Phosphatase activity of H+-ATPase from chloroplasts

AbstractThe chloroplast H+-ATPase (CF0F1) was purified from spinach chloroplasts and studied both in the soluble state and after reconstitution into asolectin liposomes. Hydrolysis of ATP and of p-nitrophenylphosphate (p-NPP) catalysed by CF0F1 was investigated. (1) Soluble, isolated CF0F1 catalyzes ATP hydrolysis and p-NPP hydrolysis. (2) ATP inhibits the phosphatase activity in the latent state (Ki=1.7 mM). (3) Addition of 100 mM sulfite increases the rate of ATP hydrolysis by a factor of 10, while p-NPP hydrolysis is completely abolished. (4) CF0F1 reconstituted into asolectin vesicles catalyzes ATP hydrolysis and p-NPP hydrolysis. When the enzyme is brought into its active state by a ΔpH/Δϕ jump, ATP hydrolysis is increased by a factor of 8, and p-NPP hydrolysis is completely abolished. (5) ATP hydrolysis by the activated enzyme is inhibited by p-NPP (Ki=1.6 mM). (6) p-NPP also inhibits ATP synthesis by the activated enzyme, competing with phosphate (Ki=0.9 mM). These results show that in the active state of CF0F1, p-NPP is not hydrolyzed but acts as a competitive inhibitor; in the inactive state of CF0F1, p-NPP is hydrolyzed. Hydrolysis of p-NPP might be used as an assay for the inactive forms of CF0F1

Promoção do Ensino de Programação e Robótica a Estudantes de Escolas da Rede Pública de Ensino na Cidade de Divinópolis-MG

Este artigo aborda o desenvolvimento de um projeto de ensino de programação e robótica a estudantes da rede pública de ensino na cidade de Divinópolis - MG. Nele, alunos dos 8o e 9o anos do Ensino Fundamental são incentivados a criar programas de computador e robôs autônomos, o que estimula, respectivamente, a criatividade e o pensamento lógico-aritmético desenvolvidos durante a programação dos computadores e a montagem dos robôs. Dessa maneira, acredita-se que esses adolescentes, ao serem expostos a conhecimentos extracurriculares da área de Informática, possam ampliar sua capacidade cognitiva de abstração e pensamento lógico prematuramente, o que afetaria positivamente seu rendimento escolar em componentes curriculares Exatos

The initial conditions of isolated star formation - VI. SCUBA mapping of prestellar cores

Observations have been carried out with SCUBA at the JCMT of 52 molecular cloud cores that do not contain any sign of protostellar activity. These are all therefore candidate prestellar cores, which are believed to represent the stage of star formation that precedes the formation of a protostar. 29 of the 52 cores were detected at 850 microns at varying levels of signal-to-noise ratio greater than 3 sigma at peak. The detected cores were split into 'bright' cores and `intermediate' cores, depending on their peak flux density at 850 microns. Cores with peak 850 microns flux densities greater than 170 mJy/beam were designated 'bright' (13 cores), while those flux densities below this value were designated 'intermediate' (16 cores). This dividing line corresponds to A_v~50 under typical assumptions. The data are combined with our previously published ISO data, and the physical parameters of the cores, such as density and temperature, are calculated. Detailed fitting of the bright core radial profiles shows that they are not critical Bonnor-Ebert spheres, in agreement with previous findings. However, we find that intermediate cores, such as B68 (which has previously been claimed to be a Bonnor-Ebert sphere), may in fact be consistent with the Bonnor-Ebert criterion, suggesting perhaps that cores pass through such a phase during their evolution. We make rough estimates of core lifetimes based on the statistics of detections and find that the lifetime of a prestellar core is roughly ~3x10^5 years, while that of a bright core is \~1.5x10^5 years. Comparisons with some magnetic and turbulence regulated collapse models show that no model can match all of the data. Models that are tuned to fit the total prestellar core lifetime, do not predict the relative numbers of cores seen at each stage.Comment: 23 pages, 52 figures, accepted by MNRAS, alternate PDF w/all figures available from http://www.astro.cf.ac.uk/pub/Derek.Ward-Thompson/publications.htm

AVALIAÇÃO DA SENSIBILIDADE DE ANTIMICROBIANOS A CEPAS DE ENTEROBACTERIACEAE ISOLADAS DE AMOSTRAS DE ALFACE (Lactuca sativa) COMERCIALIZADA NA CIDADE DE SÃO LUÍS-MA

Objetivou-se verificar a sensibilidade de cepas de Citrobacter freundii, Escherichia coli, Serratia marcescens, Klebsiella pneumoniae e Enterobacter aerogenes, isoladas de alface (Lactuca sativa), comercializada na cidade de São Luís-MA (Brasil), frente a vários antimicrobianos. As 41 amostras coletadas em cinco feiras de produtos hortifrutigranjeiros foram submetidas ao método rápido API-20E (bio-Mérieux) e ao teste de sensibilidade a antimicrobianos (método de Kirby-Bauer). Os antibióticos testados foram: cefalotina (CFL, 20 µg), ampicilina (AMP, 10 µg), gentamicina (GEN, 10 µg), cloranfenicol (CLO, 30 µg), tetraciclina (TET, 30 µg), cefoxitina (CFO, 30 µg), cefotaxima (CTX, 30 µg) e ácido pipemídico (PIP, 30 µg). Os resultados evidenciaram que, excetuando-se a cefotaxima, todas as cepas foram resistentes aos antibióticos testados. Constatou-se ainda que a Klebsiella pneumoniae, cepa mais resistente aos antimicrobianos, apresentou multirresistência a CFL, AMP, GEM, CLO, TET, CFO e PIP. Os achados permitem concluir que as alfaces comercializadas em feiras da cidade de São Luís devem ser consumidas com cautela, considerando a potencialidade de contaminação por cepas de enterobactérias multirresitentes a antimicrobianos. Sugerese assim, cuidadosa desinfecção dessas hortaliças como medida de segurança alimentar

Arcuate AgRP, but not POMC neurons, modulate paraventricular CRF synthesis and release in response to fasting

Background: The activation of the hypothalamic–pituitary–adrenal (HPA) axis is essential for metabolic adaptation in response to fasting. However, the neurocircuitry connecting changes in the peripheral energy stores to the activity of hypothalamic paraventricular corticotrophin-releasing factor (CRFPVN) neurons, the master controller of the HPA axis activity, is not completely understood. Our main goal was to determine if hypothalamic arcuate nucleus (ARC) POMC and AgRP neurons can communicate fasting-induced changes in peripheral energy stores, associated to a fall in plasma leptin levels, to CRFPVN neurons to modulate the HPA axis activity in mice. Results: We observed increased plasma corticosterone levels associate with increased CRFPVN mRNA expression and increased CRFPVN neuronal activity in 36 h fasted mice. These responses were associated with a fall in plasma leptin levels and changes in the mRNA expression of Agrp and Pomc in the ARC. Fasting-induced decrease in plasma leptin partially modulated these responses through a change in the activity of ARC neurons. The chemogenetic activation of POMCARC by DREADDs did not affect fasting-induced activation of the HPA axis. DREADDs inhibition of AgRPARC neurons reduced the content of CRFPVN and increased its accumulation in the median eminence but had no effect on corticosterone secretion induced by fasting. Conclusion: Our data indicate that AgRPARC neurons are part of the neurocircuitry involved in the coupling of PVNCRF activity to changes in peripheral energy stores induced by prolonged fasting.Fil: Alves Fernandes, Alan Carlos. University Of Ribeirao Preto; BrasilFil: Pereira de Oliveira, Franciane. Universidade Federal de Sao Paulo.; BrasilFil: Fernandez, Gimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: da Guia Vieira, Luane. University Of Ribeirao Preto; BrasilFil: Gugelmin Rosa, Cristiane. University Of Ribeirao Preto; BrasilFil: do Nascimento, Taís. University Of Ribeirao Preto; BrasilFil: de Castro França, Suzelei. University Of Ribeirao Preto; BrasilFil: Donato Jr, Jose. Universidade de Sao Paulo. Departamento de Fisiología; BrasilFil: Vella, Kristen R.. Weill Cornell Medical College; Estados UnidosFil: Antunes Rodrigues, Jose. University Of Ribeirao Preto; BrasilFil: Mecawi , André. Universidade Federal de Sao Paulo.; BrasilFil: Perello, Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: Leico Kagohara Elias, Lucila. University Of Ribeirao Preto; BrasilFil: Rorato, Rodrigo. Universidade Federal de Sao Paulo.; Brasi

Promoção do ensino de programação e robótica a estudantes de escolas da rede pública de ensino na cidade de Divinópolis

Este artigo aborda o desenvolvimento de um projeto de ensino de programação e robótica a estudantes da rede pública de ensino na cidade de Divinópolis - MG. Nele, alunos dos 8º e 9º anos do Ensino Fundamental são guiados a criar robôs autônomos e programas de computador, o que estimula, respectivamente, a criatividade e o pensamento lógico-aritmético, desenvolvidos durante a montagem dos robôs e a programação dos computadores. Dessa maneira, acredita-se que esses adolescentes, ao serem expostos a conhecimentos extracurriculares da área de Informática, possam ampliar sua capacidade cognitiva de abstração e pensamento lógico prematuramente, o que afetaria positivamente em seu rendimento escolar em componentes curriculares Exatos

High anti-SARS-CoV-2 antibody seroconversion rates before the second wave in Manaus, Brazil, and the protective effect of social behaviour measures: results from the prospective DETECTCoV-19 cohort

Background: The city of Manaus, Brazil, has seen two collapses of the health system due to the COVID-19 pandemic. We report anti-SARS-CoV-2 nucleocapsid IgG antibody seroconversion rates and associated risk factors in Manaus residents before the second wave of the epidemic in Brazil. Methods: A convenience sample of adult (aged ≥18 years) residents of Manaus was recruited through online and university website advertising into the DETECTCoV-19 study cohort. The current analysis of seroconversion included a subgroup of DETECTCoV-19 participants who had at least two serum sample collections separated by at least 4 weeks between Aug 19 and Oct 2, 2020 (visit 1), and Oct 19 and Nov 27, 2020 (visit 2). Those who reported (or had no data on) having a COVID-19 diagnosis before visit 1, and who were positive for anti-SARS-CoV-2 nucleocapsid IgG antibodies at visit 1 were excluded. Using an in-house ELISA, the reactivity index (RI; calculated as the optical density ratio of the sample to the negative control) for serum anti-SARS-CoV-2 nucleocapsid IgG antibodies was measured at both visits. We calculated the incidence of seroconversion (defined as RI values ≤1·5 at visit 1 and ≥1·5 at visit 2, and a ratio >2 between the visit 2 and visit 1 RI values) during the study period, as well as incidence rate ratios (IRRs) through cluster-corrected and adjusted Poisson regression models to analyse associations between seroconversion and variables related to sociodemographic characteristics, health access, comorbidities, COVID-19 exposure, protective behaviours, and symptoms. Findings: 2496 DETECTCoV-19 cohort participants returned for a follow-up visit between Oct 19 and Nov 27, 2020, of whom 204 reported having COVID-19 before the first visit and 24 had no data regarding previous disease status. 559 participants were seropositive for anti-SARS-CoV-2 nucleocapsid IgG antibodies at baseline. Of the remaining 1709 participants who were seronegative at baseline, 71 did not meet the criteria for seroconversion and were excluded from the analyses. Among the remaining 1638 participants who were seronegative at baseline, 214 showed seroconversion at visit 2. The seroconversion incidence was 13·06% (95% CI 11·52–14·79) overall and 6·78% (5·61–8·10) for symptomatic seroconversion, over a median follow-up period of 57 days (IQR 54–61). 48·1% of seroconversion events were estimated to be asymptomatic. The sample had higher proportions of affluent and higher-educated people than those reported for the Manaus city population. In the fully adjusted and corrected model, risk factors for seroconversion before visit 2 were having a COVID-19 case in the household (IRR 1·49 [95% CI 1·21–1·83]), not wearing a mask during contact with a person with COVID-19 (1·25 [1·09–1·45]), relaxation of physical distancing (1·31 [1·05–1·64]), and having flu-like symptoms (1·79 [1·23–2·59]) or a COVID-19 diagnosis (3·57 [2·27–5·63]) between the first and second visits, whereas working remotely was associated with lower incidence (0·74 [0·56–0·97]). Interpretation: An intense infection transmission period preceded the second wave of COVID-19 in Manaus. Several modifiable behaviours increased the risk of seroconversion, including non-compliance with non-pharmaceutical interventions measures such as not wearing a mask during contact, relaxation of protective measures, and non-remote working. Increased testing in high-transmission areas is needed to provide timely information about ongoing transmission and aid appropriate implementation of transmission mitigation measures. Funding: Ministry of Education, Brazil; Fundação de Amparo à Pesquisa do Estado do Amazonas; Pan American Health Organization (PAHO)/WHO.World Health OrganizationRevisión por pare

The Oldest Case of Decapitation in the New World (Lapa do Santo, East-Central Brazil)

We present here evidence for an early Holocene case of decapitation in the New World (Burial 26), found in the rock shelter of Lapa do Santo in 2007. Lapa do Santo is an archaeological site located in the Lagoa Santa karst in east-central Brazil with evidence of human occupation dating as far back as 11.7-12.7 cal kyBP (95.4% interval). An ultra-filtered AMS age determination on a fragment of the sphenoid provided an age range of 9.1-9.4 cal kyBP (95.4% interval) for Burial 26. The interment was composed of an articulated cranium, mandible and first six cervical vertebrae. Cut marks with a v-shaped profile were observed in the mandible and sixth cervical vertebra. The right hand was amputated and laid over the left side of the face with distal phalanges pointing to the chin and the left hand was amputated and laid over the right side of the face with distal phalanges pointing to the forehead. Strontium analysis comparing Burial 26's isotopic signature to other specimens from Lapa do Santo suggests this was a local member of the group. Therefore, we suggest a ritualized decapitation instead of trophy-taking, testifying for the sophistication of mortuary rituals among hunter-gatherers in the Americas during the early Archaic period. In the apparent absence of wealth goods or elaborated architecture, Lapa do Santo's inhabitants seemed to use the human body to express their cosmological principles regarding death

Fungal Systematics and Evolution: FUSE 8

In this 8th contribution to the Fungal Systematics and Evolution series published by Sydowia, the authors formally describe 11 species: Cortinarius caryae, C. flavolilacinus, C. lilaceolamellatus, C. malodorus, C. olivaceolamellatus, C. quercophilus, C. violaceoflavescens, C. viridicarneus, Entoloma meridionale (Agaricales), Hortiboletus rupicapreus (Boletales), and Paraglomus peruvianum (Paraglomerales). The following new country records are reported: Bolbitius callistus (Agaricales) from Russia and Hymenoscyphus equiseti (Helotiales) from Sweden. Hymenoscyphus equiseti is proposed as a new combination for Lanzia equiseti, based on ITS and LSU sequence data in combination with morphological study

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio