Secondary Metabolites in Allergic Plant Pollen Samples Modulate Afferent Neurons and Murine Tracheal Rings.

Plant pollens are strong airborne elicitors of asthma. Their proteinaceous allergens have been studied intensively, but little is known about a possible contribution of pollen secondary metabolites to the nonallergic exacerbation of asthma. Pollen samples originating from 30 plant species were analyzed by HPLC coupled to PDA, ESIMS, and ELSD detectors and off-line NMR spectroscopy.

Automated Comparative Metabolite Profiling of Large LC-ESIMS Data Sets in an ACD/MS Workbook Suite Add-in, and Data Clustering on a New Open-Source Web Platform FreeClust.

The technological development of LC-MS instrumentation has led to significant improvements of performance and sensitivity, enabling high-throughput analysis of complex samples, such as plant extracts. Most software suites allow preprocessing of LC-MS chromatograms to obtain comprehensive information on single constituents. However, more advanced processing needs, such as the systematic and unbiased comparative metabolite profiling of large numbers of complex LC-MS chromatograms remains a challenge.

Dammarane-type saponins from leaves of Ziziphus spina-christi.

Phytochemical profiling of Ziziphus spina-christi leaves led to the characterization of 10 dammarane-type saponins and 12 phenolic compounds. Isolation was achieved by gel chromatography on Sephadex LH20, open column chromatography on silica gel, and semi-preparative HPLC with PDA and ELSD detectors. Structural characterization was performed by extensive 1D and 2D NMR, mass spectrometry, and by GC-MS of sugar derivatives.

Reconstitution of nucleosome demethylation and catalytic properties of a Jumonji histone demethylase.

Jumonji histone demethylases catalyze removal of methyl marks from lysine residues in histone proteins within nucleosomes. Here, we show that the catalytic domain of demethylase JMJD2A (cJMJD2A) utilizes a distributive mechanism to remove the histone H3 lysine 9 trimethyl mark. By developing a method to assess demethylation of homogeneous, site-specifically methylated nucleosomes, we determined that the kinetic parameters for demethylation of nucleosomes by cJMJD2A are comparable to those of peptide substrates.