Protein biomarkers as indicator for water pollution in some lagoons of Sardinia (Italy)

1 - Studying the expressed proteome in mussel tissues is important to understand many different biological, physiological and ecological aspects that may be of advantage in shellfish rearing, encompassing growth cycle, food safety and traceability as well as understanding the biological effects of environmental pollution and climate change. 2 - The present work attempted to accomplish a systematic characterization of the foot muscle proteome of M. galloprovincialis, to gather data about its variability in physiological conditions occurring in different environments of mussel rearing and to identify a putative set of protein biomarkers that may be significantly correlated to environmental factors. 3 - A total of 360 mussels were sampled from three different lagoons of Sardinia, each one characterized by its different environmental and ecological system. According to a double latin square design, a smaller subgroup of 54 mussels that was representative of the original population was submitted to proteomics analysis and trace metals quantification. Classical and multivariate statistics was performed to correlate protein expression data to trace metal content and to environmental parameters recorded in situ. 4 - A protein expression pattern of 79 protein was identified as related to the response to environmental stressors like dissolved oxygen, water acidity, temperature and trace metals. 5 - The identified proteins are cytoskeletal proteins (α-tubulin, β-tubulin, myosin light chains and tropomyosin) or are involved in metabolic pathways (fructose bisphosphate aldolase), in energy pathways (cytosolic malate dehydrogenase and arginine kinase), in antioxidant defense (protein disulfide isomerase) and in protein turnover (different isoforms of the heat shock proteins Hsp70 and Hsc71); also the histone protein H2B is reported. 6 - Our preliminary results show that there is correlation between the expressed protein pattern and the environmental conditions, confirming the findings of other proteomics works carried out on different mussel tissues and other marine invertebrates. Further validation procedures of the identified correlations must be accomplished in order to regard the identified proteins as biomarkers for environmental pollution and climate change.