1.The regulation and mechanism of apolipoprotein A5 on myocardial lipid deposition.
Xiao-Jie YANG ; Jiang LI ; Jing-Yuan CHEN ; Teng-Teng ZHU ; Yu-Si CHEN ; Hai-Hua QIU ; Wen-Jie CHEN ; Xiao-Qin LUO ; Jun LUO
Acta Physiologica Sinica 2025;77(1):35-46
The current study aimed to clarify the roles of apolipoprotein A5 (ApoA5) and milk fat globule-epidermal growth factor 8 (Mfge8) in regulating myocardial lipid deposition and the regulatory relationship between them. The serum levels of ApoA5 and Mfge8 in obese and healthy people were compared, and the obesity mouse model induced by the high-fat diet (HFD) was established. In addition, primary cardiomyocytes were purified and identified from the hearts of suckling mice. The 0.8 mmol/L sodium palmitate treatment was used to establish the lipid deposition cardiomyocyte model in vitro. ApoA5-overexpressing adenovirus was used to observe its effects on cardiac function and lipids. The expressions of the fatty acid uptake-related molecules and Mfge8 on transcription or translation levels were detected. Co-immunoprecipitation was used to verify the interaction between ApoA5 and Mfge8 proteins. Immunofluorescence was used to observe the co-localization of Mfge8 protein with ApoA5 or lysosome-associated membrane protein 2 (LAMP2). Recombinant rMfge8 was added to cardiomyocytes to investigate the regulatory mechanism of ApoA5 on Mfge8. The results showed that participants in the simple obesity group had a significant decrease in serum ApoA5 levels (P < 0.05) and a significant increase in Mfge8 levels (P < 0.05) in comparison with the healthy control group. The adenovirus treatment successfully overexpressed ApoA5 in HFD-fed obese mice and palmitic acid-induced lipid deposition cardiomyocytes, respectively. ApoA5 reduced the weight of HFD-fed obese mice (P < 0.05), shortened left ventricular isovolumic relaxation time (IVRT), increased left ventricular ejection fraction (LVEF), and significantly reduced plasma levels of triglycerides (TG) and cholesterol (CHOL) (P < 0.05). In myocardial tissue and cardiomyocytes, the overexpression of ApoA5 significantly reduced the deposition of TG (P < 0.05), transcription of fatty acid translocase (FAT/CD36) (P < 0.05), fatty acid-binding protein (FABP) (P < 0.05), and fatty acid transport protein (FATP) (P < 0.05), and protein expression of Mfge8 (P < 0.05), while the transcription levels of Mfge8 were not significantly altered (P > 0.05). In vitro, the Mfge8 protein was captured using ApoA5 as bait protein, indicating a direct interaction between them. Overexpression of ApoA5 led to an increase in co-localization of Mfge8 with ApoA5 or LAMP2 in cardiomyocytes under lipid deposition status. On this basis, exogenous added recombinant rMfge8 counteracted the improvement of lipid deposition in cardiomyocytes by ApoA5. The above results indicate that the overexpression of ApoA5 can reduce fatty acid uptake in myocardial cells under lipid deposition status by regulating the content and cellular localization of Mfge8 protein, thereby significantly reducing myocardial lipid deposition and improving cardiac diastolic and systolic function.
Animals
;
Humans
;
Mice
;
Myocytes, Cardiac/metabolism*
;
Obesity/physiopathology*
;
Male
;
Apolipoprotein A-V/blood*
;
Lipid Metabolism/physiology*
;
Milk Proteins/blood*
;
Myocardium/metabolism*
;
Diet, High-Fat
;
Antigens, Surface/physiology*
;
Mice, Inbred C57BL
;
Cells, Cultured
;
Female
2.Mechanism of icariin in promoting osteogenic differentiation of BMSCs and improving bone metabolism disorders through caveolin-1/Hippo signaling pathway.
Yi-Dan HAN ; Hai-Feng ZHANG ; Yun-Teng XU ; Yu-Huan ZHONG ; Xiao-Ning WANG ; Yun YU ; Yuan-Li YAN ; Shan-Shan WANG ; Xi-Hai LI
China Journal of Chinese Materia Medica 2025;50(3):600-608
Guided by the theory of "the kidney storing essence, governing the bones, and producing marrow", this study explored the mechanism of icariin(ICA) in regulating the osteogenic differentiation of rat bone mesenchymal stem cells(BMSCs) through caveolin-1(Cav1) via in vitro and in vivo experiments, aiming to provide a theoretical basis for the prevention and treatment of postmenopausal osteoporosis with traditional Chinese medicine(TCM). Primary cells were obtained from 4-week-old female SD rats using the whole bone marrow adherent method. Flow cytometry was used to detect the expression of surface markers CD29, CD90, CD11b, and CD45. The potential for osteogenic and adipogenic differentiation was assessed. The effect of ICA on cell viability was determined using the CCK-8 assay, and the impact of ICA on the formation of mineralized nodules was verified by alizarin red staining. A stable Cav1-silenced cell line was constructed using lentivirus. The effect of Cav1 silencing on osteogenic differentiation was observed via alizarin red staining. Western blot analysis was conducted to detect the expression of Cav1, Hippo/TAZ, and osteogenic markers such as Runt-related transcription factor 2(RUNX2) and alkaline phosphatase(ALP). The results showed that primary cells were successfully obtained using the whole bone marrow adherent method, positively expressing surface markers of rat BMSCs and possessing the potential for both osteogenic and adipogenic differentiation. The CCK-8 assay and alizarin red staining results indicated that 1×10~(-7) mol·L~(-1) was the optimal concentration of ICA for intervention in this experiment(P<0.05). During osteogenic induction, ICA inhibited Cav1 expression(P<0.05) while promoting TAZ expression(P<0.05). Alizarin red staining demonstrated that Cav1 silencing significantly promoted the osteogenic differentiation of BMSCs. After ICA intervention, TAZ expression was activated, and the expression of osteogenic markers ALP and RUNX2 was increased. In conclusion, Cav1 silencing significantly promotes the osteogenic differentiation of BMSCs, and ICA promotes this differentiation by inhibiting Cav1 and regulating the Hippo/TAZ signaling pathway.
Animals
;
Mesenchymal Stem Cells/metabolism*
;
Caveolin 1/genetics*
;
Osteogenesis/drug effects*
;
Rats, Sprague-Dawley
;
Rats
;
Cell Differentiation/drug effects*
;
Female
;
Signal Transduction/drug effects*
;
Flavonoids/administration & dosage*
;
Protein Serine-Threonine Kinases/genetics*
;
Drugs, Chinese Herbal/pharmacology*
;
Cells, Cultured
;
Humans
3.Huotan Jiedu Tongluo Decoction inhibits ferroptosis by regulating Nrf2/GPX4 pathway to ameliorate atherosclerotic lesions in ApoE~(-/-) mice.
Di GAO ; Teng-Hui TIAN ; Ke-Ying YU ; Xiao SHAO ; Wen XUE ; Zhi-Xuan ZHAO ; Yue DENG
China Journal of Chinese Materia Medica 2025;50(7):1908-1919
The purpose of this study was to clarify the effect of Huotan Jiedu Tongluo Decoction on atherosclerosis(AS) injury in ApoE~(-/-) mice by regulating the ferroptosis pathway. Seventy-five ApoE~(-/-) mice were randomly divided into model group, low-, medium-, and high-dose of Huotan Jiedu Tongluo Decoction groups, and evolocumab group(n=15), and 15 C57BL/6J mice were selected as the blank group. Mice in the blank group were fed with a normal diet, and those in the other groups were fed with a high-fat diet to induce AS. From the 9th week, mice in Huotan Jiedu Tongluo Decoction groups were administrated with Huotan Jiedu Tongluo Decoction at corresponding doses by gavage, and those in the blank group and the model group were given an equal volume of distilled water. Mice in the evolocumab group were treated with evolocumab 18.2 mg·kg~(-1 )by subcutaneous injection every 2 weeks. After 8 weeks of continuous intervention, oil red O staining and hematoxylin-eosin(HE) staining were employed to observe the lipid deposition and plaque formation in the aortic root. Masson staining was used to evaluate the collagen content in the aortic root. The serum levels of total cholesterol(TC), triglycerides(TG), high-density lipoprotein cholesterol(HDL-C), and low-density lipoprotein cholesterol(LDL-C) were determined by biochemical kits. The levels of Fe~(2+), superoxide dismutase(SOD), malondialdehyde(MDA), and glutathione(GSH) in the aorta were measured by colorimetry. The protein and mRNA levels of nuclear factor erythroid 2-related factor 2(Nrf2), glutathione peroxidase 4(GPX4), solute carrier family 7 member 11(SLC7A11), and acyl-CoA synthetase long chain family member 4(ACSL4) in the aorta were detected by Western blot and RT-qPCR, respectively. The expression of Nrf2, GPX4, and SLC7A11 was localized by immunofluorescence. The results showed that low-, medium-, and high-dose Huotan Jiedu Tongluo Decoction reduced the plaque formation of aortic root and increased the collagen content in AS mice. At the same time, Huotan Jiedu Tongluo Decoction improved the lipid metabolism by lowering the levels of TC, LDL-C, and TG and elevating the level of HDL-C in the serum. Huotan Jiedu Tongluo Decoction enhanced the antioxidant capacity by elevating the levels of GSH and SOD and lowering the level of MDA in the aorta and inhibiting the accumulation of Fe~(2+) in the aorta. In addition, Huotan Jiedu Tongluo Decoction up-regulated the protein and mRNA levels of Nrf2, GPX4, and SLC7A11, while down-regulating the protein and mRNA levels of ACSL4. In summary, Huotan Jiedu Tongluo Decoction can effectively alleviate AS lesions in ApoE~(-/-) mice by activating the Nrf2/GPX4 pathway, reducing lipid peroxidation, and inhibiting ferroptosis.
Animals
;
Ferroptosis/drug effects*
;
Atherosclerosis/metabolism*
;
Drugs, Chinese Herbal/administration & dosage*
;
NF-E2-Related Factor 2/genetics*
;
Mice
;
Mice, Inbred C57BL
;
Apolipoproteins E/metabolism*
;
Male
;
Phospholipid Hydroperoxide Glutathione Peroxidase/genetics*
;
Signal Transduction/drug effects*
;
Humans
;
Mice, Knockout
4.Clinical Applications of Circulating Tumor DNA in Response Evaluation and Relapse Monitoring of Primary Mediastinal Large B-Cell Lymphoma.
Lu PAN ; Xin-Miao JIANG ; Yan TENG ; Ning WANG ; Ling HUANG ; Han-Guo GUO ; Si-Chu LIU ; Xiao-Juan WEI ; Fei-Li CHEN ; Zhan-Li LIANG ; Wen-Yu LI
Journal of Experimental Hematology 2025;33(2):407-415
OBJECTIVE:
To explore the clinical significance of circulating tumor DNA (ctDNA) in response evaluation and relapse monitoring for patients with primary mediastinal large B-cell lymphoma (PMBCL).
METHODS:
The clinical characteristics, efficacy and survival of 38 PMBCL patients in our hospital from January 2010 to April 2020 were retrospectively analyzed. The ctDNA monitoring was conducted by targeted next-generation sequencing (NGS).
RESULTS:
Among the 38 patients, 26 cases were female, and 32 cases were diagnosed with Ann Arbor stage I-II. The 5-year overall survival (OS) rate and progression-free survival (PFS) rate were 74.7% and 61.7%, respectively. Males and those with high aaIPI scores (3 points) had a relatively poor prognosis. The NGS results of 23 patients showed that STAT6 (65.2%), SOCS1 (56.5%), and TNFAIP3 (56.5%) were the most common mutated genes. Patients with stable disease (SD)/progressive disease (PD) exhibited enrichment in cell cycle, FoxO, and TNF signaling pathways. A total of 29 patients underwent end-of-treatment PET/CT (EOT PET/CT), and 16 of them received ctDNA monitoring with 12 negative. Among 6 patients with EOT PET/CT positive (Deauville 4), 4 underwent ctDNA monitoring, and 3 of them were negative, being still in continuous remission without any subsequent anti-tumor therapy.
CONCLUSION
CtDNA may be combined with PET/CT to assess efficacy, monitor relapse, and guide treatment of PMBCL.
Humans
;
Circulating Tumor DNA/blood*
;
Female
;
Mediastinal Neoplasms
;
Male
;
Retrospective Studies
;
High-Throughput Nucleotide Sequencing
;
Prognosis
;
Lymphoma, Large B-Cell, Diffuse/genetics*
;
Middle Aged
;
Adult
;
Aged
;
Neoplasm Recurrence, Local
;
Mutation
5.Cation Channel TMEM63A Autonomously Facilitates Oligodendrocyte Differentiation at an Early Stage.
Yue-Ying WANG ; Dan WU ; Yongkun ZHAN ; Fei LI ; Yan-Yu ZANG ; Xiao-Yu TENG ; Linlin ZHANG ; Gui-Fang DUAN ; He WANG ; Rong XU ; Guiquan CHEN ; Yun XU ; Jian-Jun YANG ; Yongguo YU ; Yun Stone SHI
Neuroscience Bulletin 2025;41(4):615-632
Accurate timing of myelination is crucial for the proper functioning of the central nervous system. Here, we identified a de novo heterozygous mutation in TMEM63A (c.1894G>A; p. Ala632Thr) in a 7-year-old boy exhibiting hypomyelination. A Ca2+ influx assay suggested that this is a loss-of-function mutation. To explore how TMEM63A deficiency causes hypomyelination, we generated Tmem63a knockout mice. Genetic deletion of TMEM63A resulted in hypomyelination at postnatal day 14 (P14) arising from impaired differentiation of oligodendrocyte precursor cells (OPCs). Notably, the myelin dysplasia was transient, returning to normal levels by P28. Primary cultures of Tmem63a-/- OPCs presented delayed differentiation. Lentivirus-based expression of TMEM63A but not TMEM63A_A632T rescued the differentiation of Tmem63a-/- OPCs in vitro and myelination in Tmem63a-/- mice. These data thus support the conclusion that the mutation in TMEM63A is the pathogenesis of the hypomyelination in the patient. Our study further demonstrated that TMEM63A-mediated Ca2+ influx plays critical roles in the early development of myelin and oligodendrocyte differentiation.
Animals
;
Cell Differentiation/physiology*
;
Oligodendroglia/metabolism*
;
Mice, Knockout
;
Mice
;
Male
;
Myelin Sheath/metabolism*
;
Humans
;
Child
;
Cells, Cultured
;
Oligodendrocyte Precursor Cells/metabolism*
6.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.
7.DHLX studied correlation between regulation of biliary flora and inflammatory factors on gallbladder stone formation
Yirong GAN ; Yuan YU ; Jinmei CHEN ; Chengji LI ; Wen YANG ; Jiaoan PANG ; Chunli LIU ; Lijun XIAO ; Jinhao TENG
Chinese Journal of Immunology 2025;41(3):644-649
Objective:By sequencing and analyzing the biliary flora by 16S rDNA high-throughput sequencing technology,to identify the main flora associated with gallbladder stone formation and the main flora regulated by the Dahuang lingxian(DHLX),pre-liminary investigation the effect of DHLX on the biliary flora.Methods:The 50 male guinea pigs were randomly divided into Normal group,Model group,DHLX group.There were 15 guinea pigs in the normal group and 20 guinea pigs in the DHLX group,and 20 guin-ea pigs in the model group:the guinea pig model of gallstone was replicated with high-fat lithogenic diet,which was simultaneously ad-ministrated by gavage.After continuous intervention for 8 weeks,bile and gallbladder tissue samples were collected,and the gallstone formation rate of guinea pigs in each group was calculated,the pathological morphological changes of gallbladder tissue were detected by HE,T-CHO,TBA,LPS,IL-6,TNF-α were detected by ELISA,and the changes of biliary flora were detected by 16S rDNA;the correlation between biliary flora and bile index was detected by Pearson statistical method.Results:The stone formation rate of guinea pigs in the normal group was 8.3%,the rate of model stone composition was 90.8%,and the stone composition rate of DHLX group was 36.4%,and the HE staining results showed that compared with the normal group,the mucous membrane of the guinea pig in the model group was thickened,the columnar epithelial cells were arranged in a large number of inflammatory cells,and the columnar epi-thelial cells of the gallbladder mucosa in the chinese medicine group were arranged neatly compared with the model group,the thick-ness of the mucosa was reduced compared with the model group,and some inflammatory cells were infiltrated;ELISA results showed that compared with the normal group,the expressions of T-CHO,LPS,IL-6 and TNF-α in the bile of guinea pigs in the model group were significantly increased(P<0.01),while the content of TBA was significantly reduced(P<0.01);compared with the model group,the expression of LPS and IL-6 in the bile of the DHLX group were significantly reduced(P<0.01).The results of 16S rDNA showed that compared with the normal group the Ace index and Chao1 index of the model group were significantly reduced(P<0.01),and the Chao1 index of the DHLX group was significantly higher than that of the model group(P<0.05);biliary flora at the genera level was mainly composed of Burkholderia,Sphingomycetes,Breghamus,Delfortella,Pseudomonas;correlation analysis showed that total cholesterol was negatively correlated with the abundance of Methyloversatilis(P<0.05),and total bile acids were positively corre-lated with the abundance of Burkholderia(P<0.05),and Pseudomonas erythrocytes,Rhizobia,the abundance of Phreatobacter was negatively correlated(P<0.01)and LPS was positively correlated with the abundance of Pseudomonas erythrocytes(P<0.01).Conclu-sion:Biliary microflora disorder exists in the formation of biliary stones,and biliary microflora may participate in the formation of stones by regulating cholesterol,bile acids and LPS.DHLX can regulate the changes in the abundance of the microflora,make the structure of the microflora become normal,reduce the inflammation of the gallbladder,and prevent the formation of gallstones.
8.Effect of donepezil combined with hypoxia on CYP3A4 and its safety-evaluation
Xiao-xia HAN ; Yue-xin LI ; Wei TENG ; Fang WANG ; Hai-ying HONG ; Ze-shuai YI ; Ying SONG ; Yu-yan ZHOU ; Bao-xin LI ; Pan FAN
Chinese Pharmacological Bulletin 2025;41(12):2354-2361
Aim To investigate the regulatory mecha-nisms of donepezil on the expression and enzymatic ac-tivity of cytochrome P450 3A4(CYP3A4),elucidate the synergistic impact of hypoxia on CYP3A4 function,and reveal its potential association with drug-induced cardiotoxicity,particularly QT interval prolongation.Methods Western blot,co-immunoprecipitation,and gene knockdown techniques were employed to evaluate the effects of donepezil and hypoxia on CYP3A4 pro-tein expression.CYP3A4 enzymatic activity was as-sessed using an in vitro incubation system with rat liver microsomes combined with high-performance liquid chromatography(HPLC),and the half-maximal inhib-itory concentration(IC50)was determined.Results Donepezil(10 μmol·L-1)and hypoxia reduced CYP3A4 protein expression to 31.75%and 45.90%of the control levels,respectively.Both interventions activated the gp78-mediated ubiquitin-proteasome path-way,significantly increasing CYP3A4 ubiquitination levels by 2.1-fold compared to the control group,thereby promoting proteasomal degradation.Donepezil inhibited CYP3A4 enzyme activity with an IC50 of 83.4μmol·L-1,and hypoxia synergistically enhanced this inhibitory effect,reducing the IC50 to 20.79 μmol·L-1.Conclusion Donepezil downregulates CYP3A4 function through dual mechanisms involving ubiquitin-mediated proteasomal degradation and direct enzymatic inhibition.Hypoxia potentiates this effect,leading to impaired metabolism of CYP3A4 substrate drugs,ele-vated plasma drug concentrations(1.6-2.3-fold in-crease compared to normal metabolic conditions),and an increased risk of QT interval prolongation and other forms of cardiotoxicity.
9.Melatonin Alleviates Spinal Cord Ischemia-reperfusion Injury in Rats by Inhibiting Neuron Pyroptosis
Qiu-ping HE ; Lei XIE ; Hai-ning PENG ; Xiao XIAO ; Teng-bo YU
Progress in Modern Biomedicine 2025;25(13):2081-2091
Objective:To investigate the effects of melatonin(MT)on spinal cord ischemia reperfusion injury(SCIRI)and its possible mechanisms in rats.Methods:Forty-two 6-week-old male Sprague Dawley rats were selected for the study and randomly divided into three groups:① Sham group(Sham group,n=14);② model group(model/SCIRI group,n=14);and ③ treatment group(MT group,n=14).Neurological function analysis was used to assess the motor conditions of rats in each group.Nissl staining and hematoxylin eosin(HE)staining were used to observe the number and morphology of neurons in each group,and TUNEL staining was used to evaluate the occurrence of apoptosis of neurons in each group.The expression levels of NOD-like receptor thermal protein domain-associated protein 3(NLRP3),apoptosis-associated speck-like protein(ASC),gasdermin D(GSDMD),the N-terminal fragment of gasdermin D(GSDMD-N),and cysteine proteinase 1(caspase-1)were evaluated using immunofluorescence,immunohistochemistry staining,and Western blot analysis.Results:Compared with the sham operation group,the neurological function score of the model group was significantly decreased,while the neurological function score of the treatment group was higher than that of the model group(P<0.05).The model group had fewer Nissl corpuscles compared with that in the sham operation group and abnormal neuronal morphology(P<0.05).Compared with the model group,the treatment group had a rise in the number of Nissl corpuscles and restored neuronal morphology(P<0.05).Compared with the Sham group,the number of apoptotic neurons increased in the model group,and the protein expression levels of NLRP3,ASC,GSDMD,and caspase-1 increased(P<0.05).Compared with the model group,The number of apoptotic neurons and the protein expressions of NLRP3,ASC,GSDMD and caspase-1 in the treatment group were significantly decreased(P<0.05).Conclusions:MT may alleviate spinal cord ischemia-reperfusion injury by inhibiting pyroptosis in neurons.
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.

Result Analysis
Print
Save
E-mail