Stability of Saxitoxin in 50% Methanol Fecal Extracts and Raw Feces from Bowhead Whales (<i>Balaena mysticetus</i>)
In recent decades, harmful algal blooms (HABs) producing paralytic shellfish toxins (including saxitoxin, STX) have become increasingly frequent in the marine waters of Alaska, USA, subjecting Pacific Arctic and subarctic communities and wildlife to increased toxin exposure risks. Research on the ri...
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| Format: | Article |
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MDPI AG
2022-08-01
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| Series: | Marine Drugs |
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| Online Access: | https://www.mdpi.com/1660-3397/20/9/547 |
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| author | Emily K. Bowers Raphaela Stimmelmayr Alicia Hendrix Kathi A. Lefebvre |
| author_facet | Emily K. Bowers Raphaela Stimmelmayr Alicia Hendrix Kathi A. Lefebvre |
| author_sort | Emily K. Bowers |
| collection | DOAJ |
| description | In recent decades, harmful algal blooms (HABs) producing paralytic shellfish toxins (including saxitoxin, STX) have become increasingly frequent in the marine waters of Alaska, USA, subjecting Pacific Arctic and subarctic communities and wildlife to increased toxin exposure risks. Research on the risks of HAB toxin exposures to marine mammal health commonly relies on the sampling of marine mammal gastrointestinal (GI) contents to quantify HAB toxins, yet no studies have been published testing the stability of STX in marine mammal GI matrices. An understanding of STX stability in test matrices under storage and handling conditions is imperative to the integrity of toxin quantifications and conclusions drawn thereby. Here, STX stability is characterized in field-collected bowhead whale feces (stored raw in several treatments) and in fecal extracts (50% methanol, MeOH) over multiple time points. Toxin stability, as the percent of initial concentration (T0), was reported for each storage treatment and time point. STX was stable (mean 99% T0) in 50% MeOH extracts over the 8-week study period, and there was no significant difference in STX concentrations quantified in split fecal samples extracted in 80% ethanol (EtOH) and 50% MeOH. STX was also relatively stable in raw fecal material stored in the freezer (mean 94% T0) and the refrigerator (mean 93% T0) up to 8 weeks. STX degraded over time in the room-temperature dark, room-temperature light, and warm treatments to means of 48 ± 1.9, 38 ± 2.8, and 20 ± 0.7% T0, respectively, after 8 weeks (mean ± standard error; SE). Additional opportunistically analyzed samples frozen for ≤4.5 years also showed STX to be relatively stable (mean 97% T0). Mean percent of T0 was measured slightly above 100% in some extracts following some treatments, and (most notably) at some long-term frozen time points, likely due to evaporation from samples causing STX to concentrate, or variability between ELISA plates. Overall, these results suggest that long-term frozen storage of raw fecal samples and the analysis of extracts within 8 weeks of extraction in 50% MeOH is sufficient for obtaining accurate STX quantifications in marine mammal fecal material without concerns about significant degradation. |
| first_indexed | 2024-03-09T23:20:07Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 1660-3397 |
| language | English |
| last_indexed | 2024-03-09T23:20:07Z |
| publishDate | 2022-08-01 |
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| series | Marine Drugs |
| spelling | doaj.art-0cfdea130ca84e4f93ab8dd726c41cbc2023-11-23T17:28:25ZengMDPI AGMarine Drugs1660-33972022-08-0120954710.3390/md20090547Stability of Saxitoxin in 50% Methanol Fecal Extracts and Raw Feces from Bowhead Whales (<i>Balaena mysticetus</i>)Emily K. Bowers0Raphaela Stimmelmayr1Alicia Hendrix2Kathi A. Lefebvre3Northwest Fisheries Science Center, Environmental and Fisheries Sciences Division, National Marine Fisheries Service, NOAA, 2725 Montlake Blvd E, Seattle, WA 98112, USAThe North Slope Borough Department of Wildlife Management, P.O. Box 69, Utqiagvik, AK 99723, USADepartment of Environmental and Occupational Health Sciences, University of Washington, Box 351618, Seattle, WA 98195, USANorthwest Fisheries Science Center, Environmental and Fisheries Sciences Division, National Marine Fisheries Service, NOAA, 2725 Montlake Blvd E, Seattle, WA 98112, USAIn recent decades, harmful algal blooms (HABs) producing paralytic shellfish toxins (including saxitoxin, STX) have become increasingly frequent in the marine waters of Alaska, USA, subjecting Pacific Arctic and subarctic communities and wildlife to increased toxin exposure risks. Research on the risks of HAB toxin exposures to marine mammal health commonly relies on the sampling of marine mammal gastrointestinal (GI) contents to quantify HAB toxins, yet no studies have been published testing the stability of STX in marine mammal GI matrices. An understanding of STX stability in test matrices under storage and handling conditions is imperative to the integrity of toxin quantifications and conclusions drawn thereby. Here, STX stability is characterized in field-collected bowhead whale feces (stored raw in several treatments) and in fecal extracts (50% methanol, MeOH) over multiple time points. Toxin stability, as the percent of initial concentration (T0), was reported for each storage treatment and time point. STX was stable (mean 99% T0) in 50% MeOH extracts over the 8-week study period, and there was no significant difference in STX concentrations quantified in split fecal samples extracted in 80% ethanol (EtOH) and 50% MeOH. STX was also relatively stable in raw fecal material stored in the freezer (mean 94% T0) and the refrigerator (mean 93% T0) up to 8 weeks. STX degraded over time in the room-temperature dark, room-temperature light, and warm treatments to means of 48 ± 1.9, 38 ± 2.8, and 20 ± 0.7% T0, respectively, after 8 weeks (mean ± standard error; SE). Additional opportunistically analyzed samples frozen for ≤4.5 years also showed STX to be relatively stable (mean 97% T0). Mean percent of T0 was measured slightly above 100% in some extracts following some treatments, and (most notably) at some long-term frozen time points, likely due to evaporation from samples causing STX to concentrate, or variability between ELISA plates. Overall, these results suggest that long-term frozen storage of raw fecal samples and the analysis of extracts within 8 weeks of extraction in 50% MeOH is sufficient for obtaining accurate STX quantifications in marine mammal fecal material without concerns about significant degradation.https://www.mdpi.com/1660-3397/20/9/547marine mammalstoxin degradationharmful algal bloom toxinsstorage conditionsELISAsaxitoxin |
| spellingShingle | Emily K. Bowers Raphaela Stimmelmayr Alicia Hendrix Kathi A. Lefebvre Stability of Saxitoxin in 50% Methanol Fecal Extracts and Raw Feces from Bowhead Whales (<i>Balaena mysticetus</i>) Marine Drugs marine mammals toxin degradation harmful algal bloom toxins storage conditions ELISA saxitoxin |
| title | Stability of Saxitoxin in 50% Methanol Fecal Extracts and Raw Feces from Bowhead Whales (<i>Balaena mysticetus</i>) |
| title_full | Stability of Saxitoxin in 50% Methanol Fecal Extracts and Raw Feces from Bowhead Whales (<i>Balaena mysticetus</i>) |
| title_fullStr | Stability of Saxitoxin in 50% Methanol Fecal Extracts and Raw Feces from Bowhead Whales (<i>Balaena mysticetus</i>) |
| title_full_unstemmed | Stability of Saxitoxin in 50% Methanol Fecal Extracts and Raw Feces from Bowhead Whales (<i>Balaena mysticetus</i>) |
| title_short | Stability of Saxitoxin in 50% Methanol Fecal Extracts and Raw Feces from Bowhead Whales (<i>Balaena mysticetus</i>) |
| title_sort | stability of saxitoxin in 50 methanol fecal extracts and raw feces from bowhead whales i balaena mysticetus i |
| topic | marine mammals toxin degradation harmful algal bloom toxins storage conditions ELISA saxitoxin |
| url | https://www.mdpi.com/1660-3397/20/9/547 |
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