RESUMEN
The possibility of homologous and heterologous transception of Cry+ plasmids in Bacillus thuringiensis is demonstrated. Cry+ plasmids from crystal bearing strain of Bacillus thuringiensis were transferred into acrystalline strain belonging to H5 serotype by mutual incubation. The donor strain was previously marked by the transmissive plasmid pAM beta 1 coding for erythromycin and lincomycin resistance. The transcipients having acquired the ability to synthesize delta-endotoxin were referred to H5 serotype due to their phenotype. By analogous method Cry+ plasmid was transferred from Bacillus thuringiensis to Bacillus cereus. Bacillus cereus strain GP7 was used as a recipient strain resistant to tetracycline. The presence of delta-endotoxin in transcipients was confirmed by bioprobes and immunoenzyme assay. To prove the transfer of Cry+ plasmid the plasmid profiles of the parent strains and transcipients have been analyzed. The formation of cellular contacts during mutual incubation of Bacillus thuringiensis and Bacillus cereus strains was demonstrated by electron microscopic study of ultrafine cuts.
Asunto(s)
Bacillus thuringiensis/genética , Proteínas Bacterianas , Toxinas Bacterianas , Endotoxinas/genética , Plásmidos , Bacillus thuringiensis/ultraestructura , Toxinas de Bacillus thuringiensis , Cristalización , Endotoxinas/biosíntesis , Vectores Genéticos , Proteínas Hemolisinas , Control Biológico de VectoresRESUMEN
Electron microscopy and the hemagglutination test were used to study the effect of low-frequency and low-amplitude ultrasound (26.5 kHz, 30 m) on the adhesiveness of E. coli cells, strain 815, possessing Type I pili. Mild sonication providing the assanation effect during intraoperational treatment of the infected peritonium was found to remove the majority of flagella and pili, despite the fact that the cells seemed to be unimpaired. After sonication the ability of bacteria to cause mannose-sensitive hemagglutination of guinea-pig red blood cells decreased more than 8-fold. The data obtained suggest that the diminution of adhesiveness might be a possible mechanism of the sonication-induced assanation effect.