Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to detect monoclonal immunoglobulin light chains in serum and urine.

Rationale: Use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) to monitor serum and urine samples for endogenous monoclonal immunoglobulins. MALDI-TOFMS is faster, fully automatable, and provides superior specificity compared to protein gel electrophoresis (PEL).

Methods: Samples were enriched for immunoglobulins in 5 min using Melon Gel™ followed by reduction with dithiothreitol for 15 min to separate immunoglobulin light chains and heavy chains.

Nanocluster size evolution studied by mass spectrometry in room temperature Au25(SR)18 synthesis.

We show that MALDI mass spectrometry, suitable for mixtures, is an indispensable tool in probing the mechanism of nanocluster synthesis enabling positive identification of nanoclusters. The size evolution of the mixture of larger clusters (Au(102), Au(68), Au(38)) to form highly monodisperse Au(25) nanoclusters is demonstrated and probably includes the participation of Au(I) thiolate. The size evolution via structural reconstruction of the larger cores such as 38, approximately 44, 68, and 102 to a Au(25) nanocluster has been discussed.

Urinary beta2-microglobulin is associated with acute renal allograft rejection.

Background: Identifying urinary biomarkers associated with acute rejection (AR) of kidney allografts could improve recipient care by allowing AR to be diagnosed noninvasively and treated earlier. We attempted to identify novel biomarkers associated with AR by analyzing urinary proteins by using matrix-associated laser desorption ionization time-of-flight mass spectroscopy (MALDI-TOF MS).

Methods: Using MALDI-TOF MS, we analyzed urine samples from 30 renal allograft recipients with biopsy-proven AR, 15 allograft recipients without AR, preoperative samples from 29 kidney donors, and 10 subjects with proteinuric native kidney disease.

Posttranslational modifications in the CP43 subunit of photosystem II.

Photosystem II (PSII) catalyzes the light-driven oxidation of water and the reduction of plastoquinone; the oxidation of water occurs at a cluster of four manganese. The PSII CP43 subunit functions in light harvesting, and mutations in the fifth luminal loop (E) of CP43 have established its importance in PSII structure and/or assembly [Kuhn, M. G.

Electron ionization mass spectral fragmentation of deoxynivalenol and related tricothecenes.

Careful analysis of the electron impact (EI) mass spectral data obtained for the trimethylsilyl (TMS) ethers of known trichothecene mycotoxins of the deoxynivalenol group permitted the construction of a database useful for the identification of these mycotoxins directly from a gas chromatography/mass spectrometry (GC/MS) run. Structures of the ions at m/z 103, 117, 147 and 191 were elucidated by high-resolution mass spectrometry (HRMS) and a fragmentation scheme was suggested. The relative abundances of these ions in the mass spectra of the trichothecenes allowed a fast structural diagnosis during analysis of biological matrices.