Lysine succinylation is a newly identified protein posttranslational modification pathway present in both prokaryotic and eukaryotic cells. However, succinylation substrates and regulatory enzyme(s) remain largely unknown, hindering the biological study of this modification. Here we report the identification of 2,580 bacterial lysine succinylation sites in 670 proteins and 2,803 lysine acetylation (Kac) sites in 782 proteins, representing the first lysine succinylation dataset and the largest Kac dataset in wild-type E. coli. We quantified dynamic changes of the lysine succinylation and Kac substrates in response to high glucose. Our data showed that high-glucose conditions led to more lysine-succinylated proteins and enhanced the abundance of succinyllysine peptides more significantly than Kac peptides, suggesting that glucose has a more profound effect on succinylation than on acetylation. We further identified CobB, a known Sir2-like bacterial lysine deacetylase, as the first prokaryotic desuccinylation enzyme. The identification of bacterial CobB as a bifunctional enzyme with lysine desuccinylation and deacetylation activities suggests that the eukaryotic Kac-regulatory enzymes may have enzymatic activities on various lysine acylations with very different structures. In addition, it is highly likely that lysine succinylation could have unique and more profound regulatory roles in cellular metabolism relative to lysine acetylation under some physiological conditions. Molecular & Cellular

Abstract. To quantitatively evaluate the effect of carbonaceous aerosols on the south edge of the Tibetan Plateau, aerosol samples were collected weekly from August 2009 to July 2010 at Qomolangma (Mt. Everest) Station for Atmospheric and Environmental Observation and Research (QOMS, 28.36° N, 86.95° E, 4276 m a.s.l.). The average concentrations of organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon were 1.43, 0.25 and 0.77 μg m−3, respectively. The concentration levels of OC and EC at QOMS are comparable to those at high-elevation sites on the southern slopes of the Himalayas (Langtang and Nepal Climate Observatory at Pyramid, or NCO-P), but 3 to 6 times lower than those at Manora Peak, India, and Godavari, Nepal. Sulfate was the most abundant anion species followed by nitrate, accounting for 25 and 12% of total ionic mass, respectively. Ca2+ was the most abundant cation species (annual average of 0.88 μg m−3). The dust loading, represented by Ca2+ concentration, was relatively constant throughout the year. OC, EC and other ionic species (NH4+, K+, NO3− and SO42−) exhibited a pronounced peak in the pre-monsoon period and a minimum in the monsoon season, being similar to the seasonal trends of aerosol composition reported previously from the southern slope of the Himalayas, such as Langtang and NCO-P. The strong correlation of OC and EC in QOMS aerosols with K+ and levoglucosan indicates that they mainly originated from biomass burning. The fire spots observed by MODIS and backward air-mass trajectories further demonstrate that in pre-monsoon season, agricultural and forest fires in northern India and Nepal were most likely sources of carbonaceous aerosol at QOMS. Moreover, the CALIOP observations confirmed that air-pollution plumes crossed the Himalayas during this period. The highly coherent variation of daily aerosol optical depth (500 nm) between QOMS and NCO-P indicates that both slopes of the Himalayas share a common atmospheric environment regime. In addition to large-scale atmospheric circulation, the unique mountain/valley breeze system can also have an important effect on air-pollutant transport.

We study the interplay of interaction, confining potential and effects of finite temperature at the edge of a quantum Hall liquid. Our exact diagonalization calculation indicates that edge reconstruction occurs in the fractional quantum Hall regime for a variety of confining potential, including ones that correspond to a "sharp" edge. Our finite temperature Hartree-Fock calculation for integer quantum Hall edges indicates that reconstruction is suppressed above certain temperature. We discuss the implication of our results on recent edge tunneling and microwave absorption experiments. 73.40.Hm, 71.10.Pm The physics of the quantum Hall edge states is important for a number of reasons. When the system is in a quantum Hall state, the bulk is incompressible and the edge carries the dissipationless current. In addition, the edge states also provide a unique arena to study correlated electrons in one-dimension, where the Fermi liquid theory breaks down. Indeed, the edge electrons have been argued [1] to form the so-called chiral Luttinger liquid (CLL) in this case, with many properties determined solely by the robust bulk topological order of the system, and independent of the details of the edge potential. For example it was predicted [1] that in the tunneling between a Fermi liquid and a quantum Hall edge, the current-voltage relation follows a power-law I ∼ V α , with universal exponents α for simple edges like that of bulk filling ν = 1/3. While such power-law behavior has been observed in experiments indicating non-Fermi liquid behavior [2], detailed studies of the bulk filling factor as well as sample dependence of α have found important differences from the predictions of CLL theory [3][4][5].In the CLL theory [1], one assumes that there is a single boundary separating the incompressible quantum Hall liquid from the electron vacuum, and for simple edges like those of ν = 1 and ν = 1/3, the only low-energy excitations are the shape fluctuations of the boundary, which form a single branch of chiral bosons. On the other hand it is known that for integer quantum Hall edges, the competition between electron-electron Coulomb interaction and edge confining potential can lead to edge reconstruction [6,7], when the edge confining potential is smooth enough. At the reconstructed edge, the electron density oscillates and there are more than one chiral boson modes, which do not propagate in the same direction [7]. Thus edge reconstruction can change the physics at the edge qualitatively.Motivated by the edge tunneling puzzle, as well as a recent microwave absorption measurement in which the presence of artificial edge channels leads to absorption enhancement [8], we examine in this work the possibility of edge reconstruction when the bulk filling is fractional. We find numerical evidence from exact diagonalization studies suggesting that edge reconstruction can occur when the bulk filling is fractional as well, for a variety of edge confining potentials (including those we believe properly describe a sharp cleaved edge)...