Algal Toxins
Algal toxins are toxic substances produced by certain species of algae. When these toxins accumulate in water, they can pose serious health risks to humans and animals if ingested through contaminated seafood or water. Algal toxins can cause a range of health issues, including neurological and gastrointestinal symptoms, and can be particularly harmful to the liver and nervous system.
6 Key excerpts on "Algal Toxins"
eBook - ePubHandbook of Marine Microalgae
Biotechnology Advances
- Se-Kwon Kim(Author)
- 2015(Publication Date)
- Academic Press(Publisher)
...Algal Toxins Algal Toxins, or red-tide toxins, are naturally derived and toxic emerging contaminants produced during HABs in surface waters (Imai et al., 2006 ; Prince et al., 2008 ; Castle and Rodgers, 2009 ; Yates and Rogers, 2011). The occurrence, abundance, and geographical distribution of toxin-producing algae or cyanobacterial blooms have substantially increased during the last few decades because of increased anthropogenic input of organic matter pollution and nutrients and because of global warming (Phlips et al., 2004 ; Yan and Zhou, 2004 ; Luckas et al., 2005 ; McCarthy et al., 2007 ; Mostofa and Sakugawa, 2009). 8. Impacts of Algal Toxins Algal Toxins produced during algal blooms in surface waters are responsible for physiological, ecological, and environmental adverse effects, including the following: • Deterioration of water quality with high eutrophication (Howarth, 2008 ; Castle and Rodgers, 2009) • Depletion of dissolved oxygen below the pycnocline (Jeong et al., 2008) • Loss of seagrasses and benthos (Bricelj and Lonsdale, 1997) • Loss of phytoplankton competitor motility (Prince et al., 2008) • Inhibition of enzymes and photosynthesis (Prince et al., 2008) • Cell and membrane damage (Prince et al., 2008) • Mortality of fish, coral reefs, livestock, and wildlife (Bricelj and Lonsdale, 1997 ; Imai and Kimura, 2008 ; Southard et al., 2010 ; Yates and Rogers, 2011) • Shellfish or finfish poisoning caused by neurotoxic compounds (brevetoxins), produced by blooms of red-tide dinoflagellates such as Karenia brevis or other algae (Backer et al., 2005 ; Moore et al., 2008) • Illness or even death of higher organisms or humans, associated with consumption of contaminated fish,...
eBook - ePubMarine Macro- and Microalgae
An Overview
- F. Xavier Malcata, Isabel Sousa Pinto, A. Catarina Guedes, F. Xavier Malcata, Isabel Sousa Pinto, A. Catarina Guedes(Authors)
- 2018(Publication Date)
- CRC Press(Publisher)
...Occasional and sudden proliferation of dinoflagellates in marine environments has led to a phenomenon called Harmful Algal Blooms (HABs); they are likely to produce toxins that can negatively distress marine life, especially via poisoning fish and shellfish (Hallegraeff 2003). Moreover, HABs and associated toxin production can impact human health if direct consumption of contaminated shellfish (or fish) takes place afterwards; and disturb economic activities, with unfavorable implications upon fisheries or tourism (Anderson 1995; Smayda 1997). Despite associated risks, the aforementioned toxins possess remarkable biotechnological features— thus justifying an effort to still seek more toxin biocompounds, and eventually produce them at large scale. Unfortunately, only a meager quantity of those molecules has reached the market—and still with several limitations. The restricted availability thereof from natural sources (Haefner 2003), and the limited and unfeasible routes for chemical synthesis, or the scarce advances in genetic engineering of dinoflagellates (Gallardo-Rodríguez et al. 2012a) have greatly hampered development of toxin-derived leads for pharmacores. There are at present many difficulties to grow dinoflagellates in laboratory cultures (using conventional reactors), and several attempts have failed to obtain the intended compounds (Wynn et al. 2010; Gallardo-Rodríguez et al. 2012a). Nevertheless, production of such potent bioactive compounds in relatively high quantities (and in a safe mode) is an important issue before pharmacological studies and pre-clinical trials can be developed (Glaser and Mayer 2009; Zittelli et al. 2013). The production of toxin by dinoflagellate cultures in photobioreactors is still the preferred approach—despite the underlying constraints regarding fastidious growth and extreme sensitiveness to shear stress (Gallardo-Rodríguez et al. 2009)...
eBook - ePubGlobal Climate Change and Human Health
From Science to Practice
- Jay Lemery, Kim Knowlton, Cecilia Sorensen, Jay Lemery, Kim Knowlton, Cecilia Sorensen(Authors)
- 2021(Publication Date)
- Jossey-Bass(Publisher)
...This toxicity is largely due to the ability of such toxins to inhibit enzymes and ion channels, leading to organ failure in a short time (e.g., Metcalf and Codd 2012). Acute effects attributed to cyanobacterial and Algal Toxins have been observed with mortality of a variety of animals such as fish, dogs, cattle, and sheep (Codd et al. 2005). In addition to direct human health effects, the death of large numbers of animals can have a negative impact on local economies and industries such as tourism and fisheries (Hoagland and Scatasta 2006). As acute exposures to cyanobacterial and Algal Toxins have increasingly been reported, public understanding of the risks has increased, as has the introduction of legislation and guidelines to help protect people from future toxin exposures (Codd et al. 2005; Metcalf and Codd 2012). In addition to the acute health effects of algal and cyanobacterial toxins, research is now focused on the long-term effects of these toxic exposures. Many algal and cyanobacterial toxins are increasingly thought to be carcinogens and tumor promoters (Nishiwaki-Matsushima et al. 1992 ; Ohta et al. 1994 ; Zegura, Straser, and Filipic 2011). Higher incidences of primary liver cancer have been attributed to exposure to microcystin in China (Ueno et al. 1996) and Eastern Europe (Svircev et al. 2013) and may occur through the inhibition of protein phosphatases, which is also a mode of action of okadaic acid (Metcalf, Bell, and Codd 2001), a primary cause of marine DSP toxicity events. Other tumor promoters include palytoxin, teliocidin, and aplysiatoxin (Fujiki and Sugimura 1987). Long-term exposure to BMAA is now considered to be a possible causative agent of human neurodegenerative diseases (Cox et al. 2016). With ASP, exposure to domoic acid can result in permanent loss of short-term memory, which can have drastic chronic effects for people who have been exposed to sufficient doses of this marine toxin (Perl et al. 1990)...
- Julian White, Jurg Meier(Authors)
- 2017(Publication Date)
- CRC Press(Publisher)
...These compounds comprise a wide variety of chemical structures ranging from simple molecules such as amines to more complex molecules like alkaloids, terpenes, steroids, peptides or even proteins. Among them some of the most lethal toxins are found: saxitoxin, tetrodotoxin, ciguatoxin, palytoxin, the conotoxins or sea snake toxins. Although considerable progress in marine chemistry led to the discovery of many new compounds with peculiar structures, only a small fraction of marine organisms have been investigated. These metabolites serve many purposes in the marine ecosystems; they are used for prey capture or for defense, cause antibiosis to prevent microbial infection or overgrowth by competing organisms; they may also have signal functions like pheromones, by deterring and repelling predators or by attracting sexual or symbiotic partners 4. However, the role these compounds play in the complex interactions of marine organisms is still poorly understood. Until recent years research was mainly motivated by finding new compounds useful for medical purposes or was initiated when these compounds interfered with marine food production and caused serious public health problems. III. POISONOUS MARINE ANIMALS In the marine environment poisonous animals are more abundant than commonly anticipated. Their noxious or toxic metabolites act only when ingested, because these animals lack tools or weapons to apply these compounds parenterally. This limits the chances and danger of poisoning, since seafood is a selection of animals, which are normally free of poisons, toxins or harmful substances. Nevertheless these animals are part of the marine food chain and may accumulate noxious compounds from man-made sea pollution (metals, industrial or agricultural chemicals etc.), but may also contain naturally occurring metabolites such as saxitoxin and ciguatoxin. Many marine animals are known to be poisonous and are avoided and not harvested as sea food; e.g...
eBook - ePub- Dongyou Liu, Dongyou Liu(Authors)
- 2018(Publication Date)
- CRC Press(Publisher)
...Integrative monitoring of marine and freshwater harmful algae in Washington State for public health protection. Toxins (Basel) 2015;7:1206–34. 90. Al-Tebrineh J, Mihali TK, Pomati F, Neilan BA. Detection of saxitoxin-producing cyanobacteria and Anabaena circinalis in environmental water blooms by quantitative PCR. Appl Environ Microbiol 2010;76:7836–42. 91. Murray SA, Wiese M, Stuken A et al. sxtA -based quantitative molecular assay to identify saxitoxin-producing harmful algal blooms in marine waters. Appl Environ Microbiol 2011;77:7050–7. 92. Anderson DM, Cembella AD, Hallegraeff GM. Progress in understanding harmful algal blooms: Paradigm shifts and new technologies for research, monitoring, and management. Ann Rev Mar Sci 2012;4:143–76. 93. Van Dolah F. Marine Algal Toxins: Origins, health effects, and their increased occurrence. Environ Health Perspect 2000;108:133–41. 94. Hallegraeff G. Transport of toxic dinoflagellates via ships’ ballast water: Bioeconomic risk assessment and efficacy of possible ballast water management strategies. Mar Ecol Prog Ser 1998;168:297–309. 95. Hallegaeff G. Ocean climate change, phytoplankton community responses, and harmful algal blooms: A formidable predictive challenge. J Phycol 2010;46:220–35. 96. Wells ML, Trainer VL, Smayda TJ et al. Harmful algal blooms and climate change: Learning from the past and present to forecast the future. Harmful Algae 2015;49:68–93. 97. Vale P. Complex profiles of hydrophobic paralytic shellfish poisoning compounds in Gymnodinium catenatum identified by liquid chromatography with fluorescence detection and mass spectrometry. J Chromatogr A 2008;1195:85–93....
- Ramesh C Gupta(Author)
- 2015(Publication Date)
- Academic Press(Publisher)
...Colonies are often large enough to be seen with the naked eye and, when numerous, may change the color of the water or form scums at the water surface. Dense proliferations of cyanobacteria are referred to as algal blooms. When blooms have the potential to cause harmful effects, they are called harmful algal blooms (HABs). The incidence of HABs is increasing in most regions and is usually linked to excess nutrient inflow into surface water from agricultural and industrial sources (Paerl et al., 2001 ; de Figueiredo et al., 2004 ; Hudnell, 2010 ; Gkelis and Zaoutsos, 2014). Several genera of cyanobacteria are able to produce toxins (Briand et al., 2003). The production of toxins is influenced by genetic and environmental factors. Cyanobacteria known to have the genetic potential to produce toxins do not always do so or may not produce toxins at concentrations that are high enough to result in a significant poisoning risk. Certain environmental factors, including nutrient concentrations, water temperature, and pH, may play a role in triggering toxin production. The critical parameter values that trigger toxin production are, however, not fully known or predictable. Toxin production is generally more common during warm weather and abundant sunlight but can occur at any time of the year (Downing et al., 2001 ; Kanoshina et al., 2003 ; Graham et al., 2004 ; Dodds et al., 2009). Toxin production during HABs can be extremely high. For example, a HAB formed by microcystin-LR-producing Microcystis aeruginosa in a Kansas lake in 2011, produced toxin concentrations in the water of 126,000 ng/mL (van der Merwe et al., 2012). Such concentrations are highly significant considering that hepatotoxic effects in humans are possible after ingestion of 100 mL of water containing 20 ng/mL microcystin-LR (WHO, 2003)...
