摘要:

Cell wall lipopolysaccharides (LPS) prepared from oxidase-positiveMoraxella duplexand from oxidase-negativeMicrococcus calco-aceticus(a presumptive moraxella) containedD-glucose,D-galactose, glucosamine, galactosamine, lipid A, ethanolamine, fatty acids, phosphate, and protein. The lipid A moieties prepared from the LPS fractions were composed primarily of hexosamines, ethanolamine, fatty acids, and phosphate with minor amounts of the other LPS constituents. The LPS fromM.duplexandM.calco-aceticushad the same neutral sugar composition but differed markedly in their hexosamine composition. Galactosamine was the major hexosamine component ofM.duplex; also present was an unidentified amino sugar and a small amount of mannosamine. In contrast, glucosamine was the major hexosamine component ofM.calco-aceticuswith a lesser amount of galactosamine and no mannosamine. The presence of galactosamine as the major component of the lipid A ofM.duplexsuggests that this fraction has a novel structure which differs from the poly-D-glucosamine 'backbone' structure assigned to lipid A. The fatty acid compositions of the lipid A from the two species were mutually similar and consisted mainly of hydroxylauric, hydroxymyristic, and C17-cyclopropane fatty acids. The LPS fractions of the two organisms studied resemble that ofNeisseria catarrhalisand differ from those of the true neisserias.

ISSN:0008-4166    

DOI:10.1139/m70-001

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

WhenAzotobacter chroococcumandPseudomonassp. were grown together on nitrogen-deficient azotobacter agar medium, the growth of the azotobacter was inhibited. Studies were undertaken to explain this microbial interaction. No demonstrable active diffusible factor was found in cell-free filtrates (neutralized) and extracts. Experiments with indicator agar plates and HEPES-buffered liquid medium suggested that the interaction was attributable to the transformation by the pseudomonad of metabolic intermediates of azotobacter to inhibitory acidic end products. The high sensitivity ofA.chroococcumto acidity resulted in the inhibition phenomenon. This microbial association is discussed briefly from the point of view of the ecology of the two species.

ISSN:0008-4166    

DOI:10.1139/m70-002

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The production of extracellular endopeptidase byAeromonas proteolyticaMerkelet al. was found to be influenced by a number of nutritional factors. An inverse relationship existed between endopeptidase synthesis and growth in media containing increasing quantities of asparagine. This effect was accentuated by the individual addition of glycerol, glucose, sucrose, or acetate as supplemental carbon sources. The addition of small quantities of complex mixtures of peptides to growth media containing either acid-hydrolyzed casein or asparagine as the organic component greatly stimulated endopeptidase synthesis. The data suggest that endopeptidase synthesis is repressed whenA.proteolyticais grown in the presence of certain individual amino acids, that glycerol and some other easily metabolized compounds cause catabolite repression of endopeptidase synthesis, and that endopeptidase production is stimulated by peptides of unknown identity.

ISSN:0008-4166    

DOI:10.1139/m70-003

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

In media containing simple nitrogen sources, the highest yields of aminopeptidase were obtained fromAeromonas proteolyticaMerkelet al. when the organism was grown in asparagine or sodium nitrate supplemented with glycerol; growth in a medium containing enzymatically hydrolyzed casein, however, produced 10 times more enzyme than that observed with the best simple nitrogen sources. The presence of glycerol (0.4%) in a 0.2% asparagine medium resulted in 2.5 times more enzyme although growth was not similarly stimulated. When acid-hydrolyzed casein was the nitrogen source, aminopeptidase synthesis was about three times greater than that obtained with asparagine and glycerol but only one-third of that observed when enzymatically hydrolyzed casein was used. The production of aminopeptidase was greatly enhanced by the addition of small quantities of peptide mixtures to media containing either acid-hydrolyzed casein or asparagine as the primary nutrient source. The data suggest that the synthesis of aminopeptidase is under multiple controls which involve the action of short chain compounds and peptides.

ISSN:0008-4166    

DOI:10.1139/m70-004

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

An isolate ofFusarium oxysporumgrown in a solution of monobasic potassium phosphate and magnesium sulfate rarely produced chlamydospores. However, when the salt solution was amended with 0.125 mg to 2.0 mg per liter of either glucose or magnesium carbonate, there was an abundant production of chlamydospores within 3 to 4 days after inoculation. While an organic or inorganic source of carbon stimulated chlamydospore formation, repression of chlamydospore production occurred with glucose and magnesium carbonate levels above 2.0 mg per liter. The addition of either an ammonium or nitrate source of nitrogen to the salt solution did not produce additional chlamydospores.

ISSN:0008-4166    

DOI:10.1139/m70-005

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The effect of the presence of catabolites in the growth medium on the synthesis of the two glutamate dehydrogenases ofNeurospora crassais reported. It has been demonstrated that the nicotinamide adenine dinucleotide (NAD) specific glutamate dehydrogenase is subject to repression by sucrose and glucose. Nicotinamide adenine dinucleotide phosphate (NADP) specific glutamate dehydrogenase, on the other hand, is induced by increasing concentrations of the catabolite. These data suggest that a reciprocal relationship exists between these two enzymes during synthesis in the presence of catabolites. Growth in higher concentrations of sucrose led to the formation of two isoenzymes of the NADP-specific enzyme; the second or the minor isozyme is not produced at very low catabolite concentrations. The catabolite effects produced by sucrose are overcome by glutamate, if the latter is incorporated into the growth medium. Glutamate represses both the isozymes of NADP-specific enzyme.

ISSN:0008-4166    

DOI:10.1139/m70-006

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The oxidation of both saturated and unsaturated fatty acids by a water isolate and a pathogenic leptospire is reported. Evidence is presented for the existence of an adenosine triphosphate dependent fatty acid activating enzyme in the water isolate, and measurement of the reactions of β-oxidation in cell-free extracts of both strains is described. It was concluded that fatty acid degradation by β-oxidation constitutes a major catabolic pathway inLeptospira.

ISSN:0008-4166    

DOI:10.1139/m70-007

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Rabbit erythrocytes treated with the alpha toxin ofStaphylococcus aureus, strain "Wood-46", liberate substances which contain nitrogen, absorb at 280 mμ, and react with Folin phenol reagent. The susceptibility of different erythrocyte species to alpha toxin is correlated with (a) the quantity of reaction products released by toxin from the cells and (b) the degree of natural proteolytic activity possessed by the cells. Alpha toxin was, however, without effect upon albumin, fibrinogen, casein, and hemoglobin even when these proteins had been denatured with urea. In view of the evidence, it is suggested that the toxin is secreted by theStaphylococcusas an inactive protease which must be activated by another protease. The degree of activity of this protease in various red cell species would explain their differential sensitivity to alpha toxin.

ISSN:0008-4166    

DOI:10.1139/m70-008

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The initiation of germination ofBacillus subtilisspores in complete medium and in phosphate buffer plus the enzyme subtilopeptidase is inhibited by chlorocresol, but the activity of the enzyme alone is not. This suggests that proteolytic activity is not the primary site of inhibition. Germination of spores of this organism can be initiated with one of each of five amino acids, viz.L-alanine,L-cysteine,L-valine,L-leucine, andL-isoleucine. The germination initiated by these amino acids is reversibly inhibited by chlorocresol. These results strongly suggest that the inhibitor prevents the initiation of germination of bacterial spores at the level of amino acid use, both in complete medium and with subtilopeptidase.

ISSN:0008-4166    

DOI:10.1139/m70-009

出版商:NRC Research Press    

年代:1970

数据来源: NRC