Snail Mucins and Their Multifunctional Properties

Biological Strategy

Snails and slugs

C.K. Unsworth

Move in/on Solids

To obtain needed resources or escape predators, some living systems must move on solid substances, some must move within them, and others must do both. Solids vary in their form; they can be soft or porous like leaves, sand, skin, and snow, or hard like rock, ice, or tree bark. Movement can involve a whole living system, such as an ostrich running across the ground or an earthworm burrowing through the soil. It can also involve just part of a living system, such as a mosquito poking its mouthparts into skin. Solids vary in smoothness, stickiness, moisture content, density, etc, each of which presents different challenges. As a result, living systems have adaptations to meet one, and sometimes multiple, challenges. For example, some insects must be able to hold onto both rough and slippery leaf surfaces due to the diversity in their environment.

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Attach Temporarily

Living systems must sometimes, temporarily, stay in one place, climb or otherwise move around, or hold things together. This entails attaching temporarily with the ability to release, which minimizes energy and material use. Some living systems repeatedly attach, detach, and reattach for an extended time, such as over their lifetimes. Despite being temporary, these attachments must withstand physical and other forces until they have achieved their purpose. Therefore, living systems have adapted attachment mechanisms optimized for the amount of time or number of times they must be used. An example is the gecko, which climbs walls by attaching its toes for less than a second. Other examples include insects that attach their eggs to a leaf until they hatch, and insects whose wings temporarily attach during flight but separate after landing.

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Gastropods

Class Gastropoda (“stomach-foot”): Snails and slugs

There are at least 40,000 known species of gastropod, with many more yet to be discovered, making it the largest class of mollusks. These animals exhibit torsion, meaning their internal organs are twisted 180° during development. The majority of gastropods have shells, and most open up on the right side. The largest gastropods are the size of a small child (3 feet, or 1 meter) while the smallest are barely visible to the naked eye.

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Rich in mucin proteins, snail mucus aids in locomotion, protection against microbes, and moisture retention.

Introduction

Snail mucus, a fascinating secretion produced by various snail species, serves multiple biological purposes, from protection against microbes to aiding movement and adhesion. Rich in specialized proteins called mucins, snail mucus plays a vital role in the survival and success of these animals across diverse environments. These mucins, highly glycosylated (sugar-rich) proteins, are critical for creating the unique characteristics of snail mucus, such as its ability to stick to surfaces, retain moisture, and resist microbial attack. The diversity and versatility of mucins make them a marvel of natural design, yet their molecular intricacies remain underexplored.

The Strategy

Snails produce mucin proteins as a key component of their mucus to meet their specific needs, whether for moving smoothly, staying attached to surfaces, or protecting themselves. Each mucin has a unique chemical composition that is ultimately responsible for its functionality. One key role of snail mucins is trapping water, giving mucus a slippery, gel-like consistency that helps snails slide along the ground without damaging their soft bodies. At the same time, the stickiness of mucus allows snails to climb walls, move upside down, or stay firmly in place.

The mucus secreted on a snail’s body also provides protection. It creates a barrier that shields the snail from bacteria and keeps its skin moist, even in dry conditions. Different snails have evolved specialized uses for mucus. For example, some snails use mucus to safeguard their eggs, while others, like the Costa Rican Land Snail, use it to cling to leaves and hide from the sun during droughts. The mucus on a snail’s foot is especially versatile, helping it grip surfaces while also reducing friction as it moves.

In addition to aiding movement and moisture retention, snail mucus fights off harmful microbes. Mucins in the mucus can stop bacteria from growing, protecting snails as they crawl over surfaces teeming with germs. For instance, mucus from the Giant African Land Snail has been shown to defend against common bacteria like Staphylococcus aureus and Escherichia coli. This natural antimicrobial property is vital since snails lack advanced immune systems and rely heavily on their mucus for protection.

The Potential

The adaptability of snail mucus could inspire biomimetic materials, such as surgical adhesives, sustainable hydrogels, and other specialty chemical solutions in skincare, biotech, and other markets. Studying the chemical makeup of mucin proteins in particular can offer immense potential for innovation, thanks to their unique antimicrobial, adhesive, and hydrating properties. In healthcare, the ability of mucins to combat antibiotic-resistant bacteria and promote wound healing makes them promising for advanced treatments like infection-resistant wound dressings.

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Last Updated January 30, 2025

References

Journal article

Advancing Discovery of Snail Mucins Function and Application

Front. Bioeng. Biotechnol. | October 2021 | Maxwell McDermott, Antonio R. Cerullo, James Parziale, Eleonora Achrak, Sharmin Sultana, Jennifer Ferd, Safiyah Samad, William Deng, Adam B. Braunschweig, Mandë Holford

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