A preliminary investigation shows the nematode parasites of the earthworm to be excellent material for cytological and embryological research, in addition to being useful as material for class room study. Their neglected study has probably been due to lack of suitable culture methods. It has been found that the nematodes will live on a 2% agar plate upon which small bits of red beef are placed. For optimum prolificity, the temperature should be kept constant at 15° C. With the use of this method, the author has kept a rapid growing culture alive for the past six months. The ova of these nematodes have certain advantages over those of Ascaris, being less impervious. Several cleavages may occur during a two-hour class period. In addition, the Golgi material can be easily demonstrated and can be displaced by means of the ultracentrifuge. The eggs will cleave in the centrifuge at a force of 30,000 times gravity and the adult worms, embryos, and eggs will remain alive for at least 15 hours at that force. Upon centrifuging, the eggs are stratified into the following layers: (1) oil globules at the centripetal pole, (2) transparent cytoplasm, (3) granules at the centrifugal pole. Immediate examination of the eggs upon removal from the centrifuge often reveals many pseudopodia-like processes flowing out near the centripetal pole; and these, in many cases, are completely cut off. A study is being undertaken to determine whether or not chromosome diminution occurs in these parasites.
Proceedings of the Iowa Academy of Science
©1940 Iowa Academy of Science, Inc.
Sulkin, Norman M.
"A Preliminary Report on the use of Parasitic Nematodes of the Earthworm for Class Study and Cytological Research,"
Proceedings of the Iowa Academy of Science, 47(1), 415-417.
Available at: https://scholarworks.uni.edu/pias/vol47/iss1/102