High-resolution neutron and X-ray diffraction room-temperature studies of an H-FABP-oleic acid complex: study of the internal water cluster and ligand binding by a transferred multipolar electron-density distribution

Crystal diffraction data of heart fatty acid binding protein (H-FABP) in complex with oleic acid were measured at room temperature with high-resolution X-ray and neutron protein crystallography (0.98 and 1.90 Å resolution, respectively). These data provided very detailed information about the cluster of water molecules and the bound oleic acid in the H-FABP large internal cavity. The jointly refined X-ray/neutron structure of H-FABP was complemented by a transferred multipolar electron-density distribution using the parameters of the ELMAMII library. The resulting electron density allowed a precise determination of the electrostatic potential in the fatty acid (FA) binding pocket. Bader's quantum theory of atoms in molecules was then used to study interactions involving the internal water molecules, the FA and the protein. This approach showed H···H contacts of the FA with highly conserved hydrophobic residues known to play a role in the stabilization of long-chain FAs in the binding cavity. The determination of water hydrogen (deuterium) positions allowed the analysis of the orientation and electrostatic properties of the water molecules in the very ordered cluster. As a result, a significant alignment of the permanent dipoles of the water molecules with the protein electrostatic field was observed. This can be related to the dielectric properties of hydration layers around proteins, where the shielding of electrostatic interactions depends directly on the rotational degrees of freedom of the water molecules in the interface.Facultad de Ciencias ExactasInstituto de Física de Líquidos y Sistemas Biológico

High-resolution neutron and X-ray diffraction room-temperature studies of an H-FABP-oleic acid complex: study of the internal water cluster and ligand binding by a transferred multipolar electron-density distribution

Crystal diffraction data of heart fatty acid binding protein (H-FABP) in complex with oleic acid were measured at room temperature with high-resolution X-ray and neutron protein crystallography (0.98 and 1.90 Å resolution, respectively). These data provided very detailed information about the cluster of water molecules and the bound oleic acid in the H-FABP large internal cavity. The jointly refined X-ray/neutron structure of H-FABP was complemented by a transferred multipolar electron-density distribution using the parameters of the ELMAMII library. The resulting electron density allowed a precise determination of the electrostatic potential in the fatty acid (FA) binding pocket. Bader's quantum theory of atoms in molecules was then used to study interactions involving the internal water molecules, the FA and the protein. This approach showed H···H contacts of the FA with highly conserved hydrophobic residues known to play a role in the stabilization of long-chain FAs in the binding cavity. The determination of water hydrogen (deuterium) positions allowed the analysis of the orientation and electrostatic properties of the water molecules in the very ordered cluster. As a result, a significant alignment of the permanent dipoles of the water molecules with the protein electrostatic field was observed. This can be related to the dielectric properties of hydration layers around proteins, where the shielding of electrostatic interactions depends directly on the rotational degrees of freedom of the water molecules in the interface.Facultad de Ciencias ExactasInstituto de Física de Líquidos y Sistemas Biológico

Active Trachoma among Children in Mali: Clustering and Environmental Risk Factors

Active trachoma is not uniformly distributed in endemic areas, and local environmental factors influencing its prevalence are not yet adequately understood. Determining whether clustering is a consistent phenomenon may help predict likely modes of transmission and help to determine the appropriate level at which to target control interventions. In this work, we estimated the magnitude of clustering at different levels and investigated the influence of socio-economic factors and environmental features on active trachoma prevalence among children in Mali (1996–1997 nationwide survey). Clustering revealed significant results at the child, caretaker, household, and village levels. Moreover, beyond some well-established individual risk factors (age between 3 and 5, dirty face, and flies on the face), we found that temperature, sunshine fraction, and presence of rainy days were negatively associated with active trachoma prevalence. This study clearly indicates the importance of directing control efforts both at children with active trachoma as well as those with close contact, and at communities. These results support facial cleanliness and environmental improvements as population-health initiatives to combat blinding trachoma

Transferts d'eau et de nitrate en zone de maraîchage intensif : vallée de la Vistrenque (Gard)

National audienc

Transferts d'eau et de nitrate en zone de maraîchage intensif : vallée de la Vistrenque (Gard)

National audienc

Spatial and temporal variability of nitrate in irrigated salad crops

International audienc

Bilans hydrique et azote a l'echelle parcellaire : variabilite spatiale et consequences methodologiques

* INRA Unite de Science du Sol, Domaine St Paul, Site Agroparc, 84914 Avignon cedex 9 Diffusion du document : INRA Unite de Science du Sol, Domaine St Paul, Site Agroparc, 84914 Avignon cedex 9National audienc

Venous thrombosis of the left ovarian and extension to the renal vein

peer reviewedLa thrombose veineuse ovarienne est une complication rare, mais sérieuse du post-partum. La veine ovarienne droite est impliquée dans 80 % des cas et la veine ovarienne gauche dans moins de 6 % des cas, la thrombose est bilatérale dans 14 % des cas. Le tableau clinique peut être typique avec une douleur abdominale, de la fièvre et une hyperleucocytose, mais peut également se présenter sous forme d’une symptomatologie moins évocatrice, rendant le diagnostic plus difficile. Les complications principales sont l’extension du thrombus à la veine rénale ou la veine cave inférieure, le sepsis et l’embolie pulmonaire. Son diagnostic repose essentiellement sur les techniques d’imagerie, en particulier le scanner et la résonance magnétique dont la sensibilité et la spécificité sont élevées. Le traitement des formes non compliquées comprend une antibiothérapie et des anticoagulants. Les cas de thromboses veineuses ovariennes compliquées nécessitent parfois une prise en charge chirurgicale. Le taux de morbidité et de mortalité peut être réduit par un diagnostic précoce et un traitement adapté. A l’heure actuelle, grâce à l’instauration rapide du traitement approprié, les complications létales sont devenues exceptionnelles.Ovarian vein thrombosis is a rare, but potentially serious postpartum complication. In 80 % of the cases, it occurs on the right side and in less than 6 % on the left side; it is bilateral in 14 % of cases. The usual clinical features include abdominal pain, fever and leucocytosis. However, the diagnosis is often complicated by other non specific signs and symptoms. Ovarian vein thrombosis may cause sepsis, pulmonary thromboembolism, and thrombosis of the inferior vena cava and the renal vein. The diagnosis can be established by CT scan or nuclear magnetic resonance imaging, which has a high sensitivity and specificity. Treatment for the ovarian vein thrombosis includes antibiotics and anticoagulation. The complications can sometimes be surgically managed. Prompt diagnosis and treatment can decrease the morbidity and the mortality. Nowadays, the fatal issue is rare as the appropriate treatment is quickly instaured