In vitro anti-Leishmania activity and molecular docking of spiro-acridine compounds as potential multitarget agents against Leishmania infantum

Leishmaniasis is an infectious disease with several limitations regarding treatment schemes. This work reports the anti-Leishmania activity of spiroacridine compounds against the promastigote (IC₅₀ = 1.1 to 6.0 µg / mL) and amastigote forms of the best compounds (EC₅₀ = 4.9 and 0.9 µg / mL) inLeishmania (L.) infantumand proposes an in-silico study with possible selective therapeutic targets for L. infantum. The substituted dimethyl-amine compound (AMTAC 11) showed the best leishmanicidal activity in vitro, and was found to interact with TryRandLdTopoI. comparisons with standard inhibitors were performed, and its main interactions were elucidated. Based on the biological assessment and the structure-activity relationship study, the spiroacridine compounds appear to be promisinganti-leishmaniachemotherapeutic agents to be explored.

Genetic diversity and population structure of Brycon nattereri (Characiformes: Bryconidae): a Neotropical fish under threat of extinction

ABSTRACT Brycon nattereri is an endangered Neotropical fish reported along conserved stretches of the upper Paraná, Tocantins and São Francisco rivers. Populations of this species have been very rare in some Paraná River sub basins. This study analyzes the genetic diversity and population structure of B. nattereri in a restricted area of occurrence recently identified in upper Paraná River basin. Seven microsatellite loci and 497 bp of D-Loop mitochondrial region were examined in 92 individuals from four points along the area of occurrence. Both molecular markers indicated a single population distributed along a stretch of the river approximately 80 km long. Although some of the data suggest an ancient bottleneck, current levels of genetic diversity (H E = 0.574 and h = 0.616) were similar to those of other species of the genus Brycon. The results suggest that the population of B. nattereri has been able to maintain satisfactory levels of genetic diversity, in spite of the small area of occurrence. These data have highlighted an important conservation area and action may prove essential to improve the quality of the environment, and especially the water and riparian plant life, if the area is to be managed and conserved efficiently.

Isolation and characterization of 13 polymorphic microsatellite loci in Hypostomus ancistroides (Teleostei, Loricariidae) and cross-amplification in related species

This study details 13 novel polymorphic microsatellite loci in the armoured catfish Hypostomus ancistroides, and assesses their utility for population genetic studies. The analysis of 30 individuals revealed a total of 99 different alleles (ranging from two to 15 alleles per locus), with an average of 7·62 alleles per locus, with observed and expected heterozygosities ranging from 0·103 to 0·931 and from 0·102 to 0·906, respectively. One of the 13 loci showed significant deviations from Hardy-Weinberg equilibrium, probably due to the presence of null alleles, inferred from the excess of homozygotes.

DNA barcoding of freshwater ichthyoplankton in the Neotropics as a tool for ecological monitoring

Quantifying and classifying ichthyoplankton is one of the most effective ways of monitoring the recruitment process in fishes. However, correctly identifying the fish based on morphological characters is extremely difficult, especially in the early stages of development. We examined ichthyoplankton from tributaries and reservoirs along the middle stretch of the Paranapanema River, one of the areas most impacted by hydroelectric projects in the Neotropics. Matching DNA sequences of the COI gene (628-648 bp) allowed us to identify 99.25% of 536 samples of eggs (293) and larvae (243) subjected to BOLD-IDS similarity analysis with a species-level threshold of 1.3%. The results revealed 37 species in 27 genera, 15 families and four orders, some 23.8% of documented fish species in the Paranapanema River. Molecular identification meant that we could include data from egg samples that accounted for about 30% of the species richness observed. The results in this study confirm the efficacy of DNA barcoding in identifying Neotropical ichthyoplankton and show how the data produced provide valuable information for preparing plans for conserving and managing inland waters.

Development and characterization of 14 microsatellite loci in the Neotropical fish Geophagus brasiliensis (Perciformes, Cichlidae)

Fourteen polymorphic microsatellite loci were isolated and characterized for the Neotropical cichlid Geophagus brasiliensis and tested on 30 individuals belonging to a single population. Among the 14 loci described, four showed potential presence of null alleles, inferred from the excess of homozygous genotypes, and three of these loci showed significant deviations from Hardy-Weinberg equilibrium. Fifty-nine different alleles were detected (ranging from two to eight alleles per locus), with estimates of observed and expected heterozygosity ranging from 0·167 to 0·700 and from 0·269 to 0·825. Cross-amplification of primers was successful in five other cichlid species.

Occurrence of enterotoxigenic and nonenterotoxigenic Bacteroides fragilis in calves and evaluation of their antimicrobial susceptibility

Bacteroides fragilis is considered an important clinical pathogen and the most common anaerobe isolated from human and animal clinical specimens; enterotoxigenic strains produce diarrhea. The presence of enterotoxigenic (ETBF) and nonenterotoxigenic B. fragilis in stool samples from calves with or without acute diarrhea and the antimicrobial susceptibility of the strains were evaluated. The stool samples were plated onto a selective B. fragilis–bile–esculin agar, and incubated anaerobically (10% CO₂/90% N₂), at 37°C, for 72 h. Species of the B. fragilis group were identified by using the API 32‐A kit. Enterotoxigenic strains were detected by PCR and the cytotoxic assay. From 54 diarrhea and 54 nondiarrhea stools, 124 and 92 members of the B. fragilis group, respectively, were recovered. Only two ETBF strains were isolated from two different diarrhea samples and the bft gene was detected in both. Moreover, the bft gene was detected in DNA from four different diarrheal stools samples but no ETBF strain was recovered. All the bacteria were susceptible to chloramphenicol, imipenem, moxifloxacin, piperacillin/tazobactam, metronidazole and tigecycline. Most of the isolates from both calves with and without diarrhea were resistant to all metals. Our results are of concern, and suggest the need to increase the surveillance of antibiotic and metal resistance of this microbial group isolated from animal production such as calves.

Evaluation of the RAPD profiles from different body parts of Euglossa pleosticta Dressler male bees (Hymenoptera: Apidae, Euglossina)

In the current literature, information is scarce on which part of the adult insect body is suitable for isolation of genomic DNA for genetic analysis based on DNA-markers. In this study, we evaluated RAPD profiles generated from total genomic DNA isolated from distinct body parts (head, legs, thorax + wings and abdomen) of 12 males of Euglossa pleosticta Dressler. From the total of bands analyzed, 9.0% did not show reproducibility. Percent variations of bands in each body segment were: 1.1% (head); 0.4% (legs); 0.8% (thorax/wings) and 6.7% (abdomen). The much higher variation (chi2(one sample) = 10.27; df = 1; P < 0.01) in the RAPD profiles obtained by using DNA isolated from abdomen of the euglossine males suggests that this body part of adult insects should be avoided in DNA extraction procedures. Conversely, the low variation among the RAPD profiles obtained from amplifications of genomic DNA extracted from head, legs and thorax/wings indicates that all these body parts of male bees are equally useful and secure for using in isolation and amplification procedures of total genomic DNA.

Genetic similarity among male bees of Euglossa truncata Rebêlo & Moure (Hymenoptera: Apidae) revealed by RAPD markers

The genetic RAPD (random amplified polymorphic DNA) markers have been used successfully in taxonomical studies of several groups of organisms. In the present study these molecular markers were used to analyze the genetic similarity among eighteen males of Euglossa truncata Rebêlo & Moure exhibiting variations in two morphological characters (colour of the antennal scape and metaepisternal hairs) which are frequently used to identify this species of euglossine bee. The twelve primers used in the RAPD analysis amplified 127 loci, of which 40 (31.5%) were polymorphic, showing some variation among the individuals. The coefficients of genetic similarity among the individuals ranged from 0.79 to 0.95, indicating a rather high genetic similarity among the 18 male bees studied. No RAPD band was specific to any morphological character analyzed. The results indicate that all bees analyzed belong to the same species. The high genetic similarity among the eighteen euglossine males studied indicates that the variations observed in the morphological characters are not in disagreement with the identification of this species of Euglossina and these characters can vary among males of E. truncata.