A manual for ant chromosome preparations (an improved air-drying method) and Giemsa staining

Abstract

I. CHEMICALS (1) Colchicine stock solution (1mg/ml, 0.1% solution) (a) 50 mg colchicine (b) 50 ml distilled water (D.W.) * Store in a brown bottle and keep in a refrigerator. (2) Hypotonic solution (1% Sodium citrate solution) (a) 1 g Trisodium citrate dihydrate (b) 100 ml D.W. (3) Colchicine-hypotonic solution (* freshly prepared) 10 ml Hypotonic solution with 0.005 % colchicine (a) 0.5 ml Colchicine stock solution (b) 9.5 ml Hypotonic solution (4) Fixative I (* freshly prepared) 60% 1:1 Acetic-ethanol (a) Glacial acetic acid 3 ml (b) Ethanol (>99.5%) 3 ml (c) D.W. 4 ml * Don’t store Fixative I overnight, because it turns rapidly into ethyl acetate, which is deleterious to mitotic cells. * Don’t use old glacial acetic acid and ethanol that are near the bottom of a stock bottle or that have been left for several months. Both chemicals tend to absorb moisture from the air and chromosomes will be damaged by the contamination of water. (5) Fixative II (* freshly prepared) 4 ml Absolute 1:1 Acetic-ethanol (a) Glacial acetic acid 2 ml (b) Ethanol (>99.5%) 2 ml (6) Fixative III 2ml Glacial acetic acid (GAA) II. APPARATUS (Fig. 1) (1) A transmitted stereomicroscope (x20-x40) for dissecting out organs (Fig. 1a). (2) A pair of dissecting needles (Fig. 1b). (3) Four Pasteur pipettes each with a rubber nipple (Fig. 1c). (4) Centrifugation tube (Spits tube) (Fig. 1d). (5) Depression slides (hole slides) (Fig. 1e). (6) Slide glasses (Fig. 1f). * Store slides in 80% ethanol and dry with washed clean gauze as necessary. * If slides are oily, add a drop of fixative I on the slide, and clear with paper or washed clean gauze. (7) Test tube stand (Fig. 1g). (8) Filter paper (blotting paper) (Fig. 1h). (9) Rolled filter paper or paper towel (Fig. 1i). (10) Fingerstalls for the thumb and the forefinger (Fig. 1j). * To protect fingers from fixative. * Cut the tip of fingers of a vinyl glove for right hand. (11) Washed cotton gauze or tissue paper (Fig. 1k). (12) A glass engraving pen for label (Fig. 1l). (13) Forceps to open cocoons (Fig. 1m).