Objective To clone and sequence variant-specific surface antigen gene from Giardia lamblia isolate SUCH/89/BTMRI/2(C2) derived from human in China. Methods Total genomic DNA of G.lamblia was extracted and a full-length variant-specific surface antigen gene fragment was amplified by pelymerase chain reaction (PCR). The PCR product was cloned into pMD19-T simple-vector, transformed into an Escherichia coli JM109 strain and then sequenced. The sequence analysis for cloned fragment was finished by Vector NTI 9.0 software for the homology of Giardia variantspecific surface antigen gene to that of sequences publishend in GenBank. Results The full-length variant-specific surface antigen gone fragment from G. lamblia was found to be 2 142 bp, encoding a 713 amino acid polypeptide and contained a single open reading frame (ORF). The deduced polypeptide sequence was rich in cysteine (11.8 mol%), most of which occurred with in 29 copies of the 4-amino acid CXXC motif, one GGCY-tetrapeptide motifs and three NXS consensus N-linked glycosylation sites. This polypeptide was also rich in threonine (10.2 mol%), glycine (12.1 mol%) and alanine (10.1 mol%). Like other previously identified VSPs, it contained a highly conserved hydropbebic Cterminal region. The homology of G. lamblia SUCH/89/BTMRI/2(C2) variant-specific surface antigen gene to that of sequence (TSA417) published in GenBank was 99% both at the nueleotide and the amino acid levels. Conclusion The full length variant-specific surface antigen gene from the isolate of G. lamblia has the common characteristics with other previously identified VSPs.

Objective:To explore the cooperation and clinical significance of HIF-1α,ALDH1 and Hedgehog signaling pathway in the activation of cancer stem cell(CSC) in triple negative breast cancer(TNBC).Methods: ALDH1+(Aldehyde dehydrogenase1)breast cancer stem cells and ALDH1-breast cancer cells were selected from MDA-MB-231 cells by magnetic activated cell sorting system(MACS),qRT-PCR method was employed to analyze the expression differences of HIF-1α and Hedgehog signaling molecules Sonic hedgehog(SHH),patched1(PTCH1),Smoothened(SMO) and Glioma-associated oncogene homoglog1(GLI1) in ALDH1+ breast cancer stem cells and ALDH1-breast cancer cells.Immunohistochemical method was applied to study the expressions of HIF-1α and ALDH1 and the relationships among HIF-1α,ALDH1 and Hedgehog signaling molecules in TNBC.Results: The expressions of HIF-1α mRNA,SMO mRNA and GLI1 mRNA in ALDH1+ breast cancer stem cell were higher than those in ALDH1-breast cancer cell(P all<0.05).The positive expression rates of HIF-1α were 90.0% and 70.0%,and the positive rates of ALDH1 were 93.3 % and 66.7 % in TNBC and non-TNBC,respectively(P all<0.05).Spearman rank correlation analysis showed that the expression of HIF-1α was positively related with that of ALDH1 in TNBC(r=0.53,P<0.01).HIF-1α expression was correlated with lymph node metastasis and TNM stage(P all<0.05),ALDH1 expression was correlated with histological grade and TNM stage(P all<0.05).In addition,the expression of HIF-1α was positively related with that of Hedgehog signaling molecules SHH(r=0.584,P<0.01),SMO(r=0.467,P<0.01) and GLI1(r=0.439,P<0.05),the expression of ALDH1 was positively related with that of SHH(r=0.426,P<0.05) and GLI1(r=0.394,P<0.05).Conclusion: HIF-1α and Hedgehog signaling pathway were activated in ALDH1+ breast cancer stem cell.HIF-1α,ALDH1 and Hedgehog molecules may cooperate with each other to activate breast CSC to promote the malignant progression of TNBC.