290 research outputs found

    Interaction of PARP2 with DNA structures mimicking DNA repair intermediates

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    Poly(ADP-ribosyl)ation is a posttranslational protein modification significant for the genomic stability and cell survival in response to DNA damage. Poly(ADP-ribosyl)ation is catalyzed by poly(ADP-ribose)polymerases (PARPs). Whereas the role of PARP1 in response to DNA damage has been widely illustrated, the contribution of another DNA-dependent PARP, PARP2, has not been studied so far. Aim. To find out specific DNA targets of PARP2. Methods. The EMSA and the PARP activity tests were used. Results. We evaluated Kd values of PARP2-DNA complexes for several DNA structures mimicking intermediates of different DNA metabolizing processes and tested these DNA as «activators» of PARP1 and PARP2 in poly(ADP-ribose) synthesis. Conclusions. Like PARP1, PARP2 does not show correlation between the activation efficiency and Kd values for DNA. PARP2 was activated most effectively in the presence of over5DNA. Keywords: PARP1, PARP2, poly(ADP-ribosyl)ation, DNA binding.Полі(ADP-рибозил)ювання – це тип посттрансляційної модифікації білків, який є важливим для забезпечення стабільності геному та виживання клітин у відповідь на пошкодження ДНК. Полі (ADP-рибозил)ювання каталізується полі(ADP-рибоза)полімеразами (PARP). У той час як роль PARP1 у клітинній відповіді на пошкодження ДНК детально досліджено, внесок іншої ДНК-залежної полі(ADP-рибоза)полімерази – PARP2 – вивчено поки що слабко. Мета. Виявити специфічні ДНК-мішені PARP2. Методи. Метод «затримки в гелі» (EMSA) і тест активності PARP. Результати. Проведено оціночні виміри значень Kd комплексів PARP2–ДНК для деяких структур ДНК, імітуючих інтермедіати різних процесів метаболізму ДНК, а також ці ДНК проаналізовано як «активатори» PARP1 і PARP2 у синтезі полі(ADP-рибози). Висновки. Як і для PARP1, для PARP2 не спостерігається кореляції між ефективністю активації та значенням Kd для різних ДНК. Найефективніше PARP2 активується за присутності over5DNA. Ключові слова: PARP1, PARP2, полі(ADP-рибозил)ювання, зв’язування ДНК

    Jatropha curcasand Ricinus communisdisplay contrasting photosynthetic mechanisms in response to environmental conditions

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    Higher plants display different adaptive strategies in photosynthesis to cope with abiotic stress. In this study, photosynthetic mechanisms and water relationships displayed byJatropha curcasL. (physic nuts) andRicinus communisL. (castor bean), in response to variations in environmental conditions, were assessed.R. communis showed higher CO2 assimilation, stomatal and mesophyll conductance thanJ. curcas as light intensity and intercellular CO2 pressure increased. On the other hand,R. communis was less effective in stomatal control in response to adverse environmental factors such as high temperature, water deficit and vapor pressure deficit, indicating lower water use efficiency. Conversely,J. curcas exhibited higher photosynthetic efficiency (gas exchange and photochemistry) and water use efficiency under these adverse environmental conditions.R. communisdisplayed higher potential photosynthesis, but exhibited a lowerin vivo Rubisco carboxylation rate (Vcmax) and maximum electron transport rate (Jmax). During the course of a typical day, in a semiarid environment, with high irradiation, high temperature and high vapor pressure deficit, but exposed to well-watered conditions, the two studied species presented similar photosynthesis. Losing potential photosynthesis, but maintaining favorable water status and increasing non-photochemical quenching to avoid photoinhibition, are important acclimation mechanisms developed byJ. curcas to cope with dry and hot conditions. We suggest thatJ. curcas is more tolerant to hot and dry environments thanR. communis but the latter species displays higher photosynthetic efficiency under well-watered and non-stressful conditions

    Perfil dos bolsistas de produtividade do Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) na área de Medicina Veterinária

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    No presente estudo, submeteram-se dados da população de bolsistas de produtividade do Comitê de Medicina Veterinária do Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ao cálculo de índices cientométricos, em um esforço para avaliar o perfil de pesquisadores de diferentes níveis perante vários parâmetros. Outras variáveis, como o local de formação, gênero, local de trabalho e formação de recursos humanos foram também anotados e avaliados. Há uma clara predominância do gênero masculino (72,37%), os quais se encontram em sua grande maioria radicados nas regiões Sul e Sudeste do país. A maioria dos bolsistas concluiu seu doutorado no Brasil. Dentre os parâmetros de produção analisados, a formação de recursos humanos é alta em todos os níveis; dentre as variáveis cientométricas, os índices de citações e o índice h são decrescentes do nível mais alto (PQ-1A) ao nível 2; todavia, a variação intragrupos é muito alta para estes e outros derivado do índice h. Uma modificação do índice H, o índice AWCR, em que o cálculo leva em conta a idade dos artigos publicados e citados, parece mais adequado à estratificação dos bolsistas. No âmbito geral, estudos deste tipo poderiam ser repetidos no médio prazo com vistas a aprimorar as fórmulas de ranqueamento de bolsistas

    Diagnostic host gene signature for distinguishing enteric fever from other febrile diseases

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    Misdiagnosis of enteric fever is a major global health problem, resulting in patient mismanagement, antimicrobial misuse and inaccurate disease burden estimates. Applying a machine learning algorithm to host gene expression profiles, we identified a diagnostic signature, which could distinguish culture‐confirmed enteric fever cases from other febrile illnesses (area under receiver operating characteristic curve > 95%). Applying this signature to a culture‐negative suspected enteric fever cohort in Nepal identified a further 12.6% as likely true cases. Our analysis highlights the power of data‐driven approaches to identify host response patterns for the diagnosis of febrile illnesses. Expression signatures were validated using qPCR, highlighting their utility as PCR‐based diagnostics for use in endemic settings

    Search for Eccentric Binary Black Hole Mergers with Advanced LIGO and Advanced Virgo during Their First and Second Observing Runs

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    When formed through dynamical interactions, stellar-mass binary black holes (BBHs) may retain eccentric orbits (e > 0.1 at 10 Hz) detectable by ground-based gravitational-wave detectors. Eccentricity can therefore be used to differentiate dynamically formed binaries from isolated BBH mergers. Current template-based gravitational-wave searches do not use waveform models associated with eccentric orbits, rendering the search less efficient for eccentric binary systems. Here we present the results of a search for BBH mergers that inspiral in eccentric orbits using data from the first and second observing runs (O1 and O2) of Advanced LIGO and Advanced Virgo. We carried out the search with the coherent WaveBurst algorithm, which uses minimal assumptions on the signal morphology and does not rely on binary waveform templates. We show that it is sensitive to binary mergers with a detection range that is weakly dependent on eccentricity for all bound systems. Our search did not identify any new binary merger candidates. We interpret these results in light of eccentric binary formation models. We rule out formation channels with rates ⪆100 Gpc-3 yr-1 for e > 0.1, assuming a black hole mass spectrum with a power-law index ≲2

    Low-latency Gravitational-wave Alerts for Multimessenger Astronomy during the Second Advanced LIGO and Virgo Observing Run

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    Advanced LIGO's second observing run (O2), conducted from 2016 November 30 to 2017 August 25, combined with Advanced Virgo's first observations in 2017 August, witnessed the birth of gravitational-wave multimessenger astronomy. The first ever gravitational-wave detection from the coalescence of two neutron stars, GW170817, and its gamma-ray counterpart, GRB 170817A, led to an electromagnetic follow-up of the event at an unprecedented scale. Several teams from across the world searched for EM/neutrino counterparts to GW170817, paving the way for the discovery of optical, X-ray, and radio counterparts. In this article, we describe the online identification of gravitational-wave transients and the distribution of gravitational-wave alerts by the LIGO and Virgo collaborations during O2. We also describe the gravitational-wave observables that were sent in the alerts to enable searches for their counterparts. Finally, we give an overview of the online candidate alerts shared with observing partners during O2. Alerts were issued for 14 candidates, 6 of which have been confirmed as gravitational-wave events associated with the merger of black holes or neutron stars. Of the 14 alerts, 8 were issued less than an hour after data acquisition

    GW190521 : A Binary Black Hole Merger with a Total Mass of 150  M_{⊙}

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    On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 85_{-14}^{+21}  M_{⊙} and 66_{-18}^{+17}  M_{⊙} (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of being below 65  M_{⊙}. We calculate the mass of the remnant to be 142_{-16}^{+28}  M_{⊙}, which can be considered an intermediate mass black hole (IMBH). The luminosity distance of the source is 5.3_{-2.6}^{+2.4}  Gpc, corresponding to a redshift of 0.82_{-0.34}^{+0.28}. The inferred rate of mergers similar to GW190521 is 0.13_{-0.11}^{+0.30}  Gpc^{-3} yr^{-1}
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