Characterization of three Francisella tularensis genomes from Oklahoma, USA.

Francisella tularensis , the causative agent for tularaemia, is a Tier 1 select agent, and a pan-species pathogen of global significance due to its zoonotic potential. Consistent genome characterization of the pathogen is essential to identify novel genes, virulence factors, antimicrobial resistance genes, for studying phylogenetics and other features of interest. This study was conducted to understand the genetic variations among genomes of F. tularensis isolated from two felines and one human source. Pan-genome analysis revealed that 97.7 % of genes were part of the core genome. All three F. tularensis isolates were assigned to sequence type A based on single nucleotide polymorphisms (SNPs) in sdhA. Most of the virulence genes were part of the core genome. An antibiotic resistance gene coding for class A beta-lactamase was detected in all three isolates. Phylogenetic analysis showed that these isolates clustered with other isolates reported from Central and South-Central USA. Assessment of large sets of the F. tularensis genome sequences is essential in understanding pathogen dynamics, geographical distribution and potential zoonotic implications.

Linear and Radial Conjugation in Extended π-Electron Systems.

We describe the synthesis and electronic properties of new π-conjugated small molecules and polymers that combine the linear intramolecular conjugation pathways commonly associated with organic electronic materials with the emerging properties of radial conjugation found in cycloparaphenylenes (CPPs) and other curved π-surfaces. Using arylene ethynylenes as prototypical linear segments and [6]/[8]CPP as the radial segments, we demonstrate the formation of new electronic states that are not simply additive responses from the individual components. Quantum chemical calculations of model oligomeric structures reveal these electronic processes to arise from the hybrid nature of wave function delocalization over the linear and radial contributors in the photophysically relevant electronic states.

Nanopore ultra-long read sequencing technology for antimicrobial resistance detection in Mannheimia haemolytica.

Disruptive innovations in long-range, cost-effective direct template nucleic acid sequencing are transforming clinical and diagnostic medicine. A multidrug resistant strain and a pan-susceptible strain of Mannheimia haemolytica, isolated from pneumonic bovine lung samples, were sequenced at 146× and 111× coverage, respectively with Oxford Nanopore Technologies MinION. De novo assembly produced a complete genome for the non-resistant strain and a nearly complete assembly for the drug resistant strain. Functional annotation using RAST (Rapid Annotations using Subsystems Technology), CARD (Comprehensive Antibiotic Resistance Database) and ResFinder databases identified genes conferring resistance to different classes of antibiotics including ß-lactams, tetracyclines, lincosamides, phenicols, aminoglycosides, sulfonamides and macrolides. Resistance phenotypes of the M. haemolytica strains were determined by minimum inhibitory concentration (MIC) of the antibiotics. Sequencing with a highly portable MinION device corresponded to MIC assays with most of the antimicrobial resistant determinants being identified with as few as 5437 reads, except for the genes responsible for resistance to Fluoroquinolones. The resulting quality assemblies and AMR gene annotation highlight the efficiency of ultra-long read, whole-genome sequencing (WGS) as a valuable tool in diagnostic veterinary medicine.

Whole-Genome Sequence of Multidrug-Resistant Bibersteinia trehalosi Strain OADDL-BT1.

The genome of a multidrug-resistant strain of Bibersteinia trehalosi isolated from a calf with chronic pneumonia is presented. The draft genome sequences have been deposited at DDBJ/ENA/GenBank.