Deletion of BmoR affects the expression of genes related to thiol/disulfide balance in Bacteroides fragilis

Bacteroides fragilis, an opportunistic pathogen and commensal bacterium in the gut, is one the most aerotolerant species among strict anaerobes. However, the mechanisms that control gene regulation in response to oxidative stress are not completely understood. In this study, we show that the MarR type regulator, BmoR, regulates the expression of genes involved in the homeostasis of intracellular redox state. Transcriptome analysis showed that absence of BmoR leads to altered expression in total of 167 genes. Sixteen of these genes had a 2-fold or greater change in their expression. Most of these genes are related to LPS biosynthesis and carbohydrates metabolism, but there was a signifcant increase in the expression of genes related to the redox balance inside the cell. A pyridine nucleotide-disulfde oxidoreductase located directly upstream of bmoR was shown to be repressed by direct binding of BmoR to the promoter region. The expression of two other genes, coding for a thiosulphate:quinoneoxidoreductase and a thioredoxin, are indirectly afected by bmoR mutation during oxygen exposure. Phenotypic assays showed that BmoR is important to maintain the thiol/disulfde balance in the cell, confrming its relevance to B. fragilis response to oxidative stress

Measurement of the Relative Branching Fraction of Υ(4S)\Upsilon(4S) to Charged and Neutral B-Meson Pairs

We analyze 9.7 x 10^6 B\bar{B}$ pairs recorded with the CLEO detector to determine the production ratio of charged to neutral B-meson pairs produced at the Y(4S) resonance. We measure the rates for B^0 -> J/psi K^{(*)0} and B^+ -> J/psi K^{(*)+} decays and use the world-average B-meson lifetime ratio to extract the relative widths f+-/f00 = Gamma(Y(4S) -> B+B-)/Gamma(Y(4S) -> B0\bar{B0}) = = 1.04 +/- 0.07(stat) +/- 0.04(syst). With the assumption that f+- + f00 = 1, we obtain f00 = 0.49 +/- 0.02(stat) +/- 0.01(syst) and f+- = 0.51 +/- 0.02(stat) +/- 0.01(syst). This production ratio and its uncertainty apply to all exclusive B-meson branching fractions measured at the Y(4S) resonance.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

First Observation of the Decays B0→D∗−ppˉπ+B^{0}\to D^{*-}p\bar{p}\pi^{+} and B^{0}\to D^{*-}p\bar{n}$

We report the first observation of exclusive decays of the type B to D^* N anti-N X, where N is a nucleon. Using a sample of 9.7 times 10^{6} B-Bbar pairs collected with the CLEO detector operating at the Cornell Electron Storage Ring, we measure the branching fractions B(B^0 \to D^{*-} proton antiproton \pi^+) = ({6.5}^{+1.3}_{-1.2} +- 1.0) \times 10^{-4} and B(B^0 \to D^{*-} proton antineutron) = ({14.5}^{+3.4}_{-3.0} +- 2.7) times 10^{-4}. Antineutrons are identified by their annihilation in the CsI electromagnetic calorimeter.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Study of the Decays B0 --> D(*)+D(*)-

The decays B0 --> D*+D*-, B0 --> D*+D- and B0 --> D+D- are studied in 9.7 million Y(4S) --> BBbar decays accumulated with the CLEO detector. We determine Br(B0 --> D*+D*-) = (9.9+4.2-3.3+-1.2)e-4 and limit Br(B0 --> D*+D-) < 6.3e-4 and Br(B0 --> D+D-) < 9.4e-4 at 90% confidence level (CL). We also perform the first angular analysis of the B0 --> D*+D*- decay and determine that the CP-even fraction of the final state is greater than 0.11 at 90% CL. Future measurements of the time dependence of these decays may be useful for the investigation of CP violation in neutral B meson decays.Comment: 21 pages, 5 figures, submitted to Phys. Rev.

A Search for B→τνB\to \tau\nu

We report results of a search for $B\to\tau\nu$ in a sample of 9.7 million charged $B$ meson decays. The search uses both $\pi\nu$ and $\ell\nu\bar\nu$ decay modes of the $\tau$, and demands exclusive reconstruction of the companion $\bar B$ decay to suppress background. We set an upper limit on the branching fraction ${\cal B}(B\to \tau\nu) < 8.4\times 10^{-4}$ at 90% confidence level. With slight modification to the analysis we also establish ${\cal B}(B^\pm\to K^\pm\nu\bar\nu) < 2.4\times 10^{-4}$ at 90% confidence level.Comment: 10 ages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Measurements of B --> D_s^{(*)+} D^{*(*)} Branching Fractions

This article describes improved measurements by CLEO of the $B^0 \to D_s^+ D^{*-}$ and $B^0 \to D_s^{*+} D^{*-}$ branching fractions, and first evidence for the decay $B^+ \to D_s^{(*)+} \bar{D}^{**0}$, where $\bar{D}^{**0}$ represents the sum of the $\bar{D}_1(2420)^0$, $\bar{D}_2^*(2460)^0$, and $\bar{D}_1(j=1/2)^0$ L=1 charm meson states. Also reported is the first measurement of the $D_s^{*+}$ polarization in the decay $B^0 \to D_s^{*+} D^{*-}$. A partial reconstruction technique, employing only the fully reconstructed $D_s^+$ and slow pion $\pi_s^-$ from the $D^{*-} \to \bar{D}^0 \pi^-_s$ decay, enhances sensitivity. The observed branching fractions are ${\mathcal B} (B^0 \to D_s^+ D^{*-}) = (1.10 \pm 0.18 \pm 0.10 \pm 0.28)$, ${\mathcal B} (B^0 \to D_s^{*+} D^{*-}) = (1.82 \pm 0.37 \pm 0.24 \pm 0.46)$, and ${\mathcal B} (B^+ \to D_s^{(*)+} \bar{D}^{**0}) = (2.73 \pm 0.78 \pm 0.48 \pm 0.68)$, where the first error is statistical, the second systematic, and the third is due to the uncertainty in the $D_s^+ \to \phi \pi^+$ branching fraction. The measured $D_s^{*+}$ longitudinal polarization, $\Gamma_L/\Gamma = (50.6 \pm 13.9 \pm 3.6)$, is consistent with the factorization prediction of 54%.Comment: 26 pages (LaTeX), 15 figures. To be submitted to PR

Improved Measurement of the Pseudoscalar Decay Constant fDsf_{D_{s}}

We present a new determination of the Ds decay constant, f_{Ds} using 5 million continuum charm events obtained with the CLEO II detector. Our value is derived from our new measured ratio of widths for Ds -> mu nu/Ds -> phi pi of 0.173+/- 0.021 +/- 0.031. Taking the branching ratio for Ds -> phi pi as (3.6 +/- 0.9)% from the PDG, we extract f_{Ds} = (280 +/- 17 +/- 25 +/- 34){MeV}. We compare this result with various model calculations.Comment: 23 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

Precise Measurement of B^{0}\to \bar{B^{0} Mixing Parameters at the Υ(\Upsilon(S)$

We describe a measurement of B^0-B^0bar mixing parameters exploiting a method of partial reconstruction of the decay chains B0 -> D^{*-}\pi^+ and B0 -> D^{*-}\rho^+. Using 9.6 x 10^6 BBbar pairs collected at the Cornell Electron Storage Ring, we find \chi_d = 0.198 +- 0.013 +- 0.014, |y_d|<0.41 at 95% confidence level, and |Re(\epsilon_B)|<0.034 at 95% confidence level.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

First Observation of τ→3πηντ\tau\to 3\pi\eta\nu_{\tau} and τ→f1πντ\tau\to f_{1}\pi\nu_{\tau} Decays

We have observed new channels for $\tau$ decays with an $\eta$ in the final state. We study 3-prong tau decays, using the $\eta\to\gamma\gamma$ and \eta\to 3\piz decay modes and 1-prong decays with two \piz's using the $\eta\to\gamma\gamma$ channel. The measured branching fractions are \B(\tau^{-}\to \pi^{-}\pi^{-}\pi^{+}\eta\nu_{\tau}) =(3.4^{+0.6}_{-0.5}\pm0.6)\times10^{-4} and \B(\tau^{-}\to \pi^{-}2\piz\eta\nu_{\tau} =(1.4\pm0.6\pm0.3)\times10^{-4}. We observe clear evidence for $f_1\to\eta\pi\pi$ substructure and measure \B(\tau^{-}\to f_1\pi^{-}\nu_{\tau})=(5.8^{+1.4}_{-1.3}\pm1.8)\times10^{-4}. We have also searched for $\eta'(958)$ production and obtain 90% CL upper limits \B(\tau^{-}\to \pi^{-}\eta'\nu_\tau)<7.4\times10^{-5} and \B(\tau^{-}\to \pi^{-}\piz\eta'\nu_\tau)<8.0\times10^{-5}.Comment: 11 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

Search for the Decays B^0 -> D^{(*)+} D^{(*)-}

Using the CLEO-II data set we have searched for the Cabibbo-suppressed decays B^0 -> D^{(*)+} D^{(*)-}. For the decay B^0 -> D^{*+} D^{*-}, we observe one candidate signal event, with an expected background of 0.022 +/- 0.011 events. This yield corresponds to a branching fraction of Br(B^0 -> D^{*+} D^{*-}) = (5.3^{+7.1}_{-3.7}(stat) +/- 1.0(syst)) x 10^{-4} and an upper limit of Br(B^0 -> D^{*+} D^{*-}) D^{*\pm} D^\mp and B^0 -> D^+ D^-, no significant excess of signal above the expected background level is seen, and we calculate the 90% CL upper limits on the branching fractions to be Br(B^0 -> D^{*\pm} D^\mp) D^+ D^-) < 1.2 x 10^{-3}.Comment: 12 page postscript file also available through http://w4.lns.cornell.edu/public/CLNS, submitted to Physical Review Letter