TY - THES TI - Effects of Natural Irradiance Fluctuations on the Photosynthetic Responses of Gymnodinium Breve (Karenia Brevis) and Thalassiosira Pseudonana and Hydrographic Structure Associated with Persistent Gymnodinium Breve (Karenia Brevis) Subsurface Accumulations with Implications for Red Tide Patch Information AU - Reed, R.E. DA - 2001/// PY - 2001/// M3 - Ph.D. Dissertation PB - North Carolina State University ER - TY - JOUR TI - Field ecology of toxic Pfiesteria complex species and a conservative analysis of their role in estuarine fish kills. AU - Glasgow, H B AU - Burkholder, J M AU - Mallin, M A AU - Deamer-Melia, N J AU - Reed, R E T2 - Environmental Health Perspectives AB - Within the past decade, toxic Pfiesteria outbreaks have been documented in poorly flushed, eutrophic areas of the largest and second largest estuaries on the U.S. mainland. Here we summarize a decadal field effort in fish kill assessment, encompassing kills related to Pfiesteria (49 major kills in North Carolina estuaries since 1991 and 4 in Maryland estuaries in 1997) and to other factors such as low oxygen stress (79 major fish kills in North Carolina estuaries). The laboratory and field data considered in developing our protocols are described, including toxic Pfiesteria behavior, environmental conditions conducive to toxic Pfiesteria activity, and impacts of toxic clonal Pfiesteria on fish health. We outline the steps of the standardized fish bioassay procedure that has been used since 1991 to diagnose whether actively toxic Pfiesteria was present during estuarine fish kills. Detailed data are given for a 1998 toxic Pfiesteria outbreak in the Neuse Estuary in North Carolina to illustrate of the full suite of diagnostic steps completed. We demonstrate that our conservative approach in implicating toxic Pfiesteria involvement in fish kills has biased in favor of causes other than Pfiesteria. Data are summarized from experiments that have shown stimulation of toxic Pfiesteria strains by nutrient (N, P) enrichment, supporting field observations of highest abundance of toxic strains in eutrophic estuaries. On the basis of a decade of research on toxic Pfiesteria, we present a conceptual model of the seasonal dynamics of toxic strains as affected by changing food resources and weather patterns. We also recommend protocols and research approaches that will strengthen the science of fish kill assessment related to Pfiesteria and/or other causative factors. DA - 2001/10// PY - 2001/10// DO - 10.1289/ehp.01109s5715 VL - 109 IS - suppl 5 SP - 715-730 J2 - Environmental Health Perspectives LA - en OP - SN - 0091-6765 1552-9924 UR - http://dx.doi.org/10.1289/ehp.01109s5715 DB - Crossref ER - TY - JOUR TI - Use of molecular probes to assess geographic distribution of Pfiesteria species AU - Rublee, PA AU - Kempton, JW AU - Schaefer, EF AU - Allen, C AU - Harris, J AU - Oldach, DW AU - Bowers, H AU - Tengs, T AU - Burkholder, JM AU - Glasgow, HB T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/10// PY - 2001/10// DO - 10.2307/3454924 VL - 109 SP - 765-767 SN - 0091-6765 KW - molecular probes KW - PCR KW - Pfiesteria KW - toxic dinoflagellates ER - TY - JOUR TI - The standardized fish bioassay procedure for detecting and culturing actively toxic Pfiesteria, used by two reference laboratories for Atlantic and Gulf Coast states AU - Burkholder, JM AU - Marshall, HG AU - Glasgow, HB AU - Seaborn, DW AU - Deamer-Melia, NJ T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/10// PY - 2001/10// DO - 10.2307/3454922 VL - 109 SP - 745-756 SN - 1552-9924 KW - culture KW - dinoflagellates KW - functional type KW - standardized fish bioassay KW - toxic Pfiesteria complex ER - TY - JOUR TI - Microfluorimetric analysis of a purinergic receptor (P2X(7)) in GH(4)C(1) rat pituitary cells: Effects of a bioactive substance produced by Pfiesteria piscicida AU - Melo, AC AU - Moeller, PDR AU - Glasgow, H AU - Burkholder, JM AU - Ramsdell, JS T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/10// PY - 2001/10// DO - 10.2307/3454920 VL - 109 SP - 731-737 SN - 0091-6765 KW - GH(4)C(1) KW - Pfiesteria KW - purinergic receptors KW - P2X(7) KW - toxin ER - TY - JOUR TI - Field ecology of toxic Pfiesteria complex species and a conservative analysis of their role in estuarine fish kills AU - Glasgow, HB AU - Burkholder, JM AU - Mallin, MA AU - Deamer-Melia, NJ AU - Reed, RE T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/10// PY - 2001/10// DO - 10.2307/3454919 VL - 109 SP - 715-730 SN - 1552-9924 KW - dinoflagellates KW - dissolved oxygen KW - estuaries KW - fish kills KW - nutrients KW - toxic Pfiesteria complex ER - TY - JOUR TI - Current progress in isolation and characterization of toxins isolated from Pfiesteria piscicida AU - Moeller, PDR AU - Morton, SL AU - Mitchell, BA AU - Sivertsen, SK AU - Fairey, ER AU - Mikulski, TM AU - Glasgow, H AU - Deamer-Melia, NJ AU - Burkholder, JM AU - Ramsdell, JS T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/10// PY - 2001/10// DO - 10.2307/3454921 VL - 109 SP - 739-743 SN - 0091-6765 KW - assay KW - chromatography KW - GH(4)C(1) KW - Pfiesteria piscicida KW - toxin bioassay ER - TY - JOUR TI - Specificity of cognitive impairment from Pfiesteria piscicida exposure in rats - Attention and visual function versus behavioral plasticity AU - Rezvani, AH AU - Bushnell, PJ AU - Burkholder, JM AU - Glasgow, HB AU - Levin, ED T2 - NEUROTOXICOLOGY AND TERATOLOGY AB - Pfiesteria piscicida is a toxic dinoflagellate that has caused massive fish kills in estuaries along the East Coast of the United States, and exposure of humans to toxic Pfiesteria has been associated with cognitive impairment. A visual signal detection task was used to determine the possible importance of attentional and visual processes in Pfiesteria effects on cognitive function. Adult female rats were trained to perform the signal detection task. After training, the rats were injected subcutaneously with fish culture water containing toxic Pfiesteria (35,600 or 106,800 cells of Pfiesteria/kg of rat body weight) or with (control) fish culture water containing no Pfiesteria. Effects of toxic Pfiesteria on maintenance of signal detection behavior were assessed for 2 weeks after treatment. Then, the signal-response contingencies were reversed. After the discrimination was reestablished on the reversed levers, the rats received a second dose of toxic Pfiesteria. The rats were again tested for 2 weeks, after which a second reversal was imposed. Pfiesteria did not affect behavior in the signal detection task during 2 weeks of prereversal testing after either exposure. However, a significant Pfiesteria-induced deficit emerged when the signal-response contingencies were reversed. These findings suggest that Pfiesteria-induced deficits emerge during periods of behavioral transition and not during performance of previously learned tasks. DA - 2001/// PY - 2001/// DO - 10.1016/S0892-0362(01)00169-6 VL - 23 IS - 6 SP - 609-616 SN - 1872-9738 KW - toxic KW - dinoflagellates KW - Pfiesteria KW - learning KW - visual signal detection test KW - radial-ann maze KW - figure-8 maze ER - TY - JOUR TI - Chemosensory attraction of zoospores of the estuarine dinoflagellates, Pfiesteria piscicida and P-shumwayae, to finfish mucus and excreta AU - Cancellieri, PJ AU - Burkholder, JM AU - Deamer-Melia, NJ AU - Glasgow, HB T2 - JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY AB - Toxic strains of the estuarine dinoflagellates, Pfiesteria piscicida and P. shumwayae, can cause fish death and disease, whereas other estuarine ‘lookalike’ species such as cryptoperidiniopsoids have not been ichthyotoxic under ecologically relevant conditions. Chemosensory attraction of three functional types of these Pfiesteria spp. were separately evaluated for their attraction to fresh fish mucus and excreta. Clonal cultures of actively toxic (TOX-A, engaged in killing fish) and temporarily nontoxic (tested as toxic but without access to live fish for >1 week to 5 months (in most experiments, ≤3 months) as ‘short-duration’ TOX-B; and without access to live fish for ≥1.5 years as ‘long-duration’ TOX-B) functional types of P. piscicida and P. shumwayae were derived from the same clones whereas the non-inducible cultures (NON-IND, tested as incapable of toxic activity in the presence of fish), of necessity, were from different clonal isolates. NON-IND cultures previously had been grown on algal prey for 3–8 months, and had repeatedly been tested as incapable of causing fish distress, disease or death via toxic activity. Attraction to fish materials was based on the number of zoospores that entered microcapillary tubes containing sterile-filtered 15-ppt water (controls), vs. entry into tubes with sterile-filtered mucus and excreta (collected in 15-ppt water) that had been collected from live tilapia, bluegill, hybrid striped bass, and Atlantic menhaden (tested separately within 3 h of removal from live fish). TOX-A zoospores of both Pfiesteria species exhibited the strongest attraction to the fish mucus and excreta, with comparable response to the materials from all four test fish species. Short-duration TOX-B zoospores showed an intermediate response that apparently depended on the duration of mucus separation from the live fish: the shorter the separation period, the stronger the zoospore attraction to the fish materials. In contrast to TOX-A and short-duration TOX-B zoospores, NON-IND and long-duration TOX-B zoospores generally showed little or no response to the fish materials. Zoospores of the cryptoperidiniopsoid demonstrated a moderate attraction that did not appear to depend on the time of isolation from fish. TOX-A zoospores were also tested for attraction to sterile-filtered vs. non-filtered fish mucus (time separated from the live animal, 3–96 h). These zoospores, which initially had been actively attracted, were no longer attracted to the unfiltered fish materials after 48 h, whereas attraction to the sterile-filtered fish mucus and excreta persisted throughout the duration of the experiment. Thus, the attractant signal in the materials was degraded or effectively blocked by the bacterial community within hours of isolation from live fish. This study indicates the importance of functional type or toxicity status, and the importance of the history of exposure to live fish, in the behavioral ecology of Pfiesteria spp. Initial attraction to fish materials strongly depended on the functional type, and on the history of toxic activity. Non-inducible and long-duration TOX-B cultures of Pfiesteria spp., unlike actively toxic and short-duration TOX-B (potentially toxic) strains, initially were virtually unresponsive to fish mucus. DA - 2001/9/15/ PY - 2001/9/15/ DO - 10.1016/S0022-0981(01)00299-4 VL - 264 IS - 1 SP - 29-45 SN - 1879-1697 KW - chemosensory KW - functional type KW - estuary KW - fish mucus KW - non-inducible KW - toxic dinoflagellate KW - toxic Pfiesteria complex KW - cryptoperidiniopsoid ER - TY - JOUR TI - History of toxic Pfiesteria in North Carolina estuaries from 1991 to the present AU - Burkholder, JM AU - Glasgow, HB T2 - BIOSCIENCE DA - 2001/10// PY - 2001/10// DO - 10.1641/0006-3568(2001)051[0827:HOTPIN]2.0.CO;2 VL - 51 IS - 10 SP - 827-841 SN - 1525-3244 ER - TY - JOUR TI - Nitrate reductase activity in a submersed marine angiosperm: Controlling influences of environmental and physiological factors AU - Touchette, BW AU - Burkholder, J T2 - PLANT PHYSIOLOGY AND BIOCHEMISTRY AB - In plants, nitrate reductase (NR; EC 1.6.6.1) is considered to be a key enzyme in nitrate assimilation. Therefore, the activity of NR as influenced by major environmental factors may affect the survival of many aquatic nitrogen-limited plant species. In this study, the in vivo activity of NR following exposure to increased water-column nitrate was examined in a submersed marine angiosperm (eelgrass, Zostera marina L.). NR activity was primarily localized in new leaf tissue, and was related to light and/or soluble carbohydrate availability. Under extended periods of darkness (18 h), enzyme activity decreased by more than 60 %. Nevertheless, in vivo NR activity was induced during dark periods provided that water-column nitrate (≥ 8 μM NO3–) was available. Enzyme activities were lower in plants that were exposed to hypoxic conditions (< 3.5 mg O2·L–1 for 14 h), and/or elevated growth temperatures (3 to 4 °C above mean weekly temperatures). In contrast, exposure to the atmosphere for 90 min promoted a significant increase in in vivo NR activity. A temporal investigation (14 weeks in autumn) revealed that the intensity of in vivo NR response to water-column nitrate was directly correlated with the quantity of soluble carbohydrates within the leaf tissue. Many of the observed in vivo NR responses were likely related to carbohydrate availability. During periods where soluble carbohydrate availability was expected to be low, in vivo NR response to increased water-column nitrate was substantially compromised. DA - 2001/// PY - 2001/// DO - 10.1016/S0981-9428(01)01278-5 VL - 39 IS - 7-8 SP - 583-593 SN - 0981-9428 KW - carbon KW - eelgrass KW - light KW - nitrate reductase KW - oxygen KW - seagrass KW - Zostera marina ER - TY - JOUR TI - Identification of a P2X7 receptor in GH(4)C(1) rat pituitary cells: A potential target for a bioactive substance produced by Pfiesteria piscicida AU - Kimm-Brinson, KL AU - Moeller, PDR AU - Barbier, M AU - Glasgow, H AU - Burkholder, JM AU - Ramsdell, JS T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/5// PY - 2001/5// DO - 10.2307/3454703 VL - 109 IS - 5 SP - 457-462 SN - 1552-9924 KW - c-fos KW - GH(4)C(1) KW - P2X7 KW - Pfiesteria KW - pituitary KW - purinergic KW - toxin ER - TY - JOUR TI - Overview and present status of the toxic Pfiesteria complex (Dinophyceae) AU - Burkholder, JM AU - Glasgow, HB AU - Deamer-Melia, N T2 - PHYCOLOGIA AB - This paper reviews the Pfiesteria issue and Pfiesteria science and presents new information on variation in toxicity among Pfiesteria strains, culture effects on their toxicity, the trophic interactions of Pfiesteria spp ., and impacts on fish and mammals. We also assess Pfiesteria spp. impacts on fish in comparison to certain other estuarine dinoflagellates of similar appearance. Species of the toxic Pfiesteria complex (TPC) thus far include P. piscicida and P. shumwayae. These species share morphological and genetic similarities, and both have toxic strains that (1) show strong attraction to live fish;(2) exhibit toxicity that is triggered by live fish or their fresh tissues and excreta; and (3) produce toxin(s) that cause fish stress, disease and death under ecologically relevant conditions (the standardized fish bioassay process involves testing live Pfiesteria cells at similar densities to those encountered during Pfiesteria-related fish kill/disease events). Both Pfiesteria species also have a complex life cycle with multiple amoeboid, flagellated and cyst stages, several of which are ichthyotoxic. TPC species are eurythermal and euryhaline, with prey spanning the estuarine food web, from bacteria to mammalian tissues. They can be stimulated directly or indirectly by nitrogen and phosphorus enrichment. Toxic strains can be either actively or potentially toxic (the TOX-A and TOX-B functional types, respectively); in addition, c.40% of randomly isolated clones have been found to be benign [the noninducible or NON-IND functional type, which apparently lacks the ability to produce bioactive substances (toxins) that cause fish disease or death]. These functional types differ significantly in response to algal prey, predators, nutrients and fish. Moreover, as an apparent artifact of culture conditions, toxic strains generally lose their ability to cause fish death and disease and become NON-IND within weeks to months. At low cell densities, toxic strains can be causative agents of acute and/or chronic diffuse and focal lesions and of other fish diseases, as demonstrated in fish bioassays. A partially purified, water-soluble Pjiesteria toxin disrupts calcium metabolism in rat pituitary cells and mimics an adenosine triphosphate neurotransmitter that targets P2X7 purinoreceptors found predominantly on immune cells. Respiratory, visual, and neurological impacts have been sustained by people exposed to aerosols from fish-killing Pfiesteria cultures or to water and aerosols during estuarine fish kills associated with toxic Pfiesteria. Neurocognitive impacts from exposure to toxic Pfiesteria have been replicated experimentally in small mammals. Toxic strains of Pfiesteria species have been confirmed from mid-Atlantic and Gulf Coast estuaries in the United States and from northern Europe and New Zealand, indicating that these toxic dinoflagellates are cosmopolitan in distribution. DA - 2001/5// PY - 2001/5// DO - 10.2216/i0031-8884-40-3-186.1 VL - 40 IS - 3 SP - 186-214 SN - 2330-2968 ER - TY - JOUR TI - A second species of ichthyotoxic Pfiesteria (Dinamoebales, Dinophyceae) AU - Glasgow, HB AU - Burkholder, JM AU - Morton, SL AU - Springer, J T2 - PHYCOLOGIA AB - A second toxic species within the family Pfiesteriaceae, Pfiesteria shumwayae Glasgow & Burkholder sp. nov., is described from the New River Estuary and the Neuse Estuary of the Albemarle-Pamlico Estuarine Ecosystem, USA. The species is polymorphic and multiphasic, with flagellated, amoeboid and cyst stages. The flagellated zoospores (diameter 8–24 μm) have permanently condensed chromosomes (mesokaryotic nucleus); a chrysophyte-like cyst (diameter 6–25 μm)with organic scales and bracts; and thin thecal plates arranged in a Kofoidian series of Po, cp, X, 4′, la, 6″, 6c, 4s, 5″′, 2″″. The benthic filopodial (filose), lobopodia1 (lobose) and rhizopodial amoeboid stages (5–250 μm) have an outer covering that ranges from rough to smooth in texture, depending on the stage of origin and the prey source. Pfiesteria shumwayae amoebae have a normal eukaryote nucleus and cysts of multiple sizes (diameter 4–25 μm) with a reticulate outer covering. Toxic strains of the two Pfiesteria species have overlapping distributions in the mid-Atlantic and southeastern United States and Scandinavia, with toxic P. shumwayae also having been verified from New Zealand. Pfiesteria shumwayae is similar to P. piscicida in its complex life cycle, general nutrition, attraction to live fish prey, and ichthyotoxic activity that is stimulated by the presence of live fish or their fresh tissues and excreta. However, it can be distinguished from P. piscicida morphologically by having six precingular plates and a four-sided la plate, as well as genetically, on the basis of its ISS ribosomal DNA sequence. DA - 2001/5// PY - 2001/5// DO - 10.2216/i0031-8884-40-3-234.1 VL - 40 IS - 3 SP - 234-245 SN - 2330-2968 ER - TY - JOUR TI - Species of the toxic Pfiesteria complex, and the importance of functional type in data interpretation AU - Burkholder, JM AU - Glasgow, HB AU - Deamer-Melia, NJ AU - Springer, J AU - Parrow, MW AU - Zhang, C AU - Cancellieri, PJ T2 - ENVIRONMENTAL HEALTH PERSPECTIVES DA - 2001/10// PY - 2001/10// DO - 10.2307/3454912 VL - 109 SP - 667-679 SN - 1552-9924 KW - amoebae KW - complex life cycle KW - culture KW - dinoflagellates KW - estuaries KW - fish KW - noninducible KW - nutrients KW - strains KW - toxic Pfiesteria complex ER -