摘要:

Studies of heterotrophically and autotrophically grownThiobacillus novellas(A.T.C.C. 8093) showed several differences in cell structure. The envelope of the heterotrophically grown cell appeared as a homogeneous three-layered structure. The envelope of the autotrophically grown cell under the same fixing and staining procedure also appeared as a three-layered structure; however, differences were evident in the outermost layer of the two envelopes. Chemical analysis and specific staining procedures suggested that globules present in the heterotrophic cells were made up of polysaccharide.

ISSN:0008-4166    

DOI:10.1139/m69-116

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The clinical bacteriologist faces a taxonomical problem concerning a group of Gram-negative, non-chromogenous, oxydase-negative bacilli, isolated on MacConkey agar and which produce no modification of Kligler medium (glucose, lactose, SH2).A review of the literature on the subject is made and allows the authors to adopt M. Piéchaud's nomenclature, which uses the termMoraxellaand divides this genus in two groups:group I, oxydase-positive, is briefly discussed;group II, oxydase-negative, contains two species:(a)Moraxella lwoffi, which is synonymous withMima polymorpha,Achromobacter, andAcinetobacter lwoffi,(b)Moraxella glucidolytica, also termedHerellea vaginicola, B5W,Bacterium anitratum,Achromobacter, andAcinetobacter anitratum.Table III is suggested for the differential diagnosis of these Gram-negative bacteria of medical interest, which do not belong to the family Enterobacteriaceae. This diagram also indicates the position that the authors thinkMoraxella,Achromobacter, andAcinetobactershould have in bacterial taxonomy.

ISSN:0008-4166    

DOI:10.1139/m69-117

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The chemical composition of the cell envelope of the bacillary form ofStreptobacillus moniliformiswas investigated to determine if there were any unusual features which might account for the ability of this organism to produce L forms spontaneously. A procedure was developed for the preparation of particles of the cell envelope using sonic oscillation to disrupt the cells. Particles of the cell envelope ofE.coliB prepared by this method were comparable to those preparations obtained by other methods. The percentages of the major chemical components of the cell envelope ofS.moniliformiswere 64% protein, 28% lipid, and 6% carbohydrate. Cell envelope preparations made fromE.coliB contained 66% protein, 18% lipid, and 10% carbohydrate. All common amino acids were present in hydrolysates of the cell envelope ofS.moniliformiswith the exception of cysteine. The monosaccharides detected in hydrolysates of the cell envelope ofS.moniliformiswere glucose, galactose, heptose, glucosamine, and muramic acid. The amounts of glucosamine and muramic acid (and presumably therefore mucopeptide) present in the cell envelope ofS.moniliformiswere much less than those amounts detected in the cell envelope ofE.coliB. It is suggested that the low content of mucopeptide may be related to the ability ofS.moniliformisto produce L forms spontaneously.

ISSN:0008-4166    

DOI:10.1139/m69-118

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Under clearly defined conditions one-step acquisition of viomycin resistance by a normally effective strain ofRhizobium melilotiresulted in one-step acquisition of ineffectiveness in nitrogen fixation, which probably occurred with a one-gene change in theR.melilotigenome. Two-step mutants retained their ability to produce root nodules but such nodules also were ineffective. Increased sensitivity of the viomycin-resistant mutants to glycine andD-alanine was not noted. Bacteroids were not seen in nodules formed by the viomycin-resistant mutants on their homologous host plant. Nitrogenase activity was not detected, by acetylene reduction, in detached ineffective nodules, whereas effective nodules formed 10.6 μmoles of ethylene per hour per gram of nodules. Growth of the effective parent strain in a low concentration of viomycin resulted in elongation and swelling of the cells so that they appeared as artificially produced bacteroids. Viomycin-resistant mutants did not undergo this transformation. Antigens could be readily extracted by hot- and cold-saline extraction of wet packed cells of both resistant and sensitive cultures but antigenic differences, which may have indicated cell wall differences, were not noted.

ISSN:0008-4166    

DOI:10.1139/m69-119

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

ATrichoderma viride, aPenicillium frequentons, and anAspergillus fumigatuswere isolated from fulvic acid enrichment cultures. These and a white rot fungus,Poria subacida17780, were tested for their ability to decompose fulvic acids (FA) in liquid cultures. All of the organisms tested were totally inhibited by the presence of FA at 1% concentration. The soil isolates brought about transformation of the FA to humic acids. In 48 h, thePoria subacidaused 66% of the FA (0.05%) present as the sole source of carbon in static replacement culture, and up to 45% in 24 days in a static culture. Loss of FA was measured by photometry and confirmed by determination of the carbon content of FA precipitated as iron complex before and after attack. Phenol oxidase of thePoria subacidaapparently had no role in degradation of the FA but could darken the color of a well-aerated medium through oxidative transformation of FA products.Preliminary studies with cell-free preparations of theP.subacidaindicated that the breakdown is initiated by an enzyme present in particulate fraction of the cells and this activity is extended or facilitated by a factor present in the soluble fraction of the cells. FA-cleaving enzymes(s) may thus be available for use in controlled FA degradation studies aimed at characterizing soil humus.

ISSN:0008-4166    

DOI:10.1139/m69-120

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The erythrocyte-sensitizing ability (ESA), as measured by the bis-diazotized-benzidine hemagglutination test, was determined for the extractable and culture filtrate antigens of three strains of mycobacteria (H37Rv, H37Ra, and BCG). The ESA of the precipitated and supernatant fractions obtained from these preparations by precipitation with ammonium sulfate, was found to vary according to the age of the cultures: the concentration of antigens decreased in the bacillary extracts and increased in the corresponding culture filtrates with the aging of the mycobacterial cultures.The variation in the antigenic composition of bacterial extracts and of culture filtrates during the growth cycle was also demonstrated by immunodiffusion techniques in agar gel. However, all extractable antigens of a givenMycobacteriumdid not appear in the culture filtrates.

ISSN:0008-4166    

DOI:10.1139/m69-121

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Serratia marcescenswas found to be the most active organism of 100 tested for the production of chitinase.Enterobacter liquefaciensproduced nearly as much enzyme. Under optimal conditions high yields of chitinase were obtained in 4–6 days. TheS.marcescensenzyme system is extracellular and is composed of an endochitinase, a chitobiase, and a factor (CH1) required for the hydrolysis of "crystalline" chitin. As such, it closely resembles the cellulase system ofTrichoderma viride, and differs from those chitinolytic systems which act only on degraded forms of chitin. The absence of other hydrolytic enzymes in theS.marcescensfiltrates makes this a useful system for determining the role of chitinase as a lytic agent.

ISSN:0008-4166    

DOI:10.1139/m69-122

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Endo-β-glucanase was detected inHanseniaspora valbyensisandHanseniaspora uvarum. The extracellular enzyme activity ofH.valbyensiswas maximal with vigorous aeration at 30 C in a complete mineral medium with glucose and 0.2 MNa-succinate buffer. The enzyme concentration was lower when the buffer was 0.05 MNa-succinate. The use of a variety of carbon sources, including yeast cell walls, failed to induce higher enzyme activities. The enzyme was purified 34-fold from the culture fluid ofH.valbyensis. The purified enzyme had a broad pH optimum between pH 3.5 and 4.5. Among the known β-glucan homopolymers, only laminarin (β-1 → 3 bonds) was hydrolyzed by the enzyme. TheKmfor laminarin was 0.11 mg/ml and the Vmaxwas 0.835 μmoles glucose equivalents/min mg protein. No action was detected with laminaribiose, laminaritriose, or oat glucan. Laminaritetraose, however, was hydrolyzed slowly in a random pattern. These results suggest the requirement for three consecutive β-1 → 3 bonds for activity.

ISSN:0008-4166    

DOI:10.1139/m69-123

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Three isolates ofTrichoderma viridePers. ex Fries were grown in liquid cultures. The isolates grew best on media containing glucose, sucrose, cellobiose, and mannitol.Asparagine and ammonium nitrate proved to be the best sources of nitrogen for the three isolates although isolate 1503 did not show any significant preferences for the five sources of nitrogen. The amounts of carbon and nitrogen in the basal medium significantly influenced the growth of the three isolates. However, the addition of asparagine alone did not produce a better growth than in the control. There is no correlation between sporulation and dry weight of culture, the amounts of carbon in the medium, and C/N ratio. Implications of the findings are briefly discussed.

ISSN:0008-4166    

DOI:10.1139/m69-124

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

When actively growing cells ofEscherichia coli15T−were treated with the new antibiotic myxin, the effects produced by the antibiotic varied, depending on the concentration. With a concentration of 1 μg/ml, the action was bacteriostatic for the first 60 min exposure. Cell division was inhibited but there was no apparent effect on macromolecular synthesis as evidenced by the formation of filamentous cells. At higher concentrations (3 and 5 μg/ml), myxin was bactericidal although some cell elongation occurred at the 3 μg/ml level. Microscopic examination of cells treated with 3 and 5 μg/ml for 30–45 min indicated the presence of vacuolated areas which thin section studies revealed as intracellular ramifications of the plasma membrane. Protoplasts of cells grown in the presence of 5 μg/ml myxin were enlarged or rapidly lysed even after as little as 15 min exposure. Myxin has no effect on the cell surface of control protoplasts. No abnormal development of the plasma membrane was noted in the elongated cells formed in the presence of 1 μg/ml myxin. Except for the lack of septation during the first 60 min, the filamentous forms appeared normal with well-defined nuclear bodies distributed throughout the cell.

ISSN:0008-4166    

DOI:10.1139/m69-125

出版商:NRC Research Press    

年代:1969

数据来源: NRC