Synthesis, antimicrobial activity and QSAR studies of 2,5-disubstituted benzoxazoles.

In this study, a new series of 2,5-disubstituted benzoxazoles was synthesized and their structures were elucidated by elemental analysis, MASS, (1)H-NMR, (13)C-NMR and IR spectral data. Newly and previously synthesized 2,5-disubstituted benzoxazole derivatives were evaluated for antibacterial and antifungal activity against standard strains and their drug-resistant isolates. Microbiological results showed that the compounds presented a large spectrum of activity having MIC values of 250-7.8 microg mL(-1) against the tested microorganisms. Among the newly synthesized derivatives 3-22, compound 11 was the most active against Candida krusei out of all; however, it was one dilution less potent than standard drug fluconazole. In addition, all the new and previous compounds were more active than standard drugs ampicillin trihydrate and rifampicin against Pseudomonas aeruginosa and its gentamicin-resistant isolate. The 2D-QSAR (Quantitative Structure-Activity Relationship) analysis of a set of newly and previously synthesized benzoxazoles tested for growth inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA) was also performed by using multivariable regression analysis. The activity contributions for substituent effects of these compounds were determined from the correlation equation for predictions of the lead optimization.

Detection of virulence factors of Escherichia coli from children by multiplex polymerase chain reaction.

A total of 161 Escherichia coli (E. coli) strains isolated from children with urinary tract infection (UTI) were analysed for the genes encoding the virulence factors such as pyelonephritis (pap), s fimbriae (sfa), afimbrial adhesin I (afaI), haemolysin (hly), cytotoxic necrotising factor I (cnf I) and aerobactin (aer) by multiplex PCR. Ninety-four E. coli strains were found to carry at least one virulence factor. Therefore, 58.38% of total population was positive for one virulence gene at least. Percentage of genes within the total population for pap, sfa, afaI, hly, cnf I and aer was found as 22.98, 6.21, 9.94, 1.24, 9.94 and 39.75, respectively. Our analysis showed that sfa-pap (p < 0.001); pap-aer, afaI-aer and cnf I-pap (P < 0.05) and hly-sfa (p < 0.01) significantly co-occurred in their respective samples. In the light of these findings, we suggest an important role of pap causing UTI.

Age-related enzyme activity in different genotypes of alcohol dehydrogenase (Adh) in Drosophila melanogaster.

Ageing is a complex phenomenon with possibly a multitude of contributions from many genes. In our study, we tested the degree of contribution of alcohol dehydrogenase (Adh ) polymorphism (as specific enzyme activities) to ageing in Drosophila melanogaster. Our results indicate an overdominance of FS genotypes on ageing flies, with the two homozygotes, i.e., FF and SS, having significantly lower mean longevities. However, that kind of life-span-genotype relationship was not detected when the genotypes were observed for the immediate function of the Adh locus, ADH enzyme activity in which mean ADH-FF activity was the highest as compared to those of ADH-FS and ADH-SS. This irrelevancy of the ADH enzyme function to ageing, with an obvious overdominance effect of Adh locus, is discussed considering Adh 's known relation to other life history traits.