Search

Flatworms are known for their remarkable regenerative ability, one which depends on totipotent cells known as germinative cells in cestodes. Depletion of germinative cells with hydroxyurea (HU) affects the regeneration of the parasite. Here, we studied the reduction and recovery of germinative cells in T. crassiceps cysticerci after HU treatment (25 mM and 40 mM of HU for 6 days) through in vitro assays. Viability and morphological changes were evaluated. The recovery of cysticerci's mobility and morphology was evaluated at 3 and 6 days, after 6 days of treatment. The number of proliferative cells was evaluated using EdU. Our results show morphological changes in the size, shape, and number of evaginated cysticerci at the 40 mM dose. The mobility of cysticerci was lower after 6 days of HU treatment at both concentrations. On days 3 and 6 of recovery after 25 mM of HU treatment, a partial recovery of the proliferative cells was observed. Proteomic and Gene Ontology analyses identified modifications in protein groups related to DNA binding, DNA damage, glycolytic enzymes, cytoskeleton, skeletal muscle, and RNA binding.

The small ubiquitin-like modifier (SUMO) plays important roles, with the SUMOylation pathway as one of its core components. In the present work, a single SUMO gene was initially identified from Taenia pisiformis and designated as TpSUMO. Bioinformatic analysis showed that the TpSUMO gene contained a 309 bp open reading frame (ORF), encoding 102 amino acids, and had a predicted molecular weight of ∼12 kDa. The amino acid sequence of TpSUMO was deduced and it shared 44.00% identity with human SUMO2 (HsSUMO2) and exhibited more than 97.78% identity with SUMOs from Taenia and Echinococcus. TpSUMO possessed a putative non-consensus site (FK 11 MG) within its N-terminus and a typical di-glycine (GG) motif at the C-terminus. Basic local alignment search tool (BLAST) analysis showed that only a single SUMO-related ortholog was present in each set of known genome data for fourteen tapeworm species. The precursor His-TpSUMO-FL, mature His-TpSUMO-GG and mutant His-TpSUMO-GG K11R proteins (∼18 kDa) were expressed in Escherichia coli Rosseta (DE3), and rabbit polyclonal anti-TpSUMO was generated with a high titer of 1.28 × 10 5 . In vitro SUMOylation assay results showed that TpSUMO multimer formation in the His-TpSUMO-GG reaction could be catalyzed by the human SAE1/SAE2 and UBC9 conjugation system, but K11R mutation disrupted TpSUMO chain synthesis. Quantitative real-time PCR (qRT-PCR) further revealed that TpSUMO was ubiquitously expressed in different stages of T. pisiformis and in higher levels during an early development phase (day 14) of adult worms. Immunofluorescence localization showed that TpSUMO was detected in the bladder wall of cysticerci, in the testis in immature segment, and within eggs in the gravid proglottids. These findings indicated that TpSUMO is a new member of the SUMO protein family and may play a vital role in regulation of functions within proteins involved in worm growth and development., (Copyright © 2022. Published by Elsevier Inc.)

The expression patterns of some cytokines were compared by RT-qPCR between lambs with and without Taenia hydatigena larvae vesicular concentrate (ThLVC) administration and subsequent infection with Haemonchus contortus. Lambs that received ThLVC prior to infection with H. contortus showed lower (p < 0.03) cumulative FEC (AUC = 18450 ± 3384) than infected lambs who did not receive ThLVC (AUC = 31081 ± 3277). Lambs infected with H. contortus, in general, overexpressed Th1 and Th2 cytokines in abomasal mucosa and abomasal lymph nodes, which seems to indicate a generalized and nonpolarized activation of the immune response by H. contortus. The main immunomodulatory effects of ThLVC were observed in the abomasal fundic region. The lambs that were given ThLVC prior to infection strongly overexpressed most of the studied cytokines representing the Th1 (IFNγ and IL2) and Th2 profiles (IL4, IL5, IL6 and IL10), proinflammatory cytokines (SOD1 and PRDX6) and IgE receptor; in contrast, lambs that were infected but did not receive ThLVC only moderately overexpressed IFNγ, IL4 and IL6. The absence of the significant overexpression of cytokines in lambs that only received ThLVC suggests that this derived from T. hydatigena does not have a stimulating effect per se; however, the presence of H. contortus did produce the highest expression (p < 0.01) cytokine profile among lambs that received ThLVC prior to infection compared to those who did not receive it, so its effect seems to be immunomodulatory and not only immunostimulatory., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Cysticercosis caused by the metacestode larval stage of Taenia hydatigena formerly referred to as Cysticercus tenuicollis is a disease of veterinary importance that constitutes a significant threat to livestock production worldwide, especially in endemic regions due to condemnation of visceral organs and mortality rate of infected young animals. While the genetic diversity among parasites is found to be potentially useful in many areas of research including molecular diagnostics, epidemiology and control, that of T. hydatigena across the globe remains poorly understood. In this study, analysis of the mitochondrial DNA (mtDNA) of adult worms and larval stages of T. hydatigena isolated from dogs, sheep and a wild boar in China showed that the population structure consists of two major haplogroups with very high nucleotide substitutions involving synonymous and non-synonymous changes. Compared with other cestodes such as Echinococcus spp., the genetic variation observed between the haplogroups is sufficient for the assignment of major haplotype or genotype division as both groups showed a total of 166 point-mutation differences between the 12 mitochondrial protein-coding gene sequences. Preliminary analysis of a nuclear protein-coding gene (pepck) did not reveal any peculiar changes between both groups which suggests that these variants may only differ in their mitochondrial makeup.

Background: Taenia pisiformis is one of the most common intestinal parasites in canines, and leads to serious economic losses in the rabbit breeding industry. Exosome-like vesicles from parasites play crucial roles in host-parasite interactions by transferring cargo from parasites to host cells and by modulating host immunological response through inducing production of host-derived cytokines. Nevertheless, the mechanism by which exosome-like vesicles from T. pisiformis cysticercus regulate the macrophage immune response remains unknown., Methods: Using ultracentrifugation, we isolated exosome-like vesicles from excretory/secretory products (ESP) of T. pisiformis cysticercus. The morphology and size of purified vesicles were confirmed by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). The components of proteins and miRNAs within these vesicles were identified by proteomic analysis and high-throughput small RNA sequencing. The biological function of targets of exosomal miRNAs was predicted by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Moreover, the expression of Th1- and Th2-type immune response associated cytokines in RAW264.7 macrophages were evaluated by qPCR and ELISA. We found that exosome-like vesicles were typical cup-shaped vesicles with diameters from 30 to 150 nm. A total of 87 proteins were identified by proteomic analysis, including proteins prominently associated with exosome-like vesicles biogenesis and vesicle trafficking. 41 known miRNAs and 18 novel miRNAs were identified in the exosome-like vesicles. Eleven selected miRNAs, including 7 known miRNAs (miR-71-5p, miR-10a-5p, miR-let-7-5p, miR-745-3p, miR-219-5p, miR-124-3p and miR-4989-3p) and 4 novel miRNAs (novel-mir-3, novel-mir-7, novel-mir-8 and novel-mir-11) were validated to exist in metacestiodes and exosome-like vesicles of T. pisiformis cysticercus by qPCR. The functions of most targets of exosomal miRNAs were mainly associated with signal transduction and the immune system. Additionally, T. pisiformis cysticercus-derived vesicles induced the production of IL-4, IL-6, IL-10, IL-13 and Arg-1, but downregulated the expression of IL-12, IFN-γ and iNOS in RAW264.7 macrophages., Conclusions: We demonstrated that proteins and miRNAs enclosed within exosome-like vesicles from T. pisiformis cysticercus have immunomodulatory functions. Furthermore, exosome-like vesicles were shown to induce the macrophage Th2-type immune response in vitro. Our study suggests that exosome-like vesicles play an important role in the interaction between cysticerci and their hosts.

Taenia crassiceps is an experimental model used for cysticercosis studies and has suffered metabolic analyzes regarding the effect of anthelminthic drugs. The metabolic analyses are useful tools to determine the drugs mode of action and the parasite`s survival mechanisms. The energetic pathways are good candidates for this kind of approach as they are essential for the parasite`s survival and adaptation to the environment. In this review we discuss the anthelminthic drugs mode of action and its metabolic impact on Taenia crassiceps cysticerci., Competing Interests: Declaration of Competing Interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The benzimidazole derivative, 6-chloro-5-(2,3-dichlorophenoxy)-2-(trifluoromethyl)-1H-benzimidazole (RCB15), has a similar mode of action and efficacy as albendazole, a commonly used anthelminthic drugs. The aim of this study was to evaluate its influence on the tricarboxylic acid cycle in Taenia crassiceps cysticerci. The parasites were cultured in supplemented RPMI medium containing albendazole sulfoxide (ABZSO) or RCB15, for 24 h. Then, frozen in liquid nitrogen for organic metabolites extraction. Samples were analyzed by high performance liquid chromatography and organic acids of the tricarboxylic acid cycle were detected. It was possible to observe changes in the concentrations of all acids involved in this metabolic pathway, with the exception of α-ketoglutarate, which was not detected in the control group neither in most of the treated groups. It indicates that the parasite presented a partial inhibition of the tricarboxylic acid cycle. The significant increase in the concentration of citrate, oxaloacetate and succinate in the RCB15 treated groups may indicate an activation of the fumarate reductase pathway, leading to metabolic distress. Therefore RCB15 may be considered an alternative for the treatment of tissue parasitic diseases, since it induced changes in the main metabolic pathway of the parasite., Competing Interests: Declaration of Competing Interest None, (Copyright © 2019 Elsevier B.V. All rights reserved.)

Nitazoxanide (NTZ) is a broad-spectrum drug used in intestinal infections, but still poorly explored in the treatment of parasitic tissular infections. This study aimed to evaluate the in vitro responses of the energetic metabolism of T. crassiceps cysticerci induced by NTZ. The organic acids of the tricarboxylic acid cycle, products derived from fatty acids oxidation and protein catabolism were analyzed. These acids were quantified after 24 h of in vitro exposure to different NTZ concentrations. A positive control group was performed with albendazole sulfoxide (ABZSO). The significant alterations in citrate, fumarate and malate concentrations showed the NTZ influence in the tricarboxylic acid (TCA) cycle. The non-detection of acetate confirmed that the main mode of action of NTZ is effective against T. crassiceps cysticerci. The statistical differences in fumarate, urea and beta-hydroxybutyrate concentrations showed the NTZ effect on protein catabolism and fatty acid oxidation. Therefore, the main energetic pathways such as the TCA cycle, protein catabolism and fatty acids oxidation were altered after in vitro NTZ exposure. In conclusion, NTZ induced a significant metabolic stress in the parasite indicating that it may be used as an alternative therapeutic choice for cysticercosis treatment. The use of metabolic approaches to establish comparisons between anti parasitic drugs mode of actions is proposed., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Inflammation is currently considered a hallmark of cancer and plays a decisive role in different stages of tumorigenesis, including initiation, promotion, progression, metastasis and resistance to antitumor therapies. Colorectal cancer is a disease widely associated with local chronic inflammation. Additionally, extrinsic factors such as infection may beneficially or detrimentally alter cancer progression. Several reports have noted the ability of various parasitic infections to modulate cancer development, favoring tumor progression in many cases and inhibiting tumorigenesis in others. The aim of our study was to determine the effects of excreted/secreted products of the helminth Taenia crassiceps (TcES) as a treatment in a murine model of colitis-associated colon cancer (CAC). Here, we found that after inducing CAC, treatment with TcES was able to reduce inflammatory cytokines such as IL-1β, TNF-α, IL-33 and IL-17 and significantly attenuate colon tumorigenesis. This effect was associated with the inhibition of signal transducer and activator of transcription 3 and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) phosphorylation. Furthermore, we determined that TcES interfered with LPS-induced NF-κB p65 activation in human colonic epithelial cell lines in a Raf-1 proto-oncogene-dependent manner. Moreover, in three-dimensional cultures, TcES promoted reorganization of the actin cytoskeleton, altering cell morphology and forming colonospheres, features associated with a low grade of aggressiveness. Our study demonstrates a remarkable effect of helminth-derived molecules on suppressing ongoing colorectal cancer by downregulating proinflammatory and protumorigenic signaling pathways., (© 2019 UICC.)

Leucine aminopeptidase of Taenia pisiformis (TpLAP) belonging to the M17 peptidase family has been implicated as a stage-differentially expressed protein in the adult stage of T. pisiformis. In order to further dissect the biological functions of TpLAP in the growth and development of adult worms, TpLAP-interacting partners were investigated. In this study, a yeast two-hybrid (Y2H) cDNA library from adult T. pisiformis was constructed. Using pGBKT7-TpLAP as bait, proteins interacting with TpLAP were screened by Y2H system and positive preys were sequenced and analyzed using the Basic Local Alignment Search Tool (BLAST). Our results showed that six genuine TpLAP-interacting proteins, including LAP, dynein light chain (DLC), SUMO-conjugating enzyme (UBC9), histone-lysine n-methyltransferase, trans-acting transcriptional, and one unknown protein, were identified via Y2H assay. Furthermore, the interaction between TpLAP and UBC9 of T. pisiformis (TpUBC9), an important protein involved in SUMOylation pathway, was further validated by one-to-one Y2H assay, co-immunoprecipitation, and confocal analysis. These findings provide a deeper understanding of the biological functions of TpLAP and offer the first clue that TpLAP may act as a novel SUMOylated substrate, suggesting that the SUMO modification pathway plays an important role in regulation of adult worm growth and development.

An experimental Taenia crassiceps mouse model was used to assess the role of Taenia solium metacestode factor (Fac) in human neurocysticercosis. Intraperitoneal infection with T. crassiceps metacestodes or subcutaneous inoculation with a T. crassiceps metacestode factor (Fac) produced significant impairment of performance (learning) in the Barnes maze and induced bilateral hippocampal sclerosis in mice. Several staining techniques revealed important cell dispersion, extensive apoptosis and cell loss in the dentate gyrus, hilus and CA1-CA3 regions of both hippocampi, as well as intense deterioration of the adjacent cortex. An outstanding disruption of its histoarchitecture in the surrounding tissue of all these regions and apoptosis of the endothelial cells were also observed.

Coenurosis is a serious parasitic disease of herbivorous animals caused by the metacestode of Taenia multiceps (Coenurus cerebralis). Accordingly, a significant amount of research is currently dedicated to the development of appropriate antigens for use in rapid and accurate coenurosis diagnosis kits. In the present study, antigen B (AgB) and thioredoxin peroxidase (TPx) from T. multiceps were cloned and expressed using a prokaryotic system, molecular characterization of Tm-AgB was determined by bioinformatical analyses. The serological diagnostic potentials of rTm-AgB and rTm-TPx were evaluated by indirect ELISA and compared with those of previously reported rTm-AnxB2, rTm-HSP70, and rTm-GST. The results showed that Tm-AgB is a specific lipoprotein of cestodes with good thermal stability. The ELISA assay showed that rTm-AgB exhibited a sensitivity of 95.8% and a specificity of 87.5%, indicating its strong potential for serological diagnosis of T. multiceps., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Neurocysticercosis is the most frequent helminthiasis of the central nervous system and is caused by the presence of Taenia solium cysticerci. Nitazoxanide (NTZ) is an antifolate containing the pyrrolopyrimidine-based nucleus that exerts its antiprotozoal activity due to interference with the pyruvate:ferredoxin oxidoreductase (PFOR) enzyme which is essential to anaerobic energy metabolism. The aim of this work was to determine the effect of NTZ on the energetic metabolism of Taenia crassiceps cysticerci intracranially inoculated BALB /c mice. The infected animals were treated with a single oral dose of NTZ 30 days after the inoculation. Analysis of the organic acids was performed through high performance liquid chromatography. Glucose was detected only in the treated groups, alongside with a significant decrease in lactate, pyruvate and oxaloacetate concentrations which indicate an increase in gluconeogenesis. The non-detection of alpha-ketoglutarate indicated the use of the fumarate reductase pathway in all groups. It was possible to confirm the drugs mode of action due to the non-detection of acetate in the treated groups. There was an increase in the fatty acids oxidation. Therefore it was possible to observe that NTZ induces gluconeogenesis as well as the increase of alternative energetic pathways such as fatty acids oxidation in T. crassiceps cysticerci., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Taenia multiceps is an adult worm affiliated to Taeniidae family, Platyhelminthes phylum. The larvae of the parasite (Coenurus cerebralis) parasitic in the brain and spinal cord in domestic and wild ruminants or humans can led to a fatal central nervous system (CNS) disease. The aims of the present study were to define the transcriptome profiles of the larvae of T. multiceps by RNA-Seq approach, and to generate large functional gene datasets that could be used to predict the key molecular pathways linked to this cestode. Our results generated a total of 39,094,890 clean reads that were assembled from the sequence data in 90,833 contigs. Briefly, 70,253 unigenes with a mean length of 1492bp were formed. Based on a sequence similarity search against the databases (NR, Swissport, GO, COG, KEGG) using BLASTX with an E-value cutoff of 10 -5 , 40,465 of unigenes were identified as coding sequences (CDS) and 3261 were scanned by ESTScan. The present study carried out the transcriptome of the larval stage of T. multiceps, which provides a solid foundation for further studies in molecular biology and biochemistry as well as identification of candidate genes used in diagnosis and vaccine development., (Copyright © 2017. Published by Elsevier Ltd.)

Taenia crassiceps cysticerci are used as experimental model to study the host-parasite relationship and treatment of cysticercosis. One of the described mode of actions of nitazoxanide (NTZ) is to block the pyruvate ferredoxine oxidoreductase (PFOR) enzyme which is an essential enzyme to the parasite metabolism. The aim of this study was to determine the in vivo influence of one dosage of NTZ on the energetic metabolism of T. crassiceps cysticerci. Thirty days after the intraperitoneal inoculation of T. crassiceps cysticerci, BALB/c mice were orally treated with 7.5 mg/kg of NTZ. The control group was treated with physiologic solution (NaCl 0.9%). After 24 h, the animals were euthanized and the cysticerci were removed, washed, and processed for biochemical analysis. The organic acids detection occurred through high-performance liquid chromatographic and spectrophotometric analysis. While there was no difference in the glucose dosages, it was possible to observe a significant increase in the lactate concentrations and a decrease in the pyruvate concentrations of the NTZ-treated groups when compared to the control group. Also, there was a decrease in the urea and alpha-ketoglutarate concentrations. This probably occurred due to the impairment of the parasite's PFOR and nitroreductases leading an impairment of the mitochondrial aerobic pathways. In conclusion, the in vivo NTZ treatment leads to an increase in the lactic fermentation and to a decrease in the protein catabolism in T. crassiceps cysticerci.

Neglected tropical diseases caused by helminth infections currently affect millions of people worldwide. Among them, there are three tapeworm species of outstanding importance: Echinococcus granulosus, E. multilocularis, and Taenia solium, which are responsible for cystic echinococcosis, alveolar echinococcosis, and cysticercosis, respectively. Despite several attempts, there is still a need for an effective and low-cost serological diagnostic test that can be used in endemic countries. In the present work, we described an innovative bioinformatic workflow for a rational prediction of putative peptide candidates for one-step serological diagnosis of any of these infections. First, we predicted the theoretical secretome shared by the three tapeworms starting from their full reported proteomes. Then, through immunoinformatics, we identified proteins within the shared secretome displaying high antigenicity scores and bearing T cell epitopes able to bind most human MHC-II alleles. Secondly, in such proteins, we identified linear B cell epitopes without post-translational modifications, and mapped them on 3D modelled structures to visualize their antibody accessibilities. As a result, we finally suggested two antigenic peptides shared between the secretomes of the three parasite species, which could be further tested for their immunodiagnostic potential., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Taenia multiceps is a widespread zoonotic tapeworm parasite which infects cloven-hoofed animals around the world. Animal infection with Coenurus cerebralis, the coenurus larvae of T. multiceps (Tm), is often fatal, which is a major cause of economic losses in stockbreeding. This study amplified the glutathione S-transferase (GST) gene from the total RNA of C. cerebralis. The resulting protein, Tm-GST, consisted of 201 amino acids, and had a predicted molecular mass of 23.1kDa. Its amino acid sequence shares 77.61% similarity with Echinococcus granulosus GST. Recombinant Tm-GST (rTm-GST) was expressed in Escherichia coli. The protein reacted with serum from goats infected with T. multiceps. Immunofluorescence signals indicated that Tm-GST was largely localized in the parenchymatous area of adult T. multiceps; in addition, it was also apparent in the coenurus. An enzyme-linked immunosorbent assay based on rTm-GST showed specificity of 92.8% (13/14) and sensitivity of 90% (18/20) in detecting anti-GST antibodies in serum from naturally infected animals. This study suggests that Tm-GST has the potential to be used as a diagnostic antigen for Coenurosis., (Copyright © 2017. Published by Elsevier B.V.)

Background: Codon usage bias (CUB) is an important evolutionary feature in genomes that has been widely observed in many organisms. However, the synonymous codon usage pattern in the genome of T. multiceps remains to be clarified. In this study, we analyzed the codon usage of T. multiceps based on the transcriptome data to reveal the constraint factors and to gain an improved understanding of the mechanisms that shape synonymous CUB., Results: Analysis of a total of 8,620 annotated mRNA sequences from T. multiceps indicated only a weak codon bias, with mean GC and GC3 content values of 49.29% and 51.43%, respectively. Our analysis indicated that nucleotide composition, mutational pressure, natural selection, gene expression level, amino acids with grand average of hydropathicity (GRAVY) and aromaticity (Aromo) and the effective selection of amino-acids all contributed to the codon usage in T. multiceps. Among these factors, natural selection was implicated as the major factor affecting the codon usage variation in T. multiceps. The codon usage of ribosome genes was affected mainly by mutations, while the essential genes were affected mainly by selection. In addition, 21codons were identified as "optimal codons". Overall, the optimal codons were GC-rich (GC:AU, 41:22), and ended with G or C (except CGU). Furthermore, different degrees of variation in codon usage were found between T. multiceps and Escherichia coli, yeast, Homo sapiens. However, little difference was found between T. multiceps and Taenia pisiformis., Conclusions: In this study, the codon usage pattern of T. multiceps was analyzed systematically and factors affected CUB were also identified. This is the first study of codon biology in T. multiceps. Understanding the codon usage pattern in T. multiceps can be helpful for the discovery of new genes, molecular genetic engineering and evolutionary studies.

The use of oxygen as the final electron acceptor in aerobic organisms results in an improvement in the energy metabolism. However, as a byproduct of the aerobic metabolism, reactive oxygen species are produced, leaving to the potential risk of an oxidative stress. To contend with such harmful compounds, living organisms have evolved antioxidant strategies. In this sense, the thiol-dependent antioxidant defense systems play a central role. In all cases, cysteine constitutes the major building block on which such systems are constructed, being present in redox substrates such as glutathione, thioredoxin, and trypanothione, as well as at the catalytic site of a variety of reductases and peroxidases. In some cases, the related selenocysteine was incorporated at selected proteins. In invertebrate parasites, antioxidant systems have evolved in a diversity of both substrates and enzymes, representing a potential area in the design of anti-parasite strategies. The present review focus on the organization of the thiol-based antioxidant systems in invertebrate parasites. Differences between these taxa and its final mammal host is stressed. An understanding of the antioxidant defense mechanisms in this kind of parasites, as well as their interactions with the specific host is crucial in the design of drugs targeting these organisms.

Nitazoxanide (NTZ) is a broad-spectrum anti-parasitic drug used against a wide variety of protozoans and helminthes. Albendazole, its active metabolite albendazole sulfoxide (ABZSO), is one of the drugs of choice to treat both intestinal and tissue helminth and protozoan infections. However little is known regarding their impact on the metabolism of parasites. The aim of this study was to compare the in vitro effect of NTZ and ABZSO in the glycolysis of Taenia crassiceps cysticerci. The cysticerci were treated with 1.2; 0.6; 0.3 or 0.15 μg/mL of NTZ or ABZSO. Chromatographic and spectrophotometric analyses were performed in the culture medium and in the cysticerci extract. Regarding the glucose concentrations was possible to observe two responses: impair of the uptake and gluconeogenesis. The pyruvate concentrations were increased in the ABZSO treated group. Lactate concentrations were increased in the culture medium of NTZ treated groups. Therefore it was possible to infer that the metabolic acidosis was greater in the group treated with NTZ than in the ABZSO treated group indicating that this is one of the modes of action used by this drug to induce the parasite death., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The aim of this work was to develop nanosuspensions of praziquantel (PZQ) and to evaluate their influence on the energetic metabolism of cysticerci inoculated in BALB/c mice. We analyzed metabolic alterations of glycolytic pathways and the tricarboxylic acid cycle in the parasite. The nanosuspensions were prepared by precipitation and polyvinyl alcohol (PVA), poloxamer 188 (P188) and poloxamer 407 (P407) were used as stabilizers. Nanosuspension prepared with PVA had a particle size of 100nm, while P188- and P407-based nanosuspensions had particle sizes of 74nm and 285nm, respectively. The zeta potential was -8.1, -8.6, and -13.2 for the formulations stabilized with PVA, P188 and P407, respectively. Treatments of T. crassiceps cysticerci-infected mice resulted in an increase in glycolysis organic acids, and enhanced the partial reversion of the tricarboxylic acid cycle, the urea cycle and the production of ketonic bodies in the parasites when compared to the groups treated with conventional PZQ. These data suggest that PZQ nanosuspensions greatly modified the energetic metabolism of cysticerci in vivo. Moreover, the remarkable metabolic alterations produced by the stabilizers indicate that further studies on nanoformulations are required to find potentially suitable nanomedicines., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Biochemical studies of benzimidazole derivatives are important to determine their mode of action and activity against parasites. The lack of antihelminthic alternatives to treat parasitic infections and albendazole resistance cases make the search for new antiparasitary drugs of utmost importance. The 6-chloro-5-(1-naphthyloxy)-2-(trifluoromethyl)-1H-benzimidazole (RCB20) is a benzimidazole derivative with promising effect. This study evaluated the effect of different concentrations of RCB20 in the alternative energetic pathway of in vitro Taenia crassiceps cysticerci. The parasites were in vitro exposed to 6.5 and 13 µM of RCB20 and albendazole sulfoxide (ABZSO). The quantification of acetate, acetoacetate, β-hydroxybutyrate, fumarate and propionate was performed by high-performance liquid chromatography. The quantification of urea, creatinine and total proteins was performed by spectrophotometry. The increase in β-hydroxybutyrate reflects the enhancement of the fatty acid oxidation in the treated groups. Volatile fatty acids secretion, acetate and propionate, was increased in the treated groups. The secretion mechanisms of the treated parasites were impaired due to organic acids increased concentrations in the cysticerci. It is possible to conclude that the metabolic effect on alternative energetic pathways is slightly increased in the parasites treated with RCB20 than the ones treated with ABZSO.

This study was undertaken to determine whether a parasite substance produces structural pathology in the mouse spleen. A low-molecular-weight Taenia crassiceps metacestode factor (MF) isolated from the peritoneal fluid of female mice infected with T. crassiceps metacestodes induced pathological and immunological changes in mouse spleen cells in vivo. Electron microscopy and confocal microscopy revealed severe changes in the spleen histoarchitecture of T. crassiceps-infected and MF-treated mice. Apoptotic degenerated spleen cells were observed in the white and red pulps and were more conspicuous in the white pulp of the spleen from the T. crassiceps-infected mice than in that of the MF-treated mice. Flow cytometry analysis revealed that the numbers of spleen CD4+T cells were significantly lower in both experimental groups than in control mice. The ex vivo expression of transforming growth factor (TGF)-β and factor Foxp3 were significantly higher in splenocytes of the experimental mice than the basal expression observed in the control cells. These findings may have potential applications for a better understanding of the host-parasite relationship in human neurocysticercosis.

Thioredoxin (Trx) is an oxidoreductase central to redox homeostasis in cells and is involved in the regulation of protein activity through thiol/disulfide exchanges. Based on these facts, our goal was to purify and characterize cytosolic thioredoxin from Taenia crassiceps cysticerci, as well as to study its behavior as a substrate of thioredoxin-glutathione reductase (TGR). The enzyme was purified >133-fold with a total yield of 9.7%. A molecular mass of 11.7kDa and a pI of 4.84 were measured. Native electrophoresis was used to identify the oxidized and reduced forms of the monomer as well as the presence of a homodimer. In addition to the catalytic site cysteines, cysticerci thioredoxin contains Cys28 and Cys65 residues conserved in previously sequenced cestode thioredoxins. The following kinetic parameters were obtained for the substrate of TGR: a Km of 3.1μM, a kcat of 10s(-1) and a catalytic efficiency of 3.2×10(6)M(-1)s(-1). The negative patch around the α3-helix of Trx is involved in the interaction with TGR and suggests variable specificity and catalytic efficiency of the reductase toward thioredoxins of different origins., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

It is well understood that helminth infections modulate the immune responses of their hosts but the mechanisms involved in this modulation are not fully known. Macrophages and dendritic cells appear to be consistently affected during this type of infection and are common target cells for helminth-derived molecules. In this report, we show that macrophages obtained from chronically Taenia crassiceps-infected mice displayed an impaired response to recombinant murine IFN-γ, but not to recombinant murine IL-4, as measured based on the phosphorylation of STAT1 and STAT6, respectively. These macrophages expressed high levels of SOCS3. However, the inhibition of phosphatase activity by orthovanadate restored the IFN-γ response of these macrophages by increasing STAT1 phosphorylation without affecting SOCS3 expression. Therefore, we aimed to identify the phosphatases associated with IFN-γ signaling inhibition and found that macrophages from T. crassiceps-infected mice displayed enhanced SHP-1 expression. Interestingly, the exposure of naïve macrophages to T. crassiceps excreted/secreted products similarly interfered with IFN-γ-induced STAT1 phosphorylation. Moreover, macrophages exposed to T. crassiceps excreted/secreted products expressed high levels of SOCS3 as well as SHP-1. Strikingly, human peripheral blood mononuclear cells that were exposed to T. crassiceps excreted/secreted products in vitro also displayed impaired STAT1 phosphorylation in response to IFN-γ; again, phosphatase inhibition abrogated the T. crassiceps excreted/secreted product-altered IFN-γ signaling. These data demonstrate a new mechanism by which helminth infection and the products derived during this infection target intracellular pathways to block the response to inflammatory cytokines such as IFN-γ in both murine and human cells., (Copyright © 2014 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.)

The Taenia crassiceps ORF strain is used to generate a murine model of cysticercosis, which is used for diagnosis, evaluation of drugs, and vaccination. This particular strain only exists as cysticerci, is easily maintained under in vivo and in vitro conditions, and offers an excellent model for studying the cytoskeletons of cestodes. In this study, several experimental approaches were used to determine the tissue expression of its cytoskeletal proteins. The techniques used were microscopy (video, confocal, and transmission electron), one-dimensional (1D) and two-dimensional (2D) electrophoresis, immunochemistry, and mass spectrometry. The tissue expression of actin, tubulin, and paramyosin was assessed using microscopy, and their protein isoforms were determined with 1D and 2D electrophoresis and immunochemistry. Nineteen spots were excised from a proteomic gel and identified by liquid chromatography-tandem mass spectrometry and immunochemistry. The proteins identified were classic cytoskeletal proteins, metabolic enzymes, and proteins with diverse biological functions, but mainly involved in detoxification activities. Research suggests that most noncytoskeletal proteins interact with actin or tubulin, and the results of the present study suggest that the proteins identified may be involved in supporting the dynamics and plasticity of the cytoskeleton of T. crassiceps cysticerci. These results contribute to our knowledge of the cellular biology and physiology of cestodes.

Neurocysticercosis (NCC) is the most common helminthic infection and neglected disease of the central nervous system. It is the leading cause of acquired epilepsy and seizures worldwide. Therefore, to study this important neglected disease, it is important to use experimental models. There is no report in the literature on how the parasite's metabolism reacts to antihelminthic treatment when it is still within the central nervous system of the host. Therefore, the aim of this study was to investigate the energetic metabolism of cysticerci experimentally inoculated in the encephala of BALB/c mice after treatment with low dosages (not sufficient to kill the parasite) of albendazole (ABDZ) and praziquantel (PZQ). BALB/c mice were intracranially inoculated with Taenia crassiceps cysticerci and, after 30 days, received treatment with low dosages of ABDZ and PZQ. After 24 h of treatment, the mice were euthanized, and the cysticerci were removed and analyzed through high-performance liquid chromatography (HPLC) to quantify the organic acids related to the energetic metabolism of the parasite. The partial reverse of the TCA cycle was enhanced by the ABDZ and PZQ treatments both with the higher dosage, as the organic acids of this pathway were significantly increased when compared to the control group and to the other dosages. In conclusion, it was possible to detect the increase of this pathway in the parasites that were exposed to low dosages of ABDZ and PZQ, as it is a mechanism that would amplify the energy production in a hostile environment.

Cysticerci and tapeworms from Taenia crassiceps WFU, ORF and Taenia solium synthesize sex-steroid hormones in vitro. Corticosteroids increase the 17β-estradiol synthesis by T. crassiceps cysticerci. T. crassiceps WFU cysticerci synthesize corticosteroids, mainly 11-deoxycorticosterone (DOC). The aim of this work was to investigate whether classical steroidogenic inhibitors modify the capacity of T. crassiceps WFU cysticerci to synthesize corticosteroids and sex steroid hormones. For this purpose, T. crassiceps WFU cysticerci were obtained from the abdominal cavity of mice, pre-cultured for 24h in DMEM+antibiotics/antimycotics and cultured in the presence of tritiated progesterone ((3)H-P4), androstendione ((3)H-A4), or dehydroepiandrosterone ((3)H-DHEA) plus different doses of the corresponding inhibitors, for different periods. Blanks with the culture media adding the tritiated precursors were simultaneously incubated. At the end of the incubation period, parasites were separated and media extracted with ether. The resulting steroids were separated by thin layer chromatography (TLC). Data were expressed as percent transformation of the tritiated precursors. Results showed that after 2h of exposure of the cysticerci to 100 μM formestane, the (3)H-17β-estradiol synthesis from tritiated androstenedione was significantly inhibited. The incubation of cysticerci in the presence of (3)H-DHEA and danazol (100 nM) resulted in (3)H-androstenediol accumulation and a significant reduction of the 17β-estradiol synthesis. The cysticerci (3)H-DOC synthesis was significantly inhibited when the parasites were cultured in the presence of different ketoconazole dosis. The drug treatments did not affect parasite's viability. The results of this study showed that corticosteroid and sex steroid synthesis in T. crassiceps WFU cysticerci can be modified by steroidogenic enzyme inhibitors. As was shown previously by our laboratory and others, parasite survival and development depends on sex steroids, therefore the inhibition of their synthesis is a good starting point exploited in situations where the inhibition of steroidogenesis could help to control the infection for the development of new treatments, or replacement of the usual therapy in resistant parasite infections. We raise the possibility that these drug actions may be beneficially., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Rabbit cysticercosis, caused by the larval stage of Taenia pisiformis, is a serious parasitic disease of rabbits. It was reported that some cysteine peptidases have potential roles in the pathogenesis of various parasitic infections. To investigate the biochemical characteristics and roles in the pathogenesis/host-invasion of cysteine peptidases, a cDNA sequence encoding for a cathepsin L-like cysteine protease (TpCP) was cloned and identified from the T. pisiformis metacestodes. This sequence was 1220 bp in its length, which included a 1017 bp open reading frame encoding a 339 amino acid peptide. Multiple sequence alignments revealed a 28.9-88.5% similarity with cathepsin L-like cysteine proteases from other helminth parasites and mammals. The recombinant TpCP expressed in Escherichia coli did not show the proteolytic activity by zymography gel assay. However, the TpCP expressed in Pichia pastoris had typical biochemical activities that could hydrolyze rabbit immunoglobulin G, bovine serum albumin and fibronectin. Substrate studies indicated pronounced cleavage of Z-Phe-Arg-AMC. This activity was sensitive to cysteine protease inhibitor E-64 and immunohistochemistry results also indicated that TpCP was distributed as an intense positive reaction in the bladder wall. Our results gave us insights into future studies of TpCP's roles in the infection., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Taenia multiceps (Cestoda: Taeniidae), a worldwide cestode parasite, is emerging as an important helminthic zoonosis due to serious or fatal central nervous system disease commonly known as coenurosis in domestic and wild ruminants including humans. Herein, a fatty acid-binding protein (FABP) gene was identified from transcriptomic data in T. multiceps. This gene, which contains a complete coding sequence, was amplified by reverse-transcriptase polymerase chain reaction. The corresponding protein, which was named TmFABP, had a molecular weight of 14 kDa, and subsequently was recombinantly expressed in Escherichia coli. The fusion protein was purified on Ni-NTA beads (Bio-Rad). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analyses showed that the purified recombinant protein caused immunogenicity. Immunohistochemical studies showed that TmFABP was expressed at the tegumental level in the protoscolices and in the cells between the body wall and parenchyma layer of the cestode. In sections from gravid proglottids, intense staining was detected in the uterus and eggs. Based on this, TmFABP could be switched on during differentiation of germinative layers to protoscoleces and from metacestodes to adult worms. Taken together, our results already reported for T. multiceps suggest the possibility of TmFABP developing a vaccine to control and prevent coenurosis.

Macrophages are critically involved in the interaction between T. crassiceps and the murine host immune system. Also, a strong gender-associated susceptibility to murine cysticercosis has been reported. Here, we examined the sex-associated expression of molecules MHC-II, CD80, CD86, PD-L1, and PD-L2 on peritoneal F4/80(hi) macrophages of BALB/c mice infected with Taenia crassiceps. Peritoneal macrophages from both sexes of mice were exposed to T. crassiceps total extract (TcEx). BALB/c Females mice recruit higher number of macrophages to the peritoneum. Macrophages from infected animals show increased expression of PDL2 and CD80 that was dependent from the sex of the host. These findings suggest that macrophage recruitment at early time points during T. crassiceps infection is a possible mechanism that underlies the differential sex-associated susceptibility displayed by the mouse gender.

We have shown previously that cultured Taenia crassiceps Wake Forest University (WFU) and Taenia solium cysticerci, as well as the adult worms, synthesize sex steroid hormones from [3H]steroid precursors and that androgens and oestrogens influence the in vitro development of the parasites. Glucocorticoids (GCs) are used to control the inflammation caused by T. solium cysticerci in the brain. These steroids stimulate oestrogen synthesis in several tissues. Since there is no information on the effect of GC on the endocrine function of cysticerci, we investigated the effect of natural and synthetic GCs on the synthesis of oestrogens in cultured T. crassiceps WFU cysticerci. The cysticerci were obtained from the peritoneal cavity of infected female BALB/c mice; the cysts were washed extensively and pre-cultured in Dulbecco's Modified Eagle's Medium (DMEM) plus antibiotics for 5 days. The parasites were further cultured with different doses of corticosterone, dexamethasone or the vehicle for 5 days. [3H]Dehydroepiandrosterone (3H-DHEA) was added to the media and the cysticerci were further incubated for 6 or 24 h. Media were then removed and the steroids ether-extracted. Aliquots of the media were seeded on silica gel plates and developed in solvent systems. Parasites incubated in the presence of 3H-DHEA synthesized [3H]androstenediol, [3H]testosterone and [3H]17β-oestradiol ([3H]17β-E2). The addition of 100 nm or higher corticosterone doses to the media increased [3H]17β-E2 synthesis fourfold after 24 h. Dexamethasone also increased [3H]17β-E2 synthesis. The experiments presented here show for the first time that corticosterone and the synthetic GC dexamethasone modulate the synthesis of oestrogens by cysticerci.

Taenia solium and Taenia crassiceps WFU cysticerci and tapeworms have the ability to synthesize sex steroid hormones and have a functional 3β-hydroxisteroid dehydrogenase. Corticosteroids (CS) like corticosterone and dexamethasone have been shown to stimulate in vitro estrogen production by Taenia crassiceps WFU cysticerci. The aim of this work was to study the ability of T. crassiceps WFU cysticerci to synthesize corticosteroids, and the effect of the inhibitor metyrapone on the CS synthesis. For this purpose T. crassiceps WFU cysticerci were obtained from the abdominal cavity of mice, thoroughly washed and pre-incubated in multiwells for 24 h in DMEM plus antibiotics/antimycotics. The tritiated CS precursor progesterone ((3)H-P4) was added to the culture media and parasites cultured for different periods. Blanks containing the culture media plus the (3)H-P4 were simultaneously incubated. Blanks and parasite culture media were ether extracted and analyzed by thin layer chromatography (TLC) in two different solvent systems. Corticosterone production was measured in the culture media by RIA. In some experiments metyrapone (0.1-0.5 mM) was added for 24, 48 or 72 h. Results showed that cysticerci mainly synthesized tritiated 11-deoxy corticosterone (DOC) and small amounts of corticosterone that was also detected by RIA. Small amounts of (3)H-11-deoxy cortisol were also found. Corticosteroid synthesis was time dependent. The addition of metyrapone significantly inhibited tritiated DOC, deoxycortisol and corticosterone synthesis. These results show for the first time that parasites have the capacity to synthesize CS that is modulated by metyrapone. Data suggest that DOC is the main corticosteroid in the parasites., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Echinococcosis, coenurosis and cysticercosis are debilitating diseases which prevail in China. Immunological diagnosis of metacestodosis is important in disease control. The 8-kDa glycoproteins from taeniid cestodes have successfully been used for diagnosis of human cysticercosis in immunological assays. The aim of the present study was to investigate genetic variations and phylogenetic relationships of the 8-kDa proteins for evaluating the possibility of utilizing these proteins as diagnostic antigens for other metacestode infections., Methods: The genes and complementary DNAs (cDNAs) encoding the 8-kDa proteins from Echinococcus (E.) granulosus, Taenia (T.) multiceps and T. hydatigena were amplified using PCR method. Their amplicons were cloned into the vector pMD18 and the positive clones were sequenced. Sequence data were analyzed with the SeqMan program, and sequence homology searches were performed using the BLAST program. Alignments were conducted using the ClustalX program, and the phylogenetic analyses were performed with the Protein Sequences Program and the Puzzle Program using the Neighbor-joining method., Results: Fifteen, 18 and 22 different genomic DNA sequences were identified as members of the 8-kDa protein gene family from E. granulosus, T. multiceps and T. hydatigena, respectively. Eight, four and six different cDNA clones respectively from E. granulosus, T. multiceps and T. hydatigena were characterized. Analysis of these sequences revealed 54 unique 8-kDa protein sequences. Phylogenetic trees demonstrated that the taeniid 8-kDa proteins are clustered into eight clades at least: Ts18, Ts14, TsRS1, TsRS2, T8kDa-1, T8kDa-2, T8kDa-3 and T8kDa-4., Conclusion: We found that the gene family encoding for the taeniid 8-kDa antigens is comprised of many members with high diversity, which will provide molecular evidence for cross-reaction or specific reaction among metacestode infections and may contribute to the development of promising immunological methods for diagnosis of metacestodosis.

The aim of this work was to investigate the lipid content of Taenia hydatigena eggs and to evaluate the role of lipids in the maintenance of embryo viability. The total lipid content of the egg was 4.5% (w/w). Five classes of neutral lipids were identified: esterified cholesterol, free cholesterol, triacylglycerols, diacylglycerols and free fatty acids. Our results suggest that triacylglycerols play a key role in the maintenance of embryo viability. In addition, we found that T. hydatigena eggs remain metabolically active by mobilisation of stored triacylglycerols. This study contributes to the understanding the survival strategies of a member of the Taeniidae family in the environment outside the host.

The tegumental membrane of Taenia crassiceps cysticerci contains an ATP-diphosphohydrolase (EC 3.6.1.5) which hydrolyzes purine and pyrimidine nucleoside 5'-di- and 5'-triphosphates at an optimum pH of 8.5. It is Mg(2+)-dependent and insensitive to classical ATPase and phosphatase inhibitors. In solubilized tegumental membrane the Km values varied from 220 to 480 microM and the V(max) from 370 to 748 nmol of Pi release/mg/min for nucleoside triphosphates (ATP, GTP, CTP, UTP, and TTP); for nucleoside diphosphates (ADP, GDP, CDP, and UDP) the Km values were from 260 to 450 microM and the V(max) from 628 to 1134 nmol of Pi release/mg/min. An antibody specific to CD39 shows cross-reactivity with T. crassiceps ATP-diphosphohydrolase, revealing a single protein of approximately 80 kDa. Incubation of ATP-diphosphohydrolase with FSBA inhibited ATPase and ADPase activities by 85-90%. Immunoblot analyses, the competition plot, similar inhibition by free nucleotides, the lack of effect of Mg(2+) at high concentrations, and the inactivation by FSBA of ATPase and ADPase activity strongly suggest that a single enzyme catalyzes the hydrolysis of all these nucleotides. The mechanism of ATP hydrolysis shows that ATP-diphosphohydrolase releases ADP during the catalytic cycle. Incubation of intact cysticerci with FSBA caused 70-80% inhibition of ATPase and ADPase activities, indicating that the active site of the ATP-diphosphohydrolase is oriented to the external surface of the tegument of T. crassiceps. The importance of this enzyme in the parasite-host relationship is discussed.

Taenia crassiceps cysticerci is used as an experimental model to cysticercosis studies; however there are subcutaneous cases of cysticercosis caused by these cysticerci. It remains unclear in the literature the energetic and fatty acid metabolism in cestodes. Its metabolic study may provide knowledge of pathways that may serve as potential anti-helminthic drugs sites of action. In this work we studied the citric acid cycle organic acids and the fatty acid oxidation in cysticerci removed from mice with 21 and 42 days of infection in two different evolutive stages: growing and final. The organic acids were extracted using perchloric acid and analyzed by HPLC methodology. We found significant statistically differences in oxalate, malate, lactate, and beta-hydroxybutirate concentrations between cysticerci. These results indicate the aerobic metabolism in vivo in spite of the low oxygen concentration of its habitat, and also indicate the presence of fatty acid oxidation as an alternative energetic source.

Although the presence of intact host proteins in the cyst fluid of cyclophyllidean metacestodes has been well documented, the underlying reason for protein uptake is poorly understood. To investigate this discrepancy, both the cyst fluid (CF) and excreted/secreted (E/S) proteins were collected in vitro from Taenia crassiceps metacestodes 16 wk postinfection in Balb/cJ female mice. The CF and E/S were subsequently immunoblotted using rabbit anti-mouse whole serum antibodies as a probe. The results show that whole host proteins were not only internalized by metacestodes but also secreted as well. The predominant secreted host protein was 66 kDa and was confirmed to be mouse serum albumin. The amount of secreted albumin decreased daily, whereas the concentration of albumin in the cyst fluid remained consistent. This suggests that the secretion of albumin is a coordinated function rather than a random event. It is probable that albumin cycling may be an evolved mechanism providing multiple benefits for the larvae, including osmoregulation and protection from innate immune responses.

Common helminth infections promote Th2-skewed immune responses in their hosts. We have studied the role of intact carbohydrate structures on Taenia crassiceps compounds in the induction of biased type 2 and anti-inflammatory immune responses on peptide-stimulated T cells by using DO11.10 transgenic (OVA Tg) mice. While OVA Tg mice co-injected with OVA peptide (323-339) (OVA(323-339)) plus intact Taenia soluble antigens (iTSA) displayed significantly higher titers of OVA-specific IgG1 and total IgE, low amounts of these antibodies were detectable in sera from OVA Tg mice co-injected with OVA(323-339) plus periodate-carbohydrate altered TSA (paTSA). Spleen cells from OVA Tg mice failed to efficiently produce OVA-specific IFN-gamma but displayed higher IL-4, IL-5 and IL-10 production when they received OVA(323-339) plus iTSA, compared with OVA Tg mice similarly co-injected with OVA(323-339) plus paTSA. Moreover, after in vivo stimulation with OVA(323-339) plus iTSA, spleen cells did show elevated mRNA transcripts for Arginase 1, Ym1, IL-4, IL-10, TGF-beta, and Mannose Receptor (MR) genes, all them associated with Th2-type and anti-inflammatory responses. Similar results were obtained using TLR4 mutant mice. Together these findings suggest that carbohydrate components in TSA are involved in modulating immune responses to bystander antigens and that do not signal via TLR4.

Previous in vitro experiments showed that both, Taenia crassiceps and Taenia solium cysticerci have the ability to metabolize exogenous androstenedione to testosterone. Here we evaluate on the capacity of both cysticerci to synthesize several sex steroid hormones, using different hormonal precursors. Experiments using thin layer chromatography (TLC) showed that both cysticerci were able to produce (3)H-hydroxyprogesterone, (3)H-androstenedione and (3)H-testosterone when (3)H-progesterone was used as the precursor. They also synthesized (3)H-androstenediol and (3)H-testosterone when (3)H-dehydroepiandrosterone was the precursor. In addition, both cysticerci interconverted (3)H-estradiol and (3)H-estrone. These results, strongly suggest the presence and activity of the Delta4 and Delta5 steroid pathway enzymes, 3beta-hydroxysteroid dehydrogenase/Delta(5-4) isomerase-like enzyme (3beta-HSD), that converts androstenediol into testosterone; and the 17beta-hydroxysteroid dehydrogenase that interconverts estradiol and estrone, in both types of cysticerci.

Complex glycans derived from lipid, nucleic acid and protein free extracts of Taenia crassiceps metacestode larvae were found to have adjuvant effect against Leishmania mexicana antigens in BALB/c mice experimentally infected with L. mexicana. A single intraperitoneal or subcutaneous injection of Taenia glycans altered the Th-1/Th-2 balance in experimentally infected mice as determined by Western blot analysis of IgG 1 and IgG 2a antibodies to L. mexicana antigens. Leishmania antigens which were immunogenic in Taenia glycan vaccinated mice were different from those of non-vaccinated mice. Vaccination induced leishmania antigen specific IFN-gamma expression in vitro culture by spleen cells from Taenia glycan vaccinated-leishmania infected mice and not from mock vaccinated-leishmania infected BALB/c mice. We conclude that T. crassiceps glycans have immunoadjuvant effects against leishmania and may be developed as adjuvants in anti-leishmania vaccines.

Experimental taeniid strobilae from Taenia solium and T. crassiceps (WFU strain) were incubated for 0-72 h in 0, 5 or 20 mM glucose solutions and further exposed for 15 min to the gap junction fluorochrome Lucifer Yellow. Frozen sections were obtained from each worm and observed under an epifluorescent microscope. Worm sections from strobilae incubated with glucose, revealed intense fluorescence in the base of the tegumentary surface, suggesting that this tissue behaves as a gap junction complex. Fluorescence intensity differences between control worms not exposed to glucose and worms incubated with glucose, were highly significant. The results demonstrate that under in vitro conditions, glucose is taken up along the whole strobilar tegument in both taeniid species, suggesting, that although taeniids attached to the duodenum probably take up most of their nutrients directly from the mucosal wall, the capacity for absorbing glucose along the tegumentary surface is always active and may increase the survival capacity of these intestinal worms by promoting glucose absorption at other points in the intestinal lumen.

Concentrations of lead, determined by electrothermal atomic absorption spectrometry, were compared between the cestodes Hymenolepis diminuta and Taenia taeniaeformis and its host rat (Rattus norvegicus). Rats were sampled at 2 sites, which differed in respect to lead pollution as quantified from road dust, adjacent to the city of Cairo, Egypt. Comparing lead levels among host tissues and the parasites the significantly highest accumulation was found in H. diminuta, followed by rat kidney and larvae of T. taeniaeformis. Calculation of bioconcentration factors showed that H. diminuta contained 36-, 29-, 6- and 6-fold higher lead levels than intestinal wall, liver, kidney and larvae of T. taeniaeformis, at the more polluted site. At the less contaminated site lead bioconcentration factors for H. diminuta were found to be 87, 87 and 11 referred to intestine, liver and kidney of the host. Due to a high variability of the lead concentrations in H. diminuta it was not possible to indicate differences in metal pollution between both sampling sites. This variability may be influenced by different age structures of cestode infrapopulations. It is likely that younger worms contain lower metal levels than older worms due to a shorter exposure period. Thus, it is necessary to standardize the sampling of worms which should be used for indication purposes. Due to a lack of adequate sentinel species in terrestrial habitats more studies are required to validate and standardize the use of helminths as accumulation bioindicators in order to obtain mean values with low standard deviations. The host-parasite system rat-H. diminuta appears to be a useful and promising bioindication system at least for lead in urban ecosystems as rats as well as the tapeworm are globally distributed and easily accessible.

This article focuses on the initiation pathway of mucin-type O-glycosylation in helminth parasites. The presence of the GalNAc-O-Ser/Thr structure, also known as Tn antigen, a truncated determinant related to aberrant glycosylation in mammal cells, and the activity of the UDP-GalNAc:polypeptide N-acetyl-galactosaminyltransferase (ppGaNTase), the enzyme responsible for its synthesis, were studied in species from major taxonomic groups. Tn reactivity was determined in extracts from Taenia hydatigena, Mesocestoides corti, Fasciola hepatica, Nippostrongylus brasiliensis, and Toxocara canis using the monoclonal antibody 83D4. The Tn determinant was revealed in all preparations, and multiple patterns of Tn-bearing glycoproteins were observed by immunoblotting. Additionally, the first evidence that helminth parasites express ppGaNTase activity was obtained. This enzyme was studied in extracts from Echinococcus granulosus, F. hepatica, and T. canis by measuring the incorporation of UDP-(3H)GalNAc to both deglycosylated ovine syalomucin (dOSM) and synthetic peptide sequences derived from tandem repeats of human mucins. Whereas significant levels of ppGaNTase activity were detected in all the extracts when dOSM was used as a multisite acceptor, it was only observed in F. hepatica and E. granulosus extracts when mucin-derived peptides were used, suggesting that T. canis ppGaNTase enzyme(s) may represent a member of the gene family with a more restricted specificity for worm O-glycosylation motifs. The widespread expression of Tn antigen, capable of evoking both humoral and cellular immunity, strongly suggests that simple mucin-type O-glycosylation does not constitute an aberrant phenomenon in helminth parasites.

Cysticercosis is caused by the metacestode form of Taenia solium-Cysticercus cellulosae and it causes great economic losses and threatens the people's health. There are some problems on how to control cysticercosis, in order to resolve the key problem that the native antigen to diagnose and prevent cysticercosis is very limited and is not satisfied, Pichia pastoris Expression System was used to express recombinant P2 protein. The interested P2 gene was got by digesting the pGEM - P2 vector using restriction endonuclease, then it was inserted into the secretory pPIC9K Pichia pastoris expression vector and transformed into E. coli. Positive recombinant plasmids were selected sequenced and named pPIC9K-P2 and it was linearized by Sal I and Bgl II, then the linear DNA transfored into Pichia pastoris GS115 by electroporation. The recombinant expression vector pPIC9K - P2 integrated into GS115 via homologous recombination between the transforming DNA and regions of homology within the genome. The transformants were screened for multicopy recombinants using G418 and were distinguished for Mut phenotypes by MD and MM. Two different phenotypes were generated-HIS+ MUT+ (Methanol utilization plus) and HIS+ MUT(S) (Methanol utilization slow). PCR analysis of the multicopy recombinants indicated that the P2 gene was integrated within the genome of pichia Pastoris. The multicopy recombinants were named GS115/pPIC9K - P2HIS+ MUT+ and GS115/pPIC9K-P2HIS+ MUT(S), both HIS+ MUT+ and HIS+ MUT(S) were induced with methanol. The results of SDS-PAGE and Western blot demonstrated that the culture supernatant of the induced Pichia pastoris contained P2 protein which was accumulated up to 33 % of total proteins in the culture supernant and its molecular weight is 12.6kD. The results of the clinical study indicated that the expression P2 protein could be used to diagnose human cysticercosis and swine cysticercosis as diagnosis antigen.

Infection of rat liver by Taenia taeniformis metacestodes produced an increase in total CYP450 content and induced activity of the CYP1A1, CYP2B1 and COH isoforms. Variations in activity and p450 total content were found with increasing time of infection. During increased activity of p450 isoforms, rats were challenged with carcinogens metabolized by the mentioned isozymes and an increased amount of genotoxic damage was found when benzo[a] pyrene, cyclophosphamide and aflatoxin B(1) were used. No change was seen in CYP2E1 activity. These results support previous findings regarding an increased susceptibility to genotoxic damage of infected organisms.

The influence of hepatic larval Taenia taeniaeformis infection on gastric acid secretory activity and gastric mucosal integrity was investigated. After 12 weeks of infection with 2,000 T. taeniaeformis eggs, the gastric pH values of control and infected rats were 4.1+/-0.6 (mean +/- SD) and 8.4+/-0.2, respectively. There was no difference in the basal acid secretion between control (1.7+/-0.7 micro Eq.H(+)/15 min) and infected (1.9+/-0.3) rats. However, infected rats failed to respond to histamine stimulation, the maximum acid output level being 2.8+/-0.4 in the infected rats, compared to 12.9+/-3.3 in control rats. Larval T. taeniaeformis infection resulted in the suppression of gastric acid secretion leading to hypergastrinemia.

Cysticercosis caused by the metacestode of the tapeworm Taenia solium causes economic losses in pork meat production, as well as being a human health hazard in some parts of the world. In order to determine if the glucose transporters TGTPI and TGTP2 are recognized by antibodies in the sera from cysticercotic humans and pigs, western blot assays were carried out using membrane fractions of insect cells expressing the two T. solium glucose transporters. Results demonstrated a complete lack of recognition of both TGTPs. These results are unexpected, because at least one transporter is present on the apical surface of the cysticercus tegument.

Cestode worms, commonly also known as 'flat' worms or tapeworms, are an important class of endoparasitic organisms. In order to complete their life cycle, they infect intermediate and definitive hosts in succession, through oral ingestion of eggs or larvae, respectively. Serious disease in humans or other mammalian hosts is mostly caused by the larval stages. Echinococcus spp. and Taenia spp. have been extensively investigated in the laboratory due to the fact that they represent important veterinary medical challenges and also cause grave diseases in humans. In contrast, Hymenolepis spp. and Mesocestoides spp. infections are relatively rare in humans, but these parasites have been extensively studied because their life cycle stages can be easily cultured in vitro, and can also be conveniently maintained in laboratory animal hosts. Thus they are more easily experimentally accessible, and represent important models for investigating the various aspects of cestode biology. This review will focus on in vitro and in vivo models which have been developed for studies on the host-parasite relationship during infection with Echinococcus, Taenia, Hymenolepis, Mesocestoides and Spirometra, and will cover the use of these models to investigate the morphology and ultrastructure of respective genera, the immunological relationship with the host and the development of vaccination approaches, as well as applications of these models for studies on parasite metabolism, physiology and gene expression. In addition, the use of these models in the development of chemotherapeutic measures against cestode infections is reviewed.

A metacestode factor (MF) isolated from live metacestodes of Taenia solium suppresses humoral and cellular responses, and inhibits the inflammatory reaction around metacestodes implanted subcutaneously in mice. When this MF is digested with RNase (dMF), it loses the suppressive capacity, but acquires T-cell stimulant ability. By filtering MF through a Bio-gel P6 column, two components were separated. The first (F1) was suppressive. while the second (F2) stimulated T cells to proliferate. In these experiments, F2 or dMF was used with mouse spleen cells in stimulation assays in vitro. Spleen cells from mice treated with F2 or dMF were also stimulated with concanavalin A (Con-A) ex vivo. Flow cytometry analyses were performed to estimate cell proliferation, intracellular cytokine production. and restoration of CD4 cells. Spleen lymphocytes from mice previously treated with F2 or dMF and then stimulated with Con-A ex vivo exhibited a significant increase in cell proliferation and gamma interferon production by CD4+ (P<0.05) and CD8+ cells. These effects were concentration-dependent and inversely correlated with the amount of dMF or F2. Similar results were observed in normal mouse spleen T cells incubated with F2 or dMF and Con-A in vitro. Finally, dMF induced a significant restoration of CD4-cells in mice depleted of these cells.