L27+30 Flashcards
What is bdellevibrio, break up the name, the behaviour, morphology and isolation
a parasite
bdell = leech
vibiro = curved
morphology: G(-) deltaproteobacteria, aerobic, obligate parasite
behaviour: parasitises other G(-) cells + uses fungal hypae highways
WT is unculturable but mutants were isolated while trying to culture bacteriophage
Where does bdellvibrio live
soil, freshwater, marine, biofilm, sewage
What is the life cycle of bdellovibrio
takes many hours
1. attack phase
2. protein synthesis and enzyme secretion
3. growth phase
4. cell division
What happens during the attack phase
- cell swims at 100cells/second and impacts the host
- attaches and interacts with the outer membrane
- twists to enter the periplasm
- detaches flagella
(takes 5-10 minutes)
What is step 2 of bdellvibrio life cycle
protein synthesis and enzyme secretion
1. murmaidase, lactase, glycanase
=> breaks down host cell wall and lipids to form bdelloplasts which are osmotically stable
- protease, peptidase, nucelase
=> degrade host cell protein, DNA and RNA - PORE PROTEIN OMPF
=> insrted into membrane to flow nutrients out of the house
SYNTHESIZES TRANSPORT PROTEINS
=> only in te cytoplasmic membrane for uptake of host nutrients
Explain Growth and cell division of bdellovibrio
GROWTH
1. absorbs the host nutrients and it grows without division
2. aquires lipids from the cell
3. cannot synthesize amino acids, so depends on contact with the host to initiate DNA replication
CELL DIVISION
1. large Bdellovibrios cell divides into small cells like a link of sausages
2. host cell lyses
3. bdellovibio progeny esacpe
What did genetics analysis of bdellovirbio reveal
- genome was sequenced but no evidence of gene transfer from the host, no quorom sensing
- noted many attacking and consuming genes (for the enzymes/proteins)
- capable of generating energy via TCA cycle AND can synthesise own DNA/translate without host help
- can only synthesis 11 a.a genes by itself, and missing 10 a.a degradation genes
What are some uses of bdellovibrio big negative
control G(-) bacteria for example
E coli in food
biocontrol of plant pathogens
eye/lung pathogens
Has issues with biofilms or anything that prevents them from hitting prey
What is myxobacteria, morphology, behaviour, isolation
G(-) deltabacteria
model species is myxococcus xanthus meaning golden slime berries
behaviour they assimilate nutrients heterotrophically or prey on other cells
behaviour: moves via gliding/social motility
isolated: from fruiting bodies via dung isolation
Explain three types of movement of myxococcus
social motitliy: movement in groups, dependant on cell to cell contact facilitated by pili so it can spread in multicellular packs
fruiting body: when nutrients are scarce its forms fruiting bodies which are multicellular bodies that allowed bacteria to move. many cells aggregate and pile into mounds, were some become dormant and resists harsh conditions then after when conditions are better they can germinate and reestablish bacterial colony
adventurous motility: movement of individual cells, can move across trough slime secretion so it can explore new areas with suitable conditions
What are myxobacteria habitats, and habitat preferences
soil, herbivore dung, decaying wood, freshwater
places with fierce competition
neutral pH range, mesophilic, but can stay in extremes
has a very global range: antarctic tropical desert…
What did genetic investigation on myxobacteria reveal
have multicellular life cycle with developmental genes, gene regulation, many types of cell-cell communication
so it can be used in biotechnology
very large 9.14mb genome
What is cooperative predation in m. xanthus
group predation => signal transduction => extracellular digestion with enzymes => nutrient uptake
What are the main steps in myxobacteria life cycle
a. vegetative cells + predation
b. fruiting body formation
What is vegetative cell predation in myxobacteria, relate to []
the vegegative cells are heterotrophic or predatory they team up with other cells via qourom sensing to digest macromolecules cellulose or to prey on other bacteria
bigger quorums = more exoenzymes (same ones as bdellovirio)
they swarm and assimilate in waves
