Project description:Ultra-high performance liquid chromatography-quadrupole-time of flight tandem mass spectrometry (UHPLC-Q-TOF-MS/MS) was used to study the diversity of tea polysaccharides and the dynamic changes in the physicochemical indexes of tea samples. FT-IR spectra and the free radical scavenging ability of tea polysaccharides, during pile-fermentation of post-fermented tea, were analyzed. The results showed that 23 saccharide co mponents in tea polysaccharides were identified: these belonged to 11 monosaccharides, 5 oligosaccharides, and 6 derivatives of monosaccharides and oligosaccharides. The abundance of oligosaccharides decreased gradually, while monosaccharides, and derivatives of monosaccharides and oligosaccharides increased gradually with the development of pile-fermentation. According to the differences in polysaccharide composition and their abundance, the tea polysaccharide samples extracted from different pile-fermentation stages could be clearly classed into three groups, W-0, W-1~W-4 and W-5~C-1. The pile-fermentation process affected the yield, the content of each component, FT-IR spectra, and the DPPH free radical scavenging ability of tea polysaccharides. Correlation analysis showed that microorganisms were directly related to the changes in composition and the abundance of polysaccharides extracted from different pile-fermentation stages. The study will further help to reveal the function of tea polysaccharides and promote their practical application as a functional food.
Project description:Amino acids and biogenic amines are important components of food and beverages. In grape-derived products such as wine and wine vinegar, they can have different origins and can influence the odor and taste of the products. Their concentration is influenced by the grape variety, vintage, and winemaking process. In our study, we carried out an LC-MS-based comparative analysis of 22 grape-derived beverages, including three different wine types and four wine vinegar samples from the Tokaj region in Hungary. The concentrations of 23 amino acids and 10 biogenic amines were examined, and the differences among the sample types were analyzed. The differences in the concentrations of some metabolites between Aszú-Furmint pairs originating from the same wineries and year provide information on the effect of botrytized grape on wine composition. Our data can provide further evidence on how the production process shapes the metabolite content of beverages and highlight the nutritional value of wine vinegar.
Project description:Pea-tea intercropping is an excellent cultivation method that can improve tea quality. However, the underlying mechanism is still unclear. The present study was aimed at elucidating the mechanism of the effect of pea-tea intercropping on tea quality through a high-throughput method. Transcriptome and metabolome analyses were conducted to identify the changes in gene expression and metabolites changes intercropping, respectively. In addition, the amino acids and catechins were detected using the LC-MS method and quantified absolutely. The results showed that total polyphenols and catechins decreased but amino acids increased in pea intercropped tea shoots. Correspondingly, genes related to amino acid metabolism and flavonoid biosynthesis were differentially expressed. For amino acid metabolism, 11 differentially expressed genes were identified, including 5 upregulated and 6 downregulated genes. Meanwhile, three genes involved in carbohydrate transport and metabolism were upregulated in pea intercropped tea plants. These genes were also involved in amino acid metabolism. For flavonoid biosynthesis, two downregulated genes were identified, which were the flavonol synthase and anthocyanidin synthase genes and followed a similar pattern to changes in catechins and polyphenols. These advances have opened new horizons for understanding the biochemical mechanisms of amino acids and flavonoids in improving tea quality in the pea-tea intercropping cultivation model.
Project description:In order to study the differential expression of cold-tolerant variety SCZ and cold-sensitive variety YH9 during cold acclimation, we analyzed transcriptome and metabolome and found that the biosynthesis of amino acids may determine the difference of cold resistance of tea plant.
Project description:Plant albinism causes the etiolation of leaves because of factors such as deficiency of chloroplasts or chlorophylls. In general, albino tea leaves accumulate higher free amino acid (FAA) contents than do conventional green tea leaves. To explore the metabolic changes of etiolated leaves (EL) in the light-sensitive Japanese albino tea cultivar "Koganemidori," we performed integrated metabolome and transcriptome analyses by comparing EL with green leaves induced by bud-sport mutation (BM) or shading treatments (S-EL). Comparative omics analyses indicated that etiolation-induced molecular responses were independent of the light environment and were largely influenced by the etiolation itself. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and pathway analyses revealed the downregulation of genes involved in chloroplast development and chlorophyll biosynthesis and upregulation of protein degradation-related pathways, such as the ubiquitin-proteasome system and autophagy in EL. Metabolome analysis showed that most quantified FAAs in EL were highly accumulated compared with those in BM and S-EL. Genes involved in the tricarboxylic acid (TCA) cycle, nitrogen assimilation, and the urea cycle, including the drastically downregulated Arginase-1 homolog, which functions in nitrogen excretion for recycling, showed lower expression levels in EL. The high FAA contents in EL might result from the increased FAA pool and nitrogen source contributed by protein degradation, low N consumption, and stagnation of the urea cycle rather than through enhanced amino acid biosynthesis.
Project description:Protein intake reportedly increases the risk of diabetes; however, the results have been inconsistent. Diabetes in adulthood may be attributed to early life dietary amino acid composition. This study aimed to investigate the association between amino acid composition and glycemic biomarkers in adolescents. Dietary intake was assessed using a food frequency questionnaire, and fasting glucose and insulin levels were measured in 1238 eighth graders. The homeostatic model assessment (HOMA) indices (insulin resistance and β-cell function) were calculated. Anthropometrics were measured and other covariates were obtained from a questionnaire. Amino acid composition was isometric log transformed according to the compositional data analysis, which was used as explanatory variables in multivariate linear regression models for glucose, insulin, and HOMA indices. Only the association between glucose and leucine was significant. In replacement of other amino acids with leucine, an increase of 0.1% of total amino acids correlated with a lower glucose level (-1.02 mg/dL). One-to-one substitution of leucine for isoleucine or methionine decreased glucose (-2.98 and -2.28 mg/dL, respectively). Associations with other biomarkers were not observed. In conclusion, compositional data analysis of amino acids revealed an association only with glucose in adolescents; however, the results of this study should be verified in other populations.
Project description:Pichia manshurica is common in fermentation; however, genome analysis has never been reported for the species. This yeast plays a role in the secondary fermentation of Ishizuchi-kurocha, a traditional Japanese fermented tea. This paper presents the draft genome sequence of P. manshurica YM63, isolated from the leaves of fermented tea.
Project description:BackgroundThe levels of free amino acids (FAAs) and the timing of bud flush (TBF) are among the the most economic traits of tea plants (Camellia sinensis). Investigating the genetic variation characteristics of FAAs and their potential associations with TBF is critical for the breeding of new tea cultivars with high economic value.MethodsIn this study, we utilized the 'Emei Wenchun' (♀) × 'Chuanmu 217' (♂) filial 1 (F1) genetic population (n = 208) and measured their FAA contents in the "one bud and two leaves" samples across two spring seasons and one summer season using high-performance liquid chromatography combined with the Waters AccQ-Tag method. The sprouting index (SPI) was observed over two springs to quantify the TBF trait. A genetic map previously constructed based on the same population was employed for quantitative trait loci (QTL) mapping.ResultsA total of 16 FAAs were measured, and the average total FAA contents were 28.1 and 25.4 mg/g (dry weight) in the two spring seasons and 14.29 mg/g in the summer season. Within the population, the coefficients of variation (CV) for the FAAs ranged from 23 to 41% within each season, and the correlation coefficients (r) varied from 0.15 to 0.35 across seasons. ANOVA analyses revealed that 13 out of the 16 FAAs exhibited significant genetic variation, with the estimated broad-sense heritability (h2) ranging between 10.33% and 57.10%. Interestingly, three FAAs and the total FAA contents showed significant positive correlations (r = 0.21-0.34, P < 0.01) with the SPI trait in both spring seasons. QTL mapping identified 13 FAA-associated QTLs distributed across eight linkage groups.ConclusionWithin the F1 population, the FAAs exhibited considerable variation across seasons, their heritabilities were generally low (most ≤ 50%). There was a weak but significant positive correlation between FAAs and TBF. Additionally, 13 FAA-associated QTLs were identified. The results of this study enhance our understanding of the genetic variation characteristics of FAAs and provide insights for breeding tea cultivars with both higher FAAs and earlier TBF.
Project description:Screening for various types of lactic acid bacteria (LAB) that form the biological agent γ-amino-butyric acid (GABA) is important to produce different kinds of GABA-containing fermented foods. So far, no GABA-producing LAB have been reported from Cambodian fermented foods. Most small-scale fermentations and even some industrial processes in this country still rely on indigenous LAB. The application of GABA-producing autochthonous starters would allow the production of Cambodian fermented foods with an additional nutritional value that meet the population's dietary habits and that are also more attractive for the international food market. Matrix-assisted laser desorption/ionizing time-of-flight mass spectrometry (MALDI-TOF MS) and partial 16S rDNA sequencing were used to identify 68 LAB isolates from Cambodian fermented foods. These isolates were classified and grouped with (GTG)5 rep-PCR, resulting in 50 strains. Subsequently, all strains were investigated for their ability to produce GABA by thin layer chromatography. GABA-positive strains were further analyzed by the GABase assay. Of the six GABA-positive LAB strains-one Lactobacillus futsaii, two Lactobacillus namurensis, and three Lactobacillus plantarum strains-two Lactobacillus plantarum strains produced high amounts of GABA (20.34 mM, 16.47 mM). These strains should be further investigated for their potential application as GABA-producing starter cultures in the food applications.