Search results for "PROTOZOAN"
showing 10 items of 135 documents
Paratransgenic manipulation of a tsetse microRNA alters the physiological homeostasis of the fly’s midgut environment
2021
Tsetse flies are vectors of parasitic African trypanosomes, the etiological agents of human and animal African trypanosomoses. Current disease control methods include fly-repelling pesticides, fly trapping, and chemotherapeutic treatment of infected people and animals. Inhibiting tsetse’s ability to transmit trypanosomes by strengthening the fly’s natural barriers can serve as an alternative approach to reduce disease. The peritrophic matrix (PM) is a chitinous and proteinaceous barrier that lines the insect midgut and serves as a protective barrier that inhibits infection with pathogens. African trypanosomes must cross tsetse’s PM in order to establish an infection in the fly, and PM struc…
Unnatural amino acids increase activity and specificity of synthetic substrates for human and malarial cathepsin C
2014
Mammalian cathepsin C is primarily responsible for the removal of N-terminal dipeptides and activation of several serine proteases in inflammatory or immune cells, while its malarial parasite ortholog dipeptidyl aminopeptidase 1 plays a crucial role in catabolizing the hemoglobin of its host erythrocyte. In this report, we describe the systematic substrate specificity analysis of three cathepsin C orthologs from Homo sapiens (human), Bos taurus (bovine) and Plasmodium falciparum (malaria parasite). Here, we present a new approach with a tailored fluorogenic substrate library designed and synthesized to probe the S1 and S2 pocket preferences of these enzymes with both natural and a broad ran…
Plant protein phosphorylation monitored by capillary liquid chromatography–element mass spectrometry
2007
Abstract Many essential cellular functions such as growth rate, motility, and metabolic activity are linked to reversible protein phosphorylation, since they are controlled by signaling cascades based mainly on phosphorylation/dephosphorylation events. Quantification of global or site-specific protein phosphorylation is not straightforward with standard proteomic techniques. The coupling of capillary liquid chromatography (μLC) with ICP-MS (inductively coupled plasma-mass spectrometry) is a method which allows a quantitative screening of protein extracts for their phosphorus and sulfur content, and thus provides access to the protein phosphorylation degree. In extension of a recent pilot st…
Vaccination with TAT-Antigen Fusion Protein Induces Protective, CD8+ T Cell-Mediated Immunity Against Leishmania Major
2010
In murine leishmaniasis, healing is mediated by IFN-γ-producing CD4 + and CD8 + T cells. Thus, an efficacious vaccine should induce Th1 and Tc1 cells. Dendritic cells (DCs) pulsed with exogenous proteins primarily induce strong CD4-dependent immunity; induction of CD8 responses has proven to be difficult. We evaluated the immunogenicity of fusion proteins comprising the protein transduction domain of HIV-1 TAT and the Leishmania antigen LACK ( Leishmania homolog of receptors for activated C kinase), as TAT-fusion proteins facilitate major histocompatibility complex class I-dependent antigen presentation. In vitro , TAT–LACK-pulsed DCs induced stronger proliferation of Leishmania -specific C…
Speculation on whether a vaccine against cryptosporidiosis is a reality or fantasy
1999
In this paper the authors question whether the development of a vaccine against cryptosporidiosis could be taken into consideration. The necessity and feasibility of such a vaccine for human and veterinary application is discussed. Developmental stages within the life cycle of the parasite that might act as possible targets for vaccine development are summarised, as well as the target antigens offered by molecular biology and immunology studies. Vaccination trials against cryptosporidiosis carried out so far, including the active and passive immunisation approach, are also overviewed. It seems that with respect to a Cryptosporidium vaccine two target groups can be considered: children of th…
Aplicación de la topología molecular en la predicción de la actividad antiprotozoaria de derivados del benzimidazol
2013
Se ha aplicado la topología molecular a la búsqueda de nuevos derivados del benzimidazol con actividad antiprotozoaria frente a Trichomonas vaginalis y Giardia intestinalis. A partir de los resultados del análisis lineal discriminante, dos modelos basados en cuatro descriptores (en el caso de T. vaginalis) y cinco descriptores (en el caso de G. intestinalis) demostraron ser capaces de predecir correctamente la actividad de cada compuesto analizado. Después de un cribado virtual aplicando ambos modelos, se proponen nuevas estructuras químicas potencialmente activas frente a T. vaginalis y G. intestinalis. Molecular topology has been applied to search for new benzimidazole derivatives with an…
Machine learning-based models to predict modes of toxic action of phenols to Tetrahymena pyriformis.
2017
The phenols are structurally heterogeneous pollutants and they present a variety of modes of toxic action (MOA), including polar narcotics, weak acid respiratory uncouplers, pro-electrophiles, and soft electrophiles. Because it is often difficult to determine correctly the mechanism of action of a compound, quantitative structure-activity relationship (QSAR) methods, which have proved their interest in toxicity prediction, can be used. In this work, several QSAR models for the prediction of MOA of 221 phenols to the ciliated protozoan Tetrahymena pyriformis, using Chemistry Development Kit descriptors, are reported. Four machine learning techniques (ML), k-nearest neighbours, support vector…
A tRNA half modulates translation as stress response in Trypanosoma brucei
2019
In the absence of extensive transcription control mechanisms the pathogenic parasite Trypanosoma brucei crucially depends on translation regulation to orchestrate gene expression. However, molecular insight into regulating protein biosynthesis is sparse. Here we analyze the small non-coding RNA (ncRNA) interactome of ribosomes in T. brucei during different growth conditions and life stages. Ribosome-associated ncRNAs have recently been recognized as unprecedented regulators of ribosome functions. Our data show that the tRNAThr 3´half is produced during nutrient deprivation and becomes one of the most abundant tRNA-derived RNA fragments (tdRs). tRNAThr halves associate with ribosomes and pol…
Frequency of exposure of endangered Caspian seals to Canine distemper virus, Leptospira interrogans, and Toxoplasma gondii
2017
Canine distemper virus (CDV), Leptospira interrogans, and Toxoplasma gondii are potentially lethal pathogens associated with decline in marine mammal populations. The Caspian Sea is home for the endangered Caspian seal (Pusa caspica). In the late 1990s and early 2000s, CDV caused a series of mortality events involving at least several thousand Caspian seals. To assess current infection status in Caspian seals, we surveyed for antibodies to three pathogens with potential to cause mortality in marine mammals. During 2015-2017, we tested serum samples from 36, apparently healthy, Caspian seals, accidentally caught in fishing nets in the Caspian Sea off Northern Iran, for antibodies to CDV, L. …
mp23, a Theileria parva transmembrane protein with homology to the protein disulfide isomerase family
2002
The protozoan parasite Theileria parva (Apicomplexa) causes the bovine disease East Coast Fever in endemic areas in Subsaharan Africa. The intralymphocytic schizont stage is largely responsible for the pathogenicity and induces a transformed phenotype in host cells [1]. Current evidence supports a model in which the schizont perturbs the immune response by inducing production of cytokines and stimulating the growth of parasitized cells [2]. We were interested to identify parasite proteins involved in parasite/host interaction and have described earlier a screening procedure for identification of schizont stage-exported proteins based on cell-free expression of cDNA and testing for transloca…