Blueprint for a minimal photoautotrophic cell: conserved and variable genes in Synechococcus elongatus PCC 7942

Background: Simpler biological systems should be easier to understand and to engineer towards pre-defined goals. One way to achieve biological simplicity is through genome minimization. Here we looked for genomic islands in the fresh water cyanobacteria Synechococcus elongatus PCC 7942 (genome size 2.7 Mb) that could be used as targets for deletion. We also looked for conserved genes that might be essential for cell survival.Results: By using a combination of methods we identified 170 xenologs, 136 ORFans and 1401 core genes in the genome of S. elongatus PCC 7942. These represent 6.5%, 5.2% and 53.6% of the annotated genes respectively. We considered that genes in genomic islands could be found if they showed a combination of: a) unusual G+C content; b) unusual phylogenetic similarity; and/or c) a small number of the highly iterated palindrome 1 (HIP1) motif plus an unusual codon usage. The origin of the largest genomic island by horizontal gene transfer (HGT) could be corroborated by lack of coverage among metagenomic sequences from a fresh water microbialite. Evidence is also presented that xenologous genes tend to cluster in operons. Interestingly, most genes coding for proteins with a diguanylate cyclase domain are predicted to be xenologs, suggesting a role for horizontal gene transfer in the evolution of Synechococcus sensory systems.Conclusions: Our estimates of genomic islands in PCC 7942 are larger than those predicted by other published methods like SIGI-HMM. Our results set a guide to non-essential genes in S. elongatus PCC 7942 indicating a path towards the engineering of a model photoautotrophic bacterial cell.Financial support was provided by grants BFU2009-12895-C02-01/BMC (Ministerio de Ciencia e Innovación, Spain), the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement number 212894 and Prometeo/2009/092 (Conselleria d’Educació, Generalitat Valenciana, Spain) to A. Moya. Work in the FdlC laboratory was supported by grants BFU2008-00995/BMC (Spanish Ministry of Education), RD06/0008/1012 (RETICS research network, Instituto de Salud Carlos III, Spanish Ministry of Health) and LSHM-CT- 2005_019023 (European VI Framework Program). Dr. González-Domenech was supported by grant from the University of Granada. LD, thanks to financial support from Facultad de Ciencias, Universidad Nacional Autónoma de México

Observation of the diphoton decay of the Higgs boson and measurement of its properties

Peer reviewe

Precise determination of the mass of the Higgs boson and tests of compatibility of its couplings with the standard model predictions using proton collisions at 7 and 8 TeV

Peer reviewe

Measurement of the Pseudorapidity and Centrality Dependence of the Transverse Energy Density in Pb-Pb Collisions at √sNN=2.76 TeV

The transverse energy (E-T) in Pb-Pb collisions at 2.76 TeV nucleon-nucleon center-of-mass energy (root s(NN)) has been measured over a broad range of pseudorapidity (eta) and collision centrality by using the CMS detector at the LHC. The transverse energy density per unit pseudorapidity (dE(T)/d eta) increases faster with collision energy than the charged particle multiplicity. This implies that the mean energy per particle is increasing with collision energy. At all pseudorapidities, the transverse energy per participating nucleon increases with the centrality of the collision. The ratio of transverse energy per unit pseudorapidity in peripheral to central collisions varies significantly as the pseudorapidity increases from eta = 0 to vertical bar eta vertical bar = 5.0. For the 5% most central collisions, the energy density per unit volume is estimated to be about 14 GeV/fm(3) at a time of 1 fm/c after the collision. This is about 100 times larger than normal nuclear matter density and a factor of 2.6 times higher than the energy density reported at root s(NN) = 200 GeV at the Relativistic Heavy Ion Collider

Measurement of the differential cross section for isolated prompt photon production in pp collisions at 7 TeV

A measurement of the differential cross section for the inclusive production of isolated prompt photons in proton-proton collisions at a center-of-mass energy of 7 TeV is presented. The data sample corresponds to an integrated luminosity of 36 pb(-1) recorded by the CMS detector at the LHC. The measurement covers the pseudorapidity range vertical bar eta vertical bar < 2.5 and the transverse energy range 25 < E-T < 400 GeV, corresponding to the kinematic region 0.007 < x(T) < 0.114. Photon candidates are identified with two complementary methods, one based on photon conversions in the silicon tracker and the other on isolated energy deposits in the electromagnetic calorimeter. The measured cross section is presented as a function of E-T in four pseudorapidity regions. The next-to-leading-order perturbative QCD calculations are consistent with the measured cross section

Measurement of the production cross section ratio σ(χb2(1P))/σ(χb1(1P))in pp collisions at √s=8TeV

A measurement of the production cross section ratio σ(χb2(1P))/σ(χb1(1P))σ(χb2(1P))/σ(χb1(1P)) is presented. The χb1(1P)χb1(1P) and χb2(1P)χb2(1P) bottomonium states, promptly produced in pp collisions at View the MathML sources=8 TeV, are detected by the CMS experiment at the CERN LHC through their radiative decays χb1,2(1P)→ϒ(1S)+γχb1,2(1P)→ϒ(1S)+γ. The emitted photons are measured through their conversion to e+e−e+e− pairs, whose reconstruction allows the two states to be resolved. The ϒ(1S)ϒ(1S) is measured through its decay to two muons. An event sample corresponding to an integrated luminosity of 20.7 fb−120.7 fb−1 is used to measure the cross section ratio in a phase-space region defined by the photon pseudorapidity, |ηγ|<1.0|ηγ|<1.0; the ϒ(1S)ϒ(1S) rapidity, |yϒ|<1.5|yϒ|<1.5; and the ϒ(1S)ϒ(1S) transverse momentum, View the MathML source7<pTϒ<40 GeV. The cross section ratio shows no significant dependence on the ϒ(1S)ϒ(1S) transverse momentum, with a measured average value of View the MathML source0.85±0.07(stat+syst)±0.08(BF), where the first uncertainty is the combination of the experimental statistical and systematic uncertainties and the second is from the uncertainty in the ratio of the χbχb branching fractions

Measurement of the Zγ production cross section in pp collisions at 8 TeV and search for anomalous triple gauge boson couplings

Open Access, Copyright CERN, for the benefit of the CMS Collaboration. Article funded by SCOAP3.Abstract: The cross section for the production of Zγ in proton-proton collisions at 8 TeV is measured based on data collected by the CMS experiment at the LHC corresponding to an integrated luminosity of 19.5 fb−1. Events with an oppositely-charged pair of muons or electrons together with an isolated photon are selected. The differential cross section as a function of the photon transverse momentum is measured inclusively and exclusively, where the exclusive selection applies a veto on central jets. The observed cross sections are compatible with the expectations of next-to-next-to-leading-order quantum chromodynamics. Limits on anomalous triple gauge couplings of ZZγ and Zγγ are set that improve on previous experimental results obtained with the charged lepton decay modes of the Z boson