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Snail secretion is a complex mixture of several components, including proteins, glycoproteins, mucopolysaccharides and smaller molecules. Its growing use in nutraceutical, cosmetic and biomedical applications, as well as a component of edible and green packaging to replace chemical plasticizer, implies more affordable and sustainable extraction methods. We chose four extracts obtained from Cornu aspersum snails, different by origin, extraction medium (namely, citric acid, lactic acid or none) and additives and we performed a series of characterizations including the SDS-page, the measure of pH and density, the evaluation of dry matter and of protein content, supported by structural determinations by means of UV-visible and infrared spectroscopy, X-Rays diffraction and thermogravimetric measurements. Biological assays comprising evaluation of cytotoxicity and antibacterial activity were also carried out. All the tests were performed both on the as received snail filtrates and on the samples after proper dialysis to remove preservatives added by manufacturers. The obtained results put into evidence that the properties and composition of the final extract are strongly influenced by the collection method, that can be relevant for the proper use of snail filtrate in specific applications., (© 2024. The Author(s).)

Over the past few years, biogenic methods for designing silver nanocomposites are in limelight due to their ability to generate semi-healthcare and para-pharmaceutical consumer goods. The present study reports the eco-friendly synthesis of silver nanoparticles from the hitherto unexplored mucus of territorial snail Achatina fulica by the facile, clean and easily scalable method. The detailed characterization of the resultant samples by UV-Visible Spectroscopy, FESEM-EDS, XRD and FTIR Spectroscopy techniques corroborated the formation of silver nanoparticles in snail mucus matrix. The resultant samples were tested against a broad range of Gram positive and Gram negative bacteria like Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and a fungal strain Aspergillus fumigatus by well diffusion method. The results indicate that silver nanoparticles in mucus matrix exhibit strong antibacterial as well as antifungal activity. The pertinent experiments were also performed to determine the inhibitory concentration against both bacterial and fungal strains. Anticancer activity was executed by in vitro method using cervical cancer cell lines. Curiously, our biogenically synthesized Ag nanoparticles in biocompatible mucus revealed anticancer activity and demonstrated more than 15% inhibition of Hela cells. We suggest an interesting possibility of formulating antimicrobial and possibly anticancer creams/gels for topical applications in skin ailments.

Gastric ulcer or peptic ulcer is a common disease worldwide. Basically, it develops when there is an imbalance between the protective and aggressive factors, especially at the luminal surface of epithelial cells. Thus, there is a constant interest in research new drugs for treatment of gastric ulcer. The snail secretion is a dense mucous, that covers the external surface of the snails, with important functions for the survival of snails. The biological proprieties of snail Helix Aspersa Muller mucus it has been known for centuries to treat human disorders in particular for skin disease. Recently the use of snail mucus has seen a worldwide increase, as a component in cosmetic product and it has been used in particular for the management of wound and skin disorders. In this study we use a murine model of ethanol intragastric administration which has been widely used to test the drugs efficacies and to explore the underlying mechanism for gastric ulcer development. The intragastric ethanol administration causes several mucosal damages and an induction of a severe inflammatory response. Our results show a significant protective effect of snail secretion filtrate in reducing macroscopic and histological lesions, as well the protective effect on mucus content, oxidative stress and inflammatory response. In conclusion this study demonstrate the protective effect of intragastrical snail secretion filtrate, in a model of ethanol-induced gastric ulcer in mice, suggesting its possible useful use in the treatment or prevention of gastric ulcer.

The number of newly discovered peptides from the transcriptomes and proteomes of animal venom arsenals is rapidly increasing, resulting in an abundance of uncharacterized peptides. There is a pressing need for a systematic, cost effective, and scalable approach to identify physiological effects of venom peptides. To address this discovery-to-function gap, we developed a sequence driven:activity-based hybrid approach for screening venom peptides that is amenable to large-venom peptide libraries with minimal amounts of peptide. Using this approach, we characterized the physiological and behavioral phenotypes of two peptides from the venom of predatory terebrid marine snails, teretoxins Tv1 from Terebra variegata and Tsu1.1 from Terebra subulata. Our results indicate that Tv1 and Tsu1.1 have distinct bioactivity. Tv1 (100 µM) had an antinociceptive effect in adult Drosophila using a thermal nociception assay to measure heat avoidance. Alternatively, Tsu1.1 (100 µM) increased food intake. These findings describe the first functional bioactivity of terebrid venom peptides in relation to pain and diet and indicate that Tv1 and Tsu1.1 may, respectively, act as antinociceptive and orexigenic agents. Tv1 and Tsu1.1 are distinct from previously identified venom peptides, expanding the toolkit of peptides that can potentially be used to investigate the physiological mechanisms of pain and diet.

Plants have evolved sophisticated embryo defences by kinetically-stable non-digestible storage proteins that lower the nutritional value of seeds, a strategy that have not been reported in animals. To further understand antinutritive defences in animals, we analysed PmPV1, massively accumulated in the eggs of the gastropod Pomacea maculata, focusing on how its structure and structural stability features affected its capacity to withstand passage through predator guts. The native protein withstands >50 min boiling and resists the denaturing detergent sodium dodecyl sulphate (SDS), indicating an unusually high structural stability (i.e., kinetic stability). PmPV1 is highly resistant to in vitro proteinase digestion and displays structural stability between pH 2.0-12.0 and 25-85 °C. Furthermore, PmPV1 withstands in vitro and mice digestion and is recovered unchanged in faeces, supporting an antinutritive defensive function. Subunit sequence similarities suggest a common origin and tolerance to mutations. This is the first known animal genus that, like plant seeds, lowers the nutritional value of eggs by kinetically-stable non-digestible storage proteins that survive the gut of predators unaffected. The selective pressure of the harsh gastrointestinal environment would have favoured their appearance, extending by convergent evolution the presence of plant-like hyperstable antinutritive proteins to unattended reproductive stages in animals.

Early research on the direction of coiling (chirality) in snails had a prominent role in the history of biology, and continues to mold current thinking about developmental evolution. Here, we investigated the pleiotropic effects of chirality alleles on shell shape and length, using a large set of data from the Polynesian land snail Partula suturalis. By examining the shells of individuals with different combinations of their own and their mother's chiral genotypes, we find that the effects of chiral genes on length and shape involve both the maternal genotype and the genotype of the individual itself. Thus, differences in shape are symptoms of developmental shifts caused by the chirality alleles, or by alleles at other loci in close linkage disequilibrium with them. Although changes in shell shape are not necessary concomitants of chiral evolution, the results illustrate the wider pleiotropic effects of the genes, or haplotypes, that influence chirality. As the data are a rare record of the association in nature between the phenotype and genotype of a locus showing maternal effects, the conclusions are likely to be relevant to the general understanding of the dynamics of maternal-effect genes, including how selection acts on them.

Natural composite materials are renowned for their mechanical strength and toughness: despite being highly mineralized, with the organic component constituting not more than a few per cent of the composite material, the fracture toughness exceeds that of single crystals of the pure mineral by two to three orders of magnitude. The judicious placement of the organic matrix, relative to the mineral phase, and the hierarchical structural architecture extending over several distinct length scales both play crucial roles in the mechanical response of natural composites to external loads. Here we use transmission electron microscopy studies and beam bending experiments to show that the resistance of the shell of the conch Strombus gigas to catastrophic fracture can be understood quantitatively by invoking two energy-dissipating mechanisms: multiple microcracking in the outer layers at low mechanical loads, and crack bridging in the shell's tougher middle layers at higher loads. Both mechanisms are intimately associated with the so-called crossed lamellar microarchitecture of the shell, which provides for 'channel' cracking in the outer layers and uncracked structural features that bridge crack surfaces, thereby significantly increasing the work of fracture, and hence the toughness, of the material. Despite a high mineral content of about 99% (by volume) of aragonite, the shell of Strombus gigas can thus be considered a 'ceramic plywood' and can guide the biomimetic design of tough, lightweight structures.