bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coproantigen detection for immunodiagnosis of echinococcosis and taeniasis in dogs and humans
Authors: Allan J. C. , Craig P. S. , Garcia Noval J. , Mencos F. , Liu D. , Wang Y. , Wen H. , Zhou P. , Stringer R. , Rogan M. , Zeyhle E. 
Published: June 2009

SUMMARYThree ELISA assays, based on hyperimmune rabbit serum raised against adult cestode somatic antigen, were applied in this study for the detection ofTaenia- andEchinococcus-specific antigens in host faeces. The first assay, using an antiserum againstTaenia pisiformisantigen extract, was used in a time-course ofT. pisiformisexperimental infection in dogs. The assay was shown to be considerably more sensitive than microscopical detection of eggs in faeces. Antigen was present in faeces before patency and antigen levels were independent ofT. pisiformisegg output. The second assay, involving a test for human taeniasis based on antibodies againstT. solium, was applied in two field studies carried out in China and Guatemala. The test was highly specific, no false positive reactions occurred with human faecal samples and the test was capable of diagnosing individuals who would not have been detected by coproscopy or treatment to recover the tapeworm. A third assay was designed forE. granulosusand demonstrated 87·5% sensitivity and 96·5% specificity with samples from naturally and experimentally infected dogs withEchinococcusorTaeniainfections. In both the humanTaeniaand canineEchinococcusstudies antigen could be detected in faecal samples from infected hosts stored in 5% formalin for 6 months. Further refinements to these tests for field application are discussed.
Evaluation of a monoclonal antibody-based competition ELISA for the diagnosis of human hydatidosis
Authors: Liu D. , Lightowlers M. W. , Rickard M. D. 
Published: June 2009

SUMMARYAn antibody competition enzyme-linked immunosorbent assay (ELISA) using 4 different monoclonal antibodies (MAb) raised against major antigens (Antigen 5 and Antigen B) of Echinococcus granulosus was evaluated for the diagnosis of human hydatidosis. The competition assay, using anti-Ag5 MAb 24.14, detected specific antibodies in 70% (131/188) of sera from patients with surgically confirmed E. granulosus infection and 38·5% (10/26) of sera from patients with E. multilocularis infection. None of the sera from patients with Taenia solium cysticercosis (10), T. saginata (2), filariasis (22), strongyloidiasis (19), fascioliasis (4), bilharziasis (4) and amoebiasis (2) tested were positive using a cut-off point established through reaction between MAb 24.14 and normal human sera. The combined use of the MAb 24.14-based competition ELISA with the conventional antibody-binding assay provides a highly sensitive (92·8%) and specific screening system for human hydatid disease diagnosis.
Radiorespirometric detection of macrofilaricidal activityin vitro
Authors: Comley J. C. W. , Rees M. J. 
Published: June 2009

SUMMARYAnin vitromethod for studying radiorespiration has been adapted to single macrofilariae. Using this method viable (but not heat-killed)Dipetalonema viteaeandOnchocera gibsonimacrofilariae evolved measurable amounts of14CO2from L-[U-14C]glutamine. Nonlinear and less uniform rates of14CO2evolution were demonstrated with D-[U-14C]glucose, [1-14C]acetate and [1-14C]octanoate. These findings led us to develop anin vitroscreen in which inhibition of14CO2evolution from L-[U-14C]glutamine was used as a parameter for gauging macrofilaricidal activity. Using this screen we have examined the activity of 17 ‘so-called’ antifilarial standards and found a greater degree of sensitivity than shown by other biochemical criteria. Other data obtained suggest a role for radiorespirometry in determining the viability of fragments ofOnchocerca tissue.
Fluctuations in rat liver alanine-amino-transferase activity during experimental nippostrongylosis
Authors: Robertson Lucy J. 
Published: June 2009

SUMMARYThe activity of the gluconeogenic enzyme, alanine-amino-transferase (ALT), in a preparation from the liver of rats was studied by means of anin vitroassay throughout the course of a primary infection ofNippostrongylus brasiliensis, established by a subcutaneous injection of approximately 4000 3rd-stage larvae. The activity was measured on days 1–14 p.i. in both uninfected and infected rats and a marked pattern in the enzyme's activity was observed. In infected rats, the activity increased from 1·46±0·19 U/g liver on day 1 p.i. to a peak on day 4 p.i. of 10·75±1·62 U/g liver, then decreased to a trough of 0·44±0·18 U/g liver on day 10 p.i. before returning to original levels by day 14 p.i., by which time the infection had been largely eliminated. In uninfected rats the activity of the liver enzyme remained constant throughout this period with a value of 2·54±0·12 U/g liver. The activity of the enzymein vitrowas found to be related to the size of the inoculum on days 4 and 10 p.i. It was proposed that these observations could be due to either (1) a direct effect of the parasite, or (2) a consequence of the host immune response to the infection. In order to investigate the second proposition more fully, liver ALT activity was investigated byin vitroassay on selected days p.i. in rats experiencing a secondaryN. brasiliensisinfection. In these rats the liver ALT activity was observed to reach a peak on day 2 p.i., with an activity of 3·87 ± 0-28 U/g liver, and a trough on day 4 p.i. with an activity of 0·11 ±0·03 U/g liver, returning to similar levels to those measured in uninfected rats by day 7 p.i. When serum prepared from rats having secondaryN. brasiliensisinfections collected on day 4 p.i. was added to the assay, a reduction in the activity of liver ALT activity from both the infected and uninfected rats was measured byin vitroassay. The results are discussed in relation to protein metabolism and gluconeogenesis in rats infected withN. brasiliensis, and also in relation to the host’s immune response to the parasitic infection.
Giardiainfection in pigs: detection andin vitroisolation of trophozoites of theGiardia intestinalisgroup
Authors: Koudela B. , Nohýnková E. , Vítovec J. , Pakandl M. , Kulda J. 
Published: June 2009

SUMMARYGiardiainfections were detected in 14 out of 32 weaned, 1 to 2-month-old pigs, used in experiments with coccidia.Giardiatrophozoites were present in the small intestine from the duodenum to the ileum with maximum numbers in the cranial part of the upper jejunum. They were localized mainly on the surface of intestinal crypts. No histological changes accompanied the infection and the infected animals were asymptomatic.Giardiatrophozoites obtained from the intestines of necropsied pigs were isolated in axenic culture in a bile-supplemented TYI-S-33 medium. Morphological features of the trophozoites revealed by both light and scanning electron microscopy proved that the organism belongs to theGiardia intestinalisgroup.
The enigmatic presence of all gluconeogenic enzymes inSchistosoma mansoniadults
Authors: Tielens A. G. M. , Van Der Meer P. , Van Den Heuvel J. M. , Van Den Bergh S. G. 
Published: June 2009

SUMMARYThe activities of glucose-6-phosphatase (G6Pase), frucrose-1,6-bisphosphatase (FBPase), phosphoenolpyruvate carboxykinase (PEPCK) and pyruvate carboxylase (PC) were determined in homogenates of adultSchistosoma mansoniworms and compared with the activities in homogenates of rat liver and rat skeletal muscle, tissues with a high and a low gluconeogenic capacity, respectively. All four gluconeogenic enzymes were present inS. mansoni. The enzymes were less active than in rat liver, but the activities of G6Pase, PEPCK and PC were at least an order of magnitude higher than in rat skeletal muscle whereas FBPase was approximately equally active inS. mansoniand in rat muscle. Experiments with14C-labelled substrates or [14C]NaHCO3failed to demonstrate the actual occurrence of gluconeogenesis inS. mansoni. Some possible other functions of the gluconeogenic enzymes were investigated. Experiments with inhibitors of PEPCK gave no indications that this enzyme was involved in the degradation of glucose. This was confirmed by13C-NMR experiments which indicated that lactate was formed from phosphoenolpyruvate via the actions of pyruvate kinase and lactate dehydrogenase, and that PEPCK did not participate in the formation of lactate. Substrate cycling between fructose-6-phosphate and fructose-1,6-bisphosphate was demonstrated to occur in adultS. mansoni. This shows that FBPase participates in the glucose metabolism of this parasite.
Opisthorchis viverrini: relationships between egg counts, worms recovered and antibody levels within an endemic community in Northeast Thailand
Authors: Elkins D. B. , Sithithaworn P. , Haswell-Elkins M. , Kaewkes S. , Awacharagan P. , Wongratanacheewin S. 
Published: June 2009

SUMMARYThree techniques for estimating the intensity of Opisthorchis viverrini infection in individuals from a Northeast That community are compared. Egg counts were determined using a quantitative formalin/ethyl acetate technique, worm burdens were estimated by expulsion chemotherapy and antibody levels were measured by ELISA. Log-transformed worm and egg counts were closely correlated (r = 0·80), suggesting that both measurements provide good assessments of relative intensity of infection. However, no Opisthorchis worms were recovered from 34 people with high egg counts; probably due to problems with the expulsion technique in some individuals. Examination of egg production per fluke indicated that each fluke contributed an average of 180 eggs per gram (epg) of faeces and fecundity was negatively associated with total worm burden. Serum IgG levels correlated significantly with Opisthorchis egg count (r = 0·61) at two independent assessments. Although significant associations were observed between antibody levels and echinostome infection, analysis suggested that these reflected independent associations between these two variables and Opisthorchis infection and age. We conclude that all three measurements are useful for epidemiological studies.
Studies on the invasion ofNotocotylus attenuates(Notocotylidae: Digenea) into its snail host,Lymnaea peregra. In vitroobservations on the hatching mechanism of the egg
Authors: Murrills R. J. , Reader T. A. J. , Southgate V. R. 
Published: June 2009

SUMMARYMedia are described which stimulate the eggs ofNotocotylus attenuatusto hatchin vitro. Hatching involves opening of the operculum and emergence of the opercular cord to form a tube measuring approximately 75 μm in length along which the sporocyst passes. The sporocyst is then released from the end of the tube. It is suggested thatin vivothe opercular cord serves to inject the sporocyst through the snail host's gut wall into the haemocoel.
Host—parasite relationships ofBlastocrithidia familiarisinLygaeus pandurusScop. (Hemiptera: Lygaeidae)
Authors: Tieszen K. L. , Molyneux D. H. , Abdel-Hafez S. K. 
Published: June 2009

SUMMARYBlastocrithidia familiariswere found to be parasitic in the midgut, ileum and rectum ofLygaeus pandurus. The host—parasite relationship is described. Attachment of parasites in the midgut and ileum occurs by interdigitation of expanded flagella over and between the microvilli. No attachment to microvilli was observed where extracellular membranes form well-organized layers which lie parallel to the gut wall and completely separate the microvilli border from the lumen. The extracellular membranes originate from delamination of the outer unit membrane of microvilli which consists of a double plasma membrane. The function of the extracellular membrane layers and their possible role as a peritrophic membrane in preventing parasite attachment is discussed in relation to previous studies on midgut cells in Hemiptera with a similar apical coat on midgut microvilli. In the rectum, parasites attach to the cuticle of the gland cells and not to the rest of the rectal wall. Attachment to the cuticle occurs by the formation of hemidesmosomes. A comparison of the relationship ofB. familiarisand its host to previous ultrastructural studies of associations between kinetoplastid flagellates and their respective hosts is discussed.
Three dimensional structure of the leishmania amastigote as revealed by computer-aided reconstruction from serial sections
Authors: Coombs G. H. , Tetley L. , Moss V. A. , Vickerman K. 
Published: June 2009

SUMMARYComputer-aided reconstruction from serial sections has been used to analyse the 3-dimensional structure of entire amastigotes of Leishmania mexicana mexicana and to determine the number, arrangement and volume of each organelle. In two reconstructions, the lysosome-like ‘megasomes’ were the most numerous organelle, there being 34 in one amastigote, and they comprised as much as 15% of the total cell volume. In contrast, as few as 9 glycosomes were present, accounting for less than 1% of the cell volume. The unitary nature of the mitochondrion was confirmed and its complex basket-like structure was revealed. The spatial arrangement of the cell organelles is here displayed in stereo-pairs.
The use of DNA hybridization and numerical taxonomy in determining relationships between Trypanosoma brucei stocks and subspecies
Authors: Paindavoine P. , Pays E. , Laurent M. , Geltmeyer Y. , Le Ray D. , Mehlitz D. , Steinert M. 
Published: June 2009

SUMMARYThe nuclear DNAs of 71 trypanosome stocks from different African countries, representative of the three Trypanosoma brucei subspecies, and one T. evansi stock, have been analysed by the combined use of restriction endonuclease digestion, gel electrophoresis and molecular hybridization with both trypanosome surface-antigen-specific and undefined genomic DNA probes. In contrast with T. brucei brucei and T. brucei rhodesiense stocks, all the T. b. gambiense stocks are characterized by a conserved, specific DNA band pattern, regardless of the probe. This allows T. b. gambiense to be non-ambiguously identified. On the contrary, T. b. brucei and T. b. rhodesiense, which could not be discriminated by the same criteria, both yield highly variable DNA band patterns. Our data confirm that domestic animals like pig, dog and sheep constitute a potential reservoir for T. b. gambiense. Using a numerical analysis of the DNA hybridization patterns we have measured the degree of similarity between the 72 trypanosome stocks. This investigation shows that all T. b. gambiense stocks are included in the same homogeneous population, while the stocks from the two other subspecies seem to be distributed in several heterogeneous groups, some of these showing correlation with the geographical origin of the trypanosomes. It is concluded that (i) T. b. gambiense stands out as a real subspecies that has undergone a distinct evolution relative to the ‘non-gambiense’ group, (ii) the alleged T. b. rhodesiense subspecies does not fit with any of the groups evidenced by our cladistic analysis and hence does not appear as a distinct subspecies and (iii) ‘non-gambiense’ trypanosomes are probably evolving much more rapidly than T. b. gambiense. Different aspects of trypanosome relationships and evolution are discussed.
Echinococcus granulosus: absorption of cycloleucine and α-aminoisobutyric acid by protoscoleces
Authors: Jeffs S. A. , Arme C. 
Published: June 2009

SUMMARYProtoscoleces ofEchinococcus granulosusabsorb the amino acids cycloleucine and α-aminoisobutyric acid (AIB) by a combination of mediated uptake and diffusion. After correcting for the latter, values forKtandVmaxof 0·124 mM and 0·947 nmoles/mg protein/2 min for cycloleucine were calculated; corresponding values for AIB were 0·039 mM and 0·139 nmoles/mg protein/2 min. Both amino acids were accumulated against a concentration gradient and a comparison ofKtandKtvalues determined in mutual inhibition experiments suggested that both cycloleucine and AIB share a common uptake locus (loci). Cycloleucine uptake was pH-dependent and could be inhibited by a variety of other amino acids. Neither D- nor L-proline inhibited cycloleucine absorption but D-methionine, D-alanine, D-leucine, D-valine and D-serine were much more effective inhibitors than their L-counterparts.
Cloning and functional expression of a Shaker-related voltage-gated potassium channel gene from Schistosoma mansoni (Trematoda: Digenea)
Authors: Kim E. , Day T. A. , Bennett J. L. , Pax R. A. 
Published: June 2009

SUMMARYWe have isolated a cDNA (SKvl. 1) encoding a Shaker-related K+ channel from an adult cDNA library of the human parasitic trematode Schistosoma mansoni. The deduced amino acid sequence (512 aa, 56·5 kDa) contains 6 putative membrane-spanning domains (S1–S6) and a pore-forming domain (H5). SKv1.1 is grouped in the Shaker family, but forms a unique branch within this family, on the basis of dendrogram analysis. SKv1.1 shows significant sequence identity with most other Shaker channels, with 64—74% identity in the core region (S1–S6). It has the highest sequence identity with the K+ channel (Ak01a) from Aplysia. Northern blot analysis detected a single primary transcript of 2·8 kb. Southern blot analysis indicated that SKv1.1 is present as a single copy in the genomic DNA of S. mansoni. Expression of SKv1. 1 in Xenopus oocytes produced a rapidly activating and inactivating outward K+ current which is highly sensitive to 4-aminopyridine, but is insensitive to tetraethylammonium, mast cell degranulating peptide, dendrotoxin and charybdo-toxin. The presence of a Shaker homologue in Schistosoma suggests that Sh subfamilies may exist in other lower invertebrates as well as platyhelminths.
Acetyicholinesterase secretion–a parameter for the interpretation of in vitro anthelmintic screens
Authors: Rapson E. B. , Chilwan A. S. , Jenkins D. C. 
Published: June 2009

SUMMARYInterpretation of anthelmintic activity using in vitro screens has, until now, relied on the detection of drug-induced effects on nematode development, viability and motility. A novel biochemical parameter dependent upon the spectrophotometric assay of acetyicholinesterase (AChE), an enzyme secreted in large quantities by certain trichostrongylid nematodes, has been developed to replace these often subjective indices of activity. Using Nippostrongylus brasiliensis, a worm frequently employed for primary screening, the secretion of this enzyme in the presence or absence of a large number of drugs in vitro was determined. During a 4-day incubation period in a complex undefined medium without serum, AChE was secreted by normal 4th larval and immature adult stages of the worm in a linear fashion. All modern broad-spectrum veterinary anthelmintics, regardless of their mode of action, dramatically reduced the amount of enzyme secreted. Correlation between the biochemical and observa tional parameters was excellent and the selectivity of the assay when based solely on enzyme secretion was not lost. Other advantages were that the time required for the activity of certain slow-acting compounds to be detected was reduced from 7 to 4 days and that close microscopical examination of the worms was not necessary.
The development and mortality of the non-infective free-living stages of Ostertagia ostertagi in the field and in laboratory culture
Authors: Smith G. , Grenfell B. T. , Anderson R. M. 
Published: June 2009

SUMMARYA deterministic model of the population biology of the non-infective free-living phase of Ostertagia ostertagi is described and tested. A comparison of field and laboratory studies indicates that the pre-infective larvae of O. ostertagi spend about twice as long in this phase in the field as in laboratory culture (13 days and 7 days respectively at 15 °C), and that the subsequent transition (i.e. second moult) to the infective phase also proceeds at a much slower rate (about 10 times less at 15 °C) in the field. Because of this discrepancy, estimates of model parameters are based entirely on measurements from field studies. A two-parameter model of pre-infective development in the field is derived. It describes egg and larval development as a direct non-linear function of air temperature. We also show that the mortality of the eggs and pre.infective larvae increases with temperature (although this relationship probably also subsumes a dependence on faecal moisture content). The model is shown to be a good mimic of the population dynamics of the non-infective free-living phase when tested against an independent data set, and is the basis of a larger model of the epidemiology of ostertagiasis.
Oxantel-activated single channel currents in the muscle membrane ofAscaris suum
Authors: Dale V. M. E. , Martin R. J. 
Published: June 2009

SUMMARYThe patch clamp technique was used to investigate the action of the anthelmintic drug, oxantel, on nicotinic acetylcholine receptor (nAChR) currents recorded from vesicles of the somatic muscle cells of the nematode parasiteAscaris suum. The amplitudes of the currents were analysed at different membrane potentials to determine the single channel conductance. Also the open and closed durations were measured to determine the kinetic properties of the activated channel. Oxantel activated single nAChR currents throughout a concentration range 10–100 μM, these currents were not observed with oxantel-free pipette solutions. The mean open time of the activated channels at a membrane potential of –75 mV and a concentration of 10 μM was 1·34 ms. At higher concentrations the open times were shorter and voltage sensitive, decreasing in duration on hyperpolarization, thus suggesting open channel block. The kinetics were analysed using a simple channel block model. The forward block rate,K + B, increased with increasing oxantel concentration but showed little increase as the membrane was hyperpolarized.K + Bwas 2·41×107M−1s−1– 50 mV and 2·64 × 107M−1s−1at – 100mV. The unblocking rate constant,K – B, did exhibit voltage sensitivity being 443·6 s−1at – 50 mV and 86·8 s−1at –100 mV. Thus the blocking dissociation constantKB (= K – B/K + B)was 18·5 μM at –50 mV and 3·3 μM at –100 mV. The simple channel block scheme was found to be insufficient to explain fully the observations made; reasons for this are discussed.
Molecular phylogenetics of the four Schistosoma species groups determined with partial 28S ribosomal RNA gene sequences
Authors: Littlewood D. T. J. , Johnston D. A. 
Published: June 2009

SUMMARYPartial 28S ribosomal RNA (rRNA) gene sequences, including the variable domains D1, D2 and D3, were determined for representative species from the 4 Schistosoma species groups. On an alignment of 1345 bp from S. mansoni, S. haematobium, S. spindale and S. japonicum (with Heterobilharzia americana chosen as an outgroup), both maximum likelihood and maximum parsimony analyses provide a robust molecular phytogeny for the genus; ((((S. haematobium, S. spindale), S. mansoni), S. japonicum), H. americana). When analysed separately, both domain D1 and domain D2 yielded similarly informative data whereas D3 failed to resolve the phylogeny. These results confirm a phylogeny previously suggested by 18S rRNA gene sequences, corroborating the status of S. spindale as a sister taxon to S. haematobium, and demonstrate the utility of 28S rRNA gene sequence data for resolving phylogenies within the Schistosomatidae.Note: nucleotide sequence data reported in this paper are available in the EMBL database under the accession numbers Z46503/04/05/06/21.