The short-term incorporation of tritiated thymidine into the cytoplasm of cells undergoing oogenesis was investigated in Pteridium aquilinum using electron-microscope autoradiography. There was substantial uptake into the central cell and egg cell during the 6-h labelling period. The quantity and distribution of the label incorporated into the cytoplasm were closely similar in cells fixed immed...

Albino noninbred weanling male and female rats were fed a basic grain diet (Group 1) or a basic diet supplemented with 33% bracken fern [BF (Group 2)] or 0.1% quercetin [purity, > 99% (Group 3)] for 58 weeks. The quantities of quercetin and kaempferol (a close structural analog) in BF as glycosides were determined to be 0.57 and 1.1 g, respectively, per kg of dried BF. Estimated mean total cumu...

Bracken (Pteridium aquilinum) is a carcinogenic plant whose main toxin, ptaquiloside, causes cancer in farm and laboratory animals. Ptaquiloside contaminates underground waters as well as meat and milk from bracken-grazing animals and is a suspected human carcinogen. A better understanding of the underlying mechanisms of carcinogenesis can be achieved by studying the early stages of this proces...