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Salinity Impact on Bacterial Community Composition in Five High-Altitude Lakes from the Tibetan Plateau,Western China 总被引:1,自引:0,他引:1
Yongqin Liu Tandong Yao Nianzhi Jiao Liping Zhu Anyi Hu Xiaobo Liu 《Geomicrobiology journal》2013,30(5):462-469
The influence of salinity and geographical distance on bacterial community composition (BCC) in five freshwater, oligosaline or polysaline lakes located at altitudes higher than 4400 m on the central and southern Tibetan Plateau were investigated using the 16S rRNA gene clone library approach together with multivariate analysis of environmental variables. A total of 10 clone libraries were constructed with two libraries in each lake, one in the epilimnion and the other in the hypolimnion. Geographical distance was not found to impact BCC significantly, but salinity, chl a and lake hydraulic retention time were significant factors influencing the BCC. Bacteria in lakes located on the central and southern Plateau owned the same community composition as that observed from the eastern Tibetan lakes. They were both predominated by Bacteroidetes and Cyanobacteria, had low taxon richness, and similar typical freshwater clusters and distributed characteristics. Supplemental materials are available for this article. Go to the publisher's online edition of Geomicrobiology Journal to view the supplemental file. 相似文献
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Li-bo Cheng Lei Cheng Hui-e Bi Zhi-qing Zhang Jin Yao Xiao-zhong Zhou Qin Jiang 《Biochemical and biophysical research communications》2014
Patients with age related macular degeneration (AMD) will develop vision loss in the center of the visual field. Reactive oxygen species (ROS)-mediated retinal pigment epithelium (RPE) cell apoptosis is an important contributor of AMD. In this study, we explored the pro-survival effect of α-melanocyte stimulating hormone (α-MSH) on oxidative stressed RPE cells. We found that α-MSH receptor melanocortin 1 receptor (MC1R) was functionally expressed in primary and transformed RPE cells. RPE cells were response to α-MSH stimulation. α-MSH activated Akt/mammalian target of rapamycin (mTOR) and Erk1/2 signalings in RPE cells, which were inhibited by MC1R siRNA knockdown. α-MSH protected RPE cells from hydrogen peroxide (H2O2)-induced apoptosis, an effect that was almost abolished when MC1R was depleted by siRNA. α-MSH-mediated S6K1 activation and pro-survival effect against H2O2 was inhibited by Akt inhibitors (perifosine, MK-2206 and LY294002). Further, mTOR inhibition by rapamycin, or by mTOR siRNA knockdown, diminished α-MSH’s pro-survival effect in RPE cells. Thus, Akt and its downstream mTOR signaling mediates α-MSH-induced survival in RPE cells. In summary, we have identified a new α-MSH–MC1R physiologic pathway that reduces H2O2-induced RPE cell damage, and might minimize the risk of developing AMD. 相似文献
46.
Leishmania major LmACR2 is a pentavalent antimony reductase that confers sensitivity to the drug pentostam 总被引:4,自引:0,他引:4
Zhou Y Messier N Ouellette M Rosen BP Mukhopadhyay R 《The Journal of biological chemistry》2004,279(36):37445-37451
Arsenicals and antimonials are first line drugs for the treatment of trypanosomal and leishmanial diseases. To create the active form of the drug, Sb(V) must be reduced to Sb(III). Because arsenic and antimony are related metalloids, and arsenical resistant Leishmania strains are frequently cross-resistant to antimonials, we considered the possibility that Sb(V) is reduced by a leishmanial As(V) reductase. The sequence for the arsenate reductase of Saccharomyces cerevisiae, ScAcr2p, was used to clone the gene for a homologue, LmACR2, from Leishmania major. LmACR2 was able to complement the arsenate-sensitive phenotype of an arsC deletion strain of Escherichia coli or an ScACR2 deletion strain of Saccharomyces cerevisiae. Transfection of Leishmania infantum with LmACR2 augmented Pentostam sensitivity in intracellular amastigotes. LmACR2 was purified and shown to reduce both As(V) and Sb(V). This is the first report of an enzyme that confers Pentostam sensitivity in intracellular amastigotes of Leishmania. We propose that LmACR2 is responsible for reduction of the pentavalent antimony in Pentostam to the active trivalent form of the drug in Leishmania. 相似文献
47.
Recently, a class of about 22 nucleotides (nt) small RNA has been discovered in many eukaryotes, termed microRNAs (miRNAs),
which have a variety of functions. Many recent findings have demonstrated that viruses can also encode their own miRNAs. Meanwhile,
other findings reveal a relationship between host miRNA and viral infection. These findings suggest a tight relationship between
host and viral infection via miRNA pathway. This article introduces the miRNAs encoded by viruses and reviews the advances
of the interaction of the mammalian host miRNAs and viral infection. 相似文献
48.
Human chorionic gonadotropin (hCG) has been used as an anti-fertility vaccine and as a target for cancer immunotherapy. We have explored the use of three copies of C3d in DNA vaccine as molecular adjuvant to improve the immunogenicity of this hormone in previous work and found that the immune response induced by pcDNA3-hCGbeta-C3d3 has been enhanced 243-fold compared with pcDNA3-hCGbeta following DNA immunization in BALB/c mice. In the present study, a new functionally active DNA vaccine of hCGbeta-C3d3 chimera based on pCMV4 vector has been described. We compared the expression efficiency of pCMV4 and pcDNA3 eukaryotic vectors for hCGbeta and hCGbeta-C3d3 fusion protein and the immune response of mice immunized with pcDNA3-hCGbeta, pCMV4-hCGbeta, pcDNA3-hCGbeta-C3d3 and pCMV4-hCGbeta-C3d3, respectively, at 25, 50 and 100 pmol dose, and further analyzed the levels of Th1 and Th2 cytokines produced by spleen lymphocytes of the immunized mice upon hCG restimulation in vitro. It was found that pCMV4 vector achieved 1.3-1.5-fold higher protein expression and raised 1.1-1.2 (primary) and 1.2-1.3 (booster) logs higher titer of anti-hCGbeta IgG than pcDNA3. Mice vaccinated with 50 pmol of hCGbeta-C3d3-DNAs elicited the highest titer of hCGbeta-specific antibody among the serial doses and the immune response induced by pCMV4-hCGbeta-C3d3 were, respectively, 1.3, 1.3 and 1.2 logs higher than that of pcDNA3-hCGbeta-C3d3 and 2.2, 2.9 and 2.4 logs higher than that of pCMV4-hCGbeta at week 2 following the booster immunization. Moreover, we observed that the production of IL-4 and IL-10 increased in mice vaccinated with hCGbeta-C3d3-DNAs and the ratio of IL-4/IFN-(gamma) showed a Th2 bias of immune response in the mice immunized with hCGbeta-C3d3-DNAs. These findings indicated that gene fusion of C3d3 to hCGbeta, as a means of harnessing the adjuvant potential of the innate immune system, may improve the antigen-specific Th2 humoral immune response of the hCGbeta DNA vaccine and the pCMV4 vector is a more ideal eukaryotic vector for DNA vaccine than pcDNA3. 相似文献
49.
Wen W Zhu F Zhang J Keum YS Zykova T Yao K Peng C Zheng D Cho YY Ma WY Bode AM Dong Z 《The Journal of biological chemistry》2010,285(50):39108-39116
MST1 (mammalian STE20-like kinase 1) is a serine/threonine kinase that is cleaved and activated by caspases during apoptosis. Overexpression of MST1 induces apoptotic morphological changes such as chromatin condensation, but the mechanism is not clear. Here we show that MST1 induces apoptotic chromatin condensation through its phosphorylation of histone H2AX at Ser-139. During etoposide-induced apoptosis in Jurkat cells, the cleavage of MST1 directly corresponded with strong H2AX phosphorylation. In vitro kinase assay results showed that MST1 strongly phosphorylates histone H2AX. Western blot and kinase assay results with a mutant S139A H2AX confirmed that MST1 phosphorylates H2AX at Ser-139. Direct binding of MST1 and H2AX can be detected when co-expressed in HEK293 cells and was also confirmed by an endogenous immunoprecipitation study. When overexpressed in HeLa cells, both the MST1 full-length protein and the MST1 kinase domain (MST1-NT), but not the kinase-negative mutant (MST1-NT-KN), could induce obvious endogenous histone H2AX phosphorylation. The caspase-3 inhibitor benzyloxycarbonyl-DEVD-fluoromethyl ketone (Z-DEVD-fmk) attenuates phosphorylation of H2AX by MST1 but cannot inhibit MST1-NT-induced histone H2AX phosphorylation, indicating that cleaved MST1 is responsible for H2AX phosphorylation during apoptosis. Histone H2AX phosphorylation and DNA fragmentation were suppressed in MST1 knockdown Jurkat cells after etoposide treatment. Taken together, our data indicated that H2AX is a substrate of MST1, which functions to induce apoptotic chromatin condensation and DNA fragmentation. 相似文献
50.
通过PCR扩增家蚕二分浓核病毒(Bombyx mori bidensovirus,BmBDV)VD1-ORF4基因序列中的两个DNA片段,将测序正确的两个目的片段分别亚克隆到原核表达载体pET-30a上,通过不同浓度的IPTG对含有重组质粒的大肠杆菌BL21(DE3)进行诱导,对诱导产物进行SDS-PAGE和Westen blot分析.结果表明,这两个截短多肽都获得了表达,其N-端融合有6个组氨酸.将割胶纯化的蛋白多肽与佐剂充分研磨,以研磨后的匀浆液对昆明小鼠进行皮下多点注射.获得的抗血清分别对原核诱导表达产物进行Western blot分析,结果表明,在特定的位置都能杂交到一条特异的蛋白带,表明制备的两个多抗能为深入研究VD1-ORF4基因的功能提供基础. 相似文献