Evaluation of xenobiotic N- and S-oxidation by variant flavin-containing monooxygenase 1 (FMO1) enzymes.

The flavin-containing monooxygenase gene family (FMO1-6) in humans encodes five functional isoforms that catalyze the monooxygenation of numerous N-, P- and S-containing drugs and toxicants. A previous single nucleotide polymorphism (SNP) analysis of FMO1 in African-Americans identified seven novel SNPs. To determine the functional relevance of the coding FMO1 variants (H97Q, I303V, I303T, R502X), they were heterologously expressed using a baculovirus system.

Biochemical effects of petroleum exposure in hornyhead turbot (Pleuronichthys verticalis) exposed to a gradient of sediments collected from a natural petroleum seep in CA, USA.

Concentrations of serum/plasma estradiol, biliary fluorescent aromatic compounds (FACs), levels of hepatic CYP1A expression, and DNA damage were measured in sexually mature hornyhead turbot (Pleuronichthys verticalis) exposed in the laboratory for 7 days to a gradient of sediments collected from a natural petroleum seep in the Santa Barbara Channel. Coal oil point (COP) sediments were homogenized and divided into four treatments containing 0 (sediment from the Orange County Sanitation District's reference location), 33, 66, and 100% (COP) sediments. Sediment concentrations of 20 PAHs ranged from below the detection limit for the 0% COP sediment treatments to 105 microg/g in the 100% treatments with lower molecular weight compounds predominating.

Effects of salinity on the uptake, biotransformation, and toxicity of dietary seleno-L-methionine to rainbow trout.

Selenium (Se) is an element that has been of environmental concern in aquatic systems that drain arid regions heavily used for agricultural purposes. As hypersaline conditions are associated with these ecosystems, this study examined the effect of hypersaline water on the uptake, biotransformation, and toxicity of seleno-L-methionine (SeMe) in juvenile rainbow trout. Fish were acclimated for 5 days to four different salinity regimes (0.

Two new polymorphisms of the FMO3 gene in Caucasian and African-American populations: comparative genetic and functional studies.

To characterize the contribution of the human flavin-containing monooxygenase form 3 (FMO3) in the metabolism and disposition of drugs and xenobiotics, we determined the single nucleotide polymorphisms in the coding region and adjacent splice junctions of FMO3 in 134 African Americans and 120 Caucasians from the United States. In the regions examined, DNA resequencing or high throughput MassEXTEND studies coupled with mass spectrometric genotyping showed that 12 sites of variation were present. Three variants encoding synonymous mutations and four polymorphisms were observed in the noncoding region.

The relationships of biochemical endpoints to histopathology and population metrics in feral flatfish species collected near the municipal wastewater outfall of Orange County, California, USA.

In July 2000, 330 individuals of three flatfish species were collected from reference locations and nine sites surrounding the outfall of the Orange County (CA, USA) Sanitation District (OCSD) municipal wastewater discharge. Species included hornyhead turbot (Pleuronichthys verticalis), English sole (Pleuronectes vetulus), and bigmouth sole (Hippoglossina stomata). Livers of sampled animals were examined for the expression of vitellogenin (in males), cytochrome P450 1A (CYP1A), and DNA damage (comet assay).

Effects of the brominated phenol, lanosol, on cytochrome P-450 and glutathione transferase activities in Haliotis rufescens and Katharina tunicata.

The relationship between biochemical transformation mechanisms and dietary preferences has been little studied among marine herbivores. Here we report on basal activities and kinetic parameters of steroid hydroxylase and glutathione transferase from digestive gland tissue of the marine molluscan generalist herbivores Haliotis rufescens and Katharina tunicata and the differential effects of the brominated phenol lanosol [1,2-dihydroxy-3,4-dibromo-5-(hydroxymethyl)-benzene] on the activity of these enzymes. Lanosol and other brominated aromatic compounds are prevalent among filamentous red algae frequently consumed by K.

Biochemical and clinical aspects of the human flavin-containing monooxygenase form 3 (FMO3) related to trimethylaminuria.

Trimethylaminuria is a rare metabolic disorder that is associated with abnormal amounts of the dietary-derived trimethylamine. Excess unmetabolized trimethylamine in the urine, sweat and other body secretions confers a strong, foul body odor that can affect the individual's ability to work or engage in social activities. This review summarizes the biochemical aspects of the condition and the classification of the disorder into: 1) primary genetic form, 2) acquired form, 3) childhood forms, 4) transient form associated with menstruation, 5) precursor overload and 6) disease states.

Comparison of in vitro and in vivo bioassays for estrogenicity in effluent from North American municipal wastewater facilities.

Attempts to better understand causal factors affecting estrogenicity in municipal wastewater have primarily focused on analytical evaluation of specific chemical estrogens and the use of estrogen receptor (ER) based in vitro assays. To compare analytical,in vitro, and in vivo assays for estrogenicity, wastewater from four New York and one Texas municipal wastewater facilities was evaluated for estrogenic activity using the yeast estrogen screen assay (YES) and an in vivo fish vitellogenin (VTG) assay. Estrogenic activity, as measured by the YES assay, was observed in methanol and/or methylene chloride eluents from C18 extracts in two of the New York treatment facilities and the Texas facility.

Identification of novel variants of the flavin-containing monooxygenase gene family in African Americans.

Sequence polymorphisms in enzymes involved in drug metabolism have been widely implicated in the differences observed in the sensitivity to various xenobiotics. The flavin-containing monooxygenase (FMO) gene family in humans catalyzes the monooxygenation of numerous N-, P- and S-containing drugs, pesticides, and environmental toxicants. Six genes (FMO1-6) have been identified so far, but the major alleles of FMO2 and FMO6 encode nonfunctional proteins due to a nonsense mutation and splice-site abnormalities, respectively.

Determination of beta-adrenergic receptor blocking pharmaceuticals in United States wastewater effluent.

Beta adrenergic receptor antagonists (beta-Blockers) are frequently prescribed medications in the United States and have been identified in European municipal wastewater effluent, however no studies to date have investigated these compounds in United States wastewater effluent. Municipal wastewater effluent was collected from treatment facilities in Mississippi, Texas, and New York to investigate the occurrence of metoprolol, nadolol, and propranolol. Propranolol was identified in all wastewater samples analyzed (n = 34) at concentrations < or = 1.

Estrogenic responses of larval sunshine bass (Morone saxatilis x M. Chrysops) exposed to New York City sewage effluent.

To determine the estrogenicity of effluents from sewage treatment plants (STPs) to larval fish, 2-day-old sunshine bass were exposed to effluents from three STPs serving New York City (NYC), varying in size and treatment level. Estrogenic response was evaluated by measuring vitellogenin (VTG) and estrogen receptor (ER) expression in cytosolic fractions of whole body homogenates. Concentrations of the presumptive endocrine disruptors in the effluents were also measured.

Cloning and sequencing of cytochrome P450 2X1 from channel catfish (Ictalurus punctatus).

Previous purification and immunochemical studies in livers of channel catfish indicated the presence of at least four cytochrome P450 (CYP) 2-like isoforms. Sequencing of the first 18 amino acids of one purified form indicated a CYP2 isoform. From this N-terminal sequence and other published CYP2 sequences from fish, primers were designed and a full-length CYP cDNA was identified from reverse-transcribed catfish liver mRNA.

Effect of cortisol and urea on flavin monooxygenase activity and expression in rainbow trout, Oncorhynchus mykiss.

Expression of flavin-containing monooxygenase(s) (FMO) correlates with salinity exposure in certain species of euryhaline fish, such as the rainbow trout, Oncorhynchus mykiss. The mechanism(s) by which salinity regulates FMO is unclear. Adult rainbow trout were infused through the dorsal aorta with either cortisol or urea.

Predicting chemical contaminants in freshwater sediments through the use of historical biochemical endpoints in resident fish species.

Previous studies in Bayou Bartholomew, Arkansas, USA, indicated significant relationships between the individual health of fish sampled from 13 sites and specific biochemical responses. Evaluation of several biochemical endpoints in 1994 indicated the bioavailable occurrence of either polychlorinated biphenyl (PCB) congeners or metals. To evaluate this possibility, in December 2000, sediments were collected at four sites on Bayou Bartholomew, where fish, collected in July 1994, had previously demonstrated the highest hepatic cytochrome P4501A (CYP1A) and heme oxygenase (HO) expression.

Gender differences in the effect of salinity on aldicarb uptake, elimination, and in vitro metabolism in Japanese medaka, Oryzias latipes.

Toxicity studies have shown that salinity enhances the toxicity of aldicarb to female Japanese medaka. Although previous studies indicated that biotransformation may be important in these effects, other dispositional factors may play a role in this scenario. Male and female medaka were separately acclimated to three salinity regimens: 1.

Evaluation of estrogenic activity from a municipal wastewater treatment plant with predominantly domestic input.

The purpose of this study was to survey estrogenic releases from two primarily domestic wastewater treatment plants over three seasons (1996-1999). Mature male channel catfish were maintained at two sites within each WWTP and a reference site for 21 days. Estrogenic activity of effluent was assessed by the Yeast Estrogen Screen (YES) assay (in 1999) and the expression of the female egg yolk precursor protein, vitellogenin (Vtg) in caged male channel catfish (1996-1998).

Effect of 17beta-estradiol and testosterone on the expression of flavin-containing monooxygenase and the toxicity of aldicarb to Japanese medaka, Oryzias latipes.

Previous studies in our laboratory indicated gender differences in salinity-enhanced acute toxicity of aldicarb in Japanese medaka with females being more susceptible. In the current study, the effects of the sex steroids, 17beta estradiol (E2) and testosterone (T) on aldicarb toxicity was examined. Adult Japanese medaka were separated by sex and exposed to 100 microg/l E2 or T for 6 days followed by exposure to the 96-h LC50 (0.

Analyses of organic and inorganic contaminants in Salton Sea fish.

Chemical contamination of fish from the Salton Sea, a quasi-marine lake in Southern California, could adversely impact millions of birds using the Pacific Flyway and thousands of humans using the lake for recreation. Bairdiella icistia (bairdiella), Cynoscion xanthulus (orangemouth corvina), and Oreochromis spp. (tilapia) were sampled from two river mouths and two nearshore areas of the Salton Sea.

Toxicity of select beta adrenergic receptor-blocking pharmaceuticals (B-blockers) on aquatic organisms.

One class of pharmaceutical compounds identified in U.S. and European waters are the B-adrenergic receptor blocking compounds (B-blockers).

Effects of salinity on aldicarb toxicity in juvenile rainbow trout (Oncorhynchus mykiss) and striped bass (Morone saxatilis x chrysops).

Fluctuations in several environmental variables, such as salinity, can influence the interactions between organisms and pollutants in aquatic organisms, and, therefore, affect the toxicity of xenobiotics. In this study, after 2 species of fish, rainbow trout (Oncorhynchus mykiss) and hybrid striped bass (Morone saxatilis x chrysops) were acclimated to 4 salinity regimens of 1.5, 7, 14, and 21 ppt for 1 week and then exposed to 0.

Characterization of salinity-enhanced toxicity of aldicarb to Japanese medaka: sexual and developmental differences.

The effects of salinity, gender, and development on the acute toxicity of aldicarb were examined in the euryhaline fish, Japanese medaka (Oryzias latipes). The 96-h median lethal concentrations (LC50s) at 1.5 parts per thousand (per thousand) salinity were not significantly different between adults and juveniles but larvae were significantly more sensitive to aldicarb.

Toxicity of fipronil and its degradation products to Procambarus sp.: field and laboratory studies.

Fipronil is a phenylpyrazole insecticide that is the active ingredient in the pesticide Icon 6.2 FS which is applied to rice seeds targeting the rice water weevil. An arthropod-selective insecticide, fipronil blocks the GABA-gated chloride channel and is unique in that several of its degradation products have been indicated to be equal or more potent than fipronil.

Effect of salinity on flavin-containing monooxygenase expression and activity in rainbow trout (Oncorhynchus mykiss).

In order to obtain more information about the physiological role(s) of flavin-containing monooxygenases (FMOs) in euryhaline teleost fishes, two experimental series were performed using adult and juvenile rainbow trout (Oncorhynchus mykiss). Cannulated adult trout were exposed to freshwater or 21% seawater for 48 h, whereas juvenile trout were acclimated to one of four different salinities: freshwater, 7%, 14%, or 21% during a 2-week period. FMO expression and activity were determined in red blood cells (RBC), liver, gill, kidney, gut, heart and brain.

Comparative vitellogenic responses in three teleost species: extrapolation to in situ field studies.

Induction of vitellogenin (VTG) was compared among three teleostean species to determine their relative sensitivity of exposure to 17 beta-estradiol (E2). Japanese medaka (Oryzias latipes), sunshine bass (Morone saxatalis x Morone chrysops) and channel catfish (Ictalurus punctatus) were exposed to aqueous concentrations of E2 ranging from 10 to 100,000 ng/l for 21 days. Respective EC50 values for plasma VTG detected by western blot in medaka, catfish and bass were 200, 170 and 1560 ng E2/l.

Estrogenic and CYP1A response of mummichogs and sunshine bass to sewage effluent.

Recent studies demonstrating feminization of effluent-exposed wild-caught male fish in the UK have prompted much research regarding the estrogenic activity of effluent from municipal sewage treatment plants (MSTPs). To investigate the estrogenicity and cytochrome P450 1A (CYP1A) induction potency of MSTP effluent, two species of fish, adult male mummichogs, Fundulus heteroclitus, and juvenile sunshine bass, Morone saxatilis x Morone chrysops, were exposed to un-chlorinated effluent (75% effluent, 25% seawater) from a large MSTP in Yonkers, NY, USA. After a 21-day static-daily (75%) renewal exposure, significant elevations over controls were observed in levels of vitellogenin (VtG) in plasma (1730%) and liver (131%) in effluent-exposed sunshine bass.