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trichobilharzia ocellata: cercariae masked by antigens of the snail, lymnaea stagnalis. 1977838030
a comparative study of hemocytes from six different snails: morphology and functional aspects.hemocytes taken from six different gastropod snails, achatina achatina, a. fulica, biomphalaria glabrata, bulinus natalensis, helix aspersa, and lymnaea stagnalis, were compared for morphology, peroxidase activity, and, using methods developed for l. stagnalis, the ability to generate reactive oxygen inermediates upon phagocytic stimulation. numbers of hemocytes per milliliter hemolymph and hemocytes' microscopical morphology showed some variation among the snail species. peroxidase activity was ...19921311738
epizootiology of fascioliasis in montana.during 1989-1990, the united states department of agriculture (usda) meat inspection records were used to determine the distribution and incidence of liver flukes (fasciola hepatica and fascioloides magna) in montana cattle. of the cows and bulls slaughtered in usda-inspected packing plants during a 12 month time period, 17.24% had livers that were condemned because of liver flukes. this was a 12% increase over usda liver condemnations reported for 1973. infected animals have been reported from ...19921496783
distribution of catecholamines and of immunoreactivity to substances like vertebrate enzymes for the synthesis of catecholamines within the central nervous system of the snail, lymnaea stagnalis.catecholamines (cas) were detected histochemically within over 185 cell bodies in the central nervous system (cns) of juvenile and young adult lymnaea. this distribution of ca-containing cells in all central ganglia except the pleural ganglia is more widespread than previously described but is consistent with other reports suggesting numerous roles for cas within the nervous system. this study also describes the distribution of substances which are antigenically similar to four bovine enzymes fo ...19901978788
identification of a novel udp-gal:galnac beta 1-4glcnac-r beta 1-3-galactosyltransferase in the connective tissue of the snail lymnaea stagnalis.connective tissue of the freshwater pulmonate lymnaea stagnalis was shown to contain galactosyltransferase activity capable of transferring gal from udp-gal in beta 1-3 linkage to terminal galnac of galnac beta 1-4glcnac-r [r = beta 1-2man alpha 1-o(ch2)8coome, beta 1-ome, or alpha,beta 1-oh]. using galnac beta 1-4glcnac beta 1-2man alpha-1-o(ch2)8coome as substrate, the enzyme showed an absolute requirement for mn2+ with an optimum mn2+ concentration between 12.5 mm and 25 mm. the divalent cati ...19911935942
isolation of schistosomin, a neuropeptide which antagonizes gonadotropic hormones in a freshwater snail.the molecular mechanisms underlying parasite-induced inhibitory effects on host reproduction were studied in the freshwater snail, lymnaea stagnalis, infected with the schistosome parasite trichobilharzia ocellata. this combination is used as a model system for host-parasite interactions involved in schistosomiasis transmission. the female gonadotropic snail neuropeptide, calfluxin, was labelled with fluorescein isothiocyanate (fitc) and used as a ligand in receptor-binding studies on membranes ...19911899379
acth-like molecules in gastropod molluscs: a possible role in ancestral immune response and stress.the presence of immunoreactive acth molecules on phagocytic cells from the freshwater snails planorbarius corneus and lymnaea stagnalis was shown by cytofluorimetric analysis. the role of acth in phagocytosis and in the release of biogenic amines, two biological responses that may be taken as ancestral types of immune response and stress, respectively, has also been evaluated. acth markedly increased the phagocytosis of staphylococcus aureus by p. corneus haemocytes and caused the release of bio ...19911660603
cloning of a cdna that encodes an invertebrate glutamate receptor subunit.a full-length cdna which encodes a putative glutamate receptor polypeptide was isolated from the pond snail lymnaea stagnalis, using a short stretch of exonic sequence and two variants of the polymerase chain reaction. in this first comparison of invertebrate and vertebrate glutamate receptor sequences, the mature molluscan polypeptide, which comprises 898 amino acids and has a predicted mr of 100,913, displays between 37% and 46% amino-acid identity to the rat ionotropic glutamate receptor subu ...19911659993
sequence of a functional invertebrate gabaa receptor subunit which can form a chimeric receptor with a vertebrate alpha subunit.the sequence of an invertebrate gabaa receptor subunit is described. this was deduced from a cdna which was isolated from the mollusc lymnaea stagnalis and which corresponds to a transcript of extremely low abundance. the cdna was isolated using short exonic sequences from part of the corresponding gene in combination with a variant of the polymerase chain reaction (pcr) known as race (rapid amplification of cdna ends). the mature polypeptide has a predicted molecular weight of 54,569 daltons an ...19911655414
the neuropeptide schistosomin and haemolymph from parasitized snails induce similar changes in excitability in neuroendocrine cells controlling reproduction and growth in a freshwater snail.infection of the snail lymnaea stagnalis with the schistosome parasite trichobilharzia ocellata results in inhibition of reproduction and in giant growth. parasite-related effects on the neuroendocrine centres that control these processes were studied electrophysiologically. haemolymph from infected snails reduced the excitability of the caudodorsal cells, which control egg laying. in contrast, the excitability of the growth-controlling light green cells was increased under these conditions. the ...19921641190
biosynthesis and axonal transport of multiple molluscan insulin-related peptides by the neuroendocrine light green cells of lymnaea stagnalis.the neuroendocrine light green cells (lgcs) control body growth and metabolism of the freshwater snail, lymnaea stagnalis. these cells, located in the cerebral ganglia, use the peripheries of the median lip nerves (mlns) as the neurohemal area. the lgcs express four members of a gene family encoding the precursors of distinct though related molluscan insulin-related peptides (mips). the molecular characterization and biosynthesis of mips have been investigated. mln extracts were first size fract ...19921624100
some polypeptides in the nervous system of the marine worm, nereis diversicolor, are related to the sodium influx stimulating peptide of the pulmonate freshwater snail, lymnaea stagnalis.total mrna, extracted from brain of the marine worm, nereis diversicolor (annelida, polychaeta), was translated either in vitro using a rabbit reticulocyte lysate or in ovo (xenopus laevis oocyte). the synthesized polypeptides were analyzed by electrophoresis and western blotting techniques using polyclonal antisera raised against three peptides: sodium influx stimulating peptide (sisp) sequences 10-19 and 67-76 and a monoclonal antibody raised against purified native sisp (1-77) of lymnaea stag ...19921624091
modulation of the activity of the internal defence system of the pond snail lymnaea stagnalis by the avian schistosome trichobilharzia ocellata.effects of infection with the avian schistosome trichobilharzia ocellata on the activity of the internal defence system of the intermediate snail host lymnaea stagnalis were studied, utilizing an in vitro phagocytosis assay for determining haemocyte activity. a distinction was made between plasma- and cell-associated effects. the period immediately after penetration of the parasite into the snail host (1.5-72 h post-exposure (p.e.)) was extensively studied. in addition, several time-points coinc ...19921614738
the laboratory maintenance of sanguinicola inermis plehn, 1905 (digenea: sanguinicolidae).methodology is described for the laboratory maintenance of the life-cycle of sanguinicola inermis, using common carp (cyprinus carpio) as the definitive host and lymnaea peregra as the intermediate host. lymnaea auricularia was also infected but is not considered to be a suitable laboratory host. tench (tinca tinca) were susceptible to infection at high cercarial doses but subsequent infection rates were low. goldfish (carassius auratus) and lymnaea stagnalis were refractory to laboratory infect ...19921614729
in vitro release of the anti-gonadotropic hormone, schistosomin, from the central nervous system of lymnaea stagnalis is induced with a methanolic extract of cercariae of trichobilharzia ocellata.infection with digenetic trematodes causes an inhibition or complete cessation of fecundity in their intermediate hosts, freshwater snails. it has been demonstrated in the host-parasite combination lymnaea stagnalis-trichobilharzia ocellata that the action of the female gonadotropic hormones upon their target organs is inhibited by the peptide schistosomin. schistosomin is produced in the central nervous system of the snail and released upon parasitic infection. in order to study the in vitro re ...19921594294
trichobilharzia ocellata infections in its snail host lymnaea stagnalis: an in vitro study showing direct and indirect effects on the snail internal defence system, via the host central nervous system.in this in vitro study we investigated whether previously described in vivo plasma-associated effects, that occurred in the period shortly after penetration of trichobilharzia ocellata into the snail host lymnaea stagnalis (1.5-72 h post-exposure; p.e.) were direct and/or indirect effects of parasite-derived factor(s). it was investigated whether the effect is mediated by the central nervous system (cns) of the host. phagocytic activity of the haemocytes was taken as a parameter for the activity ...19921461682
the suitability of several aquatic snails as intermediate hosts for angiostrongylus cantonensis.sixteen species of aquatic snails of four families were tested by quantitative technique under standardized conditions for their suitability as intermediate hosts for angiostrongylus cantonensis. these species were the planorbid snails biomphalaria glabrata, biomphalaria alexandrina, planorbis planorbis, planorbis intermixtus, bulinus truncatus, bulinus contortus, bulinus africanus, bulinus tropicus and helisoma sp.; the lymnaeid snails lymnaea natalensis, lymnaea tomentosa, lymnaea stagnalis, a ...19751189583
the emergence of cercariae of trichobilharzia ocellata and its relationship to the activity of its snail host lymnaea stagnalis. 1976985690
sieve structure of slit diaphragms of podocytes and pore cells of gastropod molluscs.the ultrastructure of the slit diaphragms between the pedicels of the podocytes of the prosobranch viviparus viviparus and between the cytoplasmic tongues of the haemocyanin producing pore cells of the pulmonate lymnaea stagnalis was investigated. in both cell types 2 diaphragms are present in the slits. they form a 3-dimensional sieve structure with holes of respectively 90 x 110 a (podocyte) and 200 x 220 a (pore cell). injection experiments showed that the size of the holes of the pore cell s ...1976954055
isthmiophora melis: experimental reinfection of lymnaea stagnalis by implantation of miracidia after implantation of rediae. 1977885211
the production of toxic oxygen metabolites by hemocytes of different snail species.the phagocytic hemocytes of four snail species were investigated for their ability to generate reactive oxygen metabolites upon stimulation by foreign material. hemocytes of the pond snail lymnaea stagnalis and of the garden snail helix aspersa showed a luminol-dependent chemiluminescence (cl) when they phagocytosed zymosan particles. this cl was inhibited by superoxide dismutase (sod) and sodium azide, indicating the involvement of oxygen intermediates. hemocytes of the planorbid snails planorb ...19883169350
life history and habitat analysis of the eye fluke diplostomum spathaceum (trematoda: diplostomatidae) in utah.diplostomum spathaceum which is widespread throughout utah in desert, mountain valley, and high alpine lakes, causes a disease known as diplostomatosis or eye fluke disease. snails (756) were examined and two species, lymnaea stagnalis and l. palustris were positive for d. spathaceum. examination of 838 fish, which included 19 species, revealed 10 species (salmo trutta, catostomus discobulus, salmo clarki, micropterus salmoides, catostomus platyrhynchus, salmo gairdneri, gila atraria, catostomus ...1977864559
neuropeptide schistosomin inhibits hormonally-induced ovulation in the freshwater snail lymnaea stagnalis.this study examines the interaction between the caudodorsal cell hormone (cdch) and schistosomin, a peptide secreted by the central nervous system of the snail (lymnaea stagnalis) infected with the avian schistosome trichobilharzia ocellata. non-infected snails were injected with synthetic as well as native cdch in the absence or presence of purified schistosomin. the response to 2 pmol of synthetic cdch was blocked for 90% by coinjection with 3.5 pmol of schistosomin. the ovulation-inducing act ...19911783894
the occurrence of schistosomin, an antagonist of female gonadotropic hormones, is a general phenomenon in haemolymph of schistosome-infected freshwater snails.in haemolymph of lymnaea stagnalis, parasitized with the digenetic trematode parasite trichobilharzia ocellata, a neuropeptide (schistosomin) occurs which antagonizes female gonadotropic hormones, e.g. calfluxin (cafl). by means of an ultracytochemical hormone-assay, the cafl assay, it was demonstrated that the occurrence of schistosomin is a general phenomenon in schistosome-infected freshwater snails. haemolymph of the schistosomiasis-transmitting snail species biomphalaria glabrata and b. pfe ...19911780174
[identification of catecholamines in the rat brain and mollusk tissues using semithin slices and retrograde staining].the suggested technique allows revealing the transport-specific dye (primulin) and catecholamine fluorescence simultaneously in the same cell of brain. intense fluorescence is observed when brain tissue is quickly dehydrated and embedded in the epoxy resin. the same method is suggested for the identification of catecholamines in the embryonal and juvenile tissues of gastropod lymnaea stagnalis (mollusca pulmonata) without using of primulin dye.19892482195
isolation of mother and daughter sporocysts of trichobilharzia ocellata from lymnaea stagnalis. 19921589436
trichobilharzia ocellata in lymnaea stagnalis: a flow cytometric approach to study its effects on hemocytes.flow cytometric analysis was performed on hemocytes in suspension derived from individual lymnaea stagnalis. the distribution of cell sizes within the hemocyte population was comparable in all 40 specimens studied. the size distribution of circulating hemocytes is unimodal and continuous, with no discrete subpopulations, and is not affected by age or by infection with trichobilharzia ocellata. flow cytometry proved to be a very useful technique in analysis of hemocyte populations in snails and a ...19921541851
alterations in the internal defence system of the pond snail lymnaea stagnalis induced by infection with the schistosome trichobilharzia ocellata.in order to investigate whether the schistosome trichobilharzia ocellata interferes with defence activities in its snail intermediate host lymnaea stagnalis, aspects of the immune system of infected snails and of non-infected controls were compared. the elimination of injected live staphylococcus saprophyticus bacteria starts at a lower rate in infected snails 1 and 5 weeks after exposure to the parasite, but then proceeds faster than in control snails. during the first 3 weeks of infection, whe ...19873809151
[changes in the sulfhydryl group content in the hemolymph of freshwater gastropods infected with trematode parthenitae and larvae].a study was conducted on the changes in sulphhydryl groups in the haemolymph of lymnaea stagnalis infected with partenites of opisthioglyphe ranae, planorbis corneus infected with partenites of cotylurus cornutus and females of viviparus viviparus infected with partenites and larvae of echinoparyphium petrowi. at the infection in the haemolymph of hosts were recorded statystically reliable changes in the protein sulphhydryl groups which are blocked by toxines excreted by the parasites. the reduc ...1978622300
immunocytochemical demonstration of a novel system of neuroendocrine peptidergic neurons in the pond snail lymnaea stagnalis, with antisera to the teleostean hormone hypocalcin and mammalian parathyroid hormone.immunocytochemical staining with antisera raised against trout hypocalcin, the hypocalcemic hormone of the stannius corpuscles and against bovine parathyroid hormone (bpth1-84), revealed a new system of neuroendocrine neurons in the pond snail lymnaea stagnalis. the neurons are located in small groups or single cells in the visceral, parietal, and pedal ganglia of the central nervous system. the axons of these cells are running to the periphery of the pleuroparietal, visceroparietal, and pleurop ...19892767406
carbohydrate and protein in lymnaea stagnalis eggs and trichobilharzia ocellata cercariae. 19744474380
identification of free and conjugated ecdysteroids in cercariae of the schistosome trichobilharzia ocellata.extracts of cercariae of the avian schistosome trichobilharzia ocellata were analysed for the presence of ecdysteroids by radioimmunoassay, high-performance liquid chromatography monitoring fractions by radioimmunoassay, and gas chromatography/mass spectrometry (selected ion monitoring). both free ecdysteroids and polar conjugated ecdysteroids were detected in the cercarial extracts. the free ecdysteroid fraction, as well as the hydrolysed polar conjugated ecdysteroid fraction, contained both ec ...19911775155
neuron-specific monoclonal antibodies raised against the low molecular weight fraction of a brain homogenate of the pond snail lymnaea stagnalis immunoreact with neurons in the central nervous system of the cockroach, the guppy, the wall lizard, the rat and man.monoclonal antibodies were raised against the small molecular weight fraction (less than 30 kilodaltons) of an extract from 200 central nervous systems (cns) of the freshwater snail lymnaea stagnalis. in a first screening step the supernatants of the 297 emerging hybridomas were immunocytochemically tested on sections of the cns of l. stagnalis. sixty-six appeared to produce neuron-specific antibodies, five reacted with non-neuronal elements. in a second step the 66 neuron-specific antibodies we ...19902222891
possible role of reactive forms of oxygen in in vitro killing of schistosoma mansoni sporocysts by hemocytes of lymnaea stagnalis.the interactions between sporocysts of schistosoma mansoni and hemocytes of the pond snail lymnaea stagnalis were studied in an in vitro system. all sporocysts were encapsulated and killed in the hemolymph of juvenile or adult snails within 24 h; the killing patterns of both age groups were not very different. the separation of hemolymph into hemocytes and plasma and subsequent incubation of sporocysts showed that the cells, not the plasma, were responsible for parasite killing. the possible inv ...19882853356
trichobilharzia ocellata: influence of infection on the fecundity of its intermediate snail host lymnaea stagnalis and cercarial induction of the release of schistosomin, a snail neuropeptide antagonizing female gonadotropic hormones.subadult and adult specimens of the pond snail lymnaea stagnalis were infected with the schistosome trichobilharzia ocellata. egg production and growth of the snails were monitored over an 8-week period post-infection (p.i.). snail haemolymph was collected and analysed for the presence of schistosomin, a neuropeptide which antagonizes the action of the snails' female gonadotropic hormones. snails infected as subadults showed an increase in fecundity during the first 4 weeks p.i. compared with no ...19912038502
specificity and memory in increased defence reactions against bacteria in the pond snail lymnaea stagnalis.in lymnaea stagnalis injections with dead escherichia coli or staphylococcus saprophyticus bacteria resulted in an enhanced clearance of both live s. saprophyticus and e. coli injected 4 days later. a non-specific activation of the internal defence system was concluded from these findings. the activation was dose-dependent: pre-injections with high doses resulted in a higher increase in the clearance capacity of the snails than pre-injections with low doses of bacteria. the state of increased ac ...19836357878
primary structure and origin of schistosomin, an anti-gonadotropic neuropeptide of the pond snail lymnaea stagnalis.in the pond snail lymnaea stagnalis infected with the schistosome parasite trichobilharzia ocellata, a peptide called schistosomin is released from the central nervous system, which counteracts the bioactivity of a number of gonadotropic hormones. this leads to inhibition of the reproductive activities of the infected snail. in order to determine the structure of schistosomin, the neuropeptide was purified from the central nervous system using gel-permeation chromatography and reverse-phase h.p. ...19911953679
[experimental reinfection of lymnaea stagnalis with isthmiophora melis (trematoda, echinostomatidae) by exposition to miracidia after implantation of rediae]. 19695372770
trichobilharzia ocellata: interference with endocrine control of female reproduction of lymnaea stagnalis.calfluxin (cafl), one of the gonadotropic hormones of lymnaea stagnalis, stimulates the influx of ca2+ into the mitochondria of the cells of the albumen gland, one of the accessory sex organs of the snail. this effect is suppressed in glands of noninfected snails by an agent (schistosomin) present in the hemolymph of snails infected by trichobilharzia ocellata as shown in in vitro experiments. the agent is present from 6 weeks postinfection onward. ca2+ deposits in the mitochondria were demonstr ...19883338550
effects of trichobilharzia ocellata on hemocytes of lymnaea stagnalis.we analyzed the effects of infection with trichobilharzia ocellata on hemocytes of its snail host, lymnaea stagnalis, and correlated them with successive stages of parasite development. circulating hemocytes were studied at 0, 2, 4, 6, and 8 weeks post exposure (p.e.) with respect to cell number, distribution of subpopulations (as characterized by morphology, determinants recognized by either of two lectins and a monoclonal antibody) and to proliferative, phagocytic and endogenous peroxidase act ...19912060680
[the effect of different concentrations of surface-active substances on the size of the circadian rations and on the duration of food passage in lymnaea stagnalis infected with echinostoma revolutum parthenitae].in solutions of the detergent "kristall" (0.9 and 90 mg.l.-1) there were established statistically reliable differences in the values of day rations and duration of food passing both in infected and free from infection molluscs. in noninfected individuals day rations increase 1.5 to 5 times and the duration of food passing 5 to 7 times. in infected animals the value of day rations decrease and the duration of food passing increases less intensively.19902100003
schistosomin: a pronase-sensitive agent in the hemolymph of trichobilharzia ocellata-infected lymnaea stagnalis inhibits the activity of albumen glands in vitro.the schistosome parasite, trichobilharzia ocellata, nearly completely inhibits the reproductive activity of its intermediate host, lymnaea stagnalis. the synthetic activity of albumen glands of infected snails at day 35 postinfection (p.i.) is only 1% of the control value. the parasite acts by humoral means. we tested the hypothesis that (a) specific humoral agent(s) is (are) involved and refer to this (these) agent(s) as schistosomin. the presence of schistosomin in the hemolymph of infected sn ...19883362828
ultrastructural demonstration of nonsynaptic release sites in the central nervous system of the snail lymnaea stagnalis, the insect periplaneta americana, and the rat.release of neuronal secretory products by exocytosis was studied ultrastructurally in the central nervous systems of three different species (the snail lymnaea stagnalis, the cockroach periplaneta americana and the rat). tissues were fixed with: (1) a mixture of glutaraldehyde and osmium tetroxide, (2) the tannic acid-glutaraldehyde-osmium tetroxide (tago) method, and (3) the tannic acid-ringer incubation (tari) method. especially after tari-treatment, release of the contents of the secretory ve ...19863703256
effects of trichobilharzia ocellata on growth, reproduction, and survival of lymnaea stagnalis. 19695813415
immunocytochemical localization in the central nervous system of four different insect species of molecules immunoreactive against peptides present in the caudodorsal cells of lymnaea stagnalis.the use of polyclonal antisera directed against three peptides (ovulation hormone (cdch), alpha, and beta caudodorsal cell peptide (alpha- and beta-cdcp) produced by the caudodorsal cells of the snail lymnaea stagnalis resulted in positive immunoreaction in sarcophaga bullata (diptera), leptinotarsa decemlineata (coleoptera), locusta migratoria, and periplaneta americana (orthoptera). in three species, colocalization was detected using the antisera against cdch and alpha-cdcp.19902272462
9-amino-1,2,3,4-tetrahydroacridine (tha), an alleged drug for the treatment of alzheimer's disease, inhibits acetylcholinesterase activity and slow outward k+ current.the in vitro release of acetylcholine in rat brain tissue was inhibited by 9-amino-1,2,3,4-tetrahydroacridine (tha). atropine antagonized this effect of tha. as tha does not display an affinity for muscarinic receptors, we conclude that tha inhibits acetylcholinesterase activity. in electrophysiological studies with neurons of lymnaea stagnalis, tha inhibited the slow outward k+ current and consequently increased the duration of the action potentials. it is discussed that both effects of tha pos ...19872444444
effect of infection with trichobilharzia ocellata and schistosoma mansoni on the ultrastructure of the albumen gland of their respective hosts, lymnaea stagnalis and biomphalaria glabrata.the albumen gland, a female accessory sex gland of pulmonate snails, produces the perivitelline fluid. the ultrastructure of the albumen glands of control and infected specimens of lymnaea stagnalis and biomphalaria glabrata was studied. the albumen gland of l. stagnalis contains two types of secretory cells--light (active) and dark (inactive)--and two types of supporting cells--centroacinar and myoepithelial. the secretory cells apparently represent two activity stages of one type of cell. the ...19892606384
in vitro culture of intramolluscan stages of the avian schistosome trichobilharzia ocellata.several different procedures for in vitro cultivation of intramolluscan stages of the avian schistosome trichobilharzia ocellata were tried. a medium was found and culture conditions were established that not only supported in vitro transformation of miracidia into mother sporocysts, but also resulted in substantial subsequent growth; moreover, some degree of germinative development appeared to occur as well. cerebral ganglia from uninfected adult snails of the intermediate host species, lymnaea ...19853892958
galba modicella and lymnaea stagnalis as experimental intermediate hosts for fascioloides magna in minnesota. 19734687484
schistosomin, an antagonist of calfluxin.the percentage of ca2+ positive mitochondria in the cells of the albumen gland of lymnaea stagnalis was used as a measure for the effect of the gonadotropic hormone calfluxin (cafl) and for the interaction between schistosomin, an agent present in the hemolymph of snails infected with the schistosome trichobilharzia ocellata, and cafl. from 3 weeks postexposure on glands of infected snails showed a lower response to cafl than glands of noninfected snails. the response decreased with infection ti ...19882828101
isolation and properties of vitellogenic ferritin from snails.the iron storage protein ferritin is the principal yolk protein in oocytes of the snails planorbarius corneus l. and lymnaea stagnalis l. this report gives an account of the isolation procedure and of some properties of snail ferritins. the isolation procedure includes a heat-denaturation step, gel filtration on sepharose 6b and two ultracentrifugation steps followed by electrophoresis. ferritins from both snails are highly reminiscent of vertebrate and plant ferritins in terms of heat stability ...19826190825
synaptic and nonsynaptic release of neuromediators in the central nervous system.different types of release site were studied ultrastructurally with tannic acid and immunohistochemical techniques in the central nervous system (cns) of the invertebrate pond snail lymnaea stagnalis and in two neuromediator rich core regions in the cns of the rat, viz., the median eminence (me) and the mesencephalic central grey substance (mcg). in the cns of the snail, release of the contents of the secretory granules could be clearly demonstrated in (1) neurohaemal axonterminals, (2) synapses ...19882908165
monoclonal antibody recognized hemocyte subpopulations in juvenile and adult lymnaea stagnalis: functional characteristics and lectin binding.the mouse monoclonal antibody ls1 recognizes a membrane epitope present on circulating hemocytes of the gastropod mollusc lymnaea stagnalis. in both juvenile and adult pond snails, ls1+ (ls1 positive) hemocytes have the morphology of immature cells. the percentage of ls1+ hemocytes is higher in juveniles (ca. 39%) than it is in adults (ca. 14%). functional characteristics of ls1+ hemocytes and lectin binding to these cells were studied. in both age groups, the proliferative activity, as measured ...19883350188
different subpopulations of haemocytes in juvenile, adult and trichobilharzia ocellata infected lymnaea stagnalis: a characterization using monoclonal antibodies. 19854082736
two dopamine receptors: biochemistry, physiology and pharmacology.in 1979, two categories of dopamine (da) receptors (designated as d-1 and d-2) were identified on the basis of the ability of a limited number of agonists and antagonists to discriminate between these two entities. in the past 5 years agonists and antagonists selective for each category of receptor have been identified. using these selective drugs it has been possible to attribute the effects of da upon physiological and biochemical processes to the stimulation of either a d-1 or a d-2 receptor. ...19846390056
elimination of bacteria from the circulation of the pond snail lymnaea stagnalis. 19817009245
the relationship between miracidial dose, production of cercariae, and reproductive activity of the host in the combination trichobilharzia ocellata and lymnaea stagnalis.the effects of exposure of juvenile lymnaea stagnalis to one, two or, four miracidia of trichobilharzia ocellata on the following parameters were studied: infection rate, length of prepatent period, production of cercariae, growth and ovipository activity of the snails, and the weights of their accessory sex organs. an infection rate of 100% was established with all miracidial doses. morality of the snails was low in all experimental groups. in cercarial production high-(hp) and low-productive ( ...19807415420
[seasonal dynamics of infection of snails (lymnaea stagnalis l.) with trematoda in the fish ponds in the stawy milickie reservation area]. 19807424010
trichobilharzia ocellata: physiological characterization of giant growth, glycogen depletion, and absence of reproductive activity in the intermediate snail host, lymnaea stagnalis.giant growth, depletion of energy stores, and inhibition of reproductive activity are striking effects of many trematode parasites on their intermediate snail hosts. two hypotheses have been put forward to explain these phenomena: (1) host and parasite compete for energy rich and other essential nutrients, with the parasite as the winner, and (2) the parasite intervenes in the endocrine control of reproduction of the snail. these hypotheses were tested in the present study with the trichobilharz ...19863720896
contribution to the developmental cycle and taxonomy of neoglyphe sobolevi shaldybin, 1953 (trematoda: omphalometridae).in europe, the life cycle of the trematode n. sobolevi was studied for the first time. following developmental stages are described in detail: daughter sporocysts, cercariae, metacercariae, adults. snails galba corvus and lymnaea stagnalis were found to be the first intermediate hosts in nature. metacercariae were obtained experimentally from larvae of the mosquitoes culex pipiens molestus, adults from the intestine of hamsters (mesocricetus auratus) and mice (mus musculus). this is the first fi ...19892488047
central and peripheral expression of genes coding for egg-laying inducing and insulin-related peptides in a snail.egg laying in the hermaphrodite freshwater snail lymnaea stagnalis is a highly complex activity, including a series of internal activities (ovulation, egg and egg mass formation) which are closely correlated to a pattern of behaviours (alteration of locomotion and feeding, specific postures, oviposition). in this snail egg laying is induced by the neuroendocrine caudodorsal cells (cdcs), consisting of two homogeneous clusters at a total of 100 neurons. at egg laying these neurons release their p ...19892510786
trichobilharzia ocellata: influence of infection on the interaction between the dorsal body hormone, a female gonadotropic hormone, and the follicle cells in the gonad of the intermediate snail host lymnaea stagnalis.activation of adenylate cyclase (ac)-camp system in follicle cells of lymnaea stagnalis by the gonadotropic dorsal body hormone (dbh) is inhibited by schistosomin, an agent present in hemolymph of snails infected with trichobilharzia ocellata. ac activation was determined enzyme cytochemically. this conclusion is based on the observation that the percentage of oocytes with ac-positive follicle cells in gonads incubated in the presence of schistosomin, i.e., in serum of infected snails (is) with ...19892537223
neurons in a variety of molluscs react to antibodies raised against the vd1/rpd2 alpha-neuropeptide of the pond snail lymnaea stagnalis.the vd1 and rpd2 neurons of lymnaea stagnalis innervate other central neurons, certain skin areas, the pneumostome area, and the auricle of the heart. recently, a set of four (delta, epsilon, alpha, beta) neuropeptides produced by these giant neurons and by certain other central neurons has been characterized. although alternative splicing of the preprohormone of these neurons yields at least 10 different alpha neuropeptides, an affinity-purified antiserum directed against a domain common to all ...19938364974
ultrastructural demonstration of exocytosis of neural, neuroendocrine and endocrine secretions with an in vitro tannic acid (tari-) method.the release of neural, neuroendocrine, and endocrine secretory products by exocytosis was ultrastructurally studied by means of tissue incubation in ringer containing tannic acid (tannic acid ringer incubation-method; tari -method), followed by conventional fixation. tannic acid strongly enhances the electron density of extracellular (secretory) substances. during tari -treatment of tissues exocytosis proceeds, but the exteriorized contents of the secretory granules are immediately fixed by tann ...19846373682
identification of a novel udp-galnac:glcnac beta-r beta 1-4 n-acetylgalactosaminyltransferase from the albumen gland and connective tissue of the snail lymnaea stagnalis.both the albumen gland, one of the female accessory sex glands, and connective tissue of the freshwater snail lymnaea stagnalis contain n-acetylgalactosaminyltransferase activity, capable of transferring galnac from udp-galnac in beta 1-4 linkage to the terminal glcnac residue of glcnac beta-r. the albumin gland enzyme was partially purified by affinity chromatography on udp-hexanolamine-sepharose 4b. using glcnac beta 1-2man alpha 1-6(glcnac beta 1-2man alpha 1-3)man beta 1-4glcnac beta 1-4glcn ...19957851383
structure and pharmacological properties of a molluscan glutamate-gated cation channel and its likely role in feeding behavior.we describe the isolation of a molluscan (lymnaea stagnalis) full-length complementary dna that encodes a mature polypeptide (which we have named lym-eglur2) with a predicted molecular weight of 105 kda that exhibits 44-48% identity to the mammalian kainate-selective glutamate receptor glur5, glur6, and glur7 subunits. injection of in vitro-transcribed rna from this clone into xenopus laevis oocytes results in the robust expression of homo-oligomeric cation channels that can be gated by l-glutam ...19968622118
identification and characterization of a udp-galnac:glcnac beta-r beta 1-->4-n-acetylgalactosaminyltransferase from cercariae of the schistosome trichobilharzia ocellata. catalysis of a key step in the synthesis of n,n'-diacetyllactosediamino (lacdinac)-type glycans.three different stages of the avian schistosome trichobilharzia ocellata appeared to contain a novel n-acetylgalactosaminyltransferase activity. to investigate its function in the biosynthesis of schistosome glycoconjugates, the enzyme was partially purified from cercariae, a free-living stage of the parasite, by affinity chromatography on udp-sepharose. acceptor specificity studies showed that the enzyme catalyses the transfer of n-acetylgalactosamine (galnac) from udp-galnac to oligosaccharide ...19947881179
the antagonism between selenium and cadmium in a freshwater mollusc.the protective effect of selenium against cadmium toxicity in rats is well documented. data concerning such protection are lacking in invertebrates. the object of this study was to check whether such an antagonism between se and cd can be found in the freshwater mollusc lymnaea stagnalis l. in the presence of sublethal amounts of selenium, sensitivity with respect to cadmium is nearly halved. sublethal amounts of cadmium give additional protection against the toxic effects of selenium, since thi ...19827073311
development of trichobilharzia ocellata in lymnaea stagnalis and the effects of infection on the reproductive system of the host.juvenile specimens of lymnaea stagnalis were exposed to 0 or 4 miracidia of trichobilharzia ocellata. highly productive infections developed in all infected snails. qualitative and/or quantitative light microscopic observations were performed at various intervals between day 0 and 83 post exposure (p.e.). gonadal maturation started between day 4 and 7 p.e. in all snails, but in infected animals gonadal growth was retarded considerably after day 7 and was blocked from day 19 onwards. this resulte ...19817194549
western blotting of formaldehyde-fixed neuropeptides as small as 400 daltons on gelatin-coated nitrocellulose paper.a method is described for western blotting of peptides as small as 400 daltons (da). peptides were separated by tricine-sodium dodecyl sulfate electrophoresis and electroblotted to gelatin-coated ph79 nitrocellulose paper (0.1 micron). the electroblotted peptides were fixed to the nitrocellulose paper for 5-10 min in 4% paraformaldehyde solution. using anti-rabbit fmrf-amide (phe-met-arg-phe-nh2) as primary antibody, positive immunoreactivity was detected with an amplified alkaline phosphatase a ...19947915887
increased activity of the female gonadotropic hormone producing dorsal bodies in lymnaea stagnalis infected with trichobilharzia ocellata.juvenile specimens of lymnaea stagnalis were exposed to 0 or 4 miracidia of trichobilharzia ocellata. dissection followed at day 22 post exposure. the effects of infection on the activity of the female gonadotropic hormone producing dorsal bodies (db) were studied by phase-contrast and electron microscopy. morphometry shows that the relative volume of db cells of infected snails is 1.6 times as high as in controls. this is mainly due to a 45% higher cytoplasmic volume. the number of profiles of ...19846695535
modulation of the bacterial clearance activity of haemocytes from the freshwater mollusc, lymnaea stagnalis, by the avian schistosome, trichobilharzia ocellata.the ability of haemocytes, from the haemolymph of the gastropod mollusc lymnaea stagnalis, to recognize and eliminate the bacterium aeromonas salmonicida was shown using an in vitro bacterial clearance assay. the assay employs a dye which is reduced by a. salmonicida in direct proportion to the number of viable bacteria resulting in a colour change which can be determined spectrophotometrically. addition of cytochalasin b resulted in a marked decrease in bacterial clearance, implicating both int ...19947970887
cdna cloning and deduced amino acid sequence of two ferritins: soma ferritin and yolk ferritin, from the snail lymnaea stagnalis l.pulmonate freshwater snails contain two different ferritin types, soma ferritin and yolk ferritin. a cdna library was constructed from midgut gland poly(a)-rich rna of the snail lymnaea stagnalis l. and recombinant clones encoding both ferritin types were obtained by immunoscreening. the longest cdna inserts had a length of 859 bp (soma ferritin) and 1548 bp (yolk ferritin) and the specificity of these inserts was confirmed by immunoprecipitation of both ferritin types translated in vitro from h ...19947517354
nitric oxide synthase-immunoreactive cells in the cns and periphery of lymnaea.the presence and distribution of nitric oxide synthase (nos) in the cns and peripheral organs (buccal muscles, oesophagus, salivary glands, foot, mantle and pneumostome) of the pulmonate mollusc, lymnaea stagnalis were studied using an antiserum developed against rat cerebellar nos. nos-immunopositive neurones in lymnaea were localized predominantly in the buccal ganglia as well as in distinct areas of the cerebral and suboesophageal ganglia. nos-immunoreactive terminals were also found on the s ...19947522613
search for shared antigens in the schistosome-snail combination trichobilharzia ocellata-lymnaea stagnalis.mother and daughter sporocysts of tricholbilharzia ocellata, developing in the snail host lymnaea stagnalis, were searched for substances with antigenic similarities to the snail's haemolymph. antisera to cell-free snail haemolymph and fractions thereof were used in three different immunocytochemical staining methods, applied on sections of parasitized snails. snail tissue was consistently stained; cercariae were stained, indicating that the applied methods were successful. most sections through ...19852581390
a lymnaea stagnalis gene, with sequence similarity to that of mammalian beta 1-->4-galactosyltransferases, encodes a novel udp-glcnac:glcnac beta-r beta 1-->4-n-acetylglucosaminyltransferase.a cdna encoding a novel glycosyltransferase, that may be involved in a variant pathway for the synthesis of complex type oligosaccharide chains, was cloned from the pond snail lymnaea stagnalis. by heterologous hybridization, using bovine beta 1-->4-galactosyltransferase cdna as probe, a genomic clone from a snail library was isolated. this genomic clone was subsequently used to clone the corresponding cdna from a prostate gland library. the isolated cdna encodes a polypeptide of 490 amino acids ...19947527028
water snails as paratenic hosts of hymenolepididae fuhrmann, 1907 in czechoslovakia.the distribution of cysticercoids of hymenolepididae fuhrmann, 1907 parasitizing water birds (anseriformes and ralliformes) in czechoslovakia was studied. a total of 2970 snail specimens (429 lymnaea stagnalis (l.), 531 l. ovata (drap.), 1, 462 l. peregra (o. f. müll.), 158 l. auricularia (l.), 262 planorbis planorbis (l.) and 65 viviparus viviparus (l.)) were examined for this purpose. among them, 122 snails were infected with cysticercoids of 13 cestode species (dicranotaenia coronula (dujardi ...19863758867
in the biosynthesis of n-glycans in connective tissue of the snail lymnaea stagnalis of incorporation glcnac by beta 2glcnac-transferase i is an essential prerequisite for the action of beta 2glcnac-transferase ii and beta 2xyl-transferase.using a series of relevant substrates, connective tissue of the snail lymnaea stagnalis was shown to contain beta 1-2 xylosyltransferase (beta 2xyl-t), beta 1-2 n-acetylglucosaminyltransferase i (beta 2glcnac-t i), and beta 1-2 n-acetylglucosaminyltransferase ii (beta 2glcnac-t ii) activities. these enzymes are probably involved in the biosynthesis of the n-linked carbohydrate chains, like those present in hemocyanin. the products formed by incubation of glcnac beta 1-2man alpha 1-6(glcnac beta ...19957556161
characterization of a putative molluscan insulin-related peptide receptor.in the pond snail lymnaea stagnalis (ls), growth and associated processes are likely to be controlled by a family of molluscan insulin-related peptides (mip). here we report on the cloning of a cdna encoding a putative receptor for these mip. this cdna was isolated from ls via pcr with degenerate oligodeoxynucleotides corresponding to conserved parts of the tyrosine kinase domain of the human insulin receptor and its drosophila homologue. many of the typical insulin-receptor features, including ...19957557427
species- and size-specific infection of snails by cyclocoelum mutabile (digenea: cyclocoelidae).infectivity of cyclocoelum mutabile miracidia to 9 species and up to 4 size classes of pulmonate snails at 14, 16, and 20 c was studied under laboratory conditions. of the 9 species examined, 6 (stagnicola elodes, lymnaea stagnalis, gyraulus parvus, gyraulus circumstriatus, promenetus exacuous, and armiger crista) were highly susceptible (infection success > or = 25%), 2 (physa jennessi and helisoma trivolvis) had low susceptibility (infection success < 25%, > 0), and 1 (physa gyrina) was not su ...19957623190
occurrence and distribution of insulin receptor-like immunoreactivity in molluscan brains.insulin receptor-like immunoreactivity (ir) was investigated in the central ganglia of different gastropod molluscs using a monoclonal antiserum raised against an epitope of the human placental insulin receptor. a well detectable and clear location of immunoreactive material was mainly found in the cns of the freshwater snails planorbarius corneus and lymnaea stagnalis. this evidence correlates quite suggestively with the occurrence in these snails of a molluscan insulin peptide (mip) previously ...19937684174
how schistosomes profit from the stress responses they elicit in their hosts.results obtained with the model trichobilharzia ocellata-lymnaea stagnalis have confirmed the hypothesis that the physiological effects evoked by schistosomes in their snail host--castration and giant growth--are brought about by them interfering with the neuroendocrine systems (nes) regulating the physiological processes concerned. as soon as differentiating cercariae are present in the daughter sporocysts a factor can be detected in the haemolymph of the snail host, called schistosomin, which ...19957709853
immunocytochemical identification of neural elements in the central nervous systems of a snail, some insects, a fish, and a mammal with an antiserum to the molluscan cardio-excitatory tetrapeptide fmrf-amide.with an antiserum to the molluscan cardio-excitatory tetrapeptide fmrf-amide neurons and/or nerve fibers were immunocytochemically identified in the central nervous systems of a snail (lymnaea stagnalis), some insects (leptinotarsa decemlineata, periplaneta americana, locusta migratoria, pieris brassicae), a fish (poecilia latipinna) and a mammal (mouse). the fact that immunoreactive material was observed in neurohaemal organs (corpora cardiaca of the insects) as well as in axon terminals ending ...19807006829
schistosomicidal activities of lymnaea stagnalis haemocytes: the role of oxygen radicals.macrophage-like defence cells (haemocytes) of the pond snail lymnaea stagnalis mediate cytotoxicity through reactive oxygen intermediates (rois). this activity is nadph-oxidase dependent, as in mammalian phagocytes during the respiratory burst. in this study, mother sporocysts of schistosomes, the compatible trichobilharzia ocellata and the incompatible schistosoma mansoni evoke in vitro roi activities (detected by luminol dependent chemiluminescence, ldcl) from l. stagnalis haemocytes. s. manso ...19947800416
[investigations on dynamics of somatic growth in juvenile snails lymnaea stagnalis (pulmonata: basommatophora) in conditions of experimental infection with parthenites of the trematode opisthioglyphe ranae (digenia: plagiorchiida)].the effect of exposure of juvenile individuals of lymnaea stagnalis to infectious eggs of opisthioglyphe ranae on dynamics of their growth was investigated under controlled conditions in laboratory. in infected snails enlargement of body weight and linear parameters of shell were observed. any differences in shell shape, analysed on the base of regression of shell width towards to its height, were not ascertained in uninfected snails and those infected with parthenites of the trematode. the find ...19947801640
a novel invertebrate gabaa receptor-like polypeptide. sequence and pattern of gene expression.a full-length complementary dna has been isolated, from the fresh-water mollusc lymnaea stagnalis, that encodes a polypeptide (which we have named zeta) that exhibits between 30% and 40% identity to vertebrate gabaa and glycine receptor subunit sequences. the locations of seven introns have been determined in the corresponding gene and six of these occur at similar relative positions as those found in vertebrate gabaa receptor genes. rnase protection studies have revealed that the transcript for ...19938391989
a new ig-superfamily member, molluscan defence molecule (mdm) from lymnaea stagnalis, is down-regulated during parasitosis.to survive the attacks of the internal defence system (ids) of their host, parasites have developed various strategies to manipulate the ids. we present evidence that the avian schistosome parasite trichobilharzia ocellata affects gene expression in the granular cells, a cell type of the ids of the intermediate host, the mollusc lymnaea stagnalis. from a differential screening, a clone was isolated encoding a protein named molluscan defence molecule (mdm), which encompasses five c2-like immunogl ...19968625992
[investigations on the pathogenesis of changes in somatic growth of lymnaea stagnalis (gastropoda: pulmonata) experimentally infected with parthenites opisthioglyphe ranae (digenea: plagiorchiida). i. relative weight of accessory sex organs and synthetic activity of neurosecretory cells].in the paper an attempt to define pathogenesis of changes in somatic growth of juvenile individuals of the popular freshwater snail lymnaea stagnalis experimentally infected with parthenites of the trematode opisthioglyphe ranae was undertaken. significant enlargement of relative wet weight of examined accessory sex organs (albumen gland, oothecal gland, prostate, male copulatory organ) observed in infected snails permits to explain increase of their somatic growth basing on the hypothesis of di ...19968755148
larval trematode assemblages in the snail lymnaea stagnalis from southeastern wisconsin.from may through november 1993 and 1994, lymnaea stagnalis appressa were collected from a stream adjacent to cedarburg bog, ozaukee county, wisconsin. observations of cercarial shedding and subsequent dissection of snails revealed a relatively depauperate digenean component community consisting primarily of 3 common species. the most frequently occurring form was the metacercaria of cotylurus flabelliformis. sporocysts and cercariae of this species were rarely observed. snails also harbored spor ...19989576497
alpha-lactalbumin affects the acceptor specificity of lymnaea stagnalis albumen gland udp-galnac:glcnac beta-r beta 1-->4-n-acetylgalactosaminyltransferase: synthesis of galnac beta 1-->4glc.the n,n'-diacetyllactosediamine (lacdinac) pathway of complex-type oligosaccharide synthesis is controlled by a udp-galnac:glcnac beta-r beta 1-->4-n-acetylgalac-tesaminyltransferase (beta 4-galnact) that acts analogously to the common udp-gal:glcnac beta-r beta 1-->4-galactosyltransferase (beta 4-galt). lacdinac-based chains particularly occur in invertebrates and cognate beta 4-galnacts have been identified in the snail lymnaea stagnalis, in two schistosomal species, and in several lepldoptera ...19968816760
schistosoma mansoni miracidial host-finding: species specificity of an egyptian strain.the effect of snail-conditioned water (scw) from biomphalaria alexandrina, a pigmented and an albino strain of b. glabrata, and lymnaea stagnalis on the host-finding behavior of miracidia of two brazilian and one egyptian strain of schistosoma mansoni was studied. miracidia of the egyptian strain significantly preferred their suitable host b. alexandrina versus the other snail species with their behavior patterns of host location and their responses after contact with the host. however, miracidi ...19968825437
the use of no-sensitive microelectrodes for direct detection of nitric oxide (no) production in molluscs.the endogenous production of nitric oxide (no) from the cns and a peripheral sensory structure (osphradium) of the pulmonate molluscs, lymnaea stagnalis and limax sp. as well as from the rat aorta was studied using two different types of no-sensitive microelectrodes. both no-sensitive electrodes gave complementary, but comparable results. from our data it was possible to compile a hierarchy of tissues with respect to estimated no production: the rat aorta (300-600 nm) > lymnaea osphradium (100-3 ...19958853686
inhibition of calcium spikes by gamma-amino-butyric acid in the neurons of lymnaea stagnalis l.the modulation of action potentials (aps) and high-threshold calcium currents by gamma-aminobutyric acid (gaba) and gabab receptor agonist baclofen was investigated in identified internally perfused neurons of lymnaea stagnalis using current-clamp and whole-cell voltage-clamp techniques. gaba (5 x 10(-5) m) and baclofen (5 x 10(-5) m) reversibly reduced overshoot and afterhyperpolarization phase of the action potentials. application of gaba or baclofen inhibited inward and outward voltage-gated ...19958853708
biochemical evidence of the sodium influx stimulating related peptide in the brain of the leech theromyzon tessulatum.this paper reports the immunocytochemical and biochemical evidence of a sodium influx stimulating related peptide (sis-like peptide) in the brain of the leech theromyzon tessulatum. cells immunoreactive to both polyclonal antisera raised against the n-terminal (fragment 10-19) or the c-terminal (fragment 67-76) sequences of the purified freshwater snail lymnaea stagnalis sodium influx stimulating peptide (sisp) was detected in the brain of this leech. these immunocytochemical data were strengthe ...19968873139
tyrosine hydroxylase-negative, dopaminergic neurons are targets for transmitter-depleting action of haloperidol in the snail brain.1. the effects of long term administration of micromolar concentrations of the d2 antagonist haloperidol upon monoaminergic neurons in the snail lymnaea stagnalis was investigated. 2. treatment by bath application with 0.5-2.0 micromolar haloperidol, caused a significant, continuous depletion of dopamine levels in the nervous system as revealed by high performance liquid chromatography. 3. a transient depletion of serotonin was also observed, but dopa and norepinephrine levels were unaffected. s ...19968879748
mechanisms underlying digenean-snail specificity: role of miracidial attachment and host plasma factors.digenetic trematodes usually show a high degree of specificity for their molluscan intermediate hosts. a panel of 4 digenean species (echinostoma paraensei, e. trivolvis, schistosoma mansoni, and schistosomatium douthitti) and 5 snail species (biomphalaria glabrata, helisoma trivolvis, lymnaea stagnalis, stagnicola elodes, and helix aspersa representing 3 gastropod families) was used to assess the relative contributions of miracidial behavior, host plasma osmolality, and host plasma factors in d ...200011128473
a comparative study of mechanisms underlying digenean-snail specificity: in vitro interactions between hemocytes and digenean larvae.a panel of 4 digenetic trematode species (echinostoma paraensei, e. trivolvis, schistosoma mansoni, and schistosomatium douthitti) and 5 snail species (biomphalaria glabrata, helisoma trivolvis, lymnaea stagnalis, stagnicola elodes, and helix aspersa) was examined to determine if known patterns of host specificity could be explained by the tendency of digenean larvae to be bound by snail hemocytes, or by the ability of larvae to influence the spreading behavior of hemocytes. in short-term (1 hr) ...200011128474
the production of a stably transformed insect cell line expressing an invertebrate gabaa receptor beta-subunit.we have produced a stable insect cell line derived from spodoptera frugiperda (sf9) cells expressing a cdna encoding a beta-subunit of the lymnaea stagnalis gabaa receptor. the cdna was randomly integrated into the insect cell genome under the control of a baculovirus immediate early gene (ie-1) promoter. stable cell lines were established by transformation of sf9 cells with the expression vector piek1. lgbeta1 together with a plasmid encoding a selectable marker which confers neomycin (g418) re ...19958903929
expression in escherichia coli of a secreted invertebrate ferritin.the coding regions of the cdnas for cytoplasmic soma ferritin and secreted yolk ferritin from the snail lymnaea stagnalis were inserted into the prokaryotic expression vector pemblex2. the vector directed the synthesis in escherichia coli of soma ferritin up to a concentration of 15% of soluble proteins. soma ferritin was expressed as the multimeric protein (480 kda). its similarity with natural soma ferritin was confirmed by page, immunostaining and electron microscopy. yolk ferritin was expres ...19948020474
structural characterization of a lymnaea putative endoprotease related to human furin.a number of peptides have been identified in the central nervous system of the freshwater snail, lymnaea stagnalis, that function as hormones and neurotransmitters/neuromodulators. these peptides are typically proteolytically processed from larger prohormones mostly at sites composed of single or multiple basic amino acid residues. previously we demonstrated a diversity of putative prohormone convertases that may be involved in prohormone processing in the lymnaea brain. in the present report, w ...19948163012
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