TY - JOUR AB - Extremophilic green algae and cyanobacteria are the most abundant species in high mountain habitats, where rough climate conditions such as temperature differences, limited water retention and high ultraviolet (UV) radiation are the cause for a restricted biological diversity in favor of a few specialized autotrophic microorganisms. In this study, we investigated four algal species from alpine habitat in a sun simulator for their defense strategies in response to UV-A radiation (315-400nm) up to 13.4W/m(2) and UV-B radiation (280-315nm) up to 2.8W/m(2). Besides changes in pigment composition we discovered that primary polar metabolites like aromatic amino acids, nucleic bases and nucleosides are increasingly produced when the organisms are exposed to elevated UV radiation. Respective compounds were isolated and identified, and in order to quantify them an HPLC-DAD method was developed and validated. Our results show that especially tyrosine and guanosine were found to be generally two to three times upregulated in the UV-B exposed samples compared to the non-treated control. AU - Hartmann, A.* AU - Albert, A. AU - Ganzera, M.* C1 - 45186 C2 - 37256 CY - Lausanne SP - 149-155 TI - Effects of elevated ultraviolet radiation on primary metabolites in selected alpine algae and cyanobacteria. JO - J. Photochem. Photobiol. B-Biol. VL - 149 PB - Elsevier Science Sa PY - 2015 SN - 1011-1344 ER - TY - JOUR AB - The objective of the present study was to identify external, intrinsic or behavioural factors that significantly influenced serum 25-hydroxyvitamin D (25(OH)D) concentrations in a German survey. Data from 3061 participants in the Cooperative Health Research in the Region of Augsburg, Germany (KORA) F4 survey were used to relate potential determinants to measured mean serum 25(OH)D concentrations using multivariable regression models. The factors significantly associated with hypovitaminosis D (defined as 25(OH)D<25nmolL(-1)) were season (winter, spring and autumn), urban environment and high body mass index. In contrast, times spent in sunny regions, hours per day spent outdoors in the summer as well as additional oral intake were associated with higher 25(OH)D concentrations. These results suggest that mainly ambient UV exposure but also individual behaviour are the most important determinants for personal 25(OH)D concentrations. The analyses further showed that in winter 43% of subjects were vitamin D deficient and 42% insufficient. Even in summer over half the population has insufficient vitamin D status with 8% deficient and 47% insufficient. Therefore measures to mitigate widespread vitamin D insufficiency such as regular short-term sun exposure and/or improved dietary intake/supplementation recommendations by public health bodies need to be considered. AU - Richter, K. AU - Breitner-Busch, S. AU - Webb, A.R.* AU - Huth, C. AU - Thorand, B. AU - Kift, R.* AU - Linseisen, J. AU - Schuh, A.* AU - Kratzsch, J.* AU - Mielck, A. AU - Weidinger, S.* AU - Peters, A. AU - Schneider, A.E. C1 - 31931 C2 - 34903 SP - 120-129 TI - Influence of external, intrinsic and individual behaviour variables on serum 25(OH)D in a German survey. JO - J. Photochem. Photobiol. B-Biol. VL - 140 PY - 2014 SN - 1011-1344 ER - TY - JOUR AB - We investigated the effects of environmentally relevant dose of ultraviolet (UV)-B and photosynthetic active radiation (PAR) on saponin accumulation in leaves on the example of Centella asiatica L. Urban. For this purpose, plants were exposed to one of four light regimes i.e., two PAR intensities with or without UV-B radiation. The experiment was conducted in technically complex sun simulators under almost natural irradiance and climatic conditions. As observed, UV-B radiation increased herb and leaf production as well as the content of epidermal flavonols, which was monitored by non-destructive fluorescence measurements. Specific fluorescence indices also indicate an increase in the content of anthocyanins under high PAR; this increase was likewise observed for the saponin concentrations. In contrast, UV-B radiation had no distinct effects on saponin and sapogenin concentrations. Our findings suggest that besides flavonoids, also saponins were accumulated under high PAR protecting the plant from oxidative damage. Furthermore, glycosylation of sapogenins seems to be important either for the protective function and/or for compartmentalization of the compounds. Moreover, our study revealed that younger leaves contain higher amounts of saponins, while in older leaves the sapogenins were the most abundant constituents. Concluding, our results proof that ambient dose of UV-B and high PAR intensity distinctly affect the accumulation of flavonoids and saponins, enabling the plant tissue to adapt to the light conditions. AU - Müller, V.* AU - Albert, A. AU - Winkler, J.B. AU - Lankes, C.* AU - Noga, G.* AU - Hunsche, M.* C1 - 27511 C2 - 32706 SP - 161-169 TI - Ecologically relevant UV-B dose combined with high PAR intensity distinctly affect plant growth and accumulation of secondary metabolites in leaves of Centella asiatica L. Urban. JO - J. Photochem. Photobiol. B-Biol. VL - 127 PB - Elsevier Science PY - 2013 SN - 1011-1344 ER - TY - JOUR AB - Photosynthetic parameters were investigated in relation to light intensity (PAR and UV-B) in two Chilean Prosopis sp., Prosopis chilensis and Prosopis tamarugo in their natural habitats. The objective of this work was to compare the photosynthetic responses and to determine the degree of adaptation of both species to visible- and UV-radiation stress. One of the study sites was Refresco in the Atacama Desert, where P. tamarugo is an endemic plant and P. chilensis was introduced, and the other was Peldehue in the valley of Central Chile where only P. chilensis is present. Due to latitude, light intensity (UV-B and PAR) is higher in Refresco than in Peldehue. The parameters investigated in both species were photosystem II fluorescence, CO(2) assimilation, stomatal conductance, photosynthetic pigment composition, flavonoid absorption patterns and composition of chlorophyll-protein complexes. Fluorescence studies, CO(2) assimilation and stomatal conductance studies demonstrated that photosynthetic activity is more efficient and stable throughout the day in P. tamarugo than in P. chilensis in Refresco. Chlorophyll-protein complexes also seemed to be more stable in P. tamarugo than in P. chilensis. Photosynthetic pigment analyses indicated possible photodamage in P. chilensis trees in Refresco, but not in Peldehue. Such photodamage was absent in P. tamarugo. There was a considerable change in the flavonoid pattern between noon and afternoon hours in both species at both study sites. The physiological implications of these changes indicate that P. tamarugo is more adapted to high solar radiation than P. chilensis. AU - Lehner, G. AU - Delatorre, J.* AU - Lütz, C.* AU - Cardemil, L.* C1 - 23413 C2 - 31094 SP - 36-44 TI - Field studies on the photosynthesis of two desert Chilean plants: Prosopis chilensis and Prosopis tamarugo. JO - J. Photochem. Photobiol. B-Biol. VL - 64 IS - 1 PB - Elsevier PY - 2001 SN - 1011-1344 ER - TY - JOUR AB - The inhibition of photosynthesis after exposure to simulated solar radiation has been investigated in the marine green alga Dunaliella salina by monitoring the chlorophyll fluorescence parameter, Delta F/F-m', and the maximum Light utilization efficiency for oxygen production. 40 different irradiation regimes have been applied by combining two different levels of UV radiation with two different levels of photosynthetically active radiation (PAR), and by using 10 coloured glass filters with decreasing cut-off wavelengths ranging from 400 to 295 nm. After a 30 min exposure both Delta F/F-m' and the efficiency of oxygen production decrease under all irradiation conditions. Inhibition increases when the cut-off is shifted towards short wavelengths. The fit of the experimental data with an analytical model describing inhibition of photosynthesis as a function of a linear combination of the photon flux densities in the UV-B, UV-A and PAR allows the average weighting factors for inhibition of photosynthesis by the three spectral ranges (about 1.6, 1.9 x 10(-2) and 1.8 x 10(-4) (mu mol m(-2) s(-1))(-1) for UV-B, UV-A and PAR, respectively) to be calculated. The experimental data and the derived weighting factors are in agreement with previous results obtained under natural solar radiation. In addition, the data allow an estimation of a biological weighting function in the UV range to be made. AU - Ghetti, F.* AU - Herrmann, H.* AU - Häder, D.-P.* AU - Seidlitz, H.K. C1 - 23430 C2 - 31148 SP - 166-173 TI - Spectral dependence of the inhibition of photosynthesis under simulated global radiation in the unicellular green alga Dunaliella salina. JO - J. Photochem. Photobiol. B-Biol. VL - 48 IS - 2-3 PB - Elsevier PY - 1999 SN - 1011-1344 ER - TY - JOUR AB - A new sunlight simulator was designed and built which meets the spectral and energetic requirements of experimental ecological plant research. Its radiation is generated by a combination of four commercially available lamp types: metal halide, quartz-halogen, blue and UVB fluorescent lamps. IR radiation is filtered by a layer (20 mm) of circulating water. The plant-damaging, short-wave UV radiation is eliminated by 13 mm of borosilicate glass. The total input power of the system is 40 kW. The net illuminated space for plants is 1.2 m×1.2 m×0.25 m (length×width×height). The geometric arrangement of 184 lamps, located in specially designed aluminium reflectors, and the high reflection coefficient of the aluminium walls result in diffuse incident light. Irradiances reach more than 1000 W m-2, but less than 10-7 W m-2 below 280 nm; the measured illuminance is 102 klx; the photosynthetically active radiation (PAR, 400-700 nm) is 2200 μmol m-2 s-1. The spatial homogeneity and the temporal variation of the irradiance are satisfactory. The spectral distribution is much more similar to natural global radiation than any other simulator known. By using highly efficient and commercially available lamp types, the running costs remain low. Hence, for the first time, a simulator in the square metre range has been developed, which provides the irradiance and the temporal, spatial and spectral distribution of global radiation at an economically reasonable scale. AU - Seckmeyer, G. AU - Payer, H.D. C1 - 40388 C2 - 40067 SP - 175-181 TI - A new sunlight simulator for ecological research on plants. JO - J. Photochem. Photobiol. B-Biol. VL - 21 IS - 2-3 PY - 1993 SN - 1011-1344 ER - TY - JOUR AB - The effects of solvent pH on spectral properties and fluorescence decay kinetics were investigated in order to characterize the microenvironment of meso-tetraphenylporphine tetrasulphonate (TPPS4) taken up by cells. Steady-state absorption and fluorescence spectra of TPPS4 in buffer solutions of different pH were used to identify a ring protonated species at pH ≤ 4. This dication could also be distinguished from the unprotonated form by its altered fluorescence decay time (3.5 vs. 11.4 ns). In addition, tune-resolved spectroscopy gave some evidence of a monocationic species existing at pH 6-9. This was concluded from the occurrence of another component with a decay time of 5 ns. Measurements of the spectral and kinetic properties of the fluorescence emission of single epithelial cells (RR1022) uncubated with TPPS4 indicated that the sensitizer was mainly localized in a microenvironment with a pH of 5, a value which occurs intracellularly only within lysosomes. Cells kept in the dark exhibited the characteristic spectra of both the dication and the neutral form. The fluorescence decay showed two components with decay times of 2.6 ns ad 10.6 ns. Irradiation of the cells changed the decay times to 4.6 ns and 13.4 ns and the dication fluorescence emission peak vanished, which is in accordance with the results obtained from buffer solutions at pH ≥ 6. Therefore, we deduce that the photodynamic action leads to a rupture of the lysosomes and that the sensitizer is released into the surrounding cytoplasm. AU - Wessels, J.M. AU - Strauß, W.S.L. AU - Seidlitz, H.K. AU - Rück, A.C. AU - Schneckenburger, H. C1 - 40564 C2 - 12034 SP - 275-284 TI - Intracellular localization of meso-tetraphenylporphine tetrasulphonate probed by time-resolved and microscopic fluorescence microscopoy. JO - J. Photochem. Photobiol. B-Biol. VL - 12 IS - 3 PY - 1992 SN - 1011-1344 ER - TY - JOUR AU - Jocham, D. AU - Baumgartner, R. AU - Stepp, H. AU - Unsöld, E. C1 - 18495 C2 - 11644 SP - 183-187 TI - Clinical Experience with the Integral Photodynamic Therapy of Bladder Carcinoma. JO - J. Photochem. Photobiol. B-Biol. VL - 6 PY - 1990 SN - 1011-1344 ER - TY - JOUR AB - Photodynamic therapy PDT was given to 20 patients who had recurring superficial tumours after unsuccessful application of other treatments. The phototherapeutic results were evaluated by check-ups at 3 month intervals (endoscopy, cytology, bladder mapping, renal ultrasonography) and computed tomography (CT) examination at 8-13 month intervals. In six patients treated with PDT no tumour recurrence was found over the whole observation period up to nearly 5 years. Four patients remained free of tumour (12 and 14 months) after repeated transurethral resection (TUR) and Nd:YAG laser therapy following PDT. Due to an initial application of insufficient irradiation, four patients required a second photodynamic treatment. In one of these cases a circumscribed dysplasia which appeared at the left ostium 26 months following PDT was treated successfully using the Nd:YAG laser following TUR. In six patients slight mucosal atypia persisted for a period of at least 2.5 years. One cystectomy had to be performed because of bladder shrinkage. The dissected bladder was free of tumour. According to these preliminary results, PDT with strict patient selection (worst case situation with recommended cystectomy) is justified in the case of recurrent superficial TIS bladder carcinoma. AU - Jocham, D.* AU - Baumgartner, R. AU - Stepp, H.G. AU - Unsöld, E. C1 - 42592 C2 - 40197 SP - 183-187 TI - Clinical experience with the integral photodynamic theraphy of bladder carcinoma. JO - J. Photochem. Photobiol. B-Biol. VL - 6 IS - 1-2 PY - 1990 SN - 1011-1344 ER - TY - JOUR AU - Seidlitz, H.K. AU - Schneckenburger, H. AU - Stettmaier, K. C1 - 18459 C2 - 11111 SP - 391-400 TI - Time-resolved polarization measurements of porphyrin fluorescence in solution and in single cells. JO - J. Photochem. Photobiol. B-Biol. VL - 5 PY - 1990 SN - 1011-1344 ER - TY - JOUR AU - Sroka, R.C. AU - Ell, C.M.D.* AU - Gottschalk, W. AU - Hengst, J. AU - Unsöld, E. C1 - 33833 C2 - 40282 SP - 456 TI - Homogeneous light application and monitoring of the applied power density during PDT. JO - J. Photochem. Photobiol. B-Biol. VL - 3 IS - 3 PY - 1989 SN - 1011-1344 ER - TY - JOUR AB - The article focuses on techniques and applications of time-resolved fluorescence spectroscopy in biology and medicine. Both novel methods and well-established ones are discussed and future trends are outlined. Applications including fluorescence detection of nucleic acids, proteins, coenzymes and plant pigments and fluorescence labelling of nuclei, membranes and antibodies are outlined. In addition the fluorescence properties of photosensitizers used in photodynamic therapy are discussed. AU - Schneckenburger, H. AU - Seidlitz, H.K. AU - Eberz, J. C1 - 41211 C2 - 40294 SP - 1-19 TI - Time-resolved fluorescence in photobiology. JO - J. Photochem. Photobiol. B-Biol. VL - 2 IS - 1 PY - 1988 SN - 1011-1344 ER - TY - JOUR AU - Sroka, E. AU - Unsöld, E. C1 - 17505 C2 - 10414 TI - Homogeneous Lightapplication and Power Density Control in PDT. JO - J. Photochem. Photobiol. B-Biol. PY - 1988 SN - 1011-1344 ER -