Natalie Karouna-Renier, Ph.D.
Natalie Karouna-Renier is a Research Ecologist at the USGS Patuxent Wildlife Research Center, in Beltsville, MD, where she is the leader of the Molecular Toxicology Laboratory. Natalie's expertise lays in understanding, detecting, and predicting the effects of environmental stressors on birds and other wildlife, primarily at the molecular and biochemical level.
- PhD in Biology from Rensselaer Polytechnic Institute, Troy, NY
- MS in Toxicology from the University of Maryland
- BS in Biology from Colgate University, Hamilton, NY
Research in Natalie's lab centers on the identification and application of novel genomic and non-genomic indicators for identifying toxicological responses in wildlife. The effects of endocrine active and genotoxic compounds, and the development of tools to assess and predict differences in species sensitivity are of particular interest and focus. Natalie has also conducted multiple studies investigating higher level effects of contaminants on wildlife, fish, aquatic invertebrates, and humans. http://www.usgs.gov/ecosystems/genetics_genomics/environmental_toxicology_birds.html
Science and Products
The Challenge: Neonicotinoid pesticides act as agonists of nicotinic acetylcholine receptors (nAChRs) and are designed to be lethal to insects while theoretically posing little to no threat to vertebrates. The perceived safety of neonicotinoids has led to a sharp increase in their use in the United States and globally, since they were first introduced in 1994. The use of the neonicotinoid imidacloprid in the United States has increased 166% since 2009, from 0.75 to roughly 2 million pounds, and its use as seed treatment represents approximately 56% of total annual usage. Although neonicotinoids are designed to be selectively toxic to invertebrates, effects on other organisms are being reported. However, toxicity information on birds is particularly limited. Birds are primarily exposed to neonicotinoids orally (feeding, preening), by inhalation, or dermally depending on whether the pesticide is applied by aerial spraying or as a seed coating.
The Challenge: Traditionally, bee identification has relied on taxonomic methods centered on descriptions of morphological differences between species. However, for many species, separate keys are required for identifying adult males and females and immature life stages. These keys are commonly unavailable. The lack of distinguishing morphological characters useful for separating closely related species is a common problem in many bee species, reducing the effectiveness and completeness of bee diversity surveys and general biological studies of bees.
The Challenge: Endocrine active chemicals (EAC) are known to interfere with hormonally regulated physiological processes, thereby affecting signaling in the hypothalamic-pituitary-gonadal-liver (HPGL) axis and commonly resulting in reproductive dysfunction. Computational models that relate hormonal and genomic biomarkers within the HPGL axis to the reproductive cycle and ecologically relevant endpoints have been developed for fish; however, no similar model is available for birds. These models are very useful for evaluating how EAC-induced changes in physiological systems enhance or inhibit embryonic development, reproduction, and growth.
The Challenge: Wild birds are exposed throughout their lives to natural and synthetic chemicals that are present in the environment, many of which interfere with the animal’s physiological and developmental systems. Relative concentrations, routes, frequency, and the environment in which chemical exposure occurs will determine to a large extent the bird’s response. Well-designed avian field studies conducted on site are expensive, both in terms of personnel and funding. In order to address specific field exposures and/or focus on variables of particular concern, pen studies can be conducted on a smaller scale. The Japanese quail (Coturnix japonica, JQ) has been used as a model for gallinaceous birds in research because it exhibits a short generation time of 53-74 days and all stages of its development can be maintained and tested in captivity under controlled laboratory pen conditions. As we move towards minimizing the numbers of animals used for research, the role of the JQ as an appropriate model for avian wildlife in ecotoxicological studies is being redefined.
The Challenge: Mercury is a highly toxic element found throughout our environment. Although it occurs naturally in some environments, human industrial pollution has greatly increased the amount of mercury and the range of environments in which mercury is found. Recent studies have confirmed clear differences in the sensitivity of various bird species to methylmercury. Because the causes of these differences are unknown, prediction of mercury sensitivity is difficult in birds that have not or cannot be studied in the lab. Therefore, a method is needed that can predict sensitivity to mercury in poorly studied birds and can help identify susceptible populations.
The Challenge: Short-Chain Chlorinated Paraffins (SCCPs) are complex technical mixtures of polychlorinated n-alkanes used in lubricants and coolants in metalworking, as flame retardants, and in paints, adhesives, sealants, textiles and polymeric materials, plastics and rubber. SCCPs are of concern because they are globally transported, bioaccumulate in wildlife and humans, and are environmentally persistent. Their toxicity has been demonstrated in multiple species and their presence has been detected in wild birds and their eggs far from primary manufacturing centers. However, few controlled studies have been conducted to determine the potential hazard and risk that SCCPs pose to free-ranging birds.
The Challenge: The use of flame retardants (FRs) as additives in a variety of consumer use products, including plastics, textiles, and electronics, is projected to continue and increase for the foreseeable future. Because of unanticipated environmental problems, some FRs have either been banned, restricted, or are being phased-out and replaced by other new and presumably safer FRs. Regrettably, many of these alternative FRs are found to bioaccumulate in wildlife tissues, including in bird eggs, suggesting exposure through maternal deposition. However, few data are available on the potential adverse effects in exposed animals.
The Challenge: Neonicotinoids are now the most widely applied class of insecticides in the United States, and are predominantly used in the form of seed treatments. Compared to invertebrates, neonicotinoids are less toxic to wildlife, although genotoxic, cytotoxic, immunological, behavioral and reproductive effects have been reported in studies with birds. At present, little is known about the pharmacokinetics (absorption, distribution, metabolism and excretion) of these pesticides in birds, which can dictate and affect the timecourse of their toxicity. Such information will greatly assist in evaluating the hazard and risk of neonicotinoid seed coatings to wild birds.
The Challenge: Agricultural, industrial and urban activities have had major effects on waterbirds in Chesapeake and Delaware Bays. Some legacy pollutants (PCBs, organochlorine pesticides, flame retardants, metals) pose a potential threat to wildlife in some locations. Pharmaceuticals, personal care products, and endocrine disrupting compounds have been detected in water and fish tissue, yet knowledge of effects on wildlife is limited. This is the first study to examine bioaccumulation of pharmaceuticals and their fate in the water-fish-osprey food chain.
The Challenge: Polybrominated diphenyl ether flame retardants (PBDEs) are contaminants that bioaccumulate and biomagnify in aquatic and terrestrial food webs. Unlike many contemporary pollutants, these flame retardants have increased in the environment over the past 30 years. Studies in Chesapeake and Delaware Bays have documented concentrations of nearly 1 μg/g wet weight of PBDEs in osprey eggs, and even greater levels in peregrine falcon eggs. Limited information is available on the toxicity thresholds of these compounds and new organophosphate flame retardants in wildlife.
Biomarker responses of Peromyscus leucopus exposed to lead and cadmium in the Southeast Missouri Lead Mining District
Biomarker responses and histopathological lesions have been documented in laboratory mammals exposed to elevated concentrations of lead and cadmium. The exposure of white-footed mice (Peromyscus leucopus) to these metals and the potential associated toxic effects were examined at three contaminated sites in the Southeast Missouri Lead Mining...Beyer, W. Nelson; Casteel, Stan W.; Friedrichs, Kristen R.; Gramlich, Eric; Houseright, Ruth A.; Nichols, John W.; Karouna-Renier, Natalie; Kim, Dae Young; Rangen, Kathleen; Rattner, Barnett A.; Schultz, Sandra
Effects on circulating steroid hormones and gene expression along the hypothalamus–pituitary–gonadal axis in adult Japanese quail exposed to 17β-trenbolone across multiple generations
We investigated the effects of the androgenic growth promoter 17β-trenbolone (17βTB) on adult Japanese quail (Coturnix japonica) exposed across three generations. The F0 generation was exposed after sexual maturity to 0, 1, 5, 10, 20, and 40 ppm through feed. The F1 generation was exposed in ovo by maternal transfer and through feed at the same...Karouna-Renier, Natalie K.; Chen, Yu; Henry, Paula F.; Maddox, Catherine M.; Sprague, Dan
Current limitations and recommendations to improve testing for the environmental assessment of endocrine active substances
In the present study, existing regulatory frameworks and test systems for assessing potential endocrine active chemicals are described, and associated challenges are discussed, along with proposed approaches to address these challenges. Regulatory frameworks vary somewhat across geographies, but all basically evaluate whether a chemical possesses...Coady, Katherine K.; Biever, Ronald C.; Denslow, Nancy D.; Gross, Melanie; Guiney, Patrick D.; Holbech, Henrik; Karouna-Renier, Natalie K.; Katsiadaki, Ioanna; Krueger, Hank; Levine, Steven L.; Maack, Gerd; Williams, Mike; Wolf, Jeffrey C.; Ankley, Gerald T.
Recommended approaches to the scientific evaluation of ecotoxicological hazards and risks of endocrine-active substances
A SETAC Pellston Workshop® “Environmental Hazard and Risk Assessment Approaches for Endocrine-Active Substances (EHRA)” was held in February 2016 in Pensacola, Florida, USA. The primary objective of the workshop was to provide advice, based on current scientific understanding, to regulators and policy makers; the aim being to make considered...Matthiessen, Peter; Ankley, Gerald T.; Biever, Ronald C.; Bjerregaard, Poul; Borgert, Christopher; Brugger, Kristin; Blankinship, Amy; Chambers, Janice; Coady, Katherine K.; Constantine, Lisa; Dang, Zhichao; Denslow, Nancy D.; Dreier, David; Dungey, Steve; Gray, L. Earl; Gross, Melanie; Guiney, Patrick D.; Hecker, Markus; Holbech, Henrik; Iguchi, Taisen; Kadlec, Sarah; Karouna-Renier, Natalie K.; Katsiadaki, Ioanna; Kawashima, Yukio; Kloas, Werner; Krueger, Henry; Kumar, Anu; Lagadic, Laurent; Leopold, Annegaaike; Levine, Steven L.; Maack, Gerd; Marty, Sue; Meador, James P.; Mihaich, Ellen; Odum, Jenny; Ortego, Lisa; Parrott, Joanne L.; Pickford, Daniel; Roberts, Mike; Schaefers, Christoph; Schwarz, Tamar; Solomon, Keith; Verslycke, Tim; Weltje, Lennart; Wheeler, James R.; Williams, Mike; Wolf, Jeffery C.; Yamazaki, Kunihiko
Chesapeake Bay fish–osprey (Pandion haliaetus) food chain: Evaluation of contaminant exposure and genetic damage
From 2011 to 2013, a large-scale ecotoxicological study was conducted in several Chesapeake Bay (USA) tributaries (Susquehanna River and flats, the Back, Baltimore Harbor/Patapsco Rivers, Anacostia/ middle Potomac, Elizabeth and James Rivers) and Poplar Island as a mid-Bay reference site. Osprey (Pandion haliaetus) diet and the transfer of...Lazarus, Rebecca S.; Rattner, Barnett A.; McGowan, Peter C.; Hale, Robert C.; Karouna-Reiner, Natalie K.; Erickson, Richard A.; Ottinger, Mary Ann
Decadal re-evaluation of contaminant exposure and productivity of ospreys (Pandion haliaetus) nesting in Chesapeake Bay Regions of Concern
The last large-scale ecotoxicological study of ospreys (Pandion haliaetus) in Chesapeake Bay was conducted in 2000-2001 and focused on U.S. EPA-designated Regions of Concern (ROCs; Baltimore Harbor/Patapsco, Anacostia/middle Potomac, and Elizabeth Rivers). In 2011-2012, ROCs were re-evaluated to determine spatial and temporal trends in...Lazarus, Rebecca S.; Rattner, Barnett A.; McGowan, Peter C.; Hale, Robert C.; Schultz, Sandra; Karouna-Renier, Natalie K.; Ottinger, Mary Ann
Chromosomal damage and EROD induction in tree swallows (Tachycineta bicolor) along the Upper Mississippi River, Minnesota, USA
The health of tree swallows, Tachycineta bicolor, on the Upper Mississippi River (UMR) was assessed in 2010 and 2011 using biomarkers at six sites downriver of Minneapolis/St. Paul, MN metropolitan area, a tributary into the UMR, and a nearby lake. Chromosomal damage was evaluated in nestling blood by measuring the coefficient of...Emilie Bigorgne; Custer, Thomas W.; Dummer, Paul; Erickson, Richard A.; Karouna-Renier, Natalie K.; Schultz, Sandra; Custer, Christine M.; Thogmartin, Wayne E.; Cole W. Matson
Investigating endocrine and physiological parameters of captive American kestrels exposed by diet to selected organophosphate flame retardants
Organophosphate triesters are high production volume additive flame retardants (OPFRs) and plasticizers. Shown to accumulate in abiotic and biotic environmental compartments, little is known about the risks they pose. Captive adult male American kestrels (Falco sparverius) were fed the same dose (22 ng OPFR/g kestrel/d) daily (21 d) of tris(2-...Fernie, KJ; Palace, V; Peters, L.; Basu, Niladri; Letcher, R.J.; Karouna-Renier, Natalie K.; Schultz, Sandra; Lazarus, Rebecca S.; Rattner, Barnett A.
Changes in thyroid parameters of hatchling American kestrels (Falco sparverius) following embryonic exposure to technical short chain chlorinated paraffins (SCCPs; C10-13, 55.5% CL)
Chlorinated paraffins (CPs) are complex mixtures of polychlorinated n-alkanes categorized according to their carbon chain length: short chain (SCCPs, C10 – C13), medium (C14 - C17), and long chain (C>17), chlorinated paraffins. SCCPs are primarily used in metalworking applications, as flame retardants, and in paints, adhesives, sealants,...Fernie, Kimberly J; Henry, Paula F.; Letcher, Robert J; Palace, Vince; Peters, Lisa; Rattner, Barnett A.; Sverko, Edward; Karouna-Renier, Natalie K.
Assessment of mitochondrial DNA damage in little brown bats (Myotis lucifugus) collected near a mercury-contaminated river
Historical discharges of Hg into the South River near the town of Waynesboro, VA, USA, have resulted in persistently elevated Hg concentrations in sediment, surface water, ground water, soil, and wildlife downstream of the discharge site. In the present study, we examined mercury (Hg) levels in in little brown bats (Myotis lucifugus) from this...Karouna-Renier, Natalie K.; White, Carl; Perkins, Christopher R.; Schmerfeld, John J.; Yates, David
Comparative embryotoxicity of a pentabrominated diphenyl ether mixture to common terns (Sterna hirundo) and American kestrels (Falco sparverius)
Concentrations of polybrominated diphenyl ethers (PBDEs) in Forster’s tern (Sterna forsteri) eggs from San Francisco Bay have been reported to range up to 63 μg g−1 lipid weight. This value exceeds the lowest-observed-adverse-effect level (1.8 μg g−1 egg wet weight; ∼32 μg−1 lipid weight) reported in an embryotoxicity study with American kestrels...Rattner, Barnett A.; Lazarus, Rebecca S.; Heinz, Gary H.; Karouna-Reiner, Natalie K.; Schultz, Sandra L.; Hale, Robert C.
Gene expression, glutathione status and indicators of hepatic oxidative stress in laughing gull (Larus atricilla) hatchlings exposed to methylmercury
Despite extensive studies of methylmercury (MeHg) toxicity in birds, molecular effects on birds are poorly characterized. To improve our understanding of toxicity pathways and identify novel indicators of avian exposure to Hg, the authors investigated genomic changes, glutathione status, and oxidative status indicators in liver from laughing gull...Jenko, Kathryn; Karouna-Renier, Natalie K.; Hoffman, David J.