Author: Dr. Ellen Batchelder, Assistant Professor of Biology, Unity College, Unity, Maine
Figure 1: Panagrellus nematode carrying the same yeast they feed on.
Scientific and common name:
Nathan Cobb, the father of nematology in the US (Esser et al., 1989), is quoted in many sources for his reference to a species of nematode occurring in “… the felt mats on which Germans are accustomed to set their mugs of beer…” The nematode in question is known by the scientific binomial Panagrellus redivivus and more commonly as the beer mat nematode (Ferris, 2009) or the sour paste nematode (Stock and Nadler, 2006). In addition to German beer mats, it has also been isolated from rotten peaches and book binding paste (Ferris, 2009).
Taxonomy and Ecology:
What is now the genus Panagrellus was first called Chaos by Carl Linnaeus, the scientist who developed the system of binomial naming (Ferris, 2009), and he originally included protists and fungi along with nematodes in that genus. Today, Panagrellus includes at least 13 known species of nematodes that feed on fermenting yeast (Ferris, 2009), (Hechler, 1971). They are free-living nematodes found in habitats where certain species of yeast grow well, including beer mats, insect frass, tree wound slime, soiled cider (vinegar), thermal springs, and book binding glue (in fact, in other types of paste made from wheat flour) (Stock and Nadler, 2006), (Ferris, 2009).
Species of Panagrellus have been found so far in nearly all corners of the world except Antarctica and Australia (Stock and Nadler, 2006).
Physical description and life cycle:
Similar to many other nematodes, P. redivivus females are small (0.5 mm- 2 mm) with males
Figure 2: Panagrellus male tale with bifurcated spicule.
From: (Ferris, 2009) and (Hechler, 1971).
Panagrellus nematodes do not have many distinguishing anatomical characteristics, but a relatively wide, long mouth and several sets of teeth in adults are consistent with their diet of yeast (Ferris, 2009).
Pangrellus redivivus are known to aquarists as microworms (Atchison, 2009). They contain a relatively large amount of protein and lipids and are grown and sold as food for newly-hatched fish, crustaceans, newts, and frogs (Atchison, 2009), (Ferris, 2009). They can be grown in a liquid culture and fed on media containing oatmeal or other cooked cereals (Atchison, 2009). The grains provide food for yeast which, in turn, provide food for the reproducing nematodes.
Figure 3: head of P. redivivus, showing hourglass shaped esophagus. Scale bar 100 μm.
Forum: Photography through the microscope. Topic: Internal young - sour paste nematode (Panagrellus redivivus) Author: Visikol
- Atchison J. Microworms [Internet]. San Rafael(CA):The Bug Farm; [2009, cited 2014 Sept 5] . Available from: http://www.livefoodcultures.com/microworms_printversion.html
- Esser, R., Tarjan, A., and Perry, V. 1989. Jesse Roy Christie: The gentleman nematologist. Annu. Rev. Phytopathol. 27: 41-45.
- Ferris, H. 2009. The beer mat nematode, Panagrellus redivivus: A study of the connectedness of scientific discovery. J. Nematode Morphol. Syst., 12 (1): 19-25.
- Hechler, H. 1971. Taxonomic Notes on Four Species of Panagrellus Thorne (Nematoda: Cephalobidae) J. Nematol.3(3): 227–237.
- Stock, S., and Nadler, N. 2006. Morphological and molecular characterization of Panagrellus spp. (Cephalobina: Panagrolaimidae): taxonomic status and phylogenetic relationships. Nematology, Vol. 8(6), 921-938.
- Tree of Life Web Project. 2002. Animals. Metazoa. Version 01 January 2002 (temporary). http://tolweb.org/Animals/2474)/2002.01.01 in The Tree of Life Web Project, http://tolweb.org/