Constraints on models for the Higgs boson with exotic spin and parity in VH → Vbb final states

We present constraints on models containing non-standard-model values for the spin J and parity P of the Higgs boson H in up to 9.7 fb(-1) of pp collisions at sqrt[s] = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. These are the first studies of Higgs boson J(P) with fermions in the final state. In the ZH → ℓℓbb, WH → ℓνbb, and ZH → ννbb final states, we compare the standard model (SM) Higgs boson prediction, J(P) = 0(+), with two alternative hypotheses, J(P) = 0(-) and J(P) = 2(+). We use a likelihood ratio to quantify the degree to which our data are incompatible with non-SM J(P) predictions for a range of possible production rates. Assuming that the production rate in the signal models considered is equal to the SM prediction, we reject the J(P) = 0(-) and J(P) = 2(+) hypotheses at the 97.6% CL and at the 99.0% CL, respectively. The expected exclusion sensitivity for a J(P) = 0(-) (J(P) = 2(+)) state is at the 99.86% (99.94%) CL. Under the hypothesis that our data are the result of a combination of the SM-like Higgs boson and either a J(P) = 0(-) or a J(P) = 2(+) signal, we exclude a J(P) = 0(-) fraction above 0.80 and a J(P) = 2(+) fraction above 0.67 at the 95% CL. The expected exclusion covers J(P) = 0(-) (J(P) = 2(+)) fractions above 0.54 (0.47).

Precision measurement of the top quark mass in lepton + jets final States

We measure the mass of the top quark in lepton+jets final states using the full sample of pp collision data collected by the D0 experiment in Run II of the Fermilab Tevatron Collider at sqrt[s] = 1.96 TeV, corresponding to 9.7 fb(-1) of integrated luminosity. We use a matrix element technique that calculates the probabilities for each event to result from tt production or background. The overall jet energy scale is constrained in situ by the mass of the W boson. We measure m(t) = 174.98 ± 0.76 GeV. This constitutes the most precise single measurement of the top-quark mass.

Observation of s-channel production of single top quarks at the Tevatron

We report the first observation of single-top-quark production in the s channel through the combination of the CDF and D0 measurements of the cross section in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb(-1) per experiment. The measured cross section is σ(s) = 1.29(-0.24)(+0.26) pb. The probability of observing a statistical fluctuation of the background to a cross section of the observed size or larger is 1.8 × 10(-10), corresponding to a significance of 6.3 standard deviations for the presence of an s-channel contribution to the production of single-top quarks.

Measurement of the W boson production charge asymmetry in pp̄→W+X→eν+X events at √s=1.96 TeV

We present a measurement of the W boson production charge asymmetry in pp̄→W+X→eν+X events at a center of mass energy of 1.96 TeV, using 9.7  fb-1 of integrated luminosity collected with the D0 detector at the Fermilab Tevatron Collider. The neutrino longitudinal momentum is determined by using a neutrino weighting method, and the asymmetry is measured as a function of the W boson rapidity. The measurement extends over wider electron pseudorapidity region than previous results and is the most precise to date, allowing for precise determination of proton parton distribution functions in global fits.

Measurement of the direct CP-violating charge asymmetry in Ds ± → ϕ π ± decays

We present a measurement of the direct CP-violating charge asymmetry in Ds+ → ϕ π(±) decays where the ϕ meson decays to K(+)K(-), using the full Run II data set with an integrated luminosity of 10.4  fb-1 of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. The normalized difference A(CP) in the yield of D(s)(+) and D(s)(-) mesons in these decays is measured by fitting the difference between their reconstructed invariant mass distributions. This results in an asymmetry of A(CP) = [-0.38 ± 0.27]%, which is the most precise measurement of this quantity to date. The result is consistent with the standard model prediction of zero CP asymmetry in this decay.

Measurement of associated production of z bosons with charm quark jets in pp collisions at √s=1.96 TeV

We present the first measurements of the ratios of cross sections σ(pp → Z+c jet)/σ(pp → Z+jet) and σ(pp → Z+c jet)/σ(pp → Z+b jet) for the associated production of a Z boson with at least one charm or bottom quark jet. Jets have transverse momentum ​pT(jet)​>20  GeV and pseudorapidity |​η(jet)​|<2.5. These cross section ratios are measured differentially as a function of jet and Z boson transverse momenta, based on 9.7  fb(-1) of pp collisions collected with the D0 detector at the Fermilab Tevatron Collider at √s=1.96  TeV. The measurements show significant deviations from perturbative QCD calculations and predictions from various event generators.

Cloning of ε-poly-L-lysine (ε-PL) synthetase gene from a newly isolated ε-PL-producing Streptomyces albulus NK660 and its heterologous expression in Streptomyces lividans

ε-Poly-L-lysine (ε-PL), showing a wide range of antimicrobial activity, is now industrially produced as a food additive by a fermentation process. A new strain capable of producing ε-PL was isolated from a soil sample collected from Gutian, Fujian Province, China. Based on its morphological and biochemical features and phylogenetic similarity with 16S rRNA gene, the strain was identified as Streptomyces albulus and named NK660. The yield of ε-PL in 30 l fed-batch fermentation with pH control was 4.2 g l⁻¹ when using glycerol as the carbon source. The structure of ε-PL was determined by nuclear magnetic resonance (NMR) and matrix-assisted laser desorption/ionization–time of flight mass spectrometry (MALDI-TOF MS). Previous studies have shown that the antimicrobial activity of ε-PL is dependent on its molecular size. In this study, the polymerization degree of the ε-PL produced by strain NK660 ranged from 19 to 33 L-lysine monomers, with the main component consisting of 24–30 L-lysine monomers, which implied that the ε-PL might have higher antimicrobial activity. Furthermore, the ε-PL synthetase gene (pls) was cloned from strain NK660 by genome walking. The pls gene with its native promoter was heterologously expressed in Streptomyces lividans ZX7, and the recombinant strain was capable of synthesizing ε-PL. Here, we demonstrated for the first time heterologous expression of the pls gene in S. lividans. The heterologous expression of pls gene in S. lividans will open new avenues for elucidating the molecular mechanisms of ε-PL synthesis.

CHD1L is a novel independent prognostic factor for gastric cancer

BACKGROUND

Chromodomain helicase/ATPase DNA binding protein 1-like gene (CHD1L) is involved in malignancies. However, the role of CHD1L in gastric cancer (GC) has not been elucidated. The aim of this study is to explore the clinical role of CHD1L in GC.

METHODS

The gene and protein expression levels of CHD1L were detected by quantitative real-time PCR and Western blot analysis in fresh samples of GC and paired adjacent noncancerous tissue (n = 34). We evaluated the CHD1L expression by immunohistochemistry in a large number of GC patients (n = 616) and paired adjacent noncancerous tissues from December 1, 2004 to December 1, 2008. The correlations of CHD1L expression with clinicopathological features and clinical outcome were analyzed.

RESULTS

The gene and protein expression levels of CHD1L were higher in fresh samples of GC than in paired adjacent noncancerous tissues as determined by quantitative real-time PCR and Western blot analysis. Immunohistochemical analysis showed that positive expression rates of CHD1L in GC and paired adjacent noncancerous tissues were 58.7 % (361/616) and 7.3 % (45/616), respectively. CHD1L positivity was significantly associated with clinical stage and distant metastasis. GC patients with positive CHD1L expression had shorter overall survival than those with negative CHD1L expression. Multivariate analysis showed that CHD1L was an independent prognostic marker for overall survival [Hazard Ratio (HR) = 5.952, 95 % confidence interval (CI) = 3.194-11.187, P = 0.0043].

CONCLUSION

These results indicated that CHD1L could serve as a prognostic marker for GC.

Engineering of recombinant Escherichia coli cells co-expressing poly-γ-glutamic acid (γ-PGA) synthetase and glutamate racemase for differential yielding of γ-PGA

Poly-γ-glutamic acid (γ-PGA) is a promising environmental-friendly material with outstanding water solubility, biocompatibility and degradability. However, it is tough to determine the relationship between functional synthetic enzyme and the strains' yield or substrate dependency. We cloned γ-PGA synthetase genes pgsBCA and glutamate racemase gene racE from both L-glutamate-dependent γ-PGA-producing Bacillus licheniformis NK-03 and L-glutamate-independent B. amyloliquefaciens LL3 strains. The deduced RacE and PgsA from the two strains shared the identity of 84.5% and 78.53%, while PgsB and PgsC possessed greater similarity with 93.13% and 93.96%. The induced co-expression of pgsBCA and racE showed that the engineered Escherichia coli strains had the capacity of synthesizing γ-PGA, and LL3 derived PgsBCA had higher catalytic activity and enhanced productivity than NK-03 in Luria–Bertani medium containing glucose or L-glutamate. However, the differential effect was weakened when providing sufficient immediateness L-glutamate substrate, that is, the supply of substrate could be served as the ascendance upon γ-PGA production. Furthermore, RacE integration could enhance γ-PGA yield through improving the preferred d-glutamate content. This is the first report about co-expression of pgsBCA and racE from the two Bacillus strains, which will be of great value for the determination of the biosynthetic mechanism of γ-PGA.

[Progress in markerless knockout of chromosome genes in Streptomycetes]

Streptomycetes are Gram-positive bacteria of Actinomycetales. These organisms can produce many economically important secondary metabolites. With the development of molecular biology, gene sequencing technology and synthetic biology, people gained a better understanding of the Streptomyces family. The means to transform genome on the molecular level is also increasing. By simplifying the Streptomyces genome rationally and efficiently, it will improve the yield and quality of the metabolites as well as reduce the consumption of the substrates. Markerless knockout is an important way to carry out genetic modification. Here we describe novel genome modification techniques developed for Streptomyces in recent years with focus on the markerless knockout technologies.

Measurement of direct CP violation parameters in B± → J/ψK± and B± → J/ψπ± decays with 10.4 fb-1 of Tevatron data

We present a measurement of the direct CP-violating charge asymmetry in B(±) mesons decaying to J/ψK(±) and J/ψπ(±) where J/ψ decays to μ(+) μ(-), using the full run II data set of 10.4 fb(-1) of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. A difference in the yield of B(-) and B(+) mesons in these decays is found by fitting to the difference between their reconstructed invariant mass distributions resulting in asymmetries of A(J/ψK) = [0.59 ± 0.37]%, which is the most precise measurement to date, and A(J/ψπ) = [-4.2 ± 4.5]%. Both measurements are consistent with standard model predictions.

Short-cut nitrification in biological aerated filters with modified zeolite and nitrifying sludge

Autotrophic domestication for short-cut nitrification (SCN) and microorganism immobilization was carried out in a lab-scale biological aerated filters (BAFs) system with activated sludge. Zeolite was chosen as fillings and modified to enlarge the specific surface and to remove toxic metal ions. After thirty-day domestication and immobilization, the NH4(+)-N removal capacity increased to 76.51 mg/g dry sludge (DS) and the ratio of NO2(-)-N converted from NH4(+)-N reached to 91.2% finally. The analysis of growth kinetics indicated that free ammonia should be the key factor for SCN. The abundance variation of nitrifiers, measured by qPCR, showed that AOB was enriched successfully and NOB was washed out. The results also showed that modified zeolite should be more beneficial to the specific immobilization of AOB than natural zeolite. The shift in the community structure of AOB during the domestication by DGGE profile was investigated.