抄録
A retinal substance was disclosed which was histochemically demonstrable by consecutive treatment with a concentrated solution of sodium bisulfite (15% aqueous solution,24 hours,20° C. ) and Schiff's reagent. Distribution of the substance in anuran rod acromeres (outer segments) corresponds to the site of positive tinctorial response in the peracetic acid Schiff staining, with the use of which comparative experimentation was made in order to obtain analytical data for the underlying mechanism of histochemical reaction of the substance.
The substance in question was learned to be favorably preserved by various aqueous fixatives containing either potassium bichromate or mercury chloride or both in combination or in sequence. Bisulfite Schiff reaction of the substance was effectively blocked by preceding bromination or iodination. So far as the pyridine-insoluble substance in the acromeres is concerned, the reaction was out of the blocking effect of acetylation. In test tube, it was observed that oleic acid gave positive bisulfite Schiff staining, while palmitic acid and stearic acid behaved negatively. Oleic acid after bromine treatment lost the responsibility to the staining. On the basis of such observations it is deduced that the present bisulfite Schiff staining of the retina might be due to possible interaction with ethylenic double bonds.
Pretreatment with semicarbazide, anilin chloride or phenylhydrazine blocked the staining, whereas hydroxylamine was without signifi- cant effect. Coloration resulting fromthe staining reaction is less re- sistant to acid. When bisulfite treatment preceded,, silver reaction became negative, but the affinity to thiazine dyes such as methylene blue and thionin was left unimpaired even under low pH condition. Thionin was responsible for metachromatic basophilia at pH 1.2. Such basophilia was lost by methylation (1 hour, ° C.; 6 hours, ° C. ), and the loss of basophilia was correlated with negative Schiff reaction. Both stainings were similarly affected by 2 days' iodination. Exposure of the substance to the air at 27° C. significantly interfered with subsequent Schiff reaction but did not affect the basophilia to any observable degree.
