Bacterial Bio-indicators of Marcellus Shale Activities in Pennsylvania: A Molecular Ecology Survey

The practice of hydraulic fracking has increased over the years especially in Pennsylvania where most of the subterraneous gas-rich Marcellus Shale formations are located. Our previous work showed that headwater streams in proximity to hydraulic fracking operations have significantly different bacterial assemblages as compared to un-impacted streams in central PA. Aquatic bacterial communities are of great importance because they are often the ‘first-responders’ to environmental perturbations. We are interested in which bacteria become enriched, as this might serve as robust biomarkers of fracking, and can potentially biodegrade constituents of fracking fluids. In this study, we plan to expand upon our previous work to identify additional sentinel bacterial taxa in other areas in PA (Northeast and Southwest) heavily impacted by fracking. Water and sediment samples have been collected from Northern Pennsylvania (n=31) and Southwestern (n=11) regions upstream and downstream of fracking activities. Bacterial community profiles of these samples were generated via high-throughput sequencing of the 16S rRNA, a robust phylogenetic marker for bacterial identification. The data generated provide a snapshot of all bacteria taxa present and their relative abundance. Thus, differences in bacterial community structure between impacted and un-impacted environments can help glean which bacterial taxa are responding to environmental perturbations associated with fracking. This research can help us generate a list of potential bioindicators of nascent fracking activities and can be used to help track impacts and bioremediation potential within environmental scenarios

Clostridioides difficile infection is associated with differences in transcriptionally active microbial communities

Clostridioides difficile infection (CDI) is responsible for around 300,000 hospitalizations yearly in the United States, with the associated monetary cost being billions of dollars. Gut microbiome dysbiosis is known to be important to CDI. To the best of our knowledge, metatranscriptomics (MT) has only been used to characterize gut microbiome composition and function in one prior study involving CDI patients. Therefore, we utilized MT to investigate differences in active community diversity and composition between CDI+ (n = 20) and CDI− (n = 19) samples with respect to microbial taxa and expressed genes. No significant (Kruskal-Wallis, p > 0.05) differences were detected for richness or evenness based on CDI status. However, clustering based on CDI status was significant for both active microbial taxa and expressed genes datasets (PERMANOVA, p ≤ 0.05). Furthermore, differential feature analysis revealed greater expression of the opportunistic pathogens Enterocloster bolteae and Ruminococcus gnavus in CDI+ compared to CDI− samples. When only fungal sequences were considered, the family Saccharomycetaceae expressed more genes in CDI−, while 31 other fungal taxa were identified as significantly (Kruskal-Wallis p ≤ 0.05, log(LDA) ≥ 2) associated with CDI+. We also detected a variety of genes and pathways that differed significantly (Kruskal-Wallis p ≤ 0.05, log(LDA) ≥ 2) based on CDI status. Notably, differential genes associated with biofilm formation were expressed by C. difficile. This provides evidence of another possible contributor to C. difficile’s resistance to antibiotics and frequent recurrence in vivo. Furthermore, the greater number of CDI+ associated fungal taxa constitute additional evidence that the mycobiome is important to CDI pathogenesis. Future work will focus on establishing if C. difficile is actively producing biofilms during infection and if any specific fungal taxa are particularly influential in CDI

Dark Matter Signals from Cascade Annihilations

A leading interpretation of the electron/positron excesses seen by PAMELA and ATIC is dark matter annihilation in the galactic halo. Depending on the annihilation channel, the electron/positron signal could be accompanied by a galactic gamma ray or neutrino flux, and the non-detection of such fluxes constrains the couplings and halo properties of dark matter. In this paper, we study the interplay of electron data with gamma ray and neutrino constraints in the context of cascade annihilation models, where dark matter annihilates into light degrees of freedom which in turn decay into leptons in one or more steps. Electron and muon cascades give a reasonable fit to the PAMELA and ATIC data. Compared to direct annihilation, cascade annihilations can soften gamma ray constraints from final state radiation by an order of magnitude. However, if dark matter annihilates primarily into muons, the neutrino constraints are robust regardless of the number of cascade decay steps. We also examine the electron data and gamma ray/neutrino constraints on the recently proposed "axion portal" scenario.Comment: 36 pages, 11 figures, 7 tables; references adde

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Synthesis, optical resolution, and stereochemical properties of a rationally designed chiral C–N palladacycle

A novel racemic tertiary amine, 1-(2,5-diisopropylphenyl)-N,N-dimethylethanamine, was synthesized from 2,5-diisopropylbenzaldehyde via a multistep approach in high overall yield. The ortho palladation of this ligand was found to be sensitive to the reaction conditions and the palladating reagents employed. The metal complexation process could thus generate a cyclopalladated complex in high yield, lead to an unexpected N-demethylated amine palladium(II) complex, or both. Both products have been isolated and characterized crystallographically in the solid state and spectroscopically in solution. The racemic cyclopalladated complex could be efficiently resolved via the formation of (S)-prolinato derivatives. The absolute stereochemistries of the resolved diastereomeric complexes were determined by single-crystal X-ray crystallography in the solid state and by 1H–1H rotating frame Overhauser effect (ROESY) NMR spectroscopy in solution. An evaluation of the sterically hindered resolved cyclopalladated units as chiral auxiliaries was conducted in the endo-cycloaddition reaction between 3,4-dimethyl-1-phenylphosphole (DMPP) and ethyl vinyl ketone. The two expected phosphanorbornene adducts were generated with moderate stereoselectivity.Accepted versio

Comparative study of the effects of biocides and metal oxide nanoparticles on microbial community structure in a stream impacted by hydraulic fracturing

Our study goal was to investigate the impact of biocides and nanoparticles (NPs) on the microbial diversity in a hydraulic fracturing impacted stream. Biocides and NPs are known for their antimicrobial properties and controlling microbial growth. Previous work has shown that biocides can alter the microbial community composition of stream water and may select for biocide-resistant bacteria. Additional studies have shown that nanoparticles can also alter microbial community composition. However, previous work has often focused on the response to a single compound. Here we provide a more thorough analysis of the microbial community response to three different biocides and three different nanoparticles. A microcosm-based study was undertaken that exposed stream microbial communities to either biocides or NPs. Our results showed a decrease in bacterial abundance with different types of nanoparticles, but an increase in microbial abundance in biocide-amended treatments. The microbial community composition (MCC) was distinct from the controls in all biocide and NP treatments, which resulted in differentially enriched taxa in the treatments compared to the controls. Our results indicate that NPs slightly altered the MCC compared to the biocide-treated microcosms. After 14 days, the MCC in the nanoparticle-treated conditions was similar to the MCC in the control. Conversely, the MCC in the biocide-treated microcosms was distinct from the controls at day 14 and distinct from all conditions at day 0. This finding may point to the use of NPs as an alternative to biocides in some settings