Abstract: Objective To construct a shuttle vector pHT315-AaCPR100A with two spore-producing-dependent promoters and the target gene AaCPR100A in Escherichia coli-Bacillus thuringiensis. Methods The forward promoter of Cry3A, named Pro-1 (+), was amplified by PCR using pSVP27A plasmid as the template, and the target gene AaCPR100A was amplified using Aedes aegypti RNA reverse conversion cDNA as the template. The plasmid pHT315 was linearized by digestion with Hind Ⅲ and Sal Ⅰ. The forward promoter and the target gene were inserted into the linearized vector pHT315 successively by in-fusion cloning according to the transcription direction. The synthesized plasmid containing the Cry3A reverse promoter sequence was used as the template, and the Pro-1 (-) reverse promoter was amplified by PCR. The intermediate vector containing the forward promoter and the target gene was linearized by EcoR I restriction enzyme, and the reverse promoter was inserted downstream of the target gene by in-fusion cloning in the direction of transcription. Results By agarose gel electrophoresis, the forward promoter, target gene AaCPR100A and reverse promoter bands were clear and of good quality, which could be used for in-fusion cloning experiments. The two spore-producing-dependent promoters and target gene fragments were connected by In-fusion cloning. The recombinant vector pHT315-AaCPR100A was verified by PCR. The forward promoter, target gene fragment and reverse promoter were successfully amplified in the recombinant vector. Nucleotide sequencing verified that the sequencing results of the bidirectional promoter sequence and the target gene sequence were basically consistent with the sequence alignment results, which met the requirements of the construction of vector elements and proved that the recombinant vector was successfully constructed. Conclusions Based on the above results, this study proves that the recombinant shuttle vector with two spore-producing-dependent promoters can be successfully constructed by in-fusion cloning technology, laying the foundation for the construction of engineered Bacillus thuringiensis expressing dsRNA of AaCPR100A.

Aim To investigate the role of miR-125 b and its DNA methylation in homocysteine ( Hcy )-in-duced vascular smooth muscle cells( VSMCs) prolifera-tion. Methods VSMCs were stimulated with 0,50, 100, 200, 500 μmol · L-1 Hcy respectively. Then qRT-PCR was used to detect the mRNA levels of miR-125b,and nested-touchdown methylation-specific PCR ( ntMS-PCR) was used to detect the methylation levels of miR-125b. VSMCs were transfected with miR-125b precursor or the inhibitor of miR-125b ,then 3-(4,5-dimethylthiazol-2-yl)-2-5-diphenyl tetrazolium bromide ( MTT ) assay was used to reflect the proliferation of VSMCs. The distribution of CpG islands of miR-125b promoter region was analyzed by bioinformatics meth-ods. VSMCs were stimulated with 100 μmol·L-1 Hcy and transfected with or without DNA methylation inhib-itors 5-nitrogen impurity cytidine ( AZC) , then the ex-pression of miR-125b was detected by qRT-PCR. Re-sults The mRNA levels of miR-125 b were decreased in 100,200,500 μmol·L-1 Hcy group compared with 0 μmol·L-1 Hcy group. The precursor of miR-125b could inhibit the proliferation activity and the inhibitor of miR-125 b could increase the proliferation activity of VSMCs cells. Bioinformatics analysis indicated that MiR-125 b promoter region had a CpG island whose length was 792 bp ( 1881-2672 ) . The miR-125 b pro-moter region methylation levels increased after Hcy in-tervention ( P <0. 01 ) . The expression level of miR-125 b increased after AZC intervention ( P <0. 05 ) . Conclusions ① Hcy promotes vascular smooth mus-cle cell proliferation maybe by down-regulating the ex-pression of miR-125b. ② Hcy down-regulates the ex-pression of miR-125 maybe by up-regulating the methy-lation levels of miR-125b promoter region.

Aim To explore the role of ERO1 αand its DNA methylation in homocysteine (Hcy)-induced in-hibition of hepatocytes proliferation.Methods The hepatocytes stimulated with 0 μmol·L -1 Hcy were set as the normal group (NC group)and the hepatocytes stimulated with 1 00 μmol·L -1 Hcy as the experimen-tal group (Hcy group).Methyl thiazolyl tetrazolium (MTT)reduction assay was used to reflect the prolifer-ation of the hepatocytes;qRT-PCR and Western blot were used to detect the mRNA and protein levels of ERO1 α;the expression of green fluorescence protein was observed in hepatocytes after the recombinant plas-mid of ERO1 α was constructed,which was used to confirm if the recombinant plasmid into hepatocytes was successful,then the mRNA and protein levels of ERO1 αwere assayed and the proliferation of the hepa-tocytes was also detected;ntMSP was used to detect the change of ERO1 αDNA methylation.Results The mRNA and protein levels of ERO1 αwere decreased in Hcy group compared with NC group,and the prolifera-tion activity of hepatocytes in Hcy group was de-creased.Sequencing result showed that the recombi-nant plasmid of ERO1 αwas constructed successfully. QRT-PCR and Western blot revealed that ERO1 αwas overexpressed. The result of MTT suggested that ERO1 αoverexpression restored hepatocyte proliferation inhibited by Hcy.Hcy caused ERO1 αDNA hyperm-ethylation.Conclusions Hcy inhibits hepatocyte pro-liferation by downregulating the expression of ERO1 α, and methylation of ERO1 αpromoter may play a role in this process.

Aim To investigate the possible mecha-nisms of the levels of NO decrease induced apoptosis in human placental trophoblast cells. Methods Human placental trophoblast cells ( HTR-8 ) were cultured in 5 ml DMEM-F12 culture medium with 37℃ 5% CO2 . Then, the old culture medium was discarded and re-placed with 10,100,500,1 000 μmol·L-1 L-NAME, and the group without L-NAME was set as the control group, cultured for 48h. The effects of L-NAME on the survival of cells were detected by methylthiazolyldiphe-nyl tetrazolium bromide ( MTT); the content of NO in cells was tested by nitrate reductive enzymatic;trans-mission electron microscopy, flow cytometry analysis and Annexin-V FITC dyeing were used to test the effects of L-NAME on apoptosis in HTR-8 cells;restore Fe3+ colorimetric assay was applied for detection of to-tal antioxidant capacity ( T-AOC ) , xanthine oxidase for detection of superoxide dismutase ( SOD) activity, and thiobarbituric acid colorimetry for determination of content of MDA. Results Compared with the control group, the survival rate of HTR-8 cells and the levels of NO in 100,500,1 000 μmol·L-1 L-NAME group were significantly reduced(P<0.05,P<0.01). Flow analysis and Annexin-V FITC staining showed that L-NAME could induce cell apoptosis in a dose-dependent manner. The number of cell apoptosis was negatively correlated with the content of NO ( r = -0.5210 ) in HTR-8 cells. Transmission electron microscopy results showed that compared with the control group, the ex-perimental group's cell nucleus shape was irregular, nuclear pyknosis in irregular shape, the chromatin ag-glutination or side the collection, mitochondrial swell-ing or enrichment, crest fracture or dissolved, even vanished, forming the vacuole, especially in 100 μmol ·L-1 L-NAME group, the apoptotic bodies obviously appeared. At the same time, T-AOC, SOD levels in HTR-8 cells decreased ( P <0.05 ) , and the MDA content increased ( P<0.05 ) . The number of cell ap-optosis was negatively correlated with the level of T-AOC ( r= -0.3212 ) , SOD ( r= -0.2779 ) in HTR-8 cells , while positively correlated with the content of MDA(r=0.2807). Conclusion Oxidative stress may play an important role in the levels of NO decrease in-duced apoptosis in human placental trophoblast cells.