Bacterial Toxins General aspects Definition Soluble substances that alter normal metabolism of host cells with deleterious effects on the host ● Host range Known for bacteria, but possible that they play a role in diseases caused by fungi, protozoa, and worms BIOL 533 Lecture 9
BIOL 533 2 Lecture 9 Bacterial Toxins: General Aspects • Definition – Soluble substances that alter normal metabolism of host cells with deleterious effects on the host • Host range – Known for bacteria, but possible that they play a role in diseases caused by fungi, protozoa, and worms
Bacterial Toxins General aspects ToXin type Exotoxin--protein produced by bacteria either excreted or bound to bacterial surface and released when lysed Endotoxin-lps of the outer membrane of Gram bacteria Acts as toxin only under special circumstances BIOL 533 Lecture 9
BIOL 533 3 Lecture 9 Bacterial Toxins: General Aspects • Toxin type – Exotoxin—protein produced by bacteria either excreted or bound to bacterial surface and released when lysed – Endotoxin—lps of the outer membrane of Gram— bacteria • Acts as toxin only under special circumstances
Bacterial Toxins General aspects Specificity Some act on certain cell types Other affect wide range of cells and tissues Numbers produced by single bacterium Some produce none ● Pneumococci BIOL 533 Lecture 9
BIOL 533 4 Lecture 9 Bacterial Toxins: General Aspects • Specificity – Some act on certain cell types – Other affect wide range of cells and tissues • Numbers produced by single bacterium – Some produce none • Pneumococci
Is Toxin Important in Infection? Questions to ask: Is virulence quantitatively correlated with toxin production? Does the purified toxin produce damage Can a specific antibody(antitoxin) prevent or alleviate the manifestations of the disease? If toxin production is impaired by a mutation is the disease process affected? BIOL 533 Lecture 9
BIOL 533 5 Lecture 9 Is Toxin Important in Infection? • Questions to ask: – Is virulence quantitatively correlated with toxin production? – Does the purified toxin produce damage? – Can a specific antibody (antitoxin) prevent or alleviate the manifestations of the disease? – If toxin production is impaired by a mutation, is the disease process affected?
E If So, What are Toxin Properties?y Questions to ask: What is the mechanism of action? Why is it specific for certain cells or tissues? Does the pathogen make other toxins, and if sO, do they interact with one another? Some make none: pneumococci Some make only one: agents that cause cholera, diphtheria tetanus and botulism Other make many: staphylococci, streptococci BIOL 533 Lecture 9
BIOL 533 6 Lecture 9 If So, What are Toxin Properties? • Questions to ask: – What is the mechanism of action? – Why is it specific for certain cells or tissues? – Does the pathogen make other toxins, and if so, do they interact with one another? • Some make none: pneumococci • Some make only one: agents that cause cholera, diphtheria, tetanus, and botulism • Other make many: staphylococci, streptococci