Artioposthia Triangulata Research Articles

Immunological approaches to the detection of predation upon New Zealand Flatworms (Tricladida: Terricola): Problems caused by shared epitopes with slugs (Mollusca: Pulmonata)

Abstract The geographical distribution and rate of spread of the earthworm predator Artioposthia triangulata (Dendy), a planarian flatworm accidentally introduced to Britain from New Zealand, is thought to be influenced primarily by ecoclimatic factors. However, anomalies in the expected distribution pattern and population dynamics may be caused in part by predation, and therefore the possibility of using antibodies to detect flatworm remains amongst the gut contents of potential predators was investigated. Cross‐reactivity between an anti‐flatworm polyclonal antiserum and slugs was effectively eliminated by absorption against slug proteins. Similar cross‐reactivity between certain anti‐slug monoclonal antibodies, and flatworms, was also found, indicating similar protein sequences or epitopes. The possibility that these reactions were caused by an immunoglobulin‐binding protein within the flatworms, or endogenous peroxidases affecting ELISA results, was eliminated. Possible evolutionary explanations for such cross‐reactivity are discussed. These results strongly support the need to use fully characterized flatworm‐specific monoclonal antibodies for predation studies in the field, to quantify the role of predation in flatworm population dynamics and to identify potentially useful biological control agents.

The potential spread of terrestrial planarians Artioposthia triangulata and Australoplana sanguinea var. alba to continental Europe

SummaryA survey in Great Britain of the introduced terrestrial planarians Artioposthia triangulata and Australoplana sanguinea var. alba, which are obligate predators of earthworms, indicates that after 30 years Artioposthia triangulata is established throughout Scotland. However, apart from an initial record in 1965, Artioposthia triangulata was unrecorded from England until it was found again in 1992; currently there are 25 records.There are fewer records of Australoplana sanguinea var. alba and these are mainly from the south and west of England. Ecoclimatic data from Edinburgh, where Artioposthia triangulata is common, and Plymouth, close to where Australopiana sanguinea var. alba has been recorded, were used by the computer programme CLIMEX to predict the potential spread of these planarians within Europe. Results suggest that Artioposthia triangulata could become established in north west Europe, including areas of Scandinavia, Germany and Poland, whereas Australoplana sanguinea var. alba would be confined to western Europe, including northern Spain. To slow their spread within Britain and prevent their establishment on continental Europe it is suggested that all nurseries and garden centres which sell containerised plants should initiate and maintain stringent hygiene regimes.

Hydrological and environmental impact of earthworm depletion by the New Zealand flatworm ( Artioposthia triangulata)

The predation of earthworms by the New Zealand flatworm is an environmental threat that may have consequences beyond the scope of merely reducing earthworm populations in the UK. The role of earthworms in developing soil structure is substantial and the effect of structural degradation on hydrological processes, following earthworm eradication, may therefore be major, with a resulting increase in flood risk from river systems and decrease in agricultural productivity of economic concern.

Surface movement rates of the New Zealand flatwormArtioposthia triangulata: potential for spread by active migration

SUMMARYMovement rates for the surface activity of the New Zealand flatwormArtioposthia triangulata(Dendy) (Tricladida: Terricola) were estimated under semi‐field conditions in the Faroe Islands. The distance travelled during 10 consecutive 1‐minute periods per individual was measured from mucus trails left behind as the flatworms moved over black plastic sheeting sprayed with fine droplets of water. Adult specimens were found to crawl at rates of up to 28 cm min‐1(almost 17m h‐1), whereas juveniles crawled at rates of between 3 and 4cm min‐1(approximately 2m h‐1). This study provides the first data concerning the potential for species spread by active migration.

GYIRFamide: A Novel FMRFAmide-Related Peptide (FaRP) from the Triclad Turbellarian, Dugesia tigrina

Modern phylogenetic schemes propose a free-living turbellarian-like organism as the ancestor of all Bilateria, including chordates. While neuropeptides are now known to be of ancient origin within the nervous systems of invertebrates, the neuropeptides of turbellarians remain virtually unexplored. Here we report the primary structure of an FMRFamide-related pentapeptide, Gly-Tyr-Ile-Arg-Phe. amide (GYIRFamide),isolated from an acidified ethanolic extract of the aquatic triclad turbellarian, Dugesia tigrima. Previously, we reported the primary structure, RYIRFamide, from the New Zealand terrestrial turbellarian, Artioposthia triangulata, widely regarded as a most atypical species. However, the present data implies a high degree of primary structural conservation between the FMRFamide-related peptides of both species despite the zoogeographical isolation of the New Zealand form for several hundred million years. In addition, while authentic FMRFamide itself has been identified in many molluscs and a few annelids, the current data would suggest that turbellarian analogues are typically pentapeptides with an X-Y-I-R-Famide motif. A protein/peptide database search revealed that the sequence GYIRF is contained within the primary structure of several bacterial Ni/Fe hydrogenase B-type cytochrome subunits and several proliferating cell nuclear antigens (cyclins) from plants.

Colonisation by the land planarian Artioposthia triangulata and impact on lumbricid earthworms at a horticultural site

Colonisation by the land planarian Artioposthia triangulata and impact on lumbricid earthworms at a horticultural site

Assessment of the global potential distribution of the predatory land planarianArtioposthia triangulata(Dendy) (Tricladida: Terricola) from ecoclimatic data

Abstract Artioposthia triangulata was originally described from New Zealand in 1895 but was subsequently found to have spread to Northern Ireland in 1963 and Scotland and England in 1965. It is now widespread in both Ireland and Scotland, where it has been shown to reduce earthworm numbers to below detectable levels. Ecoclimatic data were used in the computer program CLIMEX to estimate the potential spread of A. triangulata to Europe and the rest of the world. Results indicated it could establish in agricultural land in most of north‐western Europe, and persist in domestic gardens throughout much of central Europe, east and west North America, Australia, southern South America, and South Africa. It is difficult to assess either the extent to which earthworm numbers and diversity would be decreased or how far the effect of their loss to soil structure, nutrient cycling, or wildlife would be detrimental in these areas.

Platyhelminth FMRFamide-related peptides (FaRPs) contract Schistosoma mansoni (Trematoda: Digenea) muscle fibres in vitro.

Molluscan FMRFamide and two recently discovered platyhelminth FMRFamide-related peptides (FaRPs), GNFFRFamide from the cestode Moniezia expansa and RYIRFamide from the terrestrial turbellarian Artioposthia triangulata, cause dose-dependent contractions of individual muscle fibres from Schistosoma mansoni in vitro. The most potent FaRP tested was the turbellarian peptide RYIRFamide, which produced a concentration-dependent effect between 10(-9) and 10(-7) M. FMRFamide and GNFFRFamide were less potent, inducing contractions between 10(-8)-10(-6) M and 10(-7)-10(-5) M respectively. The contractile effect of each of these peptides was blocked by the presence of 1 microM FMR-D-Famide. FMRF free acid did not elicit contraction of the muscle fibres. The FaRP-induced contractions did not occur if the Ca2+ was omitted and 0.5 microM EGTA was added to the extracellular medium. The FaRP-induced contractions were not blocked by the Ca2+ channel blockers nicardipine, verapamil or diltiazem, although high K+-induced contractions of these fibres were blocked by nicardipine. These data indicate the presence of FaRP receptors on schistosome muscle fibres and demonstrate their ability to mediate muscle contraction. The action of these endogenous flatworm peptides on schistosome muscle is the first demonstration of a direct excitatory effect of any putative neurotransmitter on the muscle of a flatworm, and establishes a role for FaRPs in neuromuscular transmission in trematodes. In addition, it provides the first evidence that the peptidergic nervous system is a rational target for chemotherapeutic attack in parasitic platyhelmiths.

Peptides related to the Diploptera punctata allatostatins in nonarthropod invertebrates: an immunocytochemical survey.

The allatostatins are a family of peptides isolated originally from the cockroach, Diploptera punctata. Related peptides have been identified in Periplaneta americana and the blowfly, Calliphora vomitoria. These peptides have been shown to be potent inhibitors of juvenile hormone synthesis in these species. A peptide inhibitor of juvenile hormone biosynthesis has also been isolated from the moth, Manduca sexta; however, this peptide has no structural homology with the D. punctata-type allatostatins. Investigations of the phylogeny of the D. punctata allatostatin peptide family have been started by examining a number of nonarthropod invertebrates for the presence of allatostatin-like molecules using immunocytochemistry with antisera directed against the conserved C-terminal region of this family. Allatostatin-like immunoreactivity (ALIR) was demonstrated in the nervous systems of Hydra oligactis (Hydrozoa), Moniezia expansa (Cestoda), Schistosoma mansoni (Trematoda), Artioposthia triangulata (Turbellaria), Ascaris suum (Nematoda), Lumbricus terrestris (Oligochaeta), Limax pseudoflavus (Gastropoda), and Eledone cirrhosa (Cephalopoda). ALIR could not be demonstrated in Ciona intestinalis (Ascidiacea). These results suggest that molecules related to the allatostatins may play an important role in nervous system function in many invertebrates as well as in insects and that they also have an ancient evolutionary lineage.

A further record of the New Zealand flatworm Artioposthia triangulata (Dendy) in England

Studies have shown the New Zealand flatworm to be a predator of earthworms and to be widely distributed throughout most of Ireland and Scotland. Except for one record in 1965, it had not been found in England until, in December 1992, it was positively identified from a garden centre near Manchester. Viable and empty egg capsules were also found suggesting that it had reproduced and become established in that nursery. During 1993 other confirmed reports were received from Yorkshire and East Anglia, indicating that it may be able to survive and multiply across large areas of England.

RYIRFamide: a turbellarian FMRFamide-related peptide (FaRP)

FMRFamide was isolated originally from neural-tissue extracts of a bivalve mollusc, since when either authentic FMRFamide or a series of structurally-related peptides have been isolated from representative arthropods, annelids and many additional molluscs. However, to date no information exists as to the definitive presence and primary structure of a FaRP in a free-living flatworm. Here, we report the isolation and primary structure of a FaRP from the free-living turbellarian, Artioposthia triangulata, a species from which NPF has been previously structurally-characterised. Unlike molluscs and insects, in which several FaRPs are expressed, only a single member of this family was detected in this turbellarian. The primary structure of this turbellarian FaRP was established as Arg-Tyr-Ile-Arg-Phe-NH 2 (RYIRFamide) and the molecular mass as 752.7 Da. These data have established unequivocally that FaRPs occur in the nervous systems of the most phylogenetically-ancient invertebrates which display bilaterally-symmetrical neuronal plans and that authentic FMRFamide is probably not the original member of the family in molecular evolutionary terms.

Distribution and prevalence of the predatory planarian Artioposthia triangulata (Dendy) (Trieladida: Terricola) in Scotland

SummaryThe distribution of the New Zealand flatworm (Artioposthia triangulata) in Scotland was surveyed between July 1991 and February 1993. There were 348 records from domestic gardens, 56 from botanic gardens, garden centres and nurseries, with only 13 from farms. Although most of the records came from around the major cities the flatworm was found to have become established throughout the Scottish mainland and some of the Islands, e.g. Bute, Gigha, Orkney and Skye.The impact of the flatworm on earthworm populations in agricultural land in Scotland was, as yet, found to be minimal but the fact that seven adjacent farms near Dunoon were infected suggested it could be spread from farm to farm and that in the West of Scotland it could become widespread in agricultural land.

Genetic variation in populations of the terrestrial planarian Artioposthia triangulata (Dendy), and evidence for passive dispersal in Northern Ireland

SummaryGenetic variation in 12 populations of the terrestrial planarian Artioposthia triangulata from Northern Ireland and one in the Republic of Ireland were assessed using starch‐gel electrophoresis. Seven enzymes ‐ adenylate kinase, aspartate aminotransferase, enolase, malate dehydrogenase, phosphoglucose isomerase, phosphomannose isomerase and superoxide dismutase ‐ provided consistent, resolved stains. Coefficients of genetic identity were similar for all comparisons suggesting that the populations did not belong to distinct taxa. There was no relationship between genetic distance and geographic distance for populations, thus confirming the role of passive dispersal in the spread of A. triangulata. Average percentage polymorphic loci and mean heterozygosities were higher in the east of the Province (41.4% and 0.240), than the west (37.5% and 0.185) suggesting that the planarian had spread westwards after an initial colonisation in the east.

Distribution and immunochemical characteristics of neuropeptide F (NPF) ( Moniezia expansa)—immunoreactivity in Proteocephalus pollanicola (Cestoda: proteocephalidea)

1. Using immunocytochemical techniques and confocal scanning laser microscopy, the proteocephalidean cestode, Proteocephalus pollanicola from Lough Neagh pollan ( Coregonus autumnalis) was examined for the presence of the native platyhelminth neuropeptide, neuropeptide F (NPF). 2. An antiserum specific for whole-molecule NPF(1–39) ( Moniezia expansa) did not immunostain nerve processes in P. pollanicola. A C-terminally-directed NPF(30–39) ( M. expansa) antiserum immunostained nerve fibres and cell bodies of both the central and peripheral nervous systems, including innervation associated with the female reproductive system. 3. The pattern of immunoreactivity was identical to that obtained using antisera to the C-terminal region of mammalian NPY-superfamily peptides and the invertebrate neuropeptide, FMRFamide. 4. Under radioimmunoassay conditions, only the C-terminally-directed NPF antiserum cross-reacted with the P. pollanicola peptide and detected 58.74 ng g wet weight of NPF-IR in extracts of the worm. 5. Chromatographic characterisation of P. pollanicola NPF-immunoreactivity indicated an apparent molecular weight of 4400–4700 Da, similar to that of NPF ( M. expansa). 6. Further analytical HPLC characterisation identified two molecular forms of P. pollanicola NPF-immunoreactivity, both of which had different retention times from those of NPF ( M. expansa) and NPF ( Artioposthia triangulata). 7. These data suggest that P. pollanicola possesses a neuropeptide which is homologous in its C-terminal region to NPF ( M. expansa) but diners in its mid- to N-terminal region.

The effect of starvation on size and survival of the terrestrial planarian Artioposthia triangulata (Dendy) (Tricladida: Terricola)

SummaryTen Artioposthia triangulata were kept without food at 5°C, 10°C, 15°C, 20°C and 23°C. Survival and weights were recorded weekly. All planarians died within one week at 23°C and within three weeks at 20°C. One individual survived for 60 wk at 5°C. A negative exponential equation was fitted to average survival times for planarians kept at 5°C, 10°C, 15°C and 20°C. Negative exponential models could also describe the pattern of degrowth by planarians deprived of food. The results are discussed in relation to possible survival of the planarian outdoors in Northern Ireland and the implications for earthworm populations.

Neuropeptide F: Primary structure from the tubellarian, Artioposthia triangulata

1. A neuropeptide exhibiting vertebrate pancreatic polypeptide immunoreactivity has been isolated and sequenced from extracts of the terrestrial turbellarian, Artioposthia triangulata. 2. This neuropeptide, designated neuropeptide F, consists of 36 amino acid residues terminating in a phenylalaninamide. 3. The full primary structure was established as: KVVHLRPRSSFSSEDEYQIYLRNVSKYIQLYGR-PRF.NH 2. The molecular mass, deduced from this sequence, was 4433 Da. 4. This neuropeptide exhibits C-terminal homology with neuropeptide F ( Moniezia expansa) and with the vertebrate neuropeptide Y/pancreatic polypeptide superfamily of which it may represent a phylogenetic precursor.