Mitochondrion structure

Moore AL, Beechey RB. Plant Mitochondria Structural, Functional and Physiological Aspects, Plenum Press, New York, 1987. 

One of the main questions is whether this sudden collapse is closely associated with the loss of mitochondria structure and function, loss of energy production, protein synthesis, and the status of cytoplasmic and/or mitochondrial GSH. 

Electron Transfer Chain, Chemistry of Metabolic Diseases, Chemical Biology of Mitochondria, Structural Dynamics of Mitochondrial Proteomics Oxidative Metabolism, Chemistry of... 

The general field with which this review is concerned is currently one of the most exciting in chemical physics, the study of kinetic processes in systems of finite size and/or of restricted dimensionality. Problems ranging from the study of organized molecular assemblies (micelles, vesicles, microemulsions), biological systems (cells, microtubules, chloroplasts, mitochondria), structured media such as clays and zeolites, and nucleation phenomena in finite domains are among those under active investigation. 

Disarrangement of mitochondria structure, fusion of mitochondria, and formation of residual bodies were observed in the liver and pancreas of dogs (9 to 16 kg each) orally administered 2 g of a dried chloroform extract of... 

Sbis. Ernster, L., Mitochondria. Structure and Function. Academic Press, New York, 1969. 

Volume 4 Mitochondria Structure, Biogenesis and Transducing Functions... 

Assuming a protein unit of molecular weight 64,000 such as the monomeric unit of mitochondria structural proteins, (Lenaz et al., 1968) the value of R is — 58 A (area = 8900 A ). ... 

Experimental data offered as evidence for hydrophobic bonding of lipids to protein by Green and Tzagaloff (1966) can be readily given interpretations which exclude hydrophobic bond involvement of the protein with lipid chains. For example, (1) the stronger binding to mitochondrion structural protein of lipids with longer acyl chains... 

Not all the cellular DNA is in the nucleus some is found in the mitochondria. In addition, mitochondria contain RNA as well as several enzymes used for protein synthesis. Interestingly, mitochond-rial RNA and DNA bear a closer resemblance to the nucleic acid of bacterial cells than they do to animal cells. For example, the rather small DNA molecule of the mitochondrion is circular and does not form nucleosomes. Its information is contained in approximately 16,500 nucleotides that func-tion in the synthesis of two ribosomal and 22 transfer RNAs (tRNAs). In addition, mitochondrial DNA codes for the synthesis of 13 proteins, all components of the respiratory chain and the oxidative phosphorylation system. Still, mitochondrial DNA does not contain sufficient information for the synthesis of all mitochondrial proteins most are coded by nuclear genes. Most mitochondrial proteins are synthesized in the cytosol from nuclear-derived messenger RNAs (mRNAs) and then transported into the mito-chondria, where they contribute to both the structural and the functional elements of this organelle. Because mitochondria are inherited cytoplasmically, an individual does not necessarily receive mitochondrial nucleic acid equally from each parent. In fact, mito-chondria are inherited maternally. 

Subsurface cisternae are a system of smooth, membrane-bound, flattened cisternae that can be found in many neurons. These structures, referred to as hypolemmal cisternae by Palay and Chan-Palay [1], abut the plasmalemma of the neuron and constitute a secondary membranous boundary within the cell. The distance between these cisternae and the plasmalemma is usually 10-12 nm and, in some neurons, such as the Purkinje cells, a mitochondrion may be found in close association with the innermost leaflet. Similar cisternae have been described beneath synaptic complexes, but their functional significance is not... 

In spite of the variety of appearances of eukaryotic cells, their intracellular structures are essentially the same. Because of their extensive internal membrane structure, however, the problem of precise protein sorting for eukaryotic cells becomes much more difficult than that for bacteria. Figure 4 schematically illustrates this situation. There are various membrane-bound compartments within the cell. Such compartments are called organelles. Besides the plasma membrane, a typical animal cell has the nucleus, the mitochondrion (which has two membranes see Fig. 6), the peroxisome, the ER, the Golgi apparatus, the lysosome, and the endosome, among others. As for the Golgi apparatus, there are more precise distinctions between the cis, medial, and trans cisternae, and the TGN trans Golgi network) (see Fig. 8). In typical plant cells, the chloroplast (which has three membranes see Fig. 7) and the cell wall are added, and the lysosome is replaced with the vacuole. 

Fig. 3. Secondary structure comparison between the RNA molecules from the small ribosomal subunits of human mitochondrion, E. coli, and yeast (Brimacombe, 1983). Relations between a, b, and c are as in Fig. 2.

The theory has been advanced that there exists in the cell a particulate structure somewhat smaller than the mitochondrion, the lyso-some, that contains certain autolytic enzymes in a latent situation. The lysosome theory55,56 is very largely based upon measurements made in sucrose homogenates of rodent liver. Although the results for a-D-mannosidase in this tissue (see Table IV) are not incompatible with the theory, the results for other tissues do not always conform to it. In particular, the contrast between mouse and rat spleen argues against a universal single particle to which a-D-mannosidase is confined. Apart from the results quoted in Table IV, not much work has been done on the intracellular location of a-D-mannosidase. 

Benchimol M, De Souza W (1983) Fine structure and cytochemistry of the hydrogeno-some of Tritrichomonas foetus. J Protozool 30 422-425 Boxma B, de Graaf RM, van der Staay GWM, van Alen , Ricard G, Gabaldon T, van Hoek AHAM, Moon-van der Staay S, Koopman WJH, van Hellemond JJ, Tielens AGM, Friedrich T, Veenhuis M, Huynen MA, Hackstein JHP (2005) An anaerobic mitochondrion that produces hydrogen. Nature 434 74-79... 

Because Rlil homologs have been found only in archaebacteria (reviewed in Tachezy and Dolezal 2007), it is hypothesized that Rlil and other components of cytosolic translation machinery are derived from them. Therefore, we propose that the intimate association of the relic mitochondrion, of eubacterial origin, with its associated membranes is a structural reflection of the cell s attempt to facilitate efficient ribosome biogenesis and translation initiation following reductive evolution of the organelle (Keeling 2004 ... 

One of the most puzzling structures within C. parvum sporozoites, is the crystalloid body (CB), which is also in intimate contact with the relic mitochondrion, outer nuclear membrane, and RER (Fig. 1) (Keithly et al. 2005). Although it is still unclear whether this organelle is surrounded by a limiting membrane, or is simply a complex of closely packed membrane-bounded vesicles, it has been shown that like the relic mitochondrion, the CB takes up mitotracker dyes (Ctrnacta et al. 2006 Kayser et al. 2002 Keithly et al. 

Haresh K, Suresh K, Khairul Anus A, Saminathan S (1999) Isolate resistance of Blastocystis hominis to metronidazole. Trop Med Int Health 4 274-277 Inui H, Ono K, Miyatake K, Nakano Y, Kitaoka S (1987) Purification and characterization of pyruvate NADP+ oxidoreductase in Euglena gracilis. J Biol Chem 262 9130-9135 Keithly JS, Langreth SG, Buttle KF, Mannella CA (2005) Electron tomographic and ultra-structural analysis of the Cryptosporidium parvum relict mitochondrion, its associated membranes, and organelles. J Eukaryot Microbiol 52 132-140 Kurland CG, Andersson SGE (2000) Origin and evolution of the mitochondrial proteome. Micro Mol Biol Rev 64 786-820... 

Vitamin B12 consists of a porphyrin-like ring structure, with an atom of Co chelated at its centre, linked to a nucleotide base, ribose and phosphoric acid (6.34). A number of different groups can be attached to the free ligand site on the cobalt. Cyanocobalamin has -CN at this position and is the commercial and therapeutic form of the vitamin, although the principal dietary forms of B12 are 5 -deoxyadenosylcobalamin (with 5 -deoxyadeno-sine at the R position), methylcobalamin (-CH3) and hydroxocobalamin (-OH). Vitamin B12 acts as a co-factor for methionine synthetase and methylmalonyl CoA mutase. The former enzyme catalyses the transfer of the methyl group of 5-methyl-H4 folate to cobalamin and thence to homocysteine, forming methionine. Methylmalonyl CoA mutase catalyses the conversion of methylmalonyl CoA to succinyl CoA in the mitochondrion. 

The mechanism by which the mineral leaves the mitochondrion is only one of the problems of this theory. The mineral in the mitochondrion exists in association with the fluid contents. Thus, unless this water is in some structural form with abnormal solubilities, the mineral must be saturating the fluid, and solubility products apply. It follows that the mitochondrial calcium and phosphate concentrations must be similar to those of the extracellular fluids, i. e. calcium must be concentrated thousandfold to overcome the low intracellular values. 

Structure of the mitochondrion The components of the electron transport chain are located in the inner membrane. Although the outer membrane contains special pores, making it freely perme-... 

Structure of a mitochondrion showing schematic representation of the electron transport chain and ATP synthesizing structures on the inner membrane. mtDNA = mitochondrial DNA mtRNA = mitochondrial RNA. 

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