In JoVE (1)

Other Publications (2)

Articles by Elmar C. Fuchs in JoVE

Other articles by Elmar C. Fuchs on PubMed

Structural and Immunological Properties of Arabinogalactan Polysaccharides from Pollen of Timothy Grass (Phleum Pratense L.)

Carbohydrate Research. Mar, 2005  |  Pubmed ID: 15721337

Extracts from pollen of timothy grass (Phleum pratense L.) contain up to 20% arabinogalactan proteins (AGPs). Separation of the AGP polysaccharide moieties by tryptic digestion, size exclusion chromatography (GPC), and reverse phase HPLC yielded arabinogalactan fractions AG-1 and AG-2 with molecular weights of approximately 15,000 and approximately 60,000Da, respectively. The backbones of both polysaccharides are composed of (1-->6)-linked beta-D-galactopyranosides with beta-D-GlcUAp or 4-O-Me-beta-D-GlcUAp at their terminal ends as revealed by chemical analysis, FT-IR, MALDI-MS, and NMR spectroscopy. AG-1 contains a small number of beta-l-Araf side chains while AG-2 possesses a variety of (1-->3)-linked units, which consist of beta-l-Araf-(1-->, alpha-l-Araf-(1-->3)-beta-l-Araf-(1-->, and alpha-l-Araf-(1-->5)-beta-l-Araf-(1--> as well as a small number of longer arabinogalactan side chains. In contrast to crude pollen extracts, the immunological properties of the arabinogalactan mixture reveal an IgG4 reactivity instead of IgE reactivity. Structural properties of timothy pollen arabinogalactan might thus influence the immune response.

Ultrafast Vibrational Energy Relaxation of the Water Bridge

Physical Chemistry Chemical Physics : PCCP. May, 2012  |  Pubmed ID: 21997703

We report the energy relaxation of the OH stretch vibration of HDO molecules contained in an HDO:D(2)O water bridge using femtosecond mid-infrared pump-probe spectroscopy. We found that the vibrational lifetime is shorter (~630 ± 50 fs) than for HDO molecules in bulk HDO:D(2)O (~740 ± 40 fs). In contrast, the thermalization dynamics following the vibrational relaxation are much slower (~1.5 ± 0.4 ps) than in bulk HDO:D(2)O (~250 ± 90 fs). These differences in energy relaxation dynamics strongly indicate that the water bridge and bulk water differ on a molecular scale.

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