摘要:

It was demonstrated that a potent and specific non-infective diagnostic western equine encephalomyelitis virus antigen can be readily prepared in quantity by gamma irradiation of the infective allantoic fluid, followed by its concentration and lyophilization for stable storage. This antigen is easier to prepare in bulk and involves less exposure of personnel to the infective agent than the antigen prepared from suckling mouse brains.

ISSN:0008-4166    

DOI:10.1139/m68-171

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Neutral and polar lipids in an extract ofPullularia pullulanswere separated by a single silicic acid column. Of the total lipid content, 74% was found to be neutral lipids, on the average, and 26% was polar lipids. Gas chromatography of methyl esters of the fatty acids showed the presence of 15 acids, of which 59.2% were unsaturated. The most abundant unsaturated acid was C18monounsaturated (41.9%) and the most abundant saturated acid wasC16(30.8%). Gas chromatography and thin-layer chromatography revealed the presence of ergosterol, stigmasterol, and possibly squalene. Straight chain, branched chain, and saturated and unsaturated hydrocarbons were also found by gas chromatography. Trehalose was isolated and evidence suggests that it was esterified with one or more fatty acid residues.

ISSN:0008-4166    

DOI:10.1139/m68-172

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Actively growing cells ofArthrobacter pascenswere sectioned and examined by electron microscopy. The cell wall, plasma membrane, mesosomes, and mode of division are typical of Gram-positive organisms. Mature mesosomes appear as a series of uniform, convoluted tubules (280–325 Å in diameter) bounded by a single unit membrane. The development of the mesosomes was followed throughout the growth cycle by thin section and negative staining techniques. Coccoid stationary phase cells (48 hours) contained a large number of simple membranous inclusions. On transfer to fresh media the cells undergo a 4-hour predivisional lag during which time the cells enlarge to pleomorphic rods. During this period only one to three developing mesosomes are noted per cell. By 4 to 5 hours when active division has been initiated, only mature vesiculotubular mesosomes are present, primarily at or near the site of septum formation. Rudimentary membrane inclusions begin to reappear at the end of active growth (7 to 8 hours) corresponding to the time of medium limitation. During the reversion of the pleomorphic rods to the coccoid stage, mature mesosomes disappear and only rudimentary profiles remain. The fact that the period required for the development of mesosomes coincides with the predivisional lag period ofA.pascenssuggests a definite role of these membranous intracellular organelles in the division process.

ISSN:0008-4166    

DOI:10.1139/m68-173

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

A wide range in growth responses was obtained by two isolates each ofSclerotinia trifoliorumErikss. andS.sclerotiorum(Lib.) d By. in stationary culture in a synthetic liquid medium containing a number of nitrogen sources representing both organic and inorganic forms. Good sources of nitrogen were casein hydrolysate,L-proline,DL-asparagine,L-arginine,L-glutamic acid,L-aspartic acid,L-histidine,L-alanine, ammonium chloride, ammonium nitrate,L-tryptophan, ammonium sulfate, andDL-phenylalanine. Poor nitrogen sources included potassium nitrite, sodium nitrite,DL-lysine,L-valine,L-cysteine,DL-threonine, andDL-methionine. An additional eight sources were intermediate in the amount of growth supported. Growth by theS.trifoliorumisolates on the ammonium nitrogen sources was significantly greater than on the nitrate sources. No such difference was observed for theS.sclerotiorumisolates.DL-Phenylalanine ranked much lower andL-glutamic acid and calcium nitrate much higher as nitrogen sources for theS.sclerotiorumisolates than forS.trifoliorumisolates. Significant differences between the isolates of each species were observed on a number of nitrogen sources.

ISSN:0008-4166    

DOI:10.1139/m68-174

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Bacillus cereus14B22 exhibits a biochemical regulation by biotin. In glucose–salts or citrate–salts media, limiting amounts of biotin restrict cellular synthesis and induce synthesis of high yields of extracellularL-glutamic acid. With nonlimiting levels of biotin, abundant cellular synthesis occurs without the concomitant accumulation of glutamate. The biotin status of cells was not reflected in experiments with cell-free extracts. Citrate was converted to glutamate at comparable rates by extracts of biotin-sufficient and biotin-deficient cells. The biotin requirement for growth can be replaced with Tween 80 or with a mixture of Tween 40 and oleic acid. The yields of glutamate given by cultures of these "fatty acid-grown cells" were intermediate between those obtained with biotin-deficient and biotin-sufficient cells. Biotin deficiency also altered the fatty acid composition of the cell membrane. The proportion of straight-chain to branched-chain fatty acids is significantly smaller in low-biotin cells than in high-biotin cells. These changes did not affect cellular permeability to glutamate. Variations in the morphology ofB.cereus14B22 as influenced by biotin and the fatty acid composition of the medium are described.

ISSN:0008-4166    

DOI:10.1139/m68-175

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The structure of the diatom,Thalassiosira fluviatilis, was investigated by a study with the electron microscope of thin sections of cells fixed by OsO4, KMnO4, and glutaraldehyde. The weakly siliceous cell wall is composed of a thin sheet perforated by holes about 250 Å in diameter and arranged in a roughly orthogonal manner. At the ends of the barrel-shaped cell are marginal and central pores composed of an outer cylinder (0.25 μ in diameter and 1 μ long) arranged coaxially with an inner, smaller, shorter cylinder. The thin, perforated sheet (valve) which connects these pores is reinforced from place to place by radial or transverse ribs.Mitochondria, nuclei, chloroplasts, and pyrenoids have the same general structure and appearance as those in other diatoms. Small vacuoles are numerous but it is not known whether they are filled with gas or solution. The cells often show aggregates of an amorphous material which does not stain like lipid or protein but which may be the residue of a gelatinous, reserve carbohydrate (chrysolaminarin).

ISSN:0008-4166    

DOI:10.1139/m68-176

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

A protoplasmic extract prepared by mechanical agitation of phenol-killed tubercle bacilli was subjected to differential centrifugation to separate the insoluble intact cells and cellular debris from the soluble fraction. The soluble fraction partially purified by precipitation with ammonium sulfate was used to skin-test guinea pigs sensitized by infection with eitherM.tuberculosisor mycobacteria other than tubercle bacilli. A high degree of both sensitivity and specificity of reaction was observed when relatively small doses of protein (0.001 and 0.0001 mg) were injected into sensitized animals. Chromatographic fractionation of the partially purified extract on Sephadex G-50 did not increase the sensitivity or specificity of the protoplasmic antigen.

ISSN:0008-4166    

DOI:10.1139/m68-177

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

An intracellular polysaccharide composed of glucose subunits and structurally resembling amylopectin was isolated from vegetative cells ofClostridium botulinumtype E. Chemical and microscopic methods were employed to demonstrate amylopectin accumulation. Polysaccharide granules appeared in the cytoplasm 6 hours after inoculation, accumulated rapidly during early logarithmic growth, and reached a maximum concentration just before the onset of sporulation. With the exception of two non-toxic strains ofC.botulinumtype E, all strains examined demonstrated the ability to store a similar polysaccharide. The possibility that amylopectin may function as an endogenous source of carbon and energy is discussed.

ISSN:0008-4166    

DOI:10.1139/m68-178

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Alternaria solaniproduced two homogeneous exocellular polysaccharide fractions when grown in shake culture with fructose as the carbon source and the NH4NO3concentration of the medium 1.7 g/l. Chromatographic techniques indicated that fraction I contained glucose, galactose, and glucosamine in a 2.4:1:1 ratio whereas fraction II contained glucose, galactose, and mannose in a 6.4:1:1.2 ratio. Fraction I was found at levels seven times greater than II. Total polysaccharide produced was 1.8% of the dry weight of the mycelium and 1.2% of the available carbohydrate.Growth and polysaccharide production were greatest with fructose as the carbon source. Decreasing levels of growth occurred with mannitol, glucose, and sucrose, respectively. Exocellular polysaccharides were not detected with mannitol as carbon source. At 10 days, growth on fructose is maximum at NH4NO3concentrations of 1.5 to 2.5 g/l, but exocellular polysaccharide production is maximum at 0.8 g/l. When produced on a medium of 2.0 g/l NH4NO3the nitrogen content of I is double that when the medium is 0.8 g/l NH4NO3. In addition the ratio of I to II is about four times greater.

ISSN:0008-4166    

DOI:10.1139/m68-179

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

DDT was rapidly converted to DDD in submerged soil amended with alfalfa residue. The rate of conversion increased with increasing amounts of alfalfa. In nutrient media, 2 of 10 bacteria and 2 of 10 actinomycetes were completely inhibited by 10 p.p.m. DDT, whereas 4 of 10 bacteria and 6 of 10 actinomycetes were inhibited by 10 p.p.m. DDD. When added to agar in soil dilution plates, 10 p.p.m. DDT or DDD markedly decreased numbers of bacterial and actinomycete colonies. DDD had a broader antimicrobial spectrum and greater toxicity to microorganisms than DDT. However, both compounds had little effect on microorganisms in soil. Fungi were not affected by either compound in culture or in soil.

ISSN:0008-4166    

DOI:10.1139/m68-180

出版商:NRC Research Press    

年代:1968

数据来源: NRC