Event Title

Does the Presence of the Marine Zooplankton Brachionus Plicatilis Influence Bacteriophage Abundance?

Faculty Advisor

William Jaeckle

Graduation Year

2019

Location

Center for Natural Sciences, Illinois Wesleyan University

Start Date

21-4-2018 9:00 AM

End Date

21-4-2018 10:00 AM

Description

Bacteriophages (phages) are the most abundant organisms on Earth and exist in concentrations exceeding 107 phage/mL in aquatic environments (Clokie et al., 2011). Though abiotic factors (e.g., UV radiation) are mainly responsible for phage loss in these environments, consumption by single-celled protists also contributes to phage abundance. Straznikas and Jaeckle (2017) reported that the rotifer Brachionus plicatilis ingests phages as food, but the degree to which multicellular, filter-feeding zooplankton influence phage abundance is unknown. We investigated the effect of rotifer feeding on the concentration of phages, hypothesizing that rotifers significantly reduce the abundance of phage. Bacteriophages (Rc-Titan, 108 phage / mL in 10 mL of filtered seawater) were exposed to rotifers (10 / mL) and Nannochloropsis sp. (food for rotifers, 106 / mL), Nannochloropsis sp. alone (106 / mL), or filtered seawater to account for all potential causes of phage loss; each treatment was replicated 3´. Every 2-3 days over a 9-day incubation, 100 µL samples were collected from each vial and the concentration of phages in each sample measured. In all treatments, the concentration of bacteriophages decreased over the incubation period, and on day 9 there was a significant difference (F(2,6) = 464.1, p < 0.001) in the concentration of phages among the three treatments. The concentration of phages was lowest in the rotifer + Nannochloropsis treatment (2.17×105 ± 5.8×104 phage / mL), intermediate in the Nannochloropsis treatment (1.02×106 ± 3.6×104 phage / mL) and highest in the filtered seawater treatment (2.65×107 ± 1.2×106 phage / mL); all treatments were significantly different from one another (Gaines Howell, post hoc test, p < 0.02). Our preliminary results indicate that the presence of rotifers can significantly reduce the abundance of phages in aquatic environments.

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Apr 21st, 9:00 AM Apr 21st, 10:00 AM

Does the Presence of the Marine Zooplankton Brachionus Plicatilis Influence Bacteriophage Abundance?

Center for Natural Sciences, Illinois Wesleyan University

Bacteriophages (phages) are the most abundant organisms on Earth and exist in concentrations exceeding 107 phage/mL in aquatic environments (Clokie et al., 2011). Though abiotic factors (e.g., UV radiation) are mainly responsible for phage loss in these environments, consumption by single-celled protists also contributes to phage abundance. Straznikas and Jaeckle (2017) reported that the rotifer Brachionus plicatilis ingests phages as food, but the degree to which multicellular, filter-feeding zooplankton influence phage abundance is unknown. We investigated the effect of rotifer feeding on the concentration of phages, hypothesizing that rotifers significantly reduce the abundance of phage. Bacteriophages (Rc-Titan, 108 phage / mL in 10 mL of filtered seawater) were exposed to rotifers (10 / mL) and Nannochloropsis sp. (food for rotifers, 106 / mL), Nannochloropsis sp. alone (106 / mL), or filtered seawater to account for all potential causes of phage loss; each treatment was replicated 3´. Every 2-3 days over a 9-day incubation, 100 µL samples were collected from each vial and the concentration of phages in each sample measured. In all treatments, the concentration of bacteriophages decreased over the incubation period, and on day 9 there was a significant difference (F(2,6) = 464.1, p < 0.001) in the concentration of phages among the three treatments. The concentration of phages was lowest in the rotifer + Nannochloropsis treatment (2.17×105 ± 5.8×104 phage / mL), intermediate in the Nannochloropsis treatment (1.02×106 ± 3.6×104 phage / mL) and highest in the filtered seawater treatment (2.65×107 ± 1.2×106 phage / mL); all treatments were significantly different from one another (Gaines Howell, post hoc test, p < 0.02). Our preliminary results indicate that the presence of rotifers can significantly reduce the abundance of phages in aquatic environments.