Lambda prophage decreases Escherichia coli sensitivity to human serum bactericidal effect.
Rev Latinoam Microbiol
; 35(1): 71-5, 1993.
Article
em En
| MEDLINE
| ID: mdl-8140334
Escherichia coli C600 and C600(lambda) strains were tested for their susceptibility to the bactericidal action of 4% normal human serum. C600 survival was reduced to 30%, 23% and 16% after 60, 150 and 180 min of exposure to serum, respectively, whereas the percentage of survival of C600(lambda) was 199, 109 and 65% at the same times. The estimated exposition times for 50% killing showed an eight-fold difference, they were 23 and 202 min for C600 and C600(lambda), respectively. None of the two strains tested was killed when incubated with serum whose alternative complement pathway was inactivated by heating at 50 degrees C for 20 min, showing that this pathway, and not the classical one, was responsible of the bactericidal action, a conclusion further supported by the finding that both strains were differentially killed by the alternative complement pathway, C600 showing a 14X, 10X and 4X greater susceptibility than C600(lambda) at 60, 120 and 180 min of exposure to serum whose classical pathway was selectively inhibited by chelation with 10 mM EGTA plus 2 mM MgCl2. We feel that lambda phage may lower the serum sensitivity of its lysogen by altering the bacterial external surface, perhaps by the inclusion of some protein encoded by an accessory gene of the lambda genome, and thus interfering with either the formation, deposition or activity of the membrane attack complex.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Atividade Bactericida do Sangue
/
Bacteriófago lambda
/
Escherichia coli
Tipo de estudo:
Diagnostic_studies
Limite:
Humans
Idioma:
En
Revista:
Rev Latinoam Microbiol
Ano de publicação:
1993
Tipo de documento:
Article
País de afiliação:
México
País de publicação:
México