A survey of genes encoding H2O2-producing GMC oxidoreductases in 10 Polyporales genomes

The genomes of three representative Polyporales (Bjerkandera adusta, Phlebia brevispora and a member of the Ganoderma lucidum complex) recently were sequenced to expand our knowledge on the diversity and distribution of genes involved in degradation of plant polymers in this Basidiomycota order, which includes most wood-rotting fungi. Oxidases, including members of the glucose-methanol-choline (GMC) oxidoreductase superfamily, play a central role in the above degradative process because they generate extracellular H2O2 acting as the ultimate oxidizer in both white-rot and brown-rot decay. The survey was completed by analyzing the GMC genes in the available genomes of seven more species to cover the four Polyporales clades. First, an in silico search for sequences encoding members of the aryl-alcohol oxidase, glucose oxidase, methanol oxidase, pyranose oxidase, cellobiose dehydrogenase and pyranose dehydrogenase families was performed. The curated sequences were subjected to an analysis of their evolutionary relationships, followed by estimation of gene duplication/ reduction history during fungal evolution. Second, the molecular structures of the near one hundred GMC oxidoreductases identified were modeled to gain insight into their structural variation and expected catalytic properties. In contrast to ligninolytic peroxidases, whose genes are present in all white-rot Polyporales genomes and absent from those of brown-rot species, the H2O2-generating oxidases are widely distributed in both fungal types. This indicates that the GMC oxidases provide H2O2 for both ligninolytic peroxidase activity (in white-rot decay) and Fenton attack on cellulose (in brown-rot decay), after the transition between both decay patterns in Polyporales occurred

Focused directed evolution of aryl-alcohol oxidase in Saccharomyces cerevisiae by using chimeric signal peptides

Aryl-alcohol oxidase (AAO) is an extracellular flavoprotein that supplies ligninolytic peroxidases with H2O2 during natural wood decay. With a broad substrate specificity and highly stereoselective reaction mechanism, AAO is an attractive candidate for studies into organic synthesis and synthetic biology, and yet the lack of suitable heterologous expression systems has precluded its engineering by directed evolution. In this study, the native signal sequence of AAO from Pleurotus eryngii was replaced by those of the mating a-factor and the K1 killer toxin, as well as different chimeras of both prepro-leaders in order to drive secretion in Saccharomyces cerevisiae. The secretion of these AAO constructs increased in the following order: preproa-AAO> preaproK-AAO>preKproa-AAO>preproK-AAO. The chimeric preaproK-AAO was subjected to focused-directed evolution with the aid of a dual screening assay based on the Fenton reaction. Random mutagenesis and DNA recombination was concentrated on two protein segments (Meta1]-Val109 and Phe392-Gln566), and an array of improved variants was identified, among which the FX7 mutant (harboring the H91N mutation) showed a dramatic 96-fold improvement in total activity with secretion levels of 2 mg/liter. Analysis of the N-terminal sequence of the FX7 variant confirmed the correct processing of the preaproK hybrid peptide by the KEX2 protease. FX7 showed higher stability in terms of pH and temperature, whereas the pH activity profiles and the kinetic parameters were maintained. The Asn91 lies in the flavin attachment loop motif, and it is a highly conserved residue in all members of the GMC superfamily, except for P. eryngii and P. pulmonarius AAO. The in vitro involution of the enzyme by restoring the consensus ancestor Asn91 promoted AAO expression and stability

Novel roles for GATAe in growth, maintenance and proliferation of cell populations in the Drosophila renal tubule

The GATA family of transcription factors is implicated in numerous developmental and physiological processes in metazoans. In Drosophila melanogaster, five different GATA factor genes (pannier, serpent, grain, GATAd and GATAe) have been reported as essential in the development and identity of multiple tissues, including the midgut, heart and brain. Here, we present a novel role for GATAe in the function and homeostasis of the Drosophila renal (Malpighian) tubule. We demonstrate that reduced levels of GATAe gene expression in tubule principal cells induce uncontrolled cell proliferation, resulting in tumorous growth with associated altered expression of apoptotic and carcinogenic key genes. Furthermore, we uncover the involvement of GATAe in the maintenance of stellate cells and migration of renal and nephritic stem cells into the tubule. Our findings of GATAe as a potential master regulator in the events of growth control and cell survival required for the maintenance of the Drosophila renal tubule could provide new insights into the molecular pathways involved in the formation and maintenance of a functional tissue and kidney disease

Quantum gravity corrections to the Schwarzschild mass

Vacuum spherically symmetric Einstein gravity in $N\ge 4$ dimensions can be cast in a two-dimensional conformal nonlinear sigma model form by first integrating on the $(N-2)$-dimensional (hyper)sphere and then performing a canonical transformation. The conformal sigma model is described by two fields which are related to the Arnowitt-Deser-Misner mass and to the radius of the $(N-2)$-dimensional (hyper)sphere, respectively. By quantizing perturbatively the theory we estimate the quantum corrections to the ADM mass of a black hole.Comment: 18 pages, 8 figures, LaTeX2e, uses epsfig package, accepted for publication in Phys. Rev.

Open strings, 2D gravity and AdS/CFT correspondence

We present a detailed discussion of the duality between dilaton gravity on AdS_2 and open strings. The correspondence between the two theories is established using their symmetries and field theoretical, thermodynamic, and statistical arguments. We use the dual conformal field theory to describe two-dimensional black holes. In particular, all the semiclassical features of the black holes, including the entropy, have a natural interpretation in terms of the dual microscopic conformal dynamics. The previous results are discussed in the general framework of the Anti-de Sitter/Conformal Field Theory dualities.Comment: 22 pages, Typeset using REVTE

Quantum dilaton gravity as a linear dilaton conformal field theory

A model of matter-coupled gravity in two dimensions is quantized. The crucial requirement for performing the quantization is the vanishing of the conformal anomaly, which is achieved by tuning a parameter in the interaction potential. The spectrum of the theory is determined by mapping the model first onto a field theory with a Liouville interaction, then onto a linear dilaton conformal field theory. In absence of matter fields a pure gauge theory with massless ground state is found; otherwise it is possible to minimally couple up to 11 matter scalar fields: in this case the ground state is tachyonic and the matter sector decouples, like the transverse oscillators in the critical bosonic string.Comment: 7 pages, RevTeX4 file. v2: some comments and one reference adde

Impacts of Zika emergence in Latin America on endemic dengue transmission

In 2015 and 2016, Zika virus (ZIKV) swept through dengue virus (DENV) endemic areas of Latin America. These viruses are of the same family, share a vector and may interact competitively or synergistically through human immune responses. We examine dengue incidence from Brazil and Colombia before, during, and after the Zika epidemic. We find evidence that dengue incidence was atypically low in 2017 in both countries. We investigate whether subnational Zika incidence is associated with changes in dengue incidence and find mixed results. Using simulations with multiple assumptions of interactions between DENV and ZIKV, we find cross-protection suppresses incidence of dengue following Zika outbreaks and low periods of dengue incidence are followed by resurgence. Our simulations suggest correlations in DENV and ZIKV reproduction numbers could complicate associations between ZIKV incidence and post-ZIKV DENV incidence and that periods of low dengue incidence are followed by large increases in dengue incidence

A measurement of the tau mass and the first CPT test with tau leptons

We measure the mass of the tau lepton to be 1775.1+-1.6(stat)+-1.0(syst.) MeV using tau pairs from Z0 decays. To test CPT invariance we compare the masses of the positively and negatively charged tau leptons. The relative mass difference is found to be smaller than 3.0 10^-3 at the 90% confidence level.Comment: 10 pages, 4 figures, Submitted to Phys. Letts.

Observation of Orbitally Excited B_s Mesons

We report the first observation of two narrow resonances consistent with states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+, \bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1}) = 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.Comment: Version accepted and published by Phys. Rev. Let

Measurement of the B0 Lifetime and Oscillation Frequency using B0->D*+l-v decays

The lifetime and oscillation frequency of the B0 meson has been measured using B0->D*+l-v decays recorded on the Z0 peak with the OPAL detector at LEP. The D*+ -> D0pi+ decays were reconstructed using an inclusive technique and the production flavour of the B0 mesons was determined using a combination of tags from the rest of the event. The results t_B0 = 1.541 +- 0.028 +- 0.023 ps, Dm_d = 0.497 +- 0.024 +- 0.025 ps-1 were obtained, where in each case the first error is statistical and the second systematic.Comment: 17 pages, 4 figures, submitted to Phys. Lett.