Metabolic disruptions in Biomphalaria glabrata induced by Heterorhabditis bacteriophora HP88: Implications for entomopathogenic nematodes in biological control.

Research on the use of entomopathogenic nematodes (EPNs) as a potential tool for the biological control of invertebrates has been growing in recent years, including studies involving snails with One Health importance. In this study, the effect of exposure time (24 or 48 h) of Heterorhabditis bacteriophora HP88 on the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as well as the concentration of total proteins, uric acid, and urea in the hemolymph of Biomphalaria glabrata, were investigated. The concentrations of these metabolic markers were measured weekly until the end of the third week after exposure. Along with a significant reduction in total protein levels, a significant increase (p < 0.01) in uric acid and urea contents in the hemolymph of B. glabrata exposed to H. bacteriophora was observed. The accumulation of urea in these mollusks could lead to deleterious effects due to its high toxicity, inducing significant cell damage. Variations in transaminase activities were also observed, with snails exposed to EPNs showing significantly higher values (p < 0.01) than individuals in the control group, both for ALT and AST. These results indicate that experimental exposure to infective juveniles of H. bacteriophora causes significant alterations in the metabolic pattern of B. glabrata, compromising the maintenance of its homeostasis. Finally, exposure for 48 h caused more damage to the planorbid in question compared to snails exposed for 24 h, suggesting that the exposure time may influence the intensity of the host's response.

Destruction of Schistosoma mansoni sporocysts in Biomphalaria glabrata after phytochemical exposure.

Schistosomiasis is a neglected tropical disease and affects over 200 million people worldwide. The snail Biomphalaria glabrata is one of the intermediate hosts of S. mansoni. The aim of this work was to verify the action of Euphorbia milii var. hislopii latex in the hemocytes profile and histopathology of B. glabrata infected by S. mansoni. Uninfected and infected snails were exposed to sublethal concentration of E. milii latex for 24 hours (1.0 mg/L). The survival rate was 88.5% for the uninfected snails and 66.6% for the infected and exposed snails. In the snails infected by S. mansoni, the exposure to E. milii latex promoted proliferation of hemocytes in the tentacles, mantle, digestive gland and kidney. In the digestive gland and the kidney, granulomatous reactions occurred around the sporocysts and caused their destruction. The number of circulating hemocytes from the group infected and exposed to E. milii latex was significantly higher than in the other groups. Three types of hemocytes were found: hyalinocytes, granulocytes and blast-like cells. We conclude that the E. milii latex influenced the cellular immune response of the susceptible B. glabrata strain to infection by S. mansoni, promoting the destruction of parasites.

Detection of Schistosoma mansoni long non-coding RNAs in the infected C57BL/6 mouse liver.

Long non-coding RNAs (lncRNAs) perform several types of regulatory functions and have been recently explored in the genus Schistosoma. Although sequencing and bioinformatics approaches have demonstrated the presence of hundreds of lncRNAs and microRNAs (miRNAs) in this genus, information regarding their abundance, characteristics, and potential functions linked to Schistosoma mansoni biology and parasite-host interaction is limited. Our objectives in the present study were to verify whether 15 previously identified S. mansoni lncRNAs are detectable in the host liver. In addition, we assess whether these lncRNAs are present in the S. mansoni infective form and the stages inside the definitive host. The detection of these 15 S. mansoni lncRNAs and a long terminal repeat (LTR) retrotransposon Saci 4 was performed in the eggs, cercariae, and 3.5-h schistosomula. All lncRNAs were found to be expressed in these stages; some of the lncRNAs were found in the livers of the infected C57BL/6 mice. In conclusion, S. mansoni lncRNAs were detected in host livers and quantified. Furthermore, many of the lncRNAs analyzed showed differential expression in the larval stages, indicating that they play a stage-specific regulatory role.

Differential expression profiles of miRNAs and their putative targets in Schistosoma mansoni during its life cycle.

BACKGROUND: Schistosomiasis is a disease caused by Schistosoma. Due to its complex life cycle, evolutionary position and sexual dimorphism, schistosomes have several mechanisms of gene regulation. MicroRNAs (miRNAs) are short endogenous RNAs that regulate gene expression at the post-transcriptional level by targeting mRNA transcripts. OBJECTIVES: Here, we tested 12 miRNAs and identified their putative targets using a computational approach. METHODS: We performed the expression profiles of a set of miRNAs and their putative targets during the parasite's life cycle by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). FINDINGS: Our results showed differential expression patterns of the mature miRNAs sma-miR-250; sma-miR-92a; sma-miR-new_4-3p; sma-miR-new_4-5p; sma-miR-new_5-5p; sma-miR-new_12-5p; sma-miR-new_13-3p and sma-miR-new_13-5p. Interestingly, many of the putative target genes are linked to oxidative phosphorylation and are up-regulated in adult-worms, which led us to suggest that miRNAs might play important roles in the post-transcriptional regulation of genes related to energetic metabolism inversion during parasite development. It is noteworthy that the expression of sma-miR-new_13-3p exhibited a negative correlation on SmNADH:ubiquinone oxidoreductase complex I. MAIN CONCLUSIONS: Our analysis revealed putative miRNA genes related to important biological processes, such as transforming growth factor beta (TGF-ß) signaling, proteasome regulation, glucose and lipid metabolism, immune system evasion and transcriptional regulation.

Evaluation of changes in the carbohydrate metabolism of Biomphalaria glabrata Say, 1818 exposed to experimental coinfection by Angiostrongylus cantonensis (Nematoda) and Echinostoma paraensei (Trematoda).

The interaction between intermediate snail hosts and helminths can cause metabolic changes in the former. The snails use their reserves for maintenance of their vital processes, by activating the internal defense system and repairing tissue damage, while also supplying necessary energy for the parasites' development. Our aims were to evaluate the lactate dehydrogenase activity and the glucose concentration in the hemolymph of Biomphalaria glabrata experimentally coinfected by Angiostrongylus cantonensis and Echinostoma paraensei. Besides these aspects, the glycogen content in the digestive gland complex and cephalopedal mass along with histochemical changes in parasitized snails were analyzed. The snails were divided in group A (infected by 1200 L1 of A. cantonensis), group E (infected by 20 E. paraensei miracidia), group A + E (co-infected with A. cantonensis first and after a week by E. paraensei), group E + A (co-infected with E. paraensei first and then by A. cantonensis) and control group (not infected). During four weeks after exposure, samples were collected for biochemical and histochemical analyses. In the infected snails, glucose levels and glycogen content in the digestive gland complex and cephalopedal mass were significantly lower, in contrast with an increase of lactate dehydrogenase activity. These results indicate that the intense energy demand resulting from the presence of parasites causes the host snail to accelerate the anaerobic degradation of carbohydrates to obtain energy, in an attempt to maintain homeostasis. Both parasites were observed in histochemical analysis to cause tissue damages in the snails. So, although the snails were able to sustain the coinfection, several metabolic and tissue changes occurred, mainly in those infected with E. paraensei and then with A. cantonensis.

Three new species of Eimeria Schneider 1875 in the montane grass mouse, Akodon montensis (Rodentia: Cricetidae: Sigmodontinae), and redescription of Eimeria zygodontomyis Lainson and Shaw 1990 from southeastern Brazil.

We describe three new coccidian species of the genus Eimeria Schneider 1875 (Apicomplexa: Eimeriidae) and redescribe and report Eimeria zygodontomyis Lainson and Shaw, 1990 in the montane grass mouse, Akodon montensis Thomas, 1913 from the Serra dos Órgãos National Park in southeastern Brazil. Sporulated oocysts of Eimeria zygodontomyis are ellipsoidal to cylindrical with a 0.6 (0.5-0.8) µm thick very delicate bi-layered wall; length × width (n = 49) 18.3 × 12.5 (16-20 × 11-13) µm; length/width ratio of 1.4 (1.2-1.6); 1 polar granule occasionally present; micropyle, residuum both absent. Sporocysts are ellipsoidal; length × width 8.5 × 5.2 (8-11 × 5-6) µm; length/width ratio of 1.5 (1.3-1.7) µm; Stieda body is prominent; sub-Stieda body is absent; sporocyst residuum is compact. Sporulated oocysts of Eimeria montensis n. sp. are spheroidal to subspheroidal with a 1.2 (1.0-1.4) µm thick bi-layered wall; outer layer lightly pitted; length × width (n = 30) 16.3 × 12.5 (15-17 × 13-15) µm; length/width ratio of 1.3 (1.0-1.4); 1 polar granule present; micropyle, residuum both absent. Sporocysts are ellipsoidal; length × width 7.2 × 5.1 (6-8 × 4-6) µm; length/width ratio of 1.4 (1.2-1.6); Stieda body is present, sub-Stieda body is absent; sporocyst residuum consists of small, scattered granules. Sporulated oocysts of Eimeria uricanensis n. sp. are ovoidal to pyriform with a 1.4 ( 1.3-1.6) µm thick bi-layered wall; outer layer lightly pitted; length × width (n = 40) 26.6 × 18.6 (23-30 × 17-20) µm; length/width ratio of 1.4 (1.3-1.6); 1 polar granule present; micropyle, residuum both absent. Sporocysts are ellipsoidal, length × width 13.3 × 8.0 (10-16 × 7-9) µm; length/width ratio of 1.7 (1.5-1.9); Stieda body, sub-Stieda body both absent; sporocyst residuum consists of a cluster of granules, forming a spheroid mass. Sporulated oocysts of Eimeria parnasiensis n. sp. are subspheroidal to ellipsoidal with a 1.8 ( 1.3-2.4) µm thick bi-layered wall; outer layer lightly pitted; length × width (n = 54) 28.2 × 21.9 (26-32 × 19-28) µm; length/width ratio of 1.3 (1.2-1.4); 1 polar granule present; micropyle is absent; oocyst residuum is present and consists of a cluster of granules of varying thickness. Sporocysts are ovoidal, tapering towards the Stieda body; length × width 12.2 × 7.6 (10-13 × 6-9) µm; length/width ratio of 1.6 (1.4-1.9); Stieda body is present; sub-Stieda body is absent; sporocyst residuum is present and consists of an aggregate of thin granules.

Biological and histological changes in reproductive patterns of Biomphalaria glabrata experimentally co-infected by Echinostoma paraensei and Angiostrongylus cantonensis.

Investigation of co-infection by different helminths in snails can provide essential information about the biology of parasites co-existence under natural conditions. This study aimed to investigate the reproductive and histological changes of Biomphalaria glabrata experimentally co-infected with Echinostoma paraensei and Angiostrongylus cantonensis. Five groups of snails i.e. uninfected, with single and double infections, either E. paraensei first (E + A) or A. cantonensis first (A + E) were followed; three times a week during four weeks the numbers of egg masses, eggs and hatched snails were counted. Histological analysis of the ovotestis and albumen gland was performed after four weeks. The number of egg masses/snail, eggs/snail and hatched snails showed significative differences comparing the control group to all infected groups, especially in group E + A, with the majority of values of parameters analyzed lower than 50% of those observed for control snails. In addition, the mortality was higher in the group E + A than to control group. The histological analysis showed that presence of both parasites in the reproductive organs was associated with tissue damages.

A new species of Eimeria Schneider, 1875 from the Serra dos Órgãos National Park, Rio de Janeiro, Brazil, with notes on its endogenous development in the montane grass mouse, Akodon montensis Thomas, 1913 (Rodentia: Sigmodontinae).

A total of 53 specimens of the montane grass mouse, Akodon montensis Thomas, 1913 were collected in the Serra dos Órgãos National Park (SONP) in November 2014 and July 2015. The fecal material was analyzed, and a prevalence of 7.5% was recorded for a new coccidian species of the genus Eimeria Schneider, 1875, with part of its endogenous development recorded in the small intestine. The oocysts of a new coccidian species of genus Eimeria are ellipsoidal to subspherical. The wall is bi-layered, c. 1.5 µm (1.3-1.6 µm) thick, outer layer rough. Oocyst (n = 126) mean length is 25.3 µm (21.0-28.0 µm), with a width of 20.2 µm (17.0-22.0 µm) and mean length/width (L:W) ratio of 1.3 (1.2-1.4). Polar granule is present, with the oocyst residuum as a large spherical to subspherical globule. Sporocyst shape (n = 126) is ellipsoidal, with a mean length of 11.8 µm (9.3-14.4 µm), width of 7.9 µm (6.7-9.3 µm), and mean L:W ratio of 1.5 (1.4-1.7). Sporocysts with nipple-like Stieda body and sub-Stieda body are absent. A sporocyst residuum formed by several globules, usually along the sporocyst wall. This is the first record of Eimeria in the montane grass mouse from Brazil.

Characterisation of the vascular pathology in Sigmodon hispidus (Rodentia: Cricetidae) following experimental infection with Angiostrongylus costaricensis (Nematoda: Metastrongylidae).

BACKGROUND: Angiostrongylus costaricensis is a nematode that causes human abdominal angiostrongyliasis, a disease found mainly in Latin American countries and particularly in Brazil and Costa Rica. Its life cycle involves exploitation of both invertebrate and vertebrate hosts. Its natural reservoir is a vertebrate host, the cotton rat Sigmodon hispidus. The adult worms live in the ileo-colic branches of the upper mesenteric artery of S. hispidus, causing periarteritis. However, there is a lack of data on the development of vasculitis in the course of infection. OBJECTIVE: To describe the histopathology of vascular lesions in S. hispidus following infection with A. costaricensis. METHODS: Twenty-one S. hispidus were euthanised at 30, 50, 90 and 114 days post-infection (dpi), and guts and mesentery (including the cecal artery) were collected. Tissues were fixed in Carson's Millonig formalin, histologically processed for paraffin embedding, sectioned with a rotary microtome, and stained with hematoxylin-eosin, resorcin-fuchsin, Perls, Sirius Red (pH = 10.2), Congo Red, and Azan trichrome for brightfield microscopy analysis. FINDINGS: At 30 and 50 dpi, live eggs and larvae were present inside the vasa vasorum of the cecal artery, leading to eosinophil infiltrates throughout the vessel adventitia and promoting centripetal vasculitis with disruption of the elastic layers. Disease severity increased at 90 and 114 dpi, when many worms had died and the intensity of the vascular lesions was greatest, with intimal alterations, thrombus formation, iron accumulation, and atherosclerosis. CONCLUSION: In addition to abdominal angiostrongyliasis, our data suggest that this model could be very useful for autoimune vasculitis and atherosclerosis studies.

Brazilian Angiostrongylus cantonensis haplotypes, ac8 and ac9, have two different biological and morphological profiles.

Angiostrongylus cantonensis is the etiologic agent of eosinophilic meningoencephalitis in humans. Cases have been recorded in many parts of the world, including Brazil. The aim of this study was to compare the differences in the biology and morphology of two different Brazilian haplotypes of A. cantonensis: ac8 and ac9. A significantly larger number of L1 larvae eliminated in the faeces of rodents at the beginning of the patent period was observed for ac9 haplotype and compared to the total of L1 larvae eliminated, there was a significant difference between the two haplotypes. The ac9 haplotype showed a significant difference in the proportion of female and male specimens (0.6:1), but the same was not observed for ac8 (1.2:1). The morphometric analysis showed that male and female specimens isolated from ac8 haplotype were significantly larger with respect to body length, oesophagus length, spicule length (male) and distance from the anus to the rear end (female) compared to specimens from ac9. The morphological analysis by light microscopy showed little variation in the level of bifurcations at the lateral rays in the right lobe of the copulatory bursa between the two haplotypes. The biological, morphological and morphometric variations observed between the two haplotypes agree with the observed variation at the molecular level using the cytochrome oxidase subunit I marker and reinforce the possible influence of geographical isolation on the development of these haplotypes.

Biological, biochemical and histopathological features related to parasitic castration of Biomphalaria glabrata infected by Schistosoma mansoni.

Parasitic castration in the snail-trematode relationship can be understood as any change in the reproductive function of the snail that is due to interference by the developing larvae inside the snail that leads to the reduction or complete disruption of egg-laying activity. This study was designed to observe the parasitic castration of Biomphalaria glabrata infected with Schistosoma mansoni during both the pre-patent and patent periods. The effect of infection on snail fecundity and fertility, growth rate and survival was studied during the 62 days following miracidia exposure. An integrated approach was employed that used biochemical and histological tools over the same period. To study the effect of infection on reproduction, we individually exposed 30 snails to 5 miracidia each and tracked their fertility and fecundity. For our histopathological studies, 50 snails were exposed to 20 miracidia each, and for our histochemical studies, 50 snails were exposed to 5 miracidia each. An equal number of uninfected snails were used as a control for each group. The B. glabrata exposed to the BH strain of S. mansoni showed 50% positivity for cercarial shedding. Both the experimental and control groups showed 100% survival. The pre-patent period lasted until 39 days after exposure to miracidia. Exposed snails that showed cercarial shedding exhibited higher growth rates than either exposed snails that did not demonstrate cercarial shedding or uninfected controls. Exposed snails without cercarial shedding and uninfected controls showed no differences in the reproductive parameters evaluated during the patent period; snails experiencing cercarial shedding showed a reduction in fecundity and fertility. These snails began to lay eggs only after the 50th day post miracidia exposure. The haemolymph glucose levels showed an oscillating pattern that decreased during periods of greater mobilisation of energy by the larvae and was accompanied by a depletion of glycogen in the cephalopodal mass and digestive gland. Histopathological examination at 55 days showed that the ovotestis was highly atrophied. There was almost complete disappearance of germ cells, and the supporting stroma formed a nearly empty net. At day 45, the infected digestive gland showed a high cylindrical epithelium with little preserved cytoplasm. The contents of the secretory granules of the albumen gland of infected animals stained with Alcian blue (AB), pH 1.0, indicating the presence of sulphated carbohydrates. Thus, parasitic castration in the B. glabrata-S. mansoni model may be regulated directly and indirectly by the developmental stage of the trematode and the biochemical and histopathological alterations during the patent period of infection.

A Structural Analysis of Host-Parasite Interactions in Achatina fulica (Giant African Snail) Infected with Angiostrongylus cantonensis.

Angiostrongylus cantonensis is a nematode parasite that resides in the pulmonary arteries of rodents, serving as its definitive hosts. The life cycle involves several species of non-marine gastropods as intermediate hosts, and the African giant snail Achatina fulica is considered one of the most important around the world. Experimental data concerning A. cantonensis infection in the African giant snail remains notably limited. This helminth causes eosinophilic meningitis or meningoencephalitis in humans, representing an emergent zoonosis in Brazil. Understanding the host-parasite relationship through the application of new tools is crucial, given the complex interaction between zoonosis and the intricate mechanisms involving wild/human hosts, parasite adaptation, and dispersion. The objective of this study was to employ SEM as a novel methodology to understand the structural organization of the host tissue, particularly the granuloma formation. This sheds light on the complex balance between A. fulica and A. cantonensis. Nine three-month-old snails were randomly selected and exposed for 24 h to a concentration of 2000 L1/dose of A. cantonensis. A necropsy was performed 37 days after the infection, and the samples were examined using light and scanning electron microscopy (SEM). The histopathological results revealed third-stage larvae of A. cantonensis associated with granulomas distributed throughout the head-foot mass, mantle, and kidney. Scanning electron microscopy of the histological section surface showed that the granuloma is surrounded by a cluster of spherical particles, which are distributed in the region bordering the larvae. This reveal details of the nematode structure, demonstrating how this methodology can enhance our understanding of the role of granulomas in molluscan tissue. The structural characteristics of granuloma formation in A. fulica suggest it as an excellent invertebrate host for A. cantonensis. This relationship appears to provide protection to the parasite against the host's immune defense system while isolating the snail's tissue from potential exposure to nematode antigens.

Proteolytic activity in the adult and larval stages of the human roundworm parasite Angiostrongylus costaricensis.

Angiostrongylus costaricensis is a nematode that causes abdominal angiostrongyliasis, a widespread human parasitism in Latin America. This study aimed to characterize the protease profiles of different developmental stages of this helminth. First-stage larvae (L1) were obtained from the faeces of infected Sigmodon hispidus rodents and third-stage larvae (L3) were collected from mollusks Biomphalaria glabrata previously infected with L1. Adult worms were recovered from rodent mesenteric arteries. Protein extraction was performed after repeated freeze-thaw cycles followed by maceration of the nematodes in 40 mM Tris base. Proteolysis of gelatin was observed by zymography and found only in the larval stages. In L3, the gelatinolytic activity was effectively inhibited by orthophenanthroline, indicating the involvement of metalloproteases. The mechanistic class of the gelatinases from L1 could not be precisely determined using traditional class-specific inhibitors. Adult worm extracts were able to hydrolyze haemoglobin in solution, although no activity was observed by zymography. This haemoglobinolytic activity was ascribed to aspartic proteases following its effective inhibition by pepstatin, which also inhibited the haemoglobinolytic activity of L1 and L3 extracts. The characterization of protease expression throughout the A. costaricensis life cycle may reveal key factors influencing the process of parasitic infection and thus foster our understanding of the disease pathogenesis.

Manganese (II) removal from aqueous solutions by Cladosporium halotolerans and Hypocrea jecorina.

Manganese (Mn) is toxic at higher concentrations requiring its removal before returning the wastewater to the environment. This article reported the Mn removal of two fungi strains isolated from mine wastewater. ITS rRNA region sequencing identified the fungi strains as Cladosporium halotolerans and Hypocrea jecorina. Mn2+ removal assays were performed in Sabouraud broth with 50 mg L-1 Mn2+ supplemented and bioleaching assays using MnO2 instead of MnSO4 at the same conditions. C. halotolerans removed 96 % of 50 mg L-1 Mn2+ at two weeks without MnO2 bioleaching with 649.9 mg of biomass and H. jecorina removed about 50 % of Mn2+ in 21 days from initial 50 mg of Mn2+ L-1 with 316.8 mg of biomass. Extracellular laccases were present in C. halotolerans agar regardless of the Mn addition. Mn adsorbed was detected on C. halotolerans hyphae. Mn oxidation was positive to H. jecorina by reaction of its medium with Leucoberbelin blue.

A New Species of Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae) from Myotis riparius Handley, 1960 (Chiroptera: Vespertilionidae) in the Atlantic Forest of Brazil, with a Checklist of Eimeria spp. Reported from Bats.

INTRODUCTION: A new coccidian species of the genus Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae), is reported from the bat host Myotis riparius Handley from Ilha Grande, a large island off the coast of the State of Rio de Janeiro, in southeastern Brazil. METHODS: Bats were captured in 13 mist nets (10 × 3 m), which were set within the experimental plots, and through active searches of the daytime roosts of Molossus molossus Pallas found in Vila Dois Rios. Containment was made in bags for the collection of feces and identification of coccidia. A survey was conducted on the coccidia species described so far (Table 2). RESULTS: The oöcysts of Eimeria riparii n. sp. are ellipsoidal to cylindroidal with an extremely thin, bi-layered wall, slightly rough. Two polar granules are present, micropyle and oöcyst residuum are both absent. The sporocysts are ellipsoidal, the sporocyst residuum is formed by sparse, rounded granules of varying sizes; the Stieda body is trapezoidal and a sub-Stieda body is absent. Sporozoites are banana shaped. With the new species described here, a total of 40 Eimeria spp. have been described infecting bat hosts, belonging to 30 species of 18 genera and 5 families. CONCLUSION: The subsequent increase in the known diversity of bats has been derived from the ongoing expansion of research in a number of different areas of taxonomy and ecology although the number of studies of the associated coccidian parasites of the family Eimeriidae has increased more slowly.

Epigenetic and parasitological parameters are modulated in EBi3-/- mice infected with Schistosoma mansoni.

Schistosoma mansoni adaptive success is related to regulation of replication, transcription and translation inside and outside the intermediate and definitive host. We hypothesize that S. mansoni alters its epigenetic state in response to the mammalian host immune system, reprogramming gene expression and altering the number of eggs. In response, a change in the DNA methylation profile of hepatocytes could occurs, modulating the extent of hepatic granuloma. To investigate this hypothesis, we used the EBi3-/- murine (Mus musculus) model of S. mansoni infection and evaluated changes in new and maintenance DNA methylation profiles in the liver after 55 days of infection. We evaluated expression of epigenetic genes and genes linked to histone deubiquitination in male and female S. mansoni worms. Comparing TET expression with DNMT expression indicated that DNA demethylation exceeds methylation in knockout infected and uninfected mice and in wild-type infected and uninfected mice. S. mansoni infection provokes activation of demethylation in EBi3-/-I mice (knockout infected). EBi3-/-C (knockout uninfected) mice present intrinsically higher DNA methylation than WTC (control uninfected) mice. EBi3-/-I mice show decreased hepatic damage considering volume and reduced number of granulomas compared to WTI mice; the absence of IL27 and IL35 pathways decreases the Th1 response resulting in minor liver damage. S. mansoni males and females recovered from EBi3-/-I mice have reduced expression of a deubiquitinating enzyme gene, orthologs of which target histones and affect chromatin state. SmMBD and SmHDAC1 expression levels are downregulated in male and female parasites recovered from EBi3-/-, leading to epigenetic gene downregulation in S. mansoni. Changes to the immunological background thus induce epigenetic changes in hepatic tissues and alterations in S. mansoni gene expression, which attenuate liver symptoms in the acute phase of schistosomiasis.

Hepatic damage associated with dengue-2 virus replication in liver cells of BALB/c mice.

One difficulty in studying dengue virus (DENV) is the lack of an experimental model that reproduces the human disease. In a previous work, we have shown that BALB/c mice intraperitoneally inoculated with a DENV-2 isolate presented viremia and mild focal areas of liver injuries. In this study, mice were inoculated by the intravenous route and presented extensive damage areas in the liver tissue, which were evaluated by histopathological and ultrastructural analysis. Hepatic injury was noted mainly around the central vein and portal tracts. Damages consist of hepatocyte injury, including steatosis, swelling and necrosis. Further, erythrophagocytosis, intercellular edema and vascular damages were evident, including hemorrhage, which is characteristic of the dengue-induced hepatitis in human liver. Hepatic lesions were already noted 2 days post infection (p.i.), although effects were more extensive after the seventh day p.i. An increase in alanine aminotransferase and aspartate aminotransferase serum levels was detected 7 and 14 days p.i., respectively, and had correlation to hepatic lesions. Alterations caused by the DENV infection were self-limiting, with a remarkable reduction of all liver damages 49 days p.i. Virus antigens were detected in hepatocytes, Kupffer cells and vascular endothelium, suggesting virus replication in these cells. In situ hybridization, using a probe that anneals in the virus negative RNA strand, showed positive reaction in hepatocytes and vascular endothelium cells of infected mice, thus confirming virus replication in such cells. In general, results revealed that this mouse model reproduces some histopathological effects observed in humans and supports previous findings indicating virus replication in the hepatic tissue.

Activity profiling of peptidases in Angiostrongylus costaricensis first-stage larvae and adult worms.

BACKGROUND: Angiostrongylus costaricensis is a relatively uncharacterized nematode that causes abdominal angiostrongyliasis in Latin America, a human parasitic disease. Currently, no effective pharmacological treatment for angiostrongyliasis exists. Peptidases are known to be druggable targets for a variety of diseases and are essential for several biological processes in parasites. Therefore, this study aimed to systematically characterize the peptidase activity of A. costaricensis in different developmental stages of this parasitic nematode. METHODOLOGY/PRINCIPAL FINDINGS: A library of diverse tetradecapeptides was incubated with cellular lysates from adult worms and from first-stage larvae (L1) and cleaved peptide products were identified by mass spectrometry. Lysates were also treated with class specific peptidase inhibitors to determine which enzyme class was responsible for the proteolytic activity. Peptidase activity from the four major mechanistic classes (aspartic, metallo, serine and cysteine) were detected in adult worm lysate, whereas aspartic, metallo and serine-peptidases were found in the larval lysates. In addition, the substrate specificity profile was found to vary at different pH values. CONCLUSIONS/SIGNIFICANCE: The proteolytic activities in adult worm and L1 lysates were characterized using a highly diversified library of peptide substrates and the activity was validated using a selection of fluorescent substrates. Taken together, peptidase signatures for different developmental stages of this parasite has improved our understanding of the disease pathogenesis and may be useful as potential drug targets or vaccine candidates.

Morphological effects on helminth parasites caused by herbicide under experimental conditions.

Helminth parasites have been studied as potential accumulators for different pollutants. Echinostoma paraensei is a foodborne trematode whose vertebrate host, the rodent Nectomys squamipes, is naturally exposed to environmental pesticides. However, little information exists regarding the pesticide's effects on helminths. This study investigated the morphological effects on the trematode, E. paraensei, after experimental Roundup® herbicide exposure, in concentrations below those recommended for agricultural use. After two hours of exposure, scanning electron microscopy (SEM) showed changes to the tegument, such as furrowing, shrinkage, peeling, spines loss on the peristomic collar, and histopathological evidence of altered cells in the cecum and acinus vitelline glands with vacuoles and structural changes to the muscular layers. Glycidic content was decreased, primarily in the connective tissue. As E. paraensei is an intestinal parasite of the semi-aquatic wild rodent, N. squamipes, it is predisposed to pesticide exposure resulting from agricultural practices. Therefore, we emphasize the need to evaluate its impact on helminth parasites, due to their pivotal role in regulating host populations.