摘要:

The level and specific activity of nicotinamide adenosine diphosphate glycohydrolase (NADase) were followed throughout the asexual cycle inNeurospora crassa. A large quantity of NADase associated with the conidia was water soluble. NADase activity rapidly disappeared from the growth medium during conidial germination and from early logarithmic mycelial growth. As the mycelia aged, the enzyme accumulated in the growth medium and in the aging aconidial conidiophores, regardless of their inability to produce conidia. Since the enzyme was synthesized as the culture aged, it appears that the conidiophores age quickly with respect to their production of NADase. Conidia produced from conidiophores of the wild-type culture contained about the same quantity of NADase as the inoculum conidia. The accumulation of NADase in the conidia of wild-typeNeurosporais due to the normal differentiation of these conidia in the absence of a liquid environment. The enzyme becomes locked into the conidia being differentiated from conidiophores that contain large amounts of the NADase activity.

ISSN:0008-4166    

DOI:10.1139/m69-227

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Mass transfer of oxygen to the microbial cell is very important in hydrocarbon fermentations. One method of increasing mass transfer of oxygen is to increase its partial pressure. Increasing the total pressure of the air-feed will increase the partial pressure of oxygen, but little work has been done in this area. The present study concerns the effects of increased air pressure up to 100 pounds per square inch gauge (p.s.i.g.) on the growth ofCandida lipolyticaonn-hexadecane in an agitated 7-liter pressure reactor. Inhibited growth was observed with increasing pressure. Maximum cell mass yield at 100 p.s.i.g. was about one-third that at 15 p.s.i.g. Inhibition was attributed to a gaseous component fed in with the air stream.

ISSN:0008-4166    

DOI:10.1139/m69-228

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The granular strain ofTrichophyton mentagrophytes(M12-4) was grown in the presence of specific inhibitors of protein, deoxyribonucleic acid (DNA), and ribonucleic acid (RNA) synthesis. Those inhibitors which block protein and RNA synthesis inhibit mutant pleomorphic patch formation. Inhibitors of DNA synthesis had no effect on the visible expression of the mutant patches. Data presented suggest that initiation of the pleomorphic patch is not inhibited, but rather that mycelial growth is blocked.

ISSN:0008-4166    

DOI:10.1139/m69-229

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Proliferation of H37Rv cells in Youmans medium without glycerol and under specified conditions was inhibited and partially stopped by addition of glycerol, glucose, lactate, pyruvate, and malate, especially when these C-sources had been added in an appropriate concentration in the initial phase of growth (24 hours after inoculation of media). Addition of one of the above substances in equal concentration but already in the logarithmic phase of growth according to character of substances did not influence the course of proliferation, or it had only a shift-down effect.

ISSN:0008-4166    

DOI:10.1139/m69-230

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Soil fungistatic activity was determined in different soils using the sterile cellophane–agar diffusion method. Comparing 35 soil samples from eight profiles, the inhibitory effect onTrichoderma koningiwas found to increase with increasing soil pH irrespective of the depth at which the soil samples were taken.The fungistatic principle of seven soils was compared using 24 test fungi. Nearly all fungi affected by soil fungistasis were more strongly inhibited with increasing soil alkalinity.Susceptibility of some fungi to the fungistatic principle varied considerably with the age of the cultures from which the spores were collected. Inhibition of germination was significantly dependent on the length of preactivation of the agar discs over the soil. In some instances the inhibitory effect was considerably reduced if the agar discs were removed onto glass for the germination test after preactivation on cellophane over soil.

ISSN:0008-4166    

DOI:10.1139/m69-231

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Ochratoxin A has been obtained from both mycelium and culture filtrates ofPenicillium viridicatumWestling grown on a yeast extract – sucrose medium. Ergosterol was also identified as a metabolite. The greatest amount of ochratoxin A was detected 9 days after inoculation. Toxin production decreased greatly after several successive subcultures. However, it was possible to obtain a strongly toxinogenic isolate again from the parent culture. Small amounts of ochratoxin A were detected in 60% whole wheat bread slices used as a substrate forP.viridicatum.

ISSN:0008-4166    

DOI:10.1139/m69-232

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Transformation and transduction experiments inB.subtilisdemonstrate close linkage of a temperature-sensitive mutation to the streptomycin region. Three-factor crosses locate this mutation betweenstrandery. Using thetms+characteristic as the selected marker, crosses betweenstr-dandstr-rstrains yield small numbers ofstr-srecombinants. This demonstrates the non-identical nature of the twostrmutations investigated.

ISSN:0008-4166    

DOI:10.1139/m69-233

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

A second bacterial peptidase-like enzyme, arylamidase-II, has been isolated from cell free extracts ofNeisseria catarrhalis. Arylamidase-II action is limited primarily to the hydrolysis of α-glutamic acid and α-aspartic acid derivatives of β-naphthylamine and short peptides of glutamic acid. The enzyme was purified 450-fold by gel filtration, ion exchange, and calcium phosphate chromatography. Its pH optimum and molecular weight were 7.7 and 170 000, respectively. Aside from its restricted substrate specificity, arylamidase-II has been found to be closely related in its mechanism of action, molecular weight, pH optimum, and metal ion dependence to arylamidase-I, which catalyzes the hydrolysis of neutral amino acid derivatives of β-naphthylamine. Arylamidase-II exhibits aminopeptidase activity, requiring the amino acid residues in the N-terminal and penultimate position to be of theL-configuration in order for hydrolysis to occur.

ISSN:0008-4166    

DOI:10.1139/m69-234

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

A method for the plaque assay ofPoliovirus type Iusing plastic chambers on glass microscope slides with an agar overlay has been developed. This microtechnique offers a reliable system for plaque assays which is directly comparable with other systems. The maximum efficiency of adsorption was 80–85% and clear and countable plaques appeared within 30–34 hours. The advantages of this system include simplicity, economy of materials, and flexibility. Other applications of the technique include plaque inhibition, plaque size reduction, immunofluorescent plaque assays, and cytological studies.

ISSN:0008-4166    

DOI:10.1139/m69-235

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

In our study of the transferable nature of the multiple resistance ofShigella sonneistrains isolated in the period from 1963 to the end of 1967, it was found that at least 63.1% of the multiply resistant strains possessed the transmissible type of resistance. Contrary to expectation, no continuous increase in the percentage of multiply resistant strains was observed; rather the percentage of resistant strains fluctuated. The highest percentage (12%) was observed in 1961, 1962, 1963. In 1966 the percentage decreased to 1.3% and in 1967 increased again to 4.2%. Until June 1968 no single multiply resistant strain has been isolated. There was a decrease rather than an increase in the number of multiply resistant strains ofShigella sonnei. The authors explain this by the fact that in the period of observation no epidemic of shigellosis occurred.

ISSN:0008-4166    

DOI:10.1139/m69-236

出版商:NRC Research Press    

年代:1969

数据来源: NRC