92 research outputs found

    The rph1 Gene Is a Common Contributor to the Evolution of Phosphine Resistance in Independent Field Isolates of Rhyzopertha Dominica

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    Phosphine is the only economically viable fumigant for routine control of insect pests of stored food products, but its continued use is now threatened by the world-wide emergence of high-level resistance in key pest species. Phosphine has a unique mode of action relative to well-characterised contact pesticides. Similarly, the selective pressures that lead to resistance against field sprays differ dramatically from those encountered during fumigation. The consequences of these differences have not been investigated adequately. We determine the genetic basis of phosphine resistance in Rhyzopertha dominica strains collected from New South Wales and South Australia and compare this with resistance in a previously characterised strain from Queensland. The resistance levels range from 225 and 100 times the baseline response of a sensitive reference strain. Moreover, molecular and phenotypic data indicate that high-level resistance was derived independently in each of the three widely separated geographical regions. Despite the independent origins, resistance was due to two interacting genes in each instance. Furthermore, complementation analysis reveals that all three strains contain an incompletely recessive resistance allele of the autosomal rph1 resistance gene. This is particularly noteworthy as a resistance allele at rph1 was previously proposed to be a necessary first step in the evolution of high-level resistance. Despite the capacity of phosphine to disrupt a wide range of enzymes and biological processes, it is remarkable that the initial step in the selection of resistance is so similar in isolated outbreaks

    Glycan labeling strategies and their use in identification and quantification

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    Most methods for the analysis of oligosaccharides from biological sources require a glycan derivatization step: glycans may be derivatized to introduce a chromophore or fluorophore, facilitating detection after chromatographic or electrophoretic separation. Derivatization can also be applied to link charged or hydrophobic groups at the reducing end to enhance glycan separation and mass-spectrometric detection. Moreover, derivatization steps such as permethylation aim at stabilizing sialic acid residues, enhancing mass-spectrometric sensitivity, and supporting detailed structural characterization by (tandem) mass spectrometry. Finally, many glycan labels serve as a linker for oligosaccharide attachment to surfaces or carrier proteins, thereby allowing interaction studies with carbohydrate-binding proteins. In this review, various aspects of glycan labeling, separation, and detection strategies are discussed

    Experimental investigation of the characteristics of an NO x

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    A study on thermal decomposition of fuels and NO x

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    Utilization of High-Resolution Boundary Layer Radar and Wavelet to Detect Microscale Downdraft-Updraft Combination

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    High-resolution boundary layer radar (BI, R) and wavelet are utilized to observe microscale downdraft-updraft combinations. High-resolution BLR can observe thermal activity that pushed the stable layer. During this thermal, a combination of downdraft-updraft was also observed. A detailed observation of this combination was conducted in this study. Using a 1-dimensional continuous wavelet transform with Paul wavelet, we could quantify this downdraft-updraft combination based on the height and period. Using this quantification and wavelet variance in different weather conditions, we showed the essential period from 0 to 0.25 min, 2 to 4 min, and 4 to 8 min of this microscale downdraft-updraft combination

    Wavelet Analysis of Thermal Activity and Cloud Initiation based on Boundary Layer Radar and Time Lapse Camera Observation

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    This study aims at observing cumulus clouds generated in the boundary layer and to investigate relationship between the cumulus clouds and local thermals. Individual cumulus clouds generated in the boundary layer were observed by a time-lapse camera. Vertical air velocity measured by a Boundary Layer Radar (BLR) was used to observe local thermals. The BLR was collocated with the time-lapse camera. Wavelet coherence was used to quantify the relationship between the two variables. We found that an upward air motion was observed ahead of a cumulus cloud development below 900 m height within 27 events of an individual cumulus cloud. The phase classification showed that 40.7 % of the local thermal event in the boundary layer region impacted the cumulus cloud development. The scale period of these local thermals varied from 0.5 until 8 min
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