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561.
Elena V. Bichenkova Seyed E. Sadat-Ebrahimi Amanda N. Wilton Niamh O'Toole Debora S. Marks Kenneth T. Douglas 《Nucleosides, nucleotides & nucleic acids》2013,32(9-11):1651-1665
Abstract Binding data are presented for the interaction with brewer's yeast tRNAPhc of a new structural family of ligands, symmetrical bis-benzimidazoles. In addition specific perturbations in chemical shifts were detected by 1-dimensional NMR spectroscopy at 400 MHz for some imino and aromatic methyl protons of tRNAPhc when the tRNA was titrated with distamycin. Competitive displacement of the benzimidazole by added distamycin was followed fluorescence spectroscopy. 相似文献
562.
2,5-Dialkylthiophenes are found in bitumens and crude oils, and previous studies showed that bacterial metabolism of some with a methyl substituent lead to the formation of 5-methyl-2-thiophenecarboxylic acid, which persisted in the culture medium (Fedorak PM & Peakman TM 1992 Biodegradation 2: 223–236). The objectives of this investigation were to study the further metabolism of this acid, and of two dialkylthiophenes, 2,5-diundecylthiophene and 2-(3,7-dimethyloctyl)-5-methylthiophene. Undefined, oil-degrading mixed cultures were used. 5-Methyl-2-thiophenecarboxylic acid was oxidized to 2,5-thiophenedicarboxylic acid which was identified by gas chromatography-mass spectrometry (GC-MS). This dicarboxylic acid was degraded and supported the growth of a mixed microbial population, and approximately 50% of the sulfur in this substrate was detected as sulfate in the medium at the end of the 15-day incubation time. Mixed cultures were incubated with 2,5-diundecylthiophene or 2-(3,7-dimethyloctyl)-5-methylthiophene as their sole carbon source, and at various times some of these were freezedried and the residues were treated to form methyl esters of any carboxylic acids produced. GC-MS analyses showed the presence of several dicarboxylic acids, indicating that both alkyl groups were oxidized. A small amount of the dimethyl ester of 2,5-thiophenedicarboxylic acid was detected in the culture grown on 2,5-diundecylthiophene, and 37% of the sulfur from this dialkylthiophene was detected as sulfate in the medium after 35 days of incubation. 相似文献
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Satoshi Matsuoka Debora A. Nicoll Zhaoping He Kenneth D. Philipson 《The Journal of general physiology》1997,109(2):273-286
The cardiac sarcolemmal Na+-Ca2+ exchanger is modulated by intrinsic regulatory mechanisms. A
large intracellular loop of the exchanger participates in the regulatory responses. We have proposed (Li, Z., D.A.
Nicoll, A. Collins, D.W. Hilgemann, A.G. Filoteo, J.T. Penniston, J.N. Weiss, J.M. Tomich, and K.D. Philipson.
1991. J. Biol. Chem. 266:1014–1020) that a segment of the large intracellular loop, the endogenous XIP region, has
an autoregulatory role in exchanger function. We now test this hypothesis by mutational analysis of the XIP region. Nine XIP-region mutants were expressed in Xenopus oocytes and all displayed altered regulatory properties.
The major alteration was in a regulatory mechanism known as Na+-dependent inactivation. This inactivation is
manifested as a partial decay in outward Na+-Ca2+ exchange current after application of Na+ to the intracellular
surface of a giant excised patch. Two mutant phenotypes were observed. In group 1 mutants, inactivation was
markedly accelerated; in group 2 mutants, inactivation was completely eliminated. All mutants had normal Na+ affinities. Regulation of the exchanger by nontransported, intracellular Ca2+ was also modified by the XIP-region
mutations. Binding of Ca2+ to the intracellular loop activates exchange activity and also decreases Na+-dependent
inactivation. XIP-region mutants were all still regulated by Ca2+. However, the apparent affinity of the group 1 mutants for regulatory Ca2+ was decreased. The responses of all mutant exchangers to Ca2+ application or removal
were markedly accelerated. Na+-dependent inactivation and regulation by Ca2+ are interrelated and are not completely independent processes. We conclude that the endogenous XIP region is primarily involved in movement
of the exchanger into and out of the Na+-induced inactivated state, but that the XIP region is also involved in regulation by Ca2+. 相似文献
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569.
Uenderson Araujo Barbosa Ivanice Ferreira dos Santos Ana Maria Pinto dos Santos Debora Correia dos Santos Grenivel Mota da Costa 《Biological trace element research》2013,154(3):412-417
The Chapeu-de-couro (Echinodorus macrophyllus (Kunth) Micheli) is a native plant from Brazil, which has been mainly used in medicinal application being a potent antirheumatic and diuretic, in the production of soft drinks, and also in the ornamentation of aquariums. In this paper, the metals and metalloids for the leaves of chapeu-de-couro collected in the Paraguacu River from the city Cachoeira, Bahia State, Brazil, was determined and evaluated using multivariate analysis. The samples were digested using nitric acid and hydrogen peroxide and were analyzed using inductively coupled plasma mass spectrometry. The accuracy of the method was confirmed by analysis of a certified reference material of apple leaves, furnished by National Institute of Standard and Technology. The study involved 15 samples of the Paraguacu River. The results expressed as milligrams of element per kilogram of sample demonstrated that the concentration ranges varied: 1.39–5.27 for chromium, 44.85–165.39 for manganese, 0.55–0.84 for arsenic, 0.01–3.94 for antimony, and 0.18–0.31 for lead. The principal component analysis and hierarchical cluster analysis evidenced that the concentrations of the metals and metalloids varied according with the variations in the water of the Paraguacu. 相似文献
570.
Debora D.S. Vogel Nancy N. Ortiz-Villatoro Leandro de Freitas Flavio Aimbire Fúlvio A. Scorza Regiane Albertini Carla A. Scorza 《Journal of biophotonics》2021,14(1):e202000287
Epilepsy is a yet under-recognized consequence after a stroke and nearly 30% of cases are pharmacoresistant. There is an unmet need for therapeutic interventions during epileptogenesis for better long-term disease outcomes. Transcranial photobiomodulation (PBM) and omega-3 (Ω-3) dietary supplementation are two approaches that have been shown promising neuroprotective effects after brain injuries. Here, we studied the PBM treatment or Ω-3 diet during epileptogenesis in long-term recurrent spontaneous abnormal electrical discharges after stroke. Wistar rats received repetitive 780 nm-laser in the scalp or oral diet with Ω-3 for 2-months after photothrombotic stroke. EEG recordings were performed 60 days after treatment end. PBM but not Ω-3 reduced both electrographic seizure duration and spikes number in the ipsilateral and contralateral cortices and ventral posteromedial thalamic nucleus. Conclusively, PBM reduced epileptiform discharges in stroke-induced epilepsy. Our results suggest the PBM as a therapeutic approach for stroke-induced epileptogenesis to minimize long-term disease outcomes. 相似文献