998 research outputs found

    An Asian Origin of Virulent Aeromonas Hydrophila Responsible for Disease Epidemics in United States-Farmed Catfish

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    Unlabelled: Since 2009, catfish farming in the southeastern United States has been severely impacted by a highly virulent and clonal population of Aeromonas hydrophila causing motile Aeromonas septicemia (MAS) in catfish. The possible origin of this newly emerged highly virulent A. hydrophila strain is unknown. In this study, we show using whole-genome sequencing and comparative genomics that A. hydrophila isolates from diseased grass carp in China and catfish in the United States have highly similar genomes. Our phylogenomic analyses suggest that U.S. catfish isolates emerged from A. hydrophila populations of Asian origin. Furthermore, we identified an A. hydrophila strain isolated in 2004 from a diseased catfish in Mississippi, prior to the onset of the major epidemic outbreaks in Alabama starting in 2009, with genomic characteristics that are intermediate between those of the Asian and Alabama fish isolates. Investigation of A. hydrophila strain virulence demonstrated that the isolate from the U.S. catfish epidemic is significantly more virulent to both channel catfish and grass carp than is the Chinese carp isolate. This study implicates the importation of fish or fishery products into the United States as the source of highly virulent A. hydrophila that has caused severe epidemic outbreaks in United States-farmed catfish and further demonstrates the potential for invasive animal species to disseminate bacterial pathogens worldwide. Importance: Catfish aquaculture farming in the southeastern United States has been severely affected by the emergence of virulent Aeromonas hydrophila responsible for epidemic disease outbreaks, resulting in the death of over 10 million pounds of catfish. Because the origin of this newly emerged A. hydrophila strain is unknown, this study used a comparative genomics approach to conduct a phylogenomic analysis of A. hydrophila isolates obtained from the United States and Asia. Our results suggest that the virulent isolates from United States-farmed catfish have a recent common ancestor with A. hydrophila isolates from diseased Asian carp. We have also observed that an Asian carp isolate, like recent U.S. catfish isolates, is virulent in catfish. The results from this study suggest that the highly virulent U.S. epidemic isolates emerged from an Asian source and provide another example of the threat that invasive species pose in the dissemination of bacterial pathogens. (Copyright © 2014 Hossain et al.

    Phenotyping of mungbean (Vigna radiata L.) genotypes against salt stress and assessment of variability for yield and yield attributing traits

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    Salt tolerance is a complex polygenic trait that is genotype specific and tolerance can depend upon a plants developmental stage. To evaluate reproductive stage specific salt tolerance as well as investigate the inherent variability of mungbean (Vigna radiata L.) genotypes with respect to seed yields and yield-related traits, a pot culture experiment was conducted using 26 mungbean genotypes and exposure to salt stress (EC = 8.0 dS/m) applied at the reproductive stage, just before the opening of the first flowers. The experiment involved maintaining 100% field capacity for three weeks and used a randomized complete block design with three replicates. Data were collected, included days to maturity, plant height (cm), number of pod-bearing branches per plant, number of pods per plant, pod length (cm), number of seeds per pod, 100-seed weight (g) and seed yield per plant (g). Salt stress led to a significant (p<0.001) decrease in seed yield per plant, with yields of the genotypes BMX 11116, BMX 11176, BMX 11140, BMX 11111 and BMX 11163 being the least impacted by exposure to salt. Principal component analysis revealed that the first two components explained 63.5% of the total variation among the mungbean genotypes. Seed yield per plant showed a significant positive correlation with days to maturity, number of pod-bearing branches per plant, number of pods per plant, pod length (cm), number of seeds per pod, and 100-seed weight (g). Cluster analysis grouped the 26 genotypes into five distinct clusters, where the tolerant genotypes placed in cluster I. Based on their stress tolerance indices BARI Mung-6, BMX 11176, BMX 11116, and BMX 11140 were categorized as tolerant genotypes, were selected for further study under direct field conditions and are recommended for the genetic improvement of salt stress tolerance in mungbean

    Efficacy and Safety of Methotrexate in Articular and Cutaneous Manifestations of systemic Lupus Erythematosus

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    Aim:  A prospective open-label study comparing the efficacy and safety of methotrexate (MTX) and chloroquine (CQ) in articular and cutaneous manifestations of systemic lupus erythematosus (SLE). Methods:  Consecutive SLE patients were randomly assigned to either 10 mg MTX weekly or 150 mg CQ daily during 24 weeks. Outcome measures were: numbers of swollen and tender joints, duration of morning stiffness, visual analog scale (VAS) for articular pain, physician global assessment index, patient global assessment index, SLE Disease Activity Index (SLEDAI), disappearance of skin rash and erythrocyte sedimentation rate (ESR). Results:  Forty-one patients consented to participate, 15 were allocated in the MTX group and 26 in the CQ group. Two patients on MTX dropped out due to side-effects and two in the CQ group, one due to side-effects and one due to inefficacy. Baseline demographic, clinical and laboratory parameters of the two groups were nearly identical. In both groups the clinical and laboratory parameters improved significantly over 24 weeks, except the ESR in the MTX group. The results of the outcome measures at the end of the trial did not differ significantly between the two groups, except morning stiffness (P < 0.05 in favor of the MTX group) and ESR (P < 0.01 in favor of the CQ group). Rise of serum alanine aminotransferase was observed in two cases in the MTX group and in none in the CQ group. Conclusion:  Low-dose MTX appears to be as effective as CQ in patients with articular and cutaneous manifestations of SLE, having an acceptable toxicity profile. Results of this prospective study need to be confirmed in a larger study

    Muscle spindles provide servo-assistance to jaw-closing muscles for chewing hard foods

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    The fundamental pattern of chewing induced by the network of neurons called central pattern generator has been reported to be modified by the information arising from the various oro-facial sensory receptors including muscle spindles of jaw closing muscles. The cell bodies of primary afferent neurons from these muscle spindles lie in mesencephalic trigeminal nucleus (MTN) in the brainstem. The aim of the study was to understand whether muscle spindles from jaw-closing muscles play any role in hard food chewing. Single neuronal discharge of muscle spindle afferents was recorded from the MTN simultaneous with jaw-movement and electromyograpic (EMG) activities of the left masseter (jaw-closing) muscle during chewing soft and hard foods (apple and pellet) in awake rabbits. Ten consecutive chewing cycles were taken for analysis. Discharge of nineteen muscle spindles from seven rabbits was successfully recorded. Muscle-spindle discharge was significantly higher during the closing phase of jaw-movement for the hard food chewing than for the soft food. The jaw-closing muscle EMG activity was significantly higher during hard food chewing compared to soft food. The spindle discharge was higher when the masseter muscle activity was greater for chewing hard food. Significant positive (r=0.822, p=<0.001) correlation was found between the difference of muscle activity between apple and pellet and the difference of spindle discharge between apple and pellet. Above findings suggest that the increase of spindle discharge during hard food chewing may play a role for facilitating jaw-closing muscle activities and thereby provides servo-assistance to jaw-closing muscles to compensate the hardness of food

    Profiling of Phytochemicals in Tissues from Sclerocarya birrea by HPLC-MS and Their Link with Antioxidant Activity

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    peer-reviewedHigh performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed to investigate the differences in phytochemicals in roots, bark, and leaf of Sclerocarya birrea (marula) for methanol and water extracts that exhibited the best antioxidant activities. As many as 36 compounds were observed in the extracts of these tissues of which 27 phenolic compounds were tentatively identified. The HPLC-MS/MS results showed flavonoid glycosides were prominent in leaf extracts while the galloylated tannins were largely in bark and root extracts. Four flavonoid glycosides that were reported for the first time in the marula leaf have been identified. The HPLC-MS/MS studies also illustrated different degrees (highest degree = 3) of oligomerisation and galloylation of tannins in the bark and root extracts

    Investigaciones fitoquímicas y biológicas de extractos metanólicos de hojas de Ziziphus mauritiana Lam

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    Siete compuestos fueron aislados del extracto metanólico de hojas de Ziziphus mauritiana. Las estructuras de los compuestos aislados fueron identificadas como γ-fagarina (1), β-sitosterol (2), estigmasterol (3), α-amirina (4), lupeol (5), β-amirina (6) y betulina (7 ) por medio de extensivos estudios espectroscópicos y por co-TLC con muestras auténticas. Este es el primer informe de aislamiento de los compuestos 1-7 a partir de esta especie vegetal. Los extractos de las hojas fueron investigados por efectos trombolíticos, estabilizadores de membrana, antimicrobianos, antidiarreicos y potenciales analgésicos junto a la propiedad de inducir sueño en el modelo animal. Las actividades trombolíticos y la estabilización de la membrana se evaluaron mediante el uso de eritrocitos humanos comparando con estreptoquinasa estándar y el ácido acetilsalicílico, respectivamente. El extracto metanólico redujo la frecuencia de las heces diarreicas en comparación con el estándar de loperamida. En la inducción por aceite de ricino de diarrea en ratones, se observó una disminución dosis dependiente de los tránsitos gastrointestinales. En el método del coletazo producido por calor radiante, el extracto metabólico mostró una actividad antinociceptiva moderada, en comparación con la morfina estándar

    Detailed Performance Loss Analysis of Silicon Solar Cells using High-Throughput Metrology Methods

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    In this work, novel, high-throughput metrology methods are used to perform a detailed performance loss analysis of approximately 400 industrial crystalline silicon solar cells, all coming from the same production line. The characterization sequence includes a non-destructive transfer length method (TLM) measurement technique featuring circular TLM structures hidden within the busbar region of the cells. It also includes a very fast external quantum efficiency and reflectance measurement technique. More traditional measurements, like illuminated current-voltage, Suns-VOC, and photoluminescence imaging are also used to carry out the loss analysis. The variance of the individual loss parameters and their impact on cell performance are investigated and quantified for this large group of industrial solar cells. Some important correlations between the measured loss parameters are found. The nature of these distributions and correlations provide important insights about loss mechanisms in a cell and help prioritize efforts to optimize the performance of the production line.Comment: 5 pages, 6 figures, conferenc
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