An evolutionary perspective on leaf economics: phylogenetics of leaf mass per area in vascular plants.

In plant leaves, resource use follows a trade-off between rapid resource capture and conservative storage. This "worldwide leaf economics spectrum" consists of a suite of intercorrelated leaf traits, among which leaf mass per area, LMA, is one of the most fundamental as it indicates the cost of leaf construction and light-interception borne by plants. We conducted a broad-scale analysis of the evolutionary history of LMA across a large dataset of 5401 vascular plant species.

[Cellular and molecular effects of the antidepressant hyperforin on brain cells: Review of the literature].

Introduction: Hypericum perforatum is, with Ginkgo biloba, one of the most frequently prescribed medicinal plants in the world. Its popular name, St. John's wort (SJW), is due to the fact that its flowers, yellow, are gathered around the feast of St.

4-Demethylwyosine synthase from Pyrococcus abyssi is a radical-S-adenosyl-L-methionine enzyme with an additional [4Fe-4S](+2) cluster that interacts with the pyruvate co-substrate.

Wybutosine and its derivatives are found in position 37 of tRNA encoding Phe in eukaryotes and archaea. They are believed to play a key role in the decoding function of the ribosome. The second step in the biosynthesis of wybutosine is catalyzed by TYW1 protein, which is a member of the well established class of metalloenzymes called "Radical-SAM.

Inhibition of p-aminobenzoate and folate syntheses in plants and apicomplexan parasites by natural product rubreserine.

Glutamine amidotransferase/aminodeoxychorismate synthase (GAT-ADCS) is a bifunctional enzyme involved in the synthesis of p-aminobenzoate, a central component part of folate cofactors. GAT-ADCS is found in eukaryotic organisms autonomous for folate biosynthesis, such as plants or parasites of the phylum Apicomplexa. Based on an automated screening to search for new inhibitors of folate biosynthesis, we found that rubreserine was able to inhibit the glutamine amidotransferase activity of the plant GAT-ADCS with an apparent IC(50) of about 8 μM.

Yeast ADP/ATP carrier isoform 2: conformational dynamics and role of the RRRMMM signature sequence methionines.

The mitochondrial ADP/ATP carrier, or Ancp, is a member of the mitochondrial carrier family responsible for exchanging ADP and ATP across the mitochondrial inner membrane. ADP/ATP transport involves Ancp switching between two conformational states. These can be analyzed using specific inhibitors, carboxyatractyloside (CATR) and bongkrekic acid (BA).

Conformational dynamics of the bovine mitochondrial ADP/ATP carrier isoform 1 revealed by hydrogen/deuterium exchange coupled to mass spectrometry.

The mitochondrial adenine nucleotide carrier (Ancp) catalyzes the transport of ADP and ATP across the mitochondrial inner membrane, thus playing an essential role in cellular energy metabolism. During the transport mechanism the carrier switches between two different conformations that can be blocked by two toxins: carboxyatractyloside (CATR) and bongkrekic acid. Therefore, our understanding of the nucleotide transport mechanism can be improved by analyzing structural differences of the individual inhibited states.

Association of urinary 15-F2t-isoprostane level with oxygen desaturation and carotid intima-media thickness in nonobese sleep apnea patients.

Obstructive sleep apnea (OSA) is characterized by recurrent apnea during sleep that may unbalance oxidative stress, increasing atherosclerosis. Among oxidative stress markers, 15-F(2t)-isoprostane is considered one of the most sensitive and specific metabolites of lipid peroxidation. To explore the relationship between urinary 15-F(2t)-isoprostane with sleep apnea severity and carotid modifications in nonobese OSA patients, 31 nonobese sleep apnea patients were studied, along with 10 lean subjects without OSA.

New generation sequencers as a tool for genotyping of highly polymorphic multilocus MHC system.

Accurate genotyping of complex systems, such as the major histocompatibility complex (MHC) often requires simultaneous analysis of multiple co-amplifying loci. Here we explore the utility of the massively parallel 454 sequencing method as a universal tool for genotyping complex MHC systems in nonmodel vertebrates. The power of this approach stems from the use of tagged polymerase chain reaction (PCR) primers to identify individual amplicons which can be simultaneously sequenced to the arbitrarily chosen coverage.

Urinary levels of oxidative DNA and RNA damage among workers exposed to polycyclic aromatic hydrocarbons in silicon production: comparison with 1-hydroxypyrene.

Polycyclic aromatic hydrocarbons (PAH) are ubiquitous occupational and environmental pollutants and the urinary excretion of 1-hydroxypyrene (1-OHP) is classically measured for the determination of PAH exposure internal dose. Some of PAH are tumorigenic due to their metabolites ability to generate DNA adducts and oxidative DNA damage through the production of reactive oxygen species during metabolism. 8-hydroxy-7,8-dihydro-2'-deoxyguanosine (8-OHdGuo) is one of the major oxidative DNA lesions and its use as a potential biomarker of genotoxic PAH occupational exposure should be evaluated.

A genome-wide and metabolic analysis determined the adaptive response of Arabidopsis cells to folate depletion induced by methotrexate.

Control of folate homeostasis is essential to sustain the demand for one-carbon (C1) units that are necessary for major biological functions, including nucleotide synthesis and methylation reactions. In this study, we analyzed the genome-wide and metabolic adaptive response of Arabidopsis (Arabidopsis thaliana) cells to folate depletion induced by the antifolate methotrexate. Drug treatment induced a response typical to xenobiotic stress and important changes in folate content and composition.

Shoot-and-Trap: use of specific x-ray damage to study structural protein dynamics by temperature-controlled cryo-crystallography.

Although x-ray crystallography is the most widely used method for macromolecular structure determination, it does not provide dynamical information, and either experimental tricks or complementary experiments must be used to overcome the inherently static nature of crystallographic structures. Here we used specific x-ray damage during temperature-controlled crystallographic experiments at a third-generation synchrotron source to trigger and monitor (Shoot-and-Trap) structural changes putatively involved in an enzymatic reaction. In particular, a nonhydrolyzable substrate analogue of acetylcholinesterase, the "off-switch" at cholinergic synapses, was radiocleaved within the buried enzymatic active site.

Monitoring the capillary-alveolar leakage in an A.R.D.S. model using broncho-alveolar lavage.

Objectives: We developed a modified broncho-alveolar lavage (BAL) technique in order to perform repeated measurements of capillary-alveolar leakage of a macromolecule in oleic acid (OA)-induced lung injury.

Methods: BAL was performed in anesthetized dogs in a closed lung sampling site, using a bronchoscope fitted with an inflatable cuff. Fluorescein-labeled Dextran (FITC-D70) was continuously infused and its concentration measured in plasma and BAL fluid.

New light on methylthiolation reactions.

A novel enzyme, named RimO for ribosomal modification (Anton et al., 2008) catalyzes the methylthiolation of aspartate 88 of the S12 ribosomal protein in Escherichia coli and shows a strong similarity with the iron-sulfur enzyme MiaB involved in the methylthiolation of tRNAs.

The Saccharomyces cerevisiae ADP/ATP carrier-iso 1 cytochrome c fusion protein: one-step purification and functional analysis in vitro.

Genetic expression versus plasmidic overexpression of a functional recombinant fusion protein combining the yeast Saccharomyces cerevisiae mitochondrial ADP/ATP carrier (Anc2p) and the iso-1-cytochrome c (Cyc1p) has been investigated, with the main aim of increasing the polar surface of the carrier to improve its crystallization properties. The gene encoding the his6-tagged fusion protein was expressed in yeast under the control of the regulatory sequences of ScANC2 or under the control of the strong yeast PMA1 promoter. In both cases, the chimeric carrier, Anc2-Cyc1(His6)p, was able to restore growth on a non-fermentable carbon source of a yeast strain devoid of functional ADP/ATP carrier, demonstrating its transport activity.

Molecular, functional, and pathological aspects of the mitochondrial ADP/ATP carrier.

In providing the cell with ATP generated by oxidative phosphorylation, the mitochondrial ADP/ATP carrier plays a central role in aerobic eukaryotic cells. Combining biochemical, genetic, and structural approaches contributes to understanding the molecular mechanism of this essential transport system, the dysfunction of which is implicated in neuromuscular diseases.

Folate synthesis in plants: purification, kinetic properties, and inhibition of aminodeoxychorismate synthase.

pABA (p-aminobenzoate) is a precursor of folates and, besides esterification to glucose, has no other known metabolic fate in plants. It is synthesized in two steps from chorismate and glutamine, the first step being their conversion into glutamate and ADC (4-aminodeoxychorismate). In Escherichia coli, two proteins forming a heterodimeric complex are required for this reaction, but, in plants and lower eukaryotes, a single protein is involved.

Continuous photobleaching in vesicles and living cells: a measure of diffusion and compartmentation.

We present a comprehensive and analytical treatment of continuous photobleaching in a compartment, under single photon excitation. In the very short time regime (t<0.1 ms), the diffusion does not play any role.

Probing structure/affinity relationships for the Plasmodium falciparum hexose transporter with glucose derivatives.

A series of 3-O-substituted glucose derivatives was prepared with alkyl, alkenyl, aromatic and ferrocenic substituents; to vary lipophilicity and hydrogen bonding ethylenedioxy and perfluorinated fragments were also introduced. Apparent affinities for the Plasmodium falciparum hexose transporter (PfHT) were determined after heterologous expression in Xenopus oocytes, with highest affinities for compounds with C8-C13 lipophilic chains. As no derivatives show significant affinity for the mammalian glucose transporter (GLUT1), these structure/affinity assays contribute to design of potent PfHT inhibitors and eventual development of antimalarials.

Conformation-dependent swinging of the matrix loop m2 of the mitochondrial Saccharomyces cerevisiae ADP/ATP carrier.

Structure-function relationships of the membrane-embedded Saccharomyces cerevisiae mitochondrial ADP/ATP carrier were investigated through two independent approaches, namely, limited proteolysis and cysteine labeling. Experiments were carried out in the presence of either carboxyatractyloside (CATR) or bongkrekic acid (BA), two specific inhibitors of the ADP/ATP transport that bind to two distinct conformers involved in the translocation process. The proteolysis approach allowed us to demonstrate (i) that N- and C-terminal extremities of ADP/ATP carrier are facing the intermembrane space and (ii) that the central region of the carrier corresponding to the matrix loop m2 is accessible to externally added trypsin in a conformation-sensitive manner, being cleaved at the Lys163-Gly164 and Lys178-Thr179 bonds in the carrier-CATR and the carrier-BA complexes, respectively.

Angiotensin II induces tyrosine nitration and activation of ERK1/2 in vascular smooth muscle cells.

Angiotensin II (Ang II) induces a prominent and sustained nitration and activation of ERK1/2 in rat vascular smooth muscle cells, both mediated via AT1 receptor. Nitration and activation was also shown for recombinant non-activated extracellular signal-regulated kinase (ERK) and MEK. Nitration and phosphorylation of ERK1/2 by Ang II was significantly inhibited by NAD(P)H inhibitors and scavengers of oxygen and nitrogen reactive species and completely blocked by a selective inducible nitric-oxide synthase inhibitor.

Electrogeneration of a poly(pyrrole)-NTA chelator film for a reversible oriented immobilization of histidine-tagged proteins.

This contribution reports, for the first time, the synthesis and electropolymerization of a pyrrole N-substituted by a nitrilotriacetic acid acting as a chelating center of Cu2+. A step-by-step approach for protein immobilization was developed via the successive coordination of Cu2+ and histidine-tagged proteins. The self-assembly of histidine-tagged glucose oxidase led to the formation of a close-packed enzyme monolayer at the poly(pyrrole) surface, and the reversibility and reproducibility of this affinity process were demonstrated.

Functional characterization and purification of a Saccharomyces cerevisiae ADP/ATP carrier-iso 1 cytochrome c fusion protein.

A recombinant fusion protein combining the mitochondrial ADP/ATP carrier (Anc2p) and the iso-1-cytochrome c (Cyc1p), both from Saccharomyces cerevisiae, has been genetically elaborated with the aim of increasing the polar surface area of the carrier to facilitate its crystallization. The gene encoding the his-tagged fusion protein was expressed in yeast under the control of the regulatory sequences of ScANC2. The chimeric carrier, Anc2-Cyc1(His6)p, was able to restore growth on a non-fermentable carbon source of a yeast strain devoid of functional ADP/ATP carrier, which demonstrated its transport activity.

The two major oligomeric forms of human mannan-binding lectin: chemical characterization, carbohydrate-binding properties, and interaction with MBL-associated serine proteases.

Mannan-binding lectin (MBL) is an oligomeric C-type lectin assembled from homotrimeric structural units that binds to neutral carbohydrates on microbial surfaces. It forms individual complexes with MBL-associated serine proteases (MASP)-1, -2, -3 and a truncated form of MASP-2 (MAp19) and triggers the lectin pathway of complement through MASP-2 activation. To characterize the oligomerization state of the two major MBL forms present in human serum, both proteins were analyzed by mass spectrometry.

Crucial role of two potential cytosolic regions of Nox2, 191TSSTKTIRRS200 and 484DESQANHFAVHHDEEKD500, on NADPH oxidase activation.

Assembly of cytosolic factors p67(phox) and p47(phox) with cytochrome b(558) is one of the crucial keys for NADPH oxidase activation. Certain sequences of Nox2 appear to be involved in cytosolic factor interaction. The role of the D-loop (191)TSSTKTIRRS(200) and the C-terminal (484)DESQANHFAVHHDEEKD(500) of Nox2 on oxidase activity and assembly was investigated.