Impact of Chlorine Substitution on Electron Spin Relaxation of a Trityl Radical.

A perchlorotriarylmethyl tricarboxylic acid radical 99% enriched in C at the central carbon (C-PTMTC) was characterized in phosphate buffered saline solution (pH = 7.2) (PBS) at ambient temperature. Samples immobilized in 1:1 PBS:glycerol or in 9:1 trehalose:sucrose were studied as a function of temperature.

Perchlorinated Triarylmethyl Radical 99% Enriched C at the Central Carbon as EPR Spin Probe Highly Sensitive to Molecular Tumbling.

Soluble stable radicals are used as spin probes and spin labels for in vitro and in vivo electron paramagnetic resonance (EPR) spectroscopy and imaging applications. We report the synthesis and characterization of a perchlorinated triarylmethyl radical enriched 99% at the central carbon, . The anisotropy of the hyperfine splitting with the C ( = 26, = 25, = 199.

Composable Microfluidic Plates (cPlate): A Simple and Scalable Fluid Manipulation System for Multiplexed Enzyme-Linked Immunosorbent Assay (ELISA).

Enzyme-linked immunosorbent assay (ELISA) is the gold standard method for protein biomarkers. However, scaling up ELISA for multiplexed biomarker analysis is not a trivial task due to the lengthy procedures for fluid manipulation and high reagent/sample consumption. Herein, we present a highly scalable multiplexed ELISA that achieves a similar level of performance to commercial single-target ELISA kits as well as shorter assay time, less consumption, and simpler procedures.

Acoustofluidic enzyme-linked immunosorbent assay (ELISA) platform enabled by coupled acoustic streaming.

Bead-based ELISA in microfluidics is a promising platform for reducing the reagent consumption and improving assay throughput due to its fast binding kinetics and low reagent consumption. Current microfluidic bead-based immunoassay mainly relies on magnetic and centrifugal forces to manipulate microparticles to complete an assay protocol. Here we report an acoustic streaming-based microfluidic method that can perform all the fluid and particle operations of bead-based ELISA.

Synthesis of hydroxyethyl tetrathiatriarylmethyl radicals OX063 and OX071.

We report the synthesis of hydroxyethyl tetrathiatriarylmethyl radical and its deuterated analogue for biomedical EPR applications.

Unusual acylation of chloramphenicol in Lysobacter enzymogenes, a biocontrol agent with intrinsic resistance to multiple antibiotics.

Background: The environmental gliding bacteria Lysobacter are emerging as a new group of biocontrol agents due to their prolific production of lytic enzymes and potent antibiotic natural products. These bacteria are intrinsically resistant to many antibiotics, but the mechanisms behind the antibiotic resistance have not been investigated.

Results: Previously, we have used chloramphenicol acetyltransferase gene (cat) as a selection marker in genetic manipulation of natural product biosynthetic genes in Lysobacter, because chloramphenicol is one of the two common antibiotics that Lysobacter are susceptible to.

An examination of endoparasites and fecal testosterone levels in flying squirrels ( spp.) using high performance liquid chromatography-ultra-violet (HPLC-UV).

The immuno-competence hypothesis proposes that higher levels of testosterone increases the susceptibility to parasitism. Here we examined the testosterone levels in two species of flying squirrels (): one known to regularly host a nematode species () without ill effects () and a closely related species that is considered negatively affected by the parasite. We quantified fecal testosterone levels in northern and southern flying squirrels () with high-performance liquid chromatography-ultraviolet spectroscopy (HPLC-UV), and compared levels to endoparasites detected in individual squirrels.

Identification of a small molecule signaling factor that regulates the biosynthesis of the antifungal polycyclic tetramate macrolactam HSAF in Lysobacter enzymogenes.

Lysobacter species are emerging as new sources of antibiotics. The regulation of these antibiotics is not well understood. Here, we identified a small molecule metabolite (LeDSF3) that regulates the biosynthesis of the antifungal antibiotic heat-stable antifungal factor (HSAF), a polycyclic tetramate macrolactam with a structure and mode of action distinct from the existing antifungal drugs.

Transcriptomic analysis reveals new regulatory roles of Clp signaling in secondary metabolite biosynthesis and surface motility in Lysobacter enzymogenes OH11.

Lysobacter enzymogenes is a bacterial biological control agent emerging as a new source of antibiotic metabolites, such as heat-stable antifungal factor (HSAF) and the antibacterial factor WAP-8294A2. The regulatory mechanism(s) for antibiotic metabolite biosynthesis remains largely unknown in L. enzymogenes.

Recent advancements in the biosynthetic mechanisms for polyketide-derived mycotoxins.

Polyketides (PKs) are a large group of natural products produced by microorganisms and plants. They are biopolymers of acetate and other short carboxylates and are biosynthesized by multifunctional enzymes called polyketide synthases (PKSs). This review discusses the biosynthesis of four toxic PK, aflatoxins, fumonisins, ochratoxins (OTs), and zearalenone.

Structure and biosynthesis of heat-stable antifungal factor (HSAF), a broad-spectrum antimycotic with a novel mode of action.

A screen for antifungal compounds from Lysobacter enzymogenes strain C3, a bacterial biological control agent of fungal diseases, has previously led to the isolation of heat-stable antifungal factor (HSAF). HSAF exhibits inhibitory activities against a wide range of fungal species and shows a novel mode of antifungal action by disrupting the biosynthesis of a distinct group of sphingolipids. We have now determined the chemical structure of HSAF, which is identical to that of dihydromaltophilin, an antifungal metabolite with a unique macrocyclic lactam system containing a tetramic acid moiety and a 5,5,6-tricyclic skeleton.

Isolation, structure elucidation, and biological evaluation of 15-amido-3-demethoxy-2alpha,3alpha-methylenedioxyerythroculine, a new alkaloid from Hyperbaena valida.

A phytochemical investigation of the leaves of Hyperbaena valida resulted in the isolation and characterization of two erythrina-type alkaloids, 1 and 2, which were found to be antagonists at nicotinic receptors. Compound 1 was assigned as the new 15-amido-3-demethoxy-2alpha,3alpha-methylenedioxyerythroculine and compound 2 as the known 3-demethoxy-2alpha,3alpha-methylenedioxyerythroculine. Antagonism of a 100 microM nicotine response was observed for alkaloid 1 (IC50 value of 94 +/- 8 microM) and alkaloid 2 (IC50 value of 77 +/- 19 microM).