bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation of blood and intracellular forms ofTrypanosoma cruzifrom rats and other rodents and preliminary studies of their metabolism
Authors: Gutteridge W. E. , Cover B. , Gaborak Maria 
Published: June 2009

SummaryIsolation of blood and intracellular forms ofTrypanosoma cruziwas made mainly from rats (90–110 g) which had received 580 rad of whole-body γ-irradiation not more than 24 h before subcutaneous inoculation with 107trypomastigotes of the Sonya strain ofT. cruzi. Unirradiated chinchillas (250–350 g) were, however, used for some experiments. Blood forms were isolated using a technique involving differential centrifugation to remove most of the erythrocytes and DEAE–cellulose chromatography to remove the remaining blood cells. Overall recoveries were usually in the range 30–70%. Parasites were mainly (approximately 98%) broad forms and were motile, metabolically active (as judged by respiratory and radio-tracer incorporation studies) and had lost none of their infectivity for mice. Intracellular forms were isolated from hind-limb muscle tissue. This was disrupted in an MSE tissue homogenizer and the homogenate incubated with DNase, collagenase and trypsin. Parasites, contaminated only by a few blood cells, were then obtained by differential centrifugation. For purer preparations, a terminal sucrose gradient step was used. Recoveries ranged between 40 and 70%. About 1–3% of the parasites isolated were epimastigotes and trypomastigotes; the remainder are probably best collectively termed ‘amastigotes’, though they were pointed and most had a short, free flagellum. They were undamaged as judged by light and electron microscopy and metabolically active as judged by respiratory and radio-tracer incorporation studies. However, the infectivity for mice of both these purified preparations and the initial cell homogenates could be accounted for by the epimastigotes and trypomastigotes present in them. Preliminary biochemical studies with isolated parasites have shown that blood, intracellular and culture forms ofT. cruzihave a respiratory system which is in part sensitive to CN- and that all forms synthesize nucleic acids and proteins when incubatedin vitro. There appears, however, to be a lack of DNA synthesis in blood stages, and thus it is not surprising that these forms do not divide.
Studies on the immunity of sheep toOesophagostomum columbianum: effects of low-protein diet on resistance to infection and cellular reactions in the gut
Authors: Dobson Colin , Bawden Richard J. 
Published: June 2009

AdultOesophagostomum columbianumpopulations were larger in sheep fed low-protein diets than in adequately fed animals. Diet did not influence the numbers of larva which became established in sheep. Sheep fed high-protein diets eliminated more worms and were more immunologically competent than poorly fed animals. More encapsulated larvae, showing arrested development, were found in adequately fed sheep than in those fed low-protein diets. AdultO. columbianumproduced eggs at an earlier time after infection in poorly fed sheep than worms in well fed sheep. More eggs/female worm were produced in sheep on a low-protein diet compared with the number of eggs produced in well fed hosts over the last week of the infection. The effects of immunity on the behaviour of the worm in both host diet groups is discussed.There was a greater cellular proliferation in the intestines of infected adequately fed sheep than in infected animals on low-protein diets. These changes were most pronounced in the large intestine where the adult parasites were found. The macrophage-lymphocyte series of cells underwent hyperplasia in well fed animals but these changes were reduced, particularly among the plasma cells, in sheep fed low-protein diets. Increased mucin and mast cell counts were observed in sheep on high-protein, but not in hosts on low-protein diets: the intestinal populations of eosinophil and globule leucocytes were also reduced in poorly fed sheep.The relationship of these various cellular reactions and their effect on the protective immunity of sheep toO. columbianumis discussed. It was concluded that the increased susceptibility of protein deprived sheep toO. columbianuminfections was associated with malfunctions of the innate immunity of the gut, involving decreased peristalsis and failure of the mucin cell response, and with reduction of the adaptive immune response which was reflected by impoverished lymphocyte and plasma cell reactions, and possibly with poor cooperation between sensitized lymphocytes, antibodies and the mast cell-granulocyte effector mechanisms in protective immunity.
A comparative study of the glandular and excretory systems of the oncomiracidia of the monogenean skin parasitesEntobdella hippoglossi, E. diademaandE. soleae
Authors: Kearn Graham C. 
Published: June 2009

A comparison of the oncomiracidia of the monogenean skin parasitesEntobdella hippoglossifrom the halibut (Hippoglossus hippoglossus), E. diademafrom the sting ray (Dasyatis pastinaca) andE. soleaefrom the skin of the common sole (Solea solea) has revealed the presence of ‘body gland cells’, all of which have openings on the ventral or lateral surfaces of the larvae. In all three species there are two pairs of glands lying in the posterior region of the body proper with long ducts extending into the haptor and opening on its ventral surface. In addition to these two pairs of glands there are seven other pairs of body glands inE. hippoglossi, six pairs inE. diademaand two pairs inE. soleae.InE. soleaeall the ‘body gland cells’ are poorly developed in the oncomiracidium and are more conspicuous in post-oncomiracidia. The fate of the ‘body gland cells’ during post-oncomiracidial development has been studied inE. soleae, and their possible functions are discussed. The glands in the head region (anterior median, posterior median and lateral head glands) are similar in all three species. Gland cells associated with the alimentary system are less easy to observe but differences between the three species appear to be small.In the oncomiracidia of all three species the number of flame cells and their distribution are the same, but the oncomiracidia ofE. hippoglossiandE. diademahave loops in the excretory ducts anterior to the bladder and the bladders ofE. diademacontain refringent bodies.The oncomiracidial eyes ofE. hippoglossiandE. soleaehave lenses but the lenses are greatly reduced in the oncomiracidia ofE. diadema.In the three larvae there are small but characteristic differences in the shapes of the accessory sclerites.The oncomiracidium ofE. hippoglossihas not previously been described.
The ultrastructure of the tegument of the daughter sporocyst of Microphallus similis (Jäg., 1900) (Digenea: Microphallidae)
Authors: Popiel Irene , James B. L. 
Published: June 2009

SummaryIn the fully formed daughter sporocyst of Microphallus similis (Jäg.) the tegument is divided into a wide, outer cellular epithelium and a narrow, inner electron-dense anucleated microvillous syncytium. The narrow subtegument consists of circular and longitudinal muscle, nervous, synthesizing and germinal cells. It is suggested that during development of the tegument, an undifferentiated nucleated syncytium becomes divided by the formation of membranes between the nuclei and between the narrow, inner electron-dense microvillous and the outer cellular regions. The outer nucleated region of the tegument is homologous to the nucleated investing syncytium which surrounds redial and cercarial embryos and which is shed later in development. The retention of the nucleated region in some daughter sporocysts is, therefore, an example of paedogenesis.
Euzetrema knoepffleri: evidence for a synchronous cycle of the gastrodermal activity and an ‘apocrine–like’ release of the residues of digestion
Authors: Fournier Annie 
Published: June 2009

SummaryEuzetrema knoepffleri (Monogenea, Monopisthocotylea), an endoparasite of Euproctus montanus (Amphibia, Urodela), has a partially haematophagous diet, resembling that of the Polyopisthocotylea. In spite of this, the ultrastructural characteristics of the gastrodermis are typical of Monopisthocotylea. As in the Monogenea already described, digestion is intracellular with a lysosomal process, but two original features are evident. First, there is a cyclic activity of all the digestive cells during digestion with a synchronization of events, which enables two characteristic stages to be distinguished. Secondly, the elimination of the waste is similar to an ‘apocrine’ process, in which the apical portion of cytoplasm filled with residual bodies or the entire cell is released into the caecal lumen.
Humoral encapsulation in Diptera (Insecta): comparative studiesin vitro
Authors: Vey A. , Götz P. 
Published: June 2009

The humoral encapsulation reaction of larvae ofChironomushas been reproduced and studiedin vitro. This reaction is activated by entomogenous fungi and certain foreign bodies as well as by nematodes. The different stages of encapsulation and the duration of the process have been determined. In the larvae of a given species of Chironomidae encapsulation does not vary with age or sex. In contrast, the duration of the process differs according to the species of Chironomidae and is modified by temperature or by parasitism of the host by Mermithidae.The capsules contain melanin. Their formation is prevented by glutathion, an inhibitor of phenoloxidase.The humoral type of encapsulation also occursin vitroin the haemolymph of larvae of the nematocera families, Culicidae and Chaoboridae. However, the reaction of these insects differs in the amount, distribution and pigmentation of the capsular material.The results demonstrate similarities between humoral and cellular encapsulation.
Studies on the mode of action of beclotiamine on Eimeria tenella
Authors: Matsuzawa Toshiaki 
Published: June 2009

SummaryThe thiamine antagonist beclotiamine showed anticoccidial activity against Eimeria tenella, although metabolites and related substances were inactive. Oocyst production in experiments employing unilateral caecal ligation suggested that the drug reached parasitized cells by downward movement through the intestinal lumen, rather than by absorption and systemic transport. In chickens given 100 p.p.m. beclotiamine in the feed over a period of 7 days, duodenal drug concentrations of approximately 5·8 p.p.m. were achieved and maintained, while concentrations in the caeca were lower, but gradually increased to 1·2 p.p.m. Caecal levels were slow to fall following drug withdrawal, whereas duodenal levels showed an immediate decrease. [3H]thiamine absorption from the caeca of normal chicks or of chicks infected with E. tenella was inhibited by oral administration of beclotiamine. Pyrithiamine showed slight anticoccidial activity at 30 p.p.m. as did 2,4-dinitrophenol (2,4-DNP) at 100 p.p.m. A combination of 40 p.p.m. beclotiamine and 200 p.p.m. 2,4-DNP was quite effective although weight gains were not as good as with 120 p.p.m. beclotiamine alone.
Neuromuscular physiology of Grillotia erinaceus metacestodes (Cestoda: Trypanorhyncha) in vitro
Authors: Ward S. M. , Allen J. M. , McKerr G. 
Published: June 2009

SUMMARYIsometric tension recordings and the single sucrose-gap technique were used to record mechanical and electrical activity from Grillotia erinaceus metacestodes in vitro. Both complete preparations and those cut longitudinally (to allow access of the bathing medium to the region of the somatic muscle) showed spontaneous contractions of frequency ≃ 1/min in Hanks’ Balanced Salt Solution (HBSS) at 13 °C. Changing the pH, temperature or osmolarity of the HBSS did not improve the activity but rather abolished it at extremes of these variables, so confirming the adequacy of the experimental environment for further work. The neurotoxin tetrodotoxin (TTX; 3 × 10−6 M) failed to abolish or modify these spontaneous contractions although excitatory and inhibitory responses to 5-hydroxytryptamine (5-HT) and acetylcholine (ACh) respectively were demonstrated. Electrical recordings showed that spontaneous contractions were mediated by slow membrane depolarizations upon which spike-like potentials were often superimposed. 5-HT was shown to mediate its excitatory effect via membrane depolarization and an increase in the frequency of both slow depolarization and spikes. In contrast, inhibition by ACh was accompanied by membrane hyperpolarization and loss of all regenerative electrical activity. Electric field stimulation of the preparation using a range of stimulus parameters failed to demonstrate a functional motor innervation to the somatic muscle.
Action of praziquantel on Grillotia erinaceus metacestodes (Cestoda: Trypanorhyncha) in vitro
Authors: Ward S. M. , Allen J. M. , McKeer G. 
Published: June 2009

SUMMARYIsometric tension recordings and the single sucrose-gap technique were used to record mechanical and electrical activity of somatic muscle from G. erinaceus metacestodes in vitro. Praziquantel (≥ 10−6 M) raised baseline tension and largely abolished spontaneous fluctuations in tension. The effect of the drug was critically dependent on the presence and availability of calcium in the bathing medium. In calcium-free solution or in the presence of manganese or lanthanum (10 mm) praziquantel failed to induce a rise in baseline tension. Electrical recordings of somatic muscle activity showed the action of praziquantel to be accompanied by membrane depolarization and loss of slow depolarizations and spikes. Tegumental membrane potential, as measured by microelectrodes, was not affected by the drug. These results suggest that in vitro praziquantel causes contraction of the somatic muscle of G. erinaceus by membrane depolarization and influx of extracellular calcium.
Genetic control of liability to infection withNematospiroides dubiusin mice: selection of refractory and liable populations of mice
Authors: Brindley P. J. , Dobson C. 
Published: June 2009

SUMMARYQuackenbush strain and wildMus musculuswere assayed for their liability to primary infection with 100 LaNematospiroides dubiususing an experimentally derived selection index. Refractory and liable colonies of mice were established over 5 generations. Liability toN. dubiusinfection was found likely to be controlled by several genes; the heritability (h2) of this trait was estimated at 0·45. Positive linear correlation was found between the number of parasite eggs voided and the number of adultN. dubiusrecovered, negative correlation between the pre-patent period of infection in days and the number of parasite eggs voided and positive correlation in 2 of 5 generations between live mouse body weight and the number of adultN. dubiusrecovered. Further, positive correlation was found between the liability of female mice toN. dubiusand their progeny litter size number. The genetic mechanisms controlling the liability trait and the possible evolutionary significance of these results are discussed.
An improved technique for the cryopreservation of Onchocerca microfilariae
Authors: Ham P. J. , Townson S. , James E. R. , Bianco A. E. 
Published: June 2009

SUMMARYExperiments describe the use of ethanediol to store Onchocerca microfilariae in liquid nitrogen. The technique involves a 2-stage incubation of the parasites at 37 °C and 0 °C in ethanediol, before rapid cooling to − 196 °C. Viability has been assessed by motility, by migration in a proxy host and by development to the infective stage in the insect vector. A total of 71–79% of the cryopreserved microfilariae was shown to be viable compared to unfrozen controls. The technique is simple, inexpensive and very effective when compared to previous cryopreservation procedures for microfilariae and should be particularly suited for use under field conditions.
The initial stages of infection of cattle cells with Theileria parva sporozoites in vitro
Authors: Stagg D. A. , Dolan T. T. , Leitch B. L. , Young A. S. 
Published: June 2009

SUMMARYLarge numbers of Theileria parva sporozoites were separated from Rhipicephalus appendiculatus adult ticks by filtration and were then concentrated by centrifugation. The sporozoites were incubated at 37 °C with leucocytes from 6 cattle of Bos indicus and B. taurus types. Giemsastained smears and living preparations under interference contrast microscopy were used to follow the course of the infection of the leucocytes with sporozoites. Sporozoites were seen to attach rapidly to about 25% the leucocytes which they penetrated. After penetration by the sporozoites the morphology of the cells changed to show an increase in cytoplasm and an enlargement of the Golgi apparatus, with which the parasite appeared to become associated. The early intracellular or preschizont stages resembled Babesia parasites. From day 3, the parasite showed the typical morphology of the macroschizont of T. parva. Multiple infections were frequent and up to 8 schizonts were observed arranged around the Golgi apparatus. Multiply infected cells did not survive in culture but some of the cells infected with a single parasite divided to produce 2 infected daughter cells and infected lymphoblastoid cell lines were established in all 21 attempts.
Response of hypersensitized guinea pigs to the feeding ofAmblyomma americanumticks
Authors: Brown S. J. , Knapp F. W. 
Published: June 2009

SUMMARYGuinea pigs acquired resistance to the feeding of immatureAmblyomma americanumticks after a single infestation. The initial larval and nymphal feedings resulted in cumulative mortalities of 27·2 and 28·9%, respectively. The second and third larval infestations yielded cumulative mortalities of 50·5 and 52·4%, compared to 18·9 and 24·4% cumulative mortality from controls. Second and third nymphal feedings resulted in 75·7 and 73·4%, and ticks from controls exhibited 36·6 and 34·7% cumulative mortality. The development of host resistance adversely affected tick feeding and resulted in abnormally coloured ticks and a protracted moulting period with a marked decrease in moulting ability. Histological examination of tick feeding sites on guinea pigs challenged twice revealed greater cavity and lesion sizes in hosts fed upon by nymphs than larvae. The primary cell type within these feeding sites were basophils at 12 h post-attachment, but by 72 h post-attachment eosinophils were dominant. The upper epidermal layer adjacent to both larval and nymphal feeding ticks had accumulations of basophils with a few eosinophils. Lymphocytes may have been involved in the resistance response because local lymph nodes in resistant hosts were much larger than in uninfested and singly infested hosts. Some of these nodes had secondary germinal centres.
Trypanosoma (Schizotrypanum) assiutis sp.nov. from the house mouse Mus musculus, with a comparative study on Trypanosoma (Schizotrypanum) vespertilionis of the Egyptian bat Vesperugo kuhli
Authors: Fahmy M. A. M. , Abedl-Rahman A. M. , Khalifa R. 
Published: June 2009

SummaryOn examination of a house mouse (Mus musculus) trapped in Rifa village (Assiut Governorate), a Trypanosoma cruzi-like trypanosome was encountered which differed from the cruzi-like trypanosomes of local bats. It appeared to be a hitherto unknown species for which the name Trypanosoma (Schizotrypanum) assiutis sp.nov. is suggested.
The measurement ofAscaris suumprotein by radioimmunoassay in sera from patients with helminthiasis and with gastrointestinal diseases
Authors: Tanaka K. , Kawamura H. , Tohgi N. , TsujI M. , Miyachi Y. , Miyoshi A. 
Published: June 2009

SUMMARYIn this study, we have developed a reliable radioimmunoassay (RIA) forAscaris suumprotein (Asp) and have measured the serum concentration of Asp in control subjects and in patients with helminthiasis and a variety of gastrointestinal diseases. The cross-reactivities of Asp antibody with other helminth worm antigens were also measured by RIA.Ascaris lumbricoidescontained approximately the same amount of Asp antigenic substance as didAscaris suum. Toxocara canishad a high concentration of a substance partially cross-reactive with Asp. Small amounts of substance cross-reacting with Asp were also exhibited by Anisakis larvae,Schistosoma japonicumandTaenia saginata. However, no cross-reactivities ofFasciola hepaticaandParagonimus westermaniwith Asp were observed in this study. Almost all the serum levels of Asp from normal control subjects were below the sensitivity of this RIA (10 ng/ml). High concentrations of Asp were observed in sera from patients with ascariasis (64.5±18.8 ng/ml: mean ± S.E.), anisakiasis (75.2±28.0 ng/ml), toxocariasis (78.4±31.3 ng/ml) and schistosomiasis japonica (14.3±3.4 ng/ml). Asp levels in sera from patients with other helminthiasis were not significantly high. From these findings, it was suggested that RIA for Asp may not be specific for diagnosis of ascariasis, but might be a suitable screening method for patients with some kinds of helminthiasis. Interestingly, high concentrations of Asp were also observed in sera from patients with ulcerative colitis (24.8±2.5 ng/ml) and Crohn's disease (19.8±5.2 ng/ml), but Asp levels from 7 other gastrointestinal diseases seemed not to be significantly high. These findings remain unexplained but may derive from cross-reactivities between helminthic and gut mucosal antigens.
In vitro feeding of Dermacentor andersoni (Stiles): effects of histamine and other mediators
Authors: Paine S. H. , Kemp D. H. , Allen J. R. 
Published: June 2009

SUMMARYFemale Dermacentor andersoni were induced to feed on defibrinated bovine blood through fixed mouse skin membranes. Their feeding behaviour was recorded electronically, the tick being incorporated into the circuit and acting as a variable resistor during the periods of sucking, salivation and rest. Recordings of the feeding behaviour of these ticks were similar to those of ticks feeding on rabbits. Known concentrations of histamine, serotonin, dopamine, prostaglandin E1 and prostaglandin F2α were added singly or in combination to the feeding medium of ticks attached to the mouse skin membrane. Addition of both histamine and serotonin was followed by a significant reduction in the amplitude or recordings associated with sucking and salivation. The concentration of mediators producing this effect was less than 10 mM, a concentration comparable to that of histamine found locally in the skin of tick-resistant guinea-pigs. Comparisons are made between the effects produced by these mediators in ticks and the effects of serotonin and other amines known to produce modulation of complex behaviour patterns in other invertebrates.
Patterns of sexual reproduction among parasitic platyhelminths
Authors: Nollen P. M. 
Published: June 2009

SUMMARYPrevious studies on the spermatogenesis and oogenesis of digeneans, monogeneans and cestodes are reviewed, including those in which isotopic labelling techniques have been utilized in order to determine the temporal duration of spermatogenic development stages. Similar labelling experiments have also provided information on the development and movement of oocytes in the female reproductive tract as well as indicating patterns of cell division and development in vitelline glands. The literature relating to the inseminative behaviour of parasitic platyhelminths is considered from a number of viewpoints including the patterns of cross-and self-insemination that occur in hermaphroditic digeneans, the mating behaviour of dioecious schistosomes, spermatophore production and insemination among monogeneans and the inseminative behaviour of polyzoic cestodes. The implications of selfing among parasitic platyhelminths are considered with respect to possible genetically deleterious consequences. In addition, consideration is given to the mechanisms underlying the fact that some species require cross-insemination or at least the presence of another worm in order to undergo normal growth and sexual development. Finally, experimental studies are reviewed which shed light on the strength of the barriers against hybridization that exist between well-defined species of parasitic platyhelminths.