Acrolein, a representative carcinogenic aldehyde, that could be ubiquitously generated in biological systems under oxidative stress shows facile reactivity with a nucleophile such as a protein. In this study, to gain a better understanding of the molecular basis of acrolein modification of protein, we characterized the acrolein modification of a model peptide (the oxidized B chain of insulin) by electrospray ionization-liquid chromatography/mass spectrometry method and established a novel acrolein-lysine condensation reaction. In addition, we found that this condensation adduct represented the major antigenic adduct generated in acrolein-modified protein. To identify the modification site and structures of adducts generated in the acrolein-modified insulin B chain, both the acrolein-pretreated and untreated peptides were digested with V8 protease and the resulting peptides were subjected to electrospray ionization-liquid chromatography/mass spectrometry. This technique identified nine peptides, which contained the acrolein adducts at Lys-29 and the N terminus, and revealed that the reaction of the insulin B chain with acrolein gave multiple adducts, including an unknown adduct containing two molecules of acrolein per lysine. To identify this adduct, we incubated N ␣ -acetyllysine with acrolein and isolated a product having the same molecular mass as the unknown acrolein-lysine adduct. On the basis of the chemical and spectroscopic evidence, the adduct was determined to be a novel pyridinium-type lysine adduct, N ⑀ -(3-methylpyridinium)lysine (MP-lysine). The formation of MP-lysine was confirmed by amino acid analysis of proteins treated with acrolein. More notably, this condensation adduct appeared to be an intrinsic epitope of a monoclonal antibody 5F6 that had been raised against acrolein-modified protein.Several lines of evidence indicate that the oxidative modification of protein and the subsequent accumulation of the modified proteins have been found in cells during aging and oxidative stress and in various pathological states including premature diseases, muscular dystrophy, rheumatoid arthritis, and atherosclerosis (1-4). The important agents that give rise to the modification of a protein may be represented by reactive aldehydic intermediates such as ketoaldehydes, 2-alkenals and 4-hydroxy-2-alkenals (3, 5, 6). These reactive aldehydes are considered important mediators of cell damage because of their ability to covalently modify biomolecules, which can disrupt important cellular functions and can cause mutations (5). Furthermore, the adduction of aldehydes to apolipoprotein B in low density lipoproteins has been strongly implicated in the mechanism by which low density lipoproteins is converted to an atherogenic form that is taken up by macrophages, leading to the formation of foam cells (7,8).Acrolein, an unpleasant and troublesome byproduct of overheated organic matter, occurs as a ubiquitous pollutant in the environment, e.g. the incomplete combustion of plastic materials, cigarette smoking, and over...

[1] Nine triaxial borehole accelerometers were installed within 200 m along a 2650-m-deep haulage tunnel in the Mponeng gold mine in South Africa. We analyzed the high sample rate recordings (15 kHz) to determine source parameters of small earthquakes in the mine. To study the source processes, we carried out multiple time window waveform inversions for five larger events (0.8 < M < 1.4) that occurred within 150 m of the stations. From the inversion results we could determine the fault planes for all five events and estimate the range of rupture speed. We can conclude that rupture speeds were faster than 2.5 km/s (65% of the shear wave velocity). The radiation efficiency is written as a function of the rupture speed and becomes greater with increasing rupture speed. This study indicates that radiation efficiencies of small earthquakes in the South African gold mine are almost equal to those of larger natural earthquakes. We also calculated radiated seismic energies and static stress drops of the five events to investigate their apparent stresses. Apparent stresses of the five events were from 1 to 10 MPa and static stress drops were 1 to 20 MPa. We found that the source parameters (rupture speed, apparent stress, radiation efficiency, and static stress drop) did not largely differ from values for larger natural earthquakes. This suggests that the dynamic rupture processes of these small events were similar to those of the larger natural earthquakes.

After the occurrence of the 2011 magnitude 9 Tohoku earthquake, the seismicity in the overriding plate changed. The seismicity appears to form distinct belts. From the spatiotemporal distribution of hypocenters, we can quantify the evolution of seismicity after the 2011 Tohoku earthquake. In some earthquake swarms near Sendai (Nagamachi-Rifu fault), Moriyoshi-zan volcano, Senya fault, and the Yamagata-Fukushima border (Aizu-Kitakata area, west of Azuma volcano), we can observe temporal expansion of the focal area. This temporal expansion is attributed to fluid diffusion. Observed diffusivity would correspond to the permeability of about 10 À15 (m 2 ). We can detect the area from which fluid migrates as a seismic low-velocity area. In the lower crust, we found seismic low-velocity areas, which appear to be elongated along N-S or NE-SW, the strike of the island arc. These seismic low-velocity areas are located not only beneath the volcanic front but also beneath the fore-arc region. Seismic activity in the upper crust tends to be high above these low-velocity areas in the lower crust. Most of the shallow earthquakes after the 2011 Tohoku earthquake are located above the seismic low-velocity areas. We thus suggest fluid pressure changes are responsible for the belts of seismicity.

[1] We estimate stress drops and radiated seismic energies of 20 microearthquakes (0.0 < M W < 1.3) in a South African gold mine to investigate their rupture characteristics and scaling relationships to large earthquakes. We analyze seismograms of borehole accelerometers recorded with high sampling rate (15 kHz) within 200 m of the hypocenters at the depth of 2650 m. The waveform data have very high signal-to-noise ratio and no significant later phases are observed at all stations. Corner frequencies and quality factors of the anelastic attenuation Q are estimated from spectra of velocity seismograms by assuming the omega squared model of Boatwright (1978). We also investigate moment tensors for double couple solutions and volumetric components from the waveform inversion. Static stress drops of the 20 earthquakes calculated from the model of Madariaga (1976) are from 3.2 to 88 MPa and scaled energies (= E R /M o ; the ratio of the radiated energy E R to the seismic moment M o ) are from 4.2 Â 10 À6 to 1.1 Â 10 À4 . We find that both the static stress drops and the scaled energies of the analyzed earthquakes are comparable to those values of larger earthquakes. Our results indicate that the dynamic rupture processes of these microearthquakes are similar to those of larger earthquakes.