Abstract:
:Acquisition of iron from lactoferrin and transferrin by a parasitic protozoon Tritrichomonas foetus has been studied in vitro. Specific, time-dependent, and saturable binding of iodinated ligands to the outer membrane of T. foetus at 4 degrees C was demonstrated for 125I-labeled lactoferrin only. About 1.7 x 10(5) binding sites of a single class with Kd approximately equal to 3.6 microM was estimated by means of Scatchard analysis. Internalization of the bound lactoferrin was observed at 37 degrees C. The cell-associated radioactivity after 30 min incubation of the parasite with 125I-lactoferrin at 37 degrees C was about 3.5-fold higher than the amount bound at 4 degrees C. The majority of internalized 125I-lactoferrin was released within 15 min of cell reincubation at 37 degrees C in the presence of a 100-fold excess of nonlabeled lactoferrin. Released lactoferrin displayed unchanged mobility on autoradiography. In contrast to lactoferrin, binding of 125I-transferrin was nonspecific and did not display saturable kinetics. The growth of T. foetus in iron-restricted media was stimulated by both lactoferrin and transferrin. The ability of the cells to remove and accumulate iron from both proteins was therefore examined using 59Fe-saturated lactoferrin and transferrin. It was found that trichomonads acquired a comparable amount of iron from both lactoferrin and transferrin during 60 min incubation at 37 degrees C (495 and 577 pmole Fe/mg of protein, respectively). The pH of the assay medium (PBS) decreased from pH 7.4 to 5.6 after incubation with trichomonads. At this pH, marked release of iron from transferrin (up to 47%) but not from lactoferrin (4%) was determined in cell-free media. These results indicate that T. foetus is able to utilize both lactoferrin and transferrin to cover its iron requirements. However, mechanisms of iron acquisition from these host proteins appear to be different. Specific binding and internalization of lactoferrin suggests the possible involvement of receptor-mediated endocytosis in the acquisition of lactoferrin-bound iron, while retrieval of iron from transferrin may depend on the extracellular release of iron from this ligand.
journal_name
Exp Parasitoljournal_title
Experimental parasitologyauthors
Tachezy J,Kulda J,Bahníková I,Suchan P,Rázga J,Schrével Jdoi
10.1006/expr.1996.0068subject
Has Abstractpub_date
1996-07-01 00:00:00pages
216-28issue
2eissn
0014-4894issn
1090-2449pii
S0014-4894(96)90068-5journal_volume
83pub_type
杂志文章abstract::Certain model inhibitors exerted selective action against the catalytic activity of nuclear DNA topoisomerase II (TOPII) of Leishmania panamensis promastigotes. The second-generation fluoroquinolones enoxacin and ciprofloxacin exhibited extraordinarily high anti-parasite selectivity displaying 582- and 40-fold greater...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2007.02.018
更新日期:2007-08-01 00:00:00
abstract::In order to examine the role of IFN-gamma, TNFRp55 and iNOS in inflammatory reaction during toxoplasmosis, IFN-gamma(-/-), TNFRp55(-/-) and iNOS(-/-) mice were experimentally infected with Toxoplasma gondii ME-49 strain. The organs of the mice were evaluated for histology and immunohistochemistry in detection of tissu...
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doi:10.1016/j.exppara.2009.05.011
更新日期:2009-09-01 00:00:00
abstract::The petroleum ether extract of neem oil and its four fractions separated by column chromatography was diluted at different concentrations with liquid paraffin. The acaricidal bioassay was conducted using a dipping method. The results indicated that the median lethal concentration (LC50) of the petroleum ether extract ...
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更新日期:2012-04-01 00:00:00
abstract::Chagas disease is a tropical and systemic disease caused by the parasite Trypanosoma cruzi. This parasite has been divided into six Discrete Typing Units (DTU's) due to its high genetic diversity. T. cruzi I (TcI) is the most prevalent DTU in Colombia and recently associated to cardiomyopathies. The aim of this study ...
journal_title:Experimental parasitology
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doi:10.1016/j.exppara.2012.09.017
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journal_title:Experimental parasitology
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journal_title:Experimental parasitology
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journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2012.02.027
更新日期:2012-05-01 00:00:00
abstract::In this paper, the lytic activity of two variants of Serratia marcescens against promastigotes of Leishmania braziliensis was studied. In vitro assays showed that S. marcescens variant SM365 lyses L. braziliensis promastigotes, while the variant DB11 did not. Scanning electron microscopy (SEM) revealed that S. marcesc...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2009.03.004
更新日期:2009-06-01 00:00:00
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journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/0014-4894(83)90069-3
更新日期:1983-10-01 00:00:00
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journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2004.11.001
更新日期:2005-01-01 00:00:00
abstract::In the present study, several stimuli were tested to liberate Toxoplasma gondii sporozoites from oocysts. Incubation in Na(2)CO(3)-CO(2) buffer at 40 degrees C with ultrasound, followed by incubation at 40 degrees C with bile or deoxycholic acid, was the only method that resulted in 95% liberation of motile infective ...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2004.03.014
更新日期:2004-05-01 00:00:00
abstract::At least eight protein members of HSP70 and three of the HSP60 families have been identified in Trypanosoma cruzi; of these, five HSP70 isoforms and one HSP60 isoform were respectively induced by a 2-hr heat-shock treatment at 37 degrees C. Immunoelectronmicroscopy of epimastigote, spheromastigote, and metacyclic cell...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1006/expr.1996.0081
更新日期:1996-08-01 00:00:00
abstract::A total of 597 faecal samples were collected from western grey kangaroos (Macropus fuliginosus), Euros (M. robustus), red kangaroos (M. rufus) in Western Australia and Eastern Grey Kangaroos (M. giganteus) from Victoria and screened for the presence of Eimeria by PCR at the 18S ribosomal RNA (rRNA) locus. The overall ...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2012.07.003
更新日期:2012-10-01 00:00:00
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journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/0014-4894(85)90043-8
更新日期:1985-12-01 00:00:00
abstract::Ninety-one Chilean, 15 Bolivian, and 9 Argentinian Trypanosoma cruzi stocks, isolated from various hosts and vectors, were characterized by schizodeme analysis with EcoRI and MspI endonucleases. The three major similar pattern groups that emerged from this sample correlated with results of isoenzyme analysis. This res...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/0014-4894(92)90178-d
更新日期:1992-09-01 00:00:00
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journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/0014-4894(86)90011-1
更新日期:1986-08-01 00:00:00
abstract::Immunity in mice infected with Toxoplasma gondii is dependent upon the ability to generate protective levels of the cytokine IFN-gamma. In this report, we present evidence that the attenuated vaccine strain, ts-4, induces the latter cytokine by both IL-12-dependent and -independent pathways. In contrast, strain ME49 a...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1006/expr.1996.0096
更新日期:1996-11-01 00:00:00
abstract::A Schistosoma mansoni G-protein coupled receptor (SmGPCR) was previously cloned and shown to be activated by the biogenic amine, histamine. Here we report a first investigation of the receptor's subunit organization, tissue distribution and expression levels in different stages of the parasite. A polyclonal antibody w...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2009.01.001
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journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2009.09.017
更新日期:2010-02-01 00:00:00
abstract::The concentration of L-hydroxyproline in the liver of ICR female mice increased rapidly during the 8th to 11th weeks of Schistosoma mansoni infection. Free L-proline concentration began to increase about the 7th week and reached its maximum at the 8th to 9th weeks of the infection, when the granulomatous response to t...
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pub_type: 杂志文章
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更新日期:1991-02-01 00:00:00
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journal_title:Experimental parasitology
pub_type: 杂志文章,评审
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abstract::Purine uptake has been studied in many protozoan parasites in the last few years, and several of the purine transporters have been cloned. In contrast, very little is known about the salvage of preformed pyrimidines by protozoa, and no pyrimidine transporters have been cloned, yet chemotherapy based on pyrimidine nucl...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2006.02.018
更新日期:2006-10-01 00:00:00
abstract::The expression and activity of topoisomerase I (PfTopoI) has been examined during the intraerythrocytic stages of the Plasmodium falciparum life cycle. The promoter is inactive during the early ring stage and becomes active only during the later trophozoite and schizont stages. The PfTOP1 transcript starts to accumula...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1006/expr.1998.4362
更新日期:1999-02-01 00:00:00
abstract::Most of the drugs used for the treatment of trichinellosis show a limited bioavailability and a high degree of resistance. Therefore, this study aimed to characterize the anthelmintic potential activity of nitazoxanide (NTZ) in a rat model of experimental trichinellosis. Animals were divided into three groups; group I...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2016.08.009
更新日期:2016-11-01 00:00:00
abstract::Genetic cross is a powerful tool for studying malaria genes contributing to drug resistance, parasite development, and pathogenesis. Cloning and identification of recombinant progeny (RP) is laborious and expensive, especially when a large proportion of progeny derived from self-fertilization are present in the unclon...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2012.10.011
更新日期:2013-01-01 00:00:00
abstract::Ticks deposit saliva at the site of their attachment to a host in order to inhibit haemostasis, inflammation and innate and adaptive immune responses. The anti-haemostatic properties of tick saliva have been described by many studies, but few show that tick infestations or its anti-haemostatic components exert systemi...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2009.12.013
更新日期:2010-04-01 00:00:00
abstract::This article describes a sensitive, cheap, and easy method for assaying chemotaxic responses of Leishmania promastigotes. A gradient of the substance to be assayed was produced inside a series of commercially available capillary tubes submerged in a promastigote suspension. After an incubation period, the attractivene...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1006/expr.2000.4569
更新日期:2000-11-01 00:00:00
abstract::Entomopathogenic nematode Heterorhabditis bacteriophora Az29 and Az36 isolates with different virulence against Popillia unipuncta and soil survival time were isolated from the Azorean archipelago (Portugal) and used for the study. RAPD analysis revealed a very low-level of genetic diversity (GD(axenic Az36 isolate)(a...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2011.12.001
更新日期:2012-02-01 00:00:00
abstract::EhRabB is an Entamoeba histolytica protein involved in phagocytosis. However, proteins that regulate the EhRabB activity are unknown. Here, we report the identification of a putative G protein-coupled receptor of E. histolytica (EhGPCR-1) that binds to EhRabB. By two-hybrid screening, we found a 372-bp cDNA fragment t...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2005.02.014
更新日期:2005-07-01 00:00:00
abstract::Given that signal sequences between secreted proteins of different species can be interchanged, it is reasonable to expect that both mammalian and yeast signal sequence trapping (SST) systems would secrete Haemonchus contortus proteins with similar efficiency and quality. To determine if H. contortus cDNAs that contai...
journal_title:Experimental parasitology
pub_type: 杂志文章
doi:10.1016/j.exppara.2007.12.017
更新日期:2008-05-01 00:00:00