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Mitochondrial Origin (mitochondrial + origin)
Selected AbstractsAbundant nuclear copies of mitochondrial origin (NUMTs) in the Aedes aegypti genomeINSECT MOLECULAR BIOLOGY, Issue 6 2009W. C. Black IV Abstract A portion of the Aedes aegypti mitochondrial NADH dehydrogenase subunit 4 gene (ND4) was amplified using PCR with a 42 °C annealing temperature. Amplified fragments from individual mosquitoes were similar to ND4 but contained multiple segregating sites. We suspected that nuclear copies of mitochondrial origin (NUMTs) exist in the Ae. aegypti genome. A BlastN search in VectorBase with the entire Ae. aegypti mitochondrial genome identified 233 NUMTs comprising 110 178 bp in 145 supercontigs. At a density of 0.080 bp/kb, this represents the second highest density of NUMTs in an insect genome and the highest in Diptera. Analyses of flanking sequences suggested that Ae. aegypti NUMTs arise through mtDNA leakage from damaged mitochondria followed by breakage and nonhomologous recombination, rather than through duplicative processes such as transposition or molecular drive. [source] Peripheral neuropathy associated with mitochondrial disorders: 8 cases and review of the literatureJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 4 2002S. Bouillot Abstract Forty-three cases of peripheral neuropathy (PN) have been reported in the literature with a proven mitochondria (mt) DNA mutation, and 21 had a peripheral nerve biopsy (PNB). We studied 8 patients, 1 of whom had severe sensory PN, 3 mild PN, and 4 subclinical PN. Nerve biopsy was performed in every case; all patients showed axonal degeneration and 4 showed features of primary myelin damage. In addition, there were 2 crystalline-like inclusions in the Schwann cell cytoplasm of a patient with MERRF, and 1 in a patient with multiple deletions on the mtDNA. There are 11 cases of PNB in the literature with axonal lesions, 5 with demyelination, and 4 with mixed lesions. One PNB was not modified. A few crystalline-like inclusions were seen in 1 case of MERRF. Such inclusions were first reported in the Schwann cell cytoplasm of unmyelinated fibers in a patient with Refsum disease and were considered to be modified mitochondria. However, their mitochondrial origin remains debatable. [source] The Bassian Isthmus and the major ocean currents of southeast Australia influence the phylogeography and population structure of a southern Australian intertidal barnacle Catomerus polymerus (Darwin)MOLECULAR ECOLOGY, Issue 8 2008KATHERINE L. YORK Abstract Southern Australia is currently divided into three marine biogeographical provinces based on faunal distributions and physical parameters. These regions indicate eastern and western distributions, with an overlap occurring in the Bass Strait in Victoria. However, studies indicate that the boundaries of these provinces vary depending on the species being examined, and in particular on the mode of development employed by that species, be they direct developers or planktonic larvae dispersers. Mitochondrial DNA sequence analysis of the surf barnacle Catomerus polymerus in southern Australia revealed an east,west phylogeographical split involving two highly divergent clades (cytochrome oxidase I 3.5 ± 0.76%, control region 6.7 ± 0.65%), with almost no geographical overlap. Spatial genetic structure was not detected within either clade, indicative of a relatively long-lived planktonic larval phase. Five microsatellite loci indicated that C. polymerus populations exhibit relatively high levels of genetic divergence, and fall into four subregions: eastern Australia, central Victoria, western Victoria and Tasmania, and South Australia. FST values between eastern Australia (from the eastern mitochondrial DNA clade) and the remaining three subregions ranged from 0.038 to 0.159, with other analyses indicating isolation by distance between the subregions of western mitochondrial origin. We suggest that the east,west division is indicative of allopatric divergence resulting from the emergence of the Bassian land-bridge during glacial maxima, preventing gene flow between these two lineages. Subsequently, contemporary ecological conditions, namely the East Australian, Leeuwin, and Zeehan currents and the geographical disjunctions at the Coorong and Ninety Mile Beach are most likely responsible for the four subregions indicated by the microsatellite data. [source] Proteome analysis of the thermoreceptive pit membrane of the western diamondback rattlesnake Crotalus atroxPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 1 2003Hans Zischka Abstract Rattlesnakes detect their prey's temperature by means of a cavern-like structure, the pit organ. The sensory component of this organ lies within a thin membrane called the pit membrane. Proteome analysis conducted on this neurosensory tissue revealed only a relatively small number of proteins, thereby depicting its high degree of specialization. In addition to containing blood serum and structural proteins, the proteome of this membrane appears to be strikingly similar to that of isolated rattlesnake brain mitochondria. Indeed, our results show that over 80% of the detected tissue proteins are of mitochondrial origin. Fluorescence microscopy studies of these organelles indicate their dense arrangement and accumulation in structures which have been previously reported to be the terminal ends of free nerve fibers of the innervating trigeminal branches. Thus, original ultrastructural observations are paralleled by our findings at the molecular level. [source] Chloride ATPase pumps in nature: do they exist?BIOLOGICAL REVIEWS, Issue 2 2003GEORGE A. GERENCSER ABSTRACT Five widely documented mechanisms for chloride transport across biological membranes are known: anioncoupled antiport, Na+ and H+ -coupled symport, Cl, channels and an electrochemical coupling process. These transport processes for chloride are either secondarily active or are driven by the electrochemical gradient for chloride. Until recently, the evidence in favour of a primary active transport mechanism for chloride has been inconclusive despite numerous reports of cellular Cl, -stimulated ATPases coexisting, in the same tissue, with uphill ATP-dependent chloride transport. Cl, -stimulated ATPase activity is a ubiquitous property of practically all cells with the major location being of mitochondrial origin. It also appears that plasma membranes are sites of Cl, -stimulated ATPase pump activity. Recent studies of Cl, -stimulated ATPase activity and ATP-dependent chloride transport in the same plasma membrane system, including liposomes, strongly suggest a mediation by the ATPase in the net movement of chloride up its electrochemical gradient across the plasma membrane structure. Contemporary evidence points to the existence of Cl, -ATPase pumps; however, these primary active transporters exist as either P-, F- or V-type ATPase pumps depending upon the tissue under study. [source] | ||||||||||