bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of lectin- and snail plasma-binding glycopeptides associated with the tegumental surface of the primary sporocysts ofSchistosoma mansoni
Authors: Johnston L. A. , Yoshino T. P. 
Published: June 2009

SUMMARYCarbohydrates associated with the tegumental surface ofSchistosoma mansoniprimary sporocyst may serve as potential receptors for mediating recognition by the internal defence system of the molluscan host,Biomphalaria glabrata. Therefore, a combination of SDS-PAGE and lectin probe analyses were carried out on biotin-labelled tegumental glycopeptides as a first step to defining the carbohydrates expressed at the sporocyst surface. The majority of surface polypeptides, ranging in relative molecular masses from 27 to 113 kDa, reacted with horseradish peroxidase-labelledCanavalia ensiformis(Con A),Erythrina corallodendron(ECA),Glycine max(SBA) andTriticum vulgaris(WGA) lectins indicating that most, if not all, tegumental proteins are glycosylated. However, differences in the binding of some lectins to individual glycopeptides suggest a degree of heterogeneity in the structure/composition of sugar moieties comprising these surface glycoconjugates. This notion is supported by the finding that the fucose-specificTetragonolobus purpureas(TPA) lectin only reacted with approximately 50% of glycopeptides identified at the tegumental surface. Experiments employing biotin-labelled plasma (cell-free haemolymph) fromS. mansoni-susceptible and -resistantB. glabratasnails as probes, further demonstrated that many of the identified surface glycoproteins also serve as plasma-binding sites for both snail strains. Binding interactions between plasma and sporocyst surface glycoproteins appeared to be, at least in part, mediated by carbohydrates since periodate treatment of sporocyst proteins or pre-incubation of plasma with the glycoproteins, fetuin or mucin, resulted in a decrease in plasma reactivity to blotted larval proteins.
The impact of variations in temperature on early Plasmodium falciparum development in Anopheles stephensi
Authors: Noden B. H. , Kent M. D. , Beier J. C. 
Published: June 2009

SUMMARYThe effect of temperature on early Plasmodium falciparum development was examined in Anopheles stephensi. The rates of both ookinete development and bloodmeal digestion were lengthened as temperatures decreased from 27 to 21 °. However, low temperatures (21–27 °) did not significantly influence infection rates or densities of either ookinetes or oocysts. In contrast, high temperatures (30 and 32 °) significantly impacted parasite densities and infection rates by interfering with developmental processes occurring between parasite fertilization and ookinete formation, especially during zygote and early ookinete maturation. This study demonstrates clearly that temperature affects the sporogonic development of P. falciparum in anophelines by altering the kinetics of ookinete maturation. These studies not only confirm the ookinete as the key development stage affecting the probability of vector infectivity, they provide new insights into the epidemiology of P. falciparum infections.
The blood-stages of Plasmodium georgesi, P. gonderi and P. petersi: course of untreated infection in their natural hosts and additional morphological distinctive features
Authors: Poirriez J. , Dei-Cas E. , Dujardin L. , Landau I. 
Published: June 2009

SUMMARYIn the blood of a Cercocebus albigena and of a C. galeritus agilis monkey, the infection with Plasmodium gonderi was found to follow its well-known chronic course; P. georgesi seemed to occur as a relapsing type of malaria parasite; P. petersi was found for only a few days and at a low level in C. albigena (end of an attack?). As shown by using polarized light, the pigment granules appeared mostly as fine dots in P. georgesi, short rods in P. gonderi and long needles in P. petersi. The three species can be distinguished by the morphological appearance of the nucleus of the young trophozoites, and also by the measurement of its surface area (Sa): small round nucleus (Sa= 0·81 ± 0·06 μm2) in P. gonderi, large 2-coloured nucleus (Sa= 1·43 ± 0·21 μm2) in P. petersi, and long crescent-shaped nucleus (Sa= 2·18±0·25 μm2) in P. georgesi. The first colour illustrations of the blood-stages of P. georgesi are presented. The dynamics of single and mixed blood infections in primate malaria parasites are discussed, with a proposal to classify them into 3 types.
Plasmodium yoelii nigeriensis: the effect of high and low intensity of infection upon the egg production and bloodmeal size of Anopheles stephensi during three gonotrophic cycles
Authors: Hogg J. C. , Hurd H. 
Published: June 2009

SUMMARYAnopheles stephensi mosquitoes showed a reduction in fecundity over 3 successive gonotrophic cycles, after becoming infected with Plasmodium yoelii nigeriensis. This effect could be observed at high oocyst burdens (> 75) or at low oocyst burdens (mean of 4·36). Mean bloodmeal size of the infected mosquitoes was significantly reduced only when feeding upon a mouse with a high gametocytaemia and the conversion of the bloodmeal into eggs by the infected mosquitoes was disrupted. Patterns of infected mosquito mortality, over the 3 gonotrophic cycles, varied with severity of infection. Although in 1 case increased mortality and decreased bloodmeal size may have affected fecundity, this could not have accounted for all of the observed fecundity reduction. We propose that other, unknown parasite related factors, are involved.
Identification and properties of a neuropeptide-degrading endopeptidase (neprilysin) ofAscaris suummuscle
Authors: Sajid M. , Isaac R. E. 
Published: June 2009

SUMMARYWe have previously identified in membranes of the locomotory muscle ofAscaris suuma phosphoramidon-sensitive endopeptidase which hydrolyses the neuropeptide AF1 (Lys-Asn-Glu-Phe-Ile-Arg-Phe-NH2) by cleavage of the Glu3-Phe4bond (Sajid & Isaac, 1994). We have determined the properties of this neuropeptide-degrading enzyme ofA. suummuscle using AKH-I (ρGlu-Leu-Asn-Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH2) and [D-Ala2, Leu5]enkephalin as convenient endopeptidase substrates. Phosphoramidon, thiorphan and SQ 28603, potent inhibitors of mammalian neprilysin (neutral endopeptidase, endopeptidase 24.11), inhibited the endopeptidase activity towards AKH-I with IC50values of 0·13 μM, 22 μM and 6·3 μM, respectively. Two other neprilysin inhibitors (SCH 32615 and SCH 39370) and the bivalent metal ion chelators, EDTA (1 mM) and 1, 10bis-phenanthroline (1 mM) failed to inhibit the nematode enzyme. The endopeptidase had a neutral pH optimum and a significant proportion (45%)of the enzyme activity partitioned into the detergent-rich phase of Triton X-114, indicating that the enzyme is an integral membrane protein. The muscle enzyme also attacked [D-Ala2, Leu5]enkephalin cleaving the Gly3-Phe4bond and this hydrolytic activity was inhibited by phosphoramidon and thiorphan (IC50, 0·28 ρM and 15·8 ρM, respectively) but not by EDTA and 1,10bis-phenanthroline. The phosphoramidon-sensitive endopeptidase activity was detected on intact muscle cells prepared by collagenase treatment of the body wall musculature, indicating that endopeptidase is accessible to peptide molecules that interact with the cell surface.
A modified binomial model that describes the infection dynamics of the entomopathogenic nematode Steinernema feltiae (Steinernematidae; Nematoda)
Authors: Hay D. B. , Fenlon J. S. 
Published: June 2009

SUMMARYThird-stage (dauer) juveniles of the entomopathogenic nematode Steinernema feltiae from 3 laboratory populations were tested for infectivity to larvae of the sciarid fly Lycoriellia solani. Bioassay experiments were done to assess the effects of nematode application density, exposure time and host density on the proportion of individuals that established infection. When dauer stages were presented to a host singly, establishment rates of 28, 26 and 18% were obtained for the 3 populations, but the presence of conspecifics consistently increased the rate of establishment to 42, 33 and 21% respectively, at 20 nematodes per host. A modified binomial model was developed to show that nematode establishment was not related to application density in a linear fashion, as initial infection facilitated secondary colonization. The data suggest that 3 subpopulations of nematodes may be distinguished by their infection behaviour: a first group of individuals with the behavioural propensity to initiate infection in unparasitized insects, a second that only invaded infected hosts, and a third group of non-invaders that failed to establish in L. solani.
Mode of nutrition of the larvae of the filarial nematode Brugia pahangi
Authors: Beckett Evelyn B. , Boothroyd B. 
Published: June 2009

SUMMARY(1) Light-microscopic observations were made on B. pahangi larvae at various stages of development in stained serial sections of A. aegypti thoraces, and on 8-to 9-day 2nd-stage live, unstained larvae.(2) Six-day larvae situated in A. aegypti flight muscle, and isolated 8- to 9-day 2nd-stage larvae, were examined with the electron microscope.(3) Results showed that host-muscle mitochondria which appeared to be morphologically intact aggregated outside the larvae at the head and tail ends and were present from 6 days onwards in the oesophagus and in the midgut. Those in the oesophagus were unchanged; some of those in the midgut were intact, others showed varying degrees of disintegration suggestive of digestion. Host-muscle mitochondria are therefore likely to be a source of nutrients for B. pahangi larvae during the last third of their intramuscular developmental phase.Dr W. W. Macdonald, of the Liverpool School of Tropical Medicine, kindly supplied the infected mosquitoes, and offered valuable advice in the course of this work. Miss M. A. Johnson assisted with the care of the mosquitoes.We are particularly indebted to Mr David John for his patient work in preparing the filariae for electron-microscopic observation. Mrs J. Oliver assisted with some of the histological preparations.We are pleased to acknowledge the financial assistance of the Royal Society towards the purchase of the ultramicrotomes used in the course of this work.
Larvae of the Ixodes ricinus complex of species
Authors: Snow Keith R. , Arthur Don. R. 
Published: June 2009

SUMMARYAn account is given of the morphological characteristics of larvae of four species of the Ixodes ricinus complex, namely I. ricinus, I. persulcatus, I. pacificus and I. nipponensis. Particular reference is made to chaetotaxy and its importance in differentiating larvae of closely related species is emphasized.We are grateful to Dr G. Owen Evans for discussion on matters on chaetotaxy.
The quantity of blood imbibed by Hyalomma anatolicum anatolicum Koch, 1844 (Ixodoidea, Ixodidae)
Authors: Snow Keith R. 
Published: June 2009

1. The weight of blood ingested by all stages of H. anatolicum anatolicum has been determined and from the results a direct relationship appears to exist between the weights of replete adults and their blood content. In engorged nymphs the relationship was subject to some variations, while in fully fed larvae no such correlation was apparent, indicating the ingestion of a large proportion of extravascular fluids.2. It was found that all instars concentrate the imbibed blood by the elimination of water. In larvae the concentration is by a factor of at least 5·25, in nymphs 3·4, in females 2·1 and in males 1·4.3. A correlation was found between the external colour of fully engorged larvae and the quantity of blood imbibed.I wish to thank Dr R. P. Chaudhuri for providing the original specimens of H. anatolicum anatolicum from which the culture was started, and Professor Don. R. Arthur for reading the manuscript and for his advice and assistance.
Extended schizogony of Eimeria mivati in betamethasone-treated chickens
Authors: Long P. L. , Rose M. Elaine 
Published: June 2009

Cortisone treatment of BL chickens given oocysts of Eimeria mivati resulted in the production of greater numbers of oocysts in the faeces and a prolonged patent period.Schizonts were seen in sections of the intestines of treated birds up to the 24th day after oocyst inoculation although none was seen in control chickens after the 8th day. These late schizonts resembled those of the 3rd and 4th generations recorded for this species but may be those of a generation not yet described.The depletion of intestinal lymphoid tissue in cortisone-treated birds is noted. The findings are discussed with reference to host-parasite relationships.We wish to thank the scientific assistants and senior poultry attendant of the department for their help throughout the work.
Description of a model to simulate effects of Eimeria acervulina infection on broiler production
Authors: Henken A. M. , Graat E. A. M. , Ploeger H. W. , Carpenter T. E. 
Published: June 2009

SummaryA simulation model for effects of Eimeria acervulina infection on technical and economic characteristics in broiler production is presented. The model describes development over time of the growth depression, feed intake reduction, and decrease in feed efficiency associated with infection. The model also shows a phase of compensatory growth during which earlier negative effects are counterbalanced, at least partly. Major assumptions made were: infection with E. acervulina occurs in each flock; production is affected in each flock; compensatory growth takes place because immunity develops and cell regeneration occurs. The results show that the pattern of development of the production characteristics during a flock cycle depends on the initial contamination level. Both a high and low initial contamination level results in a lower average daily gain, a worse feed to gain ratio, and a reduced net revenue compared to an intermediate contamination level.
Purification and biochemical characterization of acetylcholinesterase (AChE) from the excretory/secretory products ofTrichostrongylus colubriformis
Authors: Griffiths G. , Pritchard D. I. 
Published: June 2009

SummaryAcetylcholinesterase (AChE) has been purified from the excretory/secretory (ES) products ofTrichostrongylus colubriformis(using edrophonium chloride linked to epoxy-activated Sepharose) with yields of 40–50%. Purity was confirmed by polyacrylamide gel electrophoresis (using silver [protein] and Karnovsky [activity] stains) and measurement of specific AChE activity. Further analysis of the purified fractions by gel filtration and sucrose density gradient techniques revealed the existence of 2 forms of hydrophilic AChE (Mr189 and 80 kDa). From the data we deduce these to be the globular monomer and dimer, G1 and G2 forms of AChE. Inhibition studies using BW284C51, iso-OMPA and excess substrate, along with substrate specificity studies, show both forms to be true acetylcholinesterases. We are currently assessing the protective immunogenicity of purified AChE in sheep.
Spermiogenesis and spermatozoan ultrastructure inPolymorphus minutus(Acanthocephala)
Authors: Whitfield P. J. 
Published: June 2009

The spermiogenesis and spermatozoan morphology of the palaeacanthocephalan,P. minutuswere studied by a variety of electron microscopical methods.Spermiogenesis occurs in syncytial clusters of spermatids exhibiting synchronous development. The outstanding events of the spermiogenic process are an enormous elongation of the spermatid nucleus and the eventual breakdown of the spermatid nuclear envelope.The mature spermatozoon is a filiform cell about 60 μm long and motile by propagated undulations. It consists of two parallel elongate components, the single flagellum and the spermatozoan body. The former has a 9 + 2 tubule organization and the latter contains glycogen granules and membrane-bound dense inclusions as well as a region of condensed chromatin of nuclear origin. No mitochondria appear to be present.In the University of Cambridge I should like to thank Professor H. Goodwin for the provision of electron microscope facilities and Mr B. Chapman for teaching me to use them. At King's College, London I am indebted to Professor D. R. Arthur and Professor F. R. Whatley for facilities and Mr H. Edge for excellent technical assistance. The work reported in this paper was initiated during the tenure of an S.R.C. Research Studentship and completed whilst in receipt of a Research Fellowship from the Nuffield Foundation.
Characterization of membrane proteins exported from Plasmodium falciparum into the host erythrocyte
Authors: Johnson D. , Günther K. , Ansorge I. , Benting J. , Kent A. , Bannister L. , Ridley R. , Lingelbach K. 
Published: June 2009

SUMMARYPlasmodium falciparum is an intracellular parasite of the red blood cell. During development it exports proteins which are transported to specific locations within the host erythrocyte. We have begun to identify and characterize exported membrane proteins of P.falciparum in order to obtain specific marker molecules for the study of the mechanisms involved in the distribution of parasite-derived proteins within the host cell. In this report we describe the characterization of a 35 kDa protein which is recognized by a monoclonal antibody. The protein is tightly associated with membranes isolated from infected erythrocytes; it is resistant to extraction with alkali and soluble after treatment with detergents. It is located at the membrane of the parasitophorous vacuole and in membrane-bound compartments which appear in the cytoplasm of the infected erythrocyte. The protein co-localizes with the previously described exported protein-1 (exp-1). Considering its localization and physical similarities to exp-1, we name the 35 kDa protein the exported protein-2 (exp-2).
Haemoglobin inhibits the development of infective promastigotes and chitinase secretion inLeishmania majorcultures
Authors: Schlein Y. , Jacobson R. L. 
Published: June 2009

SUMMARYHaemoglobin or blood in the growth medium ofLeishmania majorinhibited the formation of infective promastigotes and the secretion of chitinases. Inoculation of mice with stationary-phase parasites from control medium caused infections in 20/29 mice, compared to 3/20 mice injected with parasites grown with 10% rabbit blood, or 1/30 mice that received parasites grown with rabbit haemoglobin. The concentration of peanut lectin (PNA) required to agglutinate promastigotes was used as an index of their infectivity, ranging from a high concentration for infective populations to a low concentration for relatively non-infective populations. Agglutination of 50% of the parasites from control medium or from medium containing rabbit haemoglobin required 4·1 μg PNA/ml and 0·1 μg PNA/ml, respectively. Chitinase activities/107parasites decreased from 4·8 units chitinase and 12·5 unitsN-acetylglucosaminidase (NAGase) in the control to 2·0 units chitinase and 8·5 units NAGase in cultures containing rabbit haemoglobin. Rabbit, human, bovine and pigeon haemoglobins had various inhibitory effects on the activity of chitinases and not on the virulence, as expressed by PNA agglutination. The relevance of the results to the cycle ofLeishmaniais discussed.
FMRFamide-related peptides (FaRPs) in nematodes: occurrence and neuromuscular physiology
Authors: Maule A. G. , Bowman J. W. , Thompson D. P. , Marks N. J. , Friedman A. R. , Geary T. G. 
Published: June 2009

SUMMARYThe occurrence of classical neurotransmitter molecules and numerous peptidic messenger molecules in nematode nervous systems indicate that although structurally simple, nematode nervous systems are chemically complex. Thus far, studies on one nematode neuropeptide family, namely the FMRFamide-related peptides (FaRPs), have revealed an unexpected variety of neuropeptide structures in both free-living and parasitic species. To date 23 nematode FaRPs have been structurally characterized including 12 from Ascaris suum, 8 from Caenorhabditis elegans, 5 from Panagrellus redivivus and 1 from Haemonchus contortus. Ten FaRP-encoding genes have been identified in Caenorhabditis elegans. However, the full complement of nematode neuronal messengers has yet to be described and unidentified nematode FaRPs await detection. Preliminary characterization of the actions of nematode neuropeptides on the somatic musculature and neurones of A. suum has revealed that these peptidic messengers have potent and complex effects. Identified complexities include the biphasic effects of KNEFIRFamide/KHEYLRFamide (AF1/2; relaxation of tone followed by oscillatory contractile activity) and KPNFIRFamide (PF4; rapid relaxation of tone followed by an increase in tone), the diverse actions of KSAYMRFamide (AF8 or PF3; relaxes dorsal muscles and contracts ventral muscles) and the apparent coupling of the relaxatory effects of SDPNFLRFamide/SADPNFLRFamide (PF1/PF2) to nitric oxide release. Indeed, all of the nematode FaRPs which have been tested on somatic muscle strips of A. suum have actions which are clearly physiologically distinguishable. Although we are a very long way from understanding how the actions of these peptides are co-ordinated, not only with those of each other but also with those of the classical transmitter molecules, to control nematode behaviour, their abundance coupled with their diversity of structure and function indicates a hitherto unidentified sophistication to nematode neuromuscular intergration.
Molecular cloning andin vitroexpression ofC. elegansand parasitic nematode ionotropic receptors
Authors: Fleming J. T. , Baylis H. A. , Sattelle D. B. , Lewis J. A. 
Published: June 2009

SUMMARYThe free living nematode,C. elegansis understood at a level of detail equalled by few other organisms, and much of the cell biology and sequence information is proving of considerable utility in the study of parasitic nematodes. Already,C. elegansprovides a convenient vehicle for investigating anthelmintic drug action and resistance mechanisms. Among the ionotropic receptors, with their important roles in the behaviour and development of the organism, are targets for anthelmintics. The subunits of nicotinic acetylcholine receptors ofC. elegansform a large and diverse multigene family. Members of this family are among the 11 genes associated with resistance to the anthelmintic drug levamisole.
Resistance toEimeriainfections in the chicken: the effects of thymectomy, bursectomy, whole body irradiation and cortisone treatment
Authors: Rose M. Elaine , Long P. L. 
Published: June 2009

SUMMARYSurgical bursectomy or thymectomy at day old had little effect on primary or subsequent infections withE. brunetti or E. maxima.Whole body irradiation of day-old chickens with 700 or 750 R did not affect the development of immunity to theseEimeriaspp., but in some experiments it affected oocyst production during initial infections.In one of four trials, birds surgically bursectomized and irradiated produced twice as manyE. brunettioocysts during an initial infection as the irradiated only controls; in the remaining three trials, oocyst production in the operated birds was either similar to or slightly greater than that in the controls. Combined bursectomy and irradiation did not affect immunity to re-infection.Combined thymectomy and irradiation had little effect on primary infections (increased oocyst output was found in only one of six trials) and no effect on subsequent immunity; mean body weights and circulating lymphocyte numbers were decreased but tuberculin sensitivity was reduced in only a small proportion of the birds, indicating that the cell mediated immune responses of the majority were not affected.Small (0.75 mg) daily doses of cortisone acetate given to irradiated birds or irradiated thymectomized birds, did not affect resistance to reinfection withE. brunetti.We wish to thank Dr B. M. Freeman for surgical bursectomy; Mr E. A. King, Department of Radiotherapeutics, University of Cambridge, for irradiation and members of the technical staff of the Parasitology Department for their willing and skilled assistance.