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Gif-sur-Yvette, France

Sirami C.,CNRS Center of Evolutionary and Functional Ecology | Sirami C.,South African National Biodiversity Institute | Sirami C.,University of Cape Town | Nespoulous A.,CNRS Center of Evolutionary and Functional Ecology | And 9 more authors.
Landscape and Urban Planning | Year: 2010

Mediterranean landscapes resulted from the complex and ancient interaction of ecosystems and societies. Today they represent one of the world's biodiversity hotspots. These landscapes have a fine-grained mosaic and a high resilience to disturbances. However, during the last century, human pressures have led to new landscape structures and dynamics and an overall decrease in biological diversity. Within a Mediterranean landscape from southern France, we assessed the effects of land use changes on land cover and biodiversity over the last 60 years. The major land use changes involved a substantial decrease in sheep grazing and wood cutting corresponding to the abandonment of 70% of the study area. This resulted in a reduction in land use diversity which was usually high in the Mediterranean. Although land cover in the study area changed gradually (2.2% per year), over 74% changed between 1946 and 2002. This habitat shift had a subsequent impact on species distribution. Apart from amphibians and insects, most species of birds, reptiles, orchids and rare plants that responded positively to these changes were associated with woodlands, while species that responded negatively were associated with open habitats. In the Mediterranean, most rare and endemic species are associated with open habitats and are thus threatened by land abandonment. As a result, land abandonment is contributing to a decrease in local species richness and a decrease in rare and endemic species. Since similar patterns of change have been observed over most of the north-western Mediterranean, land abandonment represents a major threat for biodiversity in the Mediterranean. © 2010.

Bolte S.,Center de | Bolte S.,University Pierre and Marie Curie | Lanquar V.,French National Center for Scientific Research | Lanquar V.,Carnegie Institution for Science | And 6 more authors.
Plant and Cell Physiology | Year: 2011

Plant cell vacuoles are diverse and dynamic structures. In particular, during seed germination, the protein storage vacuoles are rapidly replaced by a central lytic vacuole enabling rapid elongation of embryo cells. In this study, we investigate the dynamic remodeling of vacuolar compartments during Arabidopsis seed germination using immunocytochemistry with antibodies against tonoplast intrinsic protein (TIP) isoforms as well as proteins involved in nutrient mobilization and vacuolar acidification. Our results confirm the existence of a lytic compartment embedded in the protein storage vacuole of dry seeds, decorated by γ-TIP, the vacuolar proton pumping pyrophosphatase (V-PPase) and the metal transporter NRAMP4. They further indicate that this compartment disappears after stratification. It is then replaced by a newly formed lytic compartment, labeled by γ-TIP and V-PPase but not AtNRAMP4, which occupies a larger volume as germination progresses. Altogether, our results indicate the successive occurrence of two different lytic compartments in the protein storage vacuoles of germinating Arabidopsis cells. We propose that the first one corresponds to globoids specialized in mineral storage and the second one is at the origin of the central lytic vacuole in these cells. © 2011 The Author.

Deconinck N.,Free University of Colombia | Deconinck N.,University Pierre and Marie Curie | Dion E.,University Paris Diderot | Yaou R.B.,University Pierre and Marie Curie | And 24 more authors.
Neuromuscular Disorders | Year: 2010

Bethlem myopathy and Ullrich congenital muscular dystrophy are part of the heterogeneous group of collagen VI-related muscle disorders. They are caused by mutations in collagen VI (ColVI) genes (COL6A1, COL6A2, and COL6A3) while LMNA mutations cause autosomal dominant Emery-Dreifuss muscular dystrophy. A muscular dystrophy pattern and contractures are found in all three conditions, making differential diagnosis difficult especially in young patients when cardiomyopathy is absent.We retrospectively assessed upper and lower limb muscle CT scans in 14 Bethlem/Ullrich patients and 13 Emery-Dreifuss patients with identified mutations.CT was able to differentiate Emery-Dreifuss muscular dystrophy from ColVI-related myopathies in selected thigh muscles and to a lesser extent calves muscles: rectus femoris fatty infiltration was selectively present in Bethlem/Ullrich patients while posterior thigh muscles infiltration was more prominently found in Emery-Dreifuss patients. A more severe fatty infiltration particularly in the leg posterior compartment was found in the Emery-Dreifuss group. © 2010 Elsevier B.V.

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