Toxin production Properties Dispensable, but essential under certain situations where survival and spread are at stake Genes frequently carried on plasmids and temperate bacteriophage BIOL 533 7 Lecture 9
BIOL 533 7 Lecture 9 Toxin Production • Properties – Dispensable, but essential under certain situations where survival and spread are at stake – Genes frequently carried on plasmids and temperate bacteriophage
Toxin production Found on phage; toxin genes for Diphtheria o Botulism o Scarlet fever Toxic streptococci (flesh-eating") Found on plasmids E coli toxin causes diarrhea S aureus toxin causes"scalded skin syndrome E,CO0157:H7 BIOL 533 Lecture 9
BIOL 533 8 Lecture 9 Toxin Production – Found on phage; toxin genes for: • Diphtheria • Botulism • Scarlet fever • Toxic streptococci (“flesh-eating”) – Found on plasmids: • E. coli toxin causes diarrhea • S. aureus toxin causes “scalded skin syndrome” • E. coli 0157:H7
Toxin production Properties Mobile elements ensure that genes can be spread to nontoxigenic derivatives or be lost from cell Experimentally called"curing"get nontoxigenic derivatives Phase of production Some produced continuously by growing bacteria Other synthesized when cells enter stationary phase(true also for many antibiotics) BIOL 533 Lecture 9
BIOL 533 9 Lecture 9 Toxin Production – Properties • Mobile elements ensure that genes can be spread to nontoxigenic derivatives or be lost from cell – Experimentally called “curing”—get nontoxigenic derivatives – Phase of production • Some produced continuously by growing bacteria • Other synthesized when cells enter stationary phase (true also for many antibiotics)
Toxin production Explanation Certain toxins may help bacteria get scarce nutrients Example: high levels of diphtheria toxin produced when cell depleted of iron Very little free iron in normal tissue Is this a way for organisms to obtain it from dead tissue? BIOL 533 Lecture 9
BIOL 533 10 Lecture 9 Toxin Production – Explanation • Certain toxins may help bacteria get scarce nutrients • Example: high levels of diphtheria toxin produced when cell depleted of iron – Very little free iron in normal tissue – Is this a way for organisms to obtain it from dead tissue?
Toxin production Sporulating bacteria sometimes release toxins during spore formation Bacterial cells eventually lyse and liberate cytoplasmic proteins, including toxins Examples: organisms that cause botulism, gas gangrene, or tetanus In contaminated wound some organisms are growing and some are sporulating End result is continual production BIOL 533 Lecture 9
BIOL 533 11 Lecture 9 Toxin Production – Sporulating bacteria sometimes release toxins during spore formation • Bacterial cells eventually lyse and liberate cytoplasmic proteins, including toxins – Examples: organisms that cause botulism, gas gangrene, or tetanus • In contaminated wound, some organisms are growing and some are sporulating – End result is continual production