https://www.alice.cnptia.embrapa.br/alice/handle/item/133 Artigo em periódico indexado (CPAC) Wed, 27 May 2026 18:02:31 GMT 2026-05-27T18:02:31Z https://www.alice.cnptia.embrapa.br/alice/handle/doc/1186689 Título: The impact of melatonin on cellular dynamics and gene expression of bovine embryos cultured under low and high oxygen tension. Autoria: OLIVEIRA, I. R. dos S.; MARTINS, C. F.; RODRIGUES, F. L.; MELLO, V. C.; RODRIGUES, M. T. de O.; FARIA, L. C. de; AMARAL, H. B. S.; ANDRADE, R. V. de; FONSECA, M. J. P.; DODE, M. A. N.; BÁO, S. N. Conteúdo: This study investigated the effects of melatonin supplementation in the culture medium on the development, cellular dynamics and gene expression of bovine embryos produced in vitro under low (5%) or high (20%) oxygen tension. Zygotes were cultured without melatonin or with (10−9 M), and cleavage, blastocyst rates, blastomere number, apoptosis, mitochondrial activity, lipid accumulation, and expression of genes related to metabolism, oxidative stress and embryo quality were evaluated. Under high O₂ tension, melatonin increased blastocyst rate (39.8% vs. 34.0%), raised blastomere number, reduced apoptosis, and decreased lipid accumulation. It also upregulated SOD2, KRT8, IFN-τ, and PLAC8. Under low O₂ tension, melatonin increased cleavage rate and mitochondrial activity but did not affect blastocyst rate; only SOD2 was upregulated. Embryos cultured without melatonin under low O₂ showed higher IFN-τ and PLAC8 expression. In conclusion, melatonin improves embryo quality and viability mainly under high oxygen tension, acting as an antioxidant, gene modulator and apoptosis inhibitor. Its effects are more limited under low O2, likely because this environment is closer to physiological conditions and requires fewer responses to oxidative stress. Thu, 01 Jan 2026 00:00:00 GMT https://www.alice.cnptia.embrapa.br/alice/handle/doc/1186689 2026-01-01T00:00:00Z https://www.alice.cnptia.embrapa.br/alice/handle/doc/1186503 Título: Hyperdominant trees reveal savanna vulnerability under climate change. Autoria: ALVAREZ, F.; MARIMON-JUNIOR, B. H.; MARIMON, B. S.; CRUZ, W. J. A. da; RIBEIRO JÚNIOR, N. B.; BÉU, R. G.; BISPO, P. da C.; MEDEIROS, A. de S.; SIQUEIRA, G. M.; BUENO, M. L.; AQUINO, F. de G.; GUILHERME, F. A. G.; PINTO, J. R. R.; MEWS, H. A.; WALTER, B. M. T.; MIRANDA, S. do C. de; HAIDAR, R. F.; OLIVEIRA, E. L. de; BRANDÃO, R. D. F.; MATRICARDI, E. A. T.; MUNHOZ, C. B. R.; LIMA, E. de S.; CARNIELLO, M. A.; BUSTAMANTE, M. M. da C.; MORANDI, P. S.; OLIVEIRA, E. A. de; FINGER, Z.; NEVES, E. C. das; ELIAS, F.; MENOR, I. O.; REIS, S. M. de A.; PHILLIPS, O.; FELDPAUSCH, T. R. Conteúdo: Abstract: The Cerrado biome, spanning ~2 million km2, is one of the most extensive and biodiverse tropical savannas, yet it is paradoxically dominated by only 30 hyperdominant tree species (~2% of all species, > 50% of all stems). However, their vulnerability to climate change and the effectiveness of current conservation efforts remain uncertain. By combining (i) species distribution models calibrated with edaphic-climatic predictors and occurrence data for hyperdominant Cerrado trees with (ii) functional-trait analyses related to ecological strategies (leaf economics, bark investment, ecophysiology, drought tolerance, regeneration, and dispersal), we identified the biomass production and reproductive traits that best predict species persistence under high-emission scenarios (RCP8.5). Currently, only 427,980 km2 (~17.4%) of the modeled potential environmental suitability falls within protected areas; under future climate scenarios, this protected suitable area is projected to decline by ~45.9% to 231,377 km2 (~18.1%). This loss, resulting from land conversion with the expansion of agricultural frontiers and fire events, highlights a mismatch in current regional conservation priorities, overlooking the needs of the Cerrado and its associated biodiversity. Given ongoing land-use change and that 58% of remaining native vegetation occurs on private lands, this mismatch highlights the urgent need to align conservation and agricultural policy. Functional trait analyses revealed a clear gradient from acquisitive “fast” to conservative “slow” strategies, reflecting trade-offs in water-use efficiency and biomass allocation, with leaf structural and reproductive traits best predicting species resilience to climate change. Our results indicate that a small subset of hyperdominant species not only forms current community structure but also signals the biome's resilience/vulnerability to climate change. Conservation planning should prioritize identified climate refuges and be based on functional traits to buffer the loss of functional and structural integrity in one of the world's richest and most threatened savanna ecosystems. Thu, 01 Jan 2026 00:00:00 GMT https://www.alice.cnptia.embrapa.br/alice/handle/doc/1186503 2026-01-01T00:00:00Z https://www.alice.cnptia.embrapa.br/alice/handle/doc/1186538 Título: Assessing soil health in family farming systems using a four-quadrant model based on β-Glucosidase, arylsulfatase and organic carbon. Autoria: FIGUEIREDO, J. P.; MENDES, I. de C.; MIOLA, E. C. C.; GUATIMOSIM, E.; FARIAS, E.; HAUDT, I.; BURGUEÑO, L. E. T.; ISLABÃO, G. O.; LEAL, O. dos A.; STUMPF, L. Conteúdo: The four-quadrant model integrating soil β-glucosidase and arylsulfatase enzyme activity with organic carbon has been recently proposed as a framework to assess agricultural soil health status. Nevertheless, soil enzyme activity responses to contrasting family farming practices remain poorly understood. We evaluated β-glucosidase and arylsulfatase enzyme activity in response to conventional and agroecological family farming practices and their relationship with biological and soil fertility attributes. Four Brazilian family-based farms including horticultural and crop systems with 3–15 years of existence were studied. Soil samples were collected from the 0.00–0.10 m layer for analysis of soil β-glucosidase and arylsulfatase enzyme activities, microbial biomass carbon, basal respiration, mites and springtails abundance, pH, exchangeable calcium and magnesium, available potassium and phosphorus, and soil organic matter content. Enzyme activity, mite abundance and soil organic matter content tended to be higher in forest soil (reference). The four-quadrant model differentiated agroecological from conventional systems, with agroecological systems, particularly those combining organic inputs and soil cover, showing patterns consistent with improvement in soil health. Principal component analysis revealed similar relationships among soil attributes. These patterns may be associated with management practices such as organic fertilization, cover cropping, reduced mechanical soil disturbance, and crop rotation, which together enhance organic matter levels and stimulate microbial activity. However, longer-term or more intensive management may be required to reach the highest soil health category. The results indicate that the four-quadrant model may be a useful framework for interpreting changes in soil health under family farming systems. Soil organic matter, basal respiration, and enzymatic activity were the attributes most closely associated with soil biological functioning and may serve to diagnose and monitor soil health in family-based farming systems. Thu, 01 Jan 2026 00:00:00 GMT https://www.alice.cnptia.embrapa.br/alice/handle/doc/1186538 2026-01-01T00:00:00Z https://www.alice.cnptia.embrapa.br/alice/handle/doc/1186467 Título: Estimativa da variação na demanda de água para irrigação por pivô-central no Distrito Federal entre 1992 e 2002. Autoria: SANO, E. E.; LIMA, J. E. F. W.; SILVA, E. M. D.; OLIVEIRA, E. C. Conteúdo: O aumento da demanda de água para a irrigação tem sido objeto de constante preocupação dos órgãos de gestão dos recursos hídricos e da população do Distrito Federal. Os objetivos deste trabalho foram determinar a variação da área irrigada por pivôs-centrais no Distrito Federal entre os anos de 1992 e 2002, estimar a demanda hídrica desses sistemas, bem como verificar sua importância em relação ao consumo humano. Utilizando imagens de satélite e ferramentas de geoprocessamento, foram determinadas as áreas irrigadas por pivô-central. O consumo de água dessas áreas irrigadas foi estimado com base em dados da literatura referentes às principais culturas semeadas na região. Entre 1992 e 2002, o número de pivôs-centrais no Distrito Federal passou de 55 para 104, a área irrigada de 3.894 ha para 6.823 ha e o consumo, de 23,36 para 40,94 milhões de m3 ano-1. O consumo de água para irrigação por pivô-central no Distrito Federal é, ainda, menos representativo do que o consumo de água para o abastecimento humano; entretanto, a demanda para a irrigação tem crescido de forma mais acelerada, indicando tendência de alteração desse quadro. Sat, 01 Jan 2005 00:00:00 GMT https://www.alice.cnptia.embrapa.br/alice/handle/doc/1186467 2005-01-01T00:00:00Z