110 research outputs found

    Isolation and pathogenicity of Phytophthora species from declining Rubus anglocandicans

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    Rubus anglocandicans is the most widespread and abundant blackberry species within the European blackberry (Rubus fruticosus) aggregate in Western Australia (WA). European blackberry is also one of the 32 Weeds of National Significance in Australia. A disease recorded as 'blackberry decline' was first observed in some blackberry sites in WA in 2006. A disease survey was conducted in the Manjimup-Pemberton region along the Warren and Donnelly River catchments in WA between 2010 and 2012. Phytophthora amnicola, P. bilorbang, P. cryptogea, P. inundata, P. litoralis, P. multivora, P. taxon personii, P. thermophila and a P. thermophila × amnicola hybrid were recovered from declining and adjacent decline-free sites, as well as from streams and rivers. Phytophthora cinnamomi was isolated from dying Banksia and Eucalyptus species from two non-decline sites. Of these species, P. bilorbang and P. cryptogea were more pathogenic than the others in under-bark inoculations using excised stems (primocanes), in planta primocane inoculations in blackberry growing wild in native forest stands, and in glasshouse pot trials. It was concluded that blackberry decline is a complex syndrome and Phytophthora species, in particular P. bilorbang and P. cryptogea, together with temporary inundation, are major biotic and abiotic factors contributing to blackberry decline

    In vitro and in vivo antifungal properties of silver nanoparticles against Rhizoctonia solani, a common agent of rice sheath blight disease

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    Sheath blight disease in rice has caused major crop losses worldwide. Managing the causal agent of disease Rhizoctonia solani Kühn is difficult because of its broad host range and formation of sclerotia which can survive in harsh environmental conditions; therefore developing innovative disease management methods without application of hazardous chemicals has been considered as the main concern to maintain sustainable agriculture. This presented research has revealed the negative impact of Silver nanoparticles (SNPs) on R. solani and disease progress both in vitro and in vivo. The adverse effects of the SNPs on R. solani are significantly dependent on the quantity of SNPs, sprayed at different concentrations in vitro. The highest inhibition level against sclerotia formation and mycelia growth are 92 and 85%, respectively, at a SNPs concentration of 50 ppm. In vivo glasshouse experiments also showed that SNPs at the same concentration favorably affects both the fresh and dry weight of rice plants with a remarkable suppressive effect on the lesion development in leaves

    Gene Diversity of Trichomonas vaginalis Isolates

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    Background: Trichomonas vaginalis is protozoan parasite responsible for trichomoniasis and is more common in high-risk behavior group such as prostitute individuals. Interest in trichomoni­asis is due to increase one's susceptibility to viruses such as herpes, human papillomavirus and HIV. The aim of this study was to find genotypic differences between the isolates.Methods: Forty isolates from prisoners' women in Tehran province were used in this study. The random amplified polymorphic DNA (RAPD) technique was used to determine genetic differ­ences among isolates and was correlated with patient's records. By each primer the banding pat­tern size of each isolates was scored (bp), genetic differences were studied, and the genealogical tree was constructed by using NTSYS software program and UPGMA method.Results: The least number of bands were seen by using primer OPD8 and the most by using OPD3. Results showed no significant difference in isolates from different geographical areas in Iran. By using primer OPD1 specific amplified fragment with length 1300 base pair were found in only 8 isolates. All these isolates were belonged to addicted women; however, six belonged to asymptomatic patients and two to symptomatic ones.Conclusion: There was not much genetic diversity in T vaginalis isolates from three different geo­graphical areas

    Evaluation of the effects of morphine consumption during lactation period on learning and memory of rat�s offspring

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    Background and Aim: The frequent use of opioids changes function and plasticity of neural circuits. Exposing the immature nervous system to opioids can have deeper and more extensive impacts. The aim of this study was to investigate the effects of morphine consumption during lactation period on learning and memory of rats offspring. Material and Methods: This experimental study included 40 male Wistar rats with age range of 45-50 days. Animals were divided into control group (CO) and 3 experimental groups of rats whose mothers had received subcutaneous injections of 5 (M5), 10 (M10) or 20 (M20) mg/kg morphine every 12 hours during lactation period. Spatial learning was evaluated by Morris water maze (MWM) on 4 consecutive days (4 trials/day). Spatial memory retrieval was also evaluated on the last day. Results: Our results indicated that the rats whose mothers had received morphine during lactation period spent more time and traveled more distance to find the hidden platform than the controls in the learning stage. These differences were statistically significant when doses of 10 and 20 mg/kg morphine (P<0.001) were used. Also, they spent less time and passed less distance in the target quadrant in probe trial (P<0.001). Conclusion: Morphine consumption during lactation period impairs spatial learning and memory of the rats' offspring in a dose dependent manner. © 2018, Kurdistan University of Medical Sciences. All rights reserved

    An Evaluation of the Effect of Deprivation of Maternal Care on LTP Induction in Neurons of Hippocampal CA1 Region in Morphine-Dependent Rats

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    BACKGROUND AND OBJECTIVE: Deprivation of maternal care as a stressor causes disruption in cognitive and neurochemical activities of the brain. The aim of this study was to evaluation the effect of deprivation of maternal care on LTP induction in neurons of hippocampal CA1 region in morphine-dependent rats. METHODS: This experimental study was conducted among 40 45-day-old male rats in control group, morphine-dependent group, and 3 groups of rats that were deprived of treatment for one, two and three weeks after birth for 3 hours daily. Except for the control group, the rest of the groups received 10 mg/kg body weight morphine sulfate subcutaneously every 12 hours for 10 days. On the eleventh day, the symptoms of deprivation syndrome were investigated by the Gellert-Holtzman method, and on the following day, the synaptic plasticity of neurons in CA1 region was studied. FINDINGS: The Gellert-Holtzman score in the morphine-dependent group was 14.98±4.16 and increased to 31.79±5.12 in the group that was deprived of maternal treatment for 3 weeks (p<0.001). Although morphine dependence did not affect basic responses of CA1 region neurons and LTP induction, deprivation of maternal care reduced the range of basic responses from 1.01±0.04 in the morphine-dependent group to 0.68±0.09 mV in the group that was deprived of maternal care for 3 weeks (p<0.001) and prevented LTP induction (p<0.001) in a time-dependent manner. CONCLUSION: The results of the study showed that deprivation of maternal care undermines the postsynaptic potential of the hippocampal CA1 region following morphine administration and disrupts the synaptic plasticity of the neurons in this region

    Behavioral and electrophysiological aspects of cognition in neonate rats lactated by morphine addicted mothers

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    Objective(s): In addition to genetic factors, environmental phenomena during postnatal age highly affect development and, in turn, function of the brain. The present work evaluates if morphine consumption during lactation period influences the spatial performances and synaptic plasticity in rats at neonatal period of age. Materials and Methods: Three groups of mothers were subcutaneously administered by 5 (M5), 10 (M10) or 20 (M20) mg/kg morphine every 12 hours during the lactation period. At 45 days old, their offspring were introduced to Morris water maze for assessment of spatial learning and memory. Basic field excitatory post-synaptic potentials (fEPSPs) were recorded in the CA1 area of hippocampus and, then, long term potentiation (LTP) was induced by tetanic stimulation. Results: We found that the M10 and M20 rats spent more time and traveled longer distance to find the hidden platform of maze when compared to the control animals (P<0.05 for all comparisons). Similarly, these two morphine-exposed groups were inferior in the memory consolidation compared to their control counterparts. Comparing control and M20 rats revealed that morphine exposure decreases the mean amplitude and slope 10-90 of fEPSPs about 30 percent (P<0.001 for both comparisons) and inhibits the LTP induction in the CA1 area circuits. Conclusion: The present study provides behavioral and electrophysiological proofs for negative effect of morphine on the hippocampal-related function in the neonatally morphine-exposed rats. © 2019, Mashhad University of Medical Sciences. All rights reserved

    Interaction between Injection Points during Hydraulic Fracturing

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    We present a model of the hydraulic fracturing of heterogeneous poroelastic media. The formalism is an effective continuum model that captures the coupled dynamics of the fluid pressure and the fractured rock matrix and models both the tensile and shear failure of the rock. As an application of the formalism, we study the geomechanical stress interaction between two injection points during hydraulic fracturing (hydrofracking) and how this interaction influences the fracturing process. For injection points that are separated by less than a critical correlation length, we find that the fracturing process around each point is strongly correlated with the position of the neighboring point. The magnitude of the correlation length depends on the degree of heterogeneity of the rock and is on the order of 30-45 m for rocks with low permeabilities. In the strongly correlated regime, we predict a novel effective fracture-force that attracts the fractures toward the neighboring injection point.Comment: Submitte

    Rayleigh-Bénard convection of Casson fluids

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    This study aims at investigating numerically the Rayleigh-Bénard Convection (RBC) in viscoplastic fluids. A Casson fluid is considered in a bidimensional square cavity heated from below. The effects of the dimensionless yield stress, the Bingham number Bn, on the heat transfer and motion is investigated in the range 5.10^3 < Ra < 10^5 for the Rayleigh number and Pr = 10, 100, 1000 for the Prandtl number. One shows that the yield stress has a stabilizing effect, reducing the convection intensity. Above a certain value of Bnmax , the convection does not occur and the heat transfer is only due to conduction. For moderate Bn values, truly unyielded regions are located in the center of the cavity; their areas grow with increasing Bingham number and invade the whole cavity at the threshold value Bnmax
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