Formicidal activity of indole derivatives on Atta opaciceps (Borgmeier): Lethal,behavioural and locomotive effects

The leaf‐cutting ants of the genus Atta are of extreme importance for agriculture and forestry. Few active products can be employed to control these pests and, therefore, the discovery of new insecticidal products represents a fundamental strategy for its management. In this study, we evaluated the mortality, behaviour and locomotion of workers of Atta opaciceps (Borgmeier) exposed to synthesized indole derivatives. The most active compound was 4d [1‐(1H‐indol‐3‐yl)pentan‐1‐one] (LD₅₀ = 0.018 μg/mg), while the 4e [1‐(1H‐indol‐3‐yl)hexan‐1‐one] (LD₅₀ = 3.82 μg/mg) was the least active compound. These two derivatives reduced the survival of A. opaciceps over time and altered the behaviour and locomotion of these ants. This study demonstrates the potential of indole derivatives to produce new formicidal products, since, in addition to being effective, it also affects the ant's behaviour and locomotion.     

Biological maturation influences selection process in youth elite soccer players

This study examined the influence of birth date, salivary testosterone [sT] concentration, sexual maturity status, and general strength on the selection process of an elite Brazilian soccer club during a 12-month period, which was a 2^nd phase of a 24-month selection process. The stature, body mass, sT, sexual maturity status [Tanner scale], and hand grip strength were assessed for 143 players during 2 weeks. From these 143 players, 100 players were dismissed [DIS] and 43 players were selected to integrate the club’s under-14 squad. Following 1-year training period, the under-14 team was assembled with 9 players designated as starters [STA], and then, comparisons were conducted taking into account a group of non-starters (selected; SEL = 34 players) and STA (n = 09). The DIS, SEL, STA players, and reference population, were compared for birth distribution. A greater proportion of players was born in the first trimester in the STA [75.0%], SEL [57.1%] and DIS [50.0%] groups compared to the reference population [25.8%]. One-way ANOVA showed a higher sT for STA group [516.0 ± 129.9 pmol·L^-1], compared to SEL [415.5 ± 117.9 pmol·L^-1] and DIS groups [390.9 ± 84.9 pmol·L^-1; p = 0.003), and Kruskall-Wallis test showed a higher gonadal development for STA compared to DIS [p = 0.001]. The current findings suggest a strong influence of birth date and biological maturation on young soccer players selection process. Soccer coaches should consider these influences when making decisions about player selection of elite youth players.     

Parasite load evaluation by qPCR and blood culture in Chagas disease and HIV co-infected patients under antiretroviral therapy

Chagas disease also known as American trypanosomiasis, is caused by Trypanosoma cruzi and transmitted by triatominae-contaminated feces. It is considered a neglected tropical disease that affects 6 to 7 million people worldwide. The reactivation of Chagas disease occurs when the chronically infected hosts are not able to control T. cruzi infection, generating recurrence of the acute phase. HIV is the main immunosuppressive infection that can lead to the reactivation of chronic Chagas disease in AIDS conditions. In co-infected patients, the reactivation of Chagas disease is related to their high parasite load, high HIV viral load, and CD4 T-cell counting less than 200/mm³, which may evolve to meningoencephalitis and myocarditis. Eight T. cruzi/HIV co-infected patients under antiretroviral therapy (ART) and ten Chagas disease patients without HIV infection that attended at Study Group of Chagas Disease, Hospital de Clínicas, University of Campinas (GEdoCh/HC/UNICAMP-SP) and Pontifical Catholic University of Campinas SP (PUCC/SP) were evaluated. Tests for Chagas disease were performed, such as qPCR and T. cruzi blood culture. The patient’s medical records were analyzed to verify clinical and epidemiological data, viral load, and CD4 T-cell counting since the outset of ART. For both groups, we found no statically significant differences between parasite load via blood culture and qPCR. In T. cruzi/HIV co-infected subjects, we observed a significant increase of CD4 T-cells counting and viral load decrease, which became undetectable over the years after ART. Parasites isolated from the patient’s blood culture were genotyped, being the majority of them infected with TcII and one case of mixed infection (TcII and TcV/TcVI). These results were expected according to the region of origin of the patients. We suggest that the parasite load be monitored through qPCR in T.cruzi/HIV co-infected patients. We conclude that ART in people living with HIV improves infection and immunosuppression control, enabling the natural evolution of the American trypanosomiasis.     

Thrombospondin-1 expression and modulation of Wnt and hippo signaling pathways during the early phase of Trypanosoma cruzi infection of heart endothelial cells

The protozoan parasite, Trypanosoma cruzi, causes severe morbidity and mortality in afflicted individuals. Approximately 30% of T. cruzi infected individuals present with cardiac pathology. The invasive forms of the parasite are carried in the vascular system to infect other cells of the body. During transportation, the molecular mechanisms by which the parasite signals and interact with host endothelial cells (EC) especially heart endothelium is currently unknown. The parasite increases host thrombospondin-1 (TSP1) expression and activates the Wnt/β-catenin and hippo signaling pathways during the early phase of infection. The links between TSP1 and activation of the signaling pathways and their impact on parasite infectivity during the early phase of infection remain unknown. To elucidate the significance of TSP1 function in YAP/β-catenin colocalization and how they impact parasite infectivity during the early phase of infection, we challenged mouse heart endothelial cells (MHEC) from wild type (WT) and TSP1 knockout mice with T. cruzi and evaluated Wnt signaling, YAP/β-catenin crosstalk, and how they affect parasite infection. We found that in the absence of TSP1, the parasite induced the expression of Wnt-5a to a maximum at 2 h (1.73±0.13), P< 0.001 and enhanced the level of phosphorylated glycogen synthase kinase 3β at the same time point (2.99±0.24), P<0.001. In WT MHEC, the levels of Wnt-5a were toned down and the level of p-GSK-3β was lowest at 2 h (0.47±0.06), P< 0.01 compared to uninfected control. This was accompanied by a continuous significant increase in the nuclear colocalization of β-catenin/YAP in TSP1 KO MHEC with a maximum Pearson correlation coefficient of (0.67±0.02), P< 0.05 at 6 h. In WT MHEC, the nuclear colocalization of β-catenin/YAP remained steady and showed a reduction at 6 h (0.29±0.007), P< 0.05. These results indicate that TSP1 plays an important role in regulating β-catenin/YAP colocalization during the early phase of T. cruzi infection. Importantly, dysregulation of this crosstalk by pre-incubation of WT MHEC with a β-catenin inhibitor, endo-IWR 1, dramatically reduced the level of infection of WT MHEC. Parasite infectivity of inhibitor treated WT MHEC was similar to the level of infection of TSP1 KO MHEC. These results indicate that the β-catenin pathway induced by the parasite and regulated by TSP1 during the early phase of T. cruzi infection is an important potential therapeutic target, which can be explored for the prophylactic prevention of T. cruzi infection.     

Haplotypes of single cancer driver genes and their local ancestry in a highly admixed long-lived population of Northeast Brazil

Admixed populations have not been examined in detail in cancer genetic studies. Here, we inferred the local ancestry of cancer-associated single nucleotide polymorphisms (SNPs) and haplotypes of a highly admixed Brazilian population. SNP array was used to genotype 73 unrelated individuals aged 80-102 years. Local ancestry inference was performed by merging genotyped regions with phase three data from the 1000 Genomes Project Consortium using RFmix. The average ancestry tract length was 9.12-81.71 megabases. Strong linkage disequilibrium was detected in 48 haplotypes containing 35 SNPs in 10 cancer driver genes. All together, 19 risk and eight protective alleles were identified in 23 out of 48 haplotypes. Homozygous individuals were mainly of European ancestry, whereas heterozygotes had at least one Native American and one African ancestry tract. Native-American ancestry for homozygous individuals with risk alleles for HNF1B, CDH1, and BRCA1 was inferred for the first time. Results indicated that analysis of SNP polymorphism in the present admixed population has a high potential to identify new ancestry-associated alleles and haplotypes that modify cancer susceptibility differentially in distinct human populations. Future case-control studies with populations with a complex history of admixture could help elucidate ancestry-associated biological differences in cancer incidence and therapeutic outcomes.     

On the mechanisms of internalization and intracellular delivery mediated by pH-sensitive liposomes

We investigated the molecular mechanisms by which pH-sensitive liposomes surpass the cytoplasmic and endosomal membranes to deliver their aqueous contents into the cytoplasm. Various liposome formulations were evaluated for their efficacy to mediate intracellular delivery of encapsulated material, including a novel sterically stabilized pH-sensitive formulation ((DOPE:CHEMS:DSPE-PEG(2000) (6:4:0.3)) that was previously developed in our laboratories. In an attempt to fully characterize the nature of liposome-cell interactions different approaches based on a dual-labeling fluorescence assay were used. Our results indicate that the efficacy of interaction of pH-sensitive liposomes, both plain and sterically stabilized, with cells is strongly determined by the inclusion of DOPE in their composition, independently of the type of the amphiphilic stabilizer used. In fact, DOPE-containing liposomes shown to be non-pH sensitive by biophysical assays, mediated cytoplasmic delivery of their contents as efficiently as well known pH-sensitive formulations (e.g. DOPE:CHEMS). However, among the different formulations studied, DOPE:CHEMS liposomes were those exhibiting the highest extent of cell association. Moreover, our results with cells pretreated with metabolic inhibitors or lysosomotropic agents clearly indicate that DOPE-containing liposomes are internalized essentially by endocytosis and that acidification of the endosomes is not the only mechanism involved in the destabilization of the liposomes inside the cell.     

Anopheles albitarsis eggs: ultrastructural analysis of chorion layers after permeabilization

Construction of transgenic Anopheles mosquitoes refractory to Plasmodium requires knowledge of mosquito developmental biology. In order to study Anopheles embryology the removal or, alternatively, the permeabilization of the melanized and sclerotized egg chorion were attempted. The protocol classically used for chorion removal of Drosophila eggs was applied, with partial efficacy, to Anopheles albitarsis, a neotropical malaria vector. Each step was monitored by scanning electron microscopy and the results suggest differences in chorion composition between the two taxa. As an alternative to chorion removal, mosquito eggs were permeabilized with benserazide, an inhibitor of Dopa Decarboxylase, one of the enzymes needed for mosquito eggshell sclerotization. Embryo morphology and viability were not affected by this treatment. Permeabilization of the egg chorion allowed the ultrastructural observation of an internal homogeneous endochorion and an external compound exochorion, the latter consisting of a basal lamellar layer and protruding tubercles.     

Electrochemical sensing of the behaviour of oligonucleotide lipoplexes at charged interfaces

Complexes between short oligodeoxynucleotides (ODN) with a variable dG(x)dC(y) base composition and liposomes composed of the cationic lipid DOTAP (ODN lipoplexes) were studied by differential pulse voltammetry at a glassy carbon electrode. Since lipoplexes are spontaneously formed by electrostatic interactions, the objective of the voltammetric study was to investigate their behaviour at the electrode surface/solution interface. It was verified that the peak current in the voltammograms for ODN lipoplexes was due to guanosine oxidation and that it was influenced both by the applied adsorption potential and the lipoplex (+/-) charge ratio used. It was found that for low ODN lipoplexes (+/-) charge ratios the peak current obtained was enhanced when compared to that registered with free ODN for the same concentration. This allowed a higher sensitivity in the determination of ODN by differential pulse voltammetry and a limit of detection of 5.5 ng/mL was achieved. A model that explains the organisation of ODN lipoplexes at the electrode surface/solution interface is proposed. The electrochemical results presented account for a better physicochemical characterisation of lipoplexes at charged interfaces, which can be important for the understanding and development of gene therapy vectors based on ODN lipoplexes.     

Content and Concentration of Taurine,Hypotaurine, and Zinc in the Retina,the Hippocampus,and the Dentate Gyrus of the Rat at Various Postnatal Days

Taurine and zinc possess neurotrophic and neuroprotective properties, and they have been demonstrated to interact in the central nervous system (CNS). The aim of this work was to determine taurine, hypotaurine, and zinc levels during postnatal development and any possible significant correlation between them in selective areas of the CNS with differential taurine level regulation and intrinsic capacity to proliferate. Taurine and hypotaurine content (nM/region) and concentration (nM/mg protein) and total zinc levels were determined in the retina, hippocampus, and dentate gyrus of the rat at postnatal days 5, 10, 15, 20, 30, and 50. Taurine and hypotaurine increased during development in the retina without significant correlation between them. In the hippocampus there was a progressive decrease, and in the dentate gyrus there was an initial increase and a posterior decrease of taurine and hypotaurine levels. Correlation between the two amino acids was observed at P10, P15, and P50 for the hippocampus and at P15, P30, and P50 for the dentate gyrus. The variations in total zinc levels followed a biphasic behavior, with an early decrease and later increase. Significant and positive correlation of zinc and taurine was only observed in the hippocampus at P30 and P50 and negative in the dentate gyrus at P30. No significant correlation was obtained for the retina. The maintenance of taurine levels in specific CNS areas does not seem to be related to the availability of the precursor, hypotaurine, which might have a role by itself. There are critical postnatal periods during which there is a preservation of taurine, hypotaurine, or zinc levels. It seems that these requirements could be related to zinc-taurine interactions.