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Fluorinated systems are defined by unique properties that offer advantages in drug delivery, material synthesis and industrial applications. In comparison to their hydrocarbon counterparts, the design of fluorinated solutes for tailored applications is limited by the inability to predict the effect of fluorination on phase behavior. This work examines and interprets the influence of fluorination on the phase behavior of fluorinated solutes and surfactants, with emphasis on their impact on vesicle bilayers. Thermodynamic partitioning of functionalized series of fluorinated and hydrocarbon nicotinate prodrugs fashioned to promote solubility in a fluorocarbon solvent (perfluorooctyl bromide; PFOB) is measured. Predictive approaches are also employed to describe partitioning of these nicotinates between immiscible phases relevant to drug delivery. The findings reveal no strong correlation of the partitioning trends with biological markers of cytotoxicity and prodrug uptake for PFOB mediated delivery. However, partitioning in model membranes (liposomes), which, increases with the hydrophobicity of the perhydrocarbon nicotinates, suggests incorporation in a cellular matrix is chain length dependent. The impact of incorporating fluorinated surfactants in catanionic vesicles, which form spontaneously in dilute aqueous solutions and serve as potential substitutes to conventional meta-stable liposome-based vesicles, is studied. Much larger isotropic vesicle regions are observed in the phase map of the partially fluorinated catanionic surfactant pair, cetylpyridinium bromide/ sodium perfluorooctanoate (CPB/SPFO) than in fully fluorinated HFDPC (1,1,2,2,-tetrahydroperfluorododecyl pyridinium chloride )/SPFO. Fluorescence probing of the vesicle bilayers suggest more fluid bilayers in CPB/SPFO than in HFDPC/SPFO due to better chain packing in the fully fluorinated bilayer. However, the vesicle region is expanded in more asymmetric fluorinated bilayers of HFDPC/SPFH (sodium perfluorohexanoate). The increased chain asymmetry in HFDPC/SPFH results in reduced packing density and more fluid bilayers than in HFDPC/SPFO. The robustness of CPB/SPFO and HFDPC/SPFO vesicles is demonstrated in the synthesis of silica hollow spheres by templating and the retention of encapsulated solutes. Higher colloidal stability of the silica spheres is achieved in HFDPC/SPFO relative to CPB/SPFO due to the barrier effect of the fluorinated bilayer. Similarly, higher solute retention in HFDPC/SPFO is observed. The modulation of phase behavior with fluorination offers opportunities in tunable applications of fluorinated bilayers.

The main aim of this work was the study of bacteria capable to degrade the pyridine monocarboxylic acids. Achromobacter sp. strain JS18 capable to utilize 3-hydroxypyridine- 2-carboxylic acid was selected by screening of microorganisms hydroxylating the pyridine ring at unusual positions or transforming pyridine derivatives . The strain 5HP consuming 5- hydroxypyridine-2-carboxylic acid as a sole carbon and energy source was isolated from soil. The 16S rRNA-based phylogenetic analysis showed that the isolate belongs to Pusillimonas genus. It was found that picolinic, nicotinic and dipicolinic acids were metabolized via three distinct inducible pathways in Achromobacer sp. JS18. The appropriate biodegradation routes of these acids as well as 3-hydroxypyridine-2-carboxylic acid were was proposed. Nicotinic acid, 5-hydroxypicolinic acid and 3-hydroxypyridine induced three distinct metabolic pathways in Pusillimonas sp. 5HP cells. All pathways had the same intermediate – 2,5-dihydroxypyridine. For the first time 5-hydroxypicolinate 2-monooxygenase, which catalyzed oxidative decarboxylation of 5-hydroxypicolinic acid, was discovered, partially purified and characterized. The analysis of Sinorhizobium sp. L1 cells showed that 3-hydroxypyridine and nicotinic acid were degraded via different metabolic pathways. The Sinorhizobium sp. L1 cells converted 3-hydroxymethylpyridine to nicotinic acid. 3-hydroxypyridine and nicotinic acid induced biosynthesis of distinct isoforms of 2... [to full text] / Šio darbo metu buvo tiriamos bakterijos, galinčios skaidyti piridino monokarboksirūgštis. Netradicinėse vietose hidroksilinančių ir/ar hidroksilintų pikolino ir nikotino rūgščių skaidyme dalyvaujančių mikroorganizmų atranka leido identifikuoti Achromobacter sp. JS18 bakteriją, skaidančią 3-hidroksipiridino-2-karboksirūgštį, ir iš dirvožemio išskirti 5HP kamieną, galintį panaudoti 5-hidroksipiridino-2-karboksirūgštį vieninteliu anglies ir energijos šaltiniu. 16S rRNR geno analizės duomenimis 5HP kamienas priklauso Pusillimonas genčiai. Tai pirmoji žinoma bakterija, galinti skaidyti 5- hidroksipiridino-2-karboksirūgštį. Nustatyta, kad Achromobacter sp. JS18 bakterijose yra indukuojami trys skirtingi piridino monokarboksirūgščių skaidymo keliai. Pasiūlyti pikolino, nikotino, dipikolino rūgščių ir 3-hidroksipiridino-2-karboksirūgšties, skaidymo keliai. Pusillimonas sp. 5HP ląstelėse pirmą kartą aptikta ir dalinai išgryninta 5- hidroksipikolinato 2-monooksigenazė, katalizuojanti 5-hidroksipiridino-2-karboksirūgšties oksidacinį dekarboksilinimą, susidarant 2,5-dihidroksipiridinui. 5HP bakterijose yra indukuojami trys (3-hidroksipiridino, 5-hidroksipikolino ir nikotino rūgščių) skaidymo keliai, susidarant bendram metabolitui – 2,5-dihidroksipiridinui. Tiriant Sinorhizobium sp. L1 ląstel÷s, buvo nustatyta, kad 3-hidroksipiridino ir nikotino rūgšties skaidymas vyksta skirtingais keliais. 3-Hidroksimetilpiridinas L1 ląstelėse yra oksiduojamas iki nikotino rūgties ir skaidymas vyksta... [toliau žr. visą tekstą]

Šio darbo metu buvo tiriamos bakterijos, galinčios skaidyti piridino monokarboksirūgštis. Netradicinėse vietose hidroksilinančių ir/ar hidroksilintų pikolino ir nikotino rūgščių skaidyme dalyvaujančių mikroorganizmų atranka leido identifikuoti Achromobacter sp. JS18 bakteriją, skaidančią 3-hidroksipiridino-2-karboksirūgštį, ir iš dirvožemio išskirti 5HP kamieną, galintį panaudoti 5-hidroksipiridino-2-karboksirūgštį vieninteliu anglies ir energijos šaltiniu. 16S rRNR geno analizės duomenimis 5HP kamienas priklauso Pusillimonas genčiai. Tai pirmoji žinoma bakterija, galinti skaidyti 5- hidroksipiridino-2-karboksirūgštį. Nustatyta, kad Achromobacter sp. JS18 bakterijose yra indukuojami trys skirtingi piridino monokarboksirūgščių skaidymo keliai. Pasiūlyti pikolino, nikotino, dipikolino rūgščių ir 3-hidroksipiridino-2-karboksirūgšties, skaidymo keliai. Pusillimonas sp. 5HP ląstelėse pirmą kartą aptikta ir dalinai išgryninta 5- hidroksipikolinato 2-monooksigenazė, katalizuojanti 5-hidroksipiridino-2-karboksirūgšties oksidacinį dekarboksilinimą, susidarant 2,5-dihidroksipiridinui. 5HP bakterijose yra indukuojami trys (3-hidroksipiridino, 5-hidroksipikolino ir nikotino rūgščių) skaidymo keliai, susidarant bendram metabolitui – 2,5-dihidroksipiridinui. Tiriant Sinorhizobium sp. L1 ląstel÷s, buvo nustatyta, kad 3-hidroksipiridino ir nikotino rūgšties skaidymas vyksta skirtingais keliais. 3-Hidroksimetilpiridinas L1 ląstelėse yra oksiduojamas iki nikotino rūgties ir skaidymas vyksta... [toliau žr. visą tekstą] / The main aim of this work was the study of bacteria capable to degrade the pyridine monocarboxylic acids. Achromobacter sp. strain JS18 capable to utilize 3-hydroxypyridine- 2-carboxylic acid was selected by screening of microorganisms hydroxylating the pyridine ring at unusual positions or transforming pyridine derivatives . The strain 5HP consuming 5- hydroxypyridine-2-carboxylic acid as a sole carbon and energy source was isolated from soil. The 16S rRNA-based phylogenetic analysis showed that the isolate belongs to Pusillimonas genus. It was found that picolinic, nicotinic and dipicolinic acids were metabolized via three distinct inducible pathways in Achromobacer sp. JS18. The appropriate biodegradation routes of these acids as well as 3-hydroxypyridine-2-carboxylic acid were was proposed. Nicotinic acid, 5-hydroxypicolinic acid and 3-hydroxypyridine induced three distinct metabolic pathways in Pusillimonas sp. 5HP cells. All pathways had the same intermediate – 2,5-dihydroxypyridine. For the first time 5-hydroxypicolinate 2-monooxygenase, which catalyzed oxidative decarboxylation of 5-hydroxypicolinic acid, was discovered, partially purified and characterized. The analysis of Sinorhizobium sp. L1 cells showed that 3-hydroxypyridine and nicotinic acid were degraded via different metabolic pathways. The Sinorhizobium sp. L1 cells converted 3-hydroxymethylpyridine to nicotinic acid. 3-hydroxypyridine and nicotinic acid induced biosynthesis of distinct isoforms of 2... [to full text]

Les neurotoxiques organophosphorés (NOP) sont extrêmement toxiques et peu volatils. Dans des conditions normales de température et de pression, ils peuvent pénétrer rapidement la peau sous forme liquide et exercer leurs effets délétères. En milieu civil ou militaire, leur utilisation potentielle est toujours redoutée. Le développement de dispositifs de protection cutanée vis-à-vis de ces agents est donc d’un intérêt majeur pour les armées et la sécurité civile. Dans ce contexte, les objectifs de ce travail ont été de formuler et évaluer la stabilité et l’efficacité de topiques protecteurs cutanés (TP) vis-à-vis des NOP. Le premier objectif a consisté à mettre au point des TP de compositions et de formes galéniques différentes (émulsions, gels) puis à valider leurs stabilités physicochimiques. Cent trente TP ont été formulés et 30 ont montré une stabilité physicochimique satisfaisante. Le second objectif a été d’évaluer l’efficacité des TP les plus prometteurs vis-à-vis des composés organophosphorés. Actuellement il n’existe pas de standardisation de ce type d’étude. Par conséquent, l’utilisation de plusieurs tests in vitro et in vivo (membranes biologiques ou synthétiques, NOP ou simili), dont la pertinence et la fiabilité ont été déterminées, nous a permis d’établir une logique de criblage pour l’évaluation de l’efficacité des TP. Parmi les 13 formulations testées, les résultats ont montré qu’un gel hydro-alcoolique apporte une protection cutanée significative et supérieure aux produits de référence testés vis-à-vis du VX, un NOP d’intérêt / Prevention of exposure to the neurotoxic organophosphorus compounds (OP) that are quickly absorbed in the skin is a major concern both for pesticide users and soldiers. Skin barrier creams are being developed to complement or replace uncomfortable chemical protective suits. The objectives of this work were to formulate and assess physicochemical stability and protective efficacy of topical skin protectant (TSP) against OP compounds. The first objective was to formulate several different TSP (emulsions, gel) and validate their physicochemical stability.The second objective was to determine the consistency of results from in vitro tests and the importance of the formulation composition in the skin protective efficacy. Quick evaluation of formulations efficacy mainly relies on in vitro tests which lead to consistent, complementary and relevant results. Our results indicated that the least effective formulations could be quickly identified by performing in vitro permeation tests with silicone membrane and by evaluating interfacial interactions between formulations and OP. We showed that a hydrogel containing specific hydrophilic polymers was by far the most effective of the formulations evaluated against VX, OP compounds, skin permeation in vitro