bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic structure of Anisakis physeteris, and its differentiation from the Anisakis simplex complex (Ascaridida: Anisakidae)
Authors: Mattiucci S. , Nascetti G. , Bullini L. , Orecchia P. , Paggi L. 
Published: June 2009

SUMMARYThe genetic structure of Anisakis physeteris from the Mediterranean Sea has been analysed electrophoretically at 22 enzyme loci. The samples studied, although differing in the life-stage (larvae and adults), and in the host (the fishes Micromesistius poutassou and Trachurus trachurus, and the sperm whale Physeter macrocephalus) were genetically homogeneous. Of these loci 11 (Ldh, Sod, Np, Adk-2, Pgm-1, Est-1, Est-2, Acph-1, Acph-2, Lap-2 and Ca) were found to be monomorphic, while the other 11 (Sdh, Mdh, ldh, 6-Pgdh, G3pdh, Got, Adk-1, Pgm-2, Lap-1, Mpi and Gpi) showed from 2 to 7 alleles. The following values of genetic variability were estimated: He = 0·ll, P = 0·50, A = 1·95. Distinct alleles were found between A. physeteris and the A. simplex complex at 19 out of the 22 loci studied, and only few rare alleles were shared at the remaining 3 loci. The genetic divergence between A. physeteris and A. simplex A and B is therefore very high, the values of Nei’s index D being 7·384 and 6·443 respectively (I = 0·001 and 0·002). The assignation of A. physeteris and the A. simplex complex to two distinct subgenera, Skrjabinisakis and Anisakis, as proposed by Mosgovoy on a morphological basis, appears to be fully justified according to our genetic data.
Antibody dependent cell-mediated cytotoxicity againstTrypanosoma cruzi
Authors: Abrahamsohn I. A. , Da Silva W. D. 
Published: June 2009

SummaryThis paper describesin vitroantibody dependent cytotoxicity againstTrypanosoma cruziepimastigotes by normal mouse splenic lymphocytes. Cytotoxicity was expressed as the percentage reduction in the number of motile parasites upon incubation with lymphocytes at 37 °C in a denned medium. Failure of the non-motile parasites to regain motility and their ensuring degeneration at 28 °C in liver infusion tryptose (LIT) medium confirmed loss of motility as a criterion of cytotoxicity. Incubation ofT.cruziat 37 °C for 18 h in a defined mediumper sedid not interfere with motility but was followed by a lag phase of the growth curve in LIT medium at 28 °C. The lag phase was prolonged forT. cruziwhich had previously been incubated at 37 °C in the absence of cells.
Stimulation of the activity ofSchistosoma mansonimiracidia by snail–conditioned water
Authors: Mason P. R. 
Published: June 2009

SummaryA dark-ground photographic technique was used to analyse the reactions ofSchistosoma mansonimiracidia to homogeneous solutions of snail–conditioned water (SCW). The most significant effect of this water was to increase miracidial turning. This effect was maintained under both acid and alkaline conditions, after passage of the SCW through a mixed bed resin and after chelation of either calcium or both calcium and magnesium ions. The stimulant in the water was unaffected by trypsin but was protease–sensitive, suggesting its possible identity as a peptide. The importance of ‘active spaces’ rather than concentration gradients in miracidial host–location was emphasized.
Freeze fracture studies on the interaction between the malaria parasite and the host erythrocyte inPlasmodium knowlesi infections
Authors: McLaren Diane J. , Bannister L. H. , Trigg P. I. , Butcher G. A. 
Published: June 2009

SUMMARYThe freeze fracture technique has been used to study the internal cyto-architecture of the surface membranes of the parasite and erythrocyte inPlasmodium knowlesiinfections. Six fracture faces, derived from the plasma membrane and 2 pellicular membranes, have been identified at the surface of the free merozoite. The apposed leaflets of the 2 pellicular membranes show the characteristic features of E fracture faces, a result compatible with the view that the pellicular membranes line a potential cisterna. There is evidence to suggest that there may be changes in the distribution and density of the integral proteins in the merozoite plasma membrane at invasion. Furthermore, vesicles consisting of stacked membranes occur within and around the erythrocyte invagination at invasion; it is suggested that these vesicles are released from the merozoite rhoptries. Formation of the parasitophorous vacuole is accompanied by dramatic changes in the density and distribution of intra-membraneous particles (IMP) in the vacuolar membrane. Initially there is a great reduction in particle numbers, but subsequently the particles reappear and show reversed polarity. The possible causes and implications of these changes are discussed. The intra-erythrocytic parasite synthesizes new transmembrane proteins as development proceeds, and the trophozoite and schizont stages of development are characterized by the appearance of circular, particle-free regions in the parasite plasmalemma. There is a decrease in the density of transmembrane proteins in the erythrocyte plasma membrane during parasite maturation, and the P face IMP show the characteristic features of aggregation.
Tegumental disruption with Triton X-100 and its effects on longitudinal muscle function in male Schistosoma mansoni
Authors: Depenbusch J. W. , Thompson D. P. , Pax R. A. , Bennett J. L. 
Published: June 2009

SUMMARYLongitudinal muscles in adult male Schistosoma mansoni appear to remain in almost all respects functional after tegumental disruption by Triton X-100. Responses to high K+, ouabain, low temperature, praziquantel and neurotransmitters are still present. Muscle membrane potentials remain near those of control animals and lanthanum nitrate is still excluded from the muscle after the Triton treatment. Although muscle contractility remains after tegumental disruption, sodium and calcium levels, as measured by plasma emission spectroscopy, increase by 20–30% while potassium and magnesium levels decrease by 15%. 45Ca2+ accumulation is double that of control animals. Upon exposure to a bathing medium lacking Ca2+, Triton-treated animals lose responsiveness to high K+, ouabain, low temperature and praziquantel more rapidly than do control animals. D-600, which effectively blocks the high K+ response in control animals, has no measurable effect on the high K+ response in Triton-treated animals, suggesting that voltage-dependent Ca2+ channels are present in the tegument.
Secondary infections of Hymenolepis diminuta in mice: effects of varying worm burdens in primary and secondary infections
Authors: Befus A. D. 
Published: June 2009

In one (1c) and six (6c) cysticercoid primary infections of Hymenolepis diminuta in NIH (inbred) and CFLP (outbred) male mice 6±1 weeks old > 85% of the worms established but were rejected (destrobilated or expelled) subsequently. Rejection occurs more quickly in 6c infections than in 1c infections. Considerable worm growth occurs in 1c and 6c primary infections but worms from 6c infections weighed less than worms from 1c infections on all days studied.Expulsion of H. diminuta does not occur more rapidly in secondary infections than in primary infections; loss of 6c secondary worms occurs at the same rate as 6c primary worms but 1c secondary worms survive longer than 1c primary worms. Although worms are not lost more quickly in secondary than in primary infections, they are affected at an early age by the immune response which stunts their growth. Increasing the intensity of primary and secondary infections increases the severity of stunting of secondary worms.The results are discussed and it is suggested that immune responses to Hymenolepis spp. in rodents are common but that thresholds of worm numbers exist below which appreciable worm loss does not occur. Stunting due to crowding, which generally is attributed to inter-worm competition, may be in part immunologically mediated. For future immunological studies attempting to induce secondary responses to H. diminuta in mice, worm growth, not survival, is the criterion to evaluate.
Effect of gamma-irradiation on oocysts of Eimeria necatrix
Authors: Singh Jasmer , Gill B. S. 
Published: June 2009

Effect of gamma radiation on oocysts of Eimeria necatrix was investigated. It was observed that oocysts exposed to 200 kR or above did not sporulate. Irradiation at 10–150 kR caused a progressive decrease in sporulation. Irradiation affected normal development of unsporulated oocysts as the zygote protoplasm divided into unequal masses or was shattered into granules.Increase in the intensity of irradiation of sporulated oocysts resulted in the progressive decrease in severity of the resultant infections in chicks and their effects – mortality, type of lesions developed, total oocyst production and immunity produced – were comparable with infections induced by decreasing the number of unirradiated oocysts. Infection produced by 1000 unirradiated oocysts was comparable with that resulting from 50000 oocysts irradiated at 25 kR. Infection obtained with 20000 unexposed oocysts approximated to that produced by 50000 ooeysts irradiated at 2·5 kR. It was concluded that irradiation abolished infectivity of the oocysts/sporozoites rather than bringing about attenuation of the parasite.
Separation of erythrocytes infected with murine malaria parasites in metrizamide gradients
Authors: Eugui Elsie M. , Allison A. C. 
Published: June 2009

SUMMARYDensity gradients with metrizamide, a tri-iodinated benzamido derivative of glucose, have been used to separate erythrocytes infected with 3 species of murine plasmodia. Good separations were obtained of uninfected erythrocytes from erythrocytes containing parasites in different developmental stages. With metrizamide solutions, the densities required for isopycnic separation can be obtained without hypertonicity or high viscosity, and the viability and those aspects of the metabolism of parasites and erythrocytes that we measured are not detectably modified by exposure to these solutions. This type of separation has many possible applications to biochemical and immunological investigations.
Brugia malayi microfilaraemia in mice: a model for the study of the host response to microfilariae
Authors: Grove D. I. , Davis R. S. , Warren K. S. 
Published: June 2009

SUMMARYMicrofilariae of Brugia malayi were obtained from the peritoneal cavities of infected gerbils and were then injected intravenously into mice. A sub-periodic, nocturnal microfilaraemia was produced. The level of microfilaraemia was proportional to the number of parasites injected, with approximately 1–3% of microfilariae being found in the peripheral circulation. The duration of microfilaraemia was proportional to the number of parasites injected; it subsided by 30 days after injection of 104 microfilariae but was still present at a low level 120 days after injection of 2 × 105 microfilariae. A transient splenomegaly developed after injection of microfilariae. Histopathological examination revealed large numbers of microfilariae free in the lumens of pulmonary small blood vessels and without any accompanying inflammatory reaction. Lesser numbers of microfilariae were seen in the cardiac blood and hepatic and renal blood vessels for the first few days after injection. There was cellular proliferation in the splenic white pulp and vascular congestion of the red pulp. Microfilariae labelled with 51Cr were injected intravenously; 57% of radioactivity was found in the lungs, 8·5% in the liver and 2·9% in the spleen. Mice developed immediate hypersensitivity reactions to B. malayi antigen by 4 weeks after injection, but Arthus and delayed hypersensitivity reactions were not seen at any time. When mice which had been injected 5 months previously were challenged with a 2nd injection of microfilariae, there was an accelerated clearance of parasites over 2 weeks and a marked peripheral blood eosinophilia developed. In contrast with natural infections, in which the continuous production of microfilariae complicates assessment, this model provides a system in which factors controlling the circulation of microfilariae in the bloodstream can be studied independently.
Processing of the precursor to the major merozoite surface antigens ofPlasmodium falciparum
Authors: Holder A. A. , Sandhu J. S. , Hillman Yvonne , Davey Lynne S. , Nicholls S. C. , Cooper Helen , Lockyer M. J. 
Published: June 2009

SUMMARYSpecific sequences derived from the gene for the precursor to the major merozoite surface antigens (PMMSA) ofPlasmodium falciparumhave been expressed inEscherichia coliand the products have been used to produce antibodies. These antibodies, together with monoclonal antibodies, have been used to investigate the form of the PMMSA protein associated with merozoites. Polypeptide fragments derived by processing from the PMMSA protein have been detected in extracts of merozoites and assigned to locations within the PMMSA coding sequence.
Inhibited development of Ostertagia ostertagi in relation to production systems for cattle
Authors: Smeal M. G. , Donald A. D. 
Published: June 2009

SUMMARYOn a coastal farm in New South Wales where beef and dairy cattle production was carried on side-by-side, separate pasture plots were contaminated with eggs of Ostertagia ostertagi by calves from each production system in autumn, winter or spring. Successive groups of parasite-free tracer calves grazed on the plots for 14 days at 4-week intervals and were then killed for worm counts 14 days after removal from pasture. On all plots, the proportion of inhibited early 4th-stage larvae in tracer calves reached a maximum in spring, and was consistently and very significantly higher in calves which grazed plots contaminated with O. ostertagi of beef cattle origin. Factors which may be responsible for this difference between beef and dairy cattle populations of O. ostertagi are discussed.
Microelectrode studies of the tegument and sub-tegumental compartments of maleSchistosoma mansoni: anatomical location of sources of electrical potentials
Authors: Bricker Connie S. , Pax R. A. , Bennett J. L. 
Published: June 2009

SUMMARYHistological studies using horse-radish peroxidase (HRP) as a marker, injected iontophoretically through a recording electrode, have indicated the origins of potentials encountered upon advancement of the electrode into and beneath the dorsal surface of adult maleSchistosoma mansoni. The first potential encountered, having a value of – 51 ± 0·6 mV originates across the outer tegumental membrane. The next potential has a value of — 28 ± 0·6 mV and originates in the muscle masses underlying the tegument. Finally, a potential having the value — 10 ± 0·5 mV originates within the basal lamina and the interstitial fibres and extracellular space surrounding the muscle. Altering ion concentrations in the bathing medium (i.e. high K+, low Na+, zero Ca2+, low Cl−, high Li+) depolarizes all three potentials. External applications of ouabain and the anti-schistosomal, praziquantel, also cause depolarization of the potentials. It appears that the muscle potential and the tegumental potential are primarily K+-dependent. The depolarizing effects of ouabain, LiCl and low Na+suggest that active transport is important in the maintenance of the muscle potential, just as is the case for the tegumental potential. There appears to be a close correlation between changes in the tegumental, muscle and extracellular space potentials. The correlation between tegument and muscle potential changes might be explained by junctional complexes between tegumental cell bodies and muscle cell bodies.
Microelectrode studies of the tegument and sub-tegumental compartments of male Schistosoma mansoni: an analysis of electrophysiological properties
Authors: Thompson D. P. , Pax R. A. , Bennett J. L. 
Published: June 2009

SUMMARYStandard intracellular microelectrode techniques were used to determine the electrical properties of the tegument and sub-tegumental regions in male Schistosoma mansoni. Three distinct compartments of electrical potential were observed. The resting potentials recorded in these compartments of –45·9±2·5 mV (Eteg), –22·0±1·1 mV (E2) and – 4·7±0·3 mV (E3) corroborate those previously reported by Fetterer, Pax & Bennett (1980) and Bricker, Pax & Bennett (1981). Input resistance was measured in each compartment and was found to be 4·5 MΩ (tegument), 9·2 MΩ (E2) and 3·5 MΩ (E3). Time-constants for the tegument, E2 and E3 were 0·24±0·01 msec, 0·25±0·01 msec and 0·13±0·01 msec, respectively. Multiple electrode experiments revealed that the tegument and E2 compartment are electrical syncytia with similar current-spreading capabilities. Low resistance pathways also appear to connect the tegument and E2 region, since electrotonic signals initiated in either of those compartments experience only a 15–25% reduction upon passing into the other. Injecting large (> 200 nA) depolarizing current pulses into the tegument or E2 compartment often resulted in the initiation of active membrane responses. These spikes were highly variable, ranging from 4 to 75 mV in magnitude (occasionally overshooting zero potential by as much as 25 mV) and from 10–40 msec in duration. The responses were not actively propagated along the parasite, and their decay over distance was approximately equal to that predicted on the basis of length constant values obtained from electrotonic signals. The addition of a non-diffusible solute to the recording medium resulted in a significant reduction in the current-spreading capacity of both the tegument and E2 compartment. Coupling ratios between the tegument and E2 compartment were decreased, and the input resistance for both compartments increased, while resting potentials remained constant. Active responses could not be evoked in schistosomes exposed to the hyperosmotic medium.
Thymus-independent crypt hyperplasia and villous atrophy in the small intestine of mice infected with the trematodeEchinostoma revolutum
Authors: Bindseil E. , Christensen N. Ø. 
Published: June 2009

SUMMARYConventional mice and congenitally athymic, nude mice were infected with 20 metacercariae of the intestinal trematodeEchinostoma revolutum. The sequential events in the pathological changes in the intestine were studied at different intervals post-infection. By day 11 onwards the conventional mice displayed dilatation of the region of the intestine which harboured the parasites. The mucosa in the dilated region showed marked crypt hyperplasia, villous atrophy and subepithelial fibrosis as the most conspicuous features which, together with a hypertrophy of the muscular layers, made the wall of the gut in the dilated region thicker than normal. The changes were thymus-independent as they were found to be as severe in the athymic, nude mice as in the conventional mice. The main histological features observed in the mice are discussed in relation to other conditions with similar changes, such as coeliac disease, nippostrongyliasis and trichinellosis. It is concluded that the present results support the view that there may be more than one effector mechanism of the change.
Degenerating exo-erythrocytic forms of Plasmodium berghei in rat liver: an ultrastructural and cytochemical study
Authors: Jap P. H. K. , Meis J. F. G. M. , Verhave J. P. , Meuwissen J. H. E. Th. 
Published: June 2009

SUMMARYMorphological and cytochemical aspects of the host response to almost mature exo-erythrocytic forms (EEF) of Plasmodium berghei in rat hepatocytes were studied by electron microscopy. Young stages (< 47 h) never evoked a local reaction. Two types of nearly mature EEF (47–51 h) could be distinguished, normal (EEF type I) and those that were the target of infiltrating cells (EEF type II). The latter were in a stage of early or advanced degeneration and generally exhibited increased electron density, especially in the contents of their peripheral vacuoles. Neither type of EEF exhibited detectable enzyme activity, although host cell enzymes, such as peroxidase and 5-nucleotidase, were demonstrable. However, the infected liver cell appeared permeable to ruthenium red whereas non-infected hepatocytes were not. When signs of degeneration were present, as shown by the increasing density of the cytoplasm, loss of enzyme activities occurred. The encompassing mononuclear cells were identified as true monocytes, non-monocyte-derived and monocyte-derived macrophages by their endogenous peroxidase activity. Macrophage filopodia penetrated and cleaved both hepatocyte and parasite cytoplasms. Subsequently, digestion and clearing of the remnants took place. This study clearly demonstrated that a proportion of the intra-hepatocytic EEF was destroyed by macrophages before they were able to mature completely and release their merozoites.
Naturally occurring agglutinins against trypanosomatid flagellates in the haemolymph of insects
Authors: Ingram G. A. , East Janet , Molyneux D. H. 
Published: June 2009

SUMMARYIn vitrostudies of the behaviour of the trypanosomatid flagellatesTrypanosoma bruceiandLeishmania hertigiin the presence of cell-free haemolymph of locusts,Schistocerca gregariaand cockroaches,Periplaneta americanarevealed the presence of parasite agglutinins. The range of normal values of agglutination titres was 2−4to 2−13. Physico-chemical treatment of haemolymph indicated that these agglutinins are protein or glycoprotein in nature and are only partially affected by heat treatment below 65°C, at which temperature incubation of haemolymph for 30 min abrogated all agglutination. Agglutination was not dependent on the presence of Ca2+or Mg2+. Prior infection of locusts and cockroaches withT. bruceiandL. hertigisignificantly increased agglutinin titres between Days 4 and 6 in cockroaches (P< 0·05) and from Days 2 to 4 whenL. hertigiwas inoculated into locusts. The induced differences in titres observed in locusts infected withT. bruceiwere not significant. Lysozyme levels were significantly increased after inoculation ofT. bruceiinto cockroaches compared with placebo-inoculated and uninoculated controls.L. hertigiinoculation produced significant increases in lysozyme levels compared with controls between Days 1 and 7 in locusts and 3 to 6 in cockroaches. These studies indicate that, at least in easily manipulated model systems, induced responses to intrahaemocoelic inoculation to trypanosomes andLeishmaniacan occur. As far as we are aware this is the first report of an induced response of an insect to such important parasites. The possibility that induced responses in natural vectors to these parasites occurs requires investigation.
A new technique for the extraction of Nematodirus battus eggs from sheep faeces
Authors: Coadwell W. J. , Martin Jean , Ward P. F. V. 
Published: June 2009

SUMMARYDetails are given of a method for the separation of the eggs of the nematode Nematodirus battus from sheep faeces. Faecal pellets obtained from worm-free lambs experimentally infected with N. battus were homogenized and passed through a graded series of metal sieves. The material retained in a 53, µm aperture sieve was transferred to a cylindrical column and the eggs were cleaned and separated from other suspended material by controlled differential flotation using tap water. A model experiment indicated that, within limits, the principle held for any size of tower. The density distribution for eggs at the morula stage of development was determined. Suggested flow rates for a specified tower are given.
Microgametogony of Sarcocystis hirsuta in the intestine of the cat
Authors: Dubey J. P. 
Published: June 2009

SUMMARYThe development of microgamonts was studied in the small intestine of a 2-day-old cat after oral inoculation with 107 bradyzoites of Sarcocystis hirsuta. The cat was given bradyzoites in 2 doses at 2 h apart and killed 4 h later. Gamonts were seen in parasitophorous vacuoles of goblet cells in the epithelium of the small intestine. All stages of microgametogony, from the single nucleated meront to fully developed gametes, were seen. Microgamonts measured 6·9 × 6·0 μm and macrogamonts measured 6·0 × 5·0 μm.