Objectives
The single‐ and multiple‐dose pharmacokinetics (PK) of tedizolid were examined after oral administration of tedizolid phosphate disodium (TPD), including the effect of food on PK. The ...relative bioavailability of TPD to the free acid tedizolid phosphate was determined to bridge the results of these and other studies to the solid form of the prodrug selected for further development.
Design
Randomized placebo‐controlled, double‐blind single‐ and multiple‐ascending dose studies and randomized open‐label, crossover food effect and relative bioavailability studies.
Setting
Clinical Research Units.
Participants
Healthy subjects.
Intervention
Study TR701‐101 enrolled 40 subjects in single‐ascending dose (200–1200 mg TPD or placebo) and 40 subjects in 21‐day multiple‐ascending dose (200, 300, or 400 mg TPD once/day; 600 mg linezolid twice/day; or placebo) arms. Study TR701‐103 was a food‐effect study in 12 subjects administered 600 mg TPD. Study TR701‐108 was a relative bioavailability study in 12 subjects administered 150‐mg tedizolid equivalents as TPD or tedizolid phosphate.
Measurements and Main Results
Plasma concentrations of the prodrug tedizolid phosphate, its active moiety tedizolid, and/or linezolid were collected. After administration of 200 to 600 mg TPD, tedizolid values increased approximately dose proportionally in area under the concentration‐time curve (AUC) and maximum plasma concentration (Cmax). Tedizolid half‐life values were approximately 2‐fold greater compared with linezolid. TPD administration with food delayed tedizolid absorption and reduced Cmax relative to the fasted state but did not alter AUC. Minimal accumulation was predicted and observed for tedizolid, whereas observed accumulation of linezolid exceeded predictions based on single‐dose PK. Comparable PK of tedizolid was observed following oral administration of either TPD or tedizolid phosphate. In the multiple‐ascending dose study, 3 of 24 tedizolid subjects were withdrawn under prespecified stopping rules (one each of elevated alanine aminotransferase, low reticulocyte count, or low white blood cell count), as was 1 of 8 linezolid subjects (low reticulocyte count).
Conclusions
Overall, tedizolid has a favorable PK profile, a half‐life that supports once daily administration, and no nonlinearities at steady state. Tedizolid phosphate can be administered without regard to food.
Male odors can influence a female's reproductive physiology. In the mouse, the odor of male urine results in an early onset of female puberty. Several volatile and protein pheromones have previously ...been reported to each account for this bioactivity. Here we bioassay inbred BALB/cJ females to study pheromone-accelerated uterine growth, a developmental hallmark of puberty. We evaluate the response of wild-type and mutant mice lacking a specialized sensory transduction channel, TrpC2, and find TrpC2 function to be necessary for pheromone-mediated uterine growth. We analyze the relative effectiveness of pheromones previously identified to accelerate puberty through direct bioassay and find none to significantly accelerate uterine growth in BALB/cJ females. Complementary to this analysis, we have devised a strategy of partial purification of the uterine growth bioactivity from male urine and applied it to purify bioactivity from three different laboratory strains. The biochemical characteristics of the active fraction of all three strains are inconsistent with that of previously known pheromones. When directly analyzed, we are unable to detect previously known pheromones in urine fractions that generate uterine growth. Our analysis indicates that pheromones emitted by males to advance female puberty remain to be identified.
Objectives
Tedizolid phosphate is a novel antibacterial under investigation for the treatment of gram‐positive infections. This study was conducted to assess the pharmacokinetics, safety, and ...tolerability of intravenous tedizolid phosphate as well as the oral bioavailability of tedizolid phosphate.
Design
Double‐blind, single‐ascending dose, multiple‐dose pharmacokinetics study, as well as tolerability and open‐label crossover studies.
Setting
Single center in the United States (Covance Clinical Research Unit, Madison, WI) between September 2009 and January 2010.
Participants
Ninety healthy volunteers.
Intervention
Single intravenous (IV) doses of tedizolid phosphate 50 mg (lead‐in) and 100–400 mg. Single oral and IV dose of tedizolid phosphate 200 mg in crossover fashion. Multiple IV doses of tedizolid phosphate 200 and 300 mg for up to 7 days.
Measurements and Main Results
A dose‐dependent increase was observed in the maximum plasma concentration (1.2–5.1 μg/ml) and the area under the concentration‐time curve (17.4–58.7 μg × hr/ml) of tedizolid (the microbiologically active moiety of tedizolid phosphate) after single IV doses of tedizolid phosphate 100–400 mg. Administration of IV tedizolid phosphate 200 mg once/day for 7 days resulted in minimal (28%) tedizolid accumulation. The absolute oral bioavailability of tedizolid after a single 200‐mg dose of tedizolid phosphate was 91%; pharmacokinetic parameters of tedizolid were similar with oral and IV administration. Treatment‐related adverse events occurred in 41% of subjects. Most adverse events were related to infusion site and became more frequent with multiple dosing. In an additional 3‐day tolerability study, IV tedizolid phosphate 200 mg and placebo were similarly tolerated, based on visual infusion phlebitis scores.
Conclusion
These results from a population of healthy volunteers support once/day dosing of tedizolid phosphate 200 mg with both the oral and IV formulations, without the need for dose adjustment when switching administration routes.
Geobacter species specialize in making electrical contacts with extracellular electron acceptors and other organisms. This permits Geobacter species to fill important niches in a diversity of ...anaerobic environments. Geobacter species appear to be the primary agents for coupling the oxidation of organic compounds to the reduction of insoluble Fe(III) and Mn(IV) oxides in many soils and sediments, a process of global biogeochemical significance. Some Geobacter species can anaerobically oxidize aromatic hydrocarbons and play an important role in aromatic hydrocarbon removal from contaminated aquifers. The ability of Geobacter species to reductively precipitate uranium and related contaminants has led to the development of bioremediation strategies for contaminated environments. Geobacter species produce higher current densities than any other known organism in microbial fuel cells and are common colonizers of electrodes harvesting electricity from organic wastes and aquatic sediments. Direct interspecies electron exchange between Geobacter species and syntrophic partners appears to be an important process in anaerobic wastewater digesters. Functional and comparative genomic studies have begun to reveal important aspects of Geobacter physiology and regulation, but much remains unexplored. Quantifying key gene transcripts and proteins of subsurface Geobacter communities has proven to be a powerful approach to diagnose the in situ physiological status of Geobacter species during groundwater bioremediation. The growth and activity of Geobacter species in the subsurface and their biogeochemical impact under different environmental conditions can be predicted with a systems biology approach in which genome-scale metabolic models are coupled with appropriate physical/chemical models. The proficiency of Geobacter species in transferring electrons to insoluble minerals, electrodes, and possibly other microorganisms can be attributed to their unique "microbial nanowires," pili that conduct electrons along their length with metallic-like conductivity. Surprisingly, the abundant c-type cytochromes of Geobacter species do not contribute to this long-range electron transport, but cytochromes are important for making the terminal electrical connections with Fe(III) oxides and electrodes and also function as capacitors, storing charge to permit continued respiration when extracellular electron acceptors are temporarily unavailable. The high conductivity of Geobacter pili and biofilms and the ability of biofilms to function as supercapacitors are novel properties that might contribute to the field of bioelectronics. The study of Geobacter species has revealed a remarkable number of microbial physiological properties that had not previously been described in any microorganism. Further investigation of these environmentally relevant and physiologically unique organisms is warranted.
Bacterial sporulation allows starving cells to differentiate into metabolically dormant spores that can survive extreme conditions. Following asymmetric division, the mother cell engulfs the ...forespore, surrounding it with two bilayer membranes. During the engulfment process, an essential channel, the so-called feeding tube apparatus, is thought to cross both membranes to create a direct conduit between the mother cell and the forespore. At least nine proteins are required to create this channel, including SpoIIQ and SpoIIIAA-AH. Here, we present the near-atomic resolution structure of one of these proteins, SpoIIIAG, determined by single-particle cryo-EM. A 3D reconstruction revealed that SpoIIIAG assembles into a large and stable 30-fold symmetric complex with a unique mushroom-like architecture. The complex is collectively composed of three distinctive circular structures: a 60-stranded vertical β-barrel that forms a large inner channel encircled by two concentric rings, one β-mediated and the other formed by repeats of a ring-building motif (RBM) common to the architecture of various dual membrane secretion systems of distinct function. Our near-atomic resolution structure clearly shows that SpoIIIAG exhibits a unique and dramatic adaptation of the RBM fold with a unique β-triangle insertion that assembles into the prominent channel, the dimensions of which suggest the potential passage of large macromolecules between the mother cell and forespore during the feeding process. Indeed, mutation of residues located at key interfaces between monomers of this RBM resulted in severe defects both in vivo and in vitro, providing additional support for this unprecedented structure.
Global changes in bacterial gene expression can be orchestrated by the coordinated activation/deactivation of alternative sigma (σ) factor subunits of RNA polymerase. Sigma factors themselves are ...regulated in myriad ways, including via anti-sigma factors. Here, we have determined the solution structure of anti-sigma factor CsfB, responsible for inhibition of two alternative sigma factors, σG and σE, during spore formation by Bacillus subtilis. CsfB assembles into a symmetrical homodimer, with each monomer bound to a single Zn2+ ion via a treble-clef zinc finger fold. Directed mutagenesis indicates that dimer formation is critical for CsfB-mediated inhibition of both σG and σE, and we have characterized these interactions in vitro. This work represents an advance in our understanding of how CsfB mediates inhibition of two alternative sigma factors to drive developmental gene expression in a bacterium.
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•The structure of CsfB is unique among anti-sigma factors•CsfB assembles into a tight homodimer of treble-clef zinc finger domains•CsfB dimerization is essential for inhibition of two alternative sigma factors
Martínez-Lumbreras, Alfano et al. have solved the structure of the anti-sigma factor CsfB and explored its role in inhibiting two alternative sigma factors during Bacillus subtilis spore formation. The results provide insight into the molecular mechanism underlying a gene expression switch in bacteria.
•Behavioral interventions for behavioral and psychological symptoms of dementia are possible in acute care•STAR-VA is applicable to acute care units with minimal modifications needed•Behavioral ...interventions for behavioral and psychological symptoms of dementia increase staff efficacy and confidence responding to and managing distress behaviors in dementia•Behavioral interventions on an acute care unit decrease behavioral rapid responses
As the population grows, the incidence of dementia will increase. A common occurrence in people with dementia is behavioral and psychological symptoms of dementia (BPSD). BPSD can include apathy, aggression, resistance to care, and agitation. BPSD can start or worsen during an acute hospitalization, but these units are not well-equipped to handle BPSD, often relying on pharmacological interventions to address distress behaviors. One known behavioral intervention for BPSD is STAR-VA, an interdisciplinary approach to managing these behaviors. However, this intervention has not been utilized in acute care. Our team implemented STAR-VA in acute care at a Veterans Affairs hospital in the northeastern United States. Using the VA's Quality Enhancement Research Initiative (QUERI) implementation roadmap to guide our work, we first outlined the problem, completed a needs assessment with staff, and began implementation. Results from this quality improvement project demonstrated the feasibility and efficacy of STAR-VA in an acute care setting.
SpoIIQ is an essential component of a channel connecting the developing forespore to the adjacent mother cell during Bacillus subtilis sporulation. This channel is generally required for late gene ...expression in the forespore, including that directed by the late-acting sigma factor σ(G) Here, we present evidence that SpoIIQ also participates in a previously unknown gene regulatory circuit that specifically represses expression of the gene encoding the anti-sigma factor CsfB, a potent inhibitor of σ(G) The csfB gene is ordinarily transcribed in the forespore only by the early-acting sigma factor σ(F) However, in a mutant lacking the highly conserved SpoIIQ transmembrane amino acid Tyr-28, csfB was also aberrantly transcribed later by σ(G), the very target of CsfB inhibition. This regulation of csfB by SpoIIQ Tyr-28 is specific, given that the expression of other σ(F)-dependent genes was unaffected. Moreover, we identified a conserved element within the csfB promoter region that is both necessary and sufficient for SpoIIQ Tyr-28-mediated inhibition. These results indicate that SpoIIQ is a bifunctional protein that not only generally promotes σ(G)activity in the forespore as a channel component but also specifically maximizes σ(G)activity as part of a gene regulatory circuit that represses σ(G)-dependent expression of its own inhibitor, CsfB. Finally, we demonstrate that SpoIIQ Tyr-28 is required for the proper localization and stability of the SpoIIE phosphatase, raising the possibility that these two multifunctional proteins cooperate to fine-tune developmental gene expression in the forespore at late times.
Cellular development is orchestrated by gene regulatory networks that activate or repress developmental genes at the right time and place. Late gene expression in the developing Bacillus subtilis spore is directed by the alternative sigma factor σ(G) The activity of σ(G)requires a channel apparatus through which the adjacent mother cell provides substrates that generally support gene expression. Here we report that the channel protein SpoIIQ also specifically maximizes σ(G)activity as part of a previously unknown regulatory circuit that prevents σ(G)from activating transcription of the gene encoding its own inhibitor, the anti-sigma factor CsfB. The discovery of this regulatory circuit significantly expands our understanding of the gene regulatory network controlling late gene expression in the developing B. subtilis spore.
Mutations in the unc-82 locus of Caenorhabditis elegans were previously identified by screening for disrupted muscle cytoskeleton in otherwise apparently normal mutagenized animals. Here we ...demonstrate that the locus encodes a serine/threonine kinase orthologous to human ARK5/SNARK (NUAK1/NUAK2) and related to the PAR-1 and SNF1/AMP-Activated kinase (AMPK) families. The predicted 1600-amino-acid polypeptide contains an N-terminal catalytic domain and noncomplex repetitive sequence in the remainder of the molecule. Phenotypic analyses indicate that unc-82 is required for maintaining the organization of myosin filaments and internal components of the M-line during cell-shape changes. Mutants exhibit normal patterning of cytoskeletal elements during early embryogenesis. Defects in localization of thick filament and M-line components arise during embryonic elongation and become progressively more severe as development proceeds. The phenotype is independent of contractile activity, consistent with unc-82 mutations preventing proper cytoskeletal reorganization during growth, rather than undermining structural integrity of the M-line. This is the first report establishing a role for the UNC-82/ARK5/SNARK kinases in normal development. We propose that activation of UNC-82 kinase during cell elongation regulates thick filament attachment or growth, perhaps through phosphorylation of myosin and paramyosin. We speculate that regulation of myosin is an ancestral characteristic of kinases in this region of the kinome.
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