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At least 19 recordsLinked to original sources
PubMed2003

Phylogenetic analysis of the Metastrongyloidea (Nematoda: Strongylida) inferred from ribosomal RNA gene sequences.

Phylogenetic relationships among nematodes of the strongylid superfamily Metastrongyloidea were analyzed using partial sequences from the large-subunit ribosomal RNA (LSU rRNA) and small-subunit ribosomal RNA (SSU rRNA) genes. Regions of nuclear ribosomal DNA (rDNA) were amplified by polymerase chain reaction, directly sequenced, aligned, and phylogenies inferred using maximum parsimony. Phylogenetic hypotheses inferred from the SSU rRNA gene supported the monophyly of representative taxa from each of the 7 currently accepted metastrongyloid families. Metastrongyloid taxa formed the sister group to representative trichostrongyloid sequences based on SSU data. Sequences from either the SSU or LSU RNA regions alone provided poor resolution for relationships within the Metastrongyloidea. However, a combined analysis using sequences from all rDNA regions yielded 3 equally parsimonious trees that represented the abursate Filaroididae as polyphyletic, Parafilaroides decorus as the sister species to the monophyletic Pseudaliidae, and a sister group relationship between Oslerus osleri and Metastrongylus salmi. Relationships among 3 members of the Crenosomatidae, and 1 representative of the Skrjabingylidae (Skrjabingylus chitwoodorum) were not resolved by these combined data. However, members of both these groups were consistently resolved as the sister group to the other metastrongyloid families. These relationships are inconsistent with traditional classifications of the Metastrongyloidea and existing hypotheses for their evolution.

Animals↗
PubMed1984

Humoral immunity and output of first-stage larvae of Elaphostrongylus rangiferi (Nematoda, Metastrongyloidea) by infected reindeer, Rangifer tarandus tarandus.

The use of an indirect immunofluorescence technique demonstrated that serum from reindeer, Rangifer tarandus tarandus, infected with Elaphostrongylus rangiferi (Nematoda, Metastrongyloidea) contained antibodies directed against antigen(s) on the cuticle of the parasites first-stage larvae (L1). Output of L1 from the male reindeer was low in the period June to August, but increased to a higher level during the rutting season (September to October). The titre of specific antibody showed an inverse pattern. In the female reindeer, larval output remained high throughout the sampling period from January to July. During this period antibody titre was low. A relationship between stress (rutting season or calving period), immunity and larval output is suggested.

Animals↗
PubMed1999

Evolutionary relationships among the protostrongylidae (Nematoda: Metastrongyloidea) as inferred from morphological characters, with consideration of parasite-host coevolution.

The phylogeny of nematodes in the family Protostrongylidae (Nematoda: Metastrongyloidea) was reconstructed by cladistic analysis of 28 binary and multistate characters derived from comparative morphology. Analyses were hierarchical, and examined (1) relationships among genera, including 13 ingroup taxa and Metastrongylidae as an outgroup (single tree, 78 steps, consistency index [CI] = 0.705); and (2) relationships among genera and species groups, including 21 ingroup taxa and Metastrongylus apri as an outgroup (single tree, 76 steps, CI = 0.582). In the species-level tree, Protostrongylidae was divided into 2 major clades, 1 containing the subfamilies Muelleriinae (including the recently described Umingmtakstrangylus pallikuukensis), Elaphostrongylinae, and the Varestrongylinae (excluding Pneumocaulus kadenazii). Varestrongylus was paraphyletic as it included Pneumostrongylus calcaratus. The second major clade consisted of a paraphyletic group containing Protostrongylus spp. and Spiculocaulus leuckarti and, basal to this subclade, several other individual protostrongylid lineages. The various subclades generally correspond to the subfamilial divisions of the Protostrongylidae. The Neostrongylinae, however, is not supported as Neostrongylus and Orthostrongylus are not sister groups. Based on a large number of hypothesized synapomorphies, the elaphostrongylines appear to be a highly derived group of protostrongylids, a feature potentially correlated with their habitat localization in muscular and nervous tissues. The generic-level tree retained most of the primary structure revealed among the species but excluded the varestrongylines from the Muelleriinae + Elaphostrongylinae subclade. Artiodactyles of the family Cervidae are considered basal hosts for protostrongylids; secondary colonization in Caprini, Rupicaprini, and among lagomorphs is postulated.

Animals↗
PubMed1984

Moisture and temperature effects on survival and infectivity of first-stage larvae of Parelaphostrongylus odocoilei and P. tenuis (Nematoda: Metastrongyloidea).

The survival of first-stage larvae (L1) of Parelaphostrongylus odocoilei and P. tenuis (Nematoda: Metastrongyloidea) and their infectivity to the snail Triodopsis multilineata were determined experimentally in a variety of temperature and moisture conditions. Survival of larvae of P. odocoilei increased with decreasing temperature. Survival of larvae in water was similar to survival in air at 17 and 45% RH; survival of larvae in air at 75, 85, and 95% RH was considerably lower at corresponding temperatures. The infectivity of larvae of P. odocoilei that survived desiccation was greatly reduced. Repeated freezing or repeated desiccation resulted in reduced survival of P. odocoilei and P. tenuis. Larvae of Parelaphostrongylus odocoilei from mule deer of Jasper National Park, Canada, were better able to resist the effects of freezing, but less able to resist the effects of desiccation, than were larvae of P. tenuis from white-tailed deer of Pennsylvania, USA.

Animals↗
PubMed2004

Seasonal dynamics of the fecal excretion of Elaphostrongylus cervi (Nematoda, Metastrongyloidea) first-stage larvae in Iberian red deer (Cervus elaphus hispanicus) from southern Spain.

Elaphostrongylus cervi (Nematoda, Metastrongyloidea) is an extrapulmonary lungworm of red deer (Cervus elaphus) whose first-stage larvae (L1) require terrestrial gastropods as intermediate hosts. The seasonal pattern of fecal excretion of E. cervi L1 in Iberian red deer (Cervus elaphus hispanicus) was monitored during three annual periods (June 2000-May 2003) on a hunting estate from south-central Spain. The lowest rates of mean intensity of fecal L1 were found in summer, whereas no seasonal variation was found for prevalence. Monthly intensity of excretion was positively associated with early rainfall (the next month) rather than with rainfall of the same month. This seasonal rhythm of E. cervi L1 discharge may be the result of parasite adaptation to the seasonal Mediterranean climate and habitat constraints to improve the chance of parasite transmission. We have standardized the sampling period to compare E. cervi L1 infection rates of Iberian red deer populations in Mediterranean Spain, a natural limit of both the parasite and deer historical ranges, for potential use in the assessment of management strategies.

Animals↗
PubMed1996

The influence of aestivation in land snails on the larval development of Muellerius cf. capillaris (Metastrongyloidea: Protostrongylidae).

The larval development of Muellerius cf. capillaris in aestivating Trochoidea seetzenii and Theba pisana was delayed: in the first snail 82% of the parasites remained as second-stage larvae (L2) after as much as 90 days, and in the second snail 60% remained as L2 after 50 days. Reactivation of T. seetzenii after 59 days of aestivation caused the larvae to develop to the third stage (L3). The number of recovered larvae among T. seetzenii was consistently higher in active vs aestivating snails (P < 0.05). Such differences were not evident among T. pisana (P > 0.05). In active T. pisana, larval development was faster than in active T. seetzenii, whereas there were no such differences between aestivating snails of these 2 species. Aestivating infected T. seetzenii had lower body weights than same-size active non-infected, as well as infected snails. Aestivating infected T. pisana were not weighed, but they too exhibited poor body condition.

Analysis of Variance↗
PubMed1981

Pathways of purine ribonucleotide biosynthesis in the adult worm Metastrongylus apri (Nematoda: Metastrongyloidea) from pig lung.

The pathways of purine ribonucleotide synthesis and interconversion that are operative in the intact adult pig lung worm Metastrongylus apri were identified by radioisotope tracing. The rate of [14C]glycine incorporation into purines was low but sufficient to demonstrate synthesis de novo. Radioactively labelled adenine, hypoxanthine and guanine were readily taken up and converted to the corresponding mononucleotides. Most of the AMP and GMP formed were phosphorylated to the triphosphates. These two nucleotides were interconvertable by pathways in which IMP is an intermediate. Adenosine was converted to nucleotides by direct phosphorylation as well as via formation of hypoxanthine. The rate of synthesis of adenine nucleotides from hypoxanthine was 5-7 times that of guanine nucleotides; conversion of IMP to AMP and to xanthosine 5'-monophosphate were the rate-limiting steps.

Adenine Nucleotides↗
PubMed1979

De novo purine ribonucleotide biosynthesis in adult Angiostrongylus cantonensis (Nematoda: Metastrongyloidea).

1. Radioactivity was found to be associated with purine ribonucleotides in extracts of gravid adult Angiostrongylus cantonensis from the lungs of rats when the parasite was incubated in a medium containing [14C]glycine. 2. The rate of incorporation was at least 0.2 pmole/min per mg of parasite and approximately equal amounts of adenine and guanine ribonucleotides were synthesized. 3. This is the first demonstration of the capacity for a mammalian parasitic helminth to synthesize purines de novo.

Adenine↗
PubMed1990

Lipids of Angiostrongylus cantonensis (Nematoda: Metastrongyloidea): a comparison between young adults and gravid worms.

1. All major classes of lipids were found in the young adults in brain (22 days post-infection) and gravid Angiostrongylus cantonensis in lung of rats (34 days post-infection) comprising approximately 60% of phospholipids, 30% of neutral lipids and the rest, glycolipids. 2. The relative composition of phospholipids were quite similar between worms from the two different habitats, with phosphatidylcholine predominating. The glycolipid profiles were also similar. 3. More neutral lipids in the worms from brain existed as cholesterol and cholesterol esters than those from the lung. More than 20% of the fatty acids in these lipids of the brain were found as C10-C14 acids while oleic acid was the main component in the lung worm.

Aging↗
PubMed1999

Intraspecific and interspecific variation in the second internal transcribed spacer (ITS-2) sequence for Metastrongylus (Nematoda: Metastrongyloidea) detected by high resolution PCR-RFLP.

Metastrongylus species are important parasites of free-range pigs and wild boar, but little is known about the genetic make-up of natural populations. This study was undertaken to examine sequence variation in the internal transcribed spacer 2 of ribosomal DNA within and among three species of Metastrongylus using PCR-linked restriction fragment length polymorphism analysis. In contrast to many other species of bursate nematodes, significant intraspecific variation was detected in restriction fragment length polymorphism profiles among individual worms. In spite of this, it was possible to identify the three species by their distinctive restriction profiles. The findings suggest that the internal transcribed spacer 2 region should be useful for analysing population variation within Metastrongylus species.

Animals↗
PubMed2001

Mutation scanning analysis of microsatellite variability in the second internal transcribed spacer (precursor ribosomal RNA) for three species of Metastrongylus (Strongylida: Metastrongyloidea).

This study investigated sequence variability in the second internal transcribed spacer of ribosomal DNA for 3 species of Metastrongylus (porcine lungworms). The ITS-2 region was amplified by PCR from individuals of M. elongatus, M. pudendotectus and M. salmi, and then subjected directly to single-strand conformation polymorphism analysis (SSCP), which allowed the direct display of sequence variation within and among individuals representing each species. There were marked differences in SSCP profiles among species, making this approach useful for species identification. For individual species, representative bands were excised from electrophoretic gels, reamplified by PCR and subjected to direct sequencing. For all 3 taxa, variability in the ITS-2 was related chiefly to the presence of microsatellites. Eight different microsatellites were identified, namely (A)n, (TG)n, (TCG)n, (TA)n, (TATG)n, (G)n, (TACA)n and (T)n. Considerable variability in microsatellite repeat number (ranging from 1 to 23) was found among individual nematodes of a species and between species. The microsatellites were located to specific stem or loop regions in the predicted ITS-2 precursor rRNA secondary structure. The results may suggest that slipped-strand mispairing in microsatellite regions contributes to sequence variability in the ITS-2 of Metastrongylus species under structural constraint as a consequence of microsatellite location in the precursor rRNA. Similar studies of the ITS-2 for a wide range of parasitic nematodes may lead to a better understanding of concerted evolution in these organisms.

Animals↗
PubMedDate not supplied

[Mode of penetration and localization of the larvas of Morerastrongylus andersoni (Petter, 1972) (Metastrongyloidea, Nematoda) in the intermediate host].

The way of entry and the localization of the larvae of Morerastrongylus andersoni (Petter, 1972), parasite of African Gerbillidae Rodents, were studied in Limnaea stagnalis L. and Planorbarius corneus (L.). The entry occurs by ingestion: indeed, in the Molluscs killed immediatly after one-half to one hour contact with infested Rodents; droppings, the majority of the larvae are found in the digestive tract. After several hours, the larvae are located in the connective tissue and in the muscles and they are distributed everywhere in the Mollusc's body.

Animals↗