Photosynthetic light-harvesting complexes: fluorescent and absorption spectroscopy under two-photon (1200-1500 nm) and one-photon (600-750 nm) excitation by laser femtosecond pulses

Stepanenko, I. A.; Kompanets, V. O.; Чекалин, С. В.; Makhneva, Z. K.; Moskalenko, A. A.; Razjivin, A.P.

doi:10.1117/12.882498

Cited by 4 publications

(2 citation statements)

References 20 publications

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“…Chlorophyll fluorescence delay should be taken into account for depth profile measurements. It is recognized in literature that chlorophyll fluorescence delay depends on different environment while delay is generally less than 4 ns [38,39]. Effective temporal resolution of compact Raman LIDAR was 8 ns, hence fluorescence delay could be assumed insignificant for the presented results.…”

Section: Field Experiments In Fjordsmentioning

confidence: 84%

Remote sensing of seawater and drifting ice in Svalbard fjords by compact Raman lidar

et al. 2012

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A compact Raman LIDAR system for remote sensing of sea and drifting ice was developed at the Wave Research Center at the Prokhorov General Physics Institute of the RAS. The developed system is based on a diode pumped solid state YVO 4 :Nd laser combined with compact spectrograph equipped with gated detector. The system exhibits high sensitivity and can be used for mapping or depth profiling of different parameters within many oceanographic problems. Light weight (~20 kg) and low power consumption OCIS codes: 280.3640, 280.4788, 300.6450 IntroductionThe interest to the research in the Arctic Ocean and polar areas has been increasing in the last decades due to the growing needs for oil and gas production and to the fact that the Arctic region is a sensitive global climate indicator. Continuous diagnostics of human activity influence on the ecology and global climate changes are the most pressing goals for research in all countries located in the Arctic region. Depending on the research goals different techniques can be used for laboratory measurements while monitoring of vast areas can be carried out only by remote sensing [1][2][3]. Human activity influence on ecology can be traced by pollution detection: oil [4][5][6], chemicals or heavy metals in the ocean water [7,8]. If chemical contamination of sea is of the primary interest i.e. for ecology applications then remote detection by laser fluorescence [9] or by laser induced breakdown spectroscopy can be carried out [10][11][12][13]. Global climate change is studied on the basis of the temperature and chlorophyll distribution in the Arctic Ocean using remote methods: spaceborne radars [1,14,15], airborne microwave and laser scatterometers [16][17][18][19]. 3The Arctic Ocean is an excellent region for revealing climate changes and at the same time the Arctic Ocean has a strong influence on the climate. In the northern regions, the ice study is of the great interest due to the fact that ice serves as an effective interface between the ocean and the atmosphere, restricting exchange of heat, mass, momentum and chemical constituents. Detailed study of the global climate system and prediction of future climate changes can be made only if reliable data on different physical parameters of water and ice are available. These parameters include water and ice temperature, salinity, ice surface roughness, optical and thermodynamic properties of the snow cover, and the presence of liquid water above ice, which frequently occurs in summer when ice and snow melt at the ice surface.Conventional techniques for temperature detection include spaceborne radiometer radars [1], airborne microwave and laser scatterometers. However, temperature detection by satellite radiometer is performed in a thin 30 µm surface layer of seawater. It was found that under low speed wind conditions the temperature of surface layer was by 0.5 -1 0 C lower than in the water column [20]. The temperature detected by radars can be strongly influenced by surface waves.Frazil or grease ice can significantl...

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Section: Field Experiments In Fjordsmentioning

confidence: 84%

Remote sensing of seawater and drifting ice in Svalbard fjords by compact Raman lidar

et al. 2012

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“…Antioxidants may partly reverse these oxidation phenomena. 61 Very recently, it was observed 62,63 that LH complexes from phototrophic bacteria such as Allochromatium minutissimum contain 3-acetyl-chlorophyll (3-acetyl-Chl) as a major oxidation product of BChl. Photo-oxidation was only effective in the presence of oxygen (as well as of carotenoid) molecules.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Fluorescence Micro-Spectroscopy Study of Individual Photosynthetic Membrane Vesicles and Light-Harvesting Complexes

2013

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Single-molecule spectroscopy, by getting rid of unwanted ensemble averaging effects, has proved to be a very valuable tool in the research of individual photosynthetic light-harvesting (LH) complexes. However, to learn about real photosynthetic processes the minimal unit to study is a single photosynthetic membrane complete with all elements of its machinery. In the present work, the fluorescence spectra of excitons in lone intracytoplasmic (IC) photosynthetic membrane vesicles of the wild type purple bacterium Rhodobacter sphaeroides that involve peripheral (LH2) and core (RC-LH1-PufX) antenna pigment-protein complexes were investigated at ambient temperature under continuous-wave laser excitation into the Q(x) absorption band of the bacteriochlorophyll-a (BChl) chromophores at 594 nm. In parallel, the spectra of mutant membrane vesicles occupied by just one type of complexes (either LH2 or RC-LH1-PufX) and the spectra of individual purified LH2 and RC-LH1-PufX complexes were measured. The fluorescence from full IC membranes shows a high sensitivity to excitation intensity, being varied over more than four orders of magnitude between 0.1 W/cm(2) and 2 kW/cm(2). At low to moderate excitation intensities, the spectra of IC membranes could be well reproduced by its component spectra, the ratio of the spectra related to peripheral and core complexes being the only adjustable parameter. The spectra of both intact chromatophores and individual membrane components recorded over 1-50 s experimental time frames are robust, strongly suggesting that large spectral fluctuations hardly play a role in the functional photosynthetic process. The significant, up to 14 times, variation of the LH2 and LH1 emission ratio observed in individual IC membranes could be related to variations in the stoichiometric ratio of the peripheral and core complexes. Evidence was found for the presence of LH2 parts that are detached from efficient energy transfer pathways. Upon strong and prolonged illumination, the membrane spectra reveal significant permanent modifications. These alterations, which mostly concern peripheral antenna complexes, were shown to be due to photo-oxidation of various numbers of BChl molecules in the B850 compartment of LH2.

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Up-converted fluorescence from photosynthetic light-harvesting complexes linearly dependent on excitation intensity

Leiger

Freiberg

2015

Photosynth Res

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Weak up-converted fluorescence related to bacteriochlorophyll a was recorded from various detergent-isolated and membrane-embedded light-harvesting pigment-protein complexes as well as from the functional membranes of photosynthetic purple bacteria under continuous-wave infrared laser excitation at 1064 nm, far outside the optically allowed singlet absorption bands of the chromophore. The fluorescence increases linearly with the excitation power, distinguishing it from the previously observed two-photon excited fluorescence upon femtosecond pulse excitation. Possible mechanisms of this excitation are discussed.

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Photosynthetic light-harvesting complexes: fluorescent and absorption spectroscopy under two-photon (1200-1500 nm) and one-photon (600-750 nm) excitation by laser femtosecond pulses

Cited by 4 publications

References 20 publications

Remote sensing of seawater and drifting ice in Svalbard fjords by compact Raman lidar

Remote sensing of seawater and drifting ice in Svalbard fjords by compact Raman lidar

Fluorescence Micro-Spectroscopy Study of Individual Photosynthetic Membrane Vesicles and Light-Harvesting Complexes

Up-converted fluorescence from photosynthetic light-harvesting complexes linearly dependent on excitation intensity

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