bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lysosomes and tegument pathology in the chemotherapy of schistosomiasis with 1,7 -bis(p-aminophenoxy)heptane(153C51)
Authors: Watts S. D. M. , Orpin A. , MacCormick C. 
Published: June 2009

SUMMARYOne therapeutic oral dose (400 mg/kg) of 153C51 administered to infested mice caused pathological changes in the dorsal region of the tegument of maleSchistosoma mansoniduring the period 3–24 h after treatment. These changes occurred prior to the ‘hepatic shift’. At the ultrastructural level they consisted of a gradual accumulation in the tegument epidermis of numerous membranous inclusions with the characteristics of residual lysosomes and changes in the localization of acid phosphatase, a lysosomal enzyme. It seemed likely that these changes were due to inhibition or exhaustion of enzyme in the epidermis, followed by re-synthesis of enzyme in the cell bodies and its export to the epidermis. The elimination of hydrolytic activity from lysosomes in the epidermis would explain the accumulation of residual lysosomes. Drug- treated parasites retained their disguise of host red blood cell ghost antigens as shown by indirect fluorescent antibody-labelling and, therefore, it seemed unlikely that immunological factors could be important in producing the tegument pathology.
Cross-immunity to Schistosoma mansoni and S. haematobium in the hamster
Authors: Smith M. A. , Clegg J. A. , Webbe G. 
Published: June 2009

SummaryHamsters (WO strain) with a primary infection of Schistosoma mansoni or S. haematobium rapidly developed immunity to homologous challenge judged by the lung recovery assay. Immunity was detected at 4–5 weeks and reached a plateau 6 weeks after infection.Using this information, hamsters with an 8-week primary infection with S. mansoni or S. haematobium were tested for resistance to homologous reinfection and resistance to a challenge with the other species of schistosome. Primary infection with S. mansoni or S. haematobium conferred a high level of immunity to reinfection with either species of schistosome judged by the perfusion assay, involving recovery of adult worms 6–10 weeks following challenge. Estimation of the level of immunity with the lung recovery assay, 5 days after challenge, indicated that immunity due to a primary infection with S.mansoni acted at or before migration of the challenge through the lungs but immunity stimulated by a primary S. haematobium infection was only partially effective at the lung stage and substantial destruction of challenging organisms occurred at a later stage of development.Antibodies in immune sera of hamsters with a primary S. mansoni or S. haematobium infection were shown to bind to common antigens on the surface of young schistosomula of either species by u.v. microscopy using as detecting agent a fluorescein-labelled rabbit antiserum directed against hamster globulins.
Molecular structure and morphology of glycogen isolated from the cestode,Moniezia expansa
Authors: Orpin C. G. , Huskisson N. S. , Ward P. F. V. 
Published: June 2009

SummaryA particulate polysaccharide was isolated by differential centrifugation and alkali extraction from homogenates of the cestodeMoniezia expansa. The polysaccharide had the structure of a glycogen. Its chemical properties, infra-red spectrum and optical rotation showed that it consisted of α-1, 4- and α-1, 6-linked glucopyranose units. Examination of the complex with iodine and the precipitate with concanavalin-A showed that the structure was highly branched. Oxidation with periodate and hydrolysis with α- and β-amylase were used to measure mean chain lengths. For the particulate preparation the average chain length was 12·9 glucose units and the exterior and interior chain lengths were 9·0 and 2·9 units respectively. The particulate preparation had a very high sedimentation constant (s20, w= 910) with a smaller component at abouts20, w= 600, but the alkali extracted material had ans20, w= 61 similar to that shown by alkali degradation of the particulate preparation. The morphology of the particulate material was similar to that of rat liver glycoge, α, β- and possible γ-particles being identified by electron microscopy. The α-particles were relatively stable under acidic conditions remaining intact down to pH 2·5. At pH 1·7 the α-particles dissociated into their constituent β-particles with a consequent decrease in the opalescence of the solution. The nitrogen content of 0·9% was high for a glycogen.
Factors affecting the acquisition of resistance against Schistosoma mansoni in the mouse. Evidence that the mechanisms which mediate resistance during early patent infections may lack immunological specificity
Authors: Harrison R. A. , Bickle Q. , Doenhoff M. J. 
Published: June 2009

SUMMARYMice infected with 25 to 35 unsexed Schistosoma mansoni cercariae became resistant to homologous challenge by 8 weeks, and the degree of resistance that was acquired correlated with the size of the worm burden and the tissue egg burden. Mice given 100 male or 100 female cercariae alone failed to become resistant even after 30–40 weeks of infection. When a super-infection of 100 male or 100–300 female cercariae was given to mice with 25 unsexed cercariae, the degree of resistance that was acquired was generally lower than in mice given 25 unsexed cercariae alone. In the super-infected mice there was no correlation between the size of the worm burden (mainly unpaired male or female worms) and the degree of acquired resistance. In mice super-infected with male worms there was an inverse correlation between the number of male worms and the number of eggs deposited in the liver and intestine by each mature worm pair. A positive correlation was, however, still found between the degree of acquired resistance and total tissue egg counts in mice super-infected with single sex cercariae. Mice injected intraperitoneally or subcutaneously with intact S. mansoni eggs failed to become resistant to S. mansoni challenge. Transfer of lymphoid cells or serum, separately or together, from heavily infected and demonstrably resistant donor mice to naive normal or T-cell deprived recipients failed to render the recipients resistant to S. mansoni challenge. The results indicate that resistance to re-infection in mice with recently patent S. mansoni infections is dependent on the number of S. mansoni eggs entrapped in the tissues, and that excessive numbers of unpaired S. mansoni male or female worms can inhibit the fecundity of established worm pairs. The apparent acquired resistance to S. mansoni that has been observed in this model system may be largely a consequence of non-specific factors interfering with normal patterns of challenge worm migration and maturation.
The diurnal migration of the fowl cestode, Raillietina cesticillus
Authors: Gray J. S. 
Published: June 2009

SummaryR. cesticillus was found to undergo a diurnal migration in both multiple and single worm infections of the fowl. This migration involved movement of both scoleces and strobilae and occurred in an anterior direction when the intestine was empty of food, and in a posterior direction when the intestine contained food. The relevance of the migration to the histological picture of the worm in situ is discussed and some possible explanations for the migration are suggested.
A comparative analysis of various developmental stages ofSchistosoma mansoniwith respect to their protein composition
Authors: Ruppel Andreas , Cioli Donato 
Published: June 2009

SummaryThe protein composition ofSchistosoma mansoniwas analysed by electrophoresis in polyacrylamide slab gels in the presence of sodium dodecyl sulphate. A high degree of identity existed between protein patterns obtained from immature and adult parasites of the two sexes. Some stage-and sex-specific components were identified and their possible origin discussed.
The structure and formation of the egg-shell of Hammerschmidtiella diesingi Hammerschmidt (Nematoda: Oxyuroidea)
Authors: Wharton D. A. 
Published: June 2009

SUMMARYThe structure and chemistry of the egg-shell of Hammerschmidtiella diesingi was examined. The shell consists of 5 layers: external uterine layer, internal uterine layer, vitelline layer, chitinous layer and lipid layer. The uterine layers contain discrete spaces which open to the exterior via pores. Freeze etching revealed particles of 8·0 nm diameter in the external uterine layer and fibres measuring 2·6–3·1 nm in the chitinous layer. The morphology of the reproductive system, the cytoplasmic inclusions of the mature oocyte and the formation of the layers of the egg-shell are described.
The effect of age, acquired resistance, pregnancy and lactation on some reactions of cattle to infection with Ostertagia ostertagi
Authors: Michel J. F. , Lancaster M. B. , Hong C. 
Published: June 2009

SUMMARYAn experiment is described in which the effects of age, previous infection, pregnancy and lactation on some reactions of cattle to infection with Ostertagia ostertagi were studied. It was found that an acquired resistance to the establishment of worms developed more rapidly in 20-month-old heifers than in calves, that it was unaffected by pregnancy of the host but that it was largely lost by heifers in early lactation. The rate at which populations were turned over, i.e. the mean life-span of worms through the late 4th and 5th stages was unaffected by the factors studied. Although, in the conditions of the experiment, development of the worms was not arrested in susceptible calves, both age of the host and its previous experience of infection were significant causes of arrest, and in previously infected 20-month-old cattle 86% of the worms of a challenge infection were arrested. Pregnancy did not affect the proportion of worms that was arrested but in lactating heifers only marginally more worms were arrested than in calves. Worms that were not arrested grew more rapidly in calves and in lactating heifers than in empty heifers or those in mid-pregnancy.
Growth of Trypanosoma cruzi in vitro: development and application of a continuous-flow culture system
Authors: Williams G. T. , Hudson L. 
Published: June 2009

SummaryThe design and operation of a modular, bacteriological continuous-flow culture system have been adapted for the growth of Trypanosoma cruzi epimastigotes in simple monophasic media. The system was designed to achieve a minimum of 200 days of continuous culture and provision was made for the continuous supply of medium and collection of parasites under sterile conditions. The system provides large quantities of epimastigotes with homogeneous morphology and uniform viability. The system also lends itself tothe analysis of the factors which affect parasite growth. We have examined the effects of changes in environmental parameters on epimastigote growth rate. Optimal growth was observed at 27 °C. The rate ofstirring of the culture had a small but definable effect on the growth rate, which was greatest at 80 r.p.m. Growth was only slightly affected by the level of dissolved oxygen between 10 and 50% saturation, but was inhibited at higher concentrations. Growth was slower at extreme values of pH but showed a broad optimum around pH 7·4.
Cryopreservation of Babesia bovis for in vitro cultivation
Authors: Palmer D. A. , Buening G. M. , Carson C. A. 
Published: June 2009

SummaryThe most efficient procedure for cryopreserving viable Babesia bovis organisms for in vitro cultivation consists of freezing extracellular parasites in a solution of 10% (w/v) polyvinylpyrrolidone (PVP) using a cooling rate of 20 °C/min. Although cultures can be established from thawed infected erythrocytes, the plating efficiency is relatively low. Freezing extracellular parasites resulted in plating efficiency up to 25%, when thawed and placed in culture. Glycerin or dimethyl sulphoxide (Me2SO) can be used successfully in the cryopreservation of B. bovis, but apparent toxic effects greatly decrease their efficiency. B. bovis parasites have been kept at − 196 °C for 60 days with no appreciable reduction in plating efficiency.
The dynamics of infection of Tribolium confusum by Hymenolepis diminuta: the influence of infective-stage density and spatial distribution
Authors: Keymer Anne E. , Anderson R. M. 
Published: June 2009

SUMMARYThe mean parasite burden of a population of Tribolium confusum is shown to rise to a plateau as the exposure density of infective eggs of Hymenolepis diminuta increases. The level of this plateau is shown to be dependent on the nutritional status of the host population, being depressed from approximately 18 cysticercoids/beetle in hosts which have been starved prior to experimentation, to approximately 2 cysticercoids/beetle in satiated hosts. A simple model is used to describe the shape of this infection functional response in terms of the predator–prey interaction between hosts (T. confusum) and parasite infective stages (H. diminuta eggs). The distribution of successful infections/host is shown to be over-dispersed, even when hosts are exposed to infective stages arranged in a uniform spatial pattern. The over-dispersion of parasite numbers/host is shown to become more severe as the spatial pattern of infective stages changes from under-dispersed, through random, to over-dispersed. Experimental results are discussed in relation to the dynamics of parasite–host interactions, in which infection takes place by host ingestion of a free-living infective stage.
Symposia Of The British Society For Parasitology
Authors: Anderson R. M. , Canning Elizabeth U. , Taylor Angela E. R. , Muller R. 
Published: June 2009

SUMMARYThe 1981 Autumn Symposium (held at the Zoological Society, London, on 31 October) was a new departure for the British Society for Parasitology in that Cambridge University Press have taken over publication of the proceedings. The style and layout of the contributions have been changed in order to conform with the format currently used in the journal Parasitology. The symposia proceedings will now be published as separate issues of Parasitology but with their own distinctive colour and cover design. The proceedings will be available by subscription to the journal or separately. Furthermore, the meeting organizers will in future be responsible for editing the symposia: assistance will be by Drs Taylor and Muller during a transition period.
Immunological differences in Eimeria maxima: effect of a mixed immunizing inoculum on heterologous challenge
Authors: Long P. L. , Millard B. J. 
Published: June 2009

SUMMARYThe immunological differences known to exist between laboratory strains of Eimeria maxima was confirmed. Protection against challenge with different strains or field isolates of the species could be achieved by including small numbers (25 oocysts) of each in the immunizing inoculum. Similar protection was obtained when 4 distinct populations which were allowed to interbreed were used in the immunizing inoculum. This hybrid mixture of E. maxima was used to immunize chickens against challenge with 7 new isolates of E. maxima from poultry houses in different parts of England. The results show that although immunological differences exist within E. maxima good protection against many strains of this species may be achieved by initial infection with the hybrid mixture of E. maxima.
Surface antigens of and cross-protection between two geographical isolates ofSchistosoma mansoni
Authors: Hackett F. , Simpson A. J. G. , Omer-Ali P. , Smithers S. R. 
Published: June 2009

SUMMARYTwo isolates ofSchistosoma mansonifrom Puerto Rico and Egypt were examined to determine if there were differences in surface antigens of the schistosomulum and to assess the ability of the two isolates to induce protection against one anotherin vivo. Immune mouse and human patient antisera recognized the same antigens on the schistosomulum surface of both isolates. However, mice immunized with schistosomula-released products from the Egyptian isolate recognized an additional antigen ofMr13K on the Egyptian schistosomulum surface which was not present in the Puerto Rican isolate. In quantitative radioimmunoassay, sera from mice vaccinated with irradiated Egyptian cercariae bound more strongly to Egyptian schistosomula than to Puerto Rican parasites. Both isolates cross-protected against each other, but mice were less immune to challenge with Egyptian cercariae after being immunized with Puerto Rican irradiated cercariae. There was no difference in immunity to challenge when Egyptian irradiated cercariae were used to immunize. Although this evidence suggested some heterogeneity within the Egyptian isolate, cloned cercariae of the Egyptian isolate did not vary in their ability to cross-protect against each other. Furthermore, antisera from mice immunized with clones of Egyptian cercariae recognized the same schistosomulum surface antigens. The results reported here indicate that although there were small differences between the two isolates the major surface antigens are conserved.
Echinococcus granulosus: changes in the surface ultrastructure during protoscolex formation
Authors: Rogan M. T. , Richards K. Sylvia 
Published: June 2009

SUMMARYChanges in the tegumentary projections of protoscoleces ofEchinococcus granulosus, developing within brood capsules, were examined at the ultrastructural level. The original scant covering of spineless, truncated microtriches was supplemented by a population of microvilli covering the entire surface of protoscoleces in the early stages of formation. As differentiation continued, rostellar hooks were formed by enlargement of single large (T1) microtriches, and normal spined microtriches were produced on the sucker region. These were formed in two ways: by addition of spine material to the truncated microtriches, andde novofollowed by up-lifting from the tegumentary surface. A second type of large microthrix (T2) was present in a band immediately below the developing hooks. These microtriches appeared to be formed from a fusion of existing microtriches, but were subsequently lost prior to scolex invagination. The microvilli were also shed from both the sucker and soma regions, to be replaced by microtriches and small blunt elevations respectively.
Interactions between the intestinal flagellates Giardia muris and Spironucleus muris and the blood parasites Babesia microti, Plasmodium yoelii and Plasmodium berghei in mice
Authors: Brett Sara J. , Cox F. E. G. 
Published: June 2009

SUMMARYIn mice infected with the intestinal flagellates Giardia muris or Spironucleus muris, together with the blood parasites Babesia microti or Plasmodium yoelii, there is a temporary decrease of flagellate cyst output coincident with the peak of the blood parasite infections, followed by a rapid return to normal levels. This decrease in cyst output is correlated with decreased numbers of trophozoites in the small intestine. The effect on S. muris is more marked than that on G. muris. Neither blood parasites has any effect on the total duration of the flagellate infection and the flagellates do not affect the blood parasites. In mice infected with G. muris or S. muris and P. berghei there is also a decrease in cyst output but this is less apparent than in infections with B. microti or P. yoelii because of the fatal nature of the P. berghei infection. It is suggested that the decrease in cyst output is probably due to changes in the contents of the small intestine or to non-specific immunological factors rather than to specific immunological changes.
Immunological comparison of four Trypanosoma spp. (sub-genus Schizotrypanum) from bats
Authors: Bower Susan M. , Woo P. T. K. 
Published: June 2009

SUMMARYThe antigenic differences and similarities between culture forms of Trypanosoma (Schizotrypanum) hedricki, Trypanosoma (Schizotrypanum) myoti, Trypanosoma (Schizotrypanum) vespertilionis and Trypanosoma (Schizotrypanum) dionisii, all isolated from bats, were compared using the double-diffusion technique. Antiserum to each trypanosome species was produced in rabbits by inoculating them with sonicated culture forms. Two isolates of T. hedricki were antigenically identical to each other, as were 2 isolates of T. myoti. There were several common antigens between the species. However, at least 1 antigen of each species was distinct from those of the other species.
Non-specific immunodepression by larval and adult Nematospiroides dubius
Authors: Ali N. M. H. , Behnke J. M. 
Published: June 2009

SUMMARYMice infected with Nematospiroides dubius generate weaker immune responses to concurrently administered sheep red blood cells (SRBC), than non-infected controls. The experiments described in this paper demonstrate that both adult and larval stages of N. dubius cause non-specific immunodepression of the response to SRBC. Mice which had been infected with larvae exposed to 25 krad. of irradiation, which prevents development to the adult luminal stages, produced as weak haemagglutination responses to SRBC as mice infected with normal worms even when SRBC were administered 6 weeks after infection. The removal of adult N. dubius by treatment with pyrantel 9, 11 and 15 days after infection with normal larvae did not restore the host's ability to respond to SRBC given on day 14. It was only when the mice had been without worms for 17 days that their capacity to respond normally to SRBC was restored. Mice infected with 60 or 400 transplanted adult worms produced depressed haemagglutination and plaque-forming responses to concurrently injected SRBC when compared with normal or sham-operated controls. The significance of these results is discussed in relation to the possible role of non-specific immunodepression in facilitating the survival of N. dubius in the host.
Development of early larval stages of Taenia ovis in vitro using a cell monolayer
Authors: Lawrence S. B. , Heath D. D. , Parmeter S. N. , Osborn P. J. 
Published: June 2009

SUMMARYAn in vitro culture system incorporating a cell monolayer was used to induce most activated oncospheres of Taenia ovis to enter post-oncospheral development. Seven distinct developmental phases were recognized during the 23 days required for development to reach a stage similar to that achieved after 14 days in vivo. Secretions or tegumental substance were released during each developmental phase.
Temperature-dependent survival and reproduction within populations of the ectoparasitic digenean Transversotrema patialense on the fish host
Authors: Mills C. A. 
Published: June 2009

SUMMARYThe reproduction and survival of the ectoparasitic digenean Transversotrema patialense on the fish host Brachydanio rerio are shown to be temperature-dependent. Survival is reduced by any deviation from an optimum temperature of approximately 23°C. With increasing temperature the rate of egg production per surviving fluke rises progressively faster to a higher peak up to 29°C but falls to zero by 35°C. The span of egg production varies closely with the life-span of the parasite at each temperature. The optimum temperature for the total number of eggs produced by each cohort of parasites is also 23°C. This number is a function of both adult parasite survival and the rate of egg output.