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Bioaccumulate
Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance faster than it can be lost or eliminated by catabolism and excretion. Thus, the longer the biological half-life of a toxic substance, the greater the risk of chronic poisoning, even if environmental levels of the toxin are not very high. Bioaccumulation, for example in fish, can be predicted by models. Hypothesis for molecular size cutoff criteria for use as bioaccumulation potential indicators are not supported by data. Biotransformation can strongly modify bioaccumulation of chemicals in an organism. Toxicity induced by metals is associated with bioaccumulation and biomagnification. Storage or uptake of a metal faster than it is metabolized and excreted leads to the accumulation of that metal. The presence of various chemicals and harmful substances in the environment can be analyzed and assessed with a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioconcentration
In aquatic toxicology, bioconcentration is the accumulation of a water-borne chemical substance in an organism exposed to the water. There are several ways in which to measure and assess bioaccumulation and bioconcentration. These include: octanol-water partition coefficients (KOW), bioconcentration factors (BCF), bioaccumulation factors (BAF) and biota-sediment accumulation factor (BSAF). Each of these can be calculated using either empirical data or measurements, as well as from mathematical models. One of these mathematical models is a fugacity-based BCF model developed by Don Mackay. Bioconcentration factor can also be expressed as the ratio of the concentration of a chemical in an organism to the concentration of the chemical in the surrounding environment. The BCF is a measure of the extent of chemical sharing between an organism and the surrounding environment. In surface water, the BCF is the ratio of a chemical's concentration in an organism to the chemical's aqu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pesticides
Pesticides are substances that are used to pest control, control pest (organism), pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all pesticide use globally. Most pesticides are used as plant protection products (also known as crop protection products), which in general protect plants from weeds, fungi, or insects. In general, a pesticide is a Chemical substance, chemical or biological agent (such as a virus, bacterium, or entomopathogenic fungus, fungus) that deters, incapacitates, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens, weeds, mollusca, molluscs, birds, mammals, fish, nematodes (roundworms), and microbes that destroy property, cause nuisance, spread disease, or are disease Vector (epidemiology), vectors. Along with these benefits, pesticides also have drawbacks, such as Pesticide poisoning, potent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poisoning
Poisoning is the harmful effect which occurs when Toxicity, toxic substances are introduced into the body. The term "poisoning" is a derivative of poison, a term describing any chemical substance that may harm or kill a living organism upon ingestion. Poisoning can be brought on by swallowing, inhaling, injecting or absorbing toxins through the skin. Toxicology is the practice and study of symptoms, mechanisms, diagnoses, and treatments correlated to poisoning. Levels of Exposure When a living organism is introduced to a poison, the Signs and symptoms, symptoms that follow successful contact develop in Dose–response relationship, close relation to the degree of exposure. Acute exposure Acute toxicity, Acute toxicity/poisoning consists of a living organism being harmfully exposed to poison once or more times during a brief period, with symptoms manifesting within 14 days since administration. Chronic exposure Chronic toxicity, Chronic toxicity/poisoning involves a li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomagnification
Biomagnification, also known as bioamplification or biological magnification, is the increase in concentration of a substance, e.g a pesticide, in the tissue (biology), tissues of organisms at successively higher levels in a food chain. This increase can occur as a result of: * Persistence – where the substance cannot be broken down by environmental processes. * Food chain bioenergetics, energetics – where the substance's concentration increases progressively as it moves up a food chain. * Low or non-existent rate of internal degradation or excretion of the substance – mainly due to water-insolubility. Biological magnification often refers to the process whereby substances such as pesticides or heavy metals work their way into lakes, rivers and the ocean, and then move up the food chain in progressively greater concentrations as they are incorporated into the diet of aquatic organisms such as zooplankton, which in turn are eaten perhaps by fish, which then may be eaten by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manduca Sexta
''Manduca sexta'' is a moth of the family Sphingidae present through much of the Americas. The species was first described by Carl Linnaeus in his 1763 ''Centuria Insectorum''. Commonly known as the Carolina sphinx moth and the tobacco hawk moth (as adults) and the tobacco hornworm and the Goliath worm (as larvae), it is closely related to and often confused with the very similar tomato hornworm (''Manduca quinquemaculata''); the larvae of both feed on the foliage of various plants of the family Solanaceae. The larvae of these species can be distinguished by their lateral markings: Tomato hornworms have eight V-shaped white markings with no borders; tobacco hornworms have seven white diagonal lines with a black border. Additionally, tobacco hornworms have red horns, while tomato hornworms have dark blue or black horns. A mnemonic to remember the markings is tobacco hornworms have straight white lines like cigarettes, while tomato hornworms have V-shaped markings (as in "vine-ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitamin A
Vitamin A is a fat-soluble vitamin that is an essential nutrient. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinyl esters, and several provitamin (precursor) carotenoids, most notably Β-Carotene, β-carotene (''beta''-carotene). Vitamin A has multiple functions: growth during embryo development, maintaining the immune system, and healthy vision. For aiding vision specifically, it combines with the protein opsin to form rhodopsin, the light-absorbing molecule necessary for both low-light (scotopic vision) and color vision. Vitamin A occurs as two principal forms in foods: A) retinoids, found in Animal source foods, animal-sourced foods, either as retinol or bound to a fatty acid to become a retinyl ester, and B) the carotenoids Α-Carotene, α-carotene (''alpha''-carotene), β-carotene, Γ-Carotene, γ-carotene (''gamma''-carotene), and the xanthophyll beta-cryptoxanthin (all of which contain β-ionone rings) that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tobacco
Tobacco is the common name of several plants in the genus '' Nicotiana'' of the family Solanaceae, and the general term for any product prepared from the cured leaves of these plants. More than 70 species of tobacco are known, but the chief commercial crop is ''N. tabacum''. The more potent variant ''N. rustica'' is also used in some countries. Dried tobacco leaves are mainly used for smoking in cigarettes and cigars, as well as pipes and shishas. They can also be consumed as snuff, chewing tobacco, dipping tobacco, and snus. Tobacco contains the highly addictive stimulant alkaloid nicotine as well as harmala alkaloids. Tobacco use is a cause or risk factor for many deadly diseases, especially those affecting the heart, liver, and lungs, as well as many cancers. In 2008, the World Health Organization named tobacco use as the world's single greatest preventable cause of death. Etymology The English word 'tobacco' originates from the Spanish word ''taba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicotine
Nicotine is a natural product, naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and ''Duboisia hopwoodii'') and is widely used recreational drug use, recreationally as a stimulant and anxiolytic. As a pharmaceutical drug, it is used for smoking cessation to relieve drug withdrawal, withdrawal symptoms. Nicotine acts as a receptor agonist at most nicotinic acetylcholine receptors (nAChRs), except at two nicotinic receptor subunits (nAChRα9 and nAChRα10) where it acts as a receptor antagonist. Nicotine constitutes approximately 0.6–3.0% of the dry weight of tobacco. Nicotine is also present at Parts-per notation, ppb concentrations in edible plants in the family Solanaceae, including potatoes, tomatoes, and eggplants, though sources disagree on whether this has any biological significance to human consumers. It functions as an plant defense against herbivory, antiherbivore toxin; consequently, nicotine was widely used as an insecti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead
Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable nuclide, stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its Amphoterism, amphoteric nature; lead and lead oxides react with acids and base (chemistry), bases, and it tends to form covalent bonds. Lead compounds, Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liver
The liver is a major metabolic organ (anatomy), organ exclusively found in vertebrates, which performs many essential biological Function (biology), functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of various proteins and various other Biochemistry, biochemicals necessary for digestion and growth. In humans, it is located in the quadrants and regions of abdomen, right upper quadrant of the abdomen, below the thoracic diaphragm, diaphragm and mostly shielded by the lower right rib cage. Its other metabolic roles include carbohydrate metabolism, the production of a number of hormones, conversion and storage of nutrients such as glucose and glycogen, and the decomposition of red blood cells. Anatomical and medical terminology often use the prefix List of medical roots, suffixes and prefixes#H, ''hepat-'' from ἡπατο-, from the Greek language, Greek word for liver, such as hepatology, and hepatitis The liver is also an accessory digestive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnivore
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ... whose nutrition and energy requirements are met by eating, consumption of animal tissue (biology), tissues (mainly muscle, adipose tissue, fat and other soft tissues) as food, whether through predation or scavenger, scavenging. Nomenclature Mammal order The technical term for mammals in the order (biology), order Carnivora is ''carnivoran'', and they are so-named because most member species in the group have a carnivorous diet, but the similarity of the name of the order and the name of the diet causes confusion. Many but not all carnivorans are meat eaters; a few, such as the fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteogenesis
Osteoblasts (from the Greek language, Greek combining forms for "bone", ὀστέο-, ''osteo-'' and βλαστάνω, ''blastanō'' "germinate") are cell (biology), cells with a single Cell nucleus, nucleus that synthesize bone. However, in the process of bone formation, osteoblasts function in groups of connected cells. Individual cells cannot make bone. A group of organized osteoblasts together with the bone made by a unit of cells is usually called the osteon. Osteoblasts are specialized, terminally differentiated products of mesenchymal stem cells. They synthesize dense, crosslinked collagen and specialized proteins in much smaller quantities, including osteocalcin and osteopontin, which compose the organic matrix of bone. In organized groups of disconnected cells, osteoblasts produce hydroxyapatite, the bone mineral, that is deposited in a highly regulated manner, into the inorganic matrix forming a strong and dense mineralized tissues, mineralized tissue, the mineralized ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
