摘要:

An attempt to isolate a self-inhibitor of spore germination inGeotrichum candidumLink was unsuccessful because of the instability of the self-inhibitor. The ability of different carbon sources to stimulate germination and support somatic growth was tested in self-inhibitory conditions. Acetate, fructose, galactose, and glycerol supported both germination and somatic growth. All the fatty acids tested allowed germination but were unable to support vegetative growth; conversely mannitol could not induce germination but did support vegetative growth. Measurements of oxygen uptake by germinating arthrospores at various arthrospore concentrations showed a decrease in oxygen uptake per spore as the spore concentration (= self-inhibitor concentration) increased. Oxygen uptake per spore by dormant arthrospores also decreased with increasing spore concentration. Spore age was another factor influencing oxygen uptake by dormant spores; oxygen uptake per spore decreased with increasing spore age up to 7 days. Continued aging did not decrease the rate of oxygen uptake any further.

ISSN:0008-4166    

DOI:10.1139/m73-151

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Phycomyces blakesleeanuswas grown in a minimal glucose–asparagine broth medium supplemented with either 2-methyl-4-amino-5-hydroxymethylpyrimidine-4,7-14C or 4-methyl-5-(2-hydroxyethyl)-thiazole-2-14C and the corresponding non-labeled moiety of thiamine. Extracts of mycelia and of culture filtrates were tested for the presence of intermediates formed in the biosynthesis of thiamine byP.blakesleeanus. By combinations of ion-exchange and thin-layer chromatography, autoradiography, and bioautography, the following compounds were identified: 4-methyl-5-(2-phosphorylethyl)thiazole, 2-methyl-4-amino-5-phosphorylmethylpyrimidine, 2-methyl-4-amino-5-pyrophosphorylmethylpyrimidine, and thiamine monophosphate.

ISSN:0008-4166    

DOI:10.1139/m73-152

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Immunophylogenic relationships of nocardiae to other microorganisms were investigated by means of the immunodiffusion procedures, using 493 cytoplasm preparations and 218 anticytoplasm sera. The cytoplasm antigens of nocardiae were found mainly to be immunologically related to the saprophytic and scotochromogenic mycobacteria, as well as to the streptomycetes possessing the cytoplasmic determinanta. Only a few species of nocardiae cross-reacted with the anticytoplasm sera againstActinomyces israelii,Micromonospora, andMicropolyspora; but none was found to be related directly to the cytoplasm antigens of Eubacteriales. It is suggested that the nocardiae evolved at a later stage than the streptomycetes and candidas through which they are indirectly related to the Eubacteriales.

ISSN:0008-4166    

DOI:10.1139/m73-153

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

A simple gas-chromatographic method was devised for the detection of mycolic acids present in strains of Actinomycetales with a type IV cell wall (meso-DAP, arabinose, and galactose). Results obtained in the study of 89 such strains has permitted the authors to assign them to either the genusMycobacterium(strains containing true mycolic acids) or to the genusNocardia(strains containing nocardomycolic acids).Strains of "Nocardia farcinica" were found to belong to the genusMycobacteriumand thus the name of this species should be considered anomen dubium. Strains of "Mycobacterium rhodochrous," "M.brevicale," and "M.thamnopheos" did not contain true mycolic acids and their assignment to the generaNocardiaorCorynebacteriumwas considered.

ISSN:0008-4166    

DOI:10.1139/m73-154

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

We have studied aspects of interbacterial ecology with nutritionally dependentStaphylococcus aureusstrains; they were grown in association withPseudomonas aeruginosain systems of mixed cultures and infections in vitro in a semisynthetic medium and in vivo in mouse peritoneal cavity and rabbit skin. In mixed cultures and inP.aeruginosaculture filtrates, thymine and tryptophan deficiencies in staphylococci were partly overcome. This is probably becauseP.aeruginosasupplied the essential metabolites required to ensure growth; however, other metabolic activities could also be involved. Other experiments showed that the sensitivity of thymineless staphylococci to nucleoside inhibitions was alleviated. In mixed infections withP.aeruginosa, theS.aureusthymineless strain has shown a greater ability to survive in the peritoneal cavity of mice than when injected alone, even when one species was injected after the other with different doses of bacteria. The examination of the liquid from the peritoneal cavity of infected mice by fluorescence microscopy after fluorochroming with acridine orange or auramine O has revealed thatPseudomonasendotoxin seems to damage leucocytes and consequently reduces the phagocytosis ofStaphylococcuscells.Necrosis in rabbit skin was mainly due toS.aureuswhen both species were injected together intradermally; the thymineless strain was less harmful than the parent strain.It seems that survival and even growth of nutritionally dependent strains of a bacterial species can be favored by the metabolic activities of another species in mixed cultures and infections, in this instanceS.aureusbyP.aeruginosa. This phenomenon among others could be a determinant of bacterial pathogenicity for nutritionally dependent pathogenic bacteria; thus associated organisms could determine the effective pathogenicity of nutritionally dependent bacteria by contributing essential nutrilites at the site where infection is initiated.

ISSN:0008-4166    

DOI:10.1139/m73-155

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The most probable numbers (MPN) of spirilla were estimated in samples ofCladophora, pond water and mud, stream water and slime, trickling filter effluent, standing hay, field drainage, cow manure, woods soil, and cultivated field soil. Six formulations of MPN media were compared: vermiculite–albumin, nutrient gelatin agar, calcium lactate, artificial activated sludge, 5-fluorouracil, and hay infusion. Vermiculite–albumin generally gave the greatest numbers of three morphological types of spirilla. Spirilla were about 4% of the total bacterial population associated withCladophora; about 0.1 to 0.6% of the bacteria of mud, water, slime, trickling filter effluent, and cow manure; and less than 0.01% of the remainder except hay, in which they were not found.

ISSN:0008-4166    

DOI:10.1139/m73-156

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Intracellular polyglucose granules have been isolated from late log-phase cells ofClostridium pasteurianum. These granules are spherical in shape, heterogeneous in size, and surrounded by a membrane coat which lacks the characteristics of a typical unit membrane. Freeze-etching reveals projections of 12 to 16 nm in diameter in the matrix of the granules, which suggest the presence of polysaccharide fibrils.

ISSN:0008-4166    

DOI:10.1139/m73-157

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

A marine bacterium produces appendages (spines) which consist of rigid tubes, about 70 nm in diameter. These are expanded at the base and attached to, but not originating in, the cell wall. The wall of the spine is smooth on the inside but ridged on the outside. The ridges, which appear as striations in shadowed or negative-stained preparations, are continuous along the length of the spine and helically arranged. The fine structure of these spines is demonstrated.

ISSN:0008-4166    

DOI:10.1139/m73-158

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

After exogenous carbon-independent macroconidium germination byFusarium solaniat 1 × 104conidia/ml in axenic culture, chlamydospores were formed terminally on germ tubes. Low chlamydospore germination was supported under axenic conditions by 0.004 ng C/spore (calculated value), supplied as ethanol, or by 0.04 ng C/spore, supplied as glucose or several other sugars. Chlamydospores in direct contact with a nonsterile loamy fine sand soil (6.2 μg NH4+-N and 7.1 μg NO3−-N/g soil) had a greater exogenous carbon requirement and did not germinate until 2.0 ng glucose-C/spore was supplied. Supplemental exogenous nitrogen, added as NH4Cl, had little or no influence on percentage of germination at the levels of exogenous carbon supporting low germination, both in soil and in axenic culture. However, increasing the amounts of glucose plus NH4Cl supplied per spore increased percentage of chlamydospore germination more than increasing the amount of glucose alone for both soil and axenic systems. In axenic culture, complete germination was observed at 2.0 ng C plus 0.13 ng N/spore. Greater than 90% germination occurred for chlamydospores in contact with soil at the highest glucose plus NH4Cl level examined (200 ng C plus 13 ng N/spore), but not in glucose alone. Sterile acid-washed sand did not have a similar adverse effect on chlamydospore germination. Chlamydospores were nearly 100% germinable after 1 year of incubation in an inorganic salts medium under axenic conditions.

ISSN:0008-4166    

DOI:10.1139/m73-159

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The extent of association between deoxyribonucleic acid (DNA) from various actinomycetes with reference DNA samples from two strains ofNocardia erythropolishas been used as an index of relatedness.N.erythropolis,N.canicruria, and particular cultures designated asN.corallinaandN.opacaconstitute a genospecies, on the bases of ability to form DNA hybrid molecules and ability to participate in genetic recombination. The lack of reciprocity in the DNA reassociation assays involving selected strains ofN.erythropolisindicates that the DNA from particular lineages possesses unique nucleotide sequences. The taxonMycobacterium rhodochrousis heterogeneous and contains at least two discrete populations. The present results do not clarify the relationships of theN.erythropolisgenospecies to the other nocardiae, streptomycetes, or mycobacteria. The differences in extent of hybrid DNA duplex formation at exacting and non-exacting incubation temperatures reflect the degree of matching between the compared nucleotide sequences. On this basis, actinomycete DNA samples differ from one another by nucleotide alterations dispersed throughout the genome. DNA hybridization is a sensitive assay for molecular evolution and may be able to detect neutral and nearly neutral mutations that are not recognized phenotypically.

ISSN:0008-4166    

DOI:10.1139/m73-160

出版商:NRC Research Press    

年代:1973

数据来源: NRC