Expression and cellular localisation of Trypanosoma cruzi calpains

BACKGROUND Calpains are present in almost all organisms and comprise a family of calcium-dependent cysteine peptidases implicated in crucial cellular functions. Trypanosoma cruzi, the causative agent of Chagas disease, presents an expansion on this gene family with unexplored biological properties. OBJECTIVES Here, we searched for calpains in the T. cruzi genome, evaluated the mRNA levels, calpain activity and the protein expression and determined the cellular localisation in all three parasite life cycle forms. METHODS/FINDINGS Sixty-three calpain sequences were identified in T. cruzi CL Brener genome, with fourteen domain arrangements. The comparison of calpain mRNA abundance by quantitative polymerase chain reaction (qPCR) revealed seven up-regulated sequences in amastigotes and/or bloodstream trypomastigotes and five in epimastigotes. Western Blotting analysis revealed seven different molecules in the three parasite forms, and one amastigote-specific, while no proteolytic activity could be detected. Flow cytometry assays revealed a higher amount of intracellular calpains in amastigotes and/or trypomastigotes in comparison to epimastigotes. Finally, ultrastructural analysis revealed the presence of calpains in the cytoplasm, vesicular and plasma membranes of the three parasite forms, and in the paraflagellar rod in trypomastigotes. CONCLUSION Calpains are differentially expressed and localised in the T. cruzi life cycle forms. This study adds data on the calpain occurrence and expression pattern in T. cruzi.

Activity of Piperaceae extracts and fractions in the control of Phytomonas serpens / Atividade de extratos e frações de Piperaceae no controle de Phytomonas serpens

ABSTRACT: Protozoa of the genus Phytomonas are harmful parasites to several agricultural crops of economic importance. Due to their recognized biological activity, crude extracts of Piper aduncum, P. crassinervium, P. hispidum, and P. amalago leaves, were tested using the microdilution plate technique to assess the antiparasitic potential against Phytomonas serpens. Results showed that the ethanolic crude extract of P. crassinervium and P. amalago presented the best inhibitory concentration for 50% of the cells (IC50), 16.5 µg mL-1 in chloroform phase, and 18 µg mL-1 in aqueous phase, respectively, after 48 h treatment. Cytotoxicity analyses were performed using the colorimetric method of sulforhodamine-B in LLCMK2 mammalian cells. The chloroform phase of P. crassinervium was subjected to the fractionation process, in which the ethyl acetate and dichloromethane fractions obtained better IC50 values. Scanning electron microscopy (SEM) images showed alterations in the cell membrane of the treated parasites. The data obtained indicate a potential antiparasitic effect of the Piper species analyzed against P. serpens, being considered promising candidates for formulations of bioproducts to control the parasite.

RESUMO: Protozoários do gênero Phytomonas são parasitas prejudiciais a várias culturas agrícolas de importância econômica. Devido a sua atividade biológica reconhecida, extratos brutos de folhas de Piper aduncum, P. crassinervium, P. hispidum e P. amalago, foram testadas pela técnica de microdiluição em placa para avaliar o seu potencial antiparasitário contra Phytomonas serpens. Os resultados mostraram que o extrato bruto etanólico de P. crassinervium e P. amalago apresentaram as melhores concentrações inibitórias para 50% das células (IC50), 16,5 µg mL-1 na fase clorofórmio e 18 µg mL-1 na fase aquosa, respectivamente, após 48 h de tratamento. Análises de citotoxicidade foram realizadas através do método colorimétrico da sulforodamina-B, em células de mamíferos LLCMK2. A fase clorofórmio de P. crassinervium foi submetida ao processo de fracionamento, no qual as frações acetato de etila e diclorometano obtiveram melhores valores de IC50. Imagens de microscopia eletrônica de varredura (MEV) mostraram alterações na membrana celular dos parasitas tratados com fase aquosa de P. amalago. Os dados obtidos indicam potencial efeito antiparasitário das espécies de Piper analisadas contra P. serpens, sendo consideradas candidatas promissoras para formulações de bioprodutos para controle do parasito.

Calpains of Leishmania braziliensis: genome analysis, differential expression, and functional analysis

BACKGROUND Calpains are proteins belonging to the multi-gene family of calcium-dependent cysteine peptidases that undergo tight on/off regulation, and uncontrolled proteolysis of calpains is associated with severe human pathologies. Calpain orthologues are expanded and diversified in the trypanosomatids genome. OBJECTIVES Here, we characterised calpains in Leishmania braziliensis, the main causative agent of cutaneous leishmaniasis in Brazil. METHODS/FINDINGS In total, 34 predicted calpain-like genes were identified. After domain structure evaluation, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) during in vitro metacyclogenesis revealed (i) five genes with enhanced expression in the procyclic stage, (ii) one augmented gene in the metacyclic stage, and (iii) one procyclic-exclusive transcript. Western blot analysis revealed that an antibody against a consensus-conserved peptide reacted with multiple calpain-like proteins, which is consistent with the multi-gene family characteristic. Flow cytometry and immunocytochemistry analyses revealed the presence of calpain-like molecules mainly in the cytoplasm, to a lesser extent in the plasma membrane, and negligible levels in the nucleus, which are all consistent with calpain localisation. Eventually, the calpain inhibitor MDL28170 was used for functional studies revealing (i) a leishmaniostatic effect, (ii) a reduction in the association index in mouse macrophages, (iii) ultra-structural alterations conceivable with autophagy, and (iv) an enhanced expression of the virulence factor GP63. CONCLUSION This report adds novel insights into the domain structure, expression, and localisation of L. braziliensis calpain-like molecules.

Serodiagnosis of visceral and cutaneous leishmaniasis in human and canine populations living in Indigenous Reserves in the Brazilian Amazon Region

ABSTRACT INTRODUCTION: Leishmaniasis is endemic to the Northern, Northeastern, Central-Western, and Southeastern regions of Brazil. We aimed to assess the epidemiological situation of leishmaniasis in humans and dogs in indigenous villages located in the States of Mato Grosso and Tocantins using a serological survey conducted in May 2011. METHODS: Serum samples were collected from 470 humans and 327 dogs living in villages of the Urubu Branco and Tapirapé Karajá indigenous reserves. The samples were analyzed for the presence of Leishmania spp. antibodies using the indirect fluorescent antibody test (IFAT), enzyme-linked immunosorbent assay (ELISA) with a crude antigen (CA) and soluble antigen (SA), and Dual Path Platform (DPP®) immunoassay for canine visceral leishmaniasis. RESULTS: Of 470 human samples tested, two (0.4%) were positive using IFAT. Among 327 dog samples tested, 28 (8.6%) were positive using ELISA CA, five (1.5%) using ELISA SA, two (0.6%) using IFAT, and none using DPP® immunoassay with Leishmania infantum chagasi antigen. When Leishmania amazonensis antigen was used, 20 (6.1%) samples were positive using ELISA CA and four (1.2%) using IFAT. CONCLUSIONS: There was a low prevalence of infection in the region, and significant differences among the main serological methods used for the diagnosis of leishmaniasis. These findings indicated that the detection of Leishmania spp. requires further study and improvement.

Symbiont modulates expression of specific gene categories in Angomonas deanei

Trypanosomatids are parasites that cause disease in humans, animals, and plants. Most are non-pathogenic and some harbor a symbiotic bacterium. Endosymbiosis is part of the evolutionary process of vital cell functions such as respiration and photosynthesis. Angomonas deanei is an example of a symbiont-containing trypanosomatid. In this paper, we sought to investigate how symbionts influence host cells by characterising and comparing the transcriptomes of the symbiont-containing A. deanei (wild type) and the symbiont-free aposymbiotic strains. The comparison revealed that the presence of the symbiont modulates several differentially expressed genes. Empirical analysis of differential gene expression showed that 216 of the 7625 modulated genes were significantly changed. Finally, gene set enrichment analysis revealed that the largest categories of genes that downregulated in the absence of the symbiont were those involved in oxidation-reduction process, ATP hydrolysis coupled proton transport and glycolysis. In contrast, among the upregulated gene categories were those involved in proteolysis, microtubule-based movement, and cellular metabolic process. Our results provide valuable information for dissecting the mechanism of endosymbiosis in A. deanei.

Combination of the essential oil constituents citral, eugenol and thymol enhance their inhibitory effect on Crithidia fasciculata and Trypanosoma cruzi growth

We analyzed the effect of the combination of citral, eugenol and thymol, respectively the main constituents of essential oils of Cympobogon citratus (DC) Stapf, Poaceae (lemon grass), Syzygium aromaticum (L.) Merr. & L.M. Perry, Myrtaceae (clove) and Thymus vulgaris L., Lamiaceae (thyme), on the proliferation of the trypanosomatids Crithidia fasciculata and Trypanosoma cruzi. The constituents were initially added individually at different concentrations to C. fasciculata cultures to estimate the IC50/24h. Concentrations in a triple combination were about 2 times and 16.5 times lower against C. fasciculata and T. cruzi, respectively, as compared to isolated compounds. Incubation of C. fasciculata with the trypanocydal agent benznidazole did not affect parasite growth at concentrations up to 500 µg/ml, but the IC50 of this drug against T. cruzi was 15.8 µg/ml, a value about 2-5 times higher than that of constituents in the triple combination. Analysis of treated C. fasciculata by scanning electron microscopy showed rounding of the cell body. Our data show that combination of essential oil constituents resulted in increased inhibitory activity on growth of both non-pathogenic and pathogenic trypanosomatid species and indicate that the non-patogenic C. fasciculata may represent a resistant model for drug screening in trypanosomatids.

Cl gene cluster encoding several small nucleolar RNAs: a comparison amongst trypanosomatids

Small nucleolar RNAs (snoRNAs) are small non-coding RNAs that modify RNA molecules such as rRNA and snRNA by guiding 2'-O-ribose methylation (C/D box snoRNA family) and pseudouridylation reactions (H/ACA snoRNA family). H/ACA snoRNAs are also involved in trans-splicing in trypanosomatids. The aims of this work were to characterise the Cl gene cluster that encodes several snoRNAs in Trypanosoma rangeli and compare it with clusters from Trypanosoma cruzi, Trypanosoma brucei, Leishmania major, Leishmania infantum, Leishmania braziliensis and Leptomonas collosoma. The T. rangeli Cl gene cluster is an 801 base pair (bp) repeat sequence that encodes three C/D (Cl1, Cl2 and Cl4) and three H/ACA (Cl3, Cl5 and Cl6) snoRNAs. In contrast to T. brucei, the Cl3 and Cl5 homologues have not been annotated in the Leishmania or T. cruzi genome projects (http//:www.genedb.org). Of note, snoRNA transcribed regions have a high degree of sequence identity among all species and share gene synteny. Collectively, these findings suggest that the Cl cluster could constitute an interesting target for therapeutic (gene silencing) or diagnostic intervention strategies (PCR-derived tools).