Plants do not harvest the whole solar spectrum equally at the different wavelengths. They indeed reflect green, absorbs red and blue, so that we see them green. The consequence of that is that the solar spectrum is actually not optimised for energy conversion. However, incoming solar spectrum can be modified in order to shift less efficient wavelengths to more efficient one (like green to red) using fluorescent pigments or phosphors. In this way, photosynthesis efficiency can be increased. Meanwhile, when one uses standard fluorescent pigments implemented in a coating at the top of a greenhouse, half of the converted sunlight is emitted back to space due to their isotropic emission, thus lowering the conversion efficiency. To overcome this limit, we propose to use the properties of nano antennas for which it has been shown that they can change the emitting direction of pigments when they are placed in their vicinity. We will design a greenhouse coating that enhance photosynthesis by increasing the effective light inside greenhouses using coatings having nano-antenna phosphor pairs. Firstly, we will perform numerical calculations considering near field radiation and fluorescence, in order to find an optimum design in terms of antenna and phosphor size. Then, the coating will be produced in collaboration with a deposition facility using corresponding parameters from the numerical study. Finally, the actual design will be characterised using spectroscopy to determine the discrepancy between numerical and experimental study. Further actions like changing numerical solver and/or fabrication methods will be considered after a feedback from the two studies.
Partners: University of Leeds, University of Poitiers
Host-parasite interactions are pervasive throughout the natural world, forming a critical component of plant and animal communities. Among them, parasites that distort host sex ratios are widespread in invertebrates. The effect of sex ratio distorters can have a powerful effect on biodiversity; they can cause populations to become extinct and change the composition of animals in the community. Additionally as they can affect harmful as well as beneficial hosts, there is currently a great deal of interest in the use of such parasites for biological control. Sex ratio distortion has evolved in diverse parasites (eukaryotes and bacteria) and affects diverse hosts. Why distort sex ratio? These parasites are passed from mother to offspring in the eggs and are only transmitted by females. These parasites have evolved a number of strategies to increase the relative frequency of female hosts (so increasing the spread of the parasite). Feminisation is induced by the bacterium Wolbachia and by microsporidia (eukaryotic parasites) in Crustacea. In contrast Wolbachia causes male killing in insects. Discovering the mechanisms of male killing and feminisation is key to understanding host-parasite coevolution. We propose that these intracellular parasites are most likely to act by secreting molecules into the host cell which will then influence host molecular pathways, they may modify the response to external hormonal signals or even induce programmed cell death (apoptosis). Such changes could disrupt patterns of sexual development or lead to sex-specific embryo mortality. AIMS: We will investigate the evolution of sex ratio distortion in distantly related parasites by testing the hypotheses that - Similar mechanisms lead to contrasting strategies of sexual manipulation by Wolbachia (male killing in insect hosts, feminisation in crustacean hosts) - Parallel mechanisms of feminisation have evolved in distantly related parasites (Wolbachia and microsporidia) OBJECTIVES I. WE WILL INVESTIGATE THE MOLECULAR BASIS OF WOLBACHIA INDUCED MALE KILLING AND FEMINISATION. We will use state of the art techniques (proteomics) to identify molecules secreted into the host cytoplasm that cause feminisation or male killing, and to follow the changes they induce in the host. We will study this initially in the Drosophila (fruit fly)/Wolbachia male killing system. The genome of both these organisms is known and will help us to identify proteins and their function. We will then go on to study feminising Wolbachia in the crustacean Armadillidium vulgare (woodlouse). II. WE WILL INVESTIGATE THE CELLULAR BASIS OF WOLBACHIA AND MICROSPORIDIA INDUCED FEMINISATION BY TESTING FOR MANIPULATION OF THE PATTERN OF CELL DEATH IN THE DEVELOPING HOST Parasites cause feminisation in Crustacea by inhibiting development of the androgenic gland (the gland that controls male sexual differentiation). To pinpoint the site of action, we will map the distribution of feminising microsporidia and Wolbachia during sexual differentiation of their crustacean hosts. We have recently observed an association between male killing in Drosophila bifasciata by Wolbachia and apoptosis (programmed cell death). We will test whether feminising parasites also induce apoptosis in the androgenic gland in order to feminise the host.
Partners: University of Poitiers, University of Glasgow, Haldor Topsoe A/S
Ammonia synthesis by the Haber Bosch Process is a large scale reaction of major importance since it forms the basis of synthetic fertiliser production, with ca 85% of the ammonia produced being used to feed crops. It has been estimated that the fertiliser produced via the Haber Bosch Process sustains 40% of the current global population. This reaction is becoming more and more important as demand for food increases along with population growth. As operated currently, which involves large scale chemical plants operating at high reaction pressures and temperatures employing hydrogen feedtsocks generated from fossil fuel sources, the Haber Bosch Process is responsible for the consumption of 1-2% of manmade energy and it also results in about 1.6% of the manmade CO2 released to the atmosphere. The aim of this research is to discover and develop new catalysts which can operate in smaller reactors on a local scale such that fertilisers can be prepared close to their point of use. This will cut down on the CO2 footprint of the process since it would be possible to use feedstocks which are non-fossil fuel based and are derived from renewable energy souces such as wind power and also it would negate the requirement for transportation of fertiliser over long distances. The development of such smaller localised ammonia production units, which could be started up and shut down quickly, would require more active catalysts able to work at lower pressures than those currently employed. In this work we are using a combination of computer modelling and experiments to develop such new catalysts. The new localised sustainable ammonia production capabailities which would result from success in this area would also have impact on the growing interest in using ammonia as a fuel to replace the CO2 producing fossil fuels such as petrol and diesel currently employed.