Glutathione Reductase (GR) plays a key role in the maintenance of GSH homeostasis, variations in its activity may indicate damage from environmental contaminants. Experimental planning is a strategy to reduces time and cost in enzymatic assays. In this work, DCCR experimental planning was used to standardize and to validate the measure of GR in Aegla singularis bioindicator. Samples of A. singularis were collected in three watersheds with different percentages of naturalness and land uses. At all, were selected 7 streams, in which collections were performed at one upstream (most preserved) and one downstream (less preserved) point. Effects of temperature, reading time, substrate (GSSG) and protein concentration in GR reaction medium were evaluated, being that the two latter variables were optimized by DCCR. GR was not affected by temperature (15 to 30 °C) or reading time (6 and 10 minutes). Increased concentrations of proteins from biological extract had negative correlation with GR, whereas higher concentrations of GSSG resulted in higher GR activity. Environmental validation showed that GR in Aeglawas influenced primarily by the watershed of origin. DCCR planning was efficient to optimizing the use of GR as a biomarker of environmental quality.

Abstract The subtropical riverine forests present a variation in soil water availability throughout the year, following precipitation seasonality. The objective of this work was to evaluate the responses of Cordia americana to different light intensities combined with soil flooding. Seedlings were acclimated to light treatments, with full sun and shade conditions. Sun and shade plants were subjected to soil flooding during periods of 10 (short) and 30 (longer) days. After 10 days, flooded plants had a higher root dry mass accumulation and soluble sugars content, regardless of the light condition. Shade plants presented higher shoot soluble sugars content in relation to the sun plants. After 30 days, a higher shoot soluble sugar content was observed in sun and shade flooded plants. In addition, a higher root soluble sugar content was also observed in sun plants under flood. Periods of short flooding, characterized in subtropical forests as from 5 to 15 days, favor the growth of shade plants and the roots sugar accumulation, fact that can explain the species distribution. However, long periods of flooding may be associated with light environment plasticity, suggesting that the sun plants present a higher flooding tolerance, directly associated with the ability to maintain the sugar content.

This study reports the optimization of geranyl butanoate production by esterification of geraniol and butanoic acid in a solvent-free system using two immobilized lipases as catalyst. The operating conditions that optimized geranyl butanoate production were determined to be 40 °C, a geraniol to butanoic acid molar ratio of 3:1, 150 rpm, 5 wt% of enzyme, and 1 h of reaction, which resulted in a reaction conversion of about 97% for Novozyme 435. When homemade Novozyme NZL-102-LYO-HQ (Cal-B) immobilized in polyurethane foam was used as catalyst, the experimental conditions of an alcohol to acid molar ratio of 5:1, 70 °C, 150 rpm, 5 wt% of enzyme, and 1 h of reaction gave a conversion of 95%. New experimental data on enzymatic esterification of geraniol and butanoic acid for geranyl butanoate production are reported in this work, showing that the technique is promising for overcoming the well-known drawbacks of the chemical-catalyzed route.

ABSTRACT Streams in urban areas are strongly impacted by the input of organic matter and metals, for instance copper (Cu) and zinc (Zn). These metals are essential for the aquatic biota, but when absorbed in excess they are toxic. In Chiro nomidae larvae, the deleterious effects of heavy metals can be ascertained by analyzing the morphological deformities of the larval mentum, a structure of the oral cavity. In this study, we evaluated I) the bioavailability of Cu and Zn in urban stream sediments and II) the relationship between Cu and Zn concentrations and the incidence of deformities in the mentum of Chironomus larvae. Chironomid flies were collected from four locations in two streams at an urban area in southern Brazil. They were identified and the incidence of deformities in the mentum was quantified. Sediment samples were collected at the same locations where larvae were collected, to quantify the bioavailable fractions of Cu and Zn. The concentrations of Cu in the sediment were similar between the collection sites. However, Zn concentrations varied among sites, being greater in the stretch directly influenced by the input of the organic waste. In total, 2,895 Chironomid larvae were collected. The incidence of deformities in the mentum was above 30% and was correlated with the concentrations of Cu (r = 0.68) and Zn (r = 0.87). This correlation indicates that the municipal waste that is thrown into the city’s streams has influenced the occurrence of deformities.