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981.
Teijón C Olmo R Blanco D Romero A Teijón JM 《Biological trace element research》2006,111(1-3):151-165
The effects of exposure to high doses of lead on reproduction and development have been established, but not so those caused
by low lead doses or the influence that life stage at which contact with the metal takes place might have. The aim of this
work was to study the effects of 200 and 400 ppm lead acetate in drinking water on reproduction and development as well as
on renal and hepatic parameters of rats at different life stages, from gestation to 3 mo postweaning. The results indicate
a dose-dependent effect on reproduction, with variations in the number of births and in pups' weight. Development was mostly
affected at the weaning stage, with hemoglobin levels and erythrocyte numbers significantly decreased. The lead levels in
tissues, blood, urine, and feces along with selected renal and hepatic parameters (blood urea nitrogen, creatinine, alanine
aminotransferase, aspartate aminotransferase, and alkaline phosphatase) were determined. There were histological, blood urea
nitrogen, alanine aminotransferase, and alkaline phosphatase changes in the first month postweaning. After 3 mo, these changes
are no longer evident, possibly because of metabolic adaptation. 相似文献
982.
Dieter Malchow Daniel F Lusche Christina Schlatterer Arturo De Lozanne Annette Müller-Taubenberger 《BMC developmental biology》2006,6(1):31-8
Background
cAMP-induced Ca2+-influx in Dictyostelium is controlled by at least two non-mitochondrial Ca2+-stores: acidic stores and the endoplasmic reticulum (ER). The acidic stores may comprise the contractile vacuole network (CV), the endosomal compartment and acidocalcisomes. Here the role of CV in respect to function as a potential Ca2+-store was investigated. 相似文献983.
Giordano A Avellino R Ferraro P Romano S Corcione N Romano MF 《American journal of physiology. Heart and circulatory physiology》2006,290(6):H2459-H2465
Several lines of evidence support the view that rapamycin inhibits NF-kappaB. TNF-alpha, a potent inducer of NF-kappaB, is released after artery injury (e.g., balloon angioplasty) and plays an important role in inflammation and restenosis. We investigated the effect of rapamycin on NF-kappaB activation and apoptosis in vascular smooth muscle cells (VSMCs) stimulated with TNF-alpha. Using EMSA, we found that TNF-alpha caused NF-kappaB nuclear translocation in VSMCs after 1 h of incubation. Rapamycin inhibited IkappaBalpha degradation, thereby preventing nuclear translocation. Activation of NF-kappaB was accompanied by an increase of Bcl-xL and Bfl-1/A1 proteins, detected by Western blot assay, whereas rapamycin prevented the TNF-alpha-induced enhancement of these antiapoptotic proteins. The extent of apoptosis of VSMCs exposed to TNF-alpha was significantly enhanced by rapamycin. The effect of rapamycin appeared to be independent of the phosphatidylinositol 3-kinase/Akt-protein kinase B survival pathway, because the phosphatidylinositol 3-kinase inhibitor wortmannin neither prevented IkappaBalpha degradation nor increased apoptosis of cells incubated with TNF-alpha. Finally, we demonstrate that the large immunophilin FK-506 binding protein FKBP51 is essential for TNF-alpha-induced NF-kappaB activation in VSMCs. Our findings show that rapamycin inhibits NF-kappaB activation and acts in concert with TNF-alpha in induction of VSMC apoptosis. 相似文献
984.
Heat shock-induced attenuation of hydroxyl radical generation and mitochondrial aconitase activity in cardiac H9c2 cells 总被引:2,自引:0,他引:2
Ilangovan G Venkatakrishnan CD Bratasz A Osinbowale S Cardounel AJ Zweier JL Kuppusamy P 《American journal of physiology. Cell physiology》2006,290(2):C313-C324
A mild heat shock (hyperthermia) protects cells from apoptotic and necrotic deaths by inducing overexpression of various heat shock proteins (Hsps). These proteins, in combination with the activation of the nitric oxide synthase (NOS) enzyme, play important roles in the protection of the myocardium against a variety of diseases. In the present work we report that the generation of potent reactive oxygen species (ROS), namely ·OH in cardiac H9c2 cells, is attenuated by heat shock treatment (2 h at 42°C). Western blot analyses showed that heat shock treatment induced overexpression of Hsp70, Hsp60, and Hsp25. The observed ·OH was found to be derived from the superoxide (O2·) generated by the mitochondria. Whereas the manganese superoxide dismutase (MnSOD) activity was increased in the heat-shocked cells, the mitochondrial aconitase activity was reduced. The mechanism of O2· conversion into ·OH in mitochondria is proposed as follows. The O2· leaked from the electron transport chain, oxidatively damages the mitochondrial aconitase, releasing a free Fe2+. The aconitase-released Fe2+ combines with H2O2 to generate ·OH via a Fenton reaction and the oxidized Fe3+ recombines with the inactivated enzyme after being reduced to Fe2+ by other cellular reductants, turning it over to be active. However, in heat-shocked cells, because of higher MnSOD activity, the excess H2O2 causes irreversible damage to the mitochondrial aconitase enzyme, thus inhibiting its activity. In conclusion, we propose that attenuation of ·OH generation after heat shock treatment might play an important role in reducing the myocardial ischemic injury, observed in heat shock-treated animals. proteins; free radicals; spin trapping; reactive oxygen species 相似文献
985.
Cabo-Bilbao A Spinelli S Sot B Agirre J Mechaly AE Muga A Guérin DM 《Journal of structural biology》2006,155(3):482-492
The chaperonin GroEL adopts a double-ring structure with various modes of allosteric communication. The simultaneous positive intra-ring and negative inter-ring co-operativities alternate the functionality of the folding cavities in both protein rings. Negative inter-ring co-operativity is maintained through different inter-ring interactions, including a salt bridge involving Glu 461. Replacement of this residue by Lys modifies the temperature sensitivity of the substrate-folding activity of this protein, most likely as a result of the loss of inter-ring co-operativity. The crystal structure of the mutant chaperonin GroELE461K has been determined at 3.3A and compared with other structures: the wild-type GroEL, an allosteric defective GroEL double mutant and the GroEL-GroES-(ADP)7 complex. The inter-ring region of the mutant exhibits the following characteristics: (i) no salt-bridge stabilizes the inter-ring interface; (ii) the mutated residue plays a central role in defining the relative ring rotation (of about 22 degrees) around the 7-fold axis; (iii) an increase in the inter-ring distance and solvent accessibility of the inter-ring interface; and (iv) a 2-fold reduction in the stabilization energy of the inter-ring interface, due to the modification of inter-ring interactions. These characteristics explain how the thermal sensitivity of the protein's fundamental properties permits GroEL to distinguish physiological (37 degrees C) from stress (42 degrees C) temperatures. 相似文献
986.
Contractile ring-independent localization of DdINCENP, a protein important for spindle stability and cytokinesis 下载免费PDF全文
Dictyostelium DdINCENP is a chromosomal passenger protein associated with centromeres, the spindle midzone, and poles during mitosis and the cleavage furrow during cytokinesis. Disruption of the single DdINCENP gene revealed important roles for this protein in mitosis and cytokinesis. DdINCENP null cells lack a robust spindle midzone and are hypersensitive to microtubule-depolymerizing drugs, suggesting that their spindles may not be stable. Furthermore DdCP224, a protein homologous to the microtubule-stabilizing protein TOGp/XMAP215, was absent from the spindle midzone of DdINCENP null cells. Overexpression of DdCP224 rescued the weak spindle midzone defect of DdINCENP null cells. Although not required for the localization of the myosin II contractile ring and subsequent formation of a cleavage furrow, DdINCENP is important for the abscission of daughter cells at the end of cytokinesis. Finally, we show that the localization of DdINCENP at the cleavage furrow is modulated by myosin II but it occurs by a mechanism different from that controlling the formation of the contractile ring. 相似文献
987.
988.
Isbaal Ramos Jaime Martín-Benito Ron Finn Laura Breta?a Kerman Aloria Jesús M. Arizmendi Juan Ausió Arturo Muga José M. Valpuesta Adelina Prado 《The Journal of biological chemistry》2010,285(44):33771-33778
Nucleoplasmin (NP) is a pentameric chaperone that regulates the condensation state of chromatin extracting specific basic proteins from sperm chromatin and depositing H2A-H2B histone dimers. It has been proposed that histones could bind to either the lateral or distal face of the pentameric structure. Here, we combine different biochemical and biophysical techniques to show that natural, hyperphosphorylated NP can bind five H2A-H2B dimers and that the amount of bound ligand depends on the overall charge (phosphorylation level) of the chaperone. Three-dimensional reconstruction of NP/H2A-H2B complex carried out by electron microscopy reveals that histones interact with the chaperone distal face. Limited proteolysis and mass spectrometry indicate that the interaction results in protection of the histone fold and most of the H2A and H2B C-terminal tails. This structural information can help to understand the function of NP as a histone chaperone. 相似文献
989.
Beibei Zhai Huiqing Yang Arturo Mancini QingWen He John Antoniou John A. Di Battista 《The Journal of biological chemistry》2010,285(31):23568-23580
990.
Judit Perales-Calvo Arturo Muga Fernando Moro 《The Journal of biological chemistry》2010,285(44):34231-34239
DnaJ from Escherichia coli is a Type I Hsp40 that functions as a cochaperone of DnaK (Hsp70), stimulating its ATPase activity and delivering protein substrates. How DnaJ binds protein substrates is still poorly understood. Here we have studied the role of DnaJ G/F-rich domain in binding of several substrates with different conformational properties (folded, partially (un)folded and unfolded). Using partial proteolysis we find that RepE, a folded substrate, contacts a wide DnaJ area that involves part of the G/F-rich region and Zn-binding domain. Deletion of G/F-rich region hampers binding of native RepE and reduced the affinity for partially (un)folded substrates. However, binding of completely unfolded substrates is independent on the G/F-rich region. These data indicate that DnaJ distinguishes the substrate conformation and is able to adapt the use of the G/F-rich region to form stable substrate complexes. 相似文献