A Protocol for GC-MS Profiling of Chiral Secondary Amino Acids.

A simple analytical workflow is described for gas chromatographic-mass spectrometric (GC-MS)-based chiral profiling of secondary amino acids (AAs) in biological matrices. The sample preparation is carried out directly in aqueous biological sample extracts and involves in situ heptafluorobutyl chloroformate (HFBCF) derivatization-liquid-liquid microextraction of nonpolar products into hexane phase followed by subsequent formation of the corresponding methylamides from the HFB esters by direct treatment with methylamine reagent solution. The (O, N) HFB-butoxycarbonyl-methylamide AA products (HFBOC-MA) are separated on a Chirasil-L-Val capillary column and quantitatively measured by GC-MS operated in selected ion monitoring (SIM) mode.

Discovery of nostatin A, an azole-containing proteusin with prominent cytostatic and pro-apoptotic activity.

Ribosomally synthesized and post-translationally modified peptides (RiPPs) are intriguing compounds with potential pharmacological applications. While many RiPPs are known as antimicrobial agents, a limited number of RiPPs with anti-proliferative effects in cancer cells are available. Here we report the discovery of nostatin A (NosA), a highly modified RiPP belonging among nitrile hydratase-like leader peptide RiPPs (proteusins), isolated from a terrestrial cyanobacterium sp.

Fipronil prevents transmission of Lyme disease spirochetes.

Lyme disease, a tick-borne illness caused by spirochetes, poses a significant threat to public health. While acaricides effectively control ticks on pets and livestock, their impact on pathogen transmission is often unclear. This study investigated the acaricidal efficacy of fipronil against ticks and its potential to block transmission.

Cepathiolactols and Cepathiolactones─Two Newly Discovered Families of Organosulfur Compounds Formed in Cut Onion.

Isolation and structural characterization of two large families of organosulfur compounds spontaneously formed upon cutting of onion () were carried out. The structures of these hitherto unknown species, trivially named cepathiolactols and cepathiolactones, were established based on NMR, MS, and IR data. It was found that cepathiolactols (CHOS and CHOS; = 7-12, = 14-24) are 3,4-dimethyl-γ-thiolactols bearing various side chains linked via a disulfanyl moiety at position C-5.

Trans-arterial embolization for treatment of acute lower gastrointestinal bleeding-a multicenter analysis.

Purpose: To assess the technical feasibility, safety, and clinical success rate of trans-arterial embolization (TAE) as an emergency treatment for acute lower gastrointestinal bleeding (LGIB).

Materials And Methods: Consecutive patients who received urgent TAE due to active LGIB at five academic centers in Germany were retrospectively analyzed. LGIB was confirmed and localized using contrast-enhanced computed tomography (CT) or endoscopy.