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941.
942.
Miguel Arredondo María José Mendiburo Sebastián Flores Steven T. Singleton Michael D. Garrick 《Biometals》2014,27(1):115-123
Divalent Metal Transporter 1 (DMT1) is an apical Fe transporter in the duodenum and is involved in endosomal Fe export. Four protein isoforms have been described for DMT1, two from mRNA with an iron responsive element (IRE) and two from mRNA without it. The sets of two begin in exon 1A or 2. We have characterized copper transport using mouse 2/?IRE DMT1 during regulated ectopic expression. HEK293 cells carrying a TetR:Hyg element were stably transfected with pDEST31 containing a 2/?IRE construct. 64Cu1+ incorporation in doxycycline treated cells exhibited 18.6 and 30.0-fold increases in Cu content, respectively when were exposed to 10 and 100 μM of extracellular Cu. Cu content was ~4-fold above that of parent cells or cells carrying just the vector. 64Cu uptake in transfected cells pre-incubated with 5 μM of Cu-His revealed a Vmax and Km of 11.98 ± 0.52 pmol mg protein?1 min?1 and 2.03 ± 0.03 μM, respectively. Doxycycline-stimulated Cu uptake was linear with time. The rates of apical Cu uptake decreased and transepithelial transport increased when intracellular Cu increased. The optimal pH for Cu transport was 6.5; uptake of Cu was temperature dependent. Silver does not inhibit Cu uptake in cells carrying the vector. In conclusion, Cu uptake in HEK293 cells that over-expressed the 2/?IRE isoform of DMT1 transporter supports our earlier contention that DMT1 transports Cu as Cu1+. 相似文献
943.
Armando Méndez-Garrido Maricarmen Hernández-Rodríguez Rafael Zamorano-Ulloa José Correa-Basurto Jessica Elena Mendieta-Wejebe Daniel Ramírez-Rosales Martha Cecilia Rosales-Hernández 《Neurochemical research》2014,39(11):2093-2104
It is well known that the principal biomolecules involved in Alzheimer’s disease (AD) are acetylcholinesterase (AChE), acetylcholine (ACh) and the amyloid beta peptide of 42 amino acid residues (Aβ42). ACh plays an important role in human memory and learning, but it is susceptible to hydrolysis by AChE, while the aggregation of Aβ42 forms oligomers and fibrils, which form senile plaques in the brain. The Aβ42 oligomers are able to produce hydrogen peroxide (H2O2), which reacts with metals (Fe2+, Cu2+, Cr3+, Zn2+, and Cd2+) present at high concentrations in the brain of AD patients, generating the hydroxyl radical (·OH) via Fenton (FR) and Fenton-like (FLR) reactions. This mechanism generates high levels of free radicals and, hence, oxidative stress, which has been correlated with the generation and progression of AD. Therefore, we have studied in vitro how AChE catalytic activity and ACh levels are affected by the presence of metals (Fe3+, Cu2+, Cr3+, Zn2+, and Cd2+), H2O2 (without Aβ42), and · OH radicals produced from FR and FLR. The results showed that the H2O2 and the metals do not modify the AChE catalytic activity, but the ·OH radical causes a decrease in it. On the other hand, metals, H2O2 and ·OH radicals, increase the ACh hydrolysis. This finding suggests that when H2O2, the metals and the ·OH radicals are present, both, the AChE catalytic activity and ACh levels diminish. Furthermore, in the future it may be interesting to study whether these effects are observed when H2O2 is produced directly from Aβ42. 相似文献
944.
María Sol Gaspe Yael Mariana Provecho Romina Valeria Piccinali Ricardo Esteban Gürtler/ 《Memórias do Instituto Oswaldo Cruz》2015,110(3):310-318
House re-invasion by native triatomines after insecticide-based control campaigns
represents a major threat for Chagas disease vector control. We conducted a
longitudinal intervention study in a rural section (Area III, 407 houses) of Pampa
del Indio, northeastern Argentina, and used wing geometric morphometry to compare
pre-spray and post-spray (re-infestant bugs) Triatoma infestans
populations. The community-wide spraying with pyrethroids reduced the prevalence of
house infestation by T. infestans from 31.9% to < 1% during a
four-year follow-up, unlike our previous studies in the neighbouring Area I. Two
groups of bug collection sites differing in wing shape variables before interventions
(including 221 adults from 11 domiciles) were used as a reference for assigning 44
post-spray adults. Wing shape variables from post-spray, high-density bug colonies
and pre-spray groups were significantly different, suggesting that re-infestant
insects had an external origin. Insects from one house differed strongly in wing
shape variables from all other specimens. A further comparison between insects from
both areas supported the existence of independent re-infestation processes within the
same district. These results point to local heterogeneities in house re-infestation
dynamics and emphasise the need to expand the geographic coverage of vector
surveillance and control operations to the affected region. 相似文献
945.
Marta Mauro-Lizcano Lorena Esteban-Martínez Esther Seco Ana Serrano-Puebla Lucia Garcia-Ledo Cláudia Figueiredo-Pereira Helena L A Vieira Patricia Boya 《Autophagy》2015,11(5):833-843
Mitochondrial autophagy, also known as mitophagy, is an autophagosome-based mitochondrial degradation process that eliminates unwanted or damaged mitochondria after cell stress. Most studies dealing with mitophagy rely on the analysis by fluorescence microscopy of mitochondrial-autophagosome colocalization. However, given the fundamental role of mitophagy in the physiology and pathology of organisms, there is an urgent need for novel quantitative methods with which to study this process. Here, we describe a flow cytometry-based approach to determine mitophagy by using MitoTracker Deep Red, a widely used mitochondria-selective probe. Used in combination with selective inhibitors it may allow for the determination of mitophagy flux. Here, we test the validity of the use of this method in cell lines and in primary cell and tissue cultures. 相似文献
946.
The diversification of neoavian birds is one of the most rapid adaptive radiations of extant organisms. Recent whole-genome sequence analyses have much improved the resolution of the neoavian radiation and suggest concurrence with the Cretaceous-Paleogene (K-Pg) boundary, yet the causes of the remaining genome-level irresolvabilities appear unclear. Here we show that genome-level analyses of 2,118 retrotransposon presence/absence markers converge at a largely consistent Neoaves phylogeny and detect a highly differential temporal prevalence of incomplete lineage sorting (ILS), i.e., the persistence of ancestral genetic variation as polymorphisms during speciation events. We found that ILS-derived incongruences are spread over the genome and involve 35% and 34% of the analyzed loci on the autosomes and the Z chromosome, respectively. Surprisingly, Neoaves diversification comprises three adaptive radiations, an initial near-K-Pg super-radiation with highly discordant phylogenetic signals from near-simultaneous speciation events, followed by two post-K-Pg radiations of core landbirds and core waterbirds with much less pronounced ILS. We provide evidence that, given the extreme level of up to 100% ILS per branch in super-radiations, particularly rapid speciation events may neither resemble a fully bifurcating tree nor are they resolvable as such. As a consequence, their complex demographic history is more accurately represented as local networks within a species tree. 相似文献
947.
Jefferson José da Silva Santos Tereza Magalh?es José Valter Joaquim Silva Junior Andréa Nazaré Monteiro Rangel da Silva Marli Tenório Cordeiro Laura Helena Vega Gonzales Gil 《Memórias do Instituto Oswaldo Cruz》2015,110(5):677-683
Full-length dengue virus (DENV) cDNA clones are an invaluable tool for many studies,
including those on the development of attenuated or chimeric vaccines and on
host-virus interactions. Furthermore, the importance of low passage DENV infectious
clones should be highlighted, as these may harbour critical and unique
strain-specific viral components from field-circulating isolates. The successful
construction of a functional Brazilian low passage DENV serotype 2 full-length clone
through homologous recombination reported here supports the use of a strategy that
has been shown to be highly useful by our group for the development of flavivirus
infectious clones and replicons. 相似文献
948.
949.
Vera Muders Silke Kerruth Víctor A. Lórenz-Fonfría Christian Bamann Joachim Heberle Ramona Schlesinger 《FEBS letters》2014
Channelrhodopsin-1 from Chlamydomonas augustae (CaChR1) is a light-activated cation channel, which is a promising optogenetic tool. We show by resonance Raman spectroscopy and retinal extraction followed by high pressure liquid chromatography (HPLC) that the isomeric ratio of all-trans to 13-cis of solubilized channelrhodopsin-1 is with 70:30 identical to channelrhodopsin-2 from Chlamydomonas reinhardtii (CrChR2). Critical frequency shifts in the retinal vibrations are identified in the Raman spectrum upon transition to the open (conductive P2380) state. Fourier transform infrared spectroscopy (FTIR) spectra indicate different structures of the open states in the two channelrhodopsins as reflected by the amide I bands and the protonation pattern of acidic amino acids. 相似文献
950.
María C. Castro Flavio Francini Juan J. Gagliardino María L. Massa 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014