bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gametogenesis and fertilization inDirofilaria immitis(Nematoda: Filarioidea)
Authors: Delves C. J. , Howells R. E. , Post R. J. 
Published: June 2009

SUMMARYGametogenesis inDirofilaria immitishas been studied principally by means of the aceto-orcein chromosomal squash technique, but with additional ultrastructural observations. A terminal germinative zone, in which a continuous and rapid division of germ cells occurs, has been identified in the gonoduct of both male and female worms. Approximately 20% of cells within these germinative zones were in arrested mitotic division following the incubationin vitroof excised gonads in 0·01% colchicine for 4 h. All primary spermatocytes within a 1–2 cm length of the testis proximal to the germinative zone were at the prophase of the 1st meiotic division. In the corresponding region of the ovary, the primary oocytes were similarly at the prophase of the 1st meiotic division in 75% of female worms examined but in the remaining 25% all primary oocytes possessed markedly less condensed, probably interphase nuclei. A possible hormonal control of the cyclical development of primary oocytes, but not primary spermatocytes inD. immitisis suggested. In most of the remaining length of the gonoducts beyond this region of cells at meiotic prophase, the chromatin material of both primary spermatocytes and oocytes is decondensed. Recondensation of chromosomes in the spermatocytes is observed just prior to entry into the seminal vesicle, where meiosis I is completed and meiosis II takes place. In the primary oocyte, completion of meiosis only occurs after fertilization within the seminal receptacle by an entire male gamete. Following the 2 meiotic divisions in the oocyte and subsequent extrusion of the 2 polar bodies, the haploid chromosome complement of the female unites with that of the male, re-establishing the diploid number of the zygote (2n= 10). Male chromosomes within the oocyte remain visible throughout late oogenesis and fusion occurs without the formation of pronuclei.
In vitro development of hydatid cysts from posterior bladders and ruptured brood capsules of equine Echinococcus granulosus
Authors: Rogan M. T. , Richards K. Sylvia 
Published: June 2009

SUMMARYA variety of morphological forms developed during monophasic culture of ruptured brood capsules of equine Echinococcus granulosus. Attached to some protoscoleces were small posterior bladders, with a surface ultrastructure of truncated microtriches, and these never developed a laminated layer. In contrast, small free vesicles of similar size and ultrastructure, but devoid of an attached protoscolex, produced a layer by 20–30 days. The surface ultrastructure of both these forms is similar to that of the protoscolex attachment stalk and the brood capsule lining, and posterior bladders and small free vesicles are considered to be derived from portions of the stalk±part of the brood capsule lining retained at protoscolex release. Also present were large vesicles interpreted from their size and surface anatomy as ruptured, everted brood capsules. When devoid of attached protosoleces these formed cysts each with a laminated layer, whereas similar vesicles with several attached protoscoleces did not develop a layer, or only very occasionally after 70 or more days. In contrast, a few large vesicles with a single attached protoscolex produced a laminated layer. The possibility that protoscolex attachment to stalk remnants or brood capsules inhibits the cystic development of these structures is discussed.
N-acetylation of biogenic amines in Ascaridia galli
Authors: Isaac R. E. , Eaves L. , Muimo R. , Lamango N. 
Published: June 2009

SUMMARYThe metabolism of 5-hydroxytryptamine (5-HT), octopamine (OA) and dopamine (DA) by adult male Ascaridia galli was investigated by incubating worms cut into 5 mm lengths with radio-isotope labelled amine. [14C]5-hydroxytryptamine and [14C]octopamine were taken up by the tissues and were metabolized to apolar products that co-chromatographed using both high-performance liquid chromatography and thin-layer chromatography with N-acetyl 5-hydroxytryptamine (NA5-HT) and N-acetyloctopamine (NAOA), respectively. N-acetylation was by far the most important reaction detected under these experimental conditions. A brief incubation of cut worms with [3H]dopamine resulted in the formation of a radio-isotope labelled metabolite that co-chromatographed with N-acetyldopamine (NADA) on reversed-phase high-performance liquid chromatography. The N-acetyltransferase activity towards 5-hydroxytryptamine and octopamine was detected in crude homogenates of male worms only when the co-substrate, acetyl CoA, was added to the reaction mixture. This enzyme activity appeared to be mainly localized in a 40 000 g supernatant fraction. The failure of previous studies to detect N-acetylation of biogenic amines in tissue homogenates of nematodes may have been due to the low levels of acetyl CoA present in these enzyme preparations.
Immunological characterization of cytoskeletal proteins associated with the basal body, axoneme and flagellum attachment zone ofTrypanosoma brucei
Authors: Woodward R. , Carden M. J. , Gull K. 
Published: June 2009

SUMMARYThe monoclonal antibody BS7, raised to bovine sperm flagellum cytoskeletal antigens in a previous study, is here reported to detect flagellum-associated structures inTrypanosoma bruceiandCrithidia fasciculata. Immunoblotting showed that BS7 cross-reacts with several cytoskeletalT. bruceiproteins but phosphatase treatment did not diminish this complex immunoblot reactivity. To characterize further the cross-reactive proteins recognized inT. brucei-cytoskeletons by BS7 each was excised from preparative gels and used as an immunogen for antiserum production. Two proteins, with apparent sizes around 43 and 47 kDa, produced antisera shown to be monospecific by immunoblotting totalT. bruceiflagellum preparations. Each of these detected the basal body-associated immunofluorescence inT. brucei. Identification of the smaller, 43 kDa, component as a basal body-associated product was supported by the behaviour of a second monoclonal antibody, BBA4, which was also shown to detect theT. bruceibasal body complex by immunofluorescence and immunoblots the 43 kDa polypeptide. These observations reveal new components of the trypanosome cytoskeleton. Also, they provide a further example of an immunological approach for identification of interesting, rare components of theT. bruceicytoskeleton starting from a complex mixture of proteins.
Richness and diversity of macroparasite communities in tropical eels Anguilla reinhardtii in Queensland, Australia
Authors: Kennedy C. R. 
Published: June 2009

SUMMARYThe prediction that richness and diversity of helminth communities would be greater in tropical fish was tested by analysing total and intestinal helminth communities in samples of Anguilla reinhardtii taken from 10 localities in tropical and semi-tropical freshwaters in Queensland, Australia. Comparison of findings with those from A. anguilla in the UK revealed that regional species richness was higher in Queensland and that helminth communities harboured a suite of common species, virtually all eel specialists, that were responsible for the observed higher levels of similarity between component communities. All measures of community richness and diversity adopted indicated that the poorest helminth communities in A. reinhardtii were comparable with the richest ones reported from the northern temperate A. anguilla. The richest communities in A. reinhardtii were more diverse than those reported from any other species of fish, whether marine or freshwater, to date, and were comparable with the communities found in some species of aquatic birds. Both tropical conditions and age and endemism of the host, i.e. the time hypothesis, were considered as explanations for this richness but neither could be favoured. A cautious approach to generalizations based on data from temperate regions only is advocated, and the need for more studies on tropical parasite communities is strongly emphasized.
Ex vivoevidence for PGE2and LTB4involvement in cutaneous leishmaniasis: relation with infection status and cytokine production
Authors: Milano S. , Arcoleo F. , Dieli M. , D'agostino R. , De Nucci G. , D'agostino P. , Cillari E. 
Published: June 2009

SUMMARYEx vivoculture of spleen cells from BALB/c mice infected with 2 × 106Leishmania major(L.major) promastigotes were cultured with ConcanavalinA (ConA) or leishmanial antigen (L. Ag) and tested for prostaglandin E2(PGE2) and for leukotriene B4(LTB4), in order to study their involvement in the evolution of cutaneous leishmaniasis and the connexion with lymphokine-mediated responses. The data were compared with those obtained in BALB/c mice protected againstL. majorby sublethal irradiation (550 rad; cured mice). In the unprotected BALB/c mice the levels of PGE2that were responsible for the depression of interferon-γ (IFN-γ) and tumour necrosis factor-α (TNFα) Th1-associated cytokines and for the relative increase in the interleukin-4 (IL-4) became higher and higher as the lesion progressed. On the contrary, the cured mice produced levels of PGE2similar to normal uninfected controls, high levels of TNFα and IFN-γ and low levels of IL-4. Elevated levels of LTB4were detected in the early stage of infection in the unprotected mice compared to cured ones, a sign of more intense inflammation and a stimulus for the recruitment of inflammatory cells. The observation that exogenous LTB4was able to enhance in vitro both Th1cytokines in cured mice and Th2cytokines in unprotected ones suggests that LTB4could act in the recruitment of the T cells already committed to Th1or Th2phenotype.
Mice infected with the larvae ofTaenia crassicepsexhibit a Th2-like immune response with concomitant anergy and downregulation of Th1-associated phenomena
Authors: Villa O. F. , Kuhn R. E. 
Published: June 2009

SUMMARYInfection of intermediate hosts with eggs of taeniid parasites results in a larval infestation known as cysticercosis. A number of studies have indicated that cysticercosis is associated with immunosuppression, although little is known about the mechanisms involved. In the present study, mice infected with the larvae ofTaenia crassicepswere found to exhibit a pronounced anergy, which preferentially affected T-cells located anatomically close to the parasite. This anergy was linked to late events in the T cell activation pathway; that is, stimulation through the T cell receptor(TCR)/CD complex by Concanavalin-A, or plate-bound monoclonal antibodies (mAb) to TCRαβ or CD3ε, or combinations of phorbol ester and ionomycin (all of which can bypass early membrane-related events), failed to fully activate T lymphocytes. The relative proximity of T cells to the parasite was directly related to upregulation of IL-4 and downregulation of IL-2 production. In addition, the profiles of parasite-specific Abs showed an exclusive increase of serum IgG1 during infection. Taken together, the data suggest that infection of mice with larvae ofT. crassicepsalters the balance of CD4+Th cells by upregulating Th2 and downregulating Th1 cells located in close proximity to the parasite.
Hypoxanthine: a low molecular weight factor essential for growth of erythrocyticPlasmodium falciparumin a serum-free medium
Authors: Asahi H. , Kanazawa T. , Kajihara Y. , Takahashi K. , Takahashi T. 
Published: June 2009

SUMMARYA low molecular weight factor in a basal medium essential for erythrocyticPlasmodium falciparumdevelopment in a serum-free medium using a cell growth-promoting factor derived from adult bovine serum was detected. The factor was hypoxanthine. The optimal hypoxanthine concentration for parasite growth was between 15 and 120 μM. The contribution of hypoxanthine to increased parasite growth was clearly evident in cultures on day 4. Among various low molecular weight supplements tested, adenine, adenosine, AMP, ATP, cyclic AMP, guanine, guanosine, inosine, inosine mono-phosphate, xanthine, NAD, NADH, NADP, NADPH and deoxyguanosine triphosphate showed a similar effect to that of hypoxanthine in the serum-free culture system. On the other hand, the addition of uric acid, FAD, thymidine, uridine, orotic acid, deoxythymidine triphosphate, deoxycytidine triphosphate, deoxyadenosine triphosphate, ribose-1-phosphate, or ethanolamine was not beneficial to the parasite growth. The results presented here will not only be of practical value, but will provide important information about the developmental requirements of the parasite.
Predisposition of mice to Heligmosomoides polygyrus and Aspiculuris tetraptera (Nematoda)
Authors: Scott Marilyn E. 
Published: June 2009

SUMMARYThe purpose of this study was to determine whether predisposition to Heligmosomoides polygyrus and Aspiculuris tetraptera (Nematoda) exists within a naturally infected population of mice. A breeding mouse population was housed in a spacious arena in which endemic infections of H. polygyrus and A. tetraptera were present. H. polygyrus were over-dispersed in the mouse population. Prevalence reached 100% by the age of 3 weeks; intensity of infection increased to a peak in the 10 to 15-week-old mice, and remained high throughout life. A group of 73 mice was treated with pyrantel pamoate, and the expelled worms were counted. Mice were returned to the arena. Daily egg production was monitored 4, 8, 12 and 14 weeks after treatment. Mice were then killed and numbers of H. polygyrus and A. tetraptera were counted. Significant positive correlations were detected between numbers of H. polygyrus at first treatment and at necropsy, indicating the existence of predisposition. Similar results were obtained for A. tetraptera. Correlations improved when data were analysed by age class of mice. Analyses based on egg-count data during reinfection did not support the hypothesis of predisposition, however. A. tetraptera and H. polygyrus burdens were significantly correlated only in 3 to 4-week-old mice at the time of the treatment.
Caecal threadworms Trichostrongylus tenuis in red grouse Lagopus lagopus scoticus: effects of weather and host density upon estimated worm burdens
Authors: Moss R. , Watson A. , Trenholm I. B. , Parr R. 
Published: June 2009

SUMMARYTrichostrongylus tenuis eggs were counted in faeces from individually marked wild red grouse for 8 years. Egg counts varied seasonally and annually. In some years, a sudden increase in mid-April was consistent with delayed maturation of larvae which had overwintered in the birds in a hypobiotic state. A more gradual increase in summer was probably due to uninterrupted maturation of larvae ingested then. Despite 30-fold year-to-year variation in mean egg counts, relative differences in egg counts among known individuals within years tended to persist across years. Rainfall in previous summers explained much of the year-to-year variation in egg counts, probably because parasite recruitment was greatest during wet summers. Grouse density was only weakly related to worm egg counts. The data were not consistent with the hypothesis that the cyclic-type population fluctuation in red grouse numbers observed at the time of this study was caused by the parasites.
Hatching, survival, activity and penetration efficiency of second-stage larvae of Anguillicola crassus (Nematoda)
Authors: Thomas K. , Ollevier F. 
Published: June 2009

SUMMARYHatching of eggs of Anguillicola crassus was studied at temperatures between 5 and 30°C. Hatching occurred between 10 and 30°C and the incubation time was inversely related to temperature. Survival, spontaneous and excitatory rate of activity of 2nd-stage larvae of A. crassus were also affected by temperature. The percentage of larvae eaten by Paracyclops fimbriatus was not always influenced by the activity of the larvae. Penetration efficiency into the haemocoel of the intermediate host was highest for freshly hatched larvae and declined gradually with age. Completely non-active larvae were still able to penetrate, although penetration efficiency was lower.
The distribution of developing Brugia pahangi and Brugia malayi larvae within the dorsal longitudinal flight muscles of Aedes aegypti and Mansonia uniformis
Authors: Beckett Evelyn B. 
Published: June 2009

1. The distribution of larvae within the dorsal longitudinal muscle fibre groups of A. aegypti infected with subperiodic B. malayi or B. pahangi and of M. uniformis infected with the former parasite was studied with the aid of serial sections.2. In all experiments the top bundles of fibres contained fewer parasites than either the middle or lowest bundles, but whereas most parasites were concentrated in the middle bundles in A. aegypti there was no significant difference in M. uniformis between the bottom and middle fibre bundles. The lowermost fibre was not the most heavily parasitized of the dorsal longitudinal group.3. Nothing is known of what determines whether or not a particular fibre becomes parasitized, but it was concluded that the distance between the fibre and the gut (from which the parasites emerge to travel to the muscle) is not the principal factor.I am very much indebted to Mr Cheong Weng Hooi and his colleagues for collecting and processing mosquitoes in Kuala Lumpur and to Mrs J. Oliver who finished the processing in Liverpool. I am grateful also to Dr W. W. Macdonald for his advice and help in all stages of this work and to Miss M. A. Johnson who assisted with the care of the A. aegypti colony and prepared the diagrams for this paper.
Ascaris, people and pigs in a rural community of Jiangxi Province, China
Authors: Weidong Peng , Xianmin Zhou , Xiaomin Cui , Crompton D. W. T. , Whitehead R. R. , Jiangqin Xiong , Haigeng Wu , Jiyuan Peng , Yang Yang , Weixing Wu , Kaiwu Xu , Yongxing Yan 
Published: June 2009

SUMMARYA longitudinal investigation on natural populations of Ascaris in humans and pigs and an investigation of soil contamination with Ascaris eggs were carried out from June 1993 to June 1994 in 2 villages, Manhu area, Xinjian County, Jiangxi Province, China. Results from these studies indicate that although human ascariasis is endemic there is significant fluctuation in both prevalence and the mean number of eggs/g faeces (epg) of the communities. Fluctuation of age-stratified prevalence and mean epg was detected in children but not in most adult groups. Most cases of human ascariasis were judged to involve low intensities of infection and a typical overdispersion distribution pattern was observed through the year. It was estimated that during the year, nearly half of the eggs discharged in the environment came from infections in children aged between 2 and 15 years which accounted for about 30% of the total population. Soil in and around houses and in vegetable gardens was found to be contaminated by Ascaris eggs and this situation remained relatively stable throughout the year. Monthly developmental rate of Ascaris eggs in soil was detected and the results suggest that the fluctuation in prevalence observed during the year should be directly attributed to the effect of seasonality of egg development. Features of Ascaris infection in pigs were found to be similar to those in humans except for a lower mean intensity of infection. The possibility of cross-infection of Ascaris between human and pig hosts is discussed.
Serotonin and acetylcholine: further analysis of praziquantel-induced contraction of magnesium-paralysed Schistosoma mansoni
Authors: Blair K. L. , Bennett J. L. , Pax R. A. 
Published: June 2009

SUMMARYThe nature of stimulus-induced flaccid paralysis produced in Mg2+-paralysed Schistosoma mansoni was investigated. Serotonin induced a dose-dependent, heterologous flaccid paralysis with an IC50 of 600 nm. This flaccid paralysis was a function of the extracellular Mg2+:Ca2+ ratio and was reversible. Tonic contractions produced by phorbol-12,13- dibutyrate or 60 mM K+ were reversed by the application of serotonin and flaccid paralysis was induced. These actions of serotonin were mimicked by forskolin and synergized by IBMX but the potassium channel blocker, 3,4-DAP, did not produce flaccid paralysis. When Mg2+-paralysed parasites were stimulated with 3,4-DAP, IBMX produced a dose- dependent flaccid paralysis with an IC50 of 11 μm. Membrane permeable analogues of cAMP and cGMP did not synergize with IBMX. Cholinergic agonists, but not other inhibitory substances, prevented the serotonin- and forskolin-induced and the IBMX-synergized flaccid paralysis but not that produced by praziquantel. The possible interactions of these agents with the muscle are discussed.
Two new species of the genus Haematoloechus (Digenea: Plagiorchiidae) from Rana occipitalis (Gunther) in Ghana
Authors: Rees Gwendolen 
Published: June 2009

Haematoloechus (Haematoloechus) exoterorchis sp.nov. and H. (H.) micrurus sp.nov. have been found in the lungs of Rana occipitalis (Gunther) in South Ghana.62·5% of the frogs were infested with one or other or with both species.The two species occupy different positions in the lungs of the host. H. (H.) exoterorchis is cylindrical and is wedged, anterior end foremost, into the alveoli. H. (H.) micrurus is flattened and remains free in the central lumen of the lung.In the former case the wall of the alveolus, containing the worm, becomes stretched to a thin membrane.The morphology of both species is described with reference to their different habitats.A brief discussion of the genus is included.I am most grateful to the University of Ghana and to the staff of the Zoology Department at Legon for the facilities which they placed at my disposal and without which the work could not have been done.
External stimuli and intracellular signalling in the modification of the nematode surface during transition to the mammalian host environment
Authors: Proudfoot L. , Kusel J. R. , Smith H. V. , Kennedy M. W. 
Published: June 2009

SUMMARYPrevious work has shown that the surface of infective larvae of parasitic nematodes will not bind the fluorescent lipid analogue 5-N(octadecanoyl)aminofluorescein (AF18) until after exposure of the parasite to mammalian tissue-culture conditions. In this study, culture media which are permissive or non-permissive for the acquisition of lipophilicity for AF18 were altered in order to examine possible stimuli involved. This showed that external alkaline pH and high sodium ion concentration were highly stimulatory. The internal signalling pathways which may be involved in the surface alteration were then examined using agents which are known to affect intracellular signalling in mammalian cells. The results indicated that elevation of cGMP levels was stimulatory whereas inhibition of a putative Na+/H+ antiporter or calcium mobilization was inhibitory, and it is argued that high intracellular levels of cAMP may be inhibitory. Whilst the precise effects of the agents used on nematode cells remain to be established, these results provide a framework for the examination of the processes involved in the modification of the nematode surface which takes place immediately after the infection event.