scholarly journals Role of glutathione in heat-shock-induced cell death of Saccharomyces cerevisiae

2000 ◽  
Vol 352 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Kei-ichi SUGIYAMA ◽  
Atsuki KAWAMURA ◽  
Shingo IZAWA ◽  
Yoshiharu INOUE
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitochondrial Dna ◽  
Heat Shock ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type ◽  
Glutathione Synthesis ◽  
Heat Shock Stress ◽  
Shock Stress

Previously we reported that expression of GSH1 (γ-glutamylcysteine synthetase) and GSH2 (glutathione synthetase) of the yeast Saccharomyces cerevisiae was increased by heat-shock stress in a Yap1p-dependent fashion and consequently intracellular glutathione content was increased [Sugiyama, Izawa and Inoue (2000) J. Biol. Chem. 275, 15535–15540]. In the present study, we discuss the physiological role of glutathione in the heat-shock stress response in this yeast. Both gsh1 and gsh2 mutants could acquire thermotolerance by mild heat-shock stress and induction of Hsp104p in both mutants was normal; however, mutant cells died faster by heat shock than their parental wild-type strain. After pretreatment at a sublethal temperature, the number of respiration-deficient mutants increased in a gsh1 mutant strain in the early stages of exposure to a lethal temperature, although this increase was partially suppressed by the addition of glutathione. These results lead us to suspect that an increase of glutathione synthesis during heat-shock stress is to protect mitochondrial DNA from oxidative damage. To investigate the correlation between mitochondrial DNA damage and glutathione, mitochondrial Mn-superoxide dismutase (the SOD2 gene product) was disrupted. As a result, the rate of generation of respiration-deficient mutants of a sod2∆ strain was higher than that of the isogenic wild-type strain and treatment of the sod2∆ mutant with buthionine sulphoximine, an inhibitor of glutathione synthesis, inhibited cell growth. These results suggest that glutathione synthesis is induced by heat shock to protect the mitochondrial DNA from oxidative damage that may lead to cell death.

scholarly journals Role of Saccharomyces cerevisiae Oxidoreductases Bdh1p and Ara1p in the Metabolism of Acetoin and 2,3-Butanediol

2009 ◽  
Vol 76 (3) ◽  
pp. 670-679 ◽  
Author(s):  
Eva González ◽  
M. Rosario Fernández ◽  
Didac Marco ◽  
Eduard Calam ◽  
Lauro Sumoy ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Type Strain ◽  
Wild Type Strain ◽  
Growth Conditions ◽  
Wild Type ◽  
Genome Expression ◽  
Whole Genome Expression ◽  
Histidine Tag ◽  
Butanediol Dehydrogenase

ABSTRACT NAD-dependent butanediol dehydrogenase (Bdh1p) from Saccharomyces cerevisiae reversibly transforms acetoin to 2,3-butanediol in a stereospecific manner. Deletion of BDH1 resulted in an accumulation of acetoin and a diminution of 2,3-butanediol in two S. cerevisiae strains under two different growth conditions. The concentrations of (2R,3R)-2,3-butanediol are mostly dependent on Bdh1p activity, while those of (meso)-2,3-butanediol are also influenced by the activity of NADP(H)-dependent oxidoreductases. One of them has been purified and shown to be d-arabinose dehydrogenase (Ara1p), which converts (R/S)-acetoin to meso-2,3-butanediol and (2S,3S)-2,3-butanediol. Deletion of BDH2, a gene adjacent to BDH1, whose encoded protein is 51% identical to Bdh1p, does not significantly alter the levels of acetoin or 2,3-butanediol in comparison to the wild-type strain. Furthermore, we have expressed Bdh2p with a histidine tag and have shown it to be inactive toward 2,3-butanediol. A whole-genome expression analysis with microarrays demonstrates that BDH1 and BDH2 are reciprocally regulated.

scholarly journals A heat shock-resistant mutant of Saccharomyces cerevisiae shows constitutive synthesis of two heat shock proteins and altered growth.

1984 ◽  
Vol 99 (4) ◽  
pp. 1441-1450 ◽  
Author(s):  
H Iida ◽  
I Yahara
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heat Shock ◽  
Type Strain ◽  
Wild Type Strain ◽  
Growth Control ◽  
Protein S ◽  
Resistant Mutant ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Sulfur Starvation

A heat shock-resistant mutant of the budding yeast Saccharomyces cerevisiae was isolated at the mutation frequency of 10(-7) from a culture treated with ethyl methane sulfonate. Cells of the mutant are approximately 1,000-fold more resistant to lethal heat shock than those of the parental strain. Tetrad analysis indicates that phenotypes revealed by this mutant segregated together in the ratio 2+:2- from heterozygotes constructed with the wild-type strain of the opposite mating type, and are, therefore, attributed to a single nuclear mutation. The mutated gene in the mutant was herein designated hsr1 (heat shock response). The hsr1 allele is recessive to the HSR1+ allele of the wild-type strain. Exponentially growing cells of hsr1 mutant were found to constitutively synthesize six proteins that are not synthesized or are synthesized at reduced rates in HSR1+ cells unless appropriately induced. These proteins include one hsp/G0-protein (hsp48A), one hsp (hsp48B), and two G0-proteins (p73, p56). Heterozygous diploid (hsr1/HSR1+) cells do not synthesize the proteins constitutively induced in hsr1 cells, which suggests that the product of the HSR1 gene might negatively regulate the synthesis of these proteins. The hsr1 mutation also led to altered growth of the mutant cells. The mutation elongated the duration of G1 period in the cell cycle and affected both growth arrest by sulfur starvation and growth recovery from it. We discuss the problem of which protein(s) among those constitutively expressed in growing cells of the hsr1 mutant is responsible for heat shock resistance and alterations in the growth control.

scholarly journals Nuclear Export of Heat Shock and Non-Heat-Shock mRNA Occurs via Similar Pathways

2000 ◽  
Vol 20 (11) ◽  
pp. 3996-4005 ◽  
Author(s):  
Irina E. Vainberg ◽  
Ken Dower ◽  
Michael Rosbash
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heat Shock ◽  
Late Stage ◽  
Nuclear Export ◽  
Type Strain ◽  
Wild Type Strain ◽  
Mrna Export ◽  
Differential Regulation ◽  
Wild Type

ABSTRACT Several studies of the yeast Saccharomyces cerevisiaesupport differential regulation of heat shock mRNA (hs mRNA) and non-hs mRNA nuclear export during stress. These include the finding that hs mRNA export at 42°C is inhibited in the absence of the nucleoporinlike protein Rip1p (also called Nup42p) (C. A. Saavedra, C. M. Hammell, C. V. Heath, and C. N. Cole, Genes Dev. 11:2845–2856, 1997; F. Stutz, J. Kantor, D. Zhang, T. McCarthy, M. Neville, and M. Rosbash, Genes Dev. 11:2857–2868, 1997). However, the results reported in this paper provide little evidence for selective non-hs mRNA retention or selective hs mRNA export under heat shock conditions. First, we do not detect a block to non-hs mRNA export at 42°C in a wild-type strain. Second, hs mRNA export appears to be mediated by the Ran system and several other factors previously reported to be important for general mRNA export. Third, the export of non-hs mRNA as well as hs mRNA is inhibited in the absence of Rip1p at 42°C. As a corollary, we find no evidence for cis-acting hs mRNA sequences that promote transport during heat shock. Taken together, our data suggest that a shift to 42°C in the absence of Rip1p impacts a late stage of transport affecting most if not all mRNA.

scholarly journals Effects of Mutations of RAD50, RAD51, RAD52, and Related Genes on Illegitimate Recombination in Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 383-391 ◽  
Author(s):  
Yasumasa Tsukamoto ◽  
Jun-ichi Kato ◽  
Hideo Ikeda
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Quantitative Analysis ◽  
Structural Analysis ◽  
Recombination Rate ◽  
Type Strain ◽  
Negative Selection ◽  
Wild Type Strain ◽  
Illegitimate Recombination ◽  
Wild Type ◽  
In The Wild

Abstract To examine the mechanism of illegitimate recombination in Saccharomyces cerevisiae, we have developed a plasmid system for quantitative analysis of deletion formation. A can1 cyh2 cell carrying two negative selection markers, the CAN1 and CYH2 genes, on a YCp plasmid is sensitive to canavanine and cycloheximide, but the cell becomes resistant to both drugs when the plasmid has a deletion over the CAN1 and CYH2 genes. Structural analysis of the recombinant plasmids obtained from the resistant cells showed that the plasmids had deletions at various sites of the CAN1-CYH2 region and there were only short regions of homology (1-5 bp) at the recombination junctions. The results indicated that the deletion detected in this system were formed by illegitimate recombination. Study on the effect of several rad mutations showed that the recombination rate was reduced by 30-, 10-, 10-, and 10-fold in the rad52, rad50, mre11, and xrs2 mutants, respectively, while in the rud51, 54, 55, and 57 mutants, the rate was comparable to that in the wild-type strain. The rad52 mutation did not affect length of homology at junction sites of illegitimate recombination.

scholarly journals CaNdt80 Is Involved in Drug Resistance in Candida albicans by Regulating CDR1

2004 ◽  
Vol 48 (12) ◽  
pp. 4505-4512 ◽  
Author(s):  
Chia-Geun Chen ◽  
Yun-Liang Yang ◽  
Hsin-I Shih ◽  
Chia-Li Su ◽  
Hsiu-Jung Lo
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Drug Resistance ◽  
Candida Albicans ◽  
Type Strain ◽  
Antifungal Agents ◽  
Wild Type Strain ◽  
Efflux Pump ◽  
Antifungal Drugs ◽  
Galactosidase Activity ◽  
Wild Type

ABSTRACT Overexpression of CDR1, an efflux pump, is one of the major mechanisms contributing to drug resistance in Candida albicans. CDR1 p-lacZ was constructed and transformed into a Saccharomyces cerevisiae strain so that the lacZ gene could be used as the reporter to monitor the activity of the CDR1 promoter. Overexpression of CaNDT80, the C. albicans homolog of S. cerevisiae NDT80, increases the β-galactosidase activity of the CDR1 p-lacZ construct in S. cerevisiae. Furthermore, mutations in CaNDT80 abolish the induction of CDR1 expression by antifungal agents in C. albicans. Consistently, the Candt80/Candt80 mutant is also more susceptible to antifungal drugs than the wild-type strain. Thus, the gene for CaNdt80 may be the first gene among the regulatory factors involved in drug resistance in C. albicans whose function has been identified.

Identification of cis and trans components of a novel heat shock stress regulatory pathway in Saccharomyces cerevisiae

1993 ◽  
Vol 13 (1) ◽  
pp. 248-256
Author(s):  
N Kobayashi ◽  
K McEntee
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Stress Response ◽  
Heat Shock ◽  
Reporter Gene ◽  
Heat Shock Element ◽  
Cis Acting ◽  
Heat Shock Stress ◽  
Specific Complex ◽  
Cis And Trans ◽  
Shock Stress

The stress-responsive DDR2 gene (previously called DDRA2) of Saccharomyces cerevisiae is transcribed at elevated levels following stress caused by heat shock or DNA damage. Previously, we identified a 51-bp promoter fragment, oligo31/32, which conferred heat shock inducibility on the heterologous CYC1-lacZ reporter gene in S. cerevisiae (N. Kobayashi and K. McEntee, Proc. Natl. Acad. Sci. USA 87:6550-6554, 1990). Using a series of synthetic oligonucleotides, we have identified a pentanucleotide, CCCCT (C4T), as an essential component of this stress response sequence. This element is not a binding site for the well-characterized heat shock transcription factor which recognizes a distinct cis-acting heat shock element in the promoters of many heat shock genes. Here we demonstrate the ability of oligonucleotides containing the C4T sequence to confer heat shock inducibility on the reporter gene and show that the presence of two such elements produces more than additive effects on induction. Gel retardation experiments have been used to demonstrate specific complex formation between C4T-containing fragments and one or more yeast proteins. Formation of these complexes was not competed by fragments containing mutations in the C4T sequence nor by heat shock element-containing competitor DNAs. Fragments containing the C4T element bound to a single 140-kDa polypeptide, distinct from heat shock transcription factors in yeast crude extracts. These experiments identify key cis- and trans-acting components of a novel heat shock stress response pathway in S. cerevisiae.

scholarly journals Disruption of the RAD52 gene alters the spectrum of spontaneous SUP4-o mutations in Saccharomyces cerevisiae.

Genetics ◽  
1989 ◽  
Vol 122 (3) ◽  
pp. 535-542 ◽  
Author(s):  
B A Kunz ◽  
M G Peters ◽  
S E Kohalmi ◽  
J D Armstrong ◽  
M Glattke ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Base Pair ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mutator Phenotype ◽  
In The Wild ◽  
Single Base Pair ◽  
Almost All

Abstract Defects in the RAD52 gene of the yeast Saccharomyces cerevisiae confer a mutator phenotype. To characterize this effect in detail, a collection of 238 spontaneous SUP4-o mutations arising in a strain having a disrupted RAD52 gene was analyzed by DNA sequencing. The resulting mutational spectrum was compared to that derived from an examination of 222 spontaneous mutations selected in a nearisogenic wild-type (RAD52) strain. This comparison revealed that the mutator phenotype was associated with an increase in the frequency of base-pair substitutions. All possible types of substitution were detected but there was a reduction in the relative fraction of A.T----G.C transitions and an increase in the proportion of G.C----C.G transversions. These changes were sufficient to cause a twofold greater preference for substitutions at G.C sites in the rad52 strain despite a decrease in the fraction of G.C----T.A transversions. There were also considerable differences between the distributions of substitutions within the SUP4-o gene. Base-pair changes occurred at fewer sites in the rad52 strain but the mutated sites included several that were not detected in the RAD52 background. Only two of the four sites that were mutated most frequently in the rad52 strain were also prominent in the wild-type strain and mutation frequencies at almost all sites common to both strains were greater for the rad52 derivative. Although single base-pair deletions occurred in the two strains with similar frequencies, several classes of mutation that were recovered in the wild-type background including multiple base-pair deletions, insertions of the yeast transposable element Ty, and more complex changes, were not detected in the rad52 strain.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Role Of Selected Fimbrial Adheins In Pathogenesis Of Acid-Induced Eneterohemorrhagic Escherichia Coli 0157:H7

2021 ◽  
Author(s):  
Shahnaz Haque
Keyword(s):  
Fatty Acid ◽  
Type Strain ◽  
Wild Type Strain ◽  
Short Chain Fatty Acid ◽  
Acid Stress ◽  
Chain Fatty Acid ◽  
Short Chain ◽  
Wild Type ◽  
Food Borne

Enterohemorrhagic Escherichia coli (EHEC) 0157:H7 is a food-borne pathogen that causes hemolytic uremic syndrome and hemorrhagic colitis. The mechanisms underlying the adhesion of EHEC 0157:H7 to intestinal epithelial cells are not well understood. Like other food-borne pathogens, ECEC 0157:H7 must survive the acid stress of the gastric juice in the stomach and short chain fatty acid in the intestine in order to colonize the large intestine. We have found that acid stress and short chain fatty acid stress significantly enhance host-adhesion of EHEC 0157:H7 and also upregulates expression of EHEC fimbrial genes, lpfA1, lpfA2 and yagZ, as demonstrated by our DNA microarray. We now report that disruption of the yagZ (also known as the E. coli common pilus A) gene results in loss of the acid-induced and short chain fatty acid-induced adhesion increase seen for the wild type strain. When the yagZ mutant is complemented with yagZ, the sress-induced and short chain fatty acid-induced adhesion increase seen for the wild type strain. When the yagZ mutant is complemented with yagZ, the stress-induced adhesion pehnotype is restored, confirming the role of yagZ in the acid as well as short chain fatty acid induced adhesion to HEp-2 cells. On the other hand, neither disruption in the long polar fimbria genes lpfA1 or lpfA2 in the wild type showed any effect in adherence to HEp-2 cells; rather displaying a hyperadherant phenotype to HEp-2 cells after acid-induced or short chain fatty acid-induced stress. The results also indicate that acid or short chain fatty acid stress, which is a part of the host's natural defense mechanism against pathogens, may regulate virulence factors resulting in enhanced bacteria-host attachment during colonization in the human or bovine host.

scholarly journals Role of CpALS4790 and CpALS0660 in Candida parapsilosis Virulence: Evidence from a Murine Model of Vaginal Candidiasis

2020 ◽  
Vol 6 (2) ◽  
pp. 86
Author(s):  
Marina Zoppo ◽  
Fabrizio Fiorentini ◽  
Cosmeri Rizzato ◽  
Mariagrazia Di Luca ◽  
Antonella Lupetti ◽  
...  
Keyword(s):  
Cell Wall ◽  
Murine Model ◽  
Type Strain ◽  
Wild Type Strain ◽  
Candida Parapsilosis ◽  
Vaginal Candidiasis ◽  
Phenotypic Characterization ◽  
Wild Type ◽  
Mutant Strains

The Candida parapsilosis genome encodes for five agglutinin-like sequence (Als) cell-wall glycoproteins involved in adhesion to biotic and abiotic surfaces. The work presented here is aimed at analyzing the role of the two still uncharacterized ALS genes in C. parapsilosis, CpALS4790 and CpALS0660, by the generation and characterization of CpALS4790 and CpALS066 single mutant strains. Phenotypic characterization showed that both mutant strains behaved as the parental wild type strain regarding growth rate in liquid/solid media supplemented with cell-wall perturbing agents, and in the ability to produce pseudohyphae. Interestingly, the ability of the CpALS0660 null mutant to adhere to human buccal epithelial cells (HBECs) was not altered when compared with the wild-type strain, whereas deletion of CpALS4790 led to a significant loss of the adhesion capability. RT-qPCR analysis performed on the mutant strains in co-incubation with HBECs did not highlight significant changes in the expression levels of others ALS genes. In vivo experiments in a murine model of vaginal candidiasis indicated a significant reduction in CFUs recovered from BALB/C mice infected with each mutant strain in comparison to those infected with the wild type strain, confirming the involvement of CpAls4790 and CpAls5600 proteins in C. parapsilosis vaginal candidiasis in mice.

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