Foliar‐applied xantham gum, commercially available exopolysaccharides from Xanthomonas campestris pv. campestris bacterial capsule, together with conidial suspension of heat‐inactivated pathogens were tested in relation to their ability to induce local and systemic protection against leaf spot diseases caused by Bipolaris sorokiniana, Bipolaris bicolor and Drechslera tritici‐repentis. Xantham gum preparation and heat‐inactivated conidial suspension were effective in inducing local and systemic protection when applied 48 h before the challenge with the pathogen. Microscopic studies of pathogen development in protected and control leaves indicated that neither germination and appressoria formation nor number of papillae were affected by treatment with xantham gum and heat‐inactivated conidial suspension. Increased activity of β‐1,3 glucanases was correlated with the induction of resistance and showed that protection induced in wheat leaves treated with the fungicide propiconazole presented a different mechanism of action.
BackgroundIndoleamine 2, 3-dioxygenase (IDO) is an immunomodulatory molecule that has been implicated in several biological processes. Although IDO has been linked with some renal diseases, its role in renal fibrosis is still unclear. Because IDO may be modulated by TGF-β1, a potent fibrogenic molecule, we hypothesized that IDO could be involved in renal fibrosis, especially acting in the TGF-β1-induced tubular epithelial-mesenchymal transition (EMT). We analyzed the IDO expression and activity in a model of renal fibrogenesis, and the effect of the IDO inhibitor 1-methyl-tryptophan (MT) on TGF-β1-induced EMT using tubular cell culture.MethodsMale Wistar rats where submited to 7 days of UUO. Non-obstructed kidneys (CL) and kidneys from SHAM rats were used as controls. Masson’s Tricrome and macrophages counting were used to chatacterize the tissue fibrosis. The EMT was analysed though immunohistochemistry and qRT-PCR. Immunohistochemestry in tissue has used to show IDO expression.MDCK cells were incubated with TGF- β1 to analyse IDO expression. Additionally, effects of TGF- β1 and the inhibition of IDO over the EMT process was acessed by immunoessays and scrath wound essay.ResultsIDO was markedly expressed in cortical and medular tubules of the UUO kidneys. Similarly to the immunolocalizaton of TGF- β1, accompanied by loss of e-cadherin expression and an increase of mesenchymal markers. Results in vitro with MDCK cells, showed that IDO was increased after stimulus with TGF-β1, and treatment with MT potentiated its expression. MDCK stimulated with TGF-β1 had higher migratory activity (scratch-wound assay), which was exacerbated by MT treatment.ConclusionsIDO is constitutively expressed in tubular cells and increases during renal fibrogenesis. Although IDO is induced by TGF-β1 in tubular cells, its chemical inhibitor acts as a profibrotic agent.
Foliar‐applied exopolysaccharides, obtained from bacterial cells of either Xanthomonas campestris pv. manihotis (EPS‐Xcm) or Xanthomonas campestris pv. campestris (EPS‐Xcc), isolate NRRL B‐1459, were tested for their ability to induce local and systemic protection against coffee leaf rust caused by Hemileia vastatrix. Both preparations of EPS were effective in inducing local and systemic protection when applied 72 h before challenge with the pathogen. Protection was also observed when plants were treated with different concentrations of a commercially available preparation of xanthan gum (CXG).
Systemic protection was induced by EPS‐Xcm, EPS‐Xcc and CXG even after the removal of the treated leaves immediately before the challenge. Local protection lasted at least 5 weeks, when EPS‐Xcm was applied at the concentration of 100 μg equivalents of glucose/ml. Fluorescent microscopic studies of pathogen development in protected and control leaves indicated that neither the germination, appressoria formation nor the number of infection sites were affected by treatment with EPS‐Xcm.
The guava pectin methylesterase (PME) specific activity and vitamin C were assayed in samples from different phases of guava fruit development. The PME enzyme from guava was extracted with borate-acetate buffer, 50 mol/l, pH 8.0, in the presence of NaCl 0.3 mol/l. The results showed PME optimum activity at pH 9 and 95 degrees C, and it is a thermostable enzyme. Guava PME retained 96.8% of activity after 300 min in 90 degrees C. Electrophoresis showed that guava PME contained two isoforms, one with 57 kDa molecular mass. The analyses of the different phases of guava maturation showed that ascorbic acid decreases during the maturation process, but PME activity increases with maturation.
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