bluuebunny/crossref_metadata_2025_split huggingface dataset:
Host-parasite relationship between congenitalToxoplasmainfection and mouse brain: role of small vessels
Authors: Sims T. A. , Hay J. 
Published: June 2009

SUMMARYSmall vessels showing inflammatory cell infiltrates were invariably observed in the vicinity of intactToxoplasmatissue cysts within the brains of mice congenitally infected with the protozoan. Lymphocytes were observed in intimate contact with the luminal aspect of the endothelium, penetrating into the thickened basal lamina and in the perivascular area, which also contained macrophages and neutrophilic granulocytes. Rarely, lymphocytes were observed attached to the outer membrane of the host neurone which contained aToxoplasmatissue cyst and within the inflammatory infiltrate associated with a disintegrating cyst. An hypothesis is presented which combines these morphological observations to explain the events associated with tissue cyst associated recrudescence of latentToxoplasmainfection in mouse brain.
Immunocytochemical demonstration of a SALMFamide-like neuropeptide in the nervous system of adult and larval stages of the human blood fluke,Schistosoma mansoni
Authors: Brownlee D. J. A. , Fairweather I. , Johnston C. F. , Thorndyke M. C. , Skuce P. J. 
Published: June 2009

SUMMARYThe localization and distribution of SALMFamide immunoreactivity (IR), SI(GFNSALMFamide), in the nervous system of both the adult and larval stages of the trematodeSchistosoma mansonihas been determined by an indirect immunofluorescent technique in conjunction with confocal scanning laser microscopy (CSLM). Immunostaining was widespread in the nervous system of adult male and femaleS. mansoni. In the central nervous system (CNS), IR was evident in nerve cells and fibres in the anterior ganglia, cerebral commissure and dorsal and ventral nerve cords. In the peripheral nervous system (PNS), IR was apparent in nerve plexuses associated with the subtegmental musculature, oral and ventral suckers, the lining of the gynaecophoric canal, and in fine nerve fibres innervating the dorsal tubercles of the male worm. In the reproductive system of male and female worms, Sl-IR was only observed around the ootype/Mehlis' gland complex in the female. Immunostaining was also evident in the nervous system of both miracidium and cercarial larval stages. A post-embedding, IgG-conjugated colloidal gold immunostaining technique was employed to examine the subcellular distribution of SALMFamide-IR in the CNS ofS. mansoni. Gold labelling of peptide was localized over dense-cored vesicles within nerve cell bodies and fibres constituting the neuropile of the anterior ganglia, cerebral commissure and nerve cords of the CNS. Antigen pre-absorption studies indicated that the results obtained do suggest S1-like immunostaining and not cross-reactivity with other peptides, in particular FMRFamide.
Detection of host DNA sequences including the H-2 locus of the major histocompatibility complex in schistosomes
Authors: Iwamura Y. , Yonekawa H. , Irie Y. 
Published: June 2009

SUMMARYThe mouse type 2Alu(B2) sequence was detected in both DNAs ofSchistosoma mansoniandS. japonicumexcept for the cercarial stage by the polymerase chain reaction (PCR). Using several kinds of mouse STMS (sequence tagged microsatellite site) primer sets, PCR products related to the host were found in the DNAs ofS. mansonias well as ofS. japonicum. Products could be detected only in the DNA ofS. japonicumusing certain STMS primer sets. The fact that no products could be amplified from the DNAs of both parasites when other kinds of STMS primer sets were used suggests unequal incorporation of the host DNA into the schistosomes. Furthermore, the sequence of the N-terminal domain of H-2, the mouse major histocompatibility complex (MHC), was detected in the DNAs fromS. mansonimiracidium, male adult andS. japonicumadults, whereas the sequence of the C2domain of H-2 was found only in the DNAs ofS. japonicumadults. This evidence that host DNA sequences, including the class I MHC, exist heterogeneously in the DNAs of schistosomes might provide an important insight for further understanding of host-parasite immune interactions.
Study on the intramolluscal development of Schistosoma bovis: demonstration of three patterns of sporocystogenesis by daughter sporocysts
Authors: Touassem R. , Théron A. 
Published: June 2009

SUMMARYDaughter sporocysts (SpII) of Schistosoma bovis produced by the mother sporocyst (SpI) can direct their production along three different pathways during intramolluscal development. (i) Direct sporocystogenesis–tertiary sporocysts (SpIII) are directly produced by non-cercariae producing daugher sporocysts (SpIII). (ii) Simultaneous sporocystogenesis and cercariogenesis–SpIII are produced by Spil in which cercariae are being produced. (iii) Sporocystogenesis after cercariogenesis-Spill are produced by SpIl in which cercariae are undergoing degeneration. These mechanisms can be interpreted in terms of demographic strategy leading swiftly to the taking over and optimum exploitation of the host's hiotic capacity.
Echinococcus granulosus infection in mice: host responses during primary and secondary infection
Authors: Riley E. M. , Dixon J. B. , Jenkins P. , Ross O. 
Published: June 2009

SUMMARYThe reaction of Balb/c mice to primary and secondary subcutaneous infection with chinoeoccu.s granulosus protoscoleces (PSC) is described. From 3 to 14 days following primary exposure to PSC, draining lymph nodes increase in weight and there is expansion of T and B lymphocyte populations, enhancement of in vitro lymphocyte transformational responses and production of PSC-specific 1gM and IgE antibodies. Despite the persistence of viable PSC in host tissues, lymphocyte responses decline to pre-infection values over the period 3–8 weeks post-infection. Secondary exposure to PSC immediately induces lympho proliferation, enhancement of transformational responses, production of IgE antibody and encapsulation of PSC by inflammatory cells. Although specific antibody levels remain high until at least 8 weeks after challenge infection, lymphocyte activity begins to decline after 4 days and is profoundly suppressed by 10 days. Parasite viability appears to be significantly reduced in secondary, as opposed to primary, infection and is associated with the accumulation of large numbers of eosinophils, mast cells and macrophages in infected tissues.
Environmental sex determination and density-dependent population regulation in the entomogenous nematodeRomanomermis culicivorax
Authors: Tingley G. A. , Anderson R. M. 
Published: June 2009

SUMMARYEnvironmental sex determination in the mermithid nematodeRomanomermisculicivorax is examined in the context of parasite reproductive success and population regulation. Experimental results show that the sex ratio of the nematode within its mosquito host (Culex quinquefasciatus) is dependent on parasite density. Sex ratios are biased to females at low parasite burdens and to males at high parasite burdens. Low temperature further enhances female-biased ratios. The net effect of density-dependent sex determination on parasite and host population growth is shown to be critically dependent on the frequency distribution of parasite numbers/host. Mermithid parasite distributions within natural host populations show low degrees of aggregation relative to other helminth species. The population regulation of the parasite is examined with respect to environmental sex determination and parasite-induced host mortalities by means of simple mathematical models of the dynamics of parasite transmission via its life-cycle. The significance of regulatory constraints on population growth are discussed in relation to the use of mermithids as biological control agents of insect pests or disease vectors.
Division of Giardia isolates from humans into two genetically distinct assemblages by electrophoretic analysis of enzymes encoded at 27 loci and comparison with Giardia muris
Authors: Mayrhofer G. , Andrews R. H. , Ey P. L. , Chilton N. B. 
Published: June 2009

SUMMARYGiardia that infect humans are known to be heterogeneous but they are assigned currently to a single species, Giardia intestinalis (syn. G. lamblia). The genetic differences that exist within G. intestinalis have not yet been assessed quantitatively and neither have they been compared in magnitude with those that exist between G. intestinalis and species that are morphologically similar (G. duodenalis) or morphologically distinct (e.g. G. muris). In this study, 60 Australian isolates of G. intestinalis were analysed electrophoretically at 27 enzyme loci and compared with G. muris and a feline isolate of G. duodenalis. Isolates of G. intestinalis were distinct genetically from both G. muris (approximately 80% fixed allelic differences) and the feline G. duodenalis isolate (approximately 75% fixed allelic differences). The G. intestinalis isolates were extremely heterogeneous but they fell into 2 major genetic assemblages, separated by fixed allelic differences at approximately 60% of loci examined. The magnitude of the genetic differences between the G. intestinalis assemblages approached the level that distinguished the G. duodenalis isolate from the morphologically distinct G. muris. This raises important questions about the evolutionary relationships of the assemblages with Homo sapiens, the possibility of ancient or contemporary transmission from animal hosts to humans and the biogeographical origins of the two clusters.
Variation in the vector competence of Aedes polynesiensis for Wuchereria bancrofti
Authors: Failloux A.-B. , Raymond M. , Ung A. , Glaziou P. , Martin P. M. V. , Pasteur N. 
Published: June 2009

SUMMARYThe vector competences of 6 geographic strains of Aedes polynesiensis for Wuchereria bancrofti were studied using two types of experimental infections. Experimental infection of laboratory-bred mosquitoes fed on the carriers' forearms with different levels of microfilaraemia showed that microfilariae (mf) uptake was directly proportional to the carrier's mf density and, as mf densities decreased, concentration capacity of Ae. polynesiensis increased. It was also shown that infection has an important effect on mosquito mortality, and that the mortality rate differed among mosquito strains. In infections using artificial feeders, the mf uptake was closely regulated, thus showing differences in the vectorial efficiency of Ae. polynesiensis related to the geographic origin of the mosquito strain. The mosquitoes from the Society archipelago were more efficient intermediate hosts than geographically distant strains when infected with W. bancrofti from an island within the archipelago (Tahiti). Mosquito strains from the Society archipelago developed the highest proportion of infective-stage larvae and exhibited the lowest mortality rate when infected with sympatric Tahitian W. bancrofti.
Cytokine and immunoglobulin subclass responses of rats to infection withEimeria nieschulzi
Authors: Smith N. C. , Ovington K. S. , Deplazes P. , Eckert J. 
Published: June 2009

SUMMARYSIV rats infected with a high dose (50000 oocysts) ofEimeria nieschulzidisplayed clinical symptoms of coccidiosis such as diarrhoea (days 6 and 7 post-primary infection) and weight loss (days 6–8 post-primary infection) and were completely immune to challenge with a similar dose. The ability of rats to produce tumour necrosis factor (TNF)in vivowas enhanced during the period of oocyst excretion in the primary infection but significant production of TNF did not occur after challenge infection. Thus, TNF does not appear to be an important factor in resistance to infection withE. nieschulzibut may play some role in resistance to primary infection and in the pathology associated withE. nieschulziinfection. Parasite-specific serum IgM levels (measured by enzyme-linked immunosorbent assay) were also increased during primary infection but returned to background levels at the end of the patent period and were not affected by challenge infection. In contrast to TNF and IgM, serum concentrations ofE. nieschulzi-specific IgGl, IgG2a, IgG2b, IgG2c and intestinal tissue levels of IgA did not begin to increase until after day 12 post-primary infection, reached peak levels between days 20 and 30 post-primary infection and were slightly increased by challenge infection.
The temperature threshold for development of Elaphostrongylus rangiferi in the intermediate host: an adaptation to winter survival?
Authors: Schjetlein J. , Skorping A. 
Published: June 2009

SUMMARYTo test the hypothesis that the relatively high developmental temperature threshold of the parasitic nematode Elaphostrongylus rangiferi in the intermediate snail host is an adaptation to minimize larval mortality during winter, an experiment was set up in which snails of the species Arianta arbustorum were experimentally infected with the parasite. The snails were divided into 3 groups known to contain 1st, 2nd or 3rd-stage larvae, and incubated at 3 °C for an experimental period of 18 weeks. First-stage larvae showed a significantly higher survival rate within snails than 2nd or 3rd-stage larvae. We also found that snails carrying 1st-stage larvae survived better than snails with other larval stages. It is concluded that if the nematode has started development before the hibernation, this has a real and significant effect on the risk of dying. The high developmental threshold is therefore likely to be an adaptation to reduce the chance of hibernating as developing larvae during long periods of low temperatures.
Proterometra macrostoma(Digenea: Azygiidae): variations in cercarial morphology and physiology
Authors: Riley M. W. , Uglem G. L. 
Published: June 2009

SUMMARYSnails,Elimia semicarinata, infected withProterometra macrostomawere collected monthly in 1990 and 1991 from North Elkhorn Creek near Lexington, Kentucky, and kept on a 12:12 h light–dark cycle for 2 weeks. Cercariae emerging from snails were classified into 8 strains (I–VIII) based on differences in number and distribution of spined and spineless papillae on the tail. Cercariae also had unique patterns of emergence, swimming behaviour and infectivity in 4 species of sunfish. Of 513 infected snails collected in May, 339 had pure infections with the strain frequencies (% of 339): I, 46·6; II, 7·7; III, 12·1; IV, 8·8; V, 0·6; VI, 2·7; VII, 11·8; VIII, 9·7. In the multiple infections, 159 snails shed 2 strains, 14 shed 3, and 1 snail shed 4 strains simultaneously. A comparison of sunfish and parasite populations in Kentucky, Ohio and Michigan indicated that strain frequency inP. macrostomais regulated by the species composition of the sunfish population.
The energetic consequences of parasitism: effects of a developing infection ofTrichostrongylus tenuis(Nematoda) on red grouse (Lagopus lagopus scoticus) energy balance, body weight and condition
Authors: Delahay R. J. , Speakman J. R. , Moss R. 
Published: June 2009

SUMMARYThe timing of the energetic consequences of a developing, single-dose infection ofTrichostrongylus tenuislarvae was investigated in captive red grouseLagopus lagopus scoticus. At 12 days post-infection (p.i.), infected birds had a resting metabolic rate 16% greater than controls and thenceforth lost weight at a faster rate than controls. At 16 days p.i. infected birds consumed 38% less energy and excreted 33% less energy than controls. The estimated total daily energy expenditure and energy expended on activity for infected birds at 16 days p.i. were 36% and 83% lower, respectively, than for controls. Infected birds lost condition from 16 days p.i. onwards. The period of energy imbalance at 12–16 days p.i. coincided with development of late 4th-stage larvae into adult worms and the onset of patency. After this, the effects on energy balance diminished. Synchronous development of previously arrestedT. tenuislarvae in wild birds in spring probably has similar effects to those reported here and places grouse under conditions of energy imbalance. The observed effects on energy balance provide a possible mechanism by which the parasite can reduce fecundity and survival of infected grouse.
Ecological, morphological and genetic characterization of sympatric Haemonchus spp. parasites of domestic ruminants in Mauritania
Authors: Jacquiet P. , Humbert J. F. , Comes A. M. , Cabaret J. , Thiam A. , Cheikh D. 
Published: June 2009

SUMMARYThe 4 species of ruminants (dromedary, zebu cattle, sheep and goat) in arid areas of Mauritania harboured Haemonchus spp. as the most frequent internal parasite. This was a rare situation where the 3 putative species, H. longistipes (dromedary), H. placet (zebu cattle) and H. contortus (sheep and goat) occurred sympatrically. The study was undertaken on hosts slaughtered at the Nouakchott abattoir, on the basis of monthly collection of worms. The environment was very unfavourable to H. placei and unfavourable to H. contortus, as intensity of infection remained low throughout the year, whereas infection in the dromedary was 10 to 20-fold higher. The survival strategies during the long, dry season were different: the surviving stages were either 4th-stage larvae in digesta (dromedaries), 4th-stage larvae either in digesta or mucosae (cattle), or 4th-stage larvae in mucosae and few adults (sheep and goats). The prolificacy of female worms, indicative of the potential to contaminate pastures, was similar for all Haemonchus spp. in the rainy season. H. longistipes behave differently during the pre-rainy season as no increase of prolificacy could be demonstrated as observed in the other species. Traits of vulvar morphology are considered as markers of ecological adaptation and were studied. The knobbed and smooth female morphs (in equal proportions) were the most frequent in H. longistipes, the knobbed morph out-numbered the other morphs in H. placei, and all 3 morphs were present in sheep and goats with the linguiform form being predominant. Genetic characterization of the 3 species was performed by means of Random Amplified Polymorphic DNA (RAPD). Three groups were obtained from analysis of these data: 1 group with individuals of H. contortus, 1 group with individuals of H. placei, and 1 group with individuals of H. longistipes. This indicated that, although the 3 species were valid, H. contortus and H. placei were more similar. Intraspecific variability was 2-fold higher in H. contortus than in the 2 other species. The ecological, morphological and genetical studies showed that H. longistipes, H. placei and H. contortus could be arranged in increasing order of variability.
Proteinases in the excretory/secretory products (ES) of adultTrichinella spiralis
Authors: Todorova V. K. , Knox D. P. , Kennedy M. W. 
Published: June 2009

SUMMARYAdultTrichinella spiraliswere maintainedin vitrousing defined media and the material excreted/secreted (ES) during this time examined for proteolytic enzyme (proteinase) activity using an azocasein assay and gelatin-substrate gels. Several discrete proteinases in the size range 14–100 kDa were observed with optimal activity at pH 7·5. The use of a class-differentiating panel of proteinase inhibitors indicated that serine proteinases were predominant although some inhibition was evident in the presence of cysteine and metalloproteinase inhibitors. Of a panel of potential natural protein substrates tested, ES proteinases only degraded fibrinogen and plasminogen and degradation was, in part, susceptible to the action of serine, cysteine and aspartyl proteinase inhibitors. In addition, antibody harvested from immune but not normal mice inhibited ES proteinase activity, an observation of relevance to the immunobiology of Trichinosis.
Phylogenetic relationships between Toxoplasma and Sarcocystis deduced from a comparison of 18S rDNA sequences
Authors: Ellis J. T. , Luton K. , Baverstock P. R. , Whitworth G. , Tenter A. M. , Johnson A. M. 
Published: June 2009

SUMMARYThe current taxonomy of parasites in the genus Sarcocystis is largely based on morphological characteristics as well as on host specificity and life-cycle structure. Recently, phylogenetic analyses of partial ribosomal RNA (rRNA) sequences provided support for paraphyly of Sarcocystis. We have tested the validity of this hypothesis by sequencing the complete 18S rRNA genes of Sarcocystis arieticanis, Sarcocystis gigantea and Sarcocystis tenella and comparing them with gene sequences derived from other taxa of the phylum Apicomplexa. The results obtained from this study do not reject the hypothesis of monophyly of Sarcocystis species, although the bootstrap data were inconclusive for some species.
Histochemical mapping of NADPH diaphorase in the nervous system of the parasitic nematodeAscaris suum
Authors: Bascal Z. A. , Montgomery A. , Holden-Dye L. , Williams R. G. , Walker R. J. 
Published: June 2009

SUMMARYNADPH diaphorase has recently been discovered to be responsible for neuronal nitric oxide (NO) synthase activity in mammals. It thus serves as a histochemical marker for the localization of NO synthase in the nervous system. The histochemical technique was used to map out potential NO-producing neurones in the nervous system of the parasitic nematode,Ascaris suum. Positive staining for NADPH diaphorase was present in various parts of the central nervous system, in particular within selective cell bodies and fibres in the ventral ganglion, the retrovesicular ganglion, ventral and dorsal cords and sublateral lines. Intense staining was also present in the motorneurone commissures, indicating a potential role for NO as a neurotransmitter at the neuromuscular junction. NADPH disphorase-positive neurones were not confined to the central nervous system. Selective staining was also present in the enteric nervous system, in particular the pharynx and in the peripheral nervous system innervating the sensory organs.
The human anion transport protein, band 3, contains a CD36-like binding domain forPlasmodium falciparum-infected erythrocytes
Authors: Crandall I. , Sherman I. W. 
Published: June 2009

SUMMARYEpitope mapping of a murine monoclonal antibody (mAb), 5H12, prepared against livePlasmodium falciparum-intected red blood cells indicated that the epitope consisted of amino acid residues 474–487 of the human anion transport protein, band 3. mAb 5H12 enhanced cytoadherence, but inhibited the CD36-like mediated resetting. A synthetic peptide based on the sequence of the epitope (FSFCETNGLE) blocked both resetting and cytoadherence, suggesting that this amino acid sequence may form the CD36-like receptor. The CD36-like region of band 3 was antigenically distinct from platelet or endothelial CD36.
Dissociation of early and late protective immunity to the nematodeNippostrongylus brasiliensisin Brown Norway and Fischer-344 rats
Authors: Uchikawa R. , Yamada M. , Matsuda S. , Tegoshi T. , Nishida M. , Kamata I. , Kuroda A. , Arizono N. 
Published: June 2009

SUMMARYWorm expulsion of, and IgE and interferon (IFN)-γ responses to,Nippostrongylus brasiliensiswere studied in 2 rat strains, Brown Norway (BN) and Fischer (F)-344. BN rats expelled the majority of worms by day 14 post-infection (p.i.) with approximately 6% of worms surviving for at least 3 weeks. In F-344 rats, worm expulsion was delayed by 2 days relative to that in BN, while the numbers of residual worms were significantly fewer than in BN, suggesting that different immune mechanisms are involved in early and late phases of immunity. Total serum IgE, as well asin vitroIgE production by mesenteric lymph node (MLN) cells, was increased 2 weeks p.i., the levels being markedly higher in BN than in F-344 rats. Serum rat mast cell protease II was also increased more significantly in BN than in F-344 rats. In contrast, production of IgG2a and IFN-γ by MLN and spleen cells was found to be higher in F-344 than in BN rats. These results indicate that the early worm expulsion is correlated with the host IgE and mast cell responsiveness, whereas the persistence of infection in the late period may be controlled by different immune mechanisms.