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Mollusc Shell
The mollusc (or mollusk) shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes. Not all shelled molluscs live in the sea; many live on the land and in freshwater. The ancestral mollusc is thought to have had a shell, but this has subsequently been lost or reduced on some families, such as the squid, octopus, and some smaller groups such as the caudofoveata and neomeniomorpha, solenogastres. Today, over 100,000 living species bear a shell; there is some dispute as to whether these shell-bearing molluscs form a monophyletic group (conchifera) or whether shell-less molluscs are interleaved into their family tree. Malacology, the scientific study of molluscs as living organisms, has a branch devoted to the study of shells, and this is called conchology—although these terms used to be, and to a minor extent still are, used interchange ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berlin Naturkundemuseum Muscheln
Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population within city limits, highest population within its city limits of any city in the European Union. The city is also one of the states of Germany, being the List of German states by area, third smallest state in the country by area. Berlin is surrounded by the state of Brandenburg, and Brandenburg's capital Potsdam is nearby. The urban area of Berlin has a population of over 4.6 million and is therefore the most populous urban area in Germany. The Berlin/Brandenburg Metropolitan Region, Berlin-Brandenburg capital region has around 6.2 million inhabitants and is Germany's second-largest metropolitan region after the Rhine-Ruhr region, as well as the List of EU metropolitan areas by GDP, fifth-biggest metropolitan region by GDP in the European Union. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Carbonate
Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skeletons and pearls. Materials containing much calcium carbonate or resembling it are described as calcareous. Calcium carbonate is the active ingredient in agricultural lime and is produced when calcium ions in hard water react with carbonate ions to form limescale. It has medical use as a calcium supplement or as an antacid, but excessive consumption can be hazardous and cause hypercalcemia and digestive issues. Chemistry Calcium carbonate shares the typical properties of other carbonates. Notably, it: *reacts with acids, releasing carbonic acid which quickly disintegrates into carbon dioxide and water: : *releases carbon dioxide upon heating, called a thermal decomposition reaction, or calcination (to above 840 °C in the case of ), t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusc Shells
The mollusc (or mollusk) shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes. Not all shelled molluscs live in the sea; many live on the land and in freshwater. The ancestral mollusc is thought to have had a shell, but this has subsequently been lost or reduced on some families, such as the squid, octopus, and some smaller groups such as the caudofoveata and solenogastres. Today, over 100,000 living species bear a shell; there is some dispute as to whether these shell-bearing molluscs form a monophyletic group (conchifera) or whether shell-less molluscs are interleaved into their family tree. Malacology, the scientific study of molluscs as living organisms, has a branch devoted to the study of shells, and this is called conchology—although these terms used to be, and to a minor extent still are, used interchangeably, even by sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diatom
A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's Biomass (ecology), biomass. They generate about 20 to 50 percent of the oxygen produced on the planet each year, take in over 6.7 billion tonnes of silicon each year from the waters in which they live, and constitute nearly half of the organic material found in the oceans. The Protist shell, shells of dead diatoms are a significant component of marine sediment, and the entire Amazon basin is fertilized annually by 27 million tons of diatom shell dust transported by transatlantic winds from the African Sahara, much of it from the Bodélé Depression, which was once made up of a system of fresh-water lakes. Diatoms are unicellular organisms: they occur either as solitary cells or in Colony (biology), colonies, which can take the shape of ribb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lustrin A
Lustrin A is an insoluble protein used in the production of a nacreous layer in bivalve molluscs. It contributes to the properties of the nacreous layer, imparting resistance to cracking and elasticity. This is accomplished by its structure; it consists of many spring-like units which can expand when the shell is under extensional pressure. Its structure is similar to that of proteins involved in ''silica'' deposition in diatom A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ...s. It consists of 1428 amino acid residues. Its molecular weight is estimated to be 142 kDa. Its terminus consists of a protease inhibitor, which contributes to its longevity in the molluscan shell matrix. References {{Reflist Molluscan proteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C-type Lectin
A C-type lectin (CLEC) is a type of carbohydrate-binding protein known as a lectin. The C-type designation is from their requirement for calcium for binding. Proteins that contain C-type lectin domains have a diverse range of functions including cell-cell adhesion, immune response to pathogens and apoptosis. Classification Drickamer ''et al.'' classified C-type lectins into 7 subgroups (I to VII) based on the order of the various protein domains in each protein. This classification was subsequently updated in 2002, leading to seven additional groups (VIII to XIV). Most recently, three further subgroups were added (XV to XVII). CLECs include: * CLEC1A, CLEC1B * CLEC2A, CLEC2B, CD69 (CLEC2C), CLEC2D, CLEC2L * CLEC3A, CLEC3B * CLEC4A, CLEC4C, CLEC4D, CLEC4E, CLEC4F, CLEC4G, ASGR1 (CLEC4H1), ASGR2 (CLEC4H2), FCER2 (CLEC4J), CD207 (CLEC4K), CD209 (CLEC4L), CLEC4M * CLEC5A * CLEC6A * CLEC7A * OLR1 (CLEC8A) * CLEC9A * CLEC10A * CLEC11A * CLEC12A, CLEC12B * CD302 (CLEC13A), LY75 (CLEC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hox Gene
Hox genes, a subset of homeobox, homeobox genes, are a gene cluster, group of related genes that Evolutionary developmental biology, specify regions of the body plan of an embryo along the craniocaudal axis, head-tail axis of animals. Hox proteins encode and specify the characteristics of 'position', ensuring that the correct structures form in the correct places of the body. For example, Hox genes in insects specify which appendages form on a segment (for example, legs, antennae, and wings in fruit flies), and Hox genes in vertebrates specify the types and shape of vertebrae that will form. In segmented animals, Hox proteins thus confer segmental or positional identity, but do not form the actual segments themselves. Studies on Hox genes in ciliated larvae have shown they are only expressed in future adult tissues. In larvae with gradual metamorphosis the Hox genes are activated in tissues of the larval body, generally in the trunk region, that will be maintained through metamorp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decapentaplegic
''Decapentaplegic'' (''Dpp'') is a key morphogen involved in the development of the fruit fly ''Drosophila melanogaster'' and is the first validated secreted morphogen. It is known to be necessary for the correct patterning and development of the early ''Drosophila'' embryo and the fifteen imaginal discs, which are tissues that will become limbs and other organs and structures in the adult fly. It has also been suggested that ''Dpp'' plays a role in regulating the growth and size of tissues. Flies with mutations in decapentaplegic fail to form these structures correctly, hence the name (''decapenta''-, fifteen; -''plegic'', paralysis). ''Dpp'' is the ''Drosophila'' homolog of the vertebrate bone morphogenetic proteins (BMPs), which are members of the transforming growth factor beta superfamily, TGF-β superfamily, a class of proteins that are often associated with their own specific signaling pathway. Studies of ''Dpp'' in ''Drosophila'' have led to greater understanding of the func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Engrailed (gene)
''engrailed'' is a homeodomain transcription factor involved in many aspects of multicellular development. First known for its role in arthropod embryological development, working in consort with the Hox genes, ''engrailed'' has been found to be important in other areas of development. It has been identified in many bilaterians, including the arthropods, vertebrates, echinoderms, molluscs, nematodes, brachiopods, and polychaetes. It acts as a "selector" gene, conferring a specific identity to defined areas of the body, and co-ordinating the expression of downstream genes. Protein ''engrailed (en)'' encodes the homeodomain-containing transcription factor protein Engrailed. Homologous Engrailed proteins are found in a diversity of organisms. When expressed in the ectoderm, ''engrailed'' is involved in the production of skeletal material. ''engrailed'', or genes with very similar sequences, are found in all bilaterian animals. ''engrailed'' plays a number of crucial roles in bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acta Zoologica
''Acta Zoologica'' is a peer-reviewed scientific journal published by Wiley-Blackwell on behalf of the Royal Swedish Academy of Sciences and the Royal Danish Academy of Sciences and Letters. It is one of the world's leading zoological journals and focuses on animal development, structure, and function, including physiological organization. It primarily publishes original research papers, but occasionally also publishes review articles. Increasingly, it has concentrated on animal development, with emphasis on the functional, comparative, and phylogenetic aspects. The editor-in-chief is Lennart Olsson (University of Jena). History The journal was established in 1920 with Nils Holmgren serving as the first editor. In 1980, the journal absorbed ''Zoon : a journal of zoology'' which ran 1973–1979 and was a continuation of the publication Zoologiska Bidrag från Uppsala (1911-1972). Abstracting and indexing The journal is abstracted and indexed in: According to the ''Journal C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropods
Gastropods (), commonly known as slugs and snails, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and from the land. There are many thousands of species of sea snails and slugs, as well as freshwater snails, freshwater limpets, land snails and slugs. The class Gastropoda is a diverse and highly successful class of mollusks within the phylum Mollusca. It contains a vast total of named species, second only to the insects in overall number. The fossil history of this class goes back to the Late Cambrian. , 721 families of gastropods are known, of which 245 are extinct and appear only in the fossil record, while 476 are currently extant with or without a fossil record. Gastropoda (previously known as univalves and sometimes spelled "Gasteropoda") are a major part of the phylum Mollusca, and are the most highly diversified class in the phylum, with 65,00 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautilus (genus)
''Nautilus'' is a marine cephalopod genus in the Mollusca, mollusk family (biology), family Nautilidae. Species in this genus differ significantly, Morphology (biology), morphologically, from the two nautilus species in the adjacent sister-taxon ''Allonautilus''. The oldest fossils of the genus are known from the Late Eocene Hoko River Formation, in Washington State and from Late-Eocene to Early Oligocene sediments in Kazakhstan. The oldest fossils of the modern species ''Nautilus pompilius'' are from Early Pleistocene sediments off the coast of Luzon in the Philippines. The commonly used term 'nautilus' usually refers to any of the surviving members of ''Nautilidae'', and more specifically to the ''Nautilus pompilius'' species. The entire family of ''Nautilidae'', including all species in the genera ''Nautilus'' and ''Allonautilus'', is listed on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Various authors claim th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
