Ecological adaptation of the Persian Gulf polychaete in a polluted area: proteomics concerning dominant defensive biomarkers

Marine species are negatively affected by wastewater. Based on our field observation along the Persian Gulf coastal areas, a widespread colony of polychaete worms , Galeolaria sp. lived in an area polluted with municipal wastewater. Accordingly, we hypothesized that a probable ecological adaption to bacterial pollutants has occurred. To test this hypothesis, protein profiling of coelomic fluid in the polychaetes collected from polluted and non-polluted areas was compared by RP-HPLC and 2DE, followed by MALDI-TOF analyses. The identical spots were selected as biomarkers, and the function of those proteins was determined by searching in databases in order to annotate their homologs using bioinformatics analyses by BLASTP, InterPro, PROSITE, Panther, and CDD servers. Twenty six and 17 HPLC fractions were extracted from the samples of polluted and non-polluted areas, respectively. Bacterial load in the water of polluted area was 2.8-fold higher than non-polluted area. The protein content of the samples of polluted area (3.65 µg/µL) was significantly greater than the samples of non-polluted (2.50 µg/µL) ones. MDS analysis of the HPLC profiles discriminated molecular pattern of polluted and non-polluted samples. Quantitative analysis of 2-DE results showed 65 and 23 spots in the polluted and non-polluted areas, respectively. Homology analyses of the peptide fragments derived from three biomarkers in the samples from polluted area, respectively, showed similarity with keratin, cyanelle 30S ribosomal protein, and peptidyl-prolyl isomerase, suggesting a reaction against bacterial pollution. The dominant biomarkers confirmed that probably a conditional adaptation has been happened in the polychaetes lived in the polluted area.