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According to the results of sensory evaluation performed by experts, 14 black tea samples were divided into two groups based on their aroma quality: high-quality and quality-deficient black tea. Using fast gas chromatography-electronic-nose (GC-E-Nose) and gas chromatography-mass spectrometry (GC-MS) combined with multivariate statistical analysis, discriminant analysis of the two groups were carried out, and the key differential components between these groups were selected. The results showed that 117-dimensional dataset was obtained by the fusion of the GC-E-Nose (44-dimensional) and GC-MS (73-dimensional) data and used to establish a model for accurate classification of the two types of black tea employing orthogonal partial least squares-discriminant analysis (OPLS-DA). The model’s explanatory and predictive capacity (R2Y = 0.976, Q2 = 0.959) were better than those of the model established based on the GC-E-Nose or GC-MS data. Based on variable important in projection (VIP) scores > 1.6 and P < 0.05, eight key aroma components including dimethyl sulfide (B3 and B25), β-ionone (A59), (3E)-4,8-dimethylnon-1,3,7-triene (A20), dihydroactinidiolide (A64), linalool (A17), phenylethyl alcohol (A19), δ-octyl lactone (A41) and γ-nonalatone (A45) were selected, which played an important role in the classification. These results showed that GC-E-Nose combined with GC-MS allows rapid and accurate discrimination between quality-deficient and high-quality black tea, which can be used as a supplement to traditional sensory evaluation, providing technical support for quality control and improvement of black tea.

This research was undertaken to explore the effects of different rolling speeds (35, 45, 55 and 60 r/min) on the flavor quality and internal quality components of Congou black tea from the Jiukeng cultivar. Flavor attributes including taste and color were determined by sensory evaluation, color difference analysis and electronic tongue analysis. Quantitative analysis of tea pigments and theaflavin components were performed by systematic analysis and high-performance liquid chromatography (HPLC). In addition, metabolomics based on ultra-high performance liquid chromatography-quadrupole orbitrap high resolution-mass spectrometry (UPLC-Q-Orbitrap-MS) was used to determine the non-volatile compounds in Congou black tea. Partial least squares discriminant analysis (PLS-DA) and one-way analysis of variance (ANOVA) were used to investigate the effect of different rolling speeds on the internal quality components of Congou black tea. The results showed that a rolling speed of 45 r/min resulted in the best sensory quality of Congou black tea, especially in taste and aroma, as verified by color difference and electronic tongue analysis. Sixteen significantly differential metabolites were identified among the four tea samples, including procyanidin C1, vitexin, isovitexin, asparagine, aspartic acid, gallic acid, malic acid, succinic acid, and gluconic acid. It was found that rolling speed showed a significant influence on phenolic acids, organic acids and tea pigments (theaflavins, thearubigins, and theabrownins), but had little effect on other metabolites. The contents of thearubigins, carbohydrates and aspartic acid and quality index were highest in Congou black prepared with a rolling speed of 45 r/min, and the contents of organic acids, phenolic acids and theabrownins were lowest, which indicated that this rolling speed was more favorable for the formation of the flavor quality of Congou black tea. This study is expected to provide a theoretical basis and technical guidance for the improvement of Congou black tea quality and the precise production of Congou black tea.

The taste of tea infusions is one of the important factors to evaluate the quality and classify the grade of tea. In order to explore the key components that cause the difference in different grades of Dianhong tea infusions, this study systematically studied the taste quality of different grades of Dianhong tea infusions by combining sensory evaluation, electronic tongue and ultra -performance liquid chromatography -quadrupole orbital trap mass spectrometry. The results showed that the taste attributes of 12 Dianhong infusions were divided into three groups (superior-quality group, good-quality group and poor-quality group) according to the sensory evaluation. The results of electronic tongue were consistent with the sensory evaluation. The response of electronic tongue sensors corresponding to different taste properties to the three groups of tea infusion was different. Further, the metabolomics were studied by ultra-performance liquid chromatog-raphy-quadrupole orbital trap mass spectrometry. A total of 116 compounds were detected, including 26 amino acids and their derivatives, 15 catechins and their polymers, 16 phenolic acids, 15 nucleotides and their derivatives, 20 flavonoids (alcohols) and their glycosides, 6 alkaloids, 11 organic acids, 2 sugars and 5 other classes. In addition, three groups of Dianhong tea infusions were well distinguished by using orthogonal partial least squares regression analysis (R2Y =0.985, #2=0.902). In addition, based on VIP>1.2 and significance P<0.05, a total of 7 key differential components affecting different grades of tea infusions were screened out, specifically, arginine, gallatechin, epicatechin, uric acid, abscisic acid, niacin, adenosine-5 '-diphosphate. The results provided theoretical support for quality evaluation and quality control of different grades of Dianhong tea infusions. [ABSTRACT FROM AUTHOR]

Objective This study detects the expression of secreted frizzled-related protein 1 (SFRP1) in healthy patients and patients with chronic periodontitis (CP) and explores the relationship between SFRP1 and the occurrence and development of CP. Methods First, 28 patients forming the CP group were further divided into mild, moderate, and severe CP subgroups according to clinical attachment loss (CAL) data. Ten healthy volunteers were recruited in the control group. Gingival crevi-cular fluid (GCF) was collected from all of the patients, and the concentration of SFRP1 in the GCF samples was detected using enzyme-linked immunosorbent assay. Next, gingival lesions were obtained from 22 patients in the CP group and healthy gingival tissues were obtained from the 10 healthy patients in the control group. Immunohistochemical analysis for SFRP1 was used to analyze the correlation between the expression of SFRP 1 and the severity of CP based on staining intensities. Results The concentration of SFRP1 in GCF samples taken from of the CP group (281.07 ng-L-1±33.37 ng-L-1) was significantly higher than that in samples taken from the control group (245.30 ng-L-1±35.69 ng-L-1) (P<0.05). A significant positive correlation was observed between the concentration of SFRP1 in GCF and CAL (r=0.651,P<0.001). Furthermore, the SFRP1 scores in the CP groups (4.500±0.913) were significantly higher than those in the control group (2.800±1.135) (P<0.001). SFRP1 scores did not vary significantly among the CP subgroups (P>0.05). Conclusion SFRP1 expression in the CP groups was significantly higher than that in the control group. Thus, SFRP1 may play a significant role in the development of CP. [ABSTRACT FROM AUTHOR]

Objective: To construct a cell model of gsdmd gene knockout in macrophage RAW 264.7 cells using CRISPR/Cas9 system., Methods: Four specific single guide RNAs (sgRNAs) targeting gsdmd were designed to construct pGL3-sgRNA recombinant plasmids, which were identified by PCR amplification and sequencing.Cas9 and the recombinant plasmids were transfected into RAW 264.7 cells in two steps, and the cellular expression of cas9 was detected with real-time quantitative PCR (qPCR).The positive cell clones with gsdmd gene knockout were screened using puromycin and verified by sequencing and Western blotting.Annexin Ⅴ/PI staining and LDH release assay were performed in gsdmd -/-RAW 264.7 cells after being co-cultured with Salmonella Typhimurium ., Results: qPCR results showed that cas9 gene was stably expressed in RAW 264.7-Cas9 cells ( P < 0.01).PCR and sequencing results demonstrated successful construction of the recombinant plasmid pGL3-sgRNA. The results of PCR, sequencing and Western blotting all confirmed that gsdmd -/- RAW 264.7 cells were successfully constructed. Annexin Ⅴ/PI staining and LDH release assay showed that gsdmd gene knockout significantly inhibited macrophage death caused by S.Typhimurium infection ( P < 0.01)., Conclusions: gsdmd -/- RAW 264.7 cells provide a cell model for studying the mechanisms underlying GSDMD-mediated macrophage death.

Objective: This study detects the expression of secreted frizzled-related protein 1 (SFRP1) in healthy patients and patients with chronic periodontitis (CP) and explores the relationship between SFRP1 and the occurrence and development of CP., Methods: First, 28 patients forming the CP group were further divided into mild, moderate, and severe CP subgroups according to clinical attachment loss (CAL) data. Ten healthy volunteers were recruited in the control group. Gingival crevicular fluid (GCF) was collected from all of the patients, and the concentration of SFRP1 in the GCF samples was detected using enzyme-linked immunosorbent assay. Next, gingival lesions were obtained from 22 patients in the CP group and healthy gingival tissues were obtained from the 10 healthy patients in the control group. Immunohistochemical analysis for SFRP1 was used to analyze the correlation between the expression of SFRP1 and the severity of CP based on staining intensities., Results: The concentration of SFRP1 in GCF samples taken from of the CP group (281.07 ng x L(-1) +/- 33.37 ng x L(-1)) was significantly higher than that in samples taken from the control group (245.30 ng x L(-1) +/- 35.69 ng x L(-1)) (P < 0.05). A significant positive correlation was observed between the concentration of SFRP1 in GCF and CAL (r = 0.651, P < 0.001). Furthermore, the SFRP1 scores in the CP groups (4.500 +/- 0.913) were significantly higher than those in the control group (2.800 +/- 1.135) (P < 0.001). SFRP1 scores did not vary significantly among the CP subgroups (P > 0.05)., Conclusion: SFRP1 expression in the CP groups was significantly higher than that in the control group. Thus, SFRP1 may play a significant role in the development of CP.