bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibitory, opsonic and cytotoxic activities of monoclonal antibodies against asexual erythrocytic stages ofPlasmodium falciparum
Authors: Li J. L. , Li Y. J. 
Published: June 2009

SUMMARYA range of monoclonal antibodies specific forPlasmodium falciparumwere testedin vitrofor their abilities to inhibit the multiplication of a partially synchronized culture ofP. falciparum, to augment the phagocytosis of the parasites by macrophages, and to enhance the killing of parasites by peritoneal cells depleted of adherent cells. Seven of 17 monoclonal antibodies, ranging from culture supernatant fluid and ascitic fluid to purified IgG, showed dose- and time-dependent inhibition of parasite growthin vitro.At a concentration of 0·6 mg/ml, the inhibitory capacity of these monoclonal IgGs was above 94% over a 3-day culture period, much higher than that of the relevant polyclonal IgG. Four of 6 monoclonal antibodies tested augmented the phagocytosis of the parasites by macrophages, which occurred as a result of opsonization of the parasites. Four of 7 monoclonal antibodies examined showed cytotoxic activity on malaria parasites. Peritoneal cells depleted of adherent cells were capable of killing the parasites in the presence of monoclonal antibodies. These results indicate that there may be ‘monofunction’, ‘bifunction’, and ‘multifunction’ types of monoclonal antibodies againstP. falciparum.The putative protective antigen of malaria parasites purified by ‘multifunctional monoclonal antibody’ affinity chromatography may have potential interest as a vaccine against the parasite or as an immunodiagnostic reagent for human malaria.
Schistosoma mansoni:stage-dependent membrane vesiculation and parasite killing induced by a cytotoxin fromPseudomonas aeruginosa
Authors: Ruppel A. , Breternitz R. , Lutz F. 
Published: June 2009

SUMMARYWe have examined the interaction betweenSchistosoma mansoniand a cytotoxin fromPseudomonas aeruginosaknown to affect a variety of cell types through the formation of membrane pores. The killing effect of the cytotoxin onS. mansoni in vitrowas strongly dependent on the parasite developmental stage. Skin schistosomula were most sensitive, while 4-week-old or older parasites were less so. In contrast, lung schistosomula were relatively resistant and juvenile mesenteric forms younger than 28 days were almost completely refractory to the action of the toxin. A sharp increase in sensitivity to the toxin was observed between 27 and 28 days of parasite age with a parasite length of about 1·80 mm appearing as the threshold. Thus, the schistosome sensitivity to the cytotoxin changed during parasite development in a way similar to the known sensitivity of the worms toin vitroimmune attack. Killing of the parasites by the cytotoxin was preceded by the formation of vesicles which, in the case of adult worms, detached easily from the parasites. Evidence obtained by electron microscopy and by immunofluorescent assays with living worms demonstrated that the outer parasite membrane participated in the formation of the vesicle membrane. Thus, the cytotoxin may be a useful tracer for changes in the properties of the schistosome surface membrane during parasite development.
Surface and species-specific antigens ofSchistosoma haematobium
Authors: Kelly C. , Hagan P. , Knight M. , Hodgson J. , Simpson A. J. G. , Hackett F. , Wilkins H. A. , Smithers S. R. 
Published: June 2009

SUMMARYOf the surface antigens identified by radio-iodination, two-dimensional gel analyses showed no similarities between those ofSchistosoma haematobiumandSchistosoma mansoni, thus providing a basis for the species specificity of these antigens described previously (Simpson, Knight, Hagan, Hodgson, Wilkins & Smithers (1985)Parasitology90, 499–508). The surface antigens ofS. haematobiumwere glycosylated and comprised an acidic polypeptide ofMr17000 as well as a complex set of polypeptides of approximate pI 6–7, which resolved in theMrrange 20000–30000. At least one of the lowerMrforms of this complex is also present in the adult worm. Limited cross-reaction was observed withS. mansoniinfection sera and this may be due to a shared carbohydrate epitope. In contrast, extensive cross-reaction was observed using sera from mice immunized withS. bovis.This pattern parallels the species-specificity of vaccine-induced immunity. Extensive cross-reaction was also observed within cell-free translation products of m-RNA from adult worms ofS. haematobiumandS. mansoniby use of heterologous human infection sera. The few antigens which were species-specific may represent surface antigens.
Co-existence of congeneric species of Acanthocephala: Acanthocephalus lucii and A. anguillae in eels Anguilla anguilla in Ireland
Authors: Kennedy C. R. , Moriarty C. 
Published: June 2009

SUMMARYA population of eels Anguilla anguilla from Lough Derg, R. Shannon, Ireland, harbouring infections of both Acanthocephalus lucii and A. anguillae was studied over three years. Both parasite species had the same intermediate host and eels appeared to be the only definitive host for A. anguillae. Throughout the whole period, A. lucii was the dominant parasite, was over-dispersed throughout the eel population and most frequently occurred as a single species infection. A. anguillae was far less common, its dispersion was close to random at most times and it almost invariably occurred as a mixed species infection. The proportions of the two species remained fairly constant over the period. Despite some indication of site selection in the intestine, the distribution of both species overlapped considerably and there was no evidence of competitive displacement of one species by the other or of resource partitioning in space. The life-histories of both species were similar: they infected eels, bred and were lost from fish at the same time of year and there was no indication of resource partitioning in time. Congeneric species of acanthocephalans can thus co-exist in apparently stable equilibrium in fish as predicted and without any evidence of interactions, but it is still considered that exploitation competition between the species may be occurring in eels.
Comparisons of Heligmosomoides polygyrus primary infection in protein-deficient and well-nourished mice
Authors: Brailsford T. J. , Mapes C. J. 
Published: June 2009

SUMMARYPrimary infections of Heligmosomoides polygyrus were studied in adult male CD1 mice fed on isoenergetic synthetic diets containing either 2% or 20% protein (casein). A slight reduction in food intake was observed during infection, and this was unaffected by diet. Protein deficiency was also found to have no effect upon worm establishment. Evidence was found, though, to suggest that the worms have a more severe effect upon the host in protein-deficient mice. Hypoalbuminaemia was observed due to diet and also infection, and this was synergistic. There was an increase in non-albumin plasma protein during infection which was not effected by diet. The circulating urea concentration was reduced during protein deficiency, as was the level of essential amino acids, but non-essential amino acid levels were raised. An increase in the levels of urea and essential amino acids was observed at day 4 of infection in mice on the 20% diet, but not on the 2% diet. Splenic atrophy occurred during infection, but the splanomegaly that occurred early during infection was proportionally greater in protein-deficient mice. These results are discussed in terms of the pathophysiology of both protein deficiency and infection, and comparisons are made with human malnutrition syndromes.
The distribution and abundance of Enterobius vermicularis in a South Indian fishing community
Authors: Haswell-Elkins M. R. , Elkins D. B. , Manjula K. , Michael E. , Anderson R. M. 
Published: June 2009

SUMMARYThe distribution and abundance of Enterobius vermicularis in a fishing community in South India, as determined by counting worms expelled following mass anthelmintic chemotherapy, was examined in samples of patients stratified by age, sex and family grouping. The results of a worm expulsion study in January 1984 are compared with those of a second expulsion programme in November 1984, following an 11-month period of reinfection. The prevalence of Enterobius infection was consistently high in all age groups of both males and females. A comparison of the overall prevalence and intensity of infection in the January and November surveys revealed significant increases in both the percent infected and the mean number of worms harboured in November relative to the initial level. No significant trends in the intensity of Enterobius according to host age or sex were detected in either survey. The frequency distribution of Enterobius was found to be highly aggregated in the population as a whole and within age groups. At both sampling dates, the most heavily infected 25% of the community harboured over 90% of the total pinworms recovered. There was a significant pattern within most age groups for individuals to re-acquire worm burdens of a similar magnitude to their initial pre-treatment burdens. Heavy infections were found to be associated with household. A selective or targetted approach to treatment of heavily infected individuals or households is likely to be an efficient means of reducing parasite abundance on a community-wide basis. It must be stressed, however, that treatment must be applied at frequent intervals in order to achieve a long-term reduction in pinworm abundance and to avoid the possibility of increasing the intensity of infection, as was observed in this community.
A repetitive deoxyribonucleic acid sequence distinguishesTrypanosoma simiaefromT. congolense
Authors: Majiwa P. A. O. , Webster P. 
Published: June 2009

SUMMARYThe dominant repetitive deoxyribonucleic acid (DNA) sequence in the genome of a clone ofTrypanosoma(Nannomonas)simiaehas been identified and cloned as a recombinant plasmid. The recombinant plasmid was used in hybridization analyses of DNA samples obtained from various trypanosome species and subspecies. The results indicated that theT. simiaerepetitive DNA sequence hybridized with DNA derived only fromT. simiae; it did not hybridize with DNA derived from clones or stocks ofT. congolense, or from any other trypanosome species examined. A preliminary characterization of the cloned DNA sequence and its use in the identification ofT. simiaeof similar genotypes are presented.
Destruction of intracellular and isolatedLeishmania mexicana amazonensisamastigotes by amino acid amides
Authors: Rabinovitch M. , Zilberfarb V. 
Published: June 2009

SummaryL-amino acid esters such as leucine methyl ester (Leu-OMe) destroyLeishmania mexicana amazonensisamastigotes by a mechanism which may involve hydrolysis of the compounds by parasite enzymes. Moreover, several esters (e.g. Ile-OMe) prevent the killing of parasites by Leu-OMe, perhaps by inhibition of the hydrolytic enzymes. We show here that certain amino acid amides are also leishmanicidal. Killing ofLeishmaniawithin macrophages was assessed microscopically, and that of isolated amastigotes was measured by reduction of the tetrazolium MTT. Amino acid amides were generally less active than the methyl esters and several were more toxic to the macrophages, as determined by inspection of Giemsa-stained preparations. Ranks of activity of the amides on isolated amastigotes were Trp > Leu > Phe > Met > Tyr. The amides of Ala, Gly, Val, Ile, His and D-Leu were inactive. This pattern of activity is similar to that of amino acid methyl esters. Ile-NH2and a few other amides protected intracellular as well as isolated parasites from killing by Leu-OMe. Conversely, Ile-OMe reduced the toxicity of Leu-NH2for isolated amastigotes. None of the esters or amides assayed prevented the destruction ofLeishmaniaby Trp-NH2. The results are compatible with the view that amino acid esters and amides may be recognized by the same or similar parasite enzymes.
Population dynamics of a thelastomatid nematode of cockroaches
Authors: Zervos S. 
Published: June 2009

SummaryBlatticola monandrosZervos lives in the hind gut of the endemic New Zealand cockroachParellipsidion pachycercumJohns. A field survey showed that infection prevalence was high (54 %) in small nymphs and increased further with cockroach size to a maximum (92 %) in penultimate nymphs. Variance to mean ratios and the Chi-square test for goodness of fit of a Poisson distribution provide strong evidence that the distribution of the nematode was not clumped (over-dispersed) or Poisson (random) but under-dispersed in most host size classes. The modal infrapopulation type consisted of 1 adult male and 1 adult female. Other infrapopulations were transitional to this type. Monogamous infrapopulations increased in prevalence with increased host size. Juvenile males were uncommon and probably develop faster into adults than juvenile females. Infrapopulations with 2 juvenile males were very rare and no cockroach contained 2 adult males, although some contained 2 adult females. Seasonal variations in prevalence and infrapopulation structure were slight over a 3 year period, except during one unusually dry summer. During the drought, prevalence of monogamous infrapopulations and of transitional infrapopulations were lowest, while prevalence of single-worm and single-sex infrapopulations were greatest. It is evident that competition between females reduces fecundity. When only 1 adult female nematode is present in an adult cockroach, more eggs are produced than the total produced if 2 adult females are present. Eggs were produced cyclically with short periods of high egg production interspersed with several days of very low or no egg production. Most eggs produced on any one day were attached to the outer surface of only 1 of the up-to-6 faecal pellets produced by the host/day. Mechanisms which may regulate infrapopulations and control reproductive competition and cyclical egg production are discussed. It is suggested thatB. monandrosregulates its own infrapopulation.
Use of restriction fragment length polymorphisms (RFLPs) to distinguish between nematodes of pathogenic significance
Authors: Cameron M. L. , Levy P. , Nutman T. , Vanamala C. R. , Narayanan P. R. , Rajan T. V. 
Published: June 2009

SummaryThe availability of restriction fragment length polymorphisms (RFLPs) would be useful for studying the extent of diversity among morphologically indistinguishable populations of filarial parasites. Such polymorphisms may be useful in correlating various physiological and clinical differences with parasite heterogeneity. In order to identify such RFLPs, we isolated DNA from microfilaria of 6 filarial species (Acanthocheilonema viteae, Brugia malayi, Brugia pahangi, Dirofilaria immitis, Litomosoides carinii and Setaria digitatum), digested the DNA with several restriction endonucleases, prepared Southern blots and probed with 32P-labelled DNA probes. The patterns of fragments generated using two restriction endonucleases, Mbo I and Tag I, in combination with two probes, rDNA from the free-living soil nematode Cenorhabditis elegans, and pBM103, an anonymous DNA probe from B. malayi, unequivocally distinguish between all 6 of the species. To ensure that the differences we observed between the species represent true interspecies variation rather than fortuitous individual variations we analysed DNA from several individual B. malayi and B. pahangi worms. The individual B. malayi worms demonstrated restriction profiles that were invariant, as did the individual B. pahangi worms, demonstrating that the differences we observed were true interspecies variations.
Immune response of guinea-pigs to chemically abbreviated prepatent Metastrongylus apri infection
Authors: Kumar V. , Mortelmans J. 
Published: June 2009

The effect of chemical abbreviation of the primary infection dose (PID) of 160 infective larvae of Metastrongylus apri on the immune status of the guinea-pig host was studied. The criteria used for assessing the status of immunity consisted of clinical manifestations following administration of a challenge infection dose (CID) of 800 infective larvae of M. apri, the rate of worm recovery 15 days post-CID and the rate of mortality following administration of CID.Among the guinea-pigs of the main experimental group, where 15-day-old PID was abbreviated by two parenteral doses of levamisole*, a strong immunity to CID given 35 days post-PID was built-up. Against this, all the guinea-pigs of a control group, which did not receive PID, died between 16 and 22 days post-CID.The increase in serum gamma-globulin level of the guinea-pigs, where the PID was abbreviated chemically, suggested that the rise of this globulin fraction in the serum could be in some way related to the resistant state of guinea-pigs.
The tylenchid (Nematoda) egg shell: structure, composition and permeability
Authors: Bird Alan F. , McClure M. A. 
Published: June 2009

The fine structure of egg shells of four different genera belonging to the order Tylenchida has been examined. The species examined were Meloido-gyne javanica, Rotylenchulus reniformis, Tylenchulus semipenetrans and Pratylenchus minyus. They are all similar in their basic structure, being composed of vitelline membrane, chitin and lipid layers, but there is considerable variability in the thickness of these layers.We have retained the conventional nomenclature because of its convenience, but it is clear that these layers have a variety of chemical components. However, they do appear to contain the compounds from which they take their name. Thus chitin occurs in the chitin layer, and lipid in the lipid layer. The latter is removed by the technique used in isolating the shell from the egg. Chemical analysis of the hydrolysis products of these shells has revealed a high (35 %) proline content which appears to be a characteristic of those nematode egg shells which have been examined so far. These analyses and treatment with enzymes indicate that the chitin layer is a chitin-protein complex.Experiments on the permeability of eggs of M. javanica at different temperatures indicate that changes in permeability are not due to the melting of a single lipid with a distinct melting point as had been thought in the past. We have found that Arrhenius activation energies calculated from the two slopes of an Arrhenius plot were 17·8 kcal/mol and 43·0 kcal/mol respectively, the transition from one to the other taking place at 62°C. We think that these changes are due to changes in the properties of lipoprotein membranes in the lipid layer. These membranes appear to be of paramount importance in controlling the permeability of the nematode egg shell.
The immunity arising from continuous low-level infection with Eimeria maxima and Eimeria acervulina
Authors: Joyner L. P. , Norton C. C. 
Published: June 2009

Chicks were given daily inoculations of 1 or 5 oocysts of Eimeria maxima or 5 or 20 oocysts of E. acervulina.The inoculations ceased after 20 days with E. maxima or 25 days with E. acervulina when oocyst production had stopped. The responses to subsequent heavy challenges showed that with both species the immunity arising from the serial inoculations was stronger and/or more enduring than that produced by single inoculations of comparable numbers of oocysts.
Contrasts in antigen expression in the erythrocytic and exoerythrocytic stages of rodent malaria
Authors: Suhrbier A. , Wiser M. F. , Winger L. , Harte P. , Newton M. F. , Hodivala K. J. , Nicholas J. , Sinden R. E. 
Published: June 2009

SummaryThe time and Site of expression of five antigens, recognized by monoclonal antibodies raised against blood-stage parasites, were studied in the exoerythrocytic stage ofPlasmodium bergheiusing indirect immunofluorescent antibody staining. Two monoclonal antibodies (W 3. 5, I 2. 6), which stain the cytoplasm of infected erythrocytes, did not stain the cytoplasm of the infected liver cell but stained the parasite itself suggesting a difference in the antigenic architecture of the erythrocytic and exoerythrocytic parasites. Another antibody (17. 6. 1) revealed a further difference in the antigenic composition of the blood and liver-stage parasites being expressed almost exclusively in the former. Two others (C139 and 17. 3. 9) showed broadly similar patterns of expression in these two stages of the malarial life-cycle.
Susceptibility to hydrogen peroxide ofPlasmodium falciparuminfecting glucose-6-phosphate dehydrogenase-deficient erythrocytes
Authors: Kamchonwongpaisan S. , Bunyaratvej A. , Wanachiwanawin W. , Yuthavong Y. 
Published: June 2009

SummaryThe susceptibility to oxidant-mediated killing ofPlasmodium falciparuminfecting normal and glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes was assessed by exposure to hydrogen peroxide generated by the glucose–glucose oxidase system. The parasites infecting G6PD-deficient erythrocytes had markedly greater susceptibility to hydrogen peroxide under a variety of conditions than those infecting normal erythrocytes. In both cases, the killing effect was mediated mainly through the host cells since treatment of the erythrocytes with hydrogen peroxide did not change their relative susceptibility. The parasites were most susceptible during maturation, especially in G6PD-deficient erythrocytes, although a reduction in parasite invasion was also observed. The role of oxidant-mediated killing in the protection of G6PD-deficient hosts fromP. falciparuminfection is discussed.
Biological effects of lithium chloride on the insect trypanosomatidHerpetomonas samuelpessoai
Authors: Nakamura C. V. , Pinto A. S. 
Published: June 2009

SummaryEffects of lithium chloride on growth, differentiation and respiration ofHerpetomonas samuelpessoai, cultivated in a synthetic medium were studied both at 28 and 37 °C. Low concentration of lithium chloride (15 mM) stimulated growth at 37 °C. In addition, the protozoon tolerated high concentrations (60–150 mM) of the salt at both incubation temperatures. In general, 15 mM lithium chloride increased and 150 mM decreased oxygen uptake when glucose, glutamic acid and proline were used as substrates. However, at 28 °C after incubation for 96 h, the highest concentration increased oxygen uptake in the presence of glucose. Sodium butyrate induced cell differentiation inH. samuelpessoaiboth at 28 and 37 °C. High concentration (150 mM) of lithium chloride inhibited cell differentiation ofH. samuelpessoaiinduced by both controlled growth conditions and butyrate addition. The results obtained are described in this paper.
A comparison of fluorescein diacetate and propidium iodide staining andin vitroexcystation for determiningGiardia intestinaliscyst viability
Authors: Smith A. L. , Smith H. V. 
Published: June 2009

SummaryThe viability of 4 human isolates ofGiardia intestinaliscysts using either the fluorogenic vital dyes fluorescein diacetate (FDA) and propidium iodide (PI) orin vitroexcystation was assessed. Whereas viable cysts, as defined byin vitroexcystation were present in each of the 4 isolates, cysts from only 3 of the 4 isolates took up the vital dyes. FDA consistently over-estimated cyst viability whilst PI under-estimated non-viable cysts when compared within vitroexcystation. Followingin vitroexcystation, both FDA and PI stained a proportion of unexcysted cysts indicating that FDA stained cysts which were incapable of excystation, whereas PI did not stain all cysts which were incapable of excystation. One human cyst isolate, which underwentin vitroexcystation, could not be stained with either FDA or PI. In the absence of currently more specific fluorescent indicators of viability, PI alone could be used to determine the lower limit of nonviability in positive water-related samples, where small numbers of cysts are to be expected.