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M Paturneau-Jouas

Publications and source records attributed to M Paturneau-Jouas.

8 recordsLinked to original sources
PubMed1991

Deletions of mitochondrial DNA in Kearns-Sayre syndrome and ocular myopathies: genetic, biochemical and morphological studies.

Genetic, biochemical and morphological investigations were conducted on skeletal muscle mitochondria from 6 cases of ocular myopathy: 4 cases with Kearns-Sayre syndrome (KSS) and 2 with chronic progressive external ophthalmoplegia. All of these 6 cases showed mitochondrial DNA (mtDNA) deletions in addition to normal sized DNA in the quadriceps muscle. The deletions ranging from 3 to 8 kbp were also mapped between nucleotides 5500 and 16000 by Southern blot. The deleted genes encoded for some subunits of complexes I, IV, V and 5-10 tRNAS. The boundaries of the deletions have been sequenced in three patients. Five patients had mitochondrial respiratory chain deficiency in complex I as shown by the low oxygen consumption in isolated mitochondria using three NAD(+)-linked substrates. Mitochondria with an abnormal ultrastructure were also observed in 2 cases. A good relationship between the cytochrome c oxidase deficiency and the amount of deleted mtDNA was shown in our present investigations.

Adult↗
PubMed1991

Genetic biochemical and pathophysiological characterization of a familial mitochondrial encephalomyopathy (MERRF).

Myoclonic epilepsy with ragged-red fibers (MERRF) syndrome is a neuromuscular disorder characterized by mitochondrial myopathy and progressive myoclonus epilepsy. A heteroplasmic A to G transition mutation in the mitochondrial encoded tRNA(Lys) gene at nucleotide pair 8344 has been suggested to be linked to the MERRF-syndrome. We have investigated biochemically and histochemically muscle biopsies and studied the mitochondrial genomes of hair, blood and muscle tissue of a family including three cases of MERRF-syndrome as well as unaffected relatives within the maternal lineage. Sequence analysis of the mtDNAs, performed after amplification by the polymerase chain reaction (PCR), confirmed the A to G transition mutation in the tRNA(Lys) gene at position 8344. The additional point mutation at nucleotide pair 750 in the 12 S rRNA gene, which was also found by Shoffner et al. (1990), however, was absent in all investigated tissues. Quantitative analysis of the percentage of mutated mtDNA by mispairing PCR (Seibel et al., 1990) revealed variable contents in different tissues and individuals, including unaffected family members. Mitochondrial protein synthesis in cultured fibroblasts from MERRF patients revealed diminished incorporation of 35S-methionine into lysine-containing peptides.

Adolescent↗
PubMed1976

[Biosynthesis of lignoceric acid in two organelles (mitochondria and microsomes) during the development of the brain in normal and pathologic (Quaking and Jimpy) mice].

In microsomes, biosynthesis of lignoceric acid from its direct precursor (behenyl-CoA) is largely increased during myelination. The peak is hardly detectable in Quaking; in Jimpy, the synthesis is nearly absent (3% of normal value); in the adult Quaking, the synthesis is normal. Mitochondria are capable of synthesizing lignoceric acid. This synthesis increases regularly during brain development and is normal in both mutants. Saturated fatty acid analysis is brain mitochondria shows that these organelles contain mainly palmitic and stearic acids. However, very long chains are also detectable. Thus it appears that mitochondria synthesize their own acids. Microsomes synthesize their own acids also and myelin fatty acids. There is no interplay between microsomal and mitochondrial metabolisms.

Age Factors↗
PubMed1976

[Biosynthesis of fatty acids in mouse brain mitochondria in the presence of malonyl-CoA or acetyl-CoA].

Incorporation of malonyl-CoA or acetyl-CoA is studied in mouse brain mitochondrial fatty acids. Rupture of mitochondria is necessary ; Triton X-100 gives the best result. Other detergents or sonication are of lesser efficiency. Cofactor requirements have been studied : NADH and NADPH have been tested ; ATP increases biosynthesis and CoA causes an inhibition. Two systems of biosynthesis are involved : -- One is a de novo system using malonyl-CoA. Malonyl-CoA alone is incorporated and synthesizes mainly C16, indicating the existence of a malonly-CoA decarboxylase although elongation of short chain fatty acids cannot be excluded. Addition of acetyl-CoA increases the biosynthesis and palmityl-CoA when added causes an inhibition. -- The other system, using acetyl-CoA, elongates exogenous palmityl-CoA ; endogenous acyl-CoAs are not elongated by acetyl-CoA. All these results are confirmed by radiogas chromatographic studies of the reactions products.

Acetyl Coenzyme A↗