tRNA has an unusually short half-life in .

Following transcription, tRNAs undergo a series of processing and modification events to become functional adaptors in protein synthesis. Eukaryotes have also evolved intracellular transport systems whereby nucleus-encoded tRNAs may travel out and into the nucleus. In trypanosomes, nearly all tRNAs are also imported from the cytoplasm into the mitochondrion, which lacks tRNA genes.

Loss of a Cardiolipin Synthase in G27 Blocks Flagellum Assembly.

uses a cluster of polar, sheathed flagella for motility, which it requires for colonization of the gastric epithelium in humans. As part of a study to identify factors that contribute to localization of the flagella to the cell pole, we disrupted a gene encoding a cardiolipin synthase () in strains G27 and B128. Flagellum biosynthesis was abolished in the G27 mutant but not in the B128 mutant.

AlmG, responsible for polymyxin resistance in pandemic , is a glycyltransferase distantly related to lipid A late acyltransferases.

Cationic antimicrobial peptides (CAMPs), such as polymyxins, are used as a last-line defense in treatment of many bacterial infections. However, some bacteria have developed resistance mechanisms to survive these compounds. Current pandemic O1 biotype El Tor is resistant to polymyxins, whereas a previous pandemic strain of the biotype Classical is polymyxin-sensitive.

Novel coordination of lipopolysaccharide modifications in Vibrio cholerae promotes CAMP resistance.

In the environment and during infection, the human intestinal pathogen Vibrio cholerae must overcome noxious compounds that damage the bacterial outer membrane. The El Tor and classical biotypes of O1 V. cholerae show striking differences in their resistance to membrane disrupting cationic antimicrobial peptides (CAMPs), such as polymyxins.

Clinical impact of pharmacogenetic profiling with a clinical decision support tool in polypharmacy home health patients: A prospective pilot randomized controlled trial.

Background: In polypharmacy patients under home health management, pharmacogenetic testing coupled with guidance from a clinical decision support tool (CDST) on reducing drug, gene, and cumulative interaction risk may provide valuable insights in prescription drug treatment, reducing re-hospitalization and emergency department (ED) visits. We assessed the clinical impact of pharmacogenetic profiling integrating binary and cumulative drug and gene interaction warnings on home health polypharmacy patients.

Methods And Findings: This prospective, open-label, randomized controlled trial was conducted at one hospital-based home health agency between February 2015 and February 2016.

The Power of Asymmetry: Architecture and Assembly of the Gram-Negative Outer Membrane Lipid Bilayer.

Determining the chemical composition of biological materials is paramount to the study of natural phenomena. Here, we describe the composition of model gram-negative outer membranes, focusing on the predominant assembly, an asymmetrical bilayer of lipid molecules. We also give an overview of lipid biosynthetic pathways and molecular mechanisms that organize this material into the outer membrane bilayer.

UVliPiD: A UVPD-Based Hierarchical Approach for De Novo Characterization of Lipid A Structures.

The lipid A domain of the endotoxic lipopolysaccharide layer of Gram-negative bacteria is comprised of a diglucosamine backbone to which a variable number of variable length fatty acyl chains are anchored. Traditional characterization of these tails and their linkages by nuclear magnetic resonance (NMR) or mass spectrometry is time-consuming and necessitates databases of pre-existing structures for structural assignment. Here, we introduce an automated de novo approach for characterization of lipid A structures that is completely database-independent.

The Vibrio cholerae VprA-VprB two-component system controls virulence through endotoxin modification.

Unlabelled: The bacterial cell surface is the first structure the host immune system targets to prevent infection. Cationic antimicrobial peptides of the innate immune system bind to the membrane of Gram-negative pathogens via conserved, surface-exposed lipopolysaccharide (LPS) molecules. We recently reported that modern strains of the global intestinal pathogen Vibrio cholerae modify the anionic lipid A domain of LPS with a novel moiety, amino acids.

LcrV delivered via type III secretion system of live attenuated Yersinia pseudotuberculosis enhances immunogenicity against pneumonic plague.

Here, we constructed a Yersinia pseudotuberculosis mutant strain with arabinose-dependent regulated and delayed shutoff of crp expression (araC P(BAD) crp) and replacement of the msbB gene with the Escherichia coli msbB gene to attenuate it. Then, we inserted the asd mutation into this construction to form χ10057 [Δasd-206 ΔmsbB868::P(msbB) msbB(EC) ΔP(crp21)::TT araC P(BAD) crp] for use with a balanced-lethal Asd-positive (Asd(+)) plasmid to facilitate antigen synthesis. A hybrid protein composed of YopE (amino acids [aa]1 to 138) fused with full-length LcrV (YopE(Nt138)-LcrV) was synthesized in χ10057 harboring an Asd(+) plasmid (pYA5199, yopE(Nt138)-lcrV) and could be secreted through a type III secretion system (T3SS) in vitro and in vivo.

Antimicrobial peptide resistance of Vibrio cholerae results from an LPS modification pathway related to nonribosomal peptide synthetases.

The current pandemic El Tor biotype of O1 Vibrio cholerae is resistant to polymyxins, whereas the previous pandemic strain of the classical biotype is polymyxin sensitive. The almEFG operon found in El Tor V. cholerae confers >100-fold resistance to polymyxins through the glycylation of lipopolysaccharide.

193 nm ultraviolet photodissociation mass spectrometry for the structural elucidation of lipid A compounds in complex mixtures.

Here we implement ultraviolet photodissociation (UVPD) in an online liquid chromatographic tandem mass spectrometry (MS/MS) strategy to support analysis of complex mixtures of lipid A combinatorially modified during development of vaccine adjuvants. UVPD mass spectrometry at 193 nm was utilized to characterize the structures and fragment ion types of lipid A from Escherichia coli, Vibrio cholerae, and Pseudomonas aeruginosa using an Orbitrap mass spectrometer. The fragment ions generated by UVPD were compared to those from collision induced dissociation (CID) and higher energy collision dissociation (HCD) with respect to the precursor charge state.

Isolation and chemical characterization of lipid A from gram-negative bacteria.

Lipopolysaccharide (LPS) is the major cell surface molecule of gram-negative bacteria, deposited on the outer leaflet of the outer membrane bilayer. LPS can be subdivided into three domains: the distal O-polysaccharide, a core oligosaccharide, and the lipid A domain consisting of a lipid A molecular species and 3-deoxy-D-manno-oct-2-ulosonic acid residues (Kdo). The lipid A domain is the only component essential for bacterial cell survival.

Unexpected expansion of tRNA substrate recognition by the yeast m1G9 methyltransferase Trm10.

N-1 Methylation of the nearly invariant purine residue found at position 9 of tRNA is a nucleotide modification found in multiple tRNA species throughout Eukarya and Archaea. First discovered in Saccharomyces cerevisiae, the tRNA methyltransferase Trm10 is a highly conserved protein both necessary and sufficient to catalyze all known instances of m1G9 modification in yeast. Although there are 19 unique tRNA species that contain a G at position 9 in yeast, and whose fully modified sequence is known, only 9 of these tRNA species are modified with m1G9 in wild-type cells.

Tourism crises and island destinations: Experiences in Penang, Malaysia.

Crisis management and tourism is attracting increasing attention as an industry practice and subject of academic enquiry, not least in South East Asia which has been affected by a number of severe crises in recent years. However, organisations are not always well prepared and response strategies can be deficient. The paper discusses issues of tourism crisis management with specific reference to the popular Malaysian destination of Penang.

Anthracene-bridged binuclear ruthenium complexes: electrochemical and spectroscopic evidence of electronic communication through the pi system.

Six dinuclear cyclometalated ruthenium complexes, 1-6, based on diphenylanthracene (DPA) and anthracene (AN) as bridging ligands have been synthesized and fully characterized electrochemically and spectroscopically. The anodic electrochemistry of the homobinuclear ruthenium complexes, 1-6, has been examined in three different nonaqueous solvents (ACN, DMF, and CH(2)Cl(2)). The ability of the anthracene derivatives to transmit electronic effects between the two redox units has been demonstrated by the observed splitting of the voltammetric signals ascribed to the metal centers.

Transition-metal tris-bipyridines containing three dithienylcyclopentenes: synthesis, photochromic, and electrochromic properties.

Designed prototype molecules for making a three-terminal single-molecule device, star-shaped Fe(II), Co(II), and Ru(II) tris-bipyridine complexes containing three dithienylcyclopentenes, have been synthesized and characterized. All complexes displayed reversible photochromic behavior when irradiated with UV or visible light. The open form of these complexes could be cyclized electrochemically as revealed by cyclic voltammetric studies and bulk electrolysis experiments.

Dithienylcyclopentenes-containing transition metal bisterpyridine complexes directed toward molecular electronic applications.

There is continuing interest in the design and synthesis of functional materials for applications in molecular electronics and information storage. Of particular interest are systems that can provide multiple means for controlling transport through well-defined and stable electronic and/or redox states. We report herein the synthesis and characterization of a system containing transition-metal complexes along with dithienylethene (DTE) units so as to achieve photo and redox control of transport.

Rabies virus in raccoons, Ohio, 2004.

In 2004, the raccoon rabies virus variant emerged in Ohio beyond an area where oral rabies vaccine had been distributed to prevent westward spread of this variant. Our genetic investigation indicates that this outbreak may have begun several years before 2004 and may have originated within the vaccination zone.

Dinuclear transition-metal terpyridine complexes with a dithienylcyclo- pentene bridge directed toward molecular electronic applications.

A series of dinuclear metal terpyridine (M-tpy; M = Ru, Os, Fe, and Co) complexes with a photochromic dithienylethene bridge were designed and synthesized through either a convergent or a divergent approach. The open forms of the complexes containing RuII and FeII centers were found to be inert to ultraviolet photoirradiation but could be cyclized electrochemically as revealed by a cyclic voltammetric study. On the contrary, the CoII complex underwent efficient photochemical but not electrochemical cyclization.

A high-resolution genetic signature of demographic and spatial expansion in epizootic rabies virus.

Emerging pathogens potentially undergo rapid evolution while expanding in population size and geographic range during the course of invasion, yet it is generally difficult to demonstrate how these processes interact. Our analysis of a 30-yr data set covering a large-scale rabies virus outbreak among North American raccoons reveals the long lasting effect of the initial infection wave in determining how viral populations are genetically structured in space. We further find that coalescent-based estimates derived from the genetic data yielded an amazingly accurate reconstruction of the known spatial and demographic dynamics of the virus over time.

Elucidation of the redox behavior of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) at poly(3,4-ethylenedioxythiophene) (PEDOT)-modified electrodes and application of the DMcT-PEDOT composite cathodes to lithium/lithium ion batteries.

The redox reactions of DMcT at PEDOT-modified glassy carbon electrodes (GCEs) in acetonitrile (AN) have been investigated via cyclic voltammetry (CV) and the electrochemical quartz crystal microbalance (EQCM) in order to elucidate the redox reaction mechanism. A redox couple at -0.29 V versus Ag/Ag+ was assigned to the dimerization process of singly protonated DMcT (DMcT-1H), and a second couple observed at +0.

Unifying the spatial population dynamics and molecular evolution of epidemic rabies virus.

Infectious disease emergence is under the simultaneous influence of both genetic and ecological factors. Yet, we lack a general framework for linking ecological dynamics of infectious disease with underlying molecular and evolutionary change. As a model, we illustrate the linkage between ecological and evolutionary dynamics in rabies virus during its epidemic expansion into eastern and southern Ontario.