摘要:

AbstractThe cell division age dependency of sporulation was investigated in a diploid strain ofSaccharomyces cerevisiae(19el) which undergoes a single equational nuclear division during sporulation with consequent formation of asci containing two uninucleate diploid spores (apomictic dyads). Under modified nutritional conditions which partially restore meiosis and hence normal tetrad formation, newly formed (age 0) daughter cells were observed to be capable of formation of apomictic dyads but not of meiotic tetrads. Even under conditions in which only apomictic dyads developed, approximately 20% of the asci resulted from differentiation of newborn ‘inexperienced’ cells. Thus, the data indicated production of at least one bud to be a prerequisite for meiosis but not for apomixis; however, occurrence of at least one complete mitotic cell division cycle was evidently insufficient for the morphogenetic switch from diploid to haploid spore formation, since older cells bearing several bud scars often underwent apomictic dyad development, and some produced no spo

ISSN:0749-503X    

DOI:10.1002/yea.320030102

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractIn previous experiments of Girgsdies (1982), eight sterile (ste) mutants ofSchizosaccharomyces pombedid not sporulate when fused withh+orh−protoplasts. We succeeded in achieving sporulation with these mutants. Two hitherto unknownstegenes,ste7andste8, were foun

ISSN:0749-503X    

DOI:10.1002/yea.320030103

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractUsing a modification of the basic two‐dimensional polyacrylamide gel electrophoresis technique, we have undertaken a systematic identification of the polypeptides of the protein map ofSaccharomyces cerevisiaecorresponding to components of the carbon metabolism machinery. To the previous location of nine glycolytic enzyme polypeptides on the yeast protein map we add the location of 23 polypeptides. Ten of them were identified as corresponding to cytoplasmic enzymes of the carbon metabolism machinery and 13 were characterized as mitochondrial proteins. The criteria used to establish the identification of these polypeptides spots include migration with purified proteins, immunodetection, overproduction by plasmid–carrying strains and physiological behavi

ISSN:0749-503X    

DOI:10.1002/yea.320030104

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractWeak acids and hydrogen ions in different concentration combinations affect the intracellular pH value (pHi) ofZygosaccharomyces bailii. The lowest pHivalue measured was not at the most extreme, but at intermediate conditions of inhibition. Proton and organic‐acid ejection, on a cell volume basis, is greater in cells grown under inhibitory conditions and is stimulated by weak acids, whilst in cells not grown under inhibitory conditions acid efflux is lower and is depressed by weak acids; this may be important in the maintenance of tolerable pHivalues in the presence of weak acids. The concentration of benzoic acid measured internally is identical to the value expected from its pK, external pH and pHi. Addition of fructose to starved cells causes both a decreased pHiand a concomitant efflux of previously loaded benzoic acid, quantitatively in accord with the shift in equilibrium of the freely permeable undissociated acid. There is no evidence that weak acids are actively extruded. Protoplast volume also varies with hydrogen‐ion and weak‐acid concentration and this too may play a role in intracellular pH maint

ISSN:0749-503X    

DOI:10.1002/yea.320030105

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractTo identify the sequences involved in the regulation of the yeast acid phosphatase gene (PHO5) we constructed a series of hybrid promoters. Increasing lengths of 5′‐flanking sequences of thePHO5gene were placed in front of the TATA‐box of constitutively expressed acid phosphatase gene (PHO3).ThePHO5/PHO3promoter constructions were used to replace the entirePHO5,PHO3gene cluster on chromosome II. Depending on the length ofPHO55′‐flanking sequences present thePHO3gene driven by the hybrid promoter could now be derepressed in response to inorganic phosphate (low Pi) exactly as thePHO5wild type gene. A critical regulatory element was located between position −402 to −351 (upstream from ATG) and sequences further downstream (from −351 to −300) could increase transcriptional activation. The transcription levels ofPHO3were determined by northern blot analysis, under repressed (high Pi) and derepressed (low Pi) conditions which was paralleled by an increase in extra‐cellular acid phosphatase activity. Fully regulated promoter hybrids showed a 40‐fold induction of mRNA levels, comparable to wild typePHO5promoter. S1‐nuclease protection experiments revealed that thePHO55′‐flanking sequences, placed in front ofPHO3, did not change thePHO3tran

ISSN:0749-503X    

DOI:10.1002/yea.320030106

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractPurified recombinant hepatitis B surface antigen separated on polyacrylamide gels in the presence of sodium dodecyl sulphate has a very low staining index with Coomassie blue relative to a number of standard proteins. In contrast the protein stains better than average with silver nitrate. This property has been used to develop a semi‐quantitative method of estimation of recombinant surface antigen in extracts ofSaccharomyces cerevisiaeproducing this protein. The method can be used to follow purification protocols. It is quick, simple and since it measures the surface antigen biochemically, is independent of the aggregation state or conformation of the protein, a factor which can affect enzyme‐linked immunoassays which rely on antigen–antibody interac

ISSN:0749-503X    

DOI:10.1002/yea.320030107

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractMAK16is an essential gene on chromosome I defined by the thermosensitive lethalmak16–1mutation.MAK16is also necessary for M double‐stranded RNA replication at the permissive temperature for cell growth. As part of an effort to clone all the DNA from chromosome I, plasmids that complemented both the temperature‐sensitive growth defect, and the M1replication defects ofmak16–1strains were isolated from a plasmid YCp50:Saccharomyces cerevisiaerecombinant DNA library. The two plasmids analysed contained overlapping inserts that hybridized proportionally to strains carrying different dosages of chromosome I. Furthermore, integration of a fragment of one of these clones occurred at a site linked toade1, confirming that this clone was derived from the appropriate region of chromosome I. An open reading frame adjacent toMAK16potentially coding for a 468 amino acid protein was defined by sequence analysis. 185 amino acids of this open reading frame were replaced with a 1·2 kb fragment carrying theS. cerevisiae URA3gene by a one‐step gene disruption. The resulting strains grew at a rate indistinguishable from the wild type at 20°C, 30°C, or 37°C, but could not grow at 8°C. The deleted region is thus essential only at 8°C, and we name this geneLTE1(low tempera

ISSN:0749-503X    

DOI:10.1002/yea.320030108

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

ISSN:0749-503X    

DOI:10.1002/yea.320030109

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

ISSN:0749-503X    

DOI:10.1002/yea.320030110

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

ISSN:0749-503X    

DOI:10.1002/yea.320030101

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY