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991.
The effect of different cations on the conformational and morphological properties of the capsular polysaccharide produced by Neisseria meningitidis group A was investigated. Circular dichroism studies showed that the presence of Na+, or Ca2+ ions induced different local conformations of the polysaccharide chain through interactions with the phosphodiester group bridging the saccharide residues in the polymer chain. Atomic force microscopy experiments confirmed that the morphology of the polysaccharide chains was different depending on the nature of the counterion. Ammonium ions were associated with the presence of single polymer chains in an elongated conformation, whereas sodium ions favored the folding of the chains into a globular conformation. The addition of calcium ions produced the aggregation of a limited number of globular polysaccharide chains to form a ‘toroidal-like’ structure. 相似文献
992.
Ornella Spadoni Alessio Crestini Paola Piscopo Lorenzo Malvezzi-Campeggi Irene Carunchio Massimo Pieri Cristina Zona Annamaria Confaloni 《Cellular and molecular neurobiology》2009,29(5):635-641
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease defined by motor neuron loss. Transgenic mouse
model (Tg SOD1G93A) shows pathological features that closely mimic those seen in ALS patients. An hypothetic link between
AD and ALS was suggested by finding an higher amount of amyloid precursor protein (APP) in the spinal cord anterior horn neurons,
and of Aβ peptides in ALS patients skin. In this work, we have investigated the expression of some genes involved in Alzheimer’s
disease, as APP, β- and γ-secretase, in an animal model of ALS, to understand some possible common molecular mechanisms between
these two pathologies. For gene expression analysis, we carried out a quantitative RT-PCR in ALS mice and in transgenic mice
over-expressing human wild-type SOD1 (Tg hSOD1). We found that APP and BACE1 mRNA levels were increased 1.5-fold in cortical
cells of Tg SOD1G93A mice respect to Tg hSOD1, whereas the expression of γ-secretase genes, as PSEN1, PSEN2, Nicastrin, and
APH1a, showed no statistical differences between wild-type and ALS mice. Biochemical analysis carried out by immunostaining
and western blotting, did not show any significant modulation of the protein expression compared to the genes, suggesting
the existence of post-translational mechanisms that modify protein levels. 相似文献
993.
Natalia Buzzi Paola Scodelaro BilbaoRicardo Boland Ana Russo de Boland 《Biochimica et Biophysica Acta (BBA)/General Subjects》2009,1790(12):1651-1659
Background
ATP exerts diverse effects on various cell types via specific purinergic P2Y receptors. Intracellular signaling cascades are the main routes of communication between P2Y receptors and regulatory targets in the cell.Methods and results
We examined the role of ATP in the modulation of ERK1/2, JNK1/2, and p38 MAP kinases (MAPKs) in human colon cancer Caco-2 cells. Immunoblot analysis showed that ATP induces the phosphorylation of MAPKs in a time- and dose-dependent manner, peaking at 5 min at 10 µM ATP. Moreover, ATPγS, UTP, and UDP but not ADP or ADPβS increased phosphorylation of MAPKs, indicating the involvement of, at least, P2Y2/P2Y4 and P2Y6 receptor subtypes. RT–PCR studies and PCR product sequencing supported the expression of P2Y2 and P2Y4 receptors in this cell line. Spectrofluorimetric measurements showed that cell stimulation with ATP induced transient elevations in intracellular calcium concentration. In addition, ATP-induced phosphorylation of MAPKs in Caco-2 cells was dependent on Src family tyrosine kinases, calcium influx, and intracellular Ca2+ release and was partially dependent on the cAMP/PKA and PKC pathways and the EGFR.General significance
These findings provide new molecular basis for further understanding the mechanisms involved in ATP functions, as a signal transducer and activator of MAP kinase cascades, in colon adenocarcinoma Caco-2 cells. 相似文献994.
Modified peptides in anti-cancer vaccines: are we eventually improving anti-tumour immunity? 总被引:1,自引:0,他引:1
Iero M Filipazzi P Castelli C Belli F Valdagni R Parmiani G Patuzzo R Santinami M Rivoltini L 《Cancer immunology, immunotherapy : CII》2009,58(7):1159-1167
The discovery of tumour antigens recognized by T cells and the features of immune responses directed against them has paved
the way to a multitude of clinical studies aimed at boosting anti-tumour T cell immunity as a therapeutic tool for cancer
patients. One of the different strategies explored to ameliorate the immunogenicity of tumour antigens in vaccine protocols
is represented by the use of optimized peptides or altered peptide ligands, whose amino acid sequence has been modified for
improving HLA binding or TCR interaction with respect to native epitopes. However, despite the promising results achieved
with preclinical studies, the clinical efficacy of this approach has not yet met the expectations. Although multiple reasons
could explain the relative failure of altered peptide ligands as more effective cancer vaccines, the possibility that T cells
primed by modified tumour peptides might may be unable to effectively cross-recognize tumour cells has not been sufficiently
addressed. Indeed, the introduction of conservative amino acid substitutions may still produce diverse and unpredictable changes
in the HLA/peptide interface, with consequent modifications of the TCR repertoire that can interact with the complex. This
could lead to the expansion of a broad array of T cells whose TCRs may not necessarily react with equivalent affinity with
the original antigenic epitope. Considering the results presently achieved with this vaccine approach, and the emerging availability
of alternative strategies for boosting anti-tumour immunity, the use of modified tumour peptides could be reconsidered.
This article is a symposium paper from the conference “Immunotherapy—From Basic Research to Clinical Applications”, Symposium
of the Collaborative Research Center (SFB) 685, held in Tübingen, Germany, 6–7 March 2008. 相似文献
995.
Paola Bergamini Antonella Pagnoni Tiziana Franceschetti Roberta Piva 《Journal of inorganic biochemistry》2009,103(6):891-897
The strontium salts Sr(cholate)2, (Compound 1), Sr(dehydrocholate)2, (Compound 2) and Sr3(3-dehydrocholanoyliden-l-tartrate)2, (Compound 3) have been prepared and characterized. The potential anti-osteoporotic activity of these compounds was tested on human primary osteoblasts (hOBs) and human primary osteoclasts (hOCs) in comparison with the bioactivity of strontium ranelate, previously registered as drug in the treatment of post-menopausal osteoporosis. Our results led to the hypothesis that the tested compounds, particularly Compound 2, may have requirements for modulating skeletal tissue regeneration or at least down regulating the loss of bone mass. In fact, all tested compounds have been shown to induce maturation in human primary osteoblasts (hOBs) and apoptosis of human primary osteoclasts (hOCs) at the same time. 相似文献
996.
In Southern Italy, an endemic monotypic genus belonging to family Apiaceae occurs: Petagnaea (P. gussonei), relict of Tertiary flora, belonging to subfamily Saniculoideae. At present, P. gussonei is an endangered species and is included in various lists of species deserving special protection. The genus belongs to scapose hemicryptophytes and shares a sciaphilous habitat (hygrophilous woodland). This study is aimed at doing a complete contribution about the evolutionary history of Petagnaea, using molecular markers as plastidial DNA (cpDNA), nuclear ribosomal DNA (rDNA) and data present in literature. We used nucleotide sequences from four regions of the chloroplast genome (rps16 intron, trnL(UAA) intron, atpB-rbcL intergenic spacer, and partial matK gene) to investigate possible haplotypes in Petagnaea populations. To have an idea of the molecular relationships of all populations of P. gussonei, the internal transcribed spacer (ITS) sequences, already employed in recent studies, were obtained for 18 populations. These sequences in combination with other Saniculoideae ITS sequences available from GenBank have been used for a further phylogenetic analysis. The results agree with the current classification of Saniculoideae in placing P. gussonei in tribe Saniculeae, since P. gussonei is in basal position to Sanicula. According to intraspecific chloroplast DNA diversity, no different haplotypes were detected. In addition to molecular data, morphology, cytology, phytochemistry and conservation status have been considered in the discussion. 相似文献
997.
Paola Venditti Angela Bari Lisa Di Stefano Sergio Di Meo 《Free radical biology & medicine》2009,46(3):360-366
We investigated whether swim training modifies the effect of T3-induced hyperthyroidism on metabolism and oxidative damage in rat muscle. Respiratory capacities, oxidative damage, levels of antioxidants, and susceptibility to oxidative challenge of homogenates were determined. Mitochondrial respiratory capacities, H2O2 release rates, and oxidative damage were also evaluated. T3-treated rats exhibited increases in muscle respiratory capacity, which were associated with enhancements in mitochondrial respiratory capacity and tissue mitochondrial protein content in sedentary and trained animals, respectively. Hormonal treatment induced muscle oxidative damage and GSH depletion. Both effects were reduced by training, which also attenuated tissue susceptibility to oxidative challenge. The changes in single antioxidant levels were slightly related to oxidative damage extent, but the examination of parameters affecting the susceptibility to oxidants indicated that training was associated with greater effectiveness of the muscle antioxidant system. Training also attenuated T3-induced increases in H2O2 production and, therefore, oxidative damage of mitochondria by lowering their content of autoxidizable electron carriers. The above results suggest that moderate training is able to reduce hyperthyroid state-linked tissue oxidative damage, increasing antioxidant protection and decreasing the ROS flow from the mitochondria to the cytoplasmic compartment. 相似文献
998.
Ines Batinić-Haberle Salvatore Cuzzocrea Júlio S. Rebouças Gerardo Ferrer-Sueta Emanuela Mazzon Rosanna Di Paola Rafael Radi Ivan Spasojević Ludmil Benov Daniela Salvemini 《Free radical biology & medicine》2009,46(2):192-201
MnTBAP is often referred to as an SOD mimic in numerous models of oxidative stress. We have recently reported that pure MnTBAP does not dismute superoxide, but commercial or poorly purified samples are able to perform O2·?dismutation with low-to-moderate efficacy via non-innocent Mn-containing impurities. Herein, we show that neither commercial nor pure MnTBAP could substitute for SOD enzyme in a SOD-deficient Escherichia coli model, whereas MnTE-2-PyP-treated SOD-deficient E. coli grew as well as a wild-type strain. This SOD-specific system indicates that MnTBAP does not act as an SOD mimic in vivo. In another model, carrageenan-induced pleurisy in mice, inflammation was evidenced by increased pleural fluid exudate and neutrophil infiltration and activation: these events were blocked by 0.3 mg/kg MnTE-2-PyP and, to a slightly lesser extent, by 10 mg/kg of either MnTBAP. Also, 3-nitrotyrosine formation, an indication of peroxynitrite existence in vivo, was blocked by both compounds; again MnTE-2-PyP was 33-fold more effective. Pleurisy model data indicate that MnTBAP exerts some protective actions in common with MnTE-2-PyP, which are not O2·? related and can be fully rationalized if one considers that the common biological role shared by MnTBAP and MnTE-2-PyP is related to their reduction of peroxynitrite and carbonate radical, the latter arising from ONOOCO2 adduct. The log kcat (O2·?) value for MnTBAP is estimated to be about 3.16, which is ~ 5 and ~ 6 orders of magnitude smaller than the SOD activities of the potent SOD mimic MnTE-2-PyP and Cu,Zn-SOD, respectively. This very low value indicates that MnTBAP is too inefficient at dismuting superoxide to be of any biological impact, which was confirmed in the SOD-deficient E. coli model. The peroxynitrite scavenging ability of MnTBAP, however, is only ~ 2.5 orders of magnitude smaller than that of MnTE-2-PyP and is not significantly affected by the presence of the SOD-active impurities in the commercial MnTBAP sample (log kred (ONOO?) = 5.06 for pure and 4.97 for commercial sample). The reduction of carbonate radical is equally fast with MnTBAP and MnTE-2-PyP. The dose of MnTBAP required to yield oxidative stress protection and block nitrotyrosine formation in the pleurisy model is > 1.5 orders of magnitude higher than that of MnTE-2-PyP, which could be related to the lower ability of MnTBAP to scavenge peroxynitrite. The slightly better protection observed with the commercial MnTBAP sample (relative to the pure MnTBAP) could arise from its impurities, which, by scavenging O2·?, reduce consequently the overall peroxynitrite and secondary ROS/RNS levels. These observations have profound biological repercussions as they may suggest that the effect of MnTBAP observed in numerous studies may conceivably relate to peroxynitrite scavenging. Moreover, provided that pure MnTBAP is unable to dismute superoxide at any significant extent, but is able to partially scavenge peroxynitrite and carbonate radical, this compound may prove valuable in distinguishing ONOO?/CO3·? from O2·? pathways. 相似文献
999.
Donati C Cencetti F De Palma C Rapizzi E Brunelli S Cossu G Clementi E Bruni P 《Cellular signalling》2009,21(2):228-236
Mesoangioblasts are vessel-derived progenitor cells that can be induced to differentiate into different cell types of the mesoderm such as muscle and bone. Here we examined the role of transforming growth factor-beta (TGFbeta), a pleiotropic cytokine that plays a major role in development and specifically induces smooth muscle differentiation of mesoangioblasts, in the regulation of death and survival of these cells. TGFbeta exerts a marked anti-apoptotic action in mesoangioblasts with a mechanism involving regulation of sphingosine kinase 1 (SphK1), one of the isoforms responsible for S1P formation. Treatment with the cytokine efficaciously protected mesoangioblasts from apoptosis induced by serum starvation or staurosporine treatment assessed by various means such as activation of caspase-3, determination of cytoplasmic histone-associated-DNA-fragments and PE-AnnexinV staining. The protective action of TGFbeta from staurosporine-induced apoptosis was strongly reduced when the SphK activity was inhibited by drugs, when SphK1 but not SphK2 was downregulated by specific siRNA and when a SphK1 dominant negative mutant was overexpressed. Staurosporine treatment induced down-regulation of both SphK isoforms and TGFbeta rescued SphK1 but not SphK2 expression. Interestingly, TGFbeta strongly enhanced SphK activity during staurosporine-induced cell death. Both TGFbeta-induced SphK1 up-regulation and TGFbeta anti-apoptotic action were found to be dependent on p42/44 MAPK activation. 相似文献
1000.
The HPLC enantiomeric separation of 29 racemic bridged polycyclic compounds was examined on commercially available Chiralcel OD-H and Chiralpak OT(+) columns. The separations were evaluated under normal-phase mode (hexane containing mobile phase) for Chiralcel OD-H and under normal-phase as well as under reversed-phase mode (pure MeOH, temperature 5 degrees C) for Chiralpak OT(+). Almost all compounds were resolved either on Chiralcel OD-H or on Chiralpak OT(+), in some cases on both. The use of trifluoroacetic acid (TFA), as modifier of the hexanic mobile phase, had a beneficial effect on the enantioseparation of some polar and acidic compounds on Chiralcel OD-H. The influence of small chemical structural modifications of the analytes on the enantioseparation behavior is discussed. A structure-retention relationship has been observed on both stationary phases. This chromatographic evaluation may provide some information about the chiral recognition mechanism: in the case of Chiralcel OD-H, hydrogen bonding, pi-pi and distereoselective repulsive are supposed to be the major analyte-CSP interactions. In the case of Chiralpak OT(+), a reversed-phase enantioseparation could take place through hydrophobic interactions between the aromatic moiety of the analytes and the chiral propeller structure of the CSP. The synthesis of some unknown racemic bromobenzobicyclo[2.2.1] analytes is also described. 相似文献