Transcriptional Response of the Mussel Mytilus galloprovincialis (Lam.) following Exposure to Heat Stress and Copper

Abstract

Global warming is a major factor that may affect biological organization, especially in marine ecosystems and in coastal areas that are particularly subject to anthropogenic pollution. We evaluated the effects of simultaneous changes in temperature and copper concentrations on lysosomal membrane stability (N-acetyl-hexosaminidase activity) and malondialdehyde accumulation (MDA) in the gill of the blue mussel Mytilus galloprovincialis (Lam.). Temperature and copper exerted additive effects on lysosomal membrane stability, exacerbating the toxic effects of metal cations present in non-physiological concentrations. Mussel lysosomal membrane stability is known to be positively related to scope for growth, indicating possible effects of increasing temperature on mussel populations in metal-polluted areas. To clarify the molecular response to environmental stressors, we used a cDNA microarray with 1,673 sequences to measure the relative transcript abundances in the gills of mussels exposed to copper (40 µg/L) and a temperature gradient (16°C, 20°C, and 24°C). In animals exposed only to heat stress, hierarchical clustering of the microarray data revealed three main clusters, which were largely dominated by down-regulation of translation-related differentially expressed genes, drastic up-regulation of protein folding related genes, and genes involved in chitin metabolism. The response of mussels exposed to copper at 24°C was characterized by an opposite pattern of the genes involved in translation, most of which were up-regulated, as well as the down-regulation of genes encoding heat shock proteins and “microtubule-based movement” proteins. Our data provide novel information on the transcriptomic modulations in mussels facing temperature increases and high copper concentrations; these data highlight the risk of marine life exposed to toxic chemicals in the presence of temperature increases due to climate change.

Molecular cloning of metal-responsive transcription factor-1 (MTF-1) and transcriptional responses to metal and heat stresses in Pacific abalone, Haliotis discus hannai

“…Accordant with this explanation, the potential involvement of MT protein in the heat shock response has already been reported in this abalone species and also in other aquatic animals (Lee and Nam 2016a;Negri et al 2013;Jarque et al 2014). Within this context, the cold shock-induced MTF-1 has been reported in the common carp (Cyprinus carpio) brain, with an explanation that sudden temperature drop gave rise to the alteration of physiologically accessible Zn concentrations in that tissue (Ferencz and Hermesz 2008).…”

The effects of zinc nanooxide on cellular stress responses of the freshwater mussels Unio tumidus are modulated by elevated temperature and organic pollutants

“…Temperature stress has been associated with elevated ROS production and oxidative damage in other bivalves (Abele et al, 2002;Heise et al, 2003;Verlecar et al, 2007) including U. tumidus (Falfushynska et al, 2014b,a). Elevated ambient temperatures can also increase sensitivity of bivalves to the pollutants' toxicity by enhancing the oxidative injury (Lannig et al, 2006;Sokolova and Lannig, 2008;Katsikatsou et al, 2011;Ivanina et al, 2012), causing elevated levels of DNA strand breaks (Gagné et al, 2007), and exacerbating the negative effects of pollutants on lysosomal membrane stability and gene transcription (Negri et al, 2013;Izagirre et al, 2014).…”

Transcriptomic, Biochemical, and Histopathological Responses of the Clam Ruditapes decussatus from a Metal-Contaminated Tunis Lagoon

“…Many studies have demonstrated that several bivalve species have a great ability to accumulate organic pollutants and heavy metals and, thus, can be used as sensitive in situ indicators for pollution assessment (Wetzel and Van Vleet 2004;Oros and Ross 2005;Zhu et al 2005). Molecular approaches have been investigated by many authors to monitor the contamination impact on aquatic organisms and to better understand the early cellular events associated with the sensing and protective responses that occur upon exposure to contaminants (Negri et al 2013;Arini et al 2014;Banni et al 2014;Dedeh et al 2015).…”