Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although several adaptive mechanisms have been identified that mask the existence of Parkinson's disease and delay the onset and aggravation of motor symptoms, the timescale and implications of this compensatory process remain an enigma. In order to examine: (i) the nature of the dopaminergic adaptive mechanisms that come into action; (ii) their sequential activation in relation to the severity of degeneration; and (iii) their efficacy with regard to the maintenance of a normal level of basal ganglia activity, we analysed the brains of mice treated daily with 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP, 4 mg/kg, i.p.) and killed at 5-day intervals from day 0 (D0) to D20. Our results demonstrate the sequential activation of two compensatory mechanisms: (i) an increase in striatal tyrosine hydroxylase (TH) protein content attested by the persistence of TH immunolabelling up to D15, contrasting with the decrease observed in both the number of nigral TH-immunoreactive neurons (-70.2%) and striatal dopamine content (-38.4%); (ii) a downregulation of DA uptake in surviving terminals at D20 (73.4% of nigral degeneration). At this point, the failure of adaptive mechanisms to maintain striatal dopaminergic homeostasis is also illustrated by an increase in the cytochrome oxidase activity of substantia nigra pars reticulata, a marker of neuronal function. It has been postulated that an increase in dopamine release per pulse could constitute an adaptive mechanism. The data we present from our MPTP mice model infirm this hypothesis. This study explores the link between the degree of nigral degeneration and the sequential activation of dopaminergic compensatory mechanisms in the nigrostriatal pathway and, in so doing, proposes a rethink of the paradigm applied to these mechanisms.
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PMID:Adaptive changes in the nigrostriatal pathway in response to increased 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurodegeneration in the mouse. 1097 32

The remarkably discontinuous distribution of the cave shrimp genus Troglocaris in South France, West Balkans, and West Caucasus has long been considered a biogeographic enigma. To solve it, its phylogeny was reconstructed by analyzing sequences from two mitochondrial (cytochrome oxidase I and 16S rRNA) and one nuclear gene (28S rRNA) using maximum likelihood, parsimony and Bayesian inference. The genus was found to be polyphyletic because the French taxon T. inermis had no direct common ancestry with other Troglocaris taxa but was sister to the epigean freshwater atyid Dugastella valentina. All other Troglocaris species constituted a well-supported monophylum, the second cave shrimp genus Spelaeocaris nested within. The monophylum had a well-defined structure: (1) a clade restricted to the Dinaric area of the Western Balkans containing the type species T. anophthalmus along with some unnamed species, and (2) a geographically mixed clade split between the Caucasian T. kutaissiana species complex on one, and T. hercegovinensis, S. pretneri, plus an unnamed taxon on the other side. It was surprising to find the dichotomy between the Caucasian and one of the West-Balkan lineages so low in the phylogenetic hierarchy of the genus. Taking into account molecular rates of other decapods, we tentatively dated this split at 6-11 Myr. This time is in agreement with the brackish and freshwater phase of the Paratethys thus allowing for a freshwater common ancestor of Caucasian and Dinaric cave shrimps. This would weaken the marine relicts hypothesis that has often been invoked to explain the distribution of freshwater cave species with close marine relatives.
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PMID:Phylogeny of the cave shrimp Troglocaris: Evidence of a young connection between Balkans and Caucasus. 1693 29