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Pfiesteria
''Pfiesteria'' is a genus of heterotrophic dinoflagellates that has been associated with harmful algal blooms and fish kills. ''Pfiesteria'' complex organisms (PCOs) were claimed to be responsible for large fish kills in the 1980s and 1990s on the coast of North Carolina and in tributaries of the Chesapeake Bay. In reaction to the toxic outbreaks, six states along the US east coast have initiated a monitoring program to allow for rapid response in the case of new outbreaks and to better understand the factors involved in ''Pfiesteria'' toxicity and outbreaks. New molecular detection methods have revealed that ''Pfiesteria'' has a worldwide distribution. Discovery and naming ''Pfiesteria'' was discovered in 1988 by North Carolina State University researchers JoAnn Burkholder and Ed Noga. The genus was named after Lois Ann Pfiester (1936–1992), a biologist who did much of the early research on dinoflagellates. Species There are two species described, ''Pfiesteria piscicida'' (fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pfiesteria Piscicida
''Pfiesteria piscicida'' is a dinoflagellate species of the genus '' Pfiesteria'' that some researchers claim is responsible for many harmful algal blooms in the 1980s and 1990s on the coast of North Carolina and Maryland. North Carolinian media in the 1990s referred to the organism as the cell from hell. It is known to populate estuaries. ''Piscicida'' means "fish-killer". Life cycles Early research suggested a very complex life cycle of ''Pfiesteria piscicida'' with up to 24 different stages, spanning from cyst to several amoeboid forms with toxic zoospores. Transformations from one stage to another depend on environmental conditions such as the availability of food. However these results have become controversial as additional research has found only a simple haplontic life cycle with no toxic amoeboid stages and amoebae present on attacked fish may represent an unrelated species of protist. Toxicity ''Pfiesteria'' presumably kills fish via releasing a toxin into the water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Predatory Dinoflagellate
Predatory dinoflagellates are predatory heterotrophic or mixotrophic alveolates that derive some or most of their nutrients from digesting other organisms. About one half of dinoflagellates lack photosynthetic pigments and specialize in consuming other eukaryotic cells, and even photosynthetic forms are often predatory. Organisms that derive their nutrition in this manner include '' Oxyrrhis marina'', which feeds phagocytically on phytoplankton, '' Polykrikos kofoidii'', which feeds on several species of red-tide and/or toxic dinoflagellates, '' Ceratium furca'', which is primarily photosynthetic but also capable of ingesting other protists such as ciliates, '' Cochlodinium polykrikoides'', which feeds on phytoplankton, ''Gambierdiscus toxicus'', which feeds on algae and produces a toxin that causes ciguatera fish poisoning when ingested, and ''Pfiesteria'' and related species such as '' Luciella masanensis'', which feed on diverse prey including fish skin and human blood cells. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pfiesteria Shumwayae
''Pseudopfiesteria shumwayae'' (formerly placed in the genus ''Pfiesteria''; see 'Taxonomy' section below) is a species of heterotrophic dinoflagellates in the genus '' Pseudopfiesteria.'' It was first characterized in North Carolina in 2000. It can acquire the ability for photosynthesis through eating green algae and retaining their chloroplasts. It can also turn predatory and toxic. Strains of ''Pseudopfiesteria shumwayae'' have been implicated in fish kills around the US east coast. ''Pseudopfiesteria shumwayae'' has been described as having a less complex life cycle than ''Pfiesteria piscicida''. Toxicity While toxic strains of ''Pseudopfiesteria shumwayae'' have been implicated in fish kills, its ability to secrete an exotoxin to kill its prey has been subject to controversy. A study published in 2002 has shown that it is capable of killing fish by direct contact and feeding on their skin through micropredation. Toxicity levels appear to depend on the strains and assays use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinoflagellate Genera
The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are mostly marine plankton, but they also are common in freshwater habitats. Their populations vary with sea surface temperature, salinity, and depth. Many dinoflagellates are photosynthetic, but a large fraction of these are in fact mixotrophic, combining photosynthesis with ingestion of prey (phagotrophy and myzocytosis). In terms of number of species, dinoflagellates are one of the largest groups of marine eukaryotes, although substantially smaller than diatoms. Some species are endosymbionts of marine animals and play an important part in the biology of coral reefs. Other dinoflagellates are unpigmented predators on other protozoa, and a few forms are parasitic (for example, ''Oodinium'' and ''Pfiesteria''). Some dinoflagellates pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinoflagellate
The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are mostly marine plankton, but they also are common in freshwater habitats. Their populations vary with sea surface temperature, salinity, and depth. Many dinoflagellates are photosynthetic, but a large fraction of these are in fact mixotrophic, combining photosynthesis with ingestion of prey (phagotrophy and myzocytosis). In terms of number of species, dinoflagellates are one of the largest groups of marine eukaryotes, although substantially smaller than diatoms. Some species are endosymbionts of marine animals and play an important part in the biology of coral reefs. Other dinoflagellates are unpigmented predators on other protozoa, and a few forms are parasitic (for example, ''Oodinium'' and ''Pfiesteria''). Some dinoflagellates pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lois Ann Pfiester
Lois Ann Pfiester (November 20, 1936 – September 28, 1992) was an American phycologist and protistologist, specializing in freshwater dinoflagellate species. Biography Pfiester received in 1965 her A.B. from Spalding University, in 1970 her M.A. from Murray State University, and in 1974 her Ph.D. in botany from Ohio State University. She joined in 1974 the faculty of the botany department of the University of Oklahoma as an assistant professor and was a full professor there in 1992 at the time of her death. She directed 4 doctoral dissertations and was the author or coauthor of over 75 journal articles. In 1978 she went to Prague for four weeks to work with the protistologist Jiří Popovský. The two colleagues identified more than 30 different stages to the life cycle of dinoflagellates of the genus ''Cystodinedria''. Pfiester was an associate editor for the ''Journal of Phycology'' from 1980 to 1988. In 1990 she was the president of the Phycological Society of America. Sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chesapeake Bay
The Chesapeake Bay ( ) is the largest estuary in the United States. The Bay is located in the Mid-Atlantic (United States), Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula (including the parts: the Eastern Shore of Maryland / Eastern Shore of Virginia and the state of Delaware) with its mouth of the Bay at the south end located between Cape Henry and Cape Charles (headland), Cape Charles. With its northern portion in Maryland and the southern part in Virginia, the Chesapeake Bay is a very important feature for the ecology and economy of those two states, as well as others surrounding within its watershed. More than 150 major rivers and streams flow into the Bay's drainage basin, which covers parts of six states (New York, Pennsylvania, Delaware, Maryland, Virginia and West Virginia) and all of District of Columbia. The Bay is approximately long from its northern headwaters in the Susquehanna River to its outlet in the Atlantic Ocea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harmful Algal Bloom
A harmful algal bloom (HAB) (or excessive algae growth) is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, mechanical damage to other organisms, or by other means. HABs are sometimes defined as only those algal blooms that produce toxins, and sometimes as any algal bloom that can result in severely lower oxygen levels in natural waters, killing organisms in marine or fresh waters. Blooms can last from a few days to many months. After the bloom dies, the microbes that decompose the dead algae use up more of the oxygen, generating a " dead zone" which can cause fish die-offs. When these zones cover a large area for an extended period of time, neither fish nor plants are able to survive. Harmful algal blooms in marine environments are often called "red tides". It is sometimes unclear what causes specific HABs as their occurrence in some locations appears to be entirely natural, while in others they appear to be a re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amoeboid
An amoeba (; less commonly spelled ameba or amœba; plural ''am(o)ebas'' or ''am(o)ebae'' ), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopods. Amoebae do not form a single taxonomic group; instead, they are found in every major lineage of eukaryotic organisms. Amoeboid cells occur not only among the protozoa, but also in fungi, algae, and animals. Microbiologists often use the terms "amoeboid" and "amoeba" interchangeably for any organism that exhibits amoeboid movement. In older classification systems, most amoebae were placed in the class or subphylum Sarcodina, a grouping of single-celled organisms that possess pseudopods or move by protoplasmic flow. However, molecular phylogenetic studies have shown that Sarcodina is not a monophyletic group whose members share common descent. Consequently, amoeboid organisms are no longer classified together in one group.Jan Pawlow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Carolina State University
North Carolina State University (NC State) is a public land-grant research university in Raleigh, North Carolina. Founded in 1887 and part of the University of North Carolina system, it is the largest university in the Carolinas. The university forms one of the corners of the Research Triangle together with Duke University in Durham and the University of North Carolina at Chapel Hill. It is classified among "R1: Doctoral Universities – Very high research activity". The North Carolina General Assembly established the North Carolina College of Agriculture and Mechanic Arts, now NC State, on March 7, 1887, originally as a land-grant college. The college underwent several name changes and officially became North Carolina State University at Raleigh in 1965. However, by longstanding convention, the "at Raleigh" portion is usually omitted. Today, NC State has an enrollment of more than 35,000 students, making it among the largest in the country. NC State has historical strengths ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myzocytosis
Myzocytosis (from Greek: myzein, (') meaning "to suck" and kytos (') meaning "container", hence referring to "cell") is a method of feeding found in some heterotrophic organisms. It is also called "cellular vampirism" as the predatory cell pierces the cell wall and/or cell membrane of the prey cell with a feeding tube, the conoid, sucks out the cellular content and digests it. Myzocytosis is found in Myzozoa and also in some species of Ciliophora (both comprise the alveolates). A classic example of myzocytosis is the feeding method of the infamous predatory ciliate, ''Didinium'', where it is often depicted devouring a hapless ''Paramecium''. The suctorian ciliates were originally thought to have fed exclusively through myzocytosis, sucking out the cytoplasm of prey via superficially drinking straw A drinking straw is a utensil that is intended to carry the contents of a beverage to one's mouth. Straws are commonly made from plastics but environmental concerns and new regulatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Warfare
Biological warfare, also known as germ warfare, is the use of biological toxins or infectious agents such as bacteria, viruses, insects, and fungi with the intent to kill, harm or incapacitate humans, animals or plants as an act of war. Biological weapons (often termed "bio-weapons", "biological threat agents", or "bio-agents") are living organisms or replicating entities ( ''i.e.'' viruses, which are not universally considered "alive"). Entomological (insect) warfare is a subtype of biological warfare. Offensive biological warfare is prohibited under customary international humanitarian law and several international treaties. In particular, the 1972 Biological Weapons Convention (BWC) bans the development, production, acquisition, transfer, stockpiling and use of biological weapons. Therefore, the use of biological agents in armed conflict is a war crime. In contrast, defensive biological research for prophylactic, protective or other peaceful purposes is not proh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
