Tenth-Order QED Contribution to the Electron g-2 and an Improved Value of the Fine Structure Constant

This paper presents the complete QED contribution to the electron g-2 up to the tenth order. With the help of the automatic code generator, we have evaluated all 12672 diagrams of the tenth-order diagrams and obtained 9.16 (58)(\alpha/\pi)^5. We have also improved the eighth-order contribution obtaining -1.9097(20)(\alpha/\pi)^4, which includes the mass-dependent contributions. These results lead to a_e(theory)=1 159 652 181.78 (77) \times 10^{-12}. The improved value of the fine-structure constant \alpha^{-1} = 137.035 999 174 (35) [0.25 ppb] is also derived from the theory and measurement of a_e.Comment: 4 pages, 2 figures. Some numbers are slightly change

Thermostable lipases from the extreme thermophilic anaerobic bacteria Thermoanaerobacter thermohydrosulfuricus SOL1 and Caldanaerobacter subterraneus subsp. tengcongensis

Two novel genes encoding for heat and solvent stable lipases from strictly anaerobic extreme thermophilic bacteria Thermoanaerobacter thermohydrosulfuricus (LipTth) and Caldanaerobacter subterraneus subsp. tengcongensis (LipCst) were successfully cloned and expressed in E. coli. Recombinant proteins were purified to homogeneity by heat precipitation, hydrophobic interaction, and gel filtration chromatography. Unlike the enzymes from mesophile counterparts, enzymatic activity was measured at a broad temperature and pH range, between 40 and 90°C and between pH 6.5 and 10; the half-life of the enzymes at 75°C and pH 8.0 was 48 h. Inhibition was observed with 4-(2-aminoethyl)-benzenesulfonyl fluoride hydrochloride and phenylmethylsulfonylfluorid indicating that serine and thiol groups play a role in the active site of the enzymes. Gene sequence comparisons indicated very low identity to already described lipases from mesophilic and psychrophilic microorganisms. By optimal cultivation of E. coli Tuner (DE3) cells in 2-l bioreactors, a massive production of the recombinant lipases was achieved (53–2200 U/l) Unlike known lipases, the purified robust proteins are resistant against a large number of organic solvents (up to 99%) and detergents, and show activity toward a broad range of substrates, including triacylglycerols, monoacylglycerols, esters of secondary alcohols, and p-nitrophenyl esters. Furthermore, the enzyme from T. thermohydrosulfuricus is suitable for the production of optically pure compounds since it is highly S-stereoselective toward esters of secondary alcohols. The observed E values for but-3-yn-2-ol butyrate and but-3-yn-2-ol acetate of 21 and 16, respectively, make these enzymes ideal candidates for kinetic resolution of synthetically useful compounds

Sensing and Integration of Erk and PI3K Signals by Myc

The transcription factor Myc plays a central role in regulating cell-fate decisions, including proliferation, growth, and apoptosis. To maintain a normal cell physiology, it is critical that the control of Myc dynamics is precisely orchestrated. Recent studies suggest that such control of Myc can be achieved at the post-translational level via protein stability modulation. Myc is regulated by two Ras effector pathways: the extracellular signal-regulated kinase (Erk) and phosphatidylinositol 3-kinase (PI3K) pathways. To gain quantitative insight into Myc dynamics, we have developed a mathematical model to analyze post-translational regulation of Myc via sequential phosphorylation by Erk and PI3K. Our results suggest that Myc integrates Erk and PI3K signals to result in various cellular responses by differential stability control of Myc protein isoforms. Such signal integration confers a flexible dynamic range for the system output, governed by stability change. In addition, signal integration may require saturation of the input signals, leading to sensitive signal integration to the temporal features of the input signals, insensitive response to their amplitudes, and resistance to input fluctuations. We further propose that these characteristics of the protein stability control module in Myc may be commonly utilized in various cell types and classes of proteins

Even-electron ions: A systematic study of the neutral species lost in the dissociation of quasi-molecular ions

The collision-induced dissociations of the even-electron [M + H](+) and/or [M - H](-) ions of 121 model compounds (mainly small aromatic compounds with one to three functional groups) ionized by electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) have been studied using an ion trap, instrument, and the results are compared with the literature data. While some functional groups (such as COOH, COOCH3, SO3H in the negative ion mode, or NO2 in both the positive and negative ion modes) generally promote the loss of neutrals that are characteristic as well as specific, other functional groups (such as COOH in the positive ion mode) give rise to the loss of neutrals that are characteristic, but not specific. Finally, functional groups such as OH and NH2 in aromatic compounds do not lead to the loss of a neutral that reflects the presence of these substituents. In general, the dissociation of [M + H](+) and [M - H](-) ions generated from aliphatic compounds or compounds containing an aliphatic moiety obeys the even-electron rule (loss of a molecule), but deviations from this rule (loss of a radical) are sometimes observed for aromatic compounds, in particular for nitroaromatic compounds. Thermochemical data and ab initio calculations at the CBS-QB3 level of theory provide an explanation for these exceptions. When comparing the dissociation behaviour of the even-electron [M + H](+) and/or [M - H](-) ions (generated by ESI or APCI) with that of the corresponding odd-electron [M](+) ions (generated by electron ionization, EI), three cases may be distinguished: (1) the dissociation of the two ionic species differs completely; (2) the dissociation involves the loss of a common neutral, yielding product ions differing in mass by one Da, or (3) the dissociations lead to a common production

Isolation and Biochemical Characterization of Two Novel Metagenome-derived Estarases

The metagenomes of uncultured microbial communities are rich sources for novel biocatalysts. In this study, esterase EstA3 was derived from a drinking water metagenome, and esterase EstCE1 was derived from a soil metagenome. Both esterases are approximately 380 amino acids in size and show similarity to beta-lactamases, indicating that they belong to family VIII of the lipases/esterases. EstA3 had a temperature optimum at 50 degrees C and a pH optimum at pH 9.0. It was remarkably active and very stable in the presence of solvents and over a wide temperature and pH range. It is active in a multimeric form and displayed a high level of activity against a wide range of substrates including one secondary ester, 7-[3-octyicarboxy(3-hydroxy-3-methyl-butyloxy)]-coumarin, which is normally unreactive. EstCE1 was active in the monomeric form and had a temperature optimum at 47 degrees C and a pH optimum at pH 10. It exhibited the same level of stability as EstA3 over wide temperature and pH ranges and in the presence of dimethyl sulfoxide, isopropanol, and methanol. EstCE1 was highly enantioselective for (+)-menthylacetate. These enzymes display remarkable characteristics that cannot be related to the original environment from which they were derived. The high level of stability of these enzymes together with their unique substrate specificities make them highly useful for biotechnological applications

Isolation and Biochemical Characterization of Two Novel Metagenome-Derived Esterases

The metagenomes of uncultured microbial communities are rich sources for novel biocatalysts. In this study, esterase EstA3 was derived from a drinking water metagenome, and esterase EstCE1 was derived from a soil metagenome. Both esterases are approximately 380 amino acids in size and show similarity to β-lactamases, indicating that they belong to family VIII of the lipases/esterases. EstA3 had a temperature optimum at 50°C and a pH optimum at pH 9.0. It was remarkably active and very stable in the presence of solvents and over a wide temperature and pH range. It is active in a multimeric form and displayed a high level of activity against a wide range of substrates including one secondary ester, 7-[3-octylcarboxy-(3-hydroxy-3-methyl-butyloxy)]-coumarin, which is normally unreactive. EstCE1 was active in the monomeric form and had a temperature optimum at 47°C and a pH optimum at pH 10. It exhibited the same level of stability as EstA3 over wide temperature and pH ranges and in the presence of dimethyl sulfoxide, isopropanol, and methanol. EstCE1 was highly enantioselective for (+)-menthylacetate. These enzymes display remarkable characteristics that cannot be related to the original environment from which they were derived. The high level of stability of these enzymes together with their unique substrate specificities make them highly useful for biotechnological applications