ABSTRACT Bacterial spot caused by Xanthomonas spp. (X. vesicatoria, X. euvesicatoria pv. euvesicatoria, X. euvesicatoria pv. perforans, and X. hortorum pv. gardneri) may result in significant losses for tomato crops. Simonkolleite nanoparticles (SK-NPs) has been indicated as a novel approach for plant disease control. The objective of this work was to evaluate SK-NPs (ZnOCl, ZnOCl:Ag, and ZnOCl:Cu at different concentrations) for the in vitro inhibition of X. hortorum pv. gardneri, determining the time of exposure of the products for the bacterial death; the reduction of bacteria recovery on inoculated seeds, and their efficacy to reduce bacterial spot severity in plant. The growth inhibition was evaluated by inhibition zone in culture medium plates, when the diameter of the inhibition zone was measured. The period of exposure of the products to the bacterial suspension tested were 1, 2, 3, 4, or 5 h. Tomato inoculated seeds were treated with SK-NPs. In plant, the preventive and curative effects were evaluated by applying the products two days before or after inoculation, respectively. Disease severity was evaluated and the area under the disease progress curve (AUDPC) was calculated. ZnOCl:Ag, ZnOCl:Cu, and ZnOCl inhibited bacterial growth, and the 5 h exposure time was necessary to reduce bacterial growth. ZnOCl:Ag, and ZnOCl:Cu reduced the bacteria presence in the seeds, and did not affect the seed germination. Both products reduced the AUDPC in the preventive application. The use of SK-NPs ZnOCl:Ag and ZnOCl:Cu showed to be promising to manage tomato bacterial spot.

RESUMO A mancha bacteriana causada por Xanthomonas spp. (X. vesicatoria, X. euvesicatoria pv. euvesicatoria, X. euvesicatoria pv. perforans, and X. hortorum pv. gardneri) pode provocar perdas significativas na produção do tomateiro. As nanopartículas de Simonkolleite (NPs-SK) tem sido indicada como uma inovação para o controle de doenças de plantas. O objetivo do trabalho foi avaliar o uso de NPs-SK (ZnOCl, ZnOCl:Ag e ZnOCl:Cu em diferentes concentrações) na inibição do crescimento de X. hortorum pv. gardneri in vitro, determinar o tempo de exposição dos produtos para causar a morte bacteriana, a redução da bactéria em sementes inoculadas e sua eficácia na redução da severidade da mancha bacteriana em plantas. A inibição do crescimento foi avaliada pela zona de inibição em meio de cultura, quando o diâmetro da zona de inibição foi medido. O período de exposição dos produtos à suspensão bacteriana foi testado por 1, 2, 3, 4 e 5 h. As sementes de tomate inoculadas foram tratadas com as NPs-SK. Em plantas, o efeito da aplicação preventiva e curativa dos produtos foram avaliadas dois dias antes e após a inoculação, respectivamente. A severidade da doença foi avaliada e calculada a área abaixo da curva de progresso da doença (AACPD). ZnOCl:Ag, ZnOCl:Cu e ZnOCl inibiram o crescimento bacteriano e o tempo de exposição de 5 h foi necessário para reduzir a população bacteriana. ZnOCl:Ag e ZnOCl:Cu reduziram a presença da bactéria nas sementes, não afetando a germinação. Os dois produtos reduziram a AACPD em aplicação preventiva. O uso das NPs-SK ZnOCl:Ag e ZnOCl:Cu mostraram promissores para o manejo da mancha bacteriana do tomateiro.

RESUMO: A mancha branca do milho (MBM) causada por Pantoea ananatis é uma das principais doenças foliares da cultura, e as nanopartículas (NPs) surgem como inovação no controle de doenças bacterianas. O objetivo do presente trabalho foi avaliar a toxidez de NPs puras e dopadas com diferentes elementos, na inibição do crescimento bacteriano e no controle da MBM. NPs puras e NPs de ZnO dopadas com: prata (Ag), ouro (Au), cobre (Cu), ferro (Fe), manganês (Mn), e níquel (Ni) em diferentes concentrações foram usadas para determinar a toxidez à P. ananatis, avaliando-se o halo de inibição do crescimento bacteriano. Para avaliar o controle da MBM, na aplicação preventiva, plantas de milho foram pulverizadas com NPs de ZnO:0.1Cu, ZnO:0.05Fe, ZnO:0.2Mn e ZnO:0.7Ni a 10, 5 e 2.5 mg mL-1, e três dias depois foram inoculadas com a suspensão bacteriana. Na aplicação curativa, as plantas foram inoculadas com a suspensão bacteriana e três dias após pulverizadas com as NPs. A severidade da doença foi avaliada e calculada a área abaixo da curva de progresso da doença (AACPD). NPs de ZnO dopadas com os diferentes elementos e concentrações inibiram o crescimento bacteriano in vitro. As NPs de ZnO:0.1Cu e ZnO:0.2Mn a 5 e 2.5 mg mL-1, nas duas aplicações reduziram a severidade da MBM, apresentando potencial de uso no manejo da doença.

ABSTRACT: Maize white spot (MWS) caused by Pantoea ananatis is one main maize leaf diseases, and nanoparticles (NPs) are an innovative approach for bacterial disease control. This research evaluated the toxicity of pure NPs and doped NPs with different elements in inhibiting bacterial growth and to control MWS. Pure NPs and ZnO NPs doped with silver (Ag), gold (Au), copper (Cu), iron (Fe), manganese (Mn), and nickel (Ni) at different concentrations were used to determine the toxicity for P. ananatis in vitro, evaluating the bacterial growth inhibition zone. To assess the control of MWS, in the preventive application, maize plants were sprayed with NPs of ZnO:0.1Cu, ZnO:0.05Fe, ZnO:0.2Mn and ZnO:0.7Ni at 10, 5 or 2.5 mg mL-1, and after 3 days, the plants were inoculated with bacterial suspension. To assess the curative application, plants were inoculated with the bacteria, and 3 days later sprayed with the NPs. The disease severity was assessed and the area under the disease-progress curve (AUDPC) was calculated. The doped ZnO NPs with different elements, and at different concentrations inhibited bacterial growth in vitro. NPs of ZnO:0.1Cu and ZnO:0.2Mn at 5 or 2.5 mg mL-1, in both applications reduced the severity of MWS, showing potential for use in the disease management.

Abstract The aim of this study was to analyze the structural, morphological and mechanical properties of two different lithium disilicate glass-reinforced ceramics for CAD-CAM systems (IPS e.max CAD and Rosetta SM). Five methodologies were used for both ceramics: microstructure (n = 2) was analyzed using x-ray diffraction (XRD); morphological properties (n = 2) were analyzed by scanning electron microscopy (SEM), with and without hydrofluoric etching; porosity (n = 3) was assessed using 3D micro-computed tomography (micro-CT); flexural strength was measured (n =1 0) using the three-point bending test; and bond strength was determined with self-adhesive resin cement (n = 10), using a microshear bond test. After performing all the tests, the data were analyzed using t-Student test and two-way ANOVA. All the tests used a significance level of α = 0.05. High peak positions corresponding to standard lithium metasilicate and lithium disilicate with similar intensities were observed for both ceramics in the XRD analysis. Morphological analysis showed that the crystalline structure of the two ceramics studied showed no statistical difference after acid etching. Additionally, no significant differences were recorded in the number or size of the pores for the ceramics evaluated. Moreover, no differences in flexural strength were found for the ceramic materials tested, or in the bond strength to ceramic substrates for the resin cements. Based on the study results, no significant differences were found between the two CAD-CAM lithium disilicate glass-reinforced ceramics tested, since they presented similar crystalline structures with comparable intensities, and similar total porosity, flexural strength and bond strength.

Abstract Background: Snake venoms are a complex mixture of proteins, organic and inorganic compounds. Some of these proteins, enzymatic or non-enzymatic ones, are able to interact with platelet receptors, causing hemostatic disorders. The possible therapeutic potential of toxins with antiplatelet properties may arouse interest in the pharmacological areas. The present study aimed to purify and characterize an antiplatelet DC protein from Bothrops alternatus snake venom. Methods: The protein, called BaltDC (DC protein from B. alternatus snake venom), was purified by a combination of ion-exchange chromatography on DEAE-Sephacel column and gel filtration on Sephadex G-75. The molecular mass was estimated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE). The amino acid sequence of the N-terminal region was carried out by Edman degradation method. Platelet aggregation assays were performed in human platelet-rich plasma (PRP). Infrared (IR) spectroscopy was used in order to elucidate the interactions between BaltDC and platelet membrane. Results: BaltDC ran as a single protein band on SDS-PAGE and showed apparent molecular mass of 32 kDa under reducing or non-reducing conditions. The N-terminal region of the purified protein revealed the amino acid sequence IISPPVCGNELLEVGEECDCGTPENCQNECCDA, which showed identity with other snake venom metalloproteinases (SVMPs). BaltDC was devoid of proteolytic, hemorrhagic, defibrinating or coagulant activities, but it showed a specific inhibitory effect on platelet aggregation induced by ristocetin and epinephrine in PRP. IR analysis spectra strongly suggests that PO 3 2 − groups, present in BaltDC, form hydrogen bonds with the PO 2 − groups present in the non-lipid portion of the membrane platelets. Conclusions: BaltDC may be of medical interest since it was able to inhibit platelet aggregation.