Identification Of Biological Characters In The Shr Strain Of Toxoplasma Gondii

Abstract:A rare strain of Toxoplasma gondii type III was isolated from a rabbit of Shanghai in our laboratory,and we named it as SHR.We conducted this study due to the specificity for type III T.gondii strains in china.1.PCR-RFLP method was used to identify the genetic type of the strain of SHR and RH.Four genetic markers(L358,C29-2,SAG1 and PK1)of the four isolates were obtained by PCR.Digestion of these four loci with appropriate endonucleases come out the result.2.In this experiment,Mice were inoculated intraperitoneally with 1×104achyzoites of SHR strain.Drugs were administrated three hours post-infection,once per day for 5 consecutive days,and the first dose was reduplicated.The survival time and survival rate of mice were observed for continued 20 days.we analysed the therapeutic effect of azithromycin,sulfachloropyrazine sodium,acetylspiramycin and paromomycin against the infected of SHR strain,in order to explore the best drug for treatment of the SHR infection.Two rabbits were infected tachyzoites of the SHR by intravenous injection,The infection dose was 1×104.Every 3 days post inoculation(p.i.),the serum from each rabbits was sampled and numbered for examination of ELISA;14 chickens were inoculated intraperitoneally with 1×107tachyzoites of SHR strain,on the day(3,6,9,12,15,22,29)post inoculation(p.i.),the serum from each chickens was sampled and numbered for examination of ELISA.4.12 rabbits were infected tachyzoites of the SHR by intravenous injection,The infection dose was 1×104.Every 10 days post inoculation(p.i.)2 rabbits were sacrificed and the heart,liver,spleen,lungs,kidneys,and brain were removed and cleaned with ddH20,and the DNA was then extracted using a DNA extraction kit;14 chickens were inoculated intraperitoneally with 1×107tachyzoites of SHR strain,on the day(3,6,9,12,15,22,29)post inoculation(p.i),2 chickens were sacrificed and the heart,liver,spleen,lungs,kidneys,and brain were removed and cleaned with ddH20,and the DNA was then extracted using a DNA extraction kit;The results indicated that the l,the genetic type of the strain of SHR is type ? and RH is type 1.2,azithromycin showed the best therapeutic effect.Acetylspiramycin also has a better therapeutic effect.The Sulfaclozine sodium can only delay the survival time,while paromomycin showed no therapeutic effect.Azithromycin has the best treatment for the mice infected with SHR.3.For the rabbits,antibody titer gradually increased over time,there are some peak in the experiment,and the first peak appears on the 18 day of infection.After the 90 days of infection,the antibody titers of the infected rabbit remains in a high state;For the chickens,antibody titer gradually the first peak appears on the 15 day of infection.After the 15 days of infection,antibody titer gradually decreased,on the 29 day of infection,the volume of OD was 0.3.4.For the rabbits,SHR can affect the heart?liver?spleen?lung?kidney and brain of the rabbit.With the extension of the time of infection,the SHR changes the site of infection.After 50 days post inoculation(p.i.),we can only test the SHR on in the brain;For the chickens,on the 3 day after infected,we can test the SHR in the live?kidney and brain,on the 6 day after infected,we can test the SHR in the liver?spleen?lung?kidney and brain,after the 6 day,we can not test SHR in any organs.