A mitochondrial mutator plasmid that causes senescence under dietary restricted conditions

Background

The definition of human MHC class I haplotypes through association of HLA-A, HLA-Cw and HLA-B has been used to analyze ethnicity, population migrations and disease association.

Results

Here, we present HLA-E allele haplotype association and population linkage disequilibrium (LD) analysis within the ~1.3 Mb bounded by HLA-B/Cw and HLA-A to increase the resolution of identified class I haplotypes. Through local breakdown of LD, we inferred ancestral recombination points both upstream and downstream of HLA-E contributing to alternative block structures within previously identified haplotypes. Through single nucleotide polymorphism (SNP) analysis of the MHC region, we also confirmed the essential genetic fixity, previously inferred by MHC allele analysis, of three conserved extended haplotypes (CEHs), and we demonstrated that commercially-available SNP analysis can be used in the MHC to help define CEHs and CEH fragments.

Conclusion

We conclude that to generate high-resolution maps for relating MHC haplotypes to disease susceptibility, both SNP and MHC allele analysis must be conducted as complementary techniques.     

Maged1, a new regulator of skeletal myogenic differentiation and muscle regeneration

Background  

In normal adult skeletal muscle, cell turnover is very slow. However, after an acute lesion or in chronic pathological conditions, such as primary myopathies, muscle stem cells, called satellite cells, are induced to proliferate, then withdraw definitively from the cell cycle and fuse to reconstitute functional myofibers.     

Effect of cocarboxylase on hyperlactatemia and hyperpyruvicemia induced by phenformin in dogs]

In the normal anesthetized dog, a cocarboxylase perfusion considerably reduced the increase in blood lactate and pyruvate levels provoked by the intraduodenal injection of phenformin (30 mg/kg); furthermore it seems to counteract the increase of the lactates/pyruvates ratio and opposes the fall in blood pH.     

Effects of pancreastatin on pancreatic hormone secretion in the dog

In the anaesthetized dog, porcine pancreastatin (98 pmol/min) was infused for 10 min into the pancreaticoduodenal artery either alone or during infusion of glucose. Blood was sampled from the pancreaticoduodenal vein. We found that pancreastatin inhibited pancreatic insulin output only under normoglycaemic conditions. Furthermore, pancreastatin significantly stimulated pancreatic glucagon and somatostatin outputs both during normo- and hyperglycaemic conditions. Our results show that pancreastatin has the capability to affect directly the three pancreatic hormone secretions in dogs.     

Evolution of SINE S1 retroposons in Cruciferae plant species

The S1 element is a plant short interspersed element (SINE) that was first described and studied in Brassica napus. In this work, we investigated the distribution and the molecular phylogeny of the S1 element within the Cruciferae (= Brassicaceae). S1 elements were found to be widely distributed within the Cruciferae, especially in species of the tribe Brassiceae. The molecular phylogeny of S1 elements in eight Cruciferae species (Brassica oleracea, Brassica rapa, Brassica napus, Brassica nigra, Sinapis, arvensis, Sinapis pubescens, Coincya monensis, and Vella spinosa) was inferred using 14-36 elements per species. Significant neighbor-joining and maximum-parsimony phylogenetic clusters, supported by high bootstrap P values and/or represented in 100% of the most-parsimonious trees, were observed for each species. Most of these clusters probably correspond to recent species-specific bursts of S1 amplification. Since these species diverged recently, S1 amplification in Cruciferae plants is proposed to be a highly dynamic process that could contribute to genome rearrangements and eventually lead to reproductive isolation. S1 sequence analysis also revealed putative gene conversion events that occurred between different S1 elements of a given species. These events suggest that gene conversion is a minor but significant component of the molecular drive governing S1 concerted evolution.