Inhibition of cellular events during early algal gametophyte development: effects of select metals and an aqueous petroleum waste

Abstract

The effects of produced water (PW), an aqueous waste from oil production, and two metal constituents — arsenate (As) and copper (Cu), on development of gametophytes from a brown alga (the giant kelp, Macrocystis 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 replication and division of nuclear material to form two nuclei followed by translocation of one of the daughter nuclei. Nuclear migration was found to be highly susceptible to toxicants; exposure of gametophytes to concentrations of 80 μg/L As, 20 μg/L Cu, and 4% PW resulted in significant inhibition of nuclear migration. PW inhibition of nuclear migration 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 and/or inhibition of DNA replication are potential modes of action for the toxicants studied.