Main Content

The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 2951

John J. Gilbert; Alpha-Tocopherol in Males of the Rotifer Asplanchna sieboldi: Its Metabolism and Its Distribution in the Testis and Rudimentary Gut. J.Exp.Zool. 181(1):117-128, 1972

Reprint

In File

Notes

New-born males produced by mictic females induced and cultured with emulsified dl-alpha-tocopherol-5-methyl-H3 were extracted with acetone. A thin-layer chromatogram of the extracted residue was divided into 20 1-cm fractions which were analyzed for radioactivity in a liquid scintillation spectrometer; 100% of the tritium-labeled lipid co-migrated with authentic alpha-tocopherol. Since known alpha-tocopherol metabolites have migration characteristics different from alpha-tocopherol in the chromatography system used, it was concluded that only undegraded alpha-tocopherol was present in the males. The efficiency of extraction of tritium label from 42 males was 89%, and 132 DPM were recovered from the thin-layer chromatogram. Therefore, each male contained about 5x10E-16 moles, 0.2 pg, or 10E7 molecules of alpha-tocopherol. The distribution of tritium-labeled alpha-tocopherol in embryonic and new-born males produced by mictic females induced and cultured with emulsified dl-alpha-tocopherol-5-methyl-H3 was analyzed by autoradiography. Background-corrected mean grain density values showed that, for two different new-born males, the amount of label in the testis was 3.7 and 6.7 times that in the rudimentary gut. Grains over the testis appeared to be randomly distributed while those over the rudimentary gut were primarily over the periphery. A semi-quantitative analysis of mictic females with male embryos in different stages of development showed that only in well differentiated males were grain densities over the testis noticeably greater than those over the rudimentary gut. In younger embryos grains appeared to be randomly distributed over the entire embryo. Grain densities over the rudimentary gut in males about to be born were much lower than those over embryos in earlier stages of development. These results, together with electron micrographs of the testis and rudimentary gut of new-born male Asplanchna and information available on the subcellular distribution of alpha-tocopherol in vertebrates and plants, suggest that during late development of the male embryo alpha-tocopherol-rich organelles such as mitochondria are lost from the degenerating tissue from which the rudimentary gut of the new-born male is derived. The results obtained are consistent with the hypothesis that alpha-tocopherol is essential for spermatogenesis or male fertility in A. sieboldi and that for this reason the species has evolved its requirement of alpha-tocopherol for mictic female production.