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Dinoflagellate species belonging to the genera Gambierdiscus and Fukuyoa produce ciguatoxins (CTXs), potent neurotoxins that concentrate in fish causing ciguatera fish poisoning (CFP) in humans. While the structures and toxicities of ciguatoxins isolated from fish in the Pacific and Caribbean are known, there are few data on the variation in toxicity between and among species of Gambierdiscus and Fukuyoa. Quantifying the differences in species-specific toxicity is especially important to developing an effective cell-based risk assessment strategy for CFP. This study analyzed the ciguatoxicity of 33 strains representing seven Gambierdiscus and one Fukuyoa species using a cell based Neuro-2a cytotoxicity assay. All strains were isolated from either the Caribbean or Gulf of Mexico. The average toxicity of each species was inversely proportional to growth rate, suggesting an evolutionary trade-off between an investment in growth versus the production of defensive compounds. While there is 2- to 27-fold variation in toxicity within species, there was a 1740-fold difference between the least and most toxic species. Consequently, production of CTX or CTX-like compounds is more dependent on the species present than on the random occurrence of high or low toxicity strains. Seven of the eight species tested (G. belizeanus, G. caribaeus, G. carolinianus, G. carpenteri, Gambierdiscus ribotype 2, G. silvae and F. ruetzleri) exhibited low toxicities, ranging from 0 to 24.5 fg CTX3C equivalents cell-1, relative to G. excentricus, which had a toxicity of 469 fg CTX3C eq. cell-1. Isolates of G. excentricus from other regions have shown similarly high toxicities. If the hypothesis that G. excentricus is the primary source of ciguatoxins in the Atlantic is confirmed, it should be possible to identify areas where CFP risk is greatest by monitoring only G. excentricus abundance using species-specific molecular assays.

Paralytic shellfish poisoning (PSP) is a pervasive human health concern associated with subsistence, recreationally and commercially harvested Alaskan shellfish. PSP is caused by saxitoxins (STX), a family of structurally similar neurotoxins produced by the marine microalgae Alexandrium catenella (formerly A. fundyense ). These toxins accumulate in filter-feeding shellfish such as clams, mussels and oysters. While PSP is commonly associated with consuming bivalves, toxic STX levels can also be found in crab viscera (crab butter). The first cases of PSP from consuming Dungeness crab viscera ( Metacarcinus magister ) were reported in 1992. Although this incident and others did not involve commercially harvested crab, they did impact management of the Dungeness crab fishery in Alaska. Current regulations in southeast Alaska permit the sale of whole Dungeness crab, whereas those in the Kodiak Archipelago must have their viscera removed post-harvest to prevent PSP. This study examines the impacts of STXs and current regulations on the Alaskan crab fishery, with a focus on Dungeness crab. Data on commercial landings and the value of harvested Dungeness crab and processed products showed that regulations to protect human health, combined with market forces over the past 30 years, have shifted the fishery’s focus toward Dungeness crab products without viscera. The study also presents time series data on STX concentrations in Dungeness crab from 1992 to 2023, along with maps indicating collection locations and their associated toxicity levels. The same data for King crab ( Paralithodes or Lithodes spp.) and Tanner (Snow) crab ( Chionoecetes spp.) are included to assess the prevalence of STX in these commercially harvested species. Further, a preliminary analysis suggests regional variations in the toxicity of A. catenella strains could affect regional shellfish toxicity.

Butter clams (Saxidomus gigantea) are a staple in the subsistence diets of Alaskan Native communities and are also harvested recreationally. This filter–feeding species can accumulate saxitoxins (STXs), potent neurotoxins produced by late spring and summer blooms of the microalga Alexandrium catenella. The consumption of tainted clams can cause paralytic shellfish poisoning (PSP). Traditional beliefs and early reports on the efficacy of removing clam siphons have created the impression that cleaning butter clams by removing certain tissues makes them safe to eat. However, the toxin distribution within clams can vary over time, making the practice of cleaning butter clams unreliable. This study tested the effectiveness of the cleaning methods practiced by harvesters on Kodiak Island, Alaska. Specifically, butter clams were cleaned by removing different tissues to produce samples of “edible” tissues that were tested for STX content. The results were compared to historical data from a study conducted in Southeast Alaska from 1948 to 1949. Using these data, the risk for an average–sized man and woman consuming 200 g of edible tissue was calculated. The results showed that for clams containing >200 µg STX–equivalents 100 g edible tissue−1, no cleaning method reduced the concentration of STXs in the remaining tissue below the regulatory limit. Meals containing >900 µg STX–equivalents 100 g edible tissue−1 posed a substantial risk of moderate or severe symptoms. No cleaning method assured that untested butter clams are safe to eat.

Litaker R.W., Vandersea M.W., Faust M.A., Kibler S.R., Chinain M., Holmes M.J., Holland W.C. and Tester P.A. 2009. Taxonomy of Gambierdiscus including four new species, Gambierdiscus caribaeus, Gambierdiscus carolinianus, Gambierdiscus carpenteri and Gambierdiscus ruetzleri (Gonyaulacales, Dinophyceae). Phycologia 48: 344-390. DOI: 10.2216/07-15.1 Gambierdiscus species produce toxins that cause ciguatera fish poisoning (CFP), the most common nonbacterial illness associated with fish consumption worldwide. Understanding the role that individual Gambierdiscus species play in causing CFP is hampered because the morphologically similar species in the genus are difficult to distinguish. Ambiguities in the description of the type species Gambierdiscus toxicus also exist. This paper presents detailed line drawings along with additional scanning electron microscopy (SEM) and light micrographs to more fully characterize the six known Gambierdiscus species in addition to describing four new species, Gambierdiscus caribaeus sp. nov., Gambierdiscus carolinianus sp. nov., Gambierdiscus carpenteri sp. nov., and Gambierdiscus ruetzleri sp. nov. All four of the new species are photosynthetic and epibenthic and have a Kofoidian plate formula of Po, 3′, 7″, 6C, 6 or 7S, 5′″, 1p, and 2″″. Establishment of these species is supported by both morphological differences and three independent phylogenetic analyses utilizing small-subunit, as well as D1-D3 and D8-D10 large-subunit rDNA gene sequences. During the course of this study it became apparent that the description of the type species, G. toxicus, included more than one species. Since no type material exists we propose that Fig. 1 in Adachi and Fukuyo (1979) be designated as the lectotype for this species and that the epithecal view of isolate GTT-91 shown in Fig. 1 from Chinain et al. (1999) be designated as the epitype. The GTT-91 isolate has been well characterized genetically and the original SEM stub of this isolate archived at the Smithsonian Institution has been re-examined to provide a more detailed morphological analysis of the epitype.

Paralytic shellfish poisoning (PSP) poses a serious health threat in Alaska and prevents effective utilization of shellfish resources by subsistence and recreational harvesters. Substantial economic losses also affect shellfish growers during PSP events. The toxins responsible for PSP are produced by dinoflagellates in the genus Alexandrium. Despite the persistent threat posed by PSP and the long history of shellfish toxicity research, there is still confusion concerning the Alexandrium species that cause PSP in Alaska. The primary objective of this study was to identify the toxic Alexandrium species present in Alaska and to develop polymerase chain reaction (PCR) assays for use in screening phytoplankton and sediment samples. Before developing the PCR assays for this study, we evaluated published assays and many were not adequate because of primer dimer formation or because of cross-reactivity. Rather than continue to grapple with the uncertainty and inadequacy of published assays, we developed new assays for the Alexandrium species most likely to be present in Alaska. Only Alexandrium fundyense Group I and A. ostenfeldii were identified from four sampling regions from southeast Alaska to Kodiak Island, indicating that these two species are widely distributed. PCR assays for these two species were converted to quantitative (q)PCR format for use in monitoring programs. During the course of this study, we realized that a systematic evaluation of all published (~150) Alexandrium species-specific assays would be of benefit. Toward this objective, we collated published Alexandrium PCR, qPCR, and in situ hybridization assay primers and probes that targeted the small-subunit (SSU), internal transcribed spacer (ITS/5.8S), or D1-D3 large-subunit (LSU) (SSU/ITS/LSU) ribosomal DNA genes. Each individual primer or probe was screened against the GenBank database and Alexandrium gene sequence alignments constructed as part of this study. These data were used to identify a suite of species-specific Alexandrium assays that can be recommended for evaluation by the global harmful algal bloom community.

Paralytic shellfish poisoning (PSP) is a pervasive human health concern associated with subsistence, recreationally and commercially harvested Alaskan shellfish. PSP is caused by saxitoxins (STX), a family of structurally similar neurotoxins produced by the marine microalgae Alexandrium catenella (formerly A. fundyense). These toxins accumulate in filter-feeding shellfish such as clams, mussels and oysters. While PSP is commonly associated with consuming bivalves, toxic STX levels can also be found in crab viscera (crab butter). The first cases of PSP from consuming Dungeness crab viscera (Metacarcinus magister) were reported in 1992. Although this incident and others did not involve commercially harvested crab, they did impact management of the Dungeness crab fishery in Alaska. Current regulations in southeast Alaska permit the sale of whole Dungeness crab, whereas those in the Kodiak Archipelago must have their viscera removed post-harvest to prevent PSP. This study examines the impacts of STXs and current regulations on the Alaskan crab fishery, with a focus on Dungeness crab. Data on commercial landings and the value of harvested Dungeness crab and processed products showed that regulations to protect human health, combined with market forces over the past 30 years, have shifted the fishery's focus toward Dungeness crab products without viscera. The study also presents time series data on STX concentrations in Dungeness crab from 1992 to 2023, along with maps indicating collection locations and their associated toxicity levels. The same data for King crab (Paralithodes or Lithodes spp.) and Tanner (Snow) crab (Chionoecetes spp.) are included to assess the prevalence of STX in these commercially harvested species. Further, a preliminary analysis suggests regional variations in the toxicity of A. catenella strains could affect regional shellfish toxicity.

Ciguatera Fish Poisoning (CFP) is the most frequently reported seafood-toxin illness in the world. It causes substantial human health, social, and economic impacts. The illness produces a complex array of gastrointestinal, neurological and neuropsychological, and cardiovascular symptoms, which may last days, weeks, or months. This paper is a general review of CFP including the human health effects of exposure to ciguatoxins (CTXs), diagnosis, human pathophysiology of CFP, treatment, detection of CTXs in fish, epidemiology of the illness, global dimensions, prevention, future directions, and recommendations for clinicians and patients. It updates and expands upon the previous review of CFP published by Friedman et al. (2008) and addresses new insights and relevant emerging global themes such as climate and environmental change, international market issues, and socioeconomic impacts of CFP. It also provides a proposed universal case definition for CFP designed to account for the variability in symptom presentation across different geographic regions. Information that is important but unchanged since the previous review has been reiterated. This article is intended for a broad audience, including resource and fishery managers, commercial and recreational fishers, public health officials, medical professionals, and other interested parties.

An energy-dispersive X-ray fluorescence (EDXRF) analysis of nineteen obsidian source rocks from a mid-Tertiary rhyolite/perlite flow in the upper Río Bavispe basin of northeastern Sonora, Mexico solves the location of \"Sonora Unknown B\" as reported by ) for recent archaeological projects in northeastern Sonora and southeastern Arizona. This newly discovered source, called Selene, is a relatively large marekanite source consisting of a very high-silica rhyolite with regionally distinct high barium (Ba) and strontium (Sr) values, and low zirconium (Zr) elemental concentrations. The Selene nodules are relatively large compared to nodules from other northern Sonoran and Chihuahuan obsidian sources, and have excellent knapping qualities. We believe these attributes contributed to the transport, trade, and use of Selene obsidian hundreds of kilometers from the source. This is in contrast to marekanites from some other sources in northwestern Mexico, which were at most transported and used a few tens of kilometers from their sources ( ; :77).

The CENTER as part of the UNIVERSITY and a partner with the FAA’s TEST SITE is tasked with the dual role of exploring the application of Unmanned Aerial Systems (UAS) to academic and scientific research as well as evaluating the safety and proper operating practices in order to integrate unmanned aircraft into the National Air Space. An important component of this is the ability to test a wide variety of sensors and integrate them into UAS platforms quickly to respond to academic and scientific research proposals. This necessitates evaluating multiple sensors and rapidly integrating them into existing aircraft platforms. The approach taken is that of rapid prototyping utilizing 3D printing and in-house composite layups to create prototypes that can be evaluated. The ability to design a part, print it, and test it in a day or two allows the shortening of the engineering design cycle and the ability rapidly evaluate sensor integration solutions and therefore the sensors themselves. While parts can be out-sourced for final design models, it has also been determined that in-house 3D printed designs, and composite layers using 3D printed molds can be of sufficient quality for field work, depending on the application. This approach has been applied to the development of aircraft in the example of the CENTER Ptarmigan, an electric powered hexacopter which utilizes commercial-off-the-shelf components combined with custom parts, including 3D printed covers, battery cases, etc. in order to create an “open” hardware/software style system. This gives CENTER the ability to integrate sensors onto a platform without requiring vendor support to overcome proprietary, locked down systems. Examples of sensors integrated into the Ptarmigan include: 1) multiple instruments designed to sample particulate matter for volcano and wildfire plumes (optical particle, impact drum sensor, and IR technologies); 2) IR cameras for survey of arctic land/marine wildlife, volcano and wildfire footprints, and monitoring critical oil pipeline/processing infrastructure; and 3) single/multiple camera configurations to precisely measure vegetation structure, and create digital elevation models of glacial/sea ice; 4) hyperspectral camera to analyze numerous arctic environmental phenomena, such as vegetation health and regrowth after wildfires, presence of minerals in support of resource discovery, oil spill cleanup, and shoreline soil composition for coastal erosion studies. In addition, sensor/payload components for other aircraft types have been developed for fixed-wing and rotary wing aircraft, including a methane sensor, numerous gimbal components/protective casings for camera payloads. Additional UAS vehicles include the LM Stalker (wildfire monitoring) and DJI F450 (paired with unmanned ground vehicles for mine rescue operations). This approach of “open” style aircraft combined with the use of cutting edge technology to rapidly prototype and integrate sensors onto UAS has seen some numerous life success in projects undertaken by CENTER. Impacts of these have enabled great advances in our scientific research and academics. This paper will provide details of payloads/components fabricated for CENTER UAS assets supporting exciting arctic research, as well as lessons learned and efforts pushing this down to HS/MS students.