Journal articles: 'Bullfrogs'

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Flynn, Lauren, Tess Kreofsky, and Adam Sepulveda. "Introduced American Bullfrog Distribution and Diets in Grand Teton National Park." UW National Parks Service Research Station Annual Reports 38 (January 1, 2015): 17–28. http://dx.doi.org/10.13001/uwnpsrc.2015.4081.

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Introduced American Bullfrogs (Lithobates catesbeianus) have been present in Grand Teton National Park since approximately the 1950s, but little is known about their distribution and potential impacts. In this study, we surveyed the current bullfrog distribution and spatial overlap with sympatric native amphibians in the park, and characterized post-metamorphic bullfrog diets from July â September 2015. Despite surveys in multiple large rivers and floodplain habitats, we only documented bullfrogs in a geothermal pond and 5 km of stream channel immediately downstream of this pond. In these waters, bullfrogs overlapped with native amphibians at the downstream end of their distribution, and we did not document native amphibians in bullfrog stomach contents. Larger bullfrogs (SVL â¥ 96 mm) primarily consumed native rodents (especially meadow voles, Microtus pennsylvanicus), while smaller bullfrogs frequently consumed native invertebrates and less frequently consumed non-native invertebrates and fish. Taken together, these data indicate that the distribution and implications of the bullfrog invasion in Grand Teton National Park are currently localized to a small area, so these bullfrogs should therefore be vulnerable to eradication.

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Garner, Trenton W. J., Matthew W. Perkins, Purnima Govindarajulu, Daniele Seglie, Susan Walker, Andrew A. Cunningham, and Matthew C. Fisher. "The emerging amphibian pathogen Batrachochytrium dendrobatidis globally infects introduced populations of the North American bullfrog, Rana catesbeiana." Biology Letters 2, no. 3 (May 24, 2006): 455–59. http://dx.doi.org/10.1098/rsbl.2006.0494.

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Batrachochytrium dendrobatidis is the chytridiomycete fungus which has been implicated in global amphibian declines and numerous species extinctions. Here, we show that introduced North American bullfrogs ( Rana catesbeiana ) consistently carry this emerging pathogenic fungus. We detected infections by this fungus on introduced bullfrogs from seven of eight countries using both PCR and microscopic techniques. Only native bullfrogs from eastern Canada and introduced bullfrogs from Japan showed no sign of infection. The bullfrog is the most commonly farmed amphibian, and escapes and subsequent establishment of feral populations regularly occur. These factors taken together with our study suggest that the global threat of B. dendrobatidis disease transmission posed by bullfrogs is significant.

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MEDEIROS, CAMILA I., CAMILA BOTH, IGOR L. KAEFER, and SONIA Z. CECHIN. "Reproductive phenology of the American Bullfrog in subtropical Brazil: photoperiod as a main determinant of seasonal activity." Anais da Academia Brasileira de Ciências 88, no. 3 suppl (July 11, 2016): 1909–21. http://dx.doi.org/10.1590/0001-3765201620150694.

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ABSTRACT The North American bullfrog Lithobates catesbeianus continues to invade ecosystems worldwide, potentially causing population declines and even extinctions. Within its native distribution, bullfrogs show prolonged reproductive seasons and high fertility. However, data on breeding biology of bullfrogs ex-situ in invaded localities mainly comes from anecdotal reports. Understanding how invasive species are adjusting their life histories to new colonized environments is important for conservation purposes. Here we describe temporal and spatial abundance, calling activity, spawning and tadpole distribution of bullfrogs in southern Brazil. Eighteen samplings occurred during one year. The abundance of individuals was positively related to longer photoperiods and higher temperatures. Reproductive activity was also positively associated with longer photoperiods. Calling sites, spawning and tadpoles were associated with microhabitats presenting hydrophytes, which may provide shelter and thermal stability to bullfrogs. The reproductive seasonal activity of bullfrogs can be highly variable across its growing geographical range, but in subtropical Brazil it is associated with photoperiod, a highly predictable abiotic determinant. In our study area, bullfrogs presented a breeding season twice as long as that observed in some native localities. We suggest that management strategies directed to bullfrog populations must consider the habitat structures and seasonal regimes determined by each invaded environment.

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Kamoroff, Colleen, Ninette Daniele, Robert L. Grasso, Rebecca Rising, Travis Espinoza, and Caren S. Goldberg. "Effective removal of the American bullfrog (Lithobates catesbeianus) on a landscape level: long term monitoring and removal efforts in Yosemite Valley, Yosemite National Park." Biological Invasions 22, no. 2 (October 22, 2019): 617–26. http://dx.doi.org/10.1007/s10530-019-02116-4.

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Abstract Invasive alien species are a major threat to freshwater ecosystems, and American bullfrogs are among the world’s 100 most prominent aquatic invasive species causing negative direct and indirect effect on native aquatic fauna worldwide. Bullfrogs were intentionally introduced into Yosemite Valley, Yosemite National Park in the 1950s where they became well established in the subsequent years. Starting in 2005, the National Park Service (NPS) began bullfrog removal, targeting various life stages using hand, net, and spear techniques. Starting in 2015, the NPS conducted environmental DNA (eDNA) surveys and deployed audio recordings devices to ensure adequate detection of bullfrogs. During the first year of cencerted effort in the Valley in 2005, the NPS removed 86% of all recorded bullfrog. The subsequent decade was spent searching for individuals with lower return on effort. In 2012, the NPS removed the last observed signs of bullfrog breeding, and the last observed bullfrog in 2019. Following removal of the breeding bullfrog population, the NPS began restoration projects for species of special concern. The NPS introduced the federally threatened California red-legged frogs (Rana draytonii) into Yosemite Valley beginning in 2016. This is the first published successful eradication of bullfrogs on a landscape level. National Parks and Monuments often provide refuges for imperiled wildlife and should be managed to remove invasive species. Our work highlights effective bullfrog removal is obtainable and can lead to local recovery of endangered species.

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Snow, Nathan P., and GAry W. Witmer. "A field evaluation of a trap for invasive American bullfrogs." Pacific Conservation Biology 17, no. 3 (2011): 285. http://dx.doi.org/10.1071/pc110285.

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Native to the eastern United States, American bullfrogs (Rana catesbeiana [Lithobates catesbeianus]) have been introduced in many countries throughout the world. There have been relatively few effective and efficient control methods developed to manage bullfrogs. Particularly in the Hawaiian Islands, Pacific coast of North America, and Japan, finding effective methods for controlling invasive bullfrogs is needed with special emphasis on low impacts for sensitive native species. We conducted a field study to examine the efficacy of a newly designed live trap for capturing invasive bullfrogs. We found that our trap was successful at capturing bullfrogs because we captured up to seven in a single trap overnight. Fishing lures, live crickets, and lights were used as attractants and all capture bullfrogs, however more research is needed for finding effective attractants. We captured one known non-target frog that was released. Our findings suggest that the multiple capture traps could effectively be used as part of an integrated pest management strategy for controlling invasive bullfrog populations.

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Boelter, Ruben A., Igor L. Kaefer, Camila Both, and Sonia Cechin. "Invasive bullfrogs as predators in a Neotropical assemblage: What frog species do they eat?" Animal Biology 62, no. 4 (2012): 397–408. http://dx.doi.org/10.1163/157075612x634111.

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Anurans are important prey for the American bullfrog Lithobates catesbeianus, but field assessments of its diet in the context of a local prey assemblage are lacking. We aimed to identify the frog species consumed by an invasive bullfrog population in subtropical South America, and to assess their relative importance among other types of prey. Characterization of the frog assemblage in the study area also allowed us to calculate the degree of electivity of the recorded anuran prey, in order to gain insight regarding bullfrog feeding preferences and to test if the bullfrog prey composition differed from a random sample of the assemblage. A total of 32.6% of the bullfrogs had at least one anuran in the stomach contents, and post-metamorphic anurans represented 49.1% of the relative prey importance for adult bullfrogs. Anurans were preyed on by all size classes, and constituted the volumetrically most important prey category in the diet of individuals heavier than 100 g. Cycloramphidae, Hylidae and Leiuperidae were positively selected, and Hypsiboas pulchellus and Physalaemus cuvieri were the species most often taken. We found a low occurrence of cannibalism, despite the high density of bullfrogs at the study site. Our results showed that the degree of electivity differed among bullfrog prey types, suggesting that some frog species may be preyed on in a higher proportion than their relative abundance in the assemblage. Testing the clues provided by this assemblage-level approach may lead to a better assessment of the interactions between bullfrogs and the native frog fauna.

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Atobe, Takashi, Yutaka Osada, Hayato Takeda, Misako Kuroe, and Tadashi Miyashita. "Habitat connectivity and resident shared predators determine the impact of invasive bullfrogs on native frogs in farm ponds." Proceedings of the Royal Society B: Biological Sciences 281, no. 1786 (July 7, 2014): 20132621. http://dx.doi.org/10.1098/rspb.2013.2621.

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Habitat connectivity is considered to have an important role on the persistence of populations in the face of habitat fragmentation, in particular, for species with conservation concern. However, it can also impose indirect negative effects on native species through the spread of invasive species. Here, we investigated direct and indirect effects of habitat connectivity on populations of invasive bullfrogs and native wrinkled frogs and how these effects are modified by the presence of common carp, a resident shared predator, in a farm pond system in Japan. The distribution pattern analysis using a hierarchical Bayesian modelling indicated that bullfrogs had negative effects on wrinkled frogs, and that these negative effects were enhanced with increasing habitat connectivity owing to the metapopulation structure of bullfrogs. The analysis also suggested that common carp mitigated these impacts, presumably owing to a top-down trophic cascade through preferential predation on bullfrog tadpoles. These presumed interspecific interactions were supported by evidence from laboratory experiments, i.e. predation by carp was more intense on bullfrog tadpoles than on wrinkled frog tadpoles owing to the difference in refuge use. Our results indicate that metacommunity perspectives could provide useful insights for establishing effective management strategies of invasive species living in patchy habitats.

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Courtois, Daniel, Raymond Leclair jr., Sylvain Lacasse, and Pierre Magnan. "Habitats préférentiels d'amphibiens ranidés dans des lacs oligotrophes du Bouclier laurentien, Québec." Canadian Journal of Zoology 73, no. 9 (September 1, 1995): 1744–53. http://dx.doi.org/10.1139/z95-206.

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From a study of riparian habitat structure and a quantitive distribution survey of bullfrog, Rana catesbeiana, mink frog, Rana septentrionalis, and green frog, Rana clamitans melanota, in 31 oligotrophic lakes, we looked for, among 18 physiographic parameters, those that could best explain the spatial organisation of the ranid community. The three species cohabitated in 18 lakes, the mink frog and the green frog in 10 lakes without bullfrog, and the bullfrog alone in 3 lakes. These frogs preferentially occupied (i) habitats with medium or high density of emergent vegetation, (ii) areas with extensive floating aquatic vegetation, (iii) muddy and silty areas, and (iv) especially for the green frog, shrubby habitats with ericaceae. Substrates had a poor explicative value. In lakes devoid of bullfrogs, the mink frogs and green frogs were more frequently abundant and showed a more even distribution in the different habitats than when they were sympatric with bullfrogs. A Spearman's rank correlation analysis confirmed the similarity of habitat preferences between the three species and the poor capacity of the habitat structure to predict the ranid community composition.

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McAlpine, Donald F. "Helminth communities in bullfrogs (Rana catesbeiana), green frogs (Rana clamitans), and leopard frogs (Rana pipiens) from New Brunswick, Canada." Canadian Journal of Zoology 75, no. 11 (November 1, 1997): 1883–90. http://dx.doi.org/10.1139/z97-818.

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Twenty-three helminth species were identified from bullfrogs, Rana catesbeiana, green frogs, R. clamitans, and leopard frogs, R. pipiens, in New Brunswick. Digeneans dominated adult helminth communities in the aquatic bullfrog and semi-aquatic green frog; nematodes were dominant in the more terrestrial leopard frog. In green frogs and leopard frogs, richness and abundance were greatest in adults; in bullfrogs, juveniles showed the greatest richness and abundance. An increase in vertebrates in the diet of adult bullfrogs influences helminth communities in bullfrogs. Where Glypthelmins quieta and nematodes, which infect the host by skin penetration, predominate in green frogs and leopard frogs, respectively, the increase in epidermal area with age probably influences helminth abundance. Adult female leopard frogs are larger than males and harbour greater numbers of helminths. Within the most heavily sampled component communities only larval digeneans, and less frequently nematodes with direct life cycles, were common (i.e., in > 50% of hosts); other taxa were generally present at prevalences of < 20% and intensities of < 10 helminths per frog. Although wetland characteristics and helminth transmission dynamics play a role in producing variation in helminth communities among sites, ontogenetic shifts in diet and sexual size dimorphism within these anuran species are important in shaping helminth communities in individual frog hosts.

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Braga, Luís Gustavo Tavares, Maria Goreti de Almeida Oliveira, William Cardoso Lima, and Ricardo Frederico Euclydes. "Enzymatic activity of lipase in post-metamorphic phase bullfrogs." Scientia Agricola 63, no. 5 (October 2006): 439–43. http://dx.doi.org/10.1590/s0103-90162006000500004.

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The knowledge of the digestive system of bullfrogs is an important step for the determination of their nutritional requirements throughout growth phases. With the objective of evaluating the enzymatic activity of lipase in the intestinal content of bullfrogs (Rana catesbeiana Shaw, 1802), 100 animals with median weight of 3.6 g were distributed in stalls under controlled temperature and photoperiod. The frogs, selected at the post-metamorphic phase, received commercial extruded diet ad libitum throughout the 87-day experiment. The collections of the intestinal content were performed by the desensitization of the frogs in ice and water at 0ºC and subsequent isolation of the small intestine. Determination of lipase activity was performed with a commercial enzymatic kit (Lipase-Bioclin, MG, Brazil), first measured in samples taken at day three (3.46 UI). During the initial phase the bullfrog possesses low lipase hydrolysis capacity was found, having a specific activity of 217 UI mg-1. In the subsequent period both lipase activity and specific lipase activity continuously increased. Lipase activity as a function of bullfrog weight fell after day twenty and reached 0.33 UI g-1, for frogs of medium weight (179 g). Feed for bullfrogs at the post-metamorphic phase weighing more than 10 g can have larger amounts of ingredients containg lipids, due to the increased digestive capacity of these frogs.

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Nicholson, E. Griffin, Stephanie Manzo, Zachary Devereux, Thomas Paul Morgan, Robert N. Fisher, Christopher Brown, Rosi Dagit, Peter A. Scott, and H. Bradley Shaffer. "Historical museum collections and contemporary population studies implicate roads and introduced predatory bullfrogs in the decline of western pond turtles." PeerJ 8 (June 12, 2020): e9248. http://dx.doi.org/10.7717/peerj.9248.

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The western pond turtle (WPT), recently separated into two paripatrically distributed species (Emys pallida and Emys marmorata), is experiencing significant reductions in its range and population size. In addition to habitat loss, two potential causes of decline are female-biased road mortality and high juvenile mortality from non-native predatory bullfrogs (Rana catesbeiana). However, quantitative analyses of these threats have never been conducted for either species of WPT. We used a combination of historical museum samples and published and unpublished field studies shared with us through personal communications with WPT field researchers (B. Shaffer, P. Scott, R. Fisher, C. Brown, R. Dagit, L. Patterson, T. Engstrom, 2019, personal communications) to quantify the effect of roads and bullfrogs on WPT populations along the west coast of the United States. Both species of WPT shift toward increasingly male biased museum collections over the last century, a trend consistent with increasing, female-biased road mortality. Recent WPT population studies revealed that road density and proximity were significantly associated with increasingly male-biased sex ratios, further suggesting female-biased road mortality. The mean body size of museum collections of E. marmorata, but not E. pallida, has increased over the last 100 years, consistent with reduced recruitment and aging populations that could be driven by invasive predators. Contemporary WPT population sites that co-occur with bullfrogs had significantly greater average body sizes than population sites without bullfrogs, suggesting strong bullfrog predation on small WPT hatchlings and juveniles. Overall, our findings indicate that both species of WPT face demographic challenges which would have been difficult to document without the use of both historical data from natural history collections and contemporary demographic field data. Although correlational, our analyses suggest that female-biased road mortality and predation on small turtles by non-native bullfrogs are occurring, and that conservation strategies reducing both may be important for WPT recovery.

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McAlpine, Donald F., and Timothy G. Dilworth. "Microhabitat and prey size among three species of Rana (Anura: Ranidae) sympatric in eastern Canada." Canadian Journal of Zoology 67, no. 9 (September 1, 1989): 2244–52. http://dx.doi.org/10.1139/z89-317.

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Microhabitat, prey size, and body morphology were examined in sympatric leopard frogs (Rana pipiens), green frogs (R. clamitans), and bullfrogs (R. catesbeiana) at a site in central New Brunswick. Ratios of head widths among species pairs were 1.23 (leopard and green frogs) and 1.51 (bullfrogs and green frogs), suggesting that leopard and green frogs may take prey of similar size. Analysis of stomach contents showed no significant differences in the mean prey sizes selected by leopard and green frogs. Rana sp. figured prominently in the diet of bullfrogs at the study site. Overlap among the species for prey length indicates the potential for competition between green and leopard frogs (Pij = 0.40 versus Pij = 1.41 for green frogs and bullfrogs). Structural aspects of habitat associated with vegetation were most important in discriminating microhabitat. Leopard frogs selected microhabitats that were much more densely vegetated than those of either bullfrogs or green frogs. In water, green frogs occupied sites that were closer to shore, were of lower water temperature, and had a higher vegetation canopy than sites occupied by bullfrogs. On land, green frogs selected microhabitats that were closer to water and less densely vegetated than those of leopard frogs. There was much greater microhabitat separation between leopard and green frogs than between green frogs and bullfrogs. There is some evidence that predation (bullfrogs preying on green frogs) and perhaps past competition (between green frogs and leopard frogs) have contributed to the patterns of resource use described. A number of other potential mechanisms (i.e., species phylogenies, inherent physiological or behavioural constraints acquired independently of interspecific interactions) remain unevaluated.

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Dare, O. K., and M. R. Forbes. "Do invasive bullfrogs in Victoria, British Columbia, Canada, show evidence of parasite release?" Journal of Helminthology 87, no. 2 (April 12, 2012): 195–202. http://dx.doi.org/10.1017/s0022149x12000211.

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AbstractFew studies have examined vertebrate models of invasive species to explore parasite release as a proposed mechanism through which host species might become invasive. In this study, we examined evidence for parasite release in invasive American bullfrogs (Rana catesbeiana/Lithobates catesbeianus) from five sites in Victoria, British Columbia, Canada. We examined helminth species richness, as well as the prevalence, intensity and abundance of lung and kidney fluke infections. These flukes are expected to impose costs on host survival, growth and reproductive output. We compared measures of these parasite taxa with bullfrogs from Ontario and New Brunswick where they are endemic. Helminth species richness in bullfrogs from the Victoria sites was lower than in Ontario bullfrogs, but comparable to reported indices for other endemic populations. The prevalence of lung flukes (Haematoloechusspp.) in bullfrogs from Victoria was twice as high as was observed in the Ontario bullfrogs, and higher than has been reported from other endemic locations. In four of the five study sites in Victoria, numbers ofEchinostomaspp. kidney cysts were lower than observed in endemic populations; however, the fifth site had uncharacteristically high numbers of cysts. In this study, there did not appear to be clear evidence to support parasite release using either parasite species numbers, or infection by specific parasite taxa. Instead, the invasive bullfrogs demonstrated high parasite species richness and high levels of infection for parasites known to be harmful to their hosts.

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Pereira, Marcelo Maia, Cleber Fernando Menegasso Mansano, Edney Pereira da Silva, and Marta Verardino De Stéfani. "Growth in weight and of some tissues in the bullfrog: fitting nonlinear models during the fattening phase." Ciência e Agrotecnologia 38, no. 6 (December 2014): 598–606. http://dx.doi.org/10.1590/s1413-70542014000600009.

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Knowledge of the growth of animals is important so that zootechnical activity can be more accurate and sustainable. The objective of this study was to describe the live weight, development of liver tissue and fat body, leg growth, and cumulative food intake of bullfrogs during the fattening phase using nonlinear models. A total of 2,375 bullfrog froglets with an initial weight of 7.03 ± 0.16 g were housed in five fattening pens (12 m²). Ten samplings were performed at intervals of 14 days to obtain the variables studied. These data were used to estimate the parameters of Gompertz and logistic models as a function of time. The estimated values of weight (Wm) and food intake (FIm) at maturity and time when the growth rate is maximum (t*) were closer to expected values when the logistic model was used. The Wm values for live weight and liver, adipose and leg weights and the FIm value for food intake were 343.7, 15.7, 19.6, 96.03 and 369.3 g, respectively, with t* at 109, 98, 105, 109 and 107 days. Therefore, the logistic model was the best model to estimate the growth and food intake of bullfrogs during the fattening phase.

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Howell, Paige E., Erin Muths, Brent H. Sigafus, and Blake R. Hossack. "Survival estimates for the invasive American bullfrog." Amphibia-Reptilia 41, no. 4 (June 5, 2020): 559–64. http://dx.doi.org/10.1163/15685381-bja10016.

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Abstract American bullfrogs (Lithobates catesbeianus) are significant invaders in many places and can negatively impact native species. Despite their impact and wide distribution, little is known about their demography. We used five years of capture mark-recapture data to estimate annual apparent survival of post-metamorphic bullfrogs in a population on the Buenos Aires National Wildlife Refuge in their invaded range in Arizona, U.S.A. This population is a potential source of colonists into breeding ponds used by the federally threatened Chiricahua leopard frog (L. chiricahuensis). Results from robust-design Cormack-Jolly-Seber models suggested that survival of bullfrogs was influenced by sex and precipitation but not body condition. Survival was higher for females (mean = 0.37; 95% , 0.72) than males (mean = 0.17; 95% , 0.49), and declined with reduced annual precipitation (mean = −0.36, 95% = −2.09, 0.84). These survival estimates can be incorporated into models of population dynamics and to help predict spread of bullfrogs.

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Wilson, John X., Khaled J. Saleh, E. Davindra Armogan, and Ewa J. Jaworska. "Catecholamine and blood pressure regulation by gonadotropin-releasing hormone analogs in amphibians." Canadian Journal of Physiology and Pharmacology 65, no. 12 (December 1, 1987): 2379–85. http://dx.doi.org/10.1139/y87-377.

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Analogs of gonadotropin-releasing hormone (GnRH) occur in the brain, plasma, and sympathoadrenal system of anuran amphibians. The present experiments studied the effects of GnRH and [Trp7, Leu8]-GnRH on plasma catecholamines and cardiovascular function in conscious adult bullfrogs (Rana catesbeiana) and cane toads (Bufo marinus). Both GnRH analogs elicited dose-dependent (0.1–1 nmol∙kg−1) increases in arterial norepinephrine, epinephrine, and blood pressure levels when injected intravenously into toads. In bullfrogs, [Trp7, Leu8]-GnRH (1 nmol∙kg−1) increased arterial norepinephrine concentration approximately 10-fold without affecting the concentrations of norepinephrine sulfate, norepinephrine glucuronide, epinephrine, epinephrine sulfate, or epinephrine glucuronide. The noradrenergic response of bullfrogs to [Trp7, Leu8]-GnRH was specific to the neurohormone because it could be inhibited by [D-pGlu1, D-Phe2, D-Trp3,6]-GnRH. The sympathomimetic activities of the GnRH analogs did not depend on changes in temperature, which occur seasonally in natural habitats, because similar noradrenergic responses were observed at 4 and 22 °C. GnRH and [Trp7, Leu8]-GnRH (0.01–10 nmol∙kg−1) did not raise arterial blood pressure in bullfrogs despite their pressor actions in toads. This interspecific difference was remarkable because cardiovascular responses to norepinephrine, angiotensin II, and vasotocin in bullfrogs were similar to those in toads. The parallels between catecholamine and blood pressure responses suggest that epinephrine is the principal mediator of the blood pressure response to native GnRH analogs in toads. In bullfrogs, [Trp7, Leu8]-GnRH mobilizes norepinephrine but not epinephrine, and the noradrenergic effect is insufficient to raise blood pressure. These observations are consistent with a physiological role for native GnRH analogs in the regulation of the sympathoadrenal system in anuran amphibians.

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Takahashi, N., S. Kikuyama, K. Gen, O. Maruyama, and Y. Kato. "Cloning of a bullfrog growth hormone cDNA: expression of growth hormone mRNA in larval and adult bullfrog pituitaries." Journal of Molecular Endocrinology 9, no. 3 (December 1992): 283–89. http://dx.doi.org/10.1677/jme.0.0090283.

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ABSTRACT A GH cDNA was specifically amplified from cDNAs constructed from total RNA of bullfrog (Rana catesbeiana) adenohypophyses employing the DNA polymerase chain reaction. Sequencing analysis revealed that the cDNA clone thus obtained was 654 bp in length, and included an open reading frame encoding the entire sequence of mature GH, with its signal peptide. Slight discrepancies were noted between the deduced amino acid sequence and that determined by direct protein sequencing of purified bullfrog GH or that deduced from the nucleotide sequence reported previously. The length of the bullfrog GH mRNA was estimated to be about 1·2 kb by Northern blot analysis. Homologies of nucleotide and amino acid sequences between GH and prolactin of bullfrog origin were 48% and 26% respectively. Using the cDNA as a probe, the content of GH mRNA in the pituitary of larval and adult bullfrogs was measured. GH mRNA levels were relatively low at the preclimax stage, and rose markedly during climax. In juvenile frogs, GH mRNA levels in the pituitary were extremely high and declined towards adulthood. This finding suggests that the increase in plasma and pituitary GH levels reported previously accompanies the increase in GH synthesis.

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Pang, P. K., T. Kaneko, and S. Harvey. "Immunocytochemical distribution of PTH immunoreactivity in vertebrate brains." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 255, no. 4 (October 1, 1988): R643—R647. http://dx.doi.org/10.1152/ajpregu.1988.255.4.r643.

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Immunoreactive (IR) cell bodies, reacting with an antiserum specific for the 48-64 region of bovine parathyroid hormone (PTH), were detected in the brains of primitive vertebrates (hagfish), bullfrogs, and higher vertebrates (mice). In each species the IR perikarya were located in the preoptic region, although the precise location and abundance of IR perikarya differed among species. Fiber tracts from these IR perikarya were traced to the neurohypophysis in the hagfish but only to the median eminence in the bullfrog and mouse, where the axonal terminals were in close proximity to hypophyseal portal blood vessels. These results suggest that a novel PTH-like peptidergic system, similar to those secreting hypophysiotropic-releasing factors, is present in the vertebrate brain.

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Li, Yiming, Zhunwei Ke, Yihua Wang, and Tim M. Blackburn. "Frog community responses to recent American bullfrog invasions." Current Zoology 57, no. 1 (February 1, 2011): 83–92. http://dx.doi.org/10.1093/czoolo/57.1.83.

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Abstract Native species may decline quickly when confronted with an exotic species to which they are not adapted. The extent of decline may depend on the abundance of an invader and the length of time since it first arrived in the community (residence time), and the interaction between these two variables. We tested these effects using data on the effects of American bullfrog Lithobates catesbeianus invasion on native frog communities in 65 permanent lentic waters on islands in the Zhoushan Archipelago, China. We examined variation in native frog abundance and species richness in relation to features of the American bullfrog invasion, habitat disturbance, characteristics of the water body and fish communities and the presence of red swamp crayfish. Bullfrog invaded sites had lower native frog density and species richness, higher submerged vegetation cover and greater frequency of repairs to the water body than did non-invaded sites. The minimum adequate general linear mixed models showed that both native frog density and species richness were negatively related to post-metamorphosis bullfrog density, and that native frog species richness was also positively related to the vegetation cover. There was no effect on either native frog density or species richness of residence time or its interaction with bullfrog density, or of the abundance of bullfrog tadpoles. The results suggested that post-metamorphosis bullfrogs had impacts on native frog communities in the islands, and that the extents of these impacts are proportional to post-metamorphosis bullfrog density.

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Stéfani, Marta Verardino De, Marcelo Maia Pereira, Marcio Roberto Reche, and Cleber Fernando Menegasso Mansano. "Fecal collection methods for the determination of protein digestibility in bullfrogs." Ciência Rural 45, no. 8 (August 2015): 1492–95. http://dx.doi.org/10.1590/0103-8478cr20141369.

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Adequate methods for the determination of protein digestibility in bullfrogs are important for the understanding of nutrient utilization. Therefore, this study evaluated two methods of feces collection: intestinal dissection and fecal decantation, using cylindric-conical tanks. Frogs were fed with a commercial diet (45% crude protein) which was ground and supplemented with 0.5% chromium oxide III. The frogs were fasted 48h before force-feeding (5% of the animal's live weight). For the decantation method, the animals were sacrificed 36 h after force-feeding and feces were collected directly from the large intestine. For the sedimentation method, feces were collected when they appeared in the tubes attached to the front end of the cylindric tanks. No significant difference (P>0.05) in the apparent digestibility coefficients of crude protein for dietary was observed between the methods tested (74.0% and 76.4% for the dissection and decantation methods, respectively). In conclusion, both methods can be used for the determination of protein digestibility of bullfrog feeds

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Ruibal, Mariana, and Gabriel Laufer. "Bullfrog Lithobates catesbeianus (Amphibia: Ranidae) tadpole diet: description and analysis for three invasive populations in Uruguay." Amphibia-Reptilia 33, no. 3-4 (2012): 355–63. http://dx.doi.org/10.1163/15685381-00002838.

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The North American bullfrog, Lithobates catesbeianus is a dangerous invasive species that has been introduced worldwide for commercial and ornamental purposes. Although studies of the bullfrog’s effects on invaded communities have been carried out, they have focused mostly on post-metamorphic stages. However, considering the experimental evidence and its ecological attributes, the L. catesbeianus tadpole could also have significant impact on invaded communities. The aim of this study was to perform a detailed qualitative and quantitative exploration of the L. catesbeianus larval diet. Gut content was studied and compared for three invaded locations in Uruguay (Departments of Canelones, Soriano and Cerro Largo). Although microscopic algae (Spirogyra spp., Euglena spp., Closterium spp., Volvox spp. and Scenedesmus spp.) were the most frequent prey, the diet was also made up of small invertebrates (especially rotifers) and eggs. Statistically significant differences in diet richness and prey identity were found among the three study sites, probably due to local conditions. One common feature among the three locations was the ingestion of prey with high protein levels, filamentous algae and animal prey. The high frequency of high-protein prey could explain the substantial growth rate of these larvae. Native tadpoles appear to have a much poorer diet than bullfrogs. We can thus assume that the L. catesbeianus larvae will be a major competitor and a potential predator for native communities. We propose that L. catesbeianus tadpoles may have significant effects on invaded communities, and should be considered in future research and managements plans.

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Toews, D. P., and D. F. Stiffler. "Compensation of progressive hypercapnia in the toad (Bufo marinus) and the bullfrog (Rana catesbeiana)." Journal of Experimental Biology 148, no. 1 (January 1, 1990): 293–302. http://dx.doi.org/10.1242/jeb.148.1.293.

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Toads (Bufo marinus L.) and bullfrogs (Rana catesbeiana Shaw) were subjected to a series of 24 h step increases in aerial CO2 (2, 4, 6 and 8%) to assess the degree of extracellular pH compensation at each CO2 level and to ascertain the importance of cutaneous ion transport in this process. Elevation of plasma [HCO3-] occurs during the 24 h period, with the bullfrogs showing a greater ability to compensate at each step. There was no indication that a [HCO3-] threshold of 30 mmol l-1 existed in either species, although bullfrogs appeared to have a greater compensatory potential when exposed to the higher levels of CO2. The results of the ion flux experiments suggest that neither the terrestrial Bufo nor the semi-aquatic Rana use their skin to any great extent for acid-base balance during hypercapnia.

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Carlos, Jaqueline, and Sérgio Luis Pinto da Matta. "Microscopic morphology and testis morphometry of captivity-bred Adult bullfrogs (Lithobates catesbeianus Shaw, 1802)." Brazilian Archives of Biology and Technology 52, no. 6 (December 2009): 1461–72. http://dx.doi.org/10.1590/s1516-89132009000600018.

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The aim of this work was to study the testicular morphometry of captivity-bred adult bullfrogs. Fifteen young adult male were studied, in the rainy season and a lengthy photoperiod. The GSI was established at 0.15%. The nuclear diameter of germinative and Leydig cells, the nucleolus diameter of Sertoli cells and the area of cysts and tubules were determined and the mean number of ISPC, IISPC and SPT per cyst and the mean number of cysts per tubule was estimated. The nucleoplasmatic proportion of the nucleus of the Leydig cell was 76.22%, indicating less cytoplasmic activity. Eight generations of spermatogonia were found. The spermatogenesis efficiency in meiosis and in mitosis was 63 and 49%, respectively. The spermatogenesis of bullfrog fited in the pattern of other captivity Anurans, with differences as the morphology of Sertoli and Leydig cells nuclei.

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Sham, J. S., W. H. Sawyer, and P. K. Pang. "Direct cardiac stimulation by arginine vasotocin in bullfrogs (Rana catesbeiana)." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 256, no. 1 (January 1, 1989): R187—R192. http://dx.doi.org/10.1152/ajpregu.1989.256.1.r187.

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The antidiuretic and vasopressor effects of arginine vasotocin (AVT) in bullfrogs have been well documented. However, the direct cardiac stimulatory effects of AVT have not been previously reported. We found that AVT stimulates significant increases in heart rate, pulse pressure, and the maximal time derivative of ventricular pressure in anesthetized bullfrogs after the beta-adrenergic and muscarinic receptors in the heart were blocked by atropine and propranolol. In spontaneously beating isolated frog atria, AVT increased the beating rate by 20% and the contractile force by 100%. The inotropic effect of AVT was also demonstrated in electrically driven atria and ventricles. Propranolol was ineffective in blocking these cardiac responses in vitro. The Hill coefficients of the concentration-response curves did not differ from unity. In conclusion, AVT possesses both positive chronotropic and inotropic effects in bullfrogs, Rana catesbeiana, probably by direct stimulation of its specific receptors in the heart.

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Yaoi, Yuichi, Masakazu Suzuki, Hideaki Tomura, Yuichi Sasayama, Sakae Kikuyama, and Shigeyasu Tanaka. "Molecular Cloning of Otoconin-22 Complementary Deoxyribonucleic Acid in the Bullfrog Endolymphatic Sac: Effect of Calcitonin on Otoconin-22 Messenger Ribonucleic Acid Levels." Endocrinology 144, no. 8 (August 1, 2003): 3287–96. http://dx.doi.org/10.1210/en.2002-0181.

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Abstract Anuran amphibians have a special organ called the endolymphatic sac (ELS), containing many calcium carbonate crystals, which is believed to have a calcium storage function. The major protein of aragonitic otoconia, otoconin-22, which is considered to be involved in the formation of calcium carbonate crystals, has been purified from the saccule of the Xenopus inner ear. In this study, we cloned a cDNA encoding otoconin-22 from the cDNA library constructed for the paravertebral lime sac (PVLS) of the bullfrog, Rana catesbeiana, and sequenced it. The bullfrog otoconin-22 encoded a protein consisting of 147 amino acids, including a signal peptide of 20 amino acids. The protein had cysteine residues identical in a number and position to those conserved among the secretory phospholipase A2 family. The mRNA of bullfrog otoconin-22 was expressed in the ELS, including the PVLS and inner ear. This study also revealed the presence of calcitonin receptor-like protein in the ELS, with the putative seven-transmembrane domains of the G protein-coupled receptors. The ultimobranchialectomy induced a prominent decrease in the otoconin-22 mRNA levels of the bullfrog PVLS. Supplementation of the ultimobranchialectomized bullfrogs with synthetic salmon calcitonin elicited a significant increase in the mRNA levels of the sac. These findings suggest that calcitonin secreted from the ultimobranchial gland, regulates expression of bullfrog otoconin-22 mRNA via calcitonin receptor-like protein on the ELS, thereby stimulating the formation of calcium carbonate crystals in the lumen of the ELS.

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Sharifian-Fard, Mojdeh, Frank Pasmans, Connie Adriaensen, Sander Devisscher, Tim Adriaens, Gerald Louette, and An Martel. "Ranavirosis in Invasive Bullfrogs, Belgium." Emerging Infectious Diseases 17, no. 12 (December 2011): 2371–72. http://dx.doi.org/10.3201/eid1712.110236.

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Hill, Joseph E., and Pamela G. Parnell. "Adiaspiromycosis in Bullfrogs (Rana Catesbeiana)." Journal of Veterinary Diagnostic Investigation 8, no. 4 (October 1996): 496–97. http://dx.doi.org/10.1177/104063879600800419.

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28

Chowdhury, Vishwajit S., Kazutoshi Yamamoto, Izumi Saeki, Itaru Hasunuma, Taichi Shimura, and Kazuyoshi Tsutsui. "Melatonin Stimulates the Release of Growth Hormone and Prolactin by a Possible Induction of the Expression of Frog Growth Hormone-Releasing Peptide and Its Related Peptide-2 in the Amphibian Hypothalamus." Endocrinology 149, no. 3 (December 6, 2007): 962–70. http://dx.doi.org/10.1210/en.2007-1427.

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We recently identified a novel hypothalamic neuropeptide stimulating GH release in bullfrogs and termed it frog GH-releasing peptide (fGRP). The fGRP precursor encodes fGRP and its related peptides (fGRP-RP-1, -RP-2, and -RP-3), and fGRP-RP-2 also stimulates GH and prolactin (PRL) release. Cell bodies and terminals containing these neuropeptides are localized in the suprachiasmatic nucleus (SCN) and median eminence, respectively. To understand the physiological role of fGRP and fGRP-RP-2, we investigated the mechanisms that regulate the expression of these neuropeptides. This study shows that melatonin induces the expression of fGRP and fGRP-RPs in bullfrogs. Orbital enucleation combined with pinealectomy (Ex plus Px) decreased the expression of fGRP precursor mRNA and content of mature fGRP and fGRP-RPs in the diencephalon including the SCN and median eminence. Conversely, melatonin administration to Ex plus Px bullfrogs increased dose-dependently their expressions. The expression of fGRP precursor mRNA was photoperiodically controlled and increased under short-day photoperiods, when the nocturnal duration of melatonin secretion increases. To clarify the mode of melatonin action on the induction of fGRP and fGRP-RPs, we further demonstrated the expression of Mel1b, a melatonin receptor subtype, in SCN neurons expressing fGRP precursor mRNA. Finally, we investigated circulating GH and PRL levels after melatonin manipulation because fGRP and fGRP-RP-2 stimulate the release of GH and GH/PRL, respectively. Ex plus Px decreased plasma GH and PRL concentrations, whereas melatonin administration increased these hormone levels. These results suggest that melatonin induces the expression of fGRP and fGRP-RP-2, thus stimulating the release of GH and PRL in bullfrogs.

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Saucedo, Bernardo, José M. Serrano, Mónica Jacinto-Maldonado, Rob S. E. W. Leuven, Abraham A. Rocha García, Adriana Méndez Bernal, Andrea Gröne, Steven J. Van Beurden, and César M. Escobedo-Bonilla. "Pathogen Risk Analysis for Wild Amphibian Populations Following the First Report of a Ranavirus Outbreak in Farmed American Bullfrogs (Lithobates catesbeianus) from Northern Mexico." Viruses 11, no. 1 (January 3, 2019): 26. http://dx.doi.org/10.3390/v11010026.

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Ranaviruses are the second deadliest pathogens for amphibian populations throughout the world. Despite their wide distribution in America, these viruses have never been reported in Mexico, the country with the fifth highest amphibian diversity in the world. This paper is the first to address an outbreak of ranavirus in captive American bullfrogs (Lithobates catesbeianus) from Sinaloa, Mexico. The farm experienced high mortality in an undetermined number of juveniles and sub-adult bullfrogs. Affected animals displayed clinical signs and gross lesions such as lethargy, edema, skin ulcers, and hemorrhages consistent with ranavirus infection. The main microscopic lesions included mild renal tubular necrosis and moderate congestion in several organs. Immunohistochemical analyses revealed scant infected hepatocytes and renal tubular epithelial cells. Phylogenetic analysis of five partial ranavirus genes showed that the causative agent clustered within the Frog virus 3 clade. Risk assessment with the Pandora+ protocol demonstrated a high risk for the pathogen to affect amphibians from neighboring regions (overall Pandora risk score: 0.619). Given the risk of American bullfrogs escaping and spreading the disease to wild amphibians, efforts should focus on implementing effective containment strategies and surveillance programs for ranavirus at facilities undertaking intensive farming of amphibians.

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Kinkead, R., W. G. Filmyer, G. S. Mitchell, and W. K. Milsom. "Vagal input enhances responsiveness of respiratory discharge to central changes in pH/CO2 in bullfrogs." Journal of Applied Physiology 77, no. 4 (October 1, 1994): 2048–51. http://dx.doi.org/10.1152/jappl.1994.77.4.2048.

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This study investigated the interaction between vagal afferent input and central chemosensitivity in modulating the respiratory motor output of in vitro brain stem-spinal cord preparations from adult bullfrogs. With this preparation, the spatiotemporal distribution of respiratory-related motor output emulated that of intact bullfrogs; that is, the fictive breathing pattern was mostly episodic. Recordings from cranial motor nerves (V and X) showed that, without peripheral feedback, increasing the PCO2 of the mock cerebrospinal fluid (thereby reducing pH from 8.3 to 7.7) caused a modest increase in respiration-related burst frequency. When the pulmonary branch of a vagus nerve was stimulated phasically (2 V, 20 Hz, 0.2 ms) during each fictive breath to simulate afferent pulmonary stretch receptor feedback 1) the responsiveness of the preparation to the same changes in pH was augmented nearly threefold and 2) the breathing pattern remained episodic. It appears, therefore, that episodic breathing is an intrinsic property of the central nervous system in bullfrogs. It is concluded that there is a strong interaction between vagal feedback and central chemodetection in controlling the temporal relationships that characterize this episodic breathing pattern.

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31

Reid, Christopher. "When the Bullfrogs Are in Love." Grand Street 5, no. 1 (1985): 14. http://dx.doi.org/10.2307/25006790.

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32

Louette, Gerald. "Use of a native predator for the control of an invasive amphibian." Wildlife Research 39, no. 3 (2012): 271. http://dx.doi.org/10.1071/wr11125.

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Context The control of invasive alien species is essential for securing native biodiversity. As for the American bullfrog, Lithobates catesbeianus (Shaw 1802), suspected to cause ecological damage around large parts of the globe, comprehensive management techniques are currently absent. Aims To fill this gap, opportunities arising from biomanipulation of permanent water bodies inhabited by fish were explored. Methods A multi-annual experiment was performed in small and shallow ponds, and effects of complete drawdown (with amphibian and fish removal) and predation (introduction of originally occurring native northern pike, Esox lucius) on non-indigenous bullfrogs were investigated. Key results The presence of pike lead to a strong decline in bullfrog tadpole numbers, whereas no effect of drawdown was observed. Also, communities receiving pike harboured substantially less small and mostly planktivorous fish species (e.g. pumpkinseed, Lepomis gibbosus, and topmouth gudgeon, Pseudorasbora parva). Conclusions The reduction in bullfrog tadpoles may be assigned to both direct and indirect effects induced by pike. First, direct pike predation on tadpoles was observed. Second, as the occurrence of macroinvertebrate-feeding pumpkinseed was low in the presence of pike, the indirect effect of predation by macroinvertebrates on tadpoles may significantly increase, leading to tadpole decline. Implications Biomanipulation of permanent water bodies inhabited by fish can thus be regarded as a candidate for effective and sustainable control of invasive bullfrog. Piscivorous fish introduction may be applied in the specific type of water body, but requires careful consideration of the indigenous status of the introduced species, angling purposes, or specific nature values.

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Yu, Tong Lei, Michael Busam, and David A. Pike. "A tradeoff between mate-quality recognition and species recognition in male Bufo gargarizans that co-occur with Rana catesbeiana." Animal Biology 64, no. 1 (2014): 49–58. http://dx.doi.org/10.1163/15707563-00002429.

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Typically, anuran amphibians favor larger females as mates because larger females lay more eggs; thus, males in amplexus can increase the number of eggs fertilized, and fitness. However, males may also prefer those females that were closest to the norm for their population in overlapping populations, and these individuals do not receive the benefits of enhanced fertilization success. In this study, we test how male Bufo gargarizans choose mates in the presence and absence of an invasive species, bullfrogs (Rana catesbeiana). When given a simultaneous choice between a small male and a large female toad, males discriminated between the sexes and attempted to clasp a large female. However, when one male toad was presented with a large female bullfrog and a small female toad, the males chose both with equal frequency. Therefore, male B. gargarizans appears to trade-off between species and mate-quality recognition, such that those toads co-occurring with heterospecifics do not blindly prefer mate-quality to ensure conspecific matings.

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Wood, Philip G., Olga V. Lopatko, Sandra Orgeig, Jean M. P. Joss, Allan W. Smits, and Christopher B. Daniels. "Control of pulmonary surfactant secretion: an evolutionary perspective." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 278, no. 3 (March 1, 2000): R611—R619. http://dx.doi.org/10.1152/ajpregu.2000.278.3.r611.

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Pulmonary surfactant, a mixture consisting of phospholipids (PL) and proteins, is secreted by type II cells in the lungs of all air-breathing vertebrates. Virtually nothing is known about the factors that control the secretion of pulmonary surfactant in nonmammalian vertebrates. With the use of type II cell cultures from Australian lungfish, North American bullfrogs, and fat-tailed dunnarts, we describe the autonomic regulation of surfactant secretion among the vertebrates. ACh, but not epinephrine (Epi), stimulated total PL and disaturated PL (DSP) secretion from type II cells isolated from Australian lungfish. Both Epi and ACh stimulated PL and DSP secretion from type II cells of bullfrogs and fat-tailed dunnarts. Neither Epi nor ACh affected the secretion of cholesterol from type II cell cultures of bullfrogs or dunnarts. Pulmonary surfactant secretion may be predominantly controlled by the autonomic nervous system in nonmammalian vertebrates. The parasympathetic nervous system may predominate at lower body temperatures, stimulating surfactant secretion without elevating metabolic rate. Adrenergic influences on the surfactant system may have developed subsequent to the radiation of the tetrapods. Furthermore, ventilatory influences on the surfactant system may have arisen at the time of the evolution of the mammalian bronchoalveolar lung. Further studies using other carefully chosen species from each of the vertebrate groups are required to confirm this hypothesis.

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Goldstein, Moise H. "Bob meets bullfrogs: Love at first croak." Journal of the Acoustical Society of America 112, no. 5 (November 2002): 2228. http://dx.doi.org/10.1121/1.4778817.

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Miller, Debra L., Sreekumari Rajeev, Matthew J. Gray, and Charles A. Baldwin. "Frog Virus 3 Infection, Cultured American Bullfrogs." Emerging Infectious Diseases 13, no. 2 (February 2007): 342–43. http://dx.doi.org/10.3201/eid1302.061073.

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Coates, E. L., and G. O. Ballam. "Olfactory receptor response to CO2 in bullfrogs." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 258, no. 5 (May 1, 1990): R1207—R1212. http://dx.doi.org/10.1152/ajpregu.1990.258.5.r1207.

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In vivo electrophysiological recordings of olfactory receptor cells of the bullfrog (Rana catesbeiana) exhibit a receptor response to CO2 concentrations as low as 0.5%. The amplitude of the electroolfactogram (EOG) increased with an increase in the CO2 concentration delivered to the olfactory epithelium. Likewise, there was a significant increase in the decay time (time from 90 to 10% peak EOG amplitude) with an increase in CO2. The EOG rise time (time from 10 to 90% peak EOG amplitude) and the EOG response latency (time from beginning of CO2 pulse to beginning of EOG response) significantly decreased, whereas the plateau time (time from 90% rising phase to 90% falling phase of the peak EOG amplitude) was not significantly altered by an increase in CO2. These results indicate that low concentrations of CO2, below normal end expiratory CO2 concentrations, stimulate olfactory receptor cells. These results support our proposal that the ventilatory depression observed in response to upper airway CO2 in reptiles and amphibians is mediated by CO2-sensitive olfactory receptor cells.

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Alworth, Leanne C., and Victoria M. Vazquez. "A novel system for individually housing bullfrogs." Lab Animal 38, no. 10 (October 2009): 329–33. http://dx.doi.org/10.1038/laban1009-329.

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Tomlinson, Bruce L., Donna E. Tomlinson, and Roy A. Tassava. "Pattern-deficient forelimb regeneration in adult bullfrogs." Journal of Experimental Zoology 236, no. 3 (December 1985): 313–26. http://dx.doi.org/10.1002/jez.1402360309.

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Toloza, E. M., and J. M. Diamond. "Ontogenetic development of nutrient transporters in bullfrog intestine." American Journal of Physiology-Gastrointestinal and Liver Physiology 258, no. 5 (May 1, 1990): G760—G769. http://dx.doi.org/10.1152/ajpgi.1990.258.5.g760.

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The ratio of intestinal glucose (Glc) to amino acid (AA) transporter activity rises with age in animals of species in which the ratio of dietary carbohydrate to protein also rises. Does this shift function to match transporter activity to current dietary substrate levels or to the high AA requirements of young growing animals? We compared intestinal brush-border uptake of Glc and the AA proline (Pro) in adult and tadpole bullfrogs, since with age this species changes from an herbivore to a carnivore and hence its dietary carbohydrate-to-protein ratio decreases rather than increases. Like typical adult herbivores, tadpoles have a long, highly coiled, narrow-bore, thin-walled intestine with a long, heavy colon, whereas adult bullfrogs have a short, wide-bore, thick-walled intestine typical of carnivores. The ratio of Glc to Pro uptake capacity is essentially the same in adults as in larval tadpoles and is typical of carnivores but unprecedently low for herbivores. This suggests that both functions proposed for developmental shifts of Glc and AA transport in other species are significant and that their effects cancel each other in bullfrogs. Transporter kinetic constants vary predictably with developmental stage. Intestinal daily uptake capacity is comparable to actual daily intake for Glc in adults and for Pro in both tadpoles and adults but is much lower than intake for Glc in tadpoles, probably because most carbohydrate ingested by tadpoles is in the form of high molecular weight polymers that are not utilized.

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Eskew, Evan A., Barbara C. Shock, Elise E. B. LaDouceur, Kevin Keel, Michael R. Miller, Janet E. Foley, and Brian D. Todd. "Gene expression differs in susceptible and resistant amphibians exposed to Batrachochytrium dendrobatidis." Royal Society Open Science 5, no. 2 (February 2018): 170910. http://dx.doi.org/10.1098/rsos.170910.

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Chytridiomycosis, the disease caused by the fungal pathogen Batrachochytrium dendrobatidis ( Bd ), has devastated global amphibian biodiversity. Nevertheless, some hosts avoid disease after Bd exposure even as others experience near-complete extirpation. It remains unclear whether the amphibian adaptive immune system plays a role in Bd defence. Here, we describe gene expression in two host species—one susceptible to chytridiomycosis and one resistant—following exposure to two Bd isolates that differ in virulence. Susceptible wood frogs ( Rana sylvatica ) had high infection loads and mortality when exposed to the more virulent Bd isolate but lower infection loads and no fatal disease when exposed to the less virulent isolate. Resistant American bullfrogs ( R. catesbeiana ) had high survival across treatments and rapidly cleared Bd infection or avoided infection entirely. We found widespread upregulation of adaptive immune genes and downregulation of important metabolic and cellular maintenance components in wood frogs after Bd exposure, whereas American bullfrogs showed little gene expression change and no evidence of an adaptive immune response. Wood frog responses suggest that adaptive immune defences may be ineffective against virulent Bd isolates that can cause rapid physiological dysfunction. By contrast, American bullfrogs exhibited robust resistance to Bd that is likely attributable, at least in part, to their continued upkeep of metabolic and skin integrity pathways as well as greater antimicrobial peptide expression compared to wood frogs, regardless of exposure. Greater understanding of these defences will ultimately help conservationists manage chytridiomycosis.

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Robleto, Daniel O., Sheila T. Reitmeyer, and Ceil A. Herman. "Cardiac inotropic effects of leukotriene C4 and prostaglandin I2 in the unanesthetized American bullfrog, Rana catesbeiana." Canadian Journal of Physiology and Pharmacology 66, no. 2 (February 1, 1988): 233–38. http://dx.doi.org/10.1139/y88-039.

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The cardiovascular effects of leukotriene (LT) C4 and prostaglandin (PG) I2 were compared in the unanesthetized American bullfrog, Rana catesbeiana. Bullfrogs were instrumented to measure mean arterial pressure, peak ventricular pressure, its derivative (VP + dP/dt), and heart rate. Two hours after recovery from anesthesia, intravenous injections of LTC4 or PGI2 were tested over a dose range from 0.003 to 3 μg/kg body weight (bw). Both eicosanoids decreased mean arterial pressure, systolic ventricular pressure, and its derivative (VP + dP/dt). The effects of LTC4 and PGI2 on all parameters were similar at doses below 3 μg/kg bw. However, at 3 μg/kg bw, LTC4 had more potent negative inotropic effects than PGI2. Both compounds increased heart rate at 0.3 μg/kg bw, but at 3 μg/kg bw PGI2 caused greater increases than LTC4. The hypotensive and negative inotropic effects of LTC4 were blunted in animals pretreated with indomethacin (4 mg/kg bw) to prevent endogenous prostaglandin and thromboxane synthesis, whereas the cardiovascular effects of PGI2 were unaffected by the blockade. The data show that both eicosanoids have similar qualitative effects on blood pressure and cardiac performance. However, the effects of LTC4 may be partially mediated by release of endogenous cyclooxygenase products, possibly PGI2. These results suggest that the bullfrog, an animal with no coronary arteries, is a useful model for comparative studies of cardiac actions of eicosanoids which are independent of effects mediated by changes in coronary vascular resistance.

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Mauel, Michael J., Debra L. Miller, Kendall S. Frazier, and Murray E. Hines. "Bacterial Pathogens Isolated from Cultured Bullfrogs (Rana Castesbeiana)." Journal of Veterinary Diagnostic Investigation 14, no. 5 (September 2002): 431–33. http://dx.doi.org/10.1177/104063870201400515.

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A commercial bullfrog ( Rana castesbeiana) operation in south Georgia had multiple epizootics of systemic bacterial infections over a 3-year period, 1998–2000. A number of potential pathogens ( Aeromonas hydrophila, Chryseobacterium ( Flavobacterium) meningosepticum, Chryseobacterium ( Flavobacterium) indolgenes, Edwardsiella tarda, Citrobacter freundii, Pseudomonas spp., and ( Streptococcus iniae) were isolated from various tissues. Clinically, frogs demonstrated acute onset of torticolis, stupor, and indifference to stimuli. Cutaneous hyperemia, subcutaneous and muscular hemorrhage, and peripheral edema were consistent gross findings. Histologically, clusters of lymphocytes, monocytes, and occasional acidophiles with scattered granulomas occurred in liver, kidney, and spleen. This is the first report of S. inae and C. meningosepticum as potential disease agents in R. castesbeiana. These findings suggest that a variety of bacteria may be associated with redleg and that culture results must be obtained for accurate diagnosis.

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Sepulveda, Adam, Megan Layhee, Dave Stagliano, Jake Chaffin, Allison Begley, and Bryce Maxell. "Invasion of American bullfrogs along the Yellowstone River." Aquatic Invasions 10, no. 1 (January 2015): 69–77. http://dx.doi.org/10.3391/ai.2015.10.1.07.

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Akasu, Takashi. "Adrenaline depolarization in paravertebral sympathetic neurones of bullfrogs." Pfl�gers Archiv European Journal of Physiology 411, no. 1 (January 1988): 80–87. http://dx.doi.org/10.1007/bf00581650.

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Kerns, Kenneth C., and Eugenia S. Farrar. "Streptozotocin treated bullfrogs fail to develop insulin deficiency." Comparative Biochemistry and Physiology Part A: Physiology 85, no. 4 (January 1986): 765–69. http://dx.doi.org/10.1016/0300-9629(86)90292-6.

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Kinkead, R., M. B. Harris, and W. K. Milsom. "The role of the nucleus isthmi in respiratory pattern formation in bullfrogs." Journal of Experimental Biology 200, no. 12 (June 1, 1997): 1781–93. http://dx.doi.org/10.1242/jeb.200.12.1781.

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The nucleus isthmi (NI) is a mesencephalic structure of the amphibian brain located between the roof of the midbrain and the cerebellum. From a neuroanatomical perspective, the NI can be compared with the pons which, in mammals, contributes to the control of breathing pattern. This study tested the hypothesis that the NI plays a critical role in breathing pattern formation in the bullfrog. More specifically, we postulated that this nucleus was the site responsible for clustering breaths into distinct episodes of breathing. This hypothesis was tested by comparing the respiratory motor output of decerebrate, paralyzed and artificially ventilated bullfrogs before and after bilateral lesions of the NI by pressure microinjections of lidocaine or kainic acid (KA) into this area. Bilateral microinjections of lidocaine or KA into the NI transformed the breathing pattern from episodic (many breaths per episode) to one of evenly spaced single breaths, without affecting the amplitude of the fictive breaths. These changes in breathing pattern were associated with an overall decrease in breathing frequency and a reduction in CO2-chemosensitivity. Breathing episodes of more than one breath reappeared during hypercarbia (3.5% CO2 in air) after KA lesioning. Bilateral lesions to the NI did not affect the changes in the timing or the amplitude of the respiratory-related bursts elicited by pulmonary stretch receptor feedback, indicating that mechanoreflexes do not require NI input. We conclude that the NI is not responsible for the genesis of breathing episodes, but provides a tonic excitatory input to respiratory centers in the lower brainstem. The NI also plays an important role in either CO2 chemodetection or, more probably, integration of CO2 chemoreceptor information. This, in turn, contributes to the production of episodes of more than one breath.

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Boily, Monique H., Virginie E. Bérubé, Philip A. Spear, Christian DeBlois, and Nathalie Dassylva. "HEPATIC RETINOIDS OF BULLFROGS IN RELATION TO AGRICULTURAL PESTICIDES." Environmental Toxicology and Chemistry 24, no. 5 (2005): 1099. http://dx.doi.org/10.1897/04-126r.1.

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49

Simmons, Andrea M., Mary E. Bates, and Jeffrey Knowles. "Non-random patterns of acoustic interactions in chorusing bullfrogs." Journal of the Acoustical Society of America 126, no. 4 (2009): 2270. http://dx.doi.org/10.1121/1.3249293.

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50

Maslow, Joel N., Roberta Wallace, Margaret Michaels, Holly Foskett, Elizabeth A. Maslow, and Julia A. Kiehlbauch. "Outbreak ofMycobacterium marinum infection among captive snakes and bullfrogs." Zoo Biology 21, no. 3 (2002): 233–41. http://dx.doi.org/10.1002/zoo.10022.

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Journal articles on the topic 'Bullfrogs'

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