Dissertations / Theses on the topic 'Bacterial metabolic activity'
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Wos, Melissa Louise, and n/a. "Methods For Understanding Bacterial Metabolic Activity In Activated Sludge." Griffith University. School of Environmental Engineering, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20061031.151641.
Full textWos, Melissa Louise. "Methods For Understanding Bacterial Metabolic Activity In Activated Sludge." Thesis, Griffith University, 2005. http://hdl.handle.net/10072/367303.
Full textThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environmental Engineering
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Aguirre, Arturo Leonardo. "Investigating quinazoline-2,4-dione and fluoroquinolone scaffolds for antibiotic activity and metabolic stability." Diss., University of Iowa, 2019. https://ir.uiowa.edu/etd/6904.
Full textWinkler, Jonathan Alexander. "Improving antibiotic activity by manipulating bacterial reactive oxygen species metabolism." Thesis, Boston University, 2012. https://hdl.handle.net/2144/12675.
Full textThe discovery of antibiotics was one of the most important medical breakthroughs of the twentieth century, having a broad impact on overall life expectancy and public health. Unfortunately, antibiotic discovery has slowed significantly in recent times and has failed to match the rising incidence of antibiotic-resistant pathogens. Gram-negative pathogens are a particularly troublesome threat, primarily because these bacteria possess an outer membrane that prevents many antibiotics from accessing their primary cellular targets. While the discovery of novel antibiotics could help to address these issues, alternative strategies, such as improving the activity of preexisting antibiotics, are also needed. Bactericidal antibiotics have recently been shown to share a common mechanism of cell death, despite having different primary, cellular targets. This shared mechanism involves the metabolic production of reactive oxygen species (ROS), which can damage proteins, lipids, and nucleic acids, and can ultimately result in bacterial cell death. The body of work described here shows that this common mechanism can be exploited to improve antibiotic activity, regardless of the antibiotic's primary mode of action. First, I will describe how bacterial metabolism can be predictably perturbed to increase endogenous ROS production, and that increasing endogenous ROS is sufficient to enhance bacterial sensitivity to treatments with ROS-generating biocides, antibiotics, and immune cell attack. I will then describe work indicating that an ancient antimicrobial agent, silver salts, can also increase endogenous ROS production and potentiate the activity of multiple antibiotic classes. Furthermore, I show that silver salts can increase the outer membrane permeability of a Gram-negative organism. This property is exploited to enable vancomycin, an antibiotic that is specific for Gram-positive bacteria, to work against a Gram-negative organism. Together, this body of work demonstrates that bacterial ROS metabolism can be exploited effectively to enhance. antibiotic activity, which ultimately could result in the discovery and development of novel antimicrobial agents.
Muttray, Annette Friederike. "Population and metabolic activity dynamics of resin-acid-degrading bacteria as determined by the RNA, DNA ratio." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ61150.pdf.
Full textStadie, Jasmin [Verfasser], Rudi F. [Akademischer Betreuer] Vogel, and Siegfried [Akademischer Betreuer] Scherer. "Metabolic activity and symbiotic interaction of bacteria and yeasts in water kefir / Jasmin Stadie. Gutachter: Rudi F. Vogel ; Siegfried Scherer. Betreuer: Rudi F. Vogel." München : Universitätsbibliothek der TU München, 2013. http://d-nb.info/1046939858/34.
Full textTzimorotas, Dimitrios. "In vitro fermentation of various substrates by human faecal bacteria : Evaluation of type and dose of substrates as factors affecting faecal microbiota changes and metabolic activity." Thesis, University of Reading, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529948.
Full textFougy, Lysiane. "Les impacts de la réduction de la teneur en sel sur la conservation et les écosystèmes bactériens des chipolatas." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLA039/document.
Full textSalt content plays a key role in meat product preservation since it inhibits bacterial growth. However, dietary guidelines aim to reduce salt content in food. The objectives of this study were (1) to characterize the bacterial community of raw pork sausages and the spoilage phenomenon of these products under salt reduction conditions and (2) to correlate the organoleptic deterioration of the products to modifications in bacterial community.We first characterized the raw pork sausages spoilage by sensory and physicochemical analysis. The work demonstrates that spoilage intensity is greater under a reduced salt content, particularly when sausages are packaged under modified atmosphere. The spoilage is characterized by the production of sulfur, sour and rancid off-odors, a decrease in pH of the sausages and an increase of exudate production.At the same time, we described the bacterial diversity of spoiled sausages through 16S rRNA analysis. Abundance of bacterial species was quantified by qPCR. With these methods, we were able to distinguish the dominant population from the subdominant population. Reducing salt content causes an abundance imbalance between these two populations. This imbalance does not result from an increase of the dominant species; it results from a decrease in abundance of subdominant species.To understand the roles of these bacterial populations, we analyzed their metabolic activities by RNA-Seq approach. The works highlight a high metabolic activity of the subdominant species. When the salt concentration is lowest, the expression of Serratia sp. genes involved in the fermentation of pyruvate to produce ethanol, CO2 and acetate is most important. The acetate production may be connected to the spoilage defaults observed (decrease in pH, exudate production and sour off-odors).These studies reveal that salt reduction impacts the bacterial community of raw pork sausages (abundance and metabolic activities) and this disruption compromises the organoleptic quality of the products
Diawara, Bréhima. "Conservation de riz-paddy sous atmospheres controlees : aspects microbiologiques et consequences technologiques." Nantes, 1988. http://www.theses.fr/1988NANT2016.
Full textBarsotti, Vanessa. "Recherche et caractérisation de microorganismes dans les compartiments géologiques profonds." Phd thesis, Bordeaux 1, 2011. http://tel.archives-ouvertes.fr/tel-00688631.
Full textAubé, Johanne. "Structure et fonctionnement de tapis microbiens contaminés par des hydrocarbures." Thesis, Pau, 2014. http://www.theses.fr/2014PAUU3029/document.
Full textUbiquist and very ancient, the microbial mats communities demonstrate very important metabolic and adaptive capacities. Located in the coastal area, these ecosystems may be subject to oil contamination. In this context, the aim of this study is on one hand to describe the structure and functioning of microbial mats and on the other to understand the impact of oil contamination on these ecosystems. This study focused on two microbial mats from the Berre lagoon with close physical chemical parameters but with contrasted hydrocarbon contamination levels. The functioning of the system is dependent on other factors such as light and seasons, diurnal and seasonal variations were taken into account in this study. Special emphasis was placed on the sulfur cycle due to its importance in the marine environments. The results of this study highlighted different communities’ structures at the global level between both mats, the spatial variation prevailed on seasonal variation. The active part of the community from the contaminated site shows a linear trend while that one of the uncontaminated site follows the seasonal variations. The contaminated site shows genes involved in hydrocarbon degradation more expressed coupled to a hydrocarbon biodegradation suggesting that the contaminated mat is adapted to the petroleum contamination. Despite these differences in the structure and the degradation capacities, very similar metabolic profiles are observed between the two mats with similar functions, suggesting functional redundancy. Seasonal and diurnal variation was also observed, the Desulfobulbaceae were particularly more abundant in spring and more active during the day. A complementary cultural approach will allow to better understanding the dynamics of sulfate-Reducers communities in the mat and comprehending these variations
Guilloton, Michel. "Déterminisme génétique et rôle physiologique de la cyanate aminohydrolase chez e. Coli : intéraction spécifique du cyanate avec la biosynthèse de l'arginine." Poitiers, 1987. http://www.theses.fr/1987POIT2010.
Full textSauret-Ignazi, Ginette. "Métabolisme du gai͏̈acol par un moraxella sp : étude d'un nouveau cytochrome P-450 bactérien." Grenoble 1, 1988. http://www.theses.fr/1988GRE10084.
Full textBourdier, Gilles. "Composition biochimique du materiel particulaire lacustre : interets pour l'etude de l'activite metabolique des microorganismes, de la dynamique des populations phytoplanctoniques et des relations trophiques phyto-zooplancton." Clermont-Ferrand 2, 1989. http://www.theses.fr/1989CLF21119.
Full textA, Abdul Malik Shareen. "Defence on surface of Rhodophyta Halymenia floresii : metabolomic profile and interactions with its surface-associated bacteria." Electronic Thesis or Diss., Lorient, 2020. http://www.theses.fr/2020LORIS598.
Full textThe surface of Halymenia floresii, a Mexican Rhodophyta, was observed to be remarkably free of epiphytes under Integrated MultiTrophic Aquaculture (IMTA) conditions. This suggests the presence of allelopathic active compounds released by this macroalgae. The aim of this work was to explore the defence mechanisms developed by H. floresii against surface epibiosis, to detect and identify the secondary metabolites produced at the surface of the algae, and to study its relation with surface associated bacteria. For the first time, we isolated the epibacterial community of H. floresii cultivated under controlled conditions (IMTA) and uncontrolled ones (beach-cast material collected in the area). The isolated epibacteria were screened in vitro to analyse Quorum Sensing (QS) signals, and others H. floresii surface extracts were assayed for any QS interference with them. We differentiated the epibacteria significant pathogens from the non- pathogens ones by their ability to induce bleaching, a well-known algal disease. Vibrio owensii was identified as an opportunistic pathogen inducing bleaching in H. floresii which was also associated to the presence of its C4-HSL QS signal. The surface and whole cell metabolites extracts from H. floresii specimens cultivated under controlled conditions were analysed by means of LC/MS. An untargeted metabolomic analysis of H. floresii was performed to provide a global metabolic profile as a first database. We identified ‘41’ active metabolites in H. floresii, among which halogenated compounds, furanones and various inhibitors were overrepresented. Interestingly, the first two classes are well known potent QS interfering compounds. The relatively higher occurrences of allelopathic metabolites at the surface of H. floresii strongly supports the hypothesis that they must be involved in the host protection. Further investigations are needed to explore the secondary metabolites of H. floresii et their role in the seaweed
Baldet, Pierre. "Quelques observations sur le métabolisme de la biotine chez les plantes supérieures." Grenoble 1, 1993. http://www.theses.fr/1993GRE10054.
Full textLespinat, Paul Antoine. "Métabolisme bactérien de l'hydrogène : aspects physiologiques et enzymologiques." Grenoble 1, 1988. http://www.theses.fr/1988GRE10061.
Full textAl, Mallah Maha. "Biodegradation des hydrocarbures dans les milieux sursales." Aix-Marseille 2, 1988. http://www.theses.fr/1988AIX22040.
Full textHong, Yongsuk. "Effects of surfaces on bacterial metabolic activity: Examination of a physiochemical/bioenergetic mechanism." 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3314503.
Full textMuttray, Annette Friederike. "Population and metabolic activity dynamics of resin-acid-degrading bacteria as determined by the RNA:DNA ratio." Thesis, 2001. http://hdl.handle.net/2429/13117.
Full textFont, Nájera Arnoldo. "Dynamics of occurrence and metabolic activity of microorganisms involved in the removal of nutrients in urban sequential sedimentation-biofiltration systems." Phd diss., 2021. http://hdl.handle.net/11089/39018.
Full textGuateFuturo Foundation, Guatemala, Guatemala city. The scholarship-loan program for young professionals for the specialization in master and doctoral programs abroad (https://guatefuturo.org/). Under the project code: PCB-2017-01. Faculty of Biology and Environmental Protection, University of Lodz. Specialized subsidy for activities related to the conduct of scientific research, development of work, and related tasks for the development of young scientists and participants of doctoral studies under the title of: Dynamika występowania bakterii zaangażowanych w przemiany biogenów w wybranych strefach miejskich systemów sedymentacyjno-biofiltracyjnych. Under the project code: B1711000001531.02. 2017. Faculty of Biology and Environmental Protection, University of Lodz. Specialized subsidy for activities related to the conduct of scientific research, development of work, and related tasks for the development of young scientists and participants of doctoral studies under the title of: Sezonowa i przestrzenna dynamika występowania bakterii zaangażowanych w przemiany biogenów w sekwencyjnych systemach sedymentacyjno-biofiltracyjnych. Under the code: B1811000001811.02. 2018. Faculty of Biology and Environmental Protection, University of Lodz. Specialized subsidy for activities related to the conduct of scientific research, development of work, and related tasks for the development of young scientists and participants of doctoral studies under the title of: Dynamika występowania oraz aktywność metaboliczna mikroorganizmów zaangażowanych w usuwanie biogenów w miejskich sekwencyjnych systemach sedymentacyjno-biofiltracyjnych. Under the code: B1911000002130.03. 2019. Cooperation with the European Regional Centre for Ecohydrology of the Polish Academy of Sciences (ERCE PAS)
Yamashita, M., M. Shepherd, W. I. Booth, H. Xie, V. Postis, Yvonne Nyathi, S. B. Tzokov, R. K. Poole, S. A. Baldwin, and P. A. Bullough. "Structure and function of the bacterial heterodimeric ABC transporter CydDC: stimulation of ATPase activity by thiol and heme compounds." 2014. http://hdl.handle.net/10454/17911.
Full textIn Escherichia coli, the biogenesis of both cytochrome bd-type quinol oxidases and periplasmic cytochromes requires the ATP-binding cassette-type cysteine/GSH transporter, CydDC. Recombinant CydDC was purified as a heterodimer and found to be an active ATPase both in soluble form with detergent and when reconstituted into a lipid environment. Two-dimensional crystals of CydDC were analyzed by electron cryomicroscopy, and the protein was shown to be made up of two non-identical domains corresponding to the putative CydD and CydC subunits, with dimensions characteristic of other ATP-binding cassette transporters. CydDC binds heme b. Detergent-solubilized CydDC appears to adopt at least two structural states, each associated with a characteristic level of bound heme. The purified protein in detergent showed a weak basal ATPase activity (approximately 100 nmol Pi/min/mg) that was stimulated ∼3-fold by various thiol compounds, suggesting that CydDC could act as a thiol transporter. The presence of heme (either intrinsic or added in the form of hemin) led to a further enhancement of thiol-stimulated ATPase activity, although a large excess of heme inhibited activity. Similar responses of the ATPase activity were observed with CydDC reconstituted into E. coli lipids. These results suggest that heme may have a regulatory role in CydDC-mediated transmembrane thiol transport.
This work was supported by Biotechnology and Biological Sciences Research Council grant BBS/B/14418 (Membrane Protein Structure Initiative).
Grater, Elizabeth Mathilde. "Le périple du métabolisme bactérien à travers le paysage fluvial du Saint-Laurent = A bacterial metabolic journey through the St. Lawrence riverscape." Thèse, 2020. http://depot-e.uqtr.ca/id/eprint/9729/1/eprint9729.pdf.
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