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Selected AbstractsDifferential CD4+ T-cell memory responses induced by two subsets of human monocyte-derived dendritic cellsIMMUNOLOGY, Issue 3 2007Sandra Bajaña Summary Dendritic cells (DC) are powerful inducers of primary T-cell responses, but their role in secondary responses has not been extensively analysed. Here, we address the role of two DC subsets derived from human CD16+ (16+ mDC) or CD16, (16, mDC) monocytes on the reactivation of memory responses. CD4+ CD45RA, memory T cells were obtained from adult blood donors, and central (TCM) and effector (TEM) memory T cells were isolated by fluorescence-activated cell sorting with anti-CCR7 antibodies. The 16+ mDC and 16, mDC were cocultured with autologous lymphocytes, either unpulsed or loaded with purified protein derivatives of Mycobacterium tuberculosis (PPD) or tetanus toxoid (TT), and were analysed for up to 8 days. Over a range of doses, 16+ mDC drove stronger T-cell proliferative responses against both antigens. Overall, antigen-specific memory cells tended to acquire a phenotype of TEM at later time-points in the culture, whereas cells that had completed fewer cycles of division were similar to TCM. The 16+ mDC induced higher rates of proliferation on both TCM and TEM lymphocytes than 16, mDC. This phenomenon was not related to the ability of both DC to induce CD25 expression on T cells, to lower secretion of interleukin-2, or to raise production of interleukin-10 during T-cell/16, mDC cocultures. The induction of TCM effector capacity in terms of interferon-, production was faster and more pronounced with 16+ mDC, whereas both DC had similar abilities with TEM. In conclusion, these data might reveal new potentials in vaccination protocols with 16+ mDC aimed at inducing strong responses on central memory T cells. [source] The Role of Axial Ligation in Nitrate Reductase: A Model Study by DFT Calculations on the Mechanism of Nitrate ReductionEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 34 2008Kuntal Pal Abstract The reactivity differences of the model anionic complexes [Mo(mnt)2(X)(PPh3)], [mnt2, = 1,2-dicyanoethylenedithiolate; X = SPh (1a), SEt (1b), Cl (1c), Br (1b)] towards oxygen atom transfer from nitrate, which is a key step performed by nitrate reductase, has been investigated by density functional theory calculations. Unlike complexes 1a and 1b, complexes 1c and 1d do not react with nitrate. Thermodynamically, all these complexes have a similar ability to generate the pentacoordinate active state [Mo(mnt)2(X)], by dissociation of PPh3, although the inaccessibility of the dxy orbital in 1c,d and the instability of the corresponding nitrate-bound enzyme substrate (ES) type complex contributes to their failure to reduce nitrate. The nature of the ES complex for 1a,b is described. The variation in the experimental data due to the change of axial ligation from SPh to SEt on the catalytic pathway has also been addressed. The gas-phase and solvent-corrected potential energy surface for the reaction of 1a,b with nitrate are established with fully optimized minima and transition states.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] The Synthesis of Novel Porous Functional Materials for use as Nitrosamine Traps,ADVANCED FUNCTIONAL MATERIALS, Issue 11 2004Y. Xu Abstract Two novel porous nitrosamine traps have been synthesized in order to eliminate carcinogens from the environment. A functional mesoporous material, CuO/SBA-15, has been synthesized by using an in-situ coating method, with the addition of a guest salt to the reaction system to modify the porous materials before the particles of SBA-15 were incubated; the synthesis and modification processes were performed in a single step. The resulting mesoporous composites selectively adsorb N -nitrosopyrrolidine (NPYR), a typical volatile nitrosamine, and are potential cigarette additives that can be used for the removal of nitrosamines from cigarette smoke, thereby protecting public health and the environment. In another reaction, silica gel is modified by being coated with magnesia and then corroded by NaOH solution. The magnesia is dispersed onto the silica by impregnating it with a magnesium acetate solution, followed by calcination. After corrosion of the calcined sample with caustic soda, only the silica particles that are completely covered by magnesia remain. This material exhibits a similar ability to SBA-15 and zeolite NaY in its selective adsorption of NPYR. [source] Phosphorylation of Microtubule-associated Protein SB401 from Solanum berthaultii Regulates Its Effect on MicrotubulesJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 3 2009Bao-Quan Liu Abstract We reported previously that the protein SB401 from Solanum berthaultii binds to and bundles both microtubules and F-actin. In the current study, we investigated the regulation of SB401 activity by its phosphorylation. Our experimental results showed that the phosphorylation of SB401 by casein kinase II (CKII) downregulates the activities of SB401, namely the bundling of microtubules and enhancement of the polymerization of tubulin. However, phosphorylation of SB401 had no observable effect on its bundling of F-actin. Further investigation using extract of potato pollen indicated that a CKII-like kinase may exist in potato pollen. Antibodies against CKII alpha recognized specifically a major band from the pollen extract and the pollen extract was able to phosphorylate the SB401 protein in vitro. The CKII-like kinase showed a similar ability to downregulate the bundling of microtubules. Our experiments demonstrated that phosphorylation plays an important role in the regulation of SB401 activity. We propose that this phosphorylation may regulate the effects of SB401 on microtubules and the actin cytoskeleton. [source] Enhanced proliferation of progenitor cells in the subventricular zone and limited neuronal production in the striatum and neocortex of adult macaque monkeys after global cerebral ischemia,JOURNAL OF NEUROSCIENCE RESEARCH, Issue 6 2005Anton B. Tonchev Abstract Cerebral ischemia in adult rodent models increases the proliferation of endogenous neural progenitor cells residing in the subventricular zone along the anterior horn of the lateral ventricle (SVZa) and induces neurogenesis in the postischemic striatum and cortex. Whether the adult primate brain preserves a similar ability in response to an ischemic insult is uncertain. We used the DNA synthesis indicator bromodeoxyuridine (BrdU) to label newly generated cells in adult macaque monkeys and show here that the proliferation of cells with a progenitor phenotype (double positive for BrdU and the markers Musashi1, Nestin, and ,III-tubulin) in SVZa increased during the second week after a 20-min transient global brain ischemia. Subsequent progenitor migration seemed restricted to the rostral migratory stream toward the olfactory bulb and ischemia increased the proportion of adult-generated cells retaining their location in SVZa with a progenitor phenotype. Despite the lack of evidence for progenitor cell migration toward the postischemic striatum or prefrontal neocortex, a small but sustained proportion of BrdU-labeled cells expressed features of postmitotic neurons (positive for the protein NeuN and the transcription factors Tbr1 and Islet1) in these two regions for at least 79 days after ischemia. Taken together, our data suggest an enhanced neurogenic response in the adult primate telencephalon after a cerebral ischemic insult. © 2005 Wiley-Liss, Inc. [source] Induction of hepatocyte growth factor by fucoidan and fucoidan-derived oligosaccharidesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 4 2008Kazuhiro Fukuta Fucoidan, which is extracted from brown seaweed, is a complex sulphated polysaccharide that is mostly composed of l -fucose and sulphated ester groups. The structural and anionic characteristics of fucoidan are similar to those of heparin. Heparin stimulates production of hepatocyte growth factor (HGF), which has key roles in tissue regeneration. We have shown that fucoidan and fucoidan-derived oligosaccharides have similar ability to stimulate production of HGF as heparin and heparin-derived oligosaccharides. This induction of HGF by heparin or fucoidan and their oligosaccharide derivates occurs primarily at the level of translation, probably via the same mechanism. Fucoidan may thus be useful to protect tissues and organs from various injuries and diseases, via mechanisms involving HGF. [source] Monocyte-derived dendritic cells from HCV-infected patients transduced with an adenovirus expressing NS3 are functional when stimulated with the TLR3 ligand poly(I:C)JOURNAL OF VIRAL HEPATITIS, Issue 11 2008I. Echeverría Summary., Dendritic cells (DC) transfected with an adenovirus encoding hepatitis C virus (HCV) NS3 protein (AdNS3) induce potent antiviral immune responses when used to immunize mice. However, in HCV infected patients, controversial results have been reported regarding the functional properties of monocyte-derived DC (MoDC), a cell population commonly used in DC vaccination protocols. Thus, with the aim of future vaccination studies we decided to characterize MoDC from HCV patients transfected with AdNS3 and stimulated with the TLR3 ligand poly(I:C). Phenotypic and functional properties of these cells were compared with those from MoDC obtained from uninfected individuals. PCR analysis showed that HCV RNA was negative in MoDC from patients after the culture period. Also, phenotypic analysis of these cells showed lower expression of CD80, CD86, and CD40, but similar expression of HLA-DR molecules as compared to MoDC from uninfected individuals. Functional assays of MoDC obtained from patients and controls showed a similar ability to activate allogeneic lymphocytes or to produce IL-12 and IL-10, although lower IFN-, levels were produced by cells from HCV patients after poly(I:C) stimulation. Moreover, both groups of MoDC induced similar profiles of IFN-, and IL-5 after stimulation of allogeneic T-cells. Finally, migration assays did not reveal any difference in their ability to respond to CCL21 chemokine. In conclusion, MoDC from HCV patients are functional after transduction with AdNS3 and stimulation with poly(I:C). These findings suggest that these cells may be useful for therapeutic vaccination in chronic HCV infection. [source] Adhesion of the fish pathogen Flavobacterium psychrophilum to unfertilized eggs of rainbow trout (Oncorhynchus mykiss) and n-hexadecaneLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2001I.N. Vatsos Aims:,The ability of Flavobacterium psychrophilum, the causative agent of rainbow trout fry syndrome (RTFS) in fish, to attach to unfertilized rainbow trout (Oncorhynchus mykiss) eggs and to hydrocarbon n-hexadecane was examined in the present study. Methods and Results:,Five different isolates of Fl. psychrophilum obtained from a variety of origins were compared. The effect of the age of the bacterium and conditions of starvation on the ability of the bacterium to adhere, were also evaluated. Conclusions:,The different isolates were found to exhibit a similar ability to attach to both substrates. Increased surface hydrophobicity and a greater ability to attach to the surface of the eggs were observed with bacteria aged for one month, compared to bacteria cultured in Cytophaga agar for only three days. Significance and Impact of the Study:,These results provide useful information regarding the pathogenicity of RTFS, especially during the initial steps of infection. [source] Identification of a potent immunostimulatory oligodeoxynucleotide from Streptococcus thermophilus lacZANIMAL SCIENCE JOURNAL, Issue 5 2009Takeshi SHIMOSATO ABSTRACT Immunostimulatory sequences of oligodeoxynucleotides (ODNs), such as CpG ODNs, are potent stimulators of innate immunity. Here, we identified a strong immunostimulatory CpG ODN, which we named MsST, from the lac Z gene of Streptococcus (S.) thermophilus ATCC19258, and we evaluated its immune functions. In in vitro studies, MsST had a similar ability as the murine prototype CpG ODN 1555 to induce inflammatory cytokine production and cell proliferation. In mouse splenocytes, MsST increased the number of CD80+CD11c+and CD86+CD11c+ dendritic cells and CD4+CD25+ regulatory T cells. We also analyzed the effects of MsST on the expression of regulatory cytokines by real-time quantitative PCR. MsST was more potent at inducing interleukin-10 expression than the ODN control 1612, indicating that MsST can augment the regulatory T cell response via Toll-like receptor 9, which plays an important role in suppressing T helper type 2 responses. These results suggest that S. thermophilus, whose genes include a strong Immunostimulatory sequence-ODN, is a good candidate for a starter culture to develop new physiologically functional foods and feeds. [source] | |||||||||||||