Stevick_R_27November_2017 |
Stevick_R_27November_2017
Graduate School of Oceanography - OCG 695
27 November, 3:30 PM, Coastal Institute Auditorium
27 November, 3:30 PM, Coastal Institute Auditorium
Probiotic-Driven Changes in Microbial Communities in an Oyster Hatchery
Larval oysters in hatcheries are susceptible to diseases caused by marine bacterial pathogens, including Vibrio spp. These diseases can be prevented by daily addition of probiotics like Bacilus pumilus RI06-95 to water in rearing tanks. We propose that the presence of probiotics may change how the larvae respond to pathogens, regulate their environment, and recruit beneficial microbes. During three separate trials spanning the 2012-2015 growing seasons, rearing water samples (<2 liters) were collected from control and probiotic-treated tanks in an oyster hatchery at timepoints between Day 0 (spawning) and Day 12. Water samples were filtered onto 0.22 μm Sterivex filters and DNA was extracted directly from the filters, then prepared for sequencing. All tanks were analyzed using 16S rDNA sequencing of the V3-V4 or V6 regions and direct taxonomic classification, in order to determine microbial community structures. Overall, there was a significant effect of time, but no major effect of probiotics on the rearing water bacterial communities (Bray-Curtis k=2, 95% confidence). However, the presence of a higher proportion of Oceanospirillales spp. and Bacillus spp. was detected in the treated tanks. Co-occurrence network analysis suggests that the probiotic effect on the rearing water is mediated through select associated taxa. The results of this project will inform interactions between probiotics and microbial communities in oyster hatcheries, and how new probiotics may be designed.
Rebecca Stevick earned a B.S in Bioengineering from the University of Maryland in 2015. She enrolled in the PhD program at GSO in fall 2015. Her co-major professors are Dr. Anton Post and Dr. Marta Gómez-Chiarri.
Larval oysters in hatcheries are susceptible to diseases caused by marine bacterial pathogens, including Vibrio spp. These diseases can be prevented by daily addition of probiotics like Bacilus pumilus RI06-95 to water in rearing tanks. We propose that the presence of probiotics may change how the larvae respond to pathogens, regulate their environment, and recruit beneficial microbes. During three separate trials spanning the 2012-2015 growing seasons, rearing water samples (<2 liters) were collected from control and probiotic-treated tanks in an oyster hatchery at timepoints between Day 0 (spawning) and Day 12. Water samples were filtered onto 0.22 μm Sterivex filters and DNA was extracted directly from the filters, then prepared for sequencing. All tanks were analyzed using 16S rDNA sequencing of the V3-V4 or V6 regions and direct taxonomic classification, in order to determine microbial community structures. Overall, there was a significant effect of time, but no major effect of probiotics on the rearing water bacterial communities (Bray-Curtis k=2, 95% confidence). However, the presence of a higher proportion of Oceanospirillales spp. and Bacillus spp. was detected in the treated tanks. Co-occurrence network analysis suggests that the probiotic effect on the rearing water is mediated through select associated taxa. The results of this project will inform interactions between probiotics and microbial communities in oyster hatcheries, and how new probiotics may be designed.
Rebecca Stevick earned a B.S in Bioengineering from the University of Maryland in 2015. She enrolled in the PhD program at GSO in fall 2015. Her co-major professors are Dr. Anton Post and Dr. Marta Gómez-Chiarri.