Effects of atrazine, agricultural runoff, and selected effluents on antimicrobial activity of skin peptides in Xenopus laevis

• Published in: Ecotoxicology and environmental safety 2011-05, Vol.74 (4), p.593-599
• Main Authors: Gibble, R.E., Baer, K.N.
• Format: Article
• Language: English
• Subjects: Agricultural management; agricultural runoff; Agriculture; Agronomy. Soil science and plant productions; Amphibian; amphibians; Animal, plant and microbial ecology; Animals; Antifungal Agents - toxicity; Antimicrobial peptides; antimicrobial properties; Applied ecology; Atrazine; Atrazine - metabolism; Atrazine - toxicity; Batrachochytrium dendrobatidis; Biochemistry; Biological and medical sciences; chronic exposure; Chytrid fungus; Chytridiomycota - drug effects; Ecotoxicology, biological effects of pollution; Effluents; exposure models; Fresh Water - chemistry; Fundamental and applied biological sciences. Psychology; Fungi; General agroecology; General agroecology. Agricultural and farming systems. Agricultural development. Rural area planning. Landscaping; General agronomy. Plant production; General aspects; Generalities. Agricultural and farming systems. Agricultural development; hydrologic models; immunity; landfills; larvae; mortality; pathogens; Peptides; Peptides - toxicity; protein content; Proteins; Runoff; secretion; sewage effluent; sewage treatment; Skin - secretion; Water Pollutants, Chemical - toxicity; Xenopus laevis; Xenopus laevis - immunology; Xenopus laevis - physiology; Xenopus Proteins - metabolism
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2010.11.009

Atrazine (technical and formulation), agricultural runoff containing atrazine, and treated sewage and landfill effluents were evaluated for their potential to modulate antimicrobial activity of Xenopus laevis skin secretions against the chytrid fungus, Batrachochytrium dendrobatidis. This chytrid fungus is implicated in several localized mass mortality events, yet the cause of the susceptibility of amphibians to this newly emergent pathogen is unknown. Antimicrobial peptides secreted from dermal glands are thought to provide critical protection against this pathogen. Chronic exposure of X. laevis larvae to agricultural runoff decreased protein content of collected secretions, while treated wastewater effluents increased protein content. However, the in vitro bioactivity was decreased in treatments with both increased and decreased protein. No differences were observed in protein or bioactivity following laboratory exposures of technical atrazine or a typical atrazine formulation (AAtrex ® 4L/Top Surf ®). These findings demonstrate that exposure of an amphibian model to agricultural runoff or effluent from municipal sewage treatment plants and landfills alters peptide production and in vitro activity of protective peptides. Although evidence suggests peptide production and bioactivity is a critical part of amphibian resistance to pathogens such as the chytrid fungus, the implications of observed effects for immunity and infection are not clear.