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AMPD3
AMP deaminase 3 is an enzyme that in humans is encoded by the ''AMPD3'' gene. This gene encodes a member of the AMP deaminase gene family. The encoded protein is a highly regulated enzyme that catalyzes the hydrolytic deamination of adenosine monophosphate to inosine monophosphate, a branch point in the adenylate catabolic pathway. This gene encodes the erythrocyte (E) isoforms, whereas other family members encode isoforms that predominate in muscle (M) and liver (L) cells. Mutations in this gene lead to the clinically asymptomatic, autosomal recessive condition erythrocyte AMP deaminase deficiency. Alternatively spliced transcript variants encoding different isoforms of this gene have been described. Model organisms Model organisms have been used in the study of AMPD3 function. A conditional knockout mouse line, called ''Ampd3tm2a(KOMP)Wtsi'' was generated as part of the International Knockout Mouse Consortium program — a high-throughput mutagenesis project to generate and d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AMP Deaminase
AMP deaminase 1 is an enzyme that in humans is encoded by the ''AMPD1'' gene. Adenosine monophosphate deaminase is an enzyme that converts adenosine monophosphate (AMP) to inosine monophosphate (IMP), freeing an ammonia molecule in the process. Function Adenosine monophosphate deaminase 1 catalyzes the deamination of AMP to IMP in skeletal muscle and plays an important role in the purine nucleotide cycle. Two other genes have been identified, AMPD2 and AMPD3, for the liver- and erythrocyte-specific isoforms, respectively. Deficiency of the muscle-specific enzyme is apparently a common cause of exercise-induced myopathy and probably the most common cause of metabolic myopathy in the human. A research report shows that the widely prescribed diabetes medication metformin works on AMP-activated kinase (AMPK) by directly inhibiting AMP deaminase, thereby increasing cellular AMP. Regulation It has been shown that in environments with high potassium concentrations, AMP-deaminase i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micronucleus Test
A micronucleus test is a test used in toxicological screening for potential genotoxic compounds. The assay is now recognized as one of the most successful and reliable assays for genotoxic carcinogens, i.e., carcinogens that act by causing genetic damage and is recommended by the OECD guideline for the testing of chemicals. There are two major versions of this test, one ''in vivo'' and the other ''in vitro''. The ''in vivo'' test normally uses mouse bone marrow or mouse peripheral blood. When a bone marrow erythroblast develops into a polychromatic erythrocyte, the main nucleus is extruded; any micronucleus that has been formed may remain behind in the otherwise anucleated cytoplasm. Visualisation of micronuclei is facilitated in these cells because they lack a main nucleus. An increase in the frequency of micronucleated polychromatic erythrocytes in treated animals is an indication of induced chromosome damage. Micronuclei were first used to quantify chromosomal damage by H.J. Ev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Splenomegaly
Splenomegaly is an enlargement of the spleen. The spleen usually lies in the left upper quadrant (LUQ) of the human abdomen. Splenomegaly is one of the four cardinal signs of ''hypersplenism'' which include: some reduction in number of circulating blood cells affecting granulocytes, erythrocytes or platelets in any combination; a compensatory proliferative response in the bone marrow; and the potential for correction of these abnormalities by splenectomy. Splenomegaly is usually associated with increased workload (such as in hemolytic anemias), which suggests that it is a response to hyperfunction. It is therefore not surprising that splenomegaly is associated with any disease process that involves abnormal red blood cells being destroyed in the spleen. Other common causes include congestion due to portal hypertension and infiltration by leukemias and lymphomas. Thus, the finding of an enlarged spleen, along with caput medusae, is an important sign of portal hypertension. Definiti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erythropoiesis
Erythropoiesis (from Greek 'erythro' meaning "red" and 'poiesis' "to make") is the process which produces red blood cells (erythrocytes), which is the development from erythropoietic stem cell to mature red blood cell. It is stimulated by decreased O2 in circulation, which is detected by the kidneys, which then secrete the hormone erythropoietin.Sherwood, L, Klansman, H, Yancey, P: ''Animal Physiology'', Brooks/Cole, Cengage Learning, 2005. This hormone stimulates proliferation and differentiation of red cell precursors, which activates increased erythropoiesis in the hemopoietic tissues, ultimately producing red blood cells (erythrocytes). In postnatal birds and mammals (including humans), this usually occurs within the red bone marrow. In the early fetus, erythropoiesis takes place in the mesodermal cells of the yolk sac. By the third or fourth month, erythropoiesis moves to the liver. After seven months, erythropoiesis occurs in the bone marrow. Increased levels of physical ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Blood Cell
Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "hollow vessel", with ''-cyte'' translated as "cell" in modern usage), are the most common type of blood cell and the vertebrate's principal means of delivering oxygen (O2) to the body tissues—via blood flow through the circulatory system. RBCs take up oxygen in the lungs, or in fish the gills, and release it into tissues while squeezing through the body's capillaries. The cytoplasm of a red blood cell is rich in hemoglobin, an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells and the blood. Each human red blood cell contains approximately 270 million hemoglobin molecules. The cell membrane is composed of proteins and lipids, and this structure provides properties essential for physiolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3rd Ventricle
The third ventricle is one of the four connected ventricles of the ventricular system within the mammalian brain. It is a slit-like cavity formed in the diencephalon between the two thalami, in the midline between the right and left lateral ventricles, and is filled with cerebrospinal fluid (CSF). Running through the third ventricle is the interthalamic adhesion, which contains thalamic neurons and fibers that may connect the two thalami. Structure The third ventricle is a narrow, laterally flattened, vaguely rectangular region, filled with cerebrospinal fluid, and lined by ependyma. It is connected at the superior anterior corner to the lateral ventricles, by the interventricular foramina, and becomes the cerebral aqueduct (''aqueduct of Sylvius'') at the posterior caudal corner. Since the interventricular foramina are on the lateral edge, the corner of the third ventricle itself forms a bulb, known as the ''anterior recess'' (it is also known as the ''bulb of the ventricle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratum Radiatum
In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as either '' bedding surfaces'' or ''bedding planes''.Salvador, A. ed., 1994. ''International stratigraphic guide: a guide to stratigraphic classification, terminology, and procedure. 2nd ed.'' Boulder, Colorado, The Geological Society of America, Inc., 215 pp. . Prior to the publication of the International Stratigraphic Guide, older publications have defined a stratum as either being either equivalent to a single bed or composed of a number of beds; as a layer greater than 1 cm in thickness and constituting a part of a bed; or a general term that includes both ''bed'' and ''lamina''.Neuendorf, K.K.E., Mehl, Jr., J.P., and Jackson, J.A. , eds., 2005. ''Glossary of Geology'' 5th ed. Alexandria, Virginia, American Geological Institute. 779 pp. . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trabecular Bone
A trabecula (plural trabeculae, from Latin for "small beam") is a small, often microscopic, tissue element in the form of a small beam, strut or rod that supports or anchors a framework of parts within a body or organ. A trabecula generally has a mechanical function, and is usually composed of dense collagenous tissue (such as the trabecula of the spleen). It can be composed of other material such as muscle and bone. In the heart, muscles form trabeculae carneae and septomarginal trabeculae. Cancellous bone is formed from groupings of trabeculated bone tissue. In cross section, trabeculae of a cancellous bone can look like septa, but in three dimensions they are topologically distinct, with trabeculae being roughly rod or pillar-shaped and septa being sheet-like. When crossing fluid-filled spaces, trabeculae may offer the function of resisting tension (as in the penis, see for example trabeculae of corpora cavernosa and trabeculae of corpus spongiosum) or providing a cell fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutant
In biology, and especially in genetics, a mutant is an organism or a new genetic character arising or resulting from an instance of mutation, which is generally an alteration of the DNA sequence of the genome or chromosome of an organism. It is a characteristic that would not be observed naturally in a specimen. The term mutant is also applied to a virus with an alteration in its nucleotide sequence whose genome is in the nuclear genome. The natural occurrence of genetic mutations is integral to the process of evolution. The study of mutants is an integral part of biology; by understanding the effect that a mutation in a gene has, it is possible to establish the normal function of that gene. Mutants arise by mutation Mutants arise by mutations occurring in pre-existing genomes as a result of errors of DNA replication or errors of DNA repair. Errors of replication often involve translesion synthesis by a DNA polymerase when it encounters and bypasses a damaged base in the temp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenotypic Screen
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological properties, its behavior, and the products of behavior. An organism's phenotype results from two basic factors: the expression of an organism's genetic code, or its genotype, and the influence of environmental factors. Both factors may interact, further affecting phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic. A well-documented example of polymorphism is Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 and then again in his 1982 book ''The Extended Phenotype'' suggested that one can regard bird nests and other built structures such as caddi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Knockout Mouse Consortium
The International Knockout Mouse Consortium (IKMC) is a scientific endeavour to produce a collection of mouse embryonic stem cell lines that together lack every gene in the genome, and then to distribute the cells to scientific researchers to create knockout mice to study. Many of the targeted alleles are designed so that they can generate both complete and conditional gene knockout mice. The IKMC was initiated on March 15, 2007 at a meeting in Brussels. By 2011, ''Nature'' reported that approximately 17,000 different genes have already been disabled by the consortium, "leaving only around 3,000 more to go". The consortium encompasses four major, high-throughput gene-targeted mutagenesis programs: the National Institutes of Health (NIH)-sponsored Knockout Mouse Program (KOMP) and state-funded Texas Institute for Genomic Medicine (TIGM) in the U.S., the North American Conditional Mouse Mutagenesis (NorCOMM) Program in Canada, and the European Conditional Mouse Mutagenesis (EUCOMM) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
