Os corantes azo são amplamente utilizados em muitas indústrias, entre elas as alimentícias, farmacêuticas e têxteis. Quando essas moléculas estão presentes no efluente industrial tornam o seu tratamento, que na maioria dos casos é biológico, difícil. Suas complexas estruturas são altamente estáveis e a presença de grupos sulfônicos (-SO3H) torna o corante ácido e altamente solúvel em água. Um exemplo deste tipo de corante é a tartrazina que pode causar efeitos adversos para a saúde humana, como alergia. Desde o início dos anos 70, quando os Processos Oxidativos Avançados (POAs) foram reconhecidos por sua capacidade de degradar poluentes em meio aquoso, houve um aumento significativo nas pesquisas por duas razões: a diversidade de tecnologias envolvidas e a grande variedade de efluentes que os POAs são capazes de tratar. A fotoquímica assistida por microondas (MO) consiste na combinação de dois tipos distintos de radiação eletromagnética, microondas e UV/VIS, na ativação de reações químicas. Frequentemente está associada ao uso de uma lâmpada de descarga sem eletrodo (LDE) que gera radiação ultravioleta (UV) sob a influência de um campo de microondas. O presente trabalho tem como objetivo tratar uma solução de tartrazina (25 mg L-1) utilizando o processo H2O2/UV/MO e otimizando-o a fim de se obter a maior degradação com a utilização da menor quantidade de oxidante possível. Para tanto, elaborou-se um planejamento fatorial com a finalidade de observar o comportamento das variáveis independentes pH e concentração inicial de peróxido de hidrogênio no processo. A partir dos resultados, elaborou-se um planejamento composto central a fim de se ajustar um modelo polinomial aos dados obtidos. A condição ótima de tratamento para as variáveis independentes foi: pH = 2,6 e [H2O2] = 2 × 10-3 mol L-1. A variável-resposta observada foi a remoção de cor (por meio da integração da área dos espectros na região do visível). A cinética obtida para o processo H2O2/UV/MO foi de ordem zero, com k = 3,9 × 10-2 u.a.-1 min-1 e, aproximadamente, 92% de descoramento em 24 minutos. A biodegradabilidade (DBO5/DQO) e a análise de carbono orgânico total (COT) não apresentaram variação significativa. No entanto, pôde-se observar, através da CE50, que o processo H2O2/UV/MO reduziu a fitotoxicidade da solução de tartrazina, indicando a possível formação de intermediários de degradação menos tóxicos que a molécula original. A avaliação do efeito das microondas foi feita pelo estudo da degradação da solução de tartrazina através dos processos H2O2, MO, H2O2/MO e UV/MO, sendo que o descoramento não passou de 20%, indicando que as MO influenciam no processo H2O2/UV devido ao possível sinergismo com a radiação UV e também pelos possíveis efeitos térmicos e não térmicos exercidos por essa radiação. / Azo dyes are extensively used in many industries such as food, drugs, and textiles ones. When these molecules are present in the industrial wastewaters, they make their treatment, which is in most cases a biological one, quite difficult. Their complex structures are very stable and the presence of sulfonic groups (-SO3H) makes the azo dyes acid and highly water-soluble. Tartrazine is an example of these dyes and can cause adverse effects to human health, like allergy. Since the early 70\'s, when Advanced Oxidation Processes (AOPs) were recognized by their capacity of degrading pollutants in aqueous media, there was a significant increase in research and for two reasons: the diversity of technologies involved and the many kinds of wastewaters that AOP can treat. The microwave-assisted photochemistry is the combination of two distinct types of electromagnetic radiations: microwave (MW) and UV/VIS. It is often associated with the use of an electrodeless discharge lamp (EDL), which generates ultraviolet (UV) radiation when placed in a microwave field. The aim of the present work is to treat a solution of tartrazine (25 mg L-1) by the H2O2/UV/MW process, as well as optimizing the process in order to obtain degradation with the use of the lowest possible amount of oxidant. For that purpose, a factorial design was performed to observe the effect of the independent variables pH and hydrogen peroxide concentration. With the results obtained, a composite central design was performed to fit a polynomial model to the data. The optimum treatment condition was: pH = 2.6 and [H2O2] = 2 × 10-3 mol L-1. The response variable was color removal (measured by the area under the spectra obtained in the visible region). The decolorization kinetics of the H2O2/UV/MW process followed a zero order model, with k = 3,9 × 10-2 u.a.-1 min-1 and color removal achieved 92% in 24 minutes. The biodegradability (BOD5/COD) ratio and total organic carbon (TOC) analyses showed no significant changes. However, through the CE50 maybe observed that the H2O2/UV/MW process reduced the toxicity of the tartrazine solution, indicating the possible formation of less toxic intermediates than the original molecule. The microwaves effect was assessed in a degradation study of the tartrazine solution by H2O2, MW, H2O2/MW, and UV/MW processes, and the decolorization did not exceed 20%, indicating that the MW influence the H2O2/UV process because of the possible synergism with the UV radiation and thermal and non-thermal effects exerted by the radiation.

Ces dernières années, il est apparu que les espèces réactives de l'oxygène (ROS) ne sont pas seulement des substances délétères qui induisent des dommages de molécules biologiques, mais qu’elles sont également impliquées dans la signalisation cellulaire. Des niveaux contrôlés de H2O2 sont en particulier impliqués dans le processus de régénération chez différentes espèces. Nous avons donc étudié la régulation de la signalisation de H2O2 au cours de régénération de la nageoire caudale chez le poisson zèbre adulte. Nous avons montré que les nerfs contrôlent les niveaux de H2O2 à la fois dans les tissus normaux et après blessure; ce processus est médié par les cellules de Schwann qui expriment Shh. En plus, H2O2 stimule la croissance des nerfs, ce qui suggère la présence d'une boucle de rétrocontrôle positif.Les niveaux redox sont très dynamiques non seulement lors de la régénération, mais aussi au coursdu développement. Nous avons ensuite examiné le rôle de H2O2 pendant la morphogenèse et plusprécisément, son impact sur la croissance axonale et sa relation avec la signalisation Shh. Nous avons constaté que la réduction des niveaux de H2O2, normalement très élevé au cours de la morphogenèse, altère les projections axonales et que cet effet peut être sauvé par l'activation de la voie de signalisation de Shh.Les cibles de la signalisation redox comprennent des protéines dont l'activité est dépendante d'une cystéine, car l'état d'oxydation de cet acide aminé peut être modifié par les niveaux de H2O2. Le processus de S-acylation, qui est très important pour le processus de croissance des projections axonales et pour la voie de signalisation de Shh, consiste en la fixation covalente d'un acide gras, souvent le palmitate, au group sulfurique d’une cysteine et il est donc une cible potentielle de signalisation de ROS. Nous avons mis en évidence une corrélation entre le niveau de palmitoylationd’une protéine et les niveaux de H2O2 dans la cellule. La pertinence de cette observation estactuellement testée in vivo. / In the recent years it is becoming evident that reactive oxygen species (ROS) are not only deleterious compounds that induce damage of biological molecules, but are also important molecules that can mediate different signaling pathways. Controlled ROS, and in particular H2O2, levels have been found to be involved in the regenerative process of different species. We then focused on the regulation of H2O2 signaling during regeneration of the adult zebrafish caudal finand we showed that nerves control H2O2 levels both in normal tissue and after lesioning; this process is mediated by Schwann cells, through Shh signaling. In addition, there is also a reciprocal action of H2O2 on nerve growth, suggesting the presence of a positive feedback loop.Redox levels are highly dynamic not only during regeneration, but also during development. We then looked at the role of H2O2 during morphogenesis and more specifically, its impact on axonal growth and its relationship with Shh signaling. We found that reduction of H2O2 levels, normally very high during morphogenesis, impairs axon projections and that this effect can be rescued by the activation of Shh signaling. Moreover, we found that different redox levels modify the intracellulardistribution of Shh protein and also its extracellular availability. These results further strengthen the relationship between H2O2 and Shh signaling pathways.It is widely accepted that targets of redox signaling include proteins whose activity is dependent on an active cysteine because the oxidative status of this amino acid can be modified by H2O2 levels.The process of S-acylation, which is very important for both the processes of axonal projections growth and Shh signaling, consists in the covalent attachment of a fatty acid, often palmitate, to a cysteine sulphur and it is then a possible target of ROS signaling. We asked whether a relationship between H2O2 levels and protein S-palmitoylation could exist and we found that augmentation of H2O2 levels downregulates the S-palmitoylation process. The relevance of this observation iscurrently being tested in vivo.

Transient receptor potential vanilloid 2 channel (TRPV2) is a Ca2+-permeable ion channel that is highly expressed in leukocytes but is also present in skeletal and cardiac muscle and endocrine cells. The TRPV2 function is implicated in a number of physiological processes, including bacterial phagocytosis, pro-inflammatory cytokine production, cardiac hypertrophy, and cancer development. TRPV2 knockout mice exhibit a high incidence of perinatal mortality, arguing that the channel plays essential roles in physiology. Despite the importance of TRPV2 for normal homeostasis, the mechanisms that control TRPV2 gating in response to pharmacological agonists, heating, membrane stretch, bioactive lipids and reactive oxygen species (ROS) remain poorly understood. Here we demonstrate that TRPV2 is functionally expressed in microglia (i.e., ‘brain macrophages’) and the microglia-like BV-2 cell line, and demonstrate that the gating of an endogenous TRPV2-like conductance is positively modulated by the bacterial toxin lipopolysaccharide (LPS), which is known to cause pro-inflammatory (M1) activation and increase ROS production by NADPH oxidase. To determine how TRPV2 gating is modulated by ROS, we recorded single channel activity in inside-out patches excised from HEK-293 cells expressing GFP-rTRPV2. Unitary currents elicited by the TRPV2 agonist 2-aminophenyl borinate (2-APB) or cannabidiol (CBD) are linear in monovalent recording solutions and give rise to an estimated unitary conductance of ~100pS, which is similar to TRPV1 but significantly smaller than TRPV3. Intriguingly, we find that although TRPV2 is insensitive to ROS (in the form of exogenously applied H2O2) alone, apparent open probability is synergistically enhanced when H2O2 is applied together with CBD. We identify two intracellular Cys residues that are necessary for TRPV2 responses to H2O2 sensitivity and find that these residues are located close to one another, albeit in different subunits, in the TRPV2 structure, suggesting that ROS promote the formation of an inter-subunit disulfide bond that alters sensitivity to pharmacological agonists. We hypothesize that ROS-dependent modulation of TRPV2 activity may be an important contributor to pro-inflammatory activation of microglia underline central nervous system diseases and that TRPV2 antagonism could be a useful therapeutic strategy in the treatment of neuroinflammation.

Ce travail de thèse est consacré au développement de biocapteurs électrochimiques en utilisant des argiles ou des hydroxydes doubles lamellaires (HDL), riches en fer, comme matrices d'immobilisation de l'hémoglobine (Hb). Le but était de mettre en évidence la contribution des propriétés redox de ces matériaux dans l'amélioration des performances des biocapteurs par un phénomène de catalyse redox. L'hémoglobine est une métalloprotéine qui contient des porphyrines au fer (hème) comme sous-unité prosthétique. Une orientation privilégiée de cette biomolécule à la surface d'une électrode permet le transfert direct d'électrons entre le site actif de la protéine et l'électrode. Les propriétés électro-catalytiques de l'Hb immobilisée ont été étudiées pour la réduction du peroxyde d'hydrogène et ont permis la réalisation de différents biocapteurs ampérométriques. Nous avons immobilisé l'Hb dans plusieurs argiles cationiques contenant du fer : la nontronite de Garfield, des montmorillonites ferrifères synthétiques ou naturelles, ainsi qu'une montmorillonite synthétique servant de référence. Les propriétés électrochimiques de ces argiles ont été évaluées en voltammétrie cyclique et en impédancemétrie, en relation avec leurs propriétés structurales. Les isothermes d'adsorption de l'Hb dans ces argiles ont été établis montrant une forte affinité de l'Hb pour la nontronite. Nous avons montré que les argiles riches en fer octaédrique, notamment la nontronite, améliorent le transfert direct d'électrons entre l'Hb et l'électrode. L'immobilisation de l'Hb dans des HDL, de compositions différentes (MgAl et ZnAl) a été réalisée par adsorption et coprécipitation. Il faut noter que le fer situé en site octaédrique dans les HDL (MgFe) n'est pas électroactif et ne peut donc pas intervenir dans le processus électro-enzymatique. Les caractérisations physico-chimiques et morphologiques des biohybrides Hb-HDL ont été faites par plusieurs techniques, comme la DRX, IR, UV, MEB et MET, montrant une dénaturation partielle de la structure tertiaire de la protéine par la formation de liaisons hydrogènes entre la biomolécule et les feuillets hydroxylés des HDL; ce qui limite l'accessibilité de l'hème au transfert électronique direct. Outre l'immobilisation de l'Hb dans les HDL, nous avons également intercalé une métalloporphyrine chargée négativement, la FeTSPP, dans trois HDL de compositions différentes : Zn2Al, Mg2Al et Zn2Cr et nous avons réalisé la première étude électrochimique avec ces matériaux.

With the increasing time people spend indoors, the indoor environment quality draws more and more attention. The concentration of indoor pollutants is usually much higher than outdoors, in which volatile organic compounds (VOCs) and mold/mildew are both major pollutants and cause many health problems to residents. Efforts devoted from academy and industry to protecting people from indoor environment problems are apparently not sufficient. Photocatalysts, such as TiO2, WO and ZnO, can absorb light photons and react with O2 and H2O to generate highly oxidative radicals, which can oxidize VOCs and disinfect microorganisms. Recently, this photocatalytic oxidation (PCO) technology has been intensively studied to reduce VOCs and disinfect bacteria in the indoor environment. Few papers address the indoor mold/mildew problem, and this research therefore endeavors to do so. The objectives are to evaluate the effectiveness of PCO technology to resist mold/mildew growth and prevent VOC emission from building materials under either UV or visible light irradiation. The models, including linear regression, logistic regression, and numerical model, are also built for interpreting experimental results and for predicting performance in application. The mold/mildew resistance of different PCO gels was examined using accelerated mold/mildew growth agar plate tests. These gels included TiO2 only and TiO2 in combination with H2O2 and with Ag. Without the application of PCO gels, no mold/mildew inhibition was observed from UV (365 nm) or visible light. Under UV light irradiation, the TiO2 gel achieved complete mold/mildew inhibition. Without light, a 12-day delay of mold growth was obtained using the Ag-TiO2/H2O2 gel. Under visible light irradiation, the Ag-TiO2/H2O2 gel was also the most effective PCO gel with a 8-day delay of mold growth, which, however, was shorter than the same gel in the condition of no light with a 10-day delay due to the light-induced deterioration of the Ag-TiO2. The reduction of VOC emission from PCO gel (TiO2 gel and Ag-TiO2/H2O2 gel) coated building materials under UV or visible light irradiation was also confirmed by small chamber tests (the Ag-TiO2/H2O2 gel with above 50% reduction of total VOC emission). A linear model was obtained for the Ag-TiO2/H2O2 gel in the condition of no light, with respect to the correlation between the delay of mold growth and the gel ingredients. A logistic model was created for predicting the probability of mold growth on different TiO2 gels with different UV light exposure time at different intensities. A numerical model was developed with better accuracy than the previous one for VOC emission from PCO gel coated building materials. This study showed that the PCO gel might be a promising multifunctional material in resisting mold/mildew growth and preventing VOC emission in the indoor environment (The TiO2 gel for complete mold/mildew inhibition and the Ag-TiO2/H2O2 gel for delay of mold growth in emergency situations and reduction of VOC emission from building materials). More stable Ag-TiO2 or other visible-light-driven photocatalysts are needed in future research because of the deterioration of the current one.

La vida aeróbica conlleva la formación de especies reactivas derivadas del oxígeno: el radical hidroxilo (OH·), el ión superóxido (O2·-) y el peróxido de hidrógeno (H2O2). En Schizosaccharomyces pombe, dos rutas controlan las respuestas antioxidantes en respuesta a estrés oxidativo por H2O2: la del factor de transcripción Pap1 y la de la MAP quinasa Sty1. En esta tesis doctoral, hemos determinado que la activación de Pap1 se da en respuesta a dosis moderadas, pero no severas, de H2O2. Hemos identificado a la peroxirredoxina Tpx1 como sensor y transmisor de la señal de estrés oxidativo a Pap1. La inactivación temporal de Tpx1, durante estrés oxidativo severo, por oxidación a sulfínico de su cisteína catalítica inhibe la transmisión de señal a Pap1. En dichas condiciones, se activa la ruta de Sty1, que media la inducción de Srx1, cuya función es reducir y, con ello, reactivar a Tpx1. Finalmente, hemos estudiado el papel esencial de Tpx1 en aerobiosis. / Aerobic life involves formation of reactive oxygen species: hydroxyl radical (OH·), superoxide ion (O2·-) and hydrogen peroxide (H2O2). In Schizosaccharomyces pombe, two pathways respond to H2O2 and trigger independent antioxidant-gene responses: the Pap1 and the Sty1 pathways. In this thesis project, we have determined that the activation of the transcription factor Pap1 occurs only at low, but not elevated, H2O2 concentrations. We have identified the peroxiredoxin Tpx1 as a H2O2-sensor and redox activator of Pap1. The temporal inactivation of Tpx1 during severe oxidative stress, by oxidation of its catalytic cysteine to sulfinic acid, inhibits signal transduction to Pap1. During these conditions, the MAP kinase Sty1 is activated and expression of the sulfiredoxin Srx1 is triggered. Srx1 functions to reduce and thus reactivate Tpx1. Finally, we have analysed the essential function of Tpx1 in aerobiosis.

ABSTRACT According to the data of the Taiwan Air Quality Monitoring Network (TAQMN), the suspenden particulates decreases gradually with year at the Kao-Ping Air Quality Area, but the ozone increases with year and deteriorates. Therefore, the problem of the ozone is wating for solving at Kao-Ping Air Quality Area. Because the ground-level ozone has a relationship with NOx and VOC, they are thought to be the major precursors of the ozone. The concentration of the ozone is not linearly related with concentrations NOx and VOC. The precursors of the ozone affect the ground-level ozone, so the photochemical indicators are further developed in recent years. The photochemical indicators H2O2,HNO3 and NOy in this study in Kaohsiung area are analysed by criteria values (Sillman,1995 and 1997) and on-site sampling. The sampling sites are at Nan-Zih, Siao-Gang, Lin-Yuan and Chiao-Tou. The results can determine the major precursors forming ozone. In addition Smog Production Model (SPM) is also used to analyze the results. According to the analyses of the photochemical indicators, Nan-Zih, Siao-Gang, Lin-Yuan and Chiao-Tou are VOC-limited in the spring, summer, fall and winter.According to the analysis result of SPM, the four sites are also VOC-limited in four seasons.

Biological and physical chemistry treatment methods always are used to remove COD of organic wastewater contains PCB. The effect is not obvious when the compositions of pollutant are too refractory or complicated. The primary treatment method of wastewater containing copper is chemical coagulation/sedimentation and its disadvantage is producing a large of sludge. The objective of this study, using two combinative method of UV/H2O2-Ferrite Process and Fenton-Ferrite Process, is to remove organic compounds and heavy metal in real wastewater. Not only supernatant liquid could meet the standard of discharge wastewater but also produce general(non-hazardous) industrial wastes of heavy metal. The primary operation condition of Fenton and UV/H2O2 process, was ferrous ion and hydrogen peroxide concentration, pH, reaction time, and chemical dosing, searching best operation condition to combine with Ferrite Process. Operation of Fenton and UV/H2O2 process under acid condition (pH=2) and neutral condition (pH=8) showed the best operation condition of Fenton and UV/H2O2. The removal decreased when the dose of hydrogen peroxide was added too more or too less. As Fenton and UV/H2O2 process test finished, Ferrite Process is next used for treatment of heavy metal wastewater; Ferrite Process conducted as three stages and the operation conditions were controlled with temperature, pH and the ratio of Fe/M mole. The results showed that the best removal of treatment of copper containing wastewater by Ferrite Process achieved when the ratio of Fe/M mole was at 10. Treatment of PCB industrial real wastewater by Fenton-Ferrite Process and UV/H2O2-Ferrite Process which combined with Fenton, UV/H2O2 and Ferrite Process. The supernatant liquid containing organic compounds and heavy metal both could meet the standards of discharge wastewater and the sludge was judged with general(non-hazardous) wastes. The characteristic of the sludge were the diameter lattice less 100 nm and with magnetism and to develop recovery and utilization in a further work.

Previous investigations have demonstrated that reactive oxygen species such as hydrogen peroxide (H2O2) have the ability to alter electrophysiological and mechanical properties of rat ventricular cardiac myocytes. However, despite the breadth of the literature, there is little definitive consensus on the cellular mechanisms. The purpose of this study, therefore, was to study the cellular mechanism of action of H2O2 and test whether H2O2-mediated affects were partially a result of reverse-mode Na+/Ca2+ exchanger (NCX) activity. Unloaded cell shortening, intracellular Ca2+ transients, caffeine-induced Ca2+ transients, L-type Ca2+ channel recordings, and action potential waveforms were recorded in the presence of combinations of different compounds including Cd2+, H2O2, and KB-R7943. H2O2 was found to cause significant positive inotropy by an increase in contractility of 80 ± 20 % (n=6) and an increased amplitude of Ca2+ transients by 24 ± 14 % (n=8), relative to pre-treatment values. Interestingly, H2O2 caused an increase in contractility even in the presence of Cd2+ block from 4 ± 1 % (n=9) to 15 ± 3 % (n=5) of resting cell length. Using caffeine pulse experiments to induce unloading of the sarcoplasmic reticulum (SR), we found that 100µM H2O2 did not significantly alter SR Ca2+ load. Under control conditions, H2O2 significantly increased L-type Ca2+ currents while this H2O2-induced increase was not observed in myocytes pretreated with Cd2+. Positive inotropy in the presence of H2O2 was blocked using 10µM KB-R7943, a selective reverse-mode inhibitor of the NCX. However, it was found that 10µM KB-R7943 alone altered action potential profile and suppressed normal contraction. Altogether, the major finding of this study is that H2O2 has the ability to enhance myocardial contractility, even under conditions of L-type Ca2+ channel inhibition, through a mechanism that likely involves reverse-mode of the NCX. / Thesis (Master, Physiology) -- Queen's University, 2009-03-31 14:00:34.21

Στα έντομα, η κυτταροφαγία, διεργασία ανάλογη με αυτή των θηλαστικών, είναι μια σημαντική ανοσολογική απόκριση στην εισβολή παθογόνων και ρυθμίζεται από μια σειρά σηματοδοτικών μορίων. Στη μύγα της Μεσογείου έχει βρεθεί ότι συμμετέχουν οι κινάσες FAK, Src, MAPK και ο μεταγραφικός παράγοντας Elk-1. Στην εργασία αυτή, δείχτηκε με ανοσοκατακρήμνιση και συνεστιακή μικροσκοπία ότι η φωσφορυλιωμένη μορφή του Elk-1 συμπλοκοποιείται και συνεντοπίζεται μόνο με τη φωσφορυλιωμένη μορφή της FAK στη θέση Tyr925. Με ανάλογα πειράματα διαπιστώθηκε ότι οι κινάσες JNK και p38 συμπλοκοποιούνται και συγκατακρημνίζονται με την FAK, χωρίς όμως να συνεντοπίζονται. Με τον ίδιο τρόπο διαπιστώθηκε ότι η JNK και η p38 συμπλοκοποιούνται με την ERK1/2, χωρίς όμως να συνεντοπίζονται. Προφανώς τα μόρια αυτά δεν βρίσκονται σε άμεση επαφή μεταξύ τους και συμπλοκοποιούνται είτε μέσω της FAK, είτε μέσω τρίτων μορίων και όλα μαζί προσδένονται στην FAK. Τα φαγοκύτταρα των θηλαστικών, μακροφάγα και ουδετερόφιλα, καθώς και τα αιμοκύτταρα των εντόμων, παράγουν δραστικές μορφές οξυγόνου κατά την κυτταροφαγία, οι οποίες δρουν ως δεύτερα μηνύματα. Με κυτταρομετρία ροής διαπιστώθηκε ότι η E. coli επάγει τη σύνθεση Η2Ο2 από τα αιμοκύτταρα της μύγας της Μεσογείου. Ο ρυθμιστικός ρόλος του Η2Ο2 επιβεβαιώθηκε με τη χρήση αναστολέων των ενζύμων παραγωγής Ο2- και Η2Ο2, όπου παρατηρήθηκε αύξηση της κυτταροφαγίας. Με πειράματα ανοσοκατακρήμνισης, ανοσοαποτύπωσης και ανοσοφθορισμού φάνηκε ότι το ένζυμο σύνθεσης του Η2Ο2, η δεσμουτάση του υπεροξεικού ανιόντος (SOD), υπάρχει στο κυτταρόπλασμα και στην πλασματική μεμβράνη. Η αποσιώπηση της SOD με siRNA, αύξησε την κυτταροφαγία. Με ανοσοαποτύπωση διαπιστώθηκε ότι η αναστολή της παραγωγής του Η2Ο2 αύξησε τη φωσφορυλίωση της ERK1/2. Τέλος, με συνεστιακή μικροσκοπία φάνηκε ότι η SOD δεν συνεντοπίζεται με τη β υπομονάδα των ιντεγκρινών. Φαίνεται λοιπόν το Η2Ο2 να εμποδίζει την κυτταροφαγία μέσω ελέγχου της φωσφορυλίωσης της ERK1/2. / Phagocytosis is an important innate immune response against pathogen, with similar mechanisms in insects and mammals and is regulated by many different signalling molecules. In medfly Ceratitis capitata, focal adhesion kinase (FAK), Src, MAP kinases and Elk-1 transcription factor regulate this process. Co-immunoprecipitation and confocal microscopy analysis showed that pTyr925FAK associates and co-localizes with pElk-1, during phagocytosis of E. coli and S. aureus, by medfly haemocytes. Moreover, the physical association between JNK and p38 MAP kinases with FAK, was confirmed by immunoprecipitation, but confocal analysis revealed no co-localisation. Similar experiments for JNK and p38 with ERK1/2, revealed an association between JNK, p38 and ERK1/2 and no co-localisation. Apparently, these molecules do not interact directly but they appear to associate with each other indirectly, via FAK molecule or a third molecule and thus all together associate with FAK. Hydrogen peroxide (Η2Ο2) participates as a second messenger in cell signalling in either macrophages and polymorphonuclear cells or insect haemocytes. In this work, the role of Η2Ο2 was investigated, in E. coli phagocytosis by the medfly haemocytes. Block of H2O2 synthesis by specific enzymic inhibitors, namely N-ethylmaleimide (ΝΕΜ) for NADPH oxidase and diethyldithiocarbamate (DDC) for SOD, resulted in the increase of E. coli phagocytosis. Immunoblot analysis, flow cytometry and confocal microscopy, revealed the constitutive expression of SOD, in the medfly haemocytes. Phagocytosis increased by small interfering RNA (siRNA) for SOD, revealing the active involvement of SOD and Η2Ο2. Immunoblot analysis showed an increase of the ERK1/2 phosphorylation, in the presence of the above H2O2 synthesis enzymic inhibitors. In addition, confocal microscopy showed no co-localization of SOD with β integrin subunit. It appears that SOD participates in the regulation of bacterial phagocytosis, due to involvement of the produced Η2Ο2 in the differential phosphorylation of MAP kinases.