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Background Most cystic echinococcosis cases in Southern Brazil are caused by Echinococcus granulosus and Echinococcus ortleppi. Proteomic studies of helminths have increased our knowledge about the molecular survival strategies that are used by parasites. Here, we surveyed the protein content of the hydatid fluid compartment in E. granulosus and E. ortleppi pulmonary bovine cysts to better describe and compare their molecular arsenal at the host-parasite interface. Methods Hydatid fluid samples from three isolates of each species were analyzed using mass spectrometry-based proteomics (LC-MS/MS). In silico functional analyses of the identified proteins were performed to examine parasite survival strategies. Results The identified hydatid fluid protein profiles showed a predominance of parasite proteins compared to host proteins that infiltrate the cysts. We identified 280 parasitic proteins from E. granulosus and 251 from E. ortleppi, including 52 parasitic proteins that were common to all hydatid fluid samples. The in silico functional analysis revealed important molecular functions and processes that are active in pulmonary cystic echinococcosis, such as adhesion, extracellular structures organization, development regulation, signaling transduction, and enzyme activity. Conclusions The protein profiles described here provide evidence of important mechanisms related to basic cellular processes and functions that act at the host-parasite interface in cystic echinococcosis. The molecular tools used by E. granulosus and E. ortleppi for survival within the host are potential targets for new therapeutic approaches to treat cystic echinococcosis and other larval cestodiases. Graphical Abstract

Genetic diversity is one of the most important issues in studies on conservation of cattle breeds and endangered species. The objective of this study was to estimate the levels of genetic differentiation between locally adapted taurine (Bos taurus taurus) and zebu (Bos taurus indicus) breeds in Brazil, which were genotyped for more than 777,000 SNPs. The fixation index (F ST), principal component analysis (PCA), and Bayesian clustering were estimated. The F ST highlighted genetic differentiation between taurine and zebu breeds. The taurine lines, Caracu and Caracu Caldeano, had significant genetic differentiation (F ST close to 5%) despite their recent selection for different uses (meat and milk). This genetic variability can be used for conservation of locally adapted animals, as well as for breeding programs on zebu breeds. Introgression of zebu in locally adapted breeds was identified, especially in Curraleiro Pe-Duro breed. The Gyr breed, however, had low breed purity at genomic level due to its very heterogeneous mixing pattern.

Background In conditions of immunosuppression, the central nervous sty 5ystem (CNS) is the main target tissue for the reactivation of infection by Trypanosoma cruzi, the causative agent of Chagas disease. In experimental T. cruzi infection, interferon gamma (IFNγ)+ microglial cells surround astrocytes harboring amastigote parasites. In vitro, IFNγ fuels astrocyte infection by T. cruzi, and IFNγ-stimulated infected astrocytes are implicated as potential sources of tumor necrosis factor (TNF). Pro-inflammatory cytokines trigger behavioral alterations. In T. cruzi-infected mice, administration of anti-TNF antibody hampers depressive-like behavior. Herein, we investigated the effects of TNF on astrocyte susceptibility to T. cruzi infection and the regulation of cytokine production. Methods Primary astrocyte cultures of neonatal C57BL/6 and C3H/He mice and the human U-87 MG astrocyte lineage were infected with the Colombian T. cruzi strain. Cytokine production, particularly TNF, and TNF receptor 1 (TNFR1/p55) expression were analyzed. Recombinant cytokines (rIFNγ and rTNF), the anti-TNF antibody infliximab, and the TNFR1 modulator pentoxifylline were used to assess the in vitro effects of TNF on astrocyte susceptibility to T. cruzi infection. To investigate the role of TNF on CNS colonization by T. cruzi, infected mice were submitted to anti-TNF therapy. Results rTNF priming of mouse and human astrocytes enhanced parasite/astrocyte interaction (i.e., the percentage of astrocytes invaded by trypomastigote parasites and the number of intracellular parasite forms/astrocyte). Furthermore, T. cruzi infection drove astrocytes to a pro-inflammatory profile with TNF and interleukin-6 production, which was amplified by rTNF treatment. Adding rTNF prior to infection fueled parasite growth and trypomastigote egression, in parallel with increased TNFR1 expression. Importantly, pentoxifylline inhibited the TNF-induced increase in astrocyte susceptibility to T. cruzi invasion. In T. cruzi-infected mice, anti-TNF therapy reduced the number of amastigote nests in the brain. Conclusions Our data implicate TNF as a promoter of T. cruzi invasion of mouse and human astrocytes. Moreover, the TNF-enriched inflammatory milieu and enhanced TNFR1 expression may favor TNF signaling, astrocyte colonization by T. cruzi and egression of trypomastigotes. Therefore, in T. cruzi infection, a self-sustaining TNF-induced inflammatory circuit may perpetuate the parasite cycle in the CNS and ultimately promote cytokine-driven behavioral alterations. Electronic supplementary material The online version of this article (doi:10.1186/s12974-017-0952-0) contains supplementary material, which is available to authorized users.

Despite the fact that cestodes represent major etiological agents of both human and domestic animal diseases, little is known about the molecular aspects of cestode development. In this work, Mesocestoides corti, a model cestode species, was studied from the early development of its larval form (tetrathyridium) into adult worms (strobilation) using different proteomic approaches. The protein profiles of M. corti tetrathyridia induced or not induced to undergo strobilation were compared. Proteomic mapping by two-dimensional gel electrophoresis showed the resolution of 248 and 154 spots from tetrathyridia that were subjected or not subjected to strobilation induction, respectively, allowing for the detection of at least nine spots exclusive to each group. Spot analysis by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) or MALDI-TOF MS/MS identified four reference proteins (six spots). LC-MS/MS analyses of protein extracts identified 66 proteins, eight of which were found exclusively in non-induced tetrathyridia, while 13 were found exclusively in strobilation-induced tetrathyridia. Among the proteins exclusively identified in strobilation-induced worms, there was a predominance of proteins with functions relating to chaperone activity and protein synthesis and turnover. Quantitative differential expression analysis between M. corti tetrathyridia prior to and after strobilation induction revealed six proteins upregulated in strobilation-induced worms; these proteins were involved in metabolic pathways, cell proliferation, and cytoskeletal rearrangement. Overall, despite the absence of a sequenced M. corti genome, using sequences from other platyhelminthes, we were able to establish comprehensive protein profiles for tetrathyridia prior to and after strobilation induction and identify several proteins potentially involved in the early events leading to strobilation.

Tritrichomonas foetus is an amitochondriate parasite that possesses hydrogenosomes, unusual anerobic energy-producing organelles. In these organisms the "mitochondrial cell death machinery" is supposed to be absent, and the mechanisms that lead to cell demise remain to be elucidated. The presence of a cell death program in trichomonads has already been reported, suggesting the existence of a caspase-like execution pathway in such organisms. Here we demonstrate the alterations provoked by the fungicide griseofulvin and raise the possibility that other cell death pathways may exist in T. foetus. Dramatic changes in trichomonads morphology are presented after griseofulvin treatment, such as intense plasma membrane and nuclear envelope blebbing, nucleus fragmentation, and an abnormal number of oversized vacuoles. One important finding was the exposition of phosphatidylserine (PS) in the outer leaflet of the plasma membrane in cells after drug treatment, and also the presence of a high amount of misshapen flagella and tubulin precipitates as vacuolar contents, suggesting an autophagic process of abnormal cellular elements. Interestingly, immunoreactivity for activated caspase-3 was not detected during griseofulvin treatment, a finding distinct from the observed when this cell was treated with H(2)O(2). The possibility of the existence of different pathways to cell death in trichomonads is discussed.

Tritrichomonas foetus is a parasitic protist of the urogenital tract of cattle. It presents the trophozoite stage, a motile elongated form that constitutes most of the cells in a normal population, and a pseudocyst stage, an immotile rounded form that appears under unfavourable environmental conditions. In the present report pseudocysts were studied in natural conditions and after induction by chemicals or cycles of cooling and warming of cultures. The capacity of T. foetus to adhere to vaginal epithelial cells (VECs) was compared for both trophozoite and pseudocyst forms. By the use of video-enhanced-contrast microscopy, scanning and transmission electron microscopy, and immunofluorescence microscopy techniques, we present evidence that: (1) T. foetus easily internalizes the flagella and forms pseudocysts under several unfavourable conditions; (2) T. foetus in both pseudocyst and trophozoite forms is able to adhere to VECs; (3) the adhesion rate is higher for pseudocysts than for trophozoites; (4) the adhesin Tf190 is expressed in both forms during interaction; (5) the adhesion process of pseudocysts seems to occur in a contact-dependent manner. Thus, we propose that the pseudocyst stage is not a degenerative form, but a functional life form that is able to interact with and firmly adhere to VECs.

Tritrichomonas foetus is an amitochondrial parasite protist which lacks typical eukaryote organelles such as mitochondria and peroxisomes, but possesses the hydrogenosome, a double-membrane-bound organelle that produces ATP. The cell death of amitochondrial organisms is poorly studied. In the present work, the cytotoxic effects of hydrogen peroxide on T. foetus and its participation on cell death were analyzed. We took advantage of several microscopy techniques, including videomicroscopy, light microscopy immunocytochemistry for detection of caspase activation, and scanning and transmission electron microscopy. We report here that in T. foetus: (1) H(2)O(2) leads to loss of motility and induces cell death, (2) the dying cells exhibit some characteristics similar to those found during the death of other organisms, and (3) a caspase-like protein seems to be activated during the death process. Thus, we propose that, although T. foetus does not present mitochondria nor any known pathways of cell death, it is likely that it bears mechanisms of cell demise. T. foetus exhibits morphological and physiological alterations in response to H(2)O(2) treatment. The hydrogenosome, a unique organelle which is supposed to share a common ancestral origin with mitochondria and has an important role in oxidative responses in trichomonads, is a candidate for participating in this event.