Inhibition of Schiff-Reagent Staining in Chromosomes of Ovigerous Tissues of Anoetids; Whole Mites and Sections

Abstract

Chromosomes of ovigerous tissue of anoetid species are difficult to stain with Feulgen reagents containing HCl and relatively high concentrations of SO₂. The crystals in somatic cells underlying the cuticle, reported to be guanine, can be removed from whole mites or sections when hydrolysed in 1 N HCl at 60 C for 4 min. The hydrolysate of about 1000 anoetid mites, Histiostoma feroniarum, which had been fixed in Carnoy's (6:3:1) fluid for 2 hr, brought to water and then hydrolyzed, inhibits the test-tube reaction between a Schiff reagent and formalin. Paper chromatography of the hydrolysate indicates that it consists of at least 4 components, one of which co-chromatograms with known guanine. The ultraviolet absorption of a mixture of hydrolysate and Schilf reagent indicates that a colorless complex is formed in such a mixture. The refractory response of ovigerous chromatin to Feulgen's reagent may result from the incomplete removal of crystals or hydrolytic products from mites, as well as from the continued hydrolysis by HCl, and from reduced sensitivity caused by excess SO₂, in some preparations of the staining solution.