RESUMO Atualmente é crescente o interesse pela investigação de compostos bioativos de fontes naturais. Nesse contexto, o presente estudo investigou o conteúdo fenólico, capacidade antioxidante e atividade antimicrobiana do extrato hidroalcoólico (EHA) das cascas do caule e folhas de Stryphnodendron adstringens (Mart.) Coville. Partes da planta foram extraídas com etanol: água (1:1) e filtradas a vácuo para obtenção do extrato bruto. O conteúdo fenólico foi determinado pelo método de Folin-Ciocalteu. A atividade antioxidante foi medida pelo teste DPPH. A atividade antimicrobiana dos extratos foi avaliada contra cocos Gram-positivos: Staphylococcus aureus (ATCC 25923) e Staphylococcus epidermidis (cepa isolada de paciente); bacilos Gram-negativos: Escherichia coli (ATCC 25922) e Pseudomonas aeruginosa (ATCC 27853). A zona de inibição e concentração inibitória mínima (CIM) dos extratos vegetais foram avaliadas pelo método de disco difusão em ágar e microdiluição em caldo, respectivamente. O conteúdo fenólico total dos EHAs foi maior nas cascas do caule (970,4 mg GAE/g) do que nas folhas (693,8 mg GAE/g). No ensaio DPPH, todos os extratos apresentaram alta atividade antioxidante, acima de 75% na concentração de 100 μg/mL. Sobre a atividade antimicrobiana, todos os EHAs apresentaram efeitos contra bactérias Gram-positivas S. aureus e S. epidermidis, cuja CIM variou de 7,81 μg/mL a 62,5 μg/mL. Essa descoberta é importante, uma vez que esses patógenos geralmente são resistentes a uma variedade de antibióticos amplamente conhecidos. Portanto, esses resultados são promissores e indicam o uso de S. adstringens (Mart.) Coville (Barbatimão) como antioxidante natural em alimentos, medicamentos e também apontam para seu uso na terapia antimicrobiana.

ABSTRACT There is currently growing interest in the investigation of bioactive compounds from natural sources. In this context, this study investigated the phenolic content, antioxidant capacity, and antimicrobial activity of the hydroalcoholic extract (EHA) of the stem barks and leaves of Stryphnodendron adstringens. Plant parts were extracted with ethanol:water (1:1) and filtered in a vacuum to obtain the crude extract. Phenolic content was determined by the Folin-Ciocalteu method. Antioxidant activity was measured using the DPPH test. The antimicrobial activity of extracts was evaluated against Gram-positive cocci: Staphylococcus aureus (ATCC 25923) and Staphylococcus epidermidis (strain isolated from a patient); and Gram-negative bacilli: Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853). The zone of inhibition and the minimum inhibitory concentration (MIC) of the plant extracts were evaluated by the agar diffusion disc method and broth microdilution, respectively. Total phenolic content of the EHAs was higher in stem barks (970.4 mg GAE/g) than in leaves (693.8 mg GAE/g). In the DPPH assay, all extracts showed high antioxidant activity, above 75% at the concentration of 100 μg/mL. About antimicrobial activity, all the EHAs showed effects against Gram-positive bacteria S. aureus andS. epidermidis, whose MIC ranged from 7.81 μg/mL to 62.5 μg/mL. This finding is important since these pathogens are generally resistant to a variety of widely known antibiotics. Therefore, these results are promising and indicate the use of S. adstringens (Mart.) Coville as a natural antioxidant in foods, medicines and also point to its use in antimicrobial therapy.

BACKGROUND Key genes control the infectivity of the Schistosoma haematobium causing schistosomiasis. A method for understanding the regulation of these genes might help in developing new disease strategies to control schistosomiasis, such as the silencing mediated by microRNAs (miRNAs). The miRNAs have been studied in schistosome species and they play important roles in the post-transcriptional regulation of genes, and in parasite-host interactions. However, genome-wide identification and characterisation of novel miRNAs and their pathway genes and their gene expression have not been explored deeply in the genome and transcriptome of S. haematobium. OBJECTIVES Identify and characterise mature and precursor miRNAs and their pathway genes in the S. haematobium genome. METHODS Computational prediction and characterisation of miRNAs and genes involved in miRNA pathway from S. haematobium genome on SchistoDB. Conserved domain analysis was performed using PFAM and CDD databases. A robust algorithm was applied to identify mature miRNAs and their precursors. The characterisation of the precursor miRNAs was performed using RNAfold, RNAalifold and Perl scripts. FINDINGS We identified and characterised 14 putative proteins involved in miRNA pathway including ARGONAUTE and DICER in S. haematobium. Besides that, 149 mature miRNAs and 131 precursor miRNAs were identified in the genome including novel miRNAs. MAIN CONCLUSIONS miRNA pathway occurs in the S. haematobium, including endogenous miRNAs and miRNA pathway components, suggesting a role of this type of non-coding RNAs in gene regulation in the parasite. The results found in this work will open up a new avenue for studying miRNAs in the S. haematobium biology in helping to understand the mechanism of gene silencing in the human parasite Schistosome.

BACKGROUND Biomphalaria glabrata is the major species used for the study of schistosomiasis-related parasite-host relationships, and understanding its gene regulation may aid in this endeavor. The ubiquitin-proteasome system (UPS) performs post-translational regulation in order to maintain cellular protein homeostasis and is related to several mechanisms, including immune responses. OBJECTIVE The aims of this work were to identify and characterise the putative genes and proteins involved in UPS using bioinformatic tools and also their expression on different tissues of B. glabrata. METHODS The putative genes and proteins of UPS in B. glabrata were predicted using BLASTp and as queries reference proteins from model organism. We characterised these putative proteins using PFAM and CDD software describing the conserved domains and active sites. The phylogenetic analysis was performed using ClustalX2 and MEGA5.2. Expression evaluation was performed from 12 snail tissues using RPKM. FINDINGS 119 sequences involved in the UPS in B. glabrata were identified, which 86 have been related to the ubiquitination pathway and 33 to proteasome. In addition, the conserved domains found were associated with the ubiquitin family, UQ_con, HECT, U-box and proteasome. The main active sites were lysine and cysteine residues. Lysines are responsible and the starting point for the formation of polyubiquitin chains, while the cysteine residues of the enzymes are responsible for binding to ubiquitin. The phylogenetic analysis showed an organised distribution between the organisms and the clades of the sequences, corresponding to the tree of life of the animals, for all groups of sequences analysed. The ubiquitin sequence was the only one with a high expression profile found in all libraries, inferring its wide range of performance. MAIN CONCLUSIONS Our results show the presence, conservation and expression profile of the UPS in this mollusk, providing a basis and new knowledge for other studies involving this system. Due to the importance of the UPS and B. glabrata, this work may influence the search for new methodologies for the control of schistosomiasis.