Mucomics is the study of mucus and its biochemical properties. This discipline has gained increasing attention due to the critical roles mucus plays in protection, adhesion, and communication across species. Ethical restrictions on vertebrate research have driven the interest in invertebrate models such as mollusks. Mollusks produce large amounts of mucus which has several functions, including immune defense, digestion, and environmental adaptation. Mollusks—terrestrial, freshwater, or marine—are valuable models for investigating mucus composition and its responses to environmental stressors, including heavy metal contamination. Histochemical and glycomic techniques have revealed variations in mucin glycosylation patterns that influence mucus functionality, such as its viscoelastic and adhesive properties. Bivalves and gastropods, widely used as bioindicators and generally not subject to regulatory constraints in experimental use, accumulate pollutants in their mucus, reflecting environmental health. Investigative techniques such as lectin histochemistry, proteomic, and glycomic analyses provide insights into the impact of contaminants on mucus composition. Further research on molluscan mucins can enhance understanding of their physiological roles, environmental interactions, and potential biomedical applications. By integrating molecular and histochemical approaches, mucomic studies offer a comprehensive perspective on mucus function, advancing both ecological monitoring and biotechnological applications.

An in situ analysis of mucin secretions along the annual cycle was performed on the striped Venus clam, Chamelea gallina. Individuals of both sexes from an exploited stock of Margherita di Savoia (Southern Adriatic Sea, Central Mediterranean Sea) were made in June 2020 and 2021, and in January 2021 and 2022, representative of summer and winter seasons, respectively. Tissues from the foot and the gills were analyzed for histochemical and lectin-histochemical analyses. Staining with Periodic Acid-Schiff, Alcian Blue pH 2.5 and High-Iron-Diamine indicated that mucins from both the foot and the gills were acidic, mostly sulfated. Lectin-binding analyses with PNA, SBA, WGA, LTA, UEA-I, AAA, SNA, MAA-II and ConA indicated the presence of N-acetyl-glycosaminylated, mannosylated and fucosylated residuals in the saccharidic chains. In the gills, the amount of acidic and glycosaminylated residuals was higher in summer in both sexes, whereas fucosylation was similar along the sampling period and mannosylation was never observed. In the foot, both surface epithelial and subepidermal secreting cells increased sulfation in winter in males, but not in females. Glycosaminylation and fucosylation were observed only in the surface cells of males. Mannosylated residuals were observed in all the foot cell types in both sexes. It is hypothesized that the observed qualitative and quantitative variations in mucin secretion is linked to the reproductive cycle.

Aluminum is the most abundant metal in the Earth's crust and is widely used in everyday life. In sea waters, the presence of dissolved Al is naturally limited to a few micrograms per litre, however anthropogenic activities tend to alter its concentration. Toxic effects caused by this metal have already been demonstrated on several taxa, as well as a direct correlation with various diseases, including neurodegenerative ones. Since bivalves proved good bioindicators for environmental and possibly human health, we tested by histochemical methods the effects of Aluminum on the muciparous tissues of the striped venus clam, Chamelea gallina. Aluminum chloride at concentrations of 25, 50, and 200 µM, respectively were administered to experimental groups of twenty clams housed under controlled conditions. Image analysis of tissues stained by conventional and lectin-histochemistry indicated both qualitative and quantitative alterations of the mucous secretion produced by the gills and feet epithelia of the clams. The acidity and viscosity of the mucus itself is altered, with possible repercussions on the health and survival of animals.

Background/Objectives: Unhealthy nutrition and lifestyles contribute to the development of chronic diseases such as cardiovascular disease, type 2 diabetes, and colorectal cancer. The Western diet can impair gastrointestinal motility and function. The underlying mechanisms that lead to changes in the mucus barrier and mucin profiles in response to these dietary patterns are still being studied. In mice, dietary fiber intake can improve the intestinal mucosal barrier function, enhance the differentiation process of goblet cells, and increase acidic mucin production. Our study aimed to investigate the effects of a high-fat diet (HFD) on colonic mucin expression and to assess whether chickpea accessions, known for their nutritional benefits, can mitigate these adverse effects. Methods: We investigated the effects of an HFD and an HFD associated with two accessions of chickpeas (HFD + MG_13; HFD + PI358934) on the mucin expression in murine colons of mice by conventional histochemistry and lectin-histochemistry, combined with chemical treatment and enzymatic digestion and immunohistochemistry. We evaluated possible alterations of Muc2, the main mucin secreted by the mucous cells of the colon. Results: HFD significantly reduced the expression of the mucin Muc2 and altered its composition in the colon. Compared to the CTRL group, distal and proximal measurements for HFD + PI, respectively, showed reductions of 78% and 36%; for the distal colon, a reduction of 34% was also observed for both the HFD and HFD + MG_13 diets. Changes in mucin glycosylation, including sialylation and sulfation, as well as residues such as N-acetylglucosamine, GalNAc, Mannose, and Galactose, were observed, suggesting a beneficial influence of chickpeas on mucosal integrity. In HFD + MG_13 these effects were reduced and resulted similar to the control. Conclusions: HFD reduces Muc2 expression in the colon and alters mucin composition: chickpea accessions, particularly MG_13, partially restore Muc2 levels and mucin oligosaccharide profiles, suggesting protective effects on the intestinal mucosal barrier.