Multimodal Imaging Mass Spectrometry to Identify Markers of Pulmonary Arterial Hypertension in Human Lung Tissue Using MALDI-ToF, ToF-SIMS, and Hybrid SIMS.

Pulmonary arterial hypertension (PAH) is a rare and deadly disease affecting roughly 15-60 people per million in Europe with a poorly understood pathology. There are currently no diagnostic tools for early detection nor does a curative treatment exist. The lipid composition of arteries in lung tissue samples from human PAH and control patients were investigated using matrix-assisted laser desorption ionization (MALDI) imaging mass spectrometry (IMS) combined with time-of-flight secondary ion mass spectrometry (TOF-SIMS) imaging.

Purification, Toxicity and Functional Characterization of a New Proteinaceous Mussel Biotoxin from Bizerte Lagoon.

The marine environment is known to be occupied by microorganisms. The potential toxicity of some of these marine microorganisms, that are capable of producing unknown biotoxins, has always been underestimated. Indeed, these biotoxins may be a threat to human health through the consumption of contaminated seafood and fish.

Structural and genomic decoding of human and plant myristoylomes reveals a definitive recognition pattern.

An organism's entire protein modification repertoire has yet to be comprehensively mapped. N-myristoylation (MYR) is a crucial eukaryotic N-terminal protein modification. Here we mapped complete Homo sapiens and Arabidopsis thaliana myristoylomes.

Targeted Profiling of Subproteomes Illuminates Co- and Posttranslationally N-Terminal Myristoylated Proteins.

N-terminal myristoylation, a major eukaryotic protein lipid modification, is difficult to detect in vivo and challenging to predict in silico. We developed a proteomics strategy involving subfractionation of cellular membranes, combined with separation of hydrophobic peptides by mass spectrometry-coupled liquid chromatography to identify the myristoylated proteome. This approach identified a starting pool of 8837 proteins in all analyzed cellular fractions, comprising 32% of the Arabidopsis proteome.

DYRK1A inhibition and cognitive rescue in a Down syndrome mouse model are induced by new fluoro-DANDY derivatives.

Inhibition of DYRK1A kinase, produced by chromosome 21 and consequently overproduced in trisomy 21 subjects, has been suggested as a therapeutic approach to treating the cognitive deficiencies observed in Down syndrome (DS). We now report the synthesis and potent DYRK1A inhibitory activities of fluoro derivatives of 3,5-di(polyhydroxyaryl)-7-azaindoles (F-DANDYs). One of these compounds (3-(4-fluorophenyl)-5-(3,4-dihydroxyphenyl)-1H-pyrrolo[2,3-b]pyridine, 5a) was selected for in vivo studies of cognitive rescuing effects in a standard mouse model of DS (Ts65Dn line).

An Integrative Approach to Decipher the Chemical Antagonism between the Competing Endophytes Paraconiothyrium variabile and Bacillus subtilis.

An integrative approach combining traditional natural products chemistry, molecular networking, and mass spectrometry imaging has been undertaken to decipher the molecular dialogue between the fungus Paraconiothyrium variabile and the bacterium Bacillus subtilis, which were isolated as endophytes from the conifer Cephalotaxus harringtonia and are characterized by a strong and mutual antibiosis. From this study, we highlight that bacterial surfactins and a fungal tetronic acid are involved in such competition and that the fungus is able to hydrolyze surfactins to fight against the bacterial partner.

Affinity labelling in situ of the bL12 protein on E. coli 70S ribosomes by means of a tRNA dialdehyde derivative.

In this report, we have used periodate-oxidized tRNA (tRNAox) as an affinity laleling reagent to demonstrate that: (i) the bL12 protein contacts the CCA-arm of P-site bound tRNA on the Escherichia coli 70S ribosomes; (ii) the stoichiometry of labelling is one molecule of tRNAox bound to one polypeptide chain of endogenous bL12; (iii) cross-linking in situ of bL12 with tRNAox on the ribosomes provokes the loss of activity; (iv) intact tRNA protects bL12 in the 70S ribosomes against cross-linking with tRNAox; (v) both tRNAox and pyridoxal 5'-phosphate (PLP) compete for the same or for proximal cross-linking site(s) on bL12 inside the ribosome; (vi) the stoichiometry of cross-linking of PLP to the recombinant E. coli bL12 protein is one molecule of PLP covalently bound per polypeptide chain; (vii) the amino acid residue of recombinant bL12 cross-linked with PLP is Lys-65; (viii) Lys-65 of E. coli bL12 corresponds to Lys-53 of eL42 which was previously shown to cross-link with P-site bound tRNAox on human 80S ribosomes in situ; (ix) finally, E.

Mammalian frataxin directly enhances sulfur transfer of NFS1 persulfide to both ISCU and free thiols.

Friedreich's ataxia is a severe neurodegenerative disease caused by the decreased expression of frataxin, a mitochondrial protein that stimulates iron-sulfur (Fe-S) cluster biogenesis. In mammals, the primary steps of Fe-S cluster assembly are performed by the NFS1-ISD11-ISCU complex via the formation of a persulfide intermediate on NFS1. Here we show that frataxin modulates the reactivity of NFS1 persulfide with thiols.

Isolation, purification and functional characterization of alpha-BnIA from Conus bandanus venom.

We report the isolation and characterization by proteomic approach of a native conopeptide, named BnIA, from the crude venom of Conus bandanus, a molluscivorous cone snail species, collected in the South central coast of Vietnam. Its primary sequence was determined by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry using collision-induced dissociation and confirmed by Edman's degradation of the pure native fraction. BnIA was present in high amounts in the crude venom and the complete sequence of the 16 amino acid peptide was the following GCCSHPACSVNNPDIC*, with C-terminal amidation deduced from Edman's degradation and theoretical monoisotopic mass calculation.

Agar-supported cultivation of Halorubrum sp. SSR, and production of halocin C8 on the scale-up prototype Platotex.

Halorubrum sp. SSR was isolated from a solar saltern in Algeria. The strain exhibited a high antibiotic activity against the indicator strain Natronorubrum aibiense G23, and the bioactive compound showed thermal, acid and alkali stability.

Optimization and validation of a label-free MRM method for the quantification of cytochrome P450 isoforms in biological samples.

Cytochromes P450 (CYPs) play critical roles in oxidative metabolism of many endogenous and exogenous compounds. Protein expression levels of CYPs in liver provide relevant information for a better understanding of the importance of CYPs in pharmacology and toxicology. This work aimed at establishing a simple method to quantify six CYPs (CYP3A4, CYP3A5, CYP1A2, CYP2D6, CYP2C9, and CYP2J2) in various biological samples without isotopic labeling.

Toxic c17-sphinganine analogue mycotoxin, contaminating tunisian mussels, causes flaccid paralysis in rodents.

Severe toxicity was detected in mussels from Bizerte Lagoon (Northern Tunisia) using routine mouse bioassays for detecting diarrheic and paralytic toxins not associated to classical phytoplankton blooming. The atypical toxicity was characterized by rapid mouse death. The aim of the present work was to understand the basis of such toxicity.

High accuracy mass spectrometry comparison of Conus bandanus and Conus marmoreus venoms from the South Central Coast of Vietnam.

Cone snail (genus Conus) venoms provide a rich source of small bioactive peptides known as conopeptides or conotoxins, which are highly interesting in pharmacological studies for new drug discovery. Conus species have evolved expressing a variety of conopeptides, adapted to the biological targets of their own specific preys at their living environments. Therefore, the potential proteomic evaluation of Conus venom components, poorly studied, is of great interest.

Identification and functional characterization of a novel α-conotoxin (EIIA) from Conus ermineus.

Nicotinic acetylcholine receptors (nAChRs) are one of the most important families in the ligand-gated ion channel superfamily due to their involvement in primordial brain functions and in several neurodegenerative pathologies. The discovery of new ligands which can bind with high affinity and selectivity to nAChR subtypes is of prime interest in order to study these receptors and to potentially discover new drugs for treating various pathologies. Predatory cone snails of the genus Conus hunt their prey using venoms containing a large number of small, highly structured peptides called conotoxins.

A metabolic prototype for eliminating tryptophan from the genetic code.

We set out to reduce the chemical constitution of a living organism to 19 amino acids. A strain was constructed for reassigning the tryptophan codon UGG to histidine and eliminating tryptophan from Escherichia coli. Histidine codons in the gene for an essential enzyme were replaced with tryptophan codons and the restoration of catalytic activity by missense suppressor His-tRNA bearing a CCA anticodon was selected.

Immunoproteomic analysis of potentially severe non-graft-versus-host disease hepatitis after allogenic bone marrow transplantation.

Unlabelled: The development of potentially severe non-graft-versus-host disease (GVHD) hepatitis resembling autoimmune hepatitis (AIH) has been reported after bone marrow transplantation (BMT). The aim of this study was to better characterize this form of hepatitis, particularly through the identification of autoantigens recognized by patient sera. Five patients who received an allogeneic BMT for the treatment of hematological diseases developed liver dysfunction with histological features suggestive of AIH.

Solid-phase hexapeptide ligand libraries open up new perspectives in the discovery of biomarkers in human plasma.

Background: Pre-treatment of plasma with hexapeptide ligand libraries prior to proteomic analysis is well documented. However, the maintenance of biomarker abundance throughout the different pre-analytical steps is required for a potential application of differential proteomics in clinical studies.

Methods: We combined the use of an amino-terminal hexapeptide ligand library and its carboxyl-terminal version with a sequential elution strategy of the proteins/peptides bound to the beads, followed by either mass spectrometry or 2D electrophoresis analyses.

A region within the C-terminal domain of Ure2p is shown to interact with the molecular chaperone Ssa1p by the use of cross-linkers and mass spectrometry.

The propagation of yeast prion phenotypes is highly dependent on molecular chaperones. We previously demonstrated that the molecular chaperone Ssa1p sequesters Ure2p in high molecular weight, assembly incompetent oligomeric species. We also determined the affinity of Ssa1p for Ure2p, and its globular domain.

Analysis of human C1q by combined bottom-up and top-down mass spectrometry: detailed mapping of post-translational modifications and insights into the C1r/C1s binding sites.

C1q is a subunit of the C1 complex, a key player in innate immunity that triggers activation of the classical complement pathway. Featuring a unique structural organization and comprising a collagen-like domain with a high level of post-translational modifications, C1q represents a challenging protein assembly for structural biology. We report for the first time a comprehensive proteomics study of C1q combining bottom-up and top-down analyses.

The human large subunit ribosomal protein L36A-like contacts the CCA end of P-site bound tRNA.

Periodate-oxidized tRNA (tRNAox), the 2',3'-dialdehyde derivative of tRNA, was used as a zero-length active site-directed affinity labeling reagent, to covalently label proteins at the binding site for the 3'-end of tRNA on human 80S ribosomes. When human 80S ribosomes were reacted with tRNA(Asp)ox positioned at the P-site, in the presence of an appropriate 12 mer mRNA, a set of two tRNAox-labeled ribosomal proteins (rPs) was observed. The majorily labeled protein was identified as the large subunit rP L36a-like (RPL36AL) by means of mass spectrometry.

In situ localisation and quantification of surfactins in a Bacillus subtilis swarming community by imaging mass spectrometry.

Surfactins are a family of heptacyclopeptides in which the C-terminal carbonyl is linked with the beta-hydroxy group of a fatty acid acylating the N-terminal function of a glutamic acid residue. The fatty acyl chain is 12-16 carbon atoms long. These compounds, which are secreted by the Gram-positive bacterium Bacillus subtilis in stationary phase in liquid cultures, play an important role in swarming communities on the surface of agar media in the formation of dendritic patterns.

Large-scale study of phosphoproteins involved in long-term potentiation in the rat dentate gyrus in vivo.

The mechanisms underlying the induction of synaptic plasticity and the formation of long-term memory involve activation of cell-signalling cascades and protein modifications such as phosphorylation and dephosphorylation. Based on a protein candidate strategy, studies have identified several protein kinases and their substrates, which show an altered phosphorylation state during the early phases of long-term potentiation (LTP), yet only a limited number of synaptic phosphoproteins are known to be implicated in LTP. To identify new phosphoproteins associated with LTP, we have undertaken a proteomic study of phosphoproteins at different time points following the induction of LTP in the dentate gyrus in vivo (0, 15 and 90 min).