摘要:

Affinity-purified antibodies specific for the purified, active periplasmic hydrogenase ofDesulfovibrio desulfuricanswere prepared. Immunodiffusion and enzyme-linked immunosorbent assay (ELISA) methods showed distinct differences between the native form of hydrogenase and the enzyme modified by heat, acid, active-site, and group-specific chemical treatments. The ELISA method indicated two zones of sensitivity, one for a native form of enzyme and another for irreversibly inactivated hydrogenase. The ELISA technique was also used to estimate the maximum specific activity of the enzyme in cell extracts. Immunoglobulins directed towards only the inactive form could not be obtained. A mixed immunoglobulin population directed towards both active and inactive forms of the enzyme was obtained by affinity chromatography on inactive hydrogenase – Sepharose. Immunological and enzymatic studies of the periplasmic hydrogenases in theDesulfovibriogenus showed strain dependence of the enzyme concentration in these microorganisms. The hydrogenases of two strains ofEscherichia coliand several other bacteria were examined and showed strong cross-reaction with the hydrogenase ofDesulfovibrio desulfuricans. It was found that the periplasmic and membrane-bound hydrogenases ofDesulfovibrio desulfuricansATCC 7757 differed in both enzymatic and immunological properties.

ISSN:0008-4166    

DOI:10.1139/m84-190

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

The mycotic flora of the scalp and interdigital areas of the hand and foot of 1296 apparently healthy human inhabitants of three Amazonian communities were surveyed by means of microscopic examination of epidermal scrapings and cultural isolation on Mycosel agar. No macroscopic or microscopic evidence of fungal infection was detected in any of our study subjects. From 133 (10%) individuals, 143 fungi representing 13 genera and 39 species were recovered. Yeasts constituted 85% of the fungi. Seventy-five percent of the isolates were fungi with pathogenic potential:Aureobasidium pullulans,Candida albicans,Candida guilliermondii,Candida parapsilosis,Candida stellatoidea,Candida tropicalis,Exophiala werneckii,Geotrichum candidum,Rhodotorula rubra,Torulopsis glabrata,Trichophyton tonsurans,Trichosporon cutaneum, andWangiella dermatitidis. The low frequency with which each species was represented resulted in a mosaic distribution of the fungi with respect to human anatomical sites and study areas. The lack of similarity in species composition beteen the human dermal mycoflora and soil mycoflora in the same study areas supports the conclusion that distinct yeast species occupy different environmental niches.

ISSN:0008-4166    

DOI:10.1139/m84-191

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Premature macroconidiation occurs at the tips of germ tubes elongated as presumptive conidiophores from macroconidia ofNeurospora crassaincubated at 37 °C in nitrogen-limited shaken cultures. The use of different nitrogen sources indicated that this differentiation process could be induced by ammonium deprivation. This microcycle conidiation was also promoted by carbon deprivation and found not to be strain specific. At 25 °C, microconidia were produced in nutrient-limited shaken cultures. The results present evidence that microcycle conidiation inN.crassacan be obtained by simple manipulation of the conditions of culture.

ISSN:0008-4166    

DOI:10.1139/m84-192

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Liposomes labelled with125I-labelled albumin were used as carriers for the introduction of albumin into vegetative and aggregation competent cells ofDictyostelium discoideum. The subcellular distribution of albumin and its degradation products was followed. The results show that 44 and 67% of the radioactivity incorporated by vegetative and aggregation competent cells, respectively, was found in soluble form in the cell. These figures fall to 26 and 34% in the presence of metabolic inhibitors with a concomitant increase of membrane-bound radioactivity. Differences in the mode of liposome–cell interaction in the two stages of development of the organism and the possibility that metabolic inhibitors may operate at the site of the vacuole–liposome fusion step are discussed.

ISSN:0008-4166    

DOI:10.1139/m84-193

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Superoxide dismutase (SOD), catalase (CAT), and peroxidase (PER) activities were studied in ammonium-grown and N2-fixing batch cultures ofAzospirillum brasilenseSp7. PER activity, as measured usingo-dianisidine or 3,3′-diaminobenzidine as the H donor, was not significant in most growth conditions. SOD activity increased in response to higher O2concentrations but was also present in cells grown anaerobically with nitrateor nitrous oxide (N2O) as electron acceptor. CAT activity increased at lower O2concentrations and was highest in cells grown anaerobically withas electron acceptor. Polyacrylamide gel electrophoresis of cell-free extracts revealed only one band of SOD activity under each of the physiological conditions employed, compared with three for aerobically grownEscherichia coliK12. This band proved to be iron-containing SOD (FeSOD) on the basis of inhibitor sensitivity.

ISSN:0008-4166    

DOI:10.1139/m84-194

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

ThirtyHaemophilusstrains and sixActinobacillusstrains, all of porcine origin, were examined for their biochemical reactivity on API 20E and API ZYM test strips using dense cell suspensions (supplemented with NAD as appropriate) as strip inocula. When combined with a test for V-factor dependency, the use of both strips allowed adequate differentiation of closely related organisms. Numerical taxonomic analysis of the data demonstrated that the majority of the haemophili and actinobacilli studied could be placed in one of four major clusters; these clusters contained, respectively, theH.pleuropneumoniae–A.pleuropneumoniaestrains, theH.parasuisstrains, strains belonging toHaemophilustaxon "minor group," and strains belonging to an unusual group of mannitol-positive, urease-negative haemophili. A representative ofHaemophilusspecies taxon C and an unusualActinobacillusisolate appeared to be comparatively unrelated to organisms in the four major clusters. Although it may, on occasion, be difficult to place an unusual isolate in any one particular group, owing to the uncertain taxonomy of some of these organisms, it is concluded that API test strips can serve as useful tools for the characterization and differentiation of porcine haemophili and actinobacilli.

ISSN:0008-4166    

DOI:10.1139/m84-195

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Cell wall peptidoglycan synthesis inEscherichia coliis under stringent control. During amino acid deprivation, peptidoglycan synthesis is inhibited inre1A+bacteria but not inre1Amutants. The relaxed synthesis of peptidoglycan by amino acid deprivedre1Abacteria was inhibited by Several β-lactam antibiotics at concentrations which inhibited cell elongation in growing cultures suggesting that the transpeptidase activity of penicillin-binding protein (PBP-1B) was involved in this process. Structural studies on the peptidoglycan also indicated the involvement of transpeptidation in relaxed peptidoglycan synthesis. The peptidoglycan synthesized during amino acid deprivation was cross-linked to the existing cell wall peptidoglycan, and the degree of cross-linkage was the same as that of peptidoglycan synthesized by growing control cells. The relaxed synthesis of peptidoglycan was also inhibited by moenomycin, an inhibitor of thein vitrotransglycosylase activities of PBPs, but the interpretation of this result depends on whether the transglycosylases are the sole targets of moenomycinin vivo. Most of the peptidoglycan lipoprotein synthesized by histidine-deprivedre1A+bacteria was in the free form as previously reported, possibly because of the restriction in peptidoglycan synthesis. In support of this proposal, most of the lipoprotein synthesized during histidine deprivation ofre1Amutants was found to be covalently linked to peptidoglycan. Nevertheless, the peptidoglycan synthesized by amino acid deprivedre1Abacteria was apparently deficient in bound lipoprotein as compared with peptidoglycan synthesized by normal growing control bacteria suggesting that the rate of lipoprotein synthesis during amino acid deprivation may be limiting.

ISSN:0008-4166    

DOI:10.1139/m84-196

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Droplets of exudate from rhizomorphs ofArmillaria mellea(Vahl ex Fr.) Kummer, grown on carrot agar, grew larger in size and darkened with age. The exudate was found to contain free amino acids, protein, and inorganic elements, but no oxalic acid was detected. β-Glucosidase, peroxidase, polyphenoloxidase, and acid and alkaline protease activities were also detected. Gel electrophoresis was used to analyze the dark brown exudate. A single dark brown band was obtained using the disc gel procedure, whereas many brown bands were formed using the isoelectric focusing technique.

ISSN:0008-4166    

DOI:10.1139/m84-197

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Microbiological- and food-grade beef extracts, protein hydrolytic, enzymatic and autolytic digestion products, and whole protein materials were examined for their potential effectiveness for eluting adsorbed enteroviruses from membrane filters with observed efficiencies ranging from less than 1 to 69%. Concentration of enteroviruses from solutions of these protein and protein-derived products by organic flocculation ranged in efficiency from 2 to 125%. Both elution and concentration were dependent upon virus type, as well as nature, source, and production lot of the material being tested. Determining the efficiency of virus concentration was complicated by virus aggregation and apparent virus inactivation by low pH. Effectiveness of concentrating viruses by organic flocculation from solutions prepared with the various test materials seemed independent of the amount of precipitate produced during the flocculation procedure. Quality assurance tests were proposed by which solutions prepared from beef extracts, whole protein, and protein-derived materials could be evaluated for use in eluting adsorbed viruses from membrane filters and for concentrating viruses by organic flocculation. Food-grade beef extract seemed equal to microbiological-grade beef extract in terms of both virus elution and concentration. Several of the nonbeef extract materials evaluated were as effective as beef extract for virus concentration, but were less effective for virus elution.

ISSN:0008-4166    

DOI:10.1139/m84-198

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

The bactericidal capability of murine peritoneal polymorphonuclear neutrophils against virulent and nonvirulentSalmonella typhimuriumwas examined in anin vitrosystem. Although preincubation of the bacteria in specific murine antiserum elicited greater chemiluminescence from phagocytizing neutrophils than did incubation in normal murine serum, antiserum did not enhance ingestion, as less than 5% of the challenge was taken up by neutrophils under any of the conditions studied. Nonvirulent salmonellae showed a transient decrease in viable numbers early duringin vitroincubation with or without intact neutrophils. Virulent salmonellae, however, were able to multiply without a lag period except when these bacteria were pretreated with antiserum and incubated in association with intact murine neutrophils. Results of thesein vitrostudies suggest that the murine polymorphonuclear neutrophil and antisalmonella antibody must act together to effect neutrophil-associated bactericidal activity against virulent salmonellae, and thus, that the neutrophil alone does not play a major role in the protection of unvaccinated, sensitive mice from disease caused byS.typhimurium.

ISSN:0008-4166    

DOI:10.1139/m84-199

出版商:NRC Research Press    

年代:1984

数据来源: NRC