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  • Artikel  (513)
  • Gas chromatography  (280)
  • Saccharomyces cerevisiae  (233)
  • Springer  (513)
  • 1985-1989  (341)
  • 1980-1984  (172)
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of industrial microbiology and biotechnology 4 (1989), S. 49-53 
    ISSN: 1476-5535
    Schlagwort(e): l-Phenylacetyl carbinol ; Saccharomyces cerevisiae ; Yeast ; Benzaldehyde ; Biotransformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Summary The rate of production ofl-phenylacetyl carbinol bySaccharomyces cerevisiae in reaction mixtures containing benzaldehyde with sucrose or pyruvate as cosubstrate was investigated in short 1 h incubations. The effect of yeast dose rate, sucrose and benzaldehyde concentration and pH on the rate of reaction was determined. Maximum biotransformation rates were obtained with concentrations of benzaldehyde, sucrose and yeast of 6 g, 40 g and 60 g/l, respectively. Negligible biotransformation rates were observed at a concentration of 8 g/l benzaldehyde. The reaction had a pH optimum of 4.0–4.5. Rates of bioconversion of benzaldehyde and selected substituted aromatic aldehydes using both sucrose and sodium pyruvate as cosubstrate were compared. The rate of aromatic alcohol production was much higher when sucrose was used rather than pyruvate.o-Tolualdehyde and 1-chlorobenzaldehyde were poor substrates for aromatic carbinol formation although the latter produced significant aromatic alcohol in sucrose-containing media. Yields of 2.74 and 3.80 g/l phenylacetyl carbinol were produced from sucrose and pyruvate, respectively, in a 1 h reaction period.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of industrial microbiology and biotechnology 4 (1989), S. 81-84 
    ISSN: 1476-5535
    Schlagwort(e): Ethanol fermentation ; Wheat starch ; Saccharomyces cerevisiae ; immobilization ; Continuous dynamic immobilized biocatalyst bioreactor ; Biocatalyst bioreactor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Summary A simple and efficient method of conversion of wheat starch B to ethanol was investigated. Employing a two-stage enzymatic saccharification process, 95% of the wheat starch was converted to fermentable sugars in 40 h. From 140 g/l total sugars in the feed solution, 63.6 g/l ethanol was produced continuously with a residence time of 3.3 h in a continuous dynamic immobilized biocatalyst bioreactor by immobilized cells ofSaccharomyces cerevisiae. The advantages and the application of this bioreactor to continuous alcoholic fermentation of industrial substrates are presented.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 22 (1983), S. 205-212 
    ISSN: 1436-6215
    Schlagwort(e): Schwermetallwirkung ; Malatdehydrogenase ; Glutamatdehydrogenase ; Glycerinaldehyd-3-phosphatdehydrogenase ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Summary The difference between cadmium, zinc, lead, and mercury in regard of their effects on the activity of the enzymes tested is very slight. Concentrations higher than 10−5 M reduce significantly the activity of the enzymes, and concentrations of approximately 10−3 M inhibit it completely. An increase of the activity cannot be detected. The addition of combinations of cadmium, zinc, and lead results in a summing up of the toxic effects, whereas the interaction between mercury and the other three heavy metals shows a cumulative effect, which is appointed nearly completely by the heavy metal more toxic. The findings suggest that under in-vitro conditions there exists a direct interaction between the heavy metals and the enzymes.
    Notizen: Zusammenfassung Die vier Schwermetalle Cadmium, Zink, Blei und Quecksilber unterscheiden sich in ihrer Wirkung auf die Aktivität der untersuchten Enzyme nur sehr wenig. Konzentrationen über 10−5 M vermindern die Enzymaktivität signifikant, und Konzentrationen von etwa 10−3 M unterbinden sie völlig. Eine Steigerung der Enzymaktivität läßt sich nicht feststellen. Die Zugabe von Cadmium-, Zink- und Bleikombinationen führt zu einer Addition der toxischen Effekte, während bei der Interaktion zwischen Quecksilber und den anderen drei Schwermetallen die Gesamtwirkung fast ausschließlich durch das stärker hemmende Schwermetall allein bestimmt wird. Die erhaltenen Ergebnisse lassen vermuten, daß es unter Invitro-Bedingungen zu einer direkten Wechselwirkung zwischen den Schwermetallen und den Enzymen kommt.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1572-8773
    Schlagwort(e): Manganese ; Electron spin resonance ; Superoxide dismutase ; Saccharomyces cerevisiae ; Yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary Manganese accumulation was studied by room-temperature electron spin resonance (ESR) spectroscopy inSaccharomyces cerevisiae grown in the presence of increasing amounts of MnSO4. Mn2+ retention was nearly linear in intact cells for fractions related to both low-molecular-mass and macromolecular complexes (‘free’ and ‘bound’ Mn2+, respectively). A deviation from linearity was observed in cell extracts between the control value and 0.1 mM Mn2+, indicating more efficient accumulation at low Mn2+ concentrations. The difference in slopes between the two straight lines describing Mn2+ retention at concentrations lower and higher than 0.1 mM, respectively, was quite large for the free Mn2+ fraction. Furthermore it was unaffected by subsequent dialyses of the extracts, showing stable retention in the form of low-molecular-mass complexes. In contrast, the slope of the line describing retention of ‘bound’ Mn2+ at concentrations higher than 0.1 mM became less steep after subsequent dialyses of the cell extracts. This result indicates that the macromolecule-bound Mn2+ was essentially associated with particulate structures. In contrast to Cu2+, Mn2+ had no effect on the major enzyme activities involved in oxygen metabolism except for a slight increase of cyanide-resistant Mn-superoxide dismutase activity, due to dialyzable Mn2+ complexes.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 40 (1984), S. 1159-1161 
    ISSN: 1420-9071
    Schlagwort(e): Saccharomyces cerevisiae ; 5-trifluoromethyl-6-àzauracil ; yeast cell cultures ; cell division ; inhibition of
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Cell division, as studied in asynchronous cultures of yeast cells, is sensitive to 5-trifluoromethyl-6-azauracil (F3CAzU). Under defined conditions (10 mmoles l−1 F3CAzU) this compound blocks immediately and completely the process of cell division. Using synchronized cells, the time-point at which division process of yeast cell can be inhibited by F3CAzU has been determined. The inhibitor effect of this compound is completely reversed by thymine, thymidine and uracil.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 43 (1987), S. 886-888 
    ISSN: 1420-9071
    Schlagwort(e): Saccharomyces cerevisiae ; trichothecenes ; mycotoxins ; vitamins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Several trichothecene mycotoxins were shown to inhibit the growth ofSaccharomyces cerevisiae. This effect was most pronounced with the macrocyclic trichothecenes, especially verrucarin A. Much less growth inhibition was observed with T-2 toxin. Verrucarol, diacetoxyscirpenol, acetyl T-2 toxin, HT-2 toxin, T-2 tetraol and neosolaniol were inactive at a concentration of 75 μg of toxin per disc. Incubation ofS. cerevisiae with verrucarin A together with vitamins resulted in a decrease in toxicity. Pyridoxine-HCl, Ca-pantothenate, thiamine-HCl and α-tocopheryl acetate were amongst the most potent of the vitamins tested which reversed growth inhibition, overcoming the inhibitory potential of the toxins.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 43 (1987), S. 888-890 
    ISSN: 1420-9071
    Schlagwort(e): Thiaminase ; thiamine ; thiamine antagonist ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary It was found that cell-free extracts ofSaccharomyces cerevisiae contain thiaminase II which hydrolyzes thiamine and thiamine analogs. The possible involvement of this enzyme and thiamine-synthesizing enzymes in thiamine production from thiamine antagonists is discussed.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 34 (1983), S. 20-26 
    ISSN: 1570-7458
    Schlagwort(e): Dioryctria abietella ; Cone pyralid ; Lepidoptera ; Pyralidae ; Sex pheromone, (Z,E)-9,11-tetradecadienyl acetate ; Single sensillum recordings ; Electroantennography ; Gas chromatography ; Mass spectrometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé L'analyse en chromatographie gazeuse associée à une détection électroantennographique a montré que l'acétate (Z,E)-9,11-tétradécadiényle (Z,E)-9,11–14:Ac est l'un des composants de la phéromone de Dioryctria abietella Schiff (Lepid.: Pyralidae). Couplage chromatographie en phase gazeuse spectrometrie de masse a montré la présence d'acétate tétradécadiényle avec un spectre de masse et un indice de rétention identiques au Z,E-9,11–14:Ac Un récepteur cellulaire sensible à la fois au Z,E-9,11–14:Ac et à un extrait de la femelle a été identifié sous l'antenne du mâle. Les analyses des antennogrammes et de la cellule isolée ont étayé la caractérisation du composant de la phéromone comme étant Z,E-9,11–14:Ac. Un récepteur cellulaire additionnel sensible à l'acétate (Z.)-9-tétradécadiényle et à l'acétate (Z.E.)-9,12-tétradécadiényle a été trouvé sur l'antenne du mâle, mais il n'était pas activé par l'extrait de la femelle. Sur le terrain Z,E-9,11–14:Ac, présenté seul, attirait des nombres importants de mâles de D. abietella. L'addition de l'acétate (Z)-9-tétradécényle a inhibé l'attraction des mâles par les pièges.
    Notizen: Summary Gas chromatographic analyses coupled with electro-antennographic detection indicated that (Z,E)-9,11-tetradecadienyl acetate (Z,E-9, 11–14:Ac) is a pheromone component of the cone pyralid Dioryctria abietella. Gas chromatographic-mass spectrometric analyses confirmed the presence of a tetradecadienyl acetate with mass spectrum and retention index identical to Z,E-9,11–14:Ac. A receptor cell sensitive to both Z,E-9,11–14:Ac and the female extract was identified on the male antenna. An additional receptor cell sensitive to (Z)-9-tetradecenyl acetate and (Z,E)-9,12-tetradecadienyl acetate was found on the male antenna but was not activated by the female extract. In the field Z,E-9,11–14:Ac presented alone attracted significant numbers of male D. abietella. Addition of (Z)-9-tetradecenyl acetate inhibited the attraction of males to traps.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 12 (1987), S. 577-582 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Cell cycle ; Cyclic AMP ; G0 protein
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary When the cyr1-1 cells of Saccharomyces cerevisiae, which require cyclic AMP (cAMP) for growth, were starved for cAMP, cell division was arrested at the G1 state of the mitotic cell cycle and the cells entered the resting state (G0) also observed in wild-type cells transferred to sulfur-free medium. The level of cAMP in wild-type cells decreased rapidly when the cells were starved for sulfur and subsequently increased following its addition. The cyr1-1 cells starved for cAMP preferentially synthesized nine G0 proteins. The synthesis of these G0 proteins in the sulfur-starved cells was repressed by the addition of cAMP. The RAS2 val19 or bcy1 cells, which produced an elevated level of cAMP or cAMP-independent protein kinase, did not synthesize the G0 proteins under the sulfur-starved condition. The results suggest that cAMP plays a role in the transition between the proliferating state and G0 state.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 14 (1988), S. 191-199 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Site specific recombination ; 2 μ DNA plasmid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The purpose of this work is to identify and quantitate in vivo 2 μ plasmid FLP-independent recombination in yeast, using a nonselective assay system for rapid detection of phenotypic expression of the recombination events. A tester plasmid was constructed such that in vivo recombination between 2 μ direct repeat sequences produces the resolution of the plasmid into two circular DNA molecules. This recombinational event is detected as a phenotypic shift from red to white colonies, due to the mitotic loss of the plasmid portion containing the yeast ADE8 gene in a recipient ade1 ade2 ade8 genetic background. In the absence of the 2 μ FLP recombinase and/or its target DNA sequence, recombination is not abolished but rather continues at a high frequency of about 17%. This suggests that the FLP-independent events are mediated by the chromosomally-encoded general homologous recombination system. We therefore conclude that the totality of 2 μ DNA recombination events occurring in FLP+ cells is the contribution of both FLP-mediated and FLP-independent events.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 14 (1988), S. 381-385 
    ISSN: 1432-0983
    Schlagwort(e): Schizosaccharomyces pombe ; Saccharomyces cerevisiae ; Argininosuccinate lyase ; Gene cloning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A gene bank of Sau3A partially restricted Schizosaccharomyces pombe DNA in YEp13 was used to transform an arg4 mutant of Saccharomyces cerevisiae. One colony was recovered which contained the YEp13 plasmid bearing a large insert complementing the argininosuccinate lyase (ASL) mutation. As shown by restriction mapping and subcloning experiments, the DNA sequence required for complementation is localized on a 2 kb BamHI-BamHI fragment. The plasmid complemented several S. cerevisiae arg4 mutants of independent origin and a S. pombe arg7 mutant lacking ASL. Low but significant ASL activities were detected in crude extracts of these transformants. No complementation of the E. coli argH mutant was observed. Southern blot hybridizations showed that the insert originates from the S. pombe genome. No cross-hybridization was found between this sequence and S. cerevisiae DNA. It can be concluded that the cloned DNA fragment bears the S. pombe ARG7 gene coding for ASL.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 14 (1988), S. 413-418 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Chromosome length polymorphisms ; FIGE ; OFAGE
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Although Saccharomyces cerevisiae strains generally have similar chromosomal band patterns as revealed by pulsed field gel electrophoresis, individual bands often move slightly differently from one strain to the other. Surveying strains from our stock collection, we found that nearly all the bands of a certain pair of strains differed in their mobility. Some of these chromosome length polymorphisms segregated in a 2:2 ratio, indicating that they resulted from single structural alterations (i.e. additions or deletions). One of these was mapped on the right arm of chromosome 1. Others did not segrate in a simple 2:2 ratio. That is, there were progenies which had bands not present in either parent. We suggest that these new bands are the products of recombination between homologous chromosomes having two or more structural alterations.
    Materialart: Digitale Medien
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  • 13
    ISSN: 1432-0983
    Schlagwort(e): ARS ; Saccharomyces cerevisiae ; Schizosaccharomyces pombe ; Tetrahymena thermophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have isolated several Tetrahymena thermophila chromosomal DNA fragments which function as autonomously replicating sequences (ARS) in the heterologous Saccharomyces cerevisiae and Schizosaccharomyces pombe selection systems. The Tetrahymena ARS sequences were first isolated in S. cerevisiae and were derived from non-ribosomal micro- and macronuclear DNA. Sequence analysis of the ARS elements identified either perfect or close matches with the 11 by S. cerevisiae ARS core consensus sequence. Subcloning studies of two Tetrahymena ARS elements defined functional regions ranging in size from 50 to 300 bp. Testing of the ARS elements in S. pombe revealed that most of the T. thermophila inserts confer ARS function in both yeasts, at least in the sense of promoting a high transformation frequency to plasmids which contain them. However, the actual sequences responsible for ARS activity were not always identical in the two yeasts.
    Materialart: Digitale Medien
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  • 14
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Ribosomal protein genes ; CYH2
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A diploid strain of the yeast Saccharomyces cerevisiae has been constructed that has one copy of the ribosomal protein gene CYH2 completely deleted and replaced with the TRP1 gene using the method of Rothstein (1983). There are only small differences in growth rate and no detectable difference in steady state level of CYH2 mRNA between the diploid that is heterozygous for the CYH2 deletion and the parent diploid with two normal copies of this gene. This suggests that the diploid must partially compensate for the loss of one CYH2 gene. Tetrad dissection shows that haploid spores lacking the CYH2 gene cannot germinate. The lethality of this deletion can be rescued by a CYH2 cDNA on a low copy vector. Haploids which lack the genomic copy of the CYH2 gene, but contain a plasmid copy of the CYH2 cDNA are able to grow normally. These CYH2 deleted yeast haploids should be useful to analyze mutationally altered CYH2 genes and genes homologous to CYH2 from other organisms without interference from a genomic copy.
    Materialart: Digitale Medien
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  • 15
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Gene regulation ; Saccharomyces cerevisiae ; PDCI promoter
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A 870 by promoter fragment of the PDC1 gene that includes the carbon source dependent regulatory regions was investigated using 5′ and 3′ promoter deletions. The results indicate that glucose and ethanol regulation of PDC1 transcription are independently controlled by distinct cis-acting regions. The consensus sequence AAATCGATA may play a role in this regulation, while the sequence (ATCA)AACCT may be important in transcription initiation.
    Materialart: Digitale Medien
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  • 16
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Vector ; Glyphosate resistance ; Transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The E. coli aroA gene was inserted between yeast promoter and terminator sequences in different shuttle expression plasmids and found to confer enhanced EPSP synthase activity as well as resistance to glyphosate toxicity. Subsequently, a transformation system using these newly constructed vectors in yeast was characterized. The efficiency of the glyphosate resistance marker for transformation and selection with plasmid pHR6/20-1 in S. cerevisiae laboratory strain SHY2 was found to be relatively high when compared with selection for LEU2 prototrophy. The fate of the recombinant plasmid pHR6/20-1 in the transformants, the preservation of the aroA E. coli DNA fragment in yeast, mitotic stability, EPSP synthase activity, and growth on glyphosate-containing medium have been investigated. As this plasmid also allows direct selection for glyphosate resistant transformants on rich media, the glyphosate resistance marker was used for transforming both S. cerevisiae laboratory strain SHY2 and brewer's yeast strains S. cerevisiae var. “uvarum” BHS5 and BHS2. In all cases, the vector pHR6/20-1 was maintained as an autonomously replicating plasmid. The resistance marker is, therefore, suitable for transforming genetically unlabeled S. cerevisiae laboratory, wild, and industrial yeast strains.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 16 (1989), S. 247-252 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Chromosome V ; Ty elements ; tRNA genes ; Transposition hot-spots ; Yeast polymorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Ty4 is a novel transposable element in the yeast, Saccharomyces cerevisiae, which is present in only a few copies in the genome (Stucka et al. 1989). In strain C836 one of the three copies (Ty4-90) is contained in cosmid clone c90, where it resides on chromosome V. Analysis of this region reveals a “hot-spot” of transposition: in addition to Ty4-90, the locus contains a complete Ty3 element and seven singular delta, sigma and tau elements. Three tRNA genes (for His, Lys, and Ile) are located in this region, and these are closely associated with one or the other of the elements, a phenomenon commonly observed in yeast. A comparison of c90 with corresponding regions from other strains shows that the locus is highly polymorphic and that this polymorphism is explicitly associated with Ty transposition and recombination events.
    Materialart: Digitale Medien
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  • 18
    ISSN: 1432-0983
    Schlagwort(e): Gene cloning ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have carried out experiments aimed at explaining the observed variations in transformation frequencies when Saccharomyces cerevisiae or Saccharomyces carlbergensis are transformed with chimeric plasmids that contain one of 4 possible EcoRI fragments of the yeast 2-μm circle. These plasmids fall into 2 classes when used to transform 2 different yeast his3 auxotrophs, one (strain LL20) harbours indigenous 2-μm circle, and the other (strain YF233) is devoid of this plasmid. Hybrid plasmids containing either the 2.4 mega-dalton (mD) R-form EcoRI fragment (pYF88) or the l.4 mD L-form EcoRI fragment (pYF177) of 2-μm circle transform either of the two hosts at a high frequency (50,000 colonies per Mg in LL20 and 10,000 colonies per μg in YF233). Hybrid plasmids containing the 1.5 mD R-form EcoRI fragment (pYF87) or the 2.5 mD L-form EcoRI fragment (pYF178) of the 2-μm circle transform LL20 at a reduced frequency (6,000–16,000 colonies per μg) and YF233 at extremely low frequencies (1–5 colonies per μg). All plasmids retrieved from strain YF233 that had been transformed with pYF88 or pYF177 were identical to the original transforming plasmid. Of the plasmids retrieved from strain LL20 that had been transformed with pYF87 and pYF178, approximately half had acquired an extra copy of the 2-μm circle. Of the plasmids retrieved from strain LL20 that had been transformed with pYF88 and pYF177, an average of only approximately 13% had acquired an extra copy of 2-μm circle. Taken together, these observations indicate that the transformation of yeast by a plasmid lacking the ability to replicate (pYF87 and pYF1780) occurs by the recombinational acquisition of 1 copy of the host 2-μm circle, which serves to supply the incoming plasmid with missing essential sequences. A comparison of 2-μm circle DNA fragments carried by pYF88 and pYF177 indicates that the region of 2-μm circle required for high frequency transformation is a 1.2 mD segment that is common to the 2.4 mD R-form and 1.4 ml) L-form EcoRI fragments. This region extends from the EcoRI cut site adjacent to the PstI site, through to the end of the inverted repeat. However, the inverted repeat sequence alone is not sufficient to bestow high frequency transformation of yeast.
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 10 (1986), S. 943-945 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; α-factor ; Protoplasts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary When Mat a cells are treated with α-factor prior to being protoplasted and fused, the frequency of karyogamy is higher than in unarrested controls.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 10 (1985), S. 179-185 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Resistance ; Mercury ; Tyrosine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary From a cross of two strains ofSaccharomyces cerevisiae, both of which had the same (wild type or normal) level of resistance to inorganic mercury, segregants having three distinguishable resistance levels, normal, sensitive and semi-sensitive, were obtained. Genetic analyses of the parents and the progeny indicated that the levels of inorganic mercury sensitivity were determined by three distinct loci,HGS1, HGS2 andMSM1. The recessive allele of theHGS1 locus,hgsl-1, and the codominant allele of theHGS2 locus,HGS2-1, were necessary for the sensitive phenotypes, and alleles in theMSM1 locus,MSMI-1 andmsml-2, were responsible for the different sensitivity levels. In short, the strains of genotypeshgs1-1 HGS2-1 msml-2 andhgsl-1 HGS2-1 MSMI-1 were sensitive and semi-sensitive, respectively, while the strains of all other genotypes were normal. Although thehgs1-1 allele was identified as thearo7-1 mutation which confers deficiency of tyrosine and phenylalanine, mutations such asaro1B (deficiency of tyrosine, phenylalanine and tryptophan) andtyr1 (deficiency of tyrosine) had similar effects asaro7-1 on inorganic mercury sensitivity. From these results we conclude that theHGS2-1 allele causes inorganic mercury sensitivity when the cells are defective in the tyrosine biosynthesis. In fact, addition of tyrosine to the growth medium containing inorganic mercury resulted in increase of colony forming ability of the sensitive strains.
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 10 (1986), S. 665-670 
    ISSN: 1432-0983
    Schlagwort(e): Multiple drug resistance ; Genetic mapping ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In the yeast Saccharomyces cerevisiae, two nuclear pleiotropic drug resistance mutations pdr3-1 (former designation muc PR) and pdr3-2 (former designation DRI9/T7) have been selected as resistant to mucidin and as resistant to chloramphenicol plus cycloheximide, respectively. The pdr3 mutations were found not to affect the plasma membrane ATPase activity measured in a crude membrane fraction. Meiotic mapping using strains with standard genetic markers revealed that mutation pdr3-1 is centromere linked on the left arm of chromosome II at a distance of 5.9 ± 3.3 cM from its centromere and 11.6 ± 3.1 cM from the marker pet9. The centromere linked pdr3-2 mutation exhibited also genetic linkage to pet9 with a map distance of 9.8 ± 3.2 cM. These results indicate that pdr3-1 and pdr3-2 are alleles of the same pleiotropic drug resistance locus PDR3 which is involved in the control of the plasma membrane permeability in yeast.
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 10 (1986), S. 657-664 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Amino acid biosynthesis ; General control ; GCD-genes ; GCN-genes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Mutant strains, resistant against the amino acid analogues 5-methyltryptophan, 5-fluorotryptophan and canavanine were isolated, starting with a trp2 leaky auxotrophic strain. Of 10 such strains, only four turned out to be of the “general control derepressed” (gcd) mutant type. Three other isolates were shown to be defective in the general amino acid permease system, while the remaining three strains displayed low spore viability and were not further investigated. Complementation tests amongst the four new gcd-mutant strains, including strain RH558 gcd2-1 isolated earlier, yielded five complementation groups: GCD2, GCD3, GCD4, GCD5, and GCD6. All mutant strains showed a dual phenotype, which was not separable by wild type backcrosses: “constitutive derepression” and “slow growth”. Epistatis of all gcd mutations over gcn1-1, gcn2-1 and gcn3-1 was found with respect to both phenotypes, except for gcd5-1, which was lethal in these combinations. On the other hand gcn4-101 was found to be epistatic over all gcd mutations, but only with respect to the “constitutive derepression” phenotype, and not to “slow growth”; again the combination with gcd5-1 was lethal. Mutation gcd2-1 was mapped on chromosome VII, 50 cM from leu1 and 22 cM from ade6. A new model is discussed, in which GCD-genes are involved in the amino acid uptake into the vacuoles.
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  • 23
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Inducible repair ; Plasmid transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Many reports show that resistance of Saccharomyces cerevisiae to a large UV dose can be enhanced by pre-induction with a smaller one given some hours before. This work tests if such increased cell survival is associated with increased DNA repair on UV damaged plasmid transformed into yeast. There was no change in transformation efficiency of UV-damaged plasmid DNA under conditions where RAD cell survival increased 5-fold, and where rad1-1 and rad6-1 survival increased 2-fold. It is concluded that DNA repair activity involving the RAD6 and RAD3 pathways is either not inducible or is unable to work on plasmid DNA. It is suggested that the enhancement of cellular survival detected may be based on changes in cell-cycle behaviour which permit cells generally proficient in repair a greater chance to recover.
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  • 24
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; 2 μ plasmids ; Plasmid free segregants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The maximum specific growth rates (μmax) of 2 μ-plasmid-free ([cir°]) segregants of three haploid and one diploid strain of Saccharomyces cerevisiae have been determined and compared with the μmax of their 2 μ-plasmid-containing ([cir +]) progenitors. Two classes of [cir°] strains have been examined: those induced by transformation with a 2 μ-based recombinant plasmid according to the method of Dobson et al. (1980) and those isolated as spontaneous [cir°] segregants from glucose-limited continuous cultures. The μmax of the spontaneous [cir°] segregants was not found to differ significantly from that of their [cir +] parents. In all cases, however, the induced [cir°] strains had a μmax which was significantly less than that of their [cir +] counterparts. This effect was particularly marked in the case of the diploid strain where a 34% reduction in μmax was observed. The implications of these results are discussed in terms of the effect of the transformation process on host yeast cells.
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  • 25
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Minor tRNAs ; Codon usage ; Transposable elements ; Delta ; Tau
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary During characterization of the whole tRNA(Glu) family from the yeast, Saccharomyces cerevisiae, we isolated one cosmid clone bearing a tRNA(Glu) gene copy that is deviant from the major tRNA(Glu3) gene members in only five positions. This divergent tRNA(Glu) is a minor species and is represented by a single gene copy. One of the nucleotide exchanges concerns the anticodon which is modified from T-T-C in the tRNA(Glu3) gene to C-T-C which implies that this tRNA serves the codon triplet G-A-G. Two other minor yeast tRNA species have been reported which appear to be particularly designed for the translation of those codons that have a G in its third (Wobble) position. The low abundance of such minor tRNA species correlates positively to the low occurrence of most of the N-N-G codons in yeast. Furthermore, the GAGtRNA(Glu) locus represents another case of the general phenomenon in which the majority of the tRNA genes in yeast are associated with one or several transposable elements forming complex patterns. In this particular case, divergent segments of delta and tau are present in the 5′ flanking region of the tRNA gene and arranged in a novel configuration. The sequence data lend support to the view that tau is not an evolutionary young element as was earlier anticipated.
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 16 (1989), S. 315-321 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Antisuppressor ; ADE3 ; Translation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Mutations in a known yeast gene, ADE3, were shown to act as an antisuppressor, reducing the efficiency of the omnipotent suppressor, sup45-2. The ADE3 locus encodes the trifunctional enzyme C1-tetrahydrofolate synthase, which is required for the biosynthesis of purines, thymidylate, methionine, histidine, pantothenic acid and formylmethionyl-tRNAfmet. The role of this enzyme in translational fidelity had not previously been suspected.
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  • 27
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Saccharomyces cerevisiae ; Nonsense suppression ; Omnipotent suppressors ; Gene mapping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Ten dominant omnipotent suppressors of Saccharomyces cerevisiae, which were previously shown to be different from SUP46, have been examined. Nine are mapped in a region between lys5 and cyh2 on the left arm of chromosome VII. These suppressors, like SUP46, manifest sensitivity to increased temperature and the antibiotics paromomycin and hygromycin B. In addition, they have an identical action spectrum. These results strongly suggest that they are allelic to each other and they are designated SUP138. The tenth is mapped to a position between his1 and arg6 on the right arm of chromosome V. This suppressor, named SUP139, does not manifest temperature sensitivity nor antibiotic sensitivity. SUP139 and SUP138, which are clearly distinguished by means of action spectrum, act on much fewer nonsense mutations than SUP46. It is now clear that dominant omnipotent suppressors arising at a single locus are homogeneous and that their efficiency is locus-dependent. The order of efficiency is SUP46〉SUP138〉SUP139.
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 13 (1988), S. 21-23 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Transformation ; Plasmid ; Colony ; Polyethylene glycol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A rapid and simple yeast transformation procedure has been developed using colonies on agar plates. Saccharomyces cerevisiae SHY3 cells were picked up from colonies on YPD plates grown freshly or stored at 4 °C and incubated with M13RK9-T DNA at 30 °C for 1–2 h in a solution of Li+, Ca2+, Mg2+, triacetin and polyethylene glycol. About 3,500 transformants were obtained per µg of double stranded M13RK9-T DNA. Unlike the existing spheroplast techniques, single stranded M13RK9-T DNA transformed intact cells below one-hundredth frequency of the duplex form.
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  • 29
    ISSN: 1432-0983
    Schlagwort(e): Aspergillus terreus clonotheque ; Saccharomyces cerevisiae ; Homologous integration ; 2 μ circledirected chromosome destabilization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A genome clonotheque consisting of 25- to 40-kb Sau3A1 fragments of Aspergillus terreus DNA was constructed in the episomal cosmid vector pES33 containing the yeastARG4 gene. From the 475 transformants of cir° yeast strain ESH-0, 23 stable Arg + transformants were independently selected. Genetic and Southern analysis of these stable transformants showed that 39% arose as a result of recombination between cloned A. terreus DNA sequences and yeast chromosome XII. The recombination events most likely occurred in the regions of homology within the rDNA clusters of A. terreus and Saccharomyces cerevisiae.
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  • 30
    ISSN: 1432-0983
    Schlagwort(e): Yeast ; Repair ; Complementation ; Saccharomyces cerevisiae ; Schizosaccharomyces pombe ; Gene cloning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Two Saccharomyces cerevisiae genes necessary for excision repair of UV damage in DNA, RAD1 and RAD2, were introduced individually, on a yeast shuttle vector, into seven Schizosaccharomyces pombe mutants — rads1, 2, 5, 13, 15,16 and 17. The presence of the cloned RAD1 gene did not affect survival of any of the S. pombe mutants. The RAD2 gene increased survival of S. pombe rad13 to near the wild-type level after UV irradiation and had no effect on any of the other mutants tested. S. pombe rad13 mutants are somewhat defective in removal of pyrimidine dimers so complementation by the S. cerevisiae RAD2 gene suggests that the genes may code for equivalent proteins in the two yeasts.
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  • 31
    ISSN: 1432-0983
    Schlagwort(e): DNA transformation ; Saccharomyces cerevisiae ; Site-specific recombination ; 2μ DNA plasmid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The 2μ DNA plasmid of the yeast Saccharomyces cerevisiae does not confer any known selectable phenotype to the host cell carrying it. Selection of cells transformed with purified 2μ DNA therefore cannot be achieved, and the intracellular presence of 2μ can only be assessed by molecular analysis of the DNA complement. In addition, 2μ alone does not replicate in bacterial hosts, thus rendering its amplification by conventional methods impossible. We have isolated a shuttle plasmid, pBH-2L, generated by in vivo sites-pecific recombination between the endogenous 2μ DNA plasmid and pRL, a pBR322 derivative containing the yeast LEU2 gene and one 2μ repeat sequence associated with the origin of replication. This new shuttle plasmid has the property, when transformed into yeast, of undergoing site-specific recombinational resolution between its two direct repeat sequences. This releases 2μ plasmid and pRL as individual molecules. The latter can undergo progressive mitotic loss during growth in nonselective medium, ultimately leaving leucine auxotrophic transformants that contain only 2μ DNA plasmid. This system can be utilized to introduce 2μ DNA alone into cells lacking it, thereby providing a novel means to study the biology and the molecular genetics of the plasmid and its potential practical applications as a vector.
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 15 (1989), S. 113-120 
    ISSN: 1432-0983
    Schlagwort(e): Calmodulin mutant ; Nuclear division ; Chromosome stability ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The coding region of a yeast calmodulin gene was fused to a galactose-inducible GAL1 promoter, and a conditional-lethal mutant of Saccharomyces cerevisiae, in which the expression of calmodulin was regulated by galactose, was constructed. The mutant grew normally in galactose medium, but in glucose medium, in which the promoter was repressed, it ceased growing after 12–15 h. The growth arrest was associated with a decrease in intracellular calmodulin levels: after 12h, no intracellular calmodulin protein was detectable. Analysis of the terminal phenotype showed that when the cell stopped growing, it had a bud, a nucleus after S-phase and a short mitotic spindle. Thus, the defect was mainly in nuclear division. Bud growth was partially inhibited in these cells: 27% of the cells stopped growing with a small bud. Furthermore, calmodulin-deficient cells showed elevated rates of chromosome loss, possibly as the result of a defect in the precise segregation of chromosomes.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 15 (1989), S. 235-237 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Mitochondrial DNA ; Method of extraction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A rapid method for the extraction of yeast mitochondrial DNA (mtDNA) is described. In comparison with previous methods, it simplifies several steps, does not require either the isolation of mitochondria or phenol treatment and is less time consuming. This protocol gives a high yield of pure mtDNA (50–120 μg from a 100-ml culture), which can be directly used in various molecular applications: restriction enzyme digestion, electrophoresis, blotting, labeling, cloning and sequencing.
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  • 34
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Mutagen hyperresistance ; Southern, Northern analysis ; Gene transplacement ; Transposon mapping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The genes SNQ and SFA confer hyperresistance to 4-NQO and FA when present on a multi-copy plasmid in yeast. Both are non-essential genes since transplacement of SNQ by a disrupted snq-0::LEU2 yielded stable and viable haploid integrants. Southern analysis revealed that SNQ and SFA are single-loci genes, and OFAGE analysis showed that they are located on chromosome XIII and IV, respectively. Northern blot analysis of SNQ and SFA revealed poly(A)+ RNA transcripts of 2 kb and 1.7 kb, respectively. Nuclease S 1 mapping showed SNQ to have a coding region of 1.6 kb and SFA, one of 1.3 kb. The 5′ coding regions were determined for both genes, while the 3′ end could only be determined for gene SNQ. Both genes do not appear to contain introns. The SFA locus was also mapped by transposon mutagenesis. Tn10-LUK integrants disrupted the SFA gene function at sites that were determined by subcloning to lie within the SFA transcription unit.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 16 (1989), S. 139-143 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; SKI3 ; SKI5 ; M1 dsRNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have identified a mutant strain of the yeast Saccharomyces cerevisiae which overproduces killer toxin. This strain contains a single mutation which fails to complement defects in both the SKI3 and SKI5 genes, while a cloned copy of this gene complements both the ski3 and ski5 defects. The level of secreted toxin from a cDNA based plasmid is not increased in a ski3 strain, showing that the overproduction phenotype is dependent upon an increased level of M1 dsRNA.
    Materialart: Digitale Medien
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  • 36
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Psoralen photoaddition ; Interstrand cross-link ; Repair deficiency ; Genotoxicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Two different UVA irradiation systems were initially biologically calibrated with two haploid yeast strains proficient and deficient, respectively, in nucleotide excision repair. The number of DNA lesions introduced into the cell's genome by the photoactivated bifunctional furocoumarin 8-MOP was then calculated by means of the applied UVA exposure doses. At LD37 the repair-proficient wild type had about 14 ICL and 34 furan-side monoadducts in its DNA, while doubly blocked repair mutant rad3-12 pso1-1 had 2 ICL and 3 monoadducts. Locus-specific reversion of lys1-1 followed two-hit kinetics in the repair-proficient wild type and one-hit kinetics in an excision-deficient rad2-20 mutant, as would be expected if ICL was the main type of mutagenic lesion in the wild type and monoadducts the main mutagenic lesion type in the excision-deficient strain. Quantitative comparison of 8-MOP + UVA-induced ICL with those induced by bifunctional mustard revealed the former to have a much higher genotoxicity.
    Materialart: Digitale Medien
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 2 (1980), S. 115-120 
    ISSN: 1432-0983
    Schlagwort(e): Galactose fermentation ; Saccharomyces cerevisiae ; Regulatory mutant
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A novel type of regulatory mutation for galactose metabolism in Saccharomyces cerevisiae is described. The mutation named gal11 was recessive, non-allelic to GAL4, GAL80, GAL2, or GAL3, and unlinked to the gene cluster of GAL1, GAL10, and GAL7. It caused a ‘coordinate’ reduction of galactokinase, galactose-1-P uridylyl transferase, and UDP-glucose 4-epimerase by a factor of more than 5, rendering the mutant cells galactose-nonfermenting. The effect of the mutation was manifested not only in cells grown on galactose but also in cells constitutively synthesizing the galactose-metabolizing enzymes.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 2 (1980), S. 223-228 
    ISSN: 1432-0983
    Schlagwort(e): Transcriptional Units ; GAL Genes ; Saccharomyces cerevisiae ; UV mapping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The size of the transcriptional unit of the structural genes for three galactose-metabolizing enzymes which form a cluster on chromosome II in Saccharomyces cerevisiae was studied by the ultraviolet light (UV)-mapping technique. Thus the size of the primary transcripts of GAL7 for galactose-1-phosphate uridylyl transferase, GAL10 for uridine diphosphoglucose 4-epimerase, or GAL1 for galactokinase were estimated to be 0.81 x 106, 1.1 x 106, or 1.3 x 106 respectively. In the light of these data together with the known directions of transcription of the genes, we concluded that each of three genes was transcribed from its own promoter.
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  • 39
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Yeast transformation ; Centromere-containing plasmids ; Mitotic stability of minichromosomes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A mutant with unstable maintenance of hybrid plasmids containing either one of the centromeric loci CEN3, CEN6, CEN11 and arsl or the replicator of the 2 μ plasmid has been obtained. The frequency of loss of hybrid plasmids in the mutant was up to 3 · 10−1 per one generation versus 10−2 in the original strain. The unstable maintenance of minichromosomes in the mutant is controlled by a recessive nuclear gene, named SMC for stability of minichromosomes. Loss of some minichromosomes is connected with impairment of their segregation in cell division. In diploids homozygous for smc mitotic chromosomal segregation is not affected but sporulation is impaired. The question of adequacy of usage of minichromosomes for selection of mutants with impaired function of centromeric loci is discussed.
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 10 (1985), S. 171-177 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Nuclear mutations ; Mitochondrial DNA stability ; Uncoupling of phenotypes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have studied a pleiotropic mutationpetD inS. cerevisiae which both confers the inability to grow on glycerol (Gly−) and greatly increases the frequency of cytoplasmic petites (Het). The first phenotype, Gly−, is recessive, whereas the second, Het, is dominant. Genetic and biochemical analysis showed that the majority of the petites inpetD strains are not of therho° type (completely lacking mit-DNA),but of therho − type (containing partially deleted mit-DNA). This finding and the fact that the phenotype Het is dominant argue in favour of the involvement of thepetD product in the excision process of the mit-DNA. Another nuclear mutation,mod, was shown to exhibit a dominant epistasy with respect to the Het phenotype of the mutationpetD. Two types of Gly+ revertants frompetD mutants were isolated:rpa revertants, which restore completely the wild-type phenotype, andrpb revertants, which restore only the growth on glycerol, but still allow the production of high frequencies of cytoplasmic petites. Thus the mutationsmod andrpb permit the genetic uncoupling of two phenotypes induced by the mutationpetD.
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 10 (1985), S. 187-195 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Inorganic mercury ; Catabolite regulation ; Sugar uptake
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Saccharomyces cerevisiae strains sensitive to inorganic mercury (Ono and Sakamoto 1985) did not grow well on the medium rich in glucose and poor in peptone. This growth inhibition, like growth inhibition caused by inorganic mercury, was relieved by exogenous tyrosine. Sugars such as fructose and mannose were as inhibitory as glucose, but glycerol was not at all. Galactose was inhibitory but not so much as glucose. Agal2l mutation (defective in galactose uptake) partly relieved growth inhibition caused by excess galactose. Moreover, it was found that some of revertants which gained ability to grow well in the presence of excess glucose were defective in the glucose uptake. From these observations, we conclude that growth inhibition of the inorganic mercury sensitive strains by excess sugar is a consequence of the catabolite regulation. In other words, the inorganic mercury sensitive strains are hyper-sensitive to the catabolite regulation due to the presence of theHGS2-1 allele.
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 10 (1986), S. 491-494 
    ISSN: 1432-0983
    Schlagwort(e): Protoplast fusion ; Saccharomyces cerevisiae ; Schwanniomyces castellii ; Starch fermentability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Prototrophic hybrids have been obtained by the fusion of various auxotrophic haploid strains of Saccharomyces cerepisiae and Schwanniomyces castellii. The fusion hybrids showed starch fermentability which derived from one of the fusion parents, S. castellii. Surprisingly, these fusion hybrids were found to exhibit excellent sporulation and spore germination. The progenies of these fusion hybrids showed a few aberrant segregations, but mostly normal segregation for auxotrophic genetic markers. They also showed many tetrads with an apparently digenic segregation (2:2, 3:1 and 4:0) for starch fermentation. On the other hand, mating types of segregants of the fusion hybrids were determined by the prototrophic recovery method. Consequently, tetrad types for mating type were mostly 2a:1α:1 non-mater and several asci showed tetrad types of 2a:2 non-mater and 2a:2α. The 60 prototrophic fusion hybrids and its segregants did not secrete α-amylase on the starch agar plate. However, all of the data suggested that fusion hybrid could carry two dominant genes (STAB and STAC) to ferment starch, and that the two genes STAB and STA2 may be identical or allelic as may be the genes STAC and STA3.
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 11 (1986), S. 93-96 
    ISSN: 1432-0983
    Schlagwort(e): Uracil permease gene ; Saccharomyces cerevisiae ; Chromosomal mapping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The gene FUR4, coding for the uracil permease in Saccharomyces cerevisiae, was mapped on chromosome II, at a distance of 7.8 cM from the centromere on the right arm of the chromosome. In a first step, we used the chromosome loss mapping method developed by Falco and Botstein (1983) to determine on which chromosome the gene mapped. After the observation that FUR4 was closely linked to GAL10, one of the three genes forming the gal cluster (Bassel and Mortimer 1971), we could determine precisely the position of the gene on chromosome II.
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  • 44
    ISSN: 1432-0983
    Schlagwort(e): Schizosaccharomyces pombe ; Saccharomyces cerevisiae ; DNA ligase ; DNA damage
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary UV-irradiation of stationary phase cells of Saccharomyces cerevisiae and Schizosaccharomyces pombe leads to a 9-fold and 90-fold increase in transcript levels from the respective DNA ligase genes CDC9 and CDC17, whereas exponential cells show only 3-fold and 2-fold increases. Induction of CDC9 after MMS treatment and γ-irradiation was also observed by using a CDC9-lacZ translational fusion and assaying for β-galactosidase. Surprisingly, irradiation of S. cerevisiae induces only a 50% increase in DNA ligase itself, probably reflecting the extremely high in vivo stability of the enzyme. The UV-induction of ligase may be part of a “fail-safe” mechanism which, together with the enzyme stability, ensures adequate supplies of this essential enzyme.
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 11 (1986), S. 193-200 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Ty elements ; Transposable elements ; Retroviruses ; tRNA genes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have isolated and characterized a Ty element from a yeast cosmid library which exhibits several unsual features: it is flanked by non-homologous delta elements and directly associated with a singular delta element. A tRNA(Glu3) gene and tRNA(Cys) gene are found in conjunction with this element, located in opposite orientation on either end of it. The sequence information now available for several Ty elements has been used in a detailed comparative analysis to determine conserved features among the Ty elements, preferably between class I elements and a class II element. Highly conserved sequence motifs appear to be located at the borders of particular segments that correspond to the putative protein domains of the Tys. Furthermore, we include a comparison of the best-conserved amino acid homologies for these putative proteins of Ty elements, transposable elements from other organisms and several retroviral proviruses to confirm their close structural resemblance.
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  • 46
    ISSN: 1432-0983
    Schlagwort(e): Rho°-petites ; Lycorine ; Mitochondrial DNA replication ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary This paper describes the isolation and characterization of mutants affected in the maintenance of the mitochondrial (mt) genome. The rationale of the screening procedure is based on the observation that the alkaloid lycorine inhibits growth of rho −-mutants, whereas rho°-mutants, devoid of mt DNA, are resistant to this drug (Del Giudice et al. 1984). Fourteen temperature sensitive mutants have been isolated that display the following phenotype: -Growth on fermentable medium at 23°C and 35°C (exclusion of general temperature-sensitive mutants). -no growth at 23°C and growth at 35°C on fermentable medium containing lycorine (selection for mutants producing rho°-petites). -growth at 23°C and no growth an 35°C on non-fermentable medium (selection for temperature-dependent loss of respiratory competence). These mutants were termed tmm (for temperature sensitive maintenance of mt genome). Mutant tmm1-1 was analyzed genetically and biochemically. It carries a recessive nuclear mutation which gives rise to 90–95% cytoplasmic petites at the non-permissive temperature. The population of petites consists of more than 95% rho°-petites as shown by their resistance to lycorine, by staining with 4′,6-diamidino-2-phenylindole (DAPI), and by Southern hybridization with mt DNA probes. Wild-type control cultures produced approximately 1% petites with less than 10% rho°-mutants.
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 11 (1986), S. 211-215 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Hyperresistance ; DNA damaging agents ; Genotoxic effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In order to study resistance to DNA damaging agents, yeast DNA segments conferring hyperresistance in this organism to such genotoxic agents were selected for among yeast cells transformed by a yeast genome library based on the multi-copy vector plasmid YEp13. Genetic variants hyperresistant to 4-nitroquinohne-N-oxide, formaldehyde, and alkylating agents were isolated and the respective hyperresistance determinants shown to co-segregate with the vector plasmid. Phenotypical characterization indicated different degrees of resistance, few cases of cross-resistance and differing structural stability of the cloned DNA. By transfer to E. coli and subsequent retransformation of yeast a number of plasmids was shown to stably carry the genetic information for hyperresistance.
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 11 (1986), S. 217-225 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Gene cloning ; Invertase genes ; Multicopy vector
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Six unlinked loci for invertase structural genes are known in the yeast Saccharomyces cerevisiae: SUC1-SUC5 and SUC7. These genes are similar in structure and expression but not identical. Different yeast strains possess none, one or several of these genes. We have isolated the genes SUC1-SUC5, subcloned them into the multicopy vector YEp24 and compared the expression of the five SUC genes in one recipient strain. SUC2 was isolated by transformation of a suc0 strain with a gene pool and complementation to sucrose fermentation. SUC4 was cloned from a minipool of chromosomal fragments which were shown to contain SUC4 by Southern hybridization. SUC1, SUC3 and SUC5 were isolated using the method of plasmid eviction. A plasmid containing regions flanking SUC4 was integrated next to these SUC genes. The plasmid together with the SUC genes were then cut out of the chromosome using an appropriate restriction endonuclease. The length of chromosomal DNA fragments containing the different SUC genes were 4.8 kb for SUC1, 5.2 kb for SUC2, 4.8 kb for SUC3, 12.8 kb for SUC4 and 17.2 kb for SUC5. Fragments containing the complete SUC genes and the sequences controlling their expression were subcloned into YEp24 and transformed into a strain without any active invertase gene. Invertase activity of transformants was measured after growth repressing (8% glucose) and derepressing (2% raffinose) conditions. As expected from results with strains carrying the individual SUC genes in a chromosomal location, the SUC genes were expressed to a different extent.
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  • 49
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Nucleo-mitochondrial interactions ; Mitochondrial status ; Dominant lycorine resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Mutants resistant to 200 µg/ml of the alkaloid lycorine (LYC R) in non-fermentable substrate were isolated after nitrosoguanidine mutagenesis. Tetrad analysis and growth of heterozygous (LYC R/lyc s) diploids from two different mutants revealed that a single nuclear and dominant mutation is responsible for the resistant phenotype. In the wild type total protein synthesis is only slightly inhibited, whereas DNA and RNA synthesis is lowered to about 30% of the control. In the lycorine resistant mutants all macromolecular syntheses are unaffected by the drug.
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 11 (1987), S. 399-406 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Mercury resistance ; Tyrosine uptake ; Catabolite regulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In Saccharomyces cerevisiae, the HGS2-1 allele confers sensitivities to inorganis mercury (Ono and Sakamoto 1985) and to excess fermentable sugars such as glucose (Sakamoto et al. 1985); exogenous tyrosine antagonizes both inorganic mercury and excess glucose. In this sutdy, the inorganic mercury sensitive strain has been shown to have about twice more glucose-1,6-bisphosphate and slightly less pyruvate than the normal strains, suggesting that the inorganic mercury sensitive strain has the reduced aldolase activity. It has been also shown that the growth retarded cells accumulate trehalose, by which the lower level of glucos-6-phosphate in the inorganic mercury sensitive strain is accounted for, and that inorganic mercury, presumably excess glucose also, causes growth inhibition via depletion of cellular tyrosine. The mechanism how cellular tyrosine is depleted by inorganic mercury or excess glucose is accounted for by the facts that (1) the tyrosine uptake activity is decreased with increase of glucose concentration in growth medium, (2) HGS2-1 enhances the effect of glucose on the tyrosine uptake activity, and (3) inorganic mercury inhibits the tyrosine uptake system by binding to its SH-group(s). Thus, it is concluded that the role of tyrosine is not to detoxify inorganic mercury nor excess fermentable sugars but simply to counteract depletion of cellular tyrosine induced by them.
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 11 (1987), S. 445-450 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Ribosomal protein genes ; Genetic mapping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have used the 2 μ mapping method described by Falco and Botstein (1983) and tetrad analysis to map four ribosomal protein genes (two linked pairs) in S. cerevisiae. One pair (rp28–rp55 copy 1) is on chromosome XV, 14 cM proximal to ARG8. The other pair (rp55–rp28 copy 2) is 19 cM from the centromere on the left arm of chromosome XIV. To map copy 1 we used the E. coli β-galactosidase gene rather than a yeast gene to mark the ribosomal protein chromosomal locus. This provided a more sensitive color screening assay for chromosome loss in the 2 μ method. It also removed the restriction that the mapping tester strains must be mutant for the plasmid marker.
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 11 (1987), S. 483-490 
    ISSN: 1432-0983
    Schlagwort(e): Double-stranded RNA (dsRNA) ; Yarrowia lipolytica ; Saccharomyces cerevisiae ; Virus-like particles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Some strains of the yeast Yarrowia lipolytica possess virus-like particles (VLPs) which encapsidate a double-stranded RNA (dsRNA) genome designated Ly. We report here that these VLPs have two associated polypeptides of molecular weights 83 kd (VLy-P1) and 77 kd (VLy-P2). Denatured Ly-dsRNA was used to program a cell-free rabbit reticulocyte translation system, resulting in the appearance of four major products, viz. Ly-P1 (83 kd); Ly-P2 (77 kd); Ly-P3 (74 kd) and Ly-P4 (68 kd). The in vivo viral-associated protein VLy-P1 co-migrated on SDS-polyacrylamide gels with the in vitro product Ly-P1 and, similarly, VLy-P2 co-migrated with Ly-P2. Peptide mapping data confirm the identity of the in vivo products (VLy-P1 and VLy-P2) and their in vitro counterparts. The conclusion made is that VLy-P1 and VLyP2 are almost identical primary translation products of the Ly genome, derived from a single or multiple species of Ly-dsRNA. RNA blot hybridizations using L1A M1 and separately, L2A M2 probes prepared from appropriate K1 and K2 Saccharomyces cerevisiae killer strains, failed to show any detectable homology to Ly-dsRNA, substantiating the uniqueness of the Ly genome with respect to the K1 and K2 S. cerevisiae dsRNA killer systems.
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  • 53
    ISSN: 1432-0983
    Schlagwort(e): ARS ; Linear DNA killer plasmid ; Replication ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary By use of linear DNA plasmid pGKL2 from the yeast Kluyveromyces lactis we have constructed hybrid plasmids carrying a LEU2 gene of Saccharomyces cerevisiae as a selectable marker. The replication properties of hybrid plasmids in yeasts were investigated. We demonstrated that the insertion of a LEU2 gene into pGKL2 resulted in circularization of the hybrid plasmids and pGKL2 segment supported autonomous replication of the plasmids. Moreover, the hybrid plasmids propagated autonomously, independently of the presence of the natural pGKL2 plasmid.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 12 (1987), S. 511-517 
    ISSN: 1432-0983
    Schlagwort(e): Mating-type switching ; Cytoduction ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Use of a selective system for cytoduction in Saccharomyces cerevisiae allowed us to monitor hybrid formation and to clone the haploid nuclei of cells which have participated in illegitimate matings: a × a, α × α. Our approach has made it possible to select nuclei with mating-type switches and mutations within the MAT locus. It was shown that matings in α × α crosses often proceed through nonheritable genetic changes located within chromosome III. We suggest that these non-heritable genetic changes are due to premutational lesions, expressed phenotypically as transient α-matingtype. After a mating event these lesions are either repaired or converted to true mutations within the MAT locus.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 13 (1988), S. 283-289 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Inducible antisense gene ; Acetolactate synthase ; Bradytrophic phenocopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We report for the first time on the regulation of gene expression in yeast by antisense RNA. Chimaeric genes were constructed containing the 5′ upstream and partial coding sequence of SMR1 — a sulfometuron methyl resistant allele of the ILV2 locus. Such fragments were placed 5′ to 3′ and 3′ to 5′ under control of the GAL10 promoter and CYCl terminator in a high copy YEp plasmid. Following galactose induction only transformants containing antisense RNA genes showed biological activity against SMR1 gene expression. Antisense RNA inhibited synthesis of the SMR1 gene product acetolactate synthase and thus repressed cellular growth which resulted in a bradytrophic auxotroph revertable by addition of isoleucine and valine. Antisense RNA inhibition was enhanced in galactose medium containing sulfometuron methyl and in gcn4 cells deficient for positive regulation of the ILV2 locus. This system can be used to study factors that interfere with antisense RNA function and to assign biological function to randomly cloned DNA fragments.
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 14 (1988), S. 331-335 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Meiosis ; Deletion mutations ; Sequence dissimilarities
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A diploid yeast strain with extensive sequence dissimilarity in homologous regions near the LYS2 locus was sporulated, and spontaneous lys2 and lys5 mutant spores, selected on α-amino adipate, were analyzed. As many as 50% of the mutant spores contained a deletion in LYS2. These deletions occurred at a frequency of 5.0 × 10−7. While deletions of various sizes and endpoints were obtained, all the deletions recovered in this study included the border between homologous and non-homologous sequences located 4 kb upstream of LYS2. Large lys2 deletions that extended into an adjacent CYH2 duplication occurred at a frequency of 2.0 × 10−7, more than 1,000 times the frequency of the CYH2-LYS2 deletions found in a related haploid strain. This high frequency of CYH2-LYS2 deletions was observed only after sporulation of the diploid strain, and was dependent upon extensive sequence dissimilarity near the LYS2 locus.
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  • 57
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Allosuppressor ; Translation ; Fidelity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Allosuppressor (sal) mutations enhance the efficiency of the yeast ochre suppressor SUQ5 and define five unlinked loci, SALT-SALS. A number of sal4 mutants were isolated and found to have pleiotropic, allele;specific phenotypes, including hypersensitivity in vivo to paromomycin and other antibiotics that stimulate translational errors in yeast. To examine further the nature of the SAL4 gene product, the wild type SAL4 gene was isolated by complementation of a conditional lethal allele sal4-2, and demonstrated to be a single copy gene encoding a single 1.6 kb transcript. Restriction mapping and DNA hybridisation analysis were used to demonstrate that the SAL4 gene is identical to the previously identified omnipotent suppressor gene SUP45 (SUPT). Our results implicate the SAL4 gene product as playing a major role in maintaining translational accuracy in yeast.
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  • 58
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Protoplast fusion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The percentage of hybrids formed during protoplast fusion in Saccharomyces cerevisiae is determined by the percentage of protoplasts at the GI/S boundary of the cell cycle.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 59
    ISSN: 1432-0983
    Schlagwort(e): Peroxisomes ; Protein import ; Saccharomyces cerevisiae ; Hansenula polymorpha
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The DAS gene of Hansenula polymorpha was expressed in Saccharomyces cerevisiae under the control of different promoters. The heterologously synthesized dihydroxyacetone synthase (DHAS), a peroxisomal enzyme in H. polymorpha, shows enzymatic activity in baker's yeast. The enzyme was imported into the peroxisomes of S. cerevisiae not only under the appropriate physiological conditions for peroxisome proliferation (oleic acid media), but also in glucose-grown cells where it induced the enlargement of the few peroxisomes present. This growth process was not accompanied by an increase in the number of microbodies, which suggests a separate control mechanism for peroxisomal proliferation.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 15 (1989), S. 399-401 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces exiguus ; Saccharomyces cerevisiae ; HO gene ; MAT gene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The DNA of Saccharomyces exiguus was analyzed by Southern hybridization using cloned MATa, MATα, and HO genes of Saccharomyces cerevisiae as probes. It was shown that S. exiguus has a DNA sequence homologous with the HO gene of S. cerevisiae and that this DNA sequence is on a chromosome of about 940 kb of DNA in S. exiguus. However, there is no DNA sequence in S. exiguus that is homologous with the MAT genes of S. cerevisiae.
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 23 (1986), S. 113-118 
    ISSN: 1432-1432
    Schlagwort(e): Primordial terrestrial atmospheres ; CH4, C2H2, CO2 ; Prebiotic synthesis ; High-frequency discharge ; Hydrocarbons ; Gas chromatography ; Mass Spectrometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Various hydrocarbons were synthesized by high-frequency discharge in a primordial terrestrial model atmosphere. The products were extracted by benzene or methanol and analyzed by GC-MS. The mean carbon chain length of the hydrocarbons formed by the discharge through pure CH4 gas was less than 6. Benzene was also obtained. Some isomers were obtained for each of the hydrocarbons containing a given number of carbons. When a small amount of C2H2 was added to the CH4, longer chain compounds were formed, as compared with discharge in CH4 only. However, when the amount of C2H2 was increased, unextractable high molecular weight compounds were produced. The amounts of products decreased as the mixing ratio of CO2 to CH4 increased. No hydrocarbons were detected when the ratio of CO2/CH4 exceeded 1.
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Trees 1 (1987), S. 94-101 
    ISSN: 1432-2285
    Schlagwort(e): Monoterpenes ; Abies alba Mill ; Resin ; Seeds ; Gas chromatography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Using gas-chromatographic methods, the variability of the contents of monoterpene hydrocarbons (α-pinene, β-pinene, Δ3carene and limonene) in the resin of silver fir seeds (Abies alba Mill.) was studied. Resin cavities were characterized according to their position on the seed surface. It was estabilished that the terpene content of the resin of cavities localized on the abaxialadaxial surfaces of the seed differs significantly, creating a gradient of resin composition around the circumference of the seed. The differences between various resin cavities of single seeds were greater than the differences between different seeds of a single cone and between seeds of various cones on a single tree. An accurate definition of the resin cavity location on the seeds appears to be a fundamental condition for the collection of a sample representing the resin composition of individual trees. Resin biosynthesis in the course of organogenesis and the control of terpene contents in the resin of various locations on the seed and the cone are discussed.
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Applied microbiology and biotechnology 16 (1982), S. 75-80 
    ISSN: 1432-0614
    Schlagwort(e): Immobilization of yeast ; Saccharomyces cerevisiae ; Ethanol production
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Summary Baker's yeast (Saccharomyces cerevisiae) was immobilized in gels made of prepolymerized, linear, water soluble polyacrylamide, partially substituted with acylhydrazide groups. Gelation was effected by the addition of controlled amounts of dialdehydes (e.g. glyoxal). The immobilized yeasts retained full glycolytic activity. Moreover, the entrapped cells were able to grow inside the chemically corsslinked gel during continuous alcohol production. Glyoxal was found to be the most favourable crosslinking agent for this system. the system employed allowed for the free exchange of substrate and products. The gel surrounding the entrapped cells had no effect on temperature stability profile. On the other hand, substantial enhancement in survival of cells in presence of high ethanol concentrations was recorded for the entrapped yeast. The capability of the immobilized yeast to carry out continuous conversion of glucose to ethanol was demonstrated.
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  • 64
    ISSN: 1420-9071
    Schlagwort(e): Saccharomyces cerevisiae ; growth conditions ; kinaseless mutant ; plasma membrane vesicles ; glucose transport ; kinetics and computer simulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In this study experimental data on the kinetic parameters investigated by other authors1–5, 11 together with own data on plasma membrane vesicles, have been subjected to a computer simulation based on the equations describing facilitated diffusion. The simulation led to an ideal fit describing the above data. From this it can be concluded that glucose is transported by facilitated diffusion, and not by active transport as was postulated by Van Steveninck14, 15. The simulation method also demonstrates that the fast sampling technique used by these authors1–5,11 underestimates the fluxes. Thus, the parameters given do not contribute to the understanding of glucose transport under different metabolic conditions. The K value of plasma membrane vesicles prepared from glucose-repressed cells is around 7 mM. Derepression, particularly by galactose, causes a highly significant increase in affinity as shown by a decrease in the K value to 2 mM. The highest affinity was measured in a triple kinaseless mutant grown on glycerol with a K value of 1 mM. If seems, therefore, that the kinetic parameters derived from initial uptake rates of glucose in intact cells1–5,11 using single flux analysis, such as Eadie-Hofstee- or Lineweaver-Burk-plots, are in error.
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  • 65
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; DNA replication origins ; GC clusters ; Genome rearrangements
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We determined the restriction maps and primary structures of two as yet poorly characterized regions of the mitochondrial genomes of different wildtype strains of Saccharomyces cerevisiae. These regions respectively comprised the ori1 sequence and the newly identified ori8 sequence. Ori1 and ori8, together with their flanking sequences, exhibit a large polymorphism, resulting from specific variations due to insertions or deletions of optional GC clusters at different locations. The mechanisms underlying such sequence rearrangements are discussed.
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  • 66
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Cytochrome c ; Regulatory gene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The CYP1 gene has previously been identified as coding for a positive trans active factor that activates the expression of CYC1 and CYP3, which are the structural genes for isol- and iso2-cytochrome c. Two phenotypically distinct classes of CYP1 mutations can be obtained indicating that CYC1 and CYP3 are differentially regulated by the product of CYP1. The HAP1 gene codes for a product which has previously been proved to be necessary for the expression of the heme dependent CYC1-UAS1 cis regulatory sequence. In this article, we show by complementation and recombination that CYP1 and HAP1 are the same gene, moreover we identify hap1-1 as an iso2-cytochrome c underproducer mutation of the CYP1 gene.
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  • 67
    ISSN: 1432-0983
    Schlagwort(e): agα1 Mutant ; Agglutination ; Gene dose effect ; Mapping ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A recessive agα1 mutation leads to specific defect in sexual agglutinability specifically in α cells of the yeast Saccharomyces cerevisiae. The cryptopleurine resistance gene cryR 1, closely linked to the mating type locus, was used to select α/α strains which emerged from α/α strains by mitotic nonreciprocal recombination, to genetically analyse agα1, since agα1 is expressed only in α mating type. The agα1 gene was found to be linked to the centromere tightly, to met3 at 4.4 cM, and to ilv3 at 12 cM on chromosome X. Sexual agglutinability of α cells was shown to be dependent on the dose of the AGα1 gene, using α/α isogenic strains carrying AGα1/AGα1, AGα1/agα1 or agα1/agα1. The sst2-1 mutation did not suppress the agα1 mutation. Based on these results, function of the AGα1 gene is discussed.
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  • 68
    ISSN: 1432-0983
    Schlagwort(e): β-glucosidase ; Kluyveromyces fragilis ; DNA sequence ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The complete nucleotide sequence of the β-glucosidase gene of Kluyveromyces fragilis has been determined. This sequence contains an open reading frame of 2535 base pairs encoding a protein of 845 amino acids. Analysis of the transcription products revealed only one transcript of about 3 kb identical in both Kluyveromyces fragilis and in the expression host Saccharomyces cerevisiae. The protein molecular weight of 93,811 Kd deduced from the sequence is consistent with the 90,000 Kd determined by SDS polyacrylamide gel electrophoresis with the purified protein. Mapping of the starts of transcription shows that two starting points are used in the natural host Kluyveromyces fragilis. A comparison of the amino acid sequence with that of other β-glucosidases revealed three regions of homology. One of these regions contains an amino acid sequence very similar to a peptide isolated from the active site of β-glucosidase A3 from Aspergillus wentii and could be implicated in the catalytic mechanism of these glucolytic enzymes.
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 12 (1987), S. 413-420 
    ISSN: 1432-0983
    Schlagwort(e): Glucanolytic brewer's yeast ; Endo-β-1,4-glucanase ; Chromosomal integration ; Transformation ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Barley β-glucans present in wort reduce beer filtrability and cause hazes and precipitates in the finished beer. The endo-β-1,4-glucanase enzyme, EGI, found in the filamentous fungus Trichoderma reesei, is capable of efficiently hydrolyzing these β-glucans. The cDNA copy of the eg11 gene, which codes for the EGI enzyme, was coupled to yeast regulatory sequences and transferred to a brewer's yeast using the yeast copper chelatin gene CUP1 as a selection marker in the transformation. The eg11 gene was transferred to the yeast both on a multicopy plasmid and on an integrating plasmid. In both cases, highly glycosylated, active EGI enzyme was secreted into the medium. Barley β-glucans present in wort were efficiently hydrolyzed by the recombinant brewer's yeast.
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 12 (1987), S. 405-411 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Adenylate kinase ; Nucleotide sequence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The structural gene for yeast adenylate kinase (AKY) has been isolated and analyzed with respect to its nucleotide sequence. Southern and northern analyses imply that the gene is single copy and is transcribed into an mRNA of about 1,100 bases. The flanking regions of the gene contain the canonical elements typical for initiation and termination of transcription of yeast protein coding genes. The amino acid primary structure deduced from the open reading frame is identical with the protein sequence reported for yeast adenylate kinase (Tomasselli et al. 1986) with the exception of an extension of two amino acids (Met-Ser) at the N-terminus and aspartic acid instead of asparagine at the carboxyl end. Yeast adenylate kinase reveals a striking homology with both the mammalian cytosolic and, particularly, with the mitochondrial isozyme. It has an insertion of 31 amino acids in the middle segment of the protein, when compared to the cytosolic version of the mammalian enzyme. A strikingly conserved insert sequence of the same length and at exactly the same position is present in the mammalian mitochondria) isozyme. The question of the subcellular location of the yeast enzyme is discussed.
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  • 71
    ISSN: 1432-0983
    Schlagwort(e): Formaldehyde ; DNA-protein cross-links ; Repair ; Saccharomyces cerevisiae ; Hyperresistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The formation and removal of formaldehyde-mediated DNA protein cross-linking was measured by CsCI density gradient analysis in yeast strains of differing resistance to formaldehyde. Wild-type cells and transformants made hyperresistant to formaldehyde by a multi-copy vector containing the yeast SFA gene were specifically labeled in their DNA and incubated in the presence of formaldehyde. Treatment with formaldehyde lead to the formation of equal amounts of DNA protein cross-links; subsequent liquid holding of cells for 24 h resulted in the removal of nearly all DNA protein crosslinks regardless of the original formaldehyde resistance status of the strains.
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  • 72
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Multiple mutants of DNA repair ; Sensitivity to nitrogen mustard and to radiation ; Thermoconditional DNA repair
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Three haploid yeast mutants (snm) sensitive or thermoconditionally sensitive to the DNA cross-linking agent nitrogen mustard (HN2) were crossed with four rad strains representing mutations in the three pathways of DNA dark repair. The resulting haploid double and triple mutant strains were tested for their sensitivity to UV, HN2 and HN1. From the observed epistatic or synergistic interactions of the combinations of mutant alleles we could derive the relation of the SNM1 and SNM2 genes to the postulated repair pathways. Alleles snm1-1 and snml-2 ts were found epistatic to genes of the rad3 group, whereas snm2-1 ts was epistatic to rad6. The snm1 and snm2 mutant alleles interacted synergistically. From these data it is concluded that the SNM1 gene product plays a cross-link specific role in excision repair while the SNM2 gene product may be involved in a system of error-prone repair.
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 7 (1983), S. 165-166 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Cephalosporium acremonium ; Mitochondrial hybrid vector ; Nuclear association
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The hybrid vector pCP2, consisting of the bacterial plasmid pBR325, the nuclear gene Leu-2 of Saccharomyces cerevisiae and a fragment of mitochondrial DNA from Cephalosporium acremonium, was found to associate with the nucleus in a transformed strain of Saccharomyces cerevisiae. This was inducted by (1) efficient expression of the Leu-2 gene as evidenced by a short generation time on selective medium; (2) independence of Leu-2 gene expression from mitochondrial protein synthesis, since pCP2 was shown to replicate and to be expressed in petite mutants; (3) association of pCP2 with isolated DNA from nuclei as proved by transformation experiments with E. coli.
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 9 (1985), S. 453-461 
    ISSN: 1432-0983
    Schlagwort(e): Recombination ; Repair ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The RAD50 gene in yeast is required for recombination-repair (i.e., the double strand break repair pathway) in mitosis, and for meiotic recombination and sporulation. Both of these processes are complex and seem likely to require a relatively large number of gene products. In order to help define other genes required for recombination and repair processes in yeast, we have isolated extragenic revertants of rad50-4 which restore the ability to grow in the presence of MMS. Evidence from segregation indicates the extragenic revertants fall into at least five loci. Two of them reduce sporulation and spore viability at high temperature; another mutation confers a spontaneous hyperrec phenotype on mitotic cells. Thus, at least three revertants are candidates for mutations which affect recombination functions.
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 9 (1985), S. 547-551 
    ISSN: 1432-0983
    Schlagwort(e): MAL regulatory loci ; Segregation analysis ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary By hybridization with a putative MAL2p regulatory sequence we have identified a 19 kb long BamH1 DNA fragment to contain the MALp sequence in a MAL4 strain. A mixture of recombinant plasmids was prepared by ligation of purified 19 kb BamH1 fragments partially digested with Sau3A into the multicopy vector YEp1357. The source of DNA was a strain carrying the MAL4 locus. Yeast maltose non-fermenting strains were transformed with the plasmid mixture. A recombinant plasmid, pRM-4, containing the MAL4p regulatory gene was isolated that complements the maltose-negative phenotype. The plasmid was shown to confer the ability to synthesize maltase to recipient strains grown under inducing as well as under repressing conditions. The MAL4p regulatory sequence cloned was used as a probe in hybridization experiments to study the degrees of homology between the different MAL regulatory genes. The results showed that the sequence from MAL4 strains is strongly homologous to that of MAL3 strains whereas it shows significant differences to the ones of MAL1 and MAL2 strains. Southern analysis of the segregants of crosses between maltose-positive strains and ma10 strains allowed us to localize the maltase regulatory sequence of each MAL locus within a characteristic BamH1 fragment of genomic DNA hybridizing to the isolated sequence.
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  • 76
    ISSN: 1432-0983
    Schlagwort(e): Catalase ; Saccharomyces cerevisiae ; Heme ; Posttranscriptional control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Compared to wild type cells, strains bearing the pleiotropic regulatory mutations cgr4 or cas1 synthesize apocatalase T at a high rate when grown on high glucose. Like heme-deficient ole3 single mutants, ole3 cgr4 and ole3 cas1 double mutants accumulate no catalase T protein in vivo. This defect introduced by the ole3 mutation is cured by the addition of ALA. By use of the inhibitor actinomycin D we confirm previous findings that ole3 mutants lack catalase T mRNA and show that (i) the ole3 cgr4 and ole3 cas1 double mutants do accumulate catalase T mRNA or mRNA precursor, and (ii) the processing or translation of this RNA or the accumulation of apocatalase T depends on the presence of home.
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 7 (1983), S. 309-312 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; G1 cdc mutants ; tα-factor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Mutants in four G1 cdc strains of Saccharomyces cerevisiae were isolated which failed to show division arrest in the presence of α-factor. The cell cycle properties, terminal arrest morphology and mating competence of these mutants at the restrictive temperature were examined. The G1 specific arrest of the cdc 36 and cdc39 mutants is dependent upon the availability of an intact mating factor response system in Mat a cells. Cdc28 and cdc37 mutants exert their cell cycle blocks independently of the mating factor pathway. It is likely that the nature of the primary growth defect in cdc36 and cdc39 mutants is such that the α-factor pathway is activated in the absence of the pheromone at the restrictive temperature and that G1 arrest is a secondary consequence of a non-cycle specific event in such mutants.
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 7 (1983), S. 235-237 
    ISSN: 1432-0983
    Schlagwort(e): DNA replication ; Shuttle vectors ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Mitotic segregation of three 2 μm-pBR322 chimaeric plasmids (YEp6, YEp21, and YEp24) was studied in yeast. Each displayed a characteristic rate of loss: YEp6 was lost at approximately twice the rate of YEp21 and YEp24. The loss rates were not significantly increased when two chimaeric plasmids were coresident, nor was the endogenous 2 μm plasmid itself displaced. Therefore these plasmids appear to be compatible in yeast.
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 9 (1985), S. 253-257 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; CDC40 ; DNA repair ; Cloning ; Mapping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The cdc40 mutation has been previously shown to be a heat-sensitive cell-division-cycle mutation. At the restrictive temperature, cdc40 cells arrest at the end of DNA replication, but retain sensitivity to hydroxyurea (Kassir and Simchen 1978). The mutation has also been shown to affect commitment to meiotic recombination and its realization. Here we show that mutant cells are extremely sensitive to Methyl-Methane Sulfonate (MMS) when the treatment is carried out at restrictive temperature. Incubation at 37 °C prior to, or after MMS treatment at 23 °C, does not result in lower survival. It is concluded that the CDC40 gene product has a role in DNA repair, possibly holding together or protecting the DNA during the early stages of repair. The CDC40 gene was cloned on a 2.65 kb DNA fragment. A 2 μ plasmid carrying the gene was integrated and mapped to chromosome IV, between trp4 and ade8, by the method of marker loss. Conventional tetrad analysis has shown cdc40 to map 1.7 cM from trp4.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 8 (1984), S. 559-566 
    ISSN: 1432-0983
    Schlagwort(e): DNA repair ; Saccharomyces cerevisiae ; Cloning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Three overlapping plasmids were isolated from a YEp24 library, which restore Rad+ functions to rad6-1 and rad6-3 mutants. Different subclones were made and shown to integrate by homologous recombination at the RAD6 site on chromosome VII, thus verifying the cloned DNA segments to be the RAD6 gene and not a suppressor. The gene resides in a 1.15 kb fragment, which restores Rad+ levels of resistance to U.V., MMS and γ-rays to both rad6-1 and rad6-3 strains. It also restores sporulation ability to rad6-1 diploids. Integrative deletion of the RAD6 gene was shown not to be completely lethal to the yeast. Our results suggest that the RAD6 gene has some cell cycle-specific function(s), probably during late S phase.
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  • 81
    ISSN: 1432-0983
    Schlagwort(e): α-Pheromone-inactivating glycoproteins ; bar1-1 ; Barrier proteins ; Purification ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Two kinds of a-mating-type-specific proteins inactivating α pheromone (α factor) were purified from heat shock extract of MATa cells. Their molecular weights were estimated to be 400,000 and 200,000 by gel filtration. Both proteins were detected in MATa SST1 cells but not in MATα SST1, MATa sst1-1 and MATa/MATα SST1/SST1 cells. In addition, the proteins were detected in matα2-1 SST1 cells but not in matα1-2 SST1 cells. From these results, it is concluded that these proteins are synthesized under the control of the SST1 gene and responsible for the Barrier action of MATa cells. The relationship of these proteins to the secreted Barrier protein having a higher molecular weight is discussed.
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 4 (1981), S. 85-90 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Nuclear isolation ; Percoll ; in vitro Transcription
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A procedure has been developed for the rapid isolation of yeast nuclei in high yield using Percoll gradients. The nuclei are substantially free of cytoplasmic contamination as measured by alcohol dehydrogenase activities, have the typical chromatin digestion pattern when digested with nucleases, are useful for isolation of nuclear proteins and for in vitro transcription experiments.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 7 (1983), S. 57-61 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; DEL1 ; rad ; ste7
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In DEL1 strains of the yeast, Saccharomyces cerevisiae, the iso-1-cytochrome c (CYC1) region is flanked on either side by Tyl elements in direct orientation which promote cyc1 deletions of the bracketed DNA in the haploid cell. In this study, we asked which genes might control this event by testing the possibility that the DEL1 mutation mechanism requires an enzyme (or enzymes) that is also utilized in the repair of damaged DNA. To this end, we independently coupled eight repair mutations, rad3–2, rad4–4, rad6–1, rad6–3, rad9–1, rev3–1, rad50–1, and rad51-1, toDEL1 and asked whether DEL1 was still functional. We found that none of these rad mutations significantly affects the mutation frequency of 10−6-10−5 established in DEL1 strains for the CYC1 locus. Furthermore, we determined that ste7, a temperature-sensitive sterile allele known to alter gene regulation in Ty-mediated mutations, is not required for DEL1 function. Finally, DEL1 is not temperature-sensitive at 23° or 37 °C.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 7 (1983), S. 369-377 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Isoenzymes ; Induction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Tetrad analysis indicates that α-isopropylmalate synthase activity of yeast is determined by two separate genes, designated LEU4 and LEU5. LEU4 is identified as a structural gene. LEU5 either encodes another α-isopropylmalate synthase activity by itself or provides some function needed for the expression of a second structural gene. The properties of mutants affecting the biosynthesis of leucine and its regulation suggest that the expression of LEU1 and LEU2 (structural genes encoding isopropylmalate isomerase and β-isopropylmalate dehydrogenase, respectively) is controlled by a complex of a-isopropylmalate and a regulatory element (the LEU3 gene product). Similarities and differences between yeast and Neurospora crassa with respect to leucine biosynthesis are discussed.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 85
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; TRP3 gene ; Deletion analysis ; Enzyme function
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Two sets of deletions, entering the TRP3 gene of Saccharomyces cerevisiae from the 3′- and the 5′-end were constructed. Complementation analysis with chromosomal trp3A, trp3B and trp3C mutations was done by introducing the 3′- and 5′-truncated gene on a multicopy 2 μm-vector. The N-terminal glutamine amido transferase function is encoded by a DNA fragment of 600–700 bp, and the C-terminal indole-3-glycerol-phosphate synthase function by a DNA fragment of about 900 bp, whereas both functions together are encoded by a contiguous DNA fragment of about 1,500 bp. The bi functional TRP3-peptide thus could be dissected into two catalytically independent peptides in vivo. For the indole-3-glycerol-phosphate synthase activity, independent catalytic activity was also demonstrated in vitro: deletions entering the TRP3 gene from the 5′-end, and lacking large parts of the sequence coding for the glutamine amidotransferase function, still are able to ex press a peptide exhibiting functional indole-3-glycerol phosphate synthase activity in vitro. Deletion plasmids pME505·De1C102·2μm and DelC10·2μm exhibited shorter TRP3 transcripts according to the deleted DNA-fragments (150 and 426 by respectively) but yielded peptides of invariable Mr of 35,000 d. Transcription and translation of these peptides, which probably represent the independently folding indole-3-glycerol-phosphate synthase core are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 86
    ISSN: 1432-0983
    Schlagwort(e): Cephalosporium acremonium ; Mitochondrial DNA ; Autonomous replication sequence ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A fragment of DNA which functions as an autonomous replication sequence in yeast was cloned from Cephalosporium acremonium. Mitochondrial DNA (mtDNA) was isolated from an industrial strain of C. acremonium (08G-250-21) highly developed for the production of the antibiotic, cephalosporin C. Size, 27 kb, and restriction pattern indicated this DNA was identical to mtDNA previously isolated (Minuth et al. 1982) from an ancestral strain (ATTC 14553) which produces very low amounts of cephalosporin C. A 1.9 kb Pst1 fragment of the Cephalosporium mtDNA was inserted into a Pst1 site of the yeast integrative plasmid, Ylp5, to produce a 7.5 kb plasmid, designated pPS1. The structure of pPS1 was verified by restriction analysis and hybridization. PS1 transformed Saccharomyces cerevisiae (DBY-746) to uracil prototrophy at a frequency of 272 transformants/μg DNA. Transformation frequencies of 715 transformants/μg DNA and zero were obtained for the replicative plasmid, YRp7, and the integrative plasmid YIp5, respectively. Southern hybridization and transformation of E. coli by DNA from yeast transformed by pPS1 verified that pPS1 replicates autonomously in yeast. The uracil-independent pPS1-yeast transformants were mitotically unstable. The average retention of pPS1 after three days growth in selective and non-selective medium was 4.5% and 0.4%, respectively, compared to retentions of 4.6% and 0.5% for YRp7. The properties of pPS1 were compared to those of a related plasmid, pCP2. pCP2 was constructed (Tudzynski et al. 1982) by inserting the C. acremonium 1.9 kb Pst1 fragment into the yeast integrative plasmid, pDAM1.
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  • 87
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Yeast vectors ; Cosmids ; nif genes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Two vectors, termed pG63.11 (7.6 Kb) and pHCG3 (9.6 Kb), suitable for yeast transformation have been constructed. The pHCG3 vector has cosmid properties. Both vectors contain a single 3.3 Kb EcoRI-HindIII fragment of yeast origin which carries the yeast URA3 gene (1.1 Kb) and the origin of replication of the 2 µm plasmid (2.2 Kb). They confer ampicillin resistance and they contain 5 unique EcoRI,HpaI,HindIII,BamHI and SalI restriction sites. Cosmid pHCG3 was used to clone the nitrogen fixation (nif) gene cluster of Klebsiella pneumoniae carried by twoHindIII fragments of 17 and 26 Kb, respectively. The resulting cosmid, termed pGPC875 (53 Kb) which conferred a Nif+ phenotype to Escherichia coli, was introduced in yeast by transformation. No acetylene reduction activity was detectable in the transformants. However it was shown that the entire information for nitrogen fixation can be replicated and maintained intact in yeast for more than 50 generations of growth.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 88
    ISSN: 1432-0983
    Schlagwort(e): Suppressors-tRNA ; Saccharomyces cerevisiae ; Nucleotide modification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have examined the tRNAs of two related strains of Saccharomyces cerevisiae, ψ + and ψ −, which differ with respect to an extrachromosomal genetic element that modulates the expression of genotypic and phenotypic suppression. Both the pattern of tRNAs synthesized and the level of nucleotide modification of several selected tRNA species were found to be the same in the ψ + and ψ − strains.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 6 (1982), S. 163-165 
    ISSN: 1432-0983
    Schlagwort(e): Hybridization ; Polyethylene glycol ; Nuclear transfer ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Viable hybrids of Saccharomyces cerevisiae were obtained by transfer of isolated diploid nuclei into haploid protoplasts using a polyethylene glycol (PEG) fusion procedure.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 7 (1983), S. 393-397 
    ISSN: 1432-0983
    Schlagwort(e): Trehalose ; Glycogen ; Sporulation ; Germination ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Mutants with specific lesions were used to differentiate between the functions of glycogen and trehalose in S. cerevisiae. Diploids which harbor the glc1/glc1 mutation depend upon the phosphorylated, less active form of glycogen synthase and show a more active, phosphorylated form, of the enzyme trehalase. These conditions are due to a lesion in the regulating subunit of the cAMP-dependent protein kinase. Such cells are unable to sporulate. Diploids which contain the sst1/sst1 mutation have normal glycogen metabolism but their trehalose-6-phosphate synthase is not active. Such strains sporulate but germination is poor and only one-spore tetrads are formed. These results confirm that glycogen is needed to trigger sporulation while trehalose plays a role in the germination process. Different systems, I and II, of trehalose accumulation were proposed. System I would require the UDPG-linked trehalose synthase, whereas system II would constitute an alternative pathway, specifically induced or activated by the expression of a MAL gene. The presence of system II in its constitutive form in the constructed diploids would favour trehalose synthesis during growth on glucose, however, it did not overcome the glycogen deficiency during sporulation nor the lack of trehalose for germination. It seems that only system I, namely trehalose 6-P-synthase, plays a role in the germination process.
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  • 91
    ISSN: 1432-0983
    Schlagwort(e): Oversecretion mutants ; Protease defect ; Wall glucan defect ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Two chromosomal mutations in yeast that result in oversecretion of the K1 killer toxin protein were examined. A recessive mutation in gene ski5 appears to lead to toxin oversecretion through a defect in a cell surface, PMSF-inhibited protease. A wild type killer strain degraded toxin following synthesis, and degradation could be partially prevented by addition of PMSF to the growth medium. The ski5 mutation caused an approximate ten fold oversecretion of toxin, similar to that seen in a PMSF-treated wild type culture, and no increased oversecretion in the presence of PMSF. The ski5 mutation caused oversecretion of other low molecular weight secreted proteins and appeared to oversecrete the α-factor pheromone, as judged by activity tests. The ski5 mutation was complemented by mutations in ski genes 1–4, and the mutant was not supersensitive to mating pheromones or K2 killer toxin. We also examined killer strains with a mutation in the nuclear gene krel which results in a defective (1→6)-β-D-glucan cell wall receptor for killer toxin. Such strains oversecrete toxin into the growth medium, but also, unexpectedly, oversecrete most other secreted proteins. The defect in (1→6)-β-D-glucan in these mutants appears to perturb the partitioning of secreted proteins between the cell wall and the medium.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 92
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; 5-aminolevulinate synthase ; Cloned gene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have cloned the structural gene HEM1 for 5-aminolevulinate (ALA) synthase from Saccharomyces cerevisiae by transformation and complementation of a yeast hem1–5 mutant which was previously shown to lack ALA synthase activity (Urban-Grimal and Labbe Bois 1981) and had no immunodetectable ALA synthase protein when tested with yeast ALA synthase antiserum. The gene was selected from a recombinant cosmid pool which contained wild-type yeast genomic DNA fragments of an average size of 40 kb. The cloned gene was identified by the restauration.of growth on a non fermentable carbon source without addition of exogenous ALA. Sub cloning of partial Sau3A digests and functional analysis by transformation allowed us to isolate three independent plasmids, each carrying a 6 kb yeast DNA fragment inserted in either orientation into the single BamHI site of the vector pHCG3 and able to complement hem1–5 mutation. Analysis of the three plasmids by restriction endonucleases showed that HEM1 is contained within a 2.9 kb fragment. The three corresponding yeast trans formants present a 1, 2.5 and 16 fold increase in ALA synthase activity as compared to the wild-type strain. The gene product immunodetected in the transformant yeast cells has identical size as the wild-type yeast ALA synthase and its amount correlates well with the increase in ALA synthase activity.
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    Standort Signatur Erwartet Verfügbarkeit
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  • 93
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 6 (1982), S. 159-162 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Transformation ; Gene subcloning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have developped a procedure to delimit the boundaries of a cloned gene carried on a DNA fragment as large as 4 to 5 kilobases. The method consists in the following. Two series of limit digest products generated with a tetranucleotide recognition sequence endonuclease and originating from either of the two ends of this DNA segment are tested for their complementing capacity by yeast transformation. The gene is then delimited by the overlap of the two shortest complementing fragments.
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 9 (1984), S. 107-111 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; 2 μm minichromosomes ; Metrizamide gradients
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Two micrometer minichromosomes from Saccharomyces cerevisiae were isolated without detergent using metrizamide gradients. 2 μm minichromosomes showed a lower density in metrizamide gradients relative to genomic chromatin. Our results suggest a lower ratio of proteins to DNA in 2-μm minichromosomes as compared with genomic chromatin. The procedure described herein yields minichromosomes free of cellular chromatin and ribosomal protein contamination. This method may be useful for the isolation and characterization of other yeast minichromosomes.
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 7 (1983), S. 427-431 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; DNA ; Alkaline elution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The method of analysis of DNA in mammalian cells by alkaline elution from filters (Kohn et al. 1974) was adapted for studies on yeast DNA. By this technique spheroplasts obtained from yeast cells are lysed on filters and single-stranded DNA fragments selectively eluted by alkaline solutions. The procedure was applied to monitor the occurrence of replication intermediates and production of DNA single-strand breakage by MMS, and its repair in growth medium.
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 8 (1984), S. 81-84 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Mitochondrial genes ; Vegetative segregation ; Uniparental inheritance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Zygotes of Saccharomyces cerevisiae that are heteroplasmic for mitochondrial alleles produce diploid progeny that are homoplasmic for one allele or the other, judged by the criterion that upon further subcloning they produce daughter cells of only one phenotype or the other. Here we show that when such cells are subjected to strong selection for the missing allele, it cannot be detected, so that it is probably not present in even a single copy.
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 9 (1985), S. 539-545 
    ISSN: 1432-0983
    Schlagwort(e): Maltose fermentation ; Regulatory sequence ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Yeast genomic libraries containing the MAL1, MAL2-8 c and MAL3 loci were used to transform Ma10 strains to a maltose-positive phenotype. A plasmid called pRM-2 was isolated. mal0 strains synthesized alpha-glucosidase when transformed with this plasmid. Specific activities in the range of 500–1,000 mU/mg protein were detected. An increase of 2–3fold could be observed when the isolated sequence was subcloned in the yeast multicopy vector YEp 1357. Plasmid pRM-2 contains a maltase regulatory sequence as demonstrated by its ability to transform a maltose-negative regulatory mutant to a maltose-positive phenotype. That result also indicated that the mal0 recipient strains are defective in the regulatory gene. Hybridization experiments of genomic EcoRl digests to the isolated plasmid pRM-2 showed characteristic EcoRl fragments in all maltose fermenting strains. Some of the fragments are lacking in the ma10 strains suggesting that the regulatory sequence is located in these fragments. BamHl genomic fragments hybridizing to pRM-2 had different sizes for strains containing different MAL loci. Stable transformants which had integrated pRM-2 either in the TRP1 locus or in the MAL2 locus were obtained. The isolation of the latter type indicates that the cloned sequence is homologous to that present at the MAL2 locus.
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 4 (1981), S. 135-143 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Mitochondria ; Gene cloning ; Transfer RNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have studied the organization and expression of a group of tRNA genes located on a 2,700 base pair portion of the yeast mitochondrial genome between the genetic markers cap (chloramphenicol resistance) and oxil (cytochrome oxidase subunit II). This region is spanned by mitochondrial DNA inserts of two recombinant plasmids, pYm162 and pYm267, which have been extensively mapped and sequenced. This tRNA group is composed of six tRNA genes, coding for tRNA AAR Lys , tRNA AGR Arg , tRNA GGN Gly , tRNA GAY Asp , tRNA AGY Ser , and tRNA CGN Arg . We report the sequence for the majority of the 2,700 base pair region including the genes for all six tRNAs. All six genes are oriented in the same direction and are, therefore, transcribed from the same DNA strand. Further, a comparison of the organization of this region with the analogous region of a related wild type strain shows that the tRNA gene order in the two strains is the same. Five of the six tRNA genes have corresponding transcripts in wild type RNA. Although a potential structural gene for tRNA CGN Arg is present, we do not detect a tRNA CGN Arg gene transcript.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; TRP2 gene ; TRP3 gene ; Cloning in yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary This paper describes the isolation of the TRP2 and the TRP3 genes of Saccharomyces cerevisiae. Two pools of plasmids consisting of BamHI and Sa1GI yeast DNA inserts into the bifunctional yeast — Escherichia coli vector pLC544 (Kingsman et al. 1979) were constructed in E. coli and used for the isolation of the two genes by selection for functional complementation of trp2 and trp3 mutations, respectively, in yeast. The TRP2 gene was isolated on a 6.2 kb BamHl and a 5.8 kb Sa1GI yeast DNA fragment which shared an identical 4.5 kb BamHI-SaIGI fragment. The TRP3 gene was located on a 5.2 kb BamHl fragment. By physical, genetic and physiological experiments it could be shown that the cloned yeast DNA fragments contained the whole structural sequences as well as the regulatory regions of the TRP2 and the TRP3 genes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 7 (1983), S. 433-438 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Yeast transformation ; Yeast autonomously replicating sequences ; Ribosomal RNA genes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have previously demonstrated that the loss of Rcp-CEN3, a centromeric plasmid containing yeast rDNA autonomously replicating sequences (ARS) is as high as around 50% per generation for most yeast strains. In this study we have attempted to elucidate mechanisms underlying the high mitotic instability of Rcp-CEN3. For this purpose a tandem duplication of a rDNA ARS was constructed in Rcp-CEN3. The new plasmid having two ARSs possesses a markedly higher mitotic stability as compared to a monoARS Rcp-CEN3. The mitotic stability of this centromere-containing plasmid which has two replicators corresponds to the calculated value for the mitotic stability of two monoARS plasmids Rcp-CEN3 in given cells. Genetic analysis has demonstrated that both plasmids having one or two ARSs are maintained in the single copy state. These results demonstrate that the mitotic instability of centromeric plasmid Rcp-CEN3 carrying a rDNA ARS is associated with the absence of stringent control of replication from the rDNA ARS. A possible mechanism of replication of the chromosomal rDNA repeats in yeast is discussed in the light of this data.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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