The Toxicologist - Society of Toxicology

2401 BEHAVIORAL, REPRODUCTIVE, AND GENOMIC
RESPONSES TO NEUROPHARMACEUTICALS AT
SUBCLINICAL CONCENTRATIONS FOUND IN THE
ENVIRONMENT: FISH AS INDICATORS OF
POTENTIAL HUMAN CONSEQUENCES OF LOW-DOSE
EXPOSURES.
R. Klaper. School of Freshwater Sciences, University of Wisconsin Milwaukee,
Milwaukee, WI. Sponsor: R. Hutz.
Pharmaceuticals and personal care products (PPCP) have been found in surface waters
globally, and have now been found in drinking water, popular fish species that
are regularly consumed by humans. Although not acutely toxic at these environmental
levels the sublethal impacts from chronic exposures are not well understood.
Fluoxetine, a highly prescribed selective serotonin reuptake inhibitor, is a commonly
found PPCP in environmental samples. We tested the effects of environmentally
relevant concentrations on the reproduction, behavior, and gene expression
in the brain of the toxicological model species Pimephales promelas (fathead
minnow) during a 4 week chronic exposure. P. promelas, is the current model
species for environmental toxicology and can provide information on potential impacts
on humans due to the conservation of biochemical pathways. Our data
demonstrate that the impacts of fluoxetine at low-level exposures is both dose and
time dependent. Fluoxetine influences aggression, response to key stimuli, such as
predators, food and mates, which significantly decreases with exposure; and obsessive
behavior patterns, exemplified by next cleaning, quantifiably increase.
Fluoxetine concentrations as low as 1 μg/l were found to significantly impact the
behavior of the fathead minnow. The response in fish is similar to that of mammals,
where early interference with serotonin levels increases depression and anxiety.
Some have attributed these changes to merely serotonin regulation and potential
endocrine responses, however we demonstrate in this study that genomic pathways
associated with cell adhesion, neurogenesis, and plasticity in the brain are impacted
by SSRI’s at these levels and hormones are not. This is one of the first studies to examine
how these pathways may be impacted by low-level exposures and the duration
of exposure.
2402 TOXICOLOGICAL MECHANISMS OF AZASPIRACID:
AN EMERGING ALGAL TOXIN IN U.S. WATERS.
M. Twiner 1 , P. Hess 2 , R. El-Ladki 1 , S. Butler 1 and G. Doucette 3 . 1 Natural
Sciences, University of Michigan, Dearborm, MI, 2 Département Environnement,
Microbiologie & Phycotoxines, IFREMER, Nantes, France and 3 Marine Biotoxins
Program, NOAA/National Ocean Service, Charleston, SC.
Azaspiracids (AZA) are an algal toxin group known to accumulate in shellfish and
represent an emerging human health risk. Although monitored and regulated in
many European and Asian countries, there are no regulatory requirements or standards
in many of the other countries where AZAs have recently been identified. In
Puget Sound (WA, USA), the presence of AZAs in shellfish and in samples collected
using solid phase adsorption toxin tracking (SPATT) disks provide compelling
evidence of this emerging risk. Efforts are now underway to better define
the effects and mechanism of action for the various AZA analogues. Our investigations
have employed in vitro cell models to characterize the potential toxicological
impacts of AZA1, AZA2 and AZA3, and the use of DNA microarrays (i.e., gene
chips) has yielded valuable insights as to possible biochemical pathways targeted by
AZA1. Studies with several mammalian cell types yielded low nanomolar EC 50 cytotoxicity
values, making the AZAs one of the most cytotoxic algal toxin groups
known. Our current focus is on further defining the specific mechanism of action,
which appears to involve inhibition of cholesterol biosynthesis. Future experiments
will continue to characterize analogue-specific cellular and biochemical responses as
well as the toxicological effects of AZAs on various model organisms such as bacteria,
developing brine shrimp, and fish.
2403 SEASONAL DYNAMICS OF COLORED DISSOLVED
ORGANIC MATTER IN THE LENA, MACKENZIE, AND
YENESEI RIVERS.
K. E. Goodman 2 , S. A. Walker 1 and R. W. Amon 1 . 1 Marine Science, Texas A&M
University, Galveston, TX and 2 Natural Sciences, Albany State University, Albany,
GA. Sponsor: L. Wrensford.
In this study, colored dissolved organic matter (CDOM) was evaluated in three of
the largest Arctic rivers including: the Lena, Mackenzie, and Yenesei to determine if
we can distinguish between the different rivers and fingerprint them in the Arctic
Ocean based on their CDOM signal. Excitation Emission Matrix (EEM) spectroscopy
coupled to Parallel Factor Analysis (PARAFAC), a multi-linear regression
516 SOT 2011 ANNUAL MEETING
technique was used to identify the different terrestrial and protein components
within each river over the time frame of 2004-2006. We hypothesize that the highest
amount of CDOM within these rivers will occur for the month of June (during
spring freshet) and the lowest amount of CDOM will occur for the other two
months measured (March and August). To test this hypothesis, we analyzed samples
for these three months over the time scale mentioned above to observe the seasonal
variability of the rivers. Data compiled from these rivers were later composed into a
preliminary PARAFAC model in which a prominent terrestrial and protein component
were identified as c1 and c5. Results show that for all samples studied, the terrestrial
component had a higher intensity than the protein component. Within
each component, it was shown that the Lena River had the highest intensity
amongst the rivers shown, meaning that it had the highest CDOM concentration
as well. For each river shown, the change in its CDOM intensity was apparent before
and after the peak season with highest intensities being in June and the lowest
occurring in March and August. These results suggest that seasonal variability in the
rivers is indeed related to the spring freshet during which more organic matter is
discharged from those rivers. Component 1 (c1) identified in the PARAFAC model
was also identified in coastal waters of the Canadian Basin indicating that terrestrial
components derived from river data can be used as tracers in the Arctic Ocean.
2404 EFFECTS OF PCB CONTAMINATION ON ACTIVITIES
OF OXIDATIVE STRESS ENZYMES IN S.
ATROMACULATUS LIVERS.
K. Shortt 1 , D. Sparks 2 , D. Millsap 2 and J. B. Watkins 1 . 1 Indiana University,
Bloomington, IN and 2 U.S. Fish and Wildlife, Bloomington, IN.
Water source contamination with polychlorinated biphenyls (PCBs) commonly affects
basic cellular functions of exposed organisms. The purpose of this study was
to determine whether PCB contamination causes oxidative stress in the liver of central
Indiana native creek chubs (Semolitus atromaculatus). The impact of PCB contamination
was measured by examining the activity of indicators of oxidative stress
in S. atromaculatus livers. Sampled streams were sorted into reference (0.0-0.1 ppm
fish tissue), low PCB (0.1-0.5 ppm fish tissue), medium PCB (0.6-1.0 ppm) and
high PCB (>1.0 ppm) comparison groups. Additional fish were collected from one
high level PCB site after remediation. The fish were collected using standard electroshock
techniques during the mating season. The livers were removed, frozen
with liquid nitrogen, and prepared as 5% cytosols for analysis. The activities of superoxide
dismutase, catalase, glutathione peroxidase, and glutathione reductase
were determined spectrophotometrically. PCB contamination was found to have
significant adverse effects on the hepatic activities of glutathione reductase and peroxidase
of the fish from the medium concentration streams. Activities of catalase
and glutathione reductase were significantly different in the high PCB concentration
streams. The activity of glutathione peroxidase in the high concentration
group approached significance (p= 0.078). Hepatic enzyme activities of creek chubs
from remediated sites were similar to those from reference sites. Further analysis of
the effects of PCBs on lifespan and health of S. atromaculatus is needed.
2405 THE TOXIC EFFECTS OF CHROMIUM COMPOUNDS
IN NORTH ATLANTIC RIGHT WHALE AND SPERM
WHALE CELLS.
T. Li Chen 1, 2, 3 , J. Martino 1, 2, 3 , S. S. Wise 1, 2, 3 , C. LaCerte 1, 2, 3 , F. Shaffiey 1, 2 ,
H. Xie 1, 2, 3 , A. L. Holmes 1, 2, 3 , K. McPhearson 1, 2 , I. Kerr 4 , R. Payne 4 , S. D.
Kraus 5 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, 4 Ocean Alliance, Lincoln, MA and 5 Edgerton Research Laboratory, New
England Aquarium, Boston, MA.
Analysis of heavy metals in skin biopsies collected from North Atlantic right whales
and sperm whales shows that both species are exposed to relatively high levels of
chromium (Cr), 7.1 ± 0.8 and 8.8 ± 0.9 ppm, respectively. We tested the toxic effects
of the most biologically relevant Cr valence states, trivalent and hexavalent
chromium compounds [Cr(III) and Cr(VI), respectively] on whale skin cells grown
in culture. Cr(VI) compounds are well known human carcinogens and skin irritants,
whereas Cr(III) compounds are believed to be non-toxic to humans. Our results
show that hexavalent compounds cause both cell death and DNA damage in
whale cells at levels that are comparable to the concentrations that affect human
cells. They also show that at the levels comparable to those we found in whales,
Cr(III) induces cell death. Our study suggests that both Cr(III) and Cr(VI) may be
a health concern for the whales. We are currently investigating the potential genotoxic
effects of the trivalent Cr compounds. This work was supported by Grant
number NA03NMF4720478 from the United States Department of Commerce,
NOAA (J.P.W.), NIEHS grant ES10838 (J.P.W.) and the Maine Center for
Toxicology and Environmental Health.