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Sample records for incident photosynthetically active

  1. Vegetative and reproductive plasticity of broccoli at three levels of incident photosynthetically active radiation

    International Nuclear Information System (INIS)

    Francescangeli, N.; Martí, H.R.; Sangiacomo, M.A.

    2007-01-01

    To study the effects of shading on the growth, development, dry matter partitioning, and plant architecture of broccoli, ‘Legacy’ hybrid plants were grown in pots in a greenhouse under black shading meshes to generate different levels of photosynthetically active radiation (PAR). The average incident PAR was 23 mol PPF m –2 d –1 under control conditions, 15.2 under a 35% mesh, and 6.7 under a 70% mesh. The air temperature was within the range 15-22°C. As shading increased so did the duration of the growth cycle and the leaf area (LA). Shading did not affect the number of leaves, although the upper ones were more erect. The stem length and the accumulated intercepted PAR (IPAR) were negatively related. Inflorescence diameter and commercial fresh weight decreased only with the 70% mesh. Shading did not affect stem dry weight (DW) but altered dry matter allocation in the root and spear. The DW of the leaves maintained an average 45.7% of the total DW despite the greater LA developed under shade. The net assimilation rate diminished with the reduction of IPAR, and the LA increased; the plant relative growth rate was therefore practically constant. With increased shading, the leaves and the stem became the dominant photosynthate sinks. The commercial fresh weight achieved with 15.2 mol photosynthetic photon flux (PPF) m –2 d –1 was equivalent to that obtained with 23 mol PPF m –2 d –1 , but the cycle was extended for 4.5 days. With 6.7 mol PPF m –2 d –1 , yield diminished because of the lower DW produced in a cycle extended by 15 days, and because more dry matter was allocated to the stem than to the spear. Based on these results, broccoli could be considered a shade-tolerant plant. (author) [es

  2. The effect of nitrogen on the development and photosynthetic activity ...

    African Journals Online (AJOL)

    Whole plant net photosynthetic rates appeared to vary according to the units in which the activity is expressed. The optimum levels of photosynthetic activity differed with the stage of development, depending on the basis of expression. The form and concentration of nitrogen applied influenced morphological development ...

  3. Dynamics of photosynthetic activity of cyanobacteria after gut ...

    African Journals Online (AJOL)

    African Journal of Biotechnology ... carp and goldfish, whereas there was a significant stimulation of photosynthetic activity of diatom and green algae following the depressed cyanobacteria during cultivation. The mainly stimulated eukaryotic algae species were Fragilariaceae and Scenedesmus obliquus by microscopy.

  4. A novel multipoint measuring system of photosynthetically active radiation

    International Nuclear Information System (INIS)

    Palva, L.; Garam, E.; Manoochehri, F.; Sepponen, R.; Hari, P.; Rajala, K.; Ruotoistenmaki, H.; Seppala, I.

    1998-01-01

    A novel multipoint measuring system of photosynthetically active radiation (PAR) has been designed. It is used as a component of a field measurement system of photosynthesis. The system consists of a multichannel fiberoptic sensor, Intel 486-based microcomputer (PC) with software for control and analysis and interface electronics. The fiberoptic sensor comprises 800 measuring points which are arranged in a regular grid on a plane. This grid is attached to a cuvette to observe the spatial and temporal distribution of PAR falling on the needles along with simultaneous measurements of CO 2 exchange. PAR is registered through a fiberoptic bundle using a charge coupled device (CCD) sensor. The system has been in operation between July and October 1996 within a Scots pine canopy. The results demonstrate that the obtained regression between the photosynthetic rate estimated with the multipoint PAR measuring system and the measured CO 2 exchange rate is as tight within a canopy as in unshaded conditions. (author)

  5. Photosynthetic activity, photoprotection and photoinhibition in intertidal microphytobenthos as studied in situ using variable chlorophyll fluorescence

    Science.gov (United States)

    Serôdio, João; Vieira, Sónia; Cruz, Sónia

    2008-06-01

    The photosynthetic activity of microphytobenthos biofilms was studied in situ on an intertidal mudflat of the Ria de Aveiro, Portugal. Time series of physical variables characterizing the microenvironment at the sediment photic zone (incident solar irradiance, temperature, salinity), photophysiological parameters and productive biomass of undisturbed microalgal assemblages were measured during daytime low-tide periods along one spring-neap tidal cycle, with the objective of (1) characterizing the short-term variability in photosynthetic activity in situ, (2) relating it with the changing environmental conditions and (3) with the operation of physiologically (xanthophyll cycle) and behaviorally (vertical migration) based photoprotective processes, and (4) assessing the occurrence of photoinhibition. Pulse Amplitude Modulated (PAM) fluorometry was applied to measure photosynthetic activity (the effective and maximum quantum yield of photosystem II, Δ F/ Fm' and Fv/ Fm; the photosynthesis index EFY; rapid light-response curves (RLC)), the photoprotective operation of the xanthophyll cycle and photoinhibition (non-photochemical quenching, NPQ; quantum efficiency of open RCs, Fv'/ Fm'), and vertical migration (productive biomass, Fo). The photosynthetic activity was found to be strongly affected by the cumulative light dose received during the morning low-tide periods. The fluorescence indices Δ F/ Fm', EFY, Fv'/ Fm' and RLC parameters were more depressed under high irradiances when clear sky was present during the morning low tide than when foggy conditions reduced the light dose received during a comparable period. Productive biomass exhibited maximum values in the first hours of the morning, followed by a steep decrease when irradiance reached moderate levels, due to the downward migration of the microalgae. This photophobic migratory response appeared to display a photoprotective role, allowing Δ F/ Fm' to remain near optimum values until irradiance reached

  6. Influence of stomatic aperture on photosynthetic activity of bean-seedlings leaves

    International Nuclear Information System (INIS)

    Suarez Moya, J.; Fernandez Gonzalez, J.

    1984-01-01

    The present paper contains the data of photosynthetic activity and stomatic aperture of bean-seedlings Ieaves, and the relations obtained with both results. It has been observed that the product of photosynthetic activity by the resistance; to transpiration measured by a promoter ia a constant, between some limits. (Author) 45 refs

  7. Hyperspectral estimation of corn fraction of photosynthetically active radiation

    International Nuclear Information System (INIS)

    Yang Fei; Zhang Bai; Song Kaishan

    2008-01-01

    Fraction of absorbed photosynthetically active radiation (FPAR) is one of the important variables in many productivity and biomass estimation models, this analyzed the effect of FPAR estimation with hyperspectral information, which could provide the scientific support on the improvement of FPAR estimation, remote sensing data validation, and the other ecological models. Based on the field experiment of corn, this paper analyzed the correlations between FPAR and spectral reflectance or the differential coefficient, and discussed the mechanism of FPAR estimation, studied corn FPAR estimation with reflectance, first differential coefficient, NDVI and RVI. The reflectance of visible bands showed much better correlations with FPAR than near-infrared bands. The correlation curve between FPAR and differential coefficient varied more frequently and greatly than the curve of FPAR and reflectance. Reflectance and differential coefficient both had good regressions with FPAR of the typical single band, with the maximum R2 of 0.791 and 0.882. In a word, differential coefficient and vegetation index were much effective than reflectance for corn FPAR estimating, and the stepwised regression of multibands differential coefficient showed the best regression with R2 of 0.944. 375 nm purpled band and 950 nm near-infraed band absorbed by water showed prodigious potential for FPAR estimating precision. On the whole, vegetation index and differential coefficient have good relationships with FPAR, and could be used for FAPR estimation. It would be effective of choosing right bands and excavating the hyperspectral data to improve FPAR estimating precision

  8. Mapping diffuse photosynthetically active radiation from satellite data in Thailand

    Science.gov (United States)

    Choosri, P.; Janjai, S.; Nunez, M.; Buntoung, S.; Charuchittipan, D.

    2017-12-01

    In this paper, calculation of monthly average hourly diffuse photosynthetically active radiation (PAR) using satellite data is proposed. Diffuse PAR was analyzed at four stations in Thailand. A radiative transfer model was used for calculating the diffuse PAR for cloudless sky conditions. Differences between the diffuse PAR under all sky conditions obtained from the ground-based measurements and those from the model are representative of cloud effects. Two models are developed, one describing diffuse PAR only as a function of solar zenith angle, and the second one as a multiple linear regression with solar zenith angle and satellite reflectivity acting linearly and aerosol optical depth acting in logarithmic functions. When tested with an independent data set, the multiple regression model performed best with a higher coefficient of variance R2 (0.78 vs. 0.70), lower root mean square difference (RMSD) (12.92% vs. 13.05%) and the same mean bias difference (MBD) of -2.20%. Results from the multiple regression model are used to map diffuse PAR throughout the country as monthly averages of hourly data.

  9. PARduino: A Simple Device Measuring and Logging Photosynthetically Active Radiation

    Science.gov (United States)

    Barnard, H. R.; Findley, M. C.

    2013-12-01

    Photosynthetically Active Radiation (PAR, 400 to 700 nm) is one of the primary controls of forest carbon and water relations. In complex terrain, PAR has high spatial-variability. Given the high cost of commercial datalogging equipment, spatially-distributed measurements of PAR have been typically modeled using geographic coordinates and terrain indices. Here, we present a design for a low cost, field-deployable device for measuring and logging PAR built around an Arduino microcontroller (we named it PARduino). PARduino provides for widely distributed sensor arrays and tests the feasibility of using hobbyist-grade electronics for collecting scientific data. PARduino components include a LiCor quantum sensor, EME Systems signal converter/amplifier, and Sparkfun's Arduino Pro Mini microcontroller. Additional components include a real time clock, a microSD flash memory card, and a custom printed circuit board (PCB). We selected the components with an eye towards ease of assembly. Everything can be connected to the PCB using through-hole soldering techniques. Since the device will be deployed in remote research plots that lack easy access to line power, battery life was also a consideration in the design. Extended deployment is possible because PARduino's software keeps it in a low-power sleep mode until ready to make a measurement. PARduino will be open-source hardware for use and improvement by others.

  10. A cost-effective microbial fuel cell to detect and select for photosynthetic electrogenic activity in algae and cyanobacteria

    NARCIS (Netherlands)

    Luimstra, V.M.; Kennedy, S.J.; Güttler, J.; Wood, S.A.; Williams, D.E.; Packer, M.A.

    2014-01-01

    This work describes the development of an easily constructed, cost-effective photosynthetic microbial fuel cell design with highly reproducible electrochemical characteristics that can be used to screen algae and cyanobacteria for photosynthetic electrogenic activity. It is especially suitable for

  11. Use efficiency of photosynthetically active radiation by tomato plants grown in different environments

    International Nuclear Information System (INIS)

    Radin, B.; Bergamaschi, H.; Reisser Junior, C.; Barni, N.A.; Matzenauer, R.; Didone, I.A.

    2003-01-01

    Crop biomass production is related to the amount of photosynthetically active radiation intercepted and absorbed by the leaves, as well as to their efficiency of conversion of this radiant energy into chemical energy through photosynthesis. The objective of this study was to evaluate the radiation use efficiency by tomato plants (Lycopersicon esculentum Mill.) grown in different environments. Experiments were carried out in plastic-covered greenhouses with and without anti insects screens and at open air plots, in different growth periods (spring-summer and summer-autumn) during the 1999/2000 crop season. Measurements of dry above-ground biomass and leaf area index throughout both crop cycles were performed, and the incident and transmitted radiation fluxes were registered. The greenhouse with anti insects screens had less incident radiation, but resulted in higher use efficiency: 0.44 and 0.60 g dry matter mol -1 during the first and second cycles, respectively. Outside the greenhouses, there was a higher amount of incident radiation, however a lower use efficiency (0.30 and 0.32 g mol -1 for the first and second cycles, respectively), while the greenhouse without anti insects screens had intermediate values (0.45 and 0.53 g mol -1 ). (author) [pt

  12. Photosynthetic activity in the rootstock of hybrid peach trees submitted to water restriction and flooding

    OpenAIRE

    Martinazzo, Emanuela G.; Perboni, Anelise T.; Farias, Márcio E.; Bianchi, Valmor J.; Bacarin, Marcos A.

    2011-01-01

    This study aimed to evaluate the effect of flooding and water restriction (drought) on the photosynthetic activity in plants of the hybrid rootstock 'GxN-9' (Prunus dulcis Mill. × Prunus persica L. Bastsch), grown in a greenhouse. Chlorophyll fluorescence and gas exchange were analyzed in plants of approximately 12 months. The reduction of photosynthetic activity in both the stresses were associated with decreased carboxylation efficiency, but without affecting the internal concentration of c...

  13. Effect of Temperature and light intensity on growth and Photosynthetic Activity of Chlamydomonas reinhard II

    International Nuclear Information System (INIS)

    Alfonsel Jaen, M.; Fernandez Gonzalez, J.

    1985-01-01

    The effect of five temperatures (15,20,25,30 and 35 degree centigree) and two levels of illumination on growth and photosynthetic activity of Chlamydomonas reinhard II has been studied. The growth of the cultures was evaluated by optical density. Photosynthetic activity has been carried out studying either the assimilation rate of C0 2 labelled with C-14 or the oxygen evolution by means of polarographic measurements. The maximum photosynthetic rate has been obtained at 25 degree centigree for the lower level of illumination (2400 lux) and at 35 degree centigree for the higher one (13200 lux) and at 35 degree centigree for the higher ono (13200 lux). These results suggest an interaction of temperature and illumination on photosynthetic activity. (Author) 37 refs

  14. Photosynthetic Activity in Green Hairy Roots : Ultrastructure of Plastid and Correlation of Chlorophyll and Secondary Metabolites

    OpenAIRE

    Yumio, Toda; Toshio, Aoki; Kayo, Yoshimatsu; Koichiro, Shimomura; Nano-Fabrication Group, Nanomaterial Laboratory, National Institute for Materials Science; Department of Applied Biological Sciences, Nihon University; Tsukuba Medicinal Plant Research Station, National Institute of Health Sciences; Faculty of Life Science, Toyo University

    2002-01-01

    Ultrastructure of the plastid and photosynthetic activity in green hairy roots of Amsonia elliptica, Lippia dulcis and Digitalis lanata were investigated. Plastids observed in A. elliptica were not like normal chloroplasts in leaves or leucoplasts in roots, but an amyloplast-like structure, containing large starch granules with thylakoid membranes around them. In contrast the plastids in D. lanata were chloroplast-like, and just intermediate in L. dulcis. The photosynthetic oxygen evolution a...

  15. Chemical composition and photosynthetically active radiation of forage grasses under irrigation

    Directory of Open Access Journals (Sweden)

    Edilane Aparecida da Silva

    2012-03-01

    Full Text Available The present study aimed to estimate the photosynthetically active radiation of tropical forage grasses in ten cutting dates, under irrigation. The following treatments were used: Brachiaria decumbens grass (Brachiaria decumbens cultivar Basilisk, Marandu grass (Brachiaria brizantha cultivar Marandu, Xaraes grass (Brachiaria brizantha, cultivar Xaraes, Mombaça grass (Panicum maximum cultivar Mombaça, Tanzania grass (Panicum maximum, cultivar Tanzania and Tifton 85 grass (Cynodon spp cultivar Tifton 85. The weather parameters were collected by an automatic meteorological station installed in the location and used for irrigation management. The experiment was arranged in a split-plot completely randomized block design, considering the grasses as plots and cutting seasons as subplots, with four replications in a 6 × 10 factorial arrangement, six grasses and ten cutting seasons. The results indicated increased use of photosynthetically active radiation in the wet season, in relation to the dry-wet season transition. Basilisk presented the highest values of photosynthetically active radiation (1,648.9 mE. The variables studied were affected by photosynthetically active radiation. The grass cultivars presented different light interceptions. The values of 87; 90; 90; 88; 92 and 77% were found for grass cultivars Basilisk, Marandu, Mombaça, Tanzania, Xaraes and Tifton 85, respectively. Differences were observed in forage accumulation rates for the grass plants studied. The grasses with the best productive performance were Brachiaria decumbens cultivar Basilisk and B. brizantha cultivar Xaraes. The highest values of crude protein and neutral detergent fiber were observed for Tifton 85. The use of photosynthetically active radiation was different among the grasses evaluated. There is a positive association between photosynthetically active radiation and dry matter production. Besides, photosynthetically active radiation indirectly affects crude protein

  16. Using a simple apparatus to measure direct and diffuse photosynthetically active radiation at remote locations.

    Directory of Open Access Journals (Sweden)

    Michael J Cruse

    Full Text Available Plant canopy interception of photosynthetically active radiation (PAR drives carbon dioxide (CO2, water and energy cycling in the soil-plant-atmosphere system. Quantifying intercepted PAR requires accurate measurements of total incident PAR above canopies and direct beam and diffuse PAR components. While some regional data sets include these data, e.g. from Atmospheric Radiation Measurement (ARM Program sites, they are not often applicable to local research sites because of the variable nature (spatial and temporal of environmental variables that influence incoming PAR. Currently available instrumentation that measures diffuse and direct beam radiation separately can be cost prohibitive and require frequent adjustments. Alternatively, generalized empirical relationships that relate atmospheric variables and radiation components can be used but require assumptions that increase the potential for error. Our goal here was to construct and test a cheaper, highly portable instrument alternative that could be used at remote field sites to measure total, diffuse and direct beam PAR for extended time periods without supervision. The apparatus tested here uses a fabricated, solar powered rotating shadowband and other commercially available parts to collect continuous hourly PAR data. Measurements of total incident PAR had nearly a one-to-one relationship with total incident radiation measurements taken at the same research site by an unobstructed point quantum sensor. Additionally, measurements of diffuse PAR compared favorably with modeled estimates from previously published data, but displayed significant differences that were attributed to the important influence of rapidly changing local environmental conditions. The cost of the system is about 50% less than comparable commercially available systems that require periodic, but not continual adjustments. Overall, the data produced using this apparatus indicates that this instrumentation has the

  17. Transmission and Distribution of Photosynthetically Active Radiation (PAR) for Biomass Production in Exploration Missions [7226-270], Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) proposes to develop a plant lighting system which collects, transmits and distributes photosynthetically active radiation (PAR) for...

  18. System to determine leaf photosynthetic activity by means of 14CO2

    International Nuclear Information System (INIS)

    Fernandez Gonzalez, J.

    1977-01-01

    A method to determine leaf photosynthetic activity is described. 14 CO 2 labeled air is produced from 14 CO 3 Ba and stored in a poliethylene balloon and supplied by means of an automatic dispenser to a perspex chamber inside of which is the leaf. (author) [es

  19. Nitrogen fixation and diurnal changes of photosynthetic activity in Arctic soil crusts at different development stage

    Czech Academy of Sciences Publication Activity Database

    Pushkareva, E.; Kvíderová, Jana; Šimek, Miloslav; Elster, Josef

    2017-01-01

    Roč. 79, 1 March 2017 (2017), s. 21-30 ISSN 1164-5563 Institutional support: RVO:60077344 ; RVO:67985939 Keywords : Soil crust * Arctic * Photosynthetic activity Subject RIV: EH - Ecology, Behaviour; EH - Ecology, Behaviour (BC-A) OBOR OECD: Ecology; Ecology (BC-A) Impact factor: 2.445, year: 2016

  20. Solar PAR and UVR modify the community composition and photosynthetic activity of sea ice algae.

    Science.gov (United States)

    Enberg, Sara; Piiparinen, Jonna; Majaneva, Markus; Vähätalo, Anssi V; Autio, Riitta; Rintala, Janne-Markus

    2015-10-01

    The effects of increased photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) on species diversity, biomass and photosynthetic activity were studied in fast ice algal communities. The experimental set-up consisted of nine 1.44 m(2) squares with three treatments: untreated with natural snow cover (UNT), snow-free (PAR + UVR) and snow-free ice covered with a UV screen (PAR). The total algal biomass, dominated by diatoms and dinoflagellates, increased in all treatments during the experiment. However, the smaller biomass growth in the top 10-cm layer of the PAR + UVR treatment compared with the PAR treatment indicated the negative effect of UVR. Scrippsiella complex (mainly Scrippsiella hangoei, Biecheleria baltica and Gymnodinium corollarium) showed UV sensitivity in the top 5-cm layer, whereas Heterocapsa arctica ssp. frigida and green algae showed sensitivity to both PAR and UVR. The photosynthetic activity was highest in the top 5-cm layer of the PAR treatment, where the biomass of the pennate diatom Nitzschia frigida increased, indicating the UV sensitivity of this species. This study shows that UVR is one of the controlling factors of algal communities in Baltic Sea ice, and that increased availability of PAR together with UVR exclusion can cause changes in algal biomass, photosynthetic activity and community composition. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Selecting microalgae with high lipid productivity and photosynthetic activity under nitrogen starvation

    NARCIS (Netherlands)

    Benvenuti, G.; Bosma, R.; Cuaresma Franco, M.; Janssen, M.G.J.; Barbosa, M.J.; Wijffels, R.H.

    2015-01-01

    An economically feasible microalgal lipid industry heavily relies on the selection of suitable strains. Because microalgae lipid content increases under a range of adverse conditions (e.g. nutrient deprivation, high light intensity), photosynthetic activity is usually strongly reduced. As a

  2. Microbial solar cells: applying photosynthetic and electrochemically active organisms

    NARCIS (Netherlands)

    Strik, D.P.B.T.B.; Timmers, R.A.; Helder, M.; Steinbusch, K.J.J.; Hamelers, H.V.M.; Buisman, C.J.N.

    2011-01-01

    Microbial solar cells (MSCs) are recently developed technologies that utilize solar energy to produce electricity or chemicals. MSCs use photoautotrophic microorganisms or higher plants to harvest solar energy, and use electrochemically active microorganisms in the bioelectrochemical system to

  3. Characteristics of diurnal pattern of global photosynthetically-active ...

    African Journals Online (AJOL)

    A two year data (September 1992 August 1994) on photosynhetically-active radiation (PAR) measured at Ilorin (Lat.: 832´N. Long.:434´E) using LI-190SA quantum sensor are analysed both on daily and monthly mean diurnal bases. This was done with the aim of characterizing the diurnal pattern of this radiation at this ...

  4. Effect of low-dose 60Co gamma irradiation on the photosynthetic activity of maize seedlings

    International Nuclear Information System (INIS)

    Turcsanyi, G.

    1979-01-01

    Photosynthesis investigations were carried out on maize seedlings treated with 1000 rad of 60 Co gamma irradiation prior to sowing. The aim of the work was to find out, to what degree the individual processes of photosynthesis are affected by small doses of irradiation. The increase in weight, the chlorophyll a, chlorophyll b and carotinoid content as well as the photosynthetic O 2 -evolution and 14 CO 2 -fixation of the seedlings were measured. The results indicate that, in contradiction to the data given in the literature, the occasional increase in weight caused by small-dose irradiation is not in connection with the membrane-bound part of the photosynthetic apparatus, but it is the consequence of the increased activity of the Calvin-cycle enzymes in the stroma of the chloroplasts. (author)

  5. Progress in Remote Sensing of Photosynthetic Activity over the Amazon Basin

    Science.gov (United States)

    Resende de Sousa, Celio Helder; Hilker, Thomas; Waring, Richard; Mendes De Moura, Yhasmin; Lyapustin, Alexei

    2017-01-01

    Although quantifying the massive exchange of carbon that takes place over the Amazon Basin remains a challenge, progress is being made as the remote sensing community moves from using traditional, reflectance-based vegetation indices, such as the Normalized Difference Vegetation Index (NDVI), to the more functional Photochemical Reflectance Index (PRI). This new index, together with satellite-derived estimates of canopy light interception and Sun-Induced Fluorescence (SIF), provide improved estimates of Gross Primary Production (GPP). This paper traces the development of these new approaches, compares the results of their analyses from multiple years of data acquired across the Amazon Basin and suggests further improvements in instrument design, data acquisition and processing. We demonstrated that our estimates of PRI are in generally good agreement with eddy-flux tower measurements of photosynthetic light use efficiency (epsilon) at four sites in the Amazon Basin: r(exp 2) values ranged from 0.37 to 0.51 for northern flux sites and to 0.78for southern flux sites. This is a significant advance over previous approaches seeking to establish a link between global-scale photosynthetic activity and remotely-sensed data. When combined with measurements of Sun-Induced Fluorescence (SIF), PRI provides realistic estimates of seasonal variation in photosynthesis over the Amazon that relate well to the wet and dry seasons. We anticipate that our findings will steer the development of improved approaches to estimate photosynthetic activity over the tropics.

  6. Progress in Remote Sensing of Photosynthetic Activity over the Amazon Basin

    Directory of Open Access Journals (Sweden)

    Celio Helder Resende de Sousa

    2017-01-01

    Full Text Available Although quantifying the massive exchange of carbon that takes place over the Amazon Basin remains a challenge, progress is being made as the remote sensing community moves from using traditional, reflectance-based vegetation indices, such as the Normalized Difference Vegetation Index (NDVI, to the more functional Photochemical Reflectance Index (PRI. This new index, together with satellite-derived estimates of canopy light interception and Sun-Induced Fluorescence (SIF, provide improved estimates of Gross Primary Production (GPP. This paper traces the development of these new approaches, compares the results of their analyses from multiple years of data acquired across the Amazon Basin and suggests further improvements in instrument design, data acquisition and processing. We demonstrated that our estimates of PRI are in generally good agreement with eddy-flux tower measurements of photosynthetic light use efficiency (ε at four sites in the Amazon Basin: r2 values ranged from 0.37 to 0.51 for northern flux sites and to 0.78 for southern flux sites. This is a significant advance over previous approaches seeking to establish a link between global-scale photosynthetic activity and remotely-sensed data. When combined with measurements of Sun-Induced Fluorescence (SIF, PRI provides realistic estimates of seasonal variation in photosynthesis over the Amazon that relate well to the wet and dry seasons. We anticipate that our findings will steer the development of improved approaches to estimate photosynthetic activity over the tropics.

  7. MODIS/Terra+Aqua Photosynthetically Active Radiation Daily/3-Hour L3 Global 5km SIN Grid V006

    Data.gov (United States)

    National Aeronautics and Space Administration — The MCD18A2 Version 6 is a MODIS Terra and Aqua combined Photosynthetically Active Radiation (PAR) gridded L3 product produced daily at 5 kilometer pixel resolution...

  8. NOAA Climate Data Record (CDR) of Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), Version 4

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains gridded daily Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) derived from the NOAA Climate Data...

  9. Study the effect of insecticide dimethoate on photosynthetic pigments and photosynthetic activity of pigeon pea: Laser-induced chlorophyll fluorescence spectroscopy.

    Science.gov (United States)

    Pandey, Jitendra Kumar; Dubey, Gunjan; Gopal, R

    2015-10-01

    Pigeon pea is one of the most important legume crops in India and dimethoate is a widely used insecticide in various crop plants. We studied the effect of dimethoate on growth and photosynthetic activity of pigeon pea plants over a short and long term exposure. Plant growth parameters, photosynthetic pigment content and chlorophyll fluorescence response of pigeon pea (Cajanus cajan L.) plants treated with various concentrations of the insecticide dimethoate (10, 20, 40 and 80 ppm) have been compared for 30 days at regular intervals of 10 days each. Laser induced chlorophyll fluorescence spectra and fluorescence-induction kinetics (FIK) curve of dimethoate treated pigeon pea plants were recorded after 10, 20 and 30 days of treatment. Fluorescence intensity ratio at the two fluorescence maxima (F685/F730) was calculated by evaluating curve-fitted parameters. The variable chlorophyll fluorescence decrease ratio (Rfd) was determined from the FIK curves. Our study revealed that after 10 days of treatment, 10 ppm of dimethoate showed stimulatory response whereas 20, 40 and 80 ppm of dimethoate showed inhibitory response for growth and photosynthetic activity of pigeon pea plants, but after 20 and 30 days of treatment all the tested concentrations of dimethoate became inhibitory. This study clearly shows that dimethoate is highly toxic to the pigeon pea plant, even at very low concentration (10 ppm), if used for a prolonged duration. Our study may thus be helpful in determining the optimal dose of dimethoate in agricultural practices. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Comparative study on photosynthetic activity of chloroplasts in acid and alkaline zones of Chara corallina.

    Science.gov (United States)

    Bulychev, A A; Cherkashin, A A; Rubin, A B; Vredenberg, W J; Zykov, V S; Müller, S C

    2001-03-01

    A novel experimental approach has been applied to investigate the relationship between pH banding in Chara cells and photosynthetic activity of chloroplasts located in cell regions adjacent to acid and alkaline bands. The combination of pH microelectrode technique with pulse amplitude modulation (PAM) microfluorimetry enabled parallel measurements of longitudinal pH profiles and chlorophyll fluorescence yield in acid and alkaline zones of individual Chara cells. The scanning with a pH-microelectrode along the cell length revealed the light-dependent pH pattern, i.e., alternating acid and alkaline bands with pH differences as large as 2 - 3 pH units. In parallel, measurements of chlorophyll fluorescence yield under actinic light were performed using PAM microfluorometry. It was found that the effective photochemical yield of photosystem II is substantially higher in acid than in alkaline zones. The results clearly show that the banding pattern is not confined solely to the plasmalemma but is also exhibited in alternating photosynthetic performance of the underlying chloroplast layer. Apparently, the acid regions enriched with CO2 ensure sufficient flow of this substrate to the Calvin cycle reactions, thus promoting the photosynthetic rate, whereas the alkaline zones devoid of CO2 favor radiative losses of absorbed solar energy in chloroplasts.

  11. Deficiency in phytochrome A alters photosynthetic activity, leaf starch metabolism and shoot biomass production in tomato.

    Science.gov (United States)

    Kharshiing, Eros; Sinha, Shriravi Prasad

    2016-12-01

    Photosynthesis is a key process that promotes plant growth and development. Light provides photosynthetic organisms with a major source of energy to fix carbon dioxide into organic matter. Of the entire visible light spectrum, red/blue light are known to maximise photosynthetic performance and are thus essential for proper growth and development of plants. Red and blue light stimulate synthesis of chlorophyll and orchestrate the positioning of leaves and chloroplasts for optimal utilisation of light, both of which are critical for photosynthesis. The response of plants to external light cues is accomplished via finely tuned complex photoreceptors and signaling mechanisms which enable them to continually monitor light availability and quality for optimal utilisation of light energy towards enhancing their growth. Higher plants contain a suite of photoreceptor proteins that allow them to perceive red, blue/UV-A and UV-B light. Analyses of the phyA mutant of tomato deficient in the red-light photoreceptor phytochrome A (phyA), showed reduced photosynthetic activity of isolated chloroplasts along with decreased shoot biomass in adult plants. The regulation of leaf transitory starch in the mutant was also altered as compared to the wild type (cv Moneymaker). Our results suggest a possible role for phyA in these processes in tomato. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Use of in vivo chlorophyll fluorescence to estimate photosynthetic activity and biomass productivity in microalgae grown in different culture systems

    Directory of Open Access Journals (Sweden)

    Félix L Figueroa

    2013-11-01

    Full Text Available In vivo chlorophyll fluorescence associated to Photosystem II is being used to evaluate photosynthetic activity of microalgae grown in different types of photobioreactors; however, controversy on methodology is usual. Several recommendations on the use of chlorophyll fluorescence to estimate electron transport rate and productivity of microalgae grown in thin-layer cascade cultivators and methacrylate cylindrical vessels are included. Different methodologies related to the measure of photosynthetic activity in microalgae are discussed: (1 measurement of light absorption, (2 determination of electron transport rates versus irradiance and (3 use of simplified devices based on pulse amplitude modulated (PAM fluorescence as Junior PAM or Pocket PAM with optical fiber and optical head as measuring units, respectively. Data comparisons of in vivo chlorophyll fluorescence by using these devices and other PAM fluorometers as Water-PAM in the microalga Chlorella sp. (Chlorophyta are presented. Estimations of carbon production and productivity by transforming electron transport rate to gross photosynthetic rate (as oxygen evolution using reported oxygen produced per photons absorbed values and carbon photosynthetic yield based on reported oxygen/carbon ratio are also shown. The limitation of ETR as estimator of photosynthetic and biomass productivity is discussed. Low cost:quality PAMs can promote monitoring of chlorophyll fluorescence in algal biotechnology to estimate the photosynthetic activity and biomass productivity.

  13. The Effect of Kanamycin and Tetracycline on Growth and Photosynthetic Activity of Two Chlorophyte Algae

    Directory of Open Access Journals (Sweden)

    Khawaja Muhammad Imran Bashir

    2016-01-01

    Full Text Available Antibiotics are routinely used in microalgae culture screening, stock culture maintenance, and genetic transformation. By studying the effect of antibiotics on microalgae growth, we can estimate the least value to inhibit growth of undesired pathogens in algal culture. We studied the effect of kanamycin and tetracycline on the growth and photosynthetic activity of two chlorophyte microalgae, Dictyosphaerium pulchellum and Micractinium pusillum. We measured CFU mL−1 on agar plates, optical density, fluorescence yields, and photosynthetic inhibition. Our results showed a significant effect of kan and tet on the tested microalgae species except tet, which showed a minor effect on M. pusillum. Both antibiotics are believed to interact with the protein synthesis machinery; hence, the inhibitory effect of the tested antibiotics was further confirmed by isolation and quantification of the whole cell protein. A significant reduction in protein quantity was observed at concentrations more than 5 mg L−1, except M. pusillum, which showed only a slight reduction in protein quantity even at the maximum tested concentration of tet (30 mg L−1. This study can further aid in aquaculture industry, for the maintenance of the microalgae stock cultures and it can also help the microalgae genetic engineers in the construction of molecular markers.

  14. Temperature Effects on the Growth Rates and Photosynthetic Activities of Symbiodinium Cells

    Directory of Open Access Journals (Sweden)

    Widiastuti Karim

    2015-06-01

    Full Text Available Coral bleaching is caused by environmental stress and susceptibility to bleaching stress varies among types of coral. The physiological properties of the algal symbionts (Symbiodinium spp., especially extent of damage to PSII and its repair capacity, contribute importantly to this variability in stress susceptibility. The objective of the present study was to investigate the relationship between the growth rates and photosynthetic activities of six cultured strains of Symbiodinium spp. (clades A, B, C, D, and F at elevated temperature (33 °C. We also observed the recovery of photodamaged-PSII in the presence or absence of a chloroplast protein synthesis inhibitor (lincomycin. The growth rates and photochemical efficiencies of PSII (Fv/Fm decreased in parallel at high temperature in thermally sensitive strains, B-K100 (clade B followed by culture name and A-Y106, but not in thermally tolerant strains, F-K102 and D-K111. In strains A-KB8 and C-Y103, growth declined markedly at high temperature, but Fv/Fm decreased only slightly. These strains may reallocate energy from growth to the repair of damaged photosynthetic machineries or protection pathways. Alternatively, since recoveries of photo-damaged PSII at 33 °C were modest in strains A-KB8 and C-Y103, thermal stressing of other metabolic pathways may have reduced growth rates in these two strains. This possibility should be explored in future research efforts.

  15. The distribution of leaf photosynthetic activity in a mixed grass-legume pasture canopy.

    Science.gov (United States)

    Wilson, G L; Ludlow, M M

    1983-06-01

    The distribution of net photosynthetic activity of leaves was measured in a mixed grass (Setaria sphacelata var. sericea)-legume (Desmodium intortum) pasture stand using a method based on concurrent measurement of the rate of CO2 exchange, and (14)CO2 dosing followed by rapid harvesting according to height strata. Comparisons were also made between plots which differed in the period of regrowth following defoliation.The usual superiority of leaf net photosynthetic rates of a C4 grass, compared with C3 legume leaves, was found in the upper, well illuminated strata. These rates were, however, much lower than those usually described for horizontally exposed leaves, primarily because leaves in the pasture stand were inclined to the horizontal. At greater depth in the canopies, the superiority of rates in the grass was less evident, and consequently the relative contributions of grass and legume to canopy photosynthesis became more dependent on their leaf area indices.Attention is drawn to the relative simplicity of the method for examining the contribution of leaves, which may differ according to species or position in the canopy, to productivity of the whole stand.

  16. Effect of smoke on the transmissivity of photosynthetically active radiation inside the canopy

    Science.gov (United States)

    Yamasoe, M.; von Randow, C.; Manzi, A.; Schafer, J.; Eck, T.; Holben, B.

    2005-08-01

    Biomass burning activities emit high concentrations of aerosol particles to the atmosphere. Such particles can interact with solar radiation, decreasing the amount of light reaching the surface and increasing the fraction of diffuse radiation through scattering processes. This work reports results from photosynthetic active radiation (PAR) and aerosol optical depth (AOD) measurements conducted simultaneously at Reserva Biológica do Jaru (Rondonia State, Brazil) during LBA/SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia/ Smoke, Aerosols, Clouds, Rainfall, and Climate) and RaCCI (Radiation, Cloud, and Climate Interactions in the Amazon during the Dry-to-Wet Transition Season) field experiments from 15 September to 15 November 2002. AOD values were retrieved from an AERONET (Aerosol Robotic Network) radiometer, MODIS (Moderate Resolution Spectroradiometer) and a portable sunphotometer from the United States Department of Agriculture-Forest Service. Daily mean downward PAR irradiance at the top of canopy was reduced by up to 50% due to the smoke aerosol particles. This radiation reduction affected turbulent fluxes of sensible and latent heats at the surface, observed particularly for high values of aerosol optical depth. The increase of aerosol optical depth also enhanced the transmission of photosynthetic active radiation inside the canopy. This result was a consequence of enhanced availability of diffuse radiation due to light scattering by the aerosol particles. A complex relationship was identified between light availability inside the canopy and net ecosystem exchange (NEE). The results showed that the increase of aerosol optical depth corresponded to an increase on CO2 exchange, indicating more CO2 uptake by the vegetation. However, for a higher AOD value, the corresponding NEE was lower than for intermediate values. Further studies are needed to better understand these findings, which were reported for the first time for the Amazon region under

  17. Seasonal variations in the rate of photosynthetic activity and chemical composition of the seagrass Cymodocea nodosa (Ucr. Asch.

    Directory of Open Access Journals (Sweden)

    N. Zavodnik

    1998-12-01

    Full Text Available Temporal changes in biomass, rate of photosynthetic activity and chemical composition of the seagrass Cymodocea nodosa (Ucr. Asch., under the influence of various environmental factors, were followed in the Faborsa Bay, Northern Adriatic. Throughout the year the estimated average biomass was about 130 g dry wt m-2 with annual production of 80 g C m-2. In general, leaf length, biomass and production showed clear seasonality, with maximum values during the summer period (July-September and clear minima in winter. Net oxygen production was closely related to biomass, leaf length, chlorophyll concentration, water temperature and incident light intensity. No clear seasonality was observed in the chemical composition (protein, fats, total phosphorus of C. nodosa. Over the annual cycle, the range of measured variables was 10-16% for protein, 1.7-3.1% for fat, 0.3-0.8% for phosphorus, 1.6-2.6 for nitrogen in leaves, and 5-17% for protein, 0.9-3.2% for fat, 0.1-0.6% for phosphorus and 0.9-2.8 for nitrogen in roots.

  18. Photosynthetic water oxidation: binding and activation of substrate waters for O-O bond formation.

    Science.gov (United States)

    Vinyard, David J; Khan, Sahr; Brudvig, Gary W

    2015-01-01

    Photosynthetic water oxidation occurs at the oxygen-evolving complex (OEC) of Photosystem II (PSII). The OEC, which contains a Mn4CaO5 inorganic cluster ligated by oxides, waters and amino-acid residues, cycles through five redox intermediates known as S(i) states (i = 0-4). The electronic and structural properties of the transient S4 intermediate that forms the O-O bond are not well understood. In order to gain insight into how water is activated for O-O bond formation in the S4 intermediate, we have performed a detailed analysis of S-state dependent substrate water binding kinetics taking into consideration data from Mn coordination complexes. This analysis supports a model in which the substrate waters are both bound as terminal ligands and react via a water-nucleophile attack mechanism.

  19. Induced modifications on algae photosynthetic activity monitored by pump-and-probe technique

    Energy Technology Data Exchange (ETDEWEB)

    Barbini, R.; Colao, F.; Fantoni, R.; Palucci, A.; Ribezzo, S. [ENEA, Centro Ricerche Frascati, Rome (Italy). Dip. Innovazione; Tarzillo, G.; Carlozzi, P.; Pelosi, E. [CNR, Florence (Italy). Centro Studi Microorganismi Autotrofi

    1995-12-01

    The lidar fluorosensor system available at ENEA Frascati has been used for a series of laboratory measurements on brackish-water and marine phytoplankton grown in laboratory with the proper saline solution. The system, already used to measure the laser induced fluorescence spectra of different algae species and their detection limits, has been upgraded with a short pulse Nd:YAG laser and rearranged to test a new technique based on laser pump and probe excitation. Results of this new technique for remote monitoring of the in-vivo photosynthetic activity will be presented, as measured during a field campaign carried out in Florence during the Autumn 1993, where the effects of an actinic saturating light and different chemicals have also been checked.

  20. Antimycobacterial and Photosynthetic Electron Transport Inhibiting Activity of Ring-Substituted 4-Arylamino-7-Chloroquinolinium Chlorides

    Directory of Open Access Journals (Sweden)

    Alois Cizek

    2013-09-01

    Full Text Available In this study, a series of twenty-five ring-substituted 4-arylamino-7-chloroquinolinium chlorides were prepared and characterized. The compounds were tested for their activity related to inhibition of photosynthetic electron transport (PET in spinach (Spinacia oleracea L. chloroplasts and also primary in vitro screening of the synthesized compounds was performed against mycobacterial species. 4-[(2-Bromophenylamino]-7-chloroquinolinium chloride showed high biological activity against M. marinum, M. kansasii, M. smegmatis and 7-chloro-4-[(2-methylphenylamino]quinolinium chloride demonstrated noteworthy biological activity against M. smegmatis and M. avium subsp. paratuberculosis. The most effective compounds demonstrated quite low toxicity (LD50 > 20 μmol/L against the human monocytic leukemia THP-1 cell line within preliminary in vitro cytotoxicity screening. The tested compounds were found to inhibit PET in photosystem II. The PET-inhibiting activity expressed by IC50 value of the most active compound 7-chloro-4-[(3-trifluoromethylphenylamino]quinolinium chloride was 27 μmol/L and PET-inhibiting activity of ortho-substituted compounds was significantly lower than this of meta- and para-substituted ones. The structure-activity relationships are discussed for all compounds.

  1. Characterization of Co-Cultivation of Cyanobacteria on Growth, Productions of Polysaccharides and Extracellular Proteins, Nitrogenase Activity, and Photosynthetic Activity.

    Science.gov (United States)

    Xue, Chuizhao; Wang, Libo; Wu, Tong; Zhang, Shiping; Tang, Tao; Wang, Liang; Zhao, Quanyu; Sun, Yuhan

    2017-01-01

    Cyanobacteria as biofertilizers are benefit to reduce the use of chemical fertilizers and reestablish the ecological system in soil. In general, several strains of cyanobacteria were involved in the biofertilizers. The co-cultivation of cyanobacteria were characterized on growth profile, production of polysaccharides and extracellular proteins, nitrogenase activity, and photosynthetic activity for three selected N 2 -fixing cyanobacteria, Anabaena cylindrica (B1611 and F243) and Nostoc sp. (F280). After eight-day culture, the highest dry weights were obtained in F280 pure culture and co-cultivation of B1611 and F280. Higher production of extracellular proteins and cell-bonding polysaccharides (CPS) were observed in co-cultivations compared with pure culture. The highest released polysaccharides (RPS) contents were obtained in pure culture of F280 and co-cultivation of F280 and F243. Galactose and glucose were major components of CPS and RPS in all samples. Trehalose was a specific component of RPS in F280 pure culture. Based on the monosaccharide contents of CPS and RPS, F280 was the dominant species in the related treatments of co-cultivation. The nitrogenase activities in all treatments exhibited a sharp rise at the late stage while a significant decrease existed when three cyanobacteria strains were mixed. Photosynthetic activities for all treatments were determined with rapid light curve, and the related parameters were estimated.

  2. Influence of stomatic aperture on photosynthetic activity of bean-seedlings leaves; Influencia de la apertura estomatica sobre la actividad fotosintetica de las hojas de plantas de judias

    Energy Technology Data Exchange (ETDEWEB)

    Suarez Moya, J.; Fernandez Gonzalez, J.

    1984-07-01

    The present paper contains the data of photosynthetic activity and stomatic aperture of bean-seedlings Ieaves, and the relations obtained with both results. It has been observed that the product of photosynthetic activity by the resistance; to transpiration measured by a promoter ia a constant, between some limits. (Author) 45 refs.

  3. A model for net photosynthesis of rose leaves as a function of photosynthetically active radiation, leaf temperature, and leaf age

    International Nuclear Information System (INIS)

    Lieth, J.H.; Pasian, C.C.

    1990-01-01

    A mathematical description for the relationship between the rate of rose (Rosa hybrida L.) leaf net photosynthesis and photosynthetically active radiation, leaf temperature, and leaf age is developed. The model provides a tool for the prediction of these rates for leaves growing in a rose crop canopy. (author)

  4. Seasonal and diel changes in photosynthetic activity of the snow algae Chlamydomonas nivalis (Chlorophyceae) from Svalbard determined by PAM fluorometry

    Czech Academy of Sciences Publication Activity Database

    Stibal, Marek; Elster, Josef; Šabacká, Marie; Kaštovská, Klára

    2007-01-01

    Roč. 59, - (2007), s. 265-273 ISSN 0168-6496 R&D Projects: GA AV ČR KJB6005409 Institutional research plan: CEZ:AV0Z60050516 Keywords : Chlamydomonas nivalis * photosynthetic activity * PAM fluorometry Subject RIV: EF - Botanics Impact factor: 3.039, year: 2007

  5. Influence of diurnal photosynthetic activity on the morphology, structure, and thermal properties of normal and waxy barley starch

    DEFF Research Database (Denmark)

    Goldstein, Avi; Annor, George; Vamadevan, Varatharajan

    2017-01-01

    This study investigated the influence of diurnal photosynthetic activity on the morphology, molecular composition, crystallinity, and gelatinization properties of normal barley starch (NBS) and waxy barley starch (WBS) granules from plants cultivated in a greenhouse under normal diurnal (16h light...

  6. Photosynthetic pigments and peroxidase activity of Lepidium sativum L. during assisted Hg phytoextraction.

    Science.gov (United States)

    Smolinska, Beata; Leszczynska, Joanna

    2017-05-01

    The study was conducted to evaluate metabolic answer of Lepidium sativum L. on Hg, compost, and citric acid during assisted phytoextraction. The chlorophyll a and b contents, total carotenoids, and activity of peroxidase were determined in plants exposed to Hg and soil amendments. Hg accumulation in plant shoots was also investigated. The pot experiments were provided in soil artificially contaminated by Hg and/or supplemented with compost and citric acid. Hg concentration in plant shoots and soil substrates was determined by cold vapor atomic absorption spectroscopy (CV-AAS) method after acid mineralization. The plant photosynthetic pigments and peroxidase activity were measured by standard spectrophotometric methods. The study shows that L. sativum L. accumulated Hg in its aerial tissues. An increase in Hg accumulation was noticed when soil was supplemented with compost and citric acid. Increasing Hg concentration in plant shoots was correlated with enhanced activation of peroxidase activity and changes in total carotenoid concentration. Combined use of compost and citric acid also decreased the chlorophyll a and b contents in plant leaves. Presented study reveals that L. sativum L. is capable of tolerating Hg and its use during phytoextraction assisted by combined use of compost and citric acid lead to decreasing soil contamination by Hg.

  7. Foliar nitrogen and potassium applications improve photosynthetic activities and water relations in sunflower under moisture deficit condition

    International Nuclear Information System (INIS)

    Hussain, R.A.; Ahmad, R.

    2016-01-01

    This study investigated the influence of foliar supplementation of nitrogen (N) potassium (K) and their combination on photosynthetic activities, physiological indices and water relations of two sunflower (Helianthus annuus L.) hybrids Hysen-33 and LG-5551 under water deficit condition. Studies were conducted in a wire-house at Nuclear Institute for Agriculture and Biology, Faisalabad, Pakistan. Treatments were two water stress levels [100 (control) and 60% field capacity (water deficit)], six levels of foliar spray (no spray, water spray, 1% N, 1% K, 0.5% N + 0.5% K and 1% N + 1% K) and each treatment was replicated three times. Results showed that water stress reduced the photosynthetic activities: Pn (photosynthetic rate), E (rate of tanspiration) and gs (stomatal conductance) and water relations i.e., pie w (water potential), pie s (osmotic potential) and pie p (turgor potential) . Soil moisture deficit also significantly reduced the plant height, root length, fresh and dry matter which consequently affected the plant height stress tolerance index (PHSI), root length stress tolerance index (RLSI) and dry matter stress tolerance index (DMSI) in both sunflower hybrids. However, foliar supplementation with N and K or N+K improved the photosynthetic activities, water relations and physiological indices of both the sunflower hybrids. The findings of present study suggest that application of N+K is necessary to have high plant productivity. (author)

  8. Spatial Distribution of Diffuse Attenuation of Photosynthetic Active Radiation and Its Main Regulating Factors in Inland Waters of Northeast China

    Directory of Open Access Journals (Sweden)

    Jianhang Ma

    2016-11-01

    Full Text Available Light availability in lakes or reservoirs is affected by optically active components (OACs in the water. Light plays a key role in the distribution of phytoplankton and hydrophytes, thus, is a good indicator of the trophic state of an aquatic system. Diffuse attenuation of photosynthetic active radiation (PAR (Kd(PAR is commonly used to quantitatively assess the light availability. The PAR and the concentration of OACs were measured at 206 sites, which covered 26 lakes and reservoirs in Northeast China. The spatial distribution of Kd(PAR was depicted and its association with the OACs was assessed by grey incidences(GIs and linear regression analysis. Kd(PAR varied from 0.45 to 15.04 m−1. This investigation revealed that reservoirs in the east part of Northeast China were clear with small Kd(PAR values, while lakes located in plain areas, where the source of total suspended matter (TSM varied, displayed high Kd(PAR values. The GIs and linear regression analysis indicated that the TSM was the dominant factor in determining Kd(PAR values and best correlated with Kd(PAR (R2 = 0.906, RMSE = 0.709. Most importantly, we have demonstrated that the TSM concentration is a reliable measurement for the estimation of the Kd(PAR as 74% of the data produced a relative error (RE of less than 0.4 in a leave-one-out cross validation (LOO-CV analysis. Spatial transferability assessment of the model also revealed that TSM performed well as a determining factor of the Kd(PAR for the majority of the lakes. However, a few exceptions were identified where the optically regulating dominant factors were chlorophyll-a (Chl-a and/or the chromophroic dissolved organic matter (CDOM. These extreme cases represent lakes with exceptionally clear waters.

  9. Influence on photosynthesis of starlight, moonlight, planetlight, and light pollution (reflections on photosynthetically active radiation in the universe).

    Science.gov (United States)

    Raven, J A; Cockell, C S

    2006-08-01

    Photosynthesis on Earth can occur in a diversity of organisms in the photosynthetically active radiation (PAR) range of 10 nmol of photons m(-2) s(-1) to 8 mmol of photons m(-2) s(-1). Similar considerations would probably apply to photosynthetic organisms on Earth-like planets (ELPs) in the continuously habitable zone of other stars. On Earth, starlight PAR is inadequate for photosynthetically supported growth. An increase in starlight even to reach the minimum theoretical levels to allow for photosynthesis would require a universe that was approximately ten million times older, or with a ten million times greater density of stars, than is the case for the present universe. Photosynthesis on an ELP using PAR reflected from a natural satellite with the same size as our Moon, but at the Roche limit, could support a low rate of photosynthesis at full Moon. Photosynthesis on an ELP-like satellite of a Jupiter-sized planet using light reflected from the planet could be almost 1% of the rate in full sunlight on Earth when the planet was full. These potential contributions to photosynthesis require that the contribution is compared with the rate of photosynthesis driven by direct radiation from the star. Light pollution on Earth only energizes photosynthesis by organisms that are very close to the light source. However, effects of light pollution on photosynthesis can be more widespread if the photosynthetic canopy is retained for more of the year, caused by effects on photoperiodism, with implications for the influence of civilizations on photosynthesis.

  10. Photosynthetically active radiation and comparison of methods for its estimation in equatorial Singapore

    Science.gov (United States)

    Tan, Puay Yok; Ismail, Mirza Rifqi Bin

    2016-02-01

    Photosynthetically active radiation (PAR) is an important input variable for urban climate, crop modelling and ecosystem services studies. Despite its importance, only a few empirical studies have been conducted on PAR, its relationship to global solar radiation and sky conditions and its estimation in the tropics. We report in this study, the characterisation of PAR in Singapore through direct measurements and development of models for its estimation using input variables of global solar radiation ( H), photometric radiation ( L), clearness index ( k t ) and sky view factor (SVF). Daily PAR showed a good correlation with daily H and had a comparatively small seasonal variation in PAR due to Singapore's equatorial position. The ratio of PAR to H ( PAR/ H) showed a slight depression in midyear from May to August, which correlated well with seasonal patterns in rainfall over the study period. Hourly PAR/ H increased throughout the day. Three empirical models developed in this study were able to predict daily PAR satisfactorily, with the most accurate model being one which included both H and k t as independent variables. A regression model for estimation of PAR under shaded conditions using SVF produced satisfactory estimation of daily PAR but was prone to high mean percentage error at low PAR levels.

  11. Changes in SBPase activity influence photosynthetic capacity, growth, and tolerance to chilling stress in transgenic tomato plants.

    Science.gov (United States)

    Ding, Fei; Wang, Meiling; Zhang, Shuoxin; Ai, Xizhen

    2016-09-02

    Sedoheptulose-1, 7-bisphosphatase (SBPase) is an important enzyme involved in photosynthetic carbon fixation in the Calvin cycle. Here, we report the impact of changes in SBPase activity on photosynthesis, growth and development, and chilling tolerance in SBPase antisense and sense transgenic tomato (Solanum lycopersicum) plants. In transgenic plants with increased SBPase activity, photosynthetic rates were increased and in parallel an increase in sucrose and starch accumulation was evident. Total biomass and leaf area were increased in SBPase sense plants, while they were reduced in SBPase antisense plants compared with equivalent wild-type tomato plants. Under chilling stress, when compared with plants with decreased SBPase activity, tomato plants with increased SBPase activity were found to be more chilling tolerant as indicated by reduced electrolyte leakage, increased photosynthetic capacity, and elevated RuBP regeneration rate and quantum efficiency of photosystem II. Collectively, our data suggest that higher level of SBPase activity gives an advantage to photosynthesis, growth and chilling tolerance in tomato plants. This work also provides a case study that an individual enzyme in the Calvin cycle may serve as a useful target for genetic engineering to improve production and stress tolerance in crops.

  12. Effect of smoke and clouds on the transmissivity of photosynthetically active radiation inside the canopy

    Directory of Open Access Journals (Sweden)

    M. A. Yamasoe

    2006-01-01

    Full Text Available Biomass burning activities emit high concentrations of aerosol particles to the atmosphere. Such particles can interact with solar radiation, decreasing the amount of light reaching the surface and increasing the fraction of diffuse radiation through scattering processes, and thus has implications for photosynthesis within plant canopies. This work reports results from photosynthetically active radiation (PAR and aerosol optical depth (AOD measurements conducted simultaneously at Reserva Biológica do Jaru (Rondonia State, Brazil during LBA/SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia/ Smoke, Aerosols, Clouds, Rainfall, and Climate and RaCCI (Radiation, Cloud, and Climate Interactions in the Amazon during the Dry-to-Wet Transition Season field experiments from 15 September to 15 November 2002. AOD values were retrieved from an AERONET (Aerosol Robotic Network radiometer, MODIS (Moderate Resolution Spectroradiometer and a portable sunphotometer from the United States Department of Agriculture – Forest Service. Significant reduction of PAR irradiance at the top of the canopy was observed due to the smoke aerosol particles layer. This radiation reduction affected turbulent fluxes of sensible and latent heats. The increase of AOD also enhanced the transmission of PAR inside the canopy. As a consequence, the availability of diffuse radiation was enhanced due to light scattering by the aerosol particles. A complex relationship was identified between light availability inside the canopy and net ecosystem exchange (NEE. The results showed that the increase of aerosol optical depth corresponded to an increase of CO2 uptake by the vegetation. However, for even higher AOD values, the corresponding NEE was lower than for intermediate values. As expected, water vapor pressure deficit (VPD, retrieved at 28m height inside the canopy, can also affect photosynthesis. A decrease in NEE was observed as VPD increased. Further studies are needed

  13. Moderate Thermal Stress Causes Active and Immediate Expulsion of Photosynthetically Damaged Zooxanthellae (Symbiodinium from Corals.

    Directory of Open Access Journals (Sweden)

    Lisa Fujise

    Full Text Available The foundation of coral reef biology is the symbiosis between corals and zooxanthellae (dinoflagellate genus Symbiodinium. Recently, coral bleaching, which often results in mass mortality of corals and the collapse of coral reef ecosystems, has become an important issue around the world as coral reefs decrease in number year after year. To understand the mechanisms underlying coral bleaching, we maintained two species of scleractinian corals (Acroporidae in aquaria under non-thermal stress (27°C and moderate thermal stress conditions (30°C, and we compared the numbers and conditions of the expelled Symbiodinium from these corals. Under non-thermal stress conditions corals actively expel a degraded form of Symbiodinium, which are thought to be digested by their host coral. This response was also observed at 30°C. However, while the expulsion rates of Symbiodinium cells remained constant, the proportion of degraded cells significantly increased at 30°C. This result indicates that corals more actively digest and expel damaged Symbiodinium under thermal stress conditions, likely as a mechanism for coping with environmental change. However, the increase in digested Symbiodinium expulsion under thermal stress may not fully keep up with accumulation of the damaged cells. There are more photosynthetically damaged Symbiodinium upon prolonged exposure to thermal stress, and corals release them without digestion to prevent their accumulation. This response may be an adaptive strategy to moderate stress to ensure survival, but the accumulation of damaged Symbiodinium, which causes subsequent coral deterioration, may occur when the response cannot cope with the magnitude or duration of environmental stress, and this might be a possible mechanism underlying coral bleaching during prolonged moderate thermal stress.

  14. Moderate Thermal Stress Causes Active and Immediate Expulsion of Photosynthetically Damaged Zooxanthellae (Symbiodinium) from Corals.

    Science.gov (United States)

    Fujise, Lisa; Yamashita, Hiroshi; Suzuki, Go; Sasaki, Kengo; Liao, Lawrence M; Koike, Kazuhiko

    2014-01-01

    The foundation of coral reef biology is the symbiosis between corals and zooxanthellae (dinoflagellate genus Symbiodinium). Recently, coral bleaching, which often results in mass mortality of corals and the collapse of coral reef ecosystems, has become an important issue around the world as coral reefs decrease in number year after year. To understand the mechanisms underlying coral bleaching, we maintained two species of scleractinian corals (Acroporidae) in aquaria under non-thermal stress (27°C) and moderate thermal stress conditions (30°C), and we compared the numbers and conditions of the expelled Symbiodinium from these corals. Under non-thermal stress conditions corals actively expel a degraded form of Symbiodinium, which are thought to be digested by their host coral. This response was also observed at 30°C. However, while the expulsion rates of Symbiodinium cells remained constant, the proportion of degraded cells significantly increased at 30°C. This result indicates that corals more actively digest and expel damaged Symbiodinium under thermal stress conditions, likely as a mechanism for coping with environmental change. However, the increase in digested Symbiodinium expulsion under thermal stress may not fully keep up with accumulation of the damaged cells. There are more photosynthetically damaged Symbiodinium upon prolonged exposure to thermal stress, and corals release them without digestion to prevent their accumulation. This response may be an adaptive strategy to moderate stress to ensure survival, but the accumulation of damaged Symbiodinium, which causes subsequent coral deterioration, may occur when the response cannot cope with the magnitude or duration of environmental stress, and this might be a possible mechanism underlying coral bleaching during prolonged moderate thermal stress.

  15. Effect of smoke and clouds on the transmissivity of photosynthetically active radiation inside the canopy

    Science.gov (United States)

    Yamasoe, M. A.; von Randow, C.; Manzi, A. O.; Schafer, J. S.; Eck, T. F.; Holben, B. N.

    2006-05-01

    Biomass burning activities emit high concentrations of aerosol particles to the atmosphere. Such particles can interact with solar radiation, decreasing the amount of light reaching the surface and increasing the fraction of diffuse radiation through scattering processes, and thus has implications for photosynthesis within plant canopies. This work reports results from photosynthetically active radiation (PAR) and aerosol optical depth (AOD) measurements conducted simultaneously at Reserva Biológica do Jaru (Rondonia State, Brazil) during LBA/SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia/ Smoke, Aerosols, Clouds, Rainfall, and Climate) and RaCCI (Radiation, Cloud, and Climate Interactions in the Amazon during the Dry-to-Wet Transition Season) field experiments from 15 September to 15 November 2002. AOD values were retrieved from an AERONET (Aerosol Robotic Network) radiometer, MODIS (Moderate Resolution Spectroradiometer) and a portable sunphotometer from the United States Department of Agriculture - Forest Service. Significant reduction of PAR irradiance at the top of the canopy was observed due to the smoke aerosol particles layer. This radiation reduction affected turbulent fluxes of sensible and latent heats. The increase of AOD also enhanced the transmission of PAR inside the canopy. As a consequence, the availability of diffuse radiation was enhanced due to light scattering by the aerosol particles. A complex relationship was identified between light availability inside the canopy and net ecosystem exchange (NEE). The results showed that the increase of aerosol optical depth corresponded to an increase of CO2 uptake by the vegetation. However, for even higher AOD values, the corresponding NEE was lower than for intermediate values. As expected, water vapor pressure deficit (VPD), retrieved at 28m height inside the canopy, can also affect photosynthesis. A decrease in NEE was observed as VPD increased. Further studies are needed to better

  16. Seasonally different response of photosynthetic activity to daytime and night-time warming in the Northern Hemisphere.

    Science.gov (United States)

    Tan, Jianguang; Piao, Shilong; Chen, Anping; Zeng, Zhenzhong; Ciais, Philippe; Janssens, Ivan A; Mao, Jiafu; Myneni, Ranga B; Peng, Shushi; Peñuelas, Josep; Shi, Xiaoying; Vicca, Sara

    2015-01-01

    Over the last century the Northern Hemisphere has experienced rapid climate warming, but this warming has not been evenly distributed seasonally, as well as diurnally. The implications of such seasonal and diurnal heterogeneous warming on regional and global vegetation photosynthetic activity, however, are still poorly understood. Here, we investigated for different seasons how photosynthetic activity of vegetation correlates with changes in seasonal daytime and night-time temperature across the Northern Hemisphere (>30°N), using Normalized Difference Vegetation Index (NDVI) data from 1982 to 2011 obtained from the Advanced Very High Resolution Radiometer (AVHRR). Our analysis revealed some striking seasonal differences in the response of NDVI to changes in day- vs. night-time temperatures. For instance, while higher daytime temperature (Tmax) is generally associated with higher NDVI values across the boreal zone, the area exhibiting a statistically significant positive correlation between Tmax and NDVI is much larger in spring (41% of area in boreal zone--total area 12.6×10(6) km2) than in summer and autumn (14% and 9%, respectively). In contrast to the predominantly positive response of boreal ecosystems to changes in Tmax, increases in Tmax tended to negatively influence vegetation growth in temperate dry regions, particularly during summer. Changes in night-time temperature (Tmin) correlated negatively with autumnal NDVI in most of the Northern Hemisphere, but had a positive effect on spring and summer NDVI in most temperate regions (e.g., Central North America and Central Asia). Such divergent covariance between the photosynthetic activity of Northern Hemispheric vegetation and day- and night-time temperature changes among different seasons and climate zones suggests a changing dominance of ecophysiological processes across time and space. Understanding the seasonally different responses of vegetation photosynthetic activity to diurnal temperature changes

  17. Effects of modified clay on the physiological and photosynthetic activities of Amphidinium carterae Hulburt.

    Science.gov (United States)

    Liu, Shuya; Yu, Zhiming; Song, Xiuxian; Cao, Xihua

    2017-12-01

    Among the strategies for treating harmful algal blooms, flocculation using modified clay (MC) has been widely applied in the field. This paper studied the mitigation of MC on Amphidinium carterae Hulburt, finding that MC could not only effectively remove A. carterae, but also affect the physiological activities of the residual algae and inhibit their normal growth. The superoxide dismutase (SOD) activity, catalase (CAT) activity and malondialdehyde (MDA) content of the residual algae significantly increased compared with the control, indicating that MC stimulated the accumulation of reactive oxygen species (ROS) in algal cells. In addition, the cell density was significantly correlated with the SOD activity, CAT activity and MDA content in the experiment groups, suggesting that intracellular ROS might be the main internal factor inhibiting cell growth. To reveal the mechanism of ROS generation, this paper further evaluated the effect of MC on photosynthesis in the residual microalgae, and found that compared with the control the absorption flux per photosystem II (PSII) reaction center (ABS/RC), the trapping flux per RC (TR 0 /RC) and the electron transport flux per RC (ET 0 /RC) increased, while the TR 0 /ABS and ET 0 /ABS decreased after adding 0.10g/L and 0.25g/L MC. These findings indicate that the MC led to an imbalance between photosynthetic light absorption and energy utilization and that the partial RCs became non-primary quinone electron acceptor (Q A )-RCs, further inducing the over-excitation of the active RCs. And MC caused the suppression of the electron transport chain (ETC): the ETC from the Q A to the secondary quinone electron acceptor (Q B ) was blocked and the size of plastoquinone pool decreased, which could induce the over-reduction of PSII. The over-excitation of PSII and the damaged ETC likely induce the generation of ROS during photosynthesis. Thus, MC likely induced the accumulation of intracellular ROS due to photosynthesis inhibition

  18. Estimation of absorbed photosynthetically active radiation and vegetation net production efficiency using satellite data

    International Nuclear Information System (INIS)

    Hanan, N.P.; Prince, S.D.; Begue, A.

    1995-01-01

    The amount of photosynthetically active radiation (PAR) absorbed by green vegetation is an important determinant of photosynthesis and growth. Methods for the estimation of fractional absorption of PAR (iff PAR ) for areas greater than 1 km 2 using satellite data are discussed, and are applied to sites in the Sahel that have a sparse herb layer and tree cover of less than 5%. Using harvest measurements of seasonal net production, net production efficiencies are calculated. Variation in estimates of seasonal PAR absorption (APAR) caused by the atmospheric correction method and relationship between surface reflectances and iff PAR is considered. The use of maximum value composites of satellite NDVI to reduce the effect of the atmosphere is shown to produce inaccurate APAR estimates. In this data set, however, atmospheric correction using average optical depths was found to give good approximations of the fully corrected data. A simulation of canopy radiative transfer using the SAIL model was used to derive a relationship between canopy NDVI and iff PAR . Seasonal APAR estimates assuming a 1:1 relationship between iff PAR and NDVI overestimated the SAIL modeled results by up to 260%. The use of a modified 1:1 relationship, where iff PAR was assumed to be linearly related to NDVI scaled between minimum (soil) and maximum (infinite canopy) values, underestimated the SAIL modeled results by up to 35%. Estimated net production efficiencies (ϵ n , dry matter per unit APAR) fell in the range 0.12–1.61 g MJ −1 for above ground production, and in the range 0.16–1.88 g MJ −1 for total production. Sites with lower rainfall had reduced efficiencies, probably caused by physiological constraints on photosynthesis during dry conditions. (author)

  19. PARduino: a simple and inexpensive device for logging photosynthetically active radiation.

    Science.gov (United States)

    Barnard, Holly R; Findley, Matthew C; Csavina, Janae

    2014-06-01

    Photosynthetically active radiation (PAR, 400-700 nm) is one of the primary controls of forest carbon and water relations. In complex terrain, PAR has high spatial variability. Given the high cost of commercial datalogging equipment, spatially distributed measurements of PAR have been typically modeled using geographic coordinates and terrain indices. Here, we present a design for a low-cost, field-deployable device for measuring and recording PAR built around an Arduino microcontroller-named PARduino. PARduino provides for widely distributed sensor arrays and tests the feasibility of using open-source, hobbyist-grade electronics for collecting scientific data. PARduino components include a quantum sensor, an EME Systems signal converter/amplifier and an Arduino Pro Mini microcontroller. Additional components include a real-time clock, a microSD Flash memory card and a custom printed circuit board. The components were selected for ease of assembly. We found strong agreement between the PARduino datalogger system and National Institute of Standards and Technology traceable sensors logged by an industry standard datalogger (slope = 0.99, SE < 0.01, P < 0.01; intercept = - 14.84, SE = 0.78, P < 0.01). The average difference between the two systems was 22.0 µmol m(-2) s(-1) with PARduino typically underestimating PAR. The average percentage difference between systems was 3.49%. On average, PARduino performed within the factory absolute calibration of the PAR sensor; however, larger errors occurred at low PAR levels. Using open-source technologies such as this can make it possible to develop a spatially distributed sensor network within the constraints of a typical research budget. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. An Evaluation of Semiempirical Models for Partitioning Photosynthetically Active Radiation Into Diffuse and Direct Beam Components

    Science.gov (United States)

    Oliphant, Andrew J.; Stoy, Paul C.

    2018-03-01

    Photosynthesis is more efficient under diffuse than direct beam photosynthetically active radiation (PAR) per unit PAR, but diffuse PAR is infrequently measured at research sites. We examine four commonly used semiempirical models (Erbs et al., 1982, https://doi.org/10.1016/0038-092X(82)90302-4; Gu et al., 1999, https://doi.org/10.1029/1999JD901068; Roderick, 1999, https://doi.org/10.1016/S0168-1923(99)00028-3; Weiss & Norman, 1985, https://doi.org/10.1016/0168-1923(85)90020-6) that partition PAR into diffuse and direct beam components based on the negative relationship between atmospheric transparency and scattering of PAR. Radiation observations at 58 sites (140 site years) from the La Thuille FLUXNET data set were used for model validation and coefficient testing. All four models did a reasonable job of predicting the diffuse fraction of PAR (ϕ) at the 30 min timescale, with site median r2 values ranging between 0.85 and 0.87, model efficiency coefficients (MECs) between 0.62 and 0.69, and regression slopes within 10% of unity. Model residuals were not strongly correlated with astronomical or standard meteorological variables. We conclude that the Roderick (1999, https://doi.org/10.1016/S0168-1923(99)00028-3) and Gu et al. (1999, https://doi.org/10.1029/1999JD901068) models performed better overall than the two older models. Using the basic form of these models, the data set was used to find both individual site and universal model coefficients that optimized predictive accuracy. A new universal form of the model is presented in section 5 that increased site median MEC to 0.73. Site-specific model coefficients increased median MEC further to 0.78, indicating usefulness of local/regional training of coefficients to capture the local distributions of aerosols and cloud types.

  1. Ecological, Typological Properties and Photosynthetic Activity (FAPAR of Common Beech (Fagus sylvatica L. Ecosystems in Croatia

    Directory of Open Access Journals (Sweden)

    Ivan Pilaš

    2016-12-01

    Full Text Available Background and purpose: The purpose of this study was to assess the structural and functional properties of common beech forest ecosystems in Croatia across a wide macro-climatic gradient (Mediterranean, Alpine and Continental and to gain insight into the ways they adapt to progressing short-term climatic extremes and anomalies. Material and Methods: Research was undertaken by integration of the expert based, country scale typological delineation of 13 beech ecosystem types, climatic and topographic grids and indices of ecosystem performances such as the JRC FAPAR (Fraction of Absorbed Photosynthetically Active Radiation. Results: This study reveals preferential environmental conditions for beech ecosystem types together with limiting conditions in three margins of the beech distribution area: highest altitudinal zone, south-eastern continental Pannonian zone and the Mediterranean. The results show that the common beech can adapt to a very wide range of environmental conditions: annual mean temperatures from 2.1oC to 13.5oC, annual precipitation from 739 mm to 3444 mm, and altitudinal range from 20.3 m up to 1576 m above sea level. FAPAR reveals some new insight into the adaptive potential and response mechanisms of the common beech to emerging climate change. Conclusion: The common beech has great potential to adapt to increasing spring warming by a preterm shift of phenology onset and retain relatively stable productivity during the phenology peak in July and August, unrelated to external climatic forcing. These findings indicate that the flexibility of phenological timing, especially during springtime, present one of the important mechanisms of adaptation and resilience of the common beech.

  2. Ecological, Typological Properties and Photosynthetic Activity (FAPAR of Common Beech (Fagus sylvatica L. Ecosystems in Croatia

    Directory of Open Access Journals (Sweden)

    Ivan Pilaš

    2017-01-01

    Full Text Available Background and purpose: The purpose of this study was to assess the structural and functional properties of common beech forest ecosystems in Croatia across a wide macro-climatic gradient (Mediterranean, Alpine and Continental and to gain insight into the ways they adapt to progressing short-term climatic extremes and anomalies. Material and Methods: Research was undertaken by integration of the expert based, country scale typological delineation of 13 beech ecosystem types, climatic and topographic grids and indices of ecosystem performances such as the JRC FAPAR (Fraction of Absorbed Photosynthetically Active Radiation. Results: This study reveals preferential environmental conditions for beech ecosystem types together with limiting conditions in three margins of the beech distribution area: highest altitudinal zone, south-eastern continental Pannonian zone and the Mediterranean. The results show that the common beech can adapt to a very wide range of environmental conditions: annual mean temperatures from 2.1oC to 13.5oC, annual precipitation from 739 mm to 3444 mm, and altitudinal range from 20.3 m up to 1576 m above sea level. FAPAR reveals some new insight into the adaptive potential and response mechanisms of the common beech to emerging climate change. Conclusion: The common beech has great potential to adapt to increasing spring warming by a preterm shift of phenology onset and retain relatively stable productivity during the phenology peak in July and August, unrelated to external climatic forcing. These findings indicate that the flexibility of phenological timing, especially during springtime, present one of the important mechanisms of adaptation and resilience of the common beech.

  3. Incorporating GOES Satellite Photosynthetically Active Radiation (PAR) Retrievals to Improve Biogenic Emission Estimates in Texas

    Science.gov (United States)

    Zhang, Rui; White, Andrew T.; Pour Biazar, Arastoo; McNider, Richard T.; Cohan, Daniel S.

    2018-01-01

    This study examines the influence of insolation and cloud retrieval products from the Geostationary Operational Environmental Satellite (GOES) system on biogenic emission estimates and ozone simulations in Texas. Compared to surface pyranometer observations, satellite-retrieved insolation and photosynthetically active radiation (PAR) values tend to systematically correct the overestimation of downwelling shortwave radiation in the Weather Research and Forecasting (WRF) model. The correlation coefficient increases from 0.93 to 0.97, and the normalized mean error decreases from 36% to 21%. The isoprene and monoterpene emissions estimated by the Model of Emissions of Gases and Aerosols from Nature are on average 20% and 5% less, respectively, when PAR from the direct satellite retrieval is used rather than the control WRF run. The reduction in biogenic emission rates using satellite PAR reduced the predicted maximum daily 8 h ozone concentration by up to 5.3 ppbV over the Dallas-Fort Worth (DFW) region on some days. However, episode average ozone response is less sensitive, with a 0.6 ppbV decrease near DFW and 0.3 ppbV increase over East Texas. The systematic overestimation of isoprene concentrations in a WRF control case is partially corrected by using satellite PAR, which observes more clouds than are simulated by WRF. Further, assimilation of GOES-derived cloud fields in WRF improved CAMx model performance for ground-level ozone over Texas. Additionally, it was found that using satellite PAR improved the model's ability to replicate the spatial pattern of satellite-derived formaldehyde columns and aircraft-observed vertical profiles of isoprene.

  4. Effect of Azospirillum brasilense and Burkholderia unamae Bacteria on Maize Photosynthetic Activity Evaluated Using the Photoacoustic Technique

    Science.gov (United States)

    Gordillo-Delgado, F.; Marín, E.; Calderón, A.

    2016-09-01

    In this work, the photosynthetic process of maize plants ( Zea mays), which were grown using seeds inoculated with plant growth promoting bacteria Azospirillum brasilense and Burkholderia unamae, was monitored. Photothermal and photobaric signals obtained by a time-resolved photoacoustic measurement configuration were used for measuring the oxygen evolution rate in situ. A frequency-resolved configuration of the method was utilized to determine the oxygen diffusion coefficient and the thermal diffusivity of the maize leaves. The latter parameters, which can be used as indicators of the photosynthetic activity of maize, are found to vary according to the plant-microbe interaction. Treatment with plant growth promoting bacteria induced a decrease in the oxygen diffusion coefficient of about 20 %.

  5. Measuring Photosynthetic Response to Drought Stress using Active and Passive Fluorescence

    Science.gov (United States)

    Helm, L.; Lerdau, M.; Wang, W.; Yang, X.

    2017-12-01

    Photosynthesis, the endothermic reactions involving the absorption of light and fixation and reduction of carbon dioxide by plants, plays important roles in carbon and water cycles, food security, and even weather and climate patterns. Solar radiation provides the energy for photosynthesis, but often plants absorb more solar energy than they can use to reduce carbon dioxide. This excess energy, which is briefly stored as high-energy electrons in the chloroplast, must be removed or damage to the leaf's photosynthetic machinery will occur. One important energy dissipation pathway is for the high energy electrons to return to their lower valance state and, in doing so, release radiation (fluorescence). This fluorescence (known as solar induced fluorescence (SIF) has been found to strongly correlate with gross photosynthesis. Recent advances in the remote sensing of SIF allow for large-scale real-time estimation of photosynthesis. In a warming climate with more frequent stress, remote sensing is necessary for measuring the spatial and temporal variability of photosynthesis. However, the mechanisms that link SIF and photosynthesis are unclear, particularly how the relationship may or may not change under stress. We present data from leaf-level measurements of gas exchange, pulse amplitude modulation (PAM) fluorescence, and SIF in two major tree species in North America. Water-stressed and well-watered plants were compared to determine how SIF and carbon dioxide exchange are modulated by drought diurnally and seasonally. Secondly, photosynthesis and fluorescence under high and low oxygen concentrations were compared to determine how photorespiration alters the relationship between SIF and gross photosynthesis. We find a strong correlation between SIF and steady-state fluorescence measured with conventional PAM fluorometry. Our results also indicate that drought-stress modulates the SIF-photosynthesis relationship, and this may be driven by drought-induced changes in

  6. Measurement and estimation of photosynthetically active radiation from 1961 to 2011 in Central China

    International Nuclear Information System (INIS)

    Wang, Lunche; Gong, Wei; Li, Chen; Lin, Aiwen; Hu, Bo; Ma, Yingying

    2013-01-01

    Highlights: • 6-Year observations were used to show the temporal variability of PAR and PAR/G. • Dependence of PAR on clearness index was studied in model development. • New developed models performed very well at different time scales. • The new all-weather model provided good estimates of PAR at two other sites. • Long-term variations of PAR from 1961 to 2011 in Central China were analyzed. - Abstract: Measurements of photosynthetically active radiation (PAR) and global solar radiation (G) at WHU, Central China during 2006–2011 were used to investigate the seasonal characteristics of PAR and PAR/G (PAR fraction). Both PAR and PAR fraction showed similar seasonal features that peaked in values during summer and reached their lowest in winter with annual mean values being 22.39 mol m −2 d −1 and 1.9 mol M J −1 respectively. By analyzing the dependence of PAR on cosine of solar zenith angle and clearness index at WHU, an efficient all-weather model was developed for estimating PAR values under various sky conditions, which also produced accepted estimations with high accuracy at Lhasa and Fukang. PAR dataset was then reconstructed from G for 1961–2011 through the new developed model. Annual mean daily PAR was about 23.12 mol m −2 d −1 , there was a significant decreasing trend (11.2 mol m −2 per decade) during the last 50 years in Central China, the decreases were sharpest in summer (−24.67 mol m −2 per decade) with relatively small decreases being observed in spring. Meanwhile, results also revealed that PAR began to increase at a rate of 0.1 mol m −2 per year from 1991 to 2011, which was in consistent with variation patterns of global solar radiation in the study area. The proposed all-weather PAR model would be of vital importance for ecological modeling, atmospheric environment, agricultural processes and solar energy application

  7. Scattering of ultraviolet and photosynthetically active radiation by Sorghum bicolor: influence of epicuticular wax

    International Nuclear Information System (INIS)

    Grant, R.H.; Jenks, M.A.; Rich, P.J.; Peters, P.J.; Ashworth, E.N.

    1995-01-01

    Near-isogenic mutants of Sorghum bicolor with genetic alterations affecting epicuticular wax (EW) structure but having similar canopy architecture provided a model system to examine the influence of EW on plant radiation scattering. Differences in canopies with two different sheath EW amounts showed differences in angular reflectance and transmittance. The differences varied with waveband of radiation. Canopy ultraviolet-B (UVB) and photosynthetically active radiation (PAR) backward reflectance in the principal solar plane were higher by wild-type plants (N-15) bearing reflective stalk EW filaments than mutant plants (bm-15) lacking stalk EW filaments. Between panicle emergence to anthesis the backward PAR reflectance increased more in the N-15 than bm-15 canopy. We suspect that the increase was a result of reflections from stalk facets emerging above the surface plane of the canopy foliage and exposing reflective EW. As panicles emerged above the foliage, canopy UVB and PAR forward reflectance by bm-15 increased while forward reflectance by N-15 decreased. The increased forward reflectance from bm-15 may be because of high specular reflectance from the microscopically smooth bm-15 stalk surfaces. Based on comparisons of probability distributions, significant differences in PAR and UVB canopy transmittance were detected between N-15 and bm-15. The median UVB transmittance was greater in the bm-15 canopy than the N-15 canopy, while the median PAR transmittance was the same for the two canopies. The greater transmittance in the N-15 canopy corresponded with lower EW load of the sheaths, but the difference between canopies was within the experimental error. Distinct influences of the stalk EW on canopy reflectance and transmittance were difficult to assess because of the relatively low proportion of surface area containing EW, the experimental errors associated with UVB irradiance field measurements. The optical properties of the S. bicolor canopy varied by waveband

  8. Photosynthetically-active radiation: sky radiance distributions under clear and overcast conditions

    International Nuclear Information System (INIS)

    Grant, R.H.; Heisler, G.M.; Gao, W.

    1996-01-01

    The photosynthetically active radiation (PAR), defined as the wavelength band of 0.400 μm to 0.700 μm, represents most of the visible solar radiation. Although the proportion of global irradiance that originates from diffuse sky radiation is higher for PAR than for all solar shortwave radiation, it is often assumed that the PAR diffuse sky radiation is distributed identically to that of all shortwave solar radiation. This assumption has not been tested. PAR sky radiance measurements were made in a rural area over a wide range of solar zenith angles. The distribution of PAR sky radiance was modeled using physically-based, non-linear equations.For clear skies, the normalized sky radiance distribution (N) was best modeled using the scattering angle (ψ) and the zenith position in the sky (Θ) as N (Θ, ψ) = 0.0361 [6.3 + (1 + cos 2 Θ / (1 - cos ψ)] [1-e -0.31 sec ( Θ]. The angle Ψ is defined by cos ψ = cos Θ cos Θ * + sin Θ sin Θ * cos Φ, where solar zenith angle is Θ* and the difference in azimuth between the sun and the position in the sky is Φ. Modeling of the overcast sky depended on the visibility of the solar disk. The translucent middle/high cloud overcast conditions (cloud base greater than 300 m above ground level) were best modeled as: N(Θ∗, ψ) = 0.149 + 0.084Θ∗ + 1.305e −2.5ψ while the translucent low cloud overcast conditions (cloud base less than 300 m above ground level) were best modeled as: N(Θ∗, ψ) = 0.080 + 0.058Θ∗ + 0.652e −2.1ψ . The obscured overcast sky condition (solar disk obscured) was best modeled as: N(Θ) = 0.441 [1 + 4.6cos Θ] /[1 + 4.6]. The unit of N for all equations is π Sr −1 , so that integration of each function over the sky hemisphere yields 1.0.These equations can be applied directly to the sky diffuse irradiance on the horizontal, I diff , to provide radiance distributions for the sky. Estimates of actual sky radiance distribution can be estimated from N a (Θ, ψ) = I diff N(Θ,

  9. Overlapping toxic effect of long term thallium exposure on white mustard (Sinapis alba L.) photosynthetic activity.

    Science.gov (United States)

    Mazur, Radosław; Sadowska, Monika; Kowalewska, Łucja; Abratowska, Agnieszka; Kalaji, Hazem M; Mostowska, Agnieszka; Garstka, Maciej; Krasnodębska-Ostręga, Beata

    2016-09-02

    Heavy metal exposure affect plant productivity by interfering, directly and indirectly, with photosynthetic reactions. The toxic effect of heavy metals on photosynthetic reactions has been reported in wide-ranging studies, however there is paucity of data in the literature concerning thallium (Tl) toxicity. Thallium is ubiquitous natural trace element and is considered the most toxic of heavy metals; however, some plant species, such as white mustard (Sinapis alba L.) are able to accumulate thallium at very high concentrations. In this study we identified the main sites of the photosynthetic process inhibited either directly or indirectly by thallium, and elucidated possible detoxification mechanisms in S. alba. We studied the toxicity of thallium in white mustard (S. alba) growing plants and demonstrated that tolerance of plants to thallium (the root test) decreased with the increasing Tl(I) ions concentration in culture media. The root growth of plants exposed to Tl at 100 μg L(-1) for 4 weeks was similar to that in control plants, while in plants grown with Tl at 1,000 μg L(-1) root growth was strongly inhibited. In leaves, toxic effect became gradually visible in response to increasing concentration of Tl (100 - 1,000 μg L(-1)) with discoloration spreading around main vascular bundles of the leaf blade; whereas leaf margins remained green. Subsequent structural analyses using chlorophyll fluorescence, microscopy, and pigment and protein analysis have revealed different effects of varying Tl concentrations on leaf tissue. At lower concentration partial rearrangement of the photosynthetic complexes was observed without significant changes in the chloroplast structure and the pigment and protein levels. At higher concentrations, the decrease of PSI and PSII quantum yields and massive oxidation of pigments was observed in discolored leaf areas, which contained high amount of Tl. Substantial decline of the photosystem core proteins and disorder of the

  10. Changes of Germination Properties, Photosynthetic Pigments and Anti Oxidant Enzymes Activity of Safflower as Affected by Drought and Salinity Stresses

    Directory of Open Access Journals (Sweden)

    A Sirousmehr

    2015-01-01

    Full Text Available To evaluate the effects of drought and salinity stresses on some germination characteristics, contents of photosynthetic pigments and antioxidant enzymes (CAT, APX and GPX in the leaves of safflower, a factorial experiment based on CRD was conducted during 2012 at both laboratory and greenhouse of Zabol University with four replications. To expose the plants to drought (0, -6 and -8 bars and salinity stresses (5, 10 and 15 ds.m-1 PEG 6000 and NaCl were used respectively. The results indicated that the effects of factors on germination percentage and rate, chlorophyll a and b contents and antioxidants enzymes activities were significant. The result of laboratory study revealed a reduction in percentage and speed of germination when plants exposed to negative osmotic potential. Photosynthetic pigments of plant leaves grown in greenhouse significantly decreased by increasing drought and salinity stresses. Increasing drought stress along with soluble salts changed the activity of some antioxidant enzymes. Enzymes’ activity of both CAT and GPX were increased when the plants expose to PEG drought stress, but decreased against the levels of salt stress. APX activity also increased due to drought stress. Interactive effects of drought×salinity stresses indicated that under lower stress GPX enzymes increased salinity, and under severe stress APX was highly increased. It means the production and activity of plant defensive system like these enzymes in recent tensions and leads to protect or make plants tolerate against oxidative stress induced by drought and salinity.

  11. Phospholipid transfer protein activity and incident type 2 diabetes mellitus

    NARCIS (Netherlands)

    Abbasi, Ali; Dallinga-Thie, Geesje M.; Dullaart, Robin P. F.

    2015-01-01

    Background: The plasma activity of phospholipid transfer protein (PLTP), which has multifaceted functions in lipoprotein metabolism and in inflammatory responses, is elevated in insulin resistant conditions. We determined the association of plasma PLTP activity with incident type 2 diabetes mellitus

  12. Effects of INH, DNP, 2,4-D and CMU on the photosynthetic activity of barley and maize plants

    International Nuclear Information System (INIS)

    Fernandez, J.; Prieto, M. P.

    1979-01-01

    Determinations of the rate of photosynthesis were made in barley and maize leaves treated with INH, DNP, 2,4-D or CMU. 1 ppm of the chemicals in nutritive solutions was absorbed by roots during 24 or 48 hours in both dark and light conditions. After this period, photosynthetic activity, compensation point and 14 C O 2 assimilation were determined. Results show that INH increases the rate of photosynthesis, DNP and 2,4-D do not alter it sensibly and CMU acts as a strong inhibitor of photosynthesis. Some possible applications for ths obtention of labelled compounds by biosynthesis are discussed. (Author) 87 refs

  13. Influence of exogenous urea on photosynthetic pigments, (14)CO 2 uptake, and urease activity in Elodea densa-environmental implications.

    Science.gov (United States)

    Maleva, Maria; Borisova, Galina; Chukina, Nadezda; Nekrasova, Galina; Prasad, M N V

    2013-09-01

    This paper analyzes the effect of exogenous urea in increased concentration gradient (0, 100, 500 and 1,000 mg L(-1)) on photosynthetic pigments (measured spectrophotometrically), uptake of (14)CO2 (using radioisotope), and urease activity (by measuring ammonia with Nessler's reagent) in leaves of Elodea densa Planch. We have observed that low concentration of urea (100 mg L(-1)) stimulates the accumulation of photosynthetic pigments and intensifies photosynthesis in E. densa, whereas high concentration (1,000 mg L(-1)) suppresses these processes. Urease activity increased by approximately 2.7 and 8 fold when exogenous urea concentrations were 100 and 500 mg L(-1), respectively. However, exogenous urea in high concentration (1,000 mg L(-1)) decreased urease activity by 1.5 fold compared to the control. The necessity of mitigating urea and other nitrogen-containing compounds (NH3 from urea) in water bodies has been discussed with emphasis on the potential for phytoremediation of urea using common water weed viz. E. densa.

  14. Scale dependence of absorption of photosynthetically active radiation in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Asner, G.P.; Wessman, C.A.; Archer, S.

    1998-01-01

    The fraction of photosynthetically active radiation absorbed by plant canopies (fAPAR) is a critical biophysical variable for extrapolating ecophysiological measurements from the leaf to landscape scale. Quantification of fAPAR determinants at the landscape level is needed to improve the interpretation of remote sensing data, to facilitate its use in constraining ecosystem process models, and to improve synoptic-scale links between carbon and nutrient cycles. Most canopy radiation budget studies have focused on light attenuation in plant canopies, with little regard for the importance of the scale-dependent biophysical and structural factors (e.g., leaf and stem optical properties, leaf and stem area, and extent of vegetation structural types) that ultimately determine fAPAR at canopy and landscape scales. Most studies have also assumed that nonphotosynthetic vegetation (litter and stems) contributes little to fAPAR. Using a combined field measurement and radiative transfer modeling approach, we quantified (a) the relative role of the leaf-, canopy-, and landscape-level factors that determine fAPAR in terrestrial ecosystems and (b) the magnitude of PAR absorption by grass litter and woody plant stems. Variability in full spectral-range (400–2500 nm) reflectance/transmittance and PAR (400–700 nm) absorption at the level of individual leaf, stem, and litter samples was quantified for a wide array of broadleaf arborescent and grass species along a 900-km north–south Texas savanna transect. Among woody growth forms, leaf reflectance and transmittance spectra were statistically comparable between populations, species within a genus, and functional types (deciduous vs. evergreen, legume vs. nonlegume). Within the grass life-form, spectral properties were statistically comparable between species and C 3 /C 4 physiologies. We found that tissue-level PAR absorption among species, genera, functional groups, and growth forms and between climatologically diverse regions

  15. Operational Estimates of Surface Albedo, Vegetation Photosynthetic Activity and Surface Structure: An Overview of the GVM/SAI Activities

    Science.gov (United States)

    Verstraete, M. M.; Pinty, B.; Gobron, N.; Widlowski, J.

    2001-05-01

    The GVM Unit of the SAI derives reliable, accurate, quantitative information on the state and evolution of the biosphere from remote sensing data, using state of the art techniques. This information is provided to various services of the European Commission in support of the verification of compliance with national and international treaties, protocols and conventions, and to the scientific community in the framework of defined collaborations. Estimates of land surface albedo have been obtained from an analysis of monospectral but multiangular observations from the geostationary Meteosat platform. An analysis of these results has shown the continental scale impact of human activities (in particular biomass burning over large areas). An extension of this approach to the more advanced Meteosat Second Generation platform, to be launched in 2002, will yield more and better products. High performance yet very fast algorithms have been derived to optimally assess the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) of live green vegetation, which largely controls the productivity of plants and therefore their ability to sequester atmospheric carbon dioxide. These algorithms, typically used with multispectral but monoangular sensors such as AVHRR, SeaWiFS, or VEGETATION, have now been further developed to take advantage of the high spatial resolution or multiangular views offered by modern sensors such as the MISR on NASA's Terra platform. Recent advances in radiation transfer modeling and scientific collaborations with the cloud community have opened new vistas on the possibility of characterizing the structure of ecosystems a the sub-pixel scale on the basis of multiangular data, and may lead to improved land cover classifications and new applications.

  16. An Assessment of the Incidence of Poverty Among Rural Active ...

    African Journals Online (AJOL)

    The study investigated the incidence and spatial distribution of poverty among rural active population in Mangu Local Government of Plateau State, Nigeria. The objectives of the study were to determine the socio-demographic and economic characteristics of the respondents; the incidence and spatial distribution of poverty ...

  17. Pro-active Management of Traffic Incidents Using Novel Technologies

    NARCIS (Netherlands)

    Nitsche, P.; Olstam, J.; Taylor, N.; Reinthaler, M.; Ponweiser, W.; Bernhardsson, V.; Mocanu, I.; Uittenbogaard, J.; Dam, E. van

    2016-01-01

    This paper presents the results of the assessment phase of the project PRIMA (Pro-Active Incident Management), where the benefits, costs and risks of novel traffic incident management techniques are investigated. The project targets the enhancement of current state-of-the-art measures for handling

  18. an assessment of the incidence of poverty among rural active

    African Journals Online (AJOL)

    Osondu

    2013-01-10

    Jan 10, 2013 ... Abstract. The study investigated the incidence and spatial distribution of poverty among rural active population in. Mangu Local Government of Plateau State, Nigeria. The objectives of the study were to determine the socio-demographic and economic characteristics of the respondents; the incidence and ...

  19. Ferredoxin-thioredoxin reductase: a catalytically active dithiol group links photoreduced ferredoxin to thioredoxin functional in photosynthetic enzyme regulation

    International Nuclear Information System (INIS)

    Droux, M.; Miginiac-Maslow, M.; Jacquot, J.P.; Gadal, P.; Crawford, N.A.; Kosower, N.S.; Buchanan, B.B.

    1987-01-01

    The mechanism by which the ferredoxin-thioredoxin system activates the target enzyme, NADP-malate dehydrogenase, was investigated by analyzing the sulfhydryl status of individual protein components with [ 14 C]iodoacetate and monobromobimane. The data indicate that ferredoxin-thioredoxin reductase (FTR)--an iron-sulfur enzyme present in oxygenic photosynthetic organisms--is the first member of a thiol chain that links light to enzyme regulation. FTR possesses a catalytically active dithiol group localized on the 13 kDa (similar) subunit, that occurs in all species investigated and accepts reducing equivalents from photoreduced ferredoxin and transfers them stoichiometrically to the disulfide form of thioredoxin m. The reduced thioredoxin m, in turn, reduces NADP-malate dehydrogenase, thereby converting it from an inactive (S-S) to an active (SH) form. The means by which FTR is able to combine electrons (from photoreduced ferredoxin) with protons (from the medium) to reduce its active disulfide group remains to be determined

  20. Spectral Bio-indicator Simulations for Tracking Photosynthetic Activities in a Corn Field

    Science.gov (United States)

    Cheng, Yen-Ben; Middleton, Elizabeth M.; Huemmrich, K. Fred; Zhang, Qingyuan; Corp, Lawrence; Campbell, Petya; Kustas, William

    2011-01-01

    Accurate assessment of vegetation canopy optical properties plays a critical role in monitoring natural and managed ecosystems under environmental changes. In this context, radiative transfer (RT) models simulating vegetation canopy reflectance have been demonstrated to be a powerful tool for understanding and estimating spectral bio-indicators. In this study, two narrow band spectroradiometers were utilized to acquire observations over corn canopies for two summers. These in situ spectral data were then used to validate a two-layer Markov chain-based canopy reflectance model for simulating the Photochemical Reflectance Index (PRI), which has been widely used in recent vegetation photosynthetic light use efficiency (LUE) studies. The in situ PRI derived from narrow band hyperspectral reflectance exhibited clear responses to: 1) viewing geometry which affects the asset of light environment; and 2) seasonal variation corresponding to the growth stage. The RT model (ACRM) successfully simulated the responses to the variable viewing geometry. The best simulations were obtained when the model was set to run in the two layer mode using the sunlit leaves as the upper layer and shaded leaves as the lower layer. Simulated PRI values yielded much better correlations to in situ observations when the cornfield was dominated by green foliage during the early growth, vegetative and reproductive stages (r = 0.78 to 0.86) than in the later senescent stage (r = 0.65). Further sensitivity analyses were conducted to show the important influences of leaf area index (LAI) and the sunlit/shaded ratio on PRI observations.

  1. Effect of diurnal photosynthetic activity on the fine structure of amylopectin from normal and waxy barley starch

    DEFF Research Database (Denmark)

    Goldstein, Avi; Annor, George; Blennow, Andreas

    2017-01-01

    The impact of diurnal photosynthetic activity on the fine structure of the amylopectin fraction of starch synthesized by normal barley (NBS) and waxy barley (WBS), the latter completely devoid of amylose biosynthesis, was determined following the cultivation under normal diurnal or constant light...... growing conditions. The amylopectin fine structures were analysed by characterizing its unit chain length profiles after enzymatic debranching as well as its φ,β-limit dextrins and its clusters and building blocks after their partial and complete hydrolysis with α-amylase from Bacillus amyloliquefaciens...... under constant light. Our data demonstrate that the diurnal light regime influences the fine structure of the amylopectin component both in amylose and non-amylose starch granules....

  2. Phospholipid transfer protein activity and incident type 2 diabetes mellitus

    NARCIS (Netherlands)

    Abbasi, Ali; Dallinga-Thie, Geesje M.; Dullaart, Robin P. F.

    2015-01-01

    The plasma activity of phospholipid transfer protein (PLTP), which has multifaceted functions in lipoprotein metabolism and in inflammatory responses, is elevated in insulin resistant conditions. We determined the association of plasma PLTP activity with incident type 2 diabetes mellitus (T2DM).

  3. Active lifestyle protects against incident low back pain in seniors

    DEFF Research Database (Denmark)

    Hartvigsen, Jan; Christensen, Kaare

    2007-01-01

    STUDY DESIGN: Prospective cohort study of twins. OBJECTIVES: To investigate associations between physical activity, physical function, and incident low back pain (LBP) in an elderly population. SUMMARY OF BACKGROUND DATA: The relationship between an active lifestyle and LBP in seniors is unknown...

  4. Elevated temperature altered photosynthetic products in wheat seedlings and organic compounds and biological activity in rhizopshere soil under cadmium stress.

    Science.gov (United States)

    Jia, Xia; Zhao, YongHua; Wang, WenKe; He, Yunhua

    2015-09-23

    The objective of this study was to investigate the effects of slightly elevated atmospheric temperature in the spring on photosynthetic products in wheat seedlings and on organic compounds and biological activity in rhizosphere soil under cadmium (Cd) stress. Elevated temperature was associated with increased soluble sugars, reducing sugars, starch, and total sugars, and with decreased amino acids in wheat seedlings under Cd stress. Elevated temperature improved total soluble sugars, free amino acids, soluble phenolic acids, and organic acids in rhizosphere soil under Cd stress. The activity of amylase, phenol oxidase, invertase, β-glucosidase, and l-asparaginase in rhizosphere soil was significantly improved by elevated temperature under Cd stress; while cellulase, neutral phosphatase, and urease activity significantly decreased. Elevated temperature significantly improved bacteria, fungi, actinomycetes, and total microorganisms abundance and fluorescein diacetate activity under Cd stress. In conclusion, slightly elevated atmospheric temperature in the spring improved the carbohydrate levels in wheat seedlings and organic compounds and biological activity in rhizosphere soil under Cd stress in the short term. In addition, elevated atmospheric temperature in the spring stimulated available Cd by affecting pH, DOC, phenolic acids, and organic acids in rhizosphere soil, which resulted in the improvement of the Cd uptake by wheat seedlings.

  5. Photosynthetic Pigments in Diatoms

    OpenAIRE

    Kuczynska, Paulina; Jemiola-Rzeminska, Malgorzata; Strzalka, Kazimierz

    2015-01-01

    Photosynthetic pigments are bioactive compounds of great importance for the food, cosmetic, and pharmaceutical industries. They are not only responsible for capturing solar energy to carry out photosynthesis, but also play a role in photoprotective processes and display antioxidant activity, all of which contribute to effective biomass and oxygen production. Diatoms are organisms of a distinct pigment composition, substantially different from that present in plants. Apart from light-harvestin...

  6. Ferredoxin-thioredoxin reductase: a catalytically active dithiol group links photoreduced ferredoxin to thioredoxin functional in photosynthetic enzyme regulation

    Energy Technology Data Exchange (ETDEWEB)

    Droux, M.; Miginiac-Maslow, M.; Jacquot, J.P.; Gadal, P.; Crawford, N.A.; Kosower, N.S.; Buchanan, B.B.

    1987-07-01

    The mechanism by which the ferredoxin-thioredoxin system activates the target enzyme, NADP-malate dehydrogenase, was investigated by analyzing the sulfhydryl status of individual protein components with (/sup 14/C)iodoacetate and monobromobimane. The data indicate that ferredoxin-thioredoxin reductase (FTR)--an iron-sulfur enzyme present in oxygenic photosynthetic organisms--is the first member of a thiol chain that links light to enzyme regulation. FTR possesses a catalytically active dithiol group localized on the 13 kDa (similar) subunit, that occurs in all species investigated and accepts reducing equivalents from photoreduced ferredoxin and transfers them stoichiometrically to the disulfide form of thioredoxin m. The reduced thioredoxin m, in turn, reduces NADP-malate dehydrogenase, thereby converting it from an inactive (S-S) to an active (SH) form. The means by which FTR is able to combine electrons (from photoreduced ferredoxin) with protons (from the medium) to reduce its active disulfide group remains to be determined.

  7. Active Full-Shell Grazing-Incidence Optics

    Science.gov (United States)

    Davis, Jacqueline M.; Elsner, Ronald F.; Ramsey, Brian D.; O'Dell, Stephen L.; Kolodziejczak, Jeffery; Weisskopf, Martin C.; Gubarev, Mikhail V.

    2016-01-01

    MSFC has a long history of developing full-shell grazing-incidence x-ray optics for both narrow (pointed) and wide field (surveying) applications. The concept presented in this paper shows the potential to use active optics to switch between narrow and wide-field geometries, while maintaining large effective area and high angular resolution. In addition, active optics has the potential to reduce errors due to mounting and manufacturing lightweight optics. The design presented corrects low spatial frequency error and has significantly fewer actuators than other concepts presented thus far in the field of active x-ray optics. Using a finite element model, influence functions are calculated using active components on a full-shell grazing-incidence optic. Next, the ability of the active optic to effect a change of optical prescription and to correct for errors due to manufacturing and mounting is modeled.

  8. Photosynthetic gene expression in higher plants.

    Science.gov (United States)

    Berry, James O; Yerramsetty, Pradeep; Zielinski, Amy M; Mure, Christopher M

    2013-11-01

    Within the chloroplasts of higher plants and algae, photosynthesis converts light into biological energy, fueling the assimilation of atmospheric carbon dioxide into biologically useful molecules. Two major steps, photosynthetic electron transport and the Calvin-Benson cycle, require many gene products encoded from chloroplast as well as nuclear genomes. The expression of genes in both cellular compartments is highly dynamic and influenced by a diverse range of factors. Light is the primary environmental determinant of photosynthetic gene expression. Working through photoreceptors such as phytochrome, light regulates photosynthetic genes at transcriptional and posttranscriptional levels. Other processes that affect photosynthetic gene expression include photosynthetic activity, development, and biotic and abiotic stress. Anterograde (from nucleus to chloroplast) and retrograde (from chloroplast to nucleus) signaling insures the highly coordinated expression of the many photosynthetic genes between these different compartments. Anterograde signaling incorporates nuclear-encoded transcriptional and posttranscriptional regulators, such as sigma factors and RNA-binding proteins, respectively. Retrograde signaling utilizes photosynthetic processes such as photosynthetic electron transport and redox signaling to influence the expression of photosynthetic genes in the nucleus. The basic C3 photosynthetic pathway serves as the default form used by most of the plant species on earth. High temperature and water stress associated with arid environments have led to the development of specialized C4 and CAM photosynthesis, which evolved as modifications of the basic default expression program. The goal of this article is to explain and summarize the many gene expression and regulatory processes that work together to support photosynthetic function in plants.

  9. Effects of fatty acid activation on photosynthetic production of fatty acid-based biofuels in Synechocystis sp. PCC6803

    Directory of Open Access Journals (Sweden)

    Gao Qianqian

    2012-03-01

    Full Text Available Abstract Background Direct conversion of solar energy and carbon dioxide to drop in fuel molecules in a single biological system can be achieved from fatty acid-based biofuels such as fatty alcohols and alkanes. These molecules have similar properties to fossil fuels but can be produced by photosynthetic cyanobacteria. Results Synechocystis sp. PCC6803 mutant strains containing either overexpression or deletion of the slr1609 gene, which encodes an acyl-ACP synthetase (AAS, have been constructed. The complete segregation and deletion in all mutant strains was confirmed by PCR analysis. Blocking fatty acid activation by deleting slr1609 gene in wild-type Synechocystis sp. PCC6803 led to a doubling of the amount of free fatty acids and a decrease of alkane production by up to 90 percent. Overexpression of slr1609 gene in the wild-type Synechocystis sp. PCC6803 had no effect on the production of either free fatty acids or alkanes. Overexpression or deletion of slr1609 gene in the Synechocystis sp. PCC6803 mutant strain with the capability of making fatty alcohols by genetically introducing fatty acyl-CoA reductase respectively enhanced or reduced fatty alcohol production by 60 percent. Conclusions Fatty acid activation functionalized by the slr1609 gene is metabolically crucial for biosynthesis of fatty acid derivatives in Synechocystis sp. PCC6803. It is necessary but not sufficient for efficient production of alkanes. Fatty alcohol production can be significantly improved by the overexpression of slr1609 gene.

  10. Nitrate reductase and photosynthetic activities of wheat and their relationship with plant productivity under soil water deficit conditions (abstract)

    International Nuclear Information System (INIS)

    Ashraf, M.Y.; Sarwar, G.; Hussain, F.

    2005-01-01

    Experiments were conducted in lysimeters with wheat during two consecutive years. The first year experiment comprised of eight wheat genotypes with four water stress treatments, i.e. normal irrigation, pre-anthesis drought, post-anthesis drought and terminal drought, with four replications. The results showed that yield and yield parameters reduced with the severity of drought in all wheat lines. However, wheat lines Chakwal-86, DS-4 and Barani-83 had comparatively higher yield and yield components than others. The maximum reduction in all parameters was under terminal drought. The difference between pre- and post-anthesis drought was nonsignificant, particularly for grain yield. The second experiment was conducted with four wheat lines: two were tolerant (Chakwal-86 and DS-4) and two susceptible (Pavon and DS-17) under similar environments with same treatments to study the photosynthetic efficiency, nitrogen metabolism and their relationship with plant productivity (yield). The results showed that leaf area, transpiration, dry matter accumulation and nitrate reductase activity were reduced while diffusive resistance and total amino acids increased in all the wheat lines under water deficit conditions. The relationship between yield and leaf area, transpiration, dry matter accumulation and nitrate reductase activity was positive. The overall results showed that wheat lines Chakwal-86 and DS-4 showed better performance than others. (author)

  11. Measures and modelling of PAR (photosynthetically-active radiation) for the Northeast of Brazil; Medidas e modelagem da radiacao PAR (photosynthetically-active radiation) para o nordeste do Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Tiba, Chigueru; Leal, Sergio da S.A. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear], e-mail: tiba@rce.neoline.com.br

    2004-07-01

    Photosynthetically active solar radiation, known by its acronym in the English language as PAR, is the principal driving force of innumerable biological and physical processes related to biomass production, such as, the evolution of vegetal covering, agricultural productivity, and countless environment aspects, among others. Unfortunately in Brazil and particularly in the Northeast of Brazil, the PAR radiation measures are not a routine part of meteorological station measures, and therefore are still rarer than solar irradiation measures. In this context, a station was installed in Recife, Pernambuco in 2003, to carry out simultaneous measures of daily solar irradiation and PAR irradiation, which permits the modelling and valuation of the relationship between these two parameters and thus makes the estimation of PAR radiation possible, where there used to be only information on solar irradiation. Three others stations are being installed, one on Fernando de Noronha-PE, another in Pesqueira-PE, and the other in Xingo-SE, which complete a group of 4 between Latitudes 8 deg and 10 deg South and Longitudes 34 deg to 38 deg West, each having differentiated Equatorial Climates: island maritime, continental maritime, sylvan (Agreste) and semi-arid. (author)

  12. Changes in Leaf Anatomical Traits Enhanced Photosynthetic Activity of Soybean Grown in Hydroponics with Plant Growth-Promoting Microorganisms

    Science.gov (United States)

    Paradiso, Roberta; Arena, Carmen; De Micco, Veronica; Giordano, Maria; Aronne, Giovanna; De Pascale, Stefania

    2017-01-01

    The use of hydroponic systems for cultivation in controlled climatic conditions and the selection of suitable genotypes for the specific environment help improving crop growth and yield. We hypothesized that plant performance in hydroponics could be further maximized by exploiting the action of plant growth-promoting organisms (PGPMs). However, the effects of PGPMs on plant physiology have been scarcely investigated in hydroponics. Within a series of experiments aimed to identify the best protocol for hydroponic cultivation of soybean [Glycine max (L.) Merr.], we evaluated the effects of a PGPMs mix, containing bacteria, yeasts, mycorrhiza and trichoderma beneficial species on leaf anatomy, photosynthetic activity and plant growth of soybean cv. ‘Pr91m10’ in closed nutrient film technique (NFT). Plants were grown in a growth chamber under semi-aseptic conditions and inoculated at seed, seedling and plant stages, and compared to non-inoculated (control) plants. Light and epi-fluorescence microscopy analyses showed that leaves of inoculated plants had higher density of smaller stomata (297 vs. 247 n/mm2), thicker palisade parenchyma (95.0 vs. 85.8 μm), and larger intercellular spaces in the mesophyll (57.5% vs. 52.2%), compared to non-inoculated plants. The modifications in leaf functional anatomical traits affected gas exchanges; in fact starting from the reproductive phase, the rate of leaf net photosynthesis (NP) was higher in inoculated compared to control plants (8.69 vs. 6.13 μmol CO2 m-2 s-1 at the beginning of flowering). These data are consistent with the better maximal PSII photochemical efficiency observed in inoculated plants (0.807 vs. 0.784 in control); conversely no difference in leaf chlorophyll content was found. The PGPM-induced changes in leaf structure and photosynthesis lead to an improvement of plant growth (+29.9% in plant leaf area) and seed yield (+36.9%) compared to control. Our results confirm that PGPMs may confer benefits in

  13. Changes in Leaf Anatomical Traits Enhanced Photosynthetic Activity of Soybean Grown in Hydroponics with Plant Growth-Promoting Microorganisms

    Directory of Open Access Journals (Sweden)

    Roberta Paradiso

    2017-05-01

    Full Text Available The use of hydroponic systems for cultivation in controlled climatic conditions and the selection of suitable genotypes for the specific environment help improving crop growth and yield. We hypothesized that plant performance in hydroponics could be further maximized by exploiting the action of plant growth-promoting organisms (PGPMs. However, the effects of PGPMs on plant physiology have been scarcely investigated in hydroponics. Within a series of experiments aimed to identify the best protocol for hydroponic cultivation of soybean [Glycine max (L. Merr.], we evaluated the effects of a PGPMs mix, containing bacteria, yeasts, mycorrhiza and trichoderma beneficial species on leaf anatomy, photosynthetic activity and plant growth of soybean cv. ‘Pr91m10’ in closed nutrient film technique (NFT. Plants were grown in a growth chamber under semi-aseptic conditions and inoculated at seed, seedling and plant stages, and compared to non-inoculated (control plants. Light and epi-fluorescence microscopy analyses showed that leaves of inoculated plants had higher density of smaller stomata (297 vs. 247 n/mm2, thicker palisade parenchyma (95.0 vs. 85.8 μm, and larger intercellular spaces in the mesophyll (57.5% vs. 52.2%, compared to non-inoculated plants. The modifications in leaf functional anatomical traits affected gas exchanges; in fact starting from the reproductive phase, the rate of leaf net photosynthesis (NP was higher in inoculated compared to control plants (8.69 vs. 6.13 μmol CO2 m-2 s-1 at the beginning of flowering. These data are consistent with the better maximal PSII photochemical efficiency observed in inoculated plants (0.807 vs. 0.784 in control; conversely no difference in leaf chlorophyll content was found. The PGPM-induced changes in leaf structure and photosynthesis lead to an improvement of plant growth (+29.9% in plant leaf area and seed yield (+36.9% compared to control. Our results confirm that PGPMs may confer benefits in

  14. Nitrate Activation of Cytosolic Protein Kinases Diverts Photosynthetic Carbon from Sucrose to Amino Acid Biosynthesis

    Science.gov (United States)

    Champigny, Marie-Louise; Foyer, Christine

    1992-01-01

    The regulation of carbon partitioning between carbohydrates (principally sucrose) and amino acids has been only poorly characterized in higher plants. The hypothesis that the pathway of sucrose and amino acid biosynthesis compete for carbon skeletons and energy is widely accepted. In this review, we suggest a mechanism involving the regulation of cytosolic protein kinases whereby the flow of carbon is regulated at the level of partitioning between the pathways of carbohydrate and nitrogen metabolism via the covalent modulation of component enzymes. The addition of nitrate to wheat seedlings (Triticum aestivum) grown in the absence of exogenous nitrogen has a dramatic, if transient, impact on sucrose formation and on the activities of sucrose phosphate synthase (which is inactivated) and phosphoenolpyruvate carboxylase (which is activated). The activities of these two enzymes are modulated by protein phosphorylation in response to the addition of nitrate, but they respond in an inverse fashion. Sucrose phosphate synthase in inactivated and phosphoenolpyruvate carboxylase is activated. Nitrate functions as a signal metabolite activating the cytosolic protein kinase, thereby modulating the activities of at least two of the key enzymes in assimilate partitioning and redirecting the flow of carbon away from sucrose biosynthesis toward amino acid synthesis. PMID:16653003

  15. Elevated atmospheric CO2 affected photosynthetic products in wheat seedlings and biological activity in rhizosphere soil under cadmium stress.

    Science.gov (United States)

    Jia, Xia; Liu, Tuo; Zhao, Yonghua; He, Yunhua; Yang, Mingyan

    2016-01-01

    The objective of this study was to investigate the effects of elevated CO2 (700 ± 23 μmol mol(-1)) on photosynthetic products in wheat seedlings and on organic compounds and biological activity in rhizosphere soil under cadmium (Cd) stress. Elevated CO2 was associated with decreased quantities of reducing sugars, starch, and soluble amino acids, and with increased quantities of soluble sugars, total sugars, and soluble proteins in wheat seedlings under Cd stress. The contents of total soluble sugars, total free amino acids, total soluble phenolic acids, and total organic acids in the rhizosphere soil under Cd stress were improved by elevated CO2. Compared to Cd stress alone, the activity of amylase, phenol oxidase, urease, L-asparaginase, β-glucosidase, neutral phosphatase, and fluorescein diacetate increased under elevated CO2 in combination with Cd stress; only cellulase activity decreased. Bacterial abundance in rhizosphere soil was stimulated by elevated CO2 at low Cd concentrations (1.31-5.31 mg Cd kg(-1) dry soil). Actinomycetes, total microbial abundance, and fungi decreased under the combined conditions at 5.31-10.31 mg Cd kg(-1) dry soil. In conclusion, increased production of soluble sugars, total sugars, and proteins in wheat seedlings under elevated CO2 + Cd stress led to greater quantities of organic compounds in the rhizosphere soil relative to seedlings grown under Cd stress only. Elevated CO2 concentrations could moderate the effects of heavy metal pollution on enzyme activity and microorganism abundance in rhizosphere soils, thus improving soil fertility and the microecological rhizosphere environment of wheat under Cd stress.

  16. Continuous high and low temperature induced a decrease of photosynthetic activity and changes in the diurnal fluctuations of organic acids in Opuntia streptacantha.

    Directory of Open Access Journals (Sweden)

    Zaida Zarely Ojeda-Pérez

    Full Text Available Opuntia plants grow naturally in areas where temperatures are extreme and highly variable in the day during the entire year. These plants survive through different adaptations to respond to adverse environmental conditions. Despite this capability, it is unknown how CAM photosynthetic activity and growth in Opuntia plantlets is affected by constant heat or cold. Therefore, the main objective of this research was to evaluate the short-term effect of high (40°C and low (4°C continuous temperatures on the photosynthetic efficiency, the organic acid content (malic acid and the relative growth rate (RGR in seven-month-old Opuntia streptacantha plantlets during 5, 10, and 15 days. Chlorophyll fluorescence analysis allowed us to determine that high temperatures negatively impact the photosynthetic efficiency of O. streptacantha plantlets, which exhibited the lowest values of maximum quantum efficiency of the photosystem II (Fv/Fm = 52%, Fv/F0 = 85%, operational quantum yield of PS (ΦPSII = 65% and relative electron transport rate (rETR = 65%, as well as highest values of basal fluorescence (F0 = 226% during 15 days of treatment. Similarly, low temperatures decreased Fv/Fm (16%, Fv/F0 (50%, ΦPSII and rETR (16%. High temperatures also decreased nocturnal acidification in approximately 34-50%, whereas low temperatures increased it by 30-36%. Additionally, both continuous temperatures affected drastically diurnal consumption of malic acid, which was related to a significant RGR inhibition, where the specific photosynthetic structure area component was the most affected. Our results allowed determining that, despite the high tolerance to extreme temperatures described for Opuntia plants, young individuals of O. streptacantha suffered photosynthetic impairment that led to the inhibition of their growth. Thus, the main findings reported in this study can help to predict the potential impact of climatic change on the establishment and survival of succulent

  17. Continuous high and low temperature induced a decrease of photosynthetic activity and changes in the diurnal fluctuations of organic acids in Opuntia streptacantha.

    Science.gov (United States)

    Ojeda-Pérez, Zaida Zarely; Jiménez-Bremont, Juan Francisco; Delgado-Sánchez, Pablo

    2017-01-01

    Opuntia plants grow naturally in areas where temperatures are extreme and highly variable in the day during the entire year. These plants survive through different adaptations to respond to adverse environmental conditions. Despite this capability, it is unknown how CAM photosynthetic activity and growth in Opuntia plantlets is affected by constant heat or cold. Therefore, the main objective of this research was to evaluate the short-term effect of high (40°C) and low (4°C) continuous temperatures on the photosynthetic efficiency, the organic acid content (malic acid) and the relative growth rate (RGR) in seven-month-old Opuntia streptacantha plantlets during 5, 10, and 15 days. Chlorophyll fluorescence analysis allowed us to determine that high temperatures negatively impact the photosynthetic efficiency of O. streptacantha plantlets, which exhibited the lowest values of maximum quantum efficiency of the photosystem II (Fv/Fm = 52%, Fv/F0 = 85%), operational quantum yield of PS (ΦPSII = 65%) and relative electron transport rate (rETR = 65%), as well as highest values of basal fluorescence (F0 = 226%) during 15 days of treatment. Similarly, low temperatures decreased Fv/Fm (16%), Fv/F0 (50%), ΦPSII and rETR (16%). High temperatures also decreased nocturnal acidification in approximately 34-50%, whereas low temperatures increased it by 30-36%. Additionally, both continuous temperatures affected drastically diurnal consumption of malic acid, which was related to a significant RGR inhibition, where the specific photosynthetic structure area component was the most affected. Our results allowed determining that, despite the high tolerance to extreme temperatures described for Opuntia plants, young individuals of O. streptacantha suffered photosynthetic impairment that led to the inhibition of their growth. Thus, the main findings reported in this study can help to predict the potential impact of climatic change on the establishment and survival of succulent species

  18. Effect of smoke and clouds on the transmissivity of photosynthetically active radiation inside the canopy

    NARCIS (Netherlands)

    Yamasoe, M.A.; Randow, von C.; Manzi, A.O.; Schafer, J.S.; Eck, T.F.; Holben, B.N.

    2006-01-01

    Biomass burning activities emit high concentrations of aerosol particles to the atmosphere. Such particles can interact with solar radiation, decreasing the amount of light reaching the surface and increasing the fraction of diffuse radiation through scattering processes, and thus has implications

  19. [Effects of supplemental irrigation based on soil moisture on photosynthetic characteristics and enzyme activity of flan leaf in wheat].

    Science.gov (United States)

    He, Jian-ning; Shi, Yu; Zhao, Jun-ye; Zhang, Yong-li; Yu, Zhen-wen

    2015-12-01

    A field experiment was conducted to study the effects of supplemental irrigation based on soil moisture on the photosynthesis characteristics and enzyme activity of flag leaf using the wheat cultivar Jimai 20. Three irrigation treatments were designed with target soil moisture of 65% (W₆₅), 70% (W₇₀) and 75% (W₇₅) both at jointing and anthesis stages. Zero-irrigation ( CK) was used as the control. The results showed that the net photosynthetic rate (Pn) of flag leaf in treatment W₇₀ was dramatically higher than in other treatments from 14 to 21 days after anthesis, as well as sucrose content and sucrose phosphate synthase (SPS) activity. The dry matter mass per area of W₇₀ was higher than that of W₆₅ and CK, and was not significantly different from that of W₇₅. The single stem mass of W₇₀ was higher than that of the other treatments. The activities of superoxide dismutase (SOD) and catalase (CAT) and the soluble protein concentration in flag leaf of W₇₀ were significantly higher than in other treatments from 14 to 28 days after anthesis. The malondialdehyde (MDA) content of W₇₀ was lower than that of W₆₅ and CK, and was not significantly different from that of W₇₅ from 14 to 21 days after anthesis. Grain yields of W₇₀ were 8941.4 and 9125.4 kg · hm⁻² in the 2012-2013 and 2013-2014 wheat growing seasons, showing no significant difference with those of W₇₅, but obviously higher than those of W₆₅ and CK. And the water use efficiency (WUE) of W₇₀ was the highest. Considering grain yield and WUE, maintaining the relative soil water content at 70% by supplemental irrigation both at jointing and anthesis stages was the best treatment.

  20. Active lifestyle protects against incident low back pain in seniors

    DEFF Research Database (Denmark)

    Hartvigsen, Jan; Christensen, Kaare

    2007-01-01

    . METHODS: Participants in the population-based Longitudinal Study of Aging Danish Twins free from LBP at baseline (no LBP during the past month) were included, and interview data on physical activity, overall physical function, and LBP at baseline and follow-up were obtained. Associations between levels...... or lower than average physical function at baseline. Absolute risk for LBP was also calculated for participants based on whether they remained active or inactive between baseline and follow-up or changed activity level. RESULTS: A total of 1387 persons aged 70-100 at baseline were included in the analyses......STUDY DESIGN: Prospective cohort study of twins. OBJECTIVES: To investigate associations between physical activity, physical function, and incident low back pain (LBP) in an elderly population. SUMMARY OF BACKGROUND DATA: The relationship between an active lifestyle and LBP in seniors is unknown...

  1. Phycobilisome-thylakoid topography on photosynthetically active vesicles of Porphyridium cruentum

    Energy Technology Data Exchange (ETDEWEB)

    Dilworth, M.F.; Gantt, E.

    1981-04-01

    Conditions are described for isolating functional phycobilisome-thylakoid vesicles from the red alga Porphyridium cruentum. They required ferricyanide as an oxidant and had O/sub 2/ evolution rates higher than whole cells. Energy transfer to photosystem II chlorophyll was evident from a high F695 nanometer (-196 C) emission peak. In electron micrographs of negatively stained material, the active thylakoid vesicles were found covered by closely spaced phycobilisomes on their external surface. The phycobilisome number in negatively stained vesicles was 450 per square micrometer, which was in the same range as the 400 per square micrometer observed in surface sections.

  2. Dark/light modulation of ribulose bisphosphate carboxylase activity in plants from different photosynthetic categories

    Energy Technology Data Exchange (ETDEWEB)

    Vu, J.C.V.; Allen, L.H. Jr.; Bowes, G.

    1984-11-01

    Ribulose bisphosphate carboxylase/oxygenase (RuBPCase) from several plants had substantially greater activity in extracts from light-exposed leaves than dark leaves, even when the extracts were incubated in vitro with saturating HCO/sub 3//sup -/ and Mg/sup 2 +/ concentrations. This occurred in Glycine max, Lycopersicon esculentum, Nicotiana tabacum, Panicum bisulcatum, and P. hylaeicum (C/sub 3/); P. maximum (C/sub 4/ phosphoenolpyruvate carboxykinase); P. milioides (C/sub 3//C/sub 4/); and Bromelia pinguin and Ananas comosus (Crassulacean acid metabolism). Little or no difference between light and dark leaf extracts of RuBPCase was observed in Triticum aestivum (C/sub 3/); P. miliaceum (C/sub 4/ NAD malic enzyme); Zea mays and Sorghum bicolor (C/sub 4/ NADP malic enzyme); Moricandia arvensis (C/sub 3//C/sub 4/); and Hydrilla verticillata (submersed aquatic macrophyte). It is concluded that, in many plants, especially Crassulacean acid metabolism and C/sub 3/ species, a large fraction of ribulose-1,5-bisphosphate carboxylase/oxygenase in the dark is in an inactivatable state that cannot respond to CO/sub 2/ and Mg/sup 2 +/ activation, but which can be converted to an activatable state upon exposure of the leaf to light. 16 references, 2 tables.

  3. LIGHT-REGULATED PHOTOSYNTHETIC GENE EXPRESSION AND PHOSPHORIBULOKINASE ENZYME ACTIVITY IN THE HETEROKONT ALGA VAUCHERIA LITOREA (XANTHOPHYCEAE) AND ITS SYMBIOTIC MOLLUSKAN PARTNER ELYSIA CHLOROTICA (GASTROPODA)(1).

    Science.gov (United States)

    Soule, Kara M; Rumpho, Mary E

    2012-04-01

    Photosynthesis is composed of tightly coupled reactions requiring finely tuned nucleocytosolic-plastid interaction. Herein, we examined the influence of light on select photosynthetic gene expression and enzyme activity in the plastid-containing mollusk (sea slug) Elysia chlorotica and its heterokont algal prey Vaucheria litorea C. Agardh. Transcript levels of nuclear photosynthetic genes (psbO and prk) were significantly lower in E. chlorotica compared with V. litorea, whereas plastid photosynthesis genes (psaA and rbcL) were more comparable, although still lower in the animal. None of the genes responded similarly to changes in light conditions over a 24 h period in the sea slug compared with the alga. Activity of the nuclear-encoded photosynthetic enzyme phosphoribulokinase (PRK) exhibited redox regulation in vitro in crude extracts of both organisms sequentially treated with oxidizing and reducing agents. However, PRK was differentially affected in vivo by redox and light versus dark treatment in V. litorea, but not in E. chlorotica. Overall, these results support the active transcription of algal nuclear and plastid genes in E. chlorotica, as well as sustained activity of a nuclear-encoded plastid enzyme, even after several months of starvation (absence of algal prey). The apparent absence of tight transcriptional regulation and redox control suggests that essential nuclear-encoded regulatory factors in V. litorea are probably not present in the sea slug. These findings are discussed relative to light regulation of photosynthetic gene expression in the green and red algal lineages and in the context of the sea slug/algal plastid kleptoplastic association. © 2012 Phycological Society of America.

  4. On the ultrasonic irradiation in the photosynthetic activity of aquatic lirium (Eichornia crassipes)

    International Nuclear Information System (INIS)

    Calderon, A.; Cardona, A.; Juarez G, A. G.; Marin, E.; Munoz H, R. A.; Diaz G, J. A.

    2012-10-01

    We report, for the first time, the application of the photoacoustic technique for monitoring the photosynthesis evolution in aquatic lirium (Eichornia crassipes), before and after it was exposed to ultrasonic irradiations. We obtained the disappearance of the phototobaric contribution in the Pa signal measured for the irradiated samples with ultrasound of 17 khz, and therefore of a possible damage in the centers producing the photosynthesis, due to the irradiation. These results show the utility of the ultrasonic irradiation, as well as, of the photosynthesis monitoring by means of the photoacoustic technique, for the elaboration and establishment of methodologies in the control of this aquatic plant, whose propagation causes many consequences extremely unfavorable for the environment, as well as for the diverse human activities that are developed in the bodies of water in the tropical and sub-tropical regions of the world. (Author)

  5. Visualization of water usage and photosynthetic activity of street trees exposed to 2 ppm of SO2-A combined evaluation by cold neutron and chlorophyll fluorescence imaging

    International Nuclear Information System (INIS)

    Matsushima, U.; Kardjilov, N.; Hilger, A.; Manke, I.; Shono, H.; Herppich, W.B.

    2009-01-01

    Photosynthetic efficacy and auto-exhaust-fume resistance of street trees were evaluated by cold neutron radiography (CNR) with D 2 O tracer and chlorophyll fluorescence (CF) imaging. With these techniques, information on the responses of water usage and photosynthetic activity of plants exposed to simulate toxic auto-exhaust fumes (2 ppm SO 2 in air) were obtained. Branches of hibiscus trees were detached, placed into a tub with aerated water and used for the experiments after rooting. A CF image was taken before SO 2 was applied for 1 h. During the experiment, CNR and CF imaging were conduced. H 2 O and D 2 O in the plant container were exchanged every 30 min to observe water uptake. D 2 O tracer clearly showed water uptake into the hibiscus stem during each treatment. When the atmosphere was changed from simulated auto-exhaust fumes to normal air again, the amount of D 2 O and, hence, water uptake increased. CF imaging was well suited to evaluate the effects of SO 2 as simulated toxic auto-exhaust fumes on plants. The maximum photochemical efficiency (F v /F m ), a sensitive indicator of the efficacy and the integrity of plants' photosynthesis, immediately dropped by 30% after supplying the simulated auto-exhaust fumes. This indicates that toxic auto-exhaust fumes negatively affected the photosynthetic activity of hibiscus leaves. Simultaneous CNR and CF imaging successfully visualized variations of photosynthetic activity and water uptake in the sample. Thus, this combination method was effective to non-destructive analyze the physiological status of plants.

  6. Production and photosynthetic activity of Mimosa Verde and Mimosa Roxa lettuce in two farming systems

    Directory of Open Access Journals (Sweden)

    Aline Mabel Rosa

    2014-08-01

    Full Text Available Lettuce (Lactuca sativa L. is the most commonly consumed leaf vegetable in the Brazilian diet, and it is a good source of vitamins and minerals. It is widely grown in the conventional farming system. However, the hydroponic farming system has been gaining importance in the market, wining confidence from consumers, who are becoming increasingly more demanding on food quality. The objective of this study was to evaluate the performance of two lettuce cultivars on hydroponic and conventional farming systems for the production of fresh mass (FM and dry mass (DM, photosynthesis, contents of chlorophyll and anthocyanin. The following two experiments were carried out: hydroponics farming (HF and conventional farming (CF, performed in protect and unprotect environments, respectively, in Florianópolis, SC. Mimosa Verde cultivar (MV showed greater fresh mass than Mimosa Roxa (MR, in both farming systems and the two cultivars presented better performance in the hydroponic system (287.7 g MV and 139.1 g MR than the conventional system (129.7 g MV and 111.8 g MR. Mimosa Verde cultivar presented lower average contents of total chlorophyll (7.7 mg g-¹ FM than Mimosa Roxa (11.8 mg g-¹FM, and both cultivars displayed higher means for this variable in the hydroponic farming system. Mimosa Roxa presented higher contents of anthocyanin in the conventional system (88.24 mg g-¹ FM than the ones in the hydroponic system (36.89 mg g-¹ FM. The best results for CO2 net assimilation rate regarded to photosyntheticaly active photon flux density were found in the hydroponic system, for both lettuce cultivars. Variation in the contents of chlorophyll were also found. Those variations were higher in the protected system than in the hydroponic system and contents of anthocyanin were higher in the conventional system.

  7. Far-red enrichment and photosynthetically active radiation level influence leaf senescence in field-grown sunflower

    International Nuclear Information System (INIS)

    Rousseaux, M.C.; Hall, A.J.; Sánchez, R.A.

    1996-01-01

    Basal leaves frequently senesce before anthesis in high population density crops. This paper evaluates the hypothesis that quantitative and qualitative changes in the light environment associated with a high leaf area index (LAI) trigger leaf senescence in sunflower (Helianthus annuus L.) canopies. Mean leaf duration (LD, time from achievement of maximum leaf area) of leaf 8 was significantly (P < 0.05) reduced from 51 to 19 days as crop population density was increased from 0.47 to 4.76 plants m−2. High compared to low plant population density was associated with earlier reduction in the photosynthetically active radiation (PAR) and red/far-red ratio (R/FR) reaching the target leaf. However the changes in R/FR preceded those in PAR. When the light environment of individual leaves of isolated plants growing under field conditions was manipulated using filters and FR-reflecting mirrors, LD was positively and linearly related with the mean daily PAR (MDR) received in the FR- (no FR enrichment) treatments. FR enrichment of light reaching the abaxial surface of the leaf significantly (P < 0.05) reduced LD by 9 days at intermediate PAR levels with respect to FR-controls, but did not affect LD at the maximum PAR used in these experiments. However, when light reaching both leaf surfaces was enriched with FR, LD (for leaves receiving maximum PAR) was 13 days shorter than that of the FR- control. These results show that basal leaf senescence in sunflower is enhanced both by a decrease in PAR and by a decrease in R/FR. (author)

  8. Light piping driven photosynthesis in the soil: Low-light adapted active photosynthetic apparatus in the under-soil hypocotyl segments of bean (Phaseolus vulgaris).

    Science.gov (United States)

    Kakuszi, Andrea; Sárvári, Éva; Solti, Ádám; Czégény, Gyula; Hideg, Éva; Hunyadi-Gulyás, Éva; Bóka, Károly; Böddi, Béla

    2016-08-01

    Photosynthetic activity was identified in the under-soil hypocotyl part of 14-day-old soil-grown bean plants (Phaseolus vulgaris L. cv. Magnum) cultivated in pots under natural light-dark cycles. Electron microscopic, proteomic and fluorescence kinetic and imaging methods were used to study the photosynthetic apparatus and its activity. Under-soil shoots at 0-2cm soil depth featured chloroplasts with low grana and starch grains and with pigment-protein compositions similar to those of the above-soil green shoot parts. However, the relative amounts of photosystem II (PSII) supercomplexes were higher; in addition a PIP-type aquaporin protein was identified in the under-soil thylakoids. Chlorophyll-a fluorescence induction measurements showed that the above- and under-soil hypocotyl segments had similar photochemical yields at low (10-55μmolphotonsm(-2)s(-1)) light intensities. However, at higher photon flux densities the electron transport rate decreased in the under-soil shoot parts due to inactivation of the PSII reaction centers. These properties show the development of a low-light adapted photosynthetic apparatus driven by light piping of the above-soil shoot. The results of this paper demonstrate that the classic model assigning source and sink functions to above- and under-soil tissues is to be refined, and a low-light adapted photosynthetic apparatus in under-soil bean hypocotyls is capable of contributing to its own carbon supply. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Effect of Temperature and light intensity on growth and Photosynthetic Activity of Chlamydomonas reinhard II; Efecto de la temperatura e intensidad luminosa sobre el crecimiento y actividad fotosintetica del alga Chlamydomonas Reinhardt II

    Energy Technology Data Exchange (ETDEWEB)

    Alfonsel Jaen, M.; Fernandez Gonzalez, J.

    1985-07-01

    The effect of five temperatures (15,20,25,30 and 35 degree centigree) and two levels of illumination on growth and photosynthetic activity of Chlamydomonas reinhard II has been studied. The growth of the cultures was evaluated by optical density. Photosynthetic activity has been carried out studying either the assimilation rate of C0{sub 2} labelled with C-14 or the oxygen evolution by means of polarographic measurements. The maximum photosynthetic rate has been obtained at 25 degree centigree for the lower level of illumination (2400 lux) and at 35 degree centigree for the higher one (13200 lux) and at 35 degree centigree for the higher ono (13200 lux). These results suggest an interaction of temperature and illumination on photosynthetic activity. (Author) 37 refs.

  10. Patient safety incidents are common in primary care: A national prospective active incident reporting survey.

    Directory of Open Access Journals (Sweden)

    Philippe Michel

    Full Text Available The study objectives were to describe the incidence and the nature of patient safety incidents (PSIs in primary care general practice settings, and to explore the association between these incidents and practice or organizational characteristics.GPs, randomly selected from a national influenza surveillance network (n = 800 across France, prospectively reported any incidents observed each day over a one-week period between May and July 2013. An incident was an event or circumstance that could have resulted, or did result, in harm to a patient, which the GP would not wish to recur. Primary outcome was the incidence of PSIs which was determined by counting reports per total number of patient encounters. Reports were categorized using existing taxonomies. The association with practice and organizational characteristics was calculated using a negative binomial regression model.127 GPs (participation rate 79% reported 317 incidents of which 270 were deemed to be a posteriori judged preventable, among 12,348 encounters. 77% had no consequences for the patient. The incidence of reported PSIs was 26 per 1000 patient encounters per week (95% CI [23‰ -28‰]. Incidents were three times more frequently related to the organization of healthcare than to knowledge and skills of health professionals, and especially to the workflow in the GPs' offices and to the communication between providers and with patients. Among GP characteristics, three were related with an increased incidence in the final multivariable model: length of consultation higher than 15 minutes, method of receiving radiological results (by fax compared to paper or email, and being in a multidisciplinary clinic compared with sole practitioners.Patient safety incidents (PSIs occurred in mean once every two days in the sampled GPs and 2% of them were associated with a definite possibility for harm. Studying the association between organizational features of general practices and PSIs remains a

  11. Photosynthetic Pigments in Diatoms

    Directory of Open Access Journals (Sweden)

    Paulina Kuczynska

    2015-09-01

    Full Text Available Photosynthetic pigments are bioactive compounds of great importance for the food, cosmetic, and pharmaceutical industries. They are not only responsible for capturing solar energy to carry out photosynthesis, but also play a role in photoprotective processes and display antioxidant activity, all of which contribute to effective biomass and oxygen production. Diatoms are organisms of a distinct pigment composition, substantially different from that present in plants. Apart from light-harvesting pigments such as chlorophyll a, chlorophyll c, and fucoxanthin, there is a group of photoprotective carotenoids which includes β-carotene and the xanthophylls, diatoxanthin, diadinoxanthin, violaxanthin, antheraxanthin, and zeaxanthin, which are engaged in the xanthophyll cycle. Additionally, some intermediate products of biosynthetic pathways have been identified in diatoms as well as unusual pigments, e.g., marennine. Marine algae have become widely recognized as a source of unique bioactive compounds for potential industrial, pharmaceutical, and medical applications. In this review, we summarize current knowledge on diatom photosynthetic pigments complemented by some new insights regarding their physico-chemical properties, biological role, and biosynthetic pathways, as well as the regulation of pigment level in the cell, methods of purification, and significance in industries.

  12. Photosynthetic Pigments in Diatoms

    Science.gov (United States)

    Kuczynska, Paulina; Jemiola-Rzeminska, Malgorzata; Strzalka, Kazimierz

    2015-01-01

    Photosynthetic pigments are bioactive compounds of great importance for the food, cosmetic, and pharmaceutical industries. They are not only responsible for capturing solar energy to carry out photosynthesis, but also play a role in photoprotective processes and display antioxidant activity, all of which contribute to effective biomass and oxygen production. Diatoms are organisms of a distinct pigment composition, substantially different from that present in plants. Apart from light-harvesting pigments such as chlorophyll a, chlorophyll c, and fucoxanthin, there is a group of photoprotective carotenoids which includes β-carotene and the xanthophylls, diatoxanthin, diadinoxanthin, violaxanthin, antheraxanthin, and zeaxanthin, which are engaged in the xanthophyll cycle. Additionally, some intermediate products of biosynthetic pathways have been identified in diatoms as well as unusual pigments, e.g., marennine. Marine algae have become widely recognized as a source of unique bioactive compounds for potential industrial, pharmaceutical, and medical applications. In this review, we summarize current knowledge on diatom photosynthetic pigments complemented by some new insights regarding their physico-chemical properties, biological role, and biosynthetic pathways, as well as the regulation of pigment level in the cell, methods of purification, and significance in industries. PMID:26389924

  13. Photosynthetic Pigments in Diatoms.

    Science.gov (United States)

    Kuczynska, Paulina; Jemiola-Rzeminska, Malgorzata; Strzalka, Kazimierz

    2015-09-16

    Photosynthetic pigments are bioactive compounds of great importance for the food, cosmetic, and pharmaceutical industries. They are not only responsible for capturing solar energy to carry out photosynthesis, but also play a role in photoprotective processes and display antioxidant activity, all of which contribute to effective biomass and oxygen production. Diatoms are organisms of a distinct pigment composition, substantially different from that present in plants. Apart from light-harvesting pigments such as chlorophyll a, chlorophyll c, and fucoxanthin, there is a group of photoprotective carotenoids which includes β-carotene and the xanthophylls, diatoxanthin, diadinoxanthin, violaxanthin, antheraxanthin, and zeaxanthin, which are engaged in the xanthophyll cycle. Additionally, some intermediate products of biosynthetic pathways have been identified in diatoms as well as unusual pigments, e.g., marennine. Marine algae have become widely recognized as a source of unique bioactive compounds for potential industrial, pharmaceutical, and medical applications. In this review, we summarize current knowledge on diatom photosynthetic pigments complemented by some new insights regarding their physico-chemical properties, biological role, and biosynthetic pathways, as well as the regulation of pigment level in the cell, methods of purification, and significance in industries.

  14. Spatial analysis of crime incidence and adolescent physical activity.

    Science.gov (United States)

    Robinson, Alyssa I; Carnes, Fei; Oreskovic, Nicolas M

    2016-04-01

    Adolescents do not achieve recommended levels of physical activity. Crime is believed to be a barrier to physical activity among youth, but findings are inconsistent. This study compares the spatial distribution of crime incidences and moderate-to-vigorous physical activity (MVPA) among adolescents in Massachusetts between 2011 and 2012, and examines the correlation between crime and MVPA. Eighty adolescents provided objective physical activity (accelerometer) and location (Global Positioning Systems) data. Crime report data were obtained from the city police department. Data were mapped using geographic information systems, and crime and MVPA densities were calculated using kernel density estimations. Spearman's correlation tested for associations between crime and MVPA. Overall, 1694 reported crimes and 16,702min of MVPA were included in analyses. A strong positive correlation was present between crime and adolescent MVPA (ρ=0.72, pCrime remained positively associated with MVPA in locations falling within the lowest quartile (ρ=0.43, pcrime density. This study found a strong positive association between crime and adolescent MVPA, despite research suggesting the opposite relationship. This counterintuitive finding may be explained by the logic of a common destination: neighborhood spaces which are desirable destinations and promote physical activity may likewise attract crime. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Influence of photosynthetically active radiation and spectral quality on UV-B-induced polyamine accumulation in soybean

    International Nuclear Information System (INIS)

    Kramer, G.F.; Krizek, D.T.; Mirecki, R.M.

    1992-01-01

    UV-B-sensitive (Essex) and -insensitive (Williams) cultivars of soybean (Glycine max) were grown in growth chambers at photosynthetically active radiation (PAR) levels of 300 or 600 μmol m −2 sec −1 provided by either red- and far-red-deficient (MH) or blue-deficient (HPS/DX) lamps or a combination of both. The combined treatment provided a balanced output, similar to that provided by fluorescent plus incandescent lighting across the visible spectrum. Under the combined lamps, plants were exposed to 12 kJ m −2 day −1 of biologically effective UV-B (UV-B BE ) with 6-hr irradiance periods centred midway through the photoperiod. This irradiance corresponded to a decrease in stratospheric ozone of ca 20% for clear sky conditions at Beltsville, MD on 21 June. Plant growth was significantly inhibited by UV-B at 300 but not at 600 μmol m −2 sec −1 PAR. No cultivar differences were noted in the UV-B-induced inhibition of growth, although visible injury was less in Williams than in Essex. PAR had a large effect on polyamine levels in leaves, with higher levels of putrescine (Put) and spermidine observed at 600 than at 300 μmol m −2 sec −1 in both cultivars. UV-B-induced polyamine accumulation was observed primarily in Williams. Under MH or HPS/DX lamps alone, plants were exposed to two different UV-B levels, 9.9 and 12 kJ m −2 day −1 , corresponding to stratospheric ozone reductions of ca 9 and 20%. UV-B inhibited growth at both 300 and 600 μmol m −2 sec −1 PAR under either radiation source. There was no effect of PAR on the UV-B-induced growth inhibition with the HPS/DX lamps, but a partial amelioration of this inhibition occurred in Williams at 600 μmol m −2 sec −1 PAR under MH lamps. Dose-dependent UV-B-induced polyamine accumulation was also observed in both cultivars. PAR increased Put levels under MH but not HPS/DX lamps. These results indicate that the inhibition of UV-B stress by high PAR may require a balance of red and blue

  16. Uptake of diuron and concomitant loss of photosynthetic activity in leaves as visualized by imaging the red chlorophyll fluorescence.

    Science.gov (United States)

    Lichtenthaler, Hartmut K; Langsdorf, Gabriele; Buschmann, Claus

    2013-10-01

    The principles of the chlorophyll (Chl) fluorescence induction kinetics (known as Kautsky effect) and their change by the photosystem II herbicide diuron are presented together with the Chl fluorescence emission spectra of a normal and diuron-inhibited leaf. By imaging the Chl fluorescence emission of green leaves the successive uptake of diuron and the concomitant loss of photosynthetic quantum conversion from the leaf base to the leaf tip are documented.

  17. Exogenous proline mediates alleviation of cadmium stress by promoting photosynthetic activity, water status and antioxidative enzymes activities of young date palm (Phoenix dactylifera L.).

    Science.gov (United States)

    Zouari, M; Ben Ahmed, Ch; Zorrig, W; Elloumi, N; Rabhi, M; Delmail, D; Ben Rouina, B; Labrousse, P; Ben Abdallah, F

    2016-06-01

    The ability of exogenous compatible solutes, such as proline, to counteract cadmium (Cd) inhibitory effects in young date palm plants (Phoenix dactylifera L. cv Deglet Nour) was investigated. Two-year-old date palm plants were subjected for five months at different Cd stress levels (0, 10 and 30 mg CdCl2 kg(-1) soil) whether supplied or not with exogenous proline (20mM) added through the irrigation water. Different levels of Cd stress altered plant growth, gas exchanges and chlorophyll content as well as water status, but at different extent among them. In contrast, an increase of antioxidant enzymes activities of Cd-treated plants in association with high amounts of proline content, hydrogen peroxide (H2O2), thiobarbituric acid reactive substances (TBARS) and electrolyte leakage (EL) were observed. Interestingly, exogenous proline mitigated the adverse effects of Cd on young date palm. Indeed, it alleviated the oxidative damage induced by Cd accumulation and established better levels of plant growth, water status and photosynthetic activity. Moreover, proline-treated plants showed high antioxidant enzymes activities (superoxide dismutase, catalase and glutathione peroxydase) in roots and leaves as compared to Cd-treated plants. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Changes in vigorous physical activity and incident diabetes inmale runners

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Paul T.

    2007-04-30

    We examined the dose-response relationship between changes in reported vigorous exercise (running distance, {Delta}km/wk) and self-reported physician diagnosed diabetes in 25,988 men followed prospectively for (mean {+-} SD) 7.8 {+-} 1.8 years. Logistic regression analyses showed that the log odds for diabetes declined significantly in relation to men's {Delta}km/wk (coefficient {+-} SE: -0.012 {+-} 0.004, P < 0.01), which remained significant when adjusted for BMI (-0.018 {+-} 0.003, P < 0.0001). The decline in the log odds for diabetes was related to the distance run at the end of follow-up when adjusted for baseline distance, with (-0.024 {+-} 0.005, P < 0.0001) or without (-0.027 {+-} 0.005, P < 0.0001) adjustment for BMI. Baseline distance was unrelated to diabetes incidence when adjusted for the distance at the end of follow-up. Compared to men who ran <8 km/wk at the end of follow-up, incidence rates in those who ran {ge} 8 km/wk were 95% lower between 35-44 yrs old (P < 0.0001), 92% lower between 45-54 yrs old (P < 0.0001), 87% lower between 55 and 64 years old (P < 0.0001), and 46% lower between 65-75 yrs old (P = 0.30). For the subset of 6,208 men who maintained the same running distance during follow-up ({+-}5 km/wk), the log odds for diabetes declined with weekly distance run (-0.024 {+-} 0.010, P = 0.02) but not when adjusted for BMI (-0.005 {+-} 0.010, P = 0.65). Conclusion: Vigorous exercise significantly reduces diabetes incidence, due in part to the prevention of age-related weight gain and in part to other exercise effects. Physical activity decreases the risk of type 2 diabetes [1-10]. Moderate and vigorous exercise are purported to produce comparable reductions in diabetes risk if the energy expenditure is the same [3,10]. The optimal physical activity dose remains unclear, however, with some [4-7] but not all studies [1,8,9] showing continued reduction in diabetes for high versus intermediate energy expenditures. The National Runners

  19. Fluoranthene induced changes in photosynthetic pigments, biochemical compounds and enzymatic activities in two microalgal species: Chlorella vulgaris Beijerinck and Desmodesmus subspicatus Chodat

    Directory of Open Access Journals (Sweden)

    Miral Patel

    2014-02-01

    Full Text Available The photosynthetic pigments, biochemical and enzymatic activities in two freshwater microalgal species, Chlorella vulgaris and Desmodesmus subspicatus at different fluoranthene concentrations were compared with the control conditions. During 16-days of incubation period when treated with fluoranthene, both microalgal species exhibited variable amount of photosynthetic pigment, biochemical compounds and enzymatic activities. The addition of fluoranthene at concentrations ranged from 1.5 mg l-1; to 10 mg l-1; to microalgal cultures led to changes in all different metabolites but the patterns varied from species to species. Among the two species tested, pigment, biochemical and enzymatic contents were remarkably declined from 7 % to 95% in C. vulgaris. Moreover, all metabolites in D. subspicatus also diminishing significantly by 3% to 88% of fluoranthene doses (10ppm. These results suggest that fluoranthene-induced changes of pigments, biochemical and enzymatic variations in test microalgae, D. subspicatus and C. vulgaris, might reveal its resistance and ability to metabolize PAHs. At the same time, the PAH impact changes on different metabolic activities were higher at 12 and 16 days than at 4 and 8 days in treated microalgae. DOI: http://dx.doi.org/10.3126/ije.v3i1.9941 International Journal of Environment Vol.3(1 2014: 41-55

  20. Photosynthetic water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Greenbaum, E.

    1981-01-01

    The photosynthetic unit of hydrogen evolution, the turnover time of photosynthetic hydrogen production, and hydrogenic photosynthesis are discussed in the section on previous work. Recent results are given on simultaneous photoproduction of hydrogen and oxygen, kinetic studies, microscopic marine algae-seaweeds, and oxygen profiles.

  1. Responses of epidermal cell turgor pressure and photosynthetic activity of leaves of the atmospheric epiphyte Tillandsia usneoides (Bromeliaceae) after exposure to high humidity.

    Science.gov (United States)

    Martin, Craig E; Rux, Guido; Herppich, Werner B

    2013-01-01

    It has been well-established that many epiphytic bromeliads of the atmospheric-type morphology, i.e., with leaf surfaces completely covered by large, overlapping, multicellular trichomes, are capable of absorbing water vapor from the atmosphere when air humidity increases. It is much less clear, however, whether this absorption of water vapor can hydrate the living cells of the leaves and, as a consequence, enhance physiological processes in such cells. The goal of this research was to determine if the absorption of atmospheric water vapor by the atmospheric epiphyte Tillandsia usneoides results in an increase in turgor pressure in leaf epidermal cells that subtend the large trichomes, and, by using chlorophyll fluorescence techniques, to determine if the absorption of atmospheric water vapor by leaves of this epiphyte results in increased photosynthetic activity. Results of measurements on living cells of attached leaves of this epiphytic bromeliad, using a pressure probe and of whole-shoot fluorescence imaging analyses clearly illustrated that the turgor pressure of leaf epidermal cells did not increase, and the photosynthetic activity of leaves did not increase, following exposure of the leaves to high humidity air. These results experimentally demonstrate, for the first time, that the absorption of water vapor following increases in atmospheric humidity in atmospheric epiphytic bromeliads is mostly likely a physical phenomenon resulting from hydration of non-living leaf structures, e.g., trichomes, and has no physiological significance for the plant's living tissues. Copyright © 2012 Elsevier GmbH. All rights reserved.

  2. Effect of the temperature, pH and irradiance on the photosynthetic activity by Scenedesmus obtusiusculus under nitrogen replete and deplete conditions.

    Science.gov (United States)

    Cabello, Juan; Toledo-Cervantes, Alma; Sánchez, León; Revah, Sergio; Morales, Marcia

    2015-04-01

    This paper evaluates the effect of the irradiance, pH and temperature on the photosynthetic activity (PA) of Scenedesmus obtusiusculus under N-replete and N-deplete conditions through oxygen measurements. The highest PA values were 160 mgO2 gb(-1) h(-1) at 620 μmol m(-2) s(-1), 35 °C and pH of 8 under N-replete conditions and 3.3 mgO2 gb(-1) h(-1) at 100 μmol m(-2) s(-1), 28.5 °C and pH of 5.5 for N-deplete conditions. Those operation conditions were tested in a flat-panel photobioreactor. The biomass productivity was 0.97 gb L(-1) d(-1) under N-replete conditions with a photosynthetic efficiency (PE) of 4.4% yielding 0.85 gb mol photon(-1). Similar biomass productivity was obtained under N-deplete condition; and the lipid productivity was 0.34 gL L(-1) d(-1) with a PE of 7.8% yielding 0.39 gL mol photon(-1). The apparent activation and deactivation energies were 16.1 and 30 kcal mol(-1), and 11.9 and 15.3 kcal mol(-1), for N-replete and N-deplete conditions, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Incidence and Duration of Breastfeedings in Active Duty Military Women

    Science.gov (United States)

    1998-05-21

    breastfeeding has been examined in health maintenance organizations (Samuels, Margen, Schoen 1985), in low socioeconomic classes ( Rassin ... Rassin , Richardson, Baranowski, Nader, Guenther, Bee, and Brown (1984) evaluated the incidence of breast-feeding in low socioeconomic mothers in...14) 527-37. Rassin , D.K., Richardson, C.J., Baranowski, T., Nader, P.R., Guenther, N., Bee, D.E. & Brown, J.P. (1984). Incidence of breast-feeding

  4. Proline over-accumulation alleviates salt stress and protects photosynthetic and antioxidant enzyme activities in transgenic sorghum [Sorghum bicolor (L.) Moench].

    Science.gov (United States)

    Surender Reddy, P; Jogeswar, Gadi; Rasineni, Girish K; Maheswari, M; Reddy, Attipalli R; Varshney, Rajeev K; Kavi Kishor, P B

    2015-09-01

    Shoot-tip derived callus cultures of Sorghum bicolor were transformed by Agrobacterium tumefaciens as well as by bombardment methods with the mutated pyrroline-5-carboxylate synthetase (P5CSF129A) gene encoding the key enzyme for proline biosynthesis from glutamate. The transgenics were selfed for three generations and T4 plants were examined for 100 mM NaCl stress tolerance in pot conditions. The effect of salt stress on chlorophyll and carotenoid contents, photosynthetic rate, stomatal conductance, internal carbon dioxide concentration, transpiration rates, intrinsic transpiration and water use efficiencies, proline content, MDA levels, and antioxidant enzyme activities were evaluated in 40-day-old transgenic lines and the results were compared with untransformed control plants. The results show that chlorophyll content declines by 65% in untransformed controls compared to 30-38% loss (significant at P activity) was reduced in untransformed controls almost completely, while it declined by 62-88% in different transgenic lines. Salinity induced ca 100% stomatal closure in untransformed plants, while stomatal conductance was decreased only by 64-81% in transgenics after 4 days. The intercellular CO2 decreased by ca 30% in individual transgenic lines. Malondialdehyde (MDA) content was lower in transgenics compared to untransformed controls. The activities of superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6) and glutathione reductase (GR; EC1.8.1.7) were quantified in leaves exposed to 100 mM NaCl stress and found higher in transgenics. The results suggest that transgenic lines were able to cope better with salt stress than untransformed controls by protecting photosynthetic and antioxidant enzyme activities. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  5. Photosynthetic fuel for heterologous enzymes

    DEFF Research Database (Denmark)

    Mellor, Silas Busck; Vavitsas, Konstantinos; Nielsen, Agnieszka Janina Zygadlo

    2017-01-01

    Plants, cyanobacteria, and algae generate a surplus of redox power through photosynthesis, which makes them attractive for biotechnological exploitations. While central metabolism consumes most of the energy, pathways introduced through metabolic engineering can also tap into this source of reduc......Plants, cyanobacteria, and algae generate a surplus of redox power through photosynthesis, which makes them attractive for biotechnological exploitations. While central metabolism consumes most of the energy, pathways introduced through metabolic engineering can also tap into this source...... on electrostatically steered complex formation, they form productive electron transfer complexes with non-native enzymes. A handful of examples demonstrate channeling of photosynthetic electrons to drive the activity of heterologous enzymes, and these focus mainly on hydrogenases and cytochrome P450s. However......, competition from native pathways and inefficient electron transfer rates present major obstacles, which limit the productivity of heterologous reactions coupled to photosynthesis. We discuss specific approaches to address these bottlenecks and ensure high productivity of such enzymes in a photosynthetic...

  6. A framework for consistent estimation of leaf area index, fraction of absorbed photosynthetically active radiation, and surface albedo from MODIS time-series data

    DEFF Research Database (Denmark)

    Xiao, Zhiqiang; Liang, Shunlin; Wang, Jindi

    2015-01-01

    model and the MODIS surface reflectance data. The estimated LAI values were then input into the ACRM to calculate the surface albedo and the fraction of absorbed photosynthetically active radiation (FAPAR). For snow-covered areas, the surface albedo was calculated as the underlying vegetation canopy...... albedo plus the weighted distance between the underlying vegetation canopy albedo and the albedo over deep snow. The LAI/FAPAR and surface albedo values estimated using this framework were compared with MODIS collection 5 eight-day 1-km LAI/FAPAR products (MOD15A2) and 500-m surface albedo product (MCD43......-series MODerate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data. If the reflectance data showed snow-free areas, an ensemble Kalman filter (EnKF) technique was used to estimate leaf area index (LAI) for a two-layer canopy reflectance model (ACRM) by combining predictions from a phenology...

  7. Effects of irradiance and prey deprivation on growth, cell carbon and photosynthetic activity of the freshwater kleptoplastidic dinoflagellate Nusuttodinium (= Gymnodinium) aeruginosum (Dinophyceae)

    DEFF Research Database (Denmark)

    Drumm, Kirstine; Liebst-Olsen, Mette; Daugbjerg, Niels

    2017-01-01

    not explain the observed growth rates at high irradiances. Cultures of N. aeruginosum subjected to prey starvation were able to survive for at least 27 days in the light. The sequestered chloroplasts maintained their photosynthetic activity during the entire period of starvation, during which the population......The freshwater dinoflagellate Nusuttodinium aeruginosum lacks permanent chloroplasts. Rather it sequesters chloroplasts as well as other cell organelles, like mitochondria and nuclei, from ingested cryptophyte prey. In the present study, growth rates, cell production and photosynthesis were...... measured at seven irradiances, ranging from 10 to 140 µmol photons m-2s-1, when fed the cryptophyte Chroomonas sp. Growth rates were positively influenced by irradiance and increased from 0.025 d-1 at 10 µmol photons m-2s-1 to maximum growth rates of ~0.3 d-1 at irradiances ≥ 40 µmol photons m-2s-1...

  8. Vitamin K dependent protein activity and incident ischemic cardiovascular disease: The multi ethnic study of atherosclerosis

    Science.gov (United States)

    OBJECTIVE: Vitamin K-dependent proteins (VKDPs), which require post-translational modification to achieve biological activity, seem to contribute to thrombus formation, vascular calcification, and vessel stiffness. Whether VKDP activity is prospectively associated with incident cardiovascular diseas...

  9. Recent advances in studies on photosynthetic microorganisms and photobioreactors. ; Production of physiologically active substance (5-aminolevulinic acid) using photosynthetic bacteria. Hikari gosei biseibutsu no kino kaihatsu to foto baioriakuta. ; Hikari gosei saikin ni yoru seiri kassei busshitsu (5-aminoreburin san) no seisan

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, K. (The Hiroshima-Denki Inst. of Technology, Hiroshima (Japan)); Tanaka, T.; Hotta, K. (Cosmo Research Inst. Inc., Tokyo (Japan)); Nishio, N.; Nagai, S. (Hiroshima Univ. (Japan). Faculty of Engineering)

    1993-11-25

    Among photosynthetic bacteria, purple non-sulfurous bacteria can be multiplicated under anaerobic bright and aerobic dark conditions, and the speed of multiplication is relatively high. These bacteria contain much proteins, vitamins and dyes, and are useful as SCPs. The authors have found a phenomenon that Rhodobacter sphaeroides, a species of purple non-sulfur bacteria, egests 5-aminolevulinic acid (ALA) when levulinic acid (LA), a tetrapyrrole biosynthesis inhibitor, is added to the culture medium, ALAs are known as tetrapyrrole compounds such as chlorophyll and vitamin B12. ALA has various physiological activities against plants, but has not been mass-produced because its chemical synthesis is not easy. In this article, production of ALA using photosynthetic R. sphaeroides, which is said to have a relatively high ARA synthesis activity, is described. 14 refs., 4 figs.

  10. Evaluation of fraction of absorbed photosynthetically active radiation products for different canopy radiation transfer regimes: methodology and results using Joint Research Center products derived from SeaWiFS against ground-based estimations.

    Science.gov (United States)

    Nadine Gobron; Bernard Pinty; Ophélie Aussedat; Jing M. Chen; Warren B. Cohen; Rasmus Fensholt; Valery Gond; Karl Fred Huemmrich; Thomas Lavergne; Frédéric Méline; Jeffrey L. Privette; Inge Sandholt; Malcolm Taberner; David P. Turner; Michael M. Verstraete; Jean-Luc Widlowski

    2006-01-01

    This paper discusses the quality and the accuracy of the Joint Research Center (JRC) fraction of absorbed photosynthetically active radiation (FAPAR) products generated from an analysis of Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data. The FAPAR value acts as an indicator of the presence and state of the vegetation and it can be estimated from remote sensing...

  11. The changing incidence of AIDS events in patients receiving highly active antiretroviral therapy

    NARCIS (Netherlands)

    D'Arminio Monforte, Antonella; Sabin, Caroline A.; Phillips, Andrew; Sterne, Jonathan; May, Margaret; Justice, Amy; Dabis, Francois; Grabar, Sophie; Ledergerber, Bruno; Gill, John; Reiss, Peter; Egger, Matthias

    2005-01-01

    BACKGROUND: Although the incidence of most AIDS events declines after initiation of highly active antiretroviral therapy (HAART), this decline is more rapid for some conditions than others. We herein describe the decline in incidence of AIDS-defining events among 12,574 antiretroviral-naive

  12. Incidence of discontinuation of highly active antiretroviral combination therapy (HAART) and its determinants

    NARCIS (Netherlands)

    van Roon, E N; Verzijl, J M; Juttmann, J R; Lenderink, A W; Blans, M J; Egberts, A C

    1999-01-01

    OBJECTIVE: To determine the incidence and determinants for discontinuation of initial highly active antiretroviral therapy (HAART). DESIGN: In this retrospective follow-up study from hospital files and pharmacy dispensing data, a standard dataset was collected including patient characteristics,

  13. Effect of planting density on fruit size, light-interception and photosynthetic activity of vertically trained watermelon (Citrullus lanatus (Thunb.) Matsum. et Nakai) plants

    International Nuclear Information System (INIS)

    Watanabe, S.; Nakano, Y.; Okano, K.

    2003-01-01

    Summary The effect of planting density on fruit size of vertically trained watermelon (Citrullus lanatus (Thunb.) Matsum. et Nakai) plants was investigated with regard to light - interception characteristics and photosynthetic production. Watermelon plants, grafted on bottle gourd, were grown in a glasshouse at different planting densities. Two vines per plant were allowed to grow and trained vertically. One hand-pollinated fruit per plant was set around the 15th node on either vine. The solar radiation and photosynthetic rate of individual leaves during fruit development period were determined by an integrated solarimeter film and a portable photosynthesis system, respectively. Fruit size was significantly decreased as the planting density increased, whereas soluble solids content of the fruits was affected little. The solar radiation and the photosynthetic rate of the individual leaves gradually decreased as the leaf position became lower at all planting densities on account of shading; those at lower leaves tended to decrease as the planting density increased. Fruit size was closely related to both the total solar radiation and the photosynthetic production per plant. In conclusion, the difference in fruit size among the planting densities is attributed to the photosynthetic productivity of the whole plant, which is mainly a function of the total solar radiation. This paper appears to be the first trial relating the influence of light interception and photosynthetic rates in high density plantings of vertically trained watermelon plants on fruit size

  14. Activity Regulates the Incidence of Heteronymous Sensory-Motor Connections

    Science.gov (United States)

    Mendelsohn, Alana I.; Simon, Christian M.; Abbott, L. F.; Mentis, George Z.; Jessell, Thomas M.

    2015-01-01

    Summary The construction of spinal sensory-motor circuits involves the selection of appropriate synaptic partners and the allocation of precise synaptic input densities. Many aspects of spinal sensory-motor selectivity appear to be preserved when peripheral sensory activation is blocked, which has led to a view that sensory-motor circuits are assembled in an activity-independent manner. Yet it remains unclear whether activity-dependent refinement has a role in the establishment of connections between sensory afferents and those motor pools that have synergistic biomechanical functions. We show here that genetically abolishing central sensory-motor neurotransmission leads to a selective enhancement in the number and density of such “heteronymous” connections, whereas other aspects of sensory-motor connectivity are preserved. Spike-timing dependent synaptic refinement represents one possible mechanism for the changes in connectivity observed after activity blockade. Our findings therefore reveal that sensory activity does have a limited and selective role in the establishment of patterned monosynaptic sensory-motor connections. PMID:26094608

  15. Effects of irradiance and prey deprivation on growth, cell carbon and photosynthetic activity of the freshwater kleptoplastidic dinoflagellate Nusuttodinium (= Gymnodinium aeruginosum (Dinophyceae.

    Directory of Open Access Journals (Sweden)

    Kirstine Drumm

    Full Text Available The freshwater dinoflagellate Nusuttodinium aeruginosum lacks permanent chloroplasts. Rather it sequesters chloroplasts as well as other cell organelles, like mitochondria and nuclei, from ingested cryptophyte prey. In the present study, growth rates, cell production and photosynthesis were measured at seven irradiances, ranging from 10 to 140 μmol photons m-2s-1, when fed the cryptophyte Chroomonas sp. Growth rates were positively influenced by irradiance and increased from 0.025 d-1 at 10 μmol photons m-2s-1 to maximum growth rates of ~0.3 d-1 at irradiances ≥ 40 μmol photons m-2s-1. Similarly, photosynthesis ranged from 1.84 to 36.9 pg C cell-1 h-1 at 10 and 140 μmol photons m-2s-1, respectively. The highest rates of photosynthesis in N. aeruginosum only corresponded to ~25% of its own cell carbon content and estimated biomass production. The measured rates of photosynthesis could not explain the observed growth rates at high irradiances. Cultures of N. aeruginosum subjected to prey starvation were able to survive for at least 27 days in the light. The sequestered chloroplasts maintained their photosynthetic activity during the entire period of starvation, during which the population underwent 4 cell divisions. This indicates that N. aeruginosum has some control of the chloroplasts, which may be able to replicate. In conclusion, N. aeruginosum seems to be in an early stage of chloroplast acquisition with some control of its ingested chloroplasts.

  16. Effects of irradiance and prey deprivation on growth, cell carbon and photosynthetic activity of the freshwater kleptoplastidic dinoflagellate Nusuttodinium (= Gymnodinium) aeruginosum (Dinophyceae).

    Science.gov (United States)

    Drumm, Kirstine; Liebst-Olsen, Mette; Daugbjerg, Niels; Moestrup, Øjvind; Hansen, Per Juel

    2017-01-01

    The freshwater dinoflagellate Nusuttodinium aeruginosum lacks permanent chloroplasts. Rather it sequesters chloroplasts as well as other cell organelles, like mitochondria and nuclei, from ingested cryptophyte prey. In the present study, growth rates, cell production and photosynthesis were measured at seven irradiances, ranging from 10 to 140 μmol photons m-2s-1, when fed the cryptophyte Chroomonas sp. Growth rates were positively influenced by irradiance and increased from 0.025 d-1 at 10 μmol photons m-2s-1 to maximum growth rates of ~0.3 d-1 at irradiances ≥ 40 μmol photons m-2s-1. Similarly, photosynthesis ranged from 1.84 to 36.9 pg C cell-1 h-1 at 10 and 140 μmol photons m-2s-1, respectively. The highest rates of photosynthesis in N. aeruginosum only corresponded to ~25% of its own cell carbon content and estimated biomass production. The measured rates of photosynthesis could not explain the observed growth rates at high irradiances. Cultures of N. aeruginosum subjected to prey starvation were able to survive for at least 27 days in the light. The sequestered chloroplasts maintained their photosynthetic activity during the entire period of starvation, during which the population underwent 4 cell divisions. This indicates that N. aeruginosum has some control of the chloroplasts, which may be able to replicate. In conclusion, N. aeruginosum seems to be in an early stage of chloroplast acquisition with some control of its ingested chloroplasts.

  17. Radiative transfer in shrub savanna sites in Niger: preliminary results from HAPEX-Sahel. 2. Photosynthetically active radiation interception of the woody layer

    International Nuclear Information System (INIS)

    Bégué, A.; Hanan, N.P.; Prince, S.D.

    1994-01-01

    Interception by the woody layer of photosynthetically active radiation (PAR) was measured and calculated for two Guiera senegalensis J.F. Gmel, shrub savannas in Ouallam, Western Niger, in 1991 as part of the HAPEX-Sahel experiment. Two different scales were considered. At the plant scale, PAR interception was measured throughout the day with amorphous silicon sensors, together with detailed measurements of the structure of the shrubs (size of the ‘envelope’ of the shrub, area index, and angular distribution of the leaves and the branches). These data permitted us to develop and validate a simple radiative transfer model in which the shrubs are represented by porous cylinders; the total transmissivity (or porosity) of the shrubs estimated by the model was approximately 0.4. It indicates that semi-arid shrubs cannot be considered opaque objects and that the fraction of ground covered with plants is a poor indicator of the PAR interception efficiency of the canopy. The model was also applied at a landscape scale to calculate the daily PAR interception of two shrub savanna sites. This value is needed to model primary production in conjunction with remotely sensed and production data acquired simultaneously on the sites. (author)

  18. Distribución espacial de la radiación fotosintéticamente activa en Argentina Spatial distribution of photosynthetically active radiation (par in Argentina

    Directory of Open Access Journals (Sweden)

    Hugo Grossi Gallegos

    2004-12-01

    Full Text Available Una de las informaciones requeridas a menudo para estudiar el balance energético o el crecimiento de un cultivo particular es la radiación solar. Si bien puede disponerse en general del dato de irradiación global (medida o estimada, no es frecuente contar con valores de radiación fotosintéticamente activa. Teniendo en cuenta la relación determinada entre esta última y la global (0,47, como así también la existencia de cartas que dan la distribución del promedio mensual de la irradiación solar global diaria en Argentina, en este trabajo se presenta un conjunto similar de cartas mensuales de la radiación fotosintéticamente activa.Solar radiation is information often required for studying energy balance or the growth of a specific culture. Although in general it is able to dispose of measured or estimated global irradiation data, information of photosynthetically active radiation (PAR is not always available. Taking into account an empirical relationship established between daily totals of PAR and global solar radiation (0.47, and the existence of charts with the distribution of monthly mean values of daily global irradiation in Argentina, PAR monthly charts are presented in this work.

  19. Modeling the reflection of Photosynthetically active radiation in a monodominant floodable forest in the Pantanal of Mato Grosso State using multivariate statistics and neural networks.

    Science.gov (United States)

    Curado, Leone F A; Musis, Carlo R DE; Cunha, Cristiano R DA; Rodrigues, Thiago R; Pereira, Vinicius M R; Nogueira, José S; Sanches, Luciana

    2016-09-01

    The study of radiation entrance and exit dynamics and energy consumption in a system is important for understanding the environmental processes that rule the biosphere-atmosphere interactions of all ecosystems. This study provides an analysis of the interaction of energy in the form of photosynthetically active radiation (PAR) in the Pantanal, a Brazilian wetland forest, by studying the variation of PAR reflectance and its interaction with local rainfall. The study site is located in Private Reserve of Natural Heritage, Mato Grosso State, Brazil, where the vegetation is a monodominant forest of Vochysia divergens Phol. The results showed a high correlation between the reflection of visible radiation and rainfall; however, the behavior was not the same at the three heights studied. An analysis of the hourly variation of the reflected waves also showed the seasonality of these phenomena in relation to the dry and rainy seasons. A predictive model for PAR was developed with a neural network that has a hidden layer, and it showed a determination coefficient of 0.938. This model showed that the Julian day and time of measurements had an inverse association with the wind profile and a direct association with the relative humidity profile.

  20. Effects of 1-butanol, neomycin and calcium on the photosynthetic ...

    African Journals Online (AJOL)

    ajl yemi

    2011-10-31

    Oct 31, 2011 ... The results show that,. 0.04% 1-butanol and 0.05 mmol L-1 Ca2+ has a significant effect on the net photosynthetic rate (Pn) of the three tested materials. ... pepc transgenic rice; Pn, net photosynthetic rate; PLD, phospholipase D; PLC ...... Fukayama H, Hatch MD, Tamai T(2003).Activity regulation and.

  1. AM Fungi Influences the Photosynthetic Activity, Growth and Antioxidant Enzymes in Allium sativum L. under Salinity Condition

    Directory of Open Access Journals (Sweden)

    Mahesh BORDE

    2010-12-01

    Full Text Available Potential of Arbuscular mycorrhizal (AM fungi in alleviating adverse salt effects on growth was tested in garlic (Allium sativum L.. Towards this objective we analyzed the AM root colonization and the activities of various antioxidant enzymes like peroxidase, catalase, and superoxide dismutase at 0, 100, 200 and 300 mM salinity levels. The activities of all the antioxidant enzymes studied were found to be increased in AM garlic plants. Antioxidant activity was maximum in 100 and 200 mM NaCl (sodium chloride in AM and non-AM plants. Proline accumulation was induced by salt levels and it was more in leaves as well as roots of AM plants as compared to non-AM plants, this indicating that mycorrhiza reduced salt injury. Growth parameters of garlic plants like leaf area, plant fresh and dry weight and antioxidant enzyme activities were higher at moderate salinity level. This work suggests that the mycorrhiza helps garlic plants to perform better under moderate salinity level by enhancing the antioxidant activity and proline content as compared to non-AM plants.

  2. Photosynthetic Photovoltaic Cells

    Science.gov (United States)

    2007-06-21

    Immobilization of Proteins on a Carbon Electrode Surface - Oriented Immobilization of Photosynthetic Reaction Centers. Journal of Electroanalytical ...NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) B. PERFORMING ORGANIZATION MASSACHUSETTS INSTITUTE OF TECHNOLOGY REPORT...no longer must absorb all the light. Thus, its quantum efficiency can approach 100% potentially doubling the performance of organic solar cells. 15

  3. Effect of cycocel on photosynthetic activity and essential oil of fennel (Foeniculum vulgare Mill. under drought stress

    Directory of Open Access Journals (Sweden)

    Fatemeh Nouri

    2014-12-01

    Full Text Available Drought stress is one of the most important and most common environmental stresses that limit plant growth. Photosynthesis is the main determinant of plant growth and its retention ability under environmental stress condition is important for preservation of growth stability. To study the effect of spraying CCC on photosynthesis activity and essential oil content on 'Foeniculum vulgare', an experiment was done in split plot design based on complete block with four replications in research field of University of Zanjan in 2011. Levels of drought stress included, control, soft stress (when 30% of available water was out of soil, severe stress (when 90% of available water was out of soil, and three concentration of CCC 0, 1500 and 3000 mg/L. The results showed that between rates foliar application on physiologic characteristics as photosynthesis rate, transpiration severity, RWC and TΔ intercellular (Ci, stomata conductivity, mesophyll conductivity and essential oil content was significant. By spraying 3000 mg/L CCC, balanced the plant position against drought stress and could reduce negative effect. Foliar application of CCC caused significant increase in photosynthesis rate, mesophyll conductivity and significant decrease stomata conductivity, transpiration severity under drought stress and could increase essential oil content under soft stress. In this study, foliar application of CCC to content 3000 mg/L had the highest effect on this characters.

  4. Visualization of water usage and photosynthetic activity of street trees exposed to 2 ppm of SO{sub 2}-A combined evaluation by cold neutron and chlorophyll fluorescence imaging

    Energy Technology Data Exchange (ETDEWEB)

    Matsushima, U. [Faculty of Agriculture, Iwate University (Japan)], E-mail: uzuki@iwate-u.ac.jp; Kardjilov, N.; Hilger, A.; Manke, I. [SF3, Helmholtz Center Berlin for Materials and Energy (Germany); Shono, H. [Faculty of Agriculture, Iwate University (Japan); Herppich, W.B. [Department of Horticultural Engineering, Leibniz Institute for Agricultural Engineering Potsdam-Bornim (Germany)

    2009-06-21

    Photosynthetic efficacy and auto-exhaust-fume resistance of street trees were evaluated by cold neutron radiography (CNR) with D{sub 2}O tracer and chlorophyll fluorescence (CF) imaging. With these techniques, information on the responses of water usage and photosynthetic activity of plants exposed to simulate toxic auto-exhaust fumes (2 ppm SO{sub 2} in air) were obtained. Branches of hibiscus trees were detached, placed into a tub with aerated water and used for the experiments after rooting. A CF image was taken before SO{sub 2} was applied for 1 h. During the experiment, CNR and CF imaging were conduced. H{sub 2}O and D{sub 2}O in the plant container were exchanged every 30 min to observe water uptake. D{sub 2}O tracer clearly showed water uptake into the hibiscus stem during each treatment. When the atmosphere was changed from simulated auto-exhaust fumes to normal air again, the amount of D{sub 2}O and, hence, water uptake increased. CF imaging was well suited to evaluate the effects of SO{sub 2} as simulated toxic auto-exhaust fumes on plants. The maximum photochemical efficiency (F{sub v}/F{sub m}), a sensitive indicator of the efficacy and the integrity of plants' photosynthesis, immediately dropped by 30% after supplying the simulated auto-exhaust fumes. This indicates that toxic auto-exhaust fumes negatively affected the photosynthetic activity of hibiscus leaves. Simultaneous CNR and CF imaging successfully visualized variations of photosynthetic activity and water uptake in the sample. Thus, this combination method was effective to non-destructive analyze the physiological status of plants.

  5. Flowering and Growth Responses of Cultivated Lentil and WildLensGermplasm toward the Differences in Red to Far-Red Ratio and Photosynthetically Active Radiation.

    Science.gov (United States)

    Yuan, Hai Y; Saha, Shyamali; Vandenberg, Albert; Bett, Kirstin E

    2017-01-01

    Understanding environmental responses of pulse crop species and their wild relatives will play an important role in developing genetic strategies for crop improvement in response to changes in climate. This study examined how cultivated lentil and wild Lens germplasm responded to different light environments, specifically differences in red/far-red ratio (R/FR) and photosynthetically active radiation (PAR). Three genotypes of each the seven Lens species were grown in environmentally controlled growth chambers equipped to provide light treatments consisting of different R/FR ratios and PAR values. Our results showed that overall, days to flower of Lens genotypes were mainly influenced by the R/FR induced light quality change but not by the PAR related light intensity change. The cultivated lentil ( L. culinaris ) showed consistent, accelerated flowering in response to the low R/FR light environment together with three wild lentil genotypes ( L. orientalis IG 72611, L. tomentosus IG 72830, and L. ervoides IG 72815) while most wild lentil genotypes had reduced responses and flowering time was not significantly affected. The longest shoot length, longest internode length, and largest leaflet area were observed under the low R/FR low PAR environment for both cultivated and wild lentils. The distinctly different responses between flowering time and elongation under low R/FR conditions among wild Lens genotypes suggests discrete pathways controlling flowering and elongation, which are both components of shade avoidance responses. The yield and above-ground biomass of Lens genotypes were the highest under high R/FR high PAR conditions, intermediate under low R/FR low PAR conditions, and lowest under high R/FR low PAR light conditions. Three L. lamottei genotypes (IG 110809, IG 110810, and IG 110813) and one L. ervoides genotype (IG 72646) were less sensitive in their time to flower responses while maintaining similar yield, biomass, and harvest index across all three light

  6. Negativ feedback regulation is responsible for the non-liner modulation of photosynthetic activity in plants and cyanobacteria exposed to a dynamic light environment

    Czech Academy of Sciences Publication Activity Database

    Nedbal, Ladislav

    2003-01-01

    Roč. 1607, č. 1 (2003), s. 5-17 ISSN 0166-8595 Institutional research plan: CEZ:AV0Z6087904; MSM123100001 Keywords : photosynthetic Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.239, year: 2003

  7. Physical Activity and Incident Hypertension in African Americans: The Jackson Heart Study.

    Science.gov (United States)

    Diaz, Keith M; Booth, John N; Seals, Samantha R; Abdalla, Marwah; Dubbert, Patricia M; Sims, Mario; Ladapo, Joseph A; Redmond, Nicole; Muntner, Paul; Shimbo, Daichi

    2017-03-01

    There is limited empirical evidence to support the protective effects of physical activity in the prevention of hypertension among African Americans. The purpose of this study was to examine the association of physical activity with incident hypertension among African Americans. We studied 1311 participants without hypertension at baseline enrolled in the Jackson Heart Study, a community-based study of African Americans residing in Jackson, Mississippi. Overall physical activity, moderate-vigorous physical activity, and domain-specific physical activity (work, active living, household, and sport/exercise) were assessed by self-report during the baseline examination (2000-2004). Incident hypertension, assessed at examination 2 (2005-2008) and examination 3 (2009-2013), was defined as the first visit with systolic/diastolic blood pressure ≥140/90 mm Hg or self-reported antihypertensive medication use. Over a median follow-up of 8.0 years, there were 650 (49.6%) incident hypertension cases. The multivariable-adjusted hazard ratios (95% confidence interval) for incident hypertension comparing participants with intermediate and ideal versus poor levels of moderate-vigorous physical activity were 0.84 (0.67-1.05) and 0.76 (0.58-0.99), respectively ( P trend=0.038). A graded, dose-response association was also present for sport/exercise-related physical activity (Quartiles 2, 3, and 4 versus Quartile 1: 0.92 [0.68-1.25], 0.87 [0.67-1.13], 0.75 [0.58-0.97], respectively; P trend=0.032). There were no statistically significant associations observed for overall physical activity, or work, active living, and household-related physical activities. In conclusion, the results of the current study suggest that regular moderate-vigorous physical activity or sport/exercise-related physical activity may reduce the risk of developing hypertension in African Americans. © 2017 American Heart Association, Inc.

  8. Correlations Between Physical Activity, Smoking Habit And Attitude In Elderly With Incidence of Osteoporosis

    Directory of Open Access Journals (Sweden)

    Kiki Familia Dimyati

    2017-04-01

    Full Text Available Osteoporosis was one of degenerative disease that is common in the elderly. There was a several of risk factors of osteoporosis. Two of them were physical activity and smoking habits. Attitude was one part of a person’s behavior that may affect the prevention of disease. This study aimed to analyze the affect of physical activity, smoking habits, and attitude of the elderly to incidence of osteoporosis. This study is an observational study with case control design. The number of samples in this study was 66 elderly who visited Osteoporosis Clinic Husada Utama Hospital in Surabaya. Respondent selection taken with systematic random sampling. The independent variables of this study were physical activity, smoking habit, and attitude, while the dependent variable was incidence of osteoporosis. Based on correlation analysis with logistic regression test showed there was a significant correlation (p<0,05 between physical activity, smoking habits, and attitude. Odds Ratio (OR in this study for physical activity was 14,764 ,smoking habit was 9,646 and attitude was 5,623. The conclusion of this study, there was physical activity as a dominant affect after controlled smoking habits and attitude to incidence of osteoporosis. The suggestion is to do physical activity three times a week, consume healthy food and beverage, take an enough sleep,reduce stress factors and stop smoking also.   Keywords: Physical activity, smoking habits, elderly

  9. Counting viruses and bacteria in photosynthetic microbial mats

    NARCIS (Netherlands)

    Carreira, C.; Staal, M.; Middelboe, M.; Brussaard, C.P.D.

    2015-01-01

    Viral abundances in benthic environments are the highest found in aquatic systems. Photosynthetic microbial mats represent benthic environments with high microbial activity and possibly high viral densities, yet viral abundances have not been examined in such systems. Existing extraction procedures

  10. Unwanted Sexual Activity among Peers during Early and Middle Adolescence: Incidence and Risk Factors.

    Science.gov (United States)

    Small, Stephen A.; Kerns, Donell

    1993-01-01

    Assessed incidence and risk factors of unwanted sexual activity initiated by peers for 1,149 adolescent females. Twenty percent of sample reported some type of unwanted sexual contact in past year. Over one-third of this group reported having been forced to have sexual intercourse. Boyfriends were most commonly reported perpetrators followed by…

  11. Incidence of Active Tuberculosis and Cohort Retention Among Adolescents in Western Kenya

    NARCIS (Netherlands)

    Nduba, Videlis; van't Hoog, Anna H.; Mitchell, Ellen M. H.; Borgdorff, Martien; Laserson, Kayla F.

    2018-01-01

    Setting: Siaya County, with the highest tuberculosis notification rates in Kenya. Objectives: To determine the incidence of active tuberculosis and 1-year cohort retention in 12-18-year-old adolescents, in preparation for phase III tuberculosis vaccine trials. Methods: Adolescents were enrolled and

  12. 32 CFR 634.52 - Search incident to impoundment based on criminal activity.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Search incident to impoundment based on criminal activity. 634.52 Section 634.52 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Impounding...

  13. Cancer patients' experiences of nurses' behaviour and health promotion activities: a critical incident analysis.

    Science.gov (United States)

    Björklund, M; Fridlund, B

    1999-12-01

    Patients with head and neck cancer report several disease- and health-related problems before, during and a long time after completed treatment. Nurses have an important role in educating/supporting these patients about/through the disease and treatment so that they can attain well-being. This study describes the cancer patients' experiences of nurses' behaviour in terms of critical incidents after nurses had given them care to promote health. The study had a qualitative, descriptive design and the method used was the critical incident technique. Twenty-one informants from the Nordic countries diagnosed with head and neck cancer were strategically selected. It was explained to the informants what a critical incident implies before the interviews took place; this was defined as a major event of great importance, an incident, which the informants still remember, due to its great importance for the outcome of their health and well-being. The nurses' behaviour was examined, and critical incidents were involved in 208 cases-150 positive and 58 negative ones-the number of incidents varying between three and 20 per informant. The nurses' health promotion activities or lack of such activities based on the patients' disease, treatment and symptoms, consisted of informing and instructing the patients as well as enabling their participation. Personal consideration and the nurses' cognisance, knowledge, competence, solicitude, demeanour and statements of understanding were found to be important. Continuous health promotion nursing interventions were of considerable value for the majority of this group of cancer patients. Oncology nurses could reconfirm and update the care of head and neck cancer patients by including health promotion activities in individual care plans. By more frequent use of health promotion models, such as the empowerment model, the nurses could identify and focus on those individuals who needed to alter their life-style as well as tailor their approach

  14. Eficiência de uso da radiação fotossinteticamente ativa pela cultura do tomateiro em diferentes ambientes Use efficiency of photosynthetically active radiation by tomato plants grown in different environments

    Directory of Open Access Journals (Sweden)

    Bernadete Radin

    2003-09-01

    Full Text Available A produção de biomassa pelas culturas está relacionada à quantidade de radiação fotossinteticamente ativa interceptada e absorvida pelas folhas, bem como à eficiência com que estas convertem a energia radiante em energia química, pela fotossíntese. O objetivo deste trabalho foi avaliar a eficiência de uso da radiação fotossinteticamente ativa pelo tomateiro (Lycopersicon esculentum Mill. cultivado em diferentes ambientes. Os experimentos foram realizados em estufa de plástico com e sem tela lateral antiinsetos e fora da estufa, em duas épocas (primavera-verão e verão-outono, no ano agrícola de 1999/2000. Mediu-se a matéria seca aérea e o índice de área foliar ao longo dos dois ciclos, assim como os fluxos de radiação incidente e transmitida. O ambiente em estufa com tela lateral antiinsetos teve menos radiação incidente e maior eficiência de seu uso: 0,44 e 0,60 g de matéria seca mol-1, nas primeira e segunda épocas, respectivamente. No ambiente fora da estufa, com mais radiação incidente, houve menor eficiência de seu uso (0,30 e 0,32 g mol-1, enquanto no ambiente em estufa sem tela lateral antiinsetos, foram obtidos valores intermediários de eficiência de uso da radiação (0,45 e 0,53 g mol-1.Crop biomass production is related to the amount of photosynthetically active radiation intercepted and absorbed by the leaves, as well as to their efficiency of conversion of this radiant energy into chemical energy through photosynthesis. The objective of this study was to evaluate the radiation use efficiency by tomato plants (Lycopersicon esculentum Mill. grown in different environments. Experiments were carried out in plastic-covered greenhouses with and without antiinsects screens and at open air plots, in different growth periods (spring-summer and summer-autumn during the 1999/2000 crop season. Measurements of dry above-ground biomass and leaf area index throughout both crop cycles were performed, and the

  15. Effect of the Absorbed Photosynthetically Active Radiation Estimation Error on Net Primary Production Estimation - A Study with MODIS FPAR and TOMS Ultraviolet Reflective Products

    International Nuclear Information System (INIS)

    Kobayashi, H.; Matsunaga, T.; Hoyano, A.

    2002-01-01

    Absorbed photosynthetically active radiation (APAR), which is defined as downward solar radiation in 400-700 nm absorbed by vegetation, is one of the significant variables for Net Primary Production (NPP) estimation from satellite data. Toward the reduction of the uncertainties in the global NPP estimation, it is necessary to clarify the APAR accuracy. In this paper, first we proposed the improved PAR estimation method based on Eck and Dye's method in which the ultraviolet (UV) reflectivity data derived from Total Ozone Mapping Spectrometer (TOMS) at the top of atmosphere were used for clouds transmittance estimation. The proposed method considered the variable effects of land surface UV reflectivity on the satellite-observed UV data. Monthly mean PAR comparisons between satellite-derived and ground-based data at various meteorological stations in Japan indicated that the improved PAR estimation method reduced the bias errors in the summer season. Assuming the relative error of the fraction of PAR (FPAR) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) to be 10%, we estimated APAR relative errors to be 10-15%. Annual NPP is calculated using APAR derived from MODIS/ FPAR and the improved PAR estimation method. It is shown that random and bias errors of annual NPP in a 1 km resolution pixel are less than 4% and 6% respectively. The APAR bias errors due to the PAR bias errors also affect the estimated total NPP. We estimated the most probable total annual NPP in Japan by subtracting the bias PAR errors. It amounts about 248 MtC/yr. Using the improved PAR estimation method, and Eck and Dye's method, total annual NPP is 4% and 9% difference from most probable value respectively. The previous intercomparison study among using fifteen NPP models4) showed that global NPP estimations among NPP models are 44.4-66.3 GtC/yr (coefficient of variation = 14%). Hence we conclude that the NPP estimation uncertainty due to APAR estimation error is small

  16. Nutrition and physical activity influence on breast cancer incidence and outcome.

    Science.gov (United States)

    Chlebowski, Rowan T

    2013-08-01

    To provide a current perspective on nutrition and physical activity influence on breast cancer. A comprehensive literature review was conducted and selective presentation of findings follows. While some observational studies have associated higher dietary fat intake with higher breast cancer incidence, two full-scale randomized, clinical trials of dietary fat intake reduction programs were negative. However, a lifestyle intervention targeting fat intake reduction in the Women's Intervention Nutrition Study (WINS), resulted in weight loss and also reduced breast cancer recurrences in women with early stage disease. Observational studies evaluating specific nutrient intakes and dietary supplements have provided mixed results. Several observational studies find women with early stage breast cancer with lower 25-hydroxyvitamin D levels at higher recurrence risk, a finding requiring cautious interpretation. The lifestyle factor most strongly and consistently associated with both breast cancer incidence and breast cancer recurrence risk is physical activity. A meta-analyses of observational studies supports the concept that moderate recreational physical activity (about 3-4 h walking per week) may reduce breast cancer incidence and that women with early stage breast cancer who increased or maintain their physical activity may have lower recurrence risk as well. Feasibility of achieving increased physical activity and weight loss in women with early-stage breast cancer has been established. Two full-scale randomized clinical trials are evaluating weight loss/maintenance and increased physical activity in relation to recurrence risk in women with early-stage, resected breast cancer. Dietary intake may influence breast cancer but influence is difficult to separate from influence of body weight. A consistent body of observational study evidence suggests higher physical activity has favorable influence on breast cancer incidence and outcome. While awaiting definitive evidence

  17. Physical activity and incidence of sarcopenia: the population-based AGES—Reykjavik Study

    Science.gov (United States)

    Mijnarends, Donja M.; Koster, Annemarie; Schols, Jos M. G. A.; Meijers, Judith M. M.; Halfens, Ruud J. G.; Gudnason, Vilmundur; Eiriksdottir, Gudny; Siggeirsdottir, Kristin; Sigurdsson, Sigurdur; Jónsson, Pálmi V.; Meirelles, Osorio; Harris, Tamara

    2016-01-01

    Background: the prevalence of sarcopenia increases with age. Physical activity might slow the rate of muscle loss and therewith the incidence of sarcopenia. Objective: to examine the association of physical activity with incident sarcopenia over a 5-year period. Design: data from the population-based Age, Gene/Environment, Susceptibility–Reykjavik Study were used. Setting: people residing in the Reykjavik area at the start of the study. Subjects: the study included people aged 66–93 years (n = 2309). Methods: the amount of moderate–vigorous physical activity (MVPA) was assessed by a self-reported questionnaire. Sarcopenia was identified using the European Working Group on Sarcopenia in Older People algorithm, including muscle mass (computed tomography imaging), grip strength (computerised dynamometer) and gait speed (6 m). Results: mean age of the participants was 74.9 ± 4.7 years. The prevalence of sarcopenia was 7.3% at baseline and 16.8% at follow-up. The incidence proportion of sarcopenia over 5 years was 14.8% in the least-active individuals and 9.0% in the most-active individuals. Compared with the least-active participants, those reporting a moderate–high amount of MVPA had a significantly lower likelihood of incident sarcopenia (OR = 0.64, 95% CI 0.45–0.91). Participants with a high amount of MVPA had higher baseline levels of muscle mass, strength and walking speed, but baseline MVPA was not associated with the rate of muscle loss. Conclusion: a higher amount of MVPA seems to contribute to counteracting the development of sarcopenia. To delay the onset of sarcopenia and its potential adverse outcomes, attention should be paid to increasing physical activity levels in older adults. PMID:27189729

  18. Association of physical workload and leisure time physical activity with incident mobility limitations

    DEFF Research Database (Denmark)

    Mänty, M; Møller, A; Nilsson, C

    2014-01-01

    on Work, Unemployment and Health. Physical workload was reported at baseline and categorised as light, moderate or heavy. Baseline leisure time physical activity level was categorised as sedentary or active following the current recommendations on physical activity. Incidence of mobility limitations...... with higher workload regardless of level of leisure time physical activity, although the risks tended to be higher among those with sedentary leisure time compared with their active counterparts. All in all, the risk for onset of mobility limitations was highest among those with heavy workload combined...... with sedentary leisure time and lowest among those with light workload combined with active leisure time. CONCLUSIONS: Although leisure time physical activity prevents development of mobility decline, high workload seems to accelerate the progression of mobility limitations among both those with active...

  19. Incidence of Poverty and the Role of Non-Farm Activities

    International Nuclear Information System (INIS)

    Fatima, A.

    2015-01-01

    The incidence of poverty, poverty gap and the severity of poverty for the nine agro-climatic zones of the country (rice/wheat Punjab, mixed Punjab, cotton/wheat Punjab, low intensity Punjab, Barani Punjab, cotton/wheat Sindh, rice other Sindh, Khyber Pakhtunkhwa and Balochistan) were calculated for farming and non-farming households. The indices of poverty were also measured for households that only did farming, undertook farming and non-farm activities and those that did no farming in the various agro-climatic zones. Finally, incidence and severity of poverty as well as the spread of income among the poor for non-farm wage earners, farm wage earners, non-farm self-employed and the crop cultivators in the nine agro-climatic zones of rural Pakistan was also carried out. The relationship between incidence of poverty and non-farm activities is ambivalent with non-farm households being better off in regions that are less fertile. The incidence of poverty was highest amongst farm wage workers, followed by non-farm wage workers, non-farm self-employed and lastly crop cultivators. (author)

  20. Incidence of school failure according to baseline leisure-time physical activity practice: prospective study.

    Science.gov (United States)

    Rombaldi, Airton J; Clark, Valerie L; Reichert, Felipe F; Araújo, Cora L P; Assunção, Maria C; Menezes, Ana M B; Horta, Bernardo L; Hallal, Pedro C

    2012-12-01

    To evaluate the prospective association between leisure-time physical activity practice at 11 years of age and incidence of school failure from 11 to 15 years of age. The sample comprised >4,300 adolescents followed up from birth to 15 years of age participating in a birth cohort study in Pelotas, Brazil. The incidence of school failure from age 11 to 15 years was calculated by first excluding from the analyses all subjects who experienced a school failure before 11 years of age, and then categorizing as "positive" all those who reported repeating a grade at school from 11 to 15 years of age. Leisure-time physical activity was measured using a validated questionnaire. The incidence of school failure was 47.9% among boys and 38.2% among girls. Adolescents in the top quartile of leisure-time physical activity practice at 11 years of age had a higher likelihood of school failure (OR: 1.36; 95% CI: 1.06, 1.75) compared with the least active adolescents. In adjusted analyses stratified by sex, boys in the top quartile of leisure-time physical activity practice at 11 years of age were also more likely to have failed at school from age 11 to 15 years (OR: 1.60; 95% CI: 1.09, 2.33). Adolescents allocating >1,000 min/wk to leisure-time physical activity were more likely to experience a school failure from 11 to 15 years of age. Although this finding does not advocate against physical activity promotion, it indicates that excess time allocated to physical activity may jeopardize school performance among adolescents. Copyright © 2012 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  1. The Incidence of Primary Hip Osteoarthritis in Active Duty US Military Servicemembers

    Science.gov (United States)

    2009-04-15

    the hip and knee joint in retired football players. Acta Orthop Scand 1980;51:925–7. 36. Kujala UM, Kaprio J, Sarno S. Osteoarthritis of weightbearing...The Incidence of Primary Hip Osteoarthritis in Active Duty US Military Servicemembers DANIELLE L. SCHER,1 PHILIP J. BELMONT, JR.,1 SALLY MOUNTCASTLE...2 AND BRETT D. OWENS1 Objective. Although multiple studies have reported the prevalence of primary hip osteoarthritis (OA), little has been reported

  2. Mannose-6-Phosphate Reductase, a Key Enzyme in Photoassimilate Partitioning, Is Abundant and Located in the Cytosol of Photosynthetically Active Cells of Celery (Apium graveolens L.) Source Leaves.

    Science.gov (United States)

    Everard, J. D.; Franceschi, V. R.; Loescher, W. H.

    1993-06-01

    Mannitol, a major photosynthetic product and transport carbohydrate in many plants, accounts for approximately 50% of the carbon fixed by celery (Apium graveolens L.) leaves. Previous subfractionation studies of celery leaves indicated that the enzymes for mannitol synthesis were located in the cytosol, but these data are inconsistent with that published for the sites of sugar alcohol synthesis in other families and taxa, including apple (Malus) and a brown alga (Fucus). Using antibodies to a key synthetic enzyme, NADPH-dependent mannose-6-phosphate reductase (M6PR), and immunocytochemical techniques, we have resolved both the inter-cellular and intracellular sites of mannitol synthesis. In leaves, M6PR was found only in cells containing ribulose-1,5-bisphosphate carboxylase/oxygenase. M6PR was almost exclusively cytosolic in these cells, with the nucleus being the only organelle to show labeling. The key step in transport carbohydrate biosynthesis that is catalyzed by M6PR displays no apparent preferential association with vascular tissues or with the bundle sheath. These results show that M6PR and, thus, mannitol synthesis are closely associated with the distribution of photosynthetic carbon metabolism in celery leaves. The principal role of M6PR is, therefore, in the assimilation of carbon being exported from the chloroplast, and it seems unlikely that this enzyme plays even an indirect role in phloem loading of mannitol.

  3. Effect of light on the content of photosynthetically active pigments in plants. Pt. 4. Chromatic adaption in blue-green algae Anabaena cylindrica and A. variabilis

    Energy Technology Data Exchange (ETDEWEB)

    Czeczuga, B.

    1986-07-15

    The photosynthetic pigments (chlorophyll a, carotenoids and phycobiliprotein pigments) of two species of the genus Anabaena grown in white, red, yellow, green and blue light were examined. The highest concentration of the cells was observed in the sample with red light in case of the both species, and the smallest with blue light. The biggest amounts of chlorophyll a and carotenoids were included in the cells of samples with the yellow and the smallest in case of the red light. The ratio of two phycobiliproteins is as follows: - in Anabaena cylindrica: the highest amount of C-phycocyanin in the cells was observed in the case of the red light, and C-phycoerytherin was found in the blue light; - in Anabaena variabiles: the highest amount of C-phycocyanien in the cells was found in case of the yellow light, and allophycocyanin was found in the blue light.

  4. Growth, photosynthetic pigments and production of essential oil of long-pepper under different light conditions.

    Science.gov (United States)

    Lima, Vandimilli A; Pacheco, Fernanda V; Avelar, Rafaella P; Alvarenga, Ivan C A; Pinto, José Eduardo B P; Alvarenga, Amauri A DE

    2017-01-01

    Piper hispidinervum C. DC. is popularly known as long-pepper and it owns a commercial value due to the essential oil it produces. Long-pepper oil is rich in safrole and eugenoln components that have insecticidal, fungicidal and bactericidal activity. It has been establish that to medicinal plants light influences not only growth but also essential oil production. The growth, the content of photosynthetic pigments and the essential oil production of Piper hispidinervum at greenhouses with different light conditions was evaluated. The treatments were characterized by cultivation of plants for 180 days under different light conditions, produced by shading greenhouses with 50% and 30% of natural incident irradiance, two colored shading nets red (RN) and blue (BN) both blocking 50% of the incident radiation and one treatment at full-sun (0% of shade). The results showed that the treatments of 50% shade and RN and BN were the ones which stimulated the greater growth. Blue and red light also had the best production of photosynthetic pigments. Essential oil yielded more under full sun therefore this is the most indicated condition to produce seedlings for the chemical and pharmaceutical industry.

  5. Growth, photosynthetic pigments and production of essential oil of long-pepper under different light conditions

    Directory of Open Access Journals (Sweden)

    VANDIMILLI A. LIMA

    Full Text Available ABSTRACT Piper hispidinervum C. DC. is popularly known as long-pepper and it owns a commercial value due to the essential oil it produces. Long-pepper oil is rich in safrole and eugenoln components that have insecticidal, fungicidal and bactericidal activity. It has been establish that to medicinal plants light influences not only growth but also essential oil production. The growth, the content of photosynthetic pigments and the essential oil production of Piper hispidinervum at greenhouses with different light conditions was evaluated. The treatments were characterized by cultivation of plants for 180 days under different light conditions, produced by shading greenhouses with 50% and 30% of natural incident irradiance, two colored shading nets red (RN and blue (BN both blocking 50% of the incident radiation and one treatment at full-sun (0% of shade. The results showed that the treatments of 50% shade and RN and BN were the ones which stimulated the greater growth. Blue and red light also had the best production of photosynthetic pigments. Essential oil yielded more under full sun therefore this is the most indicated condition to produce seedlings for the chemical and pharmaceutical industry.

  6. Ecology and molecular genetics of anoxygenic photosynthetic arsenite oxidation by arxA

    OpenAIRE

    Hernandez-Maldonado, Jaime

    2017-01-01

    Thesis statement:Anoxygenic photosynthetic arsenite oxidation encoded by arxA is a bacterial arsenic metabolism that contributes to the biogeochemical cycle of arsenic in extreme environments.Abstract:This dissertation provides molecular genetics and environmental insight into the poorly-understood phenomenon of a photosynthetic microbial metabolism fueled by arsenic. The hypothesis is that arxA is critical for photosynthetic arsenite oxidation and actively found in the environment, which ha...

  7. Tectonics and the photosynthetic habitable zone (Invited)

    Science.gov (United States)

    Sleep, N. H.

    2009-12-01

    The traditional habitable zone lies between an inner stellar radius where the surface of the planet becomes too hot for liquid water carbon-based life and on outer radius, where the surface freezes. It is effectively the zone where photosynthesis is feasible. The concept extends to putative life on objects with liquid methane at the surface, like Titan. As a practical matter, photosynthesis leaves detectable biosignatures in the geological record; black shale on the Earth indicates that sulfide and probably FeO based photosynthesis existed by 3.8 Ga. The hard crustal rocks and the mantle sequester numerous photosynthetic biosignatures. Photosynthesis can produce detectable free oxygen with ozone in the atmosphere of extrasolar planets. In contrast, there is no outer limit for subsurface life in large silicate objects. Pre-photosynthetic niches are dependable but meager and not very detectable at great antiquity or great distance, with global productivity less than 1e-3 of the photosynthetic ones. Photosynthetic organisms have bountiful energy that modifies their surface environment and even tectonics. For example, metamorphic rocks formed at the expense of thick black shale are highly radioactive and hence self-fluxing. Active tectonics with volcanism and metamorphism prevents volatiles from being sequestered in the subsurface as on Mars. A heat-pipe object, like a larger Io, differs from the Earth in that the volatiles return to the deep interior distributed within massive volcanic deposits rather than concentrated in the shallow oceanic crust. One the Earth, the return of water to the surface by arc volcanoes controls its mantle abundance at the transition between behaving as a trace element and behaving as a major element that affects melting. The ocean accumulates the water that the mantle and crust do not take. The Earth has the “right” amount of water that erosion/deposition and tectonics both tend to maintain near sea level surfaces. The mantle contains

  8. Incidence, clinical presentation, and outcome of HIV-1-associated cryptococcal meningitis during the highly active antiretroviral therapy era

    DEFF Research Database (Denmark)

    Touma, Madeleine; Rasmussen, Line D; Martin-Iguacel, Raquel

    2017-01-01

    BACKGROUND: Human immunodeficiency virus (HIV) infection with advanced immunosuppression predisposes to cryptococcal meningitis (CM). We describe the incidence, clinical presentation, and outcome of CM in HIV-infected individuals during the highly active antiretroviral therapy (HAART) era. METHODS...

  9. Progression of plasminogen activator inhibitor-1 and fibrinogen levels in relation to incident type 2 diabetes.

    Science.gov (United States)

    Festa, Andreas; Williams, Ken; Tracy, Russell P; Wagenknecht, Lynne E; Haffner, Steven M

    2006-04-11

    Several studies have shown that fibrinolytic and coagulation abnormalities as well as low-grade inflammation predict cardiovascular disease and type 2 diabetes. We studied in the Insulin Resistance Atherosclerosis Study the relation of incident diabetes to dynamic changes of plasminogen activator inhibitor-1 (PAI-1) and fibrinogen. After a follow-up of 5.2 years, diabetes developed in 140 (16.6%) of 843 individuals (57% women; mean age [range], 54.7 [40, 69] years) (converters versus nonconverters). Baseline and follow-up levels of PAI-1 and fibrinogen (demographically and smoking adjusted) were higher in converters versus nonconverters (mean [SE]): at baseline, 23.7 ng/mL (1.5) versus 14.5 (0.4) and 286.2 mg/dL (4.8) versus 273.6 (2.1); at follow-up, 45.3 ng/mL (3.2) versus 25.9 (0.8) and 292.0 mg/dL (5.6) versus 275.2 (2.5); all P<0.05. In a demographically and smoking-adjusted logistic regression model, the change in PAI-1 was related to incident diabetes (OR for a 1-SD change [CI], 1.75 [1.37, 2.22]; P<0.001) after adjusting for baseline PAI-1 levels. After further adjusting for insulin sensitivity (SI) or waist, change in PAI-1 remained significantly related to incident diabetes (OR, 1.66 [1.28, 2.15], and 1.64 [1.28, 2.10]; P<0.001). In contrast, change in fibrinogen was not significantly related to incident diabetes. Progression of PAI-1 levels over time, in addition to high baseline PAI-1 levels, is associated with incident diabetes. PAI-1 levels (but not fibrinogen) further increase with the rising glucose levels and the development of diabetes. These findings extend the current knowledge on the relation of fibrinolysis and coagulation abnormalities to the development of type 2 diabetes.

  10. Structural and Functional Hierarchy in Photosynthetic Energy Conversion—from Molecules to Nanostructures

    Science.gov (United States)

    Szabó, Tibor; Magyar, Melinda; Hajdu, Kata; Dorogi, Márta; Nyerki, Emil; Tóth, Tünde; Lingvay, Mónika; Garab, Győző; Hernádi, Klára; Nagy, László

    2015-12-01

    Basic principles of structural and functional requirements of photosynthetic energy conversion in hierarchically organized machineries are reviewed. Blueprints of photosynthesis, the energetic basis of virtually all life on Earth, can serve the basis for constructing artificial light energy-converting molecular devices. In photosynthetic organisms, the conversion of light energy into chemical energy takes places in highly organized fine-tunable systems with structural and functional hierarchy. The incident photons are absorbed by light-harvesting complexes, which funnel the excitation energy into reaction centre (RC) protein complexes containing redox-active chlorophyll molecules; the primary charge separations in the RCs are followed by vectorial transport of charges (electrons and protons) in the photosynthetic membrane. RCs possess properties that make their use in solar energy-converting and integrated optoelectronic systems feasible. Therefore, there is a large interest in many laboratories and in the industry toward their use in molecular devices. RCs have been bound to different carrier matrices, with their photophysical and photochemical activities largely retained in the nano-systems and with electronic connection to conducting surfaces. We show examples of RCs bound to carbon-based materials (functionalized and non-functionalized single- and multiwalled carbon nanotubes), transitional metal oxides (ITO) and conducting polymers and porous silicon and characterize their photochemical activities. Recently, we adapted several physical and chemical methods for binding RCs to different nanomaterials. It is generally found that the P+(QAQB)- charge pair, which is formed after single saturating light excitation is stabilized after the attachment of the RCs to the nanostructures, which is followed by slow reorganization of the protein structure. Measuring the electric conductivity in a direct contact mode or in electrochemical cell indicates that there is an

  11. THE INFLUENCE OF GRAMOXONE HERBICIDE ON THE CONTENT OF THE PHOTOSYNTHETIC PIGMENTS IN ZEA MAYS

    Directory of Open Access Journals (Sweden)

    Antoanela Patras

    2007-08-01

    Full Text Available The active substance of Gramoxone herbicide is interacting with plant’s photosynthetic systems, playing the role of final acceptor of the photosynthetic electrons. Except this known mode of action, it has been also observed the inhibitory action on the protoporphyrinogen oxidase – essential enzyme for chlorophylls biosynthesis, and also the decrease of photosynthetic pigment’s concentration in some spontaneous plants. Based on these prerequisites, the present study demonstrates the decrease of the photosynthetic pigment’s content in Zea mays in the presence of Gramoxone.

  12. Photosynthetic characteristics of Lycoris aurea and monthly ...

    African Journals Online (AJOL)

    The leaf photosynthetic characteristics of Lycoris aurea, the monthly dynamics in lycorine and galantamine contents in its bulb and the correlation among the photosynthetic characteristics and the lycorine and galantamine during the annual growth period were studied by using LI-6400 portable photosynthetic measurement ...

  13. The effect of micronutrient supplementation on active TB incidence early in HIV infection in Botswana

    Directory of Open Access Journals (Sweden)

    Campa A

    2017-07-01

    Full Text Available Adriana Campa,1 Marianna K Baum,1 Hermann Bussmann,2 Sabrina Sales Martinez,1 Mansour Farahani,3 Erik van Widenfelt,2 Sikhulile Moyo,2,3 Joseph Makhema,2 Max Essex,2,3 Richard Marlink3 1Department of Dietetics and Nutrition, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL, USA; 2Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana; 3The Harvard T.H. Chan School of Public Health, Boston, MA, USA Background: Coinfection with active tuberculosis (TB is one of the leading causes of death in people living with HIV (PLWH in Africa. This investigation explores the role of micronutrient supplementation in preventing active TB in PLWH. Methods: A randomized trial of nutritional supplementation was conducted among antiretroviral-naïve (without previous antiretroviral treatment [ART] HIV-infected people in Botswana between 2004 and 2009. The study had a factorial design with four arms: the selenium (Se alone arm, the multivitamins (MVT alone arm that contained vitamin B complex and vitamins C and E, the combined Se+MVT group and the placebo group. Those participants with prior or current active TB were excluded, as were participants with advanced HIV disease (CD4 <250 cells/µL or who had already qualified for ART. HIV-positive adults (N=878 were followed monthly for study pill dispensation, every 3 months for CD4 cell count and every 6 months for viral load during 24 months or until they were started on ART. Results: The participants’ characteristics were not significantly different among the four groups at baseline. Supplementation with Se alone (hazard ratio =0.20, 95% confidence interval: 0.04, 0.95, P=0.043 and the two combined SE groups (Se and Se+MVT had significantly lower risk of developing incident TB disease compared with placebo in multivariate adjusted models (hazard ratio=0.32, 95% confidence interval: 0.11, 0.93, P=0.036. Multivitamins alone did not affect the incidence of TB

  14. Sleeping, TV, Cognitively Stimulating Activities, Physical Activity, and Attention-Deficit Hyperactivity Disorder Symptom Incidence in Children: A Prospective Study.

    Science.gov (United States)

    Peralta, Gabriela P; Forns, Joan; García de la Hera, Manuela; González, Llúcia; Guxens, Mònica; López-Vicente, Mónica; Sunyer, Jordi; Garcia-Aymerich, Judith

    2018-04-01

    To analyze associations between time spent sleeping, watching TV, engaging in cognitively stimulating activities, and engaging in physical activity, all at 4 years, and (1) attention-deficit/hyperactivity disorder (ADHD) symptoms and (2) behavior problems, both assessed at 7 years, in ADHD-free children at baseline. In total, 817 participants of the Infancia y Medio Ambiente birth cohort, without ADHD at baseline, were included. At the 4-year follow-up, parents reported the time that their children spent sleeping, watching TV, engaging in cognitively stimulating activities, and engaging in physical activity. At the 7-year follow-up, parents completed the Conners' Parent Rating Scales and the Strengths and Difficulties Questionnaire, which measure ADHD symptoms and behavior problems, respectively. Negative binomial regression models were used to assess associations between the activities at 4 years and ADHD symptoms and behavior problems at 7 years. Children (48% girls) spent a median (p25-p75) of 10 (10-11) hours per day sleeping, 1.5 (0.9-2) hours per day watching TV, 1.4 (0.9-1.9) hours per day engaging in cognitively stimulating activities, and 1.5 (0.4-2.3) hours per day engaging in physical activity. Longer sleep duration (>10 hours per day) was associated with a lower ADHD symptom score (adjusted incidence rate ratio = 0.97, 95% confidence interval, 0.95-1.00). Longer time spent in cognitively stimulating activities (>1 hours per day) was associated with lower scores of both ADHD symptoms (0.96, 0.94-0.98) and behavior problems (0.89, 0.83-0.97). Time spent watching TV and engaging in physical activity were not associated with either outcomes. A shorter sleep duration and less time spent in cognitively stimulating activities were associated with an increased risk of developing ADHD symptoms and behavior problems.

  15. Associations between active shooter incidents and gun ownership and storage among families with young children in the United States.

    Science.gov (United States)

    Morrissey, Taryn W

    2017-07-01

    The presence of firearms and their unsafe storage in the home can increase risk of firearm-related death and injury, but public opinion suggests that firearm ownership is a protective factor against gun violence. This study examined the effects of a recent nearby active shooter incident on gun ownership and storage practices among families with young children. A series of regression models, with data from the nationally representative Early Childhood Longitudinal Study-Birth Cohort merged with the FBI's Active Shooter Incidents data collected in 2003-2006, were used to examine whether household gun ownership and storage practices differed in the months prior to and following an active shooter incident that occurred anywhere in the United States or within the same state. Approximately one-fifth of young children lived in households with one or more guns; of these children, only two-thirds lived in homes that stored all guns in locked cabinets. Results suggest that the experience of a recent active shooter incident was associated with an increased likelihood of storing all guns locked, with the magnitude dependent on the temporal and geographic proximity of the incident. The severity of the incident, defined as the number of fatalities, predicted an increase in storing guns locked. Findings suggest that public shootings change behaviors related to firearm storage among families with young children. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Kinetic characterization of the photosynthetic reaction centres in microalgae by means of fluorescence methodology

    NARCIS (Netherlands)

    Gargano, Immacolata; Olivieri, Giuseppe; Spasiano, Danilo; Andreozzi, Roberto; Pollio, Antonino; Marotta, Raffaele; Ambrosio, D' Nicola; Marzocchella, Antonio

    2015-01-01

    The kinetic characterization of the photosynthetic activity in autotrophic microalgae plays a key role in the design of optimized photobioreactors. This paper presents a procedure to assess kinetic parameters of a three-state photosynthetic reaction centres model. Four kinetic parameters of the

  17. Associations of Leisure-Time and Occupational Physical Activity and Cardiorespiratory Fitness With Incident and Recurrent Major Depressive Disorder, Depressive Symptoms, and Incident Anxiety in a General Population.

    Science.gov (United States)

    Baumeister, Sebastian E; Leitzmann, Michael F; Bahls, Martin; Dörr, Marcus; Schmid, Daniela; Schomerus, Georg; Appel, Katja; Markus, Marcello R P; Völzke, Henry; Gläser, Sven; Grabe, Hans-Jörgen

    2017-01-01

    Physical activity and cardiorespiratory fitness may help prevent depression and anxiety. Previous studies have been limited by error-prone measurements. We examined whether self-reported physical activity domains and peak exercise capacity (peakVO₂) are associated with incident and recurrent major depressive disorder (MDD), depressive symptoms, and anxiety disorders. This was a prospective population-based study of 1,080 adult men and women (25-83 years) with a median follow-up of 4.5 years and measures of physical activity during leisure time, sports, and work (Baecke questionnaire); a measure of depressive symptoms (Beck Depression Inventory II); symptom-limited cycle ergometer testing (peakVO₂, oxygen uptake at anaerobic threshold [VO₂@AT], maximum power output at peak exertion); and a structured psychiatric interview (Munich Composite International Diagnostic Interview). Baseline data were collected between 2002 and 2006, and follow-up data, between 2007 and 2010. After adjustment for age, sex, education, smoking, alcohol consumption, and waist circumference, the relative risks for incident MDD per standard deviation (SD) increase in leisure-time physical activity, physical activity during sport, physical activity at work, peakVO₂, VO₂@AT, and maximum power output were 1.002 (95% confidence interval, 0.90 to 1.12), 1.02 (0.90 to 1.15), 0.94 (0.80 to 1.10), 0.71 (0.52 to 0.98), 0.83 (0.66 to 1.04), and 0.71 (0.52 to 0.96), respectively. PeakVO₂, VO₂@AT, and maximum power output were associated with recurrent MDD, depressive symptoms, and anxiety. PeakVO₂ was more strongly related to the co-occurrence of MDD and anxiety (adjusted odds ratio [OR] = 0.45 [0.24 to 0.84]) than depression or anxiety alone (OR = 0.71 [0.53 to 0.94]). Greater cardiorespiratory fitness but not domain-specific physical activity was associated with a lower incidence of MDD and clinical anxiety. © Copyright 2017 Physicians Postgraduate Press, Inc.

  18. Efeitos de herbicidas na atividade fotossintética e no crescimento de abacaxi (Ananas comossus Effects of herbicides on the photosynthetic activity of pineapple (Ananas comossus

    Directory of Open Access Journals (Sweden)

    M.G. Catunda

    2005-03-01

    Full Text Available O manejo de plantas daninhas na cultura do abacaxi é uma prática indispensável, sendo o controle químico cada vez mais utilizado, uma vez que permite o controle eficiente e não danifica as raízes da cultura. Todavia, há poucos trabalhos sobre interferência de herbicidas no crescimento da cultura; portanto, visando avaliar os efeitos de amicarbazone e diuron + paraquat, estes foram aplicados diretamente sobre as plantas, sendo os efeitos mensurados através da taxa de fluorescência da clorofila a e dos teores de clorofila a, clorofila b e carotenóides, além da avaliação de altura e biomassa seca de parte aérea (Wpa. O herbicida amicarbazone promoveu declínio nos teores de pigmentos fotossintéticos, não se verificando a mesma interferência para as variáveis altura e Wpa; no entanto, o herbicida diuron + paraquat foi letal para a cultura, haja vista a redução nos teores de clorofilas a e b e carotenóides, além da impossibilidade da medição da altura e Wpa (aos 120 DAT em função da morte das plantas aos 30 DAT, o que demonstra certa seletividade do amicarbazone à cultura do abacaxi.Weed management in pineapple crop is an indispensable practice, with chemical control being increasingly used since it allows efficient control without injury to the roots. Since little literature is available on herbicide interference in crop growth, the aim of this work was to evaluate the effects of the herbicides amicarbazone and diuron + paraquat applied directly on the plants. The herbicide effects were measured by the fluorescence rate of chlorophyll a and chlorophyll a, chlorophyll b and carotenoid contents, and by evaluating the height and dry biomass of the aerial part (Wpa. The application of amicarbazone reduced the photosynthetic pigment contents although the same interference in height and Wpa variables was not observed; however, diuron + paraquat herbicide caused the death of the pineapple plants, indicating a reduction in

  19. Recent events in NPPs and incident reporting system (IRS) activity. Working material

    International Nuclear Information System (INIS)

    1996-01-01

    The IAEA convened the 1996 Joint Meeting to Exchange Information on Recent Events in Nuclear Power Plants and the Technical Committee-Annual Meeting of the Incident Reporting System (IRS) national co-ordinators, organized jointly with the Nuclear Energy Agency (NEA) of the OECD in Paris, France from 22-26 April 1996. These consecutive meetings took place at the OECD Headquarters, 2 rue Andre Pascal. The main objective of the first meeting (22-24 April 1996) was to exchange and discuss information on recent events which occurred in NPPs. The second meeting (25-26 April 1996) was devoted to the IAEA and NEA activity in the framework of the IRS. The main issues of the programme at the meetings were as follows: in-depth discussion on NPP recent events, presented by the participants; panel discussion on operational safety experience issues identified by the participants; IAEA and NEA activities on IRS subjects in 1995-1996 and plans for the future; issues from the inter-agency's IRS Advisory Committee. Annexes I and II provide more information on the programme at the meetings. A list of participants is given in Annex III (50 participants from 22 countries and 3 international organization). Annexes IV and V provide information on national presentations on recent events. Figs, tabs

  20. Incidence of Bacteriocins Produced by Food-Related Lactic Acid Bacteria Active towards Oral Pathogens

    Directory of Open Access Journals (Sweden)

    Konstantinos Papadimitriou

    2013-02-01

    Full Text Available In the present study we investigated the incidence of bacteriocins produced by 236 lactic acid bacteria (LAB food isolates against pathogenic or opportunistic pathogenic oral bacteria. This set of LAB contained several strains (≥17% producing bacteriocins active against food-related bacteria. Interestingly only Streptococcus macedonicus ACA-DC 198 was able to inhibit the growth of Streptococcus oralis, Streptococcus sanguinis and Streptococcus gordonii, while Lactobacillus fermentum ACA-DC 179 and Lactobacillus plantarun ACA-DC 269 produced bacteriocins solely against Streptococcus oralis. Thus, the percentage of strains that were found to produce bacteriocins against oral bacteria was ~1.3%. The rarity of bacteriocins active against oral LAB pathogens produced by food-related LAB was unexpected given their close phylogenetic relationship. Nevertheless, when tested in inhibition assays, the potency of the bacteriocin(s of S. macedonicus ACA-DC 198 against the three oral streptococci was high. Fourier-transform infrared spectroscopy combined with principal component analysis revealed that exposure of the target cells to the antimicrobial compounds caused major alterations of key cellular constituents. Our findings indicate that bacteriocins produced by food-related LAB against oral LAB may be rare, but deserve further investigation since, when discovered, they can be effective antimicrobials.

  1. Effects of gibberellic acid on growth and photosynthetic pigments of ...

    African Journals Online (AJOL)

    The aim of this study was to improve growth performance by enhancing the photosynthetic pigments and enzyme carbonic anhydrase (CA) activity of Hibiscus sabdariffa L. (cv. Sabahia 17) under NaCl stress. Under non-saline condition, application of GA3 enhanced growth parameters (shoot length, shoot fresh weight (FW) ...

  2. Effect of ambient levels of ozone on photosynthetic components and ...

    African Journals Online (AJOL)

    Effect of ambient levels of ozone on photosynthetic components and radical scavenging system in leaves of African cowpea varieties. ... The O3-induced significant reduction in catalase activity was observed in Blackeye at vegetative and reproductive growth stages; and in Asontem at reproductive growth stage. On the other ...

  3. Influence of thermal light correlations on photosynthetic structures

    Science.gov (United States)

    de Mendoza, Adriana; Manrique, Pedro; Caycedo-Soler, Felipe; Johnson, Neil F.; Rodríguez, Ferney J.; Quiroga, Luis

    2014-03-01

    The thermal light from the sun is characterized by both classical and quantum mechanical correlations. These correlations have left a fingerprint on the natural harvesting structures developed through five billion years of evolutionary pressure, specially in photosynthetic organisms. In this work, based upon previous extensive studies of spatio-temporal correlations of light fields, we hypothesize that structures involving photosensitive pigments like those present in purple bacteria vesicles emerge as an evolutionary response to the different properties of incident light. By using burstiness and memory as measures that quantify higher moments of the photon arrival statistics, we generate photon-time traces. They are used to simulate absorption on detectors spatially extended over regions comparable to these light fields coherence length. Finally, we provide some insights into the connection between these photo-statistical features with the photosynthetic membrane architecture and the lights' spatial correlation. Facultad de Ciencias Uniandes.

  4. Association of DPP-4 activity with BMD, body composition, and incident hip fracture: the Cardiovascular Health Study.

    Science.gov (United States)

    Carbone, L D; Bůžková, P; Fink, H A; Robbins, J A; Bethel, M; Isales, C M; Hill, W D

    2017-05-01

    There was no association of plasma DPP-4 activity levels with bone mineral density (BMD), body composition, or incident hip fractures in a cohort of elderly community-dwelling adults. Dipeptidyl peptidase IV (DPP-4) inactivates several key hormones including those that stimulate postprandial insulin secretion, and DPP-4 inhibitors (gliptins) are approved to treat diabetes. While DPP-4 is known to modulate osteogenesis, the relationship between DPP-4 activity and skeletal health is uncertain. The purpose of the present study was to examine possible associations between DPP-4 activity in elderly subjects enrolled in the Cardiovascular Health Study (CHS) and BMD, body composition measurements, and incident hip fractures. All 1536 male and female CHS participants who had evaluable DXA scans and plasma for DPP-4 activity were included in the analyses. The association between (1) BMD of the total hip, femoral neck, lumbar spine, and total body; (2) body composition measurements (% lean, % fat, and total body mass); and (3) incident hip fractures and plasma levels of DPP-4 activity were determined. Mean plasma levels of DPP-4 activity were significantly higher in blacks (227 ± 78) compared with whites (216 ± 89) (p = 0.04). However, there was no significant association of DPP-4 activity with age or gender (p ≥ 0.14 for both). In multivariable adjusted models, there was no association of plasma DPP-4 activity with BMD overall (p ≥ 0.55 for all) or in gender stratified analyses (p ≥ 0.23). There was also no association of DPP-4 levels and incident hip fractures overall (p ≥ 0.24) or in gender stratified analyses (p ≥ 0.39). Plasma DPP-4 activity, within the endogenous physiological range, was significantly associated with race, but not with BMD, body composition, or incident hip fractures in elderly community-dwelling subjects.

  5. Diel oscillation in the optical activity of carotenoids in the absorption spectrum of Nannochloropsis.

    Science.gov (United States)

    Possa, Gabriela C; Santana, Hugo; Brasil, Bruno S A F; Roncaratti, Luiz F

    2017-03-01

    In this paper we show that the absorption spectrum of the microalgae Nannochloropsis oceanica exhibits changes in response to the modulation of incident light. A model was used to analyze the contribution of different active pigments to the total absorption in the photosynthetically active radiation region and suggested consistent diel oscillations in the optical activity of carotenoids.

  6. Incidence of various causes of vaginal discharge among sexually active females in age group 20-40 years

    Directory of Open Access Journals (Sweden)

    Puri K

    2003-03-01

    Full Text Available The present study was undertaken to know incidence of various causes of vaginal discharge in sexually active females of age group 20-40 years. One hundred sexually active females in the age group of 20-40 years, with vaginal discharge, were selected for this study at random. A detailed clinical history and a thorough examination of all the cases was done. After making the clinical diagnosis, appropriate tests for diagnosing candidiasis, trichomoniosis, gonorrhoea and bacterial vaginosis were done. The present study showed 45% incidence of bacterial voginosis, 31% vulvovaginalcandidiasis, 2% trichomoniasis, 3% gonorrhoea, 5% non-specific urogenital causes, and 14% with other causes.

  7. Active surveillance for methicillin-resistant Staphylococcus aureus (MRSA) decreases the incidence of MRSA bacteremia.

    Science.gov (United States)

    Shitrit, Pnina; Gottesman, Bat-Sheva; Katzir, Michal; Kilman, Avi; Ben-Nissan, Yona; Chowers, Michal

    2006-10-01

    To evaluate the influence of performance of active surveillance cultures for methicillin-resistant Staphylococcus aureus (MRSA) on the incidence of nosocomial MRSA bacteremia in an endemic hospital. Before-after trial. A 700-bed hospital. All patients admitted to the hospital who were at high risk for MRSA bacteremia. Performance of surveillance cultures for detection of MRSA were recommended for all patients at high risk, and contact isolation was implemented for patients with positive results of culture. Each MRSA-positive patient received one course of eradication treatment. We compared the total number of surveillance cultures, the percentage of surveillance cultures with positive results, and the number of MRSA bacteremia cases before the intervention (from January 2002 through February 2003) after the start of the intervention (from July 2003 through October 2004). The number of surveillance cultures performed increased from a mean of 272.57 cultures/month before the intervention to 865.83 cultures/month after the intervention. The percentage of surveillance cultures with positive results increased from 3.13% before to 5.22% after the intervention (P hidden reservoirs of MRSA. Contact isolation can prevent new colonization and infection and lead to a significant reduction of morbidity and healthcare costs.

  8. Trends in incidence of disability in activities of daily living among Chinese older adults, 1993-2006

    Science.gov (United States)

    Liang, Yajun; Welmer, Anna-Karin; Wang, Rui; Song, Aiqin; Fratiglioni, Laura; Qiu, Chengxuan

    2016-01-01

    BACKGROUND A decline in prevalence of disability in activities of daily living (ADL) among Chinese elderly people has been reported, but data on secular trends of incidence of ADL disability are sparse. OBJECTIVES We seek to investigate the time trends in incidence of ADL disability among Chinese older adults, and further, to explore factors potentially contributing to the trends. DESIGN A population-based prospective study. SETTING Participants were selected from nine provinces of China through a multistage, randomized, cluster sampling process. PARTICIPANTS We identified three consecutive cohorts of people aged ≥60 years within China Health and Nutrition Survey: cohort 1993-2000 (n=831), cohort 1997-2004 (n=1,091), and cohort 2000-2006 (n=1,152). MEASUREMENTS Disability in ADL was defined as inability to perform at least one of the five self-care activities, i.e., transferring, dressing, toileting, bathing, and feeding. Data were analyzed with Cox and generalized estimating equation models. RESULS The incidence (per 1,000 person-years) of ADL disability significantly decreased from 35.3 in 1993-2000 and 28.9 in 1997-2004 to 24.3 in 2000-2006 in Chinese older adults (Ptrend<.001). The incidence of ADL disability significantly decreased in both men and women, in young-old adults (aged 60-74 years), and in those living in rural area (Ptrend<.02) after controlling for multiple potential influential factors. Of the five ADL items, the decline in incidence of disability was significant in transferring (Ptrend<.001) and bathing (Ptrend=.002) and marginally significant in toileting (Ptrend=.061), but the incidence was stable in dressing (Ptrend=.384) and feeding (Ptrend=.258). CONCLUSION The incidence of ADL disability decreased from 1993 to 2006 among older adults in China, especially in transferring and bathing, independent of socio-demographics, lifestyles, and chronic health conditions. PMID:27682324

  9. Gender differences in incidence and determinants of disability in activities of daily living among elderly individuals: SABE study.

    Science.gov (United States)

    Alexandre, Tiago da Silva; Corona, Ligiana Pires; Nunes, Daniella Pires; Santos, Jair Lício Ferreira; Duarte, Yeda Aparecida de Oliveira; Lebrão, Maria Lúcia

    2012-01-01

    Determining the groups that are most susceptible to developing disability is essential to establishing effective prevention and rehabilitation strategies. The aim of the present study was to determine gender differences in the incidence of disability regarding activities of daily living (ADL) and determinants among elderly residents of Sao Paulo, Brazil. In 2000, 1634 elderly with no difficulties regarding ADL (modified Katz Index) were selected. These activities were reassessed in 2006 and disability was the outcome for the analysis of determinants. The following characteristics were analyzed at baseline: socio-demographic, behavioral, health status, medications, falls, hospitalizations, depressive symptoms, cognition, handgrip, mobility and balance. The incidence density was 42.4/1000 women/year and 17.5/1000 men/year. After adjusting for socioeconomic status and health conditions, women with chronic diseases and social vulnerability continued to have a greater incidence of disability. The following were determinants of the incidence of disability: age and depressive symptoms in both genders; stroke and slowness on the sit-and-stand test among men; and osteoarthritis and sedentary lifestyle among women. Better cognitive performance and handgrip strength were protective factors among men and women, respectively. Adverse clinical and social conditions determine differences between genders regarding the incidence of disability. Decreased mobility and balance and health conditions that affect the central nervous system or lead to impaired cognition disable men more, whereas a sedentary lifestyle, reduction in muscle strength and conditions that affect the osteoarticular system disable women more. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  10. Using Critical Incidents of Instructional Design and Multimedia Production Activities to Investigate Instructional Designers' Current Practices and Roles

    Science.gov (United States)

    Sugar, William A.; Luterbach, Kenneth J.

    2016-01-01

    Through consideration of critical incidents, this study analyzed 106 effective, ineffective and extraordinary instructional design and multimedia production (MP) activities discussed by 36 instructional design professionals. This evaluation provided insights into these professionals' best and not so best practices during the past 6 months.…

  11. Character, Incidence, and Predictors of Knee Pain and Activity After Infrapatellar Intramedullary Nailing of an Isolated Tibia Fracture

    NARCIS (Netherlands)

    Obremskey, William; Agel, Julie; Archer, Kristin; To, Philip; Tornetta, Paul; Bhandari, Mohit; Guyatt, Gordon; Sanders, David W.; Schemitsch, Emil H.; Swiontkowski, Marc; Walter, Stephen; Sprague, Sheila; Heels-Ansdell, Diane; Buckingham, Lisa; Leece, Pamela; Viveiros, Helena; Mignott, Tashay; Ansell, Natalie; Sidorkewicz, Natalie; Bombardier, Claire; Berlin, Jesse A.; Bosse, Michael; Browner, Bruce; Gillespie, Brenda; Jones, Alan; O'Brien, Peter; Poolman, Rudolf; Macleod, Mark D.; Carey, Timothy; Leitch, Kellie; Bailey, Stuart; Gurr, Kevin; Konito, Ken; Bartha, Charlene; Low, Isolina; MacBean, Leila V.; Ramu, Mala; Reiber, Susan; Strapp, Ruth; Tieszer, Christina; Kreder, Hans J.; Stephen, David J. G.; Axelrod, Terry S.; Yee, Albert J. M.; Richards, Robin R.; Finkelstein, Joel; Gofton, Wade; Murnaghan, John; Schatztker, Joseph; Ford, Michael; Bulmer, Beverly; Conlan, Lisa; Laflamme, G. Yves; Berry, Gregory; Beaumont, Pierre; Ranger, Pierre; Laflamme, Georges-Henri; Gagnon, Sylvain; Malo, Michel; Fernandes, Julio; Poirier, Marie-France; McKee, Michael D.; Waddell, James P.; Bogoch, Earl R.; Daniels, Timothy R.; McBroom, Robert R.; Vicente, Milena R.; Storey, Wendy; Wild, Lisa M.; McCormack, Robert; Perey, Bertrand; Goetz, Thomas J.; Pate, Graham; Penner, Murray J.; Panagiotopoulos, Kostas; Pirani, Shafique; Dommisse, Ian G.; Loomer, Richard L.; Stone, Trevor; Moon, Karyn; Zomar, Mauri; Webb, Lawrence X.; Teasdall, Robert D.; Birkedal, John Peter; Martin, David Franklin; Ruch, David S.; Kilgus, Douglas J.; Pollock, David C.; Harris, Mitchel Brion; Wiesler, Ethan Ron; Ward, William G.; Shilt, Jeffrey Scott; Koman, Andrew L.; Poehling, Gary G.; Kulp, Brenda; Creevy, William R.; Stein, Andrew B.; Bono, Christopher T.; Einhorn, Thomas A.; Brown, T. Desmond; Pacicca, Donna; Sledge, John B.; Foster, Timothy E.; Voloshin, Ilva; Bolton, Jill; Carlisle, Hope; Shaughnessy, Lisa; Obremskey, William T.; LeCroy, C. Michael; Meinberg, Eric G.; Messer, Terry M.; Craig, William L.; Dirschl, Douglas R.; Caudle, Robert; Harris, Tim; Elhert, Kurt; Hage, William; Jones, Robert; Piedrahita, Luis; Schricker, Paul O.; Driver, Robin; Godwin, Jean; Kregor, Philip James; Tennent, Gregory; Truchan, Lisa M.; Sciadini, Marcus; Shuler, Franklin D.; Driver, Robin E.; Nading, Mary Alice; Neiderstadt, Jacky; Vap, Alexander R.; Vallier, Heather A.; Patterson, Brendan M.; Wilber, John H.; Wilber, Roger G.; Sontich, John K.; Moore, Timothy Alan; Brady, Drew; Cooperman, Daniel R.; Davis, John A.; Cureton, Beth Ann; Mandel, Scott; Orr, R. Douglas; Sadler, John T. S.; Hussain, Tousief; Rajaratnam, Krishan; Petrisor, Bradley; Drew, Brian; Bednar, Drew A.; Kwok, Desmond C. H.; Pettit, Shirley; Hancock, Jill; Cole, Peter A.; Smith, Joel J.; Brown, Gregory A.; Lange, Thomas A.; Stark, John G.; Levy, Bruce A.; Swiontkowski, Marc F.; Garaghty, Mary J.; Salzman, Joshua G.; Schutte, Carol A.; Tastad, Linda; Vang, Sandy; Seligson, David; Roberts, Craig S.; Malkani, Arthur L.; Sanders, Laura; Dyer, Carmen; Heinsen, Jessica; Smith, Langan; Madanagopal, Sudhakar; Frantz-Bush, Linda; Coupe, Kevin J.; Tucker, Jeffrey J.; Criswell, Allen R.; Buckle, Rosemary; Rechter, Alan Jeffrey; Sheth, Dhiren Shaskikant; Urquart, Brad; Trotscher, Thea; Anders, Mark J.; Kowalski, Joseph M.; Fineberg, Marc S.; Bone, Lawrence B.; Phillips, Matthew J.; Rohrbacher, Bernard; Stegemann, Philip; Mihalko, William M.; Buyea, Cathy; Augustine, Stephen J.; Jackson, William Thomas; Solis, Gregory; Ero, Sunday U.; Segina, Daniel N.; Berrey, Hudson B.; Agnew, Samuel G.; Fitzpatrick, Michael; Campbell, Lakina C.; Derting, Lynn; McAdams, June; Goslings, J. Carel; Ponsen, Kees Jan; Luitse, Jan; Kloen, Peter; Joosse, Pieter; Winkelhagen, Jasper; Duivenvoorden, Raphaël; Teague, David C.; Davey, Joseph; Sullivan, J. Andy; Ertl, William J. J.; Puckett, Timothy A.; Pasque, Charles B.; Tompkins, John F.; Gruel, Curtis R.; Kammerlocher, Paul; Lehman, Thomas P.; Puffinbarger, William R.; Carl, Kathy L.; Weber, Donald W.; Jomha, Nadr M.; Goplen, Gordon R.; Masson, Edward; Beaupre, Lauren A.; Greaves, Karen E.; Schaump, Lori N.; Jeray, Kyle J.; Goetz, David R.; Westberry, David E.; Broderick, J. Scott; Moon, Bryan S.; Tanner, Stephanie L.; Powell, James N.; Buckley, Richard E.; Elves, Leslie; Connolly, Stephen; Abraham, Edward P.; Steele, Trudy; Ellis, Thomas; Herzberg, Alex; Brown, George A.; Crawford, Dennis E.; Hart, Robert; Hayden, James; Orfaly, Robert M.; Vigland, Theodore; Vivekaraj, Maharani; Bundy, Gina L.; Miclau, Theodore; Matityahu, Amir; Coughlin, R. Richard; Kandemir, Utku; McClellan, R. Trigg; Lin, Cindy Hsin-Hua; Karges, David; Cramer, Kathryn; Watson, J. Tracy; Moed, Berton; Scott, Barbara; Beck, Dennis J.; Orth, Carolyn; Puskas, David; Clark, Russell; Jones, Jennifer; Egol, Kenneth A.; Paksima, Nader; France, Monet; Wai, Eugene K.; Johnson, Garth; Wilkinson, Ross; Gruszczynski, Adam T.; Vexler, Liisa

    2016-01-01

    To study the activity and incidence of knee pain after sustaining an isolated tibia fracture treated with an infrapatellar intramedullary nail at 1 year. Retrospective review of prospective cohort. Multicenter Academic and Community hospitals. Four hundred thirty-seven patients with an isolated

  12. Abscisic Acid Induced Changes in Production of Primary and Secondary Metabolites, Photosynthetic Capacity, Antioxidant Capability, Antioxidant Enzymes and Lipoxygenase Inhibitory Activity of Orthosiphon stamineus Benth.

    Directory of Open Access Journals (Sweden)

    Mohd Hafiz Ibrahim

    2013-07-01

    Full Text Available An experiment was conducted to investigate and distinguish the relationships in the production of total phenolics, total flavonoids, soluble sugars, H2O2, O2−, phenylalanine ammonia lyase (PAL activity, leaf gas exchange, antioxidant activity, antioxidant enzyme activity [ascorbate peroxidase (APX, catalase (CAT, superoxide dismutase (SOD and Lipoxygenase inhibitory activity (LOX] under four levels of foliar abscisic acid (ABA application (0, 2, 4, 6 µM for 15 weeks in Orthosiphon stamineus Benth. It was found that the production of plant secondary metabolites, soluble sugars, antioxidant activity, PAL activity and LOX inhibitory activity was influenced by foliar application of ABA. As the concentration of ABA was increased from 0 to 6 µM the production of total phenolics, flavonoids, sucrose, H2O2, O2−, PAL activity and LOX inhibitory activity was enhanced. It was also observed that the antioxidant capabilities (DPPH and ORAC were increased. This was followed by increases in production of antioxidant enzymes APX, CAT and SOD. Under high application rates of ABA the net photosynthesis and stomatal conductance was found to be reduced. The production of primary and secondary metabolites displayed a significant positive relationship with H2O2 (total phenolics, r2 = 0.877; total flavonoids, r2 = 0.812; p ≤ 0.05 and O2− (total phenolics, r2 = 0.778; total flavonoids, r2 = 0.912; p ≤ 0.05. This indicated that increased oxidative stress at high application rates of ABA, improved the production of phytochemicals.

  13. Application of heat stress in situ demonstrates a protective role of irradiation on photosynthetic performance in alpine plants

    OpenAIRE

    Buchner, Othmar; STOLL, Magdalena; Karadar, Matthias; Kranner, Ilse; Neuner, Gilbert

    2014-01-01

    The impact of sublethal heat on photosynthetic performance, photosynthetic pigments and free radical scavenging activity was examined in three high mountain species, R hododendron ferrugineum, S enecio incanus and R anunculus glacialis using controlled in situ applications of heat stress, both in darkness and under natural solar irradiation. Heat treatments applied in the dark reversibly reduced photosynthetic performance and the maximum quantum efficiency of photosystem II (Fv/Fm), which rem...

  14. [Effects of reduced solar radiation on winter wheat flag leaf net photosynthetic rate].

    Science.gov (United States)

    Zheng, You-Fei; Ni, Yan-Li; Mai, Bo-Ru; Wu, Rong-Jun; Feng, Yan; Sun, Jian; Li, Jian; Xu, Jing-Xin

    2011-06-01

    Taking winter wheat Triticum aestivum L. (cv. Yangmai 13) as test material, a field experiment was conducted in Nanjing City to study the effects of simulated reduced solar radiation on the diurnal variation of winter wheat flag leaf photosynthetic rate and the main affecting factors. Five treatments were installed, i. e., 15% (T15), 20% (T20) , 40% (T40), 60% (T60), and 100% (CK) of total incident solar radiation. Reduced solar irradiance increased the chlorophyll and lutein contents significantly, but decreased the net photosynthetic rate (Pn). Under different solar irradiance, the diurnal variation of Pn had greater difference, and the daily maximum Pn was in the order of CK > T60 > T40 > T 20 > T15. In CK, the Pn exhibited a double peak diurnal curve; while in the other four treatments, the Pn showed a single peak curve, and the peak was lagged behind that of CK. Correlation analysis showed that reduced solar irradiance was the main factor affecting the diurnal variation of Pn, but the physiological parameters also played important roles in determining the diurnal variation of Pn. In treatments T60 and T40, the photosynthesis active radiation (PAR), leaf temperature (T1) , stomatal conductance (Gs) , and transpiration rate (Tr) were significantly positively correlated with Pn, suggesting their positive effects on Pn. The intercellular CO2 concentration (Ci) and stomatal limitation (Ls) had significant negative correlations with Pn in treatments T60 and T40 but significant positive correlations with Pn in treatments T20 and T15, implying that the Ci and Ls had negative (or positive) effects on Pn when the solar irradiance was higher (or lower) than 40% of incident solar irradiance.

  15. Photosynthetic light reactions at the gold interface

    NARCIS (Netherlands)

    Kamran, Muhammad

    2014-01-01

    In the project described in this thesis we studied a simple bio-electronic device for solar energy conversion by surface-assembly of photosynthetic pigment-protein complexes on a bare gold-electrode. Optical excitation of the photosynthetic pigments gives rise to charge separation in the so-called

  16. Photosynthetic characteristics of Lycoris aurea and monthly ...

    African Journals Online (AJOL)

    AJL

    2012-02-21

    Feb 21, 2012 ... The leaf photosynthetic characteristics of Lycoris aurea, the monthly dynamics in lycorine and galantamine contents in its bulb and the correlation among the photosynthetic characteristics and the lycorine and galantamine during the annual growth period were studied by using LI-6400 portable.

  17. Association of physical activity with body mass index, waist circumference and incidence of obesity in older adults.

    Science.gov (United States)

    Cárdenas Fuentes, Gabriela; Bawaked, Rowaedh Ahmed; Martínez González, Miguel Ángel; Corella, Dolores; Subirana Cachinero, Isaac; Salas-Salvadó, Jordi; Estruch, Ramón; Serra-Majem, Lluis; Ros, Emilio; Lapetra Peralta, José; Fiol, Miguel; Rekondo, Javier; Gómez-Gracia, Enrique; Tur Marí, Josep Antoni; Pinto Sala, Xavier; Babio, Nancy; Ortega, Carolina; Martínez, José Alfredo; Schröder, Helmut

    2018-03-15

    There is limited, and inconsistent, data on the prospective association between physical activity and surrogate markers of adiposity in older adults. We aim to determine the prospective association of leisure time physical activity (LTPA) with body mass index (BMI), waist circumference (WC) and the incidence of obesity. This prospective analysis included 7144 individuals with a mean age of 67 ± 6.2 years, from the PREvención con DIeta MEDiterránea (PREDIMED) study. BMI and WC were measured and LTPA was recorded using the Minnesota Leisure Time Physical Activity Questionnaire. Exposure and outcome variables were calculated as cumulative average of repeated measurements. Total LTPA was inversely associated (P < 0.001) with BMI and WC. The difference in BMI and WC between extreme quintiles of LTPA (Q1-Q5) was 2.1 kg/m2 (95% confidence interval (CI) 1.68; 2.49, P < 0.001) and 4.8 cm (CI 2.28; 7.25, P < 0.001), respectively. Low-intensity LTPA was inversely associated with BMI but not with WC, while moderate/vigorous LTPA showed an inverse relationship with BMI and WC. The hazard of general and abdominal obesity incidence decreased across quintiles of total and moderate/vigorous LTPA (P < 0.001 for both), whereas low-intensity LTPA was inversely associated with the incidence of general obesity (P < 0.001). LTPA was inversely associated with BMI, WC and incidence of general and abdominal obesity. The finding that low-intensity LTPA was inversely related to BMI and the incidence of obesity is of particular importance because this level of physical activity could be a feasible option for many older adults.

  18. Distribution of 14C-photosynthetate in the shoot of Vitis vinifera L. cv Cabernet Sauvignon: Pt. I

    International Nuclear Information System (INIS)

    Hunter, J.J.; Visser, J.H.

    1988-01-01

    The distribution of photosynthetates, originating in leaves of different parts of the shoot of Vitis vinifera L. cv Cabernet Sauvignon at berry set, pea size, veraison and ripeness stages, was investigated. Specific photosynthetic activity of the 14 CO 2 -treated leaves gradually decreased during the season. Photosynthetates were hoarded in the leaves at berry set, but were increasingly diverted to the bunches after that. The apical leaves displayed the highest photosynthesis. The leaves opposite and below the bunches accumulated very little photosynthetates, especially from veraison to ripeness. Redistribution of photosynthetates among the basal, middle and apical leaves was generally very restricted at all stages. Multidirectional distribution from the site of application of 14 CO 2 occurred at berry set stage, while from pea size to ripeness photosynthetates were mainly translocated basipetally. Highest accumulation in the bunches occurred at veraison, while the basal leaves were primarily used to nourish the bunch

  19. Distribution of 14C-photosynthetate in the shoot of Vitis vinifera L. cv Cabernet Sauvignon: Pt. II

    International Nuclear Information System (INIS)

    Hunter, J.J.; Visser, J.H.

    1988-01-01

    The effect of partial defoliation of Vitis vinifera L. cv Cabernet Sauvignon on the distribution of photosynthetates, originating in leaves in different positions on the shoot at berry set, pea size, veraison and ripeness stages, was investigated. Partial defoliation (33% and 66%) resulted in a higher apparent photosynthetic effectivity for all the remaining leaves on the shoot. The pattern of distribution of photosynthetates would seem to stay the same between the defoliation treatments. The control vines were found to carry excess foliage. Optimal photosynthetic activity of all the leaves on the vine was therefore not reached

  20. Quantitative Phosphoproteomics of Tomato Mounting a Hypersensitive Response Reveals a Swift Suppression of Photosynthetic Activity and a Differential Role for Hsp90 Isoforms

    DEFF Research Database (Denmark)

    Stulemeijer, Iris J E; Joosten, Matthieu H A J; Jensen, Ole N

    2009-01-01

    An important mechanism by which plants defend themselves against pathogens is the rapid execution of a hypersensitive response (HR). Tomato plants containing the Cf-4 resistance gene mount an HR that relies on the activation of phosphorylation cascades, when challenged with the Avr4 elicitor...... secreted by the pathogenic fungus Cladosporium fulvum. Phosphopeptides were isolated from tomato seedlings expressing both Cf-4 and Avr4 using titanium dioxide columns and LC-MS/MS analysis led to the identification of 50 phosphoproteins, most of which have not been described in tomato before......-dependent way during the very early stages of HR development. In addition, phosphopeptides originating from four Hsp90 isoforms exhibited altered abundances in Cf-4/Avr4 seedlings compared to control seedlings, suggesting that the isoforms of this chaperone protein have a different function in defense signaling...

  1. Active Case Finding Among Homeless People as a Means of Reducing the Incidence of Pulmonary Tuberculosis in General Population.

    Science.gov (United States)

    Romaszko, J; Siemaszko, A; Bodzioch, M; Buciński, A; Doboszyńska, A

    2016-01-01

    The incidence of tuberculosis (TB) declined more than two-fold, compared with the national average, in the northeastern region of Poland in the period of 2003-2012. During that time, four programs of active case finding of TB were conducted as part of which a total of 944 homeless individuals were examined and 21 cases of active TB were detected. The objective of the present study was to find out whether the observed beneficial epidemiological trend could be a result of those programs. We addressed the issue of how the active case finding programs in the homeless community affected the TB incidence in the general population using a modified crisscross SIS-type (Susceptible - Infected - Susceptible) model which describes the dynamics of TB spread between the homeless and non-homeless populations. The values calculated from our model proved highly congruent with the actual epidemiological data. Our analysis showed a significant decline in TB incidence within 1 year of completion of each active case finding program. The model shows that each identified and cured case in the homeless community reduced the number of new cases in the general population by 3-4 within 1 year and by up to 20 within 5 years.

  2. Effect of gamma radiation on photosynthetic metabolism of Chlorella pyrenoidosa studied by 14CO2 assimilation

    International Nuclear Information System (INIS)

    Martin Moreno, C.; Fernandez Gonzalez, J.

    1983-01-01

    The effect of five dose of gamma radiation (10, 100, 500, 1000 and 5000 Gy) on photosynthetic activity and metabolism of the primary products of photosynthesis has been studied, on Chlorella pyrenoidoBa cultures, by 14 C O 2 assimilation. The photosynthetic assimilation rate is remarkably depressed after irradiation at 500, 1000 and 5000 Gy dose, which also produce a significant change in radioactivity distribution pattern of primary compounds from photosynthesis. No significant effects have been observed on photosynthetic metabolism after irradiation at 10 and 100 Gy. (Author) 19 refs

  3. Photosynthetic system as a biological functional element

    International Nuclear Information System (INIS)

    Zakhidov, E.A.; Zakhidova, M.A.; Kasymdzhanov, M.A.; Kurbanov, S.S.; Nematov, Sh.K.; Khabibullaev, P.K.

    2005-01-01

    Photosynthetic apparatus of high plants and photosynthetic bacteria is essentially autonomic system in terms of genetics and structural -functional properties located in specific medium, a bio-membrane. Processes of light absorption and exciton migration in light harvesting antenna, separation and further transfer of charges in reaction centers have specific features, which may be used for application of these objects as key elements in construction of future biological functional elements. Progress in study and genetic modification of photosynthetic membranes achieved during the last decade opens great prospects in development biological functional elements and systems. The main characteristics of photosynthetic system for these purposes are: (i) energy conversion processes in the first light phase of the photosynthesis have very short periods, up to picoseconds, which indicates possibility of creation of ultrafast functional elements on their basis; (ii) characteristics sizes of photosynthetic units, 10-100 nm, and possibility to arrange regularly disposed elements in relevant membranes could be prospective point for creation of nano structures and on their basis relevant biologic functional elements; (iii) elements based on modified photosynthetic apparatus and bio-membranes might be efficiently created by methods of gene engineering and manipulation, that open huge opportunities for development of read biological functional systems. In the paper structural-functional properties and characteristics of high plants and purple photosynthetic bacteria, which may be useful for creation of future biological functional elements are considered. (author)

  4. Trends in Incidence of Disability in Activities of Daily Living in Chinese Older Adults: 1993-2006.

    Science.gov (United States)

    Liang, Yajun; Welmer, Anna-Karin; Wang, Rui; Song, Aiqin; Fratiglioni, Laura; Qiu, Chengxuan

    2017-02-01

    To investigate time trends in incidence of activity of daily living (ADL) disability of Chinese older adults and to explore factors potentially contributing to trends. Population-based prospective study using a multistage, randomized, cluster sampling process. Nine provinces of China. Three consecutive cohorts of people aged 60 and older from the China Health and Nutrition Survey: cohort 1993-2000 (n = 831), cohort 1997-2004 (n = 1,091), cohort 2000-2006 (n = 1,152). Disability in ADLs was defined as inability to perform at least one of five self-care activities (transferring, dressing, toileting, bathing, feeding). Data were analyzed using Cox and generalized estimating equation models. The incidence (per 1,000 person-years) of ADL disability decreased significantly from 35.3 in 1993-2000 and 28.9 in 1997-2004 to 24.3 in 2000-2006 in Chinese older adults (P trend < .001). The incidence of ADL disability decreased significantly in men and women, in young-old adults (aged 60-74), and in those living in rural areas (all P trend ≤ .02) after controlling for multiple potential influential factors. Of the five ADL items, decline in incidence of disability was significant in transferring (P trend < .001) and bathing (P trend = .002) and marginally significant in toileting (P trend = .06) but stable in dressing (P trend = .38) and feeding (P trend = .26). The incidence of ADL disability decreased from 1993 to 2006 in older adults in China, especially in transferring and bathing, independent of sociodemographic, lifestyle, and chronic health conditions. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

  5. Incidents of illicit trafficking and other unauthorized activities involving nuclear and other radioactive materials (1993-2005)

    International Nuclear Information System (INIS)

    2010-01-01

    The confirmed incidents of illicit trafficking and other unauthorized activities involving nuclear and other radioactive materials between 1993-2005 shows that, 27% involved nuclear materials, 62% radioactive materials,7% involved both nuclear and other radioactive materials while the remainder involved other radioactive and non radioactive materials.Also 80% of nuclear material which was recovered during the same period was not reported as stolen or lost.

  6. Photosynthetic rate, dry matter accumulation and yield inter-relationships jn genotypes of rice

    International Nuclear Information System (INIS)

    Devendra, R.; Udaya Kumar, M.; Krishna Sastry, K.S.

    1980-01-01

    The relationship between photosynthetic efficiency, dry matter accumulation and yield in five genotypes of paddy derived from a single cross between Jaya X Halubbalu was studied. Photosynthetic efficiency of younger leaves, on the main tiller was higher than in the older leaves. A significant positive correlation between RuDPcase activity and photosynthetic efficiency was observed in these genotypes. Also a similar positive correlation between dry matter production and photosynthetic efficiency during vegetative period but not during post-anthesis period was observed. Genotypes with high photosynthetic efficiency and also the genotypes with high LAD produced higher dry matter. A reduction in LAD or in photosynthetic efficiency during the post-anthesis period and thus a reduction in source capacity which occurred specially in late types resulted in a lesser ratio between productive and total tillers and also higher percent sterility. Differences in yield amongst the genotypes were not significant, since in the late types MR. 333 and MR. 335, the post-anthesis dry matter production was low due to lesser source capacity. But in the early types, though the total dry matter was less, the post-anthesis source capacity was high. The importance of post-anthesis leaf area of photo-synthetic efficiency in productivity in genotypes of rice is highlighted. (author)

  7. Physical Activity at 11 Years of Age and Incidence of Mental Health Problems in Adolescence: Prospective Study.

    Science.gov (United States)

    Hallal, Pedro C; Martínez-Mesa, Jeovany; Coll, Carolina V; Mielke, Grégore I; Mendes, Márcio A; Peixoto, Márcio B; Munhoz, Tiago N; Ramires, Virgilio V; Assunção, Maria Cecilia; Gonçalves, Helen; Menezes, Ana M

    2015-04-01

    To evaluate the longitudinal association between physical activity behavior at 11 years of age and the incidence of mental health problems from 11 to 15 years of age. Individuals born in the city of Pelotas, Brazil, in 1993 have been followed up since birth. At 11 and 15 years of age, mental health was assessed using the Strengths and Difficulties Questionnaire (SDQ). At 11 years of age, physical activity was assessed through a validated questionnaire. The continuous SDQ score at 15 years was used as the outcome variable. The main exposure was physical activity behavior at 11 years of age divided into 3 categories (0, 1-299, ≥ 300 min/wk). The incidence of mental health problems from 11 to 15 years was 13.6% (95% CI, 12.4-14.9). At 11 years, 35.2% of the adolescents achieved 300 min/wk of physical activity. In the unadjusted analysis, physical activity was inversely related to mental health problems (P = .04). After adjustment for confounders, the association was no longer significant in the whole sample but was still significant among boys. Physical activity appears to be inversely related to mental health problems in adolescence, but the magnitude of the association is weak to moderate.

  8. Dengue incidence in urban and rural Cambodia: results from population-based active fever surveillance, 2006-2008.

    Directory of Open Access Journals (Sweden)

    Sirenda Vong

    Full Text Available BACKGROUND: Dengue vaccines are now in late-stage development, and evaluation and robust estimates of dengue disease burden are needed to facilitate further development and introduction. In Cambodia, the national dengue case-definition only allows reporting of children less than 16 years of age, and little is known about dengue burden in rural areas and among older persons. To estimate the true burden of dengue in the largest province of Cambodia, Kampong Cham, we conducted community-based active dengue fever surveillance among the 0-to-19-year age group in rural villages and urban areas during 2006-2008. METHODS AND FINDINGS: Active surveillance for febrile illness was conducted in 32 villages and 10 urban areas by mothers trained to use digital thermometers combined with weekly home visits to identify persons with fever. An investigation team visited families with febrile persons to obtain informed consent for participation in the follow-up study, which included collection of personal data and blood specimens. Dengue-related febrile illness was defined using molecular and serological testing of paired acute and convalescent blood samples. Over the three years of surveillance, 6,121 fever episodes were identified with 736 laboratory-confirmed dengue virus (DENV infections for incidences of 13.4-57.8/1,000 person-seasons. Average incidence was highest among children less than 7 years of age (41.1/1,000 person-seasons and lowest among the 16-to-19-year age group (11.3/1,000 person-seasons. The distribution of dengue was highly focal, with incidence rates in villages and urban areas ranging from 1.5-211.5/1,000 person-seasons (median 36.5. During a DENV-3 outbreak in 2007, rural areas were affected more than urban areas (incidence 71 vs. 17/1,000 person-seasons, p<0.001. CONCLUSION: The large-scale active surveillance study for dengue fever in Cambodia found a higher disease incidence than reported to the national surveillance system, particularly

  9. Photosynthetic induction in broadleaved Fagus sylvatica and coniferous Picea abies cultivated under ambient and elevated CO2 concentrations

    Czech Academy of Sciences Publication Activity Database

    Košvancová, Martina; Urban, Otmar; Šprtová, Miroslava; Hrstka, M.; Kalina, J.; Tomášková, Ivana; Špunda, V.; Marek, Michal V.

    2009-01-01

    Roč. 177, - (2009), s. 123-130 ISSN 1212-2580 R&D Projects: GA MŠk OC08022; GA AV ČR IAA600870701 Institutional research plan: CEZ:AV0Z60870520 Keywords : gas exchange * photosynthetic limitations * photosynthetic down-regulation * Rubisco specific activity * stomatal conductance Subject RIV: ED - Physiology

  10. Hybrid system of semiconductor and photosynthetic protein

    Science.gov (United States)

    Kim, Younghye; Shin, Seon Ae; Lee, Jaehun; Yang, Ki Dong; Nam, Ki Tae

    2014-08-01

    Photosynthetic protein has the potential to be a new attractive material for solar energy absorption and conversion. The development of semiconductor/photosynthetic protein hybrids is an example of recent progress toward efficient, clean and nanostructured photoelectric systems. In the review, two biohybrid systems interacting through different communicating methods are addressed: (1) a photosynthetic protein immobilized semiconductor electrode operating via electron transfer and (2) a hybrid of semiconductor quantum dots and photosynthetic protein operating via energy transfer. The proper selection of materials and functional and structural modification of the components and optimal conjugation between them are the main issues discussed in the review. In conclusion, we propose the direction of future biohybrid systems for solar energy conversion systems, optical biosensors and photoelectric devices.

  11. Separation, identification and quantification of photosynthetic ...

    African Journals Online (AJOL)

    Thirty one photosynthetic pigments (chlorophylls, carotenoids and degradation products) from the seaweeds, Codium dwarkense, (Chlorophyta), , Laurencia obtusa , (Rhodophyta) and , Lobophora variegata, (Phaeophyta), were separated in a single-step procedure by reversed phase high-performance liquid ...

  12. Dengue Incidence in Urban and Rural Cambodia: Results from Population-Based Active Fever Surveillance, 2006–2008

    Science.gov (United States)

    Vong, Sirenda; Khieu, Virak; Glass, Olivier; Ly, Sowath; Duong, Veasna; Huy, Rekol; Ngan, Chantha; Wichmann, Ole; Letson, G. William; Margolis, Harold S.; Buchy, Philippe

    2010-01-01

    Background Dengue vaccines are now in late-stage development, and evaluation and robust estimates of dengue disease burden are needed to facilitate further development and introduction. In Cambodia, the national dengue case-definition only allows reporting of children less than 16 years of age, and little is known about dengue burden in rural areas and among older persons. To estimate the true burden of dengue in the largest province of Cambodia, Kampong Cham, we conducted community-based active dengue fever surveillance among the 0-to-19–year age group in rural villages and urban areas during 2006–2008. Methods and Findings Active surveillance for febrile illness was conducted in 32 villages and 10 urban areas by mothers trained to use digital thermometers combined with weekly home visits to identify persons with fever. An investigation team visited families with febrile persons to obtain informed consent for participation in the follow-up study, which included collection of personal data and blood specimens. Dengue-related febrile illness was defined using molecular and serological testing of paired acute and convalescent blood samples. Over the three years of surveillance, 6,121 fever episodes were identified with 736 laboratory-confirmed dengue virus (DENV) infections for incidences of 13.4–57.8/1,000 person-seasons. Average incidence was highest among children less than 7 years of age (41.1/1,000 person-seasons) and lowest among the 16-to-19–year age group (11.3/1,000 person-seasons). The distribution of dengue was highly focal, with incidence rates in villages and urban areas ranging from 1.5–211.5/1,000 person-seasons (median 36.5). During a DENV-3 outbreak in 2007, rural areas were affected more than urban areas (incidence 71 vs. 17/1,000 person-seasons, pdengue fever in Cambodia found a higher disease incidence than reported to the national surveillance system, particularly in preschool children and that disease incidence was high in both rural

  13. Dengue incidence in urban and rural Cambodia: results from population-based active fever surveillance, 2006-2008.

    Science.gov (United States)

    Vong, Sirenda; Khieu, Virak; Glass, Olivier; Ly, Sowath; Duong, Veasna; Huy, Rekol; Ngan, Chantha; Wichmann, Ole; Letson, G William; Margolis, Harold S; Buchy, Philippe

    2010-11-30

    Dengue vaccines are now in late-stage development, and evaluation and robust estimates of dengue disease burden are needed to facilitate further development and introduction. In Cambodia, the national dengue case-definition only allows reporting of children less than 16 years of age, and little is known about dengue burden in rural areas and among older persons. To estimate the true burden of dengue in the largest province of Cambodia, Kampong Cham, we conducted community-based active dengue fever surveillance among the 0-to-19-year age group in rural villages and urban areas during 2006-2008. Active surveillance for febrile illness was conducted in 32 villages and 10 urban areas by mothers trained to use digital thermometers combined with weekly home visits to identify persons with fever. An investigation team visited families with febrile persons to obtain informed consent for participation in the follow-up study, which included collection of personal data and blood specimens. Dengue-related febrile illness was defined using molecular and serological testing of paired acute and convalescent blood samples. Over the three years of surveillance, 6,121 fever episodes were identified with 736 laboratory-confirmed dengue virus (DENV) infections for incidences of 13.4-57.8/1,000 person-seasons. Average incidence was highest among children less than 7 years of age (41.1/1,000 person-seasons) and lowest among the 16-to-19-year age group (11.3/1,000 person-seasons). The distribution of dengue was highly focal, with incidence rates in villages and urban areas ranging from 1.5-211.5/1,000 person-seasons (median 36.5). During a DENV-3 outbreak in 2007, rural areas were affected more than urban areas (incidence 71 vs. 17/1,000 person-seasons, pdengue fever in Cambodia found a higher disease incidence than reported to the national surveillance system, particularly in preschool children and that disease incidence was high in both rural and urban areas. It also confirmed the

  14. Felonious or violent criminal activity that prohibits gun ownership among prior purchasers of handguns: incidence and risk factors.

    Science.gov (United States)

    Wright, Mona A; Wintemute, Garen J

    2010-10-01

    Federal law prohibits firearm possession by felons and certain others. Little is known about criminal activity resulting in new ineligibility to possess firearms among persons who have previously purchased them. Cohort study of handgun purchasers ages 21 to 49 in California in 1991, 2,761 with a non-prohibiting criminal history at the time of purchase and 4,495 with no prior criminal record, followed for up to 5 years. The primary outcome measures were the incidence and relative risk of conviction for a felony or violent misdemeanor resulting in ineligibility to possess firearms under (a) California law or (b) federal law. Secondary measures were the incidence and relative risk of conviction for murder, forcible rape, robbery, or aggravated assault; and of arrest for any crime. A new conviction for a felony or violent misdemeanor leading to ineligibility to possess firearms under federal law was identified for 0.9% of subjects with no prior criminal history and 4.5% of those with 1 or more prior convictions (hazard ratio, 5.1; 95% confidence interval, 3.3-7.7). Risk was related inversely to age and directly to the extent of the prior criminal history; incidence rates varied by a factor of 200 or more among subgroups based on these characteristics. Among legal purchasers of handguns, the incidence of new felonious and violent criminal activity resulting in ineligibility to possess firearms is low for those with no prior criminal history but is substantially higher for those with a prior criminal record and is affected by demographic characteristics.

  15. BOREAS TE-9 NSA Photosynthetic Capacity and Foliage Nitrogen Data

    Science.gov (United States)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Dang, Qinglai; Margolis, Hank; Coyea, Marie

    2000-01-01

    The Boreal Ecosystem-Atmospheric Study (BOREAS) TE-9 (Terrestrial Ecology) team collected several data sets related to chemical and photosynthetic properties of leaves in boreal forest tree species. This data set describes the spatial and temporal relationship between foliage nitrogen concentration and photosynthetic capacity in the canopies of black spruce, jack pine, and aspen located within the Northern Study Area (NSA). The data were collected from June to September 1994 and are useful for modeling the vertical distribution of carbon fixation for different forest types in the boreal forest. The data are available in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  16. Photosynthetic reaction center complexes from heliobacteria

    Science.gov (United States)

    Trost, J. T.; Vermaas, W. F. J.; Blankenship, R. E.

    1991-01-01

    Photosynthetic reaction centers are pigment-protein complexes that are responsible for the transduction of light energy into chemical energy. Considerable evidence indicates that photosynthetic organisms were present very early in the evolution of life on Earth. The goal of this project is to understand the early evolutionary development of photosynthesis by examining the properties of reaction centers isolated from certain contemporary organisms that appear to contain the simplest photosynthetic reaction centers. The major focus is on the family of newly discovered strictly anaerobic photosynthetic organisms that are grouped with the gram-positive phylum of bacteria. The properties of these reactions centers suggest that they may be the descendants of an ancestor that also gave rise to Photosystem 1 found in oxygen-evolving photosynthetic organisms. Photoactive reaction center-core antenna complexes were isolated from the photosynthetic bacteria, Heliobacillus mobilis and Heliobacterium gestii, by extraction of membranes with Deriphat 160C followed by differential centrifugation and sucrose density gradient centrifugation. Other aspects of this investigation are briefly discussed.

  17. Photosynthetic characteristics of Amaranthus tricolor, a C4 tropical leafy vegetable.

    Science.gov (United States)

    Lin, Z F; Ehleringer, J

    1983-06-01

    The gas exchange characteristics are reported for Amaranthus tricolor, a C4 vegetable amaranth of southeastern Asia. Maximum photosynthetic capacity was 48.3±1.0μmol CO2 m(-2)s(-1) and the temperature optimum was 35°C. The calculated intercellular CO2 concentration at this leaf temperature and an incident photon flux (400-700 mm) of 2 mmol m(-2)s(-1) averaged 208±14 μl l(-1), abnormally high for a C4 species. The photosynthetic rate, intercellular CO2 concentration, and leaf conductance all decreased with an increase in water vapor pressure deficit. However, the decrease in leaf conductance which resulted in a decrease in intercellular CO2 concentration accounted for only one fourth of the observed decrease in photosynthetic rate as water vapor pressure deficit was increased. Subsequent measurements indicated that the depence of net photosynthesis on intercellular CO2 concetration changed with water vapor pressure deficit.

  18. Flow of light energy in benthic photosynthetic microbial mats

    Energy Technology Data Exchange (ETDEWEB)

    Al-Najjar, Mohammad Ahmad A.

    2010-12-15

    The work in this thesis demonstrates the assessment of the energy budget inside microbial mat ecosystems, and the factors affecting light utilization efficiency. It presents the first balanced light energy budget for benthic microbial mat ecosystems, and shows how the budget and the spatial distribution of the local photosynthetic efficiencies within the euphotic zone depend on the absorbed irradiance (Jabs). The energy budget was dominated by heat dissipation on the expense of photosynthesis. The maximum efficiency of photosynthesis was at light limiting conditions When comparing three different marine benthic photosynthetic ecosystems (originated from Abu-Dhabi, Arctic, and Exmouth Gulf in Western Australia), differences in the efficiencies were calculated. The results demonstrated that the maximum efficiency depended on mat characteristics affecting light absorption and scattering; such as, photopigments ratio and distribution, and the structural organization of the photosynthetic organisms relative to other absorbing components of the ecosystem (i.e., EPS, mineral particles, detritus, etc.). The maximum efficiency decreased with increasing light penetration depth, and increased with increasing the accessory pigments (phycocyanin and fucoxanthin)/chlorophyll ratio. Spatial heterogeneity in photosynthetic efficiency, pigment distribution, as well as light acclimation in microbial mats originating from different geographical locations was investigated. We used a combined pigment imaging approach (variable chlorophyll fluorescence and hyperspectral imaging), and fingerprinting approach. For each mat, the photosynthetic activity was proportional to the local pigment concentration in the photic zone, but not for the deeper layers and between different mats. In each mat, yield of PSII and E1/2 (light acclimation) generally decreased in parallel with depth, but the gradients in both parameters varied greatly between samples. This mismatch between pigments concentration

  19. Photosynthetic acclimation to drought stress in Agave salmiana Otto ex Salm-Dyck seedlings is largely dependent on thermal dissipation and enhanced electron flux to photosystem I.

    Science.gov (United States)

    Campos, Huitziméngari; Trejo, Carlos; Peña-Valdivia, Cecilia B; García-Nava, Rodolfo; Conde-Martínez, F Víctor; Cruz-Ortega, Ma Del Rocío

    2014-10-01

    Agave salmiana Otto ex Salm-Dyck, a crassulacean acid metabolism plant that is adapted to water-limited environments, has great potential for bioenergy production. However, drought stress decreases the requirement for light energy, and if the amount of incident light exceeds energy consumption, the photosynthetic apparatus can be injured, thereby limiting plant growth. The objective of this study was to evaluate the effects of drought and re-watering on the photosynthetic efficiency of A. salmiana seedlings. The leaf relative water content and leaf water potential decreased to 39.6 % and -1.1 MPa, respectively, over 115 days of water withholding and recovered after re-watering. Drought caused a direct effect on photosystem II (PSII) photochemistry in light-acclimated leaves, as indicated by a decrease in the photosynthetic electron transport rate. Additionally, down-regulation of photochemical activity occurred mainly through the inactivation of PSII reaction centres and an increased thermal dissipation capacity of the leaves. Prompt fluorescence kinetics also showed a larger pool of terminal electron acceptors in photosystem I (PSI) as well as an increase in some JIP-test parameters compared to controls, reflecting an enhanced efficiency and specific fluxes for electron transport from the plastoquinone pool to the PSI terminal acceptors. All the above parameters showed similar levels after re-watering. These results suggest that the thermal dissipation of excess energy and the increased energy conservation from photons absorbed by PSII to the reduction of PSI end acceptors may be an important acclimation mechanism to protect the photosynthetic apparatus from over-excitation in Agave plants.

  20. Physical activity reduces the risk of incident type 2 diabetes in general and in abdominally lean and obese men and women: the EPIC-InterAct Study

    NARCIS (Netherlands)

    Ekelund, U.; Feskens, E.J.M.

    2012-01-01

    Aims/hypothesis We examined the independent and combined associations of physical activity and obesity with incident type 2 diabetes in men and women. Methods The InterAct case–cohort study consists of 12,403 incident type 2 diabetes cases and a randomly selected subcohort of 16,154 individuals,

  1. Experimental climate warming decreases photosynthetic efficiency of lichens in an arid South African ecosystem.

    Science.gov (United States)

    Maphangwa, Khumbudzo Walter; Musil, Charles F; Raitt, Lincoln; Zedda, Luciana

    2012-05-01

    Elevated temperatures and diminished precipitation amounts accompanying climate warming in arid ecosystems are expected to have adverse effects on the photosynthesis of lichen species sensitive to elevated temperature and/or water limitation. This premise was tested by artificially elevating temperatures (increase 2.1-3.8°C) and reducing the amounts of fog and dew precipitation (decrease 30.1-31.9%), in an approximation of future climate warming scenarios, using transparent hexagonal open-top warming chambers placed around natural populations of four lichen species (Xanthoparmelia austroafricana, X. hyporhytida , Xanthoparmelia. sp., Xanthomaculina hottentotta) at a dry inland site and two lichen species (Teloschistes capensis and Ramalina sp.) at a humid coastal site in the arid South African Succulent Karoo Biome. Effective photosynthetic quantum yields ([Formula: see text]) were measured hourly throughout the day at monthly intervals in pre-hydrated lichens present in the open-top warming chambers and in controls which comprised demarcated plots of equivalent open-top warming chamber dimensions constructed from 5-cm-diameter mesh steel fencing. The cumulative effects of the elevated temperatures and diminished precipitation amounts in the open-top warming chambers resulted in significant decreases in lichen [Formula: see text]. The decreases were more pronounced in lichens from the dry inland site (decline 34.1-46.1%) than in those from the humid coastal site (decline 11.3-13.7%), most frequent and prominent in lichens at both sites during the dry summer season, and generally of greatest magnitude at or after the solar noon in all seasons. Based on these results, we conclude that climate warming interacting with reduced precipitation will negatively affect carbon balances in endemic lichens by increasing desiccation damage and reducing photosynthetic activity time, leading to increased incidences of mortality.

  2. A double-edged sword: does highly active antiretroviral therapy contribute to syphilis incidence by impairing immunity to Treponema pallidum?

    Science.gov (United States)

    Rekart, Michael L; Ndifon, Wilfred; Brunham, Robert C; Dushoff, Jonathan; Park, Sang Woo; Rawat, Sanjana; Cameron, Caroline E

    2017-01-01

    Background and hypothesis Recently, the world has experienced a rapidly escalating outbreak of infectious syphilis primarily affecting men who have sex with men (MSM); many are taking highly active antiretroviral therapy (HAART) for HIV-1 infection. The prevailing hypothesis is that HAART availability and effectiveness have led to the perception among both individuals who are HIV-1 infected and those who are uninfected that HIV-1 transmission has become much less likely, and the effects of HIV-1 infection less deadly. This is expected to result in increased sexual risk-taking, especially unprotected anal intercourse, leading to more non-HIV-1 STDs, including gonorrhoea, chlamydia and syphilis. However, syphilis incidence has increased more rapidly than other STDs. We hypothesise that HAART downregulates the innate and acquired immune responses to Treponema pallidum and that this biological explanation plays an important role in the syphilis epidemic. Methods We performed a literature search and developed a mathematical model of HIV-1 and T. pallidum confection in a population with two risk groups with assortative mixing to explore the consequence on syphilis prevalence of HAART-induced changes in behaviour versus HAART-induced biological effects. Conclusions and implications Since rising syphilis incidence appears to have outpaced gonorrhoea and chlamydia, predominantly affecting HIV-1 positive MSM, behavioural factors alone may be insufficient to explain the unique, sharp increase in syphilis incidence. HAART agents have the potential to alter the innate and acquired immune responses in ways that may enhance susceptibility to T. pallidum. This raises the possibility that therapeutic and preventative HAART may inadvertently increase the incidence of syphilis, a situation that would have significant and global public health implications. We propose that additional studies investigating the interplay between HAART and enhanced T. pallidum susceptibility are needed

  3. Simulação estocástica da radiação fotossinteticamente ativa e da temperatura do ar por diferentes métodos Random simulation of photosynthetically active radiation and air temperature through different methods

    Directory of Open Access Journals (Sweden)

    Thomas Newton Martin

    2007-09-01

    Full Text Available O objetivo deste trabalho foi comparar três métodos para simulação de dados de radiação fotossinteticamente ativa e temperatura do ar, com o uso de parâmetros diários de 17 estações do Estado de São Paulo. A simulação foi realizada para o primeiro e o 16º dia de cada mês, conforme: a distribuição normal truncada a mais ou menos 1,96 de desvio-padrão; distribuição triangular assimétrica; e distribuição normal bivariada. As estimativas com os dados simulados foram comparadas com os respectivos parâmetros (obtidos com os dados observados, pelos testes de homogeneidade de variância F e Bartlett, teste t de comparação de médias, coeficiente de correlação de Pearson, índice de concordância de Willmott, índice de desempenho de Camargo, coeficiente angular e o teste de normalidade dos dados. A simulação pela distribuição normal bivariada é a mais adequada para representar as variáveis climáticas.The purpose of this work was to compare three methods for simulating data of photosynthetically active radiation and air temperature, using daily parameters of 17 stations of São Paulo State, Brazil. The simulation of those elements was carried out for de 1st and the 16th day of each month, through three cases: nonsymmetric triangular distribution; normal distribution truncated at 1.96 standard deviation; and bivaried normal distribution. The simulated data were evaluated through the tests of homogeneity of variance F and Bartlett, t test, agreement index of Willmott, angular coefficient of the straight line, the index of performance of Camargo and tack the normal distribution (uni-varied. The simulation using the bi-varied normal distribution is most appropriate for representing the climate variables.

  4. Activation energy of etching for CR-39 as a function of linear energy transfer of the incident particles

    CERN Document Server

    Awad, E M

    1999-01-01

    In this work, we have studied the effect of the radiation damage caused by the incident particles on the activation energy of etching for CR-39 samples. The damage produced by the incident particle is expressed in terms of the linear energy transfer (LET). CR-39 samples from American Acrylic were irradiated to three different LET particles. These are N (LET sub 2 sub 0 sub 0 = 20 KeV/mu m) as a light particle, Fe (LET sub 2 sub 0 sub 0 = 110 KeV/mu m) as a medium particle and fission fragments (ff) from a sup 2 sup 5 sup 2 Cf source as heavy particles. In general the bulk etch rate was calculated using the weight difference method and the track etch rate was determined using the track geometry at various temperatures (50-90 deg. C) and concentrations (4-9 N) of the NaOH etchant. The average activation energy E sub b related to the bulk etch rate v sub b was calculated from 1n v sub b vs. 1/T. The average activation energy E sub t related to the track etch rate v sub t was estimated from 1n v sub t vs. 1/T. It...

  5. Activity release from damaged fuel during the Paks-2 cleaning tank incident in the spent fuel storage pool

    International Nuclear Information System (INIS)

    Hozer, Zoltan; Szabo, Emese; Pinter, Tamas; Varju, Ilona Baracska; Bujtas, Tibor; Farkas, Gabor; Vajda, Nora

    2009-01-01

    During crud removal operations the integrity of 30 fuel assemblies was lost at high temperature at the unit No. 2 of the Paks NPP. Part of the fission products was released from the damaged fuel into the coolant of the spent fuel storage pool. The gaseous fission products escaped through the chimney from the reactor hall. The volatile and non-volatile materials remained mainly in the coolant and were collected on the filters of water purification system. The activity release from damaged fuel rods during the Paks-2 cleaning tank incident was estimated on the basis of coolant activity concentration measurements and chimney activity data. The typical release rate of noble gases, iodine and caesium was 1-3%. The release of non-volatile fission products and actinides was also detected.

  6. Activity release from damaged fuel during the Paks-2 cleaning tank incident in the spent fuel storage pool

    Energy Technology Data Exchange (ETDEWEB)

    Hozer, Zoltan, E-mail: hozer@aeki.kfki.h [Hungarian Academy of Sciences KFKI Atomic Energy Research Institute, H-1525 Budapest 114, P.O. Box 49 (Hungary); Szabo, Emese [Hungarian Academy of Sciences KFKI Atomic Energy Research Institute, H-1525 Budapest 114, P.O. Box 49 (Hungary); Pinter, Tamas; Varju, Ilona Baracska; Bujtas, Tibor; Farkas, Gabor [Nuclear Power Plant Paks, H-7031 Paks, P.O. Box 71 (Hungary); Vajda, Nora [Institute of Nuclear Techniques, Budapest University of Technology and Economics, H-1521 Budapest, Muegyetem rakpart 9 (Hungary)

    2009-07-01

    During crud removal operations the integrity of 30 fuel assemblies was lost at high temperature at the unit No. 2 of the Paks NPP. Part of the fission products was released from the damaged fuel into the coolant of the spent fuel storage pool. The gaseous fission products escaped through the chimney from the reactor hall. The volatile and non-volatile materials remained mainly in the coolant and were collected on the filters of water purification system. The activity release from damaged fuel rods during the Paks-2 cleaning tank incident was estimated on the basis of coolant activity concentration measurements and chimney activity data. The typical release rate of noble gases, iodine and caesium was 1-3%. The release of non-volatile fission products and actinides was also detected.

  7. Counting viruses and bacteria in photosynthetic microbial mats.

    Science.gov (United States)

    Carreira, Cátia; Staal, Marc; Middelboe, Mathias; Brussaard, Corina P D

    2015-03-01

    Viral abundances in benthic environments are the highest found in aquatic systems. Photosynthetic microbial mats represent benthic environments with high microbial activity and possibly high viral densities, yet viral abundances have not been examined in such systems. Existing extraction procedures typically used in benthic viral ecology were applied to the complex matrix of microbial mats but were found to inefficiently extract viruses. Here, we present a method for extraction and quantification of viruses from photosynthetic microbial mats using epifluorescence microscopy (EFM) and flow cytometry (FCM). A combination of EDTA addition, probe sonication, and enzyme treatment applied to a glutaraldehyde-fixed sample resulted in a substantially higher viral (5- to 33-fold) extraction efficiency and reduced background noise compared to previously published methods. Using this method, it was found that in general, intertidal photosynthetic microbial mats harbor very high viral abundances (2.8 × 10(10) ± 0.3 × 10(10) g(-1)) compared with benthic habitats (10(7) to 10(9) g(-1)). This procedure also showed 4.5- and 4-fold-increased efficacies of extraction of viruses and bacteria, respectively, from intertidal sediments, allowing a single method to be used for the microbial mat and underlying sediment. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  8. Assessing the effects of ultraviolet radiation on the photosynthetic potential in Archean marine environments

    Science.gov (United States)

    Avila-Alonso, Dailé; Baetens, Jan M.; Cardenas, Rolando; de Baets, Bernard

    2017-07-01

    In this work, the photosynthesis model presented by Avila et al. in 2013 is extended and more scenarios inhabited by ancient cyanobacteria are investigated to quantify the effects of ultraviolet (UV) radiation on their photosynthetic potential in marine environments of the Archean eon. We consider ferrous ions as blockers of UV during the Early Archean, while the absorption spectrum of chlorophyll a is used to quantify the fraction of photosynthetically active radiation absorbed by photosynthetic organisms. UV could have induced photoinhibition at the water surface, thereby strongly affecting the species with low light use efficiency. A higher photosynthetic potential in early marine environments was shown than in the Late Archean as a consequence of the attenuation of UVC and UVB by iron ions, which probably played an important role in the protection of ancient free-floating bacteria from high-intensity UV radiation. Photosynthetic organisms in Archean coastal and ocean environments were probably abundant in the first 5 and 25 m of the water column, respectively. However, species with a relatively high efficiency in the use of light could have inhabited ocean waters up to a depth of 200 m and show a Deep Chlorophyll Maximum near 60 m depth. We show that the electromagnetic radiation from the Sun, both UV and visible light, could have determined the vertical distribution of Archean marine photosynthetic organisms.

  9. Melanoma Incidence Rates in Active Duty Military Personnel Compared With a Population-Based Registry in the United States, 2000-2007

    Science.gov (United States)

    2014-03-01

    later in life, especially among those with fair skin pigmentation, light eye and hair color, and propensity to freckle.’*"^ Studies comparing melanoma ...Naval Health Research Center Melanoma Incidence Rates in Active-Duty Military Personnel Compared With A Population-based Registry in the United...San Diego, California 92106-3521 MILITARY MEDICINE, 179, 3:247, 2014 Melanoma Incidence Rates in Active Duty Military Personnel Compared With a

  10. Incidence of epileptiform EEG activity in children during mask induction of anaesthesia with brief administration of 8% sevoflurane.

    Directory of Open Access Journals (Sweden)

    Barbara Schultz

    Full Text Available BACKGROUND: A high incidence of epileptiform activity in the electroencephalogram (EEG was reported in children undergoing mask induction of anaesthesia with administration of high doses of sevoflurane for 5 minutes and longer. This study was performed to investigate whether reducing the time of exposure to a high inhaled sevoflurane concentration would affect the incidence of epileptiform EEG activity. It was hypothesized that no epileptiform activity would occur, when the inhaled sevoflurane concentration would be reduced from 8% to 4% immediately after the loss of consciousness. METHODOLOGY/PRINCIPAL FINDINGS: 70 children (age 7-96 months, ASA I-II, premedication with midazolam were anaesthetized with 8% sevoflurane in 100% oxygen via face mask. Immediately after loss of consciousness, the sevoflurane concentration was reduced to 4%. EEGs were recorded continuously and were later analyzed visually with regard to epileptiform EEG patterns. Sevoflurane at a concentration of 8% was given for 1.2 ± 0.4 min (mean ± SD. In 14 children (20% epileptiform EEG patterns without motor manifestations were observed (delta with spikes (DSP, rhythmic polyspikes (PSR, epileptiform discharges (PED in 10, 10, 4 children (14%, 14%, 6%. 38 children (54% had slow, rhythmic delta waves with high amplitudes (DS appearing on average before DSP. CONCLUSIONS/SIGNIFICANCE: The hypothesis that no epileptiform potentials would occur during induction of anaesthesia with a reduction of the inspired sevoflurane concentration from 8% to 4% directly after LOC was not proved. Even if 8% sevoflurane is administered only briefly for induction of anaesthesia, epileptiform EEG activity may be observed in children despite premedication with midazolam.

  11. Effects of INH, DNP, 2,4-D and CMU on the photosynthetic activity of barley and maize plants; Efecto de cuatro inhibidores metabolicos (INH, DNP, 2, 4-D y CMU) sobre la actividad fotosintetica de plantular de cebada (Hordeum vulgare L.) y Maiz (Zea mais L.)

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, J.; Prieto, M. P.

    1979-07-01

    Determinations of the rate of photosynthesis were made in barley and maize leaves treated with INH, DNP, 2,4-D or CMU. 1 ppm of the chemicals in nutritive solutions was absorbed by roots during 24 or 48 hours in both dark and light conditions. After this period, photosynthetic activity, compensation point and 14{sup C}O{sub 2} assimilation were determined. Results show that INH increases the rate of photosynthesis, DNP and 2,4-D do not alter it sensibly and CMU acts as a strong inhibitor of photosynthesis. Some possible applications for ths obtention of labelled compounds by biosynthesis are discussed. (Author) 87 refs.

  12. Mycorrhiza Symbiosis Increases the Surface for Sunlight Capture in Medicago truncatula for Better Photosynthetic Production

    Science.gov (United States)

    Adolfsson, Lisa; Keresztes, Áron; Uddling, Johan; Schoefs, Benoît; Spetea, Cornelia

    2015-01-01

    Arbuscular mycorrhizal (AM) fungi play a prominent role in plant nutrition by supplying mineral nutrients, particularly inorganic phosphate (Pi), and also constitute an important carbon sink. AM stimulates plant growth and development, but the underlying mechanisms are not well understood. In this study, Medicago truncatula plants were grown with Rhizophagus irregularis BEG141 inoculum (AM), mock inoculum (control) or with Pi fertilization. We hypothesized that AM stimulates plant growth through either modifications of leaf anatomy or photosynthetic activity per leaf area. We investigated whether these effects are shared with Pi fertilization, and also assessed the relationship between levels of AM colonization and these effects. We found that increased Pi supply by either mycorrhization or fertilization led to improved shoot growth associated with increased nitrogen uptake and carbon assimilation. Both mycorrhized and Pi-fertilized plants had more and longer branches with larger and thicker leaves than the control plants, resulting in an increased photosynthetically active area. AM-specific effects were earlier appearance of the first growth axes and increased number of chloroplasts per cell section, since they were not induced by Pi fertilization. Photosynthetic activity per leaf area remained the same regardless of type of treatment. In conclusion, the increase in growth of mycorrhized and Pi-fertilized Medicago truncatula plants is linked to an increase in the surface for sunlight capture, hence increasing their photosynthetic production, rather than to an increase in the photosynthetic activity per leaf area. PMID:25615871

  13. Mycorrhiza symbiosis increases the surface for sunlight capture in Medicago truncatula for better photosynthetic production.

    Directory of Open Access Journals (Sweden)

    Lisa Adolfsson

    Full Text Available Arbuscular mycorrhizal (AM fungi play a prominent role in plant nutrition by supplying mineral nutrients, particularly inorganic phosphate (Pi, and also constitute an important carbon sink. AM stimulates plant growth and development, but the underlying mechanisms are not well understood. In this study, Medicago truncatula plants were grown with Rhizophagus irregularis BEG141 inoculum (AM, mock inoculum (control or with P(i fertilization. We hypothesized that AM stimulates plant growth through either modifications of leaf anatomy or photosynthetic activity per leaf area. We investigated whether these effects are shared with P(i fertilization, and also assessed the relationship between levels of AM colonization and these effects. We found that increased P(i supply by either mycorrhization or fertilization led to improved shoot growth associated with increased nitrogen uptake and carbon assimilation. Both mycorrhized and P(i-fertilized plants had more and longer branches with larger and thicker leaves than the control plants, resulting in an increased photosynthetically active area. AM-specific effects were earlier appearance of the first growth axes and increased number of chloroplasts per cell section, since they were not induced by P(i fertilization. Photosynthetic activity per leaf area remained the same regardless of type of treatment. In conclusion, the increase in growth of mycorrhized and P(i-fertilized Medicago truncatula plants is linked to an increase in the surface for sunlight capture, hence increasing their photosynthetic production, rather than to an increase in the photosynthetic activity per leaf area.

  14. Photosynthetic complex stoichiometry dynamics in higher plants: environmental acclimation and photosynthetic flux control

    Directory of Open Access Journals (Sweden)

    Mark Aurel Schöttler

    2014-05-01

    Full Text Available The composition of the photosynthetic apparatus of higher plants is dynamically adjusted to long-term changes in environmental conditions such as growth light intensity and light quality, and to changing metabolic demands for ATP and NADPH imposed by stresses and leaf ageing. By changing photosynthetic complex stoichiometry, a long-term imbalance between the photosynthetic production of ATP and NADPH and their metabolic consumption is avoided, and cytotoxic side reactions are minimized. Otherwise, an excess capacity of the light reactions, relative to the demands of primary metabolism, could result in a disturbance of cellular redox homeostasis and an increased production of reactive oxygen species, leading to the destruction of the photosynthetic apparatus and the initiation of cell death programs. In this review, changes of the abundances of the different constituents of the photosynthetic apparatus in response to environmental conditions and during leaf ontogenesis are summarized. The contributions of the different photosynthetic complexes to photosynthetic flux control and the regulation of electron transport are discussed.

  15. Critical Incident Analysis Based Training: An Approach for Developing Active Racial/Cultural Awareness

    Science.gov (United States)

    Collins, Noah M.; Pieterse, Alex L.

    2007-01-01

    The authors discuss 2 perspectives on the Multicultural Counseling Competencies (D. W. Sue, P. Arredondo, & R. J. McDavis, 1992): fixed goal and process. Noting that the process has been underemphasized, they introduce active racial/cultural awareness as an operationalization of this perspective. Current training approaches are critiqued from this…

  16. Incidence of adverse drug reactions in human immune deficiency virus-positive patients using highly active antiretroviral therapy

    Directory of Open Access Journals (Sweden)

    B Akshaya Srikanth

    2012-01-01

    Full Text Available To estimate the incidence of adverse drug reactions (ADRs in Human immune deficiency virus (HIV patients on highly active antiretroviral therapy (HAART. To identify the risk factors associated with ADRs in HIV patients. To analyze reported ADRs based on various parameters like causality, severity, predictability, and preventability. Retrospective case-control study. An 18-month retrospective case-control study of 208 patients newly registered in ART center, RIMS hospital, Kadapa, were intensively monitored for ADRs to HAART. Predictability was calculated based on the history of previous exposure to drug. Multivariate logistic regressions were used to identify the risk factors for ADRs. Data were analyzed using the chi-square test for estimating the correlation between ADRs and different variables. All statistical calculations were performed using EpiInfo version 3.5.3. Monitoring of 208 retrospective patients by active Pharmacovigilance identified 105 ADRs that were identified in 71 patients. Skin rash and anemia were the most commonly observed ADRs. The organ system commonly affected by ADR was skin and appendages (31.57%. The ADRs that were moderate were 90.14% of cases. The incidence of ADRs (53.52% was higher with Zidovudine + Lamivudine + Nevirapine combination. CD4 cell count less than <250 cells/μl were 80.28%, male gender were observed to be the risk factors for ADRs. Our study finding showed that there is a need of active pharmaceutical care with intensive monitoring for ADRs in Indian HIV-positive patients who are illiterate, of male and female gender, with CD4 count ≤250 cells/mm 3 with comorbid conditions.

  17. The impact of FDA regulatory activities on incident dispensing of LABA-containing medication: 2005-2011.

    Science.gov (United States)

    Baker, Meghan A; Butler, Melissa G; Seymour, Sally; Zhang, Fang; Wu, Yute; Wu, Ann Chen; Levenson, Mark S; Wu, Pingsheng; Iyer, Aarthi; Toh, Sengwee; Iyasu, Solomon; Zhou, Esther H

    2017-09-14

    Evidence of safety issues associated with long-acting beta 2 -agonist (LABA) treatment has led to multiple regulatory activities by the U.S. Food and Drug Administration (FDA) on this class of medications. This study describes the impact of the regulatory activities on incident LABA-containing medication dispensing. A monthly rolling cohort of asthma patients who were eligible to initiate a LABA-containing product was created in the Mini-Sentinel Distributed Database between January 2005 and June 2011. Cohorts of individuals who initiated LABA were examined for the changes in the proportions of single-ingredient to fixed-dose inhaled corticosteroid (ICS)-LABA initiators, appropriate initiation of LABA-containing products, and use of controller medications. The impact of the 2005 and 2010 FDA regulatory activities associated with LABA-containing products was measured using interrupted time series with segmented regression. LABA-containing product initiation was declining prior to the 2005 regulatory activities and continued to decline over the study period, accompanied by increased initiation of fixed dose ICS-LABA among LABA initiators. While the 2010 regulatory activities had no immediate impact on the proportion of LABA initiation in patients with prior controller medication dispensing and/or poor asthma control, there was an increasing positive trend toward LABA initiation in the appropriate patient population after the regulatory activities. The 2005 and 2010 FDA regulatory activities likely had an impact on communicating the safety concerns of LABA products. However, the impact cannot be viewed independent of scientific publications, guidelines for asthma treatment and other regulatory activities.

  18. Suicide Incidence and Risk Factors in an Active Duty US Military Population

    Science.gov (United States)

    Ireland, Robert; Frost, Lucinda; Cottrell, Linda

    2012-01-01

    Objectives. The goal of this study was to investigate and identify risk factors for suicide among all active duty members of the US military during 2005 or 2007. Methods. The study used a cross-sectional design and included the entire active duty military population. Study sample sizes were 2 064 183 for 2005 and 1 981 810 for 2007. Logistic regression models were used. Results. Suicide rates for all services increased during this period. Mental health diagnoses, mental health visits, selective serotonin reuptake inhibitors (SSRIs), sleep prescriptions, reduction in rank, enlisted rank, and separation or divorce were associated with suicides. Deployments to Operation Enduring Freedom or Operation Iraqi Freedom were also associated with elevated odds ratios for all services in the 2007 population and for the Army in 2005. Conclusions. Additional research needs to address the increasing rates of suicide in active duty personnel. This should include careful evaluation of suicide prevention programs and the possible increase in risk associated with SSRIs and other mental health drugs, as well as the possible impact of shorter deployments, age, mental health diagnoses, and relationship problems. PMID:22390588

  19. Leisure-Time Physical Activity Reduces Total and Cardiovascular Mortality and Cardiovascular Disease Incidence in Older Adults.

    Science.gov (United States)

    Barengo, Noël C; Antikainen, Riitta; Borodulin, Katja; Harald, Kennet; Jousilahti, Pekka

    2017-03-01

    To determine whether leisure-time physical activity (LTPA) is independently associated with all-cause and cardiovascular mortality and with incidence of cardiovascular disease (CVD) and stroke in older adults. Population-based cohort study (median follow-up 11.8 years). Community, five Finnish provinces. Men and women aged 65 to 74 who participated in a baseline risk factor survey between 1997 and 2007 in Finland (N = 2,456). The study protocol included a self-administered questionnaire, health examination at the study site, and blood sample for laboratory analysis. LTPA was classified into three levels: low, moderate, high. Mortality data were obtained from the National Causes of Death Register and data on incident CVD (coronary heart disease, stroke) events from the National Hospital Discharge Register. Multifactorial-adjusted (age, area, study year, sex, smoking, body mass index, systolic blood pressure, serum cholesterol, education, marital status) risks of total mortality (moderate: hazard ratio (HR) = 0.61, 95% confidence interval (CI) = 0.50-0.74; high: HR = 0.47, 95% CI = 0.34-0.63, P for trend <.001), CVD mortality (moderate: HR = 0.46, 95% CI = 0.33-0.64; high: HR = 0.34, 95% CI = 0.20-0.59, P for trend <.001), and an incident CVD event (moderate HR = 0.69, 95% CI = 0.54-0.88; high: HR = 0.55, 95% CI = 0.38-0.79, P for trend <.001) were lower for those with moderate or high LTPA levels than for those with low LTPA levels. Further adjustment for self-reported inability to perform LTPA did not change the associations remarkably. Baseline LTPA reduces the risk of total and CVD mortality and incident CVD events in older adults independently of the major known CVD risk factors. The protective effect of LTPA is dose dependent. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

  20. Emerald zoyzia grass development regarding photosynthetically active radiation in different slopes Desenvolvimento da grama-esmeralda em relação à radiação fotossinteticamente ativa em diferentes declividades

    Directory of Open Access Journals (Sweden)

    Ruchele M. Coan

    2012-06-01

    Full Text Available With this study, the objective was to estimate the photosynthetically active radiation (PAR and to correlate it with the dry matter (MMSPA of the emerald zoysia (Zoysia japonica Steud. on surfaces with different expositions and slopes. The research was conducted at the Experimental Watershed of the Agricultural Engineering Department, School of Agriculture and Veterinary Sciences of São Paulo State University (FCAV/UNESP, Brazil, where the surfaces (H, 10 N, 30 N, 50 N, 10 S, 30 S, 50 S, 10 L, 30 L, 50 L, 10 O, 30 O and 50 O were used. To obtain the global solar radiation, it was installed an automated weather station where the PAR (dependent variable was obtained by the equation y = a + bx, and the global radiation was independent. To compare means of MMSPA, it was used the Tukey test at 5% probability, and to assess the relation PAR/MMSPA, the simple linear correlation coefficient. The result showed that the accumulation of these effects in the PAR increases with North exposure and decreases with the South, and exposure to 50N is most suitable for slopes, not having correlation between the PAR and the MMSPA for the surfaces evaluated for the study period.Com este trabalho, o objetivo foi estimar a radiação fotossinteticamente ativa (PAR e correlacioná-la com a massa de matéria seca (MMSPA da grama-esmeralda (Zoysia japonica Steud., em superfícies com diferentes exposições e declividades. A pesquisa foi desenvolvida na Bacia Hidrográfica Experimental do Departamento de Engenharia Rural, FCAV/UNESP, Brasil, onde foram utilizadas as superfícies (H; 10 N; 30 N; 50 N; 10 S; 30 S; 50 S; 10 L; 30 L; 50 L; 10 O; 30 O e 50 O. Para a obtenção da radiação solar global, foi instalada uma estação meteorológica automatizada, onde a PAR (variável dependente foi obtida por meio da equação y = a + bx, e a radiação global foi a independente. Para comparação de médias da MMSPA, utilizou-se o teste de Tukey, a 5% de probabilidade, e para

  1. BOREAS TE-09 Photosynthetic Capacity and Foliage Nitrogen Data

    Data.gov (United States)

    National Aeronautics and Space Administration — Contains TE-09 data on the response of photosynthetic capacity to foliage nitrogen concentration and photosynthetic capacity in the canopies of Norther Study Area...

  2. BOREAS TE-09 Photosynthetic Capacity and Foliage Nitrogen Data

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Contains TE-09 data on the response of photosynthetic capacity to foliage nitrogen concentration and photosynthetic capacity in the canopies of Norther...

  3. Ultrafast fluorescence of photosynthetic crystals and light-harvesting complexes

    NARCIS (Netherlands)

    Oort, van B.F.

    2008-01-01

    This thesis focuses on the study of photosynthetic pigment protein complexes using time resolved fluorescence techniques. Fluorescence spectroscopy often requires attaching fluorescent labels to the proteins under investigation. With photosynthetic proteins this is not necessary, because these

  4. Incidence of tuberculosis among HIV-infected patients receiving highly active antiretroviral therapy in Europe and North America

    NARCIS (Netherlands)

    Costagliola, D; Dabis, F; Monforte, AD; de Wolf, F; Egger, M; Fatkenheuer, G; Gill, J; Hogg, R; Justice, A; Ledergerber, B; Lundgren, J; May, M; Phillips, A; Reiss, P; Sabin, C; Staszewski, S; Sterne, J; Weller, H.H.; May, M; Beckthold, B; Yip, B; Dauer, B; Fusco, J; Grabar, S; Lanoy, E; Junghans, C; Lavignolle, V.; van Leth, F; Pereira, E; Pezzotti, P; Phillips, A; Sabin, C; Schmeisser, N; Billaud, E; Boue, F; Duval, J.; Duvivier, C; Enel, P; Fournier, S; Gasnault, J; Gaud, C; Gilquin, J; Grabar, S; Khuong, MA; Lang, JM; Mary-Krause, M; Matheron, S; Meyohas, MC; Pialoux, G; Poizot-Martin, I.; Pradier, C; Rouveix, E; Salmon-Ceron, D; Sobel, A; Tattevin, P; Tissot-Dupont, H; Yasdanpanah, Y; Aronica, E; Tirard-Fleury, V.; Tortay, I.; Abgrall, S; Guiguet, M; Leneman, H; Lievre, L; Potard, V.; Saidi, S; Matheron, S; Vilde, JL; Leport, C; Yeni, P; Bouvet, E; Gaudebout, C; Crickx, B; Picard-Dahan, C; Weiss, L; Tisne-Dessus, D; Sicard, D; Salmon, D; Auperin, A; Viard, JP; Roudiere, L; Delfraissy, JF; Goujard, C; Lesprit, P; Jung, C; Meyohas, MC; Meynard, JL; Picard, O; Desplanque, N; Cadranel, J; Mayaud, C; Rozenbaum, W; Bricaire, F; Katlama, C; Herson, S; Simon, A; Decazes, JM; Molina, JM; Clauvel, JP; Gerard, L; Widal, GHLF; Sellier, P; Diemer, M; Dupont, C; Berthe, H; Saiag, P; Mortier, L; Mortier, E; Chandemerle, C; de Truchis, P; Bentata, M; Honore, P; Tassi, S; Jeantils, V.; Mechali, D; Taverne, B; Laurichesse, H; Gourdon, F; Lucht, F; Fresard, A; Faller, JP; Eglinger, P; Bazin, C; Verdon, R; Peyramond, D; Boibieux, A; Touraine, JL; Livrozet, JM; Trepo, C; Cotte, L; Ravaux, I.; Delmont, JP; Moreau, J; Gastaut, JA; Soubeyrand, J; Retornaz, F; Blanc, PA; Allegre, T; Galinier, A; Ruiz, JM; Lepeu, G; Granet-Brunello, P; Pelissier, L; Esterni, JP; Nezri, M; Cohen-Valensi, R; Laffeuillade, A; Chadapaud, S; Reynes, J; May, T; Rabaud, C; Raffi, F; Pugliese, P; Michelet, C; Arvieux, C; Caron, F; Borsa-Lebas, F; Lang, JM; Fraisse, P; Massip, P; Cuzin, L; Arlet-Suau, E; Legrand, MFT; Yasdanpanah, Y; Sobesky, M; Pradinaud, R; Guyon, F; Contant, M; Montroni, M; Scalise, G; Braschi, MC; Aviano, AR; Tirelli, U; Cinelli, R; Pastore, G; Ladisa, N; Minafra, G; Suter, F; Arici, C; Chiodo, F; Colangeli, V.; Fiorini, C; Coronado, O; Carosi, G; Cadeo, GP; Torti, C; Minardi, C; Bertelli, D; Rizzardini, G; Melzi, S; Manconi, PE; Catanzaro, PP; Cosco, L; Scerbo, A; Vecchiet, J; D'Alessandro, M; Santoro, D; Pusterla, L; Carnevale, G; Citterio, P; Vigano, P; Mena, M; Ghinelli, F; Sighinolfi, L; Leoncini, F; Mazzotta, F; Pozzi, M; Lo Caputo, S; Angarano, G; Grisorio, B; Saracino, A; Ferrara, S; Grima, P; Tundo, P; Pagano, G; Cassola, G; Alessandrini, A; Piscopo, R; Toti, M; Chigiotti, S; Soscia, F; Tacconi, L; Orani, A; Perini, P; Scasso, A; Vincenti, A; Chiodera, F; Castelli, P; Scalzini, A; Palvarini, L; Moroni, M; Lazzarin, A; Cargnel, A; Vigevani, GM; Caggese, L; Monforte, AD; Repetto, D; Galli, A; Merli, S; Pastecchia, C; Moioli, MC; Esposito, R; Mussini, C; Abrescia, N; Chirianni, A; Izzo, CM; Piazza, M; De Marco, M; Viglietti, R; Manzillo, E; Nappa, S; Colomba, A; Abbadessa, V.; Prestileo, T; Mancuso, S; Ferrari, C; Pizzaferri, P; Filice, G; Minoli, L; Bruno, R; Novati, S; Baldelli, F; Tinca, M; Petrelli, E; Cioppi, A; Alberici, F; Ruggieri, A; Menichetti, F; Martinelli, C; De Stefano, C; La Gala, A; Ballardini, G; Rizzo, E; Magnani, G; Ursitti, MA; Arlotti, M; Ortolani, P; Cauda, R; Dianzani, F; Ippolito, G; Antinori, A; Antonucci, G; D'Elia, S; Narciso, P; Petrosillo, N; Vullo, V.; De Luca, A; Bacarelli, A; Zaccarelli, M; Acinapura, R; De Longis, P; Brandi, A; Trotta, MP; Noto, P; Lichtner, M; Capobianchi, MR; Carletti, F; Girardi, E; Pezzotti, P; Rezza, G; Mura, MS; Mannazzu, M; Caramello, P; Di Perri, G; Soranzo, ML; Orofino, GC; Arnaudo, I.; Bonasso, M; Grossi, PA; Basilico, C; Poggio, A; Bottari, G; Raise, E; Ebo, F; De Lalla, F; Tositti, G; Resta, F; Loso, K; Lepri, AC; Battegay, M; Bernasconi, E; Boni, J; Bucher, H; Burgisser, P; Cattacin, S; Cavassini, M; Dubs, R; Egger, M; Elzi, L; Erb, P; Fantelli, K; Fischer, M; Flepp, M; Fontana, A; Francioli, P; Furrer, H; Gorgievski, M; Hirschel, B; Kaiser, L; Kind, C; Klimkait, T; Lauper, U; Ledergerber, B; Opravil, M; Paccaud, F; Pantaleo, G; Perrin, L; Piffaretti, JC; Rickenbach, M; Rudin, C; Schmid, P; Schupbach, J; Speck, R; Telenti, A; Trkola, A; Vernazza, P; Weber, R; Yerly, S; Bronsveld, W; Hillebrand-Haverkort, ME; Prins, JM; Bos, JC; Schattenkerk, JKME; Geerlings, SE; Godfried, MH; Lange, JMA; van Leth, FC; Lowe, SH; van der Meer, JTM; Nellen, FJB; Pogany, K; van der Poll, T; Reiss, P; Ruys, TA; Sankatsing, S; Steingrover, R; van Twillert, G; van der Valk, M; van Vonderen, MGA; Vrouenraets, SME; van Vugt, M; Wit, FWMN; Kuijpers, TW; Pajkrt, D; Scherpbier, HJ; van Eeden, A; ten Veen, JH; van Dam, PS; Roos, JC; Brinkman, K; Frissen, PHJ; Weigel, HM; Mulder, JW; van Gorp, ECM; Meenhorst, PL; Mairuhu, ATA; Ziekenhuis, S; Veenstra, J; Danner, SA; van Agtmael, MA; Claessen, FAP; Perenboom, RM; Rijkeboer, A; van Vonderen, M; Richter, C; van der Berg, J; van Leusen, R; Vriesendorp, R; Jeurissen, FJF; Kauffmann, RH; Koger, ELW; Bravenboer, B; ten Napel, CHH; Kootstra, GJ; Sprenger, HG; Miesen, WMAJ; Doedens, Rienus; Scholvinck, EH; ten Kate, RW; van Houte, DPF; Polee, M; Kroon, FP; Broek, van den; van Dissel, JT; Schippers, EF; Schreij, G; de Geest, SV; Verbon, A; Koopmans, PP; Keuter, M; Post, F; van der Ven, AJAM; van der Ende, Marchina E.; Gyssens, IC; van der Feltz, M; den Hollander, JG; de Marie, S; Nouwen, JL; Rijnders, BJA; de Vries, TEMS; Driessen, G; de Groot, R; Hartwig, N; Juttmann, J.; van de Heul, C; van Kasteren, MEE; Schneider, MME; Bonten, MJM; Borleffs, JCC; Ellerbroek, PM; Hoepelman, IM; Jaspers, CAJJ; Schouten, M.C.; Schurink, CAM; Geelen, SPM; Wolfs, TFW; Blok, WL; Tanis, AA; Groeneveld, PHP; Back, NKT; Bakker, MEG; Berkhout, B; Jurriaans, S; Cuijpers, T; Rietra, PJGM; Roozendaal, KJ; Pauw, W; van Zanten, AP; von Blomberg, BME; Savelkoul, P; Swanink, CMA; Franck, PFH; Lampe, AS; Hendriks, R; Schirm, J; Veenendaal, D; Storm, H; Weel, J; van Zeijl, H; Kroes, ACM; Claas, HCJ; Bruggeman, CAMVA; Goossens, VJ; Galama, JMD; Melchers, WJG; Poort, YAG; Doornum, GJJ; Niesters, MG; Osterhaus, ADME; Schutten, M; Buiting, AGM; Swaans, CAM; Boucher, CAB; Boel, E; Jansz, AF; Losso, M; Duran, A; Vetter, N; Karpov, A.; Vassilenko, A; Clumeck, N; De Wit, S; Poll, B; Colebunders, R; Machala, L; Rozsypal, H; Sedlacek, D; Nielsen, J; Lundgren, J; Benfield, T; Kirk, O; Gerstoft, J; Katzenstein, T; Hansen, ABE; Skinhoj, P; Pedersen, C; Zilmer, K; Katlama, C; Girard, PM; Viard, JP; Saint-Marc, T; Vanhems, P; Pradier, C; Dietrich, M; Manegold, C; van Lunzen, J; Stellbrink, HJ; Staszewski, S; Bickel, M; Goebel, FD; Fatkenheuer, G; Rockstroh, J; Schmidt, R; Kosmidis, J; Gargalianos, P; Sambatakou, H; Perdios, J; Panos, G; Filandras, A; Karabatsaki, E; Banhegyi, D; Mulcahy, F; Yust, I.; Turner, D; Burke, M; Pollack, S; Hassoun, G; Sthoeger, Z; Maayan, S; Chiesi, A; Esposito, R; Borghi, R; Arici, C; Pristera, R; Mazzotta, F; Gabbuti, A; Lichtner, M; Chirianni, A; Montesarchio, E; Iacomi, F; Lazzarin, A; Finazzi, R; Viksna, L; Chaplinskas, S; Hemmer, R; Staub, T; Reiss, P; Bruun, J; Maeland, A; Ormaasen, V.; Knysz, B; Gasiorowski, J; Horban, A; Prokopowicz, D; Wiercinska-Drapalo, A; Boron-Kaczmarska, A; Pynka, M; Beniowski, M; Mularska, E; Trocha, H; Antunes, F; Valadas, E; Mansinho, K; Matez, F; Duiculescu, D; Babes, V.; Streinu-Cercel, A; Vinogradova, E; Rakhmanova, A; Jevtovic, D; Mokras, M; Stanekova, D; Gonzalez-Lahoz, J; Sanchez-Conde, M; Garcia-Benayas, T; Martin-Carbonero, L; Soriano, Joan B.; Clotet, B; Jou, A; Conejero, J; Tural, C; Gatell, JM; Miro, JM; Blaxhult, A; Karlsson, A; Pehrson, P; Ledergerber, B; Weber, R; Francioli, P; Telenti, A; Hirschel, B; Soravia-Dunand, V.; Furrer, H; Kravchenko, E; Chentsova, N; Barton, S; Johnson, AM; Mercey, D; Phillips, A; Johnson, MA; Mocroft, A; Murphy, M; Weber, J; Scullard, G; Fisher, M; Brettle, R; Loveday, C; Clotet, B; Antunes, F; Blaxhult, A; Clumeck, N; Gatell, J; Horban, A; Johnson, A; Katlama, C; Ledergerber, B; Loveday, C; Phillips, A; Reiss, P; Vella, S; Gjorup, N; Kirk, O; Friis-Moeller, N; Mocroft, A; Cozzi-Lepri, A; Bannister, W; Mollerup, D; Podlevkareva, D; Olsen, CH; Kjaer, J; Raffanti, S; Dieterch, D; Justice, A; Becker, S; Scarsella, A; Fusco, G; Most, B; Balu, R; Rana, R; Beckerman, R; Ising, T; Fusco, J; Irek, R; Johnson, B; Hirani, A; DeJesus, E; Pierone, G; Lackey, P; Irek, C; Johnson, A; Burdick, J; Leon, S; Arch, J; Staszewski, S; Helm, EB; Carlebach, A; Muller, A; Haberl, A; Nisius, G; Lennemann, T; Rottmann, C; Muller, A; Haberl, A; Nisius, G; Lennemann, T; Rottmann, C; Wolf, T; Stephan, C; Bickel, M; Mosch, M; Gute, P; Locher, L; Lutz, T; Klauke, S; Knecht, G; Doerr, HW; Sturmer, M; Dauer, B; von Hentig, N; Jennings, B; Beylot, J; Chene, G; Dabis, F; Dupon, M; Longy-Boursier, M; Pellegrin, JL; Ragnaud, JM; Salamon, R; Dabis, F; Chene, G; Thiebaut, R; Lewden, C; Lawson-Ayayi, S; Dupon, M; Mercie, P; Moreau, JF; Moriat, P; Pellegrin, JL; Ragnaud, JM; Bernard, N; Lacoste, D; Malvy, D; Neau, D; Blaizeau, MJ; Decoin, M; Delveaux, S; Hannapier, C; Labarrere, S; Lavignolle-Aurillac, V.; Uwamaliya-Nziyumvira, B; Palmer, G; Touchard, D; Balestre, E; Alioum, A; Jacqmin-Gadda, H; Thiebaut, R; Beylot, J; Morlat, P; Bernard, N; Bonarek, M; Bonnet, F; Coadou, B; Gellie, P; Lacoste, D; Nouts, C; Dupon, M; Bocquentin, F; Dutronc, H; Lafarie, S; Longy-Boursier, M; Mercie, P; Aslan, A; Malvy, D; Pistonne, T; Thibaut, P; Vatan, R; Ragnaud, JM; Chambon, D; De La Taille, C; Cazorla, C; Neau, D; Ocho, A; Pellegrin, JL; Castera, L; Fleury, H; Lafon, ME; Masquelier, B; Pellegrin, E.; Breilh, D; Moreau, JF; Blanco, P; Loste, P; Caunegre, L; Bonnal, F; Farbos, S; Ferrand, M; Ceccaldi, J; Tchamgoue, S; De Witte, S; Buy, E; Alexander, C; Barrios, R; Braitstein, P; Brumme, Z; Chan, K; Cote, H; Gataric, N; Geller, J; Guillemi, S; Harrigan, K.; Harris, M; Hogg, R; Joy, R; Levy, A; Montaner, J; Montessori, V.; Palepu, A; Phillips, E; Phillips, P; Press, N; Tyndall, M; Wood, E; Yip, B; Ballinger, J; Bhagani, S; Breen, R; Byrne, P; Carroll, A; Cropley, Mark; Cuthbertson, Z; Drinkwater, T; Fernandez, T; Geretti, AM; Murphy, G; Ivens, D; Johnson, M; Kinloch-de Loes, S; Lipman, M; Madge, S; Prinz, B; Bell, DR; Shah, S; Swaden, L; Tyrer, M; Youle, M; Chaloner, C; Gumley, H; Holloway, J; Puradiredja, D; Sweeney, J; Tsintas, R; Bannister, W; Bansi, L; Cozzi-Lepri, A; Fox, Z; Lampe, F; Mocroft, A; Phillips, A; Sabin, C; Smith, C; Amoah, E; Clewley, G; Dann, L; Gregory, B; Jani, I.; Janossy, G; Kahan, M; Loveday, C; Thomas, M; Gill, MJ; Read, R; Fatkenheuer, G; Rockstroh, J; Schmeisser, V.; Voigt, K; Wasmuth, JC; Wohrmann, A

    2005-01-01

    Background. We obtained estimates of the incidence of tuberculosis (TB) among patients receiving HAART and identified determinants of the incidence. Methods. We analyzed the incidence of TB during the first 3 years after initiation of HAART among 17,142 treatment-naive, AIDS- free persons starting

  5. Growth, Photosynthetic Efficiency, Rate of Transpiration, Lodging ...

    African Journals Online (AJOL)

    Growth, Photosynthetic Efficiency, Rate of Transpiration, Lodging, and Grain Yield of Tef ( Eragrostis Tef (Zucc) Trotter ) as Influenced by Stage and Rate of Paclobutrazol ... Paclobutrazol treatment had reduced plant height and total leaf area there by reduced excessive vegetative growth and lodging percentage.

  6. Photosynthetic carbon metabolism in freshwater phytoplankton

    International Nuclear Information System (INIS)

    Groeger, A.W.

    1986-01-01

    Photosynthetic carbon metabolism of natural assemblages of freshwater phytoplankton was measured by following the flow of inorganic 14 C into the photosynthetic end products polysaccharide protein, lipid, and soluble metabolites. Data were collected from a wide range of physical, chemical, and trophic conditions in six southern United States reservoirs, with the primary environmental variables of interest being light intensity and nutrient supply. Polysaccharide and protein were consistently the primary products of photosynthetic carbon metabolism, comprising an average of 70% of the total carbon fixation over a wide range of light intensities. Polysaccharide was quantitatively more important at higher light intensities, and protein at lower light intensities, as light intensity varied both with depth within the water column and over diurnal cycles. Polysaccharide synthesis was more variable over the diurnal period than was protein synthesis. Phytoplankton in the downlake epilimnion of Normandy Lake, a central Tennessee reservoir, responded to summer nitrogen (N) deficiency by increasing relative rates of lipid synthesis from 10-15% to 20-25% of the total photosynthetic carbon fixation. Phytoplankton in more nitrogen-sufficient areas of the reservoir maintained lower rates of lipid synthesis throughout the summer. These results document the occurrence in nature of a relationship between N-deficiency and increased lipid synthesis previously observed only in laboratory algal culture studies

  7. Difference in photosynthetic performance among three peach ...

    African Journals Online (AJOL)

    The effects of low photosynthetic photon flux density (PPFD) on greenhouse grown peach trees ('Qingfeng': Prunus persica L. Batsch, 'NJN76': Prunus persica L. Batsch and 'Maixiang': P. persica var. nectarine) were investigated. Difference in photosynthesis rate (Pn) and stoma morphology among cultivars were studied.

  8. Photosynthetic differences between Microcystis aeruginosa and ...

    African Journals Online (AJOL)

    In 1991 Oscillatoria simplicissima replaced Microcystis aeruginosa in the Vaal River, South Africa. This study explored the reason for this succession by looking at the photosynthetic performance of these two cyanoprokaryotes at different temperatures, light intensities and N:P ratios. Microcystis aeruginosa showed higher ...

  9. The evolution of photosynthetic capacity and the antioxidant enzymatic system during acclimatization of micropropagated Calathea plants.

    Science.gov (United States)

    Van Huylenbroeck JM; Piqueras; Debergh

    2000-06-12

    The effects of an increased PPFD on photosynthesis, the functioning of the photosynthetic apparatus and the response of the antioxidant enzymatic system were studied during the ex vitro establishment of micropropagated Calathea 'Maui Queen' plantlets. Measured chlorophyll and carotenoids contents in ex vitro formed leaves were almost three times higher compared to the in vitro formed ones. At the end of the acclimatization, an inverse relation between PPFD and the chlorophyll (a+b)/carotenoids ratio was observed. During the first days after transplantation Calathea plants are not photosynthetically active, as is illustrated by the photosynthetic light response curves. With the appearance of new leaves, higher photosynthetic capacities were observed and light saturation point increased (days 17 and 25). Also the maximal photosynthetic efficiency enlarged as shown by the increased initial slope of the curves. F(v)/F(m) decreased directly after transplantation of the micropropagated plantlets, afterwards a recovery was observed, but highest F(v)/F(m) values were observed in low light (LL) plants. The photochemical quenching coefficient increased gradually during the first two weeks of the acclimatization. In high light (HL) plants, q(P) decreased directly after transfer, while this was not observed in LL and medium light (ML). During the acclimatization period to increasing light intensities significant changes in the activity of the antioxidant enzymatic system were observed. A decrease in superoxide dismutase (SOD) activity was measured during the first half of the acclimatization period followed by a recovery in ML and HL plants by day 35. Dehydroascorbate reductase (DHAR) activity decreased during acclimatization. At the end of the experimental period the lowest levels were measured in ML plants. Catalase (CAT) activity increased significantly during the first two weeks after transfer, a clear inverse relationship to PPFD was detected. The relation between the

  10. Incidence of transfusion reactions: a multi-center study utilizing systematic active surveillance and expert adjudication

    Science.gov (United States)

    Hendrickson, Jeanne E.; Roubinian, Nareg H.; Chowdhury, Dhuly; Brambilla, Don; Murphy, Edward L.; Wu, Yanyun; Ness, Paul M.; Gehrie, Eric A.; Snyder, Edward L.; Hauser, R. George; Gottschall, Jerome L.; Kleinman, Steve; Kakaiya, Ram; Strauss, Ronald G.

    2017-01-01

    Background Prevalence estimates of serious hazards of transfusion vary widely. We hypothesized that the current reporting infrastructure in the United States fails to capture many transfusion reactions, and undertook a multi-center study utilizing active surveillance, data review, and adjudication to test this hypothesis. Study Design and Methods A retrospective record review was completed for a random sample of 17% of all inpatient transfusion episodes over 6 months at 4 academic tertiary care hospitals, with an episode defined as all blood products released to a patient in 6 hours. Data were recorded by trained clinical research nurses, and serious reactions were adjudicated by a panel of transfusion medicine experts. Results Of 4857 transfusion episodes investigated, 1.1% were associated with a serious reaction. Transfusion associated circulatory overload (TACO) was the most frequent serious reaction noted, being identified in 1% of transfusion episodes. Despite clinical notes describing a potential transfusion association in 59% of these cases, only 5.1% were reported to the transfusion service. Suspected transfusion related acute lung injury (TRALI/possible TRALI), anaphylactic, and hypotensive reactions were noted in 0.08%, 0.02%, and 0.02% of transfusion episodes. Minor reactions, including febrile non-hemolytic and allergic, were noted in 0.62% and 0.29% of transfusion episodes, with 30–50% reported to the transfusion service. Conclusion Underreporting of cardiopulmonary transfusion reactions is striking among academic, tertiary care hospitals. Complete and accurate reporting is essential to identify, define, establish pathogenesis, and mitigate/treat transfusion reactions. A better understanding of the failure to report may improve the accuracy of passive reporting systems. PMID:27460200

  11. UV-B photoreceptor-mediated protection of the photosynthetic machinery in Chlamydomonas reinhardtii

    Science.gov (United States)

    Allorent, Guillaume; Lefebvre-Legendre, Linnka; Chappuis, Richard; Kuntz, Marcel; Truong, Thuy B.; Niyogi, Krishna K.; Goldschmidt-Clermont, Michel

    2016-01-01

    Life on earth is dependent on the photosynthetic conversion of light energy into chemical energy. However, absorption of excess sunlight can damage the photosynthetic machinery and limit photosynthetic activity, thereby affecting growth and productivity. Photosynthetic light harvesting can be down-regulated by nonphotochemical quenching (NPQ). A major component of NPQ is qE (energy-dependent nonphotochemical quenching), which allows dissipation of light energy as heat. Photodamage peaks in the UV-B part of the spectrum, but whether and how UV-B induces qE are unknown. Plants are responsive to UV-B via the UVR8 photoreceptor. Here, we report in the green alga Chlamydomonas reinhardtii that UVR8 induces accumulation of specific members of the light-harvesting complex (LHC) superfamily that contribute to qE, in particular LHC Stress-Related 1 (LHCSR1) and Photosystem II Subunit S (PSBS). The capacity for qE is strongly induced by UV-B, although the patterns of qE-related proteins accumulating in response to UV-B or to high light are clearly different. The competence for qE induced by acclimation to UV-B markedly contributes to photoprotection upon subsequent exposure to high light. Our study reveals an anterograde link between photoreceptor-mediated signaling in the nucleocytosolic compartment and the photoprotective regulation of photosynthetic activity in the chloroplast. PMID:27930292

  12. Incidence of Norovirus-Associated Medical Encounters among Active Duty United States Military Personnel and Their Dependents.

    Directory of Open Access Journals (Sweden)

    Brian Rha

    Full Text Available Norovirus is a leading cause of gastroenteritis episodes and outbreaks in US military deployments, but estimates of endemic disease burden among military personnel in garrison are lacking.Diagnostic codes from gastroenteritis-associated medical encounters of active duty military personnel and their beneficiaries from July 1998-June 2011 were obtained from the Armed Forces Health Surveillance Center. Using time-series regression models, cause-unspecified encounters were modeled as a function of encounters for specific enteropathogens. Model residuals (representing unexplained encounters were used to estimate norovirus-attributable medical encounters. Incidence rates were calculated using population data for both active duty and beneficiary populations.The estimated annual mean rate of norovirus-associated medically-attended visits among active duty personnel and their beneficiaries was 292 (95% CI: 258 to 326 and 93 (95% CI: 80 to 105 encounters per 10,000 persons, respectively. Rates were highest among beneficiaries <5 years of age with a median annual rate of 435 (range: 318 to 646 encounters per 10,000 children. Norovirus was estimated to cause 31% and 27% of all-cause gastroenteritis encounters in the active duty and beneficiary populations, respectively, with over 60% occurring between November and April. There was no evidence of any lag effect where norovirus disease occurred in one population before the other, or in one beneficiary age group before the others.Norovirus is a major cause of medically-attended gastroenteritis among non-deployed US military active duty members as well as in their beneficiaries.

  13. Radiative Energy Budgets of Phototrophic Surface-Associated Microbial Communities and their Photosynthetic Efficiency Under Diffuse and Collimated Light.

    Science.gov (United States)

    Lichtenberg, Mads; Brodersen, Kasper E; Kühl, Michael

    2017-01-01

    We investigated the radiative energy budgets of a heterogeneous photosynthetic coral reef sediment and a compact uniform cyanobacterial biofilm on top of coastal sediment. By combining electrochemical, thermocouple and fiber-optic microsensor measurements of O 2 , temperature and light, we could calculate the proportion of the absorbed light energy that was either dissipated as heat or conserved by photosynthesis. We show, across a range of different incident light regimes, that such radiative energy budgets are highly dominated by heat dissipation constituting up to 99.5% of the absorbed light energy. Highest photosynthetic energy conservation efficiency was found in the coral sediment under low light conditions and amounted to 18.1% of the absorbed light energy. Additionally, the effect of light directionality, i.e., diffuse or collimated light, on energy conversion efficiency was tested on the two surface-associated systems. The effects of light directionality on the radiative energy budgets of these phototrophic communities were not unanimous but, resulted in local spatial differences in heat-transfer, gross photosynthesis, and light distribution. The light acclimation index, E k , i.e., the irradiance at the onset of saturation of photosynthesis, was >2 times higher in the coral sediment compared to the biofilm and changed the pattern of photosynthetic energy conservation under light-limiting conditions. At moderate to high incident irradiances, the photosynthetic conservation of absorbed energy was highest in collimated light; a tendency that changed in the biofilm under sub-saturating incident irradiances, where higher photosynthetic efficiencies were observed under diffuse light. The aim was to investigate how the physical structure and light propagation affected energy budgets and light utilization efficiencies in loosely organized vs. compact phototrophic sediment under diffuse and collimated light. Our results suggest that the optical properties and the

  14. Spatial Analyses of the Relation between Rodent’s Active Burrows and Incidence of Zoonotic Cutaneous Leishmaniasis in Golestan Province, Northeastern of Iran

    Directory of Open Access Journals (Sweden)

    Aioub Sofizadeh

    2016-10-01

    Full Text Available AbstractBackground: Zoonotic cutaneous leishmaniasis (ZCL is one of the most important vector-borne diseases in Iran. Wild Rodents play as a reservoir. The main aim of this study was to determine spatial analyses of the relationship between rodent’s active burrows and Incidence of ZCL in Golestan Province, north east of Iran. Methods: The cross-sectional study was conducted in 59 rural districts in Golestan Province. Spatial distribution of rodent’s active burrows, human cases of ZCL and Incidence of disease were collected, using Geographical Infor­mation Systems (GIS. The relationship of them were analyzed by Sperman test, SPSS software version No.13.Results: The most number of rodents’ active burrows, human positive cases (100 persons and high Incidence of disease (35/1000 were observed in Korand rural district of Gonbad-e Kavoos County. There was significant corre­lation between the number of rodents active burrows with Incidence rate of disease (0.470, P< 0.001 as well as the number of cases in each districts (0.465, P< 0.001, There is high correlation between higher Incidence rate and hu­man positive cases in districts with number of rodents’ active burrows.  Conclusion: Vicinity of wild rodents’ burrows to villages plays an important role in transmission of ZCL to humans.

  15. Physical activity and 10-year incidence of self-reported vertebral fractures in Japanese women: the Japan Public Health Center-based Prospective Study.

    Science.gov (United States)

    Nakamura, K; Kitamura, K; Inoue, M; Sawada, N; Tsugane, S

    2014-11-01

    This study assessed the effects of physical activity on a 10-year incidence of self-reported vertebral fractures in adult women of a large Japanese cohort. Medium levels of strenuous activity and long-duration sedentary activity were associated with a lower incidence of vertebral fractures; association patterns appear to be different from hip fractures. Physical activity helps prevent hip fracture, but little is known about the longitudinal association between physical activity and vertebral fractures. The purpose of this study was to evaluate the effects of physical activity on the 10-year incidence of symptomatic vertebral fractures using data from the Japan Public Health Center-based Prospective Study. Baseline studies were conducted in 1993-1994, and the follow-up study was conducted 10 years later. We analyzed 23,757 women aged 40-69 years. At baseline, physical activity was assessed as a predictor by using a questionnaire. Subjects were asked to report vertebral fractures that occurred during the 10-year follow-up period. Relative risks (RRs) adjusted for confounders were estimated by multiple logistic regression analysis. The 10-year cumulative incidence of vertebral fractures was 0.67%. Those who engaged in strenuous physical activity of <1 h/day had a significantly lower incidence of vertebral fractures than those who did not engage in such activity (RR = 0.52, 95% CI 0.28-0.97), while those engaged in such activity ≥1 h/day did not (RR = 0.82, 95% CI 0.58-1.14). Long-duration sedentary activity was associated with a low incidence of vertebral fractures (P for trend = 0.0002), but the frequencies of sports activities and metabolic equivalents were not (P for trend = 0.0729 and 0.4341, respectively). Strenuous activity and sedentary activity are associated with the incidence of vertebral fractures, although the association may not be linear. The pattern of association between physical activity and vertebral fractures appears to be

  16. Dose-Response Association Between Physical Activity and Incident Hypertension: A Systematic Review and Meta-Analysis of Cohort Studies.

    Science.gov (United States)

    Liu, Xuejiao; Zhang, Dongdong; Liu, Yu; Sun, Xizhuo; Han, Chengyi; Wang, Bingyuan; Ren, Yongcheng; Zhou, Junmei; Zhao, Yang; Shi, Yuanyuan; Hu, Dongsheng; Zhang, Ming

    2017-05-01

    Despite the inverse association between physical activity (PA) and incident hypertension, a comprehensive assessment of the quantitative dose-response association between PA and hypertension has not been reported. We performed a meta-analysis, including dose-response analysis, to quantitatively evaluate this association. We searched PubMed and Embase databases for articles published up to November 1, 2016. Random effects generalized least squares regression models were used to assess the quantitative association between PA and hypertension risk across studies. Restricted cubic splines were used to model the dose-response association. We identified 22 articles (29 studies) investigating the risk of hypertension with leisure-time PA or total PA, including 330 222 individuals and 67 698 incident cases of hypertension. The risk of hypertension was reduced by 6% (relative risk, 0.94; 95% confidence interval, 0.92-0.96) with each 10 metabolic equivalent of task h/wk increment of leisure-time PA. We found no evidence of a nonlinear dose-response association of PA and hypertension ( P nonlinearity =0.094 for leisure-time PA and 0.771 for total PA). With the linear cubic spline model, when compared with inactive individuals, for those who met the guidelines recommended minimum level of moderate PA (10 metabolic equivalent of task h/wk), the risk of hypertension was reduced by 6% (relative risk, 0.94; 95% confidence interval, 0.92-0.97). This meta-analysis suggests that additional benefits for hypertension prevention occur as the amount of PA increases. © 2017 American Heart Association, Inc.

  17. Preliminary incidence and trends of infection with pathogens transmitted commonly through food - Foodborne Diseases Active Surveillance Network, 10 U.S. sites, 2006-2014.

    Science.gov (United States)

    Crim, Stacy M; Griffin, Patricia M; Tauxe, Robert; Marder, Ellyn P; Gilliss, Debra; Cronquist, Alicia B; Cartter, Matthew; Tobin-D'Angelo, Melissa; Blythe, David; Smith, Kirk; Lathrop, Sarah; Zansky, Shelley; Cieslak, Paul R; Dunn, John; Holt, Kristin G; Wolpert, Beverly; Henao, Olga L

    2015-05-15

    Foodborne illnesses represent a substantial, yet largely preventable, health burden in the United States. In 10 U.S. geographic areas, the Foodborne Diseases Active Surveillance Network (FoodNet) monitors the incidence of laboratory-confirmed infections caused by nine pathogens transmitted commonly through food. This report summarizes preliminary 2014 data and describes changes in incidence compared with 2006-2008 and 2011-2013. In 2014, FoodNet reported 19,542 infections, 4,445 hospitalizations, and 71 deaths. The incidence of Shiga toxin-producing Escherichia coli (STEC) O157 and Salmonella enterica serotype Typhimurium infections declined in 2014 compared with 2006-2008, and the incidence of infection with Campylobacter, Vibrio, and Salmonella serotypes Infantis and Javiana was higher. Compared with 2011-2013, the incidence of STEC O157 and Salmonella Typhimurium infections was lower, and the incidence of STEC non-O157 and Salmonella serotype Infantis infections was higher in 2014. Despite ongoing food safety efforts, the incidence of many infections remains high, indicating that further prevention measures are needed to make food safer and achieve national health objectives.

  18. Melatonin Improves the Photosynthetic Carbon Assimilation and Antioxidant Capacity in Wheat Exposed to Nano-ZnO Stress

    Directory of Open Access Journals (Sweden)

    Zhiyu Zuo

    2017-10-01

    Full Text Available The release of nanoparticles into the environment is inevitable, which has raised global environmental concern. Melatonin is involved in various stress responses in plants. The present study investigated the effects of melatonin on photosynthetic carbon (C assimilation and plant growth in nano-ZnO stressed plants. It was found that melatonin improved the photosynthetic C assimilation in nano-ZnO stressed wheat plants, mainly due to the enhanced photosynthetic energy transport efficiency, higher chlorophyll concentration and higher activities of Rubisco and ATPases. In addition, melatonin enhanced the activities of antioxidant enzymes to protect the photosynthetic electron transport system in wheat leaves against the oxidative burst caused by nano-ZnO stress. These results suggest that melatonin could improve the tolerance of wheat plants to nano-ZnO stress.

  19. Alternating electron and proton transfer steps in photosynthetic water oxidation.

    Science.gov (United States)

    Klauss, André; Haumann, Michael; Dau, Holger

    2012-10-02

    Water oxidation by cyanobacteria, algae, and plants is pivotal in oxygenic photosynthesis, the process that powers life on Earth, and is the paradigm for engineering solar fuel-production systems. Each complete reaction cycle of photosynthetic water oxidation requires the removal of four electrons and four protons from the catalytic site, a manganese-calcium complex and its protein environment in photosystem II. In time-resolved photothermal beam deflection experiments, we monitored apparent volume changes of the photosystem II protein associated with charge creation by light-induced electron transfer (contraction) and charge-compensating proton relocation (expansion). Two previously invisible proton removal steps were detected, thereby filling two gaps in the basic reaction-cycle model of photosynthetic water oxidation. In the S(2) → S(3) transition of the classical S-state cycle, an intermediate is formed by deprotonation clearly before electron transfer to the oxidant (Y Z OX). The rate-determining elementary step (τ, approximately 30 µs at 20 °C) in the long-distance proton relocation toward the protein-water interface is characterized by a high activation energy (E(a) = 0.46 ± 0.05 eV) and strong H/D kinetic isotope effect (approximately 6). The characteristics of a proton transfer step during the S(0) → S(1) transition are similar (τ, approximately 100 µs; E(a) = 0.34 ± 0.08 eV; kinetic isotope effect, approximately 3); however, the proton removal from the Mn complex proceeds after electron transfer to . By discovery of the transient formation of two further intermediate states in the reaction cycle of photosynthetic water oxidation, a temporal sequence of strictly alternating removal of electrons and protons from the catalytic site is established.

  20. Salt-tolerant rootstock increases yield of pepper under salinity through maintenance of photosynthetic performance and sinks strength.

    Science.gov (United States)

    Penella, Consuelo; Landi, Marco; Guidi, Lucia; Nebauer, Sergio G; Pellegrini, Elisa; San Bautista, Alberto; Remorini, Damiano; Nali, Cristina; López-Galarza, Salvador; Calatayud, Angeles

    2016-04-01

    The performance of a salt-tolerant pepper (Capsicum annuum L.) accession (A25) utilized as a rootstock was assessed in two experiments. In a first field experiment under natural salinity conditions, we observed a larger amount of marketable fruit (+75%) and lower Blossom-end Root incidence (-31%) in commercial pepper cultivar Adige (A) grafted onto A25 (A/A25) when compared with ungrafted plants. In order to understand this behavior a second greenhouse experiment was conducted to determine growth, mineral partitioning, gas exchange and chlorophyll a fluorescence parameters, antioxidant systems and proline content in A and A/A25 plants under salinity conditions (80 mM NaCl for 14 days). Salt stress induced significantly stunted growth of A plants (-40.6% of leaf dry weight) compared to the control conditions, while no alterations were observed in A/A25 at the end of the experiment. Accumulation of Na(+) and Cl(-) in leaves and roots was similar in either grafted or ungrafted plants. Despite the activation of protective mechanisms (increment of superoxide dismutase, catalase, ascorbate peroxidase activity and non-photochemical quenching), A plants showed severely reduced photosynthetic CO2 assimilation (-45.6% of AN390) and substantial buildup of malondialdehyde (MDA) by-product, suggesting the inability to counteract salt-triggered damage. In contrast, A/A25 plants, which had a constitutive enhanced root apparatus, were able to maintain the shoot and root growth under salinity conditions by supporting the maintained photosynthetic performance. No increases in catalase and ascorbate peroxidase activities were observed in response to salinity, and MDA levels increased only slightly; indicating that alleviation of oxidative stress did not occur in A/A25 plants. In these plants the increased proline levels could protect enzymatic stability from salt-triggered damage, preserving the photosynthetic performance. The results could indicate that salt stress was vanished by

  1. Changes of Photosynthetic Behaviors in Kappaphycus alvarezii Infected by Epiphyte

    Directory of Open Access Journals (Sweden)

    Tong Pang

    2011-01-01

    Full Text Available Epiphytic filamentous algae (EFA were noted as a serious problem to reduce the production and quality of K. alvarezii. The morphological studies revealed that the main epiphyte on K. alvarezii was Neosiphonia savatieri in China. Though the harmful effects of EFA on the production of K. alvarezii have been reported, the detailed mechanism of the N. savatieri in limiting the production of K. alvarezii has not been studied yet. The present paper studied the effects of N. savatieri infection on photosynthetic behaviors in K. alvarezii by detecting chlorophyll fluorescence transient in vivo. The results revealed that damage of oxygen-evolving complex (OEC, decrease of active reaction centers (RCs, and the plastoquinone (PQ pool as well as significant reduction in the performance indexes (PI of PSII were caused by the infection of N. savatieri. The influence of N. savatieri on photosynthetic activity of K. alvarezii should be one of the important reasons to reduce the production of K. alvarezii infected by N. savatieri.

  2. Chlorophyll fluorescence analysis revealed essential roles of FtsH 11 protease in regulation of the adaptive responses of photosynthetic systems to high temperature

    Science.gov (United States)

    Background: Photosynthetic systems are known to be sensitive to high temperature stress. To maintain a relatively “normal” level of photosynthetic activities, plants employ a variety of adaptive mechanisms in response to environmental temperature fluctuations. Previously, we reported that the chloro...

  3. Diel tuning of photosynthetic systems in ice algae at Saroma-ko Lagoon, Hokkaido, Japan

    Science.gov (United States)

    Aikawa, Shimpei; Hattori, Hiroshi; Gomi, Yasushi; Watanabe, Kentaro; Kudoh, Sakae; Kashino, Yasuhiro; Satoh, Kazuhiko

    Ice algae are the major primary producers in seasonally ice-covered oceans during the cold season. Diurnal change in solar radiation is inevitable for ice algae, even beneath seasonal sea ice in lower-latitude regions. In this work, we focused on the photosynthetic response of ice algae under diurnally changing irradiance in Saroma-ko Lagoon, Japan. Photosynthetic properties were assessed by pulse-amplitude modulation (PAM) fluorometry. The species composition remained almost the same throughout the investigation. The maximum electron transport rate ( rETRmax), which indicates the capacity of photosynthetic electron transport, increased from sunrise until around noon and decreased toward sunset, with no sign of the afternoon depression commonly observed in other photosynthetic organisms. The level of non-photochemical quenching, which indicates photoprotection activity by dissipating excess light energy via thermal processes, changed with diurnal variations in irradiance. The pigment composition appeared constant, except for xanthophyll cycle pigments, which changed irrespective of irradiance. These results indicate that ice algae tune their photosynthetic system harmonically to achieve efficient photosynthesis under diurnally changing irradiance, while avoiding damage to photosystems. This regulation system may be essential for productive photosynthesis in ice algae.

  4. Photosynthetic Rates of Citronella and Lemongrass 1

    Science.gov (United States)

    Herath, H. M. Walter; Ormrod, Douglas P.

    1979-01-01

    Ten selections of citronella (Cymbopogon nardus [L.] Rendle) were grown at 32/27, 27/21, or 15/10 C day/night temperatures, and plants from three populations of lemongrass (Cymbopogon citratus [D.C.] Stapf from Japan or Sri Lanka and Cymbopogon flexuosus [D.C.] Stapf from India) were grown at 8- or 15-hour photoperiods. Net photosynthetic rates of mature leaves were measured in a controlled environment at 25 C and 260 microeinsteins per meter2 per second. Rates declined with increasing leaf age, and from the tip to the base of the leaf blade. Rates for citronella leaves grown at 15/10 C were extremely low for all selections. Highest rates of net photosynthesis were recorded for four selections grown at 27/21 C and for two selections grown at 32/27 C. Lemongrass grown at 8-hour photoperiod had higher photosynthetic rates than that grown at 15-hour photoperiod. PMID:16660737

  5. Photosynthetic reaction center protein in nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Hajdu, Kata; Szabo, Tibor; Magyar, Melinda; Nagy, Laszlo [Department of Medical Physics and Informatics, University of Szeged, 6720 Szeged (Hungary); Bencsik, Gabor [Department of Physical Chemistry and Materials Science, University of Szeged, 6720 Szeged (Hungary); Nemeth, Zoltan; Hernadi, Klara [Department of Applied and Environmental Chemistry, University of Szeged, 6720 Szeged (Hungary); Nagy, Krisztina; Varo, Gyoergy [Institute of Biophysics, BRC, Szeged, 6726 Szeged (Hungary); Magrez, Arnaud; Forro, Laszlo [Institute of Physics of Complex Matter, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland)

    2011-11-15

    Photosynthetic reaction center (RC) is one of the most important proteins, because it is Nature's solar battery converting light energy into chemical potential in the photosynthetic membrane assuring conditions for carbon reduction in cells. Although it is developed in nanometer scale, and is working in nanoscopic power, this is the protein that assures the energy input practically for the whole biosphere on Earth. The extremely large quantum yield of the primary charge separation (close to 100%) in the RC offers a big challenge to use it in nanodevices. Results of structural (AFM, EM), optical, and electro chemical investigations on RC bio-nanocomposite materials based on different carrier matrices (e.g., CNTs, ITO) will be presented. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. What have we learned from reporting safety incidents in the Surgical Block?: Cross-sectional descriptive study of two-years of activity of a multidisciplinary analytical group.

    Science.gov (United States)

    Caba Barrientos, F; Rodríguez Morillo, A; Galisteo Domínguez, R; Del Nozal Nalda, M; Almeida González, C V; Echevarría Moreno, M

    2018-01-17

    Incident Reporting Systems (IRS) are considered a tool that facilitates learning and safety culture. Using the experience gained with SENSAR, we evaluated the feasibility and the activity of a multidisciplinary group analyzing incidents in the surgical patient notified to a general community system, that of the Observatory for Patient Safety (OPS). Cross-sectional observational study planned for two years. After training in the analysis, a multidisciplinary group was created in terms of specialties and professional categories, which would analyze the incidents in the surgical patient notified to the OPS. Incidents are classified and their circumstances analyzed. Between March 2015 and 2017, 95 incidents were reported (4 by non-professionals). Doctors reported more than nurses, at 54 (56.84%) vs. 37 (38.94%). The anaesthesia unit reported most at 46 (48.42%) (P=.025). The types of incidents mainly related to the care procedure (30.52%); to the preoperative period (42.10%); and to the place, the surgical area (48.42%). Significant differences were detected according to the origin of the notifier (P=.03). No harm, or minor morbidity, constituted 88% of the incidents. Errors were identified in 79%. The analysis of the incidents directed the measures to be taken. The activity undertaken by the multidisciplinary analytical group during the period of study facilitated knowledge of the system among the professionals and enabled the identification of areas for improvement in the Surgical Block at different levels. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  7. Nonclassical energy transfer in photosynthetic FMO complex

    Directory of Open Access Journals (Sweden)

    Abramavicius Vytautas

    2013-03-01

    Full Text Available Excitation energy transfer in a photosynthetic FMO complex has been simulated using the stochastic Schrödinger equation. Fluctuating chromophore transition energies are simulated from the quantum correlation function which allows to properly include the finite temperature. The resulting excitation dynamics shows fast thermalization of chromophore occupations into proper thermal equilibrium. The relaxation process is characterized by entropy dynamics, which shows nonclassical behavior.

  8. The effect of starvation on plastid number and photosynthetic performance in the kleptoplastidic dinoflagellate Amylax triacantha.

    Science.gov (United States)

    Kim, Miran; Kim, Kwang Young; Nam, Seung Won; Shin, Woongghi; Yih, Wonho; Park, Myung Gil

    2014-01-01

    The dinoflagellate Amylax triacantha is known to retain plastids of cryptophyte origin by engulfing the mixotrophic ciliate Mesodinium rubrum, itself a consumer of cryptophytes. However, there is no information on the fate of the prey's organelles and the photosynthetic performance of the newly retained plastids in A. triacantha. In this study, we conducted a starvation experiment to observe the intracellular organization of the prey's organelles and temporal changes in the photosynthetic efficiency of acquired plastids in A. triacantha. The ultrastructural observations revealed that while the chloroplast-mitochondria complexes and nucleus of cryptophyte were retained by A. triacantha, other ciliate organelles were digested in food vacuoles. Acquired plastids were retained in A. triacantha for about 1 mo and showed photosynthetic activities for about 18 d when measured by a pulse-amplitude modulation fluorometer. © 2014 The Author(s) Journal of Eukaryotic Microbiology © 2014 International Society of Protistologists.

  9. Interactive effects of cadmium and acid rain on photosynthetic light reaction in soybean seedlings.

    Science.gov (United States)

    Sun, Zhaoguo; Wang, Lihong; Chen, Minmin; Wang, Lei; Liang, Chanjuan; Zhou, Qing; Huang, Xiaohua

    2012-05-01

    Interactive effects of cadmium (Cd(2+)) and acid rain on photosynthetic light reaction in soybean seedlings were investigated under hydroponic conditions. Single treatment with Cd(2+) or acid rain and the combined treatment decreased the content of chlorophyll, Hill reaction rate, the activity of Mg(2+)-ATPase, maximal photochemical efficiency and maximal quantum yield, increased initial fluorescence and damaged the chloroplast structure in soybean seedlings. In the combined treatment, the change in the photosynthetic parameters and the damage of chloroplast structure were stronger than those of any single pollution. Meanwhile, Cd(2+) and acid rain had the interactive effects on the test indices in soybean seedlings. The results indicated that the combined pollution of Cd(2+) and acid rain aggravated the toxic effect of the single pollution of Cd(2+) or acid rain on the photosynthetic parameters due to the serious damage to the chloroplast structure. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Effect of sodium chloride on photosynthetic 14CO2 assimilation in Portulaca oleracea Linn

    International Nuclear Information System (INIS)

    Joshi, G.V.; Karadge, B.A.

    1979-01-01

    Effect of NaCl on ion uptake, photosynthetic rate and photosynthetic products in a C 4 non-CAM succulent, P. oleracea has been investigated. NaCl causes accumulation of Na as well as Cl ions with decrease in K and Ca contents. Chlorophylls and photosynthetic 14 CO 2 fixation rates are adversely affected due to sodium chloride salinity. Plants grown in the presence of NaCl show increase in C 4 acid percentage with increase in labelling of organic acids in light. Labelling of amino acids (particularly alanine) and sugars (sucrose) is affected by NaCl. Enzyme studies reveal that PEP-carboxylase is stimulated at all concentrations of NaCl but higher concentrations affected the activity of RuBP-Carboxylase. (author)

  11. A Clinical Algorithm to Identify HIV Patients at High Risk for Incident Active Tuberculosis: A Prospective 5-Year Cohort Study.

    Directory of Open Access Journals (Sweden)

    Susan Shin-Jung Lee

    Full Text Available Predicting the risk of tuberculosis (TB in people living with HIV (PLHIV using a single test is currently not possible. We aimed to develop and validate a clinical algorithm, using baseline CD4 cell counts, HIV viral load (pVL, and interferon-gamma release assay (IGRA, to identify PLHIV who are at high risk for incident active TB in low-to-moderate TB burden settings where highly active antiretroviral therapy (HAART is routinely provided.A prospective, 5-year, cohort study of adult PLHIV was conducted from 2006 to 2012 in two hospitals in Taiwan. HAART was initiated based on contemporary guidelines (CD4 count < = 350/μL. Cox regression was used to identify the predictors of active TB and to construct the algorithm. The validation cohorts included 1455 HIV-infected individuals from previous published studies. Area under the receiver operating characteristic (ROC curve was calculated.Seventeen of 772 participants developed active TB during a median follow-up period of 5.21 years. Baseline CD4 < 350/μL or pVL ≥ 100,000/mL was a predictor of active TB (adjusted HR 4.87, 95% CI 1.49-15.90, P = 0.009. A positive baseline IGRA predicted TB in patients with baseline CD4 ≥ 350/μL and pVL < 100,000/mL (adjusted HR 6.09, 95% CI 1.52-24.40, P = 0.01. Compared with an IGRA-alone strategy, the algorithm improved the sensitivity from 37.5% to 76.5%, the negative predictive value from 98.5% to 99.2%. Compared with an untargeted strategy, the algorithm spared 468 (60.6% from unnecessary TB preventive treatment. Area under the ROC curve was 0.692 (95% CI: 0.587-0.798 for the study cohort and 0.792 (95% CI: 0.776-0.808 and 0.766 in the 2 validation cohorts.A validated algorithm incorporating the baseline CD4 cell count, HIV viral load, and IGRA status can be used to guide targeted TB preventive treatment in PLHIV in low-to-moderate TB burden settings where HAART is routinely provided to all PLHIV. The implementation of this algorithm will avoid unnecessary

  12. Prioritization of copper for the use in photosynthetic electron transport in developing leaves of hybrid poplar

    Directory of Open Access Journals (Sweden)

    Muhammad eShahbaz

    2015-06-01

    Full Text Available Plastocyanin is an essential and abundant copper protein required for photosynthesis in higher plants. Severe copper deprivation has the potential to cause a defect in photosynthetic electron transport due to a lack in plastocyanin. The Cu-microRNAs, which are up-regulated under Cu deficiency, down-regulate the expression of target Cu proteins other than plastocyanin, cytochrome-c oxidase and the ethylene receptors. It has been proposed that this mechanism saves Cu for plastocyanin maturation. We aimed to test how hybrid poplar, a species that has capacity to rapidly expand its photosynthetically active tissue, responds to variations in Cu availability over time. Measurement of chlorophyll fluorescence after Cu depletion revealed a drastic effect on photosynthesis in hybrid poplar. The decrease in photosynthetic capacity was correlated with a reduction in plastocyanin protein levels. Compared to older leaves, plastocyanin decreased more strongly in developing leaves, which also lost more photosynthetic electron transport capacity. The effect of Cu depletion on older and more developed leaves was minor and these leaves maintained much of their photosynthetic capacity. Interestingly, upon resupply of Cu to the medium a very rapid recovery of Cu levels was seen in the younger leaves with a concomitant rise in the expression and activity of plastocyanin. In contrast, the expression of those Cu proteins, which are targets of microRNAs was under the same circumstances delayed. At the same time, Cu resupply had only minor effects on the older leaves. The data suggest a model where rapid recovery of photosynthetic capacity in younger leaves is made possible by a preferred allocation of Cu to plastocyanin in younger leaves, which is supported by Cu-microRNA expression.

  13. The mechanisms by which phenanthrene affects the photosynthetic apparatus of cucumber leaves.

    Science.gov (United States)

    Jin, Liqiao; Che, Xingkai; Zhang, Zishan; Li, Yuting; Gao, Huiyuan; Zhao, Shijie

    2017-02-01

    Phenanthrene is a polycyclic aromatic hydrocarbon (PAH) that is widely distributed in the environment and seriously affects the growth and development of plants. To clarify the mechanisms of the direct effects of phenanthrene on the plant photosynthetic apparatus, we measured short-term phenanthrene-treated cucumber leaves. Phenanthrene inhibited Rubisco carboxylation activity, decreasing photosynthesis rates (Pn). And phenanthrene inhibited photosystem II (PSII) activity, thereby blocking photosynthetic electron transport. The inhibition of the light and dark reactions decreased the photosynthetic electron transport rate (ETR) and increased the excitation pressure (1-qP). Under high light, the maximum photochemical efficiency of photosystem II (F v /F m ) in phenanthrene-treated cucumber leaves decreased significantly, but photosystem I (PSI) activity (Δ I/I o ) did not. Phenanthrene also caused a J-point rise in the OJIP curve under high light, which indicated that the acceptor side of PSII Q A to Q B electron transfer was restricted. This was primarily due to the net degradation of D1 protein, which is caused by the accumulation of reactive oxygen species (ROS) in phenanthrene-treated cucumber leaves under high light. This study demonstrated that phenanthrene could directly inhibit photosynthetic electron transport and Rubisco carboxylation activity to decrease net Pn. Under high light, phenanthrene caused the accumulation of ROS, resulting in net increases in D1 protein degradation and consequently causing PSII photoinhibition. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Wheelchair incidents

    NARCIS (Netherlands)

    Drongelen AW van; Roszek B; Hilbers-Modderman ESM; Kallewaard M; Wassenaar C; LGM

    2002-01-01

    This RIVM study was performed to gain insight into wheelchair-related incidents with powered and manual wheelchairs reported to the USA FDA, the British MDA and the Dutch Center for Quality and Usability Research of Technical Aids (KBOH). The data in the databases do not indicate that incidents with

  15. [Health examination in future at the era of low tuberculosis incidence--from contacts examination toward active epidemiological studies].

    Science.gov (United States)

    Maeda, Hideo; Shirai, Chika

    2013-03-01

    Japan is still "intermediate burden" country as medium-incidence of tuberculosis (TB). But the incidence of TB varies by public health units. The priority for TB control would be lowering in the areas where the incidence of TB is relatively low. In addition, younger age groups get low prevalence of TB infection than elderly persons. As a result, fewer experiences for TB diagnosis and treatment in the hospital and the medical facility would cause the delay in the detection of TB patients which eventually cause outbreaks. Although there are differences in population density and population mobility between urban and rural areas, the socially economic vulnerable patients and foreign patients are the common risks. Any public health units' policies of TB should correspond to the individual situation. At the era of low tuberculosis incidence, the infection risk is to be "From ubiquitous to the uneven distribution". This makes TB detection much more difficult. At this symposium, each speaker presented the case for actually experienced with QFT test and/or VNTR analysis. They mainly focused on the paradigm shift in TB control which is indispensable for resolving the gaps in regional differences and the differences in diagnostic capability. Although the cases in this symposium were not for the low incidence situation, the pioneering approaches presented here would boost the future application of QFT and VNTR analysis nationwide. The discussions also partially covered the technical infrastructure for molecular epidemiology which covers the whole country. By making full use of QFT test and VNTR analysis as a contact screening tool, we can appropriately understand the risk of TB infection in the region from a buildup of bacteria and patient information. Now is the time to prepare for. Active surveillance of TB by this way would clarify the risk of the disease and lead to the advocacy essential for the resolution. 1. Current situation and challenge of contact survey by using QFT

  16. Emergency imaging after a mass casualty incident: role of the radiology department during training for and activation of a disaster management plan

    NARCIS (Netherlands)

    Berger, Ferco H.; Körner, Markus; Bernstein, Mark P.; Sodickson, Aaron D.; Beenen, Ludo F.; McLaughlin, Patrick D.; Kool, Digna R.; Bilow, Ronald M.

    2016-01-01

    In the setting of mass casualty incidents (MCIs), hospitals need to divert from normal routine to delivering the best possible care to the largest number of victims. This should be accomplished by activating an established hospital disaster management plan (DMP) known to all staff through prior

  17. Comparison of photosynthetic induction and transient limitations during the induction phase in young and mature leaves from three poplar clones.

    Science.gov (United States)

    Urban, Otmar; Sprtová, Mirka; Kosvancová, Martina; Tomásková, Ivana; Lichtenthaler, Hartmut K; Marek, Michal V

    2008-08-01

    We tested the hypothesis that leaf age affects photosynthetic induction, because conductance to CO2 diffusion usually decreases with increasing leaf age. Photosynthetic inductions, primarily determined by the light modulation of Rubisco activity and stomatal opening, were investigated in both young and mature leaves, as defined by leaf plastochron index (LPI), from three poplar clones: Populus alba L., P. nigra L. and P. x euramericana (Dode) Guinier. In all clones, maximum assimilation rates (A max), maximum stomatal conductance (G Smax) and dark respiration rates (RD) were higher in young leaves (LPI = 3-5) than in mature leaves (LPI = 10-14), and A max decreased from P. alba via P. x euramericana to P. nigra. The clones with high photosynthetic capacity had low induction states 60 s after leaf illumination (IS60; indicating a slow initial induction phase), and required less time to reach 90% photosynthetic induction (T90). In contrast, the clone with the lowest photosynthetic capacity (P. nigra) exhibited high IS60 (high initial induction state) but a long induction time (high T90). A comparison of mature leaves with young leaves revealed significantly (P clones, young leaves exhibited a lower percentage of maximum transient stomatal limitation during photosynthetic induction (4-9%) compared with mature leaves (16-30%). Transient biochemical limitation, assessed on the basis of the time constants of Rubisco activation (tau), was significantly higher in mature leaves than in young leaves of P. alba; whereas there were no significant differences in tau between young and mature leaves of the other poplar clones. Thus, our hypothesis that leaf age affects photosynthetic induction was confirmed at the level of transient stomatal limitation, which was significantly higher in mature leaves than in young leaves in all clones. For the induction parameters IS60, T90 and tau, photosynthetic induction was more clone-specific and was dependent on leaf age only in some cases

  18. Photosynthetic Response of Soybean to Microclimate in 26-Year-Old Tree-Based Intercropping Systems in Southern Ontario, Canada.

    Directory of Open Access Journals (Sweden)

    Xiaobang Peng

    Full Text Available In order to study the effect of light competition and microclimatic modifications on the net assimilation (NA, growth and yield of soybean (Glycine max L. as an understory crop, three 26-year-old soybean-tree (Acer saccharinum Marsh., Populus deltoides X nigra, Juglans nigra L. intercropping systems were examined. Tree competition reduced photosynthetically active radiation (PAR incident on soybeans and reduced net assimilation, growth and yield of soybean. Soil moisture of 20 cm depth close (< 3 m to the tree rows was also reduced. Correlation analysis showed that NA and soil water content were highly correlated with growth and yield of soybean. When compared with the monoculture soybean system, the relative humidity (RH of the poplar-soybean, silver maple-soybean, and black walnut-soybean intercropped systems was increased by 7.1%, 8.0% and 5.9%, soil water content was reduced by 37.8%, 26.3% and 30.9%, ambient temperature was reduced by 1.3°C, 1.4°C and 1.0°C, PAR was reduced by 53.6%, 57.9% and 39.9%, and air CO2 concentration was reduced by 3.7μmol·mol(-1, 4.2μmol·mol(-1 and 2.8μmol·mol(-1, respectively. Compared to the monoculture, the average NA of soybean in poplar, maple and walnut treatments was also reduced by 53.1%, 67.5% and 46.5%, respectively. Multivariate stepwise regression analysis showed that PAR, ambient temperature and CO2 concentration were the dominant factors influencing net photosynthetic rate.

  19. Photosynthetic Response of Soybean to Microclimate in 26-Year-Old Tree-Based Intercropping Systems in Southern Ontario, Canada.

    Science.gov (United States)

    Peng, Xiaobang; Thevathasan, Naresh V; Gordon, Andrew M; Mohammed, Idris; Gao, Pengxiang

    2015-01-01

    In order to study the effect of light competition and microclimatic modifications on the net assimilation (NA), growth and yield of soybean (Glycine max L.) as an understory crop, three 26-year-old soybean-tree (Acer saccharinum Marsh., Populus deltoides X nigra, Juglans nigra L.) intercropping systems were examined. Tree competition reduced photosynthetically active radiation (PAR) incident on soybeans and reduced net assimilation, growth and yield of soybean. Soil moisture of 20 cm depth close (< 3 m) to the tree rows was also reduced. Correlation analysis showed that NA and soil water content were highly correlated with growth and yield of soybean. When compared with the monoculture soybean system, the relative humidity (RH) of the poplar-soybean, silver maple-soybean, and black walnut-soybean intercropped systems was increased by 7.1%, 8.0% and 5.9%, soil water content was reduced by 37.8%, 26.3% and 30.9%, ambient temperature was reduced by 1.3°C, 1.4°C and 1.0°C, PAR was reduced by 53.6%, 57.9% and 39.9%, and air CO2 concentration was reduced by 3.7μmol·mol(-1), 4.2μmol·mol(-1) and 2.8μmol·mol(-1), respectively. Compared to the monoculture, the average NA of soybean in poplar, maple and walnut treatments was also reduced by 53.1%, 67.5% and 46.5%, respectively. Multivariate stepwise regression analysis showed that PAR, ambient temperature and CO2 concentration were the dominant factors influencing net photosynthetic rate.

  20. A rice plastidial nucleotide sugar epimerase is involved in galactolipid biosynthesis and improves photosynthetic efficiency.

    Directory of Open Access Journals (Sweden)

    Chunlai Li

    2011-07-01

    Full Text Available Photosynthesis is the final determinator for crop yield. To gain insight into genes controlling photosynthetic capacity, we selected from our large T-DNA mutant population a rice stunted growth mutant with decreased carbon assimilate and yield production named photoassimilate defective1 (phd1. Molecular and biochemical analyses revealed that PHD1 encodes a novel chloroplast-localized UDP-glucose epimerase (UGE, which is conserved in the plant kingdom. The chloroplast localization of PHD1 was confirmed by immunoblots, immunocytochemistry, and UGE activity in isolated chloroplasts, which was approximately 50% lower in the phd1-1 mutant than in the wild type. In addition, the amounts of UDP-glucose and UDP-galactose substrates in chloroplasts were significantly higher and lower, respectively, indicating that PHD1 was responsible for a major part of UGE activity in plastids. The relative amount of monogalactosyldiacylglycerol (MGDG, a major chloroplast membrane galactolipid, was decreased in the mutant, while the digalactosyldiacylglycerol (DGDG amount was not significantly altered, suggesting that PHD1 participates mainly in UDP-galactose supply for MGDG biosynthesis in chloroplasts. The phd1 mutant showed decreased chlorophyll content, photosynthetic activity, and altered chloroplast ultrastructure, suggesting that a correct amount of galactoglycerolipids and the ratio of glycolipids versus phospholipids are necessary for proper chloroplast function. Downregulated expression of starch biosynthesis genes and upregulated expression of sucrose cleavage genes might be a result of reduced photosynthetic activity and account for the decreased starch and sucrose levels seen in phd1 leaves. PHD1 overexpression increased photosynthetic efficiency, biomass, and grain production, suggesting that PHD1 plays an important role in supplying sufficient galactolipids to thylakoid membranes for proper chloroplast biogenesis and photosynthetic activity. These

  1. Factors associated with syphilis incidence in the HIV-infected in the era of highly active antiretrovirals

    Science.gov (United States)

    Shilaih, Mohaned; Marzel, Alex; Braun, Dominique L.; Scherrer, Alexandra U.; Kovari, Helen; Young, Jim; Calmy, Alexandra; Darling, Katharine; Battegay, Manuel; Hoffmann, Matthias; Bernasconi, Enos; Thurnheer, Maria C.; Günthard, Huldrych F.; Kouyos, Roger D.

    2017-01-01

    Abstract After several years of steady decline, syphilis is reemerging globally as a public health hazard, especially among people living with human immunodeficiency virus (HIV). Syphilis resurgence is observed mainly in men who have sex with men (MSM), yet other transmission groups are affected too. In this manuscript, we study the factors associated with syphilis incidence in the Swiss HIV cohort study in the era of highly effective antiretrovirals. Using parametric interval censored models with fixed and time-varying covariates, we studied the immunological, behavioral, and treatment-related elements associated with syphilis incidence in 3 transmission groups: MSM, heterosexuals, and intravenous drug users. Syphilis incidence has been increasing annually since 2005, with up to 74 incident cases per 1000 person-years in 2013, with MSM being the population with the highest burden (92% of cases). While antiretroviral treatment (ART) in general did not affect syphilis incidence, nevirapine (NVP) was associated with a lower hazard of syphilis incidence (multivariable hazard ratio 0.5, 95% confidence interval 0.2–1.0). We observed that condomless sex and younger age were associated with higher syphilis incidence. Moreover, time-updated CD4, nadir CD4, and CD8 cell counts were not associated with syphilis incidence. Finally, testing frequency higher than the recommended once a year routine testing was associated with a 2-fold higher risk of acquiring syphilis. Condomless sex is the main driver of syphilis resurgence in the Swiss HIV Cohort study; ART and immune reconstitution provide no protection against syphilis. This entails targeted interventions and frequent screening of high-risk populations. There is no known effect of NVP on syphilis; therefore, further clinical, epidemiological, and microbiological investigation is necessary to validate our observation. PMID:28079818

  2. Responses of photosynthetic capacity to soil moisture gradient in perennial rhizome grass and perennial bunchgrass

    Directory of Open Access Journals (Sweden)

    Zhou Guangsheng

    2011-01-01

    Full Text Available Abstract Background Changing water condition represents a dramatic impact on global terrestrial ecosystem productivity, mainly by limiting plant functions, including growth and photosynthesis, particularly in arid and semiarid areas. However, responses of the potential photosynthetic capacity to soil water status in a wide range of soil moisture levels, and determination of their thresholds are poorly understood. This study examined the response patterns of plant photosynthetic capacity and their thresholds to a soil moisture gradient in a perennial rhizome grass, Leymus chinensis, and a perennial bunchgrass, Stipa grandis, both dominant in the Eurasian Steppe. Results Severe water deficit produced negative effects on light-saturated net CO2 assimilation rate (Asat, stomatal conductance (gs, mesophyll conductance (gm, maximum carboxylation velocity (Vc,max, and maximal efficiency of PSII photochemistry (Fv/Fm. Photosynthetic activity was enhanced under moderate soil moisture with reductions under both severe water deficit and excessive water conditions, which may represent the response patterns of plant growth and photosynthetic capacity to the soil water gradient. Our results also showed that S. grandis had lower productivity and photosynthetic potentials under moderate water status, although it demonstrated generally similar relationship patterns between photosynthetic potentials and water status relative to L. chinensis. Conclusions The experiments tested and confirmed the hypothesis that responsive threshold points appear when plants are exposed to a broad water status range, with different responses between the two key species. It is suggested that vegetation structure and function may be shifted when a turning point of soil moisture occurs, which translates to terms of future climatic change prediction in semiarid grasslands.

  3. Photosynthetic performance of Jatropha curcas fruits.

    Science.gov (United States)

    Ranjan, Sanjay; Singh, Ruchi; Soni, Devendra K; Pathre, Uday V; Shirke, Pramod A

    2012-03-01

    Jatropha curcas (L.) trees under north Indian conditions (Lucknow) produce fruits in two major flushes, once during autumn-winter (October-December). The leaves at this time are at the senescence stages and already shedding. The second flush of fruit setting occurs during the summer (April-June) after the leaves have formed during spring (March-April). Photosynthetic performance of detached jatropha fruits was studied at three developmental stages, immature, mature and ripe fruits. Studies were made in both winter and summer fruits in response to light, temperature and vapour pressure deficit (VPD) under controlled conditions to assess the influence of these environmental factors on the photosynthetic performance of jatropha fruits. Immature fruits showed high light saturating point of around 2000 μmol m(-2) s(-1). High VPD did not show an adverse effect on the fruit A. Stomatal conductance (g(s)) showed an inverse behaviour to increasing VPD, however, transpiration (E) was not restricted by the increasing VPD in both seasons. During winter in absence of leaves on the jatropha tree the fruits along with the bark contributes maximum towards photoassimilation. Dark respiration rates (R(d)) monitored in fruit coat and seeds independently, showed maximum R(d) in seeds of mature fruit and these were about five times more than its fruit coat, reflecting the higher energy requirement of the developing fruit during maximum oil synthesis stage. Photosynthesis and fluorescence parameters studied indicate that young jatropha fruits are photosynthetically as efficient as its leaves and play a paramount role in scavenging the high concentration of CO(2) generated by the fruit during respiration. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  4. Culturing photosynthetic bacteria through surface plasmon resonance

    Energy Technology Data Exchange (ETDEWEB)

    Ooms, Matthew D.; Bajin, Lauren; Sinton, David [Department of Mechanical and Industrial Engineering and Centre for Sustainable Energy, University of Toronto, Toronto M5S 3G8 (Canada)

    2012-12-17

    In this work, cultivation of photosynthetic microbes in surface plasmon enhanced evanescent fields is demonstrated. Proliferation of Synechococcus elongatus was obtained on gold surfaces excited with surface plasmons. Excitation over three days resulted in 10 {mu}m thick biofilms with maximum cell volume density of 20% vol/vol (2% more total accumulation than control experiments with direct light). Collectively, these results indicate the ability to (1) excite surface-bound cells using plasmonic light fields, and (2) subsequently grow thick biofilms by coupling light from the surface. Plasmonic light delivery presents opportunities for high-density optofluidic photobioreactors for microalgal analysis and solar fuel production.

  5. Culturing photosynthetic bacteria through surface plasmon resonance

    Science.gov (United States)

    Ooms, Matthew D.; Bajin, Lauren; Sinton, David

    2012-12-01

    In this work, cultivation of photosynthetic microbes in surface plasmon enhanced evanescent fields is demonstrated. Proliferation of Synechococcus elongatus was obtained on gold surfaces excited with surface plasmons. Excitation over three days resulted in 10 μm thick biofilms with maximum cell volume density of 20% vol/vol (2% more total accumulation than control experiments with direct light). Collectively, these results indicate the ability to (1) excite surface-bound cells using plasmonic light fields, and (2) subsequently grow thick biofilms by coupling light from the surface. Plasmonic light delivery presents opportunities for high-density optofluidic photobioreactors for microalgal analysis and solar fuel production.

  6. Engineering cyanobacteria as photosynthetic feedstock factories.

    Science.gov (United States)

    Hays, Stephanie G; Ducat, Daniel C

    2015-03-01

    Carbohydrate feedstocks are at the root of bioindustrial production and are needed in greater quantities than ever due to increased prioritization of renewable fuels with reduced carbon footprints. Cyanobacteria possess a number of features that make them well suited as an alternative feedstock crop in comparison to traditional terrestrial plant species. Recent advances in genetic engineering, as well as promising preliminary investigations of cyanobacteria in a number of distinct production regimes have illustrated the potential of these aquatic phototrophs as biosynthetic chassis. Further improvements in strain productivities and design, along with enhanced understanding of photosynthetic metabolism in cyanobacteria may pave the way to translate cyanobacterial theoretical potential into realized application.

  7. ENHANCED PRACTICAL PHOTOSYNTHETIC CO2 MITIGATION

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Gregory Kremer; Dr. David J. Bayless; Dr. Morgan Vis; Dr. Michael Prudich; Dr. Keith Cooksey; Dr. Jeff Muhs

    2001-10-15

    This report documents significant achievements in the Enhanced Practical Photosynthetic CO{sub 2} Mitigation project during the period from 10/03/2000 through 10/02/2001. Most of the achievements are milestones in our efforts to complete the tasks and subtasks that constitute the project objectives. This is the fourth quarterly report for this project, so it also serves as a year-1 project review. We have made significant progress on our Phase I objectives, and our current efforts are focused on fulfilling these research objectives ''on time'' relative to the project timeline. Overall, we believe that we are on schedule to complete Phase I activities by 10/2002, which is the milestone date from the original project timeline. Our results to date concerning the individual factors which have the most significant effect on CO{sub 2} uptake are inconclusive, but we have gathered useful information about the effects of lighting, temperature and CO{sub 2} concentration on one particular organism (Nostoc) and significant progress has been made in identifying other organisms that are more suitable for use in the bioreactor due to their better tolerance for the high temperatures likely to be encountered in the flue gas stream. Our current tests are focused on one such thermophilic organism (Cyanidium), and an enlarged bioreactor system (CRF-2) has been prepared for testing this organism. Tests on the enhanced mass transfer CO{sub 2} absorption technique are underway and useful information is currently being collected concerning pressure drop. The solar collectors for the deep-penetration hybrid solar lighting system have been designed and a single solar collector tracking unit is being prepared for installation in the pilot scale bioreactor system currently under construction. Much progress has been made in designing the fiber optic light delivery system, but final selection of the ''optimum'' delivery system design depends on many

  8. ENHANCED PRACTICAL PHOTOSYNTHETIC CO2 MITIGATION

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Gregory Kremer; Dr. David J. Bayless; Dr. Morgan Vis; Dr. Michael Prudich; Dr. Keith Cooksey; Dr. Jeff Muhs

    2002-07-15

    This quarterly report documents significant achievements in the Enhanced Practical Photosynthetic CO{sub 2} Mitigation project during the period from 4/2/2001 through 7/01/2002. Most of the achievements are milestones in our efforts to complete the tasks and subtasks that constitute the project objectives, and we are currently on schedule to complete Phase I activities by 10/2002, the milestone date from the original project timeline. As indicated in the list of accomplishments below, our efforts are focused on improving the design of the bioreactor test system, evaluating candidate organisms and growth surfaces, and scaling-up the test facilities from bench scale to pilot scale. Specific results and accomplishments for the second quarter of 2002 include: Organisms and Growth Surfaces: (1) Our collection of cyanobacteria, isolated in YNP was increased to 15 unialgal cultures. (2) Illumination rate about 50 {micro}E/m{sup 2}/sec is not saturated for the growth of 1.2 s.c. (2) isolate. The decrease of illumination rate led to the decrease of doubling time of this isolate. (3) The positive effect of Ca{sup 2+} on the growth of isolate 1.2 s.c. (2) without Omnisil was revealed, though Ca{sup 2+} addition was indifferent for the growth of this isolate at the presence of Omnisil. (4) Calcium addition had a positive effect on the generation of cyanobacterial biofilm on Omnisil surface. (5) The survivability problems with the Tr9.4 organism on Omnisil screens in the CRF2 model-scale bioreactor have been solved. The problems were related to the method used to populate the growth surfaces. When pre-populated screens were placed in the bioreactor the microalgae died within 72 hours, but when the microalgae were cultured while in place in the bioreactor using a continuous-population method they grew well inside of the CRF2 test system and survived for the full 7-day test duration. CRF2 tests will continue as soon as the new combined drip system/harvesting system header pipe

  9. Incidence and trends of infection with pathogens transmitted commonly through food--Foodborne Diseases Active Surveillance Network, 10 U.S. sites, 2006-2013.

    Science.gov (United States)

    Crim, Stacy M; Iwamoto, Martha; Huang, Jennifer Y; Griffin, Patricia M; Gilliss, Debra; Cronquist, Alicia B; Cartter, Matthew; Tobin-D'Angelo, Melissa; Blythe, David; Smith, Kirk; Lathrop, Sarah; Zansky, Shelley; Cieslak, Paul R; Dunn, John; Holt, Kristin G; Lance, Susan; Tauxe, Robert; Henao, Olga L

    2014-04-18

    Foodborne disease continues to be an important problem in the United States. Most illnesses are preventable. To evaluate progress toward prevention, the Foodborne Diseases Active Surveillance Network (FoodNet) monitors the incidence of laboratory-confirmed infections caused by nine pathogens transmitted commonly through food in 10 U.S. sites, covering approximately 15% of the U.S. population. This report summarizes preliminary 2013 data and describes trends since 2006. In 2013, a total of 19,056 infections, 4,200 hospitalizations, and 80 deaths were reported. For most infections, incidence was well above national Healthy People 2020 incidence targets and highest among children aged <5 years. Compared with 2010-2012, the estimated incidence of infection in 2013 was lower for Salmonella, higher for Vibrio, and unchanged overall.† Since 2006-2008, the overall incidence has not changed significantly. More needs to be done. Reducing these infections requires actions targeted to sources and pathogens, such as continued use of Salmonella poultry performance standards and actions mandated by the Food Safety Modernization Act (FSMA). FoodNet provides federal and state public health and regulatory agencies as well as the food industry with important information needed to determine if regulations, guidelines, and safety practices applied across the farm-to-table continuum are working.

  10. Highly predictable photosynthetic production in natural macroalgal communities from incoming and absorbed light

    DEFF Research Database (Denmark)

    Middelboe, Anne Lise; Sand-Jensen, Kaj; Binzer, Thomas

    2006-01-01

    Photosynthesis-irradiance relationships of macroalgal communities and thalli of dominant species in shallow coastal Danish waters were measured over a full year to test how well community production can be predicted from environmental (incident irradiance and temperature) and community variables...... and was unrelated to incident irradiance, temperature and mean thallus photosynthesis, while community absorptance was a highly significant predictor. Actual rates of community photosynthesis were closely related to incident and absorbed irradiance alone. Community absorptance in turn was correlated to canopy...... (canopy absorptance, species number and thallus metabolism). Detached thalli of dominant species performed optimally at different times of the year, but showed no general seasonal changes in photosynthetic features. Production capacity of communities at high light varied only 1.8-fold over the year...

  11. Incidence, clinical presentation, and outcome of HIV-1-associated cryptococcal meningitis during the highly active antiretroviral therapy era: a nationwide cohort study.

    Science.gov (United States)

    Touma, Madeleine; Rasmussen, Line D; Martin-Iguacel, Raquel; Engsig, Frederik Neess; Stærke, Nina Breinholt; Stærkind, Mette; Obel, Niels; Ahlström, Magnus Glindvad

    2017-01-01

    Human immunodeficiency virus (HIV) infection with advanced immunosuppression predisposes to cryptococcal meningitis (CM). We describe the incidence, clinical presentation, and outcome of CM in HIV-infected individuals during the highly active antiretroviral therapy (HAART) era. A nationwide, population-based cohort of HIV-infected individuals was used to estimate incidence and mortality of CM including risk factors. A description of neurological symptoms of CM at presentation and follow-up in the study period 1995-2014 was included in this study. Among 6,351 HIV-infected individuals, 40 were diagnosed with CM. The incidence rates were 3.7, 1.8, and 0.3 per 1000 person-years at risk in 1995-1996, 1997-1999, and 2000-2014, respectively. Initiation of HAART was associated with decreased risk of acquiring CM [incidence rate ratio (IRR), 0.1 (95% CI, 0.05-0.22)]. African origin was associated with increased risk of CM [IRR, 2.05 (95% CI, 1.00-4.20)]. The main signs and symptoms at presentation were headache, cognitive deficits, fever, neck stiffness, nausea, and vomiting. All individuals diagnosed with CM had a CD4 + cell count <200 cells/µl [median 26; interquartile range (IQR), 10-50)]. Overall, mortality following CM was high and mortality in the first 4 months has not changed substantially over time. However, individuals who survived generally had a favorable prognosis, with 86% (18/21) returning to the pre-CM level of activity. The incidence of HIV-associated CM has decreased substantially after the introduction of HAART. To further decrease CM incidence and associated mortality, early HIV diagnosis and HAART initiation seems crucial.

  12. Enhanced photosynthetic capacity and antioxidant potential mediate brassinosteriod-induced phenanthrene stress tolerance in tomato

    International Nuclear Information System (INIS)

    Ahammed, Golam Jalal; Li, Xin; Xia, Xiao-Jian; Shi, Kai; Zhou, Yan-Hong; Yu, Jing-Quan

    2015-01-01

    Photosynthesis, the basal manufacturing process in the earth is habitually restricted by airborne micropollutants such as phenanthrene (PHE). Here, we show that 24-epibrassinolide (EBR), a bioactive plant steroid is able to keep higher photosynthetic capacity consistently for a long period under a shoot-imposed PHE stress in tomato. EBR-promoted photosynthetic capacity and efficiency eventually resulted in a 37.5% increase of biomass under PHE stress. As primary response, transcripts of antioxidant genes were remarkably induced by EBR in PHE-treated plants. Activities of antioxidant and detoxification enzymes were also enhanced by EBR. Notably, EBR-induced higher antioxidant potential was associated with reduced levels of H 2 O 2 and O 2 · — , resulting in a 32.7% decrease of content of malondialdehyde in the end of experiment and relatively healthy chloroplast ultrastructure in EBR + PHE treatment compared with PHE alone. These results indicate that EBR alleviates shoot-imposed PHE phytotoxicity by maintaining a consistently higher photosynthetic capacity and antioxidant potential in tomato. - Highlights: • PHE mist spray gradually inhibits photosynthesis and eventually reduces biomass. • EBR maintains a consistently higher photosynthesis even under PHE stress. • EBR upregulates expression of antioxidant genes as initial response to PHE stress. • EBR reduces oxidative stress by constantly activating strong antioxidant potential. • EBR-induced efficient neutralization of ROS protects chloroplast ultrastructure. - 24-epibrassinolide protects tomato plants from airborne phenanthrene-induced damages by maintaining a consistently higher photosynthetic capacity and antioxidant potential

  13. Redox regulation of photosynthetic gene expression.

    Science.gov (United States)

    Queval, Guillaume; Foyer, Christine H

    2012-12-19

    Redox chemistry and redox regulation are central to the operation of photosynthesis and respiration. However, the roles of different oxidants and antioxidants in the regulation of photosynthetic or respiratory gene expression remain poorly understood. Leaf transcriptome profiles of a range of Arabidopsis thaliana genotypes that are deficient in either hydrogen peroxide processing enzymes or in low molecular weight antioxidant were therefore compared to determine how different antioxidant systems that process hydrogen peroxide influence transcripts encoding proteins targeted to the chloroplasts or mitochondria. Less than 10 per cent overlap was observed in the transcriptome patterns of leaves that are deficient in either photorespiratory (catalase (cat)2) or chloroplastic (thylakoid ascorbate peroxidase (tapx)) hydrogen peroxide processing. Transcripts encoding photosystem II (PSII) repair cycle components were lower in glutathione-deficient leaves, as were the thylakoid NAD(P)H (nicotinamide adenine dinucleotide (phosphate)) dehydrogenases (NDH) mRNAs. Some thylakoid NDH mRNAs were also less abundant in tAPX-deficient and ascorbate-deficient leaves. Transcripts encoding the external and internal respiratory NDHs were increased by low glutathione and low ascorbate. Regulation of transcripts encoding specific components of the photosynthetic and respiratory electron transport chains by hydrogen peroxide, ascorbate and glutathione may serve to balance non-cyclic and cyclic electron flow pathways in relation to oxidant production and reductant availability.

  14. Thermal responses of Symbiodinium photosynthetic carbon assimilation

    Science.gov (United States)

    Oakley, Clinton A.; Schmidt, Gregory W.; Hopkinson, Brian M.

    2014-06-01

    The symbiosis between hermatypic corals and their dinoflagellate endosymbionts, genus Symbiodinium, is based on carbon exchange. This symbiosis is disrupted by thermally induced coral bleaching, a stress response in which the coral host expels its algal symbionts as they become physiologically impaired. The disruption of the dissolved inorganic carbon (DIC) supply or the thermal inactivation of Rubisco have been proposed as sites of initial thermal damage that leads to the bleaching response. Symbiodinium possesses a highly unusual Form II ribulose bisphosphate carboxylase/oxygenase (Rubisco), which exhibits a lower CO2:O2 specificity and may be more thermally unstable than the Form I Rubiscos of other algae and land plants. Components of the CO2 concentrating mechanism (CCM), which supplies inorganic carbon for photosynthesis, may also be temperature sensitive. Here, we examine the ability of four cultured Symbiodinium strains to acquire and fix DIC across a temperature gradient. Surprisingly, the half-saturation constant of photosynthesis with respect to DIC concentration ( K P), an index of CCM function, declined with increasing temperature in three of the four strains, indicating a greater potential for photosynthetic carbon acquisition at elevated temperatures. In the fourth strain, there was no effect of temperature on K P. Finding no evidence for thermal inhibition of the CCM, we conclude that CCM components are not likely to be the primary sites of thermal damage. Reduced photosynthetic quantum yields, a hallmark of thermal bleaching, were observed at low DIC concentrations, leaving open the possibility that reduced inorganic carbon availability is involved in bleaching.

  15. Ecotoxicological studies of CdS nanoparticles on photosynthetic microorganisms.

    Science.gov (United States)

    Brayner, Roberta; Dahoumane, Si Amar; Nguyen, Julie Ngoc-Lan; Yéprémian, Claude; Djediat, Chakib; Couté, Alain; Fiévet, Fernand

    2011-03-01

    The potential ecotoxicity of nanosized cadmium sulfide (CdS), synthesized by the polyol process, was investigated using common Anabaena flos-aquae cyanobacteria and Euglena gracilis euglenoid microalgae. The photosynthetic activities of these microorganisms, after addition of free Cd2+ ions and CdS nanoparticles, varied with the presence of tri-n-octylphosphine oxide (TOPO) used to protect surface particle to avoid toxicity and also to control particle size and shape during the synthesis. The nanoparticle concentration was varied from 10(-3) to 5 x 10(-4) M. It was observed that the cadmium concentration, the addition of TOPO protective agent and the particle dissolution process in the culture medium play an important role during the ecotoxicological tests. Viability tests were followed by PAM fluorimetry. Cd2+ ions were very toxic for Anabaena flos aquae. The same behavior was observed after contact with CdS and CdS-TOPO nanoparticles. However, for Euglena gracilis, the photosynthetic activity was stable for more than 1 month in the presence of Cd2+ ions. Moreover, it was observed that the toxicity varies with the concentration of CdS and CdS-TOPO nanoparticles, both kind of nanoparticles are toxic for this microorganism. Transmission electron microscopy (TEM) analyses of microorganisms ultrathin sections showed that polysaccharides produced by Anabaena flos-aquae, after contact with CdS and CdS-TOPO nanoparticles, protect the microalgae against particle internalization. Only some particles were observed inside the cells. Moreover, the nanoparticle internalization was observed after contact with all nanoparticles in the presence of Euglena gracilis by endocytosis. All nanoparticles are inside vesicles formed by the cells.

  16. Incidents analysis

    International Nuclear Information System (INIS)

    Francois, P.

    1996-01-01

    We undertook a study programme at the end of 1991. To start with, we performed some exploratory studies aimed at learning some preliminary lessons on this type of analysis: Assessment of the interest of probabilistic incident analysis; possibility of using PSA scenarios; skills and resources required. At the same time, EPN created a working group whose assignment was to define a new approach for analysis of incidents on NPPs. This working group gave thought to both aspects of Operating Feedback that EPN wished to improve: Analysis of significant incidents; analysis of potential consequences. We took part in the work of this group, and for the second aspects, we proposed a method based on an adaptation of the event-tree method in order to establish a link between existing PSA models and actual incidents. Since PSA provides an exhaustive database of accident scenarios applicable to the two most common types of units in France, they are obviously of interest for this sort of analysis. With this method we performed some incident analyses, and at the same time explores some methods employed abroad, particularly ASP (Accident Sequence Precursor, a method used by the NRC). Early in 1994 EDF began a systematic analysis programme. The first, transient phase will set up methods and an organizational structure. 7 figs

  17. Incidences of Unfavorable Events in the Management of Low-Risk Papillary Microcarcinoma of the Thyroid by Active Surveillance Versus Immediate Surgery.

    Science.gov (United States)

    Oda, Hitomi; Miyauchi, Akira; Ito, Yasuhiro; Yoshioka, Kana; Nakayama, Ayako; Sasai, Hisanori; Masuoka, Hiroo; Yabuta, Tomonori; Fukushima, Mitsuhiro; Higashiyama, Takuya; Kihara, Minoru; Kobayashi, Kaoru; Miya, Akihiro

    2016-01-01

    The incidence of papillary microcarcinoma (PMC) of the thyroid is rapidly increasing globally, making the management of PMC an important clinical issue. Excellent oncological outcomes of active surveillance for low-risk PMC have been reported previously. Here, unfavorable events following active surveillance and surgical treatment for PMC were studied. From February 2005 to August 2013, 2153 patients were diagnosed with low-risk PMC. Of these, 1179 patients chose active surveillance and 974 patients chose immediate surgery. The oncological outcomes and the incidences of unfavorable events of these groups were analyzed. In the active surveillance group, 94 patients underwent surgery for various reasons; tumor enlargement and the appearance of novel lymph node metastases were the reasons in 27 (2.3%) and six patients (0.5%), respectively. One of the patients with conversion to surgery had nodal recurrence, and five patients in the immediate surgery group had a recurrence in a cervical node or unresected thyroid lobe. All of these recurrences were successfully treated. None of the patients had distant metastases, and none died of the disease. The immediate surgery group had significantly higher incidences of transient vocal cord paralysis (VCP), transient hypoparathyroidism, and permanent hypoparathyroidism than the active-surveillance group did (4.1% vs. 0.6%, p < 0.0001; 16.7% vs. 2.8%, p < 0.0001; and 1.6% vs. 0.08%, p < 0.0001, respectively). Permanent VCP occurred only in two patients (0.2%) in the immediate surgery group. The proportion of patients on L-thyroxine for supplemental or thyrotropin (TSH)-suppressive purposes was significantly larger in the immediate surgery group than in the active surveillance group (66.1% vs. 20.7%, p < 0.0001). The immediate surgery group had significantly higher incidences of postsurgical hematoma and surgical scar in the neck compared with the active surveillance group (0.5% vs. 0%, p < 0.05; and 8.0% vs

  18. Interfacing Photosynthetic Membrane Protein with Mesoporous WO3 Photoelectrode for Solar Water Oxidation.

    Science.gov (United States)

    Pang, Hong; Zhao, Guixia; Liu, Guigao; Zhang, Huabin; Hai, Xiao; Wang, Shengyao; Song, Hui; Ye, Jinhua

    2018-04-10

    Photosynthetic biocatalysts are emerging as a new class of materials, with their sophisticated and intricate structure, which promise improved remarkable quantum efficiency compared to conventional inorganic materials in artificial photosynthesis. To break the limitation of efficiency, the construction of bioconjugated photo-electrochemical conversion devices has garnered substantial interest and stood at the frontier of the multidisciplinary research between biology and chemistry. Herein, a biohybrid photoanode of a photosynthetic membrane protein (Photosystem II (PS II)), extracted from fresh spinach entrapped on mesoporous WO 3 film, is fabricated on fluorine-doped tin oxide. The PS II membrane proteins are observed to communicate with the WO 3 electrode in the absence of any soluble redox mediators and sacrificial reagents under the visible light of the solar spectrum, even to 700 nm. The biohybrid electrode undergoes electron transfer and generates a significantly enhanced photocurrent compared to previously reported PS II-based photoanodes with carbon nanostructures or other semiconductor substrates for solar water oxidation. The maximum incident photon-to-current conversion efficiency reaches 15.24% at 400 nm in the visible light region. This work provides some insights and possibilities into the efficient assembly of a future solar energy conversion system based on visible-light-responsive semiconductors and photosynthetic proteins. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Influence of physical activity, sedentary behavior, and diet quality in childhood on the incidence of internalizing and externalizing disorders during adolescence: a population-based cohort study.

    Science.gov (United States)

    Wu, XiuYun; Bastian, Kerry; Ohinmaa, Arto; Veugelers, Paul

    2018-02-01

    Studies among youth suggest that physical inactivity, sedentary behaviors, and poor diet quality are associated with poor mental health. Few population-based studies have investigated these relationships longitudinally. We examined the association between physical activity, sedentary behaviors, and diet quality in childhood and the incidence of internalizing and externalizing disorders throughout adolescence. We linked health behavior survey data from 2003 among 10- to 11-year-old children across Nova Scotia, Canada, with administrative health care data from 2003 to 2011. Students' diet quality was assessed using the Harvard Food Frequency Questionnaire. Physical activity and sedentary behaviors were self-reported, and internalizing and externalizing disorders were diagnosed by a physician. We applied Cox regression to examine the associations of the health behaviors with the incidence of internalizing and externalizing disorders between 2003 and 2011. Of the 4861 participating students, 23.7% and 9.4% had a diagnosis of internalizing and externalizing disorders, respectively. The incidences of internalizing and externalizing disorders were higher among students who were less physically active and spent more time using computers and video games. These findings suggest that promoting an active lifestyle in childhood may contribute to the prevention of both internalizing and externalizing disorders during adolescence. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Incidence and outcomes of dystocia in the active phase of labor in term nulliparous women with spontaneous labor onset

    DEFF Research Database (Denmark)

    Kjaergaard, Hanne; Olsen, Jørn; Ottesen, Bent

    2009-01-01

    -clear amniotic fluid, more post-partum hemorrhage and their children were more often given low one-minute neonatal Apgar scores as compared to women delivered without a diagnosis of dystocia. CONCLUSIONS: A dystocia incidence of 37% was found in healthy term nulliparas with no indication for induction...

  1. Photosynthetic performance of Arctic macroalgae after transplantation from deep to shallow waters.

    Science.gov (United States)

    Karsten, U; Bischof, K; Wiencke, C

    2001-03-01

    Transplantation experiments conducted in the Arctic Kongsfjord (Spitsbergen) in summer 1997 investigated the effects of various types of filtered natural radiation (solar, solar without UV-B, solar without UV-A/B) on photosynthesis of various macroalgae. Two brown algal species (Laminaria solidungula, Saccorhiza dermatodea) and four red algal species (Palmaria palmata, Phycodrys rubens, Phyllophora truncata, Ptilota plumosa) were collected from deeper waters, kept in UV-transparent plexiglass tubes wrapped with different spectral cut-off filter foils and positioned at fixed depths in shallow waters for 7-9 days. At regular intervals, chlorophyll fluorescence of photosystem II (optimum quantum yield, F v /F m ) was determined, as an indicator of photosynthetic performance. The data demonstrate that shallow-water species such as P. palmata are much less affected by natural photosynthetically active radiation (PAR) and UV radiation near the surface than extremely sensitive deep-water species such as Phyc. rubens which exhibited strong decreases in photosynthetic performance, as well as photobleaching of part of the thallus. The other species showed intermediate response patterns. In most species investigated inhibition of photosynthesis was mainly caused by the UV-B wavelengths. Interpretation of the data clearly indicates species-specific tolerances of photosynthesis to ambient solar radiation which can be explained by broad physiological acclimation potentials and/or genetic adaptation to certain (low or high) irradiances. The species-specific photosynthetic performance under radiation stress is in good accordance with the vertical distribution of the macroalgae on the shore.

  2. Ocean acidification alters the photosynthetic responses of a coccolithophorid to fluctuating ultraviolet and visible radiation.

    Science.gov (United States)

    Jin, Peng; Gao, Kunshan; Villafañe, Virginia E; Campbell, Douglas A; Helbling, E Walter

    2013-08-01

    Mixing of seawater subjects phytoplankton to fluctuations in photosynthetically active radiation (400-700 nm) and ultraviolet radiation (UVR; 280-400 nm). These irradiance fluctuations are now superimposed upon ocean acidification and thinning of the upper mixing layer through stratification, which alters mixing regimes. Therefore, we examined the photosynthetic carbon fixation and photochemical performance of a coccolithophore, Gephyrocapsa oceanica, grown under high, future (1,000 μatm) and low, current (390 μatm) CO₂ levels, under regimes of fluctuating irradiances with or without UVR. Under both CO₂ levels, fluctuating irradiances, as compared with constant irradiance, led to lower nonphotochemical quenching and less UVR-induced inhibition of carbon fixation and photosystem II electron transport. The cells grown under high CO₂ showed a lower photosynthetic carbon fixation rate but lower nonphotochemical quenching and less ultraviolet B (280-315 nm)-induced inhibition. Ultraviolet A (315-400 nm) led to less enhancement of the photosynthetic carbon fixation in the high-CO₂-grown cells under fluctuating irradiance. Our data suggest that ocean acidification and fast mixing or fluctuation of solar radiation will act synergistically to lower carbon fixation by G. oceanica, although ocean acidification may decrease ultraviolet B-related photochemical inhibition.

  3. Ethylene potentiates sulfur-mediated reversal of cadmium inhibited photosynthetic responses in mustard

    Directory of Open Access Journals (Sweden)

    Nafees A Khan

    2016-11-01

    Full Text Available The potential of exogenous ethylene and sulfur (S in reversal of cadmium (Cd-inhibited photosynthetic and growth responses in mustard (Brassica juncea L. cv. Pusa Jai Kisan were studied. Plants grown with 50 µM Cd showed increased superoxide and H2O2 accumulation and lipid peroxidation together with increased activity of 1-aminocyclopropane carboxylic acid synthase (ACS and ethylene production and inhibition of photosynthesis and growth. Application of 1 mM SO42− or 200 µL L−1 ethephon (ethylene source influenced photosynthetic and growth performance equally in presence or absence of Cd. However, their combined application synergistically improved photosynthetic performance more in presence of Cd and reduced oxidative stress (lower superoxide and H2O2 accumulation by decreasing ethylene and glucose sensitivity with the increase in cysteine and methionineand a non-proteinogenic thiol (reduced glutathione; GSH contents. The central role of ethylene in potentiating S-mediated reversal of Cd-induced oxidative stress was evident with the use ethylene action inhibitor, norbornadiene (NBD. The application of NBD resulted in decreased thiol production and photosynthetic responses. This suggests that ethylene promotes the effects of S in reversal of adverse effects of Cd, and thus, ethylene modulation may be considered as potential tool to substantiate the S effects in reversal of Cd inhibited photosynthesis and growth in mustard.

  4. Mitochondria Affect Photosynthetic Electron Transport and Photosensitivity in a Green Alga.

    Science.gov (United States)

    Larosa, Véronique; Meneghesso, Andrea; La Rocca, Nicoletta; Steinbeck, Janina; Hippler, Michael; Szabò, Ildikò; Morosinotto, Tomas

    2018-03-01

    Photosynthetic organisms use sunlight as the primary source of energy to support their metabolism. In eukaryotes, reactions responsible of the conversion of light into chemical energy occur in specific organelles, the chloroplasts. In this study, we showed that mitochondria also have a seminal influence on cells' energy metabolism and on photosynthetic reactions. This is illustrated by the observation that the strong photosensitivity of Chlamydomonas reinhardtii cells depleted of the chloroplast protein PGRL1 was rescued by the introduction of a mitochondrial mutation affecting respiratory complex I. Functional analysis showed that such a reduced respiratory activity influenced chloroplast electron transport with consequent overreduction of plastoquinone and donor-side limitation of photosystem I (PSI). As a consequence, damage due to excess light affected more photosystem II (PSII) rather than PSI. Double mutant cells are able to grow under excess illumination, while single pgrl1 are not, thanks to the presence of an efficient repair mechanism of PSII. These results also underline the seminal biological relevance of the regulation of electron transport reactions within the photosynthetic complexes. Photosynthetic organisms evolved a strategy to respond to excess light where damage is targeting preferentially to a specific complex, PSII. Cells are able to endure extensive damage targeting this complex thanks to an efficient repair mechanisms, while if PSI is affected, there are drastic consequences on growth. © 2018 American Society of Plant Biologists. All Rights Reserved.

  5. Abiotic Stresses: Insight into Gene Regulation and Protein Expression in Photosynthetic Pathways of Plants

    Science.gov (United States)

    Nouri, Mohammad-Zaman; Moumeni, Ali; Komatsu, Setsuko

    2015-01-01

    Global warming and climate change intensified the occurrence and severity of abiotic stresses that seriously affect the growth and development of plants, especially, plant photosynthesis. The direct impact of abiotic stress on the activity of photosynthesis is disruption of all photosynthesis components such as photosystem I and II, electron transport, carbon fixation, ATP generating system and stomatal conductance. The photosynthetic system of plants reacts to the stress differently, according to the plant type, photosynthetic systems (C3 or C4), type of the stress, time and duration of the occurrence and several other factors. The plant responds to the stresses by a coordinate chloroplast and nuclear gene expression. Chloroplast, thylakoid membrane, and nucleus are the main targets of regulated proteins and metabolites associated with photosynthetic pathways. Rapid responses of plant cell metabolism and adaptation to photosynthetic machinery are key factors for survival of plants in a fluctuating environment. This review gives a comprehensive view of photosynthesis-related alterations at the gene and protein levels for plant adaptation or reaction in response to abiotic stress. PMID:26343644

  6. Redox-state dynamics of ubiquinone-10 imply cooperative regulation of photosynthetic membrane expression in Rhodospirillum rubrum.

    Science.gov (United States)

    Grammel, Hartmut; Ghosh, Robin

    2008-07-01

    It is now well established that, for photosynthetic bacteria, the aerobic-to-microaerophilic transition activates the membrane-bound sensor kinase RegB, which subsequently phosphorylates the transcriptional activator RegA, thereby inducing elevated levels of intracellular photosynthetic membranes. The mechanism of RegB activation--in particular, the role of ubiquinone-10--is controversial at present. One problem here is that very limited quantitative in vivo data for the response of the ubiquinone redox state to different cultivation conditions exist. Here, we utilize Rhodospirillum rubrum to study the correlation of the quinone redox state to the expression level of photosynthetic membranes and determine an effective response function directly. Our results show that changes in the photosynthetic membrane levels between 50 and 95% of that maximally attainable are associated with only a twofold change in the ubiquinol/ubiquinone ratio and are not necessarily proportional to the total levels of either quinone or [NAD(+) + NADH]. There is no correlation between the redox potentials of the quinone and pyridine nucleotide pools. Hill function analysis of the photosynthetic membrane induction in response to the quinone redox state suggests that the induction process is highly cooperative. Our results are probably generally applicable to quinone redox regulation in bacteria.

  7. Variations in morphology and PSII photosynthetic capabilities during the early development of tetraspores of Gracilaria vermiculophylla (Ohmi) Papenfuss (Gracilariales, Rhodophyta).

    Science.gov (United States)

    Xie, Xiujun; Wang, Guangce; Pan, Guanghua; Gao, Shan; Xu, Pu; Zhu, Jianyi

    2010-04-28

    Red algae are primitive photosynthetic eukaryotes, whose spores are ideal subjects for studies of photosynthesis and development. Although the development of red alga spores has received considerable research attention, few studies have focused on the detailed morphological and photosynthetic changes that occur during the early development of tetraspores of Gracilaria vermiculophylla (Ohmi) Papenfuss (Gracilariales, Rhodophyta). Herein, we documented these changes in this species of red algae. In the tetraspores, we observed two types of division, cruciate and zonate, and both could develop into multicellular bodies (disks). During the first 84 hours, tetraspores divided several times, but the diameter of the disks changed very little; thereafter, the diameter increased significantly. Scanning electron microscopy observations and analysis of histological sections revealed that the natural shape of the disk remains tapered over time, and the erect frond grows from the central protrusion of the disk. Cultivation of tissue from excised disks demonstrated that the central protrusion of the disk is essential for initiation of the erect frond. Photosynthetic (i.e., PSII) activities were measured using chlorophyll fluorescence analysis. The results indicated that freshly released tetraspores retained limited PSII photosynthetic capabilities; when the tetraspores attached to a substrate, those capabilities increased significantly. In the disk, the PSII activity of both marginal and central cells was similar, although some degree of morphological polarity was present; the PSII photosynthetic capabilities in young germling exhibited an apico-basal gradient. Attachment of tetraspores to a substrate significantly enhanced their PSII photosynthetic capabilities, and triggered further development. The central protrusion of the disk is the growth point, may have transfer of nutritive material with the marginal cells. Within the young germling, the hetero-distribution of PSII

  8. Variations in morphology and PSII photosynthetic capabilities during the early development of tetraspores of Gracilaria vermiculophylla (Ohmi Papenfuss (Gracilariales, Rhodophyta

    Directory of Open Access Journals (Sweden)

    Gao Shan

    2010-04-01

    Full Text Available Abstract Background Red algae are primitive photosynthetic eukaryotes, whose spores are ideal subjects for studies of photosynthesis and development. Although the development of red alga spores has received considerable research attention, few studies have focused on the detailed morphological and photosynthetic changes that occur during the early development of tetraspores of Gracilaria vermiculophylla (Ohmi Papenfuss (Gracilariales, Rhodophyta. Herein, we documented these changes in this species of red algae. Results In the tetraspores, we observed two types of division, cruciate and zonate, and both could develop into multicellular bodies (disks. During the first 84 hours, tetraspores divided several times, but the diameter of the disks changed very little; thereafter, the diameter increased significantly. Scanning electron microscopy observations and analysis of histological sections revealed that the natural shape of the disk remains tapered over time, and the erect frond grows from the central protrusion of the disk. Cultivation of tissue from excised disks demonstrated that the central protrusion of the disk is essential for initiation of the erect frond. Photosynthetic (i.e., PSII activities were measured using chlorophyll fluorescence analysis. The results indicated that freshly released tetraspores retained limited PSII photosynthetic capabilities; when the tetraspores attached to a substrate, those capabilities increased significantly. In the disk, the PSII activity of both marginal and central cells was similar, although some degree of morphological polarity was present; the PSII photosynthetic capabilities in young germling exhibited an apico-basal gradient. Conclusions Attachment of tetraspores to a substrate significantly enhanced their PSII photosynthetic capabilities, and triggered further development. The central protrusion of the disk is the growth point, may have transfer of nutritive material with the marginal cells. Within

  9. Incidence and effects of Varicella Zoster Virus infection on academic activities of medical undergraduates--a five-year follow-up study from Sri Lanka.

    Science.gov (United States)

    Agampodi, Suneth B; Dharmaratne, Samath D; Thevanesam, Vasanthi; Dassanayake, Sameera; Kumarihamy, Prabhashini; Ratnayake, Ashani

    2010-05-14

    The adult population in Sri Lanka is having high level of susceptibility for Varicella Zoster Virus (VZV) infection. Among medical undergraduates, 47% are VZV seronegative. The purpose of the present study was to determine the incidence of VZV infection in medical undergraduates in Sri Lanka, and to describe the effects of VZV infection on their academic activities. A retrospective cohort of medical undergraduates' susceptible for VZV infection was selected from the University of Peradeniya, Sri Lanka. Data on the incidence of VZV infection (Chickenpox) during their undergraduate period was collected using a self-administered structured questionnaire. A second questionnaire was administered to collect data on the details of VZV infection and the impact of it on their academic activities. VZV incidence rate was calculated as the number of infections per 1,000 person years of exposure. Descriptive statistics were used to describe the impact of VZV infection on academic activities. Out of the 172 susceptible cohort, 153 medical undergraduates were followed up. 47 students reported VZV infection during the follow up period and 43 of them participated in the study. The cumulative incidence of VZV infection during the period of five and half years of medical training was 30.7%. Incidence density of VZV infection among medical undergraduates in this cohort was 65.1 per 1,000 person years of follow-up. A total of 377 working days were lost by 43 students due to the VZV infection, averaging 8.8 days per undergraduate. Total academic losses for the study cohort were; 205 lectures, 17 practicals, 13 dissection sessions, 11 tutorials, 124 days of clinical training and 107 days of professorial clinical appointments. According to their perception they lost 1,927 study hours due to the illness (Median 50 hours per undergraduate). The incidence of VZV infection among Sri Lankan medical undergraduates is very high and the impact of this infection on academic activities causes

  10. Incidence and effects of Varicella Zoster Virus infection on academic activities of medical undergraduates - a five-year follow-up study from Sri Lanka

    Science.gov (United States)

    2010-01-01

    Background The adult population in Sri Lanka is having high level of susceptibility for Varicella Zoster Virus (VZV) infection. Among medical undergraduates, 47% are VZV seronegative. The purpose of the present study was to determine the incidence of VZV infection in medical undergraduates in Sri Lanka, and to describe the effects of VZV infection on their academic activities. Methods A retrospective cohort of medical undergraduates' susceptible for VZV infection was selected from the University of Peradeniya, Sri Lanka. Data on the incidence of VZV infection (Chickenpox) during their undergraduate period was collected using a self-administered structured questionnaire. A second questionnaire was administered to collect data on the details of VZV infection and the impact of it on their academic activities. VZV incidence rate was calculated as the number of infections per 1,000 person years of exposure. Descriptive statistics were used to describe the impact of VZV infection on academic activities. Results Out of the 172 susceptible cohort, 153 medical undergraduates were followed up. 47 students reported VZV infection during the follow up period and 43 of them participated in the study. The cumulative incidence of VZV infection during the period of five and half years of medical training was 30.7%. Incidence density of VZV infection among medical undergraduates in this cohort was 65.1 per 1,000 person years of follow-up. A total of 377 working days were lost by 43 students due to the VZV infection, averaging 8.8 days per undergraduate. Total academic losses for the study cohort were; 205 lectures, 17 practicals, 13 dissection sessions, 11 tutorials, 124 days of clinical training and 107 days of professorial clinical appointments. According to their perception they lost 1,927 study hours due to the illness (Median 50 hours per undergraduate). Conclusions The incidence of VZV infection among Sri Lankan medical undergraduates is very high and the impact of this

  11. Engineering C4 photosynthetic regulatory networks.

    Science.gov (United States)

    Weissmann, Sarit; Brutnell, Thomas P

    2012-06-01

    C4 photosynthesis is a complex metabolic pathway responsible for carbon fixation in major feed, food and bioenergy crops. Although many enzymes driving this pathway have been identified, regulatory mechanisms underlying this system remain elusive. C4 photosynthesis contributes to photosynthetic efficiency in major bioenergy crops such as sugarcane, Miscanthus, switchgrass, maize and sorghum, and international efforts are underway to engineer C4 photosynthesis into C3 crops. A fundamental understanding of the C4 network is thus needed. New experimental and informatics methods can facilitate the accumulation and analysis of high-throughput data to define components of the C4 system. The use of new model plants, closely related to C4 crops, will also contribute to our understanding of the mechanisms that regulate this complex and important pathway. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Structural basis of photosynthetic water-splitting

    International Nuclear Information System (INIS)

    Photosynthetic water-splitting takes place in photosystem II (PSII), a membrane protein complex consisting of 20 subunits with an overall molecular mass of 350 kDa. The light-induced water-splitting reaction catalyzed by PSII not only converts light energy into biologically useful chemical energy, but also provides us with oxygen indispensible for sustaining oxygenic life on the earth. We have solved the structure of PSII at a 1.9 Å resolution, from which, the detailed structure of the Mn 4 CaO 5 -cluster, the catalytic center for water-splitting, became clear. Based on the structure of PSII at the atomic resolution, possible mechanism of light-induced water-splitting was discussed

  13. Optimal number of pigments in photosynthetic complexes

    International Nuclear Information System (INIS)

    Jesenko, Simon; Žnidarič, Marko

    2012-01-01

    We study excitation energy transfer in a simple model of a photosynthetic complex. The model, described by the Lindblad equation, consists of pigments interacting via dipole–dipole interaction. The overlapping of pigments induces an on-site energy disorder, providing a mechanism for blocking the excitation transfer. Based on the average efficiency as well as the robustness of random configurations of pigments, we calculate the optimal number of pigments that should be enclosed in a pigment–protein complex of a given size. The results suggest that a large fraction of pigment configurations are efficient as well as robust if the number of pigments is properly chosen. We compare the optimal results of the model to the structure of pigment–protein complexes as found in nature, finding good agreement. (paper)

  14. Diversity and abundance of photosynthetic sponges in temperate Western Australia

    Directory of Open Access Journals (Sweden)

    Brümmer Franz

    2009-02-01

    Full Text Available Abstract Background Photosynthetic sponges are important components of reef ecosystems around the world, but are poorly understood. It is often assumed that temperate regions have low diversity and abundance of photosynthetic sponges, but to date no studies have investigated this question. The aim of this study was to compare the percentages of photosynthetic sponges in temperate Western Australia (WA with previously published data on tropical regions, and to determine the abundance and diversity of these associations in a range of temperate environments. Results We sampled sponges on 5 m belt transects to determine the percentage of photosynthetic sponges and identified at least one representative of each group of symbionts using 16S rDNA sequencing together with microscopy techniques. Our results demonstrate that photosynthetic sponges are abundant in temperate WA, with an average of 63% of sponge individuals hosting high levels of photosynthetic symbionts and 11% with low to medium levels. These percentages of photosynthetic sponges are comparable to those found on tropical reefs and may have important implications for ecosystem function on temperate reefs in other areas of the world. A diverse range of symbionts sometimes occurred within a small geographic area, including the three "big" cyanobacterial clades, Oscillatoria spongeliae, "Candidatus Synechococcus spongiarum" and Synechocystis species, and it appears that these clades all occur in a wide range of sponges. Additionally, spongin-permeating red algae occurred in at least 7 sponge species. This study provides the first investigation of the molecular phylogeny of rhodophyte symbionts in sponges. Conclusion Photosynthetic sponges are abundant and diverse in temperate WA, with comparable percentages of photosynthetic to non-photosynthetic sponges to tropical zones. It appears that there are three common generalist clades of cyanobacterial symbionts of sponges which occur in a wide

  15. Mapping the spectral variability in photosynthetic and non-photosynthetic vegetation, soils, and shade using AVIRIS

    Science.gov (United States)

    Roberts, Dar A.; Smith, Milton O.; Sabol, Donald E.; Adams, John B.; Ustin, Susan L.

    1992-01-01

    The primary objective of this research was to map as many spectrally distinct types of green vegetation (GV), non-photosynthetic vegetation (NPV), shade, and soil (endmembers) in an Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) scene as is warranted by the spectral variability of the data. Once determined, a secondary objective was to interpret these endmembers and their abundances spatially and spectrally in an ecological context.

  16. Proton-Coupled Electron Transfer in Artificial Photosynthetic Systems.

    Science.gov (United States)

    Mora, S Jimena; Odella, Emmanuel; Moore, Gary F; Gust, Devens; Moore, Thomas A; Moore, Ana L

    2018-02-20

    protons over ∼7 Å via a Grotthuss-type mechanism, where the protons traverse a network of internally H-bonded sites. In the case of the E2TP process involving BIP analogues with amino group substituents, the thermodynamic price paid in redox potential to move a proton to the final proton acceptor is ∼300 mV. In this example, the decrease in redox potential limits the oxidizing power of the resulting phenoxyl radical. Thus, unlike the biological counterpart, the artificial construct is thermodynamically incapable of effectively advancing the redox state of a water oxidation catalyst. The design of systems where multiple proton transfer events are coupled to an oxidation reaction while a relatively high redox potential is maintained remains an outstanding challenge. The ability to control proton transfer and activity at defined distances and times is key to achieving proton management in the vicinity of catalysts operating at low overpotential in myriad biochemically important processes. Artificial photosynthetic constructs with well-defined structures, such as the ones described in this Account, can provide the means for discovering design principles upon which efficient redox catalysts for electrolysis and fuel cells can be based.

  17. Incidence, clinical presentation, and outcome of HIV-1-associated cryptococcal meningitis during the highly active antiretroviral therapy era: a nationwide cohort study

    Directory of Open Access Journals (Sweden)

    Touma M

    2017-07-01

    Full Text Available Madeleine Touma,1 Line D Rasmussen,2 Raquel Martin-Iguacel,2 Frederik Neess Engsig,3 Nina Breinholt Stærke,4 Mette Stærkind,5 Niels Obel,1 Magnus Glindvad Ahlström1 1Department of Infectious Diseases, Rigshospitalet, Copenhagen University Hospital, Copenhagen, 2Department of Infectious Diseases, Odense University Hospital, Odense, 3Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, 4Department of Infectious Diseases, Aarhus University Hospital, Aarhus, 5Department of Infectious Diseases, Aalborg University Hospital, Aalborg, Denmark Background: Human immunodeficiency virus (HIV infection with advanced immunosuppression predisposes to cryptococcal meningitis (CM. We describe the incidence, clinical presentation, and outcome of CM in HIV-infected individuals during the highly active antiretroviral therapy (HAART era.Methods: A nationwide, population-based cohort of HIV-infected individuals was used to estimate incidence and mortality of CM including risk factors. A description of neurological symptoms of CM at presentation and follow-up in the study period 1995–2014 was included in this study.Results: Among 6,351 HIV-infected individuals, 40 were diagnosed with CM. The incidence rates were 3.7, 1.8, and 0.3 per 1000 person-years at risk in 1995–1996, 1997–1999, and 2000–2014, respectively. Initiation of HAART was associated with decreased risk of acquiring CM [incidence rate ratio (IRR, 0.1 (95% CI, 0.05–0.22]. African origin was associated with increased risk of CM [IRR, 2.05 (95% CI, 1.00–4.20]. The main signs and symptoms at presentation were headache, cognitive deficits, fever, neck stiffness, nausea, and vomiting. All individuals diagnosed with CM had a CD4+ cell count <200 cells/µl [median 26; interquartile range (IQR, 10–50]. Overall, mortality following CM was high and mortality in the first 4 months has not changed substantially over time. However, individuals who survived generally had a

  18. The prevalence and incidence of active syphilis in women in Morocco, 1995-2016: Model-based estimation and implications for STI surveillance.

    Science.gov (United States)

    Bennani, Aziza; El-Kettani, Amina; Hançali, Amina; El-Rhilani, Houssine; Alami, Kamal; Youbi, Mohamed; Rowley, Jane; Abu-Raddad, Laith; Smolak, Alex; Taylor, Melanie; Mahiané, Guy; Stover, John; Korenromp, Eline L

    2017-01-01

    Evolving health priorities and resource constraints mean that countries require data on trends in sexually transmitted infections (STI) burden, to inform program planning and resource allocation. We applied the Spectrum STI estimation tool to estimate the prevalence and incidence of active syphilis in adult women in Morocco over 1995 to 2016. The results from the analysis are being used to inform Morocco's national HIV/STI strategy, target setting and program evaluation. Syphilis prevalence levels and trends were fitted through logistic regression to data from surveys in antenatal clinics, women attending family planning clinics and other general adult populations, as available post-1995. Prevalence data were adjusted for diagnostic test performance, and for the contribution of higher-risk populations not sampled in surveys. Incidence was inferred from prevalence by adjusting for the average duration of infection with active syphilis. In 2016, active syphilis prevalence was estimated to be 0.56% in women 15 to 49 years of age (95% confidence interval, CI: 0.3%-1.0%), and around 21,675 (10,612-37,198) new syphilis infections have occurred. The analysis shows a steady decline in prevalence from 1995, when the prevalence was estimated to be 1.8% (1.0-3.5%). The decline was consistent with decreasing prevalences observed in TB patients, fishermen and prisoners followed over 2000-2012 through sentinel surveillance, and with a decline since 2003 in national HIV incidence estimated earlier through independent modelling. Periodic population-based surveys allowed Morocco to estimate syphilis prevalence and incidence trends. This first-ever undertaking engaged and focused national stakeholders, and confirmed the still considerable syphilis burden. The latest survey was done in 2012 and so the trends are relatively uncertain after 2012. From 2017 Morocco plans to implement a system to record data from routine antenatal programmatic screening, which should help update and re

  19. Prospective epidemiological cohort study of reduced risk for incident cataract with vigorous physical activity and cardiorespiratory fitness during a 7-year follow-up.

    Science.gov (United States)

    Williams, Paul T

    2009-01-01

    To test whether greater vigorous physical activity (kilometers per week run) and greater cardiorespiratory fitness (10-km race performance in meters per second) reduce the incidence of clinically diagnosed cataract. Prospective cohort study of self-reported clinical diagnosis of cataract in nondiabetic, nonvegetarian, and nonsmoking male (n = 29,025) and female runners (n = 11,967). Incident cataracts were reported by 733 (2.53%) men and 179 (1.50%) women during (mean +/- SE) 7.74 +/- 0.01 and 7.42 +/- 0.02 years of follow-up, respectively. The risk for incident cataract increased with BMI, such that the risk in men > 27.5 kg/m(2) was 88% larger than in men Men's cataract risk declined significantly in relation to running distance (P = 0.01), even when adjusted for BMI. Men who ran > or = 64 km/wk had 35% lower risk for cataract than those reporting men with greater cardiorespiratory fitness were at significantly less risk for development of cataract than were the least fit men. This result was not accounted for by adjustment for running distance or BMI. Compared with the least fit men, those who ran faster than 4.75 m/s had 50% lower risk for incident cataract (43% lower when adjusted for km/wk and BMI). These data suggest that the men's cataract risk decreased in association with lower BMI, greater physical activity, and greater cardiorespiratory fitness, the latter being statistically independent of both BMI and physical activity. The study limitations include the absence of confirmation of the clinical diagnosis and the lack of specificity of the type of cataract.

  20. Sustained photosynthetic performance of Coffea spp. under long-term enhanced [CO2].

    Science.gov (United States)

    Ramalho, José C; Rodrigues, Ana P; Semedo, José N; Pais, Isabel P; Martins, Lima D; Simões-Costa, Maria C; Leitão, António E; Fortunato, Ana S; Batista-Santos, Paula; Palos, Isabel M; Tomaz, Marcelo A; Scotti-Campos, Paula; Lidon, Fernando C; DaMatta, Fábio M

    2013-01-01

    Coffee is one of the world's most traded agricultural products. Modeling studies have predicted that climate change will have a strong impact on the suitability of current cultivation areas, but these studies have not anticipated possible mitigating effects of the elevated atmospheric [CO2] because no information exists for the coffee plant. Potted plants from two genotypes of Coffea arabica and one of C. canephora were grown under controlled conditions of irradiance (800 μmol m(-2) s(-1)), RH (75%) and 380 or 700 μL CO2 L(-1) for 1 year, without water, nutrient or root development restrictions. In all genotypes, the high [CO2] treatment promoted opposite trends for stomatal density and size, which decreased and increased, respectively. Regardless of the genotype or the growth [CO2], the net rate of CO2 assimilation increased (34-49%) when measured at 700 than at 380 μL CO2 L(-1). This result, together with the almost unchanged stomatal conductance, led to an instantaneous water use efficiency increase. The results also showed a reinforcement of photosynthetic (and respiratory) components, namely thylakoid electron transport and the activities of RuBisCo, ribulose 5-phosphate kinase, malate dehydrogenase and pyruvate kinase, what may have contributed to the enhancements in the maximum rates of electron transport, carboxylation and photosynthetic capacity under elevated [CO2], although these responses were genotype dependent. The photosystem II efficiency, energy driven to photochemical events, non-structural carbohydrates, photosynthetic pigment and membrane permeability did not respond to [CO2] supply. Some alterations in total fatty acid content and the unsaturation level of the chloroplast membranes were noted but, apparently, did not affect photosynthetic functioning. Despite some differences among the genotypes, no clear species-dependent responses to elevated [CO2] were observed. Overall, as no apparent sign of photosynthetic down-regulation was found, our

  1. Impact of increasing Ultraviolet-B (UV-B) radiation on photosynthetic processes.

    Science.gov (United States)

    Kataria, Sunita; Jajoo, Anjana; Guruprasad, Kadur N

    2014-08-01

    Increased UV-B radiation on the earth's surface due to depletion of stratospheric ozone layer is one of the changes of current climate-change pattern. The deleterious effects of UV-B radiation on photosynthesis and photosynthetic productivity of plants are reviewed. Perusal of relevant literature reveals that UV-B radiation inflicts damage to the photosynthetic apparatus of green plants at multiple sites. The sites of damage include oxygen evolving complex, D1/D2 reaction center proteins and other components on the donor and acceptor sides of PS II. The radiation inactivates light harvesting complex II and alters gene expression for synthesis of PS II reaction center proteins. Mn cluster of water oxidation complex is the most important primary target of UV-B stress whereas D1 and D2 proteins, quinone molecules and cytochrome b are the subsequent targets of UV-B. In addition, photosynthetic carbon reduction is also sensitive to UV-B radiation which has a direct effect on the activity and content of Rubisco. Some indirect effects of UV-B radiation include changes in photosynthetic pigments, stomatal conductance and leaf and canopy morphology. The failure of protective mechanisms makes PS II further vulnerable to the UV-B radiation. Reactive oxygen species are involved in UV-B induced responses in plants, both as signaling and damaging agents. Exclusion of ambient UV components under field conditions results in the enhancement of the rate of photosynthesis, PS II efficiency and subsequently increases the biomass accumulation and crop yield. It is concluded that predicted future increase in UV-B irradiation will have significant impact on the photosynthetic efficiency and the productivity of higher plants. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Redox-State Dynamics of Ubiquinone-10 Imply Cooperative Regulation of Photosynthetic Membrane Expression in Rhodospirillum rubrum▿

    Science.gov (United States)

    Grammel, Hartmut; Ghosh, Robin

    2008-01-01

    It is now well established that, for photosynthetic bacteria, the aerobic-to-microaerophilic transition activates the membrane-bound sensor kinase RegB, which subsequently phosphorylates the transcriptional activator RegA, thereby inducing elevated levels of intracellular photosynthetic membranes. The mechanism of RegB activation—in particular, the role of ubiquinone-10—is controversial at present. One problem here is that very limited quantitative in vivo data for the response of the ubiquinone redox state to different cultivation conditions exist. Here, we utilize Rhodospirillum rubrum to study the correlation of the quinone redox state to the expression level of photosynthetic membranes and determine an effective response function directly. Our results show that changes in the photosynthetic membrane levels between 50 and 95% of that maximally attainable are associated with only a twofold change in the ubiquinol/ubiquinone ratio and are not necessarily proportional to the total levels of either quinone or [NAD+ + NADH]. There is no correlation between the redox potentials of the quinone and pyridine nucleotide pools. Hill function analysis of the photosynthetic membrane induction in response to the quinone redox state suggests that the induction process is highly cooperative. Our results are probably generally applicable to quinone redox regulation in bacteria. PMID:18487324

  3. Incidence of high blood pressure in children - effects of physical activity and sedentary behaviors: the IDEFICS study: High blood pressure, lifestyle and children.

    Science.gov (United States)

    de Moraes, Augusto César Ferreira; Carvalho, Heráclito Barbosa; Siani, Alfonso; Barba, Gianvincenzo; Veidebaum, Toomas; Tornaritis, Michael; Molnar, Denes; Ahrens, Wolfgang; Wirsik, Norman; De Henauw, Stefaan; Mårild, Staffan; Lissner, Lauren; Konstabel, Kenn; Pitsiladis, Yannis; Moreno, Luis A

    2015-02-01

    High blood pressure (HBP) is one of the most important risk factors for cardiovascular diseases and it has a high prevalence in pediatric populations. However, the determinants of the incidence of Pre-HBP and HBP in children are not well known. i) To describe the incidence of HBP in European children; and ii) to evaluate the effect of physical activity (PA) and sedentary behavior (SB) on the Pre-HBP and HBP. The IDEFICS cohort study. A total of 16,228 children 2-9years at baseline were recruited by complex sampling population-based survey in eight European countries. At baseline (T0), 5221 children were selected for accelerometer measurements; 5061 children were re-examined 2years later (T1). We estimated the incidence of Pre-HBP and HBP and evaluate the effect of PA and SB on the Pre-HBP and HBP, by computing relative risks and the corresponding 95% confidence intervals (RR, 95% CI). Incidences of Pre-HBP and HBP per year were: 121/1000 children and 110/1000 children, respectively. We found that children maintaining SB>2h/d during the two year follow-up showed a RR of having HBP of 1.28 (1.03-1.60). Children in T1 not performing the recommended amount of PA (<60min/d) have a RR of HBP of 1.53 (1.12 to 2.09). We found no association between pre-HBP and the behaviors. The incidence of pre-HBP and HBP is high in European children. Maintaining sedentary behaviors during childhood increases the risk of developing HBP after two years of follow-up. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  4. Human risk contributions in process industry: Guides for their pre-identification in well-structured activities and for post-incident analysis

    International Nuclear Information System (INIS)

    Pedersen, O.M.

    1985-05-01

    The report should be considered a guide for the treating of human errors: for identifying their possibilities of occurrence when designing well-structured human tasks and for their improvement when they occur in reality. For these purposes a strong coupling between predictive and retrospective analysis is emphasized: In order to control human errors, post-incident analysis of cases with human errors in a given industrial plant should be performed as means of feedback from reality for the verification of results of predictive analysis and also as general means of identifying and improving such human errors which cannot be expected covered by predictive analysis. Primarily, the guide addresses people with a knowledge of the technical plant in question and involved in the safety-oriented design and improvement of human activities and without a particular human factors background. The main report describes the procedures for post-incident analysis and for Work Analysis, which is a search strategy developed for well-defined activities, e.g. test and calibration, and constitutes a formalized procedure for the pre-identification of relevant human errors leading to a lack of task result and/or to immediate effects not covered by the lack of task result itself. Work Analysis and the post-incident analysis procedure are based on a common description system for human malfunctions. This system is explained in appendix and so are its underlying models and way of reasoning. Finally, a word index is provided for supporting the reader. (author)

  5. Identification of large variation in the photosynthetic induction response among 37 soybean [Glycine max (L.) Merr.] genotypes that is not correlated with steady-state photosynthetic capacity.

    Science.gov (United States)

    Soleh, M A; Tanaka, Y; Kim, S Y; Huber, S C; Sakoda, K; Shiraiwa, T

    2017-03-01

    Irradiance continuously fluctuates during the day in the field. The speed of the induction response of photosynthesis in high light affects the cumulative carbon gain of the plant and could impact growth and yield. The photosynthetic induction response and its relationship with the photosynthetic capacity under steady-state conditions (P max ) were evaluated in 37 diverse soybean [Glycine max (L.) Merr.] genotypes. The induction response of leaf photosynthesis showed large variation among the soybean genotypes. After 5 min illumination with strong light, genotype NAM23 had the highest leaf photosynthetic rate of 33.8 µmol CO 2 m -2  s -1 , while genotype NAM12 showed the lowest rate at 4.7 µmol CO 2 m -2  s -1 . Cumulative CO 2 fixation (CCF) during the first 5 min of high light exposure ranged from 5.5 mmol CO 2 m -2 for NAM23 to 0.81 mmol CO 2 m -2 for NAM12. The difference in the induction response among genotypes was consistent throughout the growth season. However, there was no significant correlation between CCF and P max among genotypes suggesting that different mechanisms regulate P max and the induction response. The observed variation in the induction response was mainly attributed to ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activation, but soybean lines differing in the induction response did not differ in the leaf content of Rubisco activase α- and β-proteins. Future studies will be focused on identifying molecular determinants of the photosynthetic induction response and determining whether this trait could be an important breeding target to achieve improved growth of soybeans in the field.

  6. Quantifying the effects of light intensity on bioproduction and maintenance energy during photosynthetic growth of Rhodobacter sphaeroides.

    Science.gov (United States)

    Imam, Saheed; Fitzgerald, Colin M; Cook, Emily M; Donohue, Timothy J; Noguera, Daniel R

    2015-02-01

    Obtaining a better understanding of the physiology and bioenergetics of photosynthetic microbes is an important step toward optimizing these systems for light energy capture or production of valuable commodities. In this work, we analyzed the effect of light intensity on bioproduction, biomass formation, and maintenance energy during photoheterotrophic growth of Rhodobacter sphaeroides. Using data obtained from steady-state bioreactors operated at varying dilution rates and light intensities, we found that irradiance had a significant impact on biomass yield and composition, with significant changes in photopigment, phospholipid, and biopolymer storage contents. We also observed a linear relationship between incident light intensity and H2 production rate between 3 and 10 W m(-2), with saturation observed at 100 W m(-2). The light conversion efficiency to H2 was also higher at lower light intensities. Photosynthetic maintenance energy requirements were also significantly affected by light intensity, with links to differences in biomass composition and the need to maintain redox homeostasis. Inclusion of the measured condition-dependent biomass and maintenance energy parameters and the measured photon uptake rate into a genome-scale metabolic model for R. sphaeroides (iRsp1140) significantly improved its predictive performance. We discuss how our analyses provide new insights into the light-dependent changes in bioenergetic requirements and physiology during photosynthetic growth of R. sphaeroides and potentially other photosynthetic organisms.

  7. Preillumination of lettuce seedlings with red light enhances the resistance of photosynthetic apparatus to UV-A.

    Science.gov (United States)

    Kreslavski, Vladimir D; Lyubimov, Valery Yu; Shirshikova, Galina N; Shmarev, Alexander N; Kosobryukhov, Anatoly A; Schmitt, Franz-Josef; Friedrich, Thomas; Allakhverdiev, Suleyman I

    2013-05-05

    Seedlings of 10-day-old lettuce (Lactuca sativa L., cultivar Berlin) were preilluminated by low intensity red light (λmax=660 nm, 10 min, 5 μmol quanta m(-2) s(-1)) and far-red light (λmax=730 nm, 10 min, 5 μmol quanta m(-2) s(-1)) to study the effect of pre-treatment on photosynthesis, photochemical activity of photosystem II (PSII), the contents of photosynthetic and UV-A-absorbing pigments (UAPs) and H2O2, as well as total and ascorbate peroxidase activities in cotyledonary leaves of seedlings exposed to UV-A. UV radiation reduced the photosynthetic rate (Pn), the activity of PSII, and the contents of Chl a and b, carotenoids and UAPs in the leaves, but increased the content of H2O2 and the total peroxidase activity. Preillumination with red light removed these effects of UV. In turn, the illumination with red light, then far-red light removed the effect of the red light. Illumination with red light alone increased the content of UAPs, as well as peroxidase activity. It is suggested that higher resistance of the lettuce photosynthetic apparatus to UV-A radiation is associated with involvement of the active form of phytochrome B, thereby increasing peroxidase activities as well as UAPs and saving preservation of photosynthetic pigment contents due to pre-illumination with red light. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Incidence, Clinical Presentation, and Outcome of Progressive Multifocal Leukoencephalopathy in HIV-Infected Patients during the Highly Active Antiretroviral Therapy Era: A Nationwide Cohort Study

    DEFF Research Database (Denmark)

    Engsig, Frederik Neess; Hansen, Ann-Brit Eg; Omland, Lars Haukali

    2008-01-01

    Background. @nbsp; Human immunodeficiency virus (HIV) infection predisposes to progressive multifocal leukoencephalopathy (PML). Here, we describe the incidence, presentation, and prognosis of PML in HIV-1-infected patients during the period before highly active antiretroviral therapy (HAART) (1995......(+) cell count, and 47% of cases were diagnosed by means of brain biopsy or polymerase chain reaction analysis for JC virus. The predominant neurological symptoms at presentation were coordination disturbance, cognitive defects, and limb paresis. Thirty-five patients died; the median survival time was 0.......4 years (95% confidence interval [CI], 0.0-0.7) in 1995-1996 and 1.8 years (95% CI, 0.6-3.0) in both 1997-1999 and 2000-2006. CD4(+) cell count >50 cells/muL at diagnosis of PML was significantly associated with reduced mortality. Conclusions. @nbsp; The incidence of PML in HIV-infected patients decreased...

  9. Alcohol facilitates CD1d loading, subsequent activation of NKT cells, and reduces the incidence of diabetes in NOD mice.

    Directory of Open Access Journals (Sweden)

    Karsten Buschard

    Full Text Available BACKGROUND: Ethanol ('alcohol' is a partly hydrophobic detergent that may affect the accessibility of glycolipids thereby influencing immunological effects of these molecules. METHODS: The study included cellular in vitro tests using α-galactosylceramide (αGalCer, and in vivo NOD mice experiments detecting diabetes incidence and performing behavioural and bacterial analyses. RESULTS: Alcohol in concentrations from 0.6% to 2.5% increased IL-2 production from NKT cells stimulated with αGalCer by 60% (p<0.05. CD1d expressed on HeLa cells contained significantly increasing amounts of αGalCer with increasing concentrations of alcohol, suggesting that alcohol facilitated the passive loading of αGalCer to CD1d. NOD mice were found to tolerate 5% ethanol in their drinking water without signs of impairment in liver function. Giving this treatment, the diabetes incidence declined significantly. Higher numbers of CD3+CD49b+ NKT cells were found in spleen and liver of the alcohol treated compared to the control mice (p<0.05, whereas the amount of CD4+Foxp3+ regulator T cells did not differ. Increased concentrations of IFN-γ were detected in 24-hour blood samples of alcohol treated mice. Behavioural studies showed no change in attitude of the ethanol-consuming mice, and bacterial composition of caecum samples was not affected by alcohol, disqualifying these as protective mechanisms. CONCLUSION: Alcohol facilitates the uptake of glycolipids and the stimulation of NKT cells, which are known to counteract Type 1 diabetes development. We propose that this is the acting mechanism by which treatment with alcohol reduces the incidence of diabetes in NOD mice. This is corroborated by epidemiology showing beneficial effect of alcohol to reduce the severity of atherosclerosis and related diseases.

  10. Photosynthetic energy conversion efficiency: setting a baseline for gauging future improvements in important food and biofuel crops.

    Science.gov (United States)

    Slattery, Rebecca A; Ort, Donald R

    2015-06-01

    The conversion efficiency (ε(c)) of absorbed radiation into biomass (MJ of dry matter per MJ of absorbed photosynthetically active radiation) is a component of yield potential that has been estimated at less than half the theoretical maximum. Various strategies have been proposed to improve ε(c), but a statistical analysis to establish baseline ε(c) levels across different crop functional types is lacking. Data from 164 published ε(c) studies conducted in relatively unstressed growth conditions were used to determine the means, greatest contributors to variation, and genetic trends in ε(c )across important food and biofuel crop species. ε(c) was greatest in biofuel crops (0.049-0.066), followed by C4 food crops (0.046-0.049), C3 nonlegumes (0.036-0.041), and finally C3 legumes (0.028-0.035). Despite confining our analysis to relatively unstressed growth conditions, total incident solar radiation and average growing season temperature most often accounted for the largest portion of ε(c) variability. Genetic improvements in ε(c), when present, were less than 0.7% per year, revealing the unrealized potential of improving ε(c) as a promising contributing strategy to meet projected future agricultural demand. © 2015 American Society of Plant Biologists. All Rights Reserved.

  11. Variability of photosynthetic parameters of Pinus sibirica Du Tour needles under changing climatic factors

    Directory of Open Access Journals (Sweden)

    A.P. Zotikova

    2013-12-01

    Full Text Available The air temperature and relative humidity and the intensity of photosynthetically active radiation are the basic ecological factors determining geographical distribution of a species. Wood plant adaptation depends on the intensity of physiological and biochemicalprocesses of plants as a response to changing environmental factors. Investigations to reveal (detect the variability of modification andgenetic components of the photosynthetic parameters in needles of the Siberian cedar (Pinus sibirica Du Tour mountain ecotypes, distributed in central part of the Altai Mountains, were carried out. Also, the survey was extended to some experiments with these ecotypes introduced to mild climate and flat regions from south-western of Siberia. The length and thickness of needles, the size of chloroplasts, content of the photosynthetic pigments, and the functional activity of chloroplastsat the level of photo system II were the evaluated traits. Growing under mountainous conditions (at about 2000m elevation, the two-year-old needles were shorter and thicker and contained very large in size chloroplasts while the content of chlorophylls and carotinoids was twice lower than that in the local ecotype growing in the lowlands. On the other hand, more green and yellow pigments were found in needles of mountain ecotypes planted in the lowlands compared to the local lowland ectype trees. A decrease in pool of the photosynthetic pigments in the highlands ecotypes is probably due to decreased biosynthesis andincreased photo-destruction caused by severe light and temperature conditions. These parameters are likely to be associated withmodifications due to intense insolation, low temperature, ozone concentration, UV radiation, and other negative factors that are morepronounced at high elevation. Despite the large pool of accumulated photosynthetic pigments, the functional activity of chloroplasts in themountain ecotype at the level

  12. Chromium removal from solution by five photosynthetic bacteria isolates.

    Science.gov (United States)

    Su, Yan-Qiu; Zhao, Yang-Juan; Wu, Nan; Chen, Yang-Er; Zhang, Wei-Jia; Qiao, Dai-Rong; Cao, Yi

    2018-02-01

    Biological method has been recognized as a low-cost and ecofriendly approach for removing heavy metals from aqueous wastes. In this study, the ability of five photosynthetic bacteria isolates (strains labeled SC01, HN02, SC05, JS01, and YN01) was examined for their ability to remove Cr from Cr-containing solutions. Furthermore, the possible removal mechanisms were elucidated by comparing chromium removal rates, antioxidant reaction, and accumulation of reactive oxygen species (ROS). Among the five bacteria, strains SC01 and SC05 presented the highest removal rates of chromium ions and the activity of cysteine desulfhydrase under Cr stress. They also showed lower levels of ROS and cell death than the other three bacteria strains under Cr stress. In addition, total bacteriochlorophyll content and activities of six antioxidant enzymes in SC01 were highest among these selected strains. On the contrary, strain HN02 presented the lowest level of Cr removal and the lowest activities of antioxidant enzymes. It also exhibited the highest level of ROS under Cr(VI) stress. Overall, these results show that the strains SC01 and SC05 have good Cr removal ability and could be used for removal of Cr in industrial effluents.

  13. Physiological and photosynthetic response of quinoa to drought stress

    Directory of Open Access Journals (Sweden)

    Rachid Fghire

    2015-06-01

    Full Text Available Water shortage is a critical problem touching plant growth and yield in semi-arid areas, for instance the Mediterranean región. For this reason was studied the physiological basis of drought tolerance of a new, drought tolerant crop quinoa (Chenopodium quinoa Willd. tested in Morocco in two successive seasons, subject to four irrigation treatments (100, 50, and 33%ETc, and rainfed. The chlorophyll a fluorescence transients were analyzed by the JIP-test to transíate stress-induced damage in these transients to changes in biophysical parameter's allowing quantification of the energy flow through the photosynthetic apparatus. Drought stress induced a significant decrease in the maximum quantum yield of primary photochemistry (Φpo = Fv/Fm, and the quantum yield of electron transport (Φeo. The amount of active Photosystem II (PSII reaction centers (RC per excited cross section (RC/CS also decreased when exposed to the highest drought stress. The effective antenna size of active RCs (ABS/RC increased and the effective dissipation per active reaction centers (DIo/RC increased by increasing drought stress during the growth season in comparison to the control. However the performance index (PI, was a very sensitive indicator of the physiological status of plants. Leaf area index, leaf water potential and stomatal conductance decreased as the drought increased. These results indicate that, in quinoa leaf, JIP-test can be used as a sensitive method for measuring drought stress effects.

  14. Halogenated 1-Hydroxynaphthalene-2-Carboxanilides Affecting Photosynthetic Electron Transport in Photosystem II

    Czech Academy of Sciences Publication Activity Database

    Goněc, T.; Kos, J.; Pesko, M.; Dohanosová, J.; Oravec, Michal; Liptaj, T.; Králová, K.; Jampílek, J.

    2017-01-01

    Roč. 22, č. 10 (2017), č. článku 1709. ISSN 1420-3049 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : hydroxynaphthalene-carboxamides * photosynthetic electron transport (PET) inhibition * spinach chloroplasts * structure-activity relationships Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 2.861, year: 2016

  15. Photosynthetic behavior, growth and essential oil production of Melissa officinalis L. cultivated under colored shade nets

    OpenAIRE

    Graziele C Oliveira; Willyam L Vieira; Suzana C Bertolli; Ana Claudia Pacheco

    2016-01-01

    The modulation of light is of importance during cultivation of medicinal plants to obtain desirable morphological and physiological changes associated with the maximum production of active principles. This study aimed to evaluate the effect of the light spectrum transmitted by colored shade nets on growth, essential oil production and photosynthetic behavior in plants of lemon balm (Melissa officinalis L.) Plants were cultivated in pots for 4-mo under black, red, and blue nets with 50% shadin...

  16. Resistance of Arabidopsis thaliana L. photosynthetic apparatus to UV-B is reduced by deficit of phytochromes B and A.

    Science.gov (United States)

    Khudyakova, Aleksandra Yu; Kreslavski, Vladimir D; Shirshikova, Galina N; Zharmukhamedov, Sergey K; Kosobryukhov, Anatoly A; Allakhverdiev, Suleyman I

    2017-04-01

    The photosynthetic responses of 25-day-old Arabidopsis phyA phyB double mutant (DM) compared with the wild type (WT) to UV-B radiation (1Wm -2 , 30min) were investigated. UV-B irradiation led to reduction of photosystem 2 (PS-2) activity and the photosynthetic rate. In plants grown under both white and red light (λ m - 660nm) the reduction was greater in DM plants compared to the WT. Without UV-B irradiation a decrease in PS-2 activity was observed in DM grown under RL only. It is assumed that the lower content of UV-absorbing pigments and carotenoids observed in DM may be one of the reasons of reduced PS-2 resistance to UV-B. Higher decrease in activities under UV in DM plants grown under RL compared to DM plants grown under white light is likely due to the lack of activity of cryptochromes in plants grown under red light. Rates of post-stress recovery of photosynthetic activity of DM compared with WT plants under white and red light of low intensity were studied. Almost complete recovery of the activity was found which was not observed under dark conditions and in the presence of a protein synthesis inhibitor, chloramphenicol. It is assumed that phytochrome system participates in stress-protective mechanisms of the photosynthetic apparatus to UV-radiation. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Leisure-time physical activity and risk of disability incidence: A 12-year prospective cohort study among young elderly of the same age at baseline.

    Science.gov (United States)

    Matsunaga, Takashi; Naito, Mariko; Wakai, Kenji; Ukawa, Shigekazu; Zhao, Wenjing; Okabayashi, Satoe; Ando, Masahiko; Kawamura, Takashi; Tamakoshi, Akiko

    2017-11-01

    To clarify the role of physical activity in preventing disability in Japan, we investigated the association between amount of leisure-time physical activity and incidence of disability among the young elderly. In the New Integrated Suburban Seniority Investigation (NISSIN) project conducted from 1996 to 2013, we followed 2888 community-dwelling adults aged 64-65 years with no history of cerebrovascular disease for a median follow-up of 11.6 years. Disabilities were defined as follows based on the classifications of the Japanese long-term care insurance system: 1) support or care levels (support levels 1-2 or care levels 1-5); 2) care levels 2-5; 3) support or care levels with dementia; and 4) care levels 2-5 or death. In addition, we also assessed 5) all-cause mortality. After controlling for sociodemographic, lifestyle, and medical factors, male participants reporting an activity level of 18.1 metabolic equivalent (MET)-hours/week (the median among those with activities) or more had 52% less risk of being classified as support or care levels with dementia compared with the no activity group (hazard ratio 0.48; 95% confidence interval, 0.25-0.94). No significant association was found among women between amount of leisure-time physical activity and incidence of disability. We identified an inverse dose-response relationship between the amount of leisure-time physical activity and the risk of disability with dementia in men. Therefore, a higher level of physical activity should be recommended to young elderly men to prevent disability with dementia. Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  18. Leisure-time physical activity and risk of disability incidence: A 12-year prospective cohort study among young elderly of the same age at baseline

    Directory of Open Access Journals (Sweden)

    Takashi Matsunaga

    2017-11-01

    Full Text Available Background: To clarify the role of physical activity in preventing disability in Japan, we investigated the association between amount of leisure-time physical activity and incidence of disability among the young elderly. Methods: In the New Integrated Suburban Seniority Investigation (NISSIN project conducted from 1996 to 2013, we followed 2888 community-dwelling adults aged 64–65 years with no history of cerebrovascular disease for a median follow-up of 11.6 years. Disabilities were defined as follows based on the classifications of the Japanese long-term care insurance system: 1 support or care levels (support levels 1–2 or care levels 1–5; 2 care levels 2–5; 3 support or care levels with dementia; and 4 care levels 2–5 or death. In addition, we also assessed 5 all-cause mortality. Results: After controlling for sociodemographic, lifestyle, and medical factors, male participants reporting an activity level of 18.1 metabolic equivalent (MET-hours/week (the median among those with activities or more had 52% less risk of being classified as support or care levels with dementia compared with the no activity group (hazard ratio 0.48; 95% confidence interval, 0.25–0.94. No significant association was found among women between amount of leisure-time physical activity and incidence of disability. Conclusion: We identified an inverse dose–response relationship between the amount of leisure-time physical activity and the risk of disability with dementia in men. Therefore, a higher level of physical activity should be recommended to young elderly men to prevent disability with dementia.

  19. Tea Drinking and Its Association with Active Tuberculosis Incidence among Middle-Aged and Elderly Adults: The Singapore Chinese Health Study.

    Science.gov (United States)

    Soh, Avril Zixin; Pan, An; Chee, Cynthia Bin Eng; Wang, Yee-Tang; Yuan, Jian-Min; Koh, Woon-Puay

    2017-05-25

    Experimental studies showed that tea polyphenols may inhibit growth of Mycobacterium tuberculosis . However, no prospective epidemiologic study has investigated tea drinking and the risk of active tuberculosis. We investigated this association in the Singapore Chinese Health Study, a prospective population-based cohort of 63,257 Chinese aged 45-74 years recruited between 1993 and 1998 in Singapore. Information on habitual drinking of tea (including black and green tea) and coffee was collected via structured questionnaires. Incident cases of active tuberculosis were identified via linkage with the nationwide tuberculosis registry up to 31 December 2014. Cox proportional hazard models were used to estimate the relation of tea and coffee consumption with tuberculosis risk. Over a mean 16.8 years of follow-up, we identified 1249 incident cases of active tuberculosis. Drinking either black or green tea was associated with a dose-dependent reduction in tuberculosis risk. Compared to non-drinkers, the hazard ratio (HR) (95% confidence interval (CI)) was 1.01 (0.85-1.21) in monthly tea drinkers, 0.84 (0.73-0.98) in weekly drinkers, and 0.82 (0.71-0.96) in daily drinkers ( p for trend = 0.003). Coffee or caffeine intake was not significantly associated with tuberculosis risk. In conclusion, regular tea drinking was associated with a reduced risk of active tuberculosis.

  20. Tea Drinking and Its Association with Active Tuberculosis Incidence among Middle-Aged and Elderly Adults: The Singapore Chinese Health Study

    Directory of Open Access Journals (Sweden)

    Avril Zixin Soh

    2017-05-01

    Full Text Available Experimental studies showed that tea polyphenols may inhibit growth of Mycobacterium tuberculosis. However, no prospective epidemiologic study has investigated tea drinking and the risk of active tuberculosis. We investigated this association in the Singapore Chinese Health Study, a prospective population-based cohort of 63,257 Chinese aged 45–74 years recruited between 1993 and 1998 in Singapore. Information on habitual drinking of tea (including black and green tea and coffee was collected via structured questionnaires. Incident cases of active tuberculosis were identified via linkage with the nationwide tuberculosis registry up to 31 December 2014. Cox proportional hazard models were used to estimate the relation of tea and coffee consumption with tuberculosis risk. Over a mean 16.8 years of follow-up, we identified 1249 incident cases of active tuberculosis. Drinking either black or green tea was associated with a dose-dependent reduction in tuberculosis risk. Compared to non-drinkers, the hazard ratio (HR (95% confidence interval (CI was 1.01 (0.85–1.21 in monthly tea drinkers, 0.84 (0.73–0.98 in weekly drinkers, and 0.82 (0.71–0.96 in daily drinkers (p for trend = 0.003. Coffee or caffeine intake was not significantly associated with tuberculosis risk. In conclusion, regular tea drinking was associated with a reduced risk of active tuberculosis.

  1. Photosynthetic performance in Antarctic lichens with different growth forms reflect the diversity of lichenized algal adaptation to microhabitats

    Directory of Open Access Journals (Sweden)

    Cao Shunan

    2015-06-01

    Full Text Available Lichens, as typical obligate associations between lichenized fungi and their photosynthetic partners, are dominant in Antarctica. Three Antarctic lichens, Ochrolechia frigida, Umbilicaria antarctica, and Usnea aurantiacoatra with different growth forms, were sampled nearby the Great Wall Station, King George Island. Molecular data revealed that the photosynthetic algae in these three lichens were Trebouxia jamesii. The net photo− synthesis (Pn of three individuals from these species, together with environmental factors such as light and temperature, were recorded by CO2 gas exchange measurements using a CI−340 portable photosynthetic system in situ. Differences between T(leaf (the temperature of the thalli and T(air (the air temperature for these lichens were not consistent, which reflected that environment and the growth form of thalli could affect T(leaf significantly. Strong irradiation was expected to have adverse effects on Pn of Ochrolechia frigida and Umbilicaria antarctica whose thalli spread flat; but this photoinhibition had little effect on Usnea aurantiacoatra with exuberant tufted thallus. These results indicated that photosynthetic activity in lichens was affected by the growth forms of thalli besides microhabitat factors. One species of lichenized alga could exhibit diversified types of photosynthetic behavior when it was associated with various lichenized fungi in different microhabitats. It will be helpful for understanding how lichens are able to adapt to and colonize in extreme environments.

  2. A novel potassium channel in photosynthetic cyanobacteria.

    Directory of Open Access Journals (Sweden)

    Manuela Zanetti

    Full Text Available Elucidation of the structure-function relationship of a small number of prokaryotic ion channels characterized so far greatly contributed to our knowledge on basic mechanisms of ion conduction. We identified a new potassium channel (SynK in the genome of the cyanobacterium Synechocystis sp. PCC6803, a photosynthetic model organism. SynK, when expressed in a K(+-uptake-system deficient E. coli strain, was able to recover growth of these organisms. The protein functions as a potassium selective ion channel when expressed in Chinese hamster ovary cells. The location of SynK in cyanobacteria in both thylakoid and plasmamembranes was revealed by immunogold electron microscopy and Western blotting of isolated membrane fractions. SynK seems to be conserved during evolution, giving rise to a TPK (two-pore K(+ channel family member which is shown here to be located in the thylakoid membrane of Arabidopsis. Our work characterizes a novel cyanobacterial potassium channel and indicates the molecular nature of the first higher plant thylakoid cation channel, opening the way to functional studies.

  3. Photosynthetic efficiency of Chlamydomonas reinhardtii in flashing light

    NARCIS (Netherlands)

    Vejrazka, C.; Janssen, M.G.J.; Streefland, M.; Wijffels, R.H.

    2011-01-01

    Efficient light to biomass conversion in photobioreactors is crucial for economically feasible microalgae production processes. It has been suggested that photosynthesis is enhanced in short light path photobioreactors by mixing-induced flashing light regimes. In this study, photosynthetic

  4. Photosynthetic and nitrogen fixation capability in several soybean mutant lines

    International Nuclear Information System (INIS)

    Gandanegara, S.; Hendratno, K.

    1987-01-01

    Photosynthetic and nitrogen fixation capability in several soybean mutant lines. A greenhouse experiment has been carried out to study photosynthetic and nitrogen fixation capability of five mutant lines and two soybean varieties. An amount of 330 uCi of 14 CO 2 was fed to the plants including of the non-fixing reference crop (Chippewa non-nodulating isoline). Nitrogen fixation measurements was carried out using 15 N isotope dilution technique according to A-value concept. Results showed that beside variety/mutant lines, plant growth also has important role in photosynthetic and N fixing capability. Better growth and a higher photosynthetic capability in Orba, mutant lines nos. 63 and 65 resulted in a greater amount of N 2 fixed (mg N/plant) than other mutant lines. (author). 12 refs.; 5 figs

  5. Quantifying Reversible Oxidation of Protein Thiols in Photosynthetic Organisms

    Science.gov (United States)

    Slade, William O.; Werth, Emily G.; McConnell, Evan W.; Alvarez, Sophie; Hicks, Leslie M.

    2015-04-01

    Photosynthetic organisms use dynamic post-translational modifications to survive and adapt, which include reversible oxidative modifications of protein thiols that regulate protein structure, function, and activity. Efforts to quantify thiol modifications on a global scale have relied upon peptide derivatization, typically using isobaric tags such as TMT, ICAT, or iTRAQ that are more expensive, less accurate, and provide less proteome coverage than label-free approaches—suggesting the need for improved experimental designs for studies requiring maximal coverage and precision. Herein, we present the coverage and precision of resin-assisted thiol enrichment coupled to label-free quantitation for the characterization of reversible oxidative modifications on protein thiols. Using C. reinhardtii and Arabidopsis as model systems for algae and plants, we quantified 3662 and 1641 unique cysteinyl peptides, respectively, with median coefficient of variation (CV) of 13% and 16%. Further, our method is extendable for the detection of protein abundance changes and stoichiometries of cysteine oxidation. Finally, we demonstrate proof-of-principle for our method, and reveal that exogenous hydrogen peroxide treatment regulates the C. reinhardtii redox proteome by increasing or decreasing the level of oxidation of 501 or 67 peptides, respectively. As protein activity and function is controlled by oxidative modifications on protein thiols, resin-assisted thiol enrichment coupled to label-free quantitation can reveal how intracellular and environmental stimuli affect plant survival and fitness through oxidative stress.

  6. Tree Species with Photosynthetic Stems Have Greater Nighttime Sap Flux.

    Science.gov (United States)

    Chen, Xia; Gao, Jianguo; Zhao, Ping; McCarthy, Heather R; Zhu, Liwei; Ni, Guangyan; Ouyang, Lei

    2018-01-01

    An increasing body of evidence has shown that nighttime sap flux occurs in most plants, but the physiological implications and regulatory mechanism are poorly known. The significance of corticular photosynthesis has received much attention during the last decade, however, the knowledge of the relationship between corticular photosynthesis and nocturnal stem sap flow is limited at present. In this study, we divided seven tree species into two groups according to different photosynthetic capabilities: trees of species with ( Castanopsis hystrix, Michelia macclurei, Eucalyptus citriodora , and Eucalyptus grandis × urophylla ) and without ( Castanopsis fissa, Schima superba , and Acacia auriculiformis ) photosynthetic stems, and the sap flux ( J s ) and chlorophyll fluorescence parameters for these species were measured. One-way ANOVA analysis showed that the F v / F m (Maximum photochemical quantum yield of PSII) and Φ PSII (effective photochemical quantum yield of PSII) values were lower in non-photosynthetic stem species compared to photosynthetic stem species. The linear regression analysis showed that J s,d (daytime sap flux) and J s,n (nighttime sap flux) of non-photosynthetic stem species was 87.7 and 60.9% of the stem photosynthetic species. Furthermore, for a given daytime transpiration water loss, total nighttime sap flux was higher in species with photosynthetic stems (Slope SMA = 2.680) than in non-photosynthetic stems species (Slope SMA = 1.943). These results mean that stem corticular photosynthesis has a possible effect on the nighttime water flow, highlighting the important eco-physiological relationship between nighttime sap flux and corticular photosynthesis.

  7. Tree Species with Photosynthetic Stems Have Greater Nighttime Sap Flux

    Science.gov (United States)

    Chen, Xia; Gao, Jianguo; Zhao, Ping; McCarthy, Heather R.; Zhu, Liwei; Ni, Guangyan; Ouyang, Lei

    2018-01-01

    An increasing body of evidence has shown that nighttime sap flux occurs in most plants, but the physiological implications and regulatory mechanism are poorly known. The significance of corticular photosynthesis has received much attention during the last decade, however, the knowledge of the relationship between corticular photosynthesis and nocturnal stem sap flow is limited at present. In this study, we divided seven tree species into two groups according to different photosynthetic capabilities: trees of species with (Castanopsis hystrix, Michelia macclurei, Eucalyptus citriodora, and Eucalyptus grandis × urophylla) and without (Castanopsis fissa, Schima superba, and Acacia auriculiformis) photosynthetic stems, and the sap flux (Js) and chlorophyll fluorescence parameters for these species were measured. One-way ANOVA analysis showed that the Fv/Fm (Maximum photochemical quantum yield of PSII) and ΦPSII (effective photochemical quantum yield of PSII) values were lower in non-photosynthetic stem species compared to photosynthetic stem species. The linear regression analysis showed that Js,d (daytime sap flux) and Js,n (nighttime sap flux) of non-photosynthetic stem species was 87.7 and 60.9% of the stem photosynthetic species. Furthermore, for a given daytime transpiration water loss, total nighttime sap flux was higher in species with photosynthetic stems (SlopeSMA = 2.680) than in non-photosynthetic stems species (SlopeSMA = 1.943). These results mean that stem corticular photosynthesis has a possible effect on the nighttime water flow, highlighting the important eco-physiological relationship between nighttime sap flux and corticular photosynthesis. PMID:29416547

  8. Production of bioplastics and hydrogen gas by photosynthetic microorganisms

    Science.gov (United States)

    Yasuo, Asada; Masato, Miyake; Jun, Miyake

    1998-03-01

    Our efforts have been aimed at the technological basis of photosynthetic-microbial production of materials and an energy carrier. We report here accumulation of poly-(3-hydroxybutyrate) (PHB), a raw material of biodegradable plastics and for production of hydrogen gas, and a renewable energy carrier by photosynthetic microorganisms (tentatively defined as cyanobacteria plus photosynthetic bateria, in this report). A thermophilic cyanobacterium, Synechococcus sp. MA19 that accumulates PHB at more than 20% of cell dry wt under nitrogen-starved conditions was isolated and microbiologically identified. The mechanism of PHB accumulation was studied. A mesophilic Synechococcus PCC7942 was transformed with the genes encoding PHB-synthesizing enzymes from Alcaligenes eutrophus. The transformant accumulated PHB under nitrogen-starved conditions. The optimal conditions for PHB accumulation by a photosynthetic bacterium grown on acetate were studied. Hydrogen production by photosynthetic microorganisms was studied. Cyanobacteria can produce hydrogen gas by nitrogenase or hydrogenase. Hydrogen production mediated by native hydrogenase in cyanobacteria was revealed to be in the dark anaerobic degradation of intracellular glycogen. A new system for light-dependent hydrogen production was targeted. In vitro and in vivo coupling of cyanobacterial ferredoxin with a heterologous hydrogenase was shown to produce hydrogen under light conditions. A trial for genetic trasformation of Synechococcus PCC7942 with the hydrogenase gene from Clostridium pasteurianum is going on. The strong hydrogen producers among photosynthetic bacteria were isolated and characterized. Co-culture of Rhodobacter and Clostriumdium was applied to produce hydrogen from glucose. Conversely in the case of cyanobacteria, genetic regulation of photosynthetic proteins was intended to improve conversion efficiency in hydrogen production by the photosynthetic bacterium, Rhodobacter sphaeroides RV. A mutant acquired by

  9. Tree Species with Photosynthetic Stems Have Greater Nighttime Sap Flux

    Directory of Open Access Journals (Sweden)

    Xia Chen

    2018-01-01

    Full Text Available An increasing body of evidence has shown that nighttime sap flux occurs in most plants, but the physiological implications and regulatory mechanism are poorly known. The significance of corticular photosynthesis has received much attention during the last decade, however, the knowledge of the relationship between corticular photosynthesis and nocturnal stem sap flow is limited at present. In this study, we divided seven tree species into two groups according to different photosynthetic capabilities: trees of species with (Castanopsis hystrix, Michelia macclurei, Eucalyptus citriodora, and Eucalyptus grandis × urophylla and without (Castanopsis fissa, Schima superba, and Acacia auriculiformis photosynthetic stems, and the sap flux (Js and chlorophyll fluorescence parameters for these species were measured. One-way ANOVA analysis showed that the Fv/Fm (Maximum photochemical quantum yield of PSII and ΦPSII (effective photochemical quantum yield of PSII values were lower in non-photosynthetic stem species compared to photosynthetic stem species. The linear regression analysis showed that Js,d (daytime sap flux and Js,n (nighttime sap flux of non-photosynthetic stem species was 87.7 and 60.9% of the stem photosynthetic species. Furthermore, for a given daytime transpiration water loss, total nighttime sap flux was higher in species with photosynthetic stems (SlopeSMA = 2.680 than in non-photosynthetic stems species (SlopeSMA = 1.943. These results mean that stem corticular photosynthesis has a possible effect on the nighttime water flow, highlighting the important eco-physiological relationship between nighttime sap flux and corticular photosynthesis.

  10. Normal incidence X-ray telescope power spectra of X-ray emission from solar active regions. I - Observations. II - Theory

    Science.gov (United States)

    Gomez, Daniel O.; Martens, Petrus C. H.; Golub, Leon

    1993-01-01

    Fourier analysis is applied to very high resolution image of coronal active regions obtained by the Normal Incidence X-Ray Telescope is used to find a broad isotropic power-law spectrum of the spatial distribution of soft X-ray intensities. Magnetic structures of all sizes are present down to the resolution limit of the instrument. Power spectra for the X-ray intensities of a sample of topologically different active regions are found which fall off with increasing wavenumber as 1/k-cubed. A model is presented that relates the basic features of coronal magnetic fluctuations to the subphotospheric hydrodynamic turbulence that generates them. The model is used to find a theoretical power spectrum for the X-ray intensity which falls off with increasing wavenumber as 1/k-cubed. The implications of a turbulent regime in active regions are discussed.

  11. Fourier transform infrared difference spectroscopy for studying the molecular mechanism of photosynthetic water oxidation

    Directory of Open Access Journals (Sweden)

    Hsiu-An eChu

    2013-05-01

    Full Text Available The photosystem II reaction center mediates the light-induced transfer of electrons from water to plastoquinone, with concomitant production of O2. Water oxidation chemistry occurs in the oxygen-evolving complex (OEC, which consists of an inorganic Mn4CaO5 cluster and its surrounding protein matrix. Light-induced Fourier transform infrared (FTIR difference spectroscopy has been successfully used to study the molecular mechanism of photosynthetic water oxidation. This powerful technique has enabled the characterization of the dynamic structural changes in active water molecules, the Mn4CaO5 cluster, and its surrounding protein matrix during the catalytic cycle. This mini-review presents an overview of recent important progress in FTIR studies of the OEC and implications for revealing the molecular mechanism of photosynthetic water oxidation.

  12. Photosynthetic metabolism of malate and aspartate in Flaveria trinervia a C4 dicot

    International Nuclear Information System (INIS)

    Moore, B.A.

    1986-01-01

    C 4 species are known to vary in their apparent relative use of malate and aspartate to mediate carbon flux through the C 4 cycle. These studies investigate some of the adjustments in photosynthetic carbon metabolism that occur during a dark to light transition and during expansion of leaves of Flaveria trinervia, a C 4 dicot. Enzyme localization studies with isolated leaf mesophyll and bundle sheath protoplasts, indicated that both C 4 acids are formed in the mesophyll chloroplast, and that aspartate is metabolized to malate in the bundle sheath chloroplast prior to decaroxylation there. During photosynthetic induction, the partitioning of 14 CO 2 between malate and aspartate showed a single oscillation of increased aspartate labelling after 5 min of illumination. Turnover of [4-14C] (malate plus aspartate) was slow initially during illumination, prior to establishment of active pools of C 4 cycle metabolites

  13. Rice Photosynthetic Productivity and PSII Photochemistry under Nonflooded Irrigation

    Directory of Open Access Journals (Sweden)

    Haibing He

    2014-01-01

    Full Text Available Nonflooded irrigation is an important water-saving rice cultivation technology, but little is known on its photosynthetic mechanism. The aims of this work were to investigate photosynthetic characteristics of rice during grain filling stage under three nonflooded irrigation treatments: furrow irrigation with plastic mulching (FIM, furrow irrigation with nonmulching (FIN, and drip irrigation with plastic mulching (DI. Compared with the conventional flooding (CF treatment, those grown in the nonflooded irrigation treatments showed lower net photosynthetic rate (PN, lower maximum quantum yield (Fv/Fm, and lower effective quantum yield of PSII photochemistry (ΦPSII. And the poor photosynthetic characteristics in the nonflooded irrigation treatments were mainly attributed to the low total nitrogen content (TNC. Under non-flooded irrigation, the PN, Fv/Fm, and ΦPSII significantly decreased with a reduction in the soil water potential, but these parameters were rapidly recovered in the DI and FIM treatments when supplementary irrigation was applied. Moreover, The DI treatment always had higher photosynthetic productivity than the FIM and FIN treatments. Grain yield, matter translocation, and dry matter post-anthesis (DMPA were the highest in the CF treatment, followed by the DI, FIM, and FIN treatments in turn. In conclusion, increasing nitrogen content in leaf of rice plants could be a key factor to improve photosynthetic capacity in nonflooded irrigation.

  14. Drought-induced photosynthetic inhibition and autumn recovery in two Mediterranean oak species (Quercus ilex and Quercus suber).

    Science.gov (United States)

    Vaz, M; Pereira, J S; Gazarini, L C; David, T S; David, J S; Rodrigues, A; Maroco, J; Chaves, M M

    2010-08-01

    Responses of leaf water relations and photosynthesis to summer drought and autumn rewetting were studied in two evergreen Mediterranean oak species, Quercus ilex spp. rotundifolia and Quercus suber. The predawn leaf water potential (Ψ(lPD)), stomatal conductance (gs) and photosynthetic rate (A) at ambient conditions were measured seasonally over a 3-year period. We also measured the photosynthetic response to light and to intercellular CO₂ (A/PPFD and A/C(i) response curves) under water stress (summer) and after recovery due to autumn rainfall. Photosynthetic parameters, Vc(max), J(max) and triose phosphate utilization (TPU) rate, were estimated using the Farquhar model. RuBisCo activity, leaf chlorophyll, leaf nitrogen concentration and leaf carbohydrate concentration were also measured. All measurements were performed in the spring leaves of the current year. In both species, the predawn leaf water potential, stomatal conductance and photosynthetic rate peaked in spring, progressively declined throughout the summer and recovered upon autumn rainfall. During the drought period, Q. ilex maintained a higher predawn leaf water potential and stomatal conductance than Q. suber. During this period, we found that photosynthesis was not only limited by stomatal closure, but was also downregulated as a consequence of a decrease in the maximum carboxylation rate (Vc(max)) and the light-saturated rate of photosynthetic electron transport (J(max)) in both species. The Vc(max) and J(max) increased after the first autumnal rains and this increase was related to RuBisCo activity, leaf nitrogen concentration and chlorophyll concentration. In addition, an increase in the TPU rate and in soluble leaf sugar concentration was observed in this period. The results obtained indicate a high resilience of the photosynthetic apparatus to summer drought as well as good recovery in the following autumn rains of these evergreen oak species.

  15. Wintertime photosynthetic capacity of black spruce (Picea mariana) in boreal forests in interior Alaska

    Science.gov (United States)

    Fujino, T.; Koyama, L. A.; Kielland, K.

    2015-12-01

    In boreal forests, the growing season is short, and winter temperature is low and fluctuates from considerably below freezing point to intermittent warm spells. Under such conditions, it is important for plants to retain their photosynthetic capacity throughout the winter. To understand the importance of wintertime photosynthetic activity for evergreen boreal coniferous species, the light response curve of black spruce (Picea mariana) was monitored in Fairbanks, interior Alaska (64°86'N, 147°84'W) throughout the winter, and compared with those in the summer. Cuttings of black spruce were collected, and gas exchange of their needles was measured in the incubator set to 0 °C using a gas analyzer (LI-6400, Li-Cor Inc.). A non-rectangular hyperbolic model was fitted to these data, and physiological parameters such as the maximum photosynthesis rate, dark respiration rate and quantum yield of photosynthesis were extracted. The apparent quantum yield of photosynthesis remained low throughout the winter for black spruce. The maximum photosynthesis rate was downregulated as air temperature fell in early winter, but did not increase in March when air temperature rose. This suggests that photoinhibition may occur more strongly in March than in early winter. The average maximum rates of photosynthesis in winter were almost 10% of the value measured in summer. On the other hand, the dark respiration rate did not considerably differ between seasons. These results provide new insights into winter photosynthetic activity and its role in boreal forest ecosystems.

  16. Yields, photosynthetic efficiencies, and proximate chemical composition of dense cultures of marine microalgae. A subcontract report

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, W.H.; Seibert, D.L.R.; Alden, M.; Eldridge, P.; Neori, A.

    1983-07-01

    The yields, photosynthetic efficiencies, and proximate composition of several microalgae were compared in dense cultures grown at light intensities up to 70% sunlight. Yields ranged from 3.4 to 21.7 g dry weight/m/sup 2/ day. The highest yield was obtained with Phaeodactylum; the lowest in Botryococcus cultures. The same species had the highest and lowest efficiencies of utilization of photosynthetically active radiation. In nitrogen-sufficient cells of all but one species, most of the dry weight consisted of protein. Lipid content of all species was 20 to 29%, and carbohydrate content 11 to 23%. Lipid content increased somewhat in N-deficient Phaeodactylum and Isochrysis cells, but decreased in deficient Monallanthus cells. Because the overall dry weight yield was reduced by deficiency, lipid yields did not increase. However, since the carbohydrate content increased to about 65% in N-deficient Dunaliella and Tetraselmis cells, the carbohydrate yield increased. In Phaeodactylum the optimum light intensity was about 40% of full sunlight. Most experimets with this alga included a CUSO/sub 4/ filter to decrease infrared irradiance. When this filter was removed, the yield increased because more red light in the photosynthetically active spectral range was included. These results should prove useful to workers attempting to maximize yields and efficiencies, but additional studies are needed. 69 references, 27 figures, 18 tables.

  17. Does a Higher Incidence of Break Times in Primary Schools Result in Children Being More Physically Active?

    Science.gov (United States)

    Kobel, Susanne; Kettner, Sarah; Erkelenz, Nanette; Kesztyüs, Dorothea; Steinacker, Jürgen M.

    2015-01-01

    Background: Regular physical activity (PA) has multiple benefits to health; however, the majority of schoolchildren do not reach PA guidelines of 60 minutes of moderate to vigorous PA (MVPA) daily. During the school day, break times are often the only opportunity for children to be physically active. This study investigated PA levels during school…

  18. Impact of UV-radiation on viability, photosynthetic characteristics and DNA of brown algal zoospores : implications for depth zonation

    NARCIS (Netherlands)

    Wiencke, C; Gomez, [No Value; Pakker, H; Flores-Moya, A; Altamirano, M; Hanelt, D; Bischof, K; Figueroa, FL

    2000-01-01

    Measurements of photosynthesis, germination capacity and assessment of DNA damage were carried out in the laboratory to determine the effect of different conditions of ultraviolet (UV) and photosynthetically active radiation (PAR) on zoospores of various large brown algae collected on Spitsbergen

  19. Photosynthetic and Behavioral Versatility of the Cyanobacterium Oscillatoria-Boryana in a Sulfide-Rich Microbial Mat

    DEFF Research Database (Denmark)

    CASTENHOLZ, RW; JØRGENSEN, BB; DAMELIO, E.

    1991-01-01

    The diel pattern of vertical migratory movements and photosynthetic activity of Oscillatoria cf. boryana was monitored periodically in microbial mats of a shallow tepid pond fed by sulfide-rich, hot, geothermal spring water in Rotorua, New Zealand. Motile O. boryana formed a conspicuous...

  20. Differential Allocation to Photosynthetic and Non-Photosynthetic Nitrogen Fractions among Native and Invasive Species

    Science.gov (United States)

    Funk, Jennifer L.; Glenwinkel, Lori A.; Sack, Lawren

    2013-01-01

    Invasive species are expected to cluster on the “high-return” end of the leaf economic spectrum, displaying leaf traits consistent with higher carbon assimilation relative to native species. Intra-leaf nitrogen (N) allocation should support these physiological differences; however, N biochemistry has not been examined in more than a few invasive species. We measured 34 leaf traits including seven leaf N pools for five native and five invasive species from Hawaii under low irradiance to mimic the forest understory environment. We found several trait differences between native and invasive species. In particular, invasive species showed preferential N allocation to metabolism (amino acids) rather than photosynthetic light reactions (membrane-bound protein) by comparison with native species. The soluble protein concentration did not vary between groups. Under these low irradiance conditions, native species had higher light-saturated photosynthetic rates, possibly as a consequence of a greater investment in membrane-bound protein. Invasive species may succeed by employing a wide range of N allocation mechanisms, including higher amino acid production for fast growth under high irradiance or storage of N in leaves as soluble protein or amino acids. PMID:23700483

  1. Photosynthetic, antioxidative, molecular and ultrastructural responses of young cacao plants to Cd toxicity in the soil.

    Science.gov (United States)

    Pereira de Araújo, Romária; Furtado de Almeida, Alex-Alan; Silva Pereira, Lidiane; Mangabeira, Pedro A O; Olimpio Souza, José; Pirovani, Carlos P; Ahnert, Dário; Baligar, Virupax C

    2017-10-01

    Cadmium (Cd) is a highly toxic metal for plants, even at low concentrations in the soil. The annual production of world cocoa beans is approximately 4 million tons. Most of these fermented and dried beans are used in the manufacture of chocolate. Recent work has shown that the concentration of Cd in these beans has exceeded the critical level (0.6mgkg -1 DM). The objective of this study was to evaluate the toxicity of Cd in young plants of CCN 51 cacao genotype grown in soil with different concentrations of Cd (0, 0.05 and 0.1gkg -1 soil) through photosynthetic, antioxidative, molecular and ultrastructural changes. The increase of Cd concentration in the soil altered mineral nutrient absorption by competition or synergism, changed photosynthetic activity caused by reduction in chloroplastidic pigment content and damage to the photosynthetic machinery evidenced by the Fv/Fm ratio and expression of the psbA gene and increased GPX activity in the root and SOD in leaves. Additionally, ultrastructural alterations in roots and leaves were also evidenced with the increase of the concentration of Cd in the soil, whose toxicity caused rupture of biomembranes in root and leaf cells, reduction of the number of starch grains in foliar cells, increase of plastoglobules in chloroplasts and presence of multivesiculated bodies in root cells. It was concluded, therefore, that soil Cd toxicity caused damage to the photosynthetic machinery, antioxidative metabolism, gene expression and irreversible damage to root cells ultrastructure of CCN 51 cocoa plants, whose damage intensity depended on the exposure time to the metal. Copyright © 2017. Published by Elsevier Inc.

  2. Direct and selective small-molecule inhibition of photosynthetic PEP carboxylase: New approach to combat C4 weeds in arable crops.

    Science.gov (United States)

    Paulus, Judith Katharina; Förster, Kerstin; Groth, Georg

    2014-06-05

    Phosphoenolpyruvate carboxylase (PEPC) is a key enzyme of C4 photosynthesis. Besides, non-photosynthetic isoforms of PEPC are found in bacteria and all types of plants, although not in animals or fungi. A single residue in the allosteric feedback inhibitor site of PEPC was shown to adjust the affinity of the photosynthetic and non-photosynthetic isoforms for feedback inhibition by metabolites of the C4 pathway. Here, we applied computational screening and biochemical analyses to identify molecules that selectively inhibit C4 PEPC, but have no effect on the activity of non-photosynthetic PEPCs. We found two types of selective inhibitors, catechins and quinoxalines. Binding constants in the lower μM range and a strong preference for C4 PEPC qualify the quinoxaline compounds as potential selective herbicides to combat C4 weeds. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  3. Physical activity and incident type 2 diabetes mellitus: a systematic review and dose-response meta-analysis of prospective cohort studies.

    Science.gov (United States)

    Smith, Andrea D; Crippa, Alessio; Woodcock, James; Brage, Søren

    2016-12-01

    Inverse associations between physical activity (PA) and type 2 diabetes mellitus are well known. However, the shape of the dose-response relationship is still uncertain. This review synthesises results from longitudinal studies in general populations and uses non-linear models of the association between PA and incident type 2 diabetes. A systematic literature search identified 28 prospective studies on leisure-time PA (LTPA) or total PA and risk of type 2 diabetes. PA exposures were converted into metabolic equivalent of task (MET) h/week and marginal MET (MMET) h/week, a measure only considering energy expended above resting metabolic rate. Restricted cubic splines were used to model the exposure-disease relationship. Our results suggest an overall non-linear relationship; using the cubic spline model we found a risk reduction of 26% (95% CI 20%, 31%) for type 2 diabetes among those who achieved 11.25 MET h/week (equivalent to 150 min/week of moderate activity) relative to inactive individuals. Achieving twice this amount of PA was associated with a risk reduction of 36% (95% CI 27%, 46%), with further reductions at higher doses (60 MET h/week, risk reduction of 53%). Results for the MMET h/week dose-response curve were similar for moderate intensity PA, but benefits were greater for higher intensity PA and smaller for lower intensity activity. Higher levels of LTPA were associated with substantially lower incidence of type 2 diabetes in the general population. The relationship between LTPA and type 2 diabetes was curvilinear; the greatest relative benefits are achieved at low levels of activity, but additional benefits can be realised at exposures considerably higher than those prescribed by public health recommendations.

  4. Risk of incident active tuberculosis disease in patients treated with non-steroidal anti-inflammatory drugs: a population-based study.

    Science.gov (United States)

    Wu, Chun-Wei; Wu, Jiunn-Yih; Lee, Meng-Tse Gabriel; Lai, Chih-Cheng; Wu, I-Lin; Tsai, Yi-Wen; Chang, Shy-Shin; Lee, Chien-Chang

    2017-05-04

    Mycobacterium tuberculosis (TB) is one of the world's most devastating public health threats. Our goal is to evaluate whether the use of non-steroidal anti-inflammatory drugs (NSAIDs) affect the risk of new incident active TB disease. We conducted a nested case-control analysis by using a 1 million longitudinally followed cohort, from Taiwan's national health insurance research database. Effects of NSAIDs on active TB were estimated by conditional logistic regression and adjusted using a TB-specific disease risk score (DRS). NSAIDs exposures were defined as having a prescription record of NSAIDs ≧ 7 days that ended between 31 and 90 days prior to the index date. A total of 123,419 users of traditional NSAIDs, 16,392 users of cyclooxygenase-2 selective inhibitor (Coxibs), and 4706 incident cases of active TB were identified. Compared with nonusers, use of traditional NSAIDs was associated with an increased risk of TB in the unadjusted analysis ([RR], 1.39; 95% [CI], 1.24 - 1.57 and DRS adjusted analysis ([ARR], 1.30; 95% [CI], 1.15- 1.47). However, use of Coxibs was not associated with a significant increase in the risk of TB after DRS adjustment ([ARR], 1.23; 95% [CI], 0.89 - 1.70). In this large population-based study, we found that subjects using traditional NSAIDs were associated with increased risk for active TB. We did not find evidence for a causative mechanism between traditional NSAIDs and TB, and more research is required to verify whether the association between traditional NSAIDs and TB is causal, or simply reflects an increased use of anti-inflammatory drugs in the early phases of TB onset.

  5. Photosynthetic limitation and mechanisms of photoprotection under drought and recovery of Calotropis procera, an evergreen C3 from arid regions.

    Science.gov (United States)

    Rivas, Rebeca; Frosi, Gabriella; Ramos, Diego G; Pereira, Silvia; Benko-Iseppon, Ana M; Santos, Mauro G

    2017-09-01

    Calotropis procera is a C 3 plant native from arid environmental zones. It is an evergreen, shrubby, non-woody plant with intense photosynthetic metabolism during the dry season. We measured photosynthetic parameters and leaf biochemical traits, such as gas exchange, photochemical parameters, A/C i analysis, organic solutes, and antioxidant enzymes under controlled conditions in potted plants during drought stress, and following recovery conditions to obtain a better insight in the drought stress responses of C. procera. Indeed, different processes contribute to the drought stress resilience of C. procera and to the fast recovery after rehydration. The parameters analyzed showed that C. procera has a high efficiency for energy dissipation. The photosynthetic machinery is protected by a robust antioxidant system and photoprotective mechanisms such as alternative pathways for electrons (photorespiration and day respiration). Under severe drought stress, increased stomatal limitation and decreased biochemical limitation permitted C. procera to maintain maximum rate of Rubisco carboxylation (V c,max ) and photosynthetic rate (A max ). On the other hand, limitation of stomatal or mesophyll CO 2 diffusion did not impair fast recovery, maintaining V c,max , chloroplast CO 2 concentration (C c ) and mesophyll conductance (g m ) unchanged while electron flow used for RuBP carboxylation (J c ) and A max increased. The ability to tolerate drought stress and the fast recovery of this evergreen C 3 species was also due to leaf anti-oxidative stress enzyme activity, and photosynthetic pigments. Thus, these different drought tolerance mechanisms allowed high performance of photosynthetic metabolism by drought stressed plants during the re-watering period. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  6. Leaf-level photosynthetic capacity in lowland Amazonian and high-elevation Andean tropical moist forests of Peru.

    Science.gov (United States)

    Bahar, Nur H A; Ishida, F Yoko; Weerasinghe, Lasantha K; Guerrieri, Rossella; O'Sullivan, Odhran S; Bloomfield, Keith J; Asner, Gregory P; Martin, Roberta E; Lloyd, Jon; Malhi, Yadvinder; Phillips, Oliver L; Meir, Patrick; Salinas, Norma; Cosio, Eric G; Domingues, Tomas F; Quesada, Carlos A; Sinca, Felipe; Escudero Vega, Alberto; Zuloaga Ccorimanya, Paola P; Del Aguila-Pasquel, Jhon; Quispe Huaypar, Katherine; Cuba Torres, Israel; Butrón Loayza, Rosalbina; Pelaez Tapia, Yulina; Huaman Ovalle, Judit; Long, Benedict M; Evans, John R; Atkin, Owen K

    2017-05-01

    We examined whether variations in photosynthetic capacity are linked to variations in the environment and/or associated leaf traits for tropical moist forests (TMFs) in the Andes/western Amazon regions of Peru. We compared photosynthetic capacity (maximal rate of carboxylation of Rubisco (V cmax ), and the maximum rate of electron transport (J max )), leaf mass, nitrogen (N) and phosphorus (P) per unit leaf area (M a , N a and P a , respectively), and chlorophyll from 210 species at 18 field sites along a 3300-m elevation gradient. Western blots were used to quantify the abundance of the CO 2 -fixing enzyme Rubisco. Area- and N-based rates of photosynthetic capacity at 25°C were higher in upland than lowland TMFs, underpinned by greater investment of N in photosynthesis in high-elevation trees. Soil [P] and leaf P a were key explanatory factors for models of area-based V cmax and J max but did not account for variations in photosynthetic N-use efficiency. At any given N a and P a , the fraction of N allocated to photosynthesis was higher in upland than lowland species. For a small subset of lowland TMF trees examined, a substantial fraction of Rubisco was inactive. These results highlight the importance of soil- and leaf-P in defining the photosynthetic capacity of TMFs, with variations in N allocation and Rubisco activation state further influencing photosynthetic rates and N-use efficiency of these critically important forests. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  7. Comparison of electrochemical performances and microbial community structures of two photosynthetic microbial fuel cells.

    Science.gov (United States)

    Zheng, Wei; Cai, Teng; Huang, Manhong; Chen, Donghui

    2017-11-01

    Microbial fuel cells (MFCs) have attracted intensive interest for their power generation and pollutants removal characteristics. Electrochemical performances and community structures of two algae cathode photosynthetic MFCs were investigated and compared. Microbial consortia of these two MFCs were taken from wetland sediment (named SMFC) and an up-flow anaerobic wastewater treatment reactor (named UMFC). Maximum power density of the SMFC and UMFC achieved 202.9 ± 18.1 mW/m 2 and 158.2±15.1 mW/m 2 , respectively. The SMFC displayed higher columbic efficiency but lower chemical oxygen demand (COD) removal efficiency than that of UMFC. The results also revealed the addition of riboflavin (RF) and neutral red (NR) decreased the redox current of the SMFC but promoted that of UMFC. Community structure analysis showed the SMFC was dominated by photosynthetic genus Rhodopseudomonas (61.25%), while bacterial genera in the UMFC were more evenly distributed. The difference of electrochemical activities of the two MFCs was caused by the different roles of exoelectrogens such as Rhodopseudomonas spp. and Citrobacter spp. in the electron transfer process. Newly developed photosynthetic microbial fuel cells (PMFCs) provide a suitable process to generate power and remove pollutants. The consortia have a significant role in the performance and microbial community of the system. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  8. A new perspective on hydrogen production by photosynthetic water-splitting

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.W.; Greenbaum, E.

    1996-05-01

    Present energy systems are heavily dependent on fossil fuels. This will eventually lead to the foreseeable depletion of fossil energy resources and, according to some reports, global climate changes due to the emission of carbon dioxide. In principle, hydrogen production by biophotolysis of water can be an ideal solar energy conversion system for sustainable development of human activities in harmony with the global environment. In photosynthetic hydrogen production research, there are currently two main efforts: (1) Direct photoevolution of hydrogen and oxygen by photosynthetic water splitting using the ferredoxin/hydrogenase pathway; (2) Dark hydrogen production by fermentation of organic reserves such as starch that are generated by photosynthesis during the light period. In this chapter, the advantages and challenges of the two approaches for hydrogen production will be discussed, in relation to a new opportunity brought by our recent discovery of a new photosynthetic water-splitting reaction which, potentially, has twice the energy efficiency of conventional watersplitting via the two light reaction Z-scheme of photosynthesis.

  9. [Effects of different LED light qualities on photosynthetic characteristics, fruit production and quality of strawberry].

    Science.gov (United States)

    Liu, Qing; Lian, Hai-feng; Liu, Shi-qi; Sun, Ya-li; Yu, Xin-hui; Guo, Hui-ping

    2015-06-01

    Taking 'Miaoxiang No.7' strawberry as material, full red light, full blue light, full yellow light, full white light, red/blue/yellow (7/2/1), red/blue (7/2) light generated by light emitting diode (LED) was applied to accurately modulate with white light generated as control. The indicators of photosynthetic and fluorescence parameters, pigment content, fruit production and quality, root activity were investigated. The effects of light quality under the light intensity (500 µmol · m(-2) · s(-1)) on the photosynthetic characteristic, fruit production and quality of strawberry were studied. The results showed that the red light could increase photosynthetic parameters (Pn, Tr), while blue light had inhibitory effect. Intercellular CO2 concentration (Ci) and conductance (g(s)) were the highest under blue light. The fluorescence parameters were significantly affected by light quality, Fo, Fm and Φ PS II the highest under red light, but values of the maximal photochemical of PS II (Fv/Fm), Fv/Fo and Fm/Fo highest under red/blue/yellow (7/2/1). In addition, the soluble solids content and vitamin C were highest under red light, the blue light could increase protein and titratable acid, sugar-acid ratio was the highest under red/blue/yellow (7/2/1). Comprehensive analysis indicated that red/blue/yellow (7/2/1) was more beneficial to the increase of pigment contents of leaves, fruit production and some qualities of strawberry.

  10. Introducing extra NADPH consumption ability significantly increases the photosynthetic efficiency and biomass production of cyanobacteria.

    Science.gov (United States)

    Zhou, Jie; Zhang, Fuliang; Meng, Hengkai; Zhang, Yanping; Li, Yin

    2016-11-01

    Increasing photosynthetic efficiency is crucial to increasing biomass production to meet the growing demands for food and energy. Previous theoretical arithmetic analysis suggests that the light reactions and dark reactions are imperfectly coupled due to shortage of ATP supply, or accumulation of NADPH. Here we hypothesized that solely increasing NADPH consumption might improve the coupling of light reactions and dark reactions, thereby increasing the photosynthetic efficiency and biomass production. To test this hypothesis, an NADPH consumption pathway was constructed in cyanobacterium Synechocystis sp. PCC 6803. The resulting extra NADPH-consuming mutant grew much faster and achieved a higher biomass concentration. Analyses of photosynthesis characteristics showed the activities of photosystem II and photosystem I and the light saturation point of the NADPH-consuming mutant all significantly increased. Thus, we demonstrated that introducing extra NADPH consumption ability is a promising strategy to increase photosynthetic efficiency and to enable utilization of high-intensity lights. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  11. Photosynthetic performance of a helical tubular photobioreactor incorporating the cyanobacterium Spirulina platensis

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Yoshitomo; Hall, D.O. [Univ. of London (United Kingdom); Nouee, J. De La [Univ. Laval, Quebec City, Quebec (Canada). Dept. of Food Science and Technology

    1995-07-20

    The photosynthetic performance of a helical tubular photobioreactor (``Biocoil``), incorporating the filamentous cyanobacterium Spirulina platensis, was investigated. The photobioreactor was constructed in a cylindrical shape with a 0.25-m{sup 2} basal area and a photostage comprising 60 m of transparent PVC tubing of 1.6-cm inner diameter. The inner surface of the cylinder was illuminated with cool white fluorescent lamps; the energy input of photosynthetically active radiation into the photobioreactor was 2,920 kJ per day. An air-lift system incorporating 4% CO{sub 2} was used to circulate the growth medium in the tubing. The maximum productivity achieved in batch culture was 7.18 g dry biomass per day which corresponded to a photosynthetic (PAR) efficiency of 5.45%. The CO{sub 2} was efficiently removed from the gaseous stream; monitoring the CO{sub 2} in the outlet and inlet gas streams showed a 70% removal of CO{sub 2} from the inlet gas over an 8-h period with almost maximum growth rate.

  12. Physical activity, smoking, and alcohol consumption in association with incidence of type 2 diabetes among middle-aged and elderly Chinese men.

    Directory of Open Access Journals (Sweden)

    Liang Shi

    Full Text Available Type 2 diabetes mellitus (T2DM is a prevalent chronic disease worldwide. The prevalence of T2DM is increasing rapidly in China. Understanding the contribution of modifiable lifestyle factors on T2DM risk is imperative to prevent the development of T2DM in China.We examined associations between lifestyle factors including physical activity, smoking and alcohol consumption with incidence of T2DM among middle-aged and elderly men in urban Shanghai. Information on socio-demographics, lifestyle habits, dietary habits, and disease history was collected via in-person interviews. Anthropometric measurements were taken. A total of 51 464 Chinese men aged 40-74 years free of T2DM, coronary heart disease (CHD, and stroke at baseline were included in the current study. Incident T2DM was identified through follow-up surveys conducted every 2-3 years. Cox proportional hazard analyses were conducted to evaluate associations between lifestyle risk factors and incidence of T2DM.We documented 1304 new cases of T2DM during 276 929 person-years of follow-up (average: 5.4 years. Physical activity was inversely associated with T2DM risk. Daily living, commuting, and total physical activity METs had inverse negative dose-response relationships with T2DM (P-trend = 0.0033, 0.0022, and <0.0001, respectively. Regular participation in exercise or sports reduced T2DM risk (HR = 0.86, 95%CI: 0.76-0.98. Moderate alcohol intake (1-3 drinks/day was inversely related to T2DM risk (HR = 0.80, 95%CI: 0.67-0.94. Cigarette smoking, on the other hand, was associated with increased T2DM risk; HRs were 1.25 (95%CI: 1.00-1.56 for smoking more than 20 cigarettes per day and 1.28 (95%CI: 1.04-1.57 for smoking more than 40 pack-years.Physical activity and moderate alcohol intake are inversely associated with T2DM risk, whereas smoking was positively associated with T2DM risk among middle-age and elderly Chinese men. Preventive measures should be developed to focus on these modifiable

  13. Association of Ferredoxin:NADP+ oxidoreductase with the photosynthetic apparatus modulates electron transfer in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Mosebach, Laura; Heilmann, Claudia; Mutoh, Risa; Gäbelein, Philipp; Steinbeck, Janina; Happe, Thomas; Ikegami, Takahisa; Hanke, Guy; Kurisu, Genji; Hippler, Michael

    2017-12-01

    Ferredoxins (FDX) and the FDX:NADP + oxidoreductase (FNR) represent a key junction of electron transport downstream of photosystem I (PSI). Dynamic recruitment of FNR to the thylakoid membrane has been considered as a potential mechanism to define the fate of photosynthetically derived electrons. In this study, we investigated the functional importance of the association of FNR with the photosynthetic apparatus in Chlamydomonas reinhardtii. In vitro assays based on NADP + photoreduction measurements as well as NMR chemical shift perturbation analyses showed that FNR preferentially interacts with FDX1 compared to FDX2. Notably, binding of FNR to a PSI supercomplex further enhanced this preference for FDX1 over FDX2, suggesting that FNR is potentially capable of channelling electrons towards distinct routes. NADP + photoreduction assays and immunoblotting revealed that the association of FNR with the thylakoid membrane including the PSI supercomplex is impaired in the absence of Proton Gradient Regulation 5 (PGR5) and/or Proton Gradient Regulation 5-Like photosynthetic phenotype 1 (PGRL1), implying that both proteins, directly or indirectly, contribute to the recruitment of FNR to the thylakoid membrane. As assessed via in vivo absorption spectroscopy and immunoblotting, PSI was the primary target of photodamage in response to high-light stress in the absence of PGR5 and/or PGRL1. Anoxia preserved the activity of PSI, pointing to enhanced electron donation to O 2 as the source of the observed PSI inactivation and degradation. These findings establish another perspective on PGR5/PGRL1 knockout-related phenotypes and potentially interconnect FNR with the regulation of photosynthetic electron transport and PSI photoprotection in C. reinhardtii.

  14. Photosynthetic performance in Sphagnum transplanted along a latitudinal nitrogen deposition gradient.

    Science.gov (United States)

    Granath, Gustaf; Strengbom, Joachim; Breeuwer, Angela; Heijmans, Monique M P D; Berendse, Frank; Rydin, Håkan

    2009-04-01

    Increased N deposition in Europe has affected mire ecosystems. However, knowledge on the physiological responses is poor. We measured photosynthetic responses to increasing N deposition in two peatmoss species (Sphagnum balticum and Sphagnum fuscum) from a 3-year, north-south transplant experiment in northern Europe, covering a latitudinal N deposition gradient ranging from 0.28 g N m(-2) year(-1) in the north, to 1.49 g N m(-2) year(-1) in the south. The maximum photosynthetic rate (NP(max)) increased southwards, and was mainly explained by tissue N concentration, secondly by allocation of N to the photosynthesis, and to a lesser degree by modified photosystem II activity (variable fluorescence/maximum fluorescence yield). Although climatic factors may have contributed, these results were most likely attributable to an increase in N deposition southwards. For S. fuscum, photosynthetic rate continued to increase up to a deposition level of 1.49 g N m(-2) year(-1), but for S. balticum it seemed to level out at 1.14 g N m(-2) year(-1). The results for S. balticum suggested that transplants from different origin (with low or intermediate N deposition) respond differently to high N deposition. This indicates that Sphagnum species may be able to adapt or physiologically adjust to high N deposition. Our results also suggest that S. balticum might be more sensitive to N deposition than S. fuscum. Surprisingly, NP(max) was not (S. balticum), or only weakly (S. fuscum) correlated with biomass production, indicating that production is to a great extent is governed by factors other than the photosynthetic capacity.

  15. Sensitivity of the green algae Chlamydomonas reinhardtii to gamma radiation: Photosynthetic performance and ROS formation

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Tânia, E-mail: tania.gomes@niva.no [Norwegian Institute for Water Research (NIVA), Section of Ecotoxicology and Risk Assessment, Gaustadalléen 21, N-0349, Oslo (Norway); Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432 Ås (Norway); Xie, Li [Norwegian Institute for Water Research (NIVA), Section of Ecotoxicology and Risk Assessment, Gaustadalléen 21, N-0349, Oslo (Norway); Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432 Ås (Norway); Brede, Dag; Lind, Ole-Christian [Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432 Ås (Norway); Department for Environmental Sciences, Faculty of Environmental Science & Technology, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432, Ås (Norway); Solhaug, Knut Asbjørn [Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432 Ås (Norway); Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences (NMBU), Postbox 5003, N-1432, Ås (Norway); Salbu, Brit [Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432 Ås (Norway); Department for Environmental Sciences, Faculty of Environmental Science & Technology, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432, Ås (Norway); and others

    2017-02-15

    Highlights: • Chlorophyll fluorescence parameters affected at higher dose rates. • Changes in PSII associated with electron transport and energy dissipation pathways. • Dose-dependent ROS production in algae exposed to gamma radiation. • Decrease in photosynthetic efficiency connected to ROS formation. - Abstract: The aquatic environment is continuously exposed to ionizing radiation from both natural and anthropogenic sources, making the characterization of ecological and health risks associated with radiation of large importance. Microalgae represent the main source of biomass production in the aquatic ecosystem, thus becoming a highly relevant biological model to assess the impacts of gamma radiation. However, little information is available on the effects of gamma radiation on microalgal species, making environmental radioprotection of this group of species challenging. In this context, the present study aimed to improve the understanding of the effects and toxic mechanisms of gamma radiation in the unicellular green algae Chlamydomonas reinhardtii focusing on the activity of the photosynthetic apparatus and ROS formation. Algal cells were exposed to gamma radiation (0.49–1677 mGy/h) for 6 h and chlorophyll fluorescence parameters obtained by PAM fluorometry, while two fluorescent probes carboxy-H{sub 2}DFFDA and DHR 123 were used for the quantification of ROS. The alterations seen in functional parameters of C. reinhardtii PSII after 6 h of exposure to gamma radiation showed modifications of PSII energy transfer associated with electron transport and energy dissipation pathways, especially at the higher dose rates used. Results also showed that gamma radiation induced ROS in a dose-dependent manner under both light and dark conditions. The observed decrease in photosynthetic efficiency seems to be connected to the formation of ROS and can potentially lead to oxidative stress and cellular damage in chloroplasts. To our knowledge, this is the first

  16. How oxygen attacks [FeFe] hydrogenases from photosynthetic organisms

    Science.gov (United States)

    Stripp, Sven T.; Goldet, Gabrielle; Brandmayr, Caterina; Sanganas, Oliver; Vincent, Kylie A.; Haumann, Michael; Armstrong, Fraser A.; Happe, Thomas

    2009-01-01

    Green algae such as Chlamydomonas reinhardtii synthesize an [FeFe] hydrogenase that is highly active in hydrogen evolution. However, the extreme sensitivity of [FeFe] hydrogenases to oxygen presents a major challenge for exploiting these organisms to achieve sustainable photosynthetic hydrogen production. In this study, the mechanism of oxygen inactivation of the [FeFe] hydrogenase CrHydA1 from C. reinhardtii has been investigated. X-ray absorption spectroscopy shows that reaction with oxygen results in destruction of the [4Fe-4S] domain of the active site H-cluster while leaving the di-iron domain (2FeH) essentially intact. By protein film electrochemistry we were able to determine the order of events leading up to this destruction. Carbon monoxide, a competitive inhibitor of CrHydA1 which binds to an Fe atom of the 2FeH domain and is otherwise not known to attack FeS clusters in proteins, reacts nearly two orders of magnitude faster than oxygen and protects the enzyme against oxygen damage. These results therefore show that destruction of the [4Fe-4S] cluster is initiated by binding and reduction of oxygen at the di-iron domain—a key step that is blocked by carbon monoxide. The relatively slow attack by oxygen compared to carbon monoxide suggests that a very high level of discrimination can be achieved by subtle factors such as electronic effects (specific orbital overlap requirements) and steric constraints at the active site. PMID:19805068

  17. An evaluation of the effects of exogenous ethephon, an ethylene releasing compound, on photosynthesis of mustard (Brassica juncea cultivars that differ in photosynthetic capacity

    Directory of Open Access Journals (Sweden)

    Khan NA

    2004-12-01

    Full Text Available Abstract Background The stimulatory effect of CO2 on ethylene evolution in plants is known, but the extent to which ethylene controls photosynthesis is not clear. Studies on the effects of ethylene on CO2 metabolism have shown conflicting results. Increase or inhibition of photosynthesis by ethylene has been reported. To understand the physiological processes responsible for ethylene-mediated changes in photosynthesis, stomatal and mesophyll effects on photosynthesis and ethylene biosynthesis in response to ethephon treatment in mustard (Brassica juncea cultivars differing in photosynthetic capacity were studied. Results The effects of ethephon on photosynthetic rate (PN, stomatal conductance (gS, carbonic anhydrase (CA activity, 1-aminocyclopropane carboxylic acid synthase (ACS activity and ethylene evolution were similar in both the cultivars. Increasing ethephon concentration up to 1.5 mM increased PN, gS and CA maximally, whereas 3.0 mM ethephon proved inhibitory. ACS activity and ethylene evolution increased with increasing concentrations of ethephon. The corresponding changes in gs and CA activity suggest that the changes in photosynthesis in response to ethephon were triggered by altered stomatal and mesophyll processes. Stomatal conductance changed in parallel with changes in mesophyll photosynthetic properties. In both the cultivars ACS activity and ethylene increased up to 3.0 mM ethephon, but 1.5 mM ethephon caused maximum effects on photosynthetic parameters. Conclusion These results suggest that ethephon affects foliar gas exchange responses. The changes in photosynthesis in response to ethephon were due to stomatal and mesophyll effects. The changes in gS were a response maintaining stable intercellular CO2 concentration (Ci under the given treatment in both the cultivars. Also, the high photosynthetic capacity cultivar, Varuna responded less to ethephon than the low photosynthetic capacity cultivar, RH30. The photosynthetic

  18. Incidence of Opportunistic Infections among HIV-Positive Adults on Highly Active Antiretroviral Therapy in a Teaching Hospital, India: Prospective Study.

    Science.gov (United States)

    Shenoy, Nandita; Ramapuram, John T; Shenoy, Ashok; Ahmed, Junaid; Srikant, N

    Oral manifestations in HIV infections are numerous and some of these are acknowledged as being of great importance in the early diagnosis of the disease. Many HIV-associated oral infections occur early in HIV disease, not infrequently as the presenting sign or symptom. Thus, early detection of the associated oral opportunistic infections should, in many cases, result in earlier diagnosis of HIV infection. Cytology, a simple, painless, and inexpensive method, has become a preferred method and was used in our study for early diagnosis of certain lesions. To determine the effect of highly active antiretroviral therapy on incidence rate of opportunistic infections among HIV-positive adults in a teaching hospital in India, a prospective study was conducted and the required sample size was 40. Study participants were selected randomly from the outpatient department of an HIV clinic who were currently on for antiretroviral therapy (ART). Data on age, gender, form of contagion, antiretroviral therapy at the time of review, number of CD4 lymphocytes per milliliter, and viral load were collected. Oral cytologic investigation was carried out and then stained for histopathological examination. A total of 40 individuals were examined and the incidence of opportunistic infections was 66.7% in individuals with CD4 counts less than 200, 55.6% in individuals with CD4 counts of 200 to 499, and 40.0% in individuals with CD4 counts more than 500. The incidence of opportunistic infection was higher in individuals with low CD4 counts in spite of being on ART.

  19. Carotenoid Photoprotection in Artificial Photosynthetic Antennas

    Energy Technology Data Exchange (ETDEWEB)

    Kloz, Miroslav [VU Univ., Amsterdam (Netherlands); Pillai, Smitha [Arizona State Univ., Tempe, AZ (United States); Kodis, Gerdenis [Arizona State Univ., Tempe, AZ (United States); Gust, Devens [Arizona State Univ., Tempe, AZ (United States); Moore, Thomas A. [Arizona State Univ., Tempe, AZ (United States); Moore, Ana L. [Arizona State Univ., Tempe, AZ (United States); van Grondelle, Rienk [VU Univ., Amsterdam (Netherlands); Kennis, John T. M. [VU Univ., Amsterdam (Netherlands)

    2011-04-14

    . These synthetic systems are providing a deeper understanding of structural and environmental effects on the interactions between carotenoids and tetrapyrroles and thereby better defining their role in controlling natural photosynthetic systems.

  20. Growth and photosynthetic responses of wheat plants grown in space.

    Science.gov (United States)

    Tripathy, B C; Brown, C S; Levine, H G; Krikorian, A D

    1996-03-01

    Growth and photosynthesis of wheat (Triticum aestivum L. cv Super Dwarf) plants grown onboard the space shuttle Discovery for 10 d were examined. Compared to ground control plants, the shoot fresh weight of space-grown seedlings decreased by 25%. Postflight measurements of the O2 evolution/photosynthetic photon flux density response curves of leaf samples revealed that the CO2-saturated photosynthetic rate at saturating light intensities in space-grown plants declined 25% relative to the rate in ground control plants. The relative quantum yield of CO2-saturated photosynthetic O2 evolution measured at limiting light intensities was not significantly affected. In space-grown plants, the light compensation point of the leaves increased by 33%, which likely was due to an increase (27%) in leaf dark-respiration rates. Related experiments with thylakoids isolated from space-grown plants showed that the light-saturated photosynthetic electron transport rate from H2O through photosystems II and I was reduced by 28%. These results demonstrate that photosynthetic functions are affected by the microgravity environment.

  1. Species-Specific Associations Between Bacterioplankton and Photosynthetic Picoeukaryotes

    Science.gov (United States)

    Farnelid, H.; Turk-Kubo, K.; Zehr, J. P.

    2016-02-01

    Photosynthetic picoeukaryotes are significant contributors to marine primary productivity. Interactions between marine bacterioplankton and picoeukaryotes frequently occur and can have large biogeochemical impacts. Currently, partly due to methodological difficulties for studying microbial associations in situ, these ecological interactions are poorly characterized. Here we use flow cytometry sorting to identify novel bacterial phylotypes found in physical association with photosynthetic picoeukaryotes. Samples were collected on eight occasions at the Santa Cruz wharf on Monterey Bay during summer and fall, 2014. The phylogeny of associated microbes was assessed through clone libraries and Illumina MiSeq sequencing of amplicons of the 16S rRNA gene. In addition, 16 bacterial isolates comprised of 14 taxa were obtained from sorted photosynthetic picoeukaryote cells. The most frequently detected bacterioplankton phyla were Alphaproteobacteria, Bacteriodetes, and Gammaproteobacteria. The sequences from the sorted populations were a community distinct from the unsorted seawater samples suggesting species-specific functional associations. These species-specific patterns were further supported by re-occurring patterns between replicates and sampling dates. The finding of sequences from the free-living genera Synechococcus and Pelagibacter also suggest that photosynthetic picoeukaryotes can be bacterivores, possibly feeding on some of the most numerically abundant bacteria. The results show that specific bacterial phylotypes are found in association with photosynthetic picoeukaryotes. Taxonomic identification of these associations is a prerequisite for further characterizing the interactions, their metabolic pathways and ecological functions.

  2. Effect of trypsin inhibitor activity in soya bean on growth performance, protein digestibility and incidence of sub-clinical necrotic enteritis in broiler chicken flocks.

    Science.gov (United States)

    Palliyeguru, M W C D; Rose, S P; Mackenzie, A M

    2011-06-01

    1. The effect of three different levels of dietary trypsin inhibitor activity (achieved by varying the amount of non-toasted full fat soya bean in replacement for toasted full fat soya bean) on the incidence of spontaneously-occurring sub-clinical necrotic enteritis (NE) in broiler chickens was compared. A fourth dietary treatment compared the effect of a diet that used potato protein concentrate as the major protein source. The determined trypsin inhibitor activity increased with the increasing content of non-toasted soya bean: 1·90, 6·21, 8·46 and 3·72 mg/g for the three soya bean diets (0, 100 and 200 g of non-toasted soya bean/kg) and the potato protein diet respectively. 2. Although increasing amounts of the non-toasted full-fat soya bean increased the feed intakes of the birds, there was a marked reduction in protein digestibility, weight gain and feed conversion efficiency. 3. There was a linear increase in sub-clinical NE lesions in the duodenum, jejunum, mid small intestine and ileum with increasing non-toasted soya bean. Caecal Clostridium perfringens counts increased with the increasing dietary content of non-toasted soya bean. Serum α-toxin antibodies were higher in the birds fed the 200 g non-toasted soya bean/kg diet compared with the other diets. 4. The results demonstrated that variation in the amount of non-toasted dietary soya bean not only affects growth performance of broilers but also affects the incidence of sub-clinical necrotic enteritis in the flock. Ensuring the lowest possible trypsin-inhibitor activity in soya bean samples is a valuable tool to improve the health and welfare of birds and in reducing the financial losses from this disease.

  3. Impacts of Saharan dust on downward irradiance and photosynthetically available radiation in the water column

    Directory of Open Access Journals (Sweden)

    T. Ohde

    2012-09-01

    Full Text Available A semi-empirical approach was used to quantify the modification of the underwater light field in amplitude (magnitude effect and spectral distribution (spectral effect by different atmospheric conditions altering the incident light. The approach based on an optical model in connection with radiation measurements in the area off Northwest Africa. Key inputs of the model were parameterized magnitude and spectral effects. Various atmospheric conditions were considered: clear sky, dusty sky without clouds, cloudy sky without dust and skies with different ratios of dust and clouds. Their impacts were investigated concerning the modification of the downward irradiance and photosynthetically available radiation in the water column. The impact on downward irradiance depended on the wavelength, the water depth, the optical water properties, the dust and cloud properties, and the ratio of clouds to dust. The influence of clouds on the amplitude can be much higher than that of dust. Saharan dust reduced the photosynthetically available radiation in the water column. Ocean regions were more influenced than coastal areas. Compensations of the magnitude and spectral effects were observed at special water depths in ocean regions and at atmospheric conditions with definite cloud to dust ratios.

  4. Stomatal kinetics and photosynthetic gas exchange along a continuum of isohydric to anisohydric regulation of plant water status.

    Science.gov (United States)

    Meinzer, Frederick C; Smith, Duncan D; Woodruff, David R; Marias, Danielle E; McCulloh, Katherine A; Howard, Ava R; Magedman, Alicia L

    2017-08-01

    Species' differences in the stringency of stomatal control of plant water potential represent a continuum of isohydric to anisohydric behaviours. However, little is known about how quasi-steady-state stomatal regulation of water potential may relate to dynamic behaviour of stomata and photosynthetic gas exchange in species operating at different positions along this continuum. Here, we evaluated kinetics of light-induced stomatal opening, activation of photosynthesis and features of quasi-steady-state photosynthetic gas exchange in 10 woody species selected to represent different degrees of anisohydry. Based on a previously developed proxy for the degree of anisohydry, species' leaf water potentials at turgor loss, we found consistent trends in photosynthetic gas exchange traits across a spectrum of isohydry to anisohydry. More anisohydric species had faster kinetics of stomatal opening and activation of photosynthesis, and these kinetics were closely coordinated within species. Quasi-steady-state stomatal conductance and measures of photosynthetic capacity and performance were also greater in more anisohydric species. Intrinsic water-use efficiency estimated from leaf gas exchange and stable carbon isotope ratios was lowest in the most anisohydric species. In comparisons between gas exchange traits, species rankings were highly consistent, leading to species-independent scaling relationships over the range of isohydry to anisohydry observed. © 2017 John Wiley & Sons Ltd.

  5. A double-edged sword: does highly active antiretroviral therapy contribute to syphilis incidence by impairing immunity toTreponema pallidum?

    Science.gov (United States)

    Rekart, Michael L; Ndifon, Wilfred; Brunham, Robert C; Dushoff, Jonathan; Park, Sang Woo; Rawat, Sanjana; Cameron, Caroline E

    2017-08-01

    Recently, the world has experienced a rapidly escalating outbreak of infectious syphilis primarily affecting men who have sex with men (MSM); many are taking highly active antiretroviral therapy (HAART) for HIV-1 infection. The prevailing hypothesis is that HAART availability and effectiveness have led to the perception among both individuals who are HIV-1 infected and those who are uninfected that HIV-1 transmission has become much less likely, and the effects of HIV-1 infection less deadly. This is expected to result in increased sexual risk-taking, especially unprotected anal intercourse, leading to more non-HIV-1 STDs, including gonorrhoea, chlamydia and syphilis. However, syphilis incidence has increased more rapidly than other STDs. We hypothesise that HAART downregulates the innate and acquired immune responses to Treponema pallidum and that this biological explanation plays an important role in the syphilis epidemic. We performed a literature search and developed a mathematical model of HIV-1 and T. pallidum confection in a population with two risk groups with assortative mixing to explore the consequence on syphilis prevalence of HAART-induced changes in behaviour versus HAART-induced biological effects. Since rising syphilis incidence appears to have outpaced gonorrhoea and chlamydia, predominantly affecting HIV-1 positive MSM, behavioural factors alone may be insufficient to explain the unique, sharp increase in syphilis incidence. HAART agents have the potential to alter the innate and acquired immune responses in ways that may enhance susceptibility to T. pallidum . This raises the possibility that therapeutic and preventative HAART may inadvertently increase the incidence of syphilis, a situation that would have significant and global public health implications. We propose that additional studies investigating the interplay between HAART and enhanced T. pallidum susceptibility are needed. If our hypothesis is correct, HAART should be combined with

  6. Association between community socioeconomic factors, animal feeding operations, and campylobacteriosis incidence rates: Foodborne Diseases Active Surveillance Network (FoodNet), 2004-2010.

    Science.gov (United States)

    Rosenberg Goldstein, Rachel E; Cruz-Cano, Raul; Jiang, Chengsheng; Palmer, Amanda; Blythe, David; Ryan, Patricia; Hogan, Brenna; White, Benjamin; Dunn, John R; Libby, Tanya; Tobin-D'Angelo, Melissa; Huang, Jennifer Y; McGuire, Suzanne; Scherzinger, Karen; Lee, Mei-Ling Ting; Sapkota, Amy R

    2016-07-22

    Campylobacter is a leading cause of foodborne illness in the United States. Campylobacter infections have been associated with individual risk factors, such as the consumption of poultry and raw milk. Recently, a Maryland-based study identified community socioeconomic and environmental factors that are also associated with campylobacteriosis rates. However, no previous studies have evaluated the association between community risk factors and campylobacteriosis rates across multiple U.S. states. We obtained Campylobacter case data (2004-2010; n = 40,768) from the Foodborne Diseases Active Surveillance Network (FoodNet) and socioeconomic and environmental data from the 2010 Census of Population and Housing, the 2011 American Community Survey, and the 2007 U.S. Census of Agriculture. We linked data by zip code and derived incidence rate ratios using negative binomial regression models. Community socioeconomic and environmental factors were associated with both lower and higher campylobacteriosis rates. Zip codes with higher percentages of African Americans had lower rates of campylobacteriosis (incidence rate ratio [IRR]) = 0.972; 95 % confidence interval (CI) = 0.970,0.974). In Georgia, Maryland, and Tennessee, three leading broiler chicken producing states, zip codes with broiler operations had incidence rates that were 22 % (IRR = 1.22; 95 % CI = 1.03,1.43), 16 % (IRR = 1.16; 95 % CI = 0.99,1.37), and 35 % (IRR = 1.35; 95 % CI = 1.18,1.53) higher, respectively, than those of zip codes without broiler operations. In Minnesota and New York FoodNet counties, two top dairy producing areas, zip codes with dairy operations had significantly higher campylobacteriosis incidence rates (IRR = 1.37; 95 % CI = 1.22, 1.55; IRR = 1.19; 95 % CI = 1.04,1.36). Community socioeconomic and environmental factors are important to consider when evaluating the relationship between possible risk factors and Campylobacter infection.

  7. High Incidence of Tuberculosis Infection in Rheumatic Diseases and Impact for Chemoprophylactic Prevention of Tuberculosis Activation during Biologics Therapy

    Science.gov (United States)

    Bai, Fengmin; Zhang, Shu; Jiang, Ting; Shen, Jie; Zhu, Qi; Yue, Tao; Shao, Lingyun; Gao, Yan; Feng, Yun; Weng, Xinhua; Zou, Hejian; Zhang, Ying

    2013-01-01

    We conducted a long-term follow-up study in patients with rheumatic diseases who were candidates for biologics treatment to evaluate the effects of biologic agents on the risk of tuberculosis infection and the effect of prophylactic treatment on tuberculosis activation. One hundred one patients with rheumatic diseases who were candidates for biologics treatment were recruited, and 57 healthy subjects were recruited as controls. Tuberculin skin test (TST) and the T-SPOT.TB test were performed for all subjects at baseline. Follow-up testing by the T-SPOT.TB assay was performed every 6 months in patients with rheumatic diseases and at 2 years of recruitment in the healthy controls. In patients with rheumatic diseases and healthy controls, the TST-positive (induration, ≥10 mm) rates were 37.6% (38/101) and 34.0% (18/53), respectively (P > 0.05), while the T-SPOT.TB-positive rates were 46.5% (47/101) and 21.1 (12/57), respectively (P = 0.0019). Fifty-two patients were followed up at month 6 with a T-SPOT.TB-positive rate of 40.4%, and 49 were followed up for ≥12 months with a T-SPOT.TB-positive rate of 36.7%, with no significant difference in the positive rate at different time points including baseline (P > 0.05). Long-term follow-up revealed that conversion to T-SPOT.TB positivity occurred only in the biologics treatment group, with a positive conversion rate of 11.2% (4/38). Most importantly, no latent tuberculosis developed into active tuberculosis during follow-up with T-SPOT.TB screening and preemptive treatment with isoniazid. Biologics treatment appears to increase the risk of tuberculosis infection. However, tuberculosis activation could be prevented by preemptive isoniazid treatment in patients with latent tuberculosis infection while receiving biologics therapy. PMID:23554465

  8. Cancer mortality and incidence survey around the Aube's low- and medium-activity radioactive waste storage site

    International Nuclear Information System (INIS)

    2010-01-01

    This report presents the main results of a survey performed in 2010 to describe the health status of the population around the Aube's low- and medium-activity radioactive waste storage site. The aim of this survey was to determine whether the frequencies of death and hospitalization on account of cancer are different for this population (15 km around the site) with respect to two reference populations (the population of the Champagne-Ardennes region and the French metropolitan population). Results of mortality, hospitalization, and lung cancer are presented under the form of maps and tables giving global data or data for males, females, adults, or children

  9. Superradiance Transition and Nonphotochemical Quenching in Photosynthetic Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Berman, Gennady Petrovich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nesterov, Alexander [Universidad de Guadalajara, Departamento de Fısica, Jalisco (Mexico); Lopez, Gustavo [Universidad de Guadalajara, Departamento de Fısica, Jalisco (Mexico); Sayre, Richard Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-04-23

    Photosynthetic organisms have evolved protective strategies to allow them to survive in cases of intense sunlight fluctuation with the development of nonphotochemical quenching (NPQ). This process allows light harvesting complexes to transfer the excess sunlight energy to non-damaging quenching channels. This report compares the NPQ process with the superradiance transition (ST). We demonstrated that the maximum of the NPQ efficiency is caused by the ST to the sink associated with the CTS. However, experimental verifications are required in order to determine whether or not the NPQ regime is associated with the ST transition for real photosynthetic complexes. Indeed, it can happen that, in the photosynthetic apparatus, the NPQ regime occurs in the “non-optimal” region of parameters, and it could be independent of the ST.

  10. Cyanobacteria as photosynthetic biocatalysts: a systems biology perspective.

    Science.gov (United States)

    Gudmundsson, Steinn; Nogales, Juan

    2015-01-01

    The increasing need to replace oil-based products and to address global climate change concerns has triggered considerable interest in photosynthetic microorganisms. Cyanobacteria, in particular, have great potential as biocatalysts for fuels and fine-chemicals. During the last few years the biotechnological applications of cyanobacteria have experienced an unprecedented increase and the use of these photosynthetic organisms for chemical production is becoming a tangible reality. However, the field is still immature and many concerns about the economic feasibility of the biotechnological potential of cyanobacteria remain. In this review we describe recent successes in biofuel and fine-chemical production using cyanobacteria. We discuss the role of the photosynthetic metabolism and highlight the need for systems-level metabolic optimization in order to achieve the true potential of cyanobacterial biocatalysts.

  11. Biological optimization systems for enhancing photosynthetic efficiency and methods of use

    Science.gov (United States)

    Hunt, Ryan W.; Chinnasamy, Senthil; Das, Keshav C.; de Mattos, Erico Rolim

    2012-11-06

    Biological optimization systems for enhancing photosynthetic efficiency and methods of use. Specifically, methods for enhancing photosynthetic efficiency including applying pulsed light to a photosynthetic organism, using a chlorophyll fluorescence feedback control system to determine one or more photosynthetic efficiency parameters, and adjusting one or more of the photosynthetic efficiency parameters to drive the photosynthesis by the delivery of an amount of light to optimize light absorption of the photosynthetic organism while providing enough dark time between light pulses to prevent oversaturation of the chlorophyll reaction centers are disclosed.

  12. Enhanced Practical Photosynthetic CO2 Mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Gregory Kremer; David J. Bayless; Morgan Vis; Michael Prudich; Keith Cooksey; Jeff Muhs

    2003-07-22

    This quarterly report documents significant achievements in the Enhanced Practical Photosynthetic CO{sub 2} Mitigation project during the period from 4/2/2003 through 7/01/2003. As indicated in the list of accomplishments below we have completed some long-term model scale bioreactor tests and are prepared to begin pilot scale bioreactor testing. Specific results and accomplishments for the second quarter of 2003 include: (1) Bioreactor support systems and test facilities: (a) Qualitative long-term survivability tests for S.C.1.2(2) on Omnisil have been successfully completed and results demonstrate a growth rate that appears to be acceptable. (b) Quantitative tests of long-term growth productivity for S.C.1.2(2) on Omnisil have been completed and initial results are promising. Initial results show that the mass of organisms doubled (from 54.9 grams to 109.8 grams) in about 5 weeks. Full results will be available as soon as all membranes and filters are completely dried. The growth rate should increase significantly with the initiation of weekly harvesting during the long term tests. (c) The phase 1 construction of the pilot scale bioreactor has been completed, including the solar collector and light distribution system. We are now in the phase of system improvement as we wait for CRF-2 results in order to be able to finalize the design and construction of the pilot scale system. (d) A mass transfer experimental setup was constructed in order to measure the mass transfer rate from the gas to the liquid film flowing over a membrane and to study the hydrodynamics of the liquid film flowing over a membrane in the bioreactor. Results were reported for mass transfer coefficient, film thickness, and fluid velocity over an Omnisil membrane with a ''drilled hole'' header pipe design. (2) Organisms and Growth Surfaces: (a) A selectivity approach was used to obtain a cyanobacterial culture with elevated resistance to acid pH. Microlonies of ''3

  13. Evidence of circadian rhythms in non-photosynthetic bacteria?

    Directory of Open Access Journals (Sweden)

    Soriano María I

    2010-09-01

    Full Text Available Abstract Examples of circadian rhythms have been described in eukaryotic organisms and in photosynthetic bacteria, but direct proof of their existence in other prokaryotes is limited and has been largely ignored. The aim of this article is to review existing evidence and to present preliminary results that suggest that the heterotrophic bacterium Pseudomonas putida shows regular variations in its growth pattern synchronized with light/darkness cycles. We put forward the hypothesis that circadian regulation of certain processes can take place in non-photosynthetic prokaryotes and may represent an adaptative advantage in specific environments.

  14. Mechanisms by which the infection of Sclerotinia sclerotiorum (Lib.) de Bary affects the photosynthetic performance in tobacco leaves.

    Science.gov (United States)

    Yang, Cheng; Zhang, Zishan; Gao, Huiyuan; Liu, Meijun; Fan, Xingli

    2014-09-23

    Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic fungal pathogen which causes disease in a wide range of plants. An observed decrease in photosynthetic performance is the primary reason for the reduction of crop yield induced by S. sclerotiorum. The H2C2O4 is the main pathogenic material secreted by S. sclerotiorum, but the effects of H2C2O4 acidity and the C2O4 2- ion on photosynthetic performance remain unknown. S. sclerotiorum infection significantly decreased photosynthetic O2 evolution and the maximum quantum yield of photosystem II (Fv/Fm) in tobacco leaves under high-light. H2C2O4 (the main pathogenic material secreted by S. sclerotiorum) with pH 4.0 also significantly decreased photosynthetic performance. However, treatment with H3PO4 and HCl at the same pH as H2C2O4 caused much less decrease in photosynthetic performance than H2C2O4 did. These results verify that the acidity of the H2C2O4 secreted by S. sclerotiorum was only partially responsible for the observed decreases in photosynthesis. Treatment with 40 mM K2C2O4 decreased Fv/Fm by about 70% of the levels observed under 40 mM H2C2O4, which further demonstrates that C2O4(2-) was the primary factor that impaired photosynthetic performance during S. sclerotiorum infection. K2C2O4 treatment did not further decrease photosynthetic performance when D1 protein synthesis was fully inhibited, indicating that C2O4(2-) inhibited PSII by repressing D1 protein synthesis. It was observed that K2C2O4 treatment inhibited the rate of RuBP regeneration and carboxylation efficiency. In the presence of a carbon assimilation inhibitor, K2C2O4 2 treatment did not further decrease photosynthetic performance, which infers that C2O4(2-) inhibited PSII activity partly by repressing the carbon assimilation. In addition, it was showed that C2O4(2-) treatment inhibited the PSII activity but not the PSI activity. This study demonstrated that the damage to the photosynthetic apparatus induced by S. sclerotiorum is not

  15. Detecting and monitoring water stress states in maize crops using spectral ratios obtained in the photosynthetic domain

    Science.gov (United States)

    Baranoski, Gladimir V. G.; Van Leeuwen, Spencer R.

    2017-07-01

    The reliable detection and monitoring of changes in the water status of crops composed of plants like maize, a highly adaptable C4 species in large demand for both food and biofuel production, are longstanding remote sensing goals. Existing procedures employed to achieve these goals rely predominantly on the spectral signatures of plant leaves in the infrared domain where the light absorption within the foliar tissues is dominated by water. It has been suggested that such procedures could be implemented using subsurface reflectance to transmittance ratios obtained in the visible (photosynthetic) domain with the assistance of polarization devices. However, the experiments leading to this proposition were performed on detached maize leaves, which were not influenced by the whole (living) plant's adaptation mechanisms to water stress. In this work, we employ predictive simulations of light-leaf interactions in the photosynthetic domain to demonstrate that the living specimens' physiological responses to dehydration stress should be taken into account in this context. Our findings also indicate that a reflectance to transmittance ratio obtained in the photosynthetic domain at a lower angle of incidence without the use of polarization devices may represent a cost-effective alternative for the assessment of water stress states in maize crops.

  16. An Excel tool for deriving key photosynthetic parameters from combined gas exchange and chlorophyll fluorescence: theory and practice.

    Science.gov (United States)

    Bellasio, Chandra; Beerling, David J; Griffiths, Howard

    2016-06-01

    Combined photosynthetic gas exchange and modulated fluorometres are widely used to evaluate physiological characteristics associated with phenotypic and genotypic variation, whether in response to genetic manipulation or resource limitation in natural vegetation or crops. After describing relatively simple experimental procedures, we present the theoretical background to the derivation of photosynthetic parameters, and provide a freely available Excel-based fitting tool (EFT) that will be of use to specialists and non-specialists alike. We use data acquired in concurrent variable fluorescence-gas exchange experiments, where A/Ci and light-response curves have been measured under ambient and low oxygen. From these data, the EFT derives light respiration, initial PSII (photosystem II) photochemical yield, initial quantum yield for CO2 fixation, fraction of incident light harvested by PSII, initial quantum yield for electron transport, electron transport rate, rate of photorespiration, stomatal limitation, Rubisco (ribulose 1·5-bisphosphate carboxylase/oxygenase) rate of carboxylation and oxygenation, Rubisco specificity factor, mesophyll conductance to CO2 diffusion, light and CO2 compensation point, Rubisco apparent Michaelis-Menten constant, and Rubisco CO2 -saturated carboxylation rate. As an example, a complete analysis of gas exchange data on tobacco plants is provided. We also discuss potential measurement problems and pitfalls, and suggest how such empirical data could subsequently be used to parameterize predictive photosynthetic models. © 2015 John Wiley & Sons Ltd.

  17. Sustained photosynthetic performance of Coffea spp. under long-term enhanced [CO2].

    Directory of Open Access Journals (Sweden)

    José C Ramalho

    Full Text Available Coffee is one of the world's most traded agricultural products. Modeling studies have predicted that climate change will have a strong impact on the suitability of current cultivation areas, but these studies have not anticipated possible mitigating effects of the elevated atmospheric [CO2] because no information exists for the coffee plant. Potted plants from two genotypes of Coffea arabica and one of C. canephora were grown under controlled conditions of irradiance (800 μmol m(-2 s(-1, RH (75% and 380 or 700 μL CO2 L(-1 for 1 year, without water, nutrient or root development restrictions. In all genotypes, the high [CO2] treatment promoted opposite trends for stomatal density and size, which decreased and increased, respectively. Regardless of the genotype or the growth [CO2], the net rate of CO2 assimilation increased (34-49% when measured at 700 than at 380 μL CO2 L(-1. This result, together with the almost unchanged stomatal conductance, led to an instantaneous water use efficiency increase. The results also showed a reinforcement of photosynthetic (and respiratory components, namely thylakoid electron transport and the activities of RuBisCo, ribulose 5-phosphate kinase, malate dehydrogenase and pyruvate kinase, what may have contributed to the enhancements in the maximum rates of electron transport, carboxylation and photosynthetic capacity under elevated [CO2], although these responses were genotype dependent. The photosystem II efficiency, energy driven to photochemical events, non-structural carbohydrates, photosynthetic pigment and membrane permeability did not respond to [CO2] supply. Some alterations in total fatty acid content and the unsaturation level of the chloroplast membranes were noted but, apparently, did not affect photosynthetic functioning. Despite some differences among the genotypes, no clear species-dependent responses to elevated [CO2] were observed. Overall, as no apparent sign of photosynthetic down

  18. Sustained Photosynthetic Performance of Coffea spp. under Long-Term Enhanced [CO2

    Science.gov (United States)

    Ramalho, José C.; Rodrigues, Ana P.; Semedo, José N.; Pais, Isabel P.; Martins, Lima D.; Simões-Costa, Maria C.; Leitão, António E.; Fortunato, Ana S.; Batista-Santos, Paula; Palos, Isabel M.; Tomaz, Marcelo A.; Scotti-Campos, Paula; Lidon, Fernando C.; DaMatta, Fábio M.

    2013-01-01

    Coffee is one of the world’s most traded agricultural products. Modeling studies have predicted that climate change will have a strong impact on the suitability of current cultivation areas, but these studies have not anticipated possible mitigating effects of the elevated atmospheric [CO2] because no information exists for the coffee plant. Potted plants from two genotypes of Coffea arabica and one of C. canephora were grown under controlled conditions of irradiance (800 μmol m-2 s-1), RH (75%) and 380 or 700 μL CO2 L-1 for 1 year, without water, nutrient or root development restrictions. In all genotypes, the high [CO2] treatment promoted opposite trends for stomatal density and size, which decreased and increased, respectively. Regardless of the genotype or the growth [CO2], the net rate of CO2 assimilation increased (34-49%) when measured at 700 than at 380 μL CO2 L-1. This result, together with the almost unchanged stomatal conductance, led to an instantaneous water use efficiency increase. The results also showed a reinforcement of photosynthetic (and respiratory) components, namely thylakoid electron transport and the activities of RuBisCo, ribulose 5-phosphate kinase, malate dehydrogenase and pyruvate kinase, what may have contributed to the enhancements in the maximum rates of electron transport, carboxylation and photosynthetic capacity under elevated [CO2], although these responses were genotype dependent. The photosystem II efficiency, energy driven to photochemical events, non-structural carbohydrates, photosynthetic pigment and membrane permeability did not respond to [CO2] supply. Some alterations in total fatty acid content and the unsaturation level of the chloroplast membranes were noted but, apparently, did not affect photosynthetic functioning. Despite some differences among the genotypes, no clear species-dependent responses to elevated [CO2] were observed. Overall, as no apparent sign of photosynthetic down-regulation was found, our data

  19. SOUR CHERRY (Prunus cerasus L. GENETIC VARIABILITY AND PHOTOSYNTHETIC EFFICIENCY DURING DROUGHT

    Directory of Open Access Journals (Sweden)

    Marija Viljevac

    2012-12-01

    Full Text Available Sour cherry is an important fruit in Croatian orchards. Cultivar Oblačinska is predominant in existing orchards with noted intracultivar phenotypic heterogeneity. In this study, the genetic variability of 22 genotypes of cvs. Oblačinska, Maraska and Cigančica, as well as standard cvs. Kelleris 14, Kelleris 16, Kereška, Rexelle and Heimann conserved were investigated. Two types of molecular markers were used: microsatellite markers (SSR in order to identify intercultivar, and AFLP in order to identify intracultivar variabilities. A set of 12 SSR markers revealed small genetic distance between cvs. Maraska and Oblačinska while cv. Cigančica is affined to cv. Oblačinska. Furthermore, cvs. Oblačinska, Cigančica and Maraska were characterized compared to standard ones. AFLP markers didn`t confirm significant intracultivar variability of cv. Oblačinska although the variability has been approved at the morphological, chemical and pomological level. Significant corelation between SSR and AFLP markers was found. Identification of sour cherry cultivars tolerant to drought will enable the sustainability of fruit production with respect to the climate change in the future. For this purpose, the tolerance of seven sour cherry genotypes (cvs. Kelleris 16, Maraska, Cigančica and Oblačinska represented by 4 genotypes: OS, 18, D6 and BOR to drought conditions was tested in order to isolate genotypes with the desired properties. In the greenhouse experiment, cherry plants were exposed to drought stress. The leaf relative water content, OJIP test parameters which specify efficiency of the photosynthetic system based on measurements of chlorophyll a fluorescence, and concentrations of photo-synthetic pigments during the experiment were measured as markers of drought tolerance. Photosynthetic performance index (PIABS comprises three key events in the reaction centre of photosystem II affecting the photosynthetic activity: the absorption of energy

  20. Thermodynamic efficiency of synthesis, storage and breakdown of the high-energy metabolites by photosynthetic microalgae

    International Nuclear Information System (INIS)

    Sorgüven, Esra; Özilgen, Mustafa

    2013-01-01

    Lipids and carbohydrates are employed in the nature to store internal energy due to the large number of the high energy atomic bonds in their structure. Internal energy stored in the bonds is used to fuel work producing engines or metabolic activity of living organisms. This paper investigates the thermodynamic efficiency of the glucose and lipid synthesis and breakdown by photosynthetic microalgae. Photosynthetic microalgae are able to convert 3.8% of the solar exergy into the chemical exergy of algal lipid. As the microalgae convert the first product of the photosynthesis, i.e. glucose, into lipid, 47–49% of the chemical exergy is lost. If the microalgal cell consumes the photosynthetically produced glucose for its own energy demand, then about 30% of the glucose exergy can be converted into work potential in case of immediate and short-term energy demands. Organism can convert about 22% of the glucose exergy into work potential after a long-term storage. If the algal lipid is harvested for biodiesel production and the produced biodiesel is combusted in a Diesel engine, then about 17% of the exergy of the photosynthetically produced glucose can be converted into useful work. Biodiesel is among the most popular renewable fuels. The lipids are harvested from their storage in the cells to produce biodiesel before following the lipid breakdown path of the cellular metabolism. Our analysis indicates that, extracting the first product of photosynthesis, i.e. glucose or glucose polymers instead of lipids may be more efficient thermodynamically, if new motors capable to extract their bond energy is developed. - Highlights: • Photosynthetic microalgae convert 3.8% of the solar exergy into the chemical exergy of algal lipid. • Converting the first product of the photosynthesis (glucose) into lipid causes 47–49% of exergy loss. • Organism can convert 30% of the glucose exergy into work potential for its own immediate or short-term energy demand. • Organism can

  1. Reduction of photosynthetically active radiation under extreme stratospheric aerosol loads

    Energy Technology Data Exchange (ETDEWEB)

    Gerstl, S.A.W.; Zardecki, A.

    1981-08-01

    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 artificially increased aerosol amounts until the postulated darkness scenario is obtained. Thus we find that a total stratospheric aerosol mass between 1 and 4 times 10/sup 1/ g is sufficient to reduce photosynthesis to 10/sup -3/ of normal. We also infer from this result tha the impact of a 0.4- to 3-km-diameter asteroid or a close encounter with a Halley-size comet may deposit that amount of particulates into the stratosphere. The darkness scenario of Alvarez et al. is thus shown to be a possible extinction mechanism, even with smaller size asteroids of comets than previously estimated.

  2. Reduction of photosynthetically active radiation under extreme stratospheric aerosol loads

    International Nuclear Information System (INIS)

    Gerstl, S.A.W.; Zardecki, A.

    1981-08-01

    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 artificially increased aerosol amounts until the postulated darkness scenario is obtained. Thus we find that a total stratospheric aerosol mass between 1 and 4 times 10 1 g is sufficient to reduce photosynthesis to 10 -3 of normal. We also infer from this result tha the impact of a 0.4- to 3-km-diameter asteroid or a close encounter with a Halley-size comet may deposit that amount of particulates into the stratosphere. The darkness scenario of Alvarez et al. is thus shown to be a possible extinction mechanism, even with smaller size asteroids of comets than previously estimated

  3. The effect of nitrogen on the development and photosynthetic activity ...

    African Journals Online (AJOL)

    The form and concentration of nitrogen applied influenced morphological development and flowering, a result that could have important economic implications. Keywords: ammonium nitrogen; botany; digitaria eriantha; Digitaria eriantha subspecies eriantha; dry matter production; leaf area; morphological development; net ...

  4. Effect of Nitrogen Nutritional Stress on some Mineral Nutrients and Photosynthetic Apparatus of Zea mays L. and Vigna unguiculata L.

    Directory of Open Access Journals (Sweden)

    Akinbode Foluso OLOGUNDUDU

    2013-08-01

    Full Text Available The study investigated the responses of maize (Zea mays L. and cowpea (Vigna unguiculata L. Walp. seedlings metabolic activities and photosynthetic apparatus to nitrogen nutritional stress. Germination of seeds was done using treated sand in sixty plastic pots and the seedlings were divided into four nutrient regimes. A group of the seedlings was nutrient stressed by administering 200 ml of complete nutrient solution minus nitrogen (-N while the other groups were fed with five times (X5N and ten times (X10N the optimal concentration of nitrogen and the last regime was fed with full nutrient solution (FN. The photosynthetic parameters studied included chlorophylls ‘a’ and ‘b’ respectively; carotenes and xanthophyll while the mineral elements investigated include potassium, calcium and magnesium. The result of the growth analysis showed that nitrogen deficiency promotes an increase in the content of abscisic acid (ABA, causing stomatal closure and a reduction in photosynthesis. This explains the higher rate of leaf abscission in -N plants. A comparison of calcium ion and magnesium ion concentrations in both optimal and stressed conditions reveals that the two ions show antagonism in uptake. There is a correlation between nitrogen and magnesium accumulation as magnesium ion plays a vital role in chlorophyll biosynthesis, protein synthesis and photosynthesis. The pattern of accumulation of photosynthetic apparatus in both maize and cowpea follow a similar pattern. Chlorophyll a dictated the growth pattern of other photosynthetic apparatus in both Zea mays and Vigna unguiculata.

  5. Nonlinear spectral mixture effects for photosynthetic/non-photosynthetic vegetation cover estimates of typical desert vegetation in western China.

    Directory of Open Access Journals (Sweden)

    Cuicui Ji

    Full Text Available Desert vegetation plays significant roles in securing the ecological integrity of oasis ecosystems in western China. Timely monitoring of photosynthetic/non-photosynthetic desert vegetation cover is necessary to guide management practices on land desertification and research into the mechanisms driving vegetation recession. In this study, nonlinear spectral mixture effects for photosynthetic/non-photosynthetic vegetation cover estimates are investigated through comparing the performance of linear and nonlinear spectral mixture models with different endmembers applied to field spectral measurements of two types of typical desert vegetation, namely, Nitraria shrubs and Haloxylon. The main results were as follows. (1 The correct selection of endmembers is important for improving the accuracy of vegetation cover estimates, and in particular, shadow endmembers cannot be neglected. (2 For both the Nitraria shrubs and Haloxylon, the Kernel-based Nonlinear Spectral Mixture Model (KNSMM with nonlinear parameters was the best unmixing model. In consideration of the computational complexity and accuracy requirements, the Linear Spectral Mixture Model (LSMM could be adopted for Nitraria shrubs plots, but this will result in significant errors for the Haloxylon plots since the nonlinear spectral mixture effects were more obvious for this vegetation type. (3 The vegetation canopy structure (planophile or erectophile determines the strength of the nonlinear spectral mixture effects. Therefore, no matter for Nitraria shrubs or Haloxylon, the non-linear spectral mixing effects between the photosynthetic / non-photosynthetic vegetation and the bare soil do exist, and its strength is dependent on the three-dimensional structure of the vegetation canopy. The choice of linear or nonlinear spectral mixture models is up to the consideration of computational complexity and the accuracy requirement.

  6. Photoprotection Conferred by Changes in Photosynthetic Protein Levels and Organization during Dehydration of a Homoiochlorophyllous Resurrection Plant1

    Science.gov (United States)

    Charuvi, Dana; Nevo, Reinat; Shimoni, Eyal; Naveh, Leah; Zia, Ahmad; Adam, Zach; Farrant, Jill M.; Kirchhoff, Helmut; Reich, Ziv

    2015-01-01

    During desiccation, homoiochlorophyllous resurrection plants retain most of their photosynthetic apparatus, allowing them to resume photosynthetic activity quickly upon water availability. These plants rely on various mechanisms to prevent the formation of reactive oxygen species and/or protect their tissues from the damage they inflict. In this work, we addressed the issue of how homoiochlorophyllous resurrection plants deal with the problem of excessive excitation/electron pressures during dehydration using Craterostigma pumilum as a model plant. To investigate the alterations in the supramolecular organization of photosynthetic protein complexes, we examined cryoimmobilized, freeze-fractured leaf tissues using (cryo)scanning electron microscopy. These examinations revealed rearrangements of photosystem II (PSII) complexes, including a lowered density during moderate dehydration, consistent with a lower level of PSII proteins, as shown by biochemical analyses. The latter also showed a considerable decrease in the level of cytochrome f early during dehydration, suggesting that initial regulation of the inhibition of electron transport is achieved via the cytochrome b6f complex. Upon further dehydration, PSII complexes are observed to arrange into rows and semicrystalline arrays, which correlates with the significant accumulation of sucrose and the appearance of inverted hexagonal lipid phases within the membranes. As opposed to PSII and cytochrome f, the light-harvesting antenna complexes of PSII remain stable throughout the course of dehydration. Altogether, these results, along with photosynthetic activity measurements, suggest that the protection of retained photosynthetic components is achieved, at least in part, via the structural rearrangements of PSII and (likely) light-harvesting antenna complexes into a photochemically quenched state. PMID:25713340

  7. On the photosynthetic and devlopmental responses of leaves to the spectral composition of light

    NARCIS (Netherlands)

    Hogewoning, S.W.

    2010-01-01

    Key words: action spectrum, artificial solar spectrum, blue light, Cucumis sativus, gas-exchange, light-emitting diodes (LEDs), light interception, light quality, non-photosynthetic pigments, photo-synthetic capacity, photomorphogenesis, photosystem excitation balance, quantum yield, red light.

  8. On the photosynthetic and devlopmental responses of leaves to the spectral composition of light

    NARCIS (Netherlands)

    Hogewoning, S.W.

    2010-01-01

    Key words: action spectrum, artificial solar spectrum, blue light, Cucumis sativus, gas-exchange, light-emitting diodes (LEDs), light interception, light quality, non-photosynthetic pigments, photo-synthetic capacity, photomorphogenesis, photosystem excitation balance, quantum yield, red light. A

  9. Enhanced Practical Photosynthetic CO2 Mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Gregory Kremer; David J. Bayless; Morgan Vis; Michael Prudich; Keith Cooksey; Jeff Muhs

    2006-01-15

    This final report highlights significant achievements in the Enhanced Practical Photosynthetic CO{sub 2} Mitigation Project during the period from 10/1/2001 through 01/02/2006. As indicated in the list of accomplishments below, our efforts during this project were focused on the selection of candidate organisms and growth surfaces and initiating long-term tests in the bench-scale and pilot-scale bioreactor test systems. Specific results and accomplishments for the program include: (1) CRF-2 test system: (a) Sampling test results have shown that the initial mass of algae loaded into the Carbon Recycling Facility Version 2 (CRF-2) system can be estimated with about 3% uncertainty using a statistical sampling procedure. (b) The pressure shim header pipe insert design was shown to have better flow for harvesting than the drilled-hole design. (c) The CRF-2 test system has undergone major improvements to produce the high flow rates needed for harvesting (as determined by previous experiments). The main changes to the system are new stainless steel header/frame units, with increased flow capacity and a modified pipe-end-sealing method to improve flow uniformity, and installation and plumbing for a new high flow harvesting pump. Qualitative system tests showed that the harvesting system performed wonderfully, cleaning the growth surfaces within a matter of seconds. (d) Qualitative tests have shown that organisms can be repopulated on a harvested section of a bioreactor screen, demonstrating that continuous bioreactor operation is feasible, with continuous cycles of harvesting and repopulating screens. (e) Final preparations are underway for quantitative, long-term tests in the CRF-2 with weekly harvesting. (2) Pilot-scale test system: (a) The construction of the pilot-scale bioreactor was completed, including the solar collector and light distribution system. Over the course of the project, the solar collector used in the light delivery system showed some degradation, but

  10. Leisure-time physical activity and incident metabolic syndrome: a systematic review and dose-response meta-analysis of cohort studies.

    Science.gov (United States)

    Zhang, Dongdong; Liu, Xuejiao; Liu, Yu; Sun, Xizhuo; Wang, Bingyuan; Ren, Yongcheng; Zhao, Yang; Zhou, Junmei; Han, Chengyi; Yin, Lei; Zhao, Jingzhi; Shi, Yuanyuan; Zhang, Ming; Hu, Dongsheng

    2017-10-01

    Leisure-time physical activity (LTPA) has been suggested to reduce risk of metabolic syndrome (MetS). However, a quantitative comprehensive assessment of the dose-response association between LTPA and incident MetS has not been reported. We performed a meta-analysis of studies assessing the risk of MetS with LTPA. MEDLINE via PubMed and EMBase databases were searched for relevant articles published up to March 13, 2017. Random-effects models were used to estimate the summary relative risk (RR) of MetS with LTPA. Restricted cubic splines were used to model the dose-response association. We identified 16 articles (18 studies including 76,699 participants and 13,871 cases of MetS). We found a negative linear association between LTPA and incident MetS, with a reduction of 8% in MetS risk per 10 metabolic equivalent of task (MET) h/week increment. According to the restricted cubic splines model, risk of MetS was reduced 10% with LTPA performed according to the basic guideline-recommended level of 150min of moderate PA (MPA) per week (10METh/week) versus inactivity (RR=0.90, 95% CI 0.86-0.94). It was reduced 20% and 53% with LTPA at twice (20METh/week) and seven times (70METh/week) the basic recommended level (RR=0.80, 95% CI 0.74-0.88 and 0.47, 95% CI 0.34-0.64, respectively). Our findings provide quantitative data suggesting that any amount of LTPA is better than none and that LTPA substantially exceeding the current LTPA guidelines is associated with an additional reduction in MetS risk. Copyright © 2017. Published by Elsevier Inc.

  11. Five-year decreased incidence of surgical site infections following gastrectomy and prosthetic joint replacement surgery through active surveillance by the Korean Nosocomial Infection Surveillance System.

    Science.gov (United States)

    Choi, H J; Adiyani, L; Sung, J; Choi, J Y; Kim, H B; Kim, Y K; Kwak, Y G; Yoo, H; Lee, Sang-Oh; Han, S H; Kim, S R; Kim, T H; Lee, H M; Chun, H K; Kim, J-S; Yoo, J D; Koo, H-S; Cho, E H; Lee, K W

    2016-08-01

    Surveillance of healthcare-associated infection has been associated with a reduction in surgical site infection (SSI). To evaluate the Korean Nosocomial Infection Surveillance System (KONIS) in order to assess its effects on SSI since it was introduced. SSI data after gastrectomy, total hip arthroplasty (THA), and total knee arthroplasty (TKA) between 2008 and 2012 were analysed. The pooled incidence of SSI was calculated for each year; the same analyses were also conducted from hospitals that had participated in KONIS for at least three consecutive years. Standardized SSI rates for each year were calculated by adjusting for SSI risk factors. SSI trends were analysed using the Cochran-Armitage test. The SSI rate following gastrectomy was 3.12% (522/16,918). There was a significant trend of decreased crude SSI rates over five years. This trend was also evident in analysis of hospitals that had participated for more than three years. The SSI rate for THA was 2.05% (157/7656), which decreased significantly from 2008 to 2012. The risk factors for SSI after THA included the National Nosocomial Infections Surveillance risk index, trauma, reoperation, and age (60-69 years). The SSI rate for TKA was 1.90% (152/7648), which also decreased significantly during a period of five years. However, the risk-adjusted analysis of SSI did not show a significant decrease for all surgical procedures. The SSI incidence of gastrectomy and prosthetic joint replacement declined over five years as a result of active surveillance by KONIS. Copyright © 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  12. Skin cancer in the military: a systematic review of melanoma and non-melanoma skin cancer incidence, prevention, and screening among active duty and veteran personnel.

    Science.gov (United States)

    Riemenschneider, Kelsie; Liu, Jesse; Powers, Jennifer G

    2017-12-29

    Occupational sun exposure is a well-studied risk factor for skin cancer development, but more work is needed to assess melanoma and non-melanoma skin cancer risk among U.S. military personnel to improve education and screening efforts in this population. To conduct an extensive review of skin cancer risks for U.S. military personnel to inform preventative education, diagnosis, and treatment efforts to better protect these individuals from future skin cancer development. A systematic review of published studies on the subject of melanoma and non-melanoma skin cancer in military personnel was conducted. Nine studies describing skin cancer incidence in the United States military were identified, with four studies specific to melanoma. The study findings reveal an increased risk of melanoma associated with service in the military or prisoner of war status. Service in tropical environments was associated with an increased incidence of both melanoma and non-melanoma skin cancer among World War II soldiers. Two studies found that increased melanoma risk was also branch-dependent, with the highest rates among the United States Air Force (USAF) branch. Several of the reviewed studies implicated increased sun exposure during military service and lack of sufficient sun protection as the causes of higher rates of skin cancer among U.S. military and veteran populations as compared to the non-military population in the US. The reviewed articles have variable results; a prospective randomized controlled trial would be helpful to develop interventions that mitigate skin cancer risk in the U.S. military. This review identifies an abundance of evidence for an increased risk of skin cancer development among U.S. active duty and veteran populations. Copyright © 2017. Published by Elsevier Inc.

  13. Molecular Regulation of Photosynthetic Carbon Dioxide Fixation in Nonsulfur Purple Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tabita, Fred Robert [The Ohio State Univ., Columbus, OH (United States)

    2015-12-01

    The overall objective of this project is to determine the mechanism by which a transcriptional activator protein affects CO2 fixation (cbb) gene expression in nonsulfur purple photosynthetic bacteria, with special emphasis to Rhodobacter sphaeroides and with comparison to Rhodopseudomonas palustris. These studies culminated in several publications which indicated that additional regulators interact with the master regulator CbbR in both R. sphaeroides and R. palustris. In addition, the interactive control of the carbon and nitrogen assimilatory pathways was studied and unique regulatory signals were discovered.

  14. Light-driven oxidation of polysaccharides by photosynthetic pigments and a metalloenzyme

    DEFF Research Database (Denmark)

    Cannella, David; Möllers, K. Benedikt; Frigaard, Niels-Ulrik

    2016-01-01

    the effect of using excited photosynthetic pigments as electron donors. LPMOs combined with pigments and reducing agents were exposed to light, which resulted in a never before seen 100-fold increase in catalytic activity. In addition, LPMO substrate specificity was broadened to include both cellulose...... and hemicellulose. LPMO enzymes and pigment derivatives common in the environment of plant-degrading organisms thus form a highly reactive and stable light-driven system increasing the turnover rate and versatility of LPMOs. This light-driven system may find applications in biotechnology and chemical processing....

  15. The role of energy losses in photosynthetic light harvesting

    NARCIS (Netherlands)

    Kruger, T. P. J.; van Grondelle, R.

    2017-01-01

    Photosynthesis operates at the bottom of the food chain to convert the energy of light into carbohydrates at a remarkable global rate of about 130 TW. Nonetheless, the overall photosynthetic process has a conversion efficiency of a few percent at best, significantly less than bottom-up photovoltaic

  16. Photosynthetic behaviour of Arabidopsis thaliana (Pa-1 accession ...

    African Journals Online (AJOL)

    The growth reduction observed in many plants caused by salinity is often associated with a decrease in their photosynthetic capacity. This effect could be associated with the partial stomatal closure and/or the non-stomatal limitation which involves the decrease in ribulose-1,5-bisphosphate carboxylase oxygenase ...

  17. Continuous Cultivation of Photosynthetic Bacteria for Fatty Acids Production

    DEFF Research Database (Denmark)

    Kim, Dong-Hoon; Lee, Ji-Hye; Hwang, Yuhoon

    2013-01-01

    In the present work, we introduced a novel approach for microbial fatty acids (FA) production. Photosynthetic bacteria, Rhodobacter sphaeroides KD131, were cultivated in a continuous-flow, stirred-tank reactor (CFSTR) at various substrate (lactate) concentrations.At hydraulic retention time (HRT)....... sphaeroides was around 35% of dry cell weight, mainly composed of vaccenic acid (C18:1, omega-7)....

  18. Photosynthetic responses of pea plants ( Pisum sativum L. cv. Little ...

    African Journals Online (AJOL)

    season in three pots arranged at four localities in Riyadh city, KSA. Photosynthetic rates (Pn) were measured three times during vegetative and reproductive stages with portable gas exchange system (LI-COR 6400). In general, Pn rates were highly ...

  19. Heat shock response in photosynthetic organisms: membrane and lipid connections.

    NARCIS (Netherlands)

    Horvath, I.; Glatz, A.; Nakamoto, H.; Mishkind, M.L.; Munnik, T.; Saidi, Y.; Goloubinoff, P.; Harwood, J.L.; Vigh, L.

    2012-01-01

    The ability of photosynthetic organisms to adapt to increases in environmental temperatures is becoming more important with climate change. Heat stress is known to induce heat-shock proteins (HSPs) many of which act as chaperones. Traditionally, it has been thought that protein denaturation acts as

  20. Effects of 1-butanol, neomycin and calcium on the photosynthetic ...

    African Journals Online (AJOL)

    ajl yemi

    Institute of Food Crops, Jiangsu High Quality Rice R&D Center, Jiangsu Academy of Agricultural Sciences, Nanjing,. Jiangsu Province, 210014, China. Accepted 31 October, 2011. The effects .... and blue light source under the open system, with the following conditions: 1200 µmol m-2s-1 photosynthetic photon flux density.

  1. An Improved Method for Extraction and Separation of Photosynthetic Pigments

    Science.gov (United States)

    Katayama, Nobuyasu; Kanaizuka, Yasuhiro; Sudarmi, Rini; Yokohama, Yasutsugu

    2003-01-01

    The method for extracting and separating hydrophobic photosynthetic pigments proposed by Katayama "et al." ("Japanese Journal of Phycology," 42, 71-77, 1994) has been improved to introduce it to student laboratories at the senior high school level. Silica gel powder was used for removing water from fresh materials prior to…

  2. The interaction of light and microwaves with photosynthetic pigments

    NARCIS (Netherlands)

    Bent, van der S.J.

    1977-01-01

    In this Thesis the results of investigations on the lowest excited triplet state of photosynthetic pigments and some model compounds are presented, partly as reprints of published papers. Most of the experiments are carried out using ODMR ( O ptically D etected

  3. Photosynthetic induction in leaves of two cucumber genotypes ...

    African Journals Online (AJOL)

    user

    2011-03-21

    Mar 21, 2011 ... 2 with low light-sensitivity were used to study the response of gas exchange, chlorophyll fluorescence ... The time of net photosynthetic rate (PN), stomatal conductance (gs), actual photosystem II efficiency ... levels (steady-state) of cucumber leaves acclimated to low-light displayed longer induction process.

  4. Abscisic acid effects on water and photosynthetic characteristics of ...

    African Journals Online (AJOL)

    The aim of this study is to compare the water and photosynthetic characteristics of two xerophilic ecotypes of Atriplex halimus (L.). Seeds collected from two different sites Djelfa and Oran are germinated in controlled greenhouse. After 6 months, the plantlets were treated 21 days with increasing concentrations of abscisic ...

  5. Changes in photosynthetic properties and antioxidative system of ...

    African Journals Online (AJOL)

    Seedlings of the Cuiguan cultivar of the Asian pear (Pyrus pyrifolia) were used to study the effects of boron toxicity on leaf photosynthetic properties and lipid peroxidation. The plants were grown hydroponically and treated with four concentrations of boron: 10 (CK), 100, 300 and 500 μmol·L-1. After 16 weeks of treatment, ...

  6. Variability of photosynthetic pigments in the Colombian Pacific ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 111; Issue 3. Variability of photosynthetic pigments in the Colombian Pacific Ocean and its relationship with the wind field using ADEOS-I data. Efrain Rodriguez-Rubio Jose Stuardo. Volume 111 Issue 3 September 2002 pp 227-236 ...

  7. Osmotic potential, photosynthetic abilities and growth characters of ...

    African Journals Online (AJOL)

    A positive correlation between physiological and growth parameters, including osmotic potential, photosynthetic pigments and water oxidation in photosystem II and Pn was demonstrated. These data provide the basis for the establishment of multivariate criteria for water deficit tolerance screening in oil palm breeding ...

  8. Photosynthetic incorporation of 14C by Stevia rebaudiana

    International Nuclear Information System (INIS)

    Ferraresi, M. de L.; Ferraresi Filho, O.; Bracht, A.

    1985-01-01

    The photosynthetic incorporation of 14 by Stevia rebaudiana specimens was investigated. The 14 C incorporation, when the isotope was furnished to the plant in form of 14 CO 2 , was rapid. After 24 hours, the radioactivity has been incorporated into a great number of compounds including pigments, terpenes, glucose, cellulose and also stevioside and its derivatives. (M.A.C.) [pt

  9. Critical responses of photosynthetic efficiency in Campsis radicans ...

    African Journals Online (AJOL)

    Critical responses of photosynthetic efficiency in Campsis radicans (L.) Seem to soil water and light intensities. ... In order to maintain the normal plant growth and have higher PN, LUE, and WUE synchronously, the range of Wr was from 49.5 to 71.1%. The optimum Wr was 71.1%, and the minimum Wr was 28.2% for the ...

  10. Determination of photosynthetic and enzymatic biomarkers sensitivity used to evaluate toxic effects of copper and fludioxonil in alga Scenedesmus obliquus

    International Nuclear Information System (INIS)

    Dewez, David; Geoffroy, Laure; Vernet, Guy; Popovic, Radovan

    2005-01-01

    Modulated PAM fluorometry and Plant Efficiency Analyser methods were used to investigate photosynthetic fluorescence parameters of alga Scenedesmus obliquus exposed to inhibitory effect of fungicides copper sulphate and fludioxonil (N-(4-nitrophenyl)-N'-propyl-uree). The change of those parameters were studied when alga S. obliquus have been exposed during 48 h to different concentrations of fungicides (1, 2 and 3 mg l -1 ). Under the same condition, enzymatic activities of catalase, ascorbate peroxidase, glutathione reductase and glutathione S-transferase were investigated to evaluate antioxidative response to fungicides effects. The change of sensitivity of those parameters was dependent to the mode of fungicide action, their concentration and time of exposure. For copper effects, the most indicative photosynthetic biomarkers were parameters Q N as non-photochemical fluorescence quenching, Q Emax as the proton induced fluorescence quenching and ABS/RC as the antenna size per photosystem II reaction center. Copper induced oxidative stress was indicated by increased activity of catalase serving as the most sensitive and valuable enzymatic biomarker. On the other hand, fludioxonil effect on photosynthetic parameters was very negligible and consequently not very useful as biomarkers. However, fludioxonil induced strong antioxidative activities associated with cytosol enzymes, as we found for catalase, ascorbate peroxidase and glutathione S-transferase activities. By obtained results, we may suggest for the activation of those enzymes to be sensitive and valuable biomarkers of oxidative stress induced by fludioxonil. Determination of biomarkers sensitivity may offer advantages in providing real criteria to use them for ecotoxicological diagnostic studies

  11. Thermoluminescence as a complementary technique for the toxicological evaluation of chemicals in photosynthetic organisms

    Energy Technology Data Exchange (ETDEWEB)

    Repetto, Guillermo, E-mail: grepkuh@upo.es [Departamento de Biología Molecular e Ingeniería Bioquímica, Área de Toxicología, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013 Seville (Spain); Zurita, Jorge L. [Departamento de Biología Molecular e Ingeniería Bioquímica, Área de Toxicología, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013 Seville (Spain); Roncel, Mercedes; Ortega, José M. [Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Seville (Spain)

    2015-01-15

    Highlights: • There are very few toxicological applications of thermoluminescence. • It is a luminescence emission induced by heating the sample in the dark. • It is useful for study the photosystem II function and the level of lipid peroxidation. - Abstract: Thermoluminescence is a simple technique very useful for studying electron transfer reactions on photosystem II (standard thermoluminescence) or the level of lipid peroxidation in membranes (high temperature thermoluminescence) in photosynthetic organisms. Both techniques were used to investigate the effects produced on Chlorella vulgaris cells by six compounds: the chemical intermediates bromobenzene and diethanolamine, the antioxidant propyl gallate, the semiconductor indium nitrate, the pesticide sodium monofluoroacetate and the antimalarial drug chloroquine. Electron transfer activity of the photosystem II significantly decreased after the exposure of Chlorella cells to all the six chemicals used. Lipid peroxidation was slightly decreased by the antioxidant propyl gallate, not changed by indium nitrate and very potently stimulated by diethanolamine, chloroquine, sodium monofluoroacetate and bromobenzene. For five of the chemicals studied (not bromobenzene) there is a very good correlation between the cytotoxic effects in Chlorella cells measured by the algal growth inhibition test, and the inhibition of photosystem II activity. The results suggest that one very important effect of these chemicals in Chlorella cells is the inhibition of photosynthetic metabolism by the blocking of photosystem II functionality. In the case of sodium monofluoroacetate, diethanolamine and chloroquine this inhibition seems to be related with the induction of high level of lipid peroxidation in cells that may alter the stability of photosystem II. The results obtained by both techniques supply information that can be used as a supplement to the growth inhibition test and allows a more complete assessment of the effects of

  12. [THE EFFECT OF ACID RAIN ON ULTRASTRUCTURE AND FUNCTIONAL PARAMETERS OF PHOTOSYNTHETIC APPARATUS OF PEA LEAVES].

    Science.gov (United States)

    Polishchuk, A V; Vodka, M V; Belyavskaya, N A; Khomochkin, A P; Zolotareva, E K

    2016-01-01

    The effects of simulated acid rain (SAR) on the ultrastructure and functional parameters of the photosynthetic apparatus were studied using 14-day-old pea leaves as test system. Pea plants were sprayed with an aqueous solution containing NaNO₃(0.2 mM) and Na₂SO₄(0.2 mM) (pH 5.6, a control variant), or with the same solution, which was acidified to pH 2.5 (acid variant). Functional characteristics were determined by chlorophyll fluorescence analysis. Acid rain application caused reduction in the efficiency of the photosynthetic electron transport by 25%, which was accompanied by an increase by 85% in the quantum yield of thermal dissipation of excess light quanta. Ultrastructural changes in chloroplast were registered by transmission electron microscopy (TEM) after two days of the SAR-treatment of pea leaves. In this case, the changes in the structure of grana, heterogeneity of thylakoids packaging in granum, namely, the increase of intra-thylakoid gaps and thickness of granal thylakoids compared to the control were found. The migration of protein complexes in thylakoid membranes of chloroplasts isolated from leaves treated with SAR was suppressed. It was shown also that carbonic anhydrase activity was inhibited in chloroplast preparations isolated from SAR-treated pea leaves. We proposed a hypothesis on the possible inactivation of thylakoid carbonic anhydrase under SAR and its involvement in the inhibition of photochemical activity of chloroplasts. The data obtained allows to suggest that acid rains negatively affect the photosynthetic apparatus disrupting the membrane system of chloroplast.

  13. Integration of carbon assimilation modes with photosynthetic light capture in the green alga Chlamydomonas reinhardtii.

    Science.gov (United States)

    Berger, Hanna; Blifernez-Klassen, Olga; Ballottari, Matteo; Bassi, Roberto; Wobbe, Lutz; Kruse, Olaf

    2014-10-01

    The unicellular green alga Chlamydomonas reinhardtii is capable of using organic and inorganic carbon sources simultaneously, which requires the adjustment of photosynthetic activity to the prevailing mode of carbon assimilation. We obtained novel insights into the regulation of light-harvesting at photosystem II (PSII) following altered carbon source availability. In C. reinhardtii, synthesis of PSII-associated light-harvesting proteins (LHCBMs) is controlled by the cytosolic RNA-binding protein NAB1, which represses translation of particular LHCBM isoform transcripts. This mechanism is fine-tuned via regulation of the nuclear NAB1 promoter, which is activated when linear photosynthetic electron flow is restricted by CO(2)-limitation in a photoheterotrophic context. In the wild-type, accumulation of NAB1 reduces the functional PSII antenna size, thus preventing a harmful overexcited state of PSII, as observed in a NAB1-less mutant. We further demonstrate that translation control as a newly identified long-term response to prolonged CO(2)-limitation replaces LHCII state transitions as a fast response to PSII over-excitation. Intriguingly, activation of the long-term response is perturbed in state transition mutant stt7, suggesting a regulatory link between the long- and short-term response. We depict a regulatory circuit operating on distinct timescales and in different cellular compartments to fine-tune light-harvesting in photoheterotrophic eukaryotes. © The Author 2014. Published by the Molecular Plant Shanghai Editorial Office in association with Oxford University Press on behalf of CSPB and IPPE, SIBS, CAS.

  14. The Difference of Photosynthetic Responses to the Cadmium Stress Between a Wild Soybean (Glycine soja Sieb. et Zucc.) and a Cultivated Soybean.

    Science.gov (United States)

    Xue, Zhongcai; Gao, Huiyuan

    2017-09-01

    The effects of Cd on a halophyte of Doingying wild soybean (DY-03262) were studied by comparing it with a cultivated soybean (SN-11) via investigating photosynthetic activity, chlorophyll fluorescence and Cd concentrations in leaves after treatment with different concentrations of Cd (0, 50, and 100 μM) for 10 days. There were no significant differences in photosynthetic rate (P N ), actual photochemical efficiency of PSII (Φ PSII ), stomatal conductance (g s ), and photochemical quenching (qP) between the both soybean species without Cd treatment, but they decreased greater in DY-03262 than that in SN-11 leaves after Cd treatment. The study demonstrated that the decrease in P N were significantly correlated with Cd concentrations in the leaves of both soybeans species. The greater decreases in photosynthetic activity of the DY-03262 were due to the higher Cd concentrations in its leaves.

  15. Cigarette smoking, physical activity, and alcohol consumption as predictors of cancer incidence among women at high risk of breast cancer in the NSABP P-1 trial.

    Science.gov (United States)

    Land, Stephanie R; Liu, Qing; Wickerham, D Lawrence; Costantino, Joseph P; Ganz, Patricia A

    2014-05-01

    NSABP P-1 provides an opportunity to examine the association of behavioral factors with prospectively monitored cancer incidence and interactions with tamoxifen. From 1992 to 1997, 13,388 women with estimated 5-year breast cancer risk greater than 1.66% or a history of lobular carcinoma in situ (87% younger than age 65; 67% postmenopausal) were randomly assigned to tamoxifen versus placebo. Invasive breast cancer, lung cancer, colon cancer, and endometrial cancer were analyzed with Cox regression. Predictors were baseline cigarette smoking, leisure-time physical activity, alcohol consumption, and established risk factors. At median 7 years follow-up, we observed 395, 66, 35, and 74 breast cancer, lung cancer, colon cancer, and endometrial cancer, respectively. Women who had smoked were at increased risk of breast cancer (P = 0.007; HR = 1.3 for 15-35 years smoking, HR = 1.6 for ≥ 35 years), lung cancer (P cancer (P breast cancer risk only among women assigned to placebo (P = 0.021 activity main effect, P = 0.013 activity-treatment interaction; HR = 1.4 for the placebo group) and endometrial cancer among all women (P = 0.026, HR = 1.7). Moderate alcohol (>0-1 drink/day) was associated with decreased risk of colon cancer (P = 0.019; HR = 0.35) versus no alcohol. There were no other significant associations between these behaviors and cancer risk. Among women with elevated risk of breast cancer, smoking has an even greater impact on breast cancer risk than observed in past studies in the general population. Women who smoke or are inactive should be informed of the increased risk of multiple types of cancer. ©2014 AACR.

  16. Variabilidade sazonal da relação entre a radiação fotossinteticamente ativa e a radiação global na bacia do rio Doce, Estado de Minas Gerais = Seasonal variability of the relationship between the photosynthetically active radiation and the global radiation at the river Doce basin, Minas Gerais State

    Directory of Open Access Journals (Sweden)

    Antonio José Steidle Neto

    2006-07-01

    Full Text Available O conhecimento da Radiação Fotossinteticamente Ativa (RFA é importante para diferentes áreas relacionadas à fisiologia vegetal e ciências agrárias. Modelos de estimativa de RFA a partir da Radiação Global (Rg são extremamente úteis, visto que a Rg é convencionalmente medida nas estações meteorológicas. Assim, analisou-se a variabilidade sazonal da relação RFA/Rg em cinco áreas localizadas na bacia do rio Doce, Estado de Minas Gerais, considerando-se os períodos secos e chuvosos dos anos de 2001 a 2004. As relações RFA/Rg obtidas para os períodos secos e chuvosos, assim como para todos os dados, apresentaram concordância com as relações determinadas por diversos pesquisadores em diferentes áreas do mundo. Analisando-se os resultados, constatou-se que, de maneira geral,as relações RFA/Rg tendem a ser superiores durante os períodos chuvosos comparativamente aos secos. Por este estudo, pôde-se concluir que existe variação interanual desta relação, demonstrando assim a necessidade de se considerar esta variabilidade para estimaradequadamente a RFA a partir da Rg. The knowledge of the Photosynthetically Active Radiation (PAR is important to different areas of vegetal physiology and agricultural sciences. Estimation models of the PAR based on the Global Radiation (GR are extremely useful, since the GR is conventionally measured atthe meteorological stations. Thus, the seasonal variability of the relationship PAR/GR was analyzed in five areas located at the river Doce basin, Minas Gerais State, Brazil, considering the dry and wet periods of the years 2001 to 2004. The relationships PAR/GR obtained for the dry and wet periods, and also to all data, presented agreement with those ones determined by several researchers in different areas of the world. Results showed that the relationshipsPAR/GR generally tend to be greater during the wet periods when compared with the dry ones. By this work, it could be concluded that

  17. Seasonal response of photosynthetic electron transport and energy dissipation in the eighth year of exposure to elevated atmospheric CO2 (FACE) in Pinus taeda (loblolly pine).

    Science.gov (United States)

    Logan, Barry A; Combs, Andrew; Myers, Kalisa; Kent, Rose; Stanley, Lela; Tissue, David T

    2009-06-01

    To determine the effect of growth under elevated CO(2) partial pressures (pCO(2)) on photosynthetic electron transport and photoprotective energy dissipation, we examined light-saturated net photosynthetic CO(2) assimilation (A(sat)), the capacity for photosynthetic O(2) evolution, chlorophyll fluorescence emission and the pigment composition of upper-canopy loblolly pine needles in the eighth year of exposure to elevated pCO(2) (20 Pa above ambient) at the free-air CO(2) enrichment facility in the Duke Forest. During the summer growing season, A(sat) was 50% higher in current-year needles and 24% higher in year-old needles in elevated pCO(2) in comparison with needles of the same age cohort in ambient pCO(2). Thus, photosynthetic down-regulation at elevated pCO(2) was observed in the summer in year-old needles. In the winter, A(sat) was not significantly affected by growth pCO(2). Reductions in A(sat), the capacity for photosynthetic O(2) evolution and photosystem II (PSII) efficiency in the light-acclimated and fully-oxidized states were observed in the winter when compared to summer. Growth at elevated pCO(2) had no significant effect on the capacity for photosynthetic O(2) evolution, PSII efficiencies in the light-acclimated and fully-oxidized states, chlorophyll content or the size and conversion state of the xanthophyll cycle, regardless of season or needle age cohort. Therefore, we observed no evidence that photosynthetic electron transport or photoprotective energy dissipation responded to compensate for the effects of elevated pCO(2) on Calvin cycle activity.

  18. Seasonal response of photosynthetic electron transport and energy dissipation in the eighth year of exposure to elevated atmospheric CO{sub 2} (FACE) in Pinus taeda (loblolly pine)

    Energy Technology Data Exchange (ETDEWEB)

    Logan, B.A.; Combs, A.; Kent, R.; Stanley, L. [Bowdoin College, Brunswick, ME (United States). Dept. of Biology; Myers, K. [Texas Tech Univ., Lubbock, TX (United States). Dept. of Biological Sciences; Tissue, D.T. [Texas Tech Univ., Lubbock, TX (United States). Dept. of Biological Sciences; Western Sydney Univ., Richmond, NSW (Australia). Centre for Plant and Food Science

    2009-06-15

    This study investigated the biological adaptation of loblolly pine following long-term seasonal exposure to elevated carbon dioxide (CO{sub 2}) partial pressures (pCO{sub 2}). Exposure to elevated atmospheric CO{sub 2} (pCO{sub 2}) usually results in significant stimulation in light-saturated rates of photosynthetic CO{sub 2} assimilation. Plants are protected against photoinhibition by biochemical processes known as photoprotection, including energy dissipation, which converts excess absorbed light energy into heat. This study was conducted in the eighth year of exposure to elevated pCO{sub 2} at the Duke FACE site. The effect of elevated pCO{sub 2} on electron transport and energy dissipation in the pine trees was examined by coupling the analyses of the capacity for photosynthetic oxygen (O{sub 2}) evolution, chlorophyll fluorescence emission and photosynthetic pigment composition with measurements of net photosynthetic CO{sub 2} assimilation (Asat). During the summer growing season, Asat was 50 per cent higher in current-year needles and 24 per cent higher in year-old needles in elevated pCO{sub 2} in comparison with needles of the same age cohort in ambient pCO{sub 2}. Thus, older needles exhibited greater photosynthetic down-regulation than younger needles in elevated pCO{sub 2}. In the winter, Asat was not significantly affected by growth pCO{sub 2}. Asat was lower in winter than in summer. Growth at elevated pCO{sub 2} had no significant effect on the capacity for photosynthetic oxygen evolution, photosystem 2 efficiencies, chlorophyll content or the size and conversion state of the xanthophyll cycle, regardless of season or needle age. There was no evidence that photosynthetic electron transport or photoprotective energy dissipation responded to compensate for the effects of elevated pCO{sub 2} on Calvin cycle activity. 73 refs., 4 figs.

  19. Seasonal response of photosynthetic electron transport and energy dissipation in the eighth year of exposure to elevated atmospheric CO2 (FACE) in Pinus taeda (loblolly pine)

    International Nuclear Information System (INIS)

    Logan, B.A.; Combs, A.; Kent, R.; Stanley, L.; Myers, K.; Tissue, D.T.; Western Sydney Univ., Richmond, NSW

    2009-01-01

    This study investigated the biological adaptation of loblolly pine following long-term seasonal exposure to elevated carbon dioxide (CO 2 ) partial pressures (pCO 2 ). Exposure to elevated atmospheric CO 2 (pCO 2 ) usually results in significant stimulation in light-saturated rates of photosynthetic CO 2 assimilation. Plants are protected against photoinhibition by biochemical processes known as photoprotection, including energy dissipation, which converts excess absorbed light energy into heat. This study was conducted in the eighth year of exposure to elevated pCO 2 at the Duke FACE site. The effect of elevated pCO 2 on electron transport and energy dissipation in the pine trees was examined by coupling the analyses of the capacity for photosynthetic oxygen (O 2 ) evolution, chlorophyll fluorescence emission and photosynthetic pigment composition with measurements of net photosynthetic CO 2 assimilation (Asat). During the summer growing season, Asat was 50 per cent higher in current-year needles and 24 per cent higher in year-old needles in elevated pCO 2 in comparison with needles of the same age cohort in ambient pCO 2 . Thus, older needles exhibited greater photosynthetic down-regulation than younger needles in elevated pCO 2 . In the winter, Asat was not significantly affected by growth pCO 2 . Asat was lower in winter than in summer. Growth at elevated pCO 2 had no significant effect on the capacity for photosynthetic oxygen evolution, photosystem 2 efficiencies, chlorophyll content or the size and conversion state of the xanthophyll cycle, regardless of season or needle age. There was no evidence that photosynthetic electron transport or photoprotective energy dissipation responded to compensate for the effects of elevated pCO 2 on Calvin cycle activity. 73 refs., 4 figs

  20. Changes in photosynthetic carbon metabolism in senescent leaves of chickpea, Cicer arietinum L.

    Directory of Open Access Journals (Sweden)

    Chandrashekhar V. Murumkar

    2014-01-01

    Full Text Available Photosynthetic processes in mature and senescent leaves of chickpea (Cicer arietinum L. have been compared. With age, leaf photosynthetic pigments viz. chlorophyll a, chlorophyll b and carotenoids, and rate of 14°C fixation were considerably affected. Analysis of δ13C, and short term photosynthetic products showed no major change in the path of photosynthetic carbon fixation. Study of long term photosynthetic 14C assimilation revealed that in old senescent leaves, 14C incorporation into organic acid and sugar fractions was enhanced.

  1. Differential response of salt stress on Brassica juncea: photosynthetic performance, pigment, proline, D1 and antioxidant enzymes.

    Science.gov (United States)

    Mittal, Shweta; Kumari, Nilima; Sharma, Vinay

    2012-05-01

    To investigate the ability of sensitive and tolerant variety of Brassica juncea to adapt to a saline environment in a field, we examined the activities of antioxidant enzymes in relation to photosystem II, chlorophyll a fluorescence, photosynthetic pigment concentration, protein (D1) and proline in plants exposed to salt stress. We observed a greater decline in the photosynthetic rate (∆F/Fm') and electron transport rate (ETRsat) and saturating photosynthetically active photo flux density (PPFDsat) under salt stress in var. Urvashi (sensitive variety) than in var. Bio902 (tolerant variety). Var. Urvashi was found to be more sensitive to high salinity. In var. Bio902, chlorophyll a, chlorophyll b and total chlorophyll concentrations were higher than in the sensitive variety. Proline and protein contents were also higher in var. Bio902 as compared to their lower accumulation in var. Urvashi. The improved performance of the var. Bio902 under high salinity was accompanied by an increase in ascorbate peroxidase (APX, EC 1.11.1.11) and catalase (CAT, EC 1.11.1.6), though no salt-dependent increase in the activity of superoxide dismutase (SOD, EC 1.15.1.1) was observed. However, no such increase in APX and CAT was observed in var. Urvashi, though there was significant increase in SOD activity. These results suggest that var. Bio902 is potentially more tolerant to salt damage and is associated with better adaptive responses found in var. Bio902 than var. Urvashi. Increased photoinhibition in var. Urvashi as observed by its reduced thylakoid membrane protein, D1 probably results from the greater photosynthetic damage caused by salt stress than var. Bio902. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  2. Oxygen uncouples light absorption by the chlorosome antenna and photosynthetic electron transfer in the green sulfur bacterium Chlorobium tepidum

    DEFF Research Database (Denmark)

    Frigaard, N-U; Matsuura, K

    1999-01-01

    center as a consequence of the quenching mechanism which is activated by O2. This reversible uncoupling of the chlorosome antenna might prevent formation of toxic reactive oxygen species from photosynthetically produced reductants under aerobic conditions. The green filamentous bacterium Chloroflexus...... aurantiacus also contains chlorosomes but energy transfer from the BChl c and BChl a antennas to the reaction center in this species was not affected by O2....

  3. Electron Paramagnetic Resonance Spectroscopy of Photosynthetic Systems and Inorganic Model Complexes.

    Science.gov (United States)

    Dexheimer, Susan Lynne

    1990-01-01

    This thesis discusses the application of parallel polarization electron paramagnetic resonance (EPR) spectroscopy, a technique sensitive to formally forbidden transitions in high spin states, to the study of the electronic structure of photosynthetic electron transfer centers and related inorganic model complexes. The theoretical basis for the origin of the parallel polarization transitions and the interpretation of the resulting spectra is presented, and experimental aspects of the detection of parallel polarization transitions are discussed. Parallel polarization EPR was used to study inorganic complexes of trivalent manganese that serve as models for the spectroscopic properties of biological electron transfer centers. X-band EPR spectra were detected from non-Kramers spin states of these complexes. EPR spectra of the S = 2 ground states of the mononuclear complexes Mn(III) tris -acetylacetonate and Mn(III) tris-picolinate and a low-lying excited state of the weakly antiferromagnetically coupled binuclear complex Mn_2(III,III) O(O_2CCH_3) _2 (HB(pz)_3) _2 (HB(pz)_3 = hydrotris(1-pyrazolyl)borate) are discussed. The spectra are interpreted using numerical simulations. Application of parallel polarization EPR to photosyntheic systems led to the detection of a new paramagnetic intermediate associated with photosynthetic water oxidation. The parallel polarization EPR signal is assigned to an S = 1 spin state of an exchange-coupled manganese center in the resting (S_1) state of the photosynthetic oxygen-evolving complex. The properties of the S _1 state parallel polarization EPR signal indicate that it corresponds to the reduced form of the species that gives rise to the previously established multiline conventional EPR signal in the light-induced S _2 state, and the behavior of the signal upon advancement to the S_2 state demonstrates the presence of two separate redox-active centers in the oxygen-evolving complex. The implications for the electronic structure of

  4. Sensitivity of the green algae Chlamydomonas reinhardtii to gamma radiation: Photosynthetic performance and ROS formation.

    Science.gov (United States)

    Gomes, Tânia; Xie, Li; Brede, Dag; Lind, Ole-Christian; Solhaug, Knut Asbjørn; Salbu, Brit; Tollefsen, Knut Erik

    2017-02-01

    The aquatic environment is continuously exposed to ionizing radiation from both natural and anthropogenic sources, making the characterization of ecological and health risks associated with radiation of large importance. Microalgae represent the main source of biomass production in the aquatic ecosystem, thus becoming a highly relevant biological model to assess the impacts of gamma radiation. However, little information is available on the effects of gamma radiation on microalgal species, making environmental radioprotection of this group of species challenging. In this context, the present study aimed to improve the understanding of the effects and toxic mechanisms of gamma radiation in the unicellular green algae Chlamydomonas reinhardtii focusing on the activity of the photosynthetic apparatus and ROS formation. Algal cells were exposed to gamma radiation (0.49-1677mGy/h) for 6h and chlorophyll fluorescence parameters obtained by PAM fluorometry, while two fluorescent probes carboxy-H 2 DFFDA and DHR 123 were used for the quantification of ROS. The alterations seen in functional parameters of C. reinhardtii PSII after 6h of exposure to gamma radiation showed modifications of PSII energy transfer associated with electron transport and energy dissipation pathways, especially at the higher dose rates used. Results also showed that gamma radiation induced ROS in a dose-dependent manner under both light and dark conditions. The observed decrease in photosynthetic efficiency seems to be connected to the formation of ROS and can potentially lead to oxidative stress and cellular damage in chloroplasts. To our knowledge, this is the first report on changes in several chlorophyll fluorescence parameters associated with photosynthetic performance and ROS formation in microalgae after exposure to gamma radiation. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Association of physical activities of daily living with the incidence of certified need of care in the long-term care insurance system of Japan: the ROAD study.

    Science.gov (United States)

    Akune, Toru; Muraki, Shigeyuki; Oka, Hiroyuki; Tanaka, Sakae; Kawaguchi, Hiroshi; Tokimura, Fumiaki; Yoshida, Hideyo; Suzuki, Takao; Nakamura, Kozo; Yoshimura, Noriko

    2014-05-01

    The present study aimed to investigate association of physical activities of daily living with the incidence of certified need of care in the national long-term care insurance (LTCI) system in elderly Japanese population-based cohorts. Of the 3,040 participants in the baseline examination, we enrolled 1,773 (699 men, 1,074 women) aged 65 years or older who were not certified as in need of care-level elderly at baseline. Participants were followed during an average of 4.0 years for incident certification of need of care in the LTCI system. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was used assess function. Associated factors in the baseline examination with the occurrence were determined by multivariate Cox proportional hazards regression analysis. Receiver operating characteristic curve analysis was performed to evaluate cut-off values for discriminating between the occurrence and the non-occurrence group. All 17 items in the WOMAC function domain were significantly associated with the occurrence of certified need of care in the overall population. Cut-off values of the WOMAC function score that maximized the sum of sensitivity and specificity were around 4-6 in the overall population, in men, and in women. Multivariate Cox hazards regression analysis revealed that a WOMAC function score ≥4 was significantly associated with occurrence with the highest hazard ratio (HR) for occurrence after adjusting for confounders in the overall population (HR [95 % confidence interval (CI)] 2.54 [1.76-3.67]) and in women [HR (95 % CI) 3.13 (1.95-5.02)]. A WOMAC function score ≥5 was significantly associated with the highest HR for occurrence in men [HR (95 % CI) 1.88 (1.03-3.43)]. Physical dysfunction in daily living is a predictor of the occurrence of certified need of care. Elderly men with a WOMAC function score ≥5 and women with a score ≥4 should undergo early intervention programs to prevent subsequent deterioration.

  6. Photosynthetic and enzymatic metabolism of Schinus terebinthifolius Raddi seedlings under water deficit

    Directory of Open Access Journals (Sweden)

    Danieli Pieretti Nunes

    Full Text Available ABSTRACT Schinus terebinthifolius Raddi is a tree species that can be used in the recovery of degraded areas, as it exhibits rapid growth and has a very expansive root system, facilitating water uptake from the deeper layers of the soil. The objective of this study was to evaluate photosynthesis and enzymatic activity in S. terebinthifolius seedlings under conditions of water deficit and their potential to recover following re-irrigation. The experiment was conducted in a greenhouse under a plastic covering where plants were distributed into two groups: Group 1 - control plants, where irrigation was maintained at 70% of the water retention capacity, and Group 2 - stressed plants, where irrigation was suspended until the photosynthetic rate neared zero, followed by rehydration for 12 days, then a further suspension of irrigation. At the beginning of the experiment and during the suspension of irrigation and rehydration, plants were evaluated for gas and antioxidant enzyme exchanges. Hydric stress significantly reduced photosynthesis, stomatal transpiration conductance, carboxylation efficiency of Rubisco, and the chlorophyll content of the S. terebinthifolius plants. Following rehydration, plants recovered the carboxylation efficiency of Rubisco, but not the photosynthetic rate. Antioxidant enzyme activity increased in both the aerial part and the root in response to water deficit.

  7. The temporal and species dynamics of photosynthetic acclimation in flag leaves of rice (Oryza sativa) and wheat (Triticum aestivum) under elevated carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, J.; Zeng, Q.; Xie, Z.; Tang, H.; Zhu, C. (Chinese Academy of Sciences. State Key Lab. of Soil and Sustainable Agriculture, Institute of Soil Science, Nanjing (China)); Hasegawa, T. (National Institute for Agro-Environmental Sciences. Agro-Meteorology Div., Tsukuba (Japan)); Ziska, L. (Crop Systems and Global Change Lab., Beltsville, MD (United States)); Jia, X. (Chinese Academic of Sciences/Nanjing Botanical Garden Memorial Sun Yat-Sen. Jiangsu Institute of Botany, Nanjing (China))

    2012-07-15

    In this study, we tested for the temporal occurrence of photosynthetic acclimation to elevated [CO{sub 2}] in the flag leaf of two important cereal crops, rice and wheat. In order to characterize the temporal onset of acclimation and the basis for any observed decline in photosynthetic rate, we characterized net photosynthesis, g{sub s}, g{sub m}, C{sub i}/C{sub a}, C{sub i}/C{sub c}, V{sub cmax}, J{sub max}, cell wall thickness, content of Rubisco, cytochrome (Cyt) f, N, chlorophyll and carbohydrate, mRNA expression for rbcL and petA, activity for Rubisco, sucrose phosphate synthase (SPS) and sucrose synthase (SS) at full flag expansion, mid-anthesis and the late grain-filling stage. No acclimation was observed for either crop at full flag leaf expansion. However, at the mid-anthesis stage, photosynthetic acclimation in rice was associated with RuBP carboxylation and regeneration limitations, while wheat only had the carboxylation limitation. By grain maturation, the decline of Rubisco content and activity had contributed to RuBP carboxylation limitation of photosynthesis in both crops at elevated [CO{sub 2}]; however, the sharp decrease of Rubisco enzyme activity played a more important role in wheat. Although an increase in non-structural carbohydrates did occur during these later stages, it was not consistently associated with changes in SPS and SS or photosynthetic acclimation. Rather, over time elevated [CO{sub 2}] appeared to enhance the rate of N degradation and senescence so that by late-grain fill, photosynthetic acclimation to elevated [CO{sub 2}] in the flag leaf of either species was complete. These data suggest that the basis for photosynthetic acclimation with elevated [CO{sub 2}] may be more closely associated with enhanced rates of senescence, and, as a consequence, may be temporally dynamic, with significant species variation. (Author)

  8. Non-Hermitian exciton dynamics in a photosynthetic unit system

    Science.gov (United States)

    Thilagam, A.

    2012-02-01

    The non-Hermitian quantum dynamics of excitonic energy transfer in photosynthetic systems is investigated using a dissipative two-level dimer model. The approach is based on Green's function formalism which permits consideration of decoherence and intersite transfer processes on comparable terms. The results indicate a combination of coherent and incoherent behavior at higher temperatures with the possibility of exceptional points occurring at the coherent-incoherent crossover regime at critical temperatures. When each dimer site is coupled equally to the environmental sources of dissipation, the excitonic wavepacket evolves with time with a coherent component, which can be attributed to the indistinguishability of the sources of dissipation. The time evolution characteristics of the B850 Bchls dimer system is analysed using typical parameter estimates in photosynthetic systems, and the quantum brachistochrone passage times are obtained for a range of parameters.

  9. Photosynthetic Energy Transfer at the Quantum/Classical Border.

    Science.gov (United States)

    Keren, Nir; Paltiel, Yossi

    2018-04-03

    Quantum mechanics diverges from the classical description of our world when very small scales or very fast processes are involved. Unlike classical mechanics, quantum effects cannot be easily related to our everyday experience and are often counterintuitive to us. Nevertheless, the dimensions and time scales of the photosynthetic energy transfer processes puts them close to the quantum/classical border, bringing them into the range of measurable quantum effects. Here we review recent advances in the field and suggest that photosynthetic processes can take advantage of the sensitivity of quantum effects to the environmental 'noise' as means of tuning exciton energy transfer efficiency. If true, this design principle could be a base for 'nontrivial' coherent wave property nano-devices. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Photosynthetic production of diterpenoids in chloroplasts and cyanobacteria

    DEFF Research Database (Denmark)

    Vavitsas, Konstantinos

    on the potential of using plant chloroplasts and cyanobacteria as biosynthetic vessels, with a focus on diterpenoid production, and on the potential direct linking of photosynthesis to drive electron-consuming enzymes, such as the monooxygenases cytochrome P450s. I subsequently present the full localization...... be further modified by cyclizing enzymes, and be decorated by the addition of chemical groups. Even though they are mainly plant-derived compounds, diterpenoid production in photosynthetic organisms is rather unexplored, with a few successful studies reported in the literature. In this thesis, I elaborate...... and be assembled correctly by its native homologous recombination mechanisms. This theoretical and experimental work puts together the existing knowledge on terpenoid production and photosynthetic biotechnology, reveals the existing limitations and potential bottlenecks, and paves the way for future work towards...

  11. Photosynthetic costs and benefits of abaxial versus adaxial anthocyanins in Colocasia esculenta 'Mojito'.

    Science.gov (United States)

    Hughes, Nicole M; Carpenter, Kaylyn L; Keidel, Timothy S; Miller, Charlene N; Waters, Matthew N; Smith, William K

    2014-11-01

    Anthocyanins in upper (adaxial) leaf tissues provide greater photoprotection than in lower (abaxial) tissues, but also predispose tissues to increased shade acclimation and, consequently, reduced photosynthetic capacity. Abaxial anthocyanins may be a compromise between these costs/benefits. Plants adapted to shaded understory environments often exhibit red/purple anthocyanin pigmentation in lower (abaxial) leaf surfaces, but rarely in upper (adaxial) surfaces. The functional significance of this color pattern in leaves is poorly understood. Here, we test the hypothesis that abaxial anthocyanins protect leaves of understory plants from photo-oxidative stress via light attenuation during periodic exposure to high incident sunlight in the forest understory, without interfering with sunlight capture and photosynthesis during shade conditions. We utilize a cultivar of Colocasia esculenta exhibiting adaxial and abaxial anthocyanin variegation within individual leaves to compare tissues with the following color patterns: green adaxial, green abaxial (GG), green adaxial, red abaxial (GR), red adaxial, green abaxial (RG), and red adaxial, red abaxial (RR). Consistent with a photoprotective function of anthocyanins, tissues exhibited symptoms of increasing photoinhibition in the order (from least to greatest): RR, RG, GR, GG. Anthocyanic tissues also showed symptoms of shade acclimation (higher total chl, lower chl a/b) in the same relative order. Inconsistent with our hypothesis, we did not observe any differences in photosynthetic CO2 uptake under shade conditions between the tissue types. However, GG and GR had significantly (39 %) higher photosynthesis at saturating irradiance (A sat) than RG and RR. Because tissue types did not differ in nitrogen content, these patterns likely reflect differences in resource allocation at the tissue level, with greater nitrogen allocated toward energy processing in GG and GR, and energy capture in RG and RR (consistent with relative

  12. Modeling the dynamic modulation of light energy in photosynthetic algae.

    Science.gov (United States)

    Papadakis, Ioannis A; Kotzabasis, Kiriakos; Lika, Konstadia

    2012-05-07

    An integrated cell-based dynamic mathematical model that take into account the role of the photon absorbing process, the partition of excitation energy, and the photoinactivation and repair of photosynthetic units, under variable light and dissolved inorganic carbon (DIC) availability is proposed. The modeling of the photon energy absorption and the energy dissipation is based on the photoadaptive changes of the underlying mechanisms. The partition of the excitation energy is based on the relative availability of light and DIC to the cell. The modeling of the photoinactivation process is based on the common aspect that it occurs under any light intensity and the modeling of the repair process is based on the evidence that it is controlled by chloroplast and nuclear-encoded enzymes. The present model links the absorption of photons and the partitioning of excitation energy to the linear electron flow and other quenchers with chlorophyll fluorescence emission parameters, and the number of the functional photosynthetic units with the photosynthetic oxygen production rate. The energy allocation to the LEF increases as DIC availability increases and/or light intensity decreases. The rate of rejected energy increases with light intensity and with DIC availability. The resulting rate coefficient of photoinactivation increases as light intensity and/or as DIC concentration increases. We test the model against chlorophyll fluorescence induction and photosynthetic oxygen production rate measurements, obtained from cultures of the unicellular green alga Scenedesmus obliquus, and find a very close quantitative and qualitative correspondence between predictions and data. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Microbiological Hydrogen Production by Anaerobic Fermentation and Photosynthetic Process

    International Nuclear Information System (INIS)

    Asada, Y.; Ohsawa, M.; Nagai, Y.; Fukatsu, M.; Ishimi, K.; Ichi-ishi, S.

    2009-01-01

    Hydrogen gas is a clean and renewable energy carrier. Microbiological hydrogen production from glucose or starch by combination used of an anaerobic fermenter and a photosynthetic bacterium, Rhodobacter spheroides RV was studied. In 1984, the co-culture of Clostridium butyricum and RV strain to convert glucose to hydrogen was demonstrated by Miyake et al. Recently, we studied anaerobic fermentation of starch by a thermophilic archaea. (Author)

  14. Advances in Metabolic Engineering of Cyanobacteria for Photosynthetic Biochemical Production

    OpenAIRE

    Lai, Martin C.; Lan, Ethan I.

    2015-01-01

    Engineering cyanobacteria into photosynthetic microbial cell factories for the production of biochemicals and biofuels is a promising approach toward sustainability. Cyanobacteria naturally grow on light and carbon dioxide, bypassing the need of fermentable plant biomass and arable land. By tapping into the central metabolism and rerouting carbon flux towards desirable compound production, cyanobacteria are engineered to directly convert CO2 into various chemicals. This review discusses the d...

  15. Enhanced Practical Photosynthetic CO2 Mitigation. Quarterly Technical Report

    International Nuclear Information System (INIS)

    Gregory Kremer; David J. Bayless; Morgan Vis; Michael Prudich; Keith Cooksey; Jeff Muhs

    2005-01-01

    This report highlights significant achievements in the Enhanced Practical Photosynthetic CO 2 Mitigation Project during the ending 12/31/2004. Specific results and accomplishments for the program include review of pilot scale testing and design of a new bioreactor. Testing confirmed that algae can be grown in a sustainable fashion in the pilot bioreactor, even with intermittent availability of sunlight. The pilot-scale tests indicated that algal growth rate followed photon delivery during productivity testing

  16. Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors.

    Science.gov (United States)

    Bonnineau, Chloé; Sague, Irene Gallardo; Urrea, Gemma; Guasch, Helena

    2012-05-01

    In multiple stress situations, the co-occurrence of environmental and chemical factors can influence organisms' ability to cope with toxicity. In this context, the influence of light adaptation on the response of freshwater biofilms to sudden light changes or to herbicides exposure was investigated by determining various parameters: diatom community composition, photosynthetic parameters, chlorophyll a content, antioxidant enzyme activities. Biofilms were grown in microcosms under sub-optimal, saturating, and high light intensities and showed already described characteristics of shade/light adaptation (community structure, photosynthetic adaptation, etc.). Light history modulated antioxidant and photosynthetic responses of biofilms to the stress caused by short-term exposure to sudden light changes or to herbicides. First biofilms adapted to sub-optimal light intensity (shade-adapted) were found to be more sensitive to an increase in light intensity than high-light adapted ones to a reduction in light intensity. Second, while light history influenced biofilms' response to glyphosate, it had little influence on biofilms' response to copper and none on its response to oxyfluorfen. Indeed glyphosate exposure led to a stronger decrease in photosynthetic efficiency of shade-adapted biofilms (EC(50) = 11.7 mg L(-1)) than of high-light adapted communities (EC(50) = 35.6 mg L(-1)). Copper exposure led to an activation of ascorbate peroxidase (APX) in biofilms adapted to sub-optimal and saturating light intensity while the protein content decreased in all biofilms exposed to copper. Oxyfluorfen toxicity was independent of light history provoking an increase in APX activity. In conclusion this study showed that both previous exposure to contaminants and physical habitat characteristics might influence community tolerance to disturbances strongly.

  17. The role of energy losses in photosynthetic light harvesting

    International Nuclear Information System (INIS)

    Krüger, T P J; Van Grondelle, R

    2017-01-01

    Photosynthesis operates at the bottom of the food chain to convert the energy of light into carbohydrates at a remarkable global rate of about 130 TW. Nonetheless, the overall photosynthetic process has a conversion efficiency of a few percent at best, significantly less than bottom-up photovoltaic cells. The primary photosynthetic steps, consisting of light harvesting and charge separation, are often presented as having near-unity quantum efficiency but this holds only true under ideal conditions. In this review, we discuss the importance of energy loss mechanisms to establish robustness in photosynthetic light harvesting. Thermal energy dissipation of light-harvesting complexes (LHCs) in different environments is investigated and the relationships and contrasts between concentration quenching of high pigment concentrations, photoprotection (non-photochemical quenching), quenching due to protein aggregation, and fluorescence blinking are discussed. The role of charge-transfer states in light harvesting and energy dissipation is highlighted and the importance of controlled protein structural disorder to switch the light-harvesting antennae between effective light harvesters and efficient energy quenchers is underscored. The main LHC of plants, LHCII, is used as a prime example. (topical review)

  18. Photosynthetic Reaction Centres – from Basic Research to Application Possibilities

    Directory of Open Access Journals (Sweden)

    Krisztina NAGY

    2010-06-01

    Full Text Available There is no doubt that studying the photosynthetic conversion of light into chemical energy is extremely important in many points of view: 1 technical-in order to improve the utilization of the solar energy; 2 food production – to improve the photosynthetic production of plants in agriculture; 3 ecology – keeping the primer production in ecosystems in the biosphere balanced, etc. In the photosynthetic reaction centre protein, RC, light energy is converted by a quantum yield of almost unity. There is no such a system designed by human which is able to do that. The RC purified from purple bacteria provides an extremely unique system for studying the requirements for high efficiency conversion of light into electrochemical energy. Thanks to the recent structural (e.g. crystallography (Nobel prize to Michel, Deisenhofer, Huber and functional (Nobel prize to Marcus results together with the works of molecular biology, computer- and electro-techniques, a wealth of information made a relatively clear picture about the kinetics, energetics and stabilization of electron transport within this protein that opens possibilities for new generation practical applications. In this paper we provide a short summary of fields in which the reaction centre protein can be important from practical points of view.

  19. Photosynthetic efficiency of Pedunculate oak seedlings under simulated water stress

    Directory of Open Access Journals (Sweden)

    Popović Zorica

    2010-01-01

    Full Text Available Photosynthetic performance of seedlings of Quercus robur exposed to short-term water stress in the laboratory conditions was assessed through the method of induced fluorometry. The substrate for seedlings was clayey loam, with the dominant texture fraction made of silt, followed by clay and fine sand, with total porosity 68.2%. Seedlings were separated in two groups: control (C (soil water regime in pots was maintained at the level of field water capacity and treated (water-stressed, WS (soil water regime was maintained in the range of wilting point and lentocapillary capacity. The photosynthetic efficiency was 0.642±0.25 and 0.522±0.024 (WS and C, respectively, which was mostly due to transplantation disturbances and sporadic leaf chlorosis. During the experiment Fv/Fm decreased in both groups (0.551±0.0100 and 0.427±0.018 in C and WS, respectively. Our results showed significant differences between stressed and control group, in regard to both observed parameters (Fv/Fm and T½. Photosynthetic efficiency of pedunculate oak seedlings was significantly affected by short-term water stress, but to a lesser extent than by sufficient watering.

  20. Photosynthetic temperature responses of Eucalyptus globulus and Eucalyptus nitens

    Energy Technology Data Exchange (ETDEWEB)

    Battaglia, M.; Beadle, C. [Commonwealth Scientific and Industrial Research Organization (CSIRO), Canberra, ACT (Australia). Div. of Forestry and Forest Products; Loughead, S. [Tasmania Univ., Hobart, TAS (Australia)

    1996-01-01

    Photosynthetic responses to temperature variations of four year old Eucalyptus globulus and Eucalyptus nitens were investigated. Temperatures varied between 10 degrees C and 35 degrees C, and were measured at approximately monthly intervals from early spring until midwinter. The photosynthetic temperature optimum was found to be linearly related to the average temperature of the preceding week during the entire nine month period. For E. globulus the optimum temperature for net photosynthesis increased from 17 degrees C to 23 degrees C as the mean daily temperature increased from 7 degrees C to 16 degrees. The corresponding values for E. nitens were 14 to 20 degrees C as the mean daily temperature increased from 7 to 19 degrees C. The photosynthetic performance of E. nitens was less sensitive to temperatures above and below the optimum than E. globulus. In a second experiment E. globulus clones were acclimated in temperature-controlled greenhouses, and in a shadehouse in four climatically different regions of Tasmania. A comparison of light response curves of the plants showed that the maximum rate of net photosynthesis was affected by the growth temperature, whereas apparent quantum efficiency remained unchanged. 25 refs., 3 tabs., 8 figs.

  1. PHOTOSYNTHETIC PIGMENTS IN HEVEA CLONES UNDER POWDERY MILDEW ATTACK

    Directory of Open Access Journals (Sweden)

    Gisely Cristina Gonzalez

    2013-08-01

    Full Text Available http://dx.doi.org/10.5902/1980509810561The rubber tree [Hevea brasiliensis (Willd. ex Adr. Of Juss. Muell. Arg.] can be affected by the occurrence of the fungus Oidium heveae, which causes one of the most important diseases of rubber trees, powdery mildew. This work studied meet changes in photosynthetic pigments, an indicator of oxidative stress, in seedlings of three Hevea brasiliensis clones, RRIM 600, GT1 and PR255, under infection in Oidium heveae. The experiment was conducted in an open environment under natural photoperiod conditions and at the beginning of the trial, the rubber plants would be inoculated were sprayed with an aqueous suspension containing O. heveae at a concentration of 16 x 104 conidia mL-1. On the day of inoculation and after 48, 96, 144 and 192 h leaf samples were collected for the determination of photosynthetic pigments. Degradation in photosynthetic pigments in the period of infection was observed in rubber tree clones studied; thus, there is oxidative stress in clones of rubber trees. No promising genetic material for genetic improvement work stress tolerance by Oidium heveae was identified.

  2. Photosynthetic Reaction Centres-from Basic Research to Application

    Directory of Open Access Journals (Sweden)

    László NAGY

    2010-06-01

    Full Text Available There is no doubt that studying the photosynthetic conversion of light into chemical energy is extremely important in many points of view; e.g., 1 technical-in order to improve the utilization of the solar energy; 2 food production-to improve the photosynthetic production of plants in agriculture; 3 ecology-keeping the primer production in ecosystems in the biosphere balanced, etc. In the photosynthetic reaction centre protein, RC, light energy is converted by a quantum yield of almost unity. There is no such a system designed by human which is able to do that. The RC purified from purple bacteria provides an extremely unique system for studying the requirements for high efficiency conversion of light into electrochemical energy. Thanks to the recent structural (e.g. crystallography (Nobel prize to Michel, Deisenhofer, Huber and functional (Nobel prize to Marcus results together with the works of molecular biology, computer- and electro-techniques, a wealth of information made a relatively clear picture about the kinetics, energetics and stabilization of electron transport within this protein that opens possibilities for new generation practical applications. In this paper we provide a short summary of fields in which the reaction centre protein can be important from practical points of view.

  3. DAILY BUDGETS OF PHOTOSYNTHETICALLY FIXED CARBON IN SYMBIOTIC ZOANTHIDS.

    Science.gov (United States)

    Steen, R Grant; Muscatine, L

    1984-10-01

    We tested the hypothesis that some zoanthids are able to meet a portion of their daily respiratory carbon requirement with photosynthetic carbon from symbiotic algal cells (= zooxanthellae). A daily budget was constructed for carbon (C) photosynthetically fixed by zooxanthellae of the Bermuda zoanthids Zoanthus sociatus and Palythoa variabilis. Zooxanthellae have an average net photosynthetic C fixation of 7.48 and 15.56 µgC·polyp -1 ·day -1 for Z. sociatus and P. variabilis respectively. The C-specific growth rate (µ c ) was 0.215·day -1 for Z. sociatus and 0.152·day -1 for P. variabilis. The specific growth rate (µ) of zooxanthellae in the zoanthids was measured to be 0.011 and 0.017·day -1 for Z. sociatus and P. variabilis zooxanthellae respectively. Z. sociatus zooxanthellae translocated 95.1% of the C assimilated in photosynthesis, while P. variabilis zooxanthellae translocated 88.8% of their fixed C. As the animal tissue of a polyp of Z. sociatus required 14.75 µgC·day -1 for respiration, and one of P. variabiis required 105.54 µgC·day -1 , the contribution of zooxanthellae to animal respiration (CZAR) was 48.2% for Z. sociatus and 13.1% for P. variabilis.

  4. The role of energy losses in photosynthetic light harvesting

    Science.gov (United States)

    Krüger, T. P. J.; van Grondelle, R.

    2017-07-01

    Photosynthesis operates at the bottom of the food chain to convert the energy of light into carbohydrates at a remarkable global rate of about 130 TW. Nonetheless, the overall photosynthetic process has a conversion efficiency of a few percent at best, significantly less than bottom-up photovoltaic cells. The primary photosynthetic steps, consisting of light harvesting and charge separation, are often presented as having near-unity quantum efficiency but this holds only true under ideal conditions. In this review, we discuss the importance of energy loss mechanisms to establish robustness in photosynthetic light harvesting. Thermal energy dissipation of light-harvesting complexes (LHCs) in different environments is investigated and the relationships and contrasts between concentration quenching of high pigment concentrations, photoprotection (non-photochemical quenching), quenching due to protein aggregation, and fluorescence blinking are discussed. The role of charge-transfer states in light harvesting and energy dissipation is highlighted and the importance of controlled protein structural disorder to switch the light-harvesting antennae between effective light harvesters and efficient energy quenchers is underscored. The main LHC of plants, LHCII, is used as a prime example.

  5. Evidence That Putrescine Modulates the Higher Plant Photosynthetic Proton Circuit

    Science.gov (United States)

    Kotzabasis, Kiriakos; Kramer, David M.

    2012-01-01

    The light reactions of photosynthesis store energy in the form of an electrochemical gradient of protons, or proton motive force (pmf), comprised of electrical (Δψ) and osmotic (ΔpH) components. Both components can drive the synthesis of ATP at the chloroplast ATP synthase, but the ΔpH component also plays a key role in regulating photosynthesis, down-regulating the efficiency of light capture by photosynthetic antennae via the qE mechanism, and governing electron transfer at the cytochrome b6f complex. Differential partitioning of pmf into ΔpH and Δψ has been observed under environmental stresses and proposed as a mechanism for fine-tuning photosynthetic regulation, but the mechanism of this tuning is unknown. We show here that putrescine can alter the partitioning of pmf both in vivo (in Arabidopsis mutant lines and in Nicotiana wild type) and in vitro, suggesting that the endogenous titer of weak bases such as putrescine represents an unrecognized mechanism for regulating photosynthetic responses to the environment. PMID:22253808

  6. Photovoltaic concepts inspired by coherence effects in photosynthetic systems

    KAUST Repository

    Bredas, Jean-Luc

    2016-12-20

    The past decade has seen rapid advances in our understanding of how coherent and vibronic phenomena in biological photosynthetic systems aid in the efficient transport of energy from light-harvesting antennas to photosynthetic reaction centres. Such coherence effects suggest strategies to increase transport lengths even in the presence of structural disorder. Here we explore how these principles could be exploited in making improved solar cells. We investigate in depth the case of organic materials, systems in which energy and charge transport stand to be improved by overcoming challenges that arise from the effects of static and dynamic disorder-structural and energetic-and from inherently strong electron-vibration couplings. We discuss how solar-cell device architectures can evolve to use coherence-exploiting materials, and we speculate as to the prospects for a coherent energy conversion system. We conclude with a survey of the impacts of coherence and bioinspiration on diverse solar-energy harvesting solutions, including artificial photosynthetic systems.

  7. Continuous cultivation of photosynthetic microorganisms: Approaches, applications and future trends.

    Science.gov (United States)

    Fernandes, Bruno D; Mota, Andre; Teixeira, Jose A; Vicente, Antonio A

    2015-11-01

    The possibility of using photosynthetic microorganisms, such as cyanobacteria and microalgae, for converting light and carbon dioxide into valuable biochemical products has raised the need for new cost-efficient processes ensuring a constant product quality. Food, feed, biofuels, cosmetics and pharmaceutics are among the sectors that can profit from the application of photosynthetic microorganisms. Biomass growth in a photobioreactor is a complex process influenced by multiple parameters, such as photosynthetic light capture and attenuation, nutrient uptake, photobioreactor hydrodynamics and gas-liquid mass transfer. In order to optimize productivity while keeping a standard product quality, a permanent control of the main cultivation parameters is necessary, where the continuous cultivation has shown to be the best option. However it is of utmost importance to recognize the singularity of continuous cultivation of cyanobacteria and microalgae due to their dependence on light availability and intensity. In this sense, this review provides comprehensive information on recent breakthroughs and possible future trends regarding technological and process improvements in continuous cultivation systems of microalgae and cyanobacteria, that will directly affect cost-effectiveness and product quality standardization. An overview of the various applications, techniques and equipment (with special emphasis on photobioreactors) in continuous cultivation of microalgae and cyanobacteria are presented. Additionally, mathematical modeling, feasibility, economics as well as the applicability of continuous cultivation into large-scale operation, are discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Absorption of 32P-phosphate and photosynthetic 14CO2 fixation in mulberry attacked by the root-knot nematoda, Meloidogyne mali

    International Nuclear Information System (INIS)

    Toida, Yukio; Yamashita, Tadaaki

    1985-01-01

    Radioactive phosphate was applied to mulberry plants infected with the root-knot nematode, Meloidogyne mali, to analyze root uptake and translocation into leaves. A much larger accumulation of 32 P was observed in the roots and leaves on the upper part of the stem in the infected plant than in the uninfected one. The photosynthetic activity measured by the short-term 14 CO 2 fixation by a leaf segment in the leaf of the infected plant was half that of the uninfected plant. However, no significant differences in the percentage distribution of 14 C in various photosynthetic products were recognized, and main 14 C compounds consist of alanine of serine in the leaves of both plant. It was suggested that the low growth performance and dwarfing in the mulberry plant attacked by the nematode were caused by the remarkable increase of phosphate uptake under the limited supply of photosynthetic products. (author)

  9. Peak levels of endogenous cytokinins after decapitation in leaves of leguminous plants: increase of protein and chlorophyll contents and photosynthetic 14CO2 fixation

    International Nuclear Information System (INIS)

    Pozsar, B.I.

    1980-01-01

    The side-effects of endogenous cytokinins were examined in leguminous plants (beans, alfalfa). Two weeks after decapitation the cytokinin-content of the leaves increased approx. 8-fold. Parallel to this, the total N-content increased by 30%, the protein N-content by 70%, the chlorophyll-content by 40% and the photosynthetic 14 CO 2 fixation by 100%. Thus, in addition to the mitotic activity, the protein-synthesis and photosynthetic CO 2 fixation are also enhanced by endogenous cytokinins. (L.E.)

  10. Molecular and Photosynthetic Responses to Prolonged Darkness and Subsequent Acclimation to Re-Illumination in the Diatom Phaeodactylum tricornutum

    DEFF Research Database (Denmark)

    Nymark, Marianne; Valle, Kristi Collier; Hancke, Kasper

    2013-01-01

    transcriptional profiling, pigment analyses, imaging and photo-physiological measurements. The responses were studied during continuous white light, after 48 h of dark treatment and after 0.5 h, 6 h, and 24 h of re-exposure to the initial irradiance. The analyses resulted in several intriguing findings. Dark...... treatment of the cells led to 1) significantly decreased nuclear transcriptional activity, 2) distinct intracellular changes, 3) fixed ratios of the light-harvesting pigments despite a decrease in the total cell pigment pool, and 4) only a minor drop in photosynthetic efficiency (ΦPSII_max). Re......-introduction of the cells to the initial light conditions revealed 5) distinct expression profiles for nuclear genes involved in photosynthesis and those involved in photoprotection, 6) rapid rise in photosynthetic parameters (α and rETRmax) within 0.5 h of re-exposure to light despite a very modest de novo synthesis...

  11. Simulation of the Unexpected Photosynthetic Seasonality in Amazonian Evergreen Forests by Using an Improved Diffuse Fraction-Based Light Use Efficiency Model

    Science.gov (United States)

    Yan, Hao; Wang, Shao-Qiang; da Rocha, Humberto R.; Rap, Alexandru; Bonal, Damien; Butt, Nathalie; Coupe, Natalia Restrepo; Shugart, Herman H.

    2017-11-01

    Understanding the mechanism of photosynthetic seasonality in Amazonian evergreen forests is critical for its formulation in global climate and carbon cycle models. However, the control of the unexpected photosynthetic seasonality is highly uncertain. Here we use eddy-covariance data across a network of Amazonian research sites and a novel evapotranspiration (E) and two-leaf-photosynthesis-coupled model to investigate links between photosynthetic seasonality and climate factors on monthly scales. It reproduces the GPP seasonality (R2 = 0.45-0.69) with a root-mean-square error (RMSE) of 0.67-1.25 g C m-2 d-1 and a Bias of -0.03-1.04 g C m-2 d-1 for four evergreen forest sites. We find that the proportion of diffuse and direct sunlight governs the photosynthetic seasonality via their interaction with sunlit and shaded leaves, supported by a proof that canopy light use efficiency (LUE) has a strong linear relationship with the fraction of diffuse sunlight for Amazonian evergreen forests. In the transition from