The State Tobacco Monopoly Administration (Chinese: 国家烟草专卖局) or China National Tobacco Corporation (commonly known as China Tobacco, CNTC) (Chinese: 中国烟草总公司; pinyin: Zhōngguó Yāncǎo Zǒnggōngsī) is a Chinese government agency responsible for tobacco regulation and a state-owned manufacturer of tobacco products, operated by the Ministry of Industry and Information Technology of China. It enjoys a virtual monopoly in China, which accounts for roughly 40% of the world's total consumption of cigarettes, and is the world's largest manufacturer of tobacco products measured by revenues. It exports a small proportion of its production, in majority to Asian markets.
The dynamic response and damage evolution of buried concrete pipelines in soft soil under traffic loads were investigated using finite element analysis and damage mechanics. A three-dimensional vehicle-pipe-soil coupled model was developed, incorporating a user-defined subroutine to simulate moving vehicle loads.Model reliability was validated against field tests, with the peak axial and hoop stresses showing relative errors of 2.7
Browning widely occurs during the processing of crops and their products, reducing both quality and economic value. However, the mechanisms underlying postharvest leaf browning under starvation-dominated conditions remain unclear. Here, compared with the standard curing practice (CK), lower tobacco leaves were subjected to a one-day dark treatment prior to curing to induce starvation-induced browning (SB), and were analyzed through integrated phenotypic characterization, enzyme activity assays, carbohydrate profiling, and widely targeted metabolomics during curing. The results showed that SB significantly intensified leaf browning and tissue shrinkage, accompanied by increased oxidative enzyme activities and malondialdehyde (MDA) content compared with CK during curing, as well as depletion of carbohydrate reserves, reflecting a pronounced metabolic imbalance. LC-MS/MS analysis identified a total of 812 metabolites in flue-cured tobacco leaves. Comparative analysis between CK and SB revealed 117 differentially accumulated metabolites (DAMs), including 73 up-regulated and 44 down-regulated metabolites. Notably, KEGG pathway analysis revealed extensive metabolic reprogramming, particularly involving in phenylpropanoid biosynthesis, flavone and flavonol biosynthesis pathways and phenylalanine, tyrosine and tryptophan biosynthesis pathways. It is worth emphasizing that SB treatment led to the accumulation of antioxidant-related metabolites (e.g., liquiritin and mangiferin) and the decrease in amino acids (e.g., phenylalanine, tryptophan and proline), highlighting the metabolic reprogramming underlying starvation-induced browning. Correlation analysis revealed significant correlations among metabolic changes, enzyme activities, browning severity, and water & structure traits. The results indicated that coordinated changes in enzymatic oxidation, substrate availability, and tissue water-structure properties are closely associated with postharvest leaf browning under starvation-dominated conditions, providing potential physiological and metabolic indicators for monitoring and mitigating browning in tobacco and other crops.
Bacterial wilt caused by Ralstonia solanacearum is a devastating soil-borne disease, calling for novel green control strategies. This study reports that the natural lipopeptide PW-1 controls this disease through an “anti-virulence” mechanism without inhibiting pathogen growth. Phenotypic analysis showed that PW-1 specifically impaired bacterial motility. Transcriptome sequencing revealed that PW-1 coordinately downregulated flagellar biosynthesis-related genes, and transmission electron microscopy confirmed the loss of flagellar filaments in PW-1-treated cells. Using GFP-tagged bacteria, we demonstrated that PW-1 significantly weakened early root colonization and systemic vascular invasion of the pathogen in tobacco. Correlation analysis of 107 field isolates indicated a strong positive relationship between motility and pathogenicity. Furthermore, a flhDC knockout mutant completely lost motility and exhibited drastically reduced virulence, genetically validating the essential role of flagella in pathogenicity. This work identifies PW-1 as a flagellum-targeting inhibitor that attenuates bacterial wilt by disrupting virulence, providing a theoretical basis and a lead compound for developing novel green pesticides targeting flagellar-mediated infection.
IntroductionTo investigate the impact of different processing methods on the volatile components in Aglaia odorata flower extract (AOFEs).MethodsHeadspace solid-phase microextraction coupled with gas chromatography-mass spectrometry and electronic nose (E-Nose) analysis were employed to characterize volatiles of extracts obtained by ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and heated reflux extraction (HRE). Multidimensional assessment using aroma radar charts, orthogonal partial least squares-discriminant analysis (OPLS-DA), K-means clustering, and relative odor activity value (ROAV) revealed significant processing-dependent variations.Results and discussionThe results indicated that the fiber coated with DVB/CAR/PDMS had optimal extraction efficiency. A total of 46 compounds were identified, including eight alcohols, four aldehydes, one acid, 25 terpenes, seven ketones, and one heterocyclic compound. UAE and MAE had 36 and 38 compounds respectively, sharing similar compositional profiles but differing in concentrations, while HRE produced only 25 compounds Sensory evaluation and E-Nose results revealed differences in the aroma profiles of the extracts, with UAE and MAE extracts exhibiting intensified floral and sweet notes, whereas HRE displayed prominent green and spicy characteristics. K-means clustering categorized volatile evolution trends into four distinct subclasses. OPLS-DA identified 13 differential volatiles with variable importance in projection greater than 1, with ROAV analysis further selecting eight key markers, including (1R,7S)-germacra-4(15),5,10(14)-trien-1β-ol, α-humulene, copaene, β-cadinene, (E)-β-caryophylene, Γ-cadinene, humulene oxide II, and caryophyllene oxide. These compounds collectively contribute to the sweet and floral attributes of AOFEs. This study elucidated extraction-method-dependent volatile profiles and aroma characteristics, providing theoretical guidance for process optimization and quality enhancement in AOFEs production.
