bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of protein composition between schistosomula ofSchistosoma japonicumandS. mansoni
Authors: Maeda S. , Irie Y. , Yasuraoka K.
Published: June 2009

SDS-PAGE analysis revealed that the protein composition of mechanically transformed schistosomula (ms) of a Japanese strain ofSchistosoma japonicumwas essentially similar to that of a Philippine strain ofS. japonicum. However, the protein components ofS. mansonims were remarkably different from those ofS. japonicum. Specific proteins of Mr60–65.and 30 kDa were found in ms ofS. japonicumandS. mansoni, respectively. In skin-penetrated schistosomula (ss) of the two species, a common protein of 67 kDa was detected. Using two-dimensional electrophoresis, strain-specific polypeptides (9 in a Japanese and 11 in a Philippine strain) were identified in ms ofS. japonicum. Mechanically transformed and skin-penetrated schistosomula ofS. japonicum(Japanese) had, respectively, 7 and 10 specific proteins. Four and 1 specific polypeptides were also detected in two-dimensional profiles of ms and ss ofS. mansoni, respectively.
An ultrastructural analysis of cyst wall development in the metacestode ofHymenolepis diminuta(Cestoda)
Authors: Sylvia Richards K. , Arme C.
Published: June 2009

A series of development stages (I–XI) have been devised to describe the development of the cyst wall of the metacestode ofHymenolepis diminuta. The cyst wall possesses tegumentary, muscular, fibrous and inner cyst tissues, the developmental rates and differentiation patterns of which are not identical. The tegumentary tissue differentiates posteriorly. Its microvillus-bearing distal cytoplasm remains simple until scolex retraction, after which rapid increase in depth followed by vacuolation occurs and basal membrane infoldings surround Phase 3 fibrogenesis fibrils. Senescence, which also affects the tegumentary cytons, then ensues. The muscle system development is posteriad and maturation, completed before scolex retraction, is followed by myocyton senescence. Posteriorly differentiated fibroblasts commence Phase 1 fibrogenesis after scolex retraction and the primary fibrous zone is fully established within approximately 6 days. Phase 2 and 3 fibrogenesis develop centrifugally, the fibrils of Phase 2 surrounding the tegumentary cytons and myocytons prior to their senescence, and those of Phase 3 lying more peripherally. The inner cyst tissue, established posteriorly, differentiates anteriorly, centripetally and early, the penultimate stage commencing just before scolex retraction, about 6 days after which the final maturation junctional complexes start development. Neitherin vitroexcystment nor infectivity of the definitive host can be satisfactorily achieved before the initial development of the primary fibrous zone. This may play a skeletal role during excystment, and is shown to be unaffected by the digestive enzymes which cause loss of cytoplasmic integrity in the outer regions of the cyst.
The rostellar tegumentary cytoplasm of the metacestode ofHymenolepis diminuta(Cyclophyllidea: Cestoda)
Authors: Richards K. Sylvia , Arme C.
Published: June 2009

Prior to scolex-retraction, the tegumentary syncytial cytoplasm of the presumptive rostellar region ofHymenolepis diminuta(fromTenebrio molitorkept at 26 °C) is indistinguishable from that of the rest of the cysticercoid. At 1 day after scolex-retraction differentiation of the rostellum has commenced, the tegumentary cytoplasm containing a small number of membrane-bound, ovoid, electron-dense granules which are absent from all other tegumentary regions of the metacestode. By 3 days after scolex-withdrawal there is a substantial increase in the number of ovoid granules within the rostellar tegumentary syncytium and the Golgi systems of the rostellar cytons are highly secretory. At this stage, although the cyst wall tissues are not fully developed, the metacestode is infective. This early and rapid development of the rostellar region presumably enables the ‘adult’ condition to be readily attained. In older metacestodes there is a progressive accumulation of ovoid granules within the rostellar tegumentary cytoplasm, accompanied by a decrease within the rostellar cytons. At 23 days following scolex-retraction the rostellar syncytium has the appearance of that of the adult tapeworm. The rostellar cytons also produce tegumentary discs and vesicles and are therefore regarded as homologous to the other tegumentary cytons of the metacestode.
Hymenolepis nana: the fine structure of the adult nervous system
Authors: Fairweather I. , Threadgold L. T.
Published: June 2009

The fine structure of the nervous system in the scolex and neck region of Hymenolepis nana has been investigated by transmission electron microscopy. A description of the gross neuroanatomy in these regions of the worm is presented. The ganglia, commissures and nerve cords consist of an incomplete cortex of nerve cell bodies, and a core of nerve fibres. A delimiting sheath or capsule is absent. The nerve cell bodies contain a single nucleus with a single nucleolus, mitochondria, many ribosomes, Golgi complexes and vesicles formed within the Golgi cisternae. Numerous sub-surface cisternae are present beneath the outer plasma membrane of the nerve cell body, and the inner surfaces of these cisternae are studded with ribosomes. Some of the cisternae run tangentially into the cytoplasm of the perikaryon, particularly in the vicinity of the Golgi complexes; both sides of these cisternae are studded with ribosomes. From each neuronal perikaryon arise one or more neurites that contain neurotubules, mitochondria, ribosomes and electron-lucent or dense-cored vesicles. Five types of vesicle have been distinguished on the basis of their size and content. The neurites are unmyelinated and form synapses in the neuropile; the synapses possess features typical of those where mechanical strength is of importance. Three types of sensory receptors have been observed in H. nana, two ciliated and one non-ciliated; the latter typically form double or triple nerve endings which terminate within the tegument.
A study of the sensitivity ofLeishmania donovanipromastigotes and amastigotes to hydrogen peroxide. I. Differences in sensitivity correlate with parasite-mediated removal of hydrogen peroxide
Authors: Channon Jacqueline Y. , Blackwell Jenefer M.
Published: June 2009

The sensitivities of promastigotes and amastigotes ofLeishmania donovanito reagent or glucose oxidase-generated hydrogen peroxide (H2O2) were examined in a phagocyte-free system and compared with direct measurements of loss of H2O2due to reaction with the parasite. Using a combined fluorescence dye uptake/dye exclusion viability assay in conjunction with motility and transformation data it was shown that log-phase promastigotes harvested from recently transformed cultures were intermediate in their H2O2sensitivity between amastigotes and log-phase promastigotes harvested from long-term subcultures. It was also observed that, while promastigotes are equally sensitive to either form of H2O2stress, amastigotes are more resistant to single larger amounts of reagent H2O2than to equivalent amounts of H2O2generated over a 1 h period. In each case the respective LD50values obtained for each form of the parasite under each type of H2O2stress correlated with saturation of their ability to remove H2O2from the phagocyte-free system. For both promastigotes and amastigotes there was always a time delay after removal of either form of H2O2stress before H2O2-mediated damage to membranes became apparent. The results suggest that the differential responses of promastigotes and amastigotes to different forms of H2O2stress may depend upon different H2O2scavenging mechanisms examined in more detail in the accompanying paper.
Endocrine responses of protein-malnourished rats infected with Nippostrongylus brasiliensis (Nematoda)
Authors: Ash C. P. J. , Crompton D. W. T. , Lunn P. G.
Published: June 2009

During the course of a primary infection of Nippostrongylus brasiliensis in protein-malnourished rats, plasma concentrations of corticosterone were found to decrease from 0.89±0.03 at the start of the infection to 0.28±0.08μmol/l, 9 days post-infection (p.i.). Similarly, adreno-corticotrophic hormone levels were also observed to fall from 62.09±12.06 to 20.54±1.81 by 5 days p.i. and to 35.12±16.61 nmol/l by 9 days p.i. However, no significant changes were seen in the dry weight of the adrenal glands other than those expected in relation to changes in body weight. Concentrations of both plasma tri-iodothyronine and thyroxine were also severely depleted over the same period from 5.33±0.34 to 1.09±0.42 and 104.43±10.4 to 34.12±8.95 nmol/l respectively. This was considered not to be due to any change in the capacity of the plasma to bind these hormones. Results for insulin were highly variable, but overall were lower from protein-malnourished rats than results documented for well-nourished rats and a reduction from 18.07±3.17 to 6.08±2.18μunits/ml, 9 days p.i. was observed. The results are discussed in relation to the role of these hormones in protein metabolism in a protein-malnourished animal.
Destruction ofLeishmania mexicana amazonensis amastigotesby leucine methyl ester: protection by other amino acid esters
Authors: Alfieri Silvia C. , Zilberfarb V. , Rabinovitch M.
Published: June 2009

l-Amino acid esters, such as leucine methyl ester (Leu-OMe) can destroy intracellular as well as isolated amastigotesof Leishmania mexicana amazonensisby a mechanism which may involve ester hydrolysis by parasite enzymes. We show here that several other esters prevented the killing of the amastigotes by Leu-OMe. Destruction ofLeishmaniawithin macrophages in culture was assessed microscopically and viability of isolated parasites was monitored by reduction of the tetrazolium MTT. The main features of the protective effect were similar for intracellular and for isolated amastigotes. Thus, (i) effective prevention of parasite killing required that the protective ester be present in the medium prior to and during exposure of infected cells or parasites to Leu-OMe; (ii) the same esters protected intracellular and isolatedLeishmaniaagainst damage by Leu-OMe. Ranks of protective activity, as determined on isolated amastigotes were: Gly-OBz > Tyr-OMe > Ile-OMe > Met-OMe > Val-OMe > Ala-OMe > Gly-OMe > D-Leu-OMe; (iii) several esters were inactive in both systems (Leu-OBz, Trp-OMe and Phe-OMe). Protective activity was associated with leishmanicidal (e.g. Gly-OBz, Tyr-OMe) as well as with non-leishmanicidal (e.g. Ile-OMe, Val-OMe) esters. The results are compatible with the hypothesis that protective esters inhibit the activity of parasite enzyme(s) which hydrolyse Leu-OMe.
Analysis and comparison of immune reactivity in guinea-pigs immunized with equivalent numbers of normal or radiation-attenuated cercariae ofSchistosoma mansoni
Authors: Rogers M. V. , McLaren Diane J.
Published: June 2009

Guinea-pigs immunized with equivalent numbers of normal or radiation-attenuated cercariaeof Schistosomamansoniare known todevelop close to complete resistance to reinfection at weeks 12 and 4·5 respectively. We here analyse and compare the immune responses induced by the two populations of cercariae. Both radiation-attenuated and normal parasites ofS. mansonielicited an extensive germinal centre response in guinea-pigs by week 4·5 post-immunization. The anti-parasite antibody titre and cytotoxic activity of serum from 4·5-week-vaccinated, or 4·5-week-infected guinea-pigs were approximately equal, but sera from 12-week-infected individuals had high titres of anti-parasite antibody, which promoted significant larvicidal activityin vitro.In all cases, larvicidal activity was mediated by the IgG2 fraction of the immune serum. Lymphocyte transformation tests conducted on splenic lymphocytes from 4–5-week vaccinated guinea-pigs revealed maximal stimulation against cercarial, 2-week and 3-week worm antigens, whereas spleen cells from 4–5-week-infected guinea-pigs were maximally stimulated by cercarial and 6-week worm antigens. The splenic lymphocyte responses of 12-week infected animals were dramatic against antigens prepared from all life-stages of the parasite.
Inhibitory, opsonic and cytotoxic activities of monoclonal antibodies against asexual erythrocytic stages ofPlasmodium falciparum
Authors: Li J. L. , Li Y. J.
Published: June 2009

A 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

We 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

Of 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

A 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

Primary 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

The 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

The 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

L-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

Blatticola 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

The 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

The 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

The 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

Effects 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

The 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.
Comparison of glycolysis and glutaminolysis in Onchocerca volvulus and Brugia pahangi by 13C nuclear magnetic resonance spectroscopy
Authors: MacKenzie N. E. , Waa E. A. Van De , Gooley P. R. , Williams J. F. , Bennett J. L. , Bjorge S. M. , Baille T. A. , Geary T. G.
Published: June 2009

Comparison of glycolysis in Brugia pahangi and Onchocerca volvulus by C nuclear magnetic resonance (NMR) spectroscopy showed that the former organism is predominantly a lactate fermenter and the latter resembles more closely the metabolism of a mixed acid fermenter producing lactate, succinate, acetate, ethanol, formate and carbon dioxide. Both organisms synthesize glycogen as a storage carbohydrate. Glutaminolysis in both organisms proceeds by the δ-aminobutyrate shunt to produce succinate which is then further metabolized to acetate and carbon dioxide as end-products.
A monoclonal antibody against Echinococcus multilocularis Em2 antigen
Authors: Deplazes P. , Gottstein B.
Published: June 2009

A monoclonal antibody (MAb G11) species-specific to the Em2 antigen of Echinococcus multilocularis was generated for (i) further biological characterization of the Em2 antigen, (ii) easy affinity-purification of Em2 antigen for immunodiagnostic and immunological investigations and (iii) development of a sandwich-ELISA for the detection of Em2 antigen in diagnostic samples and thus species-specific identification of E. multilocularis metacestode material. The MAb G11 was used in an antibody sandwich-ELISA to detect soluble Em2 antigen with a methodical sensitivity of 80 ng E. multilocularis antigen/ml of solution. MAb G11 specifically detected Em2 antigen in all of 15 E. multilocularis-isolates originating from various geographical areas and in none of other helminth isolates (e.g. Echinococcus granulosus, E. vogeli, and others). Further biological analysis by FITC-labelled MAb G11 demonstrated unique binding activity to the laminated layer of the metacestode. Also, oncospheres were binding FITC-labelled MAb G11 on an outer layer synthesized during cultivation in vitro for 13 days after hatching. Application of the MAb G11 antibody sandwich-ELISA for investigation of solubilized oncospheres confirmed the in vitro synthesis of Em2 antigen by oncospheres on day 13 p.i. Adult stages (somatic antigens) and freshly hatched oncospheres were always MAb G11 negative. Solid-phase MAb G11 was used for purification of the corresponding Em2 antigen by affinity chromatography. A preliminary serological evaluation of the Em2(G11) antigen by ELISA revealed identical immunodiagnostic characteristics, compared to Em2 obtained by classical means, thus suggesting the presented method for future isolation of large-scale Em2 antigen.
On the possible schistosomulicidal effect of macrophage-derived lysozyme
Authors: Flescher E. , Keisari Y. , Lengy J. , Gold D.
Published: June 2009

Lysozyme secretion from macrophages ofSchistosoma mansoni-infected mice was time dependent, rising significantly from the 8th week post-infection, the macrophages thereafter exhibiting very high levels (> 90%) of schistosomulicidal activity. Despite the ability of lysozyme to kill schistosomulain vitro, the concentrations required for such killing were several hundred-fold to several thousand-fold higher than those detected in the supernatants from infected-mice macrophages cultured with or without schistosomula. Anin vitrolysozyme inhibitor,N, N, N-triacetyl chitobiose, did not abrogate the cytotoxic ability of macrophages from schistosome-infected mice, but an inhibitor of arginine-dependent cytotoxicity,NG-monomethyl arginine, markedly inhibited schistosomulicidal activity. Evidently, concentrations of ambient lysozyme from macrophage cultures are too low to affect schistosomula in culture, while the main schisto-somulicidal pathwayin vitroseems to be arginine dependent.
The adaptation of three isolates ofBabesia divergensto continuous culture in rat erythrocytes
Authors: Ben Musa N. , Phillips R. S.
Published: June 2009

Three isolates ofBabesia divergenshave been cultured continuously for 6 months in rat erythrocytes using the candle jar technique (Trager & Jensen, 1976). One isolate was already rat-adapted, the other two became adapted to rats through continuous culture in rat erythrocytes. Parasites were cultured in rat erythrocytes in RPMI medium supplemented with 20% foetal calf serum. The highest parasitaemia obtained was 35% and multiparasitization of red blood cells was often observed. Cultures ofB. divergensremained infective to splenectomized rats. Cultures with high parasitaemias contained a large number of extracellular merozoites. When separated from the red blood cells, these extracellular merozoites retained their infectivity.
Histological examination of the cellular reactions around schistosomula ofSchistosoma mansoniin the lungs of sublethally irradiated and unirradiated, immune and control rats
Authors: Vignali Dario A. A. , Klaus S. N. , Bickle Q. D. , Taylor M. G.
Published: June 2009

Histopathological data on the cellular reactions (foci) aroundSchistosoma mansonischistosomula in the lungs of both irradiated (750 rad) and unirradiated, passively immunized and normal rats were consistent with the idea that a significant proportion of immune-mediated attrition in passively immunized rats occurs in the lungs. In unirradiated rats, immune serum elicited an enhanced (i.e. larger) and accelerated (i.e. more rapidly developing) inflammatory cellular infiltration around lung-stage parasites when administered 5 days post-infection, when the parasites were already in the lungs. This demonstrated the antigenicity of lung-stage schistosomula and their potential as targets for immune attack. In irradiated rats, innate immunity was decreased as judged by an increase in the number of worms recovered by portal perfusion, and was accompanied by an overall decreased percentage of trapped parasites compared with unirradiated controls, suggesting that trapping in the lungs is involved in innate, as well as acquired immunity. In contrast to the results in unirradiated rats, passive transfer of immune serum into irradiated recipients did not result in larger lung foci than in the NRS-recipients. However, there was evidence of an accelerated response resulting in an essentially similar ratio of trapped parasites (VRS- compared with NRS-recipients) in irradiated rats, as compared with unirradiated rats, reflecting the similar levels of resistance manifested in both groups of rats. This also lent credence to the notion that it was thespeedof immune recognition of the migrating schistosomula and the establishment of trapping foci that were of greater importance rather than thesizeof the enveloping granulomata. Investigations into the cellular composition of the foci surrounding trapped parasites in unirradiated rats revealed a predominance of mononuclear cells, with equal proportions of lymphocytes and macrophages. Eosinophils represented less than 3% of the cellular composition of the foci and were typically distant from the parasites themselves, arguing against their role in specific immunity in this model. Irradiation of recipient rats resulted in a corresponding increase in the percentage of macrophages in lung foci.
An ELISA for the detection of pentastomid infections in the rat
Authors: Jones D. A. C. , Riley J.
Published: June 2009

A specific enzyme-linked immunosorbent assay, based on a 48 kDa metallo-proteinase isolated from the frontal glands of a porocephalid pentastomid (Porocephalus crotali) in rat intermediate hosts, is described. SDS–PAGE analysis of whole nymphal homogenate, followed by Western blotting and probing with immune rat serum, revealed that only 2 protein bands label consistently; these are the 48 kDa metallo-proteinase and a 150 kDa metallo-proteinase from the body fluid, but only the former labels strongly. Furthermore this response is detected earlier and persists much longer. These characteristics uniquely qualify the 48 kDa metallo-proteinase as a diagnostic antigen. We review the literature concerning the related porocephalid Linguatula serrata from the nasal cavities of domestic dogs, which can zoonotically infect man principally through the ingestion of eggs. We conclude that the high prevalences in dogs in certain areas, most notably the Middle East, must inevitably signal significant human infections. Our ELISA can be readily adapted for the serodiagnosis of linguatulosis and this should establish whether our prediction is true.
Trichinella pseudospiralisovercomes innate resistance of the chinese hamster toTrichinella spiralis
Authors: Larsen E. , Stewart G. L. , Niederkorn J. Y.
Published: June 2009

Infectivity ofTrichinella pseudospiralisin Chinese hamsters was greater than that ofTrichinella spiralis. Concurrent infection with these two species of parasite was accompanied by an increase in infectivity ofT. spiralis. The infectivity ofT. pseudospiralis, but not that ofT. spiralis, was significantly influenced by host age. Regardless of host age,T. pseudospiraliswas more infective for the Chinese hamster than wasT. spiralis. Early during infection, enteritis (myeloperoxidase activity) in hamsters infected withT. pseudospiralisalone was significantly less than that seen in animals infected withT. spiralisalone or with both species concurrently. Myositis in hamsters infected withT. pseudospiralisalone was significantly less on days 14, 17 and 25 post-infection (p.i.) than that observed in concurrently infected orT. spiralis-infected animals. On days 11 and 14 p.i. inflammation in diaphragm muscle from concurrently infected hamsters was significantly less than that seen in animals infected withT. spiralisalone. Muscle histology supported these chemical data on myositis. Suppression of the host inflammatory response against early muscle-stage larvae ofT. pseudospiralisunderlies the greater infectivity of this parasite for the Chinese hamster.
Survival, strobilation and sexual maturation of Echinococcus multilocularis in the small intestine of golden hamsters
Authors: Kamiya M. , Sato H.
Published: June 2009

Echinococcus multilocularis survived, strobilated and matured sexually in the small intestine of 6-week-old male golden hamsters that were either non-treated or treated with prednisolone tertiary-butylacetate (PTBA), following oral administration of 20000 protoscoleces. Non-treated hamsters harboured the adult worms for up to 25 days post-infection (p.i.). Hamsters treated with PTBA from the day of infection (day 0 p.i.) harboured more adults than the non-treated, and their survival periods were extended. Moreover, a remarkable improvement in worm recovery, development and survival periods was observed in hamsters additionally treated with PTBA on days — 14 and — 12 p.i., and the worm development including proglottisation, sexual maturation and egg formation was comparable with that in dogs. With the present results it is suggested that Echinococcus/rodent systems represented by the E. multilocularis/golden hamsters may rejuvenate the current stagnant research on host-parasite interactions of the definitive host-stage and egg-stage of Echinococcus.
Effect of acute phase proteins, especially α2-macroglobulin, on granuloma formation aroundSchistosoma mansonieggs in the rat
Authors: Van Gool J. , Van Tiel D. , Doenhoff M. J. , Van Vugt H.
Published: June 2009

A new model for the study of granuloma formation in the liver is described. Rats received an injection of 20 000Schistosoma mansonieggs in the portal vein and granuloma formation was evaluated at 3, 5 and 7 weeks post-injection. Liver collagen was estimated at the same time and serum procollagen III peptide, a marker of collagenesis, weekly. With this model, wherein the number ofS. mansonieggs and the time of injury are standardized, the effect of high levels of acute phase proteins especially α2-macroglobulin on granuloma formation was studied. It appeared that in rats with high levels of α2-macroglobulin the mean size of granulomas was significantly greater at 3 and 5 weeks compared with controls. In both groups an increase in liver collagen was observed during this period, reaching a peak at 5 weeks in the acute phase group. This model facilitates the study of the effects ofS. mansonieggs on granuloma formation.