Improving Smear Technics by the Use of Enzymes

Abstract

A method for securing spreading of large meiotic chromosomes is described. It consists in treating a piece of fixed anther in a 1% solution of Clarase, a proprietary enzyme complex, or in an extract prepared by grinding the contents of flask cultures of certain fungi (Aspergillus niger, Chaetomium globosum, Metarrhizium sp.) with quartz sand in a mortar containing 10 ml. of a sodium acetate buffer, pH 5.0. The fixed anthers are thoroughly washed in H₂O prior to the enzyme treatment. Length of treatment may vary from as little as 10 minutes to several hours. The usual aceto-carmine or propionic-carmine smear technic may then be used. The treatment destroys some of the elasticity of the cytoplasm so that the chromosomes remain spread out when light pressure is exerted on the cover slip.