Bacterial Secretion Systems Flashcards
How are virulence factors used to infect the host
many virulence factors have to be delivered directly into a host cell to potentiate the activity and cannot benefit the bacteria without a delivery mechanism
Is the delivery system of virulence factors more complex in gram - or gram + and why
gram - bacteria have a more complex delivery systems because of their envelope structure
What types of sec systems are used by gram - systems
sec dependent
type 2 and 5
What types are sec dependent systems
type 2 and 5
used by gram -
What types are sec independent
type 1, 3, 4, 6
How do Type II secretion systems work (T2SS)
secretes some A-B toxins such as in Cholera and ExoA
- uses the general secretory or twin arginine system to reach the periplasm
- they pass through the pore formed by twelve to fourteen proteins
- mechanism similar to pilin secretion
- cholera toxin is secreted by type II
What type of secretion system is used to release the cholera toxin
secretes cholera A-B toxin
also used for ExoA
Type II, which is sec-dependent
How do Type V secretion systems work (T5SS) what are some examples
referred to as the auto transporter system
IgA Protease
VacA
Pertactin: highly immunogenic virulence factor of Bordetella pertussis
sec dependent
What type of secretion system is used to release pertactin, VacA, or IgA proteases
type V
sec dependent
What secretion system is referred to as the auto transporter system
type V secretion system
sec dependent
How do Type I secretion systems work (T1SS) what are some examples
consists of three components
- inner membrane transporter
- periplasmic connector
- outer membrane pore
can export proteins up to 800 kDa
Efflux pumps
common in E. coli Hemolysin Hly
What secretion system are efflux pumps considered
considered type I
sec independent
What type of secretion system has three components including inner membrane transporter, periplasmic connector and an outer membrane pore
type I
sec independent
How do Type III secretion systems work (T3SS) what are some examples
consists of over 20 proteins
on contact it injects toxins into the host eukaryotic cell
similar structure to the flagella
present in many human, animal and plant pathogens
commonly encoded on MGEs: plasmids, pathogenicity islands
E. Coli Salmonella Shigella Yersinia Bordetella Pseudomonas Chlyamydia
What type of secretion systems are common in present in many human, animal and plant pathogens and that are commonly encoded on MGEs: plasmids, pathogenicity islands
type III
sec independent
What type of secretion system on contact injects toxins into the host eukaryotic cell
type III
sec independent
What type of secretion system is similar in structure to the flagellum
type III
sec independent
How do Type IV secretion systems work (T4SS) what are some examples
can inject proteins or DNA into a host cell
similar to horizontal gene transfer systems
sec independent
requires 12 protein complex
associated with MGES: plasmids and PAIs
VirD4: ATPase, just inner membrane
IMC: inner membrane complex of VirB3,4,6,7,8,11, just inner membrane
OMC: outer membrane complex of VirB7, 9, 10, outer and inner membrane
Pilus component: Vir B2 and B5 tip, through the outer and inner membrane
first discovered in agrobacterium tumefaciens
other pathogens include:
Helicobacter Legionella Coxiella Brucella Bartonella Rickettsia Bordetella
What type of secretion system is similar to horizontal gene transfer
type IV secretion system
sec independent
What type of secretion system was first discovered in agrobacterium tuefacienes
type IV secretion system
sec independent
What type of secretion system is often associated with MGE also with plasmids and pathogenicity islands
Type IV
sec independent
How do Type VI secretion systems work (T6SS) what are some examples
most recently discovered in gram - systems
appears to function similarly to the contraction of the phage sheath
useful for microbial competition, they use it to duel with one another
What type of secretion system is often associated with appears to function similarly to the contraction of the phage sheath
type VI
sec independent
What type of secretion system is often associated with microbial competition by dueling with one another
Type VI, sec independent
useful for microbial competition, they use it to duel with one another
What secretion systems do gram + bacteria use
sec independent:
Type VII secretion system that is adapted for mycobacteria
sec dependent:
different arrangements of sec A-Sec YEG transporter
sortase system
accesstory sec system
cytolysin mediated translocation CMT q
