bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of an interferon inducer onEimeria maximain the chicken
Authors: Long P. L. , Milne B. S. 
Published: June 2009

The intraperitoneal inoculation of chickens with 100–170 mg of Statolon, an artificial interferon inducer in mammals, induced the production of a virus interference factor in the serum. Chickens, 3 and 5 weeks old given 40–170 mg Statolon i.p. produced significantly fewer oocysts after infection withE. maximathan untreated chickens.Only three serum samples (from a large number examined) taken from chickens 1, 4 or 6 days afterE. tenellainfection or 6 h and 6 days afterE. maximainfection showed slight but significant antiviral effects.
Theileria parva: Comparative infection rates of adult and nymphal Rhipicephalus appendiculatus
Authors: Purnell R. E. , Boarer C. D. H. , Peirce M. A. 
Published: June 2009

Sections of salivary glands from adult R. appendiculatus ticks and sections of the whole bodies of nymphal R. appendiculatus ticks were studied to obtain data on the incidence and development of T. parva during feeding. Since, in their previous instars, all the ticks had dropped engorged from a parasitaemic calf on the same day, it was possible to compare the resultant infection rates in nymphs and adults.In the adult ticks, the highest percentage infection (45%) and the greatest number of infected acini (45 from 20 ticks) were observed after 3 days feeding. Mature parasites were first seen after 4 days. In the nymphs, the highest percentage infection (35%) was observed after 3 days feeding. Equal numbers of infected acini (14 from 20 ticks) were observed in unfed nymphs and in those which had fed for 2 or 3 days. Mature parasites were first seen after 2 days, and all were mature after 3 days.It was concluded that a batch of nymphs would contain more parasites per gramme than a corresponding batch of adult ticks. This fact, together with the observed uniformity of maturation of the parasites in nymphs, may make nymphs a more suitable choice than adults for the preparation of ground tick stabilates.We are most grateful to Mr M. P. Cunningham, who inoculated the calf on which the ticks fed, and to Mr A. Musoke who observed the subsequent clinical reaction of the calf.This work was carried out as part of the programme of the Immunological Research on Tick-borne Cattle Diseases and Tick Control Project which is supported by the United Nations Development Programme/Special Fund, with F.A.O. as the Executing Agency, in collaboration with the East African Community. The assistance of our colleagues on the Project is gratefully acknowledged. This paper is published by kind permission of Mr A. Rashid, the Director of the East African Veterinary Research Organization.
Observations on the movement of fluids in the vicinity of the mouthparts of naturally feeding Dermacentor andersoni Stiles
Authors: Gregson J. D. 
Published: June 2009

Observations on the movement of fluids in the vicinity of the mouthparts of actively feeding female Dermacentor andersoni were made with the aid of trans-illuminated live-hamster pouch host-tissue. Following tick attachment and the invasion of ‘attaching cement’ into the outer skin layers, there appeared a progressive release of host blood as the tick settled into a feeding pattern. Short periods of sucking, each followed by an immediate ejaculation of saliva, became lengthened as feeding progressed, as did the resting intervals between sucking. Other movements brought about by the tick included a ‘toying’ of the tissue fluid, a rapid vibration of the same, and a distinct regurgitation of host-blood material. A sudden haemorrhage usually appeared at the feeding site about 2½ h after attachment of partially fed ticks.Speculations are made concerning the part played by the release of tick saliva and tick water loss, its probable relationship to host paralysis, and its apparent role in tick nourishment.
The cat flea, Ctenocephalides felis felis (Bouché, 1835) as an intermediate host for cestodes
Authors: Marshall Adrian G. 
Published: June 2009

The growth and development of Dipylidium caninum, Hymenolepis citelli, H. diminuta, H. microstoma, and H. nana were examined in Ctenocephalides felis, and the Hymenolepis species further examined in the reference host Tribolium confusum. This is the first recorded infection of C. felis with these four species of Hymenolepis and also of a flea with H. citelli.Growth and development of the four species of Hymenolepis were comparable in C. felis and T. confusum. Observations relative to scolex formation indicated that perhaps only one basic sequence occurs in the genus Hymenolepis.Growth and metamorphosis of the flea host had no important effects upon Hymenolepis development. However, presumably owing to greater crowding in C. felis than in T. confusum, an increased amount of retarded development was noted in cestodes from fleas. In contrast, the growth and metamorphosis of the flea host did affect the development of D. caninum. Little growth occurred in larval fleas but with the onset of pupation an increased growth rate was initiated, the cestode reaching almost its maximum size prior to the emergence of the adult flea. Cysticercoid differentiation and maturation mostly occurred within the adult.
Monocystid gregarines of Nigerian earthworms. I. Adelphocystis aeikineta gen.nov., sp.nov. from the coelom of Keffia variabilis Clausen, 1963
Authors: Cox F. E. G. 
Published: June 2009

Adelphocystis aeikineta, a new species of monocystid gregarine, is found in the coelom of the earthworm Keffia variabilis in which the trophozoites occur in large numbers in permanently associated pairs. They are large, measuring 750–1500, μm in length, and exhibit continual peristaltic motion. The ectosarc of the trophozoite is markedly striated and there is no evidence of any anterior differentiation. The gametocytes are rounded and the presumed bipolar sporocysts measure 12–14·5 μm in length. Some associated pairs occur in groups enclosed in a membrane and there is evidence that gametocytes may form under these conditions. A. aeikineta is placed in the subfamily Zygocystinae and separated from Zygocystis on its elongate shape. The site of infection of this gregarine, and others recently described, suggests that the morphological basis on which the family Monocystidae is divided into subfamilies and genera is inadequate and a sounder classification should take into account these sites of infection.The material on which this paper is based was collected while I was in receipt of a Wellcome Trust Travelling Grant, and I wish to thank the Trust for this support. It is also a pleasure to thank Mr R. W. Sims of the British Museum (Natural History) who identified the earthworms, Dr Keith Vickerman who helped me to collect them and Mr R. B. Freeman who advised me on the nomenclature.
The evolution of inducible defence
Authors: Harvell C. D. 
Published: June 2009

SummaryDefences 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

SummaryThe 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

SummaryWhy 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

SUMMARYBabesia 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

SUMMARYThe 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

SUMMARYAerobic 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

SUMMARYSubstance 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

SUMMARYHomologues 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

SUMMARYThere 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

SUMMARYGiardia 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.