Flashcards in Driks 3 Deck (16)
What are 3 ways toxins act?
1. form pore
-destroy cellular homeostasis
2. go through membrane and do something intracellularly
3. toxin engages receptor on host cell surface and triggers intracellular events
What is a type 3 secretory apparatus?
Gram negative bacteria
-tip of needle is able to interact with host cells and partially penetrate the host cell
-serves as conduit for proteins in the bacteria to flow into the host cell--->cause pathogenic events and often allow the bacteria to be taken up
-ex it induces cytoskeletal rearrangement-like in the pedestal
What does novobiocin quinolines do?
inhibit gyrase needed for successful completion of DNA replication
-gyrase-detangles knots in DNA synthesis
Are transcription and translation coupled in bacteria?
What are the steps in peptidoglycan synthesis?
1. subunits of peptidoglycan are synthesized in the cytoplasm
2. subunits are transferred across the membrane by a carrier molecule
3. newly transferred subunits are cross linked to the peptidoglycan already present on the other side on the membrane
What are the major targets of antibiotics?
1. RNA polymerase
2. RIbosome inhibitors
3. cell membrane
4. peptidoglycan synthesis
What is an example of a siderophores system? How does it work?
Bacteria does the environment with siderophores that bind iron at high affinity and then takes up the siderophore into the cell-takes the iron and spits it back out
-siderophores are essential for virulence-can be encoded on plasmids and shared among bacteria leading to the spread of virulence
What happens if a drug impairs the inner membrane of a bacteria?
-the relevant enzymes are compartmentalized in the inner membrane
What do enzymes that detoxify active oxygen created during respiration show?
-useful for diagnosis
-can be virulence factors, since they can detoxify host-generated active oxygen
-give clues for antimicrobial angents
What are two generic stress responses?
-synthesis of proteins to protect against heat
What are pathogenic stress responses?
Are order and timing of gene expression important in bacteria?
-gene regulation is hierarchical
-gene promoter is activated by a certain environmental stimulus-->activates another tier
What is the most fundamental method of analyzing bacteria?
pure culture technique
What is the rate of bacterial growth depend on?
1. nature of the culture medium and presence of any appropriate supplemental nutrients
2. the presence or absence of oxygen
3. the temperature
What are 3 classes of molecule that must be made prior to cell division?
1. DNA replication
2. Protein synthesis