| Mycoplasma Gallisepticum (MG) infection have also been called Chronic Respiratory Disease (CRD). With the increasing of stress and incensitive rearing, change of rearing method and high rearing density, Mycoplasma Gallisepticum (MG) infection have already been a major problem that affects the poultry industry through its increased morbidity. MG infection can be easily triggered under such environment as poor ventilation , a sudden air temperature change and excessive ammonia and dusts ,even after vaccinating the live vaccine such as Newcastle disease, Infectious bronchitis and Infectious Laryngotracheitis can also triggered this disease. The clinical infection is characterized by coughing, nasal discharge, rattling and forced-breathing. Mycoplasma Gallisepticum appears to be a world –wide distribution. Infection with Mycoplasma Gallisepticum is spread by aerosol exposure and egg transmission ,consequently, it can be exist and spread in flock for a long time .According to the serological investigation and statistics, the average infection rate in flocks were 50%-80% , when catching this disease, the unhealthy chicken rate increased about 10%, egg production of layer dropped 10%-20% ,weight lost 38%.,the period of onset to market prolonged , feed conversion efficiency reduced 20%. This arouse considerable drug cost ,at the same time ,it could cause drug-remain in poultry products. A lot of countries have taken importance to preventing this disease for many years, but a kind of reasonable preventive way have not been found until now. The development of molecular biology techniques have opened up a new path to prevent this disease. Although the molecular biology research on MG have made great progress , there is still few reports on protective antigen ,gene cloning and gene expression of MG in our country. Up to the present, any studies on gene vaccination of MG have not been reported. There are the reports on diagnosis the MG through agglutination test and pathological test , but until now, no research has been conducted on isolation ,identification and molecular biology of MG in Inner Mongolia autonomous region. Aiming at the present research condition of Mycoplasma Gallisepticum infection in this region , we studied the isolation and gene vaccination of MG, through this study, such results have been gained:1.Using serum plate agglutination test to learn the MG infection condition of some chicken from four poultry factory in Hohhot and Baotou in Inner Mongolia autonomous region, the results showed that average positive rate of MG infection were 84%, this results indicated that MG have already wide-spread existed in our region.2.Three stains of mycoplasma were isolated from 39 chickens which coming from four poultry factory in Hohhot and Baotou in Inner Mongolia autonomous region, after identification , two stains are MG, named H3 strain and BR1 strain respectively, another stain were first judged as mycoplasma gallinarum which named BR2 strain.3.It proved that H3 strain and BR1 strain were both virulent strain through challenge.4.It proved that H3 Stains has high immunogenicity through vaccinating the SPF chickens with self-made oil emulsion vaccine.5.Through amplified by PCR ,we succeed in cloning the TM-1gene of H3 strain, after DNA sequencing and the deduced amino acid comparison ,the results showed that the different rate of nucleotide between TM-1 gene of H3 strain and S6strain were 3.435%, and that of amino acid were 4.581%.6.It proved that TM-1gene can be expressed in E.coli through PET-30a prokaryotic expression vector, and the expressed protein have immunoreactivity.7.We succeeded in construction the eukaryotic expression plasmid of TM-1 gene.8.Through vaccinating SPF chicken , it proved that the eukaryotic expression plasmids of TM-1 gene could induced humoral immunity and cellular immunity of the chicken through ELLLSA and flow cytometry(FCM)9.After challenge, it proved that the DNA vaccine that we constructed can produced the same immunity effect as that of oil emulsion vaccin...
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