Process of isolating chromosomes of White mice

By: Heydee A. Santos

Chromosome Preparation:

Chromosome of the bone marrow cells and testis were prepared afte one hour, the treatment into 0.025% colchicine (Fig. 6) at 0.25%ml per kilogram body weight. (Fig.10) the mice were sacrificed by cervical dislocation. The femur yields the bone marrow cells which were pumped out into the isotonic solution (2.2% sodium Citrate) through the sucking and pumping motion of the syringe with a fine needle.

Each Mouse was Weighed Prior to Colchicine Treated

The Mice were Pre-Treated with 0.25ml Colchicine one hour before

Chromosome Preparation:

The testis was pulled just above the penile organthrough an incision, again these was placed in anisotonic solution 2.2% (Sodium Citrate) forteasing to a fine suspension though a syringe. Thebone marrow cells and testis suspension weretransferred to a dryer tube. Spinning for five (5)minutes (Fig. 8), the supernatant was removed forcell breaking and stocking in a hypotonic solution(1.0% sodium citrate) for twelve (12) minutes.Fixation follows, for the testis cells suspension,three (3) fixation processed are needed. Flickingof the tube is also needed for the recovering ofmetaphase. Four (4) fixations are needed for thebone marrow cells suspension.

Slide Plating: Dried clean microscope slides (25x 75 mm)

previously soaked in a 1:1 ratio of Ethanol – Aceticacid solution, using a fine – tipped pasteur pipettes,a suspension was topped on a pre cleaned slide anddried by blowing the suspension under an infra – redlight. (Fig. 9). Slide was stained with temporarystain Toluidine – o, and covered with cover slips, andobserved with Zeiss standard 18 microscope cameraattachment using 25 – 40x objectives and a 10x / 18oculars with plerapo 100 / 1.3 oil immersionobjective, green filter and colpan 21 high copy film,it is an important Panchromatic fild packed byComlumbia

Suspension was Topped o a Pre-Cleaned Slide under an Infra – red Light.

Analysing chromosome

Normal chromosome of testis

Chromosomal Aberration on testis

Chromosomal Break at Control – Irridiated Mouse Bone Marrow Cells at Mitotic Metaphase

Sticky Chromosome

Reason of using white mice as a biological indicator

The mice were used as they are good biological indicator organism for the following reason:

(1) readily available (2) low cost (3) ease of handling (4) good chromosome condition and (5) have good correlation with other test organism.

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