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Leech
Leeches are segmented parasitism, parasitic or Predation, predatory worms that comprise the Class (biology), subclass Hirudinea within the phylum Annelida. They are closely related to the Oligochaeta, oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodies that can lengthen and contract. Both groups are hermaphrodites and have a clitellum, but leeches typically differ from the oligochaetes in having suckers at both ends and in having ring markings that do not correspond with their internal segmentation. The body is muscular and relatively solid, and the coelom, the spacious body cavity found in other annelids, is reduced to small channels. The majority of leeches live in freshwater habitats, while some species can be found in terrestrial or marine environments. The best-known species, such as the medicinal leech, ''Hirudo medicinalis'', are hematophagous, attaching themselves to a host with a sucker and feeding on blood, having first secr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hirudo Medicinalis
''Hirudo medicinalis'', the European medicinal leech, is one of several species of leeches used as "medicinal leeches". Other species of ''Hirudo'' sometimes also used as medicinal leeches include '' H. orientalis'', ''H. troctina'', and '' H. verbana''. The Asian medicinal leech includes '' Hirudinaria manillensis'', and the North American medicinal leech is '' Macrobdella decora''. Morphology The general morphology of medicinal leeches follows that of most other leeches. Fully mature adults can be up to 20 cm in length, and are green, brown, or greenish-brown with a darker tone on the dorsal side and a lighter ventral side. The dorsal side also has a thin red stripe. These organisms have two suckers, one at each end, called the anterior and posterior suckers. The posterior is used mainly for leverage, whereas the anterior sucker, consisting of the jaw and teeth, is where the feeding takes place. Medicinal leeches have three jaws (tripartite) that resemble saws, on which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annelid
The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments. The Annelids are bilaterally symmetrical, triploblastic, coelomate, invertebrate organisms. They also have parapodia for locomotion. Most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species. Cladistic research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded as sub-groups of polychae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euhirudinea
Euhirudinea, the true leeches, are an infraclass of the Hirudinea. Taxonomy These clitellate annelids are of somewhat unclear relationships; namely the relationships of Hirudinea with oligochaetes are in need of revision. It may be that the presumed sister taxon of the Euhirudinea, the Acanthobdellidea, turns out to be more distantly related, as was already the case with the Branchiobdellida. Thus, eventually Euhirudinea might become a junior synonym of Hirudinea. True leeches are subdivided into two groups, the Arhynchobdellida or Arhynchobdellae (proboscisless leeches), and the Rhynchobdellida or Rhynchobdellae (jawless leeches). Note that the lack of jaws is a plesiomorphy, while the presence of a proboscis is an apomorphy – not all Arhynchobdellida have jaws, but all Rhynchobdellida have a proboscis. The best-known leech species, ''Hirudo medicinalis ''Hirudo medicinalis'', the European medicinal leech, is one of several species of leeches used as "medicinal leeches ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bloodletting
Bloodletting (or blood-letting) is the withdrawal of blood from a patient to prevent or cure illness and disease. Bloodletting, whether by a physician or by leeches, was based on an ancient system of medicine in which blood and other bodily fluids were regarded as "humours" that had to remain in proper balance to maintain health. It is claimed to have been the most common medical practice performed by surgeons from antiquity until the late 19th century, a span of over 2,000 years. In Europe, the practice continued to be relatively common until the end of the 19th century.B.) Anderson, Julie, Emm Barnes, and Enna Shackleton. "The Art of Medicine: Over 2,000 Years of Images and Imagination ardcover" The Art of Medicine: Over 2, 000 Years of Images and Imagination: Julie Anderson, Emm Barnes, Emma Shackleton: : The Ilex Press Limited, 2013. The practice has now been abandoned by modern-style medicine for all except a few very specific medical conditions. In the overwhe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haementeria Ghilianii
''Haementeria ghilianii'', the giant Amazon leech, is one of the world's largest species of leeches. It can grow to 450 mm (17.7 in) in length and 100 mm (3.9 in) in width. As adults, these leeches are a greyish-brown colour, as opposed to juveniles, which do not have a uniform colour, but rather, a noncontinuous stripe of colour, and patched colouring. They live from the Guianas to the Amazon. The leech produces the anticoagulant protease hementin Hementin is an anticoagulant protease (fibrinogen lytic enzyme) from the salivary glands of the giant Amazon leech ('' Haementeria ghilianii''). Hementin is a calcium-dependent protease with a molecular weight of 80-120 kDa, and it contains 39 amino ... from its salivary glands. It was thought to be extinct from the 1890s until the 1970s, when specimens were rediscovered in French Guiana by Dr Roy Sawyer. One of these leeches, dubbed Grandma Moses, founded a successful breeding colony at UC Berkeley. Article with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossiphoniidae
Glossiphoniidae are a family of freshwater proboscis-bearing leeches. These leeches are generally flattened, and have a poorly defined anterior sucker. Most suck the blood of freshwater vertebrates like amphibians, crocodilians and aquatic turtles, but some feed on invertebrates like oligochaetes and freshwater snails instead. Although they prefer other hosts, blood-feeding species will opportunistically feed from humans. There is considerable interest in the symbiotic bacteria that at least some glossiphoniids house in specialized organs called bacteriomes. The bacteria are thought to provide the leeches with nutrients that are scarce or absent from their regular diets. '' Haementeria'' as well as '' Placobdelloides'' have Enterobacteriaceae symbionts, while '' Placobdella'' harbours peculiar and independently derived alphaproteobacteria. Systematics and taxonomy The relationships between members of Glossiphoniidae are not completely understood. Some sources divide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helobdella
''Helobdella'' is a genus of leeches in the family Glossiphoniidae, the freshwater jawless leeches. They occur worldwide.Kutschera, U., et al. (2013)Description of a new leech species from North America, ''Helobdella austinensis'' n. sp.(Hirudinea: Glossiphoniidae), with observations on its feeding behaviour.''Zoosyst Evol'' 89(2) 239-46. These are small, flat leeches which do not feed on blood.Siddall, M. E. and E. Borda. (2003)Phylogeny and revision of the leech genus ''Helobdella'' (Glossiphoniidae) based on mitochondrial gene sequences and morphological data and a special consideration of the ''triserialis'' complex.''Zoologica Scripta'' 32(1), 23-33. Several species in this genus are used as model organisms in the study of developmental biology. It has been difficult to define species in this genus without DNA analysis. Like other leeches in this family, some ''Helobdella'' species are polymorphic, coming in different colors and patterns. On the other hand, some uniformly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haemadipsa Zeylanica Japonica
''Haemadipsa'' is a genus of leeches, with members commonly known as ''jawed land leeches''. These annelids are known from subtropical and tropical regions around the Indian and Pacific Ocean. Well-known ''Haemadipsa'' are for example the Indian Leech (''Haemadipsa sylvestris'') and the yamabiru or Japanese Mountain Leech (''Haemadipsa zeylanica''). Members of the genus feed on blood. They are troublesome to humans and animals especially because their bites result in prolonged bleeding. Species in the genus ''Haemadipsa'' *'' Haemadipsa cavatuses'' *''Haemadipsa cochiniana'' *''Haemadipsa crenata'' *''Haemadipsa hainana'' *'' Haemadipsa interrupta'' *''Haemadipsa japonica'' *''Haemadipsa limuna'' *''Haemadipsa moorei'' *''Haemadipsa montana'' *''Haemadipsa ornata'' *'' Haemadipsa picta'' (Tiger leech) *''Haemadipsa rjukjuana'' *''Haemadipsa sumatrana'' *''Haemadipsa sylvestris'' (Indian leech) *''Haemadipsa trimaculosa'' *''Haemadipsa zeylanica ''Haemadipsa'' is a genus of leech ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clitellum
The clitellum is a thickened glandular and non-segmented section of the body wall near the head in earthworms and leeches, that secretes a viscid sac in which eggs are stored. It is located near the anterior end of the body, between the fourteenth and seventeenth segments. The number of the segments to where the clitellum begins and the number of segments that make up the clitellum are important for identifying earthworms. In microdrile earthworms, the clitellum has only one layer, resulting in a smaller quantity of eggs than that of the megadrile earthworms, which have larger multi-layered clitellum that have special cells that secrete albumin into the worms' egg sac. The clitellum is part of the reproductive system of clitellates, a subgroup of annelids which contains oligochaetes (earthworms) and hirudineans (leeches). The clitellum is a thick, saddle-like ring found in the epidermis (skin) of the worm, usually with a light-colored pigment. To form a cocoon for its eggs, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hirudin
Hirudin is a naturally occurring peptide in the salivary glands of blood-sucking leeches (such as '' Hirudo medicinalis'') that has a blood anticoagulant property. This is fundamental for the leeches’ habit of feeding on blood, since it keeps a host's blood flowing after the worm's initial puncture of the skin. Hirudin (MEROPS I14.001) belongs to a superfamily (MEROPS IM) of protease inhibitors that also includes haemadin (MEROPS I14.002) and antistasin (MEROPS I15). Structure During his years in Birmingham and Edinburgh, John Berry Haycraft had been actively engaged in research and published papers on the coagulation of blood, and in 1884, he discovered that the leech secreted a powerful anticoagulant, which he named hirudin, although it was not isolated until the 1950s, nor its structure fully determined until 1976. Full length hirudin is made up of 65 amino acids. These amino acids are organized into a compact N-terminal domain containing three disulfide bonds and a C-t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hematophagous
Hematophagy (sometimes spelled haematophagy or hematophagia) is the practice by certain animals of feeding on blood (from the Greek words αἷμα ' "blood" and φαγεῖν ' "to eat"). Since blood is a fluid tissue rich in nutritious proteins and lipids that can be taken without great effort, hematophagy is a preferred form of feeding for many small animals, such as worms and arthropods. Some intestinal nematodes, such as Ancylostomatids, feed on blood extracted from the capillaries of the gut, and about 75 percent of all species of leeches (e.g., ''Hirudo medicinalis'') are hematophagous. The spider Evarcha culicivora feeds indirectly on vertebrate blood by specializing on blood-filled female mosquitoes as their preferred prey. Some fish, such as lampreys and candirus, and mammals, especially the vampire bats, and birds, such as the vampire finches, hood mockingbirds, the Tristan thrush, and oxpeckers also practise hematophagy. Mechanism and evolution These h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anticoagulant
Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where they help keep the bite area unclotted long enough for the animal to obtain some blood. As a class of medications, anticoagulants are used in therapy for thrombotic disorders. Oral anticoagulants (OACs) are taken by many people in pill or tablet form, and various intravenous anticoagulant dosage forms are used in hospitals. Some anticoagulants are used in medical equipment, such as sample tubes, blood transfusion bags, heart–lung machines, and dialysis equipment. One of the first anticoagulants, warfarin, was initially approved as a rodenticide. Anticoagulants are closely related to antiplatelet drugs and thrombolytic drugs by manipulating the various pathways of blood coagulation. Specifically, antiplatelet drugs inhibit pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
