1.Rectal Administration of Leek and Konjac-derived Extracellular Vesicles Alleviates High-fat Diet-induced Obesity in Mice via Gut Microbiota Modulation
Ya-Ru ZHANG ; Yu-Jia WU ; Cheng-Bang LIANG ; Xin-He YU ; Yan MU ; Yan TAN
Progress in Biochemistry and Biophysics 2026;53(5):1224-1239
ObjectiveObesity, a global chronic metabolic disease, is closely associated with disruptions in lipid metabolism and gut microbiota. Current intervention strategies still have limitations in terms of safety and microecological regulation, necessitating the exploration of novel natural regulatory approaches. Based on the early pathological characteristics of obesity, this study innovatively employs a rectal delivery method alongside a high-fat diet (HFD)-induced obesity model to systematically evaluate the inhibitory effects, safety, and gut microbiota regulation mechanisms of leek-derived and konjac-derived extracellular vesicles on obesity development. By simulating early clinical intervention scenarios, this study aims to explore the preventive potential of plant-derived extracellular vesicles during the initial stages of obesity onset. MethodsExtracellular vesicles from leek and konjac were isolated using ultracentrifugation combined with density gradient centrifugation. Their nanoscale properties were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA). Male C57BL/6J mice were randomly divided into four groups: normal control (NC), high-fat diet (HFD), leek-derived extracellular vesicles (LEVs), and konjac-derived extracellular vesicles (KEVs). Beginning simultaneously with HFD feeding, mice in the intervention groups received 20 g/L vesicles rectally every 3 d for 4 weeks. Body mass and body composition were monitored throughout. At endpoint, mouse serum, adipose tissue, and colonic contents were collected. Serum biochemical indices (lipid profile, liver and kidney function, cardiac markers) were assessed to evaluate safety and metabolic efficacy, while 16S rRNA sequencing was employed to analyze gut microbial structure and diversity. ResultsDLS, NTA, and TEM confirmed that both LEVs and KEVs exhibited typical cup-shaped nanostructures with average particle sizes of approximately 284 nm and 223 nm, respectively. LEVs and KEVs treatment significantly suppressed HFD-induced weight gain and elevation of body-fat percentage (P<0.05), and reduced accumulation of abdominal white and epididymal adipose tissue. Serological analyses showed that both vesicles lowered total cholesterol, triglycerides and LDL-cholesterol, and ameliorated liver enzyme profiles (ALT, AST), demonstrating lipid-metabolic regulation and hepatoprotective effects. No hepatic, renal or cardiac dysfunction was observed, indicating favorable safety. Gut microbiota analyses revealed that vesicle intervention partially restored HFD-depleted microbial diversity and reshaped community structure. Notably, LEVs markedly increased the relative abundance of the beneficial taxon Lachnospiraceae at the family level, which is known for producing short-chain fatty acids and enhancing intestinal barrier function. Furthermore, Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) functional prediction suggested that LEVs and KEVs modulated gut microbial functions through distinct mechanisms: LEVs downregulated pathways related to ribosomes and DNA replication while enhancing xenobiotic degradation, whereas KEVs tended to upregulate energy metabolism and protein synthesis toward healthy levels. ConclusionRectally administered LEVs and KEVs exhibit excellent safety and pronounced metabolic benefits during the early phase of obesity, suppressing weight gain, correcting lipid dysregulation, and exerting effects via modulation of gut microbial composition and function. This study provides systematic experimental evidence supporting plant-derived exosome-like vesicles as an early intervention strategy against obesity.
2.Rectal Administration of Leek and Konjac-derived Extracellular Vesicles Alleviates High-fat Diet-induced Obesity in Mice via Gut Microbiota Modulation
Ya-Ru ZHANG ; Yu-Jia WU ; Cheng-Bang LIANG ; Xin-He YU ; Yan MU ; Yan TAN
Progress in Biochemistry and Biophysics 2026;53(5):1224-1239
ObjectiveObesity, a global chronic metabolic disease, is closely associated with disruptions in lipid metabolism and gut microbiota. Current intervention strategies still have limitations in terms of safety and microecological regulation, necessitating the exploration of novel natural regulatory approaches. Based on the early pathological characteristics of obesity, this study innovatively employs a rectal delivery method alongside a high-fat diet (HFD)-induced obesity model to systematically evaluate the inhibitory effects, safety, and gut microbiota regulation mechanisms of leek-derived and konjac-derived extracellular vesicles on obesity development. By simulating early clinical intervention scenarios, this study aims to explore the preventive potential of plant-derived extracellular vesicles during the initial stages of obesity onset. MethodsExtracellular vesicles from leek and konjac were isolated using ultracentrifugation combined with density gradient centrifugation. Their nanoscale properties were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA). Male C57BL/6J mice were randomly divided into four groups: normal control (NC), high-fat diet (HFD), leek-derived extracellular vesicles (LEVs), and konjac-derived extracellular vesicles (KEVs). Beginning simultaneously with HFD feeding, mice in the intervention groups received 20 g/L vesicles rectally every 3 d for 4 weeks. Body mass and body composition were monitored throughout. At endpoint, mouse serum, adipose tissue, and colonic contents were collected. Serum biochemical indices (lipid profile, liver and kidney function, cardiac markers) were assessed to evaluate safety and metabolic efficacy, while 16S rRNA sequencing was employed to analyze gut microbial structure and diversity. ResultsDLS, NTA, and TEM confirmed that both LEVs and KEVs exhibited typical cup-shaped nanostructures with average particle sizes of approximately 284 nm and 223 nm, respectively. LEVs and KEVs treatment significantly suppressed HFD-induced weight gain and elevation of body-fat percentage (P<0.05), and reduced accumulation of abdominal white and epididymal adipose tissue. Serological analyses showed that both vesicles lowered total cholesterol, triglycerides and LDL-cholesterol, and ameliorated liver enzyme profiles (ALT, AST), demonstrating lipid-metabolic regulation and hepatoprotective effects. No hepatic, renal or cardiac dysfunction was observed, indicating favorable safety. Gut microbiota analyses revealed that vesicle intervention partially restored HFD-depleted microbial diversity and reshaped community structure. Notably, LEVs markedly increased the relative abundance of the beneficial taxon Lachnospiraceae at the family level, which is known for producing short-chain fatty acids and enhancing intestinal barrier function. Furthermore, Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) functional prediction suggested that LEVs and KEVs modulated gut microbial functions through distinct mechanisms: LEVs downregulated pathways related to ribosomes and DNA replication while enhancing xenobiotic degradation, whereas KEVs tended to upregulate energy metabolism and protein synthesis toward healthy levels. ConclusionRectally administered LEVs and KEVs exhibit excellent safety and pronounced metabolic benefits during the early phase of obesity, suppressing weight gain, correcting lipid dysregulation, and exerting effects via modulation of gut microbial composition and function. This study provides systematic experimental evidence supporting plant-derived exosome-like vesicles as an early intervention strategy against obesity.
3.Construction of Saccharomyces cerevisiae cell factory for efficient biosynthesis of ferruginol.
Mei-Ling JIANG ; Zhen-Jiang TIAN ; Hao TANG ; Xin-Qi SONG ; Jian WANG ; Ying MA ; Ping SU ; Guo-Wei JIA ; Ya-Ting HU ; Lu-Qi HUANG
China Journal of Chinese Materia Medica 2025;50(4):1031-1042
Diterpenoid ferruginol is a key intermediate in biosynthesis of active ingredients such as tanshinone and carnosic acid.However, the traditional process of obtaining ferruginol from plants is often cumbersome and inefficient. In recent years, the increasingly developing gene editing technology has been gradually applied to the heterologous production of natural products, but the production of ferruginol in microbe is still very low, which has become an obstacle to the efficient biosynthesis of downstream chemicals, such as tanshinone. In this study, miltiradiene was produced by integrating the shortened diterpene synthase fusion protein,and the key genes in the MVA pathway were overexpressed to improve the yield of miltiradiene. Under the shake flask fermentation condition, the yield of miltiradiene reached about(113. 12±17. 4)mg·L~(-1). Subsequently, this study integrated the ferruginol synthase Sm CYP76AH1 and Sm CPR1 to reconstruct the ferruginol pathway and thereby realized the heterologous synthesis of ferruginol in Saccharomyces cerevisiae. The study selected the best ferruginol synthase(Il CYP76AH46) from different plants and optimized the expression of pathway genes through redox partner engineering to increase the yield of ferruginol. By increasing the copy number of diterpene synthase, CYP450, and CPR, the yield of ferruginol reached(370. 39± 21. 65) mg·L~(-1) in the shake flask, which was increased by 21. 57-fold compared with that when the initial ferruginol strain JMLT05 was used. Finally, 1 083. 51 mg·L~(-1) ferruginol was obtained by fed-batch fermentation, which is the highest yield of ferruginol from biosynthesis so far. This study provides not only research ideas for other metabolic engineering but also a platform for the construction of cell factories for downstream products.
Saccharomyces cerevisiae/genetics*
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Diterpenes/metabolism*
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Metabolic Engineering
;
Fermentation
;
Abietanes
4.Medication rules and mechanisms of treating chronic renal failure by Jinling medical school based on data mining, network pharmacology, and experimental validation.
Jin-Long WANG ; Wei WU ; Yi-Gang WAN ; Qi-Jun FANG ; Yu WANG ; Ya-Jing LI ; Fee-Lan CHONG ; Sen-Lin MU ; Chu-Bo HUANG ; Huang HUANG
China Journal of Chinese Materia Medica 2025;50(6):1637-1649
This study aims to explore the medication rules and mechanisms of treating chronic renal failure(CRF) by Jinling medical school based on data mining, network pharmacology, and experimental validation systematically and deeply. Firstly, the study selected the papers published by the inherited clinicians in Jinling medical school in Chinese journals using the subject headings named "traditional Chinese medicine(TCM) + chronic renal failure", "TCM + chronic renal inefficiency", or "TCM + consumptive disease" in China National Knowledge Infrastructure, Wanfang, and VIP Chinese Science and Technology Periodical Database and screened TCM formulas for treating CRF according to inclusion and exclusion criteria. The study analyzed the frequency of use of single TCM and the four properties, five tastes, channel tropism, and efficacy of TCM used with high frequency and performed association rule and clustering analysis, respectively. As a result, a total of 215 TCM formulas and 235 different single TCM were screened, respectively. The TCM used with high frequency included Astragali Radix, Rhei Radix et Rhizoma, Salviae Miltiorrhizae Radix et Rhizoma, Poria, and Atractylodis Macrocephalae Rhizoma(top 5). The single TCM characterized by "cold properties, sweet flavor, and restoring spleen channel" and the TCM with the efficacy of tonifying deficiency had the highest frequency of use, respectively. Then, the TCM with the rules of "blood-activating and stasis-removing" and "diuretic and dampness-penetrating" appeared. In addition, the core combination of TCM [(Hexin Formula, HXF)] included "Astragali Radix, Rhei Radix et Rhizoma, Poria, Salviae Miltiorrhizae Radix, and Angelicae Sinensis Radix". The network pharmacology analysis showed that HXF had 91 active compounds and 250 corresponding protein targets including prostaglandin-endoperoxide synthase 2(PTGS2), PTGS1, sodium voltage-gated channel alpha subunit 5(SCN5A), cholinergic receptor muscarinic 1(CHRM1), and heat shock protein 90 alpha family class A member 1(HSP90AA1)(top 5). Gene Ontology(GO) function analysis revealed that the core targets of HXF predominantly affected biological processes, cellular components, and molecular functions such as positive regulation of transcription by ribonucleic acid polymerase Ⅱ and DNA template transcription, formation of cytosol, nucleus, and plasma membrane, and identical protein binding and enzyme binding. Kyoto Encyclopedia of Genes and Genomes(KEGG) analysis revealed that CRF-related genes were involved in a variety of signaling pathways and cellular metabolic pathways, primarily involving "phosphatidylinositol 3-kinase(PI3K)-protein kinase B(Akt) pathway" and "advanced glycation end products-receptor for advanced glycation end products". Molecular docking results showed that the active components in HXF such as isomucronulatol 7-O-glucoside, betulinic acid, sitosterol, and przewaquinone B might be crucial in the treatment of CRF. Finally, a modified rat model with renal failure induced by adenine was used, and the in vivo experimental confirmation was performed based on the above-mentioned predictions. The results verify that HXF can regulate mitochondrial autophagy in the kidneys and the PI3K-Akt-mammalian target of rapamycin(mTOR) signaling pathway activation at upstream, so as to alleviate renal tubulointerstitial fibrosis and then delay the progression of CRF.
Data Mining
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Drugs, Chinese Herbal/chemistry*
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Network Pharmacology
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Humans
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Kidney Failure, Chronic/metabolism*
;
Medicine, Chinese Traditional
;
China
5.Establishment of tissue culture and rapid propagation system of Artemisia stolonifera.
Chu WANG ; Ya XU ; Yang XU ; Ye WANG ; Na-Na CHANG ; Lu-Qi HUANG ; Hui LI
China Journal of Chinese Materia Medica 2025;50(11):2994-3000
As a high-quality moxibustion material, Artemisia stolonifera has high economic value and research prospects. However, due to difficulties in seed germination, its wild germplasm resources are sparsely distributed in China. This study used young stem segments grown in the current year to investigate the effects of explant sterilization, different combinations and concentrations of plant growth regulators on the proliferation and rooting of adventitious shoots, with the aim of constructing an in vitro rapid propagation technology system for A. stolonifera. The results showed that the lowest contamination rate of 25.83% was achieved when sterilizing the stem segments by rinsing with running water for 30 min, soaking in 75% ethanol for 30 s, followed by a 5 min treatment with 0.1% HgCl_2, 10 min with 8% NaClO, and 10 min with 0.6% phytosaniline. There was no browning of the stem segments, and surface sterilization of the A. stolonifera stem segments was successfully achieved. In the induction culture phase, when the concentration of kinetin(KT) was 0.05 mg·L~(-1) and 6-benzylaminopurine(6-BA) was 0.05 mg·L~(-1), the adventitious shoot proliferation coefficient was 2.02, effectively promoting the proliferation and growth of A. stolonifera. In the rooting culture phase, 0.1 mg·L~(-1) 1-naphthaleneacetic acid(NAA) effectively induced A. stolonifera test-tube seedlings to root within a short period, achieving a rooting rate of 100%. The addition of a small amount of activated charcoal also promoted rooting and strengthened seedling growth. The survival rate of A. stolonifera seedlings transplanted into a substrate consisting of 90% nutrient soil and 10% perlite was 100%. This study established an efficient in vitro rapid propagation system for A. stolonifera, overcoming difficulties with seed germination, shortening the breeding cycle, and reducing production and planting costs. It provides technical support for the introduction, domestication, seedling propagation, germplasm conservation, and industrial development of A. stolonifera.
Artemisia/drug effects*
;
Tissue Culture Techniques/methods*
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Plant Growth Regulators/pharmacology*
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Plant Stems/drug effects*
;
Plant Shoots/drug effects*
6.Association of Body Mass Index with All-Cause Mortality and Cause-Specific Mortality in Rural China: 10-Year Follow-up of a Population-Based Multicenter Prospective Study.
Juan Juan HUANG ; Yuan Zhi DI ; Ling Yu SHEN ; Jian Guo LIANG ; Jiang DU ; Xue Fang CAO ; Wei Tao DUAN ; Ai Wei HE ; Jun LIANG ; Li Mei ZHU ; Zi Sen LIU ; Fang LIU ; Shu Min YANG ; Zu Hui XU ; Cheng CHEN ; Bin ZHANG ; Jiao Xia YAN ; Yan Chun LIANG ; Rong LIU ; Tao ZHU ; Hong Zhi LI ; Fei SHEN ; Bo Xuan FENG ; Yi Jun HE ; Zi Han LI ; Ya Qi ZHAO ; Tong Lei GUO ; Li Qiong BAI ; Wei LU ; Qi JIN ; Lei GAO ; He Nan XIN
Biomedical and Environmental Sciences 2025;38(10):1179-1193
OBJECTIVE:
This study aimed to explore the association between body mass index (BMI) and mortality based on the 10-year population-based multicenter prospective study.
METHODS:
A general population-based multicenter prospective study was conducted at four sites in rural China between 2013 and 2023. Multivariate Cox proportional hazards models and restricted cubic spline analyses were used to assess the association between BMI and mortality. Stratified analyses were performed based on the individual characteristics of the participants.
RESULTS:
Overall, 19,107 participants with a sum of 163,095 person-years were included and 1,910 participants died. The underweight (< 18.5 kg/m 2) presented an increase in all-cause mortality (adjusted hazards ratio [ aHR] = 2.00, 95% confidence interval [ CI]: 1.66-2.41), while overweight (≥ 24.0 to < 28.0 kg/m 2) and obesity (≥ 28.0 kg/m 2) presented a decrease with an aHR of 0.61 (95% CI: 0.52-0.73) and 0.51 (95% CI: 0.37-0.70), respectively. Overweight ( aHR = 0.76, 95% CI: 0.67-0.86) and mild obesity ( aHR = 0.72, 95% CI: 0.59-0.87) had a positive impact on mortality in people older than 60 years. All-cause mortality decreased rapidly until reaching a BMI of 25.7 kg/m 2 ( aHR = 0.95, 95% CI: 0.92-0.98) and increased slightly above that value, indicating a U-shaped association. The beneficial impact of being overweight on mortality was robust in most subgroups and sensitivity analyses.
CONCLUSION
This study provides additional evidence that overweight and mild obesity may be inversely related to the risk of death in individuals older than 60 years. Therefore, it is essential to consider age differences when formulating health and weight management strategies.
Humans
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Body Mass Index
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China/epidemiology*
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Male
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Female
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Middle Aged
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Prospective Studies
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Rural Population/statistics & numerical data*
;
Aged
;
Follow-Up Studies
;
Adult
;
Mortality
;
Cause of Death
;
Obesity/mortality*
;
Overweight/mortality*
7.PM2.5 exposures exacerbate bleomycin-induced idiopathic pulmonary fibrosis in mice by regulating ferroptosis via Nrf2/SLC7A11/GPX4 axis
Jin-beng DING ; De-qi KONG ; Hui-min HUANG ; Yu GU ; Yue-bing CHEN ; Rui-li ZHAO ; Su-xiao LIU ; Xue-fang LIU ; Ya LI
Chinese Pharmacological Bulletin 2025;41(2):333-339
Aim To explore the mechanisms of PM2.5 exposure exacerbating bleomycin(BLM)-induced idio-pathic pulmonary fibrosis(IFP)by regulating ferropto-sis via nuclear factor 2 related factor 2(Nrf2)/solute carrier family 7 member 11(SLC7A11)/glutathione peroxidase(GPX)4 axis.Methods Forty C57BL/6J mice were randomized into the control,BLM,PM2.5,BLM+PM2.5 and sulforaphane(SFN,Nrf2 agonist)groups,with eight mice in each group.PM2.5 expo-sures were conducted to the BLM-induced IPF mice for two weeks.The lung function was measured,and the content of hydroxyproline(HYP)in lung tissue and the pathomorphology of lungs were observed.Reactive oxygen species(ROS),malondialdehyde(MDA),ferrous ion(Fe2+)and glutathione(GSH)of the lung tissue were measured by ELISA.The mRNA and pro-teins levels of Nrf2,SLC7A11,GPX4,collagen typeⅠ(COL-1),α-smooth muscle actin(α-SMA)were measured by quantitative polymerase chain reaction(qPCR)and Western blot.Results Compared with the control group,the lung function of mice was signif-icantly reduced(P<0.01)in the BLM and PM2.5 groups,while lung tissue showed the characteristic pathological changes of pulmonary fibrosis such as a large number of inflammatory cell infiltration,alveolar wall fracture,thickening,collagen deposition,and sig-nificantly increased HYP,Fe2+,ROS,MDA(P<0.05,P<0.01),genes and proteins of COL-1,α-SMA(P<0.01);and decreased GSH,Nrf2,SLC7A11,GPX4 genes and proteins(P<0.05,P<0.01).The above-mentioned lesions were markedly aggravated in the BLM+PM2.5 group compared with the BLM(P<0.05)and PM2.5 groups(P<0.01),and were also improved in the SFN group(P<0.05,P<0.01).Conclusions PM2.5 exposures can exac-erbate IPF-induced IPF in mice,and the regulating of Nrf2/SLC7 A1 1/GPX4 axis and ferroptosis might be in-volved in the related mechanisms.
8.Isolation,identification,and biological characterization of enterotoxigenic Escherichia coli from a South China tiger
Jing-ru XU ; Zhi-hao ZHU ; Yu-qi LI ; Si-si FAN ; Ya-li KANG ; Yu-bin ZHUO ; Ling-shan HUANG ; Shu-qi QIU ; XUE-YUXI ; Xiao-ping WU ; Yu-ting LIAO ; Wei-ye LIN ; Xiao-ziyi XIAO ; Xue-jin LI ; Teng-teng CHEN ; Xi-pan LIN ; Kai-xiong LIN ; Ke-wei FAN
Chinese Journal of Zoonoses 2025;41(6):567-573
This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.
9.Determination of Dilauryl Thiodipropionate in Fried Foods by Reverse Phase Liquid Chromatography-Tandem Mass Spectrometry
Jin-Can SHEN ; Yao LUO ; Feng-Qi WU ; Bei-Bei XIONG ; Zhang-Jie WU ; Ya-Mei LI ; Jun-Fa ZENG ; Chang-Xiong HUANG
Chinese Journal of Analytical Chemistry 2025;53(11):1860-1869
A method was developed for determination of dilauryl thiodipropionate(DLTDP)in fried foods by coupling solid-phase extraction(SPE)pretreatment with reverse-phase liquid chromatography-tandem mass spectrometry(RPLC-MS/MS)detection.Samples were extracted with n-hexane as the solvent,purified using a neutral alumina SPE cartridge,and finally analyzed by RPLC-MS/MS.Quantitative analysis was performed using matrix-matched calibration curves combined with an external standard method under optimal experimental conditions.The results showed that DLTDP exhibited good linearity in the range of 2.0-50.0 μg/L,with a correlation coefficient(R2)≥0.999.The limit of detection(LOD)and the limit of quantification(LOQ)of the method were 0.15 mg/kg and 0.5 mg/kg,respectively.The mean recoveries at three fortification levels(0.5,1.0,and 200 mg/kg)in different samples ranged from 84.8%to 96.8%,with the relative standard deviations(RSDs)all less than 8.0%.The developed method was highly sensitive,accurate and reliable,and easy to operate,making it well suited for the routine quantitative analysis of DLTDP in fried foods.
10.Isolation,identification,and biological characterization of enterotoxigenic Escherichia coli from a South China tiger
Jing-ru XU ; Zhi-hao ZHU ; Yu-qi LI ; Si-si FAN ; Ya-li KANG ; Yu-bin ZHUO ; Ling-shan HUANG ; Shu-qi QIU ; XUE-YUXI ; Xiao-ping WU ; Yu-ting LIAO ; Wei-ye LIN ; Xiao-ziyi XIAO ; Xue-jin LI ; Teng-teng CHEN ; Xi-pan LIN ; Kai-xiong LIN ; Ke-wei FAN
Chinese Journal of Zoonoses 2025;41(6):567-573
This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.

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