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Objective To observe and identify the microorganism isolated from diseased and dead Ctenogobius gymnauchen cultured in seawater near the Daya Bay of south China sea.Methods GDLAMI-1210 strain was isolated from the diseased Ctenogobius gymnauchen(Bleeker).We applied physiological and biochemical characteristics in the bacterial classification.In order to confirm the results,we amplified a 1438 bp sequence of GDLAMI-1210's 16 S rRNA(HM 362434)and compared with other sequence in GenBank,and followed by artificial infection.Results The GDLAMI-1210 strain was Gram-negative and in a shape of short rod with single polar flagellum.The homology analysis and phylogenetic study showed that the 16 S rRNA sequence of GDLAMI-1210 has the highest similarity to Vibrio sp.espec Vibrio vulnificus,showing 99% identity.Conclusions To our knowledge,this is the first report that the causative pathogen,Vibrio sp,leads to the mortality of Ctenogobius gymnauchen(Bleeker).
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Objective To investigate the natural infection of Theiler's murine encephalomyelitis virus (TMEV) in mice,and to survey the distribution of virus in tissues and the changes of serum antibody in the experimentally TMEV-infected mice.Methods Enzyme linked immunosorbent assay (ELISA) and fluorescence quantitative RT-PCR (qRT-PCR) assay were used to detect the antibody and nucleic acid of TMEV in clinical samples.These samples included SPF mice collected from Guangdong area in 2010-2015,mice obtained from a non-barrier laboratory rodent colony,and wild Rattus norvegicus live-trapped around the non-barrier laboratory rodent colony.36 ICR mice were intracerebrally inoculated with TMEV BeAn strain.The clinical signs of the animals were observed daily post-inoculation.Three mice were euthanatized at day 0,3,7,10,17,21,31,39 and 46 post-inoculation (dpi),respectively.Tissue and serum samples were collected for TMEV detection.Results The TMEV antibody and nucleic acid positive rates of SPF mice collected from Guangdong area in 2010-2015 were 5.29％ (n=2834) and 27.27％ (n=457),respectively.The TMEV antibody and nucleic acid positive rates of the mice obtained from a non-barrier laboratory rodent colony were 71.95％ (n=82) and 53.66％ (n=82),respectively.The TMEV nucleic acid positive rate of wild Rattus norvegicus was 25.93％ (n=27).In the TMEV positive mice,only two mice showed obvious clinical symptoms.The cecal contents,feces and brain samples were the best candidates for qRT-PCR assay.The viral nucleic acid could be detected in the brain,heart,liver,lung and stomach of ICR mice at 3 dpi,but no viral nucleic acid was detected in the spleen,kidney,and cecum.The viruses in liver,heart,lungs and stomach were completely cleared at 10 dpi,and the viruses persisted in the brain throughout the experiment.The TMEV antibody could be detected at 7 dpi,and then the antibody positive rate reached 100％ at 17 dpi.The antibody level increased gradually and maintained up to 46 days.ICR mice showed latent infection after TMEV inoculation,with no obvious symptoms and eye pathological changes.Conclusions The experimental mice and wild Rattus norvegicus in Guangdong area are both infected with TMEV,and the infection rate is high.The mice inoculated with TMEV BeAn strain show latent infection.The TMEV antibody produced in mice can be detected at 7 dpi and persisted until the end of the experiment.The viruses are found in the liver,heart,lung and stomach for a short time,but are persisted in the brain for a long time.There is a good consistency of TMEV detection between qRT-PCR and ELISA.The qRT-PCR assay can be used as a powerful complement method for the national standard of laboratory animals.
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Objective To establish a mouse model of systemic C. albicans infection by oral inoculation of the pathogen and observe the proliferation and distribution of C. albicans in vivo tissues. Methods Male ICR mice(n=46) were used as the experiment group(n=40) and blank group (n=6). Cotton swabs with C. albicans were used to infect the mice (7 × 106 CFU/mL), and the blank group with saline. The mice of the experiment group were randomly divided into two groups:model group A for clinical assessment (n=20) and model group B for tissue fungal burden detection (n=20). Clinical score, survival and autopsy were carried out among the model group A. Five mice were randomly killed from the model group B at 3 d, 5 d and7 d after infection, respectively ( blank group killed 2 mice each time) . Microbial load tablet method was used to detect the tissue fungal burdens in different tissues, meanwhile samples of tongue, esophagus, stomach, liver, kidney, lung of infected mice were taken for pathological examination. Results White spot appeared on the surface of tongue since 3 d postinfection and increased with time and finally caused death. The mortality reached over 50% at 5 d. C. albicans was not only detected from the tongue (87?5%), stomach (87?5%), liver (54?5%), kidney (50?5%), lung (20%) and heart (4%), but also was microscopically seen mycelia proliferation in the tongue, stomach, liver, and kidney , yet not seen in the control group, showing that C. albicans caused disseminated systemic infection through mucosal infection in mice. Conclusions C. albicans can induce opportunistic systemic infection by breakthrough the mucosal immune barrier, so as to increase the infection to death.
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Objective To assess the potential of whole blood IFN-γassay for diagnosing mycobacterium in rhesus macaques.Methods Firstly, basic serum IFN-γconcentrations of TST-negative and -positive rhesus macaques were detected.Then, heparinized whole blood from TST-negative and-positive rhesus macaques was incubated with PBS and 200 IU bovine-PPD ( tuberculin purified protein derivative ) for about 24 h, respectively.The supernatant plasma were harvested and used to determine the concentrations of IFN-γ.The results of plasma IFN-γconcentrations and stimulation index ( SI) were used to analyze the diagnostic potential of the whole blood IFN-γassay.Results The basic serum concentrations of IFN-γfor the TST-positive monkeys were significantly higher than that of the TST-negative macaques, showing a high coefficient of variation.There was no significant effect on the production of IFN-γin the TST-negative macaques.While significantly elevation of IFN-γconcentrations was found in stimulated plasma of TST-positive macaques (P<0.01).The SI of TST-positive macaques was significantly higher than the TST-negative ones.ROC curve analysis revealed that IFN-γconcentrations and SI could be used as evaluation index of whole blood IFN-γassay.Conclusions Based on a small sample experiment we have demonstrated that whole blood IFN-γassay may be one possible auxiliary diagnostic method for tuberculin skin test.
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Objective To screen strains of minipigs sensitive to highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) for evaluation of HP-PRRS live vaccine.Methods Lantang pigs, Juema, Bama and Wuzhishan ( white) minipigs were inoculated with virulent strain NVDC-JXA1 of PRRSV, and local binary hybrid pigs were used as control.The animals were continuously observed for 5 weeks on mental status, appetite, survival, etc.after inoculation of virus.The dead pigs were autopsied and the lung tissue samples were collected for detecting virus by RT-PCR.By the end of the experiment, serum of survival animals were collected for detecting PRRSV antibody by ELISA assay.Result The animals showed depression, anorexia, and other clinical signs and death in each group after inoculation.Meanwhile, the testing results were all positive in the RT-PCR and ELISA detection.Bama and Wuzhishan ( white) minipigs were the most sensitive to virulent strain NVDC-JXA1 of PRRSV regarding mortality rate.Conclusions Bama and Wuzhishan ( white) minipigs are sensitive to HP-PRRSV, and can be used for the inspection of HP-PRRS live vaccine.
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Objective To measure the organ weight and body weight of outbred Wuzhishan mini-pigs (WZSP), and calculate the organ coefficient and the linear and multiple linear regression equations between body weight and major organ weights. Methods 30 common WZSP (16 males and 14 females) were chosen,the body weight and 7 organ weights were determined, and the organ coefficients were calculated. The organ coefficients between males and females were compared. The correlation and regression analysis was performed using the SAS software. Results The coefficient of heart had remarkably significant difference between males and females (P<0.05).The linear analysis showed that there were apparent linear correlations between body weight and all the organ weights except for the stomach of males and the lung of females.The weights of liver and kidney showed great influence on the body weight of males, while the body weight of females relied on the weights of heart, liver and kidney greatly. Conclusion Differences of organ coefficients are not significant between males and females,and there are linear relationships between body weight and some major organ weights.