bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of intra-erythrocytic magnesium ions on invasion byPlasmodium falciparum
Authors: Field S. J. , Rangachari K. , Dluzewski A. R. , Wilson R. J. M. , Gratzer W. B.
Published: June 2009

Exclusion of magnesium ions from resealed ghosts or their extraction from intact human red cells by means of an ionophore results in a reversible drop in susceptibility to invasion byPlasmodium falciparummerozoitesin vitro. Resealed ghosts, containing magnesium-ATP and diluted cytosol, are invaded with high efficiency only when the original hypotonic lysis is carried Out in the presence of magnesium ions. This effect is not related to the loss of membrane-associated constituents when magnesium ions are absent. Ghosts containing calcium ions, together with the protective agent, flunarizine, were essentially resistant to invasion; this effect is again at least partially reversible. A possible explanation of these phenomena is that entry of the merozoite may be inhibited by breakdown of the host cell phospholipid asymmetry, with the appearance of aminophospholipids at the outer cell surface.
A kinetoplast DNA probe diagnostic for Leishmania infantum
Authors: Gramiccia M. , Smith D. F. , Angelici M. C. , Ready P. D. , Gradoni L.
Published: June 2009

A 196 bp fragment of cloned kinetoplast (k) DNA of Leishmania infantum has been sequenced and shown to be diagnostic for this species. The DNA from 104–105 promastigotes was routinely and specifically detected in crude dot blots of whole cells lysed in situ, and there was no cross-hybridization with 106 cells of L. major, L. tropica, L. killicki, L. aethiopica, L. braziliensis and L. mexicana. A low degree of hybridization was found with L. donovani and L. chagasi. This probe will be of particular use in Mediterranean countries, such as Italy, in which dermotropic zymodemes of L. infantum can be difficult to isolate and grow in numbers sufficient for isoenzyme typing.
Seasonal occurrence and maturation of Triaenophorus nodulosus (Pallas, 1781) (Cestoda: Pseudophyllidea) in the Pike Esox lucius L. of Llyn Tegid
Authors: Chubb James C.
Published: June 2009

1. An account is given of the seasonal occurrence and maturation of Triaenophorus nodulosus, based on the examination of the worms from 104 pike taken in Llyn Tegid from December 1957 to October 1959.

2. The plerocercoids of T. nodulosus were found in the livers of the perch of Llyn Tegid. Infective plerocercoids were found throughout the year, and it is considered that invasion of the pike, also, occurred throughout the year.

3. The annual cycle of maturation of T. nodulosus described by other workers is confirmed. Currently, five arbitrary stages of maturity were recognized, and the incidence of each of these stages during each month of the investigation is given. During June to September the worms were of plerocercoid-form, from October to December genital development occurred and the first eggs were observed in the uteri in December. Egg liberation was at a peak from April to May, and by June the population of matured worms was lost.

4. A non-linear relationship was found between the length of the pike and the numbers of worms occurring in the intestines of these fish. This phenomenon was related to the feeding habits of the pike; the medium-sized most heavily infected pike were eating the largest number of the perch containing the plerocercoids.

5. It was found that although invasion of the pike by plerocercoids of T. nodulosus occurred throughout the year, there was no increase in the numbers of worms in the pike intestines, to a maximum, at any time of the year, rather there was a more or less constant number of worms in pike of given length at all times of the year. It is suggested, therefore, that a dynamic equilibrium exists between gain of plerocercoids and loss of worms from the pike intestines at all times.

6. Factors affecting the change from plerocercoid to a mature worm are discussed. It is suggested that an experimental approach is needed.

I am grateful to the Welsh Land and Agricultural Sub-Commission for permission to net Llyn Tegid, and to Captain G. H. A. Boyle of the Sub-Commission for his help in the capture of the pike. I also wish to thank Professor R. J. Pumphrey in whose Department this work was carried out, Dr P. M. Sheppard for statistical analyses, Dr J. W. Jones and Mr S. Prudhoe (British Museum, Natural History) for discussion of the manuscript. The work was carried out during the tenure of a Department of Scientific and Industrial Research studentship.
The attachment of the monogenean Diplozoon paradoxum to the gills of Rutilus rutilus L. I. Micro-habitat and adhesive attitude
Authors: Owen I. L.
Published: June 2009

Both individuals of a pair of Diplozoon paradoxum Nord., 1832, when parasitizing the gills of Rutilus rutilus, are normally attached to the same hemibranch but never to the same surface of one primary lamella. A preference is shown for attachment to certain gills and also to particular locations on the gills.

Diplozoon paradoxum displays asymmetry of its haptor when attached to the gills of the roach but the haptor assumes bilateral symmetry when unattached. As in Discocotyle, this impermanent asymmetry is facultative to the left or right, dependent upon the incidence of the gill-ventilating current, so that the body of a worm will present the least amount of resistance to the water as it passes across the gills. It is probable that impermanent, facultative asymmetry occurs in other species of the genus Diplozoon, and the usefulness of the asymmetrical nature of the haptor as a taxonomic criterion is therefore extremely limited.

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. I am indebted to Mr D. Haigh for supplying me with fishes. This work was done while receiving a grant from the Department of Scientific and Industrial Research.
Studies on monocystid gregarines
Authors: Rees B.
Published: June 2009

The present paper is concerned with the description of six species of gregarines which are all parasites of British earthworms; they are: Apolocystis herculea (Bosanquet, 1894), A. lavernensis sp.nov., A. perfida sp.nov., A. rotaria sp.nov., A. spinosa sp.nov., A. villosa (Hesse, 1909) Cognetti, 1923. The observations upon which these descriptions are based form part of a larger survey of the monocystid fauna of several British earthworm species from the Cardiff area. The methods used are fully described in a previous paper (Rees, 1962).
Pathology of fatal and resolvingPlasmodium bergheicerebral malaria in mice
Authors: Neill A. L. , Hunt N.H.
Published: June 2009

CBA/T6 and Balb/c mice inoculated withPlasmodium bergheiANKA strain (PbA) died from cerebral malaria 6–8 days post-inoculation. DBA/2J mice similarly inoculated developed a non-fatal cerebral malaria, with mild temporary cerebral symptoms, and died between days 15 and 22 from other malaria-related complications. When inoculated withP. bergheiK173 (Pb) these mouse strains did not develop a cerebral malaria but died between days 15 and 22 from other malaria-related complications. These mouse strain/parasite strain combinations allow for detailed examination of factors critical in the pathology of murine cerebral malaria. Monastral Blue, a colloid dye, when injected intravascularly between days 0 and 2 into PbA-inoculated CBA (PbA-CBA) or Balb/c (PbA-Balb/c) mice prevented death from cerebral malaria. There was no evidence of increased vascular permeability at this stage. When Monastral Blue was injected between days 5 and 8, there was increased vascular permeability in the kidney, liver, lung, spleen and brain of PbA-CBA and PbA-Balb/c mice. Injection of Monastral Blue into these animals at this time also precipitated cerebral symptoms and death, but not in Pb-infected mice. Endothelial and mononuclear cells phagocytosed, and were coated with, the Monastral Blue particles when the dye was injected between days 5 and 8 into PbA-CBA and PbA-Balb/c mice. Control, uninfected mice did not demonstrate either of these features. Pb-infected mice only demonstrated coated mononuclear cells. Mononuclear cell attachment to the endothelium, increased vascular permeability and increased association of Monastral Blue particles with monocytes and endothelial cells were correlated with cerebral symptoms and death. Monastral Blue is thus a useful agent for studying the roles of mononuclear cells and endothelium in murine cerebral malaria.
Unique ultrastructural adaptations of Pseudodiplorchis americanus (Polystomatidae: Monogenea) to a sequence of hostile conditions following host infection
Authors: Cable J. , Tinsley R. C.
Published: June 2009

The polystomatid Pseudodiplorchis americanus occupies a wider range of habitats and experiences more diverse physiological conditions than any other monogenean. It initially invades the respiratory system of an anuran, Scaphiopus couchii, and then migrates along the alimentary tract while the host is actively feeding, resulting in exposure to digestive enzymes and the surfactant action of bile. Whilst in the urinary bladder, parasites are exposed to wide osmotic fluctuations. This ultrastructural study reveals a set of adaptations unknown elsewhere in platyhelminth biology. During development within the respiratory tract, pre-migratory worms accumulate two types of electron-dense tegumental vesicle. Migration through the gut is accompanied by mass secretion of vesicles which appear to provide protection against digestion. Pre-migrants transferred experimentally to digestive fluids die within minutes unless they have received a specific cue which is responsible for triggering vesicle secretion. Migrants stimulated by this trigger factor can tolerate the same conditions for up to 8 h by continually releasing vesicles to form a protective surface coat. No specific structural adaptations were evident for survival in the lungs or bladder of the host.
Entomopathogenic nematode host finding: response to host contact cues by cruise and ambush foragers
Authors: Lewis E.E. , Gaugler R. , Harrison R.
Published: June 2009

Search behaviour of two entomopathogenic nematode species with different foraging strategies was compared by measuring parameters of unrewarded search after contact with host cues. Steinernema glaseri cruises in search of hosts. Steinernema carpocapsae ambushes hosts. Nematodes should respond to contact with relevant host cues by shifting their search from ranging to localized after contact with them. We predicted that cruising foragers rely on chemical cues more heavily than ambushers. These species were also tested for host affinities. Nematodes were tracked by image analysis after exposure to faeces, cuticle or food of either Popillia japonica or Spodoptera exiqua. Steinernema glaseri responded to selected host cues by shifting from ranging to localized search, characterized by decreased locomotory rate, distance travelled, search area and the proportion of the test period spent moving. Steinernema carpocapsae did not respond to host cues. Steinernema glaseri responds to selected chemical host cues for host location, whereas S. carpocapsae does not.
Schistosomes fromHippopotamus amphibiusL. II. The morphology ofSchistosoma edwardiensesp.nov.
Authors: Thurston June P.
Published: June 2009

The morphology of the adult blood flukeSchistosoma edwardiensesp.nov. fromHippopotamus amphibiusL. is described and compared with that of other species ofSchistosoma.

I wish to acknowledge the receipt of a research grant from Makerere University College towards expenses incurred during this work. I should like to thank Captain F. Poppleton, Warden of the Queen Elizabeth National Park, Dr R. M. Laws, Nuffield Unit for Tropical Animal Ecology, and Dr W. M. Longhurst, University of California, for helping me to get specimens from the hippopotami, also Mr L. Rugema, histologist, for sectioning the worms.
Nuclear division inEntamoeba invadensRodhain, 1934
Authors: Narasimhamurti C. C.
Published: June 2009

1. Examination of dividing trophozoites ofE. invadensrevealed that the peripheral granules did not contribute directly to the formation of chromosomes. Material for the chromosomes seemed to be derived from the karyosome and the perikaryosomal particles. No centrioles and spindle mechanism were noticed.

2. The nucleus showed Feulgen-positive material at all stages; in the interphase the reaction was faint because of the poor staining of the karyosome and widely dispersed perikaryosomal particles. The intensity of the staining reaction increased with the onset of division and continued so till late anaphase.

3. Nuclear division in the cyst was found to be different from that of the trophozoites and involved the formation of a typical spindle.

4. Karyosomes of the nuclei of the uni-, bi-, tetra-nucleate cysts were all positive to Feulgen staining.

5. Observations on amoebae undergoing cytokinesis showed that the process of division supports the amoeboid movement theory of cleavage put forward by Chalkley (1935, 1951).

Thanks are due to Dr P. Tate for constant guidance and encouragement during the course of this work and to Dr E. W. McConnachie for kindly giving the cultures and for critically reading through the manuscript. The work was carried out during the tenure of a Royal Society and Nuffield Foundation Commonwealth Bursary.
Observations on the gregarine Rotundula gammari (Diesing, 1859), Goodrich, 1949
Authors: Narasimhamurti C. C.
Published: June 2009

1. A local population of Gammarus pulex, infected with Heliospora longissima and Rotundula gammari, was found to have an intracellular developmental stage.

2. Experimental infections of G. pulex were made with the two species of gregarines. In the case of R. gammari infections, large numbers of intracellular developmental stages were found.

3. The taxonomic relationship of the genera Cephaloidophora and Rotundula is discussed.

Thanks are due to Dr P. Tate for constant encouragement and guidance during the course of this work and for the many helpful suggestions in the preparation of the manuscript. Thanks are also due to Mr D. W. T. Crompton for kindly giving me the infected material. The work was completed during the tenure of a Royal Society and Nuffield Foundation Commonwealth Bursary.
Assessment of parasite population dynamics in mixed infections of rodent plasmodia
Authors: Snounou G. , Bourne T. , Jarra W. , Viriyakosol S. , Wood J. C. , Brown K. N.
Published: June 2009

Cloned lines of the four rodentPlasmodiumspecies can be differentiated by the RFLP pattern generated following Southern blotting and probing with PCsv4.1, a probe derived from aP. chabaudi chabaudigenomic library. Groups of CBA/Ca mice were inoculated simultaneously with cloned lines from two parasite species or strains. Six mixed species and three mixed strain infections using rodent malaria lines were initiated. The composition of the parasite population in each group was determined qualitatively and semi-quantitatively by analysis of the DNA purified from daily blood samples, thereby providing a dynamic representation of each mixed infection. Effects on the course of parasitaemias are presented and discussed.
Selection of specific genotypes ofgiardia intestinalisby growthin vitroandin vivo
Authors: Andrews R. H. , Chilton N. B. , Mayrhofer G.
Published: June 2009

This study examined whether allelic changes observed when clinical isolates ofGiardia intestinalismade in suckling mice were adapted toin vitrogrowth occurred as a result of gene switching (alternate isoenzymes) or through selection of organisms with different genotypes from mixed infections. Samples were compared electrophoretically at 20 enzyme loci. Marked allelic differences were detected between the uncloned clinical isolates grown in mice and the axenic cultures established from them. Furthermore, the allelic profiles of the uncloned isolates changed during the course ofin vivoorin vitrogrowth. In contrast, all clones produced from each isolate retained identical allelic profiles, regardless of whether they were grownin vivoorin vitro. These findings argue against gene switching as an explanation for the observed allozyme changes and support preferential selection of organisms with specific genotypes by growth conditions. The data indicate the presence of at least 2 and possibly up to 4 distinct genotypes within each clinical isolate. The genetic differences detected between clinical isolates in suckling mice were of similar magnitude to those that separate different axenic isolates ofG. intestinalisinto cryptic species. Conversely, the genetic differences between the isolates were limited when sampled after establishmentin vitro. These findings have significant implications for research onGiardiaand other medically important parasites and raise the possibility that culture may exert a similar selective bias on the genotypes isolated from infections with other parasitic protozoa.
Trichobilharzia ocellata infections in its snail host Lymnaea stagnalis: an in vitro study showing direct and indirect effects on the snail internal defence system, via the host central nervous system
Authors: Amen R. I. , De Jong-Brink M.
Published: June 2009

In this in vitro study we investigated whether previously described in vivo plasma-associated effects, that occurred in the period shortly after penetration of Trichobilharzia ocellata into the snail host Lymnaea stagnalis (1.5–72 h post-exposure; p.e.) were direct and/or indirect effects of parasite-derived factor(s). It was investigated whether the effect is mediated by the central nervous system (CNS) of the host. Phagocytic activity of the haemocytes was taken as a parameter for the activity of internal defence of the host. A number of preliminary experiments were performed. When the supernatant of in vitro cultured parasites (33 h; corresponding with their developmental stage in vivo when plasma-associated activation was found) was applied directly to monolayers of haemocytes, it appeared to enhance their phagocytic activity. No direct effect, however, was found with a supernatant of parasites cultured for a longer period of time (72 h; when, in vivo, a plasma-associated suppression was found). In this case, indirect suppression was detected: the parasites appeared to have released a factor that induced the CNS of the host to release material suppressing the activity of the internal defence system of the host. To date the nature of this factor is unknown.
Population dynamics of Sphaerospora dicentrarchi Sitja-Bobadilla et Alvarez-Pellitero, 1992 and S. testicularis Sitja-Bobadilla et Alvarez-Pellitero, 1990 (Myxosporea: Bivalvulida) infections in wild and cultured Mediterranean sea bass (Dicentrarchus labrax L.)
Authors: Sitja-Bobadilla A. , Alvarez-Pellitero P.
Published: June 2009

The population dynamics of Sphaerospora dicentrarchi and S. testicularis, myxosporean parasites of sea bass (Dicentrarchus labrax), was studied in different groups of cultured and wild fish. S. dicentrarchi prevalence was higher for wild fish (100%) than for cultured ones (70.5%). Infection levels increased with host age and there were no significant sex differences in cultured fish. Among parasitized organs, the gall bladder and intestine registered the highest infection levels in wild and cultured fish. A progressive increase in infection levels of S. testicularis was observed in cultured males during the spawning season in four consecutive periods. The evolution of the percentage of the different parasitic stages is pointed out. The infection seems to be related to water temperature and gonadal maturation.
Assessment of monoclonal antibodies toEchinococcus granulosusAntigen 5 and Antigen B for detection of human hydatid circulating antigens
Authors: Liu D. , Rickard M. D. , Lightowlers M. W.
Published: June 2009

Four monoclonal antibodies (MAb) toEchinococcus granulosusAntigen 5 (Ag5) and Antigen B (AgB) were assessed in an enzyme-linked immunosorbent assay (ELISA) for detection of circulating antigens (CAg) in sera of human patients withE. granulosusinfection. Around 5·5–8% of 200 sera from 42 surgically proven hydatid patients contained detectable CAg by individual MAb. The combined detection rate for CAg, using four MAb, was 19% (38/200). Although hydatid CAg was detected by MAb in at least one serum sample from 21 of 42 patients, some patients remained negative in the assay regardless of the time when serum samples were taken (pre- or post-operatively), or of the continuing presence of hydatid cysts, their location or fertility. In addition, it was observed that the binding capacity of MAb for sheep hydatid cyst fluid antigen (SHCF) was somewhat reduced in the presence of normal human serum. The CAg detection assay would only be useful for assessment of hydatid infection status in patients with detectable CAg in serum samples.
A comparison of African Buffalo, N'Dama and Boran cattle as reservoirs of Trypanosoma vivax for different Glossina species
Authors: Moloo S. K. , Gettinby G. , Olubayo R. O. , Kabata J. M. , Okumu I. O.
Published: June 2009

Teneral Glossina morsitans centralis were fed on the flanks of African buffalo, N'Dama or Boran cattle infected with Trypanosoma vivax IL 2337. The infected tsetse were maintained on goats and on day 25 after the infected feed, the surviving tsetse were dissected to determine the infection rates. The mean mature infection rates (% ± S.E.) in the tsetse fed on buffalo, N'Dama and Boran cattle were 34·3 ± 9·9, 33·7 ± 13·4 and 58·9 ± 7·1, respectively. Logistic regression analysis indicated that infection rates in the labrum and hypopharynx of the tsetse were significantly lower when fed on the infected buffalo or N'Dama than Boran cattle. Similarly, the risk of infection was significantly lower in male than female tsetse. When teneral G. m. centralis, G. pallidipes, G. p. gambiensis, G. brevipalpis and G. longipennis were fed simultaneously on either the buffalo cow, the N'Dama bull or the Boran steer infected with T. vivax IL 2337, the mature infection rates were higher in the two morsitans group than the two fusca group tsetse, whilst G. p. gambiensis was relatively refractory to the infection, irrespective of the host species on which they fed. Logistic regression analysis indicated that the infection rates in the labrum and hypopharynx were significantly different amongst the five tsetse species for each of the three infected host animals. Nevertheless, the trypanotolerant African buffalo and N'Dama cattle may serve as reservoirs of T. vivax infection as can trypanosusceptible Boran cattle.
Interactions between chemotherapy and immunity in bovine theileriosis
Authors: Cox F. E. G.
Published: June 2009

In bovine theileriosis the use of chemotherapy to control an infection sufficiently long to permit the establishment of a solid protective immune response has been developed as a routine vaccination procedure. Infections withTheileria parvaandT. annulatacan be prevented by the administration of carefully controlled numbers of sporozoites simultaneously with a long acting tetracycline and this form of immunization has been widely used for the control of East Coast fever in Africa with considerable success. In this review, the nature of the chemotherapy, the immune response and the interactions between chemotherapy and immunity in the development of infection-and-treatment immunization procedures are discussed.
Hypothesis: impaired immunity as a factor which contributes to the spread of drug-resistance
Authors: Doenhoff M. J. , Davies A. J. S.
Published: June 2009

Evidence has accrued to indicate that host defence mechanisms enhance the efficacy of many of the drugs used to treat infectious diseases. Because of this, and also because of the likelihood of increased pathogen loads in immunoincompetent hosts, some infections are less likely to be completely cured by normal regimens of chemotherapy in individuals with drastically impaired immune responsiveness. In such circumstances natural selection could result in the accelerated emergence of drug-resistant pathogens.
Proteins on the surface of the malaria parasite and cell invasion
Authors: Holder A. A.
Published: June 2009

The malaria parasite exists in an extracellular form at several stages in its life cycle. Within the vertebrate host, sporozoites and merozoites have to invade specific cell types. Proteins on the surface of the parasite or externalized from specialized organelles have been implicated as ligands for receptors on the host cell surface. Direct binding studies have identified parasite proteins that interact with the target cell surface. Examination of the deduced amino acid sequences has allowed the identification of primary structural motifs which may have roles in this process. On the sporozoite, the circum-sporozoite protein and sporozoite surface protein-2, a protein initially located within micronemes, have been found to contain an amino acid sequence thought to be involved in mediating recognition of sulphated polysaccharides on the surface of a liver cell. On the merozoite, merozoite surface protein-1 may be involved in the initial recognition of red blood cells; this protein undergoes a complex series of modifications in the time between its synthesis as a precursor molecule and successful erythrocyte invasion. Other merozoite proteins located at the apical end of the parasite have been identified as erythrocyte or reticulocyte binding proteins.
Lung-worms (Nematoda: Pseudaliidae) of harbour porpoises (Phocoena phocoena) in Norwegian waters: patterns of colonization
Authors: Balbuena J. A. , Aspholm P. E. , Andersen K. I. , Bjørge A.
Published: June 2009

We studied the component community of lung-worms of the harbour porpoise, attempting to establish the relative importance of ecological and evolutionary factors on its development. The lungs of 64 porpoises by-caught in Norwegian waters were examined for helminths. Three pseudaliid species were detected. The porpoises appear to be readily colonized by lung-worms, the structure of the component community of calves being fairly similar to that of the remainder. Prenatal and/or transmammary infections might partly account for these early infections. However, host age was correlated with the number of lung-worm species, suggesting that the lung-worms may have heteroxenous cycles similar to other metastrongyloids. The lung-worm species tended to co-occur more often than expected by chance. This pattern is commonly observed in communities formed by phylogenetic relatives. Mean species richness of lung nematodes differed significantly among mammalian orders. However, species richness of marine species seemed very similar to those of most terrestrial species. This evidence suggests that phylogenetic factors seem more important than ecological ones in determining the number of lung-worm species in mammals.
The relationship between pattern and scale in parasite communities: a stranger in a strange land
Authors: Kennedy C. R. , Bush A. O.
Published: June 2009

Problems of pattern and scale are considered in relation to helminth communities of freshwater fish by examining them at different hierarchical taxonomic and spatial scales, with a view to seeking generalizations of heuristic value, assessing the importance of phylogenetic and ecological determinants of community structure and improving understanding of unpredictable communities. Initially, communities were analysed at the level of salmonid genera, focusing onOncorhynchus, in its heartland in Canada: then inO. mykissthroughout its global range and finally in individual localities to which it has been introduced in Britain. In the heartland, communities are dominated by salmonid specialist helminths, forming a phylogenetic element: the minority ecological element comprises broad generalists and non-salmonid specialists. Most species except generic specialists are shared between host genera. As the distance to whichO. mykisswas translocated from its heartland increases, so generic specialists disappear first and then salmonid specialists decline. The community is thus increasingly composed of generalists and it also becomes increasingly poor. Helminths may be acquired from native salmonids and/or unrelated hosts, depending on availability. This same pattern is paralleled in individual localities in a restricted region: the phylogenetic element reflects the native salmonid species present and the ecological element the presence of other genera of fish, i.e. a supply-side situation. The change of scale in analysis has thus enabled the recognition of generalizations and patterns of heuristic value and improved the understanding of unpredictable communities by interpreting local variation as ecological ‘noise’ that often obscures fundamental patterns. In this and other taxa of fish, phylogenetic elements dominate helminth communities in the heartlands, but ecological elements dominate as the host increasingly becomes a stranger in a strange land.
Turnover of microfilariae in small mammals 2. Disintegration of microfilariae (Acanthocheilonema viteae) (Filarioidea: Nematoda) after intravenous injection into the jird,Meriones unguiculatus
Authors: Wenk P. , Kellermann E. , Hafner C.
Published: June 2009

After i.v. injection of 305 × 103microfilariae (mf) per animal (50 g) into naive jirds, 50·8% of them could be recovered at autopsy 15 min later. Of these, 65·8% were calculated to be in the peripheral circulating blood (PCB) and were completely intact; 18·6% were recovered by perfusion of the lungs and 13·6% from the liver. In both organs about half the mf were associated with adherent lymphocytes and neutrophils but a few were partly disintegrated. Only 2·6% were recovered from the kidneys and the spleen. In long-term injection experiments using the same inoculum size the autopsy was done 15 min and 1, 3 and 6 weeks post-injection (p.i.) of mf into naive jirds. Throughout the experimental period the density of mf remained more or less constant in the PCB, but 3 weeks p.i. the density in the lungs increased up to 14 times to that in the PCB, whereas in the liver it decreased at the same time to a density similar to that in the PCB. In patent animals with adult worms delivering mf these were distributed as follows: 34·7% were calculated to be in the PCB; 24·4% were obtained by perfusion from the lungs and 22·0% from the liver; the rest were found in the kidneys (16·6%) and spleen (2·3%). In the lungs and the liver about 5/6 were associated with adherent cells, partly disintegrated or as fragments. In view of the fact that very few mf become disintegrated immediately after i.v. injection and also from their extremely long sojourn in the PCB, a low turnover rate of mf is presumed. The limited fecundity of the female adults combined with the 20 weeks median circulation time of injected mf in the PCB supports this view.
Molecular characterization ofTheileriaparasites: application to the epidemiology of theileriosis in Zimbabwe
Authors: Bishop R. P. , Spooner P.R. , Kanhai G. K. , Kiarie J. , Latif A. A. , Hove T. , Masaka S. , Dolan T. T.
Published: June 2009

FortyTheileriaschizont-infected lymphocyte culture isolates from Zimbabwe were characterized using a panel of antischizont monoclonal antibodies (MAbs) and 4Theileria parvaDNA probes containing cloned extrachromosomal element,Tprrepetitive, ribosomal and telomeric sequences. TheTheileriaisolates were assigned asT. parvaorT. taurotragion the basis of reactivities with MAbs and restriction fragment length polymorphisms (RFLPs) detected using the extra chromosomal element probe. Cattle-derivedT. parvaisolates were relatively homogeneous on the basis of reactivities with MAbs and RFLPs detected usingTprrepetitive and ribosomal DNA probes. In contrast to previous results from Kenya, most of the cattle-derived isolates from Zimbabwe exhibited very similarTprrestriction fragment patterns, although theTprgenotypes of buffalo-derived isolates were heterogeneous. This suggests that selection for a particularTprgenotype may be occurring in cattle. Many isolates with similarTprgenotypes were differentiated by RFLPs detected using the telomeric DNA probe. TheT. parvaBoleni immunizing stock was distinguished from all other isolates by telomeric RFLPs. TheT. parvaBoleniTprrepetitive DNA probe cross-hybridized withT. taurotragiDNA and detected RFLPs between differentT. taurotragiisolates.
Cleavage of immunoglobulin G by excretory–secretory cathepsin S-like protease ofSpirometra mansoniplerocercoid
Authors: Kong Y. , Chung Y.-B. , Cho S.-Y. , Kang S.-Y.
Published: June 2009

When immunoglobulin G (IgG) was incubated withSpirometra mansoniplerocercoid (sparganum), it was cleaved into Fab and Fc fragments. Fab/c fragments were also hydrolysed. The digestion was accelerated by dithiothreitol (DTT), indicating that cleavage of IgG heavy chain was due to a cysteine protease secreted into the medium. The responsible enzyme, ofMr27 (± 0·8) kDa, was purified by a series of thiopropyl affinity, Sephacryl S-300 HR and DEAE-anion exchange chromatographies, either from worm extracts or from excretory–secretory products (ESP). The purified, thiol-dependent protease showed an optimal activity at pH 5·7 with 0·1 M sodium acetate but was active over the pH range 4·5–8·0. Its activity was inhibited completely by 10−5M L-trans-epoxysuccinylleucylamido(4-guanidino) butane (E-64) and 1 mM iodoacetamide (IAA), but by only 53% using the specific cathepsin L inhibitor, Z-Phe-Phe-CHN2(5 × 10−5M). Partial NH2-terminal amino acid sequence was Leu-Pro-Asp-Ser-Val-Asn-Trp-Arg-Glu-Gly-Ala-Val-Thr-Ala-Val which showed 80% homology to human cathepsin S. Immunoblot analysis showed that sera from infected patients exhibited IgE antibody reaction. It is proposed that cleavage of immunoglobulin by an excreted–secreted, cathepsin S-like, allergenic protease is a mechanism of immune evasion used by the sparganum.
Contractile protein system in the asexual stages of the malaria parasite Plasmodium falciparum
Authors: Webb S. E. , Fowler R. E. , O'Shaughnessy C. , Pinder J. C. , Dluzewski A. R. , Gratzer W. B. , Bannister L. H. , Mitchell G. H.
Published: June 2009

F-actin was detected in asexual-stage Plasmodium falciparum parasites by fluorescence microscopy of blood films stained with fluorescent phalloidin derivatives. F-actin was present at all stages of development and appeared diffusely distributed in trophic parasites, but merozoites stained strongly at the poles and peripheries. No filament bundles could be discerned. A similar distribution was obtained by immunofluorescence with 2 polyclonal anti-actin antibodies, one of which was directed against a peptide sequence present only in parasite actin (as inferred from the DNA sequence of the gene). A monoclonal anti-actin antibody stained very mature or rupturing schizonts but not immature parasites. Myosin was identified in immunoblots of parasite protein extracts by several monoclonal anti-skeletal muscle myosin antibodies, as well as by a polyclonal antiserum directed against a consensus conserved myosin sequence (IQ motif). The identity of the polypeptides recognized by these antibodies was confirmed by overlaying blots with biotinylated F-actin. The antiserum and one of the monoclonal antibodies were used in immunofluorescence studies and were found to stain all blood-stage parasites, with maximal intensity towards the poles of merozoites. Our results are consistent with the presence of an actomyosin motor system in the blood-stage malaria parasite.
Description of a simulation model for the population dynamics ofEimeria acervulinainfection in broilers
Authors: Henken A. M. , Ploeger H. W. , Graat E. A. M. , Carpenter T. E.
Published: June 2009

A simulation model for the population dynamics ofEimeria acervulinainfection in broilers is presented. The model describes the development of the numbers of parasites in the various life-stages during the growing period of broilers and the empty house period between grow-outs. The model includes assumptions with respect to development of immunity toE. acervulinainfection and effects of application of anticoccidial drugs. The model consists of a set of difference equations that are solved numerically at 1 h intervals. Under constant conditions, an equilibrium level was reached after a few grow-outs during which infection always peaked around the 21st day in the growing period. Within a growing period, infection peaked earlier (later) than the 21st day in case initial numbers of sporulated oocysts were higher (lower) than the equilibrium number.
Characterization of Theileria parva which infects waterbuck (Kobus defassa)
Authors: Stagg D. A. , Bishop R. P. , Morzaria S. P. , Shaw M. K. , Wesonga D. , Orinda G. O. , Grootenhuis J. G. , Molyneux D. H. , Young A. S.
Published: June 2009

Theileria-free waterbuck (Kobus defassa) born in captivity were successfully infected with Theileria parva sporozoites derived from ticks infected by feeding on African buffalo (Syncerus caffer). All waterbuck underwent mild infections with the development of sporadic schizont and piroplasm parasitosis when inoculated with sporozoite doses lethal to cattle. A carrier state of T. parva was demonstrated by feeding clean R. appendiculatus nymphs on two of these infected waterbuck. Tick batches from these waterbuck on 2 of 5 occasions transmitted lethal Theileria infections to cattle. In a separate experiment, waterbuck cells were infected and transformed in vitro by T. parva sporozoites derived from buffalo but not by cattle-derived T. parva (Muguga) sporozoites. Waterbuck cells infected in vitro with T. parva isolated from buffalo were inoculated into autologous waterbuck but no infections developed. Theileria parva isolates generated in this study from various sources were characterized using anti-T. parva schizont monoclonal antibodies (MAbs), and it was found that buffalo-derived and waterbuck-passaged isolates had different profiles. Species-specific synthetic oligonucleotide probes, restriction fragment length polymorphism (RFLP) analysis with cloned T. parva DNA probes, and DNA sequence analysis of the p67 sporozoite antigen gene confirmed that the waterbuck-passaged parasite was T. parva. The Tpr repetitive probe hybridization patterns from the waterbuck-passaged parasites were different from the other samples tested. The ribosomal genotype of the waterbuck-passaged T. parva was similar to that of cattle-derived T. parva Muguga. Analyses with both probes and MAbs suggested that a minor parasite population present within the T. parva 7014 buffalo- derived stock had been selected during waterbuck passage. A variable region of the p67 sporozoite antigen gene of the waterbuck-passaged T. parva was similar to that of cattle-derived T. parva stocks and different from that of buffalo- derived parasites. Based on these results, methods were suggested to confirm and quantitate the involvement of waterbuck in the epidemiology of cattle theileriosis.
Ultrastructural localization of pancreatic polypeptide- and FMRFamide immunoreactivities within the central nervous system of the nematode, Ascaris suum (Nematoda: Ascaroidea)
Authors: Brownlee D. J. A. , Brennan G. P. , Halton D. W. , Fairweather I. , Shaw C.
Published: June 2009

A post-embedding immunogold technique has been used to examine the subcellular distribution of immunoreactivities to vertebrate pancreatic polypeptide (PP) and to the invertebrate peptide, FMRFamide within the central nervous system (CNS) of the nematode, Ascaris suum. Gold labelling of peptide was localized exclusively over dense-cored vesicles within nerve cell bodies, nerve axons and nerve terminals of the main ganglia and nerve cords in the CNS. Double-labelling of peptides demonstrated an apparent co-localization of PP and FMRFamide immunoreactivities in the same dense-cored vesicles, although populations of dense-cored vesicles that labelled solely for FMRFamide were also evident. Antigen preabsorption studies indicated little or no cross-reactivity between the two antisera.
Infection of dogs by Toxocara canis carried by flies
Authors: Pegg Elizabeth J.
Published: June 2009

Attempts were made to infect Stomoxys calcitrans, Lucilia sericata and Musca domestica with embryonated eggs of Toxocara canis and Toxascaris leonina. Only Musca domestica was successfully infected with Toxocara canis eggs.

Six Beagle pups were given anthelmintic treatment and infected flies were then fed to five of them. The five pups were examined at varying intervals, the sixth being used as a control. Four of the experimentally infected pups showed evidence post-mortem of having become infected with Toxocara canis by the ingestion of Musca domestica. Larvae of Toxocara canis were recovered from several tissues. Immature and adult forms were recovered from the intestinal contents. The results suggest that flies of Musca domestica are not only a source of infection to the dog, but that they may be of importance in the spread of toxocariasis in man.

I would like to thank Professor A. O. Betts and Dr W. P. Beresford-Jones for their encouragement and helpful criticism and also Mr G. Yeoman and Mr B. C. Warren of Beecham Research Laboratories, Wheathampstead, for their assistance and for the supply of flies. I am also very grateful to Mr and Mrs D. Appleton, Carmarthenshire, Wales for their co-operation in treating and supplying the beagle pups.
Analysis of a new genetic cross between two East African Trypanosoma brucei clones
Authors: Schweizer J. , Pospichal H. , Hide G. , Buchanan N. , Tait A. , Jenni L.
Published: June 2009

Two clones of East African Trypanosoma brucei, with distinct homozygous isoenzyme patterns for one of three enzymes examined, were cotransmitted through the tsetse fly vector Glossina morsitans centralis. Flies with mature infections were individually fed on mice and the subsequent bloodstream form populations analysed for the presence of hybrid trypanosomes by isoenzyme analysis. Several combinations have previously been detected using this approach (Schweizer, Tait & Jenni, 1988; Sternberg et al. 1989). Four clones were isolated from one of the hybrid-containing populations. They showed a hybrid phenotype, as would be expected for the F1 progeny in a diploid Mendelian system. The analysis of the progeny clones, using two gene probes which detect restriction fragment length polymorphisms between the two parental stocks, showed that alleles had segregated at each locus and given rise to three different non-parental combinations of alleles in the hybrid progeny. Characterization of the hybrid progeny clones by PFGE (pulsed field gradient gel electrophoresis) revealed that all progeny clones were recombinant for the intermediate size chromosomes. From the analysis of the segregation of the larger chromosomes, marked by P0K (phosphoglycerate kinase) and CP (cysteine protease) gene probes, it was inferred that the progeny clones did not result from a direct fusion of diploid cells. Results with the PGK probe fit into a classical system with meiosis and subsequent fusion of the nuclei to form diploid progeny. On the other hand, blots with the CP probe as well as some of the ethidium bromide stained PFGE gels revealed the existence of non-parental size chromosomes in some of the hybrid progeny. This phenomenon was observed previously (Gibson, 1989) and further investigation is required to elucidate the mechanism.
Neuropeptides and their evolution
Authors: Shaw C.
Published: June 2009

Neuropeptides are ubiquitous signalling molecules in all metazoans possessing nervous systems, from the simple nerve nets of the cnidarians to the immensely complex systems of mammals. While the discipline of peptide neuroendocrinology was born through the study of higher vertebrates, there now exists a plethora of information regarding neuropeptides and peptidic regulatory factors in invertebrates. Such phylogenetic studies have revealed that peptidic neurotransmission is of early evolutionary origin and that, while invertebrates have nervous systems which are simpler in terms of nerve cell number and organisation when compared with vertebrates, the complexity of the peptidic ‘vocabulary’ of invertebrate neurones is of a similar order of magnitude. Most research on invertebrate neuropeptides has been directed towards representative members of groups such as the insects and molluscs and it is only in recent years that efforts have been focused on the helminths (platyhelminths and nematodes). Here, the putative origins of peptidic transmitters is discussed and the current state of knowledge on helminth neuropeptides is reviewed. In order to place the study of helminth neuropeptides in an historical and conceptual perspective, methodological development and conceptual modifications in the disciplines of vertebrate and higher invertebrate peptide neuroendocrinology have been summarised.
Studies on the immunity of albino mice toTrichuris murisSuppression of immunity by cortisone acetate
Authors: Wakelin D.
Published: June 2009

Cortisone acetate, given to mice on two days during a primary infection with the nematodeTrichuris muris, suppressed the development of acquired immunity to the parasite. The proportion of mice in which suppression occurred was greatest when the drug was given (at 2.5 mg per mouse) on days 14 and 15 of the infection. Suppression of the response prevented the elimination of larvae, which otherwise occurs during the third week, and allowed the parasite population to mature and survive for at least a further 3 weeks. Similar treatment given during a challenge infection in resistant mice prevented the elimination of the challenge larvae for 2 or 3 days only. Mice in which cortisone treatment had prevented the elimination of a primary infection were not only found to be fully susceptible to subsequent challenge, but showed no development of immunity to the challenge infection itself. This long-lasting suppression of the immune response toT. murisis discussed and the possibility of the induction of a specific immunological unresponsiveness to the parasite is considered.
Electron-microscopical observations on the body wall of the third-stage larva ofHaemonchus placei
Authors: Smith Kenneth
Published: June 2009

The ultrastructure of the body wall of the third-stage larva ofHaemonckus placeiwas studied. The cuticle was found to consist of eight layers: a thin outer layer, a membrane-bounded layer, an electron-dense layer, a thin irregular layer, an inner cortical layer, a matrix layer, a striated layer and a fibril layer. Interposed between the inner cortex and matrix were two transverse fibres.

The region between the fibril layers and the contractile part of the muscle cells was occupied by the hypodermis, which enlarged to form the dorsal, ventral and lateral cords. Within the cords lay hypodermal cells, nerves, crystalline inclusions and an excretory canal.

The sarcoplasmic part of the muscle cells was rich in glycogen and contained numerous mitochondria. Myofibrils of two types were present in the contractile part of the cell.

I am grateful to Dr D. W. Brocklesby for his help and advice and to Mr E. Harness for the production and supply of third-stage larvae. I would also like to thank Dr D. L. Lee and Mr W. G. MacMillan for helpful discussions.