The mechanism of Laceyella sacchari FBKL4.010 produced tetramethylpyrazine in the liquid fermentation by comparative transcriptomic techniques.

Tetramethylpyrazine (TTMP) is considered a crucial flavor component in Moutai-flavored liquor. Laceyeella sacchari FBKL4.010 (L. sacchari) is the dominant species found in Moutai-flavor Daqu, and this study aims to determine the mechanism by which L. sacchari produces TTMP during liquid fermentation of Moutai-flavor Daqu. The results of the liquid fermentation performance demonstrated a gradual increase in biomass over time, while there was a gradual decline in residual glucose content and pH value. Furthermore, analysis of volatile components revealed that liquid fermentation significantly enhanced the production of TTMP in Moutai-flavor Daqu, with the relative content of TTMP reaching 14.24 mg/L after 96 h of liquid fermentation. Additionally, to explore the synthesis mechanism of TTMP, we compared differentially expressed genes (DEGs) of L. sacchari between 24 and 96 h using comparative transcriptomic techniques. The results indicated that DEGs involved in isoleucine, valine, and leucine biosynthesis pathway were upregulated, while those associated with isoleucine, valine, and leucine degradation pathway were downregulated, suggesting that the valine, leucine, and isoleucine biosynthesis pathway primarily contributes ammonia for TTMP synthesis. The findings of this study present an opportunity for further elucidating the production process of TTMP in Moutai-flavor Daqu during liquid fermentation.

Multiple bioinformatics analysis identifies IGFBP1 as associated with the prognosis of stomach adenocarcinoma.

This study aimed to screen the hub gene for predicting the prognosis of patients with stomach adenocarcinoma (STAD). The RNA-sequencing expression data and clinical data of STAD were collected from the cancer genome atlas. The R package "limma" was performed to ascertain the differentially expressed genes (DEGs) between the relapse group and non-relapse group, and the DEGs between the survival dead status group and survival alive status group were screened. The overlapping genes between 2 DEGs sets were identified by the Venn diagram. Many different bioinformatics analysis methods were performed to analyze the importance of hub genes. One gene signature, IGFBP1, was extracted. The KM plot indicated that STAD patients with low IGFBP1 mRNA expression have a shorter overall survival time. The top 100 co-expression genes of IGFBP1 were mainly enriched in complement and coagulation cascades, epithelial cell signaling in Helicobacter pylori infection, and Wnt signaling pathway. Immune infiltration analysis indicated IGFBP1 may inhibit immune cell infiltration in tumors by infiltration and immune escape, leading to tumor metastasis and progression. The bioinformatics analysis results indicate that IGFBP1 can be used as a tool to evaluate the mortality risk of patients with STAD.

Determining the changes in metabolites of Dendrobium officinale juice fermented with starter cultures containing Saccharomycopsis fibuligera FBKL2.8DCJS1 and Lactobacillus paracasei FBKL1.3028 through untargeted metabolomics.

BACKGROUND: The present study aimed to investigate the changes in volatile components and metabolites of Dendrobium officinale (D. officinale) juice fermented with starter cultures containing Saccharomycopsis fibuligera and Lactobacillus paracasei at 28 ℃ for 15 days and post-ripened at 4 ℃ for 30 days using untargeted metabolomics of liquid chromatography-mass spectrometry (LC-MS) and headspace solid-phase microextraction-gas chromatography (HS-SPME-GC-MS) before and after fermentation. RESULTS: The results showed that the alcohol contents in the S. fibuligera group before fermentation and after fermentation were 444.806 ± 10.310 µg/mL and 510.999 ± 38.431 µg/mL, respectively. Furthermore, the alcohol content in the fermentation broth group inoculated with the co-culture of L. paracasei + S. fibuligera was 504.758 ± 77.914 µg/mL, containing a significant amount of 3-Methyl-1-butanol, Linalool, Phenylethyl alcohol, and 2-Methyl-1-propanol. Moreover, the Ethyl L (-)-lactate content was higher in the co-culture of L. paracasei + S. fibuligera group (7.718 ± 6.668 µg/mL) than in the L. paracasei (2.798 ± 0.443 µg/mL) and S. fibuligera monoculture groups (0 µg/mL). The co-culture of L. paracasei + S. fibuligera significantly promoted the metabolic production of ethyl L (-)-lactate in D. officinale juice. The differential metabolites screened after fermentation mainly included alcohols, organic acids, amino acids, nucleic acids, and their derivatives. Twenty-three metabolites, including 11 types of acids, were significantly up-regulated in the ten key metabolic pathways of the co-culture group. Furthermore, the metabolic pathways, such as pentose and glucuronate interconversions, the biosynthesis of alkaloids derived from terpenoid and polyketide, and aminobenzoate degradation were significantly up-regulated in the co-culture group. These three metabolic pathways facilitate the synthesis of bioactive substances, such as terpenoids, polyketides, and phenols, and enrich the flavor composition of D. officinale juice. CONCLUSIONS: These results demonstrate that the co-culture of L. paracasei + S. fibuligera can promote the flavor harmonization of fermented products. Therefore, this study provides a theoretical basis for analyzing the flavor of D. officinale juice and the functional investigation of fermentation metabolites.