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1.
Sci Total Environ ; 898: 165437, 2023 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-37437636

RESUMO

Oceans have been considered as an unlimited supply of goods and services, but resource extraction and waste disposal became ubiquitous and have been damaging the health of marine ecosystems. Finding suitable sentinel species of the human impacts on the oceans is thus imperative, since they may work as early warnings of disruptive situations. In this study, we investigated how taxonomy and foraging distribution influenced the occurrence of anthropogenic debris among five seabird species inhabiting the tropical Atlantic region. Occurrence of anthropogenic debris was assessed using faeces of breeding individuals as a proxy of ingestion. A total of 268 particles were extracted from all samples. The categories "fragments" and "fibres", as well as the colour "blue", were the most prevalent characteristics across species. There was a high diversity of polymers from cellulosic particles to synthetic plastics (Anthropogenic Cellulosic 26.9 %; Polyester 7.7 %; Varnish 5.8 %; Polypropylene 1.9 %). Species with a more coastal foraging strategy exhibited higher occurrence and number of anthropogenic debris when compared to species foraging comparably more in pelagic areas. This suggests that anthropogenic debris are more prevalent in coastal foraging areas, where human activities occur in higher number and frequency (e.g., fisheries) and sources of freshwater input from inland are at close distance. These results provide more evidence to the growing perception on the ubiquity and diversity of anthropogenic debris in the marine environment, and further support the usefulness of using seabirds as bio-indicators of anthropogenic pollution in both neritic and oceanic regions.


Assuntos
Ecossistema , Resíduos , Humanos , Animais , Resíduos/análise , Monitoramento Ambiental/métodos , Plásticos , Aves , Ingestão de Alimentos
2.
Braz J Biol ; 84: e260884, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35703638

RESUMO

Fluctuating asymmetry, defined as random differences between the two sides of a symmetrical structure, has been often related to development stress in both plants and animals. In plants, leaf fluctuating asymmetry has been related to stresses such as pollution and fire and may also be related to leaf growth and herbivory rates. We assessed whether leaf fluctuating asymmetry is related to plant and leaf size in Miconia albicans (Sw.) Triana (Melastomataceae), a common multi-stem Neotropical shrub, in a Brazilian savanna area. We collected 15 leaves from each of 70 individuals, and measured fluctuating asymmetry as the difference in area between the right and left sides of the leaves using the central vein as reference. To avoid spurious results due to measurement error, the division along the central vein was performed independently by three researchers. We also measured the basal area and height of each stem of the plant individuals. We used linear models to assess the relations between leaf fluctuating asymmetry, plant size and leaf size. No consistent relations were observed between leaf fluctuating asymmetry and plant size, as the analyses performed on the fluctuating asymmetry values obtained by the different researchers showed different results. However, relative fluctuating asymmetry values, obtained by dividing the fluctuating asymmetry by the total leaf area, tended to be smaller in larger leaves. It thus appears that, in the study species, fluctuating asymmetry is related to the developmental conditions faced by the individual leaves and not by the plant as a whole.


Assuntos
Incêndios , Melastomataceae , Animais , Herbivoria , Folhas de Planta , Plantas
4.
Phys Rev E ; 102(6-1): 062134, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33466017

RESUMO

The stochastic Liouville-von Neumann (SLN) equation describes the dynamics of an open quantum system reduced density matrix coupled to a non-Markovian harmonic environment. The interaction with the environment is represented by complex colored noises which drive the system, and whose correlation functions are set by the properties of the environment. We present a number of schemes capable of generating colored noises of this kind that are built on a noise amplitude reduction procedure [Imai et al., Chem. Phys. 446, 134 (2015)CMPHC20301-010410.1016/j.chemphys.2014.11.014], including two analytically optimized schemes. In doing so, we pay close attention to the properties of the correlation functions in Fourier space, which we derive in full. For some schemes the method of Wiener filtering for deconvolutions leads to the realization that weakening causality in one of the noise correlation functions improves numerical convergence considerably, allowing us to introduce a well-controlled method for doing so. We compare the ability of these schemes, along with an alternative optimized scheme [Schmitz and Stockburger, Eur. Phys. J.: Spec. Top. 227, 1929 (2019)1951-635510.1140/epjst/e2018-800094-y], to reduce the growth in the mean and variance of the trace of the reduced density matrix, and their ability to extend the region in which the dynamics is stable and well converged for a range of temperatures. By numerically optimizing an additional noise scaling freedom, we identify the scheme which performs best for the parameters used, improving convergence by orders of magnitude and increasing the time accessible by simulation.

5.
Braz. j. biol ; 78(3): 564-573, Aug. 2018. tab, graf
Artigo em Inglês | LILACS | ID: biblio-951568

RESUMO

Abstract Fire is a recurrent disturbance in savanna vegetation and savanna species are adapted to it. Even so, fire may affect various aspects of plant ecology, including phenology. We studied the effects of a spatially heterogeneous fire on the reproductive phenology of two dominant woody plant species, Miconia albicans (Melastomataceae) and Schefflera vinosa (Araliaceae), in a savanna area in South-eastern Brazil. The study site was partially burnt by a dry-season accidental fire in August 2006, and we monitored the phenolology of 30 burnt and 30 unburnt individuals of each species between September 2007 and September 2008. We used restricted randomizations to assess phenological differences between the burnt and unburnt individuals. Fire had negative effects on the phenology of M. albicans, with a smaller production of reproductive structures in general and of floral buds, total fruits, and ripe fruits in burnt plants. All unburnt but only 16% of the burnt M. albicans plants produced ripe fruits during the study. Fire effects on S. vinosa were smaller, but there was a greater production of floral buds and fruits (but not ripe fruits) by burnt plants; approximately 90% of the individuals of S. vinosa produced ripe fruits during the study, regardless of having been burnt or not. The differences between the two species may be related to S. vinosa's faster growth and absence from the seed bank at the study site, whereas M. albicans grows more slowly and is dominant in the seed bank.


Resumo O fogo é uma perturbação recorrente em vegetação savânica e as espécies do cerrado são adaptadas a ele. Mesmo assim, o fogo pode afetar aspectos da ecologia vegetal, incluindo a fenologia. Nós estudamos os efeitos de um incêndio espacialmente heterogêneo sobre a fenologia reprodutiva de duas espécies lenhosas dominantes, Miconia albicans (Melastomataceae) e Schefflera vinosa (Araliaceae), em uma área de cerrado no Sudeste do Brasil. A área de estudo foi parcialmente queimada por um incêndio acidental na estação seca (agosto) de 2006. Nós acompanhamos a fenologia reprodutiva de 30 indivíduos queimados e 30 não-queimados de cada espécie, de setembro de 2007 a setembro de 2008, usando aleatorizações restritas para comparar os dois grupos. Em M. albicans, a produção de estruturas reprodutivas como um todo e de botões florais, frutos e frutos maduros foi maior em indivíduos queimados do que nos não-queimados. Todos os indivíduos não-queimados, mas apenas 16% dos queimados, produziram frutos maduros durante o estudo. Já em S. vinosa, a produção de botões florais e de frutos (mas não de frutos maduros) foi maior em indivíduos queimados; aproximadamente 90% dos indivíduos de S. vinosa produziram frutos maduros durante o estudo, independentemente de terem sido queimados ou não. As diferenças entre as duas espécies podem estar relacionadas com o fato de S. vinosa crescer mais rápido e estar ausente do banco de sementes, ao contrário de M. albicans, de crescimento mais lento e dominante no banco de sementes.


Assuntos
Estações do Ano , Pradaria , Araliaceae/crescimento & desenvolvimento , Melastomataceae/crescimento & desenvolvimento , Incêndios , Brasil , Araliaceae/anatomia & histologia , Melastomataceae/anatomia & histologia
6.
Rev. andal. med. deporte ; 11(3): 0-0, sept. 2018. tab
Artigo em Inglês | IBECS | ID: ibc-181199

RESUMO

Objective: The aim of this study was to determine the association between physical fitness, socio-demographic factors and overweight prevalence of adolescent schoolchildren from urban and rural cities. Methods: The study population was made up of 377 male and female teenagers 14-17 years, enrolled in randomly selected public schools in urban and rural areas the northern Brazil. Socioeconomic status, flexibility, abdominal strength, endurance and cardiorespiratory fitness were measured. Results: The students from urban areas had a 55% (confidence interval of 95% = 1.12-2.12) more likely inadequacy physical quality and area of residence when compared to the rural area students. There was an association between muscular strength and endurance and area of residence. These odds ratio results demonstrated that the chances the students presented with inadequacy in this variable were 8.99 (confidence interval of 95% = 1.12-72.30) times higher among schoolchildren in rural compared to urban area. It was observed that 25.1% of teenagers found themselves with inadequate body composition, and the proportion of teenagers with inadequate body composition was higher (p < 0.05) for males (32.3%) compared to females (18%). Conclusion: It was concluded that there was an association between components of health related fitness and area of residence in the current study groups


Objetivo: El objetivo de este estudio fue determinar la asociación entre la condición física, los factores sociodemográficos y la prevalencia de sobrepeso en adolescentes escolares de municipios urbanos y rurales. Método: La población de estudio estaba compuesta por 377 adolescentes de ambos sexos de 14-17 años, escolarizados en centro públicos seleccionados al azar en zonas urbanas y rurales del norte de Brasil. Se midieron el estatus socioeconómico, la flexibilidad, la fuerza abdominal, la resistencia y la capacidad cardiorrespiratoria. Resultados: Los estudiantes de zonas urbanas tenían un 55% (intervalo de confianza del 95% = 1.12-2.12) más de probabilidades de contar con una condición física inadecuada y de residir en una zona inapropiada, en comparación con los estudiantes de zonas rurales. Había una asociación entre la fuerza muscular y la resistencia y la zona de residencia. Estos resultados de la odds ratio demostraron que las posibilidades de los estudiantes que presentaron deficiencias en esta variable fueron 8.99 (intervalo de confianza del 95% = 1.12-72.30) veces mayor entre los escolares de las zonas rurales en comparación con los de zonas urbanas. Se observó que el 25.1% de los adolescentes opinaban que tenían una composición corporal inadecuada y que la proporción de adolescentes con composición corporal inadecuada fue mayor (p < 0.05) en los hombres (32.3%) en comparación con las mujeres (18%). Conclusión: Se concluyó que había una asociación entre los componentes de la condición física relacionada con la salud y el área de residencia en los grupos estudiados


Objetivo: O objetivo deste estudo foi determinar a associação entre aptidão física, fatores socio demográficose prevalência de sobrepeso de escolares adolescentes de cidades urbanas e rurais. Método: A população do estudo foi composta por 377 adolescentes do sexo masculino e feminino, com idade entre 14-17 anos, que foram selecionados aleatoriamente e estudavam em escolas públicas das zonas urbanas e rurais do norte do Brasil. Foram avaliados o nível socioeconômico, flexibilidade, força abdominal, resistência e aptidão cardiorrespiratória. Resultados: Os alunos das zonas urbanas tiveram 55% de probabilidade maior em possuir uma aptidão física inadequada, e residir em uma área inadequada quando comparados com os estudantes da zona rural (intervalo de confiança de 95% = 1.12-2.12). Houve uma associação entre força e resistência muscular com a área de residência. Estes resultados da odds ratio demonstram que as chances de os estudantes apresentarem inadequação nesta variável foram de 8.99 (intervalo de confiança de 95% = 1.12-72.30) vezes maiores entre crianças em idade escolar na zona rural, em comparação com as de zona urbana. Observou-se que 25.1% dos adolescentes encontraram-se com a composição corporal inadequada e esta proporçãofoi maior (p < 0.05) para o sexo masculino (32.3%) em relação ao sexo feminino (18%). Conclusão: Concluiu-se que houve uma associação entre os componentes da aptidão física relacionada com a saúde e área de residência nos grupos estudados no presente estudo


Assuntos
Humanos , Masculino , Feminino , Adolescente , Aptidão Física/fisiologia , Sobrepeso/epidemiologia , Composição Corporal/fisiologia , Força Muscular/fisiologia , Obesidade/epidemiologia , Saúde do Adolescente/estatística & dados numéricos , Antropometria/métodos , Pesos e Medidas Corporais/estatística & dados numéricos , Brasil/epidemiologia , Fatores Socioeconômicos
7.
Med Oncol ; 35(3): 36, 2018 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-29429058

RESUMO

In tumor microenvironment, immunosuppression is a common event and results from the inhibition of activated immune cells and generation of cells with immunosuppressive capacity, as some subtypes of monocytes. The aim of this study was to evaluate the presence of immunosuppressive CD14+/HLA-DRlow/- monocytes in pediatric patients with the diagnosis of B-cell acute lymphoblastic leukemia (B-ALL) and, moreover, verify whether the chemotherapeutic treatment has any effect on these cells. Peripheral blood (PB) and bone marrow (BM) samples were collected from 15 untreated pediatric patients. The presence of CD14+/HLA-DRlow/- monocytes was evaluated at diagnosis and in the end of induction chemotherapy by flow cytometry. CD14+/HLA-DRlow/- monocytes increase was observed in 60% (9/15) of the patients at the end of the induction therapy. We were able to detect an increase in CD14+/HLA-DRlow/- monocytes values in BM and PB samples of pediatric patients with B-ALL. This increase was observed in the end of induction chemotherapy, which leads us to believe that these changes probably could have been induced by the inflammatory process engendered by the cytotoxic treatment or by drugs used in the chemotherapy treatment. This finding may be useful to guide new therapeutic approaches contemplating immunomodulatory drugs that act in the depletion of immunosuppressive monocytes.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Antígenos HLA-DR/metabolismo , Quimioterapia de Indução , Receptores de Lipopolissacarídeos/metabolismo , Monócitos/imunologia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/imunologia , Adolescente , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Terapia de Imunossupressão , Lactente , Masculino , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/metabolismo , Prognóstico , Taxa de Sobrevida
8.
Braz J Biol ; 78(3): 564-573, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29091119

RESUMO

Fire is a recurrent disturbance in savanna vegetation and savanna species are adapted to it. Even so, fire may affect various aspects of plant ecology, including phenology. We studied the effects of a spatially heterogeneous fire on the reproductive phenology of two dominant woody plant species, Miconia albicans (Melastomataceae) and Schefflera vinosa (Araliaceae), in a savanna area in South-eastern Brazil. The study site was partially burnt by a dry-season accidental fire in August 2006, and we monitored the phenolology of 30 burnt and 30 unburnt individuals of each species between September 2007 and September 2008. We used restricted randomizations to assess phenological differences between the burnt and unburnt individuals. Fire had negative effects on the phenology of M. albicans, with a smaller production of reproductive structures in general and of floral buds, total fruits, and ripe fruits in burnt plants. All unburnt but only 16% of the burnt M. albicans plants produced ripe fruits during the study. Fire effects on S. vinosa were smaller, but there was a greater production of floral buds and fruits (but not ripe fruits) by burnt plants; approximately 90% of the individuals of S. vinosa produced ripe fruits during the study, regardless of having been burnt or not. The differences between the two species may be related to S. vinosa's faster growth and absence from the seed bank at the study site, whereas M. albicans grows more slowly and is dominant in the seed bank.


Assuntos
Araliaceae/crescimento & desenvolvimento , Incêndios , Pradaria , Melastomataceae/crescimento & desenvolvimento , Estações do Ano , Araliaceae/anatomia & histologia , Brasil , Melastomataceae/anatomia & histologia
10.
Braz J Med Biol Res ; 50(5): e6019, 2017 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-28423121

RESUMO

Monoclonal B-cell lymphocytosis (MBL) is an asymptomatic clinical entity characterized by the proliferation of monoclonal B cells not meeting the diagnosis criteria for chronic lymphocytic leukemia (CLL). MBL may precede the development of CLL, but the molecular mechanisms responsible for disease progression and evolution are not completely known. Telomeres are usually short in CLL and their attrition may contribute to disease evolution. Here, we determined the telomere lengths of CD5+CD19+ cells in MBL, CLL, and healthy volunteers. Twenty-one CLL patients, 11 subjects with high-count MBL, and 6 with low-count MBL were enrolled. Two hundred and sixty-one healthy volunteers aged 0 to 88 years were studied as controls. After diagnosis confirmation, a flow cytometry CD19+CD5+-based cell sorting was performed for the study groups. Telomere length was determined by qPCR. Telomere length was similar in the 3 study groups but shorter in these groups compared to normal age-matched subjects that had been enrolled in a previous study from our group. These findings suggest that telomere shortening is an early event in CLL leukemogenesis.


Assuntos
Linfócitos B/patologia , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/patologia , Linfocitose/genética , Linfocitose/patologia , Encurtamento do Telômero/genética , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Progressão da Doença , Feminino , Citometria de Fluxo , Marcadores Genéticos , Humanos , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Padrões de Referência , Estatísticas não Paramétricas , Telômero/patologia
11.
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1467095

RESUMO

Abstract Fire is a recurrent disturbance in savanna vegetation and savanna species are adapted to it. Even so, fire may affect various aspects of plant ecology, including phenology. We studied the effects of a spatially heterogeneous fire on the reproductive phenology of two dominant woody plant species, Miconia albicans (Melastomataceae) and Schefflera vinosa (Araliaceae), in a savanna area in South-eastern Brazil. The study site was partially burnt by a dry-season accidental fire in August 2006, and we monitored the phenolology of 30 burnt and 30 unburnt individuals of each species between September 2007 and September 2008. We used restricted randomizations to assess phenological differences between the burnt and unburnt individuals. Fire had negative effects on the phenology of M. albicans, with a smaller production of reproductive structures in general and of floral buds, total fruits, and ripe fruits in burnt plants. All unburnt but only 16% of the burnt M. albicans plants produced ripe fruits during the study. Fire effects on S. vinosa were smaller, but there was a greater production of floral buds and fruits (but not ripe fruits) by burnt plants; approximately 90% of the individuals of S. vinosa produced ripe fruits during the study, regardless of having been burnt or not. The differences between the two species may be related to S. vinosas faster growth and absence from the seed bank at the study site, whereas M. albicans grows more slowly and is dominant in the seed bank.


Resumo O fogo é uma perturbação recorrente em vegetação savânica e as espécies do cerrado são adaptadas a ele. Mesmo assim, o fogo pode afetar aspectos da ecologia vegetal, incluindo a fenologia. Nós estudamos os efeitos de um incêndio espacialmente heterogêneo sobre a fenologia reprodutiva de duas espécies lenhosas dominantes, Miconia albicans (Melastomataceae) e Schefflera vinosa (Araliaceae), em uma área de cerrado no Sudeste do Brasil. A área de estudo foi parcialmente queimada por um incêndio acidental na estação seca (agosto) de 2006. Nós acompanhamos a fenologia reprodutiva de 30 indivíduos queimados e 30 não-queimados de cada espécie, de setembro de 2007 a setembro de 2008, usando aleatorizações restritas para comparar os dois grupos. Em M. albicans, a produção de estruturas reprodutivas como um todo e de botões florais, frutos e frutos maduros foi maior em indivíduos queimados do que nos não-queimados. Todos os indivíduos não-queimados, mas apenas 16% dos queimados, produziram frutos maduros durante o estudo. Já em S. vinosa, a produção de botões florais e de frutos (mas não de frutos maduros) foi maior em indivíduos queimados; aproximadamente 90% dos indivíduos de S. vinosa produziram frutos maduros durante o estudo, independentemente de terem sido queimados ou não. As diferenças entre as duas espécies podem estar relacionadas com o fato de S. vinosa crescer mais rápido e estar ausente do banco de sementes, ao contrário de M. albicans, de crescimento mais lento e dominante no banco de sementes.

12.
Braz J Biol ; 76(1): 256-67, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26871749

RESUMO

The native bracken (Pteridium arachnoideum) often occurs in mono-specific stands in the Brazilian Cerrado, and this dominance can impact on both the above-ground vegetation and soil seed bank. This study investigated how invasion by this species over a 20-year period changed the seed bank and the relationship between the seed bank and litter mass. We extracted soil samples from three replicated invaded and uninvaded sites, and followed seedling emergence for six months. We collected the above-ground biomass and litter of P. arachnoideum in ten 1m2 plots from three invaded sites. There was no difference between invaded and uninvaded areas in seed bank richness, diversity or overall abundance. The most abundant family was the Melastomataceae, followed by the Poaceae. The Melastomataceae was more abundant in uninvaded sites, but the most common species of this family (Tibouchinastenocarpa) was not affected. The grasses were more common in invaded sites in the rainy season and were affected by heterogeneity in the litter layer. The seed bank could play a role in the recovery of these invaded areas, but the presence of weeds and invasive grasses could constrain their use as a management strategy.


Assuntos
Biodiversidade , Plantas , Pteridium/fisiologia , Sementes/fisiologia , Brasil , Estações do Ano , Solo
13.
Braz J Biol ; 76(1): 66-72, 2016 02.
Artigo em Inglês | MEDLINE | ID: mdl-26909625

RESUMO

The introduction of a species may alter ecological processes of native populations, such as pollination and dispersal patterns, leading to changes in population structure. When the introduced and the native species are congeners, interference in pollination can also lead to hybridization. We aimed to understand the ecological aspects of Euterpe oleracea introduction in the Atlantic forest and the possible consequences for the conservation of the native congener Euterpe edulis. We analysed the population structure of palm populations, including hybrids, and observed the interaction with frugivorous birds of both palm species after E. oleracea introduction. We observed that E. edulis had significantly lower density and a smaller number of seedlings when occurring with E. oleracea. Native and introduced Euterpe species shared nine frugivorous bird species. E. oleracea and hybrids had dispersed outside the original planting area. Consequently, the risks of introduction of E. oleracea may mostly be related to the disruption of interactions between E. edulis and frugivorous birds and the spontaneous production of hybrids. Finally, the cultivation of E. oleracea and hybrids in Atlantic rainforest could affect the conservation of the already endangered E. edulis.


Assuntos
Euterpe/fisiologia , Cadeia Alimentar , Hibridização Genética , Dispersão Vegetal , Brasil , Conservação dos Recursos Naturais , Euterpe/genética , Euterpe/crescimento & desenvolvimento , Espécies Introduzidas , Dinâmica Populacional , Floresta Úmida , Especificidade da Espécie
14.
Braz. j. biol ; 76(1): 66-72, Feb. 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-774494

RESUMO

Abstract The introduction of a species may alter ecological processes of native populations, such as pollination and dispersal patterns, leading to changes in population structure. When the introduced and the native species are congeners, interference in pollination can also lead to hybridization. We aimed to understand the ecological aspects of Euterpe oleracea introduction in the Atlantic forest and the possible consequences for the conservation of the native congener Euterpe edulis. We analysed the population structure of palm populations, including hybrids, and observed the interaction with frugivorous birds of both palm species after E. oleracea introduction. We observed that E. edulis had significantly lower density and a smaller number of seedlings when occurring with E. oleracea. Native and introduced Euterpe species shared nine frugivorous bird species. E. oleracea and hybrids had dispersed outside the original planting area. Consequently, the risks of introduction of E. oleracea may mostly be related to the disruption of interactions between E. edulis and frugivorous birds and the spontaneous production of hybrids. Finally, the cultivation of E. oleracea and hybrids in Atlantic rainforest could affect the conservation of the already endangered E. edulis.


Resumo A introdução de uma espécie pode alterar processos ecológicos de populações nativas, tais como padrões de polinização e dispersão, levando a mudanças na estrutura populacional. Quando espécies introduzidas e nativas são congêneres, a interferência na polinização pode levar também à hibridização. Nossos objetivos foram entender os aspectos ecológicos da introdução de Euterpe oleracea na Floresta Atlântica e as possíveis consequências sobre a conservação da congênere nativa Euterpe edulis. Para isso, analisamos a estrutura populacional, incluindo híbridos, e observamos a interação de aves frugívoras com ambas as espécies de palmeira após a introdução de E. oleracea. Observamos que E. edulis apresentou densidade total e número de plântulas menores quando coocorrente com E. oleracea. As palmeiras congenéricas compartilharam nove espécies de aves frugívoras. E. oleracea e híbridos foram dispersos além da área original de plantio. Consequentemente, os riscos da introdução de E. oleracea podem estar principalmente relacionados com o possível deslocamento de interações entre E. edulis e aves frugívoras e com a produção de híbridos. Desta forma, o cultivo de E. oleracea e híbridos podem afetar a conservação da já ameaçada E. edulis.


Assuntos
Euterpe/fisiologia , Cadeia Alimentar , Hibridização Genética , Dispersão Vegetal , Brasil , Conservação dos Recursos Naturais , Euterpe/genética , Euterpe/crescimento & desenvolvimento , Espécies Introduzidas , Dinâmica Populacional , Floresta Úmida , Especificidade da Espécie
15.
Braz. j. biol ; 76(1): 256-267, Feb. 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-774505

RESUMO

Abstract The native bracken (Pteridium arachnoideum) often occurs in mono-specific stands in the Brazilian Cerrado, and this dominance can impact on both the above-ground vegetation and soil seed bank. This study investigated how invasion by this species over a 20-year period changed the seed bank and the relationship between the seed bank and litter mass. We extracted soil samples from three replicated invaded and uninvaded sites, and followed seedling emergence for six months. We collected the above-ground biomass and litter of P. arachnoideum in ten 1m2 plots from three invaded sites. There was no difference between invaded and uninvaded areas in seed bank richness, diversity or overall abundance. The most abundant family was the Melastomataceae, followed by the Poaceae. The Melastomataceae was more abundant in uninvaded sites, but the most common species of this family (Tibouchinastenocarpa) was not affected. The grasses were more common in invaded sites in the rainy season and were affected by heterogeneity in the litter layer. The seed bank could play a role in the recovery of these invaded areas, but the presence of weeds and invasive grasses could constrain their use as a management strategy.


Resumo O samambaião (Pteridium arachnoideum) frequentemente domina áreas de cerrado, e pode alterar tanto a vegetação estabelecida quanto o banco de sementes do solo. Nesse estudo investigamos como áreas de cerrado invadidas por essa espécie a mais de 20 anos alteraram o banco de sementes, e também a relação entre banco de sementes e quantidade de serapilheira. Extraímos amostras de solo em três invadidas e em áreas controle adjacentes, e monitoramos a emergência de plântulas por seis meses. Coletamos a biomassa aérea e a serapilheira de P. arachnoideum em dez parcelas de 1m2 nas áreas invadidas. Ariqueza, diversidade e abundância totalnão diferiram entre áreas invadidas e controle. A família mais abundante foi Melastomataceae, seguida por Poaceae. Melastomataceae foi mais comum em áreas controle, mas não a espécie mais comum nessa família (Tibouchina stenocarpa). Gramíneas foram predominantes em áreas invadidas durante a estação chuvosa, e foram afetadas pela heterogeneidade da camada de serapilheira. O banco de sementes pode ser importante para a recuperação dessas áreas invadidas, mas esse uso pode ser prejudicado pela presença de ervas daninhas e gramíneas invasoras.


Assuntos
Biodiversidade , Plantas , Pteridium/fisiologia , Sementes/fisiologia , Brasil , Estações do Ano , Solo
17.
Genet Mol Res ; 14(4): 17384-90, 2015 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-26782379

RESUMO

Despite the benefits of crop rotation, occurrence of nematodes is a common problem for almost all crops within the Cerrado biome, especially for rice. The use of resistant cultivars is one of the main methods for control of nematodes. Thus, the present study aimed to evaluate the reaction of 36 upland-rice lines, with desirable agronomic characteristics, according to their resistance to root-knot nematodes (Meloidogyne incognita). The experimental design was entirely randomized with four replications. Each plot of land consisted of two rice plants in a 3-L vase. The plants were inoculated with 1000 eggs and eventual juveniles of the respective nematodes. Fifty-five days after the inoculation, the roots and the aerial part of the plant were weighed and the egg mass (EM) as well as the reproduction factor (Rf) were estimated. It was determined that the isolated use of EM was not beneficial in selecting rice lines resistant to the root-knot nematode. This procedure must, therefore, take into account the egg counting and the Rf, in order to improve the reliability of the selection. In our study, 30 evaluated lines were observed to be resistant. Among the recommended cultivars, only BRS Monarca had its performance susceptible to the studied nematode species.


Assuntos
Resistência à Doença , Oryza/parasitologia , Doenças das Plantas/parasitologia , Tylenchoidea/patogenicidade , Animais , Produtos Agrícolas , Interações Hospedeiro-Parasita/fisiologia , Oryza/crescimento & desenvolvimento , Doenças das Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento
18.
Rev. bras. plantas med ; 17(4,supl.2): 857-864, 2015. tab, graf
Artigo em Português | LILACS | ID: lil-771168

RESUMO

RESUMO Neste estudo, uma técnica de cromatografia líquida de alta resolução em fase reversa (CLAE-FR) para a determinação de ácido rosmarínico em Cordia verbenacea foi desenvolvida e validada. A análise de regressão foi avaliada, com observação de uma boa linearidade (r = 0,9997). Os valores obtidos para a precisão e exatidão estão de acordo com as diretrizes do ICH e com a legislação brasileira. Os valores de repetibilidade e precisão intermediária foram 2,79% e 4,76%, respectivamente. Os limites de detecção e de quantificação de ácido rosmarínico foram de 1,92 µg/mL e 5,81 µg/mL, respectivamente. Os resultados mostraram que o método desenvolvido é uma técnica por CLAE-FR de confiança para a determinação de ácido rosmarínico em tintura de C. verbenacea. Além disso, essa metodologia foi aplicada em estudo sazonal, que revela uma correlação positiva relativamente forte entre o período de chuvas e o teor de ácido rosmarínico.


ABSTRACT In this study, a reverse phase-high performance liquid chromatography (RP-HPLC) technique for determination of rosmarinic acid in the Cordia verbenacea was developed and validated. A regression analysis was performed, with the observation of good linearity (r =0.999949). The values obtained for precision and accuracy determination are in agreement with ICH guidelines and the Brazilian legislation. The values of repeatability and intermediate precision were 2.79% and 4.76%, respectively. The detection and the quantitation limits of the rosmarinic acid were 1.92 µg/mL and 5.81 µg/mL, respectively. The results demonstrated that the developed method is a reliable RP-HPLC technique for the determination of rosmarinic acid in C. verbenacea tincture. In addition, this methodology was applied at a seasonal study indicating relatively strong positive correlation between the rain period and the rosmarinic acid content.


Assuntos
Cromatografia Líquida/métodos , Cordia/classificação , Plantas Medicinais/classificação , Estações do Ano
19.
Oncogenesis ; 3: e123, 2014 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-25329722

RESUMO

The tumor microenvironment has a dynamic and usually cancer-promoting function during all tumorigenic steps. Glioblastoma (GBM) is a fatal tumor of the central nervous system, in which a substantial number of non-tumoral infiltrated cells can be found. Astrocytes neighboring these tumor cells have a particular reactive phenotype and can enhance GBM malignancy by inducing aberrant cell proliferation and invasion. The tumor suppressor p53 has a potential non-cell autonomous function by modulating the expression of secreted proteins that influence neighbor cells. In this work, we investigated the role of p53 on the crosstalk between GBM cells and astrocytes. We show that extracellular matrix (ECM) from p53(+/-) astrocytes is richer in laminin and fibronectin, compared with ECM from p53(+/+) astrocytes. In addition, ECM from p53(+/-) astrocytes increases the survival and the expression of mesenchymal markers in GBM cells, which suggests haploinsufficient phenotype of the p53(+/-) microenvironment. Importantly, conditioned medium from GBM cells blocks the expression of p53 in p53(+/+) astrocytes, even when DNA was damaged. These results suggest that GBM cells create a dysfunctional microenvironment based on the impairment of p53 expression that in turns exacerbates tumor endurance.

20.
Braz J Biol ; 74(1): 156-65, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25055097

RESUMO

Pteridium is a cosmopolitan genus that acts as an invasive species in many parts of the world. Most research on this genus has occurred in Europe, and there is a lack of data on it from South America, in spite of causing considerable conservation problems. We compared the biomass allocation of P. esculentum subsp. arachnoideum in two ecosystems in Brazil - Atlantic forest and Brazilian savanna. We measured the biomass of fronds, rhizomes and above-ground litter. We also compared the density, length and biomass of fronds from this Brazilian study with similar data of P. esculentum subsp. arachnoideum derived from Venezuela and P. aquilinum from Europe. P. esculentum subsp. arachnoideum showed a wide response range. We found a negative relationship between frond and necromass, indicating a negative feedback effect, while a positive relationship was observed between frond and rhizome biomass. The continental comparison of relationships showed that Pteridium responds in a different way in both Brazil and Europe, and that in Brazil fronds tend to be longer and heavier, presumably as a result of the continuous growing season in South America while is shortened in Europe by frost. The paper shows the ability of Pteridium to adapt to different ecosystems.


Assuntos
Biomassa , Pteridium/fisiologia , Brasil , Ecossistema , Europa (Continente) , Estações do Ano
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