Identification of enzymes that have helminth-specific active sites and are required for Rhodoquinone-dependent metabolism as targets for new anthelmintics.

Soil transmitted helminths (STHs) are major human pathogens that infect over a billion people. Resistance to current anthelmintics is rising and new drugs are needed. Here we combine multiple approaches to find druggable targets in the anaerobic metabolic pathways STHs need to survive in their mammalian host. These require rhodoquinone (RQ), an electron carrier used by STHs and not their hosts. We identified 25 genes predicted to act in RQ-dependent metabolism including sensing hypoxia and RQ synthesis and found 9 are required. Since all 9 have mammalian orthologues, we used comparative genomics and structural modeling to identify those with active sites that differ between host and parasite. Together, we found 4 genes that are required for RQ-dependent metabolism and have different active sites. Finding these high confidence targets can open up in silico screens to identify species selective inhibitors of these enzymes as new anthelmintics.

Serine Protease from Nereis virens Inhibits H1299 Lung Cancer Cell Proliferation via the PI3K/AKT/mTOR Pathway.

This study explores the in vitro anti-proliferative mechanism between Nereis Active Protease (NAP) and human lung cancer H1299 cells. Colony formation and migration of cells were significantly lowered, following NAP treatment. Flow cytometry results suggested that NAP-induced growth inhibition of H1299 cells is linked to apoptosis, and that NAP can arrest the cells at the G0/G1 phase. The ERK/MAPK and PI3K/AKT/mTOR pathways were selected for their RNA transcripts, and their roles in the anti-proliferative mechanism of NAP were studied using Western blots. Our results suggested that NAP led to the downregulation of p-ERK (Thr 202/Tyr 204), p-AKT (Ser 473), p-PI3K (p85), and p-mTOR (Ser 2448), suggesting that NAP-induced H1299 cell apoptosis occurs via the PI3K/AKT/mTOR pathway. Furthermore, specific inhibitors LY294002 and PD98059 were used to inhibit these two pathways. The effect of NAP on the downregulation of p-ERK and p-AKT was enhanced by the LY294002 (a PI3K inhibitor), while the inhibitor PD98059 had no obvious effect. Overall, the results suggested that NAP exhibits antiproliferative activity by inducing apoptosis, through the inhibition of the PI3K/AKT/mTOR pathway.

Mercury, Lead and Cadmium Concentrations in Talpa occidentalis and in Their Digeneans of the Genus Ityogonimus.

INTRODUCTION: Many parasites living in aquatic ecosystems are useful indicators of environmental health. On the other hand, information is scarcer with respect to the use of helminth parasites of vertebrates living in terrestrial ecosystems as monitoring tools for toxic element environmental pollution. The present study evaluates the suitability of the model Talpa occidentalis/Ityogonimus spp. as a bioindicator system for mercury (Hg), lead (Pb) and cadmium (Cd) contamination in agricultural soils from Asturias (Spain). METHODS: Kidney and liver samples collected from T. occidentalis specimens (n = 36) and Ityogonimus spp. samples collected from 14 infected hosts were analyzed by ICP-MS. RESULTS: The highest mean levels of Hg and Pb were found in Ityogonimus individuals (20.9 and 12.4 µg g-1 wet weight, respectively). Considering renal and hepatic concentrations in T. occidentalis, bioaccumulation factors of Ityogonimus for Hg were 83.7 and 58.6, respectively, whereas concerning Pb bioaccumulation factors were 38.2 and 82.9, respectively. No bioaccumulation was detected in Ityogonimus in the case of Cd. CONCLUSIONS: More studies involving digenean parasites of small mammals are needed, especially when biomonitoring environmental toxic element pollution in terrestrial ecosystems. The present results support the above-mentioned model as a suitable biomonitoring system to evaluate environmental Hg and Pb contamination in terrestrial non-urban Iberian habitats. Similar models involving other species (Talpa spp./Ityogonimus spp.) might be used in a much wider geographical range.

Helminth Defense Molecules as Design Templates for Membrane Active Antibiotics.

A design template for membrane active antibiotics against microbial and tumor cells is described. The template is an amino acid sequence that combines the properties of helminth defense molecules, which are not cytolytic, with the properties of host-defense peptides, which disrupt microbial membranes. Like helminth defense molecules, the template folds into an amphipathic helix in both mammalian host and microbial phospholipid membranes. Unlike these molecules, the template exhibits antimicrobial and anticancer properties that are comparable to those of antimicrobial and anticancer antibiotics. The selective antibiotic activity of the template builds upon a functional synergy between three distinctive faces of the helix, which is in contrast to two faces of membrane-disrupting amphipathic structures. This synergy enables the template to adapt pore formation mechanisms according to the nature of the target membrane, inducing the lysis of microbial and tumor cells.

Shear-Induced ß-Crystallite Unfolding in Condensed Phase Nanodroplets Promotes Fiber Formation in a Biological Adhesive.

Natural materials provide an increasingly important role model for the development and processing of next-generation polymers. The velvet worm Euperipatoides rowelli hunts using a projectile, mechanoresponsive adhesive slime that rapidly and reversibly transitions into stiff glassy polymer fibers following shearing and drying. However, the molecular mechanism underlying this mechanoresponsive behavior is still unclear. Previous work showed the slime to be an emulsion of nanoscale charge-stabilized condensed droplets comprised primarily of large phosphorylated proteins, which under mechanical shear coalesce and self-organize into nano- and microfibrils that can be drawn into macroscopic fibers. Here, we utilize wide-angle X-ray diffraction and vibrational spectroscopy coupled with in situ shear deformation to explore the contribution of protein conformation and mechanical forces to the fiber formation process. Although previously believed to be unstructured, our findings indicate that the main phosphorylated protein component possesses a significant ß-crystalline structure in the storage phase and that shear-induced partial unfolding of the protein is a key first step in the rapid self-organization of nanodroplets into fibers. The insights gained here have relevance for sustainable production of advanced polymeric materials.

Failure of the Anti-Inflammatory Parasitic Worm Product ES-62 to Provide Protection in Mouse Models of Type I Diabetes, Multiple Sclerosis, and Inflammatory Bowel Disease.

Parasitic helminths and their isolated secreted products show promise as novel treatments for allergic and autoimmune conditions in humans. Foremost amongst the secreted products is ES-62, a glycoprotein derived from Acanthocheilonema viteae, a filarial nematode parasite of gerbils, which is anti-inflammatory by virtue of covalently-attached phosphorylcholine (PC) moieties. ES-62 has been found to protect against disease in mouse models of rheumatoid arthritis, systemic lupus erythematosus, and airway hyper-responsiveness. Furthermore, novel PC-based synthetic small molecule analogues (SMAs) of ES-62 have recently been demonstrated to show similar anti-inflammatory properties to the parent molecule. In spite of these successes, we now show that ES-62 and its SMAs are unable to provide protection in mouse models of certain autoimmune conditions where other helminth species or their secreted products can prevent disease development, namely type I diabetes, multiple sclerosis and inflammatory bowel disease. We speculate on the reasons underlying ES-62's failures in these conditions and how the negative data generated may help us to further understand ES-62's mechanism of action.

The Untapped Pharmacopeic Potential of Helminths.

The dramatic rise in immunological disorders that occurs with socioeconomic development is associated with alterations in microbial colonization and reduced exposure to helminths. Excretory-secretory (E/S) helminth products contain a mixture of proteins and low-molecular-weight molecules representing the primary interface between parasite and host. Research has shown great pharmacopeic potential for helminth-derived products in animal disease models and even in clinical trials. Although in its infancy, the translation of worm-derived products into therapeutics is highly promising. Here, we focus on important key aspects in the development of immunomodulatory drugs, also highlighting novel approaches that hold great promise for future development of innovative research strategies.

Effect of dewatering and composting on helminth eggs removal from lagooning sludge under semi-arid climate.

In this work, we assessed the drying and composting effectiveness of helminth eggs removal from sewage sludge of a lagoon wastewater treatment plant located in Chichaoua city. The composting was run after mixing sludge with green waste in different proportions: M1 (½ sludge + ½ green waste), M2 ([Formula: see text] sludge + [Formula: see text] green waste), and M3 ([Formula: see text] sludge + [Formula: see text] green waste) for 105 days. The analysis of the dewatered sewage sludge showed a load of 8-24 helminth eggs/g of fresh matter identified as Ascaris spp. eggs (5-19 eggs/g) followed by Toxocara spp. (0.2 to 2.4 eggs/g); Hookworm spp. and Capillaria spp. (0.4-1 egg/g); Trichuris spp., Taenia spp., and Shistosoma spp. (< 1 egg/g) in the untreated sludge. After 105 days of treatment by composting, we noted a total reduction of helminth eggs in the order of 97.5, 97.83, and 98.37% for mixtures M1, M2, and M3, respectively. The Ascaris spp. eggs were reduced by 98% for M1 and M3 treatments and by 97% for M2 Treatment. Toxocara spp., Hookworm spp., Trichuris spp., Capillaria spp., and Shistosoma spp. eggs were totally eliminated (100% decrease) and the Taenia spp. was absent from the first stage of composting. These results confirm the effectiveness of both dehydrating and composting processes on the removal of helminth eggs.

Helminth Products Potently Modulate Experimental Autoimmune Encephalomyelitis by Downregulating Neuroinflammation and Promoting a Suppressive Microenvironment.

A negative correlation between the geographical distribution of autoimmune diseases and helminth infections has been largely associated in the last few years with a possible role for such type of parasites in the regulation of inflammatory diseases, suggesting new pathways for drug development. However, few helminth-derived immunomodulators have been tested in experimental autoimmune encephalomyelitis (EAE), an animal model of the human disease multiple sclerosis (MS). The immunomodulatory activities of Taenia crassiceps excreted/secreted products (TcES) that may suppress EAE development were sought for. Interestingly, it was discovered that TcES was able to suppress EAE development with more potency than dexamethasone; moreover, TcES treatment was still effective even when inoculated at later stages after the onset of EAE. Importantly, the TcES treatment was able to induce a range of Th2-type cytokines, while suppressing Th1 and Th17 responses. Both the polyclonal and the antigen-specific proliferative responses of lymphocytes were also inhibited in EAE-ill mice receiving TcES in association with a potent recruitment of suppressor cell populations. Peritoneal inoculation of TcES was able to direct the normal inflammatory cell traffic to the site of injection, thus modulating CNS infiltration, which may work along with Th2 immune polarization and lymphocyte activation impairment to downregulate EAE development.

Exploration of interaction zones of ß-tubulin colchicine binding domain of helminths and binding mechanism of anthelmintics.

Numerous studies postulated the possible modes of anthelmintic activity by targeting alternate or extended regions of colchicine binding domain of helminth ß-tubulin. We present three interaction zones (zones vide -1 to -3) in the colchicine binding domain of Haemonchus contortus (a helminth) ß-tubulin homology model and developed zone-wise structure-based pharmacophore models coupled with molecular docking technique to unveil the binding hypotheses. The resulted ten structure-based hypotheses were then refined to essential three point pharmacophore features that captured recurring and crucial non-covalent receptor contacts and proposed three characteristics necessary for optimal zone-2 binding: a conserved pair of H bond acceptor (HBA to form H bond with Asn226 residue) and an aliphatic moiety of molecule separated by 3.75±0.44Å. Further, an aliphatic or a heterocyclic group distant (11.75±1.14Å) to the conserved aliphatic site formed the third feature component in the zone-2 specific anthelmintic pharmacophore model. Alternatively, an additional HBA can be substituted as a third component to establish H bonding with Asn204. We discern that selective zone-2 anthelmintics can be designed effectively by closely adapting the pharmacophore feature patterns and its geometrical constraints.

Fluorescence hyperspectral imaging technique for foreign substance detection on fresh-cut lettuce.

BACKGROUND: Non-destructive methods based on fluorescence hyperspectral imaging (HSI) techniques were developed to detect worms on fresh-cut lettuce. The optimal wavebands for detecting the worms were investigated using the one-way ANOVA and correlation analyses. RESULTS: The worm detection imaging algorithms, RSI-I(492-626)/492 , provided a prediction accuracy of 99.0%. The fluorescence HSI techniques indicated that the spectral images with a pixel size of 1 × 1 mm had the best classification accuracy for worms. CONCLUSION: The overall results demonstrate that fluorescence HSI techniques have the potential to detect worms on fresh-cut lettuce. In the future, we will focus on developing a multi-spectral imaging system to detect foreign substances such as worms, slugs and earthworms on fresh-cut lettuce. © 2017 Society of Chemical Industry.

Helminth glycomics - glycan repertoires and host-parasite interactions.

Glycoproteins and glycolipids of parasitic helminths play important roles in biology and host-parasite interaction. This review discusses recent helminth glycomics studies that have been expanding our insights into the glycan repertoire of helminths. Structural data are integrated with biological and immunological observations to highlight how glycomics advances our understanding of the critical roles that glycans and glycan motifs play in helminth infection biology. Prospects and challenges in helminth glycomics and glycobiology are discussed.

Comparison between merthiolate-iodine-formalin and Kato-Katz methods for the diagnosis of human helminth infections in resource-limited settings.

Diagnosis of intestinal parasites through examination of fresh faecal samples is hampered by its unpleasantness and the urgent need to detect all parasitic forms. In this paper, we compared the standard Kato-Katz (KK) technique with a traditional fixation method, the merthiolate-iodine-formalin (MIF) method. Two hundred and twenty-seven faecal samples from individuals living in a rural setting in Venezuela with high to moderate prevalences of Ascaris lumbricoides (Al), Trichuris trichiura (Tt) and hookworm infections were examined. The 'gold standard' used here was derived from the combination of the outcomes from both methods. KK performed better at detecting Tt, and showed higher sensitivity and negative predictive value for both Tt and Al, probably due to a higher capacity of KK to detect low parasite loads. Both methods showed an almost perfect agreement using the Kappa index. MIF provided a higher median of parasitic loads for low and total egg counts for the three helminths. Differentiating fertile from infertile eggs of Al did not affect the results; infertile eggs were present only at low and intermediate parasitic loads, but absent at high loads. KK was not able to detect high loads of any of the helminths. MIF allowed for the detection of other helminths, such as Strongyloides stercoralis, and protozoan infections, for which KK is not specific. In conclusion, MIF is a simple and inexpensive technique that performs competitively with KK in both laboratory and field work on intestinal helminths, particularly in resource-limited settings.

Schistosome-Derived Molecules as Modulating Actors of the Immune System and Promising Candidates to Treat Autoimmune and Inflammatory Diseases.

It is long known that some parasite infections are able to modulate specific pathways of host's metabolism and immune responses. This modulation is not only important in order to understand the host-pathogen interactions and to develop treatments against the parasites themselves but also important in the development of treatments against autoimmune and inflammatory diseases. Throughout the life cycle of schistosomes the mammalian hosts are exposed to several biomolecules that are excreted/secreted from the parasite infective stage, named cercariae, from their tegument, present in adult and larval stages, and finally from their eggs. These molecules can induce the activation and modulation of innate and adaptive responses as well as enabling the evasion of the parasite from host defense mechanisms. Immunomodulatory effects of helminth infections and egg molecules are clear, as well as their ability to downregulate proinflammatory cytokines, upregulate anti-inflammatory cytokines, and drive a Th2 type of immune response. We believe that schistosomes can be used as a model to understand the potential applications of helminths and helminth-derived molecules against autoimmune and inflammatory diseases.

Identifying the immunomodulatory components of helminths.

Immunomodulatory components of helminths offer great promise as an entirely new class of biologics for the treatment of inflammatory diseases. Here, we discuss the emerging themes in helminth-driven immunomodulation in the context of therapeutic drug discovery. We broadly define the approaches that are currently applied by researchers to identify these helminth molecules, highlighting key areas of potential exploitation that have been mostly neglected thus far, notably small molecules. Finally, we propose that the investigation of immunomodulatory compounds will enable the translation of current and future research efforts into potential treatments for autoimmune and allergic diseases, while at the same time yielding new insights into the molecular interface of host-parasite biology.

Lectins with anti-HIV activity: a review.

Lectins including flowering plant lectins, algal lectins, cyanobacterial lectins, actinomycete lectin, worm lectins, and the nonpeptidic lectin mimics pradimicins and benanomicins, exhibit anti-HIV activity. The anti-HIV plant lectins include Artocarpus heterophyllus (jacalin) lectin, concanavalin A, Galanthus nivalis (snowdrop) agglutinin-related lectins, Musa acuminata (banana) lectin, Myrianthus holstii lectin, Narcissus pseudonarcissus lectin, and Urtica diocia agglutinin. The anti-HIV algal lectins comprise Boodlea coacta lectin, Griffithsin, Oscillatoria agardhii agglutinin. The anti-HIV cyanobacterial lectins are cyanovirin-N, scytovirin, Microcystis viridis lectin, and microvirin. Actinohivin is an anti-HIV actinomycete lectin. The anti-HIV worm lectins include Chaetopterus variopedatus polychaete marine worm lectin, Serpula vermicularis sea worm lectin, and C-type lectin Mermaid from nematode (Laxus oneistus). The anti-HIV nonpeptidic lectin mimics comprise pradimicins and benanomicins. Their anti-HIV mechanisms are discussed.

Bioinformatic analysis for structure and function of TCTP from Spirometra mansoni.

OBJECTIVE: To predict structure and function of translationally controlled tumor protein (TCTP) from Spirometra mansoni by bioinformatics technology, and to provide a theoretical basis for further study. METHODS: Open reading frame (ORF) of EST sequence from Spirometra mansoni was obtained by ORF finder and was translated into amino acid residue by DNAclub. The structure domain was analyzed by Blast. By the method of online analysis tools: Protparam, InterProScan, protscale, SignalP-3.0, PSORT II, BepiPred, TMHMM, VectorNTI Suite 9 packages and Phyre2, the structure and function of the protein were predicted and analyzed. RESULTS: The results showed that the EST sequence was Sm TCTP with 173 amino acid residues, theoretical molecular weight was 19 872.0 Da. The protein has the closest evolutionary status with Clonorchis sinensis, Schistosoma mansoni, and Schistosoma japonicum. Then it had no signal peptide site and transmembrane domain. Secondary structure of TCTP contained two α -helices and eight ß -strands. CONCLUSIONS: Sm TCTP was a variety of biological functions of protein that may be used as a vaccine candidate molecule and drug target.

Prerequisites for the pharmaceutical industry to develop and commercialise helminths and helminth-derived product therapy.

During the past 10 years, immunologists, epidemiologists and parasitologists have made many new exciting discoveries in the field of helminth-mediated immune regulation. In addition, many animal experiments have shown that certain helminths or products derived from helminths can protect mice from developing allergic or autoimmune disease. Some clinical trials utilising Trichuris suis or Necator americanus for the treatment of allergic disorders and inflammatory bowel disease have been conducted. The outcomes of these trials suggest that they may be used to treat these disorders. However, to date no helminth therapy is routinely being applied to patients and no helminth-derived product therapy has been developed. In order to bring new drugs to the market and shoulder the enormous costs involved in developing such therapies, pharmaceutical companies need to be involved. However, currently the resources from the pharmaceutical industry devoted to this concept are relatively small and there are good reasons why the industry may have been reluctant to invest in developing these types of therapies. In this review article, the hurdles that must be overcome before the pharmaceutical industry might invest in these novel therapies are outlined.

Bioaccumulation of six PCB indicator congeners in a heavily polluted water reservoir in Eastern Slovakia: tissue-specific distribution in fish and their parasites.

Concentrations of six indicator PCB congeners (IUPAC nos. 28, 52, 101, 138, 153, and 180) were measured in several organs and adipose tissue of a freshwater predatory fishes (European perch, northern pike, pike perch, wels catfish) as well as in nonpredators (common carp, freshwater bream, goldfish, white bream) and in acanthocephalan Acanthocephalus lucii from the water reservoir Zemplínska sírava (Eastern Slovakia), which is considered to be one of the most PCB-contaminated places in Europe. Concentration of PCBs was determined by capillary gas chromatography in samples from May to September 2009. The two-way main-effect ANOVA confirmed that feeding habits of fish (P < 0.00001) and peculiarity of individual fish organs (P < 0.01) affect PCB bioaccumulation. The total amount of PCBs was significantly higher (P < 0.05) in predators compared to nonpredators. Tissue-specific differences were found in PCB accumulation in both fish groups. PCBs were predominantly accumulated in the liver and hard roe. Individual congeners were not distributed homogeneously within the investigated organs and adipose tissue. PCB 153 was present in higher concentrations than the other congeners in all fish organs as well as in adipose tissue comprising an average 31 and 34 % of ΣPCB in predators and nonpredators, respectively. Acanthocephalans, attached to the intestine of perch, absorbed significantly higher concentrations of PCBs (P < 0.001) than the muscles, liver, kidney, brain, and adipose tissue of their host. About 20 times lower amount of PCBs was detected in the liver and almost 3 times in muscles of infected perch. Data on PCB accumulation in perch infected with acanthocephalans demonstrated a decline of PCB values in all organs as well as in adipose tissue compared to noninfected fish. About 20 times lower amount of PCBs was detected in the liver and almost 3 times in muscles of infected perch. Present results could indicate that some parasitic organisms may influence positively their hosts in PCB-contaminated environment.