RESUMO
Novel macrolides epothilones, produced by cellulolytic myxobacterium Sorangium cellulosum, have the activity to promote microtubule assembly, and are considered to be a potential successor to the famous antitumor drug taxol. The biosynthetic genes leading to the epothilones are clustered into a large operon. The multi-enzyme complex is a hetero-gene cluster of polyketide synthase (PKS) and non-ribosomal peptide synthetases (NRPS) and contains several functional modules, i.e. a loading module, one NRPS module, eight PKS modules, and a P450 epoxidase. The former ten modules biosynthesize desoxyepothilone (epothilones C and D), which is then epoxidized at C12 and C13 and converted into epothilones (epothilones A and B) by the P450 epoxidase. The NRPS module is responsible for the formation of the thiazole side chain from cysteine. The biosynthesis procedure of epothilones can be divided into 5 stages, i.e. formation of holo-ACP/PCP, chain initiation and thiazole ring formation, chain elongation, termination and epoxidation, and post-modification. The analysis of the gene cluster and the biosynthetic pathway reveals that novel epothilone analogs could not only be produced by chemical synthesis/modification, tranditional microbial technologies, but also can be genetically manipulated through combinatiorial biosynthesis approaches.
Assuntos
Proteínas de Bactérias , Genética , Metabolismo , Epotilonas , Química , Metabolismo , Estrutura Molecular , Família Multigênica , Genética , Fisiologia , Myxococcales , Genética , Metabolismo , Peptídeo Sintases , Genética , Metabolismo , Policetídeo Sintases , Genética , MetabolismoRESUMO
Aquaneem, an emulsified product prepared from the neem (A. indica) kernel was tested against four pathogenic bacteria of fish (i.e. Aeromonas hydrophila, Pseudomonas fluorescens, Escherichia coli and Myxobacteria spp.) to test its efficacy as an antibacterial agent. Growth inhibitory property of the product at 10, 15 and 20 ppm has been noticed and recorded. The percentage reduction of bacterial cell population was noted to be maximum on 9th day at 20 ppm concentration (i.e. 70.14%, 74.15% and 61.75% for A. hydrophila, P. fluorescens and E. coli respectively) with the only exception of myxobacteria which showed maximum reduction percentage (63.90%) on 15th day. Among all the bacteria tested A. hydrophila, P. fluorescens and Myxobacteria spp. exhibited maximum sensitivity to Aquaneem in terms of percentage reduction of bacterial cell population in comparison to E. coli.
Assuntos
Aeromonas hydrophila/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Peixes/microbiologia , Myxococcales/efeitos dos fármacos , Extratos Vegetais/farmacologia , Plantas Medicinais , Pseudomonas fluorescens/efeitos dos fármacosRESUMO
Realizamos un estudio detallado de la especie bacteriana Mixococcus xanthus, perteneciente al Orden Mixobacteriales, con la finalidad de estudiar sus cambios morfológicos y características bacteriolíticas. Pudimos obtener cultivos puros, lo que nos facilitó el estudio de su ciclo vital. Observamos sus características culturales y morfológicas, seguimos por hora su poliformismo, hasta la observación de microcistos. Comprobamos que la bacteria de nuestro estudio era bacteriolítica, siendo capaz de lisar colonias bacterianas tanto de bacterias gram positivas como gram negativas, lo que nos indica su capacidad de formar sustancias antimicrobianas