Snail slime

{{Short description|External bodily secretion produced by snails}}

File:Cochlicella barbara 11-10-2011.jpg leaving a slime trail behind it.]]

Snail slime is a kind of mucus (an external bodily secretion) produced by snails, which are gastropod mollusks. Land snails and slugs both produce mucus, as does every other kind of gastropod, from marine, freshwater, and terrestrial habitats. The reproductive system of gastropods also produces mucus internally from special glands.

Chemically, the mucus produced by land-living gastropodes belongs to the class of glycosaminoglycans (previously called mucopolysaccharides). Externally, one kind of mucus is produced by the foot of the gastropod and is usually used for crawling. The other kind of external mucus has evolved to coat the external parts of the gastropod's body; in land species, this coating helps prevent desiccation of the exposed soft tissues. The foot mucus of a gastropod has some of the qualities of glue and some of the qualities of a lubricant, allowing land snails to crawl up vertical surfaces without falling off.{{cite web | title=Snail slime substitutes | publisher=Royal Society of Chemistry | date=2020-03-05 | url=https://www.rsc.org/news-events/articles/2007/03-march/slime-substitute/ | ref={{sfnref | Royal Society of Chemistry | 2020}} | access-date=2024-06-02}}

The slime trail that a land gastropod leaves behind is often visible as a silvery track on surfaces such as stone or concrete.

Description

File:Will-it-slip-or-will-i.jpg mucus between 71 proteins against ~180 related proteins that were found previously in other mollusks.{{Cite journal |last1=Cerullo |first1=Antonio R. |last2=McDermott |first2=Maxwell B. |last3=Pepi |first3=Lauren E. |last4=Liu |first4=Zhi-Lun |last5=Barry |first5=Diariou |last6=Zhang |first6=Sheng |last7=Yang |first7=Xu |last8=Chen |first8=Xi |last9=Azadi |first9=Parastoo |last10=Holford |first10=Mande |last11=Braunschweig |first11=Adam B. |date=2023-09-02 |title=Comparative mucomic analysis of three functionally distinct Cornu aspersum Secretions |journal=Nature Communications |language=en |volume=14 |issue=1 |pages=5361 |doi=10.1038/s41467-023-41094-z |pmid=37660066 |pmc=10475054 |issn=2041-1723|doi-access=free |bibcode=2023NatCo..14.5361C }}]]

Mucus is a gel consisting of a polymer network that functions as a protective layer for the integument and mucosal surfaces of both elementary animals and mammals.{{cite journal |last1=Verdugo |first1=P. |last2=Deyrup-Olsen |first2=I. |last3=Aitken |first3=M. |last4=Villalon |first4=M. |last5=Johnson |first5=D. |title=Molecular Mechanism of Mucin Secretion: I. The Role of Intragranular Charge Shielding |journal=Journal of Dental Research |date=February 1987 |volume=66 |issue=2 |pages=506–508 |doi=10.1177/00220345870660022001 |pmid=3476567}}

The mucus of gastropods is not only used as a coating to cover the surfaces on which the snail crawls and a coating to cover the exposed soft parts of the body but also sometimes to allow a resting snail to adhere passively to surfaces, such as rock. Gastropod mucus adhesion uses a temporary sealing structure called the epiphragm.Hickman, C., Roberts, L. and Larson, A. (2002). Principios integrales de Zoología.

11°. Ed. McGraw- Hill Interamericana. España. Pp 328, 329, 330, 333.

98 (Spanish translation) Mucus is produced by a large gland located below the snail's mouth.{{cite book |last1=Ruppert |first1=Edward E. |last2=Fox |first2=Richard S. |last3=Barnes |first3=Robert D. |title=Invertebrate zoology: a functional evolutionary approach |date=2004 |publisher=Thomson-Brooks/Cole |location=Belmont, CA |isbn=9780030259821 |edition=7th|oclc=752875516}}

The foot of gastropods is covered with a thin layer of this mucus, which is used for a variety of functions, including locomotion, adherence, lubrication, repulsing predators, recognizing other snails, following a trail to a known destination and during reproduction. The discharge looks like a gel and it contains approximately 91 to 98% water by weight, depending on the species, combined with a small amount of high molecular weight glycoproteins.{{cite journal |last1=Denny |first1=Mark W. |title=Mechanical Properties of Pedal Mucus and Their Consequences for Gastropod Structure and Performance |journal=American Zoologist |date=February 1984 |volume=24 |issue=1 |pages=23–36 |doi=10.1093/icb/24.1.23}} In Cornu aspersum, these glycoproteins reach weights of 82, 97 and 175 kDa.

File:Cornu aspersum (Segrijnslak).jpg]]

Locomotion

Locomotion in snails comes from a series of muscle contractions called pedal waves and relaxations called inter waves.{{Cite journal |last1=Lai |first1=Janice H. |last2=del Alamo |first2=Juan C. |last3=Rodríguez-Rodríguez |first3=Javier |last4=Lasheras |first4=Juan C. |date=2010-11-15 |title=The mechanics of the adhesive locomotion of terrestrial gastropods |url=https://doi.org/10.1242/jeb.046706 |journal=Journal of Experimental Biology |volume=213 |issue=22 |pages=3920–3933 |doi=10.1242/jeb.046706 |issn=1477-9145 |pmc=6514465 |pmid=21037072}} The waves created help propel the snail forward whilst pushing the thin layer of mucus used as lubrication, behind them. In an [https://journals.biologists.com/jeb Experimental Biology] article, research has been presented showing that each wave is indeed creating a propulsive force using the mucus to reduce resistance.

Land mollusks travel by adhesive locomotion via muscular waves that propagate from tail to head. The snail mucus has an adapted flow behavior that allows transmittance of the muscular force while maintaining adhesion.{{cite journal |last1=Ewoldt |first1=Randy H. |last2=Clasen |first2=Christian |last3=Hosoi |first3=A. E. |last4=McKinley |first4=Gareth H. |title=Rheological fingerprinting of gastropod pedal mucus and synthetic complex fluids for biomimicking adhesive locomotion |journal=Soft Matter |date=2007 |volume=3 |issue=5 |pages=634–643 |doi=10.1039/B615546D |pmid=32900028 |bibcode=2007SMat....3..634E |url=https://pubs.rsc.org/ko/content/articlelanding/2007/sm/b615546d|url-access=subscription }}{{cite journal |last1=Rühs |first1=Patrick A. |last2=Bergfreund |first2=Jotam |last3=Bertsch |first3=Pascal |last4=Gstöhl |first4=Stefan J. |last5=Fischer |first5=Peter |title=Complex fluids in animal survival strategies |journal=Soft Matter |date=2021 |volume=17 |issue=11 |pages=3022–3036 |doi=10.1039/D1SM00142F|pmid=33729256 |arxiv=2005.00773 |bibcode=2021SMat...17.3022R |doi-access=free }} When inactive, many mollusks of both marine and terrestrial species, use the secretion to stick to various surfaces. However, although it is so diluted that it can commonly act as a lubricant, it can also have strong adhesive properties.{{cite journal |last1=Pawlicki |first1=JM |last2=Pease |first2=LB |last3=Pierce |first3=CM |last4=Startz |first4=TP |last5=Zhang |first5=Y |last6=Smith |first6=AM |title=The effect of molluscan glue proteins on gel mechanics. |journal=The Journal of Experimental Biology |date=March 2004 |volume=207 |issue=Pt 7 |pages=1127–35 |doi=10.1242/jeb.00859 |pmid=14978055}} In their unique mating ritual, Limax maximus use a mucus thread to suspend themselves from elevated locations like tree branches. In Cornu aspersum, there are three types of secretion. One type is translucent and not adhesive, the kind that the snail leaves behind as it moves (the slime trail), another is similar but thicker, condensed, more viscous and elastic, which is used to adhere to various surfaces, and a third viscous coating on the dorsal surface that is a protective barrier. Both are clearly differentiated by the type of proteins present in them.Ibid.

Slime production

A snail releases different kinds of mucus depending on the way it is stimulated. When the stimulation is normal, the slime is viscous (sticky) but if the snail is disturbed continuously or even violently, it releases clear foamy secretions. If the snail is sexually aroused the slime it releases is clear and viscous. In the case of Cornu aspersum, the discharge is composed of synthesized products from various types of secretory glands. These are all single-cell glands found in connective tissue and they secrete their products via pores that pass between the epidermal cells. They are of various shapes and usually have a long excretory duct. There are eight different types of secreting glands. Four of these different types secrete protein, calcium, pigments and lipids.{{cite journal |last1=Campion |first1=Mary |title=The Structure and Function of the Cutaneous Glands in Helix aspersa |journal=Journal of Cell Science |date=1 June 1961 |volume=S3-102 |issue=58 |pages=195–216 |doi=10.1242/jcs.s3-102.58.195}}

Medical uses

Some of the characteristics of snail slime have shown to be useful in Chinese medicine.{{Citation needed|date=December 2024}} Traditional Chinese medicine has used slime in a variety of ways to treat a variety of illnesses and cosmetic issues. It has also been used as skin creams for wrinkles and dry skin in cosmetics.{{Cite web |title=4-in-1 Snail Mucin Serum |url=https://klove.beauty/ |access-date=2024-07-19 |website=Klove Beauty |language=en-US}}{{Cite journal |last1=Yu |first1=Dan-Ni |last2=Tian |first2=Dan |last3=He |first3=Ji-Huan |date=2018-06-01 |title=Snail-based nanofibers |url=https://www.sciencedirect.com/science/article/pii/S0167577X18302908 |journal=Materials Letters |language=en |volume=220 |pages=5–7 |doi=10.1016/j.matlet.2018.02.076 |bibcode=2018MatL..220....5Y |s2cid=139128984 |issn=0167-577X|url-access=subscription }} The Chinese also have used the color-fast dry qualities of snail slime as a natural dye that represented wealth and power. The mucus has demonstrated several biological activities including antimicrobial, antioxidant, anti-tyrosinase, and anti-tumoral activities.{{Cite journal |last1=Noothuan |first1=Nattaphop |last2=Apitanyasai |first2=Kantamas |last3=Panha |first3=Somsak |last4=Tassanakajon |first4=Anchalee |date=2021-04-15 |title=Snail mucus from the mantle and foot of two land snails, Lissachatina fulica and Hemiplecta distincta, exhibits different protein profile and biological activity |journal=BMC Research Notes |volume=14 |issue=1 |pages=138 |doi=10.1186/s13104-021-05557-0 |issn=1756-0500 |pmc=8050916 |pmid=33858499 |doi-access=free }}

A new generation of tissue adhesive has been developed by using natural adhesion phenomena and mechanisms, such as snail mucus gel, which exhibits excellent haemostatic activity, biocompatibility, and biodegradability. It is effective in accelerating the healing of full-thickness skin wounds in both normal and diabetic male rats.{{Cite journal |last1=Deng |first1=Tuo |last2=Gao |first2=Dongxiu |last3=Song |first3=Xuemei |last4=Zhou |first4=Zhipeng |last5=Zhou |first5=Lixiao |last6=Tao |first6=Maixian |last7=Jiang |first7=Zexiu |last8=Yang |first8=Lian |last9=Luo |first9=Lan |last10=Zhou |first10=Ankun |last11=Hu |first11=Lin |last12=Qin |first12=Hongbo |last13=Wu |first13=Mingyi |date=2023-01-24 |title=A natural biological adhesive from snail mucus for wound repair |journal=Nature Communications |language=en |volume=14 |issue=1 |pages=396 |doi=10.1038/s41467-023-35907-4 |pmid=36693849 |bibcode=2023NatCo..14..396D |s2cid=256230314 |issn=2041-1723|pmc=9873654 }}File:Helix pomatia on razor blade.jpg

File:Snail slime cosmetics for skin care.jpg

Snail slime

Description

Locomotion

Slime production

Medical uses

See also

References

Further reading