JAN 05, 2016 06:28 PM PST

Better Know a Microbe: Bdellovibrio

WRITTEN BY: Kerry Evans
Bdellovibrio bacteriovorus is definitely the most terrifying bacterial species I’ve written about.  What sets Bdellovibrio apart from other pathogens is that it is quite literally a predator - like, alien hunting Arnold Schwarzenegger in the jungle, predator.
 
Bdellovibrio (right) preys on a larger cell.
Bdellovibrio bacteriovorus is a Gram-negative, motile, “comma-shaped” bacterium that was first described by Stolp and Petzold in 1962.  It is a rather ubiquitous organism, making its home in water, soil, and the mammalian GI tract.

A 2004 Science article breaks down the Bdellovibrio life cycle into eight (frightening) steps:
  1. Not only is Bdellovibrio motile, it is one of the fastest swimmers in the bacterial world, traveling 100 times its cell length every second.  During the initial “attack phase”, Bdellovibrio uses its single flagellum to swim towards its prey (the precise mechanism by which cells locate their prey is not well understood).  
  2. After making contact with its prey cell (other unsuspecting Gram-negative bacteria such as E. coli and Pseudomonas) it becomes permanently attached by the cell pole opposite its flagellum.  This attachment is probably facilitated by interactions between predator and prey lipopolysaccharide molecules and outer membrane proteins.
  3. At this point, things start to get ugly.  Bdellovibrio uses hydrolytic enzymes to make a small hole in the prey cell’s outer membrane and peptidoglycan.  It then uses that hole to gain access to the prey cell’s periplasm (the space between the outer and inner membranes, outside of the cytoplasm).
  4. Next, Bdellovibrio jump starts its DNA replication and cell division machinery so that it can divide.
  5. Now that Bdellovibrio is snugly situated inside its prey’s periplasm, it causes the prey cell to go from rod-shaped to rounded, forming what’s called a “bdelloplast”.  
  6. By this time, Bdellovibrio has worked up an appetite, so the predator cell siphons nutrients and ATP out of the prey’s cytoplasm.  The predator cell then grows into a long filament and eventually divides into daughter cells
  7. After division, the daughter cells develop flagella and use hydrolytic enzymes to degrade the prey cell’s outer membrane.
  8. Last, but not least, the new predator progeny cells are released from the prey cell to wreak further havoc (yikes).
Bdellovibrio life cycle

There is a lighter side to Bdellovibrio.  Some researchers think these cells can be used as “living antibiotics” to seek out and destroy infecting pathogens.  There has even been a trial to use Bdellovibrio to eradicate Salmonella enteridis from chicks.  The “treatment” reduced the number of Salmonella cells and caused no significant side effects in the birds when compared to a non-predatory mutant.  This is good news for the poultry industry, since it could cut down on the use of antibiotics and possibly curb the spread of antibiotic resistance.

Sources: Science, MicrobeWiki, Wikipedia, Applied and Environmental Microbiology
 
About the Author
  • Kerry received a doctorate in microbiology from the University of Arkansas for Medical Sciences.
You May Also Like
OCT 05, 2018
Microbiology
OCT 05, 2018
Reducing Pollution with Engineered Bacteria
A varsity of creative strategies have been proposed as solutions to climate change, from practical to outlandish....
OCT 09, 2018
Drug Discovery
OCT 09, 2018
'Copper Antibiotic Peptide' Effective in Eradicating Tuberculosis
The bacterium responsible for Tuberculosis has found a way to avoid antibiotics by hiding inside the macrophages which are the specific immune cells that a...
NOV 06, 2018
Videos
NOV 06, 2018
Towards a Universal Flu Vaccine
Researchers have to design a new flu vaccine every year. But there are efforts to create a vaccine that works against all strains....
NOV 19, 2018
Cell & Molecular Biology
NOV 19, 2018
How Mitochondria can Help the Cell Fight Pathogens
Some pathogens can get around out bodies' natural defense mechanisms. So our body developed a Plan B....
NOV 25, 2018
Microbiology
NOV 25, 2018
Researchers Learn How Hantavirus Infects Cells
First identified in 1993, hantavirus infections can cause dangerous and potentially deadly respiratory infections....
DEC 11, 2018
Genetics & Genomics
DEC 11, 2018
Dust with High Levels of Triclosan has More Antibiotic Resistance Genes
Researchers have found that some dust contains high amounts of a common antimicrobial agent called triclosan....
Loading Comments...