337 research outputs found

    Hot-water baths, biologicals and re-curing effects on rhizopus soft rot during sweetpotato packing

    Get PDF
    Rhizopus soft rot (RSR) caused by Rhizopus stolonifer is one of the most devastating postharvest diseases of sweetpotato. It causes greatest losses when sweetpotatoes are removed from storage, washed and packed for marketing. The disease has been managed effectively by prophylactic application of synthetic fungicides on the packing line. However, there is increasing demand for alternative management strategies that do not rely on prophylactic use of synthetic fungicides. While curing immediately after harvest is a standard industry practice, re-curing after storage is not widely practised for postharvest disease management. In this study, the use of hot-water baths, biocontrol agents and re-curing after storage were investigated as potential replacements for synthetic fungicides that are widely used during sweetpotato packing. Hot-water baths at 52 °C for 10–15 min immediately after inoculation reduced RSR incidence by as much as 75%, but increased susceptibility to post-treatment Rhizopus infection. The biological control product Bio-Save® (a.i. Pseudomonas syringae strain ESC-10), used in conjunction with a 4 min water bath at 52 °C, gave similar protection (1.2% RSR, t = −1.7, P = 0.514) as the industry standard treatment with dicloran. Re-curing for as little as 4 h after washing roots significantly reduced RSR and deserves further evaluation to optimize conditions and determine its influence on other postharvest diseases

    Prototheca bovis, a unicellular achlorophyllous trebouxiophyte green alga in the healthy human intestine

    Get PDF
    Introduction: Prototheca species are non-photosynthetic trebouxiophyte algae ubiquitously distributed in nature and can be found in sewage and soil. This microbial eukaryote causes human protothecosis in immunocompromised individuals. Thus, Prototheca presence in the stool of individuals without gastrointestinal symptoms has been reported only rarely. Hypothesis/Gap statement: There is an absence of detailed characterization of human Prototheca isolates. Aim: The aim of this study was to perform morphological and molecular characterization of Prototheca isolates obtained from human stool. Methodology: Prototheca was isolated from fecal samples of four individuals living in a rural area in Thailand. A combination of bioimaging along with molecular and bioinformatics tools was used to characterize the four strains. The growth rate was tested using four media and three temperature conditions. Phylogenetic analysis using the small subunit ribosomal RNA (SSU rRNA) and cytochrome b (cytb) was also performed. Results: Static and live microscopy demonstrated the various life stages of Prototheca and its major defining cellular characteristics. An optimized DNA extraction methodology that improves DNA yield is provided. Partial fragments of the SSU rRNA and cytb genes were obtained. Phylogenetic analysis placed all four strains in the clade with Prototheca bovis. More broadly, Prototheca was not monophyletic but split into at least two distinct clades instead. Conclusion: The results represent the first molecular characterization of Prototheca in Thailand. The study provides insight into transmission dynamics of the organism and potential caveats in estimating the global prevalence of Prototheca. These will spearhead further investigations on Prototheca occurrence in rural areas of both industrialized and developing nations

    Blastocystis colonization and associations with population parameters in Thai adults

    Get PDF
    Background: Blastocystis is a unicellular eukaryote commonly found in the intestinal tract of humans and other animals. The prevalence of Blastocystis has been investigated in both developed and developing countries, yet its occurrence and distribution in rural locations has been less studied. Herein, we aimed to examine the distribution of Blastocystis colonization in Thai adults representing background populations along a rural/peri-urban gradient, as well as associations between colonization and personal characteristics. Methodology: A total of 238 participants were recruited from rural and peri-urban areas situated in three provinces. The presence of Blastocystis in feces was evaluated using PCR and qPCR. Information on gender, age, region (province), rural/peri-urban location, and body mass index (BMI) was collected. Principal findings: The overall rate of Blastocystis carriage was 67.2%. Univariate analysis revealed significant associations between Blastocystis carriage and region (p<0.05), location (p<0.001) and age group (p<0.05). Logistic regression analysis revealed that rural/peri-urban location and BMI were significantly associated with Blastocystis carriage. Nine subtypes (ST1-ST7, ST10 and ST23) were identified with ST3, ST7 and ST1 as the most abundant ones, in this order. The greatest diversity of subtypes, in terms of numbers, was found in the middle aged group (nine subtypes), while the least diversity was found in the young adult and obese (three subtypes each) groups. Conclusions: This study increases the understanding of the epidemiology of Blastocystis colonization and its association with population parameters and characteristics in middle-income countries

    Particle-type dependence of azimuthal anisotropy and nuclear modification of particle production in Au+Au collisions at s(NN)**(1/2) = 200-GeV

    Get PDF
    We present STAR measurements of the azimuthal anisotropy parameter v2v_2 and the binary-collision scaled centrality ratio RCPR_{CP} for kaons and lambdas (Λ+Λˉ\Lambda+\bar{\Lambda}) at mid-rapidity in Au+Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV. In combination, the v2v_2 and RCPR_{CP} particle-type dependencies contradict expectations from partonic energy loss followed by standard fragmentation in vacuum. We establish pT5p_T \approx 5 GeV/c as the value where the centrality dependent baryon enhancement ends. The KS0K_S^0 and Λ+Λˉ\Lambda+\bar{\Lambda} v2v_2 values are consistent with expectations of constituent-quark-number scaling from models of hadron fromation by parton coalescence or recombination.Comment: 6 pages, 4 figures, 1 table. As published in PRL on Feb. 2, 2004; Significant revisions have been made to the text and color has been added to plot

    Pion-Xi correlations in Au-Au collisions at STAR

    Full text link
    We present pion-Xi correlation analysis in Au-Au collisions at sqrt(s_NN)= 200 GeV and sqrt(s_NN) = 62.4 GeV, performed using the STAR detector at RHIC. A Xi*(1530) resonance signal is observed for the first time in Au-Au collisions. Experimental data are compared with theoretical predictions. The strength of the Xi* peak is reproduced in the correlation function assuming that pions and Xis emerge from a system in collective expansion.Comment: To appear in the proceedings of 18th Nuclear Physics Division Conference of the EPS (NPDC18),Prague, 23.8.-29.8. 200

    Rapidity and centrality dependence of proton and antiproton production from 197Au + 197Au collisions at √SNN = 130 GeV

    Get PDF
    We report on the rapidity and centrality dependence of proton and antiproton transverse mass distributions from 197Au + 197Au collisions at sqrt[sNN ]=130 GeV as measured by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). Our results are from the rapidity and transverse momentum range of |y| <0.5 and 0.35< pt <1.00 GeV/c . For both protons and antiprotons, transverse mass distributions become more convex from peripheral to central collisions demonstrating characteristics of collective expansion. The measured rapidity distributions and the mean transverse momenta versus rapidity are flat within |y| <0.5 . Comparisons of our data with results from model calculations indicate that in order to obtain a consistent picture of the proton (antiproton) yields and transverse mass distributions the possibility of prehadronic collective expansion may have to be taken into account

    Azimuthally sensitive Hanbury Brown-Twiss interferometry in Au+Au collisions at sqrt(s_{NN}) = 200 GeV

    Get PDF
    We present the results of a systematic study of the shape of the pion distribution in coordinate space at freeze-out in Au+Au collisions at RHIC using two-pion Hanbury Brown-Twiss (HBT) interferometry. Oscillations of the extracted HBT radii vs. emission angle indicate sources elongated perpendicular to the reaction plane. The results indicate that the pressure and expansion time of the collision system are not sufficient to completely quench its initial shape.Comment: 6 pages, 4 figures, published versio

    Evidence from d+Au measurements for final-state suppression of high pTp_T hadrons in Au+Au collisions at RHIC

    Full text link
    We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions of charged hadrons at high transverse momentum (high pTp_T) in minimum bias and central d+Au collisions at sNN\sqrt{s_{NN}}=200 GeV. The inclusive yield is enhanced in d+Au collisions relative to binary-scaled p+p collisions, while the two-particle azimuthal distributions are very similar to those observed in p+p collisions. These results demonstrate that the strong suppression of the inclusive yield and back-to-back correlations at high pTp_T previously observed in central Au+Au collisions are due to final-state interactions with the dense medium generated in such collisions.Comment: Final journal version. Data tables for figures may be downloaded from the STAR home page: http://www.star.bnl.gov --> Publications --> Access to STAR published dat
    corecore