Isolation and characterization of Zygosaccharomyces sp. yeast strains from miso.

There is currently great interest in the salt-tolerant yeast strains used to produce miso and soy sauce. Since the isolation of Zygosaccharomyces sp. strain from Japanese miso more than 60 years, several hybrid strains have been identified in fermented foods.

Regulation of mating and mating-type-specific genes in Zygosaccharomyces sp. yeast.

Zygosaccharomyces sp. is an industrially important yeast for the production traditional fermented foods in Japan. At present, however, there is no easy method for mating Zygosaccharomyces sp.

Tetrad analysis of sake yeast and identification of an RFLP marker for the absence of phenolic off-flavour production.

Mating is a promising breeding method for industrial yeast. Although sake yeast has a low spore-formation ability, segregants exhibiting a mating type have been isolated from sake yeast K7. Here, we constructed zygotes from a cross between those segregants and a laboratory yeast strain.

Variations in mating-type-like (MTL) loci direct PCR-based tracking of Zygosaccharomyces strains formed by mating.

Variations of chromosomal structures and nucleotide sequences around mating-type-like (MTL) loci among Zygosaccharomyces species have been reported. We have analyzed these differences in more detail and, on the basis of PCR- and next-generation sequencing data, we describe the MTL loci on chromosomes C and F for Z. rouxii type-strain NBRC1130, Z.

Nitrogen starvation induces expression of Lg-FLO1 and flocculation in bottom-fermenting yeast.

When exponentially growing cells of bottom-fermenting yeast were starved for nitrogen or were grown on proline (a non-preferred nitrogen source), flocculation was induced. This flocculation was not induced by starvation for either carbon or amino acids. Expression of Lg-FLO1, which is required for flocculation of bottom-fermenting yeast, was also found to be induced by starvation for nitrogen.

Construction of a URA3 deletion strain from the allotetraploid bottom-fermenting yeast Saccharomyces pastorianus.

The bottom-fermenting lager yeast Saccharomyces pastorianus has been proposed to be allotetraploid, containing two S. cerevisiae (Sc)-type and two S. bayanus (Sb)-type chromosomes.

Whole-genome sequencing of sake yeast Saccharomyces cerevisiae Kyokai no. 7.

The term 'sake yeast' is generally used to indicate the Saccharomyces cerevisiae strains that possess characteristics distinct from others including the laboratory strain S288C and are well suited for sake brewery. Here, we report the draft whole-genome shotgun sequence of a commonly used diploid sake yeast strain, Kyokai no. 7 (K7).

Role of bottom-fermenting brewer's yeast KEX2 in high temperature resistance and poor proliferation at low temperatures.

Variants of bottom-fermenting brewer's yeast that grew at high temperatures and showed poor proliferation and fermentation at low temperatures were isolated. Similar variants of laboratory yeast were also isolated and found to be incapable of mating. The KEX2 gene was cloned by complementation.

HorC, a hop-resistance related protein, presumably functions in homodimer form.

To determine whether two HorC molecules coordinately form a single unit, the functional properties of covalently linked dimers of HorC encoded by tandemly fused horC genes were studied. Lactobacillus brevis introduced with the fused horC genes and a single horC gene exhibited same degree of resistance to hop compounds and cetyltrimethylammonium bromide. This suggests that HorC functions as a homodimer.

Rapid detection and identification of beer-spoilage lactic acid bacteria by microcolony method.

We evaluated a microcolony method for the detection and identification of beer-spoilage lactic acid bacteria (LAB). In this approach, bacterial cells were trapped on a polycarbonate membrane filter and cultured on ABD medium, a medium that allows highly specific detection of beer-spoilage LAB strains. After short-time incubation, viable cells forming microcolonies were stained with carboxyfluorescein diacetate (CFDA) and counted with muFinder Inspection System.

Modified multiplex PCR methods for comprehensive detection of Pectinatus and beer-spoilage cocci.

Specific PCR primers were designed based on the 16S rRNA genes of recently proposed beer-spoilage species, Pectinatus haikarae, Megasphaera sueciensis, and M. paucivorans, and two sets of our previously reported multiplex PCR methods for Pectinatus spp. and beer-spoilage cocci were reconstructed.