6. Alderman, SL; Lin, F; Gillis, TE; Farrell, AP; Kennedy, CJ. (2018) Developmental and latent effects of diluted bitumen exposure on early life stages of sockeye salmon (Oncorhynchus nerka).Aquat. Toxicol. 202 Developmental and latent effects of diluted bitumen exposure on early life stages of sockeye salmon (Oncorhynchus nerka)
Bitumen; Crude oil; Fish; Development; Toxicity; Morphogenesis
The early life stages of Pacific salmon are at risk of environmental exposure to diluted bitumen (dilbit) as Canada's oil sands industry continues to expand. The toxicity and latent effects of dilbit exposure were assessed in sockeye salmon (Oncorhynchus nerka) exposed to water-soluble fractions of dilbit (WSFd) from fertilization to the swim-up stage, and then reared in clean water for 8 months. Mortality was significantly higher in WSFd-exposed embryos, with cumulative mortality up to 4.6-fold higher in exposed relative to unexposed embryos. The sublethal effects of WSFd exposure included transcriptional up-regulation of cypla, a concentration-dependent delay in the onset and progression of hatching, as well as increased prevalence of developmental deformities at total polycyclic aromatic hydrocarbon (TPAH) concentrations >= 35 mu g L-1. Growth and body composition were negatively affected by WSFd exposure, including a concentration-specific decrease in soluble protein concentration and increases in total body lipid and triglyceride concentrations. Mortality continued during the first 2 months after transferring fish to clean water, reaching 53% in fish exposed to 100 mu g L-1 TPAH; but there was no latent impact on swimming performance, heart mass, or heart morphology in surviving fish after 8 months. A latent effect of WSFd exposure on brain morphology was observed, with fish exposed to 4 mu g L-1 TPAH having significantly larger brains compared to other treatment groups after 8 months in clean water. This study provides comprehensive data on the acute, sub-chronic, and latent impacts of dilbit exposure in early life stage sockeye, information that is critical for a proper risk analysis of the impact of a dilbit spill on this socioeconomically important fish species. DOI PubMed
5. Marlatt, VL; Sherrard, R; Kennedy, CJ; Elphick, JR; Martyniuk, CJ. (2016) Application of molecular endpoints in early life stage salmonid environmental biomonitoring.Aquatic Toxicology 173: 178-191 Application of molecular endpoints in early life stage salmonid environmental biomonitoring
Environmental monitoring; Gene expression; Metals; PAH; Salmonid; Development
Molecular endpoints can enhance existing whole animal bioassays by more fully characterizing the biological impacts of aquatic pollutants. Laboratory and field studies were used to examine the utility of adopting molecular endpoints for a well-developed in situ early life stage (eyed embryo to onset of swim-up fry) salmonid bioassay to improve diagnostic assessments of water quality in the field. Coastal cutthroat trout (Oncorhynchus clarki clarki) were exposed in the laboratory to the model metal (zinc, 40 mu g/L) and the polycyclic aromatic hydrocarbon (pyrene, 100 mu g/L) in water to examine the resulting early life stage salmonid responses. In situ field exposures and bioassays were conducted in parallel to evaluate the water quality of three urban streams in British Columbia (two sites with anthropogenic inputs and one reference site). The endpoints measured in swim-up fry included survival, deformities, growth (weight and length), vitellogenin (vtg) and metallothionein (Mt) protein levels, and hepatic gene expression (e.g., metallothioneins [mta and mtb], endocrine biomarkers [vtg and estrogen receptors, esr] and xenobiotic-metabolizing enzymes [cytochrome P4501A3, cyp1a3 and glutathione transferases, gstk]). No effects were observed in the zinc treatment, however exposure of swim-up fry to pyrene resulted in decreased survival, deformities and increased estrogen receptor alpha (er1) mRNA levels. In the field exposures, xenobiotic-metabolizing enzymes (cyp1a3, gstk) and zinc transporter (zntBigM103) mRNA were significantly increased in swim-up fry deployed at the sites with more anthropogenic inputs compared to the reference site. Cluster analysis revealed that gene expression profiles in individuals from the streams receiving anthropogenic inputs were more similar to each other than to the reference site. Collectively, the results obtained in this study suggest that molecular endpoints may be useful, and potentially more sensitive, indicators of site-specific contamination in real-world, complex exposure scenarios in addition to whole body morphometric and physiological measures. (C) 2016 Elsevier B.V. All rights reserved. DOI
4. Shelley, LK; Osachoff, HL; van Aggelen, GC; Ross, PS; Kennedy, CJ. (2013) Alteration of immune function endpoints and differential expression of estrogen receptor isoforms in leukocytes from 17 beta-estradiol exposed rainbow trout (Oncorhynchus mykiss).General and Comparative Endocrinology 180: 24-32 Alteration of immune function endpoints and differential expression of estrogen receptor isoforms in leukocytes from 17 beta-estradiol exposed rainbow trout (Oncorhynchus mykiss)
PERIPHERAL-BLOOD LEUKOCYTES; FLOW-CYTOMETRIC ANALYSIS; PERSONAL CARE PRODUCTS; GENE-EXPRESSION; IN-VITRO; CYPRINUS-CARPIO; ENVIRONMENTAL ESTROGENS; DISEASE RESISTANCE; TERM EXPOSURE; COMMON CARP
While the endocrine system is known to modulate immune function in vertebrates, the role of 17 beta-estradiol (E2) in cellular immune function of teleosts is poorly understood. The cellular and molecular responses of juvenile rainbow trout (Oncorhynchus mykiss) to E2 treatment were evaluated by exposing fish to 0.47 +/- 0.02 mu g/L E2 (mean +/- SEM) for either 2 or 7 d, with a subsequent 14 d recovery period. After 2 and 7 d of exposure to E2, hematocrit was significantly lower than in control fish. Lipopolysaccharide-induced lymphocyte proliferation was elevated on day 2 and concanavalin A-induced lymphocyte proliferation was reduced following 7 d of E2 exposure. Four estrogen receptor (ER) transcripts were identified in purified trout head kidney leukocytes (HKL) and peripheral blood leukocytes (PBL). While the mRNA abundance of ER beta 1 and ER beta 2 was unaffected by treatment, ER alpha 1 was up-regulated in HKL and PBL following 7 d of E2 exposure. ER alpha 2 was up-regulated in HKL after 7 d of E2 exposure, but down-regulated in PBL after 2 and 7 d of treatment. All parameters that were altered during the E2 exposure period returned to baseline levels following the recovery period. This study reports the presence of the full repertoire of ERs in purified HKL for the first time, and demonstrates that ER alpha transcript abundance in leukocytes can be regulated by waterborne E2 exposure. It also demonstrated that physiologically-relevant concentrations of E2 can modulate several immune functions in salmonids, which may have widespread implications for xenoestrogen-associated immunotoxicity in feral fish populations inhabiting contaminated aquatic environments. (C) 2012 Elsevier Inc. All rights reserved. DOI
3. Lee, YS; Otton, SV; Campbell, DA; Moore, MM; Kennedy, CJ; Gobas, FAPC. (2012) Measuring In Vitro Biotransformation Rates of Super Hydrophobic Chemicals in Rat Liver S9 Fractions Using Thin-Film Sorbent-Phase Dosing.Environmental Science & Technology 46: 410-418 Measuring In Vitro Biotransformation Rates of Super Hydrophobic Chemicals in Rat Liver S9 Fractions Using Thin-Film Sorbent-Phase Dosing
Methods for rapid and cost-effective assessment of the biotransformation potential of very hydrophobic and potentially bioaccumulative chemicals in mammals are urgently needed for the ongoing global evaluation of the environmental behavior of commercial chemicals. We developed and tested a novel solvent-free, thin-film sorbent-phase in vitro dosing system to measure the in vitro biotransformation rates of very hydrophobic chemicals in male Sprague-Dawley rat liver S9 homogenates and compared the rates to those measured by conventional solvent-delivery dosing. The thin-film sorbent-phase dosing system using ethylene vinyl acetate coated vials was developed to eliminate the incomplete dissolution of very hydrophobic substances in largely aqueous liver homogenates, to determine biotransformation rates at low substrate concentrations, to measure the unbound fraction of substrate in solution, and to simplify chemical analysis by avoiding the difficult extraction of test chemicals from complex biological matrices. Biotransformation rates using sorbent-phase dosing were 2-fold greater than those measured using solvent-delivery dosing. Unbound concentrations of very hydrophobic test chemicals were found to decline with increasing S9 and protein concentrations, causing measured biotransformation rates to be independent of S9 or protein concentrations. The results emphasize the importance of specifying both protein content and unbound substrate fraction in the measurement and reporting of in vitro biotransformation rates of very hydrophobic substances, which can be achieved in a thin-film sorbent-phase dosing system. DOI PubMed
2. Waliwitiya, R; Nicholson, RA; Kennedy, CJ; Lowenberger, CA. (2012) The Synergistic Effects of Insecticidal Essential Oils and Piperonyl Butoxide on Biotransformational Enzyme Activities in Aedes aegypti (Diptera: Culicidae).Journal of Medical Entomology 49: 614-623 The Synergistic Effects of Insecticidal Essential Oils and Piperonyl Butoxide on Biotransformational Enzyme Activities in Aedes aegypti (Diptera: Culicidae)
ethoxyresorufin O-deethylase; glutathione S-transferase; esterase; essential oil; Ae. Aegypti
The biochemical mechanisms underlying the increased toxicity of several plant essential oils (thymol, eugenol, pulegone, terpineol, and citronellal) against fourth instar of Aedes aegypti L. when exposed simultaneously with piperonyl butoxide (PBO) were examined. Whole body biotransformational enzyme activities including cytochrome P450-mediated oxidation (ethoxyresorufin O-dethylase [EROD]), glutathione S-transferase (GST), and beta-esterase activity were measured in control, essential oil-exposed only (single chemical), and essential oil + PBO (10 mg/liter) exposed larvae. At high concentrations, thymol, eugenol, pulegone, and citronellal alone reduced EROD activity by 5-25% 16 h postexposure. Terpineol at 10 mg/liter increased EROD activity by 5 +/- 1.8% over controls. The essential oils alone reduced GST activity by 3-20% but PBO exposure alone did not significantly affect the activity of any of the measured enzymes. All essential oils in combination with PBO reduced EROD activity by 58-76% and reduced GST activity by 3-85% at 16 h postexposure. This study indicates a synergistic interaction between essential oils and PBO in inhibiting the cytochrome P450 and GST detoxification enzymes in Ae. aegypti. DOI
1. Waliwitiya, R., Kennedy, C., and Lowenberger, C. (2009) Larvicidal and antiovipositional activity of monoterpenoids and rosemary oil to the yellow fever mosquito Aedes aegypti (Diptera: Culicidae).Pest Management Science 65: 241-248. Larvicidal and antiovipositional activity of monoterpenoids and rosemary oil to the yellow fever mosquito Aedes aegypti (Diptera: Culicidae)
Aedes aegypti, acute toxicity, essential oils, larvicides, monoterpenoids, oviposition, piperonyl butoxide
Aedes aegypti L. is the major vector of dengue fever and dengue hemorrhagic fever. In an effort to find effective tools for control programs to reduce mosquito populations, the authors assessed the acute toxicities of 14 monoterpenoids, trans-anithole and the essential oil of rosemary against different larval stages of Ae. aegypti. The potential for piperonyl butoxide (PBO) to act as a synergist for these compounds to increase larvicidal activity was also examined, and the oviposition response of gravid Ae. aegypti females to substrates containing these compounds was evaluated in behavioral bioassays.
RESULTS: Pulegone, thymol, eugenol, trans-anithole, rosemary oil and citronellal showed high larvicidal activity against all larval stages of Ae. aegypti (LC50 values 10.3-40.8 mg L-1). The addition of PBO significantly increased the larvicidal activity of all test compounds (3-250-fold). Eugenol, citronellal, thymol, pulegone, rosemary oil and cymene showed oviposition deterrent and/or repellent activities, while the presence of borneol, camphor and -pinene increased the number of eggs laid in test containers.
CONCLUSIONS: This study quantified the lethal and sublethal effects of several phytochemical compounds against all larval stages of Aedes aegypti, providing information that ultimately may have potential in mosquito control programs through acute toxicity and/or the ability to alter reproductive behaviorsWebsite DOI
