Roger Débise

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The consequences of aging are characterized by a decline in the main cellular functions, including those of the mitochondria. Although these consequences have been much studied, efforts have often focused solely on a few parameters used to assess the "state" of mitochondrial function during aging. We performed comparative measurements of several parameters(More)
Eighty percent of DNA molecules are deleted in the mitochondrial population of an adult mutant strain of D. subobscura. Both intact and deleted genomes are autonomous monomers. The heteroplasmy level, which is lower in germ tissue, increases from the oocytes (60%) to the third larval instar (83%), and is then maintained throughout the life of the fly. The(More)
Analysis of a mutant strain of Drosophila subobscura revealed that most (80%) mitochondrial genomes have undergone a large scale deletion (5 kb) in the coding region. Compared with the wild-type strain, complex I and III activities are, respectively, reduced by 50% and 30% in the mutant. However, the ATP synthesis capacities remain unchanged. In order to(More)
In the studied mutant strain of Drosophila subobscura, 78% of the mitochondrial genomes lost >30% of the coding region by deletion. The mutations was genetically stable. Despite this massive loss of mitochondrial genes, the mutant did not seem to be affected. Distribution of the two genome types, cell levels of mitochondrial DNA, steady-state concentrations(More)
Our data clearly demonstrate that protective effect of phosphate and protective effect of mersalyl against NEM-inhibition of phosphate transport act at the level of two kinds of proteins. (1)Two major components are phosphate and nigericin NEM sensitive. According to our previous data [13] it has been also demonstrated that these two proteins components are(More)
A mutant strain of D. Subobscura possesses two populations of mitochondrial genomes: a population identical to that of the wild strain (20%) and a dominant population (80%) which has lost more than 30% of its coding zone by deletion. Spectrophotometric determination of respiratory complex activities shows that: complex I (5 genes implicated in deletion)(More)
We have characterized the ribosomal proteins from Spinacia chloroplasts using two-dimensional gel electrophoresis. The 30S and 50S subunits contain 23–25 and 36 ribosomal proteins, respectively. In contrast to prokaryotic ribosomes, chloroplast ribosomes contain at least one (and possibly two) phosphorylated ribosomal proteins. Isolated chloroplasts(More)
The alkali cations discrimination on a liquid membrane electrodes system, was determined for the carboxylic ionophores grisorixin, alborixin and two derivatives, dihydrogrisorixin and hexahydroalborixin. The two antibiotics exhibited a great perference for K+. Dihydrogrisorixin again showed the selectivity curve of a carboxylic ionophore, but with a(More)