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Although the pathway and transcription factor regulation of anthocyanin biosynthesis in tea plants [Camellia sinensis (L.) O. Ktze] are known, post-transcriptional regulation mechanisms involved in anthocyanin accumulation have not been comprehensively studied. We obtained the full-length transcriptome of a purple cultivar (‘Zijuan’) and a normal green cultivar (‘Yunkang 10#) of C. sinensis var. asssamica (Masters) showing different accumulation of anthocyanins and catechins through PacBio isoform sequencing (Iso-Seq). In total, 577,557 mapped full-length cDNAs were obtained, and 2,600 average-length gene isoforms were identified in both cultivars. After gene annotations and pathway predictions, we found that 98 key genes in anthocyanin biosynthesis pathways could have undergone alternative splicing (AS) events, and identified a total of 238 isoforms involved in anthocyanin biosynthesis. We verified expression of the C4H, CHS, FLS, CCOM, F3′5’H, LAR, PAL, CCR, CYP73A13, UDP75L12, UDP78A15/UFGT, UDP94P1, GL3, MYB113, ANR, ANS, F3H, 4CL1, CYP98A3/C3H, CHI, DFR genes and their AS transcripts using qRT-PCR. Correlation analysis of anthocyanin biosynthesis and gene expression results revealed that C4H1, FLS1, PAL2, CCR2, UDP75L122 and MYB113-1 are crucial AS transcripts for regulating anthocyanin biosynthesis in C. sinensis var. assamica. Our results reveal post-transcriptional regulation of anthocyanin biosynthesis in tea plants, and provide more new insights into the regulation of secondary metabolism.

Tannase (E.C. 3.1.1.20) is hypothesized to be involved in the metabolism of gallates and gallic acid (GA) in pu-erh tea fermentation. In this work, we measured tannase in Aspergillus niger fermented tea leaves and confirmed the production of fungal tannase during pu-erh tea fermentation. A decrease in catechin and theaflavin gallates and a significant increase in GA content and the relative peak areas of ethyl gallate, procyanidin A2, procyanidin B2, procyanidin B3, catechin-catechin-catechin, epiafzelechin, and epicatechin-epiafzelechin [variable importance in the projection (VIP) > 1.0, p 1.5] were observed using high performance liquid chromatography (HPLC) and metabolomics analysis of tea leaves fermented or hydrolyzed by tannase. In vitro assays showed that hydrolysis by tannase or polymerization of catechins increased the antioxidant activity of tea leaves. In summary, we identified a metabolic pathway for gallates and their derivatives in tea leaves hydrolyzed by tannase as well as associated changes in gallate and GA concentrations caused by fungal tannase during pu-erh tea fermentation.

Tea is the second most widely consumed beverage and contains various bioactive compounds. A simple method to analyze these compounds is of great scientific and commercial interest. In this work, a 30 min HPLC method was developed using a simple gradient elution system, and the mobile phases and elution gradients were optimized. This method separated 17 polyphenols and three alkaloid compounds in tea extracts, including catechins, alkaloids, phenolic acids, flavonols, and flavone, which are responsible for the bioactivity and flavor of tea. Excellent linearity was observed for all standard calibration curves, and correlation coefficients were above 0.9994. Heatmap analysis demonstrated significant separation between green, black, and pu-erh tea samples. The method described here is accurate and sensitive enough for the determination of active components in tea and could potentially be applied to other food products for the comprehensive investigation of their quality.

One new Metal-Organic Frameworks, [Co4O(L)2]·(DMF)8·(H2O)8 (1, H3L = 4-[N,N-bis(4-methylbenzoic acid)amino]benzoic acid), had been successfully constructed under hydrothermal conditions, which firstly presents the [Co4O(COO)6] secondary-building unit similar to the typical [Zn4O(COO)6] one via single-crystal X-ray diffraction studies. All of the cobalt ions exhibit the four-coordinate environment, and possess more open metal sites. Heterogeneous catalytic experiments on allylic oxidation of cyclohexene indicate that 1 exhibits high catalytic activity by utilizing the tert-butylhydroperoxide (t-BuOOH) as the oxidant. The activation energy for the whole process of oxidation of cylcohexene had been calculated as 40.6 kJ mol−1, which indicate the important role of the special [Co4O(COO)6] cluster in the resulted heterogeneous catalyst.

Developing an effective method to improve the quality of Pu-erh tea is of great scientific and commercial interest. In this work, Penicillium chrysogenum P1 isolated from Pu-erh tea was inoculated in sterilized or unsterilized sun-dreid green tea leaves to develop pure-culture fermentation (PF) and enhanced fermentation (EF) of Pu-erh tea. Spectrophotometry and high performance liquid chromatography determined that contents of free amino acids (FAA), total tea polyphenols and eight polyphenolic compounds in PF were significantly lower than these in non-inoculation control test (CK) (P 0.05), whereas the contents of soluble sugars and theabrownins (TB) in PF were significantly higher (P 0.05) than in CK. A total of 416 volatile compounds were detected by headspace solid-phase micro-extraction combined with gas chromatography-mass spectrometry. Comparison to CK, 124 compounds in PF were degraded or decreased significantly [Variable importance in projection [(VIP) 1.0, P 0.05, fold change (FC) 0.5], whereas 110 compounds in PF were formed or increased significantly (VIP 1.0, P 0.05, FC 2). Compared with normal fermentation (NF), the levels of gallic acid, (+)-catechin, (-)-epicatechin and 64 volatile compounds in EF were significantly lower (VIP 1.0, P 0.05, FC 0.5), whereas the levels of FAA and 39 volatile compounds were significantly higher (VIP 1.0, P 0.05, FC 2). Amplicon sequencing of fungal internal transcribed spacer 1 (ITS1) revealed that P. chrysogenum P1 didn't become the dominant fungus in EF; while the fungal communities in EF were different from those in NF, in that the relative abundances of Blastobotrys bambusae and P. chrysogenum in EF were higher, and the relative abundances of Aspergillus niger and Kluyveromyces marxianus in EF were lower. Overall, inoculation of P. chrysogenum in unsterilized sun-dreid green tea leaves changed the the fungal communities in fermentation of Pu-erh tea, and chemical compounds in fermented tea leaves, i.e., the levels of TB and the compounds responsible for the stale flavor, e.g., 2-amino-4-methoxybenzothiazole were increased, resulting in improvement of the sensory quality, including mellower taste and stronger stale flavor.

Previously, we found that phospholipids derived from large yellow croaker (Pseudosciaena crocea) roe had a higher level of docosahexaenoic acid (DHA-PL), which had beneficial effects on lipid metabolism. However, the mechanism by which DHA-PL from P. crocea roe exerts these effects has not yet been illuminated. Herein, we investigated the underlying molecular action of DHA-PL by examining changes in liver protein expression in control, hyperlipidemic, and DHA-PL-treated mice. A total of 16 proteins, 9 up-regulated and 7 down-regulated, were identified and classified into several metabolic pathways, such as fat digestion and absorption, peroxisome proliferator activated receptor (PPAR) signaling, and antigen processing and presentation; the largest functional class found was that of fat digestion and absorption. We revealed Apoa1 to be a biomarker of DHA-PL effects on hyperlipidemic mice by DHA-PL diet. These results not only improve our current understanding of hyperlipidemic regulation by DHA-PL, but also suggest that DHA-PL should be applied as a beneficial food additive.

The aim of this study is to investigate the composition of the fatty acids and phospholipids derived from large yellow croaker (Pseudosciaena crocea) roe. The composition of the total lipids and the molecular species of phospholipids were determined by gas chromatography–mass spectroscopy (GC–MS) and high performance liquid chromatography–evaporative light scattering detector (HPLC–ELSD), respectively. The results showed that large yellow croaker roe had high levels of the total lipid (19.6% ± 1.32%, w/w) and phospholipid (61.2% ± 1.22% of the total lipid). The phospholipid was rich in docosahexaenoic acid (31.0% ± 0.19% of the total phospholipids), and the major phospholipid molecular species was phosphatidylcholine (PC, 61.06% ± 0.02% of the total phospholipids, w/w). It was concluded that large yellow croaker roe is expected to be a good resource of phospholipids with a high content of PC.

A simple and efficient RP high-performance liquid chromatography method was developed for simultaneous analysis of eight small antihypertensive peptides with tyrosine at the C-terminal in Laminaria japonica hydrolysates (LHs). The chromatography was performed on an Xterra MS-C18 column at 45C, with an aqueous mobile phase (0.1% trifluoroacetic acid, pH 2.8) acetonitrile in a linear gradient at the flow rate of 0.7 mL/min, and detected at 218 nm. The detection limits ranged from 0.0624 to 0.2365 μM. Correlation coefficients were greater than 0.9997. The recovery ranged from 92.17 to 120.08%. The small peptides were successfully determined by this method in LHs and the structures were confirmed by ESI-MS/MS, and the structure–activity relationships were discussed. The results demonstrated that the proposed method could be used to determine the peptides with tyrosine at the C-terminal, and to characterize a widespread detection mode for small peptide analysis in easy operation and low cost. Practical Applications This study is the first to report that marine Laminaria japonica protein hydrolyzed by combined enzymes of the alcalase, trypsin and papain displayed high angiotensin-converting enzyme (ACE) inhibitory activity. An effective and efficient reverse phase (RP) high-performance liquid chromatography method was developed for simultaneous analysis of eight small antihypertensive peptides with tyrosine at the C-terminal. Adopting the proposed method, Laminaria japonica hydrolysates and the ACE inhibitory activities of small peptides will be successfully analyzed. The results also demonstrated that Laminaria japonica proteins would be a good source of hypotensive peptides.

The difference of gene expression between sclerotia-producing and non-sclerotia-producing single spore isolates from Morchella conica were preliminary analyzed by mRNA differential display reverse transcription-polymerase chain reaction (RT-PCR) technique and 67 differential gene fragments were obtained. Fifty-eight of their second PCR products were cloned and sequenced. Thirteen special differential gene fragments related to sclerotial formation were validated by semi-quantitative RT-PCR. Some gene fragments had certain homologies with lipoprotein, cyclin-dependent kinase C-3, glycerophosphoryl diester phosphodiesterase, Rho GDP-dissociation inhibitor, gamma-aminobutyrate permease, OmpA family protein, Transcript antisense to ribosomal RNA protein, sodium–calcium exchange protein and keratin-associated proteins 5, 6. In addition, the putative protein of some DNA fragments had higher similarity with hypothetical protein-coding gene in NCBI database, as well as some were only putative gene fragments. All these fragments were speculated to be the functional gene associated with sclerotial formation in morel.