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Naoki Sakashita, Hiroshi C Watanabe, Takuya Ikeda, Hiroshi Ishikita
In the cyanobacterial photosystem II (PSII), the O4-water chain in the D1 and CP43 proteins, a chain of water molecules that are directly H-bonded to O4 of the Mn4Ca cluster, is linked with a channel that connects the protein bulk surface along with a membrane-extrinsic protein subunit, PsbU (O4-PsbU channel). The cyanobacterial PSII structure also shows that the O1 site of the Mn4Ca cluster has a chain of H-bonded water molecules, which is linked with the channel that proceeds toward the bulk surface via PsbU and PsbV (O1-PsbU/V channel)...
February 10, 2017: Photosynthesis Research
Tetsuya Yumoto, Toshiharu Mitsuhashi, Yasuaki Yamakawa, Atsuyoshi Iida, Nobuyuki Nosaka, Kohei Tsukahara, Hiromichi Naito, Atsunori Nakao
BACKGROUND: Cushing's reflex usually results from intracranial hypertension. Although Cushing's sign can implicate severe traumatic brain injury (TBI) in injured patients, no major investigations have been made. The purpose of this study was to assess the predictability of life-threatening brain injury requiring immediate neurosurgical intervention (LT-BI) among trauma patients with Cushing's sign in the prehospital setting. METHODS: This was a retrospective study using data from the Japan Trauma Data Bank from the period of 2010 to 2014...
December 9, 2016: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine
Sidsel B Schmidt, Marta Powikrowska, Ken S Krogholm, Bianca Naumann-Busch, Jan K Schjoerring, Søren Husted, Poul E Jensen, Pai R Pedas
A catalytic manganese (Mn) cluster is required for the oxidation of water in the oxygen-evolving complex (OEC) of photosystem II (PSII) in plants. Despite this essential role of Mn in generating the electrons driving photosynthesis, limited information is available on how Mn deficiency affects PSII functionality. We have here used parameters derived from measurements of fluorescence induction kinetics (OJIP transients), non-photochemical quenching (NPQ) and PSII subunit composition to investigate how latent Mn deficiency changes the photochemistry in two barley genotypes differing in Mn efficiency...
2016: Frontiers in Plant Science
Camilo Fernandez, Robert Hsu, Gary Sander, Azad Hussain, Rupert Barshop, Shengxu Li, Tian Shu, Tao Zhang, Patrycja Galazka, Wei Chen, Lydia Bazzano, Thomas D Giles
OBJECTIVES: This study sought to compare the estimation of central systolic blood pressure (cSBP) obtained by two different noninvasive devices, in addition to its comparisons with measured peripheral systolic blood pressure (pSBP), in a biracial (Black/White) community-based cohort. PARTICIPANTS AND METHODS: Estimations of cSBP by applanation tonometry were obtained in 586 participants of the Bogalusa Heart Study (mean age: 43.5 years; 69% White, 54% women) using two different commonly used instruments: Omron HEM-9000AI and SphygmoCor CPV...
November 29, 2016: Blood Pressure Monitoring
Sergei Baranov, Alice Haddy
Oxygen evolution by photosystem II (PSII) involves activation by Cl(-) ion, which is regulated by extrinsic subunits PsbQ and PsbP. In this study, the kinetics of chloride activation of oxygen evolution was studied in preparations of PSII depleted of the PsbQ and PsbP subunits (NaCl-washed and Na2SO4/pH 7.5-treated) over a pH range from 5.3 to 8.0. At low pH, activation by chloride was followed by inhibition at chloride concentrations >100 mM, whereas at high pH activation continued as the chloride concentration increased above 100 mM...
November 28, 2016: Photosynthesis Research
Amanda Perreault, Susan Richter, Cody Bergman, Melinda Wuest, Frank Wuest
Molecular imaging of programmed cell death (apoptosis) in vivo is an innovative strategy for early assessment of treatment response and treatment efficacy in cancer patients. Externalization of phosphatidylserine (PS) to the cell membrane surface of dying cells makes this phospholipid an attractive molecular target for the development of apoptosis imaging probes. In this study, we have radiolabeled PS-binding 14-mer peptide FNFRLKAGAKIRFG (PSBP-6) with positron-emitter copper-64 ((64)Cu) for PET imaging of apoptosis...
October 3, 2016: Molecular Pharmaceutics
Jia-De Lin, Tsai-Yen Wang, Ting-Shan Mo, Shuan-Yu Huang, Chia-Rong Lee
This work successfully develops a largely-gradient-pitched polymer-stabilized blue phase (PSBP) photonic bandgap (PBG) device with a wide-band spatial tunability in nearly entire visible region within a wide blue phase (BP) temperature range including room temperature. The device is fabricated based on the reverse diffusion of two injected BP-monomer mixtures with a low and a high chiral concentrations and afterwards through UV-curing. This gradient-pitched PSBP can show a rainbow-like reflection appearance in which the peak wavelength of the PBG can be spatially tuned from the blue to the red regions at room temperature...
2016: Scientific Reports
Hongyan Sun, Huaxin Dai, Xiaoyun Wang, Guohui Wang
Selenium can mitigate cadmium toxicity in plants. However, the mechanism of this alleviation has not been fully understood. In the present study, the role of Se in inducing tolerance to Cd stress in cucumber was elucidated. Results showed that Se significantly alleviated Cd-induced growth inhibition, reduced Cd concentration, increased SPAD value and improved photosynthetic performance. Through proteomic analysis by two-dimensional gel electrophoresis (2-DE) coupled with mass spectrometry, 26 protein spots were identified, which were significantly influenced by Cd stress and/or Se application...
November 2016: Ecotoxicology and Environmental Safety
Jana Knoppová, Jianfeng Yu, Peter Konik, Peter J Nixon, Josef Komenda
Although the PSII complex is highly conserved in cyanobacteria and chloroplasts, the PsbU and PsbV subunits stabilizing the oxygen-evolving Mn4CaO5 cluster in cyanobacteria are absent in chloroplasts and have been replaced by the PsbP and PsbQ subunits. There is, however, a distant cyanobacterial homolog of PsbP, termed CyanoP, of unknown function. Here we show that CyanoP plays a role in the early stages of PSII biogenesis in Synechocystis sp. PCC 6803. CyanoP is present in the PSII reaction center assembly complex (RCII) lacking both the CP47 and CP43 modules and binds to the smaller D2 module...
September 2016: Plant & Cell Physiology
Xuepeng Wei, Xiaodong Su, Peng Cao, Xiuying Liu, Wenrui Chang, Mei Li, Xinzheng Zhang, Zhenfeng Liu
During photosynthesis, the plant photosystem II core complex receives excitation energy from the peripheral light-harvesting complex II (LHCII). The pathways along which excitation energy is transferred between them, and their assembly mechanisms, remain to be deciphered through high-resolution structural studies. Here we report the structure of a 1.1-megadalton spinach photosystem II-LHCII supercomplex solved at 3.2 Å resolution through single-particle cryo-electron microscopy. The structure reveals a homodimeric supramolecular system in which each monomer contains 25 protein subunits, 105 chlorophylls, 28 carotenoids and other cofactors...
2, 2016: Nature
(no author information available yet)
No abstract text is available yet for this article.
March 2016: Plant Cell
Yan Lu
Photosystem II (PSII) is a multi-component pigment-protein complex that is responsible for water splitting, oxygen evolution, and plastoquinone reduction. Components of PSII can be classified into core proteins, low-molecular-mass proteins, extrinsic oxygen-evolving complex (OEC) proteins, and light-harvesting complex II proteins. In addition to these PSII subunits, more than 60 auxiliary proteins, enzymes, or components of thylakoid protein trafficking/targeting systems have been discovered to be directly or indirectly involved in de novo assembly and/or the repair and reassembly cycle of PSII...
2016: Frontiers in Plant Science
Kentaro Ifuku, Takumi Noguchi
Photosystem II (PSII), which catalyzes photosynthetic water oxidation, is composed of more than 20 subunits, including membrane-intrinsic and -extrinsic proteins. The PSII extrinsic proteins shield the catalytic Mn4CaO5 cluster from the outside bulk solution and enhance binding of inorganic cofactors, such as Ca(2+) and Cl(-), in the oxygen-evolving center (OEC) of PSII. Among PSII extrinsic proteins, PsbO is commonly found in all oxygenic organisms, while PsbP and PsbQ are specific to higher plants and green algae, and PsbU, PsbV, CyanoQ, and CyanoP exist in cyanobacteria...
2016: Frontiers in Plant Science
Andrej Pavlovič, Tibor Stolárik, Lukáš Nosek, Roman Kouřil, Petr Ilík
Gymnosperms, unlike angiosperms, are able to synthesize chlorophyll and form photosystems in complete darkness. Photosystem I (PSI) formed under such conditions is fully active, but photosystem II (PSII) is present in its latent form with inactive oxygen evolving complex (OEC). In this work we have studied light-induced gradual changes in PSII function in dark-grown cotyledons of Norway spruce (Picea abies) via the measurement of chlorophyll a fluorescence rise, absorption changes at 830 nm, thermoluminescence glow curves (TL) and protein analysis...
June 2016: Biochimica et Biophysica Acta
Taishi Nishimura, Ryo Nagao, Takumi Noguchi, Jon Nield, Fumihiko Sato, Kentaro Ifuku
The PsbP protein, an extrinsic subunit of photosystem II (PSII) in green plants, is known to induce a conformational change around the catalytic Mn4CaO5 cluster securing the binding of Ca(2+) and Cl(-) in PSII. PsbP has multiple interactions with the membrane subunits of PSII, but how these affect the structure and function of PSII requires clarification. Here, we focus on the interactions between the N-terminal residues of PsbP and the α subunit of Cytochrome (Cyt) b559 (PsbE). A key observation was that a peptide fragment formed of the first N-terminal 15 residues of PsbP, 'pN15', was able to convert Cyt b559 into its HP form...
February 18, 2016: Scientific Reports
Johnna L Roose, Laurie K Frankel, Manjula P Mummadisetti, Terry M Bricker
Recent investigations have provided important new insights into the structures and functions of the extrinsic proteins of Photosystem II. This review is an update of the last major review on the extrinsic proteins of Photosystem II (Bricker et al., Biochemistry 31:4623-4628 2012). In this report, we will examine advances in our understanding of the structure and function of these components. These proteins include PsbO, which is uniformly present in all oxygenic organisms, the PsbU, PsbV, CyanoQ, and CyanoP proteins, found in the cyanobacteria, and the PsbP, PsbQ and PsbR proteins, found in the green plant lineage...
April 2016: Planta
Giacomo Pucci, Maria Giovanna Ranalli, Francesca Battista, Giuseppe Schillaci
β-Blockers are less effective than other antihypertensive drug classes in reducing central systolic blood pressure (cSBP) as compared with peripheral SBP (pSBP). Whether this effect is less pronounced with vasodilating β-blockers (VBB) when compared with nonvasodilating β-blockers (NVBB) remains unsettled. We conducted a systematic review and meta-analysis of randomized trials exploring the effects of β-blockers on both pSBP and cSBP in hypertension. We selected 20 studies, for a total of 32 treatment arms (n=21 for NVBB, n=11 for VBB) and 1263 participants (n=962 for NVBB, n=301 for VBB)...
February 2016: Hypertension
Wan Zhao, Pengcheng Yang, Le Kang, Feng Cui
Persistent plant viruses usually depend on insects for their transmission; they cannot be transmitted between plants or through mechanical inoculation. However, the mechanism by which persistent viruses become pathogenic in insect vectors remains unknown. In this study, we used Rice stripe virus (RSV), its insect vector Laodelphax striatellus and host plant (Oryza sativa) to explore how persistent viruses acquire pathogenicity from insect vectors. RSV acquired phytopathogenicity in both the alimentary tract and the salivary gland of L...
April 2016: New Phytologist
Tracey J McGaughey, Emily A Fletcher, Sachin A Shah
BACKGROUND: New evidence suggests that central systolic blood pressure (cSBP) and augmentation index (AI) are superior predictors of adverse cardiovascular outcomes compared to peripheral systolic BP (pSBP). We performed a meta-analysis assessing the impact of antihypertensives on cSBP and AI. METHODS: PubMed, Cochrane Library, and CINAHL were searched until September 2014 to identify eligible articles. A DerSimonian and Laird random-effects model was used to calculate the weighted mean difference (WMD) and its 95% confidence interval (CI)...
April 2016: American Journal of Hypertension
Witchukorn Phuthong, Zubin Huang, Tyler M Wittkopp, Kinga Sznee, Mark L Heinnickel, Jan P Dekker, Raoul N Frese, Fritz B Prinz, Arthur R Grossman
To investigate the dynamics of photosynthetic pigment-protein complexes in vascular plants at high resolution in an aqueous environment, membrane-protruding oxygen-evolving complexes (OECs) associated with photosystem II (PSII) on spinach (Spinacia oleracea) grana membranes were examined using contact mode atomic force microscopy. This study represents, to our knowledge, the first use of atomic force microscopy to distinguish the putative large extrinsic loop of Photosystem II CP47 reaction center protein (CP47) from the putative oxygen-evolving enhancer proteins 1, 2, and 3 (PsbO, PsbP, and PsbQ) and large extrinsic loop of Photosystem II CP43 reaction center protein (CP43) in the PSII-OEC extrinsic domains of grana membranes under conditions resulting in the disordered arrangement of PSII-OEC particles...
October 2015: Plant Physiology
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