Event Title

Battle of the Biotics: Inhibition of the Amphibian Chytrid Fungus using Biotic and Abiotic factors

Location

Alumni Hall South

Department

Biology

Abstract

Batrachochytrium dendrobatidis, the amphibian chytrid fungus known as Bd, is one of the greatest threats facing amphibian species. Chytrid has been the leading cause of frog deaths in the rainforests of Australia and Panama since it was first described in 1997. The chytrid fungus is also associated with the rapid decline of frog populations in Ecuador, Venezuela, New Zealand, and Spain. The disease associated with chytrid fungus, chytridiomycosis, is fatal in post-metamorphic frogs and can be transmitted to young tadpoles when zoospores are released into the streams or rivers inhabited by the tadpoles. With this in mind, we know that the chytrid fungus is an amphibian generalist, meaning it is not limited to only frog deaths, but can also be linked to other amphibian deaths such as salamanders and newts. The chytrid fungus can also infect various life stages of amphibians making it difficult to know where to target our efforts for treatment. In this study, four different soil dwelling Bacillus species that have some antifungal properties, were used to determine if they also inhibit the infective Bd zoospore stage. Each Bacillus species was cultured in BHI broth and the conditioned supernatant was used in a standard disc diffusion assay with a 1% tryptone plate that has been inoculated with Bd zoospores. Bacillus thuringiensis showed the most constancy in producing a zone of inhibition on the 1% tryptone plate in preliminary testing. In addition, abiotic factors related to global warming and modern farming practices (temperature and compounds found in common fertilizers) were tested. To test temperature, zoospores were incubated from 21-29 degrees C for 12 days, and live counts were assessed at days 4, 8, and 12. The zoospores grown at 29°C had the lowest percentage of survival in preliminary testing. Future work consists of exposing zoospores to common fertilizer components as well as widening the temperature range, and to continue the disc diffusion assay for the Bacillus spp. to see if additional Bacillus species can also produce a zone of inhibition.

Faculty Sponsor

Emily Rumschlag-Booms, Northeastern Illinois University

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May 6th, 11:40 AM

Battle of the Biotics: Inhibition of the Amphibian Chytrid Fungus using Biotic and Abiotic factors

Alumni Hall South

Batrachochytrium dendrobatidis, the amphibian chytrid fungus known as Bd, is one of the greatest threats facing amphibian species. Chytrid has been the leading cause of frog deaths in the rainforests of Australia and Panama since it was first described in 1997. The chytrid fungus is also associated with the rapid decline of frog populations in Ecuador, Venezuela, New Zealand, and Spain. The disease associated with chytrid fungus, chytridiomycosis, is fatal in post-metamorphic frogs and can be transmitted to young tadpoles when zoospores are released into the streams or rivers inhabited by the tadpoles. With this in mind, we know that the chytrid fungus is an amphibian generalist, meaning it is not limited to only frog deaths, but can also be linked to other amphibian deaths such as salamanders and newts. The chytrid fungus can also infect various life stages of amphibians making it difficult to know where to target our efforts for treatment. In this study, four different soil dwelling Bacillus species that have some antifungal properties, were used to determine if they also inhibit the infective Bd zoospore stage. Each Bacillus species was cultured in BHI broth and the conditioned supernatant was used in a standard disc diffusion assay with a 1% tryptone plate that has been inoculated with Bd zoospores. Bacillus thuringiensis showed the most constancy in producing a zone of inhibition on the 1% tryptone plate in preliminary testing. In addition, abiotic factors related to global warming and modern farming practices (temperature and compounds found in common fertilizers) were tested. To test temperature, zoospores were incubated from 21-29 degrees C for 12 days, and live counts were assessed at days 4, 8, and 12. The zoospores grown at 29°C had the lowest percentage of survival in preliminary testing. Future work consists of exposing zoospores to common fertilizer components as well as widening the temperature range, and to continue the disc diffusion assay for the Bacillus spp. to see if additional Bacillus species can also produce a zone of inhibition.