Development of a Staphylococcus aureus reporter strain with click beetle red luciferase for enhanced in vivo imaging of experimental bacteremia and mixed infections.

In vivo bioluminescence imaging has been used to monitor Staphylococcus aureus infections in preclinical models by employing bacterial reporter strains possessing a modified lux operon from Photorhabdus luminescens. However, the relatively short emission wavelength of lux (peak 490 nm) has limited tissue penetration. To overcome this limitation, the gene for the click beetle (Pyrophorus plagiophtalamus) red luciferase (luc) (with a longer >600 emission wavelength), was introduced singly and in combination with the lux operon into a methicillin-resistant S.

Experimental and Theoretical Studies on the Aqueous Solvation and Reactivity of SmCl and Comparison with SmBr and SmI.

Water addition to Sm(II) has been shown to increase reactivity for both SmI and SmBr. Previous work in our groups has demonstrated that this increase in reactivity can be attributed to coordination induced bond weakening enabling substrate reduction through proton-coupled electron transfer. The present work examines the interaction of water with samarium dichloride (SmCl) and illustrates the importance of the Sm-X interaction and bond distance upon water addition critical for the reactivity of the reagent system.

Experimental and Theoretical Studies on the Implications of Halide-Dependent Aqueous Solvation of Sm(II).

The addition of water to samarium(II) has been demonstrated to have a significant impact on the reduction of organic substrates, with the majority of research dedicated to the most widely used reagent, samarium diiodide (SmI). The work presented herein focuses on the reducing capabilities of samarium dibromide (SmBr) and demonstrates how the modest change in halide ligand results in observable mechanistic differences between the SmBr-water and the SmI-water systems that have considerable implications in terms of reactivity between the two reagents. Quantum chemical results from Born-Oppenheimer molecular dynamics simulations show significant differences between SmI-water and SmBr-water, with the latter displaying less dissociation of the halide, which results in a lower coordination number for water.

Interplay between Substrate and Proton Donor Coordination in Reductions of Carbonyls by SmI-Water Through Proton-Coupled Electron-Transfer.

The reduction of a carbonyl by SmI-water is the first step in a range of reactions of synthetic importance. Although the reduction is often proposed to proceed through an initial stepwise electron-transfer-proton-transfer (ET-PT), recent work has shown that carbonyls and related functional groups are likely reduced though proton-coupled electron-transfer (PCET). In the present work, the reduction of an activated ester, aldehyde, a linear and cyclic ketone, and related sterically demanding carbonyls by SmI-HO was examined through a series of mechanistic experiments.

Secondary Amides as Hydrogen Atom Transfer Promoters for Reactions of Samarium Diiodide.

Two secondary amides (N-methylacetamide and 2-pyrrolidinone) were used as additives with SmI in THF to estimate the extent of N-H bond weakening upon coordination. Mechanistic and synthetic studies demonstrate significant bond-weakening, providing a reagent system capable of reducing a range of substrates through formal hydrogen atom transfer.

Proton-Coupled Electron Transfer in the Reduction of Carbonyls by Samarium Diiodide-Water Complexes.

Reduction of carbonyls by SmI2 is significantly impacted by the presence of water, but the fundamental step(s) of initial transfer of a formal hydrogen atom from the SmI2-water reagent system to produce an intermediate radical is not fully understood. In this work, we provide evidence consistent with the reduction of carbonyls by SmI2-water proceeding through proton-coupled electron transfer (PCET). Combined rate and computational studies show that a model aldehyde and ketone are likely reduced through an asynchronous PCET, whereas reduction of a representative lactone occurs through a concerted PCET.

High-Affinity Proton Donors Promote Proton-Coupled Electron Transfer by Samarium Diiodide.

The relationship between proton-donor affinity for Sm(II) ions and the reduction of two substrates (anthracene and benzyl chloride) was examined. A combination of spectroscopic, thermochemical, and kinetic studies show that only those proton donors that coordinate or chelate strongly to Sm(II) promote anthracene reduction through a PCET process. These studies demonstrate that the combination of Sm(II) ions and water does not provide a unique reagent system for formal hydrogen atom transfer to substrates.

Detection of monofluoroacetate in Palicourea and Amorimia species.

Numerous plant species worldwide including Palicourea marcgravii and Tanaecium bilabiatum in Brazil cause sudden death and are known to contain monofluoroacetate (MFA). Other species in Brazil including some species traditionally assigned to Mascagnia but now properly called Amorimia species and other Palicourea species are reported to cause sudden death in livestock and are suspected to contain MFA due to the similarity of clinical signs. In this study, an HPLC-APCI-MS method to detect and quantify MFA was developed and was used to investigate plant material from field collections and/or herbarium specimens of Mascagnia, Amorimia, and Palicourea species suspected of causing sudden death.

A complete generic phylogeny of Malpighiaceae inferred from nucleotide sequence data and morphology.

Premise Of The Study: The Malpighiaceae include ∼1300 tropical flowering plant species in which generic definitions and intergeneric relationships have long been problematic. The goals of our study were to resolve relationships among the 11 generic segregates from the New World genus Mascagnia, test the monophyly of the largest remaining Malpighiaceae genera, and clarify the placement of Old World Malpighiaceae. •

Methods: We combined DNA sequence data for four genes (plastid ndhF, matK, and rbcL and nuclear PHYC) from 338 ingroup accessions that represented all 77 currently recognized genera with morphological data from 144 ingroup species to produce a complete generic phylogeny of the family.

Gene transfer from a parasitic flowering plant to a fern.

The rattlesnake fern (Botrychium virginianum (L.) Sw.) is obligately mycotrophic and widely distributed across the northern hemisphere.

Accuracy of Nanoscale Pitch Standards Fabricated by Laser-Focused Atomic Deposition.

The pitch accuracy of a grating formed by laser-focused atomic deposition is evaluated from the point of view of fabricating nanoscale pitch standard artifacts. The average pitch obtained by the process, nominally half the laser wavelength, is simply traceable with small uncertainty to an atomic frequency and hence can be known with very high accuracy. An error budget is presented for a Cr on sapphire sample, showing that a combined standard uncertainty of 0.

Epirubicin and meglumine gamma-linolenic acid: a logical choice of combination therapy for patients with superficial bladder carcinoma.

Background: Anthracyclines have been established as first-line drugs for intravesical use in the treatment of patients with superficial bladder carcinoma, although they result only in a modest reduction in tumor recurrence rates. The essential fatty acid gamma-linolenic acid (GLA) also is an effective cytotoxic agent against superficial bladder carcinoma when it is applied topically. The objective of this study was to assess the efficacy of combined epirubicin and GLA with the purpose of developing a suitable model for modification of existing intravesical regimens.

Occurrence and phylogenetic significance of latex in the Malpighiaceae.

Latex and laticifers are reported for the first time in the genera Galphimia and Verrucularia (Malpighiaceae), with description and illustration of the leaf and stem anatomy of both genera. Those genera and the other two in which latex is known (Lophanthera and Spachea) constitute a single tribe, Galphimieae, that is at or near the base of the family's phylogeny, which suggests that latex in the Malpighiaceae may indicate an ancestor shared with the Euphorbiaceae.