The aim of this research was to increase the rate of cell division in algae by exploring the effect of combinations of lasers of various wavelengths. Literature search has identified a gap in knowledge of the potential for increase in efficiency of the electron transition between photosystem II and photosystem I. This through the use of several wavelengths of blue and or red lasers, including 405 nm, 450, and 473 nm, 635 nm, 650 nm, 680 nm, 685 nm and 700 nm to generate photons with energies more closely matching the absorption spectra of algae receptors known as pigments. This investigation underpins the realisation that photons emanating from a specific laser are absorbed by algae pigments because there is a much closer match between the emission spectrum of the laser and the absorption spectrum of the pigments within the photosystems of algae. This research examined all of the available laser wavelengths in particular combinations; the resultant data contributed to the assembly of a matrix that illustrates the most appropriate laser combinations that promote cell division within algae. Chlamydomonas reinhardtii algae cells successfully grew and divided under exposure to both the blue laser, red laser and that of white light LED when each was applied individually or combined in a sequence. The order of the sequence of using the red and blue lasers in specific cases was important. The pH was maintained between 6.9 and 7.7, with temperatures maintained between 19.00 and 25.00 ºC. For the blue lasers, the laboratory results were as follows, (irradiation time was 12 hours every time): • 405 nm blue laser produced 1.8 x cell division of the white light LED. • For 450 nm blue laser: the white light LED produced 1.5 x cell division of the blue laser 450 nm. • 473 nm blue laser produced 2 x cell division of the white light LED. • 405 nm blue laser produced 3.6 x cell division of natural day light. • 450 nm blue laser produced 1.4 x cell division of natural day light. • 473 nm blue laser produced 4 x cell division of natural day light. For the red lasers, the laboratory results were as follows, (irradiation time was 12 hours every time): • For 635 nm red laser: the white light LED produced 4 x cell division of the red laser 635 nm. • 650 nm red laser produced 1.96 x cell division of the white light LED. • 680 nm red laser produced 2.3 x cell division of the white light LED. • For 685 nm red laser: white light LED produced 1.22 x cell division of the red laser 685 nm. • 700 nm red laser produced 1.35 x cell division of the white light LED. • For 635 nm red laser: the natural day light produced 2 x cell division of the red laser 635 nm. • 650 nm red laser produced 3.9 x cell division of natural day light. • 680 nm red laser produced 4.6 x cell division of natural day light. • 685 nm red laser produced 1.6 x cell division of natural day light. • 700 nm red laser produced 2.7 x cell division of natural day light. For the combination of blue and red lasers, the laboratory results were as follows, (irradiation time was 12 hours every time): • First combination: 405 nm blue laser followed by a combination of 680 nm and 700 nm red lasers produced 4.86 x cell division of the white light LED. • Second combination: 473 nm blue laser followed by a combination of 680 nm and 700 nm red lasers produced 4.66 x cell division of the white light LED. • Third combination: a combination of 680 nm and 700 nm red lasers produced 4.43 x cell division of the white light LED.

<p>A method describing the expression and purification of PSI-N together with fusion protein, using affinity chromatography and TEV protease. Although the method proved successful, optimization is still needed due to partial degradation of PSI-N.</p>

A method describing the expression and purification of PSI-N together with fusion protein, using affinity chromatography and TEV protease. Although the method proved successful, optimization is still needed due to partial degradation of PSI-N.

Stuttgart, Univ., Diss., 2007.

Techn. Universiẗat, Diss., 1999--Berlin.

Techn. Universiẗat, Diss., 2001-- Berlin.

Techn. Universiẗat, Diss., 2003--Berlin.

University, Diss., 2004--Jena.

abstract: A vast amount of energy emanates from the sun, and at the distance of Earth, approximately 172,500 TW reaches the atmosphere. Of that, 80,600 TW reaches the surface with 15,600 TW falling on land. Photosynthesis converts 156 TW in the form of biomass, which represents all food/fuel for the biosphere with about 20 TW of the total product used by humans. Additionally, our society uses approximately 20 more TW of energy from ancient photosynthetic products i.e. fossil fuels. In order to mitigate climate problems, the carbon dioxide must be removed from the human energy usage by replacement or recycling as an energy carrier. Proposals have been made to process biomass into biofuels; this work demonstrates that current efficiencies of natural photosynthesis are inadequate for this purpose, the effects of fossil fuel replacement with biofuels is ecologically irresponsible, and new technologies are required to operate at sufficient efficiencies to utilize artificial solar-to-fuels systems. Herein a hybrid bioderived self-assembling hydrogen-evolving nanoparticle consisting of photosystem I (PSI) and platinum nanoclusters is demonstrated to operate with an overall efficiency of 6%, which exceeds that of land plants by more than an order of magnitude. The system was limited by the rate of electron donation to photooxidized PSI. Further work investigated the interactions of natural donor acceptor pairs of cytochrome c6 and PSI for the thermophilic cyanobacteria Thermosynechococcus elogantus BP1 and the red alga Galderia sulphuraria. The cyanobacterial system is typified by collisional control while the algal system demonstrates a population of prebound PSI-cytochrome c6 complexes with faster electron transfer rates. Combining the stability of cyanobacterial PSI and kinetics of the algal PSI:cytochrome would result in more efficient solar-to-fuel conversion. A second priority is the replacement of platinum with chemically abundant catalysts. In this work, protein scaffolds are employed using host-guest strategies to increase the stability of proton reduction catalysts and enhance the turnover number without the oxygen sensitivity of hydrogenases. Finally, design of unnatural electron transfer proteins are explored and may introduce a bioorthogonal method of introducing alternative electron transfer pathways in vitro or in vivo in the case of engineered photosynthetic organisms. / Dissertation/Thesis / Doctoral Dissertation Biochemistry 2014

The photosynthetic process has the unique ability to capture energy from sunlight and accumulate that energy in sugars and starch. This thesis deals with the light driven part of photosynthesis. The aim has been to investigate how the light-absorbing protein complexes Photosystem I (PS I) and Photosystem II (PS II), react upon illumination of light with lower energy (far-red light; 700-850 nm) than the absorption peak at respective primary donor, P700 and P680.  The results were unexpected. At 295 K, we showed that both PS I and PS II were able to perform photochemistry with light up to 130 nm above its respective primary donor absorption maxima. As such, it was found that the primary donors’ action spectra extended approximately 80 nm further out into the red-region of the spectrum than previously reported.  The ability to perform photochemistry with far-red light was conserved at cryogenic temperatures (&lt; 77 K) in both photosystems. By performing EPR measurements on various photosystem preparations, under different illumination conditions the origin of the effect was localized to their respective reaction center. It is also likely that underlying mechanism is analogous for PS I and PS II, given the similarities in spatial coordination of the reaction center pigments. For PS II, the results obtained allowed us to suggest a model involving a previously unknown electron transfer pathway. This model is based upon the conclusion that the primary cation from primary charge separation induced by far-red light resides primarily on ChlD1 in P680. This is in contrast to the cation being located on PD1, as has been suggested as for visible light illumination. The property to drive photochemistry with far-red wavelengths implies a hither to unknown absorption band, probably originating from the pigments that compose P700 and P680. The results presented here might clarify how the pigments inside P680 are coupled and also how the complex charge separation processes within the first picoseconds that initiate photosynthetic reactions occur.