Slime and fibers protect: hagfish

1 of 1

Glands of hagfish protect it from predators by secreting a complex material of fibers and rapid water-absorbing slime.

Biomimicry Taxonomy

	Maintain physical integrity >
	Protect from biotic factors >
	Animals

Biomimetic Application Ideas

Quick set insulation, that dehydrates to form a bubble layer Quick stop of flowing blood or fluids for coagulation Lubrication

> Visit strategy page

[Collapse all sections] Summary

"When the hagfish is provoked, slime oozes from the hundred or so glands that line its body. The secretion swells in contact with sea water until it forms a slimy cocoon around the fish. The glands also secrete fine fibers that reinforce the slime and allow it to stretch without breaking. Each thread is more than 2 inches (50 cm) long, but the hagfish employs a neat method to prevent tangling - the threads are played out from the glands in winding layers, like a nautical rope stacked into a figure eight." (Downer 2002:104-105)

Excerpt

"Hagfishes are known for producing large volumes of slime when stressed. Their slime is believed to act as a defence mechanism against gill-breathing predators, as it has been shown to reduce water flow over the gills of fish. Hagfish slime is composed of two interacting components, slime thread skeins and mucin vesicles, which are both released from glands along the ventrolateral length of the animal. Each slime gland is surrounded by striated muscle and a connective tissue capsule, and contains large numbers of gland thread cells and gland mucous cells. Gland thread cells contain skeins of tightly coiled polymers rich in intermediate filaments, while gland mucous cells produce vesicles containing mucins, a class of glycoproteins. Both cell types rupture partially as they pass through the slime gland duct, causing each to lose its plasma membrane, and releasing both thread skeins and mucin vesicles into the external environment. The mucin vesicles are released by holocrine secretion rather than the more typical mechanism of mucus secretion through fusion of vesicles with the membrane of the mucous cell and release of mucin granules by exocytosis. In this way, the mucin vesicles remain intact until they come into contact with seawater in the external environment.

"The mature slime is formed when exudate released from the hagfish contacts convectively mixing seawater. Agitation during mixing causes the thread skeins to uncoil to lengths of 10–17 cm, providing a large surface area to which the mucins released from the ruptured vesicles can attach. The fully formed slime is a complex network capable of confining seawater to channels between the slime threads and ruptured mucins like a fine sieve. The interaction between the thread skeins and ruptured mucins is critical for the production of the mature slime." (Herr et al. 2010:1092; citations removed from quote)

"When agitated, Atlantic hagfish (Myxine glutinosa) produce large quantities of slime that consists of hydrated bundles of protein filaments and membrane-bound mucin vesicles from numerous slime glands. When the slime exudate contacts seawater, the thread bundles unravel and the mucin vesicles swell and rupture. Little is known about the mechanisms of vesicle rupture in seawater and stabilization within the gland, although it is believed that the vesicle membrane is permeable to most ions except polyvalent anions. We hypothesized that the most abundant compounds within the slime gland exudate have a stabilizing effect on the mucin vesicles. To test this hypothesis, we measured the chemical composition of the fluid component of hagfish slime exudate and conducted functional assays with these solutes to test their ability to keep the vesicles in a condensed state. We found K+ concentrations that were elevated relative to plasma, and Na+, Cl– and Ca2+ concentrations that were considerably lower. Our analysis also revealed high levels of methylamines such as trimethylamine oxide (TMAO), betaine and dimethylglycine, which had a combined concentration of 388 mmol l–1 in the glandular fluid. In vitro rupture assays demonstrated that both TMAO and betaine had a significant effect on rupture, but neither was capable of completely abolishing mucin swelling and rupture, even at high concentrations. This suggests that some other mechanism such as the chemical microenvironment within gland mucous cells, or hydrostatic pressure is responsible for stabilization of the vesicles within the gland." (Herr et al. 2010:1092)

"Hagfishes are benthic marine protovertebrates that secrete copiousquantities of slime when threatened. The slime originates asa two-component glandular exudate comprised of coiled bundlesof cytoskeletal intermediate filaments (thread skeins) and mucinvesicles. Holocrine secretion of the slime into seawater resultsin the rapid deployment of both fibrous and mucin components,resulting in about a liter of dilute slime. Deployment of thethread skeins involves their unraveling in a fraction of a secondfrom a 150 µm-long ellipsoid bundle to a thread that is100x longer. We hypothesized that thread skein deployment requiresboth vigorous hydrodynamic mixing and the presence of mucinvesicles, both of which are required for whole slime deployment.Here we provide evidence that mixing and mucin vesicles areindeed crucial for skein unraveling. Specifically, we show thatmucin vesicles mixed into seawater swell and elongate into high-aspectratio mucin strands that attach to the thread skeins, transmithydrodynamic forces to them and effect their unraveling by loadingthem in tension. Our discovery of mucin strands in hagfish slimenot only provides a mechanism for the rapid deployment of threadskeins in vivo, it also helps explain how hagfish slime is ableto trap such impressive volumes of seawater via viscous entrainment.We believe that the deployment of thread skeins via their interactionwith shear-elongated mucins represents a unique mechanism inbiology and may lead to novel technologies for transmittinghydrodynamic forces to microscale particles that would typicallybe immune to such forces." (Winegard & Fudge 2010:1235)

About the inspiring organism

Atlantic hagfish
Myxine glutinosa Linnaeus, 1758
[Borer, Common hag, Hagfish, Hag-fish, Northern hagfish]

IUCN Red List Status: Not Evaluated

Some organism data provided by: FishBase
Organism/taxonomy data provided by:
Species 2000 & ITIS Catalogue of Life: 2008 Annual Checklist

Bioinspired products and application ideas

Application Ideas: Quick set insulation, that dehydrates to form a bubble layer. Quick stop of flowing blood or fluids for coagulation. Package theft deterrent system, or damage indication- micro water capsules break forming the slime. Lubrication.

Industrial Sector(s) interested in this strategy: Building, construction, medical, textile

Experts

Comparative Biomaterials Lab
Douglas S. Fudge
Department of Integrative Biology, University of Guelph

References

Downer, J. 2002. Weird Nature: An Astonishing Exploration of Nature's Strangest Behavior. Ontario: Firefly Books.

Herr JE; Weingard TM; O'Donnell MJ; Yancey PH; Judge DS. 2010. Stabilization and swelling of hagfish slime mucin vesicles. Journal of Experimental Biology. 213(7): 1092-1099.

Winegard TM; Fudge DS. 2010. Deployment of hagfish slime thread skeins requires the transmission of mixing forces via mucin strands. Journal of Experimental Biology. 213(8): 1235-1240.

Slime and fibers protect: hagfish

Content tools

Curator of this page

Comments