Les espèces réactives de l’oxygène (ERO) contrôlent plusieurs aspects de la carcinogenèse, étant donné leur capacité àpromouvoir la prolifération mais aussi à induire la sénescence et l’apoptose. Dans les stades avancés de cancer, les EROpeuvent également participer au développement de l’atrophie musculaire, engendrant une détérioration de la qualité de viedes patients. L’activité physique (AP), connue pour augmenter les défenses antioxydants de l’organisme et lasupplémentation en antioxydants sont considérées comme deux stratégies susceptibles de moduler la croissance tumorale, d’améliorer la performance physique et de réduire les effets secondaires liés à la maladie et aux traitements anticancéreux. Néanmoins, plusieurs questions restent aujourd’hui sans réponse. En effet, bien que l’AP puisse réduire la progression du cancer du sein, du colon et de la prostate, son impact sur les cancers se développant au sein du muscle (ex : le liposarcome), donc soumis aux contractions musculaires répétées, reste méconnu. En utilisant des approches in vivo et in vitro, nous avons démontré que maintenir une AP régulière accélère la croissance du liposarcome intramusculaire, probablement, via la réduction des taux circulants d’insuline et l’inhibition de la voie « P38 MAPK-P21 ». Pour les patients ne pouvant pas pratiquer d’AP, la consommation d’antioxydants pourrait être un moyen de réduire les ERO tumorales et musculaires et ainsi être prometteuse. Toutefois, les études actuelles restent très controversées. Nos travaux ont montré dans un modèle murin de cachexie cancéreuse que des doses nutritionnelles d’un produit antioxydant commercialisé en France, étaient suffisantes pour accélérer la croissance de la tumeur colique, favoriser la perte de masse corporelle totale et musculaire et engendrer la mort prématurée des souris. L’ensemble de nos résultats suggère que la pratique d’AP et la consommation en antioxydants peuvent induire des effets différents selon le type de tumeur et leur implantation, nécessitant une prise en charge individualisée des patients. En effet, (1) les patients atteints d’un LS intramusculaire devraient éviter de pratiquer une AP durant la période préopératoire mais ces résultats doivent être confirmés par une étude clinique, (2) les patients avec un stade avancé de cancer devraient être vigilants quant à l’utilisation de suppléments antioxydants ; une telle pratique pouvant avoir des répercussions dangereuses sur leur santé. / Reactive oxygen species (ROS) control several aspects of carcinogenesis as they can either promote tumor growth andprogression or senescence and apoptosis. In advanced stages of cancer, ROS can also drive the development of other cancerrelated complications like, muscle wasting. Physical activity (PA) and antioxidant supplementation have been proposed as two adjuvant strategies to better control tumor growth, ameliorate performance and alleviate secondary symptoms related to cancer itself or to the heavy anticancer therapies. However, several issues remain to be elucidated. First of all, although PA could reduce colon, breast and prostate cancer growth and progression, its impact remains unknown on orthotopic intramuscular tumors like liposarcoma, which directly affect the musculoskeletal apparatus and reduce physical function. Secondly, given the limitedness of PA application in some advanced stages of cancer, patients may increase their dependency on nutritional and antioxidant complements as an alternative strategy, but such practice has spark a lot of polemic and inconsistent results. In this thesis, we have addressed the effectiveness of PA and antioxidants in two distinct animal models of cancer. Using in vivo and in vitro approaches, we found that voluntary PA accelerated the growth of intramuscular liposarcoma tumors and exacerbated skeletal muscle dysfunction, mainly, by decreasing circulating insulin levels and the subsequent activation of the tumor suppressor pathway “P38 MAPK-P21”. We also demonstrated that nutritional doses of commercial antioxidants enhanced colon tumor growth, total body/skeletal muscle weight loss and caused premature death of mice. Such mechanism was due to selective changes in oxidative damage profiles, which decreased in tumor but increased in skeletal muscle, in a way driving tumor growth and skeletal muscle wasting/dysfunction. Clinically, it seems that (1) patients with intramuscular liposarcoma may, at least, not increase their levels of PA or undergo hospital-supervised exercise program, during the preoperative period; until the confirmation of our findings with clinical data and (2) patients with advanced stages of cancer must be very careful against the use of antioxidants as it could lifethreatening. Accordingly, health agencies in France, Europe and USA prohibit the use of synthetic antioxidant supplements without dietary counseling by a cancer patient’s physician and/or nutritionist.

Le stress oxydant se définit comme un déséquilibre entre la production d’espèces oxygénées et azotés réactives et les défenses antioxydants. Ce phénomène est associé à de nombreuses pathologies telles que des maladies neurodégénératives et cardiovasculaires ou des cancers. Pour contrecarrer les dégâts causés par le stress oxydant, l’utilisation d’antioxydants synthétiques s’est avérée intéressante car il devient alors possible de modifier les propriétés physico-chimiques des antioxydants et de leur assurer un meilleur ciblage cellulaire et tissulaire. Nos travaux de recherche se positionnent dans la recherche de nouveaux agents antioxydants synthétiques. Au cours de cette thèse nous nous sommes focalisés sur l’utilisation de l’alpha-phényl-N-tert-butylnitrone (PBN), qui présente une bonne activité pharmacologique contre les dégâts liés aux radicaux libres, et qui est également largement utilisée en tant que sonde analytique pour l’identification d’espèces radicalaires par la technique de piégeage de spin couplée à la résonance paramagnétique électronique (RPE). Dans la première partie de ces travaux de thèse, nous avons tenté d’améliorer les propriétés intrinsèques de la PBN en greffant divers substituants soit sur le cycle aromatique, soit sur le groupement N-tert-butyl de la fonction nitrone. L’analyse des propriétés physico-chimiques et biologiques de ces composés nous a permis de mesurer l’impact de la nature et de la position des substituants sur les propriétés antioxydantes de la PBN. La seconde partie de ces travaux a consisté à greffer le motif PBN sur des structures moléculaires amphiphiles dérivées d’un acide-aminé. Cette deuxième partie a pour but d’améliorer l’activité biologique et la biodisponibilité des dérivés PBN. / Oxidative stress is defined as an unbalance between the production of free radicals and the antioxidant defenses. The oxidative stress state has been associated with several pathologies such as neurodegenerative and cardiovascular diseases or cancers. To prevent oxidative stress-mediated damage, the use of synthetic antioxidants is attractive as it allows to tune their physico-chemical properties as well as their cellular targeting specificity. Of particular interest is the linear alpha-phenyl-N-tert-butylnitrone (PBN) which exhibits pharmacological activity against radical-mediated pathophysiological conditions and has been widely used as analytical reagent for the identification of radical species by the spin-trapping method coupled to electron paramagnetic resonance (EPR) spectroscopy. In this thesis report, we first tried to improve the intrinsic antioxidant properties of PBN by grafting various substituents either onto the aromatic ring or the N-tert-butyl-group of the nitronyl function. The physico-chemical and biological properties of the compounds were then determined. With optimized nitrone derivatives in hand, the second part of this project consisted in improving the bioactivity and bioavailability of our nitrone agents using amphiphilic carriers or specific targeting ligands.

>Magister Scientiae - MSc / Cissampelos capensis, is commonly known by the Afrikaans name ‟dawidjies” or ‟dawidjieswortel”. C. capensis is the most important and best known medicinal plant of the family Menispermaceae used by the Khoisan and other rural people in the western regions of South Africa. Among numerous other ailments, it is traditionally taken to treat male fertility problems. Yet, no studies have investigated the effects of this plant or its extracts on human spermatozoa. The aim of study was to investigate the effects of C. capensis rhizome extracts on sperm function.

Free radicals have been implicated in the progression of various diseases, such as cancers and cardiomyopathies. When the body is overburdened with free radicals and endogenous antioxidants become depleted, oxidative stress ensues with resultant damage to biomolecules. During oxidative stress high levels of reactive oxygen species are generated, cellular viability decreases, and apoptosis and lipid peroxidation are induced. Supplementation with exogenous supplements rich in antioxidants, such as herbal remedies containing polyphenols, could result in increased protection against oxidative stress. The aim of the study was to assess the effect of Burkea africana and Syzygium cordatum in a cellular oxidative stress model for the potential development of an antioxidant supplement. Crude aqueous and methanolic extracts were prepared by solvent maceration, while a polyphenolic-rich extract was created through liquid-liquid extraction. Polyphenolic content and antioxidant activity was assessed in cell-free systems. Polyphenolic content was determined through the Folin-Ciocalteau and aluminium trichloride methods, while antioxidant activity was assessed by the Trolox Equivalence Antioxidant Capacity and 1,1-diphenyl-2-picrylhydrazyl radical assays. Identification of phytochemical classes was done through thin layer chromatography and biochemical reactions. Inherent cytotoxicity of samples was determined in four cell cultures (3T3-L1 pre-adipocytes, C2C12 myoblasts, normal human dermal fibroblasts and U937 macrophage-like cells) using the neutral red uptake assay. The effect on oxidative stress was assessed in 2,2`-azobis-(2-methylpropionamidine) dihydrochloride-exposed U937 macrophage-like cells with regards to reactive oxygen species generation, cytotoxicity, apoptosis, lipid peroxidation and GSH depletion. Both B. africana and S. cordatum showed enrichment of polyphenols from the aqueous extract, to methanolic extract, to polyphenolic-rich extract. Antioxidant activity showed the same trend, which correlated well with the increased concentration of polyphenols, such as catechin, gallic acid and myricetin. Samples indicated toxicity in the 3T3-L1 and C2C12 cell lines, though no toxicity was noted in the U937 cell line and normal human dermal fibroblast cultures. Free radical-induced generation of reactive oxygen species, cytotoxicity, lipid peroxidation and apoptosis was successfully reduced by crude extracts of B. africana and the polyphenolic-rich extracts of both plants between concentrations of 10 and 20 ìg/ml. The crude extracts of S. cordatum were mostly ineffective in reducing these parameters, even though cell viability was increased. B. africana pre-treatment decreased reduced glutathione concentrations significantly in a dose-dependent manner, while the methanolic and polyphenolic-rich extract of S. cordatum increased concentrations moderately. Polyphenolic-rich extracts of B. africana and S. cordatum had the most potent decrease in oxidative stress-related parameters in the present study, which could be attributed to the polyphenolic content and antioxidant activity. Limited cytotoxicity was apparent in two of the four cell lines tested; further isolation and purification needs to be carried out to assess the bioactive constituents which do not elicit a toxic response. Further investigation through the use of quantitative structure–activity relationship modeling could give more insight on conformational and chemical changes that need to be brought about to modify the bioactive phytochemicals for reduced cytotoxicity, but increased antioxidant activity. Copyright / Dissertation (MSc)--University of Pretoria, 2013. / Pharmacology / unrestricted

Orientadores: Mary Anne Heidi Dolder, Fernanda Ramos Gadelha, Mary Anne Heidi Dolder / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T11:14:48Z (GMT). No. of bitstreams: 1 Leite_RodrigoPaula_D.pdf: 2410216 bytes, checksum: 7bc6c22d763f8f597e6e6208e8d60e5f (MD5) Previous issue date: 2015 / Resumo: Heteropterys tomentosa A. Juss. é uma planta endêmica do cerrado brasileiro cuja raiz é popularmente utilizada como planta medicinal. O extrato vegetal é consumido de maneira rudimentar e sem qualquer forma de extração padronizada. No entanto, determinadas propriedades com potencial clínico são descritas na literatura para o extrato de H. tomentosa. Entre estas, expressiva atividade antioxidante in vivo, a qual poderia ser contribuir para os efeitos benéficos à saúde do composto. Portanto, propôs-se investigar neste trabalho os mecanismos antioxidantes do extrato de H. tomentosa em testículo de ratos Wistar submetidos a estresse oxidativo por cloreto de cádmio. Dois possíveis mecanismos bioquímicos foram considerados: capacidade de quelar íons de cádmio e de metais de transição, como ferro e cobre; capacidade de neutralizar espécies reativas de oxigênio. Os animais foram organizados em quatro grupos (n=5) e tradados durante 30 dias: Controle - ingestão ad libitum de água; Cd - ingestão ad libitum de solução aquosa de cloreto de cádmio [75mg/L]; Ht - uma injeção intraperitoneal diária do extrato vegetal NSE50 [50 mg/Kg Pc]; CdHt - ingestão ad libitum de solução aquosa de cloreto de cádmio [75mg/L] concomitantemente à injeção intraperitoneal diária do extrato vegetal NSE50 [50 mg/Kg Pc]. Ao término do tratamento, as amostras de testículo foram coletadas e submetidas a análises bioquímicas, estereológicas e histopatológicas. Os resultados demonstram que o extrato de H. tomentosa reduziu significativamente as taxas de peroxidação lipídica nos animais submetidos ao cádmio. As evidências sugerem que ambos os mecanismos antioxidantes inicialmente propostos estão envolvidos neste processo. Isto é, o extrato possui propriedades quelantes associadas à capacidade de neutralizar as EROs normalmente formadas após a exposição ao metal. Adicionalmente, os resultados acusam a presença de cádmio no testículo dos animais não expostos experimentalmente, provavelmente obtido através da ração comercial. Este cenário expõe um grave problema ambiental envolvendo a presença do metal na agricultura voltada para o consumo humano e, dessa forma, reforça os estudos populacionais que correlacionam exposição não ocupacional ao cádmio com diversas patologias idiopáticas / Abstract: Heteropterys tomentosa A. Juss. is an endemic Brazilian bush whose root is widely used as a medicinal plant. The plant extract is traditionally taken imbibed in alcohol and, therefore neither go through any standard extraction procedure nor has its active compounds identified. Nonetheless, the literature have reported some pharmacological properties with clinical potential for H. tomentosa root extract, such as a relevant in vivo antioxidant activity. Therefore, its health benefits could partially be attributed to the capacity of reducing the oxidative stress in the organism. For this reason, the aim of the present study is to shed light on the antioxidant mechanisms of H. tomentosa in Wistar rat testis undergoing cadmium induced lipid peroxidation. Two possible mechanisms have been investigated: the capacity of chelating cadmium and transitional metal ions, such as iron and copper; the capacity of ROS scavenging. Animal were set into four different groups (n=5) and submitted to different treatments for 30 days: Control - water ad libitum; Cd - water plus cadmium solution [75mg/L] ad libitum; Ht - daily intraperitoneal injection of NSE50 extract [50 mg/Kg Pc]; CdHt - water plus cadmium solution [75mg/L] ad libitum accompanied by a daily intraperitoneal injection of NSE50 extract [50 mg/Kg Pc]. At the end of the treatment, testis samples were collected and submitted to stereological, histopathological and biochemical analyses. The results showed a significant reduction in lipid peroxidation rates for the animals submitted to cadmium diet and simultaneously treated with the NSE50 extract. Our data indicates that two antioxidants mechanisms are employed by the plant extract: a cadmium chelating property and a ROS scavenging activity. In addition, results show the presence of cadmium in testis of control and Ht group, although they were not experimentally exposed to the metal. These animals are likely to have been contaminated through rat ration, mainly made from corn. This scenario exposes a current environmental issue involving agriculture for human consumption and, thus reinforces some epidemilogical studies correlating cadmium and several idiopathic pathologies / Doutorado / Biologia Celular / Doutor em Biologia Celular e Estrutural

A produção de espécies reativas de oxigênio (ROS) nos sistemas biológicos é contrabalanceada pelos sistemas antioxidantes enzimáticos e não-enzimáticos. Quando há um desequilíbrio entre a geração de ROS e esses sistemas, ocorre um aumento dessas espécies reativas causando estresse oxidativo, que pode levar a danos a macromoléculas, como lipídios, proteínas e o DNA. Os fármacos doxorrubicina (antineoplásico) e benzonidazol (antiparasitário) são conhecidos por induzir efeitos colaterais que podem estar relacionados ao aumento de ROS. Além disso, ensaios de mutagenicidade demonstram que esses fármacos apresentam atividade mutagênica por danos oxidativos. O Grupo NEQUIMED desenvolve substâncias com potencial atividade antineoplásica e antiparasitária, as quais ainda não foram avaliadas em relação às propriedades tóxicas e genotóxicas. Dessa forma, o objetivo deste trabalho foi analisar as propriedades mutagênicas e de estresse oxidativo dessas novas substâncias, comparando aos fármacos benzonidazol e doxorrubicina. Para detecção de ROS foi realizado o ensaio fluorimétrico utilizando o marcador 2,7-diacetato de diclorofluoresceína (DCFH-DA) em linhagens celulares de hepatocarcinoma humano (HepG2) e fibroblasto de camundongo (Balb/C 3T3 clone A31). O estado redox destas células foi avaliado através da quantificação da expressão gênica e do conteúdo proteico das enzimas antioxidantes através das técnicas de qRT-PCR e Western blot, respectivamente. A atividade mutagênica foi analisada com o ensaio Ames miniaturizado Salmonella/microssoma utilizando a linhagem TA102 de Salmonella typhimurium que detecta agentes mutagênicos que causam danos por oxidação. Os resultados mostraram que as substâncias estudadas pelo Grupo não induzem aumento na produção de ROS ou induzem em menores níveis do que doxorrubicina e benzonidazol, além de levar a alterações menos proeminentes que os fármacos para a expressão das proteínas antioxidantes. No ensaio mutagênico, o benzonidazol apresentou o pior perfil, doxorrubicina e Neq0438 somente foram mutagênicos com ativação enzimática, enquanto Neq0551 foi inativo. Assim, as novas substâncias (Neq0438 e Neq0551) apresentaram um perfil melhor do que os fármacos de referência, tornando-os candidatos promissores para estudos in vitro e in vivo subsequentes. / The production of reactive oxygen species (ROS) in biological systems is compensated by the enzymatic and non-enzymatic antioxidant systems. The excessive ROS production causes oxidative stress, which can damage important cellular macromolecules such as lipids, proteins and DNA. The drugs doxorubicin (antineoplastic) and benzonidazole (antiparasitic) are both known for their side effects, which can be related to the increase of ROS. Besides, mutagenicity assays show that these drugs have a mutagenic activity via oxidative damages. The research group NEQUIMED studies new substances with potential antineoplastic and antiparasitic activities, but their toxic and genotoxic properties have not been fully evaluated yet. Thus, the aim of this work is to assess the mutagenic potential and the oxidative stress generated by these substances, comparing them to benzonidazole and doxorubicin. The fluorimetric assay using the probe dichloro-dihydro-fluorescein diacetate (DCFH-DA) was used for ROS detection in human hepatocarcinoma (HepG2) and mouse fibroblast (Balb/C 3T3 clone A31) cell lines. The redox state of these cells was evaluate by qRT-PCR and Western blot methods to quantifying gene expression and protein content of the antioxidant enzymes. The mutagenic potential was assessed by the miniaturized Ames text with the Salmonella/microssome mutagenicity assay, using the TA102 strain of Salmonella typhimurium, which detects oxidation damages to the DNA. The new substances did not induce an increase on ROS production, or did in lower levels when compared to doxorubicin and benzonidazole. Moreover, reference drugs also induced greater changes on the expression of the antioxidant enzymes. Benznidazole had a higher mutagenic activity, while Neq0438 and doxorubicin were mutagenic only when incubated with enzymatic activation. Neq0551 was inactive for Ames assay. Therefore, these new substances (Neq0438 and Neq0551) had a better overall profile than the reference drugs, turning out to be promising candidates for further in vitro and in vivo studies.

A Araucaria angustifólia é uma conífera nativa do Brasil que apresenta sementes recalcitrantes. Devido a sua importância econômica, foi intensamente explorada ao longo dos anos, encontrando-se atualmente classificada como espécie em perigo crítico de extinção pela International Union for Conservation of Nature. A embriogênese somática apresenta-se como uma ferramenta biotecnológica de grande valia na propagação de espécies recalcitrantes e de difícil propagação, com aplicação em programas de conservação, reflorestamento, e melhoramento genético vegetal. Estudos comparativos dos processos de embriogênese somática e zigótica têm permitido o conhecimento dos fatores bioquímicos, fisiológicos e genéticos que controlam o desenvolvimento do embrião, e o estabelecimento as condições artificiais para o correto desenvolvimento embrionário in vitro. O objetivo deste trabalho foi estudar a participação do ácido salicílico como sinalizador do processo de embriogênese zigótica e somática em A. angustifólia. Para tanto foi determinado o conteúdo de ácido salicílico livre e conjugado ao longo da embriogênese zigótica, e o efeito de sua suplementação em culturas embriogênicas com diferentes potenciais para a maturação. Para a embriogênese somática, a presença do ácido salicílico foi correlacionada com a geração de óxido nítrico e espécies reativas de oxigênio , e com a expressão do gene \"Somatic Embryogenesis Receptor Kinase\" (AaSERK). Os resultados obtidos demonstram que: a) ocorre um maior conteúdo de ácido salicílico na forma livre e conjugada nas etapas iniciais da embriogênese zigótica; b) a suplementação de ácido salicílico, nas concentrações de 0,5 a 2 mM, inibiram a indução de culturas embriogênicas; c) culturas embriogênicas incubadas em ácido salicílico apresentaram redução da síntese endógena de espécies reativas de oxigênio e aumento no conteúdo de óxido nítrico; d) a redução de espécies reativas de oxigênio indicou uma relação dose dependente com o ácido salicílico; e) a adição de um doador de óxido nítrico e um sequestrador inibiram a produção de espécies reativas de oxigênio; f) a expressão do gene AaSERK atingiu o maior nível no período de quatro horas de incubação em 0,1 mM de AS / Araucaria angustifolia is a conifer native of Brazil with recalcitrant seeds. Due to its economic importance, the exploration has been extensively over the years, currently this specie is classified as critically endangered by the International Union for Conservation of Nature. Somatic embryogenesis is presented as a biotechnological tool of great value in the propagation of recalcitrant species and difficult to spread, with applications in conservation, reforestation programs, and plant breeding. Comparative studies of the processes of zygotic and somatic embryogenesis has allowed the knowledge of biochemical, physiological and genetic factors that control embryo development, and the establishment artificial conditions for proper embryonic development in vitro. The objective of this work was to study the role of salicylic acid as a marker of zygotic embryogenesis and somatic process in A. angustifolia. Thus, we determined the content of free salicylic acid and conjugated along the zygotic embryogenesis, and the effect of their supplementation with different potential embryogenic cultures for maturation. For somatic embryogenesis, the presence of salicylic acid was correlated with the generation of nitric oxide, reactive oxygen species and in the gene expression \"Somatic embryogenesis Receptor Kinase\" (AaSERK). The results show that: a) there is an increased content of salicylic acid in free and conjugated form in the initial stages of zygotic embryogenesis; b) salicylic acid supplementation, in concentrations from 0.5 to 2 mM, inhibited the induction of embryogenic cultures; c) embryos incubated in salicylic acid decreased endogenous synthesis of reactive oxygen species and increase in content of nitric oxide; d) the reduction of reactive oxygen species indicated a dose-dependent relationship with salicylic acid; e) the addition of a nitric oxide donor and a kidnapper inhibited the production of reactive oxygen species; f) the expression of the gene AaSERK reached the highest level in four hours of incubation in 0.1 mM AS

The phagocytic cells circulating in the bloodstream play a key role in both the defense of the body and the pathology of inflammatory diseases. Thus, targeting their functions has potential to modulate an immune response, especially during the inflammatory phase. This master's thesis was focused on the influence of electric pulses on the most abundant phagocyte population in human peripheral blood, namely neutrophils. The theoretical part describes the role of neutrophils in the development of the immune response and the effects of the electric field on various cells. Consequent part of the thesis was the optimization of the electrical stimulation of neutrophils using a unique platform with a network of gold electrodes. In stimulated cells by electrical pulses, activation of selected signaling pathways, degranulation, ROS production, citrullination of histone H3 and expression of surface markers were monitored. Overall, electrical stimulation was observed to induce neutrophil activation but only electrical pulses of size 1 V were found to be statistically significant in the case of ROS production and 10 mV and 100 mV electrical pulses in the case of metalloproteinase MMP8 degranulation. The absence of significant effects in the most observed parameters was probably due to unwanted activation of neutrophils in control samples.

Non-thermal plasma has a lot of ways for using in nowadays medicine. It presents many useful actions like charged particles, UV light, electric field, radicals, excited atoms and molecules. That complicated chemistry directs to uncountable synergistic interaction between cold plasma and biological systems, involve cells and tissues. This thesis is about effects of cold plasma to wound healing. Two different microwave plasma systems were used for the presented study. The first one was argon plasma torch generated by surface wave using the quartz capillary, the second one was plasma torch with reverse vortex argon flow. Diagnostics of plasma jet by optical emission spectroscopy shown the presence of active particles, which are responsible for a lot of impact of plasma treatment. Concentrations of active particles generated by plasma are dependent on conditions of plasma generation like power of generator and gas flow. For visual evidence of effects on skin caused by active particles was created simulation of skin tissue. Interaction between plasma jet and artificial skin tissue shown that UV light and temperature are not responsible for all observed effects which are noticed after plasma treatment. Some part of experiments was realized in collaboration with Medical University of Sofia in Bulgaria. The theory of positive effect to wound healing was supported by experiments based on treating artificially created wounds on laboratory mice by cold plasma. It was proved, that process of wound healing is significantly shorter after using plasma treatment in comparison with normal wound healing. Plasma treating of wound for 10 seconds in two consequent days seems like more effectively than application of plasma only one day. This Thesis was carried out as a part of international project PLASMABORDER that was supported by European commission under cohesion funds; programme INTEREG SK-CZ under contract No. 304011P709.

Saccharothrix algeriensis est une Actinobactérie rare capable de synthétiser divers dérivés de dithiolopyrrolones (DTPs) aux propriétés phytosanitaires intéressantes. L'objectif de la thèse vise à développer différentes méthodes, alternatives à la synthèse organique, pour optimiser la production de DTPs par la régulation du métabolisme de la bactérie. Deux approches ont été envisagées : * la première fait appel à des éliciteurs chimiques tels que l'éthanol, le butan-1-ol, le diméthylsulfoxyde et des homosérines lactones (C4-HSL, 3-oxo-C12-HSL et 3-OH-C12-HSL). Les effets de la concentration de ces composés et du temps d'addition dans le milieu de culture ont été étudiés et une investigation sur le mécanisme d'action de l'éthanol a été initiée * la deuxième utilise une approche physico-chimique innovante modifiant le métabolisme microbien à l'aide d'une électrode polarisée. Des électrodes en carbone, en acier et en platine de topographies variées ont servi pour l'étude de l'effet du potentiel, par rapport à une électrode au calomel saturée (ECS), sur la croissance de S. algeriensis et la production de dithiolopyrrolones. Les résultats obtenus montrent que l'ajout de l'éthanol à une concentration de 1,74 % v/v ou du diméthysulfoxyde à 3 % v/v au début de la culture, induit une augmentation significative de la production spécifique des DTPs. Celle-ci est multipliée par un facteur 19 avec l'éthanol et par 6 avec le diméthylsulfoxyde. Dans le cas de l'éthanol, cette induction serait médiée par des espèces réactives de l'oxygène. Par ailleurs, l'ajout simultané de la C4-HSL et de la 3-oxo-C12-HSL à des doses successives de 500 µM permet de multiplier la production spécifique des DTPs par un facteur 2,5. L'utilisation d'une électrode polarisée, en platine ou en carbone, permet un bon développement mycélien de S. algeriensis contrairement à une électrode en acier. Sous le potentiel -0.3 V/ECS, des concentrations élevées en dithiolopyrrolones ont été quantifiées. / Saccharothrix algeriensis is a rare Actinobacterium that produces a variety of dithiolopyrrolone derivatives (DTPs). These biocidal compounds are used as plant and crop- protection products. The aim of this thesis is to develop new strategies for DTPs production by regulating bacterial metabolism as an alternative to the chemical synthesis of these compounds. Two strategies were used : * the first strategy consist of using chemical elicitors such as ethanol, butan-1-ol, dimethylsulfoxide and homoserine lactones (C4-HSL, 3-oxo-C12-HSL and 3-OH-C12-HSL). The effects of concentration and time addition of these compounds were studied and ethanol mode of action was investigated. * the second strategy is a physico-chemical innovative approach that modifies bacterial metabolism using a polarized electrod. Platinum, carbon and stainless steel electrodes with varied topographies were used to study the effect of the potential, versus a saturated calomel electrode (SCE), on the growth of S. algeriensis and DTPs production. Our results show that the addition of pure ethanol and dimethylsulfoxide, at the beginning of the culture (t0), in respective concentrations of 1,74 % v/v and 3 % v/v increases DTPs specific production. This one was multiplied by nineteen-fold in presence of ethanol and by six-fold in presence of dimethylsulfoxide. In the case of ethanol, the induction of DTPs biosynthesis is mediated by reactive oxygen species (ROS). Furthermore, simultaneous addition of C4-HSL and 3-oxo-C12-HSL in multiple doses of 500 µM increases DTPs specific production by 2,5 fold. In presence of polarized platinum and carbon electrodes mycelium development of S. algeriensis is thicker than that grown on stainless steel electrode. Although, under - 0,3 V/SCE, high DTPs concentrations were quantified in comparison to other conditions tested.