Improving the Potency of N-Aryl-2,5-dimethylpyrroles against Multidrug-Resistant and Intracellular Mycobacteria

A series of N-phenyl-2,5-dimethylpyrrole derivatives, designed as hybrids of the antitubercular agents BM212 and SQ109, have been synthesized and evaluated against susceptible and drug-resistant mycobacteria strains. Compound 5d, bearing a cyclohexylmethylene side chain, showed high potency against M. tuberculosis including MDR-TB strains at submicromolar concentrations. The new compound shows bacteriostatic activity and low toxicity and proved to be effective against intracellular mycobacteria too, showing an activity profile similar to isoniazid

Directed Evolution of an Artificial Imine Reductase

Artificial metalloenzymes, resulting from incorporation of a metal cofactor within a host protein, have received increasing attention in the last decade. The directed evolution is presented of an artificial transfer hydrogenase (ATHase) based on the biotin-streptavidin technology using a straightforward procedure allowing screening in cell-free extracts. Two streptavidin isoforms were yielded with improved catalytic activity and selectivity for the reduction of cyclic imines. The evolved ATHases were stable under biphasic catalytic conditions. The X-ray structure analysis reveals that introducing bulky residues within the active site results in flexibility changes of the cofactor, thus increasing exposure of the metal to the protein surface and leading to a reversal of enantioselectivity. This hypothesis was confirmed by a multiscale approach based mostly on molecular dynamics and protein-ligand dockings

Tackling the antibiotic resistance in tuberculosis: Synthesis and biological evaluation of novel antitubercular agents and development of novel methodologies for the synthesis of heterocycles

Mycobacterium tuberculosis (Mtb), the etiological agent of Tuberculosis (TB) is developing new multi drug-resistant (MDR) and extensively drug-resistant (XDR) strains to the current drugs used in therapy. Of particular concern the wide spreading of tuberculosis, the high rate of development of resistance, and the high mortality of the patients due to the lack of effective therapy against TB infections. In order to face this problem, two series of novel compounds were designed, synthesised and evaluated against a panel of mycobacterial strains. The first series of compounds includes analogues of the third line drug thioridazine (TZ). TZ is a known antipsychotic drug belonging to the phenothiazine drug group, which showed good activity against MDR-TB infections but causes severe side effects which limit its use in therapy. Among the first series of compounds, five new compounds showed anti-tubercular activity similar or higher than TZ. Moreover, two derivatives showed potent inhibition towards the whole-cell drug efflux pump activity of mycobacteria comparable to that of verapamil, and turning to be promising multi-drug resistance reversal agents. A second series of compounds consist of small molecules which have originally been designed as hybrids of the anti-tubercular drugs BM212 and SQ109. Computational studies revealed a perfect superposition of the structures of SQ109 and BM212 and showed that the two drugs share common features. Five of the resulting compounds showed micromolar anti-tubercular activity on pathogenic TB. Two of them proved to be highly active also against multi-drug resistant clinical isolates and one of these also showed minimal eukaryotic cell toxicity, and therefore would be an excellent lead candidate for preclinical trials. In parallel to the identification of novel compounds active against mycobacteria, new synthetic methodologies for the synthesis of antitubercular heterocyclic scaffolds have been developed. In particular two approaches for the synthesis of pyrrole compounds were developed. Both procedures involve an olefin or enyne metathesis reaction as a key step. The first approach involves the synthesis of 1,2,3-substituted pyrroles, through a tandem enyne cross metathesis-cyclization reaction of propargylamines with ethyl-vinyl ether. The reaction is rapid, procedurally simple and represents a facile entry to the synthetically challenging 4,5-unsubstituted pyrroles. The second methodology allows the synthesis of substituted pyrroles from diallyl-amines via a chemo-enzymatic cascade based on the combination of olefin metathesis together with monoamine oxidase (MAO) biocatalysts. These reactions were carried out in aqueous media and mild temperature leading to the formation of substituted pyrroles in a single step and in high yields

Unveiling the Biocatalytic Aromatizing Activity of Monoamine Oxidases MAO-N and 6-HDNO:Development of Chemoenzymatic Cascades for the Synthesis of Pyrroles

A chemoenzymatic cascade process for the sustainable production of pyrroles has been developed. Pyrroles were synthesized by exploiting the previously unexplored aromatizing activity of monoamine oxidase enzymes (MAO-N and 6-HDNO). MAO-N/6-HDNO whole cell biocatalysts are able to convert 3-pyrrolines into pyrroles under mild conditions and in high yields. Moreover, MAO-N can work in combination with the ruthenium Grubbs catalyst, leading to the synthesis of pyrroles from diallylamines/-anilines in a one-pot cascade metathesis–aromatization sequence

Microwave-assisted domino reactions of propargylamines with isothiocyanates: selective synthesis of 2-aminothiazoles and 2-amino-4-methylenethiazolines

A simple and versatile microwave-assisted protocol for the synthesis of 2-aminothiazoles has been developed. The domino reaction of propargylamines and isothiocyanates in the presence of catalytic PTSA leads to the selective synthesis of 2-aminothiazoles at temperatures above 130 °C and in a few minutes. The same reaction carried out at lower temperatures leads to the formation of the tautomeric 2-amino-4-methylenethiazolines

Méthodes statistiques pour la détection de QTL (nouveaux développements et applications chez le canard mulard)

La recherche de QTL par régression des phénotypes sur les probabilités de transmission (modèle Haley-Knott) est une méthode très largement utilisée quand on dispose de grandes familles phénotypées par des caractères gaussiens. L'objectif de cette thèse d'un point de vue méthodologique, est de proposer une méthode de détection de QTL qui prend en compte des effectifs de familles petits d'une part, et l'existence de caractères discrets d'autre part. Ainsi, nous proposons, pour répondre à la première question, une approche de détection de QTL intégrant dans le calcul du mérite génétique des individus marqués, les performances calculées sur n générations de descendants. L'obtention d'un mérite génétique dérégressé comme substitut de phénotypes, proposé notamment par Weller et al (1990) et Tribout et al (2008), est donc généralisée. Ensuite, sont présentés les résultats de comparaisons d'un modèle supposant la normalité des données à un modèle à seuils faisant l'hypothèse d'une distribution continue sous jacente à la distribution observée dans la détection de QTL des caractères discrets. Nous démontrons ici que le modèle discret est plus précis et plus puissant quand le caractère étudié possède trois modalités distribuées de façon déséquilibrée dans la population.Dans la deuxième partie de la thèse, l'analyse des données du protocole GENECAN a été réalisée. Il s'agit d'identifier les régions du génome ou locus à caractère quantitatif (QTL), associées à des caractères d'intérêt mesurés sur des canards mulards gavés. Le canard mulard est un hybride interspécifique obtenu par croisement d'une cane commune (Anas platyrhynchos) et d'un canard de Barbarie (Cairina moschata). Trois cents quarante deux canes communes conçues en back-cross (BC) ont été générées par croisement d'une lignée de canard Kaiya et d'une lignée de canard Pékin lourd. Ces femelles BC ont été accouplées avec des canards de Barbarie pour produire 1600 canards mulards sur lesquels sont effectuées des mesures de croissance, de métabolisme au cours de la période de croissance et du gavage, d'aptitude au gavage et de qualités du magret et du foie gras. La valeur phénotypique des femelles BC marquées a été estimée, pour chaque caractère, comme étant la valeur moyenne des phénotypes de sa progéniture et pondérée par un coefficient de détermination (CD) fonction du nombre de descendants et de l'héritabilité du caractère étudié. Une carte génétique de 91 marqueurs microsatellites réparties sur 16 groupes de liaison (GL) et couvrant un total de 778 cM a été utilisée. Dans le cadre de l'analyse uni-caractère, vingt-deux QTL significatifs à 1% au niveau du chromosome ont été cartographiés. Ces QTLs sont pour la plupart impliqués dans la variabilité de la qualité du magret et du foie gras. Les zones chromosomiques d'intérêt, identifiées dans le cadre de cette étude devront dans le futur, être densifiées en marqueurs pour faire l'objet d'une cartographie fine.QTL detection using the regression of phenotypes on transmission probability is largely used when large families phenotyped for Gaussian trait are available. The aim of this thesis from a methodological point of view, is to propose a method for detection of QTL that takes into account the small number of families on the one hand, and the existence of discrete traits on the other. Thus, we propose to answer the first question, an QTL detection approach, integrating in the calculation of genetic merit of genotyped individuals, the performances calculated over n generations of descendants. The use of a de-regressed proof' as a phenotype to be analysed, proposed by Weller et al. (1990) and Tribout et al. (2008) is generalized. Next, we present the results of comparisons of a model assuming normality of the data to a thresholds model assuming a continuous distribution underlying the observed distribution in the QTL detection of discrete traits. Here we demonstrate that the discrete model is more accurate and more powerful when the studied trait has three modalities distributed unevenly in the population.In the second part of the thesis, the data analysis of GENECAN protocol was performed. This is to identify genomic regions or quantitative trait locus (QTL) associated with interest traits measured on over-feed mule ducks. The mule duck is an hybrid duck from a female Common duck (Anas Platyrhynchos) and a Muscovy drake (Cairina moschata). Three hundred forty two common ducks designed by back-cross (BC) were generated by crossing a line of Kaiya duck and a heavy line of Pekin duck. These BC females were mated with Muscovy ducks to produce 1600 mules ducks which undergo measures of growth, metabolism during the growth and over-feeding periods, over-feeding, of breast muscle and fatty liver qualities. The phenotypic value of genotyped BC females was estimated for each trait as the average phenotypes of their offspring and weighted by a coefficient of determination (CD) function on the number of offspring and heritability of the studied trait. The genetic map comprised 91 microsatellite markers aggregated into 16 linkage groups (LG) and representing 778 cM. For the uni-trait analysis, twenty-two QTL significant at 1% threshold in chromosome-wide have been mapped. These QTLs are mostly involved in the variability of the breast muscle and fatty liver qualities. Chromosomal regions of interest identified in the framework of this study should be in the future be densified to markers to do the fine mapping.PARIS-AgroParisTech Centre Paris (751052302) / SudocSudocFranceF

Magnesium profile in autism.

The aim of the present study was to determine and compare plasma and erythrocyte concentrations of magnesium in 12 autistic children (10 boys, 2 girls), 17 children with other autistic spectrum disorders (14 boys, 3 girls), 5 girls with classic Rett syndrome, and 14 normal children (7 boys, 7 girls) of the same age. No differences in intracellular Mg were found between controls and pathological subjects; however, autistic children and children with other autistic spectrum disorders had significantly lower plasma concentrations of Mg than normal subjects (p=0.013 and p=0.02, respectively). Although our study population was small, we conclude that children with autistic spectrum disorders require special dietary management. If these cases are diagnosed at an early stage, they can be helped through diet

A microwave-assisted multicomponent protocol for the synthesis of benzofuran-2-carboxamides

A fast, versatile and practical microwave-assisted multicomponent protocol for the synthesis of substituted benzofuran-2-carboxamides has been developed. The present method proved to be effective on a series of commercially available amines, 2′-hydroxyacetophenones, aldehydes, and benzonitriles and could be exploited in drug-discovery campaigns for the rapid identification of biologically active hit compounds