Effect of mitochondrial potassium channel on the renal protection mediated by sodium thiosulfate against ethylene glycol induced nephrolithiasis in rat model

Purpose: Sodium thiosulfate (STS) is clinically reported to be a promising drug in preventing nephrolithiasis. However, its mechanism of action remains unclear. In the present study, we investigated the role of mitochondrial KATP channel in the renal protection mediated by STS. Materials and Methods: Nephrolithiasis was induced in Wistar rats by administrating 0.4% ethylene glycol (EG) along with 1% ammonium chloride for one week in drinking water followed by only 0.75% EG for two weeks. Treatment groups received STS, mitochondrial KATP channel opener and closer exclusively or in combination with STS for two weeks. Results: Animals treated with STS showed normal renal tissue architecture, supported by near normal serum creatinine, urea and ALP activity. Diazoxide (mitochondria KATP channel opening) treatment to the animal also showed normal renal tissue histology and improved serum chemistry. However, an opposite result was shown by glibenclamide (mitochondria KATP channel closer) treated rats. STS administered along with diazoxide negated the renal protection rendered by diazoxide alone, while it imparted protection to the glibenclamide treated rats, formulating a mitochondria modulated STS action. Conclusion: The present study confirmed that STS render renal protection not only through chelation and antioxidant effect but also by modulating the mitochondrial KATP channel for preventing urolithiasis.

Estudo da produção de biomassa e lipídios no cultivo de Neochloris oleoabundans sob diferentes condições de estresse nutricional e físico / Investigation on biomass and lipids accumulation in Neochloris oleoabundans cultivation under different nutritional and phisical stress conditions

As microalgas são candidatas promissoras para a produção em larga escala de biocombustíveis devido a sua alta eficiência fotossintética. No entanto, os custos relativamente altos de produção por baixas produtividades em lipídios têm sido um dos principais obstáculos que impedem sua produção comercial. Portanto, é necessário focar a pesquisa no aumento da biomassa e na produtividade em lipídios, através do desenvolvimento de biorreatores e técnicas de cultivo inovadoras. Numa primeira fase, este estudo mostra a otimização dos regimes de adição de nutrientes no cultivo de Neochloris oleoabundans em fotobiorreatores tubulares, determinando que a melhor metodologia de adição de CO2 é adicionando-o de forma intermitente e automatizada, enquanto que o melhor processo de alimentação de nitrogênio é por meio de um processo em batelada alimentada tomando como uma referência a produtividade diária de biomassa. Na segunda etapa, foi testada a influência de agentes estressores adicionados ao cultivo sob carência de nitrogênio, tais como tiossulfato de sódio como agente redutor e cloreto de sódio e glicerina como agentes de choque osmótico, buscando um acúmulo de lipídios na biomassa. Os resultados mostraram que o tiossulfato de sódio em 1,2 mM e o cloreto de sódio em 2,2 mM aumentaram o total de lipídios em 21% e 25%, respectivamente. Finalmente, foram testados diferentes regimes de luz, com um esquema 12:12, sendo 12 horas de luz fluorescente e 12 horas com um sistema distinto: escuro, diodos emissores de luz (LED) vermelha e LED branca. Os melhores resultados foram obtidos com LED branca, com um acúmulo de lipídios de até 27% da biomassa seca e uma concentração final de células de 2335mg/L, estabelecendo assim um método de iluminação econômica com alta produtividade (145mg / L dia)

Microalgae are promising candidates for large-scale global biofuel production because of their high photosynthetic efficiency. However, relatively high production costs due to low lipid productivity have been one of the major obstacles impeding their commercial production. Therefore, it is necessary to accurate the research into an increase in biomass and oil productivity, by means of novel bioreactors' design and cultivation techniques. On a first stage, this study shows the optimization of nutrients' addition regimes in Neochloris oleoabundans cultivation in tubular photobioreactors, finding that the best CO2 addition methodology is an automatized intermittent adding and the best feeding process for nitrogen is a fed-batch process taking as a reference the daily biomass productivity. On the second step, it was tested the influence of stressing agents added to the culture under nitrogen starvation, such as sodium thiosulphate for reducing environment and sodium chloride and glycerol for osmotic shock, aiming lipid accumulation in the biomass. The results showed that sodium thiosulphate at 1,2mM and sodium chloride at 2,2mM raised the total lipids up to 21% and 25% respectively. Finally, there were tested different light regimes, with a scheme 12:12, being 12 hours of fluorescent light and 12 hours of a singular system: dark, red light-emitting-diodes (LED) and white LED. The best results were obtained with white LED, with an accumulation up to 27% of dry biomass and a final cell concentration up to 2335mg/L, establishing an economic illumination method with high productivity

Alternative control of Tetranychus evansi Baker & Pritchard (Acari: Tetranychidae) on tomato plants grown in greenhouses

Tetranychus evansi Baker & Pritchard is an important pest of solanaceous plants, including tomatoes. This mite is characterized by a high reproductive rate, which leads to high population growth in a short period of time causing important economic damage. Control of T. evansi is mainly through synthetic acaricides. In searching for environmentally friendly control measures, we evaluated the efficiency of alternative products to control T. evansi on tomato plants under greenhouse conditions. The products tested were lime sulphur and neem based products. We first estimated the lethal concentration (LC) and instantaneous rate of increase (r i) of T. evansi exposed to different product concentrations in laboratory conditions, and later tested the efficacy of LC95 and the concentrations that restrained mite population growth (r i = 0) in greenhouse conditions. The following treatments were repeated three times: NeemPro (81.0 and 71.6 mg a.i./l), Natuneem (31.1 and 20.4 mg ai/l), Organic Neem (39.1 and 30.4 mg a.i./l), lime sulphur (1.0 and 0.6 percent) and water (control). For all products, control provided by LC95 was higher than provided for lower concentrations (r i = 0) one day after spraying. However, after five days, for both concentrations, the percentage of T. evansi population reduction was superior to 95 percent and increased over time. Only plants sprayed with Natuneem (31.1 mg a.i./l) showed symptoms of phytotoxicity. Lime sulphur and neem based products, applied in appropriate concentrations and formulations, bear out as a viable alternative to control T. evansi on tomato plants.