Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
pregnancy test with the male toad (bufo viridis). 194915404911
pregnancy test with the male toad, bufo viridis. 194918134933
[practical test of early pregnancy with bufo viridis]. 195114873075
[sensitivity of the male bufo viridis to chorionic gonadotrophin]. 195114840451
[effect of hydroxypropiophenone on the somatic development and metamorphosis of larvae of bufo viridis and rana agilis]. 195213008501
[cutaneous poisonous glands in bufo viridis and process of formation of secretion]. 195313033708
[the quantitative determination of chorionic gonadotropins by a biological method; definition of the biological unit based on bufo viridis from sardinia]. 195313066678
[helminths in bufo viridis laur. in the lublin province; preliminary communication]. 195813604231
isolation of bufoviridine from the skin of bufo viridis and its identification as dihydrobufothionine. 195913820720
on a new species of the genus cosmocerca diesing, 1861 from a toad, bufo viridis, in kashmir. 195913824129
[homoplastic transplants of cloacal material in anurous amphibia (bufo bufo, bufo viridis, rana esculenta)]. 196013766112
[allotriploids of the cross of female bufo vulgaris with male bufo viridis]. 196414199680
[on a fluorescent substance identified in the nerve cells of bufo viridis spinal cord. histochemical and fluorescence microscopy study]. 19645875768
histological changes in the parathyroids of bufo viridis laurenti. 19655886302
homospecific and heterospecific triploids of bufo vulgaris and bufo viridis. 19666015172
[homo- and hetero-specific androgenetic embryos of bufo vulgaris and bufo viridis]. 19675632926
free amino acids in eggs and embryos of bufo vulgaris, bufo viridis and their hybrids. 19675632813
on the problem of seasonal changes in anuran parathyroids: observations on bufo viridis in israel. 19675583869
the influence of catecholamines (epinephrine and norepinephrine) and thiamine, injected simultaneously, on the iris of bufo viridis. 19695793765
studies on the sensitivity of the iris of amphibians (hyla arborea and bufo viridis) to epinephrine and norepinephrine. 19695795817
[size and dna content of erythrocyte and spermatozoal nuclei in bufo bufo (l.) and bufo viridis (laur.)]. 19695378511
mydriatic response to phenylalanine, tyrosine, dopa, and dopamine in bufo viridis. 19705005766
role of skin and neurohypophyseal hormones in the adaptation of the toad bufo viridis to high salinities. 19715094844
hind limb regeneration in tadpoles of bufo viridis viridis laurenti, and cartilage formation from cells of non-chondrogenic origin in the thigh. 19724657701
a comparative ultrastructural study on ultimobranchial glands of some israeli anurans (bufo viridis, rana ridibunda and hyla arborea). 19724339731
studies on the adaptation of the toad bufo viridis to high salinities: oxygen consumption, plasma concentration and water content of the tissues. 19734200188
[significance of the blood protein pattern in the identification of bufo calamita laur., bufo viridis laur. and their hybrids (amphibia, anura, bufonidae)]. 19734708733
[comparative analysis of the intraspecific nuclear graft in bufo bufo l., bufo calamita laur., bufo viridis laur. (anourous amphibia)]. 19744214244
high genetic variability in an ecologically variable vertebrate, bufo viridis.allozymic variation in proteins encoded by 26 loci was analyzed electrophoretically in 517 specimens of green toads from 11 populations from israel and one population from vis island in the adriatic sea. genetic variation in this toad is the highest yet reported in any vertebrate. all three genetic parameters, mean number of alleles per locus (a), mean proportion of loci polymorphic per population (p), and mean number of heterozygous loci per individual (h), are very high (a = 1.65, range 1.38-2 ...19751203058
genetic variation as a test of natural selection.allozymic variation encoded by 26 loci was analyzed electrophoretically in 507 specimens representing 12 populations of green toads, bufo viridis, in israel and the vis adriatic island. genetic variation in bufo viridis is higher than in any vertebrate yet studied. mean heterozygosity per locus per individual (h) is 0.133 (range, 0.105 to 0.159). h is higher in central populations as compared with isolates, and varies among four major protein classes, being highest in transferases and hydrolases ...19751056019
nacl adaptation in rana ridibunda and a comparison with the euryhaline toad bufo viridis.the physiological adaptation of the frog rana ridibunda to saline environment was studied. it was found that blood was always hypertonic to the external solution, but at the highest salinity tolerated (i.e. 300 mosm) the osmotic gradient across the skin was nearly abolished. water uptake by the living frog remained unchanged, whereas sodium transport across the skin decreased markedly. neurohypophyseal hormone increased water uptake and sodium transport to levels similar to those in tap water fr ...19751214128
effect of osmolality and salinity adaptation on cellular composition and on potassium uptake, of erythrocytes from the euryhaline toad, bufo viridis. 1975240543
salt-induced changes in sodium transport across the skin of the euryhaline toad, bufo viridis.1. euryhaline toads (bufo viridis) were adapted to either distilled water, 115 or 200 mm-nacl solutions. na transport across the skin of these animals was studied in in vitro preparations. 2. salinity adaptation caused a reduction in transepithelial potential and short-circuit current across the skin, and increased its electrical resistance. 3. na influx across the skin was decreased. the reduction accounted fairly well for the measured reduction in short-circuit current. 4. short-term na uptake ...19751142300
effect of the venom sac content of the oriental hornet (vespa orientalis) on the metamorphosis of the toad tadpole (bufo viridis). 19751112359
[isolation of active gonadotropin fractions from sturgeon hypophysis and procurement of specific immune sera to them].the proteins of sturgeon hypophysis form 12 fractions when being separated by disc-electrophoresis. the maturation of the rana esculenta or bufo viridis oocytes in vitro served as a criterion of gonadotropic activity of fractions. the gonadotropic activity was shown to reside in two glycoprotein fractions with the mobilities 0.26 and 0.34. the immune serum to the former fraction is monospecific under immunodiffusion and suppresses the oocyte maturation in vitro. the immune serum to the latter fr ...1975814521
alterations in the release calls of six european anura (amphibia) after partial or total extirpation of the vocal cords.in the interior of the larynx of ranidae there are two sturdy vocal cords. the bufonidae have more delicate vocal cords, and in addition paired cushions of tissue anterior to the cords and paired folds posterior to the cords. in the three ranids rana esculenta, rana ridibunda and rana temporaria, partial or total extirpation of the vocal cords results in loss of voice or atypical release calls. in such remnants of calls as are retained, the frequency composition is little affected, whereas the i ...197624923743
histochemical studies on the tongue of anuran amphibians--ii. comparative morphochemical study of the taste buds and the lingual glands in bufo viridis laurenti and rana graeca boulenger with particular reference to the mucosaccharide histochemistry. 1977147738
changes in ionic conductances and in sensitivity to amiloride during the natural moulting cycle of toad skin (bufo viridis, l.).the resistance of the apical membranes of toad skin (bufo viridis) was measured during its natural moulting cycle using a fast flow technique. the skin behaved in all periods of the moulting cycle as a nearly perfect sodium electrode. in the presence of amiloride (10(-4)m), the total resistance of the same skin was identical with solutions which contained either sodium or potassium. the resistance of the skin with potassium was sensitive to amiloride in the period just after moulting. the resist ...1978625048
blood-group a and g specific structures in toad (bufo) spawn. comparative studies on three species (bufo bufo, bufo viridis, bufo calamita).permethylation analyses of the spawn material of three toad (bufo) species allow the conclusion that the serologically determinant group in bufo bufo spawn is identical with that found in human and hog blood-group a substances (i.e. galnac(alpha1,3) [fuc(alpha1,2)] gal -), and the serologically determinant group in bufo viridis and bufo calamita spawn is identical with that found in blood-group h substances (i.e. fuc(alpha1,2) gal -).1978569402
[cardiotropic action of green toad venom (bufo viridis laur.)]. 19806252977
the effect of dehydration on the in vivo acid-base status of the blood in the toad bufo viridis. 19806778949
acid-base status in the toad bufo viridis in vivo.the acid-base status in the toad bufo viridis was assessed on blood samples taken through a chronical cannula from unrestrained animals. blood gases and the ph were very constant in animals which were kept either under control conditions (free access to tap water) or immersed in shallow water. ph was 7.646 +/- 0.032 (mean +/- sem) in 14 control toads at 26 degrees c. pco2 was 13.1 +/- 1.2 mm hg and [hco3-] was 17.0 +/- 0.7 mmol/l at the same temperature. ph and pco2 were independent of the hemat ...19806771853
the osmotic behaviour of toad skin epithelium (bufo viridis). an electron microprobe analysis.the effect of saline adaptation on the intracellular na, k, cl, p concentrations and dry weight content of the toad skin epithelium (bufo viridis) was studied using the technique of electron microprobe analysis. the measurements were performed on isolated abdominal skins either directly after dissection or after additional incubation in ussing-type chambers. adaptations of the toads to increasing nacl concentrations for 7 days resulted in increased blood plasma osmolarity and a parallel increase ...19807191092
active transport of urea across the skin of the euryhaline toad, bufo viridis.urea is accumulated in considerable amounts (greater than 100 mm) in the blood of the euryhaline toad bufo viridis, under conditions of adaptation to high salinities. salt adaptation increases active transport of urea (inward direction) in the skin, which was measured in vitro. the active transport of urea is insensitive to adh, and was inhibited nearly 50% by 0.5 mm phloretin. this transport system is different from the facilitated diffusion of urea which has been studied extensively in the toa ...19817196032
a comparative study of auditory sensitivity in the genus bufo (amphibia).multi-unit response from the torus semicircularis were recorded to obtain neural audiograms for five different species, subspecies and races of the genus bufo:bufo b.bufo, bufo b. spinosus, two races of bufo viridis, and bufo americanus. all of the audiograms were clearly bimodal, with a low frequency peak and a high frequency peak. a less pronounced but distinguishable intermediate peak seems to be an indication of trimodality. in the low-frequency range, the audiograms of the five groups diffe ...198124925813
[the nature of urea transport across the skin of of rana esculenta].in several epithelial tissues such as toad bladder, gallbladder and human red cells, it has been established that urea movement implies a phloretin sensitive mediated transport. in the skin of the toad bufo viridis also it has been described an active transport of urea. our data, obtained on the frog skin seem to demonstrate the existence of some specific mechanism for urea transport towards the inside solution. in fact, two molecules having the some molecular diameter, such as urea and thiourea ...19826980654
urea cycle enzymes and glutamate dehydrogenase in xenopus laevis and bufo viridis adapted to high salinity.xenopus laevis was adapted stepwise to 600 m osmolar sodium chloride. after adaptation, the level of argininosuccinate lyase was raised 9-fold, carbamoylphosphate synthetase 6-fold, and ornithine carbamoyltransferase and arginase 3-fold. liver glutamate dehydrogenase was also raised 5-fold; kidney glutamate dehydrogenase was unchanged. in bufo viridis similarly adapted, there was a 5-fold increase in argininosuccinate lyase. when xenopus laevis was adapted to 600 m osmolar sucrose, there was onl ...19827097181
opiate binding sites and endogenous opioids in bufo viridis oocytes.binding sites with high affinity for [3h]naloxone, but not for [3h]morphine and [3h] (d-ala2, d-leu5) enkephalin, have been found in membranes of bufo viridis oocytes. the binding is reversible and saturable. bound [3h]naloxone is easily displaced both by unlabeled naloxone and bremazocine, much worse by morphine and skf 10,047; (d-ala2, d-leu5) enkephalin and beta-endorphin practically fail to displace [3h]naloxone. scatchard analysis is consistent with the existence of two classes of binding s ...19836320813
water balance of five amphibian species at different stages and phases, as affected by hypophysial hormones.five amphibian species were studied for the effect of hypophysial hormones on their water balance. the species were three anurans, rana ridibunda, bufo viridis and pelobates syriacus, and two urodeles salamandra salamandra and triturus vittatus. in the first four species different stages of development were studied, in the newt both the terrestrial and aquatic phases of the adult were examined. the hormones used were oxytocin (oxy), arginine vasotocin (avt) and prolactin (pl). oxytocin caused mo ...19836136381
a possible role of the kidney and urinary bladder in urea conservation of bufo viridis under high salt acclimation. 19846736867
chloride transport in toad skin (bufo viridis). the effect of salt adaptation.the steady-state cl- current across the skin of bufo viridis adapted to tap water was found to be rectified. in skins bathed with nacl ringer on both sides, a large outward current, carried by influx of cl-, was observed at a clamping voltage (v) of less than -50 mv (outside of the skin negative). for v = -50 mv the transepithelial cl- conductance calculated from isotope flux measurements was 2.5 +/- 0.3 ms cm-2, n = 10. when the skin was clamped at + 50 mv the net flux of cl- was reversed, but ...19846736866
acclimation of the euryhaline toad bufo viridis to hyperosmotic solution (nacl, urea and mannitol).bufo viridis were acclimated to hyperosmotic solutions of nacl, urea or mannitol. the toads could not be acclimated to mannitol solutions of osmotic strength higher than 300 mosmol kg-1 h2o, but could be acclimated easily to nacl and urea higher than 500 mosmol kg-1 h2o. water uptake diminished under mannitol acclimation while the apparent osmotic permeability under nacl and urea acclimation increased. urea and sodium influx across the isolated skin changed inversely upon hyperosmotic acclimatio ...19846423762
mercury-resistant plasmids in bacteria from a mercury and antimony deposit area.most bacterial cells (pseudomonas, acinetobacter) obtained from the soil at the khaidarkan mercury and antimony mine (kirghiz ussr) contain r plasmids with mercury (hgcl2) resistance determinants. the plasmids have a large molecular mass (about 100 md, though smaller ones also occur), and at least some of them are transmissive. many of the hgr bacteria also display an elevated antimony (sbcl3) resistance, though this trait was not shown to be plasmid-dependent. there are practically no hgr plasm ...19846394954
[binding sites of opiates and endogenous opioids in the oocytes of the toad bufo viridis].the binding of labelled naloxone, morphine and (d-ala2,d-leu5)enkephalin (dadl) to oocyte membranes of the toad bufo viridis was investigated. the opiate antagonist naloxone binds to the membranes much more effectively than morphine or dadl. the binding of [3h]naloxone is reversible and saturating. the bound [3h]naloxone is readily replaced by unlabelled naloxone or bremazocine (kappa-agonist), far less effectively by morphine (mu-agonist) and skf 10.047 (sigma-agonist) and is not practically re ...19846087934
[tissue basophils of the thyroid gland in developing amphibia and mammals].the number of mast cells has been established to increase sharply during the metamorphosis of bufo viridis tadpoles and during the period of postnatal ontogenesis of rats. the data obtained are under discussion to represent mast cell as a system-forming element of thyroid microregion.19846203560
[r-factors of mercury resistance in bacteria isolated in the mercury-antimony deposit region].most of bacterial cells in soil samples taken from a mine at the khaidarkan mercury-antimony deposit (kirghiz ssr) proved to contain r-plasmids with determinants of mercury resistance (hgcl2). plasmids had a high molecular mass (approximately 10(8], though some deviated substantially from this size; at least part of them were transmissible. many hgr bacteria also showed an increased resistance to antimony (sbcl3), but no relation could be found between this character and the plasmids. bacteria f ...19853158803
urea tolerance and osmoregulation in bufo viridis and rana ridibunda.1. the tolerance and adaptation to urea solutions by terrestrial green toads (bufo viridis) and semi-aquatic frogs (rana ridibunda) were studied. 2. the green toad showed tolerance to urea solution of 800 mm and the frogs showed tolerance only to about 400 mm urea solution. 3. the plasma concentrations of both species was hyperosmotic to the external medium in all the different urea solutions. 4. blood osmolality, urea, na+ and cl- concentrations of b. viridis were always higher than in r. ridib ...198514571880
osmoregulation in red blood cells of bufo viridis.the effect of hyperosmotic solution of nacl, urea and mannitol on bufo viridis red blood cells were studied. the percentage of water content in b. viridis red blood cells decreased significantly in nacl and mannitol hypertonic solutions compared to urea hypertonic solution. the urea concentration found in red blood cells in a urea hypertonic solution was significantly higher than in red blood cells acclimated to nacl and mannitol hypertonic solutions. the na+ concentration was significantly lowe ...19852864188
the role of mitochondria-rich cells in the chloride current conductance across toad skin.in early studies of salt transport across frog and toad skin, it was assumed that chloride movement is extracellular. however, later studies suggested that chloride movement is largely transcellular. chloride transport across toad skin is greatly diminished in skins of salt-acclimated toads (bufo viridis) and was correlated with the number of mitochondria-rich (m.r.) cells in the epithelium. the activated chloride conductance could be recovered upon in vitro incubation with theophylline. it was ...19852423166
occurrence of bufadienolides in the skin of bufo viridis laur. 19863791519
plasma osmolality, urine composition and tissue water content of the toad bufo viridis laur. in nature and under controlled laboratory conditions.the compositions of plasma and urine were studied in toads (bufo viridis) which were collected from three locations in israel, and compared with toads which were kept under constant laboratory conditions for nearly 2 years. plasma osmolality was rather constant (over 310 mosm kg-1 h2o) during the whole year in the active toads. urea was the most variable osmolyte in the plasma, and accounted for the higher osmolality in southern population. urine osmolality fluctuated in a circannual fashion bot ...19862879673
volume regulation in salt-acclimated toad (bufo viridis): the role of urea and the urinary bladder.body water (weight) was studied in the euryhaline toad bufo viridis during high salt (500 mosm nacl) acclimation. plasma osmolality was greatly increased upon salt acclimation mainly by urea, and was always hyperosmotic to the ambient solution. water content was regulated quite efficiently in slowly acclimated undisturbed toads. repeatedly catheterized toads behaved like osmometers when transferred to hyperosmotic solutions. total urea loss was greatly reduced in salt acclimated toads, suggestin ...19862874929
[effect of the venom of the toad bufo viridis laur. on cardiac hemodynamics in dogs].the cardiotonic effect of the secretion of the toads bufo viridis laur. skin glands and discharged bufadienolidines has been studied in the experiments on dogs under anaesthesia. it has been shown that the toad poison and bufadienolidines administered intravenously produce a marked cardiotonic and vasotonic effect, increasing the intraventricular and aortal pressure, the rate of pressure growth in the ventricles and the contraction index of the myocardium. the cardiotonic effect of poisons has a ...19863708029
[appearance of a factor stimulating oocyte maturation in the karyoplasm of the oocytes of the green toad, the clawed toad and the starred sturgeon].the karyoplasm (the contents of germinal vesicle) of the bufo viridis, xenopus laevis, and acipenser stellatus oocytes maturing under the influence of progesterone acquires the ability to induce the maturation (germinal vesicle breakdown) of the full grown oocytes, when injected into them. this ability arises in the karyoplasm earlier than in the cytoplasm and is preserved until the germinal vesicle breakdown.19863523350
the primary immune response of the green toad (bufo viridis) to challenge with crithidia fasciculata.the primary immune response of the green toad (bufo viridis) following immunization with crithidia fasciculata choanomastigotes was studied. lysins, agglutinins, and antibodies detectable by enzyme-linked immunosorbent assay (elisa) were first detected in the sera of immunized animals one week after injection. the antibody titers increased to significant levels (p less than 0.01) and maximum values were reached seven weeks post-immunization. the stimulated immunoglobulins were antigen-specific, ...19873670126
the effect of salt acclimation of the water uptake and osmotic permeability of the skin of the toad (bufo viridis, l.).1. water uptake in vivo, and water fluxes across the isolated skin were studied in salt (nacl) acclimated toads. 2. water uptake of acclimated toads maintained in the solution of acclimation, decreased with the environmental salinity. 3. the osmotic water permeability (pos) of the skin increased upon salt (nacl) acclimation, both in vivo and in vitro. 4. pos of the skin of toads acclimated to non-permeant solutes such as sucrose (230 mmol/l) or mannitol (400 nmol/l), was greatly reduced. 5. oxyt ...19873503123
an evaluation of two enzyme-substrate systems used in enzyme-linked immunosorbent assay (elisa) for the estimation of antibody levels in green toad (bufo viridis) sera. 19873595944
[rna and protein content in cells of diploid and tetraploid toads of the bufo viridis group].nucleic acids and total protein contents in hepatocytes and erythrocytes of diploid (bufo viridis, 2n = 22) and tetraploid (b. danatensis, 2n = 44) green toads were measured cytophotometrically. the rna (table 1) and protein (table 2) contents in the tetraploid cells are twice as much as that in diploid ones. according to these results tetraploidy in green toads may have a recent origin. the relation between structural and functional polyploidization in tetraploid amphibian species is discussed.19882469241
active urea transport by the skin of bufo viridis: amiloride- and phloretin-sensitive transport sites.urea is actively transported inwardly (ji) across the skin of the green toad bufo viridis. ji is markedly enhanced in toads adapted to hypertonic saline. we studied urea transport across the skin of bufo viridis under a variety of experimental conditions, including treatment with amiloride and phloretin, agents that inhibit urea permeability in the bladder of bufo marinus. amiloride (10(-4) m) significantly inhibited ji in both adapted and unadapted animals and was unaffected by removal of sodiu ...19883414802
effect of theophylline on the apical sodium and chloride permeabilities of amphibian skin.1. the effects of theophylline (1 mmol/l) on the sodium transport (short-circuit current, isc) and transepithelial conductance (gtotal) through toad (bufo viridis) and frog (rana temporaria and rana esculenta) skin were investigated. 2. in toad skin incubated with nitrate ringer solution on the apical side, theophylline induced an increase in isc similar to that in frog skin bathed with chloride ringer solution. 3. the increase in isc could be attributed to recruitment of sodium channels, withou ...19882457697
mitochondria-rich cells and carbonic anhydrase content of toad skin epithelium.the density and carbonic anhydrase (ca) content of the mitochondria-rich cells (mrcs) in the skin epithelium of the toad, bufo viridis, were studied under conditions of acclimation to various chlorinities. long-term (days to weeks) acclimation to chloride-free solutions induced a great increase in the mrc density and the area occupied by the apical portion of these cells on the surface of the epithelium. the ca content of the epithelium, and individual mr cells, showed a 5- to 10-fold reduction ...19882449967
oxygen consumption of a terrestrial toad (bufo viridis) and semi-aquatic frog (rana ridibunda).1. oxygen consumption was measured before and after dehydration at different ambient temperatures (ta) in the terrestrial toad bufo viridis and the semi-aquatic frog rana ridibunda. 2. the metabolic rates at tas between 14 and 27 degrees c were almost the same for r. ridibunda and b. viridis. 3. the metabolic rate at higher tas (between 27 and 36 degrees c) was higher in r. ridibunda than in b. viridis. this situation was found before and after dehydration. 4. a similar situation was found with ...19882896567
[the action of serotonin and its analogs on the in vitro maturation of amphibian oocytes].indolylalkylamines (5-ht, 5-chlorotryptamine, 5-ethyltryptamine) suppress or block the progesterone-induced oocyte maturation in bufo viridis and xenopus laevis and disturb cytoskeletal rearrangements associated with oocytes involved, together with the other transmitter systems, in modulation of progesterone effect.19883211454
comparison of xanthine: nad+ oxidoreductase from liver of toad bufo viridis and other vertebrates.1. xanthine oxidoreductase was isolated from toad bufo viridis (a mainly ureotelic amphibian species) and partially purified. the enzyme occurred as a stable xanthine: nad+ oxidoreductase (ec 1.1.1.204), unconvertible to the oxidase form. 2. some properties of the enzyme resembled those of xanthine oxidoreductase from an ammonotelic fish, cyprinus carpio, and the ureotelic rat, but in other aspects it was similar to this enzyme from an uricotelic snake, natrix natrix. 3. inhibition of the toad e ...19892591196
a sexual dimorphism of the harderian gland of the toad, bufo viridis.the harderian gland of the toad, bufo viridis, is an acinar gland located at the medial corner of the orbit. the columnar glandular cells show considerable variation in height depending upon their functional state. during july they are taller than in november and may, and filled with secretory seromucous granules. the glandular cells of the female toad, only, contain at their base numerous lipid droplets dispersed in a smooth endoplasmic reticulum. this is the first observation of sexual dimorph ...19892629703
the ecological significance of burrowing behaviour in the toad (bufo viridis).the burrowing behaviour of the toad bufo viridis was studied in the laboratory on soil containing 11-13% moisture. these toads usually excavate shallow, temporary burrows from which they emerge intermittently. time spent subsurface increases with rising ambient temperature in the range of 18-30° c. in these conditions, water loss is effectively reduced and a new water balance is achieved. on return to water access, after two months on soil, the toads rapidly regain only that amount of water lost ...198928312646
active urea transport in toad skin is coupled to h+ gradients.active transport of urea exists inwardly through the skin of the toad bufo viridis and is enhanced by adapting the toads to hypertonic saline solutions. in this paper, we report our studies on the energy coupling of this active transport system. we have shown previously that this system is independent of sodium transport. we thus studied the possibility of coupling to proton transport by studying the following: 1) the effect of acidifying the epithelium by means of co2 and protonophores, 2) the ...19892524167
saturable urea transport pathway across the urinary bladder of bufo viridis and salt acclimation.urea fluxes across the urinary bladder of bufo viridis were studied in vitro after modification of the mounting technique. the fluxes increased as a function of the bath urea concentration, saturating near 200 mmol/l. the apparent km was 88 mmol/l in the bladders from tapwater-acclimated toads, and 107 mmol/l in toads acclimated to 500 mosm nacl. the vmax which was 300 mumol.h-1.cm-2 at room temperature in bladders from tapwater acclimation, changed to more than 1500 mumol.h-1.cm-2 upon salt acc ...19892804458
urea transport across urinary bladder and salt acclimation in toad (bufo viridis).the fluxes of urea across the urinary bladder of the toad bufo viridis have been studied under conditions of acclimation to tap water or 500 mosm nacl solution. the [14c]urea fluxes were measured simultaneously with [3h]inulin to test for nonspecific leakage. the fluxes are quite high (ktrans = 75 x 10(-7) cm/s at 5 mmol/l urea) and are similar in either the mucosal-to-serosal or the opposite direction. "summer" rates were five to six times higher than the "winter" rates. antidiuretic hormone (a ...19902331031
chloride-related current fluctuation in amphibian skin.fluctuation in transepithelial current was analysed in skins of rana esculenta and bufo viridis. perturbation of the tissues to serosa + 40 mv or + 80 mv activated a pathway for conductive cl transport and led to the appearance of a lorentzian component in the power density spectrum. the presence of cl on the mucosal side was mandatory for the observation of lorentzians. corner frequencies, fc, ranged between 48 hz and 102 hz. the mean value was slightly larger at 40 mv than at 80 mv (88.3 +/- 4 ...19911658724
oxygen uptake of isolated toad skin epithelium: micromeasurement and effect of ionic acclimation.oxidative metabolism of isolated toad skin epithelium (bufo viridis) was investigated in vitro under open-circuit conditions using the spectrophotometric oxyhemoglobin micromethod. this highly sensitive technique has been adapted for studying several epithelia in parallel and for detecting possible regional variations of oxygen uptake in individual epithelium. changes in the proportion of mitochondria-rich cells (mrc) by ionic acclimation affected oxidative metabolism under nontransporting condi ...19912035617
the effect of aldosterone on sodium transport and membrane conductances in toad skin (bufo viridis).the effect of aldosterone (1 mumol/l for 4-6 h) on na+ transport across toad skin (bufo viridis) was studied in skins preincubated in vitro. short-circuit current (isc) was consistently and reproducibly elevated in skins from nacl(100 and 200 mmol/l)-acclimated toads, where the baseline isc was greatly reduced. the effect of aldosterone was tested in nacl and nano3 ringer's and also after oxytocin (50 mu/ml) in the latter conditions. apical membrane conductance of the principal cells increased c ...19911652121
a bactericidal protein in bombina variegata pachypus skin venom.the skin venom of the yellow bellied toad bombina variegata pachypus has an antimicrobial activity which seems to be correlated to the presence of a 6700 mol. wt polypeptide. this polypeptide was purified by electroelution from sds-urea-polyacrylamide gels and characterized for its antimicrobial activity. a bactericidal action was detected at concentrations with little or no cytolytic effect. the determination of the minimal inhibitory concentration showed that there was activity against gram po ...19912048146
anuran amphibia which are not acclimable to high salt, tolerate high plasma urea.1. the capacity of five anuran amphibians (bufo viridis, b. regularis, rana ridibunda, hyla arborea and pelobates syriacus) to acclimate to nacl and urea solutions was investigated. 2. all species could be acclimated to relatively high concentrations of urea solutions, while only bufo viridis and hyla arborea could be acclimated to 500 mosm/kg or higher nacl solutions. 3. the plasma urea concentration in b. viridis and h. arborea was elevated to levels over 140 mmol/l. 4. the sum of plasma sodiu ...19921358505
effect of forskolin on conductive anion pathways of toad skin.the effect of the diterpene, forskolin, on pathways for conductive cl- transport was analyzed using isolated skins of bufo viridis. forskolin did not stimulate the voltage-activated cl- movement from mucosa to serosa; the lorentzian component in the power density spectrum, which was present at serosa positive clamp potentials under control conditions, decreased significantly. the observation that stimulation of cytosolic adenosine 3'-5'-cyclic monophosphate (camp) by forskolin has no effect on t ...19921636675
activity of sarafotoxin/endothelin peptides in the heart and brain of lower vertebrates.the effects of sarafotoxin-b (srtx-b) and endothelin-1 (et-1) were tested in the fish tilapia (ore niloticus x o. aureus hybrids) and torpedo (torpedo ocellata), the toad (bufo viridis), the agama lizard (agama stellio) and water snake (natrix tessellata). in isolated heart preparations of the fish and agama, peptide doses of 0.05-0.5 micrograms/ml induced positive inotropic effects, reduction of the contraction rate and arrhythmia, leading to cardiac arrest. in the toad, a negative inotropic ef ...19921626325
digitalis-like compounds in the toad bufo viridis: tissue and plasma levels and significance in osmotic stress.digitalis-like compounds (dlc), constituents of animal tissues, are possible regulators of the na+, k(+)-atpase implicated in water and salt homeostasis. the distribution of dlc in the toad (bufo viridis) was determined following methanol extraction and partial purification. dlc highest levels were found in the skin but it was also detected in the plasma and many internal organs. short term (hours) exposure of the toad to hypertonic shock (1.5% nacl) induced an increase in plasma osmolarity due ...19921614277
a comparative study of melatonin production in the retina, pineal gland and harderian gland of bufo viridis and rana esculenta.1. the circadian patterns of melatonin and of its synthesizing enzyme n-acetyltransferase (nat) were investigated in the serum, retina, pineal gland and harderian gland (hg) of two amphibian species, bufo viridis and rana esculenta. 2. serum melatonin levels showed no diurnal fluctuations in bufo viridis, whereas, in rana esculenta, they exhibited a circadian rhythm, with the highest values occurring during the night. retina melatonin exhibited characteristic circadian patterns in both species, ...19937903612
promotion of muscle regeneration in the toad (bufo viridis) gastrocnemius muscle by low-energy laser irradiation.the effect of low-energy laser (he-ne) irradiation on the process of skeletal muscle regeneration after cold injury to the gastrocnemius muscle of the toad (bufo viridis) was studied using quantitative histological and morphometric methods. the injured zones in the experimental toads were subjected to five direct he-ne laser (632.8 nm wavelength) irradiations (6.0 mw for 2.3 min) every alternate day starting on the fourth day postinjury. muscles that were injured as above, and subjected to red-l ...19938430907
digitalis-like compounds in the toad bufo viridis: interactions with plasma proteins.digitalis-like compounds (dlc), normal constituents of animal tissues, are possible regulators of the na+,k(+)-atpase implicated in water and salt homeostasis. dlc are present in toad (bufo viridis) tissues. although dlc highest levels were found in toad skin, it was also detected in plasma and many internal organs. the abundant distribution and the different levels of dlc in various tissues exclude the possibility that toxicity is the only function of these compounds in the toad. the concentrat ...19937508011
differential processing of provasotocin: relative increase of hydrin 2 (vasotocinyl-gly) in amphibians able to adapt to an arid environment.hydrin 2 (vasotocinyl-gly) is an intermediate in pro-vasotocin processing found, along with vasotocin, only in the neurohypophysis of anuran amphibians. it increases cutaneous water permeability in the frog and is likely involved in neuroendocrine control of osmoregulation. the relative amounts of vasotocin and hydrin 2 stored in neurohypophysis have been measured on the one hand in amphibian species known not to adapt in dry areas, on the other hand in two species, bufo regularis (africa) and b ...19938413858
[the action of neurotransmitters and their antagonists on oocyte maturation. the action of serotonin antagonists on the in-vitro maturation of amphibian oocytes].serotonin antagonists (inmecarb hydrochloride and inmecarb methiodide) stimulate in vitro maturation of bufo viridis and xenopus laevis oocytes or potentiate the action of progesterone. in contrast to that, serotonin inhibits or blocks oocyte maturation stimulated by progesterone or serotonin antagonists. sensitivity of b. viridis oocytes to serotonin, its agonists and antagonists is subject to seasonal changes. a maximum sensitivity of intact oocytes is observed in february-march, and that of d ...19938371904
the effect of sex hormones on lipid content and mast cell number in the harderian gland of the female toad, bufo viridis.the harderian gland of the toad bufo viridis is a dimorphic gland owing to the presence of lipid droplets in the female glandular cells present only during summer months. ovariectomy causes the disappearance of sudanophilia and estrogen-treatment completely prevents this change, while testosterone-injection has little effect. estradiol-treatment also provokes a proliferation of the interstitial connective tissue concomitantly with the mast cell number increase. our results suggest that estradiol ...19947886670
enhancement of angiogenesis in regenerating gastrocnemius muscle of the toad (bufo viridis) by low-energy laser irradiation.the effect of low-energy laser (he-ne) irradiation on the process of neoformation of blood capillaries during regeneration in the toad (bufo viridis) gastrocnemius muscle was studied using histomorphometric methods. the injured zones of the experimental toads were subjected to four direct he-ne laser irradiations (632.8 nm wavelength; 6.0 mw for 2.3 min) every alternate day, commencing on the second day after injury. muscles that were injured as above and subjected to red light irradiation serve ...19947534455
effects of cyclic amp and theophylline on chloride conductance across toad skin.1. the effects of the phosphodiesterase inhibitors theophylline and isobutylmethylxanthine (ibmx) on baseline and voltage-activated cl- conductance (gcl) of toad skin were compared with those of the potent 2-chlorophenylthio analogue of camp (cpt-camp). 2. using intact and split skins of bufo viridis we confirmed that theophylline and ibmx raised the voltage-activated gcl with a pattern identical to that seen under control conditions. this effect was small or missing if gcl was already high in t ...19958583395
determination of the labyrinth in different amphibian species and its correlation with determination of the other ectoderm derivatives.the process of labyrinth determination has been studied in three urodelean and seven anuran species by means of homoplastic transplantation of ear region epidermis, defined as the piece of epidermal layer containing the material of the prospective ear vesicle (labyrinth rudiment). the ear region epidermis was grafted onto the abdominal wall of embryos of the same developmental stage. the earliest stage of operation resulting in ectopic ear vesicle formation was determined, suggesting the appeara ...199528305736
similar fine structural localization of immunoreactive glutamate in the frog pineal complex and retina.the distribution of immunoreactive glutamate was compared in the pineal complex (pineal and frontal organs) and retina of frogs (rana esculenta, r. arvalis, r. ridibunda, r. catesbeiana, bufo viridis, bombinator igneus) by postembedding immuno-electron microscopy. similar to retinal photoreceptors (rods and cones), bipolars and ganglion cells, the rod- and cone-like photoreceptors and the neurons of the pineal and frontal organs exhibited glutamate immunoreactivity. synaptic terminals of photore ...19957612360
chemopreventive effects of cabbage on 7,12-dimethylbenz(a)-anthracene-induced hepatocarcinogenesis in toads (bufo viridis).hepatocellular carcinoma was induced in the toad, bufo viridis, in 29 out of 100 cases by the administration of 0.5 mg of 7,12-dimethylbenz(a)anthracene (dmba)/toad, 3 times/week for 12 weeks. in contrast, toads treated with dmba and cabbage diet 1 or 2 ml (3 h prior to the carcinogen)/toad, every day for 12 weeks showed a lower incidence of liver tumors: 15 and 12 cases out of 100. however, cabbage diet (2 ml/toad, every day for 12 weeks) was ineffective when administered 3 h after the carcinog ...19957616322
dynamics and density of mitochondria-rich cells in toad skin epithelium.the dynamics of change in mitochondria-rich (mr) cells density in the skin epithelium of bufo viridis was studied on skin biopsies taken in vivo, throughout experimental periods lasting up to 3 months. when the bathing solution contained cl-, mr cells' density (dmrc) greatly decreased. there was one exception, when the acclimation solution was kcl, dmrc in the skin increased. the rate of decrease in dmrc depended on the mode of acclimation. when bath nacl concentration was elevated slowly in sma ...19958785520
regeneration in denervated toad (bufo viridis) gastrocnemius muscle and the promotion of the process by low energy laser irradiation.it is known that while denervated skeletal muscles have the ability to regenerate, maturation of regenerated myofibres does not take place under these conditions. denervation also causes elevation of "invasive" and satellite cells, but the role of these cells in the regeneration process after injury to the denervated muscle is still unknown. low energy lasers have recently been found to modulate and accelerate physiological processes in cells. the aim of the present study was to compare regenera ...19957879917
Refresh
firstprev
123
nextlast
Displaying items 1 - 100 of 204