Publications

dna replication in the amphibia.	autoradiographic techniques were used to measure rate of replication and length of the replication unit in cultured cells of scaphiopus couchi, bufo cognatus, rana clamitans, and triturus viridescens, having nuclear dna amounts in the ratio 1:4:7:39 respectively. the autoradiographic experiments were designed to show whether the larger amounts of nuclear dna are correlated with more rapid rates of synthesis and/or with longer replication units. -- the dna replication rate was 2.5 mu/minute (corr ...	1975	125187
chromosomal aberrations induced by dispersion yellow 3 in rana clamitans larvae during tail regeneration.	azo dyes have been shown to be mutagenic and toxic in a variety of organisms. the azo dye, dispersion yellow 3 is a pollutant in the river water supply of northern georgia. preliminary and definitive studies have indicated that it is mutagenic in micro-organisms and causes several malformations in chicken embryos. the present study revealed that when larvae are exposed to the dye during tail regeneration, several aberrations are seen in the squash preparations from regenerates. included are gaps ...	1979	546599
viable amphibian hybrids produced by circumventing a block to cross-fertilization(rana clamitans female x rana catesbeiana male).	eggs of rana clamitans in their own jelly coat are not fertilized by sperm of other species. when the eggs were surrounded by jelly from another species, they were fertilized by r. catesbeiana and r. septentrionalis sperm. the hybrid nature of the resulting embryos was confirmed by detection of paternal enzyme forms. the r. clamitans female times r. septentrionalis male embryos arrested by the tailbud stage. the r. clamitans female times r. catesbeiana male embryos developed into viable tadpoles ...	1975	806650
fertilization of green frog (rana clamitans) eggs in their native jelly by bullfrog (rana catesbeiana) sperm.	fertilization of r. clamitans eggs in their native jelly occurred when inseminated with high concentrations of r. catesbeiana sperm. contrary to previous evidence, the block to cross-fertilization of the r. clamitans egg is not complete. this raises the possibility that r. clamitans x r. catesbeiana hybrids may form in nature.	1975	1080794
periodicities and transient shifts in anuran (xenopus laevis, rana clamitans) oxygen consumption revealed with flow-through respirometry.	1. a custom-designed, computer-controlled, flow-through respirometry system was used to monitor oxygen consumption in aquatic anurans: xenopus laevis metamorphs and larval rana clamitans. 2. there was no evidence that animals were stressed in the flow-through respirometer; oxygen consumption rates in static vs open mode fell within the same range and animals were quiescent in the chambers. 3. diurnal periodicity was pronounced in x. laevis: both mean rates and variability of oxygen consumption w ...	1992	1348672
allozyme comparison of three trypanosoma species (kinetoplastida: trypanosomatidae) of toads and frogs by starch-gel electrophoresis.	six metabolic enzymes, glucose-6-phosphate dehydrogenase, glucosephosphate isomerase, isocitrate dehydrogenase, malate dehydrogenase, phosphoglucomutase, and purine nucleoside phosphorylase, from clonal isolates of 3 presumptive species of trypanosoma (t. fallisi, t. ranarum, and t. rotatorium) from 3 anuran hosts (bufo americanus, rana clamitans, and rana catesbeiana) were compared using starch-gel electrophoresis. although bands were shared among the different zymodemes of isolates of the same ...	1992	1556645
evidence for host allozymes present on electrophoretic gels of trematode parasites (digenea: plagiorchiiformes).	an allozyme analysis of trematode species glypthelmins californiensis, glypthelmins quieta, glypthelmins pennsylvaniensis, glypthelmins hyloreus, and haplometrana intestinalis from hosts rana aurora, rana clamitans, hyla crucifer, pseudacris triseriata, and rana pretiosa, using starch gel electrophoresis, revealed allozymes for glucose-phosphate isomerase, lactate dehydrogenase, malate dehydrogenase, and isocitrate dehydrogenase that were similar in electrophoretic mobility to host tissue contro ...	1991	1919938
helminth infracommunities of the frogs rana catesbeiana and rana clamitans from turkey marsh, michigan.	one hundred twenty-seven bullfrogs, rana catesbeiana, and 120 green frogs, rana clamitans, collected in july and august 1987 from turkey marsh, michigan, were examined for helminths. of the 16 helminth species found, falcaustra catesbeianae had the highest prevalence and mean intensity in bullfrogs. in green frogs, megalodiscus temperatus had the highest prevalence and haematoloechus parviplexus had the highest mean intensity. taxonomically, 1,030 (30.5%) trematodes and 2,348 (69.5%) nematodes o ...	1991	2040950
infectivity of cultured trypanosoma fallisi (kinetoplastida) to various anuran species and its evolutionary implications.	trypanosoma fallisi, a hemoflagellate infecting bufo americanus from ontario, was grown in vitro, and metatrypanosomes from the primary culture were inoculated into 4 uninfected test groups from 3 anuran families: bufonidae, hylidae, and ranidae. in vitro-cultured t. fallisi was found to infect b. americanus and to induce transient infections in bufo valliceps and hyla versicolor. the flagellate was not infective to rana clamitans. trypanosoma ranarum was uninfective to the bufonids and hylids t ...	1991	2040964
the occurrence of chronic hypocalcemia following parathyroidectomy in the green frog, rana clamitans.	the plasma calcium concentrations of parathyroidectomized male specimens of the green frog, rana clamitans, were monitored for 44 or 62 weeks. plasma total and ionized calcium levels of the parathyroidectomized animals decreased 31-53% within 3 days, continued to fall to approximately 50% of the preoperative levels by weeks 3-9, and remained at these low levels for the duration of the experiments. plasma sodium, ph, and hematocrit levels were unchanged. the chronic hypocalcemia resulted in tetan ...	1990	2289683
the pathogenicity, localization, and cyst structure of echinostomatid metacercariae (trematoda) infecting the kidneys of the frogs rana clamitans and rana pipiens.	light and scanning electron microscopy were used to examine the localization and pathogenicity of echinostomatid metacercariae infecting the kidneys of leopard frogs, rana pipiens, and green frogs, rana clamitans. cysts occurred predominantly in the ventrolateral renal cortex, and at least some were confined to the lumen of the bowman's capsules. each vermiform metacercarial body was enclosed by a spherical cyst wall that had a uniform thickness. the wall was composed of a homogeneous material c ...	1990	2352071
electrophoretic differentiation of two halipegus (trematoda: hemiuridae) congeners in an amphibian population.	the presence of halipegus eccentricus, which previously had been absent from a study area, was confirmed when marked genetic differences were observed within what had been thought to be a homogenous population of halipegus occidualis from the buccal region of the green frog, rana clamitans. starch gel electrophoresis was used to determine levels of genetic variation in h. occidualis and h. eccentricus. the h. occidualis population had 12% polymorphic loci and average individual heterozygosity of ...	1990	2352074
ultrastructural, biochemical and biophysical properties of an erythrocytic virus of frogs from ontario, canada.	frog erythrocytic virus (fev), one of the largest icosahedral viruses, is enveloped, measures up to 450 nm in diameter, and contains double stranded dna. the virus is found in the cytoplasm of erythrocytes of rana catesbeiana, rana septentrionalis, and rana clamitans from algonquin park, ontario (canada). acidophilic inclusions in infected erythrocytes stained with giemsa's stain correspond to viroplasms from which fev buds and forms aggregates of virus particles as seen in the electron microsco ...	1989	2810549
changes in plasma thyroxine levels during and after spontaneous metamorphosis in a natural population of the green frog, rana clamitans.	plasma thyroxine (t4) levels were measured by radioimmunoassay in a spontaneously metamorphosing population of green frog, rana clamitans, tadpoles. in accordance with species previously studied, a sharp rise in plasma t4 was seen at metamorphic climax, followed by a decline at final transformation. unlike other species studied thus far, t4 levels were also moderately high in growing tadpoles (stages x-xiii). these early elevated levels may be due to daily rhythmicity in thyroid secretion couple ...	1986	3491018
aegyptianella ranarum sp. n. (rickettsiales, anaplasmataceae): ultrastructure and prevalence in frogs from ontario.	aegyptianella ranarum sp. n. (rickettsiales, anaplasmataceae) was recorded from bullfrogs (rana catesbeiana shaw), green frogs (rana clamitans latreille) and mink frogs (rana septentrionalis baird) from five sites in southern ontario. the rickettsia occurs within membrane-bound vacuoles in the cytoplasm of erythrocytes with up to 120 organisms in mature inclusions. the pattern of replication of a. ranarum in host erythrocytes and its prevalence over a 3-yr period in frogs from algonquin park, on ...	1987	3493355
tadpole erythrocytes: luminescent properties with dark field microscopy.	to characterize and classify erythrocytes of ranid tadpoles, alcohol-fixed blood smears were studied with dark field illumination. all preclimax stage (limb bud-foot) rana castesbeiana tadpoles from ponds in massachusetts had red blood cells that were polymorphic. the majority of cells (88%) showed a bright, granular luminescence varying from white to blue-grey, whereas, cytoplasm of the other cells was smooth, black, and nonluminescent. on the other hand, tadpoles in similar stages from other s ...	1985	3877173
a block to cross-fertilization located in the egg jelly of the frog rana clamitans.		1974	4549395
behavioral reflexes in rana catesbeiana and rana clamitans with large skin grafts.		1970	4908573
comparative dna renaturation kinetics in amphibians.	amphibian haploid genome sizes vary from 9 x 10(8) to 8 x 10(10) nucleotide pairs. the rate of reassociation of dna from amphibians of different genome sizes has been employed to eliminate one of the theoretical models of chromosome structure. scaphiopus couchi, bufo marinus, and rana clamitans, whose haploid genome sizes are in the ratio 2:7:10, all contain sequences of dna represented once in the haploid genome. this indicates that their chromosomes are not composed of identical lateral strand ...	1971	5279521
studies on frog trypanosomiasis. i. a 24-hour cycle in the parasitemia level of trypanosoma rotatorium in rana clamitans from louisiana.		1968	5647105
an electron microscope study of the parathyroid gland of the frog (rana clamitans).		1965	5848842
[the color change in rana clamitans tadpoles].		1966	5989289
blood parasites of amphibians from algonquin park, ontario.	during a 5 wk period beginning may 25, 1983, 329 amphibians, which included specimens of rana catesbeiana shaw, rana clamitans latreille, rana septentrionalis baird, rana sylvatica leconte, hyla crucifer wied, bufo americanus holbrook, and plethodon cinereus green, from lake sasajewun, algonquin park, ontario, canada were examined for blood parasites. the prevalences of species of trypanosoma, haemogregarina, lankesterella, babesiasoma, and thrombocytozoons in these amphibians were determined. t ...	1984	6492319
external application of antibiotic to improve survival of adult laboratory frogs (rana pipiens).	survival data for over 500 adult frogs (393 rana pipiens, 35 rana clamitans , and 97 rana temporaria) obtained from commercial suppliers were accumulated. frogs which developed signs of red-leg disease while being kept in 0.15% saline were cured by addition of appropriate antibiotics to the saline. the appropriate antibiotic was determined by sensitivity testing of bacteria isolated from the sick frogs. when many frogs in a shipment were sick, prophylactic treatment of the entire shipment improv ...	1984	6609279
inheritance and expression of a sex-linked enzyme in the frog, rana clamitans.	the pattern of inheritance indicates that the gene for aconitase-1 is sex linked in the frog. rana clamitans, and that the male is the heterogametic sex. unlike mammals, both male and female frogs carry and express two alleles for this sex-linked gene. therefore, the sex chromosomes in these frogs and probably others behave like an autosomal pair, with one homologue carrying a male-determining element.	1983	6870771
genetic analysis of developmental arrest in an amphibian hybrid (rana catesbeiana, rana clamitans).		1981	6970150
the uptake and effects of lead in small mammals and frogs at a trap and skeet range.	this study was performed to evaluate the bioavailability and effects of lead in wildlife at a trap and skeet range. the total lead concentration in a composite soil sample (pellets removed) was 75,000 micrograms/g dry weight. elevated tissue lead concentrations and depressed alad activities in small mammals and frogs indicate that some of the lead deposited at the site is bioavailable. mean tissue lead concentrations (micrograms/g dry wt.) in white-footed mice (peromyscus leucopus) at the range ...	1996	8593083
seasonal population dynamics of halipegus occidualis and halipegus eccentricus (digenea:hemiuridae) in their amphibian host, rana clamitans.	the seasonal population dynamics of halipegus occidualis and halipegus eccentricus (hemiuridae) in their amphibian host, the green frog (rana clamitans), were examined for 3 yr (weekly, april through october). frogs were caught, marked, and examined for h. occidualis and h. eccentricus, both of which occur as immatures and adults in the buccal cavity. frogs were then released and allowed to continue natural recruitment and loss of the parasites. it was thus possible to monitor individual infrapo ...	1996	8636845
alkaline single-cell gel (comet) assay and genotoxicity monitoring using two species of tadpoles.	small bodies of water (e.g., creeks, ponds, and drainage ditches) have received very little attention in genotoxicity studies, yet these areas are important because they are often the first to be affected by industrial effluents, sewage contaminants, accidental spills, internal combustion engine emissions, landfill runoffs, and pesticide uses. to address this deficiency, we examined erythrocytes in two species of tadpoles, rana clamitans and bufo americanus, using the alkaline single-cell gel (s ...	1996	8844992
hindlimb deformities (ectromelia, ectrodactyly) in free-living anurans from agricultural habitats.	high prevalences of hindlimb deformities were recorded in wild-caught green frogs (rana clamitans), northern leopard frogs (rana pipiens), american toads, (bufo americanus), and bullfrogs (rana catesbeiana) from agricultural sites exposed to pesticide runoff in the st. lawrence river valley of québec, canada, between july and september 1992 and 1993. of 853 metamorphosing anurans examined in 14 farmland habitats, 106 (12%; range 0 to 69%) had severe degrees of ectromelia and ectrodactyly, compar ...	1997	9027696
genotoxicity monitoring of small bodies of water using two species of tadpoles and the alkaline single cell gel (comet) assay.	to monitor genotoxicity in small bodies of water (e.g., creeks, ponds, and drainage ditches) we examined tadpole erythrocytes of two species: rana clamitans and rana pipiens,using the alkaline single cell gel dna electrophoresis (scg) or "comet" assay. this approach involves detection, under alkaline conditions, of cell dna fragments which on electrophoresis migrate from the nuclear core, resulting in a "comet with tail" formation. fifty-six samples, a total of 606 tadpoles, from 18 sites in sou ...	1997	9212794
infrapopulation dynamics of halipegus occidualis and halipegus eccentricus (digenea: hemiuridae): temporal changes within individual hosts.	individual infrapopulations of halipegus occidualis and halipegus eccentricus (hemiuridae) in the buccal cavities of their amphibian host (rana clamitans) were monitored for changes over time. rates and patterns of parasite maturation, recruitment, and loss were estimated, and the probabilities of infection for definitive hosts in this system were calculated. although variable, the time required for maturation of immature worms (once in the buccal cavity) was as little as 1 wk. relatively rapid ...	1997	9406772
bridging the gap: the odonate naiad as a paratenic host for halipegus occidualis (trematoda: hemiuridae).	the temporal and spatial dynamics of the recruitment of halipegus occidualis by the green frog, rana clamitans, suggest that infections are acquired through predation on odonates, which become infected by feeding on ostracods. discrepancies in the literature regarding the life cycle of h. occidualis prompted the investigation of the status of the odonate naiad as an obligate third intermediate host. infected ostracods were examined at weekly intervals to follow the postcercarial development of t ...	1998	9488344
caged amphibian tadpoles and in situ genotoxicity monitoring of aquatic environments with the alkaline single cell gel electrophoresis (comet) assay.	in previous studies we demonstrated that indigenous amphibian tadpoles are suitable organisms for monitoring small bodies of water (e.g., creeks, ponds, and drainage ditches) using the alkaline single cell gel electrophoresis (scg) or 'comet' assay. this approach involves detection, under alkaline conditions, of cell dna fragments which on electrophoresis migrate from the nuclear core, resulting in a 'comet with tail' formation. however, although often plentiful, tadpoles are not present in all ...	1998	9651536
comparison of sensitivity to methyl methanesulphonate among tadpole developmental stages using the alkaline single-cell gel electrophoresis (comet) assay.	in a previous study, we demonstrated that tadpoles are suitable organisms for monitoring small bodies of water (e.g., creeks, ponds, and drainage ditches) for genotoxicity using the alkaline single-cell gel dna electrophoresis (scg) or "comet" assay [ralph and petras, 1997]. this approach involves detection, under alkaline conditions, of cell dna fragments which on electrophoresis migrate from the nuclear core, resulting in a "comet with tail" formation. in this initial study, most of the tadpol ...	1998	9654247
the life history and host specificity of hepatozoon clamatae (apicomplexa: adeleorina) and its-1 nucleotide sequence variation of hepatozoon species of frogs and mosquitoes from ontario.	the life cycle of an intraerythrocytic hemogregarine, hepatozoon clamatae, was studied in green frogs (rana clamitans melanota), bullfrogs (rana catesbeiana), northern leopard frogs (rana pipiens), and in the mosquito, culex territans. gametogenesis, fertilization, and sporogony occurred within cells of the malpighian tubules of laboratory-reared cx. territans that had fed on naturally infected frogs. mature oocysts containing hundreds of sporocysts were observed in mosquitoes 30 days postfeedin ...	1998	9714212
the role of habitat in structuring halipegus occidualis metapopulations in the green frog.	the transmission dynamics of the trematode halipegus occidualis in its definitive host, rana clamitans, have been examined over a 5-yr period in a north carolina pond. the breeding season of green frogs coincides with the period of worm recruitment, during which time male frogs are territorial and females show strong site fidelity. this site fidelity allows inferences to be made regarding the suitability of a particular habitat for worm transmission based on frog infection intensities within tha ...	1999	10207357
phylogenetic relationships among hepatozoon species from snakes, frogs and mosquitoes of ontario, canada, determined by its-1 nucleotide sequences and life-cycle, morphological and developmental characteristics.	the molecular biological characteristics of hepatozoon species infecting various species of snakes, frogs and mosquitoes were investigated by determining the nucleotide sequences of the first internal transcribed spacer region. a phylogenetic analysis was performed on seven isolates of hepatozoon infecting snakes, including hepatozoon sipedon and four morphologically similar but not identical forms, and two isolates of hepatozoon catesbianae infecting green frogs (rana clamitans melanota). this ...	1999	10221630
metamorphic changes in the vagal innervation to the alimentary tract in the green frog, rana clamitans (ranidae).	the alimentary tract of typical anurans shortens extensively at metamorphosis, when the microphagous tadpole transforms into a macrophagous frog. we used methylene blue vital stain and sihler stain, in conjunction with microdissection, to map the distribution of the gastric branch of the vagus nerve in green frogs (rana clamitans) before and after metamorphosis. after metamorphosis, terminal divisions of the gastric branch can be observed on the tunica musculosa extending as far as the pylorus. ...	1992	10457773
purification and characterization of antimicrobial peptides from the skin of the north american green frog rana clamitans.	ten peptides with differential growth-inhibitory activity against the gram-positive bacterium, staphylococcus aureus, the gram-negative bacterium, escherichia coli, and the yeast candida albicans were isolated from an extract of the skin of a north american frog, the green frog rana clamitans. ranatuerin-1c (smlsvlknlgkvglglvackinkqc), ranalexin-1ca (flgglmkafpalicavtkkc), ranalexin-1cb (flgglmkafpaiicavtkkc), ranatuerin-2ca (glfldtlkgaakdvagklleglkckiagc kp), and ranatuerin-2cb (glfldtlkglagkll ...	2000	10822101
ichthyophonus-like infection in wild amphibians from québec, canada.	myositis associated with infection by ichthyophonus-like organisms was diagnosed in 35 of 260 (13%) wild amphibians collected in quebec, canada, from 1959 to 1964 (n = 30), and 1992 to 1999 (n = 230). infection was diagnosed in 17 green frogs rana clamitans, 9 wood frogs r. sylvatica, 4 red-spotted newts notophthalmus viridescens, 3 bullfrogs r. catesbeiana, 1 spring peeper pseudacris crucifer, and 1 pickerel frog r. palustris. the spring peeper and one of the bullfrogs were collected in 1964 fr ...	2000	10843557
intraerythrocytic development of species of hepatozoon infecting ranid frogs: evidence for convergence of life cycle characteristics among apicomplexans.	intraerythrocytic development of the adeleorin apicomplexans hepatozoon clamatae and hepatozoon catesbianae were investigated in the bullfrog, rana catesbeiana, the green frog, rana clamitans melanota, and the northern leopard frog, rana pipiens. merozoites emerging from hepatic meronts penetrated erythrocytes and underwent 1-3 rounds of binary fission to produce 2-8 merozoites. following their release from infected erythrocytes, individual merozoites entered new cells and transformed into gamon ...	2000	10864239
chromogranin a-immunoreactive cells in the olfactory system of anuran amphibians.	chromogranin a (cga) is a member of the granin family of acidic proteins that are present in the secretory granules of many endocrine and neuroendocrine cells. the specific function(s) of these proteins is not known, but they seem to be the precursors of biologically active peptides, and they may act as helper proteins in the sorting and packaging of peptide hormones and neuropeptides. using indirect immunohistochemistry, we have found cga immunoreactivity in the primary olfactory epithelia, the ...	2000	11042007
low temperature molecular adaptation of the skeletal muscle sarco(endo)plasmic reticulum ca2+-atpase 1 (serca 1) in the wood frog (rana sylvatica).	we have compared the primary sequence and enzymatic properties of the sarcoplasmic reticulum ca(2+)-atpases from a cold-tolerant frog rana sylvatica with those of a closely related cold-intolerant frog, rana clamitans. sarcoplasmic reticulum isolated from leg muscles of both species contains a major protein ( approximately 100 kda) that reacts with a monoclonal antibody against sarco(endo)plasmic reticulum ca(2+)-atpase type 1 (serca1). the apparent molecular mass of r. sylvatica serca1 is 115 k ...	2001	11044449
limb malformations and abnormal sex hormone concentrations in frogs.	declines in amphibian populations, and amphibians with gross malformations, have prompted concern regarding the biological status of many anuran species. a survey of bullfrogs, rana catesbeiana, and green frogs, rana clamitans, conducted in central and southern new hampshire showed malformed frogs at 81% of the sites sampled (13 of 16 sites). brain gonadotropin-releasing hormone (gnrh) and the synthesis of androgens and estradiol, hormones essential to reproductive processes, were measured from ...	2000	11102301
ultrastructural design of anuran muscles used for call production in relation to the thermal environment of a species.	i examined the aerobic trunk muscles, which are used for call production, of male frogs from species that breed in different thermal environments to test the hypothesis that cold-adapted frogs should have fewer capillaries per unit mitochondrial volume in oxidative muscles than warm-adapted frogs because of reduced mitochondrial function at low temperatures. the species of interest were the cold-temperate pseudacris crucifer and the warm-tropical hyla microcephala in the family hylidae, and the ...	2001	11273806
failure of tetracycline as a biomarker in batch-marking juvenile frogs.	recent widespread amphibian declines call for better techniques to assess population dynamics. tetracycline as a biomarker in capture-recapture studies is one technique used successfully in fish, reptiles, and mammals. a two-phase experimental study was conducted to evaluate tetracycline as a biomarker in green frogs (rana clamitans) and pickerel frogs (rana palustris). in the first experimental phase tadpoles were exposed to water containing either 250 mg/l or 500 mg/l tetracycline for a period ...	2001	11310883
organochlorine insecticides, polychlorinated biphenyls, and metals in water, sediment, and green frogs from southwestern michigan.	in an attempt to explain the etiology of frog deformities and population declines, many possible causative factors have been examined, including the input of synthetic chemicals into aquatic systems, where frogs spend much of their lives, including their entire developmental stages. deformities in populations of green frogs in wetlands of southwestern michigan that are influenced by agricultural, urban, or industrial inputs were assessed in this study. of the 1445 green frogs (rana clamitans) ex ...	2001	11459136
ambient solar uv radiation causes mortality in larvae of three species of rana under controlled exposure conditions.	recent reports concerning the lethal effects of solar ultraviolet-b (uv-b) (290-320 nm) radiation on amphibians suggest that this stressor has the potential to impact some amphibian populations. in this study embryos and larvae of three anuran species, rana pipiens, rana clamitans and rana septentrionalis, were exposed to full-spectrum solar radiation and solar radiation filtered to attenuate uv-b radiation or uv-b and ultraviolet-a (uv-a) (290-380 nm) radiation to determine the effects of each ...	2001	11547564
helminth communities of green frogs rana clamitans latreille, from southwestern michigan.	a total of 239 green frogs rana clamitans, collected between june 3 and august 27, 1998 from 6 locations in southwestern michigan, was examined for helminths. of the 26 helminth taxa found, the larval cestode mesocestoides sp. had the highest mean intensity, followed by the larval trematode fibricola sp. of the helminths that mature in frogs, haematoloechus varioplexus had the highest prevalence and gorgodera amplicava had the highest mean intensity. frogs from 118th pond had the highest species ...	2001	11695416
species specificity of o-linked carbohydrate chains of the oviducal mucins in amphibians: structural analysis of neutral oligosaccharide alditols released by reductive beta-elimination from the egg-jelly coats of rana clamitans.	the extracellular matrix (the so-called jelly coat) surrounding amphibian eggs mainly comprises highly o-glycosylated proteins. these oviducal mucins have an important role in the fertilization process, and their carbohydrate chains are remarkably species-specific. alkaline reductive treatment of the jelly-coat material of the frog rana clamitans led to the release of oligosaccharide alditols. the neutral oligosaccharide alditols were fractionated and purified by successive chromatographic techn ...	2002	11964146
density-dependent growth and metamorphosis in the larval bronze frog rana temporalis is influenced by genetic relatedness of the cohort.	effects of density and kinship on growth and metamorphosis in tadpoles of rana temporalis were studied in a 2 4 factorial experiment. fifteen egg masses were collected from streams in the western ghat region of south india. the tadpoles were raised as siblings or in groups of non-siblings at increasing density levels, viz. 15, 30, 60 and 120/5 l water. with an increase in density level from 15 to 120 tadpoles/5 l water, duration of the larval stage increased and fewer individuals metamorphosed i ...	2003	12799495
the relation of nucleic acid and protein to pancreatic secretion in the rana clamitans tadpole.		1955	13241506
fine structure of the larval anuran epidermis, with special reference to the figures of eberth.	small pieces of skin from 8 cm long rana clamitans larvae were fixed in oso(4), washed, dehydrated, and embedded in a methacrylate mixture. ultrathin sections were cut on a porter-blum ultramicrotome and were examined in an rca electron microscope, type emu 2d. the sections showed that aggregates of fibrous material in the cells of the inner layer of epidermal cells are identical in disposition and size with the classical figures of eberth. it is conclusively shown that these figures do not aris ...	1961	13692395
the absorption of amino acids by the isolated intestine of the green frog. rana clamitans.		1961	13702921
the effect of chymotrypsin on the development of rana clamitans.		1960	13796660
regeneration and repair of the intestine in rana clamitans larvae.		1959	13854145
some factors modifying the absorption of amino acids by the isolated intestine of the green frog, rana clamitans.		1961	13896194
metamorphic changes in the blood sugar and the pancreatic islets of the frog, rana clamitans.		1964	14131456
effect of ph and release on two life stages of four anuran amphibians.	using three native canadian and one exotic anuran species, the interactive toxicity of ph and the forestry used-herbicide release (triclopyr [3,5,6-trichloro-2-pyridl-oxyacetic acid]) was assessed. embryonic and larval (gosner 25) stages of rana pipiens, rana clamitans, bufo americanus, and xenopus laevis were exposed to treatments for at least 96 h in a static-renewal system using a central composite rotatable design. mortality and the prevalence of malformations were modeled using generalized ...	2003	14587907
effects of carbaryl on green frog (rana clamitans) tadpoles: timing of exposure versus multiple exposures.	the majority of studies on pesticide impacts have evaluated the effects of single exposures. however, multiple exposures to a pesticide may be more prevalent. the objective of our study was to determine how multiple exposures versus single exposure at different times during development affected survival to metamorphosis, tadpole survival, tadpole mass, and tadpole developmental stage of green frog (rana clamitans) tadpoles reared at low and high density in outdoor cattle tank ponds. tadpoles wer ...	2003	14587910
species-specific responses of developing anurans to coal combustion wastes.	field surveys and field experiments have previously documented adverse effects of solid byproducts from coal incineration (coal combustion wastes (ccw)) on larval amphibians inhabiting aquatic habitats. however, a definitive link between ccw-exposure and developmental abnormalities has not been established because no studies have addressed the direct effects of prolonged exposure to ccw on larval amphibian development under controlled laboratory conditions. in the laboratory we exposed green fro ...	2004	15036872
comparative effects of ph and vision herbicide on two life stages of four anuran amphibian species.	vision, a glyphosate-based herbicide containing a 15% (weight:weight) polyethoxylated tallow amine surfactant blend, and the concurrent factor of ph were tested to determine their interactive effects on early life-stage anurans. ninety-six-hour laboratory static renewal studies, using the embryonic and larval life stages (gosner 25) of rana clamitans, r. pipiens, bufo americanus, and xenopus laevis, were performed under a central composite rotatable design. mortality and the prevalence of malfor ...	2004	15095875
effects of vision herbicide on mortality, avoidance response, and growth of amphibian larvae in two forest wetlands.	the effects of vision (glyphosate, 356 mg acid equivalents (a.e.)/l) on mortality, avoidance response, and growth of larval amphibians (rana clamitans and rana pipiens) were investigated using in situ enclosures deployed in two forest wetlands of northern ontario, canada. in addition to untreated controls, vision was applied to yield initial concentrations ranging from 0.29 to 14.3 mg a.e./l (0.94-46.1 mg/l of vision). resultant 96-h median lethal concentration (lc50) values ranged from 2.70 to ...	2004	15095877
chemical and biomonitoring to assess potential acute effects of vision herbicide on native amphibian larvae in forest wetlands.	in conjunction with operational forest herbicide spray programs in ontario, canada, chemical and biological monitoring studies were conducted in 51 different wetlands to quantify the probability and magnitude of contamination by a glyphosate herbicide formulation (vision). wetlands were classified as oversprayed, adjacent, or buffered in relation to the operational target spray blocks. results show that vegetated buffers significantly mitigated against exposure and thus potential for acute effec ...	2004	15095878
effects of atrazine on metamorphosis, growth, and gonadal development in the green frog (rana clamitans).	embryos of the green frog (rana clamitans) were collected from the field and exposed to 1 of 6 water-borne treatments for 273 d (mid july 2001 to mid april 2002). the treatments were 0, 10, or 25 microg/l atrazine, 0.005% ethanol (etoh), or 0.1 mg/l estradiol or dihydrotestosterone carried in 0.005% etoh. treatments were applied in a static renewal system with a 50% test solution replacement approximately every 3 d. following the exposure period, tadpoles were reared in freshwater until metamorp ...	2004	15205037
survivorship patterns of larval amphibians exposed to low concentrations of atrazine.	amphibians can be exposed to contaminants in nature by many routes, but perhaps the most likely route is agricultural runoff in amphibian breeding sites. this runoff results in high-level pulses of pesticides. for example, atrazine, the most widely used pesticide in the united states, can be present at several parts per million in agricultural runoff. however, pesticide levels are likely to remain in the environment at low levels for longer periods. nevertheless, most studies designed to examine ...	2004	15238276
foraging behaviour in tadpoles of the bronze frog rana temporalis: experimental evidence for the ideal free distribution.	the ability of bronze frog rana temporalis tadpoles (pure or mixed parental lines) to assess the profitability of food habitats and distribute themselves accordingly was tested experimentally using a rectangular choice tank with a non- continuous input design. food (boiled spinach) was placed at two opposite ends of the choice tank in a desired ratio (1 : 1, 1 : 2 or 1 : 4) to create habitat a and b. the tadpoles in gosner stage 28-33, pre-starved for 24 h, were introduced in an open ended mesh ...	2004	15286417
toxicity of glyphosate-based pesticides to four north american frog species.	glyphosate-based herbicides are among the most widely used pesticides in the world. we compared the acute toxicity of the glyphosate end-use formulation roundup original to four north american amphibian species (rana clamitans, r. pipiens, r. sylvatica, and bufo americanus) and the toxicity of glyphosate technical, the polyethoxylated tallowamine surfactant (poea) commonly used in glyphosate-based herbicides, and five newer glyphosate formulations to r. clamitans. for r. clamitans, acute toxicit ...	2004	15352482
folic acid analogs in lower animals. the amphibia: rana clamitans.		1950	15433152
cytochrome p450 activity in green frogs (rana clamitans melanota) exposed to water and sediments in the fox river and green bay, wisconsin, usa.		2004	15674707
field exposure of frog embryos and tadpoles along a pollution gradient in the fox river and green bay ecosystem in wisconsin, usa.	we raised embryos and tadpoles of green frogs (rana clamitans melanota) and leopard frogs (r. pipiens) in situ along a contamination gradient in the fox river/green bay ecosystem (wi, usa). differences in exposure were reflected by significant positive regressions between concentrations in sediment and in frogs of polychlorinated biphenyl (pcb) congeners and some heavy metals (cd, cr, and pb), which could have predictive value for estimating exposure of amphibians to contaminants in this ecosyst ...	2005	15839570
multiple sublethal chemicals negatively affect tadpoles of the green frog, rana clamitans.	many habitats may be exposed to multiple chemical contaminants, particularly in agricultural areas where fertilizer and pesticide use are common; however, the singular and interactive effects of contaminants are not well understood. the objective of our study was to examine how realistic, sublethal environmental levels of ammonium nitrate fertilizer (0, 10, 20 mg/l and ammonium chloride control) and the common insecticide carbaryl (0 or 2.5 mg/l) individually and interactively affect the develop ...	2005	16111010
influence of larval period on responses of overwintering green frog (rana clamitans) larvae exposed to contaminated sediments.	pond-breeding amphibians exhibit large intra- and interspecific differences in the duration of the aquatic larval phase. in contaminated aquatic environments, a prolonged larval phase means prolonged exposure to pollutants and, potentially, more severe toxic effects. in the laboratory, we tested this hypothesis by exposing green frog larvae (rana clamitans) to commercial clean sand (control), sediment from an abandoned surface mine (mine), or sediment contaminated with coal combustion waste (ccw ...	2005	16117129
effects of the synthetic estrogen ethinylestradiol on early life stages of mink frogs and green frogs in the wild and in situ.	estrogenic contaminants are known to disrupt growth and development in amphibians. field-based research is needed to elucidate their potential impacts on wild populations. hatch success, larval growth and development rates, and gonad development were examined in native amphibians exposed to low ng/l concentrations of 17alpha-ethinylestradiol (ee2) in a whole-lake addition experiment at the experimental lakes area, northwestern ontario, canada. egg masses were reared in situ in the ee2-amended la ...	2005	16152976
effect of release herbicide on mortality, avoidance response, and growth of amphibian larvae in two forest wetlands.	effects of release herbicide (triclopyr butoxyethyl ester, [tbee]) on mortality, avoidance response, and growth of larval amphibians (rana clamitans, rana pipiens) were investigated using in situ enclosures deployed in two forest wetlands in northern ontario, canada. release was applied at nominal concentrations ranging from 0.26 to 7.68 mg tbee acid equivalents (ae)/l. no significant deleterious effects of this herbicide on larval growth were detected. however, concentration-dependent mortality ...	2005	16268155
atrazine concentrations, gonadal gross morphology and histology in ranid frogs collected in michigan agricultural areas.	the triazine herbicide atrazine has been suggested to be a potential disruptor of normal sexual development in male frogs. the goals of this study were to collect native ranid frogs from sites in agricultural and non-agricultural areas and determine whether hypothesised atrazine effects on the gonads could be observed at the gross morphological and histological levels. juvenile and adult green frogs (rana clamitans), bullfrogs (r. catesbeiana) and leopard frogs (r. pipiens) were collected in the ...	2006	16300839
plasma steroid hormone concentrations, aromatase activities and gsi in ranid frogs collected from agricultural and non-agricultural sites in michigan (usa).	the triazine herbicide atrazine has been hypothesized to disrupt sexual development in frogs by up-regulating aromatase activity, resulting in greater estradiol (e2) concentrations and causing feminization in males. the goal of this study was to collect native ranid frogs from atrazine-exposed ponds and determine whether relationships exist between measured atrazine concentrations and the gonadosomatic index (gsi), plasma concentrations of testosterone (t), e2 or 11-ketotestosterone (kt), or wit ...	2006	16427146
effects of atrazine on cercarial longevity, activity, and infectivity.	susceptibility of free-living infective stages of parasites to contaminants is relatively understudied compared with independent effects on measures of host health or immunity, but may be important in affecting prevalence and intensity of parasite infections. we investigated whether atrazine, an herbicide commonly used in north america, affected the cercariae of 4 different species of digenetic trematodes, and found that effects of atrazine concentration on mortality and activity of cercariae va ...	2006	16729687
determination of polychlorinated biphenyl and polycyclic aromatic hydrocarbon elimination rates in adult green and leopard frogs.	the purpose of the present study was to quantify elimination kinetics of polychlorinated biphenyls (pcbs) and polycyclic aromatic hydrocarbons (pahs) in adult green frogs (rana clamitans) and leopard frogs (rana pipiens). three experiments were conducted: pcb elimination rate constants were determined for both frog species, and pah elimination rate constants were determined for leopard frogs only. in green frogs, significant pcb elimination rate constants ranged from 0.013 to 0.04 d(-1) (time fo ...	2006	16764482
sediment tcdd-eqs and erod and mrod activities in ranid frogs from agricultural and nonagricultural sites in michigan (usa).	in vitro studies have demonstrated atrazine-mediated induction of 7-ethoxyresorufin o-deethylase (erod) activity. erod is an enzyme active in the metabolism of many compounds, including many xenobiotics. these studies have suggested that atrazine may affect reproductive function by altering steroid metabolism. the goal of this study was to determine whether relationships could be detected between measured atrazine concentrations in surface waters and the liver-somatic index (lsi) and erod and 7- ...	2006	16788744
impact of atrazine on chlorpyrifos toxicity in four aquatic vertebrates.	atrazine has been shown previously to potentiate chlorpyrifos toxicity in selected invertebrates. this study examined interactions of atrazine and chlorpyrifos in four aquatic vertebrates. organisms were exposed to binary mixtures of atrazine and chlorpyrifos during toxicity bioassays. inhibition of cholinesterase (che) enzyme activity and chlorpyrifos uptake kinetics were also examined with and without atrazine exposure. atrazine alone did not affect organisms at concentrations up to 5000 micro ...	2006	16944040
peptidomic analysis of skin secretions from rana heckscheri and rana okaloosae provides insight into phylogenetic relationships among frogs of the aquarana species group.	the members of the aquarana (or rana catesbeiana species group) form a monophyletic group comprising seven species: r. catesbeiana, rana clamitans, rana grylio, rana virgatipes, rana septentrionalis, rana heckscheri and rana okaloosae. previous work has led to structural characterization of the antimicrobial peptides present in electrically-stimulated skin secretions from the first five species listed and this study presents the primary structures of orthologs from the river frog r. heckscheri a ...	2007	17005262
metamorphosis increases biotransformation of polychlorinated biphenyls: a comparative study of polychlorinated biphenyl metabolism in green frogs (rana clamitans) and leopard frogs (rana pipiens) at various life stages.	polychlorinated biphenyl (pcb) elimination rates were used to determine whether green frogs (rana clamitans) and leopard frogs (rana pipiens) at three life stages (tadpole, metamorph, and adult) were capable of metabolic biotransformation of pcbs. polychlorinated biphenyls were grouped according to their structural properties to determine whether congeners with specific structures were eliminated more rapidly than others, which would suggest the occurrence of metabolic biotransformation. for bot ...	2006	17089721
phenotypically plastic responses of green frog embryos to conflicting predation risk.	predators have been shown to alter the timing of switch points between life history stages, but few studies have addressed switch point plasticity in prey exposed simultaneously to conflicting predation pressure. we tested hatching responses of green frog (rana clamitans) embryos subject to perceived predation risk from chemical cues released by two stage-specific predators, predicting that these predators would elicit: (1) directional hatching responses when presented independently, and (2) int ...	2007	17216211
bioremediation of tetrachloroethylene-contaminated groundwater in a model aquifer: effects on green frogs (rana clamitans) and xenopus laevis as potential wetland receptors.	recent regulations require that the ecological effects of microorganisms introduced into the environment, such as for groundwater bioremediation, be assessed prior to their utilization. a native anuran (rana clamitans) and a model anuran (xenopus laevis) were used as potential wetland receptors of tetrachloroethylene (pce)-contaminated groundwater, undergoing three bioremediation treatments: natural attenuation (na), biostimulation (st), and bioaugmentation (au). eggs of both species were expose ...	2007	17253100
mercury bioaccumulation in green frog (rana clamitans) and bullfrog (rana catesbeiana) tadpoles from acadia national park, maine, usa.	mercury contamination in the northeastern united states, including acadia national park (anp; me, usa), is well documented and continues to be a public health issue of concern. mercury contamination of wild amphibians has received little attention, however, despite reports of worldwide population declines. here, we report total hg and methyl hg (mehg) concentrations for water, sediment, and green frog (rana clamitans) and bullfrog (rana catesbeiana) tadpoles (age, approximately one year) from an ...	2007	17269468
polychlorinated biphenyls and organochlorine pesticides bioaccumulated in green frogs, rana clamitans, from the lower fraser valley, british columbia, canada.	seven adult green frogs (rana clamitans) were collected from three sites adjacent to intensive agriculture in the lower fraser river valley, bc canada. the highest mean concentrations of chemicals were pp'dde at 0.313 microg/g lipid wt. and aroclor 1,254/1,260 at 2.12 microg/g lipid wt. on a lipid weight basis, both pp'dde and pcb concentrations varied by almost an order of magnitude among sites. only ortho-substituted pcb congeners were detected. the concentrations of organochlorine pesticides ...	2007	17639331
frog virus 3 prevalence in tadpole populations inhabiting cattle-access and non-access wetlands in tennessee, usa.	ranaviruses have been associated with most of the reported larval anuran die-offs in the united states. it is hypothesized that anthropogenically induced stress may increase pathogen prevalence in amphibian populations by compromising immunity. cattle use of wetlands may stress resident tadpole populations by reducing water quality. we isolated a ranavirus from green frog rana clamitans (n = 80) and american bullfrog r. catesbeiana (n = 104) tadpoles collected at 5 cattle-access and 3 non-access ...	2007	17972750
studies on hypophysectomized second year rana clamitans larvae.		1948	18101416
4-amino pteroylglutamic acid, pteroylglutamic acid, and response of frogs, rana clamitans, to estrogens.		1948	18102210
the influence of the circadian rhythm of green frog (rana clamitans) tadpoles on their antipredator behavior and the strength of the nonlethal effects of predators.	prey trade off predation risk and foraging gain in their activity level. their response to this trade-off mediates direct and indirect interactions between predators and the community (i.e., nonlethal effects). a prey's activity level may also vary independently because of circadian rhythms. i tested how the antipredator behavior of green frog (rana clamitans) tadpoles can be influenced by their circadian rhythm (primarily nocturnal feeding) and how the strengths of nonlethal effects vary in tur ...	2008	18241009
examining the single and interactive effects of three insecticides on amphibian metamorphosis.	although aquatic communities frequently are exposed to a number of pesticides, the effects of chemical mixtures are not well understood. in two separate studies, i examined how insecticide mixtures influenced the likelihood of unpredictable, nonadditive effects on american toad (bufo americanus) and green frog (rana clamitans) tadpoles reared in outdoor aquatic communities. i exposed tadpoles to single or multiple insecticides at approximately half the reported median lethal concentrations using ...	2008	18260698
the dynamics of predation risk assessment: responses of anuran larvae to chemical cues of predators.	1. while the antipredator behaviour of prey has been well studied, little is known about the rules governing the predation risk assessment of prey. in this study, i measured the activity levels of predator-naive green frog (rana clamitans) tadpoles during and after exposures to the chemical cue of predatory larval dragonflies (anax spp.). i then used the lengths of the time lags from the end of the cue exposures until the tadpoles returned to a control level of activity as an index of the percei ...	2008	18397251
effects of timber harvesting on pond-breeding amphibian persistence: testing the evacuation hypothesis.	numerous studies have documented the decline of amphibians following timber harvest. however, direct evidence concerning the mechanisms of population decline is lacking and hinders attempts to develop conservation or recovery plans and solutions for forest species. we summarized the mechanisms by which abundance of amphibians may initially decline following timber harvest into three testable hypotheses: (1) mortality, (2) retreat, and (3) evacuation. here, we tested the evacuation hypothesis wit ...	2008	18488596
effects of nitrate on embryos of three amphibian species.	embryos of three aquatic breeding amphibian species, ambystoma mexicanum, hyla chrysoscelis, and rana clamitans, were exposed to increasing levels (0, 5, 10, 30, 60, 100, 300, and 500 mg/l) of nitrate-n (no(3)-) in laboratory, static-renewal experiments. lethal effects were recorded from gosner stage 2 (h. chrysoscelis and r. clamitans) or harrison stage 2 (a. mexicanum) to time of hatching. date of hatching and length at hatching were also compared between treatments for a. mexicanum. no signif ...	2008	18496633
potential endocrine disruption of sexual development in free ranging male northern leopard frogs (rana pipiens) and green frogs (rana clamitans) from areas of intensive row crop agriculture.	intensive row crop agriculture (irca) for corn and soybean production is predominant in eastern and central north america. irca relies heavily on pesticide and nutrient inputs to maximize production under conventional systems. in 2003-2005, we assessed the occurrence of a suite of potential endocrine effects in amphibians inhabiting farm ponds and agricultural drains in irca areas of southwestern ontario. effects were compared to amphibians from two agricultural reference sites as well as four n ...	2008	18582957
incongruence in the pattern and timing of intra-specific diversification in bronze frogs and bullfrogs (ranidae).	we compare patterns of lineage divergence in mitochondrial dna (mtdna) sequences of two protein-encoding mitochondrial genes (cyt b and nd2) in two ecologically similar, co-distributed, and closely related ranid frogs (rana clamitans and rana catesbeiana), that are geographically widespread, and frequently syntopic. we identified three lineages in r. clamitans, separated by 0.5% to 2.1% net corrected sequence divergence, comparable to two r. catesbeiana lineages separated by 0.6%. the geographic ...	2008	18625326
toxicity of road salt to nova scotia amphibians.	the deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. in northern latitudes, a major pollutant in runoff water is salt (nacl), used as de-icing agents. in this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. acute toxicity tests (lc(50)) were performed on five locally common amphibian species using a range of environmentally significant nacl concentrations. field surveys indicated that spotte ...	2009	18684543
understanding the net effects of pesticides on amphibian trematode infections.	anthropogenic factors can have simultaneous positive and negative effects on parasite transmission, and thus it is important to quantify their net effects on disease risk. net effects will be a product of changes in the survival and traits (e.g., susceptibility, infectivity) of both hosts and parasites. in separate laboratory experiments, we exposed cercariae of the trematode echinostoma trivolvis, and its first and second intermediate hosts, snails (planorbella trivolvis) and green frog tadpole ...	2008	18839768