Metabonomics analysis of the flavor characteristics of Wuyi Rock Tea (Rougui) with "rock flavor" and microbial contributions to the flavor.

Wuyi Rock Tea (WRT) has different characteristics of "rock flavor" due to different production areas. In this study, we investigated the flavor characteristics and key components of "rock flavor" and the influence of microorganisms on the substances by combining metabolomics and microbiomics with the Rougui WRTs from the Zhengyan, Banyan, and Waishan production areas. The results showed that Rougui has a strong floral and fruity aroma, which is mainly brought by hotrienol, and the sweet, smooth, and fresh taste is composed of epicatechin gallate, epigallocatechin, epigallocatechin gallate, caffeine, theanine, soluble sugar, and sweet and bitter amino acids. Bacteria Chryseobacterium, Pedobacter, Bosea, Agrobacterium, Stenotrophomonas, and Actinoplanes mainly influence the production of hotrienol, epicatechin gallate, and theanine. Fungi Pestalotiopsis, Fusarium, Elsinoe, Teichospora and Tetracladium mainly influence the production of non-volatile compounds. This study provides a reference for the biological formation mechanism of the characteristic aroma of WRT's "rock falvor".

Metabolomics analysis of flavor differences in Shuixian (Camellia sinensis) tea from different production regions and their microbial associations.

Shuixian is renowned for its "rock flavor". However, the variations in Shuixian flavor are unclear, as the discussion mainly considers regional factors and overlooks the role of microorganisms. Sensory evaluation of Shuixian from three different regions (Zhengyan, Banyan, and Waishan) revealed that each had unique flavor characteristics: a woody aroma with slight acidity, a strong floral and fruity aroma with good freshness, and a distinct sweet aroma and sourness. Metabolomic analyses have revealed that 2-methylpyrazine was a crucial component of the woody aroma, whereas other metabolites contributed to sweet aroma, freshness, and acidity. Moreover, examinations of the relationship between flavor metabolites and microorganisms revealed that fungi had a more pronounced influence on the metabolite content of Shuixian. The study evaluated the role of fermentation microorganisms in shaping the flavor based on Shuixian flavor analyses, contributing to further research into the "rock flavor", as well as potential microbial interventions.

Effect of Thermophilic Microbial Agents on Crude Fiber Content, Carbohydrate-Active Enzyme Genes, and Microbial Communities during Chinese Medicine Residue Composting.

The objective of this study was to investigate the impact of thermophilic bacteria on crude fiber content, carbohydrate-active enzyme (CAZyme) genes, and associated microbial communities during Chinese medicine residues composting. The study examines changes over 15 days of composting with (T) and without (CK) thermophilic microbial agents. Results show that the group T compost temperature reached a maximum of 71.0 °C and remained above 70 °C for 2 days, while the group CK maximum temperature was only 60.9 °C. On Day 15, the seed germination index (GI) of group T reached 98.7%, while the group CK GI was only 56.7%. After composting, the degradation rates of cellulose, hemicellulose, and lignin in group T increased by 5.1, 22.5, and 18.5%, respectively, compared to those in group CK. Thermophilic microbial agents changed the microbial communities related to CAZymes, increasing unclassified_o_Myxococcales and Sphaerobacter abundance and reducing Acinetobacter and Sphingobacterium abundance. Thermophilic microbial agents also increased the abundance of the GT4, GT2_Glycos_transf_2, and AA3 gene families. These results show that thermophilic microbial agents can increase composting temperature, accelerate compost maturation, and promote crude fiber degradation. Therefore, they have broad application potential.

Metabolomics integrated with machine learning to discriminate the geographic origin of Rougui Wuyi rock tea.

The geographic origin of agri-food products contributes greatly to their quality and market value. Here, we developed a robust method combining metabolomics and machine learning (ML) to authenticate the geographic origin of Wuyi rock tea, a premium oolong tea. The volatiles of 333 tea samples (174 from the core region and 159 from the non-core region) were profiled using gas chromatography time-of-flight mass spectrometry and a series of ML algorithms were tested. Wuyi rock tea from the two regions featured distinct aroma profiles. Multilayer Perceptron achieved the best performance with an average accuracy of 92.7% on the training data using 176 volatile features. The model was benchmarked with two independent test sets, showing over 90% accuracy. Gradient Boosting algorithm yielded the best accuracy (89.6%) when using only 30 volatile features. The proposed methodology holds great promise for its broader applications in identifying the geographic origins of other valuable agri-food products.

Assessment of clinical, imaging, surgical risk factors for subsequent fracture following vertebral augmentation in osteoporotic patients.

INTRODUCTION: Currently, the risk factors for subsequent fracture following vertebral augmentation remain incomplete and controversial. To provide clinicians with accurate information for developing a preventive strategy, we carried out a comprehensive evaluation of previously controversial and unexplored risk factors. METHODS: We retrospectively reviewed patients with osteoporotic vertebral compression fracture in lumbar spine who received vertebral augmentation between January 2019 and December 2020. Based on whether refracture occurred, patients were assigned to refracture and non-refracture group. The clinical characteristics, imaging parameters (severity of vertebral compression, spinal sagittal alignment, degeneration of paraspinal muscles), and surgical indicators (cement distribution and leakage, correction of spinal sagittal alignment) were collected and analyzed. RESULTS: There were 128 patients and 16 patients in non-refracture and refracture group. The incidence of previous fracture, multiple fractures, and cement leakage were notably higher, relative cross-sectional area of psoas (r-CSAPS) was significantly smaller, CSA ratio, fatty infiltration of erector spinae plus multifidus (FIES+MF), FIPS, postoperative lumbar lordosis (post-LL), correction of body angel (BA), and LL were significantly greater in refracture group. Binary logistic regression analysis revealed previous fracture, cement leakage, post-LL, and correction of BA were independent risk factors. According to the ROC curve, correction of BA showed the highest prediction accuracy, and the critical value was 3.45°. CONCLUSIONS: The occurrence of subsequent fracture might be the consequence of multiple factors. Previous fracture, cement leakage, post-LL, and correction of BA were identified as independent risk factors. Furthermore, the correction of BA should not exceed 3.45°, especially in patients with risk factors.

Effect of thermophilic microbial agents on nitrogen transformation, nitrogen functional genes, and bacterial communities during bean dregs composting.

This study explored how a thermophilic microbial agent altered nitrogen transformation, nitrogen functional genes, and bacterial communities during bean dregs composting with (T) and without (CK) a thermophilic microbial agent for 15 days. The results showed that the maximum temperature in T reached 73 °C and remained above 70 °C for 8 days, while that in CK was only 65 °C. The pH in T had essentially stabilized on day 7, while that in CK was still increasing. On day 15, the seed germination index (GI) of T (95%) reached maturity (defined by GI ≥ 85%), while the GI of CK was only 36%. The concentrations of total nitrogen, water-soluble nitrogen, ammonia nitrogen, and nitrate nitrogen in T (2.5%, 18.9 g/kg, 8.75 g/kg, and 1.69 g/kg) were all lower than those in CK (3.6%, 28.9 g/kg, 12.75 g/kg, and 6.82 g/kg). During composting, Bacillus played a major role in nitrogen reduction, nitrogen mineralization, denitrification, and the conversion between nitrite and nitrate. Weissella played a major role in nitrogen assimilation. Komagataeibacter and Bacillus played a major role in nitrogen fixation in CK and T, respectively. Nitrification was not observed during composting. The nosZ gene, which converts nitrous oxide to nitrogen, was found only in T. Network analysis suggested that the average number of neighbours in T was 3.30% higher than that in CK and the characteristic path length in T was 14.15% higher than that in CK. Therefore, the thermophilic microbial agents could cause nitrogen loss but promote the maturity of bean dregs, which have great potential application.

Effect of Geobacillus toebii GT-02 addition on composition transformations and microbial community during thermophilic fermentation of bean dregs.

Bean dregs can be prepared into organic fertilizer by microbial fermentation. Geobacillus toebii GT-02, which has promoting effect on bean dregs fermentation, was isolated from horse dung and it grows within a range of 40-75 °C and pH 6.50-9.50. The effectiveness of GT-02 addition on composition transformations and the microbial community in bean dregs thermophilic fermentation at 70 °C for 5 days was investigated (T1). Fermentation of bean dregs without GT-02 served as control (CK). The results showed that T1 (the germination index (GI) = 95.06%) and CK (GI = 86.42%) reached maturity (defined by GI ≥ 85%) on day 3 and day 5, respectively. In addition, the total nitrogen loss of T1 (18.46%) on day 3 was lower than that in CK (24.12%). After thermophilic fermentation, the total organic carbon and dry matter loss of T1 (53.51% and 54.16%) was higher than that in CK (41.72% and 42.82%). The mean microbial number in T1 was 4.94 × 107 CFUs/g dry matter, which was 5.37 times higher than that in CK. 16S rDNA sequencing identified Bacillus, Geobacillus and Thermobacillus as dominant in CK, while Bacillus, Ammoniibacillus and Geobacillus were dominant in T1. A canonical correspondence analysis showed that Geobacillus and Ammoniibacillus were positively correlated with the GI. Thus, thermophilic fermentation with GT-02 can promote the maturity of bean dregs, which indicated the potential application value of GT-02 in thermophilic fermentation.