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Richard Shine - One of the best experts on this subject based on the ideXlab platform.
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the accelerating anuran evolution of locomotor performance in cane toads Rhinella marina bufonidae at an invasion front
Proceedings of The Royal Society B: Biological Sciences, 2020Co-Authors: Cameron M Hudson, Richard Shine, Marta Vidalgarcia, Trevor MurrayAbstract:As is common in biological invasions, the rate at which cane toads (Rhinella marina) have spread across tropical Australia has accelerated through time. Individuals at the invasion front travel fur...
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apparent lack of spill over of parasites from an invasive anuran pcr detects entamoeba in cane toads Rhinella marina but not in sympatric australian native frogs
International journal for parasitology. Parasites and wildlife, 2020Co-Authors: Phoebe Rivory, Richard Shine, Gregory P Brown, Cathy Shilton, Jan SlapetaAbstract:Abstract The recent detection of a novel amoebozoan parasite (Entamoeba sp. CT1) killing invasive cane toads (Rhinella marina) in tropical Australia raises concerns of potential spill-over into native anuran populations. Considering the vulnerability of anuran communities globally, Entamoeba sp. CT1 may pose a serious threat to anuran biodiversity. Through PCR-based detection and molecular identification, we investigated the prevalence of Entamoeba spp. in the faeces and colon tissue of cane toads (Rhinella marina) and eleven native Australian frog species from a single locality in the Northern Territory. No Entamoeba DNA was detected in samples of native frog faeces (N = 57) or colons (N = 17). Entamoeba DNA was detected in 24% of 45 cane toads (95%CI 14.08–38.82). Both E. ranarum and Entamoeba sp. CT1 were present in cane toads. The failure of faecal samples to indicate Entamoeba spp. in infected cane toads may be due to cysts in faeces being shed intermittently, degraded before analysis, or impervious to lysis prior to DNA isolation. Our results suggest that native frogs do not carry the pathogen in an area where 20–30% of cane toads are infected with Entamoeba sp. CT1. We demonstrate the importance of recognising PCR inhibition prior to molecular diagnostics, and the apparent inadequacy of faecal samples for the detection of Entamoeba spp. in anurans.
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encounters between freshwater crocodiles and invasive cane toads in north western australia does context determine impact
The Australian zoologist, 2020Co-Authors: Gregory S Clarke, Richard Shine, Cameron M HudsonAbstract:ABSTRACT The potent defensive chemicals of cane toads (Rhinella marina) protect them against predators that lack coevolved physiological tolerance to those toxins. That relative invulnerability may...
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the loneliness of the long distance toad invasion history and social attraction in cane toads Rhinella marina
Biology Letters, 2017Co-Authors: Jodie Gruber, Martin J Whiting, Gregory P Brown, Richard ShineAbstract:Individuals at the leading edge of a biological invasion constantly encounter novel environments. These pioneers may benefit from increased social attraction, because low population densities reduce competition and risks of pathogen transfer, and increase benefits of information transfer. In standardized trials, cane toads (Rhinella marina) from invasion-front populations approached conspecifics more often, and spent more time close to them, than did conspecifics from high-density, long-colonized populations.
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Geographic divergence in dispersal-related behaviour in cane toads from range-front versus range-core populations in Australia
Behavioral Ecology and Sociobiology, 2017Co-Authors: Jodie Gruber, Martin J Whiting, Gregory Brown, Richard ShineAbstract:In invasive species, geographically variable evolutionary and ecological pressures can cause the rapid evolution of divergent behavioural phenotypes. Studies on invasive cane toads ( Rhinella marina ) in tropical Australia have revealed strong (and heritable) shifts in physiological traits related to dispersal rate. Behavioural phenotypes may have evolved in similar ways. We used standardised arena trials to test field-collected adult female toads from three populations: a range-core area in Queensland (ca. 76 years post-colonisation), a range-front population in Western Australia (
Guillermo Schmedahirschmann - One of the best experts on this subject based on the ideXlab platform.
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cytotoxicity and antimitotic activity of Rhinella schneideri and Rhinella marina venoms
Journal of Ethnopharmacology, 2019Co-Authors: Sara Abdelfatah, Guillermo Schmedahirschmann, Thomas EfferthAbstract:Abstract Ethnopharmacological relevance Rhinella schneideri and Rhinella marina are toad venoms distributed in different parts of the world, including Brazil, Columbia and amazon. Venoms extracted from different species have many clinical applications such as antimicrobial cardiotonics and treatment of cancer. Aim of the study; In this study, we aim to investigate the effect of venoms extracted from R. schneideri and R. marina on cancer cells and verify possible mechanism of action. Material and method Cytotoxicity analyses was performed using the resazurin reduction assay, where different concentrations of venoms were tested against sensitive CCRF-CEM and P-gp overexpressing ADR/CEM5000 leukemia cells. Programmed cell death was investigated using the flow cytometric annexin V/propidium iodide apoptosis assay. Furthermore, we analyzed flow cytometric cell cycle analyses of CCRF-CEM cells. Effect on tubulin formation was tested using molecular docking and fluorescence microscopy of U2OS-GFP-α-tubulin osteosarcoma cells treated for 24 h with venoms. Results Cytotoxicity assays revealed a strong activity towards wild-type CCRF-CEM cells (IC50 values of 0.202 ± 0.005 μg/ml and 0.18 ± 0.007 μg/ml for R. schneideri and R. marina, respectively) and multidrug-resistant CEM/ADR5000 cells (IC50 0.403 ± 0.084 μg/ml and 0.32 ± 0.077 μg/ml for R. schneideri and R. marina, respectively). The venoms induced apoptosis as major mechanism of cell death. The venoms induced strong G2/M cell arrest in CCRF-CEM cells. We suggested tubulin as a major target for the venoms. In silico molecular docking of the major constituents of the venoms, i.e. bufalin, marinobufagin, telocinbufagin, hellebrigenin, showed strong binding affinities to tubulin. This result was verified in vitro. The venoms dysregulated microtubule arrangement of U2OS cells expressing GFP-labeled tubulin. Toxicity predictions by QSAR methodology highlighted the toxic features of bufadienolides. Conclusion Our study demonstrated the importance of toad venoms as source of cytotoxic compounds that may serve as lead compounds for the development of novel anticancer drugs.
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the paraguayan Rhinella toad venom implications in the traditional medicine and proliferation of breast cancer cells
Journal of Ethnopharmacology, 2017Co-Authors: Guillermo Schmedahirschmann, Celeste Vega Gomez, Antonieta Rojas De Arias, Alberto Burgosedwards, Jorge Alfonso, Miriam Rolon, Francisco Brusquetti, Flavia Netto, Felix A Urra, Cesar CardenasAbstract:Abstract Ethnopharmacological relevance Toads belonging to genus Rhinella are used in Paraguayan traditional medicine to treat cancer and skin infections. Aim of the study The objective of the study was to determine the composition of venoms obtained from three different Paraguayan Rhinella species, to establish the constituents of a preparation sold in the capital city of Paraguay to treat cancer as containing the toad as ingredient, to establish the effect of the most active Rhinella schneideri venom on the cell cycle using human breast cancer cells and to assess the antiprotozoal activity of the venoms. Methods The venom obtained from the toads parotid glands was analyzed by HPLC-MS-MS. The preparation sold in the capital city of Paraguay to treat cancer that is advertised as made using the toad was analyzed by HPLC-MS-MS. The effect of the R. schneideri venom and the preparation was investigated on human breast cancer cells. The antiprotozoal activity was evaluated on Leishmania braziliensis , L . infantum and murine macrophages. Results From the venoms of R. ornata , R. schneideri and R. scitula , some 40 compounds were identified by spectroscopic and spectrometric means. Several minor constituents are reported for the first time. The preparation sold as made from the toad did not contained bufadienolides or compounds that can be associated with the toad but plant compounds, mainly phenolics and flavonoids. The venom showed activity on human breast cancer cells and modified the cell cycle proliferation. The antiprotozoal effect was higher for the R. schneideri venom and can be related to the composition and relative ratio of constituents compared with R. ornata and R. scitula . Conclusions The preparation sold in the capital city of Paraguay as containing the toad venom, used popularly to treat cancer did not contain the toad venom constituents. Consistent with this, this preparation was inactive on proliferation of human breast cancer cells. In contrast, the toad venoms of Rhinella species altered the cell cycle progression, affecting the proliferation of malignant cells. The findings suggest that care should be taken with the providers of the preparation and that the crude drug present a strong activity towards human breast cancer cell lines. The antiprotozoal effect of the R. schneideri venom was moderate while the venom of R. ornata was devoid of activity and that of R. scitula was active at very high concentration.
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antiproliferative activity and new argininyl bufadienolide esters from the cururu toad Rhinella bufo schneideri
Journal of Ethnopharmacology, 2014Co-Authors: Guillermo Schmedahirschmann, Cristina Quispe, Cristina Theoduloz, Paulo T De Sousa, Carlos Adriano ParizottoAbstract:Abstract Ethnopharmacological relevance Toads known as “cururu” (Rhinella schneideri) have been used in the Brazilian Pantanal and Paraguayan Chaco wetlands to treat erysipelas and cancer. The aim of the study was to assess the antiproliferative effect of the venom obtained from Rhinella schneideri and to identify its constituents by spectroscopic and spectrometric methods. Materials and methods The venom was obtained by gentle pressing the parotid glands of the toads. The dry crude drug was analyzed by HPLC–MS–MS and chromatographed on Sephadex LH-20 to obtain purified compounds and fractions for spectroscopic analysis. The venom and fractions were evaluated for antiproliferative activity towards normal human lung fibroblasts (MRC-5) and four human cancer cell lines: gastric epithelial adenocarcinoma (AGS), lung cancer (SK–MES-1), bladder carcinoma (J82) and promyelocytic leukemia (HL-60). Results From the Rhinella schneideri venom, 29 compounds were isolated and/or identified by spectroscopic and spectrometric means. Three known alkaloids and five argininyl diacids were identified in the complex mixture by HPLC–MS–MS. Nine out of fifteen argininyl diacid derivatives of the bufadienolides bufalin, marinobufagin and telocinobufagin are reported for the first time and four argininyl diacids are described for the first time as natural products. The venom and the fractions 9–13 showed a remarkable antiproliferative effect, with IC50 values in the range 0.019–0.022, 0.035–0.040, 0.028–0.064, 0.042–0.056 and 0.044–0.052 µg/mL for MRC-5, AGS, SK-MES-1, J82 and HL-60 cell lines, respectively. Under the same experimental conditions, IC50 values of the reference compound etoposide were 2.296, 0.277, 1.295, 1.884 and 1.059 µg/mL towards MRC-5, AGS, SK-MES-1, J82 and HL-60 cells, respectively. Conclusions The venom showed a strong antiproliferative effect towards human cancer cells and presented a high chemical diversity in its constituents, supporting its use as anticancer agent. These findings encourage further work on the chemistry and bioactivity of South American toad venoms.
Cristina Silvia Pérez Coll - One of the best experts on this subject based on the ideXlab platform.
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toxicity characterization and environmental risk assessment of mancozeb on the south american common toad Rhinella arenarum
Environmental Science and Pollution Research, 2020Co-Authors: Yamila Asparch, Gabriela Verónica Svartz, Cristina Silvia Pérez CollAbstract:Agricultural activity, especially the increasing use of pesticides, is considered one of the main reasons for the decline of amphibian populations. Mancozeb (MCZ) is one of the most used fungicides worldwide, despite its ancient use and toxicity demonstrated in different taxa. However, there is limited information about the effects of MCZ in amphibians, which are keystones of riparian ecosystems. For species conservation purposes, it is essential to identify the most sensitive developmental period(s) of a given species to a xenobiotic. We evaluated the toxicity of a commercial fungicide of mancozeb, (80% active ingredient) on the early development of the common South American toad Rhinella arenarum (Anura, Bufonidae). Embryos from early blastula (S.4) and larvae from complete operculum (S.25) stages were exposed to a wide range of MCZ concentrations during acute, subchronic and chronic exposure (up to 504 h) periods. The toxicity profiles for lethal and sublethal effects were performed. At all exposure times, MCZ was more toxic to embryos, for instance, NOEC 504 h were 0.01 and 0.05 mg MCZ/L for embryos and larvae, respectively. Thus, embryo sensitivity was 5-fold higher than larvae. A Teratogenic Index of 14 indicated the significant teratogenic potential of this fungicide. Among sublethal effects, embryos exhibited a wide range of abnormalities with high incidence. The ecological risk assessment demonstrated that the estimated Risk Quotient value for Rhinella arenarum embryos at chronic exposure was higher than the Level of Concern value, which warns about the potential risk of MCZ for this native species.
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Synergy Between Diazinon and Nonylphenol in Toxicity During the Early Development of the Rhinella arenarum Toad
Water Air & Soil Pollution, 2016Co-Authors: Carolina Mariel Aronzon, Gabriela Verónica Svartz, Cristina Silvia Pérez CollAbstract:Diazinon is an extensively applied organophosphate pesticide, and nonylphenol is one of the major degradation products of nonylphenol polyethoxylates which are commonly used as surfactant in pesticide formulations. Both pollutants are widely distributed and often coexist in agroecosystems, where they might cause toxic effects to wild biota. This study assessed single and joint toxicity of binary mixtures of these organic compounds on the early development of Rhinella arenarum by means of a standardized test. Joint toxicity of diazinon/nonylphenol mixtures were assessed in embryos and larvae exposed to three different proportions at different exposure times. Embryo and larval toxicity was time-dependent, and larvae were significantly more sensitive than embryos to both compounds. For both embryos and larvae, nonylphenol was between 11 and 18 times more toxic than diazinon. Joint toxicity of the chemicals showed a tendency to be significantly higher than the predicted by additivity effects highlighting the threat that diazinon/nonylphenol mixtures represent for Rhinella arenarum populations.
Chariston Andre Dal Belo - One of the best experts on this subject based on the ideXlab platform.
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entomotoxic activity of Rhinella icterica spix 1824 toad skin secretion in nauphoeta cinerea cockroaches an octopamine like modulation
Pesticide Biochemistry and Physiology, 2018Co-Authors: Allan Pinto Leal, Raquel Soares Oliveira, Patricia De Brum Vieira, Ana Paula Perin, Bruna Trindade Borges, Tiago Gomes Dos Santos, Lucia Vinade, Chiara Valsecchi, Chariston Andre Dal BeloAbstract:Abstract Rhinella icterica is a poisonous toad whose toxic secretion has never been studied against entomotoxic potential. Sublethal doses of Rhinella icterica toxic secretion (RITS) were assayed in Nauphoeta cinerea cockroaches, in order to understand the physiological and behavioral parameters, over the insect central and peripheral nervous system. RITS (10 μg/g) injections, induced behavioral impairment as evidenced by a significant decrease (38 ± 14%) in the distance traveled (p
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Presynaptic Activity of an Isolated Fraction from Rhinella schneideri Poison
Tabriz University of Medical Sciences, 2018Co-Authors: Sandro Rostelato-ferreira, Chariston Andre Dal Belo, Pedro Ismael Da Silva, Stephen Hyslop, Léa Rodrigues-simioni, Thomaz Augusto Alves Rocha-e-silvaAbstract:Purpose: Rhinella schneideri is a toad found in many regions of the South America. The poison of the glands has cardiotoxic effect in animals and neuromuscular effects in mice and avian preparation. The purpose of this work was to identify the toxin responsible for the neuromuscular effect in avian and mice neuromuscular preparation. Methods: The methanolic extract from R. schneideri poison was fractioned by reversed phase HPLC. The purity and molecular mass were determined by LC/MS mass spectrometry. Chick biventer cervicis and mouse phrenic-nerve diaphragm were used as neuromuscular preparations to identify the toxin. Results: The purification resulted in 32 fractions, which 4 of them were active in neuromuscular preparation. The toxin of fraction 20 were chosen for better reproducibility of the whole extract activity and its molecular mass was 730.6 Da. The toxin produced facilitation of the muscle contraction followed by a complete neuromuscular blockade in chick biventer cervicis preparation in 90 min without interfering with the exogenous response to ACh and KCl. The quantal content was increased from 128 ± 13 (control) to 216 ± 44 (after 5 min and sustained until 60 min) in the presence of the toxin. Conclusion: In conclusion, our results demonstrated that the neuromuscular action of the poison of Rhinella schneideri is a multitoxin effect. More, the present work first isolated a 730.6 Da toxin that better represent the whole poison neuromuscular effect, to which is attributed a presynaptic action in avian and mouse neuromuscular preparation
Thomas Efferth - One of the best experts on this subject based on the ideXlab platform.
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cytotoxicity and antimitotic activity of Rhinella schneideri and Rhinella marina venoms
Journal of Ethnopharmacology, 2019Co-Authors: Sara Abdelfatah, Guillermo Schmedahirschmann, Thomas EfferthAbstract:Abstract Ethnopharmacological relevance Rhinella schneideri and Rhinella marina are toad venoms distributed in different parts of the world, including Brazil, Columbia and amazon. Venoms extracted from different species have many clinical applications such as antimicrobial cardiotonics and treatment of cancer. Aim of the study; In this study, we aim to investigate the effect of venoms extracted from R. schneideri and R. marina on cancer cells and verify possible mechanism of action. Material and method Cytotoxicity analyses was performed using the resazurin reduction assay, where different concentrations of venoms were tested against sensitive CCRF-CEM and P-gp overexpressing ADR/CEM5000 leukemia cells. Programmed cell death was investigated using the flow cytometric annexin V/propidium iodide apoptosis assay. Furthermore, we analyzed flow cytometric cell cycle analyses of CCRF-CEM cells. Effect on tubulin formation was tested using molecular docking and fluorescence microscopy of U2OS-GFP-α-tubulin osteosarcoma cells treated for 24 h with venoms. Results Cytotoxicity assays revealed a strong activity towards wild-type CCRF-CEM cells (IC50 values of 0.202 ± 0.005 μg/ml and 0.18 ± 0.007 μg/ml for R. schneideri and R. marina, respectively) and multidrug-resistant CEM/ADR5000 cells (IC50 0.403 ± 0.084 μg/ml and 0.32 ± 0.077 μg/ml for R. schneideri and R. marina, respectively). The venoms induced apoptosis as major mechanism of cell death. The venoms induced strong G2/M cell arrest in CCRF-CEM cells. We suggested tubulin as a major target for the venoms. In silico molecular docking of the major constituents of the venoms, i.e. bufalin, marinobufagin, telocinbufagin, hellebrigenin, showed strong binding affinities to tubulin. This result was verified in vitro. The venoms dysregulated microtubule arrangement of U2OS cells expressing GFP-labeled tubulin. Toxicity predictions by QSAR methodology highlighted the toxic features of bufadienolides. Conclusion Our study demonstrated the importance of toad venoms as source of cytotoxic compounds that may serve as lead compounds for the development of novel anticancer drugs.
