Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| molecular characterization of a centromeric satellite dna in the hemiclonal hybrid frog rana esculenta and its parental species. | hybrid water frogs rana esculenta reproduce by hybridogenesis: one parental genome (of rana lessonae) is excluded in the germ line, the other (of rana ridibunda) is clonally transmitted to haploid gametes. the two parental species differ in that the amount of centromeric heterochromatin revealed by differential staining is much higher in rana ridibunda. an abundant, tandemly arrayed, centromeric satellite dna, designated rrs1, is revealed in rana ridibunda genomes by the restriction endonuclease ... | 1995 | 8581303 |
| effect of thyroid state on cardiac electrical activity of the frog rana esculenta. | the effects of altered thyroid states on the heart rate and ventricular electrophysiological properties of the frog were examined. hypothyroidism was induced by a 10-day treatment with propylthiouracil and produced decreased serum-free and total triiodothyronine levels below detectable concentrations. hyperthyroidism, elicited by a 5-day treatment with triiodothyronine, was associated with increased serum thyroid hormone levels. the hypothyroid state was associated with a significantly decreased ... | 1995 | 8582597 |
| localization of gnrh molecular forms in the brain, pituitary, and testis of the frog, rana esculenta. | in the amphibian brain four molecular forms of gnrh have been identified so far: mammalian gnrh (m- and hydroxyproline9m-), chicken ii gnrh (cii), and a salmon (s) gnrh-like peptide. in rana esculenta, cii- and s-gnrh-like molecules have been partially characterized in the brain extracts using hplc combined with radioimmunoassay. moreover, since cii-gnrh-like material has been detected in rana esculenta testis, the present study describes the localization of the above peptides in the brain and t ... | 1996 | 8583206 |
| distinct hydro-osmotic receptors for the neurohypophysial peptides vasotocin and hydrins in the frog rana esculenta. | the biological properties of vasotocin, hydrin 1 (vasotocinyl-gly-lys-arg) and hydrin 2 (vasotocinyl-gly), in particular the hydro-osmotic activities on the frog skin, the frog urinary bladder and the frog kidney, have been compared. hydrins are as active or more active than vasotocin on the first two organs but they are virtually devoid of antidiuretic activity in the rat and the frog, in contrast to vasotocin. it appears that where the oxytocin ring (residues 1-6), present in the three peptide ... | 1995 | 8587666 |
| development and distribution of gonadotropin-releasing hormone neuronal systems in the frog (rana esculenta) brain: immunohistochemical analysis. | the ontogenesis of the gonadotropin-releasing hormone (gnrh) neuronal systems was studied in the brain of the frog, rana esculenta. attention was also focussed on the differential distribution of molecular forms of gnrh during development. the first gnrh-immunoreactive neurons appear in the mesencephalon of posterior limb-stage tadpoles. these neurons are shown to contain only chicken [his5,trp7,tyr8]gnrh (cgnrh-ii). later in development, mammalian [tyr5,leu7,arg8] gnrh (mgnrh)-like peptide-cont ... | 1995 | 8612331 |
| induction of s-phase entry by a gonadotropin releasing hormone agonist (buserelin) in the frog, rana esculenta, primary spermatogonia. | in the testis of the frog, rana esculenta, mitotic activity of primary spermatogonia is regulated by gonadotropins and synergistically by testosterone. in addition gnrh-like material directly stimulates gonadal activity. intact animals were treated with a gnrh agonist (gnrha, buserelin, hoechst) and/or a gnrh antagonist giving injections intraperitoneally on alternate days for 15 days. moreover, testes were treated in vitro for 24 hr with gnrha. 3h-thymidine and colchicine were used to assess th ... | 1996 | 8665406 |
| multihormonal control of vitellogenin mrna expression in the liver of frog, rana esculenta. | in rana esculenta in an in vitro system, hepatic vitellogenin synthesis can be induced by growth hormone in both sexes. in this study: (1) the ability of this hormone to induce transcription of the vtg gene was determined, and (2) this ability was compared with that of estradiol-17 beta. the results indicate that growth hormone stimulates vtg mrna transcription both in vivo and in vitro, in both sexes. the levels of mrna are related to protein levels in the medium. in addition, seasonal variatio ... | 1995 | 8674844 |
| possible mechanism for the first response to short captivity stress in the water frog, rana esculenta. | to clarify the endocrine mechanism involved in the short captivity stress in the water frog, rana esculenta, the activity of 9-ketoreductase, the enzyme which converts prostaglandin e2 (pge2) into prostaglandin f2 alpha (pgf2 alpha), and aromatase, which converts testosterone into oestradiol-17 beta, were studied. adult male and female frogs were sacrificed 0, 1.5, 3, 6, 12, 24, 48, 72, 168 and 336 h after capture in the field. pge2, pgf2 alpha, progesterone, testosterone, oestradiol-17 beta and ... | 1996 | 8699137 |
| correlation between chloride flux via the mitochondria-rich cells and transepithelial water movement in isolated frog skin (rana esculenta). | the coupling between net transepithelial cl- influx and net water flow was investigated. experiments were performed on isolated frog skin bathed in isotonic cl- ringer's solution in the presence of the na+ channel blocking agent amiloride in the mucosal solution. the skins were voltage-clamped at -80 or -100 mv (with the serosal solution as reference). under these conditions the current across the skin is carried by an influx of cl-. in the absence of antidiuretic hormone the correlation between ... | 1995 | 8719255 |
| ca selectivity of the transduction channels in the hair cells of the frog sacculus. | the extracellular receptor currents evoked by step displacements of the otolithic membrane of the isolated saccular macula of rana esculenta were recorded under transepithelial voltage clamp conditions. with the aim to depolarize the hair cells and increase the fractional resistance of the apical membranes, the basal side of the preparation was bathed in saline with an increased k+ concentration (62 mm). this caused a shift in the non-linear receptor current-voltage relation along the voltage ax ... | 1995 | 8719256 |
| occurrence of androgen and estrogen receptor mrnas in the harderian gland: a comparative survey. | in rana esculenta the presence of an androgen receptor in both the male and female harderian gland (hg) has been demonstrated. hybridization analysis has evidenced a high degree of homology between the rat androgen receptor cdna and the frog androgen receptor mrna (farmrna). correspondingly the molecular size of farmrna is similar to those described in mammals (9.4 kb). in in vivo experiments testosterone (t) increases the levels of farmrna. the use of the antiandrogen alone or in combination wi ... | 1996 | 8722702 |
| [a genetic analysis of the structure of hybrid populations of the green frog rana esculenta l. complex (amphibia, ranidae) in volhynia]. | analysis of the genetic structure of two green frog rana esculenta complex populations from volyn' was performed for 7 diagnostical loci. populations of r- and rel-type were detected in which the introgression of ldh-b allelic gene locus from r. lessonae into genome of r. ridibunda, characteristic for hybrid populations of dnieper basin, was absent. this may be associated with alterations in gene pools of parental species. | 1996 | 8743018 |
| distribution of neuromedin u-like immunoreactivity in the central nervous system of rana esculenta. | the distribution of perikarya and nerve fibers containing neuromedin u-like immunoreactivity in the brain of rana esculenta was determined with an antiserum directed toward the carboxyl terminus of the peptide. in the telencephalon, immunoreactive perikarya were found in the olfactory bulb, the medial septum, and the diagonal band. in the diencephalon, labeled perikarya were detected in the anterior and posterior preoptic areas, the dorsal nucleus of the hypothalamus, the caudal part of the infu ... | 1996 | 8743423 |
| neuropeptide y: localization in the brain and pituitary of the developing frog (rana esculenta). | the immunohistochemical localization of neuropeptide y (npy)-like peptide has been investigated in the peripheral terminal nerve, brain and pituitary of the frog, rana esculenta, during development. soon after hatching, a rather simple npy-immunoreactive (-ir) neuronal system is present, with elements located mainly in the diencephalon. when hind limbs appear and develop, the npy-neuronal system undergoes considerable elaboration and npy-ir perikarya appear in several regions of the telencephalo ... | 1996 | 8766161 |
| immunoreactive mammalian and chicken-ii gnrhs in rana esculenta brain during development. | two forms of gonadotropin-releasing hormone (mammalian, mgnrh and chicken-ii, cgnrh-ii) were measured by radioimmunoassay in the nasal area (containing peripheral terminal nerve), brain and pituitary of rana esculenta during larval development, metamorphosis, and until prior to becoming reproductively active. small amounts of both forms of gnrh were first detected in the brain extract of early tadpoles (stage 26-27, when hindlimbs begin to develop). later, there was a gradual, but constant, stag ... | 1996 | 8795074 |
| effect of calcitonin gene-related peptide on sodium absorption through isolated skin of rana esculenta. | calcitonin gene-related peptide (cgrp) added to the internal fluid bathing the isolated skin of rana esculenta strongly stimulates the active sodium absorption. this action is dose-dependent, the dose eliciting the maximal effect being 2 . 10(-7) m; alpha and beta cgrp exhibit the same potency. the cgrp action on sodium transport is mainly due to its interaction with cgrp1 receptors, since it is inhibited by cgrp8-37, its specific antagonist. the second messengers probably involved in the action ... | 1996 | 8818196 |
| biochemical and cytochemical analyses of bnp-stimulated guanylate cyclase in frog choroid plexus. | this study shows that in the choroid plexus of rana esculenta particulate guanylate cyclase (gc) is appreciably stimulated by porcine brain natriuretic peptide (bnp). ultracytochemical tests for gc show that bnp notably increases the enzymatic reaction product along the apical surfaces of the epithelial cells. it can therefore be hypothesized that the apical zone of the epithelial cells possess receptors which have a particular affinity for bnp produced in the central nervous system and dumped i ... | 1995 | 8821760 |
| organization of the ambiguus nucleus in the frog (rana esculenta). | the common root of the glossopharyngeal, vagal, and accessory nerves and the individual branches of the vagus complex were labeled with cobalt, and the organization of the ambiguus nucleus was studied. the cell column labeled through the common root extended from the upper part of the medulla to the rostral spinal cord over a distance of about 3,500 microns. the labeling of individual branches revealed four subdivisions. 1) the pharyngomotor subdivision occupied the rostral 800 microns of the ce ... | 1996 | 8835731 |
| molecular cloning of a novel mrna (harderin) specifically and highly expressed in the harderian gland of the frog, rana esculenta. | a cdna clone encoding a novel mrna (harderin) has been isolated from the cdna library of frog rana esculenta harderian gland. the cdna is 875 bp long and encodes a novel protein of 218 amino acid residues. the deduced proteins reveals no significant homology to other proteins. the mrna is a single 0.9 kb transcript detected only in the rna of frog harderian gland, highly expressed throughout the year. the constant and exclusive presence of harderin in the frog harderian gland, suggests a constit ... | 1996 | 8850536 |
| distribution of fmrfamide-like immunoreactivity in the brain and pituitary of rana esculenta during development. | developmental aspects of the distribution of fmrfamide (phe-met-arg-phe-nh2) immunoreactivity (ir) were investigated by indirect immunofluorescence in the brain, pituitary and terminal nerve of the frog, rana esculenta. soon after hatching. fmrfamide neurons were found in the proximal terminal nerve, mediobasal olfactory bulb, caudal dorsolateral pallium, diagonal band of broca, anterior preoptic area, suprachiasmatic area, thalamus, infundibulum, and developing pituitary. fmrfamide fibers were ... | 1996 | 8874894 |
| temperature dependence of spontaneous otoacoustic emissions in the edible frog (rana esculenta). | the change in frequency of individual emissions in the european edible frog (rana esculenta) when the temperature of the frog is modified, is part of a complex pattern of interaction between spontaneous otoacoustic emissions. at high temperatures (above 24 degrees c) two emissions are always detected (e.g., one near 800 hz and one near 1200 hz). the higher-frequency emission is lower in level and has a wider bandwidth than the lower-frequency emission. it is also often asymmetric and sometimes b ... | 1996 | 8880178 |
| fat body of the frog rana esculenta: an ultrastructural study. | in the frog, the fat body is the largest body lipid deposit and is associated with the gonad. the aim of the present work was to investigate the fine structure of the fat body at different periods of the annual cycle and during prolonged starvation. results indicate that fat body cells of rana esculenta caught in autumn and after winter hibernation resemble mammalian adipocytes of white adipose tissue and contain markers of adipose tissue, such as s-100 protein and lipoproteinlipase. however, un ... | 1996 | 8907147 |
| insp3-dependent ca2+ oscillations linked to activation of voltage-dependent h+ conductance in rana esculenta oocytes. | in normal medium supplemented with 10 mm tetraethylammonium chloride (teacl), membrane depolarizations of immature rana esculenta oocytes elicited an oscillatory outward current associated with a voltage-dependent h+ current (ih+). the voltage threshold of these oscillations was 22 +/- 5 (n = 10). the oscillations were blocked by intracellular injection of ethylene glycol-o,o'-bis-(2-acetaminoethyl)-n,n,n',n'-tetraacetic acid (egta), by application of 1 mm of 4-acetamido-4'-isocyanatostilbene-2, ... | 1996 | 8911687 |
| immunohistochemical demonstration of fsh and lh in the pituitary of the developing frog, rana esculenta. | the ontogenetic pattern of immunohistochemically detectable fsh beta and lh beta cells was investigated in the pars distalis of the pituitary of the frog, rana esculenta. the appearance, distribution, and percentage of these cells were examined in tadpoles from soon after hatching to the end of metamorphosis and in juveniles. we used monoclonal antibodies against bullfrog fsh beta and lh beta for single staining, and either mouse anti-bullfrog lh beta + guinea pig anti-rat fsh beta or rabbit pol ... | 1996 | 8930609 |
| distribution of somatostatin-immunoreactive structures in the central nervous system of the frog, rana esculenta. | the distribution of somatostatin-containing structures in the central nervous system of the frog, rana esculenta, was studied using the peroxidase immunohistochemical method. immunoreactive elements were widely distributed in several regions of the central nervous system. with the exception of the primordium hippocampi, where a few stained perikarya were revealed, the pallium were free of immunoreactivity. in subcortical regions of the telencephalon, immunoreactive varicose fibers were observed ... | 1996 | 8964969 |
| prostaglandin e2 inhibits antidiuretic hormone induced transepithelial sodium transport and camp production in frog skin epithelium (rana esculenta). | the stimulation of transepithelial sodium transport by arginine vasotocin (avt) and the ability of prostaglandin e2 (pge2) to inhibit the avt dependent sodium transport was examined on pieces of frog skin taken from different regions of the frog. the basal sodium transport was of the same magnitude in the abdominal, thoracal and upper and lower dorsal region. in all regions the sodium transport could be stimulated by avt, though the stimulation was highest in the abdomen. subsequent addition of ... | 1996 | 8971257 |
| characterization of pars intermedia connections in amphibians by biocytin tract tracing and immunofluorescence aided by confocal microscopy. | biocytin, recently introduced in neuroanatomical studies, was used as a retrograde tract tracer in combination with immunofluorescence in order to analyse the neurochemical characters of some central neuronal projections to the pars intermedia in two amphibian species, the anuran rana esculenta and the urodele triturus carnifex. after biocytin insertions in the pars intermedia, neurons became retrogradely labelled in the suprachiasmatic hypothalamus and the locus coeruleus of the brainstem in bo ... | 1997 | 8995200 |
| seasonal variations in the frontal organ of the frog: structural evidence and physiological correlates. | histological study of the frontal organ in the frog, rana esculenta, was performed during spring, summer, autumn and winter. in semithin sections stained with toluidine blue, cells containing a vacuole were clearly detected during spring, and considerably increased during summer. such cellular elements were absent in the frontal organ during autumn and winter. this morphological evidence of seasonal variation was supported by extracellular recording in the frontal organ in different seasons. spo ... | 1997 | 9011034 |
| temporins, antimicrobial peptides from the european red frog rana temporaria. | a cdna library from the skin of rana temporaria has been screened using a cdna fragment probe that encodes the signal peptide of the precursor of esculentin from the skin secretion of rana esculenta. with this approach, the cdnas encoding the precursors of three peptides were isolated. subsequently, the peptides predicted from the sequence of the cloned cdnas as well as several structurally related peptides could be isolated from the skin secretion of r. temporaria. these peptides, which were na ... | 1996 | 9022710 |
| reinnervation of frog sympathetic ganglia after selective denervation of b or c neurons. | selective transection of the b or c preganglionic nerve fibres respectively innervating the b and c sympathetic neurons was carried out on the last two ganglia of the sympathetic chain of the frog rana esculenta. at different times thereafter, the cross-reinnervation of one type of denervated neuron by nerve endings sprouting within the ganglia from intact fibres innervating the other type was investigated by both the quantitative morphology of the synaptic contacts and related structures and el ... | 1996 | 9023723 |
| an ultrastructural and cytochemical study of the mesonephros of rana esculenta during activity and hibernation. | the biological cycle of most amphibians undergoes seasonal variations. in this study, we investigated the mesonephros of rana esculenta during active life and the natural hibernation period. the ultrastructural morphology of the different tracts constituting the nephron was analysed. moreover, to evaluate the effect of seasonal temperature variations on the mesonephros function, the activity of some enzymes linked to membrane transport and playing regulatory roles in various metabolic pathways w ... | 1996 | 9090990 |
| the fine structure of the lateral geniculate complex in the frog rana esculenta. | the lateral geniculate complex of the frog is composed of two neuropil areas, the neuropil of bellonci and the corpus geniculatum thalamicum that receive axons of retinal origin. the nucleus of bellonci, and some other cell groups project dendrites into the neuropil. in normal animals three types of axon terminals (a1, a2, a3), light and dark dendrites, dendritic appendages and presynaptic dendrites were distinguished as components of the lateral geniculate circuitry. using horseradish peroxidas ... | 1996 | 9123998 |
| connections of the torus semicircularis and oliva superior in the frog, rana esculenta: a phaseolus vulgaris leucoagglutinin labeling study. | the afferent and efferent connections of the frog principal nucleus (tp) of torus semicircularis (tos) and superior olive (so) were examined by employing the anterograde and retrograde transport patterns of phaseolus vulgaris leucoagglutinin (pha-l). after injecting the tracer into these nuclei it was found that the tp projected to the ipsilateral posterior and central thalamic nuclei, all subdivisions of the bilateral tds and the ipsilateral nucleus isthmi (ni). in the rhombencephalon the proje ... | 1996 | 9123999 |
| distribution of cholecystokinin-8-like immunoreactivity in the frog brain and spinal cord. | the distribution of cholecystokinin-8 (cck8) containing structures in the central nervous system of the frog (rana esculenta) was investigated with the aid of the peroxidase immunohistochemical method. in the forebrain, immunoreactive perikarya were found in the main olfactory bulb, septum, amygdala, and ventromedial thalamic nuclei. networks of immunoreactive varicose fibers were observed in the septum, the basal area, and the infundibulum, and fiber bundles were found in the marginal and axial ... | 1996 | 9124005 |
| c-fos- and c-jun-like mrna expression in frog (rana esculenta) testis during the annual reproductive cycle. | the expression of c-fos and c-jun mrna has been examined in the testis of a seasonal breeder (the frog, rana esculenta) during the annual reproductive cycle, using northern blot analysis along with measurements of plasma levels of estradiol-17 beta and androgens (testosterone + 5 alpha-dihydrotestosterone). a c-fos-like transcript of 1.9 kb was revealed using a 1.1-kb v-fos probe, while three different transcripts of 3.7, 3.4, and 2.7 kb were seen using 1.0-kb human (h)-c-jun fragment. the proto ... | 1997 | 9126462 |
| is resting state hco3- secretion in frog gastric fundus mucosa mediated by apical cl(-)-hco3- exchange? | 1. we have tested the widely accepted hypothesis that resting-state bicarbonate secretion of gastric fundus mucosa is mediated by cl(-)-hco3- exchange in the apical membrane of surface epithelial cells (secs). to this end, secs of isolated fundus mucosa of rana esculenta were punctured with double-barrelled microelectrodes to measure intracellular ph (phi). 2. no significant phi changes were observed in response to changing luminal hco3- and/or cl- concentrations. the change in phi (delta phi) i ... | 1997 | 9130171 |
| 17 beta-estradiol effects on mast cell number and spermatogonial mitotic index in the testis of the frog, rana esculenta. | estrogen affects mast cell activity and cellular proliferation in several vertebrate tissues. due to the presence of mast cells in the interstitial tissue of the testis and due to the annual changes of spermatogonial proliferation and estradiol level in the frog, rana esculenta, we have studied the possible regulation of mast cell number (mcn) and primary spermatogonial mitosis exerted by 17 beta-estradiol (e2). mcn changed in the testis during the annual reproductive cycle, showing peaks in dec ... | 1997 | 9143141 |
| the h+ pump in frog skin (rana esculenta): identification and localization of a v-atpase. | we here report on studies on the frog skin epithelium to identify the nature of its excretory h+ pump by comparing transport studies, using inhibitors highly specific for v-atpases, with results from immunocytochemistry using v-atpase-directed antibodies. bafilomycin a1 (10 microm) blocked h+ excretion (69 +/- 8% inhibition) and therefore na+ absorption (61 +/- 17% inhibition after 60 min application, n = 6) in open-circuited skins bathed on their apical side with a 1 mm na2so4 solution, "low-na ... | 1997 | 9151653 |
| ultrastructure of the isthmic nucleus and identification of the synaptic contacts received by the neurons of the crossed isthmotectal projection in rana esculenta. | the isthmic nucleus receives its major input from the ipsilateral optic tectum and projects to both tecta. it has been regarded as a relay station that is not involved in further processing of visual information. recent studies on the connectivity and neurochemistry of this nucleus yielded substantial new data suggesting a more important role as being a simple relay. since data on the ultrastructure of this nucleus are scarce the aim of this study was to obtain further information about the syna ... | 1997 | 9176728 |
| regional variations in electrical and ion transport properties along the isolated intestine of the frog rana esculenta. | anterior, posterior and colon regions of isolated intestines of the frog rana esculenta were studied in ussing chambers under short-circuit conditions. each region presented a serosa-positive potential which decreased upon longer incubation with no significant change in resistance. the colon displayed higher transepithelial potential (initial mean: 11.4 mv) and resistance (165.cm 2) than the proximal parts (initial mean: ca. 2 mv and 120-80 .cm 2). bilateral substitution of na+ by nmdg (n-methyl ... | 1997 | 9224546 |
| [gene diffusion in hybrid populations of green frogs rana esculenta l., 1758 complex (amphibia, ranidae) from the dnepr basin]. | population-genetic analysis of hybrid populations of green frogs from the dnepr basin demonstrated limited gene introgression in diploid hybrids in addition to semiclonal reproduction, which is typical for rana esculenta hybrids. introgression is largely confined to the ldh-b locus: the gene of r. lessonae is introduced into the r. ridibunda genome. this phenomenon is unstable as it is geographically restricted and absent in populations of the e-l type. | 1997 | 9244766 |
| presence of angiotensin converting enzyme (ace) activity in serum of amphibian: comparison with ace activity of mammalian serum. | the occurrence of angiotensin converting enzyme (ec 3.4.15.1; ace) was demonstrated for the first time in serum of newt (triturus carnifex) and frog (rana esculenta). the enzymatic activity was evidenced following hydrolysis of n-[3-(2-furyl) acryloyl]l-phenylalanyl glycyl glycine (fapgg), a synthetic substrate of ace. the serum enzyme liberated n-[3-(2-furyl) acryloyl]l-phenylalanine (fap) from fapgg. the properties of the amphibian serum enzymes were compared with those of swine. the amphibian ... | 1997 | 9246391 |
| coexistence of alpha1 and beta adrenergic receptors in the liver of the frog rana esculenta, the toad bufo bufo, the lizard podarcis sicula campestris, and the turtle pseudemys picta elegans. | in mammals and birds the characteristics of alpha1 adrenergic receptors and their biological role in liver metabolism have been clearly described, although the predominance of receptor subtypes varies with species. in contrast, the actual presence of hepatic alpha1 adrenergic receptors in fish, amphibians, and reptiles has been questioned. only recently has their existence been demonstrated in some fish species and also in the wood frog rana sylvatica. the present study assessed the presence of ... | 1997 | 9268616 |
| genomes of two water frog species resist germ line exclusion in interspecies hybrids. | abundant natural interspecies hybrids between the european water frog rana ridibunda and at least three other taxa reproduce hemiclonally, by hybridogenesis: the non-ridibunda genome is excluded in the germ line before meiosis, and the unrecombined ridibunda genome is transmitted to haploid gametes. in contrast, natural hybrids between rana ridibunda and either of two balkan species (rana shqiperica and rana epeirotica) do not show such genome exclusion. this plausibly results from failure of ba ... | 1997 | 9293641 |
| correlation between transepithelial na+ transport and transepithelial water movement across isolated frog skin (rana esculenta). | in the present work the coupling under short-circuited conditions between the net na(+)-influx across isolated frog skin and the transepithelial transport of water was examined i.e., the short-circuit current (isc) and the transepithelial water movement (tewm) were measured simultaneously. it has been shown repeatedly that the isc across isolated frog skin is equal to the net transepithelial na+ transport. furthermore the coupling between transepithelial uptake of nacl under open-circuit conditi ... | 1997 | 9309211 |
| projections from the nucleus isthmi to the visual and auditory centres in the frog, rana esculenta. | the lectin phaseolus vulgaris leucoagglutinin was injected into the nucleus isthmi (ni) in order to study its anterograde and retrograde projections in the frog. the following areas of termination could be discerned in the brainstem: (1) each of the five subnuclei of the torus semicircularis (tos) received fibres from the ni. the projection was the most extensive on the three main subnuclei which disclosed also retrogradely labelled neurones on the side of injections. the subependymal subnuclei ... | 1997 | 9350500 |
| independent responsiveness of frog liver low-density lipoprotein receptor and hmgcoa reductase to estrogen treatment. | cholesterol metabolism in the female frog exhibits circannual modifications which parallel plasma estrogen fluctuations. estrogens enhance production and lipidation of the yolk precursor vitellogenin by inducing the transcription of its gene and by stimulating the activity of 3-hydroxy-3-methylglutaryl coenzyme a (hmgcoa) reductase. the time dependence of the effects that these hormones have on hmgcoa reductase and the low-density lipoprotein (ldl) receptor in the liver of rana esculenta complex ... | 1997 | 9359909 |
| endocardial endothelium in the avascular heart of the frog: morphology and role of nitric oxide. | endocardial endothelial morphology and the physiological modulatory role of nitric oxide (no) were studied in an in vitro preparation of the working intact heart of the frog rana esculenta, which lacks coronary vasculature and is thus devoid of a coronary vascular endothelium. en face confocal scanning laser microscopy of samples of perfused fixed hearts demonstrated the presence of no synthase as a cytoplasmic constituent of the endocardial endothelial cells. stroke volume (as a measure of perf ... | 1997 | 9364019 |
| effect of glucocorticoids on the synthesis of antimicrobial peptides in amphibian skin. | gene-encoded peptide antibiotics are widespread in insects, plants and vertebrates and confer protection against bacterial and fungal infections. nf-kappab is an important transcription factor for many immunity-related mammalian proteins and also for insect immune genes. the activity of nf-kappab is regulated by the interaction with an inhibitor, i kappab. it was recently demonstrated that glucocorticoids induce the synthesis of i kappab in human cell lines. so far, all genes for peptide antibio ... | 1997 | 9373168 |
| distribution of nadph-diaphorase activity in the hypothalamo-hypophysial system of the frog, rana esculenta. | using nicotinamide adenine dinucleotide phosphate (nadph)-diaphorase (nd) histochemistry, this study reports a wide distribution of nd activity in the hypothalamus, and for the first time in the median eminence (me), the neural lobe (nl) and in the pars distalis (pd) of the frog, rana esculenta. perikarya are nd-active within the nucleus preopticus (npo), the nucleus preopticus periventricularis (npp), located around the preoptic recess (pr), the suprachiasmatic nucleus (scn) and within five inf ... | 1997 | 9389596 |
| l-alanine uptake by frog (rana esculenta) red blood cells. | l-alanine uptake has been studied in frog red blood cells. the present study shows the presence of different carriers for this amino acid in these cells. in the physiological concentration range, most l-alanine is taken up through the na(+)-dependent system asc, although the sodium-independent systems asc and l are also active. the competitive inhibition data obtained makes difficult to differentiate the two na(+)-independent activities in a clear contrast with data from fish or mammalian erythr ... | 1997 | 9406440 |
| rana esculenta l. liver fru-1,6-p2ase and g-6-pase activity and fru-2,6-p2 concentration after acclimation at 5 and 25 degrees c. | the activities of fru-1,6-p2ase and g-6-pase in liver and kidney of frogs acclimated at 5 and 25 degrees c and fru-2,6-p2 level in liver were investigated. the aim of this study was to examine the effect of thermal acclimation on regulatory enzymes of gluconeogenesis and on concentration of gluconeogenesis regulator. fru-1,6-p2ase activity in liver of frogs acclimated at 5 degrees c was 6.16 +/- 0.77 and 4.46 +/- 0.46 u/g wt in those acclimated at 25 degrees c; the respective values for g-6-pase ... | 1997 | 9406446 |
| asymmetry in the left and right habenulo-interpeduncular tracts in the frog. | in the frog rana esculenta the left dorsal habenula includes a lateral and a medial component, whereas the right dorsal habenula is only represented by one nucleus. the efferents of the habenular nuclei to the interpeduncular nucleus were herein investigated with the retrograde horseradish peroxidase tracing. injections of cobaltic-lysine complex in the interpeduncular nucleus were also performed. intensely labeled fibers of the fasciculus retroflexus on the right and left sides of the brain wer ... | 1998 | 9434210 |
| different modulation of steroidogenesis and prostaglandin production in frog ovary in vitro by ace and ang ii. | our aim was to study the role of angiotensin-converting enzyme (ace) and angiotensin ii (ang ii) on ovarian steroidogenesis and prostaglandin production of amphibian. hormonal effects of ace, ace inhibitors, synthetic bullfrog angiotensin i (ang i), and [val5]ang ii were compared on frog ovaries of postreproductive and prereproductive periods. very high ace activity was found in ovary of water frog (rana esculenta) compared with other frog tissues, and this activity was inhibited by the typical ... | 1997 | 9435665 |
| lens fibre transdifferentiation in cultured larval xenopus laevis outer cornea under the influence of neural retina-conditioned medium. | the outer cornea of larval xenopus laevis can reprogram cell differentiation when cultured in medium conditioned by x. laevis neural retina (xrcm) or by rana esculenta neural retina (rrcm). under these experimental conditions corneal cells showed the same series of cytological changes of fibre cell differentiation observed during ontogenesis and in vivo lens regeneration: enlargement of nuclei and nucleoli, increase of ribosomal population (cytoplasm-basophilia), cell elongation gradual loss of ... | 1997 | 9447244 |
| large retinal ganglion cells that form independent, regular mosaics in the ranid frogs rana esculenta and rana pipiens. | population-based studies of ganglion cells in retinal flatmounts have helped to reveal some of their natural types in mammals, teleost fish and, recently, the aquatic mesobatrachian frog xenopus laevis. here, ganglion cells of the semiterrestrial neobatrachian frogs rana esculenta and rana pipiens have been studied similarly. ganglion cells with large somata and thick dendrites could again be divided into three mosaic-forming types with distinctive stratification patterns. cell dimensions correl ... | 1997 | 9447692 |
| dissecting the frog inner ear with gaussian noise. i. application of high-order wiener-kernel analysis. | wiener kernel analysis was used to characterize the auditory pathway from tympanic membrane to single primary auditory nerve fibers in the european edible frog, rana esculenta. nerve fiber signals were recorded in response to white gaussian noise. by cross-correlating the noise stimulus and the nerve fiber response, we computed (1) the full second-order wiener kernel, and (2) the diagonals of the zeroth- to fourth-order wiener kernels. these diagonals are usually referred to as polynomial correl ... | 1997 | 9447936 |
| dissecting the frog inner ear with gaussian noise. ii. temperature dependence of inner ear function. | the temperature dependence of the response of single primary auditory nerve fibers (n = 31) was investigated in the european edible frog, rana esculenta (seven ears). nerve fiber responses were analyzed with wiener kernel analysis and polynomial correlation. the responses were described with a cascade model, consisting of a linear bandpass filter, a static nonlinearity, and a linear lowpass filter. from the computed wiener kernels and the polynomial correlation functions, the characteristics of ... | 1997 | 9447937 |
| quantitative analysis of anaerobic metabolism in resting anoxic muscle by 31p and 1h mrs. | 31p and 1h mrs high resolution measurements at 4.7 t were carried out in isolated frog (rana esculenta) gastrocnemius muscle during anoxia to assess, using reference compounds, the concentration of high energy phosphates (approximately p = phosphocreatine (pc) plus adenosinetriphosphate (atp)), inorganic phosphate (p(i)), phosphomonoesters (pme) and lactate (la): two sets of measurements were performed, with (p) and without (up) muscle iaa poisoning and the time course of the metabolite concentr ... | 1997 | 9452766 |
| cytochemical evidence for potassium-dependent p-nitrophenylphosphatase activity in pavement cells of rana esculenta mesentery. | we previously reported that during hibernation in rana esculenta, various organs (i.e., skin, urinary bladder, kidney) change their osmoregulatory activity. here, we considered the possible role of the frog mesentery in the ion transport, evaluating morphological and cytochemical (k+-p-nitrophenylphosphatase activity) aspects. | 1998 | 9458062 |
| crossbridge viscosity in activated frog muscle fibres. | force responses to fast ramp stretches at various velocities were recorded in single muscle fibres isolated from tibialis anterior muscle of the frog (rana esculenta) at a sarcomere length between 2.15 and 3.25 microns at 15 degrees c. stretches were applied at the tetanus plateau and during tetanus rise. length changes were recorded at the sarcomere level using either a laser diffractometer or a striation follower apparatus. the immediate force response to the stretch is not simply elastic, as ... | 1997 | 9468605 |
| gonadotropins and reproductive function in the anuran amphibian, rana esculenta. | in this study, the measurement both of peripheral gonadotropins (fsh and lh) and of sex steroids in male and female wild anuran, rana esculenta, was performed during the annual reproductive cycle; moreover, the role of gonadotropins in the vitellogenic process and in ovarian steroidogenesis was investigated through in vitro experiments. lh plasma changes in males showed high values during autumn-winter months and during the mating period, when high androgen levels were found. conversely, for the ... | 1998 | 9472927 |
| force responses to fast ramp stretches in stimulated frog skeletal muscle fibres. | force responses to fast ramp stretches at various velocities were recorded from single muscle fibres isolated from either lumbricalis digiti iv or tibialis anterior muscle of the frog (rana esculenta) at sarcomere length between 2.15 and 3.25 microns at 15 degrees c. stretches were applied at rest, at tetanus plateau and during the tetanus rise. stretches with the same velocity but different accelerations were imposed to the fibre to evaluate the effect of fibre inertia on the force responses. l ... | 1998 | 9477375 |
| wiener kernel analysis of a noise-evoked otoacoustic emission. | in one specimen of the frog species, rana esculenta, the following were measured: (1) a spontaneous otoacoustic emission; (2) a click-evoked otoacoustic emissions; and (3) a noise evoked otoacoustic emission. from the noise evoked emission response, a first- and a second-order wiener kernel and the first six polynomial correlation functions were calculated by cross-correlating the stimulus and response signals. a peak near 850 hz was visible in the spontaneous otoacoustic emission, the click-evo ... | 1997 | 9478290 |
| in situ characterization of mast cells in the frog rana esculenta. | the number, distribution, and ultrastructural characteristics of mast cells were assessed in the tongue, heart, and kidney of the frog rana esculenta. the density of tongue mast cells (253+/-45 mast cells/mm2) was significantly higher than that of the heart (5.3+/-0. 4/mm2) and kidney (15.3+/-1.4 /mm2). a striking feature of this study was the remarkable association of frog mast cells to nerves. the ultrastructural study of the mast cell/nerve association demonstrated that mast cells were closel ... | 1998 | 9506923 |
| calretinin-immunoreactive elements in the retina and optic tectum of the frog, rana esculenta. | the frog retina contains numerous 28 kda calbindin positive elements in its every layer. at the same time, parvalbumin has been observed only in a few elements in the visual system of amphibian species, whilst calretinin immunoreactivity could be detected in salamander retina and the optic tectum of tench. however, the presence and distribution of calretinin have been described to date neither in the retina nor in the other parts of the visual system of anurans. therefore, the aim of this study ... | 1998 | 9519249 |
| distribution of somatostatin-like immunoreactivity in the brain of the frog, rana esculenta, during development. | the anatomical distribution of somatostatin-like immunoreactivity in the central nervous system of the frog, rana esculenta, during development and in juvenile specimens was investigated by indirect immunofluorescence. soon after hatching, at stages ii-iii, somatostatin-like immunoreactive structures were found in the preoptic-median eminence complex. in stage vi tadpoles, new groups of immunopositive perikarya and nerve fibers appeared in the diencephalon, within the ventral infundibular nucleu ... | 1998 | 9554935 |
| nitric oxide production by cells infiltrating amphibian skin grafts. | in vivo injection of the edible frog rana esculenta with nos inhibitor, l-nmma caused prolongation of skin allograft and xenograft viability, statistically significant only in the latter case. in the present studies skin allo- and xenografts at the latent or rejection phase were excised from the hosts (bufo bufo, r. temporaria, and r. esculenta) and incubated in vitro for 24 hrs in a medium only or in the presence of competitive (l-nmma, l-name, l-aminoguanidyne) and noncompetitive (dexamethason ... | 1997 | 9557139 |
| receptor-mediated activation of g-proteins by kappa opioid agonists in frog (rana esculenta) brain membranes. | this study delineates the heterotrimeric guanine nucleotide binding regulatory protein (g-protein) types in frog (rana esculenta) brain membranes and their activation by kappa opioid agonists. ethylketocyclazocine (ekc), trans-(+/-)-3,4-dichloro-n-methyl-n-(2-[1-pyrrolidinyl]cyclohexyl)b enzeneacetamide (u-50,488) and bremazocine displayed dose-dependent, norbinaltorphimine-reversible stimulation of guanosine-5'-o-(3-[35s]thio)triphosphate ([35s]gtpgammas) binding in crude membrane preparations. ... | 1998 | 9570716 |
| temperature but not season affects the transplantation immunity of anuran amphibians. | the effects of ambient temperature (22 degrees c/10 degrees c) and season (summer/winter) on anuran skin allograft and xenograft rejection was tested in frogs (rana temporaria and r. esculenta) and toads (bufo bufo, bombina variegata, and bombina bombina). mean graft survival times were significantly prolonged at the low temperature in a species-specific manner, the edible frog (r. esculenta) being the most sensitive and the common toad (bufo bufo) relatively resistant. allografts were more temp ... | 1998 | 9571769 |
| affinity labelling of frog brain opioid receptors by dynorphin(1-10) chloromethyl ketone. | it has been previously found that chloromethyl ketone derivatives of enkephalins bind irreversibly to the opioid receptors in vitro. recently a novel affinity reagent, tyr-gly-gly-phe-leu-arg-arg-ile-arg-pro-gly chloromethyl ketone (dynorphin(1-10)-gly11 chloromethyl ketone, dyncmk) was synthesized, and its binding characteristics to frog (rana esculenta) brain membranes were evaluated. in competition experiments, the product shows a relatively high affinity for the kappa-opioid binding sites la ... | 1997 | 9574838 |
| cyclosporin a stimulates na+ transport across the isolated skin of rana esculenta. | cyclosporin a (cs a), added to the fluid bathing the internal surface of the isolated skin of rana esculenta, increased short-circuit current (scc) with a maximal effect at 5 microm. this effect was completely inhibited by amiloride (0.2 mm in the fluid bathing the external surface). by measuring both transepithelial fluxes of 22na+ across symmetrical parts of the short circuited skin, cs a was found to increase the net absorption of na+. naproxen (10 microm), a cyclooxygenase inhibitor, decreas ... | 1997 | 9587652 |
| [effects of drugs on re-excitability of synapses of isolated frog ganglia]. | effects of different pharmacons on the non-excitable period (nep) and on the relative excitable period (rep) was studied in the sympathetic ganglionic synapses of the frog (rana esculenta). using paired stimulation we demonstrated that hexamethonium, magnesium, pempidine, tetraethylammonium (tea) and d-tubocurarine chlorides significantly prolonged both nep and rep at ganglion blocking threshold concentrations. their maximum effect occurred within 30-60 min after the start of the exposition. hem ... | 1996 | 9604492 |
| aromatase and testosterone receptor in the liver of the female green frog, rana esculenta. | in the green frog, rana esculenta, a peculiar feature of female reproductive endocrinology is an high level of circulating testosterone. although several hypotheses have been set out to explain this phenomenon, the testosterone specific roles in female anuran have not been yet fully explored. this study results propose a testosterone implication in liver vitellogenin synthesis control, since in ovariectomized frogs the hormone induces an increase of circulating vitellogenin. the testosterone act ... | 1998 | 9619844 |
| proopiomelanocortin gene expression in the ovary of the frog, rana esculenta. | 1998 | 9629163 | |
| beta-endorphin binding sites in pars distalis of the frog, rana esculenta. | 1998 | 9629207 | |
| prolactin and stress response in frog rana esculenta. | 1998 | 9629230 | |
| organization of atrial natriuretic factor-like immunoreactive system in the brain of the frog rana esculenta during development. | immunocytochemical distribution of the atrial natriuretic factor (anf) has been studied in the brain and pituitary of the anuran rana esculenta during development and in juvenile animals. using human anf and rat alpha-anf antisera, immunoreactive cell bodies and nerve fibers were revealed in stage ii-iii tadpoles and in successive larval stages. soon after hatching, stages ii-iii, the anf-like-immunoreactive elements were confined to the preoptic area-median eminence complex. during successive s ... | 1998 | 9634597 |
| ultrastructural and functional study of the liver pigment cells from rana esculenta l. | a study of the liver pigment cells of rana esculenta l. has been performed on both liver in toto and cells in culture. ultrastructural and cytochemical analyses showed a close relationship between this visceral pigment cell system and the cells of hepatic macrophage lineage. like the latter, the liver pigment cells present phagocytic activity, in the sinusoids and in vitro, and give a positive response to tests for peroxidase and lipase. the liver pigment cells are isolated, together with the ku ... | 1998 | 9639102 |
| patch clamp on the luminal membrane of exocrine gland acini from frog skin (rana esculenta) reveals the presence of cystic fibrosis transmembrane conductance regulator-like cl- channels activated by cyclic amp. | chloride channels in the luminal membrane of exocrine gland acini from frog skin (rana esculenta) constituted a single homogeneous population. in cell-attached patches, channels activated upon exposure to isoproterenol, forskolin, or dibutyryl-camp and isobutyl-1-methyl-xanthine rectified in the outward direction with a conductance of 10.0 +/- 0.4 ps for outgoing currents. channels in stimulated cells reversed at 0 mv applied potential, whereas channels in unstimulated cells reversed at depolari ... | 1998 | 9649581 |
| role of nitric oxide in gonadotropin-releasing hormone-dependent prostaglandin f2 alpha synthesis by frog (rana esculenta) interrenal gland during post-reproduction. | the aim of this study was to clarify the possible involvement of nitric oxide (no) on prostaglandin (pg) e2-9-ketoreductase activity in the gonadotropin-releasing hormone (gnrh)-dependent pgf2 alpha synthesis by the interrenal gland of the female water frog, rana esculenta, during the post-reproduction. interrenal glands were incubated in vitro with gnrh, no donor (sodium nitroprusside, snp), and inhibitors of phospholipase c (compound 48/80), inositol triphosphate (decavanadate), calmodulin (ca ... | 1998 | 9653767 |
| d-aspartic acid is implicated in the control of testosterone production by the vertebrate gonad. studies on the female green frog, rana esculenta. | in the present study we report the occurrence of d-aspartic acid (d-asp) in the ovary of the green frog rana esculenta and its putative involvement in testosterone production by the gonad. in the ovary, d-asp concentrations undergo significant variations during the main phases of the sexual cycle. in spawning females (march), its concentration was low (2.5 +/- 1.1 nmol/g ovary) and during the post-reproductive period (june) it increased and reached its peak level (58.0 +/- 10.1 nmol/g) in octobe ... | 1998 | 9659282 |
| nitric oxide mediates gonadotropin-releasing hormone effects on frog pituitary. | we studied the possible role of nitric oxide (no) in gnrh-induced gonadotropin secretion in the female water frog, rana esculenta. during pre-reproduction, pre-ovulation, ovulation, post-ovulation, refractory, recovery and hibernation, pituitaries were incubated with medium-alone, gnrh, no donor (nod), no synthase inhibitor (nosi), cyclic gmp analogue (cgmpa), soluble guanylate cyclase inhibitor (sgci), gnrh plus nosi, gnrh plus sgci, and nod plus sgci. because antisera raised against gonadotrop ... | 1998 | 9688343 |
| effects of aminoperimidine on electrolyte transport across amphibian skin. | the effect of aminoperimidine (ap) on transepithelial na+ transport and cl- conductance (g(cl)) of isolated amphibian skin (bufo viridis and rana esculenta) was analyzed using transepithelial and intracellular electrophysiological techniques. ap, applied at concentrations between 30 and 100 microm from the mucosal side, stimulated na+ transport rapidly and reversibly by more than 30% of the control value due to an increase in apical membrane na+ permeability. influence of ap on basolateral membr ... | 1998 | 9694348 |
| action of physalaemin on the ionic transport across the frog skin. | the effects of the non-mammalian tachykinin physalaemin were studied on the short circuit current (scc) and on both influx (ji) and outflux (jo) of 36cl- and 22na+ across the isolated skin of rana esculenta. physalaemin, added to the internal bathing fluid, increased scc in a dose-dependent manner with a maximal effect at 1 microm. this increase was due to a stimulation of both na+ absorption and cl- secretion. bumetanide (20 microm in the internal fluid), an inhibitor of the na+/k+/2cl- cotrans ... | 1998 | 9711352 |
| immunocytochemical changes of cytoskeleton components and calmodulin in the frog cerebellum and optic tectum during hibernation. | during hibernation, variation in the metabolism of nerve cells occurs. since the cytoskeleton plays an important role in nerve cell function, we have analyzed the immunocytochemical expression of two cytoskeleton components, i.e. phosphorylated 200 kda neurofilament protein, and microtubule-associated protein 2 in the cerebellum and optic tectum of hibernating frogs (rana esculenta) in comparison with active animals. in addition, we have considered the immunocytochemical expression of calmodulin ... | 1998 | 9719360 |
| comparison of european systemic piscine and amphibian iridoviruses with epizootic haematopoietic necrosis virus and frog virus 3. | iridovirus-like agents isolated from systemic infected fish (silurus glanis, sfir; ictalurus melas, cfir i, cfir ii, cfir iii) and from frogs (rana esculenta, reir) in europe, epizootic haematopoietic necrosis virus (ehnv) isolated in australia from redfin perch (perca fluviatilis), and frog virus 3 (fv 3) isolated from frogs (rana pipiens) in the usa were investigated by electron microscopy, polypeptide composition, immunofluorescence, restriction endonuclease digestion, southern-blot hybridiza ... | 1998 | 9719770 |
| ultracytochemical localization of guanylate cyclase after stimulation with natriuretic peptides in frog choroid plexus. | the ultracytochemical localization of particulate guanylate cyclase (gc) has been studied in rana esculenta choroid plexus after activation with rat atrial natriuretic peptide (anp), porcine brain natriuretic peptide (bnp) and porcine c-type natriuretic peptide (cnp). this study shows that the three peptides are activators of gc in the choroid plexus as demonstrated by the presence of reaction products at the level of the epithelium and sinusoids. in the apical zone of the epithelial cells predo ... | 1998 | 9723195 |
| structure-activity analysis of brevinin 1e amide, an antimicrobial peptide from rana esculenta. | brevinin 1e, consisting of 24 amino acid residues, from rana esculenta has potent antimicrobial and hemolytic activity. from a structural point of view, this peptide has a n-terminal hydrophobic region, a proline hinge region in the middle and a c-terminal loop region delineated by an intra-disulfide bridge, which is a common structural feature of antimicrobial peptides from rana species. to investigate the structural features for antimicrobial and hemolytic activity, truncated and linearized br ... | 1998 | 9748603 |
| alkaline secretion by frog gastric glands measured with ph microelectrodes in the gland lumen. | 1. in the present work we have measured the ph of the secreted fluid within the gland lumen of isolated but intact gastric mucosa of rana esculenta. tissues were mounted in a double chamber allowing continuous perfusion of the mucosal and serosal compartment, and the measurements were made with double-barrelled ph glass microelectrodes inserted into the glands from the serosal surface under microscopic inspection. 2. during inhibition of h+ secretion by cimetidine (100 microm) the luminal gland ... | 1998 | 9782173 |
| ranatuerins: antimicrobial peptides isolated from the skin of the american bullfrog, rana catesbeiana. | nine peptides, termed ranatuerins 1-9, with antimicrobial activity towards staphylococcus aureus, were isolated from an extract of the skin of the adult american bullfrog, rana catesbeiana. in common with other cytolytic peptides from ranid frogs, (e.g. ranalexin, gaegurins, brevinins), ranatuerins 1 and 4 contain an intramolecular disulfide bridge forming a heptapeptide ring whereas in ranatuerins 2 and 3 the disulfide bridge forms a hexapeptide ring. the structurally related ranatuerins 5-9 co ... | 1998 | 9784389 |
| apolipoproteins and their electrophoretic pattern throughout the reproductive cycle in the green frog rana esculenta. | lipoprotein fractions in rana esculenta were separated using the same salt intervals currently applied for human lipoproteins. very low density lipoproteins (vldl), low density lipoproteins (ldl) and high density lipoproteins (hdl) were analyzed with reference to the electrophoretic pattern. the lipoprotein electrophoretic pattern in males and females throughout the reproductive cycle showed minor differences. in general, each fraction was characterized by a specific apolipoprotein content. vldl ... | 1998 | 9787759 |
| experimental infections of rana esculenta with aeromonas hydrophila: a molecular mechanism for the control of the normal flora. | frogs can be useful models for studying the mechanisms that may regulate their natural microbial flora. their skin glands produce a secretion containing 20-30 different peptides, some antimicrobial some neurotrophic. as they often live in soil or silt that is rich in microbes, they can be expected to be able to prevent or eliminate infections in very short periods of time. the bacterium aeromonas hydrophila is widely distributed in nature and is considered as part of the natural flora of frogs a ... | 1998 | 9790305 |
| estrogen stimulates intracellular traffic in the liver of rana esculenta complex by modifying rab protein content. | during vitellogenesis in oviparous animals, estrogens induce the synthesis of the yolk precursor vitellogenin, a lipophosphoprotein rich in cholesterol. estrogens also induce the activity of 3-hydroxy-3-methylglutaryl coa reductase, that is necessary for the lipidation of vitellogenin. this increased enzyme activity could also be important for the production of isoprenoid groups that post-translationally modify proteins such as the rab proteins, which are small g proteins involved in intracellul ... | 1998 | 9790951 |
| [precise dna cytometry: investigation of individual variability in animal genome size]. | the variability of genome size was studied in animal populations and in cell populations of different animal species by means of dna flow cytometry with the precision level of several tenths of percent. for populations of frog rana esculenta and laboratory mouse lines c57b1 and cba the analysis was made with cells of different tissues: erythrocytes for r. esculenta, splenocytes for mice and haploid cells of testes for both species. the results of dna cytometry, obtained with cells of different s ... | 1998 | 9821251 |
| tsh and thyroid hormones induce the release of secretory granules in the harderian gland of hypophysectomized frogs, (rana esculenta): morphological observations. | the secretory activity of the harderian gland (hg) in the frog rana esculenta is influenced by pituitary and thyroid hormones. administration of thyroid stimulating hormone (tsh), t3 and t4 to hypophysectomized male and female frogs, affects the release of secretory granules in the lumina of glandular acini. in particular, treatment with t3 radically modified morphological parameters (height and area of acinar lumina of the glandular cells); t4 or tsh had less effect. administration of thiouraci ... | 1998 | 9827054 |
| olfactory receptors in aquatic and terrestrial vertebrates. | in species representing different levels of vertebrate evolution, olfactory receptor genes have been identified by molecular cloning techniques. comparing the deduced amino-acid sequences revealed that the olfactory receptor gene family of rana esculenta resembles that of xenopus laevis, indicating that amphibians in general may comprise two classes of olfactory receptors. whereas teleost fish, including the goldfish carassius auratus, possess only class i receptors, the 'living fossil' latimeri ... | 1998 | 9839455 |
| comparative analysis of gnrh neuronal systems in the amphibian brain. | we have investigated the gnrh-ir neuronal systems in the brain of the oviparous urodele, triturus vulgaris, ovoviviparous urodele, salamandra salamandra, and viviparous caecilian, typhlonectes compressicauda, and have reexamined xenopus laevis, ambystoma mexicanum, and rana esculenta. results showed that mgnrh neuronal system was diffused along the medioventral telencephalon and diencephalon with the numerical preponderance of gnrh cell bodies in the rostral mediobasal telencephalon in t. vulgar ... | 1998 | 9843639 |
| antimicrobial peptides of the brevinin-2 family isolated from gastric tissue of the frog, rana esculenta. | four structurally related peptides with potent growth-inhibitory activity towards escherichia coli were isolated from an extract of the stomach of the european green frog rana esculenta, and were identified as members of the brevinin-2 family. two peptides, termed brevinin-2eg (gimdtlknla10 ktagkgalqs20 llnhasck ls30gqc) and brevinin-2eh (gimdtlknla10 ktagkgalqs20 llnhasckl s30 kqc) have not been described previously. one peptide is identical to brevinin-2ec, previously isolated from r. esculent ... | 1998 | 9918774 |
| nadph-diaphorase-positive neurons and pathways in the brain of the frog rana esculenta. | we described the nadph-diaphorase-containing neurons and fibres in the brain of the frog rana esculenta. in the telencephalon stained cells occurred in the olfactory bulb, all subdivisions of the pallium, the diagonal band, the medial septum and the striatum. the olfactory glomeruli showed the most intense enzyme reaction. the neuropil of the accessory olfactory bulb was also heavily stained and this staining extended to the rostral diencephalon through the ventral lateral pallium. fibre stainin ... | 1999 | 9930624 |