42 research outputs found

    Effects of elevated [CO2 ] on maize defence against mycotoxigenic Fusarium verticillioides.

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    Maize is by quantity the most important C4 cereal crop; however, future climate changes are expected to increase maize susceptibility to mycotoxigenic fungal pathogens and reduce productivity. While rising atmospheric [CO2 ] is a driving force behind the warmer temperatures and drought, which aggravate fungal disease and mycotoxin accumulation, our understanding of how elevated [CO2 ] will effect maize defences against such pathogens is limited. Here we report that elevated [CO2 ] increases maize susceptibility to Fusarium verticillioides proliferation, while mycotoxin levels are unaltered. Fumonisin production is not proportional to the increase in F. verticillioides biomass, and the amount of fumonisin produced per unit pathogen is reduced at elevated [CO2 ]. Following F. verticillioides stalk inoculation, the accumulation of sugars, free fatty acids, lipoxygenase (LOX) transcripts, phytohormones and downstream phytoalexins is dampened in maize grown at elevated [CO2 ]. The attenuation of maize 13-LOXs and jasmonic acid production correlates with reduced terpenoid phytoalexins and increased susceptibility. Furthermore, the attenuated induction of 9-LOXs, which have been suggested to stimulate mycotoxin biosynthesis, is consistent with reduced fumonisin per unit fungal biomass at elevated [CO2 ]. Our findings suggest that elevated [CO2 ] will compromise maize LOX-dependent signalling, which will influence the interactions between maize and mycotoxigenic fungi

    Efecto genotóxico y citotóxico del plomo en meristemos radiculares de dos variedades de Vicia faba L. y su relación con la domesticación

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    Las problemáticas ambientales asociadas al incremento de metales pesados como el plomo han promovido la búsqueda de bioindicadores eficientes; Vicia faba es uno de los más utilizados, sin embargo, su aprovechamiento a nivel mundial ha provocado el uso indistinto de sus variedades silvestres y domesticadas, sin considerar las implicaciones del proceso de domesticación. Por tal motivo, la presente investigación tiene como objetivo evaluar el efecto genotóxico y citotóxico del plomo en células meristemáticas de raíz de semillas de V. faba  silvestre y de la variedad Major (domesticada) a través de la presencia de micronúcleos y la determinación del índice mitótico, con la finalidad de conocer sus respuestas ante este metal y su relación con la domesticación, así como sugerir el uso de la variedad más sensible como bioindicador. Para ello, los meristemos radiculares se sometieron a tratamientos con 0, 0.005, 0.01 y 0.02 g L-1 de acetato de plomo y se realizaron tinciones con aceto-orceína; se obtuvo la frecuencia de micronúcleos y el índice mitótico por cada 1000 células observadas. Los resultados obtenidos indican que el acetato de plomo tiene un efecto genotóxico y citotóxico diferencial entre ambas variedades, siendo V. faba var. Major la que presenta una alta sensibilidad al metal pesado, debido a una pérdida en la resistencia al estrés, por lo que se sugiere su uso como bioindicador; mientras que en las semillas silvestres mostraron mayor tolerancia al tener un bajo grado de domesticación

    Función sexual antes y después de la reparación quirúrgica del prolapso genital

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    Objetivo: Comparar la función sexual (FS) de mujeres con prolapso genital (PG) antes y después de su reparación quirúrgica. Métodos: Investigación de tipo comparativa y aplicada, con diseño cuasi experimental, prospectivo y de campo, donde se evaluó la FS de mujeres con diagnóstico de PG antes y después del tratamiento quirúrgico con técnicas convencionales, mediante el Cuestionario Sexual para Prolapso genital e Incontinencia Urinaria versión corta (PISQ-12). Resultados: Al comparar la FS antes y después de la cirugía reparadora del PG, se determinó que tanto la puntuación total del PISQ-12 (15,90 ± 6,51 vs. 32,17 ± 3,62) como las puntuaciones de las dimensiones respuesta sexual (5,87 ± 2,80 vs. 10,97 ± 2,80) y limitaciones sexuales femeninas (4,88 ± 3,90 vs. 16,77 ± 3,00) fueron significativamente más altas luego de la intervención quirúrgica (p<0,001), a excepción del indicador intensidad del orgasmo (0,80 ± 0,71 vs. 0,87± 0,73; p= 0,722) y la dimensión limitaciones sexuales de la pareja (4,37 ± 2,14 vs. 3,56 ± 2,70; p=0,815) donde sus puntuaciones antes y después del tratamiento quirúrgico no fueron estadísticamente significativas (p&gt;0,05). Conclusiones: Las mujeres con PG presentan una pobre FS, la cirugía reparadora del PG por técnicas convencionales mejoró significativamente la FS de las pacientes con disfunción del piso pélvico, permitiéndoles obtener a estas mujeres una vida sexual más placentera, con mejoría de su calidad de vida

    Polyclonal antibodies for the detection of Trypanosoma cruzi circulating antigens

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    Detection of Trypanosoma cruzi antigens in clinical samples is considered an important diagnostic tool for Chagas disease. The production and use of polyclonal antibodies may contribute to an increase in the sensitivity of immunodiagnosis of Chagas disease.Polyclonal antibodies were raised in alpacas, rabbits, and hens immunized with trypomastigote excreted-secreted antigen, membrane proteins, trypomastigote lysate antigen and recombinant 1F8 to produce polyclonal antibodies. Western blot analysis was performed to determine specificity of the developed antibodies. An antigen capture ELISA of circulating antigens in serum, plasma and urine samples was developed using IgY polyclonal antibodies against T. cruzi membrane antigens (capture antibody) and IgG from alpaca raised against TESA. A total of 33 serum, 23 plasma and 9 urine samples were analyzed using the developed test. Among serum samples, compared to serology, the antigen capture ELISA tested positive in 55% of samples. All plasma samples from serology positive subjects were positive in the antigen capture ELISA. All urine positive samples had corresponding plasma samples that were also positive when tested by the antigen capture ELISA.Polyclonal antibodies are useful for detection of circulating antigens in both the plasma and urine of infected individuals. Detection of antigens is direct evidence of the presence of the parasite, and could be a better surrogate of current infection status

    NR 40. Effect of multinutrient blocks hardness on voluntary intake on crossbred bovines

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    An experiment was conducted under tropical dry forest conditions in order to evaluate the storage effect of the multinutrient blocks (BM) on hardness (R), voluntary (CV) and total dry matter intake (CMS), daily gain (GP), feed efficiency (EA) in 20 crossbred of 264 kg of average body weight (PV) in feedlot. The animal’s diet was based in Brachiaria humidicola hay (4.44 % PC) and the suplemmentation with BM. The statistic design was a completely randomized and the experimental unit was an animal, where T0: hay (control), T1: BM 15 days + hay, T2: BM 30 days + hay, T3: BM 45 days + hay. BM (30 x 15 cm) were manufactured in a cilinder molds and carried to the hydraulic concrete testing machine and evaluate resistance in kg/cm2. Increasing storage time affected (P&lt;.01) BM hardness T1: 2.33 kg/cm2 in relation to the T2 and T3 (3.24 and 3.40 kg/cm2) respectively. The CV was affected by treatments: T1 presented the greater consumption (0.75 kg/day/100 kg of PV) followed by the T2 and T3 (0.53 and 0.51 kg/day/100 kg of PV) respectively. Dry matter intake (CMS), daily gain (GP) and feed efficiency (EA) were influenced (P&lt;.01) by BM

    Streptococcal erythrogenic toxin B induces apoptosis and proliferation in human leukocytes

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    Streptococcal erythrogenic toxin B induces apoptosis and proliferation in human leukocytes.BackgroundPrevious reports have shown the presence of erythrogenic toxin type B (ETB), apoptosis, proliferation, and leukocyte infiltration in biopsies from patients with acute poststreptococcal glomerulonephritis (APSGN).MethodsAttempting to correlate the apoptotic and proliferative events with the interaction of ETB or its precursor (ETBP) with leukocytes, mononuclear leukocytes from 12 healthy subjects were cultured with ETB or ETBP to analyze the levels of apoptosis, proliferation, expression of modulatory apoptosis gene products, and oxidative metabolism. After four days of incubation, cells were assessed for apoptosis by morphological criteria, annexin V assay, and terminal deoxy transferase uridine triphosphate nick end-labeling (TUNEL) assay. The expression of regulatory apoptosis genes was assessed by relevant monoclonal antibodies; proliferation was by incorporation of radioactive thymidine; and oxidative metabolism was by oxidation of 2′,7′-dichlorofuorescein diacetate to 2′,7′-dichlorofuorescein. Neutralization of Fas-L and cysteine protease activity of ETB were performed by incubation of ETB-treated leukocyte cultures with anti-human Fas-L mAb or with E64, respectively.ResultsElevated levels of apoptosis in ETBP/ETB-treated leukocytes were found when compared with controls: morphological criteria (P < 0.01), Annexin V (control, 5.01 ± 0.61; ETBP, 10.60 ± 1.98%, P = 0.0005), and TUNEL (control, 12.5 ± 2.6; ETBP, 20.56 ± 3.06%, P = 0.001; ETB, 30.69 ± 5.05%, P = 0.001). Increased expression of apoptosis was accompanied by increased expression of Fas (control, 20.15 ± 5.28; ETBP, 43.51 ± 5.6%, P = 0.03; ETB, 47.16 ± 5.54%, P = 0.01), Fas ligand (control, 5.64 ± 2.38; ETBP, 11.66 ± 3.65%, P = 0.04; ETB, 16.39 ± 5.05%, P = 0.02) and p53 products (control, 9.22 ± 3.44; ETBP, 22.82 ± 5.72%, P = 0.01; ETB, 24.60 ± 5.20%, P = 0.01). Treatment of ETB-leukocyte cultures with anti-human Fas-L exhibited 2.2-fold lower apoptosis expression. Treatment with E64 significantly abrogated the apoptotic effect of ETB. There was no increment on leukocyte oxidative metabolism. Mononuclear leukocytes also showed elevated levels of proliferation when treated with different concentrations (from 50 to 6.2 μg/mL) of streptococcal proteins (Stimulation index ranging: ETBP, 5.6 ± 1.9 to 6.4 ± 1.9; ETB, 9.9 ± 2.8 to 13.9 ± 3.8).ConclusionsThese results delineate an additional pathway for the pathogenesis of APSGN related to the role of cationic streptococcal ETB or ETBP on the induction of apoptosis and proliferation during the course of the disease

    L-citrulline protects from kidney damage in type 1 diabetic mice.

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    Rationale. Diabetic nephropathy is a major cause of end-stage renal disease, associated with endothelial dysfunction. Chronic supplementation of L-arginine (L-arg), the substrate for endothelial nitric oxide synthase (eNOS), failed to improve vascular function. L-citrulline (L-cit) supplementation not only increases L-arg synthesis, but also inhibits cytosolic arginase I (Arg I), a competitor of eNOS for the use of L-arg, in the vasculature. Aims. To investigate whether L-cit treatment reduces diabetic nephropathy in streptozotocin (STZ)-induced type 1 diabetes in mice and rats and to study its effects on arginase II (ArgII) function, the main renal isoform. Methods. STZ-C57BL6 mice received L-cit or vehicle supplemented in the drinking water. For comparative analysis, diabetic ArgII knock out mice and L-cit-treated STZ-rats were evaluated. Results. L-cit exerted protective effects in kidneys of STZ-rats, and markedly reduced urinary albumin excretion, tubulo-interstitial fibrosis and kidney hypertrophy, observed in untreated diabetic mice. Intriguingly, L-cit treatment was accompanied by a sustained elevation of tubular ArgII at 16 wks and significantly enhanced plasma levels of the anti-inflammatory cytokine IL-10. Diabetic ArgII knock out mice showed greater BUN levels, hypertrophy, and dilated tubules than diabetic wild type mice. Despite a marked reduction in collagen deposition in ArgII knock out mice, their albuminuria was not significantly different from diabetic wild type animals. L-cit also restored NO/ROS balance and barrier function in high glucose-treated monolayers of human glomerular endothelial cells. Moreover, L-cit also has the ability to establish an anti-inflammatory profile, characterized by increased IL-10 and reduced IL-1beta and IL-12(p70) generation in the human proximal tubular cells. Conclusions. L-cit supplementation established an anti-inflammatory profile and significantly preserved the nephron function during type 1 diabetes. <br/

    Role of IL-6 in angiotensin II-induced retinal vascular inflammation. Invest

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    PURPOSE. The production of proinflammatory cytokines has been shown to play a critical role in a variety of retinal vascular diseases. Angiotensin II and VEGF have been implicated in the initiation of vascular inflammation and retinal vascular disease. However, detailed mechanisms of this process and interactions between inflammatory agonists and angiotensin II in promoting retinopathy are poorly understood. The present study was an investigation of the role of interleukin (IL)-6 in angiotensin II-induced retinopathy. METHODS. Rats and IL-6 -deficient and wild-type mice were treated with angiotensin II or IL-6, and their retinas were analyzed for leukocyte adhesion or for the expression and localization of VEGF or IL-6. Leukocyte adhesion was assayed by concanavalin A labeling. Vascular density was determined by morphometric analysis. NADPH oxidase activity was assayed by dihydroethidium imaging of superoxide. RESULTS. Intravitreal injection of angiotensin II caused increases in IL-6 mRNA and protein and in leukocyte adhesion to the retinal vessels. IL-6 protein was localized to CD11b-positive microglia and macrophage-like cells. Angiotensin II treatment stimulated increases in retinal levels of VEGF expression and NADPH oxidase activity, which were associated with increased surface area and remodeling of the retinal vessels. These effects were blocked by knocking out IL-6. Intravitreal IL-6 directly induced leukocyte adhesion in both wild-type and IL-6 -deficient mice. CONCLUSIONS. The results indicate that IL-6 expression is essential for angiotensin II-induced increases in retinal VEGF expression, leukostasis, and vascular remodeling. The data suggest a critical role for IL-6 in mediating angiotensin II-induced retinal vascular inflammation and remodeling. (Invest Ophthalmol Vis Sci
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