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Paul's Bizarre Worm Bazaar

Frequently Asked Questions

Last revised 14 October 1998 

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Q: What is the Bizarre Worm Bazaar?

A: An information resource for researchers using and/or looking for certain nematode cultures. It consists mainly of a list of the species that I have (had) in my culture collection. A datasheet is provided for each strain, with origins, classification, literature, etc. of that strain. Most strains are freely available for reasearch purposes, some are lost, and some are only conditionally available. This is not a sales catalog. I do not charge for sending cultures, but I do hope (and in some cases will verify) that requests are only for use of these nematodes in genuine research.

The Bazaar also has pictures of some of the listed strains, to illustrate some of the many different appearances of these and other nematode species. If you wish, you are free to download the files in question, but only for non-commercial purposes, and (if they are to be used in a publication) with the proper attribution to the original source.

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Q: What are worms?

A: Any invertebrate animal with elongate body and no obvious legs or wings. The word "worm" is a bucket term - it groups many different kinds of animals that are not necessarily related to one another, e.g. flatworms (Turbellaria), tapeworms (Cestoda), roundworms (Nematoda), earthworms (Oligochaeta), etc., etc. Thus, different kinds of worms really have very different biological properties, e.g. some flatworms and earthworms can regenerate large parts of their body, but no nematode is capable of such a feat.

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Q: What are nematodes?

A: Nematodes are an extremely diverse group of worms with a characteristic body plan that includes several remarkable anatomical and biochemical characters. They are pseudocoelomate, unsegmented protostomes with a mixture of   hexaradiatetriradiate and  bilateral body symmetry and with a life cycle passing through several moults. The body wall of nematodes consists of four sectors with muscles that are neither transverse nor exactly longitudinal, but rather longitudinally oblique. Unlike nearly all other multicellular animals (Metazoa), nematodes have muscle cells that reach out to nerves rather than vice versa. Nematodes also have some very unusual physiological capacities that are not known in other Metazoa. For instance: nematode messenger RNA (a type of molecule involved in the expression of genes) receives a transspliced leader sequence. Nematodes are capable of autonomous synthesis of poly-unsaturated fatty acids (i.e. the more healthy kind of fatty acids, which animals like us must obtain from food). The metabolic arsenal of nematode includes a glyoxylate cycle (an alternative mechanism for converting stored body fat into sugars).

Bilateral: Having one transverse axis of symmetry. The entire human body bilaterally symmetrical in most respects, but one hand or foot by itself is not.

Hexaradiate: Having six transverse axes of symmetry (e.g. like each cell in a beehive, or like the playing board for chinese checkers). All hexaradiate objects are necessarily also triradiate, whereas all triradiate objects are not necessarily hexaradiate.

Protostome: An animal in which the mouth has developed directly from the earliest embryonic "mouth" or blastopore. The alternative condition is called deuterostome, where the mouth develops secondarily from an opening that is not the blastopre, but lies at the other end of the embryonic gut from the blastopore.

Pseudocoelomate: An animal with a body cavity that is not a true coelom, i.e. it lacks an epithelial lining enveloping all organs and covering the internal surface of the body wall.

Triradiate: Having three transverse axes of symmetry (e.g. like the icon for radioactivity, or like a fully opened camera tripod)

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Q: How diverse are nematodes?

A: Nematodes may well be the most diverse group of multicellular animals. Unfortunately, most text books haven't got a clue, so repeat this sentence three times before you read on: PERHAPS THE MOST DIVERSE GROUP OF ANIMALS (x3).

No one knows even approximately how many species of nematodes currently exist on earth, but published figures range from less than 100,000 to 100 million - a difference of three orders of magnitude. The 100 Megaspecies estimate has given rise to the somewhat dubious statement that "four out of every five animals is a worm, and the fifth is a beetle". In reality, there is as yet no reliable way of estimating the total number of living insect species, and much less so the numbers of species of nematodes, fungi, mites, protozoans, bacteria, etc., etc. All we really know is that the estimated numbers for all these "creepy-crawlies" continue to increase drastically, as we assess more and more of their genetic diversity, rather than just their poorly visible morphology and anatomy. Most published figures for the number of living species of organisms may well be far below the mark, and nematodes are a significant chunk of the hidden part of this taxonomic iceberg.

"Nematodes diverse? Well maybe so, but they're still a uniform lot, aren't they?" Not on your life - this myth is largely based on the very few species that have been studied in greater detail. Most nematodes are worm-shaped, just like most insects have a body consisting of three main parts, or most tetrapod vertebrates have four limbs, but otherwise there are no bounds on their ecological, developmental, anatomical, biochemical and cytological diversity. Don't start me to talkin'...

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