Nixon, M. and J. Messenger. (Eds). (1977) The biology of Cephalopods. London: Academic Press.

Hanlon, R.T. (Ed) (1988). AMU International Symposium on Life History, Systematics and Zoogeography of Cephalopods. Malacologia Vol. 29(1).

Boucaud-Camou, E. (1991) The Cuttlefish, First Intenational Symposium on the Cuttlefish Sepia. Centre de Publications de l'Université de Caen, Caen 358 pp.

Jereb, P., S. Ragonese and S. v. Boletzky. (1991) Squid age determination using statoliths. Proceedings of the International Workshop, 9-14 Oct. 1989, Mazara del Vallo, Italy. N.T.R.-I.T.P.P. Special Publication 1.

Roper, C.F.E., M.J.Sweeney and M. Vecchione. (Eds) (1991). Gilbert Voss International Symposium. Bull. Mar. Sci. Vol. 49(1&2). 

Okutani, T., R.K. O'dor, T. Kubodera. (Eds) (1993). Recent Advances in Cephalopod Fisheries Biology. Tokyo: Tokai University Press. 

Payne, A.I.L., M.R. Lipinski, M.R. Clarke and M.A.C. Roeleveld. (Eds) (1998). Cephalopod biodiversity, ecology and evolution. South African Jour. of Marine Science. Vol. 20.

Cephalopod Physiology and Anatomy

Budelmann, B.U. (1994) Cephalopod sense organs, nerves and the brain: adaptations for high performance and life style. Mar. Fresh . Behav. Physiol. 25:21-33.

Budelmann, B.U., R. Schipp and S. von Boletzky (1996) Cephalopoda. In: Microscopic Anatomy of Invertebrates, Vol.6, F.W. Harrison and A.J. Kohn (eds.). Wiley and Liss, New York (300 pages, 400 figures, approx. 1200references.This monograph not only describes tissues and organs at gross anatomical, light microscopical and ultrastructural levels, but also includes references to their physiology)

Young, J.Z., 1971, The Anatomy of the Nervous System of Octopus vulgaris, Clarendon Press. Oxford.

Abbott, N.J., Williamson, R. and Maddock L. (1995) Cephalopod Neurobiology, Oxford University Press 

Poertner, H.O., O'Dor, R.K., and MacMillan, D.L. (Eds.) (1994) Physiology of Cephalopod Molluscs: Lifestyle and Performance Adaptations Gordon and Breach, Basel 1994 (Reprint of "Mar. Fresh. Behav. Physiol., Vol. 25.

Cephalopod Behavior

Boyle, P.R. (1986b) Neural control of cephalopod behavior. In A.O.D. Willows (ed): The         Mollusca, Vol. 9. Neurobiology and Behavior, Part 2. Orlando: Academic Press, pp. 1-99.

Hanlon, R.T., and J.B. Messenger (1996) Cephalopod Behaviour.  Cambridge University Press, Cambridge. (Now available in paperback at Amazon.com)

Moynihan, M., and A.F. Rodaniche (1982) The behavior and natural history of the    Caribbean reef squid Sepioteuthis sepioidea. Adv. Ethology 25:1-151.

Cephalopod Taxonomy/Systematics

Guerra, A. (1992) Mollusca, Cephalopoda. In M.A. Ramos et al. (eds): Fauna Iberica, Vol.1 Madrid: Museo Nacional de Ciencias Naturales, CSIC, pp. 1-327.

Nesis, K.N. (1987) Cephalopods of the World. Neptune City (New Jersey): T.F.H. Publications .

Sweeney, M.J., Roper, C.F.E., Mangold, K.M., Clarke, M.R., and Boletzky, S. von (Eds.) (1992)

Voss, N.A., Vecchione, M., Toll, R.B. and M.J. Sweeney (Eds.) (1998) Systematics and Biogeography of Cephalopods. Smithsonian Contributions to Zoology, Number 585

Cephalopod Pathology and Disease

Hanlon, R.T., and J.W. Forsythe (1990) Diseases of Mollusca: Cephalopoda. 1.1 Diseases Caused by Microorganisms. In O. Kinne (Ed.): Diseases of Marine Animals. Vol. 3. Hamburg: Biologische Anstalt Helgoland, pp. 23-46.

Hochberg, F.G. (1990) Diseases of Mollusca: Cephalopoda. 1.2 Diseases Caused by Protistans and Metazoans. In O. Kinne (Ed.): Diseases of Marine Animals. Vol. 3. Hamburg: Biologische Anstalt Helgoland, pp. 47-227.

Recent Biomedical Uses for Cephalopods, 1987-1994

If your browser is capable of viewing html charts, see uses.cfml to view the html version of this chart.

To view our Table of Recent Biomedical Uses for Squid, download uses.txt.

(If you have difficulty viewing this chart, please see Options for Viewing this Page.)

Citation List and Searchable Index:

Cit.txt: A text file of all the citations listed in the above chart, "Recent Biomedical Uses for Cephalopods." The NRCC is only able to provide reprints by request for articles and abstracts written by our faculty and staff.

The Peerless Squid

	A Brief View of the History of Squid Research
	The History of the NRCC
	The Squid
	Cephalopod Romance
	The Giant Axon and the Squid
	Using the Patch Clamp on Squid Cells

A Brief View of the History of Squid Research

In 1963, British scientists Alan Hodgkin and Andrew Huxley won the Nobel Prize for their description of the behavior of nerve impulses, which was based on squid models. The work of two other Nobel Laureates also depended on the squid: American George Wald, honored in 1967 for his research on chemical and physiological processes in the eye, and Bernard Katz of Great Britain, whose discoveries concerning the role played by chemicals in nerve impulses won him the prize in 1970.

What are the charms of this animal, which often ends up as a deep-fried appetizer?

Possessed of a giant nerve cell, the squid provides a window into how a nerve impulse is initiated and transmitted. This giant cell, or more specifically a large projection from the cell which is called an axon, is the best-known of the squid's virtues as a laboratory animal, but scientists use the creature's eyes, ink, and blood, for a wide range of studies at many institutions across the United States. In Asia, the countries of the Mediterranean, and other parts of the world, the squid is a popular protein-rich food source.

The giant nerve cell was first noted in scientific literature by L.W. Williams in 1909, though his observations slipped quickly into obscurity. In 1936, J. Z. Young, a London-based professor of anatomy who was unaware of Williams's work, rediscovered the curiosity. Inside the squid's mantle, its elongated propulsion center, Professor Young observed a "large" tubular structure-- which is to say the mysterious vessel was half a milimeter in diameter, or about the thickness of the lead in a mechanical pencil. In his early encounters with the structure, Young assumed it was a blood vessel. But with further dissections, he noticed its similarity to small nerve fibers surrounding it, as well as the fact that it never contained blood. Young theorized that the tubular structure must be a nerve fiber-- a giant axon.

Using a pair of electrodes, he stimulated surrounding nerve fibers and found that he could only produce large muscle contractions in the mantle when the large vessel remained intact. The suspect structure was indeed a single, huge axon! Here was a neurological model that had no peer in the animal kingdom.

Scientists quickly appreciated the significance of Young's finding, and squid research later became a major endeavor of laboratories in the United States and Great Britain.

The History of the NRCC

Dr. Roger Hanlon, former head of the DBMR (now the MRATP), describes the history of the NRCC:

"We started in 1975 because there were several scientists at UTMB who went to Woods Hole every summer, and they wanted to know if there were squid in the Gulf of Mexico that could be useful in their research," said Dr. Hanlon. He and his colleagues spent three years combing the Gulf and discovered that the local species of squid were largely unsuitable because they were either too small in size or they inhabited water too deep to catch in sufficient numbers.

Then the team decided to try growing squid from eggs. "The record on growing squid amounted to 100 years of complete failure," says Hanlon. But with excruciating attention to water quality and diet, the NRCC crew was able to raise a California species, Loligo opalescens, to maturity. "That was a great victory. But the problem was that the animal was a fairly small species, susceptible to disease, with a survival rate of less than 50 percent in our system. So we went after bigger species."

An attempt to raise a larger animal from the Azores Islands was thwarted by the fact that because it was a cold water species, a lengthy period of almost 18 months was required for it to reach maturity, a trait that made its culture prohibitively expensive.

Finally, in 1987 the team discovered Sepioteuthis lessoniana, a warm water squid that fattens to a hearty four and a half pounds in 135 days, with almost no mortality past the first week. The mariculture group (now known as the NRCC) now had the squid for which it had been searching.

The Squid

Squids, and their cousins, octopuses, hold a special place in the imaginary world of marine terror. Both are carnivores with grasping arms and tentacles and the ability to blast clouds of ink when threatened. But the squid, with its translucent body, eerie iridescence, and ghostly method of locomotion, is as beautiful as it is mysterious. The squid possesses eight short arms and two long tentacles, located near the head. All its appendages are equipped with adhesive discs, or suckers, used in feeding. The agile tentacles can shoot out and grab prey, usually fish and shrimp, with blazing speed.

A jet-propelled predator, the squid's feeding habits require fast responses and keen powers of observation. Through the contraction of the muscular wall of the mantle, the squid expels water out through a funnel-shaped tube that emerges below the head and can be aimed in any direction.

Cephalopod Romance

The male uses color cells on the surface of his skin, which are capable of turning a variety of hues in the red, brown, and yellow part of the color spectrum, to express his dominance over other males and to curry favor with females. While all that commotion might seem enough to cause sensory overload, this marine peacock also has thousands of special cells, called iridiophores, which reflect iridescent shades of blue, green, pink and gold.

Copulation is achieved by the male grasping his partner with a pair of arms and then scooping up a bundle of spermatophores, or sperm pods, from his mantle with a special arm equipped with a spoon-like depression for this purpose. In something akin to a hockey slapshot, he then puts the spermatophores into the female's mantle, cementing then in place with ejaculate. Within a few days, the female will lay her eggs, affixing them to an immobile object on the tank bottom. Having achieved her mission, the female dies shortly thereafter.

The Giant Axon and the Squid

When the giant axon is stimulated, muscles of the mantle contract simultaneously, with the impulse traveling the length of the mantle, sometimes as far as 12 inches, in less than one hundredth of a second. An amazing feat of neuro-transmission. This synchronous contraction of the muscles is necessary to efficient propulsion. If the contractions are haphazard, less water is forced out the siphon, reducing the squid's speed and mobility, causing him to either miss a meal or become one.

"A good analogy is the human heart," says John Forsythe. "All the muscle must contract at once for it to pump effectively. Otherwise you have fibrillation, and the heart fails."

Using the Patch Clamp on Squid Cells

The patch clamp, prosaic as it sounds, is a sophisticated procedure in which an extremely fine glass tube, the tip of which can be one hundred times smaller than a human hair in diameter, is placed on a membrane. Then suction is applied to draw a small part of tissue into the tube. "it's like a vice," says biophysicist Harvey M. Fishman, Ph.D. hfishman@utmb.edu, a professor in the Department of Physiology & Biophysics. "you hold the membrane and seal it electrically so that when you pass current through it, it's forced to go through that tiny patch of tissue." This permits the study of electrical conduction properties of large molecules within the patch. Physiologists are interested in these electrical impulses because they are fundamental to communication between cells-- essential to muscle contractions, nerve impulses, and life itself in multi-cell organisms.

Because a network of satellite cells surrounding the squid axon make patch clamp experiments difficult, the animal has been largely excluded from investigations requiring the popular technique.

However, a discovery in Fishman's lab earlier this year could prove to make it routine to use the patch clamp technique on squid. Fishman, aware of a similar phenomenon occurring in muscle tissue discovered recently by UTMB colleague, Philip G. Stein, Ph.D., decided to search for a naturally occurring expulsion of electrically excitable membrane from a severed axon fiber. When he and a research instructor Stein cut a freshly dissected axon in the lab and observed it under the microscope, they found that tiny vesicles formed from the surface membrane. They noted that these circular structures became enlarged through fusion and then migrated from the end of the cell.

The balls of membrane seem to represent a working model of the original axon, completely liberated from the satellite tissue that confounded patch clamp techniques. An ecstatic Fishman coined "axoballs" for the find.

"Axoballs may be a purer form of excitable membrane-- native membrane available without any biochemical processing," he says. "It could be an incredible tool for studying the movement of substances and electrical processes in nerve cells."

Other On-line Resources:

CephBase  A dynamic html relational database-driven interactive web page. The purpose of CephBase is to provide life history, distribution, catch and taxonomic data on all living species of cephalopods (octopus, squid, cuttlefish and nautilus).