Together with the worldwide
Washoku
(traditional Japanese foods and drinks) boom, interest in sake, a traditional Japanese alcoholic drink, is increasing around the world. There are few scientific ...analyses and studies on the production of sake or the final product itself. We show the diversity of bacterial contaminants during sake production and investigated the effects of different ingredients on sake (for example, amino acids). The
koji
mold
Aspergillus oryzae
converts rice starch into sugars, and then, the sake yeast
Saccharomyces cerevisiae
converts the sugars to ethanol. Comparative studies of the bacterial flora of different sakes have shown that various bacterial species are detected, but that there are few frequently detected bacteria. In addition, the bacterial flora does not vary much during the process of sake brewing, after the
koji
(steamed rice covered with
koji
mold) and
moto
(fermentation starter) are mixed, suggesting that most bacteria contaminate the sake during the process of
koji
and
moto
production. Thus, there is the possibility that the contaminating bacteria may grow due to a relationship with the
koji
mold and/or the sake yeast. The flavor, taste, and quality of sakes differ, even between the same brands of sakes, which may be attributed to variations in the contaminating bacteria during sake production.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The mechanism of pyruvate-underproduction of aneuploid sake yeast was investigated in this study. In our previous report, we revealed that an increase in chromosome XI decreases pyruvate productivity ...of sake yeast. In this report, we found that increased copy number of CCP1, which is located on chromosome XI and encodes cytochrome-c peroxidase, decreased the pyruvate productivity of sake yeasts. Introducing an extra copy of CCP1 activated respiratory metabolism governed by Hap4 and increased reactive oxygen species. Therefore, it was concluded that increased copy number of CCP1 on chromosome XI activated respiratory metabolism and decreased pyruvate levels in an aneuploid sake yeast. This is the first report that describes a mechanism underlying the improvement of brewery yeast by chromosomal aneuploidy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Addition of amino acids to fermentation media affects the growth and brewing profiles of yeast. In addition, retaining mitochondrial activity during fermentation is critical for the fermentation ...profiles of brewer's yeasts. However, a concrete mechanism linking amino acids in fermentation media with mitochondrial activity during fermentation of brewer's yeasts is yet unknown. Here, we report that amino acids in fermentation media, especially methionine (Met) and glycine (Gly), stabilize mitochondrial activity during fermentation of sake yeast. By utilizing
mutant sake yeast, which shows deteriorated mitochondrial activity, we screened candidate amino acids that strengthened the mitochondrial activity of sake yeast during fermentation. We identified Met and Gly as candidate amino acids that fortify mitochondrial activity in sake yeast during fermentation. To confirm this biochemically, we measured reactive oxygen species (ROS) levels in sake yeast fermented with Met and Gly. Yeast cells supplemented with Met and Gly retained high ROS levels relative to the non-supplemented sake yeast. Moreover, Met-supplemented cells showed a metabolome distinct from that of non-supplemented cells. These results indicate that specific amino acids such as Met and Gly stabilize the mitochondrial activity of sake yeast during fermentation and thus manipulate brewing profiles of yeast.
The first development method of brewery shochu yeast focusing on chromosomal aneuploidy is reported in this study. Euploidy diploid shochu yeast S-3 was treated with a microtubule inhibitor, ...nocodazole, for the purpose of inducing aneuploidy. Next, 2,3,5-triphenyl tetrazolium chloride (TTC) staining and the growth rate were investigated to select aneuploids. Aneuploids were selected at a frequency of 8.2 × 10−4, which was significantly higher than that of the control group, mainly at chromosomes I, II, III, IX, XII, XIII, and XVI. The acquired aneuploids were evaluated for their metabolic and brewing characteristics. A hierarchical cluster analysis based on endogenous metabolite data discriminated euploid S-3 and aneuploids. In addition, principal-component analysis of the constituents of the broth brewed with the strains discriminated between euploid S-3 and aneuploids. Sensory evaluation of the broth brewed with euploid S-3 and aneuploids showed that it tended to differ in aroma and taste. Specific ethanol production rates of the aneuploids were not deteriorated. The method of this selection made it possible to efficiently obtain aneuploids with various brewing characteristics from brewer’s yeast, which do not correspond to genetically modified organisms. This novel breeding method focusing on chromosomal aneuploidy will facilitate the development of novel shochu yeast strains.
The use of interspecific hybrids during the industrial fermentation process has been well established, positioning the frontier of advancement in brewing to capitalize on the potential of ...Saccharomyces hybridization. Interspecific yeast hybrids used in modern monoculture inoculations benefit from a wide range of volatile metabolites that broaden the organoleptic complexity. This is the first report of sake brewing by Saccharomyces arboricola and its hybrids. S. arboricola x S. cerevisiae direct-mating generated cryotolerant interspecific hybrids which increased yields of ethanol and ethyl hexanoate compared to parental strains, important flavor attributes of fine Japanese ginjo sake rice wine. Hierarchical clustering heatmapping with principal component analysis for metabolic profiling was used in finding low levels of endogenous amino/organic acids clustered S. arboricola apart from the S. cerevisiae industrial strains. In sake fermentations, hybrid strains showed a mosaic profile of parental strains, while metabolic analysis suggested S. arboricola had a lower amino acid net uptake than S. cerevisiae. Additionally, this research found an increase in ethanolic fermentation from pyruvate and increased sulfur metabolism. Together, these results suggest S. arboricola is poised for in-depth metabolomic exploration in sake fermentation.
For the development of a hydrogen energy society, understanding hydrogen-assisted fatigue crack propagation is crucial. Hydrogen-assisted fatigue crack propagation exhibits an exceptionally rapid ...growth rate, with only small plastic deformation observed at the macroscopic level. Nevertheless, the presence of dislocation structures, typically associated with conventional fatigue failure, has been reported near the crack tip. Explaining this phenomenon solely based on hydrogen-induced softening or hardening is challenging. Therefore, this study focuses on the newly proposed concept of temporary hardening resulting from hydrogen-induced pinning and depinning. In this research, we conducted a numerical analysis using an elastoplastic analysis coupled with hydrogen diffusion analysis to simulate the pinning and depinning effects caused by hydrogen. Our simulation results demonstrated that hydrogen-induced pinning and depinning led to higher strains at the crack tip compared to cases without these effects, resulting in small-scale macroscopic plastic deformation.
•We focused on the dislocation pinning-depinning by hydrogen.•The dislocation pinning-depinning by hydrogen decreases the plastic-zone size.•The increase in the depinning strength effectively localizes the plastic zone.•The dislocation pinning–depinning increases the local plastic strain.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We report a case of downbeat nystagmus (DBN) and tremor in a patient who visited our hospital 6 months after the onset of dizziness. Hypomagnesemia was considered as a possible cause based on the ...results of a serum magnesium examination. Intravenous magnesium sulfate was therefore administered to correct the patient's serum magnesium level. The DBN and tremor almost completely disappeared the following day. Although there have been several case reports of dizziness in association with hypomagnesemia, the authors did not mention DBN. This report is considered to be the first DBN case caused by hypomagnesemia in Japan. Cases of hypomagnesemia, which may be induced by several factors－including excessive diet, long-term proton-pump inhibitor (PPI) intake, and type 2 diabetes－are increasing. In cases of DBN, a serum magnesium examination is as important as head MRI.
The most common early complication after total laryngectomy is pharyngocutaneous fistula (PCF). However, there are no reports of PCF after total laryngectomy caused by ‘Kombu’ (edible seaweed) as a ...foreign body in the digestive tract. A 68-year-old Japanese man had undergone total laryngectomy 5 years previously. He presented with PCF, neck swelling and pain. Video endoscopy showed that a dark green foreign body obstructed the digestive tract. PCF was successfully treated via emergency surgery comprising abscess drainage, foreign body removal and fistula closure. The foreign body was kombu. Clinicians who perform total laryngectomy should know the potential dangers of consuming hygroscopic food items that can cause bolus obstruction of the upper digestive tract and pharyngeal abscess and perforation.
The usefulness of endoscopic endonasal skull base surgery (EES) and concurrent craniotomy was discussed in our three cases of experiences of fibrous dysplasia (FD). Case 1: Eight years-old girl was ...presented with progression of visual deterioration. Bilateral optic canal was narrowed by FD in sphenoid bone. EES was performed to reduce the volume around the optic canal but restenosis was observed in three years. ESS was performed again and opened the optic canal bilaterally. Her visual field was expanded after the 2nd surgery although the visual acuity was not improved. Case 2: Thirteen year-old girl was presented with progressive visual loss of her right eye. FD was extended in the right sphenoid and temporal bone to the nasal cavity. The mass was removed by EES and concurrent craniotomy and optic canal was decompressed almost the entire circumference via trans-cranial and trans- sphenoidal routes. Her visual acuity was improved postoperatively. Case 3: Twelve year-old girl was presented with exophthalmos and bilateral visual loss. Huge FD was observed in the nasal cavity. After embolization of spheno-palatine artery, majority of the mass was removed by combined EES and craniotomy. Optic canal was decompressed almost entirely and her visual field defect was improved. Simultaneous combination of EES and craniotomy for skull base FD was more effective than each single method in terms of entire optic canal decompression, orientation of each approach and control of intraoperative bleeding. Functional cooperation of otolaryngologist and neurosurgeon was important.
Dodatak aminokiselina u fermentacijsku podlogu utječe na rast i aktivnost kvasca, a zadržavanje aktivnosti mitohondrija tijekom alkoholnog vrenja je kritično za aktivnost pivskog kvasca. Međutim, ...mehanizam djelovanja aminokiselina u fermentacijskoj podlozi i njihov utjecaj na aktivnost mitohondrija pivskog kvasca tijekom vrenja još uvijek nije poznat. U ovom radu smo utvrdili da aminokiseline u fermentacijskoj podlozi, osobito metionin i glicin, stabiliziraju aktivnost mitohondrija kvasca tijekom proizvodnje pića sake. Pomoću mutanta atg32△, koji ima narušenu aktivnost mitohondrija, istražili smo aminokiseline koje povećavaju aktivnost mitohondrija kvasca tijekom vrenja. Identificirali smo metionin i glicin kao aminokiseline koje bi mogle povećati aktivnost mitohondrija kvasca tijekom proizvodnje pića sake. Da bismo to potvrdili, izmjerili smo količinu reaktivnih oblika kisika u kvascu nakon vrenja u podlozi s metioninom i glicinom. Kvasac koji je fermentirao u podlozi s metioninom i glicinom zadržao je relativno veliku količinu reaktivnih oblika kisika u usporedbi s kvascem koji je fermentirao u podlozi bez dodatka aminokiselina. Osim toga, stanice koje su fermentirale u podlozi s dodatkom metionina imale su različit metabolom od stanica koje su fermentirale u podlozi bez dodatka aminokiseline. Rezultati pokazuju da određene aminokiseline, poput metionina i glicina, stabiliziraju aktivnost mitohondrija kvasca tijekom proizvodnje pića sake i na taj način upravljaju aktivnošću kvasca.
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