Impacts of invasive species are often context specific due to varying ecological interactions. Physical structure of environments hosting invaders is also potentially important but has received limited attention. An invasive macroalga, Agarophyton vermiculophyllum, has spread across the northern hemisphere with mixed positive, neutral and negative effects on resident species.
View Article and Find Full Text PDFExotic species may increase or decrease native biodiversity. However, effects of exotic species are often mixed; and indirect pathways and compensatory changes can mask effects. Context-specific assessments of the indirect impacts of exotic species are also needed across multiple spatial scales.
View Article and Find Full Text PDFA hallmark pathology of Alzheimer's disease (AD) is the formation of amyloid β (Aβ) deposits that exhibit diverse localization and morphologies, ranging from diffuse to cored-neuritic deposits in brain parenchyma, with cerebral vascular deposition in leptomeningeal and parenchymal compartments. Most AD brains exhibit the full spectrum of pathologic Aβ morphologies. In the course of studies to model AD amyloidosis, we have generated multiple transgenic mouse models that vary in the nature of the transgene constructs that are expressed; including the species origin of Aβ peptides, the levels and length of Aβ that is deposited, and whether mutant presenilin 1 (PS1) is co-expressed.
View Article and Find Full Text PDFAtlas Oral Maxillofac Surg Clin North Am
September 2019
Larvae of Prionus californicus Motschulsky feed on the roots of many woody perennial plants and are economically important pests of hop Humulus lupulus L. (Urticales: Cannabaceae) and sweet cherry Prunus avium (L.) (Magnoliopsida: Rosaceae) in the United States Pacific Northwest and Intermountain West.
View Article and Find Full Text PDFTo date, the infrasound community has avoided deployments in noisy urban sites because interests have been in monitoring distant sources with low noise sites. As monitoring interests expand to include low-energy urban sources only detectable close to the source, case studies are needed to demonstrate the challenges and benefits of urban infrasound monitoring. This case study highlights one approach to overcoming urban challenges and identifies a signal's source in a complex acoustic field.
View Article and Find Full Text PDFPhilos Trans R Soc Lond B Biol Sci
December 2018
Widespread changes in water temperatures, salinity, alkalinity and pH have been documented in inland waters in North America, which influence ion exchange, weathering rates, chemical solubility and contaminant toxicity. Increasing major ion concentrations from pollution, human-accelerated weathering and saltwater intrusion contribute to multiple ecological stressors such as changing ionic strength and pH and mobilization of chemical mixtures resulting in the freshwater salinization syndrome (FSS). Here, we explore novel combinations of elements, which are transported together as chemical mixtures containing salts, nutrients and metals as a consequence of FSS.
View Article and Find Full Text PDFOrganic carbon accumulation in the sediments of inland aquatic and coastal ecosystems is an important process in the global carbon budget that is subject to intense human modification. To date, research has focused on quantifying accumulation rates in individual or groups of aquatic ecosystems to quantify the aquatic carbon sinks. However, there hasn't been a synthesis of rates across aquatic ecosystem to address the variability in rates within and among ecosystems types.
View Article and Find Full Text PDFThe deposition of pathologic misfolded proteins in neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, frontotemporal dementia and amyotrophic lateral sclerosis is hypothesized to burden protein homeostatic (proteostatic) machinery, potentially leading to insufficient capacity to maintain the proteome. This hypothesis has been supported by previous work in our laboratory, as evidenced by the perturbation of cytosolic protein solubility in response to amyloid plaques in a mouse model of Alzheimer's amyloidosis. In the current study, we demonstrate changes in proteome solubility are a common pathology to mouse models of neurodegenerative disease.
View Article and Find Full Text PDFBackground: Prior studies in C. elegans demonstrated that the expression of aggregation-prone polyglutamine proteins in muscle wall cells compromised the folding of co-expressed temperature-sensitive proteins, prompting interest in whether the accumulation of a misfolded protein in pathologic features of human neurodegenerative disease burdens cellular proteostatic machinery in a manner that impairs the folding of other cellular proteins.
Methods: Mice expressing high levels of mutant forms of tau and α-synuclein (αSyn), which develop inclusion pathologies of the mutant protein in brain and spinal cord, were crossed to mice expressing low levels of mutant superoxide dismutase 1 fused to yellow fluorescent protein (G85R-SOD1:YFP) for aging and neuropathological evaluation.
Salt pollution and human-accelerated weathering are shifting the chemical composition of major ions in fresh water and increasing salinization and alkalinization across North America. We propose a concept, the freshwater salinization syndrome, which links salinization and alkalinization processes. This syndrome manifests as concurrent trends in specific conductance, pH, alkalinity, and base cations.
View Article and Find Full Text PDFUnderstanding the factors that affect water quality and the ecological services provided by freshwater ecosystems is an urgent global environmental issue. Predicting how water quality will respond to global changes not only requires water quality data, but also information about the ecological context of individual water bodies across broad spatial extents. Because lake water quality is usually sampled in limited geographic regions, often for limited time periods, assessing the environmental controls of water quality requires compilation of many data sets across broad regions and across time into an integrated database.
View Article and Find Full Text PDFWidespread evidence that organic matter exported from terrestrial into aquatic ecosystems supports recipient food webs remains controversial. A pressing question is not only whether high terrestrial support is possible but also what the general conditions are under which it arises. We assemble the largest data set, to date, of the isotopic composition (δH, δC, and δN) of lake zooplankton and the resources at the base of their associated food webs.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2017
Directional change in environmental drivers sometimes triggers regime shifts in ecosystems. Theory and experiments suggest that regime shifts can be detected in advance, and perhaps averted, by monitoring resilience indicators such as variance and autocorrelation of key ecosystem variables. However, it is uncertain whether management action prompted by a change in resilience indicators can prevent an impending regime shift.
View Article and Find Full Text PDFThe capacity of the cell to produce, fold and degrade proteins relies on components of the proteostasis network. Multiple types of insults can impose a burden on this network, causing protein misfolding. Using thermal stress, a classic example of acute proteostatic stress, we demonstrate that ∼5-10% of the soluble cytosolic and nuclear proteome in human HEK293 cells is vulnerable to misfolding when proteostatic function is overwhelmed.
View Article and Find Full Text PDFThe interaction between human activities and watershed geology is accelerating long-term changes in the carbon cycle of rivers. We evaluated changes in bicarbonate alkalinity, a product of chemical weathering, and tested for long-term trends at 97 sites in the eastern United States draining over 260,000 km(2). We observed statistically significant increasing trends in alkalinity at 62 of the 97 sites, while remaining sites exhibited no significant decreasing trends.
View Article and Find Full Text PDFThe supplementary eye fields (SEF) are thought to enable higher-level aspects of oculomotor control. The goal of the present experiment was to learn more about the SEF's role in orienting, specifically by examining neck muscle recruitment evoked by stimulation of the SEF. Neck muscle activity was recorded from multiple muscles in two monkeys during SEF stimulation (100 μA, 150-300 ms, 300 Hz, with the head restrained or unrestrained) delivered 200 ms into a gap period, before a visually guided saccade initiated from a central position (doing so avoids confounds between initial position and prestimulation neck muscle activity).
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