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Vacuolar H+-ATPase (V-ATPase) is thought to play a role in stress tolerance. In this study it was found that bottom-fermenting yeast strains, in which the V-ATPase-related genes DBF2, VMA41/CYS4/NHS5 and RAV2 were overexpressed, exhibited stronger ethanol tolerance than the parent strain and showed increased fermentation rates in a high-sugar medium simulating high-gravity fermentation. Among the strains examined, the DBF2-overexpressing bottom-fermenting yeast strain exhibited the highest ethanol tolerance and fermentation rate in YPM20 medium. Using this strain, high-gravity fermentation was performed by adding sugar to the wort, which led to increased fermentation rates and yeast viability compared with the parent strain. These findings indicate that V-ATPase is a stress target in high-gravity fermentation and suggests that enhancing the V-ATPase activity increases the ethanol tolerance of bottom-fermenting yeast, thereby improving the fermentation rate and cell viability under high-gravity conditions. Copyright © 2012 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

The article offers information on the study that investigates the effects of live Lactobacillus (Lb.) paracasei NFRI 7415 on alcoholic liver disease. It mentions male Fischer rats that were fed with control diet (CD), ethanol diet, or ethanol diet with 20% live Lb. paracasei. It says that total cholesterol concentration in the plasma and liver of the rats reduced after the feeding of Lb. Paracasei. It states that Lb. paracasei could help adjust fatty acid composition and reduced liver damage.

A vanillin-tolerant strain of Saccharomyces cerevisiae was screened and its intracellular ergosterol levels were compared with several laboratory yeast strains to study the potential relationship between ergosterol content and vanillin tolerance. Saccharomyces cerevisiae NBRC1950 was selected as a vanillin-tolerant strain. Its ergosterol content was higher than those of the laboratory strains. The results of DNA microarray and quantitative reverse transcriptase-polymerase chain reaction analysis showed that five genes involved in ergosterol biosynthesis ( ERG28, HMG1, MCR1, ERG5, and ERG7) were upregulated in NBRC 1950 compared with strain X2180, suggesting that high expression of genes involved in ergosterol biosynthesis may cause high ergosterol content in strain NBRC 1950. The S. cerevisiae HX strain, which was a high-ergosterol-containing strain derived from X2180, was more tolerant to vanillin than the parental strain, suggesting that high ergosterol content may, in part, be responsible for vanillin tolerance. These findings provide a biotechnological basis for the molecular engineering of S. cerevisiae with increased tolerance to vanillin. [ABSTRACT FROM AUTHOR]

Yeasts used in bread making are exposed to air-drying stress during dried yeast production processes. To clarify the genes required for air-drying tolerance, we performed genome-wide screening using the complete deletion strain collection of diploid Saccharomyces cerevisiae. The screening identified 278 gene deletions responsible for air-drying sensitivity. These genes were classified based on their cellular function and on the localization of their gene products. The results showed that the genes required for air-drying tolerance were frequently involved in mitochondrial functions and in connection with vacuolar H+-ATPase, which plays a role in vacuolar acidification. To determine the role of vacuolar acidification in air-drying stress tolerance, we monitored intracellular pH. The results showed that intracellular acidification was induced during air-drying and that this acidification was amplified in a deletion mutant of the VMA2 gene encoding a component of vacuolar H+-ATPase, suggesting that vacuolar H+-ATPase helps maintain intracellular pH homeostasis, which is affected by air-drying stress. To determine the effects of air-drying stress on mitochondria, we analysed the mitochondrial membrane potential under air-drying stress conditions using MitoTracker. The results showed that mitochondria were extremely sensitive to air-drying stress, suggesting that a mitochondrial function is required for tolerance to air-drying stress. We also analysed the correlation between oxidative-stress sensitivity and air-drying-stress sensitivity. The results suggested that oxidative stress is a critical determinant of sensitivity to air-drying stress, although ROS-scavenging systems are not necessary for air-drying stress tolerance. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article reports on results of a study of glutamate decarboxylase from a high gamma-aminobutyric acid (GABA)-producer, Lactobacillus paracasei. A description of the experimental set-up and measurement methods is provided. The study concluded that the ability of Lactobacillus paracasei to produce high levels of GABA results to a low Km value and activity at low pH.

Rsp5 is an essential and multi-functional E3 ubiquitin ligase in Saccharomyces cerevisiae. The Ala401Glu rsp5 mutant, which is hypersensitive to various stresses, was isolated previously. To understand the function of Rsp5 in stress responses, suppressor genes whose overexpression allows rsp5A401E cells to grow at a high temperature were screened. The KIN28 and POG1 genes, encoding a subunit of the transcription factor TFIIH and a putative transcriptional activator, respectively, were identified as multicopy suppressors of not only high temperature but also LiCl stresses. The overexpression of Kin28 and Pog1 in rsp5A401E cells led to an increase in the transcriptional level of some stress proteins when exposed to a temperature up-shift. Based on DNA microarray analysis under LiCl stress, it appears that the transcriptional level of some proteasome components is slightly increased in rsp5A401E cells overexpressing Kin28 or Pog1. These results suggest that the overexpression of Kin28 and Pog1 enhances the protein refolding and degradation pathways in rsp5A401E cells. [ABSTRACT FROM AUTHOR]

Yeasts used in bread making are exposed to freeze–thaw stress during frozen-dough baking. To clarify the genes required for freeze–thaw tolerance, genome-wide screening was performed using the complete deletion strain collection of diploid Saccharomyces cerevisiae. The screening identified 58 gene deletions that conferred freeze–thaw sensitivity. These genes were then classified based on their cellular function and on the localization of their products. The results showed that the genes required for freeze–thaw tolerance were frequently involved in vacuole functions and cell wall biogenesis. The highest numbers of gene products were components of vacuolar H+-ATPase. Next, the cross-sensitivity of the freeze–thaw-sensitive mutants to oxidative stress and to cell wall stress was studied; both of these are environmental stresses closely related to freeze–thaw stress. The results showed that defects in the functions of vacuolar H+-ATPase conferred sensitivity to oxidative stress and to cell wall stress. In contrast, defects in gene products involved in cell wall assembly conferred sensitivity to cell wall stress but not to oxidative stress. Our results suggest the presence of at least two different mechanisms of freeze–thaw injury: oxidative stress generated during the freeze–thaw process, and defects in cell wall assembly. [ABSTRACT FROM AUTHOR]

Abstract: Lactobacillus strains that accumulated -aminobutyric acid (GABA) in culture medium were screened to determine strains with high GABA-producing ability. One strain, NFRI 7415, which was isolated from a Japanese traditional fermented fish (funa-sushi), showed the highest GABA-producing ability among the screened strains. Identification tests (i.e., 16S rDNA sequencing and sugar assimilation ability) indicated that NFRI 7415 belongs to Lb. paracasei. The GABA production was further improved by the addition of pyridoxal phosphate to the culture medium and pH regulation of culture medium at pH 5.0. Under optimal cultivation conditions, strain NFRI 7415 produced GABA at a concentration of 302mm when the glutamate concentration in the culture medium was 500mm. [Copyright &y& Elsevier]

Abstract: Freezing tolerance is an important characteristic for baker’s yeast, Saccharomyces cerevisiae, as it is used to make frozen dough. The ability of yeast cells to survive freezing is thought to depend on various factors. The purpose of this work was to study the viability of yeast cells during the freezing process. We examined factors potentially affecting their survival, including the growth phase, ice-seeding temperature, intracellular trehalose content, freezing period, and duration of supercooling. The results showed that the ice-seeding temperature significantly affected cell viability. In the stationary phase, trehalose accumulation did not affect the viability of yeast cells after brief freezing, although it did significantly affect the viability after prolonged freezing. In the log phase, the ice-seeding temperature was more important for cell survival than the presence of trehalose during prolonged freezing. The importance of increasing the extracellular ice-seeding temperature was verified by comparing frozen yeast survival rates in a freezing test with ice-seeding temperatures of −5°C and −15°C. We also found that the cell survival rates began to increase at 3h of supercooling. The yeast cells may adapt to subzero temperatures and/or acquire tolerance to freezing stress during the supercooling. [Copyright &y& Elsevier]

Contamination of Lactobacillus sp. in the fermentation broth of bioethanol production decreases ethanol production efficiency. Although the addition of lactate to the broth can effectively inhibit the growth of Lactobacillus sp., it also greatly reduces the fermentation ability of Saccharomyces cerevisiae. To overcome this conflict, lactate-tolerant yeast strains were screened. Candida glabrata strain NFRI 3164 was found to exhibit both higher levels of lactate tolerance and fermentation ability. Co-cultivation of C. glabrata was performed with Lactobacillus brevis and Lb. fermentum, which were reported as major contaminating bacteria during bioethanol production, in culture medium containing 2% lactate. Under these culture conditions, the growth of Lactobacillus strains was greatly inhibited, but the ethanol production of C. glabrata was not significantly affected. Our data show the possibility of designing an effective fuel ethanol production process that eliminates contamination by Lactobacillus strains through the combined use of lactate addition and C. glabrata. [ABSTRACT FROM AUTHOR]

The aim of this work was to study the molecular breeding of oleaginous filamentous Mortierella alpina for high production of linoleic (LA) or oleic acid (OA). Heterologous expression of the Δ12-desaturase (DS) gene derived from Coprinopsis cinerea in the Δ6DS activity-defective mutant of M. alpina increased the LA production rate as to total fatty acid to 5 times that in the wild strain. By suppressing the endogenous Δ6I gene expression by RNAi in the Δ12DS activity-defective mutant of M. alpina , the OA accumulation rate as to total fatty acid reached 68.0%. The production of LA and OA in these transformants reached 1.44 and 2.76 g/L, respectively, on the 5th day. The Δ6I transcriptional levels of the RNAi-treated strains were suppressed to 1/10th that in the parent strain. The amount of Δ6II RNA in the Δ6I RNAi-treated strain increased to 8 times that in the wild strain. [ABSTRACT FROM AUTHOR]

Psychrotolerant endospore-forming Sporosarcina species have been predominantly isolated from minced fish meat (surimi), which is stored under refrigeration after heat treatment. To develop a better method for preserving surimi-based food products, we studied the growth and fatty acid compositions of the isolated strain S92h as well as Sporosarcina koreensis and Sporosarcina aquimarina at cold and moderate temperatures. The growth rates of strain S92h and S. koreensis were the fastest and slowest at cold temperatures, respectively, although these strains grew at a similar rate at moderate temperatures. In all three strains, the proportions of anteiso-C and unsaturated fatty acids (UFAs) were significantly higher at cold temperatures than at moderate temperatures. Furthermore, supplementation with valine, leucine, and isoleucine resulted in proportional increases in iso-C, iso-C, and anteiso-C, respectively, among the fatty acid compositions of these strains. The proportions of the UFAs were also altered by the supplementation. At cold temperatures, the growth rates of strain S92h and S. koreensis, but not of S. aquimarina, were affected by supplementation with leucine. Supplementation with isoleucine enhanced the growth of S. koreensis at cold temperatures but not that of the other strains. Valine did not affect the growth of any strain. These results indicate that anteiso-C and UFAs both play important roles in the cold tolerance of the genus Sporosarcina and that these bacteria modulate their fatty acid compositions in response to the growth environment. [ABSTRACT FROM AUTHOR]

Co-fermentation of glucose, xylose and l-arabinose from lignocellulosic biomass by an oleaginous yeast is anticipated as a method for biodiesel production. However, most yeasts ferment glucose first before consuming pentoses, due to glucose repression. This preferential utilization results in delayed fermentation time and lower productivity. Therefore, co-fermentation of lignocellulosic sugars could achieve cost-effective conversion of lignocellulosic biomass to microbial lipid. Comprehensive screening of oleaginous yeasts capable of simultaneously utilizing glucose, xylose, and l-arabinose was performed by measuring the concentration of sugars remaining in the medium and of lipids accumulated in the cells. We found that of 1189 strains tested, 12 had the ability to co-ferment the sugars. The basidiomycete yeast Pseudozyma hubeiensis IPM1-10, which had the highest sugars consumption rate of 94.1 %, was selected by culturing in a batch culture with the mixed-sugar medium. The strain showed (1) simultaneous utilization of all three sugars, and (2) high lipid-accumulating ability. This study suggests that P. hubeiensis IPM1-10 is a promising candidate for second-generation biodiesel production from hydrolysate of lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

An inducible promoter is a useful tool for the controlled expression of a given gene. In this report, we describe galactose-dependent promoters for potential use in an oleaginous fungus Mortierella alpina. We cloned the putative promoter regions of two genes encoding galactose metabolic enzymes, GAL1 and GAL10, from the genome of M. alpina 1S-4. The β-glucuronidase ( GUS) reporter gene assay in M. alpina 1S-4 revealed that regulation of these promoters was dependent on the presence of galactose in the medium both with and without other sugars. With the GAL10 promoter, an approximately 50-fold increase of GUS activity was demonstrated by addition of galactose into the culture media at any cultivation phase. The 5′ deletion analysis of the GAL10 promoter revealed that a promoter region of over 2,000 bp length was required for its high-level activity and sufficient inducible response. Significantly, this is the first report of inducible promoters of zygomycetes. The GAL10 promoter will be a valuable tool for gene manipulation in M. alpina 1S-4. [ABSTRACT FROM AUTHOR]

To express a foreign gene effectively, a good expression system is required. In this study, we investigated various promoters as useful tools for gene manipulation in oleaginous fungus Mortierella alpina 1S-4. We selected and cloned the promoter regions of 28 genes in M. alpina 1S-4 on the basis of expression sequence tag abundance data. The activity of each promoter was evaluated using the β-glucuronidase ( GUS) reporter gene. Eight of these promoters were shown to enhance GUS expression more efficiently than a histone promoter, which is conventionally used for the gene manipulation in M. alpina. Especially, the predicted protein 3 and the predicted protein 6 promoters demonstrated approximately fivefold higher activity than the histone promoter. The activity of some promoters changed along with the cultivation phase of M. alpina 1S-4. Seven promoters with constitutive or time-dependent, high-level expression activity were selected, and deletion analysis was carried out to determine the promoter regions required to retain activity. This is the first report of comprehensive promoter analysis based on a genomic approach for M. alpina. The promoters described here will be useful tools for gene manipulation in this strain. [ABSTRACT FROM AUTHOR]

Highlights: [•] The lipid-producing ability of 500 newly isolated yeast strains was evaluated. [•] Lipid content, fatty acid composition, lipid productivity, and biomass were examined. [•] The yeast Cryptococcus musci was capable of the highest lipid productivity. [Copyright &y& Elsevier]

In the representative gut bacterium Lactobacillus plantarum, we identified genes encoding the enzymes involved in a saturation metabolism of polyunsaturated fatty acids and revealed in detail the metabolic pathway that generates hydroxy fatty acids, oxo fatty acids, conjugated fatty acids, and partially saturated trans-fatty acids as intermediates. Furthermore, we observed these intermediates, especially hydroxy fatty acids, in host organs. Levels of hydroxy fatty acids were much higher in specific pathogen-free mice than in germ-free mice, indicating that these fatty acids are generated through polyunsaturated fatty acids metabolism of gastrointestinal microorganisms. These findings suggested that lipid metabolism by gastrointestinal microbes affects the health of the host by modifying fatty acid composition. [ABSTRACT FROM AUTHOR]

Changes in the gene expression of commercial baker''s yeast during an air-drying process, which simulated dried yeast production, were analyzed. K-means clustering suggested that the genes involved in protein folding were transiently up-regulated at early stages, and that the genes involved in fatty acid metabolism were continuously up-regulated. [Copyright &y& Elsevier]

The emergence and spread of mutants resistant to bacteriocins would threaten the safety of using bacteriocins as food preservatives. To determine the physiological characteristics of resistant mutants, mutants of Enterococcus faecium resistant to mundticin KS, a class IIa bacteriocin, were isolated. Two types of mutant were found that had different sensitivities to other antimicrobial agents such as nisin (class I) and kanamycin. Both mutants were resistant to mundticin KS even in the absence of Mg[sup 2+] ions. The composition of unsaturated fatty acids in the resistant mutants was significantly increased in the presence of mundticin KS. The composition of the phospholipids in the two resistant mutants also differed from those in the wild-type strain. The putative zwitterionic amino-containing phospholipid in both mutants significantly increased, whereas amounts of phosphatidylglycerol and cardiolipin decreased. These changes in membrane structure may influence resistance of enterococci to class IIa and class I bacteriocins. [ABSTRACT FROM AUTHOR]

Background: Intravenous glycerol treatment, usually administered in the form of a 5% fructose solution, can be used to reduce intracranial pressure. The administered fructose theoretically influences blood lactate levels, although little is known regarding whether intravenous glycerol treatment causes transient hyperlactatemia. This study aimed to evaluate blood lactate levels in patients who received intravenous glycerol or mannitol. Methods: This single-center prospective observational study was performed at a 14-bed general intensive care unit between August 2016 and January 2018. Patients were excluded if they were < 20 years old or had pre-existing hyperlactatemia (blood lactate > 2.0 mmol/L). The included patients received intravenous glycerol or mannitol to reduce intracranial pressure and provided blood samples for lactate testing before and after the drug infusion (before the infusion and after 15 min, 30 min, 45 min, 60 min, 90 min, 120 min, and 150 min). Results: Among the 33 included patients, 13 patients received 200 mL of glycerol over 30 min, 13 patients received 200 mL of glycerol over 60 min, and 7 patients received 300 mL of mannitol over 60 min. Both groups of patients who received glycerol had significantly higher lactate levels than the mannitol group (2.8 mmol/L vs. 2.2 mmol/L vs. 1.6 mmol/L, P < 0.0001), with the magnitude of the increase in lactate levels corresponding to the glycerol infusion time. There were no significant inter-group differences in cardiac index, stroke volume, or stroke volume variation. In the group that received the 30-min glycerol infusion, blood lactate levels did not return to the normal range until after 120 min. Conclusions: Intravenous administration of glycerol leads to higher blood lactate levels that persist for up to 120 min. Although hyperlactatemia is an essential indicator of sepsis and/or impaired tissue perfusion, physicians should be aware of this phenomenon when assessing the blood lactate levels. [ABSTRACT FROM AUTHOR]

Sake (Japanese rice wine) was fermented in pottery for more than a millennium before wooden barrels were adopted to obtain a greater brewing capacity. Although a recently conducted analysis of sake brewed in pottery indicated that sake brewed in unglazed pottery contains more ethanol than that brewed in glazed pottery, little is known about the characteristics of sake brewed in pottery. In this study, we used two types of ceramic containers of identical size, one glazed and one unglazed, for small-scale sake brewing to evaluate the effects of glazing on fermentation properties. The following parameters were measured continuously in the sake samples over 3 weeks of fermentation: temperature, weight, ethanol concentration, and glucose concentration in sake mash. Taste-sensory values, minerals, and volatile components were also quantified in the final fermented sake mash. The results show that, in the unglazed containers, the temperature of the sake mash was lower and the weight loss was higher compared to the sake mash in the glazed containers. The quantity of ethanol and the levels of Na + , Fe 3+ , and Al 3+ tended to be higher in the sake brewed in the unglazed pottery. A taste-sensory analysis revealed that umami and saltiness were also higher in the samples brewed in the unglazed pottery. These results suggest that glazing affects multiple fermentation parameters and the flavor of sake brewed in pottery. They may also suggest that the materials of the containers used in sake brewing generally affect the fermentation properties.

Three strains of novel oleaginous yeast species were isolated from soil samples collected in Shiga Prefecture, Japan. The sequences of the internal transcribed spacer (ITS) region and the D1/D2 region of the large subunit (LSU) of the rRNA genes indicated that these novel yeast species are members of the genus Hannaella . The results of molecular phylogenetic analysis indicated that strains 38-3 and 8s1 were closely related to Hannaella oryzae . They differed by 10 nucleotide substitutions and one gap (1.77 %) in the D1/D2 region of the LSU of the rRNA genes and by 17-18 nucleotide substitutions and 10-11 gaps (5.45-5.85 %) in the ITS region. Strain 51-4 differed from the type strain of the most closely related species, Hannaella pagnoccae , by 26 nucleotide substitutions (4.46 %) in the D1/D2 region of the LSU of the rRNA genes and by 20 nucleotide substitutions and six gaps (5.42 %) in the ITS region. The names proposed for these previously undescribed species are Hannaella oleicumulans sp. nov. and Hannaella higashiohmiensis sp. nov.

In the traditional (kimoto) method of sake (Japanese rice wine) brewing, Saccharomyces cerevisiae yeast cells are exposed to lactate, which is produced by lactic acid bacteria in the seed mash. Lactate promotes the appearance of glucose-repression-resistant [GAR + ] cells. Herein, we compared the resistance to glucose repression among kimoto, industrial, and laboratory yeast strains. We observed that the frequencies of the spontaneous emergence of [GAR + ] cells among the kimoto strains were higher than those among the industrial and laboratory strains. The fermentation ability of a kimoto yeast (strain U44) was lower than that of an industrial strain (K701), as [GAR + ] cells generally showed slower ethanol production. The addition of lactate decreased the fermentation abilities of the K701 strain by increasing the number of [GAR + ] cells, but it did not affect those of the U44 strain. These results suggest that lactate controlled fermentation by promoting the appearance of [GAR + ] cells in the industrial sake strains but not in the kimoto strains., (© 2023 John Wiley & Sons Ltd.)

Funazushi is a Japanese traditional fermented fish made with boiled rice without the addition of microbial starter cultures. Isolates from various commercial funazushi products, as identified by 16S rDNA sequences, suggested that Lentilactobacillus buchneri strains are major lactic acid bacteria. Based on an analysis of the putative CRISPR (clustered regularly interspaced short palindromic repeat) region, the genetic diversity of L. buchneri strains was examined. The data suggested that the diversity of L. buchneri strains depended on the factories at which funazushi was produced. An analysis of samples during fermentation indicated that the transition of microbes occurred, and L. buchneri was the dominant species. To determine the factors associated with domination, bacteriocin production and environmental stress tolerance, including NaCl and organic acid (lactate and acetate) tolerance, were evaluated. L. buchneri isolates did not produce bacteriocin. Although the isolates did not exhibit NaCl tolerance, they displayed higher lactate tolerance than other lactic acid bacteria isolated during funazushi fermentation. Based on reports that L. buchneri can convert lactate to acetate, the previous and present results suggested that lactate tolerance and lactate conversion in L. buchneri could explain its domination in funazushi. Our study presented a model for the domination mechanisms of specific microbes in fermented foods by spontaneous fermentation., Competing Interests: The authors declare that they do not have any conflict of interest., (© 2022 The Authors. Food Science & Nutrition published by Wiley Periodicals LLC.)

Recently, maintaining a certain oxygen saturation measured by pulse oximetry (SpO 2 ) range in mechanically ventilated patients was recommended; attaching the INTELLiVENT-ASV to ventilators might be beneficial. We evaluated the SpO 2 measurement accuracy of a Nihon Kohden and a Masimo monitor compared to actual arterial oxygen saturation (SaO 2 ). SpO 2 was simultaneously measured by a Nihon Kohden and Masimo monitor in patients consecutively admitted to a general intensive care unit and mechanically ventilated. Bland-Altman plots were used to compare measured SpO 2 with actual SaO 2 . One hundred mechanically ventilated patients and 1497 arterial blood gas results were reviewed. Mean SaO 2 values, Nihon Kohden SpO 2 measurements, and Masimo SpO 2 measurements were 95.7%, 96.4%, and 96.9%, respectively. The Nihon Kohden SpO 2 measurements were less biased than Masimo measurements; their precision was not significantly different. Nihon Kohden and Masimo SpO 2 measurements were not significantly different in the "SaO 2  < 94%" group (P = 0.083). In the "94% ≤ SaO 2  < 98%" and "SaO 2  ≥ 98%" groups, there were significant differences between the Nihon Kohden and Masimo SpO 2 measurements (P < 0.0001; P = 0.006; respectively). Therefore, when using automatically controlling oxygenation with INTELLiVENT-ASV in mechanically ventilated patients, the Nihon Kohden SpO 2 sensor is preferable.Trial registration UMIN000027671. Registered 7 June 2017.