Internal Defense System of Mytilus galloprovincialis (Lamarck, 1819): Ecological Role of Hemocytes as Biomarkers for Thiacloprid and Benzo[a]Pyrene Pollution

Abstract

The introduction of pollutants, such as thiacloprid and benzo[a]pyrene (B[a]P), into the waters of urbanized coastal and estuarine areas through fossil fuel spills, domestic and industrial waste discharges, atmospheric inputs, and continental runoff poses a major threat to the fauna and flora of the aquatic environment and can have a significant impact on the internal defense system of invertebrates such as mussels. Using monoclonal and polyclonal anti-Toll-like receptor 2 (TLR2) and anti-inducible nitric oxide synthetase (iNOS) antibodies for the first time, this work aims to examine hemocytes in the mantle and gills of M. galloprovincialis as biomarkers of thiacloprid and B[a]P pollution and analyze their potential synergistic effect. To pursue this objective, samples were exposed to the pollutants, both individually and simultaneously. Subsequently, oxidative stress biomarkers were evaluated by enzymatic analysis, while tissue changes and the number of hemocytes in the different contaminated groups were assessed via histomorphological and immunohistochemical analyses. Our findings revealed that in comparison to a single exposure, the two pollutants together significantly elevated oxidative stress. Moreover, our data may potentially enhance knowledge on how TLR2 and iNOS work as part of the internal defense system of bivalves. This would help in creating new technologies and strategies, such as biosensors, that are more suitable for managing water pollution, and garnering new details on the condition of the marine ecosystem.

Exploring the Internal Defense System of Cerastoderma glaucum (Bruguière, 1789) Exposed to Pristine Microplastics: The Sentinel Role of Haemocytes as Biomarkers

“…Therefore, haemocytes of Mytilus galloprovincialis (Lamarck, 1819) are potential biomarkers for hydrocarbon and pesticide pollution. This was observed through a significant increase in these cells when exposed to benzo[a]pyrene and thiacloprid [45].…”

“…TLRs were identified in the earliest multicellular invertebrates, including sponges, cnidarians [80], and oligochaetes [81]. In our previous studies, it the presence of TLR2 was evaluated in several metazoans, including Polititapes aureus (Gmelin, 1791), M. galloprovincialis [45], the ascidian Styela plicata (Lesueur, 1823) [82], Eptatretus cirrhatus (J. R. Forster, 1801) [83], the cartilaginous fish Scyliorhinus canicular (Linnaeus, 1758) [84], and several bony fishes [84][85][86][87]. The innate immune molecules of invertebrates enable them to recognize, bind, and kill pathogens through a rich variety of processes [88].…”

“…It is well established that defense cells play a crucial role in aquatic animals as biomarkers for environmental monitoring. A growing body of evidence suggests that blood cells, in both invertebrates and vertebrates, can provide valuable insights into the effects of environmental stimuli [17,[45][46][47][48][49]. However, there is still a paucity of data regarding the defense responses of certain metazoans, such as C. glaucum, to specific contaminants.…”

Functional Adaptations of Hemocytes of Aplysia depilans (Gmelin, 1791) and Their Putative Role in Neuronal Regeneration

“…However, a similar number of membrane-bound receptors have been found in other deuterostomes and protostomes, including the Pacific oyster C. gigas [50]. In previous studies, we evaluated TLR2 presence in several metazoans: mollusks bivalves Polititapes aureus (Gmelin, 1791), Cerastoderma glaucum (Bruguière, 1789) [51], and Mytilus galloprovincialis (Lamarck, 1819) [52]; annelida Lumbricus terrestris (Linnaeus, 1758) [38]; protochordate tunicate Styela plicata (Lesuer, 1823) [53]; chordates cyclostomes Eptatretus cirrhatus (Forster, 1801) [54]; chondrichthyes Scyliorhinus canicula (Linnaeus, 1758) [55]; chordates osteichthyes Carassius auratus auratus (Linnaeus, 1758) [56], Polypterus senegalus (Cuvier, 1829), Lepisosteus oculatus (Winchell, 1864), Clarias batrachus (Linnaeus, 1758) [57], Periophthalmodon schlosseri (Pallas, 1770) [58], and Danio rerio (Hamilton, 1822) [59]; and in the marine mammal Stenella coeruleoalba (Meyen, 1833) [60]. TLR can be found in hemocytes more than in other tissues, and its transcription is significantly upregulated in bacterial and viral infections.…”

Contaminants of Emerging Concern: Antibiotics Research in Mussels from the Coasts of the Tyrrhenian Sea (Sardinia, Italy)

“…Furthermore, mussels are ecologically important and are a source of food for several other species, so anthropogenic pollutants can be conveyed into the food chain. Mussels are also used as animal models for aquatic toxicology studies of a wide number of contaminants, like heavy metals, pesticides, and microplastics [16][17][18].…”