4,297 research outputs found

    Exocytosis of catecholamine (CA)-containing and CA-free granules in chromaffin cells.

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    Recent evidence suggests that endocytosis in neuroendocrine cells and neurons can be tightly coupled to exocytosis, allowing rapid retrieval from the plasma membrane of fused vesicles for future use. This can be a much faster mechanism for membrane recycling than classical clathrin-mediated endocytosis. During a fast exo-endocytotic cycle, the vesicle membrane does not fully collapse into the plasma membrane; nevertheless, it releases the vesicular contents through the fusion pore. Once the vesicle is depleted of transmitter, its membrane is recovered without renouncing its identity. In this report, we show that chromaffin cells contain catecholamine-free granules that retain their ability to fuse with the plasma membrane. These catecholamine-free granules represent 7% of the total population of fused vesicles, but they contributed to 47% of the fusion events when the cells were treated with reserpine for several hours. We propose that rat chromaffin granules that transiently fuse with the plasma membrane preserve their exocytotic machinery, allowing another round of exocytosis

    Niche differentiation mechanisms among canopy frugivores and zoochoric trees in the northeastern extreme of the Amazon

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    Frugivores and zoocoric trees represent an important proportion of tropical rainforest biodiversity. As niche differences favor species coexistence, we aimed to evaluate morphological and temporal niche segregation mechanisms among zoochoric trees and canopy frugivores in a tropical rainforest in the northeastern extreme of the Brazilian Amazon. We tested the effects of fruit morphology, tree size, frugivore body size and time of day on fruit consumption. We recorded the frugivore species that fed on 72 trees (44 species, 22 genera) and whether these frugivores swallowed the seeds. We monitored trees only once from 07:00 to 17:00 h between January and September 2017. We observed fruit consumption in 20 of the 72 trees. Seventy-three frugivore individuals from 22 species visited the trees. Heavier fruits were consumed by larger frugivores, while seed size was inversely correlated with frugivore size. Narrower fruits and fruits with smaller seeds had greater probability of having their seeds ingested, and larger frugivores were more prone to ingest seeds. Trees bearing fruits with smaller seeds were visited by a greater number of frugivores. Taxonomic groups differed in the time of arrival at fruiting trees. None of the evaluated variables (fruit weight and size, and seed size) affected the richness of frugivores that visited the trees. We concluded that, in the studied forest, fruit morphology (weight, size and seed size) is a niche segregation mechanism among zoochoric trees, while body size and time of day are niche segregation mechanisms among frugivores.info:eu-repo/semantics/publishedVersio

    Tumor Necrosis Factor-alpha Levels In Blood Cord Is Directly Correlated With The Body Weight Of Mothers

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    Obesity has emerged as major public health problem leading to increased morbidity and mortality. Epidemiological studies indicate that in many regions of the world, children and teenagers are increasingly affected by obesity, which contributes for a pessimistic projection for the near future. Maternal obesity has been implicated in metabolic disorders of the offspring, but there are no biological markers that can be detected early on life that predict the development of obesity in the offspring. Objective To evaluate the expression of inflammatory markers in the umbilical cord blood of babies of mothers with obesity/overweight, and correlate these markers with the body weight at age 9 months. Methods Anthropometric data of mothers and babies were obtained during prenatal evaluation, at birth and 9 months after birth. Cord blood was collected during delivery of 54 babies from mothers with obesity/overweight and of 50 babies from lean mothers. Tumour necrosis factor-alpha (TNF-alpha), transforming growth factor 1 beta, monocyte chemoattractant protein-1 and 2 (MCP-1/MCP-2) were determined in serum samples using enzyme-linked immunosorbent assay methods. Correlations were evaluated using the Spearman correlation coefficient, and comparisons were evaluated using the non-parametric Mann-Whitney U-test. Results Cord blood TNF-a was positively correlated with maternal body mass index. There was an inverse correlation between cord blood transforming growth factor 1 beta and baby body weight at birth. There was no biological marker that predicted body weight at age 9 months. Conclusion Although we have not found a biological marker to predict increased body weight at 9 months of age, the study shows that maternal obesity exposes the baby to higher TNF-a level in the early stages of life, and this can affect metabolic and inflammatory parameters during adulthood.2221021

    Genetic control of soybean resistance to brown spot (Septoria glycines): first studies.

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    Knowledge of the genetic effects that control a trait is essential to direct the breeding program for gains in the selection process. The main objective of this study was to investigate the genetic control of soybean resistance to brown spot. Two tolerant cultivars (FT-2 and Dourados) and two susceptible cultivars (Davis and Paraná) and the segregant F2 and F3 generations derived from the crosses between these cultivars were assessed for reaction to the disease after inoculation. Genetic models were adjusted to the means and variances of the generations. It could be concluded that the trait is governed by various genes with lesser effect, has low to medium heritability and selection should be made always using progeny from the F3 generation and can be made during the initial stages of soybean growth, based on the mean of at least two trifoliate leaves

    Redescription of the advertisement call of five species of Thoropa (anura, Cycloramphidae), including recordings of rare and endangered species

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Frogs of the genus Thoropa comprise six endemic Brazilian species on the Eastern side of the country. Little is known about their natural history, especially about their acoustic communication. Therefore, aiming to provide an overview of their vocalizations, we analyzed and redescribed male advertisement calls of three living and two possibly extinct species. The Smaller species, T. petropolitana and T. lutzi, produce simple calls (one single note) with a higher frequency range than the remaining larger ones. On the other hand, the larger species present complex calls, with more than one note: T. megatympanum calls have three notes, T. taophora calls have four notes, and T. miliaris calls varies from three to six notes. Population snout-vent length negatively correlated with peak of dominant frequency as expected. However, highlighted differences between two populations of T. lutzi, which could indicate need of further taxonomic evaluation of those lineages. Peculiar morphology, such as the absence of vocal sacs and slits, may have contributed to their call variation and highly banded frequency structure. If the observed population differences reflect species-level differences, T. lutzi may be classified as a critically endangered species, as T. petropolitana. Furthermore, we provided a suggestion to an unusual behavior in frogs: calling with the mouth open in the Smaller species of the genus.Frogs of the genus Thoropa comprise six endemic Brazilian species on the Eastern side of the country. Little is known about their natural history, especially about their acoustic communication. Therefore, aiming to provide an overview of their vocalizatio119112FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNQP - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)2014/23388-72013/09964-2405285/2013-2302589/2013-9306732/2015-7SEM INFORMAÇÃOWe thank to Pedro CarvalhoRocha for helping with the analysis of the calls of T. lutzi, we also thank Rogério P. Bastos and Rafael Márquez for valuable comments in the last version of this manuscript. This work was funded by: São Paulo Research Foundatio

    From Mendel to genomics, plant breeding milestones: a review.

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    Plant breeding has evolved from an intuitive strategy of choosing the best plants in the field to an exciting science of combining genes to improve desirable traits. Our objective with this paper is to review some of the most important discoveries and developments that had an impact on plant breeding. First, we present background information and then the milestones themselves. The topics were grouped into chapters to facilitate comprehension of their contribution to plant breeding. They are discussed within each chapter in a plant-breeding-oriented chronological way. When applicable, the definition, importance and evaluation of the topics are presente
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