588 research outputs found
Reduced Expression of the Vesicular Acetylcholine Transporter and Neurotransmitter Content Affects Synaptic Vesicle Distribution and Shape in Mouse Neuromuscular Junction
In vertebrates, nerve muscle communication is mediated by the release of the neurotransmitter acetylcholine packed inside synaptic vesicles by a specific vesicular acetylcholine transporter (VAChT). Here we used a mouse model (VAChT KDHOM) with 70% reduction in the expression of VAChT to investigate the morphological and functional consequences of a decreased acetylcholine uptake and release in neuromuscular synapses. Upon hypertonic stimulation, VAChT KDHOM mice presented a reduction in the amplitude and frequency of miniature endplate potentials, FM 1-43 staining intensity, total number of synaptic vesicles and altered distribution of vesicles within the synaptic terminal. In contrast, under electrical stimulation or no stimulation, VAChT KDHOM neuromuscular junctions did not differ from WT on total number of vesicles but showed altered distribution. Additionally, motor nerve terminals in VAChT KDHOM exhibited small and flattened synaptic vesicles similar to that observed in WT mice treated with vesamicol that blocks acetylcholine uptake. Based on these results, we propose that decreased VAChT levels affect synaptic vesicle biogenesis and distribution whereas a lower ACh content affects vesicles shape
The SWR1 Histone Replacement Complex Causes Genetic Instability and Genome-Wide Transcription Misregulation in the Absence of H2A.Z
The SWR1 complex replaces the canonical histone H2A with the variant H2A.Z (Htz1 in yeast) at specific chromatin regions. This dynamic alteration in nucleosome structure provides a molecular mechanism to regulate transcription, gene silencing, chromosome segregation and DNA repair. Here we show that genetic instability, sensitivity to drugs impairing different cellular processes and genome-wide transcriptional misregulation in htz1Î can be partially or totally suppressed if SWR1 is not formed (swr1Î), if it forms but cannot bind to chromatin (swc2Î) or if it binds to chromatin but lacks histone replacement activity (swc5Î and the ATPase-dead swr1-K727G). These results suggest that in htz1Î the nucleosome remodelling activity of SWR1 affects chromatin integrity because of an attempt to replace H2A with Htz1 in the absence of the latter. This would impair transcription and, either directly or indirectly, other cellular processes. Specifically, we show that in htz1Î, the SWR1 complex causes an accumulation of recombinogenic DNA damage by a mechanism dependent on phosphorylation of H2A at Ser129, a modification that occurs in response to DNA damage, suggesting that the SWR1 complex impairs the repair of spontaneous DNA damage in htz1Î. In addition, SWR1 causes DSBs sensitivity in htz1Î; consistently, in the absence of Htz1 the SWR1 complex bound near an endonuclease HO-induced DSB at the mating-type (MAT) locus impairs DSB-induced checkpoint activation. Our results support a stepwise mechanism for the replacement of H2A with Htz1 and demonstrate that a tight control of this mechanism is essential to regulate chromatin dynamics but also to prevent the deleterious consequences of an incomplete nucleosome remodelling
Dynamics of early establishment of SARS-CoV-2 VOC Omicron lineages in Minas Gerais, Brazil
Brazil is one of the nations most affected by Coronavirus disease 2019 (COVID-19). The introduction and establishment of new virus variants can be related to an increase in cases and fatalities. The emergence of Omicron, the most modified SARS-CoV-2 variant, caused alarm for the public health of Brazil. In this study, we examined the effects of the Omicron introduction in Minas Gerais (MG), the second-most populous state of Brazil. A total of 430 Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) samples from November 2021 to June 2022 from Belo Horizonte (BH) city were sequenced. These newly sequenced genomes comprise 72% of all previously available SARS-CoV-2 genomes for the city. Evolutionary analysis of novel viral genomes reveals that a great diversity of Omicron sublineages have circulated in BH, a pattern in-keeping with observations across Brazil more generally. Bayesian phylogeographic reconstructions indicate that this diversity is a product of a large number of international and national importations. As observed previously, SĂŁo Paulo state is shown as a significant hub for viral spread throughout the country, contributing to around 70% of all viral Omicron introductions detected in MG
Prospective study of patients with persistent symptoms of dengue in Brazil
Dengue is an arboviral infection clinically recognized as an acute and self-limited disease. Persistence of dengue symptoms is known, but it has been little studied. The aim of this study was to characterize persistent symptoms in 113 patients with dengue followed up clinically and by laboratory testing at a tertiary hospital. Symptoms that persisted for more than 14 days were observed in 61 (54.0%) patients, and six (6.2%) of them had symptoms for 6 months or more. The persistent symptoms identified were myalgia, weakness, hair loss, memory loss, reduced resistance to physical effort, headache, reasoning problems, arthralgia, sleepiness- and emotional lability. The progression to persistent symptoms was significantly associated with hospitalization, older age, more severe disease, the presence of bleeding and comorbidities upon univariate analysis. Upon multivariate analysis, the presence of persistent symptoms continued to be significantly associated only with increased age and dengue with warning signs. The platelet count during the acute phase of the disease was significantly lower in the group with persistent symptoms. In conclusion, the frequency of progression to persistent symptoms in dengue is relevant in patients seen at a tertiary hospital and the persistence of symptoms is more common in patients with dengue with warning signs
Habitat and Scale Shape the Demographic Fate of the Keystone Sea Urchin Paracentrotus lividus in Mediterranean Macrophyte Communities
Demographic processes exert different degrees of control as individuals grow, and in species that span several habitats and spatial scales, this can influence our ability to predict their population at a particular life-history stage given the previous life stage. In particular, when keystone species are involved, this relative coupling between demographic stages can have significant implications for the functioning of ecosystems. We examined benthic and pelagic abundances of the sea urchin Paracentrotus lividus in order to: 1) understand the main life-history bottlenecks by observing the degree of coupling between demographic stages; and 2) explore the processes driving these linkages. P. lividus is the dominant invertebrate herbivore in the Mediterranean Sea, and has been repeatedly observed to overgraze shallow beds of the seagrass Posidonia oceanica and rocky macroalgal communities. We used a hierarchical sampling design at different spatial scales (100 s, 10 s and <1 km) and habitats (seagrass and rocky macroalgae) to describe the spatial patterns in the abundance of different demographic stages (larvae, settlers, recruits and adults). Our results indicate that large-scale factors (potentially currents, nutrients, temperature, etc.) determine larval availability and settlement in the pelagic stages of urchin life history. In rocky macroalgal habitats, benthic processes (like predation) acting at large or medium scales drive adult abundances. In contrast, adult numbers in seagrass meadows are most likely influenced by factors like local migration (from adjoining rocky habitats) functioning at much smaller scales. The complexity of spatial and habitat-dependent processes shaping urchin populations demands a multiplicity of approaches when addressing habitat conservation actions, yet such actions are currently mostly aimed at managing predation processes and fish numbers. We argue that a more holistic ecosystem management also needs to incorporate the landscape and habitat-quality level processes (eutrophication, fragmentation, etc.) that together regulate the populations of this keystone herbivore
A pesquisa sobre segurança alimentar e nutricional no Brasil de 2000 a 2005: tendências e desafios
Teste de Morisky-Green e Brief Medication Questionnaire para avaliar adesĂŁo a medicamentos
OBJETIVO: Analisar a confiabilidade e o desempenho da versĂŁo em portuguĂŞs de instrumentos de avaliação da adesĂŁo ao tratamento anti-hipertensivo. MĂTODOS: Pacientes hipertensos atendidos de janeiro a setembro de 2010 em uma unidade de atenção primĂĄria em Porto Alegre, RS, foram selecionados aleatoriamente (n = 206). Na avaliação da adesĂŁo foram utilizadas versĂľes em portuguĂŞs do Teste de Morisky-Green (TMG) e do Brief Medication Questionnaire (BMQ). Foram analisados consistĂŞncia interna, estabilidade temporal e desempenho com relação a trĂŞs padrĂľes-ouro: controle inadequado da pressĂŁo arterial (> 140/90 mmHg); taxa insuficiente de retirada de medicação na farmĂĄcia da Unidade BĂĄsica de SaĂşde (< 80%); e a combinação de ambos. RESULTADOS: Dos pacientes avaliados, 97 utilizavam medicamentos dispensados somente pela farmĂĄcia da Unidade BĂĄsica de SaĂşde. Os testes apresentaram boa consistĂŞncia interna: BMQ α de Cronbach de 0,66 (IC95% 0,60;0,73) e o TMG 0,73 (IC95% 0,67;0,79). O desempenho do BMQ no domĂnio regime apresentou sensibilidade de 77%, especificidade de 58% e ĂĄrea sob a curva ROC de 0,70 (IC95% 0,55;0,86), e o TMG sensibilidade de 61%, especificidade de 36% e ĂĄrea sob a curva ROC de 0,46 (IC95% 0,30;0,62). A correlação entre o BMQ e o TMG foi de r = 0,28, p > 0,001. A baixa adesĂŁo ao BMQ estĂĄ associada a maiores nĂveis tensionais quando comparada com pacientes aderentes (148,4 [dp 20,1] vs 128,8 [dp 17,8], p < 0,001), mas nĂŁo para o TMG. CONCLUSĂES: O BMQ apresentou melhor desempenho que o TMG, com maiores sensibilidade e especificidade. A avaliação da adesĂŁo pode auxiliar o clinico na discriminação entre uso inadequado da medicação e esquema terapĂŞutico insuficiente.OBJETIVO: Analizar la confiabilidad y el desempeĂąo de la versiĂłn en portuguĂŠs de instrumentos de evaluaciĂłn de la adherencia al tratamiento antihipertensivo. MĂTODOS: Pacientes hipertensos atendidos de enero a septiembre de 2010 en una unidad de atenciĂłn primaria en Porto Alegre, Sur de Brasil, fueron seleccionados aleatoriamente (n=206). En la evaluaciĂłn de la adherencia fueron utilizadas versiones en portuguĂŠs de la Prueba de Morisky-Green (TMG) y del Brief Medication Questionnarie (BMQ). Se analizaron consistencia interna, estabilidad temporal y desempeĂąo con relaciĂłn a tres patrones-oro: control inadecuado de la presiĂłn arterial (> 140/90 mmHg); tasa insuficiente de retirada de medicaciĂłn en la farmacia de la Unidad BĂĄsica de Salud (< 80%) y la combinaciĂłn de ambos. RESULTADOS: De los pacientes evaluados, 97 utilizaban medicamentos dispensados solamente por la farmacia de la Unidad BĂĄsica de Salud. Las pruebas presentaron buena consistencia interna: BMQ α de Cronbach de 0,66 (IC95% 0,60;0,73) y el TMG 0,73 (IC95% 0,67;0,79). El desempeĂąo del BMQ en el dominio rĂŠgimen presentĂł sensibilidad de 77%, especificidad de 58%, y ĂĄrea bajo la curva ROC de 0,70 (IC95% 0,55;0,86) y el TMG sensibilidad de 61%, especificidad de 36% y ĂĄrea bajo la curva ROC de 0,46 (IC95% 0,30;0,62). La correlaciĂłn entre el BMQ y el TMG fue de r=0,28, p>0,001. La baja adherencia al BMQ estĂĄ asociada a mayores niveles tensionales al compararlo con pacientes adherentes 148,4 [de 0,1] vs 128,8 [de 17,8], pOBJECTIVE: To analyze the reliability and performance of the Portuguese version of questionnaires used to evaluate adherence to hypertensive treatment. METHODS: Hypertensive patients attending a primary healthcare unit in Porto Alegre, Southern Brazil, from January to September 2010, were randomly selected (n = 206). To evaluate adherence, Portuguese versions of the Morisky-Green test (MGT) and the Brief Medication Questionnaire (BMQ) were used. The analysis considered internal consistency, temporal stability and performance compared to three gold standards, which are: inadequate control of blood pressure (BP > 140/90 mmHg); insufficient rate of medication acquisition at the institution's pharmacy
Pleosporales
One hundred and five generic types of Pleosporales are described and illustrated. A brief introduction and detailed history with short notes on morphology, molecular phylogeny as well as a general conclusion of each genus are provided. For those genera where the type or a representative specimen is unavailable, a brief note is given. Altogether 174 genera of Pleosporales are treated. Phaeotrichaceae as well as Kriegeriella, Zeuctomorpha and Muroia are excluded from Pleosporales. Based on the multigene phylogenetic analysis, the suborder Massarineae is emended to accommodate five families, viz. Lentitheciaceae, Massarinaceae, Montagnulaceae, Morosphaeriaceae and Trematosphaeriaceae
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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