A dinuclear silver compound with 5,6,7-trimethyl-[1,2,4]triazolo[1,5-a]pyrimidine with a short Ag-Ag bond. Synthesis, characterization, single-crystal structure analysis and cytostatic activity

A new dinuclear coordination compound with the ligand 5,6,7-trimethyl[1,2,4]triazolo[1,5-a]pyrimidine (abbreviated as tmtp) is described, together with its 3D crystal structures and spectroscopic properties. The compound shows a high cytostatic activity in ovarian cancer cell lines.The solid state structure of the compound is dinuclear based, in which the ligand tmtp uses two nitrogens (N3 and N4) to chelate to two different Ag(I) ions. The Ag-Ag distance is relatively short (3.109 Å), but is considered as too long for M-M bonding. The Ag(I) coordination is completed by weakly coordinated, asymmetric bidentate nitrate anions (Ag-O = 2.481-2.819 Å).     

Production and Characterization of Protein Encapsulated Silver Nanoparticles by Marine Isolate Streptomyces parvulus SSNP11

Production of protein encapsulated silver nanoparticles (AgNPs) assisted by marine actinomycetes strain has been investigated. The selective isolate was identified as Streptomyces parvulus SSNP11 based on chemotaxonomic and 16S rRNA analysis. Maximum AgNPs production was observed within 24 h incubation time. The produced AgNPs are spherical in shape with monodispersive and crystalline in nature. The particle size distribution ranges from 1.66 to 11.68 nm with a mean size of 2.1 nm. The biosynthesized AgNPs revealed stretching vibrations of primary and secondary amines along with C–H and C–N, suggesting that metabolically produced proteins are involved in size regulation of reduced AgNPs. These particles possess an average negative zeta potential value of 81.5 mV with an electrophoretic mobility of 0.000628 cm²/Vs. The biosynthesized nanoparticles revealed antimicrobial property against gram negative as well as gram positive bacterial strains.     

Effect of lipopolysaccharide core synthesis mutations on the production of Vibrio cholerae O-antigen in Escherixhia coli K-12

The rfb genes of Vibrio cholerae O1 (Ogawa serotype) were subcloned into a derivative of pBR322. This plasmid was transformed into several Escherichia coli K-12 mutant strains which produce an incomplete lipopolysaccharide (LPS)-core-oligosaccharide region. The data indicate that the V. cholerae O-antigen is assembled onto the E. coli LPS and that at least two glucoses are needed in the core in order to achieve a high level of production. These data are consistent with the reported presence of glucose in the V. cholerae LPS-core-oligosaccharide region.