摘要:

Mycelia ofFusarium oxysporumf. sp.lycopersiciaccumulatedL-methionine by an energy-dependent process, and the energy required for uptake may be derived from either respiration or glycolysis. The pH optimum for transport was 4 and the temperature optimum was 35 °C. The apparentKmfor methionine uptake was 2.5–3.3 μMand theVmaxwas 0.24–0.30 nmol∙min−1∙mg dry weight−1.S-adenosylhomocysteine (Ado-Hcys) was the major metabolic product of methionine althoughS-adenosylmethionine (Ado-Met), homocysteine (Hcys), and an unidentified metabolite (compound X) were also detected. The failure to demonstrate efflux of accumulated methionine in the presence of the uncoupler 2,4-dinitrophenol or excess unlabeled methionine was probably due to the fact that methionine was rapidly metabolized within the cells.Acidic and basic amino acids, and those amino acids having less than a four-carbon chain, did not inhibit methionine uptake. The rate of uptake of methionine, which was greatest in log phase mycelia, decreased substantially as the cells entered the stationary ph

ISSN:0008-4166    

DOI:10.1139/m81-115

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Microorganisms in spent steamed mushroom compost and its dust were enumerated, isolated, and identified. Some phase II (indoor composting) compost samples were also examined. Steaming of spent compost resulted in a 70–76% reduction in microbial numbers. Total counts made with compost infusion agar were approximately two logs greater than those for nutrient agar.The most common bacterial isolate wasBacillus licheniformis. The most common actinomycete isolates wereStreptomyces diastaticusandThermoactinomyces vulgaris. Other actinomycete isolates includedStreptomyces albus,Streptomyces griseus,Thermoactinomyces thalpophilis,Thermomonospora chromogena, andThermomonospora fusca.The most common fungal isolates wereAspergillus fumigatusandHumicola griseavar.thermoidea. Other fungal isolates includedAspergillus flavus,Aspergillus nidulans,Aspergillus terreus,Aspergillus versicolorgroup,Chrysosporium luteum,Mucor spp.,Nigrosporaspp.,Oidiodendronspp.,Paecilomycesspp.,Penicillium chrysogenum,Penicillum expansum,Trichoderma viride, andTrichurusspp.

ISSN:0008-4166    

DOI:10.1139/m81-116

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The effect of aspirin (ASP), chlorpromazine (CPZ), diphenoxylate (DP), ethylene glycol tetraacetate (EGTA), hydrocortisone (HC), loperamide (LPA), methylprednisolone (MP), phenotolamine mesylate (PTM), propranolol (PR), and trifluoperazine (TPZ) on the secretory activity induced byEscherichia coliheat-stable (ST) enterotoxin in infant mice was studied. LPA and DP, which are used therapeutically for diarrhea, did not inhibit the effect of ST enterotoxin; MP and HC, known inhibitors of cholera enterotoxin, and two adrenergic agents (PR and PTM) had no effect on ST-induced secretory activity. TPZ, EGTA, ASP, and CPZ caused a significant (P < 0.05) decrease in the secretory activity induced by ST enterotoxin. CPZ, EGTA, and TPZ inhibited secretory activity induced by 8-bromoguanosine 3′5′-cyclic monophosphoric acid (8-BrcGMP), a cGMP analog.

ISSN:0008-4166    

DOI:10.1139/m81-117

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Transformation ofPseudomonas syringaestrains with plasmid DNA occurs at a frequency of 1 × 10−3to 4 × 10−9per recipient cell, depending on the strain, plasmid, and conditions for transformation. R plasmids used successfully in transformation were pR0161 (26 × 106molecular weight) and RSF1010 (5.5 × 106molecular weight). Transformation involved growing the recipient cells to approximately 8 × 108colony-forming units per millilitre in 50 mL of a nutrient broth. After washes with a 150 mMCaCl2– 10% (v/v) glycerol mixture, cells were concentrated 20-fold and resuspended in this solution. The cells then were incubated with purified plasmid DNA for 1 h prior to a heat pulse at 45 °C for 2 min. Transformants were selected by antibiotic resistance and plasmid presence was verified by agarose gel electrophoresis. With plasmid pCG131 (34 × 106molecular weight; putatively associated with syringomycin production), transformation of syringomycin-negativeP.syringaestrains that contained no detectable plasmid or were cured of pCG131 was unsuccessful, whether the plasmid was used alone or in combination with either pR0161 or RSF1010.

ISSN:0008-4166    

DOI:10.1139/m81-118

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Screening for mycotoxin production byChaetomiumspp. and related fungi on rice culture was conducted by a combination of cytotoxicity tests using HeLa cells and thin-layer chromatography. Producers of sterigmatocystin,O-methylsterigmatocystin, chaetochromin, chaetocin, chetomin, cochliodinols, and mollicellin G were found and the taxonomic significance of these findings is discussed.

ISSN:0008-4166    

DOI:10.1139/m81-119

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Trimethylarsine oxide, a probable intermediate in the biological transformation of arsenate, was reduced to volatile trimethylarsine byCandida humicola. A simple assay for the rate of trimethylarsine production from trimethylarsine oxide by the fungus was developed. The optimum pH for the reduction was determined as 5.1–5.2, and the optimum temperature was 40 °C. The rate of reduction was directly proportional to cell concentration and followed Michaelis–Menten type kinetics. There was almost no trimethylarsine produced by heated or broken cells. The reaction was inhibited by a number of electron transport inhibitors and uncouplers of oxidative phosphorylation including cyanide, azide, and 2,4-dinitrophenol. The rate of reduction was modified by arsenate, methylarsonate, dimethylarsinate, selenate, and tellurate. Preincubation of cells with trimethylarsine oxide increased the rate of reduction 69-fold; this increase in activity was blocked if the cells were incubated with the protein synthesis inhibitor cycloheximide.

ISSN:0008-4166    

DOI:10.1139/m81-120

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The hyphal walls ofAgaricus bisporusandAgaricus campestrisfruiting bodies were isolated and purified. Quantitative analyses revealed that these walls consisted mainly of carbohydrates (78.3–79.2%), lipids (9.9–10.1%), and proteins (8.7–10.2%). The major components of carbohydrate polymers were glucose,N-acetylglucosamine, and glucosamine. In addition, small quantities of galactose and mannose have been found.N-Acetylglucosamine and glucosamine were identified chemically and enzymatically, and also by infrared spectrum and X-ray diffraction analyses, as chitin and chitosan. Neutral polysaccharides include an alkali-soluble glucan with α(1–3) linkages and a β(1–3)- and β(1–6)-linked glucan.The lipid fractions in both hyphal walls contained precursors of melanin, this pigment being largely represented inAgaricusspore walls. Amino acids analyses indicate that structural wall proteins were very similar in both organisms.In electron micrographs of ultrathin sections of hyphae no distinct layering was apparent in contrast with spore walls of the same organism, which show two wide well-defined layers.

ISSN:0008-4166    

DOI:10.1139/m81-121

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The primaryin vitrocultures from lepromata of mice or rats previously infected with the Hawaiian strain ofMycobacterium lepraemuriumwere obtained on Ogawa egg-yolk medium at 34 °C in approximately 90 days of incubation. Optimal growth of subcultures was achieved in 40 to 60 days of incubation and such cultures were used to test their pathogenicity in animals. Thein vitrogrown subcultures provoked in mice subcutaneous lepromata identical to those produced by thein vitrogrownM.lepraemurium. Also, mice infected subcutaneously and intravenously with thein vitrogrown subcultures developed lesions in livers, spleens, and kidneys similar to those of mice infected with the mouse passage murine leprosy bacilli. Microscopically and histopathologically, the acid-fast bacilli derived from organs infected with thein vitroorin vivogrown cultures were indistinguishable from each other.

ISSN:0008-4166    

DOI:10.1139/m81-122

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Membrane vesicles ofBacillus subtilisW23 actively transport the C4and C5dicarboxylates of the tricarboxylate cycle by system(s) of relatively high affinity for their requisite substrates (Km4–53 μM). Glutamate and succinate binding activities were readily solubilized from membrane vesicles by nonionic detergents, particularly by Lubrol WX. From this extract, glutamate binding activity was highly enriched by affinity chromatography on phloroglucinol-expanded Sepharose-6B to whichL-aspartate was coupled via divinylsulfone. Another protein (41 000 molecular weight), which bound bothL-glutamate andL-malate, was purified from affinity columns to which eitherL-glutamate orL-malate had been coupled via bisdiglycidyl ether. This protein bound labelledL-malate as well asL-glutamate with affinities similar to those seen with membrane vesicles (Kd's 8 μML-malate and 52 μML-glutamate).

ISSN:0008-4166    

DOI:10.1139/m81-123

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Phosphonoacetate was found to be an effective inhibitor of the replication and cytopathic effects (CPE) associated with Anatid herpesvirus (AHV) infections in avian cells. In low multiplicity of infection (MOI) (10−3or less) infected Pekin duck and chicken fibroblast cultures, the dosage required for a 50% plaque reduction was approximately 20 μg/mL. The amount of the inhibitor needed for complete prevention of CPE was found to be MOI dependent with up to 190 μg/mL required at a MOI of 1.1. Delayed addition of phosphonoacetate to AHV-infected cultures resulted in differing CPE. When added before 25 h postinfection, the CPE were largely prevented. Added between 25 and 40 h postinfection, the CPE consisted of nonproductive, nonperforate focal areas containing viable and nonviable cells. The focal areas did not appreciably increase in size or number in the continued presence of phosphonoacetate, were chromophilic, and tended to be replaced by morphologically normal cells, provided the presence of phosphonoacetate was continued. Maintaining phosphonoacetate in the presence of infected cultures for periods of 7 days or longer resulted in curing and a complete loss of infectious virus in the medium and in cell lysates.

ISSN:0008-4166    

DOI:10.1139/m81-124

出版商:NRC Research Press    

年代:1981

数据来源: NRC