Publications

localization of calcium in fibrocytes associated with the "substantia amorpha" in the skin of toad, bufo bufo (l.) (amphibia, anura).	using the potassium pyroantimonate-technique in the fibrocytes associated with the calcium-containing granules of the substantia amorpha within the dermis of bufo bufo numerous electron-dense deposits have been observed. reaction product lies in the mitochondria, at the plasma membranes and in various vesicular structures. x-ray microanalysis confirmed that pyroantimonate was predominantly associated with calcium. it is suggested that certain organelles of the fibrocytes are capable of sequester ...	1982	6179122
the nature of urea transport across the luminal membrane of bufo bufo urinary bladder.	by using the washing-out technique, counterflow acceleration for urea was demonstrated on the luminal membrane of bufo bufo urinary bladder, in the absence of adh. this phenomenon completely disappears in the presence of phloretin 10-4 m on the luminal side and is consistent with the presence of a mobile carrier mechanism for urea transport across the luminal membrane, in basal conditions. in the presence of adh, counterflow acceleration is completely absent. this result is in agreement with the ...	1982	6182852
[experimental study of larval myelogenesis in the central nervous system of bufo bufo].		1982	6185101
the influence of acth fragments on habituation of the prey catching behaviour in the european toad (bufo bufo l.).	earlier observations on the influence of the acth molecule on habituation in toads revealed a capacity, which resembles the improvement of learning and memory processes in rats [6]. in the present investigation acth, acth1-10 and acth11-24 were tested on habituation of turning reaction, a stereotypic component of the prey catching behaviour in the european toad, bufo bufo l.. furthermore the time relationship of the acth-effect was determined by injections at different times prior to the beginni ...	1982	6281825
developmental aspects of hexose metabolism in bufo bufo.	due to the close correlation between glucose mobilization and utilization within animal tissues, in this paper, the stages of appearance of phosphorylase, glucose-6-phosphatase and hexokinase as well as the levels of some intermediates of glucose metabolism have been investigated during bufo bufo development. phosphorylase first appears at stage 13 and is dominant in the neural part of the embryo, but, after this stage, increases relatively more in the nonneural one. hexokinase appears at stage ...	1982	6296268
chloride channels in toad skin.	a study of the voltage and time dependence of a transepithelial cl- current in toad skin (bufo bufo) by the voltage-clamp method leads to the conclusion that potential has a dual role for cl- transport. one is to control the permeability of an apical membrane cl-pathway, the other is to drive cl- ions through this pathway. experimental analysis of the gating kinetics is rendered difficult owing to a contamination of the gated currents by cellular ion redistribution currents. to obtain insight in ...	1982	6130539
question of "head preference" in response to worm-like dummies during prey-capture of toads, bufo bufo.	if a black worm-like dummy is moving against a white background, toads fixate and snap at the leading end of the stimulus. this "head preference" phenomenon is - within limits - independent of (i) background structure, and (ii) stripe length. "head preference" can be disturbed by reducing the amount of the stimulus background contrast as well as by point structures incorporated in the worm-like shape of the stimulus. if the stimulus-background contrast of the worm dummy is reversed, toads exhibi ...	1982	24923495
cell kinetics in the epidermis of the toad bufo bufo bufo (l.) after partial hypophysectomy followed by corticotrophin treatment (an autoradiographic study).	1. cell kinetic parameters in the epidermis of partially hypophysectomized, acth-treated toads whose moulting frequency was increased threefold were studied using labelled thymidine and the autoradiographic technique. 2. the labelling index, length of s-phase and cycle time of stratum germinativum cells changed slowly as a function of the number of acth injections, and so did the migration of cells from stratum germinativum to stratum corneum. 3. a cell production in stratum germinativum of norm ...	1983	6133672
serosal and mucosal facilitated transport of urea in urinary bladder of of bufo bufo: evidence for an alleged water uptake.	in bufo bufo urinary bladder an urea facilitated transport has been localised on the luminal membrane. the transport fulfils the criteria for such a mechanism, i.e. is saturable and is inhibited by phloretin, a specific inhibitor for urea transport. similarly to that of bufo marinus and rana esculenta the luminal membrane of bufo bufo urinary bladder shows an adh stimulated facilitated transport. experiments wtih amphotericin b, serosal phloretin (with and without adh), have demonstrated the pre ...	1983	6135534
[electrotonic transmission between primary afferent fibers and the motor neurons of the isolated spinal cord of various representative amphibians].	studies have been made of monosynaptic excitatory postsynaptic potentials elicited by stimulation of the posterior root in motoneurones of the isolated spinal cord of the frog rana ridibunda, toad bufo bufo, and clawed toad xenopus laevis. in all the amphibians studied, the early component of monosynaptic epsp was not blocked in ca-free medium containing 2 mm mn2+. it is suggested that electrical coupling in anuran amphibians reflects certain stage of evolution of the synaptic transmission in ve ...	1983	6316697
observations on the routes of infection of oswaldocruzia filiformis (nematoda: trichostrongylidae) in amphibia.	the oral, percutaneous and subcutaneous routes of infection of oswaldocruzia filiformis were investigated in amphibia. tadpoles of bufo bufo and rana temporaria can be infected with o. filiformis when kept temporarily in a suspension of infective larvae in water. larval stages and subadults were found in tadpoles. all stages of the parasite, including egg-producing females, were found after metamorphosis of the host. however, under natural circumstances infection of tadpoles seems unlikely. oral ...	1983	6404067
relation between activity of tectal neurons and prey-catching behavior in toads bufo bufo.		1983	6405285
neuronal correlates of edge preference in prey-catching behavior of toads bufo bufo.		1983	6410287
[nature of the products of in vitro interrenal synthesis in adult bufo bufo formosus].	corticosterone (b), aldosterone (aldo), 11-deoxycorticosterone (doc), 11-dehydrocorticosterone (a), 18-hydroxycorticosterone (18 oh b) and cortisol (f) are identified after incubation of interrenal of bufo bufo formosus with radioactive progesterone. yields of radioactive b and aldo are larger than those of radioactive doc, a and 18 oh b; yield of radioactive f is the smallest one.	1983	6414657
cholinergic system in the toad's (bufo bufo l.) visual system.	the brain structures mediating the prey-catching behavior of the toad have been described in earlier studies but none of these studies has identified the transmitter systems in the optic tectum responsible for this behavior. behavioral tests with different test compounds provide evidence that the cells responsible for the orienting, jumping, and snapping behaviors associated with feeding in toads are normally inhibited by cholinergic synapses.	1983	6416249
studies on corticoid action on the toad tadpole tail in vitro.	the effect of adrenal corticoids on the shrinkage of tail segments from bufo bufo japonicus tadpoles was studied in vitro. deoxycorticosterone acetate (dca) was effective in accelerating the shrinkage of tail segments if thyroxine (t4) or triiodothyronine (t3) was present in the medium. the shrinkage caused by dca was dose dependent. in the absence of thyroid hormone, dca did not induce tail resorption. shrinkage of tail segments induced by dca and t4 was blocked by prolactin. among the steroid ...	1983	6421652
ultrastructural localization of immunoreactive calcitonin in the two cell types of the ultimobranchial gland of the common toad (bufo bufo l.).	the ultimobranchial (ub) glands of the common toad bufo bufo consist of several cellular masses containing two quite different cell types which line a central lumen filled with amorphous material. the morphologically defined type i cell is akin to a typical calcitonin secretory cell as observed for all vertebrates, with small dense-core secretory granules. on the contrary the type ii cell displays large apical dense bodies which may be related to the secretion and/or absorption of the amorphous ...	1984	6421654
current-voltage relations of the basolateral membrane in tight amphibian epithelia: use of nystatin to depolarize the apical membrane.	exposure of the mucosal side of toad (bufo bufo) urinary bladder and frog (rana ridibunda) skin to the polyene ionophore nystatin, resulted in stable preparations in which the apical resistance was negligible compared to the basolateral resistance. the preparations support passive k currents in both directions and an amiloride-insensitive na current in the apical-serosal direction which is blocked by ouabain. the nystatin-treated toad bladder was used to study the electrical properties of the ba ...	1984	6422046
in vitro induction of sperm nucleus decondensation by cytosol from mature toad eggs.	an in vitro assay was performed on the cytosol from oocytes of the toad, bufo bufo japonicus, to examine the cytoplasmic activity that induces sperm nucleus decondensation (snd). when the sperm, pretreated for 15 min with 0.05% triton x-100, were incubated in cytosol obtained from mature eggs (18 h post-hormone treatment: pht) 30-60 min after activation, their nuclei elongated and swelled markedly to take a spherical shape between 1 and 2 h after incubation. the treatment of such detergent-treat ...	1984	6427388
visual unit, eeg and sustained potential shift responses in the brains of toads (bufo bufo) during alert and defensive behavior.	cranially mounted differential preamplifiers allowed visual unit activity, eegs and sustained potential shifts to be monitored from the tectum of freely moving toads (bufo bufo). alert behavior was elicited by a moving visual stimulus. movement of the stimulus in the receptive field of a unit elicited its activity and increased the amplitude of the high frequency component of the local eeg, accompanied by a sustained potential shift. when an animal received a "prod" with a perspex rod, defensive ...	1984	6431460
effect of vasopressin on the permeability of nonelectrolytes across the skins of rana esculenta and bufo bufo.		1984	6432008
toad egg-jelly as a source of divalent cations essential for fertilization.	dejellied uterine eggs of the toad bufo bufo japonicus are not fertilizable in 1/20 de boer's solution (1/20 db), but are fertilized when inseminated in a uv-solubilized jelly (uvj) or the dialyzate of uvj (uvjd). the present study was carried out to define this fertilization-supporting activity of egg-jelly. dejellied eggs were fertilized in a high frequency when inseminated in a medium containing the ashes obtained by heating uvjd at 600 degrees c for 16 hr. similarly, a reconstituted salt sol ...	1984	6434358
[the biological composition of the toad (bufo bufo)].		1984	6436839
corticosterone stimulates the development of preoptic catecholamine neurons in tadpoles bufo bufo japonicus.	in bufo bufo japonicus catecholamine neurons in the preoptic recess organ (pro) became detectable at the metamorphic climax by formaldehyde-induced fluorescence (falck-hillarp technique). in hypophysectomized tadpoles metamorphosis was inhibited and no fluorescent neurons appeared in the pro. implantation of a pituitary graft to the hypophysectomized tadpoles induced metamorphosis and development of pro catecholamine neurons. administration of corticosterone to hypophysectomized tadpoles resulte ...	1984	6440455
effects of telencephalic ablation on visual unit, sustained potential shift, and eegs recorded from the toad tectum in response to a visual stimulus.	extracellular recordings were made of visual unit activity, sustained potential shifts (spss), and electroencephalographic activity (eegs) from the optic tectum and of eegs from the telencephalon of immobilized toads (bufo bufo). moving visual stimuli were presented, and the bioelectric responses were monitored both before and after ligature of the telencephalon. the operation reduced the neuronal spike frequency and the amplitude of the tectal sps and eeg responses. eegs were still recorded fro ...	1984	6421296
tubular myelin structures in the lungs of amphibia. the mode of formation.	the lungs of the tree frog hyla arborea and the toad bufo bufo were fixed in glutaraldehyde with the addition of picric acid or tannic acid to visualize tubular myelin (tm), one of the forms of pulmonary surfactant. the lungs of both hyla and bufo are complex in structure and possess one type of pneumocytes containing numerous lamellar bodies (lbs). the alveolar lining layer in the lung of hyla includes numerous lbs at different stages of transformation into a monolayer film, but the lattice is ...	1984	6421587
microsomal monooxygenase system in frog livers.	liver microsomes prepared from four species of frog, rana catesbeiana, rana nigromaculata , bufo bufo japonicus, and xenopus laevis, contained cytochrome p-450 and showed nad(p)h-dependent monooxygenase activities to several foreign chemical compounds tested. the oxidations of the chemical compounds by frog liver microsomes showed significant variations among frog species. the oxidation of 7-ethoxycoumarin was much faster than that by rat liver microsomes. the oxidation of benzo(a)pyrene was sig ...	1984	6329594
occurrence of type a and type b monoamine oxidase activities in toad egg mitochondria.	monoamine oxidase activity has been assayed radiochemically in mitochondria from bufo bufo eggs. time courses of mao activity towards pea and 5-ht indicate that when pea is used as a substrate higher specific activities are obtained. the inhibition patterns by clorgyline and deprenyl demonstrate that both type a and type b mao are present. type a activity is more sensitive than type b to the inhibitory effect of triton x-100. low concentrations of 2-mercaptoethanol cause a slight stimulation of ...	1984	6149079
metallothionein present or induced in the three species of frogs bombina orientalis, bufo bufo japonicus and hyla arborea japonica.	a low molecular weight copper (cu)- and/or zinc (zn)-binding protein was present in the livers (and kidneys) of the three species of frogs bombina orientalis, bufo bufo japonicus and hyla arborea japonica. cadmium (cd) accumulated in the livers (and kidneys) after repeated i.m. injections of cd2+ was mostly bound to the same metal-binding protein as cd, zn- or cd, zn, cu-thionein. concentrations of cd and several essential elements in the livers and kidneys of the three species of frogs were det ...	1984	6151449
mitochondrial monoamine oxidase activity during preneural developmental stages of bufo bufo.	monoamine oxidase specific activities against pea and 5-ht have been measured in mitochondria isolated from early embryos of bufo bufo. during the early development up to the neural fold stage, mao activity undergoes a continuous decrease that is more evident when pea is used as the substrate. the inhibition patterns of deprenyl and clorgyline demonstrate that, at the neural fold stage, both type a and b mao are present. both in eggs and embryos mao type a activity appears slightly more sensitiv ...	1985	2861952
effect of vasopressin on the permeability of non electrolytes across the skins of rana esculenta and bufo bufo.	maximal doses of vasopressin increase the permeability of the skins of bufo bufo and rana esculenta to urea, ethylene glycol, glycerol, erythritol, beta-alanine, leaving virtually unmodified that of mannitol and antipyrine. these results demonstrate that the response to vasopressin is quite different in amphibian skins as compared to the bladders. a careful analysis of the effects of vasopressin on non-electrolyte permeability as a function of their molecular weight demonstrates that hormone eli ...	1985	2412508
the demonstration of the spindle fiber attachments in the amphibian liver and sperm nuclei by the sera from scleroderma patients.	the isolated liver nuclei and the mature sperm nuclei from rana nigromaculata and bufo bufo asiaticus had been investigated by indirect immunofluorescence method with anti serum specific to the spindle fiber attachments (sfas) from the scleroderma patients with crest syndrome. it was found that in the isolated liver nuclei and the mature sperm nuclei of these animals there are discrete speckles which bind the antibody specific to the sfas. the maximum number of these speckles counted in a single ...	1985	3879774
the effect of acetylcholine on neurones of the amphibian nucleus isthmi.	in the bird, histochemical and biochemical data suggest that the tectal input into nucleus isthmi is of a cholinergic nature. in the present study the response of toad (bufo bufo gargarizans) isthmic neurones to acetylcholine was investigated using conventional extracellular recording techniques and ionophoresis. the results show isthmic cells to be strongly excited by acetylcholine (ach), whereas neurones in the neighbouring areas show minimal sensitivity. atropine sulphate completely blocked t ...	1985	3918767
analysis of the secretions of the subcommissural organs of several vertebrate species by use of fluorescent lectins.	the glycoprotein secretions of the subcommissural organ were analyzed with the use of nine fluorescent lectins, specific to different sugar moieties. after exposure to concanavalin a a bright fluorescence was observed in the ependymal cells of the subcommissural organs of all vertebrates studied (lampetra planeri, ameiurus nebulosus, bufo bufo, lacerta vivipara, gallus gallus, rattus norvegicus, ovis aries). the fluorescence is abolished by the competitive sugar, alpha-d-mannopyranosyl. the inte ...	1985	3919951
ultrastructural investigation on the myelinated fibres in toad medulla oblongata during metamorphosis.	the ultrastructure of myelinated fibres in the ventro-medial area of medulla oblongata of metamorphosing bufo bufo was studied. in the first stages of metamorphosis the fibres show normal distribution of the axonal organelles, while in the myelin sheaths the lamellae appear detached from one another with an irregular period and absence of the intra-period line. in the middle and final stages of metamorphosis there are myelin sheaths like those described above, but there are others with compact l ...	1985	3921606
temperature-dependent calcium sensitivity changes in skinned muscle fibres of rat and toad.	single mechanically skinned muscle fibres of different types (fast- and slow-twitch mammalian; slow and twitch amphibian) were successively activated in solutions of various ca2+ concentrations at different temperatures. an increase in temperature from 5 to 22 degrees c reversibly shifted the isometric steady-state force-pca curves towards higher ca2+ concentration for individual fibres of each of the muscle types. a further increase in temperature to 35 degrees c in mammalian fibres resulted in ...	1985	3921690
5,6-dihydroxyindole oxidation by mammalian, mushroom and amphibian tyrosinase preparations.	the oxidation of 5,6-dihydroxyindole by tyrosinases from mushroom, harding-passey melanoma, bovine eye and bufo bufo embryo has been investigated. the apparent km values for this substrate were measured and found to be of the same order of magnitude as those for l-tyrosine and l-3,4-dihydroxyphenylalanine, as reported in the literature (5 x 10(-4) m). the 5,6-dihydroxyindole oxidases of mushroom and t4 melanoma isozyme are sensitive to phenylthiourea, while, on the other hand, those from crude p ...	1985	3926006
effects of ono-3122 (an enhancer of pgh2 production) and oky-1581 (an inhibitor of txa2 production) on the vasopressin-induced water flow in the toad bladder.	the effects of 1-iodo-3-aminomethyl-5,6,7,8-tetrahydro-2-naphthol (ono-3122) which increases endogenous pgh2, and sodium (e)-2-methyl-3-[4-3-pyridylmethyl)phenyl]-2-methylpropenoate (oky-1581) which inhibits thromboxane a2 synthesis, on vasopressin-induced osmotic water flow in the bladder of the toad, bufo bufo japonicus, were examined. ono-3122 significantly inhibited the vasopressin-induced water flow at a concentration of 1 x 10(-4) m. oky-1581 inhibited the vasopressin-induced water flow at ...	1985	3927326
histochemistry of the juxtaglomerular apparatus in the toad bufo bufo. acid phosphatase activity of the epitheloid cells in the glomerular afferent arterioles.	histochemical techniques for acid phosphatase activity applied to kidney tissue of the toad bufo bufo demonstrate that a high enzyme activity is present in the dense granules of the proximal tubule cells, but also in the media cells in the wall of the glomerular afferent arterioles. the acid phosphatase activity is confined to the characteristic granules in these juxtaglomerular cells, which therefore are lysosomal in nature.	1985	3927893
epidermal tissue homeostasis. i. cell pool size, cell birth rate and cell loss by moulting in the intact toad, bufo bufo.	toad epidermis is a suitable model for studies on tissue homeostasis because cell pool size, influx into and efflux from the cell pool can be easily determined. the cell pool size was obtained by cell counting on photomicrographs, the influx (cell birth rate) was assessed by the metaphase-arrest technique, and the efflux (cell loss by moulting) assessed by counting the number of cells in the corneal layer and recording of intermoult periods. the importance of the methods for assessing these para ...	1985	3928164
the efferent vestibular neurons in the toad (bufo bufo l.): their location and morphology. a horseradish peroxidase study.	retrogradely labeled neurons are observed in the central nervous system of the toad after peripheral application of peroxidase to the anterior and posterior stumps of the viiith nerve. these efferent vestibular neurons are localized in the brainstem only ipsilaterally to the treated nerve; they are restricted within a region close to the motor nucleus of the viith nerve, outside the vestibular nuclear complex, and are predominantly localized to the borders between the gray and white matter in an ...	1985	3930000
immunoelectron microscopic localization of renin in the juxtaglomerular cells of the amphibian bufo bufo.	the ultrastructural localization of renin in the juxtaglomerular apparatus of the kidney of the toad bufo bufo has been examined using an immunogold staining method for electron microscopic immunocytochemistry and an antiserum to renin isolated from the submandibular gland of the mouse. renin immunoreactivity was confined to lamellated granules in the cytoplasm of epitheloid or juxtaglomerular cells in the glomerular afferent arterioles and also in the media cells of larger arteries. mouse kidne ...	1985	3935511
the antidromic activation of tectal neurons by electrical stimuli applied to the caudal medulla oblongata in the toad, bufo bufo l.	in order to specify the tectal projection to the bulbar/spinal regions, the antidromic responses of the physiologically identified tectal neurons as well as the gross antidromic field responses in the optic tectum to electrical stimuli applied to the caudal medulla were examined in the paralyzed common toad, bufo bufo. the antidromic field potential was recorded in the optic tectum in response to electrical stimuli applied to the ventral paramedian portion of the contralateral caudal medulla (wh ...	1985	3939244
genesis and regression of the figures of eberth and occurrence of cytokeratin aggregates in the epidermis of anuran larvae.	in tadpoles of rana temporaria, bufo bufo and xenopus laevis the development of the massive skeins of tonofilaments (cytokeratin intermediate filaments) that form the figures of eberth follows a similar sequence in all species studied. increase in the number of filaments is preceded by increase in polyribosomes and rer in the basal layer cells of the epidermis. a filamentous zone develops proximally in the cells concurrently with hemidesmosomes, which assume the typical larval bobbin form as the ...	1986	2422986
amphibian optokinetic after nystagmus: properties and comparative analysis in various species.	optokinetic nystagmus and after nystagmus were studied in six amphibian species, three urodeles and three anurans. it was demonstrated that two of the urodeles, hydromantes italicus and salamandra salamandra, display a relatively well-developed optokinetic after nystagmus, which is less pronounced in bombina variegata and nearly absent in bufo bufo, rana temporaria, and tylototriton verrucosus. these results indicate a certain degree of velocity storage in the optokinetic reflex of some amphibia ...	1986	3105809
different types of pinealocytes as revealed by immunoelectron microscopy of anti-s-antigen and antiopsin binding sites in the pineal organ of toad, frog, hedgehog and bat.	s-antigen- and opsin-immunoreactive sites were studied in the pineal organ of toad (bufo bufo), frog (rana tigrina), hedgehog (erinaceus roumanicus) and bat (myotis myotis) by light microscopic avidin-biotin-peroxidase and electron microscopic immunoglobulin-gold (immunogold), protein a-gold and avidin-biotin-ferritin techniques. the corresponding retinas served as reference tissues. a large number of photoreceptors of toad and frog pineal organ exhibited either strong or weak s-antigen immunore ...	1986	2937652
[effect of forskolin on the active transport of sodium and on the permeability of skin isolated from bufo bufo].		1986	3024675
mauthner neurons survive metamorphosis in anurans: a comparative hrp study on the cytoarchitecture of mauthner neurons in amphibians.	giant medullary neurons were revealed in adult xenopus laevis and rana esculenta following hrp injections to the spinal cord. these neurons were identified as mauthner neurons because (1) they have the same position and orientation as the larval mauthner neurons, i.e., they lie at the level of the viiith nerve root. (2) they have two large dendritic trees that for each species are similar to those of the larval mauthner neurons, (3) they are clearly distinguishable from other large reticular neu ...	1986	3081602
in vitro activation of amphibian dermal melanocytes by nicotine.	epidemiologic investigations have shown that nicotine could be a factor causing oral melanin pigmentation in man. nicotine was therefore tested on amphibian skin melanocytes. cell reactions were registered by spectrophotometry, in vitro light microscopy, photomicrography and light and electron microscopy. it was found that dermal melanocytes in the toad bufo bufo and the frog rana arvalis were activated by nicotine and that this activation was not mediated via beta-adrenergic receptors in melano ...	1986	3085206
indacrinone (mk-196)--a specific inhibitor of the voltage-dependent cl- permeability in toad skin.	the effect of indacrinone (mk-196) on cl- transport through toad (bufo bufo) skin epithelium was studied by the voltage clamping technique. at the transepithelial potential, v = 50 mv (serosal bath grounded) the unidirectional fluxes, governed by a cl- self-exchange diffusion pathway, were not affected by 1 mm racemic mk-196 in the outer bath. likewise at v = o mv, the unidirectional fluxes as well as the active (net) inward flux of cl- were unaffected by mk-196. voltage clamping the epithelium ...	1986	3088914
concentration dependence of halide fluxes and selectivity of the anion pathway in toad skin.	the isolated toad (bufo bufo) skin was mounted under voltage-clamp conditions in a chamber shown to cause no significant edge damage. the serosal side of the skin was bathed with nacl-ringer's, and the passive voltage-sensitive anion conductance studied in its fully voltage activated state, v = -80 mv (apical bath negative). the active sodium currents were eliminated by replacing external na+ with k+. with [cl-]o varying between 1.45 mm and 110 mm (gluconate substitution) and [i-]o = 3 mm, the t ...	1986	3096079
periodic changes in the rigidity of activated anuran eggs depend on germinal vesicle materials.	the eggs of xenopus laevis and bufo bufo japonicus matured in vitro by progesterone were denuded and activated by electrical shock or pricking, and their diameters were determined periodically until the postactivation time equivalent to the 8- to 16-cell stage. normally matured eggs showed a quick rounding-up and flattening immediately after activation (activation response), followed by a periodic flattening and rounding-up (postactivation response) corresponding to the intervals of early cleava ...	1986	3098597
the role of oviducal secretions in mediating gamete fusion in the toad, bufo bufo japonicus.	a fertilizing sperm of the anuran amphibians has to pass through the jelly envelopes and the vitelline envelope (ve) before making a successful fusion with the egg plasma membrane. of these the jelly envelopes, secreted by the long pars convoluta (pc) portion of the oviduct, have long been known to be indispensable for the sperm entrance in the egg. the most recent experiments employing dejellied uterine eggs of the toad, bufo bufo japonicus, revealed that the jelly plays its role in fertilizati ...	1986	3103379
glutathione peroxidases and glutathione reductase activities during bufo bufo development.	glutathione peroxidases and glutathione reductase activities are expressed from the early stage of bufo bufo development. selenium-dependent and selenium-independent glutathione peroxidase activities fluctuated independently. the activity of selenium-independent was found to be higher than that of selenium-dependent glutathione peroxidase through all stages of development. glutathione reductase activity, after a slight fall from stage 4 to stage 7, constantly increased up to stage 25.	1986	2869913
[estimation by toads of the distance to the moving objects and their true size: neuroethological and comparative aspects].	in two sets of experiments, studies have been made on the parameters by which the toad bufo bufo estimates the neighbour and remote moving objects. in absence of the structural surrounding, a dark target with a diameter 17.2 degrees (3 cm at a distance of 10 cm) and with the rate of movement 36, 72 and 145 degrees/sec evoked in toads only feeding turns; at the rates 72 and 145 degrees/sec, together with these turns, animals usually fired with their tongues to the direction of the target, reveali ...	1987	3105203
glutathione transferase activity during bufo bufo development.	high levels of glutathione transferase activity were measured during the development of the embryos of bufo bufo including unfertilized eggs. after stage 4 glutathione transferase activity gradually decreased until stage 25 when the minimum was reached. no change in the number of isozymes was noted during development according to isoelectric focusing analysis performed on the cytosolic fractions of selected stages.	1987	3107890
edge preference of retinal and tectal neurons in common toads (bufo bufo) in response to worm-like moving stripes: the question of behaviorally relevant 'position indicators'.	previous experiments have shown that during prey-catching behavior (orienting, snapping) in response to a worm-like moving stripe common toads, bufo bufo (l.) exhibit a contrast- and direction-dependent edge preference. to a black (b) stripe moving against a white (w) background (b/w), they respond (r) preferably toward the leading (l) rather the trailing (t) edge (rl greater than rt*), thus displaying 'head preference'. if the contrast-direction is reversed (w/b), the stripe's trailing edge i ...	1987	3114477
orientation behaviour of toads (bufo bufo) displaced from the breeding site.	the sensory basis and spatial range of orientation to the breeding site were studied in the toad bufo bufo, during two breeding seasons. toads were displaced passively from their breeding pond and fitted with a tracking device to record the path of migration in individuals. the directional choice and the straightness of trails after release were used to quantify the effect of experimental treatments. in both years, control (untreated) toads headed to the breeding site with the same precision at ...	1987	3119823
ultrastructural analysis and cholinesterase activity in the brain capillaries of bufo bufo and rana esculenta.	we have investigated the structure and the cholinesterase features of the brain capillaries in two adult amphibians (rana esculenta and bufo bufo). we found that brain capillaries are un-fenestrated and the endothelial cell edges are joined by tight junctions. the brain capillaries in both species are characterized by high levels of ache. this enzyme is only localized in the basal membrane, whereas we have found the reaction product neither in the endoplasmatic reticulum nor in the golgi apparat ...	1987	3121723
[cytoplasmic membranes are involved in the regulation of bufo bufo gargarizans resuming meiotic division].		1987	2834899
[effect of endogenous camp changes on the oocyte maturation of bufo bufo gargarizans].		1987	2834900
neuroglia of the optic tectum in the bufo bufo (amphibian anura), first trials.	only one predominant type of glial cell can be recognized in the bufo bufo toad's optic tectum, obtained sagitally cut in 40 microns thick sections and stained with sublimate-gold cajal's method. this basically elementary cell type is represented by ependymal gliocytes (horstmann's tanycytes) with long processes in small parallel bundles disposed radially, extending from the ventricular surface to the sub-pial surface forming terminal end-feet thickenings. these processes can lose themselves fre ...	1987	2442243
preparation and characterization of the major isotype of parvalbumin from skeletal muscle of the toad (bufo bufo japonicus).	the major isotype of parvalbumin has been isolated from the skeletal muscle of the toad, bufo bufo japonicus. unlike the skeletal muscle of every frog so far examined (rana esculenta, rana temporaria, and rana catesbeiana), which contains two major isotypes of parvalbumins, toad skeletal muscle has been shown to contain only one isotype, but the content of parvalbumin in toad skeletal muscle was similar to the sum of those of the two isotypes in skeletal muscles of frogs. this feature of toad sk ...	1987	3125161
[morphogenesis of the gonads and bidder's organs in young specimens of bufo bufo experimentally deprived of a large portion of their germ cells. i. premetamorphic stages].		1987	3128198
[morphogenesis of the gonads and bidder's organs in young specimens of bufo bufo experimentally deprived of a large portion of their germ cells. ii. premetamorphic and postmetamorphic stages].		1987	3128199
spawn predation and larval growth inhibition as mechanisms for niche separation in anurans.	we have investigated interspecific interactions between larvae of the 3 native british anurans, rana temporaria, bufo bufo and b. calamita in the field and in the laboratory. over a 3 year period, predation of b. calamita spawn by the two competitively superior species accounted for only 0.3-3.0% of the total deposited in the dune pools of the study site. however, in ponds with marked niche overlap destruction of natterjack spawn was often 100%. furthermore, growth rates of b. calamita larvae su ...	1987	28312520
seasonal changes in the migratory behaviour of the toad bufo bufo: direction and magnitude of movements.	the migratory behaviour of the toad bufo bufo was studied from february 1985 to april 1986 in the submontane region of bavaria, west germany. toads were fitted with a mechanical tracking device to record individual paths of migration. three aspects of migratory behaviour were quantified: orientation in relation to the breeding site, straightness of path, and locomotory activity. the annual activity period began with migration from the hibernation sites to the breeding pond in april. the paths we ...	1988	28312019
experimental study on the origin of pancreatic endocrine cells in the toad bufo bufo l.	ablation, transplantation and culture experiments were used to determine the respective roles of the pancreatic dorsal and ventral anlagen in the formation of the endocrine cells. three successive waves of endocrine formation occur in the pancreas of bufo bufo at three developmental stages (iii6, iv1 and iv2). each wave is derived from a different source: the first originates from the dorsal anlage, the second from the exocrine tissue of the cortex of the pancreas and the third from the pancreat ...	1988	28305560
organogenesis and differentiation of the pancreas in the toad bufo bufo l.	in bufo bufo at stage iii6 the first endocrine islets appear in the part of the pancreas corresponding to the dorsal anlage. at stage iv2, 5 days later, the pancreatic duct develops and new islets arise by budding off from the ductal epithelium. the ultrastructural study of the secretory granules morphology of endocrine cells has distinguished four different cell types: b-cells (stage iii9), a-cells (stage iv3), d-cells (stage iv3) and a fourth type not yet identified (stage iv3). by immunocytol ...	1988	28305559
riesenzellen, goblet cells, leydig cells and the large clear cells of xenopus, in the amphibian larval epidermis: fine structure and a consideration of their homology.	the origin, fate and fine structure of the epidermal riesenzellen of larvae of bufo bufo, have been described by electronmicroscopy throughout their ontogeny. riesenzellen are uncommon in the epidermis relative to the epithelial cells. in young larvae they differentiate from basal epithelial cells, which enlarge and become rounded, lucent and glandular, some at least to open at the epidermal surface. they have disappeared by the end of metamorphosis. among amphibian larval specialized cells of t ...	1988	3135114
action of forskolin on non-electrolyte permeability across the urinary bladder of bufo bufo as compared to that of various hormones.	1. forskolin, an activator of adenyl-cyclase in a receptor-independent manner, mimics the adh effect on the urea and thiourea permeabilities across the toad bladder. 2. however, differently from adh, forskolin increases the erythritol permeability across the tissue and this effect is not reproduced by two substances increasing the urea permeability (8-brcamp and isoprenaline). most probably this effect of forskolin does not involve the camp generating system.	1988	3137118
variety of structures developing after contralateral limb bud graftings on the anuran larva bufo bufo.		1988	3137460
influence of stationary and moving textured backgrounds on the response of visual neurons in toads (bufo bufo l.).	previous studies have shown that configurational prey recognition in common toads is performed by feature-analyzing functional units consisting of assemblies of connected neurons such as retinal (classes r2, r3), tectal [classes t5(1), t5(2), t5(3)], and pretectal (class th3) cells. in the present paper, effects of textured backgrounds on the response of these neurons to a configurational moving stimulus have been tested quantitatively. (1) in all investigated neurons, neither the overall activa ...	1988	3142636
metabolic costs of growth and maintenance in the toad, bufo bufo.	metabolic costs of growth and maintenance were determined from the relationship m (metabolism) = m + ng (growth), where m is the metabolic rate at the feeding level at which growth is zero. in the past, the slope n was interpreted as indicating the metabolic costs of growth, and the costs of maintenance that arise with the increase in body mass were disregarded. these costs are included in n. in female toads, bufo bufo, feeding at different rates, the uncorrected value of n was 0.44, when metabo ...	1988	3142962
nature of moulting control in amphibians: effects of cortisol implants in toads bufo bufo.	implantation of cortisol pellets in a dorsal lymph sac reduced the frequency with which toads replaced the strata cornea of the epidermis. except in a few cases, however, the replaced strata cornea were not shed as in a normal moult. the mean interval between replacements of strata cornea rose from about 9-10 days in control toads to about 18 days in intact toads bearing implants. removal of the cortisol pellets approximately 1 month after their insertion was followed by moulting on the fourth ( ...	1988	2842220
morphology of the oral disc of bufo bufo (salientia: bufonidae) tadpoles.	the fully developed oral disc of the tadpole of bufo bufo consists of dorsal and ventral labia bearing, respectively, two and three ridges bearing numerous horny denticles, a horny beak provided with jaw sheath serrations, and large lateral papillae that are borne by two cutaneous plicae. as development progresses toward metamorphosis, these structures gradually regress until they disappear. each cusped clavate labial denticle adheres, by means of a thin peduncle, to a similar labial denticle fi ...	1988	3123703
changes in monoamine oxidase activity by mitochondria isolated from late embryos of bufo bufo.	1. monoamine oxidase activity has been assayed in mitochondria isolated from post-neural embryos (stages 14-25) of bufo bufo, using 5-ht and pea as substrates. 2. mitochondria isolated from stages 19 to 25 show an increasing ability in deaminating monoamines, pea being metabolized at a higher level with respect to 5-ht. 3. at all the examined stages 5-ht is metabolized by an enzyme corresponding to mao a, while pea, from stage 19, is largely deaminated by a semicarbazide-sensitive amine oxidase ...	1988	2894273
diverse supernumerary structures develop after inverting the anteroposterior limb axis of the anuran.	contralateral limb bud graftings were performed on tadpoles of the anuran bufo bufo. the anteroposterior axis was inverted while the larvae were at stage iv or v (e.g., between 22-30 days after fertilization). eighty-four tadpoles were operated on, 10 of which were used as controls. at anterior or posterior location 104 supernumerary structures developed in toto. they were collected and whole-mount examined after being stained with alcian blue. they were further prepared for serial sectioning, m ...	1989	2466718
permeability properties of the bufo bufo bladder as affected by isoprenaline and vasopressin.	isoprenaline, a beta adrenergic agonist, strongly increases both transepithelial fluxes across the urinary bladder of bufo bufo; this effect is dose dependent, 10(-6)m being necessary for the maximal action. this effect is less selective than that of vasopressin: the ratio j urea/j thiourea is 3.8 under isoprenaline and 30.4 under vasopressin treatment. both hormones differently affect the permeability of a mainly liposoluble molecule, i.e. antipyrine: vasopressin increases antipyrine permeabili ...	1989	2483813
epidermal tissue homeostasis: apoptosis and cell emigration as mechanisms of controlled cell deletion in the epidermis of the toad, bufo bufo.	in normal, non-expanding toad epidermis more cells are produced than needed to replace cells lost by moulting. by implication, cell deletion additional to moulting must take place. this paper deals with the mechanisms by which the "surplus" of cells is deleted, taking advantage of the fact that the ratio between cell birth rate (kb) and the rate of desquamation (kd), which in normal toads is 2 to 3, can be manipulated. in toads deprived of the pars distalis of the pituitary gland it is decreased ...	1989	2501035
[experimental analysis of membrane potential changes during maturation of bufo bufo gargarizans oocytes].	the full-grown oocytes obtained from toad (bufo bufo gargarizans) submitted in hibernation state or reared at 25-30 degrees c for several months, named hibernation oocyte or high temperature oocyte, had a membrane potential of -41.51 +/- 0.77 mv and -43.83 +/- 1.39 mv in ringer's solution respectively. the hibernation oocytes underwent gvbd (germinal vesicle breakdown) and membrane depolarization at 19 +/- 1 degree c after progesterone stimulation. the membrane potential was about -20 mv at the ...	1989	2511712
[the reaction of tadpoles of the common toad (bufo bufo l.) to chemical signals from individuals of their own and other species].	in behavioral experiments, toad tadpoles-recipients chose between two parts of test aquarium with chemical signals of donor tadpoles of the same or different (rana esculenta) species. the youngest studied tadpoles (43-45 stages) preferred the part of the aquarium with chemical cues from sibs as compared to non-sibs. no reliable difference in "non-sibs: water" system was observed. in "tadpoles of the same species: tadpoles of the other species" system, recipient tadpoles chose "their" part of the ...	1989	2515677
comparative lectin-binding patterns in the epidermis and dermal glands of bufo bufo (l.) and xenopus laevis (daudin).	bouin-fixed and paraffin-embedded sections from the dorsal skin of bufo bufo and xenopus laevis were subjected to lectin histochemistry. a panel of biotinylated lectins (con-a, psa, lca, uea-i, dba, sba, sja, rca-i, bsl-i, wga, s-wga, pha-e and pha-l) and an avidin-biotin-peroxidase complex (abc) showed a species-specific compartmentalization of saccharides to certain parts of the epidermis and glandular domains. some marked histochemical differences between the two examined species adapted to f ...	1989	2517585
distribution of renal calcitonin binding sites in mammalian and nonmammalian vertebrates.	calcitonin (ct), the hypocalcemic hypophosphatemic hormone, is present in many vertebrate species. the principal target organs for ct are, in mammals, kidney and bone, and in fish, bone and gill. we have investigated the presence of renal calcitonin binding sites in a fish (salmo gairdneri), two amphibians (bufo bufo and rana esculenta), two reptiles (pseudemys scripta and gekko gecko), and two birds (gallus domesticus and cothurnix japonica). we compared their distribution to a mammal, the rat ...	1989	2555248
[the spectral characteristics of the electroencephalogram of the toad bufo bufo l. during the active and passive behavior of the animal in its circadian cycle].	using implanted electrodes, studies have been made on spectral eeg characteristics in the forebrain and midbrain of the toad during diurnal cycle. it was shown that rest constitutes more than 2/3 of 24-hour period, being presented mainly by passive wakefulness. a form of rest was revealed which may be classified as a sleep-like one.	1989	2596212
hydrins, hydroosmotic neurohypophysial peptides: osmoregulatory adaptation in amphibians through vasotocin precursor processing.	from neurointermediate pituitary glands of xenopus laevis and rana esculenta, previously unreported peptides termed hydrins, active on water permeability of frog urinary bladder and frog skin (brunn or "water-balance" effect), have been isolated and sequenced. these peptides seem to be derived from the pro-vasotocin-neurophysin precursor. hydrin 1, found in xenopus, has been identified as vasotocin c-terminally extended with the gly-lys-arg sequence; hydrin 2, found in rana, has been identified ...	1989	2787509
radial astrocytes and ependymocytes in the spinal cord of the adult toad (bufo bufo l.). an immunohistochemical and ultrastructural study.	immunohistochemical and ultrastructural techniques have been used to demonstrate glial fibrillary acidic protein (gfap) immuno-positive cells in the adult toad spinal cord. two types of gfap-immunoreactive cells were observed: ependymocytes and radial astrocytes. gfap-positive ependymocytes were scarce and contained the immunoreactive product in their processes. they showed intermediate filaments in the basal pole and in their processes when studied with the electron microscope. these immuno-pos ...	1990	2113429
[a neurophysiological analysis of the forms of wakefulness and rest in the toad bufo bufo and the frog rana ridibunda in the circadian cycle].	studies have been made on the spectral eeg parameters in the forebrain and midbrain of the toad and frog during active and passive forms of natural behaviour within a diurnal cycle. basing on evaluation of animal reactivity and on eeg analysis performed by presentation of the power of eeg signals via the frequency spectrum, it is possible to obtain a reliable identification of functional condition of amphibians. behavioural and eeg patterns of 3 forms of wakefulness and 2 forms of rest are prese ...	1990	2115707
responses of medullary neurons to moving visual stimuli in the common toad. i. characterization of medial reticular neurons by extracellular recording.	the concept of coded 'command releasing systems' proposes that visually specialized descending tectal (and pretectal) neurons converge on motor pattern generating medullary circuits and release--in goal-specific combination--specific action patterns. extracellular recordings from medullary neurons of the medial reticular formation of the awake immobilized toad in response to moving visual stimuli revealed the following main results. (i) properties of medullary neurons were distinguished by locat ...	1990	2124265
responses of medullary neurons to moving visual stimuli in the common toad. ii. an intracellular recording and cobalt-lysine labeling study.	intracellular recording and labeling of cells from the toad's (bufo bufo spinosus) medulla oblongata in response to moving visual (and tactual) stimuli yield the following results. (i) various response types characterized by extracellular recording in medullary neurons were also identified intracellularly and thus assigned to properties of medullary cell somata. (ii) focussing on monocular small-field and cyclic bursting properties, somata of such neurons were recorded most frequently in the med ...	1990	2124266
changes of a high molecular mass proteinase activity during bufo bufo development.	1. a chymotrypsin-like proteolytic activity was found both in unfertilized eggs and in embryos of bufo bufo. 2. a dramatical change of activity can be observed in the course of embryonic development. the activity rapidly increases after fertilization up to the stage 9 followed by a fall to a level close to unfertilized eggs. 3. gel chromatography analysis reveals, in all stages of development, the presence of a single peak of proteinase activity characterized by a very high molecular mass. 4. pr ...	1990	2128227
[distribution of 5-hydroxytryptamine immunostaining cells in various tissues of bufo bufo gargarizans].	the distribution of 5-hydroxytryptamine (5-ht) immunostaining cells in the digestive tracts (hibernation and nonhibernation), the brain and other various tissues of bufo bufo gargarizans was studied by peroxidase anti-peroxidase immunocytochemical method. in the brain, 5-ht immunostaining cells were localized in the raphen nuclear area of brain stem and in the ependyma cell area of the ventriclus tertius of diencephalon. these immunostaining cells were round or oval. the cells usually possess pr ...	1990	2128674
heat capacity and entropy changes of the major isotype of the toad (bufo) parvalbumin induced by calcium binding.	the possible structural changes in the major isotype of parvalbumin from the toad (bufo bufo japonicus) skeletal muscle caused by ca2+ and mg2+ binding have been analyzed by microcalorimetric titrations. parvalbumin was titrated with ca2+ in both the absence and presence of mg2+ and with mg2+ in the absence of ca2+, at ph 7.0, and at 5 degrees, 15 degrees, and 25 degrees c. the two sites in a molecule were equivalent on mg2(+)-ca2+ exchange, but distinguishable on ca2+ and mg2+ binding. the reac ...	1990	2156694
morphogenesis of the frontal organ in bufo bufo during development.	morphogenesis of the frontal organ in bufo bufo was examined under transmission electron microscope. many remarkable similarities to the frontal organ of other amphibia anura are observed. it originates from a diverticulum in the dorsal region of the neural tube. it is egg-shaped, has an eccentric lumen, and is made up of three kinds of cells: 1) photoreceptors, which protrude into the lumen; 2) supportive cells; and 3) ganglion cells, which make synaptic contact with the photoreceptors. peculia ...	1990	2350014
suspension feeding of anuran larvae at low concentrations of chlorella algae (amphibia, anura).	ingestion and filtering rates in larval xenopus laevis, bufo calamita, rana temporia and bufo bufo fed suspensions of chlorella fusca were investigated. concentrations were measured with a coulter counter. (1) for all species, filtration occurred at concentrations far below those reported by other authors for rana sylvatica feeding on chlorella pyrenoidosa. for bufo bufo, only larvae near metamorphosis showed ingestion at low particle concentrations. since buccopharyngeal ventilation continues e ...	1990	28312552
ultrastructure of neuroendocrine cells in the lungs of three anuran species.	neuroendocrine cells in the lungs of three species of anurans, bombina variegata, bufo bufo and bu. viridis, occur both as single cells and in the form of neuroepithelial bodies. neuroendocrine cells are covered by ciliated cells or pneumocytes, which separate them from the lumen of the lung. neuroepithelial bodies are dispersed in the apical part of the main septa of lungs of bo. variegata and bu. bufo or are situated on special protrusions of septa in the lungs of bu. viridis. neuroepithelial ...	1990	29865696
central and peripheral endocrine correlates of the immobility reaction in the toad bufo bufo.	the immobility reaction, which may be regarded as an innate fear response, has been observed in several animal species including amphibians. its endocrine correlates were established in the newt triturus cristatus and in the toad bufo bufo, in which the duration of immobility is influenced by sex and mating. the aim of the present study was to investigate the possibility of a relation between immobility reaction and central hormonal receptors. testosterone (t) binding capacity in the brain and p ...	1991	24896424
types of supernumerary outgrowths produced after inverting the dorsoventral limb axis of the anuranbufo bufo.	contralateral grafts were performed on the larval limb buds of the anuranbufo bufo. the dorsoventral axis of 80 buds at stages iv or v was inverted. ten tadpoles were used as controls. fifty-two supernumerary structures developed, all of them in dorsal or ventral locations on the host stump. the majority (32 out of the 44 outgrowths with more than 3 toes) were normal limbs of stump handedness. however, the following abnormal structures were also observed: 2 double-posterior, 3 mixed-symmetric, a ...	1991	28305773
comparison of the capsaicin- and amino acid-sensitivity of dorsal root c fibres in the rat and the toad.	1. the c elevation of the compound action potential (cap) was recorded with suction electrodes from dorsal roots of rats at 25 degrees c and toads (bufo bufo) at 10 degrees c. the c fibre cap had a conduction velocity of 0.5 +/- 0.07 se m per sec (n = 10) and 0.25 +/- 0.04 m per sec (n = 8) in the rat and toad nerves respectively. 2. the depressant effect of applied drugs on the amplitude of the c fibres cap was measured. nerves from both species had similar sensitivities to gaba. ec50 5.0 micro ...	1991	1685427
water and salt balance at low temperature in a cold temperate zone anuran, the toad bufo bufo.		1991	1685960