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81.
Murine sclerodermatous graft-versus-host disease, a model for human scleroderma: cutaneous cytokines, chemokines, and immune cell activation 总被引:10,自引:0,他引:10
Zhang Y McCormick LL Desai SR Wu C Gilliam AC 《Journal of immunology (Baltimore, Md. : 1950)》2002,168(6):3088-3098
Murine sclerodermatous graft-vs-host disease (Scl GVHD) models human scleroderma, with prominent skin thickening, lung fibrosis, and up-regulation of cutaneous collagen mRNA. Fibrosis in Scl GVHD may be driven by infiltrating TGF-beta1-producing mononuclear cells. Here we characterize the origin and types of those cutaneous effector cells, the cytokine and chemokine environments, and the effects of anti-TGF-beta Ab on skin fibrosis, immune cell activation markers, and collagen and cytokine synthesis. Donor cells infiltrating skin in Scl GVHD increase significantly at early time points post-transplantation and are detectable by PCR analysis of Y-chromosome sequences when female mice are transplanted with male cells. Cutaneous monocyte/macrophages and T cells are the most numerous cells in Scl GVHD compared with syngeneic controls. These immune cells up-regulate activation markers (MHC class II I-A(d) molecules and class A scavenger receptors), suggesting Ag presentation by cutaneous macrophages in early fibrosing disease. Early elevated cutaneous mRNA expression of TGF-beta1, but not TGF-beta2 or TGF-beta3, and elevated C-C chemokines macrophage chemoattractant protein-1, macrophage inflammatory protein-1alpha, and RANTES precede subsequent skin and lung fibrosis. Therefore, TGF-beta1-producing donor mononuclear cells may be critical effector cells, and C-C chemokines may play important roles in the initiation of Scl GVHD. Abs to TGF-beta prevent Scl GVHD by effectively blocking the influx of monocyte/macrophages and T cells into skin and by abrogating up-regulation of TGF-beta1, thereby preventing new collagen synthesis. The Scl GVHD model is valuable for testing new interventions in early fibrosing diseases, and chemokines may be new potential targets in scleroderma. 相似文献
82.
Formulation of drugs for administration via the nasal cavity is becoming increasingly common. It is of potential clinical relevance to determine whether intranasal drug administration itself, or exposure to other xenobiotics, can modulate the levels and/or activity of nasal mucosal metabolic enzymes, thereby affecting the metabolism and disposition of the drug. In these studies, we examined changes in several of the major metabolic enzymes in nasal epithelial tissues upon exposure to the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), as well as the impact of these changes on the metabolism of a model intranasally administered drug, lidocaine. Results of these studies show that TCDD can induce multiple metabolic enzymes in the olfactory mucosa and that the pattern of induction in the olfactory mucosa does not necessarily parallel that which occurs in the liver. Further, increases in enzyme levels noted by Western blot analysis were associated with increased activities of several nasal mucosal enzymes as well as with enhanced conversion of lidocaine to its major metabolite, monoethyl glycine xylidide (MEGX). These results demonstrate that environmental exposures can influence the levels and activity of nasal mucosal enzymes and impact the pharmacology of drugs administered via the nasal route. 相似文献
83.
Raja SM Wang B Dantuluri M Desai UR Demeler B Spiegel K Metkar SS Froelich CJ 《The Journal of biological chemistry》2002,277(51):49523-49530
We have recently shown that the physiological mediator of granule-mediated apoptosis is a macromolecular complex of granzymes and perforin complexed with the chondroitin-sulfate proteoglycan, serglycin (Metkar, S. S., Wang, B., Aguilar-Santelises, M., Raja, S. M., Uhlin-Hansen, L., Podack, E., Trapani, J. A., and Froelich, C. J. (2002) Immunity 16, 417-428). We now report our biophysical studies establishing the nature of granzyme B-serglycin (GrB.SG) complex. Dynamic laser light scattering studies establish that SG has a hydrodynamic radius of approximately 140 +/- 23 nm, comparable to some viral particles. Agarose mobility shift gels and surface plasmon resonance (SPR), show that SG binds tightly to GrB and has the capacity to hold 30-60 GrB molecules. SPR studies also indicate equivalent binding affinities (K(d) approximately 0.8 microm), under acidic (granule pH) and neutral isotonic conditions (extra-cytoplasmic pH), for GrB.SG interaction. Finally, characterization of GrB.SG interactions within granules revealed complexes of two distinct molecular sizes, one held approximately 4-8 molecules of GrB, whereas the other contained as many as 32 molecules of GrB or other granule proteins. These studies provide a firm biophysical basis for our earlier reported observations that the proapoptotic granzyme is exocytosed predominantly as a macromolecular complex with SG. 相似文献
84.
Approaches to stabilization of inter-domain recombination in polyketide synthase gene expression plasmids 总被引:1,自引:0,他引:1
Hu Z Desai RP Volchegursky Y Leaf T Woo E Licari P Santi DV Hutchinson CR McDaniel R 《Journal of industrial microbiology & biotechnology》2003,30(3):161-167
Regions of extremely high sequence identity are recurrent in modular polyketide synthase (PKS) genes. Such sequences are
potentially detrimental to the stability of PKS expression plasmids used in the combinatorial biosynthesis of polyketide metabolites.
We present two different solutions for circumventing intra-plasmid recombination within the megalomicin PKS genes in Streptomyces coelicolor. In one example, a synthetic gene was used in which the codon usage was reengineered without affecting the primary amino
acid sequence. The other approach utilized a heterologous subunit complementation strategy to replace one of the problematic
regions. Both methods resulted in PKS complexes capable of 6-deoxyerythronolide B analogue biosynthesis in S. coelicolor CH999, permitting reproducible scale-up to at least 5-l stirred-tank fermentation and a comparison of diketide precursor
incorporation efficiencies between the erythromycin and megalomicin PKSs.
Electronic Publication 相似文献
85.
Progressive restriction in fate potential by neural progenitors during cerebral cortical development 总被引:12,自引:0,他引:12
During early stages of cerebral cortical development, progenitor cells in the ventricular zone are multipotent, producing neurons of many layers over successive cell divisions. The laminar fate of their progeny depends on environmental cues to which the cells respond prior to mitosis. By the end of neurogenesis, however, progenitors are lineally committed to producing upper-layer neurons. Here we assess the laminar fate potential of progenitors at a middle stage of cortical development. The progenitors of layer 4 neurons were first transplanted into older brains in which layer 2/3 was being generated. The transplanted neurons adopted a laminar fate appropriate for the new environment (layer 2/3), revealing that layer 4 progenitors are multipotent. Mid-stage progenitors were then transplanted into a younger environment, in which layer 6 neurons were being generated. The transplanted neurons bypassed layer 6, revealing that layer 4 progenitors have a restricted fate potential and are incompetent to respond to environmental cues that trigger layer 6 production. Instead, the transplanted cells migrated to layer 4, the position typical of their origin, and also to layer 5, a position appropriate for neither the host nor the donor environment. Because layer 5 neurogenesis is complete by the stage that progenitors were removed for transplantation, restrictions in laminar fate potential must lag behind the final production of a cortical layer. These results suggest that a combination of intrinsic and environmental cues controls the competence of cortical progenitor cells to produce neurons of different layers. 相似文献
86.
87.
Moy FJ Desai SA Wang X Noronha EJ Zhou Q Ferrone S Powers R 《The Journal of biological chemistry》2000,275(32):24679-24685
The anti-human leukocyte antigen (HLA) class I monoclonal antibody (mAb) TP25.99 has a unique specificity since it recognizes both a conformational and a linear determinant expressed on the beta(2)-mu-associated and beta(2)-mu-free HLA class I heavy chains, respectively. Previously, we reported the identification of a cyclic and a linear peptide that inhibits mAb TP25.99 binding to the beta(2)-mu-associated and beta(2)-mu-free HLA class I heavy chains (S. A. Desai, X. Wang, E. J. Noronha, Q. Zhou, V. Rebmann, H. Grosse-Wilde, F. J. Moy, R. Powers, and S. Ferrone, submitted for publication). The linear X(19) and cyclic LX-8 peptides contain sequence homologous to residues 239-242, 245, and 246 and to residues 194-198, respectively, of HLA class I heavy chain alpha(3) domain. Analysis by two-dimensional transfer nuclear Overhauser effect spectroscopy of the induced solution structures of the linear X(19) and cyclic LX-8 peptides in the presence of mAb TP25.99 showed that the two peptides adopt a similar structural motif despite the lack of sequence homology. The backbone fold is suggestive of a short helical segment followed by a tight turn, reminiscent of the determinant loop region (residues 194-198) on beta(2)-mu-associated HLA class I heavy chains. The structural similarity between the linear X(19) and cyclic LX-8 peptides and the lack of sequence homology suggests that mAb TP25.99 predominantly recognizes a structural motif instead of a consensus sequence. 相似文献
88.
Desai U Swanson R Bock SC Bjork I Olson ST 《The Journal of biological chemistry》2000,275(25):18976-18984
The contribution of Arg(129) of the serpin, antithrombin, to the mechanism of allosteric activation of the protein by heparin was determined from the effect of mutating this residue to either His or Gln. R129H and R129Q antithrombins bound pentasaccharide and full-length heparins containing the antithrombin recognition sequence with similar large reductions in affinity ranging from 400- to 2500-fold relative to the control serpin, corresponding to a loss of 28-35% of the binding free energy. The salt dependence of pentasaccharide binding showed that the binding defect of the mutant serpin resulted from the loss of approximately 2 ionic interactions, suggesting that Arg(129) binds the pentasaccharide cooperatively with other residues. Rapid kinetic studies showed that the mutation minimally affected the initial low affinity binding of heparin to antithrombin, but greatly affected the subsequent conformational activation of the serpin leading to high affinity heparin binding, although not enough to disfavor activation. Consistent with these findings, the mutant antithrombin was normally activated by heparin for accelerated inhibition of factor Xa and thrombin. These results support an important role for Arg(129) in an induced-fit mechanism of heparin activation of antithrombin wherein conformational activation of the serpin positions Arg(129) and other residues for cooperative interactions with the heparin pentasaccharide so as to lock the serpin in the activated state. 相似文献
89.
Protective effect of L-arginine against lipid peroxidation in goat epididymal spermatozoa 总被引:2,自引:0,他引:2
Srivastava S Desai P Coutinho E Govil G 《Physiological chemistry and physics and medical NMR》2000,32(2):127-135
L-arginine plays an important role in physiology of spermatozoa and is shown to enhance the metabolism of these cells. We report here the effect of L-arginine on membrane lipid peroxidation of goat epididymal spermatozoa. Both natural peroxidation as well as that induced by UV radiation, freezing and oxidizing agents have been studied. Irrespective of the nature of induction of peroxidation, L-arginine reduces the extent of lipid peroxidation in a concentration dependent manner. Both L-arginine and alpha-tocopherol act synergistically in protecting against lipid peroxidation induced by the above methods. Thus, in order to provide protection against lipid peroxidation, L-arginine may be added in media used to preserve spermatozoa. 相似文献
90.
An in vitro method of growing bacteria as a defined nutrient-depleted biofilm is proposed. The medium was defined nutritionally in terms of the quantitative composition and by the total amount of nutrient required to achieve a defined population size. Escherichia coli and Burkholderia cepacia were incubated on a filter support placed on a defined volume of solid medium. The change of biomass of the biofilm population was compared with the change in a planktonic culture. The size of the population in stationary phase was proportional to the concentration of limiting substrate up to 40 μmol cm−2 glucose for E. coli and up to 2·7 × 10−9 mol cm−2 iron for B. cepacia . Escherichia coli growing exponentially had a growth rate of μ = 0·30 h−1 in a biofilm and μ = 0·96 h−1 in planktonic culture. The growth rate, μ, for exponentially growing B. cepacia in a biofilm was 1·12 h−1 and in planktonic culture 0·78 h−1 . This method allows the limitation of the size of a biofilm population to a chosen value. 相似文献