This review focuses on biological characteristics of Echinococcus f elidis including molecular genetic markers , species status ,host coverage ,geographical distribution ,epidemiological implications ,phylogeny ,and evolution .The molecular genetic markers are involved in mitochondrial cox1 (cytochrome C oxidase subunit 1) and nad1 (nicotinamide adenine dinucle-otide dehydrogenase subunit 1) genes ,nuclear protein-coding gene sequences such as elp (ezrin-radixin-moesin-like protein) , e f1a (elongation factor 1 alpha) ,pepck (phosphoenolpyruvate carboxykinase ) ,pold (DNA polymerase delta ) ,and ribosome RNA gene sequences such as ITS1 and 18S rRNA .The establishment of species status is based on distinctly discriminated mor-phological characteristics such as hooks on the rostrum with apparent rugae ,the special definitive host (lions) ,and divergence of DNA sequences ,etc .between E . f elidis and other Echinococcus species .In brief ,the review has provided researchers and ex-perts in the field of echinococcosis with fundamental background knowledge and guidelines for future research directions ,clinical and epidemiological investigations ,and prevention and control of echinococcosis .

Echinococcosis (hydatid disease) caused by the metacestodes of Echinococcus granulosus tapeworm is a seri-ous zoonotic infection ,which leads to a large amount of economic loss in human and animals .It needs to be prevented urgently . The EG95 protein is highly conserved and crucial for survival and development of E .granulosus in the host ,which means that it is one of the potential candidate antigens for vaccines characterized so far .Great effort has been made to construct and ex-press the recombinant EG95 (rEG95) gene in various kinds of expression systems in order to obtain an efficient defined antigen . This review will summarize research progress on expression of rEG95 in different vector systems .

Three pairs of specific primers were designed to amplify the F2-1, F2-2 and XF2-2 truncated sequences of ORF2 which encodes the capsid protein of porcine circovirus type 2 (PCV-2). The F2-1 sequence had most of the NLS region of ORF2, but the F2-2 and XF2-2 genes had the NLS region deleted. Truncated genes were subcloned into pET-32a(+) vectors to construct recombinant fusion expression vectors. The vectors were then transformed into Rosetta(DE3) E. coli and expressed by induction of IPTG. Expressed proteins were detected by western blotting and ELISA. The protein with best immunoreactivity was confirmed and selected, then utilized to inoculate SPF rabbits to prepare polyclonal antibodies. The protein and prepared polyclonal antibody were utilized to detect sera samples against PCV-2 from Shandong province and PCV-2 particles in PK-15 cells. In our study, three recombinant fusion proteins were successfully obtained, and the molecular weights of fusion proteins were 35.9 kDa, 33.6 kDa and 38.6 kDa respectively detected by SDS-PAGE. All of the proteins showed positive reaction with anti-PCV-2 antisera, and His-XF2-2 showed better immunoreactivity than the others. The protein of His-XF2-2 was coated as antigen in ELISA to detect the seroprevalence of PCV-2 in certain districts of Shandong province, the seropositivity rate was 27.7 % (73/264). Specific fluorescence and positive signals for PCV-2 could be detected in PK-15 cells inoculated with PCV-2 with the participation of prepared antibodies against His-XF2-2 in IFA and IPMA. Experimental results indicated that the truncated PCV-2 ORF2 gene containing most of the NLS region was successfully expressed in E. coli, and His-XF2-2 was demonstrated to have better immunoreactivity with anti-PCV-2 antisera than the other two fusion proteins. His-XF2-2 and prepared polyclonal antibodies against it had a satisfactory capability in detecting PCV-2 infection.

The structure genes spike (S), nucleocapsid (N), membrane (M), small membrane (sM) of a porcine epidemic diarrhea virus (PEDV) strain DX isolated in Gansu province, North-west of China, were cloned, sequenced and compared with published sequences of PEDV strains. The nucleotide sequences encoding the entire S, sM, M and N genes open reading frame (ORF) of DX were 4 152, 231, 681 and 1 326 bases long respectively. There were transcription regulatory sequences (TRSs) upstream of the initiator ATG of the S, N and M genes. The amino acids sequences of S, M and N contained 30, 3 and 7 potential asparagine (N)-linked glycosylation sites. Homologous analysis and phylogenetic trees showed that DX had the closest relationship with strains LJB/06, JS-2004-2Z and CH/HLJH/06 that were also isolated from China and indicated the prevalence of some PEDV isolates in China were widespread since the JS-2004-2Z strain originated from the south of the China, and LJB/06 and CH/HLJH/06 were isolated from northeast China. The N gene was cloned using two primers which contained Nco I and BamH I restriction enzyme sites and subcloned into expression vector pET30a. The recombinant plasmid was then transformed into E.coli Rossta. SDS-PAGE showed there was a protein of about 55kDa as expected and Western blot indicated the N protein had biological activity.