in diameter, so colony volumes on the two agars differed. Colony diameters of Micrococcus caseolyticus and eight Gram-negative rods also increased linearly with time. We propose that a linear increase of colony diameter with time represents the steady state growth of bacterial colonies.
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Alteration of Fungal Morphology Induced by a Substance from Bacillus cereus
More LessSUMMARY: A strain of Bacillus cereus inhibited growth of some fungi and induced the formation of spherical cells. The substance responsible was identified as a thermostable protein active between pH values of 4.0 to 7.0. The substance affected fungi from various classes, but was not equally effective with different fungi. Leakage from cells exposed to the substance was demonstrated. The relation of this substance to the lysins of B. cereus is discussed.
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Effect of Dissolved Oxygen on Growth Yield and Aldolase Activity in Chemostat Culture of Azotobacter vinelandii
More LessSUMMARY: Glucose-limited and oxygen-limited chemostat cultures of Azotobacter vinelandii were agitated at 240, 340, 560 and 780 rev./min. In the oxygen-limited culture the growth yield ranged from 0.2 to 0.25 mg. bacteria/mg. glucose, considerably higher than 0.03 to 0.18 observed when glucose was limiting. This finding suggests that the dissolved oxygen interferes in the metabolism of growing Azotobacter. Aldolase activity, but not that of glyceraldehyde-3-phosphate dehydrogenase, isocitrate dehydrogenase or isocitrate lyase, was proportional to dissolved oxygen concentration in each culture. The carbon balance indicated no products other than the bacteria and carbon dioxide.
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- Short Communications
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Fatty Acid Nature and Adjuvant Activity of Wax D from Mycobacterium tuberculosis
I. J. Hiu and J. L. AmielSUMMARY: Wax D, a chloroform-soluble and boiling-acetone-insoluble fraction extracted from various human strains of mycobacteria, showed characteristic biological activities such as Freund-type adjuvant activity (Raffel, 1950; White, Jollès, Samour & Lederer, 1964) and the induction of adjuvant arthritis in rats (Pearson, 1959; Pearson, Wood, McDaniel & Daft, 1963). Wax D from human strains was found to be peptidoglycolipid consisting of unsaturated fatty acid (mycolic acid) esters of mucopolysaccharide containing a peptide moiety of alanine, glutamic acid and meso-α-α'-diaminopimelic acid (Asselineau, 1951; Asselineau, Buc, Jollés & Lederer, 1958). Previous work from this laboratory has shown the importance of fatty acid content for the adjuvant activity of the wax D of a human strain, Peurois (Hiu, Amiel & Jollès, 1969). This communication reports an increase in adjuvant activity after hydrogenation of the fatty acids forming the lipid portion of the wax D from the human strains Peurois and Canetti.
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Chloride Uptake by Mycelium of Neocosmospora vasinfecta and Its Inhibition by Glucose
A. G. Miller and K. BuddSUMMARY: Studies of the transport of inorganic ions by fungi have lagged behind those of most other groups of organisms. In the yeast Saccharomyces cerevisiae, which is the exception to this statement, most attention has been focused on cation transport: absorption of PO4 3− and SO4 2− has been examined, but the organism ‘behaves as though impermeable to Cl−’ (Rothstein, 1965; of. Conway & Downey, 1950). However, during K+ uptake by the mycelial ascomycete Neocosmospora vasinfecta net Cl− absorption also takes place, though not at the same rate (Budd, 1969a). This report confirms the absorption of Cl− in this organism and describes the effect of extracellular glucose on this process.
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Electrophoretic Protein Spectra of Wild-type and Isogenic Monokaryons of Coprinus lagopus
More LessIn their early investigation o the means by which the incompatibility factors of the incompatibility actors of the tetrapolar basidiomycete Schizophyllum commune find physiological or biochemical expression, Raper & Esser (1961) stresse the need to use isogenic strains to minimize differences in proteins other than those attributable to the incompatibility system. Recently Wang & Raper (1969) have shown disc electrophoresis in polyacrylamide gel to be valuable in investigating the protein spectra of various mycelial types of this fungus and have used their results to test the validity of a model for the model of action of the incompatibility factors. In a preliminary investigation of the applicability of disc electrophoresis to the examination of the proteins of the related fungus Coprinus lagopus sensu Buller, the method described was found to give good results. The advantage of using ‘isogenic’ strains of Coprinus is open to question.
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