| the binding of acidic amino acids to snail, helix aspersa, periesophagic ring membranes reveals a single high-affinity glutamate/kainate site. | the characterization of specific acidic amino acid binding sites to snail, helix aspersa, ganglia membranes has been assayed using tritiated glutamate (l-[3h]glu), aspartate (l-[3h]asp), cysteine sulfinate (l-[3h]csa) and kainate. at 2 degrees c, only l-[3h]glu and [3h]kainate specific binding could be measured using a filtration procedure to separate bound from free ligand. the analysis of l-[3h]glu specific binding reveals the presence of one class of high-affinity binding sites with kd = 0.12 ... | 1986 | 2870764 |
| muscarinic enhancement of the voltage-dependent calcium current in an identified snail neuron. | 1. in the f1 neuron of the snail helix aspersa bathed in a ba2+ and 4-aminopyridine-containing saline, carbamylcholine (cch) enhanced the inward current carried by ba2+ through the voltage-dependent ca2+ channels. 2. this effect of cch on the f1 neuron was not affected by the nicotinic antagonists (+)-tubocurarine and hexamethonium, but it was mimicked by oxotremorine and blocked by both atropine and pirenzepine. 3. the intracellular injection of gtp gamma s (guanosine 5'-o-(3- thiotriphosphate] ... | 1991 | 1850798 |
| binding of the blood group-reactive lectins to human adult kidney specimens. | the binding of a panel of blood group-reactive lectins to frozen sections of human kidney was studied with a special emphasis on reactivity with endothelia and basement membranes. the blood group a-reactive lectins, all specific for alpha-d-n-acetylgalactosamine (galnac), helix aspersa (haa), helix pomatia (hpa), and griffonia simplicifolia i-a4 (gsa-i-a4) agglutinins bound to the endothelium in specimens with blood groups a and ab. in other samples, these lectins reacted predominantly with tubu ... | 1990 | 2297076 |
| [streptococcus agglutinating protectins from helix aspersa, helix lucorum and rapana thomasiana thomasiana crosse]. | | 1970 | 4246057 |
| [variability of reproduction examined in the laboratory between natural populations of helix aspersa müller from the brittany region]. | laboratory experiments were conducted to investigate the effects of geographical localization of natural populations and sampling dates on the reproduction of the garden snail helix aspersa müller. in brittany, reproductive variability between populations shows the adaptive flexibility of characters describing reproductive activity and the relative stability of reproductive ability. | 1991 | 1768314 |
| structure of an invertebrate gene encoding cytoplasmic intermediate filament (if) proteins: implications for the origin and the diversification of if proteins. | the structure of the single gene encoding the cytoplasmic intermediate filament (if) proteins in non-neuronal cells of the gastropod helix aspersa is described. genomic and cdna sequences show that the gene is composed of 10 introns and 11 exons, spanning greater than 60 kb of dna. alternative rna processing accounts for two mrna families which encode two if proteins differing only in their c-terminal sequence. the intron/exon organization of the helix rod domain is identical to that of the vert ... | 1990 | 2249666 |
| gene structure and chromosomal localization of the murine lamin b2 gene. | the structure of the murine lamin b2 gene has been analyzed by cloning, sequencing and hybridization techniques, including in situ hybridization. the gene exists in single copy on the distal arm of chromosome 10 and comprises at least 15 kb, containing 12 exons and 11 introns. the transcriptional start point, as determined by primer extension analysis and rnase protection, was mapped to the region -264 to -254 upstream the atg start codon. the 5' upstream region does not reveal any classical tat ... | 1991 | 1802718 |
| localization of yolk proteins and their possible precursors using polyclonal and monoclonal antibodies, in helix aspersa. | three major yolk proteins of 140, 100, 80 kd and a faint band of 440 kd were determined by gradient gel electrophoresis in the mature eggs of helix aspersa. polyclonal and monoclonal antibodies were raised against mature oocyte extracts. the binding sites of these rabbit and hybridoma antibodies with the different yolk protein components were identified with a combination of western blotting, elisa, immunofluorescence and immunogold staining. all these techniques demonstrated materials immunolog ... | 1991 | 1747899 |
| the primary structure of neuropeptide f (npf) from the garden snail, helix aspersa. | neuropeptide f (npf), originally isolated from the sheep tapeworm, moniezia expansa, consists of 39 amino acid residues terminating in a phenylalaninamide. an analogous neuropeptide has been isolated and sequenced from extracts of circumoesophageal ganglia of the garden snail, helix aspersa. this neuropeptide exhibits partial primary structural similarity to members of the vertebrate neuropeptide y (npy)/pancreatic polypeptide (pp) superfamily. npf is thus of widespread occurrence in the nervous ... | 1992 | 1472263 |
| single and dual infections of the land snail helix aspersa with muellerius capillaris and alloionema appendiculatum (nematoda). | helix aspersa, a land snail, has been experimentally infected with 2 species of nematodes muellerius capillaris and alloionema appendiculatum. a significant reduction of infection with m. capillaris was recorded in snails preinfected with a. appendiculatum, whereas snails preinfected with m. capillaris were as susceptible to a. appendiculatum. | 1990 | 2380869 |
| the neuropeptide fmrfa both inhibits and enhances the ca2+ current in dissociated helix neurons via independent mechanisms. | 1. the modulation of the voltage-activated ca2+ current by the neuropeptide phe-met-arg-phe-nh2 (fmrfa) was investigated in dissociated central neurons from helix aspersa using whole-cell voltage-clamp recording techniques. external ba2+ was always used as the charge carrier in this study, and the intracellular ca2+ concentration was buffered to 20 nm with ethylene glycol-bis(beta-aminoethyl ether)-n,n,n',n'-tetraacetic acid (egta). 2. run-down of the ca2+ currents was not a problem as long as t ... | 1991 | 1652000 |
| low concentrations of neuroactive peptides modulate cholinergic transmission and cyclic amp levels in helix aspersa. | 1. fmrfamide and the catch relaxing peptide (carp) at 0.01-0.1 nm modulate acetylcholine (ach) induced currents of identified neurons of helix aspersa, but have no direct effect on membrane current and conductivity. 2. both fmrfamide and carp noncompetitively inhibit ach cl- responses while having either no effect or increasing ach na+/k+ response. 3. the inhibitory effect of fmrfamide and carp on the ach cl- response was eliminated following pretreatment with forskolin (20 microm), an activator ... | 1992 | 1338559 |
| saccharide residues in human gingiva as revealed with fluorochrome-coupled lectins. | the histochemical binding of 16 fluorochrome-conjugated lectins to human marginal gingiva was investigated. of a total of 14 galactose/n-acetylgalactosamine (gal/galnac)-specific lectins, dolichos biflorus (dba), helix pomatia (hpa), and helix aspersa agglutinins (haa) were blood group a-reactive whereas griffonia simplicifolia i-b4 (gsa-i-b4) and sophora japonica (sja) agglutinins were blood group b-reactive. hpa, haa and gsa-i-b4 bound to all suprabasal epithelial cells and to vascular endothe ... | 1989 | 2542513 |
| relationships between the fmrfamide-related peptides and other peptide families. | the relationships between peptide families are recognized in terms of structural similarity and immunological and biological activity. most of the currently known fmrfamide-related peptides (farps) of molluscs were tested in a radioimmunoassay (ria) and in the two standard bioassays for fmrfamide: the radula protractor muscle of the whelk busycon contrarium, and the isolated heart of the clam mercenaria mercenaria. some peptides were also tested on the heart of the snail helix aspersa. the respo ... | 1988 | 2908809 |
| the moroccan food snail, helix aspersa, as a source of salmonella. | a total of 270 samples, nine lots of 30 samples each, of imported moroccan food snails was examined for the presence of salmonella. eighty-four samples (an overall incidence of 31.11%) and all nine lots contained salmonella. no significant difference (p greater than 0.25) in the number of positive samples was observed by using either selenite cystine both or tetrathionate broth when the samples had been pre-enriched in lactose broth. when used as direct selective enrichments with samples not pre ... | 1975 | 1115505 |
| effects of n-alkanols and a methyl ester on a transient potassium (ia) current in identified neurones from helix aspersa. | 1. a two-microelectrode voltage clamp was used to determine the effects of n-butanol, n-hexanol, n-octanol, n-decanol and methyl hexanoate on a transient potassium (ia) current in identified helix aspersa neurones. experiments were carried out at a temperature of 10-12 degrees c. 2. each n-alkanol reversibly reduced the amplitude of the ia current. logarithmic dose-response curves for the current reduction by each homologue were sigmoidal and had slope factors of around four. the concentrations ... | 1992 | 1293276 |
| [demonstration of the presence and localization of the synthesis of a somatostatin-like substance by immunocytochemistry and hybridization in situ in the brain of helix aspersa]. | the immunocytological method has revealed the presence of somatostatin-like substance (ssi) in the brain of the snail helix aspersa müller. the cerebral green cells (cegc) in the mesocerebron and some neurons in parietal and visceral ganglia react positively with an antibody raised against vertebrate somatostatin-14. the hybridization in situ with an oligonucleotide probe labelled with 35s-datp complementary to the 3'-coding region of rat preprosomatostatin mrna seems to show a colocalization be ... | 1991 | 1678987 |
| the synthesis of vitellogenins by the digestive gland of helix aspersa: evidence from cell-free translation of mrna. | all the rnas were extracted separately from the gonads and digestive glands of the garden snail helix aspersa. after separation by oligo-dt-cellulose chromatography, the mrna were evaluated using optical density measurements and agarose gel electrophoretic analysis and then used in a cell-free translation system: a rabbit reticulocyte lysate added with 35s methionine. the in vitro synthesized proteins were characterized by immunoprecipitation with polyclonal antibodies which were raised against ... | 1992 | 1571947 |
| 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 ... | 1992 | 1311738 |
| thermal susceptibility of salmonella in the moroccan food snail, helix aspersa. | thirty samples of 10-15 helix aspersa food snails were examined for salmonella by a surface rinsing method and by analysis of whole snails rinsed with 70% ethanol. thirteen samples were positive by the rinsing method and 6 were positive by whole snail analysis, with this difference being significant (p less than 0.01). although salmonella contamination in h. aspersa appeared to be predominantly surface, the pathogen was also found within the snail meat. the ability of surface and subsurface salm ... | 1975 | 1194178 |
| occurrence of a blood group a-like substance in eggs of the prosobranch snail pomacea canaliculata. | in the eggs of the prosobranch snails pomacea canaliculata and pomacea insularum a blood group a-like substance has been detected by anti-a from the snails helix pomatia, helix aspersa and cepaea nemoralis. | 1976 | 815102 |
| lactate dehydrogenase in tissue extracts of the land snail, helix aspersa: unique adaptation of ldh subunits in a facultative anaerobe. | | 1977 | 11944 |
| further characterization of some heterophile agglutinins reacting with alkali-labile carbohydrate chains of human erythrocyte glycoproteins. | the nature of the receptor sites for several agglutinins is characterized by hemagglutination inhibition assays. the inhibitory activity of human erythrocytes glycoproteins, from which sialic acid, sialic acid and galactose or alkali-labile oligosaccharides have been removed, is compared to the inhibitory effect of compounds with known structure. it is shown that the lectin from arachis hypogea and anti-t bind to alkali-labile galactosyl-residues. agglutinins from bauhinia purpurea and variegata ... | 1975 | 1172890 |
| dopamine receptors: selective agonists and antagonists of functionally distinct types within the feline brain. | unilateral injections of agents that are useful tools for differentiating electrophysiologically distinct dopamine receptors within the snail helix aspersa are given into behaviourally distinct dopamine sensitive areas within the caudate nucleus of cats. dopamine-elicited contralateral head-turning is selectively mimicked by apomorphine and selectively inhibited by haloperidol, whereas dopamine-elicited homolateral head-turning including oro-facial dyskinesias is selectively mimicked by (3, 4-di ... | 1976 | 986303 |
| 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 ... | 1988 | 3169350 |
| differential expression of galactose and n-acetylgalactosamine residues during fetal development and postnatal maturation of rat glomeruli as revealed with lectin conjugates. | a battery of fluorochrome- or peroxidase-coupled lectins, reacting with alpha- or beta-galactose (gal), terminal n-acetylgalactosamine (galnac), or gal-(beta 1-3)-galnac residues, was used to study the emergence and distribution of cellular glycoconjugates in developing and adult rat glomeruli. neuraminidase pretreatment of the specimens was applied to monitor the maturation of the glomerular sialoglycoprotein coat. in the adult glomeruli, the lectin conjugates applied reacted sparsely or not at ... | 1989 | 2923282 |
| comparative studies of anti-a agglutinins from various snails of the genus helix (helix pomatia and helix aspersa). | | 1973 | 4196846 |
| [relation between muellerius capillaris infestation of molluscan intermediary hosts and of goats in touraine]. | 32 dairy-goat farms of touraine were investigated for muellerius capillaris infection. faecal and molluscs samples were collected in spring and autumn. the factors of risk for goat were the abundance of helix aspersa in spring and of deroceras reticulatum in autumn. the infestivity of pasture was related to the infection of goat in spring but not in autumn. the faecal larval output in goats depended on the breed of goat at both periods; environmental factors were also of importance. | 1986 | 3566083 |
| structure activity studies on dopamine receptors; a comparison between rat striatal adenylate cyclase and helix aspersa neurones [proceedings]. | | 1976 | 974347 |
| [electrophoretic detection of protein fractions in extracts of the ocular tentacles of helix aspersa müller, 1774 (gasteropoda, pulmonata, helicidae)]. | the extracts from ocular tentacles of helix aspersa hare a heterochronic inhibitive action on the development of albumen gland. in view of elucidating the origin of this heterochrony, we make an electrophoretic study of the different extracts from juveniles, adults in activity, in natural sleep and awakning. this study has allowed us to spot 19 proteic fractions common to the four extracts of the tentacles under study, but these fractions show only differences in concentration. particularly, the ... | 1985 | 4091615 |
| studies on the specificity of an acid deoxyribonuclease from helix aspersa (müll.). | | 1973 | 4543958 |
| mechanism of deoxyribonucleic acid degradation by an acid deoxyribonuclease from the snail helix aspersa müll. | | 1972 | 4559795 |
| further investigations on the specificity of an acid deoxyribonuclease from helix aspersa (müll.). | | 1973 | 4589545 |
| lectin binding affinities of induced pancreatic lesions in the hamster model. | we examined the binding pattern of nine lectins to n-nitrosobis(2-oxopropyl)amine (bop)-induced pancreatic lesions in syrian hamsters. these lectins were arachis hypogaea (pna), dolichos biflorus (dba), griffonia simplicifolia i (gs-i), helix aspersa (haa), helix pomatia (hpa), sophora japonica (sja), ricinus communis i (rca-i), triticum vulgaris (wga) and ulex europaeus i (uea-i). all of the lectins reacted in untreated control hamsters to varying intensities with cytoplasmic components of acin ... | 1985 | 4064253 |
| lectin histochemistry of papillary and follicular carcinoma of the thyroid gland. | the lectin-binding properties of human follicular and papillary carcinoma were studied histochemically and compared with lectin binding to normal or goitrous thyroid tissue. well-differentiated minimally invasive follicular carcinoma showed a lectin-binding pattern essentially identical to those of the normal thyroid gland and benign adenomatous lesions. overtly invasive follicular carcinoma showed focal reactivity with some lectins that were nonreactive with normal follicular thyroid cells (sol ... | 1986 | 3089192 |
| purification and properties of an acid deoxyribonuclease from the snail helix aspersa müll. | | 1972 | 5053762 |
| [a synthetic peptide from helix aspersa raises arterial pressure in rats]. | new fmrf-amide like peptide, pglu-asp-pro-phe-leu-arg-phe-nh2, originally isolated from the ganglia of helix aspersa, was synthetized. intravenous injections of this peptide (40-300 micrograms/kg) produce rapid dose dependent increase in the blood pressure and heart rate of anaesthetised rats. since alpha-adrenoreceptor blockade with prazosin eliminated pressor response, it is concluded that the increase in the arterial pressure is mediated by sympathetic activation. | 1988 | 3376629 |
| separation of haemagglutinins from haemolysins in extracts of the albumin gland of helix aspersa. | | 1972 | 4627673 |
| morphine glucuronide hydrolysis: superiority of beta-glucuronidase from patella vulgata. | beta-glucuronidase from patella vulgata, helix aspersa, helix pomatia, and bovine liver were evaluated for usefulness in routine hydrolysis of drug-glucuronic acid conjugates from equine urine samples. factors affecting the reaction rate (enzyme concentration, ligand concentration, temperature, and ph) were optimized. a 3-h incubation at 65 degrees c with 5000 u of beta-glucuronidase from p. vulgata per milliliter of urine resulted in complete hydrolysis of all morphine glucuronide in the urine ... | 1982 | 6799227 |
| induction of macrophage-mediated tumor lysis by an animal lectin, sarcophaga peregrina agglutinin. | several animal lectins, such as sarcophaga peregrina agglutinin, limulus polyhemus agglutinin, helix pomatia agglutinin and helix aspersa agglutinin, were tested for induction of tumor lysis mediated by macrophages. among them, only s. peregrina agglutinin purified from the hemolymph of s. peregrina larvae lysed tumor cells in co-operation with macrophages from the peritoneal cavity of mice. s. peregrina agglutinin alone did not kill target tumor cells. macrophages in the presence of this lectin ... | 1982 | 7152198 |
| darpp-32 like protein in specific snail (helix aspersa) neurones. | monoclonal antibodies to darpp-32 recognise an antigen which is present in specific neurones in the snail (helix aspersa). consecutive sections 10-microns-thick processed for the localisation of darpp-32 and tyrosine-hydroxylase immunoreactivity did not show a coexistence in any neuronal structures. darpp-32 positive cells were, however, often morphologically closely associated with tyrosine-hydroxylase positive cells, implying a functional relationship consistent with the proposed role of darpp ... | 1991 | 1673672 |
| in vitro phagocytosis by amoebocytes from the haemolymph of helix aspersa (müller). i. evidence for opsonic factor(s) in serum. | | 1969 | 5352005 |
| polymorphonuclear leukocyte-mediated cytolysis induced by animal lectin. | nine animal lectins, i.e., sarcophaga peregrina agglutinin, balanus roseus agglutinin, aplysia kurodai agglutinin, balanus balanoides agglutinin, tetraclita squamosa japonica agglutinin, misgurnus anguillicaudatus lectin, asterina pectinifera agglutinin, helix aspersa agglutinin and helix pomatia agglutinin, were tested for induction of cytolysis mediated by polymorphonuclear leukocytes. among them, s. peregrina agglutinin and b. roseus agglutinin lysed murine target cells in co-operation with p ... | 1983 | 6628907 |
| lectin-binding activity and antibody response with pseudomonas paucimobilis and flavobacterium multivorum. | pseudomonas paucimobilis and flavobacterium multivorum (formerly group iik biotype 1 and biotype 2, respectively) showed lectin-binding activity with helix aspersa and no activity with eight other well-characterized lectins. microagglutination titrations and immunodiffusion precipitation revealed specific antibody activity to immunizing antigens. however, no major antigens were found to be common from crude antigen preparations of p. paucimobilis and f. multivorum when tested against opposing an ... | 1983 | 6411314 |
| lectin binding in the anterior segment of the bovine eye. | eleven different fluorescent lectin-conjugates were used to reveal the location of carbohydrate residues in frozen sections of the anterior segment of bovine eyes. the lectins were specific for the following five major carbohydrate groups: (1) glucose/mannose group (concanavalin a (con a)); (2) n-acetylglucosamine group (wheat germ agglutinin (wga)); (3) galactose/n-acetylgalactosamine group (dolichos biflorus agglutinin (dba), helix pomatia agglutinin (hpa), helix aspersa agglutinin (haa), psop ... | 1994 | 7883589 |
| between goat-farm biological variability of the nematode muellerius capillaris first-stage larvea. influence of anthelmintic treatment. | seven dairy-goat farms from the centerwest of france were investigated for morphology and ecology of first-stage larvae (l1) of muellerius capillaris before and after treatment of goats with febantel, a probenzimidazole anthelmintic. the lengths, survivals at 20 and -20 degrees c, and infectivity of l1 to intermediate host helix aspersa, were different between farms. the between farms differences in survivals were reduced after treatment of goats with febantel. the observed between farm differen ... | 1994 | 9140473 |
| eight genes and alternative rna processing pathways generate an unexpectedly large diversity of cytoplasmic intermediate filament proteins in the nematode caenorhabditis elegans. | cytoplasmic intermediate filament (if) proteins of caenorhabditis elegans are encoded by a dispersed multigene family comprising at least eight genes which map to three linkage groups. exon sequences and intron patterns define three distinct subfamilies. while all eight if genes display the long coil 1b subdomain of nuclear lamins, only six genes (a1-a4, b1 and b2) retain a lamin-like tail domain. two genes (c1 and c2) have acquired entirely novel tail domains. the overall sequence identity of t ... | 1994 | 8013462 |
| presence in mouse bone marrow of mediator-dependent cytotoxic effector cells against tumors. | the role of bone marrow cells as cytotoxic effector cells against tumor cells was examined in vitro. bone marrow cells from normal c3h/he mice could lyse murine mm46 tumor cells in the presence of wheat germ agglutinin or syngeneic antitumor antibody. bone marrow cells alone did not cause lysis. eleven other lectins (concanavalin a, phytohemagglutinin, pokeweek mitogen, lens culinaris hemagglutinin, ulex europaeus agglutinin, peanut agglutinin, bandeiraea simplicifolia agglutinin, bauhinia purpu ... | 1983 | 6689597 |
| 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 ... | 1993 | 8364974 |
| the mouse filensin gene: structure and evolutionary relation to other intermediate filament genes. | filensin and phakinin are two lens-specific members of the intermediate filament (if) superfamily of proteins. they coassemble to form a beaded submembraneous filamentous network, the beaded filaments (bfs). the low sequence homology and differences in assembly compared to other if proteins do not allow their classification in any of the five if subgroups. the organization of the phakinin gene exon/intron boundaries provides evidence that this partner may be sharing a common origin with type i c ... | 1997 | 9280315 |
| study on the life cycle of a sexually transmitted nematode parasite of a terrestrial snail. | a technique for the artificial infection of the snail helix aspersa by its parasite the nematode nemhelix bakeri is described. the snail is relaxed by injection of an anesthetic, and 1 gravid female worm is introduced into the genitalia through the genital pore. half of the injected snails were successfully infected. following the course of infection over time indicated a 1:1 sex ratio, that the maximum number of progeny produced by injected female worms was 7, and that the development time of f ... | 1994 | 7799151 |
| [effects of heavy metals on snail development. use of snails as bio-indicators of heavy metal pollution for the preservation of human health]. | the use of snails as biological indicators is particularly appropriate for metals, which they accumulate in their organs. the aim of the present experiment was to carry out a rigorous experimentation in the laboratory and in the wild in order to develop a methodology for the use of snails at a known stage of growth that would give precise information on the toxicity of heavy metals for different concentrations and durations of exposure. we have developed a test of toxicity based on the effects o ... | 1997 | 9162514 |
| molecular and phenotypic features of aeromonads isolated from snails (helix aspersa) affected with a new summer disease. | forty-four aeromonads were isolated during the summer of 1994 from snails (helix aspersa) affected or not by a newly described disease. snta 1 rrna gene restriction patterns (ribotyping) and nine selected conventional phenotypic tests were performed to retrospectively determine relationships among these isolates regarding the disease. results from ribotyping were found highly discriminant in strain differentiation and suggest the possible existence of a group of aeromonas associated with the dis ... | 1997 | 9230675 |
| immunocytochemical distribution of neuropeptide f (npf) in the gastropod mollusc, helix aspersa, and in several other invertebrates. | the distribution of neuropeptide f (npf) immunoreactivity in the snail, helix aspersa, has been demonstrated by immunocytochemistry using 2 region-specific antisera. one, designated npf3, was raised against a synthetic n-terminal fragment of helix aspersa npf; the other, designated pp221, was raised against the c-terminal hexapeptide amide of mammalian pancreatic polypeptide (pp) but cross-reacts fully with the analogous c-terminal region of helix aspersa npf. the distribution of npf immunoreact ... | 1994 | 8111844 |
| cloning of the amiloride-sensitive fmrfamide peptide-gated sodium channel. | the peptide phe-met-arg-phe-nh2 (fmrfamide) and structurally related peptides are present both in invertebrate and vertebrate nervous systems. although they constitute a major class of invertebrate peptide neurotransmitters, the molecular structure of their receptors has not yet been identified. in neurons of the snail helix aspersa, as well as in aplysia bursting and motor neurons, fmrfamide induces a fast excitatory depolarizing response due to direct activation of an amiloride-sensitive na+ c ... | 1995 | 7501021 |
| galactose-deficient iga1 in sera of iga nephropathy patients is present in complexes with igg. | iga1 proteins from sera of patients with iga nephropathy (igan) are galactosylated to a lesser degree than those from healthy controls. the increased reactivity of intact or de-sialylated serum iga1 with n-acetylgalactosamine (galnac)-specific lectins, helix aspersa (haa) and caragana arborescens (caa) and de-sialylated iga1 with helix pomatia (hpa) and bauhinia purpurea (bpa) indicated that the gal deficiency is in glycans located in the hinge region of iga1 molecules. de-sialylated iga from se ... | 1997 | 9264010 |
| the phe-met-arg-phe-amide-activated sodium channel is a tetramer. | the helix aspersa phe-met-arg-phe-amide (fmrfamide)-gated sodium channel is formed by homomultimerization of several fmrfamide-activated na+ channel (fanach) proteins. fanach is homologous to the subunits that compose the amiloride-sensitive epithelial sodium channel, to caenorhabditis elegans degenerins, and to acid-sensing ionic channels. fanach properties were analyzed in stably transfected human embryonic kidney cells (hek-293). the channel was functional with an ec50 for fmrfamide of 1 micr ... | 1998 | 9525939 |
| the first peptide-gated ion channel. | patch-clamp experiments on the c2 neurone of helix aspersa have shown that the neuropeptide phe-met-arg-phe-nh2 (fmrfamide) directly gates a na+ channel. the channel is amiloride-sensitive. activation of this channel is responsible for the fast excitatory action of the peptide. using primers based on amiloride-sensitive epithelial na+ channels, a complete cdna sequence (fanach) was cloned and sequenced from a helix library. the sequence is predicted to have just two membrane-spanning regions and ... | 1997 | 9343851 |
| 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) ... | 2000 | 11128474 |
| highly polymorphic microsatellite markers in the landsnail helix aspersa (mollusca gastropoda). | | 2000 | 10964249 |
| 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 ... | 2000 | 11128473 |
| dgnac1, a gonad-specific amiloride-sensitive na+ channel. | amiloride-sensitive sodium channels have been implicated in reproductive and early developmental processes of several species. these include the fast block of polyspermy in xenopus oocytes that follows the sperm binding to the egg or blastocoel expansion in mammalian embryo. we have now identified a gene called dgnac1 that is specifically expressed in the gonads and early embryo in drosophila melanogaster. the corresponding protein belongs to the superfamily of cationic channels blocked by amilo ... | 1998 | 9545267 |
| double electrophoretic separation and lectin analyses of the component chains of secretory immunoglobulin a from human saliva. | a new method is presented for the separation of secretory immunoglobulin a (siga) from salivary samples. salivary proteins (from parotid or stimulated whole mouth saliva) were precipitated with methanol to concentrate siga from salivary samples whilst removing other salivary proteins. siga purified from breast milk and salivary proteins was separated by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) under nonreducing conditions. following completion of electrophoresis t ... | 2000 | 10832871 |
| intracellular ph regulation in neurons from chemosensitive and nonchemosensitive regions of helix aspersa. | we used 2',7'-bis(carboxyethyl)-5(6)-carboxyflourescein (bcecf), a ph-sensitive fluorescent dye, to study intracellular ph (ph(i)) regulation in neurons in co(2) chemoreceptor and nonchemoreceptor regions in the pulmonate, terrestrial snail, helix aspersa. we studied ph(i) during hypercapnic acidosis, after ammonia prepulse, and during isohydric hypercapnia. in all treatment conditions, ph(i) fell to similar levels in chemoreceptor and nonchemoreceptor regions. however, ph(i) recovery was consis ... | 2000 | 10938227 |
| description of the life-cycle stages of brachylaima cribbi n. sp. (digenea: brachylaimidae) derived from eggs recovered from human faeces in australia. | the life-cycle of brachylaima cribbi n. sp. was established in the laboratory. asymmetrical brachylaimid eggs, measuring 26-32 microm (29.1 microm) long and 16 -17.5 microm (16.6 microm) wide, were recovered from human faeces and fed to the helicid land snail theba pisana as the first intermediate host. sporocysts and cercariae were recovered from the t. pisana eight weeks after infection. the cercariae were used to infect the helicid land snails cernuella virgata and helix aspersa as second int ... | 2001 | 11466482 |
| a time-lapse study of interactions between echinostoma paraensei intramolluscan larval stages and adherent hemocytes from biomphalaria glabrata and helix aspersa. | in vitro interactions between intramolluscan stages (sporocyst, daughter rediae, and metacercariae) of the trematode parasite echinostoma paraensei and adherent hemocytes from the gastropods biomphalaria glabrata (intermediate host) and helix aspersa (non-host) were visualized by time-lapse videomicroscopy. hemocytes of either species not exposed to e. paraensei displayed extensive mobility and activity of cellular extensions. image analysis disclosed no significant change in the total surface a ... | 1994 | 7931907 |
| the susceptibility of inbred mice to infection with brachylaima cribbi (digenea: brachylaimidae). | susceptibility to infection with brachylaima cribbi was studied in eight strains of inbred mice (akr, c3h/hej, cba/cah, balb/c, dba/2j, sjl/j, a/j, c57bl/6j) and swiss albino outbred mice by quantifying faecal egg excretion over the period of the infection. preliminary experiments indicated that a combination of filtration/sedimentation/diethyl ether sedimentation was the most sensitive and reliable technique for quantification of eggs in faeces. mice were infected with 13-15 wild-type b. cribbi ... | 2002 | 11880234 |
| the effects of xenografts of dopamine-rich ganglia from the immature cns of the mollusk helix aspersa l. on learning time during acquisition of an operant food-procuring reflex in wag/rij rats. | | 2002 | 12135336 |
| membrane glycoconjugates expressed on sheep airway epithelium. | in mammalian lung, selective airway inflammatory reactions have been associated with viral infections, transplant rejection, and autoimmune diseases. although the molecular basis for this selective reactivity is unknown, the importance of carbohydrates in immunologic processes suggests a potential role for membrane glycoconjugates in tissue-specific inflammatory reactions. in the present work we examined a panel of 39 lectins for their pattern of reactivity in the peripheral airways of the sheep ... | 1994 | 7930516 |
| mannan-degrading enzymes purified from the crop of the brown garden snail helix aspersa müller (gastropoda pulmonata). | two mannan-degrading enzymes were purified from the crop of the terrestrial snail helix aspersa müller. the crude extracts were taken from dormant (for 4 months) snails. the enzymes were a betad-mannanase of 37.4 +/- 0.3 kda (ec 3.2.1.78) and a betad-mannosidase of 77.8 +/- 1.9 kda (ec 3.2.1.25). both enzymes degraded insoluble mannan, releasing either mannose only (beta-mannosidase) or oligosaccharides, possibly mannotriose and mannopentaose (beta-mannanase). the beta-mannanase had a typical en ... | 2001 | 11471142 |
| cloning and expression of a novel human brain na+ channel. | we have cloned a novel cdna from human brain which encodes a non-voltage-dependent na+ channel (bnc1). bnc1 has some sequence similarity (24-28%) with a new channel family that includes subunits of the mammalian epithelial na+ channel, the caenorhabditis elegans degenerins, and the helix aspersa fmrf-amide-gated na+ channel. like other family members it is inhibited by amiloride. however, its predicted structure differs from other family members, its discrimination between na+ and li+ is differe ... | 1996 | 8626462 |
| specific insulin binding sites in snail (helix aspersa) ganglia. | 1. insulin binding sites were characterized and quantified in snail (helix aspersa) ganglia by incubation of tissue sections with 125i-porcine insulin, autoradiography with [3h]ultrofilm, image analysis coupled to computer-assisted microdensitometry, and comparison with 125i-standards. cellular localization was performed in the same sections by emulsion autoradiography. 2. specific insulin binding sites were demonstrated in discretely localized groups of neurons of the cerebral, pleural, parieta ... | 2009 | 2663169 |
| population genetic structure in a human-disturbed environment: a case study in the land snail helix aspersa (gastropoda: pulmonata). | local patterns of genetic variation were analysed in the land snail helix aspersa for 32 populations sampled within a patchy agricultural landscape: the polders of the bay of mont-saint-michel (france). this investigation examined the allele frequencies at four enzymatic markers and five microsatellite loci through the genotyping of 580 individuals. a strongly significant population genetic substructuring (mean f(st)=0.088, p<0.001) was found at the scale of the whole polders area (3050 ha) and ... | 2003 | 12764420 |
| the effect of mebudipine and dibudipine, two new ca2+ channel blockers, in comparison with nifedipine on ca2+ spikes of f1 neuronal soma membrane in helix aspersa. | mebudipine and dibudipine are two new dihydropyridine (dhp) ca2+ channel blockers that have been synthesized by mahmoudian et al. (1997). in previous studies, they showed considerable relaxant effect on vascular and ileal smooth muscles. these two compounds also reduced the contraction force of rat left atrium (20, 22). in the present study, we attempted to compare the inhibitory actions of these new dhps and nifedipine on the high threshold ca2+ spikes of f1 neuronal soma membrane in the subeso ... | 2003 | 14594195 |
| [effect of dopamine enriched ganglion xenografts from the immature cns of helix aspersa l. snail on the learning time during acquisition of an operant food-procuring reflex in wag/rij rats]. | xenografts from the ganglia of a newborn terrestrial snail helix aspersa l. were implanted into the right parietal area of the brain cortex of wag/rij rats with absence epilepsy. rats with implanted xenografts were trained for reaching a food ball from a tube (reaching test). it was shown that the mean duration of each leaning stage and total time necessary for acquisition of the instrumental conditioning (till the learning criterion) were shorter in animals with xenografts than in control group ... | 2001 | 11550651 |
| the helix aspersa (brown garden snail) allergen repertoire. | ingestion of snails can induce strong asthmatic or anaphylactic responses, mainly in house-dust-mite-sensitized patients. the aim of this study was to identify the helix aspersa (hel a), theba pisana (the p) and otala lactea (ota l) allergens and the extent of their cross-reactivity with the dermatophagoides pteronyssinus (der p) mite. | 2004 | 15591808 |
| characterization of yellow-pigmented and motile enterococci isolated from intestines of the garden snail helix aspersa. | enterococci associated with garden snails (helix aspersa) were studied in order to obtain reliable species identification and characterization. | 2002 | 11972701 |
| evidence for a possible role for nitric oxide in the modulation of heart activity in achatina fulica and helix aspersa. | the effects of nitric oxide (no) donors, s-nitroso-n-acetylpenicillamine, s-nitroso-l-glutathione, sodium nitroprusside and sodium nitrite were investigated on the activity of the isolated hearts of achatina fulica and helix aspersa. no donors inhibited heart activity in a concentration-dependent manner. the only exception was sodium nitroprusside, which excited h. aspersa heart. the inhibitory effects of these no donors were reduced by the no scavenger, methylene blue, the guanylyl cyclase inhi ... | 2004 | 15050921 |
| cloning, isolation, and ige-binding properties of helix aspersa (brown garden snail) tropomyosin. | gastropod consumption is quite frequent in the mediterranean countries and cross-reactivities with crustaceans have been described, but the mechanism of this allergenic cross-reactivity has not been studied in detail. this study aimed to produce recombinant helix aspersa (brown garden snail) tropomyosin and investigate its implication for cross-reactivity among invertebrates. | 2002 | 12065908 |
| palatability of thlaspi caerulescens for snails: influence of zinc and glucosinolates. | * the hypothesis that zinc (zn) hyperaccumulation defends thlaspi caerulescens against herbivores is tested with the snail helix aspersa. we investigated the effects of leaf zinc, cadmium, glucosinolate, nitrogen and dry matter concentrations on the feeding preferences of snails. * four t. caerulescens populations from southern france (two from metalliferous and two from normal soils) were grown on low- and high-zn soils to obtain contrasting leaf zn concentrations. plants were also collected in ... | 2005 | 15720687 |
| use of the land snail helix aspersa as sentinel organism for monitoring ecotoxicologic effects of urban pollution: an integrated approach. | atmospheric pollution from vehicular traffic is a matter of growing interest, often leading to temporary restrictions in urban areas. although guidelines indicate limits for several parameters, the real toxicologic impacts remain largely unexplored in field conditions. in this study our aim was to validate an ecotoxicologic approach to evaluate both bioaccumulation and toxicologic effects caused by airborne pollutants. specimens of the land snail helix aspersa were caged in five sites in the urb ... | 2006 | 16393660 |
| multiple paternity and postcopulatory sexual selection in a hermaphrodite: what influences sperm precedence in the garden snail helix aspersa? | sperm competition has been studied in many gonochoric animals but little is known about its occurrence in simultaneous hermaphrodites, especially in land snails. the reproductive behaviour of the land snail helix aspersa involves several features, like multiple mating, long-term sperm storage and dart-shooting behaviour, which may promote sperm competition. cryptic female choice may also occur through a spermatheca subdivided into tubules, which potentially allows compartmentalized sperm storage ... | 2005 | 15723671 |
| integrated assessment of heavy metal (pb, zn, cd) highway pollution: bioaccumulation in soil, graminaceae and land snails. | to assess the contamination induced by traffic at the vicinity of a highway (a31, france), several complementary studies were carried out on two sites, with different profiles and traffic intensity. concentrations of zinc, lead and cadmium were measured by atomic absorption spectrophotometry in deposits, roadside soil and autochthonous plants (graminaceae) gathered at the vicinity of the highway (1-320 m), and in the viscera of snails helix aspersa, transferred as sentinel in the sites. accordin ... | 2004 | 15081778 |
| reactivities of n-acetylgalactosamine-specific lectins with human iga1 proteins. | lectins are proteins with specificity of binding to certain monosaccharides or oligosaccharides. they can detect abnormal glycosylation patterns on immunoglobulins in patients with various chronic inflammatory diseases, including rheumatoid arthritis and iga nephropathy (igan). however, lectins exhibit binding heterogeneity, depending on their source and methods of isolation. to characterize potential differences in recognition of terminal n-acetylgalactosamine (galnac) on iga1, we evaluated the ... | 2007 | 17275907 |
| increased response to cadmium and bacillus thuringiensis maize toxicity in the snail helix aspersa infected by the nematode phasmarhabditis hermaphrodita. | to determine the effect of nematode infection on the response of snails to selected toxins, we infected helix aspersa with 0-, 0.25-, 1-, or 4-fold the recommended field dose of a commercial nematode application for agricultural use. in the first experiment, the snails also were exposed to cadmium via food and soil at concentrations of 0, 30, 60, 120, or 240 mg/kg in a full-factorial design. in the second experiment, snails were infected with nematodes and also fed either bt (expressing bacillus ... | 2007 | 17269462 |
| effects of subchronic digestive exposure to organic or inorganic cadmium on biomarkers in rat tissues. | in an experimental food chain, wistar rats were fed cadmium (cd) in an inorganic (cdcl(2)) or organic (mainly associated with metallothionein from helix aspersa snail viscera) form. after 1 month of exposure to 100 microg inorganic cd g(-1) in food, an induction of metallothionein was observed in all target tissues. in liver, glutathione peroxidase (gsh-px) activity decreased and alanine aminotransferase (alat) activity increased, suggesting that cd causes hepatotoxicity. however, lipid peroxida ... | 2008 | 17532469 |
| isolation of an anti-a-agglutinin from helix aspersa. | | 2014 | 4537497 |
| metal concentrations in helix pomatia, helix aspersa and arion rufus: a comparative study. | in this study we evaluated the differences between concentrations of copper, iron, zinc, manganese, lead and cadmium in three terrestrial gastropods: helix pomatia, helix aspersa and arion rufus, collected in a semi-rural location in northern italy. metal concentrations in the foot and in the digestive gland were measured. in the hepatopancreas, copper and zinc did not differ significantly in the three species; the levels of copper were also similar in the foot. in comparison to helix sps., a. r ... | 2001 | 11706793 |
| microbiological and chemical analysis of land snails commercialised in sicily. | in this study 160 samples of snails belonging to the species helix aspersa maxima and helix aspersa muller were examined for chemical and microbiological analysis. samples came from greece and poland. results showed mean concentration of cadmium (0.35±0.036 mg/kg) and lead (0.05±0.013 mg/kg) much higher than the limit of detection. mercury levels in both species were not detected. microbiological analysis revealed the absence of salmonella spp. and clostridium spp. in both examined species. e. c ... | 2015 | 27800385 |
| [occurrence of the flagellated protozoan, cryptobia helicis leidy, 1846 (kinetoplasta: bodonea: cryptobiidae) in the garden snail, helix aspersa]. | in this survey, the prevalence and cytological features of the flagellated protozoan, cryptobia helicis living in the bursa copulatrix of the garden snail, helix aspersa müller 1774 found in the vicinity of izmir, turkey was investigated. the prevalence of cryptobia helicis in garden snails collected in the spring of 2005 was found to be 68.65%. this study is the first record of the occurrence of cryptobia helicis in the garden snail helix aspersa found in turkey. | 2008 | 18351561 |
| comparison of reactive processes in the rat brain elicited by xenotransplantation of nervous tissues of chicken or pulmonate snail. | it is known that a histocompatibility system is not developed to the same extent in lower invertebrates as in vertebrate animals. we assumed that the xenografts from the newborn invertebrate nervous system would not exert destructive effects on the brain of the vertebrate recipient even without immunosuppressive therapy. in search of brain xenografts (xg) capable to survive in the brain of a recipient without intensive immunosuppression, we transplanted ganglia of terrestrial snails into the rat ... | 2001 | 11595201 |
| photoperiod is the main cue that triggers supercooling ability in the land snail, helix aspersa (gastropoda: helicidae). | helix aspersa hibernates in brittany (western france), where it may experience subzero temperatures. studies on cold hardiness, although scarce in land snails, have shown a seasonal variation in supercooling ability, associated with high temperatures of crystallization (tc). in the present work, two key environmental factors, temperature and photoperiod, were studied to elucidate, how they may affect the enhancement of supercooling ability in the snails from the end of summer to winter. nine gro ... | 2001 | 11748935 |
| heterologous expression of the invertebrate fmrfamide-gated sodium channel as a mechanism to selectively activate mammalian neurons. | considerable effort has been directed toward the development of methods to selectively activate specific subtypes of neurons. focus has been placed on the heterologous expression of proteins that are capable of exciting neurons in which they are expressed. here we describe the heterologous expression of the invertebrate fmrfamide (h-phenylalanine-methionine-arginine-phenylalanine-nh2) -gated sodium channel from helix aspersa (hafanac) in hippocampal slice cultures. hafanac was co-expressed with ... | 2008 | 18598740 |
| pulsed-field gel electrophoresis profiles of aeromonads isolated from healthy and diseased helix aspersa from french snail farms. | the xbai digestion patterns of chromosomal dna of 42 aeromonads isolated from french breeding snails during a new epizootic disease, which rapidly progressed to death during the summer of 1994, were analyzed by pulsed-field gel electrophoresis. biochemical identification to species level was also performed. interestingly, we found that 76% of the aeromonads isolated from diseased snails clustered into a unique pulsotype (p1) whatever their geographic origin, and were assessed to belong to aeromo ... | 2005 | 16391663 |
| blocking of conditioning of tentacle lowering in the snail (helix aspersa). | experiment 1 established the effectiveness of an appetitive conditioning of odours procedure with snails (helix aspersa) that was subsequently used for the study of blocking. in this important phenomenon, the conditioning of a cs1 (where cs is the conditioned stimulus) prior to conditioning of a compound, cs1cs2, blocked the conditioning to the cs2. experiments 2a, 2b, and 2c demonstrated this associative effect using three different experimental controls. experiments 3a and 3b replicated the bl ... | 2009 | 19214835 |
| morphological and molecular characterization of renal ciliates infecting farmed snails in spain. | renal infections by parasitic ciliates were studied in adult snails of helix aspersa aspersa and helix aspersa maxima collected from 2 mixed rearing system-based heliciculture farms located in galicia (nw spain). the occurrence of ciliates was also examined in slugs (deroceras reticulatum) invading the greenhouses where first growing and fattening of snails is carried out. histological examinations revealed a severe destruction of the renal epithelium in heavily infected hosts. three ciliate iso ... | 2009 | 19402940 |
| natural infection of helix aspersa (mollusca: pulmonata) by dicrocoeliidae (digenea) larval stages in izmir, turkey. | in this study, the prevalence of larval stages of dicrocoeliidae in the garden snail helix aspersa müller, 1774 commonly found in the vicinity of izmir, turkey was investigated and some of its histological and morphological features were determined. the molluscs were collected during the spring of 2005. as the result of the investigation, a land snail species, h. aspersa, was found to be an intermediate host in the life cycle of dicrocoeliidae and it had a prevalence of 0.97 % in the study area. ... | 2007 | 17594660 |
| brachylaima aspersae n. sp. (digenea: brachylaimidae) infecting farmed snails in nw spain: morphology, life cycle, pathology, and implications for heliciculture. | the life cycle of brachylaima aspersae n. sp. (trematoda: brachylaimidae) in heliciculture farms is elucidated in light of field and experimental studies. embryonated asymmetrical eggs (33.3 μm × 20.2 μm) are passed in the faeces of the definitive host, the domestic mouse (mus musculus), and are ingested by its unique first intermediate host, the helicid snail helix aspersa aspersa. after hatching, the miracidium develops into a highly branched sporocyst in the connective tissues of the digestiv ... | 2010 | 21075524 |
| investigations of responses to metal pollution in land snail populations (cantareus aspersus and cepaea nemoralis) from a smelter-impacted area. | a cross-transplantation field experiment was performed to investigate about possible adaptation/acclimatization to metal pollution in common garden snail cantareus aspersus (ex-helix aspersa) and brown-lipped grove snail cepaea nemoralis populations. adults were collected from an area surrounding a former smelter (me), highly polluted by trace metals (tms) for decades, and from an unpolluted site (be). subadults of first generation (f1) were exposed in microcosms in a 28-day kinetic study. four ... | 2011 | 21369962 |
| intrapopulation variation in the standard metabolism of a terrestrial mollusc: repeatability of the co2 production in the land snail helix aspersa. | during the past 2 decades, interest in interindividual variation in performance traits has increased considerably among physiological ecologists. a great deal of this interest has focused on repeatability studies of physiological traits. one of the most important physiological traits in animals is whole-animal metabolism because it reflects several aspects of an organism's energy budget. however, in order to respond to natural selection (ultimately), this variable should be consistent over most ... | 2009 | 19183060 |