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.     

Lichenochemical Screening and Antioxidant Capacity of Four Tunisian Lichen Species

The phenolic composition and antioxidant capacity of four Tunisian lichen species, Cladonia rangiformis, Flavoparmelia caperata, Squamarina cartilaginea and Xanthoria parietina, were determined in order to provide a better understanding of their lichenochemical composition. Powdered material of F. caperata was the richest in total phenolic content (956.68 μg GAE g⁻¹ DW) and S. cartilaginea in proanthocyanidin content (77.31 μg CE g⁻¹ DW), while the acetone extract of X. parietina showed the highest flavonoid content (9.56 μg CE g⁻¹ DW). The antioxidant capacity of all lichen extracts and crude material was evaluated by DPPH^. scavenging, iron-chelating, and iron-reducing powers. Results showed that methanol extracts of S. cartilaginea had the highest DPPH^. antioxidant capacity (IC₅₀=0.9 μg mL⁻¹) and the highest iron-reducing power was attributed to the acetone extract of this species. All extracts of all species were further screened by Fourier-transform infrared spectroscopy (FT-IR) and nuclear resonance spectroscopy (NMR); results showed an abundance of phenols, aromatic compounds, and fatty acids. Overall, our results showed that the investigated species are a rich source of potentially bioactive compounds with valuable properties.     

Toxicity of rhizomes of the invasive Hedychium coronarium (Zingiberaceae) on aquatic species

The production and release of chemical compounds by invasive plants can affect competitors and native species overall, destabilizing ecological interactions and harming ecosystem functioning. Hedychium coronarium is an invasive macrophyte common on Brazilian riparian areas that produces a wide variety of allelochemicals, but little is known about their effect on aquatic species. Here, we identified the major chemical compounds of the aqueous extract of H. coronarium rhizomes and assessed its toxicity, evaluating the growth inhibition of one alga (Raphidocelis subcapitata) and one macrophyte (Lemna minor), and the lethality of cladoceran (Ceriodaphnia silvestrii and Daphnia similis) and Chironomidae larvae (Chironomus sancticaroli). The majoritarian compounds of H. coronarium rhizomes were Coronarin D and Coronarin D Ethyl Ether. The aqueous extract was toxic for all tested species. We observed growth inhibition in R. subcapitata, as well as reduction in biomass in L. minor. Chironomus sancticaroli and cladoceran were the most sensible species. The aqueous extract of H. coronarium rhizomes was toxic on tested conditions, suggesting that the rhizome compounds may interfere on aquatic organisms and in the dynamic of trophic webs of aquatic ecosystems on invaded areas.

     

Relationship between ventilatory threshold and muscle fiber conduction velocity responses in trained cyclists

The relationship between surface electromyography (SEMG) amplitude and the ventilatory threshold has been extensively studied. However, previous studies of muscle fiber conduction velocity (MFCV) are scarce and present insufficient evidence concerning the relationship between MFCV and metabolic responses during cycling. Based on that fact, the purpose of this study is twofold: (1) to investigate the existence of a MFCV threshold (MFCVT) during cycling and (2) to verify if this possible breakpoint is correlated with the ventilatory threshold (VT) and the SEMG threshold (SEMGT). Eight trained male cyclists (age 36.0 ± 9.7 years) performed an incremental cycling test with initial workload of 150 W gradually incremented by 20 W min^?1 until the exhaustion. Gas analyses were conducted using a breath-by-breath open-circuit spirometry and SEMG were registered from vastus lateralis in each pedaling cycle with a linear array of electrodes. A bi-segmental linear regression computer algorithm was used to estimate VT, MFCVT and SEMGT respectively in the carbon dioxide production (VCO₂), MFCV and electromyography root mean square (EMG RMS) curves. The one way ANOVA for repeated measures did not reveal any significant difference among VT (77.1 ± 7.5% of VO₂max), MFCVT (80.3 ± 10.4% of VO₂max) and SEMGT (81.9 ± 11.7% of VO₂max). The Bland and Altman procedure confirmed a good concordance between SEMGT and VT (Bias = 5.5 of %VO₂max) as well as MFCVT and VT (Bias = 5.2 of %VO₂max). The present findings suggest that muscle fiber conduction velocity threshold is a valid and reliable non-invasive tool to obtain information about ventilatory threshold in trained cyclists.     

Carvedilol inhibition of lipid peroxidation. A new antioxidative mechanism

To define the molecular mechanism(s) of carvedilol inhibition of lipid peroxidation we have utilized model systems that allow us to study the different reactions involved in this complex process.

Carvedilol inhibits the peroxidation of sonicated phosphatidylcholine liposomes triggered by FeCl₂ addition whereas atenolol, pindolol and labetalol are ineffective. The inhibition proved not to be ascribable (a) to an effect on Fe²⁺ autoxidation and thus on the generation of oxygen derived radical initiators; (b) to the scavenging of the inorganic initiators O^·-₂ and ^·OH; (c) to an effect on the reductive cleavage of organic hydroperoxides by FeCl₂; (d) to the scavenging of organic initiators. The observations that (a) carvedilol effectiveness is inversely proportional to the concentration of FeCl₂ and lipid hydroperoxides in the assay; (b) the drug prevents the onset of lipid peroxidation stimulated by FeCl₃ addition and; (c) it can form a complex with Fe³⁺, suggest a molecular mechanism for carvedilol action. It may inhibit lipid peroxidation by binding the Fe³⁺ generated during the oxidation of Fe²⁺ by lipid hydroperoxides in the substrate. The lag time that carvedilol introduces in the peroxidative process would correspond to the time taken for carvedilol to be titrated by Fe³⁺; when the drug is consumed the Fe³⁺ accumulates to reach the critical parameter that stimulates peroxidation. According to this molecular mechanism the antioxidant potency of carvedilol can be ascribed to its ability to bind a species, Fe³⁺, that is a catalyst of the process and to its lipophilic nature that concentrates it in the membranes where Fe³⁺ is generated by a site specific mechanism.     

Climatic factors and population density of Lutzomyia longipalpis (Lutz & Neiva, 1912) in an urban endemic area of visceral leishmaniasis in midwest Brazil

The life cycle of vectors and the reservoirs that participate in the chain of infectious diseases have a strong relationship with the environmental dynamics of the ecosystems in which they live. Oscillations in population abundance and seasonality of insects can be explained by factors inherent in each region and time period. Therefore, knowledge of the relationship and influence of environmental factors on the population of Lutzomyia longipalpis is necessary because of the high incidence of visceral leishmaniasis (VL) in Brazil. This study evaluates the influence of abiotic variables on the population density and seasonal behavior of L. longipalpis in an urban endemic area of VL in Brazil. The sand fly captures were performed every two months between November, 2009 and November, 2010 in the peridomicile of 13 randomly selected residences. We captured 1,367 specimens of L. longipalpis, and the ratio of male/female flies was 2.86:1. The comparison of the total male specimens in the two seasons showed a statistical difference in the wet season, but there was no significant difference when considering the total females. With respect to climatic variables, a significant negative association was observed only with wind speed. During periods of high wind speeds, the population density of this vector decreased. The presence of L. longipalpis was found in all months of the study with bimodal behavior and population peaks during the wet season.     

Beginning to understand the role of sugar carriers in Colletotrichum lindemuthianum: the function of the gene mfs1

Fungi of the Colletotrichum genus are among the most prominent phytopathogens that cause diseases with a considerable economic impact, such as anthracnose. The hemibiotrophic fungus Colletotrichum lindemuthianum (teleomorph Glomerella cingulata f. sp. phaseoli) is the causal agent of the anthracnose of the common bean; and similarly to other phytopathogens, it uses multiple strategies to gain access to different carbon sources from its host. In this study, we examine mfs1, a newly identified C. lindemuthianum hexose transporter. The mfs1 gene is expressed only during the necrotrophic phase of the fungus’ interaction within the plant and allows it to utilize the available sugars during this phase. The deletion of mfs1 gene resulted in differential growth of the fungus in a medium that contained glucose, mannose or fructose as the only carbon source. This study is the first to describe a hexose transporter in the hemibiotrophic pathogen C. lindemuthianum and to demonstrate the central role of this protein in capturing carbon sources during the necrotrophic development of the plant/pathogen interaction.     

Ultrastructure and morphogenesis of the wing scales in Heliconius erato phyllis (Lepidoptera: Nymphalidae): What silvery/brownish surfaces can tell us about the development of color patterning?

Usually the literature on Heliconius show three types of scales, classified based on the correlation between color and ultrastructure: type I – white and yellow, type II – black, and type III – orange and red. The ultrastructure of the scales located at the silvery/brownish surfaces of males/females is for the first time described in this paper. Besides, we describe the ontogeny of pigmentation, the scale morphogenesis and the maturation timing of scales fated to different colors in Heliconius erato phyllis. The silvery/brownish surfaces showed ultrastructurally similar scales to the type I, II and III. The ontogeny of pigmentation follows the sequence red, black, silvery/brownish and yellow. The maturation of yellow-fated scales, however, occurred simultaneously with the red-fated scales, before the pigmentation becomes visible. In spite of the scales at the silvery/brownish surfaces being ultrastructurally similar to the yellow, red and black scales, they mature after them; this suggests that the maturation timing does not show a relationship with the scale ultrastructure, with the deposition timing of the yellow pigment. The analysis of H. erato phyllis scale morphogenesis, as well as the scales ultrastructure and maturation timing, provided new findings into the developmental architecture of color pattern in Heliconius.     

Sexual Size Dimorphism in the Color Pattern Elements of Two Mimetic Heliconius Butterflies

Sexual dichromatism and sexual dimorphism of body size are reasonably well studied in butterflies. Sexual size dimorphism of color pattern elements, however, is much less explored. The object of this study is Heliconius, a genus of butterflies well known for the coevolution between mate color preferences and mimicry. Given the sexual role of wing coloration, we investigated the existence of sexual size dimorphism in the wing color elements of a mimetic pair—Heliconius erato phyllis Fabricius and Heliconius besckei Ménétriés—and analyzed the allometric patterns of these traits. Correlation between size of elements in the dorsal and ventral wing surfaces were also estimated. In both species, three out of four elements were larger in males, but the non-dimorphic element was not the same. With regard to the allometric patterns, our most important finding was that smaller males of one species have proportionally larger yellow bars. This is the first study specifically concerning quantitative sexual dimorphism in the coloration of this well-known genus of butterflies and it opens new prospects to investigate sex-related natural selection and sexual selection of color pattern elements.