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Sivaranjani Murugesan Prakash Manivannan Gowrishankar Shanmugaraj Rathna Janarthanam Pandian Shunmugiah Karutha Ravi Arumugam Veera 《Applied microbiology and biotechnology》2017,101(8):3349-3359
Applied Microbiology and Biotechnology - Alpha-mangostin (α-MG) has been reported to be an effective antibacterial agent against planktonic cells of many Gram-positive bacteria. However, the... 相似文献
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Environmental signals that trigger bacterial pathogenesis and biofilm formation are mediated by changes in the level of cyclic dimeric guanosine monophosphate (c-di-GMP), a unique eubacterial second messenger. Tight regulation of cellular c-di-GMP concentration is governed by diguanylate cyclases and phosphodiesterases, which are responsible for its production and degradation, respectively. Here, we present the crystal structure of the diguanylate cyclase WspR, a conserved GGDEF domain-containing response regulator in Gram-negative bacteria, bound to c-di-GMP at an inhibitory site. Biochemical analyses revealed that feedback regulation involves the formation of at least three distinct oligomeric states. By switching from an active to a product-inhibited dimer via a tetrameric assembly, WspR utilizes a novel mechanism for modulation of its activity through oligomerization. Moreover, our data suggest that these enzymes can be activated by phosphodiesterases. Thus, in addition to the canonical pathways via phosphorylation of the regulatory domains, both product and enzyme concentration contribute to the coordination of c-di-GMP signaling. A structural comparison reveals resemblance of the oligomeric states to assemblies of GAF domains, widely used regulatory domains in signaling molecules conserved from archaea to mammals, suggesting a similar mechanism of regulation. 相似文献
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Marta González-Alvarez Arias MS Fernández MJ Gude L Lorente A Alzuet G Borrás J 《Bioorganic & medicinal chemistry letters》2008,18(11):3286-3290
We have focused our interest on the tetrapyridoacridine ligand tetrapyrido[3,2-a:2',3'-c:3',2'-h: 2',3'-j]acridine (tpac), as a model system for the preparation of novel copper-based artificial nucleases. The complex of copper(II)-tpac cleaves supercoiled pUC18 plasmid DNA in an oxidative manner by photoactivation with visible light, exhibiting maximum cleaving efficiency at 1:2 metal-ligand stoichiometric ratio. We propose an interaction of the copper-tpac complex with DNA through both major and minor grooves and a photocleavage mechanism via the formation of hydroxyl radicals and singlet oxygen or singlet oxygen-like species. 相似文献
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Blizzard TA Gude C Morgan JD Chan W Birzin ET Mojena M Tudela C Chen F Knecht K Su Q Kraker B Mosley RT Holmes MA Sharma N Fitzgerald PM Rohrer SP Hammond ML 《Bioorganic & medicinal chemistry letters》2006,16(4):834-838
A series of 19-substituted androstenediol derivatives was prepared. Some of the novel analogs were surprisingly potent and selective ligands for ER-beta. 相似文献
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Rajan Sharma Ram P. Thakur Senapathy Senthilvel Spurthi Nayak S. Veera Reddy Veeranki Panduranga Rao Rajeev K. Varshney 《Mycopathologia》2011,171(3):223-230
Fusarium species are dominant within the sorghum grain mold complex. Some species of Fusarium involved in grain mold complex produce mycotoxins, such as fumonisins. An attempt was made to identify Fusarium spp. associated with grain mold complex in major sorghum-growing areas in India through AFLP-based grouping of the isolates
and to further confirm the species by sequencing part of α-Elongation factor gene and comparing the sequences with that available in the NCBI database. The dendrogram generated from the AFLP data clustered
the isolates into 5 groups. Five species of Fusarium—F. proliferatum, F. thapsinum, F. equiseti, F. andiyazi and F. sacchari were identified based on sequence similarity of α-Elongation factor gene of the test isolates with those in the NCBI database. Fusarium thapsinum was identified as predominant species in Fusarium—grain mold complex in India and F. proliferatum as highly toxigenic for fumonisins production. Analysis of molecular variance (AMOVA) revealed 54% of the variation in the
AFLP patterns of 63 isolates was due to the differences between Fusarium species, and 46% was due to differences between the strains within a species. 相似文献
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Pentoxifylline (PTX), a methylxanthine derivative is a non-steroidal immunomodulating agent with unique hemorheologic properties. It is used in the treatment of intermittent claudication as it increases the amount of oxygen reaching tissues by increasing the flexibility of red blood cells. Recently, it has also shown to exhibit anti-metastatic and anti-angiogenic activities in B16F10 melanoma cells both in vitro as well as in vivo. As per the reports, the choice of drug in the treatment of breast cancer is paclitaxel, but the major limitation is its toxicity. However, the effects of PTX on metastatic processes in breast cancer are not currently known. Therefore, in this study, we have examined the effect of PTX in MDA-MB-231 human breast cancer cells. The MTT assay showed dose- and time-dependent decreases in cellular proliferation. The non-toxic concentration of PTX selected were 1, 2.5 and 5 mM for 24 h. PTX induced a G0-G1 cell-cycle arrest leading to apoptosis. Further, it affected adhesion to both the matrigel and collagen type-IV in a time- and dose-dependent manner. The PTX impeded the migration of MDA-MB-231 cells and also decreased the activities of both MMP-2 and MMP-9. Thus, PTX at non-toxic doses affected cellular proliferation, adhesion, migration and invasion. These results demonstrate its anti-metastatic effect on MDA-MB-231 cells, and further studies need to be carried out to understand the mechanism of action. 相似文献
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