bluuebunny/crossref_metadata_2025_split huggingface dataset:
Schistosoma mansoni: ability of Con A to protectin vitromechanically transformed schistosomula against the lethal effect of immune serum plus complement
Authors: van Pijkeren Thea A. , Tavares C. A. P. , Gazzinelli G. 
Published: June 2009

SUMMARYConcanavalin A added to a defined culture medium renders schistosomula more resistant to the lethal effect of antibody plus complement. The Con A dose-dependent acquisition of protection reached a plateau at a concentration of 4 μg Con A/ml. α-Methylmannoside was not able to reverse the Con A-induced protection but excess methylmannoside, added to the incubation medium together with Con A partially prevented the effect of the lectin. Binding of anti-parasite antibody to the schistosomula surface did not change after pre-incubation with Con A. In the presence of puromycin (100 μg/ml) Con A is still able to confer protection. Incorporation of labelled amino acid into the tegumental proteins was not affected by Con A. Furthermore, a progressive reduction of protection was observed as the time of culture preceding Con A addition increased.
Possible immunological damage to the tegument ofHymenolepis diminutain mice and rats
Authors: Befus A. D. , Threadgold L. T. 
Published: June 2009

Opaque or darkened areas (DA) of variable size and position occur onHymenolepis diminutain mice and rats. In mice DA normally first appear in the neck region of the worm but subsequently they appear elsewhere and increase in number until destrobilation or worm expulsion. The posterior of destrobilated worms is often darkened. In the more immunogenic infections with six cysticercoids there are more DA per worm than in infections with one cysticercoid. DA are areas of the tegument with a homogeneous increase in electron density; abnormal mitochondria; reduced granular endoplasmic reticulum, Golgi complexes and discoidal secretory bodies; and accumulation of lipid droplets. DA disappear from worms maintained for up to 4 h in Hanks' balanced salt solution and can be induced by mechanical damage to the worms.As the numbers of DA increase with the duration and intensity of infection and have similarities with types of cell injury, they are probably sites of worm pathology induced by host immunity.
Cryptocotyle lingua (Creplin) (Digenea: Heterophyidae): observations on the morphology of the redia, with special reference to the birth papilla and release of cercariae
Authors: Irwin S. W. B. , Threadgold L. T. , Howard Nicola M. 
Published: June 2009

SummaryRediae of Cryptocotyle lingua were studied using transmission and stereoscan electron microscopy. The mouth is surrounded by numerous ciliated sensory structures. Posteriorally, the body wall is concentrically folded and its surface area is greatly increased by the closely ridged configuration of the outer membrane of the tegument. Attached to the surface, especially at the anterior end, are numerous, small spherical vesicles. At the posterior end there is a retractable papilliform process. The appearance of the surface of the birth papilla is variable. The birth pore is lined by an epithelium which is specialized to withstand extreme distortion. A single cilium is frequently visible in the birth pore lumen. The release of each cercaria is preceded by the emission of a tiny drop of fluid from the birth pore. It is suggested that this fluid acts as a lubricant to the passage of the cercaria through the pore.
Active entry of bloodstream forms ofTrypanosoma cruziinto macrophages
Authors: Kipnis T. L. , Calich V. L. G. , da Silva W. Dias 
Published: June 2009

SUMMARYThe uptake of bloodstream forms ofTrypanosoma cruzi, Y and CL stocks, by mouse peritoneal macrophages and their intracellular differentiation and multiplication has been comparedin vitro. After 48 h the number of macrophages showing intracellular amastigote forms was higher when the Y stock was used. The number of parasitized cells increased with the time of contact between parasites and macrophages. Prior treatment of the parasites with anti-T. cruziantibodies and/or complement increased the number of infected macrophages, but did not interfere with their subsequent differentiation within the macrophages. The number of parasitized cells was greater when macrophages were obtained from mice previously treated with lipopolysaccharide, peptone or thioglycollate. Uptake was not appreciably affected when macrophages were pre-treated with trypsin or anti-macrophage serum, or when the parasites and macrophages were incubated in the presence of cytochalasin B. In the same experimental conditions, epimastigotes ofT. cruziwere not able to differentiate into amastigotes. Their uptake was potentiated by previous treatment with specific antibodies and/or complement and was blocked by cytochalasin B. These results confirm that epimastigotes derived fromT. cruzicultures are phagocytosed and suggest that bloodstream forms penetrate actively into macrophages.
Effects of saturated sodium chloride solution on coccidial oocysts
Authors: Ryley Nicholas G. , Ryley John F. 
Published: June 2009

SummaryUsing the ability to sporulate as a measure of viability, the effects of exposure of unsporulated oocysts of 10 species of coccidia of chickens, rabbits and cattle to saturated NaCl solution has been studied. Although appreciable deformation and collapse of the oocyst occurred after 1–2 days contact, the effect was reversible after washing free from salt and incubating. Some reduction in ability to sporulate following several days contact with saturated salt was noted in most species, although no effect was seen with Eimeria stiedai following 7 days exposure, Eimeria tenella was one of the more sensitive species studied. Culture titration experiments in chickens with E. tenella indicated that oocysts which had sporulated following prolonged exposure to salt were in no way inferior in virulence or ability to retain virulence on prolonged storage to oocysts prepared with minimal contact with salt. No evidence was obtained to contra-indicate the use of salt-flotation methods for the separation of oocysts from faeces.
Oviposition, hatching and the oncomiracidium of Eupolystoma anterorchis (Monogenoidea)
Authors: Tinsley R. C. 
Published: June 2009

SummaryEupolystoma anterorchis Tinsley, 1978, infects the urinary bladder of Bufo pardalis at the Cape, South Africa. Reproduction occurs throughout the year but the eggs are not deposited continuously: up to 300 are retained in the long uterus of the parasite and may develop to the point of hatching. The eggs are deposited intermittently en masse. The stimulus for deposition appeared to be osmotic, since worms transferred from the host's bladder into freshwater released their stored eggs. However, in simple experiments where hosts were transferred from dry land to water such egg deposition did not follow and the stimulus requires further investigation. Once discharged from the uterus the oncomiracidia hatch rapidly both in water and in host urine. Those eggs immediately expelled from the bladder at urination release larvae which can infect the same or other host individuals via the cloaca. But when eggs are deposited in the bladder between successive host urinations larvae can emerge and attach themselves directly to the bladder wall. These larvae develop to maturity alongside their parents, and this internal re-infection can give rise to massive levels of infestation. The distributions of the tegumental ciliated cells and sensillae of the oncomiracidium have been determined with silver impregnation. There are 55 ciliated cells whose pattern corresponds with that of Polystoma species except for the orientation of three dorsal cephalic cells. The distributions of their tegumental sensillae show greater divergence and the Eupolystoma larva lacks the hamulus primordia typical of Polystoma.
A scanning electron microscope study of the effect of an ovicidal fungus on the eggs of Ascaris lumbricoides
Authors: Lýsek H. 
Published: June 2009

SummaryAspects of the ovicidal activity of the fungus Verticillium chlamydosporium Goddard on the eggs of Ascaris lumbricoides were observed in the laboratory using a scanning electron microscope. The hyphae of the fungus form structures which are considered to be penetration organs. The hyphae also form a network over the surface of the eggs. After penetration of the eggs, the hypha or hyphae ramify and the embryos are destroyed.
Schellackia landauaesp.nov. (Eimeriorina: Lankesterellidae) in the Brazilian lizardPolychrus marmoratus(Iguanidae): experimental transmission byCulex pipiens fatigans
Authors: Lainson R. , Shaw J. J. , Ward R. D. 
Published: June 2009

SummaryA new haemogregarine,Schellackia landauaesp.nov., is described in the Brazilian lizardPolychrus marmoratus(Linn) from Pará State, north Brazil. Sporozoites are found principally in the red blood cells (84%) in the peripheral blood but also occur in lymphocytes and monocytes. Experimental transmission to three uninfectedP. marmoratuswas achieved after feeding them with laboratory-bredCulex pipiens fatiganswhich had engorged on an infected lizard 14 days previously. The cycle of development in the small intestine ofP. marmoratustakes approximately 30 days: schizogony, gametogony and fertilization of the macrogametocytes is in the epithelial cells of the gut, with zygotes penetrating the lamina propria, where the mature oocysts develop. Living oocysts average 14·3 × 13·3 μm, and are approximately 10·0 μm as seen in histological sections. During the period of intestinal development, the parasite also undergoes asexual multiplication within cells of the spleen and liver by a process which appears to be endodyogeny. The exact time required before the first invasion of the peripheral blood by the sporozoites remains to be ascertained, but is some time within 30–45 days after the lizard ingests the infected mosquitoes. Morphology of the sporozoite in the vertebrate host is variable and depends on the host cell occupied; there may be 1 or 2 refractile bodies. Reduction or fusion of these to a single refractile body in those sporozoites within the gut cells of the infected mosquito suggests that the bodies may represent some form of energy source that is used up during this latent phase in the insect vector. Accumulation of sporozoites takes place in the reticulo-endothelial cells of the viscera, in particular the pigmentladen cells of the liver and lung. Attempts to infect other species of lizards,Tropidurus torquatus(Iguanidae) andAmeiva ameiva(Teiidae) failed.
Accelerated expulsion of adult Trichinella spiralis in mice given lymphoid cells and serum from infected donors
Authors: Wakelin D. , Lloyd M. 
Published: June 2009

SummaryImmunity to the adult stage of Trichinella spiralis, assessed by an acceleration of worm expulsion, was transferred to recipient mice with mesenteric lymph node cells (MLNC) or serum taken from infected donors. Immunity was transferred most effectively by MLNC taken from donors infected for 8 days, i.e. donors actively responding to infection. Transfer of both MLNC and serum brought about a marked acceleration of worm expulsion in all cases, even where MLNC or serum given separately failed to transfer a significant degree of immunity.
Diplostomum spathaceum(Rud. 1819): effects of physical factors on the infection of rainbow trout (Salmo gairdneri) by cercariae
Authors: Stables J. N. , Chappell L. H. 
Published: June 2009

SUMMARYThe relationship between infection rates of rainbow trout (Salmo gairdneri) byDiplostomum spathaceumand cercarial concentration, water flow rate and temperature were investigated by means of controlled infections within a flume. A linear relationship was obtained between cercarial concentration and mean abundance of metacercariae/fish. A biphasic relationship occurred between flow rate and abundance of metacercariae. Within the confines of the flume, it was possible to control the infection rate of trout withD. spathaceumcercariae by manipulating flow rate, suggesting that it may be a possible method of controlling diplostomiasis on fish farms. No infection occurred in fish infected and maintained below 10°C and the optimum infection temperature was approximately 17·5°C. Infections became established in fish infected at 7·5 and 5°C but maintained at 15°C prior to examination. Trout were infected at 7·5°C for 10–50 min and all attached cercariae were washed off and removed from the flume. Following infection, fish were either maintained at 7·5°C or 15°C prior to examination. Using this method, it was possible to ascertain that it was migration and not penetration which was inhibited at water temperatures below 10°C.
A comparison of the surface and secertions ofTrichinella pseudospiralisandT. spiralis
Authors: Almond N. M. , McLaren Diane J. , Parkhouse R. M. E. 
Published: June 2009

SUMMARYIntact, viable adults, infective and newborn larvae ofTrichinella pseudospiraliswere surface labelled with125I by the chloramine T method and labelled proteins were compared with those obtained from equivalent stages ofT. spiralis. Electron-microscope autoradiography determined that labelled proteins were restricted to the cuticle for all stages of both isolates. Comparative polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate (SDS–PAGE), using thin gradient gel slabs, of proteins obtained from each stage, demonstrated that the profile of surface-labelled proteins ofT. pseudospiraliswere restricted in number, stage specific, and similar to equivalent proteins ofT. spiralisboth in size and in their organization into aggregates. The stage-specific profiles of surface-labelled proteins derived from newborn larvae were indistinguishable, but differences were noted between adults and infective larvae of the two isolates. These differences in protein structure were confirmed by two dimensional mapping of tryptic peptides. Stage-specific profiles were also obtained when [35S]methionine biosynthetically labelled secretions of the 3 stages ofT. pseudospiraliswere compared by SDS–PAGE. Comparison of the profiles obtained with secretions for respective stages ofT. spiralisagain failed to distinguish newborn larvae, but adults and infective larvae ofT. spiralisandT. pseudospiralisdisplayed a mixture of common and species-specific proteins. These findings are discussed in relation to the different pathology associated with infection with two isolates.
Acetylcholinesterase activity in Nippostrongylus brasiliensis during the course of a primary infection in normal and in protein-deficient rats
Authors: Martin Jean 
Published: June 2009

SUMMARYAcetylcholinesterase (AChE) activity was measured in Nippostrongylus brasiliensis recovered during the course of a primary infection in normal and in protein-deficient rats. In well-nourished rats the amount of AChE present in N. brasiliensis increased as the infection progressed, concomitant with the development of the humoral response. In malnourished rats, there was a similar and parallel increase in the amount of AChE synthesized by worms between days 7 and 13 of the infection but as the infection progressed enzyme production decreased so that, by day 26 of the infection, the nematodes contained approximately the same amount of AChE as 8-day-old worms. The possible reasons for this change in enzyme production are discussed.
Evasion of the oxidative microbicidal activity of human monocytes by trypomastigotes ofTrypanosoma dionisii
Authors: Thorne Kareen J. I. , Glauert Audrey M. , Svvennsen Rosamund J. , Thomas H. , Morris Jane , Franks D. 
Published: June 2009

SUMMARYTrypomastigotes ofTrypanosoma dionisii, a stercorarian trypanosome from bats, are effectively killed by neutrophils from human peripheral blood but are less sensitive to the cytotoxic action of human monocytes. The mechanism of killing appears to involve peroxidase and hydrogen peroxide. Trypomastigotes are as effective as epimastigotes in inducing the formation of hydrogen peroxide by effector cells. They are, however, less sensitive than epimastigotes to the cytotoxic effect of peroxidase and hydrogen peroxide. They are therefore susceptible to the high concentrations of peroxidase found in the phagosome of the neutrophil, but resist the lower levels encountered in monocytes.
Antigenic analysis of sequential erythrocytic stages ofPlasmodium knowlesi
Authors: Deans J. A. , Dennis E. D. , Cohen S. 
Published: June 2009

SummaryThe antigenic composition of sequential erythrocytic stages ofPlasmodium knowlesihas been compared by crossed immuno-electrophoresis using a pool of immune rhesus monkey antiserum. Eleven major parasite antigens have been identified; 9 are stage-independent, and 2 stage-dependent. Differences in the relative amount of the stage-independent antigens have been demonstrated and quantified. The distribution of antigens between parasites and schizont and infected red cell membranes has been examined. Only 6 of the 11 parasite antigens were exhibited by a schizont membrane preparation, all these antigens were also expressed by the intracellular parasite. Antigens exclusive to the schizont membrane were not demonstrated.
Nematodirus battus: structure of the body wall of the adult
Authors: Martin Jean , Lee D. L. 
Published: June 2009

SUMMARYMales ofNematodirus battushave a body wall composed of a longitudinally ridged cuticle made up of 8 layers, a hypodermis and a layer of longitudinal muscle cells which are divided into 4 sectors by the hypodermal cords. There is a characteristic cephalic inflation of the cuticle in both sexes. The structure of the body wall in the anterior half of the female is similar to that of the male. In the posterior half of the female the cuticle is not ridged and has 7 layers; the longitudinal muscles are reduced in number and the lateral hypodermal cords increasingly extend dorsally and ventrally along the length of the posterior part of the nematode and come to occupy most of the lateral sectors of the body. The possible significance of these modifications in the structure of the female nematode are discussed.
The cell biology of sexual development in Plasmodium
Authors: Sinden R. E. 
Published: June 2009

SUMMARYThis review examines the sexual development ofPlasmodiumspp. particularly relating the ultrastructural organization of their cells to the limited, though rapidly expanding, body of metabolic and biochemical studies. Thus it is hoped the article may provide a useful background of information for those undertaking studies on the sexual parasites with the objective of developing methods for the immunological and chemo-therapeutic control of malaria transmission. These objectives, however, should not dominate our clear recognition that the three phases of sexual development, gametocytogenesis, gametogenesis and fertilization contain within them examples of control and assembly of organelles without peer amongst eukaryotic cells.
Fine structural observations on oocyte development in monogeneans
Authors: Halton D. W. , Stranock S. D. , Hardcastle Anne 
Published: June 2009

SummaryThe ultrastructural changes accompanying oocyte differentiation in the ovaries of the monogeneans, Diclidophora merlangi, Diplozoon paradoxum and Calicotyle kröyeri have been described. In each case, oogenesis in the ovary proceeds as far as meiotic prophase in the primary oocyte. A three-stage sequence of development based on oocyte morphology is proposed: (1) Oogonia and early, immature primary oocytes are typically undifferentiated, with chromatin-laden nuclei occupying most of the cell volume. The cytoplasm contains small clumps of mitochrondria and unattached ribosomal aggregates. There is evidence of mitosis and, in later stages, meiotic prophase is indicated by the appearance of nuclear synaptonemal complexes. (2) Maturing primary oocytes are characterized by increased nucleolar volume associated with the production of RNA for export to the cytoplasm. An organized GER and Golgi apparatus are established and involved in the synthesis and packaging of membrane-limited cortical granules. Annulate lamellae and nucleolus-like bodies appear in the cytoplasm and, with development, the cells increase in size and, peripherally, become interdigitated. (3) Mature primary oocytes represent a resting phase when cellular activity is minimal. Golgi disappear and the ER fragments or becomes reduced in dimensions. Mitochondria and free ribo-somes are numerous and cortical granules move to the cell periphery. The cells separate and, when mature, are released from the ovary. There are minor species differences in oocyte ultrastructure and development.
Boophilus microplus: the effect of host resistance on larval attachments and growth
Authors: Kemp D. H. , Koudstaal D. , Roberts J. A. , Kerr J.D. 
Published: June 2009

SummaryGrowth and behaviour ofBoophilus micropluslarvae on British breed cattle, with different resistance levels to the tick, were studied to elucidate the nature of resistance. On highly resistant animals, larval growth rate was slower for the first 3 days, but by day 4 they had attained the normal weight and the majority were subsequently able to moult.Using phosphorus-32 labelled larvae, it was found that attachment times were shorter and more time was spent wandering on highly resistant animals during the first 16 h. On the second day, attachments had stabilized, but more detachments were still made from highly resistant animals. This was considered to impose an additional stress as the cattle skin environment can rapidly desiccate larvae. However, the larvae were able to compensate by uptake of fluid from the host.Loss by repulsion of live larvae from the host or drowning in serous exudate were also not considered of major importance. The nature of rejection is discussed in a further paper.The distribution of larvae after 24 h suggests that their early behaviour largely determines the areas favoured by adults. Movement to, and accumulation in, favoured areas is discussed.
The mechanism of pyrimethamine resistance inPlasmodium falciparum
Authors: Dieckmann A. , Jung A. 
Published: June 2009

SUMMARYThe uptake of radioactive pyrimethamine by a sensitive and a resistant strain ofPlasmodium falciparum, the metabolic fate of pyrimethamine inside these parasites and the kinetic properties of dihydrofolate reductase (DHFR) from both strains have been studied. Uptake of the drug was identical in both strains and no metabolite of pyrimethamine was found in either strain. DHFR from the resistant strain was 300 times less sensitive to inhibition by pyrimethamine than the enzyme from the sensitive strain, while the Michaelis constant for dihydrofolate remained unchanged and inhibition was competitive in both cases. Altered properties of plasmodial DHFR are apparently the only mechanism responsible for pyrimethamine resistance in the strain ofPlasmodium falciparumstudied.
Seasonal and age distributions ofBabesia, Hepatozoon, TrypanosomaandGrahamellaspecies inClethrionomys glareolusandApodemus sylvaticuspopulations
Authors: Turner C. M. R. 
Published: June 2009

SUMMARYFour common blood parasites belonging to the generaBabesia, Hepatozoon, TrypanosomaandGrahamellawere detected in sympatric populations ofClethrionomys glareolusandApodemus sylvaticus. Seasonal changes in the abundance of hosts and parasites were monitored in a longitudinal field survey for 18 months. All parasites in both hosts showed similar seasonal patterns with most transmission occurring in summer and autumn and ceasing in winter. Amongst aged subsets of each host population,HepatozoonandGrahamellaspp. were primarily parasites of young animals whereasBabesiaandTrypanosomaspp. generally infected older hosts. Data from the aged subsets were also used to estimate values for the basic reproductive rate,R0, for each parasite. InC. glareolus,R0= 2·0 forB. microti, 2·6 forH. erhardovae, 1·7 forT. evotomysand 2·8 forGrahamellasp. InA. sylvaticusR0= 2·2 forGrahamellasp. These estimates are probably representative only for summer and autumn of each year.