Dissertations / Theses on the topic 'Biological importance'
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1
Jiang, Lu. "Chemical synthesis of peptides with biological importance." Thesis, University of Edinburgh, 1996. http://hdl.handle.net/1842/12302.
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Gilchrist, Peter James. "Crystallographic studies on molecules of biological importance." Thesis, University of Edinburgh, 1993. http://hdl.handle.net/1842/19791.
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This thesis describes crystallographic investigations into the structures of a number of biological macromolecules. The purpose of these investigations has been to provide an understanding of the structural basis of their biological activities and their interactions with other macromolecules. The first chapter provides a general introduction to this study and, in particular, to the two proteins that were investigated - equine phospholipase A2 and salmon calcitonin. Chapter two provides some general theory into the methods of x-ray crystallography and its application to the solution of the structure of an agonist to 5-HT1A receptors. Chapter three outlines the bulk purification of another phospholipase A2 from sheep pancreas for crystallographic study. Chapter four outlines the theory and methodology of protein crystallisation as applied to the attempted crystallisation of salmon calcitonin and two derivatives thereof. The crystallisation of a supposed phospholipase A2 inhibitor complex is also reported. Chapter five outlines the process of x-ray structure refinement as applied to equine phospholipase A2 using two refinement packages XPLOR and TNT. The refinement of the proposed enzyme inhibitor complex is also reported. Chapter 6 outlines the three dimensional structure of equine phospholipase A2 and compares and contrasts this structure with a previously determined phospholipase S2 structure. The last chapter, chapter seven, concludes on the results of the various investigations, correlating structure with biological activity.
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Davis, A. M. "A kinetic investigation of reactions of biological importance." Thesis, University of Huddersfield, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376448.
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Lojek, Lisa Jeanne. "Defining the Biological Importance and Conservation of Heme Degrading Enzymes." Thesis, Vanderbilt University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13877288.
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Edetanlen-Elliot, O. "Vinyl sulfonates : a platform for novel substrates of biological importance." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1301991/.
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Sulfonamides constitute a vital and diverse class of therapeutic agents. Their means of synthesis has often involved the use of unstable sulfonyl chloride species; however, recent research has established pentafluorophenyl (PFP) and trichlorophenyl (TCP) sulfonate esters as a useful stable alternative to such species. This thesis describes an exploration into the reactivity of the bifunctional acceptors pentafluorophenyl vinyl sulfonate and trichlorophenyl vinyl sulfonate. Intermolecular alkyl radical addition to trichlorophenol vinyl sulfonate mediated by both 1-ethylpiperidinium phosphate (EPHP) and tributyltin hydride was carried out effectively to generate a library of alkyl sulfonates. Notably, this was extended to the synthesis of a bifunctional alkyl PFP/TCP sulfonate via a double radical addition protocol which was envisaged could be useful in determining the reactivity between PFP and TCP. 1,3-Dipolar cycloaddition reactions were carried out effectively at the electron-deficient olefinic portion of the vinylsulfonates to provide functionalized sulfonate esters with excellent regioselectivity. Addition of an α and a β substituent to vinylic portion of PFP and TCP vinyl sulfonate changed the electronics and sterics of the sulfonates, however functionalised esters with great regioselectivity could still be synthesised.
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Wade, Vanessa J. "The biomineralization of ferritin and haemosiderin." Thesis, University of Bath, 1991. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303553.
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Li, Hong-Qiang. "Adsorption of molecules of biological importance at the gold-solution interface." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ56285.pdf.
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McKerrecher, Darren. "Synthetic approaches to diene- and enyne-containing natural products of biological importance." Thesis, University of York, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242186.
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Bonnas, Christel [Verfasser]. "Identification of erythropoietin isoforms and evaluation of their biological importance / Christel Bonnas." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2009. http://d-nb.info/1023581590/34.
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Packer, Kirsten F. "Evaluating the importance of root abscission versus efflux to plant N-loss: consequences for plant N-isotope composition." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/28152.
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The common observation that plant δ¹⁵N values are lower than those of associated soil is generally attributed to transporter-facilitated efflux of ¹⁵N-enriched N. N efflux tends to occur under specific conditions, for instance, when the external N concentration is high, when the external medium is acidic and when roots experience mechanical stress. While efflux is presumed to act as a regulator of cytoplasmic N concentrations, it is energetically costly for plants to take up N only to release it back into the rhizosphere. A link between root tissue loss (e.g. root turnover or rhizodeposition) and plant δ¹⁵N has not been suggested, although root abscission is likely to be more ubiquitous than N efflux. This thesis questions the extent to which N efflux and root abscission contribute to plant N-loss and plant δ¹⁵N values. I hypothesized that: (1) plants supplied with more N would have more negative δ¹⁵N relative to the source, and greater root abscission from a relatively larger root biomass (2) the aeration necessary for hydroponic culture can act as a mechanical stressor on roots, accentuating plant N-loss through root abscission and N efflux. Wheat was grown in sand with NO₃- supplied at five relative addition rates (RAR) and in hydroponics with three physical disturbance regimes (direct aeration, aeration constrained within a pipe and circulation of nutrient solution through sand). The δ¹⁵N of roots and shoots, as well as the plant-derived N accumulation in both growth mediums, were determined. When the N supply matched the plant N demand, as determined by the relative growth rate, there was no discrimination between plant and source δ¹⁵N. N-loss here, although negligible, was in the organic form, which implies root abscission. By contrast, when N supply exceeded plant N demand, plant δ¹⁵N values decreased (e.g. after 47 d, plant δ¹⁵N of RAR 0.075 d⁻¹ was 0.4‰ but was −4.1‰ at RAR 0.175 d⁻¹) because they lost ¹⁵N-enriched N. This N was largely inorganic and presumably lost through efflux. In disturbed hydroponic conditions (i.e. direct and pipe treatments), root 'fragments' were a major biomass- (six-fold greater than root dry weight) and N-loss (two-fold greater than plant net N uptake) pathway. Plants from all treatments lost more N within root fragments than through efflux, although the cumulative N-loss was significantly smaller from plants grown in relatively undisturbed hydroponic conditions (i.e. sand). This suggests that root abscission is likely to be an important N-loss pathway for plants and thus contributes to the global offset between plant and soil δ¹⁵N values. Moreover, efforts to improve nitrogen use efficiency of crop plants, though reduced efflux, need to take cognizance of root abscission because it is an unavoidable artefact of root growth.
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Tavares, Joana Flor R. "Assessing the importance of biological uncertainties to the control of species introductions via ballast water /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 90 p, 2009. http://proquest.umi.com/pqdweb?did=1654487631&sid=3&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Idowu, Mopelola Abidemi. "Photophysical and photochemical behaviour of metallophthalocyanines effect of nanoparticles and molecules of biological importance." Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1004990.
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Syntheses, spectral, photophysical and photochemical studies of some neutral, anionic and cationic metallophthalocyanine derivatives are presented. The effects of central metal ions, solvents, aggregation, surfactant, nanoparticles and bovine serum albumin on the photophysical and photochemical behaviour are investigated. Mercaptocarboxylic acid stabilized CdTe quantum dots (QDs) were used as energy donors to anionic water-soluble MPcs through Förster resonance energy transfer (FRET). Energy transfer (ET) from the QDs to the MPcs occurred upon photoexcitation of the QDs. An enhancement in efficiency of ET with the nature of the cappings on the QDs was observed with few occurrences of a non-Förster type ET. QDs were found to improve the photophysicochemical behaviour of the MPcs, with the possibility of indirect production of singlet oxygen (Φ[subscript Δ]) via FRET mechanism. Interaction of the QDs with cationic water-souble MPcs produced ion-pair complexes resulting in aggregates due to strong electronic coupling. The stoichiometry of the reaction and association constants are evaluated by the continuous variation method. Improved photophysicochemical behaviour with no spectral alterations was observed in MPcs in the presence of magnetic fluid. Complexes showed high triplet quantum yields with corresponding long lifetimes and high photostability. Elucidation of the results of the interaction of bovine serum albumin (BSA) with MPcs or QDs is presented. Increased efficiency of Φ[subscript Δ] generation of MPcs in the presence of BSA coupled with large binding constants, suggesting strong interaction of the MPcs with BSA was observed. Enhanced emission intensity of QDs when linked to or in a mixture with BSA due to radiationless recombination at the surface vacancies was also observed. The study revealed positive deviation from Stern-Volmer relationship suggesting the occurrence of static and dynamic mechanisms of quenching together. Fluorescence quenching of the MPcs by benzoquinone, analysed by Stern-Volmer relationship is also presented; the results were employed in determining fluorescence lifetimes of the complexes. Photoelectrochemical characteristics of MPc-sensitized electrodeposited ZnO thin films were studied; ZnOCPc / ZnO films have been improved to an incident photon-to-currentconversion (IPCE) value of 31.1 % with an absorbed photon-to-current conversion (APCE) of 59.6 %. The best obtained so far with phthalocyanine-type sensitizers on nanocrystalline ZnO films. Fluorescent-magnetic nanocomposite with excellent photophysical properties which can be exploited for combined photodynamic and hyperthermia therapies is also presented.
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Gall, Margaret Gaye. "Investigating the biological importance of Dipeptidyl Peptidase 9 enzymatic activity using a mouse model." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16836.
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Dipeptidyl peptidase 9 (DPP9) is an atypical post-proline serine protease of the DPP4 enzyme family which has ubiquitous expression and DPP4-like enzymatic activity. It is localised intracellularly and has roles in antigen processing and epidermal growth factor signalling. It interacts with H-Ras and small ubiquitin-like modifier-1 and influences cellular interactions with extracellular matrix. Our lab made the first DDP9 gene knock-in (gki) mouse with a DPP9 active site (S729A) mutation which results in a lack of DPP9 enzymatic activity. This thesis investigated the biological properties of DPP9 using this genetically modified mouse model. Mice lacking DPP9 proteolytic activity die in the early neonatal stage. This study validated that the DPP9 protein, while present in the gki mouse, is enzyme-inactive and the DPP9-S729A protein and wild-type DPP9 have similar subcellular localisation. A range of investigations were undertaken to determine if obvious histological and/or physiological differences exist between early neonate DPP9S729A/S729A homozygotes from their heterozygous and wild-type littermates and involved analysis of organ morphology, histology and function and investigation of autophagy. The novel findings of this study show that DPP9 enzymatic activity is essential for early neonatal survival in mice and suggest that there is dysregulated autophagy in the DPP9-enzyme-activity-deficient neonatal mice that may contribute to the lethal phenotype. Other members of the DPP4 protein family are implicated in wound healing with fibroblast activation protein expressed in the granulation tissue of healing wounds and DPP4-positive T cells involved in regulation of granulation tissue formation. As there is a heterozygous effect on survival to weaning and DPP9 immunoreactivity was shown in the skin of both WT and DPP9S729A/S729A neonates, the skin of adult mice was studied using a model of cutaneous wound healing. This involved analysis of wound closure rates, tensile strength and collagen levels of both wounded and steady state tissue in adult DPP9wt/S729A mice and their wild-type littermates. It was found that adult heterozygous DPP9-GKI mice display reduced skin collagen levels compared to their WT littermates, but that the rate of skin wound healing appeared unaffected. DPP9 has in vivo expression in normal immunological tissues and major lymphocyte populations that alters with chronic liver injury, suggesting a role in immune function. To investigate the importance of DPP9 in immune regeneration and function, primary and secondary mixed chimeric mice were created using DPP9S729A/S729A and WT fetal liver cells and adult bone marrow, respectively, injected into irradiated recipients. The process of regeneration of the immune system in these mice was assessed at several time-points and the immune cells present in the regenerated immune systems were compared between DPP9S729A/S729A-origin and WT-origin chimeras. These chimeric mice were then subjected to an immune challenge by influenza virus infection. The novel findings of this study suggest that DPP9-enzyme-activity-deficient secondary chimeric mice may have an enhanced ability to recover from an immune challenge with influenza virus. Therefore, DPP9 appears to influence immune function in that viral infection. Together, these studies underline the biological significance of DPP9 in vivo in both neonatal and adult mice. These data contribute to the expanding knowledge of the role of DPP9, building upon recent discoveries in vitro of its involvement in multiple biological processes. By providing physiologically relevant results, this study has enhanced the knowledge of DPP9 enzyme function and the overall biological roles of DPP9.
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Holloway, Andrew Charles. "Antimicrobial effects of white tea extracts in combination with putative adjuncts against 'Staphylococcus aureus' and other microbes of importance." Thesis, Kingston University, 2013. http://eprints.kingston.ac.uk/28229/.
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Previous studies have investigated biological activities of plant extracts and their subcomponent compounds as antimicrobial treatments. The addition of adjunct substances in varying combinations to such agents has also been shown to enhance their antimicrobial activities - a desirable outcome in the development of novel treatment substances to combat pathogens. Whole extracts of tea leaves processed in different ways to produce black, green and white tea types (BT, GT, WT) show different activities. In addition, the effects on pathogens of highly active GT extract rich in flavan-3-ols which are catechins have also been investigated alone and with additives and these can compare favourably with the activities of conventional antibiotics such as oxacillin and ciprofloxacin. However, relatively little attention has been paid to enhancing the activity of whole WT or its weak antimicrobial subcomponents. The activities of GT and BT were compared to the less researched white tea (WT). Principal tea flavan-3-ols were also screened for activity alone, and combined with a known antimicrobial agent copper(II)sulphate against 'Staphylococcus aureus' NCTC 06751. WT, a sub-fraction, (WTF
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Ritt, Marie-Claude. "Thermodynamics of interaction of macrocyclic ligands with multivalent ions and organic molecules of biological importance." Thesis, University of Surrey, 1991. http://epubs.surrey.ac.uk/843105/.
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The first part of this work deals with the determination of the thermodynamic parameters for the complexation of lanthanide cations (La3+, Pr3+ and Nd3+) with Cryptand-221 and Cryptand-222 in acetonitrile and propylene carbonate at 298.15 K. The complexation process between these cations and these ligands in these solvents is enthalpy-controlled. The higher stability observed for these cations and these ligands in propylene carbonate with respect to acetonitrile is attributed to the increase in entropy observed for the complexation reaction in propylene carbonate. Enthalpies of solution of lanthanide and lanthanide cryptates are reported. These data are used to derive single-ion enthalpies of transfer of La3+, Pr3+ and Nd3+ from propylene carbonate to acetonitrile based on the Ph4AsPh4B convention. The results show that the cryptate conventions are not valid for the calculation of single-ion values for the transfer of tervalent lanthanide cations among dipolar aprotic media. Enthalpies of coordination of lanthanide(III) cryptates in the solid state are calculated. The second part of this study aims to investigate the properties of the synthetic macrocyclic ligands such as Cryptand-222 and 18-Crown-6 towards molecules of biological importance. Stability constants (hence free energies), enthalpies and entropies of complexation of a series of DL-amino acids with 18-Crown-6 and Cryptand-222 in methanol and ethanol, as obtained from titration calorimetry, are reported. No significant variations are found in the free energies of complexation of the different amino acids and these two ligands in these solvents as a result of an enthalpy-entropy compensation effect. This effect is for the first time shown in complexation reactions involving crown ethers and cryptands. The thermodynamic parameters of transfer of amino acids and their complexes with 18-Crown-6 and Cryptand-222 from methanol to ethanol have been calculated. Possible correlations between complexation and transfer data for the amino acids, the ligands and the amino acid-macrocyclic ligand complexes are investigated. The implications of these results to processes of biological importance are discussed. As a continuation of this study, the possibility of selectively extracting amino acids from methanol by polymeric resins containing crown ethers as anchor groups is investigated.
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Yin, Nang Htay. "Weathering of metallurgical slags : a comprehensive study on the importance of chemical and biological contributions." Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1125/document.
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Le crassier du site MetalEurop (Noyelles-Godault) a accueilli des scories de première fusion entre les années 1936 à 2003. Il est actuellement constitué de 4 millions de tonnes de ces matériaux générés par les deux procédés pyrométallurgiques les plus usités dans le monde pour la production du plomb et du zinc : le procédé Lead Blast Furnace (LBF) et le procédé Impérial Smelting Furnace (ISF). L'utilisation de ces scories en tant que matériau de substitution dans les ciments et dans les routes a été envisagée et a fait l'objet de recherches, mais présente des risques environnementaux, c'est-à-dire, essentiellement la dissémination de polluants (Pb et Zn)Primary smelting slags, known as Lead Blast Furnace (LBF) and Imperial Smelting Furnace (ISF), were generated by the former pyrometallurgical industries located in Noyelles-Godault, Northern France. Following its closure in 2003, 4 million tons of primary slags have been landfilled as a heap in the vicinity of the Deûle River, near the industrial basin of Nord-Pas-de-Calais. These slag materials are often enriched in particular metals (Pb, Zn) that can be released into the environment through alteration processes and leaching. Many biological and chemical processes might take place within these tailings and thus affect significantly the slag weathering. Predicting the environmental impact of these wastes requires an understanding of the mineral-water interactions as well as the influence of the biological activities (the involvement of microorganisms). Thus, this research is designed to simulate the natural weathering of slag by simulating different weathering conditions with or without the involvement of the microorganisms as well as by varying several chemical parameters. Chemical weathering of both LBF and ISF slags was studied by as a function of pHs (4, 5.5, 7, 8.5 and 10) as well as under two atmospheres (open air and nitrogen). Significant amounts of Ca, Fe and Zn were released under acidic conditions (pH 4) with a decrease towards the neutral to alkaline conditions (pH 7 and 10) for both slags. The concentrations of all elements increased gradually after 216 h compared to initial 24 h of leaching period. The presence of oxygen under open-air atmosphere not only enhanced oxidative weathering but also encouraged formation of secondary oxide and carbonate phases. In addition, Zn dissolution was related to extremes zinc isotopic signatures in the leachate; heavier δ66Zn values at low pH than at high pH for both slags under open-air atmosphere. On the other hand, bioweathering of both slags was studied in the presence of a pure heterotrophic bacterial strain (Pseudomonas aeruginosa) in a bioreactor operated in batch conditon as well as in a semi-flow through reactor with intermittent leachate renewal conditions. P. aeruginosa is shown to play a significant role in slags weathering by enhancing the leaching and solubility of Zn and Pb. In addition, the cumulative bulk release of dissolved Fe, Si, Ca and Mg doubled in the presence of bacteria, probably due to the release of soluble complexing organic molecules (e.g. siderophores). Bacterial biomass served as the bioadsorbent for Pb, Fe and Zn as 70-80% of Pb and Fe, 40-60% of Zn released are attached to and immobilized by the bacterial biomass. Oxides, hydroxides and carbonates were predicted as secondary phases during chemical weathering of slags whereas carbonates and phosphates were dominant phases during bioweathering. These predictions were in agreement with the observations by Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDS), Transmission Electron Microscopy (TEM) analysis, and X-ray Photoelectron Spectroscopy (XPS) analysis
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Bush, Hannah Dawn. "Investigation into the reactivity of pentafluorophenyl vinylsulfonate in the formation of functionalized sulfonamides of biological importance." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1444387/.
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Sulfonamides constitute a vital and diverse class of therapeutic agents hence the development of convenient and straightforward synthetic routes to such species is a valuable endeavour. This thesis describes an exploration into the reactivity of the novel bifunctional acceptor pentafluorophenyl vinylsulfonate in the formation of biologically interesting sulfonamide species. A variety of transformations were carried out effectively at the electron-deficient olefinic portion of pentafluorophenyl vinylsulfonate to provide functionalized pentafluorophenyl esters. Subsequent displacement of the pentafluorophenyl moiety via an established aminolysis procedure then delivered the corresponding sulfonamide products. During the course of this investigation, it was established that both radical and cycloaddition routes were successful in furnishing desirable compounds. It was found that intermolecular radical addition of alkyl halides occurred readily and permitted the formation of a number of sulfonamide addition products. In addition, Diels-Alder cycloaddition with carbocyclic dienes and furan formed stable exo-bicyclic sulfonamides. Notably, 1,3-dipolar cycloaddition with a diverse library of A/-methyl-nitrones gave the corresponding isoxazolidine species with unprecedented regio- and stereoselectivity. Subsequent aminolysis delivered functionalized heterocyclic sulfonamides with potential biological importance.
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Paci, Donatella. "A theoretical method for electronic structure calculations on systems of biological importance : the group function approach." Thesis, University of St Andrews, 1994. http://hdl.handle.net/10023/15439.
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Theoretical methods for studying molecules of biological importance are reviewed, both ab initio and semi-empirical. The Group Function Approach is developed in detail in its strong orthogonal form and corrections to the energy are added for taking into account non-orthogonality effects, depending on the overlaps of the group functions. Approximations are introduced and tested so that this method can be applied to large molecules. In particular, a system (or a relevant fragment of it) is built up from localized two-electron groups, each one described by a two-electron group function (geminal). Each group function is optimized by using an SCF method with an effective hamiltonian consisting of the two-electron hamiltonian of the group together with the effective potential due to the presence of the other electron groups (and to the external environment, eventually). The wavefunction for the whole molecule is an antisymmetrized product of geminals. The energy is computed as a sum of group contributions. Corrections, depending on up to the second power of the overlaps of two groups at a time, are particularly important in conformational studies. The approximations introduced are based on the consideration that distant groups consisting of two positive and two negative charges see each other as neutral entities and thus do not contribute appreciably in the definition of the effective hamiltonian: the computing effort is greatly reduced in this way, the error introduced is small and can be estimated easily. The theoretical method presented in this thesis offers a powerful tool for making qualitative predictions of the changes resulting from localized effects, such as twisting around a bond, and it can be usefully applied to conformational studies and geometry optimizations. The other properties which can be calculated axe for the most part directly related to the electron density; this determines, for example, the electrostatic potential outside a molecule and hence the position of attack by approaching ions or polar species. Chemical reactions, which involve breaking or re-arrangement of bonds, provide another vast field of application. Such processes usually involve only localized regions in a molecule and the admission of intragroup CI ensures that the study of bond breaking remains valid throughout the whole process. All necessary computer programmes have been developed and numerical applications have been made to a range of molecules, including hydrocarbons, small molecules containing double bonds and lone pairs, and the amino acid glycine.
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Jin, Ying. "New Algorithms for Mining Network Datasets: Applications to Phenotype and Pathway Modeling." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/40493.
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Biological network data is plentiful with practically every experimental methodology giving â network
viewsâ into cellular function and behavior. Bioinformatic screens that yield network data
include, for example, genome-wide deletion screens, protein-protein interaction assays, RNA interference
experiments, and methods to probe metabolic pathways. Efficient and comprehensive
computational approaches are required to model these screens and gain insight into the nature of biological
networks. This thesis presents three new algorithms to model and mine network datasets.
First, we present an algorithm that models genome-wide perturbation screens by deriving relations
between phenotypes and subsequently using these relations in a local manner to derive genephenotype
relationships. We show how this algorithm outperforms all previously described algorithms
for gene-phenotype modeling. We also present theoretical insight into the convergence and
accuracy properties of this approach. Second, we define a new data mining problemâ constrained
minimal separator miningâ and propose algorithms as well as applications to modeling gene perturbation
screens by viewing the perturbed genes as a graph separator. Both of these data mining
applications are evaluated on network datasets from S. cerevisiae and C. elegans. Finally, we
present an approach to model the relationship between metabolic pathways and operon structure in
prokaryotic genomes. In this approach, we present a new pattern classâ biclusters over domains
with supplied partial ordersâ and present algorithms for systematically detecting such biclusters.
Together, our data mining algorithms provide a comprehensive arsenal of techniques for modeling
gene perturbation screens and metabolic pathways.Ph. D.
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Baker, Sarah. "A biocultural analysis of natural mummification : the importance of preservation on the examination of biological and cultural evidence." Honors in the Major Thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1060.
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This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Sciences
Anthropology
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Mattsson, Emma. "Importance of Fucus vesiculosus (bladderwrack) for coastal fish communities in the Baltic Sea." Thesis, Stockholms universitet, Institutionen för ekologi, miljö och botanik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-176300.
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Within temperate coastal seascapes, macroalgae provide habitats for different organisms such as invertebrates and fish. In analogy to seagrass meadows, macroalgae beds are known for their importance as fish nurseries. However, within the Baltic Sea the importance of the canopy forming macroalgae Fucus vesiculosus for coastal fish communities, especially the juveniles, is unclear. In order to address this knowledge gap, fish communities in areas with and without F. vesiculosus were investigated around Askö, an island in the archipelago of the Baltic Sea. Sites were subjected to different exposures (sheltered, exposed or very exposed) and three different methods were used for sampling (underwater visual census (UVCs), beach seine netting and remote underwater videos (RUVs)). Overall, fish community composition differed significantly among locations and fish abundance and fish biomass were significantly higher in sites with F. vesiculosus than sites without. There was no significant relationship between algae cover or habitat complexity and fish abundance/biomass in sites with F. vesiculosus. Fish behaviour differed between sites with and without F. vesiculosus, with fish feeding more in sites with F. vesiculosus and traveling more in sites without F. vesiculosus. Only one location, Knabberskär, had significantly higher species richness in F. vesiculosus than in sites without F. vesiculosus. There were no differences in juvenile abundance among sites with or without F. vesiculosus and abundance of adult fish was higher than juvenile fish, regardless of location, site or species. Mean invertebrate abundance was a twice as high in the sheltered location Husbåtsviken than in Knabberskär. Higher fish abundance, fish biomass and species richness in sites with F. vesiculosus compared to sites without, suggest that macroalgae may play an important role in the Baltic Sea, however it might not be as important for juvenile fishes as predicted. The three different sampling methods provided similar results for fish abundance, but not for fish biomass. Continued studies where the relationship between fish communities and aspects of F. vesiculosus structure (such as canopy height) as well as linkage with other habitats is recommended for further understanding and better protection of F. vesiculosus habitats.
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Wedel, Elsa. "Ecosystem Services as a Pedagogical Perspective for Teaching the Importance of Biodiversity to High School Students." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-148588.
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Reducing the rate at which biodiversity is presently being lost is one of the challenges for the coming years. Through diverse activities, humankind is currently responsible for the extinction of species worldwide, which has consequences for whole ecosystems. The preservation of biodiversity is not only important for its intrinsic values, but also for its role in maintaining the functioning of ecosystems that provide humans with services that are important for our well-being and safety. As it is a concern for all of humanity there is a demand for education that can develop in students an understanding of the complexity which lies behind the ecosystem services of which they benefit. Including how the disturbance of this complexity will lead to consequences for the whole human world. Current attempts to educate the public has failed to conjure motivation and interest. However, ecological network research create opportunity for understanding the underlying relationships between species, and the use of ecosystem services as a pedagogical perspective offers the possibility to demonstrate the importance of these relationships for ecosystem functioning. In this literature review it is examined how this could benefit environmental education in high school.
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Verschuyl, Jacob Pieter. "Biodiversity potential in the Pacific and Inland Northwest the relative importance of forest structure and available energy in driving species diversity /." Diss., Montana State University, 2007. http://etd.lib.montana.edu/etd/2007/verschuyl/VerschuylJ0507.pdf.
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Rudberg, Krista N. "THE IMPORTANCE OF SEROTONERGIC AND ADRENERGIC RECEPTORS FOR THE INDUCTION AND EXPRESSION OF ONE-TRIAL COCAINE-INDUCED BEHAVIORAL SENSITIZATION." CSUSB ScholarWorks, 2016. https://scholarworks.lib.csusb.edu/etd/420.
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Addiction is a complex process in which behavioral sensitization may be an important component. While the behavioral effects of sensitization are well established, the intricate neurobiology of the phenomenon is still largely unknown. Dopamine systems mediate the induction of behavioral sensitization in adult rats, but there is a large amount of evidence showing that other neurotransmitter systems also modulate the induction process. For example, the α1b-adrenergic and 5-HT2A receptor systems are known to modulate the sensitized responding of adult rats, but the roles that these receptor systems play in the induction and expression of behavioral sensitization during the preweanling period has yet to be investigated. Therefore, the purpose of this thesis was to determine whether the serotonergic and adrenergic receptor systems mediate the induction and/or expression of cocaine-induced one-trial behavioral sensitization in preweanling rats. I used a novel approach to address this question, as the receptors of interest were “protected” from the alkylating effects of EEDQ (an irreversible nonselective receptor antagonist) by prior treatment with selective antagonist drugs. More specifically, rats were given ritanserin (a serotonergic receptor antagonist), prazosin (an adrenergic receptor antagonist), or a combination of the two drugs prior to an injection of EEDQ. To study the induction of behavioral sensitization, this series of injections was administered on PD 18 (24 h before the pretreatment injection of cocaine). To study the expression of behavioral sensitization, the injections were administered on PD 20, which was the day between the drug pretreatment day and the test day. In all experiments, the test day (i.e., the day on which the challenge dose of cocaine was given) was on PD 21. Control experiments were performed for both the induction and expression paradigms in order to determine whether prazosin and ritanserin independently affected sensitization. Results showed that the receptor inactivation caused by EEDQ blocked both the induction and expression of cocaine-induced one-trial behavioral sensitization. Importantly, administering prazosin and ritanserin did not protect the induction of the sensitized locomotor response, which suggests that serotonergic and adrenergic receptors do not mediate cocaine-induced one-trial behavioral sensitization in preweanling rats. This conclusion should be tempered, however, because co-administration of prazosin and ritanserin affected the locomotor activity and sensitized responding of cocaine-treated rats independent of the actions of EEDQ. Considering both past and present results, the most harmonious conclusion is that multiple receptor systems (i.e., dopaminergic, serotonergic, adrenergic, etc.) work in unison to produce the complex phenomenon of behavioral sensitization.
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Salgado, J. B. "The relative importance of eutrophication and connectivity in structuring biological communities of the Upper Lough Erne system, Northern Ireland." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1348584/.
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This study investigates the relative importance of eutrophication and connectivity (dispersal) in structuring macrophyte and invertebrate lake assemblages across spatial and temporal scales in the Upper Lough Erne (ULE) system, Northern Ireland. Riverine systems and their associated flood-plains and lakes comprise dynamic diverse landscapes in which water flow plays a key role in affecting connectivity. However, as for many other freshwater systems, their ecological integrity is threatened by eutrophication and hydrological alteration. Eutrophication results in a shift from primarily benthic to primarily pelagic primary production and reductions in species diversity, while flow regulation often reduces water level fluctuation and hydrological connectivity in linked riverine systems. Low water levels promote isolation between areas and increases the importance of local driving forces (e.g. eutrophication). Conversely, enhanced water flow and flooding events promote connectivity in systems thus potentially increasing local diversity and homogenising habitats through the exchange of species. Therefore, connectivity may help to override the local effects of eutrophication. Attempts at testing the above ideas are rare and typically involve the examination of current community patterns using space for time substitution. However, biological community responses to eutrophication and changes in hydrological connectivity may involve lags, historical contingency, and may be manifested over intergenerational timescales (10s -100s of years), rendering modern studies less than satisfactory for building an understanding of processes that drive community structure and effect change. By combining contemporary and palaeolimnological data this study demonstrates that the ULE system is far from its pre-disturbance state as an oligotrophic-mesotrophic system. Furthermore, contemporary and palaeo-data suggest there has been a strong interaction between eutrophication and hydrological change, which influences the distributions and abundances of representative taxa in the ULE system. Thus, while eutrophication has promoted a decrease in compositional heterogeneity of organisms and has exerted a homogenising effect over time, connectivity has buffered the effects of eutrophication helping to maintain local diversity via re-introductions.
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Schmaljohann, Heiko. "The relative importance and biological significance of non-stop and intermittent flight strategies in bird migrants crossing the Sahara /." Basel : [s.n.], 2007. http://edoc.unibas.ch/diss/DissB_7986.
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Mohd-Yusof, Martha A. "IMPORTANCE OF THE D2 RECEPTOR FOR ONE- AND MULTI-TRIAL PSYCHOSTIMULANT-INDUCED BEHAVIORAL SENSITIZATION IN PREWEANLING RATS." CSUSB ScholarWorks, 2016. https://scholarworks.lib.csusb.edu/etd/349.
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The neural mechanisms mediating one-trial and multi-trial behavioral sensitization during early ontogeny are poorly understood. The purpose of this thesis was to assess the importance of D2-like receptors for the induction of cocaine- and methamphetamine-induced one-trial and multi-trial behavioral sensitization during the middle and late preweanling period. In a series of four experiments, rats were injected with saline or the selective dopamine D2-like receptor antagonist raclopride 15 min prior to treatment with the indirect dopamine agonists cocaine or methamphetamine. Acute control groups received two injections of saline. The pretreatment regimens occurred on either PND 16 or PND 20 (one-trial behavioral sensitization) or PND 13-16 or PND 17-20 (multi-trial behavioral sensitization). On PND 17 or PND 21, rats were challenged with either cocaine or methamphetamine and sensitized responding was assessed. With only a single exception, both one -trial and multi-trial cocaine- and methamphetamine-induced sensitization was evident on PND 17 and PND 21. Importantly, the D2-like receptor antagonist raclopride did not prevent the induction of cocaine- or methamphetamine-induced one-trial behavioral sensitization. In regards to multi-trial behavioral sensitization, raclopride failed to inhibit cocaine -induced sensitized responding on PND 17 and PND 21. Interestingly, higher doses of raclopride (0.5 and 1 mg/kg) were able to prevent the induction of multi-trial methamphetamine-induced sensitization on PND 17. Therefore, D2-like receptor antagonism differentially affected methamphetamine -induced behavioral sensitization depending on whether a one-trial or multi-trial paradigm was employed. When considered together, these results suggest that the neural mechanisms underlying the methamphetamine -induced behavioral sensitization of preweanling rats differs depending on the type of experimental paradigm (one- vs multi-trial) being used. Other potential explanations (i.e., nonspecific antagonist effects, impact of contextual conditioning, etc.) for this interesting effect are presented in the Discussion.
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Gredmark, Sara. "Biological importance of cytomegalovirus infection in health and disease : profound effects of infection on monocyte and smooth muscle cell function /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-213-6/.
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Novossiolova, Tatyana, Simon M. Whitby, Malcolm R. Dando, and Graham S. Pearson. "Strengthening the Biological and Toxin Weapons Convention: The vital importance of a web of prevention for effective biosafety and biosecurity in the 21st Century." Biological Weapons Convention, 2019. http://hdl.handle.net/10454/17580.
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Hinsberger, Aurélie. "Structuration des populations virales chez les baculovirus. Importance de l'infection multiple." Thesis, IMT Mines Alès, 2020. http://www.theses.fr/2020EMAL0005.
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La gestion des ravageurs des cultures a été de tout temps un enjeu d’importance. Dans l’agriculture moderne, cette gestion passe en particulier par l’utilisation d’insecticides de plus en plus respectueux de l’environnement et de la santé. Dans la lutte contre le ravageur du pommier Cydia pomonella, les bioinsecticides à base du baculovirus CpGV sont utilisés en Europe depuis presque 30 ans. Cependant, l’utilisation massive d’un seul génotype viral a conduit à l’apparition, et la dispersion, d’insectes résistants, compromettant les productions fruitières. Il a été montré que la diversité génétique des baculovirus persiste dans les populations d’insectes résistants, même les génotypes contre lesquels des résistances spécifiques ont été développées. L’utilisation de cette diversité en lutte biologique, en particulier l’obtention d’une infection multiple dans chaque insecte, représente une solution pour limiter l’apparition de résistance chez l’insecte.L’objectif de ces travaux de recherche est de garantir une gestion durable des résistances, en explorant les avantages de la diversité génétique virale et des infections multiples pour une utilisation agronomique. Ce travail comporte deux parties, l’une portant sur le développement et l’autre sur l’utilisation de méthodes d’exploration des infections en conditions de terrain et de laboratoire. Deux outils permettant le suivi des génotypes de CpGV à différentes échelles ont été développés. Le premier outil est l’adaptation de la technologie ANCHORTM aux baculovirus, en les rendant autofluorescents, cette technique permet de suivre chaque génotype à l’intérieur d’une cellule. Le deuxième outil est l’utilisation des différences de température de fusion de fragments spécifiques de leurs génomes (HRM), ici le fragment différentiel du gène pe38 a été utilisé. Cet outil permet de quantifier la fréquence des génotypes CpGV-M et CpGV-R5 dans un insecte infecté, et d’analyser un grand nombre d’échantillons, donc d’établir la prévalence de ces génotypes dans une population. Ces outils ont été mis en application sur le terrain et en laboratoire afin d’évaluer la dynamique des infections multiples. L’étude des interactions entre CpGV-M et CpGV-R5 a permis de mettre en évidence la coopération spécifique entre les deux génotypes. Ces travaux ont permis d’apporter quelques pistes d’amélioration pour les produits commerciaux à base de CpGV et leurs modes d’application en particulier de préconiser une augmentation des doses de CpGV pour contrôler les 2ème et 3ème générations d’insecteThe management of crop pests has always been an important issue. In modern agriculture, this management involves notably the use of insecticides increasingly respectful of environment and health. In the control of the apple pests Cydia pomonella, bioinsecticides based on the baculovirus CpGV have been used in Europe for almost 30 years. However, the massive use of a single viral genotype has led to the emergence and spread of resistant insects, compromising fruit productions. It has been shown that baculovirus diversity of genotypes persists in resistant insect populations even when insects have developed a specific resistance against some of these genotypes. The use of this diversity in biological control, especially to get each insect infected by several genotypes, represents a solution against insect resistance emergence.The objective of this research is to provide sustainable resistance management by exploring the benefits of multiple infections and viral genetic diversity in agronomic uses. This work is divided into two parts, one deals with the development and the other with the use of exploration methods of multiples infections in field and laboratory conditions. Two tools allowing the monitoring of different CpGV genotypes at different scales have been developed. The first tool is the adaptation of the ANCHORTM technology to baculoviruses, which makes them autofluorescent and allows the monitoring of each genotype within a cell. The second tool is the use of differences in the melting temperature of specifics fragments in their genomes (HRM), here the differential fragment of the pe38 gene was used. This tool enables to quantify the frequency of genotypes CpGV-M and CpGV-R5 in infected insect and to analyze a large number of samples, in order to establish the prevalence of genotypes in a population. These tools have been used both in field and laboratory to assess the dynamics of multiple infections. The study of interactions between CpGV-M and CpGV-R5 highlighted the specific cooperation between the two genotypes. These works have led to improvement paths in commercial CpGV-based products and their application methods in particular the recommendation of increased CpGV doses during the 2nd and 3rd generations of insects
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Bourne, J. M. "The importance of the host plant in the biological control of root-knot nematodes Meloidogyne spp. by the nematophagous fungus Verticillium Chlamydosporium." Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284315.
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Munoz, Cerda Gabriela Isabel. "Patterns in the infracommunity and component community structures of parasites in wrasses (Labridae): the importance of some biological characteristics of hosts and parasites /." [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19128.pdf.
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Carvalho, Simoes Francisco Manuel de. "Fish and mammalian glut4 traffic characteristics: an evolutionary perspective on the importance of glut4 protein motifs for trafficking." Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/662890.
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Glucose transporters (GLUTs) are extremely important for glucose metabolism. Glucose transporters uptake glucose from blood stream into the cells where it can be metabolized. Among the glucose transporters family, GLUT4, which is solely expressed in muscle and adipose tissues, displays a unique feature as it can change its cellular distribution within minutes in response to insulin to regulate glucose uptake. Therefore, the study of GLUT4 cellular trafficking is fundamental to understand its functioning and to deepen our knowledge on glucose homeostasis.
In this work, we utilized a GLUT4 fish variant, brown trout GLUT4, to study GLUT4 trafficking and the role of GLUT4 protein motifs in this process, in 3T3-L1 adipocytes. We observed that, in comparison to mammalian GLUT4 (RatGLUT4), brown trout GLUT4 (BtGLUT4) had a much weaker translocation to the plasma membrane in response to insulin which was in part due to a slower cellular trafficking (exocytosis and endocytosis) and to a poor targeting to the GLUT4 storage vesicles responsible for “holding” GLUT4 inside the cell in the absence of insulin; these vesicles represent the main pool of insulin-responsive GLUT4. In this thesis we also studied the most common GLUT4 endocytic routes. We analyzed the contribution of the clathrin-mediated and the cholesterol-dependent endocytic pathways for RatGLUT4 and BtGLUT4 internalization. We observed that whilst RatGLUT4 internalizes through both the clathrin-mediated and the cholesterol-dependent pathways, BtGLUT4 only utilizes the former. It has been suggested that in adipocytes, the main cholesterol-dependent internalization pathway is the caveolar route. The internalization through this pathway is mediated by plasma membrane structures called caveolae. The formation of these structures is dependent on the caveolin-1 protein. To analyze the role of caveolae in GLUT4 internalization we blocked its formation by knocking down caveolin-1 and observed an increase of RatGLUT4 and BtGLUT4 internalization; however, both GLUT4 isoforms showed less internalization through the clathrin-mediated and cholesterol-dependent pathways in the absence of cavolin-1. Therefore, we suggest that in 3T3-L1 adipocytes caveolin-1 knockdown induces internalization of GLUT4 through alternative pathways.
GLUT4 trafficking is regulated by cellular machinery that interacts with GLUT4 protein motifs. To analyze the role of the mammalian N-terminal FQQI8 and C-terminal TELEY502 motifs in GLUT4 trafficking we mutated the corresponding motifs in BtGLUT4 (FQHL8 and TELDY495, respectively) and observed that mutations in the C-terminal had little effect on BtGLUT4 trafficking whereas mutations on the N-terminal (especially FQQL8 mutant) improved BtGLUT4 intracellular retention in the absence of insulin. Furthermore, we verified that FQQL8 mutation increased BtGLUT4 retention in a syntaxin-6-rich compartment, possibly the trans-Golgi network. In addition to studying BtGLUT4 mutants we also analyzed the trafficking of a chimera consisting of a RatGLUT4 backbone with the large cytoplasmic loop of BtGLUT4 (L-GLUT4). We observed that L-GLUT4 possessed higher plasma membrane levels in the absence of insulin and as a result a weaker translocation. Moreover, we observed that this was caused, at least in part, by a reduction in the endocytosis of L-GLUT4 in the absence of insulin. We also analyzed the contribution of the clathrin-mediated and cholesterol-dependent pathways for L-GLUT4 internalization and observed that the loop substitution (L-GLUT4) reduced RatGLUT4 internalization through the cholesterol-dependent route. Moreover, in the absence of insulin and in caveolin-1, L-GLUT4 internalization did not increase as much as that of RatGLUT4. The internalization of L-GLUT4 in the absence of caveolin-1 and insulin occurred through a clathrin-mediated pathway, similarly to BtGLUT4, but it also internalized through a cholesterol-dependent pathway, unlike RatGLUT4 and BtGLUT4.
In summary, in this thesis we have contributed to increase the knowledge on GLUT4 trafficking and on the roles of the FQQI8 motif and large cytoplasmic loop in this process, in 3T3-L1 adipocytes.El transportador de glucosa GLUT4 tiene la capacidad de, en respuesta a insulina, cambiar su localización celular y de esta forma regular el transporte de glucosa. En este trabajo, hemos utilizado una variante de GLUT4 de trucha (BtGLUT4) para estudiar el trafico de GLUT4, así como sus dominios proteicos involucrados en este proceso, en adipocitos 3T3-L1. Hemos observado que en comparación con el GLUT4 de mamíferos (RatGLUT4), el BtGLUT4 tenia una menor capacidad de translocación a la membrana plasmática en respuesta a insulina y que esto se debía a una trafico celular mas lento (exocitosis y endocitosis) y a una peor retención en las vesículas responsables por retener el transportador dentro de la célula en ausencia de insulina. En este trabajo hemos observado que RatGLUT4 ha internalizado por la vía de endocitosis mediada por clatrina y por la vía dependiente de colesterol, mientras que BtGLUT4 solo ha utilizado la primera. Además, hemos inhibido la internalización caveolar, mediante bajada de la expresión de caveolina-1, y hemos observado un aumento de la internalización de RatGLUT4 y BtGLUT4. Con el objetivo de estudiar el papel del dominio FQQI8 (extremo -N) de mamífero en el trafico de GLUT4, hemos mutado la secuencia correspondiente en BtGLUT4 (FQHL8) y hemos observado que mutaciones en este dominio han mejorado la retención intracelular de BtGLUT4 en ausencia de insulina. También hemos estudiado el trafico de una quimera que consiste en la secuencia de RatGLUT4 con el lazo citoplasmático largo de BtGLUT4 (L-GLUT4). Hemos observado que la sustitución del lazo ha aumentado los niveles de RatGLUT4 en superficie en ausencia de insulina y que esto era debido, por lo menos en parte, a una menor endocitosis en ausencia de la hormona. También hemos observado que la sustitución del lazo de RatGLUT4 ha reducido su internalización a través de la vía dependiente de colesterol en ausencia de insulina. Además, en ausencia de caveolina-1 y insulina, la internalización de L-GLUT4 ha aumentado menos que la de RatGLUT4 y ha ocurrido a través de las vías mediada por clatrina y dependiente de colesterol.
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Clodore, Martine. "La vigilance : evolution circadienne et horaires de sommeil, importance de la typologie matin/soir." Paris 6, 1988. http://www.theses.fr/1988PA066153.
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Walker, Amanda L. "Working with sex offenders and those individuals with a learning disability : the importance of psychological factors in the delivery of care." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/3156/.
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This research study explores the importance of psychological factors in the delivery of care to individuals who are sex offenders and may have a learning disability. This is achieved through two different ways. A literature has been undertaken to question what the psychological impact is to those working with sex offenders. Findings showed that several potential harmful effects exist, which can be increased or reduced through a selection of moderating and protective factors. The authenticity of these outcomes is restricted by various methodological limitations which are described. The empirical study explores staff attitudes to working with sex offenders who have a learning disability. This cross-sectional study showed the importance of a staffs qualification, emotional response and level of burnout in determining their attitudes. Clinical implications, methodological limitations and future studies are provided. Finally a brief public domain paper provides a summary of these papers and offers recommendations for clinical practice.
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Osburn, James Roy. "Importance of the kappa opoid system for ultrasonic vocalizations of young rats: Role of peripherally-versus centrally-located kappa opioid receptors." CSUSB ScholarWorks, 2008. https://scholarworks.lib.csusb.edu/etd-project/3378.
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Freeman, Amanda N. D. "The importance of fisheries waste in the diet of Westland Petrels (Procellaria westlandica)." Lincoln University, 1997. http://hdl.handle.net/10182/298.
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Westland petrels Procellaria westlandica breed only near Punakaiki on the West Coast of New Zealand. About 80 km offshore from their breeding colony, New Zealand's largest commercial fishery (for hoki Macruronus novaezelandiae) operates from mid June to early September, coinciding with the Westland petrel's breeding season. It has been assumed that Westland petrels feed extensively on fisheries waste and that this habit has been at least partly responsible for the increase in the Westland petrel population. Some seabird biologists have expressed concern that if a species comes to depend on scavenging at fishing vessels, such a species could experience a food crisis if fishing operations changed in a way that reduced the quantity of waste discharged. The aim of this research was to assess how dependent Westland petrels have become on fisheries waste for food. Diet studies showed that during the hoki fishing season, waste accounts for more than half by weight of the solid food Westland petrels bring back to the colony to feed their chicks. After the hoki season, waste contributes only about a quarter of their diet as birds switch to more natural prey and scavenge a wider variety of fish species presumably from smaller, inshore fishing vessels. Much of the fisheries waste eaten by Westland petrels was flesh which could not be identified using traditional techniques. The electrophoretic technique iso-electric focusing increased the number of fish samples that could be identified and consequently the diet was interpreted differently than it would have been had only traditional diet analysis been used. The survey of Westland petrel distribution off the west coast of the South Island, found that although hoki fishing vessels influence the distribution of Westland petrels, only a small proportion of the Westland petrel population appears to utilise this food resource at any one time. Westland petrels were tracked at sea by VHF radio telemetry and then by satellite tracking. Satellite tracking showed that there is considerable variation in the amount of time Westland petrels spend in the vicinity of fishing vessels. On average, satellite tracked birds spent one third of their time near vessels, but they foraged over much larger areas than that occupied by the West Coast South Island hoki fishing fleet. Although fisheries waste is an important component of the Westland petrel diet, it appears that the situation is one of opportunistic use of a readily available resource, rather than one of dependence. Several features of the Westland petrel's breeding biology and foraging ecology suggest that Westland petrels could compensate for a reduction in waste from the hoki fishery by switching to other sources of waste and increasing their consumption of natural prey. Nevertheless, much remains unanswered concerning the role of fisheries waste in the Westland petrel's diet. In particular, quantifying the waste available to seabirds, and the success of Westland petrels in acquiring that waste compared to other scavenging species, is needed in order to better predict the effect of a reduction in fisheries waste on Westland petrel population size.
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Chailleux, Anaïs. "Importance des interactions multi-trophiques dans les agrosystèmes pour la mise au point d'une lutte biologique contre une espèce invasive." Thesis, Nice, 2013. http://www.theses.fr/2013NICE4030/document.
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Les interactions multi-trophiques jouent un rôle clé dans la structuration des agrosystèmes et régissent la dynamique des populations qui les composent. L’objectif de cette thèse fut (i) d’étudier la perturbation des interactions liée à une espèce invasive (Tuta absoluta) dans les cultures de tomates européennes, (ii) de rechercher de nouveaux auxiliaires autochtones, puis (iii) d’évaluer l’efficacité de ces auxiliaires lorsqu’ils sont intégrés dans l’agrosystème. Nous avons montré que de nouvelles interactions sont apparues suite à l’invasion, notamment la compétition apparente entre les aleurodes et T. absoluta en présence du prédateur généraliste et omnivore M. pygmaeus. Dans un second temps, nous avons recherché de nouveaux auxiliaires, en se focalisant d’abord sur les trichogrammes, Trichogramma achaeae étant déjà commercialisé contre T. absoluta en France. Les expérimentations de laboratoire et de terrain n’ont pas permis de mettre en évidence un trichogramme plus intéressant que celui déjà commercialisé. De plus, nous avons observé une prédation intra-guilde de M. pygmaeus sur les trichogrammes juvéniles i.e. œufs parasités, et nous avons montré que T. absoluta n’était pas un hôte approprié pour ces parasitoïdes. Les trichogrammes ne s’installant pas sur la culture, les études concernant les parasitoïdes oophages se sont arrêtées là et nous nous sommes intéressés aux parasitoïdes larvaires. La biologie de deux parasitoïdes larvaires a été étudiée et a souligné l’intérêt de Stenomesius japonicus (Eulophidae) en tant que potentiel agent de lutte biologique contre T. absoluta. Malgré les interactions négatives subies par le parasitoïde, des expérimentations sous serre en conditions réalistes ont montré que le prédateur et le parasitoïde larvaire pouvaient coexister pendant plusieurs mois. Cela a été montré y compris en présence d’une proie alternative pour le prédateur omnivoreMulti-trophic interactions play a key role in structuring agro-ecosystems and regulating arthropod population dynamics. The objective of the PhD was (i) to study the possible disruptions of biotic interactions owing to the recent invasion by T. absoluta in European tomato crops, (ii) to identify local natural enemies attacking T. absoluta, (iii) to evaluate their effectiveness against T. absoluta when integrated into the agro-ecosystem. We showed that new interactions occurred after the arrival of T. absoluta, mainly apparent competition between whiteflies and T. absoluta, in presence of the omnivorous and generalist predator M. pygmaeus. We recorded possible new biocontrol agents and focused first on Trichogramma parasitoids, as Trichogramma achaeae was promptly commercialized against T. absoluta in France. Laboratory and field experiments failed to detect promising Trichogramma strains. In addition, intraguild predation of M. pygmaeus on parasitoid juveniles i.e. parasitized eggs, was observed and we demonstrated that T. absoluta was not a suitable host for Trichogramma parasitoids. Therefore, further studies switched on parasitoids of larval stages of T. absoluta. We demonstrated the importance of Stenomesius japonicus (Eulophidae) as a possible biological control agent against T. absoluta. The parasitoid was able to reproduce on T. absoluta over several generations under laboratory and greenhouse conditions. Despite negative interactions between the predator and the larval parasitoid, further greenhouse experiments demonstrated that two competitors can coexist for several months. Moreover, the presence of an alternative prey for the omnivorous predator (whitefly) in the agro-ecosystem did not prompt larval parasitoid exclusion, and the parasitoid remained in the crop even in the presence of other prey for the predator
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Berry, Christopher J. J. "Post-dispersal seed predation in a conifer-broadleaf forest remnant : the importance of exotic mammals." Lincoln University, 2006. http://hdl.handle.net/10182/666.
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Despite extensive international acceptance of the critical role of mammalian post-dispersal seed predation in many plant communities, in New Zealand we have limited knowledge of these predators’ influence on plant recruitment in our forests. The principle objective of my thesis was to determine the importance of exotic mammals as post-dispersal seed predators in a New Zealand conifer-broadleaf forest remnant. To address this goal, I used a series of field-based experiments where the actions of different post-dispersal seed predators were separated by wire-mesh exclosures. My study was conducted at Mount Peel Forest Park Scenic Reserve, South Canterbury, New Zealand. Being a human modified conifer forest currently dominated by broadleaf species, it is typical of forest remnants in New Zealand. This presented an opportunity to study a wide range of both potential post-dispersal seed predators and broadleaf tree species. My findings indicate that exotic mammals are not only post-dispersal seed predators at Peel Forest, but are responsible for the majority of post-dispersal predation events observed. Ship rats (Rattus rattus) were the dominant post-dispersal seed predators, while brushtail possums (Trichosurus vulpecula), house mice (Mus musculus) and native invertebrates were also important post-dispersal seed predators for several tree species. Through use of time-lapse video and cafeteria experiments I found that exotic mammalian seed predators, when compared to native invertebrate seed predators, preyed upon larger-seeded plant species and were responsible for considerable seed losses of several tree species. However, exotic mammalian seed predators do share several foraging characteristics with native invertebrate seed predators, as predators foraged in similar habitats and responded in a similar way to changes in seed density. In investigating if post-dispersal seed predation by mammals had a flow-on effect to plant recruitment, I observed natural seedling densities at Peel Forest were significantly higher in the absence of mammalian seed predators, but I found no evidence that the presence of mammals significantly altered the overall species richness. At the community level, I did not find an interaction between habitat and exotic mammals, however I present evidence that for individual plant species a significant mammal : habitat interaction occurred. Consequently, even though my cafeteria experiment implied there was no significant difference in the overall amount of seed preyed upon within different habitats, the less favourable microsite conditions for germination under an intact continuous canopy allows mammals to exacerbate habitat-related patterns of seed mortality and have a noticeable effect on seedling establishment. In an effort to validate the use of manipulative experiments to predict the long-term effect of post-dispersal seed predation on plant dynamics, I attempted to link results of my cafeteria experiment with observed seedling abundance at Peel Forest. Seven tree species were used in this comparison and a strong correlation was observed. This result shows that the level of post-dispersal seed predation determined in the cafeteria experiment provided a good predictor of the effect of mammalian post-dispersal seed predation on seedling establishment. To fully gauge the impact of mammalian post-dispersal seed predators on seedling establishment, the relationship between these seed predators and the type of recruitment limitation experienced by a plant species was also investigated. By using a combination of seed addition, plot manipulations and seed predator exclusion I was able to investigate this relationship. I found evidence that seed limitation at Peel Forest is positively correlated with seed size, and that while mammalian post-dispersal seed predators can further reduce plant recruitment of plant species experiencing seed limitation, the influence of mammals in determining plant recruitment was limited for plant species experiencing microsite limitation. My study has proven that exotic mammals are now the dominant post-dispersal seed predators at Peel Forest, the amount of seed preyed upon varies among plant species, and post-dispersal seed predation by mammalian species can lead to differences in seedling richness and abundance. I proved that the influence of exotic mammals on seedling establishment is also linked to habitat structure and recruitment limitations. When combined these observations suggest that exotic mammalian post-dispersal seed predators may play an important role in determining landscape abundance and distribution of plants at Peel Forest.
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Le, Yannou-Cateine Maureen. "La myrmécochorie en nouvelle-Calédonie : importance du contexte et impact des fourmis introduites sur ce service." Thesis, Nouvelle Calédonie, 2017. http://www.theses.fr/2017NCAL0007/document.
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La biosphère traverse une crise de biodiversité pour laquelle les milieux insulaires sont l’épicentre. Les invasions biologiques y constituent l’un des principaux facteurs de forçage, notamment du point de vue de l’altération des mutualismes, pour le fonctionnement et le maintien des écosystèmes. Durant notre travail en Nouvelle-Calédonie, nous nous sommes intéressés à un groupe clé de voute pour le fonctionnement des écosystèmes, les fourmis, et leur implication vis-à-vis de la dispersion de graines (myrmécochorie). Nous avons réalisé la première identification de plantes autochtones myrmécochores, avec une prépondérance des espèces sur substrats ultramafiques. Puis, nous avons testé la dispersion par les fourmis sur ces substrats. Après avoir caractérisé les communautés selon un gradient de perturbation anthropique, nous avons évalué la dispersion et la contribution des fourmis invasives à ce service par rapport aux fourmis natives. Ainsi, Solenopsis geminata semble capable d'une meilleure dispersion que les espèces natives. A contrario, Wasmannia auropunctata exclue les espèces natives sans assurer de dispersion efficace. Dans le contexte d’un régime de perturbations intense, nos travaux illustrent une communauté néo-assemblée de fourmis, dominée par des exotiques dont certaines pourraient assurer un relai de fonction pour la dynamique des maquis. Nos travaux illustrent la « contexte dépendance » des impacts d’espèces invasives en fonction du niveau de perturbation anthropique. Ils permettent de discuter la contribution possible de ces fourmis pour la restauration après perturbation sur substrats ultramafiques, voire de leur valorisation en ingénierie écologiqueThe biosphere is experiencing a biodiversity crisis, which for islands are the epicenter. Biological invasions are there, one of the main drivers, especially regarding the alteration of mutualistic relationships for the functioning and the maintenance of ecosystems. Thus, during our work in New Caledonia, we focused on a key group for ecosystem functions: ants, and their involvement in seed dispersal (myrmecochory). We carried out the first assessment of this mutualism in New Caledonia with the identification of indigenous myrmechorous plants, with a preponderance of species on ultramafic soils. Then, we evaluated the magnitude of seed dispersal by ants on these soils. After the characterisation of ant communities across an anthropic disturbance gradient, we evaluated seed dispersal capabilities of exotic ant compared to native ones. Solenopsis geminata appears to offer a more efficient seed dispersal than natives. On the other hand, Wasmannia auropunctata excludes native species without ensuring effective dispersal. In the context of an intense disturbance regime, our work illustrates a neo-assembled community of ants, dominated by exotic ones, some of which could provide a function relay with respect to maintaining the dynamic of maquis. Our work illustrates the “context dependency” of invasive species’ impacts as a function of anthropogenic disturbance’s level. It also discusses the possible contribution of these ants in a context of restoration after disturbance of habitats on ultramafic substrates, or even their use in ecological engineering program
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Nghidinwa, Kirsti C. "Why are some species invasive? : determining the importance of species traits across three invasion stages and enemy release of southern African native plants in New Zealand." Lincoln University, 2009. http://hdl.handle.net/10182/1438.
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There are many factors that have been proposed to contribute to plant invasiveness in nonnative ecosystems. Traits of invading species are one of them. It has been proposed that successful species at a certain invasion stage share particular traits, which could be used to predict the behaviour of potentially invasive plants at the respective stage. Three main stages of invasion are distinguished: introduction, naturalization, and invasion. I conducted a stageand trait-based analysis of available data for the invasion of New Zealand by the flora of southern Africa. Using 3076 southern African native vascular plant species introduced into New Zealand, generalised linear mixed model analysis was conducted to assess association of several species traits with the three invasion stages. The results showed that plant traits were significantly associated with introduction but fewer traits were associated with naturalization or invasion, suggesting that introduction can be predicted better using plant traits. It has been also hypothesized that species may become invasive in non-native ecosystems because they are removed from the regulatory effects of coevolved natural enemies (Enemy Release hypothesis). A detailed field study of the succulent plant Cotyledon orbiculata var. orbiculata L. (Crassulaceae) was conducted in the non-native New Zealand and native Namibian habitats to compare the extent of damage by herbivores and pathogens. C. orbiculata is a southern African species that is currently thriving in New Zealand in areas seemingly beyond the climatic conditions in its native range (occurring in higher rainfall areas in New Zealand than are represented in its native range). As hypothesised, C. orbiculata was less damaged by herbivores in New Zealand but, contrary to expectation, more infected by pathogens. Consequently, the plant was overall not any less damaged by natural enemies in the non-native habitat than in its native habitat, although the fitness impacts of the enemy damage in the native and invaded ranges were not assessed. The results suggest that climatic conditions may counteract enemy release, especially in situations where pathogens are more prevalent in areas of higher rainfall and humidity. To forecast plant invasions, it is concluded that species traits offer some potential, particularly at the early stage of invasion. Predicting which introduced plants will become weeds is more difficult. Enemy release may explain some invasions, but climatic factors may offset the predictability of release from natural enemies.
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Camargo, Luiza Figueiredo. "Caracterização morfológica e molecular de Campoletis Foerster, 1869 (Hymenoptera, Ichneumonidae, Campopleginae), parasitoides de Spodoptera frugiperda (Smith, 1797) (Lepidoptera, Noctuidae)." Universidade Federal de São Carlos, 2014. https://repositorio.ufscar.br/handle/ufscar/2107.
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Previous issue date: 2014-03-26Universidade Federal de Sao Carlos
The fall armyworm Spodoptera frugiperda (SMITH, 1797) is a voracious pest of numerous crops of economic importance throughout the New World. In Brazil, their larvae can be attacked by several species of parasitic wasps, which are candidate to biological control agents against this pest. Surveying the parasitoid fauna on S. frugiperda in maize throughout Brazil two very morphological similar species of Campoletis are found. To ensure the efficiency of the biological control works, the knowledge about the taxonomy of the species related is necessary. Campoletis specimens emerged from Spodoptera frugiperda were studied mofologically and molecularly, in order to solve taxonomic problems among C. sonorensis (CAMERON, 1886) and C. flavicincta (ASHMEAD,1890). The samples came from three regions of Brazil: Santa Maria, RS; Ribeirão Preto, SP; Sete Lagoas, MG. Pictures from the type material of the two species were studied, besides the original descriptions of them. A possible sinonimy is indicated between the both species, for which the name C. sonorensis will be used based on the priority law for species names. A redescription is made to Campoletis sonorensis from Brazil, using morphological characters and DNA Barcoding.
Spodoptera frugiperda (SMITH, 1797) é uma praga voraz de diversas culturas de importância econômica no Novo Mundo. No Brasil, suas larvas podem ser atacadas por diversas espécies de vespas parasitóides que são candidatos a agentes de controle biológico contra essa praga. Pesquisando os parasitóides da fauna de Spodoptera frugiperda em cultivos de milho no Brasil, duas espécies do gênero Campoletis, muito similares morfologicamente, foram encontradas. Para garantir a eficiência dos trabalhos de controle biológico, é de grande importância o conhecimento taxonômico das espécies relacionadas. Exemplares de Campoletis emergidos de Spodoptera frugiperda foram estudados morfológica e molecularmente, a fim de resolver os problemas taxonômicos existentes entre as espécies C. sonorensis (CAMERON, 1886) e C. flavicincta (ASHMEAD,1890). Os exemplares foram provenientes de três regiões do Brasil: Santa Maria, RS; Ribeirão Preto, SP; Sete Lagoas, MG. Fotos de material tipo das duas espécies foram estudadas, além das suas descrições originais. Os resultados indicam uma possível sinonímia entre as duas espécies, para a qual será usado o nome C. sonorensis com base na lei da prioridade para o nome das espécies. Apresentamos uma redescrição para Campoletis sonorensis usando caracteres morfológicos e de DNA Barcoding.
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Iqbal, Mazhar. "Synthesis of biologically important cyclopentenones." Thesis, University of Liverpool, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420456.
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Gamsjaeger, Roland. "AFM and SPR on biological systems applying atomic force microscopy (AFM) and surface plasmon resonance (SPR) to biologically important systems." Saarbrücken VDM Verlag Dr. Müller, 2007. http://d-nb.info/988909820/04.
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Guyon, Léna. "Auto-assemblages constitués de peptides pénétrants et de ferrocifène : une plateforme innovante pour le traitement du cancer du poumon Self-assembly of peptide-based nanostructures: Synthesis and biological activity Importance of combining advanced particle size analysis techniques to characterize cell penetrating peptide-ferrocifen self-assemblies." Thesis, Angers, 2019. http://www.theses.fr/2019ANGE0044.
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L’objectif de ces travaux était de développer un nouveau type de nanoparticule permettant le transport des ferrocifènes, en combinant trois stratégies de vectorisation : l’utilisation de peptides pénétrants, la formation d’une prodrogue amphiphile et leur auto-association potentielle. La synthèse des conjugués (CPP-p54) formés de deux types de peptides pénétrants différents Argn-p54 (n = 6 à 9) et RLW-p54, leur auto-assemblage dans l’eau ainsi que la caractérisation complète des objets formés ont été réalisés, tout en soulevant l’importance des méthodes de caractérisation employées pour caractériser l’objet réellement formé. Des études in vitro ont également été menées sur des cellules cancéreuses et des cellules pulmonaires saines démontrant une amélioration de l’activité biologique d’un facteur 9The aim of this project was to develop a new type of nanoparticle in order to transport ferrocifen molecules, combining three different strategies : the use of cell-penetrating peptides (CPPs), prodrug and their potential self-association. The synthesis of conjugates (CPP-p54) consisting of two different types of cell-penetrating peptides Argn-p54 (n=6 to 9) and RLW-p54, their self-assembly in waterand the complete characterization of the self-assemblies were carried out, by highlighting the importance of the methods used to characterize the suspension. In vitro studies were also performed on healthy cell line and lung cancer cells showing an improvement in biological activity by a factor 9
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Gore, Jeffrey. "Nonradioactive labelling of biologically important molecules." Title page, contents and abstract only, 1996. http://hdl.handle.net/2440/18711.
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Keeley, Deborah Michelle. "Electrochemical studies of biologically important materials." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325879.
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Cañari, Chumpitaz Cristhian. "Selenium a little known element with an important biological role." Revista de Química, 2013. http://repositorio.pucp.edu.pe/index/handle/123456789/100427.
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El selenio (Se) es un micronutriente esencial presente en diversos organismos incluyendo a los seres humanos. Este elemento puede presentarse en diversas formas metabólicas orgánicas e inorgánicas siendo la más importante la selenocisteína (Sec). La incorporación de Sec en las selenoproteínas emplea un mecanismo único que involucra la recodificación del codón UGA. Este proceso requiere la presencia fragmentos extra en el ARNm como la secuencia de inserción de selenocisteína (SECIS). En la actualidad, la función de muchas selenoproteínas se desconoce, aunque algunas están involucradas en la regulación redox de señales intracelulares, homeostasis redox y el metabolismo de la hormona tiroidea. La deficiencia de selenio afecta a la salud humana y se manifiesta en enfermedades como el cáncer, la enfermedad de Keshan y disfunciones hormonales.Selenium is an essential micronutrient present in various organisms including human beings. This element may be found in different organic and inorganic metabolites, and selenocysteine (Sec) is the most important. The insertion of Sec in selenoproteins uses a unique mechanism that involves the recoding of the UGA codon. This process requires new RNA fragments like the selenocysteine insertion sequence (SECIS) in the mRNA. The function of many selenoproteins is not known completely; however, some of them are involved in intracellular redox signaling regulation, redoxhomeostasis and thyroid hormone metabolism. Se deficiency in humans affects human health and results in diseases such as cancer, Keshan disease and hormonal disfunctions.
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Ventura, Valeria Victoria. "Structure analysis of biologically important prokaryotic glycopolymers." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/39368.
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Of the many post-translational modifications organisms can undertake, glycosylation is the most prevalent and the most diverse. The research in this thesis focuses on the structural characterisation of glycosylation in two classes of glycopolymer (lipopolysaccharide (LPS) and glycoprotein) in two domains of life (bacteria and archaea). The common theme linking these subprojects is the development and application of high sensitivity analytical techniques, primarily mass spectrometry (MS), for studying prokaryotic glycosylation. Many prokaryotes produce glycan arrangements with extraordinary variety in composition and structure. A further challenge is posed by additional functionalities such as lipids whose characterisation is not always straightforward. Glycosylation in prokaryotes has a variety of different biological functions, including their important roles in the mediation of interactions between pathogens and hosts. Thus enhanced knowledge of bacterial glycosylation may be of therapeutic value, whilst a better understanding of archaeal protein glycosylation will provide further targets for industrial applications, as well as insight into this post- translational modification across evolution and protein processing under extreme conditions. The first sub-project focused on the S-layer glycoprotein of the halophilic archeaon Haloferax volcanii, which has been reported to be modified by both glycans and lipids. Glycoproteomic and associated MS technologies were employed to characterise the N- and O-linked glycosylation and to explore putative lipid modifications. Approximately 90% of the S-layer was mapped and N-glycans were identified at all the mapped consensus sites, decorated with a pentasaccharide consisting of two hexoses, two hexuronic acids and a methylated hexuronic acid. The O-glycans are homogeneously identified as a disaccharide consisting of galactose and glucose. Unexpectedly it was found that membrane-derived lipids were present in the S- layer samples despite extensive purification, calling into question the predicted presence of covalently linked lipid. The H. volcanii N-glycosylation is mediated by the products of the agl gene cluster and the functional characterisation of members of the agl gene cluster was investigated by MS analysis of agl-mutant strains of the S-layer. Burkholderia pseudomallei is the causative agent of melioidosis, a serious and often fatal disease in humans which is endemic in South-East Asia and other equatorial regions. Its LPS is vital for serum resistance and the O-antigen repeat structures are of interest as vaccine targets. B. pseudomallei is reported to produce several polysaccharides, amongst which the already characterised 'typical' O-antigen of K96243 represents 97% of the strains. The serologically distinct 'atypical' strain 576 produces a different LPS, whose characterisation is the subject of this research project. MS strategies coupled with various hydrolytic and chemical derivatisation methodologies were employed to define the composition and potential sequences of the O-antigen repeat unit. These MS strategies were complemented by a novel NMR technique involving embedding of the LPS into micelles. Taken together the MS and NMR data have revealed a highly unusual O-antigen structure for atypical LPS which is remarkably different from the typical O-antigen. The development of structural analysis tools in MS and NMR applicable to the illustrated types of glycosylation in these prokaryotes will give a more consistent approach to sugar characterisation and their modifications thus providing more informative results for pathogenicity and immunological studies as well as pathway comparisons.
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Pandit, Bijan Kumar. "Solution thermodynamics of some biologically important compounds in various aqueous media." Thesis, University of North Bengal, 2019. http://ir.nbu.ac.in/handle/123456789/3645.
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