The Trojan Horse of the microbiological arms race: phage-encoded toxins as a defence against eukaryotic predators.
Environ Microbiol
; 16(2): 454-66, 2014 Feb.
Article
en En
| MEDLINE
| ID: mdl-23981100
Phage-encoded Shiga toxin (Stx) acts as a bacterial defence against the eukaryotic predator Tetrahymena. To function as an effective bacterial anti-predator defence, Stx must kill a broad spectrum of predators. Consistent with that assertion, we show here that bacterially encoded Stx efficiently kills the bacteriovore Acanthamoeba castellanii in co-culture. We also show that, in addition to Stx, the phage-encoded exotoxin, diphtheria toxin (Dtx) expressed by Corynebacterium diphtheriae also can function as part of an anti-predator strategy; it kills Acanthamoeba in co-culture. Interestingly, only exotoxins produced by bacteria internalized by the Acanthamoeba predator are cytolethal; the presence of purified Dtx or Stx in culture medium has no effect on predator viability. This finding is consistent with our results indicating that intoxication of Acanthamoeba by these exotoxins does not require a receptor. Thus bacteria, in the disguise of a food source, function as a 'Trojan Horse', carrying genes encoding an exotoxin into target organisms. This 'Trojan Horse' mechanism of exotoxin delivery into predator cells allows intoxication of predators that lack a cell surface receptor for the particular toxin, allowing bacteria-bearing exotoxins to kill a broader spectrum of predators, increasing the fitness of the otherwise 'defenceless' prey bacteria.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Corynebacterium diphtheriae
/
Toxina Shiga
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Acanthamoeba castellanii
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Antibiosis
Aspecto:
Determinantes_sociais_saude
Idioma:
En
Revista:
Environ Microbiol
Asunto de la revista:
MICROBIOLOGIA
/
SAUDE AMBIENTAL
Año:
2014
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Reino Unido