The activity of Pleurotus ostreatus extracts against pathogenic fusaria

A P. ostreatus strain, appreciated as food and for the production of nutraceuticals, was grown on a commercial substrate, dried at low temperature (<40\ub0C) and grinded in order to produce a mushroom powder. The bioactivity of the water extract conserved at 4\ub0C in the dark was then assessed on F. graminearum, F. culmorum and F. musae at different time points from production (4 hrs, 40 days, 4 months). Moreover, the effect of the extracts on trichothecene type B production was measured exploiting a F. graminearum isolate expressing GFP-tagged trichodiene synthase. This allowed to monitor the first step of toxin production using a microplate fluorimeter. While mycelial growth of F. graminearum and F. culmorum was completely blocked at 3 mg/ml, mycelial growth of F. musae was inhibited at 90%. MIC50 was measured for F. graminearum and F. culmorum at 300 micrograms/mL. A loss of the bioactivity of P. ostreaus water extract on fungal growth was observed at 40 days (-30%) and of a further -30% at 4 months. A preliminary study on the biological activities of the extract identified a strong protease activity associated to low molecular weight proteins. Their bioactivity decreased over storage time in accordance with a decreased proteolytic activity. The P. ostreatus extract modulates trichothecene production independently from the protease activity, even at concentration where no mycelium inhibition was observed (down to 0.75 micrograms/mL). Studies on the genetic determinants of the protease activity as well as the compounds able to modulate trichothecene production are ongoing

Selection of an Endophytic Streptomyces sp. Strain DEF09 From Wheat Roots as a Biocontrol Agent Against Fusarium graminearum

Selection of biological control agents (BCA) profits from an integrated study of the tripartite interactions occurring among the BCA, the plant and the pathogen. The environment plays a crucial role in the efficacy of BCA, therefore, the selection process shall utmost mimic naturally occurring conditions. To identify effective biocontrol strains against Fusarium graminearum, the major cause of Fusarium head blight (FHB) in wheat and deoxynivalenol (DON) accumulation in grains, a workflow consisting of in vitro and in vivo assays was set up. Twenty-one Streptomyces strains, 16 of which were endophytes of different plants, were analyzed. In vitro and in vivo tests characterized their plant growth promoting (PGP) traits. Biocontrol activity against F. graminearum was firstly assessed with a dual culture assay. An in vivo germination blotter assay measured Fusarium foot rot and root rot symptoms (FFR-FRR) reduction as well as growth parameters of the plant treated with the Streptomyces strains. A selected subset of Streptomyces spp. strains was then assessed in a growth chamber measuring FFR symptoms and growth parameters of the wheat plant. The approach led to the identification of an effective Streptomyces sp. strain, DEF09, able to inhibit FHB on wheat in controlled conditions by blocking the spread of the pathogen at the infection site. The results were further confirmed in field conditions on both bread and durum wheat, where DEF09 decreased disease severity up to 60%. This work confirms that FRR and FFR pathosystems can be used to identify BCA effective against FHB

Increased sympathetic activity in normotensive offspring of malignant hypertensive parents compared to offspring of normotensive parents

Malignant hypertension seems to be the consequence of very high blood pressure. Furthermore, an increase in sympathetic and renin-angiotensin system activity is considered to be the main mechanisms producing malignant hypertension. In the present study, 10 offspring of malignant hypertensive (OMH) parents (age 28 ± 5 years, 7 males, 3 females, 2 white and 8 non-white) and 10 offspring of normotensive (ONT) parents (age 28 ± 6 years, 2 males, 8 females, 3 white and 7 non-white) were evaluated. The OMH group had significantly higher (P < 0.05) casual blood pressure (125 ± 10/81 ± 5 mmHg) compared with ONT (99 ± 13/67 ± 5 mmHg). The increase in blood pressure was greater in OMH (&#916; SBP = 17 ± 2 vs &#916; SBP = 9 ± 1 mmHg in ONT) during cold pressor testing, but they had a lower increase in heart rate (&#916; HR = 13 ± 2 vs &#916; HR = 20 ± 3 bpm in ONT) during isometric exercise (handgrip test). Sympathetic activity, measured by microneurography, was significantly higher (P < 0.05) before exercise in OMH (17 ± 6 vs 11 ± 4 burst/min in ONT) and exhibited a greater increase (&#916; = 18 ± 10 vs &#916; = 8 ± 3 burst/min in ONT) during isometric exercise. This study showed increased sympathetic activity in OMH before exercise and a greater response during isometric exercise, suggesting an autonomic abnormality before exercise and a greater sympathetic response to physical stress in OMH compared to ONT

Investigating Useful Properties of Four Streptomyces Strains Active against Fusarium graminearum Growth and Deoxynivalenol Production on Wheat Grains by qPCR

Streptomyces spp. can be exploited as biocontrol agents (BCAs) against plant pathogens such as Fusarium graminearum, the main causal agent of Fusarium head blight (FHB) and against the contamination of grains with deoxynivalenol (DON). In the present research, four Streptomyces strains active against F. graminearum in dual plate assays were characterized for their ability to colonize detached wheat grains in the presence of F. graminearum and to limit DON production. The pathogen and BCA abundance were assessed by a quantitative real-time PCR, while DON production was assessed by HPLC quantification and compared to ergosterol to correlate the toxin production to the amount of fungal mycelium. Fungal growth and mycotoxin production were assessed with both co-inoculation and late inoculation of the BCAs in vitro (three days post-Fusarium inoculation) to test the interaction between the fungus and the bacteria. The level of inhibition of the pathogen and the toxin production were strain-specific. Overall, a higher level of DON inhibition (up to 99%) and a strong reduction in fungal biomass (up to 71%) were achieved when streptomycetes were co-inoculated with the fungus. This research enabled studying the antifungal efficacy of the four Streptomyces strains and monitoring their development in DON-inducing conditions

Use of Streptomyces spp. as biocontrol agents of wheat crown rot caused by fusaria

Crown rot of wheat is caused mainly by Fusarium species and in specific climatic conditions can reduce production up to 50-90%. Biocontrol methods are an interesting approach to satisfy the increasing demand for alternatives to chemical fungicides. Streptomyces spp. act as growth promoters as well as biocontrol agents. Therefore, they are promising candidates for seed treatments, which combine their ability to produce a wide range of biologically active molecules with the potential to establish tight interactions with plants. Forty-seven Streptomyces spp. strains were selected among 1500, isolated from roots or rhizosphere of various crops. Their ability to reduce mycelial growth (up to 80%) of five Fusarium graminearum and F. culmorum strains (N=5), representing geographical, genotypic and toxigenic diversity, was determined in vitro. Streptomycetes showing inhibition >20% were further tested in vitro on wheat seedlings (cv. Bandera) for their ability to reduce disease symptoms. The root-necrosis was reduced up to 50% after 4 dpi. Moreover, the strains reduced the severity of crown rot up to 80% after 6 dpi in comparison to the untreated control. The selected strains did not inhibit the growth of the seedlings at the tested condition. Further in vivo studies are foreseen to assess their plant growth promoting ability. Until now, our results confirm that streptomycetes are a promising source for developing organic seed treatments

Phenotypic and genotypic diversity in Ciborinia camelliae Kohn isolates from Italy

Ciborinia camelliae, causal agent of Camellia flower blight, belongs to Ascomycota, family Sclerotiniaceae. The pathogen shows host and organ specificity infecting only flowers of camellias, causing a serious damage not only to the ornamental component of the plant, but interfering with the fruit development reducing thus the seed yield and oil production. Interestingly, ascomata of Ciborinia show an anti-feeding effect on collembola, suggesting its importance for the production of novel bioactive compounds. From Japan the pathogen spread worldwide quickly and despite it has been reported in all camellia-cultivated areas few studies have been carried out from a mycological and population variability point of view. Thirty strains from five Italian regions were characterized on four different culture media at six temperatures, describing their development daily up to 14 days. Based on these data 10 different morphotypes of C. camelliae were characterized. Multigene sequencing and universally primed PCR technique were used to assess genetic variability among C. camelliae isolates. The genotypic approach confirmed the phenotypic variability among the Italian strains compared to the results of other research groups. Further studies are therefore needed in this sector considering also the geographical distribution of the pathogen. Finally, exploiting fungal variability found in our samples may lead to the identification of strains able to produce high levels of bioactive molecules against insect pests or microorganisms

Development of a Fusarium graminearum biosensor assay to monitor the activity of naturally derived products to control trichothecene production

In the present study, we developed a microplate reader assay to detect natural products able to limit toxin production by the fungus Fusarium graminearum, the major cause of Fusarium Head Blight in cereals and trichothecene contamination in grains worldwide. In the biosensor assay, we exploited a F. graminearum isolate expressing GFP-tagged trichodiene synthase, encoded by TRI5 (TRI5-GFP), which catalyses the first step of the trichothecene biosynthesis pathway. This allowed us to monitor the first step of toxin production by fluorimetric assay. Fungal spores were treated with filtrates from streptomycete liquid cultures in order to evaluate their influence on fungal growth and toxin production, integrating absorbance and fluorescence measurements. The correlation between the fluorimetric assay based on the TRI5-GFP detection and the amount of deoxynivalenol (DON) measured with ELISA technique was assessed. The new method allowed to identify crude filtrates able to reduce toxin production as accurately as ELISA. The main advantages of the newly developed assay are the reduction of the analysis costs and lower use of chemicals and consumables. It contributes to increase the speed and capacity to screen large set of molecules and natural extracts. A historical collection of Streptomyces strains was screened by the newly developed method and five bacterial strains have been identified as producing bioactive molecules able to inhibit the fungal growth and/or the toxin synthesis (DON)

Costs and Benefits of Stem Cell Research and Treatment: Media Presentation and Audience Understanding in Hungary

This study examined the press coverage and audience understanding of the costs and benefits of stem cell research/treatment in Hungary. A content analysis of five newspapers and a focus group study was conducted. The way participants talked about the costs and benefits in many aspects echoed the dominant framing of the issue in the press (medical benefits = main benefit, high expense of treatment = dominant negative aspect). Even though participants applied analogical reasoning to formulate some risks that were missing from the reporting on stem cells, many gaps of the media coverage were echoed in gaps in lay discussions

Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, \nobreak{$6\times 10^{19}$eV}. The anisotropy was measured by the fraction of arrival directions that are less than $3.1^\circ$ from the position of an active galactic nucleus within 75 Mpc (using the V\'eron-Cetty and V\'eron $12^{\rm th}$ catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is $(38^{+7}_{-6})$, compared with $21$ expected for isotropic cosmic rays. This is down from the early estimate of $(69^{+11}_{-13})$. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.Comment: Accepted for publication in Astroparticle Physics on 31 August 201

Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle Physic