Search results for "Fluorescence"
showing 10 items of 2463 documents
Atšķirīgu barotņu ietekme uz krūts vēža šūnu līniju fenotipiskām pazīmēm
2016
Krūts vēzis ir ļaundabīgs audzējs, kas atšķiras gan viena audzēja ietvaros, gan starp indivīdiem. Lai noskaidrotu pacientam piemērotāko ārstēšanas veidu, tiek noteikti vēža tipi pēc tos veidojošo šūnu morfoloģijas, producētajiem receptoriem, kā arī gēnu ekspresijas. Šūnu kultūrās barotņu sastāvs un citi augšanas apstākļi ietekmē kultivēto šūnu signālprocesus un gēnu ekspresiju. Darbā tika pārbaudīta četru atšķirīgu barotņu ietekme uz krūts vēža līniju (MCF7 un MDA-MB-231) un fibroblastu (HDFa) šūnu līnijas augšanu un fenotipu. Atšķirības tika konstatētas, imūnfluorescenti salīdzinot proteīnu ekspresijas intensitāti, izmantojot augstas caurlaidspējas attēlieguves sistēmu InCell analyzer 2200…
Echolocating Whales and Bats Express the Motor Protein Prestin in the Inner Ear: A Potential Marker for Hearing Loss.
2020
Prestin is an integral membrane motor protein located in outer hair cells of the mammalian cochlea. It is responsible for electromotility and required for cochlear amplification. Although prestin works in a cycle-by-cycle mode up to frequencies of at least 79 kHz, it is not known whether or not prestin is required for the extreme high frequencies used by echolocating species. Cetaceans are known to possess a prestin coding gene. However, the expression and distribution pattern of the protein in the cetacean cochlea has not been determined, and the contribution of prestin to echolocation has not yet been resolved. Here we report the expression of the protein prestin in five species of echolo…
Nitrated Fatty Acids Modulate the Physical Properties of Model Membranes and the Structure of Transmembrane Proteins
2017
Nitrated fatty acids (NO2 -FAs) act as anti-inflammatory signal mediators, albeit the molecular mechanisms behind NO2 -FAs' influence on diverse metabolic and signaling pathways in inflamed tissues are essentially elusive. Here, we combine fluorescence measurements with surface-specific sum frequency generation vibrational spectroscopy and coarse-grained computer simulations to demonstrate that NO2 -FAs alter lipid organization by accumulation at the membrane-water interface. As the function of membrane proteins strongly depends on both, protein structure as well as membrane properties, we consecutively follow the structural dynamics of an integral membrane protein in presence of NO2 -FAs. …
Multi-channel receptors based on thiopyrylium functionalised with macrocyclic receptors for the recognition of transition metal cations and anions.
2010
We report herein the synthesis and characterization of a family of ligands containing different cation binding sites covalently connected to a thiopyrylium signalling reporter. The receptors L1–L6 are able to signal the presence of certain metal cations via three different channels; i.e. electrochemically, fluorogenically and chromogenically. An acetonitrile solution of L1–L6 shows a bright blue colour due to a charge-transfer band in the 575–585 nm region. The colour variation in acetonitrile of L1–L6 in the presence of the metal cations Ag+, Cd2+, Cu2+, Fe3+, Hg2+, Ni2+, Pb2+ and Zn2+ has been studied. A selective hypsochromic shift of the blue band was found for the systems L4-Pb2+ and L…
Properties of a triazolopyridine system as a molecular chemosensor for metal ions, anions, and amino acids.
2006
The characteristics as a chemosensor of the compound 3-methyl-6,8-di(2-pyridyl)-[1,2,3]triazolo[5',1':6,1]pyrido[2,3-]pyrimidine (1) have been analyzed. Interaction with Cu(2+) produces a quenching of the fluorescence, while interaction with Zn(2+) leads to a quenching of the fluorescence followed by a bathochromic shift. The crystal structure of the Zn(1)(H(2)O)(3)(ClO(4))(2) x H(2)O complex shows the coordination of Zn(2+) through the terpyridine moiety. The octahedral site is completed by three water molecules. Interactions of the Zn(2+) complex with the anions sulfate, nitrate, nitrite, and dihydrogenphosphate in ethanol produce hypsochromic shifts and restoration of the fluorescence wh…
Open-chain polyamine ligands bearing an anthracene unit - Chemosensors for logic operations at the molecular level
2001
In this work the absorption and the fluorescence emission properties as well as the protonation sequence of three open chain polyamine ligands of different dimensions bearing an anthracene unit were studied. The protonation and stability constants with Ni2+, Cu2+, Zn2+, and Cd2+ have been determined in 0.15 mol·dm−3 NaCl at 298.1 ± 0.1 K. The values of both protonation and stability constants follow the expected trends according to the number of nitrogen donors, sequence of chelate rings and hydrophilic−hydrophobic balance. Chelation enhancement of the fluorescence emission (CHEF) was observed for some complexes of these ligands with Zn2+ and Cd2+. In contrast the analog complexes containin…
4,4′-bis(dimethylamino)biphenyl containing binding sites. A newfluorescent subunit for cation sensing
2002
The emission behaviour of the 4,4′-bis(dimethylamino)biphenyl subunit covalently attached to aza-crown ethers is studied. Some new ligands have been synthesised in order to test the properties of this new fluorophore. The fluorescence of these new ligands and some other compounds previously described has been studied in acetonitrile in the presence of Ni2+, Cu2+, Zn2+, Hg2+, Pb2+, Cd2+ and also in the presence of some alkali and alkaline-earth cations.
Uranium speciation in plants
2002
The chemical characterization of the radionuclide species is essential for a reliable assessment of the migration of radionuclides and heavy metals into the geological and biological environment on the load pathway soil - plant - animal - human. Only a few is known about the speciation of uranium in plants. Therefore we investigate the change of speciation during the transfer of uranium from initial solution into plant. Various plants (lupins, dandelion e.g.) were grown in an agricultural test field and in the laboratory on contaminated soils (up to concentration of 1g U/kg soil) and as hydroponics in the uranium containing solutions (uranium concentration: 10-5 M - 10-2 M, pH: 3 - 8). For …
Enrichment and activation of smectite-poor clay
2011
A new method of smectite clay enrichment has been developed. The method is based on dispersing clay in a phosphate solution and sequential coagulation. The product of enrichment is characterized with X-ray powder diffraction, wavelength dispersive X-ray fluorescence spectrometry, differential thermal analysis and thermogravimetry. Sorption of methylene blue and hexadecylpyridinium bromide on raw and purified clays was studied.
Chiral cyclohexane based fluorescent chemosensors for enantiomeric discrimination of aspartate
2008
Some new chiral cyclohexyl based fluorescent anion receptors have been synthesized and their absolute configuration has been determined by using circular dichroism (CD). Complexation experiments have been carried out with several dicarboxylates, and stoichiometries and complexation constants for the corresponding complexes have been determined. The chiral discrimination ability of these ligands for chiral dicarboxylates has been studied and the best results have been obtained with TMA aspartate.