Polyclony and low relative heterozygosity in a widespread unisexual vertebrate,Lepidodactylus lugubris (Sauria)

Contrary to other unisexual vertebrates except a little-known fossorial snake, the Indo-Pacific anthropophilous, parthenogenetic lacertilian Lipododactylus lugubris is vastly more widespread than its bisexual relatives. At the same time, it shows negligible enzyme polymorphism and low overall heterozygosity in its usual diploid condition, which suggests the possibility that hybridization did not intervene when thelytoky was brought about. Clones are in much higher proportion among the sympatric triploids, but they too have a low relative heterozygosity, compounded by gene dosage restriction since no more than two out of the three alleles have been found expressed at any locus. Isozyme data suggest an origin of the complex in South East Asia, which conclusion is substantiated by the presence of a bisexual sibling species in the Philippine Islands.     

QTLs for fertility in table grape (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.)

Fertility (number of inflorescences per shoot) is a trait of major importance for grapevine breeding. We present and compare the results of quantitative trait locus (QTL) detection for fertility in two table grape progenies, MTP3140 and MTP3234. Novel parental and consensus maps were built for MTP3140. We found a main QTL on linkage group (LG) 5 in both progenies, which was also the most stable one across years. It explained up to 18.5% of the total intra-cross phenotypic variance. Three other QTLs, one on LG 5 and two on LG 14, were repeated over years but were found in a single progeny. Our results suggest that QTLs effect was mainly additive. The prospects for testing candidate genes are discussed as well as the potential interest of these results for marker-assisted selection.     

Chromosome integration of BAC (bacterial artificial chromosome): evidence of multiple rearrangements

This paper reports our attempts to characterize transgene integration sites in transgenic mouse lines generated by the microinjection of large (from 30 to 145 kb) pig DNA fragments encompassing a mammary specific gene, the whey acidic protein gene (WAP). Among the various methods used, the thermal asymmetric interlaced (TAIL-) PCR method allowed us (1) to analyze transgene/genomic borders and internal concatamer junctions for eleven transgenic lines, (2) to obtain sequence information for seven borders, (3) to place three transgenes in the mouse genome, and (4) to obtain sequence data for seven transgene junctions in concatamers. Finally, we characterized various rearrangements in the borders and the inner parts of the transgene. The possibility of such complex rearrangements should be carefully considered when transgenic animals are produced with large genomic DNA fragments.     

A large-scale phylogeny of Synodontis (Mochokidae,Siluriformes) reveals the influence of geological events on continental diversity during the Cenozoic

To explain the spatial variability of fish taxa at a large scale, two alternative proposals are usually evoked. In recent years, the debate has centred on the relative roles of present and historical processes in shaping biodiversity patterns. In Africa, attempts to understand the processes that determine the large scale distribution of fishes and exploration of historical contingencies have been under-investigated given that most of the phylogenetic studies focus on the history of the Great Lakes. Here, we explore phylogeographic events in the evolutionary history of Synodontis (Mohokidae, Siluriformes) over Africa during the Cenozoic focusing on the putative role of historical processes. We discuss how known geological events together with hydrographical changes contributed to shape Synodontis biogeographical history. Synodontis was chosen on the basis of its high diversity and distribution in Africa: it consists of approximately 120 species that are widely distributed in all hydrographic basins except the Maghreb and South Africa. We propose the most comprehensive phylogeny of this catfish genus. Our results provide support for the ‘hydrogeological’ hypothesis, which proposes that palaeohydrological changes linked with the geological context may have been the cause of diversification of freshwater fish deep in the Tertiary. More precisely, the two main geological structures that participated to shape the hydrographical network in Africa, namely the Central African Shear zone and the East African rift system, appear as strong drivers of Synodontis diversification and evolution.     

Loss of Function of Glucocerebrosidase GBA2 Is Responsible for Motor Neuron Defects in Hereditary Spastic Paraplegia

Spastic paraplegia 46 refers to a locus mapped to chromosome 9 that accounts for a complicated autosomal-recessive form of hereditary spastic paraplegia (HSP). With next-generation sequencing in three independent families, we identified four different mutations in GBA2 (three truncating variants and one missense variant), which were found to cosegregate with the disease and were absent in controls. GBA2 encodes a microsomal nonlysosomal glucosylceramidase that catalyzes the conversion of glucosylceramide to free glucose and ceramide and the hydrolysis of bile acid 3-O-glucosides. The missense variant was also found at the homozygous state in a simplex subject in whom no residual glucocerebrosidase activity of GBA2 could be evidenced in blood cells, opening the way to a possible measurement of this enzyme activity in clinical practice. The overall phenotype was a complex HSP with mental impairment, cataract, and hypogonadism in males associated with various degrees of corpus callosum and cerebellar atrophy on brain imaging. Antisense morpholino oligonucleotides targeting the zebrafish GBA2 orthologous gene led to abnormal motor behavior and axonal shortening/branching of motoneurons that were rescued by the human wild-type mRNA but not by applying the same mRNA containing the missense mutation. This study highlights the role of ceramide metabolism in HSP pathology.     

Intratracheally administered titanium dioxide or carbon black nanoparticles do not aggravate elastase-induced pulmonary emphysema in rats

ABSTRACT: BACKGROUND: Titanium dioxide (TiO2) and carbon black (CB) nanoparticles (NPs) have biological effects that could aggravate pulmonary emphysema. The aim of this study was to evaluate whether pulmonary administration of TiO2 or CB NPs in rats could induce and/or aggravate elastase-induced emphysema, and to investigate the underlying molecular mechanisms. METHODS: On day 1, Sprague-Dawley rats were intratracheally instilled with 25 U kg1 pancreatic porcine elastase or saline. On day 7, they received an intratracheal instillation of TiO2 or CB (at 100 and 500 mug) dispersed in bovine serum albumin or bovine serum albumin alone. Animals were sacrificed at days 8 or 21, and bronchoalveolar lavage (BAL) cellularity, histological analysis of inflammation and emphysema, and lung mRNA expression of heme oxygenase-1 (HO-1), interleukin-1beta (IL-1beta), macrophage inflammatory protein-2, monocyte chemotactic protein-1, and matrix metalloprotease (MMP)-1, and -12 were measured. In addition, pulmonary MMP-12 expression was also analyzed at the protein level by immunohistochemistry. RESULTS: TiO2 NPs per se did not modify the parameters investigated, but CB NPs increased perivascular/peribronchial infiltration, and macrophage MMP-12 expression, without inducing emphysema. Elastase administration increased BAL cellularity, histological inflammation, HO-1, IL-1beta and macrophage MMP-12 expression and induced emphysema. Exposure to TiO2 NPs did not modify pulmonary responses to elastase, but exposure to CB NPs aggravated elastase-induced histological inflammation without aggravating emphysema. CONCLUSIONS: TiO2 and CB NPs did not aggravate elastase-induced emphysema. However, CB NPs induced histological inflammation and MMP-12 mRNA and protein expression in macrophages.