bluuebunny/crossref_metadata_2025 huggingface dataset:
The evolution of inducible defence
Authors: Harvell C. D.
Published: June 2009

Defences against parasites are characterized by inducible, amplifiable responses, often with a memory component. Inducible defences with similar properties are common in a variety of other types of interactions, for example many aquatic invertebrates produce inducible structural defences against their predators and competitors. Most inducible defences have the following properties: (1) a threshold of activation; (2) an amplification of response with increasing stimulus; (3) a memory component. Specificity, amplification and memory are the basis for defining a defence as ‘immune’ (Klein, 1982), and these properties are present in both the vertebrate and invertebrate internal defence responses to pathogens. Invertebrates differ in the absence of immunoglobulins and therefore in reduced specificity. Although the reduced specificity of invertebrate internal defence systems is often viewed as proof of their ‘primitiveness’, the differences in defence systems of vertebrates and invertebrates may be more related to their respective selection regimes than to phylogeny. The syngeneic recognition system of vertebrates functions to recognize small departures from self, such as would arise from neoplasia. Are vertebrates under more intense selection from neoplasia, perhaps due to a greater incidence of hormonal imbalance or hypersensitivity reactions? The invertebrate internal defence systems are all less discriminating than the vertebrate, but there are marked differences in degree of discrimination depending on whether the group is colonial or not. Even the phyla of colonial animals with quite simple body plans, the sponges and cnidarians, have a more discriminating recognition system than the phyla of solitary animals with more complex body plans, such as the molluscs and arthropods. The primary effectors of all invertebrate responses to parasites are encapsulation and phagocytosis, although in some phyla there are specific antibacterial proteins that can also be induced. A primary effector of the vertebrate immune system is also based on phagocytosis, but is mediated largely by immunoglobulins. Although memory is a widespread property of inducible defence systems, the mechanisms, underlying memory components are unknown except in the vertebrate immune response. The function and adaptiveness of many of these accelerated or amplified second-set responses remain unclear, although it is tempting to conclude that a memory component is a beneficial adaptation to multiple, intermittent stimuli. From this review I conclude that the conditions that favour the evolution of inducible defences include: (1) an intermittent, unpredictable selective regime; (2) selection for a ‘camouflaged’ defence, to slow parasite counter-adaptation; (3) reliable cues and (4) high costs of defence.
Genetic exchange and evolutionary relationships in protozoan and helminth parasites
Authors: Tait A.
Published: June 2009

The study of genetic exchange systems and the use of genetic analysis has been relatively limited in parasites leading to considerable gaps in our basic knowledge. This lack of knowledge makes it difficult to draw firm conclusions as to how these systems evolved. An additional problem is also raised by the difficulties in defining evolutionary distances particularly with the unicellular protozoa, using classical ultrastructural and cytological criteria. While these difficulties have by no means been overcome, the use of rapid sequencing techniques applied to the ribosomal genes has allowed measurement of evolutionary distances, and considerable advances in our understanding of the genetic exchange systems in a few parasitic protozoa have recently been made. The conclusions from these recent sets of analyses are reviewed and then examined together in order to discuss the evolution of genetic exchange systems in parasitic protozoa. The evolutionary distances defined by ribosome sequence analysis show that parasites are an extremely divergent group, with distances which, in some cases, are orders of magnitude greater than the distances between mammals and fish; furthermore these studies suggest that the parasitic protozoa or their free-living ancestors are extremely ancient. These findings support the view that parasitism has occurred independently many times and that the parasitic life-style has been adopted by evolutionarily distinct groups. The recent observation of a non-obligatory genetic exchange system in the diploid but evolutionarily ancient kinetoplastid Trypanosoma brucei suggests that diploidy and meiosis are extremely old. The observation, in parasitic protozoa and helminths, that selfing or non-obligatory mating is a common feature suggests that these processes may be strategies to overcome the cost of meiosis. In this context, the question of what selective forces maintain genetic exchange is discussed.
Selection and evolution of virulence in bacteria: an ecumenical excursion and modest suggestion
Authors: Levin B.R. , Edén C. Svanborg
Published: June 2009

Why do parasites kill their hosts? During this past decade, research in three different areas; evolutionary ecology, medical microbiology, and population genetics has provided theory and data that address this and related questions of selection and the evolution and maintenance of parasite virulence. A general theory of parasite–host coevolution and the conditions for selection to favour parasite virulence has been put forth. Considerable advances have been made in elucidating the mechanisms of pathogenicity and inheritance of virulence in bacteria. The population genetic structure and the relation ship between pathogenic and non-pathogenic forms has been determined for a number of species of bacteria. We critically review these developments and their implications for questions of selection and the evolution and maintenance of virulence in bacteria. We postulate how selection may operate on specific types of bacterial virulence and present a general protocol to experimentally test hypotheses concerning selection and the evolution of virulence in bacteria.
Endogenous superoxide dismutase activity in twoBabesiaspecies
Authors: Becuwe P. , Slomianny C. , Valentin A. , Schrevel J. , Camus D. , Dive D.
Published: June 2009

Babesia hylomysciandB. divergenswere studied for superoxide dismutase (SOD) activity by enzyme assay and isoelectric focusing (IEF). In the two Babesia species, parasite-associated SOD is cyanide-insensitive and inhibited by H2O2, indicating that iron is the cofactor metal. Measurements of SOD activity from purified parasites show that the SOD activity detected inBabesiais, for the main part, due to an endogenous enzyme.
Physiological studies on trematodes—lipid fractions inGastrothylax crumenifer
Authors: Goil Madan M.
Published: June 2009

1. The different lipid fractions inGastrothylax crumeniferafter starvation for 8–10 hr. have been estimated.

2. The percentages of different fractions in the total ether extract were found to be: acetone-insoluble material 16, unsaponifiable matter 25, saturated fatty acids 5, unsaturated fatty acids 20, glycerol 2 and unidentified lipids 32.

3. The above percentages of lipid fractions have been compared with the corresponding data for different parasites obtained by other workers.
Cytological and cytochemical studies onCytamoeba bacteriferaLabbé, 1894
Authors: Lehmann D. L.
Published: June 2009

Cytamoeba bacteriferafrom urodeles (Batrachoseps attenuatus, Aneides lugubris, A. flavipunctatusandDicamptodon ensatus) show a thin peripheral ring of DNA and a less definite, heterogeneous central portion after Feulgen treatment; toluidine blue reveals a similar configuration. Exposure to DNA-ase and RNA-ase, followed by toluidine blue and Feulgen treatment, substantiates the localization of DNA; RNA is present in small quantity and restricted to the periphery of the parasite.

Mitochondria (2–5μ long rod-shaped, central bodies) can be detected with Janus Green B, and osmium tetroxide yields a dark central mass of rods and granules as well as peripheral granules; Sudan Black IV is without action. Zymohexase and acid phosphatase can be detected by cytochemical means, but peroxidase, lipase, urease and alkaline phosphatase were not noted.

From the evidence presented,C. bacteriferais considered a living entity and is tentatively relegated to the Piroplasmida.

The writer would like to express his appreciation to Dr R. S. Bray of the American Foundation for Tropical Medicine, Harbel, Liberia, for his counsel and suggestions.
Analysis of the complete sequence of a muscle calcium-binding protein ofSchistosoma mansoni
Authors: Stewart T. J. , Smith A. L. , Havercroft J. C.
Published: June 2009

The complete sequence of the cDNA encoding a 20 kDa calcium-binding protein ofSchistosoma mansoni(Sm20) has been determined. The predicted amino acid sequence contains 4 EF hand domains but examination of the predicted secondary structure of Sm20, together with the specific residues in each calcium-binding domain, suggests that only 1 EF hand (domain IV) is functional. Sm20 is most homologous to calmodulin, troponin C and the regulatory light-chain of myosin, particularly those of invertebrates. However, troponin C and the regulatory light-chain of myosin can be distinguished from Sm20 by size and by their differential levels of expression during the life-cycle. Sm20 also appears to be distinct from calmodulin but may be functionally equivalent to the soluble sarcoplasmic calcium-binding proteins of molluscs and crustacea which may act as a reservoir for calcium in muscle. Sm20 is encoded by a small multi-gene family whose members are clustered within a 15 kb region of the genome. A 20 kDa antigen, cross-reactive with Sm20, is expressed inSchistosoma haematobium, Fasciola hepaticaandParagonomus mexicanus.
Aerobic resistance ofTrichomonas vaginalisto metronidazole inducedin vitro
Authors: Tachezy J. , Kulda J. , Tomková E.
Published: June 2009

Aerobic resistance ofTrichomonas vaginalisto metronidazole was inducedin vitroby anaerobic cultivation of drug-susceptible trichomonads with low concentrations of the drug (2–3 μg/ml) for 50 days. Minimal lethal concentrations (MLC) for metronidazole of the resistant derivatives were high in aerobic susceptibility assays (MLC = 216–261.5 μg/ml) but low in anaerobic assays (MLC = 4.2–6.3 μg/ml), surpassing MLC values of their parent strain approximately 50-fold and 3-fold under aerobiosis and anaerobiosis, respectively. Sensitivity to metronidazole under anaerobic conditions and activity of the hydrogenosomal enzyme pyruvate: ferredoxin oxidoreductase indicated that the resistance was of the aerobic type. Dependence of the resistance manifestation on O2was further confirmed by susceptibility assaysin vitroperformed in defined gas mixtures of different oxygen content (1–20%). Five percent concentration of O2proved to be the threshold required for resistance demonstration and the MLC values further increased with increasing O2concentrations. Thein vitro-induced resistance was also demonstratedin vivoby subcutaneous mouse assay. The dose of metronidazole needed to cure 50% of infected mice (DC50) was 223 mg/kg × 3 for resistant derivative MR-3a but 6.6 mg/kg × 3 only for its drug-susceptible parent strain. The metronidazole – resistant strains developed in this study correspond by their properties to drug-resistantT. vaginalisstrains isolated from patients refractory to treatment, and promise to be a useful tool in the study of 5-nitroimidazole aerobic resistance.
Immunocytochemical evidence for the presence of substance P-like peptide in Diphyllobothrium dendriticum
Authors: Gustafsson M. K. S. , Nässel D. , Kuusisto A.
Published: June 2009

Substance P immunoreactivity (SP-IR) was detected in the nervous system of the gull-tapeworm Diphyllobothrium dendriticum. The distribution of the SP-IR neurons in the plerocercoid differs from that of other peptidergic and aminergic neurons in the worm. As well as occurring in the ganglionic commissure and along the two main nerve cords, SP-IR neurons are located laterally to the main nerve cords but not dorsally or ventrally. The SP-IR neurons have projections extending to the surface. Bipolar SP-IR neurons with processes to the surface also occur in the tip of the scolex. A sensory function for the SP-IR neurons is suggested.
Transcripts of the multidrug resistance genes in chloroquine-sensitive and chloroquine-resistantPlasmodium falciparum
Authors: Ekong R. M. , Robson K. J. H. , Baker D. A. , Warhurst D. C.
Published: June 2009

Homologues of the mammalian multidrug resistance gene have been identified in isolates and clones ofPlasmodium falciparumand designatedpfmdr1andpfmdr2.Mutations inpfmdr1have been associated with chloroquine resistance but confirmation could not be obtained in a genetic cross. We have examined the copy number and expression ofpfmdr1andpfmdr2in chloroquine-sensitive and -resistantP. falciparumand have found no relationship between the copy number of either gene and chloroquine resistance. However, a marked correlation was seen between levels of mRNA transcribed for each gene and chloroquine resistance. Two transcripts ofpfmdr1were detected, and in the asexual blood cycle an 8 kb transcript appeared first, followed by the appearance of a 7 kb species.
A quantitative framework for evaluating the effect of community treatment on the morbidity due to ascariasis
Authors: Medley G. F. , Guyatt H. L. , Bundy D. A. P.
Published: June 2009

There is growing emphasis on the use of community treatment to reduce the level of morbidity caused by helminth infection. The design of chemotherapy programmes, in terms of frequency of treatment and proportion of the community treated, would be assisted by a quantitative framework which enabled the morbidity reduction achieved by different approaches to be compared. The present study describes a model developed for this purpose which embodies two innovative features. First, a quantitative score of morbidity (the proportion of individuals harbouring an intense infection) is used to rate the success of a programme and, second, the distribution of helminths in the host population is generated by a mechanism that allows the distribution to change dynamically as a function of both treatment and reinfection. The model behaviour, using values typical ofAscaris lumbricoides, indicates that the benefit derived from community chemo- therapy increases non-linearly with the coverage and efficacy of treatment.
The effect ofGiardia lambliatrophozoites on trypsin, chymotrypsin and amylasein vitro
Authors: Seow F. , Katelaris P. , Ngu M.
Published: June 2009

Giardia lamblialocalize and multiply in the small intestine and may cause acute or chronic diarrhoea with malabsorption of fat, protein and other nutrients. Abnormal pancreatic function has been documented in giardiasis and trophozoites directly inhibit pancreatic lipase activityin vitro. The aim of this study was to examine the effect ofGiardiatrophozoites on pancreatic trypsin, chymotrypsin and amylase activityin vitro. Axenically culturedGiardiatrophozoites (Portland-1 stock) were incubated with a range of concentrations of trypsin, chymotrypsin and amylase and enzyme activity assayed over time. Tryptic activity was decreased after incubation withGiardiatrophozoites. This reduction was time dependent and linear over the incubation period of 2 h. At a trypsin concentration of 18 BAEE units/ml, there was a 35.5±4% reduction in enzyme activity after 2 h compared to controls. The total amount of activity lost was proportional to the initial trypsin concentration up to 185 BAEE units/ml. At this initial concentration, the activity was reduced by 46.5±3 units/ml after 2 h. Above this concentration, little further loss of enzyme activity was seen. To investigate the nature and specificity of this effect, similar experiments were conducted using killed trophozoites and with a related protozoan.Trichomonas vaginalis. No loss of enzyme activity was evident. Media previously incubated for 2 h with trophozoites did not diminish tryptic activity. Trophozoites had no effect on chymotrypsin or amylase activities over the range of concentrations tested.Giardiatrophozoites directly diminish pancreatic tryptic activityin vitro, by an active process which appears specific and not mediated via a secretory product. This mechanism may enhance parasite survival in the small intestine by allowing trophozoites to escape destruction by luminal proteases and may also contribute to malabsorption.
The impact of schistosomiasis on human nutrition
Authors: Stephenson L.
Published: June 2009

This article reviews studies that examine the negative effects of urinary and intestinal schistosomiasis on the following nutritional parameters in humans: urinary and faecal blood and iron loss, anaemia and haemoglobin levels, proteinuria, child growth and adult protein-energy status, physical fitness, physical activity, appetite and symptomatology. The conclusions reached are (1) that community-level treatment and control of schistosomiasis in areas where the infection, protein-energy malnutrition, and anaemia are common are to be encouraged and are likely to improve child growth, appetite, physical fitness and activity levels and to decrease anaemia and symptoms of the infection, and (2) that further studies are needed to determine how much and by what means decreases in and treatment of schistosomal infection may improve nutritional status, cognitive and school performance and attendance, and work capacity and productivity in communities with different amounts of parasitism and malnutrition.
Mutational and functional analysis of theLeishmaniasurface metalloproteinase GP63: similarities to matrix metalloproteinases
Authors: McMaster W. R. , Morrison C. J. , Macdonald M. H. , Joshi P. B.
Published: June 2009

The major surface glycoprotein ofLeishmania, referred to as GP63, is a zinc metalloproteinase of 63000Mrpresent on promastigotes and amastigotes from diverse species ofLeishmania. GP63 shares several characteristics with the members of the matrix metalloproteinase family including degradation of at least one component of the extracellular matrix, location at the cell surface, requirement for Zn2+for proteinase activity and inhibition of the proteinase activity by chelating agents and α2–macroglobulin. Site-directed mutagenesis of the clonedL. major GP63genes was carried out to determine whether the proposed active site ofLeishmaniaGP63 was homologous to those of other zinc metalloproteinases. The codon encoding the catalytic glutamic acid was modified to encode an aspartic acid and when expressed in COS–7 cells the resulting mutant GP63 had no demonstrable proteinase activity compared to wild type GP63. GP63 was predicted to be synthesized as a precursor protein containing a pro region at the NH2–terminus of GP63 implicated to be involved with the regulation of proteinase activity. As with many other proteinases, including matrix metalloproteinases, these enzymes are synthesized as latent proteinases that require activation for full proteinase activity.L. majorrecombinant GP63 (rGP63) has been produced in the baculovirus expression system whererGP63 was secreted as a latent proteinase. To study the activation of baculovirusrGP63, purifiedrGP63 was incubated with the mercurial compound, HgCl2, at concentrations previously shown to result in activation of other latent matrix degrading metalloproteinases and resulted in a significant enhancement of GP63 proteinase activity. The similarity of GP63 to the family of matrix-degrading proteinases suggests that the proteinase activity of GP63 maybe involved with the pathology of lesion formation in the mammalian host and may also be involved with the promastigote life stage in the sandfly vector. To study the functional role of GP63 proteinase, mutant strains ofL. major, deficient in the expression of GP63, are currently being derived by targeted gene deletion. Using this strategy results have demonstrated the deletion of an entireL. major GP63locus, containing in total sixGP63genes. Strategies to delete the secondGP63gene locus are developed and will determine whether deletion of both loci results in viable promastigotes.L. majorstrains deficient in the expression of GP63 may then be used to address the function of GP63 glycoprotein in the life cycle ofLeishmania.
Glycosyl-phosphatidylinositol molecules of the parasite and the host
Authors: Ferguson M. A. J. , Brimacombe J. S. , Cottaz S. , Field R. A. , Güther L. S. , Homans S. W. , McConville M. J. , Mehlert A. , Milne K. G. , Ralton J. E. , Roy Y. A. , Schneider P. , Zitzmann N.
Published: June 2009

The glycosyl-phosphatidylinositol (GPI) protein-membrane anchors are ubiquitous among the eukaryotes. However, while mammalian cells typically express in the order of 100 thousand copies of GPI-anchor per cell, the parasitic protozoa, particularly the kinetoplastids, express up to 10–20 million copies of GPI-anchor and/or GPI-related glycolipids per cell. Thus GPI-family members dominate the cell surface molecular architecture of these organisms. In several cases, GPI-anchored proteins, such as the variant surface glycoprotein (VSG) of the African trypanosomes, or GPI-related glycolipids, such as the lipophosphoglycan (LPG) of the Leishmania, are known to be essential for parasite survival and infectivity. The highly elevated levels and specialised nature of GPI metabolism in the kinetoplastid parasites suggest that the GPI biosynthetic pathways might be good targets for the development of chemotherapeutic agents. This article introduces the range of GPI structures found in protozoan parasites, and their mammalian hosts, and discusses some aspects of GPI biosynthesis.
Inhibition by anti-malarial drugs of haemoglobin denaturation and iron release in acidified red blood cell lysates – a possible mechanism of their anti-malarial effect?
Authors: Gabay T. , Krugliak M. , Shalmiev G. , Ginsburg H.
Published: June 2009

Intraerythrocytic malaria parasites ingest the cytosol of their host cell and digest it inside their acid food vacuoles. Acidified (pH 4–5·5, 37 °C) human red blood cell lysates were used to simulate this process, measuring the denaturation of haemoglobin (Hb) and the release of iron, in the absence or presence of exogenous protease. Spontaneous Hb denaturation and appearance of non-heme iron were observed upon lysate acidification, their rates decreasing with increasing pH, and increasing in the presence of protease. Both processes were inhibited by the quinoline-containing anti-malarial drugs (QCDs) chloroquine, quinine, mefloquine and amodiaquine at concentrations well below those expected in the acidic food vacuole of the parasite. Spectrophotometric analysis indicated that chloroquine complexes with heme in acid-denatured haemoglobin. Other weak bases as well as verapamil and diltiazem, known to reverse the resistance of malarial parasites to chloroquine, were without efifect indicating that the action of QCDs is specific. Based on our previous results and the present report, we suggest that iron release in acidified lysates is mediated through the formation of ferryl (Fe(IV)) radicals. QCDs possibly complex with this radical, as they do with heme, and prevent its contact with an adjacent heme molecule which is required for ring opening and iron release. These results may suggest that one of the anti-malarial effects of QCDs is to deprive the parasite of an adequate iron supply. Addition of iron to cultures ofPlasmodium falciparumwas expected to circumvent the deprivation of iron and reduce the anti-malarial eflfect of QCDs. However, adding iron as penetrating fructose or nitrilotriacetate complexes did not alter the parasite's susceptibility to chloroquine. Ascorbate markedly increased the release of iron in acidified lysates, and this effect was not reduced by chloroquine. Ascorbate was found to decrease parasite susceptibility to chloroquine, suggesting that iron deprivation may be an important factor in the anti-malarial action of QCDs.
Sarcocysts (Sarcocystis sp.: Sporozoa) in the European badger, Meles meles
Authors: Odening K. , Stolte M. , Walter G. , Bockhardt I. , Jakob W.
Published: June 2009

Sarcocysts from the tongue muscle of a European badger (Meles meles) are reported for the first time and described by light and transmission electron microscopy. Judging from the ultrastructure of the cyst wall, the parasite is similar to the species Sarcocystis gracilis Rátz, 1909 sensu Erber, Boch & Barth (1978) from roe deer and possibly identical with it. This is noteworthy regarding the intermediate host specificity.
Temporal changes in Trichuris trichiura infection intensity and serum isotype responses in children
Authors: Needham C. S. , Lillywhite J. E. , Didier J. M. , Bianco A. E. , Bundy D. A. P.
Published: June 2009

The present study describes Trichuris trichiura infections in a cohort of children over a period of approximately 5 years, and examines the relationships between changes in infection intensity and changes in parasite-specific isotype responses (measured by ELISA). The decrease in mean infection intensity with time was mirrored by time-dependent changes in IgG subclass responses, with IgA and IgE levels remaining relatively constant in the cohort. At the individual level, changes in infection intensity between the initial and final time-points correlated positively and significantly with changes in all isotype levels with the exception of IgA.
Developmentin vitroof free-living infective larvae to the parasitic stage ofStrongyloides venezuelensisby temperature shift
Authors: Tsuji N. , Fujisaki K.
Published: June 2009

Free-living infective larvaeStrongyloides venezuelensiswere cultured in Dulbecco's modified Eagle's medium at 25 and 37 °C, and development to the parasitic stage was evaluated using morphological, protein and antigenicity criteria. Few larvae cultured at 25 °C showed development whereas, in most of the larvae cultured at 37 °C, there appeared characteristic changes such as a bulb-like head and droplets under the cuticle with an increase of body width of the larvae. The results obtained from two-dimensional polyacrylamide gel electrophoresis(2D–PAGE) revealed that the protein spot patterns of the larvae cultured at 25 and 37 °C were differentiated by 17 specific spots. In addition, Western blot analysis combined with 2D–PAGE for reaction with serum obtained from an infected rat revealed that protein spots showing immunodominant antigen at 37 °C were almost the same as those of the larvae recovered from the rats rather than those of the larvae at 25 °C. These results strongly suggested that a temperature shift from 25 to 37 °C has an important role in the development of free-living infective larvae to the parasitic stage ofS. venezuelensis. The culture system established in the present study was useful for biological and biochemical studies in the development from/of the free-living to the parasitic stage ofStrongyloidesspecies.
Induction of the prophenoloxidase-activating system of Simulium (Diptera: Simuliidae) following Onchocerca (Nematoda: Filarioidea) infection
Authors: Hagen H.-E. , Grunewald J. , Ham P. J.
Published: June 2009

Trials were carried out to study the humoral immune response of blackflies to filariae following infection using the intrathoracic injection technique. An induced 66 kDa protein was abundant in the haemolymph of the European species Simulium ornatum following infection with bovine Onchocerca lienalis. This protein was apparently at higher concentrations in the haemolymph of sham-inoculated flies, i.e. flies that received sterile medium without the parasites. A molecule of the same size was also observed in the haemolymph of infected S. damnosum s.l. following infection with human O. volvulus or bovine O. ochengi. However, the level of this protein was lower in blackflies injected with microfilariae of bovine O. dukei. Unlike O. volvulus and O. ochengi this species is not transmitted by S. damnosum s.l. under natural conditions. No such reaction was observed if the African blackflies had received a sham inoculation. Feeding experiments with wild-caught nulliparous S. damnosum sl. on Onchocerca-infected cattle supported the results of the injection trials. The 66 kDa protein could only be found in the haemolymph of specimens infected via a blood meal. This 66 kDa molecule was identified as phenoloxidase. It appeared in the haemolymph due to the activation of the prophenoloxidase system following the filarial infection and we hypothesize that it may be sequestered by the parasites, as part of a non-self recognition system.
Endogenous superoxide dismutase activity in two Babesia species
Authors: Becuwe P. , Slomianny C. , Valentin A. , Schrevel J. , Camus D. , Dive D.
Published: June 2009

Parasitology, 105, 177–182

page 180:

The picture used for Fig. 2 represents isoelectrofocusing of B. divergens lysates.

The picture used for Fig. 3 represents isoelectrofocusing of B. hylomysci lysates.
Addendum
Authors: Petkevicius S. , Bjørn H. , Roepstorff A. , Nansen P. , Knudsen K. E. Bach , Barnes E. H. , Jensen K.
Published: June 2009

The effect of two types of diet on populations of Ascaris suum and Oesophagostomum dentatum in experimentally infected pigs Parasitology (1995), 111, 395–402

Part of the reference list that was omitted from p. 402 appears below.
Further additions to the British records of acephaline gregarines of earthworms
Authors: Segun A. O.
Published: June 2009

Five species of acephaline gregarine parasites – Apolocystis pilosa Meier from Lumbricus castaneus, L. festivus, L. rubellus and L. terrestris, Monocystis arcuata Boldt from L. castaneus, Nematocystis gracilis Berlin (= N. anguillula var. gracilis) from L. castaneus and L. rubellus, Zygocystis cometa Stein from Allolobophora caliginosa and Z. eiseniae Loubatieres from Eisenia foetida – identified during the present work are new to the British record.

The characteristics of two other monocystids, N. lumbricoides Hesse and N. lumbricoides var. pilosa Meier are identical apart from the presence of short ectoplasmic hairs on the latter trophozoite's body. Since the presence of ectoplasmic hairs which are projections on the trophozoite's body is often utilized in gregarine speciation, the hairy and the hairless monocystids should be described separately.

Berlin (1924) identified N. anguillula var. gracilis from the seminal vesicles of Lumbricus terrestris, L. rubellus and L. castaneus. This trophozoite should have been described as a separate species, N. gracilis Berlin and not as a variety of a totally different species originally described by Hesse (1909) from a host, Pheretima rodericensis, a megascolecid oligochaete, not found in Europe.

The writer wishes to express his sincere appreciation to Dr Anne Terry for her advice and useful suggestions, and to Mr D. Etherington, the head of department, for his encouragements throughout this research period.
Detection and species identification ofCryptosporidiumoocysts using a system based on PCR and endonuclease restriction
Authors: Awad-El-Kariem F. M. , Warhurst D. C. , McDonald V.
Published: June 2009

The polymerase chain reaction (PCR) was used to produce a 556 bp nucleotide stretch, employing primers based on the published sequence of the 18S rRNA genes inCryptosporidium parvumandC. muris. This sequence was found to contain 3MaeI endonuclease restriction sites, 1 of which was present only inC. parvum. Mae I restriction of PCR products from 2C.parvumisolates (one of human origin and the other of bovine origin), 1C. murisisolate, and 1C. baileyiisolate, showed a specific and reproducible profile forC. parvumthat was different from the one obtained for bothC. murisandC. baileyi. From these data, newMaeI restriction maps were proposed for the three species. The system was then used to screen 6C. parvumisolates (from human and bovine hosts), and theC. parvum-specific profile was obtained for all isolates examined. It should be possible to adapt this protocol to detect small numbers ofC. parvumoocysts in environmental samples (e.g. in water supplies).
The effect of Trichinella spiralis and Trichinella pseudospiralis on the mechanical properties of mammalian diaphragm muscle
Authors: Winter M. D. , Ball M. L. , Altringham J. D. , Lee D. L.
Published: June 2009

The isometric mechanical properties of diaphragm muscle were studied in mice infected with either Trichinella spiralis or Trichinella pseudospiralis. Measurements of muscle stress were taken at 15, 20, 30 and 40 days post-infection. Infected diaphragm muscle showed a significant (P < 0·001) reduction in muscle stress during both twitch and tetanic contractions when compared with muscle from control animals. T. spiralis caused a significant reduction in resistance to muscle fatigue. The consequences of these changes in muscle function to host pathology are discussed, and related to previous work on the effects of Trichinella on host biochemistry and the immune response.
Hydrogen peroxide is the most toxic oxygen species forOnchocerca cervicalismicrofilariae
Authors: Callahan H. L. , Chouch R. K. , James E. R.
Published: June 2009

The toxicity of the active oxygen species hydrogen peroxide, superoxide radical, hydroxyl radical and singlet oxygen to microfilariae (mf) has been studiedin vitro, using active oxygen-generating systems and scavengers/inhibitors. Mf viability was monitored by uptake of the radiolabel, [3H]2-deoxy-D-glouse. Hydrogen peroxide and singlet oxygen, but not superoxide radical or hydroxyl radical, are toxic for mf. Hydrogen peroxide was toxic for mf within 2 h at concentrations as low as 5 ¼, an amount eosinophils have been shown to releasein vitro(Weisset al.1986). Catalase and thiourea, but not inactivated catalase, superoxide dismutase (SOD), singlet oxygen scavengers, or hydroxyl radical scavengers, protected mf. Mf have relatively high levels of endogenous SOD but no measurable glutathione peroxidase and low levels of catalase when compared with other parasites (Callahan, Crouch & James, 1988). The low levels of hydrogen peroxide-scavenging enzymes correlate well with mf sensitivity to hydrogen peroxide and the protective effect of exogenous catalase.
A quantitative study of the susceptibility of cockroach species to Moniliformis moniliformis (Acanthocephala)
Authors: Moore J. , Crompton D. W. T.
Published: June 2009

We exposed 19 species of cockroaches to Moniliformis moniliformis by administering shelled acanthors orally and by injecting hatched acanthors directly into the body cavity. The exposure method had little influence on susceptibility: with one exception, species that were susceptible to oral exposure were also susceptible to injected acanthors and, in no case, did acanthors develop in injected animals when they did not develop in orally exposed conspecifics. We found no support for the hypothesis that the intestine may be a barrier to M. maniliformis establishment in cockroaches. There is, however, clear interspecific variation in susceptibility to M. moniliformis infection.
A positive correlation between population size and egg-content in Metastrongylus apri (Gmelin, 1790)
Authors: Dixon J. B.
Published: June 2009

Observations on the egg-content of 78 counted populations of Metastrongylus apri showed that there was a positive correlation between population size and mean egg-content per female. In bilateral infections within one host, a significant tendency was shown for the larger of the two populations to outstrip the smaller in mean egg-content per female. There was no correlation between sex-ratio and mean egg-content. It is suggested that the effect of the host's defences against individual parasites is mitigated when large numbers of parasites are present.

A positive correlation was found between the sex-ratios of populations in left and right lungs, and there was a significant predilection of M. apri for the right lung.

I am indebted to Dr S. Peto, Microbiological Research Establishment, Porton, Wilts, for statistical advice, and to T. Wall and Sons Ltd., Atlas Road, London, N.W. 10, for access to abattoir material.
Weight changes in chickens placed on different levels of nutrition and varying degrees of repeated dosage with Ascaridia galli eggs
Authors: Ikeme M. M.
Published: June 2009

The effect of continuing ingestion of eggs of A. galli on growth rates of chickens placed on different nutritional levels was studied under repeated doses of 10, 100 and 1000 infective eggs/day. With increasing amounts of protein in feed, there occurred significant weight differences between infected groups, the highest protein levels showing the longest duration in weight depression due to infection. On the other hand, assuming adequate nutrition of host, highest effects on growth rates were seen in chickens receiving daily doses of 1000 eggs daily and the lowest in chickens receiving 10 eggs daily.

The effect of repeated dose on growth rate is similar to the effect of single infections reported by previous workers except that the duration of the growth depression was much longer in the former due to pathogenic effects of inhibited larvae.

The author is indebted to the Department of Technical Cooperation, under whose Fellowship this study was carried out; to the Department of Zoology, Edinburgh University, where the work was done; to the Ministry of Agriculture, Fisheries and Food; Poultry Research Laboratories, Lasswade, for the free supply of chickens used here; and finally to Dr J. A. Campbell of Edinburgh University for his keen interest and advice throughout this work.
The chemical composition and some properties of the egg layers in Hymenolepis diminuta eggs
Authors: Lethbridge R. C.
Published: June 2009

1. It has been shown that the protein eggshell of Hymenolepis diminuta eggs was not significantly stabilized by sulphur or electrovalent linkages but was resistant to attack by proteolytic enzymes. Amino acid analysis demonstrated a marked preponderance of aromatic and heterocyclic acids and it has been suggested that these groups act as cross-linking agents in the shell protein.

2. The role of the lipid-containing subshell ‘membrane’ in protecting the enclosed embryo against fluctuations in pH and osmolarity in the external environment and infiltration of enzymes and toxic compounds has been demonstrated.

3. The cytoplasmic layer was shown to consist of a glucosamine-containing mucoprotein present in a dehydrated or semi-dehydrated state in the intact egg.In mechanically damaged eggs the cytoplasmic layer was rapidly dispersed by some proteolytic enzymes.

4. The embryophore enclosing the hexacanth embryo was composed of a sulphurrich protein that was weakened by some proteolytic enzymes and completely destroyed by others.

I should like to thank Professor T. R. E. Southwood, in whose department this work was carried out, and Dr June Mahon for her advice and encouragement.I am particularly grateful to Dr R. A. Wilson, Department of Biology, University of York, for the quantitative amino acid determinations on eggshell hydrolysates and for criticizing this manuscript. This research was conducted during the tenure of a Science Research Council Studentship and formed part of a thesis submitted for the Ph.D. degree, University of London.
Antigenic variation in Babesia rodhaini demonstrated by immunization with irradiated parasites
Authors: Phillips R. S.
Published: June 2009

1 Populations of Babesia rodhaini were isolated which were ‘putative’ variants of a reference population.

2. They were shown to have some antigenic dissimilarity to the reference population by comparing the response of rats immunized with irradiated parasites of the reference population, to challenge with either the reference population or with the variant populations. To the homologous challenge the immunized rats were strongly resistant. After a heterologous challenge, however, for the first 3 or 4 days the immunized rats showed no resistance but thereafter rapidly controlled the infection.

3. Five ‘variation’ populations were tested and all were shown to have some antigenic dissimilarity to the reference population. Two variant populations were compared and were not found to be identical with each other. There appeared, however, to be less dissimilarity between them and any one variant and the reference population.

Mrs J. Page and her successor Miss D. Leader, gave technical assistance. I thank my colleagues for helpful criticism of the manuscript.
Carbohydrate/lectin interactions between the nematophagous fungus,Arthrobotrys oligospora, and the infective juveniles ofTrichostrongylus colubriformis(Nematoda)
Authors: Wharton D. A. , Murray D. S.
Published: June 2009

Removal of the sheath of the ensheathed infective juvenile ofTrichostrongylus colubriformisprevents capture by the nematophagous fungusArthrobotrys oligospora. Exposure of the trap hyphae to a variety of saccharides, which may block a recognition system based on lectin/carbohydrate binding, failed to prevent capture but some saccharides did inhibit penetration and invasion by the fungus. Capture and penetration thus appear to be two distinct processes with capture being less specific than penetration. Carbohydrate residues were absent from the outer surface of the cuticle and the sheath but were present on the inner surface of the sheath. The limited accessibility of these lectin-binding sites may explain the slow process of infection of the infective juvenile by the fungus. The sheath does not protect the infective juvenile against attack by this nematophagous fungus.
Beta-oxidation in the free-living stages of the entomophilic nematodeRomanomermis culicivorax
Authors: Gordon R. , Walsh D. J. , Burford I. R.
Published: June 2009

All of the enzymes involved in the β-oxidation pathway were identified from juvenile and adult postparasites of the mermithid nematodeRomanomermis culicivorax. The postparasites readily took up exogenous [14C-U]palmitate and oxidized it to CO2, indicating that the β-oxidation pathway is functional. The extent to which this pathway is utilized during the natural cycle of the nematode is discussed.
Host protective humoral immune responses to Schistosoma mansoni infections in the rat. Kinetics of hyperimmune serum-dependent sensitivity and elimination of schistosomes in a passive transfer system
Authors: Mangold Beverley L. , Knopf P. M.
Published: June 2009

A passive transfer system, dependent upon hyperimmune rat serum, was used to study in vivo protective humoral immunity to Schistosoma mansoni infection in Fischer rats. Infected recipients of hyperimmune serum exhibited a significant reduction (51%) in the number of recovered adult schistosomes relative to infected recipients of normal rat serum. Furthermore, schistosomula were equally sensitive to the effects of hyperimmune serum injected up to and including 7 days post-infection, a phenomenon which was termed ‘extended sensitivity’. Schistosomula were beginning to lose sensitivity to the effects of hyperimmune serum by the 8th day post-infection and were completely refractile by the 9th day. In addition, it was demonstrated that parasite elimination occurred after the lung stage. Some protection was also observed when hyperimmune rat serum was transferred to mice as late as 5 days post-infection.
Cercaria vaullegeardi Pelseneer, 1906 (Digenea: Hemiuridae); development and ultrastructure
Authors: Matthews B. F.
Published: June 2009

Cercaria vaullegeardi develops in daughter sporocysts within the digestive gland of the prosobranch Gibbula umbilicalis. On emergence into the host mantle cavity the cercarial body retracts into the cystophorous tail, the ‘encysted’ cercaria being then shed into the sea. The encysted cercaria is described at the ultrastructural level for the first time and developmental stages are redescribed. The cercarial body has no penetration or cystogenous glands: a single type of sub-tegumental secretory cell produces vesicles containing neutral mucopolysaccharides which pass into the tegument at encystment. The immotile cystophorous tail consists essentially of a fibrous caudal cyst and 8 appendages including a delivery tube. Scanning electron micrographs show the surface of tegumental membranes enveloping the caudal cyst to be covered with a honeycomb pattern of indentations derived from electron-lucent vesicles produced by the caudal gland. The fibrous-walled delivery tube comprises proximal and distal sections and a modified terminal end-piece.
A statistical approach to schistosome population dynamics and estimation of the life-span of Schistosoma mansoni in man
Authors: Fulford A. J. C. , Butterworth A. E. , Ouma J. H. , Sturrock R. F.
Published: June 2009

Dynamic models which predict changes in the intensity of schistosome infection with host age are fitted to pre-intervention Schistosoma mansoni data from Kenya. Age-specific post-treatment-reinfection data are used to estimate the force of infection, thus enabling investigation of the rate of worm death. An empirical and statistical approach is taken to the model fitting: where possible, distributional properties and function relationships are obtained from the data rather than assumed from theory. Attempts are made to remove known sources of bias. Maximum likelihood techniques, employed to allow for error in both the pre-intervention and reinfection data, yield confidence intervals for the worm life-span (CI95% = 5·7–10·5 years) and demonstrate that the worm death rate is unlikely to vary with host age. The possibilities and limitations of fitting dynamic models to data are discussed. We conclude that a detailed, quantitative approach will be necessary if progress is to be made with the interpretation of epidemiological data and the models intended to describe them.
Errata
Authors: Wang H. , Nuttall P. A.
Published: June 2009

Comparison of the proteins in salivary glands, saliva and haemolymph of Rhipicephalus appendiculatus female ticks during feeding

Parasitology (1994), 109, 517–523

Fig. 2. Delete 24 kDa marker between 36 kDa and 29 kDa markers.

Fig. 6. Replace 24 to 17·6 kDa with 34, 33·5, 32·5, 31·5, 30, 29 kDa.

Fig. 7. Replace 33·2 kDa with 33·5 kDa.

Excretion of host immunoglobulin in tick saliva and detection of IgG-binding proteins in tick haemolymph and salivary glands

Parasitology (1994), 109, 525–530

Fig. 4. Replace 19·2 kDa with 14·2 kDa.
Influence of environmental factors on the infectivity ofEchinococcus multiloculariseggs
Authors: Veit P. , Bilger B. , Schad V. , Schäfer J. , Frank W. , Lucius R.
Published: June 2009

The sensitivity of eggs ofEchinococcus multilocularisto environmental and controlled laboratory conditions was tested. Egg material was exposed and the infectivity was subsequently monitored byin vitroactivation and by oral infection of the natural host,Microtus arvalis. To study the impact of environmental conditions in an endemic area of south-western Germany, eggs were sealed into bags of nylon mesh and exposed to the natural climate during various seasons. The maximal survival time of eggs was 240 days in an experiment performed in autumn and winter and 78 days in summer. A study of the tenacity of eggs under laboratory conditions revealed a high sensitivity to elevated temperatures and to desiccation. At 45 °C and 85–95% relative humidity the infectivity was lost after 3 h as well as after 4 h exposure to 43 °C suspended in water. Exposure to 27% relative humidity at 25 °C as well as exposure to 15% relative humidity at 43 °C resulted in a total loss of infectivity within 48 and 2 h, respectively. Temperatures of 4 °C and of –18 °C were well tolerated (478 days and 240 days survival, respectively), whereas exposure to –83 °C and to –196 °C quickly killed off the eggs (within 48 h and 20 h, respectively). Eggs ofE. multiloculariswere not killed off by exposure to various commercially available disinfectants applied according to the manufacturers' instructions and by exposure for 24 h to low concentrations of ethanol. Irradiation with 40 krad. from a137Caesium source prevented the development of metacestodes but allowed seroconversion of infected rodents.
Erratum
Authors: McNamara J. J. , Mohammed G. , Gibson W. C.
Published: June 2009

Trypanosoma (Nannomonas) godfreyi sp. nov. from tsetse flies in The Gambia: biological and biochemical characterization

Parasitology109, 497–511

p. 499, para. 2, 104/ml to replace 104/μl

p. 501, para. 1, chromsomes to replace chromosome

p. 501, para. 2, 1/148 to replace 1/48

p. 504, para. 3, BAN 9 or KEN 7 to replace BAN 9 & KEN 7