[Identification and Expression of the yellow Gene Family in Aedes aegypti].

Objective: To identify the yellow family genes in Aedes aegypti and analyze the gene structure, phylogenetic evolution and their expression at various developmental stages and in different tissues. Methods: The yellow gene family was identified in Ae. aegypti by blasting the Ae. aegypti genome database with the amino acid sequence of the MRJP domain of Dm-yellow gene of Drosophila melanogaster（GenBank No. AAF45497）. The physico-chemical property and domains were analyzed with the on-line ExPaSy software. The signal peptide was predicted using SignalP4.1 software. Sequence alignment and the phylogenetic tree were made through combined use of DNAstar, MEGA6.0 and GeneDoc. Total RNA was extracted from Ae. aegypti, cDNA was generated, and expression of the yellow family genes at various developmental stages （egg, first to fourth instar, pupa, non-blood-fed female and male mosquitoes） and in different tissues （salivary gland, midgut, fat body, and ovary） was quantified using qRT-PCR. Results: Twelve yellow genes were identified from Ae. aegypti genome: Aa-yellow, Aa-yellow-b, Aa-yellow-c, Aa-yellow-d, Aa-yellow-e, Aa-yellow-f2, Aa-yellow-fb, Aa-yellow-fc, Aa-yellow-g, Aa-yellow-g2, Aa-yellow-h, and Aa-yellow-x. Bioinformatics demonstrated that all covered the MRJP domain and a signal peptide sequence. Sequence alignment revealed low （15%-49%） homology among the proteins, but high homology（60%） in the conserved domain. According to the phylogenetic tree analysis, the encoded 12 YELLOW proteins were classified into 5 subfamilies, and 11 had orthologues in D. melanogaster. qRT-PCR revealed high expression of Aa-yellow-d （0.018 9） and Aa-yellow-x （0.023 5） in male Ae. aegypti （P<0.01 or P<0.05）; high expression of Aa-yellow-fc （0.024 8, 0.034 9） in female Ae. aegypti and in the salivary gland （P<0.01）; high expression of Aa-yellow-f2 （0.093 4） in the second instar stage （P<0.01）; high expression of Aa-yellow （0.562 1）, Aa-yellow-e （0.004 4）, and Aa-yellow-fb （0.008 4） in the third instar stage （P<0.05）; and high expression of Aa-yellow （0.569 4）, Aa-yellow-e （0.027 0）, Aa-yellow-f2 （0.006 5）, Aa-yellow-fb （0.001 0）, Aa-yellow-h （0.084 8） and Aa-yellow-x （0.015 1） in the ovary. Genes other than Aa-yellow-c （0.004 0） and Aa-yellow-x （0.007 4） were hardly expressed in the midgut. Conclusion: The 12 yellow genes identified in the Ae. aegypti genome have low homology, and are differentially expressed at different developmental stages and in tissues.

[Recombinant plasmid constructed and cytotoxicity studied for outer membrane protein LipL32 gene of Leptospira strain 017].

OBJECTIVE: To construct the recombinant plasmid containing the outer membrane protein LipL32 gene of Leptospira strain 017 and to study on the cytotoxicity of the expression protein. METHODS: By the polymerase chain reaction (PCR), the LipL32 gene was amplified from Leptospira strain 017 genome and cloned into pET32a(+) with enzyme digestion, then used to transform E. coli JM109. After induced with IPTG, the target protein was expressed and used to immunize New zealand white rabbit. Western Blotting identified the immunogenicity of the expressed protein. Then the purified and renatured protein was acted on ECV304 cell so as to get its cytotoxicity detected by examining the LDH and NO (nitrogen monoxide) release from cell. RESULTS: The full length of the LipL32 gene about 816 bp was obtained by PCR. The recombinant plasmid was identified by enzyme digestion, PCR and DNA sequencing. After induced with IPTG, the expressed protein existed mainly in the form of inclusion bodies about 52 x 10(3) (relative molecular mass) which was consistent with the expected size of the fused protein. After rabbit immunity, the titre of the produced multiclonal antibody reached 1 : 32 000 measured by ELISA. Western Blotting analysis found a positive band specifically in the target protein position. The release of the LDH and NO of the ECV304 cell treated with LipL32 had significant increase compared with the control group. CONCLUSION: The recombinant plasmid containing LipL32 gene is successfully constructed and can express the target protein in E. coli JM109. The expressed target protein has cytotoxicity.

[RelE toxin protein of Mycobacterium tuberculosis induces growth inhibition of lung cancer A-549 cell].

OBJECTIVE: To investigate whether the RelE toxin protein of mycobacterium tuberculosis has a growth inhibition effect on lung cancer A-549 cell. METHODS: The complete open-reading frame sequences of RelE, RelB and RelBE genes were amplified by PCR with using M. tuberculosis H37Rv genomic DNA as the template. The RelE, RelB and RelBE genes were subcloned into PcDNA3. 1 (+). After being verified with restriction endonuclease digestion and DNA sequence determination, the recombinant vectors were applied to transfect lung cancer A-549 cells by liposome transfection method. By determining the growth curve and protein level of living cells, MTT cell proliferation assay, the apoptosis of cells with HE staining and the apoptosis rate of transient transfection cells detected by Flow Microfluorimetry, it was observed and analyzed whether the RelE toxin protein of mycobacterium tuberculosis had a growth inhibition and apoptosis effects on lung cancer A-549 cell. RESULTS: The cell proliferation rate of lung cancer A-549 cells effected by the RelE toxin protein of mycobacterium tuberculosis was lower than that of the other groups, and this group cells with RelE protein effect showed more sensitive to nutrition starving. HE staining revealed that this group cells which included the transient transfection with RelE expression plasmid appeared to have more apoptosis cells and higher apoptotic rate than other groups did (P < 0.05). CONCLUSION: The RelE toxin protein of mycobacterium tuberculosis has growth inhibition and apoptotic effect on lung cancer A-549 cell.

[Construction of the eukaryotic recombinant vector and expression of the outer membrane protein LipL32 gene from Leptospira serovar Lai].

AIM: To construct the eukaryotic experssion vector of LipL32 gene from Leptospira serovar Lai and express the recombinant plasmid in COS-7 cell. METHODS: The LipL32 gene was amplified from Leptospira strain 017 genomic DNA by PCR and cloned into pcDNA3.1, through restriction nuclease enzyme digestion. Then the recombinant plasmid was transformed into E.coli DH5alpha. After identified by nuclease digestion, PCR and sequencing analysis, the recombinant vector was transfected into COS-7 cell with lipsome. The expression of the target gene was detected by RT-PCR and Western blot. RESULTS: The eukaryotic experssion vector pcDNA3.1-LipL32 was successfully constructed and stably expressed in COS-7 cell. CONCLUSION: The eukaryotic recombinant vector of outer membrane protein LipL32 gene from Leptospira serovar Lai can be expressed in mammalian cell, which provides an experimental basis for the application of the Leptospira DNA vaccine.

[Protein-protein interaction between hypothetical protein Rv1246c and Rv1247c of Mycobacterium tuberculosis].

OBJECTIVE: To investigate the protein-protein interaction between hypothetical protein Rv1246c and Rv1247c of Mycobacterium tuberculosis. METHODS: By PCR technique, the complete open-reading frame sequences of Rv1246c and Rv1247c gene were amplified from the M. tuberculosis H37Rv genomic DNA as template. The PCR-amplified cDNAs of Rv1247c and Rv1246c gene were subcloned into pGBKT7 and pGADT7-Rec vector respectively for constructing recombinant plasmids pGBKT7-Rv1247c and pGADT7-Rv1246c. After verified by restriction endonuclease digestion and DNA sequence determination, the recombinant vectors were used to transform the yeast cell AH109 by lithium acetate method. RESULTS: The yeast cells co-transformed with pGBKT7-Rv1247c and pGADT7-Rv1246c grew on SD/-Ade/-His/-Leu/-Trp plates, and the beta-galactosidase activity assays showed the positive signal. CONCLUSION: The hypothetical protein Rv1246c and Rv1247c could interact with each other in yeast cells.

[Effect of transfected Rv0901 gene on the activity of mice macrophages].

OBJECTIVE: To test the effect of Rv0901 gene of Mycobacterium tuberculosis on the activity of mice macrophages. METHODS: Peritoneal macrophages of mice were isolated and transfected with pcDNA3. 1 or pcDNA3. 1-Rv0901 plasmid DNA, along with the GFP DNA. The effectiveness of the transfection was detected by RT-PCR. The expression of the GFP and the apoptosis ratio of the macrophages were detected by FCM 72 hours after the transfection. The level of nitric oxide and IFN-gamma in cultural supernatant were also measured 72 hours after transfection. RESULTS: All of the macrophages being transfected had the expression of GFP. After being transfected with pcDNA3. 1-Rv0901, the 528 bp gene of Rv0901 was amplified by RT-PCR. The macrophages transfected with pcDNA3. 1-Rv0901 had higher apoptosis ratio [(56.4 +/- 2.0)% vs (19.9 +/- 1.5)%] and released more nitric oxide [(40.4 +/- 3.0) micromol/L vs (27.5 +/- 3.2) micromol/L] and IFN-gamma [(2.11 +/- 0.031) ng/mL vs (0.62 +/- 0.025) ng/mL] in the cultural supernatants than those transfected with pcDNA3. 1 (P < 0.05). CONCLUSION: Transient transfection of pcDNA3. 1-Rv0901 increases the apoptosis ratio of the macrophages, which could increase the release of nitric oxide and IFN-gamma.

[Molecular cloning and expression of hypothetical proteins Rv1494 and Rv1495 of M.tuberculosis H37Rv strain].

OBJECTIVE: The mechanism by which M.tuberculosis persists and survives in host macrophage is not fully understood, however, the M. tuberculosis chromosome-encoded TA loci perform functions possibly of signaling to these processes. To explore the biological functions of M. tuberculosis chromosome-encoded TA loci, the Rv1494 and Rv1495 genes of M.tuberculosis H37Rv strain were cloned and expressed. METHODS: The hypothetical proteins Rv1494 and Rv1495 were bioinformatically analyzed by means of Bioedit software, Dnaman software and Pfam database. The complete open-reading frame sequences of Rv1494 and Rv1495 genes were amplified by PCR using M.tuberculosis H37Rv genomic DNA as the template, and the PCR products were cloned into prokaryotic expression vector pET32a(+), respectively. After induction of expressions in E.coli host strain BL21 (DE3), the recombinant proteins were purified and detected by Western blotting. RESULTS: According to bioinformatic analysis, the hypothetical proteins of Rv1494 and Rv1495 genes shared some homologies with mazEF family, one of E. coli chromosomal TA loci (homology at 26% and 29.5%). Sequence analysis showed that the inserted target genes and its reading frames were completely correct. The recombinant plasmids were induced with IPTG to effectively express the fusion proteins with relative molecular mass coincident with prediction. The specific positive signals were identified from the immunoblots. CONCLUSION: For the first time, the Rv1494 and Rv1495 genes of M.tuberculosis H37Rv strain were cloned and its prokaryotic expression vectors were constructed successfully in this experiment, which may facilitate further functional study of this mazEF-like gene pair.