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.

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.

Objective: Moxifloxacin (MFX) shows good activity against and can be a possible antibiotic therapy to treat infection; however, other studies have shown a lower or no activity. We aimed to evaluate MFX activity against using zebrafish (ZF) model . Methods: A formulation of labeled with CM-Dil was micro-injected into ZF. Survival curves were determined by recording dead ZF every day. ZF were lysed, and colony-forming units (CFUs) were enumerated. Bacteria dissemination and fluorescence intensity in ZF were analyzed. Inhibition rates of MFX and azithromycin (AZM, positive control) were determined and compared. Results: Significantly increased survival rate was observed with different AZM concentrations. However, increasing MFX concentration did not result in a significant decrease in ZF survival curve. No significant differences in bacterial burdens by CFU loads were observed between AZM and MFX groups at various concentrations. Bacterial fluorescence intensity in ZF was significantly correlated with AZM concentration. However, with increasing MFX concentration, fluorescence intensity decreased slightly when observed under fluorescence microscope. Transferring rates at various concentrations were comparable between the MFX and AZM groups, with no significant difference. Conclusion MFX showed limited efficacy against using ZF model. Its activity needs to be confirmed.
Animals ; Anti-Bacterial Agents ; pharmacology ; Disease Models, Animal ; Moxifloxacin ; pharmacology ; Mycobacterium Infections, Nontuberculous ; drug therapy ; Mycobacterium abscessus ; drug effects ; Zebrafish

Objective In this study we investigated the functional restoration of nonsense mutations in the SCN5A gene. Methods The readthrough-enhancing reagents were introduced to HEK293 cells to suppress one nonsense mutation W822X in the SCN5A gene. Patch-clamp was used to record the whole-cell current and dynamics. Western blot and immunofluorescence staining were used to certify the expression and the location of the sodium channel. Results In transfected HEK293 cells, the nonsense mutation in SCN5A inhibited the expression level of full-length protein, and the sodium currents from the mutant channels were less than 3% of the wild-type level. Readthrough enhancement by decreasing translation termination efficiency with a siRNA targeting eukaryotic release factor eRF3a ( a GTPase that binds eRF1 ), the sodium current from the mutant cDNAs was restored to as much as 30% of the wild-type. After the treatment by the readthrough-enhancing reagents, the channels from cDNA carrying W822X remained the features of wild-type phenotype, and Western blot and immunochemical staining also showed the expression of full-length channel proteins. Conclusion Readthrough-enhancing reagents could effectively suppress nonsense mutations in SCN5A and partially restore the function of sodium channel and the expression of full-length channels.

OBJECTIVETo investigate the inhibitory effects of antisense oligonucleotides to different sequences on VEGF gene expression by human hepatoma cells.

METHODSSMMC7721 cells were cultured under normoxic or hypoxic conditions for 24 h, followed by being transfected with different antisense oligonucleotides (A06513 to cap structure, A06514 to translation initiation, A06515 to Exon-3 and A06516 to translation terminal). The total RNAs from the cells were extracted and the VEGF expression were examined with RT-PCR. The relative concentrations of VEGF transcripts in SMMC772 cells from different groups were determined using GAPDH (glyceraldehyde-3-phosphate dehydrogenase) cDNA as internal standard.

RESULTSIn response to the hypoxic challenge, SMMC7721 cells upregulated VEGF mRNA; Comparative to the control (no oligonucleotides), A06513, A06514, A06515, and A06516 had obvious sequence-specific inhibitory effect on VEGF gene expression, with the ratio of VEGF over GAPDH of 0.49+/-0.08, 0.71+/-0.12, 0.72+/-0.11 and 0.86+/-0.12, respectively (F=12.21, P< 0.05). A06513 showed the strongest inhibitory effect (P<0.01).

CONCLUSIONThe antisense oligonucleotides complementary to VEGF cap structure, may become a potential alternative for antisense gene therapy of HCC.

Gene Expression Regulation, Neoplastic ; Humans ; Liver Neoplasms ; genetics ; therapy ; Oligonucleotides, Antisense ; pharmacology ; Reverse Transcriptase Polymerase Chain Reaction ; Vascular Endothelial Growth Factor A ; antagonists & inhibitors ; genetics

Animals ; Arthritis, Rheumatoid ; blood ; drug therapy ; Drug Therapy, Combination ; Drugs, Chinese Herbal ; therapeutic use ; Interferon-gamma ; blood ; Phytotherapy ; Tumor Necrosis Factor-alpha ; metabolism

Objective To evaluate the effects of small interfering RNA(siRNA)against Ki67 gene on the proliferation and apoptosis of human renal carcinoma cell line 786-0 cells.Methods The human renal carcinoma 786-0 cells were treated with Ki67-siRNA(100 nmol/L).The mRNA expression of Ki67 was detected by RT-PCR.The protein expression of Ki67 was detected by Western blot and immunohisto- chemical technique,respectively.The proliferation of 786-0 cells was detected by MTT assay.The apoptosis of 786-0 cells was detected by TUNEL assay.Results RT-PCR and Western blot analysis showed that the Ki67 mRNA and Ki67 protein expression levels of the 786-0 cells treated with Ki67-siRNA were(37.6?1.9)% and(46.4?0.9)% ,respectively,which were significantly lower than those of controls [(97.3?0.9)% and(95.3?0.9)%,P＜0.01],The Ki67 positive expression rate of 786-0 cells treated with Ki67-siRNA by immunohistochemical technique was 52.5?2.3,which was significantly lower than that of controls(114.5?4.9 ,P＜0.01).The proliferation-inhibiting rate and apoptosis rate of the 786-0 cells trea- ted with Ki67-siRNA were( 63.6?1.6)% and(41.7?0.6)% ,respectively,which were significantly higher than those of controls [(2.8?0.2)% and(10.3?1.4)%,P＜0.01].Conclusions siRNA against Ki67 gene can inhibit the proliferation and induce the apoptosis by blocking Ki67 expression of hu- man renal carcinoma 786-0 cells.The inhibition of Ki67 expression by siRNA may be a promising approach in gene therapy for renal cancer.