Bacteria Flashcards
What makes up prokaryotes?
Bacteria and archaea
What are planctomycetes
True compartmentalisation
DNA is surrounded by a double lipid bilayer
true bacteria that contain a nuclear envelope
Magnetosomes
crystals of an iron mineral which is known as a compass
Present in numerous bacteria
What organises the magneto some chain?
MamK
What is MamK
Actin like protein that forms filaments in the prokaryote cytoskeleton
Organelle assembly
Name protein filaments in prokaryotes
AlfA, ParM, actin and MamK
Describe prokaryotic actin
same fold by only identify between MreB and eukaryotic actin, both bind ATP and polymerise
Describe MreB
Cell shape, prokaryotes
Describe ParM
DNA partitioning, prokaryotes
Plasmid segregation
Binds ATP
Dynamic
Which protein filaments are involved in bacterial morphogenesis?
MreB and Mdl1
FtsZ
tubules homologue, GTPase activity, formation of protofilaments, similar folds
Cleaving bacteria
Cell separation
Modes of motility
swimming, swarming, gliding and twitching
What is swarming?
occurs on surfaces
What are flagella?
protein assemblies that rotate, motility is driven by a basal motor that uses a protein gradient
switch in direction
What is gliding?
Surface attached motility
Various mechanisms that were independently developed
Some cells rotate over secreted adhesion proteins
Secretion based
What is twitching?
Pili based
secretion or degradation changes length of the type
Change in length can be used for slow gliding over surfaces
Twitching motility used to form colonies
Extended and retracted
Structure of pili
Thin polymers on one protein (pilin)
What is moving the cells
During movement, bacteria form a tail at their rear end, the tail consists of fibres which is f-actin
Bacteria is able to polymerise its G actin into F actin in the tail moving it forward
How can we prove that bacteria use the host actin to move in the host cytosol?
use G actin and label it with GFP and put it with bacteria in a test tube, if its G actin you should see green tails and movement
What mediate motility in bacteria?
ActA
What is the life cycle of a cytosolic bacterium
Engulfment, proliferation and motility
Type 3 and type 6 secretion system
Injects proteins
Type 3 secretion
Similar proteins with prokaryotic flagellum
Rings of proteins assemble into a needle, channel
Send effectors through the secretion system into the needs and can control things like the cytoskeleton
