摘要:

Sixteen strains of 11 facultatively anaerobic species of the genusBacilluswere tested for their ability to sporulate anaerobically on common laboratory media. Reliable data depended on a method providing anaerobic conditions quickly.Bacillus macerans(one strain tested) andB.polymyxa(two out of two strains tested) sporulated anaerobically without added nitrate. ButB.licheniformis(one out of two strains tested) required nitrate for "anaerobic" sporulation. Anaerobic sporulation ofB.maceransandB.polymyxaon potato extract agar was inhibited by nitrate.

ISSN:0008-4166    

DOI:10.1139/m74-201

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

A strain ofArthrobactercatabolizes cyclohexanecarboxylic acid by a pathway involving aromatization of the ring before its cleavage. The pathway includes the following intermediates:trans-4-hydroxycyclohexanecarboxylic acid, 4-ketocyclohexanecarboxylic acid,p-hydroxybenzoic acid, protocatechuic acid, and β-ketoadipic acid. The oxidation of 4-hydroxycyclohexanecarboxylic acid by cell extracts specifically requires NAD+and results in the production of 4-ketocyclohexanecarboxylic acid. The latter compound is oxidized in the presence of a suitable electron acceptor, such as oxygen, methylene blue, or 2,6-dichlorophenolindophenol, top-hydroxybenzoic acid.

ISSN:0008-4166    

DOI:10.1139/m74-202

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Electron-microscopic examination of gingival plaque microflora showed a bacillus-like, microencapsulated, thick-walled organism with a previously unreported structure. This structure, which is not an example of fimbriae, flagellae, or attached extracellular polysaccharide, is a tuft of thin fibers about 0.3 μm long at only one end of the cell. The fibers begin in or near to the cell wall and pass through the microcapsule to the outside. The name lotussy is proposed for this new structure and the name lotuslifa for an individual fiber or filament.

ISSN:0008-4166    

DOI:10.1139/m74-203

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Many planktonic blue-green algae produce natural chelators which enable them to grow at high pH's in the absence of artificial chelators. The growth of 10 cyanophytes without an added chelator was found to differ widely with the algal species. Bacteria-containing cultures ofAnabaena cylindrica,Anacystis nidulans,Lyngbyasp.,Microcystis aeruginosa,Nostoc muscorum, andPhormidium foveolarumproduced their own chelators and grew just as well as the controls with artificial chelating agents. Bacteria-containing cultures ofAnabaena circinalis,Gloeotrichia echinulata,Oscillatoria rubescens, andAphanizomenon flos-aquaedid not produce chelators and, in the absence of artificial agents, grew poorly or perished early. The alga-produced, extracellular chelators were water-soluble and capable of chelating and controlling metal compounds that would exist in colloidal form at pH's above 7. Accordingly, in the absence of artificial chelators, the non-chelator-forming species grew in the filtrates of the chelator-forming algae the same as in the presence of artificial agents. Bacteria were not involved in the formation of natural chelators, since axenic cultures ofAnabaena circinalis,Anacystis nidulans,Microcystis aeruginosa,Nostoc muscorum, andPhormidium foveolarumin the absence of artificial chelators performed about the same as the bacteria-associated species. Also, the filtrates of axenic, chelator-formingAnacystiscultures had the same growth-stimulating effect on non-chelator-forming species as filtrates from bacteria-associated cultures. The natural chelators showed partial thermolability.While the growth of chelator-forming species in the absence of artificial chelators was normal during the logarithmic phase, a peculiar, continuing production of total organic matter was observed with strongly declining cell numbers ofLyngbya,Microcystis, andPhormidium. The terminal cultures of these species were gelatinous, owing to the presence of extracellular matter, probably consisting of polysaccharides.

ISSN:0008-4166    

DOI:10.1139/m74-204

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Conidial formation inC.purpureais correlated with a rising ATP utilization, an almost constant rate of protein synthesis, a constant level of intracellular orthophosphate, an accumulation of mycelial lipids, and an increase in the activities of citrate synthase, isocitrate lyase, malate synthase, and intra- and extra-cellular proteinases. In the culture, stringent control of tryptophan biosynthesis is absent. Conidial formation is stimulated by MnCl2(5.10−4 M) and suppressed by ergotamine (5.10−4 M), ergometrine (5.10−4 M), and glycerol (5.10−3 M), respectively. Ergotamine also lowers the activity of leucineaminopeptidase from the fungus. Alkaloids are synthesized only after conidial formation and the growing stage. In cultures treated with conidiation inhibitors (ergotamine and (or) glycerol), the alkaloid yield is enhanced. It is hypothesized that the concentration of intracellular tryptophan which accumulates during aging is lowered by conversion to alkaloids which are themselves capable of positive feedback which enhances further loss of tryptophan.

ISSN:0008-4166    

DOI:10.1139/m74-205

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Ten strictly anaerobic bacterial strains belonging to the generaInflabilis(I),Zymobacterium(Z),Acuformis(A),Streptococcus(S1, S2),Ristella(R),Clostridium(C),Eubacterium(E),Pasteurella(P), andVeillonella(V); three facultatively anaerobic strains belonging to the generaActinobacillus(Ac),Lactobacillus(L), andStaphylococcus(St); and one yeast strain of the genusTorulopsis(T) were inoculated into adult male and female axenic mice fed either a commercial diet A or a semisynthetic diet B.Three strains (I, Z, St) did not establish in any "gnotoxenic" animals. One strain established only in animals fed diet B (S2). The average number of each of the other 10 strains is 10 to 100 times less in animals receiving diet B than in those given diet A. The microflora of the stomach and the small intestine is more variable and less abundant in mice fed diet B than in those receiving diet A. For strains A and C there is a net decrease in colon populations as related to those of the caecum or the feces, especially in mice receiving diet B.In the digestive tract of young "gnotoxenic" mice sacrificed before weaning, the facultatively anaerobic microflora is always established before the strictly anaerobic flora but does not change the establishment of the latter. Finally, the diet of the mother affects appreciably the establishment kinetics of strains L, St, and T in the young mice.

ISSN:0008-4166    

DOI:10.1139/m74-206

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The growth and respiration rates of a marine obligate psychrophile,Vibriosp., were determined in a complex medium using optical density and viable counts and a polarized oxygen-electrode system. Growth rate was optimal at 7C and decreased at 10C, the maximum temperature for growth. Respiration increased continually from 1to 10C. Both growth and respiration rates were highly sensitive to small changes in temperature. For example, rates at 4C were 1.8 and 4.4 times higher than at 1C for growth and respiration, respectively. Growth efficiencies were calculated as generations per hour divided by respiration rate. Results indicated that the growth efficiency of this bacterium was much greater at the lower temperature range of growth.

ISSN:0008-4166    

DOI:10.1139/m74-207

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

An electron-microscopic examination of selected species of the genusThiobacilluswas undertaken using the techniques of chemical fixation and freeze-etching. The architecture of the cells was typical of gram-negative bacteria. The multilayered cell envelope was revealed as a complex of smooth, rough, and particle-studded membranes. The particles which covered the outer plasma membrane (convex surface) appeared to contain a differentiated region which might permit a channeling between the exterior and interior of the cell. Inclusion bodies, including paracrystalline arrays, carboxysomes, and granules were present.

ISSN:0008-4166    

DOI:10.1139/m74-208

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The sequential development of intracellular antigens in cultured human embryonic fibroblasts infected with the AD-169 strain of cytomegalovirus was studied by means of antiglobulin, direct, and anticomplement immunofluorescent staining.Direct immunofluorescent staining, although less sensitive than the antiglobulin or anticomplement methods for the detection of early diffuse nuclear antigens, gave the clearest definition of the typical intracellular inclusions produced by cytomegalovirus.Quantitative complement fixation assays, carried out in parallel with anticomplement staining, showed that complement is fixed strongly by the intracellular antigens which develop in the late stages of infection.

ISSN:0008-4166    

DOI:10.1139/m74-209

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

California encephalitis virus (Snowshoe Hare strain) was isolated from these Alaskan sources: varying hare (snowshoe hare),Lepus americanusErxleben; indicator rabbit,Oryctolagus cuniculus(Linnaeus); varying lemming,Dicrostonyx rubricatus(Richardson); northern red-backed vole,Clethrionomys rutilus(Pallas); mosquitoes,Aëdesspp.; and blackflies,Simuliumsp. This virus has been confirmed as enzootic in east-central Alaska. Other arbovirus isolations were Silverwater virus, from hare-ticks,Haemaphysalis leporispalustris(Packard); Great Island virus and a virus of the Sakhalin group from bird ticks,Ixodes signatusBirula, from common murres,Uria aalge(Pontoppidan); and Northway virus, a hitherto undescribed member of the Bunyamwera group from a northern red-backed vole, from indicator rabbits, and from hematophagous Diptera. These findings include new host-records and extensions of the known geographic range of some of the viruses isolated.

ISSN:0008-4166    

DOI:10.1139/m74-210

出版商:NRC Research Press    

年代:1974

数据来源: NRC