The Cloning And Sequence Analysis On Acta,inlb And Distribution In Artificial Infectious Mice Disease Model For Listerial Monocytogenes

Listeria monocytogenes (LM),It caused by Listeria monocytogene.It has invasiveness on human,domestic animal,domestic fowl,wildness.It can cause encephalitis,septicaemia and embryotocia,having the significant importance on public health.Recently,the pathogenic mechanism on human and animals by listeria monocytogenes become hot spot.Through determining the LD50 of the scal-2 and sheep-90,artificial infecting mouse model was built.Distribution of Listeria monocytogenes and pathological changes in different organs were studied in artificial infected mice disease model by the method of PCR,fractional cultivation and pathohistoloy as well as cloning actA and in1B virulence factor, The research discovered:First,The LD50 of the scal-2 is 3.8×107CFU/ml;that of sheep-90 is 4.180×107CFU/ml. It is indicated that the virulence of the scal-2 is stronger than sheep-90.Second, Listeria monocytogenes sheep-90 and its DNA could be detected in spleen, liver,kidney, cardiac muscle in artificial infectious mouse at 2h following infection. Listeria monocytogenes DNA could be detected in encephalon at 6h, Listeria monocytogenes can be detected in the encephalon at 72h. Significant histopathological changes were observed during 4-6h in spleen,kidney,cardiac muscle,liver,encephalon; nevertheless after mice infected by scal-2 are killed, Listeria monocytogenes and its DNA can be detected in spleen, liver,kidney, cardiac muscle in artificial infectious mouse at 2h., its DNA can be detected in encephalon at 8h,Listeria monocytogenes can be detected in the encephalon at 72h. Significant histopathological changes are observed after 6h in spleen,kidney,cardiac muscle,liver,encephalon.Third, DNA fragment of actA and in1B gene were amplified from the chromosomal DNA of 9 Listeria monocytogenes Inducing sheep Encephalitis by PCR,there are scal-2 and S-90 which have avtA structure gene,there are scal-2,S-90 and SB5 which have in1B structure gene;cloning the actA and in1B production of PCR into pMD 19-T Vector and the cloned fragment was sequenced after identified by PCR and two restriction enzyme digestion, DNA sequence comparison of the amplified fragment of S-90,scal-2 with the published sequence of gene actA in Genbank showed 92.71% and 99.10% nucleotide homology. DNA sequence comparison of the amplified fragment of S-90,scal-2 with the published sequence of gene inlB in Genbank showed 92.54% and99.68% nucleotide homology. It is indicated that there are certain contact among Listeria monocytogenes.Through the above research, The valuable test data have been provided for Investing the pathopoiesis mechanism of Listeria monocytogenes of human and creature,the foundation will be settled for studying molecule mechanism.