Search results for "dye"
showing 10 items of 577 documents
Injection and ultrafast regeneration in dye-sensitized solar cells
2014
Injection of an electron from the excited dye molecule to the semiconductor is the initial charge separation step in dye-sensitized solar cells (DSC's). Though the dynamics of the forward injection process has been widely studied, the results reported so far are controversial, especially for complete DSC's. In this work, the electron injection in titanium dioxide (TiO2) films sensitized with ruthenium bipyridyl dyes N3 and N719 was studied both in neat solvent and in a typical iodide/triiodide (I-/I3 -) DSC electrolyte. Transient absorption (TA) spectroscopy was used to monitor both the formation of the oxidized dye and the arrival of injected electrons to the conduction band of TiO2. Emiss…
N,N′-Disubstituted Indigos as Readily Available Red-Light Photoswitches with Tunable Thermal Half-Lives
2017
Some rare indigo derivatives have been known for a long time to be photochromic upon irradiation with red light, which should be advantageous for many applications. However, the absence of strategies to tune their thermal half-lives by modular molecular design as well as the lack of proper synthetic methods to prepare a variety of such molecules from the parent indigo dye have so far precluded their use. In this work, several synthetic protocols for N-functionalization have been developed, and a variety of N-alkyl and N-aryl indigo derivatives have been prepared. By installation of electron-withdrawing substituents on the N-aryl moieties, the thermal stability of the Z-isomers could be enha…
Functional reconstitution of a proton-translocating system responsive to fusicoccin
1988
Crude fusicoccin binding proteins and a partially purified plasma membrane H+-transporting ATPase (EC 3.6.1.34), both solubilized from maize tissues, were simultaneously inserted into liposomes by the freeze-thaw method. ATP-driven intravesicular acidification in the proteoliposomes, measured by the fluorescence quenching of the dye 9-amino-6-chloro-2-methoxyacridine, markedly increased upon addition of fusicoccin to the reconstituted system. This effect could not be observed when binding sites and ATPase preparations were separately reconstituted into the proteoliposomes, thus demonstrating that fusicoccin binding to its receptor is a prerequisite for ATPase stimulation.
Ethnobotany of dye plants in Southern Italy, Mediterranean Basin: floristic catalog and two centuries of analysis of traditional botanical knowledge …
2020
Abstract Background Since ancient times, man has learned to use plants to obtain natural dyes, but this traditional botanical knowledge (TBK) is eroding. In the late, during, and the early 1800s, there was an increase in research related to dye species, and this allowed the development of industry and economy in rural contexts of Southern Italy. Today, dyes are mainly obtained from synthetic products, and this leads to risks for human health related to pollution. Methods Starting from the literature, three catalogs of the dyeing species (plants, algae, fungi, and lichens) used in the Mediterranean Basin and mainly in Southern Italy have been created. Percentages of parts used and colors ext…
Behavior of plant plasma membranes under hydrostatic pressure as monitored by fluorescent environment-sensitive probes.
2010
International audience; We monitored the behavior of plasma membrane (PM) isolated from tobacco cells (BY-2) under hydrostatic pressures up to 3.5 kbar at 30 °C, by steady-state fluorescence spectroscopy using the newly introduced environment-sensitive probe F2N12S and also Laurdan and di-4-ANEPPDHQ. The consequences of sterol depletion by methyl-β-cyclodextrin were also studied. We found that application of hydrostatic pressure led to a marked decrease of hydration as probed by F2N12S and to an increase of the generalized polarization excitation (GPex) of Laurdan. We observed that the hydration effect of sterol depletion was maximal between 1 and 1.5 kbar but was much less important at hig…
Spatial monitoring of gene activity in extraradical and intraradical developmental stages of arbuscular mycorrhizal fungi by direct fluorescent in si…
2008
International audience; Gene expression profiling based on tissue extracts gives only limited information about genes associated with complex developmental processes such as those implicated in fungal interactions with plant roots during arbuscular mycorrhiza development and function. To overcome this drawback, a direct fluorescent in situ RT-PCR methodology was developed for spatial mapping of gene expression in different presymbiotic and symbiotic structures of an arbuscular mycorrhizal fungus. Transcript detection was optimized by targeting the LSU rRNA gene of Glomus intraradices and monitoring expression of a stearoyl-CoA-desaturase gene that is consistently expressed at high levels in…
Elicitins, proteinaceous elicitors of plant defense, are a new class of sterol carrier proteins
1998
Some phytopathogenic fungi within Phytophthora species are unable to synthesize sterols and therefore must pick them up from the membranes of their host-plant, using an unknown mechanism. These pseudo-fungi secrete elicitins which are small hydrophilic cystein-rich proteins. The results show that elicitins studied interact with dehydroergosterol in the same way, but with some time-dependent differences. Elicitins have one binding site with a similar strong affinity for dehydroergosterol. Using a non-steroid hydrophobic fluorescent probe, we showed that phytosterols are able to similarly bind to elicitins. Moreover, elicitins catalyze sterol transfer between phospholipidic artificial membran…
The Plant Inorganic Pyrophosphatase Does Not Transport K+ in Vacuole Membrane Vesicles Multilabeled with Fluorescent Probes for H+, K+, and Membrane …
1995
Abstract It has been claimed that the inorganic pyrophosphatase (PPase) of the plant vacuolar membrane transports K+ in addition to H+ in intact vacuoles (Davies, J. M., Poole, R. J., Rea, P. A., and Sanders, D.(1992) Proc. Natl. Acad. Sci. U. S. A. 89, 11701-11705). Since this was not confirmed using the purified and reconstituted PPase consisting of a 75-kDa polypeptide (Sato, M. H., Kasahara, M., Ishii, N., Homareda, H., Matsui, H., and Yoshida, M. (1994) J. Biol. Chem. 269, 6725-6728), these authors proposed that K+ transport by the PPase is dependent on its association with other membrane components lost during purification. We have examined the hypothesis of K+ translocation by the PP…
Modelling chemical composition in electric systems - implications to the dynamics of dye-sensitised solar cells
2010
International audience; Classical electromagnetism provides limited means to model electric generators. To extend the classical theory in this respect, additional information on microscopic processes is required. In semiconductor devices and electrochemical generators such information may be obtained by modelling chemical composition. Here we use this approach for the modelling of dye-sensitised solar cells. We simulate the steady-state current-voltage characteristics of such a cell, as well as its transient response. Dynamic simulations show optoelectronic hysteresis in these cells under transient light pulse illumination.
Localization microscopy of DNA in situ using Vybrant(®) DyeCycle™ Violet fluorescent probe: A new approach to study nuclear nanostructure at single m…
2016
Higher order chromatin structure is not only required to compact and spatially arrange long chromatids within a nucleus, but have also important functional roles, including control of gene expression and DNA processing. However, studies of chromatin nanostructures cannot be performed using conventional widefield and confocal microscopy because of the limited optical resolution. Various methods of superresolution microscopy have been described to overcome this difficulty, like structured illumination and single molecule localization microscopy. We report here that the standard DNA dye Vybrant(®) DyeCycle™ Violet can be used to provide single molecule localization microscopy (SMLM) images of …