What is Pseudo-nitzschia SPP?
Pseudo-nitzschia is a marine planktonic diatom genus that accounts for 4.4% of pennate diatoms found worldwide. Some species are capable of producing the neurotoxin domoic acid (DA), which is responsible for the neurological disorder in humans known as amnesic shellfish poisoning (ASP).
Where is Pseudo-nitzschia found?
Pseudo-nitzschia australis is a pennate diatom found in temperate and sub-tropic marine waters, such as off the coast of California and Argentina. This diatom is a Harmful Micro Algae that produces toxic effects on a variety of organisms through its production of domoic acid, a neurotoxin.
What causes Pseudo-nitzschia blooms?
The researchers concluded that the extraordinarily high populations of Pseudo-nitzschia in 2015 were related to the strength and timing of upwelling events. But the extremely high concentrations of domoic acid were probably caused by unusual ocean chemistry—specifically a low ratio of silicate to nitrate in bay waters.
What toxin does Pseudo-nitzschia fraudulenta produce?
neurotoxin domoic acid
The neurotoxin domoic acid is produced by the globally-distributed diatom genus Pseudo-nitzschia. This toxin is responsible for amnesic shellfish poisoning, which can result in illness or death in humans and regularly causes mass mortalities of marine mammals and birds.
What causes paralytic shellfish poisoning?
Causes. Paralytic shellfish poisoning is caused from the ingestion of toxin-contaminated bivalve shellfish and crustaceans. Algal blooms of dinoflagellates, usually during the warmer months of June to October, result in toxin accumulation in filter feeders such as bivalves.
What eats Karenia brevis?
brevis. Fish species through the food chain are impacted, up to and including large predatory species such as sharks, as well as species typical in human consumption.
How do you test for paralytic shellfish poisoning?
Laboratory testing for PSP in shellfish is via liquid chromatographic post-column oxidation (LC PCOX). This new test, which replaces the traditional mouse bioassay method used since the 1950s, separates fluid samples at the molecular level, thus allowing for individual toxic compounds to be identified and measured.
How is paralytic shellfish poisoning diagnosed?
Diagnosis of PSP is presumptive and based on recent ingestion of shellfish and presence of manifestations consistent with symptoms of PSP; diagnosis is confirmed by detection of paralytic shellfish toxins in a clinical specimen or food sample.
Is neurotoxic shellfish poisoning fatal?
Although not fatal to humans, neurotoxic shellfish poisoning is known to kill fish, invertebrates, seabirds, and marine mammals (e.g., manatees). It is caused by the brevetoxin family of toxins (brevetoxin + 10 related compounds9 produced by the dinoflagellate Karenia brevis (= Gymnodinium breve).
How do you treat Karenia brevis?
brevis toxin may confirm red tide intoxication, in addition to the presence of increased dinoflagellate counts in water samples. Treatment focuses on prevention of drowning. Generally, affected manatees are propped up on foam to keep their heads above water for 24 to 48 hours and closely observed.
How many species of Pseudo nitzschia are there?
Currently, 58 species are known, 28 of which have been shown to produced DA. It was originally hypothesized that only dinoflagellates could produce harmful algal toxins, but a deadly bloom of Pseudo-nitzschia occurred in 1987 in the bays of Prince Edward Island, Canada, and led to an outbreak of ASP.
What kind of cell wall does Pseudo nitzschia have?
Pseudo-nitzschia is a widely distributed genus of marine diatoms including toxic and non-toxic species. The green, photosynthetic cells of Pseudo-nitzschia have bilateral symmetry with silica cell walls called frustules.
What kind of chain forming diatom is Pseudo nitzschia?
Pseudo-nitzschia is a chain forming pennate diatom. There are many species within the genus Pseudo-nitzschia, and most are difficult to distinguish from one another with routine light microscopy. The individual cells in a chain overlap their neighbor cells at the tip.
What are the effects of Pseudo nitzschia algal blooms?
Pseudo-nitzschia species have a diverse temperature ranges allowing them to occupy variable habitats from the open ocean to coastal waters. Blooms are often associated with increased nutrients, high light levels, and warm seawater temperatures.