The Toxicologist - Society of Toxicology

model compounds from three groups of ubiquitous environmental contaminants:
quaternary ammonium compounds (QACs) used as disinfectants, polycyclic aromatic
hydrocarbons (PAHs) released through use of fossil fuels, and sewage effluent,
on embryos of the Japanese Medaka (*bital*Orizias latipes*eital*), using benzalkonium
chloride (BAC), a high production volume chemical, as a model QAC,
and benzo(α)pyrene (BaP) as a model PAH. We evaluated inhibition of multixenobiotic
resistance (MXR) efflux pumps by quantifying accumulation of calcein-AM,
and developmental toxicity by visually scoring developmental deficits and death.
BAC inhibited MXR pump activity in a dose dependent manner, while BaP had no
effect. Treated sewage effluent also inhibited pump activity, although adding BaP to
effluent abolished the effect. BAC, BaP, and treated sewage effluent caused cranial
facial, skeletal and heart deformities, as well as cardiac edema, all at sublethal concentrations.
Co-exposure to BAC and BaP lead to greater than additive effects,
while co-exposure to BaP had no significant effect on effluent toxicity. That BAC
and sewage effluent are potent inhibitors of MXR pumps indicates exposure to
these compounds can compromise this important defense system that limits cellular
exposure to moderately hydrophobic contaminants or contaminant metabolites.
The ability of these compounds to act as developmental toxicants is also noteworthy
as is the enhanced toxicity observed with BaP exposure.
2392 THE GULF OIL CRISIS: IMPACT ON WHALES.
S. S. Wise 1, 2, 3 , I. Kerr 2, 4 , J. P. Wise 1, 2, 4 , C. F. Wise 1, 2, 4 , J. Wise 1, 2, 4 , C.
Gianios 1, 2, 4 , M. Braun 1, 2, 4 , B. Wallace 4 , I. Glass 4 , R. Walker 4 , C. LaCerte 1, 2, 4 ,
J. McKay 1, 2, 4 , T. Li Chen 1, 2, 4 , J. Martino 1, 2, 4 , G. Chapman 1, 2, 4 , R. Duffy 1, 2, 4 ,
R. Leighton 1, 2, 4 , K. Joyce 1, 2, 4 and J. P. Wise 1, 2, 3 . 1 Wise Laboratory of
Environmental and Genetic Toxicology, University of Southern Maine, Portland, ME,
2 Maine Center for Toxicology and Environmental Health, University of Southern
Maine, Portland, ME, 3 Department of Applied Medical Science, University of
Southern Maine, Portland, ME and 4 Ocean Alliance, Lincoln, MA.
The recent disaster in the Gulf of Mexico resulted in the release of 4.9 million barrels
of oil and 2 million gallons of chemical dispersants. These chemicals were used
in unprecedented ways and amounts and the toxicity of them is poorly understood.
The impact of the oil and dispersants on wildlife in the gulf is of significant concern.
Many animals, including whales, fish and turtles, use the Gulf of Mexico as
calving and spawning grounds. Of particular concern are whales as they are a key
indicator species for the health of our oceans. Two resident populations include
sperm whales and Bryde’s whales which are at particular risk because their population
size is small. To address this crisis, we launched a voyage to assess the impacts
of these pollutants on whale health. The research vessel Odyssey, a 93 foot ketch
equipped with state-of-the art whale tracking, sampling equipment and cell culture
facilities, was used for the voyage. Our scientific approach assessed 1) acute toxicity
based on visual, acoustic and behavioral data, 2) subacute and chronic toxicity by
measuring contaminant levels in whale biopsies, and 3) chronic toxicity by dosing
cultured cells from these animals with petroleum products, dispersants and metals.
In doing this early assessment a baseline set of toxicological data was established to
compare it to similar efforts in the Atlantic as well as future years. The Voyage was
supported by generous donations from the University of Southern Maine, The
Campbell Foundation, The Ocean Foundation, The Marisla Foundation and
Quiznos among many other individual donors and supporters of the Wise
Laboratory and Ocean Alliance.
2393 IMPOSEX IN PLICOPURPURA PANSA
(MOLLUSCA:NEOGASTROPODA) AS A POTENTIAL
MARINE POLLUTION BIOINDICATOR IN NAYARIT
AND SINALOA, MEXICO.
D. Domínguez 1 , A. Patron 2, 1 , L. Robledo 1 , J. Velazquez 1 and B. Quintanilla 3, 1 .
1 Laboratorio de Toxicologia, Universidad Autónoma de Nayarit, Tepic, Nayarit,
Mexico, 2 Fisiologia, Universidad Autonoma de Mexico, DF, Mexico and 3 Toxicologia,
Cinvestav, DF, Mexico.
Imposex is a biomarker of marine species such as gastropods for the presence of a
penis in females, and it has been used worldwide as a biomarker of exposure to
organotin compounds (OTs). Samples of Plicopurpura pansa were collected and examined
to assess the sex ratio, the presence of females with imposex and lipid peroxidation.
These populations were obtained from habitats exhibiting three presuming
different levels of pollution (taking into account their proximity to pollutant
places due to human activity) in Mexico such as Isabel Island and Santa Cruz, in
Nayarit State, as well as Olas Altas, in Sinaloa State. Imposex in female mollusks
was scored as the presence of a pseudopenis. Females and males were classified as
those having normal characteristics. Lipid peroxidation was determined by the
Thiobarbituric acid reactive species. The sex ratio of male:female in Olas Altas and
Santa Cruz were 2:1 in both cases, whereas the sex ratio in Isabel Island was 1:1.
The presence of imposex was 17.24% in Olas Altas, followed by 11.24% in Santa
Cruz and 2.3% in Isabel Island. The lipoperoxidative damage was greater in organ-
514 SOT 2011 ANNUAL MEETING
isms from Olas Altas, followed by Santa Cruz and Isabel Island. According to these
results, the more proximal to pollutant areas, the more oxidated the snails are, and
the more number of imposex cases.
2394 IN VITRO METABOLISM OF DIAZEPAM IN CHANNEL
CATFISH (ICTALURUS PUNCTATUS).
C. Overturf and D. Huggett. University of North Texas, Denton, TX.
Many human pharmaceuticals have been detected in surface waters where they may
bioconcentrate and pose adverse effects to aquatic life. Thus, the following study
examined the in vitro metabolism of diazepam, a model benzodiazepine, in microsomal
fractions of the liver from channel catfish to better determine its bioconcentration
potential. In mammals, diazepam is metabolized to the active intermediates
nordiazepam and temazepam via CYP2C19 and CYP3A4/5, respectively. Both intermediates
are then further metabolized via CYP3A4 to the active metabolite oxazepam.
This study attempted to investigate the loss of parent compound (diazepam),
as well as the generation of active metabolites. Briefly, livers from catfish
(n=3) were harvested and microsomal fractions were prepared. An NADPH regeneration
system was used to simulate phase I reactions and 1000uM diazepam was
added to the system. Samples were taken over a ninety-minute time period and
placed in methanol to stop the reaction. The samples were then processed and analyzed
using LC-MS/MS. A significant loss (14%) of parent compound was measured
within forty-five minutes. Over the same ninety-minute period, both nordiazepam
and temazepam were detected within fifteen minutes. Their formation
plateaued within thirty minutes at 35 parts per billion (ppb) and 102 ppb, respectively.
Interestingly, oxazepam was not detected during the ninety-minute incubation
period. This study shows that microsomal fractions of channel catfish liver
contain the necessary enzymes for the metabolism of diazepam into two pharmacologically
active intermediates. However, the time period may not have been sufficient
for the generation of oxazepam to occur, or catfish enzyme systems may be
unable to generate this secondary metabolite. Further studies will attempt to elucidate
the metabolic pathway of diazepam metabolism and active metabolite formation
in channel catfish.
2395 QUEEN CONCH (STROMBUS GIGAS) REPRODUCTIVE
DYSFUNCTION IN NEARSHORE AREAS OF THE
FLORIDA KEYS – A POSSIBLE LINK TO CU AND ZN.
D. Spade 1 , A. Feswick 1 , R. A. Glazer 2 , D. S. Barber 1 and N. D. Denslow 1 .
1 Center for Environmental and Human Toxicology, University of Florida, Gainesville,
FL and 2 Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation
Commission, Marathon, FL.
In the Florida Keys, queen conchs (Strombus gigas) residing offshore (OS) develop
gonads and are capable of reproduction, while near-shore (NS) conchs lack sufficient
gonadal development for reproduction. A custom queen conch microarray
(GEO accession GPL8934) was used to study differences in gene expression between
OS and NS conch. 257 transcripts were differentially regulated in testis,
1368 in ovary, and 1153 in the digestive gland of females (ANOVA, p