bluuebunny/crossref_metadata_2025 huggingface dataset:
The morphology, formation and development of cysts ofEntamoeba
Authors: McConnachie Elspeth W.
Published: June 2009

Parasitic amoebae of the genusEntamoebaare transmitted from one host to another as cysts. The active amoeboid forms are so adapted to life within their particular hosts that, outside the host, they soon die, but encysted stages survive conditions fatal to the unprotected amoebae. The cyst is an integral and critical phase in the life-cycle ofEntamoeba;its attributes directly influence the dissemination of the organism, and are an important aspect in the epidemiology of amoebiasis. The following account of the morphology, formation and development of the cysts ofEntamoebais an assessment of present knowledge, and is not a comprehensive review of all available observations.
Parasites as biological models
Authors: Smyth J. D.
Published: June 2009

The value of metazoan parasites as models for the investigation of fundamental biological phenomena is discussed. The fields in which they are of particular value include: immunology, neuromuscular physiology, nucleo-cytoplasmic relationships, genetics, cyto-differentiation, comparative biochemistry.

After reviewing some examples of experimental organisms in trematodes and nematodes, the cestode,Echinococcus granulosus, in particular, is examined as a model.

Problems of particular interest in this organism are: the function of the rostellar gland, whose cells release a secretion which has its origin in the nuclei of these cells; the mode of action of the suckers, whichin vivoare thought to remain in a state of sustained contraction; the mode of digestion at the host–parasite interface—membrane digestion appears to be involved; the various modes of membrane transport through the tegument; factors controlling cystic or strobilar differentiation, a problem viewed in the light of the Jacob–Monad model of gene action.

A hypothetical control circuit for differentiation of the stages in parasite life-cycles in general is also put forward.

Some preliminary experiments on thein vitroculture ofTaenia serialis, are described. The factors controlling differentiation into cystic or strobilar directions appear to be generally similar to those which operate forEchinococcus granulosus.

It was stressed that many other species of parasites could also serve as models for investigating similar or related problems.

Some of the studies described here were supported by grants from the Australian Wool Board, the U.S. Public Health Service (Grant no. A 107452–02) and the Rural Credits Development Fund.

I am grateful to Mr D. Heath for the provision of the micrographs ofTaenia pisiformisandT. serialisin P1. 2, figs. 2, 3.
Population studies on the infective stage of some nematode parasites of sheep
Authors: Donald A. D. , Leslie R. T.
Published: June 2009

Observations have been made on the distribution of faecal deposits on a number of small fields of varying size stocked with varying numbers of sheep. These studies were undertaken to examine certain hypotheses proposed in the construction of mathematical models for the distribution of strongyloid nematode infective larvae in pastures grazed by sheep.

The negative binomial distribution was found to provide a reasonable empirical description of the distribution of faeces, although there was evidence of departure from the negative binomial on the largest field.

Although, tentatively, the distributions were additive with respect to the number of sheep, there was evidence of departure from additivity in respect of field area and time. The implications of these findings for the model are discussed.

Significant positive correlations were found between successive time intervals in the number of faecal deposits present in individual subplots of the majority of fields. It is suggested that these arise from the tendency of sheep to use the same portion of a field for resting and rumination when heavy concentrations of faeces are deposited. The effects of this and other possible patterns of grazing and faecal deposition are discussed in relation to the intake of strongyloid infective larvae.

The average number of discrete deposits of faeces on pasture produced per sheep per day was greater in flocks producing faeces in pellet form than in flocks producing soft faecal masses. However, within faeces types, there was evidence that the expected number of deposits produced per sheep per day could reasonably be assumed constant.

The greater part of this work was carried out while one of us (A.D.D.) was the holder of a C.S.I.R.O. Overseas Research Studentship. For his advice and constructive criticism I am much indebted to Dr H. D. Crofton, under whose supervision this study was undertaken. My thanks go also to Professor J. E. Harris, C.B.E., F.R.S., for the provision of facilities in the Department of Zoology, and to Professor T. K. Ewer and Mr M. R. McCrea for their willing co-operation in the provision and handling of pastures and sheep at the School of Veterinary Science, Langford.

Mr David Culpin and Mrs Jean Williams, of the Division of Mathematical Statistics, were responsible for programming and organizing the calculations on the CDC 3200 Computer, and were consistently helpful in proposing and criticizing tests and procedures.
Some observations on the free-living stages of Ostertagia ostertagi, a stomach worm of cattle
Authors: Rose J. H.
Published: June 2009

Outdoor observations were made on the rate of development of the free-living stages of O. ostertagi at different times of the year, and on the migratory activities and longevity of the larvae in faeces, on herbage and in soil.

The effect of temperature on the rate of development of eggs and larvae in faeces, and the effect of temperature and humidity on the longevity of eggs and larvae when separated from faeces, were studied in the laboratory.

The results of these observations are discussed in relation to translation (that is, the process whereby eggs in faeces become infective larvae on herbage available to the grazing animal) and to the transmission of infection in the field.

I wish to thank Mr J. F. Michel for providing the infected faeces, and Mr D. A. Griffiths for technical assistance.
Studies on the resistance of rats to the nematode Nippostrongylus muris (Yokogawa, 1920). I. Dosage-mortality relationship
Authors: Hunter G. C. , Leigh L. C.
Published: June 2009

The LD50 of Nippostrongylus muris for outbred hooded rats has been estimated. It was higher for males than for females and this does not appear to be due to weight differences. The distribution of times of death was bimodal; the peaks corresponding to different stages in the life cycle of the worm.

We wish to thank Mrs M. Whitehead for technical assistance and Mr I. McDonald for statistical analysis.
Electron microscope studies of Fasciola hepatica
Authors: Threadgold L. T. , Gallagher S. S. E.
Published: June 2009

The ultrastructure of the parenchyma and interstitial material and the interrelations between them are described.

The interstitial material, composed of a granular matrix containing fibres, is shown to ramify as a network between parenchymal cells and around organ systems. It is postulated that this structure is a ‘skeleton’.

In certain localized areas the interstitial material between parenchymal cells is absent and at these points adjacent cells are united by attachment plaques (desmosomes) without tonofibrils.

The possible functions of the parenchyma are considered and it is suggested that these cells are responsible not only for secreting the interstitial material, but also store glycogen and act, in the absence of a circulatory system, as a transport system for metabolites and excretory products.
A note on Polymastix Bütschli, 1884, from the colon of Periplaneta americana (Insecta: Dictyoptera)
Authors: Warhurst David C.
Published: June 2009

A flagellate morphologically similar to Polymastix melolonthae (Grassi, 1879) was found inhabiting the colons of three out of over 200 cockroaches (Periplaneta americana) examined. A morphological description of the flagellate is given.

I wish to express my thanks to Professor H. P. Moon, in whose department this work took place, for his help and advice; to my supervisor, Dr Marjorie G. Guthrie, for her advice, encouragement and constructive criticism, and also to Dr Ann Bishop, F.R.S., and Dr Elspeth W. McConnachie for their advice.
Distribution and pathogenicity of Tetrahymena limacis in the slug Deroceras reticulatum
Authors: Michelson E. H.
Published: June 2009

The distribution of Tetrahymena limacis in its natural host Deroceras reticulatum, and the tissue responses to infection are described. Contrary to previous observations, T. limacis occurred throughout the tissues and organs of its host; the organisms were especially numerous in the kidney, the mantle shield, and in grossly visible papules on the external epithelium. Aspirates from such papules yielded numerous ciliates.

T. limacis elicited a considerable pathologic response and appeared to contribute to an increase in morbidity and mortality among slugs. Tissue responses were focal (fibrotic encapsulation of isolated organisms) and diffuse (necrosis, mechanical tissue destruction, and metaplasia). Efforts to establish infection in seven species of molluscs other than D. reticulatum were unsuccessful.

An extramolluscan cyst stage of T. limacis is reported for the first time. Both resting and reproductive cysts were observed. Since free-swimming trophozoites of T. limacis are not long lived, the organism is more likely an obligate rather than a facultative parasite of molluscs. Observations also suggest that slugs are infected via the respiratory pore rather than orally.

It is a pleasure to acknowledge the aid and counsel given by Dr J. O. Corliss in identifying the ciliate and to Miss Lorin DuBois for technical assistance.
Helminth fauna of Nicaragua
Authors: Schmidt Gerald D. , Neiland Kenneth A.
Published: June 2009

Cestodes collected from birds of El Recreo, Zelaya, Nicaragua are reported. Sacciuterina mathevossiani sp.nov. from Rhamphocaenus rufiventris is the only species in the genus with 32 rostellar hooks, each 22–24 μm long, and with 5–9 testes. Angularella beema (Clerc, 1906) Strand, 1928, from Iridoprocne albilinea, is partially redescribed. Also reported are Dilepis undula (Schrank, 1788) Weinland, 1858, from Turdus grayi; Anomotaenia mutabilis (Rudolphi, 1819) Baer et Bona, 1960, from Florida caerulea; Ophiovalipora lintoni (Olsen, 1937) Coil, 1950, from Butorides viriscens; Hymenolepsis pellucida Fuhrmann, 1906, from Ramphocelus paserinii and Gymnostinops montezuma; and Raillietina (R). maplestonei Southwell, 1930, from Amazona autumnalis. All are new records for Nicaragua.

Thanks are expressed to Dr Thomas R. Howell, University of California who, assisted by Mr John Zeiger, collected and identified the hosts. The collecting of birds was supported in part by a grant to Dr Howell from the University of California Association in Tropical Biogeography. Gratitude is also expressed to Dr W. H. Coil, University of Kansas, who examined some of the specimens and offered helpful suggestions, and to Miss Dorothy B. Segal, Beltsville Parasitological Laboratory, for checking the records on Angularella.
Seasonal change in a balanced polymorphism in Haemonchus contortus populations
Authors: LeJambre Leo F. , Ractliffe L. H.
Published: June 2009

Twenty-one sheep were killed after having been kept for varying times on a pasture contaminated with Haemonchus contortus. The proportions of linguiform A to linguiform B phenotypes were estimated for the H. contortus populations of each sheep. They gave further evidence that the linguiform B phenotype gradually replaces the linguiform A phenotype during the summer. Given the genetic basis of the phenotype it is pointed out that this seasonal change would appear to be inconsistent with any theory stating that essentially only one generation of worms is involved in the yearly outbreaks of disease.
A quantitative approach to parasitism
Authors: Crofton H. D.
Published: June 2009

The frequency distribution of parasites among hosts is used as the basis of the quantitative assessment of the nature of parasitism. The host–parasite system is regarded as an ecological relationship between populations of two different species of organisms. From the overdispersed frequency distributions exemplified by the Negative Binomial distribution a specially truncated form is derived and shown to fit the data of Hynes & Nicholas (1963). The theoretical consequences are discussed and these form the basis of a definition of parasitism.

I am indebted to Professor H. B. N. Hynes who so readily understood my general aims and freely provided detailed information about his work. I also have great pleasure in thanking Professor John H. Whitlock, not only for the original computing facilities which he so generously provided, but also for his many other kindnesses. I am also very grateful to Dr Charles Henderson Jun. for his work on the original computer program and to Dr Mark Westwood for his ingenuity and labours in producing a new approach to the computations.
IsRhabdospora thelohani(Laguesse) a sporozoan parasite or a tissue cell of lower vertebrates?
Authors: Bannister L. H.
Published: June 2009

An examination with light and electron microscopes has been made of the cell type which is considered by some authors to be a sporozoan parasite,Rhabdospora thelohani, and by others to be a tissue cell of fishes and amphibians.

The cell type was found in the minnowPhoxinus phoxinusin many tissue sites, including olfactory and pharygneal epithelia, kidney, eyes and brain. In some specimens it could not be found in any tissue.

The cell has a thick fibrous wall, a basal nucleus, an apical mitochondrial zone, a Golgi body, and from 8 to 50 characteristic refractile rodlets.

The rodlets give a negative reaction to the Feulgen test for nuclear material, but are positive to the periodic acid–Schiff stain, a test for polysaccharide. Glycogen does not appear to be present in the rodlets.

Under certain circumstances the rods rupture the cell wall and may protrude in the apical region of the cell.

The structures described are discussed with the evidence for and against a parasitic interpretation of the cell. It is concluded thatRhabdosporais a protozoan parasite, whose exact functional and taxonomic status is as yet unknown.

I am grateful to Professor G. E. H. Foxon and to Professor P. C. C. Garnham for their encouragement, advice, and helpful criticism of the manuscript. I am further indebted to the National Spastics Society for the use of the electron microscope housed in Guy&s Hospital Medical School, and to Mr I. D. Bradbrook for his assistance with the histological techniques.
Eimeria phasiani Tyzzer, 1929—a coccidium from the pheasant (Phasianus colchicus) I. The life cycle
Authors: Trigg P. I.
Published: June 2009

The first full account of the life-cycle of an Eimeria sp. from the pheasant is given. The strain, isolated from pheasant chicks by single oocyst inoculation is identified as E. phasiani. It is shown that there are three distinct asexual stages prior to the onset of the sexual stage.

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 life-cycles and larval development of some acanthocotylids (Monogenea) from Plymouth rays
Authors: Kearn G. C.
Published: June 2009

Acanthocotylid (monogenean) parasites inhabit the skin of rays, and the lack of cilia on the infective larvae of these parasites may be an adaptation to the host's bottom-living habits.

Freshly hatched larvae must remain on the sea-bottom until a ray settles on top of them, when the larvae then have the opportunity to attach themselves to the host's ventral surface. Acanthocotyle lobianchi, which infects Raia montagui and R. clavata at Plymouth, becomes sexually mature on the host's ventral surface and rarely wanders from it, but A. elegans, which is found on R. clavata only, migrates to the dorsal surface of the host before reaching sexual maturity.

The larvae of acanthocotylids use their haptoral hooklets to attach themselves to the host's epidermis, but as the parasites increase in size the load on these hooks becomes acute. This load is relieved not as in other monogeneans by the development of hamuli but by the transformation of the posterior third of the larval body into an accessory ‘pseudohaptor’.

I am obliged to the Director and Staff of the Plymouth Laboratory for laboratory facilities and to Mr J. E. Green for his interest and help on many occasions.
Theilerial parasites isolated from carrier cattle afterimmunization withTheileria parvaby the infection and treatment method
Authors: Maritim A. C. , Young A. S. , Lesan A. C. , Ndungu S. G. , Mutugi J. J. , Stagg D. A.
Published: June 2009

Groups of cattle were immunized with 10−2dilutions of sporozoite stabilates ofTheileria parva lawrenceiderived from African buffaloes either alone or in combination withTheileria parva parvaderived from cattle and concomitant treatment with either long or short-acting formulations of oxytetracyline. At 90 or 120 days after infection, uninfectedRhipicephalus appendiculatusnymphal ticks were applied to individual immunized cattle and the resultant adults ticks were applied to individual susceptible cattle. Theilerial infection developed from ticks fed on 6 out of 11 animals investigated for evidence of a carrier state. Two additional animals were shown by cell-culture isolation to have persistent theilerial infections. Nine cattle infected with the parasites from carrier animals were treated with parvaquone and 7 recovered. These recovered cattle were then challenged with the original immunizing stabilates at 10° dilution together with the original immunized and carrier cattle. Six out of 7 cattle which had recovered from carrier-derived infection succumbed to this challenge and died but none of the original immunized cattle showed theilerial reactions. When a carrier-derived sporozoite stabilate was used to challenge cattle immune to the original immunizing parasite, they proved to be immune. Cattle immune to the carrier-derived parasites were all immune to challenge with the original parasite. A monoclonal antibody profile aginstT. parvaschizonts isolated by cell culture from samples of the experimental animals did not appear to be sensitive enough to determine the antigenic differences between the carrier-derived parasite and the original immunizing parasite. Indications are that the carrier state is not likely to produce new antigenic strains which would be dangerous to immunized cattle.
Adaptation of field strains ofRhipicephalus appendiculatusNeumann (Acarina: Ixodidae) to host resistance
Authors: Chiera J. W. , Newson R. M. , Karuhize G. R.
Published: June 2009

A comparison of feeding and breeding performance was made between a laboratory strain (LS) and two freshly collected field strains (FS1, FS2) ofRhipicephalus appendiculatus. The LS had been cultured for over 30 years on tick-susceptible rabbits. When fed on susceptible rabbits LS produced smaller eggs and unfed larvae, nymphs and adults than those of FS. Eggs and larvae from females engorged on cattle were larger than those from females engorged on rabbits. LS and FS females engorged on susceptible hosts were of similar weight, but the FS females were twice as heavy as LS females when tick-resistant hosts were used. A higher proportion of LS ticks than of FS ticks engorged on susceptible hosts, but a lower proportion on resistant hosts. Thus on susceptible hosts LS showed a higher reproduction efficiency than FS, but a lower one than FS on resistant hosts. The proportional reductions of engorged weights and numbers feeding successfully on resistant hosts were significantly lower for LS than FS ticks. Cross-resistance was low between LS and FS. Although all strains were affected by host resistance, it was concluded that the field strains were better adapted to withstand resistance than the laboratory strain.
The ecology of the free-living stages of Trichostrongylus colubriformis
Authors: Gibson T. E. , Everett G.
Published: June 2009

The development and survival of the eggs and larvae of T. colubriformis was studied by spreading the daily faecal output of an infected sheep for 1 or 2 weeks on grass plots 6 ft square. The observations were carried out for 3 years and broadly similar results were obtained in each year. Eggs placed on the ground from November to February failed to develop. A large proportion of the eggs placed on the ground in March disintegrate but those which develop do so slowly. Infective larvae are not produced for 8–12 weeks and they are relatively short lived. As conditions become more favourable development becomes more rapid, taking 8 weeks in April 6 weeks in May and only 1 week in June, July and August. A larger proportion of the eggs develop into infective larvae and their time of survival increases. On most plots larvae did not die out until the following April. The prolonged period of snow during the winter of 1962–63 tended to preserve larvae rather than kill them. The relevance of these results to the control of trichostrongylosis is discussed and it is concluded that it would be impossible under British conditions to devise a system of rotational grazing which would satisfactorily control trichostrongylosis and at the same time ensure economic utilization of the herbage.

We are grateful to Mr C. R. Phillips and Mr T. Doy for technical assistance during the course of this investigation.
Experiments on host-finding and host-specificity in the monogenean skin parasiteEntobdella soleae
Authors: Kearn G. C.
Published: June 2009

The oncomiracidium of the monogenean skin parasiteEntobdella soleaefinds its flatfish host,Solea solea, by chemoreception. The free-swimming larva responds to a specific substance secreted by the skin of the common sole, attaches itself to this skin and immediately sheds its ciliated epidermal cells. Larvae respond in the same way to agar jelly which has been in contact with the skin ofS. solea.

The oncomiracidia attach toS. soleaskin in preference to that of other soleid fishes (Buglossidium luteumandSolea variegata), pleuronectid fishes (Limanda limanda, Pleuronectes platessa) and elasmobranch flatfishes (Raiaspp.).

Larvae respond strongly to isolated epidermis fromSolea soleabut show no response to the fish's cornea, indicating that the attractive substance is produced by the mucus cells in the fish's epidermis.

The larvae attach with equal readiness to skin from the upper and lower surfaces ofS. solea.Thus the preponderance of young parasites on the upper surfaces of soles is due not to a preference for the upper skin but to the fact that the lower skin is in contact with the substratum and cannot be reached by the larvae.

These results led to speculations on the way in which host specificity evolved in the Monogenea.

I am indebted to Mr J. E. Green of the Plymouth Laboratory for setting up a tank containing infected soles and for maintaining the tank and feeding the fishes for many months.

I am also grateful to the Directors and Staff of the Plymouth Laboratory and the Fisheries Laboratory, Lowestoft, for hospitality and assistance. I am particularly grateful to Mr J. Riley of the Lowestoft Laboratory for providing various flatfishes.
Schistosomes fromHippopotamus amphibiusL.
Authors: Thurston June P.
Published: June 2009

The morphology of the adult blood flukeSchistosoma hippopotamisp.nov. fromHippopotamus amphibiusL. is described and compared with that of other species of the genusSchistosoma.
On a trematode of the genus Echinochasmus Dietz, 1909, with remarks on the species occurring in Indian carnivores
Authors: Gupta V. P. , Pande B. P.
Published: June 2009

In a survey on the worm parasites of cats in Calcutta, Chandler (1925) mentioned the common occurrence in dogs also of Echinochasmus perfoliatus (Ratz, 1908) which has also been listed by Bhalerao (1935) in cat, dog and man. According to Verma (1935), the dogs at Calcutta harboured three distinct flukes—a species of Echinochasmus, a heterophyid and a third species described by him under a new genus, Episthochasmus, as E. caninum. In a survey of the helminth parasites of pariah dogs examined at Calcutta, Mapleston & Bhaduri (1940) included Echinochasmus sp. amongst the six new records from India. Chatterji (1954) regarded Episthochasmus as a synonym of Episthmium Lühe, 1909 and Stephanoprora Odhner, 1911, Echinochasmus and Episthmium Lühe, 1909 as subgenera of Echinochasmus. A new species, based on two specimens collected from the intestine of pariah dog at Allahabad, was described as E. (Echinochasmus) canai. Relying on the character of the forward extension of vitelline follicles, Stephanoprora was to include forms with vitellaria extending to the posterior margins of anterior testis, Echinochasmus forms with vitelline follicles extending beyond the anterior testis but not anterior to the anterior margin of ventral sucker and Episthmium forms with follicles extending beyond the anterior margin of this sucker. Thus, Verma's species was named as E. (Episthmium) caninum.
Resistance to primaquine inPlasmodium gallinaceum, and the problem of resistance to quinoline compounds in malaria parasites
Authors: Bishop Ann
Published: June 2009

A tenfold enhancement of resistance to primaquine was obtained by maintaining a strain ofPlasmodium gallinaceumin a state of acute infection by serial passage of infected blood through young chicks treated with gradually increasing doses of the drug.

No loss in resistance to primaquine was observed when the resistant strain was transmitted through mosquitoes, though there was some loss in resistance to the maximum tolerated dose, but not to lower doses, when the strain was maintained in a state of acute infection through untreated chicks for 41 weeks.

The primaquine-resistant strain was cross-resistant to lower effective doses of pamaquin, and slightly less sensitive to quinine than the parent strain but the loss in sensitivity to chloroquine was only marginal. Sensitivity to proguanil, dihydrotriazine and pyrimethamine was normal.

Attempts were made to produce a chloroquine-resistant strain ofP. gallinaceumusing different doses of the drug but no change in sensitivity was observed though the experiments were continued for more than a year. An attempt to produce a chloroquine-resistant strain by treatment of a proguanil-resistant strain with chloroquine also failed.

The problem of resistance to quinoline compounds in different species ofPlasmodiumis discussed.
Neurobiology of parasitic platyhelminths: possible solutions to the problems of correlating structure with function
Authors: Pax R. A. , Bennett J. L.
Published: June 2009

This paper provides an overview of research on the nervous system of parasitic platyhelminths. We have emphasized studies concerned with the physiological, pharmacological and biochemical nature of the major small molecule neurotransmitters of these parasites. We have attempted to provide a critical review of the work by focusing on important unresolved issues. Finally, we have focused on some recent work in our laboratory, using patch-clamp recording techniques and quantitative fluorescence cytometry, as an example of newer methods that will hopefully resolve some of the unanswered questions concerning the nervous system of these parasites.
Observations on the life-cycle of Psilotrema oligoon (Linstow, 1887) Odhner, 1913, and on the larval stages of two other psilostome trematodes
Authors: Pike Alan W.
Published: June 2009

The species described in this paper were found in Bithynia tentaculata from the Wentloog level, near Cardiff, South Wales. The larval stages of Psilotrema oligoon are redescribed and the taxonomy of the adults discussed. C. frondicola sp.nov. is a psilostome cercaria which has the probable flame-cell formula 2 [4 + 4 + 4 + 4 + 3 + 3] = 44. It emerges at night or during early morning, is positively phototactic and will not normally encyst on anything but vegetation. C. granocutis sp.nov. is also a psilostome cercaria; it is very small and has the probable flame-cell formula 2 [3 + 3 + 3 + 3 + 3] = 30. It emerges during the afternoon and will encyst freely on a variety of substrata.

I thank Professor J. Brough of the Zoology Department, Cardiff, for the facilities provided, Dr D. A. Erasmus for supervising and encouraging this work and Dr S. M. Willmott, Director of the Commonwealth Bureau of Helminthology, for providing library facilities. This study was carried out during the tenure of a D.S.I.R. research studentship.
A hypothesis to account for the anterior migrations of adult Hymenolepis diminuta (Cestoda) and Moniliformis dubius (Acanthocephala) in the intestine of rats
Authors: Crompton D. W. T. , Whitfield P. J.
Published: June 2009

The cestode, Hymenolepis diminuta, and the acanthocephalan, Moniliformis dubius, were found, by Chandler (1939) and Burlingame & Chandler (1941) respectively, to undergo an anterior migration in the intestine of rats after the establishment of the infection. More recently, these results have been confirmed by Holmes (1961, 1962) who stated that it is not unlikely that the worms select optimum sites along one or more of the many gradients known or postulated to exist along the length of the small intestine.
Adhesion ofTrichomonas vaginalisto plastic surfaces: requirement for energy and serum constituents
Authors: Gold D. , Ofek I.
Published: June 2009

The ability ofTrichomonas vaginalisto adhere to plastic surfaces in the presence of various agents and under different growth conditions was examined in wells of microtitre plates containing unsupplemented TYI medium or the same, with various supplements. Following incubation, the wells were thoroughly washed and adhesion was determined by microscopic counting of the adherent organisms. There was no detectable adhesion in the absence of both serum and carbohydrate. Optimal adhesion (about 10–20% of the total number of parasites) was obtained throughout the growth curve in culture media supplemented with either serum or serum Cohn fractions IV–I (rich in α-globulin) or IV-4 (rich in α + β-globulin) and 25 mM glucose, maltose or fructose, but not in plates pre-coated with the Cohn fractions. Cohn fraction II + III (rich in β + γ-globulin) moderately enhanced adhesion while Cohn fractions II (rich in γ-globulin) or V (albumin), fibronectin, Tamm-Horsfall glycoproteins and polylysine were without effect. Non-metabolizable sugars (methyl derivatives of glucose, mannose or fucose) did not support growth, but, surprisingly, enhanced adhesion. At 4 °C, the trichomonads were not able to adhere and pre-adherent organisms detached from the plastic surface. Optimal adhesion was obtained at a pH range of 6·5–7·5 but was already detectable at pH 5·5. Cytochalasin E markedly suppressed adhesion. The data taken together suggest that the firm, serum-dependent adhesion ofT. vaginalisto plastic surfaces is apparently not influenced by the rate of multiplication, requires energy and the binding by the organisms of certain serum proteins, which possibly enhances their hydrophobic interaction with the plastic substratum.
Protein content of CBA/Ca mouse diet: relationship with host antibody responses and the population dynamics ofTrichuris muris(Nematoda) in repeated infection
Authors: Michael E. , Bundy D. A. P.
Published: June 2009

The influence of host dietary protein on acquired immunity and intestinal helminth population dynamics during repeated infection was studied using the mouse–Trichuris murisexperimental model. CBA/Ca mice fed a 2% (by mass) protein dietad libitummaintained body weight during the experiment, but when fed diets containing either 4% or 16% (by mass) protein gained weight steadily. Infection withT. murisdid not affect the growth of the latter mice but significantly reduced the growth of animals fed on the 2% protein diet. When repeatedly infected with either 5 or 50 eggs every 10 days, the mice fed the 2% or 4% protein diet accumulated adults in proportion to infection dose. The results show that this is due to both the establishment of larvae at each repeated infection and the survival of established adults. In contrast, very few worms were recovered from animals fed the 16% protein diet, principally as a result of the development of strong acquired immunity to reinfection.T. murisegg output/mouse increased with infection dose in animals fed the low protein diets, but no parasite eggs were detected in the faeces of hosts fed the 16% protein diet. Mouse antibody reponses to adult worm excretory/secretory antigen were time- and infection dose-dependent in all 3 dietary groups. The major finding was that the specific antibody response was more intense, both quantitatively (serum OD levels) and qualitatively (antigen recognition by IgG1), in mice fed the low protein diets, even though they remained susceptible to infection. This study shows that host dietary protein deficiency, even at levels irrelevant to normal growth, can markedly potentiate the transmission ofT. murisvia alterations in host resistance. The high levels of antibody in susceptible animals suggest that this defect in resistance is unlikely to be due to nutrient deficiency-associated defects in humoral immunity.
The fine structure of reproducing Toxoplasma gondii
Authors: Olisa Emeka G.
Published: June 2009

1. Different shapes and forms found in Toxoplasma gondii are associated with reproduction and growth. The functions of the toxoneme and the conoid are discussed.

2. A new structure, ‘lamella spiralis', is described in relation to the nucleus and the endoplasmic reticulum.

3. T. gondii reproduces either by dividing into two (binary fission) or by multiple division (schizogony), and by a type of endogenous budding. In the latter case small portions pinched off from the nucleus are rounded up to form several small organisms named ‘morulae'.

The author gratefully acknowledges the interest and valuable suggestions of Dr G. A. Gresham, M.D., who supervised this work; Dr J. M. Davis and Mr F. Allen, who were kind enough to read the manuscript critically, and Mr W. A. Mowlam for his technical help and advice on fixation techniques.

This work was carried out during the tenure of a research scholarship awarded by the United Kingdom Department of Technical Co-operation and the Eastern Nigerian Government.
On the use of age-intensity data to detect immunity to parasitic infections, with special reference to Schistosoma mansoni in Kenya
Authors: Fulford A. J. C. , Butterworth A. E. , Sturrock R. F. , Ouma J. H.
Published: June 2009

We consider two phenomena, related to the host age-intensity profiles of parasitic infections, which have been suggested to be indicative of acquired immunity: (i) a lower age of peak intensity among more intensely infected hosts; and (ii) a decline with age in the dispersion of the distribution of parasites between hosts. We demonstrate that these phenomena occur among Kenyan schoolchildren infected with Schistosoma mansoni, although the magnitude of both is small. We also examine the mathematical models underlying these predictions and conclude that both phenomena are possible in the absence of acquired immunity or, indeed, in the absence of any density-dependent effect. In our opinion, insufficient attention has been focused upon mathematical models, describing the null hypothesis, i.e. density-independent models. In particular, we regard the usual assumptions made for the two stochastic components of these models, describing the heterogeneity between hosts and the probabilistic nature of infection and death of parasites, as too rigid and unrealistic. We demonstrate that deviation from these assumptions undermines the qualitative distinctions between models which describe acquired immunity or density dependence and those which are density-independent.
Lectin binding to secretory structures, the cuticle and the surface coat ofToxocara canisinfective larvae
Authors: Page A. P. , Rudin W. , Maizels R. M.
Published: June 2009

Toxocara canisinfective larvae are known to produce abundant glycosylated molecules which may be found associated with the surface or secreted into their environment. Using a range of fluorescein-conjugated and gold-conjugated lectins, the localization of particular carbohydrates was defined on the surface of live parasites, and internally at the ultrastructural level. Surface exposure ofN-acetyl galactosamine andN-acetyl glucosamine was deduced by binding of FITC-conjugatedHelix pomatia(HPA) and wheat-germ agglutinins (WGA). These sugars appear to be associated with a densely staining surface coat as conventional immuno-electron microscopy procedures dissipate this coat and reveal no surface binding site for these lectins. However, by using cryo-immuno-electron microscopical (C-IEM) techniques, the surface coat is retained and can be shown to bind WGA. The fluorescent lectins also revealed strong WGA binding to the secretory and amphidial pores, while the buccal opening and the cuticular alae bound HPA. Corresponding results were obtained at the ultrastructural level. Thus, HPA bound to the electron-dense area of the cuticle, areas of local cuticular thickening such as the alae and buccal labia, as well as to the oesophageal lumen. WGA also bound to the thickened cuticle of the alae and the buccal opening, but showed no reaction to either the electron-dense layer of the cuticle or the oesophageal lumen. Unlike HPA, WGA did bind specifically to the secretory column contents and the electron-dense regions of the lips associated with the chemosensory amphids. The compartmentalization of the sugarsN-acetyl galactosamine andN-acetyl glucosamine, their sources and routes of surface expression and the possible association with the TES glycoprotein antigens are discussed.
Oxygen consumption in the presence of glucose and cytochemical localization of enzymes inHaemogregarina boyli
Authors: Lehmann D. L.
Published: June 2009

Uninfected erythrocytes ofRana boyli, in the presence of glucose, utilized 214μ1. O2/hr./108cells. Cells infected withHaemogregarina boyliincreased oxygen consumption approximately 12% for a 10% rate of infection. Alkaline phosphatase and zymohexase, but not acid phosphatase, urease, lipase or peroxidase, were demonstrated in the parasites by cytochemical means.
Observations on the taxonomy and biology of Tylenchorhynchus macrurus (Goodey, 1932) Filipjev, 1936 and Tylenchorhynchus icarus sp.nov.
Authors: Wallace H. R. , Greet D. N.
Published: June 2009

The large and small forms of Tylenchorhynchus macrurus are distinguished as separate species. The large form becomes T. icarus and differs from the small form, T. macrurus in the greater number of annules on the female tail, longer stylet and slimmer body. The oxygen consumption of both species is similar when assessed in terms of body surface area. Soil samples from the field indicated that (a) greatest concentrations of T. icarus occurred at about 5 cm. depth, (b) few occurred below 24 cm., the depth of the top soil, and (c) numbers of T. icarus in the top 5 cm. of soil decreased during dry periods and increased after rain. T. icarus migrates to the wet end of a moisture gradient and has maximum mobility in soil at a moisture content corresponding to field capacity and at 20° C. T. icarus survived osmotic pressure equivalent to 1 m urea for 4 days. Their oxygen consumption increased with increasing osmotic pressure but in 1 m urea there was a decline which was even more pronounced in 2 m urea. Of a population of T. icarus 35% survived for 32 weeks in soil with plants. In damp sand at 10° C, oxygen consumption was steady for 32 weeks but after 48 weeks the nematodes were dead. It is suggested that the free-living stages of plant parasitic nematodes have similar migratory habits.
On six new avian cestodes from India
Authors: Singh Kunwar Suresh
Published: June 2009

Six new species of cestodes from birds have been described. These are:Ophryocotyle indicusfrom the Rufous Babbler,Turdoides subrufus; Biuterina dicrurifrom the Grey Drongo,Dicrurus leucophaeus longicaudatus; Choanotaenia tandanifrom the Himalayan Whistling Thrush,Myiophoneus caeruleus temminckii; Choanotaenia picusifrom the Scalybellied Green Woodpecker,Picus squamatus; Panuwa stylicirrosafrom the Little Scalybellied Green Woodpecker,Picus xanthopygaeus;andAnoncotaenia indicafrom the Rufous-bellied Niltava,Muscicapa sundara.
Plasmodium bergheiandPlasmodium chabaudi chabaudi: development of simplein vitroerythrocyte invasion assays
Authors: McNally J. , O'donovan S. M. , Dalton J. P.
Published: June 2009

Erythrocyte invasion assays are described for two species of rodent malaria, namelyPlasmodium bergheiandP. c. chabaudi. These invasion assays are simple, are carried out using a candle jar and allow a number of assays to be performed simultaneously. Our results demonstrate that both rodent malaria species show anin vitropreference for reticulocytes although the preference ofP. c. chabaudifor these cells is not as marked as that ofP. berghei. The details of our invasion assays and our results obtained are discussed.
Impairment of growth of Leishmania donovani by Trypanosoma brucei during co-culture
Authors: Coppens I. , Ter Kuile B. H. , Opperdoes F. R.
Published: June 2009

Cells of Leishmania donovani in co-culture with Trypanosoma brucei, were severely affected in their growth, resulting in swelling and subsequent lysis. Similar effects were also observed when Crithidia luciliae or Phytomonas sp. were co-cultured with T. brucei. Direct contact between the cells under investigation and T. brucei was necessary because T. brucei did not hamper the growth of the other trypanosomatids, when separated by a filter with 0.2 μm pore size. Examination of this phenomenon at the ultrastructural level, in a co-culture of L. donovani and T. brucei, suggests that the plasma membrane permeability is increased in the former, as a result of a close cellular contact between the two cell types.
Theileria annulata-infected cells produce abundant proteases whose activity is reduced by long-term cell culture
Authors: Baylis H. A. , Megson A. , Brown C. G. D. , Wilkie G. F. , Hall R.
Published: June 2009

Lysates ofTheileria annulata-infected bovine lymphoblastoid cells and their uninfected counterparts were tested for protease activity using gelatin substrate SDS–PAGE. The infected cells produced a number of extra activities at pH 8·0 in the presence of Ca2+. Calcium was found to enhance the activites but was not an absolute requirement. Studies using inhibitors, including E64, 3,4-dichloroisocoumarin, pepstatin and 1, 10-phenanthroline suggested that the activities were metalloproteases. We analysed two vaccine lines; the Ode line from India and the Ankara Pendik line from Turkey. In the Ode line the later passage had very much reduced levels of the enzyme activities. In the case of the Ankara Pendik line both stages analysed had very low protease activities, but a reduction from the early to late passage was also observed. The reduction in the level of protease activity was also observed as a gradual process during on-going culture of lines derived from the Hissar and Ode stocks. In the Ode line we demonstrated a parallel decrease in the production of microschizonts upon temperature shiftin vitro.
Ultrastructural studies on the miracidium ofSanguinicola inermis(Digenea: Sanguinicolidae)
Authors: McMichael-Phillips D. F. , Lewis J. W. , Thorndyke M. C.
Published: June 2009

The miracidium ofSanguinicola inermiscontains a stylet and rodlet complex located within the single apical gland, which lies between a pair of lateral glands. The miracidial stylet consists of an arrangement of hollow tubes, composed of microtubules, connected at their base to large secretory granules and opening anteriorly through the apical papilla. A single rodlet lies adjacent to the stylet base and at least 8 rodlets are arranged at the apical tip of the stylet. The surface plasma membrane of the apical papilla is drawn into knob-like projections and 2 ciliated sensory endings are associated with the papilla. The ultrastructure of the apical gland, especially the stylet and rodlet complex, is related to the requirement for sanguinicolid miracidia to penetrate the double barrier of fish and snail hosts.
Analysis of two-dimensional protein patterns from developmental stages of the potato cyst-nematode,Globodera rostochiensis
Authors: De Boer J. M. , Overmars H. A. , Bakker J. , Gommers F. J.
Published: June 2009

Two-dimensional polyacrylamide gel electrophoresis was used to examine the differences in total protein composition between two motile stages and two sedentary stages of the potato cyst-nematode,Globodera rostochiensis. Using a sensitive silver stain, 542 reproducible protein spots were distinguished. A list of these spots is presented, showing their apparent molecular weights, estimated isoelectric points, and occurrences in the different developmental stages. When the protein patterns were compared, 401 spots were found to change their presence or size in one or more of the four developmental stages. It is therefore estimated that during the post-embryonic development ofG. rostochiensis, 74% of the polypeptides undergo modulation of their synthesis, or are affected by protein degradation or modification. In the motile stages several abundant proteins were present, which disappeared or decreased in concentration in the sedentary stages. Some of these proteins are presumably muscle proteins, and their modulation may illustrate the degeneration of body-wall musculature in the sedentary stages. It is concluded that the potato cyst-nematode has a very dynamic protein metabolism.
In vitroexcystation ofCryptosporidium parvum
Authors: Robertson L. J. , Campbell A. T. , Smith H. V.
Published: June 2009

Protocols forin vitroexcystation of oocysts ofCryptosporidium parvum, including different chemical pre-incubation steps, were compared to examine some of the biochemical triggers involved in excystation and to define anin vitroexcystation protocol of a reproducibly high efficiency. Pre-incubation steps which increased the permeability of the oocysts were found to enhance excystation dynamics and pre-treatment of oocysts with saliva was found to decrease the permeability and reduce excystation. Although excystation was maximal after incubation for 4 h, sporozoites tended to lyse over this period, and maximum sporozoite recovery occurred after 30 min. The results obtained are discussed in relation to excystation protocols adopted by different research groups and a number of recommendations are given forin vitroexcystation ofC. parvumoocysts.
Purification of an agglutinin from the haemolymph of the snail Bulinus nasutus and demonstration of related proteins in other Bulinus spp.
Authors: Harris R. A. , Preston T. M. , Southgate V. R.
Published: June 2009

The snail Bulinus nasutus 1214 possesses a potent haemagglutinin (end-point titre with human erythrocytes, 2−18) in its cell-free haemolymph which also binds to the miracidia (but not other larvae) of the incompatible parasite Schistosoma margrebowiei. We have purified a protein possessing this haemagglutinating property from the plasma of this snail. The native Mr of this protein was estimated by SDS polyacrylamide gel electrophoresis to be 210 kDa; under denaturing conditions in a 7.5% PAGE gel it ran as a major band of 135 kDa. Proteins of similar Mr were also found in the haemolymph of 16 other Bulinus spp. (the major intermediate hosts of human and veterinary schistosomiasis in Africa) although the plasma of none of these agglutinated human erythrocytes. Nonetheless, Cleveland mapping of the Mr 135 kDa bands from these different Bulinus spp. revealed 4 identical major peptide fragments (30, 28, 19 and 16 kDa) in each, thus demonstrating a similarity in the primary structure of these plasma proteins. Antisera from Balb/C mice immunized with the 135 kDa polypeptide from Bulinus truncatus 1521 cross-reacted in Western blots with the 135 kDa band of other members of the same truncatus/tropicus species complex but not with species from the africanus or forskalii species groups.