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1
Lüthy, Barbara. "Linolensäure-abhängige Chlorophyll-Bleichung /". [S.l.] : [s.n.], 1985. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=7872.
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Walker, John Stuart. "Autoxidation reactions of chlorophyll". Thesis, University of York, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403864.
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Bosch, Jennifer. "Satellite-Measured Chlorophyll Variability Within the Upwelling Zone Near Heceta Bank, Oregon". Fogler Library, University of Maine, 2002. http://www.library.umaine.edu/theses/pdf/BoschJ2002.pdf.
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Hörtensteiner, Stefan. "Chlorophyll breakdown in higher plants /". Zürich : [s.n.], 1999. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000254617.
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Woolley, Paul Simon. "Spectroscopic studies of chlorophyll transformations". Thesis, University of York, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387546.
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Dash, Jadunandan. "The MERIS terrestrial chlorophyll index". Thesis, University of Southampton, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420238.
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Haas, Eva Katharina. "Clomazone action and chlorophyll biosynthesis". Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389121.
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Chidgey, Jack. "Investigations into synechocystis chlorophyll synthase". Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/7893/.
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The first stage of photosynthesis involves the capture of light by pigment molecules bound within membrane-associated protein complexes. Arguably the most important of these pigments are the chlorophylls, tetrapyrrole molecules with a centrally-coordinated Mg2+ ion, a fifth ring and a long hydrophobic tail. Chlorophyll biosynthesis occurs in a stepwise manner, starting with chelation of the Mg2+ and ending with the addition of the tail via a reaction catalysed by chlorophyll synthase (CS). Then, there is handover of newly-synthesised chlorophylls to the apparatus for assembling photosynthetic complexes, in a poorly-understood process that likely involves CS. This handover process was investigated by FLAG-tagging the Synechocystis CS. Following immunoprecipitation an enzymatically active protein-pigment complex was retrieved containing the high-light-inducible protein HliD, the membrane insertase YidC and the putative photosystem II assembly factor Ycf39. This is the first evidence for a link between Chl biosynthesis and YidC-dependent co-translational insertion of nascent light-harvesting polypeptides into membranes. Analysis of similar pull-down experiments carried out on cells before and after light shock revealed that CS continues to interact with the HliD and YidC proteins during light shock whilst the interaction of CS with Ycf39 is abolished. Further analysis indicated that the light shock treatment causes a rearrangement of the remaining proteins implying different chlorophyll handover systems may be employed during assembly and repair of light harvesting and reaction centre complexes. Preliminary kinetic characterisation of FLAG-purified CS was carried out using a chlorophyllide substrate produced by a Rba. sphaeroides mutant. Km values of 25.7 μM ± 19.2 and 66.8 ± 33.1 μM for chlorophyllide and geranylgeranyl pyrophosphate, respectively, were obtained. An artificial gene was designed encoding a polypeptide representing the loop regions of CS; the expressed, purified polypeptide was used to raise a synthase antibody, which will be useful for future studies of this enzyme.
9
Schmidt, Kristin. "Pigmentbindung verschiedener Mitglieder der erweiterten Chlorophyll-a-b-Proteinfamilie und des wasserlöslichen Chlorophyll-Proteins WSCP". [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968710921.
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Hodges, Benjamin A. "On the distribution of oceanic chlorophyll". Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3225896.
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Thesis (Ph. D.)--University of California, San Diego, 2006.Title from first page of PDF file (viewed October 8, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 139-143).
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Hodges, M. "Chlorophyll fluorescence and thylakoid membrane organisation". Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37728.
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Pinto, Elizabeth A. "Regulation der Zeaxanthin- und der Diatoxanthin-Epoxidase in Chlorophyll-a-b- und Fucoxanthin-Chlorophyll-a-c-haltigen Pflanzen". [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975913409.
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White, Michael J. "Developmental and immunological studies on chlorophyll proteins". Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/27564.
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All the chlorophyll in higher plants is bound to specific proteins. These chlorophyll-proteins absorb light energy which is used by the electron transport processes of the photosynthetic apparatus. The synthesis and assembly of the photosynthetic apparatus and chlorophyll proteins is regulated by light and other factors which are incompletely understood. Antibodies were used to investigate the accumulation of chlorophyll proteins in plant systems which were completely lacking one or more of the factors involved in chlorophyll protein synthesis or degradation. Immunological cross-reactions among the chlorophyll a + b apoproteins were observed and characterized, and theoretical work was undertaken to predict the probability that immunological cross-reactions may arise due to chance arrangement of amino acids.
Chlorophyll a+b protein complexes associated with photosystem I were isolated and characterized. These included a light-harvesting antenna complex (LHCI), which was shown to contain Chi a, some Chi b, and four polypeptides of 21-24 kDa. This complex was isolated from CP Ia complexes, which also contain the P700 chlorophyll a protein, CP I. Antibodies were raised against the chlorophyll a + b protein complexes of both the photosystem I antenna (LHCI) and the photosystem II antenna (CP II and CP 29), and against the chlorophyll a protein containing the photosystem I reaction center (CP I). Antibodies to LHCI were obtained by using highly purified CP Ia as an antigen.
When antisera to Chi a + b proteins were reacted with the entire electrophoretic spectrum of denatured thylakoid proteins, they cross-reacted with the polypeptides belonging to other Chi a+b proteins. The strongest cross-reactions were observed between antibodies to CP Ia and the polypeptides of the photosystem II complexes, CP II and CP 29. These cross-reactions observed with anti-CP Ia were shown not to be due to antibodies to CP I, but rather to antibodies directed against the photosystem I antenna complex, LHCI. Affinity-purification of the anti-CP Ia antibodies did not eliminate these cross-reactions. The data suggest there are amino acid sequence similarities among the chlorophyll a/b-binding polypeptides.
Theoretical work was undertaken to determine if these cross-reactions were expected due to chance alone or not. Attempts to address this question led to the synthesis of a mathematical model to predict the probability that antibodies will react with proteins other than the antigen they were raised against. This theoretical work was done as a collaboration with Peter Sibbald of our lab, with input from Dr. Michael Waterman, one of the mathematicians whose work this model is based on. The sequence similarities predicted to exist among the chlorophyll a+b proteins appear to be more extensive than those which would be expected to arise due to chance alone. It is postulated that the Chi 0+6 proteins may have arisen from a common ancestral gene.
At least some polypeptides belonging to each of the three Chi a + b
proteins, including those of CP 29 and LHCI, were found in the Chi Mess
barley (Hordeum vulgare L.) mutant chlorina f2. Similar experiments were
performed on barley grown under intermittent light, which also completely lacks Chi b. Only two polypeptides belonging to the Chi a+b proteins were found under these conditions. Taken together with published studies in the literature, these results provide evidence for the existence of differing posttranscriptional controls among the various chlorophyll proteins, and between these two systems.
Antibodies were also used to determine the kinetics of synthesis of the chlorophyll-binding polypeptides during the light-induced greening of dark-grown barley. The chlorophyll a + b antenna polypeptides of both photosystems were absent in the dark. They were first detected after 1-2 hours of illumination, and then increased in amount exponentially. The kinetics of accumulation are almost identical for all the polypeptides belonging to the chlorophyll a+b protein complexes, suggesting their synthesis may be regulated by the same mechanism despite the existence of the differing posttranscriptional controls mentioned above. CP 43, a chlorophyll a antenna protein of photosystem II, appeared to follow the same time course. In contrast to some reports in the literature, small amounts of the photosystem I P700 chlorophyll o protein were detected in etiolated plants. This protein also shows a light-induced increase, showing that light plays an important role in its synthesis or degradation, even if it is not an absolute requirement for transcription and translation.Science, Faculty of
Botany, Department of
Graduate
14
Gao, Jincheng. "Canopy chlorophyll estimation with hyperspectral remote sensing". Diss., Manhattan, Kan. : Kansas State University, 2006. http://hdl.handle.net/2097/252.
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Keely, Brendan J. "Early diagenesis of chlorophyll and chlorin pigments". Thesis, University of Bristol, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329905.
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Damaraju, Sridevi. "Analysis of proteins involved in chlorophyll catabolism". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2011. http://dx.doi.org/10.18452/16322.
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Der Abbau des Chlorophyll (Chl) ist ein Prozess, der typischerweise während der Blattseneszenz und der Reifung von Früchten und Samen stattfindet. Eine Störung dieses koordinierten Prozesses unter Frostbedingungen verzögert den Chl-Abbau und ist ein grosses Hindernis bei der Herstellung von hochwertigem Rapsöl. Der Abbau von Chl zu farblosen Kataboliten erfolgt in einer Serie von enzymatischen Schritten und wird durch die Chlorophyllase begonnen (Chlase). Es wurde vorgeschlagen, dass ein wasserlösliches Chl Protein (WSCP) den Transport des Chl von der Thylakoidmembran zum Wirkort der Chlase übernimmt. Weiterhin wurde angenommen, dass die Steigerungen der Genexpressionen dieser frühen Schritte den Prozess des Chl-Abbaus beschleunigen. In der vorliegenden Arbeit werden die Auswirkungen der Überexpression der Chlase aus Citrus clementii (CcCHLASE) und von WSCP aus Blumenkohl (Cau-WSCP) in transgenen Tabakpflanzen analysiert. Dazu wurde die cDNA Sequenz der CcCHLASE in E. coli exprimiert und mittels in vitro Experimenten die Hydrolysierung von Chl durch die Chlase bestätigt. Anschließend wurden CcCHLASE exprimierende Tabakmutanten generiert und drei T1-Linien wurden unter verschiedenen Stress- und Seneszenzbedingungen untersucht. Die Chlase überexprimierenden Linien zeigten unter allen getesteten Bedingungen einen im Vergleich zum Wildtyp erhöhten Chlide a Gehalt. Trotzdem unterschied sich die Menge an Endkataboliten in diesen Mutanten nicht vom Wildtyp. Andererseits zeigten WSCP überexprimierende Linien zwar keine erhöhten Chlide a Gehalte jedoch erhöhte Protochlorophyllid-(Pchlide)-Level. Das deutet auf eine Rolle des WSCP als Speichermolekül für Chlorophyllvorstufen hin. Die photoprotektive Funktion des WSCP wurde zusätzlich in WSCP überexprimierenden Linien bestätigt. Diese zeigen im Vergleich zu Wildtyp-Tabakpflanzen auch bei hohen Lichtintensitäten von 700 – 900 µmol Photonen m-2 s-1 verringerte Gehalte an Zeaxanthin und reduzierte Peroxidaseaktivitäten.Chlorophyll (Chl) catabolism is characteristically seen during leaf senescence, fruit ripening and seed maturation. Disruption of this coordinated process under frost conditions delays Chl breakdown and is a great concern in rapeseed oil production. The present work addresses this problem by studying the effect of enhanced Chl catabolism in genetically modified tobacco plants. Chl is catabolised to colourless catabolites through a series of enzymatic reactions initiated by Chlorophyllase (Chlase). A water soluble chlorophyll protein (WSCP) has been proposed to transport Chl from thylakoid membranes to the site of action of Chlase. It was assumed that enhancing the gene expression of these early events in Chl catabolism would increase the Chl breakdown process. The present work analysed the overexpression of Chlase from Citrus clementii (CcCHLASE) and WSCP gene from cauliflower (Cau-WSCP) in modified tobacco plants. Initially, the cDNA sequence of CcCHLASE was expressed in E. coli and in vitro tests confirmed the hydrolytic activity of Chlase on Chl. Subsequently, tobacco plants overexpressing CcCHLASE were generated and three T1 lines were analysed at various stress and senescence conditions. The in vivo production of Chlorophyllide (Chlide) indicated the extent of increased Chl breakdown. The Chlase overexpressor lines showed higher Chlide a steady state levels under all tested conditions in comparison to the WT tobacco plants. However, the end catabolites did not show much difference from WT plants. On the other hand, WSCP overexpressor lines did not show any increase in Chlide a levels, but demonstrated an increased protochlorophyllide (Pchlide) levels. This suggested the role of WSCP as a storage molecule of Chl precursors. Additionally, photoprotective function of WSCP was confirmed in WSCP overexpressors, by lower zeaxanthin levels and peroxidase activity even at high light intensities of 700 – 900 µmol photons m-2 s-1 in comparison to the WT tobacco plants.
17
Binnie, Nancy Elaine Carleton University Dissertation Chemistry. "Electronic origins of monomeric and dimeric chlorophyll a as determined from wavelength selective fluorescence and raman excitation profiles". Ottawa, 1988.
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Force, Lesleigh Eileen. "Applications of the JIP-test of chlorophyll fluorescence /". [St. Lucia, Qld.], 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16307.pdf.
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Fletcher, William Wallerich. "Seasonal and interannual differences in surface chlorophyll stocks and integrated water column chlorophyll stocks in the northeastern Gulf of Mexico". Texas A&M University, 2004. http://hdl.handle.net/1969.1/2694.
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During the Northeastern Gulf of Mexico Chemical and Hydrography study (NEGOM-COH), nine oceanographic cruises were fielded during the spring, summer and fall seasons from November 1997 to August 2000. Surface chlorophyll-? fluorescence, salinity, and temperature data were logged once a minute from the R/V Gyre and subsurface chlorophyll-? fluorescence, salinity, temperature, and nutrients were profiled when the ship stopped to make stations. Each cruise occupied 94-98 stations, partitioned among 11 cross-margin transects of water depths between 10 m to 1000 m.
Overall chlorophyll-? abundance within the study area is forced by the amount of freshwater discharge. Seasonal and interannual differences are largely determined by the monthly mean streamflow for the major rivers within the NEGOM area, particularly the Mississippi River. However, an important forcing function for transport of river water to the outer continental shelf and slope is the periodic presence of anticyclonic slope eddies. Especially when these slope eddies were centered south and east of the Mississippi River delta, they entrained and so redistributed low salinity green water to a wider area within the NEGOM region than could be predicted by mean monthly streamflow alone. The mean surface chlorophyll-? concentrations, and in particular the distribution of relatively high surface chlorophyll-? concentrations off-shelf, were strongly dependent upon entrainment of freshwater by these slope eddies, especially during the three summer cruises. Interannual variability in the summertime entrainment of low salinity green water was driven by summer-to-summer differences in sea surface height (SSH) of the slope eddy(s), and in how far they extended on margin.
Satellite observations of ocean color showed that freshwater entrainment by anticyclonic eddies persisted for a temporal scale of several weeks each summer. Satellite-derived surface chlorophyll-? concentrations were positively correlated with in situ measurements of surface chlorophyll-?, with greatest agreement between satellite and ship measurements of surface chlorophyll-? at concentrations <1.5 mg/m3. Because subsurface chlorophyll-? concentrations were often elevated at depths greater than the first optical depth, satellite measurements of chlorophyll-? concentration generally underestimated integrated chlorophyll-? standing stocks within the euphotic zone.
20
Snigula, Heike. "(Bakterio-)Chlorophyll-Modifikationen zur Einlagerung in synthetische Peptide". Diss., lmu, 2003. http://nbn-resolving.de/urn:nbn:de:bvb:19-12496.
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Earl, Hugh J. "Estimating leaf photosynthesis in maize using chlorophyll fluorometry". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ31883.pdf.
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Lakish, Benjamin. "Nutrients and chlorophyll dynamics in Fort Cobb Reservoir". Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4956.
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Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 31, 2008) Includes bibliographical references.
23
Khamessan, Ali. "Chlorophyllase biocatalysis of chlorophyll in organic solvent media". Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28798.
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Cette recherche comprend l'etude de la bioacatalyse de la chlorophyllase partiellement purifiee a partir d'algue (Phaeodactylum tricornutum) dans differents milieux organiques incluant les solvants miscibles et non miscibles a l'eau et les systemes micellaires tertiaires. Les quantites optimales d'eau et de solvant, choisi en fonction de son degre d'hydrophobicite et incluant l'acetone, l'ethanol, le propanol, le butanol, le pentanol, l'hexanol, le toluene, le pentane, l'hexane, l'heptane et l'octane, necessaire a la catalyse de l'effet hydrolytique de la chlorophyllase, ont ete mesurees. Les valeurs d $V sb{ rm max}$ obtenues mesurant l'activite hydrolytique de la chlorophyllase sont plus elevees chez les solvants miscibles a l'eau (log P 0.8). L'activite hydrolytique de la chlorophyllase decroit d'approximativement 12 fois lorsque le nombre de carbone pour les alcools, passent de 2 a 5. Certains resultats a partir du FTIR ("Fourier transform infrared spectroscopy") tendent a montrer que le phytol pourrait agir comme un donneur d'electron, ainsi, si un compose nucleophilique approprie est ajoute a un syteme biphasique, la solubilite de la chlorophylle dans l'hexane augmentera et l'activite hydrolytique de la chlorophyllase augmentera. En milieu biphasique (hexane/eau), l'addition de solvants polaires tels que l'acetone, l'ethanol, et le propanol augmente l'activite de la chlorophyllase et ce seulement a certaines concentrations. La mesure optimale de l'activite hydrolytique de la chlorophyllase en milieu micellaire tertiaire (tampon/hexane/surfactant) utilisant les polysorbates et les Spans ainsi que differentes chai nes hydrophobiques comme surfactant indique que les concentrations necessaires de surfactants sont dependantes a la fois de la chai ne hydrophobique et du groupement polaire. Toutefois, l'utilisation du Span 85 s'est avere plus approprie et les valeurs de $V sb{ rm max}$ obtenues mesurant l'activite enzymatique de la chlorophyllase sont 288 fois
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Pilkington, Sarah Mary. "The regulation of chlorophyll levels in maturing kiwifruit". Thesis, University of Canterbury. School of Biological Sciences, 2012. http://hdl.handle.net/10092/7478.
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The chlorophyll degradation pathway is central to a number of plant processes including senescence and fruit ripening. However, the regulation of the chlorophyll degradation pathway enzymes is not well understood. The aim of this thesis was to elucidate the genetic mechanisms that control changes in pigment composition leading to fruit flesh yellowing in kiwifruit. Actinidia deliciosa and A. chinensis fruit, which are green and yellow, respectively, provide an opportunity to study the regulation of chlorophyll levels.
The expression of genes that code for enzymes of the chlorophyll and cytokinin metabolic pathways was measured using qRT-PCR. Candidates for chlorophyll degradation regulatory points were then characterised for functionality by transient transformation in N. benthamiana. The endogenous cytokinin levels were measured in kiwifruit and transient activation assays were carried out with the promoters of key candidate genes.
Overall, expression of the chlorophyll degradation genes was elevated in yellow fruit and expression of biosynthetic genes was higher in green fruit. The chlorophyll degradation-associated protein, STAY-GREEN2 (SGR2), was more highly expressed in yellow fruit, and transient over-expression of SGR was sufficient to drive chlorophyll degradation. Expression of isopentenyl transferase (IPT), the rate-limiting step for cytokinin biosynthesis, showed an increase towards maturity in green fruit, but not in yellow fruit. However, both fruit had similar high levels of cytokinin nucleotides and free bases. A gene coding for O-glucosylation was also highly expressed in green fruit. Green fruit contained higher levels of cytokinin O-glucosides and ribosides towards maturity, suggesting differences in cytokinin signalling, which could lead to regulation of chlorophyll levels via activation of the SGR promoter by transcription factors.
It is likely that the chlorophyll degradation pathway and cytokinin metabolism are linked. The differential expression of cytokinin response regulators could lead to differential regulation of cytokinin levels in the fruit of the two species, and possibly differential regulation of the chlorophyll degradation pathway. Progress towards elucidation of the control of chlorophyll levels provides knowledge of this key process in kiwifruit and potentially gene-based markers for breeding new kiwifruit cultivars.
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Onabid, Mathias Akong. "Improved ocean chlorophyll estimates from remote sensed data". Thesis, University of Glasgow, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438091.
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Naylor, Christopher Charles. "Early oxidative transformation of chlorophyll in contemporary environments". Thesis, University of York, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361987.
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Whyte, Barry James. "Characterisation of the terminal stages of chlorophyll biosynthesis". Thesis, University of Bristol, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.346444.
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MATOS, ANA GABRIELA BARBOSA. "CHLOROPHYLL A DETERMINATION IN MARINE WATER BY FLUORESCENCE". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2001. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=2198@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORA clorofila a é um composto-chave no processo de absorção e aproveitamento da energia luminosa na fotossíntese. Monitorar a fluorescência da clorofila a para obter informações do aparato fotossintético de produção de energia é uma abordagem atraente porque a fluorescência á percebida externamente às células, podendo ser detectada sem destruir sua fonte. Estudos anteriores realizados pelo Laboratório de Hidrobiologia (UFRJ) e pelo Laboratório de Monitoramento Ambiental Remoto (LabMAR) (PUC-Rio) em águas marinhas indicaram a existência de uma relação linear entre os valores absolutos obtidos pelo Laboratório de Hidrobiologia para a concentração da clorofila a e os valores relativos obtidos pelo LabMAR para a sua fluorescência. Este resultado motivou os dois laboratórios a obter valores absolutos para a concentração da clorofila a em águas marinhas, a partir da medida de sua fluorescência, com a maior confiabilidade possível para, então, relacioná-los aos valores relativos fornecidos pelo LIDAR-PUC. Neste sentido, a implantação de um programa de controle de qualidade no Laboratório de Hidrobiologia indicou que este laboratório encontra-se em condições de obter valores confiáveis para a concentração da clorofila a em amostras de águas marinhas através da fluorimetria. No entanto, uma avaliação rigorosa da relação entre a intensidade da fluorescência da clorofila a (normalizada pela intensidade da emissão do espalhamento Raman da água) e o respectivo valor confiável para a concentração da clorofila a se faz necessária.
Chlorophyll a is a key-compound in the process of light absorption in the photosynthesis. Monitor the chlorophyll a fluorescence to obtain information about the photosynthetic apparatus of energy production is attractive because the chlorophyll a fluorescence could be detected without destruction of the source. Studies performed by the Laboratório de Hidrobiologia (UFRJ) and by the Laboratório de Monitoramento Ambiental Remoto (LabMAR) (PUC-Rio) in marine water samples indicated a linear relation between the absolute values obtained by the former for the chlorophyll a concentration and the relative values obtained by the latter for the chlorophyll a fluorescence. This result motivated both laboratories to obtain absolute values for the chlorophyll a concentration, in marine water samples, as confident as possible and, then, relate these values to the relative values generated by the LIDAR-PUC. In this way, the introduction of a quality control program in the Laboratório de Hidrobiologia indicated that this laboratory is able to analyse marine water samples and to obtain confident values for the chlorophyll a concentration by fluorimetry. However, a more rigorous evaluation of the relation between the chlorophyll a fluorescence and the respective confident value for the chlorophyll a concentration is still necessary.
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Chen, Guangyu. "The aerobic cyclase involved in (bacterio)chlorophyll biosynthesis". Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/15949/.
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Proctor, Matthew Stephen. "Characterisation of chlorophyll synthases from cyanobacteria and plants". Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/22964/.
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During the process of photosynthesis, oxygenic photosynthetic organisms utilise chlorophyll (Chl) molecules, spatially organised within membrane associated protein complexes called photosystems, to capture light from the sun and convert it into chemical energy. Chls are tetrapyrrole molecules featuring a fifth ring, a central Mg2+ ion and a hydrophobic phytyl tail. The integral membrane protein chlorophyll synthase (ChlG) catalyses the addition of the tail to the pyrrole ring. In the model photosynthetic cyanobacteria Synechocystis, ChlG forms a protein-pigment complex with high-light inducible proteins C and D (HliC/HliD), photosystem II assembly factor Ycf39, the YidC/Alb3 insertase and pigments zeaxanthin, myxoxanthophyll, β-carotene and Chl. This complex is postulated to act at the interface between Chl biosynthesis and photosystem assembly, coordinating co-translational insertion of de novo Chl molecules into Chl-binding proteins in a poorly understood process. To gain an insight into the ubiquity of the ChlG complex in higher photosynthetic organisms, ChlG genes from a plant and algae were FLAG-tagged and heterologously expressed in Synechocystis. The eukaryotic ChlG homologues could complement the function of the native bacterial protein but did not associate with HliD or Ycf39, maintaining an association only with YidC. This indicates that the ChlG-YidC/Alb3 association may be evolutionarily conserved in algae and higher plants. Abolishing the synthesis of zeaxanthin and myxoxanthophyll in Synechocystis prevented association of HliD and Ycf39 with ChlG, indicating that these carotenoids mediate formation of the ChlG complex. Selective abolishment of myxoxanthophyll restored binding of these proteins, suggesting that zeaxanthin alone can facilitate the ChlG-HliD-Ycf39 interaction. Structural investigation by chemical cross-linking revealed sites of interaction between members of the ChlG complex. These were found to be confined to the cytoplasm. The N-terminal domain of ChlG was the only region of the enzyme found to interact with its partner proteins. The results enabled the generation of a model of the ChlG complex. The N-terminus of ChlG was sequentially truncated to investigate the importance of this domain to formation of the ChlG complex. Four truncations were made, removing 11, 23, 32 and 39 residues from the N-terminus, up until the start of the first predicted transmembrane helix. While the binding of YidC, HliD and Ycf39 was not impeded in any case, the enzyme activity of ChlG reduced as the truncations became larger. ChlGs lacking 32 or more residues were unable to complement the function of the native enzyme in vivo and showed significantly reduced activity in vitro. The results indicate that the N-terminal domain of ChlG is important for facilitating its catalytic activity. A method for the rapid generation and in vitro testing of point mutations to the function of Arabidopsis ChlG was developed. This involved optimising production of ChlG in E. coli in addition to developing a method for producing the enzymes substrate, chlorophyllide. A ChlG model was generated using the crystal structure of a related protein, UbiA, as a template. The optimised methods were used to generate six point mutations, predicted from the model and sequence alignments of ChlG with UbiA to be important for enzyme activity or substrate binding. Three of the mutants were devoid of activity, demonstrating the importance of these residues to enzyme function.
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Wilson, Samuel Johnson. "Studies of Chlorophyll Dynamics using Moored Irradiance Sensors". Thesis, University of California, San Diego, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10238822.
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Understanding oceanic chlorophyll dynamics requires new measurement methods and novel analyses. Moored irradiance sensors provide long time series of diffuse attenuation, and through a technique developed here, can provide estimates of average chlorophyll concentration between the sensors. This technique is applied to the California Current Ecosystem moorings, where simultaneous current measurements coupled with the chlorophyll time series describe chlorophyll transport. Cross-shore transport events occur on timescales longer than 25 days in the offshore site, and account for offshore chlorophyll transport of 31.20 g/(day) per meter of coastline. In the near shore site, successive upwelling events transport large amounts of chlorophyll offshore, while single upwelling events do not. In total, events account for 94.80 g/(day) offshore chlorophyll transport per meter of coastline at this site. The method is then applied to recover 9 years of 0-9m chlorophyll concentration estimates in the Northwestern Mediterranean Sea. This region is dominated by a spring chlorophyll bloom, and the chlorophyll model used describes interannual variability in the initiation of this event by 25 days or more. During the bloom, hiatuses can occur where the 0-9m chlorophyll concentration decreases due to mixing, and they are often associated with Spring cooling events. The date of the last cooling event in January to April is a significant determinant of the delay in the 0-9m signature of the Spring Chlorophyll Bloom.
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Couto, Cristina Efimovna do. "Chlorophyll and green color stabilization on vegetable homogenates". Master's thesis, ISA-UL, 2016. http://hdl.handle.net/10400.5/12924.
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Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia - ULSeveral factors influence chlorophyll stability in foods and beverages. This study aims to determine the influence of raw material, heat treatment, pH and food additives on chlorophyll content and color stability of vegetable homogenates. Fully expanded spinach, parsley, broccoli, and lettuce leaves were harvested and immediately processed. Leaf (10%) homogenates were bottled, heat-treated at 90 ºC for 60s, cooled and stored at 20 ºC. Chlorophylls a and b were measured before and after pasteurization, and during shelf-life. Color was assessed with a colorimeter. Broccoli and parsley, spinach and lettuce had an initial hue angles of 132.8°, 129.0° and 109.8°, respectively. Chlorophyll content was higher in broccoli (171.4 μg mL-1) and lower in lettuce (44.4 μg mL-1). Hue and chlorophyll content decreased in all homogenates during pasteurization. At pH 8.5 the addition of sodium bicarbonate and zinc chloride had a positive effect on retention of chlorophyll and hue of spinach, parsley and broccoli homogenates, with hue increases of 8% in samples treated with sodium bicarbonate and 9% in those with zinc chloride. At pH 4.5 hue decreased 18% in all samples, with accompanying color shift to olive green. During shelf-life, hue and chlorophyll content was better maintained at higher pH in all samples, with higher values registered for broccoli samples, irrespective of additive. Pre-harvest zinc application in lettuce had a positive effect on color of pasteurized samples, with no significant effect in chlorophyll content. However, there was visual evidence of color retention for these samples. Total chlorophylls decreased 19% in all lettuce samples due to heat treatment. While hue, chlorophyll content and visual color were better maintained in samples with pre-harvest treatments during shelflife, the addition of zinc did not affect these parameters. A significant relationship between sample hue and total chlorophyll content was found, for all vegetable samples in study
N/A
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Cendrero, Mateo Maria del Pilar. "Chlorophyll Fluorescence Response to Water and Nitrogen Deficit". Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/312504.
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The increasing food demand as well as the need to predict the impact of warming climate on vegetation makes it critical to find the best tools to assess crop production and carbon dioxide (CO₂) exchange between the land and atmosphere. Photosynthesis is a good indicator of crop production and CO₂ exchange. Chlorophyll fluorescence (ChF) is directly related to photosynthesis. ChF can be measured at leaf-scale using active techniques and at field-scales using passive techniques. The measurement principles of both techniques are different. In this study, three overarching questions about ChF were addressed: Q1) How water, nutrient and ambient light conditions determine the relationships between photosynthesis and ChF? Which is the optimum irradiance level for detecting water and nutrient deficit conditions with ChF?; Q2) which are the limits within which active and passive techniques are comparable?; and Q3) What is the seasonal relationship between photosynthesis and ChF when nitrogen is the limiting factor? To address these questions, two main experiments were conducted: Exp1) Concurrent photosynthesis and ChF light-response curves were measured in camelina and wheat plants growing under (i) intermediate-light and (ii) high-light conditions respectively. Plant stress was induced by (i) withdrawing water, and (ii) applying different nitrogen levels; and Exp2) coincident active and passive ChF measurements were made in a wheat field under different nitrogen treatments. The results indicated ChF has a direct relationship with photosynthesis when water or nitrogen drives the relationship. This study demonstrates that the light level at which plants were grown was optimum for detecting water and nutrient deficit with ChF. Also, the results showed that for leaf-average-values, active measurements can be used to better understand the daily and seasonal behavior of passive ChF. Further, the seasonal relation between photosynthesis and ChF with nitrogen stress was not a simple linear function. Our study showed that at times in the season when nitrogen was sufficient and photosynthesis was highest, ChF decreased because these two processes compete for available energy. These results demonstrated that ChF is a reliable indicator of crop stress and has great potential for better understand the CO₂ exchange between the land and atmosphere.
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Thibodeau, Daniele L. Carleton University Dissertation Chemistry. "Resonance raman excitation study of monomeric and dimeric chlorophyll a in solution". Ottawa, 1988.
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Srirangam, Siva. "Retrieval of Oceanic and Physiological Parameters Using Computational Intelligence". Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/SrirangamS2004.pdf.
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Liu, Cheng-Chien. "Using SeaWiFS ocean colour data to test a plankton ecosystem model". Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343733.
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Grunenfelder, Laura. "Physiological studies of light-induced greening in fresh market potatoes". Online access for everyone, 2005. http://www.dissertations.wsu.edu/Thesis/Spring2005/L%5FGrunenfelder%5F050405.pdf.
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Sancak, Serkan. "Reconstruction Of Seawifs Chlorophyll Data For The Black Sea". Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613518/index.pdf.
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SeaWiFS was collecting ocean color data since 1997. This means chlorophyll-a data for more than ten years. Since, SeaWiFS Chl-a data is validated for Black Sea this data set can be used for analysis. Nevertheless, the data is not gap free due to cloud effect. One of the main objectives of this
work is to obtain a gap free, complete Chl-a data set for the Black Sea. For this purpose DINEOF method will be used.
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Schmid, Heidi. "Biochemische Untersuchungen an der Chlorophyll Synthase aus Avena sativa". Diss., lmu, 2003. http://nbn-resolving.de/urn:nbn:de:bvb:19-11387.
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Gögüs, Emrah [Verfasser]. "Studien zur Totalsynthese von enantiomerenreinem Chlorophyll a / Emrah Gögüs". München : Verlag Dr. Hut, 2014. http://d-nb.info/1064559859/34.
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Hollingshead, Sarah Louise. "Investigating protein-protein interactions in the chlorophyll biosynthesis pathway". Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/6488/.
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The production of chemical energy from light energy is arguably the most important reaction known, which makes photosynthesis one of the most important processes on Earth. Nearly all life depends on the energy derived from light, and it is this process that supports Earths oxygenated atmosphere. Photosynthesis is initiated by the absorption of light, which is performed by specialised pigment molecules known as the chlorophylls. These are highly specialised pigment molecules that belong to the tetrapyrrole family, which also includes vitamin B12, sirohaem and haem. Chlorophyll is synthesised via a series of chemical reactions collectively known as chlorophyll biosynthesis. Whilst the majority of enzymes required for chlorophyll biosynthesis are known and have, to some extent, been characterised, one enzyme, the magnesium protoporphyrin IX monomethylester cyclase (cyclase), remains an enigma. This enzyme catalyses the formation of the 5th isocyclic ring, altering the colour of the tetrapyrrole molecule from red to green. Despite being known for over 60 years, only one subunit of the cyclase has been identified. This is the catalytic or AcsF subunit, which contains a distinctive di-iron motif and is absolutely conserved across all known oxygenic photosynthetic organisms. One of the focuses of this work was to identify other subunits of the cyclase. This led to the discovery of Ycf54, a protein that is highly conserved among oxygenic photosynthetic organisms, which is essential for chlorophyll accumulation in Synechocystis sp. PCC6803. The latter half of this thesis focuses on investigating the structural and functional characteristics of Synechocystis Ycf54; a protein that had previously not been investigated. This work lead the identification of three residues in Ycf54 (D39, F40 and R82), which are required for protochlorophyllide synthesis and chlorophyll formation in Synechocystis, and the observation that these residues are all required for Ycf54 to interact with the catalytic (AcsF) subunit of the cyclase. Additionally, the crystal structure of wild type Synechocystis Ycf54 to a resolution of 1.2 Å, and the structures of two Ycf54 mutants (A9G and R82A), which have an in vivo phenotype were obtained using molecular replacement. Furthermore this work presents the first investigations into the previously unknown protein Slr0483 in Synechocystis. This protein contains the conserved C-terminal membrane anchoring CAAD (Cyanobacterial Aminoacyl-tRNA synthetases Appended Domain) domain and is found in all of the oxygenic photosynthetic organisms investigated. The experiments reported in this thesis show that Slr0483 is essential for photosystem stability and accumulation in Synechocystis and that this protein interacts with the chlorophyll biosynthesis enzymes protoporphyrin IX oxidase, protoporphyrin IX methyltransferase, the cyclase subunit Sll1214 and the geranylgeranyl reductase ChlP, as well as the haem biosynthesis enzyme ferrochelatase. Leading to the hypothesis that Slr0483 may serve as a membrane anchor, localising the enzymes required for chlorophyll and haem biosynthesis, to the sites where these tetrapyrroles are required in the thylakoid membrane (i.e. next to the sites of photosystem and cytochrome assembly).
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Marshall, C. Tara. "Seasonal patterns in chlorophyll-a concentrations for temperate lakes". Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66186.
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Almond, Samuel Francis. "Validation and application of the MERIS Terrestrial Chlorophyll Index". Thesis, Bournemouth University, 2009. http://eprints.bournemouth.ac.uk/16208/.
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Climate is one of the key variables driving ecosystems at local to global scales. How and to what extent vegetation responds to climate variability is a challenging topic for global change analysis. Earth observation provides an opportunity to study temporal ecosystem dynamics, providing much needed information about the response of vegetation to environmental and climatic change at local to global scales. The European Space Agency (ESA) uses data recorded by the Medium Resolution Imaging Spectrometer (MERlS) in red I near infrared spectral bands to produce an operational product called the MERlS Terrestrial Chlorophyll Index (MTCI). The MTCI is related to the position of the red edge in vegetation spectra and can be used to estimate the chlorophyll content of vegetation. The MTCI therefore provides a powerful product to monitor phenology, stress and productivity. The MTCI needs full validation if it is to be embraced by the user community who require precise and consistent, spatial and temporal comparisons of vegetation condition. This research details experimental investigations into variables that may influence the relationship between the MTCI and vegetation chlorophyll content, namely soil background and sensor view angle, vegetation type and spatial scale. Validation campaigns in the New Forest and at Brooms Barn agricultural study site reinforced the strong correlation between chlorophyll content and MTCI that was evident from laboratory spectroscopy investigations, demonstrating the suitability of the MTCI as a surrogate for field chlorophyll content measurements independent of cover type. However, this relationship was significantly weakened where the leaf area index (LAI) was low, indicating that the MTCI is sensitive to the effects of soil background. In the light of such conclusions, this project then assessed the MTCI as a tool to monitor changes in ecosystem phenology as a function of climatic variability, and the suitability of the MTCI as a surrogate measure of photosynthetic light use efficiency, to model ecosystem gross primary productivity (GPP) at various sites in North America with contrasting vegetation types. Changes in MTCI throughout the growing season demonstrated the potential of the MTCI to estimate vegetation dynamics, characterising the temporal characteristics in both phenology and gross primary productivity.
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Wentworth, Mark. "Quenching of chlorophyll fluorescence in plant light-harvesting complexes". Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340168.
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Ledendal, Marie. "Chromatic chlorophyll : Conceptual hospital textiles with chromatic Smart Materials". Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19626.
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THIS PROJECT AIMS TO look at how Smart Textiles can change today’s view and useof the interiors of the healthcare environment, through conceptual examples of the usabilityof the Photochromics and Thermochromics working as an information bridge for moreisolated patients. The thesis has a practical experimental approach and points out some of thechromatic materials possibilities in relation to present research of the two chromatic materials.The thesis discusses the relation between healing environment and the importance of aesthetics,with a purpose to meet Emotional and Social needs of feeling “alive”, “well” and“included”. Research indicate that nature has a calming affect on patients, therefore flowersand leaves have been inspiration for the expression of the textiles. The colour changecreates a subtle communicative bridge between patient and movement in the hospital - “theRhythm of the House” and the outdoor -“the Rhythm of the Sun”. The conceptual proposalpresents a design solution where the colour changeability stands for a communicativelevel, as well as a decorative and a dynamic level. The textile samples communicate thevisual and hepatic expression, as well as the integration of the electronics. The scenariofor the thesis is set to the 2015-20, due to reasonability for Smart Textiles to be developedto be used as interior textile products for the healthcare environment.
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Ryan-Keogh, Thomas J. "Understanding the role of chlorophyll fluorescence in nutrient stress". Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/362003/.
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Phytoplankton exert a dominant influence on the biogeochemical cycling of the oceans, but iron limitation in this dynamic environment can exert a control on photosynthesis. Phytoplankton evolved coping mechanisms to overcome and alleviate the effects of iron limitation. One mechanism is the alteration of the thylakoid membrane and the expression of chlorophyll-binding proteins, which can alter the variable chlorophyll fluorescence signal. Firstly, a study of the chlorophyll-binding iron-stress induced protein, IsiA, in Synechocystis PCC 6803 revealed a 60% increase under iron limitation, in agreement with the theoretical increase. On progressive iron-stress IsiA continued to accumulate without a concomitant increase in _PSI, while Fv/Fm, a measure of photochemical efficiency, continued to decrease. Secondly an oceanographic study to the high latitude North Atlantic in which chlorophyll fluorescence kinetics were used to measure the response to iron addition of in situ phytoplankton populations. The difference in the Fv/Fm between nutrient amended and control treatments (_(Fv/Fm)) was used as a measure of the relative degree of iron stress. The combined observations of both longterm (> 24 h) and short-term (24 h) indicated variability in the seasonal cycle of iron stress, with phytoplankton iron stress developing during the transition from prebloom to peak bloom conditions. Thirdly, similar physiological characteristics were also observed in an oceanographic study in the Ross Sea. The results further confirmed the highly variable response across temporal and spatial scales, but also within different phytoplankton groups. Consistent across all three studies is the reduction in Fv/Fm as the result of an elevated Fo signal, representing potentially unbound chlorophyll-binding proteins. These unbound chorophyll-binding proteins can dominate the total cellular chlorophyll, at least in culture, and reflect a large resource investment. These proteins may provide a rapid source of chlorophyll upon iron resupply. Irrespective of the underlying causes of unbound chlorophyll-binding proteins, the potential large scale expression of such complexes provides a powerful diagnostic tool with which to investigate iron stress in situ.
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Gibbs, Jennifer S. (Jennifer Sokolovic). "Environmental Factors Influencing Chlorophyll-a Concentrations in Lake Texoma". Thesis, University of North Texas, 1998. https://digital.library.unt.edu/ark:/67531/metadc278088/.
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An analysis of algal biomass measured by chlorophyll-a concentration in Lake Texoma was performed as a part of a monitoring program to develop baseline environmental data in order to detect the potential effects of engineered changes in chloride concentrations in the reservoir. This portion of the research project focused on two main research objectives. The first objective was evaluating the effect of sampling strategy on the ability to adequately reflect standing crop estimates and trends in algal biomass. Two sampling regimes utilizing replication of three versus ten samples were applied and then analyzed using a minimum detectable difference algorithm to determine the necessary magnitude of replication to represent the variation in the metric. Chlorophyll-a distribution was analyzed for zonation patterns expected in a river-run reservoir to establish the importance of representative sampling of river, transition and main lake zones of the reservoir for management decisions and trophic characterization.
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Jiang, Lei [Verfasser]. "Folding and assembly of the major light-harvesting chlorophyll protein (LHCII) of the photosynthetic apparatus in plants : the chlorophyll a - containing intermediate / Lei Jiang". Mainz : Universitätsbibliothek der Johannes Gutenberg-Universität Mainz, 2016. http://d-nb.info/122529634X/34.
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DI, BIAGIO VALERIA. "A method to characterize the statistical extremes in marine biogeochemistry: the case of the Mediterranean chlorophyll". Doctoral thesis, Università degli Studi di Trieste, 2017. http://hdl.handle.net/11368/2908150.
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Biogeochemical extreme events are analysed for the special case of the surface chlorophyll in the Mediterranean open sea. The extremes are defined statistically as values over the 99th percentile threshold that are connected in space and time.
A multidecadal simulation with daily output (1979-2012) was run to collect the statistics needed to carry out the study. The online coupled hydrodynamic-biogeochemical (MITgcm-BFM) model has a spatial resolution of 1/12°, with 75 vertical levels. The model was corroborated with available observations and other validated models.
To account for the heterogeneity of the chlorophyll features and dynamics across the Mediterranean area, the definition of the extremes as peaks over the threshold was initially applied at each grid point and then refined to include in one extreme event all the points near in space with extremes at the same time. The macro-events were then characterized by a set of indexes, related to their spatio-temporal localisation, shape and impact on the local marine ecosystem due to their supply of high and/or anomalous biomass production. Following, the macro-events occurred in the Mediterranean area in the winter-spring months of the 1994-2012 period were described and classified using the introduced set of indexes.
Overall, the macro-events occurred in each year during the winter months, especially in the northern part of the Mediterranean Sea. They have a wide spectrum of possible shapes, mainly corresponding to a duration shorter than 20 days and a radius contained within the larger Mediterranean mesoscale (200 km).
The most persistent macro-events (uniformity index higher than 60%) are relatively small and short within the total spectrum, with an inverse proportionality between area and duration.
The most severe macro-events (mean severity higher than 1.1 kgChl/km2/day in the first meter of depth) have intermediate area and duration; generally they are not very persistent, but sometimes they are very anomalous (anomaly higher than 15%).
The most anomalous macro-events have typically medium or long duration (up to 84 days) and they can be also very large (up to the whole sub-basin scale), but not very persistent.
In agreement with literature, no significant trends are observed in the macro-events indexes on the basin-scale.
Some subdomains were analysed in detail: the North Western Mediterranean Sea (NWM), the Ionian Sea (ION), the South Adriatic Sea (ADS) and the Levantine Sea (LEV). The decreasing eastward gradient of the mean severity across the subdomains reflects the well known gradients of the mean surface chlorophyll. More than 70% of the macro-events of chlorophyll occurred in NWM and ADS are classified as events of high severity and high anomaly with respect to the medians of the distributions of the mean severity and anomaly on the whole domain. Overall, the most severe macro-events are in NWM. ADS is the subdomain with the most persistent macro-events, possibly ascribed to the spatial constraints of the topography and of the circulation structure. In ION and LEV more than the 50% of macro-events show low values of both indexes, even if hot spots of macro-events heavily affecting the ecosystem can be observed in the North Ionian Sea, close to the southern coasts of Sicily and in the Rhodes Gyre regions.
Focusing on some representative examples of macro-events further investigated, we observed that the model is able to reproduce the main features of timing and location of the chlorophyll patterns observed by remote sensing and that the physical forcing anomalies with respect to climatology appear to play the major role as trigger of the macro-events. Finally, the selected macro-events are characterized by phytoplankton subgroups (BFM parametrization of picophytoplankton, flagellates, diatoms, large phytoplankton) that evolve in space and time in different ways in the subdomains.
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Martin, Sophie. "Photoelectrochemistry of immobilised photosynthetic components: From chlorophyll to intact chloroplasts". Thesis, University of Warwick, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487960.
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This thesis aims to explore the use of scanning electrochemical microscopy (SECM) to investigate a range of processes, in particular fundamental electron transfer processes, connected to photosynthesis. These studies focus on several model systems ranging from LB films of chI a to intact chloroplasts. Electrochemical and scanned probe microscopy (SPM) techniques will be invaluable for monitoring these electron transfer processes and the structure - activity relationships in the systems of interest. A study of the different methods of chlorophyll film formation on solid supports and characterisation of these films with regard to surface coverage and film thicknesses has been explored with a range of techniques. Dropcast, spincast and LB films are investigated using UV-visible spectroscopy and AFM in order to elucidate the most appropriate chlorophyll film formation techniques for use in the later studies of this thesis. SECM has combined with an inverted microscope setup to investigate electron transfer in thin films of chlorophyll, with the aim of correlating the photoelectrochemical activity of the chlorophyll layer with the spatial organisation of the film. Using LB techniques, monolayers and multilayer films of chi a have been prepared on solid inert supports. It is clarified that electron transfer occurs from photo-excited chlorophyll to reduce oxygen. This is observed using SEeM, to electrochemically follow the transient change in oxygen concentration close to chlorophyll films upon illumination. The data obtained have been simulated using a commercial software package and used to determine kinetic parameters for this electron transfer process. This work is extended by considering the effects of electron transport in chI a molecules when deposited onto conducting electrode surfaces, compared to inert glass surfaces. These studies present some contradictory results to those previously published in literature and these findings have been discussed. ' The photosynthetic activity and surface structure of chloroplast and 'thylakoid membranes using SPM techniques and CLSM has been investigated. Factors such as illumination conditions, O2 evolution and reactions with different redox mediators will be studied to probe key steps in the electron transport chain reaction. Finally, confocal microscopy has been combined with SECM to study lateral proton diffusion at different phospholipid monolayers under a range of surface pressures. Therefore, investigating key diffusional processes as a model for those processes occurring at biological membranes.