bluuebunny/crossref_metadata_2025_split huggingface dataset:
Axenic cultivation and characterization ofLeishmania mexicanaamastigote-like forms
Authors: Bates P. A. , Robertson C. D. , Tetley L. , Coombs G. H. 
Published: June 2009

SUMMARYA new method is described which has made possible the long-term axenic cultivation ofLeishmania mexicanaamastigotelike forms in Schneider'sDrosophilamedium supplemented with 2% (v/v) foetal calf serum. Unlike previous methods, it utilizes direct culture of parasites obtained from the lesions of infected animals rather than adaptation of promastigotesin vitro. Ultrastructural (possession of megasomes), biochemical (cysteine proteinase activity and gelatin SDS-PAGE banding pattern) and infectivity (in vivo) data are presented which show the close similarity of the cultured forms to lesion amastigotes. The axenically cultured forms grew optimally at a temperature of 32–33 °C, providing further evidence for their amastigote nature. It was found that adjustment of the pH of the growth medium to 5·4 was required in order to retain the amastigote morphology of the cultured parasites. This supports the notion that leishmanial amastigotes are acidophiles.
The dynamics of trickle infections withAncylostoma ceylanicumin inbred hamsters
Authors: Brailsford T. J. , Behnke J. M. 
Published: June 2009

SUMMARYTrickle infections with a hamster-adapted strain of the hookwormAncylostoma ceylanicumwere studied by administering doses of 5–30 larvae twice weekly to inbred DSN hamsters. The worm burdens were regulated at very low levels, and this was found to be independent of the size of the infective dose. It is likely that there is some turnover of adult worms during trickle infection, as larvae of all stages were recovered from most time-points. This regulation is immunologically mediated and both the worm burdens and fecundity were increased in hamsters that were immunosuppressed by cortisone treatment. A trickle infection regime also induced a 67% protective immunity to a single subsequent challenge. The resistance that occurred during trickle infections was, however, incomplete, and some worms were found to survive in hamsters that had been repeatedly infected for over 10 weeks. Thus, although hamsters are capable of regulating the infection, some worms are capable of surviving the host immune effectors.
The use of suckling mice to isolate and growGiardiafrom mammalian faecal specimens for genetic analysis
Authors: Mayrhofer G. , Andrews R. H. , Ey P. L. , Albert M. J. , Grimmond T. R. , Merry D. J. 
Published: June 2009

SUMMARYA simple technique is described for preparation ofGiardiacysts from faecal samples, the growth of trophozoites in suckling mice and the isolation of trophozoites for genetic analysis by allozyme electrophoresis. In total, 125 new isolates ofGiardiahave been collected from human and animal sources over a wide geographical area of South Australia and the Northern Territory of Australia. A number of long-established axenized isolates ofG. intestinalisbelonging to Groups I and II also adapted to grow in suckling mice. These findings indicate that suckling mice are permissive hosts for a variety of genetically dissimilar but morphologically similar organisms of theG. duodenalistype and that thisin vivotechnique may be less selective than isolation byin vitroculture. The use of suckling mice has revealed that infections can be composed of mixed genotypes and that isolation and purification techniques can be selective. Allozymic interpretation is essential to reveal the genetic complexity of such mixtures
The secreted and somatic proteinases of the bovine lungwormDictyocaulus viviparusand their inhibition by antibody from infected and vaccinated animals
Authors: Britton C. , Knox D. P. , Canto G. J. , Urquhart G.M. , Kennedy M. W. 
Published: June 2009

SUMMARYProteinase activities were examined in extracts and excretory–secretory (ES) products of the infective and adult stages of the cattle lungworm,Dictyocaulus viviparus. Multiple enzyme activities were identified from each source, as defined by pH optima, substrate specificities, inhibitor effects and substrate gel electrophoresis. Serine-, cysteine- and metalloproteinases were identified, secreted materials being more active against protein substrates per unit protein than were extracts, and the particular proteinases produced varied with the developmental stage of the parasite. The antigenicity of these parasite proteinases was demonstrated by the inhibition of enzymic activity with Protein G-purified serum IgG antibody from both infected and vaccinated hosts and in the retardation of enzyme migration on electrophoresis of enzyme–antibody complexes. For the adult products, this confirmed that the enzymes concerned were of parasite origin, and not host-derived. These results argue for investigation ofD. viviparusproteinases as targets for the antibody response in the limitation of parasite-mediated tissue damage and as the active principle behind the anti-D. viviparusvaccine.
Effects of testosterone onHeterakis spumosainfections in mice
Authors: Harder A. , Wunderlich F. , Marinovski P. 
Published: June 2009

SUMMARYThis study describes the effects of testosterone (Te) on the intestinal nematodeHeterakis spumosain mice. The course ofHeterakisinfections is apparently under Te-control. At high circulating Te-levels as occurring in intact males, Te-treated females, and Te-treated castrated males, the period of release ofHeterakiseggs in mouse faeces is greatly extended and the number of eggs released per unit time is markedly elevated in comparison to low Te-levels, as found in untreated females and castrated male mice. Also, the onset of the patent period occurs earlier in Te-treated mice. Testosterone also accelerates development and growth of both female and male worms ofHeterakisin mice. Thus, young adult male worms can be observed in the upper colon of Te-treated castrated male mice on day 21 post-infection (p. i.), whereas, at that time, only L4larvae are present in Te-untreated male castrates. Testosterone also favours the survival of nematodes in hosts. In untreated male castrates, the number of worms present on day 7 p.i. (L2larvae) is approximately two thirds higher than that found on day 21 p.i. However, such a reduction in the number of worms does not occur in Te-treated castrated mice during the same period of time. The early phases of the life-cycle ofHeterakis, i.e. hatching in the small intestine and final settling of L2larvae in the upper colon are independent of Te. Also, Te does not affect motility and even slightly reduces the fecundity of adult female wormsin vitro. Our data suggest that Te and/or Te-metabolites and/or Te-induced host factor(s) accelerate the development and growth ofH. spumosaand favour the survival ofHeterakisin the colon of mice.
Cytotoxic activity of 13-hydroxyoctadecadienoic acid againstToxoplasma gondii
Authors: Henderson W. R. , Chi E. Y. 
Published: June 2009

SUMMARYRecent data indicate that platelets may play an important role in the host defence againstToxoplasma gondiiinfections.T. gondii-stimulated human platelets release thromboxane A2(TXA2) and 12-hydroxyeicosatetraenoic acid (12-HETE) from arachidonic acid and 13-hydroxyoctadecadienoic acid (13-HODE) from linoleic acid (Yonget al.1991; Hendersonet al.1992). We have previously demonstrated that the eicosanoid TXA2has potent cytotoxic activity againstT. gondiitrophozoites (Yonget al.1991). In this study, we examined whether 12-HETE, 13-HODE, and linoleic acid also have toxoplasmacidal activity. 13-HODE at concentrations ≥ 10−8M rapidly induced cytotoxic changes inT. gondii. Ultrastructural changes induced by 13-HODE inT. gondiiincluded an initial leakage of cytoplasmic contents into a space between the inner and outer parasite bilayer membrane units which was followed by intracellular vacuolation and loss of cytoplasmic contents. In contrast, linoleic acid and 12-HETE lacked toxoplasmacidal activity at 10−10–10−6M concentrations. These data indicate that 13-HODE, a product of linoleic acid metabolism, has potent cytotoxic activity againstT. gondii; this toxoplasmacidal activity may be important in the inflammatory response to this pathogen.
Immune control of murine coccidiosis: CD4+and CD8+T lymphocytes contribute differentially in resistance to primary and secondary infections
Authors: Rose M. E. , Hesketh P. , Wakelin D. 
Published: June 2009

SUMMARYThe effect of treatment with monoclonal antibodies (Mabs) which deplete CD4+or CD8+T lymphocytes, on infections withEimeriaspp. was examined in NIH mice. Treatment with anti-CD4 Mab increased susceptibility to primary infections withE. vermiformisorE. pragensisand reduced the subsequent resistance of the mice to homologous challenge. Similar treatment of immune mice did not affect their resistance to re-infection but this was reduced in mice depleted of CD8+T lymphocytes. In mice immunized withE. vermiformisthe effect of CD8+-depletion was very slight, apparent only as the presence of small numbers of oocysts in the faeces of some mice; in mice immunized withE. pragensisthere was a small, though significant, increase in oocyst production, compared with controls and anti-CD4-treated groups. These results confirm the importance of mechanisms involving the function of CD4+T lymphocytes in the control of primary infections withEimeriaspp. and indicate that CD8+cells play some part in the expression of resistance to reinfection. They also show that a major part of this resistance was not affected by either of the treatments given.
Proteinases ofTrichomonas vaginalis: antibody response in patients with urogenital trichomoniasis
Authors: Bózner P. , Gombošová A. , valent M. , Demeš P. , Alderete J. F. 
Published: June 2009

SUMMARYImmunoprecipitation combined with electrophoresis in gelatin-polyacrylamide gels was successfully used for detection of antibodies against numerous proteinases ofTrichomonas vaginalisin infected patients. The method proved to be highly specific as anti-proteinase antibodies were absent in women with negative cultivation ofT. vaginalisand no history of trichomoniasis. Sera of 71% and vaginal washes of 86% patients with trichomoniasis were positive for these antibodies. In vaginal washes, but not in sera, antibodies were partly complexed with proteinases, possibly of trichomonad origin. It was also shown that serum antibodies as well as local anti-proteinase antibodies persisted for weeks after patients had been cured.
Antibodies against somatic antigens and excreted/secreted products ofBrugia pahangiin rats with patent and non-patent infections
Authors: Fletcher C. , Wu C. C. 
Published: June 2009

SUMMARYThe humoral responses of Sprague–Dawley rats infected withBrugia pahangiwere examined for up to 6 months after infection by ELISA, immunoblotting, and IFAT. In 2 experiments, 50% and 62·5% of rats developed patent, microfilaraemic infections. Mean adult worm burdens at autopsy were approximately 2% of the inoculum, and only patent rats yielded living adult worms. IgG antibody levels against crude somatic extracts (CSE) of all parasite stages and against adult excreted/secreted (ES) products were significantly higher in patent than non-patent rats. Both patent and non-patent rats produced anti-microfilarial surface antibody, as revealed by immunofluorescence. Immunostaining of Western blots by early infection sera showed no consistent difference in recognition of infective larval (L3) antigenic components by IgG or IgM antibody between eventually-patent and eventually-non-patent rats. By 26 weeks, however, patent rats recognized more components. The data suggest that antibodies against L3, adult, and microfilarial somatic antigens, ES antigens and microfilarial surface antigens do not correlate with the subsequent development of microfilaraemia in any individual rat.
The effects of tumour necrosis factor on host—parasite relations in murineMesocestoides corti(Cestoda) infection
Authors: Jenkins P. , Spiers S. , Dixon J. B. , Carter S. D. , May S. 
Published: June 2009

SUMMARYThe regulatory role of tumour necrosis factor (TNF) was investigated in murine infection with tetrathyridia ofMesocestoides corti. Recombinant TNFα reduced macrophage larvicidal activityin vitro. M. cortiprimed mice for TNF release in response to bacterial lipopolysaccharide (LPS)in vivo. TNF activity was amplified 100-fold at 14 days post-infection (p.i.), with a further rise at day 28 p.i. Maximal inflammatory reaction was observed histologically in the liver at the height of TNF activity. Hepatic necrosis was located within inflammatory foci, but not within the vicinity of the parasite itself, suggesting that TNF may contribute to the pathogenesis of infection. Peritoneal cells from infected mice, when stimulated with tetrathyridiain vitro, showed a 4-fold increase in TNFα activity at day 14 p.i. However, when peritoneal cells were stimulated with LPSin vitro, a marked increase in TNFα secretion was observed at 2 months post-infection followed by a slow decline. It is suggested that impaired macrophage effector function, previously attributed to endogenous endotoxin, which gains access to peritoneal macrophages through an inability of the liver to detoxify endotoxin, may be mediated through TNFα.
Interspecific differences in the nematode surface coat betweenMeloidogyne incognitaandM. arenariarelated to the adhesion of the bacteriumPasteuria penetrans
Authors: Davies K. G. , Danks C. 
Published: June 2009

SUMMARYSpores of the bacteriumPasteuria penetransadhered to second-stage juveniles of bothMeloidogyne incognitaandM. arenaria, but in standard attachment assays far fewer adhered to the latter species. Similarly, a polyclonal antibody was shown not to recognize the surface coat ofM. arenariabut did recognize the surface coat ofM. incognita. Although the incubation of whole, intact 2nd-stage juveniles ofM. incognitain a series of detergents and protein-denaturing agents at room temperature did not reduce the number of spores adhering after exposure to the bacterium, incubation in buffer (PBS) alone at 100 °C for 2 min did. Immunoblotting of cuticle extracts onto nitrocellulose and probing the blots with antibody showed that the antibody recognized a large protein ofMr80 kDa and a series of smaller proteins of approximately 43 kDa onM. incognitawhich were not recognized in extracts fromM. arenaria. As incubation of the 2nd-stage juveniles in antibody prohibited spore attachment it is suggested that these proteins may be involved in spore adhesion. Large differences exist betweenM. incognitaandM. arenariain the amounts of surface-associated proteins on the 2nd-stage juvenile cuticle.
Purification and properties of phosphoenolpyruvate carboxylase from Molinema dessetae (Nematoda: Filarioidea)
Authors: Loiseau P. M. , Gayral P. , Petek F. 
Published: June 2009

SUMMARYThe presence of phosphoenolpyruvate (PEP) carboxylase (EC 4.1.1.31), an enzyme at the branchpoint of glycolysis and the Krebs cycle was detected in the Filaria Molinema dessetae. This enzyme has not previously been identified in Helminths, which have so far been found to only possess a phosphoenolpyruvate carboxykinase (EC 4.1.1.32). This enzyme had a level of activity comparable to that of pyruvate kinase, and was relatively less active than enzymes such as malate dehydrogenase or lactate dehydrogenase. We propose here a method of purification of M. dessetae PEP-carboxylase. When purified to electrophoretic homogeneity, the enzyme had a molecular weight of 64 kDa. Kinetic studies indicated that the carboxylation reaction had an optimal pH of 5·8. The enzyme was inhibited by cations such as Fe2+, Zn2+, Cd2+, Cu2+ but required the presence of Mg2+ or Mn2+. The enzyme was thermostable. The apparent Km value of 2·38 mmol for phosphoenolpyruvate for the carboxylation reaction was higher than previously reported values. The Km value for KHCO3 was found to be 1·6 mmol. PEP-carboxylase did not catalyse the reverse reaction.
Pharmacological profile of the 5-hydroxytryptamine receptor ofFasciola hepaticabody wall muscle
Authors: Tembe E. A. , Holden-Dye L. , Smith S. W. G. , Jacques P. A. M. , Walker R. J. 
Published: June 2009

SUMMARY5-HT is a candidate for the excitatory transmitter at the neuromuscular junction in trematodes includingFasciola hepatica.This study has determined the response of a muscle strip preparation fromFasciola hepaticato 5-HT and a range of agonists that distinguish between the vertebrate receptor 5-HT subtypes. 5-HT increased the resting tone and the rhythmic activity of the muscle strip. Of the 19 compounds tested, only 10 had an effect similar to 5-HT and all but 2 of these were tryptamine compounds. 5-HT was more potent than tryptamine whilst 4-OH-tryptamine had no effect, suggesting that the response is mediated by a 5-HT rather than a tryptamine receptor. 5-Fluorotryptamine and 5-carboxyamidotryptamine were the most potent agonists. 8-OH-DPAT also mimicked the effect of 5-HT, though less potently. Assuming that these agents elicit their response through a common receptor, this suggests the presence of a 5-HT receptor with similar properties in terms of agonist recognition as the vertebrate 5-HT1class of receptor involved in controllingFasciolamuscle motility.
Trypanosoma (Nannomonas) congolense: molecular characterization of a new genotype from Tsavo, Kenya
Authors: Majiwa P. A. O. , Maina M. , Waitumbi J. N. , Mihok S. , Zweygarth E. 
Published: June 2009

SUMMARYTrypanosoma (Nannomonas) congolense comprises morphologically identical but genetically heterogeneous parasites infective to livestock and other mammalian hosts; three different genotypes of this parasite have been described previously. Restriction enzyme fragment length polymorphisms (RFLPs) in both kinetoplast DNA minicircle and nuclear DNA sequences, and randomly amplified polymorphic deoxyribonucleic acid (RAPD) patterns have been used here to demonstrate the existence of another type of T. (N.) congolense that is genotypically distinct from those that have so far been characterized at the molecular level. A highly repetitive, tandemly arranged DNA sequence and oligonucleotide primers, for use in polymerase chain reaction (PCR) amplification are described, which can be used for specific identification of the trypanosome and its distinction from others within the Nannomonas subgenus.
Leishmaniasis epidemiology: the theory catches up
Authors: Dye C. 
Published: June 2009

SUMMARYUntil recently, almost all studies of leishmaniasis epidemiology were qualitative and descriptive. But now that the natural history of manyLeishmaniaparasites is quite well known, there is growing interest in quantitative analysis. In this paper I use mathematical models in conjunction with field data to try to answer a wider range of questions than has previously been possible with descriptive techniques, and to sharpen some of the outstanding questions for laboratory workers. This is done with reference to the persistence and resilience of canine leishmaniasis, the maintenance of virulence poly morphisms inLeishmaniapopulations, and the possible existence of cycles of human kala-azar. I conclude by posing a set of problems under three headings: diagnosis of infection (as distinct from disease), natural immunity toLeishmaniainfection in the vertebrate host, and genetic variation in the parasite population. Some solutions from the laboratory can be found in the companion paper by Black (1992).
Malaria-a neglected disease?
Authors: Marsh K. 
Published: June 2009

SUMMARYIn situations where malaria eradication is not an option in the foreseeable future the emphasis must be on the control of morbidity and mortality due to malaria. Under such circumstances drawing a distinction between malarial parasitization and malarial disease may be important for workers in both field and laboratory. This concept is explored from the points of view of the epidemiological picture of malaria in endemic populations, the factors which may influence progression to disease and the processes which mediate disease.
Intestinal nematode infections in children: the pathophysiological price paid
Authors: Cooper E. S. , Whyte-Alleng C. A. M. , Finzi-Smith J. S. , MacDonald T. T. 
Published: June 2009

SUMMARYThe mechanism by which small animals such as rodents resist or eliminate nematode parasites requires mucosal in flammation as the final effector of the immune response. The resulting freedom from chronic infection may be worth the price of short-term illness. Putative vaccines which attempt to enhance the natural effect will have to take into account the inflammatory cost to the host. Human helminthiases involve a more stable equilibrium between host and parasite. The medical literature on hookworm disease and clinical ascariasis describes, for the former, some chronic inflammatory effects correlated with worm burden, but for the latter a less quantified or predictable set of detrimental effects. We describe a current, systematic study of the inflammatory response to whipworm infection, in which anaemia, growth retardation and intestinal leakiness are viewed as predictable consequences related to infection intensity. There is evidence for the absence of cell-mediated immunopathology. However, a specific, IgE-mediated local anaphylaxis may, at least partly, mediate the deleterious effects. Increased numbers of mucosal macrophages may also contribute to the chronic, systemic effects through their output of cytokines. Similar attempts to show the mechanisms of pathogenesis and quantify the effects of hookworm disease should be undertaken.
Cyclosporin A: antiparasite drug, modulator of the host-parasite relationship and immunosuppressant
Authors: Chappell L. H. , Wastling J. M. 
Published: June 2009

SUMMARYCyclosporin A (CsA), a cyclic undecapeptide with powerful properties of immunosuppression, acts on parasitic infections in laboratory animals in various ways. The outcome of drug administrationin vivovaries with timing of treatment relative to infection, route of administration, dose and number of treatments applied. CsA is clearly antiparasitic against malaria, schistosomes, adult tapeworms, metacestodes and filarial nematodes. By contrast, it acts as an immunomodulator against trypanosomes andGiardia, by exacerbating infection; in the case ofLeishmaniaspp. the drug acts variously. In some other infections CsA acts both as an antiparasite drug and as an immunosuppressant (Toxoplasma, avian coccidiosis and gastrointestinal nematodes).
Immune-dependent chemotherapy of schistosomiasis
Authors: Fallon P. G. , Cooper R. O. , Probert A. J. , Doenhoff M. J. 
Published: June 2009

SUMMARYHost immune responses have been shown to enhance the efficacy of several schistosomicidal drugs. The evidence derives mainly from experiments onSchistosoma mansoniinfections in the mouse with their immune status variously modulated; this review emphasises praziquantel (PZQ), which is now the main drug used for treatment of human schistosomiasis. Electron microscopy and indirect immunofluorescence indicate that PZQ disrupts the integrity of the surface membranes ofS. mansoni, particularly those covering the dorsal tubercles of adult male worms, and this causes antigens which are the targets of antibody attack to be revealed. We review the evidence that twoS. mansoniantigens in particular are implicated in the immune-dependent action of PZQ: a 200 kDa glycoprotein and a 27 kDa antigen with non-specific esterase activity.