Enrichment of low-abundance brain proteins by preparative electrophoresis

Detection of low-copy-number gene products is essential for the development of novel drugs, however, it represents a major drawback of proteomics and simultaneously a scientific challenge. We studied the enrichment of rat brain cytosolic proteins by preparative electrophoresis using the PrepCell apparatus. The electrophoresis was performed in the presence of 0.1% lithium dodecyl sulfate. The proteins eluted from the gel were analyzed by two-dimensional gel electrophoresis and identified by matrix-assisted laser desorption ionization mass specrometry. Lithium dodecyl sulfate was easily exchanged against agents compatible with isoelectric focusing. Low-abundance proteins, which had not been found before, including neuronal-specific and calcium-binding proteins, were detected. In particular, low-molecular-mass proteins, such as hippocalcin, visinin-like proteins, and 14-3-3 proteins were strongly enriched by preparative electrophoresis.     

Expressional pattern of known and predicted signaling proteins in seven human cell lines

Although a variety of signaling systems and signaling proteins have been described, cell specific expression of these structures has not yet been systematically studied. Human amnion, bronchial epithelial, fibroblast, glial, kidney, lymphocyte and mesothelial cells were subjected to two-dimensional-gel electrophoresis followed by analysis of protein spots by MALDI-TOF and subsequent identification by specific software. A series of well-documented signaling proteins showed cell specific expressional patterns. Five hypothetical proteins--hypothetical 37.5 kDa protein, similar to calsyntenin 1, hypothetical armadillo repeat/plakoglobulin ARM-repeat profile containing protein, 11 days embryo cDNA clone 2700084k13, hypothetical protein flj22171--so far predicted from their nucleic acid sequence only, were identified, complementing already reported signaling cascades. An analytical tool for the concomitant determination of a large series of signaling structures by an antibody independent protein-chemical method is provided.     

Psychophysiology and psychoacoustics of music: Perception of complex sound in normal subjects and psychiatric patients

Perception of complex sound is a process carried out in everyday life situations and contributes in the way one perceives reality. Attempting to explain sound perception and how it affects human beings is complicated. Physics of simple sound can be described as a function of frequency, amplitude and phase. Psychology of sound, also termed psychoacoustics, has its own distinct elements of pitch, intensity and tibre. An interconnection exists between physics and psychology of hearing.Music being a complex sound contributes to communication and conveys information with semantic and emotional elements. These elements indicate the involvement of the central nervous system through processes of integration and interpretation together with peripheral auditory processing.Effects of sound and music in human psychology and physiology are complicated. Psychological influences of listening to different types of music are based on the different characteristics of basic musical sounds. Attempting to explain music perception can be simpler if music is broken down to its basic auditory signals. Perception of auditory signals is analyzed by the science of psychoacoustics. Differences in complex sound perception have been found between normal subjects and psychiatric patients and between different types of psychopathologies.     

Identification of Proteins by Matrix-Assisted Laser Desorption Ionization–Mass Spectrometry Following In-Gel Digestion in Low-Salt, Nonvolatile Buffer and Simplified Peptide Recovery

Matrix-assisted laser desorption ionization–mass spectrometry is an efficient analytical method for large-scale identification of proteins separated by two-dimensional polyacrylamide gel electrophoresis. Following in-gel digestion, the salt present in the peptide extracts is usually removed by chromatography prior to analysis. Desalting is a labor-intensive and time-consuming step, limiting the total number of samples that can be processed daily. We improved the daily sample output by performing the in-gel protein digestion in low-salt, nonvolatile buffer and simplifying the recovery of the generated peptides, collecting them in a small volume by sonication. This technique is routinely used for identification of proteins ofHaemophilus influenzaeand human brain. The methodology described facilitates the analytical process and allows the analysis of hundreds of proteins per day. Furthermore, it represents an essential step toward process automation.