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https://www.readbyqxmd.com/read/28531352/conformational-complexity-in-the-lh2-antenna-of-the-purple-sulfur-bacterium-allochromatium-vinosum-revealed-by-hole-burning-spectroscopy
#1
Adam Kell, Mahboobe Jassas, Khem Acharya, Kirsty Hacking, Richard J Cogdell, Ryszard J Jankowiak
This work discusses the protein conformational complexity of the B800-850 LH2 complexes from the purple sulfur bacterium Allochromatium vinosum, focusing on the spectral characteristics of the B850 chromophores. Low-temperature B850 absorption and the split B800 band shift blue and red, respectively, at elevated temperatures, revealing isosbestic points. The latter indicates the presence of two (unresolved) conformations of B850 bacteriochlorophylls (BChls), referred to as conformations 1 and 2, and two conformations of B800 BChls, denoted as B800R and B800B...
May 22, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28531164/dual-polarization-observations-of-slowly-varying-solar-emissions-from-a-mobile-x-band-radar
#2
Marco Gabella, Andreas Leuenberger
The radio noise that comes from the Sun has been reported in literature as a reference signal to check the quality of dual-polarization weather radar receivers for the S-band and C-band. In most cases, the focus was on relative calibration: horizontal and vertical polarizations were evaluated versus the reference signal mainly in terms of standard deviation of the difference. This means that the investigated radar receivers were able to reproduce the slowly varying component of the microwave signal emitted by the Sun...
May 22, 2017: Sensors
https://www.readbyqxmd.com/read/28528494/carotenoid-to-bacteriochlorophyll-energy-transfer-in-the-rc-lh1-pufx-complex-from-rhodobacter-sphaeroides-containing-the-extended-conjugation-keto-carotenoid-diketospirilloxanthin
#3
Václav Šlouf, Gürkan Keşan, Radek Litvín, David J K Swainsbury, Elizabeth C Martin, C Neil Hunter, Tomáš Polívka
RC-LH1-PufX complexes from a genetically modified strain of Rhodobacter sphaeroides that accumulates carotenoids with very long conjugation were studied by ultrafast transient absorption spectroscopy. The complexes predominantly bind the carotenoid diketospirilloxanthin, constituting about 75% of the total carotenoids, which has 13 conjugated C=C bonds, and the conjugation is further extended to two terminal keto groups. Excitation of diketospirilloxanthin in the RC-LH1-PufX complex demonstrates fully functional energy transfer from diketospirilloxanthin to BChl a in the LH1 antenna...
May 20, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28526061/photosynthesis-at-the-far-red-region-of-the-spectrum-in-acaryochloris-marina
#4
REVIEW
Syed Lal Badshah, Yahia Mabkhot, Salim S Al-Showiman
Acaryochloris marina is an oxygenic cyanobacterium that utilizes far-red light for photosynthesis. It has an expanded genome, which helps in its adaptability to the environment, where it can survive on low energy photons. Its major light absorbing pigment is chlorophyll d and it has α-carotene as a major carotenoid. Light harvesting antenna includes the external phycobilin binding proteins, which are hexameric rods made of phycocyanin and allophycocyanins, while the small integral membrane bound chlorophyll binding proteins are also present...
May 19, 2017: Biological Research
https://www.readbyqxmd.com/read/28525982/blood-meal-induced-regulation-of-the-chemosensory-gene-repertoire-in-the-southern-house-mosquito
#5
Tanvi Taparia, Rickard Ignell, Sharon Rose Hill
BACKGROUND: The southern house mosquito, Culex quinquefasciatus, is one of the most prevalent vectors of lymphatic filariasis and flavivirus-induced encephalitis. Its vectorial capacity is directly affected by its reproductive feeding behaviors, such as host seeking, blood feeding, resting, and egg laying. In mosquitoes, these gonotrophic behaviors are odor-mediated and regulated following blood feeding. Immediately after a blood meal, female mosquitoes show reduced olfactory responsiveness and flight activity, as they enter a resting state...
May 19, 2017: BMC Genomics
https://www.readbyqxmd.com/read/28523607/carotenoid-to-bacteriochlorophyll-energy-transfer-through-vibronic-coupling-in-lh2-from-phaeosprillum-molischianum
#6
Erling Thyrhaug, Craig N Lincoln, Federico Branchi, Giulio Cerullo, Václav Perlík, František Šanda, Heiko Lokstein, Jürgen Hauer
The peripheral light-harvesting antenna complex (LH2) of purple photosynthetic bacteria is an ideal testing ground for models of structure-function relationships due to its well-determined molecular structure and ultrafast energy deactivation. It has been the target for numerous studies in both theory and ultrafast spectroscopy; nevertheless, certain aspects of the convoluted relaxation network of LH2 lack a satisfactory explanation by conventional theories. For example, the initial carotenoid-to-bacteriochlorophyll energy transfer step necessary on visible light excitation was long considered to follow the Förster mechanism, even though transfer times as short as 40 femtoseconds (fs) have been observed...
May 18, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28520928/attraction-oviposition-preferences-and-olfactory-responses-of-corn-infesting-ulidiidae-diptera-to-various-host-based-substrates
#7
D Owens, G S Nuessly, P E Kendra, T A Colquhoun, D R Seal
Fresh market sweet corn (Zea mays L., convar. saccharata var. rugosa, Poales: Poaceae) ears produced in Florida are damaged by the larvae of Euxesta stigmatias Loew, Euxesta eluta Loew, and Chaetopsis massyla Walker (Diptera: Ulidiidae) that renders ears unmarketable. No standard lure exists for monitoring these pests. Oviposition substrate and attractant bioassays were designed to identify attractive substrates for further semiochemical investigation. Frass from the fall armyworm, Spodoptera frugiperda J.E...
May 18, 2017: Environmental Entomology
https://www.readbyqxmd.com/read/28516180/near-infrared-two-photon-imaging-using-a-bright-cationic-yb-iii-bioprobe-spontaneously-internalized-into-live-cells
#8
Anh Thy Bui, Maryline Beyler, Alexei Grichine, Alain Duperray, Jean-Christophe Mulatier, Yannick Guyot, Chantal Andraud, Raphaël Tripier, Sophie Brasselet, Olivier Maury
An Yb(iii) complex based on a dimethyl cyclen macrocyclic ligand functionalized by charge transfer antennae was prepared. This cationic [YbL3](+) complex is stable and soluble in water and presents interesting photophysical nonlinear properties. It is spontaneously internalized and accumulates in live cells. High quality images have been obtained both in a classical NIR-to-vis configuration and in the more challenging NIR-to-NIR one.
May 18, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28513982/plasmon-enhanced-fluorescence-based-on-porphyrin-peptoid-hybridized-gold-nanoparticle-platform
#9
Younghye Kim, Boyeong Kang, Hyo-Yong Ahn, Jiwon Seo, Ki Tae Nam
A porphyrin-peptoid-hybridized silica-coated gold nanoparticle is developed, which is inspired by the protein-chlorophyll ensemble found in photosynthetic antenna. In the natural antenna, chlorophylls are integrated into dense assemblies that are supported by frameworks of proteins, which ensure optimal pigment arrangement for effective light harvesting. In the subject platform, porphyrins are conjugated to the peptoid helix scaffold in a structurally well-defined alignments and subsequently immobilized on the surface of nanoparticles...
May 17, 2017: Small
https://www.readbyqxmd.com/read/28508446/triboluminescence-of-lanthanide-coordination-polymers-with-face-to-face-arranged-substituents
#10
Yuichi Hirai, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fushimi, Tomohiro Seki, Hajime Ito, Yasuchika Hasegawa
Luminescence upon the grinding of solid materials (triboluminescence, TL) has long been a puzzling phenomenon in natural science and has also attracted attention because of its broad application in optics. It has been generally considered that the TL spectra exhibit similar profiles as those of photoluminescence (PL), although they occur from distinct stimuli. Herein, we describe for the first time a large spectral difference between these two physical phenomena using lanthanide(III) coordination polymers with efficient TL and PL properties...
May 16, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28505112/optimizing-the-readout-of-lanthanide-dota-complexes-for-the-detection-of-ligand-bound-copper-i
#11
Jill R Hanna, Christopher Allan, Charlotte Lawrence, Odile Meyer, Neil D Wilson, Alison N Hulme
The CuAAC 'click' reaction was used to couple alkyne-functionalized lanthanide-DOTA complexes to a range of fluorescent antennae. Screening of the antenna components was aided by comparison of the luminescent output of the resultant sensors using data normalized to account for reaction conversion as assessed by IR. A maximum 82-fold enhanced signal:background luminescence output was achieved using a Eu(III)-DOTA complex coupled to a coumarin-azide, in a reaction which is specific to the presence of copper(I)...
May 14, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28504762/surface-enhanced-infrared-absorption-of-chemisorbed-carbon-monoxide-using-plasmonic-nanoantennas
#12
J Haase, S Bagiante, H Sigg, J A van Bokhoven
We report the enhancement of infrared absorption of chemisorbed carbon monoxide on platinum in the gap of plasmonic nanoantennas. Our method is based on the self-assembled formation of platinum nanoislands on nanoscopic dipole antenna arrays manufactured via electron beam lithography. We employ systematic variations of the plasmonic antenna resonance to precisely couple to the molecular stretch vibration of carbon monoxide adsorbed on the platinum nanoislands. Ultimately, we reach more than 1500-fold infrared absorption enhancements, allowing for an ultrasensitive detection of a monolayer of chemisorbed carbon monoxide...
May 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28504201/cilia-the-sensory-antennae-in-the-eye
#13
REVIEW
Helen May-Simera, Kerstin Nagel-Wolfrum, Uwe Wolfrum
Cilia are hair-like projections found on almost all cells in the human body. Originally believed to function merely in motility, the function of solitary non-motile (primary) cilia was long overlooked. Recent research has demonstrated that primary cilia function as signalling hubs that sense environmental cues and are pivotal for organ development and function, tissue hoemoestasis, and maintenance of human health. Cilia share a common anatomy and their diverse functional features are achieved by evolutionarily conserved functional modules, organized into sub-compartments...
May 11, 2017: Progress in Retinal and Eye Research
https://www.readbyqxmd.com/read/28500716/functional-expression-of-gloeobacter-rhodopsin-in-synechocystis-sp-pcc6803
#14
Que Chen, Jos Arents, Srividya Ganapathy, Willem J de Grip, Klaas J Hellingwerf
Proteorhodopsins are light-driven proton pumps that occur widespread in Nature, where they function predominantly in environments with high incident irradiance. Their maximal absorbance is usually in the blue range, but can be extended into the (far)red range of the electromagnetic spectrum. Because they can be expressed heterologously, they may be exploited in studies aimed at increasing the efficiency of photosynthesis. Here we report further studies toward this goal, by comparing the expression of two different bacterial rhodopsins (Proteorhodopsin and Gloeobacter rhodopsin) in the model cyanobacterium Synechocystis sp...
May 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28499880/photoprotection-strategies-of-the-alga-nannochloropsis-gaditana
#15
Volha U Chukhutsina, Rikard Fristedt, Tomas Morosinotto, Roberta Croce
Nannochloropsis spp. are algae with high potential for biotechnological applications due to their capacity to accumulate lipids. However, little is known about their photosynthetic apparatus and acclimation/photoprotective strategies. In this work, we studied the mechanisms of non-photochemical quenching (NPQ), the fast response to high light stress, in Nannochloropsis gaditana by "locking" the cells in six different states during quenching activation and relaxation. Combining biochemical analysis with time-resolved fluorescence spectroscopy, we correlated each NPQ state with the presence of two well-known NPQ components: de-epoxidized xanthophylls and stress-related antenna proteins (LHCXs)...
May 9, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28498710/charge-induced-force-noise-on-free-falling-test-masses-results-from-lisa-pathfinder
#16
M Armano, H Audley, G Auger, J T Baird, P Binetruy, M Born, D Bortoluzzi, N Brandt, A Bursi, M Caleno, A Cavalleri, A Cesarini, M Cruise, K Danzmann, M de Deus Silva, I Diepholz, R Dolesi, N Dunbar, L Ferraioli, V Ferroni, E D Fitzsimons, R Flatscher, M Freschi, J Gallegos, C García Marirrodriga, R Gerndt, L Gesa, F Gibert, D Giardini, R Giusteri, C Grimani, J Grzymisch, I Harrison, G Heinzel, M Hewitson, D Hollington, M Hueller, J Huesler, H Inchauspé, O Jennrich, P Jetzer, B Johlander, N Karnesis, B Kaune, C J Killow, N Korsakova, I Lloro, L Liu, J P López-Zaragoza, R Maarschalkerweerd, S Madden, D Mance, V Martín, L Martin-Polo, J Martino, F Martin-Porqueras, I Mateos, P W McNamara, J Mendes, L Mendes, A Moroni, M Nofrarias, S Paczkowski, M Perreur-Lloyd, A Petiteau, P Pivato, E Plagnol, P Prat, U Ragnit, J Ramos-Castro, J Reiche, J A Romera Perez, D I Robertson, H Rozemeijer, F Rivas, G Russano, P Sarra, A Schleicher, J Slutsky, C Sopuerta, T J Sumner, D Texier, J I Thorpe, C Trenkel, D Vetrugno, S Vitale, G Wanner, H Ward, P J Wass, D Wealthy, W J Weber, A Wittchen, C Zanoni, T Ziegler, P Zweifel
We report on electrostatic measurements made on board the European Space Agency mission LISA Pathfinder. Detailed measurements of the charge-induced electrostatic forces exerted on free-falling test masses (TMs) inside the capacitive gravitational reference sensor are the first made in a relevant environment for a space-based gravitational wave detector. Employing a combination of charge control and electric-field compensation, we show that the level of charge-induced acceleration noise on a single TM can be maintained at a level close to 1...
April 28, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28498660/a-self-assembled-ruthenium-ii-porphyrin-aluminium-iii-porphyrin-fullerene-triad-for-long-lived-photoinduced-charge-separation
#17
Agnese Amati, Paolo Cavigli, Axel Kahnt, Maria Teresa Indelli, Elisabetta Iengo
A very efficient metal-mediated strategy led, in a single step, to a quantitative construction of a new three-component multi-chromophoric system containing one fullerene monoadduct, one aluminium(III) monopyridylporphyrin, and one ruthenium(II) tetraphenylporphyrin. The Al(III) monopyridylporphyrin component plays the pivotal role in directing the correct self-assembly process, and behaves as the antenna unit for the photoinduced processes of interest. A detailed study of the photophysical behavior of the triad was carried out in different solvents (DCM, THF, Toluene) by stationary and time-resolved emission and absorption spectroscopy in the pico- and nanosecond time domains...
May 12, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28497947/energy-transfer-kinetics-in-photosynthesis-as-an-inspiration-for-improving-organic-solar-cells
#18
Collins Nganou, Gerhard Lackner, Bezu Teschome, M Jamal Deen, Noam Adir, David Pouhe, Doru C Lupascu, Martin Mkandawire
Clues to designing highly efficient organic solar cells may lie in understanding the architecture of light-harvesting systems and exciton energy transfer (EET) processes in very efficient photosynthetic organisms. Here, we compare the kinetics of excitation energy tunnelling from the intact phycobilisome (PBS) light-harvesting antenna system to the reaction center in photosystem II in intact cells of the cyanobacterium Acaryochloris marina with the charge transfer after conversion of photons into photocurrent in vertically aligned carbon nanotube (va-CNT) organic solar cells with poly(3-hexyl)thiophene (P3HT) as the pigment...
May 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28497186/microwave-ablation-of-the-lung-in-a-porcine-model-vessel-diameter-predicts-pulmonary-artery-occlusion
#19
George A Carberry, Elisabetta Nocerino, Mircea M Cristescu, Amanda R Smolock, Fred T Lee, Christopher L Brace
PURPOSE: To determine the size of pulmonary artery (PA) at risk for occlusion during percutaneous microwave ablation and to assess the effect of vessel diameter, number, and patency, on ablation zone volume. MATERIALS AND METHODS: Computed tomography (CT) fluoroscopy-guided percutaneous microwave ablations were performed in 8 pigs under general anesthesia. All ablations were performed at 65 W for 5 min with a single 17-gauge antenna positioned in the central third of the lungs...
May 11, 2017: Cardiovascular and Interventional Radiology
https://www.readbyqxmd.com/read/28492633/rational-molecular-design-enhancing-the-photonic-performance-of-red-emitting-perylene-bisimide-dyes
#20
E Avellanal-Zaballa, G Durán-Sampedro, A Prieto-Castañeda, A R Agarrabeitia, I García-Moreno, I López-Arbeloa, J Bañuelos, M J Ortiz
We report the synthesis of novel multichromophoric organic architectures, where perylene red is decorated with BODIPY and/or hydroxycoumarin dyes acting as light harvesters and energy donors. The computationally-aided photophysical study of these molecular assemblies reveals a broadband absorption which, regardless of the excitation wavelength, leads solely to a bright red-edge emission from perylene bisimide after efficient intramolecular energy transfer hops. The increase of the absorbance of these molecular antennas at key pumping wavelengths enhances the laser action of the commercial perylene red...
May 24, 2017: Physical Chemistry Chemical Physics: PCCP
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