Tod Leighfield - Academia.edu (original) (raw)
Papers by Tod Leighfield
research.myfwc.com
... References SL Morton, TA Leighfield, BL Haynes, DL Petitpain, M. A. Busman, PDR Moeller, L. B... more ... References SL Morton, TA Leighfield, BL Haynes, DL Petitpain, M. A. Busman, PDR Moeller, L. Bean, J. McGowan, J. John W. Hurst, and FM Van Dolah, J. Shellfish ... DO Mountfort, G. Kennedy, I. Garthwaite, MA Quilliam, P. Truman, and DJ Hannah, Toxicon 37, 909922 (1999). ...
PLOS ONE, 2021
Despite a long-documented history of severe harmful algal blooms (HABs) in New England coastal wa... more Despite a long-documented history of severe harmful algal blooms (HABs) in New England coastal waters, corresponding HAB-associated marine mammal mortality events in this region are far less frequent or severe relative to other regions where HABs are common. This long-term survey of the HAB toxins saxitoxin (STX) and domoic acid (DA) demonstrates significant and widespread exposure of these toxins in New England marine mammals, across multiple geographic, temporal and taxonomic groups. Overall, 19% of the 458 animals tested positive for one or more toxins, with 15% and 7% testing positive for STX and DA, respectively. 74% of the 23 different species analyzed demonstrated evidence of toxin exposure. STX was most prevalent in Maine coastal waters, most frequently detected in common dolphins (Delphinus delphis), and most often detected during July and October. DA was most prevalent in animals sampled in offshore locations and in bycaught animals, and most frequently detected in mystice...
http://www-pub.iaea.org/MTCD/Publications/PDF/TE-1729\_web.pdf
Harmful Algae, 2009
Plankton surveys, between 2001 and 2005 along the Russian Caucasian Black Sea Coast, revealed Din... more Plankton surveys, between 2001 and 2005 along the Russian Caucasian Black Sea Coast, revealed Dinophysis rotundata, D. caudata and Prorocentrum lima as the most ubiquitous of the known dinoflagellates associated with diarrhetic shellfish poisoning (DSP). Dinophysis spp. were first observed during the spring phytoplankton succession and persist throughout the late summer phytoplankton peak. The highest total concentration, 3000 cells/L, of D. rotundata and D. caudata was observed in April 2001. Unlike Dinophysis, P. lima was rarely observed in plankton samples but closely followed storm events with maximum cell counts of P. lima occurred in July 2002. The presence of Dinophysis in mussel (Mytilus galloprovincialis) hepatopancreas correlated with concentration with Dinophysis observed in the plankton samples. Conversely, P. lima could be found in most hepatopancreas samples collected during the May to October period. Therefore, planktonic concentration of P. lima does not reflect its availability for and consumption by shellfish. Samples of mussel hepatopancreas, from August 2002, with a corresponding Dinophysis concentration of 250 cells/L and no observable P. lima, were found to contain 0.03 ng OAE/g. This sample analyses by LC-MS/MS displayed okadaic acid (OA) and related congeners (DTX1) along with the pectinotoxins (PTX2 and PTX2sa). Highest observed levels of P. lima-induced DSP-toxicity in hepatopancreas was 0.41 g OAequivalents/g corresponded to the highest observed planktonic cell counts of P. lima, 300 cell/L in August 2001. Cultures isolated from this sample were found to produce OA, DTX1 and their related diol esters. These data reveal a threat, represented by DSP-toxic species, at Black Sea coasts, and provide grounds for the introduction of phycotoxin control measures in the region.
NOAA Technical …, 1998
Page 49. Assessment of the Involvement of Algal Toxins in the 1994 Texas Fish Kills FRANCES M. VA... more Page 49. Assessment of the Involvement of Algal Toxins in the 1994 Texas Fish Kills FRANCES M. VAN DOLAH GREGORY]. DOUCETTE TOD A. LETGHFIELD Charleston Laboratory* Southeast Fisheril's Science Center National ...
Journal of AOAC International, May 1, 2012
The recommendation was approved by the Method Committee on Paralytic Shellfish Toxins as First Ac... more The recommendation was approved by the Method Committee on Paralytic Shellfish Toxins as First Action. See "Methods News," (2011) Inside Laboratory Management, January/February issue. This publication does not constitute an endorsement of any commercial product or intend to be an opinion beyond scientific or other results obtained by the National Oceanic and Atmospheric Administration (NOAA). No reference shall be made to NOAA, or this publication furnished by NOAA, to any advertising or sales promotion which would indicate or imply that NOAA recommends or endorses any proprietary product mentioned herein, or which has as its purpose an interest to cause the advertised product to be used or purchased because of this publication.
Marine Environmental Research
Toxins
Many communities in Southeast Alaska harvest shellfish such as mussels and clams as an important ... more Many communities in Southeast Alaska harvest shellfish such as mussels and clams as an important part of a subsistence or traditional diet. Harmful algal blooms (HABs) of phytoplankton such as Alexandrium spp. produce toxins that can accumulate in shellfish tissues to concentrations that can pose a hazard for human health. Since 2013, several tribal governments and communities have pooled resources to form the Southeast Alaska Tribal Ocean Research (SEATOR) network, with the goal of minimizing risks to seafood harvest and enhancing food security. SEATOR monitors toxin concentrations in shellfish and collects and consolidates data on environmental variables that may be important predictors of toxin levels such as sea surface temperature and salinity. Data from SEATOR are publicly available and are encouraged to be used for the development and testing of predictive algorithms that could improve seafood risk assessment in Southeast Alaska. To date, more than 1700 shellfish samples have...
Harmful Algae, Oct 1, 2006
... Authors are thankful to Dr. Irina Sukhanova and Dr. Violeta Velikova for valuable advice and ... more ... Authors are thankful to Dr. Irina Sukhanova and Dr. Violeta Velikova for valuable advice and consultations during this work and to William ... Fedorov et al., 1980 VD Fedorov, LS Zhitina, MNKorsak and TI Belaya, Distribution of phytoplankton biomass and production in the White ...
Harmful algae 2002 : proceedings of the Xth International Conference on Harmful Algae, St. Pete Beach, Florida, USA, October 21-25, 2002 / edited by Karen A. Steidinger [and others]. International Conference on Harmful Algae (10th : 200...
A thirteen-laboratory comparative study tested the performance of four methods as alternatives to... more A thirteen-laboratory comparative study tested the performance of four methods as alternatives to mouse bioassay for the determination of brevetoxins in shellfish. The methods were N2a neuroblastoma cell assay, two variations of the sodium channel receptor binding assay, competitive ELISA, and LC/MS. Three to five laboratories independently performed each method using centrally prepared spiked and naturally incurred test samples. Competitive ELISA and receptor binding (96-well format) compared most favorably with mouse bioassay. Between-laboratory relative standard deviations (RSDR) ranged from 10 to 20% for ELISA and 14 to 31% for receptor binding. Within-laboratory (RSDr) ranged from 6 to 15% for ELISA, and 5 to 31% for receptor binding. Cell assay was extremely sensitive but data variation rendered it unsuitable for statistical treatment. LC/MS performed as well as ELISA on spiked test samples but was inordinately affected by lack of toxin-metabolite standards, uniform instrument...
Journal Of Shellfish …, 1999
Evidence of diarrhetic shellfish poisoning along the coast of Maine. SL Morton, TA Leighfield, BL... more Evidence of diarrhetic shellfish poisoning along the coast of Maine. SL Morton, TA Leighfield, BL Haynes, DL Petitpain, MA Busman, PDR Moeller, L Bean, J McGowan, JW Hurst Jr, FM Van Dolah Journal of Shellfish Research 18:22, 681-686, 12/1999. ...
Harmful Algae
The first recorded bloom of Karenia spp., resulting in brevetoxin in oysters, in the low salinity... more The first recorded bloom of Karenia spp., resulting in brevetoxin in oysters, in the low salinity waters of the Northern Gulf of Mexico (NGOMEX) occurred in November 1996. It raised questions about the salinity tolerance of Karenia spp., previously considered unlikely to occur at salinities <24 psu, and the likelihood that the bloom would reoccur in the NGOMEX. Salinity was investigated as a factor controlling Karenia spp. abundance in the field, using data from the NGOMEX 1996 bloom and Florida coastal waters from 1954 to 2004, and growth and toxin production in cultures of Karenia brevis (Davis) G. Hansen and Moestrup. During the NGOMEX bloom, Karenia spp. occurred much more frequently at low salinities than in Florida coastal waters over the last 50 years. The data suggest that the NGOMEX bloom started on the NW Florida Shelf, an area with a higher frequency of Karenia spp. at low salinities than the rest of Florida, and was transported by an unusual westward surface current c...
Chemical research in toxicology, Jan 21, 2014
Brevetoxins produced during algal blooms of the dinoflagellate Karenia are metabolized by shellfi... more Brevetoxins produced during algal blooms of the dinoflagellate Karenia are metabolized by shellfish into reduction, oxidation, and conjugation products. Brevetoxin metabolites comprising amino acid- and lipid conjugates account for a large proportion of the toxicity associated with the consumption of toxic shellfish. However, the disposition of these brevetoxin metabolites has not been established. Using intravenous exposure to C57BL/6 mice, we investigated the disposition in the body of three radiolabeled brevetoxin metabolites. Amino acid-brevetoxin conjugates represented by S-desoxy-BTX-B2 (cysteine-BTX-B) and lipid-brevetoxin conjugates represented by N-palmitoyl-S-desoxy-BTX-B2 were compared to dihydro-BTX-B. Tissue concentration profiles were unique to each of the brevetoxin metabolites tested, with dihydro-BTX-B being widely distributed to all tissues, S-desoxy-BTX-B2 concentrated in kidney, and N-palmitoyl-S-desoxy-BTX-B2 having the highest concentrations in spleen, liver, a...
Journal of AOAC International
A single-laboratory validation (SLV) study was conducted for the microplate receptor binding assa... more A single-laboratory validation (SLV) study was conducted for the microplate receptor binding assay (RBA) for paralytic shellfish poisoning (PSP) toxins in shellfish. The basis of the assay is the competition between [3H]saxitoxin (STX) and STX in a standard or sample for binding to the voltage dependent sodium channel. A calibration curve is generated by the addition of 0.01-1000 nM STX, which results in the concentration dependent decrease in [3H]STX-receptor complexes formed and serves to quantify STX in unknown samples. This study established the LOQ, linearity, recovery, accuracy, and precision of the assay for determining PSP toxicity in shellfish extracts, as performed by a single analyst on multiple days. The standard curve obtained on 5 independent days resulted in a half-maximal inhibition (IC50) of 2.3 nM STX +/- 0.3 (RSD = 10.8%) with a slope of 0.96 +/- 0.06 (RSD = 6.3%) and a dynamic range of 1.2-10.0 nM. The LOQ was 5.3 microg STX equivalents/100 g shellfish. Linearity...
![Research paper thumbnail of Spatial and temporal trends of the toxic diatom Pseudo-nitzschia in the Southeastern Atlantic United States [2012]](https://attachments.academia-assets.com/42971257/thumbnails/1.jpg)
](Data collected by NOAA Phytoplankton Monitoring Network volunteers, from the beginning of the pro... more Data collected by NOAA Phytoplankton Monitoring Network volunteers, from the beginning of the program (2001) through 2010, was used to assess the spatial and temporal trends of Pseudo-nitzschia spp. from North Carolina through northern Florida along the southeastern US coastline. Pseudo-nitzschia spp. was present from North Carolina to Florida, and was most common in North and South Carolina. Across the majority of the Atlantic southeast US, the highest rates of occurrence were observed in late summer, early fall, with most areas experiencing the lowest rate of occurrence in the spring. The Outer Banks of North Carolina, however, experienced a peak of occurrence in late winter to early spring in addition to a late summer, early fall peak. Pseudo-nitzschia was found in temperatures ranging from less than 5 8C to 35 8C and salinities from 5 to 37. Six unique bloom events were documented during this period of nine years, three of which contained detectable levels of domoic acid. The majority of these bloom events and all of the toxic events occurred in the Outer Banks of North Carolina. Given the extent and intensity of coverage afforded by the NOAA PMN, this program provides the optimal approach to not only assess past trends but to monitor environmental changes and emerging trends in the dynamics of this toxigenic species. Understanding the dynamics of this species allows resource managers to better predict the threats associated with domoic acid.
research.myfwc.com
... References SL Morton, TA Leighfield, BL Haynes, DL Petitpain, M. A. Busman, PDR Moeller, L. B... more ... References SL Morton, TA Leighfield, BL Haynes, DL Petitpain, M. A. Busman, PDR Moeller, L. Bean, J. McGowan, J. John W. Hurst, and FM Van Dolah, J. Shellfish ... DO Mountfort, G. Kennedy, I. Garthwaite, MA Quilliam, P. Truman, and DJ Hannah, Toxicon 37, 909922 (1999). ...
PLOS ONE, 2021
Despite a long-documented history of severe harmful algal blooms (HABs) in New England coastal wa... more Despite a long-documented history of severe harmful algal blooms (HABs) in New England coastal waters, corresponding HAB-associated marine mammal mortality events in this region are far less frequent or severe relative to other regions where HABs are common. This long-term survey of the HAB toxins saxitoxin (STX) and domoic acid (DA) demonstrates significant and widespread exposure of these toxins in New England marine mammals, across multiple geographic, temporal and taxonomic groups. Overall, 19% of the 458 animals tested positive for one or more toxins, with 15% and 7% testing positive for STX and DA, respectively. 74% of the 23 different species analyzed demonstrated evidence of toxin exposure. STX was most prevalent in Maine coastal waters, most frequently detected in common dolphins (Delphinus delphis), and most often detected during July and October. DA was most prevalent in animals sampled in offshore locations and in bycaught animals, and most frequently detected in mystice...
http://www-pub.iaea.org/MTCD/Publications/PDF/TE-1729\_web.pdf
Harmful Algae, 2009
Plankton surveys, between 2001 and 2005 along the Russian Caucasian Black Sea Coast, revealed Din... more Plankton surveys, between 2001 and 2005 along the Russian Caucasian Black Sea Coast, revealed Dinophysis rotundata, D. caudata and Prorocentrum lima as the most ubiquitous of the known dinoflagellates associated with diarrhetic shellfish poisoning (DSP). Dinophysis spp. were first observed during the spring phytoplankton succession and persist throughout the late summer phytoplankton peak. The highest total concentration, 3000 cells/L, of D. rotundata and D. caudata was observed in April 2001. Unlike Dinophysis, P. lima was rarely observed in plankton samples but closely followed storm events with maximum cell counts of P. lima occurred in July 2002. The presence of Dinophysis in mussel (Mytilus galloprovincialis) hepatopancreas correlated with concentration with Dinophysis observed in the plankton samples. Conversely, P. lima could be found in most hepatopancreas samples collected during the May to October period. Therefore, planktonic concentration of P. lima does not reflect its availability for and consumption by shellfish. Samples of mussel hepatopancreas, from August 2002, with a corresponding Dinophysis concentration of 250 cells/L and no observable P. lima, were found to contain 0.03 ng OAE/g. This sample analyses by LC-MS/MS displayed okadaic acid (OA) and related congeners (DTX1) along with the pectinotoxins (PTX2 and PTX2sa). Highest observed levels of P. lima-induced DSP-toxicity in hepatopancreas was 0.41 g OAequivalents/g corresponded to the highest observed planktonic cell counts of P. lima, 300 cell/L in August 2001. Cultures isolated from this sample were found to produce OA, DTX1 and their related diol esters. These data reveal a threat, represented by DSP-toxic species, at Black Sea coasts, and provide grounds for the introduction of phycotoxin control measures in the region.
NOAA Technical …, 1998
Page 49. Assessment of the Involvement of Algal Toxins in the 1994 Texas Fish Kills FRANCES M. VA... more Page 49. Assessment of the Involvement of Algal Toxins in the 1994 Texas Fish Kills FRANCES M. VAN DOLAH GREGORY]. DOUCETTE TOD A. LETGHFIELD Charleston Laboratory* Southeast Fisheril&#x27;s Science Center National ...
Journal of AOAC International, May 1, 2012
The recommendation was approved by the Method Committee on Paralytic Shellfish Toxins as First Ac... more The recommendation was approved by the Method Committee on Paralytic Shellfish Toxins as First Action. See "Methods News," (2011) Inside Laboratory Management, January/February issue. This publication does not constitute an endorsement of any commercial product or intend to be an opinion beyond scientific or other results obtained by the National Oceanic and Atmospheric Administration (NOAA). No reference shall be made to NOAA, or this publication furnished by NOAA, to any advertising or sales promotion which would indicate or imply that NOAA recommends or endorses any proprietary product mentioned herein, or which has as its purpose an interest to cause the advertised product to be used or purchased because of this publication.
Marine Environmental Research
Toxins
Many communities in Southeast Alaska harvest shellfish such as mussels and clams as an important ... more Many communities in Southeast Alaska harvest shellfish such as mussels and clams as an important part of a subsistence or traditional diet. Harmful algal blooms (HABs) of phytoplankton such as Alexandrium spp. produce toxins that can accumulate in shellfish tissues to concentrations that can pose a hazard for human health. Since 2013, several tribal governments and communities have pooled resources to form the Southeast Alaska Tribal Ocean Research (SEATOR) network, with the goal of minimizing risks to seafood harvest and enhancing food security. SEATOR monitors toxin concentrations in shellfish and collects and consolidates data on environmental variables that may be important predictors of toxin levels such as sea surface temperature and salinity. Data from SEATOR are publicly available and are encouraged to be used for the development and testing of predictive algorithms that could improve seafood risk assessment in Southeast Alaska. To date, more than 1700 shellfish samples have...
Harmful Algae, Oct 1, 2006
... Authors are thankful to Dr. Irina Sukhanova and Dr. Violeta Velikova for valuable advice and ... more ... Authors are thankful to Dr. Irina Sukhanova and Dr. Violeta Velikova for valuable advice and consultations during this work and to William ... Fedorov et al., 1980 VD Fedorov, LS Zhitina, MNKorsak and TI Belaya, Distribution of phytoplankton biomass and production in the White ...
Harmful algae 2002 : proceedings of the Xth International Conference on Harmful Algae, St. Pete Beach, Florida, USA, October 21-25, 2002 / edited by Karen A. Steidinger [and others]. International Conference on Harmful Algae (10th : 200...
A thirteen-laboratory comparative study tested the performance of four methods as alternatives to... more A thirteen-laboratory comparative study tested the performance of four methods as alternatives to mouse bioassay for the determination of brevetoxins in shellfish. The methods were N2a neuroblastoma cell assay, two variations of the sodium channel receptor binding assay, competitive ELISA, and LC/MS. Three to five laboratories independently performed each method using centrally prepared spiked and naturally incurred test samples. Competitive ELISA and receptor binding (96-well format) compared most favorably with mouse bioassay. Between-laboratory relative standard deviations (RSDR) ranged from 10 to 20% for ELISA and 14 to 31% for receptor binding. Within-laboratory (RSDr) ranged from 6 to 15% for ELISA, and 5 to 31% for receptor binding. Cell assay was extremely sensitive but data variation rendered it unsuitable for statistical treatment. LC/MS performed as well as ELISA on spiked test samples but was inordinately affected by lack of toxin-metabolite standards, uniform instrument...
Journal Of Shellfish …, 1999
Evidence of diarrhetic shellfish poisoning along the coast of Maine. SL Morton, TA Leighfield, BL... more Evidence of diarrhetic shellfish poisoning along the coast of Maine. SL Morton, TA Leighfield, BL Haynes, DL Petitpain, MA Busman, PDR Moeller, L Bean, J McGowan, JW Hurst Jr, FM Van Dolah Journal of Shellfish Research 18:22, 681-686, 12/1999. ...
Harmful Algae
The first recorded bloom of Karenia spp., resulting in brevetoxin in oysters, in the low salinity... more The first recorded bloom of Karenia spp., resulting in brevetoxin in oysters, in the low salinity waters of the Northern Gulf of Mexico (NGOMEX) occurred in November 1996. It raised questions about the salinity tolerance of Karenia spp., previously considered unlikely to occur at salinities <24 psu, and the likelihood that the bloom would reoccur in the NGOMEX. Salinity was investigated as a factor controlling Karenia spp. abundance in the field, using data from the NGOMEX 1996 bloom and Florida coastal waters from 1954 to 2004, and growth and toxin production in cultures of Karenia brevis (Davis) G. Hansen and Moestrup. During the NGOMEX bloom, Karenia spp. occurred much more frequently at low salinities than in Florida coastal waters over the last 50 years. The data suggest that the NGOMEX bloom started on the NW Florida Shelf, an area with a higher frequency of Karenia spp. at low salinities than the rest of Florida, and was transported by an unusual westward surface current c...
Chemical research in toxicology, Jan 21, 2014
Brevetoxins produced during algal blooms of the dinoflagellate Karenia are metabolized by shellfi... more Brevetoxins produced during algal blooms of the dinoflagellate Karenia are metabolized by shellfish into reduction, oxidation, and conjugation products. Brevetoxin metabolites comprising amino acid- and lipid conjugates account for a large proportion of the toxicity associated with the consumption of toxic shellfish. However, the disposition of these brevetoxin metabolites has not been established. Using intravenous exposure to C57BL/6 mice, we investigated the disposition in the body of three radiolabeled brevetoxin metabolites. Amino acid-brevetoxin conjugates represented by S-desoxy-BTX-B2 (cysteine-BTX-B) and lipid-brevetoxin conjugates represented by N-palmitoyl-S-desoxy-BTX-B2 were compared to dihydro-BTX-B. Tissue concentration profiles were unique to each of the brevetoxin metabolites tested, with dihydro-BTX-B being widely distributed to all tissues, S-desoxy-BTX-B2 concentrated in kidney, and N-palmitoyl-S-desoxy-BTX-B2 having the highest concentrations in spleen, liver, a...
Journal of AOAC International
A single-laboratory validation (SLV) study was conducted for the microplate receptor binding assa... more A single-laboratory validation (SLV) study was conducted for the microplate receptor binding assay (RBA) for paralytic shellfish poisoning (PSP) toxins in shellfish. The basis of the assay is the competition between [3H]saxitoxin (STX) and STX in a standard or sample for binding to the voltage dependent sodium channel. A calibration curve is generated by the addition of 0.01-1000 nM STX, which results in the concentration dependent decrease in [3H]STX-receptor complexes formed and serves to quantify STX in unknown samples. This study established the LOQ, linearity, recovery, accuracy, and precision of the assay for determining PSP toxicity in shellfish extracts, as performed by a single analyst on multiple days. The standard curve obtained on 5 independent days resulted in a half-maximal inhibition (IC50) of 2.3 nM STX +/- 0.3 (RSD = 10.8%) with a slope of 0.96 +/- 0.06 (RSD = 6.3%) and a dynamic range of 1.2-10.0 nM. The LOQ was 5.3 microg STX equivalents/100 g shellfish. Linearity...
Data collected by NOAA Phytoplankton Monitoring Network volunteers, from the beginning of the pro... more Data collected by NOAA Phytoplankton Monitoring Network volunteers, from the beginning of the program (2001) through 2010, was used to assess the spatial and temporal trends of Pseudo-nitzschia spp. from North Carolina through northern Florida along the southeastern US coastline. Pseudo-nitzschia spp. was present from North Carolina to Florida, and was most common in North and South Carolina. Across the majority of the Atlantic southeast US, the highest rates of occurrence were observed in late summer, early fall, with most areas experiencing the lowest rate of occurrence in the spring. The Outer Banks of North Carolina, however, experienced a peak of occurrence in late winter to early spring in addition to a late summer, early fall peak. Pseudo-nitzschia was found in temperatures ranging from less than 5 8C to 35 8C and salinities from 5 to 37. Six unique bloom events were documented during this period of nine years, three of which contained detectable levels of domoic acid. The majority of these bloom events and all of the toxic events occurred in the Outer Banks of North Carolina. Given the extent and intensity of coverage afforded by the NOAA PMN, this program provides the optimal approach to not only assess past trends but to monitor environmental changes and emerging trends in the dynamics of this toxigenic species. Understanding the dynamics of this species allows resource managers to better predict the threats associated with domoic acid.