The impact of spaceflight on the immune system has been investigated extensively during spaceflight missions and in model experiments conducted on Earth. Data suggest that the spaceflight environment may affect the development of acquired immunity, and immune responses. Herein we summarize and discuss the influence of the spaceflight environment on acquired immunity. Bone marrow and the thymus, two major primary lymphoid organs, are evidently affected by gravitational change during spaceflight. Changes in the microenvironments of these organs impair lymphopoiesis, and thereby may indirectly impinge on acquired immunity. Acquired immune responses may also be disturbed by gravitational fluctuation, stressors, and space radiation both directly and in a stress hormone-dependent manner. These changes may affect acquired immune responses to pathogens, allergens, and tumors.

c Saccharomyces cerevisiae sake yeast strain Kyokai no. 7 has one of the highest fermentation rates among brewery yeasts used worldwide; therefore, it is assumed that it is not possible to enhance its fermentation rate. However, in this study, we found that fermentation by sake yeast can be enhanced by inhibiting mitophagy. We observed mitophagy in wild-type sake yeast during the brewing of Ginjo sake, but not when the mitophagy gene (ATG32) was disrupted. During sake brewing, the maximum rate of CO 2 production and final ethanol concentration generated by the atg32⌬ laboratory yeast mutant were 7.50% and 2.12% higher than those of the parent strain, respectively. This mutant exhibited an improved fermentation profile when cultured under limiting nutrient concentrations such as those used during Ginjo sake brewing as well as in minimal synthetic medium. The mutant produced ethanol at a concentration that was 2.76% higher than the parent strain, which has significant implications for industrial bioethanol production. The ethanol yield of the atg32⌬ mutant was increased, and its biomass yield was decreased relative to the parent sake yeast strain, indicating that the atg32⌬ mutant has acquired a high fermentation capability at the cost of decreasing biomass. Because natural biomass resources often lack sufficient nutrient levels for optimal fermentation, mitophagy may serve as an important target for improving the fermentative capacity of brewery yeasts. Sake is a traditional Japanese alcoholic beverage produced from steamed rice and koji. During the manufacturing process, glucose is produced (saccharification) from the starch present in rice by the actions of enzymes produced by the koji fungus Aspergillus oryzae. Glucose is fermented to ethanol by Saccharomyces cerevisiae sake yeast strains (1). Sake contains the highest ethanol concentration of all the brewed alcoholic beverages worldwide. This high ethanol concentration is generated by technologies that include successive addition of enzymes and nutrients derived from koji during sake brewing (2, 3), a 3-step pitching process, brewing in winter, and the historical selection of high-ethanol-producing sake yeast strains (1). Sake yeast strains have been selected through a long history of cultivation, ranging from 100 to 400 years. The most frequently used sake yeast at present is Kyokai no. 7 (K7), which was isolated from sake mash in 1946 (4, 5). This strain produces a high concentration of ethanol, because it lacks functions of proteins encoded by MSN4, PPT1, and RIM15, which are required to mount a stress response (6-8). For this reason, researchers in this field believe that it is difficult to further augment the fermentation rate of this sake yeast.Although rice is used as a raw material to brew sake, the surface of rice contains many constituents such as amino acids that impart a heavy and complex taste to sake. Because Japanese consumers tend to prefer a light and clear taste, rice with a polished surface is used for sake brewing. Sake is categorized into...

COMMUNICATIONnanoparticle distance using stimuli-responsive polymers, [ 25,26 ] elastomers, [ 27 ] and DNA [ 28,29 ] have been developed. However, the structures formed using these approaches differ from that of the ideal SERS substrate, which has an extensive regular structure, as described above. Although there is a report on SERS substrates in which gap distance can uniformly change, it did not show the enhancement of trapping effi ciency of large molecules by active gap control. [ 30 ] To address this issue, we have fabricated tunable plasmonic nanostructures with a highly ordered structure through the combination of the self-assembled gold nanoparticles (GNPs) and the use of a hydrogel as a substrate. In our previous report, we demonstrated the transfer of gold dot patterns, fabricated by photolithography and electron-beam lithography, and confi rmed changes in the interval between dots by volume change in the gel. [ 31 ] This result indicates that the gap distance in the GNP-assembled fi lm can be controlled on the gel. Our approach in this study is shown in Scheme 1 . Here, we demonstrate that active gap distance control using tunable plasmonic substrates can signifi cantly intensify the SERS signals of proteins. Therefore, we propose the use of an open-to-closed system for active gap distance control for the sensitive detection of biomacromolecules by SERS.Highly ordered GNP thin fi lm was prepared using the cast method following our previous report. [ 32 ] GNPs (diameter: 20 nm) coated with fl uorinated tetraethylene glycol (FTEG) ligand were cast on piranha-cleaned glass or silicon substrates and dried under ambient conditions. The solvent quickly evaporated and a thin blue-colored fi lm was formed from a redcolored colloidal solution ( Figure 1 B-i, Figure S1A, Supporting Information). This color change resulted from the plasmon coupling effect due to the close proximity of the GNPs. The extinction spectra of this colloidal solution and thin fi lm showed a plasmonic peak shift of ≈90 nm ( Figure S1B, Supporting Information). Atomic force microscopic (AFM) images of the GNP thin fi lm showed that GNPs formed a well-packed, mostly mono-layered, structure with minimum defects on the solid substrates ( Figure S1C, Supporting Information). Scanning electron microscope (SEM) observation of the GNP fi lm prepared on a supported carbon membrane for transmission electron microscopy gave a clear image showing that the interparticle (center-to-center) distance and the gap distance were ≈20.5 nm and ≈1.5 nm, respectively ( Figure S1D, Supporting Information).Transfer of the GNP thin fi lms onto gels was performed by in situ polymerization on the substrates (Figure 1 A). [ 31 ] Molds A surface plasmon resonance is a coherent oscillation of the surface conduction electrons excited by electromagnetic radiation. Research on such light-metal interactions, which are known as plasmonics, has attracted a great deal of attention due to their potential applications in optical or photonic devices and sensors. [1][2][3][4] In...

The mitochondrial states and activities of production yeasts used in the fermentation industry vary according to the availability of oxygen, size of the fermentation tank and temperature of the raw material. However, the involvement of the mitochondrial states of these yeasts in the production profile of organic acids during alcoholic fermentation has not been investigated in detail. In this study, the effects of the mitochondrial state of a sake brewing yeast on the organic acid production profile during an alcoholic fermentation process were investigated. It was elucidated that the mitochondrial state during the propagation stage significantly affected the mitochondrial morphology and the organic acid production profile during the alcoholic fermentation. When yeast mitochondria were active, they were highly branched in the propagation stage, and the yeast cells produced significantly more succinate and less malate. In contrast, when the yeast mitochondria were inactive, they were long and filamentous in appearance, and the yeast produced significantly less succinate and more malate. The change in malic acid content was reversed when an uncoupler of mitochondrial membrane potential, carbonylcyanide p-trifluoromethoxyphenylhydrazone, was added to the culture, indicating that the change in the organic acid production profile could be attributed to mitochondrial activity. Furthermore, the content of malic acid and succinic acid could be converted from a respirative to a fermentative profile by exposing the yeast to a mitochondrion-inactivating environment for 12 or 24 h. Taken together, it was shown that the mitochondrial status of the yeast affects malic acid production during alcoholic fermentation.

The environment experienced during spaceflight may impact the immune system and the thymus appears to undergo atrophy during spaceflight. However, molecular aspects of this thymic atrophy remain to be elucidated. In this study, we analysed the thymi of mice on board the international space station (ISS) for approximately 1 month. Thymic size was significantly reduced after spaceflight. Notably, exposure of mice to 1 × g using centrifugation cages in the ISS significantly mitigated the reduction in thymic size. Although spaceflight caused thymic atrophy, the global thymic structure was not largely changed. However, RNA sequencing analysis of the thymus showed significantly reduced expression of cell cycle-regulating genes in two independent spaceflight samples. These reductions were partially countered by 1 × g exposure during the space flights. Thus, our data suggest that spaceflight leads to reduced proliferation of thymic cells, thereby reducing the size of the thymus, and exposure to 1 × g might alleviate the impairment of thymus homeostasis induced by spaceflight.

Pyruvate is the key substance controlling the formation of diacetyl, acetaldehyde, and acetate during alcoholic fermentation. Here we report the breeding of a low pyruvate-producing sake yeast by isolation of a mutant resistant to ethyl alpha-transcyanocinnamate, an inhibitor of mitochondrial pyruvate transport. Mitochondrial function was involved in resistance to this substance and in the production of pyruvate by the mutants.

Secondary lymphoid organs are critical for regulating acquired immune responses. The aim of this study was to characterize the impact of spaceflight on secondary lymphoid organs at the molecular level. We analysed the spleens and lymph nodes from mice flown aboard the International Space Station (ISS) in orbit for 35 days, as part of a Japan Aerospace Exploration Agency mission. During flight, half of the mice were exposed to 1 g by centrifuging in the ISS, to provide information regarding the effect of microgravity and 1 g exposure during spaceflight. Whole-transcript cDNA sequencing (RNA-Seq) analysis of the spleen suggested that erythrocyte-related genes regulated by the transcription factor GATA1 were significantly down-regulated in ISS-flown vs. ground control mice. GATA1 and Tal1 (regulators of erythropoiesis) mRNA expression was consistently reduced by approximately half. These reductions were not completely alleviated by 1 g exposure in the ISS, suggesting that the combined effect of space environments aside from microgravity could down-regulate gene expression in the spleen. Additionally, plasma immunoglobulin concentrations were slightly altered in ISS-flown mice. Overall, our data suggest that spaceflight might disturb the homeostatic gene expression of the spleen through a combination of microgravity and other environmental changes.

Hot-compressed water treatment of lignocellulose liberates numerous inhibitors that prevent ethanol fermentation of yeast Saccharomyces cerevisiae. Glycolaldehyde is one of the strongest fermentation inhibitors and we developed a tolerant strain by overexpressing ADH1 encoding an NADH-dependent reductase; however, its recovery was partial. In this study, to overcome this technical barrier, redox cofactor preference of glycolaldehyde detoxification was investigated. Glycolaldehyde-reducing activity of the ADH1-overexpressing strain was NADH-dependent but not NADPH-dependent. Moreover, genes encoding components of the pentose phosphate pathway, which generates intracellular NADPH, was upregulated in response to high concentrations of glycolaldehyde. Mutants defective in pentose phosphate pathways were sensitive to glycolaldehyde. Genome-wide survey identified GRE2 encoding a NADPH-dependent reductase as the gene that confers tolerance to glycolaldehyde. Overexpression of GRE2 in addition to ADH1 further improved the tolerance to glycolaldehyde. NADPH-dependent glycolaldehyde conversion to ethylene glycol and NADP+ content of the strain overexpressing both ADH1 and GRE2 were increased at 5 mM glycolaldehyde. Expression of GRE2 was increased in response to glycolaldehyde. Carbon metabolism of the strain was rerouted from glycerol to ethanol. Thus, it was concluded that the overexpression of GRE2 together with ADH1 restores glycolaldehyde tolerance by augmenting the NADPH-dependent reduction pathway in addition to NADH-dependent reduction pathway. The redox cofactor control for detoxification of glycolaldehyde proposed in this study could influence strategies for improving the tolerance of other fermentation inhibitors.