678 research outputs found
Host Plant Feeding Preferences of the Adult Asiatic Garden Beetle, Maladera castanea Arrow (Coleoptera:Scarabaeidae)
The Asiatic garden beetle (AGB), Maladera castanea Arrow, is an invasive pest of crops, ornamentals, and turfgrass that has been minimally studied since the 1930s. Experiments were performed in 2011 and 2012 to investigate adult AGB feeding preferences and seasonality in Connecticut, with the goal of supporting informed planting and monitoring decisions. A common garden field experiment involved counting beetles on three cultivars each of basil, beet, carrot, eggplant, kohlrabi, parsnip, hot pepper, sweet pepper, and turnip. A no-choice laboratory experiment produced values of mass and area of leaf disks consumed. This included the same basil, beet, and kohlrabi varieties in 2011, and elderberry, arrowwood viburnum, green ash, red maple, sugar maple, and American sweetgum in 2012. Counts of beetles collected in light traps were performed throughout each field season.
Basil harbored the most AGBs in the field experiment in 2011 and 2012, and was most consumed in the laboratory experiment using edibles in 2012. However, the 2011 laboratory mass data showed that beets were more consumed than kohlrabi, and basil was consumed equally to beets and kohlrabi. In the 2011 field experiment, ‘Mexican Spice’ was preferred over ‘Lemon’ basil. Red maple was significantly more consumed than sugar maple in the laboratory study of ornamentals. In 2012, the first AGB adults were caught on June 20. Peak populations of adult AGBs in Connecticut occurred from mid-July to late August. This study has developed methods and outlined further lines of research on the AGB
Small-scale patterns and processes in a soft-substratum, intertidal community
Experimental manipulations and direct observations were combined to study small-scale dispersion patterns and their causes in an intertidal sand-flat community numerically dominated by sessile and sedentary tube dwellers. Individuals of several species exhibited gregariousness at scales as small as one centimeter. Experiments in which needles were placed in sediments to simulate animal tubes suggested that organisms are affected by patterns of flow which change over distances of several millimeters to a centimeter
Flow disruption by an animal-tube mimic affects sediment bacterial colonization
Simple flume experiments demonstrate that local flow perturbations by a protruding animal-tube mimic can cause a significant increase in bacterial colonization at the sediment-seawater interface. The occurrence and extent of this increase depend on properties of the viscous sublayer adjoining the bed—specifically, its spatial and temporal continuity, and its thickness relative to tube height. In the field homologous tube effects on bacterial colonization and abundances are likely to be common. These effects are postulated to be important to larval recruitment, community composition, the nutrition of deposit feeders, and sediment dynamics
Larval settlement in turbulent pipe flows
In two experiments, larval settlement was studied within a series of pipes, each containing steady, turbulent, flowing seawater. The study was designed to determine effects of flow (speed, turbulence intensity and wall shear stress) and surface orientation on rates of settlement of larvae of various taxa, and to relate variability in patterns of settlement among orientations and flows to the concomitant variability expected in rates of larval supply or delivery to the pipe walls. Patterns of settlement of all five taxa (the barnacle Balanus spp., the mussel Mytilus trossulus, the serpulid polychaete Pseudochitinopoma occidentalis, the cyclostome bryozoan Tubulipora sp., and the terebellid polychaete Eupolymnia heterobranchia) generally conformed to predicted patterns of larval supply to pipe walls (the larval transport flux). Within each taxon results were consistent in the two experiments. For these taxa, the transport fluxes that most closely matched observed settlement fluxes were predicted by assuming that larvae exhibited average speeds of advection (by swimming or sinking) of comparatively low magnitude. These best-fit larval speeds are consistent with results from previous studies of larval swimming. However, some results indicate that settlement patterns also were affected significantly by processes operating after larval contact with pipe walls. In several instances settlement patterns exhibited a strong and significant effect of wall orientation that varied in intensity with flow speed in a manner not predictable from expected patterns of larval supply. The probable causes for this effect and statistical interaction vary among taxa, but in all cases involve consideration of the habitat, behavior or success of the post-settlement, benthic individual
Stratospheric dynamics and transport studies
A three dimensional General Circulation Model/Transport Model is used to simulate stratospheric circulation and constituent distributions. Model simulations are analyzed to interpret radiative, chemical, and dynamical processes and their mutual interactions. Concurrent complementary studies are conducted using both global satellite data and other appropriate data. Comparisons of model simulations and data analysis studies are used to aid in understanding stratospheric dynamics and transport processes and to assess the validity of current theory and models
Numerical modeling of larval settlement in turbulent bottom boundary layers
A time-dependent model of a tidal or wave bottom boundary layer has been developed to quantitatively evaluate the relative influences of vertical advection, turbulent mixing and shear, and near-bed behavior on settlement of planktonic larvae of benthic animals. The settlement behavior of larvae is modeled with a simple flux condition at the bed. This allows full time dependence to be included when determining settlement rates. For tidal oscillations, the model predicts that most settlement will occur at and near periods of slack water, whereas comparatively little settlement will occur during periods of stronger flow. In contrast, there should be little temporal variability in settlement rates associated with short-period wind waves. If larvae exhibit a relatively weak propensity to settle, then the settlement flux is small compared to the advective/turbulent flux of larvae supplied from higher in the water column to regions near the bed. In this case, a description of probability of settlement and a quasi-steady state suspension model fully describe the system. In contrast, when larvae exhibit a high settlement propensity, then the settlement flux is potentially larger than the advective/turbulent flux and the system is controlled by the hydrodynamic supply of larvae to the near-bed region. In this case, net settlement is governed primarily by larval fall velocity (a composite of gravitational sinking plus swimming) and turbulent shear stress. The ecological systems which are controlled by animal behavior or by physical processes may thus be identified by estimates of relatively simple parameters describing these fluxes
Sediment destabilization by animal tubes
Laboratory flume ex periments we re conducted in order to test the influence on sediment e rodibility of varying densities of the tube-building polychaete worm Owenia fusiformis. Experiments were performed on isolated individuals, in order to measure approximate spatial limits of isolated tube effects, and on arrays of individuals at densities reported previously to be associated with stable beds...
Biochemical detection of Aβ isoforms: implications for pathogenesis, diagnosis, and treatment of Alzheimer’s disease
AbstractPrior to the identification of the various abnormal proteins deposited as fibrillar aggregates in the Alzheimer’s disease (AD) brain, there was tremendous controversy over the importance of the various lesions with respect to primacy in the pathology of AD. Nevertheless, based on analogy to systemic amyloidosis, many investigators believed that the amyloid deposits in AD played a causal role and that characterization of these deposits would hold the key to understanding this complex disease. Indeed, in retrospect, it was the initial biochemical purifications of the ∼4 kDa amyloid β-peptide (Aβ) from amyloid deposits in the mid 1980s that launched a new era of AD research (Glenner and Wong, Biochem. Biophys. Res. Commun. 122 (1984) 1121–1135; Wong et al., Proc. Natl. Acad Sci. USA 82 (1985) 8729–8732; and Masters et al., Proc. Natl. Acad Sci. USA 82 (1985) 4245–4249). Subsequent studies of the biology of Aβ together with genetic studies of AD have all supported the hypothesis that altered Aβ metabolism leading to aggregation plays a causal role in AD. Although there remains controversy as to whether Aβ deposited as classic amyloid or a smaller, aggregated, form causes AD, the relevance of studying the amyloid deposits has certainly been proven. Despite the significant advances in our understanding of the role of Aβ in AD pathogenesis, many important aspects of Aβ biology remain a mystery. This review will highlight those aspects of Aβ biology that have led to our increased understanding of the pathogenesis of AD as well as areas which warrant additional study
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Disrupted CXCR2 Signaling in Oligodendroglia Lineage Cells Enhances Myelin Repair in a Viral Model of Multiple Sclerosis.
CXCR2 is a chemokine receptor expressed on oligodendroglia that has been implicated in the pathogenesis of neuroinflammatory demyelinating diseases as well as enhancement of the migration, proliferation, and myelin production by oligodendroglia. Using an inducible proteolipid protein (Plp) promoter-driven Cre-loxP recombination system, we were able to assess how timed ablation of Cxcr2 in oligodendroglia affected disease following intracranial infection with the neurotropic JHM strain of mouse hepatitis virus (JHMV). Generation of Plp-Cre-ER(T)::Cxcr2flox/flox transgenic mice (termed Cxcr2-CKO mice) allows for Cxcr2 to be silenced in oligodendrocytes in adult mice following treatment with tamoxifen. Ablation of oligodendroglia Cxcr2 did not influence clinical severity in response to intracranial infection with JHMV. Infiltration of activated T cells or myeloid cells into the central nervous system (CNS) was not affected, nor was the ability to control viral infection. In addition, the severity of demyelination was similar between tamoxifen-treated mice and vehicle-treated controls. Notably, deletion of Cxcr2 resulted in increased remyelination, as assessed by g-ratio (the ratio of the inner axonal diameter to the total outer fiber diameter) calculation, compared to that in vehicle-treated control mice. Collectively, our findings argue that CXCR2 signaling in oligodendroglia is dispensable with regard to contributing to neuroinflammation, but its deletion enhances remyelination in a preclinical model of the human demyelinating disease multiple sclerosis (MS).IMPORTANCE Signaling through the chemokine receptor CXCR2 in oligodendroglia is important for developmental myelination in rodents, while chemical inhibition or nonspecific genetic deletion of CXCR2 appears to augment myelin repair in animal models of the human demyelinating disease multiple sclerosis (MS). To better understand the biology of CXCR2 signaling on oligodendroglia, we generated transgenic mice in which Cxcr2 is selectively ablated in oligodendroglia upon treatment with tamoxifen. Using a viral model of neuroinflammation and demyelination, we demonstrate that genetic silencing of CXCR2 on oligodendroglia did not affect clinical disease, neuroinflammation, or demyelination, yet there was increased remyelination. These findings support and extend previous findings suggesting that targeting CXCR2 may offer a therapeutic avenue for enhancing remyelination in patients with demyelinating diseases
Model/data comparisons of ozone in the upper stratosphere and mesosphere
We compare ground-based microwave observations of ozone in the upper stratosphere and mesosphere with daytime observations made from the SME (Solar Mesosphere Explorer) satellite, with nighttime data from the LIMS instrument, and with a diurnal photochemical model. The results suggest that the data are all in reasonable agreement and that the model-data discrepancy is much less than previously thought, particularly in the mesosphere. This appears to be due to the fact that the latest data are lower than earlier reports and the updated model predicts more ozone than older versions. The model and the data agree to within a factor of 1.5 at all altitudes and typically are within 20 percent
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