bluuebunny/crossref_metadata_2025_split huggingface dataset:
The oncomiracidia of the monocotylid monogeneans Dictyocotyle coeliaca and Calicotyle kroyeri
Authors: Kearn G. C. 
Published: June 2009

The eggs of D. coeliaca have been cultured successfully and the free-swimming larva has been studied for the first time. The eggs have an incubation period which for monogeneans is exceptionally long (4–5 months at 10 °C). Apart from maintenance at a low temperature no other special conditions such as high hydrostatic pressure or washing to remove host body fluid are necessary for development. It is not necessary for the eggs to come into contact with host body fluid before development can begin.The oncomiracidium of D. coeliaca has no eyes, a well-developed pair of anterior median gland cells and a pair of hamuli. The oncomiracidium of C. kroyeri is similar to that of D. coeliaca except for the presence of two pairs of conspicuous pigmented eyes, poorly developed anterior median gland cells, the presence of an extra pair of gland cells at the posterior end of the body and the absence of hamuli.A comparison of the larval features of D. coeliaca and C. kroyeri has confirmed that these parasites belong to quite distinct species.
Observations on the epidermis of the miracidium and on the formation of the tegument of the sporocyst of Fasciola hepatica
Authors: Southgate V. R. 
Published: June 2009

The relationship between the ciliated epidermal cells and the subepidermal layer of the miracidium of Fasciola hepatica has been described. Non-ciliated ridge-like extensions of the subepidermal layer separate the ciliated epidermal cells from each other. The sunken portions of the subepidermal layer, each containing a nucleus, lie below the outer body wall muscles of the miracidium and open into the ridge by narrow neck-like connexions. Elongate vesicles, which may be a source of stored plasma membrane similar to that which occurs in the transitional epithelium of other animals, fill most of the ridge. In addition, characteristic round electron dense granules are found in the ridge but the majority are found in the sunken portions of the subepidermal layer.The development and origins of the tegument of the sporocyst of F. hepatica have been described at the ultrastructural level. When the miracidium is in the process of penetrating the snail host, large vacuoles appear between the ciliated epidermal cells and the basal lamina which overlies the muscles of the body wall. These vacuoles have the effect of loosening the epidermal cells from the basal lamina of the body wall of the miracidium. Possible mechanisms involved in the formation of such vacuoles are suggested and discussed.During penetration of the snail the ciliated epidermal cells of the miracidium are lost; the ridge, a syncytial layer between the epidermal cells which is connected with the subepidermal layer, spreads over the basal lamina and exposed body wall muscles of the metamorphosing sporocyst to form the new outer covering of the sporocyst.Cytoplasm passes from the subtegumentary layer into the tegument during this stage of the development of the body wall of the sporocyst. Muscular contraction and microtubules may be involved in the outward movements of this cytoplasm. The nuclei of the subtegumentary layer remain below the muscles of the body wall.Twenty-four hours after penetration of the snail the outer plasma membrane of the tegument forms folds, which greatly increase the surface area.Sixty hours after penetration involutions between the folds, which may indicate pinocytosis, are present, and it is suggested that pinocytosis may play a role in food absorption.The fully formed tegument is a syncytial layer containing numerous electron dense granules, vacuoles, mitochondria and lipid droplets.The results on the formation of the tegument of the sporocyst have been discussed with reference to the controversy about the origins and terminology of the outer covering of the Platyhelminths.
A novel phosphagen phosphotransferase in the plerocercoids ofSchistocephalus solidus(Cestoda: Pseudophyllidea)
Authors: Barrett J. , Lloyd G. M. 
Published: June 2009

SUMMARYNeither phosphagens nor phosphagen phosphotransferase activity could be detected inFasciola hepatica, Hymenolepis diminuta, Moniezia expansaor in the plerocercoids ofLigula intestinalis. The plerocercoids ofSchistocephalus solidus, however, possess an active taurocyamine phosphotransferase, although it too contains no detectable phosphagens. The taurocyamine phosphotransferase ofS. solidushas an absolute requirement for a divalent metal ion and ATP could not be replaced by ITP, GTP, CTP, or UTP as the phosphate donor. The role of phosphagens in helminths is discussed.
Dipetalonema viteae: ultrastructural study on the in vitro interaction between rat macrophages and microfilariae in the presence of IgE antibody
Authors: Ouaissi M. A. , Haque A. , Capron A. 
Published: June 2009

SUMMARYThe in vitro interaction between rat peritoneal macrophages and Dipetalonema viteae microfilariae in the presence of amicrofilaraemic rat immune serum was studied by transmission electron microscopy. The probable sequence of events leading to the killing of D. viteae microfilaria by macrophages is as follows. (a) Rat peritoneal macrophages in the presence of amicrofilaraemic rat immune serum adhere to the parasite surface, (b) the macrophages extend their pseudopodia around the parasite, (c) the ‘lysosome-like’ granules discharge their contents on to the parasite surface, (d) the lytic activity of these products begins at the parasite surface and (e) subsequent breaking of the microfilarial cuticle occurs, exposing the parasite intracellular material.
Monitoring Theileria parva infection in adult Rhipicephalus appendiculatus ticks
Authors: Irvin A. D. , Boarer C. D. H. , Dobbelaere D. A. E. , Mahan S. M. , Masake R. , Ocama J. G. R. 
Published: June 2009

SUMMARYA rapid method is described for preparing and staining salivary glands of Rhipicephalus appendiculatus ticks infected with Theileria parva. The technique, involving the use of a modified methyl green pyronin stain, minimizes the risk of losing material and allows examination of stained glands within minutes of preparation. The technique was applied in a series of studies in which ticks were either infected with T. parva under different conditions, or maturation of parasites in adult ticks was stimulated by different means. When nymphal ticks were fed on the ears of cattle the subsequent infection rate of the adult ticks showed no correlation with the parasitaemia of the cattle at the time of nymphal engorgement. There was no difference in infection rates between adult ticks in which parasite maturation had been stimulated either by incubation at 37 °C or by feeding on rabbits. However, parasite maturation took about 1 day longer in incubated ticks than in rabbit-fed ticks. Female ticks were consistently more highly infected than males, both in terms of the percentage of ticks infected and the mean number of infected acini/tick. Ticks were infected with T. parva by injection of nymphs with parasitaemic bovine blood, but the resultant adult infection was lower than that in ticks which had been infected naturally by feeding on cattle.
Observations on the early relationship between Moniliformis dubius (Acanthocephala) and the haemocytes of the intermediate host, Periplaneta americana
Authors: Rotheram Susan , Crompton D. W. T. 
Published: June 2009

An electron microscope study has been made of some of the events which occur during the beginning of the relationship between Moniliformis dubius and its intermediate host, Periplaneta americana. The acanthor penetrates through the intestinal wall and is encapsulated by host haemocytes. This encapsulation is typical of the haemocytic reaction of insects to foreign bodies. A proliferation of the acanthor's surface membrane then takes place and forms a coat of microvilli. The formation of this coat by the parasite is accompanied by the dispersion or disintegration or both of the encapsulating haemocytes. The coat of microvilli constitutes a major component of the envelope surrounding early larval stages of M. dubius. There is no evidence for the presence of host connective tissue in the envelope.We are grateful to Dr A. V. Grimstone, Department of Zoology, for use of the electron microscope, and to Mr David Barnard and Miss Valerie Furber for technical assistance. We thank Dr George Salt, F.R.S. for his criticism of the manuscript.
Effects of chloroquine onPlasmodium knowlesi in vitro
Authors: Gutteridge W. E. , Trigg P. I. , Bayley P. M. 
Published: June 2009

The binding of chloroquine to DNA isolated fromP. knowlesihas been investigated. In the presence of increasing concentrations of malarial DNA, the absorption spectrum of chloroquine exhibited strong hypochromism in the range 325–350 nm, small red shifts of the absorption maxima and an isosbestic point at 300 nm. The fluorescence emission of the drug at 380 nm (excitation 330 nm) was quenched five-fold by malarial DNA. Chloroquine itself protected malarial DNA from thermal denaturation. These data are consistent with binding of the drug to malarial DNA as has been suggested from studies with DNA from bacteria and mammalian cells. The binding affinity for malarial DNA is of the same order as that for mammalian DNA.The effect of chloroquine on the metabolism ofP. knowlesiin culture was also investigated. There was a direct correlation between concentrations of drug which affect the morphology of parasites and those which affect markedly the incorporation of3H-adenosine into DNA and RNA,14C-isoleucine incorporation into protein and the formation of lactate as a result of respiration. However, all processes were inhibited to the same extent, indicating that binding to DNA is not the only action of the drug.The mode of action of chloroquine and the question of resistance to it are discussed.One of us (P. I. T.) received financial assistance from the World Health Organization. We thank Dr F. Hawking and Dr J. Williamson for many helpful discussions, Dr K. N. Brown for reading through the manuscript, and Miss Jane Dunnett, Mrs A. C. Gutteridge and Mr T. Scott-Finnigan for skilled technical assistance.
Observations on the behaviour of Dermacentor andersoni larvae infesting normal and tick resistant guinea-pigs
Authors: Allen J. R. , Kemp D. H. 
Published: June 2009

SUMMARYIn three separate experiments the behaviour of Dermacentor andersoni larvae on normal and tick-resistant guinea-pigs was studied at intervals throughout 5-day infestation periods. Fewer larvae survived on resistant hosts and their mean sizes were less than those of larvae on normal hosts, the differences becoming more obvious as time progressed. When measured at 32°C, the peristaltic rates of midgut diverticula of the larvae surviving on resistant hosts were consistently lower than those of larvae from normal hosts. Mean surface temperatures of infested ears were higher on resistant than on normal hosts. This was assumed to be a result of cutaneous hypersensitivity reactions in the resistant animals. Larvae detached, or changed attachment sites, more often on resistant than on normal hosts. This was consistently evident after 26 h post-infestation and correlated with the known timing of basophil cell infiltration and degranulation in the skin of infested, resistant guinea pigs. It appeared that most larvae, after detaching from the resistant host, died off the host. However, some died in situ while still attached. Such deaths occurred on resistant but not on normal animals between 8 and 26 h post-infestation.
A comparative study of the vitelline cell in Schistosoma mansoni, S. haematobium, S. japonicum and S. mattheei
Authors: Erasmus D. A. , Popiel I. , Shaw J. R. 
Published: June 2009

SUMMARYA comparison is given of the ultrastructure of the vitelline cell in Schistosoma mansoni, S. haematobium, S. japonicum and S. mattheei. Four stages in development of the vitelline cell have been categorized as follows: Stage 1, the undifferentiated cell; Stage 2, the developing cell showing the beginning of synthetic activity; Stage 3, the developing cell showing active protein synthesis; Stage 4, the fully mature vitelline cell. These stages in development have been defined morphologically and Stages 1, 2 and 3 are very similar in all 4 species. Lipid is present in the Stage 4 cells of all species but appears earlier at Stage 3 in S. haematobium and S. mattheei. There are several differences as to the intercellular inclusions of the Stage 4 cells, the most marked of these being the absence of calcareous corpuscles from S. japonicum as compared with the other 3 species.
Specific cross-immunity between Trichinella spiralis and Trichuris muris: immunization with heterologous infections and antigens and transfer of immunity with heterologous immune mesenteric lymph node cells
Authors: Lee T. D. G. , Grencis R. K. , Wakelin D. 
Published: June 2009

SUMMARYInfections with either 300 infective Trichinella spiralis larvae or 400 embryonated eggs of Trichuris muris were effective in eliciting accelerated expulsion of heterologous challenge infections given 20 days after the primary infection. Accelerated expulsion could also be achieved by the administration of soluble crude worm antigen given 12 days prior to heterologous challenge or by adoptive transfer of mesenteric lymph node cells taken from mice infected with the heterologous parasite. Each species is capable of eliciting an accelerated secondary expulsion response in hosts that have been actively or adoptively immunized against the other species and these results are taken to indicate that there is a specific cross-immunity between T. spiralis and T. muris due to shared antigens. It is postulated that these shared antigens are derived from stichocyte granules.
An histological and ultrastructural study of Thelohania contejeani Henneguy, 1892 (Nosematidae), Microsporidian parasite of the crayfish Austropotamobius pallipes Lereboullet
Authors: Cossins A. R. , Bowler K. 
Published: June 2009

An outbreak of the Microsporidian parasite Thelohania contejeani is reported in a population of Austropotamobius pallipes in Northumberland, U.K. Since less than 10% of all crayfish caught were infected it is concluded that T. contejeani has no serious effect on the population studied. The mode of transmission of the parasite from host to host is discussed.The host–parasite relationship and life-cycle of T. contejeani were studied using histological and electron microscope techniques. Spores were observed in some detail, and diplocarya, sporont and pansporoblast stages were identified within the general spore mass that invades host muscle tissue. Using serial sections the sporoblast ‘diplocaryon’ was shown to be a single nucleus with a deep cleft. T. contejeani was found to occur mainly in striated muscle, although it was found in cell bodies in the central nervous system.
Dipetalonema viteae infection in hamsters: enhancement and suppression of microfilaraemia
Authors: Haque A. , Chassoux D. , Ogilvie B. M. , Capron A. 
Published: June 2009

SummaryMature male Dipetalonema viteae released a substance(s) which caused eahanced microfilaraemia in infected hamsters. In hamsters implanted with female D. viteae, the microfilaraemia of a subsequent infection was suppressed. The microfilaraemia of female worms implanted in hamsters was depressed within 5 days when the animals were given a further infection with infective larvae.
Fine structural aspects of an embryo-adapted strain of Eimeria tenella in the epithelial cells of the chorio-allantoic membrane
Authors: Lücht I. G. , Millard B. J. , Scholtyseck E. G. 
Published: June 2009

SummaryThe fine structure and development of the endogenous stages of an embryo-adapted strain of Eimeria tenella in chicken embryos is described. First-generation merozoites were formed by endodyogeny in uninucleate developmental stages as well as schizogony and the endoplasmic reticulum of merozoites of the second-generation schizonts appeared as a circular structure, often enclosing other organelles. In contrast to the parent strain, development of the second-generation schizonts was restricted to cells of epithelial origin. These observations confirm that the complete endogenous cycle of the embryo-adapted strain of E. tenella is restricted to epithelial cells of the chorio-allantoic membrane (CAM) and that no major ultrastructural changes have occurred as a result of repeated embryo passage.
Activation of succinate dehydrogenase from adultFasciola hepatica(Trematoda)
Authors: Barrett J. 
Published: June 2009

SummaryThe succinate dehydrogenase of adultFasciola hepaticawas found to exist in active and inactive forms. The enzyme was inactivated by 1 μM oxaloacetate and activated by incubation with compounds which bind to the active site (succinate, fumarate, malonate) or by incubation with anions and certain nucleotides. The activation of the enzyme by succinate followed first-order kinetics. The extent of activation ofF. hepaticasuccinate dehydrogenase depended on the nature and concentration of the activator and on the pH. The rate of activation of the enzyme depended on the temperature. In contrast, the fumarate reductase activity ofF. hepaticawas not activated by incubation with substrate or anions and was not inhibited by oxaloacetate (100 μM). The significance of these results in the regulation of the tricarboxylic acid cycle in parasitic helminths is discussed.
Strongyloides ratti: the effect of betamethasone on the course of infection in rats
Authors: Moqbel R. , Denham D. A. 
Published: June 2009

SummaryRats were treated with betamethasone at different stages of infection withStrongyloides ratti. Treatment caused a diminution in the number of adult worms recovered but this residual population was not expelled as were worms from untreated rats. If treatment was started after expulsion had already begun adult worm numbers increased – suggesting that auto-infection occurred. Treatment throughout a primary infection prevented the development of an immune response which expelled, or killed, a challenge infection. Treatment, just before and just after challenge, prevented the expulsion of the challenge infection. Worm expulsion up to day 35 was prevented by treating rats with betamethasone 4, 6, 8 and 10 days after infection.
The effect of vitamins A, E and K on experimentally induced histomoniasis in turkeys
Authors: Schildknecht E. G. , Squibb R. L. 
Published: June 2009

SUMMARYVitamins A, E and K were incorporated into turkey starter rations at normal (1×), 5× and 50× the National Research Council recommended vitamin levels and evaluated for their effect on histomoniasis in turkeys. Infected as well as comparable uninfected poults were included in all trials. Each vitamin was also evaluated at normal and 50× the NRC level in combination with ipronidazole, a low-level antihistomonal agent. In addition to performance parameters, glutamate oxaloacetate transaminase (GOT) and lactate dehydrogenase (LDH) plasma enzyme levels were used to evaluate the vitamin effect. None of the vitamins tested alone were found to be effective in terms of reducing mortality and morbidity following a severeHistomonas meleagridischallenge, regardless of the vitamin dose. A significant improvement in performance was demonstrated with the vitamin E (50×)–ipronidazole combination and a numerical improvement with the vitamin A (50×)–ipronidazole combination over ipronidazole alone or the poults fed NRC recommended vitamin levels. The GOT and LDH plasma enzyme levels correlated well with the progressive pathological changes associated with the disease. At 11 days post-infection both enzymes were consistently and significantly elevated above those of the uninfected controls, irrespective of the vitamin levels provided. The presence of low level ipronidazole in most instances delayed the onset of clinical symptoms and was associated with a delay in enzyme elevation, indicating the excellent correlation and sensitivity of the enzyme method in assessing liver damage.
Effect of dimetridazole on transmission of Histomonas meleagridis by Heterakis gallinarum
Authors: Chute M. B. , Chute Anne M. , Wilkins G. C. 
Published: June 2009

SummaryThe administration of an antihistomonal drug, dimetridazole, at a dose of 0·08% in feed, controlled experimental infections with Histomonas meleagridis in chickens. The treated birds developed no lesions and the duration of infection with H. meleagridis was reduced. This drug regimen, however, did not always prevent incorporation of H. meleagridis into eggs of Heterakis gallinarum; heterakid eggs pooled from medicated chickens in which H. meleagridis had never been detected transmitted the protozoan to 1 of 10 turkeys fed the eggs. Thus, therapeutic treatment of chickens with dimetridazole may reduce, but not eliminate, transmission of H. meleagridis by eggs of H. gallinarum from medicated birds.
Mannosyl transferase activity in homogenates of adult Schistosoma mansoni
Authors: Rumjanek F. D. , Smithers S. R. 
Published: June 2009

SummaryHomogenates of adult Schistosoma mansoni contain enzymes which are capable of transferring [14C]mannose from GDP[U-14C]mannose to a lipid acceptor which migrates as a single peak on a silica gel thin-layer plate. This lipid may belong to the class of polyprenol monophosphates which are intermediate elements in the glycosylation of nascent proteins. The schistosome mannosyl transferase activity is associated with membranous particles and is dependent on the presence of Mn2+. However, other divalent metals such as Mg2+ or Ca2+ can, in decreasing order of efficiency, replace Mn2+. When UDP[U-14C]glucose was incubated with the homogenates in the same conditions, relatively little label was transferred to the lipid acceptor. Live worms incubated in a medium containing GDP[U-14C]mannose seem to incorporate the label preferentially on the tegument and on adjacent subtegumental structures. By adding foetal calf serum to the medium, incorporation of the label can be stimulated.
Factors affecting the acquisition of resistance againstSchistosoma mansoniin the mouse. IV. The inability of T-cell-deprived mice to resist re-infection, and otherin vivostudies on the mechanisms of resistance
Authors: Doenhoff M. , Long E. 
Published: June 2009

SUMMARYCBA mice deprived of their T-cells by means of thymectomy and administration of rabbit anti-mouse thymocyte serum before a primary infection ofSchistosoma mansoni, failed to resist re-infection to the same extent as immunologically intact controls. However, little difference was made to the degree of resistance to re-infection acquired by thymectomizedS. mansoni-infected mice when the anti-thymocyte serum was administered after the primary infection and just before the challenge. Hydrocortisone acetate, when administered to primarily infected mice just before reinfection appeared to reduce the degree of acquired resistance, but the drug also had a schistosomicidal effect on the challenge-derived organisms. An attempt to specifically suppress the acquisition of resistance againstS. mansoniby administering serum from homologously infected, resistant donors before and during the course of a primary infection failed, and partial depletion of complement activity with cobra venom factor that was administered just before challenge also failed to affect resistance. Serum obtained from mice with chronicS. mansoniinfections and injected intradermally at the site of subsequent administration of a homologous percutaneous challenge infection failed to markedly inhibit maturation of the challenge in the recipient. Recipients of 3 ml of serum from heavily infected donors were also not significantly more resistant to challenge than untreated controls. However, isolated skin from heavily infected mice allowed fewer cercariae to penetrate and emerge transformed as schistosomula than did isolated skin from uninfected controls.