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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Mutator Phenotype - Myxoedema
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Mutations, somatic
Mutations that occur in somatic cells as opposed to germ cells. Somatic mutations are not passed on to the offspring unlike germline mutations.
Mutator loci
Genes whose functions are associated with the fidelity of DNA replication such as mut D, mut U and mut Y.
Mutator phenotype
A strong tendency to undergo mutation expressed by any organism that carries a mutation in a gene involved in maintaining the fidelity of DNA replication.
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Muteins
Modified therapeutic proteins with improved or novel biological activities produced by mutagenesis in vitro.
MutH
A protein required for recognition of mutation and nicking of the strand in E.coli during mismatch repair. MutH, which is linked to MutS by MutLm has site-specific endonuclease activity by which it cleaves the unmethylated DNA strand. This marks the strand for repair.
MutL
A protein required for recognition of mutation and nicking of the strand in E.coli during mismatch repair together with MutS and MutL.
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Muton
A unit of genetic mutation.
MutS
A protein required for recognition of mutation and nicking of the strand in E.coli during mismatch repair. MutS recognises the mismatch and binds to it.
Mutualism
See symbiosis.
MMC model
See Monod, Wyman and Changeaux model.
Myalgia
Muscle pain.
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Myasthenia gravis
An autoimmune disease of the nervous system caused by one’s own neurotransmitter receptors. The disease is characterised by progressive paralysis of the motor neuron.
Myb oncogene
myb is acronym for myeloblastoma. An oncogene carried by the avian myeloblastosis virus that cause myeloblastic leukaemia in chickens.
Myc oncogene
myc is an acronym for myelocytomatosis. An oncogene carried by the avian leucosis retrovirus that causes leukaemia in birds.
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Mycelium (pl: mycelia)
1. The sheet-like growth of some bacteria. 2. A mass of interwoven thread-like filaments of a fungus.
Mycobacteria
A group of rod-shaped acidophilic bacteria that cause diseases such as leprosy and tuberculosis.
Mycology
The study of fungi.
Mycoplasma
The smallest independently growing organisms known. These were isolated based on their ability to cause pneumonia. These are also known as pleuropneumonia-like organisms (PPLO).
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Mycorprotein
Fungal protein.
Mycorrihiza
Fungi that develop an association with or have a symbiotic relationship with roots of more developed plants.
Mycotoxin
Toxic substance of fungal origin, such as aflatoxin.
Myelin sheath
A specialised cell membrane wrapped around axons which functions as an insulator. It is formed by oligodendrocytes in the central nervous system and by Schwann cells in the peripheral nervous system.
Myeloid cell
A white blood cell other than the lymphocyte.
Myeloma
A tumour comprised of plasma cells found in the bone marrow.
Myeloma proteins
An antibody molecule secreted by a myeloma tumour.
Myoblast
An undifferentiated, mononucleated precursor cell of a muscle.
Myocardial infarction (MI)
Necrosis of heart muscle tissue due to an interruption in the blood supple to the heart. This may be due to obstruction of a coronary artery by a clot a result of atherosclerosis. Commonly known as a heart attack.
Myocytes
Muscle cells.
MyoD
A family of myogenic protein that induces cells to differentiate into muscle cells. It exhibits the helix-loop-helix motif characteristic of certain transcription factors and induces the transcription of myogenin.
Myoepithelial cell
An unstriated muscle cell present in the epithelia (eg. glandular tissue).
Myofibril
A unit of the thick and thin filaments in a muscle fibre.
Myoglobin
The oxygen transport protein present in muscle tissue. Unlike haemoglobin, myoglobin is a monomer.
Myoglobinuria
Presence of myoglobin in urine. Myoglobin is found in urine in conditions where there is breakdown of muscle as in crush injuries, burns, electric shock, malignant hyperthermia etc. Myoglobin is released from myocardium following infarction and in paroxysmal myoglobinuria after exercise.
Myoinositol
See inositol.
Myosin
The predominant protein in the thick filaments of a myofibril. It contains two coiled subunits each of molecular weight 220 000 that aggregate to form a thick filament.
Myositis
Inflammation of a voluntary muscle.
Myxobacteria
Bacteria that live in the soil as individual cells under limiting conditions and form Multicellular aggregates.
Myxoedema
A characteristic clinical manifestation of hypothyroidism in adults. There is an oedematous appearance throughout the body with periorbital puffiness and dry, waxy, nonpitting type of swelling with abnormal deposition of mucin in the skin and other tissues. There is thickening of the skin due to infiltration of proteoglycans. The hair and skin become dry and the voice becomes hoarse. Stiffness and cramps, carpal tunnel syndrome and slowing of intellectural and motor activity occur. In severe untreated cases, myxoedema coma, a hypothermic, fatal stupor develops.
Myxoedema coma
A hypothermic, fatal stupor that develops in severe untreated cases of hypothyroidism. Factors that predispose to myxoedema coma include trauma, infection, exposure to cold and narcotics.
Myxovirus
Viruses that cause influenza. These are divided into two families-orthomyxoviruses and paramyxoviruses.
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