Amphiphilic Indole Derivatives as Antimycobacterial Agents: Structure-Activity Relationships and Membrane Targeting Properties.

Antibacterials that disrupt cell membrane function have the potential to eradicate "persister" organisms and delay the emergence of resistance. Here we report the antimycobacterial activities of 4-fluoro and 6-methoxyindoles bearing a cationic amphiphilic motif represented by a lipophilic n-octyl side chain at position 1 and a positively charged azepanyl or 1,4-dioxa-8-azaspiro[4.5]decane moiety at position 3.

In Vivo-Selected Pyrazinoic Acid-Resistant Mycobacterium tuberculosis Strains Harbor Missense Mutations in the Aspartate Decarboxylase PanD and the Unfoldase ClpC1.

Through mutant selection on agar containing pyrazinoic acid (POA), the bioactive form of the prodrug pyrazinamide (PZA), we recently showed that missense mutations in the aspartate decarboxylase PanD and the unfoldase ClpC1, and loss-of-function mutation of polyketide synthases Mas and PpsA-E involved in phthiocerol dimycocerosate synthesis, cause resistance to POA and PZA in Mycobacterium tuberculosis. Here we first asked whether these in vitro-selected POA/PZA-resistant mutants are attenuated in vivo, to potentially explain the lack of evidence of these mutations among PZA-resistant clinical isolates. Infection of mice with panD, clpC1, and mas/ppsA-E mutants showed that whereas growth of clpC1 and mas/ppsA-E mutants was attenuated, the panD mutant grew as well as the wild-type.

Systematic in vitro assessment of responses of roGFP2-based probes to physiologically relevant oxidant species.

The genetically encoded probes roGFP2-Orp1 and Grx1-roGFP2 have been designed to be selectively oxidized by hydrogen peroxide (HO) and glutathione disulfide (GSSG), respectively. Both probes have demonstrated such selectivity in a broad variety of systems and conditions. In this study, we systematically compared the in vitro response of roGFP2, roGFP2-Orp1 and Grx1-roGFP2 to increasing amounts of various oxidant species that may also occur in biological settings.

Comparison of human gastrocnemius forces predicted by Hill-type muscle models and estimated from ultrasound images.

Hill-type models are ubiquitous in the field of biomechanics, providing estimates of a muscle's force as a function of its activation state and its assumed force-length and force-velocity properties. However, despite their routine use, the accuracy with which Hill-type models predict the forces generated by muscles during submaximal, dynamic tasks remains largely unknown. This study compared human gastrocnemius forces predicted by Hill-type models with the forces estimated from ultrasound-based measures of tendon length changes and stiffness during cycling, over a range of loads and cadences.

Towards Selective Mycobacterial ClpP1P2 Inhibitors with Reduced Activity against the Human Proteasome.

is responsible for the greatest number of deaths worldwide due to a bacterial agent. We recently identified bortezomib (Velcade; compound 1) as a promising antituberculosis (anti-TB) compound. We showed that compound 1 inhibits the mycobacterial caseinolytic proteases P1 and P2 (ClpP1P2) and exhibits bactericidal activity, and we established compound 1 and ClpP1P2 as an attractive lead/target couple.

Where Have All the Giants Gone? How Animals Deal with the Problem of Size.

The survival of both the hunter and the hunted often comes down to speed. Yet how fast an animal can run is intricately linked to its size, such that the fastest animals are not the biggest nor the smallest. The ability to maintain high speeds is dependent on the body's capacity to withstand the high stresses involved with locomotion.

Pex35 is a regulator of peroxisome abundance.

Peroxisomes are cellular organelles with vital functions in lipid, amino acid and redox metabolism. The cellular formation and dynamics of peroxisomes are governed by genes; however, the regulation of peroxisome abundance is still poorly understood. Here, we use a high-content microscopy screen in to identify new regulators of peroxisome size and abundance.

Kölliker-Fuse nuclei regulate respiratory rhythm variability via a gain-control mechanism.

Respiration varies from breath to breath. On the millisecond timescale of spiking, neuronal circuits exhibit variability due to the stochastic properties of ion channels and synapses. Does this fast, microscopic source of variability contribute to the slower, macroscopic variability of the respiratory period? To address this question, we modeled a stochastic oscillator with forcing; then, we tested its predictions experimentally for the respiratory rhythm generated by the in situ perfused preparation during vagal nerve stimulation (VNS).

Missense Mutations in the Unfoldase ClpC1 of the Caseinolytic Protease Complex Are Associated with Pyrazinamide Resistance in Mycobacterium tuberculosis.

Previously, we showed that mutations in Mycobacterium tuberculosis panD, involved in coenzyme A biosynthesis, cause resistance against pyrazinoic acid, the bioactive component of the prodrug pyrazinamide. To identify additional resistance mechanisms, we isolated mutants resistant against pyrazinoic acid and subjected panD wild-type strains to whole-genome sequencing. Eight of the nine resistant strains harbored missense mutations in the unfoldase ClpC1 associated with the caseinolytic protease complex.

Outcomes of a pharmacist-managed glucose collaborative practice agreement.

Purpose: The impact of a pharmacist-managed glucose collaborative practice agreement (CPA) on glycemic control at a tertiary medical center was investigated.

Methods: A retrospective data analysis was performed on hospitalized, noncritically ill patients admitted between December 2012 and June 2014 who received at least one dose of subcutaneous insulin and experienced at least one blood glucose concentration of 140 mg/dL or higher. The study population was divided into cohorts based on admittance before versus after implementation of the CPA, as well as glucose management by pharmacist versus nonpharmacist provider.

Redox sensitivity of the MyD88 immune signaling adapter.

The transcription factor nuclear factor-κB (NF-κB) mediates expression of key genes involved in innate immunity and inflammation. NF-κB activation has been repeatedly reported to be modulated by hydrogen peroxide (HO). Here, we show that the NF-κB-activating signaling adapter myeloid differentiation primary response gene 88 (MyD88) is highly sensitive to oxidation by HO and may be redox-regulated in its function, thus facilitating an influence of HO on the NF-κB signaling pathway.

Developmental transcriptome of resting cell formation in Mycobacterium smegmatis.

Background: Mycobacteria, along with exospore forming Streptomyces, belong to the phylum actinobacteria. Mycobacteria are generally believed to be non-differentiating. Recently however, we showed that the mycobacterial model organism M.

Quantifying Achilles tendon force in vivo from ultrasound images.

This study evaluated a procedure for estimating in vivo Achilles tendon (AT) force from ultrasound images. Two aspects of the procedure were tested: (i) accounting for subject-specific AT stiffness and (ii) accounting for changes in the relative electromyographic (EMG) intensities of the three triceps surae muscles. Ten cyclists pedaled at 80rpm while a comprehensive set of kinematic, kinetic, EMG, and ultrasound data were collected.

Effects of ion channel noise on neural circuits: an application to the respiratory pattern generator to investigate breathing variability.

Unlabelled: Neural activity generally displays irregular firing patterns even in circuits with apparently regular outputs, such as motor pattern generators, in which the output frequency fluctuates randomly around a mean value. This "circuit noise" is inherited from the random firing of single neurons, which emerges from stochastic ion channel gating (channel noise), spontaneous neurotransmitter release, and its diffusion and binding to synaptic receptors. Here we demonstrate how to expand conductance-based network models that are originally deterministic to include realistic, physiological noise, focusing on stochastic ion channel gating.

Pyrazinamide Resistance Is Caused by Two Distinct Mechanisms: Prevention of Coenzyme A Depletion and Loss of Virulence Factor Synthesis.

Pyrazinamide (PZA) is a critical component of first- and second-line treatments of tuberculosis (TB), yet its mechanism of action largely remains an enigma. We carried out a genetic screen to isolate Mycobacterium bovis BCG mutants resistant to pyrazinoic acid (POA), the bioactive derivative of PZA, followed by whole genome sequencing of 26 POA resistant strains. Rather than finding mutations in the proposed candidate targets fatty acid synthase I and ribosomal protein S1, we found resistance conferring mutations in two pathways: missense mutations in aspartate decarboxylase panD, involved in the synthesis of the essential acyl carrier coenzyme A (CoA), and frameshift mutations in the vitro nonessential polyketide synthase genes mas and ppsA-E, involved in the synthesis of the virulence factor phthiocerol dimycocerosate (PDIM).

C57BL/6J mouse apolipoprotein A2 gene is deterministic for apnea.

Rationale: Brainstem apolipoprotein AII (apoa2) mRNA expression correlates with apnea in breathing present in the adult C57Bl/6J (B6) sleep apnea model.

Objectives: To test the hypothesis that the B6 apoa2 gene contributes to the trait, we performed plethysmographic testing in apoa2 knock out (KO: -/-) mice, an in situ brainstem-spinal cord preparation comparing KO to WT (+/+) mice, and B6xDBA recombinant inbred strains (RISs).

Measurements And Main Results: Apoa2 WT do, but KO and heterozygote (+/-) mice do not exhibit apnea during post-hypoxic breathing, measured in vivo.

Fragment-Based Whole Cell Screen Delivers Hits against M. tuberculosis and Non-tuberculous Mycobacteria.

Reactive multi-target 'fragment drugs' represent critical components of current tuberculosis regimens. These compounds, such as pyrazinamide, are old synthetic antimycobacterials that are activated inside Mycobacterium tuberculosis bacilli and are smaller than the usual drug-like, single-target molecules. Based on the success of small 'dirty' drugs in the chemotherapy of tuberculosis, we suggested previously that fragment-based whole cell screens should be introduced in our current antimycobacterial drug discovery efforts.

Multicenter evaluation of efficacy and safety of low-dose versus high-dose valganciclovir for prevention of cytomegalovirus disease in donor and recipient positive (D+/R+) renal transplant recipients.

Background: The cytomegalovirus (CMV) donor-positive/recipient-positive (D+/R+) population is the largest proportion of renal transplant recipients (RTR). Guidelines for prevention of CMV in the intermediate-risk D+/R+ population include prophylaxis with valganciclovir (VGCV) 900 mg/day for 3 months. This study is the first head-to-head analysis, to our knowledge, comparing the efficacy and safety CMV prophylaxis of VGCV 450 vs 900 mg/day for 3 months in D+/R+ RTR.

Rel Is Required for Morphogenesis of Resting Cells in Mycobacterium smegmatis.

Recently we showed that upon transfer of growing Mycobacterium smegmatis into saline, the bacilli exited the canonical cell division cycle and formed septated multi-nucleoided cells. Under shock starvation (i.e.

Bedaquiline Targets the ε Subunit of Mycobacterial F-ATP Synthase.

The tuberculosis drug bedaquiline inhibits mycobacterial F-ATP synthase by binding to its c subunit. Using the purified ε subunit of the synthase and spectroscopy, we previously demonstrated that the drug interacts with this protein near its unique tryptophan residue. Here, we show that replacement of ε's tryptophan with alanine resulted in bedaquiline hypersusceptibility of the bacteria.

Development and feasibility of an evidence-informed self-management education program in pediatric concussion rehabilitation.

Background: Concussion is a considerable public health problem in youth. However, identifying, understanding and implementing best evidence informed recovery guidelines may be challenging for families given the vast amount of information available in the public domains (e.g.

Amphiphilic xanthones as a potent chemical entity of anti-mycobacterial agents with membrane-targeting properties.

Tuberculosis (TB) remains a deadly disease and infects one-third of the world's population. Given the low success rates encountered in clinical development, there is an urgent need to identify structurally novel antimicrobials for tuberculosis. The present report details the anti-mycobacterial activities, structure-activity relationships (SARs) and mechanism of action of amphiphilic xanthone derivatives.

Mild Nutrient Starvation Triggers the Development of a Small-Cell Survival Morphotype in Mycobacteria.

Mycobacteria, generally believed to be non-sporulating, are well known to survive shock starvation in saline for extended periods of time in a non-replicating state without any apparent morphological changes. Here, we uncover that mycobacteria can undergo cellular differentiation by exposing Mycobacterium smegmatis to mild starvation conditions. Traces of various carbon sources in saline triggered the development of a novel small resting cell (SMRC) morphotype.