Combined thin-layer chromatography and mass spectrometry for the screening of pesticides in samples derived from biological origins.

This study describes a method for off-line coupling of thin-layer chromatography (TLC) with electron impact ionization (El)-mass spectrometry for routine determination of pesticides in toxicology and forensic medicine. Six TLC solvent systems are described for 151 different pesticides, and 8-peak mass-spectra generated from full El mass spectra are listed.

Oxidized plant sterols in human serum and lipid infusions as measured by combined gas-liquid chromatography-mass spectrometry.

Some oxidized forms of cholesterol (oxysterols) are thought to be atherogenic and cytotoxic. Because plant sterols are structurally related to cholesterol, we examined whether oxidized plant sterols (oxyphytosterols) could be identified in human serum and soy-based lipid emulsions. We first prepared both deuterated and nondeuterated reference compounds.

Nocardia abscessus sp. nov.

Chemotaxonomic and 16S rRNA gene sequence analyses of four bacterial strains isolated from clinical material clearly demonstrated that these bacteria belong to the genus Nocardia. DNA-DNA hybridization data as well as the physiological characteristics of the isolates indicated that they are closely related and belong to a single species that differs from previously described members of the genus. The name Nocardia abscessus sp.

Nocardia paucivorans sp. nov.

Chemotaxonomic and 16S rDNA sequence analyses of an isolate from the sputa and bronchial secretions of a patient with chronic lung disease clearly demonstrated that it belongs to the genus Nocardia. DNA-DNA hybridization data, as well as the biochemical characteristics of the isolate, indicate that it belongs to a new species that differs from previously described members of the genus Nocardia. The name Nocardia paucivorans sp.

Tsukamurella tyrosinosolvens sp. nov.

Chemotaxonomic and 16S ribosomal DNA sequence analyses of four bacterial isolates from blood cultures from patients with cardiac pacemaker implants and sputa of patients with chronic lung infections clearly demonstrated that these bacteria belong to the genus Tsukamurella. DNA-DNA hybridization data, as well as the physiological characteristics of the isolates, indicate that they are closely related and belong to a single species that differs from previously described members of the genus Tsukamurella. The name Tsukamurella tyrosinosolvens sp.