Denitrification drives total nitrate uptake in small Puerto Rican streams

An intensive study that was part of the Lotic Intersite Nitrogen eXperiment II (LINX II) project was conducted to determine nitrogen transformations in nine low-order streams with contrasting land use. Short term (24-hour) additions of K15NO3 and NaBr were performed on a gradient of anthropogenically impacted streams in Puerto Rico. Nitrate uptake was determined from longitudinal decline in 15NO3 and denitrification rates were determined from the longitudinal pattern of 15N 2 and 15N2O. Several physical, chemical, and biological variables were also measured to determine controlling factors. I performed these experiments to investigate: (1) the mechanisms for NO3 uptake and denitrification in tropical streams, (2) how tropical streams differ from temperate streams in their rates and controls on NO3 uptake and denitrification and (3) the functional responses of these streams as NO3 concentrations increase due to anthropogenic impacts. Background nitrate concentrations ranged from 105 to 997 mug N L -1 and stream nitrate uptake length varied from 315 to 8480 m (median of 1200 m). Uptake length was mainly predicted by specific discharge (L s -1 m-1) and ecosystem respiration rate (multiple regression analysis; r2 = 0.71, p \u3c 0.05). The other nitrate uptake parameters (Vf, cm/s and U, mug N m-2 s -1) were primarily predicted by gross primary production and respiration, indicating strong biological control on nitrate uptake. Denitrification rates ranged from 0.01 to 2.20 mug N m-2 s-1 (median = 0.25) and the strongest predictors were respiration and fine benthic organic matter (r2 = 0.89, p \u3c 0.05). Denitrification accounted for 1 to 97% of nitrate uptake with 5 of 9 streams having 35% or more of nitrate uptake via denitrification showing that denitrification is a substantial sink for nitrate in tropical streams. In comparison to rates in other regions, nitrate uptake was low and denitrification was high. Whole stream nitrate uptake more closely followed Michealis-Menten kinetics than in other regions, indicating that high N streams are approaching nitrate saturation. The efficiency with which these streams assimilate and remove nitrate (through denitrification) generally declines with increasing nitrate concentrations and loading

Aquatic biosurvey of the Lovell River on UNH land

We assessed the physical, chemical and biological conditions at two sites along the Lovell River on University of New Hampshire (UNH) -owned conservation land. The discharge was 4.4 m3 s-1 at Site 1 and 5.7 m3 s -1 downstream at Site 2. Canopy coverage ranged from 8-25%. Canopy was dominated by Eastern Hemlock (79-84%). Much of the stream was strewn with large boulders and the substrate consisted of rocks of highly variable sizes ( 3-549 cm dia.). Specific conductivity (22.1-23.3 µS), pH (6.4) and temperature (7.9-8.3 °C) varied little between sites. Macro-invertebrate bio-indices indicated either excellent water quality with no apparent organic pollution (3.0/10) or good water quality with possible slight organic pollution (4.4/10)

Leaf-litter leachate is distinct in optical properties and bioavailability to stream heterotrophs

Dissolved organic C (DOC) leached from leaf litter contributes to the C pool of stream ecosystems and affects C cycling in streams. We studied how differences in leaf-litter chemistry affect the optical properties and decomposition of DOC. We used 2 species of cottonwoods (Populus) and their naturally occurring hybrids that differ in leaf-litter phytochemistry and decomposition rate. We measured DOC and nutrient concentration in leaf leachates and determined the effect of DOC quality on heterotrophic respiration in 24-h incubations with stream sediments. Differences in DOC composition and quality were characterized with fluorescence spectroscopy. Rapidly decomposing leaves with lower tannin and lignin concentrations leached ~40 to 50% more DOC and total dissolved N than did slowly decomposing leaves. Rates of heterotrophic respiration were 25 to 50% higher on leachate from rapidly decomposing leaf types. Rates of heterotrophic respiration were related to metrics of aromaticity. Specifically, rates of respiration were correlated negatively with the Fluorescence Index and positively with Specific Ultraviolet Absorbance (SUVA254) and T280 tryptophan-like fluorescence peak. These results reveal that leaf-litter DOC is distinctly different from ambient streamwater DOC. The relationships between optical characteristics of leaf leachate and bioavailability are opposite those found in streamwater DOC. Differences in phytochemistry among leaf types can influence stream ecosystems with respect to DOC quantity, composition, and rates of stream respiration. These patterns suggest that the relationship between the chemical structure of DOC and its biogeochemistry is more complex than previously recognized. These unique properties of leaf-litter DOC will be important when assessing the effects of terrestrial C on aquatic ecosystems, especially during leaf fall

Salinization of urbanizing New Hampshire streams and groundwater: effects of road salt and hydrologic variability

Since the 1940s, use of road salt as a deicing agent has increased substantially in regions of the US with cold winters. Despite its ubiquitous application and known negative consequences for aquatic and human health, little research has documented the effects of road salt on the water quality of either streams or groundwater in regions, such as New Hampshire (NH), with harsh northern climates. We measured stream Na(+) and Cl(-) concentrations in 44 basins spanning a gradient of urbanization in southeastern and central NH. Among all sampled basins, stream Na(+) and Cl(-) concentrations were highly correlated with basin % road pavement (r(2) = 0.75 for Na(+), and 0.78 for Cl(-)). In southeastern NH, concentrations also were correlated strongly with % impervious surface (r(2) = 0.86 for Na(+), and 0.92 for Cl(-)). Groundwater salt concentrations in 143 private wells were significantly correlated with % impervious surface within a 500-m radius of each well, but the proportion of explained variance was small (r(2) = 0.07 for Na(+), and 0.10 for Cl(-)). Concentrations of salt in streams and groundwater were surprisingly high. Mean concentrations of Na(+) ranged from \u3c1 to 298 mg/L and of Cl(-) ranged from \u3c1 to 573 mg/L. Mean Cl(-) concentration in I small stream exceeded the US Environmental Protection Agency (EPA) chronic toxicity standard of 230 mg/L, and 9% of groundwater samples exceeded the secondary EPA maximum contamination levels for drinking water (250 mg/L of either Na(+) or Cl(-)). In our long-term study basin, the Lamprey River, specific conductance increased over the period from 1978 to 2008, a result that indicated a corresponding increase in Na(+) and Cl(-) concentrations. Both Na(+) and Cl(-) concentrations in the Lamprey River were negatively correlated with flow, but the slope of the relationship decreased after a significant flood in 2006. Our data suggest that road-salting practices are contributing to the salinization of stream water and groundwater in NH, and that hydrologic variability, which is predicted to increase with climate change, could strongly affect the degree of salinization observed in surface waters

Exploration and Discovery of Hydrocarbon Seeps, Coral Ecosystems, and Shipwrecks in the Deep Gulf of Mexico

Between March 20 and April 6, 2012, the NOAA Ship Okeanos Explorer served as a platform for ship-board and shore-side scientists to explore the deep Gulf of Mexico, targeting the northern West Florida Escarpment, DeSoto Canyon, the vicinity (within 11km) of the Deepwater Horizon (DWH) well, and deepwater shipwrecks. We systematically explored and discovered natural hydrocarbon seeps, diverse coral ecosystems, wooden and iron-hulled shipwrecks more than 100 years old colonized by coral communities, and sperm whale habitat between 600 and 1200m. A total of sixteen dives took advantage of new and recent maps to explore and groundtruth both hard and soft-bottom habitats, from cretaceous carbonates to mounds of coral rubble. The final ROV dive successfully groundtruthed expected methane-release areas imaged by the ship’s mapping systems up to 1150m above the seafloor. The source of the mapping imagery was a stream of bubbles issuing from beneath thriving seep mussel communities. We visited five sites in the Mississippi Canyon (MC) area (lease blocks MC294, MC297, MC388, MC255, and MC036; the DWH incident took place in MC252). These sites were 11.3 km SW, 6.8 km SW, 7.6 km SW, 25.7 km E, and 27.4 km to the NE of the DWH, respectively. We used high-definition imaging systems on the Little Hercules ROV and Seirios camera platform to document more than 130 coral colonies and over 400 associated individual animals to continue to assessing the impact of the Deepwater Horizon oil spill. All of these efforts were conducted to provide fundamental knowledge of unknown and poorly known regions, ecosystems, and items of historical significance in the deep Gulf of Mexico

The Preventing Alzheimer\u27s with Cognitive Training (PACT) randomized clinical trial

BACKGROUND: To address the rising prevalence of Alzheimer\u27s disease and related dementias, effective interventions that can be widely disseminated are warranted. The Preventing Alzheimer\u27s with Cognitive Training study (PACT) investigates a commercially available computerized cognitive training program targeting improved Useful Field of View Training (UFOVT) performance. The primary goal is to test the effectiveness of UFOVT to reduce incidence of clinically defined mild cognitive impairment (MCI) or dementia with a secondary objective to examine if effects are moderated by plasma β-amyloid level or apolipoprotein E e4 (APOE e4) allele status. METHODS/DESIGN: This multisite study utilizes a randomized, controlled experimental design with blinded assessors and investigators. Individuals who are 65 years of age and older are recruited from the community. Eligible participants who demonstrate intact cognitive status (Montreal Cognitive Assessment score \u3e 25) are randomized and asked to complete 45 sessions of either a commercially available computerized-cognitive training program (UFOVT) or computerized games across 2.5 years. After three years, participants are screened for cognitive decline. For those demonstrating decline or who are part of a random subsample, a comprehensive neuropsychological assessment is completed. Those who perform below a pre-specified level are asked to complete a clinical evaluation, including an MRI, to ascertain clinical diagnosis of normal cognition, MCI, or dementia. Participants are asked to provide blood samples for analyses of Alzheimer\u27s disease related biomarkers. DISCUSSION: The PACT study addresses the rapidly increasing prevalence of dementia. Computerized cognitive training may provide a non-pharmaceutical option for reducing incidence of MCI or dementia to improve public health. REGISTRATION: The PACT study is registered at http://Clinicaltrials.govNCT03848312

Monoclonal Antibodies Specific for SARS-CoV-2 Spike Protein Suitable for Multiple Applications for Current Variants of Concern

The global coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spawned an ongoing demand for new research reagents and interventions. Herein we describe a panel of monoclonal antibodies raised against SARS-CoV-2. One antibody showed excellent utility for immunohistochemistry, clearly staining infected cells in formalin-fixed and paraffin embedded lungs and brains of mice infected with the original and the omicron variants of SARS-CoV-2. We demonstrate the reactivity to multiple variants of concern using ELISAs and describe the use of the antibodies in indirect immunofluorescence assays, Western blots, and rapid antigen tests. Finally, we illustrate the ability of two antibodies to reduce significantly viral tissue titers in K18-hACE2 transgenic mice infected with the original and an omicron isolate of SARS-CoV-2

SVEP1 as a Genetic Modifier of TEK-Related Primary Congenital Glaucoma

PURPOSE. Affecting children by age 3, primary congenital glaucoma (PCG) can cause debilitating vision loss by the developmental impairment of aqueous drainage resulting in high intraocular pressure (IOP), globe enlargement, and optic neuropathy. TEK haploinsufficiency accounts for 5% of PCG in diverse populations, with low penetrance explained by variable dysgenesis of Schlemm’s canal (SC) in mice. We report eight families with TEK-related PCG, and provide evidence for SVEP1 as a disease modifier in family 8 with a higher penetrance and severity. METHODS. Exome sequencing identified coding/splice site variants with an allele frequency less than 0.0001 (gnomAD). TEK variant effects were assayed in constructtransfected HEK293 cells via detection of autophosphorylated (active) TEK protein. An enucleated eye from an affected member of family 8 was examined via histology. SVEP1 expression in developing outflow tissues was detected by immunofluorescent staining of 7-day mouse anterior segments. SVEP1 stimulation of TEK expression in human umbilical vascular endothelial cells (HUVECs) was measured by TaqMan quantitative PCR. RESULTS. Heterozygous TEK loss-of-function alleles were identified in eight PCG families, with parent–child disease transmission observed in two pedigrees. Family 8 exhibited greater disease penetrance and severity, histology revealed absence of SC in one eye, and SVEP1:p.R997C was identified in four of the five affected individuals. During SC development, SVEP1 is secreted by surrounding tissues. SVEP1:p.R997C abrogates stimulation of TEK expression by HUVECs. CONCLUSIONS. We provide further evidence for PCG caused by TEK haploinsufficiency, affirm autosomal dominant inheritance in two pedigrees, and propose SVEP1 as a modifier of TEK expression during SC development, affecting disease penetrance and severity.Supported by the National Institutes of Health [R01EY014685 to T.Y., R01HL124120, T32DK108738, R01EY025799, and P30DK114857 to S.Q.]; the Research to Prevent Blindness Inc. [Lew R. Wasserman Award to T.Y.]; a University of Wisconsin Centennial Scholars Award [to T.Y.]; the Flinders Foundation and the National Health and Medical Research Council of Australia [APP1116360, APP1107098, and fellowship APP1154824 to J.C.]; the Foundation for Science and Technology, Human Potential Operational Program/European Social Fund [fellowship SFRH/BD/90445/2012 to S.C.]; the Agency for Science Technology and Research, under the Industry Alignment Fund - Pre-Positioning Programme, as part of the Innovations in Food & Chemical Safety Programme [H18/01/a0/b14 to V.L.]; the Ophthalmic Research Center of Shahid Beheshti University of Medical Sciences and the Iran National Science Foundation [940012 to E.E.]; a Core Grant for Vision Research from the National Eye Institute/National Institutes of Health to the University of Wisconsin-Madison [P30EY016665]; and an Unrestricted Grant from Research to Prevent Blindness, Inc. to the UW-Madison Department of Ophthalmology and Visual Sciences. The authors are grateful to the Vanderbilt clinical site of the Undiagnosed Diseases Network for contribution of one individual for this manuscript: John A Phillips III, John H. Newman, Joy Cogan, and Rizwan Hamid; supported in part by the National Institutes of Health Common Fund [UO1HG007674]