High throughput screening of pure silica zeolites for CF4 capture from electronics industry gas.

The capture and separation of CF4 from CF4/N2 mixture gas is a crucial issue in the electronics industry, as CF4 is a commonly used etching gas and the ratio of CF4 to N2 directly affects process efficiency. Utilizing high-throughput computational screening techniques and grand canonical Monte Carlo (GCMC) simulations, we comprehensively screened and assessed 247 types of pure silicon zeolite materials to determine their adsorption and separation performance for CF4/N2 mixtures. Based on screening, the relationships between the structural parameters and adsorption and separation properties were meticulously investigated. Four indicators including adsorption selectivity, working capacity, adsorbent performance score (APS), and regenerability (R%) were used to evaluate the performance of adsorbents. Based on the evaluation, we selected the top three best-performing zeolite structures for vacuum swing adsorption (LEV, AWW and ESV) and pressure swing adsorption (AVL, ZON, and ERI) processes respectively. Also, we studied the preferable adsorption sites of CF4 and N2 in the selected zeolite structures through centroid density distributions at the molecule level. We expect the study may provide some valuable guidance for subsequent experimental investigations on adsorption and separation of CF4/N2.

Dynamic structural insights into the molecular mechanism of DNA unwinding by the bacteriophage T7 helicase.

The hexametric T7 helicase (gp4) adopts a spiral lock-washer form and encircles a coil-like DNA (tracking) strand with two nucleotides bound to each subunit. However, the chemo-mechanical coupling mechanism in unwinding has yet to be elucidated. Here, we utilized nanotensioner-enhanced Förster resonance energy transfer with one nucleotide precision to investigate gp4-induced unwinding of DNA that contains an abasic lesion. We observed that the DNA unwinding activity of gp4 is hindered but not completely blocked by abasic lesions. Gp4 moves back and forth repeatedly when it encounters an abasic lesion, whereas it steps back only occasionally when it unwinds normal DNA. We further observed that gp4 translocates on the tracking strand in step sizes of one to four nucleotides. We propose that a hypothetical intermediate conformation of the gp4-DNA complex during DNA unwinding can help explain how gp4 molecules pass lesions, providing insights into the unwinding dynamics of gp4.

Long Noncoding RNA CRNDE Promotes Proliferation of Gastric Cancer Cells by Targeting miR-145.

BACKGROUND/AIMS: The colorectal neoplasia differentially expressed (CRNDE) gene is a long noncoding RNA (lncRNAs) that is upregulated in colorectal cancer and glioma. Here, we investigated the regulatory function of CRNDE in gastric cancer (GC). METHODS: CRNDE and miR-145 expression were assayed by qRT-PCR, and E2F3 protein expression was measured by western blotting. A luciferase reporter assay was used to detect the direct regulation of miR-145 by CRNDE. Cell viability and colony formation of human GC cells were detected using MTT and colony formation assay, respectively. RESULTS: CRNDE was highly expressed in GC cell lines and tissues; overexpression of CRNDE increased GC cell viability and promoted colony formation. Knockdown of CRNDE did not result in loss of expression-related effects on cell proliferation and colony formation. Further investigation revealed that the miR-145 target gene E2F3 was strongly expressed following CRNDE competitive molecular sponging of miR-145. CONCLUSION: CRNDE acted as a growth-promoting lncRNA in GC and maybe a potential target of GC treatment.

JMJD2A predicts prognosis and regulates cell growth in human gastric cancer.

A number of JmjC domain-containing histone demethylases have been identified and biochemically characterized in mammalian. JMJD2A is a transcriptional cofactor and enzyme that catalyzes demethylation of histone H3 lysines 9 and 36. Here in this study, we aim to explore the role of JMJD2A in human gastric cancer. Quantitative real-time PCR, Western blot and immunohistochemistry analyses reveal higher expression of JMJD2A in clinical gastric cancer tissues than that in normal gastric mucosa. JMJD2A expression is associated with tumor stage and nodal status, and high level of JMJD2A predicts poor overall and disease-free survival. Univariate and multivariate survival analyses demonstrate that JMJD2A could serve as an independent prognostic factor. Furthermore, we show that inhibition the expression of JMJD2A attenuates the growth and transformation of three lines of gastric cancer cells. Mechanically, JMJD2A knockdown induces apoptosis of gastric cancer cells by up-regulating the expression of pro-apoptotic proteins and by down-regulating anti-apoptotic protein. Finally, we show that JMJD2A level is correlated with the level of the pro-apoptotic microRNA miR-34a in gastric cancer tissues and JMJD2A represses the expression of miR-34a by decreasing its promoter activity. Those findings demonstrate that JMJD2A regulates gastric cancer growth and serves as an independent prognostic factor, and implicate that JMJD2A may be a promising target for intervention.

The RNA-binding protein PCBP2 facilitates gastric carcinoma growth by targeting miR-34a.

Gastric carcinoma is the fourth most common cancer worldwide, with a high rate of death and low 5-year survival rate. However, the mechanism underling gastric cancer is still not fully understood. Here in the present study, we identify the RNA-binding protein PCBP2 as an oncogenic protein in human gastric carcinoma. Our results show that PCBP2 is up-regulated in human gastric cancer tissues compared to adjacent normal tissues, and that high level of PCBP2 predicts poor overall and disease-free survival. Knockdown of PCBP2 in gastric cancer cells inhibits cell proliferation and colony formation in vitro, whereas opposing results are obtained when PCBP2 is overexpressed. Our in vivo subcutaneous xenograft results also show that PCBP2 can critically regulate gastric cancer cell growth. In addition, we find that PCBP2-depletion induces apoptosis in gastric cancer cells via up-regulating expression of pro-apoptotic proteins and down-regulating anti-apoptotic proteins. Mechanically, we identify that miR-34a as a target of PCBP2, and that miR-34a is critically essential for the function of PCBP2. In summary, PCBP2 promotes gastric carcinoma development by regulating the level of miR-34a.

[Responses of radial growth of Quercus mongolica to stand density and climatic factors in a mountainous area of eastern Liaoning Province, China]. / è¾½ä¸œå±±åŒºè’™å¤æ Žå¾„å‘ç”Ÿé•¿å¯¹æž—åˆ†å¯†åº¦å’Œæ°”å€™å› å­çš„å“åº”.

To explore the effects of stand density and climatic factors on radial growth of Quercus mongolica, we used tree ring chronology to examine the radial growth changes in a secondary Q. mongolica forest under different levels of stand density (thinning). The meteorological data combined with the driving factors of Q. mongolica growth were analyzed. The results showed that the radial growth of Q. mongolica was significantly affected by stand density. The mean annual radial growth of Q. mongolica was 3.12 mm in low-density virgin forest, 1.55 and 1.42 mm in the two medium-density secondary forests, respectively, and 0.96 mm in high-density secondary forest. The thinning intensity of 20% had a limited effect on promoting the radial growth recovery of high-density forest (1900 trees·hm-2), but had a significant effect on medium-density forest (1600 trees·hm-2). The radial growth of Q. mongolica was sensitive to the precipitation changes in January and February of the current year. Thinning reduced the sensitivity of Q. mongolica radial growth to climate. Under scenarios of climate warming and drying, density regulation could be beneficial in mitigating the adverse effects of climate change on the growth of Q. mongolica.

[Advances on olfactory receptor gene].

The olfactory sense plays a key role in animals'life time. The main gene related with olfaction was olfactory receptor (OR) gene. This review introduced the structure, expression regulation, distribution, molecular evolution and polymorphism of OR gene. The relationship between OR gene and olfactory function and olfactory deficits was also discussed.

Rv0901 from Mycobacterium tuberculosis, a possible novel virulent gene proved through the recombinant Mycobacterium smegmatis.

The function of protein-coding gene Rv0901 of Mycobacterium tuberculosis, which belongs to the cell wall and cell processes category, is not yet clear. To explore its features, we amplified this gene from the H37Rv genome, and His-tagged Rv0901 protein was expressed and purified. Also, a recombinant plasmid bearing Rv0901 was constructed and electroporated into a virulent Mycobacterium smegmatis, using shuttle expression vector pMV261. Transformants were induced to express a predicted protein of Rv0901, identified by SDS-PAGE. Rv0901 protein and recombinant M. smegmatis were used to expose mammalian cells. In addition we studied the effect of protein or recombinant M. smegmatis on cells and in animals with regard to survival ratio, apoptosis ratio, quantum of nitric oxide, and gamma interferon. Together, gene function, protein function, and animal test results suggest that Rv0901 has some relationship with the virulence and immunogenicity of M. tuberculosis.

[Spatial structure characteristics of the main tree species in a mixed broadleaved Korean pine (Pinus koraiensis)forest in a mountainous area of eastern Liaoning Province, China]. / è¾½ä¸œå±±åŒºåŽŸå§‹é˜”å¶çº¢æ¾æž—ä¸»è¦æ ‘ç§ç©ºé—´ç»“æž„ç‰¹å¾.

Maintaining forest structural diversity is generally considered as an effective way to preserve forest stability and biodiversity. The spatial structure characteristics of the dominant tree species in a climax community were investigated in a primary mixed broadleaved Korean pine (Pinus koraiensis) forest in a mountainous area of eastern Liaoning. Stand spatial structure parameters were determined based on the relationships among neighboring trees. The climax communities were used as a theoretical reference for optimizing the spatial structure of a low-quality secondary forest and monoculture plantation. The diameter distribution of the trees in the pine forest exhibited an inverse J-shape, indicating that understory regeneration was relatively good and with certain proportion of large-diameter trees. The main tree species were randomly distributed across the whole plot (=0.507) and in an intensively mixed state (=0.82). An average DBH comparison of trees in the stand indicated that they were at a intermediate status (=0.506). There was a differentiation among different dominances along the high intensity mixed dimension in the stand, indicating an optimal distribution of understory trees and the rational utilization of resources. Trees in the small diameter category were at a state of complete compression, while canopy trees were at a state of complete dominance in terms of their vertical space. Individuals of each dominant tree species were randomly scattered, with a random pattern of individuals throughout the climax community.

[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.

[Expression and identification of gene Loa22 from the virulent strain of serovar Lai of L. interrogans and its cytotoxicity to macrophages].

OBJECTIVE: To study the function of Loa22 gene from virulent serovar Lai. L. interrogans by expressing its protein. METHODS: The recombinant plasmid with Loa22 was constructed and its expression was induced by IPTG. The expression product was identified by SDS-PAGE and Western Blotting and purified with GST-affinity chromatography. The purified protein was applied to mice macrophages ANA-1 cells purified by GST-affinity column and exerted to ANA-1 cells. The cytotoxicity of purified protein to ANA-1 was evaluated by detecting LDH activity in culture medium, XTT aborbtion and apoptosis ration. RESULTS: The recombinant plasmid with Loa22 mature peptide was constructed successfully and the protein was purified subsequently. Significant higher level of LDH activity and apoptosis ratio and lower XTT absorption were observed by comparison of expression protein treated cells and those untreated. CONCLUSION: Loa22 had a toxic effect on ANA-1 and the gene Loa22 might be a virulent-related gene of L. interrogans.

[Construction and screen of recombinant BCG strain expressing and secreting human interleukin 12 protein].

OBJECTIVE: To screen and construct the recombinant Bacillus Calmette-Guerin (rBCG) strain expressing and secreting the human interleukin 12 (rBCG-12). METHODS: IL-12 complete gene including p40 and p35 subunits was amplified by PCR from a plasmid pORF-h IL-12 and cloned into E. coli-Mycobacteria shuttle vector pMV361. The recombinant vector was named as rpMV-IL-12. rpMV-IL-12 was confirmed by DNA sequencing, and then rpMV-IL-12 was used, by electroporation way, to transform the BCG for getting the recombinant rBCG-12 strain. The positive rBCG-12 clone was screened and identified by kanamycin resistance and IL-12 target gene PCR amplification. The IL-12 protein expression of rBCG-12 was induced with heat shock reaction. Then rBCG-12 culture supernatant and bacterial precipitation were collected respectively and analyzed with SDS-PAGE electrophoresis for their protein components. RESULTS: The recombinant shuttle plasmid rpMV-IL-12 was constructed successfully. The sequence of amplified IL-12 gene was consistent with GenBank report. By SDS-PAGE electrophoresis, it was confirmed that the IL-12 protein could express and secrete into the supernatant of rBCG-12 strain culture. CONCLUSION: The recombinant BCG strain expressing human IL-12 protein, rBCG-12 strain, is constructed and screened successfully. It is the foundation for further research on rBCG-12 immune function.

[Construction of recombinant E. coli-L. interrogans shuttle plasmid pGKINVA and screening recombinant leptospira strains].

OBJECTIVE: To further investigate pathogenic function of invA in Leptospira, recombinant L. biflexa-Escherichia coli shuttle vector pGKINVA was constructed, and electropored into L. biflexa strain Patoc I . METHODS: The invA gene was cloned into shuttle vector pGKble24 to construct a recombinant L. biflexa-Escherichia coli shuttle vector pGKINVA. The recombinant vectors were electropored into L. biflexa serovar Patoc strain Patoc I . RESULTS: A 558 bp invA was amplified from L. interrogans serovars Lai strain 017 and ligated with Aat II and Xma I digested pGKble24. After screening by kanamycin and blue/white color, the recombinant pGKINVA was obtained and sequenced. Subsequently, the recombinant pGKINVA was electropored into L. biflexa strain Patoc I. The selected mutants were identified by PCR. CONCLUSION: Recombinant L. biflexa-Escherichia coli shuttle vector with invA insert was constructed and two strains of pGKINVA transformed Leptospira were obtained. These pGKINVA transformed Leptospira strains would provid an experimental model to investigate potential pathogenic functions of invA in vivo.

[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.

[Effects of Tongxinluo and Simvastatin on the stabilization of vulnerable atherosclerotic plaques of aorta in aortic atherosclerosis and molecular mechanism thereof: a comparative study with rabbits].

OBJECTIVE: To evaluate the plaque stabilization effects of Tongxinluo and Simvastatin in aortic atherosclerosis, and to explore molecular mechanism. METHODS: Twenty-three New Zealand white rabbits underwent aortic balloon injury and fed with high-cholesterol diet for 16 weeks and then randomly divided into 3 groups: Tongxinluo group (n = 6, undergoing gastric perfusion of Tongxinluo 1 gxkg(-1)xd(-1)), simvastatin group (n = 9, undergoing gastric perfusion of simvastatin 2 mgxkg(-1)xd(-1)), and model group (n = 8, without drug administration). Another 6 rabbits were used as normal controls. Peripheral blood samples were collected 10 weeks before the administration, and 3 and 16 weeks after the administration to detect the levels of total cholesterol (TG), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), and by the end of experiment peripheral blood samples were collected to detect the levels of serum endothelin (ET) and nitric oxide (NO). Then the rabbits were killed and their aortas were taken out to undergo pathological examination. Western blotting was used to detect the protein expression of Metalloproteinase (MMP)-1 and cyclooxygenase (COX)-2 and RT-PCR was used to detect the mRNA expression of FasL and bcl-2. RESULTS: By the end of the experiment the levels of blood lipids were raised by 1 approximately 2 times in the normal group (P < 0.05), and raised more significantly in the model and intervention groups (P < 0.05 approximately 0.01), especially the TC level of the model group was raised by 40 tomes. The levels of blood lipids of the simvastatin group were significantly lower than those of the model group (P < 0.05 approximately 0.01), however, between the Tongxinluo and model groups there were no significant differences in the levels of blood lipids. In the model group the blood level of ET was raised significantly and the level of NO was significantly decreased (both P < 0.01). The ET levels of the 2 intervention groups were both significantly lower than that of the model group (both P < 0.01), and the NO levels of the 2 intervention groups were both significantly higher than those of the normal group (P < 0.01 approximately 0.05), however, there were no significant differences in the ET and NO levels between these 2 intervention groups (all P > 0.05). Sclerotic plaques were distributed intensely at high degrees in the model group. The sclerotic changes of the 2 intervention groups were significantly milder. The contents of collagen of the 2 intervention groups were 0.11 +/- 0.08 and 0.22 +/- 0.11 respectively, both significantly higher then that of the model group (0.01 +/- 0.01, both P < 0.05). The intima/media ratios of aorta of the 2 intervention groups were 0.25 +/- 0.13 and 0.28 +/- 0.12 respectively, both significantly lower than that of the model group (0.60 +/- 0.37). The macrophage amount in the plaque (RAM-11 positively stained area) of the 2 intervention groups were 0.11 +/- 0.10 and 0.06 +/- 0.43 respectively, both significantly lower than that of the model group (0.24 +/- 0.14). The levels of protein expression of MMP-1 and COX-2 in the atherosclerotic lesions of the model group were both significantly higher than those of the normal group and the MMP-1 and COX-2 protein expression levels of the 2 intervention groups were all significantly lower than those of the model group (P < 0.05 approximately 0.01), however, there were no significant differences between these 2 groups (both P > 0.05). Significant linear correlation existed in the MMP-1 and COX-2 positively stained areas (r = 0.533, P = 0.007) and protein expression level (r = 0.833, P < 0.01). Compared with the normal group, the mRNA expression level of FasL in the aorta tissue of the model group was significantly higher (2.44 +/- 0.44) and the mRNA expression level of bcl was significantly lower (0.17 +/- 0.11). Compared with the model group, the mRNA expression levels of FasL of the 2 intervention groups were 0.47 +/- 0.36 and 1.32 +/- 0.61 respectively, both significantly lower and the mRNA expression levels of bcl were 0.64 +/- 0.16 and 1.66 +/- 0.94 respectively, both significantly higher (all P < 0.05 approximately 0.01), with the FasL mRNA expression of the Tongxinluo group significantly higher than that of the simvastatin group (P < 0.05). CONCLUSION: Tongxinluo and simvastatin have the same effects of stabilizing the vulnerable plaques, and the mechanism may be related with inhibition of expression of COX-2 and MMP and reduction of the apoptosis in the atherosclerotic plaque.

[Beneficial effects of carvedilol on cardiomyocyte apoptosis and bcl-2/bax expression after acute myocardial infarction an experiment with rats].

OBJECTIVE: To investigate the beneficial effects of carvedilol on cardiomyocyte apoptosis and related gene expression after acute myocardial infarction (AMI). METHODS: Eighty-three female SD rats underwent ligation of left anterior descending coronary artery, and were randomly assigned to 2 groups 24 hours later: carvedilol (n = 40, 10 mg.kg(-1).d(-1)was administered via direct gastric gavage 24 hs after the ligation, Group C) and AMI control group (n = 43, normal saline of the same volume was given by gastric gavage, Group MI). Another 27 rats were used as sham operation group (Group S, administered with normal saline too). The rats of each group were killed and their hearts were taken out 48 hours and 4 weeks after observation respectively (MI-48 h, MI-4 week, C-48 h, C-4 week, S-48 h, and S-4 week subgroups). TUNEL and DNA gel electrophoresis were used to detect the cardiomyocyte apoptosis. Immunohistochemistry and Western blotting were used to detect the expression of bcl-2 and bax. RESULTS: The apoptotic indices of the infracted/scar, border and non-infarcted areas at any time-point of Group MI were all significantly higher than those of Group S (all P < 0.05). Only the apoptotic indices of the infracted/scar and border areas of the C-4 week subgroup were significantly lower than those of the MI-4 week subgroup (both P < 0.05), and were close to those of the non-infarcted area. DNA gel electrophoresis showed that the positive rate of Group S at any time-point were both 0, the positive rate of MI-48 h subgroup and C-48 h subgroup were both significantly higher than that of Group S (both P < 0.05) without significant difference between these 2 groups, and the positive rates of the MI-4 week subgroup and C-4 week subgroup were both 0. Immunohistochemistry showed that the bax gene expression was slightly to significantly increased in the infarcted/scar, border, and non-infarcted areas of the MI-48 h and MI-4 week subgroups. The bcl-2 expression was significantly increased only in the infracted area of the MI-48 h subgroup. The bcl-2 expression was slightly increased in the infracted and border areas of the C-48 h subgroup and the bax expression was significantly decreased in the infracted/scar area of the C-4 week subgroup. Western blotting showed that (1) the bcl-2 expression of the S-4 week subgroup was significantly higher than that of the S-48 h subgroup (P < 0.05), (2) the bcl-2 expression and bax expression of the MI-48 h subgroup were significantly higher than that of the S-48 h subgroup (P < 0.05 - 0.01), the bcl-2/bax ratio of the MI-48 h subgroup was significantly lower that that of the S-48 h subgroup, however, there were no significant differences in the bcl-2 and bax expression and bcl-2/bax ratio between the MI-4 week subgroup and S-48 h subgroup (all P > 0.05), and (3) There were no significant difference in the bcl-2 and bax expression between Group A and Group S (all P > 0.05), however, the bcl-2/bax ratios at the 2 time-points of Group C were both significantly higher than those of Group MI. CONCLUSION: Cardiomyocyte apoptosis occurs in the infarction/scar, border and non-infarcted areas after AMI. Prolonged treatment with carvedilol reduces cardiomyocyte apoptosis in the scar and border areas and increases the expression ratio of bcl-2/bax.

[Prokaryotic expression and characterization of the Rv2994 gene from Mycobacterium tuberculosis].

OBJECTIVE: To construct a prokaryotic expression vector bearing Rv2994 gene from Mycobacterium tuberculosis and provide materials for investigating the function of the gene. METHODS: The Rv2994 gene was amplified by Polymerase Chain Reaction from Mycobacterium tuberculosis H37Rv strain and cloned into prokaryotic expression vector pGEX-1lamdaXT. The recombinant plasmid pGEX-2994 was sequenced and transformed into E. coli JM109 to be induced with IPTG and expressed the 73kDa fusion protein GST-Rv2994. It's antigenicity was confirmed by Western blotting. The expression product was purified and immunized the new Zealand rabbits. RESULTS: The Rv2994 gene was amplified accurately from the genome DNA of H37Rv. A recombinant fused expression vector pGEX-Rv2994 was constructed and GST-Rv2994 protein was purifiel to immunize New Zealand rabbit. CONCLUSION: The prokaryotic expression vector pGEX-2994 was constructed, and the 73kDa fusion protein GST-Rv2994 was expressed and purified successfully. It provided the basis for the further study of the Rv2994 gene.

[Expression of the fusion protein CFP10-ESAT6 of Mycobacterium tuberculosis and the study of its immunogenicity].

OBJECTIVE: To express a recombinant fusion protein CFP10-ESAT6 of Mycobacterium tuberculosis, and obtain the polyclonal antibodies of this fusion protein by immune rabbit. METHODS: The 630 bp cfpl0-esat6 fusion gene fragments were amplified from the genomic DNA of a Mycobacterium tuberculosis reference strain H37Rv and inserted into the expression plasmid pET32a (+) to generate the recombinant plasmid pET-cfp10-esat6. The recombinat expression plasmid was transformed into E. coli BL21 (DE3). The fused protein CFP10-ESAT6 with His-tag was expressed after inducing with IPTG and purified with affinity chromatography. This protein was used to immune the rabbit to obtained the polyclonal antibodies, and been analyzed with Western-blot and ELISA. RESULTS: The recombinant plasmid pET-cfp10-esat6 was success fully constructed, the recombinant fusion protein CFP10-ESAT6 could be expressed at relatively high levels, and the polyclonal antibodies of fusion protein were obtained. CONCLUSION: The successful construction and expression of the recombinant fusion protein CFP10-ESAT6 and the obtained polyclonal antibodies will be very helpful for the development of new anti-tuberculosis vaccine and the clinical serologic diagnosis.

[Protein-protein interaction between ESAT-6 and CFP-10 of mycobacterium tuberculosis].

OBJECTIVE: To investigate the protein-protein interaction between ESAT-6 and CFP-10 of mycobacterium tuberculosis. METHODS: ESAT-6 gene and CFP-10 gene were amplified from mycobacterium tuberculosis genome DNA. The ESAT-6 gene was subcloned into pGBKT7 and the CFP-10 gene was subcloned into pGADT7-Rec. After being verified with restriction endonuclease digestion and DNA sequencing, the recombinant vectors were transformed into yeast cell AH109 by lithium acetate method. RESULTS: The yeast cells co-transformed with pGBKT7-ESAT-6 and pGADT7-CFP-10 grew on SD/-Ade/-His/-Leu/-Trp plates, and beta-galactosidase activity assays showed positive results. CONCLUSION: ESAT-6 and CFP-10 protein could interact with each other in yeast cells.

[Study on the gene mutation of quinolone-resistant Mycobacterium tuberculosis isolated from Sichuan Province].

OBJECTIVE: To investigate the molecular mechanism of quinolone-resistance of M. tuberculosis and characterize the gene mutation in Sichuan Province. METHODS: Susceptibility of the clinical isolates to quinolones (ofloxacin, ciprofloxacin and sparfloxacin) was tested by the absolute concentration method. GyrA gene quinolone reasistance-determining region (QRDR) mutations M. tuberculosis were detected with PCR-SSCP and DNA sequencing. RESULTS: Of 68 clinical isolates of M. tuberculosis, 25 high-resistant, 11 low-resistant and 10 sensitive isolates were noted to have abnormal gyrA SSCP profile and different gyrA sequences from the standard strain H37Rv, and 14 sensitive and 8 low-resistant isolates were found with no mutation of gyrA gene. DNA sequencing unveiled Ser-->Thr mutation at codon 95, Asp-->Gly at codon 94, Ala-->Val at codon 90, and Ala-->Val at codon 83. CONCLUSION: This study confirmed the strong correlation between the quinolone-resistance and the mutation of gyrA gene, which might be a major molecular mechanism of quinolone-resistance in M. tuberculosis. The types of mutations exhibit no difference between Sichuan Province and other areas in China.