Parasitology
1469-8161
0031-1820
Anh Quốc
Cơ quản chủ quản: CAMBRIDGE UNIV PRESS , Cambridge University Press
Lĩnh vực:
Animal Science and ZoologyInfectious DiseasesParasitology
Các bài báo tiêu biểu
A new species of trypanosome, <i>Trypanosoma desterrensis</i> sp. n., isolated from South American bats Trypanosomes isolated from South American bats include the human pathogen Trypanosoma cruzi . Other Trypanosoma spp. that have been found exclusively in bats are not well characterized at the DNA sequence level and we have therefore used the SL RNA gene to differentiate and characterize kinetoplastids isolated from bats in South America. A Trypanosoma sp. isolated from bats in southern Brazil was compared with the geographically diverse isolates T. cruzi marinkellei , T. vespertilionis , and T. dionisii . Analysis of the SL RNA gene repeats revealed size and sequence variability among these bat trypanosomes. We have developed hybridization probes to separate these bat isolates and have analysed the DNA sequence data to estimate their relatedness. A new species, Trypanosoma desterrensis sp. n., is proposed, for which a 5S rRNA gene was also found within the SL RNA repeat.
Tập 127 Số 3 - Trang 265-271 - 2003
Phylogeny of snake trypanosomes inferred by SSU rDNA sequences, their possible transmission by phlebotomines, and taxonomic appraisal by molecular, cross-infection and morphological analysis SUMMARY Blood examination by microhaematocrit and haemoculture of 459 snakes belonging to 37 species revealed 2·4% trypanosome prevalence in species of Viperidae (Crotalus durissus andBothrops jararaca ) and Colubridae (Pseudoboa nigra ). Trypanosome cultures fromC. durissus andP. nigra were behaviourally and morphologically indistinguishable. In addition, the growth and morphological features of a trypanosome from the sand flyViannamyia tuberculata were similar to those of snake isolates. Cross-infection experiments revealed a lack of host restriction, as snakes of 3 species were infected with the trypanosome fromC. durissus . Phylogeny based on ribosomal sequences revealed that snake trypanosomes clustered together with the sand fly trypanosome, forming a new phylogenetic lineage withinTrypanosoma closest to a clade of lizard trypanosomes transmitted by sand flies†. The clade of trypanosomes from snakes and lizards suggests an association between the evolutionary histories of these trypanosomes and their squamate hosts. Moreover, data strongly indicated that these trypanosomes are transmitted by sand flies. The flaws of the current taxonomy of snake trypanosomes are discussed, and the need for molecular parameters to be adopted is emphasized. To our knowledge, this is the first molecular phylogenetic study of snake trypanosomes.
Tập 135 Số 5 - Trang 595-605 - 2008
Habitat fragmentation and haemoparasites in the common fruit bat,<i>Artibeus jamaicensis</i>(Phyllostomidae) in a tropical lowland forest in Panamá SUMMARY Anthropogenic influence on ecosystems, such as habitat fragmentation, impacts species diversity and interactions. There is growing evidence that degradation of habitats favours disease and hence affects ecosystem health. The prevalence of haemoparasites in the Common Fruit Bat (Artibeus jamaicensis ) in a tropical lowland forest in Panamá was studied. We assessed the relation of haemoparasite to the general condition of the animals and tested for possible association of haemoparasite prevalence to habitat fragmentation, with special focus on trypanosomes. Overall, a total of 250A. jamaicensis sampled from fragmented sites, here man-made, forested islands in Lake Gatùn, and sites in the adjacent, continuous forest in and around the Barro Colorado Nature Monument were examined. Using microscopy and DNA-sequencing 2 dominant types of haemoparasite infections, trypanosomes andLitomosoides (Nematoda) were identified. Trypanosome prevalence was significantly higher in bats from forest fragments, than in bats captured in continuous forest. We attribute this to the loss of species richness in forest fragments and specific characteristics of the fragments favouring trypanosome transmission, in particular changes in vegetation cover. Interestingly, the effect of habitat fragmentation on the prevalence of trypanosomes as multi-host parasites could not be observed inLitomosoides which probably has a higher host specificity and might be affected less by overall diversity loss.
Tập 136 Số 10 - Trang 1133-1145 - 2009
An Experimental Study of the Sheep-Trypanosome (<i>T. melophagium</i> Flu, 1908), and its Transmission by the Sheep-Ked (<i>Melophagus ovinus</i> L.) Trypanosoma melophagium Flu, 1908, is a parasite of European domestic sheep (Ovis aries L.), in the blood of which it occurs in very scanty numbers and can be detected by the cultural method. In England it has been found in 80 per cent, of sheep examined.The infection is of fairly short duration and does not produce an immunity in sheep, since the latter can easily be re-infected. In all probability T. melophagium produces no pathological effect in sheep, and is incapable of infecting laboratory animals. Morphologically the sheep-trypanosome is closely allied to the cattle-trypanosome, T. theileri . The intermediate host of T. melophagium is the sheep-ked, Melophagus ovinus L., in the alimentary canal of which it passes through a definite cycle of development ending in the production of infective forms (metacyclic trypanosomes) in the hind-gut of the insect. The mode of transmission is contammative, the sheep acquiring an infection by ingesting the ked. Infection of sheep did not result from the bite of the ked, through abrasions of the skin, or from inoculation of cultures of the trypanosome. T. melophagium is easily cultivated at 30° C. Its evolution in cultures is similar to that in the invertebrate host.
Tập 15 Số 4 - Trang 365-424 - 1923
Identification and characterization of cross-reactive antigens from Neospora caninum and Toxoplasma gondii
Tập 130 Số 5 - Trang 481-488 - 2005
Control options for<i>Neospora caninum</i>– is there anything new or are we going backwards? SUMMARY Recent work has highlighted and enumerated the economic annual losses due toNeospora caninum abortions worldwide, which should provide strong motivation for the control of bovine neosporosis. However, with the recent withdrawal from sale of the only commercially available vaccine, control options forN. caninum have become more restricted. While researchers continue to work on developing alternative efficacious vaccines, what are the control options presently available for the cattle industries? At the practical level, recommendations for ‘Test-and-cull’, or ‘not breeding from seropositive dams’ stand diametrically opposed to alternative options put forward that suggest a primary producer is better advised to keep those cows in the herd that are already seropositive, i.e. assumed to be chronically infected, and indeed those that have already aborted once. Treatment with a coccidiostat has been recommended as the only economically viable option, yet no such treatment has gained official, regulatory approval. Dogs are central to the life cycle ofN. caninum and have repeatedly been associated with infection and abortions in cattle by epidemiological studies. Knowledge and understanding of that pivotal role should be able to be put to use in control programmes. The present review canvasses the relevant literature for evidence for control options forN. caninum (some of them proven, many not) and assesses them in the light of the authors’ knowledge and experience with control ofN. caninum .
Tập 141 Số 11 - Trang 1455-1470 - 2014
Specificity of carbohydrate transport in<i>Trypanosoma equiperdum</i> Trypanosoma equiperdum was found to take up glucose, mannose, fructose and glycerol but not galactose. Data with inhibitors suggested that the absorption of these compounds occurred by mediated processes. The inhibitory activity of various compounds indicated that three separate sites were involved in transport, two for glycerol and one for the hexoses.
Tập 68 Số 2 - Trang 103-115 - 1974
Notes on certain points in the Cytology Of <i>Trypanosoma raiae</i> and <i>Bodo caudatus</i> 1. T. raiae and Bodo caudatus are investigated using Feulgen's nucleal reaction in addition to the usual nuclear stains. The nature and value of this method is discussed. 2. In T. raiae the parabasal body or kinetonucleus is found to consist of chromatin as shown by the nucleal reaction. An achromatic element in its composition is suggested in the division by the desmose between the two halves being achromatic. The blepharoplast is an achromatic structure. It seems probable that it persists in the aflagellar phase of the trypanosome. In T. raiae the division of the blepharoplast precedes but does not apparently orientate the division of the parabasal body. The division of the parabasal body does not present a mitotic figure. 3. The nucleus in T. raiae consists of an achromatic karyosome body with some chromatin surrounding it, there is also chromatin arranged upon the inner surface of the nuclear membrane. 4. At division the karyosome apparently draws out into an achromatic spindle figure, the chromatin collects in the prophase into a loose granular mass and then becomes arranged at the equator. The mass divides into two portions; it is not possible to distinguish chromosomes with sufficient certainty. The nuclei are finally reconstructed from the achromatic ends of the spindle and the chromatin which has travelled to either pole. 5. In Bodo caudatus the parabasal body (kinetonucleus) is composed of chromatin and of an achromatic substance, the blepharoplasts or basal granules are achromatic bodies which play an orientating part in the division of the parabasal body: this division does not show an equatorial plate stage. The nucleus is made up of an achromatic nucleolus-karyosome surrounded by a hollow sphere of chromatin; there is a very definite division process which takes place apparently within the nuclear space. There is no equatorial plate formed and the achromatic figure which is derived directly from the karyosome is a division column which inserts itself into the already dividing chromatin and is not of the spindle fibre type found in the mitosis of the metazoan cell and of many protozoa .
Tập 19 Số 4 - Trang 375-393 - 1927
Scanning for nucleotide variations in mitochondrial DNA fragments of <i>Schistosoma japonicum</i> by single-strand conformation polymorphism In this study, we employed a mutation scanning approach for the
direct visual display of genetic variability in mitochondrial
DNA (mtDNA) fragments within and among populations of Schistosoma japonicum
from the People's Republic of
China. Fragments of the NADH dehydrogenase 1 gene (ND1) and the cytochrome
c oxidase subunit I (COI) were
individually amplified from parasite DNA by polymerase chain reaction (PCR),
denatured and subjected to single-strand
conformation polymorphism (SSCP) analysis. Using ND1 and COI fragments,
individuals representing different genotypes
could be readily identified based on characteristic and reproducible SSCP
profiles. The results demonstrated the
usefulness of SSCP for the direct visual display of low-level sequence
variation in mtDNA of S. japonicum prior to DNA
sequence analysis. This approach has important implications for studying
the genetic structure and biology of S. japonicum
populations, and for analysing the inheritance of mitochondrial DNA.
Tập 118 Số 1 - Trang 73-82 - 1999
Programmed cell death in African trypanosomes Until recently it had generally been assumed that apoptosis and other forms of programmed cell death evolved during evolution of the metazoans to regulate growth and development in these multicellular organisms. However, recent research is adding strength to the original phenotypic observations described almost a decade ago which indicated that some parasitic protozoa may have evolved a cell death pathway analogous to the process described as apoptosis in metazoa. Here we explore the implications of a programmed cell death pathway in the African tsetse-transmitted trypanosomes.
Tập 132 Số S1 - Trang S7-S18 - 2006