Control of cell division in Escherichia coli: regulation of transcription of ftsQA involves both rpoS and SdiA-mediated autoinduction.

The conditioning of culture medium by the production of growth-regulatory substances is a well-established phenomenon with eukaryotic cells. It has recently been shown that many prokaryotes are also capable of modulating growth, and in some cases sensing cell density, by production of extracellular signaling molecules, thereby allowing single celled prokaryotes to function in some respects as multicellular organisms. As Escherichia coli shifts from exponential growth to stationary growth, many changes occur, including cell division leading to formation of short minicells and expression of numerous genes not expressed in exponential phase. An understanding of the coordination between the morphological changes associated with cell division and the physiological and metabolic changes is of fundamental importance to understanding regulation of the prokaryotic cell cycle. The ftsQA genes, which encode functions required for cell division in E. coli, are regulated by promoters P1 and P2, located upstream of the ftsQ gene. The P1 promoter is rpoS-stimulated and the second, P2, is regulated by a member of the LuxR subfamily of transcriptional activators, SdiA, exhibiting features characteristic of an autoinduction (quorum sensing) mechanism. The activity of SdiA is potentiated by N-acyl-homoserine lactones, which are the autoinducers of luciferase synthesis in luminous marine bacteria as well as of pathogenesis functions in several pathogenic bacteria. A compound(s) produced by E. coli itself during growth in Luria Broth stimulates transcription from P2 in an SdiA-dependent process. Another substance(s) enhances transcription of rpoS and (perhaps indirectly) of ftsQA via promoter P1. It appears that this bimodal control mechanism may comprise a fail-safe system, such that transcription of the ftsQA genes may be properly regulated under a variety of different environmental and physiological conditions.

Haploidy and androgenesis in Drosophila.

Adrogenesis, development from paternal but not maternal chromosomes, can be induced to occur in some organisms, including vertebrates, but has only been reported to occur naturally in interspecific hybrids of the Sicilian stick insect. Androgenesis has not been described previously in Drosophila. We now report the recovery of androgenetic offspring from Drosophila melanogaster females mutant for a gene that affects an oocyte- and embryo-specific alpha-tubulin. The androgenetic exceptions are X,X diploid females that develop from haploid embryos and express paternal markers on all 4 chromosomes. The exceptional females arise by fusion of haploid cleavage nuclei or failure of newly replicated haploid chromosomes to segregate, rather than fusion of two inseminating sperm. The frequency of androgenetic offspring is greatly enhanced by a partial loss-of-function mutant of the NCD (nonclaret disjunctional) microtubule motor protein, suggesting that wild-type NCD functions is pronuclear fusion. Diploidization of haploid paternal chromosome complements results in complete genetic homozygosity, which could facilitate studies of gene variation and mutational load in populations.

Reconstitution of p53-ubiquitinylation reactions from purified components: the role of human ubiquitin-conjugating enzyme UBC4 and E6-associated protein (E6AP).

The E6 protein of the high-risk human papillomaviruses inactivates the tumor suppressor protein p53 by stimulating its ubiquitinylation and subsequent degradation. Ubiquitinylation is a multistep process involving a ubiquitin-activating enzyme, one of many distinct ubiquitin-conjugating enzymes, and in certain cases, a ubiquitin ligase. In human papillomavirus-infected cells, E6 and the E6-associated protein are thought to act as a ubiquitin-protein ligase in the ubiquitinylation of p53. Here we describe the cloning of a human ubiquitin-conjugating enzyme that specifically ubiquitinylates E6-associated protein. Furthermore, we define the biochemical pathway of p53 ubiquitinylation and demonstrate that in vivo inhibition of various components in the pathway leads to an inhibition of E6-stimulated p53 degradation.

Comparison of the defensive elicitation activity of cerato-populin and cerato-platanin: a structural model

Plants can defend themselves from potential pathogenic microorganisms relying on a complex interplay of signaling pathways: activation of the MAPK cascade, transcription of defense related genes, production of reactive oxygen species, nitric oxide and synthesis of other defensive compounds such as phytoalexins. These events are triggered by the recognition of pathogen’s effectors (effector-triggered immunity) or PAMPs (PAMP-triggered immunity). The Cerato Platanin Family (CPF) members are Cys-rich proteins secreted and localized on fungal cell walls, involved in several aspects of fungal development and pathogen-host interactions. Although more than hundred genes of the CPF have been identified and analyzed, the structural and functional characterization of the expressed proteins has been restricted only to few members of the family. Interestingly, those proteins have been shown to bind chitin with diverse affinity and after foliar treatment they elicit defensive mechanisms in host and non-host plants. This property turns cerato platanins into interesting candidates, worth to be studied to develop new fungal elicitors with applications in sustainable agriculture. This study focus on cerato-platanin (CP), core member of the family and on the orthologous cerato-populin (Pop1). The latter shows an identity of 62% and an overall homology of 73% with respect to CP. Both proteins are able to induce MAPKs phosphorylation, production of reactive oxygen species and nitric oxide, overexpression of defense’s related genes, programmed cell death and synthesis of phytoalexins. CP, however, when compared to Pop1, induces a faster response and, in some cases, a stronger activity on plane leaves. Aim of the present research is to verify if the dissimilarities observed in the defense elicitation activity of these proteins can be associated to their structural and dynamic features. Taking advantage of the available CP NMR structure, Pop1’s 3D one was obtained by homology modeling. Experimental residual dipolar couplings and 1H, 15N, 13C resonance assignments were used to validate the model. Previous works on CPF members, addressed the highly conserved random coil regions (loops b1-b2 and b2-b3) as sufficient and necessary to induce necrosis in plants’ leaves: that region was investigated in both Pop1 and CP. In the two proteins the loops differ, in their primary sequence, for few mutations and an insertion with a consequent diversification of the proteins’ electrostatic surface. A set of 2D and 3D NMR experiments was performed to characterize both the spatial arrangement and the dynamic features of the loops. NOE data revealed a more extended network of interactions between the loops in Pop1 than in CP. In addition, in Pop1 we identified a salt bridge Lys25/Asp52 and a strong hydrophobic interaction between Phe26/Trp53. These structural features were expected not only to affect the loops’ spatial arrangement, but also to reduce the degree of their conformational freedom. Relaxation data and the order parameter S2 indeed highlighted reduced flexibility, in particular for loop b1-b2 of Pop1. In vitro NMR experiments, where Pop1 and CP were titrated with oligosaccharides, supported the hypothesis that the loops structural and dynamic differences may be responsible for the different chitin-binding properties of the two proteins: CP selectively binds tetramers of chitin in a shallow groove on one side of the barrel defined by loops b1-b2, b2-b3 and b4-b5, Pop1, instead, interacts in a non-specific fashion with oligosaccharides. Because the region involved in chitin-binding is also responsible for the defense elicitation activity, possibly being recognized by plant's receptors, it is reasonable to expect that those structural and dynamic modifications may also justify the different extent of defense elicitation. To test that hypothesis, the initial steps of a protocol aimed to the identify a receptor for CP, in silico, are presented.

Avaliação do antagonismo do efeito do sódio sobre o tratamento de água residuária de Charqueada com elevada salinidade em reator anaeróbio de manta de lodo (UASB)

As águas residuárias provenientes da indústria do charque são conhecidas por apresentarem elevado teor de cloreto de sódio, aliado a grandes concentrações de matéria orgânica proveniente do sangue liberado ao longo do processo industrial. Esse tipo de água residuária apresenta potencial para degradação biológica, contudo, o cloreto de sódio, em concentração elevada, pode inibir a atividade dos microrganismos e, em alguns casos, levar sistemas biológicos à falência. No presente trabalho, foi avaliada a viabilidade de degradação anaeróbia de efluente sintético de Charqueada contendo elevado teor de cloreto de sódio, em reator anaeróbio tipo UASB (Upflow Anaerobic Sludge Blanket), em escala de laboratório. Foram utilizados 4 reatores, alimentados com água residuária sintética com características similares à água residuária de Charqueada. O reator 1 foi utilizado como controle, o reator 2 recebeu NaCl e os demais (3 e 4) foram operados na presença de NaCl acrescidos de: betaína e potássio com cálcio, respectivamente. Os compostos citados são conhecidos como antagonizantes, por possuirem capacidade de minimizar o efeito inibitório do sódio sobre o processo de digestão anaeróbia. Os reatores foram inoculados com lodo de reator UASB e submetidos à concentração de 5000 mg/L de matéria orgânica, como DQO. A carga orgânica aplicada foi de 5 Kg/m3.d e os reatores não suportaram tal carga. Reiniciou-se a operação com aumento progressivo da DQO de 500 a 2000 mg/L resultando em cargas orgânicas de 0,5 a 2,0 Kg/m3.d, respectivamente. Após estabilização dos reatores, iniciou-se a fase de introdução de cloreto de sódio (1.500 a 13.500 mg/L) e antagonizantes com aumento progressivo a cada fase. Na presença ou ausência de antagonizantes, os reatores 2, 3 e 4 não tiveram o desempenho alterado até a concentração de NaCl de 6000 mg/L. Na presença de 9000 mg/L de NaCl, a betaína se mostrou pouco efetiva como soluto compatível no reator 3 e os antagonizantes do reator 4, potássio e cálcio, apresentaram efeitos estimulatórios. As morfologias encontradas ao longo do experimento foram cocos, víbrios, bacilos, sarcinas, além de morfologias semelhantes a Methanosarcina sp. e Methanosaeta sp. O aumento da concentração de cloreto de sódio provocou a redição da população de Arqueas.

Mechanistic Importance of Redox Potentials and Conformational Flexibility in Electron-Transferring Flavoproteins

The mitochondrial matrix flavoproteins electron transfer flavoprotein (ETF) and electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) are responsible for linking fatty acid β-oxidation with the main mitochondrial respiratory chain. Electrons derived from flavoprotein dehydrogenases are transferred sequentially through ETF and ETF-QO to ubiquinone and then into the respiratory chain via complex III. In this study, the effects of changes in ETF-QO redox potentials on its activity and the conformational flexibility of ETF were investigated. ETF-QO contains one [4Fe-4S]2+,1+ and one flavin adenine dinucleotide (FAD). In the porcine protein, threonine 367 is hydrogen bonded to N1 and O2 of the flavin ring of the FAD. The analogous site in Rhodobacter sphaeroides ETF-QO is asparagine 338. Mutations N338T and N338A were introduced into the R. sphaeroides protein by site-directed mutagenesis to determine the impact of hydrogen bonding at this site on redox potentials and activity. FAD redox potentials were measured by potentiometric titration probed by electron paramagnetic resonance (EPR) spectroscopy. The N338T and N338A mutations lowered the midpoint potentials, which resulted in a decrease in the quinone reductase activity and negligible impact on disproportionation of ETF1e- catalyzed by ETF-QO. These observations indicate that the FAD is involved in electron transfer to ubiquinone, but not in electron transfer from ETF to ETF-QO. Therefore it is proposed that the iron-sulfur cluster is the immediate acceptor from ETF. It has been proposed that the αII domain of ETF is mobile, allowing promiscuous interactions with structurally different partners. Double electron-electron resonance (DEER) was used to measure the distance between spin labels at various sites and an enzymatically reduced FAD cofactor in Paracoccus denitrificans ETF. Two or three interspin distance distributions were observed for spin-labels in the αI (A43C) and βIII (A111C) domains, but only one is observed for a label in the βII (A210C) domain. This suggests that the αII domain adopts several stable conformations which may correspond to a closed/inactive conformation and an open/active conformation. An additional mutation, E162A, was introduced to increase the mobility of the αII domain. The E162A mutation doubled the activity compared to wild-type and caused the distance distributions to become wider. The DEER method has the potential to characterize conformational changes in ETF that occur when it interacts with various redox partners.

Responses to Domestic Violence Public Service Ads: Memory, Attitudes, Affect, and Individual Differences

Public service ads (PSAs) are an increasingly visible part of efforts to decrease the occurrence and consequences of domestic violence. Like other advertising, domestic violence PSAs are designed to grab attention, influence attitudes, and enhance memory for ad content. Over the years, images in domestic violence PSAs have changed substantially; agencies have started using pictures that generate emotions - either vivid negative images (bruised faces or body parts), or positive images (smiling faces) that contrast with the negative text. It is not clear, however, how different types of ad images influence memory for the message and attitudes about domestic violence, and what role affect may play in such responses. Moreover, the extent to which individual differences (trauma history, posttraumatic distress - PTSD symptoms) influence outcomes is not known. In three studies with undergraduate and community samples, using methods ranging from psychophysiology to self-report, the impact of images on attitudes and memory for ad content are investigated, also considering affect and individual differences. Results indicate graphic negative images enhanced memory for ad content, are rated as more persuasive, and are more likely to compel the viewer to act. Affective responses to ads also differed based on image type, and in some cases, partially mediated the relationship between ads and outcomes. Trends in the data suggest further study of the role of individual differences (trauma history, PTSD symptoms) is needed. This research provides information specifically relevant to the design of domestic violence public service campaigns and broadly relevant to understanding the role of emotional responses and individual differences on outcomes associated with public service ads.

An Empirical Comparison of Reuse in Embedded and Nonembedded Systems

High-quality software, delivered on time and budget, constitutes a critical part of most products and services in modern society. Our government has invested billions of dollars to develop software assets, often to redevelop the same capability many times. Recognizing the waste involved in redeveloping these assets, in 1992 the Department of Defense issued the Software Reuse Initiative. The vision of the Software Reuse Initiative was "To drive the DoD software community from its current "re-invent the software" cycle to a process-driven, domain-specific, architecture-centric, library-based way of constructing software.'' Twenty years after issuing this initiative, there is evidence of this vision beginning to be realized in nonembedded systems. However, virtually every large embedded system undertaken has incurred large cost and schedule overruns. Investigations into the root cause of these overruns implicates reuse. Why are we seeing improvements in the outcomes of these large scale nonembedded systems and worse outcomes in embedded systems? This question is the foundation for this research. The experiences of the Aerospace industry have led to a number of questions about reuse and how the industry is employing reuse in embedded systems. For example, does reuse in embedded systems yield the same outcomes as in nonembedded systems? Are the outcomes positive? If the outcomes are different, it may indicate that embedded systems should not use data from nonembedded systems for estimation. Are embedded systems using the same development approaches as nonembedded systems? Does the development approach make a difference? If embedded systems develop software differently from nonembedded systems, it may mean that the same processes do not apply to both types of systems. What about the reuse of different artifacts? Perhaps there are certain artifacts that, when reused, contribute more or are more difficult to use in embedded systems. Finally, what are the success factors and obstacles to reuse? Are they the same in embedded systems as in nonembedded systems? The research in this dissertation is comprised of a series of empirical studies using professionals in the aerospace and defense industry as its subjects. The main focus has been to investigate the reuse practices of embedded systems professionals and nonembedded systems professionals and compare the methods and artifacts used against the outcomes. The research has followed a combined qualitative and quantitative design approach. The qualitative data were collected by surveying software and systems engineers, interviewing senior developers, and reading numerous documents and other studies. Quantitative data were derived from converting survey and interview respondents' answers into coding that could be counted and measured. From the search of existing empirical literature, we learned that reuse in embedded systems are in fact significantly different from nonembedded systems, particularly in effort in model based development approach and quality where the development approach was not specified. The questionnaire showed differences in the development approach used in embedded projects from nonembedded projects, in particular, embedded systems were significantly more likely to use a heritage/legacy development approach. There was also a difference in the artifacts used, with embedded systems more likely to reuse hardware, test products, and test clusters. Nearly all the projects reported using code, but the questionnaire showed that the reuse of code brought mixed results. One of the differences expressed by the respondents to the questionnaire was the difficulty in reuse of code for embedded systems when the platform changed. The semistructured interviews were performed to tell us why the phenomena in the review of literature and the questionnaire were observed. We asked respected industry professionals, such as senior fellows, fellows and distinguished members of technical staff, about their experiences with reuse. We learned that many embedded systems used heritage/legacy development approaches because their systems had been around for many years, before models and modeling tools became available. We learned that reuse of code is beneficial primarily when the code does not require modification, but, especially in embedded systems, once it has to be changed, reuse of code yields few benefits. Finally, while platform independence is a goal for many in nonembedded systems, it is certainly not a goal for the embedded systems professionals and in many cases it is a detriment. However, both embedded and nonembedded systems professionals endorsed the idea of platform standardization. Finally, we conclude that while reuse in embedded systems and nonembedded systems is different today, they are converging. As heritage embedded systems are phased out, models become more robust and platforms are standardized, reuse in embedded systems will become more like nonembedded systems.

Pesquisa de marcadores sorológicos e moleculares da infecção pelo Vírus da Hepatite E (HEV) em indivíduos portadores do Vírus da Imunodeficiência Humana (HIV)

A infecção pelo HEV é reconhecida como um considerável problema de saúde pública em diversas regiões do mundo. Embora caracterizada como uma infecção benigna com um curso evolutivo autolimitado, recentes estudos têm mostrado sua evolução para cronicidade em indivíduos imunocomprometidos. Além disso, tem sido verificado que nesses indivíduos a infecção crônica pelo HEV pode evoluir para fibrose hepática progressiva, culminando com o desenvolvimento de cirrose. Não existem dados acerca da prevalência da infecção pelo HEV em pacientes infectados pelo HIV no Brasil, onde a circulação deste vírus tem sido demonstrada em diversos grupos de indivíduos imunocompetentes e, até mesmo, em alguns animais provenientes de diferentes regiões do país. Com base nisso, este trabalho teve como objetivo estimar a prevalência de marcadores sorológicos e moleculares da infecção pelo HEV, bem como a padronização de uma PCR em tempo real para a detecção e quantificação da carga viral do HEV na população de soropositivos da cidade de São Paulo. Foram incluídos neste estudo soro e plasma de pacientes infectados pelo HIV (n=354), que foram divididos em grupos de acordo com a presença ou ausência de coinfecção pelos vírus das hepatites B (HBV) e C (HCV). Essas amostras foram coletadas entre 2007 e 2013. Anticorpos anti-HEV IgM e IgG foram pesquisados pela técnica de ELISA (RecomWell HEV IgM/ IgG - MIKROGEN®), e, em alguns casos, confirmados por Immunoblotting (RecomLine HEV IgM/ IgG - MIKROGEN®). Todas as amostras foram submetidas à pesquisa de HEV RNA através da PCR em tempo real padronizada. Cerca de 72% dos indivíduos avaliados pertenciam ao sexo masculino. A média de idade entre a população analisada foi de 48,4 anos. Os anticorpos anti-HEV IgM e IgG foram encontrados em 1,4% e 10,7% dos indivíduos dessa população, respectivamente. Apenas dois pacientes apresentaram positividade simultânea para anti-HEV IgM e IgG. Não houve diferença estatisticamente relevante quanto à presença de marcadores sorológicos nos grupos de estudo. Além disso, foi detectado o HEV RNA em 10,7% das amostras analisadas, entre as quais, seis apresentaram simultaneamente algum marcador sorológico (5 anti-HEV IgG e 1 IgM). A presença deste marcador foi predominante no grupo de pacientes com coinfecção pelo HCV. Através deste trabalho pôde-se constatar, portanto, que o HEV é circulante entre a população de infectados pelo HIV em São Paulo, e que o seguimento desses pacientes se faz necessário dado a possibilidade de progressão para infecção crônica e cirrose

An Analysis of U.S. Air Force Policy and Installation CO2 Emissions to Determine Best Practices for the Implementation of Executive Order 13514

United States Air Force (USAF) energy policy is a measured but aggressive response to federal energy policy guidance. Previous USAF efforts, like those of the federal government, focused primarily on energy intensity reduction, cost, and BTU savings, and in certain cases have resulted in facility greenhouse gas (GHG) emission reductions. The USAF now faces the challenge of integrating GHG reduction goals and inventory requirements set forth in Executive Order 13514. Using USAF reported energy consumption data, facility GHG emission estimates have been synthesized to identify trends and elucidate existing energy best practices to be applied as part of overarching USAF GHG mitigation efforts and to highlight areas of possible concern for the integration of EO 13514 into operational USAF policy.

The comparison of maximal and endurance strength of quadriceps femori in trained and untrained elderly

The purpose of this study was to examine the differences in knee extensor maximal and endurance strength in elderly. Sixteen healthy elderly served as subjects, eight of them trained , age 61.0±8.9 yrs; height, 170.6±6.8 cm; weight, 71.8±11.7 kg [mean ± standard deviation] and eight untrained 61.4±8.1 yrs, height 174.6±7.4 cm; weight 83.9 ±14.2 kg. Maximal strength in single leg extension exercise was measured unilaterally with the dominant leg until the subjects reached their 1 Repetition Maximum (RM) covering the full Range of Motion (ROM). Muscular endurance was obtained with a load of 75% of 1-RM for 3 consecutive sets, with 2 min rest periods till failure. Load at 1 RM was lower in absolute terms in untrained, but not significant, while the relative 1-RM test was significantly lower in untrained subjects (0.20 vs. 0.25 kg load/kg body weight) (p<0.05). The number of repetitions and amount of weight lifted performed of all 3 sets was higher in trained subjects, but not significant. In the trained group both repetitions and the load managed in the third set was significant lower compared with the first two sets. The result that maximal force output is more affected compared to muscular endurance in these subjects might be due to the habitual use of quadriceps femoris muscles during activity of daily living in both trained and untrained elderly.

Use of Tablet Pcs in Higher Education: A new Strategy for Training Engineers in European Bachelors and Masters Programmes

The use of technology in classrooms in Spanish universities has been following an upward path, and in many cases technological devices are substituting other materials that until now have been used, such as books, notebooks and so on. Step by step in higher education, more of these latest generationdevices are being used, and are providing significant improvements in training. Nowadays, there are Spanish universities that use tablets, a device with multiple applications for teaching as well as for students to study differently. They are definitely a notable innovation that will gradually become incorporated into university life. Tablet PCs make teaching more dynamic and available to students through the use of up to date digital materials, something which is key in training engineers. This paper presents their different functions employed in three Spanish universities to support teachingin engineering degrees and masters using the tablet PC, and their impact on the training process. Possible uses in specific programs like the Erasmus Masters Programmes are also assessed. The main objective of using tabletsis to improve the academic performance of students through the use of technology.

Magnetars: Properties, Origin and Evolution

Magnetars are neutron stars in which a strong magnetic field is the main energy source. About two dozens of magnetars, plus several candidates, are currently known in our Galaxy and in the Magellanic Clouds. They appear as highly variable X-ray sources and, in some cases, also as radio and/or optical pulsars. Their spin periods (2–12 s) and spin-down rates (∼10−13–10−10 s s−1) indicate external dipole fields of ∼1013−15 G, and there is evidence that even stronger magnetic fields are present inside the star and in non-dipolar magnetospheric components. Here we review the observed properties of the persistent emission from magnetars, discuss the main models proposed to explain the origin of their magnetic field and present recent developments in the study of their evolution and connection with other classes of neutron stars.

Epithelial Ovarian Cancers and Endometriosis

Aims: To determine the prevalence of endometriosis in epithelial ovarian cancers (EOC) and the association among their histological subtypes and with endometrial carcinoma. Methods: An observational cohort study performed in 192 patients operated on for EOC, 30 women with atypical endometriosis and 17 with p53 positive endometriosis. Data on associated endometriosis and endometrial carcinomas, histological subtypes, tumor stage, clinical and pathological characteristics and survival were analyzed. Results: Twenty cases of EOC (10.4%) had also endometriosis (12.7 in borderline and 9.3% in invasive cases), being a synchronous finding in most cases. Endometriosis associated with serous or mucinous EOC was observed in 2.2 and 2.7% of cases, respectively. However, this association was observed in 50 of endometrioid and 23% of clear cell EOC. Age, parity and tumor stage were lower in endometriosis-associated EOC patients; and all associated cases were type I (Kurman and Shih's classification) and showed better results in survival rate. Endometrial carcinoma was more frequently associated with endometrioid EOC (25%). Conclusions: There is a significant association between endometriosis, including atypical forms, and endometrioid and clear cell carcinomas, but not with other EOC histotypes. The presence of endometriosis in EOC suggests a better prognosis and an intermediate stage within the progression endometriosis-carcinoma.

Co-encapsulation of enzymes and antibodies for chemical deactivation of pathogens on paper

Le papier bioactif est obtenu par la modification de substrat du papier avec des biomolécules et des réactifs. Ce type de papier est utilisé dans le développement de nouveaux biocapteurs qui sont portables, jetables et économiques visant à capturer, détecter et dans certains cas, désactiver les agents pathogènes. Généralement les papiers bioactifs sont fabriqués par l’incorporation de biomolécules telles que les enzymes et les anticorps sur la surface du papier. L’immobilisation de ces biomolécules sur les surfaces solides est largement utilisée pour différentes applications de diagnostic comme dans immunocapteurs et immunoessais mais en raison de la nature sensible des enzymes, leur intégration au papier à grande échelle a rencontré plusieurs difficultés surtout dans les conditions industrielles. Pendant ce temps, les microcapsules sont une plate-forme intéressante pour l’immobilisation des enzymes et aussi assez efficace pour permettre à la fonctionnalisation du papier à grande échelle car le papier peut être facilement recouvert avec une couche de telles microcapsules. Dans cette étude, nous avons développé une plate-forme générique utilisant des microcapsules à base d’alginate qui peuvent être appliquées aux procédés usuels de production de papier bioactif et antibactérien avec la capacité de capturer des pathogènes à sa surface et de les désactiver grâce à la production d’un réactif anti-pathogène. La conception de cette plate-forme antibactérienne est basée sur la production constante de peroxyde d’hydrogène en tant qu’agent antibactérien à l’intérieur des microcapsules d’alginate. Cette production de peroxyde d’hydrogène est obtenue par oxydation du glucose catalysée par la glucose oxydase encapsulée à l’intérieur des billes d’alginate. Les différentes étapes de cette étude comprennent le piégeage de la glucose oxydase à l’intérieur des microcapsules d’alginate, l’activation et le renforcement de la surface des microcapsules par ajout d’une couche supplémentaire de chitosan, la vérification de la possibilité d’immobilisation des anticorps (immunoglobulines G humaine comme une modèle d’anticorps) sur la surface des microcapsules et enfin, l’évaluation des propriétés antibactériennes de cette plate-forme vis-à-vis l’Escherichia coli K-12 (E. coli K-12) en tant qu’un représentant des agents pathogènes. Après avoir effectué chaque étape, certaines mesures et observations ont été faites en utilisant diverses méthodes et techniques analytiques telles que la méthode de Bradford pour dosage des protéines, l’électroanalyse d’oxygène, la microscopie optique et confocale à balayage laser (CLSM), la spectrométrie de masse avec désorption laser assistée par matrice- temps de vol (MALDI-TOF-MS), etc. Les essais appropriés ont été effectués pour valider la réussite de modification des microcapsules et pour confirmer à ce fait que la glucose oxydase est toujours active après chaque étape de modification. L’activité enzymatique spécifique de la glucose oxydase après l’encapsulation a été évaluée à 120±30 U/g. Aussi, des efforts ont été faits pour immobiliser la glucose oxydase sur des nanoparticules d’or avec deux tailles différentes de diamètre (10,9 nm et 50 nm) afin d’améliorer l’activité enzymatique et augmenter l’efficacité d’encapsulation. Les résultats obtenus lors de cette étude démontrent les modifications réussies sur les microcapsules d’alginate et aussi une réponse favorable de cette plate-forme antibactérienne concernant la désactivation de E. coli K-12. La concentration efficace de l’activité enzymatique afin de désactivation de cet agent pathogénique modèle a été déterminée à 1.3×10-2 U/ml pour une concentration de 6.7×108 cellules/ml de bactéries. D’autres études sont nécessaires pour évaluer l’efficacité de l’anticorps immobilisé dans la désactivation des agents pathogènes et également intégrer la plate-forme sur le papier et valider l’efficacité du système une fois qu’il est déposé sur papier.