Cytogenetic analysis of the action of carcinogens and tumour inhibitors in Drosophila melanogaster VI. The Mutagenic cell Stage Response of the Male Germ Line to the ‘Nitrogen-Mustard’ Derivatives of Amino-acids, Carboxylic acids and amines

Abstract

A study was undertaken of the fluctuations in the sex-linked recessive lethal rate in the progeny of males treated with nitrogen mustards with different prosthetic groups. The mustard derivatives of amino-acids (particularly L-phenylalanine) were mutagenic on all stages of spermatogenesis including the spermatogonia; the activity being higher the younger the germ cell. The carboxylic acid mustards produce their effect on the post-meiotic sperm, especially the early spermatids, but are ineffective on spermatocytes and spermatogonia. The amine mustard corresponding to the phenylalanine derivative proved to be ineffective on the spermatogonia. The response of these cells, therefore, is a function of the amino-acid moeity of the mutagen, and is not merely due to the presence of an amino-group in the molecule. It is suggested that the amino-acid moeity favours mutagenicity in the gonia through "metabolic transport", whereby the reactive molecule is conveyed to sites of nucleoprotein synthesis during chromosome replication.