Innovative development of membrane sparger for carbon dioxide supply in microalgae cultures

The present study was aimed to develop a membrane sparger (MS) integrated into a tubular photobioreactor to promote the increase of the carbon dioxide (CO₂) fixation by Spirulina sp. LEB 18 cultures. The use of MS for the CO₂ supply in Spirulina cultures resulted not only in the increase of DIC concentrations but also in the highest accumulated DIC concentration in the liquid medium (127.4 mg L⁻¹ d⁻¹). The highest values of biomass concentration (1.98 g L⁻¹), biomass productivity (131.8 mg L⁻¹ d⁻¹), carbon in biomass (47.9% w w⁻¹), CO₂ fixation rate (231.6 mg L⁻¹ d⁻¹), and CO₂ use efficiency (80.5% w w⁻¹) by Spirulina were verified with MS, compared to the culture with conventional sparger for CO₂ supply. Spirulina biomass in both culture conditions had high protein contents varying from 64.9 to 69% (w w⁻¹). MS can be considered an innovative system for the supply of carbon for the microalgae cultivation and biomass production. Moreover, the use of membrane system might contribute to increased process efficiency with a reduced cost of biomass production.     

Correction to: Determining ecosystem functioning in Brazilian biomes through foliar carbon and nitrogen concentrations and stable isotope ratios

Biogeochemistry - The initial online publication contained typesetting mistakes in the author information. The original article has been corrected.     

Feeding behavior and trophic niche partitioning between co-existing river otter species

Niche partitioning occurs among coexisting populations to reduce the effects of competitive exclusion among species of similar niche. The aim of the present study is to verify the trophic niche partitioning and feeding behavior between two mustelids, the Giant otter and the Neotropical otter, through the dry and rainy season hydrologic of the Lower Xingu River. Our results suggest that the diets of both mustelids are composed primarily of fish of the family Anostomidae (Headstanders). Despite extensive niche overlap, our results indicate partitioning is facilitated by differences in niche breadth, with potential implications for conservation of both species in the case of declines in prey abundance and diversity. Both species inhabit an area recently impacted by completion of the Belo Monte Hydropower Plant, resulting in large changes to the hydrologic regime. Thus, our results provide important information for conservation efforts regarding the feeding behavior and co-occurrence of both species, as well as providing a baseline for monitoring future health of these mustelid populations. The present study is the first to test the hypothesis of niche partitioning between these two mustelids outside a protected area in the Amazon.

     

Aerobic training prevents cardiometabolic changes triggered by myocardial infarction in ovariectomized rats

This study aimed to evaluate the impact of aerobic training (AT) on autonomic, cardiometabolic, ubiquitin‐proteasome activity, and inflammatory changes evoked by myocardial infarction (MI) in ovariectomized rats. Female Wistar rats were ovariectomized and divided into four groups: sedentary + sham (SS), sedentary + MI (SI), AT + sham surgery (TS), AT + MI (TI). AT was performed on a treadmill for 8 weeks before MI. Infarcted rats previously subjected to AT presented improved physical capacity, increased interleukin‐10, and decreased pro‐inflammatory cytokines. Metabolomic analysis identified and quantified 62 metabolites, 9 were considered significant by the Vip Score. SS, SI, and TS groups presented distinct metabolic profiles; however, TI could not be distinguished from the SS group. MI dramatically increased levels of dimethylamine, and AT prevented this response. Our findings suggest that AT may be useful in preventing the negative changes in functional, inflammatory, and metabolic parameters related to MI in ovariectomized rats.     

Cardamonin Presents in Vivo Activity against Schistosoma mansoni and Inhibits Potato Apyrase

Schistosomiasis, a neglected tropical disease caused by Schistosoma species, harms over 250 million people in several countries. The treatment is achieved with only one drug, praziquantel. Cardamonin, a natural chalcone with in vitro schistosomicidal activity, has not been in vivo evaluated against Schistosoma. In this work, we evaluated the in vivo schistosomicidal activities of cardamonin against Schistosoma mansoni worms and conducted enzymatic apyrase inhibition assay, as well as molecular docking analysis of cardamonin against potato apyrase, S. mansoni NTPDase 1 and S. mansoni NTPDase 2. In a mouse model of schistosomiasis, the oral treatment with cardamonin (400 mg/kg) showed efficacy against S. mansoni, decreasing the total worm load in 46.8 % and reducing in 54.5 % the number of eggs in mice. Cardamonin achieved a significant inhibition of the apyrase activity and the three-dimensional structure of the potato apyrase, obtained by homology modeling, showed that cardamonin may interact mainly through hydrogen bonds. Molecular docking studies corroborate with the action of cardamonin in binding and inhibiting both potato apyrase and S. mansoni NTPDases.     

Synthetic Aurones: New Features for Schistosoma mansoni Therapy

In this work, two synthetic aurones revealed moderate schistosomicidal potential in in vitro and in vivo assays. Aurones ( 1 ) and ( 2 ) promoted changes in tegument integrity and motor activity, leading to death of adult Schistosoma mansoni worms in in vitro assays. When administered orally (two doses of 50 mg/kg) in experimentally infected animals, synthetic aurones ( 1 ) and ( 2 ) promoted reductions of 56.20 % and 57.61 % of the parasite load and stimulated the displacement towards the liver of the remaining adult worms. The oogram analysis revealed that the treatment with both aurones interferes with the egg development kinetics in the intestinal tissue. Seeking an action target for compounds ( 1 ) and ( 2 ), the connection with NTPDases enzymes, recognized as important therapeutic targets for S. mansoni, was evaluated. Molecular docking studies have shown promising results. The dataset reveals the anthelmintic character of these compounds, which can be used in the development of new therapies for schistosomiasis.     

cis-Jasmone indirect action on egg parasitoids (Hymenoptera: Scelionidae) and its application in biological control of soybean stink bugs (Hemiptera: Pentatomidae)

In many plants, the secondary metabolite cis-jasmone activates the metabolic pathway that produces volatile organic compounds attractive to natural enemies and, sometimes, repellent to herbivores. Previous studies indicate that the feeding damage caused by the herbivore Euschistus heros or the exogenous application of cis-jasmone in soybean plants induces the release of herbivore-induced plant volatiles (HIPVs) with a similar chemical profile and these compounds can attract the stink bug egg parasitoid Telenomus podisi (Scelionidae). Herein we tested in field conditions the effect of exogenous application of cis-jasmone in soybean plants on the parasitoid and stink bug community and on stink bug egg parasitism. In two areas, one within a soybean and another within a Crotalaria matrix, we randomly distributed 2 m² plots, with soybean plants induced (treatment, n = 5) or not induced by cis-jasmone (control, n = 5) in the field. We sampled the parasitoid community weekly with yellow sticky traps (n = 3/plot) and monitored parasitism with sentinel eggs of E. heros (n = 150/plot). We also monitored the population of stink bugs weekly, by sampling each plot with shake-cloth technique. The abundance of Scelionidae was highest overall and also in treated plots during the first four weeks in the area with a soybean matrix, but decreased thereafter. The richness of parasitoid families was similar between treatment and control plots in the area with a soybean matrix, but higher in control plots in the area with a Crotalaria matrix. Evenness was higher in control plots in the area with soybean matrix, whereas the reverse occurred in the area with a Crotalaria matrix. Results suggest that treatment with cis-jasmone effectively attracted and enhanced the population of scelionid parasitoids, but had no effect on the occurrence and intensity of parasitism and in the number of stink bugs.