bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative electron microscope studies on the epidermis of the blood living juvenile and gill living adult stages of Amphibdella flavolineata (Monogenea) from the electric ray Torpedo nobiliana
Authors: Lyons Kathleen M. 
Published: June 2009

SUMMARYThe covering layer of Amphibdella flavolineata has been found to be a syncytial cytoplasmic epidermis bearing scattered microvilli and connecting with parenchymally situated ‘cell’ bodies or cytons by means of conspicuous, microtubulelined cell processes. There was no evidence from a comparison of the covering epidermis of the juvenile blood living form and that of the gill living adult that this layer in the juvenile was especially modified for life in the host blood system.The epidermis of adult and juvenile worms was found to be remarkably similar, the main difference being that that of the adult was slightly thicker and bears longer microvilli. Apart from some lamellate bodies of doubtful significance, the inclusions found in the epidermis of adult and juvenile forms were also very similar.The outer epidermis of the juvenile monogenean was found to be quite different from that of Schistosoma mansoni in that it is not permeated by incursive channels and contains many more mitochondria than the epidermis of the digenean. The epidermal cell bodies of Amphibdella tend to have electron-lucent areas especially in the ‘ apical cell’ regions leading to the cell processes that connect with the outer layer. Electron-dense granules secreted by the epidermal cells accumulate in these ‘clear’ regions before being transferred to the outer layer. There is some slight evidence that these electron-lucent regions may have contained glycogen. The epidermal ‘cell’ bodies of the juvenile tend to be multinucleate, whilst those of the adult are usually uninucleate.Thanks are due to the Director and staff of the Marine Biological Laboratory, Plymouth for providing accommodation and material. The assistance of Mr George Best of the Plymouth Laboratory and Mr Harry Edge of King's College London Botany Department, who maintain the microscopes used in this work, is especially appreciated.
A comparison of multiplication rates in primary and challenge infections ofTrypanosoma bruceibloodstream forms
Authors: McLintock L. M. L. , Turner C. M. R. , Vickerman K. 
Published: June 2009

SUMMARYThe hypothesis that division ofTrypanosoma bruceislender bloodstream forms is dependent upon the availability of a host-derived growth factor has been tested by superimposing challenge doses of slender-form trypanosomes onto preexisting infections at a time during the primary infection when stumpy forms predominated. The challenge populations grew in the doubly-infected mice indicating that depletion of a putative growth factor by the expanding population of the primary infection had not prevented division of the trypanosomes although slight reductions in multiplication rates were observed. This effect was independent of the variable antigen type (VAT) of the trypanosomes and of their stock of origin.
Hymenolepis diminuta: changes in intestinal morphology and the enterochromaffin cell population associated with infection in male C57 mice
Authors: Mckay D. M. , Halton D. W. , Johnston C. F. , Fairweather I. , Shaw C. 
Published: June 2009

SUMMARYMean villus height, crypt depth and the number of 5-HT-positive enterochromaffin (EC) cells have been examined in two regions of the small intestine (20–30° and 60–70° distance from the pylorus) of male, 6 to 8-week-old, C57 mice following a 5-cysticercoid infection of the rat tapeworm,Hymenolepis diminuta. Test mice and sham-infected controls were autopsied 0, 4, 8, 10, 14 and 28 days post-primary infection (p-1°-i) and 2, 4, 5, 7 and 14 days post-secondary infection (p-2°-i), administered 28 days p-1°-i. Morphometric analysis revealed a statistically significant increase in crypt depth in the 60–70°ointestine region in infected mice during both primary and secondary infections; no significant deviation from the control was observed for villus height in infected mice. Statistical analysis showed a significant increase in the number of 5-HT-positive EC cells in infected mice. This response occurred in the lower portion of the intestine on days 10-p-1°-i and 5-p-2°-i, and was not due to increased mucosal surface area in this region. Results are discussed with reference to murine cestode rejection and the possible involvement therein of the neuroendocrine system.
Population dynamics in echinococcosis and cysticercosis: regulation ofTaenia hydatigenaandT. ovisin lambs through passively transferred immunity
Authors: Gemmell M. A. , Lawson J. R. , Roberts M. G. , Griffin J. F. T. 
Published: June 2009

SUMMARYA comparison has been made of the interactions between passively transferred and actively acquired immunity in regulating populations ofTaenia hydatigenaandT. ovis.When ewes were grazed prior to parturition under a high infection pressure, immunity was transferred to their offspring for up to 8 weeks. A qualititative difference between the species was the destruction of larvalT. ovisprior to their establishment (‘pre-encystment immunity’) and that ofT. hydatigenaafter they had become established (‘post-encystment immunity’) in the challenged lambs. The major difference in terms of population regulation between the two parasites was that infection occurred withT. hydatigenabut not withT. ovisin those lambs reared from birth for 16 weeks under high infection pressure. Passive, like active immunity, is a density-dependent constraint. It plays an important role in the population regulation ofT. ovis, but not ofT. hydatigena. This is discussed in terms of transmission in the natural environment, an hypothesis on humoral protection and the need to elucidate pathways of protection when immunization schedules are being evaluated for controlling the taeniid zoonoses.
Differences in the parasite infections in three-spined sticklebacks (Gasterosteus aculeatusL.) of different sex, age and size
Authors: Pennycuick Linda 
Published: June 2009

A population ofGasterosteus aculeatusfrom Priddy pool in Somerset was infected with three species of parasites:Schistocephalus solidus,Diplostomum gasterosteiandEchinorhynchus clavula.The variations in the incidence and intensity of the infections with the sex, age and size of the sticklebacks are described.The infections with the three parasites were very similar in male and female sticklebacks. The weights ofSchistocephaluswere greater in the females, however;the mean weight of the plerocercoids was larger suggesting that they grew more rapidly in female fish.TheSchistocephalusinfection increased in small fish, under 1 year of age, but in older larger ones the infection decreased. These changes can be related both to the feeding habits of the fish and to the weight relationships of host and parasite.It was found that the weight ofSchistocephalusdid not greatly exceed that of the fish, and also that the combined weight of fish plusSchistocephaluswas rarely greater than 3 g. Therefore the proportional weight ofSchistocephalus, or parasite index, was lower in sticklebacks heavier than about 1·5 g.TheDiplostomumandEchinorhynchusinfections both increased with age and size of fish, but the largest sticklebacks were not the most heavily infected. These increases can be related to the feeding habits of the fish in the case ofEchinorhynchusand to accumulation with time in the case ofDiplostomum.In all three species the largest and oldest fish were not the most heavily infected.It is suggested that the old fish are becoming senile and are therefore less able to support large parasite burdens.I am very grateful to Dr H. D. Crofton for his constant advice and encouragement during this study, and to Dr R. A. Avery for useful discussions. This work was supported by a Science Research Council research studentship and by a NATO studentship.
The biology of Clavella uncinata (Muller) (Crustacea: Copepoda)
Authors: Shotter R. A. 
Published: June 2009

Clavella uncinata (Muller) (Crustacea: copepoda) was found infesting 24% of 1352 whiting Odontogadus merlangus (L.) examined from the North Irish sea.A study of the dimensions of the adult female and a comparison of the morphology of copepodid larvae from the Clavella of whiting and pollack Pollachius pollachius (L.) suggests that the Clavella from these gadoids are all one species. Observations on the process of feeding and histochemical analysis of the gut contents indicate that the parasites feed by browsing on the superficial tissues of the whiting and that the mouthparts are used more for the gathering of food towards the mouth than for cutting. Observations show that the hatching of eggs and the behaviour of the nauplii are remarkably similar to these functions in free-living copepods. Examination of Clavella from adult and young whiting, and from living specimens kept alive on the fish, suggests that there are definite cycles of development, that the eggs take about 21 days to mature and that adult Clavella has a life span of no more than 6 months.I would like to thank the Masters and crews of the R.V. Cuma and R.V. Silver Spray and the staff of the Marine Biological Station, Port Erin for their help in the collection of material. I am especially grateful to Mr D. J. Slinn who guided me throughout this work and to Mr R. Moore for his technical assistance.
The structure and development of the protozoonHistomonas meleagridisin the male reproductive tract of its intermediate host,Heterakis gallinarum(Nematoda)
Authors: Lee D. L. 
Published: June 2009

The ultrastructure and development ofHistomonas meleagridisin the reproductive tract of maleHeterakis gallinarumhas been described. In the testis the protozoon is a relatively large amoeboid organism which lies between the epithelial cells of the testis and the spermatogonia, spermatocytes and spermatids. It is similar in appearance to the invasive stage which is found in the final host and like the invasive stage, it also feeds upon the host cells by phagocytosis. In the vas deferens the protozoon lies between the host cells, where it is much smaller than the stages in the testis but still amoeboid, and inside the cells of the vas deferens.Intracellular stages are much smaller than the other stages, are rounded in appearance and cause little or no damage to the host cell. They are similar to the stages found in oocytes of the female nematode. The possible role of the male nematode in the life cycle of the protozoon is discussed.I wish to thank Mrs B. Fisher for technical assistance and Mr B. Carter for assistance with the photography.
An artificial feeding technique for Glossina
Authors: Moloo S. K. 
Published: June 2009

An apparatus for the artificial feeding of tsetse has been described. Fresh defibrinated blood at 36 °C is circulated with a peristaltic pump through feeding capsules. The efficiency of the method has been compared with that of the Cockings' method and with the live host feeding. The flies exposed to feeding on this apparatus showed significantly higher feeding frequency than those allowed to feed on the Cockings' apparatus. Compared with the live host feeding, the feeding frequency for circulating blood method was slightly lower but the difference was not significant. Once the fly is induced to feed, it would in most cases complete engorgement unless disturbed. The rate of crop emptying in flies fed by the Cockings' method was abnormally slower as compared to those fed on the circulating blood. The present study indicates that for the successful artificial feeding of tsetse, it is essential to circulate the blood and regulate the temperature of the medium and the feeding surface to approximately 36 °C.I wish to thank Mr S. B. Kutuza for technical help, and the Director of E.A.T.R.O. for permission to publish this work.
Trypanosoma congolense: the distribution of enzymic variants in East and West Africa
Authors: Gashumba J. K. , Baker Rose D. , Godfrey D. G. 
Published: June 2009

SUMMARYA total of 114 stocks of Trypanosoma congolense originating from Kenya, Uganda, Tanzania, Zambia and Sudan, but including, for comparison, stocks from The Gambia, Liberia, Ivory Coast, Nigeria and Cameroun, were compared by isoenzyme electrophoresis for 6 enzymes. The zymodemes were grouped, both from a dendrogram and using a cladistic method, after calculating the dissimilarity, or distance, between profiles. Previous observations are broadly confirmed, the zymodemes clustering separately according to geographical origin and ecological zone. Thus, one group was composed almost entirely of East African stocks, and another of stocks from both East and West Africa, although each group was of savanna origin. A third group was composed of stocks from the humid, rain-forest zones of West Africa, and was particularly characterized by isoenzyme variants of superoxide dismutase and glucose-phosphate isomerase. Two stocks from the Kenyan coast formed a markedly separate group, which may be taxonomically distinct.
Patterns in helminth communities in freshwater fish in Great Britain: alternative strategies for colonization
Authors: Esch G. W. , Kennedy C. R. , Bush A. O. , Aho J. M. 
Published: June 2009

SUMMARYExamples of the apparently stochastic nature of freshwater fish helminth communities illustrating the erratic and unpredictable occurrence and distribution of many species are provided for six species of fish from several localities throughout Britain. By focussing on parasite colonization strategies two categories of helminths are recognized: autogenic species which mature in fish and allogenic species which mature in vertebrates other than fish and have a greater colonization potential and ability. Three groups of fish are distinguished: salmonids, in which helminth communities are generally dominated by autogenic species which are also responsible for most of the similarity within and between localities; cyprinids, in which they are dominated by allogenic species which are also responsible for most of the similarity within and between localities; and anguillids, whose helminth communities exhibit intermediate features with neither category consistently dominating nor providing a clear pattern of similarity. Recognition and appreciation of the different colonization strategies of autogenic and allogenic helminths in respect of host vagility and ability to cross land or sea barriers and break down habitat isolation, and their period of residence in a locality, whether transient or permanent, provides an understanding of, and explanation for, the observed patchy spatial distribution of many helminths. Comparison with other parts of the world indicates that colonization is a major determinant of helminth community structure.
An investigation of hookworm infection and reinfection following mass anthelmintic treatment in the South Indian fishing community of Vairavankuppam
Authors: Haswell-Elkins Melissa R. , Elkins D. B. , Manjula K. , Michael E. , Anderson R. M. 
Published: June 2009

SUMMARYHookworm infections, as assessed by counting worms expelled following anthelmintic treatment and by egg output, were found to be of low prevalence and intensity in a South Indian fishing community. The initial overall prevalence of infection in the community was 43%, and the average burden was estimated at 2·2 hookworms per person. The age profiles of prevalence and intensity differed between males and females, with the latter harbouring significantly higher levels of infection. Children of both sexes under 10 years of age rarely harboured hookworms. Treatment with pyrantel pamoate was estimated to be 91% effective in clearing hookworm infections. Egg counts made on stools collected during an 11-month period of reinfection indicated that female patients became reinfected soon after treatment, while little hookworm egg excretion was observed in males during the observation period following treatment. Females acquired a significantly higher number of worms during the reinfection period compared with males, although the average burden in females reached only 28% of the initial, pre-treatment level. The hookworm population consisted of predominantly Necator americanus, and less than 10% of Ancylostoma duodenale. The parasites were highly aggregated within the host population with 10% of the community harbouring over 65% of the total hookworms. Low values of the negative binomial aggregation parameter, k, (indicating extreme over-dispersion) were recorded in groups stratified by age and sex. Highly significant positive correlations were observed between the initial (pre-treatment) and reinfection worm burdens of female (but not of male) patients. It is suggested that occupational practices related to walking through areas contaminated with hookworm larvae play an important role in generating the observed patterns of infection within this community.
The ultrastructure of the scolex–neck syncytium, neck cells and frontal gland cells of Caryophyllaeus laticeps (Caryophyllidea: Cestoda)
Authors: Sylvia Richards K. , Arme C. 
Published: June 2009

SUMMARYThe syncytium of the scolex and neck regions of Caryophyllaeus laticeps differs from that of the remainder of the body in a number of ways. The microtriches have short shafts and lamellated spines and the surface cytoplasm is characterized by numerous elongated granules, occasional lipid-like bodies and, in the scolex region, is penetrated by ducts from the frontal glands. The elongated granules arise from the tegumentary neck cells and pass into the syncytium via narrow cell processes possessing extensions of the neck cell microtubule system. The granules have a peripheral sub-structure of regularly spaced electron-lucent areas. Evidence suggests that the granular material becomes more diffuse before extrusion. The spherical, lipid-like bodies also arise from the neck cells, but extrusion from the syncytium was not observed. Homology of the neck cells with the tegumentary cells of the rest of the body is discussed. The frontal glands are restricted to the scolex apex and secrete spherical or sub-spherical, homogeneous granules. The cells, with microtubule-lined ducts, open to the surface via pores which possess an electron-dense ring at which point the microtubule system terminates. Sensory bulbs are also present and will be described in a subsequent communication. The inter-relationships of the gland distribution, scolex morphology and host pathology are discussed.
Nutritional aspects of Ascaris infection in young protein-deficient pigs
Authors: Forsum E. , Nesheim M. C. , Crompton D. W. T. 
Published: June 2009

SUMMARYExperiments were carried out to investigate the effects of Ascaris suum infection on the growth, food intake, nitrogen and fat utilization and intestinal function of young pigs receiving diets low in protein. An infection procedure was developed which provided relatively uniform and heavy infections in pigs under study. Ascaris-infected pigs showed statistically significant reduction in growth rate and food intake compared to uninfected controls. The reduction in growth rate was observed after the A. suum were mature and eggs were observed in the faeces of pigs. The degree of growth retardation was significantly correlated with worm burden. Infected pigs showed no consistent reduction in nitrogen and total solids digestibility compared to controls but fat digestion was reduced. The infected pigs showed reduced nitrogen retention compared to uninfected controls. Ascaris-infected pigs had heavier intestinal tracts with increased size of the tunica muscularis. Lactase activity in mucosa from infected pigs was significantly lower than in controls, whereas no consistent effect was observed in mucosal sucrase and maltase activity. When Ascaris-infected pigs were given an oral lactose load, blood glucose levels rose less than in control pigs, suggesting that the infection resulted in impaired lactose tolerance.
Schistosoma mansonihost–parasite relationship: interaction of contrapsin with adult worms
Authors: Modha J. , Doenhoff M. J. 
Published: June 2009

SUMMARYContrapsin, a serine protease inhibitor (serpin) present in mouse serum, was compared with that found in adultSchistosoma mansoniworm homogenates, which although immunologically identical to contrapsin in mouse serum, had a higher molecular weight in Western blotting. Immunolocalization studies demonstrated parasite-associated contrapsin on the surface and interstitial cells of adult male worms. After extraction of these parasites with Triton X-114, contrapsin was found in the aqueous phase of the detergent, suggesting it is unlikely to be an integral membrane protein. Treatment of adult worms with deoxycholate resulted in a change in the electrophoretic behaviour of worm-derived contrapsin. Parallel studies with trypsin suggested this was due to interaction of the serpin with a protease. Using porcine pancreatic trypsin as a model for a putative schistosome protease reacting with contrapsin, we have shown that trypsin, following complex formation with contrapsin, loses immunogenicity. Thus, when contrapsin–trypsin complexes were used as immunogen, the resulting antisera contained antibodies to contrapsin and contrapsin–trypsin complexes only, and none to native trypsin. Thus, epitopes characterizing native trypsin were presumably either masked following complex formation with contrapsin, or their processing and presentation to antigen presenting cells was suppressed, so that an antibody response was not mounted against them. These observations encourage speculation thatS. mansonimay be elaborating an immune evasion strategy whereby immunologically sensitive proteases are first complexed with host serpins, which would render them immunogenically inert, and then cleared from the circulation by the host's reticulo-endothelial system. In this way the immune system would be unable to ‘see’ sensitive parasite proteases sufficiently to mount a response against the parasite.
Localization of parasite antigens inCryptosporidium parvum-infected epithelial cells using monoclonal antibodies
Authors: McDonald V. , McCrossan M. V. , Petry F. 
Published: June 2009

SUMMARYAn immunogold ultrastructural study was made ofCryptosporidium parvum-infected intestinal cells from SCID mice to locate parasite antigens recognized by monoclonal antibodies raised against sporozoite or oocyst wall antigens. The results suggested that these antigens were present in more than one life-cycle stage and demonstrated that the intracellular parasite modified the parasitophorous vacuole membrane and villous membrane surrounding the parasite. In an immuno-fluorescence antibody test monoclonal antibody (MAb) IB5 reacted with the oocyst wall, MAb 2C3 with the whole sporozoite and MAb 2B2 with the sporozoite surface. Western and dot-blot studies demonstrated that different carbohydrate epitopes were recognized by the respective sporozoite-reactive antibodies. In the ultrastructural examination MAb 1B5 reacted with macro- and microgametocytes as well as the oocyst wall. In the macrogametocyte MAb 1B5 recognized the large electron-dense bodies characteristic of this stage and, in some parasites, the parasitophorous vacuole and the parasite pellicle. The sporozoite-reactive MAbs were able to bind to all developmental stages. These antibodies recognized the parasite cytoplasm and, additionally, MAb 2B2 produced substantial labelling of the parasite membrane. Significantly, both these antibodies also detected antigen in the parasitophorous vacuole membrane and, to a lesser extent, the villous membrane surrounding the parasite.