RESUMO
A selected antibody enzyme immunoassay (SAEIA) for the general detection of Vibrio cholerae O1 species has been developed using the immunological reagents of a rabbit antiserum specific for V. cholerae O1 classical Inaba 569B and immobilized cell fragments of V. cholerae O1 El Tor 85P6, and beta-D-galactosidase-labeled goat anti-rabbit immunoglobulin G as tracer. The SAEIA was specific for V. cholerae O1 species and showed low cross-reaction values to other microorganism species tested including Vibrio parahaemolyticus. The detection limit of the SAEIA was 4,500 cells per assay for all the 13 strains of V. cholerae O1 examined. Quantitative comparison on the growth of the El Tor 85P4 in several foods cultured for 24 hr were studied using the SAEIA. Preceding the experiments, little inhibition of every food homogenate for the measurement of the SAEIA was first demonstrated and then the homogenate was directly used for an assay sample. The interaction of the growth of Escherichia coli to that of V. cholerae O1 in a food was also found to be little under the mixed culturing of both bacteria using the SAEIA.
Assuntos
Microbiologia de Alimentos , Vibrio cholerae/isolamento & purificação , Escherichia coli/crescimento & desenvolvimento , Técnicas Imunoenzimáticas , Especificidade da Espécie , Vibrio cholerae/crescimento & desenvolvimentoRESUMO
In order to compare the antibacterial activity with Acyl-Lys-Lys(Thr)-Glu-OH (I), already reported, 3 kinds of Acyl-Lys-Lys(Glu)-Thr-OH (9a - c) and corresponding tetrapeptide (10), which were exchanged Thr for Glu on I, were synthesized by dicyclohexylcarbodiimide method. It was proved the (+)-6-methyloctanoyl-Lys-Lys(Glu)-Thr-OH (9a) shows antibacterial activity against 5 kinds of Gram-negative bacteria and against 2 kinds of Gram-positive bacteria, but that the others (9b), (9c), only have the weak one, and that tetrapeptide has against Gram-positive bacteria; and that those compounds have almost the same one as Acyl-Lys-Lys(Thr)-Glu-OH (I) has.
Assuntos
Antibacterianos/síntese química , Bactérias/efeitos dos fármacos , Oligopeptídeos/síntese química , Aminoácidos/análise , Antibacterianos/análise , Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos , Oligopeptídeos/farmacologia , Peptídeos/análise , Peptídeos/síntese química , Peptídeos/farmacologia , Relação Estrutura-AtividadeRESUMO
Three kinds of (formula; see text) were synthesized to investigate the relationship between the chemical structure and the antibacterial activities by acylation of the corresponding tetrapeptides. Acyl chlorides of (+)-6-Methyloctanoic acid (a component of colistin) and two kinds of other organic acid were employed as acylating agents. It was proved that one of three, (formula; see text) shows antibacterial activity against four kinds of Gram-negative bacteria and against Gram-positive bacteria, but that the other only have weak antibacterial activity.
