Effects of growth inhibitors on development of the reproductive system of the free-living nematode Panagrellus redivivus (Cephalobidae)

Abstract

The effects of inhibitors of ribonucleic acid (RNA), protein, and deoxyribonucleic acid (DNA) synthesis on growth and gonad development during synchronized post embryonic development of the free-living nematode Panagrellus redivivus was examined. Actinomycin D (AMD) and actidione blocked growth and gonad development at each stage but to different degrees, while hydroxyurea had slight inhibitory effects on growth but stopped gonad differentiation. Fourth-stage larvae placed in AMD or actidione failed to undergo gonad differentiation. Hydroxyurea blocked the morphological organization of the gonad but had little if any effect on growth; a high level of cell proliferation is evident while gonad differentiation is never achieved. Renewal of DNA synthesis in the fourth molt is required to complete development. The uncoupling of growth and gonad development as a result of inhibition with AMD and actidione suggests that macromolecular information for division and proliferation of the gonad is laid down quite early, while the informational synthesis for differentiation occurs quite late.