effects of neurotransmitters upon the discharge of secretory product from the cutaneous glands of the red-spotted newt.the effects of sympathetic and parasympathetic agonists and antagonists on discharge of secretory product by the granular and mucous glands were examined in the red-spotted newt, notopthalmus viridescens viridescens. observations were made also on the south african clawed toad. xenopus laevis, the grass frog, rana pipiens, and the crested newt, triturus cristatus. in contrast to the granular glands of the south african clawed toad and the grass frog, which were stimulated by alpha-adrenergic age ...197721937
observations on the seasonal prevalence, pathology and transmission of dracunculus insignis (nematoda: dracunculoidea) in the raccoon (procyon lotor (l.) in ontario.lesions due to dracunculus insignis in the legs of raccoons (procyon lotor) in southern ontario occur seasonally as most larvigerous females emerge in the spring and early summer (april-june). the pathology of dracunculiasis in the raccoon is described and the transmission of the parasite in the wild is discussed with respect to seasonality and local agricultural practices. crayfish, fishes and frogs (including tadpoles) were given infective third-stage larvae of d. insignis to test their suitab ...1977144196
a survey of blood and other tissue parasites of leopard frogs rana pipiens in the united a survey of blood and other tissue parasites from 137 leopard frogs, rana pipiens complex, purchased from 13 commercial vendors in 8 states in the united states, trypanosoma pipientis was found in 2 r. p. berlandieri, toxoplasma ranae in 1 r. pipiens, isospora lieberkuehni in 1 leopard frog, haemogregarina magna in 44, lankesterella minima in 3, leptotheca ohlmacheri in 3 and microfilariae of foleyella sp. in 6. the report of i. lieberkuehni is presumably a new host record. haemogregarina tem ...1977300116
photoreceptor outer segments: accelerated membrane renewal in rods after exposure to light.the rate of rod outer segment renewal in rana pipiens tadpoles under constant light and under diurnal conditions of 12 or 2 hours light per day is significantly increased compared to that in animals in darkness. furthermore, during 24 hours in light after 6 days in darkness the rate of renewal is three to four times that in darkness. in xenopus laevis tadpoles the rate of renewal is more than five times greater during the first 8 hours of a normal diurnal cycle than during the following 16 hours ...1977300504
amphibian cells in culture. ii. isolation of drug-resistant variants and an asparagine-independent variant.with l-15 as the base medium, drug-resistant variants were isolated from two amphibian tissue culture strains: the xenopus laevis a8 diploid cell line and the icr 2a cell line of rana pipiens. four different classes of variants were obtained: (1) a8 cells resistant to chloramphenicol, an inhibitor of mitochondrial protein synthesis; (2) a8 cells resistant to ouabain, an inhibitor of the na+/k+-activated atpase of the plasma membrane;(3) icr 2a cells resistant to low (20 microgram/ml) and high (3 ...1978307557
synthesis of mitochondrial rna by full-grown and maturing oocytes of rana pipiens and xenopus laevis. 19751081057
antileptospiral activity in lower-vertebrate sera.normal serum from the painted turtle (chrysemys picta), the snapping turtle (chelydra serpentina), and the frog (rana pipiens) were found to possess bactericidal activity towards leptospira. leptospires from both the parasitic and biflexa complexes were killed by these sera at high dilutions. this pattern differs from that of mammalian serum, as generally only the biflexa complex leptospires are killed by normal mammalian serum. the activity in c. picta serum was characterized as being complemen ...19751081972
a cytoplasmic factor promoting oocyte maturation: its extraction and preliminary characterization.cytoplasm of maturing amphibian oocytes possesses a factor that induces germinal vesicle breakdown. this factor was extracted from rana pipiens eggs and assayed by microinjection in xenopus laevis oocytes. the activity of this factor is mg-dependent, ca-sensitive, and associated with heat-labile protein. centrifugation on a sucrose density gradient revealed that the factor exists in three different molecular sizes.19761083070
a serum melatonin rhythm in chickens and its abolition by pinealectomy.melatonin, a suspected hormone of the pineal organ, was extracted from chicken serum and quantified by the rana pipiens bioassay. when chickens were housed in an alternating light-dark photoperiod, serum melatonin was usually not detected during the light phase. serum melatonin rose within 1 hr after the lights were extinguished, plateaued around midnight and fell before the lights were turned on. serum melatonin was not detected at any time of day in pinealectomized chickens, suggesting that th ...19751078656
mortality in red-sided garter snakes, thamnophis sirtalis parietalis, due to larval nematode, eustrongylides sp.garter snakes, thamnophis sirtalis parietalis, that had been fed wild-caught banded killifish, fundulus diaphanus, and laboratory-bred leopard frogs, rana pipiens, were infected by larval nematode, eustrongylides sp; 7 of the 25 snakes died. signs of infection in 20 snakes included subcutaneous "lumps," violent contortions, and bloody exudate, apparently from the nares. nemotodes were collected at necropsy from beneath the skin, in the lungs, in the body cavity, and along the spinal column. nema ...1976940307
extracellular matrix synthesis in blastula and gastrula stages of normal and hybrid frog embryos. iii. characterization of galactose- and glucosamine-labelled materials.normal rana pipiens gastrulae show more incorporation of isotopically-labelled galactose and glucosamine into tca-insoluble materials than blastulae. interspecific hybrid embryos which undergo developmental arrest at the onset of gastrulation often synthesize reduced amounts of galactose- and glucosamine-labelled materials. these materials are high-molecular weight, but not collagen. after pronase digestion, labelled materials elute in the void volume of sephadex g-50. labelled materials migrate ...1977893564
parthenogenic development after chemical treatment of xenopus laevis spermatozoa.eggs of xenopus laevis were fertilized in vitro by spermatozoa pre-treated with various concentrations of aziridinyl urea (ethyleneurea) for between 30 and 120 minutes. at 2 and 4 mg/ml for 30 minutes there was a high incidence of abnormal embryos, few of which developed into tadpoles; after 6 and 8 mg/ml no tadpoles were produced. however, the highest concentration 10 mg/ml, yielded 66% of tadpoles, only 7% of which were obviously abnormal. with increasing time the same pattern of events was ob ...19751127411
changes in the structure of neuromuscular junctions caused by variations in osmotic pressure.neuromuscular junctions of the frog, rana pipiens, were examined for structural modifications produced by exposure to increased and reduced osmotic pressure (pi). preparations exposed to increased pi for varying lengths of time were fixed with either oso4-veronal with and without calcium, glutaraldehyde-phosphate, or glutaraldehyde-formaldehyde-phosphate as primary fixatives. the greatest difference between the fixatives was seen in preparations exposed to increased pi for 5 min, corresponding t ...1976818091
pineal and serum melatonin at midday and midnight following pinealectomy or castration in male rats.melatonin has been extractkd by chloroform from rat serum and quantified by the rana pipiens tadpole bioassay. like pineal melatonin, serum melatonin was high at mid-dark and low at mid-light. this finding suggests a diurnal rhythm of serum melatonin in the rat. serum samples obtained at mid-dark had melatonin levels ranging from 0.02 to 0.05 ng per ml of serum. when rats were pinealectomized, melatonin activity in the serum was abolished. thus, rat serum melatonin may originate primarily from t ...19751176905
aster formation in eggs of xenopus laevis. induction by isolated basal bodies.we have assayed various materials for their ability to induce aster formation by microinjection into unfertilized eggs of xenopus laevis. we have found that purified basal bodies from chlamydomonas reinhardtii and tetrahymena pyriformis induce the formation of asters and irregular cleavage furrows within 1 h after injection. other microtubule structures such as flagella, flagellar axonemes, cilia, and brain microtubules are completely ineffective at inducing asters or cleavage furrows in unferti ...19751236852
rate of listeria monocytogenes shedding from frogs.leopard frogs (rana pipiens) were orally inoculated with listeria monocytogenes. most listeriae were shed 3-6 days after inoculation. the evidence indicated that the listeriae did not multiply in frogs and were unable to become established in the gastrointestinal tract.1975806711
tazonomy of toxoplasma.after reviewing reports of the hosts, structure and life cycle of toxoplasma, the genus is placed in the apicomplexan family eimeriidae and the folllowing 7 species are recognized: toxoplasma gondii (nicolle & manceaux) (type species) from about 200 species of mammals and birds, with oocysts in felids; toxoplasma alencari (da costa & pereira) from the frog leptodactylus ocellatus; toxoplasma brumpti coutelen from the iguana iguana tuberculata; toxoplasma colubri tibaldi from the snakes coluber m ...1977325203
early appearance of and neuronal contribution to agrin-like molecules at embryonic frog nerve-muscle synapses formed in culture.antibodies against chicken and torpedo agrin were used for immunofluorescent staining in order to assess the spatial distribution and temporal appearance of agrin-like molecules at newly formed synaptic contacts in cultures of embryonic xenopus nerve and muscle cells. the antibodies stained xenopus neuromuscular junctions and removed ach receptor (achr)-aggregating activity from extracts of xenopus brain. immunofluorescence was observed at almost all nerve-induced achr aggregates, even at microa ...19921322981
dominant lethality in frog embryos after paternal treatment with triethylenemelamine: cytogenetics, morphology, and swimming capability.male frogs (rana pipiens) were injected intraperitoneally with triethylenemelamine (tem). the injected males were held for seven days to permit tem interaction with sperm. the tem-treated males were then spermiated with human chorionic gonadotropin (hcg) and the ova of normal females were inseminated with the sperm. direct observation was made of in vitro fertilized ova, cleavage, blastulation, and subsequent embryonic development. no differences were detected between the controls and treated an ...1979317949
frog lysozyme. v. isolation and some physical and immunochemical properties of lysozyme isozymes of the leopard frog, rana pipiens.frog lysozyme has been purified by sequential application of acid extraction, salt fractionation, cm-cellulose chromatography, heat treatment, and gel filtration. eight isozymes of purified lysozyme were found to be stable during prolonged storage. isozymes were separated by preparative polyacrylamide gel electrophoresis, ninety percent of the lytic activity of frog ovarian egg was represented by forms 7 and 8, the most highly charged isozymes. seventy-eight percent of frog liver lysozyme activi ...1977303690
the binding of labelled saxitoxin to the sodium channels in normal and denervated mammalian muscle, and in amphibian muscle.1. the binding of [3h]saxitoxin to innervated and denervated rat diaphragm muscle, and to normal frog muscle, has been measured. 2. a saturable component of saxitoxin binding, which was inhibited by tetrodotoxin, was detected in all preparations, as well as a component of non-saturable binding. the values for the maximum saturable capacity, m, and the equilibrium binding constant, k, for normal rat diaphragm muscle were: m = 24-4 wet-1, and k = 3 -8 nm. 3. denervation of rat diaphragm ...1977302332
comparison of the sequence and structure of transcription factor iiia from bufo americanus and rana pipiens.amino acid (aa) sequences of transcription factor iiia (tfiiia) from the toad, bufo americanus, and the grass frog, rana pipiens, were determined by cdna cloning and dna sequencing. the 3'-untranslated regions of the cdnas reveal that the tfiiia gene polyadenylation signal is attaaa, rather than the conventional aataaa. the b. americanus and r. pipiens proteins share about 60% aa sequence homology with each other and with xenopus laevis tfiiia. although these results indicate that tfiiia has mor ...19921398134
ultrastructure of traumatic cataractogenesis in the frog: a comparison with mouse and human lens.normal and needle-punctured lenses of rana pipiens were examined with the electron microscope in order to characterize the sequence of ultrastructural changes that follow the injury over a 5-month period. results were compared with those obtained previously in experimentally injured mouse and accidentally injured human lenses. the normal adult frog lens was found to have a morphology similar to that of mammalian lenses. as in the human, frog lens epithelial cells contained scattered microfilamen ...1977300987
frog lysozyme. iv. isozyme of lysozyme and the lucké renal adenocarcinoma.the normal kidney of the frog rana pipiens contains eight isozymes of lysozyme. three of these, however, were not present in five lucke renal adenocarcinomas. no isozymes were found to be unique to the tumor kidneys. of the five isozymes detected in tumor kidneys, only one was uniformly present, a second was present in four of five tumors, and the appearance of the other three was highly variable, although no tumor kidney contained all of them. the uniform absence of the three isozymes and the v ...1977189053
studies on the comparative pharmacology and selective toxicity of tricaine methanesulfonate: metabolism as a basis of the selective toxicity in poikilotherms.tricaine methanesulfonate, administered at a dose of 150 mg/kg i.p., produced a flaccid paralysis and loss of the righting reflex in a number of poikilothermic species including the frog. leopard frogs (rana pipiens) given 150 mg/kg i.p. regained the righting reflex at 113 +/- 28 (s.d.) minutes after injection. a similar dose administered i.p. to mice produced no apparent pharmacological response. the biological half-life (t1/2) of tricaine in frogs (r. pipiens) was about 70 minutes at temperatu ...1976185356
species differences in amphibian olfactory neuron reactivity to a monoclonal antibody.a monoclonal antibody immunostained a subpopulation of olfactory sensory neurons in cryostat sections of the olfactory mucosa of the grass frog, rana pipiens, and the bullfrog, rana catesbeiana. however, in the olfactory tissues of the african clawed frog, xenopus laevis, only mucus and mucus-secreting components were stained, and no cell-specific immunoreactivity was seen in the tiger salamander, ambystoma tigrinum. this antibody is a useful marker of olfactory neuronal subpopulations in some a ...19921617462
re-introduction and evaluation of an accurate, high capacity bioassay for melanocyte-stimulating hormone using the skin of anolis carolinensis in vitro.a simple and rapid assay for the quantitative determination of melanocyte-stimulating hormone (msh) activity, using skin fragments of the lizard anolis carolinensis in vitro, is described in detail. this assay, in which a quantal response (e.g. induction of a brownish-green colour) can be detected by visual observation, allows determination of msh activity in up to 50 samples/day by one person, using the skin of one lizard. the mean dose found to induce this colour change was 0-15 ng synthetic a ...1975170354
a link between rhodopsin and disc membrane cyclic nucleotide phosphodiesterase. action spectrum and sensitivity to illumination.frog (rana pipiens) rod outer segment disc membranes contain guanosine 3',5'-cyclic monophosphate phosphodiesterase (ec which, in the presence of atp, is stimulated 5- to 20-fold by illumination. the effectiveness of monochromatic light of different wavelengths in activating phosphodiesterase was examined. the action spectrum has a maximum of 500 nm, and the entire spectrum from 350 to 800 nm closely matches the absorption spectrum of rhodopsin, which is apparently the pigment which m ...1975167806
preparation and characterization of frog muscle myosin subfragment 1 and actin.the preparation, structural and steady-state kinetic characteristics of contractile proteins from the leg muscle of frogs rana temporaria and rana pipiens are described. actin and myosin from the two frog species are indistinguishable. the proteins have structural and steady-state kinetic properties similar to those from rabbit fast-twitch skeletal muscle. chymotrypsin digestion of frog myosin or myofibrils in the presence of edta yields subfragment 1, which is separated by chromatography into t ...1978148276
evidence for the involvement of microtubules, er, and kinesin in the cortical rotation of fertilized frog eggs.during the first cell cycle, the vegetal cortex of the fertilized frog egg is translocated over the cytoplasm. this process of cortical rotation creates regional cytoplasmic differences important in later development, and appears to involve an array of aligned microtubules that forms transiently beneath the vegetal cortex. we have investigated how these microtubules might be involved in generating movement by analyzing isolated cortices and sections of xenopus laevis and rana pipiens eggs. first ...19911714912
plasma thyroxine and triiodothyronine levels in spontaneously metamorphosing rana catesbeiana tadpoles and in adult anuran amphibia.we have developed sensitive and reliable radioimmunoassays for t4 and t3 in amphibian plasma and have used these procedures to measure plasma t4 and t3 levels in spontaneously developing rana catesbeiana tadpoles at various stages of metamorphosis. during premetamorphosis circulating levels of both t4 and t3 were below the limits of detection of the ria procedures (t4 less than 50 ng/100 ml, t3 less than 5 ng/100 ml). a gradual rise in plasma t3 and t4 became apparent during prometamorphosis, an ...1978105869
teratogenesis, toxicity, and bioconcentration in frogs exposed to dieldrin.teratogenesis, acute and chronic toxicity, growth and bioconcentration were investigated in various life stages (embryos, tadpoles, juveniles, adults) of the frogs xenopus laevis (african clawed frog), rana catesbeiana (bullfrog) and rana pipiens (leopard frog) exposed to aqueous dieldrin in static-renewal and flow-through systems in a study on the development of wildlife-based water quality criteria. r. catesbeiana was the most sensitive tadpole in acute tests; x. laevis was the most sensitive ...19911953024
viruses and renal carcinoma of rana pipiens. xv. the presence of virus-associated membrane antigen(s) on lucké tumor cells.virus-specific antigens were detected in lucké tumor cells by indirect immunofluorescence using antiserum prepared against lucké herpesvirus. intracellular fluorescence, both cytoplasmic and nuclear, was observed only in acetone:methanol-fixed tumor cells that contained herpesvirus detected by electron microscopy. the number of positive cells correlated well with the number of cells containing virus. in contrast, both virus-containing and virus-free cells exhibited membrane fluorescence when via ...197766209
high molecular weight-multicatalytic proteinases in premature and mature oocytes of rana pipiens.high molecular weight, multicatalytic proteinases (named proteasomes) have been for the first time found, on the basis of different protein patterns, in the cytoplasmic soluble fractions of both non-hormone-treated (premature) and progesterone-treated (mature) oocytes of a frog (rana pipiens). these enzymes, pooled separately as two fractions sedimenting between around 19s and the bottom (over 27s) on glycerol density gradient centrifugation, were composed of several molecular forms with apparen ...19912008178
antibodies raised against purified beta-adrenergic receptors specifically bind beta-adrenergic ligands.antibodies raised against purified beta-adrenergic receptors themselves specifically bind beta-adrenergic ligands. digitonin-solubilized frog (rana pipiens) erythrocyte beta-adrenergic receptors, purified 100- to 200-fold by adsorption to an alprenolol-agarose affinity support and specifically eluted from the affinity resin by 1-100 mm (+/-)-isoproterenol, were used to immunize six rabbits. all immune sera, in contrast to preimmune sera, bound the beta-adrenergic antagonist [(3)h]dihydroalprenol ...197936615
cytostatic factor (csf) activity in cytosols extracted from xenopus laevis eggs.cytostatic factor (csf), found in the cytoplasm of unfertilized eggs of amphibians, causes metaphase arrest when microinjected into cleaving blastomeres. although csf from rana pipiens eggs has been extracted and characterized, little is known about csf extracted from eggs of other species. we investigated the conditions required to preserve csf activity in cytosols extracted from xenopus laevis eggs and found that it was necessary to expose the eggs to co2 prior to extraction and that the extra ...19902105220
cytophysiological basis of disruptive pigmentary patterns in the leopard frog rana pipiens. ii. wild type and mutant cell-specific patterns.a new pattern index, ip, is introduced and used to compare patterns of wild type, burnsi, and kandiyohi chromatophores in the leopard frog, rana pipiens. wild type chromatophores are hyperdispersed over distances within cellular contact, and it is concluded that this hyperdispersion results from contact-mediated negative interactions. the hyperdispersion is less strong in spot cells than interspot, and extends over larger areas in burnsi than in wild type epidermis. over areas greater than chrom ...19751080207
a diurnal rhythm in melanocyte-stimulating hormone content of the rat pituitary gland and its independence from the pineal gland.resting pituitary melanocyte-stimulating hormone (msh) content was studied in adult rats kept under a controlled 14 h light-10 h dark regimen. a diurnal rhythm was found in pituitary msh levels, showing peak values at 4.00-6.00 p.m., and low values during darkness and the beginning of the light period. the normally occurring fall in pituitary msh content between 6.00 p.m. and midnight was also found in rats exposed to a prolonged photoperiod. sympathetic denervation of the pineal gland by superi ...19751079927
electrophoretic analysis of liver and testis histones of the frog rana pipiens.histones were extracted from frog livers and testes and analyzed by electrophoresis on long polyacrylamide gels and on sodium dodecyl sulfate (sds)-containing polyacrylamide gels. frog histones were found to be similar to those of calf thymus except that frog histone fraction f2a2 showed a marked dependence on the temperature at which the long gels were run, and frog histone fraction f3 could be separated from frog f2b on sds-containing gels. comparisons between frog liver and frog testis histon ...19751078823
correlated release of acetylcholine and protein from the neuromuscular junction.transmitter release at adrenergic synapses is accompanied by release of chromogranin proteins, which are contained in synaptic vesicles. to determine if a similar phenomenon occurs at the neuromuscular junction, correlated release of acetylcholine (ach) and protein was investigated using in vitro neuromuscular preparations (phrenic nerve-diaphragm muscle of the rat and mouse, sciatic nerve-sartorius muscle of rana pipiens and r. catesbeiana). nerve stimulation of curare-paralyzed preparations in ...1979220880
trh-like immunoreactivity in rat pancreas and eye, bovine and sheep pineals, and human placenta: non-identify with synthetic pyroglu-his-pro-nh2 (trh).extracts from albino rat eyes and pancreas, bovine and sheep pineals and human placenta containing trh-like immunoreactivity were chromatographed on silica-gel plates. comparison of elution profiles for trh-like immunoreactivity with that of trh revealed the presence of substances other than trh in these samples. chromatography of trh-like immunoreactivity obtained from rana pipiens skin eluted in two solvent systems produced elution profiles identical with that of synthetic pyroglu-his-pro-nh2 ...1979106925
extracellular matrix constituents and pigment cell expression in primary cell culture.three types of pigment cells were isolated and cultured from larval rana pipiens, and their attachment, maintenance, and proliferation were examined in the presence of extracellular matrix constituents (ecms) in primary cell culture. the initial profile of pigment cell types present on day 2 of culture reflects the relative attachment of the cells to the dishes. changes in the numbers of cells present after day 2 reflects the influence of factors present in the culture media on the maintenance, ...19921287625
evidence for the lack of feedback regulation of gene activity and for the absence of subunit exchange between lactate dehydrogenase tetramers in vivo.frog and rat lactate dehydrogenase (ldh, l-lactate:nad+ oxidoreductase, ec isozymes, highly purfied by affinity chromatography, were injected into newly fertilized from (rana pipiens) eggs to study the effect of the injected isozymes on the expression of the ldh genes of the developing frog embryo. from these experiments three conclusions can be drawn: (i) homologous and heterologous ldh, even when present in more than twice the normal amount of ldh, does not play any role in the switc ...19761086475
capillary permeability: atrial peptide action is independent of "protein effect".perfusion of exchange microvessels with the vasoactive hormone, atrial natriuretic peptide (ap), acutely and reversibly elevates hydraulic conductivity (lp) by mechanisms that are, as yet, unknown. this, the first of two studies to characterize ap responses when perfusate composition was altered, specifically focuses on the action of ap when perfusate albumin was lowered to change the transcapillary barrier properties for water by passive mechanisms (protein effect). perfusion of frog (rana pipi ...19902146887
capillary permeability: an albumin component attenuates active changes in lp.the mechanisms whereby atrial natriuretic peptide (ap) acutely and reversibly elevates hydraulic conductivity (lp) are not known. this is the second of two studies of the influence of perfusate albumin composition on ap alterations in capillary lp. in this study, we investigated the effect of dialysis of the perfusate albumin. a 2.2-fold increase in frog (rana pipiens) mesenteric microvessel lp occurred when 100 nm ap was added to the control perfusate containing dialyzed, crystallized bovine se ...19902146888
calcium channel effectors are potent non-competitive blockers of acetylcholine receptors.nicardipine and other calcium channel effectors (cces) were studied for their effects on nicotinic acetylcholine receptor (nachr) activity. while cces had no effect on frog (rana pipiens) skeletal muscle contractions resulting from nerve stimulation or direct stimulation of the muscle, nicotinic agonist-induced contractures were blocked. nicardipine did not affect nachr single-channel open time or amplitude, corroborating data from endplate currents (epcs); epc amplitudes and decays were unaffec ...19902172919
viral carcinogenesis in a pronephric cell line. an ultrastructural study.herpesvirus recovered from cell fractions of the spontaneous lucké renal tumor of adult rana pipiens were used to infect a cell line derived from pronephroi of the same species. viruses and virus-associated structures previously found in the primary renal tumor were observed, including nuclear inclusions of capsids with single or double membranes and capsids with nucleoids often within nuclear sacs. embedded within the clumped and marginated chromatin were 55-nm tubular elements and associated u ...19751155580
flavobacterium indologenes infection in leopard investigation of an epidemic of infectious disease in a frog (rana pipiens) colony was conducted. six of 40 frogs in a continuous (once through) water flow housing system had weight loss, swollen abdomen, corneal edema, uveitis, subcutaneous edema, petechial hemorrhage, incoordination, and respiratory distress. the frogs had lesions consistent with bacterial septicemia. a gram-negative, nonfermenting bacillus, flavobacterium indologenes (flavobacterium sp biovar iib), was isolated in pure cul ...19921293124
cytostatic factor (csf) in the eggs of xenopus laevis.cytostatic factor (csf) in unfertilized egg cytoplasm causes metaphase arrest when microinjected into zygotes. this was originally described in rana pipiens eggs in xenopus laevis, csf has also been demonstrated. but only when the calcium-chelating agent, egta, was injected into the egg cytoplasm. in the present study, however, csf was demonstrated in xenopus eggs when donor egg activation was prevented by treatment with co2 and mg2+ instead of by egta, and recipient blastomere degeneration was ...19892509228
interaction of the frog brain kainate receptor expressed in chinese hamster ovary cells with a gtp-binding protein.a protein that binds kainate with high affinity has been purified and cloned from frog brain (rana pipiens) and has approximately 35% sequence homology with mammalian non-n-methyl-d-aspartate glutamate receptors, some of which have been shown to be ligand-gated ion channels. frog brain membranes and membranes from chinese hamster ovary (cho) cells transfected with the cdna coding for the frog kainate-binding protein (cho-4 cells) bound kainate with essentially identical affinity (kd values of 1. ...19921326545
control of melanoblast differentiation in amphibia by alpha-melanocyte stimulating hormone, a serum melanization factor, and a melanization inhibiting factor.a ventrally localized melanization inhibiting factor (mif) has been suggested to play an important role in the establishment of the dorsal-ventral pigment pattern in xenopus laevis [fukuzawa and ide:dev. biol., 129:25-36, 1988]. to examine the possibility that melanoblast expression might be controlled by local putative mif and melanogenic factors, the effects of alpha-melanocyte stimulating hormone (alpha-msh), a serum melanization factor (smf) from x. laevis or rana pipiens, and mif on the "ou ...19892549532
species variation in transcription factor iiia.species variation in transcription factor iiia (tfiiia) was examined by comparing the abilities of tfiiias isolated from different xenopus and rana species to 1) bind rabbit anti-xenopus laevis tfiiia igg, 2) specifically interact with the xenopus borealis somatic 5s rna gene, and 3) promote transcription of the xenopus borealis 5s rna gene in vitro. in immunoblot assays, rana catesbeiana or rana pipiens tfiiia did not react readily with rabbit anti-xenopus laevis tfiiia igg (assayed with anti-r ...19892783776
inhibition of the transepithelial potential difference and short circuit current in the isolated frog skin by alloxan.1. electrical parameters: short circuit current (scc), transepithelial potential difference (pd) and electrical resistance (r) were measured in isolated frog skin (rana pipiens) in the presence and in the absence of alloxan. 2. alloxan decreased scc and pd in a concentration-dependent pattern, while r remained unchanged. 3. the effect on scc and pd was observed after 25 min of exposure to the drug. maximal average effect was 20% in scc and 17.5% in pd. 4. these results suggest that alloxan decre ...19921358525
mitosis-specific monoclonal antibodies block cleavage in amphibian microinjecting monoclonal antibodies that bind specifically to mitotic and meiotic cells of a variety of species, we studied the biological activity of antigens recognized by these antibodies. the antibodies recognize a family of phosphoprotein antigens that are found throughout the cytoplasm of mitotic cells and particularly at microtubule organizing centers, including centrosomes and kinetochores. their binding is dependent on phosphorylation of the polypeptides. immunoglobulins were introd ...19892787211
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 ...19892787509
adenosine receptors in frog sinus venosus: slow inhibitory potentials produced by adenine compounds and acetylcholine.1. membrane potential changes produced by adenosine and adenine nucleotides, acetylcholine, and vagus nerve stimulation were studied by intracellular recording in the sinus venosus of the frog, rana pipiens. 2. acetylcholine (ach) released from the vagus nerve terminals evoked a slow hyperpolarization lasting several seconds in the cells of the sinus. ionophoretic application of ach from a micropipette produced a response which is similar in time course and amplitude to that evoked by vagus nerv ...1979315461
inhibition of protein kinase c antagonizes in vitro tadpole tail fin regression induced by thyroxine.tail fin regression can be induced in anuran amphibians with l-thyroxine (t4). this regression can be antagonized with prolactin (prl). previous work had suggested that protein kinase c (pkc) was involved in prl action. to address this issue further, the effect of a potent and selective inhibitor of protein kinase c on in vitro tail fin regression was investigated. t4-induced regression of tail fin pieces from rana pipiens tadpoles could be antagonized by adding prl or the pkc inhibitor h-7 to t ...19921398014
several hypothalamic peptides stimulate in vitro thyrotropin secretion by pituitaries of anuran amphibians.the effects of several hypothalamic peptides on hormone secretion by pituitaries of three species of anuran amphibians were investigated using in vitro techniques. secretion of thyrotropic bioactivity (designated thyrotropin or tsh) was quantified by bioassay of the pituitary incubation medium using thyroxine (t4) production by paired thyroids from the same animals. pituitaries from adult male rana pipiens were cultured in medium alone, 10 or 100 ng/ml thyrotropin-releasing hormone (trh), 1000 n ...19882853681
[nle4, d-phe7]-alpha-msh: a superpotent melanotropin with prolonged action on vertebrate chromatophores.the in vitro and in vivo responses of integumental chromatophores to alpha-msh and a related analogue, [nle4, d-phe7] -alpha-msh, were studied in a number of vertebrate species: the teleost, lebistes reticulatus; the amphibians, rana pipiens, r. catesbeiana, xenopus laevis, bufo alvarius, and b. cognatus; the lizard, anolis carolinensis; the rattlesnake, crotalus atrox. the alpha-melanotropin analogue was a superpotent agonist in the in vitro frog (r. pipiens, r. catesbeiana) and lizard (a. caro ...19852859941
a comparative study of the membrane potential from before fertilization through early cleavage in two frogs, rana pipiens and xenopus laevis.the membrane potential of rana pipiens eggs (-55.0 mv +/- 11.2(16)) was more likely to recover from impalement and was always more negative than that of eggs of xenopus laevis (-19.3 mv +/- 4.2(68)). it was also much more negative than previously reported. essentially similar membrane resistance changes were measured in the two frog species through fertilization and cleavage. small transient depolarizations only associated with the onset of the fertilization potential in xenopus could be prevent ...19852864209
volume status influences atrial peptide-induced water conductivity changes in leopard frog mesenteric capillaries.1. three sets of north american leopard frogs (rana pipiens) were housed on damp sand (ds, n = 19), in fresh water (fw, n = 19), or with free access to both damp sand and fresh water (fa, n = 23) for a period of 5-6 days. at the end of this period pithed frogs were prepared for measurement of capillary hydraulic conductivity and samples of whole-blood, lymph and body cavity fluid were collected for measurement of haematocrit and protein content. 2. to measure hydraulic conductivity (lp), individ ...19921593450
peroxisomes in pigment epithelium and müller cells of amphibian retina possess d-amino acid oxidase as well as this paper we identify peroxisomes in müller cells and retinal pigment epithelial cells of rana pipiens and xenopus laevis by virtue of their content of cytochemically stainable catalase. these organelles have the form of an extensive, branched system of tubules in the retinal pigment epithelium and appear as discrete ovoid structures in the müller cells. in both the pigment epithelium and the müller cells a second peroxisomal enzyme, d-amino acid oxidase, can be detected in the same structur ...19882905671
cnpase activity in the vertebrate retina, retinal pigmented epithelium, and choroid.the activity of the enzyme 2',3'-cyclic nucleotide 3'-phosphohydrolase (cnpase, e.c. has been studied in the retina of three vertebrate species. activity was highest in the goldfish, followed by xenopus laevis and rana pipiens. also, high activity levels were found in goldfish retinal pigment epithelium and choroid, but not in the other two species. when added to in vitro culture systems, 2',3'-cyclic nucleotides were found to have no effect on goldfish cone retinomotor movement, but ca ...19863011952
mesencephalic fifth nucleus cell responses to thyroid hormone: one population or two?hypophysectomized rana pipiens tadpoles 3-6 months old were placed in dl-thyroxine (t4) solutions of 4 to 200 micrograms/l for 1-18 days and fixed 1 day after removal from the hormone solution. exposure times varied inversely with t4 concentration. mesencephalic fifth nucleus (m-v) cells were counted on both sides, and cell and nuclear sizes were drawn and measured for each tadpole. changes in m-v cell characteristics correlated well with t4 exposure times and concentrations, as did changes in e ...19902258718
excitatory amino acids and rod photoreceptor disc shedding: analysis using specific agonists.l-glutamate and l-aspartate stimulate photoreceptor disc shedding. in order to evaluate the possible involvement of a receptor, we examined the effects of specific excitatory amino acid agonists on rod photoreceptor disc shedding and neural retinal toxicity. using eyecups from both xenopus laevis and rana pipiens, we found that kainate, quisqualate, and n-methyl-d-aspartate (nmda) were all neurotoxic, but that kainate caused a more extensive inner retinal lesion. kainate also caused disc sheddin ...19883053226
freezing action of a metabolite of haloperidol in vivo metabolism studies led to the identification of a previously proposed metabolite of haloperidol, 4-(4'-chlorophenyl)-4-piperidinol (cppo), in the liver of a haloperidol-treated rat. however, the secondary metabolites of cppo that we have proposed were not observed in this study. neurotoxicity studies in frogs, which have been used to detect n-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (mptp) action, showed that cppo did not mimic the neurotoxicity of mptp but caused a delayed and persist ...19921599504
hormonal effects on glycogen metabolism in isolated hepatocytes of a freeze-tolerant determine whether specific hormonal responses were involved in the production of cryoprotectant (glucose) by liver of the freeze tolerant wood frog, rana sylvatica, metabolically active hepatocytes were isolated in reasonable yields (mean 20.1 +/- 1.30% sem, n = 29) by in situ liver perfusion with collagenase. freshly isolated cells from autumn-collected frogs contained large amounts of glycogen (650 mumol glucosyl units/g packed cells) and produced glucose from this endogenous reserve at a r ...19921624097
intrinsic pigment cell stimulating activity in the skin of the leopard frog, rana pipiens.consistent with the concept that specific pigment patterns of amphibians might result from the highly localized distribution of stimulators and inhibitors of pigment cell expression in the skin, the spot pattern of the leopard frog, rana pipiens, was examined through the use of the xenopus neural tube explant assay system (fukuzawa and ide, 1988). media conditioned with pieces of skin from dorsal black spotted areas promoted melanization of neural crest cells at a significantly higher level than ...19921645118
quantal release and facilitation at frog neuromuscular junctions at about 0 degrees c.1. it has been reported that at the frog neuromuscular junction at temperatures around 0 degrees c the release of transmitter quanta following nerve stimulation becomes disrupted, and the facilitation obtained after a second stimulus is no longer detectable. we thought that further investigation might give insight into the mechanism of quantal release, so we undertook experiments on rana pipiens and rana berlanieri. 2. in these species neuromuscular transmission occurs at temperatures as low as ...19911675673
thalamic and midbrain auditory projections to the preoptic area and ventral hypothalamus in the green treefrog (hyla cinerea).iontophoretic injections of horseradish peroxidase (hrp) into either the preoptic area or ventral hypothalamus of the green treefrog, (hyla cinerea), demonstrated inputs from thalamic and midbrain auditory nuclei. in a pattern similar to that seen in rana catesbeiana and rana pipiens, the central thalamic and secondary isthmal nuclei were found to provide heavy input to the ventral hypothalamus. additionally, a lighter input from the anterior thalamic nucleus was seen. in contrast, the preoptic ...19911764635
mitotic variations in the lens epithelium of the frog iv. studies with isolated anuran pituitary factors.proteins corresponding to growth hormone and prolactin have been electrophoretically separated from the pituitary gland of the frog (rana pipiens berlandieri and rana catesbeiana). these substances can independently stimulate mitosis in the lenses of animals where it had previously been inhibited by means of hypophysectomy. dna synthesis is greatly augmented six days after the start of hormone administration to intact animals. nine days are required before this occurs in hypophysectomized ones. ...19761087617
fertilization and development of frog eggs after repeated spermiation induced by human chorionic gonadotropin.sperm released into the urine of adult male frogs, rana pipiens, after intraperitoneal injection of human chorionic gonadotropin, were used to fertilize freshly ovulated eggs. repeated spermiations from the same animal were induced with repeated injections of the hormone at intervals of four to 11 days. individual frogs were induced to spermiate up to four times, with fertile sperm ensuing each time. development of zygotes produced by this method did not differ from the development of ova fertil ...19761087943
comparative molecular modeling and crystallization of p-30 protein: a novel antitumor protein of rana pipiens oocytes and early embryos.the p-30 protein (onconase) of rana pipiens oocytes and early embryos is homologous to members of the pancreatic ribonuclease superfamily and exhibits an antitumor activity in vitro and in vivo. it appears that the ribonucleolytic activity of p-30 protein may be required for its antitumor effects. a comparative molecular model of p-30 protein has been constructed based upon the known three-dimensional structure of bovine pancreatic rnase a in order to provide structural information. functionally ...19921438177
aldose reductase and p-crystallin belong to the same protein superfamily as aldehyde reductase.aldose reductase (ec has been implicated in a variety of diabetic complications. here we present the first primary sequence data for the rat lens enzyme, obtained by amino acid and cdna analysis. we have found structural similarities with another nadph-dependent oxidoreductase: human liver aldehyde reductase (ec the identity between these two enzymes is 50%. both enzymes share approx. 40-50% homology with p-crystallin, a major lens protein present only in the frog, rana pipie ...19873111886
comparative morphometric study of the vestibular system of the vertebrata: reptilia, aves, amphibia, and pisces.morphometric measurements were made from serial sections of the vestibular system in four classes of vertebrates: reptilia, aves, amphibia, and pisces. representative species of reptile studied were the lizard (gekko gecko), the common garter snake (thamnophis sp.), and the common turtle (chelonia sp.). the budgie (melopsittacus undulatas), the common pigeon (columba domestica), the yellow-bellied sapsucker (sphyrapicus varius), and the horned owl (bubo virginianus) were chosen as representative ...19863485883
cell-cycle aspects of growth and maturation of mammalian this review, recent data concerning growth and maturation of nonmammalian and mammalian female germ cells are compiled with regard to the increased understanding of somatic cells mitotic cycles, from yeast to human tissues. these data allow us to conclude that growing oocytes of nonvertebrates, lower vertebrates, and mammals resemble somatic cells in the g1 phase of the mitotic cycle in their metabolic and cell cycle behavior. transcriptional and translational activity of growing oocytes and ...19902264998
toxicity of cis-diamminedichloroplatinum (ii) (cisplatin) in the frog, rana pipiens.the toxicity of the anti-cancer drug cis-diamminedichloroplatinum (ii) (cisplatin), at 2 to 40 mg per kg, was studied in the frog, rana pipiens. the ld50 for the drug was approximately 17 mg per kg. major non-nervous system toxicity occurred in the kidney. renal failure was manifested as anasarca and increasing blood urea nitrogen (bun). histopathological changes included acute tubular necrosis and tubular dilatation, which were more severe at higher doses. interstitial fibrosis occurred after p ...19902079554
dna synthesis is unaffected but subsequent cell division is delayed in tadpole hindlimb epidermis when thyroxine is given in the rana pipiens tadpoles, thyroxine (t4) injection in the early light promotes faster hindlimb growth and development than injection early in the dark. t4 also stimulates a significant increase in cell proliferation in the basal epidermal cells of the limb. using autoradiography, we studied the timing of the t4-induced rise in the labeling and mitotic indices on 12l:12d cycles with 0.2 micrograms t4 injection early in the light or dark and on a 12l:3d:1l:8d cycle with a light pulse early in the ...19902354782
evidence for cholinergic regulation of microvessel hydraulic conductance during tissue hypoxia.cholinergic regulation of single-vessel hydraulic conductivity (lp) during normoxia and hypoxia was tested in single mesenteric vessels of pithed frogs (rana pipiens). capillaries were cannulated in situ and perfused with frog ringer's solution containing 10 mg/ml albumin and human erythrocytes while the mesentery was continuously superfused with frog ringer's solution (15 degrees c). lp was first measured under normoxic (room air equilibrated) conditions by the modified landis microocclusion me ...19902297815
cellular responses to pyrularia thionin are mediated by ca2+ influx and phospholipase a2 activation and are inhibited by thionin tyrosine iodination.pyrularia thionin, isolated from nuts of pyrularia pubera, is a strongly basic peptide of 47 amino acids. the amino acid sequence and configuration of its four disulfide bonds place this plant peptide, known to be hemolytic, cytotoxic, and neurotoxic, among the thionins. we report and compare several cellular responses mediated by pyrularia thionin: hemolysis of human erythrocytes, activation of an endogenous phospholipase a2 in swiss 3t3 cells, cytotoxicity toward hela and mouse b16 melanoma ce ...19892503825
fundulus heteroclitus gonadotropin(s). i. homologous bioassay using oocyte maturation and steroid production by isolated ovarian follicles.isolated ovarian follicles from several species were cultured to develop an in vitro bioassay system for fundulus heteroclitus gonadotropin. an extract of f. heteroclitus pituitaries, when tested in heterologous systems using follicles from rana pipiens. xenopus laevis, and carassius auratus, was ineffective in provoking either germinal vesicle breakdown or steroid production. in a homologous system using f. heteroclitus follicles, f. heteroclitus pituitary extract was capable of inducing both g ...19873497837
metamorphic rate as a function of the light/dark cycle in rana pipiens larvae.1. the rate of development of rana pipiens tadpoles in spontaneous and thyroxine (t4)-induced metamorphosis was studied on light/dark (ld) cycles in which the photophase was held constant while the scotophase was progressively extended or vice versa. 2. metamorphic rate fluctuated in both types of experiments as the ld cycle lengthened. however, the pattern of resonance differed with the length of the photophase. for example, with an 8 hr light phase, development rate slowed and then increased a ...19901975539
'neurosecretion' by a classic cholinergic innervation apparatus. a comparative study of adrenal chromaffin glands in four vertebrate species (teleosts, anurans, mammals).nerve terminals forming typical synapses with adrenal chromaffin tissues have been examined in the goldfish, frog (rana pipiens), hamster and rat. presumptive secretory inclusions present in the terminals are of two distinct types. electron-lucent synaptic vesicles 30-50 nm in diameter are densely clustered adjacent to membrane thickenings and presumably discharge their contents into the synaptic clefts. secretory granules (i.e. large dense-cored vesicles) 60-100 nm in diameter are more abundant ...19873497722
genomic potential of erythroid and leukocytic cells of rana pipiens analyzed by nuclear transfer into diplotene and maturing order to determine whether differentiated somatic cells maintain genetic totipotency, nuclear transplantations from several differentiated somatic cell types into eggs and oocytes were performed previously in rana pipiens and xenopus laevis. the formation of postneurula embryos and tadpoles under the direction of the test nuclei demonstrated their genetic multipotency. in addition, rana erythrocyte nuclei transplanted to oocytes directed more extensive tadpole development than those injected ...19921639224
tamoxifen and trifluoroperazine (stelazine) potentiate cytostatic/cytotoxic effects of p-30 protein, a novel protein possessing anti-tumor activity.p-30 protein, a novel protein isolated in our laboratory from fertilized rana pipiens eggs, has been shown to possess significant anti-proliferative and cytotoxic activity against a variety of human tumour cell lines. this protein also shows a potent anti-tumour activity in vivo in animal tumour models and is currently undergoing phase i human clinical trials in cancer patient volunteers. the present study describes the in vitro effects of the concerted action of this protein and two other agent ...19902357721
the reduction of aromatic alpha-keto acids by cytoplasmic malate dehydrogenase and lactate dehydrogenase.this study demonstrates that cytoplasmic malate dehydrogenase (mdh-s) catalyzes the reduction of aromatic alpha-keto acids in the presence of nadh, that the enzyme which has been described in the literature as aromatic alpha-keto acid reductase (kar; ec is identical to mdh-s, and that the reduction of aromatic alpha-keto acids is due predominantly to a previously unrecognized secondary activity of mdh-s and the remainder is due to the previously recognized activity of lactate dehydroge ...19872449162
classification and distribution of large intestinal bacteria in nonhibernating and hibernating leopard frogs (rana pipiens).the large intestinal flora of the leopard frog, rana pipiens, was examined to determine whether differences existed between the nonhibernating and hibernating states of the animal and to determine the relative concentrations and proportions of potential frog pathogens. hibernators had a logarithmic decrease of bacteria per milligram of intestine averaging one, and significantly greater proportions of facultative bacteria and psychrophiles relative to nonhibernators. the predominant anaerobic bac ...19883263838
possible mechanisms responsible for the reduced intestinal flora in hibernating leopard frogs (rana pipiens).mechanisms and factors that normally control the large intestinal flora were investigated to determine whether changes in these parameters could account for the decreased bacterial concentration and facultative nature of the flora found in hibernating frogs. it appeared that low temperatures and limited nutrients were the main factors responsible for the decrease in the bacterial concentration and may also have been responsible for the increase in the proportions of facultative organisms, since ...19883263839
differential sensitivity of exchange vessel hydraulic conductivity to atrial natriuretic peptide.acute plasma volume reduction by atrial natriuretic peptide (anp) may be mediated, at least in part, by increased exchange vessel water conductivity (lp). the present study tests the hypothesis that physiological levels of anp acutely and reversibly elevate single capillary lp. paired, in situ measurements of lp were obtained using the modified landis technique in individually perfused mesenteric capillaries of the frog, rana pipiens. control lp measurements ranged from 0.1 to 40 x 10(-7) cm.s-1 ...19902137988
culture of pnkt-4b cells at invasion permissive and restrictive temperatures. i. chromosomal analysis.pnkt-4b is an aneuploid cell line derived from a herpesvirus-induced renal adenocarcinoma of rana pipiens that displays restricted invasion at 21 degrees c or cooler and invasion at 23 degrees c through 28 degrees c. metaphase chromosomes obtained from subcultures (passages 297; 345-347) grown at 18 degrees c or 28 degrees c were giemsa stained or n-banded with acidic silver nitrate. cells grown at 18 degrees c displayed a modal chromosome number of 41, while 28 degrees c cultures displayed a mo ...19902328547
immunocytochemical and ultrastructural study of the frog (rana pipiens) pars distalis with special reference to folliculo-stellate cell function during in vitro superfusion.the colloidal gold immunocytochemical technique was used to determine the ultrastructural features of the glandular cells in the pituitaries of male frogs, rana pipiens, both in vivo and after superfusion in vitro. specific reactions to antisera against bullfrog gonadotropins, human prolactin, and synthetic 1-39 corticotropin allowed identification of the 3 corresponding types of glandular cells. no immunoreaction was obtained with antisera against human or ovine-growth hormone, human beta-thyro ...19892545355
viruses and renal carcinoma of rana pipiens. 3. the relationship between input multiplicity of infection and inclusion body formation in frog virus 3-infected cells. 19674166975
effect of denervation on limb growth.this study used rana pipiens tadpoles to assess the effect of complete and partial sciatic denervation on tibial bone growth and foot growth. complete sciatic denervation was performed in r. pipiens at stages xiv, xvii, and xx and they were killed at stages xvii, xx, and xxiv. partial denervation consisted of peroneal or tibial nerve sectioning at stages xvii and xx with killing at stages xx and xxiv. analysis of experimental animals and controls consisted of (a) quantitative axon counts, (b) ti ...19892783965
induction of odorant-evoked current transients in xenopus oocytes injected with mrna isolated from the olfactory mucosa of rana mrna isolated from the olfactory mucosa of the frog, rana pipiens, and from rat pup brains was microinjected into mature oocytes isolated from xenopus laevis. both populations of voltage-clamped oocytes as well as controls were non-responsive to an odorant mixture and other ligands two days later. on the 3rd day, oocytes microinjected with rat brain mrna responded to 5-hydroxytryptamine but not to an odorant mixture, while oocytes injected with rana pipiens olfactory mucosal mrna responded ...19883263588
neuropeptide y does not inhibit the release of alpha-msh from the pars intermedia of the rat adenohypophysis.neuropeptide y in concentrations from 10(-8) to 10(-6) m inhibits the release of alpha-msh from the frog (rana pipiens) pituitary in a reversible, sustained, and concentration-related manner. however, it does not inhibit the release of alpha-msh from the rat pars intermedia. thus, while neuropeptide y may play a role in the control of alpha-msh release in amphibia, it appears not to be a regulatory peptide for the mammalian pars intermedia.19882844369
viruses and renal carcinoma of rana pipiens. 13. transmission of the lucke tumor by herpesvirus-containing ascitic fluid from a tumor-bearing frog. 19724338778
phagocytic activity in the retinal pigment epithelium of the frog rana pipiens. ii. exclusion of sarcina subflava. 19744363810
species variations in the metabolism of liposoluble organochlorine compounds by hepatic microsomal monooxygenase: comparative kinetics in four vertebrate species.liposoluble organochlorine compounds were used as substrates in a kinetic study of the hepatic microsomal monooxygenases of the male rat, feral pigeon (columbia livia), frog (rana pipiens) and rainbow trout (salmo gairdnerii). substrate concentrations were taken down to environmentally realistic levels. lineweaver-burk plots gave straight lines for both aldrin (hhdn) and the dieldrin analogue hce. for both substrates activities followed the order rat greater than feral pigeon greater than trout ...19852866919
in vitro characterization of adrenergic receptors controlling skin gland secretion in two anurans rana pipiens and xenopus laevis. 19694390632
control of tectal cell number during larval development in rana pipiens.cell production and cell deaths were determined in larval rana pipiens both in control tecta and in tecta following unilateral eyeball removal in embryos and larvae. such enucleations produce significantly reduced rates of cell division in the contralateral tecta for virtually the entire larval period (confirming studies with enucleation almost exclusively performed in embryos--kollros: j. exp. zool. 123:153-187, '53, and j. comp. neurol. 205:171-178, '82). significant numbers of cell deaths in ...19883265139
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