Worm Breeder's Gazette 2(1): 11
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.
Staining of small nematodes for cholinesterase activity gives very inconsistent results due to poor penetration of the reagents, notably the substrate. Although formaldehyde-fixation and cutting of the nematodes can help, staining is still too unreliable for substrate specificity-inhibitor studies. We have used mild ultrasonic treatment of the nematodes to improve staining consistency in wild-type C. elegans and four other species . C. elegans were sonicated for 20 seconds in distilled water (15 cubic cm) at 12 m (probe dia. 9mm) and then fixed in cold formalin for 2 hours. Worms severed just below the basal bulb were stained by the 'direct-coloring' thiocholine method . Under these conditions 80 of the nematodes showed intense staining in the region of the nerve ring which was identified as due to AChE (E.C.3.1.1.7) activity. Similar results were obtained with Panagrellus redivivus, Prionchulus punctatus, Aphelenchus avenae and Ditylenchus dipsaci, although the tylenchids required more rigorous ultrasonic treatments. The ultrasonic treatments used do not appear to change the structure of the pharyngeal region at the light microscope level (or at the EM level in P. redivivus). Further work is proceeding on the EM localization of AChE in the pharyngeal region of C. elegans.