Variation in Predation Phenotype among Predatory Bacteria Bdellovibrio
Authors: Martinez Karla , Oser Molly , Williams Laura E. 
Published: June 2021

Bdellovibrio are Deltaproteobacteria that attack and digest other bacteria. They are the most well studied predatory bacteria and inhabit soil and freshwater environments. Bdellovibrio attack Gram‐negative pathogens, which makes them good candidates for biocontrol agents or alternatives to antibiotics.

Many studies of Bdellovibrio focus on the type strain HD100, which provides an important foundation for understanding the molecular biology of these predatory bacteria. To build on this foundation and explore variation in phenotype among Bdellovibrio, we isolated Bdellovibrio sp. NC01 from a soil sample taken from a bioswale, which is an artificial landscape feature on the Providence College campus that collects and filters stormwater runoff from nearby buildings. We investigated whether NC01 and HD100 differ in how quickly or effectively they attack particular prey bacteria (predation efficiency) and whether the two strains attack the same prey strains (prey range).

In comparison to type strain HD100, NC01 appeared less aggressive in lysates, taking longer to attack prey cells and multiply. On a double agar overlay plate, NC01 was slower to form plaques and, in contrast to HD100, plaques of NC01 were not completely clear. To quantify the rates of predation, we performed a predation efficiency assay, which assessed the cfu/ml of viable E. coli ML35 over at least 48 hours in the presence of either NC01 or HD100. Preliminary data supports our qualitative observations that HD100 is a far more aggressive predator than NC01. At 24 hours, HD100 had eliminated almost all viable E. coli. By contrast, predation by NC01 resulted in a less drastic decrease in viable E. coli at 24 hours, and, at 48 hours, viable E. coli actually increased even though active predatory bacteria were still present. We did not observe recovery of the E. coli population in lysates with HD100. Currently, we are completing replicates to confirm this trend and exploring possible explanations.

To compare the prey range of NC01 and HD100, we challenged them with six different prey bacteria isolated from soil and freshwater environments and two E. coli strains. Preliminary data suggests that NC01 and HD100 have the same prey range profile, forming plaques on prey lawns of five of the eight prey bacteria tested. Currently, we are confirming our preliminary data with additional prey range test replicates of HD100.

Moving forward, we are sequencing the genome of Bdellovibrio sp. NC01 to understand how genotypic variation correlates with the variation in predation efficiency observed here. This work contributes to our knowledge of overall diversity in Bdellovibrio, which may be useful for developing these predatory bacteria as biocontrol agents.

Support or Funding Information

Research reported in this poster was supported by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under grant number 2 P20 GM103430 and startup funding from Providence College.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.