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University of Guelph

University of Guelph

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24 Projects, page 1 of 5
  • Funder: UK Research and Innovation Project Code: EP/G015325/1
    Funder Contribution: 313,341 GBP

    The biological membrane is a highly organised structure. Many biologically active compounds interact with the biological membrane and modify its structure and organisation in a very selective manner. Phospholipids form the basic backbone structure of biological membranes. When phospholipid layers are adsorbed on a mercury drop electrode (HMDE) they form monolayers which have a very similar structure and properties to exactly half the phospholipid bilayer of a biological membrane. The reason for this is that the fluid phospholipid layer is directly compatible with the smooth liquid mercury surface. The great advantage of this system is that the structure of the adsorbed phospholipid layer can be very closely interrogated electrochemically since it is supported on a conducting surface. In this way interactions with biologically active compounds which modify the monolayer's structure can be sensed. The disadvantage is that Hg electrodes are fragile, toxic and have no applicability for field use in spite of the sensitivity of the system to biological membrane active species. Another disadvantage is that the Hg surface can only be imaged with extreme difficulty. This project takes the above proven sensing system and modifies it in the following way. A single and an array of platinum (Pt) microelectrode(s) are fabricated on a silicon wafer. On each microelectrode a minute amount of Hg is electrodeposited and on each Hg/Pt electrode a phospholipid monolayer is deposited. The stability of each phospholipid layer will be ensured through the edge effect of the electrode. We will use the silicon wafer array to carry out controlled phospholipid deposition experiments which are not possible on the HMDE. We shall also try out other methods of phospholipid deposition. The project will exploit the fact that the microelectrode array system with deposited phospholipid monolayers is accessible for imaging. AFM studies at Leeds have already been used to image temperature induced phase changes in mica supported phospholipid bilayers showing nucleation and growth processes. The AFM system is eminently suitable therefore to image the potential induced phase changes of the phospholipid monolayers on the individual chip based microelectrodes. It is important to do this because the occurrence of these phase transitions is very sensitive to the interaction of the phospholipid layer with biomembrane active species.In addition the mechanism of the phase changes which are fundamentally the same as those occurring in the electroporation of cells are of immense physical interest and a greater understanding of them can be gained through their imaging. We shall also attempt to image the interaction of the layer with membrane active peptides at different potential values. The AFM system will be developed to image the conformation and state of aggregation of adsorbed anti-microbial peptides on the monolayer in particular as a function of potential change. When biomembrane active compounds interact with phospholipid layers on Hg they alter the fluidity and organisation of the layers. This in turn affects the characteristics of the potential induced phase transitions. This can be very effectively monitored electrochemically by rapid cyclic voltammetry (RCV). Interferences to the analysis will be characterised. Pattern recognition techniques will be developed to characterise the electrochemical response to individual active compounds.The project will deliver a sensor on a silicon wafer which has the potential to detect low levels of biomembrane active organic compounds in natural waters and to assess the biomembrane activity of pharmaceutical compounds. The proven feasibility of cleaning the Hg/Pt electrode and renewing the sensing phospholipid layer will facilitate the incorporation of the device into a flow through system with a full automation and programmable operation.

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  • Funder: UK Research and Innovation Project Code: NE/T014733/1
    Funder Contribution: 10,155 GBP

    AHRC : Jessica Robins : AH/R504671/1 "Breaking Eggs" is an exciting project sharing knowledge between the UK and Canada. The project invites residents of Guelph, Wellington to take part in a series of hands-on workshops responding to the beginning of Our Food Future project, a city wide, 5-year project that aims to use technological innovation to make the region a sustainable food hub for Canada. Our Food Future is a multi-million-dollar project that will use technology to radically change the way food is grown, distributed and consumed. The project will make Guelph the world's first circular food city, using technology to make sure everyone has enough to eat and waste is eliminated, while restoring natural systems. The workshops will use creative methods to help local community members explore the wider project and examine avenues for their engagement. It will look at what opportunities' residents could take advantage of, and what challenges communities could face during this transition. Breaking Eggs will take place in the first year of the Our Food Future project so will give residents of different local communities a chance to be involved in shaping the project. The workshops will invite people from all parts of Guelph and Wellington County to take part in sharing ideas and creating a new future for the region. The lessons learned through the project will be brought back to the UK and the knowledge gathered will be shared so that other communities can look at ways they can engage in more sustainable food systems for their region.

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  • Funder: French National Research Agency (ANR) Project Code: ANR-14-CE05-0050
    Funder Contribution: 467,689 EUR

    The recent expansion of the unconventional gas industry in North America and its potential advent in Europe has generated public concern regarding the protection of groundwater and surface water resources from contamination by stray gas, saline formation water and fracturing chemicals. A major scientific challenge and an indispensible prerequisite for environmental impact assessment in the context of unconventional gas development is the determination of the non-impacted baseline conditions against which potential environmental impacts on shallow water resources can be accurately and quantitatively tested. The objective of this Franco-Canadian NSERC-ANR project is to develop an innovative and comprehensive methodology of geochemical and isotopic characterization of the environmental baseline for water and gas samples from all three essential zones: (1) the production zone, including flowback waters, (2) the intermediate zone comprised of overlying formations, and (3) shallow aquifers and surface water systems where contamination may result from diverse natural or other human impacts. The outcome will be the establishment of a methodology based on innovative tracer and monitoring techniques for detecting and quantifying and modeling stray gas and leakage of saline formation water mixed onto flowback fluids into fresh groundwater resources and surface waters taking into account the mechanisms of fluid and gas migration. The new knowledge derived from this project will be of critical importance for ensuring the environmentally acceptable development of unconventional energy resources in Canada and Europe. Decision support and recommendations for stakeholders on meaningful baseline and monitoring programs in the context of unconventional energy resources will be provided as final deliverable.

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  • Funder: French National Research Agency (ANR) Project Code: ANR-17-CE02-0021
    Funder Contribution: 468,344 EUR

    It is now recognised that DNA can move across species barriers, not only in bacteria and archaea, where this has been long-recognised, but also among eukaryotes, including metazoans. In the latter however, Horizontal Transfers (HTs) are only documented from a few case studies, providing us with a highly-fragmented picture of which genetic elements can actually move, and by what processes. Evidence for HT between insect parasitoids and the hosts in which they develop indicates that this tight ecological connectivity can allow the transmission of DNA. Other data sets suggest that Transposable Elements (TEs) tend to be exchanged most frequently between closely related lineages, possibly because of the resemblance between the donor and recipient organisms. Building on these observations, we hypothesize here that ecological connectivity and phylogenetic relatedness represent the major determinants of HT. To test this hypothesis, we will combine full genome sequencing with the results of 40 years of field work in a Costa Rican National Park that have exhaustively documented the network of interactions between Lepidoptera caterpillars and their parasitoids. We take advantage of the DNA-barcoding campaign that has complemented the ecological dataset since 2004, and produced molecular markers and DNA extracts from over 200,000 specimens, distributed across 5000+ species of Lepidoptera and their 2000+ species of parasitoids, both Diptera and Hymenoptera. The available molecular data provides a useful phylogenetic framework which will be used in combination with the ecological network to select 250 species, each represented by two specimens, from which we will produce full genomes. The available DNA extracts are readily usable for full genome sequencing, as demonstrated by a preliminary sequencing experiment that we performed since the submission of our pre-proposal. In the first year and first Task of the project, we will sequence and assemble the genomes. In the second task, we will document patterns of HT, that is, produce an exhaustive catalogue of transfer events using a combination of two approaches: (1) we will compute the genetic distance at all homologous regions between hosts and parasitoid genomes, to detect very similar sequences, that are indicative of recent host-parasitoid HTs; (2) a more complete picture will be obtained using cophylogenetic approaches (that is, comparisons between species trees and gene-specific trees) that will reveal ancient transfers, as well as transfers between closely related species (e.g. between two hosts or two parasitoids). These analyses will be applied to the various kinds of genetic entities present in our data set: nuclear genomes (distinguishing transposable elements from non-mobile nuclear DNA), intracellular bacteria and viruses. Following this descriptive step of the project, we will be in position to investigate the processes underlying HTs, in the third Task of the project. Specifically, we will test the hypothesis that ecological connectivity and phylogenetic distance are the two major factors affecting the passage of DNA across species. Having assessed the amount of HTs that have occurred between hosts and parasitoids, we will test the correlation between the ecological network and HT patterns. We will also investigate the possibility of HTs between two parasitoids or between two hosts through a shared prey or predator. Using such within-group transfers, we will analyse the relationship between the phylogenetic distance and the rate of HT between lineages. While challenging both in its scale and in the complexity of the questions being addressed, the Horizon project involves a team of highly complementary researchers, datasets and methods, from field ecology to phylogenomics, that will provide major breakthrough in our understanding of horizontal DNA transfer in metazoans, and the possibly vast evolutionary implications of this fascinating phenomenon.

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  • Funder: UK Research and Innovation Project Code: NE/E015212/1
    Funder Contribution: 389,323 GBP

    Iceland represents a natural laboratory for studying the colonization of freshwater habitats by fish since rivers and lakes all date from the end of the last Ice-Age less than 10,000 years ago. The North Atlantic provided a refuge for species such as arctic charr (Salvelinus alpinus) which invaded freshwater once the ice retreated. New habitats and the lack of competing species led to the appearance of different forms of Artic charr, called morphs. In particular, 27 discrete populations of dwarf charr have been identified with specialised feeding morphology that enables them to exploit the small larval fissures on the bottom of streams and lakes. Our Icelandic and Canadian partners have collected an enormous amount of data on each of the dwarf populations including, habitat characteristics (temperature and bottom type), diet, maximum body size, size and age at sexual maturity and cranial morphology. Other studies in progress on rapidly evolving DNA sequences we will enable us to determine the relationships between each population and estimate which ones arose independently allowing us to study the repeatability of evolution for populations living in similar habitats. Studies involving such diverse organisms as worms, flies and vertebrates suggest that poor nutrition alone is sufficient to produce dwarfism via effects on the signaling pathways controlled by the hormone Insulin-like growth factor-I (IGF-I): indicating a universal and conserved biological mechanism. Intriguingly, in the zebrafish, which is often used for studies of development, so-called 'knock-outs' of an IGF-binding-protein gene also caused alterations to the shape of the head which are reminiscent of those found in dwarf charr. We will therefore experimentally test the hypothesis that interactions between the environment and the IGF-hormone system during development can produce the specialised jaw and cranial morphology characteristic of the dwarf phenotype. Since early development in fish is entirely dependent on genetic messages passed through the egg yolk we will conduct experiments to determine whether it is the environment of the mother, the embryo or both that are important for producing fish with dwarf characteristics. Thingvallavatn, the largest and oldest lake in Iceland, contains four Arctic charr morphs, including a dwarf form, which are specialised to exploit different habitats. Laboratory breeding experiments have shown that the large differences in body size, morphology and life history such as the size at sexual maturity are heritable. This suggests that intense competition between morphs and reproductive isolation has resulted in natural selection and specialization for characters helping each morph to survive in their chosen environment. Previously we showed that dwarfism in the Thingvallavatn charr has resulted in a reduction in the number of muscle fibres in the trunk, which is thought to lower costs of maintenance relative to the ancestral charr. By studying a large number of Arctic charr populations (15 dwarfs and 5 generalists) we will test the generality of the hypothesis that the relative importance of developmental plasticity versus selection for setting muscle fibre number is related to the age and stability of the habitat and is different depending on whether there is competition with other morphs. The research is important because it addresses the fundamental question of how natural selection and plasticity operate to produce different forms of the same species at the level of physiological systems. The evolution of different morphs of the same species is relatively common and is found, for example, in sticklebacks and African cichclids. The practical application of this research is in understanding how the biodiversity of fish populations arises and how it may be conserved for future generations.

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