Luke R Iwanowicz, Ph.D. (Former Employee)
Science and Products
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Description of two new gill myxozoans from smallmouth (Micropterus dolomieu) and largemouth bass (Micropterus salmoides)
Two previously undescribed species of myxozoan parasites were observed in the gills of bass inhabiting the Potomac and James River basins. They are described using morphological characteristics and small-subunit (SSU) rDNA gene sequences. Both were taxonomically identified as new species of Myxobolus; Myxobolus branchiarum n. sp. was found exclusively in smallmouth bass, and Myxobolus micropterii
Authors
Heather L. Walsh, Luke R. Iwanowicz, Gavin W. Glenney, Deborah D. Iwanowicz, Vicki Blazer
Reproductive endocrine disruption in smallmouth bass (Micropterus dolomieu) in the Potomac River basin: spatial and temporal comparisons of biological effects
A high prevalence of intersex or testicular oocytes (TO) in male smallmouth bass within the Potomac River drainage has raised concerns as to the health of the river. Studies were conducted to document biomarker responses both temporally and spatially to better understand the influence of normal physiological cycles, as well as water quality and land-use influences. Smallmouth bass were collected o
Authors
Vicki Blazer, Luke R. Iwanowicz, Holly Henderson, Patricia M. Mazik, Jill A. Jenkins, David A. Alvarez, John A. Young
An overview of estrogen-associated endocrine disruption in fishes: Evidence of effects on reproductive and immune physiology
Simply and perhaps intuitively defined, endocrine disruption is the abnormal modulation of normal hormonal physiology by exogenous chemicals. In fish, endocrine disruption of the reproductive system has been observed worldwide in numerous species and is known to affect both males and females. Observations of biologically relevant endocrine disruption most commonly occurs near waste water treatment
Authors
Luke R. Iwanowicz, Vicki S. Blazer
Steroid determination in fish plasma using capillary electrophoresis
A capillary separation method that incorporates pH-mediated stacking is employed for the simultaneous determination of circulating steroid hormones in plasma from Perca flavescens (yellow perch) collected from natural aquatic environments. The method can be applied to separate eight steroid standards: progesterone, 17α,20β-dihydroxypregn-4-en-3-one, 17α-hydroxyprogesterone, testosterone, estrone,
Authors
L. Bykova, S. A. Archer-Hartmann, L.A. Holland, Luke R. Iwanowicz, Vicki S. Blazer
Mortality of centrarchid fishes in the Potomac drainage: Survey results and overview of potential contributing factors
Skin lesions and spring mortality events of smallmouth bass Micropterus dolomieu and selected other species were first noted in the South Branch of the Potomac River in 2002. Since that year morbidity and mortality have also been observed in the Shenandoah and Monocacy rivers. Despite much research, no single pathogen, parasite, or chemical cause for the lesions and mortality has been identified.
Authors
Vicki Blazer, Luke R. Iwanowicz, Clifford E. Starliper, Steven D. Zaugg, Mark R. Burkhardt, P. Barbash, J.D. Hedrick, S.J. Reeser, J.E. Mullican, J. Kelble
Author's response to "If poultry's to blame, Where's the proof?"
No abstract available.
Authors
J.L. Ripley, C. Foran, Luke R. Iwanowicz, Vicki S. Blazer
Reproductive health of bass in the potomac, USA, drainage: Part 2. Seasonal occurrence of persistent and emerging organic contaminants
The seasonal occurrence of organic contaminants, many of which are potential endocrine disruptors, entering the Potomac River, USA, watershed was investigated using a two-pronged approach during the fall of 2005 and spring of 2006. Passive samplers (semipermeable membrane device and polar organic chemical integrative sampler [POCIS]) were deployed in tandem at sites above and below wastewater trea
Authors
D.A. Alvarez, W.L. Cranor, S.D. Perkins, V.L. Schroeder, L. R. Iwanowicz, R.C. Clark, C.P. Guy, A.E. Pinkney, V. S. Blazer, J.E. Mullican
Reproductive health of bass in the potomac, USA, drainage: Part 1. exploring the effects of proximity to wastewater treatment plant discharge
Intersex (specifically, testicular oocytes) has been observed in male smallmouth bass (SMB; Micropterus dolomieu) and other centrarchids in the South Branch of the Potomac River, USA, and forks of the Shenandoah River, USA, during the past five years. This condition often is associated with exposure to estrogenic endocrine‐disrupting chemicals in some fish species, but such chemicals and their sou
Authors
L. R. Iwanowicz, V. S. Blazer, C.P. Guy, A.E. Pinkney, J.E. Mullcan, D.A. Alvarezw
Identification of centrarchid hepcidins and evidence that 17β-estradiol disrupts constitutive expression of hepcidin-1 and inducible expression of hepcidin-2 in largemouth bass (Micropterus salmoides)
Hepcidin is a highly conserved antimicrobial peptide and iron-regulatory hormone. Here, we identify two hepcidin genes (hep-1 and hep-2) in largemouth bass (Micropterus salmoides) and smallmouth bass (Micropterus dolomieu). Hepcidin-1 contains a putative ATCUN metal-binding site in the amino-terminus that is missing in hepcidin-2, suggesting that hepcidin-1 may function as an iron-regulatory hormo
Authors
L.S. Robertson, L. R. Iwanowicz, J.M. Marranca
Aroclor 1248 exposure leads to immunomodulation, decreased disease resistance and endocrine disruption in the brown bullhead, Ameiurus nebulosus
The brown bullhead Ameiurus nebulosus is a species of the family Ictaluridae commonly used as a sentinel of environmental contamination. While these fish have been utilized for this purpose in areas contaminated with polychlorinated biphenyls (PCBs), few controlled, laboratory-based studies have been designed to document the effects of PCB mixtures in this species. Here, brown bullhead were expose
Authors
L. R. Iwanowicz, V. S. Blazer, S. D. McCormick, P.A. Van Veld, C. A. Ottinger
Estrogens, estrogen receptors and their role as immunoregulators in fish
No abstract available.
Authors
Luke R. Iwanowicz, Christopher A. Ottinger
Morphology and 18S rDNA of Henneguya gurlei (Myxosporea) from Ameiurus nebulosus (Siluriformes) in North Carolina
Henneguya gurlei was isolated from Ameiurus nebulosus captured in North Carolina and redescribed using critical morphological features and 18S small-subunit ribosomal RNA (SSU rDNA) gene sequence. Plasmodia are white, spherical, or subspherical, occur in clusters, measure up to 1.8 mm in length, and are located on the dorsal, pectoral, and anal fins. Histologically, plasmodia are located in the de
Authors
L. R. Iwanowicz, D.D. Iwanowicz, L.M. Pote, V. S. Blazer, W. B. Schill
Non-USGS Publications**
Iwanowicz, L., L Brown, B Eltz, F Juanes and J Murt (2004) Book Review. In a Perfect Ocean: The state of fisheries and ecosystems in the North Atlantic Ocean. Reviews in Fish Biology and Fisheries.14: 149-151.
McIntire, M., L R Iwanowicz and A E Goodwin (2003) Molecular, physical and clinical evidence that Golden Shiner Virus (GSV) and Grass Carp Reovirus (GCRV) are variants of the same virus. Journal of Aquatic Animal Health. 15: 257-263.
Iwanowicz, L.R. and A E Goodwin (2002) Characterization of a new bacilliform fathead minnow rhabdovirus that produces syncytia in tissue culture. Archives of Virology 147: 889 – 916.
Iwanowicz, L.R. A E Goodwin and J Harshbarger (2001) Embryonal rhabdomyosarcoma of the giant gourami, Colisa fasciata (Bloch & Schneider). Journal of Fish Diseases 24:177-179
Iwanowicz, L.R. A E Goodwin and N Heil (2000) A small RNA virus isolated from apparently healthy wild sandbar shiners, Notropis scepticus. Journal of Fish Diseases 23: 349-352.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 13
Filter Total Items: 22
No Result Found
Filter Total Items: 103
Description of two new gill myxozoans from smallmouth (Micropterus dolomieu) and largemouth bass (Micropterus salmoides)
Two previously undescribed species of myxozoan parasites were observed in the gills of bass inhabiting the Potomac and James River basins. They are described using morphological characteristics and small-subunit (SSU) rDNA gene sequences. Both were taxonomically identified as new species of Myxobolus; Myxobolus branchiarum n. sp. was found exclusively in smallmouth bass, and Myxobolus micropterii
Authors
Heather L. Walsh, Luke R. Iwanowicz, Gavin W. Glenney, Deborah D. Iwanowicz, Vicki Blazer
Reproductive endocrine disruption in smallmouth bass (Micropterus dolomieu) in the Potomac River basin: spatial and temporal comparisons of biological effects
A high prevalence of intersex or testicular oocytes (TO) in male smallmouth bass within the Potomac River drainage has raised concerns as to the health of the river. Studies were conducted to document biomarker responses both temporally and spatially to better understand the influence of normal physiological cycles, as well as water quality and land-use influences. Smallmouth bass were collected o
Authors
Vicki Blazer, Luke R. Iwanowicz, Holly Henderson, Patricia M. Mazik, Jill A. Jenkins, David A. Alvarez, John A. Young
An overview of estrogen-associated endocrine disruption in fishes: Evidence of effects on reproductive and immune physiology
Simply and perhaps intuitively defined, endocrine disruption is the abnormal modulation of normal hormonal physiology by exogenous chemicals. In fish, endocrine disruption of the reproductive system has been observed worldwide in numerous species and is known to affect both males and females. Observations of biologically relevant endocrine disruption most commonly occurs near waste water treatment
Authors
Luke R. Iwanowicz, Vicki S. Blazer
Steroid determination in fish plasma using capillary electrophoresis
A capillary separation method that incorporates pH-mediated stacking is employed for the simultaneous determination of circulating steroid hormones in plasma from Perca flavescens (yellow perch) collected from natural aquatic environments. The method can be applied to separate eight steroid standards: progesterone, 17α,20β-dihydroxypregn-4-en-3-one, 17α-hydroxyprogesterone, testosterone, estrone,
Authors
L. Bykova, S. A. Archer-Hartmann, L.A. Holland, Luke R. Iwanowicz, Vicki S. Blazer
Mortality of centrarchid fishes in the Potomac drainage: Survey results and overview of potential contributing factors
Skin lesions and spring mortality events of smallmouth bass Micropterus dolomieu and selected other species were first noted in the South Branch of the Potomac River in 2002. Since that year morbidity and mortality have also been observed in the Shenandoah and Monocacy rivers. Despite much research, no single pathogen, parasite, or chemical cause for the lesions and mortality has been identified.
Authors
Vicki Blazer, Luke R. Iwanowicz, Clifford E. Starliper, Steven D. Zaugg, Mark R. Burkhardt, P. Barbash, J.D. Hedrick, S.J. Reeser, J.E. Mullican, J. Kelble
Author's response to "If poultry's to blame, Where's the proof?"
No abstract available.
Authors
J.L. Ripley, C. Foran, Luke R. Iwanowicz, Vicki S. Blazer
Reproductive health of bass in the potomac, USA, drainage: Part 2. Seasonal occurrence of persistent and emerging organic contaminants
The seasonal occurrence of organic contaminants, many of which are potential endocrine disruptors, entering the Potomac River, USA, watershed was investigated using a two-pronged approach during the fall of 2005 and spring of 2006. Passive samplers (semipermeable membrane device and polar organic chemical integrative sampler [POCIS]) were deployed in tandem at sites above and below wastewater trea
Authors
D.A. Alvarez, W.L. Cranor, S.D. Perkins, V.L. Schroeder, L. R. Iwanowicz, R.C. Clark, C.P. Guy, A.E. Pinkney, V. S. Blazer, J.E. Mullican
Reproductive health of bass in the potomac, USA, drainage: Part 1. exploring the effects of proximity to wastewater treatment plant discharge
Intersex (specifically, testicular oocytes) has been observed in male smallmouth bass (SMB; Micropterus dolomieu) and other centrarchids in the South Branch of the Potomac River, USA, and forks of the Shenandoah River, USA, during the past five years. This condition often is associated with exposure to estrogenic endocrine‐disrupting chemicals in some fish species, but such chemicals and their sou
Authors
L. R. Iwanowicz, V. S. Blazer, C.P. Guy, A.E. Pinkney, J.E. Mullcan, D.A. Alvarezw
Identification of centrarchid hepcidins and evidence that 17β-estradiol disrupts constitutive expression of hepcidin-1 and inducible expression of hepcidin-2 in largemouth bass (Micropterus salmoides)
Hepcidin is a highly conserved antimicrobial peptide and iron-regulatory hormone. Here, we identify two hepcidin genes (hep-1 and hep-2) in largemouth bass (Micropterus salmoides) and smallmouth bass (Micropterus dolomieu). Hepcidin-1 contains a putative ATCUN metal-binding site in the amino-terminus that is missing in hepcidin-2, suggesting that hepcidin-1 may function as an iron-regulatory hormo
Authors
L.S. Robertson, L. R. Iwanowicz, J.M. Marranca
Aroclor 1248 exposure leads to immunomodulation, decreased disease resistance and endocrine disruption in the brown bullhead, Ameiurus nebulosus
The brown bullhead Ameiurus nebulosus is a species of the family Ictaluridae commonly used as a sentinel of environmental contamination. While these fish have been utilized for this purpose in areas contaminated with polychlorinated biphenyls (PCBs), few controlled, laboratory-based studies have been designed to document the effects of PCB mixtures in this species. Here, brown bullhead were expose
Authors
L. R. Iwanowicz, V. S. Blazer, S. D. McCormick, P.A. Van Veld, C. A. Ottinger
Estrogens, estrogen receptors and their role as immunoregulators in fish
No abstract available.
Authors
Luke R. Iwanowicz, Christopher A. Ottinger
Morphology and 18S rDNA of Henneguya gurlei (Myxosporea) from Ameiurus nebulosus (Siluriformes) in North Carolina
Henneguya gurlei was isolated from Ameiurus nebulosus captured in North Carolina and redescribed using critical morphological features and 18S small-subunit ribosomal RNA (SSU rDNA) gene sequence. Plasmodia are white, spherical, or subspherical, occur in clusters, measure up to 1.8 mm in length, and are located on the dorsal, pectoral, and anal fins. Histologically, plasmodia are located in the de
Authors
L. R. Iwanowicz, D.D. Iwanowicz, L.M. Pote, V. S. Blazer, W. B. Schill
Non-USGS Publications**
Iwanowicz, L., L Brown, B Eltz, F Juanes and J Murt (2004) Book Review. In a Perfect Ocean: The state of fisheries and ecosystems in the North Atlantic Ocean. Reviews in Fish Biology and Fisheries.14: 149-151.
McIntire, M., L R Iwanowicz and A E Goodwin (2003) Molecular, physical and clinical evidence that Golden Shiner Virus (GSV) and Grass Carp Reovirus (GCRV) are variants of the same virus. Journal of Aquatic Animal Health. 15: 257-263.
Iwanowicz, L.R. and A E Goodwin (2002) Characterization of a new bacilliform fathead minnow rhabdovirus that produces syncytia in tissue culture. Archives of Virology 147: 889 – 916.
Iwanowicz, L.R. A E Goodwin and J Harshbarger (2001) Embryonal rhabdomyosarcoma of the giant gourami, Colisa fasciata (Bloch & Schneider). Journal of Fish Diseases 24:177-179
Iwanowicz, L.R. A E Goodwin and N Heil (2000) A small RNA virus isolated from apparently healthy wild sandbar shiners, Notropis scepticus. Journal of Fish Diseases 23: 349-352.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government