USGS Professional Pages
In Review Miles, A.K., L. Bowen, B. Ballachey, J.L. Bodkin, M. Murray, R.A. Keister, J.L. Stott. Gene Transcription and Evidence of Physiological Pathology in Sea Otters (Enhydra lutris) Two Decades Post Exxon Valdez. In Review at Marine Ecology Progress Series.
2012 Bowen, L., A.K. Miles, M. Murray, M. Haulena, J. Tuttle, W. Van Bonn, L. Adams, J.L. Bodkin, B. Ballachey, J.Estes, M. T. Tinker, R. Keister, J.L. Stott. 2012. Gene Transcription in Sea Otters (Enhydra lutris); Development of a Diagnostic Tool for Sea Otter and Ecosystem Health. Molecular Ecology Resources 12:67-74.
2011 Bowen, L., J.D. Kiernan, K. Eder, I. Werner, C.M. Leuterngger, M.A. Adkison, R.P. Hedrick, M.L. Johnson. Euthanization Methods Influence Cytokine mRNA Expression Levels in Steelhead Trout (Oncorhynchus mykiss). Journal of Fish Biology. In press.
2010 Sitt, T., L. Bowen, M.T. Blanchard, L.J. Gershwin, B.A. Byren, C. Dold, J. McBain, and J.L. Stott. Cellular Immune Responses in Cetaceans Immunized with a Porcine Erysipelas Vaccine. Veterinary Immunology and Immunopathology 2010 137: 181-189.
2008 Sitt, T., L. Bowen, M. T. Blanchard, B. R. Smith, L. J. Gershwin, B. A. Byrne, J. L. Stott. Quantitation of leukocyte gene expression in cetaceans. Developmental and Comparative Immunology 2008, 32:1253-1259.
2007 Bowen, L., F. Riva, C. Mohr, B. Aldridge, J. Schwartz, A.K.Miles, and J.L. Stott. Differential gene expression induced by exposure of captive mink to fuel oil: a model for the sea otter. EcoHealth, 2007, 4 (3):298-309.
2007 Chen, C., D.P. King, M.T. Blanchard, M.R. Hall, B.M. Aldridge, L. Bowen, J.L. Stott. Identification of the Etiologic Agent of Epizootic Bovine Abortion in Field-Collected Ornithodoros coriaceus Koch. Vet Microbiol. 2007 Mar 10;120:320-7
2006 DeCarlo, C, J.C. Alderson, L. Bowen, J. Rutllant, B.M. Aldridge. Characterization of the Immunomodulatory effect of a commercial extender on semen-induced imflammatory response in equine uterine lumen immune cells. Journal of Reproductive Immunology. 2006 71: 158.
2006 Bowen, L., B. Aldridge, A.K. Miles, and J.L. Stott. Partial characterization of MHC genes in geographically disparate populations of sea otters (Enhydra lutris). Tissue Antigens. 2006 May;67(5):402-8.
2006 Aldridge, B., L. Bowen, B. Smith, F. Gulland, G. Antonellis, and J. Stott. Paucity of class I MHC gene variation in the endangered Hawaiian monk seal population. Immunogenetics. 2006 Apr;58 (2-3):203-15.
2006 Bowen, L., B. Aldridge, K. Beckmen, T. Gelatt, L. Rea, K. Burek, K. Pitcher, and J.L. Stott. Differential expression of immune response genes in Steller sea lions: an indicator of ecosystem health? EcoHealth. 2006 3:109-113.
2006 Bowen, L. and M. Johnson. 2006. Physiologic and behavioral effects of zinc and temperature on Coho salmon (Oncorhynchus kisutch). Hydrobiologia 559: 161-168.
2006 Bowen, L., B. Aldridge, C. Godinez, A. Zavala, L. Lowenstine, S. Melin, R. DeLong, J. Stott, and M. Johnson. 2006. MHC gene configuration variation in geographically disparate populations of California sea lion (Zalophus californianus): pathogen pressure or breeding biology? Molecular Ecology 15 (2), 529-533.
Bowen, L., B. Aldridge, R. DeLong, F. Gulland, L. Lowenstine, J. Stott, and M. Johnson. 2005. An immunogenetic basis for the urogenital cancer epidemic of California sea lions (Zalophus californianus). Immunogenetics 56: 846-848.
2004 Bowen, L., B.M. Aldridge, J.L. Stott, F. Gulland, W. Van Bonn, R. DeLong, L. Lowenstine, and M.L. Johnson. 2004. Multiple and variable DRB lineages in the California sea lion (Zalophus californianus). Immunogenetics 56:12-27.
2002 Bowen, L., B.M. Aldridge, J.L. Stott, F. Gulland, J. Woo, W. Van Bonn, R. DeLong, L. Lowenstine, and M.L. Johnson. 2002. Molecular characterization of expressed DQA and DQB genes in the California sea lion (Zalophus californianus). Immunogenetics 54:332-347.
2002 Johnson, M. L., G. Pasternack, J. Florsheim, I. Werner, T. B. Smith, L. Bowen, M. Turner, J. Viers, J. Steinmetz, J. Constantine, E. Huber, and O. Jorda. 2002. The impact of abiotic and biotic stressors on salmonids in the Navarro River watershed, Vols I-III. Report CTSW-RT-02-040 to the Division of Environmental Analysis, California Department of Transportation, Interagency Agreement Nos 43A0014 and 43A0073.
2001 Van Vuren, D.H., M.L. Johnson, and L. Bowen. 2001. Impacts of feral livestock on island watersheds. Pacific Science. Vol. 55:285-290.
2001 Crooks, K. R., C. Scott, L. Angeloni, L. Bowen, R. B. Kimsey, and D. H. Van Vuren. 2001. Ectoparasites of the island fox on Santa Cruz Island. Journal of Wildlife Diseases. 37:189-193.
2000 Crooks, K., D.Van Vuren, C. Scott, and L. Bowen. 2000. Hematology and serum chemistry of the island
fox on Santa Cruz Island. Journal of Wildlife Disease. Vol. 36: 397-404.
1999 Bowen, L., and D. Van Vuren. 1999. Density, reproduction, and group size in feral sheep on Santa Cruz Island, California. Mammalia. Vol. 63: 21-28.
1999 Van Vuren, D., and L. Bowen. 1999. Reduced defenses in insular endemic plants: an evolutionary time frame. Conservation Biology. Vol. 13: 211.
1997 Bowen, L., and D. Van Vuren. 1997. Insular endemic plants lack defenses against herbivory. Conservation Biology. Vol. 11: 1249-1254.
1997 Bowen, L., and D. Van Vuren. 1997. Island plants let down their defenses. Plants on Santa Cruz Island off California have significantly fewer defenses against animal grazers than do their mainland counterparts. Science News November 29, 1997.
My USGS Science Strategy AreasUnderstanding Ecosystems & Predicting Ecosystems Change
The Role of Environment and Wildlife in Human Health
Individual and Ecosystem Health
My research examines the physiologic and metabolic effects of stressors on organisms and how subsequent vulnerabilities translate into population and ecosystem health. Stressors can be either physical (e.g., elevated water temperature), chemical (pesticides, petroleum hydrocarbons), or biological (pathogens). The stressor/response paradigm enables me to extend my research into marine and terrestrial ecosystems, and organisms from marine mammals to desert tortoises. My research program focuses on the interactions among toxicology, disease ecology, immunology, and ecosystem health. My long-term goal is to better understand the effects of anthropogenic and natural stressors on individuals and how those stressors are reflected in an individual organism’s fitness (survival and reproduction), the population level effects of differential survival and reproduction of individuals, and the ecosystem level effects of population change.
I focus on the application of the next generation of molecular research tools to pursue specific questions and hypotheses related to marine and terrestrial ecosystem health. In order to identify physiologic responses at the organismal level, and translate these into population and ecosystem level effects, it is necessary to examine biomarkers of effect. Recent advances in genetic technology have provided us with powerful tools to investigate mechanisms of insult at the molecular level. The advantage of using gene expression assays in aquatic toxicology is the ability to measure the chronic physiologic responses of an individual to the specific insult, independent of the presence of the original toxin or its metabolites. Stressor-specific gene-expression patterns can be identified either on free-ranging animals opportunistically (such as animals caught in a chemical spill) or under experimental conditions (lab or field) using animal models.
Gene expression is the process by which messenger RNA (mRNA), and eventually a functional protein, is synthesized from the DNA template of a particular gene. Genomic analysis of mRNA can therefore be used as a measure of gene expression. As a result of its keystone function, analysis of mRNA can provide information about the functional genetic potential of an organism. mRNA levels may or may not closely approximate functional protein levels, but specific changes in mRNA have been identified following heat shock, drug treatment, metabolic perturbations, and disease. The utility of this methodology relies on the hypothesis that sublethal pathology in any organism is accompanied by changes in gene expression.
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