The use of ultrasound for the extraction of bioactive principles from plant materials

The paper presents our results concerning the ultrasonically assisted extraction of bioactive principles from plant material. A comparison with classical methodologies is presented and technological aspects of ultrasonically assisted extraction are discussed.     

Effect of ultrasound on the immunogenic corn cob xylan

Changes in the structural, molecular and functional properties of the immunogenic corn cob xylan evoked by ultrasonication in water, 1% NaOH and 5% NaOH were investigated. The reduction of the high molar mass (MM) fraction was more intense than that of the medium MM fraction, depending on the sonic power, sonication time, and alkali concentration. The chain degradation was more effective in the alkaline media. The UV-absorbing component, accompanying the xylan polymers in the whole MM range, showed an accumulation in the high MM region as well as shiftening to higher sizes, particularly in 5% NaOH. The sugar composition and primary structure of the xylan was almost retained under all irradiation conditions studied. Although the biological activity of the xylan was affected by the ultrasound, no significant decrease of the biological response was found at short irradiation time and low sonic power.     

Automated immobilized metal affinity chromatography/nano-liquid chromatography/electrospray ionization mass spectrometry platform for profiling protein phosphorylation sites

A versatile integrated system has been developed for the automated enrichment and analysis of phosphopeptides by immobilized metal affinity chromatography/nano-liquid chromatography/electrospray ionization mass spectrometry (IMAC/nano-LC/ESI-MS). This system utilizes two independently controlled high-performance liquid chromatography (HPLC) pumps, an autosampler and microvalves to prepare and elute samples into an ion trap mass spectrometer. The use of robust reversed-phase HPLC columns with integrated ESI emitter tips enables the reproducible detection and identification of low-femtomole quantities of phosphopeptides. The entire system is coordinated through a simple user interface by customized software. The ruggedness of the system is demonstrated by highly reproducible analyses of single and multi-protein digests, while its utility is demonstrated by the thorough evaluation of the relative immunoprecipitation efficiencies of several commercially available anti-phosphotyrosine antibodies.     

Highly efficient and direct heterocyclization of dipyridyl ketone to N,N-bidentate ligands

[reaction: see text] Reaction of various aromatic aldehydes with 2,2'-dipyridyl ketone and ammonium acetate in hot acetic acid provides ready access to a series of substituted 1-pyridylimidazo[1,5-a]pyridines, a class of ligands possessing an N,N-bidentate feature, in good yields.