A protein band of approximately 166 kDa was detected in the soluble fraction of root tips and young leaves of maize seedlings, based on Western blot analysis using antibodies raised against mouse macrophage nitric oxide synthase (NOS) and rabbit brain NOS. NOS activity was present in these soluble fractions, as determined by L-[U-IR C]citrulline synthesis from L-[U-IR C]arginine. Immunofluorescence showed that the maize NOS protein is present in the cytosol of cells in the division zone and is translocated into the nucleus in cells in the elongation zone of maize root tips. These results indicate the existence of a NOS enzyme in maize tissues, with the localization of this protein depending on the phase of cell growth.z 1999 Federation of European Biochemical Societies.
Inflammatory bowel diseases (IBD) are characterized by chronic inflammation of the intestinal tract associated with an imbalance of the intestinal microbiota. Crohn's disease (CD) and ulcerative colitis (UC) are the most widely known types of IBD and have been the focus of attention due to their increasing incidence. Recent studies have pointed out genes associated with IBD susceptibility that, together with environment factors, may contribute to the outcome of the disease. In ulcerative colitis, there are several therapies available, depending on the stage of the disease. Aminosalicylates, corticosteroids, and cyclosporine are used to treat mild, moderate, and severe disease, respectively. In Crohn's disease, drug choices are dependent on both location and behavior of the disease. Nowadays, advances in treatments for IBD have included biological therapies, based mainly on monoclonal antibodies or fusion proteins, such as anti-TNF drugs. Notwithstanding the high cost involved, these biological therapies show a high index of remission, enabling a significant reduction in cases of surgery and hospitalization. Furthermore, migration inhibitors and new cytokine blockers are also a promising alternative for treating patients with IBD. In this review, an analysis of literature data on biological treatments for IBD is approached, with the main focus on therapies based on emerging recombinant biomolecules.
Yacon (Smallanthus sonchifolius) is an Andean tuberous root that is regarded as a functional food given that it contains fructooligosaccharides (FOS), inulin and phenolic compounds. The consumption of FOS and inulin improves the growth of bifidobacteria in the colon, enhances mineral absorption and gastrointestinal metabolism and plays a role in the regulation of serum cholesterol. Furthermore, the literature reports that the consumption of these prebiotics promotes a positive modulation of the immune system, improving resistance to infections and allergic reactions. Certain studies have demonstrated the potential of yacon as an alternative food source for those patients with conditions that require dietary changes. This review intends to describe the potential of yacon as a prebiotic and its cultivation and industrial processing for human consumption.
The ingestion of most dietary protein can cause systemic tolerance, and such tolerance is easier to induce in younger than in older mice. In this study, we examined whether oral tolerance to ovalbumin (OVA) could be induced in OVA-T-cell receptor (OVA-TCR)-specific transgenic mice. Continuous feeding or gavage with OVA induced tolerance, measured as reduced antibody production, in young and aged BALB/c mice, in a dose-dependent manner, but this effect was not observed in transgenic mice. Once BALB/c mice became tolerant, this state was maintained for over 44 weeks, although the tolerant state could be reversed by adoptive cell transfer. DO11.10 mice did not become tolerant upon continuous feeding with OVA, and the adoptive transfer of naïve cells increased the levels of specific antibodies in their sera after antigenic challenge. The immunization schedule used here leads to a Th2-dependent antibody response in normal BALB/c mice. However, the same schedule induced both Th1-and Th2-antibody responses in transgenic mice. Dendritic cells (DC) from tolerant BALB/c mice were less efficient in the induction of the proliferation of cocultured T cells from both BALB/c and DO11.10 mice, as well as Th1 [interleukin (IL)-2 and interferon (IFN)-g] and Th2 (IL-4 and IL-10) cytokine production. The DC from DO11.10 transgenic mice were equally efficient in the induction of T-cell proliferation in both normal and transgenic mice, as well as in the induction of Th1 and Th2 cytokines, whether or not the mice consumed OVA. Transforming growth factor (TGF)-b secretion was significantly lower in the supernatants of T cells from both normal and transgenic mice cocultured with DC from DO11.10 mice that had consumed OVA, while it was significantly higher in the presence of DC from normal tolerant mice, thus implicating TGF-b as a regulatory cytokine in oral tolerance in the murine model.
BackgroundValproic acid (VPA) is a potent anticonvulsant that inhibits histone deacetylases. Because of this inhibitory action, we investigated whether VPA would affect chromatin supraorganization, mitotic indices and the frequency of chromosome abnormalities and cell death in HeLa cells.Methodology/Principal FindingsImage analysis was performed by scanning microspectrophotometry for cells cultivated for 24 h, treated with 0.05, 0.5 or 1.0 mM VPA for 1–24 h, and subjected to the Feulgen reaction. TSA-treated cells were used as a predictable positive control. DNA fragmentation was investigated with the TUNEL assay. Chromatin decondensation was demonstrated under TSA and all VPA treatments, but no changes in chromosome abnormalities, mitotic indices or morphologically identified cell death were found with the VPA treatment conditions mentioned above, although decreased mitotic indices were detected under higher VPA concentration and longer exposure time. The frequency of DNA fragmentation identified with the TUNEL assay in HeLa cells increased after a 24-h VPA treatment, although this fragmentation occurred much earlier after treatment with TSA.Conclusions/SignificanceThe inhibition of histone deacetylases by VPA induces chromatin remodeling in HeLa cells, which suggests an association to altered gene expression. Under VPA doses close to the therapeutic antiepileptic plasma range no changes in cell proliferation or chromosome abnormalities are elicited. The DNA fragmentation results indicate that a longer exposure to VPA or a higher VPA concentration is required for the induction of cell death.
Dietary proteins play an important role in the regulation of systemic immune response, in a phenomenon known as oral tolerance (OT). To evaluate the effects of OT on a murine model of type II collagen (CII) plus ovalbumin (OVA)-induced arthritis (CIA), mice were fed with OVA either before or after CIA induction. OT significantly reduced the paw edema and synovial inflammation, as well as serum levels of anti-CII, the ex vivo proliferation and inflammatory cytokine production by spleen cells from CIA mice. The frequencies of Foxp3(+) and IL-10(+) cells were higher, whereas IFNγ(+) cells and IL-17(+) cells were lower, among gated CD4(+) spleen T cells from tolerized CIA mice than in those from non-tolerized CIA mice. Adoptive transfer of tolerogenic dendritic cells (DCs) before CIA induction mimics the effects observed in the OT. We demonstrate here that bystander suppression induced by OT can modify the course of CIA and tolerogenic DCs play a role this phenomenon.
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