The Flagellar Transcriptional Regulator FtcR Controls Brucella melitensis 16M Biofilm Formation via a betI-Mediated Pathway in Response to Hyperosmotic Stress

The expression of flagellar proteins in Brucella species likely evolved through genetic transference from other microorganisms, and contributed to virulence, adaptability, and biofilm formation. Despite significant progress in defining the molecular mechanisms behind flagellar gene expression, the genetic program controlling biofilm formation remains unclear. The flagellar transcriptional factor (FtcR) is a master regulator of the flagellar system’s expression, and is critical for B. melitensis 16M’s flagellar biogenesis and virulence. Here, we demonstrate that FtcR mediates biofilm formation under hyperosmotic stress. Chromatin immunoprecipitation with next-generation sequencing for FtcR and RNA sequencing of ftcR-mutant and wild-type strains revealed a core set of FtcR target genes. We identified a novel FtcR-binding site in the promoter region of the osmotic-stress-response regulator gene betI, which is important for the survival of B. melitensis 16M under hyperosmotic stress. Strikingly, this site autoregulates its expression to benefit biofilm bacteria’s survival under hyperosmotic stress. Moreover, biofilm reduction in ftcR mutants is independent of the flagellar target gene fliF. Collectively, our study provides new insights into the extent and functionality of flagellar-related transcriptional networks in biofilm formation, and presents phenotypic and evolutionary adaptations that alter the regulation of B. melitensis 16M to confer increased tolerance to hyperosmotic stress

Molecular Detection of Zoonotic and Veterinary Pathogenic Bacteria in Pet Dogs and Their Parasitizing Ticks in Junggar Basin, North-Western China

Despite the recognized epidemiological importance of ticks as vectors for pathogens that cause numerous zoonotic and veterinary diseases, data regarding the pathogens of pet dogs and their parasitic ticks in the Junggar Basin are scarce. In this study, a total of 178 blood samples and 436 parasitic ticks were collected from pet dogs in Junggar Basin, Xinjiang Uygur Autonomous Region (XUAR), north-western China. All ticks were identified as Rhipicephalus turanicus sensu stricto (s.s.) according to morphological and molecular characteristics. Rh. turanicus s.s. ticks were collected from pet dogs in China for the first time. Seven tick-borne pathogens, such as Ehrlichia chaffeensis, Anaplasma phagocytophilum, Rickettsia massiliae, Candidatus R. barbariae, Brucella spp., Rickettsia sibirica, and Anaplasma ovis, were detected from ticks, whereas the first five bacteria were detected from blood samples of dogs. Brucella spp. was the most predominant pathogen in both blood samples and ticks of pet dogs, with the detection rates of 16.29 and 16.74%, respectively. Moreover, 17 ticks and 1 blood sample were co-infected with two pathogens, and 1 tick was co-infected with three pathogens. This study provided molecular evidence for the occurrence of Anaplasma spp., Ehrlichia spp., Rickettsia spp., and Brucella spp. circulating in pet dogs and their parasitic ticks in Junggar Basin, north-western China. These findings extend our knowledge of the tick-borne pathogens in pet dogs and their parasitic ticks in Central Asia; therefore, further research on these pathogens and their role in human and animal diseases is required

Measurement of the mass difference and relative production rate of the Ωb−\Omega^-_b and Ξb−\Xi^-_b baryons

The mass difference between the $\Omega^-_b$ and $\Xi^-_b$ baryons is measured using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of $9 \, \text{fb}^{-1}$, and is found to be \begin{equation} m(\Omega^-_b)- m(\Xi^-_b) = 248.54 \pm 0.51 \text{(stat)} \pm 0.38 \text{(syst)} \, \text{MeV}/c^2. \end{equation} The mass of the $\Omega^-_b$ baryon is measured to be \begin{equation} m(\Omega^-_b)= 6045.9 \pm 0.5 \text{(stat)} \pm 0.6 \text{(syst)} \, \text{MeV}/c^2. \end{equation} This is the most precise determination of the $\Omega^-_b$ mass to date. In addition, the production rate of $\Omega^-_b$ baryons relative to that of $\Xi^-_b$ baryons is measured for the first time in $pp$ collisions, using an LHCb dataset collected at a center-of-mass energy of $13 \, \text{TeV}$ and corresponding to an integrated luminosity of $6\,\text{fb}^{-1}$. Reconstructing beauty baryons in the kinematic region $2 < \eta < 6$ and $p_T < 20\,\text{GeV}/c$ with their decays to a $J/\psi$ meson and a hyperon, the ratio \begin{equation} \frac{f_{\Omega^-_b}}{f_{\Xi^-_b}}\times\frac{\mathcal{B}(\Omega^-_b \to J/\psi \Omega^-)}{\mathcal{B}(\Xi^-_b \to J/\psi \Xi^-)} = 0.120 \pm 0.008 \text{(stat)} \pm 0.008 \text{(syst)}, \end{equation} is obtained, where $f_{\Omega^-_b}$ and $f_{\Xi^-_b}$ are the fragmentation fractions of $b$ quarks into $\Omega^-_b$ and $\Xi^-_b$ baryons, respectively, and $\mathcal{B}$ represents the branching fractions of their respective decays.Comment: 23 pages, 3 figures. All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-053.html (LHCb public pages

First Observation of a Doubly Charged Tetraquark and Its Neutral Partner

A combined amplitude analysis is performed for the decays B0→D ̄D0s+π- and B+→D-Ds+π+, which are related by isospin symmetry. The analysis is based on data collected by the LHCb detector in proton-proton collisions at center-of-mass energies of 7, 8, and 13 TeV. The full data sample corresponds to an integrated luminosity of 9 fb-1. Two new resonant states with masses of 2.908±0.011±0.020 GeV and widths of 0.136±0.023±0.013 GeV are observed, which decay to Ds+π+ and Ds+π- respectively. The former state indicates the first observation of a doubly charged open-charm tetraquark state with minimal quark content [cs ̄ud ̄], and the latter state is a neutral tetraquark composed of [cs ̄ūd] quarks. Both states are found to have spin-parity of 0+, and their resonant parameters are consistent with each other, which suggests that they belong to an isospin triplet

Search for D∗(2007)0→μ+μ− in B−→π−μ+μ− decays

The very rare D*(2007)(0) -&gt; mu(+)mu(-) decay is searched for by analysing B- -&gt; pi(-)mu(+)mu(-) decays. The analysis uses a sample of beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb(-1). The signal signature corresponds to simultaneous peaks in the mu(+)mu(-) and pi(-)mu(+)mu(-) invariant masses. No evidence for an excess of events over background is observed and an upper limit is set on the branching fraction of the decay at B(D*(2007)(0) -&gt; mu(+)mu(-)) &lt; 2.6x10(-8) at 90% confidence level. This is the first limit on the branching fraction of D*(2007)(0) -&gt; mu(+)mu(-) decays and the most stringent limit on D*(2007)(0) decays to leptonic final states. The analysis is the first search for a rare charm-meson decay exploiting production via beauty decays

Measurement of Υ production in pp collisions at s√ = 5 TeV

The production cross-sections of Υ mesons, namely Υ(1S), Υ(2S) and Υ(3S), in pp collisions at s√ = 5 TeV are measured with a data sample corresponding to an integrated luminosity of 9.13 ± 0.18 pb−1 collected by the LHCb detector. The Υ mesons are reconstructed in the decay mode Υ → μ+μ−. Double differential cross-sections times branching fractions, as functions of the transverse momentum pT and the rapidity y of the Υ mesons, are measured in the range pT &lt; 20 GeV/c and 2.0 &lt; y &lt; 4.5. The results integrated over these pT and y ranges are σ(Y(1S))×B(Y(1S)→μ+μ−)=2101±33±83 pb, σ(Y(2S))×B(Y(2S)→μ+μ−)=526±20±21 pb, σ(Y(3S))×B(Y(3S)→μ+μ−)=242±16±10 pb, where the first uncertainties are statistical and the second are systematic. The ratios of cross-sections between measurements of two different Υ states and between measurements at different centre-of-mass energies are determined. The nuclear modification factor of Υ(1S) at s√ = 5 TeV is updated as well using the directly measured cross-section results from this analysis

Search for the doubly heavy baryon Ξbc+\it{\Xi}_{bc}^{+} decaying to J/ψΞc+J/\it{\psi} \it{\Xi}_{c}^{+}

A first search for the $\it{\Xi}_{bc}^{+}\to J/\it{\psi}\it{\Xi}_{c}^{+}$ decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of $9\,\mathrm{fb}^{-1}$ recorded at centre-of-mass energies of 7, 8, and $13\mathrm{\,Te\kern -0.1em V}$. Two peaking structures are seen with a local (global) significance of $4.3\,(2.8)$ and $4.1\,(2.4)$ standard deviations at masses of $6571\,\mathrm{Me\kern -0.1em V\!/}c^2$ and $6694\,\mathrm{Me\kern -0.1em V\!/}c^2$, respectively. Upper limits are set on the $\it{\Xi}_{bc}^{+}$ baryon production cross-section times the branching fraction relative to that of the $B_{c}^{+}\to J/\it{\psi} D_{s}^{+}$ decay at centre-of-mass energies of 8 and $13\mathrm{\,Te\kern -0.1em V}$, in the $\it{\Xi}_{bc}^{+}$ and in the $B_{c}^{+}$ rapidity and transverse-momentum ranges from 2.0 to 4.5 and 0 to $20\,\mathrm{Ge\kern -0.1em V\!/}c$, respectively. Upper limits are presented as a function of the $\it{\Xi}_{bc}^{+}$ mass and lifetime.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-005.html (LHCb public pages

First observation and branching fraction measurement of the Λb0→Ds−p\Lambda_b^0\to D_s^- p decay

The first observation of the $\Lambda_b^0\to D_s^- p$ decay is presented using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of ${\sqrt{s}=13 \,\textrm{TeV}}$, corresponding to a total integrated luminosity of $6\,\textrm{fb}^{-1}$. Using the $\Lambda_b^0\to\Lambda_c^+\pi^-$ decay as the normalisation mode, the branching fraction of the $\Lambda_b^0\to D_s^- p$ decay is measured to be ${\mathcal{B}(\Lambda_b^0\to D_s^- p)=(12.6 \pm 0.5 \pm 0.3 \pm 1.2 )\times 10^{-6}}$, where the first uncertainty is statistical, the second systematic and the third due to uncertainties in the branching fractions of the $\Lambda_b^0\to\Lambda_c^+\pi^-$, $D_s^- \to K^-K^+\pi^-$ and $\Lambda_c^+\to p K^- \pi^+$ decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-038.html (LHCb public pages

Observation of a resonant structure near the Ds+Ds−D_s^+ D_s^- threshold in the B+→Ds+Ds−K+B^+\to D_s^+ D_s^- K^+ decay

An amplitude analysis of the $B^+\to D_s^+ D_s^- K^+$ decay is carried out to study for the first time its intermediate resonant contributions, using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV. A near-threshold peaking structure, referred to as $X(3960)$, is observed in the $D_s^+ D_s^-$ invariant-mass spectrum with significance greater than 12 standard deviations. The mass, width and the quantum numbers of the structure are measured to be $3956\pm5\pm10$ MeV, $43\pm13\pm8$ MeV and $J^{PC}=0^{++}$, respectively, where the first uncertainties are statistical and the second systematic. The properties of the new structure are consistent with recent theoretical predictions for a state composed of $c\bar{c}s\bar{s}$ quarks. Evidence for an additional structure is found around 4140 MeV in the $D_s^+ D_s^-$ invariant mass, which might be caused either by a new resonance with the $0^{++}$ assignment or by a $J/\psi \phi\leftrightarrow D_s^+ D_s^-$ coupled-channel effect.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-018.html (LHCb public pages

Occupying Cave-Sites: A Case Study from Azokh 1 Cave (Southern Caucasus)

peer reviewedThe Caucasus is an important intercontinental passageway for fauna and hominin dispersal from Africa to Eurasia. Numerous Pleistocene sites emphasise the importance of this region for the study of human evolution and hominin ‘Out of Africa’ dispersals. The Azokh 1 site in the Southern Caucasus provides a stratigraphic sequence, the renewed excavations of which have shown the presence of well-contextualised lithic and faunal assemblages dated between 300 and 100 ka associated with hominin remains (Homo heidelbergensis and Homo neanderthalensis) also found in the site. Faunal assemblages are dominated by cave bear (Ursus spelaeus) remains resulting from their hibernation at the rear of the cave. Recent taphonomic studies indicate the in-situ exploitation of some of these remains. Other faunal remains, mainly herbivore, some showing signs of human activity, were most likely introduced into the cave by hominins. The study of lithic artefacts suggests an incomplete operative chain for all raw materials with a general absence of knapping debris, unknapped cobbles/pebbles, rare cores and refits. Techno-typologically, these assemblages display characteristics that link them to Late Acheulean or Early Mousterian and Levallois Mousterian traditions. The faunal and lithic assemblages originate from the rear of the cave. Research results, including some preliminary data on lithic use-wear, along with analyses of spatial distribution and post-depositional modification, indicate that occupation of the cave was short and seasonal in character. Cave bears were an important factor affecting the duration of hominin occupation of the cave. The characteristics of the lithic assemblages suggest mobile toolkits, with some isolated evidence of in situ knapping and retouching activities