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The object of this thesis was to examine microbial interactions in offshore crude oil storage systems with special reference to the role played by the sulphate-reducing bacteria (SRB). The aim was to characterise the SRB present in such systems; to isolate and characterise crude oil-degrading bacteria and to develop simple models of the system. SRB were shown to be present in samples from offshore by the detection of high levels of SRB and sulphide, and of depleted sulphate levels. SRB were enriched for, isolated and characterised from offshore oil storage facilities and pure cultures of the organisms <i>Desulfovibrio desulphuricans, Desulfovibrio sapovorans, Desulfobacter postgatei</i> and <i>Desulfobulbus propionicus</i> were isolated. <i>Desulfobacter</i> was shown to be the key organism in this environment, responsible for the terminal oxidation of acetate produced from the incomplete oxidation of higher fatty acids by the <i>Desulfovibrio</i> spp. and the <i>Desulfobulbus</i>. The enrichment, isolation and partial characterisation of oil-degrading bacteria of the genera <i>Pseudomonas</i> and <i>Micrococcus</i> was also carried out. These organisms were shown to use both aliphatic and aromatic components of crude oil. The breakdown of hydrocarbons provides both the anaerobic conditions and carbon sources necessary for the growth of SRB. Liquid and gel-stabilised model systems in which both the temporal and spatial development of oil-degrading communities (including SRB) were constructed.

L’Insulin Degrading Enzyme (IDE) est une protéase dont les mécanismes de fonctionnements ne sont pas encore complètement élucidés.Dans ce but, nous avons identifié un homologue d’IDE chez la levure Schizosaccharomyces pombe (S. pombe) : iph (Insulinase Pombe Homologue), et mis en évidence un lien entre Iph et la voie TOR (Target of Rapamycin) lors d’un stressprotéotoxique.La voie TOR comme les voies de vieillissement et de réponse au stress sont régulées par la présence de nutriments dans le milieu. Dans cette optique, nous nous sommes intéressés chez S. Pombe à la durée de vie chronologique qui, dans une souche sauvage, augmente lors d’une restriction en glucose.Cependant, les levures invalidées pour iph perdent cette capacité, et présentent une DVC identique indépendamment de la concentration du glucose dans le milieu.L’ensemble de ces résultats a permis de démontrer que la protéine Iph régule négativement la voie TOR, qui elle même favorise la survie lors d’un stress protéotoxique et le vieillissement des cellules. / Insulin Degrading Enzyme (IDE) is a 110 kDa protease whose function is not completely elucidated.To this aim, we have identified a homologue of IDE in the yeast Schizosaccharomyces pombe (S. pombe) : iph (Insulinase Pombe Homologue), and we have pointed out a link between Iph and the TOR (Target of Rapamycin) pathway during proteotoxic stress.The TOR pathway- like the pathways of ageing and the stress response- are regulated by the presence of nutrients in the environment.Knowing this, we were interested in S. Pombe chronological life span that increases in the case of glucose restriction in the wildtype strain. However, the yeast cells deleted for iph loose this capacity and show a lifespan chronology that is identical independently of the glucose concentration in the environment.Taking together these results show that the protein Iph regulates negatively the TOR pathway, which by oneself favours the survival during proteotoxic stress and ageing of the cells.

Fluorotelomer alcohols (FTOHs, F(CF2)nCH2CH2OH) are emerging contaminants in the environment. Biodegradation of 6:2 and 8:2 FTOHs has been intensively studied using soils and activated sludge. However, little is known about the bacteria responsible for biotransformation of FTOHs. This study deciphered factors affecting biodefluorination of FTOHs and their metabolites, and developed three effective FTOH-degrading consortia. Two alkane-degrading Pseudomonas strains (P. oleovorans and P. butanovora) can defluorinate 4:2, 6:2 and 8:2 FTOHs, with a higher degree of defluorination for 4:2 FTOH. According to the identified metabolites, P. oleovorans transformed FTOHs via two pathways I and II. Pathway I led to formation of x:2 ketone (x = n-1), x:2 sFTOH and perfluorinated carboxylic acids (PFCAs). Pathway II resulted in the formation of x:3 polyfluorinated acid and relatively minor shorter-chain PFCAs. Conversely, P. butanovora transformed FTOHs by pathway I only. Mycobacterium vaccae JOB5 (a C1-C22alkane-degrading bacterium) and P. fluorescens DSM 8341 (a fluoroacetate-degrading bacterium) can transform 6:2 FTOH via both pathways I and II with the formation of odd-numbered short-chain PFCAs. In the presence of dicyclopropylketone or formate, P. oleovorans transformed 6:2 FTOH six times faster and produced odd-numbered PFCAs. P. butanovora, utilized both pathways I and II in the presence of lactate, and it also produced odd-numbered PFCAs. Unlike P. oleovorans, P. fluorescens DSM 8341 could slightly convert 5:3 polyfluorinated acid (a key metabolite during 6:2 FTOH degradation, [F(CF2)5CH2CH2COOH]) to 4:3 acid and PFPeA via one-carbon removal pathways. Three FTOH-degrading consortia transformed FTOHs, with enhanced removal of FTOHs in the presence of n-octane. A higher copy number of alkB gene was found to correspond to better removal of FTOHs, suggesting that alkane-degrading bacteria might be the key degraders in the enrichments. The three enrichment cultures showed a similar microbial community structure. This is the first study reporting that pure strains of alkane- and fluoroacetate-degrading bacteria can bio-transform FTOHs via different or preferred transformation pathways to remove multiple –CF2– groups from FTOHs to form shorter-chain PFCAs, and to other perfluorinated acids. The results of this study also suggest that enhanced FTOH biodegradation is possible through co-substrate addition and/or using enrichment cultures.

The aim of this investigation was to assess if there was a correlation between touch avoidance and hierarchical position, perceived degradation, number of years spent in jail and age amongst men at a correctional institution. In addition, a possible correlation between hierarchical position and the amount of perceived degrading treatment was also explored. In the collection of the data a questionnaire containing 27 open and closed answer alternatives was utilized. A multiple regressional analysis was conducted to find possible correlations between touch avoidance and the other underlying variables. Also an independent t-test explored the possible effects of the control variables: place of birth and girlfriend. A correlational analysis was applied to investigate the other two control variables: physical and psychological abuse during childhood. An oneway-ANOVA-test was used to investigate the possible correlation between hierarchical position and the amount of perceived degrading treatment. The results of the study showed that a high amount of degrading treatment, a low hierarchical position and the longer the time served correlated with a high degree of touch avoidance. Age proved to have no correlation with touch avoidance, which is contrary to previous research. Regarding the inmates’ hierarchical position and the amount of perceived degrading treatment, a negative correlation was found; the higher hierarchical position an inmate had, the smaller was the amount of degrading treatment he was subjected to. Keywords: Touch avoidance, hierarchies, degrading treatment, inmates, prison

<p>The aim of this investigation was to assess if there was a correlation between touch avoidance and hierarchical position, perceived degradation, number of years spent in jail and age amongst men at a correctional institution. In addition, a possible correlation between hierarchical position and the amount of perceived degrading treatment was also explored. In the collection of the data a questionnaire containing 27 open and closed answer alternatives was utilized. A multiple regressional analysis was conducted to find possible correlations between touch avoidance and the other underlying variables. Also an independent t-test explored the possible effects of the control variables: place of birth and girlfriend. A correlational analysis was applied to investigate the other two control variables: physical and psychological abuse during childhood. An oneway-ANOVA-test was used to investigate the possible correlation between hierarchical position and the amount of perceived degrading treatment. The results of the study showed that a high amount of degrading treatment, a low hierarchical position and the longer the time served correlated with a high degree of touch avoidance. Age proved to have no correlation with touch avoidance, which is contrary to previous research. Regarding the inmates’ hierarchical position and the amount of perceived degrading treatment, a negative correlation was found; the higher hierarchical position an inmate had, the smaller was the amount of degrading treatment he was subjected to.</p><p>Keywords: Touch avoidance, hierarchies, degrading treatment, inmates, prison</p>

Textile dyes are molecules designed to impart a permanent colour to textile fabrics. They pose an environmental problem because they are toxic and they decrease the aesthetic value of rivers and lakes. Current technologies for dye removal cannot remove all classes of dyes and two or more technologies are usually combined to achieve statisfactory decolourization efficiencies. Lignin-degrading enzymes like laccases are potential technologies for dye decolourization and decolourization with immobilized laccase has been intensively investigated. The majority of those studies however have focused on dye disappearance and several reported that significant dye adsorption had occured during the dye removal, making the role of the enzyme unclear. Moreover, textile wastewaters contain auxiliary chemicals that can impact enzymatic dye decolourization and very few studies have evaluated the impact of those substances on laccase. This research evaluated the feasibility of treating dye-contaminated textile wastewaters with an immobilized laccase system. The first sub-objective was to examined the decolourization of Reactive blue 19 (an anthraquinone dye) by Trametes versicolor laccase immobilized on controlled porosity carrier (CPC) silica beads and the second was to analyze the kinetic effects of a non-ionic surfactant Merpol, sodium sulfate, and sodium chloride on laccase decolourization of Reactive blue 19. Decolourization of Reactive blue 19 by immobilized laccase was mainly enzymatic although dye some adsorption occurred. Decolourization led to less toxic by-products from azo and indigoid dyes whereas increased toxicity was observed for anthraquinone dyes. The feasibility of immobilizing laccase on poly(methyl methacrylate) (PMMA) through its sugar residues with a simple procedure was demonstrated and the mass of enzyme immobilized compared well with other commercial acrylic supports. The decolorization of Reactive blue 19 by laccase was inhibited by the non-ionic surfactant, Merpol by substrate depletion. A model describing this inhibition was developed and was validated by a saturated equilibrium binding experiment. While sodium sulfate (ionic strength) had no effect on either ABTS oxidation or dye decolourization, sodium chloride inhibited laccase during dye decolourization and the type and nature of the inhibition depended on the substrate. With ABTS, the inhibition was hyperbolic non-competitive whereas it was parabolic mixed with Reactive blue 19. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2009-06-16 16:58:47.753

De nombreux insectes s’avèrent être des ravageurs de culture, pouvant de surcroît transmettre des pathogènes aux plantes et ainsi causer des dégâts d’importance économique notables. Leur contrôle repose essentiellement sur l’utilisation d’insecticides, mais cela pose problème en termes de pollution de l’environnement, d’effets non désirés sur les espèces non-cibles, d’apparition de populations d’insectes résistants aux insecticides, sans parler de leur toxicité pour l’homme. L’olfaction joue un rôle clef dans le développement de nombreux comportements chez les insectes, comme la recherche de la plante nourricière ou du partenaire sexuel, le repérage de sites de ponte ou de prédateurs. Leurs organes olfactifs portent les sensilles sensorielles dans lesquelles se déroulent les étapes de la réception du signal : les molécules odorantes pénètrent par les pores et sont transportées à travers la lymphe sensillaire par des "odorant binding proteins" jusqu’aux récepteurs olfactifs (Ors) avec lesquels elles interagissent pour déclencher la cascade de transduction, puis le signal olfactif est inactivé. Si les interactions odeurs/ORs sont largement étudiées et élucidées, il n’en est pas de même pour le transport et l’inactivation du signal. En particulier, les "odorant-degrading enzymes" (ODEs) qui seraient impliquées dans cette dernière étape, en dégradant les molécules odorantes en métabolites inactifs, i.e. ne pouvant plus stimuler les récepteurs. Les ODEs appartiennent à diverses familles d’enzymes de biotransformation, comme les cytochromes P450s (CYPs), les carboxylestérases (CCEs), les glutathion-S-transférases (GSTs), ou les UDP-glucosyltransférases (UGTs). La plupart sont exprimées fortement dans les antennes. Peu d’entre-elles ont été caractérisées fonctionnellement, principalement par des approches in vitro, peu d’études ont été réalisées in vivo avec des approches électrophysiologiques ou comportementales. Au cours de ma thèse, nous avons caractérisé deux CCEs antennaires, l’Estérase6 (Est6) et la « Juvenile Hormone Esterase duplication » (JHEdup), chez Drosophila melanogaster, en combinant des approches transcriptomiques et fonctionnelles. Nous avons montré que ces deux estérases étaient exprimées très fortement dans les antennes et capables de métaboliser in vitro certaines odeurs alimentaires émises par les fruits mûrs. Nous avons aussi démontré que ces deux estérases étaient impliquées in vivo dans les réponses physiologiques et comportementales à ces odorants, et qu’elles s’avèrent donc être des ODEs.. Pour deux ODEs candidates, Ugt35b (UGT) et Cyp308a1 (CYPs), nous avons établi leur patron d’expression dans les antennes afin de préciser les types de sensilles impliquées, en préliminaire à des études fonctionnelles plus ciblées. Enfin, pour ugt35b, cyp308a1 et jhedup, nous avons mis en évidence une expression dans différentes structures gustatives, posant la question de leur rôle possible dans le métabolisme de molécules sapides. Les quatre enzymes antennaires présentées ici ne sont que le début d’une longue liste d’ODEs candidates identifiées lors de l’analyse du transcriptome antennaire de D. melanogaster. Ce travail participe à une meilleure compréhension des mécanismes moléculaires impliqués dans le fonctionnement du système olfactif. Du point de vue appliqué, les ODEs pourraient constituer des cibles d’intérêt (via des inhibiteurs spécifiques par exemple) pour modifier des comportements olfacto-induits, et ce dans un contexte de contrôle de populations d’insectes ravageurs plus respectueux de l’environnement. Par ailleurs, les connaissances acquises sur les ODEs chez cette espèce modèle pourraient contribuer à leur caractérisation chez d’autres espèces, en particulier des ravageurs de cultures. / Insects can be hazardous crop pests that do not only feed on crops but also transmit plant pathogens, causing yearly a great economical damage. Pest control relies mainly on insecticides but an extensive use bears problems such as the pollution of environment, unpredictable effects on non-target species, an increase of insecticide resistant populations and toxicity for humans. Olfaction is fundamental for the implementation of many insect behaviours like host plant and mating partner foraging, identification of suitable oviposition sites and predator avoidance. Insects smell with hairshaped olfactory sensilla, which are located on their antennae and palps. These sensilla are the showplace of early olfactory processing involving several steps: the odor uptake through the sensillar pores and their transport through the sensillar lymph mediated by odorant binding proteins, the detection of odors by olfactory receptors (ORs) and eventually the inactivation of the olfactory signal. Odor/OR interactions have been intensely studied, contrary to odor transport and inactivation that remain not well understood. Odorant-degrading enzymes (ODEs) have been suggested to be responsible for odor inactivation by degrading odorants into inactive metabolites which no longer activate ORs. The ODEs identified to date belong to various biotransformation enzyme families, including cytochrome P450s (CYPs), carboxylesterases (CCEs), glutathione-S-transferases (GSTs), UDP-glucosyltransferases (UGTs). Most of them are highly expressed in insect antennae. To date, only some ODEs have been functionally characterized, most of them in vitro using recombinant protein and showing their ability to efficiently metabolize various odorant molecules. Only a very few studies were investigating ODE function in vivo using electrophysiological and behavioural approaches. In this thesis we functionally characterize two antennal CCEs, Esterase6 (Est6) and Juvenile Hormone Esterase duplication (JHEdup), in the insect model Drosophila melanogaster combining transcriptomic, in vitro and in vivo approaches. We found that both CCEs are highly expressed in antennae and are able to efficiently metabolize certain odors emitted by rotting fruits in vitro. Furthermore, we showed that both are involved in physiological and behavioural responses to these odors. Therefore we propose Est6 and JHEdup as sensillar candidate ODEs. Moreover, we investigated the precise antennal gene expression pattern in toto for two antennal biotransformation enzymes belonging to other classes, Ugt35b (UGT) and Cyp308a1 (CYPs), which will be helpful for further investigations in order to clarify their potential role in olfaction. In case of three ODE candidate genes (ugt35b, cyp308a1 and jhedup) we discovered an interesting expression pattern in various gustatory organs posing new questions about additional functions of these antennal enzymes in taste processing. The antennal enzymes discussed in this thesis are only four of many candidate ODEs that we identified in the antennal transcriptome of the fruit fly. These candidates comprise also enzymes that belong to other classes such as GSTs, aldehyde oxidases, alcohol dehydrogenases or lipases. This work contributes to a deeper understanding of the insect olfactory system including its molecular actors. From an applied point of view ODEs are interesting targets to modify odorant-driven insect behaviours. The identification of specific ODE inhibitors that could interfere with insect ability to respond to environmental olfactory cues, emitted by mating partners or host plants, would contribute to a broader variety of “eco-friendly” olfactory-based insect pest control strategies. In the future the obtained knowledge in the insect model Drosophila will contribute to the characterization of ODEs in different hazardous insect pests which will be the next step to develop new inhibitor-based strategies.