Morphology and phylogeny of Prorocentrum caipirignum sp. nov. (Dinophyceae), a new tropical toxic benthic dinoflagellate

17 pages, 14 figures, 1 tableA new species of toxic benthic dinoflagellate is described based on laboratory cultures isolated from two locations from Brazil, Rio de Janeiro and Bahia. The morphology was studied with SEM and LM. Cells are elliptical in right thecal view and flat. They are 37–44 μm long and 29–36 μm wide. The right thecal plate has a V shaped indentation where six platelets can be identified. The thecal surface of both thecal plates is smooth and has round or kidney shaped and uniformly distributed pores except in the central area of the cell, and a line of marginal pores. Some cells present an elongated depression on the central area of the apical part of the right thecal plate. Prorocentrum caipirignum is similar to Prorocentrum lima in its morphology, but can be differentiated by the general cell shape, being elliptical while P. lima is ovoid. In the phylogenetic trees based on ITS and LSU rDNA sequences, the P. caipirignum clade appears close to the clades of P. lima and Prorocentrum hoffmannianum. The Brazilian strains of P. caipirignum formed a clade with strains from Cuba, Hainan Island and Malaysia and it is therefore likely that this new species has a broad tropical distribution. Prorocentrum caipirignum is a toxic species that produces okadaic acid and the fast acting toxin prorocentrolide.This research was funded by FAPERJ/Brazil (Edital Primeiros Projetos to S.M.N.) and International Foundation for Science (IFS research grant A/4177-1 to S.M.N.); CNPq Brazil (Edital Universal 2013 to M.M.); FAPESB/Brazil (Project RED006/2012 and Doctoral scholarship Bol 10685/2013); CAPES/Brazil (Doctoral scholarship 9947-14-0/2014), Unidad Asociada de I + D + i Microalgas Nocivas IEO-CSIC to M.C.Q.M; Spanish Ministerio de Economía y Competitividad (Project CICAN to F.R, P.R, J.M.F and S.F).Peer reviewe

Morphology, molecular phylogeny and toxinology of Coolia and Prorocentrum strains isolated from the tropical South Western Atlantic Ocean

16 pages, 7 figures, 3 tablesThe morphology, molecular phylogeny and toxinology of two Coolia and one Prorocentrum dinoflagellate strains from Brazil were characterized. They matched with Coolia malayensis and Coolia tropicalis morphotypes, while the Prorocentrum strain fitted well with the morphology of Prorocentrum emarginatum. Complementary identification by molecular analyses was carried out based on LSU and ITS-5.8S rDNA. Phylogenetic analyses of Coolia strains (D1/D2 region, LSU rDNA), showed that C. malayensis (strain UFBA044) segregated together with sequences of this species from other parts of the world, but diverged earlier in a separate branch to sequences from São Paulo (Brazil) or Caribbean areas. Coolia tropicalis (strain UFBA055) grouped with other sequences of this species, in a subclade with an isolate from Belize, closer to a subgroup including isolates from Thailand, Australia and Hong Kong. Phylogenetic analyses (ITS-5.8S rDNA) of P. emarginatum (strain UFBA033) grouped together with another sequence of this species from China Sea. Diarrhetic shellfish poisoning toxins (OA, DTXs and PTX2) were not detected in P. emarginatum by mass spectrometry analyses. However, hemolytic assays in P. emarginatum and both Coolia strains in this study showed positive resultsThis study was funded by projects FAPESB – RED0006/2012 and CNPq (Productivity Scholarship in Research # 07368/2015-7), which were granted to J.M.C. Nunes; another CNPq grant (# 471303/2013-5) was granted to M. Menezes; the scholarships from CAPES (PhD scholarship # 9947-14-14-0/2014) and FAPESB (PhD scholarship Bol # 10685/2013) were granted to M.C.Q. MendesPeer reviewe

Toxin production, growth kinetics and molecular characterization of Ostreopsis cf. ovata isolated from Todos os Santos Bay, tropical southwestern Atlantic

13 páginas, 6 figuras, 7 tablasThe toxin profile and hemolytic activity of a strain of Ostreopsis cf. ovata (UFBA013) isolated from Todos os Santos Bay (northeastern Brazil) were evaluated under different levels of N and P. Phylogenetic analyses based on ITS rDNA region (ITS1-5.8S-ITS2) placed UFBA013 within the Atlantic/Mediterranean/Pacific clade of O. cf. ovata. Growth experiments were conducted in f/2 medium modified by adding N and P (P: 0–36 μM; N: 0–882 μM). The growth kinetics was adequately described by logistic equations. The best growth (highest Gm) was recorded under levels of N/P = 0/18, 129/5 and 441/36, while one of the lowest Gm was obtained under P-depletion. The maximum and specific maximum growth rates (as vm; cells mL−1 d−1 and μm; d−1) were achieved with N limitation (N/P = 441/36) and P-limitation/depletion (753/5.3 and 441/0) and are the highest values reported in the literature, most similar to isolates from Pacific and Mediterranean areas. The control experiment (N/P = 441/18) also yielded similar values to those from some Mediterranean isolates, but higher than formerly reported for Brazilian isolates. In all conditions assayed, no palytoxin (PLTX) was detected. The ovatoxins (OVTXs) a, b, c, d and e did not show significant differences in cell quota between exponential and stationary phases. A significant relationship was detected between OVTXs concentration and hemolytic activityThis study was supported by FAPESB - RED0006/2012 and CNPq (Productivity Scholarship in Research # 07368/2015-7) granted to J.M.C. Nunes; CNPq (research grant # 471303/2013-5) to M. Menezes; CAPES (PhD scholarship # 9947-14-14-0/2014) and FAPESB (PhD scholarship Bol. # 10685/2013) to M.C.Q. MendesPeer reviewe

Toxin production, growth kinetics and molecular characterization of

The toxin profile and hemolytic activity of a strain of Ostreopsis cf. ovata (UFBA013) isolated from Todos os Santos Bay (northeastern Brazil) were evaluated under different levels of N and P. Phylogenetic analyses based on ITS rDNA region (ITS1-5.8S-ITS2) placed UFBA013 within the Atlantic/Mediterranean/Pacific clade of O. cf. ovata. Growth experiments were conducted in f/2 medium modified by adding N and P (P: 0–36 μM; N: 0–882 μM). The growth kinetics was adequately described by logistic equations. The best growth (highest Gm) was recorded under levels of N/P = 0/18, 129/5 and 441/36, while one of the lowest Gm was obtained under P-depletion. The maximum and specific maximum growth rates (as vm; cells mL−1 d−1 and μm; d−1) were achieved with N limitation (N/P = 441/36) and P-limitation/depletion (753/5.3 and 441/0) and are the highest values reported in the literature, most similar to isolates from Pacific and Mediterranean areas. The control experiment (N/P = 441/18) also yielded similar values to those from some Mediterranean isolates, but higher than formerly reported for Brazilian isolates. In all conditions assayed, no palytoxin (PLTX) was detected. The ovatoxins (OVTXs) a, b, c, d and e did not show significant differences in cell quota between exponential and stationary phases. A significant relationship was detected between OVTXs concentration and hemolytic activity.Versión del edito

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved

Search for CP violating top quark couplings in pp collisions at s \sqrt{s} = 13 TeV

International audienceResults are presented from a search for CP violation in top quark pair production, using proton-proton collisions at a center-of-mass energy of 13 TeV. The data used for this analysis consist of final states with two charged leptons collected by the CMS experiment, and correspond to an integrated luminosity of 35.9 fb$^{−1}$. The search uses two observables, $\mathcal{O} _{1}$ and $\mathcal{O} _{3}$, which are Lorentz scalars. The observable $\mathcal{O} _{1}$ is constructed from the four-momenta of the charged leptons and the reconstructed top quarks, while $\mathcal{O} _{3}$ consists of the four-momenta of the charged leptons and the b quarks originating from the top quarks. Asymmetries in these observables are sensitive to CP violation, and their measurement is used to determine the chromoelectric dipole moment of the top quark. The results are consistent with the expectation from the standard model.[graphic not available: see fulltext

Search for new physics in the lepton plus missing transverse momentum final state in proton-proton collisions at s=\sqrt{s} = 13 TeV

International audienceA search for physics beyond the standard model (SM) in final states with an electron or muon and missing transverse momentum is presented. The analysis uses data from proton-proton collisions at a centre-of-mass energy of 13 TeV, collected with the CMS detector at the LHC in 2016-2018 and corresponding to an integrated luminosity of 138 fb$^{-1}$. No significant deviation from the SM prediction is observed. Model-independent limits are set on the production cross section of W' bosons decaying into lepton-plus-neutrino final states. Within the framework of the sequential standard model, with the combined results from the electron and muon decay channels a W' boson with mass less than 5.7 TeV is excluded at 95% confidence level. Results on a SM precision test, the determination of the oblique electroweak $W$ parameter, are presented using LHC data for the first time. These results together with those from the direct W' resonance search are used to extend existing constraints on composite Higgs scenarios. This is the first experimental exclusion on compositeness parameters using results from LHC data other than Higgs boson measurements

Search for direct pair production of supersymmetric partners of τ\tau leptons in the final state with two hadronically decaying τ\tau leptons and missing transverse momentum in proton-proton collisions at s\sqrt{s} = 13 TeV

A search for the direct production of a pair of $τ$ sleptons, the supersymmetric partners of $τ$ leptons, is presented. Each $τ$ slepton is assumed to decay to a $τ$ lepton and the lightest supersymmetric particle (LSP), which is assumed to be stable and to not interact in the detector, leading to an imbalance in the total reconstructed transverse momentum. The search is carried out in events identified as containing two $τ$ leptons, each decaying to one or more hadrons and a neutrino, and significant transverse momentum imbalance. In addition to scenarios in which the $τ$ sleptons decay promptly, the search also addresses scenarios in which the $τ$ sleptons have sufficiently long lifetimes to give rise to nonprompt $τ$ leptons. The data were collected in proton-proton collisions at a center-of-mass energy of 13 TeV at the CERN LHC with the CMS detector in 2016–2018, and correspond to an integrated luminosity of 138 fb$^{-1}$. No significant excess is seen with respect to standard model expectations. Upper limits on cross sections for the pair production of $τ$ sleptons are obtained in the framework of simplified models. In a scenario in which the $τ$ sleptons are superpartners of left-handed $τ$ leptons, and each undergoes a prompt decay to a $τ$ lepton and a nearly massless LSP, $τ$ slepton masses between 115 and 340 GeV are excluded. In a scenario in which the lifetime of the $τ$ sleptons corresponds to $cτ_0$ = 0.1 mm, where $τ_0$ represents the mean proper lifetime of the $τ$ slepton, masses between 150 and 220 GeV are excluded