Tautomerization and Isomerization in Quantitative NMR: A Case Study with 4-Deoxynivalenol (DON).

The regulated mycotoxin 4-deoxynivalenol (DON) has a heterocyclic structure that is readily amenable to tautomerization and conformational isomerization in solution. An analysis of DON in solution by NMR revealed the presence of hemiacetal tautomer(s) and putative conformational isomers, which maintain the intact enone functional group. The extent and type of tautomerization/isomerization vary according to the NMR solvent used and produce different signal patterns in the NMR spectra.

Improved Isolation Procedures for Okadaic Acid Group Toxins from Shellfish () and Microalgae ().

Okadaic acid (OA) group toxins may accumulate in shellfish and can result in diarrhetic shellfish poisoning when consumed by humans, and are therefore regulated. Purified toxins are required for the production of certified reference materials used to accurately quantitate toxin levels in shellfish and water samples, and for other research purposes. An improved procedure was developed for the isolation of dinophysistoxin-2 (DTX2) from shellfish (), reducing the number of purification steps from eight to five, thereby increasing recoveries to ~68%, compared to ~40% in a previously reported method, and a purity of >95%.

Structure Elucidation and Relative Toxicity of (24)-24-Hydroxyyessotoxin from a Namibian Isolate of .

Liquid chromatography-high-resolution mass spectrometry (LC-HRMS) analysis of a Namibian strain of showed the presence of a number of yessotoxins (YTXs). Principal among these were YTX (), homoYTX (), and a tentative hydroxylated analogue that did not correspond to any previously confirmed YTX structures. Culturing the strain afforded sufficient biomass for purification of the new analogue through a series of solvent partitioning and chromatographic steps, yielding ∼0.

Identification of Host Proteins Predictive of Early Stage Mycobacterium tuberculosis Infection.

The objective of this study was to identify blood-based protein biomarkers of early stage Mycobacterium tuberculosis (Mtb) infection. We utilized plasma and serum specimens from TB patients and their contacts (age≥12) enrolled in a household contact study in Uganda. In the discovery phase cross-sectional samples from 104 HIV-uninfected persons classified as either active TB, latent Mtb infection (LTBI), tuberculin skin test (TST) converters, or persistent TST-negative were analyzed.

Host Protein Biomarkers Identify Active Tuberculosis in HIV Uninfected and Co-infected Individuals.

Biomarkers for active tuberculosis (TB) are urgently needed to improve rapid TB diagnosis. The objective of this study was to identify serum protein expression changes associated with TB but not latent Mycobacterium tuberculosis infection (LTBI), uninfected states, or respiratory diseases other than TB (ORD). Serum samples from 209 HIV uninfected (HIV(-)) and co-infected (HIV(+)) individuals were studied.