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Perennial Ryegrass Staggers
Perennial ryegrass staggers is poisoning by peramine, lolitrem B, and other toxins that are contained in perennial ryegrass (''Lolium perenne''), and produced by the endophyte fungus '' Neotyphodium lolii'' which can be present in all parts of the grass plant, but tends to be concentrated in the lower part of the leaf sheaths, the flower stalks and seeds. This condition can affect horses, cattle, sheep, farmed deer and llamas. It regularly occurs in New Zealand and is known spasmodically from Australia, North and South America, and Europe. Ecology Perennial ryegrass staggers is caused by the ingestion of grass that is infected by the endophyte fungus ''Epichloë festucae'' var ''lolli'', and this fungus produces a variety of toxins such as peramine, a pyrrolopyrazine alkaloid, and lolitrem B, an indole-diterpene compound. There is no external sign when perennial ryegrass is infected by this fungus. The Argentine stem weevil (''Listronotus bonariensis'') feeds on perennial ryegras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diterpene
Diterpenes are a class of chemical compounds composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being a primary intermediate. Diterpenes form the basis for biologically important compounds such as retinol, retinal, and phytol. They are known to be antimicrobial and antiinflammatory. Structures As with most terpenes a huge number of potential structures exists, which may be broadly divided according to the number of rings present. Biosynthesis Diterpenes are derived from the addition of one IPP unit to FPP to form geranylgeranyl-pyrophosphate (GGPP). From GGPP, structural diversity is achieved mainly by two classes of enzymes; the diterpene synthases and cytochromes P450. Several diterpenes are produced by plants and cyanobacteria. GGPP is also the precursor for the synthesis of the phytane by the action of the enzyme geranylger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Fungal Diseases
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motility, able to move, can Sexual reproduction, reproduce sexually, and go through an ontogenetic stage in which their body consists of a hollow sphere of Cell (biology), cells, the blastula, during Embryogenesis, embryonic development. Over 1.5 million Extant taxon, living animal species have been Species description, described—of which around 1 million are Insecta, insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from to . They have Ecology, complex interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology. Most living animal species are in Bilateria, a clade whose members have a Symmetry in biology#Bilate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rumen
The rumen, also known as a paunch, is the largest stomach compartment in ruminants and the larger part of the reticulorumen, which is the first chamber in the alimentary canal of ruminant animals. The rumen's microbial favoring environment allows it to serve as the primary site for microbial fermentation of ingested feed. The smaller part of the reticulorumen is the reticulum, which is fully continuous with the rumen, but differs from it with regard to the texture of its lining. Brief anatomy The rumen is composed of several muscular sacs, the cranial sac, ventral sac, ventral blindsac, and reticulum. The lining of the rumen wall is covered in small fingerlike projections called papillae, which are flattened, approximately 5mm in length and 3mm wide in cattle. The reticulum is lined with ridges that form a hexagonal honeycomb pattern. The ridges are approximately 0.1–0.2mm wide and are raised 5mm above the reticulum wall. The hexagons in the reticulum are approximately 2â ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetanus
Tetanus, also known as lockjaw, is a bacterial infection caused by ''Clostridium tetani'', and is characterized by muscle spasms. In the most common type, the spasms begin in the jaw and then progress to the rest of the body. Each spasm usually lasts a few minutes. Spasms occur frequently for three to four weeks. Some spasms may be severe enough to fracture bones. Other symptoms of tetanus may include fever, sweating, headache, trouble swallowing, high blood pressure, and a fast heart rate. Onset of symptoms is typically three to twenty-one days following infection. Recovery may take months. About ten percent of cases prove to be fatal. ''C. tetani'' is commonly found in soil, saliva, dust, and manure. The bacteria generally enter through a break in the skin such as a cut or puncture wound by a contaminated object. They produce toxins that interfere with normal muscle contractions. Diagnosis is based on the presenting signs and symptoms. The disease does not spread between pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nystagmus
Nystagmus is a condition of involuntary (or voluntary, in some cases) eye movement. Infants can be born with it but more commonly acquire it in infancy or later in life. In many cases it may result in reduced or limited vision. Due to the involuntary movement of the eye, it has been called "dancing eyes". In normal eyesight, while the head rotates about an axis, distant visual images are sustained by rotating eyes in the opposite direction of the respective axis. The semicircular canals in the vestibule of the ear sense angular acceleration, and send signals to the nuclei for eye movement in the brain. From here, a signal is relayed to the extraocular muscles to allow one's gaze to fix on an object as the head moves. Nystagmus occurs when the semicircular canals are stimulated (e.g., by means of the caloric test, or by disease) while the head is stationary. The direction of ocular movement is related to the semicircular canal that is being stimulated. There are two key form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tiller (botany)
A tiller is a shoot that arises from the base of a grass plant. The term refers to all shoots that grow after the initial parent shoot grows from a seed. Tillers are segmented, each segment possessing its own two-part leaf. They are involved in vegetative propagation and, in some cases, also seed production. "Tillering" refers to the production of side shoots and is a property possessed by many species in the grass family. This enables them to produce multiple stems (tillers) starting from the initial single seedling. This ensures the formation of dense tufts and multiple seed heads. Tillering rates are heavily influenced by soil water quantity. When soil moisture is low, grasses tend to develop more sparse and deep root systems (as opposed to dense, lateral systems). Thus, in dry soils, tillering is inhibited: the lateral nature of tillering is not supported by lateral root growth. See also *Crown (botany) The crown of a plant refers to the total of an individual plant's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutualism (biology)
Mutualism describes the ecological interaction between two or more species where each species has a net benefit. Mutualism is a common type of ecological interaction. Prominent examples include most vascular plants engaged in mutualistic interactions with mycorrhizae, flowering plants being pollinated by animals, vascular plants being dispersed by animals, and corals with zooxanthellae, among many others. Mutualism can be contrasted with interspecific competition, in which each species experiences ''reduced'' fitness, and exploitation, or parasitism, in which one species benefits at the expense of the other. The term ''mutualism'' was introduced by Pierre-Joseph van Beneden in his 1876 book ''Animal Parasites and Messmates'' to mean "mutual aid among species". Mutualism is often conflated with two other types of ecological phenomena: cooperation and symbiosis. Cooperation most commonly refers to increases in fitness through within-species (intraspecific) interactions, althoug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Listronotus Bonariensis
''Listronotus bonariensis'' is a species of weevil that is native to South America and is commonly known as the Argentine stem weevil. It is a pest of grasses and cereals, with the larvae being more destructive than the adult insects. It has spread to Australia and New Zealand, where it is regarded as a pest species. Description The Argentine stem weevil is a small grey insect up to long, with a waxy covering. Soil particles adhere to this wax, and while the insect remains stationary, which it often does, this makes it well-camouflaged and difficult to spot. The larvae are cream-coloured grubs with brownish heads. Distribution The Argentine stem weevil is native to South America where it is present in Brazil, Uruguay, Argentina, Bolivia and Chile. In these countries it is not considered to be economically important. It has spread to Australia and New Zealand, in both of which countries it is regarded as a pest species. In New Zealand, it is considered to be the most important in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indole
Indole is an aromatic heterocyclic organic compound with the formula C8 H7 N. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered pyrrole ring. Indole is widely distributed in the natural environment and can be produced by a variety of bacteria. As an intercellular signal molecule, indole regulates various aspects of bacterial physiology, including spore formation, plasmid stability, resistance to drugs, biofilm formation, and virulence. The amino acid tryptophan is an indole derivative and the precursor of the neurotransmitter serotonin. General properties and occurrence Indole is a solid at room temperature. It occurs naturally in human feces and has an intense fecal odor. At very low concentrations, however, it has a flowery smell, and is a constituent of many perfumes. It also occurs in coal tar. The corresponding substituent is called indolyl. Indole undergoes electrophilic substitution, mainly at position 3 (see diagra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lolitrem B
Lolitrem B is one of many toxins produced by a fungus called ''Epichloë festucae'' var. ''lolii''), which grows in '' Lolium perenne'' (perennial ryegrass). The fungus is symbiotic with the ryegrass; it doesn't harm the plant, and the toxins it produces kill insects that feed on ryegrass. Lolitrem B is one of these toxins, but it is also harmful to mammals. The shoots and flowers of infected ryegrass have especially high concentrations of lolitrem B, and when livestock eat too much of them, they get perennial ryegrass staggers. At low doses the animals have tremors, and at higher doses they stagger, and at higher yet doses the animals become paralyzed and die. The blood pressure of the animals also goes up. The effect of the lolitrem B comes on slowly and fades out slowly, as it is stored in fat after the ryegrass is eaten. The condition is especially common in New Zealand and Australia, and plant breeders there have been trying to develop strains of fungus that produce to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Llama
The llama (; ) (''Lama glama'') is a domesticated South American camelid, widely used as a List of meat animals, meat and pack animal by Inca empire, Andean cultures since the Pre-Columbian era. Llamas are social animals and live with others as a herd. Their wool is soft and contains only a small amount of lanolin. Llamas can learn simple tasks after a few repetitions. When using a pack, they can carry about 25 to 30% of their body weight for 8 to 13 kilometre, km (5–8 miles). The name ''llama'' (in the past also spelled "lama" or "glama") was adopted by European colonization of the Americas, European settlers from Indigenous people in Peru, native Peruvians. The ancestors of llamas are thought to have originated from the Great Plains of North America about 40 million years ago, and subsequently migrated to South America about three million years ago during the Great American Interchange. By the end of the last Quaternary glaciation, ice age (10,000–12,000 years ago), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
