Apoptosis - Apoptosis Apoptosis is the process of programmed cell death, the deliberate suicide of a cell in a multicellular organism for the greater good of the whole individual. In contrast to necrosis, which is a form of cell death that results from acute tissue injury, apoptosis is carried out in an ordered process that generally confers advantages during an organism's life cycle. For example, the differentiation of human fingers requires the cells in between the fingers to initiate apoptosis so that the fingers can separate. As will be explained further on, the way the apoptotic process is executed facilitates the safe disposal of cell corpses and fragments. The fact that apoptosis has been the subject of increasing attention and research efforts was highlighted by the award of.
January 14 - their American tour, at the Winterland Ballroom in San Francisco. 1984 - Ray Mancini defeats Bobby Chacon by a knockout in three to retain his WBA boxing world Lightweight title in Reno. 1985 - Martina Navratilova wins her 100th tennis tournament. 1990 - The Simpsons debuts on FOX as a regular series with the episode "Bart the Genius". 1993 - David Letterman announces he was moving his television talk show from NBC to CBS. 1994 - President of the United States Bill Clinton and Russian President Boris Yeltsin sign the Kremlin accords which stop the preprogrammed aiming of nuclear missiles to targets and also provide for the dismantling of the nuclear arsenal in the Ukraine. 1996 - Jorge Sampaio is elected president of Portugal. 1998 - Researchers in Dallas, Texas present.
Immune system - pathway activates C1,C4,C2,C3,C5 and finally C6 to C9, which forms the membrane attack complex. Complement binding will result in cytolysis, chemotaxis, opsonization and inflammation. Last but not least, Interferon α and β are important for resistance to viral infection. Adaptive immune system The adaptive immune system, which is much better understood than the innate immune system, is based on immune cells called leukocytes (or white blood cells) that are produced by stem cells in the bone marrow. The immune system can be divided into two parts. Many species, including mammals, have the following type: The humoral immune system, which acts against bacteria and viruses in the body liquids (such as blood). Its primary means of action are immunoglobulins, also called antibodies, which are produced by B cells (B means they develop.
Integrin - Integration of the cell into the surrounding tissue by cell-cell-interaction adhesive interaction Embryonal development Tumor development Apoptosis Connection between intracellular and extracellular scaffolding Among the ligands of integrins are fibronectin and collagen, both part of the extracellular matrix. Ligand binding leads to clustering (cross-connection) of the multivalent components of the integrin to a functional protein complex. Integrins have no intrinsic kinase activity, but associate kinases (for example, focal adhesion kinase, FAK) on the cytoplasmic side of the membrane..
Ecdysone - steroid hormone facilitating the ecdysis (the molt) of insect by inducing apoptosis, the programmed cell death, in certain tissue. It works inhibiting apoptosis inhibitors and activating cell death activators. Ecdysone also plays a role in the transformation from prepupa to pupa and adult differentiation..
Taxol - hyper-stabilizes their structure. This destroys the cell's ability to use its cytoskeleton in a flexible manner. Specifically, Taxol binds to the tubulin protein of microtubules and locks them in place. The resulting microtubule/taxol complex does not have the ability to disassemble. This adversely affects cell function because the shortening and lengthening of microtubules (termed dynamic instability) is necessary for their function as a transportation highway for the cell. Chromosomes, for example, rely upon this property of microtubules during mitosis. Further research has indicated that Taxol induces programmed cell death (apoptosis) in cancer cells by binding to an apoptosis stopping protein called Bcl-2 (B-cell Leukemia 2) and thus arresting its function. One common characteristic of most cancer cells is their rapid rate of cell division. In order to accommodate this, the cytoskeleton.
1998 - The Lunar Prospector spacecraft is launched into orbit around the Moon and later found evidence for frozen water on the moon's surface. January 8 - Ramzi Yousef is sentenced to life in prison for planning the World Trade Center bombing. January 8 - Cosmologists announce that the expansion rate of the universe is increasing. January 12 - 19 European nations agree to forbid human cloning. January 14 - Researchers in Dallas, Texas present findings about an enzyme the slows aging and cell death (apoptosis). January 15 - The stalker of Howard Stern, Lance Carvin, is sentenced to 2 1/2 years for threatening to kill Stern and his family. January 16 - NASA announces that John Glenn will return to space when Space Shuttle Discovery blasts off in October 1998. January 17.
1998 in science - - The CIH Virus is discovered in Taiwan. The first working 2-qubit nuclear magnetic resonance computer is demonstrated at the University of California, Berkeley. Geology February 4 - An earthquake measuring 6.1 on the Richter Scale in northeast Afghanistan kills more than 5,000. March 14 - An earthquake measuring 6.9 on the Richter scale hits southeastern Iran. May 30 - A 6.6 magnitude earthquake hits northern Afghanistan killing up to 5,000. July 17 - A tsunami triggered by an undersea earthquake destroys 10 villages in Papua New Guinea killing an estimated 1,500, leaving 2,000 more unaccounted for and thousands more homeless. Mathematics Luca Cardelli and Andrew D. Gordon develop ambient calculus. Thomas Hales (almost certainly) proves the Kepler conjecture. Medicine January 14 - Researchers in Dallas, Texas present findings about an.
Caenorhabditis elegans - only a few days. C. elegans are used as a model organism. They have the advantage of being cheap and easy to maintain in the laboratory. C. elegans have been especially useful for studying cellular differentiation, and was the first animal to have its genome completely sequenced. The C. elegans genome contains more than 19,000 genes and approximately 100 million base pairs. This organism is the subject of a proposal which involves cataloguing its glycome. It has the advantage of being a multicellular eukaryotic organism which is simple enough to be studied in great detail. The developmental fate of all of its 959 somatic cells has been mapped out, which are left from the original 1090 cells, after 131 are eliminated by apoptosis. In addition, C. elegans is one of the.
Cancer - pylori, also induce carcinogenesis by a process of chronic inflammation. Finally, damage by free radicals, which are a natural by-product of oxygen metabolism, can cause mutations in the DNA. For most of the cancers, it cannot be told which event was the initial cause. However, with molecular biology, it is possible to characterize the mutations within a tumor, and to a certain extent predict its behavior. For example, about half of the tumors are deficient in the tumor suppressor gene p53, also known as "the guardian of the genome". This is associated with poor prospects for the patient, since those tumor cells are unlikely to go into apoptosis (programmed cell death) after they are damaged by therapy. There are more mutations that make a tumor more malignant. Telomerase mutations enable a.
Caspase - enzymes that can cleave other proteins. Caspases are essential in cellss for apoptosis, the programmed cell death in development and cancer prevention. Caspases initiate apoptosis by cleaving inactive pro-forms of other caspases, thus activating them. These caspases, in turn, start the apoptotic process by cleaving pro-forms of other enzymes. The initiation of that cascade reaction is usually blocked by caspase inhibitors. Induction of apoptosis thus means overexpression of the initial caspases, overcoming the inhibition..
Calcium in biology - internal Ca storages) represent the most important sign for the whole cell machinery. Ca2+ entering the cell causes the specific action of this cell, whatever this action is: secretory cells release vesicles with their secretion, muscle cells contract, synapses go into processes of synaptic plasticity etc. The same Ca2+ ions can, however, bring damage to cells if there are too many of them (for example in a case of overexcitation in neural circuits). This may even cause cell apoptosis. See also: Ca-binding proteins.
Chemotherapy - Types of drugs 1.2 Resistance 1.3 Administration 1.4 Delivery 1.5 Side-effects 1.6 Experimental techniques 1.7 References Cancer chemotherapy Mutations of normal cellss creates cancerous tumours which can grow out of control. Broadly, chemotheraputic drugs work by selectively targeting fast-dividing cells. As these drugs cause damage to cells they are termed cytotoxic. Some drugs cause cells to commit apoptosis (effectively cell suicide), but chemotheraputic drugs all block some essential feature of the cell division process which makes cells unable to divide. Unfortunately, scientists have yet to be able to locate specific features of cancerous cells that would make them uniquely targetable. This means that other fast dividing cells such those responsible for hair growth are also affected. However by chance some drugs seem to affect cells from different tissues more intensely than.
Tumor suppressor gene - are essential for the continuing of the cell cycle. If these genes are not expressed, the cell cycle will not continue, effectively inhibiting cell division. Coupling the cell cycle to DNA damage. As long as there is damaged DNA in the cell, it should not divide. If the damage can be repaired, the cell cycle can continue. If the damage can not be repaired, the cell should initiate apoptosis, the programmed cell death, to remove the threat it poses for the greater good of the organism. The first tumor suppressor protein discovered was the pRb protein in human retinoblastoma. An important tumor suppressor is the p53 gene. See also : Cancer -- signal transduction.
Tumor - and do not seed metastases, but may locally grow to great size. See also : Apoptosis -- Oncogene -- Tumor suppressor gene -- Carcinoma -- Sarcoma -- Lymphoma -- Leukemia.
Ras - signal pathways that control such processes as cytoskeletal integrity, proliferation, cell adhesion, apoptosis, and cell migration. Ras and ras related proteins, are often deregulated in cancers, leading to various effects, that leads to increased invasion and metastasis, and decreased apoptosis. RAS is also an abbreviation for the Russian Academy of Science "Ras" is also a record label for recorded music, especially Reggae..
Phosphorylation - off by phosphorylation and dephosphorylation. Phosphorylation is catalyzed by various specific protein kinases, whereas phosphatases dephosphorylate. Regulation of protein activity is very important in cells. For example, the p53 tumor suppressor gene activates genes that cause a cell to stop growing, or even to kill itself (apoptosis). However, this activity should only be present if the cell is damaged. Therefore, the p53 protein is extensively regulated. In fact, p53 contains more than 18 phosphorylation sites. Phosphorylation is a very fast way of regulating proteins. In the simplest way of regulation, the protein is simply not there until it is needed. Steroid hormones like estrogen, for example, act as transcription factors, causing the proteins they regulate to be produced. However, this takes time, and it also takes time until the proteins degrade.
Necrosis - of necrosis including injury, infection, cancer, infarction, inflammation and so on. See also: Apoptosis Ebola haemorrhagic fever Gangrene.
Nobel Prize in Physiology or Medicine - D. Snell for discovery of the Major histocompatibility complex genes which encode cell surface molecules important for the immune system's distinction between self and non-self 1981 Roger W. Sperry, David H. Hubel, Torsten N. Wiesel Sperry for research on the cerebral hemispheres; Hubel and Wiesel for work on the processing of visual information in the brain 1982 Sune K. Bergström, Bengt I. Samuelsson, John R. Vane for the discovery of prostaglandins 1983 Barbara McClintock for discovery of mobile genetic elements or transposons in maize 1984 Niels K. Jerne, Georges J.F. Köhler, César Milstein for work on the immune system and the production of monoclonal antibodies 1985 Michael S. Brown, Joseph L. Goldstein for describing the regulation of cholesterol metabolism 1986 Stanley Cohen, Rita Levi-Montalcini for discovering growth factors 1987 Susumu Tonegawa.
Major histocompatibility complex - vast majority of the time, Mhc are kept busy presenting self-peptides, which the T cells should appropriately ignore. A full-force immune response usually requires the activation of B cells via BCRs and T cells via the Mhc-TCR interaction. This duplicity creates a system of "checks and balances" and underscores the immune system's potential for running amuck and causing harm to the body (see autoimmune disorders.) All Mhc molecules receive polypeptides from inside the cells they are part of and display them on the cell's exterior surface for recognition by T cells. However, there are major differences between MHC class I and II in the method and outcome of peptide presentation. Mhc Class I molecules are found on almost every nucleated cell of the body. Class I molecules are heterodimers, consisting of.
