Bdellovibrio ppt

1. Welcome

2. Bdellovibrio

3.  Bdellovibrio was first time described by Stolp &
Starr in 1963.
 Bdellovibrio are-
 Gram negative
 Curved bacilli
 Exist independently
 Rod shape
 Single flagella
 Parasite against gram negative bacteria

4. Structure of Bdellovibrio

5.  Found in the ocean and fresh water
 6°C to 37°C
 Chemoheterotroph
 Also found in land habitats and the intestines of
mammals
 Eat gram negative bacteria that often cause
disease in plants, animals, and humans
 It is both aerobic and anaerobic but it works
faster in an aerobic environment

6.  Two phases of life, attack stage and growth stage
 Very small 0.2 to 0.5 micrometers x 0.5 to 1.4
micrometers
 Can move 100 cell lengths per second
 Grows inside the prey cell and can increase its
length up to 20 times
 Cell then bursts and the cycle repeats

7.  Target of attack on prey outer cell membrane
 No known mechanisms of resistance in prey
 Likely target is either non-specific or highly
conserved receptor necessary for cell
viability
 Subject of intense research as exact target has
been naturally selected as a favorable
strategy and may lead to development of
novel antibiotics

9.  Bdellovibrio uses flagella to make physical
contact, grabs on with pili
 Attachment is initially reversible, becomes
permanent after initial “recognition” step
 May have preferred prey – attachment rates differ
in mixed populations
 Enters through hole induced in outer
membrane by peptidoglycan hydrolysis

11.  Movement by a cell or organism in reaction
to a chemical stimulous
 Bdellovibrio genome contains 18 known
chemotaxis genes and 1 known aerotaxis
genes
 Chemotaxis likely used to find environments
favorable to prey species
 Quorum sensing signals are not utilized

12.  Bdellovibrio estabilizes prey outer membrane to
contain nutrients and protect against dehydration
 Bdellovibrio attaches to the inner membrane
causing the cytoplasm to round up into the
osmotically stable Bdelloplast
 Exact mechanism of Bdelloplast formation
is unknown but prey membrane maintains
structural integrity
 Bdellovibrio begins to extract and digest
prey cellular components

13.  Used to fight food borne illness and can destroy
90% of an E. Coli colony in an hour
 Bore into the prey cell at over 100 rotations per
second

14.  Biological control of pathogens.It is microbial
predator which attacks Xanthomonas ,
Pseudomonas etc.
 Water purification
 Biofilm (an aggregate of microbes) control
Disadvantages
 They might be deleterious to the plant growth
promoting rhizobacteria (PGPR)

15. Thankyou