An investigation into the functional role of the D1:1 and D1:2 polypeptides in photosystem II in cyanobacteria : the effect of changing PSI/PSII ratio on photoinhibition in Synechococcus sp. PCC7942 /

The cyanobacterium Synechococcus sp. PCC 7942 (Anacystis nidulans R2) adjusts its photosynthetic function by changing one of the polypeptides of photosystem II. This polypeptide, called Dl, is found in two forms in Synechococcus sp. PCC 7942. Changing the growth light conditions by increasing the light intensity to higher levels results in replacement of the original form of D 1 polypeptide, D 1: 1, with another form, D 1 :2. We investigated the role of these two polypeptides in two mutant strains, R2S2C3 (only Dl:l present) and R2Kl (only Dl:2 present) In cells with either high or low PSI/PSII. R2S2C3 cells had a lower amplitude for 77 K fluorescence emission at 695 nm than R2Kl cells. Picosecond fluorescence decay kinetics showed that R2S2C3 cells had shorter lifetimes than R2Kl cells. The lower yields and shorter lifetimes observed in the D 1 and Dl:2 containing cells. containing cells suggest that the presence of D 1: 1 results in more photochemical or non-photochemical quenching of excitation energy In PSII. One of the most likely mechanisms for the increased quenching in R2S2C3 cells could be an increased efficiency in the transfer of excitation energy from PSII to PSI. However, photophysical studies including 77 K fluorescence measurements and picosecond time resolved decay kinetics comparing low and high PSI/PSII cells did not support the hypothesis that D 1: 1 facilitates the dissipation of excess energy by energy transfer from PSII to PSI. In addition physiological studies of oxygen evolution measurements after photoinhibition treatments showed that the two mutant cells had no difference in their susceptibility to photoinhibition with either high PSI/PSII ratio or low PSI/PSII ratio. Again suggesting that, the energy transfer efficiency from PSII to PSI is likely not a factor in the differences between Dl:l and Dl:2 containing cells.

Orientation of Non-Native 2-Monosubstituted and 2,3-Disubstituted 1,4-Naphthoquinones in the A1 binding site of PSI and the effect on the rate of electron transfer : an electron paramagnetic resonance spectroscopy study

The proce-ss ofoxygenic photosynthesis is vital to life on Earth. the central event in photosynthesis is light induced electron transfer that converts light into energy for growth. Ofparticular significance is the membrane bound multisubunit protein known as Photosystem I (PSI). PSI is a reaction centre that is responsible for the transfer of electrons across the membrane to reduce NADP+ to NADPH. The recent publication ofa high resolution X-ray structure of PSI has shown new information about the structure, in particular the electron transfer cofactors, which allows us to study it in more detail. In PSI, the secondary acceptor is crucial for forward electron transfer. In this thesis, the effect of removing the native acceptor phylloquinone and replacing it with a series of structurally related quinones was investigated via transient electron paramagnetic resonance (EPR) experiments. The orientation of non native quinones in the binding site and their ability to function in the electron transfer process was determined. It was found that PSI will readily accept alkyl naphthoquinones and anthraquinone. Q band EPR experiments revealed that the non-native quinones are incorporated into the binding site with the same orientation of the headgroup as in the native system. X band EPR spectra and deuteration experiments indicate that monosubstituted naphthoquinones are bound to the Al site with their side group in the position occupied by the methyl group in native PSI (meta to the hydrogen bonded carbonyl oxygen). X band EPR experiments show that 2, 3- disubstituted methyl naphthoquinones are also incorporated into the Al site in the same orientation as phylloquinone, even with the presence of a halogen- or sulfur-containing side chain in the position normally occupied by the phytyl tail ofphylloquinone. The exception to this is 2-bromo-3-methyl --.- _. -. - -- - - 4 _._ _ _ - _ _ naphthoquinone which has a poorly resolved spectrum, making determination of the orientation difficuh. All of the non-native quinones studied act as efficient electron acceptors. However, forward electron transfer past the quinone could only be demonstrated for anthraquinone, which has a more negative midpoint potential than phylloquinone. In the case of anthraquinone, an increased rate of forward electron transfer compared to native PSI was found. From these results we can conclude that the rate ofelectron transfer from Al to Fx in native PSI lies in the normal region ofthe Marcus Curve.

An examination of outdoor experience in the development of character in young adults with Type 1 Diabetes

Connected in Motion is a not for profit organization serving young adults with Type 1 diabetes. The organization hosted outdoor and experiential Type 1 diabetes education programs in January of2009 and 2010. The weekends provided non-clinical alternative Type 1 diabetes education to the underserved population of young adults within Canada. Six women living with Type I diabetes and between the ages of 22 and 30 participated in the Winter Slipstream weekends participated in this phenomenological research study. Through semi-structured interviews and artifact-elicitation interviews, ,{ the lived experiences of the participants were examined. Data analysis indicated that the sense of community created through outdoor programming and experiential education for young adults with Type I diabetes stimulated the development of self-efficacy and participant-perceived improvement in Type 1 diabetes self-management. There was no indication that outdoor and experiential Type I diabetes education had any impact on the development of autonomy among participants. Recommendations are made to encourage the successful implementation of further alternative (non-clinical) Type 1 diabetes education programs for young adults living with Type 1 diabetes.

An estimate of work done by Messrs. Brown and McDonell, contractors on sections 1, 2 and 3 ending at St. Catharines for the months of April and May 1855

Scrap of paper that has been burned almost completely. Only the header of the document is intact. It is an estimate of work done by Messrs. Brown and McDonell, contractors on sections 1, 2 and 3 ending at St. Catharines for the months of April and May 1855.

Cardiovascular and sensory abnormalities in a rat model of insulin resistance : beneficial effect of an antioxidant and an angiotensin-1 converting enzyme inhibitor

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Coherent Stranski-Krastanov growth in 1+1 dimensions with anharmonic interactions: An equilibrium study

The formation of coherently strained three-dimensional (3D) islands on top of the wetting layer in the Stranski-Krastanov mode of growth is considered in a model in 1 + 1 dimensions accounting for the anharmonicity and nonconvexity of the real interatomic forces. It is shown that coherent 3D islands can be expected to form in compressed rather than expanded overlayers beyond a critical lattice misfit. In expanded overlayers the classical Stranski-Krastanov growth is expected to occur because the misfit dislocations can become energetically favored at smaller island sizes. The thermodynamic reason for coherent 3D islanding is incomplete wetting owing to the weaker adhesion of the edge atoms. Monolayer height islands with a critical size appear as necessary precursors of the 3D islands. This explains the experimentally observed narrow size distribution of the 3D islands. The 2D-3D transformation takes place by consecutive rearrangements of mono- to bilayer, bi- to trilayer islands, etc., after the corresponding critical sizes have been exceeded. The rearrangements are initiated by nucleation events, each one needing to overcome a lower energetic barrier than the one before. The model is in good qualitative agreement with available experimental observations.

Potential application of β-1, 3 glucanase from an environmental isolate of Pseudomonas aeruginosa MCCB 123 in fungal DNA extraction

Pseudomonas aeruginosa MCCB 123 was grown in a synthetic medium for β-1,3 glucanase production. From the culture filtrate, β-1,3 glucanase was purified with a molecular mass of 45 kDa. The enzyme was a metallozyme as its β-1,3 glucanase activity got inhibited by the metal chelator EDTA. Optimum pH and temperature for β-1,3 glucanase activity on laminarin was found to be 7 and 50 °C respectively. The MCCB 123 β-1,3 glucanase was found to have good lytic action on a wide range of fungal isolates, and hence its application in fungal DNA extraction was evaluated. β-1,3 glucanase purified from the culture supernatant of P. aeruginosa MCCB 123 could be used for the extraction of fungal DNA without the addition of any other reagents generally used. Optimum pH and temperature of enzyme for fungal DNA extraction was found to be 7 and 65 °C respectively. This is the first report on β-1,3 glucanase employed in fungal DNA extraction

An algebraic proof of Iitaka's conjecture C2,1

We give a proof of Iitaka's conjecture C2,1 using only elementary methods from algebraic geometry.

CD-Systems of Stateless Deterministic R(1)-Automata Governed by an External Pushdown Store

We study cooperating distributed systems (CD-systems) of stateless deterministic restarting automata with window size 1 that are governed by an external pushdown store. In this way we obtain an automata-theoretical characterization for the class of context-free trace languages.

Benachteiligte Jugendliche beim Übergang an der 1. Schwelle

Im Mittelpunkt dieser Diplomarbeit stehen Jugendliche, mit schlechten Ausbildungschancen, beim Übergang von der Schule in den Beruf. Hierbei liegt ein Schwerpunkt zunächst auf dem Übergangssystem, in das insbesondere benachteiligte Jugendliche nach den allgemeinbildendenden Schulen einmünden. Weil für diese Zielgruppe das Übergangssystem auch eine „Warteschleife“ bedeuten kann, werden im Rahmen dieser Arbeit neuere Fördermaßnahmen untersucht, die eine intensivere Betreuung dieser Zielgruppe anstreben. Dies ist zum einen das hessische Konzept der SchuB- Klassen, welches sich durch seine besondere Praxisnähe zu den Betrieben auszeichnet und zum anderen die bundesweit eingeführten Kompetenzagenturen, die eine individuelle und intensive Förderung der Jugendlichen ermöglicht. Durch die durchgeführten Interviewgespräche mit Lehrern und Case- Managern, die mit den betroffenen Jugendlichen arbeiten, wurde eine qualitative Untersuchung dieser Fördermaßnahmen vorgenommen.

El tratamiento del art??culo en manuales de nivel ELE Inicial (A-1 A-2) : an??lisis de materiales y propuesta did??ctica para aprendientes polacos basada en el Foco en la Forma desde un enfoque cognitivo

Resumen basado en el de la publicaci??n

An??lisis intercasos de pr??cticas docentes con TIC en las aulas del modelo 1:1 en el Pa??s Vasco

Resumen basado en el de la publicaci??n

TIC e inclusi??n en aulas de Educaci??n Secundaria de la Comunidad de Madrid : an??lisis de las pr??cticas docentes en el modelo 1 a 1

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