bluuebunny/crossref_metadata_2025_split huggingface dataset:
The formation, structure and histochemistry of the metacercarial cyst of three species of digenetic trematodes
Authors: Pike Alan W. , Erasmus D. A. 
Published: June 2009

Cercariae of Psilotrema oligoon and Notocotylus attenuatus encyst free to form multilayered, hemispherical cysts. The former consists of four layers in which the innermost (layer 4) is divided into two, chemically and structurally different, areas. Cysts of the latter have three layers in which the innermost (layer 3) is again divided into two chemically different parts. A third cyst, produced by the encystment of Cercaria tarda in the tissues of Limnophilus flavicornis, is spherical and contains three layers (of which the outermost was not studied).All of the cysts studied contain a high proportion of protein, which in some layers occurs combined with carbohydrates. In both free-encysting species the two outer layers are produced by expansion of a non-cellular layer covering the integument and the innermost layer is produced by secretion of bâtonnets from a layer of cells lying beneath the body wall. Cysts of P. oligoon are divided into two separate parts, each having two layers, whereas those of N. attenuates consist of a single three-layered wall. The innermost layer in both consists of a protein with disulphide and sulphydryl linkages, and in the cyst of P. oligoon it has a circular ventral area containing carbohydrates. A similar carbohydrate-containing area occurs in the innermost layer of the cyst of N. attenuatus but as a ventro-lateral ring of material. The cyst of Cercaria tarda is also predominantly proteinaceous and stains intensely for RNA.
Studies on the protein metabolism of cestodes 2. Effect of free dietary amino acid supplements on the growth of Hymenolepis diminuta
Authors: Mettrick D. F. 
Published: June 2009

The dry weight, nitrogen content, and total carbohydrate content of Hymenolepis diminuta were studied after a period of 15 days growth in rats, maintained on different diets. The special diets were fed during the last 7 days of this period.Using equal iso-molecular quantities, seven amino acids, representing the different classes of neutral amino acids, acidic amino acids and basic amino acids, have been screened for their effect on worm growth when added as free dietary supplement to the different diets. All of them, to a greater or lesser extent, had significant effects on worm growth.The award of a research grant by the Standing Advisory Committee for Medical Research in the British Caribbean is gratefully acknowledged. I am also indebted to Professors J. C. Waterlow and C. von Holt for the loan of equipment in order to carry out the carbohydrate and nitrogen determinations, to Professor I. M. Good-body for his continued interest and support, and to the Rippel Foundation for research facilities.
The occurrence of Diplozoon paradoxum Nordmann, 1832 (Trematoda: Monogenea) in certain waters of northern England and its distribution on the gills of certain Cyprinidae
Authors: Wiles Michael 
Published: June 2009

The monogenean Diplozoon paradoxum occurs on Abramis brama, Gobio gobio, Phoxinus phoxinus and Rutilus rutilus in northern England. In any one area, the infection is present in some waters but absent in others and predominates in rivers rather than in ponds or reservoirs.D. paradoxum is randomly distributed on the gills, sides of the gill apparatus, hemibranchs and surfaces of primary lamellae of G. gobio, P. phoxinus and R. rutilus (except for P. phoxinus where inner hemibranchs carry more worms), but prevails on median sectors of the gills of these hosts. In A. brama the parasite is more numerous on certain gills, on the right side of the gill apparatus, and on the inner hemibranchs, but is randomly disposed on primary lamellar surfaces and along the gills. Except on G. gobio attachment is predominantly to two primary lamellae rather than one. This may reduce dislodging effects of the gill ventilating current by leaving portions of the lamellar surfaces unoccupied and allowing unimpeded flow in these regions.This work was conducted during tenure of a Science Research Council Research Studentship. Research facilities in the Department of Zoology, University of Leeds, were kindly provided by Professor J. M. Dodd. Other facilities in the Biological Station, St John's, Newfoundland, were provided by the Director, Dr W. Templeman. Statistical advice offered by Dr E. Broadhead, Department of Zoology, and Professor C. L. Oakley, Department of Bacteriology, both of the University of Leeds, is gratefully acknowledged. I am indebted to Dr R. Wynne Owen, Department of Zoology, for constant advice and encouragement and for critical reading of the manuscript.
Acanthobothrium quadripartitumsp.nov. (Cestoda: Tetraphyllidea) fromRaja naevusin the North Sea and English Channel
Authors: Williams H. Harford 
Published: June 2009

Acanthobothrium quadripartitumsp.nov., from the intestine ofRaja naevusin the North Sea and English Channel is described and figured. In adult morphology it resemblesA. brevissimeLinton, 1908, more closely than any other known species of the genus.A. quadripartitumis one of the smallest known tapeworms and occurs in numbers of up to 13000 in one intestine. Preliminary observations indicate that it has little damaging effect on the epithelial cells of the host's mucosa.I am indebted to Professor V. C. Wynne-Edwards for providing excellent research facilities and to the Director and Staff, in particular Dr B. B. Rae, Dr Z. Kabata and Mr Stuart Pirie, Marine Laboratory, Aberdeen, for laboratory space and material.
Naturally occurring antibodies to the cuticle of nematodes
Authors: Hogarth-Scott R. S. 
Published: June 2009

Studies based on the mixed antiglobulin reaction have shown that γ-globulin is adsorbed from normal human sera by the cuticle of parasitic nematodes. Using antiglobulins specific for IgA, IgM and IgG, it was possible to demonstrate uptake to titres of 4, 64 and 128, respectively. Adsorption continued for at least 24 h, and the responsible immunoglobulins could be absorbed from the sera by nematode preparations.A comparison of normal human sera with sera from cases of ascariasis and visceral larva migrans revealed that there was no significant difference between the titre of anti-cuticular immunoglobulins in normal sera or sera from helmin-thiases. It is suggested that these immunoglobulins adsorbed by the nematode cuticle represent cross-reacting, naturally occurring antibodies.I am sincerely grateful to Professor R. R. A. Coombs, F.R.S., for his help, advice and encouragement, and to Mr M. J. Eburne for splendid technical assistance.
The effect of sulphaquinoxaline and amprolium on the life cycle of Eimeria adenoeides Moore and Brown, 1951, in turkey poults
Authors: Warren E. W. , Ball S. J. 
Published: June 2009

Sulphaquinoxaline fed at 0·0125%, w/w, in the food principally affects the development of the second generation schizonts of Eimeria adenoeides in turkey poults. Amprolium, at the same concentration, acts on the first generation. Both drugs appear to exert some effect on gametogony. The activity of sulphaquinoxaline against this species is inhibited by p-aminobenzoic acid, and the activity of amprolium by thiamine.We are grateful to Mrs B. M. Mitchell and Miss C. Hitchcock for technical assistance and to Mr A. D. Speed for the histological preparations.
The effects of computer-controlled shadow stimuli on the success of cercarial transmission by Cryptocotyle lingua (Digenea: Heterophyidae)
Authors: Rea J. G. , Irwin S. W. B. 
Published: June 2009

SUMMARYPectoral fins from juvenile rainbow trout (Oncorhynchus mykiss) were used in a bioassay, the object of which was to quantify the effect of simulated shadow stimuli on the transmission success of the cercariae. For a period of 60 min, parasites and fins were exposed to a sequence of computer-controlled shadow stimuli, continuous light or total darkness, and subsequently the number of infections was counted. Trials were conducted with cercariae 1, 12 and 24 h old. Within the constraints of the experimental procedure, shadows were found to increase significantly the number of infections achieved by the 12-h-old parasites. As the cercariae aged, their ability to infect host tissue declined. The relevance of these results to transmission in the natural environment is discussed.
Population genetics of Trypanosoma brucei in Central Africa: taxonomic and epidemiological significance
Authors: Truc P. , Tibayrenc M. 
Published: June 2009

SUMMARYIn order to estimate the value of population genetics for both the taxonomy of trypanosomes belonging to the species Trypanosoma brucei and a better understanding of Human African Trypanosomiasis (HAT), we undertook a cellulose acetate electrophoresis isoenzyme study involving 55 stocks isolated from man and animals in Congo, Zaire and Cameroun. Out of the 24 loci surveyed, 15 exhibited variability, which made it possible to delimit 23 zymodemes, divided into 2 groups. The first group equated to the classical subspecies Trypanosoma brucei gambiense, while the second corresponded to the classical subspecies Trypanosoma brucei brucei. These results broadly agree with the current taxonomy, and are corroborated by RFLP analysis of kDNA. Statistical analysis indicates a basically clonal reproduction system of the trypanosomes in the area studied; the zymodemes are equivalent to natural clones (or a family of closely related clones), stable in space and time. Epidemiological hypotheses are proposed according to the geographic distribution of the clones in this area.
Leishmaniasis epidemiology: all down to the DNA
Authors: Blackwell J. M. 
Published: June 2009

SUMMARYApplication of quantitative methods to the study of leishmaniasis epidemiology has allowed Dye (1992) to pinpoint important biological parameters which, if they could be accurately measured in the field, would contribute most to our knowledge of the spread of disease and key targets for control. Three areas in which laboratory-based research could impact most on leishmaniasis epidemiology were highlighted by Dye (1992): (i) the development of accurate diagnostic tools which can distinguish between current and past infection; (ii) to determine the underlying molecular/genetic basis to virulence polymorphisms in the parasite and study these in the context of field epidemiological studies; and (iii) to provide the molecular tools to measure genetic variation in resistance to infection in humans and in reservoir hosts of disease. This paper describes current progress in attaining these goals, highlighting first the work on isolation and field application of genomic and kDNA probes for species-specific diagnosis, and the development of PCR-based assays which can be performed under field conditions. At a more preliminary stage, studies are described in which variability in the major molecular determinants of virulence (lipophosphoglycan, GP63, and members of the HSP7O family of stress proteins) identified through studies of laboratory models of infection, is being measured in primary field isolates ofLeishmania peruviana. To complete the picture, current progress in identifying and cloning the genes which control host resistance to leishmanial infection is described, along with field studies of multicase families of human disease in which linkage analysis using marker genes from the chromosomal regions bearing these genes can be used to find evidence for their role in determining disease phenotypes in man. The leishmaniasis epidemiology will be all down to the DNA. projected view from these studies is that the future of leishmaniasis epidemiology will be all down to the DNA.
Diarrhoeal disease in early childhood: experiences from Sierra Leone
Authors: Hodges M. 
Published: June 2009

SUMMARYIn the Freetown area of Sierra Leone, the proportion of children under five years of age dying from diarrhoea-associated conditions has decreased since the 1970s from 4% to 3%. This reduction relates to children between 12 months and 5 years; deaths associated with diarrhoeal disease in infancy do not appear to have decreased significantly. Currently, 2% of children die in infancy and a further 1% before their fifth birthday from diarrhoeal diseases. Thirty-one percent of short-term growth-faltering in children under five years of age is attributed to diarrhoeal disease. Reasons for improvement in mortality may include the implementation of a National Diarrhoeal Diseases Control Programme and improved case management; some 55% of cases of acute diarrhoea in Freetown now receive oral rehydration therapy. Morbidity and mortality are influenced by the seasons. This is likely to be related to the fact that the nutritional status of children shows a significant deterioration in the early rainy season. At this time incidence of severe diarrhoea warranting hospital admission and diarrhoea mortality rates in hospital and at a Rehydration Center increased significantly. On the other hand, the presentation of dehydrating diarrhoea is greatest in the driest months of the year. Progress in the rural areas of Sierra Leone may not have been so evident although 60% of the population now have access to primary health units within 4 miles and efforts to increase host resistance have included the measles immunization programme which currently protects 60% of under-fives nation-wide. Efforts to reduce the transmission of pathogens have meant increasing access to safe water to 22% and to improved sanitation to 35% in rural areas of Sierra Leone. The sustainable prevention and control of diarrhoeal diseases in developing countries depends also upon increasing levels of adult literacy especially of women.
Density-dependent acquired resistance to ticks in natural hosts, independent of concurrent infection with Babesia microti
Authors: Randolph S. E. 
Published: June 2009

SUMMARYThe question of whether the known immunosuppressive effects of Babesia microti may disrupt the development of acquired resistance to its tick vector, Ixodes trianguliceps, in natural rodent hosts (Clethrionomys glareolus), and thus enhance thedisease transmission potential, is addressed experimentally. The results show for the first time that natural hosts can acquire resistance to ticks; that this acquired resistance is manifested chiefly by a strongly density-dependent reduction in the percentage of attached larvae that engorge; that the density dependence is quantitatively similar whether the host receives occasional large tick challenges or frequent low infestations; but that infection with B. microti does not disrupt this pattern of acquired resistance. Of two important natural host species, Apodemus sylvaticus can support repeated infestations of I. trianguliceps, but is a poor host to B. microti, while C. glareolus develops acquired resistance to the tickvector, but supports much higher-level, longer-lasting B. microti infections.
Effect of metacestodes of Hymenolepis diminuta on storage and circulating carbohydrates in the intermediate host, Tenebrio molitor
Authors: Kearns J. Y. , Hurd H. , Pullin A. S. 
Published: June 2009

SUMMARYThe metamorphosis of oncospheres of the rat tapeworm, Hymenolepis diminuta, to mature metacestodes induces several pathophysiological effects in the intermediate host, Tenebrio molitor (Coleoptera). Previous investigations have failed to elucidate the mechanism responsible for changes in the host reproductive physiology and behaviour. This work forms part of an assessment of the degree to which nutrient resource management may be involved in these interactions. We report that developing metacestodes exert a pronounced effect upon host carbohydrate reserves and also alter circulating carbohydrate titres at some stages post-infection. Biochemical studies of fat body glycogen demonstrated a significant depletion of reserves as early as 3 days post-infection in males and 5 days post-infection in females. Gas chromatography revealed trehalose to be the predominant haemolymph carbohydrate, titres being significantly elevated in male beetles 5 and 9 days post-infection and in females 12 days post-infection. Metacestodes had no effect on glucose concentrations in male or female beetles.
Immune responses of Texel sheep to excretory/secretory products of adult Haemonchus contortus
Authors: Schallig H. D. F. H. , van Leeuwen M. A. W. , Hendrikx W. M. L. 
Published: June 2009

SUMMARYThe excretory/secretory (E/S) products of adult Haemonchus contortus comprise of at least 15 polypeptides with molecular weights ranging from 10 to > 100 kDa. These E/S products induce an immune response in infected Texel sheep, as demonstrated by specific IgGI levels and a significant lymphocyte proliferation index. Moreover, immunoblotting analysis revealed that sera of primary H. contortus-infected sheep specifically recognize a 24 kDa E/S product. In addition, sera of challenged sheep react strongly with a 15 kDa E/S product. The other E/S products of H. contortus showed immunoreactivity with serum samples of Haemonchus-infected sheep as well as with samples of sheep harbouring other trichostrongylid infections. These cross-reacting epitopes are the main cause of the lack of specificity of an E/S material- based ELISA. This ELISA can differentiate Haemonchus infections from Nematodirus battus infections, but not from Ostertagia circumcincta or Trichostrongylus colubriformis infections.
A 69 kDa immunodominant antigen ofTrypanosoma (Nannomonas) congolenseis homologous to immunoglobulin heavy chain binding protein (BiP)
Authors: Boulangé A. , Authié E. 
Published: June 2009

SUMMARYAn immunodominant antigen inTrypanosoma congolense-infected cattle is a 69 kDa protein which is conserved among species and developmental stages of African trypanosomes. Immunoscreening of a cDNA expression library identified a 2·35 kbp clone which contains a complete open reading frame encoding a protein of 653 amino acids with a predicted molecular mass of 71 kDa. Protein sequence analyses revealed 45–65% identity with hsp70s from a broad range of organisms, the highest homology being with the mammalian BiP (immunoglobulin heavy chain binding protein). The 69 kDa trypanosome protein shares with other BiP-related molecules two characteristics that are associated with their localization in the endoplasmic reticulum and their function as chaperonins, i.e. a hydrophobic N-terminal signal sequence and a conserved C-terminal tetrapeptide (X)DEL. Divergence between the 69 kDa antigen and other BiP-homologues occurs in the C-terminal region. This may be responsible for the high immunogenicity of the trypanosome protein. The gene for the 69 kDa antigen appears to be present as a cluster of several copies which are not organized in tandem repeats. It is expressed in all developmental stages ofT. congolense, but the specific mRNA levels are higher in metacyclics than in other stages.
Proteinase activity in the plerocercoid of Proteocephalus ambloplitis (Cestoda)
Authors: Polzer M. , Overstreet R. M. , Taraschewski H. 
Published: June 2009

SUMMARYHost invasion and tissue migration of several helminths have been linked to expression and release of parasite-derived proteinases. The plerocercoid of the cestode Proteocephalus ambloplitis can migrate into the visceral organs or, in the case of bass, from them into the intestinal tract of the same individual fish. It does this within a few hours, aided by secretion of a substance from its apical gland. Proteinase activity in this plerocercoid, obtained from the host liver, was defined by pH optimum, by substrate and inhibitor specificity, and by electrophoretic and chromatographic techniques. Homogenates of plerocercoid contained a metalloproteinase exhibiting a molecular weight of 30000 determined by gelatin substrate gel electrophoresis. Peak activity of this proteolytic enzyme in gel filtration fractions when azocoll was used as substrate then corresponded to a molecular weight of 31500. The proteinase showed collagenolytic, haemoglobinolytic and slight elastinolytic activity, and it had a pH optimum at 9·0. Enzyme activity could be inhibited by various chelating agents. The metalloproteinase identified in this study constitutes the only enzyme class present in this larval stage of P. ambloplitis. We suggest that the plerocercoid's metalloproteinase is the substance secreted from the apical organ, necessary for the previously recognized tissue migration phase. This enzyme might also have a nutritional function.
In vitropolarization of carp leucocytes in response to the blood flukeSanguinicola inermisPlehn, 1905 (Trematoda: Sanguinicolidae)
Authors: Richards D. T. , Hoole D. , Lewis J. W. , Ewens E. , Arme C. 
Published: June 2009

SumaryAnin vitroassay was used to determine the effects ofSanguinicola inermisadults and cercariae on the polarization responses of pronephric leucocytes of carp. Leucocytes were isolated and exposed to live adult flukes or cercariae for up to 48 h. Differences in polarization responses were related to the presence of the parasite, the presence or absence of carp serum and the time of incubation. The mean proportions of cells exhibiting polarization in unstimulated controls ranged from 5 to 30% over the experimental period. Within 15 min of exposure to adults or cercariae, significant increases in mean polarization responses were observed of up to 75% and levels remained higher than control values for over 24 h. Overall, the presence of normal carp serum, either untreated or heat inactivated, did not enhance the polarization responses of leucocytes incubated with only cercariae or adults. However, between 0·25 and 3 h, the presence of carp serum with cercariae significantly enhanced polarization responses when compared with cells incubated with cercariae alone.
Spontaneous release of cysteine proteinases but not of pore-forming peptides by viableEntamoeba histolytica
Authors: Leippe M. , Sievertsen H. J. , Tannich E. , Horstmann R. D. 
Published: June 2009

SUMMARYInvasive properties of pathogenicEntamoeba histolyticahave been postulated to depend on the secretion or release of cysteine proteinases and pore-forming peptides (amoebapores) by trophozoites. To establish whether such toxic molecules are released by viable trophozoites or upon cellular disintegration, amoebae were maintained in various culture media, and activities in supernatants were monitored over time in correlation to cellular integrity. By measuring the release of the cytoplasmic marker enzyme NADP+-alcohol dehydrogenase, it became apparent that release of amoebapore was accompanied by cellular disintegration. In contrast, considerable quantities of cysteine proteinases were found to be present in culture supernatants also when amoebae remained intact. Treatment of amoebae with concanavalin A, bacterial lipo-polysaccharides or the calcium ionophore A23187 did not result in amoebapore secretion suggesting that here target cell contact is required as an essential stimulus.