Chromium oxidation state imaging in mammalian cells exposed in vitro to soluble or particulate chromate compounds.

Hexavalent chromium compounds are known carcinogens for the respiratory tract in humans. The mechanism of cell transformation by hexavalent chromium compounds is not fully understood although a role for intracellular reduction is sought. The aim of this study was to determine the distribution of Cr valence states in human cells after in vitro exposure to soluble or particulate chromium compounds.

Homology model of the rainbow trout estrogen receptor (rtERalpha) and docking of endocrine disrupting chemicals (EDCs).

A model for rainbow trout (Oncorhynchus mykiss) estrogen receptor (rtERa) was built by homology with the human estrogen receptor (hERa). A high level of sequence conservation between the two receptors was found with 64% and 80% of identity and similarity, respectively. Selected endocrine disrupting chemicals were docked into the ligand binding domain (LBD) of rtERa and the corresponding free binding energies Delta(DeltaG(bind)) values were calculated.

Structural e-bioinformatics and drug design.

Nowadays the in silico scenario for drug design is totally dependent on structural biology and structural bioinformatics. A myriad of free bioinformatics applications and services have been posted on the web. This mini-review mentions web sites that are useful in structure-based drug design.

Effect of substrate temperature on morphology and electrochemical performance of radio frequency magnetron sputtered lithium nickel vanadate films used as negative electrodes for lithium microbatteries.

Lithium nickel vanadate thin films were prepared by radio frequency magnetron sputtering at various substrate temperatures (Ts). These thin films have been investigated as anode electrode material in the use of microbatteries. Films were characterized by Rutherford backscattering spectroscopy, nuclear reaction analysis, Auger electron spectroscopy, glancing-incidence X-ray diffraction analysis, Raman spectroscopy, scanning electron microscopy, atomic force microscopy, and high-resolution transmission electron microscopy techniques.

Interaction between emotion and memory: importance of mammillary bodies damage in a mouse model of the alcoholic Korsakoff syndrome.

Chronic alcohol consumption (CAC) can lead to the Korsakoff syndrome (KS), a memory deficiency attributed to diencephalic damage and/or to medial temporal or cortical related dysfunction. The etiology of KS remains unclear. Most animal models of KS involve thiamine-deficient diets associated with pyrithiamine treatment.

Cyclin-dependent kinase (CDK) inhibitors regulate the CDK-cyclin complex activities in endoreduplicating cells of developing tomato fruit.

The jelly-like locular (gel) tissue of tomato fruit is made up of large thin-walled and highly vacuolized cells. The development of the gel tissue is characterized by the arrest of mitotic activities, the inhibition of cyclin-dependent kinase A (CDKA) activity, and numerous rounds of nuclear DNA endoreduplication. To decipher the molecular determinants controlling these developmental events, we investigated the putative involvement of CDK inhibitors (p27(Kip)-related proteins, or KRPs) during the endoreduplication process.

Friction between two weakly adhering boundary lubricated surfaces in water.

The sliding of adhesive surfactant-bearing surfaces was studied with a surface forces apparatus nanotribometer. When the surfaces are fully immersed in an aqueous solution, the dynamic behavior is drastically different and more varied than under dry conditions. In solution, the shear stress exhibits at least five different velocity regimes.

Impaired cognitive performance in rats after complete epithalamus lesions, but not after pinealectomy alone.

In the midbrain, the epithalamus comprises the habenular nuclei and the pineal gland. Based on evidence including imaging studies in schizophrenia patients, several investigators have postulated that dysfunction of this structure is causally involved in symptoms of schizophrenia. Recently, we showed that bilateral habenula lesions in the rat induced some schizophrenia-like behavioural changes, namely memory and attention impairments, but unaltered social interaction in a brief encounter and prepulse inhibition (PPI) of the startle reflex.

Structural trends and chemical bonding in Te-doped silicon clathrates.

The recently discovered tellurium-doped silicon clathrates, Te7+xSi20-x and Te16Si38, both low- and high-temperature forms (cubic and rhombohedral, respectively), exhibit original structures that are all derived from the parent type I clathrate G8Si46 (G = guest atom). The similarities and differences between the structures of these compounds and that of the parent one are analyzed and discussed on the basis of charge distribution and chemical bonding considerations. Because of the particular character of the Te atom, these compounds appear to be at the border between the clathrate and polytelluride families.

One-year monitoring survey of organic compounds (PAHs, PCBs, TBT), heavy metals and biomarkers in blue mussels from the Arcachon Bay, France.

Marine mussels Mytilus sp. were transplanted on a monthly basis in cages over one year to oyster farms and harbours in the Arcachon Bay (France) in order to assess the water quality of the bay. Contaminant levels (organotin compounds, trace metals, PCBs and PAHs) were measured in tissues of transplanted mussels and mussels from a reference station, along with physiological parameters of the mussels (condition indexes, lipid content and dry weight).

Effects of ibotenic acid lesions of the mediodorsal thalamus on memory: relationship with emotional processes in mice.

The effects of ibotenic acid lesions of the mediodorsal nucleus of the thalamus (MD) on memory and fear reactivity in mice were studied. In the first experiment, MD subjects were submitted to a behavioral design allowing to study the relationship between memory and anxiety [Krazem A, Borde N, Beracochea D. Effects of diazepam and beta-CCM on working memory in mice: relationship with emotional reactivity.

A radio frequency electric current enhances antibiotic efficacy against bacterial biofilms.

Bacterial biofilms are notably resistant to antibiotic prophylaxis. The concentration of antibiotic necessary to significantly reduce the number of bacteria in the biofilm matrix can be several hundred times the MIC for the same bacteria in a planktonic phase. It has been observed that the addition of a weak continuous direct electric current to the liquid surrounding the biofilm can dramatically increase the efficacy of the antibiotic.

Age-dependent effects of serotonin-1A receptor gene deletion in spatial learning abilities in mice.

The serotonin (5-hydroxytryptamine, 5-HT) receptor 1A is involved in many physiological functions, including the regulation of learning and memory by acting either as an autoreceptor located on 5-HT neurons (raphe nuclei) or as a heteroreceptor on non-5-HT neurons, mainly in the hippocampal formation. To investigate whether the effects of 5-HT via 5-HT1A receptors on learning are age-sensitive, we evaluated the performance of young-adult (3 months old) and aged (22 months old) 5-HT1A knockout (KO) mice and their homologous wild types (WT) in the hippocampal-dependent spatial reference memory version of the Morris water maze. We demonstrated that young-adult 5-HT1AKO mice exhibit an impairment in learning and retention of the spatial task, as compared to WT mice, without showing any sign of change in their sensori-motor and locomotor abilities or motivation.

Interaction between the nature of the information and the cognitive requirement of the task in problem solving in mice.

The Morris water maze and the radial-arm maze are two of the most frequently employed behavioral tasks used to assess spatial memory in rodents. In this study, we describe two new behavioral tasks in a radial-arm water maze enabling to combine the advantages of the Morris water maze and the radial-arm maze. In both tasks, spatial and nonspatial learning was assessed and the only task parameter that varied was the nature of the information available which was either spatial (various distal extra-maze cues) or nonspatial (visual intra-maze patterns).

Behavior of adhesive boundary lubricated surfaces under shear: effect of grafted diblock copolymers.

The shear behavior and the normal interaction between mica surfaces covered by surfactant or surfactant-polymer mixtures were studied with a Surface Forces Apparatus (SFA) nanotribometer. If the surfaces are compressed while fully immersed in an aqueous surfactant solution that adsorbs in the form of flat bilayers, hemifusion can be induced. When the hemifused surfaces are subject to shear, at least five different dynamic regimes can be recognized.

Quantitative metabolic profiling by 1-dimensional H-NMR analyses: application to plant genetics and functional genomics.

Metabolic profiling by 1-dimensional (1-D) H-nuclear magnetic resonance (NMR) was tested for absolute quantification of soluble sugars, organic acids, amino acids and some secondary metabolites in fruit, roots and leaves. The metabolite responsible for each peak of the H-NMR spectra was identified from spectra of pure compounds. Peak identity was confirmed by the addition of a small amount of commercially-available pure substance.

Unprecedented polymerization of epsilon-Caprolactone initiated by a single-site lanthanide borohydride complex, [Sm(eta-C5Me5)2(BH4)(thf)]: mechanistic insights.

The monoborohydride lanthanide complex [Sm(Cp*)2(BH4)(thf)] (1a) (Cp* = eta-C5Me5), has been successfully used for the controlled ring-opening polymerization of epsilon-caprolactone (epsilon-CL). The organometallic samarium(III) initiator 1 a produces, in quantitative yields, alpha,omega-dihydroxytelechelic poly(epsilon-caprolactone) displaying relatively narrow polydispersity indices (<1.3) within a short period of time (30 min).

Sites of neocortical reorganization critical for remote spatial memory.

The hippocampus is crucial for spatial memory formation, yet it does not store long-lasting memories. By combining functional brain imaging and region-specific neuronal inactivation in mice, we identified prefrontal and anterior cingulate cortices as critical for storage and retrieval of remote spatial memories [correction]. Imaging of activity-dependent genes also revealed an involvement of parietal and retrosplenial cortices during consolidation of remote memory.

The effects of decanted sediments on embryogenesis in oysters (Crassostrea gigas).

Sediments act as sinks for contaminants of natural and anthropogenic origin, constituting a risk to the living organisms. In this study, sediments were collected from three sites on the coast of southwest France. The objective of this research was to determine the effects of sediments on embryonic development of bivalves and to identify precisely when the contaminants affect the embryos and induce them to develop in an abnormal way.

Effects of ibotenic acid lesions of the dorsal hippocampus on contextual fear conditioning in mice: comparison with mammillary body lesions.

The goals of the present study were to determine if ibotenic acid lesions of the dorsal hippocampus (dHPC) or of mammillary body (MB) of the hypothalamus would induce similar contextual conditioning deficit in a fear-conditioning paradigm, previously developed in mice [Eur. J. Neurosci.

BetaCCM but not physostigmine enhancement of memory retrieval depends on emotional processes in mice.

Rationale: The effects of methyl beta-carboline-3-carboxylate (betaCCM, an inverse agonists of GABA/benzodiazepine receptors) or physostigmine (a cholinesterase inhibitor) on retrieval processes and relationships with anxiety have been only marginally studied.

Objective: This study investigates in mice the effects of acute betaCCM or physostigmine injections on retrieval of previously acquired discriminations involving distinct contextual cues (serial contextual discrimination; SCD) in a four-hole-board. Animals submitted to SCD were also evaluated for emotional reactivity in an elevated-plus maze.

e-molecular shapes and properties.

Due to recent computer technology advances, shape analysis has gained importance in all domains. In drug design and proteomics, molecular surfaces (van der Waals surface, solvent accessible surface, solvent excluded surface, polar surface area, electron density surface, separating surface, etc.), buried surfaces (gap, cleft, cavity, etc.

Microchemical element imaging of yeast and human cells using synchrotron X-ray microprobe with Kirkpatrick-Baez optics.

Trace element imaging and speciation analysis in cells and subcellular compartments is a challenging and important objective for modern analytical chemistry in order to better understand the biological chemistry of essential and toxic elements. A focusing system based on Kirkpatrick-Baez design optics mounted on a synchrotron radiation scanning X-ray microscope has been developed at the ESRF and was used for trace element quantitative imaging in single cells. The focused microbeam (1.

Age-dependent effects of moderate chronic ethanol administration on different forms of memory expression in mice.

A large number of studies have investigated the effects of chronic ethanol administration (CEA) on performance in different types of learning and memory tasks in adult rodents. As a general rule, CEA has been reported to impair performance, although this depends both on the condition of administration (e.g.

Spatial learning in the 5-HT1B receptor knockout mouse: selective facilitation/impairment depending on the cognitive demand.

Age-related memory decline is associated with a combined dysfunction of the cholinergic and serotonergic systems in the hippocampus and frontal cortex, in particular. The 5-HT1B receptor occupies strategic cellular and subcellular locations in these structures, where it plays a role in the modulation of ACh release. In an attempt to characterize the contribution of this receptor to memory functions, 5-HT1B receptor knockout (KO) mice were submitted to various behavioral paradigms carried out in the same experimental context (water maze), which were aimed at exposing mice to various levels of memory demand.