lectures 1-6 miscellaneous Flashcards
what is an example of parasitism?
malaria (plasmodium) and using mosquito as vector
what is an example of mutualism?
rhizobium and legumes, rhiz form nodules on plant roots and nodules help with providing nitrogen support
what is superinfection
if flora is removed by inappropriate use of antibiotics, occurs with resistant microbes
what are virulence factors of the bacteria?
capsules, pili, Iga protease production, iron capturing, production of coagulase and toxins, survival inside phagocytic cells
what are degrees of resistance of the host?
age, gender, physical and mental health, antibiotic therapy
what are lactoferrin binding proteins?
host iron binding proteins that bacteria scavenge iron from
what do Rec A proteins do?
exchange homologous dna sequences
what do chaperonins do?
help bacteria cope with stress
what do detoxification proteins do
play a role in virulence by protecting bacteria from oxidative damage
transposase use?
used in cut and paste and replicative transposition
tn5 (composite)
bacterial cut and paste transposons
what are the caveats of the transposon mutant screen?
no phenotypes if redunancy and cannot recover essential genes
what do M proteins help with?
virulence factors that help with attachment to various cells
how does TCR work?
- ligand induced receptor dimerization of TCR/CD3
- phosphorylation of the receptor ITAMs by Src family protein tyrosine kinases
- phosphorylated ITAMs act as a membrane docking site for ZAP-70
- ZAP-70 activate other proteins such as LAT that can recruit other proteins into the raft and further amplify the signal
- cytosolic kinase Csk bind to raft associated protein CBP and then inactivate the Src family kinases through phosphorylation
what are some professional phagocytes?
in blood: neutrophils and monocytes
in bone marrow: macrophages, monocytes, sinuisodal cells, lining cells
guts: macrophages
skin: langerhan cells, dendritic cells, macrophages, and mast cells
what are some non professional cells/
lymphocytes, fibroblasts and erythrocytes
what does C5a do?
act as chemoattractants to attract phagocyte to organisms to be ingested
what does C3b do?
coats organisms
what do Rho GTPases control?
phagocytosis required by actin rearrangements and pseudopod extensions
what are cell barriers in innate system
macrophages, neutrophils, amd NK cells
what are the three functions that innate immune receptors mediate
phagocytic receptors stimulate pathogen upatake
chemotactic receptors guide phagocytes to infection
stimulate production of effector cells and cytokines that influence innate and adaptive responses
what does vasodilation of capillaries do?
causes redness of tissue, increase tissue temp and capillary permeability, influx of fluids and phagocytes into tissues
what are the leukocyte players of innate responses?
neutrophils, macrophages, dendritic cells and NK cells
activation of what results in production what kind of cytokines?
activation of TLR, NLR,and RIG-I lead to TNF-a, IFNab, and IL-1b
what does TNFa do
activates macrophage and PMN phagocytosis and killing
what does IFNab activate
anti viral mechanisms
what does IL-1 do
stimulates inflammation and fever
what does immune IFN do
aka ifn y, big for adaptive immunity, made by t and nk cells, only one member, part of type II ifn
what does fibroblast ifn do
aka ifn b, very potent, made by all cells, only one member part of type I ifn, induce resistance to virus
what does leukocyte ifns do
aka ifn a, most prevalent, made by all cells, more than 10 members, part of type 1 ifn, induce resistance to virus
what is the lectin activation pathway for complement system
binding of mannose binding lectin
what is the overview of the complement activation
- C3 proteins cleave into C3a and C3b
- C3b reacts with amino and hyrdoxyl groups found on bacteria surfaces
- complement protein B binds to cell surface bound C3b, then protein D cleaves B to get more C3bBb
- C3bBb cleaves other C3 proteins to get more C3b to bind to invader
- C3bBb also cleaves C5 into C5b and combines with C6,7,8,and 9 to make membrane attack complex
- C9 forms a channel to open hole in invader and lyse it
process of making t cells
in thymus
- t cell progenitors make thymocytes with different t cell receptor
- thymocytes positively selected by epithelial cells in cortex of thymus
- positively chosen thymocytes divide
- thymocytes are then negatively selected in thymus medulla
- clones surviving leave thymus for circulation
what two receptors recognize lps?
TLR4 and CD14
what does furin do?
helps with proteolytic cleavage of dip. toxin
what are the properties of type 1 gram negative secretion?
- consists of three protein subunits: ABC protein, membrane fusion protein (MFP), and the outer membrane protein (OMP)
- ATP binding cassette transporter
- single step for traversing across CM and Om
- ABC channel- 6-12 transmembrane helices
- accessory factor- bridges periplasmic space
- coordinates synthesis
what are the steps for type II secretion?
Step 1: transfer across cytoplasmic membrane
1. leader peptide binds with SecA and inserts in CM channel that requires ATP
2. SecB is a cytosolic chaperone that keeps unfolded
3. SecYEG- cm channel complex
Step 2: transfer through periplasm/outer membrane transfer
1. protein folded into final structure and complex
2. signal peptide removal
3. chaperone mediated protein folding
4. disulfide bond formation
5. oligomerization
6. proline isomerization
what is type 3 secretion?
bacterial contact with host cell, coordinately induces regulatory, structural and effector genes encoded on a PAI, no sec dependence, provides a conduit for the direct translocation of bacterial proteins into host cells,
what is type 4 secretion?
- capable of transporting both proteins and DNA
- can translocate directly into host cell
- show homology to pilus mediated conjugal transfer systems
- sec like dependent translocation into periplasm
- B11 related to ATP-ases of type II
- D4 is DNA binding, may function in DNA transfer
- B6,B7, B8, B9, B10- core periplasmic components
- B2 and B5 are pilus components
differences between positive and negative secretions?
type III is oligolysin dep. translocation
type 4 is none
type 5 is b pore forming domain
