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The bioenergetics of salt tolerance

Description: The aim of this project was to try to understand the adaptive mechanisms that organisms develop in order to respond to a sudden transformation in their environment to a salt shock.'' To study this problem we used a fresh water oxygenic photosynthetic cyanobacterium known as Synecoccus 6311. This organism suffers injury after this sudden exposure to high concentrations of sodium chloride equivalent to or even higher than that in sea water. Yet they are able to re-establish their photosynthetic a… more
Date: January 1, 1991
Creator: Packer, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Walker Branch Watershed: site description and research scope

Description: Walker Branch Watershed is located on the Oak Ridge Reservation in the Ridge and Valley section of Tennessee. The watershed (97 ha consisting of 2 subwatersheds) is underlain by Knox Dolomite; soils formed over the dolomitic substrate are deep, well-drained Typic Paleudults. The watershed is forested. The overstory is predominantly oak-hickory with lesser amounts of pine and mesic hardwoods. The Walker Branch Watershed Project was initiated in 1967 to: relate the productivity and water quality … more
Date: January 1, 1977
Creator: Harris, W. F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Studies of air pollution effects on vegetation

Description: The report consists of three parts which summarize pollutant-vegetation effects research studies. These include: oxidant effects of primary productivity in ponderosa pine in the San Bernardino National Forest; air pollution effects on vegetation related to geothermal power development; and regional assessment of air pollution impact on vegetation by mathematical modeling. A list of publications that report results of the studies is included in an appendix.
Date: January 1, 1978
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Post transcriptional regulation of chloroplast gene expression by nuclear encoded gene products

Description: The following is a review of research accomplished in the first two years of funding for the above mentioned project. The work performed is a molecular characterization of nuclear mutants of Chlamydomonas reinhardtii which are deficient in different stages in the post-transcriptional expression of a single chloroplast encoded polypeptide, the D2 protein of Photosystem II. Our long-term goals are to understand the molecular mechanisms by which nuclear gene products affect the expression of chlor… more
Date: January 1, 1992
Creator: Kuchka, Michael R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Primary change separation and a biomimetic model of photosynthetic oxygen evolution

Description: The transformation of light into the chemical energy that drives the fixation of CO/sub 2/ and the evolution of O/sub 2/ in green plant photosynthesis is mediated by two photosystems (PS I and PS II). The initial photoreactions in both photosystems consist of the absorption of light by chlorophyll a (Chl a) and the subsequent formation of chlorophyll ..pi..-cation radicals by photoejection of electrons to nearby acceptors. The identity and chemical nature of the primary donor and acceptor of PS… more
Date: January 1, 1980
Creator: Davis, M S; Forman, A; Fujita, I; Netzel, T L & Fajer, J
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Simulations of the carbon cycle in the oceans

Description: This study includes models of oceanic CO{sub 2} uptake. This perturbation simulation of carbon dioxide uptake gives strong support to estimates of oceanic uptake of fossil CO{sub 2} of order 2 GtC/yr. over the last decade. Carbon and carbon-nitrogen models are considered.
Date: January 1, 1992
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Pigment-protein complexes

Description: The photosynthetically-active pigment protein complexes of procaryotes and eucaryotes include chlorophyll proteins, carotenochlorophyll proteins, and biliproteins. They are either integral components or attached to photosynthetic membranes. Detergents are frequently required to solubilize the pigment-protein complexes. The membrane localization and detergent solubilization strongly suggest that the pigment-protein complexes are bound to the membranes by hydrophobic interactions. Hydrophobic int… more
Date: January 1, 1980
Creator: Siegelman, H W
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Picosecond electron transfer in diporphyrin models of Photosystem II of green plants

Description: Green plants and photosynthetic bacteria efficiently transform the energy of an absorbed photon into redox products. Current in vivo and in vitro studies on Photosystem II (PS II) suggest the electron donor is a chlorophyll monomer, ligated to produce the high oxidation potential of P680, and the electron acceptor is pheophytin, a metal-free chlorophyll. This study probes the behavior of this PS II model in solvents of high dielectric constant and tests the sensitivity of its charge transfer re… more
Date: January 1, 1980
Creator: Netzel, T L; Fujita, I; Wang, C B & Fajer, J
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Report on picosecond studies of electron transfer in photosynthetic models

Description: Considerable spectroscopic work on reaction centers 8RC) from photosynthetic bacteria and on photosystem I (PSI) particles from green plants has established that the initial photochemical step in these systems is the subnanosecond tranfer of an electron resulting in the creation of an oxidized donor and a reduced acceptor. For both of these systems the electron donor is a dimer. The acceptor for bacterial RC's is bacteriopheophytin, a metal-free bacteriochlorophyll. The acceptor for PSI is… more
Date: January 1, 1980
Creator: Netzel, T L; Bucks, R R; Boxer, S G & Fujita, I
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Reduction of photosynthetically active radiation under extreme stratospheric-aerosol loads

Description: The recently published hypothesis that the Cretaceous-Tertiary extinctions might be caused by an obstruction of sunlight is tested by model calculations. First we compute the total mass of stratospheric aerosols under normal atmospheric conditions for four different (measured) aerosol size distributions and vertical profiles. For comparison, the stratospheric dust masses after four volcanic eruptions are also evaluated. Detailed solar radiative transfer calculations are then performed for artif… more
Date: January 1, 1981
Creator: Gerstl, S.A.W. & Zardecki, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Investigation of the Triplet State of Chlorophylls. Technical Progress Report, May 1, 1979-April 30, 1980

Description: The triplet state of chlorophyll has been utilized as a nondestructive probe into the structural and dynamical nature of the photosynthetic apparatus, both in vitro and in isolated in vivo subunits. During the past year, using zero-field triplet state optically detected magnetic resonance spectroscopy, the research program has examined triplet energy transfer between photosynthetic pigments in solution; has isolated and studied subchloroplast particles enriched with photo-system I and the light… more
Date: January 1, 1980
Creator: Clarke, R. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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DI-TERTIABYBUTYLNITROXIDE, A HILL REAGENT

Description: Di-tertiarybutylnitroxide (DTBN), which they have tried to use as a trapping agent to identify the species giving rise to the photo-induced EPR signals in photosynthetic materials, functions as a Hill reagent with spinach chloroplasts. Evidence is presented which indicates that the reduction of DTBN is affected by photosystem II of the electron transport system of spinach chloroplasts. The reduced form of DTBN, the hydroxylamine, undergoes a photo-oxidation with spinach chloroplasts. Possible e… more
Date: January 1, 1970
Creator: Corker, Gerald A.; Klein, Melvin P.; La Font, Didier & Calvin,Melvin.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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QUANTUM CONVERSION IN PHOTOSYNTHESIS

Description: A new suggestion is made based on model work associated with similar measurements on the biological material itself. The primary quantum conversion act is an ionization occurring in a charge transfer complex. This is what it amounts to in chemical terms. But this process cannot occur in isolated charge transfer molecules in solution because the products cannot escape from each other. The primary quantum conversion as it occurs in modern photosynthesis can only take place in a laminated structur… more
Date: January 1, 1961
Creator: Calvin, Melvin
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The active site of ribulose-bisphosphate carboxylase/oxygenase

Description: The active site of ribulose-bisphosphate carboxylase/oxygenase requires interacting domains of adjacent, identical subunits. Most active-site residues are located within the loop regions of an eight-stranded {beta}/{alpha}-barrel which constitutes the larger C-terminal domain; additional key residues are located within a segment of the smaller N-terminal domain which partially covers the mouth of the barrel. Site-directed mutagenesis of the gene encoding the enzyme from Rhodospirillum rubrum ha… more
Date: January 1, 1991
Creator: Hartman, F. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Proceedings of the Fourteenth DOE solar photochemistry research conference

Description: The central themes of this year's Solar Photochemistry Research Conference encompassed initial charge separation in photosynthesis, photoinduced charge separation in other organized assemblies, electron transfer, organic and inorganic photochemistry, and photoelectrochemistry. This volume contains a copy of the program the abstracts of 29 formal presentations and 47 posters, a record of the discussion following each presentation, and an address list for the 96 attendees. Individual projects are… more
Date: January 1, 1989
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Proceedings of the ninth DOE solar photochemistry research conference

Description: This meeting brought together contractors and grantees of the Division of Chemical Sciences in its basic research program on solar photochemical energy conversion to exchange information and discuss problems of mutual interest. This volume contains the program of the meeting, the abstracts of 28 formal presentations and 42 posters, a record of questions and answers following each presentation, and a list of attendees.
Date: January 1, 1985
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Dissolved organic matter and lake metabolism. Technical progress report, 1 July 1977--30 June 1978

Description: Interactions of dissolved organic matter with inorganic nutrient cycling and regulation of the photosynthetic and decompositional metabolism of micro- and macroflora remains the focal point of these studies. Major efforts are directed towards the sources, fates, pathways, and interactions of dissolved organic matter in inorganic chemical cycling; allochthonous sources, metabolism en route, and inputs to the lake systems of increasing stages of eutrophication; and the relationships of these comp… more
Date: January 1, 1978
Creator: Wetzel, R.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Fifteenth DOE solar photochemistry research conference

Description: This is a compilation of abstracts from the Fifteenth DOE Solar Photochemistry Research Conference hosted by the Solar Energy Research Institute which took place June 2--6, 1991. A large variety of topics pertinent to solar energy conversion are covered, including photoinduced electron transfer, photochemical energy conversion, and photosynthetic energy conversion. (GHH)
Date: January 1, 1991
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Dissolved organic matter and lake metabolism. Technical progress report, 1 July 1978--30 Jun 1979

Description: Progress is reported in continuing investigations focused on integrated studies of the qualitative and quantitative cycling and metabolism of particulate and dissolved organic carbon in lakes and their inflow sources (surface and subsurface). Emphasis is placed on the sources, fates, and interactions of dissolved and particulate organic matter in relation to: (a) inorganic chemical cycling, (b) allochthonous loading to the lake system, and (c) the coupled nutrient physiology and metabolism of p… more
Date: January 1, 1979
Creator: Wenzel, R.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A structural basis for electron transfer in bacterial photosynthesis

Description: Triplet data for the primary donor in single crystals of bacterial reaction centers of Rhodobacter sphaeroides and Rhodopseudomonas viridis are interpreted in terms of the corresponding x-ray structures. The analysis of electron paramagnetic resonance data from single crystals (triplet zero field splitting and cation and triplet linewidth of the primary special pair donor of bacterial reaction centers) is extended to systems of a non-crystalline nature. A unified interpretation based on frontie… more
Date: January 1, 1989
Creator: Norris, J. R.; DiMagno, T. J.; Angerhofer, A.; Chang, C. H.; El-Kabbani, O. & Schiffer, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Time-resolved infrared studies of the dynamics of ligand binding to cytochrome c oxidase

Description: Time-resolved infrared spectroscopy (TRIRS) has been employed to study the reactions of small molecules with the cytochrome a{sub 3}-Cu{sub B} site of cytochrome c oxidase (CcO). All phases of these reactions have been investigated, from ultrafast phenomena (hundreds of femtoseconds) to relatively slow processes (milliseconds). The ligation dynamics immediately following photodissociation have been studied using a TRIR technique with time resolution of less than 1 ps. The rate of photoinitiated… more
Date: January 1, 1991
Creator: Dyer, R.B.; Peterson, K.A.; Stoutland, P.O. & Woodruff, W.H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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