Prey Range, Predation Efficiency, And Comparative Genomics of Bdellovibrio From the Same Soil Sample
Subject Area
Biology
Description
Brianna Harper ’22
Major: Biology
Faculty Mentor: Dr. Laura Williams, Biology
Predatory bacteria of the genus Bdellovibrio invade and digest Gram-negative bacteria in freshwater and soil environments. Bdellovibrio can attack animal and plant pathogens, including multi-resistant pathogens, making them a potential alternative to antibiotics. Bdellovibrio strains vary in predatory phenotypes such as prey range (which species are killed) and predation efficiency (how quickly and to what extent prey populations are killed). To investigate phenotypic and genomic variation in Bdellovibrio, we compare three Bdellovibrio isolates obtained from the same soil sample collected near a pond at a Rhode Island state park. We classified the isolates as Bdellovibrio sp. KM01, KM02, and KM03 and previously published the KM01 genome. To analyze prey range, we tested the three isolates’ ability to form plaques on lawns of eight Gram-negative bacteria, including four strains isolated from freshwater (Acinetobacter, Aeromonas, Enterobacteriaceae, Raoultella), two strains isolated from soil (Pseudomonas and Serratia), and two strains of E. coli. To analyze predation efficiency, we co-cultured each isolate with Raoultella and measured changes in optical density over 72 hours. For comparative genomics, we generated long-read and short-read data for KM03 and short-read data for KM02. In prey range tests, each of the three isolates formed plaques on the same four prey strains (E. coli ML35, Enterobacteriaceae, Raoultella, and Serratia). By contrast, previous data showed that B. bacteriovorus HD100 formed plaques on all eight prey strains and soil Bdellovibrio sp. NC01 formed plaques on five, overlapping only partially with the three isolates’ prey range. Results of predation efficiency assays show strong similarities among the three isolates. For co-cultures with a starting Bdellovibrio concentration of 1 x 107 pfu/ml and initial OD600 of 0.150, all three isolates reduced the Raoultella population to OD600 0.050 within 24 hours, then maintained this prey concentration over the next 48 hours. Preliminary genome comparisons indicate that KM01 and KM02 are almost identical, but KM03 differs. Moving forward, we will assess predation efficiency of the three isolates, HD100, and NC01 by testing them against different prey strains and using different initial prey concentrations. We will also generate genome sequences of KM02 and KM03 and examine gene content differences. Our study of the variation among these isolates will provide insight into the ecology and evolution of Bdellovibrio and may inform their development as biocontrol agents.
Publisher
Providence College
Date
4-28-2022
Type
Poster
Language
English
