bluuebunny/crossref_metadata_2025_split huggingface dataset:
The oncomiracidium and post-oncomiracidial development of the hexabothriid monogeneanRajonchocotyle emarginata
Authors: Wiskin Maureen 
Published: June 2009

SUMMARYA description is given of some features of the embryonic development, the structure of the oncomiracidium and the postlarval development ofR. emarginata, a hexabothriid parasite on the gills ofRaia clavata.There are three phases in the larval development of the haptor ofRajonchocotyle:an oncomiracidial or marginal hook stage, a hamulus stage and a sucker stage. Neither the embryo nor the oncomiracidium ever possesses more than five pairs of marginal hooks and marginal hooks I (the posterior-most pair) are considered to be missing. The marginal hooks develop within distinct binucleate oncoblasts. During the early stages of post-oncomiracidial growth the secondary attachment organs of the haptor are formed and it is only after the completion of the development of the haptor that the reproductive organs begin to appear. Firstly, a pair of hamuli is acquired, followed by four pairs of suckers, which form in posterior-anterior succession at the site of marginal hooks III-VI. The first pair of suckers remains unarmed while the other three pairs acquire hooked sclerites and become the main functional attachment organs of the adult. As the first pair of suckers appears the posterior part of the haptor lengthens to form a caudal appendage. Hexabothriids are considered to show closer affinity to the 8-suckered chimaericolids and diclidophorids than to the 6-suckered polysto-matids, the unarmed suckers representing a simplification, by loss of the sclerite and reduction in sucker size, of an originally armed sucker.I would like to express my thanks to Dr J. Llewellyn for his interest and for much helpful discussion.Thanks are also due to the Director and Staff of the Marine Biological Association at Plymouth, in particular Mr J. E. Green for material and assistance, and to Dr A.j Brinkmann, of the Department of Zoology, University of Bergen, for supplying specimens ofSqualonchocotyle borealis.
Codon usage and bias among individual genes of the coccidia and piroplasms
Authors: Ellis J. T. , Morrison D. A. , Avery D. , Johnson A. M. 
Published: June 2009

SummaryCodon usage has been analysed in individual gene sequences, derived from a variety of parasitic protozoa in the class Sporozoa of the phylum Apicomplexa using metric multidimensional scaling. The two groups of codon usage patterns detected reflect the two main subgroups of organisms studied (the coccidia and the piroplasms), and it is the pattern usage of synonymous codons that has the largest influence on overall codon usage in the individual genes, rather than being the pattern of amino acid composition of the gene product. The magnitude of the codon usage bias in the sequences was determined using three commonly used indices – NC', GC3sand B. In general, although relatively low levels of codon usage bias were detected in these gene sequences, codon usage bias does explain at least some of the codon usage patterns observed. Codon usage bias was observed to be dependent on the overall base composition of the genes analysed, which in turn was reflected in the types of codons that were either over-or under-represented in the nucleotide sequences. keeping with observations on prokaryotic organisms, it is speculated that the codon usage patterns detected in these parasitic protozoa are the result of directional mutation pressure on the base composition of the genomic DNA.
The effect of the tetrathyridia of Mesocestoides corti on the livers and peripheral blood of three different strains of mice
Authors: Riley S. L. , Chernin J. 
Published: June 2009

SummaryThree strains of male and female mice, CFLP, BALB/c and CBA/ca, were infected i.p. with the tetrathyridia of Mesocestoides corti and examined in groups of 5 at 0, 7, 14, 21, 28 and 42 days post-infection. At post-mortem the numbers of parasites both loose in the peritoneal cavity and in the liver tissue were counted, the livers weighed fresh and sections of liver stained to examine the inflammatory response, encapsulation of the tetrathyridia and for eosinophils, neutrophils, mast cells and plasma cells. BALB/c mice had significantly more parasites loose in the peritoneal cavity than CFLP and CBA/ca mice. Infected livers of all three strains were significantly heavier than control livers; the heaviest livers were those of the CFLP followed by the CBA/ca mice which also showed the greatest rate of weight increase. The tetrathyridia from the peritoneal cavities of the CBA/ca and CFLP mice were covered with a ‘mucilage-like’ substance. Tetrathyridia within the host capsules of the CBA/ca mice contained host cells. There was no strain difference with regard to numbers of tetrathyridia in the liver but male mice harboured significantly more parasites than females. Differences in the numbers of cell types within the liver were detected between the strains but no one strain showed any consistent pattern. There was an overall increase in total white blood counts as well as an increase in the number of eosinophils, monocytes, neutrophils and lymphocytes during the course of the infection.
Dynamics of the interaction between the parasitic isopod, Anilocra pomacentri, and the coral reef fish, Chromis nitida
Authors: Adlard R. D. , Lester R. J. G. 
Published: June 2009

SummaryField and laboratory investigations into the effect of the parasitic isopod Anilocra pomacentri (Cymothoidae) on the population dynamics of the reef fish Chromis nitida (Pomacentridae) were carried Out at Heron Island, Great Barrier Reef, Australia. Fish carried a single adult parasite just posterior and dorsal to the eye either to the right or to the left of the midline. The adult parasite was overdispersed among fish on patch reefs (dispersion factor, k = 0·69). Sequential field observations on a single cohort of fish showed that parasites significantly depressed growth, reproduction, and survivor-ship. The von Bertalanffy growth coefficients (a measure of somatic growth) were 0·10 for parasitized fish compared with 0·17 for non-parasitized fish. Female fish carrying the parasite produced only 12% of the number of eggs produced by non-parasitized fish of the same size. In the field, the mortality of infected juvenile C. nitida (LCF 15–30 mm) was estimated to be at least 88% in the first 70 days after recruitment of the fish. The mortality of uninfected recruits over the same period was 66%. In laboratory trials, the mortality associated with the infection of juvenile fish by larval parasites ranged from 78% for small fish (mean LCF 15·0 mm) to 28% for larger fish (mean LCF 24·9 mm) within 4 days of experimental infection. This is one of the few studies that evaluates the effect of a parasite on a population of fish in the field.
Characterization of a HMG2-like protein fromSchistosoma mansoni
Authors: Fantappié M. R. , Rumjanek F. D. 
Published: June 2009

SUMMARYAn HMG2-like protein was purified from nuclear extracts of adultSchistosoma mansoni. Investigation of the amino acid composition of the schistosome HMG2-like protein showed that glutamic acid, glycine, aspartic acid and lysine were the most abundant. Carbohydrate analysis showed that the HMG2-like protein presented a low degree of glycosylation, galactose or glucose being the major monosaccharide constituent. Incubation of live schistosomes with32P followed by isolation of nuclear proteins showed that the HMG-2 like protein could be phosphorylated. Partial sequence analysis of cyanogen bromide peptides revealed the occurrence of a phosphorylation consensus motif. The schistosome HMG2-like protein was found to bind preferentially to single-stranded DNA. The results suggest that the major non-histoneS. mansoninuclear protein belongs to the HMG family.
Molecular systematics in the acanthocephalan genus Echinorhynchus (sensu lato) in northern Europe
Authors: Väinölä R. , Valtonen E. T. , Gibson D. I. 
Published: June 2009

SUMMARYNew biological species and high levels of inter- and intraspecific genetic divergence were discovered in an allozyme study of some North European members of the acanthocephalan genus Echinorhynchus (sensu lato), parasites of fish and malacostracan crustaceans. (i) A strong differentiation between the marine E. gadi and the fresh- and brackish-water E. salmonis (genetic identity I ≃ 0) supports a generic distinction between these taxa; however, the subdivision would not entirely concur with the concepts of Echinorhynchus (sensu stricto) and Metechinorhynchus suggested earlier. (ii) Samples of E. gadi from the Baltic, Norwegian and North Seas included three distinct, partially sympatric biological species (spp. I–III; I ≃ 0·5). (iii) E. bothniensis, previously only known from the northern Baltic Sea, represents a complex of freshwater taxa with an intermediate host relationship to the ‘glacial relict’ Mysis spp. and with a distributional and host analogy to the North American E. leidyi. A population in a northern lake in the Barents Sea basin is closely related to E. bothniensis of the Baltic area, but is probably specifically distinct; the divergence between these populations (I ≃ 0·6) is similar to that between their Mysis host species. (iv) Considerable intraspecific differentiation (Fst = 0·25), probably reflecting post-glacial population bottlenecks, was found between Baltic and nearby lacustrine E. bothniensis, and between Atlantic and Baltic E. gadi sp. I.
The effects of chloroquine on the infectivity of chloroquine-sensitve and -resisant populations of Plasmodium yoelii nigeriensis to mosquitoes
Authors: Ichimori K. , Curtis C. F. , Targett G. A. T. 
Published: June 2009

SUMMARYSubtherapeutic doses of chloroquine have been reported to enhance infectivity of drug-resistant Plasmodium species to their vectors. In this investigation, Plasmodium yoelii nigeriensis N67 strain showed enhanced infectivity to mosquitoes when stimulated by chloroquine. Both sensitive and resistant clones were derived from the N67 strain by dilution, showing that this strain is polymorphic for the resistant trait. A resistant subline was derived by selection under drug pressure from a chloroquine-sensitive clone, but neither the sensitive nor the resistant clones or sublines showed enhancement of infectivity in the presence of chloroquine. This suggests that the enhancement of infectivity shown by the N67 strain is a response to chloroquine stimulation shown only by certain of the genotypes within it, and that this response to chloroquine is not a trait causally connected with the genes coding for chloroquine resistance.
The mini-exon gene: a molecular marker for Endotrypanum schaudinni
Authors: Fernandes O. , Degrave W. , Campbell D. A. 
Published: June 2009

SummaryThe mini-exon gene repeats from three different strains of Endotrypanum schaudinni have been amplified by the polymerase chain reaction (PCR). Sequence analysis of the cloned products shows the gene and intergenic region to be identical in two of the strains (LV86 and M6159); the intergenic region from the mini-exon gene of the third strain (LV59) is significantly different. The LV86 gene and an intergenic probe from the LV59 mini-exon gene do not cross-hybridize with the mini-exon gene from New World Leishmania species. These data provide the basis of a PCR assay to detect E. schaudinni and distinguish it from New World Leishmania species, and which should be applicable to epidemiological studies in insect vectors and mammalian reservoirs. The identification of two different mini-exon gene repeats in E. schaudinni isolates is indicative of further strain variation within this species.
Modelling toxoplasma incidence from longitudinal seroprevalence in Stockholm, Sweden
Authors: Nokes D. J. , Forsgren M. , Gille E. , Ljungström I. 
Published: June 2009

SummaryAge-stratified data on toxoplasma seroprevalence in pregnant women in Stockholm, Sweden for the years 1969, 1979 1987 provide the basis for an analysis of temporal patterns of Toxoplasma gondii infection, and estimation of the risk maternal toxoplasmosis, in this population. A catalytic infection model, in which the rate or force of infection is assumed to be a function of time (and not, as is more usual, age), was employed to describe the observed changes in levels toxoplasma seropositivity. A range of simple incidence functions (up to 3 parameters) were fitted using a method maximum likelihood. The data were significantly better described by a linear or an exponential decay in the rate of infection through time compared with a constant level. More complex incidence functions gave no better data description. Thus, whilst there is strong evidence for declining incidence in Stockholm over the past 4–5 decades, the data do not allow discrimination between different possibilities for the nature of this decline. Based on these modelling results, best estimates of the force of infection in 1987 acting on susceptible women are within the range 0 to 0·0045/susceptible/year (95% confidence limits), yielding a possible risk of maternal toxoplasmosis of between 0 and 2·7 cases/1000 pregnancies. These values are shown to be significantly lower than estimates based upon an assumption of temporal stability in toxoplasma incidence, which may be of practical significance to public health policy.
Experimental onchocerciasis in chimpanzees: cellular responses and antigen recognition after immunization and challenge withOnchocerca volvulusinfective third-stage larvae
Authors: Lüder C. G. K. , Soboslay P. T. , Prince A. M. , Greene B. M. , Lucius R. , Schulz-Key H. 
Published: June 2009

summaryImmunization of chimpanzees with radiation-attenuated infective 3rd-stage larvae (L3) ofOnchocerca volvulusdid not induce strong protective immunity against a subsequent challenge infection; only 1 out of 4 immunized animals remained non-patent (i.e. microfilariae-negative) after challenge, and may have been protected. However, during immunization and before challenge, a broad range of adultO. volvulus-derived antigens (OvAg) and also uterus-derived OvAg were recognized by circulating antibodies; moreover, the repertory of antigens recognized increased further in subsequently patent animals after challenge, particularly in the range ofMr12–42 kDa. In the immunized and non-patent chimpanzee, by contrast, serological recognition of uterus-derived OvAg withMr14 kDa and 105 kDa disappeared by 19 months post-challenge (p.c.). During immunization,Acanthocheilonema viteaeL3 antigens ofMr11–12 kDa were strongly recognized only by the non-patent animal, suggesting that recognition of these antigens may have supported resistance to the subsequent challenge infection. In immunized chimpanzees, a substantial increase in the cellular reactivity to OvAg was induced; this, however, declined by 19 months p.c. to levels similar to those seen prior to immunization. At that time, 3 out of 4 immunized animals were patently infected. The effect of exogenous cytokines onin vitro-reactivity of PBMC to OvAg was examined. Addition of exogenous IL-2 alone, IFN-γ alone, and IFN-γ in combination with IL-2, did not augment net cellular responses to OvAg by PBMC from infected and control chimpanzees. In the presence of IL-4 alone, IL-6 alone, IL-2 with IL-4, IL-2 with IL-4 and IFN-γ, or IL-2 with IL-4 and IL-6, the net cellular reactivity to OvAg increased significantly in patent chimpanzees and reached levels similar to non-patent animals. Thus, non-patent chimpanzees maintain high cellular reactivity to OvAg andin vitrocellular unresponsiveness to OvAg on the part of patent chimpanzees is reversible after addition of several cytokines which act individually or synergistically.
Gland cells and secretions in the miracidium of Fasciola hepatica
Authors: Wilson R. A. 
Published: June 2009

SUMMARYThe distribution and fine structure of gland cells in the miracidium of Fasciola hepatica is described. There is a large flask-shaped, multinucleate, apical gland lying ventrally in the anterior. On each side of this are pairs of uninucleate accessory gland cells. Both apical gland and accessory gland cells communicate with the tip of the apical papilla. A third group of vesiculated gland cells opens by ducts at the base of the apical papilla. The miracidium is covered with a surface mucous coat and this appears to be directly extruded from the underlying ciliated epithelial cells. The findings are discussed with relevance to attachment to, and penetration of, the snail intermediate host.
Eimeria species: studies using rRNA and rDNA probes
Authors: Ellis J. , Bumstead J. 
Published: June 2009

SUMMARYrRNA and a heterologous cloned rDNA probe have been used to detect the rRNA genes of Eimeria species which infe the chicken, and has allowed the isolation and preliminary characterization of cloned rDNA sequences from a genomic DNA library of Eimeria tenella. It is demonstrated that rRNA and rDNA probes can be used to identify individual Eimeria species by the restriction fragment patterns detected after Southern hybridization. In addition, studies have shown that the large and small subunit rRNAs are expressed throughout sporulation.
Speciation of echinostomes: evidence for the existence of two sympatric sibling species in the complex Echinoparyphium recurvatum (von Linstow 1873) (Digenea: Echinostomatidae)
Authors: McCarthy A. M. 
Published: June 2009

SUMMARYEvidence for the existence of 2 first intermediate host-specific sibling species of the 45 collar-spined echinostome Echinoparyphium recurvatum is presented. Experimental studies on their life-cycles were carried out under controlled laboratory conditions. The two entities were found to be morphologically indistinguishable in all major respects, yet they exhibited distinct biological characteristics. One of the sibling species utilizes the freshwater lymnaeid pulmonate snail Lymnaea peregra as first intermediate host, and the adults occur in the anterior small intestine of the wildfowl experimental definitive host Anas platyrhynchos. The other utilizes the freshwater mesogastropod prosobranch snail Valvata piscinalis as first intermediate host, and the adults occur in the posterior small intestine and rectum of A. platyrhynchos. The existence of the two sibling species in sympatry may be explained by the fact that the life-cycles of the two forms represent two distinct cycles of transmission serving to reduce excessive competition between them.
Seasonal variations in the parasite infections in a population of three-spined sticklebacks,Gasterosteus aculeatusL.
Authors: Pennycuick Linda 
Published: June 2009

A population of three-spined sticklebacks,Gasterosteus aculealus, from a pond in Somerset was sampled about every three weeks for 19 months, a total of 1863 fish being collected. Three species of parasites were found in the fish:Schistocephalus solidus,Diplostomum gasterosteiandEchinorhynchus clavula.Seasonal changes in the incidence and intensity of the three parasitic infections are described. In general the infections increased in summer and autumn and decreased in winter and spring, although inSchistocephalusthe differences in the level of infection between the two years were greater than between seasons.The largest increases in theSchistocephalusandEchinorhynchusinfections occurred in August and September and in theDiplostomuminfection in May and June. These increases could be related to the feeding activity of the sticklebacks and to the abundance and level of infection of theCyclops,AsellusandLimnaea peregerpopulations.Reduction in the sizes of the infections was by predation and death of heavily infected fish in the case ofSchistocephalusandDiplostomumand mainly by death of individual worms inEchinorhynchus.These mechanisms are shown to be adapted to the life cycles of the parasites.I am most grateful to Dr H. D. Crofton for his help and encouragement during this investigation and to Dr R. A. Avery for useful discussions and advice. This work was supported by a Science Research Council research studentship and a NATO studentship.
On the morphology, growth and identification of the pre-infective larvae of some horse strongylids
Authors: Ogbourne C. P. 
Published: June 2009

Descriptions are given of the first and second-stage larvae of Strongylus edentatus, S. vulgaris, S. equinus and Trichonema nassatum and newly hatched larvae of Trichonema catinatum and Triodontophorus serratus. Information has been obtained on the growth of pre-infective larvae and on the structural changes which occur during the first ecdysis. Most of the species of newly hatched larvae studied can be differentiated on the basis of differences in appearance, dimensions and other morphological features. The advantages of differential diagnosis of horse strongylid infection using first-stage larvae rather than infective larvae are discussed.My thanks are due to Dr H. D. Crofton for his constructive criticism and advice and to Professor H. E. Hinton, F.R.S. for the provision of laboratory facilities.This work would not have been possible without the willing co-operation of Mr L. J. Potter from whose slaughterhouse the parasites were collected. I am also indebted to the Horse Race Betting Levy Board for their financial assistance.
The pathological effects of sporocysts, rediae and metacercariae on the digestive gland of Bithynia tentaculata (Mollusca: Gastropoda)
Authors: Reader Trevor A. J. 
Published: June 2009

The uninfected digestive gland of Bithynia tentaculata consists of three main cell types: ‘absorptive’ cells, ‘thin’ cells and ‘secretory’ cells. With infection by sporocysts, rediae, or metacercaria, pressure effects caused a reduction in the lumen of the digestive gland tubules and this probably resulted in a starvation autolysis. Some tubules recovered from infection and in such cases there was a reduction in the height of the epithelium. A migration of the digestive gland nuclei was only evident in redial infections and this may have been due to the toxic effects of rediae. In addition, rediae directly ingested host digestive gland tissue.The digestive gland was reduced to about two-thirds of its normal size in all heavily infected snails. Secretory cells of the gland were more resistant to infection than were the absorptive or thin cells.I am indebted to Dr F. R. Stranack for her supervision and guidance throughout this investigation, and to Dr G. Charles and Dr T. Jenkins for their continued help and advice. This study was carried out during the tenure of a Research Assistantship awarded by the Governors of Portsmouth Polytechnic.
Trypanosoma (Megatrypanum) incertumfromPipistrellus pipistrellus: development and transmission by cimicid bugs
Authors: Gardner R. A. , Molyneux D. H. 
Published: June 2009

SUMMARYTrypanosoma (Megatrypanum) incertumPittaluga 1905 was found in 33 out of 206Pipistrellus pipistrelluscaught at various sites in Britain. The trypanosome is described from blood smears. Development took place in laboratory-rearedCimex pipistrelliandCimex lectularius. Epimastigote forms initially multiplied rapidly in the ventriculus and midgut ofCimex. Metacyclic trypanosomes were found in the rectum of both species ofCimexafter 8 days when bugs were maintained at 20 °C and as early as 3 days at 30 °C. Electron microscopy of infected bugs revealed that there was no attachment to epithelial cells of the ventriculus or midgut, but within the rectum epimastigotes were attached by their flagella to the cuticle of the rectum by hemidesmosomes. Transmission was achieved by feeding experimentally infected bugs to bats kept in the laboratory. These bats were negative as judged by xenodiagnosis using laboratory-rearedCimex. Bats which had been caught in the wild demonstrated low-grade or sub-patent parasitaemias (positive in xenodiagnosis) for up to 400 days after the day of capture. Despite an extensive search of impression smears of tissues immediately after trypanosomes first appeared in the blood of experimentally infected bats no multiplicative stages were found.