| Popis: |
In recent years, parasites are increasingly used as bioindicators of environmental quality [1]. Acanthocephala, also known as thorny-headed worms, are proving to be particularly sensitive indicators of metal pollution in ecotoxicological studies of aquatic ecosystems. They are obligate endoparasites that in the adult stage live in the intestines of vertebrates and take up nutrients from the intestinal lumen of their host. Acanthocephalans can absorb toxic metals more efficiently than other commonly used aquatic bioindicators, such as fish, crustaceans, and bivalves [2]. However, the mechanism of metal homeostasis and accumulation in acanthocephalans is still unexplained. Therefore, we investigated the effects of in vitro Cd2+ exposure on metal accumulation and gene expression in Dentitruncus truttae Sinzar, 1955, hosted in brown trout (Salmo trutta Linnaeus, 1758) from the Krka River. Parasites were exposed to 2 and 10 mg Cd2+ l-1 in culture for 3 and 5 days, and Cd2+ levels in the organisms were determined using HR ICP-MS. Next- generation RNA-Seq technology was used to investigate genome-wide differentially expressed gene profiles between control and Cd2+-treated acanthocephalan specimens. Our study confirmed the ability of these parasites to accumulate high metal concentrations. When exposed to 10 mg Cd2+ l-1, they accumulated 188.6 mg Cd2+ g-1 after three days and 267 mg Cd2+ g-1 after five days. Exposure to these high concentrations resulted in significantly different gene expression compared to the control. At a Cd2+ dose of 2 mg l-1, a total of 4826 differentially expressed genes (DEGs) were detected (predominantly down- regulated), whereas at a dose of 10 mg l-1, 5809 DEGs were detected (predominantly up-regulated). The most enriched biological processes included: protein digestion and absorption, gap junction, focal adhesion, apoptosis, and genes related to infection and disease. Understanding the process by which acanthocephalans accumulate metals could be important in assessing environmental metal exposure and explaining the response of the infected vertebrate host, so Environmental Parasitology represents an important novel research field. |
