bluuebunny/crossref_metadata_2025_split huggingface dataset:
Schistosoma: analysis of monoclonal antibodies reactive with the circulating antigens CAA and CCA
Authors: Deelder A. M. , Van Dam G. J. , Kornelis D. , Fillié Y. E. , Van Zeyl R. J. M. 
Published: June 2009

SUMMARYUsing spleen cells of mice infected or immunized respectively with cercariae or antigen preparations ofSchistosoma mansoni, S. haematobiumorS. japonicummonoclonal antibodies (mAbs) were produced against the schistosome gut-associated antigens CAA (circulating anodic antigen) and CCA (circulating cathodic antigen). Fusions nearly exclusively produced either anti-CAA (n= 25) or anti-CCA mAbs (n= 55) with a strong isotype restriction (IgM, IgG1 and IgG3) against both antigens, the majority of anti-CAA mAbs being IgG1 and the majority of anti-CCA mAbs being IgM. The mAbs, which on the basis of their selection were reactive with multiple carbohydrate epitopes of CAA or CCA, were applied in different immunological techniques including immunofluorescence, a dot immunobinding assay and immuno-electrophoresis to study the epitope repertoire. Anti-CAA mAbs were found to be reactive with 5 different epitopes, none of which occurred as multiple epitopes on eggs. Anti-CCA mAbs, on the other hand, recognized at least 10 different epitopes, while 44% of anti-CCA mAbs recognized epitopes common to the adult worm and the egg. Both CAA-and CCA-epitopes were found to be developmentally expressed at the level of the tegument in cercariae, schistosomula and 5-day-old lung worms, but in the adult worm were primarily found in the gut. Thus, the production of panels of mAbs has not only resulted in the selection of reagents optimally performing in diagnostic immunoassays, but also allowed a more detailed study of the epitope repertoire of these important schistosome antigens.
Differentiation between culture-derived insect stages ofT. brucei,T. vivax, T. congolenseandT. simiaeusing a monoclonal antibody-based dot–ELISA
Authors: Bosompem K. M. , Assoku R. K. G. , Nantulya V. M. 
Published: June 2009

SUMMARYA sensitive and specific nitrocellulose (NC) membrane-based dot–ELISA, utilizing a panel of monoclonal antibodies (mAbs), was developed for differentiation betweenin vitro-derivedprocyclic forms ofTrypanosoma brucei,T. congolenseandT. simiae, and epimastigotes ofT. vivax. Trypanosomes in suspension were applied onto NC membrane in dots and probed with unlabelled trypanosome species-specific mAbs. Bound mAb was revealed by enzyme labelled anti-mouse IgG and precipitable chromogenic substrate. The assay detected the aforementioned trypanosome species in both single and artificially mixed preparations. TenT. brucei, 4T. vivax, 7T. congolenseand 3T. simiaeprocyclic stocks and clones from different geographical areas were tested and identified using the specific mAbs in the dot–ELISA which had a specificity of 100%. Some of theT. brucei,T. congolenseandNannomonas-specific mAbs could detect as few as 10 trypanosomes/dot, whilst 1T. vivaxmAb was able to detect a minimum of 100 trypanosomes/dot in monospecies preparations. A concentration of 1 × 104trypanosomes/μ/dot was eventually determined as ideal for testing in the dot–ELISA. Antigen dots stored at 4 °C under desiccated conditions did not show any loss in activity for up to 90 days. However, when stored under similar conditions at room temperature (17–26 °C), theT. congolense-specific antigen remained unaffected up to 60 days, and then showed decreased activity when tested on day 90.
The induction ofTrypanosoma cruzitrypomastigote to amastigote transformation by low pH
Authors: Tomlinson S. , Vandekerckhove F. , Frevert U. , Nussenzweig V. 
Published: June 2009

SUMMARYFollowing cell invasion,Trypanosoma cruzitrypomastigotes transform into amastigotes, which are the mammalian replicative forms of the parasite. Although amastigotes represent a critical stage in the life-cycle ofT. cruzi, little is known of the factors controlling trypomastigote to amastigote transformation. Kanbera et al. (1990) observed that exposure of trypomastigotes to acidic pH induced their transformation into rounded forms resembling amastigotes. We confirm their observation and, using two strains ofT. cruzi, establish that these transformants are ultrastructurally and biochemically indistinguishable from natural amastigotes. Incubation of trypomastigotes in medium at pH 5·0 for 2 h was sufficient to trigger their transformation into forms resembling amastigotes. Electron microscopical analysis confirmed that the kinetoplast structure, and general morphological features of the acid-induced, extracellular amastigotes were indistinguishable from those of intracellular-derived amastigotes. The extracellular transformation was accompanied by the acquisition of the stage-specific surface antigen of the naturally transformed amastigotes (Ssp-4), and loss of a stagespecific trypomastigote antigen (Ssp-3). Trypomastigotes incubated at neutral pH did not transform into amastigotes, and did not acquire the Ssp-4 epitope or lose the Ssp-3 epitope. Finally, acid-induced amastigotes subsequently incorporated [3H]thymidine into their DNA, indicating that the important replicative property of intracellular amastigotes is also exhibited by these in vitro transformants. This effect of low pH appears to be of physiological relevance, and acid-induced extracellular transformation appears to represent a valid experimental technique for studies of the molecular mechanisms involved in the differentiation process.
Sialic acid analysis and tritium-labelling of sialoglycoproteins of mouse erythrocytes infected withPlasmodium berghei
Authors: Howard R. J. , Seeley D. C. , Kao Vivien , Wember Margreat , Schauer R. 
Published: June 2009

SUMMARYSchizont-infected red blood cells (SI-RBC) fromPlasmodium berghei-infected mice contain between 2 and 10 times as much sialic acid as uninfected RBC from the same blood (99–550 μg/1010RBC versus 33–65 μg/1010RBC). Total RBC samples from infected animals containing up to 63% ring- and trophozoite-infected cells had identical sialic acid contents to purified RBC samples (of < 3% parasitaemia) from the same blood (52–64 μg/1010RBC). We conclude that RBC containing immature parasites have the same sialic acid content as uninfected RBC from infected blood and that total cellular sialic acid increases during maturation to the schizont stage. Uninfected RBC from infected blood had 25–50% as much sialic acid as normal mouse RBC (33–65 μg/1010RBC versus 126 μg/1010RBC). There were no qualitative changes in RBC sialic acids, all RBC samples having 60–70%N-acetyl neuraminic acid, 30–40%N-acetyl-9-O-acetylneuraminic acid and 5–10%N-gly colylneuraminic acid. The quantitative changes we observed during infection must reflect changes in murine sialoglycoconjugates, as we have shown elsewhere that Plasmodia do not synthesize or contain sialic acids. Since the sialic acid composition of mouse serum glycoconjugates is quite different to that of the RBC fractions studied here, the quantitative data suggest that part of the sialic acids of the uninfected RBC has been transferred to SI-RBC. With higher molar ratios of periodate to substrate than generally used, we were able to radio-isotopically label normal murine sialoglycoproteins on SI-RBC and purified uninfected RBC from infected blood by the periodate/NaB3H4method. Several new proteins were then tritiated with SI-RBC but these proteins may be intracellular and could even lack sialie acid.
Parasite-altered behaviour: is the effect of Toxoplasma gondii on Rattus norvegicus specific?
Authors: Berdoy M. , Webster J. P. , Macdonald D. W. 
Published: June 2009

SUMMARYThe effect of Toxoplasma gondii on rat behaviour was assessed in a colony of 36 free-ranging wild/laboratory hybrid rats allowed to compete freely for food and mates in a (100 m2) outdoor naturalistic enclosure. T. gondii infection had no effect on social status or mating success, both the product of costly and competitive activities. However, the propensity to explore novel stimuli in their environment was higher in infected than uninfected individuals. These results are consistent with the hypothesis that T. gondii only affects the behavioural traits which selectively benefit the parasite, rather than causing a general alteration of rat behaviour.
Effects of endotoxin and dexamethasone on cerebral malaria in mice
Authors: Neill A. L. , Hunt N. H. 
Published: June 2009

SUMMARYCBA/T6 and DBA/2J mice inoculated withPlasmodium bergheiANKA (PbA) develop cerebral involvement 6–8 days post-inoculation, from which the CBA mice almost invariably die and the DBA mice recover. Dexamethasone (DXM; 80 mg/kg) given to inoculated CBA mice twice, on day 3 and again within 48 h, reduced the cerebral symptoms and prevented death from cerebral malaria. Plasma tumour necrosis factor (TNF) levels, which increased at the time of the cerebral symptoms, were also reduced in these DXM-treated mice. Intravenously administered Evans Blue, a dye which binds to albumin, diffused extensively across the blood-brain barrier only during the period of cerebral symptoms, in proportion to the severity of the cerebral symptoms and the disease. In PbA-infected CBA mice, cerebral symptoms and the amount of Evans Blue diffusing into the brain tissue were both reduced by DXM treatment, but only if the steroid was given on day 3 and again within 48 h. Endotoxin injected intravascularly into PbA-infected DBA mice after day 5 resulted in an exaggeration of cerebral symptoms and death between days 6 and 9. Plasma TNF and the amount of Evans Blue in the brain parenchyma increased above normal levels in these mice. Endotoxin injections had only minor effects on the severity of the cerebral symptoms in PbA-infected CBA mice and did not cause the animals to die sooner.
A quick-frozen, freeze-fracture and deep-etched study of the cuticle of adult forms ofStrongyloides venezuelensis(Nematoda)
Authors: Martinez A. M. B. , De Souza W. 
Published: June 2009

SUMMARYThe cuticle of adult forms ofStrongyloides venezuelensiswas studied by routine transmission electron microscopy, conventional freeze-fracture and also using quick-freeze and deep-etch techniques. In routine thin sections the cuticle ofS. venezuelensiscomprises 7 layers: epicuticle, outer cortical, inner corticcal, external medial, internal medial, fibrous and basal. Observation of replicas of specimens fractured across the thickness of the body wall, revealed at the epicuticle an ordered array of particles accompanying the cuticular annulations. At the level of the cortical and medial layers we observed few scattered particles embedded in an amorphous matrix without a particular arrangement. The fibrous layer was represented by several parallel lines of ordered particles of similar size. In tangentially fractured specimens, the epicuticle cleaves readily exposing 2 faces, one exhibiting intramembranous particles without any particular arrangement, immersed in a smooth matrix (P face), and the other showing depressions and very few particles (E face). In replicas of fractures submitted to etching, we observed at the level of the cortical, medial fibrous and basal layers an interconnecting fibrous and globous structure which was organized in a different direction at the fibrous layer. The association of freeze-fracture to deep-etch technique revealed the internal structural organization of the cuticle layers showing details that were not seen before using conventional freeze–fracture technique.
Ecology of anti-microbials produced by bacterial associates ofSteinernema carpocapsaeandHeterorhabditis bacteriophora
Authors: Jarosz J. 
Published: June 2009

SUMMARYBased on the ability of bacterial associates of entomopathogenic nematodes to produce antibiotic compounds on artificial media, it has been commonly accepted thatXenorhabdussp. andPhotorhabdussp. inhibit a wide range of invading microorganisms in insects infected withSteinernemaspp. orHeterorhabditisspp. Therefore, the question of whether antibiotic compounds produced by the primary form of bacterial symbionts associated mutualistically withS. carpocapsaeandH. bacteriophoraexplain why insect carcasses do not putrefy but provide nutritional requirements for insect parasitic rhabditoid nematodes to complete their life-cycle was examined. Laboratory bioassays of anti-bacterial activity on nutrient agar and during parasitism in larvae ofGalleria mellonellahave confirmed earlier observations thatin vitrocolonies of the primary form ofX. nematophilusandP. luminescensproduced agar-diffusible antibiotic compounds of a broad spectrum of anti-bacterial activity; their role in parasitism seems doubtful, however. This hypothesis is supported by a low antibiotic potency of a limited spectrum of anti-bacterial activity throughout the life-cycle of the parasites, principally inGalleriainfected withS. carpocapsae. Since the lack of putrefaction cannot be explained simply by antibiotic inhibition of contaminating bacterial microflora, other competition mechanisms must be operating in parasitized insects. I postulated that a rapid and massive colonization of the insect body by nematophilic bacteria creates unfavourable conditions for the growth and multiplication of bacterial (proteolytic) contaminators making the insect carcass decay-resistant. In the case ofH. bacteriophora, low antibiotic activity at an early stage of parasitism could support the colonization byP. luminescensof the host.
Selection alters the pattern of emergence from the host cadaver in the entomopathogenic nematode, Steinernema glaseri
Authors: Stuart R. J. , Lewis E. E. , Gaugler R. 
Published: June 2009

SUMMARYWe used selection to test for a genetic component to the pattern of emergence of infective juveniles from the host cadaver in the entomopathogenic nematode, Steinernema glaseri (Steiner), and whether other traits would respond to selection on this major and complex life-history character. We selected for early (‘ fast’) and late (‘ slow’) emerging lines by perpetuating nematodes that emerged on the first and after the seventh day of emergence respectively. After 12 cycles of selection, the pattern for the slow line but not the fast line differed significantly from the base population. Cumulative emergence for the slow line was less than the base population from Days 4 to 14 of the 18-day emergence period. The maximum difference occurred on the fourth day when 72·6% of emergence was complete for the base population but only 55·4% for the slow line. Decreases in infective juvenile size over the emergence period were consistent with the change in emergence pattern, but variation in sex ratios was not. No differences in infectivity were found. These results indicate that the emergence pattern has a genetic component, and that genetic variability for this trait occurs in natural populations. Furthermore, the asymmetric response to selection suggests that our field population is under strong selection for a highly skewed early emergence.
The effect of proteases and iodination on the adherent behaviour of Plasmodium falciparum-infected erythrocytes
Authors: Crandall I. , Demers D. , Sherman I. W. 
Published: June 2009

SUMMARYPlasmodium falciparum-infected erythrocytes were treated with proteases (trypsin, chymotrypsin, pronase, or V8 protease) or iodinated and the effect of these treatments on the cytoadherent behaviour of the cells was determined. As previously observed, protease treatment reduced cytoadherence. However, it was also found that the P. falciparum-induced adhesin, pfalhesin, was not removed by protease treatment. Gelatin flotation experiments and scanning electron microscopical examination of the treated cells indicated that protease exposure resulted in changes in the knob structures on the cells, which are known to affect the adherent behaviour of the cells. Iodination was found to be an effective method of inactivating pfalhesin.
Parasite-altered behaviour: impact of infection and starvation on mating inBiomphalaria glabrata
Authors: Rupp J. C. 
Published: June 2009

SUMMARYVery little is known about parasite-altered mating behaviour. This paper describes two experiments on the impact of infection and starvation on mating inBiomphalaria glabratasnails. In the first experiment, snails were infected with the parasitic trematodeSchistosoma mansoni. During both the early and the late stages of infection, snails were allowed to mate with individuals of the same infection status and uninfected controls. Their mating activities were filmed and later analysed. The mating frequencies of patently infected (shedding) snails were found to be lower than those of controls. This is thought to result from stress induced by the pathology. Successfully infected snails were found to mate more often as males than as females. This is seen as a compensation for the reduced fecundity caused by trematode infection. Successfully infected snails also exhibited partner choice. More matings were found between snails of the opposite infection status than among snails of the same infection status. This may be explained by the good genes hypothesis and can be seen as a specific response to schistosome infection. In the second experiment, starved snails were allowed to mate with starved and control snails. They mated less often than controls and more often as males than as females, controls showing the opposite pattern. This may be considered to be a general stress response. No partner choice has been found with starved snails. It is suggested that partner choice in infected snails occurs in response to specific rather than general stress.
Neutrophil granule proteins: evidence for the participation in the host reaction to skin microfilariae ofOnchocerca volvulusafter diethylcarbamazine administration
Authors: Gutiérrez-Peña E. J. , Knab J. , Büttner D. W. 
Published: June 2009

SUMMARYThe participation of neutrophil granulocytes in the cellular reaction to skin microfilariae ofOnchocerca volvuluswas studied by immunohistochemistry. Skin biopsies were obtained from adult Liberian and Ugandan patients with generalized onchocerciasis after exposure to topically applied diethylcarbamazine (DEC) and from untreated patients. After DEC many damaged microfilariae were observed either in dermal infiltrates or in epidermal microabscesses consisting both of neutrophils and eosinophils. Infiltrates and microabscesses contained some intact granulocytes and many neutrophils releasing myeloperoxidase, elastase, lactoferrin, defensin, lysozyme, α1-antitrypsin and α1-antichymotrypsin. Eosinophils discharged peroxidase and cationic proteins. Released granule proteins and remnants of disrupted granulocytes were found on the surface and in close proximity of damaged microfilariae in dermal infiltrates and epidermal microabscesses. In larger microabscesses neutrophils were predominant. These observations show that neutrophils and not only eosinophils recruit, accumulate, localize around and release their helminthotoxic granule proteins such as myeloperoxidase onto or closely around skin microfilariae ofO. volvulusafter topical DEC administration. The association between these processes and the damage of the microfilariae indicated that neutrophils together with eosinophils attack and damage microfilariae ofO. volvulusafter DEC treatment in the skin.
Hymenolepis diminuta: metacestode-induced reduction in the synthesis of the yolk protein, vitellogenin, in the fat body of Tenebrio molitor
Authors: Webb T. J. , Hurd H. 
Published: June 2009

SUMMARYVitellogenin synthesis by the fat body has been monitored using in vitro culture and immunoprecipitation. This system was found to be efficient for measuring vitellogenin production in both non-infected Tenebrio molitor and those infected with Hymenolepis diminuta. In fat bodies from infected beetles, vitellogenin production was decreased by up to 75% (day 24 post-infection) and, at all times investigated, vitellogenin synthesis was significantly below control levels (days 3–30 post-infection). Incubating fat bodies from control insects with isolated metacestodes indicated that this may be a direct effect by the parasite which is developmental stage-specific. Stage II, but not stage III–IV, nor heat-killed parasites could bring about this decrease in vitellogenin. In addition, these effects may be density dependent within the range of 2–20 parasites per fat body; only 2 metacestodes were necessary to cause a significant decrease. Since metacestodes do not take up vitellogenin, nor limit the amount of [14C] leucine available to the fat body for vitellogenin production, it is conceivable that the parasite produces a potent inhibitor of vitellogenin synthesis, or a molecule which induces cells within the fat body to do so.
Species-specific DNA probes for the identification of African trypanosomes in tsetse flies
Authors: Gibson W. C. , Dukes P. , Gashumba J. K. 
Published: June 2009

SUMMARYWe have obtained 5 specific DNA probes for African trypanosomes of the subgenera Trypanozoon and Nannomonas. Each probe consists of one repeat unit of the major repetitive DNA (satellite DNA) of each species or intra-specific group. One probe hybridized with all members of subgenus Trypanozoon (except T. equiperdum which was not tested). In subgenus Nannomonas, one probe recognized T. simiae, but 3 probes were needed to identify all stocks of T. congolense available. Each of the 3 latter probes recognized trypanosomes from one of the 3 major groups of T. congolense previously defined by isoenzyme characterization, i.e. savannah, forest and Kenya coast types. As few as 100 trypanosomes could be unequivocally identified by dot blot hybridization and individual trypanosomes could be identified by in situ hybridization. We show how this simple methodology can be used in the field for the identification of immature and mature trypanosome infections in tsetse.
Hymenolepis nana: the fine structure of the embryonic envelopes
Authors: Fairweather I. , Threadgold L. T. 
Published: June 2009

SUMMARYThe fine structure of the envelopes surrounding hatched and unhatched oncospheres of Hymenolepis nana has been investigated by transmission and scanning electron microscopy (SEM), together with light microscope histochemical observations of JB-4 embedded material. The oncosphere is surrounded by 3 layers – the capsule, the outer envelope and the inner envelope, the latter giving rise to the embryophore and the ‘oncospheral membrane’. An additional layer – the polar filament layer – lies between the ‘oncospheral membrane’ and the oncosphere. Shell material is deposited on the capsule as a thin layer. It is secreted by the outer envelope, which degenerates once shell formation is complete. The uterus may also contribute to shell formation. The embryophore forms a thin, incomplete and peripheral layer within the inner envelope. In the basal region of this envelope, partial development of an ‘oncospheral membrane’ takes place, but it does not become detached as a separate layer. The polar filaments, which are characteristic of the oncosphere of H. nana, are derived from the epithelial covering of the oncosphere itself, which delaminates to form a separate polar filament layer. The filaments arise from knob-like projections at opposite poles of this layer. The design of the embryonic envelopes in H. nana show a number of modifications from the basic cyclophyllidean pattern, and these can be related to the demands of its ‘direct’ life-cycle.
Polymorphism inPlasmodium vivaxMSA1 gene – the result of intragenic recombinations?
Authors: Cheng Q. , Stowers A. , Huang T.-Y. , Bustos D. , Huang Y.-M. , Rzepczyk C. , Saul A. 
Published: June 2009

SUMMARYThe diversity in a 925 bp portion of thePlasmodium vivaxMSA1 gene in isolates from the Philippines, China, the Solomon Islands and Papua New Guinea was investigated. A total of 74 base pair changes was found in the amplified fragment from 18 isolates. Most of these changes were single or double base pair substitutions. In several regions, these point changes were tightly linked with one set always present or always absent in the different isolates. Seven such blocks were identified. These blocks were present in different combinations in the different isolates indicating that extensive intragenic recombination has occurred.