ORCID Profile
0000-0002-7808-8159
Current Organisation
James Cook University
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Publisher: Springer Science and Business Media LLC
Date: 21-05-2012
Publisher: Wiley
Date: 28-03-2020
DOI: 10.1111/ACV.12583
Publisher: Elsevier BV
Date: 10-2013
DOI: 10.1016/J.AQUATOX.2013.08.011
Abstract: The 2010 Deepwater Horizon disaster in the Gulf of Mexico was the largest oil spill in United States history. Crude oils are highly toxic to developing fish embryos, and many pelagic fish species were spawning in the northern Gulf in the months before containment of the damaged Mississippi Canyon 252 (MC252) wellhead (April-July). The largest prior U.S. spill was the 1989 grounding of the Exxon Valdez that released 11 million gallons of Alaska North Slope crude oil (ANSCO) into Prince William Sound. Numerous studies in the aftermath of the Exxon Valdez spill defined a conventional crude oil injury phenotype in fish early life stages, mediated primarily by toxicity to the developing heart. To determine whether this type of injury extends to fishes exposed to crude oil from the Deepwater Horizon - MC252 incident, we used zebrafish to compare the embryotoxicity of ANSCO alongside unweathered and weathered MC252 oil. We also developed a standardized protocol for generating dispersed oil water-accommodated fractions containing microdroplets of crude oil in the size range of those detected in subsurface plumes in the Gulf. We show here that MC252 oil and ANSCO cause similar cardiotoxicity and photo-induced toxicity in zebrafish embryos. Morphological defects and patterns of cytochrome P450 induction were largely indistinguishable and generally correlated with polycyclic aromatic compound (PAC) composition of each oil type. Analyses of embryos exposed during different developmental windows provided additional insight into mechanisms of crude oil cardiotoxicity. These findings indicate that the impacts of MC252 crude oil on fish embryos and larvae are consistent with the canonical ANSCO cardiac injury phenotype. For those marine fish species that spawned in the northern Gulf of Mexico during and after the Deepwater Horizon incident, the established literature can therefore inform the assessment of natural resource injury in the form of potential year-class losses.
Publisher: Association of Biomolecular Resource Facilities
Date: 07-2014
Publisher: Elsevier BV
Date: 09-2009
DOI: 10.1016/J.MARGEN.2009.11.001
Abstract: Lactate dehydrogenase-B (ldh-b) encodes a metabolic enzyme (LDH-B) which plays an important role in maintaining aerobic performance and in thermal acclimation and/or adaptation of fish. As the first step in understanding the effect this enzyme has on the ability of tropical coral reef fishes to cope with thermal stress, we characterized both coding and non-coding regions of ldh-b in two congeneric perciformes, Plectropomus leopardus and Plectropomus laevis. Ldh-b was 4666 and 4539bp in length in P. leopardus and P. laevis, respectively, with coding regions comprising 1005bp in both species. We report a high level of sequence homology between the coding regions of ldh-b in these two species, with 98.1% identity of nucleotides corresponding to 100% amino acid identity between the deduced protein sequences. Comparison between non-coding (intron) regions of both species revealed the presence of several indels, despite the high level of homology observed (95.9% identity of intron nucleotides). Potential regulatory motifs and elements, including twenty-six simple sequence repeat motifs (mono-, di-, tri- and tetranucleotide) and twenty-three putative microRNA elements are identified within the introns of both species, further supporting recent demonstrations that such short motifs and elements exhibit widespread positioning throughout non-coding regions of the genome. This novel characterization of ldh-b in these two coral reef fishes allows for a wide range of future studies (e.g. analytical comparisons of ldh-b and LDH-B among different fish genera from different thermal environments and habitats).
Publisher: American Chemical Society (ACS)
Date: 15-01-2016
Abstract: Coal tar sealcoats applied to asphalt surfaces in North America, east of the Continental Divide, are enriched in petroleum-derived compounds, including polycyclic aromatic hydrocarbons (PAHs). The release of PAHs and other chemicals from sealcoat has the potential to contaminate nearby water bodies, reducing the resiliency of aquatic communities. Despite this, relatively little is known about the aquatic toxicology of sealcoat-derived contaminants. We assessed the impacts of stormwater runoff from sealcoated asphalt on juvenile coho salmon (Oncorhynchus kisutch) and embryo-larval zebrafish (Danio rerio). We furthermore evaluated the effectiveness of bioretention as a green stormwater method to remove PAHs and reduce lethal and sublethal toxicity in both species. We applied a coal tar sealcoat to conventional asphalt and collected runoff from simulated rainfall events up to 7 months postapplication. Whereas sealcoat runoff was more acutely lethal to salmon, a spectrum of cardiovascular abnormalities was consistently evident in early life stage zebrafish. Soil bioretention effectively reduced PAH concentrations by an order of magnitude, prevented mortality in juvenile salmon, and significantly reduced cardiotoxicity in zebrafish. Our findings show that inexpensive bioretention methods can markedly improve stormwater quality and protect fish health.
Publisher: Oxford University Press (OUP)
Date: 24-10-2015
Publisher: Canadian Science Publishing
Date: 07-2010
DOI: 10.1139/F10-047
Abstract: We investigated how thermal stress may alter the locomotor phenotype of barramundi, Lates calcarifer , from genetically distinct northern (low latitude) and southern (high latitude) populations in tropical Australia. Following early growth and development under native (25 °C and 30 °C) and non-native (20 °C and 35 °C) temperatures, we observed distinct differences in the swimming performance of northern and southern in iduals that were consistent with expectations based on local thermal adaptation. Southern population fish exhibited significantly faster swimming speeds (32.10 ± 0.33 cm·s –1 , mass-adjusted mean ± 95% confidence limit) than their northern counterparts (28.58 ± 0.64 cm·s –1 ) under cold-stress (20 °C) conditions. Conversely, northern population fish performed significantly better (51.63 ± 2.1 cm·s –1 ) than their southern counterparts (44.18 ± 3.11 cm·s –1 ) under heat-stress (35 °C) conditions. We conclude that L. calcarifer display locomotor phenotypes thermally adapted to their local environment, with early growth under non-native temperatures leading to significantly reduced phenotypic fitness.
Publisher: Springer Science and Business Media LLC
Date: 26-03-2019
DOI: 10.1038/S41598-019-41517-2
Abstract: Effective border control relies on stringent biosecurity protocols to detect and prevent introductions of exotic pests and diseases. Detection of pathogens and parasites in the live ornamental fish trade using environmental DNA (eDNA) techniques has the potential to improve current biosecurity practices. We examined water s les from 11 target consignments (cyprinids susceptible to Dactylogyrus spp. infections) and seven non-target fish consignments (non-cyprinids, not susceptible to Dactylogyrus spp. infections) imported from Southeast Asia to Australia for the presence of eDNA from five Dactylogyrus species (Monogenea: Dactylogyridae). A four-step predictive framework was used to predict putative positive and putative negative detections from quantitative PCR assays. Both target and non-target consignments were positive for Dactylogyrus spp. eDNA as confirmed by Sanger sequencing. Positive detections for Dactylogyrus spp. eDNA in non-target fish consignments demonstrates the possibility of source water contamination, limiting the applicability of eDNA screening methods at border control. This study suggests that screening for parasite eDNA within ornamental fish consignments should be tested during pre-export quarantine periods to avoid false positive detections at border control. Lastly, the proposed predictive framework has a broad utility for minimizing false positive and false negative eDNA detections of aquatic organisms.
Publisher: American Chemical Society (ACS)
Date: 19-01-2016
Abstract: Urban stormwater runoff is a globally significant threat to the ecological integrity of aquatic habitats. Green stormwater infrastructure methods such as bioretention are increasingly used to improve water quality by filtering chemical contaminants that may be harmful to fish and other species. Ubiquitous ex les of toxics in runoff from highways and other impervious surfaces include polycyclic aromatic hydrocarbons (PAHs). Certain PAHs are known to cause functional and structural defects in developing fish hearts. Therefore, abnormal heart development in fish can be a sensitive measure of clean water technology effectiveness. Here we use the zebrafish experimental model to assess the effects of untreated runoff on the expression of genes that are classically responsive to contaminant exposures, as well as heart-related genes that may underpin the familiar cardiotoxicity phenotype. Further, we assess the effectiveness of soil bioretention for treating runoff, as measured by prevention of both visible cardiac toxicity and corresponding gene regulation. We find that contaminants in the dissolved phase of runoff (e.g., PAHs) are cardiotoxic and that soil bioretention protects against these harmful effects. Molecular markers were more sensitive than visible toxicity indicators, and several cardiac-related genes show promise as novel tools for evaluating the effectiveness of evolving stormwater mitigation strategies.
Publisher: Springer Science and Business Media LLC
Date: 10-12-2015
DOI: 10.1038/SREP17326
Abstract: Crude oils from distinct geological sources worldwide are toxic to developing fish hearts. When oil spills occur in fish spawning habitats, natural resource injury assessments often rely on conventional morphometric analyses of heart form and function. The extent to which visible indicators correspond to molecular markers for cardiovascular stress is unknown for pelagic predators from the Gulf of Mexico. Here we exposed mahi ( Coryphaena hippurus ) embryos to field-collected crude oil s les from the 2010 Deepwater Horizon disaster. We compared visible heart defects (edema, abnormal looping, reduced contractility) to changes in expression of cardiac-specific genes that are diagnostic of heart failure in humans or associated with loss-of-function zebrafish cardiac mutants. Mahi exposed to crude oil during embryogenesis displayed typical symptoms of cardiogenic syndrome as larvae. Contractility, looping and circulatory defects were evident, but larval mahi did not exhibit downstream craniofacial and body axis abnormalities. A gradation of oil exposures yielded concentration-responsive changes in morphometric and molecular responses, with relative sensitivity being influenced by age. Our findings suggest that 1) morphometric analyses of cardiac function are more sensitive to proximal effects of crude oil-derived chemicals on the developing heart and 2) molecular indicators reveal a longer-term adverse shift in cardiogenesis trajectory.
Location: United States of America
No related grants have been discovered for Richard Edmunds.