Alloascoidea hylecoeti gen. nov., comb. nov., Alloascoidea africana comb. nov., Ascoidea tarda sp. nov., and Nadsonia starkeyi‐henricii comb. nov., new members of the Saccharomycotina (Ascomycota)
Abstract
Phylogenetic analysis of concatenated nuclear gene sequences for large and small subunit rRNAs, translation elongation factor 1‐α, and the two large subunits of RNA polymerase II (RPB1, RPB2) demonstrated that species assigned to the yeast genus Ascoidea represent two separate and distantly related clades, that is, Ascoidea (A. asiatica, NRRL Y‐17632, CBS 377.68; A. rubescens, NRRL Y‐17699, CBS 116.35, type species; A. tarda sp. nov., NRRL Y‐2393, CBS 12609, type strain), which is near the genus Saccharomycopsis, and Alloascoidea gen. nov. (Al. africana comb. nov., NRRL Y‐6762‐3, CBS 12606, Al. h...
Source: FEMS Yeast Research - April 8, 2013 Category: Research Authors: Cletus P. Kurtzman, Christie J. Robnett Tags: Research Article Source Type: research
The heme‐binding protein Dap1 links iron homeostasis to azole resistance via the P450 protein Erg11 in Candida glabrata
Abstract
The pathogenic fungus Candida glabrata is relatively resistant to azole antifungals, which target lanosterol 14α‐demethylase (Erg11p) in the ergosterol biosynthesis pathway. Our study revealed that C. glabrata exhibits increased azole susceptibility under low‐iron conditions. To investigate the molecular basis of this phenomenon, we generated a strain lacking the heme (iron protoporphyrin IX)‐binding protein Dap1 in C. glabrata. The Δdap1 mutant displayed growth defects under iron‐limited conditions, decreased azole tolerance, decreased production of ergosterol, and increased accumulation of 14α‐met...
Source: FEMS Yeast Research - April 8, 2013 Category: Research Authors: Naoki Hosogaya, Taiga Miyazaki, Minoru Nagi, Koichi Tanabe, Asuka Minematsu, Yohsuke Nagayoshi, Shunsuke Yamauchi, Shigeki Nakamura, Yoshifumi Imamura, Koichi Izumikawa, Hiroshi Kakeya, Katsunori Yanagihara, Yoshitsugu Miyazaki, Kiyotaka Kugiyama, Shigeru Tags: Research Article Source Type: research
The RAD52 ortholog of Yarrowia lipolytica is essential for nuclear integrity and DNA repair
This article is protected by copyright. All rights reserved. (Source: FEMS Yeast Research)
Source: FEMS Yeast Research - April 8, 2013 Category: Research Authors: E Campos‐Góngora, E Andaluz, A Bellido, J Ruiz‐Herrera, G Larriba Tags: Original Article Source Type: research
Erg11 mutations associated with azole resistance in clinical isolates of Candida albicans
Abstract
The widespread use of azoles has led to increasing azole resistance among Candida albicans strains. One mechanism of azole resistance involves point mutations in the ERG11 gene, which encodes the target enzyme (cytochrome P450 lanosterol 14α‐demethylase). In the present study, we amplified and sequenced the ERG11 gene of 23 C. albicans clinical isolates. Seventeen mutations encoding distinct amino acid substitutions were found, of which seven (K143Q, Y205E, A255V, E260V, N435V, G472R, and D502E) were novel. We further verified the contribution of the amino acid substitutions to azole resistance using site‐di...
Source: FEMS Yeast Research - April 4, 2013 Category: Research Authors: Ming‐Jie Xiang, Jin‐Yan Liu, Pei‐Hua Ni, Shengzheng Wang, Ce Shi, Bing Wei, Yu‐Xing Ni, Hai‐Liang Ge Tags: Research Article Source Type: research
The involvement of GSH in the activation of human Sod1 linked to FALS in chronologically aged yeast cells
In conclusion, our results point to a GSH requirement for hSod1 Ccs1‐independent activation as well as for protection of hSod1 during the aging process. (Source: FEMS Yeast Research)
Source: FEMS Yeast Research - April 4, 2013 Category: Research Authors: Aline A. Brasil, Allan Belati, Sérgio C. Mannarino, Anita D. Panek, Elis C. A. Eleutherio, Marcos D. Pereira Tags: Research Article Source Type: research
Iml3p, a component of the Ctf19 complex of the budding yeast kinetochore is required to maintain kinetochore integrity under conditions of spindle stress
Abstract
The Ctf19 multi‐protein complex of the central kinetochore in Saccharomyces cerevisiae is required for precise chromosome segregation during mitosis. Of 11 proteins of this complex, at least six are required for cell survival when microtubules are defective. To find individual roles of these proteins in kinetochore stability, double deletion mutants of the corresponding genes were constructed in several combinations. The growth phenotype of all the mutants was in accordance with the current model of hierarchical assembly of kinetochore proteins except one that lacked CHL4 and IML3 genes in a tubulin‐defective ...
Source: FEMS Yeast Research - April 2, 2013 Category: Research Authors: Sudeshna Lahiri, Gunjan D. Mehta, Santanu Kumar Ghosh Tags: Research Article Source Type: research
Mitochondrial signaling in Saccharomyces cerevisiae pseudohyphae formation induced by butanol
Abstract
Yeasts growing limited for nitrogen source or treated with fusel alcohols form elongated cells – pseudohyphae. Absence of mitochondrial DNA or anaerobic conditions inhibits this process, but the precise role of mitochondria is not clear. We found that a significant percentage of pseudohyphal cells contained mitochondria with different levels of membrane potential within one cell. An uncoupler carbonyl cyanide p‐(trifluoromethoxy) phenylhydrazone (FCCP), but not the ATP‐synthase inhibitor oligomycin D, prevented pseudohyphal growth. Interestingly, repression of the MIH1 gene encoding phosphatase activator of ...
Source: FEMS Yeast Research - March 19, 2013 Category: Research Authors: Anna N. Starovoytova, Maxim I. Sorokin, Svyatoslav S. Sokolov, Fedor F. Severin, Dmitry A. Knorre Tags: Research Article Source Type: research
Expression level of methanol‐inducible peroxisomal proteins and peroxisome morphology are affected by oxygen conditions and mitochondrial respiratory pathway function in the methylotrophic yeast Candida boidinii
Abstract
In the methylotrophic yeast, Candida boidinii, methanol‐inducible peroxisomal proteins, for example alcohol oxidase (AOD), dihydroxyacetone synthase (DAS), and peroxisomal glutathione peroxidase (Pmp20), were induced only under aerobic conditions, while expression of PMP47 encoding peroxisomal integral membrane protein Pmp47 was independent of oxygen conditions. Expression of the methanol‐inducible peroxisomal enzymes was repressed by inhibition of the mitochondrial respiratory chain. In the respiratory‐deficient (ρ0) mutant strain, their induction was at very low levels despite the presence of oxygen, wher...
Source: FEMS Yeast Research - March 15, 2013 Category: Research Authors: Shuki Fujimura, Hiroya Yurimoto, Shota Kurimoto, Yoshimi Matsufuji, Takashi Ito, Takashi Hayakawa, Noboru Tomizuka, Yasuyoshi Sakai, Tomoyuki Nakagawa Tags: Research Article Source Type: research
The contribution of the nonhomologous region of Prs1 to the maintenance of cell wall integrity and cell viability
Abstract
The gene products of the five‐membered PRS gene family in Saccharomyces cerevisiae have been shown to exist as three minimal functional entities, Prs1/Prs3, Prs2/Prs5, and Prs4/Prs5, each capable of supporting cell viability. The Prs1/Prs3 heterodimer can be regarded as the most important because its loss causes temperature sensitivity. It has been shown that the GFP signal generated by an integrated GFP‐Prs1 construct is lost in the absence of Prs3. In addition to interacting with Prs3, Prs1 also interacts with Slt2, the MAPK of the cell wall integrity (CWI) pathway. Lack of the nonhomologous region (NHR1‐1...
Source: FEMS Yeast Research - March 13, 2013 Category: Research Authors: Eziuche A. Ugbogu, Sonja Wippler, Matthew Euston, Evelyn N. Kouwenhoven, Arjan P.M. Brouwer, Lilian M. Schweizer, Michael Schweizer Tags: Research Article Source Type: research
Molecular characterization of Saccharomyces cerevisiae α‐pheromone by mass spectrometry‐based peptidomics
Abstract
Using modern peptide analytical MS technology (‘Peptidomics’), it is possible to analyze yeast α‐pheromone both qualitatively and semi‐quantitatively directly from conditioned cell culture media. MS/MS analysis shows both forms of α‐pheromone (MFα and MFα') detectable and identifiable straight from WT supernatants. In addition to the mature intact α‐pheromones, also post‐translationally modified α‐pheromone peptides and fragments thereof are found to be present in the culture medium. This molecular analytical technique is complementary to the recently described quantitation method by Rogers e...
Source: FEMS Yeast Research - March 11, 2013 Category: Research Authors: Eda Bener Aksam, Martijn W.H. Pinkse, Peter D.E.M. Verhaert Tags: Short Communication Source Type: research
Genome‐wide investigation of cellular targets and mode of action of the antifungal bacterial metabolite 2,4‐diacetylphloroglucinol in Saccharomyces cerevisiae
In this study, the mode of action of an antifungal metabolite, 2,4‐diacetylphloroglucinol (DAPG), was determined. Applying a combination of genetic and physiological approaches, it was established that this bacterial metabolite acts as a proton ionophore and dissipates the proton gradient across the mitochondrial membrane. The uncoupling of respiration and ATP synthesis ultimately leads to growth inhibition and is the primary toxic effect of DAPG. A genome‐wide screen identified 154 DAPG‐tolerant mutants and showed that there are many alterations in cellular metabolism that can confer at least some degree of toleranc...
Source: FEMS Yeast Research - March 5, 2013 Category: Research Authors: Danielle M. Troppens, Ruslan I. Dmitriev, Dmitri B. Papkovsky, Fergal O'Gara, John P. Morrissey Tags: Research Article Source Type: research
Feasibility of xylose fermentation by engineered Saccharomyces cerevisiae overexpressing endogenous aldose reductase (GRE3), xylitol dehydrogenase (XYL2), and xylulokinase (XYL3) from Scheffersomyces stipitis
In this study, we propose an alternative strategy that employs overexpression of GRE3 coding for endogenous aldose reductase instead of XYL1 to construct efficient xylose‐fermenting S. cerevisiae. Replacement of XYL1 with GRE3 has been regarded as an undesirable approach because NADPH‐specific aldose reductase (GRE3) would aggravate redox balance with xylitol dehydrogenase (XYL2) using NAD+ exclusively. Here, we demonstrate that engineered S. cerevisiae overexpressing GRE3, XYL2, and XYL3 can ferment xylose as well as a mixture of glucose and xylose with higher ethanol yields (0.29–0.41 g g−1 sugars) and produc...
Source: FEMS Yeast Research - March 4, 2013 Category: Research Authors: Soo Rin Kim, Nathania R. Kwee, Heejin Kim, Yong‐Su Jin Tags: Research Article Source Type: research
Adaptive evolution of the lager brewing yeast Saccharomyces pastorianus for improved growth under hyperosmotic conditions and its influence on fermentation performance
Abstract
An adaptive evolution method to obtain stable Saccharomyces pastorianus brewing yeast variants with improved fermentation capacity is described. The procedure involved selection for rapid growth resumption at high osmotic strength. It was applied to a lager strain and to a previously isolated ethanol‐tolerant strain. Fermentation performance of strains was compared at 15 °P wort strength. A selected osmotolerant variant of the ethanol‐tolerant strain showed significantly shorter fermentation time than the parent strain, producing 6.45% alcohol by volume beer in 4‐5 days with mostly similar organoleptic prop...
Source: FEMS Yeast Research - February 16, 2013 Category: Research Authors: J. Ekberg, J. Rautio, L. Mattinen, V. Vidgren, J. Londesborough, B.R. Gibson Tags: Research Paper Source Type: research
Feasibility of xylose fermentation by engineered Saccharomyces cerevisiae overexpressing endogenous aldose reductase (GRE3), xylitol dehydrogenase (XYL2) and xylulokinase (XYL3) from Scheffersomyces stipitis
In this study, we propose an alternative strategy that employs overexpression of GRE3 coding for endogenous aldose reductase instead of XYL1 to construct efficient xylose‐fermenting S. cerevisiae. Replacement of XYL1 with GRE3 has been regarded as an undesirable approach because NADPH‐specific aldose reductase (GRE3) would aggravate redox balance with xylitol dehydrogenase (XYL2) using NAD+ exclusively. Here, we demonstrate that engineered S. cerevisiae overexpressing GRE3, XYL2, and XYL3 can ferment xylose as well as a mixture of glucose and xylose with higher ethanol yields (0.29‐0.41 g/g sugars) and productivities...
Source: FEMS Yeast Research - February 1, 2013 Category: Research Authors: Soo Rin Kim, Nathania Rosaline Kwee, Heejin Kim, Yong‐Su Jin Tags: Research Paper Source Type: research
Heterologous expression of Candida albicans Pma1p in Saccharomyces cerevisiae
Abstract
Candida albicans is a major cause of opportunistic and life‐threatening systemic fungal infections, especially in the immunocompromised. The plasma membrane proton pumping ATPase (Pma1p) is an essential enzyme that generates the electrochemical gradient required for cell growth. We expressed C. albicans Pma1p (CaPma1p) in Saccharomyces cerevisiae to facilitate screening for inhibitors. Replacement of S. cerevisiae PMA1 with C. albicans PMA1 gave clones expressing CaPma1p that grew slowly at low pH. CaPma1p was expressed at significantly lower levels and had lower specific activity than the native Pma1p. It also ...
Source: FEMS Yeast Research - February 1, 2013 Category: Research Authors: Mikhail V. Keniya, Richard D. Cannon, AnBình Nguyen, Joel D. A. Tyndall, Brian C. Monk Tags: Research Paper Source Type: research
