Worm Breeder's Gazette 14(3): 24 (June 1, 1996)
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
University of Cologne, 50923 Cologne, Germany
Some time ago we reported on the generation of giant nematode worms after laser-induced fusion of oocytes (Irle & Schierenberg, WBG 12(4)). Recently I performed a new series of fusion experiments leading to an even higher yield of hatching giants. From 36 fusions of two adjacent oocytes 22 L1s hatched. Ten of them were allowed to develop into giant adults and to reproduce. The majority of these was fertile but produced less than 100 offspring. For observed defects, see our previous WBG report. To determine whether increased size results in higher than normal cell numbers, 3 morphogenesis stages of giant eggs were squashed, fixed and DAPI-stained according to the method of Gossett and Hecht (J. Histochem. Cytochem. 28, 507-510, 1980). The counted cell numbers equalled those in normal eggs. 3 L1s and 5 adults were fixed and DAPI-stained and their cell numbers were estimated. No significant difference to normal specimens was detected. Nuclei of the ventral cord were counted as 15 in the L1s and about 70 in adults. 18-20 gut cell nuclei were present in L1s and 33 or 34 in adults. These numbers are the same as in regular animals. In summary, our data indicate that the number of cells does not increase with body size and is apparently controlled independent of this parameter.