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RF Martins V Zina EB Silva MT Rebelo E Figueiredo Z Mendel OS Paulo JC Franco SG Seabra 《Journal of genetics》2012,91(2):e75-e78
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ATP-activated P2X3 receptors of sensory ganglion neurons contribute to pain transduction and are involved in chronic pain signaling. Although highly homologous (97%) in rat and human species, it is unclear whether P2X3 receptors have identical function. Studying human and rat P2X3 receptors expressed in patch-clamped human embryonic kidney (HEK) cells, we investigated the role of non-conserved tyrosine residues in the C-terminal domain (rat tyrosine-393 and human tyrosine-376) as key determinants of receptor function. In comparison with rat P2X3 receptors, human P2X3 receptors were more expressed and produced larger responses with slower desensitization and faster recovery. In general, desensitization was closely related to peak current amplitude for rat and human receptors. Downsizing human receptor expression to the same level of the rat one still yielded larger responses retaining slower desensitization and faster recovery. Mutating phenylalanine-376 into tyrosine in the rat receptor did not change current amplitude; yet, it retarded desensitization onset, demonstrating how this residue was important to functionally link these two receptor states. Conversely, removing tyrosine from position 376 strongly down-regulated human receptor function. The different topology of tyrosine residues in the C-terminal domain has contrasting functional consequences and is sufficient to account for species-specific properties of this pain-transducing channel. 相似文献
135.
Goekint M Bos I Heyman E Meeusen R Michotte Y Sarre S 《Journal of applied physiology (Bethesda, Md. : 1985)》2012,112(4):535-541
Hippocampal brain-derived neurotrophic factor (BDNF) protein is increased with exercise in rats. Monoamines seem to play a role in the regulation of BDNF, and monoamine neurotransmission is known to increase with exercise. The purpose of this study was to examine the influence of acute exercise on monoaminergic neurotransmission and BDNF protein concentrations. Hippocampal microdialysis was performed in rats that were subjected to 60 min of treadmill running at 20 m/min or rest. Two hours postexercise, the rats were killed, and the hippocampus was dissected. In experiments without microdialysis, hippocampus and serum samples were collected immediately after exercise. Exercise induced a twofold increase in hippocampal dopamine release. Noradrenaline and serotonin release were not affected. Hippocampal BDNF levels were not influenced, whether they were measured immediately or 2 h after the exercise protocol. Serum BDNF levels did not change either, but serum BDNF was negatively correlated to peripheral corticosterone concentrations, indicating a possible inhibitory reaction to the stress of running. Sixty minutes of exercise enhances dopamine release in the hippocampus of the rat in vivo. However, this increase is not associated with changes in BDNF protein levels immediately nor 2 h after the acute exercise bout. An increased corticosterone level might be the contributing factor for the absence of changes in BDNF. 相似文献
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Silvia Ligios Pere Anadón Francesca Castorina Carmine D’Amico Daniela Esu Elsa Gliozzi Pierparide Gramigna Marco Mola Giovanni Monegato 《Geobios》2012,45(4):351-367
Late Miocene brackish ostracods and molluscs collected in three Italian basins show noticeable differences in their taxonomic composition, despite their capability of dispersing across wide geographic areas. In the Venetian-Friulian Basin (northern Italy), the upper Tortonian sediments contain oligotypic ostracod assemblages including Hemicyprideis dacica dacica, Hemicytheria pejinovicensis, and Loxoconcha cf. L. josephi and few gastropods referable to Planorbidae and Stenothyroides, which are typical of the central Paratethys. In central Italy, the brackish ostracods and molluscs recovered from upper Tortonian-lower Messinian deposits from four Tuscan basins (Volterra-Radicondoli, Velona, Baccinello-Cinigiano, and Valdelsa) display high affinity at a generic level but strong endemicity at a specific level. At Cessaniti (southern Italy), the upper Tortonian unit contains oligotypic brackish ostracods and molluscs: Mediocytherideis (Sylvestra) posterobursa, Cyprideis ruggierii, Loxoconcha cf. L. biformata, and Zonocypris membranae quadricella characterise the ostracod fauna, while Granulolabium bicinctum and Hydrobia frauenfeldi are the dominant molluscs. The recovered ostracods have a strong affinity with brackish species from central and eastern Palaeo-Mediterranean areas, whereas the molluscs present a Paratethyan origin. Despite the fact that the basins are all brackish and partly coeval, the systematics of these assemblages highlights the absence of common species among the three studied areas. Geochemical analyses (stable isotopes and trace elements) are performed on ostracods, and 87Sr/86Sr ratios are established in molluscs and echinoids. The results suggest brackish environments with different compositions and origins of solutes in the three different areas. The Tuscan basins are characterised by brackish waters, with NaCl-enriched waters coming from aquifers of Triassic evaporite bedrock. The brackish deposits of the Venetian-Friulian Basin and Cessaniti are true marginal marine environments, although the northern basin may have been influenced by both the Paratethyan Sava Basin and the northern portion of the Palaeo-Mediterranean water bodies. 相似文献
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TL Liao AC Lin E Chen TW Huang YM Liu YH Chang JF Lai TL Lauderdale JT Wang SC Chang SF Tsai YT Chen 《Journal of bacteriology》2012,194(19):5454
We report the complete genome sequence of Klebsiella oxytoca E718, a New Delhi metallo-β-lactamase-1 (NDM-1)-producing strain isolated from a renal transplant patient. The genome contains a 6,097,032-bp chromosome and two multidrug resistance plasmids with sizes of 324,906 bp and 110,781 bp. 相似文献
140.
Protein deglycation, a new form of protein repair, involves several enzymes. Fructosamine-3-kinase (FN3K), an enzyme found
in mammals and birds, phosphorylates fructosamines on the third carbon of their sugar moiety, making them unstable and causing
them to detach from proteins. This enzyme acts particularly well on fructose-epsilon-lysine, both in free form and in the
accessible regions of proteins. Mice deficient in FN3K accumulate protein-bound fructosamines and free fructoselysine, indicating
that the deglycation mechanism initiated by FN3K is operative in vivo. Mammals and birds also have an enzyme designated ‘FN3K-related
protein’ (FN3KRP), which shares ≈65% sequence identity with FN3K. Unlike FN3K, FN3KRP does not phosphorylate fructosamines,
but acts on ribulosamines and erythrulosamines. As with FN3K, the third carbon is phosphorylated and this leads to destabilization
of the ketoamines. Experiments with intact erythrocytes indicate that FN3KRP is also a protein-repair enzyme. Its physiological
substrates are most likely formed from ribose 5-phosphate and erythrose 4-phosphate, which give rise to ketoamine 5- or 4-phosphates.
The latter are dephosphorylated by ‘low-molecular-weight protein-tyrosine-phosphatase-A’ (LMW-PTP-A) before FN3KRP transfers
a phosphate on the third carbon. The specificity of FN3K homologues present in plants and bacteria is similar to that of mammalian
FN3KRP, suggesting that deglycation of ribulosamines and/or erythrulosamines is an ancient mechanism. Mammalian cells contain
also a phosphatase acting on fructosamine 6-phosphates, which result from the reaction of proteins with glucose 6-phosphate. 相似文献