摘要:

AbstractCloning and sequencing ofRCS1, aSaccharomyces cerevisiaegene whose product seems to be involved in timing the budding event of the cell cycle, is described. A haploid strain in which the 3′‐terminal region of the chromosomal copy of the gene has been disrupted produces cells that are, on average, twice the size of cells of the parental strain. The critical size for budding in the mutant is similarly increased, and the disruption mutation is dominant in a diploid heterozygous for theRCS1gene. Spores from this diploid have a reduced ability to germinate, the effect being more pronounced in the spores carrying the disrupted copy ofRCS1. However, disrupted cells recover from α‐factor treatment equally as well as wild‐ty

ISSN:0749-503X    

DOI:10.1002/yea.320070102

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractWe have studied the expression of alcohol oxidase (AO) in a peroxisome‐deficient mutant strain ofHansenula polymorpha. High levels of octameric, active AO (up to 3·0 U/mg protein) were detected in cells grown at low dilution rates in a glucose‐limited chemostat in the presence of choline as the sole nitrogen source. Monomeric or other intermediate forms of AO were not detected in the mutant strain. This indicated that assembly of the protein into active octameric molecules in the cytosol was as efficient as in wild‐type cells where this process is confined to the peroxisomal matrix. At relatively low rates of expression (less than 1 U/mg protein) AO was localized throughout the cytosol and, surprisingly, was also present inside the nucleus. However, at enhanced levels large crystalloids were formed. Generally one crystalloid was observed per cell, whereas smaller ones were occasionally found in developing buds. Also large crystalloids have been observed inside the nucleus. These crystalloids were not surrounded by a membrane. Based on the morphology of the molecules that constituted these crystalloids and the results of (immuno)cytochemical experiments we conclude that the crystalloids are composed of octameric AO molecules, arranged in a regular lattice, identical to the 3‐dimensional architecture previously described for the crystalline matrix of peroxisomes in methanol‐grown wild type cells ofH. polymorpha. Attempts to purify the crystalloids by conventional fractionation methods failed, due to their apparent fragility; however, (immuno)cytochemical experiments revealed that catalase and dihydroxyacetone synthase were also associated with these

ISSN:0749-503X    

DOI:10.1002/yea.320070103

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractPrevious attempts to isolate autonomously replicating sequences (ars) from the dimorphic yeastYarrowia lipolyticahave been unsuccessful. We isolated a Fil−mutant unable to produce hyphae and growing only in a yeast form to facilitatearsisolation. This mutant was transformed with aY. lipolyticaDNA bank and several unstable clones were obtained. Extrachromosomal plasmids were evidenced in yeast recovered inEscherichia coliand characterized by restriction mapping. They were able to retransform Fil−and Fil+yeast strains at high frequency and transformants displayed a slightly unstable phenotype. The detailed analysis of the plasmids showed that only two differentarssequences had been isolated, each of them corresponding to a unique sequence in theY. lipolyticagenome. We concluded that functionalarssequences that can be cloned on plasmids are rare in this ye

ISSN:0749-503X    

DOI:10.1002/yea.320070104

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractFive complementing recessive mutations that exhibit increased bacterial transposon Tn5precise excision in yeastSaccharomyces cerevisiaewere obtained by ethylmethanesulfonate treatment. One of these mutations (tex1) was submitted to extensive genetic analysis.tex1is a recessive temperature‐sensitive mutation resulting in a 20–100‐fold increase in Tn5excision. It also has increased frequencies of ochre mutation reversion, of forward mutation to canavanine resistance, and loss of chromosome III or its right arm. The possible mechanism oftex1effects is disc

ISSN:0749-503X    

DOI:10.1002/yea.320070105

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe insert‐containing, non‐canonicalori 6region of yeast mitochrondrial DNA ofSaccharomyces cerevisiaewas dissected into 15 different segments that were ligated to the integrative yeast vector YIp5. Six recombinant plasmids exhibited replicative ability in yeast and carried consensus sequences similar to the previously described 11 bp motifs active as autonomous replication sequences (ARS). In addition, all active constructions carry one or more of the characteristic GC‐rich domains A, B or C present in theori 6region, thus confirming and expanding the study of Blanc (Gene30(1984) 47–61) with the canonicalori 5. Also a new transcriptional origin is activated in theori 6region, apparently circumventing a disruption by insertion of a GC‐rich sequence that, in thisori, removes the mitochondrial promoter usually present next to the Celement. The ARS‐positive constructions correspond to the retained segments of spontaneous well‐characterized suppressive or neutral petite genomes that contain segments of t

ISSN:0749-503X    

DOI:10.1002/yea.320070106

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractSpecies of the generaSaccharomyces,Schizosaccharomyces,DebaryomycesandSchwanniomyceswere compared from their extent of divergence in three regions from small (18S) and large (25S) subunit ribosomal RNAs comprising a total of 900 nucleotides. With the exception of the closely relatedSaccharomyces bayanusandS. pastorianus, which appear to have identical sequences, all other species could be distinguished by nucleotide differences in a variable region of the large subunit, and genus‐specific nucleotides were discernible in all three regions. The taxonD. tamariidiffered markedly from other species and is excluded fromDebaryomyces. By contrast,Schwanniomyces occidentalisshowed few nucleotide differences withDebaryomycesspp. and its transfer toDebaryomycesis proposed.Schizosaccharomycesproved to be somewhat more divergent thanSaccharomycesandDebaryomyces, but species differences appear insufficient for dividing the genus. Some of the factors influencing estimates of phylogenetic distances from rRNA sequences are discusse

ISSN:0749-503X    

DOI:10.1002/yea.320070107

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe genusSchizosaccharomycescomprises a small, somewhat heterogeneous group of yeast species which have in common a unique mode of vegetative reproduction by cross‐wall formation without constriction as well as a certain degree of osmophilia, most strains having been isolated from habitats of high sugar concentration. This study evaluated inter‐ and intraspecific relationships utilizing nDNA/nDNA optical reassociation and by the analysis of physiological profiles of several strains of each species. Results demonstrate that the genus should be divided into three species:Schiz. japonicus,Schiz. octosporusandSchiz. po

ISSN:0749-503X    

DOI:10.1002/yea.320070108

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

ISSN:0749-503X    

DOI:10.1002/yea.320070101

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY