Combined effects of pentachlorophenol and salinity stress on chemiluminescence activity in two species of abalone

Abstract

The effect of pentachlorophenol (PCP) combined with salinity stress on hemocyte microbicidal activity was examined in two species of abalone. Microbicidal phagocytic function was determined in red ( Haliotis rufescens) and black ( Haliotis cracherodii) abalone after in vivo exposure to 25, 35 and 45‰ seawater salinity plus 1.2 mg/l PCP using luminol-dependent chemiluminescence (CL). Red and black abalone exposures of 3.5 and 6.5 h, respectively, were based on species-specific metabolic endpoints (MEPs) derived from previous nuclear magnetic resonance spectroscopy (NMR) data. Endpoints examined include total CL (CL total), peak CL (CL max), and the time to reach peak CL ( T max). Overall, black abalone CL was significantly greater than red abalone CL particularly at ambient and high salinities. High salinity alone had a dramatic effect on red abalone whereas black abalone demonstrated few salinity effects. While the addition of PCP stimulated CL max and CL total among red abalone at ambient and high salinities, PCP exposure inhibited CL max at each salinity and inhibited CL total at ambient salinity among black abalone. Black abalone generally did not demonstrate effects of PCP within the 3.5 h exposure period except at high salinity plus PCP, which caused a reduction of CL total. T max was greatly increased after PCP exposure at each salinity among red abalone but did not effect T max at any salinity tested among black abalone. No lysozyme activity was detected among red or black abalone after exposure to any of four different target particles tested either in the presence or absence of PCP. Overall, PCP in combination with salinity stress causes a modulation in the production of reactive oxygen species and this modulation varies between abalone species. Agents that decrease CL activity in hemocytes may reduce the antimicrobial potential of these cells thereby increasing susceptibility to infectious disease.