endotoxins and some gram positive stuff p127

Question 1

What do endotoxins do? classic endotoxin?

Answer 1

lipid A is the classic endotoxin from gram negative bacteria.
it activates macrophages, complement, and tissue factor.
macrophages release IL-1 (fever), TNF (fever and hypotension) and NO (hypotension). complement C3a causes hypotension and edema; C5a does neutrophil chemotaxis.
tissue factor can activate the coag cascade and cause DIC.
(edema, NO, DIC, outer membrane, TNF-alpha, O-antigen, eXtremely heat stable, IL-1, neutrophil chemotaxis)

Question 2

F+ X F- conjugation vs. Hfr X F- conjugation

Answer 2

both involve exchange of bacterial DNA. F+ X F- is just exchange of plasmid DNA through sex pili; HfrX F- means the plasmid has been incorporated into the chromosme and may transfer both plasmid and flanking chromosomal genes

Question 3

transduction

Answer 3

transfer of bacterial DNA via a bacteriophage. in generalized transduction, a lytic phage accidentally picks up bacterial chromosomal info in the viral capsid. In specialized transduction, a lysogenic phage infects the bacterium, viral DNA incorporates into bacterial chromosme. when DNA is excised flanking bacterial DNA may come along for the ride.

Question 4

What bacterial toxins are encoded in a lysogenic phage?

Answer 4

ABCDE: ShigA-like toxin (EHEC), some botulism strains, cholera toxin, diptheria toxin, and erythrogenic toxin of strep pyrogenes

Question 5

lactose fermenting bacteria

Answer 5

grow pink colonies on MacConkey agar. Klebsiella, E coli, serratia (citrobacter, enterobacter)

Question 6

EMB agar

Answer 6

lactose fementers grow as purple/black colonies. E coli grows with a green sheen