摘要:

Aminoacyl-tRNA's were prepared using the tRNA and enzyme fractions from ungerminated and germinated spores ofRhizopus stolonifer. No significant differences between ungerminated and germinated tRNA fractions were detected for 7 of the 10 amino acids analyzed by cochromatography on benzoylated-diethylaminoethyl cellulose columns. Quantitative changes in one of the two isoaccepting species of lysyl-tRNA and of valyl-tRNA were observed, whereas a qualitative alteration in isoleucyl-tRNA occurred during germination.

ISSN:0008-4166    

DOI:10.1139/m72-147

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Volatile metabolites produced by eight bacterial species greatly inhibited growth and sporulation of all fungi tested, namelyFusarium oxysporumf.conglutinans,Gelasinospora cerealis,Penicillium viridicatum,Trichoderma viride, andZygorhynchus vuilleminii. Alterations of colony morphology were induced in all test fungi, exceptG.cerealis. InP.viridicatum, colony contour and color were altered; inF.oxysporumf.conglutinans,T.viride, andZ.vuilleminii, the amount or distribution of aerial growth was altered.

ISSN:0008-4166    

DOI:10.1139/m72-148

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The DNA base compositions of seven members of the Saprolegniaceae were determined by cesium chloride (CsCl) gradient centrifugation. In general, base composition data correlated with morphological classification, but in several cases it indicated the necessity for revisions. In particular,Achlya inflata(eccentric group) was 42% guanine–cytosine (GC), whileA.racemosa,A.sparrowii, andA.colorata(racemose group) were 51–52% GC.Two isolates ofSaprolegnia diclinaand one ofS.parasiticawere 58–59% GC and all contained 10–20% of a lighter density satellite DNA.Analysis of thermal denaturation curves by a modification of De Ley's method (J. Theoret. Biol.22: 89 (1969)) showed that as little as 7.4% GC difference represents a large difference in DNA sequence homology. Therefore, base composition data by itself can provide a rigorous aid to the classification of the oomycetous fungi at the generic level.

ISSN:0008-4166    

DOI:10.1139/m72-149

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

A spontaneous mutant ofEscherichia coliK12 C600 was isolated which is mucoid as a result of overproduction of an extracellular polysaccharide. This strain also forms filaments, is sensitive to ultraviolet irradiation, and has its genetic lesion closely linked to thelacgene. Its phenotype and map position are analogous to thelonmutation (long form). The exopolysaccharide contains fucose, glucose, galactose, and may contain glucuronic acid, but the molar ratios of these sugars differ from those previously reported.

ISSN:0008-4166    

DOI:10.1139/m72-150

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Mucor mieheiwas grown in submerged culture at 30, 37, 40, 42.5, 45, and 48 °C. Maximum growth yield occurred at 48 °C.The effect of temperature on spore germination was examined. No spores germinated within 8 h at temperatures below 36.7 °C or above 53.5 °C. The optimum temperature for spore germination was 45 °C.Growth occurred at the marginal temperatures of 20 °C and 25 °C only when the spores were pre-germinated at 37 °C

ISSN:0008-4166    

DOI:10.1139/m72-151

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Extremely halophilic bacteria are able to survive in a natural environment exposed to high doses of ultraviolet irradiation. One such organism,Halobacterium cutirubrum, has been characterized to possess an extremely efficient photoreactivation from ultraviolet damage. A population irradiated to 1% survivors can photoreactivate to complete recovery of the original population in less than 1 h of illumination. Inhibition of carotenoid pigments by 10−6 Mdiphenylamine decreased photoreactivation efficiency. The carotene pigments have been implicated in an energy-transfer role to augment the photoreactivation mechanism

ISSN:0008-4166    

DOI:10.1139/m72-152

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Further evidence has been obtained which supports the view that alpha toxin fromStaphylococcus aureus"Wood 46" is a protease which requires activation by erythrocyte membrane proteases. Rabbit erythrocyte antiprotease prepared in mice inhibited degradation of rabbit ghosts by the toxin. Supernatant fluid of toxin-treated ghosts incubated with EDTA and then passed through a column of Sephadex G-75 yielded a fraction which was hemolytic and proteolytic. These activities were both neutralized by alpha antitoxin prepared in rabbits, but not by control sera.It was also observed that alpha antitoxin inhibited the proteolytic activity of rabbit ghosts not exposed to toxin, in contrast with control sera. Inhibitory ability was removed from the antitoxin by adsorption with a heavy suspension of ghosts, and this treatment destroyed the antitoxin's capacity to neutralize hemolytic activity of the alpha toxin.

ISSN:0008-4166    

DOI:10.1139/m72-153

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Intracellular K+in lysed freeze-thawed cell pastes of the extreme halophile,H.cutirubrum, diffused readily against a concentration gradient during equilibrium dialysis, whereas the intracellular Mg2+was not readily diffusible. The K+activity in the lysed cell pastes, determined directly by K+ion-specific electrode, was comparable to the total K-content of the cells, as determined by atomic absorption. This finding and the results of the dialysis experiment suggest that the intracellular K+inH.cutirubrumis not bound.

ISSN:0008-4166    

DOI:10.1139/m72-154

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Methods have been developed for the rapid, reproducible induction of high-density populations ofF.oxysporumchlamydospores. On transferring washed pregerminated conidia to a simple two-salts medium, chlamydospore morphogenesis was evident by 12 h and masses of mature spores could be harvested at the end of 4 days. Electron-microscope studies of thin sections of mature chlamydospores reveal a thick triple-layered cell wall. The cytoplasm contains, in addition to large lipid deposits, a nucleus, mitochondria, and endoplasmic reticulum all typical of fungal cells. Chlamydospores ofF.oxysporumexhibit two distinct types of cell surface in thin section. The outer wall layer of two of the isolates studied was smooth-surfaced while the outer layer of the two other isolates was distinctly fibrillose. Some evidence is presented suggesting that the fibrillose material arises through the partial breakdown of the original hyphal wall.

ISSN:0008-4166    

DOI:10.1139/m72-155

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Deoxyribonucleic acid preparations from two strains ofPseudomonas aeruginosanewly isolated from clinical specimens each contained double-stranded satellite DNA. The satellite DNA in one strain consisted of two components with buoyant densities of 1.705 and 1.712 g cm−3and comprised 28% of the total extracted DNA. The other strain contained 15% satellite DNA which was composed of components with buoyant densities of 1.711 and 1.718 g cm−3.

ISSN:0008-4166    

DOI:10.1139/m72-156

出版商:NRC Research Press    

年代:1972

数据来源: NRC