Bioreduction of Some Common Carbonylic Compounds Mediated by Yeasts

2010 ◽  
Vol 65 (1-2) ◽  
pp. 1-9 ◽  
Author(s):  
Javier Silva ◽  
Julio Alarcón ◽  
Sergio A. Aguila ◽  
Joel B. Alderete
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Pichia Pastoris ◽  
Aqueous Medium ◽  
Ethyl Acetoacetate ◽  
Enantiomeric Excess ◽  
Optically Active ◽  
Environmentally Benign ◽  
Wild Type ◽  
Regeneration System ◽  
Type Strains

Bioreduction of several prochiral carbonylic compounds such as acetophenone (1), ethyl acetoacetate (2) and ethyl phenylpropionate (3) to the corresponding optically active secalcohols 1a - 3a was performed using wild-type strains of Pichia pastoris UBB 1500, Rhodotorula sp., and Saccharomyces cerevisiae. The reductions showed moderate to excellent conversion and high enantiomeric excess, in an extremely mild and environmentally benign manner in aqueous medium, using glucose as cofactor regeneration system. The obtained alcohols follow Prelog’s rule, but in the reduction of 1 with P. pastoris UBB 1500 the anti- Prelog enantiopreference was observed

scholarly journals Influences of Histone Stoichiometry on the Target Site Preference of Retrotransposons Ty1 and Ty2 in Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 761-776 ◽  
Author(s):  
Lori A Rinckel ◽  
David J Garfinkel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Promoter Region ◽  
Target Site ◽  
Site Preference ◽  
Wild Type ◽  
Histone Proteins ◽  
Protein Levels ◽  
In The Wild ◽  
Type Strains ◽  
Orientation Bias

Abstract In Saccharomyces cerevisiae, the target site specificity of the retrotransposon Ty1 appears to involve the Ty integration complex recognizing chromatin structures. To determine whether changes in chromatin structure affect Ty1 and Ty2 target site preference, we analyzed Ty transposition at the CAN1 locus in mutants containing altered levels of histone proteins. A Δhta1-htb1 mutant with decreased levels of H2A and H2B histone proteins showed a pattern of Ty1 and Ty2 insertions at CAN1 that was significantly different from that of both the wild-type and a Δhta2-htb2 mutant, which does not have altered histone protein levels. Altered levels of H2A and H2B proteins disrupted a dramatic orientation bias in the CAN1 promoter region. In the wild-type strains, few Ty1 and Ty2 insertions in the promoter region were oriented opposite to the direction of CAN1 transcription. In the Δhta1-htb1 background, however, numerous Ty1 and Ty2 insertions were in the opposite orientation clustered within the TATA region. This altered insertion pattern does not appear to be due to a bias caused by selecting canavanine resistant isolates in the different HTA1-HTB1 backgrounds. Our results suggest that reduced levels of histone proteins alter Ty target site preference and disrupt an asymmetric Ty insertion pattern.

scholarly journals Barrier Activity in Candida albicans Mediates Pheromone Degradation and Promotes Mating

2007 ◽  
Vol 6 (6) ◽  
pp. 907-918 ◽  
Author(s):  
Dana Schaefer ◽  
Pierre Côte ◽  
Malcolm Whiteway ◽  
Richard J. Bennett
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Cell Growth ◽  
Cell Fusion ◽  
Aspartyl Protease ◽  
Wild Type ◽  
Pheromone Activity ◽  
Important Regulator ◽  
Mutant Cells ◽  
Type Strains

ABSTRACT Mating in Candida albicans and Saccharomyces cerevisiae is regulated by the secretion of peptide pheromones that initiate the mating process. An important regulator of pheromone activity in S. cerevisiae is barrier activity, involving an extracellular aspartyl protease encoded by the BAR1 gene that degrades the alpha pheromone. We have characterized an equivalent barrier activity in C. albicans and demonstrate that the loss of C. albicans BAR1 activity results in opaque a cells exhibiting hypersensitivity to alpha pheromone. Hypersensitivity to pheromone is clearly seen in halo assays; in response to alpha pheromone, a lawn of C. albicans Δbar1 mutant cells produces a marked zone in which cell growth is inhibited, whereas wild-type strains fail to show halo formation. C. albicans mutants lacking BAR1 also exhibit a striking mating defect in a cells, but not in α cells, due to overstimulation of the response to alpha pheromone. The block to mating occurs prior to cell fusion, as very few mating zygotes were observed in mixes of Δbar1 a and α cells. Finally, in a barrier assay using a highly pheromone-sensitive strain, we were able to demonstrate that barrier activity in C. albicans is dependent on Bar1p. These studies reveal that a barrier activity to alpha pheromone exists in C. albicans and that the activity is analogous to that caused by Bar1p in S. cerevisiae.

scholarly journals Conservative Duplication of Spindle Poles during Meiosis in Saccharomyces cerevisiae

2001 ◽  
Vol 183 (7) ◽  
pp. 2372-2375 ◽  
Author(s):  
Andreas Wesp ◽  
Susanne Prinz ◽  
Gerald R. Fink
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Spore Formation ◽  
Wild Type ◽  
Body Distribution ◽  
Spindle Poles ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
Type Strains

ABSTRACT During sporulation in diploid Saccharomyces cerevisiae, spindle pole bodies acquire the so-called meiotic plaque, a prerequisite for spore formation. Mpc70p is a component of the meiotic plaque and is thus essential for spore formation. We show here that MPC70/mpc70 heterozygous strains most often produce two spores instead of four and that these spores are always nonsisters. In wild-type strains, Mpc70p localizes to all four spindle pole bodies, whereas in MPC70/mpc70 strains Mpc70p localizes to only two of the four spindle pole bodies, and these are always nonsisters. Our data can be explained by conservative spindle pole body distribution in which the two newly synthesized meiosis II spindle pole bodies of MPC70/mpc70 strains lack Mpc70p.

Xylulose fermentation by mutant and wild-type strains of Zygosaccharomyces and Saccharomyces cerevisiae

2000 ◽  
Vol 53 (4) ◽  
pp. 376-382 ◽  
Author(s):  
A. Eliasson ◽  
E. Boles ◽  
B. Johansson ◽  
M. Österberg ◽  
J. M. Thevelein ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Wild Type ◽  
Type Strains

scholarly journals TWO CHROMOSOMAL GENES REQUIRED FOR KILLING EXPRESSION IN KILLER STRAINS OF SACCHAROMYCES CEREVISIAE

Genetics ◽  
1976 ◽  
Vol 82 (3) ◽  
pp. 429-442
Author(s):  
Reed B Wickner ◽  
Michael J Leibowitz
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Weight ◽  
Mutant Phenotype ◽  
Wild Type ◽  
Double Stranded Rna ◽  
Killer Strain ◽  
Chromosomal Genes ◽  
Complementation Groups ◽  
Killer Plasmid ◽  
Type Strains

ABSTRACT The killer character of yeast is determined by a 1.4 × 106 molecular weight double-stranded RNA plasmid and at least 12 chromosomal genes. Wild-type strains of yeast that carry this plasmid (killers) secrete a toxin which is lethal only to strains not carrying this plasmid (sensitives). —— We have isolated 28 independent recessive chromosomal mutants of a killer strain that have lost the ability to secrete an active toxin but remain resistant to the effects of the toxin and continue to carry the complete cytoplasmic killer genome. These mutants define two complementation groups, kex1 and kex2. Kex1 is located on chromosome VII between ade5 and lys5. Kex2 is located on chromosome XIV, but it does not show meiotic linkage to any gene previously located on this chromosome. —— When the killer plasmid of kex1 or kex2 strains is eliminated by curing with heat or cycloheximide, the strains become sensitive to killing. The mutant phenotype reappears among the meiotic segregants in a cross with a normal killer. Thus, the kex phenotype does not require an alteration of the killer plasmid. —— Kex1 and kex2 strains each contain near-normal levels of the 1.4 × 106 molecular weight double-stranded RNA, whose presence is correlated with the presence of the killer genome.

Multistress resistance of Saccharomyces cerevisiae is generated by insertion of retrotransposon Ty into the 5' coding region of the adenylate cyclase gene

1988 ◽  
Vol 8 (12) ◽  
pp. 5555-5560
Author(s):  
H Iida
Keyword(s):  
Heat Treatment ◽  
Saccharomyces Cerevisiae ◽  
Heat Shock ◽  
Adenylate Cyclase ◽  
Uv Light ◽  
Yeast Cells ◽  
Wild Type ◽  
Coding Region ◽  
Resistant Mutants ◽  
Type Strains

Heat shock-resistant mutants, which were isolated by their ability to withstand lethal heat treatment, were characterized. Resistance was demonstrated to be a consequence of insertion of retrotransposon Ty into either the 5' coding or noncoding region, close to the putative initiation codon of the adenylate cyclase gene CYR1 (or CDC35). These heat shock-resistant mutants contained about threefold lower adenylate cyclase activity than wild-type strains. The mutants were also observed to be resistant to other stresses such as UV light and ethanol. These results demonstrate that multistress resistance, which may confer a survival advantage to yeast cells, can be generated by transposition of a Ty element into CYR1.

scholarly journals Multistress resistance of Saccharomyces cerevisiae is generated by insertion of retrotransposon Ty into the 5' coding region of the adenylate cyclase gene.

1988 ◽  
Vol 8 (12) ◽  
pp. 5555-5560 ◽  
Author(s):  
H Iida
Keyword(s):  
Heat Treatment ◽  
Saccharomyces Cerevisiae ◽  
Heat Shock ◽  
Adenylate Cyclase ◽  
Uv Light ◽  
Yeast Cells ◽  
Wild Type ◽  
Coding Region ◽  
Resistant Mutants ◽  
Type Strains

Heat shock-resistant mutants, which were isolated by their ability to withstand lethal heat treatment, were characterized. Resistance was demonstrated to be a consequence of insertion of retrotransposon Ty into either the 5' coding or noncoding region, close to the putative initiation codon of the adenylate cyclase gene CYR1 (or CDC35). These heat shock-resistant mutants contained about threefold lower adenylate cyclase activity than wild-type strains. The mutants were also observed to be resistant to other stresses such as UV light and ethanol. These results demonstrate that multistress resistance, which may confer a survival advantage to yeast cells, can be generated by transposition of a Ty element into CYR1.

scholarly journals SELECTIVE ABORTION OF TWO NONSISTER NUCLEI IN A DEVELOPING ASCUS OF THE hfd1—1 MUTANT IN SACCHAROMYCES CEREVISIAE

Genetics ◽  
1981 ◽  
Vol 99 (2) ◽  
pp. 197-209
Author(s):  
Susumu Okamoto ◽  
Tetsuo Iino
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mutant Strain ◽  
Recessive Mutation ◽  
Microscopical Examination ◽  
Wild Type ◽  
Selective Abortion ◽  
Dyad Analysis ◽  
Mutant Cells ◽  
Type Strains ◽  
Light Microscopical Examination

ABSTRACT A recessive mutation, hfd1—1, in strain SOS4 of Saccharomyces cerevisiae leads the mutant cells to produce predominantly two-spored asci. Light microscopical examination of Giemsastained cells revealed no significant differences in the meiotic figures between mutant and wild-type strains. However, only two of the four meiotic products in a developing ascus matured to ascospores in SOS4. Dyad analysis was carried out on an hfd1-1 mutant strain heterozygous for three markers, asp5, gal1 and arg4, which are closely linked to their centromeres, and for his4, which is loosely linked to its centromere. The twospored asci produced by the hfd1—1 mutant segregated dominant (+) and recessive (-) alleles of each marker in a 1:1 ratio; they generally contained one + and one - spore for any given marker. The occurrence of rare dyads with two + or two - spores can be explained quantitatively by recombination between the marker and its centromere. From the results of these cytological and genetical analyses, we infer that, in the mutant strain, one genome set is partitioned to each of the four second-meiotic division poles, but only two nonsister genomes are incorporated into mature spores. Thus, the hfd1—1 mutation in SOS4 blocks incorporation of two nonsister nuclei into mature ascospores, but does not block enclosure of the remaining two nonsister nuclei.

scholarly journals ATR1, a Saccharomyces cerevisiae gene encoding a transmembrane protein required for aminotriazole resistance.

1988 ◽  
Vol 8 (2) ◽  
pp. 664-673 ◽  
Author(s):  
S Kanazawa ◽  
M Driscoll ◽  
K Struhl
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Binding Site ◽  
Transmembrane Protein ◽  
Wild Type ◽  
Atp Binding Site ◽  
Activator Protein ◽  
Transcriptional Activator Protein ◽  
Multiple Copies ◽  
Type Strains

In Saccharomyces cerevisiae, 3-amino-1,2,4-triazole (aminotriazole) competitively inhibits the activity of imidazoleglycerolphosphate dehydratase, the product of the HIS3 gene. Wild-type strains are able to grow in the presence of 10 mM aminotriazole because they induce the level of imidazoleglycerolphosphate dehydratase. However, strains containing gcn4 mutations are unable to grow in medium containing aminotriazole because they lack the GCN4 transcriptional activator protein necessary for the coordinate induction of HIS3 and other amino acid biosynthetic genes. Here, we isolated a new gene, designated ATR1, which when present in multiple copies per cell allowed gcn4 mutant strains to grow in the presence of aminotriazole. In wild-type strains, multiple copies of ATR1 permitted growth at extremely high concentrations of aminotriazole (80 mM), whereas a chromosomal deletion of ATR1 caused growth inhibition at very low concentrations (5 mM). When radioactive aminotriazole was added exogenously, cells with multiple copies of ATR1 accumulated less aminotriazole than wild-type cells, whereas cells with the atr1 deletion mutation retained more aminotriazole. Unlike the mammalian mdr or yeast PDR genes that confer resistance to many drugs, ATR1 appears to confer resistance only to aminotriazole. Genetic analysis, mRNA mapping, and DNA sequencing revealed that (i) the primary translation product of ATR1 contains 547 amino acids, (ii) ATR1 transcription is induced by aminotriazole, and (iii) the ATR1 promoter region contains a binding site for the GCN4 activator protein. The deduced amino acid sequence suggests that ATR1 protein is very hydrophobic with many membrane-spanning regions, has several potential glycosylation sites, and may contain an ATP-binding site. We suggest that ATR1 encodes a membrane-associated component of the machinery responsible for pumping aminotriazole (and possibly other toxic compounds) out of the cell.

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