Universidade Federal de Santa Maria

About: Universidade Federal de Santa Maria is a education organization based out in Santa Maria, Brazil. It is known for research contribution in the topics: Population & Context (language use). The organization has 21178 authors who have published 35632 publications receiving 371665 citations.

Oxidative Stress in Methylmercury-Induced Cell Toxicity

Abstract: Methylmercury (MeHg) is a hazardous environmental pollutant, which elicits significant toxicity in humans. The accumulation of MeHg through the daily consumption of large predatory fish poses potential health risks, and the central nervous system (CNS) is the primary target of toxicity. Despite well-described neurobehavioral effects (i.e., motor impairment), the mechanisms of MeHg-induced toxicity are not completely understood. However, several lines of evidence point out the oxidative stress as an important molecular mechanism in MeHg-induced intoxication. Indeed, MeHg is a soft electrophile that preferentially interacts with nucleophilic groups (mainly thiols and selenols) from proteins and low-molecular-weight molecules. Such interaction contributes to the occurrence of oxidative stress, which can produce damage by several interacting mechanisms, impairing the function of various molecules (i.e., proteins, lipids, and nucleic acids), potentially resulting in modulation of different cellular signal transduction pathways. This review summarizes the general aspects regarding the interaction between MeHg with regulators of the antioxidant response system that are rich in thiol and selenol groups such as glutathione (GSH), and the selenoenzymes thioredoxin reductase (TrxR) and glutathione peroxidase (Gpx). A particular attention is directed towards the role of the PI3K/Akt signaling pathway and the nuclear transcription factor NF-E2-related factor 2 (Nrf2) in MeHg-induced redox imbalance.

Forms of inorganic phosphorus in soil under different long term soil tillage systems and winter crops

Abstract: The cultivation of crops with different capacity of P uptake and use under long-term soil tillage systems can affect the distribution of P cycling and inorganic forms in the soil, as a result of higher or lower use efficiency of P applied in fertilizers. The purpose of this study was to evaluate the effect of long-term cultivation of different winter species under tillage systems on the distribution of inorganic P forms in the soil. In 1986, the experiment was initiated with six winter crops (blue lupin, hairy vetch, oat, oilseed radish, wheat and fallow) on a Rhodic Hapludox in southwestern Parana, under no-tillage (NT) and conventional tillage (CT). The application of phosphate fertilizer in NT rows increased inorganic P in the labile and moderately labile forms, and soil disturbance in CT redistributed the applied P in the deeper layers, increasing the moderately labile P concentration in the subsurface layers. Black oat and blue lupin were the most efficient P-recyclers and under NT, they increased the labile P content in the soil surface layers.

Produção e decomposição de fitomassa de plantas invernais de cobertura de solo e milho, sob diferentes manejos da adubação nitrogenada winter cover crops and corn biomass production and decomposition, under different nitrogen fertilization managements

Abstract: Mestrando do Programa de Pos-graduacao em Agronomia, UFSM.RESUMOA qualidade do residuo vegetal e a disponibilidadede nitrogenio (N) mineral sao fatores que afetam adecomposicao de residuos vegetais. O presente trabalho teve porobjetivo avaliar a producao de materia seca, o acumulo denitrogenio de tres plantas para cobertura de solo no inverno e ainfluencia de diferentes epocas de aplicacao da adubacaonitrogenada na cultura do milho sobre a decomposicao doresiduo vegetal mantido na superficie. O experimento foidesenvolvido na Universidade Federal de Santa Maria (RS), nosanos agricolas de 1996/97 e 1997/98, em solo ARGISSOLOVERMELHO Distrofico arenico (Hapludalf), sendo que aavaliacao da taxa de decomposicao do residuo superficial foifeita somente no ano agricola de 1997/98. O delineamentoexperimental foi de blocos ao acaso com parcelas subdivididas etres repeticoes. Nas parcelas principais (25 x 5m), durante oinverno foram utilizadas tres coberturas de solo: aveia preta(Avena strigosa Schieb), aveia+ervilhaca ( Vicia sativa L.) e naboforrageiro (Raphanus sativus). Nas subparcelas (5 x 5m),diferentes epocas de aplicacao de N no milho: (i)00-00-00,(ii)00-30-90, (iii)30-30-60, (iv)60-30-30 e (v)90-30-00, quecorresponde a quantidade de N em kg ha

Hydrogel containing dexamethasone-loaded nanocapsules for cutaneous administration: preparation, characterization, and in vitro drug release study.

Abstract: Context: Our group previously reported the development of dexamethasone-loaded polymeric nanocapsules as an alternative for topical dermatological treatments. Objective: Our study aimed to prepare and characterize a hydrogel containing this system to improve the effectiveness of the glucocorticoid for cutaneous disorders. Methods: For the antiproliferative activity assay, a dexamethasone solution and D-NC were tested on Allium cepa root meristem model. D-NC were prepared by the interfacial deposition of preformed polymer. Hydrogels were prepared using Carbopol Ultrez® 10 NF, as polymer, and characterized according to the following characteristics: pH, drug content, spreadability, viscosity, and in vitro drug release. Results and Discussion: Nanocapsules showed mean particle size and zeta potential of 201 ± 6 and −5.73 ± 0.42 nm, respectively. They demonstrated a lower mitotic index (4.62%) compared to free dexamethasone (8.60%). Semisolid formulations presented acidic pH values and adequate drug content (...

Benefits of using the probiotic Efinol®L during transportation of cardinal tetra, Paracheirodon axelrodi (Schultz), in the Amazon.

Abstract: The objective of this experiment was to test the probiotic Efinol®L during transportation of cardinal tetra, Paracheirodon axelrodi (Schultz). For the transportation, fish were distributed in 18 plastic tanks, of which nine contained the Efinol®L (10 mg L−1; probiotic treatment) and the remaining had no probiotic (control treatment). Transport lasted 24 h and three different boxes of each treatment were sampled at 3, 12 and 24 h. Up to the 12-h sampling period, no significant difference in the survival was observed; on the other hand, survival was higher at the end of the transport (24 h) in the probiotic treatment. No significant difference was found in dissolved oxygen and temperature between treatments. Conductivity, pH and alkalinity increased along the transport, but without a difference between treatments. Ammonia increased in all treatments, although it was significantly lower in the probiotic group at 24 h. Cortisol levels were significantly higher in all transported fish when compared with the basal values. At 24 h, cortisol levels in control fish were significantly higher than those in the probiotic treatment. With the observed results, we are able to conclude that the probiotic Efinol®L is efficient during cardinal transport, lowering the mortality and helping maintain water quality possibly by lowering metabolic wastes.