ABSTRACT
Objective: To observe the expression of miR-451 during erythroid differentiation of K562 cells and investigate the role of miR-451 in erythroid differentiation. Methods: MiR-451 expression was analyzed in different tissues (the liver, bone marrow, erythrocytes, and white blood cells) of mice, human erythrocytes, and chicken red blood cells by Northern blotting. Erythroid differentiation of K562 cells was assessed by DAB staining and RT-PCR of heamoglobin mRNA before and 36 h after hemin induction (50 μmol/L). The expression of miR-451 in K562 cells was further explored by Northern blotting and stem-loop RT-PCR before and 24,48,72,and 96 h after hemin induction (50 μmol/L). Results: Expression of miR-451 was only identified in the erythrocytes, not in white blood cells, hepatic cells or bone marrow of mice. MiR-451 expression was also detected in human erythrocytes and chicken erythrocytes with nuclei. Two bands were detected in the human and mouse erythrocytes by Northern blotting, indicating that, in addition to the one reported by Sanger's miRBase, there was another miR-451 sequence which had additional uracil residue in 3′ terminal. Hemin induced differentiation of K562 cells and DAB staining showed more positive cells after induction (P<0.05); the expression of γ, δ and -̇globin mRNA was also increased after treatment with hemin (P<0.05). Although Northern blotting revealed no changes in miR-451 expression in K562 cells after hemin induction, more sensitive stem-loop RT-PCR showed that miR-451 expression, which maintained at lower level in un-induced K562 cells, was increased during erythroid differentiation 24 h after hemin induction. With the upregulation of δ-globin protein, the expression of miR-451 reached its peak 72 h later. Conclusion: miR-451 is specifically and highly expressed in erythroid terminal differentiation. Two different sequences of miR-415 (one with and additional uracil residue) are present in the human and mouse erythrocytes, and their expression is elevated during the erythroid differentiation of K562 cells.
ABSTRACT
Objective To understand the level and distribution of antibody F1 against plague in population of Ningxia natural plague foci in 2007 and 2008. Methods Seven hundred and eighteen blood samples were collected in five major cities and counties of natural plague foci, and 475 blood samples were collected in nonplague area as control group. Conventional indirect hemagglutination, colloidal gold test, and enzyme-linked immunoassay were employed to test the antibody. If the result was tested positive by more than two methods used then the result was defined as positive. Antibody titer that did not reach the positive standard was defined as suspected samples. Results A total of 718 serum samples were tested, the results showed that 9 samples were positive (antibody titer was 1:16 - 1:64), the positive rate was 1.25%(9/718), suspected samples was 28, the detection rate was 3.90%(28/718). Four hundred and seventy-five serum samples in the non-plague area were all negative by the three methods. There was a significant difference of antibody F1 positive rate between residents in historical epidemic area and history nonepidemic area(χ2 = 4.44, P< 0.05). There was no statistical significance of the positive rate[1.25%(9/718), 1.25%(9/718),2.51%(18/718)]among the three methods used(χ2 = 1.91, P> 0.05). Conclusion There still exists a certain proportion of Fl antibody positive people in Ningxia natural plague foci, and these people are distributed in areas where several animal plague prevalent in recent years.
ABSTRACT
Objective To establish a method for detection of the human papi 11 omavirus(HPV)6b E7-specific antibodies in serum and cervical secretion from patients with condyloma acuminatum(CA).Methods A full-length HPV 6b E7 gene was amplified by PCR from the CA tissue to construct the recombinant plasmid pET32a(+)/HPV 6b E7.The expression of prokaryotic protein was analyzed by SDS-PAGE and Western blot,then purified with Ni-NTA Agarose affinity column and used as an diagnostic antigen for establishing indirect ELISA method,to detect specific serum IgG and specific cervical secretion slgA from 56 CA patients,81 healthy control.Sera from 43 cervical cancer was served as control.HPV 6b DNA from 56 CA patients was identified by PCR.Results Data showed that the nucleotide homology of cloned sequence was 99.5%,compared to the standard sequences of HPV 6b E7 gene(GenBank accession number:NC001355).A high level expression of E7 fusion protein was obtained in prokaryotic expression system(40 μg/ml).Based on HPV 6b E7 fusion protein being used as coating antigen,results from ELISA showed that the absorbance rates(A)of serum IgG from CA,cervix cancer and healthy control groups were 1.82±0.48,1.36 ± 0.39 and 1.39 ± 0.27,respectively.The level of IgG antibody in the serum of CA group was significantly higher than that in cervix cancer group and healthy control(P＜0.05).The A values of cervical secretion sIgA in CA and healthy control groups were 0.63 ± 0.26 and 0.53 ± 0.06,respectively,while the level of sIgA antibody in the cervical secretion of CA group was also significantly higher than that in healthy controls(P＜0.05).The positive rate of HPV 6b E7 DNA in CA tissue was 78.6%(44/56)by PCR method.When compared the results measured by PCR,the HPV 6b E7-specific IgG and sIgA antibodies by ELISA used to detect the patients infected with HPV 6b infection,showed that the sensitivity rates were 68.2%(30/44)and 54.6%(24/44)respectively,and the specificity were all 100%(12/12).Conclusion Based on the serum and cervical secretion specific HPV 6b E7 antibodies from patients with CA to diagnose HPV 6b infection,results showed medium sensitivity and high specificity,and could further be used to investigate the epidemiological characteristics of HPV 6b infection.