With the plasmid DNA from a clinical isolate of enterotoxigenic Escherichia coli (ETEC) H 10407 as template, PCR-mediated cloning of the sequence encoding the heat-labile toxin B subunit (L T -B) has been carried out. Then this sequence was recloned into the pTrc 99A and pET23a expression vectors to give the pJasmids pTRCLTB and pETLTB, respectively. After induction, the former plasmid provides...

background: chitin is an abundant natural polysaccharide found in fungi, algae, and exoskeleton of insects. several bacterial species are capable of utilizing chitin as their carbon source. these bacteria produce chitinases for degradation of chitin into n-acetyl-d-glucosamine. so far, regulation of the chitinase encoding genes has been studied in different bacterial species. among bacillus spe...

Background: Chitin is an abundant natural polysaccharide found in fungi, algae, and exoskeleton of insects. Several bacterial species are capable of utilizing chitin as their carbon source. These bacteria produce chitinases for degradation of chitin into N-acetyl-D-glucosamine. So far, regulation of the chitinase encoding genes has been studied in different bacterial species. Among Bacillus spe...

a practical and green method for the synthesis of 5h-dibenzo[b,i]xanthene-tetraones and spiro[dibenzo[b,i]xanthene-13,3'-indoline]-pentaones by the condensation of 2-hydroxynaphthalene-1,4-dione with aldehydes or isatins, respectively, in the presence of a catalytic amount of cellulose sulfuric acid (csa) under solvent-free conditions at 100 °c is described. the significant features of this pro...