A rapid method for profiling bacterial and cellular proteins has been developed using a combination of capillary high-performance liquid chromatography separation followed by (MALDI-MS) matrix-assisted laser desorption/ionization mass spectrometric analysis. In this method, bacteria are sonicated, the cell walls broken, and the water-soluble proteins precipitated for analysis. The proteins are separated by capillary liquid chromatography and detected on-line by a UV absorption detector. The eluents are then collected for off-line analysis by MALDI-MS. Using this method, it is demonstrated that bacteria can be discriminated based upon their protein profiles to the species level with only pmol level detection of proteins. It has also proved to be a fast and accurate means for monitoring the expression of Hsp27 in an insect cell system.

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The growth and oxygen adsorption of Ag on an ordered Al2O3 film, prepared on Mo(110) substrate, have been studied in situ under ultrahigh-vacuum condition using X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and low-energy electron diffraction. The results show that Ag particles/clusters are formed on alumina film at initial coverages, and the binding energy of the Ag 3d5/2 line for Ag clusters is higher than that of bulk Ag, arisen from the size effect. Exposure of Ag clusters to ∼10-7 mbar O2 leads the clusters to spreading over the substrate. It is of importance in many application areas to understand the origin of oxygen-induced metal-cluster changes in morphology and size.