92 research outputs found

    The Soluble Proteome of the Drosophila Antenna

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    The olfactory system of Drosophila melanogaster is one of the best characterized chemosensory systems. Identification of proteins contained in the third antennal segment, the main olfactory organ, has previously relied primarily on immunohistochemistry, and although such studies and in situ hybridization studies are informative, they focus generally on one or few gene products at a time, and quantification is difficult. In addition, purification of native proteins from the antenna is challenging because it is small and encased in a hard cuticle. Here, we describe a simple method for the large-scale detection of soluble proteins from the Drosophila antenna by chromatographic separation of tryptic peptides followed by tandem mass spectrometry with femtomole detection sensitivities. Examination of the identities of these proteins indicates that they originate both from the extracellular perilymph and from the cytoplasm of disrupted cells. We identified enzymes involved with intermediary metabolism, proteins associated with regulation of gene expression, nucleic acid metabolism and protein metabolism, proteins associated with microtubular transport, 8 odorant-binding proteins, protective enzymes associated with antibacterial defense and defense against oxidative damage, cuticular proteins, and proteins of unknown function, which represented about one-third of all soluble proteins. The procedure described here opens the way for precise quantification of any target protein in the Drosophila antenna and should be readily applicable to antennae from other insects

    Suppressed basal melting in the eastern Thwaites Glacier grounding zone

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    This work is from the MELT project, a component of the International Thwaites Glacier Collaboration (ITGC). Support from the National Science Foundation (NSF, grant no. 1739003) and the Natural Environment Research Council (NERC, grant no. NE/S006656/1). Logistics provided by NSF U.S. Antarctic Program and NERC British Antarctic Survey. The ship-based CTD data were supported by the ITGC TARSAN project (NERC grant nos. NE/S006419/1 and NE/S006591/1; NSF grant no. 1929991). ITGC contribution no. ITGC 047.Thwaites Glacier is one of the fastest-changing ice–ocean systems in Antarctica1,2,3. Much of the ice sheet within the catchment of Thwaites Glacier is grounded below sea level on bedrock that deepens inland4, making it susceptible to rapid and irreversible ice loss that could raise the global sea level by more than half a metre2,3,5. The rate and extent of ice loss, and whether it proceeds irreversibly, are set by the ocean conditions and basal melting within the grounding-zone region where Thwaites Glacier first goes afloat3,6, both of which are largely unknown. Here we show—using observations from a hot-water-drilled access hole—that the grounding zone of Thwaites Eastern Ice Shelf (TEIS) is characterized by a warm and highly stable water column with temperatures substantially higher than the in situ freezing point. Despite these warm conditions, low current speeds and strong density stratification in the ice–ocean boundary layer actively restrict the vertical mixing of heat towards the ice base7,8, resulting in strongly suppressed basal melting. Our results demonstrate that the canonical model of ice-shelf basal melting used to generate sea-level projections cannot reproduce observed melt rates beneath this critically important glacier, and that rapid and possibly unstable grounding-line retreat may be associated with relatively modest basal melt rates.Publisher PDFPeer reviewe

    Tax Evasion, Tax Avoidance and Tax Planning in Australia: The participation in mass-marketed tax avoidance schemes in the Pilbara region of Western Australia in the 1990s

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    This paper will examine the development of mass-marketed tax avoidance schemes in Australia. It will consider changes in approach to tax avoidance from the ‘bottom of the harbour’ schemes of the 1960s and 1970s to the mass-marketed tax avoidance schemes of the 1990s. It will examine the changing structure of tax avoidance from individually crafted tax avoidance structures designed by accountants and lawyers used by high wealth individuals to mass produced structures targeted at highly paid, and therefore highly taxed, blue collar workers in Australia’s mining industry in the 1990s. In the latter half of the twentieth century ‘unacceptable’ tax planning went from highly expensive, individually ‘tailor made’ structures afforded and used only by the very wealthy, to inexpensive replicated structures marketed to skilled and unskilled tradespeople and labourers. By 1998 over 42 000 Australian taxpayers were engaged in tax avoidance schemes with the highest proportion focussed in the mining regions of Western Australia. In the remote and inhospitable mining community of Pannawonica, which has one of the highest paid workforces in Australia, the Australian Taxation Office identified that as many as one in five taxpayers were engaged in a mass-marketed tax avoidance scheme. The paper will identify the causes of these changes, including the advent of the computerised information technology which permitted ‘mass production’ of business structures designed to exploit business incentives in the Australian taxation system in the 1990s. It will also set these developments within the broader context of the tax compliance culture prevailing in Australia and overseas during this period

    Alpha-Toxin Induces Programmed Cell Death of Human T cells, B cells, and Monocytes during USA300 Infection

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    This investigation examines the influence of alpha-toxin (Hla) during USA300 infection of human leukocytes. Survival of an USA300 isogenic deletion mutant of hla (USA300Δhla) in human blood was comparable to the parental wild-type strain and polymorphonuclear leukocyte (PMN) plasma membrane permeability caused by USA300 did not require Hla. Flow cytometry analysis of peripheral blood mononuclear cells (PBMCs) following infection by USA300, USA300Δhla, and USA300Δhla transformed with a plasmid over-expressing Hla (USA300Δhla Comp) demonstrated this toxin plays a significant role inducing plasma membrane permeability of CD14+, CD3+, and CD19+ PBMCs. Rapid plasma membrane permeability independent of Hla was observed for PMNs, CD14+ and CD19+ PBMCs following intoxication with USA300 supernatant while the majority of CD3+ PBMC plasma membrane permeability induced by USA300 required Hla. Addition of recombinant Hla to USA300Δhla supernatant rescued CD3+ and CD19+ PBMC plasma membrane permeability generated by USA300 supernatant. An observed delay in plasma membrane permeability caused by Hla in conjunction with Annexin V binding and ApoBrdU Tunel assays examining PBMCs intoxicated with recombinant Hla or infected with USA300, USA300Δhla, USA300Δhla Comp, and USA300ΔsaeR/S suggest Hla induces programmed cell death of monocytes, B cells, and T cells that results in plasma membrane permeability. Together these findings underscore the importance of Hla during S. aureus infection of human tissue and specifically demonstrate Hla activity during USA300 infection triggers programmed cell death of human monocytes, T cells and B cells that leads to plasma membrane permeability

    How to screen for non-adherence to antihypertensive therapy

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    The quality of assessment of non-adherence to treatment in hypertensive is poor. Within this review, we discuss the different methods used to assess adherence to blood-pressure-lowering medications in hypertension patients. Subjective reports such as physicians’ perceptions are inaccurate, and questionnaires completed by patients tend to overreport adherence and show a low diagnostic specificity. Indirect objective methods such as pharmacy database records can be useful, but they are limited by the robustness of the recorded data. Electronic medication monitoring devices are accurate but usually track adherence to only a single medication and can be expensive. Overall, the fundamental issue with indirect objective measures is that they do not fully confirm ingestion of antihypertensive medications. Detection of antihypertensive medications in body fluids using liquid chromatography–tandem mass spectrometry is currently, in our view, the most robust and clinically useful method to assess non-adherence to blood-pressure-lowering treatment. It is particularly helpful in patients presenting with resistant, refractory or uncontrolled hypertension despite the optimal therapy. We recommend using this diagnostic strategy to detect non-adherence alongside a no-blame approach tailoring support to address the perceptions (e.g. beliefs about the illness and treatment) and practicalities (e.g. capability and resources) influencing motivation and ability to adhere

    Suppressed basal melting in the eastern Thwaites Glacier grounding zone

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    Thwaites Glacier is one of the fastest-changing ice–ocean systems in Antarctica1,2,3. Much of the ice sheet within the catchment of Thwaites Glacier is grounded below sea level on bedrock that deepens inland4, making it susceptible to rapid and irreversible ice loss that could raise the global sea level by more than half a metre2,3,5. The rate and extent of ice loss, and whether it proceeds irreversibly, are set by the ocean conditions and basal melting within the grounding-zone region where Thwaites Glacier first goes afloat3,6, both of which are largely unknown. Here we show—using observations from a hot-water-drilled access hole—that the grounding zone of Thwaites Eastern Ice Shelf (TEIS) is characterized by a warm and highly stable water column with temperatures substantially higher than the in situ freezing point. Despite these warm conditions, low current speeds and strong density stratification in the ice–ocean boundary layer actively restrict the vertical mixing of heat towards the ice base7,8, resulting in strongly suppressed basal melting. Our results demonstrate that the canonical model of ice-shelf basal melting used to generate sea-level projections cannot reproduce observed melt rates beneath this critically important glacier, and that rapid and possibly unstable grounding-line retreat may be associated with relatively modest basal melt rates

    Co-regulation of a large and rapidly evolving repertoire of odorant receptor genes

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    The olfactory system meets niche- and species-specific demands by an accelerated evolution of its odorant receptor repertoires. In this review, we describe evolutionary processes that have shaped olfactory and vomeronasal receptor gene families in vertebrate genomes. We emphasize three important periods in the evolution of the olfactory system evident by comparative genomics: the adaptation to land in amphibian ancestors, the decline of olfaction in primates, and the delineation of putative pheromone receptors concurrent with rodent speciation. The rapid evolution of odorant receptor genes, the sheer size of the repertoire, as well as their wide distribution in the genome, presents a developmental challenge: how are these ever-changing odorant receptor repertoires coordinated within the olfactory system? A central organizing principle in olfaction is the specialization of sensory neurons resulting from each sensory neuron expressing only ~one odorant receptor allele. In this review, we also discuss this mutually exclusive expression of odorant receptor genes. We have considered several models to account for co-regulation of odorant receptor repertoires, as well as discussed a new hypothesis that invokes important epigenetic properties of the system

    NCAR/SPERR: Change license to Apache

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    <p>This is a patch release; the software license is changed to Apache-2.0.</p&gt
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