New insights into the possible multiple roles of histidine-rich glycoprotein in blue mussels

Exploring the immune resilience of Mediterranean mussels: Recent advances and future directions

The Mediterranean mussel (Mytilus galloprovincialis) is a key species in European aquaculture, known for its economic and societal importance, particularly as a primary source of income for local fisheries in European coastal areas. While historically resilient to the mass mortality events that have affected other bivalve species, M. galloprovincialis may face increasing threats from emerging pathogens, including bacteria, viruses, and eukaryotic parasites. These microorganisms, often opportunistic, pose heightened risks in the current climate change scenario, where heatwaves are becoming increasingly frequent and the persistent presence of pollutants is suspected to impair the functional response of hemocytes. Over the past decade, significant advancements in immunological research have provided deeper insights into the cellular and molecular mechanisms underlying the robust defense system of M. galloprovincialis, which allows this species to efficiently cope with a broad range of infections. By analyzing the scientific literature published on mussel immunology over the past ten years, this review consolidates current knowledge on the immune system of the Mediterranean mussel. We place a particular focus on the cellular and molecular components involved in the recognition and elimination of microbial pathogens and discuss how the most recent discoveries may inform improved management and disease mitigation strategies for Mediterranean mussel farming in the in the years to come.

Marine glycoproteins: a mine of their structures, functions and potential applications

Many bioactive compounds are reported from marine organisms, which are significantly different from those found in terrestrial organisms regarding their chemical structures and pharmacological activities. Marine glycoproteins (MGs) have aroused increasing attention as a good nutrient source owing to their potential applications in medicine, cosmetics and food. However, there is a lack of a comprehensive study on MGs to help readers understand the current state of research on marine-derived glycoproteins. The current review compiles the recent progress made on the structures and functions of MGs with future perspectives to maximize their value and applications via bibliometric analysis methods for the first time. The current research on MGs appears mostly limited to the laboratory, with no large-scale production of marine glycoproteins developed. The sugar chains are bound to proteins through covalent bonds that can readily be cleaved leading to difficultly in their separation and purification. Health effects attributed to MGs include treatment of inflammatory diseases, as well as anti-oxidant, immune modulation, anti-tumor, hypolipidemic, hypoglycemic, anti-bacterial and anti-freeze activities. This review can not only deepen the understanding of the functions of MGs, but also lay an important foundation for the further development and utilization of marine resources.

Bacterial community profiling of floating plastics from South Mediterranean sites: First evidence of effects on mussels as possible vehicles of transmission

Plastic wastes accumulation in marine environments is becoming a crucial issue; while the toxicity to biota is quite well explored, a gap of knowledge still exists on the role that plastics play in shaping bacterial community structures in marine conditions and their possible transmission to humans. The present study intended first to profile bacterial community structure in floating plastic particles (FP) biofilms and seawater from four Tunisian coastal areas using high-throughput sequencing (HTS) of 16S rDNA. Subsequently, mussels (Mytilus galloprovincialis) as filter feeding organisms were exposed to the FP to broaden the knowledge on the potential role played by environmental plastic particles in shaping bacterial community structures and on their possibility to act as vehicles of bacteria through the food web. The mussels' microbiota was microbiologically analyzed through HTS, and the Histidine Rich Glycoprotein (HRG) gene expression level was investigated as the main immune response. Our results clearly showed a great variation in the composition of bacterial communities of FP and seawater from different geographical areas. Moreover, the gills of mussels exposed to sterilized seawater and native FP from each site exhibited a wider bacterial biodiversity. The gene expression level of HRG was found to be significantly higher in animals exposed to native FP when compared to sterilized FP. Our results should be carefully considered in view of the Trojan horse effects of FP toward bacteria and its potential toxicity.