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Eukaryotic protein kinases (ePKs) are good medical targets for drug development in different biological systems. ePKs participate in many cellular processes, including the p38 MAPK regulation of homeostasis upon oxidative stress. We propose to assess the role of Smp38 MAPK signaling pathway in Schistosoma mansoni development and protection against oxidative stress, parasite survival, and also to elucidate which target genes have their expression regulated by Smp38 MAPK. After a significant reduction of up to 84% in the transcription level by Smp38 MAPK gene knockdown, no visible phenotypic changes were reported in schistosomula in culture. The development of adult worms was tested in vivo in mice infected with the Smp38 knocked-down schistosomula. It was observed that Smp38 MAPK has an essential role in the transformation and survival of the parasites as a low number of adult worms was recovered. Smp38 knockdown also resulted in decreased egg production, damaged adult worm tegument, and underdeveloped ovaries in females. Furthermore, only ~13% of the eggs produced developed into mature eggs. Our results suggest that inhibition of the Smp38 MAPK activity interfere in parasites protection against reactive oxygen species. Smp38 knockdown in adult worms resulted in 80% reduction in transcription levels on the 10th day, with consequent reduction of 94.4% in oviposition in vitro. In order to search for Smp38 MAPK pathway regulated genes, we used an RNASeq approach and identified 1,154 DEGs in Smp38 knockdown schistosomula. A substantial proportion of DEGs encode proteins with unknown function. The results indicate that Smp38 regulates essential signaling pathways for the establishment of parasite homeostasis, including genes related to antioxidant defense, structural composition of ribosomes, spliceosomes, cytoskeleton, as well as, purine and pyrimidine metabolism pathways. Our data show that the Smp38 MAPK signaling pathway is a critical route for parasite development and may present attractive therapeutic targets for the treatment and control of schistosomiasis.

The gender of cercarial larvae can only be determined using molecular methods. End point PCR methods that amplify repetitive markers on the W chromosome of the female (ZW) parasites have been developed, but sometimes results are ambiguous or incorrect. To more effectively distinguish sexes, and to determine why end point PCR can be incorrect, we quantified the W6 repeat sequence and a specific Z chromosome gene using real-time PCR. The ratio between copy number of W6 and a Z chromosome marker unambiguously identifies gender: females have higher ratios (421-4371) than males (0–21). However, some males have low numbers of W6 elements in their genome, and qPCR demonstrated significantly higher W6/Z marker ratios for male genotypes giving ambiguous end point PCR results compared with males giving clear end point results. The quantitative PCR sexing method developed will be particularly useful where reliable sexing of cercariae is critical, for example when staging genetic crosses.

Praziquantel is the drug of choice for the treatment of schistosomiasis. However, several strains of Schistosoma mansoni are resistant to praziquantel, making it necessary to discover new drugs that might be used for its treatment. With this in mind, the properties of a schistosomicidal ethanolic extract of Garcinia brasiliensis Mart. epicarp, the fractions obtained by partitioning this extract, including the hexane fractions, ethyl acetate fraction, and the aqueous fraction, and the isolated compounds 7-epiclusianone, a major component from these fractions, and fukugetin were tested in vitro on adult worms of S. mansoni. Mortality, damage to membranes, and excretory system activity were observed at 100.0, 50.0, 75.0, and 14.0 µg/mL for the ethanolic extract of G. brasiliensis Mart. epicarp, its hexane fractions, the ethyl acetate fraction, and 7-epiclusianone, respectively. For 7-epiclusianone, these data were confirmed by fluorescent probe Hoechst 33 258 and resorufin. Additionally, the biocidal effect of 7-epiclusianone was even higher than the hexane fractions. Moreover, an inhibitory effect of 7-epiclusianone on the egg laying of female adult S. mansoni worms was observed in cercariae and schistossomula. Thus, 7-epiclusianone is a promising schistosomicidal compound; however, more studies are needed to elucidate its mechanism of toxicity and to evaluate the in vivo activity of this compound.

Long noncoding RNAs (lncRNAs) are transcripts generally longer than 200 nucleotides with no or poor protein coding potential, and most of their functions are also poorly characterized. Recently, an increasing number of studies have shown that lncRNAs can be involved in various critical biological processes such as organism development or cancer progression. Little, however, is known about their effects in helminths parasites, such as Schistosoma mansoni. Here, we present a computational pipeline to identify and characterize lncRNAs from RNA-seq data with high confidence from S. mansoni adult worms. Through the utilization of different criteria such as genome localization, exon number, gene length, and stability, we identified 170 new putative lncRNAs. All novel S. mansoni lncRNAs have no conserved synteny including human and mouse. These closest protein coding genes were enriched in 10 significant Gene Ontology terms related to metabolism, transport, and biosynthesis. Fifteen putative lncRNAs showed differential expression, and three displayed sex-specific differential expressions in praziquantel sensitive and resistant adult worm couples. Together, our method can predict a set of novel lncRNAs from the RNA-seq data. Some lncRNAs are shown to be differentially expressed suggesting that those novel lncRNAs can be given high priority in further functional studies focused on praziquantel resistance.

Vaults are ribonucleoproteins (13 MDa) highly conserved among lower and higher eukaryotes. Their association produces a complex composed of three proteins named Major Vault Protein (MVP), vault (PolyADP-ribose) polymerase (VPARP) and Telomerase-associated protein (TEP1), plus a small untranslated RNA. The exact function of this complex is unknown, although the biological role of vaults has been associated with multidrug resistance phenotypes and signal transduction pathways. Genomic analysis showed that model organisms, such as Caenorhabditis elegans and Drosophila melanogaster, do not possess genes encoding vaults. However, we have found that vault-related genes are present in the Schistosoma mansoni genome. These observations raised questions on the involvement of vaults in mechanisms of adaptation of the parasite in its mammalian host. Therefore, molecular characterisation of the putative Major Vault Protein performed using bioinformatics tools showed that this vault component is highly conserved in S. mansoni. The MVP expression level was quantified by qRT-PCR using total RNA from susceptible (LE) and resistant (LE-PZQ) adult worm lineages, cercariae and mechanically transformed schistosomula (MTS) cultured for 3.5, 24, 48 and 72 h in vitro. Our results suggest a stage-specific expression in all developmental stages analysed. Western blotting has shown up-regulation of SmMVP in the MTS-3.5, 72 h and resistant adult worms, and similar levels in all other stages. Furthermore, SmMVP was found differentially expressed in adult males and females from the susceptible lineage. Further studies should clarify whether SmMVP is somehow linked to drug resistance in S. mansoni.

Schistosomiasis is a neglected disease that affects approximately 200 million people worldwide. In order to reduce the parasite prevalence, further researches aiming new treatment methods is necessary. Once infected by Shistossoma mansoni, one can have no symptoms in the acute phase, however, chronic phase is characterized by marked egg-induced hepatic granulomatous inflammation. To prevent the disease, the main prophylactic method is environmental sanitation which decreases the entrance of eggs into water bodies. In addition to fighting the snail, treatment of population is important. Currently, for treatment of schistosomisasis, the most used drugs are Praziquantel (PZQ) and Oxamniquine, whereas PZQ is the drug of choice. Each drug has a specific mechanism of action aimed at the elimination of the parasite. However, any parasite treatment based on the use of a single drug poses serious concerns regarding the onset of resistance. The search for new therapeutic agents derived from medicinal plants for schistosomiasis has progressed significantly in the last decade. The aim of this paper is to provide an updated survey on medicinal plants that have significant therapeutic effects in animal models of schistosomiasis. A considerable number of herbal constituents with schistosomicidal effect have been well characterized and may be good candidates for prospective studies and investigations that may result in clinical usage. Key words: Schistosoma mansoni, schistosomicidal, medicinal plants.

Eremanthus erythropappus (DC) McLeisch, a plant popularly known as Candeia (Asteraceae), has high therapeutic potential. In this study, the in vitro schistosomicidal potentials of the ethanolic, dichloromethane and hexane extract of branches were evaluated. Couples of worms obtained from the infected mice were cultured in RPMI supplemented with foetal bovine serum and antibiotics. Four pairs of adult worms were exposed to increasing concentrations of each extract and examined by light microscope. The extracts at 100 and 200 µg mL(-1) had schistosomicidal activity, as demonstrated by the analysis of several aspects such as tegument darkening, absence of motility, incapacity of adhesion in culture plate and absence of egg in culture medium. At 50 and 75 µg mL(-1), the dichloromethane and hexane extracts were highly effective. The results suggest that these extracts could be useful in the development of new schistosomicidal drugs.

The aim of this article included the development and evaluation of the capacity of nanoemulsions to improve the activity of the novel schistosomicidal drug-2-(butylamino)-1-phenyl-1-ethanethiosulfuric acid (BphEA). BphEA is a compound with a poor solubility in water, which makes its application as a drug difficult. Nanoemulsion formulations presenting anionic (NANOSTOA, NANOST and NANOLP) and cationic (NANOSTE) interfacial charges were prepared to encapsulate BphEA. These formulations were characterized by the encapsulation rate, diameter, and zeta potential. NANOSTOA, NANOST, and NANOLP presented an entrapment efficiency and zeta potential of 18.7+/-1.8% and -33.6+/-1.2 mV; 20.5+/-3.0% and -31.5+/-5.7 mV; as well as 33.8+/-7.2% and -62.6+/-1.3 mV, respectively. NANOSTE presented an entrapment efficiency of 51.8+/-5.0% and a zeta potential of 25.7+/-3.9 mV. The mean droplet size (between 200 and 252 nm) and polydispersity index (between 0.158 and 0.294) were similar for all formulations. The stability study showed no alteration in these formulations' zeta potential and size. The in vitro schistosomicidal activity of BphEA was higher with the use of NANOSTE than with free BphEA. In addition, release studies revealed a good stability of NANOSTE containing BphEA in a biological medium. These results indicate that cationic nanoemulsions can represent an interesting delivery system for the pharmaceutical formulation of BphEA.

We have been able to label the excretory system of cercariae and all forms of schistosomula, immature and adult worms with the highly fluorescent dye resorufin. We have shown that the accumulation of the resorufin into the excretory tubules and collecting ducts of the male adult worm depends on the presence of extracellular calcium and phosphate ions. In the adult male worms, praziquantel (PZQ) prevents this accumulation in RPMI medium and disperses resorufin from tubules which have been prelabelled. Female worms and all other developmental stages are much less affected either by the presence of calcium and phosphate ions, or the disruption caused by PZQ. The male can inhibit the excretory system in paired female. Fluorescent PZQ localises in the posterior gut (intestine) region of the male adult worm, but not in the excretory system, except for the anionic carboxy fluorescein derivative of PZQ, which may be excreted by this route. All stages of the parasite can recover from damage by PZQ treatment in vitro. The excretory system is highly sensitive to damage to the surface membrane and may be involved in vesicle movement and damage repair processes. In vivo the adult parasite does not recover from PZQ treatment, but what is inhibiting recovery is unknown, but likely to be related to immune effector molecules.

Federal University of Juiz de Fora. Institute of Biological Sciences. Department of Biochemistry. Bioactive Natural Products Laboratory. Juiz de Fora, MG, Brazil Federal University of Juiz de Fora. Institute of Biological Sciences. Department of Biochemistry. Bioactive Natural Products Laboratory. Juiz de Fora, MG, Brazil Federal University of Juiz de Fora. Institute of Biological Sciences. Department of Biochemistry. Bioactive Natural Products Laboratory. Juiz de Fora, MG, Brazil Federal University of Juiz de Fora. Institute of Biological Sciences. Department of Biochemistry. Bioactive Natural Products Laboratory. Juiz de Fora, MG, Brazil Fundação Oswaldo Cruz. Rene Rachou Research Center. Schistosomiasis Laboratory. Belo Horizonte, MG, Brazil Fundação Oswaldo Cruz. Rene Rachou Research Center. Schistosomiasis Laboratory. Belo Horizonte, MG, Brazil Federal University of Juiz de Fora. Institute of Biological Sciences. Department of Morphology. Juiz de Fora, MG, Brazil Federal University of Juiz de Fora. Institute of Biological Sciences. Department of Biochemistry. Protein Structure and Function Study Laboratory. Juiz de Fora, MG, Brazil Federal University of Juiz de Fora. Institute of Biological Sciences. Department of Biochemistry. Protein Structure and Function Study Laboratory. Juiz de Fora, MG, Brazil Federal University of Juiz de Fora. Institute of Biological Sciences. Department of Biochemistry. Bioactive Natural Products Laboratory. Juiz de Fora, MG, Brazil The aims of this work were to evaluate the in vitro and in vivo schistosomicidal properties of the methanolic extract of the aerial parts of Mitracarpus frigidus (MFM) and to determine its HPLC profile. For the in vitro experiment, four pairs of adult worms, obtained from infected mice, were exposed to different concentrations of MFM (100 to 400 g/mL) for 24 and 48 h and analyzed under an inverted microscope. For the in vivo experiment, mice were inoculated with cercariae and, 20 days after infection, MFM (100 and 300mg/kg) was administered orally for the following 25 days. Mice were euthanized after 60 days. MFM showed in vitro schistosomicidal activity, exhibiting the opening of the gynaecophoral canal of some male schistosomes, the presence of contorted muscles, vesicles, and the darkening of the paired worms skin. In vivo experiments showed that MFM treatments significantly reduced total wormcount, as praziquantel, showing a decrease in liver and spleen weight. Also, a significant reduction in granuloma density was observed. MFM treatment did not cause alterations in the liver function of either infected or noninfected mice. The HPLC chromatogram profile showed the presence of kaempferol-O-rutinoside, rutin, kaempferol, psychorubrin, and ursolic acid.

Schistosomiasis is a parasitic disease that, according to the World Health Organization, constitutes a major public health problem associated with severe morbidity, mostly children in preschool age. The administration of drugs in children always constitutes a difficult task, especially when formulations are not developed specifically for pediatric use, when high doses of drug are required and the drug has a bitter taste, as in the case of praziquantel. Polymer nanoparticles are promising systems for development of encapsulated drugs with low water solubility and bitter taste, due to the good physical and chemical stability, adequate biocompatibility and simple manufacturing processes. Moreover, they can enhance the bioavailability and reduce variability of treatment among patients. Poly(methyl methacrylate) doped with praziquantel was produced through a miniemulsion polymerization process to compose a pediatric pharmaceutical suspension. Nanoparticles were characterized in terms of physico-chemical properties, toxicological properties and biological activity in mice, being concluded that obtained results were satisfactory. The results were encapsulation rate around 90%, absence of chemical interaction drug - polymer and the presence of biological activity. A collaborative approach was used for this development, involving national partnerships and independent funding mechanisms, a powerful pathway for development of drugs for neglected diseases. A esquistossomose é uma doença parasitária que, segundo a Organização Mundial da Saúde, é um dos principais problemas de saúde pública associados à morbidade severa, sendo boa parte crianças. A administração de medicamentos em crianças constitui uma tarefa difícil, principalmente quando não há formulações pediátricas, quando altas doses de fármaco são requeridas e o fármaco apresenta um sabor amargo, como é o caso do praziquantel. Nanopartículas poliméricas são sistemas promissores para o desenvolvimento de fármacos com baixa hidrossolubilidade e gosto ruim, apresentam estabilidade físico-química, biocompatibilidade e fáceis processos de produção. Podem ainda proporcionar o aumento da biodisponibilidade e redução da variabilidade do tratamento entre pacientes. O polímero poli(metacrilato de metila) com o praziquantel encapsulado foi sintetizado pelo processo de polimerização em miniemulsão para compor uma suspensão farmacêutica pediátrica. As nanopartículas foram caracterizadas em termos das propriedades físico-químicas, toxicológicas e da atividade biológica em camundongos. Os resultados encontrados foram satisfatórios, taxa de encapsulamento de 90%, ausência de interação química fármaco - polímero e presença de atividade biológica. Uma abordagem colaborativa foi utilizada para este desenvolvimento, envolvendo parcerias nacionais e mecanismos de financiamento independentes, uma maneira nova e poderosa de desenvolver medicamentos para doenças negligenciadas.

A esquistossomose é uma doença parasitária que, segundo a Organização Mundial da Saúde, é um dos principais problemas de saúde pública associados à morbidade severa, sendo boa parte crianças. A administração de medicamentos em crianças constitui uma tarefa difícil, principalmente quando não há formulações pediátricas, quando altas doses de fármaco são requeridas e o fármaco apresenta um sabor amargo, como é o caso do praziquantel. Nanopartículas poliméricas são sistemas promissores para o desenvolvimento de fármacos com baixa hidrossolubilidade e gosto ruim, apresentam estabilidade físico-química, biocompatibilidade e fáceis processos de produção. Podem ainda proporcionar o aumento da biodisponibilidade e redução da variabilidade do tratamento entre pacientes. O polímero poli(metacrilato de metila) com o praziquantel encapsulado foi sintetizado pelo processo de polimerização em miniemulsão para compor uma suspensão farmacêutica pediátrica. As nanopartículas foram caracterizadas em termos das propriedades físico-químicas, toxicológicas e da atividade biológica em camundongos. Os resultados encontrados foram satisfatórios, taxa de encapsulamento de 90%, ausência de interação química fármaco - polímero e presença de atividade biológica. Uma abordagem colaborativa foi utilizada para este desenvolvimento, envolvendo parcerias nacionais e mecanismos de financiamento independentes, uma maneira nova e poderosa de desenvolver medicamentos para doenças negligenciadas.

WorldwideSchistosomiasis mansonicontinues to be a serious public health problem. Over the past decades, control programmes have made remarkable progress in reducingS. mansoniinfections to a relatively low level in Brazil and African countries. Endemic regions are currently circumscribed in certain core areas where reinfection and repeated chemotherapy are frequent and, consequently, are related to residents with low parasite load. At present, diagnosis is predominately a key step for final disease control although low endemicity area residents are hardly detected by most of the available assays. In this paper, we review the current status and efforts made aiming at the improvement of diagnostic tools forS. mansoniin low endemicity infections. The establishment of diagnostic assays—simple, affordable, sensitive, and specific for field diagnosis ofS. mansoni—is essential and should be given high priority.

Schistosomiasis is a parasitic disease that is highly prevalent, especially in developing countries. Biomphalaria tenagophila is an important invertebrate host of Schistosoma mansoni in Brazil, with some strains (e.g. Cabo Frio) being highly susceptible to the parasite, whereas others (e.g. Taim) are completely resistant to infection. Therefore, B. tenagophila is an important research model for studying immune defense mechanisms against S. mansoni. The internal defense system (IDS) of the snail comprises hemocytes and hemolymph factors acting together to recognize self from non-self molecular patterns to eliminate the threat of infection. We performed experiments to understand the cellular defenses related to the resistance and/or susceptibility of B. tenagophila to S. mansoni. During the early stages of infection, fibrous host cells of both snail strains were arranged as a thin layer surrounding the sporocysts. However, at later stages of infection, the cellular reactions in resistant snails were increasingly more intense, with thicker layers surrounding the parasites, in contrast to susceptible strains. All parasites were damaged or destroyed inside resistant snails after 10 h of infection. By contrast, parasites inside susceptible snails appeared to be morphologically healthy. We also performed experiments using isolated hemocytes from the two strains interacting with sporocysts. Hemocyte attachment started as early as 1 h after initial infection in both strains, but the killing of sporocysts was exclusive to hemocytes from the resistant strain and was time course dependent. The resistant strain was able to kill all sporocysts. In conclusion, our study revealed important aspects of the initial process of infection related to immune defense responses of strains of B. tenagophila that were resistant to S. mansoni compared with strains that were susceptible. Such information is relevant for the survival or death of the parasites and so is important in the development of control measures against this parasite.

Human infection bySchistosoma mansoniaffects more than 100 million people worldwide, most often in populations of developing countries of Africa, Asia, and Latin America. The transmission ofS. mansoniin human populations depends on the presence of some species ofBiomphalariathat act as an intermediate host. The compatibility betweenS. mansoniand its intermediate host is influenced by behavioral, physiological, and genetical factors of the mollusc and the parasite. The susceptibility level of the mollusc has been attributed to the capacity of internal defense system (IDS)—hemocytes and soluble components of the hemolymph—to recognize and destroy the parasite, and this will be the center of interest of this paper. The schistosome-resistantBiomphalariacan be an alternative strategy for the control of schistosomiasis.

The outcome of the interaction between Biomphalaria and Schistosoma mansoni depends on the response of the host internal defence system (IDS) and the escape mechanisms of the parasite. The aim of this study was to evaluate the responsiveness of the IDS (haemocytes and soluble haemolymph factors) of resistant and susceptible Biomphalaria tenagophila lineages and Biomphalaria glabrata lineages in the presence of in vitro-transformed primary sporocysts and secondary sporocysts obtained from infected B. glabrata. To do this, we assayed the cellular adhesion index (CAI), analysed viability/mortality, used fluorescent markers to evaluate the tegumental damage and transplanted secondary sporocysts. B. tenagophila Taim was more effective against primary and secondary sporocystes than the susceptible lineage and B. glabrata. Compared with secondary sporocysts exposed to B. tenagophila, primary sporocysts showed a higher CAI, a greater percentage of dead sporocysts and were labelled by lectin from Glycine max and Alexa-Fluor 488 fluorescent probes at a higher rate than the secondary sporocysts. However, the two B. tenagophila lineages showed no cercarial shedding after inoculation with secondary sporocysts. Our hypothesis that secondary sporocysts can escape the B. tenagophila IDS cannot be confirmed by the transplantation experiments. These data suggest that there are additional mechanisms involved in the lower susceptibilty of B. tenagophila to S. mansoni infection.

To elucidate the mechanisms of antischistosoma resistance, drug-resistant Schistosoma mansoni laboratory isolates are essential. We developed a new method for inducing resistance to praziquantel (PZQ) using successive drug treatments of Biomphalaria glabrata snails infected with S. mansoni. Infected B. glabrata were treated three times with 100 mg/kg PZQ for five consecutive days with a one-week interval between them. After the treatment, the cercariae (LE-PZQ) produced from these snails and the LE strains (susceptible) were used to infect mice. Forty-five days after infection, mice were treated with 200, 400 or 800 mg/kg PZQ. Thirty days post-treatment, we observed that the mean number of worms recovered by perfusion was significantly higher in the group of mice infected with the LE-PZQ isolate treated with 200 and 400 mg/kg in comparison to the LE strain with the same treatment. Moreover, there was a significant difference between the ED50 (effective dose required to kill 50% of the worms) of the LE-PZQ isolate (362 mg/kg) and the LE strain (68 mg/kg). In the in vitro assays, the worms of the LE-PZQ isolate were also less susceptible to PZQ. Thus, the use of infected snails as an experimental model for development of resistance to S. mansoni is effective, fast, simple and cheap.

Here, we observed the uptake of membrane-impermeant molecules by cercariae as they penetrate the skin and are transformed into schistosomula. We propose that membrane-impermeant molecules, Lucifer Yellow, Propidium iodide and Hoechst 33258 enter the parasite through both thenephridiopore and the surface membrane and then diffuse throughout the body of the parasite. We present a hypothesis that the internal cells of the body of the schistosomulum represent a new host-parasite interface, at which skin-derived growth factors may stimulate receptors on internal membranes during transformation of the cercariae into the schistosomulum.

SUMMARYThe use of chemotherapy on a mass scale in endemic areas may lead to the appearance of resistant isolates through the mechanism of selective drug pressure. Studies have demonstrated that praziquantel (PZQ) is able to inhibit the excretory activity and to cause tegumental damage inSchistosoma mansoniadult worms. The use of the probe resorufin to evaluate excretory activity, as well as the probe Hoechst 33258 to detect tegumental damage in adult worms, may represent a method to identify resistant (or less susceptible) isolates. The purpose of the present work was to compare the changes caused by PZQ in the function of the excretory system and in the integrity of the tegument of adult worms from the LE isolate (susceptible to PZQ) and the LE-PZQ isolate (less susceptible to PZQ). Worms from the isolate LE-PZQ showed less severe tegumental lesions, in bothin vitroandin vivoexperiments, detected by labelling with Hoechst 33258 and continued to have a functional excretory system as shown by labelling with resorufinin vitro.

Schistosomiasis is a water-borne parasitic illness caused by neoophoran trematodes of the genus Schistosoma. Using classical histological techniques and whole-mount preparations, the present work describes the embryonic development of Schistosoma mansoni eggs in the murine host and compares it with eggs maintained under in vitro conditions. Two pre-embryonic stages occur inside the female worm: the prezygotic stage is characterized by the release of mature oocytes from the female ovary until its fertilization. The zygotic stage encompasses the migration of the zygote through the ootype, where the eggshell is formed, to the uterus. Fully formed eggs are laid still undeveloped, without having suffered any cleavage. In the outside environment, eight embryonic stages can be defined: stage 1 refers to early cleavages and the beginning of yolk fusion. Stage 2 represents late cleavage, with the formation of a stereoblastula and the onset of outer envelope differentiation. Stage 3 is defined by the elongation of the embryonic primordium and the onset of inner envelope formation. At stage 4, the first organ primordia arise. During stages 5 to 7, tissue and organ differentiation occurs (neural mass, epidermis, terebratorium, musculature, and miracidial glands). Stage 7 is characterized by the nuclear condensation of neurons of the central neural mass. Stage 8 refers to the fully formed larva, presenting muscular contraction, cilia, and flame-cell beating. This staging system was compared to a previous classification and could underlie further studies on egg histoproteomics (morphological localizome). The differentiation of embryonic structures and their probable roles in granulomatogenesis are discussed herein.

The activity of lovastatin associated with oxamniquine or praziquantel against schistosomiasis mansoni was evaluated in mice infected with Schistosoma mansoni. Forty days after infection, mice were treated with lovastatin, 400 mg/kg for five consecutive days by oral route, and on the last day of this sequence with 50 mg/kg oxamniquine or with 200 mg/kg praziquantel, both by oral route, single dose. Fifteen days later, the animals were perfused in parallel with an untreated control group. Studies were carried out in vitro, using lovastatin in culture medium containing S. mansoni worms proceeding from experimentally infected mice. In the in vivo trials, the association of lovastatin with oxamniquine or praziquantel did not show any additive action, but there were oogram changes when lovastatin was associated with oxamniquine. In vitro lovastatin was able to interrupt the maturation of S. mansoni eggs, which remained at the 1st or 2nd stages, depending on the dose used. The total number of morphologically dead eggs found in culture of worms exposed to 2 microg/ml or 4 microg/ml concentrations of lovastatin was significantly higher than the number of viable eggs. Using the probe Hoescht 33258 it was observed that 70% of the eggs considered morphologically viable in the treated groups (against 16% in the control group) were labeled, indicating that the majority of the viable eggs had membrane permeability increased due to lovastatin action.

The activity of oxamniquine (OXA), praziquantel (PZQ), and a combination of both drugs was evaluated at the intramolluscan phase of Schistosoma mansoni. Biomphalaria glabrata snails infected with S. mansoni were treated with 500 mg/kg OXA, 1000 mg/kg PZQ or with 250 mg/kg OXA and 500 mg/kg PZQ, in association, at the pre-patent and patent phases of infection. The results showed that either treatments with OXA or PZQ, alone, at the pre-patent period, delayed the parasite's development, increasing the pre-patent period by approximately 10 days. At the same pre-patent period, treatment with a combination of OXA/PZQ delayed the parasite's development even more, extending the pre-patent period up to 56 days. At the patent period, treatment with OXA and PZQ, alone, interrupted cercarial shedding. When the snails were treated with 1000 mg/kg PZQ, the cercarial production was re-established 15 days after treatment, but in lower numbers than those obtained before treatment, whereas the snails treated with 500 mg/kg OXA were able to shed cercariae in similar quantities to those observed before treatment. The association 250 mg/kg OXA+500 mg/kg PZQ, at the patent period, not only discontinued cercarial shedding, but also led to the "cure" of the snails, showing a synergistic effect of this combination of drugs. These results suggest that this model will be useful for selection of resistant parasites, as well as for screening new antischistosomal drugs.

A esquistossomose mansoni é uma das principais doenças parasitárias no mundo, sendo provocada por trematódeo da espécie Schistosoma mansoni, o qual possui caramujos do gênero Biomphalaria como hospedeiros invertebrados. No Brasil, Biomphalaria tenagophila é o segundo mais importante hospedeiro, apresentando linhagens altamente suscetíveis ao parasito e outras absolutamente resistentes. A natureza da resistência e suscetibilidade de B. tenagophila não é completamente esclarecida, mas admite-se que os hemócitos, células efetoras do sistema interno de defesa dos moluscos, desempenham papel crucial na contenção da infecção. Assim, o estudo expressão proteica pelos hemócitos em resposta à infecção por S. mansoni pode gerar informações relevantes que contribuam para a melhor compreensão de aspectos da interação parasito-hospedeiro. Este estudo comparou os perfis proteômicos de hemócitos da hemolinfa de populações de B. tenagophila resistentes (Taim/RS e Anchieta/ES) e suscetível (Cabo Frio/RJ), desafiadas ou não por S. mansoni. Através do DIGE e eletroforese bidimensional os perfis proteicos das três populações antes e após o desafio foram avaliados e, posteriormente, as proteínas diferencialmente expressas foram identificadas por espectrometria de massa. Foi possível observar proteínas com expressão alterada entre populações resistentes e suscetíveis, principalmente após a exposição a S. mansoni. Na população de Taim desafiada foi observada expressão aumentada de um componente da família das proteínas que contem tioéster (TEP) que é relacionada à fagocitose ou encapsulação de patógenos, bem como da proteína hipotética LOTGIDRAFT_234865 envolvida com a ligação e transporte de um produto resultante da formação de espécies reativas de oxigênio. O aumento da expressão de HSP70 e de frutose-bisfosfato aldolase em Cabo Frio desafiada pode estar relacionada com o fenótipo suscetível desta linhagem. A identificação das proteínas e a análise nos bancos de dados foram afetadas pela ausência do genoma completo de B. glabrata. Ainda assim, os resultados encontrados foram significativos e confirmaram a já conhecida complexidade da interação molecular entre Biomphalaria e S. mansoni. Schistosomiasis mansoni remains one of the main parasitic diseases in the world and is caused by a trematode of the species Schistosoma mansoni, whose invertebrate hosts are molluscs of the genus Biomphalaria. Biomphalaria tenagophila is an important host in Brazil, with some strains being highly susceptible to the parasite, whereas others are absolutely resistant to infection. The nature of the resistance and susceptibility of B. tenagophila is not completely understood, but it is assumed that the hemocytes, effector cells of molluscs internal defense system, play a crucial role in controlling trematode infections. Thus, the study of proteins produced by hemocytes in response to infection by S. mansoni can generate relevant contributions to a better understanding of host-parasite interaction. This study compared the proteomic profiles of hemocytes from the hemolymph of resistant B. tenagophila populations (Taim / RS and Anchieta / ES) and a susceptible one (Cabo Frio / RJ), challenged or not with S. mansoni. Through the two-dimensional electrophoresis and DIGE the protein profiles of the three populations before and after challenge were evaluated and then differentially expressed proteins were identified by mass spectrometry. The findings showed proteins with altered expression between resistance and susceptibility phenotypes, especially after exposure to S. mansoni. In the Taim challenged population, it was observed an elevation of two relevant proteins: a member of the thioester-containing proteins (TEP) family, which is related to phagocytosis or encapsulation of pathogens; and a hypothetical protein LOTGIDRAFT_234865 involved in binding and transport of a product of reactive oxygen species formation. Increased HSP70 and fructose-bisphosphate aldolase expression in Cabo Frio challenged may be related to this strain susceptible phenotype. The absence of the complete B. glabrata genome affected proteins identification and database analysis. Nevertheless, results were significant and confirmed the already known complexity of the molecular interaction between Biomphalaria and S. mansoni.