bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dendrogaster tasmaniensis sp.nov. (Ascothoracida) from the sea-star Allostichaster polyplax (Müller and Troschel)
Authors: Hickman J. L. 
Published: June 2009

The genus Myriocladus Okada is considered to be a synonym of the genus Dendrogaster Knipowitsch.The female and male of a new species, D. tasmaniensis sp.nov. from the sea-star Allostichaster polyplax (Müller and Troschel), are described.Appendages interpreted as antennae are present in the female, male and ascothoracid larva of the new species.A brief account is given of the manner in which the larva of D. tasmaniensis sp.nov. enters and escapes from the host.
Variation in the ixodid tick, Ixodes arboricola Schulze & Schlottke 1929
Authors: Haarløv Niels 
Published: June 2009

1. Seventy-three females, 1 male, 20 nymphs and 1 larva of Ixodes arboricola Schulze & Schlottke, 1929 were found on a juvenile enfeebled starling (June, 1933, Denmark).2. Range of variability of employed systematic characteristics of this species has been checked, and it was found impossible to preserve the following subspecies of I. arboricola, muscicapae, domesticus and bogatschevi.3. Between length and breadth of idiosoma of female, and between lengths of legs I and III (excluding trochanter and coxa) the ratio was found to be almost linear. A deformed leg II is described as a case of regeneration.4. I. arboricola, I. passericola, I. dryadis, and I. strigicola are regarded as synonyms and have all been incorporated in the species I. arboricola, the habitat of which is birds' nests in tree cavities.For supplying material for this study I wish to thank Professor M. Christiansen, State Veterinary Serum Laboratory, Copenhagen; Dr B. Hubendick, Director of ‘Naturhistoriska Museet’, Gothenburg; Dr S. L. Tuxen, Head of the entomological department of ‘Universitetets zoologiske Museum’, Copenhagen, and Dr Glen M. Kohls, Sanitarian director for the loan of P. Schulze's former collection of ticks.I am most thankful to Dr Don Arthur, for advice and critical reading of the manuscript.
The effect of host lactation on a second infection of Nippostrongylus brasiliensis in rats
Authors: Connan R. M. 
Published: June 2009

Rats were infected with 1000 larvae at the time of mating and they were given a second infection while suckling a new-born litter some 3½ weeks later. Although they did have significantly more worms than immune controls such rats were nevertheless highly resistant to challenge with infective larvae. However, when challenged with adult worms, immunized lactating rats were unable to eliminate the second infection.That the failure of self-cure in this case was not because adult worms are less antigenic in lactating rats was shown in the third experiment. Lactating rats were immunized by infection either with adult worms only or with larvae allowed to complete their life-cycle. When subsequently challenged with infective larvae during the same lactation, both groups were equally resistant. It is therefore concluded that in lactating rats the gut phase of N. brasiliensis infection is in some way protected from the self-cure mechanism. This may be due either to absence of an essential factor operating late in the process, or to the presence of a potentiating factor which allows the worms to survive.The author would like to thank Professor W. I. B. Beveridge in whose Department this work was carried out, and the Agricultural Research Council for their financial assistance. It is also a pleasure to acknowledge the technical assistance of Mr J. A. Wilson and Mr P. W. Holmes.
Schistosoma mansoni: the development of the cercarial tegument
Authors: Hockley David J. 
Published: June 2009

Young cercariae were covered with a thin nucleated primitive epithelium which was lost when the true tegument appeared beneath it. The tegument was at first similar to the primitive epithelium in that it was a nucleated, cytoplasmic syncytium but it could be distinguished from the primitive epithelium by its thickened outer membrane and by the layer of interstitial material beneath its basal membrane. The tegumental nuclei became pycnotic and disappeared and, at about the same time, nucleated subtegumental cells became continuous with the tegument. Two types of small, dense bodies were formed in the subtegumental cells and passed into the tegument. Later in development the tegument became filled with dense, granular material and spines were formed. The fully developed cercarial tegument was covered with a surface coat of fibrous material which was specifically attached to the outer membrane of the tegument.The observations described in this paper formed part of a thesis approved by the University of London for the Degree of Ph.D.
The distribution of larvae of Brugia malayi and Brugia pahangi in the flight muscle fibres of Aedes aegypti and Mansonia uniformis
Authors: Beckett Evelyn B. , Macdonald W. W. 
Published: June 2009

1. The distribution of filarial larvae in the dorsoventral and dorsal-longitudinal muscle fibre groups was studied in serial sections of mosquitoes of a susceptible strain of Aedes aegypti infected with Brugia pahangi or subperiodic B. malayi and of wild-caught Mansonia uniformis mosquitoes containing the latter parasite.2. The experiments showed that more larvae were situated in the dorsal-longitudinal muscle than in the dorsoventral and that the difference in numbers was highly significant.
Changes in the food intake and body weight of protein-malnourished rats infected with Nippostrongylus brasiliensis (Nematoda)
Authors: Crompton D. W. T. , Walters D. E. , Arnold Susan 
Published: June 2009

SUMMARYThe daily food intake and related changes in body weight were measured in young rats which were fed on synthetic diets containing 1% (3 experiments), 2% (4 experiments) and 20% (1 experiment) casein respectively. Some rats were infected with Nippostrongylus brasiliensis and allowed to feed ad libitum, some remained uninfected and were allowed to feed ad libitum while others, which were matched by initial weight with rats from the infected group, remained uninfected and were given only the same amount of food as that consumed during the previous 24 h by their infected partners. No significant differences were detected between the rats before the start of the infection. Thereafter, the food intake of the infected undernourished rats was usually found to be significantly lower and the loss of body weight significantly greater than those of the uninfected rats. In infection periods of relatively long duration, the pair-fed uninfected rats did not lose as much weight as their infected partners even though their food intake (1% and 2% casein) was the same. Although the food intake, and consequently the weight, of infected rats fed on the diet containing 20% casein were significantly less than in their uninfected partners, no significant differences were observed between the weights of the infected and pair-fed rats fed on this diet.
Na+–K+ transport, motility and tegumental membrane potential in adult male Schistosoma mansoni
Authors: Fetterer R. H. , Pax R. A. , Bennett J. L. 
Published: June 2009

SUMMARYOuabain applied to adult male Schistosoma mansoni causes a large, non-reversible tension increase of the parasite's musculature and elimination of spontaneous contractions. The tension increase and the time-course of tension development caused by ouabain are dose dependent with significant effects obtained at 3 × 10−6m. Digoxin and digoxigenin act in a similar manner with a relative potency of ouabain ≃ digoxin > digoxigenin. Lowered temperature as well as substitution of Li+ for Na+ increases muscle tension. The membrane potential recorded from the ventral tegument is also affected by treatments which interact with Na+–K+ transport systems. Ouabain (0·1 mm) causes a rapid depolarization without a significant effect on membrane resistance. The tegument is depolarized by temperatures below 30 °C. The effect of temperature is readily reversible and the temperature sensitivity is eliminated by pretreatment with ouabain. Substitution of Li+ for Na+ also causes a depolarization of the tegument. Tracer experiments show both an increase in Na+ and a decrease in K+ in the parasite within 10 min after treatment with ouabain (1 × 10−5m). Decreasing temperature of the bathing medium also causes an accumulation of Na+ as well as a decrease in the animals. The above results indicate a significant role for active Na+–K+ transport in muscle contraction and in maintenance of the tegumental membrane potential. The data also suggest that the Na+–K+ transport in S. mansoni may be electrogenic.
A model of schistosomiasis incorporating the searching capacity of the miracidium
Authors: Coutinho F. A. B. , Griffin M. , Thomas J. D. 
Published: June 2009

SUMMARYThis paper describes a modification of the model for the transmission of schistosomiasis proposed by Macdonald (1965), which allows the snail host-locating efficiency of the miracidium to be taken into account. The modified model allows for a choice of miracidia efficiency. If it is assumed that the miracidia are inefficient hunters then the resulting model is very sensitive to perturbations; relatively small changes in snail numbers not only cause appreciable changes in the percentage of snails infected but result in attainment of the threshold (the point at which schistosomiasis ceases to be endemic). If, however, the miracidia are efficient snail hunters then the model is much less sensitive to perturbations; here the percentage of snails infected is much less affected by changing snail numbers, and the threshold is much more difficult to reach by reducing snail numbers. It is argued that, on the whole, the empirical data give more support to the latter model, although there are some circumstances under which the former model might apply. However, even with these modifications it is considered that the Macdonald model does not provide a satisfactory explanation of field observations.
Endogenous stages of a ‘chick embryo-adapted’ strain ofEimeria tenella
Authors: Long P. L. 
Published: June 2009

A strain ofE. tenellawhich had been passaged serially in 42 batches of chick embryos appeared to have lost its ability to produce the characteristically large second-generation schizonts in both the embryonic chorioallantois and in the chicken caeca. Numerous small schizonts (10–16 µm in diameter), which contained 8–30 small merozoites, replaced the large second-generation schizonts characteristic of this species. The small schizonts were numerous 3–5 days after inoculation and were restricted to epithelial cells of the embryo allantois when sporozoites were inoculated via the allantoic cavity. These schizonts also occurred in epithelial cells of the caeca of chickens given oocysts via the crop. Cell reactions in the chicken caeca in response to infection were minimal. Numerous minute lesions were present in the chorioallantois 4–6 days after inoculation; these were associated with the small schizonts and later with gamonts and oocysts. The strain reproduced well in the embryo but failed to induce gross pathogenic effects and no mortality resulted from the infection.Only two passages of this strain in chickens were needed to restore a high degree of pathogenicity. This change was accompanied by the reappearance of the characteristically large second-generation schizonts in the tunica propria of the caecal wall.
On the reported occurrence of an ecdysone-like steroid in the freshwater snail, Biomphalaria glabrata (Pulmonata; Basommatophora), intermediate host of Schistosoma mansoni
Authors: Bayne C. J. 
Published: June 2009

Attempts to repeat the isolation of an ecdysone-like steroid from Biomphalaria glabrata revealed that some of the manipulations described by Muftic (1969) were physically impossible to repeat. With modified procedures no ecdysone-like steroid was found. The original publication gives scant attention to certain experimental details. Some sections of the text bear very close resemblance to earlier publications by different authors. The amount of substance claimed to have been isolated, and the long survival period claimed for Schistosoma mansoni larvae in vitro, are claims which, amongst others, seem highly unlikely a priori. All attempts to contact Muftic have proved to be futile. It is suggested that the paper is, at least in part, erroneous and that any future reference to it should clearly indicate its suspected invalidity.Despite these results, it is considered likely that future investigations will demonstrate physiological roles for steroids in snails.I wish to acknowledge the stimulating communications of Drs E. L. Hansen, M. Voge, R. E. Thorson, C. S. Richards, J. N. Kaplanis, G. Nace, R. Monroe, and of E. Chernin, who first brought this matter to my attention. Theanalytical steroid work could not have been done nor interpreted without the considerable time and effort willingly given by Drs F. Kohen and R. Counsell of the University of Michigan College of Pharmacy. My snail populations were supplemented with snails from the tanks of Mrs B. Caveny. Technical help was given by E. Perisho, G. Lindsay and P. LoVerde. Financial support was kindly provided by Dr J. B. Burch. This investigation was supported in part by the United States-Japan Cooperative Medical Science Program administered by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health, Department of Health, Education and Welfare, grant N.I.A.I.D. AI-7364, and in part by NSF grant GB-29315. Improvements were made to the first draft of the manuscript after it was critically read by Drs E. L. Hansen, F. Kohen, M. Voge, E. Chernin, R. E. Thorson and J. N. Kaplanis.
Experimental infections of the domestic fowl with a variant of Eimeria praecox from the Ceylon jungle fowl
Authors: Long P. L. , Fernando M. A. , Remmler O. 
Published: June 2009

A species of Eimeria from the Ceylon jungle fowl (Gallus lafayetti), at first thought to be a new species of Eimeria, has been identified as a strain of E. praecox. Oocysts of this jungle fowl strain were slightly larger than those of E. praecox, being 23·2 × 19·9 μm, but the endogenous stages were similar. The strain reproduced poorly in the domestic fowl but oocyst production was improved by treating the chickens with beta-methasone. A single infection of chickens with the strain of jungle fowl origin protected against challenge with the original culture and E. praecox, but did not cross-protect against E. acervulina. The name E. praecox var. ceylonensis is proposed for this strain of Eimeria.The criteria used to identify new species of Eimeria are discussed.
Immunity to intestinal tapeworms: the rejection of Hymenolepis citelli by mice
Authors: Hopkins C. A. , Stallard H. E. 
Published: June 2009

Approximately 90% of Hymenolepis citelli cysticercoids given to 6-week-old male CFLP mice by stomach tube became established. Equally high recovery rates were obtained from administering 1, 3 and 6 cysticercoids.In 1-worm infections worms increase in weight until about day 25–28 post infection. After a few days at maximum weight (mean weights of worms 24–42 mg) there is a small, 10–25%, decrease in weight, after which there is little change in weight up to day 90 (as long as studied).One-worm infections survived without loss until day 30, after which a slow loss occurred, but only in two experiments, both with older mice, did loss exceed 50% by day 80. In 3-worm infections worms were rejected between days 17 and 30, but loss varied from 50 to 80% during this period in replicate experiments. With 6-worm infections rejection occurred over a shorter period (days 17–22), was more uniform between experiments and was more complete, over 75% of worms being lost. In both 3- and 6-worm infections a residual population, usually of only a single worm, persisted in 20–50% of the mice until the end of the experiments (day 63–78).Cortisone prevented loss of worms from both 3- and 6-worm infections; worms continued to grow until day 25 ± 2 (as in 1-worm infections), by which time they were considerably larger than (the surviving) worms in mice not receiving cortisone. The biomass (worm burden per mouse) remained constant from day 25 to 55 in mice receiving cortisone.The results are discussed with particular reference to: H. diminuta and the evidence that mice do mount an immunological response against tapeworms in the intestine; the existence of an antigenic threshold in mice; the apparent existence of a similar rejection pattern in a natural population of H. citelli in Peromyscus maniculatus, and hence the importance of immunity as a factor preventing gradual increase in number of tapeworms in the intestine during the life of a host.
The cell coat ofCrithidia fasciculata
Authors: Brooker B. E. 
Published: June 2009

SummaryA prominent filamentous and granular cell coat is associated with the plasma membraneof haptomonads ofCrithidia fasciculataattached to the cuticular lining of the hindgut ofAnopheles gambiae. This surface material is completely absent from morphologically identical haptomonads from the mosquito foregut and from rosettes in culture. On the basis of these observations, it is suggested that cell coat formation is dependent on suitable environmental conditions. A cytochemical staining technique indicates the presence of carbohydrates in (a) the cell coat, (b) the outer leaflet of the plasma membrane of haptomonads from all locations and (c) small cytoplasmic vesicles and multivesicular bodies in all haptomonads. It is suggested that these cytoplasmic organelles represent stages in the intracellular pathway for material ingested by pinocytosis rather than elements involved in surface coat formation.
The growth of secondary infections ofHymenolepis microstomain mice: the effect of various primary infection regimes
Authors: Howard R. J. 
Published: June 2009

SummaryGroups of mice were infected with 1,5 or 10 cysticercoids ofHymenolepis microstoma. Infections were terminated with the anthelmintic ‘Zanil’ after 5, 15 or 30 days and the mice challenged with 6 cysticercoids. The growth of the worms in the secondary infections decreased as either the intensity (number of cysticercoids administered) or duration of the primary infections increased. It is postulated that the results have an immunological basis.
Echinococcus granulosus equinus: an ultrastructural study of the laminated layer, including changes on incubating cysts in various media
Authors: Richards K. Sylvia , Arme C. , Bridges Janine F. 
Published: June 2009

SUMMARYThe microfibrillate component of the laminated layer of Echinococcus granulosus equinus contains, except for the zone adjacent to the germinal layer, aggregates of electron-dense bodies displaying a sub-structure of electron-lucent spheres. The tegumentary syncytial cytoplasm contains randomly distributed electron-dense granules, many occurring near the apical plasmalemma, although exocytosis was rarely seen. Granules, similar in size and sub-structure to the bodies of the aggregates, also occur in the internuncial connexions and tegumentary cytons, suggesting that they may be produced in the cytons and released into the laminated layer via the internuncial connexions and tegumentary cytoplasm. Cysts incubated for 0·5–2·5 h in serum- and non-serum-containing media showed differences from non-incubated cysts. The distal half of the syncytium contained a progressive increase in the number of granules (distal:proximal 1·9:1 at 2·5 h; cf. 1:1 in non-incubated cysts), and exocytosis of granules into the laminated layer adjacent to the cyst had occurred. This cannot be attributed wholly to serum proteins. Cysts incubated for 21 h appeared ‘normal’, suggesting re-establishment of an equilibrium. Since the matrix of the laminated layer is considered homologous to the glycocalyx of other cestodes, the possible protective role played by the granules/bodies, characteristic of Echinococcus spp., is discussed.
The uptake in vitro of dyes, monosaccharides and amino acids by the filarial worm Brugia pahangi
Authors: Chen S. N. , Howells R. E. 
Published: June 2009

SUMMARYThe uptake in vitro of various substances by Brugia pahangi was investigated using infective larvae obtained from Aedes aegypti and worms removed from Meriones unguiculatus at 2, 3, 10, 20 and 90 days post-infection. Worms incubated in growth medium 199 containing 1% Trypan blue possessed demonstrable dye in the oral orifice, the anterior oesophageal lumen and the external openings of the vulva and the cloaca or anus but the dye was not found in the gut lumen even after incubation for 24 h. No uptake of ferritin particles into the intestine of the worms was found and no fluorescence could be demonstrated in the gut lumen of worms incubated in medium containing 50% (v/v) fluorescein isothiocyanate-conjugated calf serum for up to 24 h. Trypan blue uptake by the gut of Aspiculuris tetraptera was clearly observed after incubation for several hours. The uptake of D-glucose and L-leucine by B. pahangi was demonstrated using autoradiographic and scintillation counting techniques and incorporation into worm tissues was detected. Glucose was found to be readily incorporated in the apical, glycogen-rich areas of the myocytes of worms of all ages studied and in the uterine epithelium of the adult female. In contrast, a lower incorporation of D-glucose was found in the eggs, embryos and vas deferens and especially in the gut. The incorporation of L-leucine occurred throughout the tissue of the worms during a 30 mm incubation. Labelling was also located over the surface of the cuticle of the worms, when incubated for a period of 15 to 60 mm in L-[3H]leucine. Scintillation counting techniques demonstrated that there was no uptake of 14C-labelled L-glucose or sucrose by B. pahangi. The data presented on the uptake in vitro of nutrients or other compounds by infective larvae and adult stages of B. pahangi did not demonstrate an intestinal route of uptake but indicated that the transcuticular route of uptake may be employed.
Different levels of acquired immunity to Schistosoma mansoni in two strains of hamster
Authors: Smith M. A. , Clegg J. A. 
Published: June 2009

SummaryA primary infection with Schistosoma mansoni, of 5 or more weeks duration, stimulated a high level of resistance to a challenge infection in the WO outbred strain of golden hamster. In sharp contrast, the LGN strain showed no statistically significant immunity to reinfection in most experiments and where detected the level of resistance was only about half that observed in the WO strain. Immunity to reinfection was assayed with the lung recovery method which assesses resistance a few days after challenge and with the conventional perfusion assay which measures immunity 6 weeks after challenge. Wide differences in the immune response to S. mansoni in different strains of the same host species have not been reported previously.
Transplantation ofHymenolepis diminutainto naive, immune and irradiated mice
Authors: Hopkins C. A. , Zajac A. 
Published: June 2009

SummaryAlmost 100% of 7- to 10-day-oldHymenolepis diminutabecame established when surgically transplanted from donor mice into the duodenum of naive recipient mice. Transplanted tapeworms survived 8–12 days, by which time they had survived much longer in total than they would have done in the donor. Mice previously immunized by a primary infection rejected transplants within 4 days. Sub-lethal irradiation (550 rad) delayed rejection by immune mice but such mice still rejected worms much more quickly than did naive mice.Surgery was shown to delay by 2–3 days the rejection of worms by naive mice, and the importance of circumventing surgery by administering the wormsper osis emphasized.Prospects for reconstituting irradiated immune mice are consideredvis-à-viswork with nematodes, and the differences which, on present knowledge, appear to exist between nematode and cestode rejection are briefly discussed.