ISSN:0008-4166    

DOI:10.1139/m82-001

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Solid-state and liquid-state fermentations were carried out to evaluate the effect ofRhizopus oligosporuson the trypsin inhibitor of denatured black gram grits. The trypsin inhibitor fraction was released into the supernatant, attaining a maximum concentration by 72 h of incubation, as indicated by its activity. The increase in trypsin inhibitor activity was approximately threefold in solid-state fermentation and approximately fivefold in liquid-state fermentation. Results indicated that the spore-free culture filtrate prepared fromR.oligosporuscontained "releasing factor(s)" which were effective on black gram grits. The effect of the spore-free culture filtrate on black gram trypsin inhibitor suggests the presence of a factor in the culture filtrate which inactivates the trypsin inhibitor fraction.

ISSN:0008-4166    

DOI:10.1139/m82-002

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

The EFDL strain of Bluegill virus, a fish virus, was grown in a Bluegill Fry cell line (BF-2) in medium containing [3H]uridine or [32P]orthophosphate. This virus was purified from the cellular material by precipitation with PEG 6000 followed by isopycnic centrifugation in a Percoll gradient. As calculated from reconstruction experiments, only 8.5 and 0.5%, respectively, of the host proteins and the host RNA were recovered with the viral band, whereas the recovery of viral infectivity was approximately 20%. Electron microscopy of the viral band showed mostly intact virus particles. The nucleic acid extracted from purified virus was found to have the following properties: (i) it migrated homogeneously during electrophoresis at the rate expected from a single-stranded nucleic acid of molecular weight 2.17 × 106, (ii) it sedimentated as a single molecular species when analyzed by velocity centrifugation in sucrose gradients,(iii) it banded in a neutral Cs2SO4gradient at a density of 1.69 g/cm3as expected for single-stranded RNA, (iv) its base composition is that of a single-stranded RNA molecule: 14.89% C, 12.77% A, 37.03% U, and 35.23% G. The nucleic acid of Bluegill virus thus appears to be a single-stranded RNA molecule of approximately 2.17 × 106molecular weight.

ISSN:0008-4166    

DOI:10.1139/m82-003

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Two of six tested strains ofHyphomicrobiumrespired on benzaldehyde with higher rates than on formaldehyde, and three strains with equal or lower rates, whereas one strain,HyphomicrobiumX, showed almost negligible respiration on benzaldehyde. Various substituted benzaldehydes stimulated oxygen consumption to lower rates than benzaldehyde itself in active strains. All strains contained multiple forms of dye-linked aldehyde dehydrogenase, as evident from polyacrylamide gel electropherograms of cell-free extracts and activity tests on the gels with nitroblue tetrazolium. All bands of this enzyme reacted more strongly with benzaldehyde than with formaldehyde in all strains. On gels of some strains additional bands appeared with benzaldehyde as the enzyme substrate.HyphomicrobiumX again displayed the lowest activity of this enzyme on the gels. A new band of this enzyme appeared on gels of strain ZV 580 after growth on methylamine, when tested in this respect. NAD-dependent secondary alcohol dehydrogenase was present on gels of three strains, which respired on 2-propanol.Difference spectra and observation of the degree of reduction of ubiquinone and cytochromesbandcof two strains indicated that the electrons from benzaldehyde oxidation were transferred to cytochromec.The results are discussed with regard to the significance of dye-linked aldehyde dehydrogenases with broad substrate specificity for the catabolism and oligocarbophilic growth ofHyphomicrobiumand the taxonomic relevance of the aldehyde dehydrogenase pattern observed on polyacrylamide gel electropherograms.

ISSN:0008-4166    

DOI:10.1139/m82-004

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

1-Chloronaphthalene and 2-chloronaphthalene were metabolized by pseudomonads able to degrade naphthalene, but the chloronaphthalenes did not support growth. Their metabolism probably proceeded by the pathway for naphthalene metabolism, for they were not metabolized by cured derivatives of strains in which naphthalene metabolism is normally determined by a plasmid, the metabolism of 2-chloronaphthalene was accompanied by the accumulation of a chloro-2-hydroxy-6-oxohexadienoate, and 4- and 5-chlorosalicylate were converted to this compound and themselves induced enzymes for naphthalene and chloronaphthalene metabolism. In one strain, ATCC 17483, it was possible to show that during growth on succinate in the presence of chloronaphthalenes the enzymes of naphthalene metabolism were induced. Failure of 2-chloronaphthalene to support growth was probably associated with the very slow metabolism of the chloro-2-hydroxy-6-oxohexadienoic acid or possibly with the toxicity of this compound or its metabolites.

ISSN:0008-4166    

DOI:10.1139/m82-005

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Electron microscopic examinations ofBacillus subtiliscells revealed that relatively high concentrations of carbon sources blocked sporulation at stage 0 in most cells. Both nalidixic acid and novobiocin blocked sporulation at stage 0. The cells treated with acridine orange showed the morphology of stage IV 5 h after the end of exponential growth, but no further progression was observed. Mutants that are able to sporulate in the presence of these agents had the characteristic morphological changes observed in uninhibited cultures.

ISSN:0008-4166    

DOI:10.1139/m82-006

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Morphologically abnormal sclerotia ofSclerotinia sclerotiorumwere found in samples collected from diseased sunflower head and stem tissues. The frequency of abnormal sclerotia in 22 samples varied from 0 to 30%. Whereas the surface of normal sclerotia is macroscopically smooth and the medullary tissue is uniformly pale white, the surface of abnormal sclerotia is wrinkled and the center of the medullary tissue is brown or amber. The degree of abnormality varies among sclerotia. Some have a small discolored center surrounded by a thick medullary layer, whereas others have a large discolored center encircled by a thin medulla. Abnormal sclerotia also differ from normal ones in viability on culture media as well as in pathogenicity on sunflowers.

ISSN:0008-4166    

DOI:10.1139/m82-007

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Microbial populations associated with the amphipodBoeckosimus affiniswere examined using scanning electron microscopy and by detailed characterization of viable isolates. Bacterial populations were observed on food particles in the midgut, on the anal plates, and on faecal matter, but no bacteria were observed on the outer surfaces or on the gut lining of the amphipod. The dominant bacterial populations associated with the amphipods were in theVibrio–Beneckeagroup. Exposure to petroleum hydrocarbons resulted in a decreased dominance of the vibriolike bacterial populations associated with the amphipods. During captivity (without feeding) there were successional changes in the bacterial populations associated with the amphipods; the diversity of the bacterial community increased and the bacterial populations became less stringent in their physiological and nutritional requirements.

ISSN:0008-4166    

DOI:10.1139/m82-008

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

The effects of theClostridium difficiletoxin were examined in HeLa and mouse adrenal tumor (MAT) cells. Cytotoxicity was evaluated by vital dye exclusion and51Cr release. In both HeLa and MAT cells,C.difficiletoxin caused rounding of virtually 100% of cells. This rounding was distinguishable from rounding produced by theEscherichia coliheat-labile enterotoxin (LT): (1) LT was inactive in HeLa cells; (2) in MAT cells,C.difficiletoxin produced uniformly rounded cells, while LT-rounded cells usually had cytoplasmic extensions and a regular background of flattened cells. InC.difficiletoxin affected HeLa cells, there were <2 mitotic figures per 1000 cells compared with 15–18 in controls.Clostridium difficiletoxin treated HeLa cells showed <10% cytotoxicity in 24 h and no more than 30% by 74 h, similar to control cells. However, paralleling the suppression of mitotic figures, cell multiplication was inhibited inC.difficiletoxin treated cells when subcultured in a short-term (72 h) assay compared with up to a 500% increase in control cells. This inhibition was also seen in a 6-week cloning assay in whichC.difficiletoxin treated cells had a cloning efficiency of <1% compared with approximately 10% in controls. We conclude that the major effect of theC.difficiletoxin is inhibition of growth rather than immediate cell death. The relationship of this growth inhibition to colitis remains to be elucidated.

ISSN:0008-4166    

DOI:10.1139/m82-009

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Group E streptococci were grown in a modification of a chemically defined medium (CDM) originally formulated for streptococci of group A. Ten of 12 strains studied produced greater or equal cultural densities and growth rates in CDM than in the complex medium (Todd–Hewitt broth). All strains produced similar amounts of group antigen in both media. Eight strains of demonstable serotype produced comparable amounts of type antigen in both media. Cells grown in CDM were less resistant to phagocytosis than those grown in the complex medium, but all strains produced antiphagocytic factor when cultured in either medium to which 10% porcine serum had been added.

ISSN:0008-4166    

DOI:10.1139/m82-010

出版商:NRC Research Press    

年代:1982

数据来源: NRC