bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in the structure of the male reproductive system of Nematodirus battus during its rejection from lambs
Authors: Martin Jean , Lee D. L. 
Published: June 2009

SUMMARYAs the infection progresses in lambs, the developing germ cells of male Nematodirus battus become filled with lysosome-like bodies, electron-dense granules and membrane-bound vesicles, and the organization and division of the gametic nucleus appears to be altered. The epithelial cells of the reproductive tract are also damaged and the secretory-type globules produced by the cells of the vas deferens are denatured. These changes are compared with ultrastructural changes observed in other species of nematode affected by the immune response of their hosts.
Infectivity of cultured Plasmodium falciparum gametocytes to mosquitoes
Authors: Ponnudurai T. , Lensen A. H. W. , Van Gemert G. J. A. , Bensink M. P. E. , Bolmer M. , Meuwissen J. H. E.TH. 
Published: June 2009

SUMMARYVarious factors that may influence routine and high levels of mosquito infection with cultured Plasmodium falciparum gametocytes are considered in this paper. One of the most important is the choice of an appropriate isolate, with facilities for cryopreservation and a good technique for initiation of cultures. The use of automated culture systems with strict adherence to detail and routine has eliminated much of the variability. The quality of the serum used for the culture of gametocytes and inclusion in the feed material for mosquitoes is of the highest importance. Blood collection for culture purposes must preferably involve alcohol as an antiseptic for cleaning donor skin or suitable receptacles. Mosquito blood meals should not include plasma with citrate phosphate dextrose or sera collected in microtainer tubes or from volunteers on proguanil-chloroquine prophylaxis. Sera of individuals on chloroquine alone do not influence transmission. Haemato-crits of from 5 to 10% permit the culture of equally infective gametocytes. It was impossible to predict the outcome of an infection in mosquitoes based on the number of female gametocytes or gametes. Within any experiment, the oocyst load initially increased, followed by a decline with progressively lower numbers of gametocytes accompanied by a progressive increase in the efficiency of transmission. Some of the variability of mosquito infection within an experiment was due to individual differences in the speed of blood digestion of the mosquitoes. A new membrane feeder is described with three different sizes to accommodate a variety of goals. The new design permitted more mosquitoes to feed within a limited period compared to the older more widely used feeder of equivalent capacity, and mosquitoes feeding on the new-type feeder were frequently better infected than those fed on the older type.
The anticoccidial effects of amprolium, dinitolmide and monensin against Eimeria maxima, E. brunetti and E. acervulina with particular reference to oocyst sporulation
Authors: Joyner L. P. , Norton C. C. 
Published: June 2009

Chicks infected with the Weybridge strains of Eimeria maxima and E. acervulina were not protected by the normal levels of amprolium, but the sporulation of the oocysts was inhibited. With higher drug concentrations, fewer oocysts were produced. E. brunetti was not so markedly affected, although oocyst sporulation was reduced by the higher dosage levels. The effects were not enhanced by the inclusion of ethopabate.With dinitolmide the phenomenon was not so marked, although oocyats of E. maxima and E. acervulina were reduced in numbers by the normal drug concentration and sporulation was reduced when this level was increased. Much higher drug levels were required to obtain these effects with E. brunetti. Monensin at 120 ppm affected neither oocyst numbers nor their sporulation in any of the species tested. The significance of the effects of anticoccidial drugs on gametogony and sporogony is discussed.
Asymmetric reproductive output by the monogenean Pseudodiplorchis americanus
Authors: Tocque K. , Tinsley R. C. 
Published: June 2009

SUMMARYPseudodiplorchis americanus accumulates its entire reproductive output in utero during hibernation of its host, Scaphiopus couchii. Infective larvae are released only during the toads' brief entry into water for breeding. In one host population studied prior to transmission, in S.E. Arizona, adult worms contained 0–326 infective stages; 19% of 178 worms produced 51% of the total larvae. Reproductive output was positively correlated with body length which was considered to reflect worm age; first-, second- and third-year worms produced means of 5, 43 and 96 larvae, respectively. Within second- and third-year cohorts, there was a density-dependent reduction in offspring numbers. Under controlled laboratory conditions, the mean rate of offspring accumulation during the first 6 months of development was significantly reduced only in burdens in excess of those found naturally (36–68 worms). In older parasites, a density-dependent reduction in the mean accumulation rate occurred in burdens of 20–32 worms, where 88% of parasites produced offspring at less than half the maximum rate. The asymmetry in individual reproductive output increased with competition and there were significant reductions in the median rates of offspring accumulation at smaller burdens (17–25 and 5–14 worms, in experimental and natural infections, respectively) than evident from decreases in the mean. Thus, individual variation is a more sensitive measure of competition than is the mean.
Effect of the sulphydryl reagent, mersalyl acid, on sex pheromone reception by Heterodera schachtii (Nematoda: Heteroderidae) males
Authors: Aumann J. 
Published: June 2009

SUMMARYFemale sex pheromone reception was inhibited in a bioassay by treating males of the beet cyst nematode, Heterodera schachtii, with the sulphydryl reagent, mersalyl acid. This effect was blocked by the sulphydryl group protectant, dithiothreitol, indicating the occurrence of sulphydryl groups in the receptor molecules and a role for sulphydryl groups in pheromone reception.
Ultrastrucural observations on the interactionin vitrobetween bovine eosinophils and juvenileFasciola hepatica
Authors: Glauert Audrey M. , Lammas D. A. , Duffus W. P. H. 
Published: June 2009

SUMMARYThis ultrastructural study has shown that there is a layer of dense flocculent material on the surface of juvenileFasciola hepaticaincubatedin vitrowith specific bovine antiserum. This material corresponds to the complexes of secreted glycocalyx and bovine antibody previously characterized by fluorescence microscopy. Bovine eosinophils attach closely to those regions of the parasite's surface that are free of flocculent precipitates. This close attachment is followed by degranulation of the eosinophils into the narrow zone between the cells and the parasite. Only in these regions is damage, in the form of vacuolation of the tegument, seen within the juvenileF. hepatica. It is concluded that the inability of bovine eosinophils to kill juvenileF. hepaticain the presence of specific antiserum results from the presence of a protective layer, consisting of antigen/antibody complexes, on the parasite's surface.
Pyrolysis gas-liquid chromatography of the pathotypes of the potato cyst nematodesGlobodera rostochiensisandG. pallida
Authors: Fox P. C. , Atkinson H. J. 
Published: June 2009

SUMMARYCurie-point pyrolysis gas-liquid chromatography (PGLC) was used to detect gross chemical differences between the 8 European pathotypes of the potato cyst nematodesGlobodera rostochiensisandG. pallida. No qualitative differences were seen with either flame ionization or flame photometric detection systems, although quantitative differences between pathotypes were detected. Cluster analysis of these differences failed to group the pathotypes into species, but separation of some economically important pathotypes was achieved. The potential of PGLC for nematode identification is discussed.
Observations on the development of the male reproductive system in Gyrodactylus gasterostei Gläser, 1974 (Monogenea, Gyrodactylidae)
Authors: Harris P. D. 
Published: June 2009

SUMMARYThe development of the male reproductive system in Gyrodactylus gasterostei has been followed using parasites of known age maintained on isolated hosts. The penis develops shortly after the parasite has given birth for the first time (at an age of 24–30 h at 13°C) and the first active spermatozoa appear after 40–50 h. Spermatogenesis occurs more rapidly in G. gasterostei than in any other parasitic flatworm (including those from warm-blooded hosts) in which it has been measured, and the onset of male maturity is further hastened by a reduction in the number of pre-spermatogenic germ cell divisions. Spermatogonia have a diploid chromosome complement of 12, and spermatocytes undergo meiosis to produce haploid spermatozoa. No evidence of aneuploidy in spermatozoa was obtained. Although the development of haploid spermatozoa suggests that sexual reproduction can occur, production of embryos by isolated flukes which lack a mature male system indicates that other means of reproduction may also be employed.
The survival of parasite eggs throughout the soil profile
Authors: Storey G. W. , Phillips R. A. 
Published: June 2009

SUMMARYAn experiment using lysimeters suggested that the eggs ofTaenia saginataandAscaris lumbricoidessurvive for only a short time when applied to pasture in sewage sludge. However, a subsequent experiment which followed the survival of eggs throughout the soil profile demonstrated that someT. saginataeggs could still be found at 200 days on the soil surface, and that survival increased down the profile. Rainfall is shown to be able to wash eggs into the soil where they may be afforded protection from radiation and desiccation; this may have little epidemiological significance.
Observations on the morphology of the testis in the larvae ofMoniliformis(Acanthocephala)
Authors: Asaolu S. O. 
Published: June 2009

SUMMARYTestes in the male early acanthella ofMoniliformis dubiusare cellular. The testes in the middle and late acanthellae and cystacanth stage also contain individual cells but these are embedded in a compact supporting syncytium which also forms the boundary of the testis. The testes are embedded in the cytoplasmic wall of the ligament sac in the early acanthella but after this stage they become exposed in the cavity of the sac when the surfaces of the testes become covered by a surface coat. Certain cells adjacent to testes primordia in the early acanthella appeared to have formed rudiments of vasa efferentia in the middle acanthella.
Hierarchical order of host cues in parasite foraging strategies
Authors: Lewis E. E. , Grewal P. S. , Gaugler R. 
Published: June 2009

SUMMARYThe importance of host cues to three species of steinernematid nematodes (Rhabdita: Steinernematidae) with different foraging strategies was compared. We presented host materials to nematodes in series to test responses to combinations of host cues. If a fixed hierarchy of cues is followed during foraging, parasites should respond most strongly to cues offered in natural order. Steinernema carpocapsae, an ambush forager, aggregated at the source of volatile host cues only after attachment to host cuticle. They also parasitized hosts more efficiently after contact with cuticle. Steinernema glaseri, a cruise forager, was unaffected by exposure to combinations of host cues. Steinernema feltiae, a nematode with characteristics of both ambushing and cruising, was affected by cue hierarchies when either contact or volatile cues were presented first. Host-associated materials encountered out of the context may not qualify as host cues for the ambush forager, S. carpocapsae. Perhaps the order in which cues are encountered is more predictable for ambushers than for cruisers. Therefore an ambusher's response to host materials has a more fixed contextual framework.
External monitoring of 203Hg-labelled Dirofilaria immitis microfilariae in mice and dogs
Authors: Lengemann F. W. , Grieve R. B. , Chmielewicz M. , Kallfelz F. A. , Georgi J. R. 
Published: June 2009

SUMMARYMicrofilariae of Dirofliaria immitis were labelled with 203Hg 2+in vitro and injected into irradiated mice and Beagle dogs. With irradiated mice it was possible to demonstrate microfilariae present in the blood and to detect 203Hg by external counting as long as 28 days after dosing. The 203Hg 2+ label had a half-time of 4–5 days; the amount of stable mercury in the labelling medium strongly influenced the survival of microfilariae in vivo. In dogs, external counting showed the lungs to be a major location of the microfilariae soon after reinjection into the host. Evidence was obtained that labelled microfilariae can circulate; however, the detection of dispersed microfilariae is difficult because of the relative insensitivity of the detecting system. For radiomercury the accumulation of the inorganic form in the liver and kidneys limits the long-term usefulness of 203Hg 2+ as a label if the organism being studied also accumulates in these organs.
Generation and characterization of clonedTheileria parvaparasites
Authors: Morzaria S. P. , Dolan T. T. , Norval R. A. I. , Bishop R. P. , Spooner P. R. 
Published: June 2009

SUMMARYA 3-step procedure for cloningTheileria parvaparasites was developed. The first step involved thein vitroinfection of a fixed number of bovine lymphocytes with titrated sporozoites. The cell lines obtained from infections initiated using sporozoite/lymphocyte ratios below 1:100 were then selected for cloning as these contained schizont-infected cells, each of which was derived from infection with a single sporozoite. In the second step, these cell lines were cloned by limiting dilution. As sporozoites infect lymphocytes and transform to induce clonal multiplication, this step produced infected cell lines containing both cloned parasites and cloned lymphocytes. In the third step, the cloned cell lines were used to infect cattle and isolation of the parasite in ticks was made during piroplasm parasitaemia. Finally, sporozoites were harvested from infected ticks and used for further characterization. Sporozoites derived from cloned cell lines ofT. parvaMuguga, Marikebuni, Boleni, Uganda and buffalo-derived 7014 were characterized using monoclonal antibody profiles, DNA restriction fragment length polymorphism detected using repetitive and telomeric probes,in vivoinfectivity and, in one case, cross-immunity studies. Additionally, several distinct schizont-infected lymphocyte clones were isolated from the Muguga, Mariakani and buffalo-derived 7014 stocks. The combined results of the characterization revealed that the cloning procedure selected clones ofT. parvafrom the parental stocks which were known to contain a mixture of genetically different parasite populations. The cloning method and the clones generated will be of value in studies of the biology of the parasite and in elucidating the strain specificity of immune responses in cattle.
Random amplified polymorphic DNA fingerprints of the eight taxa of Trichinella and their comparison with allozyme analysis
Authors: Bandi C. , la Rosa G. , Bardin M. G. , Damiani G. , Comincini S. , Tasciotti L. , Pozio E. 
Published: June 2009

SUMMARYEight taxa have recently been proposed as being encompassed by the genus Trichinella on the basis of allozyme and biological data. In this paper we show that an analogous 8 taxon structure for this genus results from the random amplified polymorphic DNAs (RAPDs). Five 10-mer or 20-mer primers were used under different polymerase chain reaction (PCR) conditions to produce multiband RAPD fingerprints from muscle larvae of 40 isolates of Trichinella spp. The resulting RAPD data were analysed following the numerical taxonomic approach, and the resulting classification was compared to that derived from allozyme data. The agreement found between allozymes and RAPDs, while supporting the polyspecific structure of the genus Trichinella, confirms the potential of RAPDs as a tool for the detection of cryptic species. The selected primers were tested on individual muscle larvae in an attempt to standardize a RAPD assay for the routine identification of the 8 taxa of Trichinella. Only 1 of the 5 primers yielded reproducible fingerprints from the single larvae. Using this primer, the 5 species and the 3 other taxa of the genus Trichinella can be identified in a single assay without the need for massive in vivo parasite production.
Metabolism bySchistosoma mansoniof a new schistosomicide: 2-[(1-methylpropyl)amino]-1-octanethiosulphuric acid
Authors: Penido M. L. O. , Nelson D. L. , Vieira L. Q. , Watson D. G. , Kusel J. R. 
Published: June 2009

SUMMARYIn order to investigate the mode of action of a new class of schistosomicides, theN-alkylaminoalkanethiosulphuric acids, the ‘outer35S] 2-[(1-methylpropyl)amino]-1-octanethiosulphuric acid was synthesized. Labelling studies of adultSchistosoma mansoniwere performed in infected mice and inin vitroincubations. After a single oral dose of the drug to infected mice, 5 metabolites were detected by thin-layer chromatography in organic extracts of male and female adult schistosomes.In vitrostudies showed that the same compounds were present in organic extracts obtained from adult male and female worms. One of these metabolites was identified by mass spectroscopy as being the dimeric disulphide derivative of the parent labelled thiosulphuric acid.
Molecular genetic analysis ofGiardia intestinalisisolates at the glutamate dehydrogenase locus
Authors: Monis P. T. , Mayrhofer G. , Andrews R. H. , Homan W. L. , Limper L. , Ey P. L. 
Published: June 2009

SUMMARYSamples of DNA from a panel ofGiardiaisolated from humans and animals in Europe and shown previously to consist of 2 major genotypes–‘Polish’ and ‘Belgian’–have been compared with human-derived Australian isolates chosen to represent distinct genotypes (genetic groups I–IV) defined previously by allozymic analysis. Homologous 0·52 kilobase (kb) segments of 2 trophozoite surface protein genes (tsa417 and tsp11, both present in isolates belonging to genetic groups I and II) and a 1·2 kb segment of the glutamate dehydrogenase (gdh) gene were amplified by the polymerase chain reaction (PCR) and examined for restriction fragment length polymorphisms (RFLPs). Of 21 ‘Polish’ isolates that were tested, all yieldedtsa417-like andtsp11-like PCR products that are characteristic of genetic groups I or II (15 and 6 isolates respectively) in a distinct assemblage ofG. intestinalisfrom Australia (Assemblage A). Conversely, most of the 19 ‘Belgian’ isolates resembled a second assemblage of genotypes defined in Australia (Assemblage B) which contains genetic groups III and IV. RFLP analysis ofgdhamplification products showed also that ‘Polish’ isolates-were equivalent to Australian Assemblage A isolates (this analysis does not distinguish between genetic groups I and II) and that ‘Belgian’ isolates were equivalent to Australian AssemblageB isolates. Comparison of nucleotide sequences determined for a 690 base-pair portion of thegdhPCR products revealed ≥ 99·0% identity between group I and group II (Assemblage A/‘Polish’) genotypes, 88·3–89·7% identity between Assemblage A and Assemblage B genotypes, and ≥ 98·4% identity between various Assemblage B/‘Belgian’ genotypes. The results confirm that theG. duodenalisisolates examined in this study (inclusive ofG. intestinalisfrom humans) can be divided into 2 major genetic clusters: Assemblage A (= ‘Polish’ genotype) containing allozymically defined groups I and II, and Assemblage B (= ‘Belgian’ genotype) containing allozymically defined groups III and IV and other related genotypes.
Protective immunity toSchistosoma mansoniinduced in the olive baboonPapio anubisby the irradiated cercaria vaccine
Authors: Yole D. S. , Pemberton R. , Reid G. D. F. , Wilson R. A. 
Published: June 2009

SUMMARYThe radiation-attenuated schistosome vaccine induces a high level of protective immunity in rodents. In order to assess its potential relevance to man, we have tested its efficacy in the non-human primatePapio anubis. A vaccination regime consisting of 3 exposures of approximately 9000 cercariae irradiated with 30 or 60krad. of gamma radiation induced > 50% protection to a challenge with normal larvae. A lower attenuating dose of 20 krad., optimal for vaccination of mice, was less effective. All vaccination regimes elicited a population of PBMC which proliferatedin vitroin response to antigen. These responses peaked after the third exposure but were significantly lower after challenge. They revealed relatively little cross-reactivity with adultSchistosoma haematobiumantigens and provided some evidence for stage-specific antigens. Circulating IgM reactive with adultS. mansoniantigen was detected after the second vaccination but levels remained low throughout. In contrast, IgG levels were boosted by successive vaccinations, although they showed a tendency to decline from 14 days after each exposure. There also appeared to be a lag of about 14 days after challenge before levels began to rise. Thus, both proliferation and antibody data suggest a lower responsiveness after challenge which may reflect either the reduced antigenic load or immunogenicity of normal, compared to vaccinating larvae. The data indicate that the attenuated schistosome vaccine is capable of inducing protection in a highly permissive primate host, with the implication that the mechanisms involved may also be relevant to man.
A vasoactive intestinal polypeptide-like protein excreted/secreted byNippostrongylus brasiliensisand its effect on contraction of uninfected rat intestine
Authors: Foster N. , Lee D. L. 
Published: June 2009

SUMMARYThe 50–30 kDa fraction isolated from the excretory/secretory products (E/S) of the nematodeNippostrongylus brasiliensissignificantly decreased the amplitude of contraction of segments of uninfected rat intestine when injected into the lumen of the segments maintained in an organ bath. Dot blot analysis of the fraction suggested that it was similar in immuno-reactivity to porcine vasoactive intestinal polypeptide (VIP). When antiserum to porcine VIP was mixed withN. brasiliensisE/S and the mixtures were injected into the lumen of segments of rat intestine, the inhibitory effect of the E/S on amplitude of contraction decreased. When physiological concentrations of porcine VIP (12·9 pmol/ml) were injected into the lumen of segments of uninfected rat intestine the amplitude of contraction decreased significantly. Western blot analysis of the E/S, using antiserum to porcine VIP, recognized a 30 kDa protein in the E/S and also in whole worm homogenate suggesting that synthesis of the peptide occurs inside the nematode. Peptide histidine isoleucine (PHI)-like immuno-reactivity was detected in a 68 kDa fraction of the E/S and the homogenate but this fraction did not affect the amplitude of contractions of the intestine.
Investigations on the presence of an infectious proportion amongst populations ofSteinernema feltiae(Site 76 strain) infective stages
Authors: Bohan D. A. , Hominick W. M. 
Published: June 2009

SUMMARYExperimental studies were conducted on the proportion ofSteinernema feltiaeFilipjev (Site 76 strain) infective stages that infectedGalleria mellonellaL larvae, in sand tube assays. A full statistical analysis of the sand assay tubes was also undertaken. The analysis showed that the sand tubes were not a significant source of variation. Consequently the observed behaviour of the infective stages was considered to be due to a biological effect. The study shows that the proportion of infective stages that became parasitic did not increase with increases in the density of applied infective stages, nor did the proportion increase with an increase in the number of hosts. It is argued that these findings are consistent with the presence of a proportion of individual infective stages that are capable of causing infection.