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.

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, whereas the expression of PMP47 was unaffected.

Alteration of ethanol tolerance caused by the deficiency in the genes associated with histone deacetylase complex in budding yeast.

Upon exposure to 8% ethanol, survival and growth of yeast strains deficient in histone deacetylase complex genes was examined. Of the 18 mutants tested, the Δsir3 and Δsir4 strains showed higher resistance to ethanol, while the Δrco1, Δhos3, Δhda2, and Δhst1 strains were more sensitive than the wild type. Furthermore, these ethanol-resistant patterns varied under aerobic and anaerobic culture conditions.

Molecular characterization of the PEX14 gene from the methylotrophic yeast Pichia methanolica.

In this study, we describe the molecular characterization of the PmPEX14 gene encoding the peroxisomal membrane protein from the methylotrophic yeast Pichia methanolica. The pex14Δ strain of P. methanolica lost its ability to grow on methanol and oleate but grew normally on glucose.

Transcription factor Stb5p is essential for acetaldehyde tolerance in Saccharomyces cerevisiae.

Transcription factor Stb5p, previously known as one of the multidrug resistance gene regulators in Saccharomyces cerevisiae, was shown here to play an essential role in acetaldehyde tolerance. A mutant strain, Δstb5 exhibited increased acetaldehyde sensitivity, and failed to induce genes such as GND1, TKL1 and TAL1 involved in the pentose phosphate pathway (PPP) upon acetaldehyde stress. Using this strain it was revealed that Stb5p acts as a repressor for PGI1 encoding glucose-6-phosphate isomerase under acetaldehyde stress.

The peroxisomal catalase gene in the methylotrophic yeast Pichia methanolica.

In this paper, we describe the CTA1 gene, which encodes a peroxisomal catalase in the methylotrophic yeast Pichia methanolica. The P. methanolica CTA1 gene (PmCTA1) comprises a 1,530-bp open reading frame corresponding to a protein of 510 amino acid residues, and its deduced amino acid sequence shows high similarity to those of Cta1ps from other methylotrophic yeasts (about 79%).

Molecular characterization of two genes with high similarity to the dihydroxyacetone synthase gene in the methylotrophic yeast Pichia methanolica.

The methylotrophic yeast Pichia methanolica possesses two genes, PmDAS1 and PmDLP1, whose amino acid sequences show high similarity to dihydroxyacetone synthase (DAS), the formaldehyde-fixing enzyme for methanol metabolism within the peroxisome. The PmDAS1 and PmDLP1 genes encode 709 and 707 amino acid residues respectively, and PmDas1p contains a type-1 peroxisomal targeting signal (PTS1), while PmDlp1p does not. Upon phylogenetic analysis, PmDas1p fit into the DAS group with other DASs, while PmDlp1p was grouped with the DAS-like proteins (DLP) of non-methylotrophic yeasts and fungi, a branch of the phylogenetic tree independent of the DAS and transketolase (TK) groups.

Flavobacterium algicola sp. nov., isolated from marine algae.

A rod-shaped Gram-staining-negative, non-motile, aerobic and fucoidan-digesting strain, designated TC2(T), was isolated from marine algae collected from the coast of the Sea of Okhotsk at Abashiri, Hokkaido, Japan. The bacterium formed yellow, translucent, circular and convex colonies. Comparative 16S rRNA gene sequence analysis indicated that the strain belonged to the genus Flavobacterium, with the highest sequence similarities of 97.

Acetaldehyde tolerance in Saccharomyces cerevisiae involves the pentose phosphate pathway and oleic acid biosynthesis.

To identify genes responsible for acetaldehyde tolerance, genome-wide screening was performed using a collection of haploid Saccharomyces cerevisiae strains deleted in single genes. The screen identified 49 genes whose deletion conferred acetaldehyde sensitivity, and these were termed the genes required for acetaldehyde tolerance. We focused on six of these genes required for acetaldehyde tolerance, ZWF1, GND1, RPE1, TKL1 and TAL1, which encode enzymes in the pentose phosphate pathway (PPP), and OAR1, which encodes for NADPH-dependent 3-oxoacyl-(acyl-carrier-protein) reductase.

Molecular characterization of the PEX5 gene encoding peroxisomal targeting signal 1 receptor from the methylotrophic yeast Pichia methanolica.

In this study, we describe the molecular characterization of the PEX5 gene encoding the peroxisomal targeting signal 1 (PTS1) receptor from the methylotrophic yeast Pichia methanolica. The P. methanolica PEX5 (PmPEX5) gene contains a open reading frame corresponding to a gene product of 646 amino acid residues, and its deduced amino acid sequence shows a high similarity to those of Pex5ps from other methylotrophic yeasts.

Distribution, diversity and regulation of alcohol oxidase isozymes, and phylogenetic relationships of methylotrophic yeasts.

In this study, we attempted to classify the methylotrophic yeasts based on diversities of alcohol oxidase (AOD), i.e. zymogram patterns and partial amino acid sequences.

Peroxisomal metabolism is regulated by an oxygen-recognition system through organelle crosstalk between the mitochondria and peroxisomes.

In the present study using Pichia methanolica, it was found that expressions of methanol-metabolic enzymes were strictly regulated by the presence of oxygen, and that induction of alcohol oxidase (AOD) isozymes was completely dependent on oxygen concentrations. A proportion of AOD-isozyme species responded to oxygen conditions, e.g.

Molecular characterization of the Tim9 homologue from the methylotrophic yeast Pichia methanolica.

In this paper we describe molecular characterization of the TIM9 gene encoding the essential mitochondrial inner-membrane protein in the methylotrophic yeast Pichia methanolica. PmTIM9 contains two exons corresponding to a gene product of 89 amino acid residues and a 140 bp intron. The deduced amino acid sequence exhibited high identity to those of other yeast Tim9ps, and possessed two CX(3)C motifs that contained two cysteine residues conserved among small Tim family proteins.

Regulation of two distinct alcohol oxidase promoters in the methylotrophic yeast Pichia methanolica.

In this study, two Pichia methanolica alcohol oxidase (AOD) promoters, P(MOD1) and P(MOD2), were evaluated in a promoter assay system utilizing the acid phosphatase (AP) gene from Saccharomyces cerevisiae (ScPHO5) as a reporter. Heterologous gene expression driven by the P(MOD1) and P(MOD2) promoters was found to be strong and tightly regulated by carbon source at the transcriptional level. P(MOD1) was induced not only by methanol but also by glycerol.

Pectin utilization by the methylotrophic yeast Pichia methanolica.

The methylotrophic yeast Pichia methanolica was able to grow on pectic compounds, pectin and polygalacturonate, as sole carbon sources. Under the growth conditions used, P. methanolica exhibited increased levels of pectin methylesterase, and pectin-depolymerizing and methanol-metabolizing enzyme activities.

Molecular characterization of the glutathione-dependent formaldehyde dehydrogenase gene FLD1 from the methylotrophic yeast Pichia methanolica.

In this paper, we describe molecular characterization of the FLD1 gene, which encodes glutathione-dependent formaldehyde dehydrogenase (FLD), from the methylotrophic yeast Pichia methanolica. The P. methanolica FLD1 gene contains two exons corresponding to a gene product of 380 amino acid residues and a 225 bp intron, respectively, and its deduced amino acid sequence shows high similarity to those of Fld1ps from other methylotrophic yeasts (80-88%).