摘要:

Exposure of ultraviolet-irradiated, adenine-dependent haploid yeast to 2,6-diamino purine (an analogue of adenine) consistently gives rise to approximately 0.5% recessive biochemical mutants. This frequency is 22-fold higher than that obtained with either agent alone, and 150-fold higher than the spontaneous frequency. The distribution of mutants into nine discrete nutritional groups attests to the utility of the method for procuring relatively large numbers of different biochemical mutants. Several new gene markers for amino acid requirements are described, including one which controls an apparent single block for both lysine synthesis and respiratory competence.

ISSN:0008-4166    

DOI:10.1139/m63-011

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Lysineless mutants ofSaccharomyces cerevisiaewere able to grow in liquid medium supplemented withL-lysine orDL-α-aminoadipic acid but not withD-α-aminoadipic acid.Nearospora crassastrain 33933, on the other hand, grew in the presence ofD-α-aminoadipic acid as the sole nutritional supplement. Growth was less efficient withD-α-aminoadipic acid than with theDL-form or withL- orDL-lysine, but the presence of a small amount of one of these latter compounds allowed maximal utilization of theD-α-aminoadipic acid. Acid-hydrolyzed cephalosporin C, but not untreated cephalosporin C, also served as a source of the nutritional requirement.

ISSN:0008-4166    

DOI:10.1139/m63-012

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The rate of fermentation of glucose by suspensions ofCandida utilisat acid pH values is reduced by alkyl benzene sulphonate in the range 75 to 250 γ/ml. Concentrations of alkyl benzene sulphonate below 75 γ/ml decrease the rate of fermentation of glucose above pH 7 and respiration at all pH values. An upper limit of 70 to 90% inhibition of fermentation or respiration is obtained at concentrations of alkyl benzene sulphonate above 250 γ/ml, except at pH 4.2 where complete inhibition is obtained. The effect of alkyl benzene sulphonate on the fermentation of glucose by yeast protoplasts is similar to the effect observed for intact yeasts. Some enzymatic reactions of cell-free extracts are inhibited by concentrations of alkyl benzene sulphonate lower than that required to affect fermentation by intact cells. The enzyme components of the cell-free preparation appear to vary in their sensitivity to the surfactant. The results support the view that the surfactant in the micellar form disrupts the cell wall of the yeast, and unassociated molecules inactivate some enzymes vital for the metabolism of the cell.

ISSN:0008-4166    

DOI:10.1139/m63-013

出版商:NRC Research Press    

年代:1963

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m63-014

出版商:NRC Research Press    

年代:1963

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m63-015

出版商:NRC Research Press    

年代:1963

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m63-016

出版商:NRC Research Press    

年代:1963

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m63-017

出版商:NRC Research Press    

年代:1963

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m63-018

出版商:NRC Research Press    

年代:1963

数据来源: NRC

ISSN:0008-4166    

DOI:10.1139/m63-019

出版商:NRC Research Press    

年代:1963

数据来源: NRC