摘要:

AbstractAfter mother–daughter cell conjugation, formation of long holobasidia with terminal basidiospores was observed without mycelium production inRhodomyces dendrorhous(including the type strain ofPhaffia rhodozyma) on polyol‐containing media. Basidiospores are not forcibly discharged and germinate by budding. A new genusXanthophyllomyces(Filobasidiaceae, Tremellales) with a species,X. dendrorhous, is proposed for the telemorphic state ofR. dendrorh

ISSN:0749-503X    

DOI:10.1002/yea.320110202

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractPichia sorbitophilais a halotolerant yeast capable of surviving to extracellular NaCl concentrations up to 4 M in mineral medium when glucose or glycerol are the only carbon and energy sources. Evidence is presented here that glycerol, the main compatible solute this yeast accumulates so as to maintain osmotic balance, is actively co‐transported with protons. This transport system was shown to be constitutive, not needing induction by either glycerol or salt, and was not repressible by glucose. In glucose‐ or glycerol‐grown cells, a simple diffusion was detectable, and iterative calculations were performed to calculate kinetic parameters, in the presence and in the absence of NaCl. At 25°C, pH 5·0, in glucose‐grown cells these were:Km= 0·81 ± 0·11 mMandVmax= 634·2 ± 164·8 μmol h−1per g (glycerol);Km= 1·28 ± 0·60 mMandVmax= 558·6 · 100·6 μmol h−1per g (protons). Correspondent stoichiometry was approximately 1, either for these conditions or in the presence of 1M‐NaCl. An increase in acumulation capacity was evident when different concentrations of NaCl were present. This capacity was shown to be dependent on ΔpH and membrane potential, consistently with an electrogenic character. We suggest that the main role of this system is in osmoregulation, by keeping glycerol accumulated inside the cells, compensating for leakage, du

ISSN:0749-503X    

DOI:10.1002/yea.320110203

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractA consortium of European laboratories has been organized to systematically sequence the genome ofSaccharomyces cerevisiae. As part of the BIOTECH program aimed at sequencing chromosomes XI and II, we have constructed a total genomic library of yeast strain FY1679 (a direct S288C derivative) into cosmid vectors pWE15 and pOU61cos. Primary clones from four independent libraries totalling 190 genome equivalents have been stored at −80°C.A subset of 1939 independent clones (six genome equivalents) was hybridized using purified chromosomes XI and X as probes. A total of 147 chromosome XI‐specific cosmid clones was used to construct the physical map of that chromosome. Mapping methods included a combination of classical bottom‐up strategies (fingerprinting, hybridizations) and a novel top‐down strategy using I‐SceI chromosome fragmentation. The 147 cosmid clones form a unique contig covering the entire chromosome XI (666 kb) with the sole exceptions of the (C1−3A)nrepeats of the telomeres. Colinearity of cosmid inserts with yeast DNA was directly verified. A completeEcoRI map of chromosome XI was deduced from partial overlaps of cosmids and used for the sequencing program. Comparison of this map with the genetic map shows unexpected divergences that have been solved by subsequent genetic analysis, yet underline the necessity of independent physical mapping in gen

ISSN:0749-503X    

DOI:10.1002/yea.320110204

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractInSaccharomyces cerevisiae, the transcriptional regulation of most glycolytic genes has been extensively studied. By contrast, little is known about the transcriptional control of the three glucose‐phosphorylating enzymes, although this catalytic reaction has an important role in the regulation of cell metabolism. In this paper, we describe the transcriptional regulation of theHXK1, HXK2andGLK1genes in the hope of revealing differences in the steady‐state levels of mRNA associated with a particular carbon source used in the culture medium. Our results provide evidence supporting a differential expression of the three genes depending on the carbon source used for growth. We have also studied the induction and repression kinetics of mRNA expression for the HXK1, HXK2 and GLK1 ge

ISSN:0749-503X    

DOI:10.1002/yea.320110205

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractWe have developed a system for mutational analysis ofSaccharomyces cerevisiaeribosomal RNAin vivoin which yeast cells can be made completely dependent on mutant rRNA and ribosomes by a simple switch in carbon source. The system is based on a yeast strain defective in RNA polymerase I (Pol I) transcription [Nogiet al.(1991).Proc. Natl. Acad. Sci. USA88, 3962–3966]. This normally inviable strain was rescued by integration of multiple copies of the complete 37S pre‐rRNA operon under control of the inducible, Pol II‐transcribedGAL7promoter into the rDNA repeat on chromosome XII. The resulting YJV100 strain can only grow on medium containing galactose as the carbon source. A second, episomal vector was constructed in which the rDNA unit was placed under control of the constitutivePGK1promoter. YJV100 cells transformed with this vector are now also able to grow on glucose‐based medium making the cells completely dependent on plasmid‐encoded rRNA. We show that the Pol II‐transcribed pre‐rRNA is processed and assembled similarly to authentic Pol I‐synthesised pre‐rRNA, making this ‘in vivoPol II system’ suitable for the detailed analysis of rRNA mutations, even highly deleterious ones, affecting ribosome biogenesis or function. A clear demonstration of this is our finding that an insertion into variable region V8 in 17S rRNA, previously judged to be neutral with respect to processing of 17S rRNA, its assembly into 40S subunits and the polysomal distribution of these subunits [Musterset al.(1989),Mol. Cell. Biol.9, 551–559], is in

ISSN:0749-503X    

DOI:10.1002/yea.320110206

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractWe have isolatedSchizosaccharomyces pombecDNAs corresponding to the geneshis1+andhis5+. Thehis1cDNA was isolated by functional complementation of the His−phenotype in ahis1‐29 gcn3 Saccharomyces cerevisiaestrain, while thehis5cDNA was isolated as a suppressor of the 3‐amino‐1,2,4‐triazole (3‐AT) sensitivity in agcn3 S. cerevisiaestrain.his1andhis5are each present in single copy in haploidS. pombe. As is the case withS. cerevisiae, we have found that the growth of wild‐type strains ofS. pombeis sensitive to 3‐AT, an inhibitor of imidazoleglycerol‐phosphate dehydratase. This enzyme is encoded by theHIS3gene inS. cerevisiaeand thehis5+gene inS. pombe. Treatment ofS. pombecells with 3‐AT leads to a small increase in the level of thehis5transcript, but no effect is seen on the level of thehis1transcript. This is in contrast to larger increases in transcription of amino acid biosynthetic genes, regulated by the general amino acid control, seen previously in similarly treated cultures ofS. cerevisiae. These results suggest that there are likely to be some differences in the regulation of amino acid biosynthesis between these two yeasts.Sequences reported here have been deposited with GenBank as U07830 (his1

ISSN:0749-503X    

DOI:10.1002/yea.320110207

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractA prototroph revertant (Rev9) selected from an ATCase−mutant of theURA2gene containing three nonsense mutations was shown to contain two ATCase coding sequences. We cloned both ATCase coding areas to show that the duplicated locus (dl9) was the only functional one. Its size corresponded roughly to the second half of theURA2wild‐type gene. Sequence analysis of the 5′ end ofdl9indicated that this duplicated sequence was inserted within the intergenic region close to theMRS3gene and was transcribed from an unknown promoter divergently from theMRS3gene. The event leading to the revertant strain Rev9 included a rearrangement that increased the size of chromosome X by about 60 kb. In agreement with such a rearrangement, recombination was undetectable in the vicinity of the locusdl9. Genetic mapping confirms that theMRS3gene is 2 cM distal to theURA2gene on the right arm of chromos

ISSN:0749-503X    

DOI:10.1002/yea.320110208

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractExploiting the polymerase chain reaction, we have isolated a gene that encodes a putative phosphoinositide‐specific phospholipase C (PLC) of the fission yeastSchizosaccharomyces pombe. Inspection of the nucleotide sequence of the gene revealed an open reading frame that can encode a polypeptide of 899 amino acid residues with a calculated molecular mass of 102 kDa. This putative polypeptide contains both the X and Y regions that are conserved among three classes of mammalian PLC, and also contains a presumptive Ca2+‐binding site (an E‐F hand motif). The structure of the putative protein is most similar to that of the δ class of PLC isozymes. To investigate the role of this gene, designatedplc1+, gene disruption was carried out by interrupting the coding region with theura4+marker. Growth ofplc1cells was temperature‐sensitive in rich medium, and cells could not grow in synthetic medium. Expression of thePLC1gene ofSaccharomyces cerevisiaesuppressed the growth defect phenotype ofplc1−cells, a strong suggestion that theplc1+gene encodes PLC. ThePLC1sequence appears in the public data libraries, DDBJ GenBank, EMBL under the following Accession Numb

ISSN:0749-503X    

DOI:10.1002/yea.320110209

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractHere we report the physical map locations of five genes required for phospholipid biosynthesis inSaccharomyces cerevisiae. These include four structural genes (INO1, CHO2, OP13andPIS1) and one global negative regulatory gene (UME6). Collectively, this information completes the mapping of all phospholipid biosynthetic structural and regulatory genes identified to date.

ISSN:0749-503X    

DOI:10.1002/yea.320110210

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

ISSN:0749-503X    

DOI:10.1002/yea.320110211

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY