scholarly journals 895 Trichomonas vaginalis exosomes deliver cargo to host cells and mediate host: Parasite interactions

2018 ◽  
Vol 138 (5) ◽  
pp. S152
Author(s):  
O. Twu ◽  
N. de Miguel ◽  
G. Lustig ◽  
G. Stevens ◽  
A. Vashishit ◽  
...  
Keyword(s):  
Trichomonas Vaginalis ◽  
Host Cells ◽  
Host Parasite Interactions ◽  
Host Parasite

scholarly journals Trichomonas vaginalis: current understanding of host–parasite interactions

2011 ◽  
Vol 51 ◽  
pp. 161-175 ◽  
Author(s):  
Christopher M. Ryan ◽  
Natalia de Miguel ◽  
Patricia J. Johnson
Keyword(s):  
Drug Targets ◽  
Trichomonas Vaginalis ◽  
Molecular Data ◽  
Host Cells ◽  
Current Status ◽  
Rational Approach ◽  
Sexually Transmitted ◽  
Host Parasite Interactions ◽  
Future Challenges ◽  
Host Parasite

Trichomonas vaginalis is a sexually transmitted obligate extracellular parasite that colonizes the human urogenital tract. Despite being of critical importance to the parasite's survival relatively little is known about the mechanisms employed by T. vaginalis to establish an infection and thrive within its host. Several studies have focused on the interaction of the parasite with host cells and extracellular matrix, identifying multiple suspected T. vaginalis adhesins. However, with the exception of its surface lipophosphoglycan, the evidence supporting a role in adhesion is indirect or controversial for many candidate molecules. The availability of the T. vaginalis genome sequence paved the way for genomic analyses to search for proteins possibly involved in host–parasite interactions. Several proteomic analyses have also provided insight into surface, soluble and secreted proteins that may be involved in Trichomonas pathogenesis. Although the accumulation of molecular data allows for a more rational approach towards identifying drug targets and vaccine candidates for this medically important parasite, a continued effort is required to advance our understanding of its biology. In the present chapter, we review the current status of research aimed at understanding T. vaginalis pathogenesis. Applied experimental approaches, an overview of significant conclusions drawn from this research and future challenges are discussed.

scholarly journals Trichomonas vaginalis Exosomes Deliver Cargo to Host Cells and Mediate Host∶Parasite Interactions

2013 ◽  
Vol 9 (7) ◽  
pp. e1003482 ◽  
Author(s):  
Olivia Twu ◽  
Natalia de Miguel ◽  
Gila Lustig ◽  
Grant C. Stevens ◽  
Ajay A. Vashisht ◽  
...  
Keyword(s):  
Trichomonas Vaginalis ◽  
Host Cells ◽  
Host Parasite Interactions ◽  
Host Parasite

scholarly journals Critical aspects of phytoalexins in potato

1987 ◽  
Vol 59 (3) ◽  
pp. 217-230
Author(s):  
Sture Brishammer
Keyword(s):  
Host Cells ◽  
Potato Tubers ◽  
Inhibitory Effects ◽  
Host Parasite Interactions ◽  
Different Types ◽  
Endogenous Elicitor ◽  
Artificial Inoculations ◽  
Host Parasite ◽  
Critical Aspects

Phytoalexins in potato are sesquiterpenoid substances produced in response to infections and are believed to help plants resist attack by pathogens. However, these compounds appear in response to compatible as well as incompatible interactions and only accumulate in the tubers. The amounts of phytoalexins produced depend on the physiological condition of the tubers. Young tubers don’t get easily infected with Phytophthora infestans even though they synthesize extremely small amounts of phytoalexins. Furthermore, confusion as to the identity of specific races and the propensity for a given race to produce different effects in the same type of host makes it extremely difficult to predict host-parasite interactions with any acceptable degree of accuracy. It is doubtful that the production of phytoalexins in response to artificial inoculations is representative of that occurring in natural infections. Markedly different types of pathogens induce synthesis of same substances in the host cells. It therefore seems most probable that all the phytoalexins are synthesized in response to stimulation by an endogenous elicitor. Little knowledge is available regarding the biosynthesis of these sesquiterpenes, and many previous determinations have presumably been erroneous. When potato tubers were inoculated with the late blight fungus, secondarily appearing bacteria were not retarded, despite the presence of phytoalexins. There is no generally accepted hypothesis describing the mechanism by which phytoalexins inhibit pathogens and no distinction has been made between the effects on necrotrophs and biotrophs. Adequate bioassays capable of measuring the effects of inhibition have yet to be developed, thus far, no convincing inhibitory effects have been reported. During purification of the phytoalexins there is a high risk for artifact forming, implying that specific compounds cannot be detected with certainty. Moreover, present analytical methods must be improved before we can determine how phytoalexins act in vivo. Probably, phytoalexins are synthesized at a stage in the infection too late to be able to restrict its expansion with the tissues of the host. Phytoalexins are restricted to the attacked parts of the tubers and there is no evidence indicating that these compounds pose any health risks when present in potatoes used for consumption.

scholarly journals Expanding the antimalarial toolkit: Targeting host–parasite interactions

2016 ◽  
Vol 213 (2) ◽  
pp. 143-153 ◽  
Author(s):  
Jean Langhorne ◽  
Patrick E. Duffy
Keyword(s):  
First Generation ◽  
Host Cells ◽  
Mammalian Host ◽  
Drug Resistant ◽  
Intracellular Growth ◽  
Partial Protection ◽  
Anopheles Mosquitoes ◽  
Host Parasite Interactions ◽  
New Research ◽  
Host Parasite

Recent successes in malaria control are threatened by drug-resistant Plasmodium parasites and insecticide-resistant Anopheles mosquitoes, and first generation vaccines offer only partial protection. New research approaches have highlighted host as well as parasite molecules or pathways that could be targeted for interventions. In this study, we discuss host–parasite interactions at the different stages of the Plasmodium life cycle within the mammalian host and the potential for therapeutics that prevent parasite migration, invasion, intracellular growth, or egress from host cells, as well as parasite-induced pathology.

scholarly journals Adhesion of Tritrichomonas foetus to Bovine Vaginal Epithelial Cells

1999 ◽  
Vol 67 (8) ◽  
pp. 3847-3854 ◽  
Author(s):  
B. N. Singh ◽  
J. J. Lucas ◽  
D. H. Beach ◽  
S. T. Shin ◽  
R. O. Gilbert
Keyword(s):  
Epithelial Cells ◽  
Cell Surface ◽  
Trichomonas Vaginalis ◽  
Host Cells ◽  
Tritrichomonas Foetus ◽  
Trypan Blue Exclusion ◽  
Vaginal Epithelial Cells ◽  
Host Parasite

ABSTRACT An in vitro culture system of bovine vaginal epithelial cells (BVECs) was developed to study the cytopathogenic effects ofTritrichomonas foetus and the role of lipophosphoglycan (LPG)-like cell surface glycoconjugates in adhesion of parasites to host cells. Exposure of BVEC monolayers to T. foetusresulted in extensive damage of monolayers. Host cell disruption was measured quantitatively by a trypan blue exclusion assay and by release of 3H from [3H]thymidine-labeled host cells. Results indicated contact-dependent cytotoxicity of host cells byT. foetus. The cytopathogenic effect was a function ofT. foetus density. Metronidazole- or periodate-treatedT. foetus showed no damage to BVEC monolayers. A related human trichomonad, Trichomonas vaginalis, showed no cytotoxic effects, indicating species-specific host-parasite interactions. A direct binding assay was developed and used to investigate the role of a major cell surface LPG-like molecule in host-parasite adhesion. The results of competition experiments showed that the binding to BVECs was displaceable, was saturable, and yielded a typical binding curve, suggesting that specific receptor-ligand interactions mediate the attachment of T. foetus to BVECs. Progesterone-treated BVECs showed enhanced parasite binding. T. foetus LPG inhibited the binding of T. foetus to BVECs; the LPG from T. vaginalis and a variety of other glycoconjugates did not. These data imply specificity of LPG on host-parasite adhesion. Periodate-treated parasites showed no adherence to host cells, indicating the involvement of carbohydrate containing molecules in the adhesion process.

A new technique for manipulating host–parasite interactions by low speed centrifugation

1978 ◽  
Vol 56 (5) ◽  
pp. 542-545 ◽  
Author(s):  
Margaret A. Waterman ◽  
James R. Aist ◽  
Herbert W. Israel
Keyword(s):  
Host Response ◽  
Host Cells ◽  
Plant Tissues ◽  
Powdery Mildew Fungus ◽  
Host Cytoplasm ◽  
Erysiphe Graminis Hordei ◽  
Host Parasite Interactions ◽  
Simultaneous Comparisons ◽  
A New Technique ◽  
Host Parasite

An apparatus and a method for centrifuging living, inoculated plant tissues were developed for studies of a cytoplasm-related host response of barley coleoptiles to penetration by the powdery mildew fungus Erysiphe graminis hordei. When the coleoptiles were attached to the apparatus with the long axes of the cells parallel to the centrifugal force, cytoplasm-rich and cytoplasm-poor zones were produced, permitting simultaneous comparisons of interactions in the presence or absence of host cytoplasm. The inner epidermis was inoculated and centrifuged for 12–14 h at 4750 × g. Desiccation was prevented by addition of liquids at the cut end of each coleoptile; the rest of the coleoptile was dry and suitable for inoculation with E. graminis conidia. Of the host cells, 50–80% had well-compacted cytoplasm, conidia developed penetration and infection structures, and the host response was restricted to cytoplasm-rich zones and was shown to be cytoplasm-dependent. Cytoplasmic streaming resumed within 10 min after centrifugation stopped, and 90–100% of the epidermal cells were actively streaming 3 h later. This centrifugation method could be adapted and applied to studies of the other host–parasite interactions.

scholarly journals Biochemical Characterization and Functional Studies of Acanthamoeba Mannose-Binding Protein

2005 ◽  
Vol 73 (9) ◽  
pp. 5775-5781 ◽  
Author(s):  
Marco Garate ◽  
Ibis Cubillos ◽  
Jeffrey Marchant ◽  
Noorjahan Panjwani
Keyword(s):  
Target Cell ◽  
Biochemical Characterization ◽  
Binding Protein ◽  
Host Cells ◽  
Neutral Sugar ◽  
Host Parasite Interactions ◽  
Mannose Binding Protein ◽  
Mannose Binding ◽  
Virulence Protein ◽  
Host Parasite

ABSTRACT Acanthamoebae produce a painful, sight-threatening corneal infection. The adhesion of parasites to the host cells is a critical first step in the pathogenesis of infection. Subsequent to adhesion, the parasites produce a potent cytopathic effect (CPE) leading to target cell death. Recent studies showing that acanthamoebae express a mannose-binding protein (MBP) and that free α-mannose (α-Man) specifically inhibits the adhesion of parasites to host cells suggest that the MBP plays a key role in the pathogenesis of Acanthamoeba infection by mediating host-parasite interactions. However, direct evidence showing that Acanthamoeba MBP is a virulence protein has been lacking. In this study, we demonstrate that the polyclonal immunoglobulin Y (IgY) antibodies prepared against affinity-purified Acanthamoeba MBP markedly inhibit the adhesion of parasites to host cells. The antibody also inhibited the Acanthamoeba-induced CPE on host cells. In contrast, preimmune IgY did not influence either the adhesion of the parasites to host cells or the amoeba-induced CPE. Using a variety of approaches, including affinity chromatography on an α-Man gel, electrophoresis under native and denaturing conditions, biotinylation of cell surface proteins, and immunostaining, it was conclusively established that Acanthamoeba MBP is located on the surface membranes of the parasites. Neutral-sugar analysis and lectin binding experiments using succinylated concanavalin A, a plant lectin with high affinity for mannose, revealed that Acanthamoeba MBP is itself a mannose-containing glycoprotein. N-Glycanase treatment to remove N-linked oligosaccharides shifted the subunit molecular mass of MBP from 130 kDa to 110 kDa. Hexosamine analysis revealed that Acanthamoeba MBP lacks detectable levels of GalNAc, suggesting the absence of O-linked oligosaccharides. In summary, we have characterized Acanthamoeba MBP and have shown that it is a major virulence protein responsible for host-parasite interactions and the parasite-induced target cell destruction.

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