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Several Isoforms (several + isoform)
Selected AbstractsCytological and enzymatic responses to aluminium stress in root tips of Norway spruce seedlingsNEW PHYTOLOGIST, Issue 3 2004Nina Elisabeth Nagy Summary ,,Aluminium (Al) stress reduces plant growth. However, some species such as Norway spruce (Picea abies) seem to tolerate high Al concentrations. The aim of this study was to investigate characteristics possibly involved in Al tolerance in Norway spruce seedlings. ,,Seedlings (10-d-old) were exposed to Al3+ concentrations of 0.5 and 5 mm for up to 168 h. The effect of Al stress on root growth, cell morphology and Al distribution, callose production, and peroxidase and chitinase activity was analysed. ,,Root growth decreased after 1 d and 2 d with 5 and 0.5 mm Al, respectively. Callose concentration increased strongly after 6 h treatment with 5 mm Al. The activity of many peroxidase and chitinase isoforms decreased after 1,24 h exposure of both treatments. Several isoforms increased after 48,168 h exposure to 5 mm Al. ,,We postulate that, with external Al concentrations 0.5 mm or lower, an increased production above constitutive levels of peroxidase or chitinase is not required for Al tolerance in young Norway spruce seedlings. High constitutive levels of peroxidase and chitinase in this species may be part of this Al tolerance. [source] Immunological characterization of a Blo t 12 isoallergen: identification of immunoglobulin E epitopesCLINICAL & EXPERIMENTAL ALLERGY, Issue 4 2009J. Zakzuk Summary Background Differences in the IgE response to isoallergens could have clinical implications; therefore, its analysis will contribute to the design of better strategies for the diagnosis and treatment of allergic respiratory diseases. Several isoforms have been described from mites but there is no information about the clinical impact of Blomia tropicalis isoallergens. Objective To evaluate the differences in the IgE response against two Blo t 12 isoallergens. Methods The IgE-binding properties of Blo t 12 isoallergens were analysed by ELISA, a skin prick test and ELISA cross-inhibition. Epitope mapping was performed using synthetic overlapping peptides. Fold recognition methods were used to model the chitin-binding domain of the two isoallergens. Results The frequency and strength of the IgE response were greater for Blo t 12.0101 than for Blo t 12.0102. Three IgE-binding areas were identified in Blo t 12.0101; one of them included two residues that are different in Blo t 12.0102. Modelling of the chitin-binding domains of these allergens predicted that they have structural differences that could influence antibody recognition of one of these epitopes. Conclusion In silico structural analysis and immunological characterization of Blo t 12 reveals that allergen polymorphism influences IgE reactivity. Blo t 12.0101 is the most IgE-reactive isoform in Cartagena. The identified IgE epitopes could be mutated to obtain hypoallergenic molecules of potential use for immunotherapy. [source] Conventional protein kinase C isoforms mediate neuroprotection induced by phorbol ester and estrogenJOURNAL OF NEUROCHEMISTRY, Issue 1 2006Myriam Cordey Abstract Rapid signal transduction pathways play a prominent role in mediating neuroprotective actions of estrogen in the CNS. We have previously shown that estrogen-induced neuroprotection of primary cerebrocortical neurons from ,-amyloid peptide (A,) toxicity depends on activation of protein kinase C (PKC). PKC activation with phorbol-12-myristate-13-acetate (PMA) also provides neuroprotection in this paradigm. Because the PKC family includes several isoforms that have opposing roles in regulating cell survival, we sought to identify which PKC isoforms contribute to neuroprotection induced by PMA and estrogen. We detected protein expression of multiple PKC isoforms in primary neuron cultures, including conventional (,, ,I, ,II), novel (,, ,, ,) and atypical (,, ,/,) PKC. Using a panel of isoform-specific peptide inhibitors and activators, we find that novel and atypical PKC isoforms do not participate in the mechanism of either PMA or estrogen neuroprotection. In contrast, a selective peptide activator of conventional PKC isoforms provides dose-dependent neuroprotection against A, toxicity. In addition, peptide inhibitors of conventional, ,I, or ,II PKC isoforms significantly reduce protection afforded by PMA or 17,-estradiol. Taken together, these data provide evidence that conventional PKC isoforms mediate phorbol ester and estrogen neuroprotection of cultured neurons challenged by A, toxicity. [source] Binding of nerve growth factor to its p75 receptor in stressed cells induces selective I,B-, degradation and NF-,B nuclear translocationJOURNAL OF NEUROCHEMISTRY, Issue 2 2001Jose Miguel Cosgaya Nerve growth factor (NGF) regulates the activity of the transcription factor NF-,B (nuclear factor-,B) through its low affinity receptor, p75. In the present study we found that NGF binding to p75 induces nuclear translocation of p65 and increases NF-,B binding activity in a cell line overexpressing p75, but only after the cells have been subjected to a previous stress. Under physiological conditions, in the absence of stress, NGF is unable to alter p65 nuclear levels. Tumor necrosis factor-, (TNF-,) induces a down-regulation of I,B-,, -, and -, both in physiological and in stress, i.e. serum-free, conditions. In contrast, NGF only induces the specific degradation of I,B-, after serum withdrawal, without affecting I,B-, or -, either in the presence or in the absence of stress. I,B-, consists of several isoforms, whose relative abundance is regulated by serum withdrawal. NGF does not target all the I,B-, isoforms with the same potency, being more effective in reducing the levels of the isoforms up-regulated by serum withdrawal. TRAF-6 is expressed at the same level under both physiological and stress conditions. These results indicate that NGF is able to induce NF-,B nuclear translocation by a mechanism that involves specific I,B-, degradation only after the cells have been subjected to a severe stress. [source] Angiostatin K1-3 induces E-selectin via AP1 and Ets1: a mediator for anti-angiogenic action of K1-3JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 11 2008Y.-H. CHEN Summary.,Background:,Angiostatin, a circulating angiogenic inhibitor, is an internal fragment of plasminogen and consists of several isoforms, K1-3 included. We previously showed that K1-3 was the most potent angiostatin to induce E-selectin mRNA expression. The purpose of this study was to identify the mechanism responsible for K1-3-induced E-selectin expression and investigate the role of E-selectin in the anti-angiogenic action of K1-3. Methods and results:,Quantitative real time RT-PCR and Western blotting analyses confirmed a time-dependent increase of E-selectin mRNA and protein induced by K1-3. Subcellular fractionation and immunofluorescence microscopy showed the co-localization of K1-3-induced E-selectin with caveolin 1 (Cav1) in lipid rafts in which E-selectin may behave as a signaling receptor. Promoter-driven reporter assays and site-directed mutagenesis showed that K1-3 induced E-selectin expression via promoter activation and AP1 and Ets-1 binding sites in the proximal E-selectin promoter were required for E-selectin induction. The in vivo binding of both protein complexes to the proximal promoter was confirmed by chromatin immunoprecipitation (ChIP). Although K1-3 induced the activation of ERK1/2 and JNK, only repression of JNK activation attenuated the induction of E-selectin by K1-3. A modulatory role of E-selectin in the anti-angiogenic action of K1-3 was manifested by both overexpression and knockdown of E-selectin followed by cell proliferation assay. Conclusions:,We show that K1-3 induced E-selectin expression via AP1 and Ets-1 binding to the proximal E-selectin promoter (,356/+1), which was positively mediated by JNK activation. Our findings also demonstrate E-selectin as a novel target for the anti-angiogenic therapy. [source] Plasma protein profiling: Unique and stable features of individualsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 15 2005Gary L. Nelsestuen Dr. Abstract Carefully controlled ZipTip extraction of diluted human plasma or serum was combined with MALDI-TOF-MS to produce highly reproducible protein profiles. Components detected included apolipoproteins CI, CII and CIII as well as transthyretin and several isoforms of each protein that are created by glycosylation or other modification and by proteolytic processing. Profiles of healthy individuals all contained the same 15,components. Others were found in plasma from individuals with disease. Profiles were analyzed by peak ratios within the same spectrum. Reproducibility for multiple assays was generally 4 to 10%. Within the healthy population, a given peak ratio occurred with a range of about fourfold. However, peak ratios of multiple samples from the same individual showed a much lower range, typically ±10%. In fact, each individual displayed a personal protein profile that changed very little over time. Because of the stability of protein profiles over time within individuals, these results suggest further studies may discover that certain profile characteristics or changes in an individual's profile may be a sign of current or future disease, even when the altered profile remains within the range for healthy individuals. [source] | |||||||||||||