Biomaterial Database

Structure of animal mitochondrial DNA (base composition, pyrimidine clusters, character of methylation). 1977

B F Vanyushin, and M D Kirnos

Base composition, content of pyrimidine isopliths and methylation degree of mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) from various vertebrates and protozoon Crithidia oncopelti have been studied. mtDNAs from mammals (ox, rat) do not differ in fact in the G + C content from the respective nDNA. The G + C content in mtDNA from fishes (sheat-fish) and birds (duck, chicken) is 1.5--2.5 mol % higher than in the respective nDNA. Kinetoplast DNA (kDNA) from Crithidia oncopelti (G + C = 42.9 mol %) differs significantly in base composition from nDNA (G + C 51.3 mol%). All the mtDNA and kDNA studied differ from the respective nDNA by a lower degree of pyrimidine clustering. The amount of mono- and dipyrimidine fragments in mtDNA is more than 30 mol %, whereas in nDNA it does not exceed 23 mol %. The quantity of long pyrimidine clusters (hexa- and others) is 2--4 times lower in mtDNA than in nDNA. The lower degree of clustering of pyrimidine nucleotides seems to be a specific feature of all the mtDNA studied. This may be indicative of common traits in the organization and origin of mtDNA. All mtDNA of vertebrates contain 5-methylcytosine as "minor" base (1.5--3.15 mol %) and surpass by 1.5--2 times the respective nDNA in the methylation degree. It has been found that in animals mtDNA is species specific as far as the 5-methylcytosine content is concerned. mtDNA of beef heart differs significantly from nDNA in the mode of 5-methylcytosine distribution in pyrimidine isopliths, which may indicate that methylation specificity of nuclear and mitochondrial DNA is not the same. In mitochondria and nuclei of rat liver certain DNA-methylase activity has been detected, which provides in vitro the methylation of cytosine residues both in homologbous DNA and various heterologous DNAs. Specificity of methylation in vitro of cytosine residues in one and the same heterologous DNA from Escherichia coli B with nuclear and mitochondrial enzymes is different. Mitochondrial enzyme methylates cytosine residues chiefly in mono-, whereas nuclear enzyme, in di- and tripyrimidine fragments.

UI	MeSH Term	Description	Entries
D008745	Methylation	Addition of methyl groups. In histo-chemistry methylation is used to esterify carboxyl groups and remove sulfate groups by treating tissue sections with hot methanol in the presence of hydrochloric acid. (From Stedman, 25th ed)	Methylations
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D008930	Mitochondria, Liver	Mitochondria in hepatocytes. As in all mitochondria, there are an outer membrane and an inner membrane, together creating two separate mitochondrial compartments: the internal matrix space and a much narrower intermembrane space. In the liver mitochondrion, an estimated 67% of the total mitochondrial proteins is located in the matrix. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p343-4)	Liver Mitochondria,Liver Mitochondrion,Mitochondrion, Liver
D008931	Mitochondria, Muscle	Mitochondria of skeletal and smooth muscle. It does not include myocardial mitochondria for which MITOCHONDRIA, HEART is available.	Sarcosomes,Mitochondrion, Muscle,Muscle Mitochondria,Muscle Mitochondrion,Sarcosome
D009206	Myocardium	The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.	Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
D009928	Organ Specificity	Characteristic restricted to a particular organ of the body, such as a cell type, metabolic response or expression of a particular protein or antigen.	Tissue Specificity,Organ Specificities,Specificities, Organ,Specificities, Tissue,Specificity, Organ,Specificity, Tissue,Tissue Specificities
D011743	Pyrimidines	A family of 6-membered heterocyclic compounds occurring in nature in a wide variety of forms. They include several nucleic acid constituents (CYTOSINE; THYMINE; and URACIL) and form the basic structure of the barbiturates.
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D002467	Cell Nucleus	Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)	Cell Nuclei,Nuclei, Cell,Nucleus, Cell
D002645	Chickens	Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.	Gallus gallus,Gallus domesticus,Gallus gallus domesticus,Chicken