Tomato root-associated harbors genes for catabolizing toxic steroidal glycoalkaloids.

Saponins are a group of plant specialized metabolites with various bioactive properties, both for human health and soil microorganisms. Our previous works demonstrated that is enriched in both soils treated with a steroid-type saponin, such as tomatine, and in the tomato rhizosphere. Despite the importance of saponins in plant-microbe interactions in the rhizosphere, the genes involved in the catabolism of saponins and their aglycones (sapogenins) remain largely unknown.

Generation of new hybrids by crossbreeding between bottom-fermenting yeast strains.

The genetic diversity of bottom-fermenting yeast classified as Saccharomyces pastorianus is poor because strains are restricted to a few genetically distinct groups. Crossbreeding is an effective approach to construct novel yeast strains, but it is difficult because of inefficiency to obtain mating-competent cells (MCCs) of bottom-fermenting yeast. By using mating pheromone-supersensitive mutants, we previously isolated several mating-competent meiotic segregants from two bottom-fermenting yeast strains: high isoamyl acetate-producing KY1247, and low diacetyl-producing KY2645.

An efficient method for isolating mating-competent cells from bottom-fermenting yeast using mating pheromone-supersensitive mutants.

Crossbreeding is an effective approach to construct novel yeast strains with preferred characteristics; however, it is difficult to crossbreed strains of brewer's yeast, especially the bottom-fermenting yeast Saccharomyces pastorianus, because of the relative inefficiency of the available methods to obtain mating-competent cells (MCCs). Here, we describe a productive method for the isolation of MCCs without artificial genetic modification. We focused on the characteristics of two mating pheromone-supersensitive mutants, Δbar1 and Δsst2, that show a growth defect in the presence of the mating pheromone.

Intracellular proteins of ethanol-treated yeast cells involved in iron sorption.

Iron is essential for human health, but it sometimes causes an unpleasant taste, rusty colour and a decrease in the stability of food products. Previously, we found that ethanol-treated yeast (ETY) cells could remove iron from wine and juice, and reduce the fishy aftertaste induced by iron in wine-seafood pairings. However, the mechanism of iron sorption by ETY cells is undefined; thus, there is no indicator that can be used to estimate the iron sorption capacity of these cells.

Novel method to reduce fishy aftertaste in wine and seafood pairing using alcohol-treated yeast cells.

"Fishy aftertaste" is sometimes perceived in wine consumed with seafood. Iron in wine has been reported to be a key compound that produces fishy aftertaste. However, cost-effective methods to remove iron from wine have not been developed.

Multi-locus genotyping of bottom fermenting yeasts by single nucleotide polymorphisms indicative of brewing characteristics.

Yeast plays a capital role in brewing fermentation and has a direct impact on flavor and aroma. For the evaluation of competent brewing strains during quality control or development of novel strains it is standard practice to perform fermentation tests, which are costly and time-consuming. Here, we have categorized DNA markers which enable to distinguish and to screen brewing strains more efficiently than ever before.

A structural and phylogenetic study of the HO gene from Saccharomyces bayanus var. uvarum.

A novel HO gene (Uv-HO) was cloned from the Saccharomyces bayanus var. uvarum (abbreviated as S. uvarum in this study) type strain.

Preparation of artificially spiked soil with polycyclic aromatic hydrocarbons for soil pollution analysis.

To confirm the method for preparing artificially spiked soil with polycyclic aromatic hydrocarbons (PAHs), we tested the homogeneity of PAHs in spiked soils, which were prepared by three different procedures, by using kaolin and ando soil. When the slurry of kaolin and acetone containing PAHs were evaporated by a rotary evaporator at 30 - 35 degrees C, the most homogeneous distribution of PAHs was obtained in the spiked soil. This procedure was applied to the preparation of PAH-spiked soil for natural soil (ando soil).