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Bioluminescent Molluscs
Bioluminescence is the emission of light during a chemiluminescence reaction by living organisms. Bioluminescence occurs in multifarious organisms ranging from marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some bioluminescent bacteria, dinoflagellates and terrestrial arthropods such as fireflies. In some animals, the light is bacteriogenic, produced by symbiotic bacteria such as those from the genus '' Vibrio''; in others, it is autogenic, produced by the animals themselves. In most cases, the principal chemical reaction in bioluminescence involves the reaction of a substrate called luciferin and an enzyme, called luciferase. Because these are generic names, luciferins and luciferases are often distinguished by the species or group, e.g. firefly luciferin or cypridina luciferin. In all characterized cases, the enzyme catalyzes the oxidation of the luciferin resulting in excited state oxyluciferin, which is the light emitter of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photinus Pyralis Firefly Glowing
Photinus (Greek: Φωτεινός; died 376) was a Christianity, Christian bishop of Sirmium in Pannonia Secunda (today the town Sremska Mitrovica in Serbia), best known for denying the incarnation of Christ, thus being considered a heresiarch by both the Catholic and Orthodox Churches. His name became synonymous in later literature for someone asserting that Christ was not God. His teachings are mentioned by various ancient authors, like Ambrosiaster (Pseudo-Ambrose), Hilary of Poitiers, Socrates Scholasticus, Sozomen, Ambrose of Milan, Augustine of Hippo, John Cassian, Sulpicius Severus, Jerome, Vigilius of Thapsus and many others. None of his writings are extant; his views must be reconstructed through his critics. Life Photinus grew up in Ankara, Ancyra in Galatia, where he was a student and later a deacon of bishop Marcellus of Ancyra, Marcellus. Marcellus, in later life a staunch opponent of Arianism, was excommunicated and deposed in 336 but rehabilitated by the Synod of Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vargulin
Vargulin, also called Cypridinid luciferin, Cypridina luciferin, or Vargula luciferin, is the luciferin found in the ostracod '' Cypridina hilgendorfii'', also named '' Vargula hilgendorfii''. These bottom dwelling ostracods emit a light stream into water when disturbed presumably to deter predation. Vargulin is also used by the midshipman fish, ''Porichthys''. History A partial extraction procedure was developed in 1935 which involved reacting the compound with benzoyl chloride to allow it to be separated from the water-soluble components. The compound was first isolated and purified to crystals by Osamu Shimomura. The structure of the compound was confirmed some years later. Feeding experiments suggest that the compound is synthesized in the animal from three amino-acids: tryptophan, isoleucine, and arginine. Biochemistry Vargulin is oxidized by the Vargula luciferase, a 62 kDa enzyme, to produce blue light at 462 nm (max emission, detected with a 425 to 525 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionary History Of Life
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as ''Ga'', for '' gigaannum'') and evidence suggests that life emerged prior to 3.7 Ga. The similarities among all known present-day species indicate that they have diverged through the process of evolution from a common ancestor. The earliest clear evidence of life comes from biogenic carbon signatures and stromatolite fossils discovered in 3.7 billion-year-old metasedimentary rocks from western Greenland. In 2015, possible "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia. There is further evidence of possibly the oldest forms of life in the form of fossilized microorganisms in hydrothermal vent precipitates from the Nuvvuagittuq Belt, that may have lived as early as 4.28 billion years ago, not long after the oceans formed 4.4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylum
In biology, a phylum (; : phyla) is a level of classification, or taxonomic rank, that is below Kingdom (biology), kingdom and above Class (biology), class. Traditionally, in botany the term division (taxonomy), division has been used instead of phylum, although the International Code of Nomenclature for algae, fungi, and plants accepts the terms as equivalent. Depending on definitions, the animal kingdom Animalia contains about 31 phyla, the plant kingdom Plantae contains about 14 phyla, and the fungus kingdom Fungi contains about eight phyla. Current research in phylogenetics is uncovering the relationships among phyla within larger clades like Ecdysozoa and Embryophyta. General description The term phylum was coined in 1866 by Ernst Haeckel from the Greek (, "race, stock"), related to (, "tribe, clan"). Haeckel noted that species constantly evolved into new species that seemed to retain few consistent features among themselves and therefore few features that distinguishe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coelenterazine
Coelenterazine is a luciferin, a molecule that emits light after reaction with oxygen, found in many aquatic organisms across eight phyla. It is the substrate of many luciferases such as '' Renilla reniformis'' luciferase (Rluc), ''Gaussia'' luciferase (Gluc), and photoproteins, including aequorin, and obelin. All these proteins catalyze the oxidation of this substance, a reaction catalogued EC 1.13.12.5. History Coelenterazine was simultaneously isolated and characterized by two groups studying the luminescent organisms sea pansy ('' Renilla reniformis'') and the cnidarian ''Aequorea victoria'', respectively. Both groups independently discovered that the same compound was used in both luminescent systems. The molecule was named after the now-obsolete phylum coelenterata. Likewise, the two main metabolites – coelenteramide and coelenteramine – were named after their respective functional groups. While coelenterazine was first discovered in ''Aequorea victoria'', it wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution
Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. The process of evolution has given rise to biodiversity at every level of biological organisation. The scientific theory of evolution by natural selection was conceived independently by two British naturalists, Charles Darwin and Alfred Russel Wallace, in the mid-19th century as an explanation for why organisms are adapted to their physical and biological environments. The theory was first set out in detail in Darwin's book ''On the Origin of Species''. Evolution by natural selection is established by observable facts about living organisms: (1) more offspring are often produced than can possibly survive; (2) phenotypic variatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adenosine Triphosphate
Adenosine triphosphate (ATP) is a nucleoside triphosphate that provides energy to drive and support many processes in living cell (biology), cells, such as muscle contraction, nerve impulse propagation, and chemical synthesis. Found in all known forms of life, it is often referred to as the "molecular unit of currency" for intracellular energy transfer. When consumed in a Metabolism, metabolic process, ATP converts either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP). Other processes regenerate ATP. It is also a Precursor (chemistry), precursor to DNA and RNA, and is used as a coenzyme. An average adult human processes around 50 kilograms (about 100 mole (unit), moles) daily. From the perspective of biochemistry, ATP is classified as a nucleoside triphosphate, which indicates that it consists of three components: a nitrogenous base (adenine), the sugar ribose, and the Polyphosphate, triphosphate. Structure ATP consists of three parts: a sugar, an amine base ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium
Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic table), it occurs naturally only in combination with other elements and almost always has an oxidation state of +2. It reacts readily with air to form a thin Passivation (chemistry), passivation coating of magnesium oxide that inhibits further corrosion of the metal. The free metal burns with a brilliant-white light. The metal is obtained mainly by electrolysis of magnesium Salt (chemistry), salts obtained from brine. It is less dense than aluminium and is used primarily as a component in strong and lightweight magnesium alloy, alloys that contain aluminium. In the cosmos, magnesium is produced in large, aging stars by the sequential addition of three Helium nucleus, helium nuclei to a carbon nucleus. When such stars explo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium
Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossils of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name comes from Latin ''calx'' " lime", which was obtained from heating limestone. Some calcium compounds were known to the ancients, though their chemistry was unknown until the seventeenth century. Pure calcium was isolated in 1808 via electrolysis of its oxide by Humphry Davy, who named the element. Calcium compounds are widely used in many industries: in foods and pharmaceuticals for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cofactor (biochemistry)
A cofactor is a non-protein chemical compound or metallic ion that is required for an enzyme's role as a catalyst (a catalyst is a substance that increases the rate of a chemical reaction). Cofactors can be considered "helper molecules" that assist in biochemical transformations. The rates at which these happen are characterized in an area of study called enzyme kinetics. Cofactors typically differ from ligands in that they often derive their function by remaining bound. Cofactors can be classified into two types: inorganic ions and complex organic molecules called coenzymes. Coenzymes are mostly derived from vitamins and other organic essential nutrients in small amounts. (Some scientists limit the use of the term "cofactor" for inorganic substances; both types are included here.) Coenzymes are further divided into two types. The first is called a " prosthetic group", which consists of a coenzyme that is tightly (or even covalently and, therefore, permanently) bound to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Peroxides
In organic chemistry, organic peroxides are organic compounds containing the peroxide functional group (). If the R′ is hydrogen, the compounds are called hydroperoxides, which are discussed in that article. The O−O bond of peroxides easily breaks, producing free radicals of the form (the dot represents an unpaired electron). Thus, organic peroxides are useful as radical initiator, initiators for some types of polymerization, such as the Acrylic resin, acrylic, unsaturated polyester, and vinyl ester resins used in glass-reinforced plastics. methyl ethyl ketone peroxide, MEKP and benzoyl peroxide are commonly used for this purpose. However, the same property also means that organic peroxides can explosively combust. Organic peroxides, like their inorganic counterparts, are often powerful bleaching agents. Types of organic peroxides Organic peroxides are classified (i) by the presence or absence of a hydroxyl () terminus and (ii) by the presence of alkyl vs acyl substituents. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ground State
The ground state of a quantum-mechanical system is its stationary state of lowest energy; the energy of the ground state is known as the zero-point energy of the system. An excited state is any state with energy greater than the ground state. In quantum field theory, the ground state is usually called the vacuum. If more than one ground state exists, they are said to be degenerate. Many systems have degenerate ground states. Degeneracy occurs whenever there exists a unitary operator that acts non-trivially on a ground state and commutes with the Hamiltonian of the system. According to the third law of thermodynamics, a system at absolute zero temperature exists in its ground state; thus, its entropy is determined by the degeneracy of the ground state. Many systems, such as a perfect crystal lattice, have a unique ground state and therefore have zero entropy at absolute zero. It is also possible for the highest excited state to have absolute zero temperature for sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
