7,690 research outputs found

    Production, Functional Characterization and Inhibition of Carbonic Anhydrases of Parasites

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    Hiilihappoanhydraasit (carbonic anhydrase, CA) ovat metalloentsyymej√§, joita esiintyy kaikkialla elollisessa luonnossa. Niiden teht√§v√§ on katalysoida elint√§rke√§√§ k√§√§nteist√§ reaktiota: hiilidioksidin hydraatiota hiilihapoksi (CO2 + H2O ‚áč H2CO3 ‚áč HCO3- + H+). Reaktio on osana monissa fysiologisissa ja metabolisissa prosesseissa, kuten happo-em√§stasapainon s√§√§telyss√§, glukoneogeneesissa ja yhteytt√§misess√§. Hiilihappoanhydraasit jaetaan yhteens√§ kahdeksaan perheeseen, joista ihmisill√§ esiintyy vain ensimm√§isen√§ l√∂ydetty√§ őĪ-entsyymiperhett√§. Monilla taudinaiheuttajilla, kuten bakteereilla ja loisilla, on my√∂s muiden hiilihappoanhydraasiperheiden proteiineja. Schistosoma mansoni on suolistotulehdusta aiheuttava halkiomato, jota esiintyy endeemisen√§ monilla trooppisilla ja subtrooppisilla seuduilla. Entamoeba histolytica ja Acanthamoeba castellanii ovat ihmisille infektioita aiheuttavia ameboja. E. histolytica aiheuttaa suolistotulehdusta ja A. castellanii p√§√§asiassa sarveiskalvon tulehdusta, sek√§ immuunipuutteisille henkil√∂ille my√∂s syvi√§ infektioita. Yhteist√§ n√§ille loisille on, ett√§ niiden diagnostiikassa tai hoidossa on puutteita, ja ne ovat globaalisti eritt√§in yleisi√§. Niiden aiheuttamat sairaudet voivat olla tappavia, ja aiheuttavat lievimmill√§√§nkin merkitt√§v√§√§ el√§m√§nlaadullista haittaa. V√§it√∂skirjatutkimukseni tavoitteena on l√∂yt√§√§ nopeampi menetelm√§ tunnistaa A. castellanii biologisesta n√§ytteest√§ sek√§ l√∂yt√§√§ uusia potentiaalisia l√§√§keainemolekyylej√§ n√§iden kolmen loisen aiheuttamien sairauksien tehokkaammaksi hoitamiseksi. V√§it√∂stutkimuksessani tuotin E. histolytican ja S. mansonin ő≤-hiilihappoanhydraasit Escherichia coli -bakteereissa. Tutkimme hiilihappoanhydraasien inhibiittorien vaikutusta tuotettuihin entsyymeihin, ja l√∂ysimme useita lupaavia inhibiittoreita. Lis√§ksi kehitimme uuden nopean diagnostisen menetelm√§n A. castellaniin havaitsemiseksi n√§ytteest√§, sill√§ nykyinen ameban viljelyyn perustuva menetelm√§ on kliiniseen diagnostiikkaan liian hidas. Nykyiset A. castellaniin aiheuttamien infektioiden hoitoon k√§ytetyt l√§√§kkeet ovat vain kohtalaisen tehokkaita ja niihin liittyy useita haittavaikutuksia, joten kehitimme uuden menetelm√§n uusien l√§√§keaineiden etsimist√§ varten ja testasimme useita, jo kliinisess√§ k√§yt√∂ss√§ olevia hiilihappoanhydraasin est√§ji√§ menetelm√§ll√§mme. Havaitsimme, ett√§ dorsolamidi ja asetatsoliamidi ovat lupaavia uusia vaihtoehtoja akantamebakeratiitin hoitamiseksi. Niiden etuna on pitk√§√§n jatkunut k√§ytt√∂ ihmispotilaiden muiden sairauksien hoidossa, joten niiden haitta- ja sivuvaikutukset ovat tunnettuja. Valitettavasti asetatsoliamidi on vain kohtalaisen tehokas inhiboimaan E. histolytican ja S. mansonin ő≤-hiilihappoanhydraaseja. Dorsolamidi on tehokas inbiittori S. mansonin ő≤-hiilihappoanhydraasia vastaan, toisin kuin E. histolytican ő≤-hiilihappoanhydraasia se inhiboi huonosti. Onneksi moni muu inhibiittori on tehokas est√§m√§√§n niiden molempien toimintaa. T√§m√§ v√§it√∂skirja lis√§√§ tietoa ja mahdollisuuksia hy√∂dynt√§√§ hiilihappoanhydraaseja loisinfektioiden diagnostiikassa ja hoidossa.Carbonic anhydrases (CAs, EC 4.2.1.1) are metalloenzymes that can be found in almost all living organisms. They catalyze a vital chemical reaction: the reversible hydration of carbon dioxide (CO2 + H2O ‚áč H2CO3 ‚áč HCO3‚ąí + H+). It is part of multiple physiological and metabolic processes, such as p regulation, gluconeogenesis and photosynthesis. CAs are divided into eight families, from which the human genome only involves őĪ-CAs. Many pathogens, such as bacteria and parasites, also have CA enzymes from other families. Schistosoma mansoni is a parasitic blood fluke that causes intestinal infection in many tropical and subtropical areas. Entamoeba histolytica and Acanthamoeba castellanii are amoebae that cause different infections in humans. E. histolytica causes intestinal infection, and A. castellanii mainly infects the cornea but also causes invasive infections in immunocompromised people. The infections of these parasites are common globally, and unfortunately, the diagnosis and treatment are often delayed. The infections can be lethal, and at their mildest, they cause a significant reduction in the quality of life. My study aims to find a faster and more effective way to detect A. castellanii from a biological sample and discover new potential drug candidates to treat these parasitic infections. In my thesis, I produced the ő≤-CAs of E. histolytica and S. mansoni using Escherichia coli as a protein production organism. We studied the inhibitory effects of many known CA inhibitors and identified several promising candidates or potential leads for further development. In addition, we developed a novel rapid diagnostic method to detect A. castellanii from a biological sample. The novel method could replace the current gold standard, sample culture, which is slow in clinical diagnostics. We established a new method to investigate potential drug candidates for treating A. castellanii, as the current treatment options are only moderately effective and have many adverse side effects. By this method, we tested several clinically used CA inhibitors with interesting outcomes. Dorzolamide and acetazolamide were found to be new promising options for treating Acanthamoeba keratitis. The advantage of these drugs is also the long use history with human patients in treating other conditions, which has made the side effects and risks very familiar to medical staff. Unfortunately, acetazolamide was only moderately effective against the ő≤-CAs of S. mansoni and E. histolytica, as was dorzolamide against the ő≤-CA of E. histolytica. In contrast, dorzolamide was an effective inhibitor against the ő≤-CA of S. mansoni. We also found many other effective inhibitors against the ő≤-CAs of E. histolytica and S. mansoni. This thesis increases the knowledge and options to use the CAs of parasites to diagnose and treat infections caused by parasites

    Human growth factor-mediated signalling through lipid rafts regulates stem cell proliferation, development and survival of Schistosoma mansoni

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    Although the mechanisms by which schistosomes grow and develop in humans are poorly defined, their unique outer tegument layer, which interfaces with host blood, is considered vital to homeostasis of the parasite. Here, we investigated the importance of tegument lipid rafts to the biology of Schistosoma mansoni in the context of host‚Äďparasite interactions. We demonstrate the temporal clustering of lipid rafts in response to human epidermal growth factor (EGF) during early somule development, concomitant with the localization of anteriorly orientated EGF receptors (EGFRs) and insulin receptors, mapped using fluorescent EGF/insulin ligand. Methyl-ő≤-cyclodextrin (Mő≤CD)-mediated depletion of cholesterol from lipid rafts abrogated the EGFR/IR binding at the parasite surface and led to modulation of protein kinase C, extracellular signal-regulated kinase, p38 mitogen-activated protein kinase and Akt signalling pathways within the parasite. Furthermore, Mő≤CD-mediated lipid raft disruption, and blockade of EGFRs using canertinib, profoundly reduced somule motility and survival, and attenuated stem cell proliferation and somule growth and development particularly to the fast-growing liver stage. These findings provide a novel paradigm for schistosome development and vitality in the host, driven through host‚Äďparasite interactions at the tegument, that might be exploitable for developing innovative therapeutic approaches to combat human schistosomiasis

    Emerging role of extracellular vesicles in veterinary practice: novel opportunities and potential challenges

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    Extracellular vesicles are nanoscale vesicles that transport signals between cells, mediating both physiological and pathological processes. EVs facilitate conserved intercellular communication. By transferring bioactive molecules between cells, EVs coordinate systemic responses, regulating homeostasis, immunity, and disease progression. Given their biological importance and involvement in pathogenesis, EVs show promise as biomarkers for veterinary diagnosis, and candidates for vaccine production, and treatment agents. Additionally, different treatment or engineering methods could be used to boost the capability of extracellular vesicles. Despite the emerging veterinary interest, EV research has been predominantly human-based. Critical knowledge gaps remain regarding isolation protocols, cargo loading mechanisms, in vivo biodistribution, and species-specific functions. Standardized methods for veterinary EV characterization and validation are lacking. Regulatory uncertainties impede veterinary clinical translation. Advances in fundamental EV biology and technology are needed to propel the veterinary field forward. This review introduces EVs from a veterinary perspective by introducing the latest studies, highlighting their potential while analyzing challenges to motivate expanded veterinary investigation and translation

    The histone binding capacity of SPT2 controls chromatin structure and function in Metazoa

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    Histone chaperones control nucleosome density and chromatin structure. In yeast, the H3-H4 chaperone Spt2 controls histone deposition at active genes but its roles in metazoan chromatin structure and organismal physiology are not known. Here we identify the Caenorhabditis elegans ortholog of SPT2 (CeSPT-2) and show that its ability to bind histones H3-H4 is important for germline development and transgenerational epigenetic gene silencing, and that spt-2 null mutants display signatures of a global stress response. Genome-wide profiling showed that CeSPT-2 binds to a range of highly expressed genes, and we find that spt-2 mutants have increased chromatin accessibility at a subset of these loci. We also show that SPT2 influences chromatin structure and controls the levels of soluble and chromatin-bound H3.3 in human cells. Our work reveals roles for SPT2 in controlling chromatin structure and function in Metazoa.</p

    Host-parasite dialogue: fecundity compensation mechanisms of Fissurella crassa

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    Parasites can alter the reproductive performance of their hosts, and to avoid or mitigate the resulting fitness loss, hosts may increase their current reproductive output to compensate for the future loss due to the parasitic infection. Fecundity compensation can be exploited by parasites for their own transmission (exploitation of host compensatory responses by parasites). However, this phenomenon has rarely been reported in second intermediate hosts of trematodes and its mechanisms and consequences largely unexplored. Along the east coast of the South Pacific, the second intermediate host, the mollusk Fissurella crassa, has been observed to display higher muscular foot, greater shell length and weight, and a higher gonadosomatic index when parasitized by metacercariaes of Proctoeces humboldti compared to non-parasitized hosts. In this study, we examined the histology, biochemistry (glucose, lipids, and proteins), and levels of sex hormones (estradiol and progesterone) in both parasitized and non-parasitized female individuals of F. crassa. Our findings revealed that the gonad of parasitized limpets had a higher density of oocytes, but these had a smaller individual area. Additionally, the gonadal tissue of parasitized limpets exhibited lower glucose content but higher lipid content. Notably, the levels of progesterone increased with parasite intensity. These results suggest that F. crassa possesses the ability to compensate for the negative effects of parasites by increasing the number of oocytes through biochemical and hormonal mechanisms. Our study contributes to the limited research on the impact of metacercariae on the reproduction of second intermediate hosts. Furthermore, we discuss how these changes in parasitized limpets could benefit parasite transmission

    High sensitivity of mobile phone microscopy screening for Schistosoma haematobium in Azagui√©, C√īte d'Ivoire

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    Schistosomiasis infections continue to impact African settings disproportionately, and there is an urgent need for novel tools to evaluate infection control and elimination strategies at the community level. Mobile phone microscopes are portable and semiautomated devices with multiple applications for screening neglected tropical diseases. In a community-based schistosomiasis screening program in Azaguie, Cote d'Ivoire, mobile phone microscopy demonstrated a sensitivity of 85.7% (95% CI: 69.7-95.2%) and specificity of 93.3% (95% CI: 87.7-96.9%) for Schistosoma haematobium identification compared with conventional light microscopy, and 95% sensitivity (95% CI: 74.1-99.8%) with egg concentrations of five or more per 10 mL of urine. Mobile phone microscopy is a promising tool for schistosomiasis control and elimination efforts

    Molluscicidal and Larvicidal Potency of <i>N</i>-Heterocylic Analogs against <i>Biomophalaria alexandrina</i> Snails and <i>Schistosoma mansoni</i> Larval Stages

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    This work describes the synthesis of quinoline-based N--heterocyclic arenes and their biological evaluation as molluscicides against adult Biomophalaria alexandrina snails as well as larvicides against Schistosoma mansoni larvae (miracidia and cercariae). Molecular docking studies were demonstrated to investigate their affinity for cysteine protease protein as an interesting target for antiparasitics. Compound AEAN showed the best docking results followed by APAN in comparison to the co-crystallized ligand D1R reflected by their binding affinities and RMSD values. The egg production, hatchability of B. alexandrina snails and ultrastructural topography of S. mansoni cercariae using SEM were assessed. Biological evaluations (hatchability and egg-laying capacity) revealed that the quinoline hydrochloride salt CAAQ was the most effective compound against adult B. alexandrina snails, whereas the indolo-quinoline derivative APAN had the most efficiency against miracidia, and the acridinyl derivative AEAA was the most effective against cercariae and caused 100% mortality. CAAQ and AEAA were found to modulate the biological responses of B. alexandrina snails with/without S. mansoni infection and larval stages that will affect S. mansoni infection. AEAA caused deleterious morphological effects on cercariae. CAAQ caused inhibition in the number of eggs/snail/week and reduced reproductive rate to 43.8% in all the experimental groups. CAAQ and AEAA can be recommended as an effective molluscicide of plant origin for the control program of schistosomiasis

    Gold complex compounds that inhibit drug-resistant Staphylococcus aureus by targeting thioredoxin reductase

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    IntroductionThere is a significant need for new antimicrobial compounds that are effective against drug-resistant microbes. Thioredoxin reductase (TrxR) is critical in redox homeostasis and was identified as a potential drug target and confirmed through inhibition by compounds auranofin and Bay11-7085.MethodsAdditional TrxR inhibitors were designed and found to exhibit antimicrobial activity against Gram-positive (Enterococcus faecium and Staphylococcus aureus) and glutathione-deficient bacteria (Helicobacter pylori). Investigational compounds were tested for antimicrobial activity, anti-biofilm efficacy, target impact, and cytotoxicity.ResultsThe first-generation molecules AU1 and AU5 inhibited TrxR activity and inhibited methicillin-resistant S. aureus strain MW2 with minimal inhibitory concentrations (MIC) of 0.125 and 0.5 őľg/mL, respectively. In an S. aureus enzymatic assay, AU1 inhibited TrxR enzymatic activity in a dose-dependent manner causing a decrease in intracellular free thiols. In addition, biofilm studies demonstrated that AU1 and AU5 reduced biofilm formation at 1X MIC and disrupted mature biofilms at 4X MIC. Cytotoxicity profiles were created using human cell lines and primary cells with LD50 exceeding MICs by at least 12X.DiscussionThus, AU1 and AU5 were TrxR inhibitors that yielded low-concentration antimicrobial activity impacting S. aureus in planktonic and biofilm forms with limited toxic liability

    New technologies to study helminth development and host-parasite interactions

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    How parasites develop and survive, and how they stimulate or modulate host immune responses are important in understanding disease pathology and for the design of new control strategies. Microarray analysis and bulk RNA sequencing have provided a wealth of data on gene expression as parasites develop through different life-cycle stages and on host cell responses to infection. These techniques have enabled gene expression in the whole organism or host tissue to be detailed, but do not take account of the heterogeneity between cells of different types or developmental stages, nor the spatial organisation of these cells. Single-cell RNA-seq (scRNA-seq) adds a new dimension to studying parasite biology and host immunity by enabling gene profiling at the individual cell level. Here we review the application of scRNA-seq to establish gene expression cell atlases for multicellular helminths and to explore the expansion and molecular profile of individual host cell types involved in parasite immunity and tissue repair. Studying host-parasite interactions in vivo is challenging and we conclude this review by briefly discussing the applications of organoids (stem-cell derived mini-tissues) to examine host-parasite interactions at the local level, and as a potential system to study parasite development in vitro. Organoid technology and its applications have developed rapidly, and the elegant studies performed to date support the use of organoids as an alternative in vitro system for research on helminth parasites

    Immunomodulatory properties of helminth-produced molecules and their effect during autoimmune and chronic inflammatory diseases

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    Parasitic helminths produce excretion/secretion products (ESP) that affect the host's immune system to prevent damage or exclusion of the parasite. In recent decades, individual ESP molecules have been the focus of research for the treatment of autoimmune and chronic inflammatory diseases due to their immunomodulatory potential. Diseases that have been investigated in this context include ulcerative colitis, multiple sclerosis, type 1 diabetes, rheumatoid arthritis and allergic asthma. Among the pleiad of helminths and their immunomodulatory molecules, it is worth mentioning Acanthocheilonema viteae (Av17), Ancylostoma caninum (NIF), Ascaris lumbricoides (Al-CPI), Brugia malayi (BMCys), Clonorchis sinensis (CsStefin-1), Fasciola hepatica (FhHDM-1), Heligmosomoides polygyrus (HpTGM), Schistosoma japonicum (SjCystatin) and Schistosoma mansoni (Omega-1). The main effects of these molecules on the host immune system include affecting the function of dendritic cells and macrophages, influencing cytokine production and reducing the Th1 immune response, which usually leads to alleviation of disease symptoms. Based on the current state of knowledge, it is not yet certain how the molecules will work in treating patients and whether they will have the same effect when administered in the long term. Despite...Parazitińćt√≠ helminti produkuj√≠ exkreńćnńõ/sekreńćn√≠ produkty (ESP), kter√© ovlivŇąuj√≠ imunitn√≠ syst√©m hostitele, aby zabr√°nily poŇ°kozen√≠ nebo vylouńćen√≠ parazita. V pro jejich imunomodulańćn√≠ potenci√°l jednotliv√© molekuly ESP pŇôedmńõtem v√Ĺzkumu l√©ńćby autoimunitn√≠ch a chronick√Ĺch z√°nńõtliv√Ĺch onemocnńõn√≠. Mezi onemocnńõn√≠, kter√© jsou v kontextu zkoum√°na, patŇô√≠ ulcer√≥zn√≠ kolitida, roztrouŇ°en√° skler√≥za, diabetes 1.typu, revmatoidn√≠ plej√°dy helmintŇĮ a jejich imunomodulańćn√≠ch molekul stoj√≠ za hlavn√≠m √ļńćinkŇĮm tńõchto molekul na imunitn√≠ syst√©m hostitele se Ňôad√≠ ovlivnńõn√≠ funkce dendritick√Ĺch bunńõk a makrof√°gŇĮ, ovlivnńõn√≠ produkce cytokinŇĮ a sn√≠Ňĺen√≠ Th1 imunitn√≠ odpovńõdi, coŇĺ vńõtŇ°in zm√≠rnńõn√≠ pŇô√≠znakŇĮ nemoci. Podle souńćasn√©ho stavu pozn√°n√≠ zat√≠m nen√≠ jist√©, jak budou molekuly fungovat pŇôi l√©ńćbńõ pacientŇĮ a jestli budou m√≠t stejn√Ĺ √ļńćinek i pŇôi dlouhodob√©m pod√°v√°n√≠. Navzdory tomu d√≠ky v√Ĺzkumu jejich vyuŇĺit√≠ pŇôi l√©ńćbńõ autoimunitn√≠ch a chronick√Ĺch onemocnńõn√≠ vznik√° Ňôada slibn√Ĺch kandid√°tŇĮ na l√©ńćiva. Kl√≠ńćov√° slova: helminti, imunomodulańćn√≠ molekuly, autoimunitn√≠ onemocnńõn√≠, alergick√° onemocnńõn√≠, terapie, profylaxeKatedra parazitologieDepartment of ParasitologyFaculty of SciencePŇô√≠rodovńõdeck√° fakult
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