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Sample records for purple photosynthetic bacteria

  1. Synthesis of High-Molecular-Weight Polyhydroxyalkanoates by Marine Photosynthetic Purple Bacteria

    Science.gov (United States)

    Higuchi-Takeuchi, Mieko; Morisaki, Kumiko; Toyooka, Kiminori; Numata, Keiji

    2016-01-01

    Polyhydroxyalkanoate (PHA) is a biopolyester/bioplastic that is produced by a variety of microorganisms to store carbon and increase reducing redox potential. Photosynthetic bacteria convert carbon dioxide into organic compounds using light energy and are known to accumulate PHA. We analyzed PHAs synthesized by 3 purple sulfur bacteria and 9 purple non-sulfur bacteria strains. These 12 purple bacteria were cultured in nitrogen-limited medium containing acetate and/or sodium bicarbonate as carbon sources. PHA production in the purple sulfur bacteria was induced by nitrogen-limited conditions. Purple non-sulfur bacteria accumulated PHA even under normal growth conditions, and PHA production in 3 strains was enhanced by nitrogen-limited conditions. Gel permeation chromatography analysis revealed that 5 photosynthetic purple bacteria synthesized high-molecular-weight PHAs, which are useful for industrial applications. Quantitative reverse transcription polymerase chain reaction analysis revealed that mRNA levels of phaC and PhaZ genes were low under nitrogen-limited conditions, resulting in production of high-molecular-weight PHAs. We conclude that all 12 tested strains are able to synthesize PHA to some degree, and we identify 5 photosynthetic purple bacteria that accumulate high-molecular-weight PHA molecules. Furthermore, the photosynthetic purple bacteria synthesized PHA when they were cultured in seawater supplemented with acetate. The photosynthetic purple bacteria strains characterized in this study should be useful as host microorganisms for large-scale PHA production utilizing abundant marine resources and carbon dioxide. PMID:27513570

  2. Spectroscopy of Single Light-Harvesting Complexes from Purple Photosynthetic Bacteria at 1.2 K

    NARCIS (Netherlands)

    Oijen, A.M. van; Ketelaars, M.; Köhler, J.; Aartsma, T.J.; Schmidt, J.

    1998-01-01

    In this Letter we present the first observation of the fluorescence-excitation spectra of individual light-harvesting complexes (LH2) from purple photosynthetic bacteria at 1.2 K. The spectra reveal the electronic transitions to the individual excitonic states of the assembly of absorbing

  3. Spectroscopy of Single Light-Harvesting Complexes from Purple Photosynthetic Bacteria at 1.2 K

    NARCIS (Netherlands)

    Oijen, A.M. van; Ketelaars, M.; Köhler, J.; Aartsma, T.J.; Schmidt, J.

    1998-01-01

    In this Letter we present the first observation of the fluorescence-excitation spectra of individual light-harvesting complexes (LH2) from purple photosynthetic bacteria at 1.2 K. The spectra reveal the electronic transitions to the individual excitonic states of the assembly of absorbing bacterioch

  4. 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.

  5. Membrane development in purple photosynthetic bacteria in response to alterations in light intensity and oxygen tension.

    Science.gov (United States)

    Niederman, Robert A

    2013-10-01

    Studies on membrane development in purple bacteria during adaptation to alterations in light intensity and oxygen tension are reviewed. Anoxygenic phototrophic such as the purple α-proteobacterium Rhodobacter sphaeroides have served as simple, dynamic, and experimentally accessible model organisms for studies of the photosynthetic apparatus. A major landmark in photosynthesis research, which dramatically illustrates this point, was provided by the determination of the X-ray structure of the reaction center (RC) in Blastochloris viridis (Deisenhofer and Michel, EMBO J 8:2149-2170, 1989), once it was realized that this represented the general structure for the photosystem II RC present in all oxygenic phototrophs. This seminal advance, together with a considerable body of subsequent research on the light-harvesting (LH) and electron transfer components of the photosynthetic apparatus has provided a firm basis for the current understanding of how phototrophs acclimate to alterations in light intensity and quality. Oxygenic phototrophs adapt to these changes by extensive thylakoid membrane remodeling, which results in a dramatic supramolecular reordering to assure that an appropriate flow of quinone redox species occurs within the membrane bilayer for efficient and rapid electron transfer. Despite the high level of photosynthetic unit organization in Rba. sphaeroides as observed by atomic force microscopy (AFM), fluorescence induction/relaxation measurements have demonstrated that the addition of the peripheral LH2 antenna complex in cells adapting to low-intensity illumination results in a slowing of the rate of electron transfer turnover by the RC of up to an order of magnitude. This is ascribed to constraints in quinone redox species diffusion between the RC and cytochrome bc1 complexes arising from the increased packing density as the intracytoplasmic membrane (ICM) bilayer becomes crowded with LH2 rings. In addition to downshifts in light intensity as a paradigm

  6. Characterization of purple and green photosynthetic bacteria isolated from the lagoon of Agatti Atoll (Lakshadweep Sea)

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; Chandramohan, D

    s wa s als o sup hyphenminus plemented wit h 0.5 g of sterile boile d egg pe r tub e t o test for photoorganotrophi c Rhodospirillaceae . At the end o f the incubatio n period , som e tube s develope d intense purpl e viole t colouratio n an d som e... s o f purpl e bacteria develope d bot h o n organi c an d inorgani c media. Th e developmen t was , however , faste r i n th e organic medium . Th e cells tende d t o gro w i n aggre hyphenminus gates o n th e walls o f the tubes . Microscopi c examin...

  7. Excitonic level structures of LH1 and LH2 of purple photosynthetic bacteria using an analytical approach

    Institute of Scientific and Technical Information of China (English)

    杨光参; 汪力; 杨国桢

    2003-01-01

    The excitonic level structure of a ring-like chain of dimers is discussed analytically in order to aid the understanding of the possible spectral properties of LH1 and LH2 of purple photosynthetic bacteria. Under the approximation of dipoledipole interaction between Bchls, the excitonic levels, bandwidths and energy gap between two Davydov subbands are expressed analytically in terms of interaction energies and configurational parameters of dipoles. Our model includes all the interactions between pigment molecules in the system. The oscillator strengths and circular dichroism (CD) for the excitonic states are also presented analytically. The simulated absorption and CD spectra of LH1 and LH2 complexes reproduce the main features of the measured results.

  8. Transient grating spectroscopy in photosynthetic purple bacteria Rhodobacter sphaeroides 2.4.1

    Energy Technology Data Exchange (ETDEWEB)

    Sugisaki, Mitsuru, E-mail: mitsuru@sci.osaka-cu.ac.j [CREST-JST and Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585 (Japan); Fujiwara, Masazumi; Fujii, Ritsuko [CREST-JST and Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585 (Japan); Nakagawa, Katsunori; Nango, Mamoru [CREST-JST and Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555 (Japan); Cogdell, Richard J. [Glasgow Biomedical Research Centre, IBLS, University of Glasgow, 126 University Place, Glasgow G12 8TA, Scotland (United Kingdom); Hashimoto, Hideki [CREST-JST and Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585 (Japan)

    2009-12-15

    The vibronic coherence of photosynthetic pigment-protein complexes has been investigated by means of transient grating spectroscopy using sub 20 fs optical pulses. In the present work, we focus our attention on the LH2 antenna complexes from Rhodobacter sphaeroides 2.4.1 because the information about their structure investigated by the electron and atomic force microscopy is available and the electric levels of pigments are well resolved, resulting in clear absorption spectrum. The vibronic coherent oscillations with a period of a few tens of femtoseconds have been clearly observed. We found that the temporal change of the coherent oscillations reflects the vibrational relaxation in the ground state. Calculations based on the Brownian oscillator model were performed under the impulsive excitation limit. The spectral density has been determined from the Raman measurement of spheroidene. Good agreement between the calculation and the experimental results has been achieved in the linear absorption spectrum and transient grating signal, which strongly supports the validity of our model.

  9. STUDY ON THE STRUCTURAL BASIS OF PERIPHERAL LIGHT HARVESTING COMPLEXES (LH2 IN PURPLE NON-SULPHUR PHOTOSYNTHETIC BACTERIA

    Directory of Open Access Journals (Sweden)

    Tatas H.P. Brotosudarmo

    2010-12-01

    Full Text Available Photosynthesis provides an example of a natural process that has been optimized during evolution to harness solar energy efficiently and safely, and finally to use it to produce a carbon-based fuel. Initially, solar energy is captured by the light harvesting pigment-protein complexes. In purple bacteria these antenna complexes are constructed on a rather simple modular basis. Light absorbed by these antenna complexes is funnelled downhill to reaction centres, where light drives a trans-membrane redox reaction. The light harvesting proteins not only provide the scaffolding that correctly positions the bacteriochlorophyll a and carotenoid pigments for optimal energy transfer but also creates an environment that can modulate the wavelength at which different bacteriochlorophyll molecules absorb light thereby creating the energy funnel. How these proteins can modulate the absorption spectra of the bacteriochlorophylls will be discussed in this review.

  10. Molecular Mechanism of Solar Energy Harvesting by Purple Photosynthetic Bacteria%紫色光合细菌捕获太阳能的分子机理

    Institute of Scientific and Technical Information of China (English)

    王万能; 陈国平; 胡宗利; 李尽哲; 何帅

    2011-01-01

    光合作用是地球上最重要的化学反应,生物体通过它捕获太阳能,转为化学能供生长繁殖需要.光合细菌是地球上最早出现的具有原始光能合成体系的微生物,其光合反应中心是一个由多种色素分子与蛋白质以非共价键方式结合的、具有特定构象的色素-蛋白复合体-光反应中心RC(Reaction center)和LH(Light Harvesting),光能通过电荷分离及电子转移反应转化为化学能,其效率是当前人工模拟远远不能及的.本文综述了紫色光合细菌捕获太阳能的分子结构、作用机理的研究进展,并结合作者在R.sphaeroides LHII蛋白组份同源及异源基因表达方面的研究结果进行相应的分析,明确了Rhodobacter sphaeroides基因组中同源基因puc2BA的表达特点和功能,Rhodovulum sulfidophilum pucsBA与R.sphaeroides pufBA能够同时在R.sphaeroides中表达,能同时形成LHII和LHI,并具有能量传递功能.%Photosynthesis is arguably the most important biological process, by it organisms harvest solar energy and transfer it into chemical energy for growth and reproduction.The photosynthetic bacteria are the earliest microbe with photosynthesis found on earth.The photosynthetic apparatus of purple bacteria is a nanometric assembly in the intracytoplasmic membranes and consists of pigment-protein complexes, the photosynthetic RC (Reaction center) and LH (Light harvesting).The primary processes of photosynthesis involve absorption of photons by LH complexes, transfer of excitation energy from the LH complexes to the photosynthetic RC, where the primary energy conversion takes place.The researches on molecular structure and mechanism of purple photosynthetic bacteria harvesting solar energy were summarized.Molecular biology techniques and spectroscopic analysis were applied to research the expression and function of puc2BA and pucsBA by the authors, and it was concluded that the puc2BA gene was normally expressed in Rhodobacter

  11. Genes involved in the biosynthesis of photosynthetic pigments in the purple sulfur photosynthetic bacterium Thiocapsa roseopersicina.

    Science.gov (United States)

    Kovács, Akos T; Rákhely, Gábor; Kovács, Kornél L

    2003-06-01

    A pigment mutant strain of the purple sulfur photosynthetic bacterium Thiocapsa roseopersicina BBS was isolated by plasposon mutagenesis. Nineteen open reading frame, most of which are thought to be genes involved in the biosynthesis of carotenoids, bacteriochlorophyll, and the photosynthetic reaction center, were identified surrounding the plasposon in a 22-kb-long chromosomal locus. The general arrangement of the photosynthetic genes was similar to that in other purple photosynthetic bacteria; however, the locations of a few genes occurring in this region were unusual. Most of the gene products showed the highest similarity to the corresponding proteins in Rubrivivax gelatinosus. The plasposon was inserted into the crtD gene, likely inactivating crtC as well, and the carotenoid composition of the mutant strain corresponded to the aborted spirilloxanthin pathway. Homologous and heterologous complementation experiments indicated a conserved function of CrtC and CrtD in the purple photosynthetic bacteria. The crtDC and crtE genes were shown to be regulated by oxygen, and a role of CrtJ in aerobic repression was suggested.

  12. Photoreceptor proteins from purple bacteria

    NARCIS (Netherlands)

    Hendriks, J.; van der Horst, M.A.; Chua, T.K.; Ávila Pérez, M.; van Wilderen, L.J.; Alexandre, M.T.A.; Groot, M.-L.; Kennis, J.T.M.; Hellingwerf, K.J.; Hunter, C.N.; Daldal, F.; Thurnauer, M.C.; Beatty, J.T.

    2009-01-01

    Purple bacteria contain representatives of four of the six main families of photoreceptor proteins: phytochromes, BLUF domain containing proteins, xanthopsins (i.e., photoactive yellow proteins), and phototropins (containing one or more light, oxygen, or voltage (LOV) domains). Most of them have a

  13. Rings, ellipses and horseshoes: how purple bacteria harvest solar energy.

    Science.gov (United States)

    Cogdell, Richard J; Gardiner, Alastair T; Roszak, Aleksander W; Law, Christopher J; Southall, June; Isaacs, Neil W

    2004-01-01

    This Review summarises the current state of research on the structure and function of light-harvesting apparatus in purple photosynthetic bacteria. Particular emphasis is placed on the major open questions still outstanding in this field in addition to what is already known.

  14. On the biphoton excitation of the fluorescence of the bacteriochlorophyll molecules of purple photosynthetic bacteria by powerful near IR femto-picosecond pulses

    Energy Technology Data Exchange (ETDEWEB)

    Borisov, A. Yu., E-mail: borissov@belozersky.msu.ru [Moscow State University, Belozersky Institute of Physicochemical Biology (Russian Federation)

    2011-11-15

    The authors of a number of experimental works detected nonresonance biphoton excitation of bacteriochlorophyll molecules, which represent the main pigment in the light-absorbing natural 'antenna' complexes of photosynthesizing purple bacteria, by femtosecond IR pulses (1250-1500 nm). They believe that IR quanta excite hypothetic forbidden levels of the pigments of these bacteria in the double frequency range 625-750 nm. We propose and ground an alternative triplet mechanism to describe this phenomenon. According to our hypothesis, the mechanism of biphoton excitation of molecules by IR quanta can manifest itself specifically, through high triplet levels of molecules in the high fields induced by femtosecond-picosecond laser pulses.

  15. Rhodopseudomonas acidophila strain 10050 contains photosynthetic LH2 antenna complexes that are not enriched with phosphatidylglycerol, and the phospholipids have a fatty acyl composition that is unusual for purple non-sulfur bacteria.

    Science.gov (United States)

    Russell, Nicholas J; Coleman, Julie K; Howard, Tina D; Johnston, Evelyn; Cogdell, Richard J

    2002-12-01

    The phospholipid composition of Rhodopseudomonas acidophila strain 10050 grown aerobically or anaerobically in the light was determined. The major phospholipids present in the aerobic cells were phosphatidylethanolamine (PE; 54%), phosphatidylglycerol (PG; 24%) and cardiolipin (diphosphatidylglycerol, DPG) (14%), together with phosphatidylcholine (PC; 5%). On moving the cells to anaerobic photosynthetic growth in the light PE remained the major phospholipid (37-49%), but there was a major change in the proportion of PC, which increased to 31-33%, and corresponding reductions in the contents of PG to 11-16% and DPG to 4-5%. The fatty acid composition of the phospholipids was unusual, compared with other purple non-sulfur photosynthetic bacteria, in that it contained 16:0 (29%), 17:1 (20%) and 19:1 (9%) plus several mainly unsaturated 2-OH fatty acids (9% total) as major components, when grown aerobically in the dark. In contrast when grown photosynthetically under anaerobic conditions there was <2% 17:1 or 19:1 present, while the amounts of 16:1 and 18:1 increased, and 16:0 decreased. The phospholipid composition of the purified light-harvesting complex 2 (LH2) complex was PE (43%), PC (42%) and DPG (15%). Unexpectedly, there was no PG associated with the purified LH2. These findings contrast with previous studies on several other photosynthetic bacteria, which had shown an increase in PG upon photosynthetic growth [Biochem. J. 181 (1979) 339]. The prior hypothesis that phosphatidylglycerol has some specific role to play in the function of light-harvesting complexes cannot be true for Rps. acidophila. It is suggested that specific integral membrane proteins may strongly influence the phospholipid content of the host membranes into which they are inserted.

  16. 3种紫细菌天然光合色素敏化DSSC光电转化性能%Photoelectric conversion performance of natural photosynthetic pigments from three typical members of purple bacteria for dye-sensitized solar cells

    Institute of Scientific and Technical Information of China (English)

    付乔明; 赵春贵; 杨素萍

    2014-01-01

    基于自然界光合作用机理的DSSC研究备受关注。不产氧光合细菌中的紫细菌是研究光合作用机理的良好模式生物。从3种典型紫细菌中获得了7种具有不同吸光范围、极性和结构的细菌叶绿素a(BChl a)和类胡萝卜素(Car)以及3种改性BChl a。在此基础上,较系统地比较了天然与改性BChl a、多组分与单一组分Car、BChl a色素浓度、BChl a和Car共敏对DSSC光电性能的影响,并对色素与半导体材料的相互作用进行了表征。结果表明:100 mW·cm-2入射光强下,在不添加任何分散剂(spacer)的条件下,具有近红外吸收的天然BChl a光电转化性能较优,光电转换效率为1.26%。单一组分Car比多组分Car具有较高的光电性能,玫红品Car光电转换效率最佳。BChl a敏化TiO2薄膜电极,吸收光谱红移,800 nm特征荧光淬灭。BChl a与Car共敏TiO2薄膜电极,拓宽了可见光吸收光谱,短路电流和光电转换效率比BChl a提高了12%和7.3%。紫细菌天然色素廉价易得、环境友好,不仅能吸收可见光,而且能有效利用红外光,这对研制响应可见光-近红外的太阳能电池光电器件具有重要参考价值。%The photovoltaic conversion systems based on photosynthesis have recently attracted much attention as alternative energy technology of the future. More interests are focused on the development of eco-friendly, cost-effective and safer dye-sensitized solar cells (DSSC)based on the principles and natural pigments of photosynthesis. Purple bacteria in anoxygenic phototrophic bacteria are good model systems for elucidating molecular mechanisms of photosynthesis. In this study, the photoelectrochemical properties of seven different natural photosynthetic pigments of bacteriochlorophyll a (BChl a) and carotenoids (Car) from Rhodopseudomonas palustris CQV97, Rhodobacter azotoformans R7 and Marichromatium sp. 283-1, and three modified BChl a

  17. Sun-beams, cucumbers, and purple bacteria : Historical milestones in early studies of photosynthesis revisited.

    Science.gov (United States)

    Gest, H

    1988-10-01

    Discovery of the general outlines of plant and bacterial photosyntheses required the efforts of a large number of gifted scientists over the course of two centuries. The first to suggest that sunlight might affect plants in some way other than through conversion of light to heat was Stephen Hales, in 1725, and this notion was promptly satirized by Jonathan Swift in his description of the "cucumber project" inGulliver's Travels (1726). Considerably later, in 1772, Joseph Priestley reported the first experiments showing the production of "dephlogisticated air" (oxygen gas) by plants, and the interdependence of animal and plant life mediated by gases. Priestley and others, however, had difficulty repeating these experiments, mainly because they were unaware of the requirement for light in photosynthesis. The latter was clearly demonstrated in 1779 by Jan Ingen-Housz, who also determined that leaves were the primary sites of the photosynthetic production of oxygen by plants. When purple bacteria were first studied in the late 19th century by Theodor Engelmann, light-dependent O2 formation could not be detected. Contradictory observations in this connection were reported for a number of decades, but eventually the absence of O2 production in photosynthesis by purple bacteria was conclusively established. Attempts to explain why the bacteria do not evolve O2 led Cornelis van Niel to propose a "unified, comparative biochemical" explanation of photosynthetic processes that was widely accepted. This hypothesis, however, was abandoned soon after photophosphorylation by membranes from purple bacteria and plant chloroplasts was discovered in 1954. Unexpectedly, rapid progress in molecular biological and genetic studies of the membrane-bound reaction centers of purple bacteria indicate that current investigations are on the verge of revealing the detailed mechanisms by which energy conversion occurs in the reaction centers of all photosynthetic organisms.

  18. Geometry, supertransfer, and optimality in the light harvesting of purple bacteria

    CERN Document Server

    Baghbanzadeh, Sima

    2016-01-01

    The remarkable rotational symmetry of the photosynthetic antenna complexes of purple bacteria has long been thought to enhance their light harvesting and excitation energy transport. We study the role of symmetry by modeling hypothetical antennas whose symmetry is broken by altering the orientations of the bacteriochlorophyll pigments. We find that in both LH2 and LH1 complexes, symmetry increases energy transfer rates by enabling the cooperative, coherent process of supertransfer. The enhancement is particularly pronounced in the LH1 complex, whose natural geometry outperforms the average randomized geometry by 5.5 standard deviations, one of the most significant increase due to coherent effects in any photosynthetic complex studied to date.

  19. Nobel lecture. The photosynthetic reaction centre from the purple bacterium Rhodopseudomonas viridis.

    OpenAIRE

    Deisenhofer, J.; Michel, H

    1989-01-01

    In our lectures we first describe the history and methods of membrane protein crystallization, before we show how the structure of the photosynthetic reaction centre from the purple bacterium Rhodopseudomonas viridis was solved. Then the structure of this membrane protein complex is correlated with its function as a light-driven electron pump across the photosynthetic membrane. Finally we draw conclusions on the structure of the photosystem II reaction centre from plants and discuss the aspec...

  20. Taxonomy of phototrophic green and purple bacteria: a review.

    Science.gov (United States)

    Pfennig, N; Trüper, H G

    1983-01-01

    The presently existing classification for the green and purple bacteria comprises physiological-ecological assemblages of phototrophic bacteria with anoxygenic photosynthesis. The taxonomic units of the different levels were based entirely on common phenotypic traits, including morphological, cytological, physiological and biochemical characteristics. Since degrees of resemblance form the basis of the grouping, this classification cannot reflect the genetic or evolutionary relatedness of these bacteria, neither among themselves nor with other bacteria. The advantage of the artificial system, however, is the use of features which can be established in most laboratories and which allow the comparison and identification of newly isolated strains with those already studied and described. The four existing families correspond to the four major recognized, ecophysiological groups, the Chlorobiaceae and Chloroflexaceae among the green bacteria, and the Chromatiaceae and Rhodospirillaceae among the purple bacteria. Our knowledge of all these groups is incomplete; this is reflected by the fact that seven new species have been described during the past three years (6th Newsletter on phot. bacteria, Trüper and Hansen, 1982). The description of the new genus and species Erythrobacter longus (Shiba and Simidu, 1982) is also interesting, as it comprises aerobic chemoorganotrophic marine bacteria which form bacteriochlorophyll a and carotenoids; however, no strains were able to grow phototrophilcally. Significant success is currently being obtained in the different approaches toward elucidating the genetic relationships within and outside of the purple and green bacteria. Detailed studies of the lipopolysaccharides of several species and genera of the Rhodospirillaceae (Weckesser et al., 1979, and more recent paper) have proven to be very useful for the recognition of relationships or dissimilarities between the species of a genus or between different genera. Amino acid sequence

  1. The Photosynthetic Reaction Center from the Purple Bacterium Rhodopseudomonas viridis

    Science.gov (United States)

    Deisenhofer, Johann; Michel, Hartmut

    1989-09-01

    The history and methods of membrane protein crystallization are described. The solution of the structure of the photosynthetic reaction center from the bacterium Rhodopseudomonas viridis is described, and the structure of this membrane protein complex is correlated with its function as a light-driven electron pump across the photosynthetic membrane. Conclusions about the structure of the photosystem II reaction center from plants are drawn, and aspects of membrane protein structure are discussed.

  2. The structural basis of light-harvesting in purple bacteria.

    Science.gov (United States)

    Cogdell, Richard J; Isaacs, Neil W; Freer, Andrew A; Howard, Tina D; Gardiner, Alastair T; Prince, Steve M; Papiz, Miroslavr Z

    2003-11-27

    A typical purple bacterial photosynthetic unit consists of two types of light-harvesting complex (LH1 and LH2) together with a reaction centre. This short review presents a description of the structure of the LH2 complex from Rhodopseudomonas acidophila, which has recently been improved to a resolution of 2.0 A [Papiz et al., J. Mol. Biol. 326 (2003) 1523-1538]. We show how this structure has helped to reveal the details of the various excitation energy transfer events in which it is involved.

  3. Spectroscopic studies of two spectral variants of light-harvesting complex 2 (LH2) from the photosynthetic purple sulfur bacterium Allochromatium vinosum

    National Research Council Canada - National Science Library

    Niedzwiedzki, Dariusz M; Bina, David; Picken, Nichola; Honkanen, Suvi; Blankenship, Robert E; Holten, Dewey; Cogdell, Richard J

    2012-01-01

    Two spectral forms of the peripheral light-harvesting complex (LH2) from the purple sulfur photosynthetic bacterium Allochromatium vinosum were purified and their photophysical properties characterized...

  4. Origin of mitochondria by intracellular enslavement of a photosynthetic purple bacterium

    OpenAIRE

    CAVALIER-SMITH, THOMAS

    2006-01-01

    Mitochondria originated by permanent enslavement of purple non-sulphur bacteria. These endosymbionts became organelles through the origin of complex protein-import machinery and insertion into their inner membranes of protein carriers for extracting energy for the host. A chicken-and-egg problem exists: selective advantages for evolving import machinery were absent until inner membrane carriers were present, but this very machinery is now required for carrier insertion. I argue here that this...

  5. Biosynthesis and Isotopic Composition of Bacteriochlorophyll a and Okenone in Purple Sulfur Bacteria

    Science.gov (United States)

    Smith, D.; Scott, J. H.; Steele, A.; Cody, G. D.; Ohara, S.; Bowden, R.; Fogel, M. L.

    2011-12-01

    Phototrophic sulfur bacteria play an integral part in the anaerobic cycling of sulfur. Bacteriochloroyphll a (Bchl a) is a well-studied photosynthetic compound required for photosynthesis in the organisms that possess it. The only known fossil of purple sulfur bacteria (PSB) in the geologic record is okenane, believed to be of biologic origin originating from the carotenoid pigment okenone, which has only been documented in eleven species of Chromatiaceae. Organic geochemical studies have identified okenane in preserved organic matter in rocks and ancient sediments and further, okenone production has been observed in modern water columns and sediment surfaces. We have undertaken a comprehensive study on the biosynthesis of bacterial pigments including okenone and C, N, and S isotopic fractionation during various growth modes in controlled laboratory experiments of purple sulfur bacteria. Cultures of Marichromatium purpuratum 1591, M. purpuratum 1711, Thiocapsa marina 5653, and FGL21 (isolated from the chemocline of Fayetteville Green Lake, NY) were grown under autotrophic and photoheterotrophic (e.g. acetate or pyruvate) conditions in batch cultures. Concentrations of okenone and Bchl a were quantified as a function of time and growth by Ultra Performance-Liquid Chromatography-Mass Spectrometry (UP-LC-MS) and spectrophotometry. Overall okenone and Bchl a concentrations reached μM levels in the cultures. At stationary phase, all four strains achieved concentrations of okenone and Bchl a that were approximately 2.5 fM and 0.2 fM per cell, respectively, with okenone to Bchl a ratios of approximately 12 to 1. Isotope Ratio Mass Spectrometry (IRMS) was performed on bulk cells and compound specific analysis of Bchl a and okenone to better understand the fractionation associated with the production of the compounds.

  6. Antenna organization in green photosynthetic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Blankenship, R.E.

    1987-01-01

    This project is concerned with the structure and function of the unique antenna system found in the green photosynthetic bacteria. The antenna system in these organisms is contained within a vesicle known as a chlorosome, which is attached to the cytoplasmic side of the cell membrane. Additional antenna pigments and reaction centers are contained in integral membrane proteins. Energy absorbed by the bacteriochlorophyll c (BChl c) pigments in the chlorosome is transferred via a baseplate'' array of BChl a antenna pigments into the membrane and to the reaction center. A schematic model of chlorosome structure is shown. This project is aimed at increasing our understanding of the organization of the pigments in the chlorosome and how the antenna system functions.

  7. Excitonic energy transfer in light-harvesting complexes in purple bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Ye Jun; Sun Kewei; Zhao Yang; Lee, Chee Kong [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Yu Yunjin [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); College of Physics Science and Technology, Shenzhen University, Guangdong 518060 (China); Cao Jianshu [Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2012-06-28

    Two distinct approaches, the Frenkel-Dirac time-dependent variation and the Haken-Strobl model, are adopted to study energy transfer dynamics in single-ring and double-ring light-harvesting (LH) systems in purple bacteria. It is found that the inclusion of long-range dipolar interactions in the two methods results in significant increase in intra- or inter-ring exciton transfer efficiency. The dependence of exciton transfer efficiency on trapping positions on single rings of LH2 (B850) and LH1 is similar to that in toy models with nearest-neighbor coupling only. However, owing to the symmetry breaking caused by the dimerization of BChls and dipolar couplings, such dependence has been largely suppressed. In the studies of coupled-ring systems, both methods reveal an interesting role of dipolar interactions in increasing energy transfer efficiency by introducing multiple intra/inter-ring transfer paths. Importantly, the time scale (4 ps) of inter-ring exciton transfer obtained from polaron dynamics is in good agreement with previous studies. In a double-ring LH2 system, non-nearest neighbor interactions can induce symmetry breaking, which leads to global and local minima of the average trapping time in the presence of a non-zero dephasing rate, suggesting that environment dephasing helps preserve quantum coherent energy transfer when the perfect circular symmetry in the hypothetic system is broken. This study reveals that dipolar coupling between chromophores may play an important role in the high energy transfer efficiency in the LH systems of purple bacteria and many other natural photosynthetic systems.

  8. The architecture and function of the light-harvesting apparatus of purple bacteria: from single molecules to in vivo membranes.

    Science.gov (United States)

    Cogdell, Richard J; Gall, Andrew; Köhler, Jürgen

    2006-08-01

    This review describes the structures of the two major integral membrane pigment complexes, the RC-LH1 'core' and LH2 complexes, which together make up the light-harvesting system present in typical purple photosynthetic bacteria. The antenna complexes serve to absorb incident solar radiation and to transfer it to the reaction centres, where it is used to 'power' the photosynthetic redox reaction and ultimately leads to the synthesis of ATP. Our current understanding of the biosynthesis and assembly of the LH and RC complexes is described, with special emphasis on the roles of the newly described bacteriophytochromes. Using both the structural information and that obtained from a wide variety of biophysical techniques, the details of each of the different energy-transfer reactions that occur, between the absorption of a photon and the charge separation in the RC, are described. Special emphasis is given to show how the use of single-molecule spectroscopy has provided a more detailed understanding of the molecular mechanisms involved in the energy-transfer processes. We have tried, with the help of an Appendix, to make the details of the quantum mechanics that are required to appreciate these molecular mechanisms, accessible to mathematically illiterate biologists. The elegance of the purple bacterial light-harvesting system lies in the way in which it has cleverly exploited quantum mechanics.

  9. Dimeric carotenoid interaction in the light-harvesting antenna of purple phototrophic bacteria.

    Science.gov (United States)

    Zurdo, J; Lozano, R M; Fernandez-Cabrera, C; Ramirez, J M

    1991-03-15

    The carotenoid content of intracytoplasmic membrane vesicles isolated from purple phototrophic bacteria was reduced to a variable extent by mild extraction with light petroleum. Using preparations obtained from Rhodobacter capsulatus strains that contained the Light Harvesting System I (LHI) complex as the only major photosynthetic holochrome, it was shown that the visible circular dichroism of the carotenoids increased with the square of the membrane carotenoid content, as expected from being caused by dimeric exciton interaction. No chirality resulting from twists of the individual planar chromophore was detected. Therefore the contribution to carotenoid optical activity of non-degenerate interactions with bacteriochlorophyll or the apoprotein does not appear to be significant. The broadening of the absorption band of the bound pigment, caused by the splitting of the monomer transition, was demonstrated in membrane vesicles of both Rb, capsulatus and Rhodospirillum rubrum as a decrease of the fine structure of the band. Furthermore, the dimeric organization of the carotenoid pigments in the bacterial LHI complex accounted for the observed quantitative relationship between the fine structure of the band and the carotenoid content of the membrane.

  10. Characterisation of the LH2 spectral variants produced by the photosynthetic purple sulphur bacterium Allochromatium vinosum.

    Science.gov (United States)

    Carey, Anne-Marie; Hacking, Kirsty; Picken, Nichola; Honkanen, Suvi; Kelly, Sharon; Niedzwiedzki, Dariusz M; Blankenship, Robert E; Shimizu, Yuuki; Wang-Otomo, Zheng-Yu; Cogdell, Richard J

    2014-11-01

    This study systematically investigated the different types of LH2 produced by Allochromatium (Alc.) vinosum, a photosynthetic purple sulphur bacterium, in response to variations in growth conditions. Three different spectral forms of LH2 were isolated and purified, the B800-820, B800-840 and B800-850 LH2 types, all of which exhibit an unusual split 800 peak in their low temperature absorption spectra. However, it is likely that more forms are also present. Relatively more B800-820 and B800-840 are produced under low light conditions, while relatively more B800-850 is produced under high light conditions. Polypeptide compositions of the three different LH2 types were determined by a combination of HPLC and TOF/MS. The B800-820, B800-840 and B800-850 LH2 types all have a heterogeneous polypeptide composition, containing multiple types of both α and β polypeptides, and differ in their precise polypeptide composition. They all have a mixed carotenoid composition, containing carotenoids of the spirilloxanthin series. In all cases the most abundant carotenoid is rhodopin; however, there is a shift towards carotenoids with a higher conjugation number in LH2 complexes produced under low light conditions. CD spectroscopy, together with the polypeptide analysis, demonstrates that these Alc. vinosum LH2 complexes are more closely related to the LH2 complex from Phs. molischianum than they are to the LH2 complexes from Rps. acidophila.

  11. Comprehensive Analysis of Photosynthetic Characteristics and Quality Improvement of Purple Cabbage under Different Combinations of Monochromatic Light

    Science.gov (United States)

    Yang, Biyun; Zhou, Xiangzhu; Xu, Ru; Wang, Jin; Lin, Yizhang; Pang, Jie; Wu, Shuang; Zhong, Fenglin

    2016-01-01

    Light is essential for plant growth. Light intensity, photoperiod, and light quality all affect plant morphology and physiology. Compared to light intensity, photoperiod, little is known about the effects of different monochromatic lights on crop species. To investigate how different lighting conditions influence crops with heterogeneous colors in leaves, we examined photosynthetic characteristics and quality (regarding edibility and nutrition) of purple cabbage under different combinations of lights. Eight different treatments were applied including monochromic red (R), monochromic blue (B), monochromic yellow (Y), monochromic green (G), and the combination of red and blue (3/1, RB), red/blue/yellow (3/1/1, RBY), red/blue/green (3/1/1,RBG), and white light as the control. Our results indicate that RBY (3/1/1) treatment promotes the PSII activity of purple cabbage, resulting in improved light energy utilization. By contrast, both G and Y lights alone have inhibitory effect on the PSII activity of purple cabbage. In addition, RBY (3/1/1) significantly boosts the anthocyanin and flavonoids content compared with other treatments. Although we detected highest soluble protein and vitamin C content under B treatment (increased by 30.0 and 14.3% compared with the control, respectively), RBY (3/1/1) appeared to be the second-best lighting condition (with soluble protein and vitamin C content increased by 8.6 and 4.1%, respectively compared with the control). Thus we prove that the addition of yellow light to the traditional combination of red/blue lighting conditions is beneficial to synthesizing photosynthetic pigments and enables superior outcome of purple cabbage growth. Our results indicate that the growth and nutritional quality of purple cabbage are greatly enhanced under RBY (3/1/1) light, and suggest that strategical management of lighting conditions holds promise in maximizing the economic efficiency of plant production and food quality of vegetables grown in

  12. Treatment of Chinese Traditional Medicine Wastewater by Photosynthetic Bacteria

    Institute of Scientific and Technical Information of China (English)

    WANG You-zhi; WANG Feng-jun; BAO Li

    2005-01-01

    The influence factors treating wastewater of Chinese traditional medicine extraction by photosynthetic bacteria are tested and discussed. The results indicate that the method of photosynthetic bacteria can eliminate COD and BCD from wastewater in high efficiency. And it also has high load shock resistance. On the conditions of slight aerobic and semi-darkness, treating wastewater of Chinese traditional medicine extraction, the method has better efficiency to eliminate COD and BOD from the wastewater than those by anaerobic illumination and aerobic darkness treatments. After pretreatment of hydrolytic acidization, the removal rate of COD in the wastewater reached more than 85 %, and that rate of BOD reached more than 90% in the treating system of photosynthetic bacteria. It may be more feasible and advantageous than traditional anaerobic biological process to treat organic wastewater using PSB system.

  13. Origin of mitochondria by intracellular enslavement of a photosynthetic purple bacterium.

    Science.gov (United States)

    Cavalier-Smith, Thomas

    2006-08-07

    Mitochondria originated by permanent enslavement of purple non-sulphur bacteria. These endosymbionts became organelles through the origin of complex protein-import machinery and insertion into their inner membranes of protein carriers for extracting energy for the host. A chicken-and-egg problem exists: selective advantages for evolving import machinery were absent until inner membrane carriers were present, but this very machinery is now required for carrier insertion. I argue here that this problem was probably circumvented by conversion of the symbiont protein-export machinery into protein-import machinery, in three phases. I suggest that the first carrier entered the periplasmic space via pre-existing beta-barrel proteins in the bacterial outer membrane that later became Tom40, and inserted into the inner membrane probably helped by a pre-existing inner membrane protein, thereby immediately providing the protoeukaryote host with photosynthesate. This would have created a powerful selective advantage for evolving more efficient carrier import by inserting Tom70 receptors. Massive gene transfer to the nucleus inevitably occurred by mutation pressure. Finally, pressure from harmful, non-selected gene transfer to the nucleus probably caused evolution of the presequence mechanism, and photosynthesis was lost.

  14. 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.

  15. 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.

  16. On the role of cytochrome c8 in photosynthetic electron transfer of the purple non-sulfur bacterium Rhodoferax fermentans

    DEFF Research Database (Denmark)

    Hochkoeppler, Alejandro; Ciurli, Stefano; Kofod, Pauli

    1997-01-01

    We report on the isolation, purification and functional characterization of a soluble c-type cytochrome from light-grown cells of the purple phototroph Rhodoferax fermentans. This cytochrome is basic (pI = 8), has a molecular mass of 12 kDa, and is characterized by a midpoint reduction potential...... of +285 mV. Partial analysis of the N-terminus amino-acid sequence shows a high similarity with cytochromes of c8 type (formerly called Pseudomonas cytochrome c-551 type). Time-resolved spectrophotometric studies show that this cytochrome c8 reduces the tetraheme subunit of the photosynthetic reaction...

  17. MATHEMATICAL SIMULATION OF THE INTERACTIONS AMONG CYANOBACTERIA, PURPLE SULFUR BACTERIA AND CHEMOTROPIC SULFUR BACTERIA IN MICROBIAL MAT COMMUNITIES

    NARCIS (Netherlands)

    DEWIT, R; VANDENENDE, FP; VANGEMERDEN, H

    1995-01-01

    A deterministic one-dimensional reaction diffusion model was constructed to simulate benthic stratification patterns and population dynamics of cyanobacteria, purple and colorless sulfur bacteria as found in marine microbial mats. The model involves the major biogeochemical processes of the sulfur c

  18. MATHEMATICAL SIMULATION OF THE INTERACTIONS AMONG CYANOBACTERIA, PURPLE SULFUR BACTERIA AND CHEMOTROPIC SULFUR BACTERIA IN MICROBIAL MAT COMMUNITIES

    NARCIS (Netherlands)

    DEWIT, R; VANDENENDE, FP; VANGEMERDEN, H

    1995-01-01

    A deterministic one-dimensional reaction diffusion model was constructed to simulate benthic stratification patterns and population dynamics of cyanobacteria, purple and colorless sulfur bacteria as found in marine microbial mats. The model involves the major biogeochemical processes of the sulfur c

  19. MATHEMATICAL SIMULATION OF THE INTERACTIONS AMONG CYANOBACTERIA, PURPLE SULFUR BACTERIA AND CHEMOTROPIC SULFUR BACTERIA IN MICROBIAL MAT COMMUNITIES

    NARCIS (Netherlands)

    DEWIT, R; VANDENENDE, FP; VANGEMERDEN, H

    A deterministic one-dimensional reaction diffusion model was constructed to simulate benthic stratification patterns and population dynamics of cyanobacteria, purple and colorless sulfur bacteria as found in marine microbial mats. The model involves the major biogeochemical processes of the sulfur

  20. Studies on photosynthetic bacteria isolated from an estuarine beach of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Karanth, N.G.K.; Nair, S.; LokaBharathi, P.A.

    -sulphur purple bacteria). It had a characteristic absorption maximum at 850 nm which is a general feature of purple bacteria. The optimum pH for this strain was 7. Effect of different organic substances, nitrogenous compounds, and pollutants CO2 fixation...

  1. 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) 4....... sphaeroides was around 35% of dry cell weight, mainly composed of vaccenic acid (C18:1, omega-7)....

  2. Metabolic network modeling of redox balancing and biohydrogen production in purple nonsulfur bacteria

    Directory of Open Access Journals (Sweden)

    Grammel Hartmut

    2011-09-01

    Full Text Available Abstract Background Purple nonsulfur bacteria (PNSB are facultative photosynthetic bacteria and exhibit an extremely versatile metabolism. A central focus of research on PNSB dealt with the elucidation of mechanisms by which they manage to balance cellular redox under diverse conditions, in particular under photoheterotrophic growth. Results Given the complexity of the central metabolism of PNSB, metabolic modeling becomes crucial for an integrated analysis of the accumulated biological knowledge. We reconstructed a stoichiometric model capturing the central metabolism of three important representatives of PNSB (Rhodospirillum rubrum, Rhodobacter sphaeroides and Rhodopseudomonas palustris. Using flux variability analysis, the model reveals key metabolic constraints related to redox homeostasis in these bacteria. With the help of the model we can (i give quantitative explanations for non-intuitive, partially species-specific phenomena of photoheterotrophic growth of PNSB, (ii reproduce various quantitative experimental data, and (iii formulate several new hypotheses. For example, model analysis of photoheterotrophic growth reveals that - despite a large number of utilizable catabolic pathways - substrate-specific biomass and CO2 yields are fixed constraints, irrespective of the assumption of optimal growth. Furthermore, our model explains quantitatively why a CO2 fixing pathway such as the Calvin cycle is required by PNSB for many substrates (even if CO2 is released. We also analyze the role of other pathways potentially involved in redox metabolism and how they affect quantitatively the required capacity of the Calvin cycle. Our model also enables us to discriminate between different acetate assimilation pathways that were proposed recently for R. sphaeroides and R. rubrum, both lacking the isocitrate lyase. Finally, we demonstrate the value of the metabolic model also for potential biotechnological applications: we examine the theoretical

  3. Photosynthetic bacteria as alternative energy sources: overview on hydrogen production research

    Energy Technology Data Exchange (ETDEWEB)

    Mitsui, A.; Ohta, Y.; Frank, J.

    1979-01-01

    Hydrogen production research towards the application of marine and non-marine species of photosynthetic bacteria is reviewed. Potential use of photosynthetic bacteria as renewable energy resources is discussed.

  4. Characteristics of purple nonsulfur bacteria grown under Stevia residue extractions.

    Science.gov (United States)

    Xu, J; Feng, Y; Wang, Y; Lin, X

    2013-11-01

    As a consequence of the large-scale cultivation of Stevia plants, releases of plant residues, the byproduct after sweetener extraction, to the environment are inevitable. Stevia residue and its effluent after batching up contain large amounts of organic matters with small molecular weight, which therefore are a potential pollution source. Meanwhile, they are favourite substrates for micro-organism growths. This investigation was aimed to utilize the simulated effluent of Stevia residue to enrich the representative purple nonsulfur bacterium (PNSB), Rhodopseudomonas palustris (Rps. palustris), which has important economic values. The growth profile and quality of Rps. palustris were characterized by spectrophotometry, compared to those grown in common PNSB mineral synthetic medium. Our results revealed that the simulated effluent of Stevia residue not only stimulated Rps. palustris growth to a greater extent, but also increased its physiologically active cytochrome concentrations and excreted indole-3-acetic acid (IAA) content. This variation in phenotype of Rps. palustris could result from the shift in its genotype, further revealed by the repetitive sequence-based PCR (rep-PCR) fingerprinting analysis. Our results showed that the effluent of Stevia residue was a promising substrate for microbial growth.

  5. Stoichiometry and kinetics of mercury uptake by photosynthetic bacteria.

    Science.gov (United States)

    Kis, Mariann; Sipka, Gábor; Maróti, Péter

    2017-05-01

    Mercury adsorption on the cell surface and intracellular uptake by bacteria represent the key first step in the production and accumulation of highly toxic mercury in living organisms. In this work, the biophysical characteristics of mercury bioaccumulation are studied in intact cells of photosynthetic bacteria by use of analytical (dithizone) assay and physiological photosynthetic markers (pigment content, fluorescence induction, and membrane potential) to determine the amount of mercury ions bound to the cell surface and taken up by the cell. It is shown that the Hg(II) uptake mechanism (1) has two kinetically distinguishable components, (2) includes co-opted influx through heavy metal transporters since the slow component is inhibited by Ca(2+) channel blockers, (3) shows complex pH dependence demonstrating the competition of ligand binding of Hg(II) ions with H(+) ions (low pH) and high tendency of complex formation of Hg(II) with hydroxyl ions (high pH), and (4) is not a passive but an energy-dependent process as evidenced by light activation and inhibition by protonophore. Photosynthetic bacteria can accumulate Hg(II) in amounts much (about 10(5)) greater than their own masses by well-defined strong and weak binding sites with equilibrium binding constants in the range of 1 (μM)(-1) and 1 (mM)(-1), respectively. The strong binding sites are attributed to sulfhydryl groups as the uptake is blocked by use of sulfhydryl modifying agents and their number is much (two orders of magnitude) smaller than the number of weak binding sites. Biofilms developed by some bacteria (e.g., Rvx. gelatinosus) increase the mercury binding capacity further by a factor of about five. Photosynthetic bacteria in the light act as a sponge of Hg(II) and can be potentially used for biomonitoring and bioremediation of mercury-contaminated aqueous cultures.

  6. Malate dehydrogenase in phototrophic purple bacteria: purification, molecular weight, and quaternary structure.

    OpenAIRE

    1987-01-01

    The citric acid cycle enzyme malate dehydrogenase was purified to homogeneity from the nonsulfur purple bacteria Rhodobacter capsulatus, Rhodospirillum rubrum, Rhodomicrobium vannielii, and Rhodocyclus purpureus. Malate dehydrogenase was purified from each species by either a single- or a two-step protocol: triazine dye affinity chromatography was the key step in purification of malate dehydrogenase in all cases. Purification of malate dehydrogenase resulted in a 130- to 240-fold increase in ...

  7. Temperature-induced dissociation reaction and dynamics of light-harvesting complex Ⅱ isolated from purple photosynthetic bacterium Rps. palustris

    Institute of Scientific and Technical Information of China (English)

    FENG Juan; LI XueFeng; LIU Yuan

    2007-01-01

    Steady-state absorption spectroscopy, circular dichroism, and resonance Raman spectroscopy have been used to investigate the thermal stability of LH2 complex isolated from purple photosynthetic bacterium Rps. Palustris. The results show that: 1) upon increasing the temperature, a transition from B800 and B850 to free bacteriochlorophyll (B780) happens; 2) a gradual decrease and disappearance of CD signal in visible region occur; 3) a shift of the frequency, belonging to C=C and C-C stretching vibration, to higher wavenumber takes place. It is suggested that LH2 complex can be dissociated in the presence of B800, B850 and carotenoids simultaneously. Single-exponential fitting on the dynamic decay curves gives the apparent time constants of hundreds of minutes for various pigments.

  8. Continuous Cultivation of Photosynthetic Bacteria for Fatty Acids Production

    OpenAIRE

    Kim, Dong-Hoon; Lee, Ji-Hye; Hwang, Yuhoon; Kang, Seoktae; Kim, Mi-Sun

    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) 4 d, cell concentration continuously increased from 0.97 g dcw/L to 2.05 g dcw/L as lactate concentration increased from 30 mM to 60 mM. At 70 mM, however, cell concentration fluctuated with incomple...

  9. 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.

  10. Improved hydrogen photoproduction from photosynthetic bacteria and green algae

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, P.F.; Lien, S.; Seibert, M.

    1979-01-01

    Photosynthetic bacteria evolve hydrogen at much higher rates than do other classes of photosynthetic microorganisms. In addition, they tolerate harsh environments, grow rapidly, and utilize both visible and near infrared light in photosynthesis. They do not split water, but this does not necessarily eliminate their potential use in future applied systems. They are easily manipulated genetically, and thus might be modified to metabolize common biomass waste materials in place of expensive defined organic substrates. Furthermore, the potential for increasing hydrogen photoproduction via genetic techniques is promising. Strains that partially degrade cellulose, have high photoproduction rates, or contain very large amounts of the enzymes associated with hydrogen metabolism have been isolated. Green algae also produce hydrogen but are capable of using water as a substrate. For example, C. reinhardi can evolve hydrogen and oxygen at a molar ratio approaching 2:1. Based upon effect of dichlorophenyl dimethylurea (a specific inhibitor of photosystem II, PSII) on hydrogen photoproduction in the wild type strain and upon results obtained with PSII mutants, one can demonstrate that water is the major source of electrons for hydrogen production. The potential efficiency of in vivo coupling between hydrogenase and the photosynthetic electron transport system is high. Up to 76% of the reductants generated by the electron transport system can be channeled directly to the enzyme for in vivo hydrogen production. Rates exceeding 170 ..mu..moles of H/sub 2/ mg Chl/sup -1/ hr/sup -1/ have been observed.

  11. Evolutionary Competition Between Primitive Photosynthetic Systems: Existence of an early purple Earth?

    Science.gov (United States)

    Sparks, William B.; DasSarma, S.; Reid, I. N.

    2006-12-01

    The onset of photosynthesis in primitive cyanobacteria is thought to have profoundly altered the Earth’s atmosphere by producing an oxygen-rich atmosphere some 2 billion years ago. However, the pigments used by chlorophyll-based photosynthesis absorb at a variety of wavelengths, curiously except those centered around the peak of the Solar spectrum, 550nm. By contrast, simpler retinal-based light harvesting systems such as the haloarchaeal purple membrane bacteriorhodopsin and halorhodopsin show a strong well-defined peak of absorbance centered at 550nm. The spectroscopic complementarity for retinal pigments with chlorophyll-based pigments suggests an intriguing possibility of their co-evolution. This hypothesis argues that simpler retinal-based phototrophic capability may have evolved earlier, in microorganisms that dominated during the anaerobic and purple phase of the planet. Later, the more complex chlorophyll-based photosystem pigments could have evolved to harvest light in regions of the spectrum not absorbed by preexisting species. This would have led to the greening and oxidation of our planet and displacement of most of the retinal-based microorganisms. Not surprisingly, evidence for retinal chromoproteins have recently turned up in a variety of planktonic microorganisms. Although speculative, such a scenario would indicate that retinal-based phototrophy may be one of the oldest metabolic capabilities on Earth. Moreover, if the chlorophyll absorption spectrum is simply a product of adaptation, then its utility as a potential biomarker is likely to be limited.

  12. Metabolic Engineering and Modeling of Metabolic Pathways to Improve Hydrogen Production by Photosynthetic Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Y. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Navid, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-12-19

    Rising energy demands and the imperative to reduce carbon dioxide (CO2) emissions are driving research on biofuels development. Hydrogen gas (H2) is one of the most promising biofuels and is seen as a future energy carrier by virtue of the fact that 1) it is renewable, 2) does not evolve the “greenhouse gas” CO2 in combustion, 3) liberates large amounts of energy per unit weight in combustion (having about 3 times the energy content of gasoline), and 4) is easily converted to electricity by fuel cells. Among the various bioenergy strategies, environmental groups and others say that the concept of the direct manufacture of alternative fuels, such as H2, by photosynthetic organisms is the only biofuel alternative without significant negative criticism [1]. Biological H2 production by photosynthetic microorganisms requires the use of a simple solar reactor such as a transparent closed box, with low energy requirements, and is considered as an attractive system to develop as a biocatalyst for H2 production [2]. Various purple bacteria including Rhodopseudomonas palustris, can utilize organic substrates as electron donors to produce H2 at the expense of solar energy. Because of the elimination of energy cost used for H2O oxidation and the prevention of the production of O2 that inhibits the H2-producing enzymes, the efficiency of light energy conversion to H2 by anoxygenic photosynthetic bacteria is in principle much higher than that by green algae or cyanobacteria, and is regarded as one of the most promising cultures for biological H2 production [3]. Here implemented a simple and relatively straightforward strategy for hydrogen production by photosynthetic microorganisms using sunlight, sulfur- or iron-based inorganic substrates, and CO2 as the feedstock. Carefully selected microorganisms with bioengineered beneficial

  13. Photoprotection Mechanism of Light-Harvesting Antenna Complex from Purple Bacteria.

    Science.gov (United States)

    Kosumi, Daisuke; Horibe, Tomoko; Sugisaki, Mitsuru; Cogdell, Richard J; Hashimoto, Hideki

    2016-02-11

    Photosynthetic light-harvesting apparatus efficiently capture sunlight and transfer the energy to reaction centers, while they safely dissipate excess energy to surrounding environments for a protection of their organisms. In this study, we performed pump-probe spectroscopic measurements with a temporal window ranging from femtosecond to submillisecond on the purple bacterial antenna complex LH2 from Rhodobacter sphaeroides 2.4.1 to clarify its photoprotection functions. The observed excited state dynamics in the time range from subnanosecond to microsecond exhibits that the triplet-triplet excitation energy transfer from bacteriochlorophyll a to carotenoid takes place with a time constant of 16.7 ns. Furthermore, ultrafast spectroscopic data suggests that a molecular assembly of bacteriochlorophyll a in LH2 efficiently suppresses a generation of triple bacteriochlorophyll a.

  14. Fluorescence enhancement of light-harvesting complex 2 from purple bacteria coupled to spherical gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bujak, Ł. [Nicolaus Copernicus Univ., Torun (Poland). Inst. of Physics; Czechowski, N. [Nicolaus Copernicus Univ., Torun (Poland). Inst. of Physics; Piatkowski, D. [Nicolaus Copernicus Univ., Torun (Poland). Inst. of Physics; Litvin, R. [Nicolaus Copernicus Univ., Torun (Poland). Inst. of Physics; Mackowski, S. [Nicolaus Copernicus Univ., Torun (Poland). Inst. of Physics; Brotosudarmo, T. H. P. [Ma Chung Univ., Malang (Indonesia). Ma Chung Research Center for Photosynthetic Pigments; Pichler, S. [Univ. of Glasgow, Scotland (United Kingdom). Inst. of Molecular, Cell and Systems Biology; Cogdell, R. J. [Univ. Linz (Austria). Inst. fur Halbleiter-und Festkorperphysik; Heiss, W. [Univ. Linz (Austria). Inst. fur Halbleiter-und Festkorperphysik

    2011-10-24

    The influence of plasmon excitations in spherical gold nanoparticles on the optical properties of a light-harvesting complex 2 (LH2) from the purple bacteria Rhodopseudomonas palustris has been studied. Systematic analysis is facilitated by controlling the thickness of a silica layer between Au nanoparticles and LH2 complexes. Fluorescence of LH2 complexes features substantial increase when these complexes are separated by 12 nm from the gold nanoparticles. At shorter distances, non-radiative quenching leads to a decrease of fluorescence emission. The enhancement of fluorescence originates predominantly from an increase of absorption of pigments comprising the LH2 complex.

  15. Broadband 2D electronic spectroscopy reveals a carotenoid dark state in purple bacteria.

    Science.gov (United States)

    Ostroumov, Evgeny E; Mulvaney, Rachel M; Cogdell, Richard J; Scholes, Gregory D

    2013-04-01

    Although the energy transfer processes in natural light-harvesting systems have been intensively studied for the past 60 years, certain details of the underlying mechanisms remain controversial. We performed broadband two-dimensional (2D) electronic spectroscopy measurements on light-harvesting proteins from purple bacteria and isolated carotenoids in order to characterize in more detail the excited-state manifold of carotenoids, which channel energy to bacteriochlorophyll molecules. The data revealed a well-resolved signal consistent with a previously postulated carotenoid dark state, the presence of which was confirmed by global kinetic analysis. The results point to this state's role in mediating energy flow from carotenoid to bacteriochlorophyll.

  16. Protein structure, electron transfer and evolution of prokaryotic photosynthetic reaction centers

    Science.gov (United States)

    Blankenship, R. E.

    1994-01-01

    Photosynthetic reaction centers from a variety of organisms have been isolated and characterized. The groups of prokaryotic photosynthetic organisms include the purple bacteria, the filamentous green bacteria, the green sulfur bacteria and the heliobacteria as anoxygenic representatives as well as the cyanobacteria and prochlorophytes as oxygenic representatives. This review focuses on structural and functional comparisons of the various groups of photosynthetic reaction centers and considers possible evolutionary scenarios to explain the diversity of existing photosynthetic organisms.

  17. Protein structure, electron transfer and evolution of prokaryotic photosynthetic reaction centers

    Science.gov (United States)

    Blankenship, R. E.

    1994-01-01

    Photosynthetic reaction centers from a variety of organisms have been isolated and characterized. The groups of prokaryotic photosynthetic organisms include the purple bacteria, the filamentous green bacteria, the green sulfur bacteria and the heliobacteria as anoxygenic representatives as well as the cyanobacteria and prochlorophytes as oxygenic representatives. This review focuses on structural and functional comparisons of the various groups of photosynthetic reaction centers and considers possible evolutionary scenarios to explain the diversity of existing photosynthetic organisms.

  18. Genus specific unusual carotenoids in purple bacteria, Phaeospirillum and Roseospira: structures and biosyntheses.

    Science.gov (United States)

    Takaichi, Shinichi; Maoka, Takashi; Sasikala, Ch; Ramana, Ch V; Shimada, Keizo

    2011-07-01

    Phototrophic bacteria necessarily contain carotenoids for photosynthesis, and a few phototrophic purple bacteria accumulate unusual carotenoids. The carotenoids in the genera Phaeospirillum and Roseospira were identified using spectroscopic methods. All species of the genus Phaeospirillum contained characteristic polar carotenoids in addition to lycopene and hydroxylycopene (rhodopin); hydroxylycopene glucoside, dihydroxylycopene, and its mono- and/or diglucosides. From the structures of these carotenoids, their accumulation was suggested to be due to absence of CrtD (acyclic carotenoid C-3,4 desaturase) and to possession of glucosyltransferase. Species of the genus Roseospira have been reported to have unusual absorption spectra in acetone extract, and they were found to accumulate 3,4-didehydrorhodopin as a major carotenoid. This may be due to low activity of CrtF (acyclic 1-hydroxycarotenoid methyltransferase). The study concludes in identifying genus specific unusual carotenoids, which is probably due to characteristic nature of some carotenogenesis enzymes.

  19. An extended model for electron spin polarization in photosynthetic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Morris, A.L.; Norris, J.R. (Argonne National Lab., IL (USA) Chicago Univ., IL (USA). Dept. of Chemistry); Thurnauer, M.C. (Argonne National Lab., IL (USA))

    1990-01-01

    We have developed a general model for electron spin polarization which includes contributions from both CIDEP (chemically induced dynamic electron polarization) and CRP (correlated radical polarization). In this paper, we apply this model to sequential electron transfer in photosynthetic bacteria. Our model calculates the density matrix for the P{sup +}I{sup {minus}} radical pair and transfers the polarization as it develops to the P{sup +}Q{sup {minus}} radical pair. We illustrate several possible cases. One case is equivalent to CIDEP; no interactions are included on the secondary radical pair, P{sup +}Q{sup {minus}}. Another approximates CRPP by either increasing the transfer rate from P{sup +}I{sup {minus}} to P{sup +}Q{sup {minus}} or restricting interactions to the secondary radical pair, P{sup +}Q{sup {minus}}. Others allow interactions on both the primary and secondary radical pairs with various transfer rates. 15 refs., 4 figs.

  20. Factors influencing the purification efficiency of photosynthetic bacteria

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    One strain of photosynthetic bacteria (PSB) was isolated from substrate sludge offresh-water fishpond. Influence of the use level of PSB culture solution, illumination condition,temperature, salinity, the use level of copper sulfate and dipterex on the purification efficiency was investigated. The results showed that the optimum use level of PSB culture solution was 10 mg/L,and the purification efficiency at illumination was higher than that at black, and if the temperature was lower than 15℃, or the use level of sodium chloride, copper sulfate and dipterex were higherthan 10 000 mg/L, 0.4 mg/L and 2.0 mg/L, respectively, the purification efficiency dropped distinctly.

  1. "Paraffin wax-overlay of pour plate", a method for the isolation and enumeration of purple non-sulfur bacteria.

    Science.gov (United States)

    Archana, A; Sasikala, Ch; Ramana, Ch V; Arunasri, K

    2004-12-01

    A modification of pour plate technique with an overlay of wax was used for isolation and enumeration of purple non-sulfur bacteria (PNSB) with equal efficiency as that of agar shake culture. The total count of PNSB ranged from 10(5)-10(8) CFU g dry soil(-1) and belonged to the genera of Rhodobacter, Rhodopseudomonas, Rhodocista and Rubrivivax.

  2. Photosynthetic Characteristics of Purple-leaf Plants in Drought Region%干旱区3种彩叶植物的光合特性

    Institute of Scientific and Technical Information of China (English)

    庄红梅; 黄俊华; 李建贵; 石游

    2011-01-01

    The photosynthetic characteristics of three purple-leaf plants were studied in this research, the results would provide scientific guidance for configuring colorful plants in plant landscaping. The portable photosynthetic system LI-6400 (LI-COR company, U. S) was used to measure daily changes and light response curves of three years old purple-leaf lee (Prunus cerasifera Ehrhart f. Atropur-purea Jacq) , purple-leaf dwarf cherry (PrunusXcistena Pissardii) and purple-leaf peach (.Prunus per-sica cv. Atropurpurea). The light compensation point of purple-leaf peach, lee and dwarf cherry were 12, 24, 92 μmol ? M-2 ? S-1, respectively; light saturation point were 1 044, 688, 1 196 μmol ? M-2 ? S-1, respectively. The purple-leaf dwarf cherry showed some characters of heliophilous plants, so, in landscape configuration they should be placed in a upper level of a plants community . The purple-leaf lee and purple-leaf dwarf cherry have a clear photosynthetic "midday depression" around noon, which is mainly caused by the decline of stomatal conductance, while purple leaf peach is limited by non-stomatal factors. The transpiration rates of three tree species belong to the afternoon peak type. Diurnal temperature variation of the ground surface is greater than it in the ground ,and the surface humidity variation is inversely proportional to the diurnal ground surface temperature change.%以3a生紫叶李(Prunus cerasi era Ehrhart f.atropurpurea Jacq)、紫叶矮樱(Prunus×cistena Pis-sardii)、紫叶桃(Prunus persica cv.atropurpurea)为试材,研究3种彩叶植物的光合作用基本生理特征和规律.结果表明,紫叶桃、紫叶李和紫叶矮樱的光补偿点分别为12、24和92 μmol·m-2·s-1;光饱和点分别为1 044、688和1 196 μmol·m-2·s-1;表明紫叶矮樱较为喜阳,在园林绿化配置时应处于群落的上层.紫叶李与紫叶矮樱有明显的光合“午休”现象,主要是由气孔导度下降引起的,紫叶桃

  3. Theoretical study on primary reaction of photosynthetic bacteria

    Institute of Scientific and Technical Information of China (English)

    张纯喜; 樊红军; 李良璧; 匡廷云

    1999-01-01

    Theoretical calculation was carried out on the primary electron donor P870 of photosynthetic bacteria. The results show that: (ⅰ) the bimolecular structure of the primary electron donor is more advantageous in energy than monomolecular structure; (ⅱ) the initial configuration of primary electron donor is no longer stable and changes to the configuration with lower energy and chemical reactivity after the charge separation. In the P870, such structural change is completed through the rotation of C3 acetyl, so the oxygen atom of acetyl interacts with the magnesium atom of another bacterio-chlorophyll molecule, and the total energy and chemical reactivity are reduced evidently. It is suggested that the structural change of the primary electron donor is important in preventing the occurrence of charge recombination during the primary reaction and maintaining the high efficiency of the conversion of sun-light to chemical energy. A new mechanism of primary reaction has been proposed, which can give r

  4. Biological formation of 5-aminolevulinic acid by photosynthetic bacteria

    Institute of Scientific and Technical Information of China (English)

    LIU Xiu-yan; XU Xiang-yang; MA Qing-lan; WU Wei-hong

    2005-01-01

    In this study, 7 stains of Rhodopseudomonas sp. were selected from 36 photosynthetic bacteria stains storied in our laboratory.Rhodopseudomonas sp. strain 99-28 has the highest 5-aminolevulinic acid(ALA) production ability in these 7 strains. Rhodopseudomonas sp. 99-28 strain was mutated using ultraviolet radiation and a mutant strain L-1, which ALA production is higher than wild strain 99-28 about one times, was obtained. The elements affecting ALA formation of strain 99-28 and L-1 were studied. Under the optimal condition(pH 7.5,supplement of ALA dehydratase(ALAD) inhibitor, levulinic acid(LA) and precursors of ALA synthesis, glycine and succinat, 3000 Ix of light density), ALA formation of mutant L-1 was up to 22.15 mg/L. Strain L-1 was used to treat wastewater to remove CODCr and produce ALA. ALA production was 2.819 my/L, 1.531 rog/L, 2.166 mg/L, and 2.424 mg/L in monosodium glutamate wastewater(MGW),succotash wastewater(SW), brewage wastewater(BW), and citric acid wastewater(CAW) respectively. More than 90% of CODCr was removed in four kinds of wastewater. When LA, glycin and succinate were supplied, ALA production was dramatically increased,however, CODCr could hardly be removed.

  5. Continuous cultivation of photosynthetic bacteria for fatty acids production.

    Science.gov (United States)

    Kim, Dong-Hoon; Lee, Ji-Hye; Hwang, Yuhoon; Kang, Seoktae; Kim, Mi-Sun

    2013-11-01

    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) 4d, cell concentration continuously increased from 0.97 g dcw/L to 2.05 g dcw/L as lactate concentration increased from 30 mM to 60mM. At 70 mM, however, cell concentration fluctuated with incomplete substrate degradation. By installing a membrane unit to CFSTR, a stable performance was observed under much higher substrate loading (lactate 100mM and HRT 1.5d). A maximum cell concentration of 16.2g dcw/L, cell productivity of 1.9 g dcw/L/d, and FA productivity of 665 mg FA/L/d were attained, and these values were comparable with those achieved using microalgae. The FA content of R. sphaeroides was around 35% of dry cell weight, mainly composed of vaccenic acid (C18:1, omega-7).

  6. Seeing green bacteria in a new light: genomics-enabled studies of the photosynthetic apparatus in green sulfur bacteria and filamentous anoxygenic phototrophic bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Bryant, Donald A

    2004-01-01

    Based upon their photosynthetic nature and the presence of a unique light-harvesting antenna structure, the chlorosome, the photosynthetic green bacteria are defined as a distinctive group in the Bacteria. However, members of the two taxa that comprise this group, the green sulfur bacteria...... (Chlorobi) and the filamentous anoxygenic phototrophic bacteria ("Chloroflexales"), are otherwise quite different, both physiologically and phylogenetically. This review summarizes how genome sequence information facilitated studies of the biosynthesis and function of the photosynthetic apparatus...... and carotenoid species also allow the functions of these pigments to be studied in vivo....

  7. Biomarker evidence for green and purple sulphur bacteria in a stratified Palaeoproterozoic sea.

    Science.gov (United States)

    Brocks, Jochen J; Love, Gordon D; Summons, Roger E; Knoll, Andrew H; Logan, Graham A; Bowden, Stephen A

    2005-10-06

    The disappearance of iron formations from the geological record approximately 1.8 billion years (Gyr) ago was the consequence of rising oxygen levels in the atmosphere starting 2.45-2.32 Gyr ago. It marks the end of a 2.5-Gyr period dominated by anoxic and iron-rich deep oceans. However, despite rising oxygen levels and a concomitant increase in marine sulphate concentration, related to enhanced sulphide oxidation during continental weathering, the chemistry of the oceans in the following mid-Proterozoic interval (approximately 1.8-0.8 Gyr ago) probably did not yet resemble our oxygen-rich modern oceans. Recent data indicate that marine oxygen and sulphate concentrations may have remained well below current levels during this period, with one model indicating that anoxic and sulphidic marine basins were widespread, and perhaps even globally distributed. Here we present hydrocarbon biomarkers (molecular fossils) from a 1.64-Gyr-old basin in northern Australia, revealing the ecological structure of mid-Proterozoic marine communities. The biomarkers signify a marine basin with anoxic, sulphidic, sulphate-poor and permanently stratified deep waters, hostile to eukaryotic algae. Phototrophic purple sulphur bacteria (Chromatiaceae) were detected in the geological record based on the new carotenoid biomarker okenane, and they seem to have co-existed with communities of green sulphur bacteria (Chlorobiaceae). Collectively, the biomarkers support mounting evidence for a long-lasting Proterozoic world in which oxygen levels remained well below modern levels.

  8. Engineered photosynthetic bacteria, method of manufacture of biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Laible, Philip D.; Snyder, Seth W.

    2016-09-13

    The invention provides for a novel type of biofuel; a method for cleaving anchors from photosynthetic organisms; and a method for producing biofuels using photosynthetic organisms, the method comprising identifying photosynthesis co-factors and their anchors in the organisms; modifying the organisms to increase production of the anchors; accumulating biomass of the organisms in growth media; and harvesting the anchors.

  9. Spectroscopic studies of two spectral variants of light-harvesting complex 2 (LH2) from the photosynthetic purple sulfur bacterium Allochromatium vinosum.

    Science.gov (United States)

    Niedzwiedzki, Dariusz M; Bina, David; Picken, Nichola; Honkanen, Suvi; Blankenship, Robert E; Holten, Dewey; Cogdell, Richard J

    2012-09-01

    Two spectral forms of the peripheral light-harvesting complex (LH2) from the purple sulfur photosynthetic bacterium Allochromatium vinosum were purified and their photophysical properties characterized. The complexes contain bacteriochlorophyll a (BChl a) and multiple species of carotenoids. The composition of carotenoids depends on the light conditions applied during growth of the cultures. In addition, LH2 grown under high light has a noticeable split of the B800 absorption band. The influence of the change of carotenoid distribution as well as the spectral change of the excitonic absorption of the bacteriochlorophylls on the light-harvesting ability was studied using steady-state absorption, fluorescence and femtosecond time-resolved absorption at 77K. The results demonstrate that the change of the distribution of the carotenoids when cells were grown at low light adapts the absorptive properties of the complex to the light conditions and maintains maximum photon-capture performance. In addition, an explanation for the origin of the enigmatic split of the B800 absorption band is provided. This spectral splitting is also observed in LH2 complexes from other photosynthetic sulfur purple bacterial species. According to results obtained from transient absorption spectroscopy, the B800 band split originates from two spectral forms of the associated BChl a monomeric molecules bound within the same complex.

  10. 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

  11. Excitonic energy transfer in light-harvesting complexes in purple bacteria

    CERN Document Server

    Ye, Jun; Zhao, Yang; Yu, Yunjin; Lee, Chee Kong; Cao, Jianshu

    2012-01-01

    Two distinct approaches, the Frenkel-Dirac time-dependent variation and the Haken-Strobl model, are adopted to study energy transfer dynamics in single-ring and double-ring light-harvesting systems in purple bacteria. It is found that inclusion of long-range dipolar interactions in the two methods results in significant increases in intra- or inter-ring exciton transfer efficiency. The dependence of exciton transfer efficiency on trapping positions on single rings of LH2 (B850) and LH1 is similar to that in toy models with nearest-neighbor coupling only. However, owing to the symmetry breaking caused by the dimerization of BChls and dipolar couplings, such dependence has been largely suppressed. In the studies of coupled-ring systems, both methods reveal interesting role of dipolar interaction in increasing energy transfer efficiency by introducing multiple intra/inter-ring transfer paths. Importantly, the time scale (~4ps) of inter-ring exciton transfer obtained from polaron dynamics is in good agreement wit...

  12. The origin of the unusual Qy red shift in LH1-RC complexes from purple bacteria Thermochromatium tepidum as revealed by Stark absorption spectroscopy.

    Science.gov (United States)

    Ma, Fei; Yu, Long-Jiang; Wang-Otomo, Zheng-Yu; van Grondelle, Rienk

    2015-12-01

    Native LH1-RC of photosynthetic purple bacteria Thermochromatium (Tch.) tepidum, B915, has an ultra-red BChl a Qy absorption. Two blue-shifted complexes obtained by chemical modification, B893 and B882, have increasing full widths at half maximum (FWHM) and decreasing transition dipole oscillator strength. 77K Stark absorption spectroscopy studies were employed for the three complexes, trying to understand the origin of the 915 nm absorption. We found that Tr(∆α) and |∆μ| of both Qy and carotenoid (Car) bands are larger than for other purple bacterial LH complexes reported previously. Moreover, the red shifts of the Qy bands are associated with (1) increasing Tr(∆α) and |∆μ| of the Qy band, (2) the red shift of the Car Stark signal and (3) the increasing |∆μ| of the Car band. Based on the results and the crystal structure, a combined effect of exciton-charge transfer (CT) states mixing, and inhomogeneous narrowing of the BChl a site energy is proposed to be the origin of the 915 nm absorption. CT-exciton state mixing has long been found to be the origin of strong Stark signal in LH1 and special pair, and the more extent of the mixing in Tch. tepidum LH1 is mainly the consequence of the shorter BChl-BChl distances. The less flexible protein structure results in a smaller site energy disorder (inhomogeneous narrowing), which was demonstrated to be able to influence |∆μ| and absorption.

  13. Singlet-triplet fission of carotenoid excitation in light-harvesting LH2 complexes of purple phototrophic bacteria.

    Science.gov (United States)

    Klenina, I B; Makhneva, Z K; Moskalenko, A A; Gudkov, N D; Bolshakov, M A; Pavlova, E A; Proskuryakov, I I

    2014-03-01

    The current generally accepted structure of light-harvesting LH2 complexes from purple phototrophic bacteria conflicts with the observation of singlet-triplet carotenoid excitation fission in these complexes. In LH2 complexes from the purple bacterium Allochromatium minutissimum, a drop in the efficiency of carotenoid triplet generation is demonstrated, which correlates with the extent of selective photooxidation of bacteriochlorophylls absorbing at ~850 nm. We conclude that singlet-triplet fission of carotenoid excitation proceeds with participation of these excitonically coupled bacteriochlorophylls. In the framework of the proposed mechanism, the contradiction between LH2 structure and photophysical properties of carotenoids is eliminated. The possibility of singlet-triplet excitation fission involving a third mediator molecule was not considered earlier.

  14. Counting Viruses and Bacteria in Photosynthetic Microbial Mats

    OpenAIRE

    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 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 quantifica...

  15. Atomic force microscopy of bacterial photosynthetic systems: a new model for native membrane organization

    NARCIS (Netherlands)

    Bahatyrova, Svetlana

    2005-01-01

    The main goal of this thesis was to investigate the supramolecular architecture of a photosynthetic membrane from Rhodobacter sphaeroides purple bacteria cells. This is extremely timely, since we now know all of the structures of photosynthetic pigment-protein LH and RC complexes, ATP-synthase and b

  16. Growth and photosynthetic efficiency promotion of sugar beet (Beta vulgaris L.) by endophytic bacteria.

    Science.gov (United States)

    Shi, Yingwu; Lou, Kai; Li, Chun

    2010-07-01

    Very little is known about the physiological interactions between plants and endophytic bacteria. We investigated the impact of three endophytic bacteria, Bacillus pumilus 2-1, Chryseobacterium indologene 2-2, and Acinetobacter johnsonii 3-1, on the photosynthetic capacity and growth of sugar beet. Endophyte-free plants were obtained first and infected with the bacteria. Measurements of total chlorophyll content revealed very significant differences between endophyte-free beet plants and some infected by endophytic bacteria. The maximum photochemical yield (Fv/Fm) was used to determine any photosynthetic effect on plants caused by biotic or abiotic factors. After 30 days of growth, there was significantly higher Fv/Fm for endophyte-infected than endophyte-free plants. The light response curves of beet showed that photosynthetic capacity was significantly increased in endophyte-infected plants. Photosynthesis of endophyte-free plants was saturated at 1,300 micromol m(-2) s(-1), whereas endophyte-infected plants were not saturated at the irradiance used. The effect seemed to be due to promotion of electron transport in the thylakoid membranes. Promotion of photosynthetic capacity in sugar beet was due to increased chlorophyll content, leading to a consequent increased carbohydrate synthesis. It is possible that the increased maximum yield of photosynthesis in sugar beet was promoted by phytohormones and produced by the bacteria.

  17. Photoinduced ESR signals from the primary electron donors in deuterated highly /sup 13/C enriched photosynthetic bacteria and algae

    Energy Technology Data Exchange (ETDEWEB)

    Wasielewski, M.R.; Norris, J.R.; Crespi, H.L.; Harper, J.

    1981-12-16

    In purple photosynthetic bacteria such as Rhodopseudomonas sphaeroides the oxidized primary donar P865/sup +/ exhibits a single Gaussian ESR signal posessing a line width that is narrowed by 1/%2 relative to that of monomeric BChl a/sup +/ in vitro. Data show that P700/sup +/ from the green plant photosystem I donor is a single oxidized Chl a type macrocycle. New data confirm that P865/sup +/ is a dimer of a BChl a type macrocycle. A method that accounts for the entire spin is needed in order to count the number of spins per macrocycle. The solution to this problem is to make each carbon atom of the ..pi.. system over which the electron is distributed magnetic resonance active. This requires that each position in the ..pi.. framework be highly enriched in /sup 13/C. Under these conditions the total ESR line width is the sum of the hyperfine lines due to each carbon atom of the ..pi.. system. Data indicate that the spin in P700/sup +/ is located on only one Chl a type macrocycle whereas that of P865/sup +/ is shared between two BChl a type macrocycles. (MWF)

  18. CO2 assimilation in the chemocline of Lake Cadagno is dominated by a few types of phototrophic purple sulfur bacteria

    DEFF Research Database (Denmark)

    Storelli, Nicola; Peduzzi, Sandro; Saad, Maged

    2013-01-01

    Lake Cadagno is characterized by a compact chemocline that harbors high concentrations of various phototrophic sulfur bacteria. Four strains representing the numerically most abundant populations in the chemocline were tested in dialysis bags in situ for their ability to fix CO₂. The purple sulfur...... and form II of RuBisCO, respectively. Transcription analyses confirmed that, whereas cbbM remained poorly expressed throughout light and dark exposure, cbbL expression varied during the light-dark cycle and was affected by the available carbon sources. Interestingly, the peaks in cbbL expression did...

  19. The study of photo-induced ultrafast dynamics in light-harvesting complex LH2 of purple bacteria

    Institute of Scientific and Technical Information of China (English)

    LIU Wei-min; YAN Yong-li; LIU Kang-jun; XU Chun-he; QIAN Shi-xiong

    2006-01-01

    In this paper,we introduce the photo-induced ultrafast dynamics taking place in the peripheral light harvesting antenna LH2 from purple bacteria Rhodobacter sphaeroides by using absorption,fluorescence emission and ultrafast spectroscopic techniques.Three kinds of LH2 sampies,pH treated LH2 (complete removal of B800 pigments),carotenoid mutated LH2 (GM 309) and electrochemical oxidation treated LH2 were used in comparison with native LH2 to investigate the mechanism of photo-induced ultrafast energy transfer within the LH2 complex.

  20. Evanescent cultivation of photosynthetic bacteria on thin waveguides

    Science.gov (United States)

    Pierobon, S. C.; Ooms, M. D.; Sinton, D.

    2014-04-01

    Waveguides with thicknesses similar to biofilms (10-100 µm) provide an opportunity to improve the bioenergy density of biofilm photobioreactors, avoiding the fundamental light- and mass-transport productivity limitations of planktonic photobioreactors. This report investigates the biofilm growth of a mutant of Synechococcus elongatus (PCC 7942) in evanescent light fields that can be scaled over large planar areas. In this study, areas of 7.2 cm2 are illuminated via frustrated total internal reflections on planar waveguides. The resulting photosynthetic biofilm growth showed resilience to surface intensities exceeding photosynthetic limits and a more uniform cell density distribution (1.0 ± 0.3 × 109 mL-1) than predicted from surface light distribution profiles. These results indicate potential for larger area biofilms using the uniform lighting conditions identified. The combination of evanescent illumination with biofilms indicates a modular reactor cell density on the order of 108 mL-1, representing a two orders of magnitude improvement over current facility architectures, with significant potential for further improvement through denser biofilms.

  1. Stark absorption spectroscopy on the carotenoids bound to B800-820 and B800-850 type LH2 complexes from a purple photosynthetic bacterium, Phaeospirillum molischianum strain DSM120.

    Science.gov (United States)

    Horibe, Tomoko; Qian, Pu; Hunter, C Neil; Hashimoto, Hideki

    2015-04-15

    Stark absorption spectroscopy was applied to clarify the structural differences between carotenoids bound to the B800-820 and B800-850 LH2 complexes from a purple photosynthetic bacterium Phaeospirillum (Phs.) molischianum DSM120. The former complex is produced when the bacteria are grown under stressed conditions of low temperature and dim light. These two LH2 complexes bind carotenoids with similar composition, 10% lycopene and 80% rhodopin, each with the same number of conjugated CC double bonds (n=11). Quantitative classical and semi-quantum chemical analyses of Stark absorption spectra recorded in the carotenoid absorption region reveal that the absolute values of the difference dipole moments |Δμ| have substantial differences (2 [D/f]) for carotenoids bound to either B800-820 or B800-850 complexes. The origin of this striking difference in the |Δμ| values was analyzed using the X-ray crystal structure of the B800-850 LH2 complex from Phs. molischianum DSM119. Semi-empirical molecular orbital calculations predict structural deformations of the major carotenoid, rhodopin, bound within the B800-820 complex. We propose that simultaneous rotations around neighboring CC and CC bonds account for the differences in the 2 [D/f] of the |Δμ| value. The plausible position of the rotation is postulated to be located around C21-C24 bonds of rhodopin.

  2. On the role of cytochrome c8 in photosynthetic electron transfer of the purple non-sulfur bacterium Rhodoferax fermentans

    DEFF Research Database (Denmark)

    Hochkoeppler, Alejandro; Ciurli, Stefano; Kofod, Pauli

    1997-01-01

    of +285 mV. Partial analysis of the N-terminus amino-acid sequence shows a high similarity with cytochromes of c8 type (formerly called Pseudomonas cytochrome c-551 type). Time-resolved spectrophotometric studies show that this cytochrome c8 reduces the tetraheme subunit of the photosynthetic reaction...

  3. Okenane, a biomarker for purple sulfur bacteria (Chromatiaceae), and other new carotenoid derivatives from the 1640 Ma Barney Creek Formation

    Science.gov (United States)

    Brocks, Jochen J.; Schaeffer, Philippe

    2008-03-01

    Carbonates of the 1640 million years (Ma) old Barney Creek Formation (BCF), McArthur Basin, Australia, contain more than 22 different C 40 carotenoid derivatives including lycopane, γ-carotane, β-carotane, chlorobactane, isorenieratane, β-isorenieratane, renieratane, β-renierapurpurane, renierapurpurane and the monoaromatic carotenoid okenane. These biomarkers extend the geological record of carotenoid derivatives by more than 1000 million years. Okenane is potentially derived from the red-colored aromatic carotenoid okenone. Based on a detailed review of the ecology and physiology of all extant species that are known to contain okenone, we interpret fossil okenane as a biomarker for planktonic purple sulfur bacteria of the family Chromatiaceae. Okenane is strictly a biomarker for anoxic and sulfidic conditions in the presence of light (photic zone euxinia) and indicates an anoxic/oxic transition (temporarily) located at less than 25 m depth and, with a high probability, less than 12 m depth. For the BCF, we also interpret renierapurpurane, renieratane and β-renierapurpurane as biomarkers for Chromatiaceae with a possible contribution of cyanobacterial synechoxanthin to the renierapurpurane pool. Although isorenieratane may, in principle, be derived from actinobacteria, in the BCF these biomarkers almost certainly derive from sulfide-oxidizing phototrophic green sulfur bacteria (Chlorobiaceae). Biological precursors of γ-carotane, β-carotane and lycopane are found among numerous autotrophic and almost all phototrophic organisms in the three domains of life. In the BCF, a paucity of diagnostic eukaryotic steroids suggests that algae were rare and, therefore, that cyanobacterial carotenoids such as β-carotene, echinenone, canthaxanthin and zeaxanthin are the most likely source of observed β-carotane. γ-Carotane may be derived from cyanobacteria, Chlorobiaceae and green non-sulfur bacteria (Chloroflexi), while the most likely biological sources for lycopane

  4. Rapid redox signal transmission by "Cable Bacteria" beneath a photosynthetic biofilm.

    Science.gov (United States)

    Malkin, S Y; Meysman, F J R

    2015-02-01

    Recently, long filamentous bacteria, belonging to the family Desulfobulbaceae, were shown to induce electrical currents over long distances in the surface layer of marine sediments. These "cable bacteria" are capable of harvesting electrons from free sulfide in deeper sediment horizons and transferring these electrons along their longitudinal axes to oxygen present near the sediment-water interface. In the present work, we investigated the relationship between cable bacteria and a photosynthetic algal biofilm. In a first experiment, we investigated sediment that hosted both cable bacteria and a photosynthetic biofilm and tested the effect of an imposed diel light-dark cycle by continuously monitoring sulfide at depth. Changes in photosynthesis at the sediment surface had an immediate and repeatable effect on sulfide concentrations at depth, indicating that cable bacteria can rapidly transmit a geochemical effect to centimeters of depth in response to changing conditions at the sediment surface. We also observed a secondary response of the free sulfide at depth manifest on the time scale of hours, suggesting that cable bacteria adjust to a moving oxygen front with a regulatory or a behavioral response, such as motility. Finally, we show that on the time scale of days, the presence of an oxygenic biofilm results in a deeper and more acidic suboxic zone, indicating that a greater oxygen supply can enable cable bacteria to harvest a greater quantity of electrons from marine sediments. Rapid acclimation strategies and highly efficient electron harvesting are likely key advantages of cable bacteria, enabling their success in high sulfide generating coastal sediments.

  5. Distribution Pattern of Photosynthetic Picoplankton and Heterotrophic Bacteria in the Northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    Yu-Ming Cai; Xiu-Ren Ning; Cheng-Gang Liu; Qiang Hao

    2007-01-01

    The environmental regulation of picoplankton distribution in the northern South China Sea was examined in winter and summer of 2004. The average abundance of Synechococcus, Prochlorococcus, and heterotrophic bacteria was lower in winter (30, 21, and 780×103 cells/cm3, respectively) than in summer (53, 85, and 1 090×103 cells/cm3,respectively), but the seasonal pattern was opposite for plcoeukaryotic phytoplankton (4 500 and 3 200 cells/cm3 in winter and summer, respectively). Synechococcus, picoeukaryotes, and bacteria were most abundant in the nutrient-rich coastal zone and continental shelf, but Prochlorococcus was most abundant in the continental slope and open ocean. The vertical distribution of each photosynthetic group and heterotrophic bacteria changed between the two seasons. Synechococcus populations with apparently different phycoerythrobilln content occurred at many stations in the summer. In addition, two different populations of Prochlorococcus were found: (i) small, weakly fluorescing cells in the surface layer; and (ii) larger, strongly fluorescent cells in the deep layer. The distribution pattern of photosynthetic picoplankton and heterotrophic bacteria depends on environmental effects and their ecophysiological differences. The distribution of Synechococcus appeared to be related to nutrient availability,whereas the distribution of Prochlorococcus appeared to be limited by temperature. Synechococcus was the only picophytoplankton with a consistent strong relationship with bacteria.

  6. Local electrostatic field induced by the carotenoid bound to the reaction center of the purple photosynthetic bacterium Rhodobacter sphaeroides.

    Science.gov (United States)

    Yanagi, Kazuhiro; Shimizu, Madoka; Hashimoto, Hideki; Gardiner, Alastair T; Roszak, Aleksander W; Cogdell, Richard J

    2005-01-20

    Electroabsorption (EA) spectra were recorded in the region of the reaction center (RC) Qy absorption bands of bacteriochlorophyll (Bchl) and bacteriopheophytin, to investigate the effect of carotenoid (Car) on the electrostatic environment of the RCs of the purple bacterium Rhodobacter (Rb.) sphaeroides. Two different RCs were prepared from Rb. sphaeroides strain R26.1 (R26.1-RC); R26.1 RC lacking Car and a reconstituted RC (R26.1-RC+ Car) prepared by incorporating a synthetic Car (3,4-dihydrospheroidene). Although there were no detectable differences between these two RCs in their near infrared (NIR) absorption spectra at 79 and 293 K, or in their EA spectra at 79 K, significant differences were detected in their EA spectra at 293 K. Three nonlinear optical parameters of each RC were determined in order to evaluate quantitatively these differences; transition dipole-moment polarizability and hyperpolarizability (D factor), the change in polarizability upon photoexcitation (Deltaalpha), and the change in dipole-moment upon photoexcitation (Deltamu). The value of D or Deltaalpha determined for each absorption band of the two RC samples showed similar values at 77 or 293 K. However, the Deltamu values of the special pair Bchls (P) and the monomer Bchls absorption bands showed significant differences between the two RCs at 293 K. X-ray crystallography of the two RCs has revealed that a single molecule of the solubilizing detergent LDAO occupies part of the carotenoid binding site in the absence of a carotenoid. The difference in the value of Deltamu therefore represents the differential effect of the detergent LDAO and the carotenoid on P. The change of electrostatic field around P induced by the presence of Car was determined to be 1.7 x 10(5) [V/cm], corresponding to a approximately 10% change in the electrostatic field around P.

  7. Structure analysis and comparative characterization of the cytochrome c' and flavocytochrome c from thermophilic purple photosynthetic bacterium Thermochromatium tepidum.

    Science.gov (United States)

    Hirano, Yu; Kimura, Yukihiro; Suzuki, Hideaki; Miki, Kunio; Wang, Zheng-Yu

    2012-08-21

    The thermodynamic and spectroscopic properties of two soluble electron transport proteins, cytochrome (Cyt) c' and flavocytochrome c, isolated from thermophilic purple sulfur bacterium Thermochromatium (Tch.) tepidum were examined and compared with those of the corresponding proteins from a closely related mesophilic bacterium Allochromatium (Alc.) vinosum. These proteins share sequence identities of 82% for the cytochromes c' and 86% for the flavocytochromes c. Crystal structures of the two proteins have been determined at high resolutions. Differential scanning calorimetry and denaturing experiments show that both proteins from Tch. tepidum are thermally and structurally much more stable than their mesophilic counterparts. The denaturation temperature of Tch. tepidum Cyt c' was 22 °C higher than that of Alc. vinosum Cyt c', and the midpoints of denaturation using guanidine hydrochloride were 2.0 and 1.2 M for the Tch. tepidum and Alc. vinosum flavocytochromes c, respectively. The enhanced stabilities can be interpreted on the basis of the structural and sequence information obtained in this study: increased number of hydrogen bonds formed between main chain nitrogen and oxygen atoms, more compact structures and reduced number of glycine residues. Many residues with large side chains in Alc. vinosum Cyt c' are substituted by alanines in Tch. tepidum Cyt c'. Both proteins from Tch. tepidum exhibit high structural similarities to their counterparts from Alc. vinosum, and the different residues between the corresponding proteins are mainly located on the surface and exposed to the solvent. Water molecules are found in the heme vicinity of Tch. tepidum Cyt c' and form hydrogen bonds with the heme ligand and C-terminal charged residues. Similar bound waters are also found in the vicinity of one heme group in the diheme subunit of Tch. tepidum flavocytochrome c. Electron density map of the Tch. tepidum flavocytochrome c clearly revealed the presence of disulfur atoms

  8. Improved hydrogen production by coupled systems of hydrogenase negative photosynthetic bacteria and fermentative bacteria in reverse micelles

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Anita [Centre for Biotechnology, University of Allahabad, Allahabad 211002 (India); Misra, Krishna [Indo-Russian Center for Bioinformatics, Indian Institute of Information Technology, Allahabad 211011 (India)

    2008-11-15

    Significant improvement in biological hydrogen production is achieved by the use of coupled bacterial cells in reverse micellar systems. Two coupled systems (a) Rhodopseudomonas palustris CGA009/Citrobacter Y19, and (b) Rhodobacter sphaeroides 2.4.1/Citrobacter Y19 bacteria have been immobilized separately in aqueous pool of the reverse micelles fabricated by various surfactants (AOT, CBAC and SDS) and apolar organic solvents (benzene and isooctane). The gene for uptake hydrogenase enzyme has been manipulated further for hydrogen generation. Mutants deficient in uptake hydrogenase (Hup{sup -}) were obtained from R. palustris CGA009 and R. sphaeroides 2.4.1, and entrapped with Citrobacter Y19 in the reverse micellar systems. More than two fold increase in hydrogen production was obtained by the use of Hup{sup -} mutants instead of wild-type photosynthetic bacteria together with Citrobacter Y19. Addition of sodium dithionite, a reducing agent to AOT/H{sub 2}O/isooctane reverse micellar system with the coupled systems of wild-type photosynthetic bacteria and fermentative bacterium Y19 effected similar increase in hydrogen production rate as it is obtained by the use of mutants. CBAC/H{sub 2}O/isooctane reverse micellar system is used for the first time for hydrogen production and is as promising as AOT/H{sub 2}O/isooctane reverse micellar system. All reverse micellar systems of coupled bacterial cultures gave encouraging hydrogen production (rate as well as yield) compared to uncoupled bacterial culture. (author)

  9. Photocurrent Generation by Photosynthetic Purple Bacterial Reaction Centers Interfaced with a Porous Antimony-Doped Tin Oxide (ATO) Electrode.

    Science.gov (United States)

    Carey, Anne-Marie; Zhang, HaoJie; Mieritz, Daniel; Volosin, Alex; Gardiner, Alastair T; Cogdell, Richard J; Yan, Hao; Seo, Dong-Kyun; Lin, Su; Woodbury, Neal W

    2016-09-28

    The ability to exchange energy and information between biological and electronic materials is critical in the development of hybrid electronic systems in biomedicine, environmental sensing, and energy applications. While sensor technology has been extensively developed to collect detailed molecular information, less work has been done on systems that can specifically modulate the chemistry of the environment with temporal and spatial control. The bacterial photosynthetic reaction center represents an ideal photonic component of such a system in that it is capable of modifying local chemistry via light-driven redox reactions with quantitative control over reaction rates and has inherent spectroscopic probes for monitoring function. Here a well-characterized model system is presented, consisting of a transparent, porous electrode (antimony-doped tin oxide) which is electrochemically coupled to the reaction center via a cytochrome c molecule. Upon illumination, the reaction center performs the 2-step, 2-electron reduction of a ubiquinone derivative which exchanges with oxidized quinone in solution. Electrons from the electrode then move through the cytochrome to reoxidize the reaction center electron donor. The result is a facile platform for performing redox chemistry that can be optically and electronically controlled in time and space.

  10. Purple-bacterial photosynthetic reaction centers and quantum-dot hybrid-assemblies in lecithin liposomes and thin films.

    Science.gov (United States)

    Lukashev, Eugeny P; Knox, Petr P; Gorokhov, Vladimir V; Grishanova, Nadezda P; Seifullina, Nuranija Kh; Krikunova, Maria; Lokstein, Heiko; Paschenko, Vladimir Z

    2016-11-01

    Quantum dots (QDs) absorb ultraviolet and long-wavelength visible light energy much more efficiently than natural bacterial light-harvesting proteins and can transfer the excitation energy to photosynthetic reaction centers (RCs). Inclusion of RCs combined with QDs as antennae into liposomes opens new opportunities for using such hybrid systems as a basis for artificial energy-transforming devices that potentially can operate with greater efficiency and stability than devices based only on biological components or inorganic components alone. RCs from Rhodobacter sphaeroides and QDs (CdSe/ZnS with hydrophilic covering) were embedded in lecithin liposomes by extrusion of a solution of multilayer lipid vesicles through a polycarbonate membrane or by dialysis of lipids and proteins dispersed with excess detergent. The efficiency of RC and QD interaction within the liposomes was estimated using fluorescence excitation spectra of the photoactive bacteriochlorophyll of the RCs and by measuring the fluorescence decay kinetics of the QDs. The functional activity of the RCs in hybrid complexes was fully maintained, and their stability was even increased. The efficiency of energy transfer between QDs and RCs and conditions of long-term stability of function of such hybrid complexes in film preparations were investigated as well. It was found that dry films containing RCs and QDs, maintained at atmospheric humidity, are capable of maintaining their functional activity for at least some months as judged by measurements of their spectral characteristics, efficiency of energy transfer from QDs to RCs and RC electron transport activity. Addition of trehalose to the films increases the stability further, especially for films maintained at low humidity. These stable hybrid film structures are promising for further studies towards developing new phototransformation devices for biotechnological applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Coherence in the B800 Ring of Purple Bacteria LH2

    Science.gov (United States)

    Cheng, Y. C.; Silbey, R. J.

    2006-01-01

    We study the quantum coherence in the B800 ring and how it affects the dynamics of excitation energy transfer (EET) in photo-synthetic light-harvesting systems. From an analysis of the spectrum, we determine the disorder parameters for the B800 ring and show that the relatively weak electronic coupling between B800 pigments subtly changes the dynamics of EET and improves the uniformity and robustness of B800→B850 EET at room temperature, an example of how a multichromophoric assembly can exploit coherence to optimize the efficiency of photosynthesis. A molecular-level description for the dynamics of EET in the light-harvesting system may prove useful for understanding other nanoscale molecular assemblies and designing efficient nanoscale optical devices.

  12. Pleiotropic effects of puf interposon mutagenesis on carotenoid biosynthesis in Rubrivivax gelatinosus. A new gene organization in purple bacteria.

    Science.gov (United States)

    Ouchane, S; Picaud, M; Vernotte, C; Reiss-Husson, F; Astier, C

    1997-01-17

    Rubrivivax gelatinosus mutants affected in the carotenoid biosynthesis pathways were created by interposon mutagenesis within the puf operon. Genetic and biochemical analysis of several constructed mutants suggest that at least crtC is localized downstream of the puf operon and that it is cotranscribed with this operon. Sequence analysis confirmed the genetic data and showed the presence of crtD and crtC genes downstream of the puf operon, a localization different from that known for other purple bacteria. Inactivation of the crtD gene indicated that the two crt genes are cotranscribed and that they are involved not only in the hydroxyspheroidene biosynthesis pathway as in Rhodobacter sphaeroides and R. capsulatus, but also in the spirilloxanthin biosynthesis pathway. Carotenoid genes implicated in the spirilloxanthin biosynthesis pathway were thus identified for the first time. Furthermore, analysis of carotenoid synthesis in the mutants gave genetic evidence that crtD and crtC genes are cotranscribed with the puf operon using the oxygen-regulated puf promoter.

  13. CO₂ assimilation in the chemocline of Lake Cadagno is dominated by a few types of phototrophic purple sulfur bacteria.

    Science.gov (United States)

    Storelli, Nicola; Peduzzi, Sandro; Saad, Maged M; Frigaard, Niels-Ulrik; Perret, Xavier; Tonolla, Mauro

    2013-05-01

    Lake Cadagno is characterized by a compact chemocline that harbors high concentrations of various phototrophic sulfur bacteria. Four strains representing the numerically most abundant populations in the chemocline were tested in dialysis bags in situ for their ability to fix CO₂. The purple sulfur bacterium Candidatus 'Thiodictyon syntrophicum' strain Cad16(T) had the highest CO₂ assimilation rate in the light of the four strains tested and had a high CO₂ assimilation rate even in the dark. The CO₂ assimilation of the population represented by strain Cad16(T) was estimated to be up to 25% of the total primary production in the chemocline. Pure cultures of strain Cad16(T) exposed to cycles of 12 h of light and 12 h of darkness exhibited the highest CO₂ assimilation during the first 4 h of light. The draft genome sequence of Cad16(T) showed the presence of cbbL and cbbM genes, which encode form I and form II of RuBisCO, respectively. Transcription analyses confirmed that, whereas cbbM remained poorly expressed throughout light and dark exposure, cbbL expression varied during the light-dark cycle and was affected by the available carbon sources. Interestingly, the peaks in cbbL expression did not correlate with the peaks in CO₂ assimilation.

  14. C-type cytochromes in the photosynthetic electron transfer pathways in green sulfur bacteria and heliobacteria.

    Science.gov (United States)

    Azai, Chihiro; Tsukatani, Yusuke; Itoh, Shigeru; Oh-oka, Hirozo

    2010-06-01

    Green sulfur bacteria and heliobacteria are strictly anaerobic phototrophs that have homodimeric type 1 reaction center complexes. Within these complexes, highly reducing substances are produced through an initial charge separation followed by electron transfer reactions driven by light energy absorption. In order to attain efficient energy conversion, it is important for the photooxidized reaction center to be rapidly rereduced. Green sulfur bacteria utilize reduced inorganic sulfur compounds (sulfide, thiosulfate, and/or sulfur) as electron sources for their anoxygenic photosynthetic growth. Membrane-bound and soluble cytochromes c play essential roles in the supply of electrons from sulfur oxidation pathways to the P840 reaction center. In the case of gram-positive heliobacteria, the photooxidized P800 reaction center is rereduced by cytochrome c-553 (PetJ) whose N-terminal cysteine residue is modified with fatty acid chains anchored to the cytoplasmic membrane.

  15. Fruit Setting Rate and Major Photosynthetic Characteristics of Purple Chili Peppers During Summer Conditions%紫色辣椒夏季坐果率及其主要光合特性分析

    Institute of Scientific and Technical Information of China (English)

    隋益虎; 钱春桃; 陈劲枫; 史建磊; 胡能兵; 曹玉杰

    2011-01-01

    An experiment was conducted in a plastic greenhouse to assess fruit setting rate and major photosynthetic and chlorophyll characteristics of purple and green chili pepper varieties in summer. For self fruit setting studies, 18 and 21 purple and green varieties, respectively were hand pollinated at blossom bud stage. Similarly, 10 purple and 9 green chili peppers were randomly selected for reciprocal hybridization to evaluate cross fruit setting rate. Main parameters of photosynthesis and chlorophyll fluorescence were measured from 5 varieties of chili pepper with diverse leaf colours, green 7035, high purple 7033, medium purple 7037, slight purple 7034 (with purple veins), and slight purple 7039 (with green veins)to assess the pigment content. The following results were obtained: ( 1 ) significantly higher fruit self-setting rate of purple (72.19%) than the green chili peppers (37.12%), significantly higher fruit cross-setting rate was recorded. The fruit cross setting rate was 55.99 and 21.60% when purple and green chili pepper varieties were used as female parents respectively. (2) the mount anthocyanin (An) and ratio of chlorophyll a and b (Chl. a/b) were significantly higher in leaves of purple chili than the green ones,mount Chl. a and carotenoid (Car) were also higher in most purple chili peppers, but insignificantly in amount Chl. b. (3) transpiration rate (Tr), stomatal conductance (Gs) and net photosynthetic rate (Pn)of purple and green chili pepper showed a similar trend of double peak curve. Light compensation point (LCP), light saturation point (LSP) and actual Pn during the day time of high temperatures were significantly higher while apparent quantum efficiency (AQY) were lower in all purple varieties than the green ones. (4) purple chili pepper could prevent excessive absorption of solar energy by pigment antennas besides by partly reversible inactivation of the reaction center (RC) of photosystem Ⅱ (PS Ⅱ)to reduce the harm of excess energy

  16. Unraveling the Electronic Structure of Individual Photosynthetic Pigment-Protein Complexes

    NARCIS (Netherlands)

    Oijen, Antoine M. van; Ketelaars, Martijn; Köhler, Jürgen; Aartsma, Thijs J.; Schmidt, Jan

    1999-01-01

    Low-temperature single-molecule spectroscopic techniques were applied to a light-harvesting pigment-protein complex (LH2) from purple photosynthetic bacteria. The properties of the electronically excited states of the two circular assemblies (B800 and B850) of bacteriochlorophyll a (BChl a) pigment

  17. Triplet state dynamics of chlorophylls in photosynthetic reaction centers and model systems.

    NARCIS (Netherlands)

    Wijk, van F.G.H.

    1987-01-01

    In this work the temperature dependence of the lineshape, and more specifically, the electron spin polarization pattern of the Δm = ±1 triplet EPR (Electron Paramagnetic Resonance) spectra from several photosynthetic purple bacteria has been investigated.In Chapter I a general introduction is presen

  18. Unraveling the Electronic Structure of Individual Photosynthetic Pigment-Protein Complexes

    NARCIS (Netherlands)

    Oijen, Antoine M. van; Ketelaars, Martijn; Köhler, Jürgen; Aartsma, Thijs J.; Schmidt, Jan

    1999-01-01

    Low-temperature single-molecule spectroscopic techniques were applied to a light-harvesting pigment-protein complex (LH2) from purple photosynthetic bacteria. The properties of the electronically excited states of the two circular assemblies (B800 and B850) of bacteriochlorophyll a (BChl a) pigment

  19. Exploring photosynthesis evolution by comparative analysis of metabolic networks between chloroplasts and photosynthetic bacteria

    Directory of Open Access Journals (Sweden)

    Hou Jing

    2006-04-01

    findings are consistent with the notion that since the light energy absorption, transfer and conversion is highly efficient even in photosynthetic bacteria, the further improvements in photosynthetic efficiency in higher plants may rely on changes in metabolic network properties.

  20. Photosynthetic aeration in biological wastewater treatment using immobilized microalgae-bacteria symbiosis.

    Science.gov (United States)

    Praveen, Prashant; Loh, Kai-Chee

    2015-12-01

    Chlorella vulgaris encapsulated in alginate beads were added into a bioreactor treating synthetic wastewater using Pseudomonas putida. A symbiotic CO2/O2 gas exchange was established between the two microorganisms for photosynthetic aeration of wastewater. During batch operation, glucose removal efficiency in the bioreactor improved from 50% in 12 h without aeration to 100% in 6 h, when the bioreactor was aerated photosynthetically. During continuous operation, the bioreactor was operated at a low hydraulic retention time of 3.3 h at feed concentrations of 250 and 500 mg/L glucose. The removal efficiency at 500 mg/L increased from 73% without aeration to 100% in the presence of immobilized microalgae. The initial microalgae concentration was critical to achieve adequate aeration, and the removal rate increased with increasing microalgae concentration. The highest removal rate of 142 mg/L-h glucose was achieved at an initial microalgae concentration of 190 mg/L. Quantification of microalgae growth in the alginate beads indicated an exponential growth during symbiosis, indicating that the bioreactor performance was limited by oxygen production rates. Under symbiotic conditions, the chlorophyll content of the immobilized microalgae increased by more than 30%. These results indicate that immobilized microalgae in symbiosis with heterotrophic bacteria are promising in wastewater aeration.

  1. Photosynthetic characteristics of marine aerobic anoxygenic phototrophic bacteria Roseobacter and Erythrobacter strains.

    Science.gov (United States)

    Sato-Takabe, Yuki; Hamasaki, Koji; Suzuki, Koji

    2012-05-01

    A coastal Roseobacter strain of marine aerobic anoxygenic phototrophic bacteria (AAnPB) was isolated and phylogenetically determined. The strain OBYS 0001 was characterized by its physiological and biochemical properties with reference to the Erythrobacter longus type strain NBRC 14126. When grown in batch cultures, the growth curves of the both strains were similar. Cellular bacteriochlorophyll a concentrations of the strains reached the maxima in the stationary growth conditions. In vivo fluorescence excitation/optical density spectra between 470 and 600 nm for OBYS 0001 represented higher values than NBRC 14126. Variable fluorescence measurements revealed that the functional absorption cross section (σ) of the bacterial photosynthetic complexes for OBYS 0001 was significantly higher than that for NBRC 14126 under green excitation. These results suggest that Roseobacter can capture green light more efficiently than Erythrobacter for photosynthesis. The photochemical quantum efficiencies (F (v)/F (m)) of the bacterial photosynthetic complexes for OBYS 0001 were consistently lower than those for NBRC 14126. A relationship between the growth rate and F (v)/F (m) was significant for OBYS 0001, but that was not found for NBRC 14126. These results suggested that F (v)/F (m) for AAnPB could not be used as a proxy of the growth rate which is consistent with their mostly heterotrophic characters.

  2. Antenna organization in green photosynthetic bacteria. Progress report, July 1, 1985--June 30, 1987

    Energy Technology Data Exchange (ETDEWEB)

    Blankenship, R.E.

    1987-12-31

    This project is concerned with the structure and function of the unique antenna system found in the green photosynthetic bacteria. The antenna system in these organisms is contained within a vesicle known as a chlorosome, which is attached to the cytoplasmic side of the cell membrane. Additional antenna pigments and reaction centers are contained in integral membrane proteins. Energy absorbed by the bacteriochlorophyll c (BChl c) pigments in the chlorosome is transferred via a ``baseplate`` array of BChl a antenna pigments into the membrane and to the reaction center. A schematic model of chlorosome structure is shown. This project is aimed at increasing our understanding of the organization of the pigments in the chlorosome and how the antenna system functions.

  3. Biomass and pigments production in photosynthetic bacteria wastewater treatment: effects of light sources.

    Science.gov (United States)

    Zhou, Qin; Zhang, Panyue; Zhang, Guangming

    2015-03-01

    This study is aimed at enhancing biomass and pigments production together with pollution removal in photosynthetic bacteria (PSB) wastewater treatment via different light sources. Red, yellow, blue, white LED and incandescent lamp were used. Results showed different light sources had great effects on the PSB. PSB had the highest biomass production, COD removal and biomass yield with red LED. The corresponding biomass, COD removal and biomass yield reached 2580 mg/L, 88.6% and 0.49 mg-biomass/mg-COD-removal, respectively. The hydraulic retention time of wastewater treatment could be shortened to 72 h with red LED. Mechanism analysis showed higher ATP was produced with red LED than others. Light sources could significantly affect the pigments production. The pigments productions were greatly higher with LED than incandescent lamp. Yellow LED had the highest pigments production while red LED produced the highest carotenoid/bacteriochlorophyll ratio. Considering both efficiency and energy cost, red LED was the optimal light source.

  4. Denitrification of aging biogas slurry from livestock farm by photosynthetic bacteria.

    Science.gov (United States)

    Yang, Anqi; Zhang, Guangming; Yang, Guang; Wang, Hangyao; Meng, Fan; Wang, Hongchen; Peng, Meng

    2017-05-01

    Huge amount of aging biogas slurry is in urgent need to be treated properly. However, due to high NH3-N concentration and low C/N ratio, this aging biogas slurry is refractory for traditional methods. Its denitrification has become a big challenge. In this paper, photosynthetic bacteria (PSB) were employed to handle this problem. The results showed denitrification of aging biogas slurry by PSB treatment was promising. The highest removal efficiency of NH3-N reached 99.75%, much higher than all other treatments. The removal of NH3-N followed pseudo zero order reaction under dark-aerobic condition. The better inoculation rate for NH3-N removal was 30%; and aerobic condition was more beneficial for NH3-N removal than anaerobic condition because of different metabolic pathways. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Spectral Diffusion and Electron-Phonon Coupling of the B800 BChl a Molecules in LH2 Complexes from Three Different Species of Purple Bacteria

    Science.gov (United States)

    Baier, J.; Gabrielsen, M.; Oellerich, S.; Michel, H.; van Heel, M.; Cogdell, R.J.; Köhler, J.

    2009-01-01

    We have investigated the spectral diffusion and the electron-phonon coupling of B800 bacteriochlorophyll a molecules in the peripheral light-harvesting complex LH2 for three different species of purple bacteria, Rhodobacter sphaeroides, Rhodospirillum molischianum, and Rhodopseudomonas acidophila. We come to the conclusion that B800 binding pockets for Rhodobacter sphaeroides and Rhodopseudomonas acidophila are rather similar with respect to the polarity of the protein environment but that the packaging of the αβ-polypeptides seems to be less tight in Rb. sphaeroides with respect to the other two species. PMID:19883604

  6. Hybridization of cloned Rhodopseudomonas capsulata photosynthesis genes with DNA from other photosynthetic bacteria.

    OpenAIRE

    Beatty, J T; Cohen, S N

    1983-01-01

    The homology of Rhodopseudomonas capsulata DNA segments carrying photosynthesis genes with sequences present in total DNA from certain other photosynthetic and non-photosynthetic bacterial species was determined by hybridization. R. capsulata DNA fragments that carry loci for production of peptide components of the photosynthetic reaction center and light-harvesting I antenna complex were found to hybridize to DNA from some photosynthetic species. However, fragments that carry carotenoid or b...

  7. An Innovative Device to Convert Olive Mill Wastewater into a Suitable Effluent for Feeding Purple Non-Sulfur Photosynthetic Bacteria

    Directory of Open Access Journals (Sweden)

    Pietro Carlozzi

    2015-08-01

    Full Text Available A device (prototype with a working volume of 200 L was used to deplete olive mill wastewater (OMW of polyphenols. The OMW transformed into feedstock by means of the device was then used for feeding a lab-scale photobioreactor, just for testing the production of bioH2. The main novelty of this prototype consists in the combination of several adsorbent matrices and the exploitation of their synergic action. In this investigation, three matrices have been used: active carbon, Azolla and zeolite. The device was operated at an olive oil company located in the heart of the Chianti zone (Province of Florence, Italy. The efficiency of polyphenol removal obtained using the device was ≥96%. The multi-matrix effluent (MMeff generated was then used to obtain three different culture broths containing 25%, 50% and 100% of MMeff, respectively. The diluted (with water culture broths were suitable for hydrogen generation, with the highest hydrogen production rate (12.7 mL H2/Lculture/h being obtained using 50% MMeff. The hydrogen yields were: 334 mL H2/L of MMeff, when feeding the photofermenter with pure effluent (100%; 1308 mL H2/L of MMeff, with the half-diluted effluent (50%, v/v; and 432 mL H2/L of MMeff, with the highest-diluted effluent (25%, v/v.

  8. In vitro assessment of gastrointestinal viability of two photosynthetic bacteria, Rhodopseudomonas palustris and Rhodobacter sphaeroides

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The objectives of this study were to assess the potential of two photosynthetic bacteria (PSB), Rhodopseudomonas palustris HZ0301 and Rhodobacter sphaeroides HZ0302, as probiotics in aquaculture. The viability of HZ0301 and HZ0302 in simulated gastric transit conditions (pH 2.0, pH 3.0 and pH 4.0 gastric juices) and in simulated small intestinal transit conditions (pH 8.0, with or without 0.3% bile salts) was tested. The effects of HZ0301 and HZ0302 on the viability and permeability of intestinal epithelial cell in primary culture of tilapias, Oreochromis nilotica, were also detected. All the treatments were determined with three replicates. The simulated gastric transit tolerance of HZ0301 and HZ0302 strains was pH-dependent and correspondingly showed lower viability at pH 2.0 after 180 min compared with pH 3.0 and pH 4.0. Both HZ0301 and HZ0302 were tolerant to simulated small intestine transit with or without bile salts in our research. Moreover, there was no significant difference (P>0.05) among three treatments including the control and the groups treated with HZ0301 or HZ0302 both in intestinal epithelial cell viability and membrane permeability, showing no cell damage. In summary, this study demonstrated that HZ0301 and HZ0302 had high capacity of upper gastrointestinal transit tolerance and were relatively safe for intestinal epithelial cells of tilapias.

  9. Roseobacter-Like Bacteria in Red and Mediterranean Sea Aerobic Anoxygenic Photosynthetic Populations

    Science.gov (United States)

    Oz, Aia; Sabehi, Gazalah; Koblízek, Michal; Massana, Ramon; Béjà, Oded

    2005-01-01

    Bacteriochlorophyll a-containing aerobic anoxygenic phototrophs (AAnP) have been proposed to account for up to 11% of the total surface water microbial community and to potentially have great ecological importance in the world's oceans. Recently, environmental and genomic data based on analysis of the pufM gene identified the existence of α-proteobacteria as well as possible γ-like proteobacteria among AAnP in the Pacific Ocean. Here we report on analyses of environmental samples from the Red and Mediterranean Seas by using pufM as well as the bchX and bchL genes as molecular markers. The majority of photosynthesis genes retrieved from these seas were related to Roseobacter-like AAnP sequences. Furthermore, the sequence of a novel photosynthetic operon organization from an uncultured Roseobacter-like bacterial artificial chromosome retrieved from the Red Sea is described. The data show the presence of Roseobacter-like bacteria in Red and Mediterranean Sea AAnP populations in the seasons analyzed. PMID:15640208

  10. Asymmetrically acting lycopene beta-cyclases (CrtLm) from non-photosynthetic bacteria.

    Science.gov (United States)

    Tao, L; Picataggio, S; Rouvière, P E; Cheng, Q

    2004-03-01

    Carotenoids have important functions in photosynthesis, nutrition, and protection against oxidative damage. Some natural carotenoids are asymmetrical molecules that are difficult to produce chemically. Biological production of carotenoids using specific enzymes is a potential alternative to extraction from natural sources. Here we report the isolation of lycopene beta-cyclases that selectively cyclize only one end of lycopene or neurosporene. The crtLm genes encoding the asymmetrically acting lycopene beta-cyclases were isolated from non-photosynthetic bacteria that produced monocyclic carotenoids. Co-expression of these crtLm genes with the crtEIB genes from Pantoea stewartii (responsible for lycopene synthesis) resulted in the production of monocyclic gamma-carotene in Escherichia coli. The asymmetric cyclization activity of CrtLm could be inhibited by the lycopene beta-cyclase inhibitor 2-(4-chlorophenylthio)-triethylamine (CPTA). Phylogenetic analysis suggested that bacterial CrtL-type lycopene beta-cyclases might represent an evolutionary link between the common bacterial CrtY-type of lycopene beta-cyclases and plant lycopene beta- and epsilon-cyclases. These lycopene beta-cyclases may be used for efficient production of high-value asymmetrically cyclized carotenoids.

  11. Identification of a fourth family of lycopene cyclases in photosynthetic bacteria.

    Science.gov (United States)

    Maresca, Julia A; Graham, Joel E; Wu, Martin; Eisen, Jonathan A; Bryant, Donald A

    2007-07-10

    A fourth and large family of lycopene cyclases was identified in photosynthetic prokaryotes. The first member of this family, encoded by the cruA gene of the green sulfur bacterium Chlorobium tepidum, was identified in a complementation assay with a lycopene-producing strain of Escherichia coli. Orthologs of cruA are found in all available green sulfur bacterial genomes and in all cyanobacterial genomes that lack genes encoding CrtL- or CrtY-type lycopene cyclases. The cyanobacterium Synechococcus sp. PCC 7002 has two homologs of CruA, denoted CruA and CruP, and both were shown to have lycopene cyclase activity. Although all characterized lycopene cyclases in plants are CrtL-type proteins, genes orthologous to cruP also occur in plant genomes. The CruA- and CruP-type carotenoid cyclases are members of the FixC dehydrogenase superfamily and are distantly related to CrtL- and CrtY-type lycopene cyclases. Identification of these cyclases fills a major gap in the carotenoid biosynthetic pathways of green sulfur bacteria and cyanobacteria.

  12. A photosynthetic-plasmonic-voltaic cell: Excitation of photosynthetic bacteria and current collection through a plasmonic substrate

    Science.gov (United States)

    Samsonoff, Nathan; Ooms, Matthew D.; Sinton, David

    2014-01-01

    Excitation of photosynthetic biofilms using surface-confined evanescent light fields enables energy dense photobioreactors, while electrode-adhered biofilms can provide electricity directly. Here, we demonstrate concurrent light delivery and electron transport through a plasmonically excited metal film. Biofilms of cyanobacterium Synechococcus bacillaris on 50-nm gold films are excited via the Kretschmann configuration at λ = 670 nm. Cells show light/dark response to plasmonic excitation and grow denser biofilms, closer to the electrode surface, as compared to the direct irradiated case. Directly irradiated biofilms produced average electrical powers of 5.7 μW/m2 and plasmonically excited biofilms produced average electrical powers of 5.8 μW/m2, with individual biofilms producing as much as 12 μW/m2.

  13. A photosynthetic-plasmonic-voltaic cell: Excitation of photosynthetic bacteria and current collection through a plasmonic substrate

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-27

    Excitation of photosynthetic biofilms using surface-confined evanescent light fields enables energy dense photobioreactors, while electrode-adhered biofilms can provide electricity directly. Here, we demonstrate concurrent light delivery and electron transport through a plasmonically excited metal film. Biofilms of cyanobacterium Synechococcus bacillaris on 50-nm gold films are excited via the Kretschmann configuration at λ = 670 nm. Cells show light/dark response to plasmonic excitation and grow denser biofilms, closer to the electrode surface, as compared to the direct irradiated case. Directly irradiated biofilms produced average electrical powers of 5.7 μW/m{sup 2} and plasmonically excited biofilms produced average electrical powers of 5.8 μW/m{sup 2}, with individual biofilms producing as much as 12 μW/m{sup 2}.

  14. 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 %.

  15. Arsenic metabolism in purple nonsulfur bacteria%紫色非硫细菌的砷代谢机制

    Institute of Scientific and Technical Information of China (English)

    吕常江; 赵春贵; 杨素萍; 曲音波

    2012-01-01

    [目的]系统阐述紫色非硫细菌(PNSB)砷代谢机制和砷代谢基因簇的进化关系.[方法]通过生物信息学方法分析了PNSB砷代谢基因簇的分布、组成、排布方式.采用UV-Vis和HPLC-ICP-MS方法,研究了3个PNSB种类对砷的抗性、砷形态及价态的转化、砷在细胞中的积累和分布以及磷酸盐对As细胞毒性的影响.[结果]砷基因簇分析表明:已公布全基因组序列的17个PNSB菌株基因组中均含有以ars operon为核心的砷代谢基因簇,由1-4个操纵子组成,主要含有与细胞质砷还原和砷甲基化代谢相关的基因,但基因的组成和排列方式因种和菌株而异,尤其是arsM和两类进化来源不同的arsC.实验结果表明:光照厌氧条件下,3个PNSB种类对As(V)和As(Ⅲ)均具有抗性,As(V)和As(Ⅲ)均能进入细胞 ;在胞内As(V)能够还原为As(Ⅲ)并被排出胞外,但不能将As(Ⅲ)氧化为As(V),也未检测到甲基砷化物 ;磷酸盐浓度升高,能够抑制As(V)进入细胞,降低As(V)对细胞的毒性,而不能抑制As(Ⅲ)进入细胞.[结论]PNSB砷代谢机制主体为细胞质As(V)还原,也还有砷甲基化途径.通过对砷代谢基因簇结构多样性特点和进化方式分析,提出了与Rosen不同的ars operon进化途径.这对深入开展PNSB砷代谢和基因之间的相互作用研究奠定基础.%To elucidate the arsenic metabolic pathway of purple nonsulfur bacteria (PNSB). [Methods] We investigated the distribution within their genomes, organization, composition, arrangement, core genes and coding proteins of arsenic gene clusters found in complete genome from 17 strains of PNSB by comparing the genomes analysis, and studied the arsenic metabolism in 3 members of PNSB under anaerobic conditions by UV-Vis and HPLC-ICP-MS. [Results] Arsenate reduction and arsenite methylation pathways mediated by ars operon are the dominating arsenic metabolic processes. The arsenic gene clusters differ vastly in composition and

  16. Skin Anti-Aging Activities of Bacteriochlorophyll a from Photosynthetic Bacteria, Rhodobacter sphaeroides.

    Science.gov (United States)

    Kim, Nam Young; Yim, Tae Bin; Lee, Hyeon Yong

    2015-10-01

    In this work, the anti-aging skin effects of bacteriochlorophyll a isolated from Rhodobacter sphaeroides are first reported, with notably low cytotoxicity in the range of 1% to 14% in adding 0.00078 (% (w/w)) of the extracts, compared with the normal growth of both human dermal fibroblast and keratinocyte cells without any treatment as a control. The highest production of procollagen from human fibroblast cells (CCD-986sk) was observed as 221.7 ng/ml with 0.001 (% (w/w)) of bacteriochlorophyll a, whereas 150 and 200 ng/ml of procollagen production resulted from addition of 0.001 (% (w/w)) of the photosynthetic bacteria. The bacteriochlorophylla- induced TNF-α production increased to 63.8%, which was lower secretion from HaCaT cells than that from addition of 0.00005 (% (w/w)) of bacteriochlorophyll a. Additionally, bacteriochlorophyll a upregulated the expression of genes related to skin anti-aging (i.e., keratin 10, involucrin, transglutaminase-1, and MMPs), by up to 4-15 times those of the control. However, crude extracts from R. sphaeroides did not enhance the expression level of these genes. Bacteriochlorophyll a showed higher antioxidant activity of 63.8% in DPPH free radical scavenging than those of water, ethanol, and 70% ethanol extracts (14.0%, 57.2%, and 12.6%, respectively). It was also shown that the high antioxidant activity could be attributed to the skin anti-aging effect of bacteriochlorophyll a, although R. sphaeroides itself would not exhibit significant anti-aging activities.

  17. A Microsensor Study of the Interaction between Purple Sulfur and Green Sulfur Bacteria in Experimental Benthic Gradients

    DEFF Research Database (Denmark)

    Pringault, O.; de Wit, R.; Kühl, Michael

    1999-01-01

    The interaction between the purple sulfur bacterium Thiocapsa roseopersicina and the green sulfur bacterium Prosthecochloris aestuarii was studied in a gradient chamber under a 16-hours light-8-hours dark regime. The effects of interaction were inferred by comparing the final outcome of a mixed...... place during the dark periods, while the bottom layer grew phototrophically during the light periods only. In the mixed culture, the relative density of P. aestuarii was lower than in the axenic culture, which reflects the effects of the competition for sulfide. However, the relative density of T...

  18. Characterizing the Purple Earth: Modeling the Globally Integrated Spectral Variability of the Archean Earth

    Science.gov (United States)

    Sanromá, E.; Pallé, E.; Parenteau, M. N.; Kiang, N. Y.; Gutiérrez-Navarro, A. M.; López, R.; Montañés-Rodríguez, P.

    2014-01-01

    Ongoing searches for exoplanetary systems have revealed a wealth of planets with diverse physical properties. Planets even smaller than the Earth have already been detected and the efforts of future missions are aimed at the discovery, and perhaps characterization, of small rocky exoplanets within the habitable zone of their stars. Clearly, what we know about our planet will be our guideline for the characterization of such planets. However, the Earth has been inhabited for at least 3.8 Gyr and its appearance has changed with time. Here, we have studied the Earth during the Archean eon, 3.0 Gyr ago. At that time, one of the more widespread life forms on the planet was purple bacteria. These bacteria are photosynthetic microorganisms and can inhabit both aquatic and terrestrial environments. Here, we use a radiative transfer model to simulate the visible and near-infrared radiation reflected by our planet, taking into account several scenarios regarding the possible distribution of purple bacteria over continents and oceans. We find that purple bacteria have a reflectance spectrum that has a strong reflectivity increase, similar to the red edge of leafy plants, although shifted redward. This feature produces a detectable signal in the disk-averaged spectra of our planet, depending on cloud amount and purple bacteria concentration/distribution. We conclude that by using multi-color photometric observations, it is possible to distinguish between an Archean Earth in which purple bacteria inhabit vast extensions of the planet and a present-day Earth with continents covered by deserts, vegetation, or microbial mats.

  19. Antioxidant Activity in Vitro of Lactic Acid Bacteria Fermented Purple Sweet Potato%紫甘薯乳酸发酵醪体外抗氧化性研究

    Institute of Scientific and Technical Information of China (English)

    徐长亮; 张村雪; 郭秋实; 汤琳

    2012-01-01

    Five different fermentation broths were prepared by fermentation of purple sweet potato, red-core sweet potato, red jujube, apple juice or apple pomace by lactic acid bacteria. The total antioxidant capacity and DPPH free radical scavenging capacity of the fermentation broths and purple sweet potato vinegar were tested. Lactic acid bacteria fermentation resulted in a slight increase in the antioxidant activity of purple sweet potato. The total antioxidant capacity was increased to 200.18 mg/mL. The DPPH radical scavenging rate of fermented purple sweet potato was 96.99% at the dosage of 100 IzL, which was comparable to that of purple sweet potato vinegar. Purple sweet potato fermentation broth exhibited the strongest antioxidant activity among the five fermentation broths.%测定5种乳酸发酵醪和紫甘薯醋的总抗氧化能力和对二苯代苦昧酰基(DPPH)自由基清除率,结果表明紫:甘薯乳酸发酵后抗氧化能力轻微增强,总抗氧化能力达200.18mg/mL,添加量为100μL时对DPPH自由基清除率达96.99%,与紫甘薯醋抗氧化能力相当。5种乳酸发酵醪中,紫甘薯乳酸发酵醪抗氧化能力最强。

  20. PURPLE URINE BAG SYNDROME: AN ALARMING HUE?

    Directory of Open Access Journals (Sweden)

    Kumbha Thulasi Ram

    2015-02-01

    Full Text Available Purple urine bag syndrome is a rare phenomenon reported mostly in females on an indwelling catheter in chronically constipated with alkaline urine. It is secondary to recurrent urinary tract infections with indigo and indirubicin producing bacteria. Here we present this interesting case of an elderly woman who had purple colored urine bag

  1. Research Progress in Biological Hydrogen Production by Photosynthetic Bacteria%光合细菌生物制氢研究进展

    Institute of Scientific and Technical Information of China (English)

    张桂芝

    2011-01-01

    Hydrogen production mechanism of photosynthetic bacteria is introduced. The research progress in hydrogen production by photosynthetic bacteria on relevant strain screening, technological conditions, immobilization, photobioreactor, transport process of substance and energy and so on is reviewed. The existing problems and application foreground of hydrogen production by photosynthetic bacteria are discussed.%介绍了光合细菌产氢机理;综述了光合细菌制氢相关的菌种选育、工艺条件、固定化技术、光生物反应器以及物质和能量输运过程等方面的研究现状;阐述了光合细菌制氢技术存在的问题与应用前景。

  2. State estimation of a batch hydrogen production process using the photosynthetic bacteria Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Obeid, Jamila; Magnin, Jean-Pierre [Grenoble University, LEPMI, UMR 5631 (CNRS-INPG-UJF), Laboratoire d' Electrochimie et de Physico chimie des Materiaux et Interfaces, BP 75, 38402 St. Martin d' Heres (France); Flaus, Jean-Marie; Adrot, Olivier [Grenoble University, G-SCOP UMR 272 (CNRS-INPG-UJF), Laboratoire des Sciences pour la Conception, l' Optimisation et la Production, 46, avenue Felix Viallet, 38031 Grenoble (France); Willison, John C. [Laboratoire de Chimie et Biologie des Metaux (UMR 5249 CEA-CNRS-UJF), iRTSV/LCBM, CEA-Grenoble, 38054 Grenoble (France)

    2010-10-15

    This paper addresses the problem of estimating the states of an anaerobic photosynthetic process used for biohydrogen production by the photosynthetic bacterium Rhodobacter capsulatus. The process is described by a non-linear, time-discrete model and the state estimation is solved using an observer based on the Moving-Horizon State Estimation Method (MHSE). This approach is based on the minimization of a criterion (a non-linear function), in this case, the difference between the estimated output and the measured output of the system over a considered time horizon, where the solution is computed by using a numerical interval method. The observer was successfully applied to hydrogen production by R. capsulatus strain B10 in a batch process. (author)

  3. Enrichments for phototrophic bacteria and characterization by morphology and pigment analysis

    Science.gov (United States)

    Brune, D.

    1985-01-01

    The purpose of this investigation was to examine several sulfide containing environments for the presence of phototrophic bacteria and to obtain enriched cultures of some of the bacteria present. The field sites were Alum Rock State Park, the Palo Alto salt marsh, the bay area salt ponds, and Big Soda Lake (near Fallon, Nevada). Bacteria from these sites were characterized by microscopic examination, measurement of in vitro absorption spectra, and analysis of carotenoid pigments. Field observations at one of the bay area salt ponds, in which the salt concentration was saturating (about 30 percent NaCl) and the sediments along the shore of the pond covered with a gypsum crust, revealed a layer of purple photosynthetic bacteria under a green layer in the gypsum crust. Samples of this gypsum crust were taken to the laboratory to measure light transmission through the crust and to try to identify the purple photosynthetic bacteria present in this extremely saline environment.

  4. Communication: Coherences observed in vivo in photosynthetic bacteria using two-dimensional electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dahlberg, Peter D. [Graduate Program in the Biophysical Sciences, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States); Norris, Graham J.; Wang, Cheng; Viswanathan, Subha; Singh, Ved P.; Engel, Gregory S., E-mail: gsengel@uchicago.edu [Department of Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States)

    2015-09-14

    Energy transfer through large disordered antenna networks in photosynthetic organisms can occur with a quantum efficiency of nearly 100%. This energy transfer is facilitated by the electronic structure of the photosynthetic antennae as well as interactions between electronic states and the surrounding environment. Coherences in time-domain spectroscopy provide a fine probe of how a system interacts with its surroundings. In two-dimensional electronic spectroscopy, coherences can appear on both the ground and excited state surfaces revealing detailed information regarding electronic structure, system-bath coupling, energy transfer, and energetic coupling in complex chemical systems. Numerous studies have revealed coherences in isolated photosynthetic pigment-protein complexes, but these coherences have not been observed in vivo due to the small amplitude of these signals and the intense scatter from whole cells. Here, we present data acquired using ultrafast video-acquisition gradient-assisted photon echo spectroscopy to observe quantum beating signals from coherences in vivo. Experiments were conducted on isolated light harvesting complex II (LH2) from Rhodobacter sphaeroides, whole cells of R. sphaeroides, and whole cells of R. sphaeroides grown in 30% deuterated media. A vibronic coherence was observed following laser excitation at ambient temperature between the B850 and the B850{sup ∗} states of LH2 in each of the 3 samples with a lifetime of ∼40-60 fs.

  5. Communication: Coherences observed in vivo in photosynthetic bacteria using two-dimensional electronic spectroscopy

    Science.gov (United States)

    Dahlberg, Peter D.; Norris, Graham J.; Wang, Cheng; Viswanathan, Subha; Singh, Ved P.; Engel, Gregory S.

    2015-01-01

    Energy transfer through large disordered antenna networks in photosynthetic organisms can occur with a quantum efficiency of nearly 100%. This energy transfer is facilitated by the electronic structure of the photosynthetic antennae as well as interactions between electronic states and the surrounding environment. Coherences in time-domain spectroscopy provide a fine probe of how a system interacts with its surroundings. In two-dimensional electronic spectroscopy, coherences can appear on both the ground and excited state surfaces revealing detailed information regarding electronic structure, system-bath coupling, energy transfer, and energetic coupling in complex chemical systems. Numerous studies have revealed coherences in isolated photosynthetic pigment-protein complexes, but these coherences have not been observed in vivo due to the small amplitude of these signals and the intense scatter from whole cells. Here, we present data acquired using ultrafast video-acquisition gradient-assisted photon echo spectroscopy to observe quantum beating signals from coherences in vivo. Experiments were conducted on isolated light harvesting complex II (LH2) from Rhodobacter sphaeroides, whole cells of R. sphaeroides, and whole cells of R. sphaeroides grown in 30% deuterated media. A vibronic coherence was observed following laser excitation at ambient temperature between the B850 and the B850∗ states of LH2 in each of the 3 samples with a lifetime of ∼40-60 fs. PMID:26373989

  6. Modeling the globally-integrated spectral variability of the Archean Earth: The purple planet

    Science.gov (United States)

    Palle, E.; Sanroma, E.; Parenteau, M. N.; Kiang, N. Y.; Gutierrez-Navarro, A. M.; Lopez, R.; Montañes-Rodríguez, P.

    2014-03-01

    Ongoing searches for exoplanetary systems have revealed a wealth of planets with diverse physical properties. Planets even smaller than the Earth have already been detected and the efforts of future missions are aimed at the discovery, and perhaps characterization, of small rocky exoplanets within the habitable zone of their stars. Clearly, what we know about our planet will be our guideline for the characterization of such planets. But the Earth has been inhabited for at least 3.8 Gyr and its appearance has changed with time. Here, we have studied the Earth during the Archean eon, 3 Gyr ago. At that time, one of the more widespread life forms on the planet were purple bacteria. These bacteria are photosynthetic microorganisms and can inhabit both aquatic and terrestrial environments. Here, we use a radiative transfer model to simulate the visible and near-infrared radiation reflected by our planet, taking into account several scenarios regarding the possible distribution of purple bacteria over continents and oceans. We find that purple bacteria have a reflectance spectrum that has a strong reflectivity increase, similar to the red edge of leafy plants, although shifted redward. This feature produces a detectable signal in the disk-averaged spectra of our planet, depending on cloud amount and bacteria concentration/ distribution. We conclude that by using multi-color photometric observations, it is possible to distinguish between an Archean Earth in which purple bacteria inhabit vast extensions of the planet and a present-day Earth with continents covered by deserts, vegetation, or microbial mats.

  7. Identification of a fourth family of lycopene cyclases in photosynthetic bacteria

    OpenAIRE

    Maresca, Julia A.; Graham, Joel E.; Wu, Martin; Eisen, Jonathan A; Bryant, Donald A.

    2007-01-01

    A fourth and large family of lycopene cyclases was identified in photosynthetic prokaryotes. The first member of this family, encoded by the cruA gene of the green sulfur bacterium Chlorobium tepidum, was identified in a complementation assay with a lycopene-producing strain of Escherichia coli. Orthologs of cruA are found in all available green sulfur bacterial genomes and in all cyanobacterial genomes that lack genes encoding CrtL- or CrtY-type lycopene cyclases. The cyanobacterium Synechoc...

  8. Biohydrogen production by isolated halotolerant photosynthetic bacteria using long-wavelength light-emitting diode (LW-LED)

    Energy Technology Data Exchange (ETDEWEB)

    Kawagoshi, Yasunori; Oki, Yukinori; Nakano, Issei; Fujimoto, Aya [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Takahashi, Hirokazu [Environmental Business DivisionDaiki Ataka Engineering Co. Ltd., 2-1-9 Nishiku-Urihori, Osaka 550-0012 (Japan)

    2010-12-15

    Biohydrogen is expected as one of the alternative energy to fossil fuel. In this study, halotolerant photosynthetic hydrogen producing bacteria (ht-PHB) were isolated from a sediment of tideland, and hydrogen gas (H{sub 2}) production by isolated ht-PHB from mixed short-chain fatty acids (SFAs) using a long-wavelength light emitting diode (LW-LED) was investigated. The isolated ht-PHB grow on a culture containing three kinds of SFAs (lactic acid, acetic acid, butyric acid) and produced H{sub 2} with their complete consumption at NaCl concentration in the 0-3% range in the light of tungsten lamp. The isolated ht-PHB was phylogenetically identified as Rhodobacter sp. KUPB1. The KUPB1 showed well growth and H{sub 2} production even under LW-LED light irradiation, indicating that LW-LED is quite useful as an energy-saving light source for photosynthetic H{sub 2} production. (author)

  9. Nonphotochemical Hole-Burning Studies of Energy Transfer Dynamics in Antenna Complexes of Photosynthetic Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Satoshi Matsuzaki

    2002-08-01

    This thesis contains the candidate's original work on excitonic structure and energy transfer dynamics of two bacterial antenna complexes as studied using spectral hole-burning spectroscopy. The general introduction is divided into two chapters (1 and 2). Chapter 1 provides background material on photosynthesis and bacterial antenna complexes with emphasis on the two bacterial antenna systems related to the thesis research. Chapter 2 reviews the underlying principles and mechanism of persistent nonphotochemical hole-burning (NPHB) spectroscopy. Relevant energy transfer theories are also discussed. Chapters 3 and 4 are papers by the candidate that have been published. Chapter 3 describes the application of NPHB spectroscopy to the Fenna-Matthews-Olson (FMO) complex from the green sulfur bacterium Prosthecochloris aestuarii; emphasis is on determination of the low energy vibrational structure that is important for understanding the energy transfer process associated within three lowest energy Qy-states of the complex. The results are compared with those obtained earlier on the FMO complex from Chlorobium tepidum. In Chapter 4, the energy transfer dynamics of the B800 molecules of intact LH2 and B800-deficient LH2 complexes of the purple bacterium Rhodopseudomonas acidophila are compared. New insights on the additional decay channel of the B800 ring of bacteriochlorophyll a (BChl a) molecules are provided. General conclusions are given in Chapter 5.

  10. Separation of bacteriochlorophyll homologues from green photosynthetic sulfur bacteria by reversed-phase HPLC.

    Science.gov (United States)

    Borrego, C M; Garcia-Gil, L J

    1994-07-01

    A reversed-phase High Performance Liquid Cromatography (HPLC) method has been developed to accurately separate bacteriochlorophyllsc, d ande homologues in a reasonably short run time of 60 minutes. By using this method, two well-defined groups of bacteriochlorophyll homologue peaks can be discriminated. The first one consists of 4 peaks (min 24 to 30), which corresponds to the four main farnesyl homologues. The second peak subset is formed by a cluster of up to 10 minor peaks (min 33 to 40). These peaks can be related with series of several alcohol esters of the different chlorosome chlorophylls. The number of homologues was, however, quite variable depending on both, the bacteriochlorophyll and the bacterial species. The method hereby described, also provides a good separation of other photosynthetic pigments, either bacterial (Bacteriochlorophylla, chlorobactene, isorenieratene and okenone) or algal ones (Chlorophylla, Pheophytina and β-carotene). A preliminary screening of the homologue composition of several green photosynthetic bacterial species and isolates, has revealed different relative quantitative patterns. These differences seem to be related to physiological aspects rather than to taxonomic ones. The application of the method to the study of natural populations avoids the typical drawbacks on the pigment identification of overlapping eukaryotic and prokaryotic phototrophic microorganisms, giving further information about their physiological status.

  11. Isolation of aerobic anoxygenic photosynthetic bacteria from black smoker plume waters of the juan de fuca ridge in the pacific ocean.

    Science.gov (United States)

    Yurkov, V; Beatty, J T

    1998-01-01

    A strain of the aerobic anoxygenic photosynthetic bacteria was isolated from a deep-ocean hydrothermal vent plume environment. The in vivo absorption spectra of cells indicate the presence of bacteriochlorophyll a incorporated into light-harvesting complex I and a reaction center. The general morphological and physiological characteristics of this new isolate are described.

  12. Nonphotochemical Hole-Burning Studies of Energy Transfer Dynamics in Antenna Complexes of Photosynthetic Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Matsuzaki, Satoshi [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    This thesis contains the candidate's original work on excitonic structure and energy transfer dynamics of two bacterial antenna complexes as studied using spectral hole-burning spectroscopy. The general introduction is divided into two chapters (1 and 2). Chapter 1 provides background material on photosynthesis and bacterial antenna complexes with emphasis on the two bacterial antenna systems related to the thesis research. Chapter 2 reviews the underlying principles and mechanism of persistent nonphotochemical hole-burning (NPHB) spectroscopy. Relevant energy transfer theories are also discussed. Chapters 3 and 4 are papers by the candidate that have been published. Chapter 3 describes the application of NPHB spectroscopy to the Fenna-Matthews-Olson (FMO) complex from the green sulfur bacterium Prosthecochloris aestuarii; emphasis is on determination of the low energy vibrational structure that is important for understanding the energy transfer process associated within three lowest energy Qy-states of the complex. The results are compared with those obtained earlier on the FMO complex from Chlorobium tepidum. In Chapter 4, the energy transfer dynamics of the B800 molecules of intact LH2 and B800-deficient LH2 complexes of the purple bacterium Rhodopseudomonas acidophila are compared. New insights on the additional decay channel of the B800 ring of bacteriochlorophylla (BChla) molecules are provided. General conclusions are given in Chapter 5. A version of the hole spectrum simulation program written by the candidate for the FMO complex study (Chapter 3) is included as an appendix. The references for each chapter are given at the end of each chapter.

  13. Nonphotochemical Hole-Burning Studies of Energy Transfer Dynamics in Antenna Complexes of Photosynthetic Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Satoshi Matsuzaki

    2002-06-27

    This thesis contains the candidate's original work on excitonic structure and energy transfer dynamics of two bacterial antenna complexes as studied using spectral hole-burning spectroscopy. The general introduction is divided into two chapters (1 and 2). Chapter 1 provides background material on photosynthesis and bacterial antenna complexes with emphasis on the two bacterial antenna systems related to the thesis research. Chapter 2 reviews the underlying principles and mechanism of persistent nonphotochemical hole-burning (NPHB) spectroscopy. Relevant energy transfer theories are also discussed. Chapters 3 and 4 are papers by the candidate that have been published. Chapter 3 describes the application of NPHB spectroscopy to the Fenna-Matthews-Olson (FMO) complex from the green sulfur bacterium Prosthecochloris aestuarii; emphasis is on determination of the low energy vibrational structure that is important for understanding the energy transfer process associated within three lowest energy Q{sub y}-states of the complex. The results are compared with those obtained earlier on the FMO complex from Chlorobium tepidum. In Chapter 4, the energy transfer dynamics of the B800 molecules of intact LH2 and B800-deficient LH2 complexes of the purple bacterium Rhodopseudomonas acidophila are compared. New insights on the additional decay channel of the B800 ring of bacteriochlorophyll{sub a} (BChl{sub a}) molecules are provided. General conclusions are given in Chapter 5. A version of the hole spectrum simulation program written by the candidate for the FMO complex study (Chapter 3) is included as an appendix. The references for each chapter are given at the end of each chapter.

  14. Rapid redox signal transmission by "Cable Bacteria" beneath a photosynthetic biofilm

    NARCIS (Netherlands)

    Malkin, S.Y.; Meysman, F.J.R.

    2015-01-01

    Recently, long filamentous bacteria, belonging to the family Desulfobulbaceae, were shown to induce electrical currents over long distances in the surface layer of marine sediments. These “cable bacteria” are capable of harvesting electrons from free sulfide in deeper sediment horizons and

  15. Rapid redox signal transmission by "Cable Bacteria" beneath a photosynthetic biofilm

    NARCIS (Netherlands)

    Malkin, S.Y.; Meysman, F.J.R.

    2015-01-01

    Recently, long filamentous bacteria, belonging to the family Desulfobulbaceae, were shown to induce electrical currents over long distances in the surface layer of marine sediments. These “cable bacteria” are capable of harvesting electrons from free sulfide in deeper sediment horizons and transferr

  16. Calvin cycle mutants of photoheterotrophic purple nonsulfur bacteria fail to grow due to an electron imbalance rather than toxic metabolite accumulation.

    Science.gov (United States)

    Gordon, Gina C; McKinlay, James B

    2014-03-01

    Purple nonsulfur bacteria grow photoheterotrophically by using light for energy and organic compounds for carbon and electrons. Disrupting the activity of the CO2-fixing Calvin cycle enzyme, ribulose 1,5-bisphosphate carboxylase (RubisCO), prevents photoheterotrophic growth unless an electron acceptor is provided or if cells can dispose of electrons as H2. Such observations led to the long-standing model wherein the Calvin cycle is necessary during photoheterotrophic growth to maintain a pool of oxidized electron carriers. This model was recently challenged with an alternative model wherein disrupting RubisCO activity prevents photoheterotrophic growth due to the accumulation of toxic ribulose-1,5-bisphosphate (RuBP) (D. Wang, Y. Zhang, E. L. Pohlmann, J. Li, and G. P. Roberts, J. Bacteriol. 193:3293-3303, 2011, http://dx.doi.org/10.1128/JB.00265-11). Here, we confirm that RuBP accumulation can impede the growth of Rhodospirillum rubrum (Rs. rubrum) and Rhodopseudomonas palustris (Rp. palustris) RubisCO-deficient (ΔRubisCO) mutants under conditions where electron carrier oxidation is coupled to H2 production. However, we also demonstrate that Rs. rubrum and Rp. palustris Calvin cycle phosphoribulokinase mutants that cannot produce RuBP cannot grow photoheterotrophically on succinate unless an electron acceptor is provided or H2 production is permitted. Thus, the Calvin cycle is still needed to oxidize electron carriers even in the absence of toxic RuBP. Surprisingly, Calvin cycle mutants of Rs. rubrum, but not of Rp. palustris, grew photoheterotrophically on malate without electron acceptors or H2 production. The mechanism by which Rs. rubrum grows under these conditions remains to be elucidated.

  17. 近红外光源对光合细菌生长的影响%Influence of near-infrared on growth of photosynthetic bacteria

    Institute of Scientific and Technical Information of China (English)

    李家洲; 张冬青; 黄荣林; 赵鑫; 肖玉平

    2012-01-01

    光合细菌的光合色素能吸收近红外光进行光合作用.利用加可见光滤光镜的卤钨灯作为近红外光源,照射光合细菌,探讨其对光合细菌生长的影响.结果表明,相对于可见光,近红外光对光合细菌的生长有明显促进作用,可使最大菌体浓度提高45%以上.近红外光照强度饱和区为20W~35W之间,低于20W时,光合细菌的生长速率随光照强度升高而升高;超过50W后,近红外光对光合细菌产生抑制作用.温度和pH值2个培养参数对近红外光的光照效果没有明显的影响.%The photosynthetic pigments can absorb near-infrared lights for photosynthesis. Halogen tungsten lamp filtered with visible-light filter lens as light source, influence of photosynthetic bacteria growth was researched. The results were as follows: compared with visible-light, near-infrared lights can promote photosynthetic bacteria growth markedly and can increase the max cell concentration about 45%; the region of near-infrared light saturation was between 20W to 35W; when lower than 20W, growth rate of photosynthetic bacteria increased with light intensity increasing; when higher than 50W, near-infrared light could inhibit photosynthetic bacteria growth. The temperature and pH value had no influence on the near-infrared light effect.

  18. Probing the effect of the binding site on the electrostatic behavior of a series of carotenoids reconstituted into the light-harvesting 1 complex from purple photosynthetic bacterium Rhodospirillum rubrum detected by stark spectroscopy.

    Science.gov (United States)

    Nakagawa, Katsunori; Suzuki, Satoru; Fujii, Ritsuko; Gardiner, Alastair T; Cogdell, Richard J; Nango, Mamoru; Hashimoto, Hideki

    2008-08-01

    Reconstitutions of the LH1 complexes from the purple photosynthetic bacterium Rhodospirillum rubrum S1 were performed with a range of carotenoid molecules having different numbers of C=C conjugated double bonds. Since, as we showed previously, some of the added carotenoids tended to aggregate and then to remain with the reconstituted LH1 complexes (Nakagawa, K.; Suzuki, S.; Fujii, R.; Gardiner, A.T.; Cogdell, R.J.; Nango, M.; Hashimoto, H. Photosynth. Res. 2008, 95, 339-344), a further purification step using a sucrose density gradient centrifugation was introduced to improve purity of the final reconstituted sample. The measured absorption, fluorescence-excitation, and Stark spectra of the LH1 complex reconstituted with spirilloxanthin were identical with those obtained with the native, spirilloxanthin-containing, LH1 complex of Rs. rubrum S1. This shows that the electrostatic environments surrounding the carotenoid and bacteriochlorophyll a (BChl a) molecules in both of these LH1 complexes were essentially the same. In the LH1 complexes reconstituted with either rhodopin or spheroidene, however, the wavelength maximum at the BChl a Qy absorption band was slightly different to that of the native LH1 complexes. These differences in the transition energy of the BChl a Qy absorption band can be explained using the values of the nonlinear optical parameters of this absorption band, i.e., the polarizability change Tr(Deltaalpha) and the static dipole-moment change |Deltamu| upon photoexcitation, as determined using Stark spectroscopy. The local electric field around the BChl a in the native LH1 complex (ES) was determined to be approximately 3.0x10(6) V/cm. Furthermore, on the basis of the values of the nonlinear optical parameters of the carotenoids in the reconstituted LH1 complexes, it is possible to suggest that the conformations of carotenoids, anhydrorhodovibrin and spheroidene, in the LH1 complex were similar to that of rhodopin glucoside in crystal structure of

  19. Effects of dissolved oxygen concentration on photosynthetic bacteria wastewater treatment: Pollutants removal, cell growth and pigments production.

    Science.gov (United States)

    Meng, Fan; Yang, Anqi; Zhang, Guangming; Wang, Hangyao

    2017-10-01

    Dissolved oxygen (DO) is an important parameter in photosynthetic bacteria (PSB) wastewater treatment. This study set different DO levels and detected the pollutants removal, PSB growth and pigments production. Results showed that DO significantly influenced the performances of PSB wastewater treatment process. The highest COD (93%) and NH3-N removal (83%) was achieved under DO of 4-8mg/L, but DO of 2-4mg/L was recommended considering the aeration cost. PSB biomass reached 1645mg/L under DO of 4-8mg/L with satisfying co-enzyme Q10 content. The biomass yield was relatively stable at all DO levels. For bacteriochlorophyll and carotenoids, DO>1mg/L could satisfy their production. On the other hand, DO<0.5mg/L led to the highest dehydrogenase activity. According to the different purposes, the optimal treatment time was different. The most pigments production occurred at 24h; biomass reached peak at 48h; and the optimal time for pollutants removal was 72h. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Biomass recovery during municipal wastewater treatment using photosynthetic bacteria and prospect of production of single cell protein for feedstuff.

    Science.gov (United States)

    Saejung, Chewapat; Thammaratana, Thani

    2016-12-01

    Utilization of photosynthetic bacteria (PSB) for wastewater treatment and production of biomass for economical single cell protein production is a feasible option. In this study, Rhodopseudomonas sp. CSK01 was used for municipal wastewater treatment and the effect of initial pH, light intensity and additional carbon source was investigated. Optimum chemical oxygen demand (COD) removal and biomass production were achieved when the initial pH and light intensity were 7 and 4000 lux, respectively. The specific growth rate, biomass yield and biomass productivity were found to be 0.4/d, 3.2 g/g COD and 2.1 g/L/d, respectively, which were improved by 100%, 167% and 200% relative to the original condition. Under the optimal conditions, COD removal reached 85% and maximum biomass was 6.2 g/L accomplished within three days of cultivation. The biomass had a relatively high protein content (60.1%) consisting of all essential amino acids. The contents of histidine, lysine, phenylalanine and leucine were superior to those of the previously described PSB. Results showed that COD removal was not improved in the presence of additional carbon sources (glucose, sucrose and malic acid). The addition of malic acid significantly increased the biomass accumulation by 279% relative to the original condition, whereas COD removal was declined due to carbon catabolite repression. In this study, PSB biomass recovery and catabolite repression are proposed in municipal wastewater treatment by Rhodopseudomonas sp.

  1. Hydrogen production by photosynthetic bacteria Rhodobacter capsulatus Hup{sup -} strain on acetate in continuous panel photobioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Deo Androga, Dominic; Ozgur, Ebru; Eroglu, Inci [Middle East Technical Univ., Ankara (Turkey). Dept. of Chemical Engineering; Guenduez, Ufuk [Middle East Technical Univ., Ankara (Turkey). Dept. of Biology

    2010-07-01

    Photobiological hydrogen production from organic acids occurs in the presence of light and under anaerobic conditions. Stable and optimized operation of the photobioreactors is the most challenging task in the photofermentation process. The aim of this study was to achieve a stable and high hydrogen production on acetate, using the photosynthetic bacteria Rhodobacter capsulatus Hup{sup -} (uptake hydrogenase deleted strain) in continuous panel photobioreactors. An indoor experiment with continuous illumination (1500-2500 lux, corresponding to 101-169 W/m{sup 2}) and controlled temperature was carried out in a 8 L panel photobioreactor. A modified form of basal culture media containing 40 mM of acetate and 2 mM of glutamate with a feeding rate of 0.8 L/day was used. Stable hydrogen productivity of 0.7 mmol H{sub 2}/l{sub c}.h was obtained, however, biomass decreased during the continuous operation. Further indoor experiments with a biomass recycle and different feed compositions were carried out to optimise the feed composition for a stable biomass and hydrogen production. The highest hydrogen productivity of 0.8 mmol H{sub 2}/l{sub c}.h and yield of 88% was obtained in the 40 mM/ 4 mM acetate/glutamate continuously fed photobioreactor for a period of 21 days. (orig.)

  2. Role of an elliptical structure in photosynthetic energy transfer: Collaboration between quantum entanglement and thermal fluctuation.

    Science.gov (United States)

    Oka, Hisaki

    2016-05-13

    Recent experiments have revealed that the light-harvesting complex 1 (LH1) in purple photosynthetic bacteria has an elliptical structure. Generally, symmetry lowering in a structure leads to a decrease in quantum effects (quantum coherence and entanglement), which have recently been considered to play a role in photosynthetic energy transfer, and hence, elliptical structure seems to work against efficient photosynthetic energy transfer. Here we analyse the effect of an elliptical structure on energy transfer in a purple photosynthetic bacterium and reveal that the elliptical distortion rather enhances energy transfer from peripheral LH2 to LH1 at room temperature. Numerical results show that quantum entanglement between LH1 and LH2 is formed over a wider range of high energy levels than would have been the case with circular LH1. Light energy absorbed by LH2 is thermally pumped via thermal fluctuation and is effectively transferred to LH1 through the entangled states at room temperature rather than at low temperature. This result indicates the possibility that photosynthetic systems adopt an elliptical structure to effectively utilise both quantum entanglement and thermal fluctuation at physiological temperature.

  3. Methods to measure biomass and production of bacteria and photosynthetic microbiota and their application on illuminated lake sediments. A literature study

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Eva [Uppsala Univ. (Sweden). Dept. of Limnology

    2001-06-01

    In the work of finding a place for long time storage of radioactive waste it is of importance to understand the surrounding ecosystems. The storage is supposed to keep the radioactive waste away from humans and nature for some hundreds of thousands of years. It is important to be able to make risk assessments for a hypothetical release and understand by which ways the radionuclides could find their way into the biota. In lakes, released radionuclides would most probably find their way into the biota through heterotrophic bacteria or auto trophic microorganisms. Therefore, it is important to investigate how large the biomass and production of heterotrophic bacteria and photosynthetic organisms in lakes are. This report is an overview of methods that are commonly used today for measuring biomass and production of bacteria and photosynthetic microorganisms in lakes. It elucidates advantages and drawbacks of the different methods. Some results from studies on illuminated lake sediment habitats are given. Biomass of bacteria is commonly measured in microscope after colouring the bacteria with a dye. Dyes commonly used are acridine orange and 4',6-diamino-2-phenylindole (DAPI). Biomass of photosynthetic microorganisms is also commonly measured in microscope but can also be determined by the amount of chlorophyll 'a' and other pigments. An advantage with measuring the biomass photosynthetic microorganisms in microscope is that a good resolution of the community is achieved. A disadvantage with determining the biomass by measuring the chlorophyll 'a' concentrations is that the concentrations may vary with light climate and nutrients even though the carbon biomass is constant. Methods for measuring bacterial production discussed in this report are the thymidine incorporation method, the leucine incorporation method and the frequency of dividing cell method (FDC). Methods for primary production discussed in this report are the {sup 14}CO{sub 2

  4. 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.

  5. 紫细菌光合色素指纹图谱的建立与色素分析%Fingerprinting analysis of photopigments in purple bacteria

    Institute of Scientific and Technical Information of China (English)

    卓民权; 赵春贵; 程茜茹; 杨素萍; 曲音波

    2012-01-01

    [Objective] Photopigments, including carotenoid and bacteriochlorophyll a, are the most important functional units of photosynthesis in purple bacteria. We developed rapid qualitative and quantitative methods to determine photopigments. [Methods] Using Rhodopesudomonas palustris CQV97 as a reference, we used image gray intensity analysis, absorption spectrophotometry, thin layer chromatography (TLC) , HPLC and mass spectrometry (MS) for photopigment analysis. [Results] The total amount of photopigments increased by 13.5% by using modified acetone-methanol extraction. We developed two types of photopigment fingerprintings by TLC and HPLC, estimated the apparent relative content of each photopigment of fingerprintings, and determined the corresponding relationships between Rf value of each photopigment on TLC fingerprinting and retention time of each photopigment elution in HPLC fingerprinting. Based on the data from the absorption spectra, MS and related photopigment biosynthetic pathway analysis, we identified 11 photopigments in CQY97 strain. Using this strain as a standard, we analyzed photopigments of the tested samples by TLC or HPLC. It was shown that (1) the relative standard deviation (RSD) of the two methods was less than 5% ; (2) the compositions and contents of the theory sample were consistent with that of the standard sample; (3) the photopigment compositions of the real sample was the same as the standard sample, but the photopigment content was different. [Conclusion] Both of TLC and HPLC analyses for photopigment determination have good stability and repeatability. The fingerprintings analyses are suitable for rapid determination of photopigments of purple bacteria and have important application in control of regulation mechanism for photopigment synthesis.%[目的]探索快速高效的色素样品制备方法;为建立紫细菌全色素TLC和HPLC标准指纹图谱和数据库提供研究方法和思路;为色素代谢与调控等研究提供快

  6. Sulfur metabolism in phototrophic sulfur bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Dahl, Christiane

    2008-01-01

    Phototrophic sulfur bacteria are characterized by oxidizing various inorganic sulfur compounds for use as electron donors in carbon dioxide fixation during anoxygenic photosynthetic growth. These bacteria are divided into the purple sulfur bacteria (PSB) and the green sulfur bacteria (GSB......). They utilize various combinations of sulfide, elemental sulfur, and thiosulfate and sometimes also ferrous iron and hydrogen as electron donors. This review focuses on the dissimilatory and assimilatory metabolism of inorganic sulfur compounds in these bacteria and also briefly discusses these metabolisms...... in other types of anoxygenic phototrophic bacteria. The biochemistry and genetics of sulfur compound oxidation in PSB and GSB are described in detail. A variety of enzymes catalyzing sulfur oxidation reactions have been isolated from GSB and PSB (especially Allochromatium vinosum, a representative...

  7. Purple and Celie

    Institute of Scientific and Technical Information of China (English)

    官宇

    2013-01-01

    In the novel The Color Purple, purple is a color that Alice Walker uses to symbolize the main character:Celie. In col⁃or psychology, purple is a complex color. At first, it has two contradictory symbolic meanings just as Celie’s personality. Second⁃ly, purple is a color which blends blue and red. In western countries, red symbolized man and blue symbolized woman. Howev⁃er, Celie is a person who has both man’s and woman’s characteristics. At last, purple is a changeable color. Celie’s early misery life is like dark purple which has more of a passive meaning. And her later life turns out to be light purple which symbolizes more of the beautiful things. And the turning of her life may be viewed as awakening of womanism.

  8. Progresses in Application of Photosynthetic Bacteria in Environmental Remediation%光合细菌在环境修复中的研究进展

    Institute of Scientific and Technical Information of China (English)

    陈莎; 刘勇

    2012-01-01

    A photosynthetic bacterium is a class of special anaerobic microorganism which can carry on photosynthesis, and it has played a very important role in environmental remediation due to its unique physiological and biochemical characteristics. The applications of photosynthetic bacteria in the treatments for high-concentration of organic wastewater, soil heavy metal contamination, degradation of organophosphorus pesticide, etc. in recent years were reviewed. In the end, the application prospect and developmental direction of photosynthetic bacteria in environmental remediation are forecasted.%光合细菌是在自然界中能进行光合作用的一类特殊厌氧微生物,其独特的生理生化特性,使得其在环境修复中发挥着十分重要的作用.对近年来光合细菌在处理高浓度有机废水、土壤重金属污染治理、有机磷农药降解及养殖水体的净化等方面的应用进行了综述,最后对光合细菌在环境修复中的应用前景和发展方向进行了展望.

  9. [Formation of 55-kDa Fragments under Impaired Coordination Bonds and Hydrophobic Interactions in Peripheral Light-Harvesting Complexes Isolated from Photosynthetic Purple Bacteria].

    Science.gov (United States)

    Solov'ev, A A; Erokhin, Y E

    2015-01-01

    Size exclusion chromatography was used to assess the relative size of intact and diphenylamine-treated (DPA, with suppressed carotenoid synthesis) peripheral light-harvesting complexes (LH2 complexes) of the sulfurbacterium Allochromatium minutissimum. Both LH2 complexes were nonamers and had the same elution volume V(e), coinciding with that for the LH2 complex of Rhodoblastus acidophilus (strain 10050). Their molecular mass was 150 kDa. Bot pheophytinization of bacteriochlorophyll (BChl) at low pH and treatment with the detergent LDAO, affecting the hydrophobic interactions between the neighboring protomers, result in the fragmentation of the ring of the isolated LH2 complexes and formation of 55-kDa fragments with molecular masses corresponding to one-third of the initial value. Fragmentation caused by both pheophytinization and detergent treatment was much more rapid in DPA-treated LH2 complexes than in the intact ones. The 55-kDa fragments formed at low pH values contained monomeric bacteriopheophytin, while the fragments of a similar molecular mass formed at pH 8.0 in the presence of the detergent contained monomeric BChl. The observed fragmentation was hypothesized to reflect the inherent C3 symmetry of the LH2 complexes, with the preliminarily assembled trimers used as building blocks.

  10. 几种植物激素对光合细菌生长的影响%Effect of Several Plant Hormones on the Growth of Photosynthetic Bacteria

    Institute of Scientific and Technical Information of China (English)

    武丽娜

    2012-01-01

    [ Objective ] To explore the effect of several plant hormones on the growth of photosynthetic bacteria, so as to provide references for studying its growth promotion factors. [Method] The influence of different concentrations of indole acetic acid, a-NAA, gibberellin and mixing plant hormone on the growth of photosynthetic bacteria was observed. [ Result ] The three kinds of plant hormones can accelerate the growth of photosynthetic bacteria. Gibberellin had the most significant growth promotion effect on the photosynthetic bacteria, then was the mixing plant hormones. The optimum concentrations of indole acetic acid, a-NAA and gibbereliin are 0.5, 5 and 0.5 mg/L respectively. [Conclusion] It is feasible to promote the growth of the photosynthelic bacteria by adding some plant hormones in enrichment cultivation.%[目的]探讨几种植物激素对光合细菌生长的影响,以期为光合细菌增殖培养的促生长因子研究提供参考依据.[方法]研究了不同浓度的吲哚乙酸、α-萘乙酸和赤霉素以及混合植物激素对光合细菌生长的影响.[结果]3种植物激素对光合细菌的生长均具有促进作用,其中赤霉素效果最为明显,其次为混合植物激素.吲哚乙酸、α-萘乙酸和赤霉素促生长的最佳浓度分别为0.5、1和0.5 mg/L.[结论]该研究结果表明在增殖培养基中加入某些植物生长激素来促进光合细菌的生长是可行的.

  11. Characterizing the purple Earth: Modelling the globally-integrated spectral variability of the Archean Earth

    CERN Document Server

    Sanromá, E; Parenteau, M N; Kiang, N Y; Gutiérrez-Navarro, A M; López, R; Montañés-Rodríguez, P

    2013-01-01

    The ongoing searches for exoplanetary systems have revealed a wealth of planets with diverse physical properties. Planets even smaller than the Earth have already been detected, and the efforts of future missions are placed on the discovery, and perhaps characterization, of small rocky exoplanets within the habitable zone of their stars. Clearly what we know about our planet will be our guideline for the characterization of such planets. But the Earth has been inhabited for at least 3.8 Ga, and its appearance has changed with time. Here, we have studied the Earth during the Archean eon, 3.0 Ga ago. At that time one of the more widespread life forms on the planet were purple bacteria. These bacteria are photosynthetic microorganisms and can inhabit both aquatic and terrestrial environments. Here, we used a radiative transfer model to simulate the visible and near-IR radiation reflected by our planet, taking into account several scenarios regarding the possible distribution of purple bacteria over continents an...

  12. Self-sustaining, solar-driven bioelectricity generation in micro-sized microbial fuel cell using co-culture of heterotrophic and photosynthetic bacteria

    Science.gov (United States)

    Liu, Lin; Choi, Seokheun

    2017-04-01

    Among many energy harvesting techniques with great potential, microbial fuel cell (MFC) technology is arguably the most underdeveloped. Even so, excitement is building, as microorganisms can harvest electrical power from any biodegradable organic source (e.g. wastewater) that is readily available in resource-limited settings. Nevertheless, the requirement for endless introduction of organic matter imposes a limiting factor to this technology, demanding an active feeding system and additional power. Here, we demonstrated self-sustaining bioelectricity generation from a microliter-scale microbial fuel cell (MFC) by using the syntrophic interaction between heterotrophic exoelectrogenic bacteria and phototrophs. The MFC continuously generated light-responsive electricity from the heterotrophic bacterial metabolic respiration with the organic substrates produced by photosynthetic bacteria. Without additional organic fuel, the mixed culture in a 90-μL-chamber MFC generated self-sustained current for more than 13 days, while the heterotrophic culture produced current that decreased dramatically within a few hours. The current from the mixed culture was about 70 times greater than that of the device with only photosynthetic bacteria. The miniaturization provided a short start-up time, a well-controlled environment, and small internal resistance. Those advantages will become the general design platform for micropower generation.

  13. Spectroscopic Studies of Photosynthetic Systems and Their Application in Photovoltaic Devices - Equipment Only: Cooperative Research and Development Final Report, CRADA Number CRD-06-175

    Energy Technology Data Exchange (ETDEWEB)

    Seibert, M.

    2014-09-01

    Spectral hole-burning (SHB) and single photosynthetic complex spectroscopy (SPCS) will be used to study the excitonic structure and excitation energy transfer (EET) processes of several photosynthetic protein complexes at low temperatures. The combination of SHB on bulk samples and SPCS is a powerful frequency domain approach for obtaining data that will address a number of issues that are key to understanding excitonic structure and energy transfer dynamics. The long-term goal is to reach a better understanding of the ultrafast solar energy driven primary events of photosynthesis as they occur in higher plants, cyanobacteria, purple bacteria, and green algae. A better understanding of the EET and charge separation (CS) processes taking place in photosynthetic complexes is of great interest, since photosynthetic complexes might offer attractive architectures for a future generation of circuitry in which proteins are crystallized.

  14. Experimental Study on Characteristics of Photosynthetic Bacteria in Continuously Hydrogen Production Reactor%连续制氢反应器中光合细菌特性试验研究

    Institute of Scientific and Technical Information of China (English)

    李亚丽

    2011-01-01

    [Objective] The study was to lay a foundation for the industrialization development of hydrogen production with photosynthetic bacteria. [Method] With the mixed bacteria of photosynthetic bacteria as the tested strains, the concentration change, hydrogen producing characteristics of the photosynthetic bacteria and the relationship between bacteria number and hydrogen yield were studied. [ Result] The photosynthetic bacteria concentration and hydrogen yield in the 2#, 3# compartment of continuously hydrogen production reactor was the most. In the same compartment, the photosynthetic bacteria concentration and hydrogen yield on the 2nd, 3rd d was the most. [Conclusion] The hydrogen yield of photosynthetic bacteria in reactor was reduced with the reduction of its concentration.%[目的]为光合细菌制氢的工业化发展奠定基础.[方法]以光合细菌混合菌群为试验菌种,研究其在连续制氢反应器中的浓度变化、产氢特性及细菌数量与产氢量的关系.[结果]连续制氢反应器的2#、3#隔室光合细菌浓度最大,产氢量也最大.同一隔室内,第2、3d光合细菌浓度和产氢量均达到最大.[结论]产氢量随反应器中光合细菌数量的减少而减少.

  15. Purple urine bag syndrome- changing hue!

    Directory of Open Access Journals (Sweden)

    Sadhna Sharma

    2013-02-01

    Full Text Available Purple Urine Bag Syndrome (PUBS is a unique disease entity characterised by purple discoloration of urine secondary to recurrent urinary tract infections with indigo and indirubin producing bacteria and is predominantly seen in constipated, chronically debilitated and catheterised women with alkaline urine. This syndrome indicates underlying recurrent urinary tract infections (UTIs associated with higher incidence of mortality and morbidity than urinary tract infection alone without this occurrence. This article is about an elderly hypothyroid woman with PUBS and reviews the need to be aware of this entity. [Int J Res Med Sci 2013; 1(1.000: 31-32

  16. 光合细菌对苗期水稻抗氧化作用的影响%Effect of Photosynthetic Bacteria on Rice Seedling Antioxidant Function

    Institute of Scientific and Technical Information of China (English)

    王秋菊

    2009-01-01

    The effect of photosynthetic bacteria on rice pigment and antioxidant enzyme systems was studied which irradiated by ultraviolet.The results showed that catalase(CAT),superoxide dismutase(SOD),the chlorophyll content had change after ultraviolet radiation,the ultraviolet radiation had the induce function on rice catalase,superoxide dismutase activity and chlorophyll content,while photosynthetic bacteria played protective role on rice in the ultraviolet radiation.%光合细菌施用于水稻,经紫外线照射后对水稻色素及抗氧化酶系统的影响进行了研究.结果表明,经紫外线照射后的水稻过氧化氢酶、超氧化物歧化酶、叶绿素含量发生变化,紫外线辐射对水稻的过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性及叶绿素含量均有诱导作用,而光合细菌对水稻

  17. APPLY STUDU ON PHOTOSYNTHETIC BACTERIA IN OVERWINTERING POND%光合细菌在越冬池中的应用研究

    Institute of Scientific and Technical Information of China (English)

    李池陶; 王梅生; 白庆利; 石连玉

    2000-01-01

    By applying photosynthetic bacteria under the ice of overwintering pond,the experiment about the effect on fishes in winter was carried out in Minfu fishery base of Heilongjiang viver Research Institate.By analyzing water quality regulary and commparing the overwintenig Survival rate,the resules showsthat The fluctuattion of dissowed oxygen and the biomass of plandto under the ice of overwintering jpond in witer by applying photosynthetic bacteria is very little,and water quality is also cleaned,physical and chemical factos in overwinterig waters remain steble,which make fishes live through the winter safely.%在黑龙江水产研究所民富鱼类培育中心进行了越冬池冰下施光合细菌对鱼类越冬影响的试验。经过水质定期分析及越冬成活率的比较,得出越冬池施光合细菌能使越冬池冰下水体中溶解氧和浮游植物生物量的波动较小,净化越冬池水质,使越冬水体各理化因子处于较稳定的状态,从而保证鱼类安全过冬。

  18. Simultaneous photocatalytic and microbial degradation of dye-containing wastewater by a novel g-C3N4-P25/photosynthetic bacteria composite

    Science.gov (United States)

    Zhang, Xinying; Wu, Yan; Xiao, Gao; Tang, Zhenping; Wang, Meiyin; Liu, Fuchang; Zhu, Xuefeng

    2017-01-01

    Azo dyes are very resistant to light-induced fading and biodegradation. Existing advanced oxidative pre-treatment methods based on the generation of non-selective radicals cannot efficiently remove these dyes from wastewater streams, and post-treatment oxidative dye removal is problematic because it may leave many byproducts with unknown toxicity profiles in the outgoing water, or cause expensive complete mineralization. These problems could potentially be overcome by combining photocatalysis and biodegradation. A novel visible-light-responsive hybrid dye removal agent featuring both photocatalysts (g-C3N4-P25) and photosynthetic bacteria encapsulated in calcium alginate beads was prepared by self-assembly. This system achieved a removal efficiency of 94% for the dye reactive brilliant red X-3b and also reduced the COD of synthetic wastewater samples by 84.7%, successfully decolorized synthetic dye-contaminated wastewater and reduced its COD, demonstrating the advantages of combining photocatalysis and biocatalysis for wastewater purification. The composite apparently degrades X-3b by initially converting the dye into aniline and phenol derivatives whose aryl moieties are then attacked by free radicals to form alkyl derivatives, preventing the accumulation of aromatic hydrocarbons that might suppress microbial activity. These alkyl intermediates are finally degraded by the photosynthetic bacteria. PMID:28273118

  19. Energy transfer pathways in light-harvesting complexes of purple bacteria as revealed by global kinetic analysis of two-dimensional transient spectra.

    Science.gov (United States)

    Ostroumov, Evgeny E; Mulvaney, Rachel M; Anna, Jessica M; Cogdell, Richard J; Scholes, Gregory D

    2013-09-26

    Excited state dynamics in LH2 complexes of two purple bacterial species were studied by broad-band two-dimensional electronic spectroscopy. The optical response was measured in the 500-600 nm spectral region on the 0-400 fs time scale. Global target analysis of two-dimensional (2D) transient spectra revealed the main energy transfer pathways between carotenoid S2, 1Bu(-) and S1 states and bacteriochlorophyll Qx state. Global analysis ascertained the evolutionary and vibration-associated spectra, which also indicated the presence of a higher-lying vibrational level in the carotenoid S1 state. The estimation of the spectral overlap between the 1Bu(-) state and the Qx state indicated a significant contribution of the 1Bu(-) state to the overall S2-to-Qx excitation energy transfer.

  20. Forster Energy Transfer Theory as Reflected in the Structures of Photosynthetic Light-Harvesting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Sener, Melih [Univ. of Illinois, Urbana-Champaign, IL (United States); Strumpfer, Johan [Univ. of Illinois, Urbana-Champaign, IL (United States); Hsin, Jen [Univ. of Illinois, Urbana-Champaign, IL (United States); Chandler, Danielle [Univ. of Illinois, Urbana-Champaign, IL (United States); Scheuring, Simon [Institut National de la Sante Et Recherche Medicale, Paris (France); Hunter, C. Neil [Univ. of Sheffield (United Kingdom); Schulten, Klaus [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2011-02-22

    Förster's theory of resonant energy transfer underlies a fundamental process in nature, namely the harvesting of sunlight by photosynthetic life forms. The theoretical framework developed by Förster and others describes how electronic excitation migrates in the photosynthetic apparatus of plants, algae, and bacteria from light absorbing pigments to reaction centers where light energy is utilized for the eventual conversion into chemical energy. The demand for highest possible efficiency of light harvesting appears to have shaped the evolution of photosynthetic species from bacteria to plants which, despite a great variation in architecture, display common structural themes founded on the quantum physics of energy transfer as described first by Förster. Herein, Förster’s theory of excitation transfer is summarized, including recent extensions, and the relevance of the theory to photosynthetic systems as evolved in purple bacteria, cyanobacteria, and plants is demonstrated. Förster's energy transfer formula, as used widely today in many fields of science, is also derived.

  1. An update on purple urine bag syndrome

    Directory of Open Access Journals (Sweden)

    Hadano Y

    2012-08-01

    Full Text Available Yoshiro Hadano,1 Taro Shimizu,2 Shimon Takada,3 Toshiya Inoue,4 Sumire Sorano51Department of General Internal Medicine and Infectious Diseases, Rakuwakai Otowa Hospital, Yamashina-ku, Kyoto, Japan; 2Rollins School of Public Health, Emory University, Atlanta, GA, USA; 3Department of General Internal Medicine, Osaka City General Hospital, Miyakojima-ku, Osaka, Japan; 4Department of Emergency Medicine, Urasoe General Hospital, Urasoe-city, Okinawa, Japan; 5Kobe University School of Medicine, Kusunokicho, Chuoku, Kobe, JapanAbstract: Purple urine bag syndrome is characterized by the urinary drainage bag turning purple in patients on prolonged urinary catheterization, especially those in the bedridden state. It is associated with bacterial urinary tract infections caused by indigo-producing and indirubin-producing bacteria, usually affects women, and is associated with alkaline urine, constipation, and a high bacterial load in the urine. Almost all patients with purple urine bag syndrome are catheterized due to significant disability, and the urinary pH is 7.0 or more. In general, intensive treatment with antibiotics is not recommended. Purple urine bag syndrome per se almost always appears to be asymptomatic and harmless. However, caution is needed, because some cases have been reported to show progression to severe disease states, so further research into the morbidity and mortality of this infection is warranted.Keywords: purple urine, urinary catheterization, geriatrics, urinary tract infection

  2. Status of Purple Loosetrife

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A letter to the New York Cooperative Wildlife Research Unit regarding measures taken to control Purple loosestife at Parker River National Wildlife Refuge....

  3. A Rapid Method for the Extraction and Analysis of Carotenoids and Other Hydrophobic Substances Suitable for Systems Biology Studies with Photosynthetic Bacteria

    Directory of Open Access Journals (Sweden)

    Oliver Sawodny

    2013-10-01

    Full Text Available A simple, rapid, and inexpensive extraction method for carotenoids and other non-polar compounds present in phototrophic bacteria has been developed. The method, which has been extensively tested on the phototrophic purple non-sulphur bacterium Rhodospirillum rubrum, is suitable for extracting large numbers of samples, which is common in systems biology studies, and yields material suitable for subsequent analysis using HPLC and mass spectroscopy. The procedure is particularly suitable for carotenoids and other terpenoids, including quinones, bacteriochlorophyll a and bacteriopheophytin a, and is also useful for the analysis of polar phospholipids. The extraction procedure requires only a single step extraction with a hexane/methanol/water mixture, followed by HPLC using a Spherisorb C18 column, with a mobile phase consisting of acetone-water and a non-linear gradient of 50%–100% acetone. The method was employed for examining the carotenoid composition observed during microaerophilic growth of R. rubrum strains, and was able to determine 18 carotenoids, 4 isoprenoid-quinones, bacteriochlorophyll a and bacteriopheophytin a as well as four different phosphatidylglycerol species of different acyl chain compositions. The analytical procedure was used to examine the dynamics of carotenoid biosynthesis in the major and minor pathways operating simultaneously in a carotenoid biosynthesis mutant of R. rubrum.

  4. Ozone and Photosynthetic Bacteria Combined Remediation of Landscape Research%臭氧和光合细菌联合修复景观水体的研究

    Institute of Scientific and Technical Information of China (English)

    王小江; 李振轮

    2014-01-01

    Joint treatment of lands cape water body by ozone and photosynthetic bacteria was investigated. The results showed that, in the control of water for 7.5 pH, which added to the ozone 25 min (hourly produce 1.5 g), in which added to four hundreds million the photosynthetic bacteria about standing for 5 days, landscape water could get better purification effect. According to the current ozone technology, preparation of 1 kg per ozone consumption at approximately 20 kW·h, according to every 1 kg COD decomposition of ozone computing needs 3 kg, each treatment takes about 28 RMB 1kg COD. Higher operating cost is one of the main factors of large-scale application of this technology failed. But the experiment combined the use of ozone and photosynthetic bacteria landscape water treatment methods for each treatment took only about 1kg COD 16.5 RMB, significant cost savings, but also improved efficiency. Therefore, through the joint processing of ozone and photosynthetic bacteria, purify organic pollution and improve water landscape water quality. This method not only saved cost, but also achieved good results.%研究了臭氧和光合细菌联合处理景观水体,结果表明,在控制水体pH值为7.5,按照1 L样品通臭氧25 min (每h产生1.5 g)后,在向其中加入4亿个光合细菌大约静置5 d,景观污水将得到较好的净化效果。根据目前的臭氧制取技术,每制取1 kg臭氧约耗电在20 kW·h,按照每分解1 kg COD需要3 kg的臭氧计算,则每处理1 kg COD需要28元左右。较高的运行费用也是这一技术未能大规模应用的主要因素之一。但是该实验利用臭氧和光合细菌联合处理景观水的方法每处理1 kg COD只需要16.5元左右,大大节约了成本,还提高了效率。因此通过臭氧和光合细菌联合处理技术,净化景观水体中的有机物污染和改善景观水体水质,既节约了成本,又达到了很好的效果。

  5. Atomic detail visualization of photosynthetic membranes with GPU-accelerated ray tracing

    Energy Technology Data Exchange (ETDEWEB)

    Stone, John E.; Sener, Melih; Vandivort, Kirby L.; Barragan, Angela; Singharoy, Abhishek; Teo, Ivan; Ribeiro, João V.; Isralewitz, Barry; Liu, Bo; Goh, Boon Chong; Phillips, James C.; MacGregor-Chatwin, Craig; Johnson, Matthew P.; Kourkoutis, Lena F.; Hunter, C. Neil; Schulten, Klaus

    2016-07-01

    The cellular process responsible for providing energy for most life on Earth, namely, photosynthetic light-harvesting, requires the cooperation of hundreds of proteins across an organelle, involving length and time scales spanning several orders of magnitude over quantum and classical regimes. Simulation and visualization of this fundamental energy conversion process pose many unique methodological and computational challenges. We present, in two accompanying movies, light-harvesting in the photosynthetic apparatus found in purple bacteria, the so-called chromatophore. The movies are the culmination of three decades of modeling efforts, featuring the collaboration of theoretical, experimental, and computational scientists. We describe the techniques that were used to build, simulate, analyze, and visualize the structures shown in the movies, and we highlight cases where scientific needs spurred the development of new parallel algorithms that efficiently harness GPU accelerators and petascale computers.

  6. 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.

  7. Ação do imazapic+imazapyr sobre a tiririca (Cyperus rotundus e os desnitrificadores em milho Action of imazapic+imazapyr on purple nutsedge (Cyperus rotundus and denitrifying bacteria in corn

    Directory of Open Access Journals (Sweden)

    A.V. Ulbrich

    2004-12-01

    Full Text Available Os objetivos do experimento foram avaliar a eficácia do imazapic+imazapyr sobre a tiririca e a influência desta planta daninha sobre a população de desnitrificadores em solo cultivado com milho. O experimento foi realizado em caixas de 0,70 x 0,30 x 0,30 m, onde foram semeados o milho tolerante às imidazolinonas (C-901CL e plantados 50 bulbos de tiririca. O delineamento experimental foi o inteiramente casualizado, com seis repetições. Os tratamentos foram constituídos por: 1. milho sem tiririca; 2. milho com tiririca; 3. milho com tiririca capinada; 4. milho com tiririca e imazapic+imazapyr (63+21g ha-1 de i.a. em pós-emergência; e 5. milho com tiririca e imazapic+imazapyr (63+21g ha-1 de i.a. em pré-emergência. O herbicida foi eficiente em pós-emergência, diminuindo as manifestações epígeas da tiririca em 41% e proporcionando controle visual de 88% aos 21 dias após a aplicação. Os desnitrificadores do solo aumentaram em seis e dez vezes aos 24 e 54 dias após a semeadura do milho, respectivamente, com a presença de tiririca. A aplicação do herbicida em pós-emergência reduziu a população de desnitrificadores para 1,91x10(5 NMP (número mais provável, 89% menor que a testemunha capinada (16,78x10(5 NMP.The objective of this work was to evaluate the efficacy of imazapic+imazapyr in controling purple nutsedge and its effect on the population of denitrifying bacteria in soil cultivated with corn. The trial was set up in 0.70 x 0.30 x 0.30 m boxes where imidazolinone tolerant corn (C901CL was seeded together with 50 purple nutsedge bulbs. The experimental design was randomized with six replications. The treatments were: 1 corn without nutsedge; 2 corn with nutsedge; 3 corn with cut nutsedge; 4 corn with nutsedge treated with imazapic+imazapyr (63+21 g ha-1 i.a applied in post-emergence and 5 corn with nutsedge treated with imazapic+imazapyr (63+21 g ha-1 i.a, applied in pre-emergence. The herbicide was efficient when

  8. Effect of Applying Phosphate-solubilizing Bacteria to Acid Purple Soil on Yield-increasing of Soybean%酸性紫色土施用溶磷菌对大豆的增产效应

    Institute of Scientific and Technical Information of China (English)

    王芳; 谢庭生

    2012-01-01

    酸性紫色土大豆施用溶磷菌(水剂)的试验结果表明:与常规施肥比较,土壤中有效磷含量提高16.04%;大豆植株分枝数、株高、每株有效结荚数明显增加;最低结荚位明显降低,百粒鲜豆重明显增加;大豆单产提高7.87%,纯收入显著增加,产量增加达极显著水平;对土壤无污染,生态效益好.%Applying phosphate-solubilizing bacteria (water) to acid purple soil where planted soybean to conduct experiment. The results showed that the content of available phosphor in soil increased by 16.04%; the branch number, the plant height, the effective pot-setting number per plant and the fresh weight of bean increased obviously; the lowest pod position reduced obviously, but the fresh weight of 100 beans increased significantly; unit yield of soybean increased by 7.87%, the pure income increased significantly, and the yield-increasing reached significant level; this treatment had no pollution on soil and has good ecological benefit.

  9. 光合细菌处理重金属废水的研究进展%Progress in the application of photosynthetic bacteria to the treatment of heavy metal wastewater

    Institute of Scientific and Technical Information of China (English)

    贾培; 邓旭

    2011-01-01

    Photosynthetic bacteria have been paid more and more attention to the application in wastewater treatment due to its non-toxicity ,quick breeding, easy artificial cultivation and no secondary pollution producing.The physiological and biochemical basis of bioaccumulation heavy metal with photosynthetic bacteria is introduced,and the application of photosynthetic bacteria to the treatment of heavy metal wastewater in recent years is reviewed.Furthermore,the resistance and bioaccumulation capacity of photosynthetic bacteria to different heavy metal ions,and the effects of environmental factors on bioaccumulation performance are discussed. At the end,the prospect of biotreatment of heavy metal wastewater by photosynthetic bacteria is forecast.%光合细菌以其无毒、繁殖快、易人工培养、适应能力强且对环境不产生二次污染等优点而在水污染治理中受到重视.阐明了光合细菌富集重金属的生理生化基础,综述了近年来国内外在利用光合细菌治理重金属污染方面的研究进展,包括光合细菌对重金属的抗性、光合细菌对不同重金属离子的富集性能以及多种环境因素的影响,最后对光合细菌用于重金属废水处理的前景进行了展望.

  10. Förster energy transfer theory as reflected in the structures of photosynthetic light-harvesting systems.

    Science.gov (United States)

    Şener, Melih; Strümpfer, Johan; Hsin, Jen; Chandler, Danielle; Scheuring, Simon; Hunter, C Neil; Schulten, Klaus

    2011-02-25

    Förster’s theory of resonant energy transfer underlies a fundamental process in nature, namely the harvesting of sunlight by photosynthetic life forms. The theoretical framework developed by Förster and others describes how electronic excitation migrates in the photosynthetic apparatus of plants, algae, and bacteria from light absorbing pigments to reaction centers where light energy is utilized for the eventual conversion into chemical energy. The demand for highest possible efficiency of light harvesting appears to have shaped the evolution of photosynthetic species from bacteria to plants which, despite a great variation in architecture, display common structural themes founded on the quantum physics of energy transfer as described first by Förster. Herein, Förster’s theory of excitation transfer is summarized, including recent extensions, and the relevance of the theory to photosynthetic systems as evolved in purple bacteria, cyanobacteria, and plants is demonstrated. Förster’s energy transfer formula, as used widely today in many fields of science, is also derived.

  11. Rhodobaca bogoriensis gen. nov. and sp. nov., an alkaliphilic purple nonsulfur bacterium from African Rift Valley soda lakes.

    Science.gov (United States)

    Milford, A D; Achenbach, L A; Jung, D O; Madigan, M T

    2000-01-01

    From enrichment cultures established for purple nonsulfur bacteria using water and sediment samples from Lake Bogoria and Crater Lake, two soda lakes in the African Rift Valley, three strains of purple nonsulfur bacteria were isolated; strain LBB1 was studied in detail. Cells of strain LBB1 were motile and spherical to rod-shaped, suggesting a relationship to Rhodobacter or Rhodovulum species, and the organism was capable of both phototrophic and chemotrophic growth on a wide variety of organic compounds. Phototrophically grown cultures were yellow to yellow-brown in color and grew optimally at pH 9 (pH range 7.5-10) and 1% NaCl (range 0-10%). In physiological studies of strain LBB1, neither photoautotrophy (H2- or sulfide-dependent) nor nitrogen fixation was observed. Absorption spectra revealed that all three strains contained bacteriochlorophyll a and carotenoids of the spheroidene pathway and synthesized only a light-harvesting (LH) I-type photosynthetic antenna complex. Electron microscopy of cells of strain LBB1 revealed a vesicular intracytoplasmic membrane system, although only a few vesicles were observed per cell. The G+C content of strain LBB1 DNA was 59 mol%, significantly lower than that of known Rhodobacter and Rhodovulum species, and its phylogeny as determined by ribosomal RNA gene sequencing placed it within the Rhodobacter/Rhodovulum clade yet distinct from all described species of either of these genera. The unique assemblage of properties observed in strain LBB1 warrants its inclusion in a new genus of purple nonsulfur bacteria and the name Rhodobaca bogoriensis is proposed herein, the genus name reflecting morphological characteristics and the species epithet referring to the habitat.

  12. The human gut and groundwater harbor non-photosynthetic bacteria belonging to a new candidate phylum sibling to Cyanobacteria.

    Science.gov (United States)

    Di Rienzi, Sara C; Sharon, Itai; Wrighton, Kelly C; Koren, Omry; Hug, Laura A; Thomas, Brian C; Goodrich, Julia K; Bell, Jordana T; Spector, Timothy D; Banfield, Jillian F; Ley, Ruth E

    2013-10-01

    Cyanobacteria were responsible for the oxygenation of the ancient atmosphere; however, the evolution of this phylum is enigmatic, as relatives have not been characterized. Here we use whole genome reconstruction of human fecal and subsurface aquifer metagenomic samples to obtain complete genomes for members of a new candidate phylum sibling to Cyanobacteria, for which we propose the designation 'Melainabacteria'. Metabolic analysis suggests that the ancestors to both lineages were non-photosynthetic, anaerobic, motile, and obligately fermentative. Cyanobacterial light sensing may have been facilitated by regulators present in the ancestor of these lineages. The subsurface organism has the capacity for nitrogen fixation using a nitrogenase distinct from that in Cyanobacteria, suggesting nitrogen fixation evolved separately in the two lineages. We hypothesize that Cyanobacteria split from Melainabacteria prior or due to the acquisition of oxygenic photosynthesis. Melainabacteria remained in anoxic zones and differentiated by niche adaptation, including for symbiosis in the mammalian gut. DOI:http://dx.doi.org/10.7554/eLife.01102.001.

  13. The human gut and groundwater harbor non-photosynthetic bacteria belonging to a new candidate phylum sibling to Cyanobacteria

    Science.gov (United States)

    Di Rienzi, Sara C; Sharon, Itai; Wrighton, Kelly C; Koren, Omry; Hug, Laura A; Thomas, Brian C; Goodrich, Julia K; Bell, Jordana T; Spector, Timothy D; Banfield, Jillian F; Ley, Ruth E

    2013-01-01

    Cyanobacteria were responsible for the oxygenation of the ancient atmosphere; however, the evolution of this phylum is enigmatic, as relatives have not been characterized. Here we use whole genome reconstruction of human fecal and subsurface aquifer metagenomic samples to obtain complete genomes for members of a new candidate phylum sibling to Cyanobacteria, for which we propose the designation ‘Melainabacteria’. Metabolic analysis suggests that the ancestors to both lineages were non-photosynthetic, anaerobic, motile, and obligately fermentative. Cyanobacterial light sensing may have been facilitated by regulators present in the ancestor of these lineages. The subsurface organism has the capacity for nitrogen fixation using a nitrogenase distinct from that in Cyanobacteria, suggesting nitrogen fixation evolved separately in the two lineages. We hypothesize that Cyanobacteria split from Melainabacteria prior or due to the acquisition of oxygenic photosynthesis. Melainabacteria remained in anoxic zones and differentiated by niche adaptation, including for symbiosis in the mammalian gut. DOI: http://dx.doi.org/10.7554/eLife.01102.001 PMID:24137540

  14. Influence of Cd{sup 2+} on the spin state of non-heme iron and on protein local motions in reactions centers from purple photosynthetic bacterium Rhodospirilium rubrum

    Energy Technology Data Exchange (ETDEWEB)

    Lipinska, M [Institute of Nuclear Physics PAN, 31-342 Krakow, Radzikowskiego 152 (Poland); Orzechowska, A [Institute of Physics, Jagiellonian University, 30-059 Krakow, Reymonta 4 (Poland); Fiedor, J; Slezak, T; Zajac, M; Matlak, K; Korecki, J; Halas, A; Burda, K [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, 30-059 Krakow, Reymonta 19 (Poland); Chumakov, A I [European Synchrotron Radiation Facility, BP220, F-38043 Grenoble Cedex (France); Strzalka, K; Fiedor, L, E-mail: burda@novell.ftj.agh.edu.p [Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Gronostajowa 7 (Poland)

    2010-03-01

    Non-heme Fe is a conservative component of the Q-type photosynthetic reaction centers but its function remains unknown. Applying Moessbauer spectroscopy we show that in Rhodospirillum rubrum the non-heme Fe exists mostly in a ferrous low spin state. The binding of Cd{sup 2+} ions in the vicinity of the quinone-Fe complex changes the high spin state of the non-heme Fe into a low spin one characterized by hyperfine parameters similar to those obtained for the non-heme Fe low spin state in untreated reaction centers, as confirmed by Moessbauer measurements. The nuclear inelastic scattering of synchrotron radiation experiments show that the contribution of vibrations at low energies, between 3-15 meV, activated at 240 K are damped in the bacterial reaction centers treated with CdCl{sub 2}. No influence of Cd{sup 2+} ions is observed on the soft vibrational states at 60 K. These results suggest that binding of cadmium cations within the reaction centers may enhance decoupling of the non-heme Fe from the surrounding protein matrix at temperatures higher than 200 K, what can explain the slowing down of electron transfer between the Q{sub A} and Q{sub B} quinones by Cd{sup 2+}.

  15. Characterizations of purple non-sulfur bacteria isolated from paddy fields, and identification of strains with potential for plant growth-promotion, greenhouse gas mitigation and heavy metal bioremediation.

    Science.gov (United States)

    Sakpirom, Jakkapan; Kantachote, Duangporn; Nunkaew, Tomorn; Khan, Eakalak

    2017-04-01

    This study was aimed at selecting purple non-sulfur bacteria (PNSB) isolated from various paddy fields, including Cd- and Zn-contaminated paddy fields, based on their biofertilizer properties. Among 235 PNSB isolates, strain TN110 was most effective in plant growth-promoting substance (PGPS) production, releasing 3.2 mg/L of [Formula: see text] , 4.11 mg/L of 5-aminolevulinic acid (ALA) and 3.62 mg/L of indole-3-acetic acid (IAA), and reducing methane emission up to 80%. This strain had nifH, vnfG and anfG, which are the Mo, V and Fe nitrogenase genes encoded for key enzymes in nitrogen fixation under different conditions. This strain provided 84% and 55% removal of Cd and Zn, respectively. Another isolate, TN414, not only produced PGPS (1.30 mg/L of [Formula: see text] , 0.94 mg/L of ALA and 0.65 mg/L of IAA), but was also efficient in removing both Cd and Zn at 72% and 74%, respectively. Based on 16S rDNA sequencing, strain TN110 was identified as Rhodopseudomonas palustris, while strain TN414 was Rubrivivax gelatinosus. A combination of TN110 and TN414 could potentially provide a biofertilizer, which is a greener alternative to commercial/chemical fertilizers and an agent for bioremediation of heavy metals and greenhouse gas mitigation in paddy fields. Copyright © 2016 Institut Pasteur. All rights reserved.

  16. Effect of metal nanoparticles on energy spectra and optical properties of peripheral light-harvesting LH2 complexes from photosynthetic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Goliney, I.Yu., E-mail: igoliney@kinr.kiev.ua [Institute for Nuclear Research, National Academy of Science of Ukraine, 47 Nauki pr., 03680 Kyiv (Ukraine); Sugakov, V.I. [Institute for Nuclear Research, National Academy of Science of Ukraine, 47 Nauki pr., 03680 Kyiv (Ukraine); Valkunas, L. [Center for Physical Sciences and Technology, Savanoriu Ave. 231, 02300 Vilnius (Lithuania); Department of Theoretical Physics, Vilnius University, Sauletekio 9, Build. 3, 10222 Vilnius (Lithuania); Vertsimakha, G.V. [Institute for Nuclear Research, National Academy of Science of Ukraine, 47 Nauki pr., 03680 Kyiv (Ukraine)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer Excitons of light-harvesting complexes (LH2) hybridize with plasmon modes. Black-Right-Pointing-Pointer Light absorption of LH2 is enhanced by a metal nanoparticle. Black-Right-Pointing-Pointer Using nanoshells allows reaching resonance between molecular and plasmons. Black-Right-Pointing-Pointer Metal nanoparticles introduce additional channel of excitation decay. Black-Right-Pointing-Pointer Light-harvesting may gain from the proper positioning of nanoshells. -- Abstract: The paper explores the theoretical possibility of affecting optical spectra and the quantum yield of the energy transfer in the peripheral light-harvesting complexes (LH2) from photosynthetic bacteria by placing a metal nanoparticle or a nanoshell nearby. An increased probability of the excitonic transition in the LH2 arises due to the borrowing of the oscillator strength from surface plasmons of the metal particle or the nanoshell. While both absorption and quenching of the excitations increase in the vicinity to a metal nanoparticle, having opposite effects, the total yield of the excitation transfer to reaction centers is shown to grow in the certain range of parameters.

  17. Self-aggregation behavior of synthetic zinc 3-hydroxymethyl-13/15-carbonyl-chlorins as models of main light-harvesting components in photosynthetic green bacteria.

    Science.gov (United States)

    Tamiaki, Hitoshi; Yoshimura, Hideaki; Shimamura, Yasuhide; Kunieda, Michio

    2008-01-01

    Zinc complexes of 3-hydroxymethyl-13/15-carbonyl-chlorins having a six-membered lactone as the E-ring were prepared by modifying purpurin-18 as models of bacteriochlorophyll-d, one of the chlorophyllous pigments in the main light-harvesting antenna systems (chlorosomes) of green photosynthetic bacteria. The synthetic 13-carbonylated compound self-aggregated in 1%(v/v) tetrahydrofuran and hexane to give large oligomers possessing red-shifted and broadened electronic absorption bands and intense circular dichroism bands at the shifted Q ( y ) region, indicating that the supramolecular structure of the resulting self-aggregate was similar to those of natural and artificial chlorosomal aggregates. The red-shift value observed here was smaller than the reported values in chlorosomal pigments having a five-membered keto-ring, which was ascribable to a weaker intermolecular hydrogen-bonding of 13-C=O with 3(1)-OH in a supramolecule of the former self-aggregate and suppression of the pi-pi interaction among the composite chlorins. On the other hand, the isomeric 15-carbonylated molecule was monomeric even in the nonpolar organic solvent, confirming the reported proposal that the linear orientation of three interactive moieties, OH, C=O and Zn, in a molecule is requisite for its chlorosomal self-aggregation.

  18. Atomic-level structural and functional model of a bacterial photosynthetic membrane vesicle.

    Science.gov (United States)

    Sener, Melih K; Olsen, John D; Hunter, C Neil; Schulten, Klaus

    2007-10-02

    The photosynthetic unit (PSU) of purple photosynthetic bacteria consists of a network of bacteriochlorophyll-protein complexes that absorb solar energy for eventual conversion to ATP. Because of its remarkable simplicity, the PSU can serve as a prototype for studies of cellular organelles. In the purple bacterium Rhodobacter sphaeroides the PSU forms spherical invaginations of the inner membrane, approximately 70 nm in diameter, composed mostly of light-harvesting complexes, LH1 and LH2, and reaction centers (RCs). Atomic force microscopy studies of the intracytoplasmic membrane have revealed the overall spatial organization of the PSU. In the present study these atomic force microscopy data were used to construct three-dimensional models of an entire membrane vesicle at the atomic level by using the known structure of the LH2 complex and a structural model of the dimeric RC-LH1 complex. Two models depict vesicles consisting of 9 or 18 dimeric RC-LH1 complexes and 144 or 101 LH2 complexes, representing a total of 3,879 or 4,464 bacteriochlorophylls, respectively. The in silico reconstructions permit a detailed description of light absorption and electronic excitation migration, including computation of a 50-ps excitation lifetime and a 95% quantum efficiency for one of the model membranes, and demonstration of excitation sharing within the closely packed RC-LH1 dimer arrays.

  19. Efficiency of light harvesting in a photosynthetic bacterium adapted to different levels of light.

    Science.gov (United States)

    Timpmann, Kõu; Chenchiliyan, Manoop; Jalviste, Erko; Timney, John A; Hunter, C Neil; Freiberg, Arvi

    2014-10-01

    In this study, we use the photosynthetic purple bacterium Rhodobacter sphaeroides to find out how the acclimation of photosynthetic apparatus to growth conditions influences the rates of energy migration toward the reaction center traps and the efficiency of charge separation at the reaction centers. To answer these questions we measured the spectral and picosecond kinetic fluorescence responses as a function of excitation intensity in membranes prepared from cells grown under different illumination conditions. A kinetic model analysis yielded the microscopic rate constants that characterize the energy transfer and trapping inside the photosynthetic unit as well as the dependence of exciton trapping efficiency on the ratio of the peripheral LH2 and core LH1 antenna complexes, and on the wavelength of the excitation light. A high quantum efficiency of trapping over 80% was observed in most cases, which decreased toward shorter excitation wavelengths within the near infrared absorption band. At a fixed excitation wavelength the efficiency declines with the LH2/LH1 ratio. From the perspective of the ecological habitat of the bacteria the higher population of peripheral antenna facilitates growth under dim light even though the energy trapping is slower in low light adapted membranes. The similar values for the trapping efficiencies in all samples imply a robust photosynthetic apparatus that functions effectively at a variety of light intensities. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Appropriate initial temperature improving hydrogen production effect by using photosynthetic-bacteria with straws%适宜初始温度提高秸秆光合细菌制氢效果

    Institute of Scientific and Technical Information of China (English)

    胡建军; 周雪花; 郭婕; 荆艳艳; 张全国

    2014-01-01

    秸秆微粉的光合细菌制氢过程是放热反应,引起的热效应会直接影响产氢效果。为了实现高效低能耗产氢,该文采用秸秆微化粉碎与酶水解预处理相结合的方法,利用自制的秸秆微粉光合细菌制氢反应热测试系统,进行了不同初始温度对秸秆微粉酶解光合细菌制氢反应热的影响试验研究,结果表明:当初始温度为30℃时,最大反应热约为7.1 kJ,最大产热速率约为1.01 kJ/h,反应末期累计反应热约为32.9 kJ,累计产氢量约为745.9 mL,光合细菌制氢反应最充分,产氢效果最好;累计产氢量和底物能量转化率可用累计反应热的二次多项式来表示,光能转化率可用累计反应热的三次多项式来表示。该研究结论可为揭示秸秆微粉酶解光合细菌制氢过程的热量释放变化规律,从生物反应热角度优化工艺参数和预测光合细菌制氢效果提供参考依据。%In photosynthetic-bacteria hydrogen production with enzyme-hydrolyzed fine straws, the growth and reproduction of photosynthetic bacteria will occur in an appropriate temperature range, and the resulting heat effect will have direct influence on hydrogen production due to exothermic processes in the hydrogen production reaction of photosynthetic bacteria with organic acid. Therefore, the research on effects of initial temperature on the reaction heat in the photosynthetic-bacteria hydrogen production with enzyme-hydrolyzed fine straws, is helpful to figure out the heat release rule in such photosynthetic-bacteria hydrogen production, and thus, to provide proper control to the initial temperature to meet the purpose of efficient hydrogen production. In this paper, with the combination method of micro-grinding and enzyme hydrolysis of straws, blank control tests for reaction liquid were performed with photosynthetic hydrogen-production flora of F1, F5, F7, F11, L6, S7 and S9 screened out after flora enrichment

  1. 一种高效光合菌剂对辣椒生长及土壤微生物的影响%Effects of Efficient Photosynthetic Bacteria on Pepper Growth and Soil Microorganism

    Institute of Scientific and Technical Information of China (English)

    田俊岭; 彭桂香; 李永涛; 谭志远; 杨盼盼; 张海春; 刘丽辉; 陈旭东

    2014-01-01

    在一块肥力较低的土壤中,开展辣椒施用光合菌剂的大田实验,研究光合菌剂对辣椒生长发育及土壤微生物活性的影响。结果表明,肥力水平是影响辣椒生长发育的重要因素,施用光合菌剂能明显提高盛果期叶片中氮含量,获得单果重更高、果实更饱满,收获期辣椒植株的长势最好;在整个生育期内,光合菌剂处理的土壤微生物活性最高。因此,在贫瘠的土壤中,在补充肥力的基础上,光合菌剂能一定程度上改善土壤微生态环境,促进辣椒植株生长和果实发育,具有良好的应用前景。%A pepper field experiment was conducted for applying photosynthetic bacteria in relatively poor-fertility soil to study the effects on pepper growth and soil microbial activity. The results showed that fertility level was an important factor affecting the pepper growth, the photosynthetic bacteria could significantly improve nitrogen content in leaves to get heavier and fuller fruits, and plants with best growth at harveat timeof. During the whole growth period, soil treated by photosynthetic bacteria kept the highest soil microbial activity. Thus, on the basis of the fertility supplement, photosynthetic bacteria can improve soil microenvironment of poor soil,promote pepper plant growth and fruit development,showing considerable application prospects.

  2. Effect of lmmobilized Photosynthetic Bacteria on Water Environment in Aquaculture%固定化浓缩光合细菌对养殖水环境的影响

    Institute of Scientific and Technical Information of China (English)

    易力; 汪洋; 陈万光; 张耀武

    2011-01-01

    为探索养殖水环境的生物修复作用,进行了固定化光合细菌对养殖水环境的生物修复试验.结果表明,接种固定化光合细菌后12 d,养殖水体的COD值、氨氮分别降低54.29%、80%,DO值上升44%,pH值上升到8.8.表明,应用固定化光合细菌有利于降低水产养殖水体的污染,从而促进养殖业的健康发展.%The effect of immobilized photosynthetic bacteria on water environment in aquaculture was studied to probe the bioremediation of water environment in aquaculture.The results showed that COD and ammonia nitrogen value of aquaculture water inoculated with immobilized photosynthetic bacteria reduced by 54.29% and 80% respectively, and it's DO and pH value went up by 44% and to 8.8, which indicated that immobilized photosynthetic bacteria can improve water quality in aquaculture effectively for healthy development of aquaculture.

  3. Extraction and Stability of Carotenoids of Photosynthetic Bacteria%光合细菌类胡萝卜素的提取及稳定性研究

    Institute of Scientific and Technical Information of China (English)

    李彦芹; 李春青; 李振华; 康现江

    2011-01-01

    To distill, separate, purify carotenoids from photosynthetic bacteria 3 and study its stability, some kinds of organic solvent are selected to extract carotenoids from photosynthetic bacteria 3 and then they are separated and purified them via saponification method, and are selected the stability of carotenoids is studied under different conditions of light, temperature, pH and metallic ions. The result suggests that the best extraction solvent is the component solvent of ethyl acetate and methanol. When their volume is 7:2, the quantity of PSB 3 and the extraction resolver are 0. 1 g to 5 mL and the extraction time is 8h, the extraction rate is the highest. In condition of sun light shining 72 h the lost rate of carotenoids reach 88. 3%. The carotenoids are tolerant to temperature to some extent, but easy to lose activity under high temperature, relatively stable in the neutral condition, but unstable in the strong acidic or alkaline condition, and lost 92% in the condition pH2 after 32 h. The carotenoids are sensitive to metallic ion especially to Fe3+ , losing 77. 3% after 24 h and higher endurable to K+ only losing 5. 6% after 24 h. Therefore the carotenoids should be handled or conserved in neutral condition of low temperature, avoiding light and keeping off metalware.%对光合细菌3号菌株进行类胡萝卜素的提取、分离纯化及稳定性研究.选取几种有机溶剂提取光合细菌类胡萝卜素并用皂化法分离纯化,通过可见分光光度计研究类胡萝卜素在不同光照、温度,pH和金属离子条件下的稳定性.结果表明:最佳提取溶剂为体积比7:2的乙酸乙酯和甲醇的混合溶剂,当菌体量与提取溶剂为0.1 g/5 mL,提取时间为8h时浸提率最高.该菌类胡萝卜素在自然光照直射72 h损失88.3%;对温度有一定的耐受性,但高温容易导致其失活;pH中性条件下相对稳定,强酸强碱条件下不稳定,pH 2条件下32 h损失了92%;对金属离子敏感,尤其对Fe3

  4. Effects of conservation tillage on soil photosynthetic bacteria and typeⅡ methanotrophs%保护性耕作对土壤光合细菌和Ⅱ型甲烷氧化菌的影响

    Institute of Scientific and Technical Information of China (English)

    王敬敬; 李新宇; 徐明恺; 苏振成; 李旭; 孙健; 张惠文

    2012-01-01

    保护性耕作对土壤微生物具有明显的保护效应,但是其对土壤光合细菌和甲烷氧化菌的影响却鲜有报道.本文采用土壤宏基因组16S rDNA变性梯度凝胶电泳(DGGE)和荧光定量PCR技术比较了不同耕作模式(免耕和传统翻耕)和不同秸秆覆盖量(0、50%、100%)对潮土中光合细菌和Ⅱ型甲烷氧化菌数量和群落结构的影响.结果表明:免耕土壤中光合细菌的多样性(多样性指数H=2.47)显著高于传统翻耕土壤(多样性指数H=2.35),且与土壤总氮呈显著正相关,数量略低于传统翻耕土壤;光合细菌的数量和多样性虽均随着秸秆覆盖量的增加而有所增加,但不显著;虽然免耕和秸秆覆盖对Ⅱ型甲烷氧化菌数量和多样性产生了有益的影响,但是耕作模式、秸秆覆盖及二者互作对其影响均不显著;不同处理中光合细菌和Ⅱ型甲烷氧化菌的种群结构无明显变化,光合细菌优势种群以根瘤菌目(Rhizobiales)和鞘脂单胞菌目(Sphingomonadales)为主,Ⅱ型甲烷氧化菌优势种群主要为甲基孢囊菌科(Methylocystaceae)的细菌类群.%Conservation tillage has beneficial effects on soil microbes, but the effects on soil photosynthetic,bacteria and methanotrophs are rarely reported. In this study, denaturing gel gradient electrophoresis (DGGE) and quantitative PCR technique were adopted to investigate the abundance and community structure of photosynthetic bacteria and type Ⅱ methanotrophs in a fluvo-aquic soil as affected by different tillage modes ( no-tillage and conventional tillage) and straw mulching (0, 50% , 100% ). Under no tillage, the diversity of soil photosynthetic bacteria was significantly higher but the abundance was slightly lower, as compared with those under conventional tillage, and there was a significant positive correlation between the diversity of soil photosynthetic bacteria and the soil total nitrogen. Both the abundance and the diversity of soil

  5. 染料高效脱色光合细菌的分离与分析%Separation and analysis of photosynthetic bacteria of high efficiency decolorization

    Institute of Scientific and Technical Information of China (English)

    李彦芹; 昌艳萍; 李春青; 陈涵茜; 康现江

    2012-01-01

    In order to enhance the biological treatment of dyestuff wastewater, a strain HL of photo-synthetic bacteria with high efficiency on the dye decoloring ability were separated and analyzed. The effects of the strain HL on decolourization of five dyes under different conditions such as the choice of pH, carbon source and nitrogen source were studied. Results showed that the strain HL colony was bright red, circular, moist, smooth, slightly protuberant, edge tidy, diameter 0.5 - 2.0 mm, individual assume spiral-shaped, single extremely born flagellum, gram's staining for negative, contain bacteria chlorophyll-a for photosynthesis. And the decoloring ability were determined on the five types of dye , including on the active liquor and direct Hulan of decolorization optimal, especially for the treatment of ability within 24 h on direct Hulan was 100%. Strain HL in a neutral environment, respectively with glucose and ammonium chloride as decoloring medium carbon source and nitrogen source, the decolored rate and degradation rate of direct Hulan were 100% and 98. 67% respectively.%为增强染料废水的生物处理,从印染厂的污泥中分离筛选出1株高效脱色光合细菌HL.对其在不同pH、碳源和氮源的条件下对5种染料的脱色效果进行了研究.结果表明,菌株HL菌落呈鲜红色,圆形、光滑、湿润、稍突起、边缘整齐,直径0.5~2.0 mm;个体呈螺旋状,单根极生鞭毛,革兰氏染色为阴性,含有细菌叶绿素a,可进行光合作用.对活性艳红和直接胡兰的脱色效果显著,特别是对直接胡兰在24 h内脱色率达到100%.菌株HL在中性环境下,分别以葡萄糖和氯化铵作为脱色培养基的碳源和氮源时,对直接胡兰的脱色率和降解率分别达到100%和98.67%.

  6. Light harvesting, electron transfer and electron cycling of a native photosynthetic membrane adsorbed onto a gold surface

    NARCIS (Netherlands)

    Magis, G.J; Hollander, den M. -J.; Onderwaater, W. G.; Olsen, J.D.; Hunter, C.N.; Aartsma, T.J.; Frese, R.N.

    2010-01-01

    Photosynthetic membranes comprise a network of light harvesting and reaction center pigment–protein complexes responsible for the primary photoconversion reactions: light absorption, energy transfer and electron cycling. The structural organization of membranes of the purple bacterial species Rb. sp

  7. A KDP-LIKE, HIGH-AFFINITY, K+-TRANSLOCATING ATPASE IS EXPRESSED DURING GROWTH OF RHODOBACTER-SPHAEROIDES IN LOW POTASSIUM MEDIA - DISTRIBUTION OF THIS K+-ATPASE AMONG PURPLE NONSULFUR PHOTOTROPHIC BACTERIA

    NARCIS (Netherlands)

    ABEE, T; HELLINGWERF, KJ; BAKKER, EP; SIEBERS, A; KONINGS, WN

    1992-01-01

    Cells of the purple non-sulphur bacterium Rhodobacter sphaeroides express a high-affinity K+ uptake system when grown in media with low K+ concentrations. Antibodies against the catalytic KdpB protein or the whole KdpABC complex of Escherichia coli cross-react with a 70.0 kDa R. sphaeroides protein

  8. Distinguishing the roles of energy funnelling and delocalization in photosynthetic light harvesting.

    Science.gov (United States)

    Baghbanzadeh, Sima; Kassal, Ivan

    2016-03-14

    Photosynthetic complexes improve the transfer of excitation energy from peripheral antennas to reaction centers in several ways. In particular, a downward energy funnel can direct excitons in the right direction, while coherent excitonic delocalization can enhance transfer rates through the cooperative phenomenon of supertransfer. However, isolating the role of purely coherent effects is difficult because any change to the delocalization also changes the energy landscape. Here, we show that the relative importance of the two processes can be determined by comparing the natural light-harvesting apparatus with counterfactual models in which the delocalization and the energy landscape are altered. Applied to the example of purple bacteria, our approach shows that although supertransfer does enhance the rates somewhat, the energetic funnelling plays the decisive role. Because delocalization has a minor role (and is sometimes detrimental), it is most likely not adaptive, being a side-effect of the dense chlorophyll packing that evolved to increase light absorption per reaction center.

  9. Charm of Purple Clay A private museum in Wuxi is devoted to purple-clay art

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Purple-clay art pieces will be on display in a museum opening soon in Wuxi, Jiangsu Province. The museum, named Shuaiyuan Purple Clay Museum, is part of the Shuaiyuan Purple Clay Art Exhibition Center

  10. The bioremediation of aquaculture water with photosynthetic bacteria and bacillus%光合细菌与芽孢杆菌对淡水养殖水体修复实验研究

    Institute of Scientific and Technical Information of China (English)

    周丹丹; 李延云; 聂宇燕; 刘春和; 高逢敬; 赵毅; 杨威; 唐鹤鸣; 吴明立

    2011-01-01

    Photosynthetic bacteria and bacillus were used on the bioremediation of aquaculture water to reduce its pollution.The ammonia nitrogen content in water,pH value,COD and DO were determined.Compared with the blank,the application of photosynthetic bacteria%为降低淡水养殖水体的污染程度,实验选用光合细菌与芽孢杆菌对养殖水体进行生物修复,测定水体氨、氮含量、pH值、化学耗氧量以及溶氧量的变化。结果表明,与空白对照组相比,使用光合细菌与芽孢杆菌后,水体中的氨、氮含量降低73.1%,pH值下降4.2%,化学耗氧量降低46.3%,溶氧量升高9.7%,净化水质效果明显。

  11. Measuring and modeling twilight's purple light

    Science.gov (United States)

    Lee, Raymond L.; Hernández-Andrés, Javier

    2003-01-01

    During many clear twilights, much of the solar sky is dominated by pastel purples. This purple light's red component has long been ascribed to transmission through and scattering by stratospheric dust and other aerosols. Clearly the vivid purples of post-volcanic twilights are related to increased stratospheric aerosol loading. Yet our time-series measurements of purple-light spectra, combined with radiative transfer modeling and satellite soundings, indicate that background stratospheric aerosols by themselves do not redden sunlight enough to cause the purple light's reds. Furthermore, scattering and extinction in both the troposphere and the stratosphere are needed to explain most purple lights.

  12. Construction and Characterization of B850-Only LH2 Energy Transfer System in Purple Bacteria%紫细菌B800缺失LH2能量传递模型的构建及性质

    Institute of Scientific and Technical Information of China (English)

    李凯; 赵春贵; 岳慧英; 杨素萍; 曲音波; 焦念志

    2015-01-01

    To seek microscopic molecular mechanism of energy transfer and complex reconstitution in the photosynthesis ,the conditions for construction of B850‐only peripheral light‐harvesting complex (LH2) and their properties were investigated using absorption ,fluorescence spectroscopy ,molecular sieve chromatography ,ultrafiltration and sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS‐PAGE) from the purple bacteria .The results indicated that bacteriochlorophylls (BChl) of B800 incu‐bated in 10 mmo · L -1 Tris‐HCl (pH 8.0) buffer are selectively released from their binding sites of LH2 of Rhodobacter azoto‐formans(A‐LH2)by0.08% (W/V)SDS.B850‐onlyA‐LH2wasconstructedafterremovingfreeBChlmixingwith10% meth‐yl alcohol by ultrafiltration .B850 BChl was released after A‐LH2 was incubated for 240 min in dark at room temperature (RT) . While BChl of B800 incubated in pH 1.9 buffer were selectively released from their binding sites of LH 2 of Rhodopseudomonas palustris (P‐LH2) .The authors acquired two components using molecular sieve chromatography .Free BChl of one component was not removed and self‐assembled to P‐LH2 .The other removed free BChl and B850‐only P‐LH2 was constructed .B850 un‐changed after P‐LH2 was incubated .P‐LH2 αandβsubunits have different molecular weights ,but those of A‐LH2 are in the contrary .It is concluded that B850‐only P‐LH2 is more stable than A‐LH2 .The enigmatic split of the B800 absorption band was not observed in these LH2 ,but we acquired two kinds of B800‐released LH2 from Rhodopseudomonas palustris .The authors’ results may provide a new light to separate homogeneous Apoprotein LH 2 .%构建B800缺失L H2对于阐明光合作用中光能传递的分子机制与捕光复合体组装机制具有重要意义。采用吸收光谱、荧光光谱、分子筛层析、超滤和SDS‐PAGE等方法研究了紫细菌两个典型种外周捕光复合体(LH2)约800 nm特征光谱(B800

  13. Molecular factors controlling photosynthetic light harvesting by carotenoids.

    Science.gov (United States)

    Polívka, Tomás; Frank, Harry A

    2010-08-17

    Carotenoids are naturally occurring pigments that absorb light in the spectral region in which the sun irradiates maximally. These molecules transfer this energy to chlorophylls, initiating the primary photochemical events of photosynthesis. Carotenoids also regulate the flow of energy within the photosynthetic apparatus and protect it from photoinduced damage caused by excess light absorption. To carry out these functions in nature, carotenoids are bound in discrete pigment-protein complexes in the proximity of chlorophylls. A few three-dimensional structures of these carotenoid complexes have been determined by X-ray crystallography. Thus, the stage is set for attempting to correlate the structural information with the spectroscopic properties of carotenoids to understand the molecular mechanism(s) of their function in photosynthetic systems. In this Account, we summarize current spectroscopic data describing the excited state energies and ultrafast dynamics of purified carotenoids in solution and bound in light-harvesting complexes from purple bacteria, marine algae, and green plants. Many of these complexes can be modified using mutagenesis or pigment exchange which facilitates the elucidation of correlations between structure and function. We describe the structural and electronic factors controlling the function of carotenoids as energy donors. We also discuss unresolved issues related to the nature of spectroscopically dark excited states, which could play a role in light harvesting. To illustrate the interplay between structural determinations and spectroscopic investigations that exemplifies work in the field, we describe the spectroscopic properties of four light-harvesting complexes whose structures have been determined to atomic resolution. The first, the LH2 complex from the purple bacterium Rhodopseudomonas acidophila, contains the carotenoid rhodopin glucoside. The second is the LHCII trimeric complex from higher plants which uses the carotenoids

  14. 1H NMR of High-Potential Iron-Sulfur Protein from the Purple Non-Sulfur Bacterium Rhodoferax fermentans

    DEFF Research Database (Denmark)

    Ciurli, Stefano; Cremonini, Mauro Andrea; Kofod, Pauli

    1996-01-01

    Oxidized and reduced forms of high-potential iron-sulfur protein (HiPIP) from the purple non-sulfur photosynthetic bacterium Rhodoferux fermentans have been characterized using 1H-NMR spectroscopy. Pairwise and sequence-specific assignments of hyperfine-shifted 1H-NMR signals to protons of cysteine...

  15. Structure-function investigations of bacterial photosynthetic reaction centers.

    Science.gov (United States)

    Leonova, M M; Fufina, T Yu; Vasilieva, L G; Shuvalov, V A

    2011-12-01

    During photosynthesis light energy is converted into energy of chemical bonds through a series of electron and proton transfer reactions. Over the first ultrafast steps of photosynthesis that take place in the reaction center (RC) the quantum efficiency of the light energy transduction is nearly 100%. Compared to the plant and cyanobacterial photosystems, bacterial RCs are well studied and have relatively simple structure. Therefore they represent a useful model system both for manipulating of the electron transfer parameters to study detailed mechanisms of its separate steps as well as to investigate the common principles of the photosynthetic RC structure, function, and evolution. This review is focused on the research papers devoted to chemical and genetic modifications of the RCs of purple bacteria in order to study principles and mechanisms of their functioning. Investigations of the last two decades show that the maximal rates of the electron transfer reactions in the RC depend on a number of parameters. Chemical structure of the cofactors, distances between them, their relative orientation, and interactions to each other are of great importance for this process. By means of genetic and spectral methods, it was demonstrated that RC protein is also an essential factor affecting the efficiency of the photochemical charge separation. Finally, some of conservative water molecules found in RC not only contribute to stability of the protein structure, but are directly involved in the functioning of the complex.

  16. Development of technology for organic wastewater treatment by microorganisms and production of materials for conserving environment. Part 1. ; Organic wastewater treatment by photoshynthetic bacteria and microalgae. Biseibutsu ni yoru yukikei haisui shori to yojo biseibutsu no shigenka ni kansuru kenkyu. 1. ; Kogosei saikin to sorui ni yoru haisui shori ni kansuru kihonteki kento

    Energy Technology Data Exchange (ETDEWEB)

    Kato, A.; Kita, D.; Kubotera, T.; Tsuji, H. (Obayashi Corp., Tokyo (Japan))

    1994-02-10

    The present report introduces a system which simultaneously executes the purification of organic wastewater and recovery of recyclable matters. The system uses photosynthetic bacteria and microalgae as well as the conventionally used activated sludge bacteria. Environmental maintenance use agents are produced by processing bacteria and algae generated during the wastewater treatment. The photosynthetic bacteria are purple non-sulfuric bacteria, which also contain amino acid, vitamin and other useful physiologically activated matter. The wastewater treatment which utilizes them has the advantage of miniaturizing the plant and lowering the power. As algae, chlorella and spirulina are used in order to remove the nitrogen and phosphorus in the water to be treated. The following is an actual result of wastewater treatment in a beancurd maker's plant: if purple non-sulfuric bacteria are used, high concentration organic wastewater can be treated without dilution so that the plant can be miniaturized. The chlorella culture is so effective that the nitrogen and phosphorus remaining in the wastewater are absorbed and removed by the chlorella with its increasing. 9 refs., 13 figs., 2 tabs.

  17. High efficiency light harvesting by carotenoids in the LH2 complex from photosynthetic bacteria: unique adaptation to growth under low-light conditions.

    Science.gov (United States)

    Magdaong, Nikki M; LaFountain, Amy M; Greco, Jordan A; Gardiner, Alastair T; Carey, Anne-Marie; Cogdell, Richard J; Gibson, George N; Birge, Robert R; Frank, Harry A

    2014-09-25

    Rhodopin, rhodopinal, and their glucoside derivatives are carotenoids that accumulate in different amounts in the photosynthetic bacterium, Rhodoblastus (Rbl.) acidophilus strain 7050, depending on the intensity of the light under which the organism is grown. The different growth conditions also have a profound effect on the spectra of the bacteriochlorophyll (BChl) pigments that assemble in the major LH2 light-harvesting pigment-protein complex. Under high-light conditions the well-characterized B800-850 LH2 complex is formed and accumulates rhodopin and rhodopin glucoside as the primary carotenoids. Under low-light conditions, a variant LH2, denoted B800-820, is formed, and rhodopinal and rhodopinal glucoside are the most abundant carotenoids. The present investigation compares and contrasts the spectral properties and dynamics of the excited states of rhodopin and rhodopinal in solution. In addition, the systematic differences in pigment composition and structure of the chromophores in the LH2 complexes provide an opportunity to explore the effect of these factors on the rate and efficiency of carotenoid-to-BChl energy transfer. It is found that the enzymatic conversion of rhodopin to rhodopinal by Rbl. acidophilus 7050 grown under low-light conditions results in nearly 100% carotenoid-to-BChl energy transfer efficiency in the LH2 complex. This comparative analysis provides insight into how photosynthetic systems are able to adapt and survive under challenging environmental conditions.

  18. Light Absorption and Energy Transfer in the Antenna Complexes of Photosynthetic Organisms.

    Science.gov (United States)

    Mirkovic, Tihana; Ostroumov, Evgeny E; Anna, Jessica M; van Grondelle, Rienk; Govindjee; Scholes, Gregory D

    2017-01-25

    The process of photosynthesis is initiated by the capture of sunlight by a network of light-absorbing molecules (chromophores), which are also responsible for the subsequent funneling of the excitation energy to the reaction centers. Through evolution, genetic drift, and speciation, photosynthetic organisms have discovered many solutions for light harvesting. In this review, we describe the underlying photophysical principles by which this energy is absorbed, as well as the mechanisms of electronic excitation energy transfer (EET). First, optical properties of the individual pigment chromophores present in light-harvesting antenna complexes are introduced, and then we examine the collective behavior of pigment-pigment and pigment-protein interactions. The description of energy transfer, in particular multichromophoric antenna structures, is shown to vary depending on the spatial and energetic landscape, which dictates the relative coupling strength between constituent pigment molecules. In the latter half of the article, we focus on the light-harvesting complexes of purple bacteria as a model to illustrate the present understanding of the synergetic effects leading to EET optimization of light-harvesting antenna systems while exploring the structure and function of the integral chromophores. We end this review with a brief overview of the energy-transfer dynamics and pathways in the light-harvesting antennas of various photosynthetic organisms.

  19. [Photosynthetic activity and components of the electron transport chain in the aerobic bacteriochlorophyll A-containing bacterium Roseinatronobacter thiooxidans].

    Science.gov (United States)

    Stadnichuk, I N; Ianiushin, M F; Boĭchenko, V A; Lukashev, E P; Boldareva, E N; Solov'ev, A A; Gorlenko, V M

    2009-01-01

    Bioenergetics of the aerobic bacteriochlorophyll a-containing (BCl a) bacterium (ABC bacterium) Roseinatronobacter thiooxidans is a combination of photosynthesis, oxygen respiration, and oxidation of sulfur compounds under alkaliphilic conditions. The photosynthetic activity of Rna. thiooxidans cells was established by the photoinhibition of cell respiration and reversible photobleaching discoloration of the BCl a of reaction centers (RC), connected by the chain of electron transfer with cytochrome c551 oxidation. The species under study, like many purple bacteria and some of the known ABC bacteria, possesses a light-harvesting pigment-protein (LHI) complex with the average number of 30 molecules of antenna BCl a per one photosynthetic RC. Under microaerobic growth conditions, the cells contained bc1 complex and two terminal oxidases: cbb3-cytochrome oxidase and the alternative cytochrome oxidase of the a3 type. Besides, Rna. thiooxidans was shown to have several different soluble low- and high-potential cytochromes c, probably associated with the ability of utilizing sulfur compounds as additional electron donors.

  20. Purple Pelisse: A specialty fingerling potato with purple skin and flesh and medium specific gravity

    Science.gov (United States)

    Purple Pelisse is a specialty fingerling potato with purple skin and dark purple flesh. It has medium maturity and sets a large number of smooth, small, fingerling-shaped tubers. The tubers have medium specific gravity and high levels of antioxidants. This potato variety is mainly intended for the f...

  1. Temperature dependent LH1→RC energy transfer in purple bacteria Tch. tepidum with shiftable LH1-Qy band: A natural system to investigate thermally activated energy transfer in photosynthesis.

    Science.gov (United States)

    Ma, Fei; Yu, Long-Jiang; Wang-Otomo, Zheng-Yu; van Grondelle, Rienk

    2016-04-01

    The native LH1-RC complex of the purple bacterium Thermochromatium (Tch.) tepidum has an ultra-red LH1-Qy absorption at 915nm, which can shift to 893 and 882nm by means of chemical modifications. These unique complexes are a good natural system to investigate the thermally activated energy transfer process, with the donor energies different while the other factors (such as the acceptor energy, special pair at 890nm, and the distance/relative orientation between the donor and acceptor) remain the same. The native B915-RC, B893-RC and B882-RC complexes, as well as the LH1-RC complex of Rhodobacter (Rba.) sphaeroides were studied by temperature-dependent time-resolved absorption spectroscopy. The energy transfer time constants, kET(-1), are 65, 45, 46 and 45ps at room temperature while 225, 58, 85, 33ps at 77K for the B915-RC, B893-RC, B882-RC and Rba. sphaeroides LH1-RC, respectively. The dependences of kET on temperature have different trends. The reorganization energies are determined to be 70, 290, 200 and 45cm(-1), respectively, by fitting kET vs temperature using Marcus equation. The activation energies are 200, 60, 115 and 20cm(-1), respectively. The influences of the structure (the arrangement of the 32 BChl a molecules) on kET are discussed based on these results, to reveal how the B915-RC complex accomplishes its energy transfer function with a large uphill energy of 290cm(-1).

  2. Process optimization of brewers' grains fermentation using photosynthetic bacteria to make fish feed%光合菌发酵啤酒糟制鱼饲料工艺优化

    Institute of Scientific and Technical Information of China (English)

    张健; 冯学愚; 刘小彬; 谢刚; 方勤; 罗辉

    2011-01-01

    In order to get high-quality fish feed from brewers' spent grains, an anaerobic fermentation installation was set up, and the brewers' grains as raw material were pretreated by anaerobic photosynthetic bacteria separated from drainage ditch of brewers' grains in a beer factory. The orthogonal experiments were conducted based on single factors to study the semisolid fermentation technique for anaerobic photosynthetic bacteria culture. The results showed that the satisfied fermentation effect was attained under the technical conditions of dry brewers' grains/water 1:9 (mass fraction), inoculation amount 9%, illumination intensity 1100 Lx, fermentation time 5 d, fermentation temperature 30 ℃, and material thickness 3 cm. After fermentation, the real protein concentration of brewers' grains increased from 17.0% to 41.6%, the cellulose concentration decreased from 15.3% to 7.0%, the crude fat concentration increased from 5.9% to 6.6%, the crude ash concentration increased from 3.8% to 4.1%, the total phosphorus concentration increased from 0.6% to 1.3%, and the water concentration of dried brewers' grains was 9.8%. All the six indices satisfied the China standard of Grass Carp's fingerling (SC/T 1024-2002). The results can provide references for making active photosynthetic bacteria fish feed from brewers' grains.%为把啤酒糟加工成优质鱼饲料,从啤酒厂啤酒糟排水沟中以厌氧法分离出一株光合菌为菌种,对原料啤酒糟进行预处理,自组装厌氧发酵装置,采用单因素与正交试验法,对啤酒糟半固态培养光合菌的条件进行了研究.结果表明,当料水比1∶9(干糟:水,g/g)、接种量9%、光照强度1 100Lx、发酵时间5d、发酵温度30℃、料层厚度3 cm时,发酵效果较好.发酵后啤酒干糟真蛋白质量分数可从17.0%上升至41.6%、粗纤维素从15.3%下降至7.0%、粗脂肪从5.9%上升至6.6%、粗灰分从3.8%上升至4.1%、总磷从0.6%上升至1.3

  3. Solid-state NMR applied to photosynthetic light-harvesting complexes

    NARCIS (Netherlands)

    Pandit, A.; Groot, de H.J.M.

    2012-01-01

    This short review describes how solid-state NMR has provided a mechanistic and electronic picture of pigment–protein and pigment–pigment interactions in photosynthetic antenna complexes. NMR results on purple bacterial antenna complexes show how the packing of the protein and the pigments inside the

  4. Solid-state NMR applied to photosynthetic light-harvesting complexes

    NARCIS (Netherlands)

    Pandit, A.; Groot, de H.J.M.

    2012-01-01

    This short review describes how solid-state NMR has provided a mechanistic and electronic picture of pigment–protein and pigment–pigment interactions in photosynthetic antenna complexes. NMR results on purple bacterial antenna complexes show how the packing of the protein and the pigments inside the

  5. Acclimation of the photosynthetic response of Chromatium vinosum to light-limiting conditions

    NARCIS (Netherlands)

    Sanchez, O; Van Gemerden, H; Mas, J

    1998-01-01

    The photosynthetic response of the purple sulfur bacterium Chromatium vinosum DSM 185 to different degrees of illumination was analyzed. The microorganism was grown in continuous culture, and samples were taken from the effluent of the culture and incubated at different irradiances to determine the

  6. A serendipic legacy: Erwin Esmarch's isolation of the first photosynthetic bacterium in pure culture.

    Science.gov (United States)

    Gest, H

    1995-01-01

    During the 1880's, Erwin von Esmarch was a junior associate ('Assistent') of Robert Koch studying bacteria of medical significance. In 1887, he isolated the first example of spiral-shaped bacteria in pure culture, from the dry residue of a dead mouse that he had suspended sometime earlier in Berlin tap-water. Under certain conditions, colonies of the organism were the color of red wine, and this led Esmarch to name the bacterium Spirillum rubrum. Twenty years later, Hans Molisch demonstrated that S. rubrum, an apparent heterotroph, was in fact a non-oxygenic purple photosynthetic bacterium, and it was renamed Rhodospirillum rubrum. Esmarch was a careful investigator and his classic paper of 1887 details the serendipitous isolation and general characteristics of the first pure culture of an anoxyphototroph, which later played a prominent role as an experimental system for study of basic aspects of bacterial photosynthesis. This report includes an English translation of his original paper (in German), a commentary on the historical significance of 'Esmarch's spirillum', and a summary of Esmarch's career.

  7. Panda Apparel Adds Neon Purple Color

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Neon Tees division of the Panda Apparel Group is introducing Neon Purple to their line. Bright with a capital B has been on top of the fashion trends for the past year. With the addition of neon purple, an exciting new offering is available to apparel

  8. Optimal level of ethanol for extraction of Mistletoe preparations transformed by photosynthetic bacteria%光合细菌转化槲寄生制剂乙醇提取浓度的研究

    Institute of Scientific and Technical Information of China (English)

    漆小梅; 郑庆红; 杨官娥; 张肇铭

    2011-01-01

    目的 确定光合细菌(PSB)转化槲寄生制剂中槲寄生乙醇提取的最佳浓度.方法 以荷Lewis肺癌小鼠为模型,以抑瘤率、免疫指标、抗氧化指标为标准进行筛选.结果 PSB转化槲寄生制剂的各项指标均优于单纯的槲寄生制剂,其中以PSB转化槲寄生制剂Ⅱ的各项指标为最佳.结论 槲寄生75%乙醇提取物所制光合细菌转化槲寄生制剂为最佳.%Objective To determine the optimal level of ethanol for extraction of mistletoe preparations transformed by photosynthetic bacteria (PSB). Methods The screening of ethanol level was performed using mice model of Lewis-lung tumor and based on the tumor inhibition rate, immune parameters and antioxidation parameters. Results All parameters for PSB transformed mistletoe preparations were better than those for untransformed mistletoe preparations. Mistletoe preparations Ⅱ transformed by PSB showed the most favorable values of parameters. Conclusion PSB transformed mistletoe preparations extracted with 75% ethanol appears to be with best anti-tumor activity.

  9. Spin densities from subsystem density-functional theory: Assessment and application to a photosynthetic reaction center complex model

    Energy Technology Data Exchange (ETDEWEB)

    Solovyeva, Alisa [Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Technical University Braunschweig, Institute for Physical and Theoretical Chemistry, Hans-Sommer-Str. 10, 38106 Braunschweig (Germany); Pavanello, Michele [Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Neugebauer, Johannes [Technical University Braunschweig, Institute for Physical and Theoretical Chemistry, Hans-Sommer-Str. 10, 38106 Braunschweig (Germany)

    2012-05-21

    Subsystem density-functional theory (DFT) is a powerful and efficient alternative to Kohn-Sham DFT for large systems composed of several weakly interacting subunits. Here, we provide a systematic investigation of the spin-density distributions obtained in subsystem DFT calculations for radicals in explicit environments. This includes a small radical in a solvent shell, a {pi}-stacked guanine-thymine radical cation, and a benchmark application to a model for the special pair radical cation, which is a dimer of bacteriochlorophyll pigments, from the photosynthetic reaction center of purple bacteria. We investigate the differences in the spin densities resulting from subsystem DFT and Kohn-Sham DFT calculations. In these comparisons, we focus on the problem of overdelocalization of spin densities due to the self-interaction error in DFT. It is demonstrated that subsystem DFT can reduce this problem, while it still allows to describe spin-polarization effects crossing the boundaries of the subsystems. In practical calculations of spin densities for radicals in a given environment, it may thus be a pragmatic alternative to Kohn-Sham DFT calculations. In our calculation on the special pair radical cation, we show that the coordinating histidine residues reduce the spin-density asymmetry between the two halves of this system, while inclusion of a larger binding pocket model increases this asymmetry. The unidirectional energy transfer in photosynthetic reaction centers is related to the asymmetry introduced by the protein environment.

  10. Evidence for high-pressure-induced rupture of hydrogen bonds in LH2 photosynthetic antenna pigment-protein complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kangur, L; Leiger, K; Freiberg, A [Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia)

    2008-07-15

    The bacteriochlorophyll a-containing LH2 light harvesting complex is an integral membrane protein that catalyzes the photosynthetic process in purple photosynthetic bacteria. The LH2 complexes from Rhodobacter sphaeroides show characteristic strong absorbance at 800 and 850 nm due to the bacteriochlorophyll a molecules confined in two separate areas of the protein. Using these cofactors as intrinsic probes to monitor changes in membrane protein structure, we investigate the response to high hydrostatic pressure up to 2.1 GPa of LH2 complexes embedded into natural membrane environment or extracted with detergent. We demonstrate that high pressure does induce significant alterations to the tertiary structure of the protein in proximity of the protein-bound bacteriochlorophyll a molecules, including breakage of the hydrogen bond they are involved in. The membrane-embedded complexes appear more resilient to damaging effects of the compression than the complexes extracted into detergent environment. This difference has tentatively been explained by more compact structure of the membrane-embedded complexes.

  11. Equilibration kinetics in isolated and membrane-bound photosynthetic reaction centers upon illumination: a method to determine the photoexcitation rate.

    Science.gov (United States)

    Manzo, Anthony J; Goushcha, Alexander O; Barabash, Yuri M; Kharkyanen, Valery N; Scott, Gary W

    2009-07-01

    Kinetics of electron transfer, following variation of actinic light intensity, for photosynthetic reaction centers (RCs) of purple bacteria (isolated and membrane-bound) were analyzed by measuring absorbance changes in the primary photoelectron donor absorption band at 865 nm. The bleaching of the primary photoelectron donor absorption band in RCs, following a sudden increase of illumination from the dark to an actinic light intensity of I(exp), obeys a simple exponential law with the rate constant alphaI(exp) + k(rec), in which alpha is a parameter relating the light intensity, measured in mW/cm(2), to a corresponding theoretical rate in units of reciprocal seconds, and k(rec) is the effective rate constant of the charge recombination in the photosynthetic RCs. In this work, a method for determining the alpha parameter value is developed and experimentally verified for isolated and membrane-bound RCs, allowing for rigorous modeling of RC macromolecule dynamics under varied photoexcitation conditions. Such modeling is necessary for RCs due to alterations of the forward photoexcitation rates and relaxation rates caused by illumination history and intramolecular structural dynamics effects. It is demonstrated that the classical Bouguer-Lambert-Beer formalism can be applied for the samples with relatively low scattering, which is not necessarily the case with strongly scattering media or high light intensity excitation.

  12. Monolateral purple urine bag syndrome in a patient with bilateral nephrostomy tubes.

    Science.gov (United States)

    Sheehan, Michael

    2014-01-01

    Purple urine bag syndrome (PUBS) is a constellation of findings resulting in purple discoloration of the urine and/or urine drainage bag(s) occurring in patients with long-term urinary indwelling catheters. Other causative factors may include constipation, female gender, the presence of bacteria containing sulphatase and phosphatase enzymes, and alkaline urine. While the contributing factors for PUBS are linked with high morbidity, PUBS itself is a benign condition. A case study of monolateral PUBS in a patient with bilateral nephrostomy tubes (NTs) is presented.

  13. High-level production of the industrial product lycopene by the photosynthetic bacterium Rhodospirillum rubrum.

    Science.gov (United States)

    Wang, Guo-Shu; Grammel, Hartmut; Abou-Aisha, Khaled; Sägesser, Rudolf; Ghosh, Robin

    2012-10-01

    The biosynthesis of the major carotenoid spirilloxanthin by the purple nonsulfur bacterium Rhodospirillum rubrum is thought to occur via a linear pathway proceeding through phytoene and, later, lycopene as intermediates. This assumption is based solely on early chemical evidence (B. H. Davies, Biochem. J. 116:93-99, 1970). In most purple bacteria, the desaturation of phytoene, catalyzed by the enzyme phytoene desaturase (CrtI), leads to neurosporene, involving only three dehydrogenation steps and not four as in the case of lycopene. We show here that the chromosomal insertion of a kanamycin resistance cassette into the crtC-crtD region of the partial carotenoid gene cluster, whose gene products are responsible for the downstream processing of lycopene, leads to the accumulation of the latter as the major carotenoid. We provide spectroscopic and biochemical evidence that in vivo, lycopene is incorporated into the light-harvesting complex 1 as efficiently as the methoxylated carotenoids spirilloxanthin (in the wild type) and 3,4,3',4'-tetrahydrospirilloxanthin (in a crtD mutant), both under semiaerobic, chemoheterotrophic, and photosynthetic, anaerobic conditions. Quantitative growth experiments conducted in dark, semiaerobic conditions, using a growth medium for high cell density and high intracellular membrane levels, which are suitable for the conventional industrial production in the absence of light, yielded lycopene at up to 2 mg/g (dry weight) of cells or up to 15 mg/liter of culture. These values are comparable to those of many previously described Escherichia coli strains engineered for lycopene production. This study provides the first genetic proof that the R. rubrum CrtI produces lycopene exclusively as an end product.

  14. Elementary Energy Transfer Pathways in Allochromatium vinosum Photosynthetic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Lüer, Larry; Carey, Anne-Marie; Henry, Sarah; Maiuri, Margherita; Hacking, Kirsty; Polli, Dario; Cerullo, Giulio; Cogdell, Richard J.

    2015-11-01

    Allochromatium vinosum (formerly Chromatium vinosum) purple bacteria are known to adapt their light-harvesting strategy during growth according to environmental factors such as temperature and average light intensity. Under low light illumination or low ambient temperature conditions, most of the LH2 complexes in the photosynthetic membranes form a B820 exciton with reduced spectral overlap with LH1. To elucidate the reason for this light and temperature adaptation of the LH2 electronic structure, we performed broadband femtosecond transient absorption spectroscopy as a function of excitation wavelength in A. vinosum membranes. A target analysis of the acquired data yielded individual rate constants for all relevant elementary energy transfer (ET) processes. We found that the ET dynamics in high-light-grown membranes was well described by a homogeneous model, with forward and backward rate constants independent of the pump wavelength. Thus, the overall B800→B850→B890→ Reaction Center ET cascade is well described by simple triexponential kinetics. In the low-light-grown membranes, we found that the elementary backward transfer rate constant from B890 to B820 was strongly reduced compared with the corresponding constant from B890 to B850 in high-light-grown samples. The ET dynamics of low-light-grown membranes was strongly dependent on the pump wavelength, clearly showing that the excitation memory is not lost throughout the exciton lifetime. The observed pump energy dependence of the forward and backward ET rate constants suggests exciton diffusion via B850→ B850 transfer steps, making the overall ET dynamics nonexponential. Our results show that disorder plays a crucial role in our understanding of low-light adaptation in A. vinosum.

  15. Elementary Energy Transfer Pathways in Allochromatium vinosum Photosynthetic Membranes.

    Science.gov (United States)

    Lüer, Larry; Carey, Anne-Marie; Henry, Sarah; Maiuri, Margherita; Hacking, Kirsty; Polli, Dario; Cerullo, Giulio; Cogdell, Richard J

    2015-11-01

    Allochromatium vinosum (formerly Chromatium vinosum) purple bacteria are known to adapt their light-harvesting strategy during growth according to environmental factors such as temperature and average light intensity. Under low light illumination or low ambient temperature conditions, most of the LH2 complexes in the photosynthetic membranes form a B820 exciton with reduced spectral overlap with LH1. To elucidate the reason for this light and temperature adaptation of the LH2 electronic structure, we performed broadband femtosecond transient absorption spectroscopy as a function of excitation wavelength in A. vinosum membranes. A target analysis of the acquired data yielded individual rate constants for all relevant elementary energy transfer (ET) processes. We found that the ET dynamics in high-light-grown membranes was well described by a homogeneous model, with forward and backward rate constants independent of the pump wavelength. Thus, the overall B800→B850→B890→ Reaction Center ET cascade is well described by simple triexponential kinetics. In the low-light-grown membranes, we found that the elementary backward transfer rate constant from B890 to B820 was strongly reduced compared with the corresponding constant from B890 to B850 in high-light-grown samples. The ET dynamics of low-light-grown membranes was strongly dependent on the pump wavelength, clearly showing that the excitation memory is not lost throughout the exciton lifetime. The observed pump energy dependence of the forward and backward ET rate constants suggests exciton diffusion via B850→ B850 transfer steps, making the overall ET dynamics nonexponential. Our results show that disorder plays a crucial role in our understanding of low-light adaptation in A. vinosum.

  16. Automating the Purple Crow Lidar

    Directory of Open Access Journals (Sweden)

    Hicks Shannon

    2016-01-01

    Full Text Available The Purple Crow LiDAR (PCL was built to measure short and long term coupling between the lower, middle, and upper atmosphere. The initial component of my MSc. project is to automate two key elements of the PCL: the rotating liquid mercury mirror and the Zaber alignment mirror. In addition to the automation of the Zaber alignment mirror, it is also necessary to describe the mirror’s movement and positioning errors. Its properties will then be added into the alignment software. Once the alignment software has been completed, we will compare the new alignment method with the previous manual procedure. This is the first among several projects that will culminate in a fully-automated lidar. Eventually, we will be able to work remotely, thereby increasing the amount of data we collect. This paper will describe the motivation for automation, the methods we propose, preliminary results for the Zaber alignment error analysis, and future work.

  17. Automating the Purple Crow Lidar

    Science.gov (United States)

    Hicks, Shannon; Sica, R. J.; Argall, P. S.

    2016-06-01

    The Purple Crow LiDAR (PCL) was built to measure short and long term coupling between the lower, middle, and upper atmosphere. The initial component of my MSc. project is to automate two key elements of the PCL: the rotating liquid mercury mirror and the Zaber alignment mirror. In addition to the automation of the Zaber alignment mirror, it is also necessary to describe the mirror's movement and positioning errors. Its properties will then be added into the alignment software. Once the alignment software has been completed, we will compare the new alignment method with the previous manual procedure. This is the first among several projects that will culminate in a fully-automated lidar. Eventually, we will be able to work remotely, thereby increasing the amount of data we collect. This paper will describe the motivation for automation, the methods we propose, preliminary results for the Zaber alignment error analysis, and future work.

  18. Study on the prescription simplification of the compound Danshen transformed by the mixed photosynthetic bacteria%简化混合光合细菌转化复方丹参制剂处方

    Institute of Scientific and Technical Information of China (English)

    秦娟; 杨飞; 赵建滨; 杨官娥; 王慧敏; 张肇铭

    2011-01-01

    目的:研究简化混合光合细菌转化复方丹参制剂(Ⅳ)处方.方法:用高脂饲料建立高脂血症大鼠模型,以血脂康为阳性对照,比较丹参提取液(Ⅰ)、球形红细菌转化丹参制剂(Ⅱ)、球形红细菌(Ⅲ)及Ⅳ血脂、抗氧化能力和血液流变学指标.结果:Ⅰ、Ⅱ、Ⅳ组能显著降低高脂血症大鼠血清总胆固醇、甘油三脂、低密度脂蛋白水平( P<0.01,P<0.05),Ⅱ、Ⅲ组能显著提高高密度脂蛋白水平(P<0.05);Ⅱ、Ⅲ、Ⅳ能显著提高高脂血症大鼠谷胱甘肽过氧化物酶活力(P<0.01),Ⅰ-Ⅲ组能显著提高超氧化物歧化酶活力(P<0.01),Ⅰ、Ⅱ、Ⅳ组能显著降低丙二醛水平( P<0.01,P<0.05);Ⅰ-Ⅲ组能显著降低不同切变率下全血黏度(P<0.01),Ⅱ-Ⅳ组能有效降低血浆黏度(P<0.01),Ⅰ-Ⅳ组能有效降低红细胞压积(P<0.01).结论:Ⅱ综合降脂作用优于Ⅰ、Ⅲ、Ⅳ,可以作为混合光合细菌转化复方丹参制剂(Ⅳ)的简化处方.%Objective: To simplify the preparation prescription of the compound Danshen transformed by the mixed photosynthetic bacteria. Method: High-fat rat model was set up by feeding the high fat fodder. Xuezhikang as positive control, to compare the blood lipids, antioxidant capacity and hemorheology of Danshen extract liquid (I), Danshen transformed by Rhodobacter sphaeroides preparation (II), Rhodobacter sphaeroides culture solution (DI) and the compound Danshen transformed by the mixed photosynthetic bacteria preparation (IV) between them. Result: I, II, IV could significantly reduce the serum TC, TG, LDL-C levels (/><0.01), I-IV could significantly reduce the hematocrit (P<0.01). Conclusion: Comprehensive lowering lipids efficiency of II was superior to the other I, III, IV. II could be used as the simplified preparation of the IV.

  19. 离子液体中固定化光合细菌催化不对称还原反应的研究%Immobilized Photosynthetic Bacteria Asymmetric Reduction of Acetophenone in Ionic Liquid

    Institute of Scientific and Technical Information of China (English)

    王梦亮; 崔丙健

    2011-01-01

    采用苯乙酮为模式底物,选用了3种典型的离子液体作为反应介质系统研究了离子液体与缓冲液构成的均相及两相体系中固定化光合细菌催化不对称还原反应的特性.通过对构建的离子液体反应体系进行条件优化,发现与水相及有机相相比,离子液体作为生物催化反应介质更有利于还原反应的进行,并且离子液体及固定化细胞易回收重复利用.研究结果表明,在含15%体积分数的亲水性离子液体[EMIM][EtSO4]/缓冲液反应体系中,当底物苯乙酮浓度为35mmol/L时,在最佳的反应条件下,催化生成的产物主要是S-苯乙醇,产率和对映值分别达到82.7%和99.9%.离子液体不仅提高了催化反应速率,而且增加了固定化光合细菌的稳定性,为反应介质和生物催化剂的循环使用提供了保证.%Acetophenone was selected as the model substrate, and monophasic and biphasic ionic liquid/buffer reaction systems were built respectively through three typical ionic liquids. The systematic study to the reaction characteristics of immobilized photosynthetic bacteria has been inuestigated. Based on optimization of reaction conditions and systems, we found that the use of ionic liquids instead of conventional solvents give better results than aqueous phase and organic phase systems. Furthermore, ionic liquids and immobilized cells can be recycled. The results indicate that immobilized photosynthetic bacteria can catalyze acetophenone to product corresponding (S)-phenylethanol mainly under the optimised conditions, such as in hydrophilic ionic liquid [ EMIM ] [ EtSO4 ] with 15 % volume fraction as monophasic ionic liquid/buffer reaction system. The yield and the enantiomeric excess values (ee) of (S)-phenylethanol were 82.7% and up to 99%, respectively. Ionic liquids not only enhance the catalytic reaction rate, but also increase the stability of biocatalysts. The

  20. 光合细菌与纳豆菌的混合培养及混合处理养殖水的研究%Study on the Mixed Culture of Photosynthetic Bacteria with Bacillus Natto and its Effects on Aquaculture Water

    Institute of Scientific and Technical Information of China (English)

    唐婷; 陈济琛; 田燕丹; 林新坚; 邱宏端

    2015-01-01

    In order to make photosynthetic bacteria reached the maximum number of viable cells in the shortest possible time , , the culture inoculation and liquid volume of agents for the mixed culture of natto and photosynthetic bacteria were studied .with orthogonal test .The results showed that 20% of photosynthetic bacteria inoculation , natto inoculum 2% ,agent liquid volume 60% in 250 mL flask culture was the best .The effects of mixture culture of photosynthetic bacteria and natto bacteria on the degradation of nitrite nitrogen and ammonia nitrogen in aquaculture water were also studied .The results showed that the best effect was received when two kinds of bacteria was mixed at 1∶1 (v∶v) ,and the amount of mixed bacterial agents was positive correlation with the degradation of nitrite . Because natto bacteria could transfer organic nitrogen of medium into ammonia , so the increasing of the added amount of mixed inoculant weakened the degradation effects of ammonia nitrogen in aquaculture water .%采用正交试验优化纳豆菌和光合细菌混合培养时的接种量及菌剂的装液量,使光合细菌活菌数在最短的时间内达到最大值。结果显示:光合细菌接种量20%、纳豆菌接种量2%、每250mL三角瓶菌剂装液量60%培养效果最好。同时研究了光合细菌与纳豆菌混合菌剂对养殖水的亚硝酸盐氮以及氨氮的降解能力,发现2种菌的最佳混合比例为1∶1(v∶v),混合菌菌剂添加量与亚硝酸盐的降解作用成正相关;由于纳豆菌能将培养基中的有机氮转化为氨氮,混合菌剂对养殖水氨氮的降解效果随着添加量的增加而减弱。

  1. Statistical considerations on the formation of circular photosynthetic light-harvesting complexes from Rhodopseudomonas palustris.

    Science.gov (United States)

    Taniguchi, Masahiko; Henry, Sarah; Cogdell, Richard J; Lindsey, Jonathan S

    2014-07-01

    Depending on growth conditions, some species of purple photosynthetic bacteria contain peripheral light-harvesting (LH2) complexes that are heterogeneous owing to the presence of different protomers (containing different αβ-apoproteins). Recent spectroscopic studies of Rhodopseudomonas palustris grown under low-light conditions suggest the presence of a C 3-symmetric LH2 nonamer comprised of two distinct protomers. The software program Cyclaplex, which enables generation and data-mining of virtual libraries of molecular rings formed upon combinatorial reactions, has been used to delineate the possible number and type of distinct nonamers as a function of numbers of distinct protomers. The yield of the C 3-symmetric nonamer from two protomers (A and B in varying ratios) has been studied under the following conditions: (1) statistical, (2) enriched (preclusion of the B-B sequence), and (3) seeded (pre-formation of an A-B-A block). The yield of C 3-symmetric nonamer is at most 0.98 % under statistical conditions versus 5.6 % under enriched conditions, and can be dominant under conditions of pre-seeding with an A-B-A block. In summary, the formation of any one specific nonamer even from only two protomers is unlikely on statistical grounds but must stem from enhanced free energy of formation or a directed assembly process by as-yet unknown factors.

  2. (Carbon monoxide metabolism by photosynthetic bacteria)

    Energy Technology Data Exchange (ETDEWEB)

    1989-01-01

    Research continued on the metabolism of carbon monoxide by Rhodospirillum rubrum. This report discusses progress on the activity, induction, inhibition, and spectroscopic analysis of the enzyme Carbon Monoxide Dehydrogenase. (CBS)

  3. Chlorosomes: antenna organelles in photosynthetic green bacteria

    DEFF Research Database (Denmark)

    Frigaard, N.-U.; Bryant, D. A.

    2006-01-01

    that cover the spectrum of the complex intracellular structures of prokaryotes: proteasomes, phycobilisomes, chlorosomes, gas vesicles, carboxysomes, magnetosomes, intracytoplasmic membranes, membrane-bound nucleoids, anammoxosomes, and cytoarchitecture of Epulopiscium spp. Cameos of selected additional......The new series "Microbiology Monographs" begins with two volumes on intracellular components in prokaryotes. In this second volume, "Complex Intracellular Structures in Prokaryotes", the components, labelled complex intracellular structures, encompass a multitude of important cellular functions....... Continuing and newly initiated research will provide a clearer understanding of the complex intracellular structures known at present and will bring to light surprising new ones as well. "Complex Intracellular Structures in Prokaryotes" provides historical background and comprehensive reviews of ten topics...

  4. Chlorosomes: antenna organelles in photosynthetic green bacteria

    DEFF Research Database (Denmark)

    Frigaard, N.-U.; Bryant, D. A.

    2006-01-01

    The new series "Microbiology Monographs" begins with two volumes on intracellular components in prokaryotes. In this second volume, "Complex Intracellular Structures in Prokaryotes", the components, labelled complex intracellular structures, encompass a multitude of important cellular functions. ...

  5. 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.

  6. Primary arsenic(V) preserved in 3.26 billion-year-old shallow marine cherts of the Fig Tree Group demonstrates a complete Paleoarchean arsenic cycle driven by photosynthetic bacteria

    Science.gov (United States)

    Myers, K. D.; Tice, M. M.; Bostick, B. C.

    2016-12-01

    reduction potential than the Fe(III)/Fe(II) pair, and As(V) is not produced in significant abundance by photochemical processes at seawater pH. The Fig Tree As cycle must therefore have been driven by photosynthetic bacteria, either indirectly through O2 production, or more likely directly by As(III)-oxidizing anoxygenic phototrophs.

  7. The 2-Methoxy Group Orientation Regulates the Redox Potential Difference between the Primary (QA) and Secondary (QB) Quinones of Type II Bacterial Photosynthetic Reaction Centers

    Science.gov (United States)

    2015-01-01

    Recent studies have shown that only quinones with a 2-methoxy group can act simultaneously as the primary (QA) and secondary (QB) electron acceptors in photosynthetic reaction centers from purple bacteria such as Rb. sphaeroides. 13C HYSCORE measurements of the 2-methoxy group in the semiquinone states, SQA and SQB, were compared with DFT calculations of the 13C hyperfine couplings as a function of the 2-methoxy dihedral angle. X-ray structure comparisons support 2-methoxy dihedral angle assignments corresponding to a redox potential gap (ΔEm) between QA and QB of 175–193 mV. A model having a methyl group substituted for the 2-methoxy group exhibits no electron affinity difference. This is consistent with the failure of a 2-methyl ubiquinone analogue to function as QB in mutant reaction centers with a ΔEm of ∼160–195 mV. The conclusion reached is that the 2-methoxy group is the principal determinant of electron transfer from QA to QB in type II photosynthetic reaction centers with ubiquinone serving as both acceptor quinones. PMID:25126386

  8. The 2-Methoxy Group Orientation Regulates the Redox Potential Difference between the Primary (QA) and Secondary (QB) Quinones of Type II Bacterial Photosynthetic Reaction Centers.

    Science.gov (United States)

    de Almeida, Wagner B; Taguchi, Alexander T; Dikanov, Sergei A; Wraight, Colin A; O'Malley, Patrick J

    2014-08-07

    Recent studies have shown that only quinones with a 2-methoxy group can act simultaneously as the primary (QA) and secondary (QB) electron acceptors in photosynthetic reaction centers from purple bacteria such as Rb. sphaeroides. (13)C HYSCORE measurements of the 2-methoxy group in the semiquinone states, SQA and SQB, were compared with DFT calculations of the (13)C hyperfine couplings as a function of the 2-methoxy dihedral angle. X-ray structure comparisons support 2-methoxy dihedral angle assignments corresponding to a redox potential gap (ΔEm) between QA and QB of 175-193 mV. A model having a methyl group substituted for the 2-methoxy group exhibits no electron affinity difference. This is consistent with the failure of a 2-methyl ubiquinone analogue to function as QB in mutant reaction centers with a ΔEm of ∼160-195 mV. The conclusion reached is that the 2-methoxy group is the principal determinant of electron transfer from QA to QB in type II photosynthetic reaction centers with ubiquinone serving as both acceptor quinones.

  9. Proteomic analysis of the purple sulfur bacterium Candidatus "Thiodictyon syntrophicum" strain Cad16T isolated from Lake Cadagno

    DEFF Research Database (Denmark)

    Storelli, Nicola; Saad, Maged M.; Frigaard, Niels-Ulrik

    2014-01-01

    Lake Cadagno is characterised by a compact chemocline with high concentrations of purple sulfur bacteria (PSB). 2D-DIGE was used to monitor the global changes in the proteome of Candidatus "Thiodictyon syntrophicum" strain Cad16T both in the presence and absence of light. This study aimed...

  10. Proteomic analysis of the purple sulfur bacterium Candidatus "Thiodictyon syntrophicum" strain Cad16T isolated from Lake Cadagno

    DEFF Research Database (Denmark)

    Storelli, Nicola; Saad, Maged M.; Frigaard, Niels-Ulrik;

    2014-01-01

    Lake Cadagno is characterised by a compact chemocline with high concentrations of purple sulfur bacteria (PSB). 2D-DIGE was used to monitor the global changes in the proteome of Candidatus "Thiodictyon syntrophicum" strain Cad16T both in the presence and absence of light. This study aimed...

  11. Purple%颜色文化——紫色

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Royalty and Spirituality 高贵与信仰 Purple is royalty. A mysterious color, purple is associated with both nobility and spirituality. The opposites of hot red and cool blue combine to create this intriguing color.

  12. The anti-photooxidation of anthocyanins-rich leaves of a purple rice cultivar

    Institute of Scientific and Technical Information of China (English)

    PENG Changlian; LIN Guizhu; LIN Zhifang; CHEN Shaowei

    2006-01-01

    In the leaf of rice (Oryza sativa L.) cultivar Yunnan purple rice, the anthocyanins with an obvious absorption peak at 530nm were distributed in the cells of upper and lower epidermis, bulliform tissue and bristle. The maximal photosynthetic oxygen evolution rate and chlorophyll content in flag leaves were 28% and 23%, respectively, more than the common green leaf rice cultivar Chijiaoruanzhan. Higher chlorophyll content is probably one of the physiological adaptations for enhancing light harvesting capacity of the antenna in photosystems in this cyanic leaves species. Upon the photooxidation of leaf segments mediated by methyl viologen in weak light for 3 days, the distinct bleaching of anthocyanins in purple rice was associated with the reduction of scavenging ability to DPPH· free radical ability and the increase in membrane leakage rate. But almost no changes in contents of flavonoids and total phenolics were observed. Chlorophyll fluorescence parameters Fv/Fo, qP and фPSII decreased with the increase in NPQ and DES of xanthophylls cycle after photooxidation treatment. Green rice leaves showed more decrease in DPPH· scavenging rate and more increase in cell membrane leakage rate but showed a trace of anthocyanins during photooxidation. It is suggested that anthocyanin may be a beneficial and primary antioxidant in sun cyanic rice leaves against oxidative stress induced by environmental adversity. And photooxidation could induce different changing patterns of anthocyanins between the tested purple and green rice leaves.

  13. Microbial characteristics of purple paddy soil in response to Pb pollution.

    Science.gov (United States)

    Jiang, Qiu-Ju; Zhang, Yue-Qiang; Zhang, La-Mei; Zhou, Xin-Bin; Shi, Xiao-Jun

    2014-05-01

    The study focused on the change of microbial characteristics affected by Plumbum pollution with purple paddy soil in an incubation experiment. The results showed that low concentration of Plumbum had little effect on most of microbial amounts, biological activity and enzymatic activity. However, denitrifying activity was inhibited severely, and inhibition rate was up to 98%. Medium and high concentration of Plumbum significantly reduced the amounts and activity of all microorganisms and enzymatic activity, which increased with incubation time. Negative correlations were found between Plumbum concentrations and microbial amounts, biological activity and enzymatic activities except fungi and actinomyces. Thus they can be used to indicate the Plumbum pollution levels to some extent. LD(50) of denitrifying bacteria (DB) and ED50 of denitrifying activity were 852mg/kg and 33.5mg/kg. Across all test soil microbes, denitrifying bacteria was most sensitive to Plumbum pollution in purple paddy soil. Value of early warning showed that anaerobic cellulose-decomposing bacteria (ACDB) and actinomyces were also sensitive to Plumbum pollution. We concluded that denitrifying activity, actinomyces, ACDB or DB can be chosen as predictor of Plumbum contamination in purple paddy soil.

  14. Topology and energy transport in networks of interacting photosynthetic complexes

    CERN Document Server

    Allegra, Michele

    2012-01-01

    We take inspiration from light-harvesting networks present in purple bacteria and simulate an incoherent dissipative energy transfer process on more general and abstract networks, considering both regular structures (Cayley trees and hyperbranched fractals) and randomly-generated ones. We focus on the the two primary light harvesting complexes of purple bacteria, i.e. the LH1 and LH2, and we use network-theoretical centrality measures in order to select different LH1 arrangements. We show that different choices cause significant differences in the transport efficiencies, and that for regular networks centrality measures allow to identify arrangements that ensure transport efficiencies which are better than those obtained with a random disposition of the complexes. The optimal arrangements strongly depend on the dissipative nature of the dynamics and on the topological properties of the networks considered, and depending on the latter they are achieved by using global vs. local centrality measures. Finally, we...

  15. Assembly of Photosynthetic Antenna Protein Complexes from Algae for Development of Nano-biodevice and Its Fuelization

    Science.gov (United States)

    2013-05-20

    Task 1 : Artificial domain assembly of LH pigment complexes from photosynthetic bacterial membranes on nano-patterning and lipid modified...public release; distribution unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT The purpose of this proposal is to use photosynthetic antenna pigment ...nanobiophotonics) and its fuelization. The advantage of these pigment complexes from algae as well as from plants and photosynthetic bacteria is its

  16. Photoluminescence of Turkish purple jade (turkiyenite)

    Energy Technology Data Exchange (ETDEWEB)

    Hatipoglu, Murat, E-mail: murat.hatipoglu@deu.edu.tr [Dokuz Eyluel University, IMYO, Izmir Multidisciplinary Vocational School, Gemmology and Jewellery Programme, TR-35380 Buca-Izmir (Turkey); Dokuz Eyluel University, The Graduate School of Natural and Applied Sciences, Department of Natural Building Stones and Gem Stones, TR-35370 Buca-Izmir (Turkey); Basevirgen, Yasemin [Dokuz Eyluel University, IMYO, Izmir Multidisciplinary Vocational School, Gemmology and Jewellery Programme, TR-35380 Buca-Izmir (Turkey); Dokuz Eyluel University, The Graduate School of Natural and Applied Sciences, Department of Natural Building Stones and Gem Stones, TR-35370 Buca-Izmir (Turkey)

    2012-11-15

    The purple-colored unique gem material is only found in the Harmanc Latin-Small-Letter-Dotless-I k (Bursa) region of the western Anatolia (Turkey). Therefore, it is specially called 'Turkish purple jade or turkiyenite' on the worldwide gem market. Even though its jadeite implication is the principal constituent, the material cannot be considered as a single jadeite mineral since other implications are quartz, orthoclase, epidote, chloritoid and phlogopite minerals. Even if the analytical methods are used to characterize and identify the Turkish purple jade samples in detail, the luminescence spectra, especially photoluminescence features regarding to composite mineral implications of the material are important because of the existence the numerous characteristic broad and intensive luminescence bands in the samples. We can state that the UV-irradiation luminescence centers as photoluminescence (PL) are due to the overall signals in the Turkish purple jade samples. Accordingly, the distinctive photoluminescence peaks at 743, 717, 698, 484, 465 and 442 nm in PL-2D (counter diagram and sections) and PL-3D (sequence spectra) ranging between 300 and 900 nm of wavelengths, and between 220 and 340 K of temperatures are observed. Finally, photoluminescence features of the heterogeneous-structured material cannot be simply attributed to any chemical impurities, since the jade mass has numerous heterogeneous mineral constituents instead of a single jadeite mineral. Six different mineral implications and chemical impurities in the material composition display complex and individual all kind of luminescence features. Therefore, photoluminescence as well as radioluminescence, cathodoluminescence and thermoluminescence spectra provide positive identification regarding to the provenance (geographic origin) of the original Turkish purple jade (turkiyenite). - Highlights: Black-Right-Pointing-Pointer The purple-colored gem material is only found in the Harmanc Latin

  17. THE EFFECT OF PHOTOSYNTHETIC BACTERIA ON AQUATIC ECOSYSTEM OF CARPS PRODUCTION%光合细菌对鲤养殖水体生态系统的影响

    Institute of Scientific and Technical Information of China (English)

    王梦亮; 马清瑞; 梁生康

    2001-01-01

    @@光合细菌(Photosynthetic Bacteria,简称PSB)是一种不放氧光合作用的细菌总称,近年来,光合细菌在理论和应用上都受到了广泛的重视,一方面由于它是研究光合作用的理想材料,另一方面,它又有广泛的应用价值。光合细菌在处理高浓度有机废水,生产单细胞蛋白,水产养殖和禽畜饲养,改善植物营养状况等方面已有不少报道[1—4],本文研究了光合细菌在鲤养殖水体中的增殖和分布规律以及它对水体中异养细菌、浮游动物及水质的影响,以阐明光合细菌在该生态系统中的作用。 1 材料与方法 1.1 光合细菌:由山西大学生命科学系提供,为沼泽红假单胞菌(Rhodopseudomonas palustris)和类球红细菌(Rhodopseudomonas sphaeroides)纯培养物1∶1的混合物,pH7.5,活菌数1.6×109个/mL。30kg/hm2一次洒入鱼塘。 1.2 实验地点:山西省原平市鱼场,养殖面积4hm2,共20个池塘,池塘平均水深2.5m 1.3 采样方法:从7月10日至8月20日平均每隔7d分别从对照池和实验池中各采样一次,然后进行光合细菌、异养细菌、浮游动物计数,待光合细菌大量增殖并趋于稳定时取样进行水质分析。共采样6次,采样用采水瓶分别取表层水(水面以下30cm)和底层水(水面以下2m)两种。 1.4 光合细菌计数方法:改良Ormerod培养基[5]MPN五管法计数,在牛肉膏蛋白胨培养基中,好氧菌采用稀释平板法计数,厌氧菌采用厌氧琼脂管,上加石腊隔氧法计数,培养温度30℃。

  18. The improvement of N-ammonia degradation of photosynthetic bacteria by protoplast fusion%采用原生质体融合技术选育提高氨氮降解效能的光合细菌

    Institute of Scientific and Technical Information of China (English)

    纪敦敦; 邱宏端; 谢航

    2011-01-01

    将高效降解氨氮的假丝酵母菌Candida sp.与高效降解亚硝酸盐氮的耐盐红螺菌Rhodaspeudomonas capsulate进行原生质体融合,探讨原生质体制备及融合的条件,并对融合子进行了筛选.结果表明,原生质体制备的优化条件如下:耐盐红螺菌,溶菌酶量为1.5 mg/mL,EDTA浓度为0.1 g/L,作用时间为45min;假丝酵母菌,蜗牛酶量为0.5 mg/mL,巯基乙醇的质量分数为0.1%,EDTA浓度为1g/L,作用时间为30 min.两种原生质体在聚乙二醇(PEG- 6000)和Ca2+的诱导下发生融合,在添加制霉菌素和链霉素的选择培养基上进行初筛,以生长稳定性及对氨氮、亚硝酸盐氮的降解效能等为指标进行复筛,获得了具有较好降解效能的融合子R1菌株.该菌株对亚硝酸盐氮的降解效能与耐盐红螺菌相同,达到90%以上;对氨氮的降解效能为63%,较耐盐红螺菌提高54%.%A protoplast fusion was conducted between two efficient photosynthetic bacteria, N-ammonia degrading Candida sp. And N-nitrite degrading Rhodospeudomonas capsulate. The conditions of the protoplast formation and fusion were optimized, and the best fusant was selected. The better protoplast formation for Rhodospeudomonas cap-sulata was found under the conditions of; lysozyme at 1.5 mg/mL, EDTA 0.1g/L and 45 min reaction time; for Candida sp. The better conditions of snail enzyme at 0.5 mg/mL, mercaptoethanol 0.1% ,EDTA 1 g/L and 30 min reaction time. The fusion was induced by PEG 6000 and Ca2+. Fusants were screened out by selective media containing added nystatin and streptomycin. The fusant R1 with better efficient degradation was selected by growth stability and degradation. The fusant Rl showed N -nitrite degradation at a rate of more than 90% , as good as for Rhodospeudomonas capsulata, but had N-ammonia degradation of only 63% , increased by 54%.

  19. Purple coneflower viruses: species diversity and harmfulness

    Directory of Open Access Journals (Sweden)

    Dunich A. A.

    2015-02-01

    Full Text Available Viral diseases became an actual problem in medicinal plants cultivation. The number of viruses known to infect purple coneflower increased significantly in the last years in many countries. However, there is no any review about the viral diseases of this valuable medicinal crop. Therefore, the aim of this article is to summarize the main information about the viruses affecting purple coneflower plants (Echinacea purpurea L. Moench.. An analysis of the literature data showed that purple coneflower could be infected by 10 viruses. These viruses belong to the families Bromoviridae, Bunyaviridae, Secoviridae, Potyviridae, Vir­ga­vi­ri­dae, and almost all of them are considered to be highly harmful plant viruses. Additionally, four of them (TMV, TSWV, CMV, PVY are in the top 10 of the most economically important plant viruses in the world and occupy the first places. Such distribution and harmfulness of these viruses are explained by a wide range of sensitive host-plants, wild plants and weeds – reservoirs of an infection, and also a large number of vectors. The data from a few countries show that the viral diseases of purple coneflower are becoming more severe from year to year. The appearance of new viruses is registered on coneflower every year that complicates prognosis and risk estimation of epiphytoties in these regions which, for example, were revealed in Bulgaria, Lithuania and Ukraine. This review presents the detailed symptoms of the viral diseases in purple coneflower, the main properties of each virus and data about their harmful effect on the quality of raw material (the concentration of biologically active substances and heavy metals in plants.

  20. Research on yogurt with purple potato%紫薯酸奶的研制

    Institute of Scientific and Technical Information of China (English)

    陈丹瑾; 程缘; 韩翠萍; 刘玲; 崔娜; 李刚; 王楠楠

    2012-01-01

    With fresh milk, fresh purple sweet potato as the main raw material, add streptococcus thermophilus and Bulgaria coli to make yogurt-Processing condition of the yogurt mixed purple sweet potato were studied. By single—factor test and orthogonal test to determine the optimal technological parameters of the production of purple sweet potato yogurt. Results show that the optimal fermentation parameters as: ratio of purple sweet potato and fresh milk is 1:4, inoculum is 4%, fermentation temperature is 37 ℃, fermentation time is 12 h, the amount of sugar added to 9%.Under the condition, the yogurt is lavender, uniform texture, aroma and rich, with a purple sweet potato lactic add bacteria fermented yoghurt aroma. The yogurt has a sweet and delicious taste with delicate, soft.%以鲜牛奶,新鲜紫薯为主要原料,添加嗜热链球菌和保加利亚乳杆菌,研究搅拌型紫薯酸奶的加工工艺条件.通过单因素试验和正交试验确定制作紫薯酸奶的最佳工艺参数.结果表明,紫薯与鲜牛奶的比例为1∶4,接种量为4%,发酵温度37℃,发酵时间为12 h,白砂糖添加量为9%.此条件下制作的酸奶呈淡紫色,质地均匀一致,具有紫薯和浓郁的乳酸菌发酵酸奶的香味,酸甜可口,口感细腻,柔和.

  1. Resonance Raman studies of the purple membrane.

    Science.gov (United States)

    Aton, B; Doukas, A G; Callender, R H; Becher, B; Ebrey, T G

    1977-06-28

    The individual resonance Raman spectra of the PM568 and M412 forms of light-adapted purple membrane from Halobacterium halobium have been measured using the newly developed flow technique. For comparison purposes, the Raman spectra of the model chromophores, all-trans- and 13-cis retinal n-butylamine, both as protonated and unprotonated Schiff bases, have also been obtained. In agreement with previous work, the Raman data indicate that the retinal chromophore is linked to the purple membrane protein via a protonated. Schiff base in the case of the PM568 and an unprotonated Schiff base for the M412 form. The basic mechanism for color regulation in both forms appears to be electron delocalization. The spectral features of the two forms are different from each other and different from the model compound spectra.

  2. The Female Bonding in The Color Purple

    Institute of Scientific and Technical Information of China (English)

    余跃

    2007-01-01

    This paper aims at a survey of the female bonding in The Color Purple,which plays an important role in the heroine's finding her voice and sense of self.By examining the black women's struggle to explore their identity and claim their selves under sexual and racial oppressions,Alice Walker,the author,shows her understanding of the process that black women must undergo to achieve their vision.

  3. Photosynthetic reaction centers/ITO hybrid nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Szabo, Tibor [Department of Medical Physics and Informatics, University of Szeged, Szeged (Hungary); Bencsik, Gabor [Department of Physical Chemistry and Materials Science, University of Szeged, Szeged (Hungary); Magyar, Melinda [Department of Medical Physics and Informatics, University of Szeged, Szeged (Hungary); Visy, Csaba [Department of Physical Chemistry and Materials Science, University of Szeged, Szeged (Hungary); Gingl, Zoltan [Department of Technical Informatics, University of Szeged, Szeged (Hungary); Nagy, Krisztina; Varo, Gyoergy [Institute of Biophysics, Hungarian Academy of Sciences, Biological Research Center, Szeged (Hungary); Hajdu, Kata; Kozak, Gabor [Department of Medical Physics and Informatics, University of Szeged, Szeged (Hungary); Nagy, Laszlo, E-mail: lnagy@sol.cc.u-szeged.hu [Department of Medical Physics and Informatics, University of Szeged, Szeged (Hungary)

    2013-03-01

    Photosynthetic reaction center proteins purified from Rhodobacter sphaeroides purple bacterium were deposited on the surface of indium tin oxide (ITO), a transparent conductive oxide, and the photochemical/-physical properties of the composite were investigated. The kinetics of the light induced absorption change indicated that the RC was active in the composite and there was an interaction between the protein cofactors and the ITO. The electrochromic response of the bacteriopheophytine absorption at 771 nm showed an increased electric field perturbation around this chromophore on the surface of ITO compared to the one measured in solution. This absorption change is associated with the charge-compensating relaxation events inside the protein. Similar life time, but smaller magnitude of this absorption change was measured on the surface of borosilicate glass. The light induced change in the conductivity of the composite as a function of the concentration showed the typical sigmoid saturation characteristics unlike if the photochemically inactive chlorophyll was layered on the ITO. In this later case the light induced change in the conductivity was oppositely proportional to the chlorophyll concentration due to the thermal dissipation of the excitation energy. The sensitivity of the measurement is very high; few picomole RC can change the light induced resistance of the composite. - Highlights: Black-Right-Pointing-Pointer Photosynthetic reaction center/ITO nanocomposite has been fabricated. Black-Right-Pointing-Pointer The composite showed photochemical/-physical activity with very high sensitivity. Black-Right-Pointing-Pointer This new type of material can be a good model of optoelectronic devices.

  4. Investigation on antimicrobial effects of essential oil of purple coneflower (Echinacea purpurea L. and identification of its chemical compounds

    Directory of Open Access Journals (Sweden)

    Zahra Izadi

    2014-04-01

    Full Text Available Background: Purple coneflower (Echinaceae purpurea L. is a perennial herbaceous with astringent properties, disinfectant, antimicrobial and anti intoxication activity. The main objective of this study was to evaluate the antimicrobial activity of shoot essential oil of purple coneflower against some microorganisms including gram positive, gram negative bacteria, filamentous fungi and yeasts. Material and Methods: In this experimental and laboratory investigation, plant samples were collected in full blooming stage. Shoot essential oil was extracted by hydro-distillation technique using Clevenger apparatus. The chemical constitutes of this oil was analyzed by GC and GC/MS method. Anti microbial properties of the essential oil were determined using micro broth dilution and well disk diffusion methods. At the end, data were analyzed by the SPSS version 15 software, using the T-test and Duncan s' test. Results: Twenty nine components were identified by GC and GC/MS in the essential oil of purple coneflower representing 96.21% of total oil. The major components were Germacrene D (53.30%, -Cymene (9.78%, β-Caryophyllene (7.52%, α-Humulene (5.22%, β-Bisabolene (4.43% and α-Pinene (4.23%, respectively. This oil exhibited strong antifungal activity against filamentous fungi and yeast with average of inhibition zone (AIZ 39.63. Microorganisms differ in their resistance to purple coneflower oil. All of the bacteria including gram positive and gram negative bacteria are more resistant than fungi and gram negative bacteria are more resistant than gram positive bacteria. Pseudomonas aeruginosa and Salmonella typhimurium were more resistant than others. Conclusion: The results of this study showed that coneflower essential oil with significant antimicrobial effects and can be used instead of synthetic antibiotics that microbial resistance towards them is increasing.

  5. Photosynthetic Diurnal Variation of Soybean Cultivars with High Photosynthetic Efficiency

    Institute of Scientific and Technical Information of China (English)

    MAN Wei-qun; DU Wei-guang; ZHANG Gui-ru; LUAN Xiao-yan; GE Qiao-ying; HAO Nai-bin; CHEN Yi

    2002-01-01

    The photosynthetic characters were investigated among soybean cultivars with high photosynthetic efficiency and high yield. The results indicated that: 1) There were significant differences in photosynthetic rate (Ph) and dark respiration rate (DR) under saturation light intensity and appropriate temperature.2) There were a little difference in light compensation point among them. Photo flux density (PFD) were mong the cultivars. Diurnal variation of Pn was shown a curve with two peaks. 4) The cultivars with high photosynthetic efficiency were subjected less to photoinhibition than that with high yield. Critical temperatures of photoinhibition in high photosynthetic efficiency cultivars were higher than that of high yield.

  6. Model for transport of glucose across membrane and production of hydrogen by photosynthetic bacteria%光合细菌的葡萄糖跨膜传输及代谢产氢模型

    Institute of Scientific and Technical Information of China (English)

    谢学旺; 董舟; 朱恂; 廖强

    2012-01-01

    Based on single photosynthetic bacterial cell in a batch reactor for bio-production of H2, a model was established for transport of glucose across membrane and production of hydrogen. The concentration distribution of glucose and hydrogen in the bioreactor was estimated, and the effect of light wavelength and intensity on glucose concentration in outside of cells as well as concentration profiles of hydrogen was investigated. The results showed that substantial agreement was achieved between the experimental results and model prediction values; and at wavelength and intensity of light 590 nm and 8000 lx respectively, the concentration of glucose was the lowest, and concentration of hydrogen was the highest outside cells.

  7. Proposal to consistently apply the International Code of Nomenclature of Prokaryotes (ICNP) to names of the oxygenic photosynthetic bacteria (cyanobacteria), including those validly published under the International Code of Botanical Nomenclature (ICBN)/International Code of Nomenclature for algae, fungi and plants (ICN), and proposal to change Principle 2 of the ICNP.

    Science.gov (United States)

    Pinevich, Alexander V

    2015-03-01

    This taxonomic note was motivated by the recent proposal [Oren & Garrity (2014) Int J Syst Evol Microbiol 64, 309-310] to exclude the oxygenic photosynthetic bacteria (cyanobacteria) from the wording of General Consideration 5 of the International Code of Nomenclature of Prokaryotes (ICNP), which entails unilateral coverage of these prokaryotes by the International Code of Nomenclature for algae, fungi, and plants (ICN; formerly the International Code of Botanical Nomenclature, ICBN). On the basis of key viewpoints, approaches and rules in the systematics, taxonomy and nomenclature of prokaryotes it is reciprocally proposed to apply the ICNP to names of cyanobacteria including those validly published under the ICBN/ICN. For this purpose, a change to Principle 2 of the ICNP is proposed to enable validation of cyanobacterial names published under the ICBN/ICN rules. © 2015 IUMS.

  8. Photosynthetic CO{sub 2} fixation and energy production - microalgae as a main subject

    Energy Technology Data Exchange (ETDEWEB)

    Asada, Yasuo [National Inst. of Bioscience and Human-Technology, Tsukuba-shi, Ibaraki-ken (Japan)

    1993-12-31

    Research activities for application of microalgal photosynthesis to CO{sub 2} fixation in Japan are overviewed. Presenter`s studies on energy (hydrogen gas) production by cyanobacteria (blue-green algae) and photosynthetic bacteria are also introduced.

  9. Development of biomarkers and a diagnostic tool for investigation of coinfections by and interactions between potato purple top and potato witches’-broom phytoplasmas in tomato

    Science.gov (United States)

    Columbia Basin potato purple top (PPT) phytoplasma and Alaska potato witches’-broom (PWB) phytoplasma are two closely-related but mutually distinct pathogenic bacteria that infect potato and other vegetable crops. Inhabiting phloem sieve elements and being transmitted by phloem-feeding insect vecto...

  10. Photosynthetic Pigments in Diatoms

    OpenAIRE

    Paulina Kuczynska; Malgorzata Jemiola-Rzeminska; Kazimierz Strzalka

    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...

  11. Evolving a photosynthetic organelle

    Directory of Open Access Journals (Sweden)

    Nakayama Takuro

    2012-04-01

    Full Text Available Abstract The evolution of plastids from cyanobacteria is believed to represent a singularity in the history of life. The enigmatic amoeba Paulinella and its 'recently' acquired photosynthetic inclusions provide a fascinating system through which to gain fresh insight into how endosymbionts become organelles. The plastids, or chloroplasts, of algae and plants evolved from cyanobacteria by endosymbiosis. This landmark event conferred on eukaryotes the benefits of photosynthesis - the conversion of solar energy into chemical energy - and in so doing had a huge impact on the course of evolution and the climate of Earth 1. From the present state of plastids, however, it is difficult to trace the evolutionary steps involved in this momentous development, because all modern-day plastids have fully integrated into their hosts. Paulinella chromatophora is a unicellular eukaryote that bears photosynthetic entities called chromatophores that are derived from cyanobacteria and has thus received much attention as a possible example of an organism in the early stages of organellogenesis. Recent studies have unlocked the genomic secrets of its chromatophore 23 and provided concrete evidence that the Paulinella chromatophore is a bona fide photosynthetic organelle 4. The question is how Paulinella can help us to understand the process by which an endosymbiont is converted into an organelle.

  12. A simple evaluation of soil quality of waterlogged purple paddy soils with different productivities.

    Science.gov (United States)

    Liu, Zhanjun; Zhou, Wei; Lv, Jialong; He, Ping; Liang, Guoqing; Jin, Hui

    2015-01-01

    Evaluation of soil quality can be crucial for designing efficient farming systems and ensuring sustainable agriculture. The present study aimed at evaluating the quality of waterlogged purple paddy soils with different productivities in Sichuan Basin. The approach involved comprehensive analyses of soil physical and chemical properties, as well as enzyme activities and microbial community structure measured by phospholipid fatty acid analysis (PLFA). A total of 36 soil samples were collected from four typical locations, with 12 samples representing high productivity purple paddy soil (HPPS), medium productivity purple paddy soil (MPPS) and low productivity purple paddy soil (LPPS), respectively. Most measured soil properties showed significant differences (P ≤ 0.05) among HPPS, MPPS and LPPS. Pearson correlation analysis and principal component analysis were used to identify appropriate soil quality indicators. A minimum data set (MDS) including total nitrogen (TN), available phosphorus (AP), acid phosphatase (ACP), total bacteria (TB) and arbuscular mycorrhizal fungi was established and accounted for 82.1% of the quality variation among soils. A soil quality index (SQI) was developed based on the MDS method, whilst HPPS, MPPS and LPPS received mean SQI scores of 0.725, 0.536 and 0.425, respectively, with a ranking of HPPS > MPPS > LPPS. HPPS showed relatively good soil quality characterized by optimal nutrient availability, enzymatic and microbial activities, but the opposite was true of LPPS. Low levels of TN, AP and soil microbial activities were considered to be the major constraints limiting the productivity in LPPS. All soil samples collected were rich in available N, K, Si and Zn, but deficient in available P, which may be the major constraint for the studied regions. Managers in our study area should employ more appropriate management in the LPPS to improve its rice productivity, and particularly to any potential limiting factor.

  13. Coordinated, long-range, solid substrate movement of the purple photosynthetic bacterium Rhodobacter capsulatus.

    Directory of Open Access Journals (Sweden)

    Kristopher John Shelswell

    Full Text Available The long-range movement of Rhodobacter capsulatus cells in the glass-agar interstitial region of borosilicate Petri plates was found to be due to a subset of the cells inoculated into plates. The macroscopic appearance of plates indicated that a small group of cells moved in a coordinated manner to form a visible satellite cluster of cells. Satellite clusters were initially separated from the point of inoculation by the absence of visible cell density, but after 20 to 24 hours this space was colonized by cells apparently shed from a group of cells moving away from the point of inoculation. Cell movements consisted of flagellum-independent and flagellum-dependent motility contributions. Flagellum-independent movement occurred at an early stage, such that satellite clusters formed after 12 to 24 hours. Subsequently, after 24 to 32 hours, a flagellum-dependent dispersal of cells became visible, extending laterally outward from a line of flagellum-independent motility. These modes of taxis were found in several environmental isolates and in a variety of mutants, including a strain deficient in the production of the R. capsulatus acyl-homoserine lactone quorum-sensing signal. Although there was great variability in the direction of movement in illuminated plates, cells were predisposed to move toward broad spectrum white light. This predisposition was increased by the use of square plates, and a statistical analysis indicated that R. capsulatus is capable of genuine phototaxis. Therefore, the variability in the direction of cell movement was attributed to optical effects on light waves passing through the plate material and agar medium.

  14. Progress in Research of Bacteria Fertilizer Strengthening Resistance of Plants

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Bacteria fertilizer is used most widely among all kinds of microbial fertilizers. We summarize the research headway of bacteria fertilizer. It mainly focuses on bacteria fertilizer improving the stress resistance of plant. Then we can offer basis to research and exploit bacteria fertilizer. These bacteria include azotobacter, photosynthetic bacteria, Bacillus mucilaginosus siliceous, phosphorus bacteria, plant growth-promoting rhizobacteria(PGPR), effective microorganism(EM).

  15. Symbolic Significance of Colors in the Novel The Color Purple

    Institute of Scientific and Technical Information of China (English)

    王卓珏

    2007-01-01

    This paper mainly explains the symbolic significance of colors in the novel The Color Purple by using theory of Alice Walker's Womaism. Black,in The Color Purple stands for humbleness,blue for a life of impulse,red for liberty and hope ,purple for women's consummate happiness. And the choice of "purple" as its title ,conceives a purple centered symbolic color system,which reveals the black women's expectation for living an ideal happy life. Walker gives an expression of black women's political condition ,state of life under the racial and sexual oppression. Her intentions are to arouse women's consciousness of self and to call on them to be self-respected ,self-supported and eventually be self-liberated.

  16. Resonance Raman Spectroscopy of Purple Membrane from Halobacterium Halobium.

    Science.gov (United States)

    Argade, Pramod Vasant

    Purple membrane from the halophilic bacteria, Halobacterium halobium, contains the protein, bacteriorhodopsin, which functions as a light transducing proton pump. Understanding the molecular mechanism underlying the functioning of bacteriorhodopsin is a key problem in membrane biophysics. After absorbing a photon, this protein cycles through a series of characteristic intermeidate states and pumps H('+) ions across the membrane. In this way, the energy of the absorbed photon is stored in the electrochemical potential gradient formed across the membrane. This energy is subsequently available for metabolism by the bacterium. Bacteriorhodopsin consists of a retinal chromophore (which is responsible for the purple color) bound to the protein, bacterioopsin, whose sequence is known and consists of 248 amino acid residues. There is evidence that conformational changes in the chromophore may contribute to the proton pumping action. Resonance Raman light scattering provides a selective tool to monitor the conformational changes in the chromophore during the proton pumping cycle. This dissertation consists of applying resonance Raman light scattering in conjunction with a variety of newly developed experimental techniques to gain information about the mode of action of bacteriorhodopsin. By selective isotopic labelling of (epsilon)-amino nitrogen of the lysine residues of the protein, the site of attachment of the chromophore with the protein was verified by in situ measurements. Also, a model proposing a secondary interaction of the chromophore with a lysine residue other than the binding site of the chromophore was tested using this method. Furthermore, by selective isotopic labelling of only a part of the protein the location of the lysine on the protein to which the chromophore is bound, was found by in situ measurements to be the fragment consisting of amino acid residues 72 through 248 of the protein. This is inconsistent with the previously reported binding site at

  17. Theoretical studies on the influence of molecular interactions on the mechanism of electron transfer in photosynthetic reaction center of Rps. viridis

    Institute of Scientific and Technical Information of China (English)

    徐红; 张汝波; 屈正旺; 张兴康; 张启元

    2002-01-01

    Based on the QM/MM optimized X-ray crystal structure of the photosynthetic reaction center (PRC) of purple bacteria Rhodopseudomonas (Rps.) viridis, quantum chemistry density functional method (DFT, B3LYP/6-31G) has been performed to study the interactions between the pigment molecules and either the surrounded amino acid residues or water molecules that are either axially coordinated or hydrogen bonded with the pigment molecules, leading to an explanation of the mechanism of the primary electron-transfer (ET) reactions in the PRC. Results show that the axial coordination of amino acid residues greatly raises the ELUMO of pigment molecules and it is important for the possibility of ET to take place. Different hydrogen bonds between amino acid residues, water molecules and pigment molecules decrease the ELUMO of the pigment molecules to different extents. It is crucial for the ET taking place from excited P along L branch and sustains that the ET is a one-step reaction without through accessory bacteriochlorophyll (ABChl b). It is insufficient to treat the whole protein surrounding as a homogeneous dielectric medium.

  18. 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

  19. The Photosynthetic Cycle

    Science.gov (United States)

    Calvin, Melvin

    1955-03-21

    A cyclic sequence of transformations, including the carboxylation of RuDP (ribulose diphosphate) and its re-formation, has been deduced as the route for the creation of reduced carbon compounds in photosynthetic organisms. With the demonstration of RuDP as substrate for the carboxylation in a cell-free system, each of the reactions has now been carried out independently in vitro. Further purification of this last enzyme system has confirmed the deduction that the carboxylation of RuDP leads directly to the two molecules of PGA (phosphoglyceric acid) involving an internal dismutation and suggesting the name "carboxydismutase" for the enzyme. As a consequence of this knowledge of each of the steps in the photosynthetic CO{sub 2} reduction cycle, it is possible to define the reagent requirements to maintain it. The net requirement for the reduction of one molecule of CO{sub 2} is four equivalents of [H]and three molecules of ATP (adenine triphosphate). These must ultimately be supplied by the photochemical reaction. Some possible ways in which this may be accomplished are discussed.

  20. 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.

  1. CsmA Protein is Associated with BChl a in the Baseplate Subantenna of Chlorosomes of the Photosynthetic Green Filamentous Bacterium Oscillochloris trichoides belonging to the Family Oscillochloridaceae

    OpenAIRE

    Anastasiya Zobova; Alexandra Taisova; Eugeny Lukashev; Nataliya Fedorova; Ludmila Baratova; Zoya Fetisova

    2011-01-01

    The baseplate subantenna in chlorosomes of green anoxygenic photosynthetic bacteria, belonging to the families Chloroflexaceae and Chlorobiaceae, is known to represent a complex of bacteriochlorophyll (BChl) a with the ~6 kDa CsmA proteins. Earlier, we showed the existence of a similar BChl a subantenna in chlorosomes of the photosynthetic green bacterium Oscillochloris trichoides, member of Oscillochloridaceae, the third family of green photosynthetic bacteria. However, this BChl a subantenn...

  2. Rhodoferax antarcticus sp. nov., a moderately psychrophilic purple nonsulfur bacterium isolated from an Antarctic microbial mat

    Science.gov (United States)

    Madigan, M. T.; Jung, D. O.; Woese, C. R.; Achenbach, L. A.

    2000-01-01

    A new species of purple nonsulfur bacteria isolated from an Antarctic microbial mat is described. The organism, designated strain ANT.BR, was mildly psychrophilic, growing optimally at 15-18 degrees C with a growth temperature range of 0-25 degrees C. Cells of strain ANT.BR were highly motile curved rods and spirals, contained bacteriochlorophyll a, and showed a multicomponent in vivo absorption spectrum. A specific phylogenetic relationship was observed between strain ANT.BR and the purple bacterium Rhodoferax fermentans FR2T, and the two organisms shared several physiological and other phenotypic properties, with the notable exception of growth temperature optimum. Tests of genomic DNA hybridization, however, showed Rfx. fermentans FR2T and strain ANT.BR to be genetically distinct bacteria. Because of its unique set of properties, especially its requirement for low growth temperatures, we propose to recognize strain ANT.BR as a new species of the genus Rhodoferax, Rhodoferax antarcticus, named for its known habitat, the Antarctic.

  3. Influence of environmental factors on growth and pigment synthesis by purple thiobacteria

    Directory of Open Access Journals (Sweden)

    Y. О. Pavlova

    2007-12-01

    Full Text Available The influence of different environmental factors on growth and pigment biosynthesis by particular strains of purple thiobacteria was investigated. These strains belong to the genus Chromatium, Thiocystis, Thiocapsa and Lamprocystis and were isolated from Yavoriv sulphur mine. Calcium, magnesium, manganese, iron and sodium chloride should be included in the medium for optimal growth of these bacteria. Addition of these elements entails increasing the biomass production and synthesis of carotenoids and bacteriochlorophyll a. Initial concentration of inoculum and electron donor has essential influence on growth of purple thiobacteria. Early in the development of culture, sulphide was oxidized, and then the growth impairment and destruction of cells under exposure of light were observed. For the optimization of bacteria growth the electron donor (sulphide must be added many times during the cultivation process in the concentration, which is not exceed an inhibition dose. The additional bringing of the electron donor in the medium promotes the raise of cells’ biomass. The acetate introduction in the medium has positive influence on the pigments’ biosynthesis. The essential factor of growth and pigments’ biosynthesis is the light intensity. Peak gain of the culture growth was observed under 400 lx. The amplification of light exposure is accompanied by the decrease of growth and content of pigments in cells. Oxygen inhibits the synthesis of pigments in all strains

  4. Atomically resolved images of lithium purple bronze

    Energy Technology Data Exchange (ETDEWEB)

    Klinke, Melanie; Bienert, Robert; Waelsch, Michael; Podlich, Tatjana; Matzdorf, Rene [Experimentalphysik II, Universitaet Kassel (Germany); Jin, Rongying [Department of Physics and Astronomy, Lousiana State University (United States)

    2012-07-01

    The lithium molybdenum purple bronze Li{sub 0.9}Mo{sub 6}O{sub 17} is a quasi 1D metal at room temperature showing Luttinger liquid physics. The highly anisotropic conductivity runs along the crystallographic b axis where Mo-O chains, formed by the shared edges of the MoO{sub 6} octahedra, provide the electrical transport. Li{sub 0.9}Mo{sub 6}O{sub 17} samples were investigated with low-temperature scanning tunneling microscopy and spectroscopy. By cleaving the samples at low temperatures (60 K) we obtained atomically resolved images of the surface. In these images the Mo-O chains are visible, which are covered by layers of MoO{sub 6} octahedra and MoO{sub 4} tetrahedra.

  5. Incoming editorial: bigger, purple, pragmatic, and parsimony.

    Science.gov (United States)

    Hilsenroth, Mark J

    2011-03-01

    It is with great excitement and enthusiasm that I write to you regarding several updates, new initiatives and changes with our journal. As you may have already noticed, this includes the change to a larger format, and a return to the color purple that helped define this journal from the early 1980s through the turn of the century, as well as to the original title "Psychotherapy." The change in format will allow us to benefit from the standard American Psychological Association (APA) journal design and layout, leading to more efficient processing and arrangement within their electronic journal system. I have found this first year as the Incoming Editor of Psychotherapy to be as challenging, rewarding, and intellectually stimulating as I imagined it would be, and I remain quite excited and enthusiastic about the work ahead. (PsycINFO Database Record (c) 2011 APA, all rights reserved).

  6. Primary photosynthetic processes: from supercomplex to leaf

    NARCIS (Netherlands)

    Broess, K.

    2009-01-01

    This thesis describes fluorescence spectroscopy experiments on photosynthetic complexes that cover the primary photosynthetic processes, from the absorption of light by photosynthetic pigments to a charge separation (CS) in the reaction center (RC). Fluorescence spectroscopy is a useful tool in

  7. Purple Phototrophic Bacterium Enhances Stevioside Yield by Stevia rebaudiana Bertoni via Foliar Spray and Rhizosphere Irrigation

    Science.gov (United States)

    Wu, Jing; Wang, Yiming; Lin, Xiangui

    2013-01-01

    This study was conducted to compare the effects of foliar spray and rhizosphere irrigation with purple phototrophic bacteria (PPB) on growth and stevioside (ST) yield of Stevia. rebaudiana. The S. rebaudiana plants were treated by foliar spray, rhizosphere irrigation, and spray plus irrigation with PPB for 10 days, respectively. All treatments enhanced growth of S. rebaudiana, and the foliar method was more efficient than irrigation. Spraying combined with irrigation increased the ST yield plant -1 by 69.2% as compared to the control. The soil dehydrogenase activity, S. rebaudiana shoot biomass, chlorophyll content in new leaves, and soluble sugar in old leaves were affected significantly by S+I treatment, too. The PPB probably works in the rhizosphere by activating the metabolic activity of soil bacteria, and on leaves by excreting phytohormones or enhancing the activity of phyllosphere microorganisms. PMID:23825677

  8. Purple phototrophic bacterium enhances stevioside yield by Stevia rebaudiana Bertoni via foliar spray and rhizosphere irrigation.

    Directory of Open Access Journals (Sweden)

    Jing Wu

    Full Text Available This study was conducted to compare the effects of foliar spray and rhizosphere irrigation with purple phototrophic bacteria (PPB on growth and stevioside (ST yield of Stevia. rebaudiana. The S. rebaudiana plants were treated by foliar spray, rhizosphere irrigation, and spray plus irrigation with PPB for 10 days, respectively. All treatments enhanced growth of S. rebaudiana, and the foliar method was more efficient than irrigation. Spraying combined with irrigation increased the ST yield plant (-1 by 69.2% as compared to the control. The soil dehydrogenase activity, S. rebaudiana shoot biomass, chlorophyll content in new leaves, and soluble sugar in old leaves were affected significantly by S+I treatment, too. The PPB probably works in the rhizosphere by activating the metabolic activity of soil bacteria, and on leaves by excreting phytohormones or enhancing the activity of phyllosphere microorganisms.

  9. Multiscale photosynthetic exciton transfer

    CERN Document Server

    Ringsmuth, A K; Stace, T M; 10.1038/nphys2332

    2012-01-01

    Photosynthetic light harvesting provides a natural blueprint for bioengineered and biomimetic solar energy and light detection technologies. Recent evidence suggests some individual light harvesting protein complexes (LHCs) and LHC subunits efficiently transfer excitons towards chemical reaction centers (RCs) via an interplay between excitonic quantum coherence, resonant protein vibrations, and thermal decoherence. The role of coherence in vivo is unclear however, where excitons are transferred through multi-LHC/RC aggregates over distances typically large compared with intra-LHC scales. Here we assess the possibility of long-range coherent transfer in a simple chromophore network with disordered site and transfer coupling energies. Through renormalization we find that, surprisingly, decoherence is diminished at larger scales, and long-range coherence is facilitated by chromophoric clustering. Conversely, static disorder in the site energies grows with length scale, forcing localization. Our results suggest s...

  10. New acylated anthocyanins from purple yam and their antioxidant activity.

    Science.gov (United States)

    Moriya, Chiemi; Hosoya, Takahiro; Agawa, Sayuri; Sugiyama, Yasumasa; Kozone, Ikuko; Shin-Ya, Kazuo; Terahara, Norihiko; Kumazawa, Shigenori

    2015-01-01

    Purple yam (Dioscorea alata L.), which is widely distributed in tropical and subtropical regions, is characterized by its color and viscosity. Previous studies have shown that purple yams contain a variety of acylated anthocyanins that exhibit higher levels of antioxidant activity than the corresponding nonacylated compounds. In this study, the pigments found in purple yams from the Philippines (D. alata) were isolated and evaluated in terms of antioxidant activity. Four new acylated anthocyanins, alanins (1-4) were isolated from the MeOH extracts of purple yam, which were subsequently determined to be cyanidin (1, 2, and 4) and peonidin (3) type compounds, along with four known anthocyanins (5-8). The structures of 1-4 were determined by spectroscopic methods, including NMR and MS analyses. The antioxidant activities of anthocyanins 1-8 were investigated using oxygen radical absorbing capacity and ferric reducing antioxidant power assays.

  11. Overall energy conversion efficiency of a photosynthetic vesicle.

    Science.gov (United States)

    Sener, Melih; Strumpfer, Johan; Singharoy, Abhishek; Hunter, C Neil; Schulten, Klaus

    2016-08-26

    The chromatophore of purple bacteria is an intracellular spherical vesicle that exists in numerous copies in the cell and that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions. Building on an atomic-level structural model of a low-light-adapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle. The steady-state ATP production rate as a function of incident light intensity is determined after identifying quinol turnover at the cytochrome bc1 complex (cytb⁢c1) as rate limiting and assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state. For an illumination condition equivalent to 1% of full sunlight, the vesicle exhibits an ATP production rate of 82 ATP molecules/s. The energy conversion efficiency of ATP synthesis at illuminations corresponding to 1%-5% of full sunlight is calculated to be 0.12-0.04, respectively. The vesicle stoichiometry, evolutionarily adapted to the low light intensities in the habitat of purple bacteria, is suboptimal for steady-state ATP turnover for the benefit of protection against over-illumination.

  12. Overall energy conversion efficiency of a photosynthetic vesicle

    Science.gov (United States)

    Sener, Melih; Strumpfer, Johan; Singharoy, Abhishek; Hunter, C Neil; Schulten, Klaus

    2016-01-01

    The chromatophore of purple bacteria is an intracellular spherical vesicle that exists in numerous copies in the cell and that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions. Building on an atomic-level structural model of a low-light-adapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle. The steady-state ATP production rate as a function of incident light intensity is determined after identifying quinol turnover at the cytochrome bc1 complex (cytb⁢c1) as rate limiting and assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state. For an illumination condition equivalent to 1% of full sunlight, the vesicle exhibits an ATP production rate of 82 ATP molecules/s. The energy conversion efficiency of ATP synthesis at illuminations corresponding to 1%–5% of full sunlight is calculated to be 0.12–0.04, respectively. The vesicle stoichiometry, evolutionarily adapted to the low light intensities in the habitat of purple bacteria, is suboptimal for steady-state ATP turnover for the benefit of protection against over-illumination. DOI: http://dx.doi.org/10.7554/eLife.09541.001 PMID:27564854

  13. Affinity and activity of non-native quinones at the QB site of bacterial photosynthetic reaction centers

    Science.gov (United States)

    Zhang, Xinyu; Gunner, M. R.

    2014-01-01

    Purple, photosynthetic reaction centers (RCs) from Rb. sphaeroides bacteria use UQ10 as primary (QA) and secondary (QB) electron acceptors. Many quinones reconstitute QA function, while few will act as QB. Nine quinones were tested for their ability to bind and reconstitute QA and QB function. Only ubiquinone (UQ) reconstitutes both QA and QB function in the same protein. The affinities of the non-native quinones for the QB site were determined by a competitive inhibition assay. The affinities of benzoquinones (BQ), napthoquinone (NQ) and 2-methyl-NQ for the QB site are 7±3 times weaker than for the QA site. However, di-ortho substituted NQs and anthraquinone bind tightly to the QA site (Kd ≤200 nM) and ≥1000 times more weakly to the QB site, perhaps setting a limit on the size of the site. With a low potential electron donor (2-methyl, 3-dimethylamino-1,4-Napthoquinone (Me-diMeAm-NQ)) at QA, QB reduction is 260 meV more favorable than with UQ as QA. Electron transfer from Me-diMeAm-NQ at the QA site to NQ at the QB site can be detected. In the QB site the NQ semiquinone is estimated to be ≈ 60–100 meV higher in energy than the UQ semiquinone, while in the QA site the semiquinone energy level is similar or lower with NQ than with UQ. Thus, the NQ semiquinone is more stable in the QA than QB site. In contrast, the native UQ semiquinone is ≈ 60 meV lower in energy in the QB than the QA site, stabilizing forward electron transfer from QA to QB. PMID:23715773

  14. Effects of Bio-nematicides (Photosynthetic Bacteria and Bacillus spp.) on Controlling Cucumber Root-knot Nematode%光合细菌与芽孢杆菌生防菌剂防治黄瓜根结线虫病研究

    Institute of Scientific and Technical Information of China (English)

    成飞雪; 王忠勇; 刘勇

    2012-01-01

      利用筛选获得的对植物线虫具有毒杀活性的光合细菌菌株和芽孢杆菌菌株培养液及其混配制剂进行防治黄瓜根结线虫病田间药效试验。试验结果表明,3种菌剂对黄瓜根结线虫病都有一定的防治效果,能显著降低黄瓜根围根结线虫J2虫口密度,减少根结的形成,尤其是两菌剂复配后作用效果显著优于两单剂,说明两生防菌剂具有协同效应。同时研究结果显示,3种生防菌剂还能促进植物生长,显著提高作物产量。%  In this paper, the fermentation broth of photosynthetic bacteria and Bacillus spp. and their mixture were used for the control of cucumber root-knot nematode (Meloidogyne incognita) in field. The results showed that, the three fermen-tation broth could decrease the number of second stage juvennil (J2) of root-knot nematodes and reduce the galls forma-tion. The results showed that these two bio-nematicides were effective especially the they were mixed, which indicated that the two biocontrol bacteria had synergistic effects. The results also showed that the three treatments could promote plant growth and increase the yield.

  15. Cloning and characterization of nif structural and regulatory genes in the purple sulfur bacterium, Halorhodospira halophila.

    Science.gov (United States)

    Tsuihiji, Hisayoshi; Yamazaki, Yoichi; Kamikubo, Hironari; Imamoto, Yasushi; Kataoka, Mikio

    2006-03-01

    Halorhodospira halophila is a halophilic photosynthetic bacterium classified as a purple sulfur bacterium. We found that H. halophila generates hydrogen gas during photoautotrophic growth as a byproduct of a nitrogenase reaction. In order to consider the applied possibilities of this photobiological hydrogen generation, we cloned and characterized the structural and regulatory genes encoding the nitrogenase, nifH, nifD and nifA, from H. halophila. This is the first description of the nif genes for a purple sulfur bacterium. The amino-acid sequences of NifH and NifD indicated that these proteins are an Fe protein and a part of a MoFe protein, respectively. The important residues are conserved completely. The sequence upstream from the nifH region and sequence similarities of nifH and nifD with those of the other organisms suggest that the regulatory system might be a NifL-NifA system; however, H. halophila lacks nifL. The amino-acid sequence of H. halophila NifA is closer to that of the NifA of the NifL-NifA system than to that of NifA without NifL. H. halophila NifA does not conserve either the residue that interacts with NifL or the important residues involved in NifL-independent regulation. These results suggest the existence of yet another regulatory system, and that the development of functional systems and their molecular counterparts are not necessarily correlated throughout evolution. All of these Nif proteins of H. halophila possess an excess of acidic residues, which acts as a salt-resistant mechanism.

  16. MARKS OF ETHNICITY IN PURPLE HIBISCUS TRANSLATION

    Directory of Open Access Journals (Sweden)

    Fernanda de Oliveira Müller

    2016-10-01

    Full Text Available This study gives an analysis of the English – Brazilian Portuguese translation of Chimamanda Ngozi Adichie’s novel, Purple Hibiscus, made by Julia Romeu. It is an attempt to analyze how traces of ethnic identities marked in the source text are reproduced in the Brazilian version Hibisco Roxo, published in 2011. Initially, is a brief biography of the writer is presented together with her history towards the construction of a new paradigm for the literature about Africa and Nigeria. Adichie challenges Western stereotypes about that continent, which tend to report poverty, war and disease scenarios. Secondly, a summary of the story was made and the main characters were described. Thirdly, a collection of recorded words and phrases in the Igbo language was compiled from the original text and an analysis of the translation of those terms into Brazilian Portuguese was performed. Afterwards, the concept of ethnicity described by the sociologist Anthony Giddens was presented. Based on that concept, it was concluded that the terms previously selected could be considered as marks of ethnicity, reflecting the presence of the Igbo ethnic group in the British colonial culture. Finally, taking Antoine Berman’s proposition for an ethical translation, which embraces the foreign and rejects ethnocentrism, the conclusion to be drawn is that the translator’s option to keep Igbo terms in her work respected the author’s manifest intention of, through her work, showing the readers from other countries a bit of Nigeria’s culture and history.

  17. Toxic, antimicrobial and hemagglutinating activities of the purple fluid of the sea hare Aplysia dactylomela Rang, 1828

    Directory of Open Access Journals (Sweden)

    Melo V.M.M.

    1998-01-01

    Full Text Available The antimicrobial, hemagglutinating and toxic activities of the purple fluid of the sea hare Aplysia dactylomela are described. Intact or dialyzed purple fluid inhibited the growth of species of Gram-positive and Gram-negative bacteria and the action was not bactericidal but bacteriostatic. The active factor or factors were heat labile and sensitive to extreme pH values. The fluid preferentially agglutinated rabbit erythrocytes and, to a lesser extent, human blood cells, and this activity was inhibited by the glycoprotein fetuin, a fact suggesting the presence of a lectin. The fluid was also toxic to brine shrimp nauplii (LD50 141.25 µg protein/ml and to mice injected intraperitoneally (LD50 201.8 ± 8.6 mg protein/kg, in a dose-dependent fashion. These toxic activities were abolished when the fluid was heated. Taken together, the data suggest that the activities of the purple fluid are due primarily to substance(s of a protein nature which may be involved in the chemical defense mechanism of this sea hare.

  18. Effects of Degradation Bacteria Suspension against Flue-cured Tobacco Root Exudates on Root Structure and Photosynthetic Features of Flue-cured Tobacco Seedlings%烤烟根系分泌物降解液对烤烟幼苗根系和光合特性的影响

    Institute of Scientific and Technical Information of China (English)

    李鑫; 周冀衡; 宾俊; 王丰

    2015-01-01

    Two Lysine Bacillus and Stenotrophomonas strains were previously selected from exudates of flue-cured tobacco to be able to depredate effectively nicotine, salicylic acid and other secretions. A mixture of 5ml bacterial suspension and 45 mL secretions was added into the seedling trays to test their effects on flue-cured tobacco seedling photosynthetic characteristics, chlorophyll fluorescence characteristics, chlorophyll content and root growth. The results showed that the exudates containing degrading bacteria could improve photosynthesis during the process of seedling growth, and promote the growth of root. The degradation effect of flue-cured tobacco root exudates containing both Stenotrophomonas Bacillus and Lysine bacteria was the best, followed by the degradation solution that only contained Lysine Bacillus or Stenotrophomonas strains, and that the treating solution without degrading bacteria inhibited the growth of flue-cured tobacco seedlings. In the pot experiment, both bacteria were capable of reducing the inhibition of tobacco growth by root exudates, with the best effect observed when both bacteria were used.%从烤烟根系分泌物中筛选出能够有效降解烟碱和水杨酸等主要成分的赖氨酸芽孢杆菌和寡养单胞菌两种细菌,以5 mL菌液和45 mL分泌物混合施入育苗盘中进行幼苗培养并测定和分析其对烤烟幼苗光合特性、叶绿素荧光特性、叶绿素含量和幼苗根系生长的差异。结果表明,含有降解菌的处理液可提高幼苗生长过程中的光合作用,促进根系生长,同时含寡养单胞菌和赖氨酸芽孢杆菌的处理液对烤烟根系分泌物降解效果最佳,只含有降解水杨酸的寡养单胞菌和赖氨酸芽孢杆菌的降解液处理次之,不含降解菌的处理液对烤烟幼苗生长有抑制作用。盆栽试验中,两种菌均能够降低烤烟根系分泌物对烤烟生长的抑制作用,当两种菌混合后效果最好。

  19. Dye-sensitized solar cells based on purple corn sensitizers

    Energy Technology Data Exchange (ETDEWEB)

    Phinjaturus, Kawin [Materials Science and Nanotechnology Program, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Maiaugree, Wasan [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Suriharn, Bhalang [Department of Plant Science and Agricultural Resources, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002 (Thailand); Pimanpaeng, Samuk; Amornkitbamrung, Vittaya [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Integrated Nanotechnology Research Center (INRC), Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Swatsitang, Ekaphan, E-mail: ekaphan@kku.ac.th [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Integrated Nanotechnology Research Center (INRC), Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Nanotec-KKU Center of Excellence on Advanced Nanomaterials for Energy Production and Storage, Khon Kaen 40002 (Thailand)

    2016-09-01

    Graphical abstract: - Highlights: • Extract from husk, cob and silk of purple corn was used as a photosensitizer in DSSC. • Effect of solvents i.e. acetone, ethanol and DI water on DSSC efficiency was studied. • The highest efficiency of 1.06% was obtained in DSSC based on acetone extraction. - Abstract: Natural dye extracted from husk, cob and silk of purple corn, were used for the first time as photosensitizers in dye sensitized solar cells (DSSCs). The dye sensitized solar cells fabrication process has been optimized in terms of solvent extraction. The resulting maximal efficiency of 1.06% was obtained from purple corn husk extracted by acetone. The ultraviolet–visible (UV–vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and incident photon-to-current efficiency (IPCE) were employed to characterize the natural dye and the DSSCs.

  20. Proteomic analysis of the purple sulfur bacterium Candidatus “Thiodictyon syntrophicum” strain Cad16T isolated from Lake Cadagno

    Directory of Open Access Journals (Sweden)

    Nicola Storelli

    2014-03-01

    Full Text Available Lake Cadagno is characterised by a compact chemocline with high concentrations of purple sulfur bacteria (PSB. 2D-DIGE was used to monitor the global changes in the proteome of Candidatus “Thiodictyon syntrophicum” strain Cad16T both in the presence and absence of light. This study aimed to disclose details regarding the dark CO2 assimilation of the PSB, as this mechanism is often observed but is not yet sufficiently understood. Our results showed the presence of 17 protein spots that were more abundant in the dark, including three enzymes that could be part of the autotrophic dicarboxylate/4-hydroxybutyrate cycle, normally observed in archaea.

  1. Applications of the Phytomedicine Echinacea purpurea (Purple Coneflower in Infectious Diseases

    Directory of Open Access Journals (Sweden)

    James B. Hudson

    2012-01-01

    Full Text Available Extracts of Echinacea purpurea (EP, purple coneflower have been used traditionally in North America for the treatment of various types of infections and wounds, and they have become very popular herbal medicines globally. Recent studies have revealed that certain standardized preparations contain potent and selective antiviral and antimicrobial activities. In addition, they display multiple immune-modulatory activities, comprising stimulation of certain immune functions such as phagocytic activity of macrophages and suppression of the proinflammatory responses of epithelial cells to viruses and bacteria, which are manifested as alterations in secretion of various cytokines and chemokines. These immune modulations result from upregulation or downregulation of the relevant genes and their transcription factors. All these bioactivities can be demonstrated at noncytotoxic concentrations of extract and appear to be due to multiple components rather than the individual chemical compounds that characterize Echinacea extracts. Potential applications of the bioactive extracts may go beyond their traditional uses.

  2. Purple-bacterial light harvesting benefits more from energy funnelling than from delocalisation

    CERN Document Server

    Baghbanzadeh, Sima

    2015-01-01

    Light-harvesting complexes of purple bacteria have two properties that are thought to contribute to the efficiency of their exciton transport: an energy funnel that directs excitons towards the reaction centre as well as substantial excitonic delocalisation, which can enhance transport through supertransfer. To determine the relative importance of these two features, we compared models of the light-harvesting apparatus with thousands of counterfactual situations in which the extent of delocalisation and the energy landscape were altered. We find that the influence of delocalisation is usually minor and sometimes deleterious, especially when compared to the decisive importance of a funnel in the energy landscape. Consequently, delocalisation is most likely a side-effect of the dense chlorophyll packing that evolved to increase light absorption per reaction centre.

  3. Applications of the phytomedicine Echinacea purpurea (Purple Coneflower) in infectious diseases.

    Science.gov (United States)

    Hudson, James B

    2012-01-01

    Extracts of Echinacea purpurea (EP, purple coneflower) have been used traditionally in North America for the treatment of various types of infections and wounds, and they have become very popular herbal medicines globally. Recent studies have revealed that certain standardized preparations contain potent and selective antiviral and antimicrobial activities. In addition, they display multiple immune-modulatory activities, comprising stimulation of certain immune functions such as phagocytic activity of macrophages and suppression of the proinflammatory responses of epithelial cells to viruses and bacteria, which are manifested as alterations in secretion of various cytokines and chemokines. These immune modulations result from upregulation or downregulation of the relevant genes and their transcription factors. All these bioactivities can be demonstrated at noncytotoxic concentrations of extract and appear to be due to multiple components rather than the individual chemical compounds that characterize Echinacea extracts. Potential applications of the bioactive extracts may go beyond their traditional uses.

  4. Dye-sensitized solar cells based on purple corn sensitizers

    Science.gov (United States)

    Phinjaturus, Kawin; Maiaugree, Wasan; Suriharn, Bhalang; Pimanpaeng, Samuk; Amornkitbamrung, Vittaya; Swatsitang, Ekaphan

    2016-09-01

    Natural dye extracted from husk, cob and silk of purple corn, were used for the first time as photosensitizers in dye sensitized solar cells (DSSCs). The dye sensitized solar cells fabrication process has been optimized in terms of solvent extraction. The resulting maximal efficiency of 1.06% was obtained from purple corn husk extracted by acetone. The ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and incident photon-to-current efficiency (IPCE) were employed to characterize the natural dye and the DSSCs.

  5. Phototropic sulfur and sulfate-reducing bacteria in the chemocline of meromictic Lake Cadagno, Switzerland

    Directory of Open Access Journals (Sweden)

    Raffaele PEDUZZI

    2004-08-01

    Full Text Available Lake Cadagno, a crenogenic meromictic lake located in the catchment area of a dolomite vein rich in gypsum in the Piora Valley in the southern Alps of Switzerland, is characterized by a compact chemocline with high concentrations of sulfate, steep gradients of oxygen, sulfide and light and a turbidity maximum that correlates to large numbers of bacteria (up to 107 cells ml-1. The most abundant taxa in the chemocline are large- and small-celled purple sulfur bacteria, which account for up to 35% of all bacteria, and sulfate- reducing bacteria that represent up to 23% of all bacteria. Depending on the season, as much as 45% of all bacteria in the chemocline are associated in aggregates consisting of different populations of small-celled purple sulfur bacteria of the genus Lamprocystis (up to 35% of all bacteria and sulfate-reducing bacteria of the family Desulfobulbaceae (up to 12% of all bacteria that are almost completely represented by bacteria closely related to Desulfocapsa thiozymogenes. Their association in aggregates is restricted to small-celled purple sulfur bacteria of the genus Lamprocystis, but not obligate since non-associated cells of bacteria related to D. thiozymogenes are frequently found, especially under limited light conditions in winter and early summer. Aggregate formation and concomitant growth enhancement of isolates of both partners of this association suggests synergistic interactions that might resemble a sulfide-based source-sink relationship between the sulfate-reducing bacterium that is able to sustain growth by a disproportionation of inorganic sulfur compounds (sulfur, thiosulfate, sulfite, with the purple sulfur bacteria acting as a biotic scavenger. The availability of these isolates opens up the door for future studies considering other facets of potential interactions in aggregates since both types of organisms are metabolically highly versatile and interactions may not be limited to sulfur compounds only.

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

    African Journals Online (AJOL)

    AJL

    2012-02-21

    Feb 21, 2012 ... Full Length Research Paper ... photosynthetic measurement system, high performance liquid chromatography and SPSS13.0 software. ... net photosynthetic rate and lycorine and galantamine contents. .... Pigment analysis.

  7. Calcium binding to the purple membrane : A molecular dynamics study

    NARCIS (Netherlands)

    Wassenaar, Tsjerk A.; Daura, Xavier; Padros, Esteve; Mark, Alan E.

    2009-01-01

    The purple membrane (PM) is a specialized membrane patch found in halophilic archaea, containing the photoreceptor bacteriorhodopsin (bR). It is long known that calcium ions bind to the PM, but their position and role remain elusive to date. Molecular dynamics simulations in conjunction with a highl

  8. Defined fungal starter granules for purple glutinous rice wine

    NARCIS (Netherlands)

    Ngo Thi Phuong Dung, N.T.P.

    2004-01-01

    The Mekong Delta region ofSouth Vietnamis particularly known as a production area of purple glutinous rice wine ( RuouNepThan ). The latter differs from regular

  9. Using polyvinyl chloride dyed with bromocresol purple in radiation dosimetry.

    Science.gov (United States)

    Kattan, Munzer; al Kassiri, Haroun; Daher, Yarob

    2011-02-01

    Polyvinyl chloride (PVC) dyed with bromocresol purple was investigated as a high-dose radiation dosimeter. The absorbance at 417 nm depends linearly on the dose below 50 kGy. The response depends neither on dose rate nor on the irradiation temperature. The effects of post-irradiation storage in the dark and in indirect sunlight are also discussed.

  10. Halosulfuron reduced purple nutsedge (Cyperus rotundus) tuber production and viability

    Science.gov (United States)

    Weeds persist and cause economic losses in agricultural systems because they exploit an underutilized portion of that system. Reducing the impact of weeds on agroecosystems begins with minimizing the number of propagules (e.g, seeds and tubers) that are produced and returned to the soil. Purple nu...

  11. Alice Walker's Womanism Colored in The Color Purple

    Institute of Scientific and Technical Information of China (English)

    蒋慧慧

    2009-01-01

    In her famous novel The Color Purple,Alice Walker's womanism is colored by four kinds of conseiousness-female consciousness,racial consciousness,root-seeking consciousness,and universal consciousness.It is owing to the womanism that the heroine celie grown from an abused woman to an independent selfhood.

  12. Purple Bacterial Light-harvesting Complexes: From Dreams to Structures.

    Science.gov (United States)

    Cogdell, Richard J; Hashimoto, Hideki; Gardiner, Alastair T

    2004-01-01

    This paper describes the main stages involved in the research efforts designed to try and understand the structure and function of purple bacterial antenna complexes. Wherever possible the work has been illustrated by pictures of the major people who carried it out.

  13. Defined fungal starter granules for purple glutinous rice wine

    NARCIS (Netherlands)

    Ngo Thi Phuong Dung, N.T.P.

    2004-01-01

    The Mekong Delta region ofSouth Vietnamis particularly known as a production area of purple glutinous rice wine ( RuouNepThan ). The latter differs from regular ri

  14. Heterosis of maize photosynthetic performance

    Institute of Scientific and Technical Information of China (English)

    LI Xia; DING Zaisong; LI Lianlu; WANG Meiyun; ZHAO Ming

    2007-01-01

    Four maize inbred lines with different photosyn-thetic rates and their two hybrids were used as test materials,and the diurnal variations of their photosynthesis parameters in the silking stage were measured to study the heterosis of photosynthetic performance.Results showed that net photo-synthetic rate (In),transpiration rate (Tr) and stomatal conductance (Gs) all presented an obvious single-peaked curve in a day,with the peak values occurring at 10:00-12:00,12:00,10:00-12:00 a.m.,respectively,while water use efficiency (WUE) had a"V"type variant trend,with the lowest value appearing at 12:00.The diurnal variation of Pn and Tr was correlated markedly with Gs,suggesting that Gs played an important role in regulating the diurnal variation of Pn and Tr,and Pn,Tr and Gs had a higher heterosis in the afternoon than in the morning,while the WUE was in reverse,indicating that maize hybrid had higher resistance to the high temperature and dehydration in the afternoon,which provided a new path to select varieties with a high net photosynthetic rate.

  15. Primary photosynthetic processes: from supercomplex to leaf

    NARCIS (Netherlands)

    Broess, K.

    2009-01-01

    This thesis describes fluorescence spectroscopy experiments on photosynthetic complexes that cover the primary photosynthetic processes, from the absorption of light by photosynthetic pigments to a charge separation (CS) in the reaction center (RC). Fluorescence spectroscopy is a useful tool in phot

  16. Tracking photosynthetic sulfide oxidation in a meromictic lake using sulfate δ34S and δ18O

    Science.gov (United States)

    Gilhooly, W. P.; Reinhard, C.; Lyons, T. W.; Glass, J. B.

    2012-12-01

    Phototrophic sulfur bacteria oxidize sulfide and fix carbon dioxide in the presence of sunlight without producing oxygen. Environmental conditions in the Paleo- and Mesoproterozoic, when atmospheric oxygen concentrations were at low levels and portions of the oceans were anoxic and sulfidic (euxinic), were conducive to widespread carbon fixation by anoxygenic photosynthesis. This pathway may have helped sustain euxinic conditions in the Proterozoic water column. With limited organic biomarker and geochemical evidence for widespread production of anoxygenic phototrophs, however, additional proxies are needed to fingerprint paleoecological and biogeochemical signals associated with photic zone euxinia. Paired δ34S and δ18O from ancient sulfates (gypsum, barite, or CAS) may offer an added constraint on the history and ecological dominance of photosynthetic S-oxidation. Sulfate-oxygen can fractionate during sulfate reduction, but the extent of isotopic enrichment is controlled either by kinetic isotope effects imparted during intracellular enzymatic steps or equilibrium oxygen exchange with ambient water. An improved understanding of these processes can be gained from modern natural environments. Mahoney Lake is a density-stratified lake located within the White Lake Basin of British Columbia. The euxinic water column supports a dense plate of purple sulfur bacteria (Amoebobacter purpureus) that thrives where free sulfide intercepts the photic zone at ~7 m water depth. We analyzed the isotopic composition of sulfate (δ34SSO4 and δ18OSO4), sulfide (δ34SH2S), and water (δ18OH2O) to track the potentially coupled processes of dissimilatory sulfate reduction and phototrophic sulfide oxidation within this meromictic lake. Large isotopic offsets observed between sulfate and sulfide within the monimolimnion (δ34SSO4-H2S = 51‰) and within pore waters along the oxic margin (δ34SSO4-H2S >50‰) are consistent with sulfate reduction in both the sediments and the anoxic

  17. [Carbon monoxide metabolism by photosynthetic bacteria]. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    1989-12-31

    Research continued on the metabolism of carbon monoxide by Rhodospirillum rubrum. This report discusses progress on the activity, induction, inhibition, and spectroscopic analysis of the enzyme Carbon Monoxide Dehydrogenase. (CBS)

  18. The nature of the lower excited state of the special pair of bacterial photosynthetic reaction center of Rhodobacter Sphaeroides and the dynamics of primary charge separation

    Science.gov (United States)

    Ivashin, N. V.; Shchupak, E. E.

    2016-08-01

    Quantum-chemical calculations of the structure in the ground and lower singlet excited states and the vibrations (in the ground state) of special pair P of photosynthetic reaction center of purple bacteria (RCPb) Rhodobacter Sphaeroides, consisting of two bacteriochlorophyll molecules PA and PB, have been carried out. It is shown that excitation of the special pair is followed by fast relaxation dynamics, accompanied by the transformation of the initial P* state into the P A δ+ P B δ- state (δ ~ 0.5) with charge separation. This behavior is due to the presence of several nonplanar vibrations with participation of the acetyl group of macrocycle PB in the nuclear wave packet on the potential surface of the P* state; these vibrations facilitate destabilization of the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) of the macrocycle PA and formation of the P A δ+ P B δ- state. The structural transformations in the P* state are due to its linking character in the contact region of the acetyl group-containing pyrrole rings of PA and PB. The transition from the P* state to specifically the P A δ+ P B δ- state is related to the fact that the acetyl group PA is involved in the intermolecular hydrogen bond with amino acid residue HisL168; for this reason, this group and the pyrrole ring linked with it can hardly participate in structural transformations. The electronic matrix element H12 of the electron transfer from the special pair in the P A δ+ P B δ- state to a molecule of accessory bacteriochlorophyll BA greatly exceeds that for the transfer to BB. This circumstance and the fact that the P A δ+ P B δ- state is energetically more favorable than the P* state facilitate the preferred directionality of the electron transfer in RCPb Rhodobacter Sphaeroides with participation of the cofactors located in its subunit L.

  19. Innovative Approaches Using Lichen Enriched Media to Improve Isolation and Culturability of Lichen Associated Bacteria

    OpenAIRE

    Biosca, Elena G.; Flores, Raquel; Ricardo D Santander; D?ez-Gil, Jos? Luis; Barreno, Eva

    2016-01-01

    Lichens, self-supporting mutualistic associations between a fungal partner and one or more photosynthetic partners, also harbor non-photosynthetic bacteria. The diversity and contribution of these bacteria to the functioning of lichen symbiosis have recently begun to be studied, often by culture-independent techniques due to difficulties in their isolation and culture. However, culturing as yet unculturable lichenic bacteria is critical to unravel their potential functional roles in lichen sy...

  20. Thiorhodospira sibirica gen. nov., sp. nov., a new alkaliphilic purple sulfur bacterium from a Siberian soda lake.

    Science.gov (United States)

    Bryantseva, I; Gorlenko, V M; Kompantseva, E I; Imhoff, J F; Süling, J; Mityushina, L

    1999-04-01

    A new purple sulfur bacterium was isolated from microbial films on decaying plant mass in the near-shore area of the soda lake Malyi Kasytui (pH 9.5, 0.2% salinity) located in the steppe of the Chita region of south-east Siberia. Single cells were vibrioid- or spiral-shaped (3-4 microns wide and 7-20 microns long) and motile by means of a polar tuft of flagella. Internal photosynthetic membranes were of the lamellar type. Lamellae almost filled the whole cell, forming strands and coils. Photosynthetic pigments were bacteriochlorophyll a and carotenoids of the spirilloxanthin group. The new bacterium was strictly anaerobic. Under anoxic conditions, hydrogen sulfide and elemental sulfur were used as photosynthetic electron donors. During growth on sulfide, sulfur globules were formed as intermediate oxidation products. They were deposited outside the cytoplasm of the cells, in the peripheral periplasmic space and extracellularly. Thiosulfate was not used. Carbon dioxide, acetate, pyruvate, propionate, succinate, fumarate and malate were utilized as carbon sources. Optimum growth rates were obtained at pH 9.0 and optimum temperature was 30 degrees C. Good growth was observed in a mineral salts medium containing 5 g sodium bicarbonate l-1 without sodium chloride. The new bacterium tolerated up to 60 g sodium chloride l-1 and up to 80 g sodium carbonates l-1. Growth factors were not required. The DNA G + C composition was 56.0-57.4 mol%. Based on physiological, biochemical and genetic characteristics, the newly isolated bacterium is recognized as a new species of a new genus with the proposed name Thiorhodospira sibirica.

  1. 光合细菌改善Cd、Pb及呋喃丹污染土壤的微生物群落DNA序列多样性的研究%Study on DNA sequence diversity of soil microbial community contaminated by cadmium, lead and carbofuran using photosynthetic bacteria

    Institute of Scientific and Technical Information of China (English)

    白红娟; 肖根林; 仪治本; 杨斌盛

    2011-01-01

    应用DNA随机扩增多态性(RAPD)分子标记技术研究了光合细菌(PSB)对Cd、Pb及呋喃丹污染土壤的微生物群落DNA序列多样性的影响.结果表明,Cd、Pb及呋喃丹单一污染或3者复合污染土壤的微生物群落DNA序列的丰富度相对对照土样(S0)都有不同程度的增加,受Cd、Pb或呋哺丹污染,可能会引起土壤微生物群落DNA序列本身发生变化;S0与加入PSB的土样(Cd、Pb及呋喃丹单一污染土样或3者复合污染土样)微生物群落间的DNA序列的相似系数要高于S0与不加PSB的土样(Cd、Pb及呋喃丹单一污染土样或3者复合污染土样)微生物群落间的DNA序列,PSB对改善土壤微生物群落DNA序列的组成有积极的影响.%The effect of photosynthetic bacteria (PSB) on DNA sequence diversity of soil microbial communities contaminated by cadmium, lead and carbofuran was evaluated by using random amplified polymorphic DNA (RAPD) fingerprints. The results showed that DNA sequence richness of single cadmium, lead, carbofuran contaminated soil and compound polluted soil was higher than that of control soil sample (So). Cadmium, lead and carbofuran contamination could vary the DNA sequence of microbial communities in soil. The similarity coefficients of microbial community DNA sequences between So and contaminated soil (cadmium, lead, carbofuran and compound polluted soil) containing PSB was higher than that between So and contaminated soil without PSB. PSB had positive impact on improving soil microbial communities DNA sequence.

  2. 六味地黄生物制剂多糖对果蝇寿命及繁殖力的影响%Effect of Liuweidihuang decoction metabolized by photosynthetic bacteria (LW-PSB) polysaccharides on the lifespan and fertility in Drosophila melanogaster

    Institute of Scientific and Technical Information of China (English)

    陈朋; 吴思; 李天河; 丘婷; 赵越

    2012-01-01

    Objective To study the effect of Liuweidihuang decoction metabolized by photosynthetic bacteria (LW-PSB) pqjysaccharides on the lifespan and fertility in Drosophila melanogaster. Methods Drosophila melanogaster were fed with different concentrations of LW-PSB polysaccharides (0. 1%, 0. 3% and 0. 9% ) and normal medium was used as a control group. The lifespan and fertility of Drosophila melanogaster were observed. Results LW-PSB polysaccharides prolonged female Drosophila average life, maximum life, half death time and male Drosophila maximum life. Importantly, LW-PSB polysaccharides also enhanced Drosophila productivity. Conclusion The effects of LW-PSB polysaccharides in prolongation of Drosophila melanogaster aging are satisfactory.%目的 研究六味地黄生物制剂多糖对果蝇寿命及繁殖力的影响.方法 采用美国黑腹果蝇为实验材料,经口喂果蝇不同质量浓度(0.1%、0.3%、0.9%)的六味地黄生物制剂多糖提取物,以普通培养基作为空白对照,观察其对果蝇寿命和繁殖力的影响.结果 各浓度的六味地黄生物制剂多糖能够延长雌性果蝇的半数死亡时间、最高寿命、平均寿命及延长雄性果蝇的最高寿命,且能增加果蝇子一代和子二代成虫数.结论 六味地黄生物制剂多糖对果蝇具有良好的抗衰延寿作用并提高其生殖能力,提示六味地黄生物制剂多糖可能为该制剂抗衰老作用的物质基础之一.

  3. Phytochromes in photosynthetically competent plants

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, L.H.

    1990-07-01

    Plants utilize light as a source of information in photomorphogenesis and of free energy in photosynthesis, two processes that are interrelated in that the former serves to increase the efficiency with which plants can perform the latter. Only one pigment involved in photomorphogenesis has been identified unequivocally, namely phytochrome. The thrust of this proposal is to investigate this pigment and its mode(s) of action in photosynthetically competent plants. Our long term objective is to characterize phytochrome and its functions in photosynthetically competent plants from molecular, biochemical and cellular perspectives. It is anticipated that others will continue to contribute indirectly to these efforts at the physiological level. The ultimate goal will be to develop this information from a comparative perspective in order to learn whether the different phytochromes have significantly different physicochemical properties, whether they fulfill independent functions and if so what these different functions are, and how each of the different phytochromes acts at primary molecular and cellular levels.

  4. Electron paramagnetic resonance study of a photosynthetic microbial mat and comparison with Archean cherts.

    Science.gov (United States)

    Bourbin, M; Derenne, S; Gourier, D; Rouzaud, J-N; Gautret, P; Westall, F

    2012-12-01

    Organic radicals in artificially carbonized biomass dominated by oxygenic and non-oxygenic photosynthetic bacteria, Microcoleus chthonoplastes-like and Chloroflexus-like bacteria respectively, were studied by Electron Paramagnetic Resonance (EPR) spectroscopy. The two bacteria species were sampled in mats from a hypersaline lake. They underwent accelerated ageing by cumulative thermal treatments to induce progressive carbonization of the biological material, mimicking the natural maturation of carbonaceous material of Archean age. For thermal treatments at temperatures higher than 620 °C, a drastic increase in the EPR linewidth is observed in the carbonaceous matter from oxygenic photosynthetic bacteria and not anoxygenic photosynthetic bacteria. This selective EPR linewidth broadening reflects the presence of a catalytic element inducing formation of radical aggregates, without affecting the molecular structure or the microstructure of the organic matter, as shown by Raman spectroscopy and Transmission Electron Microscopy. For comparison, we carried out an EPR study of organic radicals in silicified carbonaceous rocks (cherts) from various localities, of different ages (0.42 to 3.5 Gyr) and having undergone various degrees of metamorphism, i.e. various degrees of natural carbonization. EPR linewidth dispersion for the most primitive samples was quite significant, pointing to a selective dipolar broadening similar to that observed for carbonized bacteria. This surprising result merits further evaluation in the light of its potential use as a marker of past bacterial metabolisms, in particular oxygenic photosynthesis, in Archean cherts.

  5. Synthesis of solar cells sensitized using natural photosynthetic pigments & study for the cell performance under different synthesis parameters

    Science.gov (United States)

    Roa, Simon; Radhakrishnan, Sivakumar; Manidurai, Paulraj

    2016-05-01

    In this study we used photosynthetic pigments extracted from spinach and purple cabbage for their potential application in dye sensitized solar cells (DSSC). Pigments were extracted by dissolving small amounts of each one of these plant products in methanol and distilled water. The extraction was also done at two different temperatures (70° C and 80° C respectively). This was to assess for the solvent that promotes better extraction of the pigments. A parallel study was also carried out using a mixture of both these dyes in 1:1 ratio. Good absorption, about 60% to 80% was obtained for spinach pigments diluted in methanol in the visible range between 400-480nm, and between 9% to 15% for purple cabbage pigments in the wavelength range between 480-630 nm when extracted using distilled water at 80°C. In contrast, the diluted mixture in methanol shows good absorption of 20% and 32% for wavelengths in the range 400-480nm. Solar cells sensitized using these natural dyes were studied for their photovoltaic properties by measuring current-voltage behavior. Efficiencies ranging from 0.011% to 0.0719% were observed. Mixture of spinach & purple cabbage pigments extracted using methanol was found to have the highest efficiency of 0.0719%.

  6. Isolation and Biological Characteristics of Photosynthetic Bacterium Strain PSB-1

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@Photosynthetic bacteria(PSB) with multiple functions of applying photo-energy and complex metabolism, are widely spread in lakes, rivers and seas. According to Bergey's manual of systematic bacteriology, the PSB includes at least 27 genera[1]. In recent years, some new species of PSB have been reported The study of PSB is of high value in theory and practice. Some new biochemical compounds derived from PSB are discovered with the potentiality of insecticide, fungicide, herbicide and bacteriacide[8,9].PSB can also be applied to the control of environment,and industries of energy and feed.[8,9,10

  7. An Analysis of Ecowomanism in The Color Purple

    Institute of Scientific and Technical Information of China (English)

    陈静颖

    2016-01-01

    The Color Purple is a well known work of Alice Walker, which describes black women living in the bottom of that soci?ety and a course of them keep fighting for realizing spiritual liberation and personality independence, as well as equality in politics and race. Many scholars at home and abroad prefer to study this novel from feminism, womanism, and writing technique, but few study it from ecowamnism perspcctive. This thesis intends to take The Color Purple of Alice Walker as a research object, ecowom?anism as a theoretical basis for reflecting ecowomanism in it and actual meanings. Only when women bravely realized their self-value, beauty and preciousness and knew the self-importance and being an independent person from spiritual and body, can they achieve happiness. Only we respect, close, head for nature, can harmonious coexistence with nature be realized.

  8. Antioxidative effect of purple corn extracts during storage of mayonnaise.

    Science.gov (United States)

    Li, Chun-Ying; Kim, Hee-Woong; Li, He; Lee, Deug-Chan; Rhee, Hae-Ik

    2014-01-01

    Anthocyanin is a powerful natural antioxidant. Purple corn husk is rich in anthocyanin. In this paper the antioxidative effect of anthocyanin-rich purple corn husk extract (PCHE) in mayonnaise during storage was studied. The antioxidative effect of the mayonnaise containing PCHE was evaluated by measuring peroxide values, p-anisidine values, total oxidation values, acid values, and iodine values at time intervals for 10 weeks. The antioxidative effect of the mayonnaise containing PCHE was higher than that of mayonnaise with chemical antioxidants BHT and EDTA as positive control. The mayonnaise containing 0.4 g/kg PCHE showed the strongest antioxidative performance during storage. This study suggests that PCHE could be used as natural antioxidant in high fat food and as a substitute to chemical antioxidant with its purplish colour marking its difference from ordinary mayonnaise. Such colour difference will tell consumers that their food contains natural antioxidants. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. The Modulatory Effect of Anthocyanins from Purple Sweet Potato on Human Intestinal Microbiota in Vitro.

    Science.gov (United States)

    Zhang, Xin; Yang, Yang; Wu, Zufang; Weng, Peifang

    2016-03-30

    In order to investigate the modulatory effect of purple sweet potato anthocyanins (PSPAs) on human intestinal microbiota, PSPAs were prepared by column chromatography and their influence on intestinal microbiota was analyzed by monitoring the bacterial populations and analyzing short-chain fatty acid (SCFA) concentrations at different time points. The numbers (log10 cell/mL) of Bifidobacterium and Lactobacillus/Enterococcus spp., Bacteroides-Prevotella, Clostridium histolyticum, and total bacteria after 24 h of culture in anaerobic fermentation broth containing PSPAs were 8.44 ± 0.02, 8.30 ± 0.01, 7.80 ± 0.03, 7.60 ± 0.03, and 9.00 ± 0.02, respectively, compared with 8.21 ± 0.03, 8.12 ± 0.02, 7.95 ± 0.02, 7.77 ± 0.02, and 9.01 ± 0.03, respectively, in the controls. The results showed that PSPAs induced the proliferation of Bifidobacterium and Lactobacillus/Enterococcus spp., inhibited the growth of Bacteroides-Prevotella and Clostridium histolyticum, and did not affect the total bacteria number. Total SCFA concentrations in the cultures with PSPAs were significantly higher than in the controls (P microbiota, contributing to improvements in human health.

  10. The Psychological Deformity of Black Males in The Color Purple

    Institute of Scientific and Technical Information of China (English)

    李佳蔚

    2012-01-01

      The Color Purple,adapted from Alice Walker’s magnum opus - a long epistolary novel,is a famous movie about the miserable experience of black females and their unremitting resistance against every kind of oppression. In addition,this movie has also exposed the psychological deformity of black male. This paper focuses on the characters of black male, sufficiently probes and analyses the causes of black male’s psychological deformity.

  11. Mammalian-like Purple Acid Phosphatases in Plants

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Introduction Purple acid phosphatases (PAPs) comprise of a family of binuclear metal-containing hydrolases, some members of which have been isolated and characterized from animal, plant and fungal sources[1]. PAPs not only catalyze the hydrolyses of a wide range of phosphate esters and anhydrides under acidic reaction conditions,but also catalyze the generation of hydroxyl radicals in a Fenton-like reaction, by virtue of the presence of a redox-active binuclear metal center.

  12. Photocurrent of a single photosynthetic protein

    Science.gov (United States)

    Gerster, Daniel; Reichert, Joachim; Bi, Hai; Barth, Johannes V.; Kaniber, Simone M.; Holleitner, Alexander W.; Visoly-Fisher, Iris; Sergani, Shlomi; Carmeli, Itai

    2012-10-01

    Photosynthesis is used by plants, algae and bacteria to convert solar energy into stable chemical energy. The initial stages of this process--where light is absorbed and energy and electrons are transferred--are mediated by reaction centres composed of chlorophyll and carotenoid complexes. It has been previously shown that single small molecules can be used as functional components in electric and optoelectronic circuits, but it has proved difficult to control and probe individual molecules for photovoltaic and photoelectrochemical applications. Here, we show that the photocurrent generated by a single photosynthetic protein--photosystem I--can be measured using a scanning near-field optical microscope set-up. One side of the protein is anchored to a gold surface that acts as an electrode, and the other is contacted by a gold-covered glass tip. The tip functions as both counter electrode and light source. A photocurrent of ~10 pA is recorded from the covalently bound single-protein junctions, which is in agreement with the internal electron transfer times of photosystem I.

  13. Extraction and Purification of Pigment from Purple Sweet Potato Wine Vinasse

    Directory of Open Access Journals (Sweden)

    Zhongsheng Zhao

    2015-02-01

    Full Text Available Purple sweet potato pigment is a natural food pigment with bright color and multiplies biological functions such as antioxidant activity etc. There is a large amount of unused pigment in the vinasse of purple sweet potato wine. Therefore, in this study, the extraction processes of purple sweet potato pigment from purple sweet potato wine vinasse, as well as its purification conditions were investigated. As the results, 0.9% citric acid-95% ethanol (2/3, v/v was a suitable extraction solvent to obtain the higher yield of purple sweet potato pigment from vinasse. AB-8 column chromatography showed that the loading ratio of 1/10 (w/v of resin and pigment with the solvent of 40% ethanol at the flow rate of 2 mL/min were the optimal conditions for the purification of purple sweet potato pigment.

  14. 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.

  15. Fullerene-Benzene purple and yellow clusters: Theoretical and experimental studies

    Science.gov (United States)

    Lundgren, Megan P.; Khan, Sakiba; Baytak, Aysegul K.; Khan, Arshad

    2016-11-01

    Fullerene (FR, C60) gives a purple colored solution almost instantly when benzene is added to it. Interestingly, this purple solution turns yellow in about 7 weeks and remains yellow afterwards. The concentration of the purple complex increases with temperature indicating its formation kinetically favored, which transforms into a more stable yellow complex very slowly with time. The geometry optimization by density functional theory (DFT) followed by spectra (TD-DFT method) calculations suggest that the purple and yellow complexes are due to clusters of six benzene molecules arranged vertically and horizontally respectively around the FR molecule.

  16. Effect of the Purple carbon black on the properties of NR/BR blend

    Science.gov (United States)

    Yanfang, Zhao; Dan, Liu; Shengbo, Lin; Binjian; Yinmei, Zhao; Shuangquan, Liao

    2014-08-01

    Purple black is light colored mineral filler mining in recent years in Hainan. The effect of the dosage of the purple carbon black and purple carbon black modificated by Si69 on the vulcanization characteristics, mechanical properties, thermal stability, the damping performance of NR/BR blend rubber were studied, and the blending adhesive tensile sections were analyzed by SEM. Research showed that, with the increasing dosage of the purple carbon black, vulcanization characteristics of NR/BR blend had a little change. Adding the purple carbon black into blending had a reinforcing effect. when the dosage of the purple carbon black was 20, the mechanical properties of blending adhesive was good; Coupling agent Si69 had a modification effect on the purple carbon black. With increasing dosage of Si69, performance of the rubber was improved initially and then decreased; when the mass fraction of Si69 was 8% of the dosage of the purple carbon black, rubber performance was optimal. Purple carbon black had no obvious effect on thermal stability of the rubber, but it improved the damping rubber temperature and damping factor.

  17. Development of a Photosynthetic Microbial Electrochemical Cell (PMEC Reactor Coupled with Dark Fermentation of Organic Wastes: Medium Term Perspectives

    Directory of Open Access Journals (Sweden)

    Samir Bensaid

    2015-01-01

    Full Text Available In this article the concept, the materials and the exploitation potential of a photosynthetic microbial electrochemical cell for the production of hydrogen driven by solar power are investigated. In a photosynthetic microbial electrochemical cell, which is based on photosynthetic microorganisms confined to an anode and heterotrophic bacteria confined to a cathode, water is split by bacteria hosted in the anode bioactive film. The generated electrons are conveyed through external “bio-appendages” developed by the bacteria to transparent nano-pillars made of indium tin oxide (ITO, Fluorine-doped tin oxide (FTO or other conducting materials, and then transferred to the cathode. On the other hand, the generated protons diffuse to the cathode via a polymer electrolyte membrane, where they are reduced by the electrons by heterotrophic bacteria growing attached to a similar pillared structure as that envisaged for the anode and supplemented with a specific low cost substrate (e.g., organic waste, anaerobic digestion outlet. The generated oxygen is released to the atmosphere or stored, while the produced pure hydrogen leaves the electrode through the porous layers. In addition, the integration of the photosynthetic microbial electrochemical cell system with dark fermentation as acidogenic step of anaerobic digester, which is able to produce additional H2, and the use of microbial fuel cell, feed with the residues of dark fermentation (mainly volatile fatty acids, to produce the necessary extra-bias for the photosynthetic microbial electrochemical cell is here analyzed to reveal the potential benefits to this novel integrated technology.

  18. Chromatic adaptation of photosynthetic membranes.

    Science.gov (United States)

    Scheuring, Simon; Sturgis, James N

    2005-07-15

    Many biological membranes adapt in response to environmental conditions. We investigated how the composition and architecture of photosynthetic membranes of a bacterium change in response to light, using atomic force microscopy. Despite large modifications in the membrane composition, the local environment of core complexes remained unaltered, whereas specialized paracrystalline light-harvesting antenna domains grew under low-light conditions. Thus, the protein mixture in the membrane shows eutectic behavior and can be mimicked by a simple model. Such structural adaptation ensures efficient photon capture under low-light conditions and prevents photodamage under high-light conditions.

  19. A novel carotenoid 1,2-hydratase (CruF) from two species of the non-photosynthetic bacterium Deinococcus.

    Science.gov (United States)

    Sun, Zongtao; Shen, Shaochuan; Wang, Chao; Wang, Hu; Hu, Yaping; Jiao, Jiandong; Ma, Tingting; Tian, Bing; Hua, Yuejin

    2009-08-01

    A novel carotenoid 1,2-hydratase (CruF) responsible for the C-1',2' hydration of gamma-carotene was identified in the non-photosynthetic bacteria Deinococcus radiodurans R1 and Deinococcus geothermalis DSM 11300. Gene expression and disruption experiments demonstrated that dr0091 and dgeo2309 encode CruF in D. radiodurans and D. geothermalis, respectively. Their homologues were also found in the genomes of cyanobacteria, and exhibited little homology to the hydroxyneurosporene synthase (CrtC) proteins found mainly in photosynthetic bacteria. Phylogenetic analysis showed that CruF homologues form a separate family, which is evolutionarily distant from the known CrtC family.

  20. Gem-quality Turkish purple jade: Geological and mineralogical characteristics

    Science.gov (United States)

    Hatipoğlu, Murat; Başevirgen, Yasemin; Chamberlain, Steven C.

    2012-02-01

    In the Harmancık-Bursa region of the western Anatolia (Turkey), an extensive contact metamorphic aureole at the border between the Late Mesozoic coherent metaclastic rocks of blueschist facies and the Early Senozoic intrusive granodiorite stock hosts an interesting and unique gem material with a mineral assemblage consisting mainly of jadeite, quartz, orthoclase, epidote, chloritoid, and phlogopite as identified by X-ray diffraction spectroscopy and polarized-light microscopy. In addition, chemical analyses performed with X-ray fluorescence and inductive-coupled plasma-atomic emission spectroscopy show that the mass of the metamorphic aureole has a silica-rich, calc-alkaline chemical content. Therefore, some rock building elements (such as Al, Ca, Na, K, P, Sr, and B of which characterize an acidic-neutral rock formation) and trace elements (such as Fe, Cr, Mn, Be, Cu, Ga, La, Ni, Pb, and Zn) are remarkable high ratios. Pale purple-colored gem material of this composition appears to be unique to Turkey, also is only found in one narrow provenance in Turkey. Therefore, it is specially called "Turkish (and/or Anatolian) purple jade" on the worldwide gem market. Even though the mineral jadeite is the principal constituent, 40% by volume as determined with petrographic thin-section examination under a polarized-light microscope, the material cannot be considered pure jadeite. Specific gravity measurements of the jade using a hydrostatic balance confirm that it has a heterogeneous structure. The measured average specific gravity of 3.04, is significantly lower than the normal range for characterized jadeites of 3.24-3.43. Turkish purple jade samples were examined in detail using dispersive confocal micro-Raman spectroscopy (DCμRS) as well as other well-known analytical methods. The resulting strong micro-Raman bands that peaked at 1038, 984, 697, 571, 521, 464, 430, 372, 326, 307, 264, and 201 cm -1 are characteristics of the Turkish purple jade. The first most

  1. 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

  2. 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 r

  3. Two-dimensional protonic percolation on lightly hydrated purple membrane.

    Science.gov (United States)

    Rupley, J A; Siemankowski, L; Careri, G; Bruni, F

    1988-12-01

    The capacitance and dielectric loss factor were measured for a sample of purple membrane of Halobacterium halobium as a function of hydration level (0.017 to >0.2 g of water/g of membrane) and frequency (10 kHz to 10 MHz). The capacitance and the derived conductivity show explosive growth above a threshold hydration level, h(c) approximately 0.0456. The conductivity shows a deuterium isotope effect, H/(2)H = 1.38, in close agreement with expectation for a protonic process. The level h(c) is frequency independent and shows no deuterium isotope effect. These properties are analogous to those found for lysozyme in a related study. Protonic conduction for the purple membrane can be considered, as for lysozyme, within the framework of a percolation model. The critical exponent, t, which describes the conductivity of a percolative system near the threshold, has the value 1.23. This number is in close agreement with expectation from theory for a two-dimensional percolative process. The dielectric properties of the purple membrane are more complex than those of lysozyme, seen in the value of h(c) and in the frequency and hydration dependence of the loss factor. There appear to be preferred regions of proton conduction. The percolation model is based upon stochastic behavior of a system partially populated with conducting elements. This model suggests that ion transport in membranes and its control can be based on pathways formed of randomly connected conducting elements and that a fixed geometry (a proton wire) is not the only possible basis for a mechanism of conduction.

  4. A Psychoanalytic Reading of Celie in The Color Purple

    Institute of Scientific and Technical Information of China (English)

    蔡培琳

    2014-01-01

    This article explores the protagonist, Celie, in Alice Walker’s The Color Purple. Celie who is ugly, lacks of mother’s love, and oppressed in a universe of men. She admires Shug who is a beautiful woman. According to Lacan ’s theory, Celie’s love for Shug is a metonymic hunting for her mother’s body. Celie’s hunting process is along the metonymic chain of signifiers. And finally Celie finds her happiness even though the chain of signifiers continues.

  5. Antioxidant effect of Purple basil(Lamiaceae Phenolics

    Directory of Open Access Journals (Sweden)

    Mohammadi Mastaneh

    2014-12-01

    Full Text Available Plants used in folk and traditional medicines have been accepted as therapeutic drug development in modern medicine. SinceOcimum basilicum cv. dark opal has been used in Persian traditional medicine and many Iranian dishes,it was considered important to determine the reductive capacity of the purple basil oils and extracts, as this may indicate their potential as antioxidants. Results indicated that the extracts have more powerful antioxidant activity than the oils.Also,the phytochemical analysis of the extracts has led to the identification of 3 phenolic. Our study, partially validates the traditional use of this medicinal herb as complementary medicine.

  6. Purple sweet potato colour--a potential therapy for galactosemia?

    Science.gov (United States)

    Timson, David J

    2014-06-01

    Galactosemia is an inherited metabolic disease in which galactose is not properly metabolised. There are various theories to explain the molecular pathology, and recent experimental evidence strongly suggests that oxidative stress plays a key role. High galactose diets are damaging to experimental animals and oxidative stress also plays a role in this toxicity which can be alleviated by purple sweet potato colour (PSPC). This plant extract is rich in acetylated anthocyanins which have been shown to quench free radical production. The objective of this Commentary is to advance the hypothesis that PSPC, or compounds therefrom, may be a viable basis for a novel therapy for galactosemia.

  7. The interaction between purple membrane and membrane lipid

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Bacteriorhodopsin in purple membrane was reconstituted into different lipid vesicles. The effect of three different lipids on the structure and function of bacteriorhodopsin in lipid vesicles was studied by the observation on freeze-fracture eletron microscopy, the rotational diffusion of bacteriorhodopsin in lipid vesicles, the measurement of absorption spectrum, and the absorbance change with time. For these prepared samples, the results showed that DMPC was the stable lipid environment of bacteriorhodopsin; egg-pc causeed the loss of retinal chromophore of bacteriorhodopsin and it was not reversible change, cholesterol could stabilize the bacteriorhodopsin in lipid environment,but it caused the aggregation of bacteriorhodopsin.

  8. Two-dimensional protonic percolation on lightly hydrated purple membrane

    OpenAIRE

    Rupley, John A.; Siemankowski, Linda; Careri, Giorgio; Bruni, Fabio

    1988-01-01

    The capacitance and dielectric loss factor were measured for a sample of purple membrane of Halobacterium halobium as a function of hydration level (0.017 to >0.2 g of water/g of membrane) and frequency (10 kHz to 10 MHz). The capacitance and the derived conductivity show explosive growth above a threshold hydration level, hc ≈ 0.0456. The conductivity shows a deuterium isotope effect, H/2H = 1.38, in close agreement with expectation for a protonic process. The level hc is frequency independe...

  9. Research on purple seed stain of soybean: germplasm screening and genetic resistance

    Science.gov (United States)

    Soybean purple seed stain (PSS) causes seed decay and purple seed discoloration, resulting in overall poor seed quality and reduced market grade and value. It is a prevalent disease that also affects seed vigor and stand establishment. PSS is caused by the fungus Cercospora kikuchii and other Cercos...

  10. Screening a diverse soybean germplasm collection for reaction to purple seed stain caused by Cercospora kikuchii

    Science.gov (United States)

    Purple seed stain (PSS), caused by Cercospora kikuchii, is a prevalent soybean disease that causes latent seed infection, seed decay, purple seed discoloration, and overall quality deterioration. The objective of this research was to screen soybean accessions from the USDA germplasm collection for r...

  11. Anthocyanins and flavonols are responsible for purple color of Lablab purpureus (L.) sweet pods.

    Science.gov (United States)

    Cui, Baolu; Hu, Zongli; Zhang, Yanjie; Hu, Jingtao; Yin, Wencheng; Feng, Ye; Xie, Qiaoli; Chen, Guoping

    2016-06-01

    Lablab pods, as dietary vegetable, have high nutritional values similar to most of edible legumes. Moreover, our studies confirmed that purple lablab pods contain the natural pigments of anthocyanins and flavonols. Compared to green pods, five kinds of anthocyanins (malvidin, delphinidin and petunidin derivatives) were found in purple pods by HPLC-ESI-MS/MS and the major contents were delphinidin derivatives. Besides, nine kinds of polyphenol derivatives (quercetin, myricetin, kaempferol and apigenin derivatives) were detected by UPLC-ESI-MS/MS and the major components were quercetin and myricetin derivatives. In order to discover their molecular mechanism, expression patterns of biosynthesis and regulatory gens of anthocyanins and flavonols were investigated. Experimental results showed that LpPAL, LpF3H, LpF3'H, LpDFR, LpANS and LpPAP1 expressions were significantly induced in purple pods compared to green ones. Meanwhile, transcripts of LpFLS were more abundant in purple pods than green or yellow ones, suggestind that co-pigments of anthocyanins and flavonols are accumulated in purple pods. Under continuously dark condition, no anthocyanin accumulation was detected in purple pods and transcripts of LpCHS, LpANS, LpFLS and LpPAP1 were remarkably repressed, indicating that anthocyanins and flavonols biosynthesis in purple pods was regulated in light-dependent manner. These results indicate that co-pigments of anthocyanins and flavonols contribute to purple pigmentations of pods.

  12. Long Noncoding RNA PURPL Suppresses Basal p53 Levels and Promotes Tumorigenicity in Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Xiao Ling Li

    2017-09-01

    Full Text Available Basal p53 levels are tightly suppressed under normal conditions. Disrupting this regulation results in elevated p53 levels to induce cell cycle arrest, apoptosis, and tumor suppression. Here, we report the suppression of basal p53 levels by a nuclear, p53-regulated long noncoding RNA that we termed PURPL (p53 upregulated regulator of p53 levels. Targeted depletion of PURPL in colorectal cancer cells results in elevated basal p53 levels and induces growth defects in cell culture and in mouse xenografts. PURPL associates with MYBBP1A, a protein that binds to and stabilizes p53, and inhibits the formation of the p53-MYBBP1A complex. In the absence of PURPL, MYBBP1A interacts with and stabilizes p53. Silencing MYBBP1A significantly rescues basal p53 levels and proliferation in PURPL-deficient cells, suggesting that MYBBP1A mediates the effect of PURPL in regulating p53. These results reveal a p53-PURPL auto-regulatory feedback loop and demonstrate a role for PURPL in maintaining basal p53 levels.

  13. Quantum coherence in photosynthetic complexes

    Energy Technology Data Exchange (ETDEWEB)

    Calhoun, Tessa R.; Fleming, Graham R. [Department of Chemistry, University of California, Berkeley, CA 94720 (United States); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2011-04-15

    The initial steps of photosynthesis require the absorption and subsequent transfer of energy through an intricate network of pigment-protein complexes. Held within the protein scaffold of these complexes, chromophore molecules are densely packed and fixed in specific geometries relative to one another resulting in Coulombic coupling. Excitation energy transfer through these systems can be accomplished with near unity quantum efficiency [Wraight and Clayton, Biochim. Biophys. Acta 333, 246 (1974)]. While replication of this feat is desirable for artificial photosynthesis, the mechanism by which nature achieves this efficiency is unknown. Recent experiments have revealed the presence of long-lived quantum coherences in photosynthetic pigment-protein complexes spanning bacterial and plant species with a variety of functions and compositions. Its ubiquitous presence and wavelike energy transfer implicate quantum coherence as key to the high efficiency achieved by photosynthesis. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Tocopherol functions in photosynthetic organisms.

    Science.gov (United States)

    Maeda, Hiroshi; DellaPenna, Dean

    2007-06-01

    During the past decade, the genes required for tocopherol (vitamin E) synthesis in plants and cyanobacteria have been identified. A series of mutants in which specific pathway steps are disrupted have been generated, providing new insights into tocopherol functions in photosynthetic organisms. Tocopherols are essential for controlling non-enzymatic lipid peroxidation during seed dormancy and seedling germination. Their absence results in elevated levels of malondialdehyde and phytoprostanes, and in inappropriate activation of plant defense responses. Surprisingly, tocopherol deficiency in mature leaves has limited consequences under most abiotic stresses, including high intensity light stress. The cell wall development of phloem transfer cells under cold conditions is, however, severely impaired in mature leaves of tocopherol-deficient mutants, indicating that tocopherols are required for proper adaptation of phloem loading at low temperatures.

  15. The photosynthetic apparatus and its regulation in the aerobic gammaproteobacterium Congregibacter litoralis gen. nov., sp. nov.

    Directory of Open Access Journals (Sweden)

    Stefan Spring

    Full Text Available BACKGROUND: There is accumulating evidence that in some marine environments aerobic bacteriochlorophyll a-producing bacteria represent a significant part of the microbial population. The interaction of photosynthesis and carbon metabolism in these interesting bacteria is still largely unknown and requires further investigation in order to estimate their contribution to the marine carbon cycle. METHODOLOGY/PRINCIPAL FINDINGS: Here, we analyzed the structure, composition and regulation of the photosynthetic apparatus in the obligately aerobic marine gammaproteobacterium KT71(T. Photoheterotrophically grown cells were characterized by a poorly developed lamellar intracytoplasmic membrane system, a type 1 light-harvesting antenna complex and a photosynthetic reaction center associated with a tetraheme cytochrome c. The only photosynthetic pigments produced were bacteriochlorophyll a and spirilloxanthin. Under semiaerobic conditions KT71(T cells expressing a photosynthetic apparatus showed a light-dependent increase of growth yield in the range of 1.3-2.5 fold. The expression level of the photosynthetic apparatus depended largely on the utilized substrate, the intermediary carbon metabolism and oxygen tension. In addition, pigment synthesis was strongly influenced by light, with blue light exerting the most significant effect, implicating that proteins containing a BLUF domain may be involved in regulation of the photosynthetic apparatus. Several phenotypic traits in KT71(T could be identified that correlated with the assumed redox state of growing cells and thus could be used to monitor the cellular redox state under various incubation conditions. CONCLUSIONS/SIGNIFICANCE: In a hypothetical model that explains the regulation of the photosynthetic apparatus in strain KT71(T we propose that the expression of photosynthesis genes depends on the cellular redox state and is maximal under conditions that allow a balanced membrane redox state. So far

  16. Purple drank prevalence and characteristics of misusers of codeine cough syrup mixtures.

    Science.gov (United States)

    Agnich, Laura E; Stogner, John M; Miller, Bryan Lee; Marcum, Catherine D

    2013-09-01

    A mixture of codeine cough syrup with alcohol and/or a soft drink known as "purple drank" has gained media attention in recent years as a drug associated with professional athletes and southern rap music. The existing research on purple drank consumption has primarily utilized samples of African Americans residing in the Houston, Texas area. This is the first scholarly study of purple drank use outside of the Houston, Texas area among a general population of young adults, and indicates that purple drank use is not limited to African American males. The findings depict higher odds of the use of purple drank among other racial and ethnic groups, males, and homosexual, bisexual, and transgender college students from urban areas.

  17. Anthocyanin Accumulation and Molecular Analysis of Correlated Genes in Purple Kohlrabi (Brassica oleracea var. gongylodes L.).

    Science.gov (United States)

    Zhang, Yanjie; Hu, Zongli; Zhu, Mingku; Zhu, Zhiguo; Wang, Zhijin; Tian, Shibing; Chen, Guoping

    2015-04-29

    Kohlrabi (Brassica oleracea var. gongylodes L.) is an important dietary vegetable cultivated and consumed widely for the round swollen stem. Purple kohlrabi shows abundant anthocyanin accumulation in the leaf and swollen stem. Here, different kinds of anthocyanins were separated and identified from the purple kohlrabi cultivar (Kolibri) by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry. In order to study the molecular mechanism of anthocyanin biosynthesis in purple kohlrabi, the expression of anthocyanin biosynthetic genes and regulatory genes in purple kohlrabi and a green cultivar (Winner) was examined by quantitative PCR. In comparison with the colorless parts in the two cultivars, most of the anthocyanin biosynthetic genes and two transcription factors were drastically upregulated in the purple tissues. To study the effects of light shed on the anthocyanin accumulation of kohlrabi, total anthocyanin contents and transcripts of associated genes were analyzed in sprouts of both cultivars grown under light and dark conditions.

  18. Calculation of the radiative properties of photosynthetic microorganisms

    Science.gov (United States)

    Dauchet, Jérémi; Blanco, Stéphane; Cornet, Jean-François; Fournier, Richard

    2015-08-01

    photosynthetic bacteria, cyanobacteria and eukaryotic microalgae. The obtained results are in very good agreement with the experimental measurements when the shape of the microorganisms is well described (in comparison to the standard volume-equivalent sphere approximation). As a main perspective, the consideration of the helical shape of Arthrospira platensis appears to be a key to an accurate estimation of its radiative properties. On the whole, the presented methodological chain also appears of great interest for other scientific communities such as atmospheric science, oceanography, astrophysics and engineering.

  19. Excited state dynamics in photosynthetic reaction center and light harvesting complex 1

    Science.gov (United States)

    Strümpfer, Johan; Schulten, Klaus

    2012-08-01

    Key to efficient harvesting of sunlight in photosynthesis is the first energy conversion process in which electronic excitation establishes a trans-membrane charge gradient. This conversion is accomplished by the photosynthetic reaction center (RC) that is, in case of the purple photosynthetic bacterium Rhodobacter sphaeroides studied here, surrounded by light harvesting complex 1 (LH1). The RC employs six pigment molecules to initiate the conversion: four bacteriochlorophylls and two bacteriopheophytins. The excited states of these pigments interact very strongly and are simultaneously influenced by the surrounding thermal protein environment. Likewise, LH1 employs 32 bacteriochlorophylls influenced in their excited state dynamics by strong interaction between the pigments and by interaction with the protein environment. Modeling the excited state dynamics in the RC as well as in LH1 requires theoretical methods, which account for both pigment-pigment interaction and pigment-environment interaction. In the present study we describe the excitation dynamics within a RC and excitation transfer between light harvesting complex 1 (LH1) and RC, employing the hierarchical equation of motion method. For this purpose a set of model parameters that reproduce RC as well as LH1 spectra and observed oscillatory excitation dynamics in the RC is suggested. We find that the environment has a significant effect on LH1-RC excitation transfer and that excitation transfers incoherently between LH1 and RC.

  20. Single-molecule spectroscopy reveals photosynthetic LH2 complexes switch between emissive states.

    Science.gov (United States)

    Schlau-Cohen, Gabriela S; Wang, Quan; Southall, June; Cogdell, Richard J; Moerner, W E

    2013-07-01

    Photosynthetic organisms flourish under low light intensities by converting photoenergy to chemical energy with near unity quantum efficiency and under high light intensities by safely dissipating excess photoenergy and deleterious photoproducts. The molecular mechanisms balancing these two functions remain incompletely described. One critical barrier to characterizing the mechanisms responsible for these processes is that they occur within proteins whose excited-state properties vary drastically among individual proteins and even within a single protein over time. In ensemble measurements, these excited-state properties appear only as the average value. To overcome this averaging, we investigate the purple bacterial antenna protein light harvesting complex 2 (LH2) from Rhodopseudomonas acidophila at the single-protein level. We use a room-temperature, single-molecule technique, the anti-Brownian electrokinetic trap, to study LH2 in a solution-phase (nonperturbative) environment. By performing simultaneous measurements of fluorescence intensity, lifetime, and spectra of single LH2 complexes, we identify three distinct states and observe transitions occurring among them on a timescale of seconds. Our results reveal that LH2 complexes undergo photoactivated switching to a quenched state, likely by a conformational change, and thermally revert to the ground state. This is a previously unobserved, reversible quenching pathway, and is one mechanism through which photosynthetic organisms can adapt to changes in light intensities.

  1. Fenton Discoloration of Ultrasonicated Purple Cactus Pear Juice.

    Science.gov (United States)

    Reyes-Hernández, Isidro; Cruz-Cansino, Nelly Del S; Santander-Martínez, Ingrid Renata; Alanís-García, Ernesto; Delgado-Olivares, Luis; Ramírez-Moreno, Esther; Ariza-Ortega, José A; Omaña-Covarrubias, Ariana; Torres-Valencia, Jesús Martín; Manríquez-Torres, José de Jesús

    2017-08-15

    The aim of this study was to evaluate the stability of color, betaxanthin, and betacyanin pigments in the presence of Cu(II)-dependent hydroxyl radicals (HO•) from ultrasonicated purple cactus pear juice at amplitudes of 40%, 60%, and 80%, in comparison to untreated sample. L* parameter of juice treated at 40% and 80% amplitude for 25 and 15 min, respectively (11.3 and 9.3, respectively), were significantly higher compared to the control; b* and hue parameters of juice treated at 80%, 25 min showed values of 1.7 and 0.1, respectively. Color differences (ΔE) were lower (juices treated at high amplitude (80%) and short times (3-5 min). Juice treated at 40% 15 min, 60% 25 min, 80% 15 and 25 min presented high values of betacyanins (281.7 mg·L(-1), 255.9 mg·L(-1), 294.4 mg·L(-1), and 276.7 mg·L(-1), respectively). Betaxanthin values were higher in the juices treated at 40% 5 min and 80% 15 and 25 min (154.2 mg·L(-1), 135.2 mg·L(-1), and 128.5 mg·L(-1), respectively). Purple cactus pear juice exhibited significant chelating activity of copper ions and great stability when exposed to HO•.

  2. Effects of Several Purple Potato Additions on Bread Quality

    Directory of Open Access Journals (Sweden)

    Bădărău Carmen Liliana

    2016-04-01

    Full Text Available Potato cultivars with purple flesh represent an efficient and natural source of antioxidants, this vegetable having high content in polyphenols (especially anthocyanin pigments. The research goal of this work was to evaluate the anthocyanin and polyphenols content of several Romanian potato varieties (Albastru-Violet de Gălănești and Christian and the effects of these potatoes (add to dough in different proportions on several bread quality indicators. The bread quality depends on physical and chemical properties and on several signs like: flavor and taste, external appearance, crumb porosity and texture, bread’s volume. In this research experiment, beside the total polyphenols and anthocyanin content, the analysis performed on bread (prepared using different potatoes addition 5%, 15% and 30% were sensorial and physic chemical analysis (product volume, crumb porosity, height/diameter ratio, moist and acidity. Experimental results indicated that 15% purple potato cultivar added on the dough was the most indicate proportion to be used in bread processing.

  3. The kinetic model for slow photoinduced electron transport in the reaction centers of purple bacteria

    Science.gov (United States)

    Serdenko, T. V.; Barabash, Y. M.; Knox, P. P.; Seifullina, N. Kh.

    2016-06-01

    The present work is related to the investigation of slow kinetics of electron transport in the reaction centers (RCs) of Rhodobacter sphaeroides. Experimental data on the absorption kinetics of aqueous solutions of reaction centers at different modes of photoexcitation are given. It is shown that the kinetics of oxidation and reduction of RCs are well described by the sum of three exponential functions. This allows to suggest a two-level kinetic model for electron transport in the RC as a system of four electron-conformational states which correspond to three balance differential equations combined with state equation. The solution of inverse problem made it possible to obtain the rate constant values in kinetic equations for different times and intensities of exciting light. Analysis of rate constant values in different modes of RC excitation allowed to suggest that two mechanisms of structural changes are involved in RC photo-oxidation. One mechanism leads to the increment of the rate of electron return, another one—to its drop. Structural changes were found out to occur in the RCs under incident light. After light was turned off, the reduction of RCs was determined by the second mechanism.

  4. [Effects of light quality on photosynthetic pigment contents and photosynthetic characteristics of peanut seedling leaves].

    Science.gov (United States)

    Yan, Meng-Meng; Wang, Ming-Lun; Wang, Hong-Bo; Wang, Yue-Fu; Zhao, Chang-Xing

    2014-02-01

    This study explored the effects of different light quality on photosynthetic pigment contents and photosynthetic characteristics of peanut (Qinhua 6) seedling leaves. The results showed that, compared with natural light, blue light (445-470 nm) could significantly improve the specific leaf area (SLA), chlorophyll a/b value and carotenoid content of peanut seedlings. Meanwhile, the net photosynthetic rate, stomatal conductance, and transpiration rate were higher, the intercellular CO2 content was lower, and the photosynthetic efficiency was improved significantly under blue light. Red light (610-660 nm) could improve the chlorophyll content significantly, and reduce SLA, chlorophyll a/b value and carotenoid content, with a lower photosynthetic efficiency than natural light. Green light (515-520 nm) and yellow light (590-595 nm) were not conducive to photosynthetic pigment accumulation of leaves, and significantly inhibited leaf photosynthesis of peanut seedlings.

  5. Photoelectrochemical cells based on photosynthetic systems: a review

    Directory of Open Access Journals (Sweden)

    Roman A. Voloshin

    2015-06-01

    Full Text Available Photosynthesis is a process which converts light energy into energy contained in the chemical bonds of organic compounds by photosynthetic pigments such as chlorophyll (Chl a, b, c, d, f or bacteriochlorophyll. It occurs in phototrophic organisms, which include higher plants and many types of photosynthetic bacteria, including cyanobacteria. In the case of the oxygenic photosynthesis, water is a donor of both electrons and protons, and solar radiation serves as inexhaustible source of energy. Efficiency of energy conversion in the primary processes of photosynthesis is close to 100%. Therefore, for many years photosynthesis has attracted the attention of researchers and designers looking for alternative energy systems as one of the most efficient and eco-friendly pathways of energy conversion. The latest advances in the design of optimal solar cells include the creation of converters based on thylakoid membranes, photosystems, and whole cells of cyanobacteria immobilized on nanostructured electrode (gold nanoparticles, carbon nanotubes, nanoparticles of ZnO and TiO2. The mode of solar energy conversion in photosynthesis has a great potential as a source of renewable energy while it is sustainable and environmentally safety as well. Application of pigments such as Chl f and Chl d (unlike Chl a and Chl b, by absorbing the far red and near infrared region of the spectrum (in the range 700-750 nm, will allow to increase the efficiency of such light transforming systems. This review article presents the last achievements in the field of energy photoconverters based on photosynthetic systems.

  6. Phytochemical Content of Some Black (Morus nigra L. and Purple (Morus rubra L. Mulberry Genotypes

    Directory of Open Access Journals (Sweden)

    Murat Tosun

    2010-01-01

    Full Text Available Bright black (Morus nigra and purple mulberry (Morus rubra are particularly desirable fruits in Turkey. More recently, the interest in these bright black and purple mulberry fruits has also increased because of the popularization of healthy properties of these fruits. The study was carried out in 2008 aiming to determine the antioxidant activity (ferric reducing ability of plasma, FRAP, total phenolic, total anthocyanin, mineral, soluble solid, vitamin C, and total acid content of four black and four purple mulberry genotypes grown in Turkey. The results show that black mulberry genotypes have a higher bioactive content than purple mulberry genotypes. The average total phenolic content and total anthocyanins of black mulberry genotypes were 2149 μg of gallic acid equivalent (GAE per g and 719 μg of cyanidin 3-glucoside equivalent (Cy 3-glu per g of fresh mass. In purple mulberry, these values were for GAE 1690 μg/g and for Cy 3-glu 109 μg/g on fresh mass basis. The average antioxidant activity of black mulberry genotypes was also found to be higher than that of the purple ones according to FRAP assay (Trolox equivalent (TE per fresh mass of black and purple mulberries was 13.35 and 6.87 μmol/g, respectively.

  7. Hybrid system of semiconductor and photosynthetic protein.

    Science.gov (United States)

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

    2014-08-29

    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.

  8. Photosynthetic carbon monoxide metabolism by sugarcane leaves

    Energy Technology Data Exchange (ETDEWEB)

    Kortschak, H.P.; Nickell, L.G.

    1973-01-01

    The photosynthetic carbon monoxide metabolism by sugarcane was studied to determine whether substantial quantities of CO are removed from the air by fields in Hawaii. Leaves metabolized low CO concentrations photosynthetically, with sucrose as an end product. Rates of uptake were of the order of 10/sup -4/ power mg/d sq m/hr. This was to low to be significant in removing CO from the atmosphere.

  9. Synergistic Two-Photon Absorption Enhancement in Photosynthetic Light Harvesting

    Science.gov (United States)

    Chen, Kuo-Mei; Chen, Yu-Wei; Gao, Ting-Fong

    2012-06-01

    The grand scale fixation of solar energies into chemical substances by photosynthetic reactions of light-harvesting organisms provides Earth's other life forms a thriving environment. Scientific explorations in the past decades have unraveled the fundamental photophysical and photochemical processes in photosynthesis. Higher plants, green algae, and light-harvesting bacteria utilize organized pigment-protein complexes to harvest solar power efficiently and the resultant electronic excitations are funneled into a reaction center, where the first charge separation process takes place. Here we show experimental evidences that green algae (Chlorella vulgaris) in vivo display a synergistic two-photon absorption enhancement in their photosynthetic light harvesting. Their absorption coefficients at various wavelengths display dramatic dependence on the photon flux. This newly found phenomenon is attributed to a coherence-electronic-energy-transfer-mediated (CEETRAM) photon absorption process of light-harvesting pigment-protein complexes of green algae. Under the ambient light level, algae and higher plants can utilize this quantum mechanical mechanism to create two entangled electronic excitations adjacently in their light-harvesting networks. Concerted multiple electron transfer reactions in the reaction centers and oxygen evolving complexes can be implemented efficiently by the coherent motion of two entangled excitons from antennae to the charge separation reaction sites. To fabricate nanostructured, synthetic light-harvesting apparatus, the paramount role of the CEETRAM photon absorption mechanism should be seriously considered in the strategic guidelines.

  10. Appearance of new taxa: invertebrates, phytoplankton and bacteria in an alkaline, saline, meteorite crater lake, South Africa

    CSIR Research Space (South Africa)

    Oberholster, Paul J

    2009-04-01

    Full Text Available of purple sulphur bacteria in the lake. The absence of submerged and emergent aquatic macrophytes in the lake limits habitat diversity for attached diatoms in the littoral regions. Both the numbers of families and the density of the benthic invertebrates...

  11. Síndrome de la orina morada en bolsa en paciente anciana con suplementos nutricionales Purple urine bag syndrome in elderly woman with nutritional supplements

    Directory of Open Access Journals (Sweden)

    A. R. Domínguez Alegría

    2012-12-01

    Full Text Available El síndrome de la orina morada en bolsa es una entidad poco frecuente que afecta característicamente a mujeres de edad avanzada con sondaje vesical prolongado y debilitadas por enfermedades crónicas. La presencia de patología urológica previa, el encamamiento prolongado y el estreñimiento crónico son factores predisponentes. El color morado de la orina se debe a la presencia de elevadas concentraciones de bacterias con actividad indoxilsulfatasa/fosfatasa que se desarrollan en un ambiente alcalino en presencia de otros factores. En el caso que presentamos la administración de suplementos nutricionales ricos en triptófano tuvieron un papel relevante en la generación de este síndrome.The purple urine bag syndrome is a rare entity which typically affects elderly women with prolonged urinary catheterization and weakening chronic diseases. Other predisposing factors are previous urologic pathology, immobility syndrome and chronic constipation. The purple color is due to the presence of high loads of bacteria with sulphatase - phosphatase activity which develop in an alkaline environment as well as the presence of other factors. In the case we present the administration of nutritional supplements containing tryptophan conditioned the generation of this syndrome.

  12. Updated Multichannel Infrared Solar Spectrograph at Purple Mountain Observatory

    Institute of Scientific and Technical Information of China (English)

    黎辉; 尤建圻; 吴琴娣; 于兴凤

    2002-01-01

    We describe the newly updated multichannel infrared solar spectrograph at the Purple Mountain Observatory that now uses three Apogee APTp grade i scientific CCDs as its detectors and works at three wavelengths, He I 10830 , Call 8542 and Ha, simultaneously. The spectral resolutions of these lines are 0.04776, 0.05113 and 0.05453 per pixel, respectively. Some observation examples are presented. The observed profiles of the three lines demonstrate that redshift and asymmetry exist in the impulsive phase of the given disc flare and both blueshift and redshift exist in the presented flare spray in the impulsive phase of a limb flare. They also indicate that horizontal expansion exists in addition to the quick radial motion in the flare spray.

  13. Dielectric dispersion and protonic conduction in hydrated purple membrane.

    Science.gov (United States)

    Kovács, I; Váró, G

    1988-01-01

    Dielectric dispersion effects were studied in purple membranes of different hydration levels. The capacitance and conductivity were measured over the frequency range of 10(2) Hz to 10(5) Hz. With increase in the hydration level, the conductivity increases sharply above the critical hydration of hc = 0.06 g H2O/g protein. This critical hydration is close to the extent of the first continuous strongly bound water layer and is interpreted as the threshold for percolative proton transfer. The capacitance increases continuously with increasing hydration and a larger increase above the water content of 0.1 g H2O/g protein can be seen only at low frequencies. Maxwell-Wagner relaxation also appears above this hydration, showing the presence of a bulk water phase.

  14. Protein-lipid interactions in the purple bacterial reaction centre.

    Science.gov (United States)

    Jones, Michael R; Fyfe, Paul K; Roszak, Aleksander W; Isaacs, Neil W; Cogdell, Richard J

    2002-10-11

    The purple bacterial reaction centre uses the energy of sunlight to power energy-requiring reactions such as the synthesis of ATP. During the last 20 years, a combination of X-ray crystallography, spectroscopy and mutagenesis has provided a detailed insight into the mechanism of light energy transduction in the bacterial reaction centre. In recent years, structural techniques including X-ray crystallography and neutron scattering have also been used to examine the environment of the reaction centre. This mini-review focuses on recent studies of the surface of the reaction centre, and briefly discusses the importance of the specific protein-lipid interactions that have been resolved for integral membrane proteins.

  15. Sulfur cycling and metabolism of phototrophic and filamentous sulfur bacteria

    Science.gov (United States)

    Guerrero, R.; Brune, D.; Poplawski, R.; Schmidt, T. M.

    1985-01-01

    Phototrophic sulfur bacteria taken from different habitate (Alum Rock State Park, Palo Alto salt marsh, and Big Soda Lake) were grown on selective media, characterized by morphological and pigment analysis, and compared with bacteria maintained in pure culture. A study was made of the anaerobic reduction of intracellular sulfur globules by a phototrophic sulfur bacterium (Chromatium vinosum) and a filamentous aerobic sulfur bacterium (Beggiatoa alba). Buoyant densities of different bacteria were measured in Percoll gradients. This method was also used to separate different chlorobia in mixed cultures and to assess the relative homogeneity of cultures taken directly or enriched from natural samples (including the purple bacterial layer found at a depth of 20 meters at Big Soda Lake.) Interactions between sulfide oxidizing bacteria were studied.

  16. Bacteria Provide Cleanup of Oil Spills, Wastewater

    Science.gov (United States)

    2010-01-01

    Through Small Business Innovation Research (SBIR) contracts with Marshall Space Flight Center, Micro-Bac International Inc., of Round Rock, Texas, developed a phototrophic cell for water purification in space. Inside the cell: millions of photosynthetic bacteria. Micro-Bac proceeded to commercialize the bacterial formulation it developed for the SBIR project. The formulation is now used for the remediation of wastewater systems and waste from livestock farms and food manufacturers. Strains of the SBIR-derived bacteria also feature in microbial solutions that treat environmentally damaging oil spills, such as that resulting from the catastrophic 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico.

  17. Use of purple durum wheat to produce naturally functional fresh and dry pasta.

    Science.gov (United States)

    Ficco, Donatella Bianca Maria; De Simone, Vanessa; De Leonardis, Anna Maria; Giovanniello, Valentina; Del Nobile, Matteo Alessandro; Padalino, Lucia; Lecce, Lucia; Borrelli, Grazia Maria; De Vita, Pasquale

    2016-08-15

    In this study, the effects of different milling procedures (roller-milling vs. stone-milling) and pasta processing (fresh vs. dried spaghetti), and cooking on the antioxidant components and sensory properties of purple durum wheat were investigated. Milling and pasta processing were performed using one purple and one conventional non-pigmented durum wheat genotypes, and the end-products were compared with commercial pasta. The results show that the stone milling process preserved more compounds with high health value (total fibre and carotenoids, and in the purple genotype, also anthocyanins) compared to roller-milling. The drying process significantly (ppasta production. The sensory properties of pasta from the purple genotype did not significantly differ from commercial wholemeal pasta, and its in vitro glycemic index was even lower. Thus, it is possible to consider this genetic material as a good ingredient for the production of functional foods from cereals naturally rich in bioactive compounds.

  18. Protection Island NWR: Initial Survey Instructions for Purple Martin Breeding Bird Survey

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Purple Martin (Progne subis) is listed as a Species of Concern by the State and is the focus of a citizen science restoration project designed to provide...

  19. Erosion and Sediment Production in Small Watershed in Purple Hilly Areas and Prevention Techniques

    Institute of Scientific and Technical Information of China (English)

    ZhangBao-hua; HeYu-rong; ZhouHong-yi; ZhuBo

    2003-01-01

    Purple Soil distributes extensively and mainly in China. Because of abundant easily weatherable parent rocks/materials and unstable soil structure, and also influenced by parent materials, usage systems, and slope gradients, erosion and sediment production of purple soils are very severe with main fashions of water erosion and gravitational erosion. Basing on observed data in small watersheds, rainfall erosivity,vegetation coverage, previous soil water content, flow and relating; factors such as climate, topograph of small watershed,land usage, and soil kinds are all the influence factors of erosion and erodibility of purple soil as well as sediment production and transport in small watershed of purple hilly areas.The effective technological countermeasures of ecosystem restoration, agricultural tillage for water conservation and erosion prevention, agriculture project, and soil changing for fertility and anti-erosion were provided.

  20. Erosion and Sediment Production in Small Watershed in Purple Hilly Areas and Prevention Techniques

    Institute of Scientific and Technical Information of China (English)

    Zhang Bao-hua; He Yu-rong; Zhou Hong-yi; Zhu Bo

    2003-01-01

    Purple Soil distributes extensively and mainly in China. Because of abundant easily weatherable parent rocks/materials and unstable soil structure, and also influenced by parent materials, usage systems, and slope gradients, erosion and sediment production of purple soils are very severe with main fashions of water erosion and gravitational erosion. Basing on observed data in small watersheds, rainfall erosivity,vegetation coverage, previous soil water content, flow and relating factors such as climate, topograph of small watershed,land usage, and soil kinds are all the influence factors of erosion and erodibility of purple soil as well as sediment production and transport in small watershed of purple hilly areas.The effective technological countermeasures of ecosystem restoration, agricultural tillage for water conservation and erosion prevention, agriculture project, and soil changing for fertility and anti-erosion were provided.

  1. The quantitative determination of the spectral distribution of phototactic sensitivity in the purple bacterium Rhodospirillum rubrum

    NARCIS (Netherlands)

    Milatz, J.M.W.; Manten, A.

    1953-01-01

    By using a compensation method, the action spectrum (spectral distribution of stimulating efficiency in a quantitative measure) of phototaxis in the purple bacterium Rhodospirillum rubrum (Esmarch) Molisch Strain 4 was determined. Two differently coloured adjacent small light fields were projected

  2. Anthocyanins in purple and blue wheat grains and in resulting bread: quantity, composition, and thermal stability.

    Science.gov (United States)

    Bartl, Pavel; Albreht, Alen; Skrt, Mihaela; Tremlová, Bohuslava; Ošťádalová, Martina; Šmejkal, Karel; Vovk, Irena; Ulrih, Nataša Poklar

    2015-01-01

    The anthocyanin composition of blue (Triticum aestivum L., cv. Skorpion) and purple wheat (Triticum aethiopicum JAKUBZ cv. Abyssinskaja arrasajta cv. Abyssinskaja arrasajta), cultivated in the Czech Republic, and of the prepared whole blue and purple wheat bread was determined. In blue and purple wheat, 19 and 26 anthocyanins, respectively, were tentatively identified by liquid chromatography and mass spectrometry. The total content of anthocyanins determined in blue and purple wheat was 9.26 and 13.23 mgkg(-1), respectively. The breads were baked at 240 and 180 °C. Some significant differences in anthocyanins content were observed between breads prepared at different baking temperatures. The content of cyanidin-3-glucoside, delphinidin-3-glucoside and pelargonidin-3-glucoside was determinated in starting material, whole meal flours and baked breads. These kinds of wheat are suitable for baking bread, since intake of anthocyanins may play an important role in the prevention of human diseases.

  3. Soil Aggregation and Its Relationship with Organic Carbon of Purple Soils in the Sichuan Basin, China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The interaction of soil aggregate dynamics with soil organic carbon is complex with varied spatio-temporal processes in macro-and micro-aggregates, This paper is to determine the aggregation of soil aggregates in purple soils (Regosols in FAO Taxonomy or Entisols in USDA Taxonomy) for four types of land use, cropland [com (Zea mays L.)], orchard (citrus), forestland (bamboo or cypress), and barren land (wild grass), and to explore their relationship with soil organic carbon in the Sichuan basin of southwestern China. Procedures and methods, including manual dry sieving procedure, Yoder's wet sieving procedure, pyrophosphates solution method, and Kachisky method, are used to acquire dry, wet, and chemically stable aggregates, and microaggregates. Light and heavy fractions of soil organic carbon were separated using 2.0 g mL-1 HgI2-KI mixed solution. The loosely, stably, and tightly combined organic carbon in heavy fraction were separated by extraction with 0.1 M NaOH and 0.1 M NaOH-0.1M Na4P2O7 mixed solution (pH 13). The results show that the contents of dry and wet macroaggregates > 0.25 mm in diameter were 974.1 and 900.0 g kg-1 highest in red brown purple soils under forestland, while 889.6 and 350.6 g kg-1 lowest in dark purple soil and lowest in grey brown purple soils under cropland, respectively. The chemical stability of macroaggregates was lowest in grey brown purple soil with 8.47% under cropland, and highest in red brown purple soil with 69.34% under barren land. The content of microaggregates in dark purple soils was 587 g kg-1 higher than brown purple soils, while 655 g kg-1 in red brown purple soils was similar to grey brown purple soils (651 g kg-1). Cropland conditions, only 38.4% of organic carbon was of the combined form, and 61.6% of that existed in light fraction. Forestland conditions, 90.7% of organic carbon in red brown purple soil was complexed with minerals as a form of humic substances. The contents and stability of wet aggregates >0.25 mm

  4. PS2013 Satellite Workshop on Photosynthetic Light-Harvesting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Niederman, Robert A. [Rutgers Univ., New Brunswick, NJ (United States); Blankenship, Robert E. [Washington Univ., St. Louis, MO (United States); Frank, Harry A. [Univ. of Connecticut, Storrs, CT (United States)

    2015-02-07

    represented a diverse international and multidisciplinary group, with over 160 individuals attending from a total of 17 different countries. Attendees came from a wide range of fields assuring that the widest possible interdisciplinary exchanges. They included prominent biochemists, biophysicists, plant physiologists, chemical physicists, as well as theoretical and computational physical chemists, who presented their research findings or to hear the latest advances in this very dynamic field. In the choice of speakers, a balance was created between established scientists and young, emerging researchers, given this opportunity to showcase their results. Sessions were held on electronic and vibrational coherence including coherent sharing of excitations among donor and acceptor molecules during excitation energy transfer, nonphotochemical quenching, acclimation to light environments, evolution, adaptation and biodiversity of light-harvesting pigment-protein complexes, their structure and membrane organization, spectroscopy and dynamics, as well as artificial antenna systems. A joint session was also held with the participants from the Cyanobacterial Satellite Conference. A special issue of Photosynthesis Research devoted to light harvesting (Volume 121, Issue No. 1, July 2014) has recently appeared which contains peer-reviewed original research contributions arising from talks and posters presented at the PS2013 Satellite Workshop on Photosynthetic Light-Harvesting Systems. Edited by the Organizers of the Workshop, Robert E. Blankenship, Harry A. Frank and Robert A. Niederman, it includes topics ranging from the isolation of new bacteriochlorophyll species from green bacteria, temperature effects on the excited states of the newly discovered chlorophyll (Chl) ƒ, new architectures for enhancing energy capture by biohybrid light-harvesting complexes, forces governing the formation of light-harvesting rings, spectroscopy of carotenoids of algae and diatoms and the supramolecular

  5. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria......, Thiomargarita namibiensis, with a diameter of 750 mum. All bacteria, including those that swim around in the environment, obtain their food molecules by molecular diffusion. Only the fastest and largest swimmers known, Thiovulum majus, are able to significantly increase their food supply by motility...... and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria...

  6. Anaerobic bacteria

    Science.gov (United States)

    Brook I, Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 297. Stedman's Online ...

  7. ACIDIC SOAKING AND STEAM BLANCHING RETAIN ANTHOCYANINS AND POLYPHENOLS IN PURPLE Dioscorea alata FLOUR

    OpenAIRE

    Nelis Imanningsih; Deddy Muchtadi; Tutik Wresdiyati; Nurheni Sri Palupi2); Komari

    2013-01-01

    Purple Dioscorea alata (DA) tuber has health benefits due to its bioactive anthocyanins, which belong to polyphenolic group. Tuber is commonly made into flour to optimize its uses, however, the anthocyanins undergo significant degradation during processing because of the endogenous polyphenol oxidase activities. This research investigated factors that retain anthocyanins and polyphenols in the purple DA flour as well as its antioxidant capacity. The types of treatments during milling process ...

  8. Fine mapping and candidate gene analysis of purple pericarp gene Pb in rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Purple rice is a type of rice with anthocyanins deposited in its grain pericarp. The rice Pb gene controlling purple pericarp character is known to be on chromosome 4, and the purple color is dominant over white color. In this study, we fine mapped the Pb gene using two F2 segregating populations, i.e. Pei'ai 64S (white) × Yunanheixiannuo (purple) and Pei'ai 64S × Chuanheinuo (purple). In the first-pass mapping, the Pb gene was located in the region downstream the SSR marker RM3820. In the fine mapping, the candidate region was saturated with InDel and CAPS markers developed specifically for this study. Eventually, the Pb gene was mapped within the 25-kb region delimited by the upstream marker RID3 and the downstream marker RID4. The delimited region contained two annotated genes, Ra and bhlh16 (TIGR Rice Genome, R.5). The former is a homologue of the Myc transcription factor Lc controlling anthocyanin biosynthesis in maize, and the latter is a homologue of the TT8 gene, which is also an Myc transcription factor gene controlling the pericarp pigmentation in Arabidopsis thaliana. Sequence analysis showed that the exon 7 of the Ra gene of Yunanheixiannuo and Chuanheinuo had a 2-bp (GT) deletion compared with those of the white rice varieties Pei'ai 64S, 9311 and Nipponbare. A CAPS marker, CAPSRa, was developed according to the GT deletion for analysis of the two F2 segregating populations and 106 rice lines. The results showed that all F2 plants with white pericarp, and all non-purple rice lines (63 white and 22 red) contained no GT deletion, but all 20 purple rice lines contained the GT deletion. These results suggested that the Ra gene may be the Pb gene and the purple pericarp characteristic of rice is caused by the GT deletion within exon 7 of the Ra gene.

  9. Tracing of backward energy transfer from LH1 to LH2 in photosynthetic membranes grown under high and low irradiation.

    Directory of Open Access Journals (Sweden)

    Lanzani G.

    2013-03-01

    Full Text Available By introducing derivative transient absorption spectroscopy, we obtain rate constants for backward and forward energy transfer between LH1 and LH2 complexes in purple bacterial membranes. We find that backward energy transfer is strongly reduced in membranes grown under low irradiation conditions, compared to high light grown ones. We conclude that backward energy transfer is managed actively by the bacteria to avoid LH1 exciton deactivation under high irradiation conditions. The analytical method is generally applicable to excitonically coupled systems.

  10. Non-invasive investigation on a VI century purple codex from Brescia, Italy

    Science.gov (United States)

    Aceto, Maurizio; Idone, Ambra; Agostino, Angelo; Fenoglio, Gaia; Gulmini, Monica; Baraldi, Pietro; Crivello, Fabrizio

    2014-01-01

    Purple codices are among the most relevant and prestigious book productions of Late Antique and Medieval age. They usually contained texts from Holy Writings written with golden or silver inks on parchment dyed in a purple hue. According to the tradition, the colour of parchment was obtained by the well renowned Tyrian purple dye. From the material point of view, however, very little is known about the compounds actually used in the manufacture of these manuscripts. Presently, the information available is limited to the ancient art treatises, with very few diagnostic evidences supporting them and, moreover, none confirming the presence of Tyrian purple. It is more than apparent, then, the need to have at disposal larger and more complete information at the concern, in order to verify what came to us from the literary tradition only. In this study, preliminary results are presented from non-invasive investigation on a VI century purple codex, the so-called CodexBrixianus, held in the Biblioteca Civica Queriniana at Brescia (Italy). Analyses were carried out with XRF spectrometry, UV-visible diffuse reflectance spectrophotometry, molecular spectrofluorimetry and optical microscopy. The results suggest the hypothesis that Tyrian purple had been used as a minor component mixed with other less precious dyes such as folium or orchil.

  11. Characteristics and functional properties of purple corn (Zea mays L. var. subnigroviolaceo

    Directory of Open Access Journals (Sweden)

    Jhoseline Guillén-Sánchez

    2014-09-01

    Full Text Available Zea Mays L. variety purple (purple corn is a plant native of America, which has the episperm seeds (grains and the cobs (cob in purple, which gives special characteristics to the pigments that have (between 1.5% and 6.0%, called anthocyanins, which belong to the group of flavonoids. Due to its high content of anthocyanins (cianin C3G-3-glucose as its main color and phenolic compounds act as powerful natural antioxidant and anticancer, Further having functional properties due to these bioactive compounds. The purple corn also provides significant amounts of starch, about 80% (complex carbohydrate, 10% of sugars provide sweetness, up to 11% protein, up to 2% minerals and B vitamins and ascorbic acid, concentrated in endosperm (grain free envelope. Also the nutritional value, the purple corn has a rich composition of phytochemicals, which have beneficial effects on our body, such as neutralize free radicals and act as antimutagenic. His review paper aimed to collect information on the studies undertaken to purple corn as an alternative to artificial food dyes and health benefits when included in the diet. Benefits such as cardiovascular diseases (hypertension, lowering cholesterol, fighting diabetes, being the most remarkable antioxidant action (wrinkle.

  12. Morphological characteristic of purple long yard bean cultivars and their tolerance to drought stress

    Directory of Open Access Journals (Sweden)

    M W Lestari

    2015-01-01

    Full Text Available The cultivation of purple long yard bean which tolerance to drought stress and have high productivity can improve farming in arid area. The purpose of this study was to evaluate the mechanism of the tolerance purple long yard beans to drought stress based on morphologic characters, to get the hypothesis method of tolerance and to obtain tolerance cultivars to the drought stress. Eight cultivars of purple long yard beans, i.e. UBPHU1-41, UBPHU1-130, UBPU3-153, UBPU1-202, UBPU2-222, UBPU1-365, Brawijaya 4 and Bagong 2, were tested in two environmental conditions, 100% field capacity and 50% field capacity. The results showed that drought stress in purple long yard bean affected all morphological characters observed, except for root length and flowering time. Estimation of tolerance to drought stress using the Principles Component Analysis (PCA showed that the shoot fresh weight could be an indicator of purple pod bean tolerance to drought stress. However, the test using Stress Susceptibility Index (SSI was not able to classify the purple long yard bean tolerance to drought stress. The results of analysis using PCA followed by discriminant analysis and clustering dendrogram showed that the UBPU1-41, UBPU1-130, UBPU2-222, UBPU1-365, UB4 and Bagong 2 cultivars were medium cultivars that are tolerant to drought stress. Therefore, they can be planted in semiarid regions.

  13. Enhanced practical photosynthetic CO2 mitigation

    Science.gov (United States)

    Bayless, David J.; Vis-Chiasson, Morgan L.; Kremer, Gregory G.

    2003-12-23

    This process is unique in photosynthetic carbon sequestration. An on-site biological sequestration system directly decreases the concentration of carbon-containing compounds in the emissions of fossil generation units. In this process, photosynthetic microbes are attached to a growth surface arranged in a containment chamber that is lit by solar photons. A harvesting system ensures maximum organism growth and rate of CO.sub.2 uptake. Soluble carbon and nitrogen concentrations delivered to the cyanobacteria are enhanced, further increasing growth rate and carbon utilization.

  14. 紫薯南瓜凝固型酸奶发酵工艺研究%Research on Fermentation Technology of Purple Sweet Potato and Pumpkin Yoghourt

    Institute of Scientific and Technical Information of China (English)

    吴海燕; 邵元健; 李文婷

    2015-01-01

    Using purple sweet potato, pumpkin and milk as raw material, Lactic acid bacteria as leavening agents, the fermentation conditions of lactic acid fermented yoghourt were studied. The orthogonal experiments of L16(35) results showed that the optimize fermentation conditions were:the proportion of slurry and milk was 1 : 5 (g/mL),with the addition of sucrose 9 %, inoculums 0.7 %,fermentation time 5 hours, fermentation temperature 42 ℃. Under these conditions, the purple sweet potato and pumpkin yoghourt took on well-distributed quality, smooth, flour and sweet delicious taste with purple sweet potato and pumpkin fragrance, full-bodied scent of yoghourt coming from lactic fermentation. Both physiochemical indexes and microbial indexes complied with national standards.%以紫薯、南瓜、牛奶为主要原料,利用乳酸菌进行发酵,得到一种风味酸奶.通过L 16(3 5)正交试验优化发酵工艺条件,最佳发酵条件为:紫薯---南瓜浆与牛乳的比例为1:5(g/mL),蔗糖添加量为9%,菌种接种量为0.7%,发酵时间为5 h,发酵温度42℃.在该条件下制成酸奶质地均匀,口感细腻,酸甜可口,具有紫薯、南瓜的香味和浓郁的乳酸菌发酵酸奶香味,理化指标和微生物指标均符合国家标准.

  15. Investigation of structural change of purple membrane in storage by transmission electron microscope and atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The structural change of purple membrane during storage has been investigated by means of transmission electron microscope and atomic force microscope. It is found that many liposomes have spontaneously evolved from the purple membrane sheets isolated three years ago. The membrane proteins on the liposomes, bacteriorhodopsin, are still presented as trimers in 2-D hexagonal structure, which is the same as that in natural cell membrane. However, the cytoplasmic surface of purple membrane faced outside on the liposomes.

  16. Engineering analysis of potential photosynthetic bacterial hydrogen-production systems

    Science.gov (United States)

    Herlevich, A.; Karpuk, M. E.

    1982-06-01

    Photosynthetic bacteria (PSB) are capable of generating hydrogen from organics in effluents from food processing, pulp and paper, and chemical and pharmaceutical industries. Hydrogen evolution takes place under light in the absence of air. The rate of hydrogen production is expected to range between 300 to 600 scf of hydrogen per 1000 galloons of waste stream treated per hour. This hydrogen production system has been demonstrated at a bench-scale level and is ready for engineering development. A conceptual design for a PSB hydrogen production system is described. The system is expected to be sited adjacent to a waste stream source which will be pretreated by fermentation and pH adjustment, innoculated with bacteria, and then passed into the reactor. The reactor effluent can either be discharged into a rapid infiltration system, an irrigation ditch, and/or recycled back into the reactor. Several potential reactor designs have been developed, analyzed, and costed. A large covered pond appears to be the most economical design approach.

  17. Reproducing stone monument photosynthetic-based colonization under laboratory conditions.

    Science.gov (United States)

    Miller, Ana Zélia; Laiz, Leonila; Gonzalez, Juan Miguel; Dionísio, Amélia; Macedo, Maria Filomena; Saiz-Jimenez, Cesareo

    2008-11-01

    In order to understand the biodeterioration process occurring on stone monuments, we analyzed the microbial communities involved in these processes and studied their ability to colonize stones under controlled laboratory experiments. In this study, a natural green biofilm from a limestone monument was cultivated, inoculated on stone probes of the same lithotype and incubated in a laboratory chamber. This incubation system, which exposes stone samples to intermittently sprinkling water, allowed the development of photosynthetic biofilms similar to those occurring on stone monuments. Denaturing gradient gel electrophoresis (DGGE) analysis was used to evaluate the major microbial components of the laboratory biofilms. Cyanobacteria, green microalgae, bacteria and fungi were identified by DNA-based molecular analysis targeting the 16S and 18S ribosomal RNA genes. The natural green biofilm was mainly composed by the Chlorophyta Chlorella, Stichococcus, and Trebouxia, and by Cyanobacteria belonging to the genera Leptolyngbya and Pleurocapsa. A number of bacteria belonging to Alphaproteobacteria, Bacteroidetes and Verrucomicrobia were identified, as well as fungi from the Ascomycota. The laboratory colonization experiment on stone probes showed a colonization pattern similar to that occurring on stone monuments. The methodology described in this paper allowed to reproduce a colonization equivalent to the natural biodeteriorating process.

  18. Interactions between colloidal silver and photosynthetic pigments located in cyanobacteria fragments and in solution.

    Science.gov (United States)

    Siejak, Przemysław; Frackowiak, Danuta

    2007-09-25

    Changes in the yield of the fluorescence emitted by pigments of photosynthetic organisms could be used for the establishment of the presence of some toxic substances. The presence of colloidal metals can be indicated by enhancement of pigments' emission as a result of plasmons generation. The spectra of the pigments of cyanobacterium Synechocystis located in the bacterium fragments and in solutions with and without colloidal silver additions have been measured. The quantum yield of the pigments' fluorescence in solution has been observed to increase at some wavelength of excitation, while the fluorescence of the pigments in the bacteria fragments has been only quenched as a consequence of interactions with colloidal silver particles. Close contact between pigment molecules located in bacteria fragments and silver particles is probably not possible. We plan in future to investigate the influence of other, more typical metal pollutants of water, using similar spectral methods and several other photosynthetic bacteria pigments, in solution, in cell fragments and in the whole bacteria organisms.

  19. Rapid Redox Signal Transmission by “Cable Bacteria” beneath a Photosynthetic Biofilm

    Science.gov (United States)

    Meysman, F. J. R.

    2014-01-01

    Recently, long filamentous bacteria, belonging to the family Desulfobulbaceae, were shown to induce electrical currents over long distances in the surface layer of marine sediments. These “cable bacteria” are capable of harvesting electrons from free sulfide in deeper sediment horizons and transferring these electrons along their longitudinal axes to oxygen present near the sediment-water interface. In the present work, we investigated the relationship between cable bacteria and a photosynthetic algal biofilm. In a first experiment, we investigated sediment that hosted both cable bacteria and a photosynthetic biofilm and tested the effect of an imposed diel light-dark cycle by continuously monitoring sulfide at depth. Changes in photosynthesis at the sediment surface had an immediate and repeatable effect on sulfide concentrations at depth, indicating that cable bacteria can rapidly transmit a geochemical effect to centimeters of depth in response to changing conditions at the sediment surface. We also observed a secondary response of the free sulfide at depth manifest on the time scale of hours, suggesting that cable bacteria adjust to a moving oxygen front with a regulatory or a behavioral response, such as motility. Finally, we show that on the time scale of days, the presence of an oxygenic biofilm results in a deeper and more acidic suboxic zone, indicating that a greater oxygen supply can enable cable bacteria to harvest a greater quantity of electrons from marine sediments. Rapid acclimation strategies and highly efficient electron harvesting are likely key advantages of cable bacteria, enabling their success in high sulfide generating coastal sediments. PMID:25416774

  20. Growth and yield of maize in purple nutsedge interference

    Directory of Open Access Journals (Sweden)

    Daniel Valadão Silva

    2015-10-01

    Full Text Available This research aimed evaluates the influence of purple nutsedge (Cyperus rotundus on the agronomic performance of maize. We conducted a field experiment at Viçosa, MG, in completely randomized design experimental with three replications. The treatments consisted of the interaction of maize with nine nutsedge densities (0, 10, 30, 50, 90, 110, 130, 160 and 260 plants m-2. In the flowering culture was made the measurement of plant height, the insertion of the corn ears and the total dry matter of corn plants. At harvest were determined ear weight, grain yield and 100-grain weight adjusted to 13% moisture. Higher density of nutsedge increased plant height and the insertion of the first corn ear. We also observed a reduction in total dry matter accumulation, ear weight, 100-grain weight and grain yield in all densities evaluate. Nutsedge control, even at low densities is necessary because the presence of this plant promotes negative effect on growth and development of corn with a direct consequences on crop productivity.

  1. Identification and quantification of anthocyanins in transgenic purple tomato.

    Science.gov (United States)

    Su, Xiaoyu; Xu, Jianteng; Rhodes, Davina; Shen, Yanting; Song, Weixing; Katz, Benjamin; Tomich, John; Wang, Weiqun

    2016-07-01

    Anthocyanins are natural pigments derived from the phenylpropanoid pathway. Most tomatoes produce little anthocyanins, but the transgenic purple tomato biosynthesizes a high level of anthocyanins due to expression of two transcription factors (Del and Ros1). This study was to identify and quantify anthocyanins in this transgenic tomato line. Seven anthocyanins, including two new anthocyanins [malvidin-3-(p-coumaroyl)-rutinoside-5-glucoside and malvidin-3-(feruloyl)-rutinoside-5-glucoside], were identified by LC-MS/MS. Petunidin-3-(trans-coumaroyl)-rutinoside-5-glucoside and delphinidin-3-(trans-coumaroyl)-rutinoside-5-glucoside were the most abundant anthocyanins, making up 86% of the total anthocyanins. Compared to undetectable anthocyanins in the wild type, the contents of anthocyanins in the whole fruit, peel, and flesh of the Del/Ros1-transgenic tomato were 5.2±0.5, 5.1±0.5, and 5.8±0.3g/kg dry matter, respectively. Anthocyanins were undetectable in the seeds of both wide-type and transgenic tomato lines. Such novel and high levels of anthocyanins obtained in this transgenic tomato may provide unique functional products with potential health benefits.

  2. SYMMETRY AS CONCEPTUAL METAPHOR IN WALKER'S THE COLOR PURPLE

    Directory of Open Access Journals (Sweden)

    Elena Tapia

    2003-05-01

    Full Text Available The author analyzes three types of the conceptual metaphor of embodied symmetry in Alice Walker's novel, The color purple (1982. These metaphorical projections, perceived as equilibrium and its breakage in abstract phenomena, enable readers to reexamine issues of race, non-traditional families, and gender roles. The dis/equilibrium emerges in the novel's epistolary structure. Biological equilibrium breaks in incidents of rape and incest. Walker creates characters in the novel through default-concept opposites of black/white, submissive/dominant, male/female and others. These contraries foreground issues of race and gender. The novel's asymmetries engage readers, leading them to rethink individual character histories and motives. The removal of objects (e.g., rape, mothers deprived of children suggests conceptual asymmetry and alerts readers to parallel themes of sexual and racial oppression. Subjugation sometimes subtle, sometimes blatant- manifests in simple oppositions. In epistemological terms, readers seek causal explanations for the asymmetries of the narrative, interpreting each to recover its history.

  3. Red, purple and pink: the colors of diffusion on pinterest.

    Directory of Open Access Journals (Sweden)

    Saeideh Bakhshi

    Full Text Available Many lab studies have shown that colors can evoke powerful emotions and impact human behavior. Might these phenomena drive how we act online? A key research challenge for image-sharing communities is uncovering the mechanisms by which content spreads through the community. In this paper, we investigate whether there is link between color and diffusion. Drawing on a corpus of one million images crawled from Pinterest, we find that color significantly impacts the diffusion of images and adoption of content on image sharing communities such as Pinterest, even after partially controlling for network structure and activity. Specifically, Red, Purple and pink seem to promote diffusion, while Green, Blue, Black and Yellow suppress it. To our knowledge, our study is the first to investigate how colors relate to online user behavior. In addition to contributing to the research conversation surrounding diffusion, these findings suggest future work using sophisticated computer vision techniques. We conclude with a discussion on the theoretical, practical and design implications suggested by this work-e.g. design of engaging image filters.

  4. Redox properties of an engineered purple Cu(A) azurin.

    Science.gov (United States)

    Sun, Dapeng; Wang, Xiaotang; Davidson, Victor L

    2002-08-01

    Purple Cu(A) centers are a class of binuclear, mixed-valence copper complexes found in cytochrome c oxidase and nitrous oxide reductase. An engineered Cu(A) protein was formed by replacing a portion of the amino acid sequence that contains three of the ligands to the native type I copper center of Pseudomonas aeruginosa azurin with the corresponding portion of sequence from the Cu(A) center of cytochrome c oxidase from Paracoccus denitrificans [Proc. Natl. Acad. Sci. USA 93 (1996) 461]. Oxidation-reduction midpoint potential (E(m)) values of the Cu(A) azurin of +399+/-10 and +380+/-2mV, respectively, were determined by cyclic voltammetry and spectrochemical titration. An n value of one was obtained, indicating that the redox reaction is cycling between the mixed valence and the fully reduced states. Whereas the E(m) value of native azurin is pH dependent, the E(m) value of Cu(A) azurin is not, as expected for the Cu(A) center. Similarities and differences in the redox properties are discussed in terms of the known crystal structures of Cu(A) centers in cytochrome c oxidase and Cu(A) azurin.

  5. Purple Salt and Tiny Drops of Water in Meteorites

    Science.gov (United States)

    Taylor, G. J.

    1999-12-01

    Some meteorites, especially those called carbonaceous chondrites, have been greatly affected by reaction with water on the asteroids in which they formed. These reactions, which took place during the first 10 million years of the Solar System's history, formed assorted water-bearing minerals, but nobody has found any of the water that caused the alteration. Nobody, that is, until now. Michael Zolensky and team of scientists from the Johnson Space Center in Houston and Virginia Tech (Blacksburg, Virginia) discovered strikingly purple sodium chloride (table salt) crystals in two meteorites. The salt contains tiny droplets of salt water (with some other elements dissolved in it). The salt is as old as the Solar System, so the water trapped inside the salt is also ancient. It might give us clues to the nature of the water that so pervasively altered carbonaceous chondrites and formed oceans on Europa and perhaps other icy satellites. However, how the salt got into the two meteorites and how it trapped the water remains a mystery - at least for now.

  6. Tillage Effect on Organic Carbon in a Purple Paddy Soil

    Institute of Scientific and Technical Information of China (English)

    HUANG Xue-Xia; GAO Ming; WEI Chao-Fu; XIE De-Ti; PAN Gen-Xing

    2006-01-01

    The distribution and storage of soil organic carbon (SOC) based on a long-term experiment with various tillage systems were studied in a paddy soil derived from purple soil in Chongqing, China. Organic carbon storage in the 0-20and 0-40 cm soil layers under different tillage systems were in an order: ridge tillage with rice-rape rotation (RT-rr)> conventional tillage with rice only (CT-r) > ridge tillage with rice only (RT-r) > conventional tillage with rice-rape rotation (CT-rr). The RT-rr system had significantly higher levels of soil organic carbon in the 0-40 cm topsoil, while the proportion of the total remaining organic carbon in the total soil organic carbon in the 0-10 cm layer was greatest in the RT-rr system. This was the reason why the RT-rr system enhanced soil organic carbon storage. These showed that tillage system type was crucial for carbon storage. Carbon levels in soil humus and crop-yield results showed that the RT-rr system enhanced soil fertility and crop productivity. Adoption of this tillage system would be beneficial both for environmental protection and economic development.

  7. Total Monomeric Anthocyanin and Total Flavonoid Content of Processed Purple

    Directory of Open Access Journals (Sweden)

    Potato Florentina Damşa

    2016-01-01

    Full Text Available It is well known that processing change physical and chemical composition of foods, thus affecting the content in bioactive substances. Potatoes are almost always consumed after processing (baked, fried or boiled making it critical to understand the effect of such processing techniques on the containing in bioactive compounds. In order to determine the influence of processing on the content of anthocyanin pigments and flavonoids was achieved the extraction of these compounds from boiled and baked purple potato tuber (Albastru-Violet de Galanesti variety. Also, in order to obtain the maximum amount of anthocyanin pigments and flavonoids from processed potatoes was applied ultrasonic extraction (20 kHz and was performed the mathematical modeling (central composite design using SigmaXL software. The total anthocyanins content were determined spectrophotometrically by the pH differential method and the total flavonoids content were determine colorimetric by AlCl3 method. This study proves that the potato processing decreases the content of anthocyanin pigments and flavonoids.

  8. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    , Thiomargarita namibiensis, with a diameter of 750 mum. All bacteria, including those that swim around in the environment, obtain their food molecules by molecular diffusion. Only the fastest and largest swimmers known, Thiovulum majus, are able to significantly increase their food supply by motility......, the 80 x 600 mum large Epulopiscium sp. from the gut of tropical fish, are presumably living in a very nutrient-rich medium. Many large bacteria contain numerous inclusions in the cells that reduce the volume of active cytoplasm. The most striking examples of competitive advantage from large cell size...

  9. 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

  10. 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 prote

  11. 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 prote

  12. Nonlinear optical absorption of photosynthetic pigment molecules in leaves.

    Science.gov (United States)

    Ye, Zi-Piao

    2012-04-01

    A mathematical formulation of the relationship between optical absorption coefficient of photosynthetic pigment molecules and light intensity was developed. It showed that physical parameters of photosynthetic pigment molecule (i.e., light absorption cross-section of photosynthetic pigment molecule, its average lifetime in the excited state, total photosynthetic pigment molecules, the statistical weight, or degeneracy of energy level of photosynthetic pigment molecules in the ground state and in the excited state) influenced on both the light absorption coefficient and effective light absorption cross-section of photosynthetic pigment molecules. Moreover, it also showed that both the light absorption coefficient and effective light absorption cross-section of photosynthetic pigment molecules were not constant, they decreased nonlinearly with light intensity increasing. The occupation numbers of photosynthetic pigment molecules in the excited states increased nonlinearly with light intensity increasing.

  13. Study on the Technology of Purple Yam and Purple Sweet Potato Noodles%紫淮山紫薯营养面条的研制

    Institute of Scientific and Technical Information of China (English)

    李冬梅; 杨君; 周妮妮; 张伟惠; 赖来展

    2014-01-01

    Powder was made by vacuum drying fresh purple yam.With purple yam powder,purple sweet potato powder and flour as the main raw material a new nutritional and heathy noodles was made.Through the combination of single-factor test and orthogonal test was used to determine noodle break rate,loss rate,and sensory evaluation value,the best formula of noodles was concluded.The results showed that the optimum compound for purple chinese yam and purple sweet potato noodle is flour amout 100 g,salt 1.5 g,purple yam powder 10%, purple sweet potato powder 5%, earrageenin 0.5%.Under the obove congditiongs, the noole break rate is 0 and the noodle loss rate is 8.25%,the product has good sensory properties,high nutrional value ,strong health fountion,it would have a broad market prospect.%用新鲜紫淮山通过真空干燥制得紫淮山粉。以紫淮山粉、紫薯粉、面粉为主要原料,研制成新型营养保健面条。采用单因素和正交试验相结合的方法测定面条的断条率、烹煮损失率和感官评价值,确定紫淮山紫薯面条的最佳加工工艺配方。结果表明:紫淮山紫薯面条的最佳配方为高筋面粉量100 g,食盐1.5 g,添加紫淮山粉10%,紫薯粉5%,卡拉胶0.50%。在此工艺条件下,面条断条率为0、烹煮损失率为8.25%,产品感官性状良好、营养价值高、保健作用强,具有广阔的市场前景。

  14. Effect of a light-induced pH gradient on purple-to-blue and purple-to-red transitions of bacteriorhodopsin

    Energy Technology Data Exchange (ETDEWEB)

    Nasuda-Kouyama, A.; Fukuda, K.; Iio, T.; Kouyama, T. (Institute of Physical and Chemical Research, Saitama (Japan))

    1990-07-24

    Bacteriorhodopsin-containing vesicles that were able to alkalize the extravesicular medium by greater than 1.5 pH units under illumination, i.e., inside-out vesicles, were reconstituted by reverse-phase evaporation with Halobacterium halobium polar lipids or exogenous phospholipids. Acid titration of a dark-adapted sample was accompanied by a color change from purple to blue (pKa = 2.5-4.5 in 0.15 M K2SO4), and alkali titration resulted in the formation of a red species absorbing maximally at 480 nm (pKa = 7 to greater than 9), the pKa values and the extents of these color changes being dependent on the nature of lipid. When a vesicle suspension at neutral or weakly acidic pH was irradiated by continuous light so that a large pH gradient was generated across the membrane, either a purple-to-blue or a purple-to-red transition took place. The light-induced purple-to-red transition was significant in an unbuffered vesicle suspension and correlated with the pH change in the extravesicular medium. The result suggests that the purple-to-red transition is driven from the extravesicular side, i.e., from the C-terminal membrane surface. In the presence of buffer molecules outside, the dominant color change induced in the light was the purple-to-blue transition, which seemed to be due to a large decrease in the intravesicular pH. But an apparently inconsistent result was obtained when the extravesicular medium was acidified by a HCl pulse, which was accompanied by a rapid color change to blue. We arrived at the following explanation: The two bR isomers, one containing all-trans-retinal and the other 13-cis-retinal, respond differently to pH changes in the extravesicular and the intravesicular medium. In this relation, full light adaptation was not achieved when the light-induced purple-to-blue transition was significant.

  15. Effect of a light-induced pH gradient on purple-to-blue and purple-to-red transitions of bacteriorhodopsin.

    Science.gov (United States)

    Nasuda-Kouyama, A; Fukuda, K; Iio, T; Kouyama, T

    1990-07-24

    Bacteriorhodopsin-containing vesicles that were able to alkalize the extravesicular medium by greater than 1.5 pH units under illumination, i.e., inside-out vesicles, were reconstituted by reverse-phase evaporation with Halobacterium halobium polar lipids or exogenous phospholipids. Acid titration of a dark-adapted sample was accompanied by a color change from purple to blue (pKa = 2.5-4.5 in 0.15 M K2SO4), and alkali titration resulted in the formation of a red species absorbing maximally at 480 nm (pKa = 7 to greater than 9), the pKa values and the extents of these color changes being dependent on the nature of lipid. When a vesicle suspension at neutral or weakly acidic pH was irradiated by continuous light so that a large pH gradient was generated across the membrane, either a purple-to-blue or a purple-to-red transition took place. The light-induced purple-to-red transition was significant in an unbuffered vesicle suspension and correlated with the pH change in the extravesicular medium. The result suggests that the purple-to-red transition is driven from the extravesicular side, i.e., from the C-terminal membrane surface. In the presence of buffer molecules outside, the dominant color change induced in the light was the purple-to-blue transition, which seemed to be due to a large decrease in the intravesicular pH. But an apparently inconsistent result was obtained when the extravesicular medium was acidified by a HCl pulse, which was accompanied by a rapid color change to blue. We arrived at the following explanation: The two bR isomers, one containing all-trans-retinal and the other 13-cis-retinal, respond differently to pH changes in the extravesicular and the intravesicular medium. In this relation, full light adaptation was not achieved when the light-induced purple-to-blue transition was significant; i.e., only the 13-cis isomer is likely to respond to a pH change at the N-terminal membrane surface.

  16. Study of the Photosynthetic Characteristics of Four Kinds of Colorful Plants%四种彩叶树种光合特性研究

    Institute of Scientific and Technical Information of China (English)

    刘嘉君; 王志刚; 刘炳响; 任志彬

    2011-01-01

    [目的]比较4种彩叶树种的光合特性及叶绿素特征,以期为彩叶树种的合理配置提供理论依据.[方法]在自然条件下,采用英国生产的LCI便携式植物光合测定仪测定自然生长的4种彩叶植物的光合特征,采用分光光度法测定彩叶植物叶绿素及花色素苷含量.对紫叶李(Prunus cerasifera f.atropurpurea)、紫叶矮樱(Prunm×cistena)、金叶女贞(Ligustrum×vicaryi)和金叶连翘(Forsythia suspensa(Thunb.)Vahl)4种彩叶树种光合特性日变化及植物色素含量进行研究.[结果]4种彩叶树种的光合作用能力强弱顺序为:紫叶李>紫叶矮樱>金叶女贞>金叶连翘,2种紫叶树种的净光和速率、蒸腾速率和气孔导度均高于金叶树种,而水分利用效率则相反;紫叶李和紫叶矮樱的叶绿素含量明显高于金叶女贞和金叶连翘.[结论]金叶树种的节水能力强于紫叶树种,而紫叶树种叶片的光能吸收和耐阴性强于金叶树种.%[ Objective ] The study aims to compare photosynthetic characteristics and the contents of pigments in the four kinds of colorful plants, in order to provide basis for the rational allocation of colored tree species. [ Method] Diurnal variation of photosynthetic characteristics and content of plant pigments of Prunus cerasifera f. atropurpurea, Prunus x cistena, Ligustrum x vicaryi and Forsythia suspensa( Thunb. ) Vahlcolorful plants are studied under natural conditions, by using LCI portable photosynthesis system , and the contents of pigments by using spectrophotometry. [ Result] Results show that the Photosynthetic capacity of four colorful plants is that Prunus cerasifera? f. atropurpurea >Prunus x cistena > Ligustrum x vicaryi > Forsythia suspensa( Thunb. ) Vahl, and net photosynthetic rate, transpiration rate and stomatal conductance of two kinds of plants with purple leaves are higher than that of two kinds of plants with golden leaves, but the moisture utilization rate of two kinds of

  17. Longitudinal photosynthetic gradient in crust lichens' thalli.

    Science.gov (United States)

    Wu, Li; Zhang, Gaoke; Lan, Shubin; Zhang, Delu; Hu, Chunxiang

    2014-05-01

    In order to evaluate the self-shading protection for inner photobionts, the photosynthetic activities of three crust lichens were detected using Microscope-Imaging-PAM. The false color images showed that longitudinal photosynthetic gradient was found in both the green algal lichen Placidium sp. and the cyanolichen Peltula sp. In longitudinal direction, all the four chlorophyll fluorescence parameters Fv/Fm, Yield, qP, and rETR gradually decreased with depth in the thalli of both of these two lichens. In Placidium sp., qN values decreased with depth, whereas an opposite trend was found in Peltula sp. However, no such photosynthetic heterogeneity was found in the thalli of Collema sp. in longitudinal direction. Microscope observation showed that photobiont cells are compactly arranged in Placidium sp. and Peltula sp. while loosely distributed in Collema sp. It was considered that the longitudinal photosynthetic heterogeneity was ascribed to the result of gradual decrease of incidence caused by the compact arrangement of photobiont cells in the thalli. The results indicate a good protection from the self-shading for the inner photobionts against high radiation in crust lichens.

  18. Natural strategies for photosynthetic light harvesting

    NARCIS (Netherlands)

    Croce, R.; Amerongen, van H.

    2014-01-01

    Photosynthetic organisms are crucial for life on Earth as they provide food and oxygen and are at the basis of most energy resources. They have a large variety of light-harvesting strategies that allow them to live nearly everywhere where sunlight can penetrate. They have adapted their pigmentation

  19. Photosynthetic antenna engineering to improve crop yields.

    Science.gov (United States)

    Kirst, Henning; Gabilly, Stéphane T; Niyogi, Krishna K; Lemaux, Peggy G; Melis, Anastasios

    2017-05-01

    Evidence shows that decreasing the light-harvesting antenna size of the photosystems in tobacco helps to increase the photosynthetic productivity and plant canopy biomass accumulation under high-density cultivation conditions. Decreasing, or truncating, the chlorophyll antenna size of the photosystems can theoretically improve photosynthetic solar energy conversion efficiency and productivity in mass cultures of algae or plants by up to threefold. A Truncated Light-harvesting chlorophyll Antenna size (TLA), in all classes of photosynthetic organisms, would help to alleviate excess absorption of sunlight and the ensuing wasteful non-photochemical dissipation of excitation energy. Thus, solar-to-biomass energy conversion efficiency and photosynthetic productivity in high-density cultures can be increased. Applicability of the TLA concept was previously shown in green microalgae and cyanobacteria, but it has not yet been demonstrated in crop plants. In this work, the TLA concept was applied in high-density tobacco canopies. The work showed a 25% improvement in stem and leaf biomass accumulation for the TLA tobacco canopies over that measured with their wild-type counterparts grown under the same ambient conditions. Distinct canopy appearance differences are described between the TLA and wild type tobacco plants. Findings are discussed in terms of concept application to crop plants, leading to significant improvements in agronomy, agricultural productivity, and application of photosynthesis for the generation of commodity products in crop leaves.

  20. Mechanism of photoprotection in photosynthetic proteins

    OpenAIRE

    TRSKOVÁ, Eliška

    2015-01-01

    Nonphotochemical quenching is an important protective mechanism of photosynthetic proteins against excessive irradiation. In this work, isolation of native light harvesting antennae from alga Chromera velia was optimized using methods of sucrose density centrifugation, isoelectric focusing, ion exchange chromatography and gel electrophoresis. Moreover, the ability of light harvesting antennae to trigger nonphotochemical quenching was studied in vivo and in vitro.

  1. Comparison of loess and purple rill erosions measured with volume replacement method

    Science.gov (United States)

    Chen, Xiao-yan; Huang, Yu-han; Zhao, Yu; Mo, Bin; Mi, Hong-xing

    2015-11-01

    Rills are commonly found on sloping farm fields in both the loess and the purple soil regions of China. A comparative study on rill erosion between the two soils is important to increase research knowledge and exchange application experiences. Rill erosion processes of loess and purple soils were determined through laboratory experiments with the volume replacement method. Water was used to refill the eroded rill segments to compute eroded volume before sediment concentration distribution along the rill was computed using the soil bulk density, flow rate, and water flow duration. The experimental loess soil materials were from the Loess Plateau and purple soil from the southwestern part of China, Chongqing City. A laboratory experimental platform was used to construct flumes to simulate rills with 12.0 m length, 0.1 m width, and 0.3 m depth. Soil materials were filled into the flumes at a bulk density of 1.2 g cm-3 to a depth of 20 cm to form rills for experiments on five slope gradients (5°, 10°, 15°, 20°, and 25°) and three flow rates (2, 4, and 8 L/min). After each experimental run under the given slope gradient and flow rate, the rill segments from the upper slope between 0-0.5, 0.5-1, 1-2, 2-3, …, 7-8, 8-10, and 10-12 m were lined with plastic sheets before be re-filled with water to determine sediment concentration after the eroded volumes was measured. Rill erosion differed between the two soils. As purple soil started to erode at a higher erosive force than loess soil, it possibly exhibits higher resistance to water erosion. The subsequent erosion process in the eroding purple rill was similar to that in the loess rill. However, the total erosion in the eroding loess rill was more than that in the eroding purple rill. The maximum sediment concentration transported by the eroding purple rills was significantly lower, approximately 55% of those transported by the loess rills under the same flow rate and slope gradient. Hence, less purple sediments can

  2. Was photosynthetic RuBisCO recruited by acquisitive evolution from RuBisCO-like proteins involved in sulfur metabolism?

    Science.gov (United States)

    Ashida, Hiroki; Danchin, Antoine; Yokota, Akiho

    2005-01-01

    Genome analyses have revealed that the genomes of non-photosynthetic bacteria including Bacillus subtilis code for proteins similar to the large subunit of RuBisCO (called RuBisCO-like protein (RLP)). This raises a fundamental question as to their functional relationship to photosynthetic RuBisCO. Recently, we identified the RLP of B. subtilis as the 2,3-diketo-5-methylthiopentyl-1-phosphate enolase in the methionine salvage pathway. In this mini-review, we suggest functional and evolutionary links between B. subtilis RLP and photosynthetic RuBisCO. Furthermore, we propose that photosynthetic RuBisCOs evolved from RLPs similar to that found in B. subtilis.

  3. 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.

  4. Stomatal behavior in fruits and leaves of the purple passion fruit (Passiflora edulis Sims and fruits and cladodes of the yellow pitaya [Hylocereus megalanthus (K. Schum. ex Vaupel Ralf Bauer

    Directory of Open Access Journals (Sweden)

    Camilo Sánchez

    2013-04-01

    Full Text Available Plants as C3 and CAM react photosynthetically different but both can grow in the same agroecological zone in the tropics. Therefore we studied the behavior of stomatal opening in fruits and leaves of the purple passion fruit and fruits and cladodes of the yellow pitaya was studied under natural growing conditions in Granada and Fusagasuga, Cundinamarca (Colombia. Imprints were made on the surface of leaves, fruits and cladodes using cosmetic enamel impressions. Three cycles were carried out, each cycle took 72 hours, obtaining three different samples every 3 hours; then the impressions were observed by microscope and the opened and closed stomata were counted in each species. In each sampling, data of solar radiation, temperature and relative humidity (RH were measured. The purple passion fruit had the typical behavior of a C3 plant in the leaves as well as the fruits, and a positive correlation between the stomatal aperture and radiation and temperature was found, along with a negative correlation between stomatal aperture and RH. The pitaya showed the typical behavior of a CAM plant with a negative correlation between the stomatal opening and radiation and temperature, as well as a positive correlation between stomatal opening and RH. Radiation, temperature and RH affected the stomatal opening in the fruits and cladodes. Stomatal densities differed greatly between the species and plant organs. In the purple passion fruit, 106.53 stomata per mm² leaf surface were found, but only 12.64 stomata per mm² fruit surface; whereas in the pitaya, 11.28 and 1.43 stomata per mm² were found on the cladodes and fruits, respectively

  5. Understory flora and community physiognomy of planted forests in the degraded purple soil ecosystem, South China

    Institute of Scientific and Technical Information of China (English)

    YUZhan-yuan; YUEYong-jie; GUOJian-fen; CHENGuang-shui; XIEJin-sheng; HEZong-ming; YANGYu-sheng

    2005-01-01

    The flora and community physiognomy of degraded plantation ecosystems on purple soil were investigated in Ninghua County of Fujian Province, China to understand the relationship between plant diversity and ecosystem processes.. Four different restoration communities (labeled as ecological restoration treatment I, II, Ill and IV) were selected by space-time replacement method according to the erosion intensity in degraded purple soil ecosystem. The results showed that there were totally 86 plant species belonging to 78 genera and 43 families in the degraded purple soil ecosystem. Of the 15 types of distribution area in spermatophyte genus, 12 types were found in the purple soil ecosystem. Along restoration gradient from low to high, plant growth type and life form spectra became abundant more and more, and the spermatophyte genera for each distribution area type and genera numbers for different foliage characters increased as well. It is concluded that the plant flora and physiognomy in ecological restoration process become more complex and diverse, indicating that the forest ecosystem on purple soil tends to be more stable.

  6. Chromatic acclimation and population dynamics of green sulfur bacteria grown with spectrally tailored light

    OpenAIRE

    Saikin, Semion K.; Yadana Khin; Joonsuk Huh; Moataz Hannout; Yaya Wang; Farrokh Zare; Alán Aspuru-Guzik; Joseph Kuo-Hsiang Tang

    2014-01-01

    Living organisms have to adjust to their surrounding in order to survive in stressful conditions. We study this mechanism in one of most primitive creatures - photosynthetic green sulfur bacteria. These bacteria absorb photons very efficiently using the chlorosome antenna complexes and perform photosynthesis in extreme low-light environments. How the chlorosomes in green sulfur bacteria are acclimated to the stressful light conditions, for instance, if the spectrum of light is not optimal for...

  7. Chromatic acclimation and population dynamics of green sulfur bacteria grown with spectrally tailored light

    OpenAIRE

    Saikin, Semion K.; Khin, Yadana; Huh, Joonsuk; Hannout, Moataz; Wang, Yaya; Zare, Farrokh; Aspuru-Guzik, Alán; Tang, Joseph Kuo-Hsiang

    2014-01-01

    Living organisms have to adjust to their surrounding in order to survive in stressful conditions. We study this mechanism in one of most primitive creatures – photosynthetic green sulfur bacteria. These bacteria absorb photons very efficiently using the chlorosome antenna complexes and perform photosynthesis in extreme low-light environments. How the chlorosomes in green sulfur bacteria are acclimated to the stressful light conditions, for instance, if the spectrum of light is not optimal for...

  8. Solid-state NMR applied to photosynthetic light-harvesting complexes.

    Science.gov (United States)

    Pandit, Anjali; de Groot, Huub J M

    2012-03-01

    This short review describes how solid-state NMR has provided a mechanistic and electronic picture of pigment-protein and pigment-pigment interactions in photosynthetic antenna complexes. NMR results on purple bacterial antenna complexes show how the packing of the protein and the pigments inside the light-harvesting oligomers induces mutual conformational stress. The protein scaffold produces deformation and electrostatic polarization of the BChl macrocycles and leads to a partial electronic charge transfer between the BChls and their coordinating histidines, which can tune the light-harvesting function. In chlorosome antennae assemblies, the NMR template structure reveals how the chromophores can direct their self-assembly into higher macrostructures which, in turn, tune the light-harvesting properties of the individual molecules by controlling their disorder, structural deformation, and electronic polarization without the need for a protein scaffold. These results pave the way for addressing the next challenge, which is to resolve the functional conformational dynamics of the lhc antennae of oxygenic species that allows them to switch between light-emitting and light-energy dissipating states.

  9. Screening for resistance to purple seed stain Cercospora kikuchii by seed inoculation technique

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, S.H.; Oh, J.H.

    1978-01-01

    An attempt was made to establish a mass-screening technique for resistance to purple seed stain disease in soybean. Seeds sterilized in 1 : 10,000 mercuric chloride for 1 minute and transferred to Petridishes containing 20ml water agar plus 50 ppM of the sodium salt of 2,4-D were inoculated by placing a small agar cube containing fungal mycelium on the seed coat of each seed. A positive correlation betweeen natural infection of purple seed stain and purple discoloration by seed inoculation technique was highly significant and by this technique, some native soybean collections and introduced varieties were tested for resistance to the disease. Most of the soybean varieties tested were susceptible except for the varieties Hill, Harosoy and Sac, resistant comparatively.

  10. Purple urine bag syndrome in end-stage chronic kidney disease

    Directory of Open Access Journals (Sweden)

    Guillermo Delgado

    2014-12-01

    Full Text Available Introduction: When faced with violet, purple or purplish-blue urine, clinicians should consider urinary tract infection in their differential diagnosis. Case report: A 60-year-old woman with end-stage kidney disease and non-adherence to renal replacement therapy was admitted to our hospital for placement of hemodialysis catheter. During her hospitalization she had purple urine, and purple urine bag syndrome (PUBS was diagnosed. She was effectively treated with antibiotics and her urine returned to a dark yellow color. Discussion: Although this condition is often easily treated, diagnosing PUBS in chronic renal patients probably means an increased serum concentration of indoxyl sulfate, metabolite that is involved in the progression of both CKD and cardiovascular disease. Conclusion: Hence, in the context of our renal patients, perhaps PUBS is not as benign as supposed.

  11. Efficient Dye-Sensitized Solar Cells Using Red Turnip and Purple Wild Sicilian Prickly Pear Fruits

    Directory of Open Access Journals (Sweden)

    Aldo Di Carlo

    2010-01-01

    Full Text Available Dye-sensitized solar cells (DSSCs were assembled by using the bougainvillea flowers, red turnip and the purple wild Sicilian prickly pear fruit juice extracts as natural sensitizers of TiO2 films. The yellow orange indicaxanthin and the red purple betacyanins are the main components in the cocktail of natural dyes obtained from these natural products. The best overall solar energy conversion efficiency of 1.7% was obtained, under AM 1.5 irradiation, with the red turnip extract, that showed a remarkable current density (Jsc = 9.5 mA/cm2 and a high IPCE value (65% at λ = 470 nm. Also the purple extract of the wild Sicilian prickly pear fruit showed interesting performances, with a Jsc of 9.4 mA/cm2, corresponding to a solar to electrical power conversion of 1.26%.

  12. Ambipolar organic field effect transistors and inverters with the natural material Tyrian Purple

    Directory of Open Access Journals (Sweden)

    Eric Daniel Głowacki

    2011-12-01

    Full Text Available Ambipolar organic semiconductors enable complementary-like circuits in organic electronics. Here we show promising electron and hole transport properties in the natural pigment Tyrian Purple (6,6’-dibromoindigo. X-ray diffraction of Tyrian Purple films reveals a highly-ordered structure with a single preferential orientation, attributed to intermolecular hydrogen bonding. This material, with a band gap of ∼1.8 eV, demonstrates high hole and electron mobilities of 0.22 cm2/V·s and 0.03 cm2/V·s in transistors, respectively; and air-stable operation. Inverters with gains of 250 in the first and third quadrant show the large potential of Tyrian Purple for the development of integrated organic electronic circuits.

  13. Enhanced rate of intramolecular electron transfer in an engineered purple CuA azurin

    DEFF Research Database (Denmark)

    Farver, O; Lu, Y; Ang, M C

    1999-01-01

    V for blue copper azurin). The reorganization energy of the CuA center is calculated to be 0.4 eV, which is only 50% of that found for the wild-type azurin. These results represent a direct comparison of electron transfer properties of the blue and purple CuA sites in the same protein framework and provide...... and CuA centers are placed in the same location in the protein while all other structural elements remain the same. Long-range electron transfer is induced between the disulfide radical anion, produced pulse radiolytically, and the oxidized binuclear CuA center in the purple azurin mutant. The rate...... support for the notion that the binuclear purple CuA center is a more efficient electron transfer agent than the blue single copper center because reactivity of the former involves a lower reorganization energy....

  14. Characteristics of Phosphorous Adsorption and Desorption by Organo-Mineral Colloidal Complexes of Purple Paddy Soils

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The kinetic characteristics of P adsorption and desorption by organo-mineral colloidal complexes (OMC)were studied using acid, calcareous and neutral purple paddy soils taken from Chongqing and Sichuan, China.The results showed that the P adsorption capacity of the organo-mineral colloidal complexes differed with the soil types, being higher for the acid and calcareous purple soils than for the neutral purple soils. Partial removal of the organic matter increased the adsorption capacity of the colloidal complexes. A very significant positive correlation was found between the amounts of P desorbed from OMC and the P saturation degrees.The P adsorption reaction was quick at the early stage and slowed later. The raise of temperature increased P adsorption capacity and P adsorption rate of the colloidal complexes. The adsorption processes could be described by the Elovich equation.

  15. Zonal Distribution of the Erosion-Landslide and Soil Micromorphological Features in Purple Hilly Region

    Institute of Scientific and Technical Information of China (English)

    HE Yurong; LIAO Chaolin; XU Pei; ZHANG Baohua

    2005-01-01

    In the purple hilly region, erosions and landslides are all serious, and it is of great scientific value and practical significance to study their formation mechanism and distribution features there.In this paper, soil micromorphological methods and techniques were used to study the erosion zonal distribution in the region. The results indicated: (1)According to erosion process, the spacial distribution zones of the erosions and landslides in the purple hilly region with different solums were divided into scouring erosion zone, transport-diffusion zone, rocks and soil turbulence zone and sediment-bury zone; (2)The soil micromorphologic taxonomic feature identifying different erosion-landslide zone were found by studying the soil micromorphology of erosive zone in purple hilly region; (3) As for the erosion-landslide formation in the region, besides the external factors, the internal factors were found more important and favorable for landslide formation through the studies on the mieormorphological features of slide soil.

  16. Expression Analysis of Dihydroflavonol 4-Reductase Genes Involved in Anthocyanin Biosynthesis in Purple Grains of Wheat

    Institute of Scientific and Technical Information of China (English)

    Mao-Sen LIU; Fang WANG; Yu-Xiu DONG; Xian-Sheng ZHANG

    2005-01-01

    The grain color of wheat (Triticum aestivum L.) is an important characteristic in crop production.Dihydroflavonol 4-reductase genes (DFR) encode the key enzyme dihydroflavonol 4-reductase, which is involved in the pigmentation of plant tissues. To investigate the molecular mechanism of anthocyanin deposition in grains of wheat, we determined the expression of the wheat DFR gene in purple grains of cultivar Heimai 76. The results showed that DFR transcripts were localized in the seed coat of purple grains rather than in the pericarp, whereas anthocyanins were accumulated in both tissues of purple grains,suggesting that anthocyanin deposition was mainly regulated at the transcriptional level. Overexpression of the TaDFR-A gene in Arabidopsis showed that TaDFR-A was responsible for the pigmentation of Arabidopsis plant tissues, indicating TaDFR-A gene has the same role in Arabidopsis.

  17. Solid-state NMR studies of bacteriorhodopsin and the purple membrane

    CERN Document Server

    Mason, A J

    2001-01-01

    proteins. This technique may prove particularly useful when studying large proteins that are difficult to orient where the MAS lineshapes will remain relatively unaffected in comparison with current static NMR methods. Finally the MAOSS method was extended to the study of the lipid components of the purple membrane and the feasibility of determining structural constraints from phospholipid headgroups was assessed. The potential of using sup 3 sup 1 P NMR to observe qualitative protein-lipid interactions in both the purple membrane and reconstituted membranes containing bovine rhodopsin was also demonstrated. Following the demonstration of a new MAS NMR method for resolving orientational constraints in uni-axially oriented biological membranes (Glaubitz and Watts, 1998), experiments were performed to realise the potential of the new method on large, oriented membrane proteins. Using bacteriorhodopsin in the purple membrane as a paradigm for large membrane proteins, the protein was specifically labelled with de...

  18. Effect of the Purple Corn Beverage “Chicha Morada” in Composite Resin during Dental Bleaching

    Science.gov (United States)

    Acuña, Eric Dario; Delgado-Cotrina, Leyla; Rumiche, Francisco Aurelio

    2016-01-01

    During dental bleaching the staining potential of the surface would increase. This study aims to evaluate the staining susceptibility of one bleached composite resin after the exposure to three different beverages: Peruvian purple corn based beverage (chicha morada), green tea, and distilled water. Thirty disk-shaped specimens of one nanofill composite resin were prepared. The specimens were then divided into six groups (n = 5): purple corn (P), purple corn + bleaching (PB), green tea (T), green tea + bleaching (TB), distilled water (W), and distilled water + bleaching (WB). In groups that received bleaching, two sessions of bleaching with 35% hydrogen peroxide were done. Following bleaching, specimens were exposed to each liquid thirty minutes daily. Color was measured with a digital spectrophotometer. For statistical analysis, color measurement differences between the obtained results were used: during bleaching, after bleaching, and during + after bleaching. Two-way ANOVA was used to compare the color changes in the resins of all groups (p 3.3). PMID:27034897

  19. 紫山药紫甘薯保健酸乳的开发研究%Research and Development on Purple Sweet Potato and Purple Yam Acidophilus Milk

    Institute of Scientific and Technical Information of China (English)

    孔庆新; 袁书林

    2012-01-01

    以紫山药、紫甘薯和牛乳为原料,研发出一种集营养与保健作用为一体的新型保健饮料——紫山药紫甘薯保健酸乳;对其生产过程中的护色、发酵原料配比和发酵工艺参数分别进行了正交试验筛选。结果表明:紫山药紫甘薯最佳护色条件为柠檬酸0.4%、维生素C1.3%、氯化钙f1.30%,护色时间2h;发酵原料最佳配比V(为紫山药原浆):V(紫甘薯原浆)=2:1、原料乳的添加量为25%、糖的添加量为4%;最佳发酵工艺参数为发酵时间7h、发酵温度43℃、接种量4%。%Purple yam, purple sweet potato and milk as raw materials, "Purple Sweet Potato and Purple Yam Acidophilus Milk"--a new type of healthy drink was developed. The craft of protecting color, the ratio of raw material and ferrtaentation process parameters were optimized by the orthogonal test. The results showed that the optimal protecting color conditions were citric acid 0.4%, vitamin C 1.3%, calcium chloride 0.30%, protect color time 2 h; the optimal ratio of raw material were purple yam juice : purple sweet potato=2 : 1, the raw milk 25%, sucrose 4%. The optimal fermentation process parameters were fermentation time 7 h, fermentation temperature 43℃, inoculation concentration 4%.

  20. Transcriptional activation of a MYB gene controls the tissue-specific anthocyanin accumulation in a purple cauliflower mutant

    Science.gov (United States)

    Flavonoids such as anthocyanins possess significant health benefits to humans and play important physiological roles in plants. An interesting Purple gene mutation in cauliflower confers an abnormal pattern of anthocyanin accumulation, giving intense purple color in very young leaves, curds, and see...

  1. First report of purple coneflower phyllody associated with a 16SrI-B phytoplasma in Maryland

    Science.gov (United States)

    Purple coneflower (Echinacea purpurea (L.) Moench) is a flowering perennial plant native to North America and widely grown as an ornamental flower. During the summers of 1994 and 2007, purple coneflower plants in Maryland sporadically exhibited symptoms resembling those caused by phytoplasma infect...

  2. Fermentation Technology for Purple Sweet Potato Juice Soybean Yoghurt%发酵型紫薯大豆酸奶的研制

    Institute of Scientific and Technical Information of China (English)

    王新惠; 白婷; 张崟; 王国燕; 李俊霞; 邓晓燕; 罗静; 张庆

    2015-01-01

    以紫薯和黄豆为主要原料,选用嗜热链球菌(Streptococcus thermophiles 6038)和德氏乳酸杆菌保加利亚亚种(Lactobacillus delbrueckii subsp.bulgaricus),以1∶1混合作为发酵剂进行发酵,以感官评价为参考指标,确定紫薯大豆酸奶工艺参数。结果表明,紫薯大豆酸奶最佳工艺参数为:紫薯浆添加量8%、蔗糖添加量9%、接种量3%、发酵温度38℃、发酵时间8 h。在此条件下发酵的紫薯大豆酸奶,色泽呈均匀香芋色,口感细腻,酸奶特殊香气及紫薯味浓郁,酸甜适中,可溶性固形物≥10%,蛋白质含量≥2.9%,pH 4.6,酸度59°T,菌落总数3.1×107 cfu/mL,乳酸菌数2.8×107 cfu/mL,未检测出大肠杆菌和致病菌,其质量达到GB19302-2010《食品安全国家标准发酵乳》对酸奶的指标要求。%A new fermentation technology for solidification fermented soy milk prepared with purple sweet potato juice was investigated. The purple potatoes and soy milk were considered as raw materials and the mixture of Streptococcus thermophiles 6038 and Lactobacillus delbrueckii subsp.bulgaricus (1 ∶ 1) was selected as culture starters for preparation new flavor soybean yoghurt. The sensory evaluation was used as the index and the optimal fermentation technology of purple sweet potato juice soybean yoghurt was determined. The results showed that the best purple sweet potato soybean yogurt fermentation process parameters were as purple sweet potato juice addition 8 %, sugar addition 9 %, inoculation 3 %, fermentation temperature 38 ℃ and fermentation time 8 h. The healthcare yoghurt obtained was featured by uniform color , nice texture and smooth taste. Furthermore, the results showed that the quality of soybean yoghurt was as soluble solids≥10%, protein content≥2.9%, pH 4.6, the acidity of 59 °T, total number of colonies 3.1×107 cfu/mL and number of lactic acid bacteria 2.8×107 cfu/mL without E.coli and pathogenic

  3. [Characteristics of Adsorption Leaching and Influencing Factors of Dimethyl Phthalate in Purple Soil].

    Science.gov (United States)

    Wang, Qiang; Song, Jiao-yan; Zeng, Wei; Wang, Fa

    2016-02-15

    The typical soil-purple soil in Three Gorges Reservoir was the tested soil, the characteristics of adsorption leaching of dimethyl phthalate (DMP) in contaminated water by the soil, and the influencing factors in the process were conducted using soil column leaching experiment. The results showed that the parabolic equation was the best equation describing adsorption kinetics of DMP by soils. The concentration of DMP in the leaching solution had significant effect on the adsorption amounts of DMP. With the increasing concentration of DMP in the leaching solution, the adsorption capacities of DMP by purple soil increased linearly. The ionic strength and pH in leaching solution had significant effects on adsorption of DMP. On the whole, increasing of the ionic strength restrained the adsorption. The adsorption amounts at pH 5.0-7.0 were more than those under other pH condition. The addition of exogenous organic matter (OM) in purple soil increased the adsorption amount of DMP by purple soil. However, the adsorption amount was less than those with other addition amounts of exogenous OM when the addition of exogenous OM was too high (> or = 30 g x kg(-1)). The addition of surfactant sodium dodecylbenzene sulfonic acid (SDBS) in purple soil increased the adsorption amount of DMP by purple soil. The adsorption amount was maximal when the addition amount of SDBS was 50 mg x kg(-1). However, the adsorption amounts decreased with increasing addition amounts of SDBS although the adsorption amounts were still more than that of the control group, and the adsorption amount was almost equal to that of the control group when the addition amount of SDBS was 800 mg x kg(-1). Continuous leaching time affected the vertical distribution of DMP in the soil column. When the leaching time was shorter, the upper soil column adsorbed more DMP, while the DMP concentrations in upper and lower soil columns became similar with the extension of leaching time.

  4. Transcriptome Analysis Identifies Key Candidate Genes Mediating Purple Ovary Coloration in Asiatic Hybrid Lilies

    Science.gov (United States)

    Xu, Leifeng; Yang, Panpan; Yuan, Suxia; Feng, Yayan; Xu, Hua; Cao, Yuwei; Ming, Jun

    2016-01-01

    Lily tepals have a short lifespan. Once the tepals senesce, the ornamental value of the flower is lost. Some cultivars have attractive purple ovaries and fruits which greatly enhance the ornamental value of Asiatic hybrid lilies. However, little is known about the molecular mechanisms of anthocyanin biosynthesis in Asiatic hybrid lily ovaries. To investigate the transcriptional network that governs purple ovary coloration in Asiatic hybrid lilies, we obtained transcriptome data from green ovaries (S1) and purple ovaries (S2) of Asiatic “Tiny Padhye”. Comparative transcriptome analysis revealed 4228 differentially expressed genes. Differential expression analysis revealed that ten unigenes including four CHS genes, one CHI gene, one F3H gene, one F3′H gene, one DFR gene, one UFGT gene, and one 3RT gene were significantly up-regulated in purple ovaries. One MYB gene, LhMYB12-Lat, was identified as a key transcription factor determining the distribution of anthocyanins in Asiatic hybrid lily ovaries. Further qPCR results showed unigenes related to anthocyanin biosynthesis were highly expressed in purple ovaries of three purple-ovaried Asiatic hybrid lilies at stages 2 and 3, while they showed an extremely low level of expression in ovaries of three green-ovaried Asiatic hybrid lilies during all developmental stages. In addition, shading treatment significantly decreased pigment accumulation by suppressing the expression of several unigenes related to anthocyanin biosynthesis in ovaries of Asiatic “Tiny Padhye”. Lastly, a total of 15,048 Simple Sequence Repeats (SSRs) were identified in 13,710 sequences, and primer pairs for SSRs were designed. The results could further our understanding of the molecular mechanisms of anthocyanin biosynthesis in Asiatic hybrid lily ovaries. PMID:27879624

  5. Correlated interaction fluctuations in photosynthetic complexes

    CERN Document Server

    Vlaming, Sebastiaan M

    2011-01-01

    The functioning and efficiency of natural photosynthetic complexes is strongly influenced by their embedding in a noisy protein environment, which can even serve to enhance the transport efficiency. Interactions with the environment induce fluctuations of the transition energies of and interactions between the chlorophyll molecules, and due to the fact that different fluctuations will partially be caused by the same environmental factors, correlations between the various fluctuations will occur. We argue that fluctuations of the interactions should in general not be neglected, as these have a considerable impact on population transfer rates, decoherence rates and the efficiency of photosynthetic complexes. Furthermore, while correlations between transition energy fluctuations have been studied, we provide the first quantitative study of the effect of correlations between interaction fluctuations and transition energy fluctuations, and of correlations between the various interaction fluctuations. It is shown t...

  6. Photosynthetic rates of citronella and lemongrass.

    Science.gov (United States)

    Herath, H M; Ormrod, D P

    1979-02-01

    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 meter(2) 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.

  7. Production of purple potato mackerel balls%紫薯鲐鱼鱼丸的制作

    Institute of Scientific and Technical Information of China (English)

    王岩

    2015-01-01

    Fish ball is popular among consumers for its deliciousness, nutritiousness and conven-ience. The mackerel and purple potato were taken as main raw materials to make fish balls. Through the quality evaluation,the effect of purple potato mackerel ball was satisfying.%鱼丸以其美味、营养与便捷倍受消费者青睐. 本文以紫薯和鲐鱼为主要原料试制紫薯鲐鱼丸,紫薯鲐鱼丸产品经质量评价,效果令人满意.

  8. 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.

  9. Nitrogen control of photosynthetic protein synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, G.W.

    1986-09-01

    Plant growth is severely affected by impaired photosynthesis resulting from nitrogen deficiency. The molecular aspects of this effect are being studied in the green alga Chlamydomonas grown in continuous culture systems. Photosynthetic membranes of nitrogen-limited cells are dramatically depleted in chlorophylls, xanthophylls and proteins of the light-harvesting complexes. In contrast, enzymes of the reductive pentose phosphate cycle and electron transport chain complexes are reduced only 40 to 65% on a per cell basis comparison with nitrogen-sufficient cultures. From analyses of mRNA levels by in vitro translation and hybridization analyses with cloned DNA sequences for photosynthetic proteins, we have found there are rather minor effects of nitrogen deficiency on nuclear or chloroplast gene transcription. Maturation of a transcript of the nuclear-encoded small subunit of ribulose 1,5-bisphosphate carboxylase is inhibited in nitrogen-deficient cells and causes accumulation of large amounts of mRNA precursors. Most of the effects of nitrogen deficiency on photosynthetic proteins appear to result from posttranscriptional regulatory processes: light-harvesting protein synthesis may be sustained but their import into chloroplasts or translocation to photosynthetic membranes is impaired. Nitrogen-deficient cells lack violaxanthin, a pigment that is essential for the structure, function and biogenesis of the major antenna complexes. The absence of this pigment may be a causative factor for the deficiency of light harvesting complexes. Finally, the accumulation of massive amounts of starch and triglycerides in nitrogen-limited cells indicate there are some genes whose maximal expression is dependent upon nitrogen-limiting conditions. 10 refs.

  10. Coral bleaching independent of photosynthetic activity.

    Science.gov (United States)

    Tolleter, Dimitri; Seneca, François O; DeNofrio, Jan C; Krediet, Cory J; Palumbi, Stephen R; Pringle, John R; Grossman, Arthur R

    2013-09-23

    The global decline of reef-building corals is due in part to the loss of algal symbionts, or "bleaching," during the increasingly frequent periods of high seawater temperatures. During bleaching, endosymbiotic dinoflagellate algae (Symbiodinium spp.) either are lost from the animal tissue or lose their photosynthetic pigments, resulting in host mortality if the Symbiodinium populations fail to recover. The >1,000 studies of the causes of heat-induced bleaching have focused overwhelmingly on the consequences of damage to algal photosynthetic processes, and the prevailing model for bleaching invokes a light-dependent generation of toxic reactive oxygen species (ROS) by heat-damaged chloroplasts as the primary trigger. However, the precise mechanisms of bleaching remain unknown, and there is evidence for involvement of multiple cellular processes. In this study, we asked the simple question of whether bleaching can be triggered by heat in the dark, in the absence of photosynthetically derived ROS. We used both the sea anemone model system Aiptasia and several species of reef-building corals to demonstrate that symbiont loss can occur rapidly during heat stress in complete darkness. Furthermore, we observed damage to the photosynthetic apparatus under these conditions in both Aiptasia endosymbionts and cultured Symbiodinium. These results do not directly contradict the view that light-stimulated ROS production is important in bleaching, but they do show that there must be another pathway leading to bleaching. Elucidation of this pathway should help to clarify bleaching mechanisms under the more usual conditions of heat stress in the light. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. 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

    2003-04-15

    This quarterly report documents significant achievements in the Enhanced Practical Photosynthetic CO{sub 2} Mitigation project during the period from 1/2/2003 through 4/01/2003. As indicated in the list of accomplishments below we are progressing with long-term model scale bioreactor tests and are completing final preparations for pilot scale bioreactor testing. Specific results and accomplishments for the first quarter of 2003 are included.

  12. Photosynthetic system in Blastochloris viridis revisited.

    Science.gov (United States)

    Konorty, Marina; Brumfeld, Vlad; Vermeglio, Andre; Kahana, Nava; Medalia, Ohad; Minsky, Abraham

    2009-06-09

    The bacterium Blastochloris viridis carries one of the simplest photosynthetic systems, which includes a single light-harvesting complex that surrounds the reaction center, membrane soluble quinones, and a soluble periplasmic protein cytochrome c(2) that shuttle between the reaction center and the bc(1) complex and act as electron carriers, as well as the ATP synthase. The close arrangement of the photosynthetic membranes in Bl. viridis, along with the extremely tight arrangement of the photosystems within these membranes, raises a fundamental question about the diffusion of the electron carriers. To address this issue, we analyzed the structure and response of the Bl. viridis photosynthetic system to various light conditions, by using a combination of electron microscopy, whole-cell cryotomography, and spectroscopic methods. We demonstrate that in response to high light intensities, the ratio of both cytochrome c(2) and bc(1) complexes to the reaction centers is increased. The shorter membrane stacks, along with the notion that the bc(1) complex is located at the highly curved edges of these stacks, result in a smaller average distance between the reaction centers and the bc(1) complexes, leading to shorter pathways of cytochrome c(2) between the two complexes. Under anaerobic conditions, the slow diffusion rate is further mitigated by keeping most of the quinone pool reduced, resulting in a concentration gradient of quinols that allows for a constant supply of theses electron carriers to the bc(1) complex.

  13. Studies on Photosynthetic Characteristics of Plum Leaves

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Many photosynthetic characteristics of three plum varieties were studied with a infrared CO2 analyzer. Results showed that plums belong to light-loving species,having a relative high light compensation point (75~ 80μmol · m-2 · s-1 ), In natural light range from none to 1400μmol · m-2s-1PAR,the light response curve of plum as a hyperbo and the net photosynthetic rate(Pn) in leavs increased with PA elevation. Pn of plum tree was 20 to 22.50mg CO2 · dm-1 · h-1 at 1380μmol · m-2 · s-1 PAR,indicating that plum was typi cal C3-type fruit tree. Diurnal change in Pn was a bimoal curve with the highest photosynthetic rate arising at about 10:00 a. m. indicated the clear“none-rest”characteristic in plum leaves. Among three varieties. SuiLi3 had the shortest“none-rest“time followed by JiLin6 and NuXinLi. Seasonal change in Pn was a bi modal curve with the first period of high Pn in late June and the second in late August. Pn in leaves decreased visibly in period of drought in Spring and Summer.

  14. First Results from the Relocated and Enhanced Purple Crow Lidar

    Science.gov (United States)

    Wing, R.; Argall, P. S.; Bandoro, J.; Khanna, J.; McCullough, E. M.; Sica, R. J.

    2011-12-01

    The University of Western Ontario's Purple Crow Lidar (PCL) has been in near continuous operation since 1993 and routinely measures temperature from 10 km to above 100 km, water vapor mixing ratio in the troposphere and stratosphere, as well as aerosol products. The PCL was recently relocated to a new custom-built, environmentally friendly facility at Western's Environmental Research Station located 9 km north of the campus. The PCL move allowed the opportunity for many new and exciting instrumentation upgrades and improvements. Our new transmitter, a Litron Nd:YAG laser, produces 1000 mJ/pulse at 532 nm with a 30 Hz repetition rate (i.e. 30 W). This new laser increases our transmitter power by 2.5 times compared to our previous laser and boosts the PCL's power-aperture product to 160 W/m2. We have also upgraded the counting electronics to improve the vertical height resolution of our Rayleigh temperature from 24 m to 7.5 m and our water vapour, vibrational Raman temperature, and aerosol measurements from 250 m to 24 m. As well, the system is now capable of automatic alignment during operations. The water vapor measurements have been further improved by the addition of a white light calibration source. We are in the process of upgrading the system for more direct aerosol measurements by including a low altitude aerosol channel using a small co-aligned telescope. The enhanced system will have two major impacts on upper mesosphere/lower thermosphere science. First, our new laser will allow our temperature measurements to gain another 10 km in altitude, pushing them at times above 110 km. Second, due to the new inversion method developed by Khanna (2011), an assumption of a seed pressure at the top of the atmosphere will no longer be required, so any systematic retrieval uncertainties will be less than the measurement statistical uncertainty in the lower thermosphere. With the seeding of the temperature profiles now done at the lowest heights (i.e. stratosphere), the

  15. Reverse evolution: driving forces behind the loss of acquired photosynthetic traits.

    Directory of Open Access Journals (Sweden)

    Francisco de Castro

    Full Text Available The loss of photosynthesis has occurred often in eukaryotic evolution, even more than its acquisition, which occurred at least nine times independently and which generated the evolution of the supergroups Archaeplastida, Rhizaria, Chromalveolata and Excavata. This secondary loss of autotrophic capability is essential to explain the evolution of eukaryotes and the high diversity of protists, which has been severely underestimated until recently. However, the ecological and evolutionary scenarios behind this evolutionary "step back" are still largely unknown.Using a dynamic model of heterotrophic and mixotrophic flagellates and two types of prey, large bacteria and ultramicrobacteria, we examine the influence of DOC concentration, mixotroph's photosynthetic growth rate, and external limitations of photosynthesis on the coexistence of both types of flagellates. Our key premises are: large bacteria grow faster than small ones at high DOC concentrations, and vice versa; and heterotrophic flagellates are more efficient than the mixotrophs grazing small bacteria (both empirically supported. We show that differential efficiency in bacteria grazing, which strongly depends on cell size, is a key factor to explain the loss of photosynthesis in mixotrophs (which combine photosynthesis and bacterivory leading to purely heterotrophic lineages. Further, we show in what conditions an heterotroph mutant can coexist, or even out-compete, its mixotrophic ancestor, suggesting that bacterivory and cell size reduction may have been major triggers for the diversification of eukaryotes.Our results suggest that, provided the mixotroph's photosynthetic advantage is not too large, the (small heterotroph will also dominate in nutrient-poor environments and will readily invade a community of mixotrophs and bacteria, due to its higher efficiency exploiting the ultramicrobacteria. As carbon-limited conditions were presumably widespread throughout Earth history, such a

  16. Ultra-broadband 2D electronic spectroscopy of carotenoid-bacteriochlorophyll interactions in the LH1 complex of a purple bacterium

    Energy Technology Data Exchange (ETDEWEB)

    Maiuri, Margherita [CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, P.zza L. da Vinci 32, Milano 20133 (Italy); Department of Chemistry, Princeton University, Washington Road, Princeton, New Jersey 08544 (United States); Réhault, Julien; Polli, Dario; Cerullo, Giulio, E-mail: giulio.cerullo@polimi.it [CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, P.zza L. da Vinci 32, Milano 20133 (Italy); Carey, Anne-Marie; Hacking, Kirsty; Cogdell, Richard J. [Glasgow Biomedical Research Centre, IBLS, University of Glasgow, 126 Place, Glasgow G12 8TA, Scotland (United Kingdom); Garavelli, Marco [Dipartimento di Chimica “G. Ciamician,” Università di Bologna, Via Selmi 2, IT-40126 Bologna (Italy); CNRS, Institut de Chimie de Lyon, École Normale Supérieure de Lyon, Université de Lyon, 46 Allée d’Italie, F-69364 Lyon Cedex 07 (France); Lüer, Larry [Madrid Institute for Advanced Studies, IMDEA Nanociencia, Madrid (Spain)

    2015-06-07

    We investigate the excitation energy transfer (EET) pathways in the photosynthetic light harvesting 1 (LH1) complex of purple bacterium Rhodospirillum rubrum with ultra-broadband two-dimensional electronic spectroscopy (2DES). We employ a 2DES apparatus in the partially collinear geometry, using a passive birefringent interferometer to generate the phase-locked pump pulse pair. This scheme easily lends itself to two-color operation, by coupling a sub-10 fs visible pulse with a sub-15-fs near-infrared pulse. This unique pulse combination allows us to simultaneously track with extremely high temporal resolution both the dynamics of the photoexcited carotenoid spirilloxanthin (Spx) in the visible range and the EET between the Spx and the B890 bacterio-chlorophyll (BChl), whose Q{sub x} and Q{sub y} transitions peak at 585 and 881 nm, respectively, in the near-infrared. Global analysis of the one-color and two-color 2DES maps unravels different relaxation mechanisms in the LH1 complex: (i) the initial events of the internal conversion process within the Spx, (ii) the parallel EET from the first bright state S{sub 2} of the Spx towards the Q{sub x} state of the B890, and (iii) the internal conversion from Q{sub x} to Q{sub y} within the B890.

  17. Ultra-broadband 2D electronic spectroscopy of carotenoid-bacteriochlorophyll interactions in the LH1 complex of a purple bacterium

    Science.gov (United States)

    Maiuri, Margherita; Réhault, Julien; Carey, Anne-Marie; Hacking, Kirsty; Garavelli, Marco; Lüer, Larry; Polli, Dario; Cogdell, Richard J.; Cerullo, Giulio

    2015-06-01

    We investigate the excitation energy transfer (EET) pathways in the photosynthetic light harvesting 1 (LH1) complex of purple bacterium Rhodospirillum rubrum with ultra-broadband two-dimensional electronic spectroscopy (2DES). We employ a 2DES apparatus in the partially collinear geometry, using a passive birefringent interferometer to generate the phase-locked pump pulse pair. This scheme easily lends itself to two-color operation, by coupling a sub-10 fs visible pulse with a sub-15-fs near-infrared pulse. This unique pulse combination allows us to simultaneously track with extremely high temporal resolution both the dynamics of the photoexcited carotenoid spirilloxanthin (Spx) in the visible range and the EET between the Spx and the B890 bacterio-chlorophyll (BChl), whose Qx and Qy transitions peak at 585 and 881 nm, respectively, in the near-infrared. Global analysis of the one-color and two-color 2DES maps unravels different relaxation mechanisms in the LH1 complex: (i) the initial events of the internal conversion process within the Spx, (ii) the parallel EET from the first bright state S2 of the Spx towards the Qx state of the B890, and (iii) the internal conversion from Qx to Qy within the B890.

  18. Ultra-broadband 2D electronic spectroscopy of carotenoid-bacteriochlorophyll interactions in the LH1 complex of a purple bacterium.

    Science.gov (United States)

    Maiuri, Margherita; Réhault, Julien; Carey, Anne-Marie; Hacking, Kirsty; Garavelli, Marco; Lüer, Larry; Polli, Dario; Cogdell, Richard J; Cerullo, Giulio

    2015-06-01

    We investigate the excitation energy transfer (EET) pathways in the photosynthetic light harvesting 1 (LH1) complex of purple bacterium Rhodospirillum rubrum with ultra-broadband two-dimensional electronic spectroscopy (2DES). We employ a 2DES apparatus in the partially collinear geometry, using a passive birefringent interferometer to generate the phase-locked pump pulse pair. This scheme easily lends itself to two-color operation, by coupling a sub-10 fs visible pulse with a sub-15-fs near-infrared pulse. This unique pulse combination allows us to simultaneously track with extremely high temporal resolution both the dynamics of the photoexcited carotenoid spirilloxanthin (Spx) in the visible range and the EET between the Spx and the B890 bacterio-chlorophyll (BChl), whose Qx and Qy transitions peak at 585 and 881 nm, respectively, in the near-infrared. Global analysis of the one-color and two-color 2DES maps unravels different relaxation mechanisms in the LH1 complex: (i) the initial events of the internal conversion process within the Spx, (ii) the parallel EET from the first bright state S2 of the Spx towards the Qx state of the B890, and (iii) the internal conversion from Qx to Qy within the B890.

  19. Exogenous quinones inhibit photosynthetic electron transfer in Chloroflexus aurantiacus by specific quenching of the excited bacteriochlorophyll c antenna

    DEFF Research Database (Denmark)

    Frigaard, N-U; Tokita, S; Matsuura, K

    1999-01-01

    In the photosynthetic green filamentous bacterium Chloroflexus aurantiacus, excitation energy is transferred from a large bacteriochlorophyll (BChl) c antenna via smaller BChl a antennas to the reaction center. The effects of substituted 1,4-naphthoquinones on BChl c and BChl a fluorescence and o...... antenna. Our results provide a model system for studying the redox-dependent antenna quenching in green sulfur bacteria because the antennas in these bacteria inherently exhibit a sensitivity to O(2) similar to the quinone-supplemented cells of Cfx. aurantiacus....

  20. A multi-pathway model for Photosynthetic reaction center

    CERN Document Server

    Qin, M; Yi, X X

    2015-01-01

    Charge separation in light-harvesting complexes occurs in a pair of tightly coupled chlorophylls at the heart of photosynthetic reaction centers of both plants and bacteria. Recently it has been shown that quantum coherence can, in principle, enhance the efficiency of a solar cell, working like a quantum heat engine (QHE). Here, we propose a biological quantum heat engine (BQHE) motivated by Photosystem {\\rm II} reaction center (PS{\\rm II} RC) to describe the charge separation. Our model mainly considers two charge-separation pathways more than that in the published literature. The two pathways can interfere via cross-couplings and work together to enhance the charge-separation yields. We explore how these cross-couplings increase the current and voltage of the charge separation and discuss the advantages of multiple pathways in terms of current and power. The robustness of the BQHE against the charge recombination in natural PS{\\rm II} RC and dephasing induced by environments is also explored, and extension ...

  1. Protein translocons in photosynthetic organelles of Paulinella chromatophora

    Directory of Open Access Journals (Sweden)

    Przemysław Gagat

    2014-12-01

    Full Text Available The rhizarian amoeba Paulinella chromatophora harbors two photosynthetic cyanobacterial endosymbionts (chromatophores, acquired independently of primary plastids of glaucophytes, red algae and green plants. These endosymbionts have lost many essential genes, and transferred substantial number of genes to the host nuclear genome via endosymbiotic gene transfer (EGT, including those involved in photosynthesis. This indicates that, similar to primary plastids, Paulinella endosymbionts must have evolved a transport system to import their EGT-derived proteins. This system involves vesicular trafficking to the outer chromatophore membrane and presumably a simplified Tic-like complex at the inner chromatophore membrane. Since both sequenced Paulinella strains have been shown to undergo differential plastid gene losses, they do not have to possess the same set of Toc and Tic homologs. We searched the genome of Paulinella FK01 strain for potential Toc and Tic homologs, and compared the results with the data obtained for Paulinella CCAC 0185 strain, and 72 cyanobacteria, eight Archaeplastida as well as some other bacteria. Our studies revealed that chromatophore genomes from both Paulinella strains encode the same set of translocons that could potentially create a simplified but fully-functional Tic-like complex at the inner chromatophore membranes. The common maintenance of the same set of translocon proteins in two Paulinella strains suggests a similar import mechanism and/or supports the proposed model of protein import. Moreover, we have discovered a new putative Tic component, Tic62, a redox sensor protein not identified in previous comparative studies of Paulinella translocons.

  2. Thermal Quantum Correlations in Photosynthetic Light-Harvesting Complexes

    Science.gov (United States)

    Mahdian, M.; Kouhestani, H.

    2015-08-01

    Photosynthesis is one of the ancient biological processes, playing crucial role converting solar energy to cellular usable currency. Environmental factors and external perturbations has forced nature to choose systems with the highest efficiency and performance. Recent theoretical and experimental studies have proved the presence of quantum properties in biological systems. Energy transfer systems like Fenna-Matthews-Olson (FMO) complex shows quantum entanglement between sites of Bacteriophylla molecules in protein environment and presence of decoherence. Complex biological systems implement more truthful mechanisms beside chemical-quantum correlations to assure system's efficiency. In this study we investigate thermal quantum correlations in FMO protein of the photosynthetic apparatus of green sulfur bacteria by quantum discord measure. The results confirmed existence of remarkable quantum correlations of of BChla pigments in room temperature. This results approve involvement of quantum correlation mechanisms for information storage and retention in living organisms that could be useful for further evolutionary studies. Inspired idea of this study is potentially interesting to practice by the same procedure in genetic data transfer mechanisms.

  3. Evaluation of maturity group III soybean lines for resistance to purple seed stain in Mississippi, 2010

    Science.gov (United States)

    Purple seed stain (PSS) of soybean is an important disease caused by Cercospora kikuchii. PSS reduces seed quality and market grade, affects seed germination and vigor, and has been reported wherever soybeans are grown worldwide. In 2009, PSS caused 6.4 million bushels of yield losses in 16 southern...

  4. Evaluation of maturity group IV soybean lines for resistance to purple seed stains in Mississippi 2010

    Science.gov (United States)

    Purple seed stain (PSS) of soybean is an important disease caused by Cercospora kikuchii. PSS reduces seed quality and market grade, affects seed germination and vigor, and has been reported wherever soybeans are grown worldwide. In 2009, PSS caused 6.4 million bushels of yield losses in 16 southern...

  5. Reaction of maturity group V soybean lines to purple seed stains in Mississippi 2010

    Science.gov (United States)

    In 2009, soybean purple seed stain (PSS) caused 6.4 million bushels of yield losses in 16 southern states. This disease severely reduces seed market grade and affects seed germination and vigor. PSS is caused by Cercospora kikuchii and is an economy important disease. To identify new sources of resi...

  6. Inheritance of and molecular markers for purple seed stain resistance in soybean

    Science.gov (United States)

    Purple seed stain (PSS) caused by Cercospora kikuchii, is an important disease of soybean, causing seed quality deterioration. Use of genetic resistance is the most practical and economical way to control the disease. The objectives of this research were to investigate the inheritance of resistance...

  7. Peter Wilcox: A new purple-skin, yellow flesh fresh market potato cultivar

    Science.gov (United States)

    Peter Wilcox is a new, medium-maturing, purple-skin, yellow-flesh potato cultivar for fresh market. Peter Wilcox also produces light-colored chips, although it is being released primarily as a fresh market potato because of its skin and flesh colors. Tubers of Peter Wilcox are attractive, smooth, wi...

  8. A View from the Mountain Top: The Purple Mountain Observatory Library, China

    Science.gov (United States)

    Zhang, Jian

    2012-01-01

    This paper discusses the author's experience directing the Purple Mountain Observatory Library, Chinese Academy of Sciences (CAS) in Nanjing, China. Routine collection development, management and preservation issues are described, and the unique challenges and opportunities involved in operating a remote observatory library are highlighted.

  9. Analytic Reading of The Color Purple the Death and Rebirth of Dreams

    Institute of Scientific and Technical Information of China (English)

    宋少华

    2008-01-01

    The Color Purple for the first time not only reveals the racial and sexual discrimination but also tells those oppressed black women the way to solve it. The paper is trying to analyze the work from the heroines (their main experiences and connections with each other), the linguistic arts and the motifs, etc.

  10. Effect of the Purple Corn Beverage "Chicha Morada" in Composite Resin during Dental Bleaching.

    Science.gov (United States)

    Acuña, Eric Dario; Delgado-Cotrina, Leyla; Rumiche, Francisco Aurelio; Tay, Lidia Yileng

    2016-01-01

    During dental bleaching the staining potential of the surface would increase. This study aims to evaluate the staining susceptibility of one bleached composite resin after the exposure to three different beverages: Peruvian purple corn based beverage (chicha morada), green tea, and distilled water. Thirty disk-shaped specimens of one nanofill composite resin were prepared. The specimens were then divided into six groups (n = 5): purple corn (P), purple corn + bleaching (PB), green tea (T), green tea + bleaching (TB), distilled water (W), and distilled water + bleaching (WB). In groups that received bleaching, two sessions of bleaching with 35% hydrogen peroxide were done. Following bleaching, specimens were exposed to each liquid thirty minutes daily. Color was measured with a digital spectrophotometer. For statistical analysis, color measurement differences between the obtained results were used: during bleaching, after bleaching, and during + after bleaching. Two-way ANOVA was used to compare the color changes in the resins of all groups (p composite resin regardless of the bleaching procedure. However, purple corn was the only beverage that caused a perceptible color change (ΔE > 3.3).

  11. Construction and characterization of an azurin analog for the purple copper site in cytochrome c oxidase.

    Science.gov (United States)

    Hay, M; Richards, J H; Lu, Y

    1996-01-09

    A protein analog of a purple copper center has been constructed from a recombinant blue copper protein (Pseudomonas aeruginosa azurin) by replacing the loop containing the three ligands to the blue copper center with the corresponding loop of the CuA center in cytochrome c oxidase (COX) from Paracoccus denitrificans. The electronic absorption in the UV and visible region (UV-vis) and electron paramagnetic resonance (EPR) spectra of this analog are remarkably similar to those of the native CuA center in COX from Paracoccus denitrificans. The above spectra can be obtained upon addition of a mixture of Cu2+ and Cu+. Addition of Cu2+ only results in a UV-vis spectrum consisting of absorptions from both a purple copper center and a blue copper center. This spectrum can be converted to the spectrum of a pure purple copper by a prolonged incubation in the air, or by addition of excess ascorbate. The azurin mutant reported here is an example of an engineered purple copper center with the A480/A530 ratio greater than 1 and with no detectable hyperfines, similar to those of the CuA sites in COX of bovine heart and of Paracoccus denitrificans.

  12. 50 CFR 21.45 - Depredation order for depredating purple gallinules in Louisiana.

    Science.gov (United States)

    2010-10-01

    ..., EXPORTATION, AND IMPORTATION OF WILDLIFE AND PLANTS (CONTINUED) MIGRATORY BIRD PERMITS Control of Depredating... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Depredation order for depredating purple gallinules in Louisiana. 21.45 Section 21.45 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE...

  13. Development of a frozen yogurt fortified with a nano-emulsion containing purple rice bran oil

    Science.gov (United States)

    The objectives of this study were to develop and evaluate a frozen yogurt (FY) fortified with a nano-emulsion containing purple rice bran oil (NPRBO). A nano-emulsion with a droplet size range of 150-300 nm was produced by sonication followed by ultra-shear homogenization. The nano-emulsion was mi...

  14. Literary Techniques Employed to Develop Celie's Character in The Color Purple

    Institute of Scientific and Technical Information of China (English)

    褚妍

    2014-01-01

    In 1982, Alice Walker's The Color Purple, was published and became one of the best sellers. As the novel progressed, Celie's acquiescent behavior transformed into one of resilience and dignity. By incorporating the literary techniques of tone, symbolism, and juxtaposition into her novel, Alice Walker was able to develop Celie's character, emphasizing her progression from subservience to independence.

  15. Alexandrite-like effect in purple flowers analyzed with newly devised round RGB diagram

    Science.gov (United States)

    Kasajima, Ichiro

    2016-07-01

    The gemstone alexandrite is known for its feature to change color depending on the spectral quality of the incident light. Thus, the stone looks green when illuminated by white LED light but looks red when illuminated by incandescent light. This effect (alexandrite effect) is caused by a special relationship between the spectral quality of the incident light and the absorbance spectrum of the stone. Here we report an alexandrite-like effect in the petals of torenia and cyclamen flowers. These flowers are purple in sunlight but magenta (reddish) in incandescent light, and violet (bluish purple) in white LED light. The m-n, triangle and round diagrams are devised to calculate the colors of visible light spectra, based on the RGB color-matching function. Using these calculations, the alexandrite-like effect in purple flowers was successfully analyzed in terms of the interaction between the incident light spectrum and the absorbance spectrum of their purple anthocyanin. This analysis allows both logical and intuitive understanding of the colors exhibited by any object showing alexandrite–like properties.

  16. LC-PDA-EIS/MSn identification of new anthocyanins in purple radish (Raphanus sativus L. variety)

    Science.gov (United States)

    An LC-PDA-ESI/MSn profiling method was used for a comprehensive study of the anthocyanins of purple Bordeaux radish. This study identified 57 anthocyanins: 23 acylated cyanidin 3-sophoroside-5-diglucosides, 12 acylated cyanidin 3-(glucosylacyl) acylsophoroside-5-diglucosides, and 22 acylated cyanid...

  17. Anthocyanin, phenolics and antioxidant activity changes in purple waxy corn as affected by traditional cooking

    Science.gov (United States)

    Antioxidant components, including anthocyanins and phenolic compounds, antioxidant activity, and their changes during traditional cooking of fresh purple waxy corn were investigated. As compared to the raw corn, thermal treatment caused significant (p < 0.05) decreases in each antioxidant compound a...

  18. Purple sweet potato (Ipomea Batatas P. as dentin hypersensitivity desensitization gel

    Directory of Open Access Journals (Sweden)

    Chariza Hanum Mayvita Iskandar

    2015-12-01

    Full Text Available Background: Dentin hypersensitivity is a short sharp sense of pain in the teeth when exposed to excitatory stimulus. A total of 74% of world population experiencing dentin hypersensitivity. Home treatment topical desensitization is rarely found in Indonesia. The use of dentrifice is less practical because it must be done with regular brushing. Indonesia has abundant natural resources, one of which is purple sweet potato. Purple sweet potato (Ipomea Batatas P. has highest potasium ions compared to other foodstuffs. Potassium ions can be a solution of dentin hypersensitivity by temporary blocking the suffix pulp nerve impulses. Purpose: The research objective was to determine the effectiveness of the 10% purple sweet potato extract gel of the dental pain threshold score. Method: An experimental study carried out by dental pain threshold score measurements using vitality tester into the teeth with gum recession. Samples included 32 respondents with a single blind and pre-post test control group design. They were divided into treatment group and negative control group. Paired T-test and Wilcoxon were used as data analysis. Result: The results showed dental pain threshold score increasing either in treatment group and negative control, although not as significant as in the treatment group. Conclusion: 10% purple sweet potato extract gel containing potassium ions is able to reduce the pain of dentin hypersensitivity.

  19. Purple Computational Environment With Mappings to ACE Requirements for the General Availability User Environment Capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Barney, B; Shuler, J

    2006-08-21

    Purple is an Advanced Simulation and Computing (ASC) funded massively parallel supercomputer located at Lawrence Livermore National Laboratory (LLNL). The Purple Computational Environment documents the capabilities and the environment provided for the FY06 LLNL Level 1 General Availability Milestone. This document describes specific capabilities, tools, and procedures to support both local and remote users. The model is focused on the needs of the ASC user working in the secure computing environments at Los Alamos National Laboratory, Lawrence Livermore National Laboratory, and Sandia National Laboratories, but also documents needs of the LLNL and Alliance users working in the unclassified environment. Additionally, the Purple Computational Environment maps the provided capabilities to the Trilab ASC Computing Environment (ACE) Version 8.0 requirements. The ACE requirements reflect the high performance computing requirements for the General Availability user environment capabilities of the ASC community. Appendix A lists these requirements and includes a description of ACE requirements met and those requirements that are not met for each section of this document. The Purple Computing Environment, along with the ACE mappings, has been issued and reviewed throughout the Tri-lab community.

  20. Rhizosphere Bacteria

    Directory of Open Access Journals (Sweden)

    N.V. Feoktistova

    2016-06-01

    Full Text Available The review deals with the analysis of modern literature data on rhizosphere bacteria and their role in plant life. The structure of rhizosphere has been characterized. The role of plants as the centers of formation of microbial communities has been shown. Data on the main groups of microorganisms inhabiting the rhizosphere have been provided. The associative relationship between rhizobacteria and partner plants has been investigated. The modern concept of holobiont defined as the whole host plant organism and microorganisms associated with it has been reviewed. The role of rhizobacteria in the processes of nitrogen fixation has been discussed in detail. The mechanisms of direct stimulation of plant growth by biosynthesis of phytohormones, improvement of phosphorus and nitrogen nutrition, increase in resistance to stress, and stimulation mediated by antagonism against pathogenic microorganisms have been analyzed. The criteria for selection of rhizobacteria for practical purposes have been discussed.

  1. 紫薯挂面加工工艺研究%Processing Technology of Vermicelli with Purple Sweet Potato

    Institute of Scientific and Technical Information of China (English)

    苑建伟; 谢新华; 李巍

    2014-01-01

    以小麦粉和紫薯为主要原料,采用以紫薯泥代替紫薯淀粉的方法,对紫薯挂面的制作工艺进行研究。通过正交试验确定了生产紫薯挂面的最佳配方为紫薯与小麦粉比例3∶7、水添加量31%和谷朊粉添加量1.5%。用此配方生产的紫薯挂面色泽鲜艳,具有紫薯特有的香味,断条率低,口感良好,营养丰富。%Taking wheat flour and purple sweet potato as raw material, new technology of adding purple mashed potatoes instead of purple sweet potato starch was applied to study production process of purple sweet potato vermicelli. Optimum parameters of vermicelli with purple sweet potato were confirmed by orthogonal experiment.Results showed that ratio of purple sweet potato to wheat flour was 3∶7, water was 31%, wheat gluten was 1.5%.Product had bright color, special purple sweet potato flavor, low rate of broken bars, good taste and rich in nutrition.

  2. A compendium of temperature responses of Rubisco kinetic traits: variability among and within photosynthetic groups and impacts on photosynthesis modeling.

    Science.gov (United States)

    Galmés, Jeroni; Hermida-Carrera, Carmen; Laanisto, Lauri; Niinemets, Ülo

    2016-09-01

    The present study provides a synthesis of the in vitro and in vivo temperature responses of Rubisco Michaelis-Menten constants for CO2 (Kc) and O2 (Ko), specificity factor (Sc,o) and maximum carboxylase turnover rate (kcatc) for 49 species from all the main photosynthetic kingdoms of life. Novel correction routines were developed for in vitro data to remove the effects of study-to-study differences in Rubisco assays. The compilation revealed differences in the energy of activation (∆Ha) of Rubisco kinetics between higher plants and other photosynthetic groups, although photosynthetic bacteria and algae were under-represented and very few species have been investigated so far. Within plants, the variation in Rubisco temperature responses was related to species' climate and photosynthetic mechanism, with differences in ∆Ha for kcatc among C3 plants from cool and warm environments, and in ∆Ha for kcatc and Kc among C3 and C4 plants. A negative correlation was observed among ∆Ha for Sc/o and species' growth temperature for all data pooled, supporting the convergent adjustment of the temperature sensitivity of Rubisco kinetics to species' thermal history. Simulations of the influence of varying temperature dependences of Rubisco kinetics on Rubisco-limited photosynthesis suggested improved photosynthetic performance of C3 plants from cool habitats at lower temperatures, and C3 plants from warm habitats at higher temperatures, especially at higher CO2 concentration. Thus, variation in Rubisco kinetics for different groups of photosynthetic organisms might need consideration to improve prediction of photosynthesis in future climates. Comparisons between in vitro and in vivo data revealed common trends, but also highlighted a large variability among both types of Rubisco kinetics currently used to simulate photosynthesis, emphasizing the need for more experimental work to fill in the gaps in Rubisco datasets and improve scaling from enzyme kinetics to realized

  3. Multidimensional Ultrafast Spectroscopy of Photosynthetic Pigment-Protein Complexes

    OpenAIRE

    De Re, Eleonora

    2014-01-01

    This dissertation presents the application of ultrafast spectroscopy to the investigation of pigment-protein complexes (PPCs) involved in energy transfer and energy dissipation in photosynthetic organisms. PPCs are the building blocks of all photosynthetic organisms, and within individual pigment-protein complexes, energy transfer dynamics occur over fast timescales and broad spectral regions. Chapter 1 gives an introduction to the capability of photosynthetic organisms to absorb light energy...

  4. Enhanced rate of intramolecular electron transfer in an engineered purple CuA azurin.

    Science.gov (United States)

    Farver, O; Lu, Y; Ang, M C; Pecht, I

    1999-02-02

    The recent expression of an azurin mutant where the blue type 1 copper site is replaced by the purple CuA site of Paracoccus denitrificans cytochrome c oxidase has yielded an optimal system for examining the unique electron mediation properties of the binuclear CuA center, because both type 1 and CuA centers are placed in the same location in the protein while all other structural elements remain the same. Long-range electron transfer is induced between the disulfide radical anion, produced pulse radiolytically, and the oxidized binuclear CuA center in the purple azurin mutant. The rate constant of this intramolecular process, kET = 650 +/- 60 s-1 at 298 K and pH 5.1, is almost 3-fold faster than for the same process in the wild-type single blue copper azurin from Pseudomonas aeruginosa (250 +/- 20 s-1), in spite of a smaller driving force (0.69 eV for purple CuA azurin vs. 0.76 eV for blue copper azurin). The reorganization energy of the CuA center is calculated to be 0.4 eV, which is only 50% of that found for the wild-type azurin. These results represent a direct comparison of electron transfer properties of the blue and purple CuA sites in the same protein framework and provide support for the notion that the binuclear purple CuA center is a more efficient electron transfer agent than the blue single copper center because reactivity of the former involves a lower reorganization energy.

  5. Multiscale Analysis and Optimisation of Photosynthetic Solar Energy Systems

    CERN Document Server

    Ringsmuth, Andrew K

    2014-01-01

    This work asks how light harvesting in photosynthetic systems can be optimised for economically scalable, sustainable energy production. Hierarchy theory is introduced as a system-analysis and optimisation tool better able to handle multiscale, multiprocess complexities in photosynthetic energetics compared with standard linear-process analysis. Within this framework, new insights are given into relationships between composition, structure and energetics at the scale of the thylakoid membrane, and also into how components at different scales cooperate under functional objectives of the whole photosynthetic system. Combining these reductionistic and holistic analyses creates a platform for modelling multiscale-optimal, idealised photosynthetic systems in silico.

  6. Microspectroscopy of the photosynthetic compartment of algae.

    Science.gov (United States)

    Evangelista, Valtere; Frassanito, Anna Maria; Passarelli, Vincenzo; Barsanti, Laura; Gualtieri, Paolo

    2006-01-01

    We performed microspectroscopic evaluation of the pigment composition of the photosynthetic compartments of algae belonging to different taxonomic divisions and higher plants. The feasibility of microspectroscopy for discriminating among species and/or phylogenetic groups was tested on laboratory cultures. Gaussian bands decompositions and a fitting algorithm, together with fourth-derivative transformation of absorbance spectra, provided a reliable discrimination among chlorophylls a, b and c, phycobiliproteins and carotenoids. Comparative analysis of absorption spectra highlighted the evolutionary grouping of the algae into three main lineages in accordance with the most recent endosymbiotic theories.

  7. Simulation of photosynthetic production using neural network

    Science.gov (United States)

    Kmet, Tibor; Kmetova, Maria

    2013-10-01

    This paper deals with neural network based optimal control synthesis for solving optimal control problems with control and state constraints and discrete time delay. The optimal control problem is transcribed into nonlinear programming problem which is implemented with adaptive critic neural network. This approach is applicable to a wide class of nonlinear systems. The proposed simulation methods is illustrated by the optimal control problem of photosynthetic production described by discrete time delay differential equations. Results show that adaptive critic based systematic approach holds promise for obtaining the optimal control with control and state constraints.

  8. CsmA Protein is Associated with BChl a in the Baseplate Subantenna of Chlorosomes of the Photosynthetic Green Filamentous Bacterium Oscillochloris trichoides belonging to the Family Oscillochloridaceae

    Directory of Open Access Journals (Sweden)

    Anastasiya Zobova

    2011-01-01

    Full Text Available The baseplate subantenna in chlorosomes of green anoxygenic photosynthetic bacteria, belonging to the families Chloroflexaceae and Chlorobiaceae, is known to represent a complex of bacteriochlorophyll (BChl a with the ~6 kDa CsmA proteins. Earlier, we showed the existence of a similar BChl a subantenna in chlorosomes of the photosynthetic green bacterium Oscillochloris trichoides, member of Oscillochloridaceae, the third family of green photosynthetic bacteria. However, this BChl a subantenna was not visually identified in absorption spectra of isolated Osc. trichoides chlorosomes in contrast to those of Chloroflexaceae and Chlorobiaceae. In this work, using room and low-temperature absorbance and fluorescence spectroscopy and sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of alkaline-treated and untreated chlorosomes of Osc. trichoides, we showed that the baseplate BChl a subantenna does exist in Oscillochloridaceae chlorosomes as a complex of BChl a with the 5.7 kDa CsmA protein. The present results support the idea that the baseplate subantenna, representing a complex of BChl a with a ~6 kDa CsmA protein, is a universal interface between the BChl c subantenna of chlorosomes and the nearest light-harvesting BChl a subantenna in all three known families of green anoxygenic photosynthetic bacteria.

  9. Respiratory processes in non-photosynthetic plastids

    Directory of Open Access Journals (Sweden)

    Marta eRenato

    2015-07-01

    Full Text Available Chlororespiration is a respiratory process located in chloroplast thylakoids which consists in an electron transport chain from NAD(PH to oxygen. This respiratory chain involves the NAD(PH dehydrogenase complex, the plastoquinone pool and the plastid terminal oxidase (PTOX, and it probably acts as a safety valve to prevent the over-reduction of the photosynthetic machinery in stress conditions. The existence of a similar respiratory activity in non-photosynthetic plastids has been less studied. Recently, it has been reported that tomato fruit chromoplasts present an oxygen consumption activity linked to ATP synthesis. Etioplasts and amyloplasts contain several electron carriers and some subunits of the ATP synthase, so they could harbor a similar respiratory process. This review provides an update on the study about respiratory processes in chromoplasts, identifying the major gaps that need to be addressed in future research. It also reviews the proteomic data of etioplasts and amyloplasts, which suggest the presence of a respiratory electron transport chain in these plastids.

  10. Non-photosynthetic pigments as potential biosignatures

    Science.gov (United States)

    Schwieterman, E. W.; Cockell, C. S.; Meadows, V. S.

    2014-03-01

    Photosynthetic organisms on Earth produce potentially detectable surface reflectance biosignatures due in part to the spectral location and strength of pigment absorption. However, life on Earth uses pigments for a multitude of purposes other than photosynthesis, including coping with extreme environments. Macroscopic environments exist on Earth where the surface reflectance is significantly altered by a nonphotosynthetic pigment, such as the case of hypersaline lakes and ponds (Oren et al. 1992). Here we explore the nature and potential detectability of non-photosynthetic pigments in disk-averaged planetary observations using a combination of laboratory measurements and archival reflectance spectra, along with simulated broadband photometry and spectra. The in vivo visible reflectance spectra of a cross section of pigmented microorganisms are presented to illustrate the spectral diversity of biologically produced pigments. Synthetic broadband colors are generated to show a significant spread in color space. A 1D radiative transfer model (Meadows & Crisp 1996; Crisp 1997) is used to approximate the spectra of scenarios where pigmented organisms are widespread on planets with Earth-like atmospheres. Broadband colors are revisited to show that colors due to surface reflectivity are not robust to the addition of scattering and absorption effects from the atmosphere. We consider a èbest case' plausible scenario for the detection of nonphotosynthetic pigments by using the Virtual Planetary Laboratory's 3D spectral Earth model (Robinson et al. 2011) to explore the detectability of the surface biosignature produced by pigmented halophiles that are widespread on an Earth-analog planet.

  11. Detection of Quorum Sensing Signals in Gram-Negative Bacteria by Using Reporter Strain CV026

    Directory of Open Access Journals (Sweden)

    Ahmad Humayan KABIR

    2010-12-01

    Full Text Available Quorum sensing signals are referred to as acylated homoserine lactones (AHL that are mainly found in Gram-negative bacteria. It implies the ability of certain bacteria of producing different AHL molecules. The bacteria Pseudomonas aureofaciens and Xenorhabdus nematophila were cultured in Luria-Bertani (LB10 media and CV026 was used as a reporter strain to detect the presence of AHLs produced by the cultured bacteria. In this study, the reporter strain has revealed the quorum sensing ability of P. aureofaciens and X. nematophila by producing the purple pigment violacein in the supply of external AHLs molecules. Thin layer chromatography (TLC bioassay having four controls was conducted to detect specific AHL molecule supplied by P. aureofaciens and X. nematophila. The specific AHL molecule was observed to be migrated according to their polarity on the TLC plate.

  12. Low-concentration, continuous brachial plexus block in the management of Purple Glove Syndrome: a case report

    OpenAIRE

    2010-01-01

    Abstract Introduction Purple Glove Syndrome is a devastating complication of intravenous phenytoin administration. Adequate analgesia and preservation of limb movement for physiotherapy are the two essential components of management. Case presentation A 26-year-old Tamil woman from India developed Purple Glove Syndrome after intravenous administration of phenytoin. She was managed conservatively by limb elevation, physiotherapy and oral antibiotics. A 20G intravenous cannula was inserted into...

  13. Assessment of Input-Output Transformation in Purple Passion Fruit Production in Central-Eastern and North-Rift, Kenya

    OpenAIRE

    Ibrahim Macharia; Maina Mwangi

    2013-01-01

    Over the last decade, there has been increasing economic importance of purple passion fruit in Kenya. The primary objective of this study was to assess the input-output transformation process in purple passion fruit production in Central-Eastern and North-Rift Kenya in order to identify avenues for improving and sustaining productivity. Cross-sectional data from 123 multistage sampled farmers was collected using a structured questionnaire, which was subjected to stochastic frontier in STATA 1...

  14. The light intensity under which cells are grown controls the type of peripheral light-harvesting complexes that are assembled in a purple photosynthetic bacterium

    Energy Technology Data Exchange (ETDEWEB)

    Brotosudarmo, Tatas H. P. [Univ. of Glasgow, Scotland (United Kingdom). Inst. of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences; Collins, Aaron M. [Washington Univ., St. Louis, MO (United States). Depts. of Biology and Chemistry; Gall, Andrew [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France). Inst. de Biologie et Technologies de Saclay et CNRS; Roszak, Aleksander W. [Univ. of Glasgow, Scotland (United Kingdom). Dept. of Chemistry, WestChem; Gardiner, Alastair T. [Univ. of Glasgow, Scotland (United Kingdom). Inst. of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences; Blankenship, Robert E. [Washington Univ., St. Louis, MO (United States). Depts. of Biology and Chemistry; Cogdell, Richard J. [Univ. of Glasgow, Scotland (United Kingdom). Inst. of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences

    2011-11-15

    The differing composition of LH2 (peripheral light-harvesting) complexes present in Rhodopseudomonas palustris 2.1.6 have been investigated when cells are grown under progressively decreasing light intensity. Analysis of the absorption spectra reveals there must be more than two types of LH2 complexes present. Purified HL (high-light) and LL (low-light) LH2 complexes have mixed apoprotein compositions. The HL complexes contain PucABa and PucABb apoproteins. The LL complexes contain PucABa, PucABd and PucBb-only apoproteins. This mixed apoprotein composition can explain their resonance Raman spectra.

  15. The light intensity under which cells are grown controls the type of peripheral light-harvesting complexes that are assembled in a purple photosynthetic bacterium.

    Science.gov (United States)

    Brotosudarmo, Tatas H P; Collins, Aaron M; Gall, Andrew; Roszak, Aleksander W; Gardiner, Alastair T; Blankenship, Robert E; Cogdell, Richard J

    2011-11-15

    The differing composition of LH2 (peripheral light-harvesting) complexes present in Rhodopseudomonas palustris 2.1.6 have been investigated when cells are grown under progressively decreasing light intensity. Detailed analysis of their absorption spectra reveals that there must be more than two types of LH2 complexes present. Purified HL (high-light) and LL (low-light) LH2 complexes have mixed apoprotein compositions. The HL complexes contain PucAB(a) and PucAB(b) apoproteins. The LL complexes contain PucAB(a), PucAB(d) and PucB(b)-only apoproteins. This mixed apoprotein composition can explain their resonance Raman spectra. Crystallographic studies and molecular sieve chromatography suggest that both the HL and the LL complexes are nonameric. Furthermore, the electron-density maps do not support the existence of an additional Bchl (bacteriochlorophyll) molecule; rather the density is attributed to the N-termini of the α-polypeptide.

  16. 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

  17. Phenolic composition and antioxidant capacity of yellow and purple-red Ecuadorian cultivars of tree tomato (Solanum betaceum Cav.).

    Science.gov (United States)

    Espin, Susana; Gonzalez-Manzano, Susana; Taco, Verónica; Poveda, Cristina; Ayuda-Durán, Begoña; Gonzalez-Paramas, Ana M; Santos-Buelga, Celestino

    2016-03-01

    Tree tomato fruits from the yellow giant, giant purple and New Zealand purple cultivars, cultivated in Ecuador were analysed for their phenolic composition and antioxidant capacity. Twelve hydroxycinnamoyl derivatives and four anthocyanins (in the purple cultivars) were detected and identified. The hydroxycinnamoyl derivatives mostly derived from caffeic acid, being 3-O-caffeoylquinic acid and rosmarinic acid the majority compounds. Furthermore, various rosmarinic acid glucosides, caffeoyl glucoside, feruloyl glucoside and two ferulic acid dehydrodimers were tentatively identified. The presence of rosmarinic acid is particularly relevant as it constituted a majority phenolic compound in the four studied tree tomato cultivars and it had not been reported previously in this fruit. In the purple cultivars main anthocyanins were pelargonidin 3-O-rutinoside and delphinidin 3-O-rutinoside. The New Zealand purple cultivar was by far the richest sample in both hydroxycinnamates (421.6mg/100g dry pulp) and anthocyanins (168.9mg/100g dry pulp). Antioxidant capacity, as determined by FRAP, ABTS and ORAC assays, followed the same pattern as phenolic contents, with the New Zealand purple cultivar being the one with the highest and the yellow giant cultivar with the lowest values.

  18. A purple-colored 1M mica clay from Silverton, Colorado

    Science.gov (United States)

    Tien, P.-L.

    1969-01-01

    A purple-colored clay of 1M mica polymorph in association with lead-zinc ore was collected from an abandoned mine dump near Silverton, Colorado. Electron micrographs show that the crystallites of the clay are less than 2?? in size and have poorly developed hexagonal outlines. Differential thermal and i.r. absorption analyses indicate similarity with those of muscovite. The structural formula of the 1M mica polymorph is (K1??45Na0??02) (Al3??75Mg0??19) (Si6??90Al1??10) O20(OH)4. The purple color may be related to trace amounts of manganese in the clay. ?? 1969.

  19. Clarification of purple carrot juice: analysis of the fouling mechanisms and evaluation of the juice quality.

    Science.gov (United States)

    Ennouri, Monia; Ben Hassan, Ines; Ben Hassen, Hanen; Lafforgue, Christine; Schmitz, Philippe; Ayadi, Abdelmoneim

    2015-05-01

    Purple carrot juice was clarified by microfiltration. Two modes of filtration, batch concentration and total recycle were tested and the effect of microfiltration process on permeate flux and membrane fouling was studied. Intrinsic membrane resistance was negligible compared with the fouling resistances, which was less than 5 % of total resistance. Determination of membrane hydraulic permeability showed that water cleaning could permit a recovery of about 7 % of initial hydraulic flux. The analysis of color parameters of feed, permeate and concentrate juice during filtration shows that the a* and b* values decrease for the permeate corresponding respectively to changes from green to red and from blue to yellow. The total sugar and reducing sugars increase in permeate and decrease in concentrate. This work showed that it was possible to clarify the purple carrot juice by microfiltration with a real amelioration of the juice appearance.

  20. Preliminary Studies on the Biological Characteristics of Yacon purple blotch%雪莲果紫斑病菌生物学特性初步研究

    Institute of Scientific and Technical Information of China (English)

    李林; 涂勇; 尹蓉; 李江

    2014-01-01

    设定不同培养基、pH值、不同温度和光照条件对雪莲果紫斑病病原菌进行生物学特性的初步研究。结果表明,雪莲果紫斑病菌的最适培养基为PDA,菌丝最适生长温度为24℃,最佳pH值为7~8,光照对菌丝生长影响不大。%The biological characteristics of Yacon purple blotch pathogenic bacteria were studied under the different culture medium, pH values, temperature and illumination. The results showed that the PDA was the optimum culture medium;the pathogenic bacteria could grow well under 24℃and its optimal pH was 7~8;and the illumination affected the hypha growth less.

  1. Cloning and Characterization of a Novel Purple Acid Phosphatase Gene (MtPAP1) from Medicago truncatula Barrel Medic

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A novel purple acid phosphatase gene (MtPAP1) was isolated from the model legume Medicago truncatula Barrel Medic. The cDNA was 1 698 bp in length with an open reading frame (ORF) of 1 398 bp capable of encoding an N-terminal signal peptide of 23 amino acids. The transcripts of MtPAP1 were mainly detected in leaves under high-phosphate conditions, whereas under low-phosphate conditions the transcript level was reduced in leaves and increased in roots, with the strongest hybridization signal detected in roots. A chimeric gene construct fusing MtPAP1 and GFPwas made in which the fusion was driven by the CaMV35S promoter. Transgenlc Arabidopsis plants carrying the chimeric gene constructs showed that the fusion protein was mainly located at the apoplast based on confocal microscopic analysis, showing that MtPAP1 could be secreted to the outside of the cell directed by the signal peptide at the N-terminal. The coding region of MtPAP1 without signal peptide was inserted into the prokaryotic expression vector pET-30a (+) and overexpressed in Escherlchia coll BL21(DE3). The acid phosphatase (APase) proteins extracted from bacterial culture were found largely based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. An enzyme activity assay demonstrated that the APase activity in the transformed bacteria was 3.16-fold higher than that of control. The results imply that MtPAP1 functions to improve phosphorus acquisition in plants under conditions of phosphorus (P) stress.

  2. Photosynthetic machineries in nano-systems.

    Science.gov (United States)

    Nagy, László; Magyar, Melinda; Szabó, Tibor; Hajdu, Kata; Giotta, Livia; Dorogi, Márta; Milano, Francesco

    2014-01-01

    Photosynthetic reaction centres are membrane-spanning proteins, found in several classes of autotroph organisms, where a photoinduced charge separation and stabilization takes place with a quantum efficiency close to unity. The protein remains stable and fully functional also when extracted and purified in detergents thereby biotechnological applications are possible, for example, assembling it in nano-structures or in optoelectronic systems. Several types of bionanocomposite materials have been assembled by using reaction centres and different carrier matrices for different purposes in the field of light energy conversion (e.g., photovoltaics) or biosensing (e.g., for specific detection of pesticides). In this review we will summarize the current status of knowledge, the kinds of applications available and the difficulties to be overcome in the different applications. We will also show possible research directions for the close future in this specific field.

  3. Antihypertensive and antioxidant activity of atomized andean purple corn (Zea mayz L) hydroalcoholic extract in rats

    OpenAIRE

    Arroyo, Jorge; Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Lima, Perú. Químico farmaceútico.; Raez, Ernesto; Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Lima, Perú. Médico patólogo.; Rodríguez, Miguel; Facultad de Odontología, Universidad Nacional Mayor de San Marcos. Lima, Perú. Odontólogo.; Chumpitaz, Víctor; Facultad Odontología, Universidad Nacional Mayor de San Marcos. Lima, Perú. Odontólogo.; Burga, Jonny; Facultad de Odontología, Universidad Nacional Mayor de San Marcos. Lima, Perú. Odontólogo.; De la Cruz, Walter; Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos. Lima, Perú. Médico.; Valencia, José; Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos. Lima, Perú. Químico Farmacéutico.

    2008-01-01

    Objectives. To determine the antihypertensive and antioxidant activity of the atomized hydroalcoholic extract of Zea mays L. (Andean purple corn) in rats with induced hypertension. Material and methods. We used five groups of six Holtzmann rats each, one without hypertension (negative control) and four with hypertension induced by L-NAME: positive control and three groups for the doses of 250, 500 and 1000 mg/kg, respectively. The treatment was carried out orally once a day for 25 days. Th...

  4. Control of yellow and purple nutsedge in elevated CO2 environments with glyphosate and halosulfuron

    Directory of Open Access Journals (Sweden)

    Stephen Christopher Marble

    2015-01-01

    Full Text Available Atmospheric concentrations of carbon dioxide (CO2 have significantly increased over the past century and are expected to continue rising in the future. While elevated levels of CO2 will likely result in higher crop yields, weed growth is also highly likely to increase, which could increase the incidence of herbicide resistant biotypes. An experiment was conducted in 2012 to determine the effects of an elevated CO2 environment on glyphosate and halosulfuron efficacy for postemergence control of purple and yellow nutsedge (Cyperus rotundus L. and C. esculentus L.. Both species of nutsedge where grown in 3.0-L containers under either ambient or elevated (ambient + 200 µmol mol-1 CO2 in open-top field chambers and treated with either 0.5×, 1.0×, or 1.5× of the manufacturer’s labeled rate of halosulfuron, glyphosate, or a tank mix of the two herbicides. The growth of both nutsedge species responded positively to elevated CO2, purple nutsedge had increased shoot and root dry weights and yellow nutsedge had increased shoot, root, and tuber dry weights and counts. Few treatment differences were observed among the herbicides at any of the rates tested. At three weeks following herbicide application, both purple and yellow nutsedge were adequately controlled by both herbicides and combinations at all rates tested, regardless of CO2 concentration. Based on this study, it is likely that predicted future CO2 levels will have little impact on the efficacy of single applications of halosulfuron or glyphosate for control of purple and yellow nutsedge at the growth stages described here, although scenarios demanding more persistent control efforts remain a question.

  5. Control of yellow and purple nutsedge in elevated CO2 environments with glyphosate and halosulfuron.

    Science.gov (United States)

    Marble, S Christopher; Prior, Stephen A; Runion, G Brett; Torbert, H Allen

    2015-01-01

    Atmospheric concentrations of carbon dioxide (CO2) have significantly increased over the past century and are expected to continue rising in the future. While elevated levels of CO2 will likely result in higher crop yields, weed growth is also highly likely to increase, which could increase the incidence of herbicide resistant biotypes. An experiment was conducted in 2012 to determine the effects of an elevated CO2 environment on glyphosate and halosulfuron efficacy for postemergence control of purple and yellow nutsedge (Cyperus rotundus L. and C. esculentus L.). Both species of nutsedge where grown in 3.0-L containers under either ambient or elevated (ambient + 200 μmol mol(-1)) CO2 in open-top field chambers and treated with either 0.5×, 1.0×, or 1.5× of the manufacturer's labeled rate of halosulfuron, glyphosate, or a tank mix of the two herbicides. The growth of both nutsedge species responded positively to elevated CO2, purple nutsedge had increased shoot and root dry weights and yellow nutsedge had increased shoot, root, and tuber dry weights and counts. Few treatment differences were observed among the herbicides at any of the rates tested. At 3 weeks following herbicide application, both purple and yellow nutsedge were adequately controlled by both herbicides and combinations at all rates tested, regardless of CO2 concentration. Based on this study, it is likely that predicted future CO2 levels will have little impact on the efficacy of single applications of halosulfuron or glyphosate for control of purple and yellow nutsedge at the growth stages described here, although scenarios demanding more persistent control efforts remain a question.

  6. Cloning and Characterization of Purple Acid Phosphatase Phytases from Wheat, Barley, Maize and Rice

    DEFF Research Database (Denmark)

    Dionisio, Giuseppe; Madsen, Claus Krogh; Holm, Preben Bach

    2011-01-01

    , it is demonstrated that wheat, barley, maize, and rice all possess purple acid phosphatase (PAP) genes that, expressed in Pichia pastoris, give fully functional phytases (PAPhys) with very similar enzyme kinetics. Preformed wheat PAPhy was localized to the protein crystalloid of the aleurone vacuole. Phylogenetic...... that the PAPhy_a isogene set present in wheat/barley but not in rice/maize is the origin of high phytase activity in mature grains....

  7. Construction and characterization of an azurin analog for the purple copper site in cytochrome c oxidase.

    OpenAIRE

    Hay, M; Richards, J. H.; Lu, Y.

    1996-01-01

    A protein analog of a purple copper center has been constructed from a recombinant blue copper protein (Pseudomonas aeruginosa azurin) by replacing the loop containing the three ligands to the blue copper center with the corresponding loop of the CuA center in cytochrome c oxidase (COX) from Paracoccus denitrificans. The electronic absorption in the UV and visible region (UV-vis) and electron paramagnetic resonance (EPR) spectra of this analog are remarkably similar to those of the native CuA...

  8. Reorganization energy of the CuA center in purple azurin

    DEFF Research Database (Denmark)

    Farver, Ole; Hwang, Hee Jung; Pecht, Israel

    2007-01-01

    shown that lowering the pH from 8.0 to 4.0 results in a similar (~0.4 eV) decrease in reorganization energy for both blue (type 1) and purple (CuA) azurins, even though the reorganization energies of the two different copper centers are different at a given pH. These results suggest that the MV state...

  9. A Study of TheColorPurple from the Lexical Feature of Literary Stylistics

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ying

    2015-01-01

    The Color Purple is one of the most outstanding works of Alice Walker, and more and more people keep close eyes on the novel. In the thesis, it is intended to explore Alice Walker’s writing style from a stylistic perspective, trying to explain how the“meaning”of TheColorPurpleis created through the writer’s linguistic choices and narrative techniques, and to appre⁃ciate the beauty and strength hidden under the surface.

  10. Crystal structures of acid blue and alkaline purple forms of bacteriorhodopsin.

    Science.gov (United States)

    Okumura, Hideo; Murakami, Midori; Kouyama, Tsutomu

    2005-08-19

    Bacteriorhodopsin, a light-driven proton pump found in the purple membrane of Halobacterium salinarum, exhibits purple at neutral pH but its color is sensitive to pH. Here, structures are reported for an acid blue form and an alkaline purple form of wild-type bacteriorhodopsin. When the P622 crystal prepared at pH 5.2 was acidified with sulfuric acid, its color turned to blue with a pKa of 3.5 and a Hill coefficient of 2. Diffraction data at pH 2-5 indicated that the purple-to-blue transition accompanies a large structural change in the proton release channel; i.e. the extracellular half of helix C moves towards helix G, narrowing the proton release channel and expelling a water molecule from a micro-cavity in the vicinity of the retinal Schiff base. In this respect, the acid-induced structural change resembles the structural change observed upon formation of the M intermediate. But, the acid blue form contains a sulfate ion in a site(s) near Arg82 that is created by re-orientations of the carboxyl groups of Glu194 and Glu204, residues comprising the proton release complex. This result suggests that proton uptake by the proton release complex evokes the anion binding, which in turn induces protonation of Asp85, a key residue regulating the absorption spectrum of the chromophore. Interestingly, a pronounced structural change in the proton release complex was also observed at high pH; i.e. re-orientation of Glu194 towards Tyr83 was found to take place at around pH 10. This alkaline transition is suggested to be accompanied by proton release from the proton release complex and responsible for rapid formation of the M intermediate at high pH.

  11. Photosynthetic efficiency in rhizophoracean mangroves with reference to compartmentalization of photosynthetic pigments

    Directory of Open Access Journals (Sweden)

    P. Moorthy

    1999-06-01

    Full Text Available Photosynthetic pigments are localized in protein complexes of chloroplast membranes and their role in photosynthesis has long been established but their efficiency has not been measured in many species. The photosynthetic efficiency of four rhizophoracean mangroves, Rhizophora apiculata, R. mucronata, Bruguiera cylindrica and Ceriops decandra was studied in randomly collected propagules from Pichavaram mangrove forest (southeast coast of India by estimating the concentration of photosynthetic pigments in protein complexes of the thylakoid membrane. Reaction centre chlorophyll (RC-chl was maximum in B. cylindrica and minimum in R. mucronata. Of the total amount of chlorophylls, RC-chl constitutes about 50%. The light harvesting complex chlorophyll (LHC-chl was highest in C. decandra and lowest in R. mucronata. Net photosynthesis was found to be higher in B. cylindrica and lower in R. mucronata with the respective CO2 fixation of 20.52 and 10.83 m mol m-2 s-1. A positive correlation was obtained between RC-chl and net photosynthesis. The stomatal conductance to CO2 influx was also found to be high and low in B. cylindrica and R. mucronata respectively. We refer the chlorophylls present in the reaction centre and light harvesting complex as " membrane bound chlorophyll" and propose to use this as an index for measuring the productivity of mangrove species.

  12. Two Cyanobacterial Photoreceptors Regulate Photosynthetic Light Harvesting by Sensing Teal, Green, Yellow, and Red Light.

    Science.gov (United States)

    Wiltbank, Lisa B; Kehoe, David M

    2016-02-09

    The genomes of many photosynthetic and nonphotosynthetic bacteria encode numerous phytochrome superfamily photoreceptors whose functions and interactions are largely unknown. Cyanobacterial genomes encode particularly large numbers of phytochrome superfamily members called cyanobacteriochromes. These have diverse light color-sensing abilities, and their functions and interactions are just beginning to be understood. One of the best characterized of these functions is the regulation of photosynthetic light-harvesting antenna composition in the cyanobacterium Fremyella diplosiphon by the cyanobacteriochrome RcaE in response to red and green light, a process known as chromatic acclimation. We have identified a new cyanobacteriochrome named DpxA that maximally senses teal (absorption maximum, 494 nm) and yellow (absorption maximum, 568 nm) light and represses the accumulation of a key light-harvesting protein called phycoerythrin, which is also regulated by RcaE during chromatic acclimation. Like RcaE, DpxA is a two-component system kinase, although these two photoreceptors can influence phycoerythrin expression through different signaling pathways. The peak responsiveness of DpxA to teal and yellow light provides highly refined color discrimination in the green spectral region, which provides important wavelengths for photosynthetic light harvesting in cyanobacteria. These results redefine chromatic acclimation in cyanobacteria and demonstrate that cyanobacteriochromes can coordinately impart sophisticated light color sensing across the visible spectrum to regulate important photosynthetic acclimation processes. The large number of cyanobacteriochrome photoreceptors encoded by cyanobacterial genomes suggests that these organisms are capable of extremely complex light color sensing and responsiveness, yet little is known about their functions and interactions. Our work uncovers previously undescribed cooperation between two photoreceptors with very different light

  13. Eukaryotic behaviour of a prokaryotic energy-transducing membrane: fully detached vesicular organelles arise by budding from the Rhodobacter sphaeroides intracytoplasmic photosynthetic membrane.

    Science.gov (United States)

    Niederman, Robert A

    2010-05-01

    A major feature that distinguishes prokaryotic organisms from eukaryotes is their less complex internal structure, in which all membrane-associated functions are thought to be present within a continuous lipid-protein bilayer, rather than with distinct organelles. Contrary to this notion, as described by Tucker and co-workers in this issue of Molecular Microbiology, the application of cryo-electron tomography to the purple bacterium Rhodobacter sphaeroides has demonstrated a heretofore unrecognized ultrastructural complexity within the intracytoplasmic membrane (ICM) housing the photosynthetic apparatus. In addition to distinguishing invaginations of the cytoplasmic membrane (CM) and interconnected vesicular structures still attached to the CM, a eukaryote-like ICM budding process was revealed, which results in the formation of fully detached vesicular structures. These bacterial organelles are able to carry out both the light-harvesting and light-driven energy transduction activities necessary for the cells to assume a photosynthetic lifestyle. Their formation is shown to represent the final stage in a membrane invagination and growth process, originating with small CM indentations, which after cell disruption give rise to a membrane fraction that can be separated from mature ICM vesicles by rate-zone sedimentation.

  14. Structural Characterization of the Novel and Thermal Stable Hydrogenases from the Purple Sulfur Bacteria Thiocapsa Roseopersicina and Lamprobacter Modestohalophilus

    Science.gov (United States)

    2011-08-01

    a molecules of hydrogenase from T. roseopersicina form a ring-shaped hexameric complex with D3 symmetry. It is assumed that the formation of such...Optimization of purification of the hydrogenase from L. modestohalophilus 8 3.4. Optimization of the purification of hydrogenase complex ...activity were pooled and concentrated by ultrafiltration . Methods of preparation of crystal and study of 3D structure of hydrogenase from T

  15. Sensory Quality of Orange, Purple and Yellow Carrots Stored under Controlled Atmosphere

    Directory of Open Access Journals (Sweden)

    Marek GAJEWSKI

    2010-12-01

    Full Text Available The influence of long-term storage of carrot (Daucus carota L. roots under normal and controlled atmosphere (CA on their sensory quality and soluble solids content was investigated. Carrot cultivars of orange (‘Nebula’, purple-orange (‘Purple Haze’ and yellow (‘Mello Yello’ colour of the roots were stored for 6 months at 0-1oC, under controlled atmosphere (CA of gas composition 5% CO2+10% O2, 2% CO2+5% O2, 5% CO2+5% O2 and at normal atmosphere. Sensory quality was evaluated with quantitative descriptive analysis method. Roots of ‘Nebula’ showed the best overall quality under normal atmosphere, although CA resulted in higher firmness and crunchiness. Roots of ‘Purple Haze’ showed the best quality under 5% CO2+5% O2 or 5% CO2+10% O2. Storage in these CA variants resulted in higher sweetness, juiciness, crunchiness and firmness. Roots of ‘Mello Yello’ showed the smallest differences in quality under CA variants. Storage of carrots in CA did not result in off-flavour or off-odour. CA-stored roots showed higher soluble solids content.

  16. Chemical Behavior of Cadmium in Purple Soil as Affected by Surfactants and EDTA

    Institute of Scientific and Technical Information of China (English)

    CHEN Yu-Cheng; XIONG Zhi-Ting; DONG Shan-Yan

    2006-01-01

    A soil batch experiment was conducted to investigate both separate and compound effects of three types of surfactants:anionic dodecylbenzene sulfonic acid sodiumsalt (DBSS), cationic cetyltrimethylammonium bromide (CTAB), and nonionic nonyl phenol polyethyleneoxy ether (TX-100), as well as ethylenediaminetetraacetic acid (EDTA) on cadmium solubility, sorption kinetics, and sorption-desorption behavior in purple soil. The results indicated that both individual application of the three types of surfactants and surfactants combined with EDTA could stimulate Cd extraction from the soil with a general effectiveness ranking of EDTA/TX-100 > EDTA/DBSS > EDTA/CTAB > EDTA > TX-100 >DBSS > CTAB. Further study showed that the compound application of surfactants and EDTA had stronger (P < 0.05)effects on Cd solubility than those added individually. The application of surfactants and EDTA to purple soil (P < 0.05)decreased the proportion of Cd sorbed, while their effectiveness ranking was similar to that of enhanced solubilization. The sorption kinetics of Cd in purple soil was best described by the double-constant equation, while the Freundlich equation gave an excellent fit to the sorption isotherm curves. Therefore, surfactant-enhanced remediation of Cd contaminated soil is feasible and further research should be conducted.

  17. Betalain, Acid Ascorbic, Phenolic Contents and Antioxidant Properties of Purple, Red, Yellow and White Cactus Pears

    Science.gov (United States)

    Sumaya-Martínez, María Teresa; Cruz-Jaime, Sandra; Madrigal-Santillán, Eduardo; García-Paredes, Juan Diego; Cariño-Cortés, Raquel; Cruz-Cansino, Nelly; Valadez-Vega, Carmen; Martinez-Cardenas, Leonardo; Alanís-García, Ernesto

    2011-01-01

    Commercialization of cactus pears based on their antioxidant properties can generate competitive advantages, and these can turn into business opportunities and the development of new products and a high-value ingredient for the food industry. This work evaluated the antioxidant activities (1,1-diphenyl-2-picrylhydrazyl radical-scavenging, protection against oxidation of a β-carotene-linoleic acid emulsion, and iron (II) chelation), the content of total phenolic compounds, ascorbic acid, betacyanin, betaxanthin and the stability of betacyanin pigments in presence of Cu (II)-dependent hydroxyl radicals (OH•), in 18 cultivars of purple, red, yellow and white cactus pear from six Mexican states. Our results indicated that the antiradical activities from yellow and white cactus pear cultivars were not significantly different (p < 0.05) and were lower than the average antiradical activities in red and purple cultivars. The red cactus pear from the state of Zacatecas showed the highest antioxidant activity. The free radical scavenging activity for red cactus pears was significantly correlated (p < 0.05) to the concentration of total phenolic compounds (R2 = 0.90) and ascorbic acid (R2 = 0.86). All 18 cultivars of cactus pears studied showed significant chelating activity of ferrous ions. The red and purple cactus pears showed a great stability when exposed to OH•. PMID:22072899

  18. Betalain, Acid Ascorbic, Phenolic Contents and Antioxidant Properties of Purple, Red, Yellow and White Cactus Pears

    Directory of Open Access Journals (Sweden)

    Leonardo Martinez-Cardenas

    2011-09-01

    Full Text Available Commercialization of cactus pears based on their antioxidant properties can generate competitive advantages, and these can turn into business opportunities and the development of new products and a high-value ingredient for the food industry. This work evaluated the antioxidant activities (1,1-diphenyl-2-picrylhydrazyl radical-scavenging, protection against oxidation of a β-carotene-linoleic acid emulsion, and iron (II chelation, the content of total phenolic compounds, ascorbic acid, betacyanin, betaxanthin and the stability of betacyanin pigments in presence of Cu (II-dependent hydroxyl radicals (OH•, in 18 cultivars of purple, red, yellow and white cactus pear from six Mexican states. Our results indicated that the antiradical activities from yellow and white cactus pear cultivars were not significantly different (p < 0.05 and were lower than the average antiradical activities in red and purple cultivars. The red cactus pear from the state of Zacatecas showed the highest antioxidant activity. The free radical scavenging activity for red cactus pears was significantly correlated (p < 0.05 to the concentration of total phenolic compounds (R2 = 0.90 and ascorbic acid (R2 = 0.86. All 18 cultivars of cactus pears studied showed significant chelating activity of ferrous ions. The red and purple cactus pears showed a great stability when exposed to OH•.

  19. Effect of the Purple Corn Beverage “Chicha Morada” in Composite Resin during Dental Bleaching

    Directory of Open Access Journals (Sweden)

    Eric Dario Acuña

    2016-01-01

    Full Text Available During dental bleaching the staining potential of the surface would increase. This study aims to evaluate the staining susceptibility of one bleached composite resin after the exposure to three different beverages: Peruvian purple corn based beverage (chicha morada, green tea, and distilled water. Thirty disk-shaped specimens of one nanofill composite resin were prepared. The specimens were then divided into six groups (n=5: purple corn (P, purple corn + bleaching (PB, green tea (T, green tea + bleaching (TB, distilled water (W, and distilled water + bleaching (WB. In groups that received bleaching, two sessions of bleaching with 35% hydrogen peroxide were done. Following bleaching, specimens were exposed to each liquid thirty minutes daily. Color was measured with a digital spectrophotometer. For statistical analysis, color measurement differences between the obtained results were used: during bleaching, after bleaching, and during + after bleaching. Two-way ANOVA was used to compare the color changes in the resins of all groups (p3.3.

  20. The development of purple sweet potato bread%紫薯甜面包的研制

    Institute of Scientific and Technical Information of China (English)

    高徐梅; 吕远平

    2011-01-01

    In order to enrich bread varieties and develop more nutritional bread,with the sensory evaluation as the index,the key technical parameters of purple sweet potato bread are determined by orthogonal test as the following:the addition of 100 g purple sweet potato powder and 180 g sugar to each 1 000 g flour,and the dough fermentation time 120 min.The final product has a good color and taste.The product's indexes of purple sweet potato bread are also put forward as well.%为了丰富面包品种、开发更具营养价值的面包,以紫薯甜面包的感官评分为考察指标,通过正交试验确定了紫薯甜面包的关键技术参数:每1 000 g面粉添加100 g紫薯粉、180 g白砂糖,面团发酵时间为120min,所研制的紫薯甜面包具有良好的色泽和口感。同时给出了紫薯甜面包的产品指标。