Worm Breeder's Gazette 3(1): 12
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.
1. New Zeiss immersion oil (brown bottles) is toxic to C. elegans, whereas old oil (containing PCB, white bottles) is innocuous. New oil stops worms pumping immediately upon contact, while the PCB oil does not. L2s mounted on agar surrounded with new oil, fail to produce progeny. In the short term, this may not matter; indeed, the oil repels the worms and helps to stop them escaping. For long-term viability, 18 mm cover slips can be used so that the oil can be kept away from the agar: edges are sealed with Voltalef oil. J.E.K. mounts the worm on a 12 mm slab and fills in the edges with 2% agar. 2. Rapid demounting (a) Brief inspection. Trimming and sealing not necessary. (b) Stable mount. The worm is mounted under a 13 mm circular cover slip; the agar is not trimmed but covered with a square of Saran Wrap containing an 11 mm hole. Seal is good enough to prevent drying overnight. Very little immersion oil is applied to avoid wetting the plastic. Saran Wrap and cover slip can be removed quickly, leaving worm accessible on the agar (watch while lifting cover slip). Useful for:-laser microbeam operations, rapid fixation of transitory states. 3. Invertible mount - Horrible method: Developed for watching lateral cells through flips of later lethargi. 2% celloidin/amyl acetate spread on horizontal microscope slide (~0.1 ml/cm2); air dried under dust cover several days. 60 layer of 1% agarose cast on 22 x 40 mm cover slip (cellulose tape spacers); allowed to dry to ~40 ( edges just receeding); minute drop of buffer added with worm, covered with 10 mm square of the celloidin film, whose centre has been coated with bacteria as usual. Edges allowed to dry; flooded with immersion oil (new will do). Nomarski only slightly degraded through agarose; restraint of worm poor, dehydrates in a few hours. More details from J.E.S.