bluuebunny/crossref_metadata_2025_split huggingface dataset:
During canine viscero-cutaneous leishmaniasis the anti-Hsp70 antibodies are specifically elicited by the parasite protein
Authors: Quijada L. , Requena J. M. , Soto M. , Alonso C. 
Published: June 2009

SUMMARYALeishmania infantumcDNA library was screened with sera from dogs with viscero-cutaneous leishmaniasis. Sequence analysis of a positive clone isolated from the library revealed that it coded for the carboxyl-terminal region of a member of the 70-kDa heat-shock protein family. The full-length sequence of theL. infantumhsp70 gene was determined after isolation of genomic clones. This protein shows a high degree of sequence conservation with the homologous protein from other organisms. To test its antigenicity a recombinant Hsp70 protein fused to the maltose-binding protein was produced inEscherichia coliusing the expression vector pMAL-cRI. By FAST-ELISA assays it was observed that while the complete recombinant protein was recognized by 100% of the sera, the 20 carboxyl-terminal amino acids of the protein were only recognized by 30% of those sera. Thus, although a B-cell epitope must be present within the carboxyl terminal end of the protein other antigenic determinant(s) must reside out of this region. The analysis of the cross-reactivity with mouse Hsp70 by Western blotting strongly suggests that the anti-Hsp70 antibodies generated by infection withL. infantumare directed at specific determinants of theL. infantumHsp70. Thus, our results indicate that anti-Hsp70 autoantibodies are not induced duringLeishmaniainfection.
Neutral glycolipids ofSchistosoma mansonias feasible antigens in the detection of schistosomiasis
Authors: Dennis R. D. , Baumeister S. , Lauer G. , Richter R. , Geyer E. 
Published: June 2009

SUMMARYThe neutral glycolipid fraction from mouse-propagated,Schistosoma mansoniadult worms has been investigated as to its chromatographic and antigenic properties, and whether it fulfills the serodiagnostic antigen requirements of sensitivity and specificity in the detection of schistosomiasis. Serological analyses were performed by thin-layer chromatography immunostaining and ELISA. In the acute-phase form of mouse schistosomiasis, the kinetics of development of neutral glycolipid-specific antibody levels was correlated with the intensity of the initial infection and the response was dominated by IgG, as represented by the subclass IgG1. With the experimental animal helminthiases screened, glycolipid antigenicity fulfilled the fundamental traits for a serodiagnostic reagent. In the chronic-phase form of human schistosomiasis mansoni, neutral glycolipid-specific antibody levels were not correlated with the intensity of infection, as estimated from the faecal content of parasite eggs, whilst the isotypic response was dominated by IgM and IgG, the latter represented primarily by IgG1 and secondarily by IgG3. With other human helminthiases, glycolipid antigenicity was incomplete, in that, the specificity was only partially fulfilled. The reason for this incomplete specificity has been clarified, in part, by the detection of cryptic schistosomiasis infections in the cohorts of African patient sera examined.
AGiardia duodenalisgene encoding a protein with multiple repeats of a toxin homologue
Authors: Chen N. , Upcrofta J. A. , Upcroft P. 
Published: June 2009

SUMMARYA gene,CRP136,from the intestinal protozoan parasiteGiardia duodenalis,expressed at a high level in a metronidazole-resistant line, encodes a 136 kDa protein with 23 copies of a 40 amino acid repeat. The protein is cysteine-rich and has the typical membrane-spanning region and CXXC amino acid motifs of a family ofGiardiacysteine-rich surface proteins (CRSPs). The repeat unit inCRP136, shares 57% homology with the gene encoding the precursor of the sarafotoxins, a group of snake toxins from the burrowing adder known to cause symptoms similar to those of humans acutely infected withGiardia.The sarafotoxins are low molecular weight sulphydryl cross-linked peptides which are proteolytically cleaved from a precursor polyprotein.CRP136has homology over the entire length of the sarafotoxin precursor, and the repeats are of the same length. ThusCRP136represents the first evidence for a potentialGiardiatoxin. The genomic copy number ofCRP136appears to be the same in both the parent and drug-resistant lines and expression of this gene, and at least one other, is associated with a conserved partial duplication, but not amplification, of one chromosome.
Transcriptional regulation of Schistosoma mansoni calreticulin: possible role of AP-1
Authors: Khalife J. , Godin C. , Capron A. 
Published: June 2009

SUMMARYLittle is known about the regulation and control of Schistosoma mansoni gene expression. In order to study such mechanisms a gene reporter expression vector construction, under the control of a promoter region derived from the S. mansoni calreticulin gene was used to transfect the human Jurkat T cell line. The promoter region contains potential TATA and CAAT boxes as well as an AP-1 core element. We show here that transcriptional factors of eucaryotic cells may induce a gene reporter activity under the control of a S. mansoni promoter region. Treatment of stably transfected cells with N-acetyl cysteine (NAC), a well-characterized antioxidant which counteracts the effects of reactive oxygen intermediates, enhanced the AP-1 dependent transactivation. This effect was abolished when the SmCaR promoter region was deleted in the AP-1 site. Electrophoretic Mobility Shift Assays showed that the AP-1 sequence of S. mansoni bound to both S. mansoni extracts and in nuclear extracts from Jurkat cells, thus explaining possible activation of AP-1 by NAC. Finally treatment of S. mansoni schistosomula and adult worms with NAC induced an increased synthesis of calreticulin protein suggesting a possible role of redox mechanisms in the regulation of a calreticulin gene transcription process in S. mansoni.
Computer model of the maintenance and selection of genetic heterogeneity in polygamous helminths
Authors: Saul A. 
Published: June 2009

SUMMARYA stochastic simulation model of the transmission and maintenance of genetic heterogeneity in the absence and presence of external selection pressures is presented for polygamous intestinal helminths such as Ascaris. The model assumes that the density distribution of the adult parasites is highly aggregated and that density-dependent effects on fecundity are important. The model gives rise to stable infection rates in the host. Where the parasite population contains genetic heterogeneity, with the exception of stochastic fluctuations which models genetic drift, the ratio of the different alleles remained constant over extended periods of time. This result contrasts with that of an earlier analytical model (Anderson, R. M., May, M. R. & Gutpa S. (1989) Parasitology 99, S59–S79), in which uneven mating probabilities for the different combinations of worm possible in a host was postulated to inevitably lead to fixation of the most abundant allele. New results suggest that in spite of the restricted choice of mating available to a worm in the confines of a host, selection pressure always leads to enrichment of the parasites carrying resistant alleles.
Resistance of glucose-6-phosphate dehydrogenase deficiency to malaria: effects of fava bean hydroxypyrimidine glucosides onPlasmodium falciparumgrowth in culture and on the phagocytosis of infected cells
Authors: Ginsburg H. , Atamna H. , Shalmiev G. , Kanaani J. , Krugliak M. 
Published: June 2009

SUMMARYThe balanced polymorphism of glucose-6-phosphate dehydrogenase deficiency (G6PD-) is believed to have evolved through the selective pressure of malaria combined with consumption of fava beans. The implicated fava bean constituents are the hydroxypyrimidine glucosides vicine and convicine, which upon hydrolysis of their β-O-glucosidic bond, become potent pro-oxidants. In this work we show that the glucosides inhibit the growth ofPlasmodium falciparum, increase the hexose-monophosphate shunt activity and the phagocytosis of malaria-infected erythrocytes. These activities are exacerbated in the presence of β-glucosidase, implicating their pro-oxidant aglycones in the toxic effect, and are more pronounced in infected G6PD-erythrocytes. These results suggest that G6PD-infected erythrocytes are more susceptible to phagocytic cells, and that fava bean pro-oxidants are more efficiently suppressing parasite propagation in G6PD-erythrocytes, either by directly affecting parasite growth, or by means of enhanced phagocytic elimination of infected cells. The present findings could account for the relative resistance of G6PD-bearers to falciparum malaria, and establish a link between dietary habits and malaria in the selection of the G6PD-genotype.
Immunodominance, competition and evolution in immunological responses to helminth parasite antigens
Authors: Austin D. J. , Anderson R. M. 
Published: June 2009

SUMMARYThe paper describes the development and analysis of a mathematical framework for the study of the within-host population dynamics of the interaction between macroparasites and the human immune system. Simple models of this interaction based on the proliferation of T cell clones specific to parasite antigen, and the impact of clonal expansion on parasite survival, capture the basic features of age-related changes in worm loads within human communities. The model is generalized to multiple epitopes on a single antigen, and reveals competitive exclusion amongst T cells, with a single clone becoming immunodominant in the absence of cross-reactive responses and genetic variation. The introduction of genetic heterogeneity and concomitant variability in the immunogenicity of specific epitopes induces additional complexity into the dynamical interaction. Most importantly, multiple epitope models with antigenic variation suggest that the immunodominant response may not necessarily be targeted at the epitope at which some strains show the greatest immunogenicity. High immunogenicity at a particular epitope can be masked by genetic variability even though many of the variants are more immunogenic at this epitope by comparison with the epitope to which the immunodominant immunological response is directed.
Experimental Schistosoma bovis infection in goats. Circulating antigen and antibody responses to egg and adult worm antigens during infection and following treatment with praziquantel
Authors: Johansen M. V. , Fillié Y. , Monrad J. , Christensen N. Ø. , Deelder A. 
Published: June 2009

SUMMARYCirculating antigen levels and antibody responses in Schistosoma bovis-infected West African Dwarf goats were evaluated during infection and following treatment with praziquantel (60 mg/kg) 13 weeks post-infection. One day, 1 week and 4 weeks post-treatment, subgroups of goats were sacrificed and perfused for worm recovery. For comparison, parasite-free control animals were included. Blood and faecal samples were collected biweekly. Two gut-associated schistosome antigens, circulating cathodic and circulating anodic antigen (CCA and CAA) and 3 specific antibody responses (total Ig, IgG and IgM) were measured. For specific antibody detection, crude S. bovis adult worm and egg homogenates were used. The level of CCA in the infected groups was significantly elevated from the time of onset of egg excretion onwards. However, following treatment, the CCA litres dropped to control levels within 1 week post-treatment. Strong positive correlations were found between CCA levels and worm counts and faecal egg counts during peak egg excretion. The correlations of CAA and specific antibody litres to egg and worm counts were poor. The antibody responses were all significantly elevated in the infected goats during patency, but only marginally affected by the treatment. Hence, CCA proved to be superior by correlating strongly to the level of infection and by being a sensitive indicator of the effect of treatment.
Light microscope observations of granulomatous reactions against developing Porocephalus crotali (Pentastomida: Porocephalida) in mouse and rat
Authors: Ambrose N. C. , Riley J. 
Published: June 2009

SUMMARYThe development of granulomatous reactions against moulting nymphal pentastomids (Porocephalus crotali) in the tissues of rat and mouse intermediate hosts is described. Adipose tissue and lungs are favoured sites for encystment accounting for 70% of larvae. Six moults separate the primary larva from the final infective stage which first appears about 80 days post-infection (p.i.) and is fully infective by day 120. Larvae, and particularly their cast cuticles, are the foci of granulomatous reactions characterized by an intense eosinophilia. During ecdysis, large numbers of eosinophils permeate the entire lesion but, significantly, degranulation is limited to the underside of cast cuticles where the resultant debris is endocytosed by macrophage/epithelioid cells. A pronounced asymmetry in the granulomatous lesion, evident even in the earliest cysts, results from the accumulation of individual epithelioid granulomas associated with cuticle fragments close to the ventral side of the developing parasite; each is circumscribed by fibrosis. External to this region are extensive tracts of tissue composed of mature plasma cells. Particularly in rats, large numbers of partially degranulated mast cells ( = globule leucocytes) also surround cuticle granulomas, and mast cell granules can accumulate within macrophages and fibroblasts. Inflammation slowly subsides once the infective stage is attained. This 1 cm-long larva resides in a thin, fibrotic, C-shaped cyst and can remain viable for years: uniquely this instar retains its last moulted cuticle as a protective sheath. Nymphal instars II-VI feed predominantly upon eosinophils but we do not yet know whether this requirement is obligate.
Environmental influences on egg production by the monogenean Protopolystoma xenopodis
Authors: Jackson Helen C. , Tinsley R. C. 
Published: June 2009

SUMMARYA continuous succession of egg capsules is formed in the ootype of Protopolystoma xenopodis and released into the urinary bladder of the host, Xenopus laevis. Since egg capsules are passed out with the aquatic toad's urine several times a day, the rate of parasite egg production can be recorded accurately by direct counts. Temperature has a marked influence on the rate of egg output which doubles in response to a rise from 17 to 25 °C. Under constant temperature conditions regular egg collections from isolated toads infested with single Protopolystoma revealed that rates of production remain stable for periods of several weeks. The overall mean rate of egg production was 8·9 eggs/worm/day (e.w.d.) at 20·0±0·5 °C (based on 5 consecutive egg collections from 58 individual parasites). Significant differences were observed, however, between the mean rates of output from different hosts, ranging from 2·1 e.w.d. (s.d. = 0·6) to 17·7 e.w.d. (S.D. = 3·2). Neither differences in worm age nor host-factors could explain the observed range in output. Worms transferred to new hosts resumed egg production at pre-transfer rates, suggesting inherent differences in the capacity for egg production by individual parasites. Total production increased with increasing worm burden, but output per parasite was significantly reduced in groups of 2, 3 or 4. Whilst competition for some finite resource provides one interpretation, this observation could equally reflect a statistical phenomenon associated with the reduced chance of encountering groups of individuals which are heterogeneous for egg production as worm burden increases and sample size decreases.
Coelotrophus nudus gen. et sp.nov., an endoparasitic copepod causing sterility in a sipunculan Phascolosoma scolops (Selenka and De Man) from Sado Island, Japan
Authors: Ho Ju-Shey , Katsumi Fumimasa , Honma Yoshiharu 
Published: June 2009

SUMMARYA new form of parasitic copepod, Coelotrophus nudus gen. et sp. nov., is described based on the specimens recovered from the coelomic cavity of a species of Sipuncula, Phascolosoma scolops (Selenka and Be Man), at Sado Island in the Sea of Japan. The new genus is distinguishable from its closest allies, Akessonia, Siphonobius and Staurosoma, in the complete absence of appendages in the female and the absence of a mouth in both female and male. The incidence of infection is fairly high (34·1%) in this population of P. scolops at Sado Island. Histological studies of the gonads and microscopical examinations of the coelomic fluid of P. scolops collected monthly from April through December, 1979 have revealed that the presence of C. nudus causes sterility in its host. Some infected P. scolops also showed a marked decrease in the number of corpuscles in the coelomic fluid.
Differentiation of major genotypes ofGiardia intestinalisby polymerase chain reaction analysis of a gene encoding a trophozoite surface antigen
Authors: Ey P. L. , Andrews R. H. , Mayrhofer G. 
Published: June 2009

SUMMARYThe polymerase chain reaction (PCR) has been used to amplifyin vitroa semi-conserved region of a gene encoding anMr68–72000 surface antigen ofGiardia intestinalistrophozoites. Using primers specific for conserved nucleotide sequences identified within the promoter-distal portion of two homologous genes (tsp11 andtsa417) cloned previously from theG. intestinalisisolates Ad-1 (from Australia) and WB (from Afghanistan), a single PCR-amplified DNA fragment of the expected size (0·52 kilobases) was obtained in high yield from either purified DNA or whole trophozoites of the Ad-1 isolate and from every 1 of 9 other axenicG. intestinalisisolates belonging to genetic groups I and II (defined previously on the basis of allozyme electrophoresis data—Andrewset al.1989). Discernible product was recovered from as few as 2–4 trophozoites. In contrast, 6G. intestinalisisolates that were assigned by allozymic analysis to genetic groups III/IV yielded small amounts of a 0·37-kilobase (kb) amplification product (with evidence in some samples of an additional 0·4 or 0·18 kb fragment) but no 0·52 kb product. Two animal-derived isolates ofG. duodenalis(one from an Australian native rodent,Notomys alexis, the other from a domestic cat) also yielded a single 0·37 kb PCR-amplified fragment, whereas an isolate from another cat produced a 0·34 kb fragment. No product was recovered fromG. muris, a morphologically distinct species ofGiardia. The results demonstrate that different genotypes ofG. duodenaliscan be distinguished using this assay and that it is diagnostic for isolates belonging to two major clusters (groups I/II and III/IV) ofG. intestinalis. The amplified DNA segment appears to be relatively conserved among group I and group II isolates ofG. intestinalis. A related but clearly distinct sequence seems to be conserved among group III/IV isolates ofG. intestinalisand some isolates ofG. duodenalis.
Stimulation of cell division and DNA replication inPrototheca richardsiby passage through larval amphibian guts
Authors: Beebee T. J. C. , Wong A. L.-C. 
Published: June 2009

SUMMARYPrototheca richardsi, an unpigmented heterotrophic alga, causes growth inhibition in amphibian larvae and has proved refractory to culturein Vitro.P. richardsireplication is dependent on regular passaging through tadpole digestive systems; uptake of thymidine by free-livingProtothecacells and incorporation into DNA are very low by comparison with leucine uptake and incorporation into protein, but DNA synthesis is detectable in cells isolated from tadpole intestines. DNA replication was elicited 6–8 h after ingestion in protothecans fed to tadpoles and subsequently re-isolated from them, providing that the tadpoles were fed subsequent to the ingestion. It appears that passaging through tadpole intestines provides an essential stimulus to maintaining an active cell division cycle inP. richardsi.
Discrimination between six species of Theileria using oligonucleotide probes which detect small subunit ribosomal RNA sequences
Authors: Allsopp B. A. , Baylis H. A. , Allsoppi M. T. E. P. , Cavalier-Smith T. , Bishop R. P. , Carrington D. M. , Sohanpal B. , Spooner P. 
Published: June 2009

SUMMARYThe complete small subunit ribosomal RNA (srRNA) gene of Theileria parva was cloned and sequenced. Two primers were designed which permitted the specific amplification of part of the Theileria srRNA gene from Theileria-infected cell line samples which were predominantly (> 95%) bovine DNA. The sequence of the central (variable) region of the srRNA genes of T. annulata, T. taurotragi, T. mutans and two unidentified parasites referred to as Theileria sp. (buffalo) and Theileria sp. (Marula) were obtained. An alignment of the sequences was generated from which 6 oligonucleotide probes, corresponding to species-specific regions, were designed. These probes were demonstrated to provide unequivocal identification of each of the 6 species either by direct detection of parasite srRNA or by hybridization to amplified parasite srRNA genes. The probes were not able to distinguish buffalo-derived T. parva, the causal agent of Corridor disease, from cattle-derived T. parva, the causal agent of East Coast fever.
Electron microscope study of the blood stages of Plasmodium tropiduri, a lizard malaria parasite
Authors: Scorza J. V. 
Published: June 2009

The study of the ultrastructure of the blood stages of P.tropiduri Aragao & Neiva, 1909 shows close similarities between this species and P.floridense, another lizard malaria parasite. The absence of a rounded structure in the merozoites of P.tropiduri, and their tendency not to project beyond the original area occupied
by the schizont are the ultrastructural characteristics that differentiate the two species.The close relationships of homology between P.tropiduri and the Plasmodium of birds are emphasized, and new evidence on their phylogenetic relationships is offered.P.tropiduri has a mode of ingestion and digestion similar to that of P. elongatum. When the size of the cytostome, the size of the boluses produced by the phagotrophy, and the size of the digestive vacuoles are compared, they are seen to be nearly identical in the two species.The comparative study of the structure of the cytostomes of the merozoites and the trophozoites, and of their relationships with the membranes that limit the parasites, gives new evidence that the external membrane of the trophozoites schizonts, and gametocytes is derived from the host cell.An exflagellatory apparatus is described from the microgametocytes of P.tropiduri, and its relationships with similar structures described from the gametocytes of avian Plasmodium and from Coccidia are discussed.