Changes in the Quality and Microflora of Yellowtail Seriola quinqueradiata Muscles during Cold Storage.

We evaluated the changes in the quality and microflora of yellowtail flesh cold-stored until spoilage. Based on the sensory evaluation, odor palatability was deemed unacceptable for dark muscle (DM) and the dorsal part of the ordinary muscle (OD) after >10 days and 14 of storage, respectively. Log 7 CFU/g in DM as well as OD was obtained on days 10 (Aeromonas spp.) and 14 (Enterobacteriaceae and Pseudomonas spp.) of storage, whereas log 5 (Brocothrix thermosphacta) and 6 (H2S-producing bacteria) CFU/g in them were obtained on day 14 of storage. In these bacteria, the viable bacterial counts of Pseudomonas spp. and Aeromonas spp. in DM were significantly higher than those in OD only at some storage times. Amplicon sequencing revealed that in both muscles, Pseudomonas became predominant after storage, with greater than 90% recorded after more than 10 days of storage. The relative abundances of Acinetobacter, Unclassified Gammaproteobacter, and Shewanella were relatively high in both muscles after more than 10 days of storage; however, these values were less than 5%. Ethyl butyrate in the OD and DM and 2,3-butanedione in the OD were first detected on days 14 and 10 of storage, respectively. Acetoin in the OD increased by 81-fold after 14 days of storage and was significantly increased in the DM after more than 10 days compared with the amount detected pre-storage. Volatiles, such as (E)-2-pentenal in the OD and 1-pentanol in the DM, decreased and increased linearly, respectively, throughout the 14-day storage period. Altogether, these volatile components may cause quality deterioration due to spoilage and/or lipid oxidation during cold storage of the OD and DM.

Changes in extractive components and bacterial flora in live mussels Mytilus galloprovincialis during storage at different temperatures.

To estimate the quality of mussels during storage, the mortality, succinate dehydrogenase (SDH) activity, extractive components, viable bacterial count (VBC), and bacterial flora of live mussels were investigated. The hierarchical cluster analysis, based on extractive components and VBC, taste active value (TAV), and equivalent umami concentration (EUC), suggested that metabolite composition, bacterial, and taste changing patterns of samples stored at 5 and 10°C differed from those stored at 0°C. The mortality of mussels stored at 5 and 10°C was lower than those at 0°C. The gills of live mussels stored at 0°C for more than 7 days exhibited significantly lower SDH activity than those stored at 5 and 10°C. There was no significant difference in EUC among the samples stored at different temperatures, but a significantly higher TAV of Ala and succinic acid was observed in live mussels after 12 days of storage at 5 and 10°C than in those stored at 0°C. Next-generation sequencing analysis showed that samples stored at 5 and 10°C lost bacterial diversity, and their bacterial flora changed compared to that before storage. Considering these results, the most suitable storage condition to maintain high quality for live mussels is 5°C for less than 7 days.

Structural basis for activation of DNMT1.

DNMT1 is an essential enzyme that maintains genomic DNA methylation, and its function is regulated by mechanisms that are not yet fully understood. Here, we report the cryo-EM structure of human DNMT1 bound to its two natural activators: hemimethylated DNA and ubiquitinated histone H3. We find that a hitherto unstudied linker, between the RFTS and CXXC domains, plays a key role for activation. It contains a conserved α-helix which engages a crucial "Toggle" pocket, displacing a previously described inhibitory linker, and allowing the DNA Recognition Helix to spring into the active conformation. This is accompanied by large-scale reorganization of the inhibitory RFTS and CXXC domains, allowing the enzyme to gain full activity. Our results therefore provide a mechanistic basis for the activation of DNMT1, with consequences for basic research and drug design.

Association of eating habits and Firmicutes/Bacteroidetes ratio among Japanese female university students: A cross-sectional study.

Background & Aims: University students are prone to changes in their health status and lifestyle due to changes in their living environment and associated stress and anxiety. These changes may affect them in later life. This study utilized a cross-sectional study among Japanese female university students to examine dietary factors affecting their fecal microbiota. Methods: Sixty-eight healthy female university students were evaluated using an eating behavior assessment and diet history questionnaire. The 12-component Japanese diet index (JDI-12) was then calculated. A quantitative real-time PCR method was used to analyze the predominant bacterial species in the gut, and the Firmicutes/Bacteroidetes ratio (F/B ratio) at the phylum level was calculated. The partial correlation between the fecal microbiota and eating behavior abnormality score was assessed, and dietary habits associated with the F/B ratio were analyzed. Results: A significant correlation was identified between F/B ratios and the eating behavior abnormality score (r = 0.26, FDR = 0.064). Additionally, multiple regression analysis identified a negative correlation trend between the F/B ratio and JDI-12 score (ß = -0.22; p = 0.091), and exploratory analysis found a negative association between the F/B ratio and consumption of beef and pork, one of the less beneficial JDI-12 components (ß = -0.33, FDR = 0.120). Conclusion: In healthy female university students, there was a positive correlation between eating behavior abnormality and the F/B ratio, indicating that adherence to the Japanese diet pattern may be associated with a lower F/B ratio.

Effect of storage after heating on odor of muscles of yellowtail (Seriola quinqueradiata).

Effects of storage after heating on the odor of yellowtail Seriola quinqueradiata muscle were investigated. Sensory evaluation demonstrated odor degradation during storage of ordinary muscle as well as dark muscle (DM). First, different volatile profiles between OM (dorsal and ventral) and DM were found; their profiles were also different between non-stored samples (raw samples and just-heated samples) and stored samples except for a part of stored OM. Although the dorsal and ventral OMs differed in lipid content, their volatile profiles were similar to each other. The aforementioned differences were due to increased levels of lipid oxidation compounds (eg, aldehydes and alcohols) during storage after heating. However, none of the muscle parts showed significant changes in the intensity of each odor perceived by gas chromatography-olfactometry and trimethyl amine during storage. These findings suggested multiple volatile components may contribute to the odor deterioration of heated yellowtail muscle during cold storage.

Effect of different heating conditions on odor of yellowtail Seriola quinqueradiata muscles.

The effects of different heating conditions set to prevent food poisoning on the volatile components, lipid oxidation, and odor of yellowtail, Seriola quinqueradiata, were investigated. The heating conditions did not affect the lipid oxidation, fatty acid composition, and volatile compounds of each part of the flesh. High-temperature/short-time (90 °C for 6 min) heating led to significantly higher trimethylamine (TMA) contents in all muscle parts and higher odor intensity of TMA in dark muscle (DM) compared to those of lower temperature heating. Sensory evaluation showed that the odor intensities of all muscle parts heated at high-temperature/short-time were stronger than those at low-temperature/long-time (63 °C for 30 min). All DM samples had less odor palatability than the other flesh parts. Therefore, DM may have contributed to the unfavorable odor of steamed yellowtail meat and high-temperature/short-time heating may have enhanced the odor of all flesh parts compared with those subjected to low-temperature/long-time.

Analysis of Primary Metabolites in Cabbage (Brassica oleracea var. capitata) Varieties Correlated with Antioxidant Activity and Taste Attributes by Metabolic Profiling.

Brassica vegetables, such as cabbage, have many health benefits arising from their antioxidant and anticancer properties. These properties are endowed by the metabolite composition of the plant, and it is therefore important to elucidate the metabolic profile and associated activities in this genus. This study objectively evaluated the characteristics of cabbage varieties using metabolic profiling to identify the primary metabolic components that correlate with antioxidant activity and taste attributes. GC-MS analysis was used to identify the primary metabolites. Antioxidant activity was measured by oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging assays, and an electronic tongue was used to quantitate nine taste attributes. Orthogonal projections to latent structures (OPLS) using SIMCA 14 correlated the metabolite components with the taste and antioxidant characteristics. We identified 4-aminobutyric acid, fructose 1-phosphate, adipic acid, 5-oxoproline, N-acetylglycine, O-phosphoethanolamine, and homovanillic acid as important determinants of DPPH scavenging activity and umami, sourness, acidic bitterness, irritant and saltiness, bitterness, astringency, and richness, respectively. These metabolites represent markers indicating breed differences and contribute to differential cabbage functionality. These studies could be extended to measure additional metabolites, as well as to understand the role of growth conditions on the metabolic profile and health benefits of plants.

Changes in Metabolic Profiles of Yellowtail (Seriola quinqueradiata) Muscle during Cold Storage as a Freshness Evaluation Tool Based on GC-MS Metabolomics.

We applied metabolomics to the evaluation of yellowtail muscle as a new freshness evaluation method for fish meat. Metabolites from yellowtail ordinary and dark muscle (DM) stored at 0 °C and 5 °C were subjected to metabolomics for primary metabolites based on gas chromatography-mass spectrometry (GC-MS). For the annotated metabolites, we created statistically significant models for storage time prediction for all storage conditions by orthogonal partial least squares analysis, using storage time as the y-variable. DM is difficult to evaluate using the K value method, the predominant existing freshness evaluation method. However, in the proposed method, the metabolic component profiles of DM changed depending on storage time. Important metabolites determined from variables important for prediction (VIP) values included various metabolites, such as amino acids and sugars, in addition to nucleic-acid-related substances, especially inosine and hypoxanthine. Therefore, metabolomics, which comprehensively analyses different molecular species, has potential as a new freshness evaluation method that can objectively evaluate conditions of stored fish meat.

Taste Evaluation of Yellowtail (Seriola Quinqueradiata) Ordinary and Dark Muscle by Metabolic Profiling.

We performed metabolic profiling on yellowtail (Seriola quinqueradiata) muscle to develop an objective taste evaluation method for fish meat. Dark (DM) and ordinary (OM) muscle samples before and after storage were subjected to gas chromatography-mass spectrometry (GC-MS) analysis and taste measurements using an electronic tongue. The metabolites identified by the GC-MS analysis were treated as x variables, and the taste values obtained by the electronic tongue were treated as y variables. The relationships between the metabolites and taste attributes were evaluated by two-way orthogonal projections to latent structures (O2PLS) analysis. The O2PLS analyses were normalized in two ways, unit variance (UV) and pareto (Par) scaling. The O2PLS (UV) analysis produced 3+1+0 models in Autofit and this model was statistically significant with R2Y (0.73) and Q2 (0.52) metrics. In particular, significant correlations were found between DM or OM and metabolite intensity and taste attributes, and strong associations were found between "sourness" and lysine, "irritant" and alanine and phenylalanine, "saltiness" and pantothenic acid, and "umami" and creatinine and histidine. The O2PLS (Par) analysis of DM generated significant predictive models for "acidic bitterness," "irritant," "saltiness," "bitterness," "astringency," and "richness." Among these, only "irritant" was affected by storage. This method was thus effective in evaluating the taste of yellowtail muscle.

Metabolic Profiling of Fish Meat by GC-MS Analysis, and Correlations with Taste Attributes Obtained Using an Electronic Tongue.

To evaluate the taste of ordinary muscle from white-fleshed fish, we used GC-MS metabolomic analysis to characterise the compounds therein, and correlated the obtained data with taste measurements from an electronic tongue. Prediction models using orthogonal partial least squares were produced for different taste attributes, and the primary metabolic components correlated with the taste attributes were identified. Clear differences were observed in the component profiles for different fish species. Using an electronic tongue, differences in tastes were noted among the fish species in terms of sourness, acidic bitterness, umami and saltiness. The obtained correlations allowed the construction of good taste prediction models, especially for sourness, acidic bitterness and saltiness. Compounds such as phosphoric acid, lactic acid and creatinine were found to be highly correlated with some taste attributes. Phosphoric acid in particular showed the highest variable important for prediction (VIP) scores in many of the taste prediction models, and it is therefore a candidate marker to evaluate the tastes of white-fleshed fish.

Timing of post-resistance exercise nutrient ingestion: effects on gastric emptying and glucose and amino acid responses in humans.

This study examined the effects of post-resistance exercise protein ingestion timing on the rate of gastric emptying (GE) and blood glucose (BG) and plasma branched-chain amino acid (BCAA) responses. In all, eleven healthy participants randomly ingested 400 ml of a nutrient-rich drink containing 12 g carbohydrates and 20 g protein at rest (Con), at 5 min (post-exercise (PE)-5) or at 30 min (PE-30) after a single bout of strenuous resistance exercises. The first and second sets comprised ten repetitions at 50 % of each participant's one-repetition maximum (1RM). The third, fourth and fifth sets comprised ten repetitions at 75 % of 1RM, and the sixth set involved repeated repetitions until exhaustion. Following ingestion of the nutrient-rich drink, we assessed the GE rate using 13C-sodium acetate breath test and evaluated two parameters according to the T max-calc (time when the recovery per hour is maximised), which is a standard analytical method, and T 1/2 (time when the total cumulative dose of [13CO2] reaches one-half). T max-calc and T 1/2 were slower for the PE-5 condition than for either the PE-30 or Con condition (T max-calc; Con: 53 (sd 7) min, PE-5: 83 (sd 16) min, PE-30: 62 (sd 9) min, T 1/2; Con: 91 (sd 7) min, PE-5: 113 (sd 21) min, PE-30: 91 (sd 11) min, P<0·05). BG and BCAA responses were also slower for the PE-5 condition than for either the PE-30 or Con condition. Ingesting nutrients immediately after strenuous resistance exercise acutely delayed GE, which affected BG and plasma BCAA levels in blood circulation.

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). The assembled sequence of K7 was nearly identical to that of the S288C, except for several subtelomeric polymorphisms and two large inversions in K7. A survey of heterozygous bases between the homologous chromosomes revealed the presence of mosaic-like uneven distribution of heterozygosity in K7. The distribution patterns appeared to have resulted from repeated losses of heterozygosity in the ancestral lineage of K7. Analysis of genes revealed the presence of both K7-acquired and K7-lost genes, in addition to numerous others with segmentations and terminal discrepancies in comparison with those of S288C. The distribution of Ty element also largely differed in the two strains. Interestingly, two regions in chromosomes I and VII of S288C have apparently been replaced by Ty elements in K7. Sequence comparisons suggest that these gene conversions were caused by cDNA-mediated recombination of Ty elements. The present study advances our understanding of the functional and evolutionary genomics of the sake yeast.

Levels of glutathione and related enzymes in yellowtail fish muscle subjected to ice storage in a modified atmosphere.

UNLABELLED: We investigated the effects of ice storage in a modified atmosphere on levels of glutathione (GSH) and its related enzyme activities, the metmyoglobin to total myoglobin ratio (metMb%), and the K value (a freshness index) of yellowtail fish muscle. GSH in ordinary muscle (fast skeletal muscle) as well as in dark muscle (slow skeletal muscle) stored in air decreased. GSH in those muscles was almost unchanged during storage when packaged with an oxygen absorber or with an oxygen absorber-CO(2) generator. Glutathione disulfide in each type of packaging remained at low concentrations during storage. The GSH peroxidase activities of ordinary muscle and of dark muscle after 7 d of storage in air were lower than when packaged with the oxygen absorber or with the oxygen absorber-CO(2) generator. The GSH reductase (GR) activities of ordinary muscle at the 4th and 7th day of storage when packaged with the oxygen absorber showed a tendency to be lower than when stored in air. The GR activity of dark muscle in each type of packaging method was unchanged during storage. The packaging method did not influence the K values of either the ordinary muscle or the dark muscle during storage. The metMb% of dark muscle when packaged with the oxygen absorber was lower than in the other types of packaging during storage. Therefore, packaging with the oxygen absorber is an effective method to prevent the loss of GSH in fish meat as well as to reduce the discoloration during storage. PRACTICAL APPLICATION: This study examined whether modified atmosphere packaging preserves the level of GSH, which is unstable to oxidative stress, in fish muscle. The use of an oxygen absorber for packaging can allow us to take in a sufficient amount of the bioactive compound from fish meat after storage as well as fresh fish.

Enzyme inactivation and quality preservation of sake by high-pressure carbonation at a moderate temperature.

The effect of a high-pressure carbonation treatment on the change in quality of sake during storage was investigated. Measurements of the amino acidity and isovaleraldehyde content of carbonated sake (20 MPa pressure at 40, 45 and 50 degrees C for 7, 21 and 33 min, respectively) as well as of heat-treated sake (reaching temperature of 65 degrees C and immediately cooled) were almost unchanged during storage at 3 and 20 degrees C. Glucose in the sake subjected to these treatments was retained at an almost constant under the same storage conditions, except for the sake carbonated at 40 degrees C and stored at 20 degrees C. In contrast, the amino acidity, and glucose and isovaleraldehyde contents of non-pasteurized (fresh) sake increased during storage at both temperatures. The sake samples subjected to the carbonation treatment and heat treatment both gave better sensory scores than the fresh sake sample after 6 month of storage at 3 and 20 degrees C, especially at 3 degrees C for the flavor. These results suggest that the high-pressure carbonation treatment is an effective new technique for preserving the quality of sake.

Inactivation of enzymes in fresh sake using a continuous flow system for high-pressure carbonation.

The Inactivation kinetics of alpha-glucosidase, glucoamylase, alpha-amylase, and acid carboxypeptidase in fresh sake using a continuous flow system for high-pressure carbonation were investigated. In addition, the effects of ethanol and sugar concentrations on inactivation of the enzymes in high-pressure carbonated sake were investigated. Among the enzymes investigated, alpha-glucosidase was the most stable and alpha-amylase was the most labile on inactivation under carbonation. The decimal reduction times (D values) of alpha-glucosidase, glucoamylase, alpha-amylase (extrapolated from the Z value), and acid carboxypeptidase were 29, 6, 2, and 5 min respectively at 45 degrees C. These values are lower than those subjected to heat treatment. On the carbonation treatment as well as the heat treatment, ethanol accelerated the inactivation of all four enzymes, but glucose depressed the inactivation of these enzymes, except for acid carboxypeptidase. These results suggest that this continuous flow system enabled effective inactivation of enzymes in fresh sake.