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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] |
Heterotroph
A heterotroph (; ) is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but not producers. Living organisms that are heterotrophic include all animals and fungi, some bacteria and protists, and many parasitic plants. The term heterotroph arose in microbiology in 1946 as part of a classification of microorganisms based on their type of nutrition. The term is now used in many fields, such as ecology in describing the food chain. Heterotrophs may be subdivided according to their energy source. If the heterotroph uses chemical energy, it is a chemoheterotroph (e.g., humans and mushrooms). If it uses light for energy, then it is a photoheterotroph (e.g., green non-sulfur bacteria). Heterotrophs represent one of the two mechanisms of nutrition (trophic levels), the other being autotrophs (''auto'' = self, ''troph'' = ... [...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] |
James City County
James City County is a county located in the Commonwealth of Virginia. As of the 2020 census, the population was 78,254. Although politically separate from the county, the county seat is the adjacent independent city of Williamsburg. Located on the Virginia Peninsula, James City County is included in the Virginia Beach-Norfolk-Newport News, VA- NC Metropolitan Statistical Area. It is often associated with Williamsburg, an independent city, and Jamestown which is within the county. First settled by the English colonists in 1607 at Jamestown in the Virginia Colony, the County was formally created in 1634 as James City Shire by order of King Charles I. James City County is considered one of only five original shires of Virginia to still be extant today in essentially the same political form. The Jamestown 2007 celebration marked the 400th anniversary of the founding of Jamestown. Tourism is a major part of the region's economy, as is high technology. The College of William a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
York River (Virginia)
The York River is a navigable estuary, approximately long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed April 1, 2011 in eastern Virginia in the United States. It ranges in width from at its head to near its mouth on the west side of Chesapeake Bay. Its watershed drains an area of the Atlantic coastal plain, coastal plain of Virginia north and east of Richmond, Virginia, Richmond. Its banks were inhabited by indigenous peoples of North America, indigenous peoples for thousands of years. In 2003 evidence was found of the likely site of Werowocomoco, one of two capitals used by the paramount chief Powhatan before 1609. The site was inhabited since 1200 as a major village. Enormously important in later U.S. history, the river was also the scene of early settlements of the Colony of Virginia, Virginia Colony. It was the site of significant events and battles in both the American Revolutionary War and the American C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algal Bloom
An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompasses many types of aquatic photosynthetic organisms, both macroscopic multicellular organisms like seaweed and microscopic unicellular organisms like cyanobacteria. ''Algal bloom'' commonly refers to the rapid growth of microscopic unicellular algae, not macroscopic algae. An example of a macroscopic algal bloom is a kelp forest. Algal blooms are the result of a nutrient, like nitrogen or phosphorus from various sources (for example fertilizer runoff or other forms of nutrient pollution), entering the aquatic system and causing excessive growth of algae. An algal bloom affects the whole ecosystem. Consequences range from the benign feeding of higher trophic levels to more harmful effects like blocking sunlight from reaching other organ ... [...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] |
Exotoxin
An exotoxin is a toxin secreted by bacteria. An exotoxin can cause damage to the host by destroying cells or disrupting normal cellular metabolism. They are highly potent and can cause major damage to the host. Exotoxins may be secreted, or, similar to endotoxins, may be released during lysis of the cell. Gram negative pathogens may secrete outer membrane vesicles containing lipopolysaccharide endotoxin and some virulence proteins in the bounding membrane along with some other toxins as intra-vesicular contents, thus adding a previously unforeseen dimension to the well-known eukaryote process of membrane vesicle trafficking, which is quite active at the host–pathogen interface. They may exert their effect locally or produce systemic effects. Well-known exotoxins include: botulinum toxin produced by ''Clostridium botulinum''; '' Corynebacterium diphtheriae'' toxin, produced during life-threatening symptoms of diphtheria; tetanospasmin produced by ''Clostridium tetani''. The toxi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Kills
The term fish kill, known also as fish die-off, refers to a localized die-off of fish populations which may also be associated with more generalized mortality of aquatic life.University of Florida. Gainesville, FL (2005) ''Plant Management in Florida's Waters.'' The most common cause is reduced oxygen in the water, which in turn may be due to factors such as drought, algae bloom, overpopulation, or a sustained increase in water temperature. Infectious diseases and parasites can also lead to fish kill. Toxicity is a real but far less common cause of fish kill. Fish kills are often the first visible signs of environmental stress and are usually investigated as a matter of urgency by environmental agencies to determine the cause of the kill. Many fish species have a relatively low tolerance of variations in environmental conditions and their death is often a potent indicator of problems in their environment that may be affecting other animals and plants and may have a direct impact ... [...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] |
Predator
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the host) and parasitoidism (which always does, eventually). It is distinct from scavenging on dead prey, though many predators also scavenge; it overlaps with herbivory, as seed predators and destructive frugivores are predators. Predators may actively search for or pursue prey or wait for it, often concealed. When prey is detected, the predator assesses whether to attack it. This may involve ambush or pursuit predation, sometimes after stalking the prey. If the attack is successful, the predator kills the prey, removes any inedible parts like the shell or spines, and eats it. Predators are adapted and often highly specialized for hunting, with acute senses such as vision, hearing, or smell. Many predatory animals, both vertebrate and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroplast
A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water in the cells. The ATP and NADPH is then used to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in unicellular algae, up to 100 in plants like ''Arabidopsis'' and wheat. A chloroplast is characterized by its two membranes and a high concentration of chlorophyll. Other plastid types, such as the leucoplast and the chromoplast, contain little chlorophyll and do not carry out photosynthesis. Chloroplasts are highly dynamic—they circulat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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