PARENT SESSION
PMA08 - Adaption/Acquired Environmental Resistance
8:00 AM to 6:30 PM - Monday, November 12, 2001
Exhibit Hall A

(PM151) The Occurrence of NADPH-ferrihemoprotein Reductase in the Digestive Epithelia of Corbula caribea, from a Natural Oil Seep.

Mohammed, Azad^1,2, Agard, John¹, ^{1 2}

ABSTRACT- Chronic exposure to petroleum hydrocarbons, pose a pervasive treat to the survival of organisms. However, many animals possess innate homeostatic mechanisms, which reduce the toxic effects of these compounds. Corbula caribea is the most common non-polychaete macrofaunal organism identified at a large natural oil seep at La Brea in south Trinidad. It is hypothesized that these animals may possess components of the Mixed Function Oxygenase system (MFO), which may allow then to ameliorate the potentially deleterious effects that may result from exposure to the high levels of petroleum hydrocarbons within this environment. Though MFO activity has not been detected in bivalves, some studies have shown induction of components of the system (NADPH-ferrihemoprotein reductase). NADPH-ferrihemoprotein reductase activity was determined by incubating 10m cryostat sections with a ditetrazolium salt. The reaction produces a coloured diformazan deposit, which can be detected by visual assessment and quantified by measuring the relative stain intensity. The relative stain intensity of NADPH-ferrihemoprotein reductase determined for organisms from the seep was 61.30. This was significantly higher than the stain intensity determined for organisms from the two non-seep reference sites (15.63 and 7.11). This supported visual assessments, which indicated more intense staining in the seep organisms. Hence, indicating that organisms from the seep had higher levels of NADPH-ferrihemoprotein reductase than organisms from the non-seep sites. The presence of this component of the MFO system may enable these animals to tolerate chronic exposure to petroleum hydrocarbons and offer then a selective advantage for survival within this environment.

Key words: NADPH-ferrihemoprotein reductase, Natural oil seep, Corbula caribea, mixed function oxidases