bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunization against schistosome infection in rhesus monkeys with living worms by intraperitoneal injection
Authors: Hsü S. Y. , Hsü H. F. 
Published: June 2009

Immunization was performed against Schistosoma mansoni or S. japonicum infection in rhesus monkeys either with living schistosomula and young adult worms or with only schistosomula by intra-peritoneal injection. Each monkey was immunized four or more times and subsequently challenged. A significant degree of resistance against the challenge was produced. The injected worms lived in the peritoneal cavity for a short period, then died and disintegrated therein, thus obviating their inhabiting the circulatory system. The functional antigens were evidently derived from the metabolic products of the immunizing living schistosomes in the peritoneal cavity.The results of the present experiment indicate that the main immune mechanism induced by the intraperitoneal injection of living schistosomula and young adult worms is that which inhibits the development of the late stage of schistosomula and the early stage of adults which have originated from the challenge infection. This immune mechanism may be induced by the functional antigens either from both the schistosomula and adult worms or from the schistosomula alone.
The egg sorting function of the uterine bell ofPolymorphus minutus(Acanthocephala)
Authors: Whitfield P. J. 
Published: June 2009

An adult femalePolymorphus minutusreleases only mature eggs into the intestine of its final host. These eggs come from the pool of eggs in the body cavity of the worm which contains only about 30% of mature eggs, the rest being immature. An analysis of the age structures of the egg populations in the body cavity and the uterus shows that an assortment of mature and immature eggs has taken place as the eggs pass from the body cavity to the uterus. The uterus contains only mature eggs and these are the eggs which are about to be released. The only pathway whereby eggs can enter the uterus from the body cavity is through the uterine bell. This suggests that it is the uterine bell which is able to select mature eggs from the mixture of eggs in the body cavity.A uterine bellin vitroengages in precisely patterned muscular activity which propels eggs through its branching lumen. In one part of the bell (the grooves between the median wall cells and the lappets of the uterine duct cells), the patterned muscular activity passes mature eggs into the uterus and immature eggs back into the body cavity to complete their development. The greater length of mature eggs seems to be the character which enables them to be ‘recognized‘ by the uterine bell.
Gregarines found in cockroaches of the genus Blaberus
Authors: Peregrine Pauline C. 
Published: June 2009

1. A description of four new species of gregarine found in Blaberus discoidalis and Blaberus boliviensis is given. The species have been called Protomagalhaensia granulosae, Gregarina cubensis (from B. discoidalis), Protomagalhaensia blaberae and Gregarina princisi (from B. boliviensis).2. A discussion of the taxonomic status of the species in relation to one another and to Gregarina blattarum and Protomagalhaensia serpentula is given, and further work to elucidate this problem is suggested.
Experiments on the reproduction ofNippostrongylus brasiliensisin the rat intestine
Authors: Phillipson R. F. 
Published: June 2009

A method is described for producing unisexual infections ofN. brasiliensisin rats; this method was used primarily to obtain populations of virgin adult females. Experiments were carried out in which male worms were introduced to virgin females in the rat small intestine. The worms were recovered after periods varying from 30 min to 22 h and the females were examined for fertile egg production or other evidence of insemination.In some experiments a few females were inseminated within 30 min of being mixed with males, but for reliable results a period of over 1 h was necessary. Sperm were first deposited along the ventral wall of the vagina and there was evidence that a single insemination could fill the vagina. After 4·5 h the majority of females had been inseminated and this period was long enough for sperm to reach the seminal receptacle in one female. A minority of females had a few fertile eggs in the uterus by 5·5 h, and fertile eggs were being passed by 6·0 h after the introduction of males.Small numbers of males were introduced to an excess of virgin females in order to obtain information on the sexual capacity of males. These experiments indicated that males could, on average, fertilize one female every 2 h during the first 15–20 h. This potential was shown to be greatly in excess of the minimum requirements for maintaining the maximum fertile egg output of females in normal infections.
Temperature as a critical factor in the mating behaviour of the rat flea,Nosopsyllus fasciatus(Bosc.)
Authors: Iqbal Q. J. , Humphries David A. 
Published: June 2009

1. Both male and femaleN. fasciatusnormally require a blood meal before they will mate.2. Fed males do not attempt to mate with unfed females. It is suggested that the taking of a blood meal enables the female to provide a stimulus necessary for the male to show mating behaviour.3. UnfedNosopsyllusof both sexes will mate if subjected to a temperature between 30 and 35°C inclusive. Above 35° mating does not occur.4. Below 30°C mating occurs only if the fleas have previously been subjected to a temperature of 30°C or above. A temperature rise to the critical point thus acts as a trigger for an enabling process which continues after temperature has again fallen.5. It is suggested that the effect of a blood meal in enabling mating to occur may be explained by the fleas' experience, while on the host, of a rise in temperature to the level critical for mating.
Amino acid flux in the sporocysts ofCercaria emasculansPelseneer, 1906in vitro
Authors: Watts Stuart D. M. 
Published: June 2009

Quantitative paper chromatography and radioactive tracers were used to study the flux of alanine through the sporocysts ofCercaria emasculans in vitro. The following evidence indicates that simple diffusion is the main mechanism of permeation: (1) the sporocysts cannot accumulate alanine against a concentration gradient; (2) the concentration of alanine in the sporocysts is a direct linear function of the concentration of alanine in the external environment; (3) addition of 10−2M glucose to the medium does not enhance permeation; (4) neither heat-killing the sporocysts nor treating them with 10−3M iodoacetate slows the rate of permeation; (5) theQ10's for the permeation are similar to those to be expected in a process involving simple diffusion; (6) the amino acid molarities in the parasite and host tissuesin vivoare strikingly similar. No utilization of alanine during the course of 3 h incubations could be detected by autoradiography.The dynamic nature of the equilibrium between the sporocysts and the external environment is emphasized by the exchange of alanine that occurred even under isotonic conditions.Fresh sporocysts leaked alanine and proline during 1 and 4 h incubationsin vitro. The significance of this is not known.
Haemonchus contortus - haematological changes in lambs during prolonged exposure to daily and weekly doses of infective larvae
Authors: Pradhan S. L. , Johnstone I. L. 
Published: June 2009

Thirty-five lambs (14 weeks old), the progeny of Border Leicester rams mated with Border Leicester × Merino ewes were divided at random into two groups. Seventeen lambs received 3500 Haemonchus contortus larvae at weekly intervals (weekly group) and 18 lambs received 500 larvae each day (daily group). The dosage was decreased to 1400 and 200 larvae respectively after 8 weeks.The daily infection with a small number of larvae induced a severe anaemic condition with the blood picture falling to 7% PCV; 2% Hb conc. and 1·6m/mm3 RBC count in 78 days. The anaemia with weekly dosing of larvae was less severe with equivalent figures of 10–12% PCV; 4% Hb conc and 3·6m/mm3 RBC count.Two phases were observed in the changes in the sodium (Na+e) and potassium (K+e) electrolyte concentrations. In the first phase (K+e) increased and (Na+e) decreased, while in the second phase both electrolytes increased. The influx of young red blood cells into the circulation is considered as the factor responsible for these changes.
Nutritional requirements for protein synthesis during parasitic development of the entomophilic nematode Mermis nigrescens
Authors: Gordon Roger , Webster John M. 
Published: June 2009

Adult desert locusts were experimentally infected with a dose of 50 M. nigrescens ova and larval nematodes removed 14, 17, 21 and 24 days afterwards for in vitro radiotracer studies. These nematodes were incubated under controlled conditions either in a nutrient medium or in insect saline, which contained the appropriate 14C or 3H-labelled radioisotope. The rate of incorporation of the radioisotope into the proteins of the nematode was measured.The rate of incorporation of 14C-leucine into proteins was greatest for the 17- day-old larvae and this accorded with the in vivo growth pattern of the nematode. This isotope was incorporated less rapidly into proteins by the 14-, 21 and 24-day- old larvae, which synthesized proteins at approximately the same rates as each other. A non-linear rate of incorporation was manifest for each of the larval stages.Total dry weight and protein determinations showed that the nematode synthesizes relatively large quantities of non-proteinaceous reserves during the third week of infection, whilst proteins are preferentially synthesized between the 21st and 24th days of infection.The 17-day-old nematode larvae were able to incorporate six 14C-amino acids into proteins to varying degrees. Leucine was incorporated most effectively into nematode proteins, whilst glutamic acid was the least incorporated of the six amino acids.These nematode larvae could not effectively metabolize the 3H-dipeptide histidyl-leucine and incorporate its component amino acid residues into proteins. Similarly, a preparation of 3H-haemolymph proteins were not significantly metabolised and incorporated into proteins by the nematode. However, the nematode metabolized and incorporated an exogenous source of 14C-glucose into proteins at relatively high levels.Incorporation of 14C-luecine into proteins was seven times more rapid for nematodes incubated in buffered insect saline than for those incubated in a more complete nutrient medium.The dietary requirements of the nematode for protein synthesis were discussed in relation to their associated effects upon the host metabolism and an active transport of dietary amino acids into the nematode was postulated.We wish to thank Dr H. L. Speer and Dr K. K. Nair for their helpful suggestions regarding radioisotope techniques. Thanks are also due to the National Research Council of Canada for providing financial assistance (Grant No. A4679).
Gastro-duodenal motor and transit disturbances associated with Haemonchus contortus infection in sheep
Authors: Bueno L. , Dakkak A. , Fioramonti J. 
Published: June 2009

SUMMARYAbomasal and duodenal motility was investigated by electromyography in 4 lambs fitted with permanent abomasal and duodenal cannulae and infected twice with 25000 Haemonchus contortus larvae at an interval of 39 days. In addition, abomasal and duodenal pH, flow rate of digesta of the duodenum, and faecal water content were determined. The 80–90 min cycles of antral contractions were shortened for at least 3 weeks after infection. This was accompanied by a 26% increase in the number of duodenal migrating myoelectric complexes/day during the intra-parietal development of the larvae (10–12 days). Concomitantly, the duodenal flow of digesta increased from 215 ± 22 ml/h to 318 ± 15 ml/h 4 days after infection and was associated with a higher water content of the faeces. The frequency of the migrating myoelectric complexes, but not the duration of antral motor cycles (or the duodenal flow rate), was correlated with both gastric (P < 0·01) and duodenal (P < 0·05) pH after the first and second infections. The duodenal flow rate was correlated with the Cl− concentration of the abomasal contents (P < 0·01) and with the duodenal pH (P < 0·05). It is concluded that, (i) the duodenal motor disturbances associated with experimental H. contortus infection are related to the alterations in abomasal gastric acid secretion which occurs during the histotrophic phase of larval development and (ii) the increased duodenal flow is a consequence of ionic permeability changes of the gastro-intestinal mucosae.
Duration of immunity to East Coast fever (Theileria parva infection of cattle)
Authors: Burridge M. J. , Morzaria S. P. , Cunningham M. P. , Brown C. G. D. 
Published: June 2009

Forty-five cattle, which had recovered from EOF and been kept free from reexposure to infection for periods of 1–43 months, were given a single uniform lethal challenge using a stabilate prepared from triturated infected ticks. All withstood the challenge which killed the five controls. There was an increase in the incidence of mild febrile reactions with time since last exposure to T. parva, indicating a gradual loss of immunity in the absence of reinfection. The duration of the immunity was not related to the severity of the initial reaction.We are indebted to our colleagues on the Immunological Research on Tickborne Cattle Diseases and Tick Control Project, with whom we designed and carried out the experiment.
The distribution of Nippostrongylus brasiliensis in prolonged infections in lactating and neonatally infected rats
Authors: Connan R. M. 
Published: June 2009

In lactating rats examined 3 weeks post infection, adult Nippostrongylus brasiliensis were found in the duodenum close to the pylorus. Worms migrated from the predilection site, shown by Brambell (1965) and Alphey (1970) to be approximately 25% down the intestine, during the second week of infection. A similar migration took place in neonatally infected rats.It was suggested that the migration was an active response to immunological damage. It could be prevented by early betamethasone treatment but only modified by treatment given late in infection.
Eimeria tenella: experimental studies on the development of resistance to amprolium, clopidol and methyl benzoquate
Authors: Chapman H. D. 
Published: June 2009

SummaryThe development of resistance by the Houghton strain of Eimeria tenella to the anticoccidial drugs amprolium, clopidol and methyl benzoquate has been studied. Resistance to amprolium and clopidol developed more readily in experiments where a large number of coccidia were exposed to the drug, either by increasing the number of oocysts in the inoculum or by increasing the number of birds in the group. When 45 birds were given 2·0 × 106 oocysts, resistance to amprolium and clopidol appeared after 6 and 7 passages respectively. In previous experiments, under similar conditions, resistance to robenidine developed after 6 passages, suggesting little difference between these three drugs. Resistance to amprolium and clopidol arose gradually as the concentration of drug was increased, but resistance to methyl benzoquate appeared in a single step from sensitivity to high-level resistance. Both amprolium and clopidol-resistant lines showed an 8-fold reduction in drug sensitivity. Attempts to measure the degree of resistance by calculation of the ED50 were unsuccessful.
Boophilus microplus: rejection of larvae from British breed cattle
Authors: Koudstaal D. , Kemp D. H. , Kerr J. D. 
Published: June 2009

SummaryLarvae of Boophilus microplus were labelled with [32P] and used to study the rejection of larvae from British breed cattle with different levels of resistance. On animals of high resistance the loss of larvae due to grooming ranged from 9–54% during the first 24 h of infestation, and more time was spent grooming by these animals. Most of the grooming activity could be attributed to the presence of tick larvae and the presence of older tick stages did not increase the percentage of larvae lost. Grooming was directed to attached larvae and these could be removed. Animals of low resistance did not lose a significant number of larvae as a result of grooming, but all previously infested hosts lost a proportion of the larvae (18–39%) which could not be accounted for by grooming. This loss was greater than the total loss of larvae (11%) on animals not previously exposed to B. microplus.
The life-cycle, ultrastructure and mode of feeding of the locust amoeba Malpighamoeba locustae
Authors: Harry Owen G. , Finlayson L. H. 
Published: June 2009

The primary trophozoites of Malpighamoeba locustae excyst in the crop and midgut of the Desert Locust (Schistocerca gregaria) and then penetrate the epithelial cells of the midgut and caeca where they grow and multiply slowly. After about 10–12 days they leave the gut epithelium passively when the cells in which they have grown degenerate and are extruded. From the lumen of the gut they make their way into the lumen of the Malpighian tubules where they feed upon the brush border as extracellular parasites. No primary or secondary trophozoites were found in the haemocoele of the host.During the first few days in the Malpighian tubules the secondary trophozoites undergo a rapid series of divisions which enables them to double their numbers every 24 h so that by day 20–22 the lumen of the tubules is packed with cysts and trophozoites. The trophozoites phagocy-tose small pieces of brush border and numerous food vacuoles are present in their cytoplasm. The cytoplasm of the primary trophozoite contains the normal complement of cell organelles, a notable feature of which are the large, numerous mitochondria with their tubular cristae. When the trophozoites are ready to encyst they round up and begin to lay down a series of membranes which totally cover the trophozoite. Numerous storage granules are found in mature trophozoites which are about to encyst and these may be utilized in cyst wall production.
The role of the tegument of the metacercarial stage of Bucephalus haimeanus (Lacaze-Duthiers, 1854) in the absorption of particulate material and small molecules in solution
Authors: Higgins J. C. 
Published: June 2009

SUMMARYUptake by the tegument of metacercariae of Bucephalus haimeanus of both particulate material and small molecules in solution is demonstrated by the use of electron-dense tracers and autoradiographic techniques. Ruthenium red (RR) uptake involved pinocystosis and the formation of large, electron-lucent vesicles in the outer cytoplasmic tegument. RR lost its association with these vesicles and became freely dispersed within the cytoplasm as it passed through the outer cytoplasmic tegument, down the cytoplasmic bridges and into the tegumental cell bodies. Ferritin, iodinated insulin and iodinated human serum albumin were also located within the outer cytoplasmic tegument and ferritin collected beneath the inner plasma membrane of the outer cytoplasmic tegument. Horseradish peroxidase was not absorbed by the tegument although it bound strongly to the outer surface of the metacercariae. C-labelled glucose, phenylalanine, tryptophan and tyrosine were all detected in the outer cytoplasmic tegument.
Schistosoma mansoni: the activity and development of the schistosomulum during migration from the skin to the hepatic portal system
Authors: Wilson R. A. , Draskau Tove , Miller Patricia , Lawson J. Ruth 
Published: June 2009

SummaryThe activity patterns and changes in shape of schistosomula recovered from various locations during migration, are described. There is no significant increase in length during the period which worms remain in the skin. Rhythmic cycles of extension and contraction of the worm body are established soon after penetration. Worms newly arrived at the lungs are identical with skin worms of the same age. Within the lungs their maximum length increases to four times that of skin worms, an adaptation which is believed to facilitate migration through the lumina of blood capillaries. Worms recovered from the lungs and systemic organs on, and subsequent to, day 8 post-infection retain this capacity for elongation. When worms arrive at the hepatic portal system they undergo a process of shortening and there is a transient doubling in the duration of cycles of activity. It is suggested that this shape and activity change terminates migration by preventing escape of worms from the hepatic portal system via the liver sinuses. The stimulus which triggers the response is thought to be the high nutrient levels present in hepatic portal blood, but not in peripheral blood. The stimulus which terminates migration also probably initiates growth. Worms cultured in vitro undergo some increase in length, but have a significantly lower maximum length than lung worms of a corresponding age. Although cultured worms were active, the cycles of extension and contraction were much more erratic than those of in vivo worms. The worms shortened spontaneously after 8–10 days in culture. This shortening occurred marginally later than in the most rapidly migrating worms in vivo.
Biological controls in mixed trichostrongyle infections
Authors: Whitlock J. H. , Georgi J. R. 
Published: June 2009

SummaryThe parasite reaction phenotype of 80 lambs was determined with natural infection on pasture. These lambs were then assigned to outcome groups and randomized into treatment groups. Developing some simple but unusual analytical techniques it was possible to demonstrate that mixed natural infections of trichostrongyles with the chief biomass component Haemonchus contortus cayugensis protected against superinfections with 35000 infective larvae but protected against superinfections with 1000 infective larvae per day only within the limits characteristic of the enclosing barn ecosystem. The limits of the barn ecosystem were less constraining on more diathetic sheep than the natural pasture infection. Internal evidence from the experiment suggests that the interaction of sheep × pasture × infective trichostrongylid larvae constrains the parasite biomass in the host in more diathetic animals at significantly lower levels. Anaphylactoid ‘self-cure’ did not occur in this experiment but something like premunition certainly did.