Variable rates of hybridization among contact zones between a pair of topminnow species, and .

Pairs of species that exhibit broadly overlapping distributions, and multiple geographically isolated contact zones, provide opportunities to investigate the mechanisms of reproductive isolation. Such naturally replicated systems have demonstrated that hybridization rates can vary substantially among populations, raising important questions about the genetic basis of reproductive isolation. The topminnows, and , are reciprocally monophyletic, and co-occur in drainages throughout much of the central and southern United States.

Sex differences in brain tumor glutamine metabolism reveal sex-specific vulnerabilities to treatment.

Background: Brain cancer incidence and mortality rates are greater in males. Understanding the molecular mechanisms that underlie those sex differences could improve treatment strategies. Although sex differences in normal metabolism are well described, it is currently unknown whether they persist in cancerous tissue.

Molecular basis of secondary relaxation in stiff-chain glassy polymers.

Recent progress in establishing local order in polycarbonate-like glasses using rotational echo double resonance and centerband-only detection of exchange solid-state nuclear magnetic resonance (NMR) has stimulated a renewed attempt to connect molecular motion within glassy polymers and the mechanical properties of the glass. We have in fact established a correlation between molecular motion characterized by NMR and the mechanical secondary relaxation (tan δ) for nine polycarbonate-like glasses. All of the NMR and mechanical data are for T ≪ Tg.

Quantitative rotational-echo double resonance for Carbon-13 spin clusters.

By using only half of the total evolution time for dephasing pulses, C{N} rotational-echo double resonance (REDOR) for clusters of C spins (RDX) results in the same universal REDOR behavior as observed for isolated C-N pairs. RDX combines Hahn echoes with solid echoes to suppress interference from scalar J couplings. This is crucial for long evolution times.

Implementation of formal prescription guidelines reduces the economic cost of unused opioids after orthopedic surgery.

Prior literature has reported on the concerning emergence of opioid overprescribing, yet there remains a lack of knowledge in understanding the cost of waste of this over-prescription and underconsumption of opioids. As such, further investigating the cost of waste of opioids following orthopedic surgery is of interest to patients, providers, and payors. In one of the largest private orthopedic practices in the United States, opioid prescribing and consumption patterns were tracked prior to, and after the implementation of, formal prescription guidelines.

Prognostic Value of Urinary and Plasma C-Type Natriuretic Peptide in Acute Decompensated Heart Failure.

Objectives: This study sought to characterize urinary and plasma C-type natriuretic peptide (CNP) in acute decompensated heart failure (ADHF) to define their relationship with clinical variables and to determine whether urinary and plasma CNP together add prognostic value.

Background: CNP is a protective hormone that is synthesized in the kidney and endothelium and possesses antiremodeling properties. Urinary and plasma CNP levels are elevated in pathophysiological conditions; however, their regulation and prognostic value in heart failure (HF) is unclear.

Opioid-Prescribing Practices Between Total Knee and Hip Arthroplasty in an Outpatient Versus Inpatient Setting.

Despite trends showing increases in the utilization of outpatient (OP) ambulatory surgery centers (ASCs) and decreases in the utilization of inpatient (IP) facilities for total knee arthroplasty (TKA) and total hip arthroplasty (THA), little is known about opioid prescribing for these procedures between each setting. This study evaluated differences in opioid prescribing and consumption between OP ASC and IP settings for elective TKA and THA surgeries over a 1-year period. Data collection also included pain and satisfaction of pain control postsurgery.

Long-term blood pressure lowering and cGMP-activating actions of the novel ANP analog MANP.

Based on the cardiac hormone atrial natriuretic peptide (ANP) and its seminal role in blood pressure (BP) homeostasis, we investigated the chronic BP lowering actions of a novel ANP analog currently entering clinical trials for hypertension. Previous reports demonstrate that this analog MANP activates the guanylyl cyclase A receptor (GC-A) and results in more potent biological actions compared with ANP; thus, it may represent a new therapeutic drug for hypertension. A major goal of this study was to establish that chronic subcutaneous delivery of MANP is feasible and hypotensive together with cGMP effects.

Left ventricle assist device pulsatility index at the time of implantation is associated with follow-up pulmonary hemodynamics.

HeartMate II left ventricular assist device controllers provide data including pulsatility index, reflecting the relationship between pump function and hemodynamics. We propose that a higher pulsatility index at hospital discharge following implant may be associated with less vascular congestion and improved clinical outcomes. A retrospective analysis of 40 patients (age 59.

Synthesis of Submicron PEDOT Particles of High Electrical Conductivity via Continuous Aerosol Vapor Polymerization.

Current state-of-the-art synthetic strategies produce conducting polymers suffering from low processability and unstable chemical and/or physical properties stifling research and development. Here, we introduce a platform for synthesizing scalable submicron-sized particles of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT). The synthesis is based on a hybrid approach utilizing an aerosol of aqueous oxidant droplets and monomer vapor to engineer a scalable synthetic scheme.

Differential Regulation of ANP and BNP in Acute Decompensated Heart Failure: Deficiency of ANP.

Objectives: This study investigated the differential regulation of circulating atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) in patients with acute decompensated heart failure (ADHF) and tested the hypothesis that a relative deficiency of ANP exists in a subgroup of patients with ADHF.

Background: The endocrine heart releases the cardiac hormones ANP and BNP, which play a key role in cardiovascular (CV), renal, and metabolic homeostasis. In heart failure (HF), both plasma ANP and BNP are increased as a compensatory homeostatic response to myocardial overload.

Humidity-swing mechanism for CO capture from ambient air.

A humidity-swing polymeric sorbent captures CO2 from ambient air at room temperature simply by changing the humidity level. To date there has been no direct experimental evidence to characterize the chemical mechanism for this process. In this report we describe the use of solid-state NMR to study the humidity-swing CO2 absorption/desorption cycle directly.

REDOR NMR Reveals Multiple Conformers for a Protein Kinase C Ligand in a Membrane Environment.

Bryostatin 1 (henceforth bryostatin) is in clinical trials for the treatment of Alzheimer's disease and for HIV/AIDS eradication. It is also a preclinical lead for cancer immunotherapy and other therapeutic indications. Yet nothing is known about the conformation of bryostatin bound to its protein kinase C (PKC) target in a membrane microenvironment.

The effect of diuresis on extravascular lung water and pulmonary function in acute decompensated heart failure.

Aims: The effect of extravascular lung water (EVLW) and relationship to functional status as a result of acute decompensated heart failure (ADHF) are not well understood. We sought to quantify changes in clinical variables, EVLW, airway anatomy, spirometry, and diffusing capacity for carbon monoxide before and after treatment for ADHF.

Methods And Results: Fifteen patients were recruited within 24 h of hospital admission.

Surface proteins and the formation of biofilms by Staphylococcus aureus.

Staphylococcus aureus biofilms pose a serious clinical threat as reservoirs for persistent infections. Despite this clinical significance, the composition and mechanism of formation of S. aureus biofilms are unknown.

Whole-Cell Detection of C-P Bonds in Bacteria.

Naturally produced molecules possessing a C-P bond, such as phosphonates and phosphinates, remain vastly underexplored. Although success stories like fosfomycin have reinvigorated small molecule phosphonate discovery efforts, bioinformatic analyses predict an enormous unexplored biological reservoir of C-P bond-containing molecules, including those attached to complex macromolecules. However, high polarity, a lack of chromophores, and complex macromolecular association impede phosphonate discovery and characterization.

Mechanistic Basis for ATP-Dependent Inhibition of Glutamine Synthetase by Tabtoxinine-β-lactam.

Tabtoxinine-β-lactam (TβL), also known as wildfire toxin, is a time- and ATP-dependent inhibitor of glutamine synthetase produced by plant pathogenic strains of Pseudomonas syringae. Here we demonstrate that recombinant glutamine synthetase from Escherichia coli phosphorylates the C3-hydroxyl group of the TβL 3-(S)-hydroxy-β-lactam (3-HβL) warhead. Phosphorylation of TβL generates a stable, noncovalent enzyme-ADP-inhibitor complex that resembles the glutamine synthetase tetrahedral transition state.

Characterization of the tertiary structure of the peptidoglycan of Enterococcus faecalis.

Solid-state NMR spectra of whole cells and isolated cell walls of Enterococcus faecalis grown in media containing combinations of C and N specific labels in d- and l-alanine and l-lysine (in the presence of an alanine racemase inhibitor alaphosphin) have been used to determine the composition and architecture of the cell-wall peptidoglycan. The compositional variables include the concentrations of (i) peptidoglycan stems without bridges, (ii) d-alanylated wall teichoic acid, (iii) cross-links, and (iv) uncross-linked tripeptide and tetra/pentapeptide stems. Connectivities of l-alanyl carbonyl‑carbon bridge labels to d-[3-C]alanyl and l-[ε-N]lysyl stem labels prove that the peptidoglycan of E.

Desleucyl-Oritavancin with a Damaged d-Ala-d-Ala Binding Site Inhibits the Transpeptidation Step of Cell-Wall Biosynthesis in Whole Cells of Staphylococcus aureus.

We have used solid-state nuclear magnetic resonance to characterize the exact nature of the dual mode of action of oritavancin in preventing cell-wall assembly in Staphylococcus aureus. Measurements performed on whole cells labeled selectively in vivo have established that des-N-methylleucyl-N-4-(4-fluorophenyl)benzyl-chloroeremomycin, an Edman degradation product of [F]oritavancin, which has a damaged d-Ala-d-Ala binding aglycon, is a potent inhibitor of the transpeptidase activity of cell-wall biosynthesis. The desleucyl drug binds to partially cross-linked peptidoglycan by a cleft formed between the drug aglycon and its biphenyl hydrophobic side chain.

Dual Mode of Action for Plusbacin A in Staphylococcus aureus.

We have used C{F}, N{F}, and N{P} rotational-echo double resonance NMR to determine the location and conformation of F and N double-labeled plusbacin A and of double-labeled deslipo-plusbacin A, each bound to the cell walls of whole cells of Staphyloccocus aureus grown in media containing [1-C]glycine. The P is primarily in wall teichoic acid. Approximately 25% of plusbacin headgroups (the cyclic depsipeptide backbone) are in a closed conformation (N-F separation of 6 Å), while 75% are in a more open conformation (N-F separation of 12 Å).

Lactate metabolism is associated with mammalian mitochondria.

It is well established that lactate secreted by fermenting cells can be oxidized or used as a gluconeogenic substrate by other cells and tissues. It is generally assumed, however, that within the fermenting cell itself, lactate is produced to replenish NAD and then is secreted. Here we explore the possibility that cytosolic lactate is metabolized by the mitochondria of fermenting mammalian cells.

Hybridization and introgression in two ecologically dissimilar Fundulus hybrid zones.

Hybridization and introgression appear more common in rapidly evolving groups, suggesting an important role in the evolutionary process. Detailed studies of how extrinsic or intrinsic forces regulate hybridization and introgression have the potential for broadening our understanding of mechanisms generating diversity. Species in the Fundulus notatus species complex have broad overlapping ranges and occur in replicated hybrid zones along predictable stream gradients.

Exogenous Fatty Acids Are the Preferred Source of Membrane Lipids in Proliferating Fibroblasts.

Cellular proliferation requires the formation of new membranes. It is often assumed that the lipids needed for these membranes are synthesized mostly de novo. Here, we show that proliferating fibroblasts prefer to take up palmitate from the extracellular environment over synthesizing it de novo.

Fish faunal provinces of the conterminous United States of America reflect historical geography and familial composition.

Although the conterminous USA has a long history of ichthyological exploration, the description of biogeographical provinces has been ad hoc. In this study we quantitatively determined fish faunal provinces and interpreted them in the context of the geological history of North America. We also evaluated influences of major river basin occupancy and contemporary environmental factors on provincial patterns.

Derivation of the freshwater fish fauna of Central America revisited: Myers's hypothesis in the twenty-first century.

Although attempts to understand Central American freshwater fish provincialism date to the 1960s, early efforts lacked the wealth of distributional data now available. Biogeographic work on Central American freshwater fishes has been largely descriptive and regional, and lacked a broader synthesis. Here we use parsimony analysis of endemicity (PAE) to elucidate faunistic relationships between major drainages and to delineate areas of endemism.