117 research outputs found

    A review of knowledge on the mechanisms of action of the rare sugar D‐tagatose against phytopathogenic oomycetes

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    d-tagatose is a rare monosaccharide, naturally present at low concentrations in some fruits and dairy products. d-tagatose is "generally recognized as safe" and is used as a low-calorie sweetener in the food industry. It is able to inhibit the growth of numerous microorganisms, such as phytopathogenic oomycetes responsible for important crop diseases. Thanks to the negligible effects on human health and the environment, d-tagatose has been proposed as a sustainable product for crop protection. This review describes the current knowledge on modes of action of d-tagatose against phytopathogenic oomycetes and its potential uses in agriculture. d-tagatose can negatively affect the growth of phytopathogenic oomycetes by inhibiting key enzymes of sugar metabolism, such as β-glucosidase in Phytophthora infestans, and fructokinase and phosphomannose isomerase in Hyaloperonospora arabidopsidis. Moreover, d-tagatose affects sugar content, causes severe mitochondrial alterations, and inhibits respiration processes with the accumulation of reactive oxygen species in P. infestans, but not in P. cinnamomi. Differential effects of d-tagatose are associated with a global gene downregulation in P. infestans and with an efficient transcriptional reprogramming of multiple metabolic processes in P. cinnamomi. d-tagatose displays possible species-specific effects in Phytophthora spp. and nutritional properties on some plant-associated microorganisms. However, inhibitory effects are reversible and P. infestans growth can be restored in the absence of d-tagatose. Further functional studies are discussed in this review, in order to promote the use of d-tagatose for sustainable crop protectio

    Using Heat to Characterize Streambed Water Flux Variability in Four Stream Reaches

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    Estimates of streambed water fl ux are needed for the interpretation of streambed chemistry and reactions. Continuous temperature and head monitoring in stream reaches within four agricultural watersheds (Leary Weber Ditch, IN; Maple Creek, NE; DR2 Drain, WA; and Merced River, CA) allowed heat to be used as a tracer to study the temporal and spatial variability of fluxes through the streambed. Synoptic methods (seepage meter and differential discharge measurements) were compared with estimates obtained by using heat as a tracer. Water flux was estimated by modeling one-dimensional vertical flow of water and heat using the model VS2DH. Flux was influenced by physical heterogeneity of the stream channel and temporal variability in stream and ground-water levels. During most of the study period (April–December 2004), flux was upward through the streambeds. At the IN, NE, and CA sites, high-stage events resulted in rapid reversal of flow direction inducing short-term surface-water flow into the streambed. During late summer at the IN site, regional ground-water levels dropped, leading to surface-water loss to ground water that resulted in drying of the ditch. Synoptic measurements of flux generally supported the model flux estimates. Water flow through the streambed was roughly an order of magnitude larger in the humid basins (IN and NE) than in the arid basins (WA and CA). Downward flux, in response to sudden high streamflows, and seasonal variability in flux was most pronounced in the humid basins and in high conductivity zones in the streambed

    Acute Upper Gastro-Intestinal Bleeding in Morocco: What Have Changed?

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    Objective. In the present study, we aimed to investigate epidemiological, clinical, and etiological characteristics of acute upper gastro-intestinal bleeding. Materials and Methods. This retrospective study was conducted between January 2003 and December 2008. It concerned all cases of acute upper gastroduodenal bleeding benefited from an urgent gastro-intestinal endoscopy in our department in Morocco. Characteristics of patients were evaluated in terms of age, gender, medical history, presenting symptoms, results of rectal and clinical examinations, and endoscopy findings. Results. 1389 cases were registered. As 66% of the patients were male, 34% were female. Mean age was 49. 12% of patients had a history of previous hemorrhage, and 26% had a history of NSAID and aspirin use. Endoscopy was performed in 96%. The gastroduodenal ulcer was the main etiology in 38%, followed by gastritis and duodenitis in 32.5%. Conclusion. AUGIB is still a frequent pathology, threatening patients' life. NSAID and aspirin are still the major risk factors. Their impact due to peptic ulcer remains stable in our country

    Non Hodgkin’s lymphoma secondary treatment with azathioprine in a chronic hepatitis autoimmune (second case of literature)

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    Les traitements immunosuppresseurs sont associés à une augmentation du risque de survenue de Lymphomes Malins Non Hodgkiniens (LMNH), en particulier chez les patients traités par azathioprine pour Maladies Inflammatoires Chroniques de l’Intestin (MICI), greffe d’organes, polyarthrite rhumatoïde. En revanche, nous ne disposons pas de données concernant la survenue LMNH sous azathioprine pour hépatite chronique auto-immune. Les auteurs rapportent le cas d’un patient traité par prednisolone et azathioprine, pendant 2 mois, suivis d’un relais par azathioprine seul en traitement d’entretien. L’évolution était favorable. Trois ans après, le patient a présenté un lymphome malin non hodgkinien ganglionnaire. À notre connaissance, cette observation illustre le deuxième cas de la littérature.Immunosuppressive treatments are associated with an increased risk of non-Hodgkin's lymphoma (LMNH), especially in patients treated with azathioprine for chronic inflammatory disease of the intestine (IBD), organ transplantation, rheumatoid arthritis. However, we do not have data on the occurrence LMNH under azathioprine for chronic hepatitis autoimmune. The authors report a case of patient receiving prednisolone and azathioprine for 2 months followed by a single relay azathioprine as maintenance treatment. The evolution was favourable. Three year later, the patient presented a malignant non-Hodgkin lymphoma ganglionnaire. In our knowledge, this observation is the second case reported in the literature

    Weight loss reduces basal-like breast cancer through kinome reprogramming

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    Additional file 1. Tumor burden and growth were not affected by diet. a. Tumor burden was quantified at sacrifice. b. Tumor volume was measured by calipers at detection and sacrifice. (N = 28 10 %; N = 31 60 %; N = 29, 60–10 %)

    Using Heat to Characterize Streambed Water Flux Variability in Four Stream Reaches

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    Estimates of streambed water fl ux are needed for the interpretation of streambed chemistry and reactions. Continuous temperature and head monitoring in stream reaches within four agricultural watersheds (Leary Weber Ditch, IN; Maple Creek, NE; DR2 Drain, WA; and Merced River, CA) allowed heat to be used as a tracer to study the temporal and spatial variability of fluxes through the streambed. Synoptic methods (seepage meter and differential discharge measurements) were compared with estimates obtained by using heat as a tracer. Water flux was estimated by modeling one-dimensional vertical flow of water and heat using the model VS2DH. Flux was influenced by physical heterogeneity of the stream channel and temporal variability in stream and ground-water levels. During most of the study period (April–December 2004), flux was upward through the streambeds. At the IN, NE, and CA sites, high-stage events resulted in rapid reversal of flow direction inducing short-term surface-water flow into the streambed. During late summer at the IN site, regional ground-water levels dropped, leading to surface-water loss to ground water that resulted in drying of the ditch. Synoptic measurements of flux generally supported the model flux estimates. Water flow through the streambed was roughly an order of magnitude larger in the humid basins (IN and NE) than in the arid basins (WA and CA). Downward flux, in response to sudden high streamflows, and seasonal variability in flux was most pronounced in the humid basins and in high conductivity zones in the streambed

    cMET inhibitor crizotinib impairs angiogenesis and reduces tumor burden in the C3(1)-Tag model of basal-like breast cancer

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    Epidemiologic studies have associated obesity with increased risk of the aggressive basal-like breast cancer (BBC) subtype. Hepatocyte growth factor (HGF) signaling through its receptor, cMET, is elevated in obesity and is a pro-tumorigenic pathway strongly associated with BBC. We previously reported that high fat diet (HFD) elevated HGF, cMET, and phospho-cMET in normal mammary gland, with accelerated tumor development, compared to low fat diet (LFD)-fed lean controls in a murine model of BBC. We also showed that weight loss resulted in a significant reversal of HFD-induced effects on latency and elevation of HGF/cMET signaling in normal mammary and cMET in normal mammary and tumors. Here, we sought to inhibit BBC tumor progression in LFD- and HFD-fed C3(1)-Tag BBC mice using a small molecule cMET inhibitor, and began crizotinib treatment (50mg/kg body weight by oral gavage) upon identification of the first palpable tumor. We next investigated if administering crizotinib in a window prior to tumor development would inhibit or delay BBC tumorigenesis. Treatment: Crizotinib significantly reduced mean tumor burden by 27.96 and 37.29%, and mean tumor vascularity by 35.04 and 33.52%, in our LFD- and HFD-fed C3(1)-Tag BBC mice, respectively. Prevention: Crizotinib significantly accelerated primary tumor progression in both diet groups but had no effect on total tumor progression or total tumor burden. In sum, cMET inhibition by crizotinib limited tumor development and microvascular density in basal-like tumor-bearing mice but did not appear to be an effective preventive agent for BBC.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-1920-3) contains supplementary material, which is available to authorized users

    Osmotic Stress and ABA Affect Immune Response and Susceptibility of Grapevine Berries to Gray Mold by Priming Polyamine Accumulation

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    Abiotic factors inducing osmotic stress can affect plant immunity and resistance against pathogen attack. Although a number of studies have characterized grapevine responses to various forms of biotic and abiotic stresses, the relationships between osmotic stress response and susceptibility of mature berries to Botrytis cinerea still remain unknown. In this study, we investigated the effects of osmotic stress and abscisic acid (ABA) on defense responses of mature grapevine berries before and after B. cinerea infection. We focused on the possible involvement of polyamines in the interaction between osmotic stress response and susceptibility to B. cinerea. We showed that osmotic stress induced by PEG or sucrose, and exogenous ABA induce transient but low defense responses, including weak expression of PR genes and phytoalexin synthesis in mature berries. This was accompanied by an upregulation of NCED2 involved in ABA biosynthesis and a large production of free polyamines. However, osmotic stress followed by B. cinerea infection primed berries for enhanced accumulation of polyamines, but slowed down the defense responses and increased susceptibility to the pathogen. A weak increase of diamine- and polyamine-oxidase activities was also recorded in stressed berries, but declined after pathogen infection. The pretreatment of stressed berries with appropriate inhibitors of diamine- and polyamine-oxidases further increased polyamine level and greatly lowered defense responses, leading to higher susceptibility to B. cinerea. These results suggest that increased polyamine titer through low activation of their oxidative degradation in grape berries may contribute at least in part to the weakening of defense responses and subsequent disease susceptibility
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