Ch 9: Bacterial Genomes and Evolution

get very weak, pseudomembrane formed

what are the symptoms of diphtheria?

gram positive Corynebacterium diphtheriae

what bacteria is diphtheria caused by?

gene encoding diphtheria toxin is carried by a beta phage virus and inserts its DNA into the Corynebacterium chromosome

how is diphtheria carried?

horizontal gene transfer

transfer of genes between cells of the same generation

transformation

process of importing free DNA into bacterial cells

forced

what type of transformation occurs with E.Coli and Salmonella?

donor is killed and free DNA is released

how is free DNA generated?

conjugative plasmid

carries genes for sex pili and for plasmid transfer

dissimilation plasmid

encodes enzymes for the catabolism of unusual compounds

r plasmid

encodes antibiotic resistance

carries antibiotic resistance gene

griffith experiment

scientist who found he could kill mice by injecting them with dead cells of a virulent strain but only if he also injected live cells of a non virulent mutant

transformation in gram positive bacteria

synthesis of competence factor, increase in cf is detected and activates sensor kinase/autophosphorylation, phosphorylation activates transformasome genes, which then releases DNA fragment

transformasome gene

membrane protein that picks up the free DNA from the environment

cell to cell contact, conjugative plasmid with conjugation pilus

conjugation involves blank and requires blank

gram negative

conjugation most commonly occurs in what type of cell?

F+

cell that contains a plasmid

F-

cell that does not have a plasmid

both cells become F+, no chromosomal DNA is transferred

recipients become recombinant

result of F+/F- mating

Hfr

high frequency recombination

cell in which a plasmid has integrated into the host chromosome

donor Hfr, recipient still F- but receives some genes from chromosomal DNA

result of Hfr x F- conjugation

F’ donor

plasmid that has host DNA

occurs when F factor cuts from the chromosome and takes some of the chromosomal DNA with it

recipient becomes F’

result of F’ x F- conjugation

generalized transduction

phage capsids packaging host DNA by mistake instead of phage DNA

specialized transduction

phage genome initially integrates into a specific DNA sequence in the host genome

restriction enzyme

bacteria’s immune system, molecular “scissor”

generalized recombination

requires that the two recombining molecules have long stretches of sequence homology

transposable elements

genes that can jump from one place in a genome to another or to a plasmid residing in the same cell

antibiotic resistance genes

transposons can carry