INHIBITION OF CELLULAR EVENTS DURING EARLY ALGAL GAMETOPHYTE DEVELOPMENT - EFFECTS OF SELECT METALS AND AN AQUEOUS PETROLEUM WASTE

The effects of produced water (PW), an aqueous waste from oil producti on, and two metal constituents - arsenate (As) and copper (Cu), on dev elopment of gametophytes from a brown alga (the giant kelp, Macrocysti s pyrifera) were investigated. Early gametophyte development involves zoospore germination, germ tube growth, and nuclear migration, all of which occur within 42 h of culture. Nuclear migration includes replica tion and division of nuclear material to form two nuclei followed by t ranslocation of one of the daughter nuclei. Nuclear migration was foun d to be highly susceptible to toxicants; exposure of gametophytes to c oncentrations of 80 mug/L As, 20 mug/L Cu, and 4% PW resulted in signi ficant inhibition of nuclear migration. PW inhibition of nuclear migra tion was found to be reversible, while inhibition by As was not; this suggests different cellular target sites or modes of action for these two toxicants. It has previously been shown that nuclear division and translocation are dependent on the integrity of specific cytoskeletal elements, microtubules. As such, inhibition of microtubule dynamics an d/or inhibition of DNA replication are potential modes of action for t he toxicants studied.