lesson 2 Flashcards
stores all the information for the structures and functions of the cell
dna
. The genetic information of bacteria is stored in
chromosome and plasmid
the virulence factors of bacteria are mediated by
mutation
recombination processes (conjugation, transformation, transduction)
mobile genetics
plasmids
carry genes that recombine with the recipient
mobile genetics elements
Antibiotic resistance gene is acquired through
HGT
result of recombination
, an avirulent organism can acquire virulence genes.
are linear sequences of DNA that carry coded information for the structure and function of an organism
gene
-Bacterial chromosome is typically circular, double stranded chain of nucleotides.
chromosome
are extrachromosomal DNA molecules.
plasmids
examples of plasmids
F (fertility factors)
R (resistance)
Virulence plasmids
transposable element that contains the genes for transposition, and one or more more genes as well.
transposons
for toxin production or R genes conferring resistance to antibiotics
tetracycline, chloramphenicol, or ampicillin.
can move R genes from one plasmid to another or to bacterial genes.
transposon
are bacteria-associated from molecules that are required for a bacterium to cause disease.
virulence factors
Cluster of virulence genes
pathogenicity islands
Encode variety of virulence factors such as toxins, superantigens, adhesins, iron uptake systems, secretion systems III and IV, and many effectors that modulate behavior of host cells.
pathogenicity islands
are sequences of DNA that can move both within and between genomes
mobile genetic elements
examples of MGT
Plasmids, transposon54s, prophages, insertion sequences
Plasmids, transposon54s, prophages, insertion sequences
MGE
Change in nucleotide sequence of a gene
mutations
Forms of mutations observed in bacteria
base substitutions
microinsertions and microdeletions of base [pairs
reversions
deletions of multiple base pairs
insertions during recombination
translocation
inversions
code for the same amino acid
silent mutation
code for a different amino acid
missense mutation
code for a stop amino acid resulting to a truncated protein
nonsense mutation
-frameshift mutations: + or – frameshifts
Microinsertions and microdeletions of base pairs
mechanisms of antibiotic resistance
alteration of targets
alteration of membrane permeability
development of enzymes
alteration of enzymes
alteration of metabolic pathways
eliminations of antibiotic through membrane bound efflux pump
mechanism that usually affects the ribosomes of bacteria
alteration of targets
the antimicrobial agent can no longer bind to the target
alteration of target
caused by the resistance to erythromycin rifamycin and antimetabolites
alteration of targets
mechanism that induce changes in nature of proteins in the membrane
alteration of membrane permeability
alteration of membrane permeability causes resistance to
tetracycline, quinolonoes, some aminoglycosides
mechanism of bacteria that ables them to destroy or inactivate antimicrobial agents
development of enzymes
example of enzymes produced by bacteria to render penicillins and cephalosporins ineffective
beta-lactamase which catalyzes beta lactam rings
alteration of enzymes affect what antibiotic
sulfonamide
when bacteria bypasses pathways inhibited by the antimicrobial agent
alteration of metabolic pathways
what bacterias were found using efflux mechanism
e coli, salmonella typhimurium, pseudomonas auruginosa, campylobacter jejuni
what tpe of efflux pump is found in gram negative and positive bacteria
negative- single and multiple efflux component
positive- single component
a process that requires direct contact through the conjugative sex (plasmid) of the donor and recipient cells
conjugation
it trnasfers much larger quantities of dna
conjugation
the dna acquired is incorporated into bacteriophage nuclei acid and transferred by progeny of the phage to susceptible recipient cells
transduction
viruses that infect bacteria
bacteriophage
2 forms of transduction and differentiate
generalized is when the any gene (genetic marker) of the host bacterium can be transferred while specialized, only genes near the attachment site of the phage on the chromosome of host cell are involved
transfer of free or naked dna containing genes on a segment of chromosomal or plasmid dna from a lysed donor bacterium
transformation
the ability of the bacterium to take up free dna
competence
bacillus anthracis virulence factor
capsule, toxins/plasmid
clostridium botulinum virulence factors
neurotoxins/bacteriophages
e coli virulence factors
shiga-like toxin, enterotoxins, heat-stable toxin, siderophore production/transposons
salmonella Dublin virulence factors
serum resistance factor or plasmid
staphylococcus aureus virulence factor
enterotoxin (a,d,e) toxic shoxk syndrome factor 1
yersinia pestis virulence factors
coagulase, fibrinolysin
antibiotic resistance can be passed germ to germ by
mobile genetic elements like plasmid, transposon, bacteriophae
what ability does the sulfonamide resistant bacteria acquired
to use ready made folic acid from environment and no longer need PABA
