bluuebunny/crossref_metadata_2025_split huggingface dataset:
Host specificity in Schistocephalus solidus
Authors: Bråten Trond 
Published: June 2009

Investigations on the host specificity of plerocercoids of Schistocephalus solidus were carried out using the technique of surgically transferring plerocercoids from the body cavity of Gasterosteus aculeatus to various other fish. Plerocercoids survived in all cases when transferred from G. aculeatus to other G. aculeatus; when tranferred to Pungitius pungitius the worms survived for long periods but failed to grow. Plerocercoids transferred to Coitus gobio, Nemacheilus barbatula, Phoxinus phoxinus, Salmo trutta, Coregonus clupeoides, Perca fluviatilis, Rutilus rutilus and Esox lucius always died within 2–10 days after being transferred. Electron-microscopic examinations of the tegument of plerocercoids transferred to new hosts showed: in G. aculeatus normal appearance throughout the experiment; in P. pungitius degeneration of the microtrichs after 6 days; and in S. trutta complete destruction of the tegument in 7 days.Plerocercoids of the genus Diphyllobothrium survived the transfer from Gasterosteus aculeatus to Salmo trutta and continued to grow in their new host.Infection of fish with S. solidus by feeding infected copepods and by aspetic injection of procercoids into the body cavity of the fish were also tried. Gasterosteus aculeatus became infected using both these methods but it was not possible to infect Pungitius pungitius.
The dynamics of the host–parasite relationship
Authors: Wagland B. M. , Dineen J. K. 
Published: June 2009

A group of thirty-nine Merino-Border Leicester cross-bred lambs were given six sensitizing doses each of 3000 infective Haemonchus contortus larvae. Previous studies showed that this treatment produced a state of immunological exhaustion (Dineen & Wagland, 1966a). In the present study the regeneration of the immunological response was followed by challenging the sensitized animals and previously uninfected control animals with 3000 infective larvae at 2, 4, 8 and 16 weeks after termination of the sensitizing infections with an anthelmintic. Faecal egg counts were carried out on infected animals twice weekly throughout the course of the experiment, and differential worm counts were performed on groups of animals slaughtered 48 days after challenge.The results show that maximum regeneration of the immune response occurred when periods of 4 and 8 weeks were permitted to elapse between removal of the sensitizing infections and challenge. At 16 weeks the response of the sensitized animals to challenge infection was not significantly different from that of the control animals.In contrast to results recorded in the previous communication, a high mortality (49%) occurred among the sheep during sensitization. In the earlier experiment the sensitizing infections were given at fortnightly intervals whereas they were given at weekly intervals in the present experiment.Interpretation of the study is based upon the threshold behaviour of immunological responsiveness in parasite immunity, the occurrence of an immunological latent period and the relationship of this period to the developmental rate of the parasite, the susceptibility of the 4th larval stage to immunological attack, and the immunological privilege of the adult worm. These phenomena have been described in previous communications in the present series.We are greatly indebted to Mr Emil Teleki and Misses Helen Giller and Lindy Stothart for their excellent technical assistance.
Eimeria phasiani Tyzzer, 1929—a coccidium from the pheasant (Phasianus colchicus). II. Pathogenicity and drug action
Authors: Trigg P. I. 
Published: June 2009

Eimeria phasiani was shown to be pathogenic to young pheasant poults. Doses of 100000 or more oocysts proved fatal to birds up to 3 weeks old. Lesser doses produced losses in the live-weight gain of the host.Two separate strains of E. phasiani were completely susceptible to 0·006% (w/w) Sulphaquinoxaline, but less so to 0·006% (w/w) Amprolium and 0·0125% (w/w) Zoalene.I should like to express my sincere gratitude to Dr E. U. Canning for her supervision and helpful advice, and to Professor O. W. Richards, F.R.S., for permission to work at the Imperial College Field Station. I am also grateful to Mr T. H. Blank, of the Eley Game Advisory Service, Fordingbridge, Hants, who gave day-old pheasant chicks for this study.The work was financed by a scholarship from the Agricultural Research Council.
The function and ecological significance of the pharyngeal ridges occurring in the larvae of some cyclorrhaphous Diptera
Authors: Dowding Valerie M. 
Published: June 2009

The anatomy and function of the pharyngeal ridges, which occur in the larvae of saprophagous Cyclorrhapha but are generally absent in biontophagous forms, were investigated.The ridges extend throughout the length of the ventral aspect of the pharynx and lie in an evagination of its floor. They enclose channels which narrow and disappear posteriorly but are open anteriorly. Each ridge consists of a longitudinal plate projecting dorsally from the floor of the pharynx, the bifurcated upper edge of the plate bears, one on each side, a row of lateral lamellae, each about 0·3 μm thick. They are set vertically at regular intervals of just less than 1 μm. The lateral lamellae of adjacent ridges are closely apposed and completely roof over the channels between the ridges. Anteriorly the upper arms of the ridges are fused together.The lamellae form a sieve which retains particles of 0·6 μm and above in size as the relaxation of the pharyngeal dilator muscles allows the roof to descend so forcing liquid downward between the lamellae. InCalliphora vicina(Syn.C. erythrocephala) the sieve concentrates a suspension of 2700 particles of 4–7 μm per mm3between five and six times. The natural food consists largely of bacteria.Fungus spores and pollen grains of selected sizes were used to demonstrate the movements of particulate material in the pharynx and to define the upper size limit of the particles ingested.Swallowing is effected by simultaneous relaxation of the anterior dilator and transverse muscles of the pharynx, with contraction of the posterior dilator muscles; the transverse muscles are otherwise maintained in a state of contraction closing the posterior exit from the pharynx.Starved third-instar larvae ofC. vicinacan ingest 50% of their body weight in 6 min.The larvae of the Cyclorrhapha which possess pharyngeal ridges are essentially particle feeders. The ridges form a sieve by means of which food is concentrated and the amount of non-nutritious liquid ingested is reduced. The lack of pharyngeal ridges in larvae feeding on living material is correlated with the constant and high nutritive value of both the solid and the liquid fractions of the food.I should like to thank Dr P. Tate for his help and encouragement during the course of this work which was carried out during the tenure of a Postgraduate Studentship awarded by the Agricultural Research Council. Thanks are also due to the staff of the Plant Pathology subdepartment of the Botany School, Cambridge, for their help in obtaining fungus spores of suitable sizes.
Basic concepts and new aspects of vaccine development
Authors: Roitt I. M. 
Published: June 2009

AbstractI wish to thank the Society for inviting me to give the Introductory Talk in this Symposium. It is going to centre around what might be called ‘epitope specific’ immunization and I want to draw your attention to a number of factors which will be bound to affect any new approach to the development of vaccines. To begin with, it is now clear that complex antigens, such as those associated with parasites, present many different epitopes to the immune system. These epitopes are ‘seen’ by different cell types using different receptors and epitope recognition can activate a number of different effector systems.
An update on candidate malaria vaccines
Authors: Mitchell G. H. 
Published: June 2009

AbstractThe purpose of this work is to review the progress towards malaria vaccination that has been made over the last four or so years, and the prospects and difficulties as they now appear. Although some of the older literature will be referred to as necessary background, it is not treated here in any detail. The reader who wishes for a fuller historical perspective should see, for instance, Brown (1969), Cohen & Mitchell (1978), Desowitz & Miller (1980), Mitchell (1984), Miller, David & Hadley (1984), Heidrich (1986) and, specifically for a consideration of sporozoite vaccination, Nussenzweig & Nussenzweig (1984, 1986). Naturally, any summary of vaccination will lean on the immunology of the disease, but malaria immunology is not reviewed here in its own right. The reader requiring the most recent attempt to cover this field should see the work edited by Perlmann & Wigzell (1988); some individual chapters of that volume will be referred to below.
Sterile immunity, coinfectious immunity and strain differences in Babesia bigemina infections
Authors: Callow L. L. 
Published: June 2009

The acquired immunity of twenty-eight splenectomized and twenty-three intact cattle following primary inoculation with either of two strains (the Y and the R strain) of Babesia bigemina was investigated. Some of these animals were carriers, while others had ceased to be infected. Observations were made on the response of splenectomized animals challenged up to four times with the original infecting (homologous) strain and finally with the heterologous strain.In the splenectomized animals, a total of sixty-three homologous challenges produced parasitaemias in only twenty-seven instances, and these were generally delayed and of lower intensity than in control animals. Fifteen negative transmission tests performed shortly after thirty-two challenges showed that it was difficult to re-establish the homologous strain in some animals that had achieved self-cure. Substantial homologous immunity had developed within 16 weeks of the primary infection in animals which were no longer carrying B. bigemina.All twenty-one splenectomized animals subjected to heterologous challenge developed well-marked parasitaemias. Nine of these had been highly immune to homologous challenge 2 weeks earlier. Eight of the twenty-one were carriers at the time of challenge and these showed much lower parasitaemias than the self-cured animals which almost invariably were acutely affected.Challenges of twenty-three intact steers confirmed that the two strains differed immunologically. Six of twelve challenged homologously failed to show detectable parasitaemia, whereas all eleven challenged heterologously developed parasitaemias.
Studies onSchistocephalus solidus
Authors: Sinha D. P. , Hopkins C. A. 
Published: June 2009

The growth rate ofSchistocephalus soliduswas measured in culture at 4°, 7°, 12°, 17°, 23°, 27°, 30°, 33°, 35° and 40 °C. Between 7° and 23 °C the rate of growth increased nearly exponentially, with aQ10of 3·6. Between 23° and 27 °C growth rate was maximal; above 27 °C, after 8 days in culture, weight increase was shown only by worms which were too small to mature. Even in these worms the weight increase was very small and was probably due to partial maturation which occurs from 30 °C upwards. The larger the plerocercoid and the higher the temperature up to 40 °C the bigger the percentage weight loss, due to earlier maturation.Incubation of plerocercoids for 4 days at 35 °C, although inducing maturation and suppressing somatic growth, did not destroy the ability of the worm to grow when returned to 23 °C.Two hypotheses to explain the pattern of morphogenesis inSchistocephalusplerocercoids and adults are propounded; the evidence favours the existence of two enzyme systems, one controlling somatic growth with peak efficiency near 23 °C and the other controlling maturation with peak efficiency near 40 °C.The authors gratefully acknowledge financial support for this work from Shell International Petroleum Company Limited. It is also a pleasure to thank Miss Patricia Grant for technical help.
A morphological and biometrical study of the blood forms ofTrypanosoma suisOchmann, 1905
Authors: Stephen L. E. 
Published: June 2009

The status ofTrypanosoma suiswas held in doubt from the time it was first seen in 1905 until it was re-discovered and carefully studied in the Belgian Congo in 1954.A description is given of the morphology of single and dividing forms ofT. suisas seen in stained thin films made from the blood of infected pigs, and a selection of these is illustrated by line drawings. Briefly this trypanosome is short and stumpy with a free flagellum.A biometrical study was made on 200 organisms, showing a normal length distribution with a range from 8·5 to 18·5μ, and mean = 14·43μ.The monomorphism of the trypanosome is verified, and—because of its development in the salivary glands ofGlossina—its systematic position as a monomorphic subgroup of theBruceigroup is confirmed.I am much indebted to Dr C. A. Hoare, F.R.S., for the loan of the blood films used in this study and for his interest in the work. I am also grateful to Professor P. C. C. Garnham for providing me with accommodation and equipment at the London School of Hygiene and Tropical Medicine.
The life cycle of the monogeneanEntobdella soleae, a skin parasite of the common sole
Authors: Kearn G. C. 
Published: June 2009

The life cycle ofEntobdella soleae, a monogenean skin-parasite of a marine bottom-living flatfish (Solea solea) has been described and related to the habits of the host, which buries itself in the sediment for some time each day and when not buried rarely moves more than a few centimetres from the sea bottom.The eggs of the parasite are laid by specimens attached to the lower surface of the host and are anchored to sand grains on the sea bottom by an egg stalk bearing sticky droplets. The anchoring device may prevent the eggs from being carried by water currents vertically or laterally out of the region inhabited by soles.The free-swimming oncomiracidium which hatches from the egg invades the anterior part of the upper surface of the fish, which is the only part exposed when the fish is buried in the sand. After a short period of development on the upper surface the parasite emigrates to the lower surface where sexual maturity is reached.Adult parasites, which are distributed randomly on the lower surface, are orientated with the adhesive organ upstream with respect to water currents produced by the forward locomotion of the host, but the parasites are capable of moving from place to place on the lower surface of the fish. This movement of the parasite may be connected with the nature of the food.I wish to thank the Director and Staff of the Plymouth Laboratory and in particular Mr J. E. Green, for invaluable assistance. I am also very grateful to Dr J. Llewellyn for advice and criticism. The work was conducted during the tenure of a Fishery Research Training Grant from the Development Commission.
Reproduction in the daughter sporocyst of Cercaria bucephalopsis haimeana (Lacaze-Duthiers, 1854) (Bucephalidae) and Cercaria dichotoma Lebour, 1911 (non Müller) (Gymnophallidae)
Authors: James B. L. , Bowers E. A. 
Published: June 2009

The germ-cell cycle and method of reproduction in the daughter sporocysts of the bucephalid Cercaria bucephalopsis haimeana (Lacaze-Duthiers, 1854) and the gymnophallid Cercaria dichotoma Lebour, 1911 (non Müller) from the edible cockle, Cardium edule L., have been investigated by the examination of stained sections. A review is given of the principal interpretative theories which attempt to explain the nature of the reproduction and the homology of the germinal sacs of the Digenea. It is suggested that the life-cycle includes a cyclic alternation of homologous generations. Of these, the miracidium/mother-sporocyst and the daughter germinal-sac generations usually reproduce by apomictic parthenogenesis but polyembryony may also occur secondarily in some species.We are very grateful to Dr Gwendolen Rees and Professor E. W. Knight-Jones for considerable help with the manuscript.
Electron-microscope studies of Fasciola hepatica II. The interrelationship of the parenchyma with other organ systems
Authors: Gallagher S. S. E. , Threadgold L. T. 
Published: June 2009

The structural relationship between cells of the parenchyma and those of the alimentary and excretory systems, and tegument are described.Junctional complexes are formed in areas of close cell apposition. They occur laterally on invaginations of parenchymal processes which are embedded in the epithelial cells of the alimentary and excretory systems, and on flat plaques between parenchymal cells and the tegument.The ultrastructure of the complexes has been resolved and a three-dimensional interpretation is put forward. It is suggested that the complex is a type of desmosome.The findings reported here add support to the suggestion made in a previous paper that the parenchyma may function as a transport system in this fluke.We wish to acknowledge grants from the Wellcome Trust and the S.R.C. for the purchase of an Akashi TRS 50 and an A.E.I. EM 6B electron-microscope respectively. This research and that reported in a previous paper were carried out while one of us (S.S.E.G.) was in receipt of a Training Studentship Grant from the Wellcome Trust.We also wish to thank Mr W. Ferguson and Mr A. Lyness for photographic and technical assistance.
The in vitro effect of hexachlorophene on some enzymes in the liver fluke, Fasciola hepatica L.
Authors: Thorsell Walborg 
Published: June 2009

The effect of hexachlorophene, a fasciolicide, on some enzyme systems in the liver fluke was studied. The enzymes were adenosine triphosphatase, succinate oxidase and cholinesterase. Adenosine triphosphatase was activated, whereas succinate oxidase and cholinesterase were inhibited when homogenized flukes were incubated in some concentrations of hexachlorophene. Of the three enzyme systems studied in flukes killed by hexachlorophene, only the succinate system showed reduced activity, whereas the other two showed almost normal activities. The study indicates that biochemical changes are associated with the effect of hexachlorophene on the liver fluke.Thanks are due to Dr C. Grant for critical examination of the language, to Miss Maarja Kippar for valuable help with the experiments and to Mrs Astrid Holmström for the typing of the manuscript.This work was supported by grants A 1108/B 904 and A 1635/B 1299 from Jordbrukets Forskningsråd.
The course of infection and egg production ofPolymorphus minutus(Acanthocephala) in domestic ducks
Authors: Crompton D. W. T. , Whitfield P. J. 
Published: June 2009

Laboratory infections ofPolymorphus minutusin domestic ducks have been studied, and the parasites have been found to move posteriorly for a distance of about 4% of the host's intestinal length during the course of the infection.No evidence has been found for male and female worms having different attachment zones.Worms which had become attached anterior to a position 60% along the intestinal length were considered to be more likely to move or be expelled from the host before other worms in the population.Growth of male and female worms was studied by weight measurements. The growth rates of worms of both sexes are similar during the first week of the infection, but by the third week the weight of female worms is more than twice that of male worms.Mature eggs were first found in the host's faeces from 22 to 25 days after the beginning of the infection. Egg release continued for a variable period depending on the number of female worms present in the host.The average peak rates of egg production were 1700, 2000 and 700 eggs/day/ worm for the three cases studied.Eggs were estimated to remain for 50–100 min in the duck's intestine after being released by the worms but before being passed out of the host.The introduction of a Perspex cannula into the small intestine of a domestic duck does not disturb the environment ofP. minutus.We are most grateful to Dr R. C. Campbell, School of Agriculture, University of Cambridge, for all his help and advice about the statistical analysis employed in this work, to Mr J. A. F. Fozzard, Department of Anatomy, for taking the radiograph, to Dr P. Tate for helpful discussions, and to the S.R.C. for a grant for P.J.W.
The egg, oncomiracidium and larval development ofEntobdella soleae, a monogenean skin parasite of the common sole
Authors: Kearn G. C. 
Published: June 2009

The form of the egg, the structure of the oncomiracidium and the subsequent development ofEntobdella soleae, a monogenean skin parasite of the common sole, are described. The reproductive organs develop in a constant sequence and the parasite is protandrous. Glands of Goto were observed in post-oncomiracidia of all ages.The early embryo ofE. soleaepossesses eight pairs of marginal hooklets and two pairs of hamuli. One pair of hooklets, centrally situated on the adhesive organ, undergoes metamorphosis and becomes the pair of accessory sclerites associated with the hamuli in the adult.My thanks are due to Dr J. Llewellyn for continued advice and criticism. The work was conducted during the tenure of a Fishery Research Training Grant from the Development Commission.
The attachment of the monogenean Diplozoon paradoxum to the gills of Rutilus rutilus L. II. Structure and mechanism of the adhesive apparatus.
Authors: Owen I. L. 
Published: June 2009

The adhesive apparatus of Diplozoon paradoxum consists of four pairs of clamps and a pair of small hooks which apparently persists from the larval stage. The sclerotized framework which supports each clamp bears great resemblance to that of a Discocotyle clamp but certain differences, particularly in the fair-lead region, may make it mechanically more efficient.A clamp of Diplozoon paradoxum operates on an extrinsic muscle-tendon-fair-lead-hinged-jaws principle as do the clamps of Discocotyle, Plectanocotyle and Kuhnia. It appears likely that other species of Diplozoon will be found to possess this clamping mechanism despite statements to the contrary.It is a pleasure to record my thanks to Dr F. G. Rees, University College of Wales, Aberystwyth, for her encouragement and guidance and to Dr J. Llewellyn, University of Birmingham, for his valuable help and critical reading of the manuscript. This work was done while receiving a grant from the Department of Scientific and Industrial Research.
A new species of Lobochona, L. insularum sp.nov. (Ciliata: Chonotrichida) on a gribble from Hawaii
Authors: Matsudo Hitoshi , Mohr John Luther 
Published: June 2009

Lobochona insularum sp.nov., a collar ciliate (Chonotrichida), an ectocommensal on the pleopodal bristles of a gribble from Hawaii, is described. L. insularum differs from the previously described chonotrichidan ectocommensals of the gribbles, L. limnoriae on Limnoria lignorum and Lobochona prorates on Limnoria tripunctata, in the outlines of the body and of the marginal lappets of the collar.This work was supported by a grant from the National Science Foundation. Various facilities were made available by the Allan Hancock Foundation of the University of Southern California.Acknowledgement is given to Dr Bayard H. McConnaughey, who discovered the organism and prepared the slides.