Abstract:
:Intraerythrocytic malaria parasites ingest the cytosol of their host cell and digest it inside their acid food vacuoles. Acidified (pH 4-5.5, 37 degrees C) human red blood cell lysates were used to simulate this process, measuring the denaturation of haemoglobin (Hb) and the release of iron, in the absence or presence of exogenous protease. Spontaneous Hb denaturation and appearance of non-heme iron were observed upon lysate acidification, their rates decreasing with increasing pH, and increasing in the presence of protease. Both processes were inhibited by the quinoline-containing anti-malarial drugs (QCDs) chloroquine, quinine, mefloquine and amodiaquine at concentrations well below those expected in the acidic food vacuole of the parasite. Spectrophotometric analysis indicated that chloroquine complexes with heme in acid-denatured haemoglobin. Other weak bases as well as verapamil and diltiazem, known to reverse the resistance of malarial parasites to chloroquine, were without effect indicating that the action of QCDs is specific. Based on our previous results and the present report, we suggest that iron release in acidified lysates is mediated through the formation of ferryl (Fe(IV)) radicals. QCDs possibly complex with this radical, as they do with heme, and prevent its contact with an adjacent heme molecule which is required for ring opening and iron release. These results may suggest that one of the anti-malarial effects of QCDs is to deprive the parasite of an adequate iron supply. Addition of iron to cultures of Plasmodium falciparum was expected to circumvent the deprivation of iron and reduce the anti-malarial effect of QCDs. However, adding iron as penetrating fructose or nitrilotriacetate complexes did not alter the parasite's susceptibility to chloroquine. Ascorbate markedly increased the release of iron in acidified lysates, and this effect was not reduced by chloroquine. Ascorbate was found to decrease parasite susceptibility to chloroquine, suggesting that iron deprivation may be an important factor in the anti-malarial action of QCDs.
journal_name
Parasitologyjournal_title
Parasitologyauthors
Gabay T,Krugliak M,Shalmiev G,Ginsburg Hdoi
10.1017/s0031182000075910subject
Has Abstractpub_date
1994-05-01 00:00:00pages
371-81eissn
0031-1820issn
1469-8161journal_volume
108 ( Pt 4)pub_type
杂志文章相关文献
PARASITOLOGY文献大全abstract::Monoclonal antibodies reacting with pellicular antigens of Toxoplasma gondii tachyzoites have been selected among hybridomas produced against this organism by immunofluorescence assay. These antigens have been further characterized by immunofluorescence on living zoites, Western immunoblotting and immunoprecipitation ...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/s0031182000066695
更新日期:1988-08-01 00:00:00
abstract::Sex ratio theory posits that the adaptive proportion of male to female gametocytes of a malaria parasite within the vertebrate host depends on the degree of inbreeding within the vector. Gametocyte sex ratio could be phenotypically flexible, being altered based on the infection's clonal diversity, and thus likely inbr...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/s0031182003004207
更新日期:2004-01-01 00:00:00
abstract::Kudoid parasites are significant pathogens of marine fish. In the past, specific identification has been difficult due to a paucity of detailed morphological and biological information provided in the original description of some species. However, the introduction of DNA analysis has dramatically improved diagnosis. F...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S0031182009991557
更新日期:2010-04-01 00:00:00
abstract::Oligosaccharides are broadly present on Leishmania cell surfaces. They can be useful for the leishmaniases diagnosis and also helpful in identifying new cell markers for the disease. The disaccharide Galα1-3Galβ is the immunodominant saccharide in Leishmania cell surface and is the unique non-reducing terminal glycosp...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S0031182018000720
更新日期:2018-12-01 00:00:00
abstract::Sequence comparisons have recently shown that the Schistosoma mansoni protein Sm32 is similar to asparaginyl endoproteinases, a novel family of cysteine proteinases, of which the legumains from legumes are the best characterized. By synthesizing and employing fluorogenic peptide substrates for the specific detection o...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/s0031182000077052
更新日期:1995-12-01 00:00:00
abstract::We present a new phylogenetic analysis of 15 primate Plasmodium species based on 18S rDNA sequences including new sequences of Plasmodium coatneyi, P. fieldi, P. gonderi, P. hylobati and P. simium. The results are discussed in the context of the parasite host species and their geographical distribution. Contrary to ot...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/s0031182004006146
更新日期:2004-12-01 00:00:00
abstract::Humans and other hosts acquire Toxoplasma gondii infection by ingesting tissue cysts in undercooked meat, or by food or drink contaminated with oocysts. Currently, there is no vaccine to prevent clinical disease due this parasite in humans, although, various T. gondii vaccine candidates are being developed. Mice are g...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S0031182011001673
更新日期:2012-01-01 00:00:00
abstract::Life-cycle stages of the microsporidia Nosema bombycis, the pathogen causing silkworm pebrine, were separated and purified by an improved method of Percoll-gradient centrifugation. Soluble protein fractions of late sporoblasts (spore precursor cells) and mature spores were analysed by two-dimensional polyacrylamide ge...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S0031182011000801
更新日期:2011-08-01 00:00:00
abstract::Between December 2007 and March 2009, small mammals were captured in 6 Atlantic Forest patches in Brazil. We assessed tick-host associations and whether they differ among forest strata, sites, seasons, and host age classes or between sexes. Moreover, we assessed the exposure of animals to Rickettsia spp. In total, 432...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S0031182011001740
更新日期:2012-01-01 00:00:00
abstract::Human strongyloidiasis is a serious disease mostly attributable to Strongyloides stercoralis and to a lesser extent Strongyloides fuelleborni, a parasite mainly of non-human primates. The role of animals as reservoirs of human-infecting Strongyloides is ill-defined, and whether dogs are a source of human infection is ...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S0031182020000979
更新日期:2020-09-01 00:00:00
abstract::Oesophagostomum dentatum stages were investigated for glutathione S-transferase (GST) expression at the protein and mRNA levels. GST activity was detected in all stages (infectious and parasitic stages including third- and fourth-stage larvae of different ages as well as males and females) and could be dose-dependentl...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S0031182008004769
更新日期:2008-09-01 00:00:00
abstract::In the context of a broader program dealing with the symbiotic associations of apple snails, we sampled three species that coexist in Lake Regatas (Palermo, Buenos Aires, Argentina). The population of Asolene platae, (but not those of Pomacea canaliculata and Pomacea scalaris) showed trematode larvae (echinocercariae ...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S0031182019000027
更新日期:2019-06-01 00:00:00
abstract::The occurrence of multiple-clone Plasmodium falciparum haploid blood-stage infections is a pre-requisite for cross-fertilization and genetic exchange at the diploid stage in the mosquito. Using monoclonal antibodies against 3 polymorphic blood-stage antigens, a method of two-colour differential immunofluorescence allo...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/s0031182000059217
更新日期:1991-08-01 00:00:00
abstract::The surface proteins and glycoproteins of red cells from Plasmodium berghei-infected blood have been radio-isotope labelled and compared with those of normal mouse erythrocytes using the following protein labelling probes: lactoperoxidase-catalysed radio-iodination of tyrosyl residues, periodate oxidation and NaB3H4 r...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/s0031182000056031
更新日期:1980-10-01 00:00:00
abstract::Quinine (QN) and quinidine (QND) have been commonly used as effective and affordable antimalarials for over many years. Quinine primarily is used for severe malaria treatment. However, plasmodia resistance to these drugs and poor patient compliance limits their administration to the patients. The declining sensitivity...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S003118201200176X
更新日期:2013-03-01 00:00:00
abstract::In South America, visceral leishmaniasis is frequently caused by Leishmania infantum and, at an unknown frequency, by Leishmania amazonensis. Therefore, mixed infections with these organisms are possible. Mixed infections might affect the clinical course, immune response, diagnosis, treatment and epidemiology of the d...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S0031182017000464
更新日期:2017-08-01 00:00:00
abstract::Expression of metalloprotease activities during metacyclogenesis of a series of strains and clones of Trypanosoma cruzi was investigated using SDS-polyacrylamide gel electrophoresis with a range of different co-polymerized proteolytic substrates. A complex pattern of metalloprotease expression, with considerable quant...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/s0031182000066622
更新日期:1996-04-01 00:00:00
abstract::Ultrastructural investigations (SEM, TEM) combined with lectin-binding analysis, have revealed concurrent modifications in tegumentary structure and surface glycoconjugates during the establishment and differentiation of Echinococcus multilocularis metacestodes in jirds. The laminated layer, which is amorphous and ric...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/s003118200006087x
更新日期:1992-02-01 00:00:00
abstract::The effects of the phenothiazine, Stelazine, on Hymenolepis diminuta were investigated. The cestode was incubated for 10 min at 37 degrees C with 1 mM trifluoperazine, in the presence and absence of Ca2+. Assay of brush border enzymes showed that drug treatment lowered the activities of alkaline phosphatase, Ca2+-ATP'...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/s003118200005352x
更新日期:1987-02-01 00:00:00
abstract::Pinewood nematode, Bursaphelenchus xylophilus, a pine parasitic nematode, poses a serious threat to its host pine forests globally. When dispersal-stage larvae 4 (dauer, DL4) of B. xylophilus enters the new pine, it moults into propagative adult (dauer recovery) and reproduces quickly to kill the host pine. Here, we f...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S0031182019001264
更新日期:2020-01-01 00:00:00
abstract::Sodium fluoride (NaF) is an anion that has been previously shown to block the moulting process of Ascaris suum larvae. This study describes moulting and development-specific protein expression profiles of A. suum lung-stage L3 (AsLL3) following NaF exposure. AsLL3s cultured in the presence or absence of NaF were prepa...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S0031182006000576
更新日期:2006-10-01 00:00:00
abstract::In situations where malaria eradication is not an option in the foreseeable future the emphasis must be on the control of morbidity and mortality due to malaria. Under such circumstances drawing a distinction between malarial parasitization and malarial disease may be important for workers in both field and laboratory...
journal_title:Parasitology
pub_type: 杂志文章,评审
doi:10.1017/s0031182000075247
更新日期:1992-01-01 00:00:00
abstract::In recent years, a malaria infection of humans in South East Asia, originally diagnosed as a known human-infecting species, Plasmodium malariae, has been identified as a simian parasite, Plasmodium knowlesi. This species had been subject to considerable investigation in monkeys since the 1930s. With the development of...
journal_title:Parasitology
pub_type: 历史文章,杂志文章,评审
doi:10.1017/S0031182016001888
更新日期:2018-01-01 00:00:00
abstract::The development of drug resistance by the present Houghton strain of Eimeria tenella to the quinolones, methyl benzoquate and buquinolate, was found to take place after a single experimental passage. The development of resistance was independent of drug selection pressure and showed cross resistance to other quinolone...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/s0031182000053130
更新日期:1975-08-01 00:00:00
abstract::As more facts emerge regarding the ways in which E. multilocularis-derived molecules trigger the host immune response and modulate the host-parasite interplay, it becomes possible to envisage how the parasite can survive and proliferate in its intermediate host, while in other hosts it dies out. Through effects on cel...
journal_title:Parasitology
pub_type: 杂志文章,评审
doi:10.1017/S0031182009991533
更新日期:2010-03-01 00:00:00
abstract::Neospora caninum causes economical impact in cattle-raising farms since it is implicated as the major cause of bovine abortions. Although infection by the parasite has been widely described in mammals, the role of birds in its life-cycle is still obscure. Therefore, this work aimed to evaluate the infection by N. cani...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S0031182007003344
更新日期:2007-12-01 00:00:00
abstract::Cercariae of the bird schistosome Trichobilharzia regenti and of the human schistosome Schistosoma mansoni employ proteases to invade the skin of their definitive hosts. To investigate whether a similar proteolytic mechanism is used by both species, cercarial extracts of T. regenti and S. mansoni were biochemically ch...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/S0031182007002910
更新日期:2007-10-01 00:00:00
abstract::Artificially transformed schistosomula of Schistosoma mansoni develop a consistent but small protection against the lethal effects of antibody plus complement when cultured for 24 h in a chemically defined medium. In contrast, they become rapidly resistant to antibody plus complement, when cultured in the presence of ...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/s0031182000049404
更新日期:1978-10-01 00:00:00
abstract::Experiments to investigate the metabolism of glycine, L-glutamic acid and L-aspartic acid by Moniliformis moniliformis were carried out by incubating adult worms aerobically for 3 h at 37 degrees C in Tyrode's solution containing either [U-14C]glycine, L-[U-14C]glutamic acid, L-[U-14C]aspartic acid or L-[4-14C]asparti...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/s0031182000055876
更新日期:1987-06-01 00:00:00
abstract::Trypanosoma evansi and Trypanosoma vivax are the most extensively distributed trypanosomes responsible for diseases in livestock. Western blot and indirect immunofluorescence assays revealed a high immunological cross-reaction between these two parasites. An antigen with an apparent molecular mass of 64 kDa (p64), whi...
journal_title:Parasitology
pub_type: 杂志文章
doi:10.1017/s0031182001001214
更新日期:2002-03-01 00:00:00