2,717 research outputs found

    A preliminary report on the contact-independent antagonism of Pseudogymnoascus destructans by Rhodococcus rhodochrous strain DAP96253.

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    BackgroundThe recently-identified causative agent of White-Nose Syndrome (WNS), Pseudogymnoascus destructans, has been responsible for the mortality of an estimated 5.5 million North American bats since its emergence in 2006. A primary focus of the National Response Plan, established by multiple state, federal and tribal agencies in 2011, was the identification of biological control options for WNS. In an effort to identify potential biological control options for WNS, multiply induced cells of Rhodococcus rhodochrous strain DAP96253 was screened for anti-P. destructans activity.ResultsConidia and mycelial plugs of P. destructans were exposed to induced R. rhodochrous in a closed air-space at 15°C, 7°C and 4°C and were evaluated for contact-independent inhibition of conidia germination and mycelial extension with positive results. Additionally, in situ application methods for induced R. rhodochrous, such as fixed-cell catalyst and fermentation cell-paste in non-growth conditions, were screened with positive results. R. rhodochrous was assayed for ex vivo activity via exposure to bat tissue explants inoculated with P. destructans conidia. Induced R. rhodochrous completely inhibited growth from conidia at 15°C and had a strong fungistatic effect at 4°C. Induced R. rhodochrous inhibited P. destructans growth from conidia when cultured in a shared air-space with bat tissue explants inoculated with P. destructans conidia.ConclusionThe identification of inducible biological agents with contact-independent anti- P. destructans activity is a major milestone in the development of viable biological control options for in situ application and provides the first example of contact-independent antagonism of this devastating wildlife pathogen

    Cysteine 893 is a target of regulatory thiol modifications of GluA1 AMPA receptors

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    Recent studies indicate that glutamatergic signaling involves, and is regulated by, thiol modifying and redox-active compounds. In this study, we examined the role of a reactive cysteine residue, Cys-893, in the cytosolic C-terminal tail of GluA1 AMPA receptor as a potential regulatory target. Elimination of the thiol function by substitution of serine for Cys-893 led to increased steady-state expression level and strongly reduced interaction with SAP97, a major cytosolic interaction partner of GluA1 C-terminus. Moreover, we found that of the three cysteine residues in GluA1 C-terminal tail, Cys-893 is the predominant target for Snitrosylation induced by exogenous nitric oxide donors in cultured cells and lysates. Co-precipitation experiments provided evidence for native association of SAP97 with neuronal nitric oxide synthase (nNOS) and for the potential coupling of Ca2+- permeable GluA1 receptors with nNOS via SAP97. Our results show that Cys-893 can serve as a molecular target for regulatory thiol modifications of GluA1 receptors, including the effects of nitric oxide.Peer reviewe

    ADCP Observations of Currents and Suspended Sediment in the Macrotidal Gulf of Martaban, Myanmar

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    The Ayeyarwady and Thanlwin Rivers, which drain Myanmar, together form one of the largest point sources of freshwater and sediment to the global ocean. Combined, these rivers annually deliver an estimated 485 Mt of sediment to the northern Andaman Sea. This sediment contributes to a perennially muddy zone within the macro-tidal Gulf of Martaban, but little is known about the processes that dominate dispersal and trapping of sediment there, as very few water column observations are available. A research cruise in December 2017 provided a rare opportunity to obtain Acoustic Doppler Current Profiler (ADCP) data along transects from the Gulf of Martaban and adjacent continental shelf. Two transects were obtained from the outer portion of the Gulf of Martaban in water depths that ranged from about 20–35 m. These showed very fast currents, especially during flood tide conditions, exceeding 1.5 m/s. The backscatter record from the ADCP indicated asymmetries in distribution of suspended sediment during the ebb versus flood phase of the tide. During ebb tidal conditions, the backscatter record indicated that sediment was transported in either a surface advected layer, or fairly well-mixed throughout the water column. In contrast, during flood tidal conditions, sediment was confined to the bottom boundary layer, even though the velocities were faster during flood than the ebb conditions. The vertical structure of the currents during flood tide conditions indicated the presence of sediment–induced stratification because currents within the near-bed turbid layers were relatively slow, but speeds increased markedly above these layers. This albeit limited dataset provides an exciting glimpse into the dynamics of sediment transport within the muddy, macrotidal Gulf of Martaban, and implies the importance of tidal straining and bottom nepheloid layer formation there

    Child Care Provider Survival Analysis

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    The aggregate ability of child care providers to meet local demand for child care is linked to employment rates in many sectors of the economy. Amid growing concern regarding child care provider sustainability due to the COVID-19 pandemic, state and local governments have received large amounts of new funding to better support provider stability. In response to this new funding aimed at bolstering the child care market in Florida, this study was devised as an exploratory investigation into features of child care providers that lead to business longevity. In this study we used optimal survival trees, a machine learning technique designed to better understand which providers are expected to remain operational for longer periods of time, supporting stabilization of the child care market. This tree-based survival analysis detects and describes complex interactions between provider characteristics that lead to differences in expected business survival rates. Results show that small providers who are religiously affiliated, and all providers who are serving children in Florida's universal Prekindergarten program and/or children using child care subsidy, are likely to have the longest expected survival rates.Comment: 20 pages, 2 figure

    Space Launch System Booster Separation Supersonic Powered Testing with Surface and Off-Body Measurements

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    A wind tunnel test was run in the NASA Langley Unitary Plan Wind Tunnel simulating the separation of the two solid rocket boosters (SRB) from the core stage of the NASA Space Launch System (SLS). The test was run on a 0.9% scale model of the SLS Block 1B Cargo (27005) configuration and the SLS Block 1B Crew (28005) configuration at a Mach of 4.0. High pressure air was used to simulate plumes from the booster separation motors located at the nose and aft skirt of the two boosters. Force and moment data were taken on both SRBs and on the core stage. Schlieren still photos and video were recorded throughout testing. A set of points were acquired using Cross-correlation Doppler Global Velocimetry (CCDGV) readings to get 3 component velocity measurements between the core and the left-hand SRB. The CCDGV laser was utilized to record flow visualization in the same location, between the core and the left-hand SRB. Pressure Sensitive Paint data were taken on a separate set of runs. Computational Fluid Dynamics (CFD) runs were computed on a subset of the wind tunnel data points for comparison. A combination of the force/moment, CCDGV and Pressure Sensitive Paint (PSP) data (as well as schlieren images) at the CFD-specified test conditions will be used te the CFD simulations that will be used to build an SLS booster separation database flight conditions

    Molecules in external fields: a semiclassical analysis

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    We undertake a semiclassical analysis of the spectral properties (modulations of photoabsorption spectra, energy level statistics) of a simple Rydberg molecule in static fields within the framework of Closed-Orbit/Periodic-Orbit theories. We conclude that in addition to the usual classically allowed orbits one must consider classically forbidden diffractive paths. Further, the molecule brings in a new type of 'inelastic' diffractive trajectory, different from the usual 'elastic' diffractive orbits encountered in previous studies of atomic and analogous systems such as billiards with point-scatterers. The relative importance of inelastic versus elastic diffraction is quantified by merging the usual Closed Orbit theory framework with molecular quantum defect theory.Comment: 4 pages, 3 figure

    Acute Beetroot Juice Ingestion Increases Nitric Oxide Bioavailability Without Changing Oral Microbial Composition in Healthy Young Women

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    Dietary nitrate supplementation can elicit beneficial health and exercise performance effects. Oral microbiota are critical for the metabolism of exogenously consumed nitrate; however, limited data are available on the influence of dietary nitrate ingestion on bacterial taxa and in women. PURPOSE: To investigate if acute dietary nitrate ingestion alters the oral microbiota in young healthy women compared to a nitrate-depleted placebo. METHODS: In a randomized double-blinded crossover design, fifteen recreationally active women (mean ± SD: age 20 ± 1 years; body mass 63 ± 10 kg; height 1.68 ± 0.1 m) participated in two conditions to ingest nitrate-rich beetroot juice (BR; 12 mmol of nitrate) and nitrate-depleted beetroot juice (PL, negligible nitrate), 2.5 hours prior to a resting blood draw and buccal swab sample. Plasma [nitrate] and [nitrite] were analyzed using gas phase chemiluminescence. Buccal swab samples were used for DNA extraction and isolation. DNA was amplified using polymerase chain reaction targeting the V3 - V4 region of the 16S rRNA gene. Following index PCR, amplicons were pooled and sequenced using the iSeq Illumina NGS sequencer. Reads were clustered into amplicon sequence variants and analyzed for alpha and beta diversity and relative abundance. RESULTS: BR increased plasma [nitrate] (PL: 52 ± 14 µM vs. BR: 629 ± 132 µM, P \u3c 0.001) and plasma [nitrite] (PL: 276 ± 286 nM vs. BR: 703 ± 391 nM, P \u3c 0.001). One sample had insufficient DNA and thus, a subset of samples was analyzed for oral microbial composition (n = 14). Alpha (i.e., species richness or evenness) and beta diversity was not different between PL and BR (P \u3e 0.05). The relative abundance of the phylum and genus were not influenced by BR (P \u3e 0.05). CONCLUSION: Acute nitrate ingestion did not improve or worsen the composition of global or lower taxonomic levels of bacteria in young recreationally active women. These data indicate that acute nitrate ingestion is an intervention to rapidly increase nitric oxide bioavailability in young recreationally active women, which is an effect that did not require changes to the oral microbial community. Further research is required to understand the impact of dosing regimen and population on oral bacterial taxa and the efficacy of nitrate on nitrate-induced effects
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