Citrulline-malate effect on microsome phospholipids and cytochrome P450 in Euglena grown with ethanol

Organic toxicants and plants

Organic xenobiotics absorbed by roots and leaves of higher plants are translocated by different physiological mechanisms. The following pathways of xenobiotic detoxication have been observed in higher plants: conjugation with such endogenous compounds as peptides, sugars, amino acids, and organic acids; oxidative degradation and consequent oxidation of xenobiotics with the final participation of their carbon atoms in regular cell metabolism. The small parts of xenobiotics are excreted maintaining their original structure and configuration. Enzymes catalyze oxidative degradation of xenobiotics from the initial hydroxylation to their deep oxidation. The wide intracellular distribution and inductive nature of oxidative enzymes lead to the high detoxication ability. With plant aging, transformation of the monooxygenase system into peroxidase takes place. Once in the cells, xenobiotics are incorporated into different cell organelles. All xenobiotics examined are characterized by a negative effect on cell ultrastructure. The penetration of high doses of xenobiotics into plant cells leads to significant deviations from the norm and, in some cases, even to the complete cell destruction and plant death.

Cytochrome P450 in parasitic protozoa and helminths

Cytochrome P450 has been demonstrated in flagellate and sporozoan Protozoa. In Plasmodium there is a correlation between chloroquine resistance and cytochrome P450 mono-oxygenase activity, but there is no evidence that the malarial parasite metabolises chloroquine by an oxidative mechanism. There is no evidence for cytochrome P450 in adult helminths (nematodes and platyhelminths) based on P450 content and mono-oxygenase activity with classical substrates, although low activities may be present in free-living larval stages.

Microsomal ethanol-oxidizing system in Euglena gracilis. Similarities between Euglena and mammalian cell systems

1. ADH activity of Euglena grown with 50 mM ethanol decreased, but MEOS activity increased with a corresponding increase in the total amount of cytochrome P-450. 2. Phenobarbital treatment increased the total amount of cytochrome P-450. 3. CO and KCN, cytochrome P-450 ligands, diminished acetaldehyde formed from ethanol oxidation by MEOS. 4. The amounts of NAD(P)H cytochrome c reductases and cytochrome b5 type, components of microsomal monooxygenase reaction, have been spectrophotometrically measured. 5. NAD(P)H cytochrome c reductases activities were induced by phenobarbital. 6. DMSO, an inhibitor of rabbit MEOS, inhibited O2 consumption (11-20%) by Euglena grown with an ethanol, but not a lactate medium. 7. These studies indicate the presence of cytochrome P-450-dependent MEOS in Euglena similar to that in the mammalian hepatic cell.