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Salla RF, Oliveira FN, Jacintho JC, Cirqueira F, Tsukada E, Vieira LG, Rocha TL. Microplastics and TiO 2 nanoparticles mixture as an emerging threat to amphibians: A case study on bullfrog embryos. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 346:123624. [PMID: 38387544 DOI: 10.1016/j.envpol.2024.123624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 01/06/2024] [Accepted: 02/19/2024] [Indexed: 02/24/2024]
Abstract
Emerging contaminants can act as contributing factors to the decline of amphibian populations worldwide. Recently, scientists have drawn attention to the potential ecotoxicity of microplastics and nanomaterials in amphibians, however, their possible effects on embryonic developmental stages are still absent. Thus, the present study analyzed the developmental toxicity of environmentally relevant concentrations of polyethylene microplastics (PE MPs; 60 mg/L) and titanium dioxide nanoparticles (TiO2 NPs; 10 μg/L), isolated or in combination (Mix group) on bullfrog embryos, Aquarana catesbeiana, adapting the Frog Embryo Teratogenesis Assay (FETAX, 96h). Allied to the FETAX protocol, we also analyzed the heart rate and morphometric data. The exposure reduced the survival and hatching rates in groups exposed to TiO2 NPs, and to a lesser extent, also affected the Mix group. TiO2 NPs possibly interacted with the hatching enzymes of the embryos, preventing hatching, and reducing their survival. The reduced effects in the Mix group are due to the agglomeration of both toxicants, making the NPs less available for the embryos. PE MPs got attached to the gelatinous capsule of the chorion (confirmed by fluorescence microscopy), which protected the embryos from eventual direct effects of the microplastics on the hatching and survival rates. Although there were no cardiotoxic effects nor morphometric alterations, there was a significant increase in abdominal edemas in the hatched embryos of the PE MPs group, which indicates that osmoregulation might have been affected by the attachment of the microplastics on the embryos' gelatinous capsule. This study presents the first evidence of developmental toxicity of environmental mixtures of microplastics and nanoparticles on amphibians and reinforces the need for more studies with other amphibian species, especially neotropical specimens that could present bigger sensibility. Our study also highlighted several features of the FETAX protocol as useful tools to evaluate the embryotoxicity of several pollutants on amphibians.
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Affiliation(s)
- Raquel Fernanda Salla
- Laboratory of Environmental Biotechnology and Ecotoxicology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Brazil; Post-graduation Program of Biotechnology and Environmental Monitoring, Federal University of São Carlos (UFSCar), Campus Sorocaba, Sorocaba, São Paulo, Brazil
| | - Fagner Neves Oliveira
- Laboratory of Environmental Biotechnology and Ecotoxicology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Brazil; Laboratory for Research in Morphology and Ontogeny, Institute for Biological Sciences, Federal University of Goiás, Goiânia, Goiás, Brazil
| | - Jaqueline C Jacintho
- Laboratory of Environmental Biotechnology and Ecotoxicology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Brazil
| | - Felipe Cirqueira
- Laboratory of Environmental Biotechnology and Ecotoxicology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Brazil
| | - Elisabete Tsukada
- Post-graduation Program of Biotechnology and Environmental Monitoring, Federal University of São Carlos (UFSCar), Campus Sorocaba, Sorocaba, São Paulo, Brazil
| | - Lucélia Gonçalves Vieira
- Laboratory for Research in Morphology and Ontogeny, Institute for Biological Sciences, Federal University of Goiás, Goiânia, Goiás, Brazil
| | - Thiago Lopes Rocha
- Laboratory of Environmental Biotechnology and Ecotoxicology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Brazil.
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2
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Salica MJ, Goldberg J, Akmentins MS, Candioti FV. Exceptional features of the embryonic ontogeny of a direct‐developing Robber frog. J Zool (1987) 2023. [DOI: 10.1111/jzo.13060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Affiliation(s)
- M. J. Salica
- Instituto de Ecorregiones Andinas (Consejo Nacional de Investigaciones Científicas y Técnicas – Universidad Nacional de Jujuy) San Salvador de Jujuy Argentina
| | - J. Goldberg
- Instituto de Diversidad y Ecología Animal (Consejo Nacional de Investigaciones Científicas y Técnicas – Universidad Nacional de Córdoba); Facultad de Ciencias Exactas, Físicas y Naturales (Universidad Nacional de Córdoba) Córdoba Argentina
| | - M. S. Akmentins
- Instituto de Ecorregiones Andinas (Consejo Nacional de Investigaciones Científicas y Técnicas – Universidad Nacional de Jujuy) San Salvador de Jujuy Argentina
| | - F. Vera Candioti
- Unidad Ejecutora Lillo (Consejo Nacional de Investigaciones Científicas y Técnicas – Fundación Miguel Lillo) San Miguel de Tucumán Argentina
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3
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Colaço G, da Silva HR. Finding a pathway through the rocks: the role of development on the evolution of quasi-terrestriality and the origin of endotrophism in cycloramphids (Anura). Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Anurans have served as models in evolutionary studies on reproduction and development. Several generalizations have emerged but it is unclear whether they represent the diversity of the entire group. We studied the development of two species of the Neotropical family Cycloramphidae. Frogs in this family have peculiar spawning sites and developmental biologies. Whereas some cycloramphid tadpoles are exotrophic, quasi-terrestrial and thrive in films of water that flow over rocky outcrops, others are endotrophic, terrestrial and complete their development outside the eggs laid on the forest floor, under logs or in crevices. Cycloramphid tadpoles have aspects of their morphology distinct from those of pond and stream dwellers; they hatch in more advanced stages of development and have typical tadpole structures, either in a modified form or absent. Herein we present a study of the tadpoles of C. lithomimeticus and T. miliaris, in order to document and discuss alterations in the ontogeny of several larval structures. These changes seem to be associated with adaptations to life in the peculiar habitats where the tadpoles thrive. We infer that the observations we present are explained by development being associated with aspects of terrestrialization and endotrophism.
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Affiliation(s)
- Gustavo Colaço
- Departamento de Biologia Animal, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro , Seropédica, RJ , Brazil
| | - Helio Ricardo da Silva
- Departamento de Biologia Animal, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro , Seropédica, RJ , Brazil
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4
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OUP accepted manuscript. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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5
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Grosso J, Baldo D, Costa CS, Natale GS, Candioti FV. Embryonic ontogeny of three species of Horned Frogs, with a review of early development in Ceratophryidae. J Morphol 2019; 281:17-32. [PMID: 31705582 DOI: 10.1002/jmor.21076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/17/2019] [Accepted: 10/11/2019] [Indexed: 01/06/2023]
Abstract
Horned Frogs of the family Ceratophryidae are conspicuous anurans represented by three endemic South American genera. Most ceratophryids inhabit semiarid environments, but three species of Ceratophrys occupy tropical or temperate humid areas. Several morphological and behavioral characters of larvae and adults are conserved across the family. Based on examination of specimens and accounts in the literature, the embryonic development of C. ornata, C. cranwelli, and the monotypic genus Chacophrys are described and compared with that of species of Lepidobatrachus. Ceratophryid embryos share a suite of morphological features and heterochronic shifts during development. Most features, such as gill structure, ciliation, early hatching, and precocious differentiation of the gut and hind limbs, are shared by all the species regardless the differences in the habitats that occupy. This is consistent with previous observations of some adult characters, and likely supports the hypothesis of an early diversification of ceratophryids in semiarid environments. Other embryonic features, such as the morphology and ontogeny of the oral disc and digestive tract, are correlated with larval feeding habits and vary within the family. The evolutionary and ecological significance of some conserved characters (e.g., gastrulation pattern, Type-A adhesive glands) and other taxon-specific features (e.g., nasal appendix) remain to be explored in the group.
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Affiliation(s)
- Jimena Grosso
- Unidad Ejecutora Lillo (CONICET-FML), San Miguel de Tucumán, Tucumán, Argentina
| | - Diego Baldo
- Instituto de Biología Subtropical (IBS, CONICET-UNaM), Laboratorio de Genética Evolutiva, Facultad de Ciencias Exactas, Universidad Nacional de Misiones, Posadas, Misiones, Argentina
| | - Carolina Salgado Costa
- Centro de Investigaciones del Medioambiente (CIM, UNLP-CONICET), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional La Plata, La Plata, Buenos Aires, Argentina
| | - Guillermo S Natale
- Centro de Investigaciones del Medioambiente (CIM, UNLP-CONICET), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional La Plata, La Plata, Buenos Aires, Argentina
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6
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Grosso J, Baldo D, Cardozo D, Kolenc F, Borteiro C, de Oliveira MIR, Bonino MF, Barrasso DA, Vera Candioti F. Early ontogeny and sequence heterochronies in Leiuperinae frogs (Anura: Leptodactylidae). PLoS One 2019; 14:e0218733. [PMID: 31246982 PMCID: PMC6597095 DOI: 10.1371/journal.pone.0218733] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 06/07/2019] [Indexed: 11/19/2022] Open
Abstract
The study of early development in Neotropical Leiuperinae frogs (Anura, Leptodactylidae) has been addressed by several works in recent times. However, a comparative developmental approach under a phylogenetic context was not available. Herein we analyzed the morphological and ontogenetic diversity of embryos belonging to 22 species of the three largest genera in Leiuperinae. We find that in most cases, variations fit with the phylogeny at the inter- and intrageneric levels. Embryo kyphosis and whitish color are synapomorphies for the clade grouping Physalaemus and Engystomops. The presence of a third lower tooth row on the oral disc is plesiomorphic for Leiuperinae, only changing in derived clades. The configurations and developmental trajectories of the lower lip are exceptionally diverse. The developmental sequences optimized on the phylogenetic tree recover an early differentiated first lower tooth row a synapomorphy of Pseudopaludicola and Physalaemus, and an early differentiated second row as synapomorphy of Pleurodema. On the other hand, few features are highly conserved in the subfamily, such as the adhesive glands universally present in a type-C configuration. Our results also suggest that the morphology and ontogeny of embryos is in some cases associated to the environment where they develop. A large body size, poorly developed transient respiratory structures, large yolk provision and delayed development of the digestive tract occur convergently in embryos inhabiting cold, oxygenated environments. Embryos that develop in warmer water bodies in xeric environments show more complex and persistent transient respiratory structures and an early onset of hind limbs development. Our survey highlights that morphology and early development of anurans can be a valuable source of information for phylogenetic studies, and provide fundamental bases to explore and discuss how evolutionary changes can be shaped by environmental conditions.
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Affiliation(s)
- Jimena Grosso
- Unidad Ejecutora Lillo (CONICET-FML), Tucumán, Argentina
| | - Diego Baldo
- Laboratorio de Genética Evolutiva, (IBS-CONICET), Misiones, Argentina
| | - Darío Cardozo
- Laboratorio de Genética Evolutiva, (IBS-CONICET), Misiones, Argentina
| | - Francisco Kolenc
- Sección Herpetología, Museo Nacional de Historia Natural, Montevideo, Uruguay
| | - Claudio Borteiro
- Sección Herpetología, Museo Nacional de Historia Natural, Montevideo, Uruguay
| | - Marianna I. R. de Oliveira
- Programa de Pós-Graduação em Biodiversidade e Evolução (PPGBioEvo-UFBA), Ondina, Salvador, Bahia, Brazil
| | - Marcelo F. Bonino
- Laboratorio de Ecología, Biología Evolutiva y Comportamiento de Herpetozoos (LEBECH), INIBIOMA (CONICET-UNCo), Rio Negro, Argentina
| | - Diego A. Barrasso
- Instituto de Diversidad y Evolución Austral (IDEAus-CONICET), Chubut, Argentina
- Facultad de Ciencias Naturales y Ciencias de la Salud, Universidad Nacional de la Patagonia “San Juan Bosco” (UNPSJB), Chubut, Argentina
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7
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Cohen KL, Piacentino ML, Warkentin KM. Two types of hatching gland cells facilitate escape-hatching at different developmental stages in red-eyed treefrogs, Agalychnis callidryas (Anura: Phyllomedusidae). Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/bly214] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
| | | | - Karen M Warkentin
- Department of Biology, Boston University, Boston, MA, USA
- Smithsonian Tropical Research Institute, Panamá, República de Panamá
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8
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Ockleford C, Adriaanse P, Berny P, Brock T, Duquesne S, Grilli S, Hernandez-Jerez AF, Bennekou SH, Klein M, Kuhl T, Laskowski R, Machera K, Pelkonen O, Pieper S, Stemmer M, Sundh I, Teodorovic I, Tiktak A, Topping CJ, Wolterink G, Aldrich A, Berg C, Ortiz-Santaliestra M, Weir S, Streissl F, Smith RH. Scientific Opinion on the state of the science on pesticide risk assessment for amphibians and reptiles. EFSA J 2018; 16:e05125. [PMID: 32625798 PMCID: PMC7009658 DOI: 10.2903/j.efsa.2018.5125] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Following a request from EFSA, the Panel on Plant Protection Products and their Residues developed an opinion on the science to support the potential development of a risk assessment scheme of plant protection products for amphibians and reptiles. The coverage of the risk to amphibians and reptiles by current risk assessments for other vertebrate groups was investigated. Available test methods and exposure models were reviewed with regard to their applicability to amphibians and reptiles. Proposals were made for specific protection goals aiming to protect important ecosystem services and taking into consideration the regulatory framework and existing protection goals for other vertebrates. Uncertainties, knowledge gaps and research needs were highlighted.
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9
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Cohen KL, Piacentino ML, Warkentin KM. The hatching process and mechanisms of adaptive hatching acceleration in hourglass treefrogs, Dendropsophus ebraccatus. Comp Biochem Physiol A Mol Integr Physiol 2017; 217:63-74. [PMID: 29056480 DOI: 10.1016/j.cbpa.2017.10.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 10/16/2017] [Accepted: 10/17/2017] [Indexed: 01/25/2023]
Abstract
Environmentally cued hatching is well documented in anurans, enabling embryos to escape diverse threats. However, knowledge of anuran hatching mechanisms is limited and based largely on aquatic-breeding species without known plasticity in hatching timing. Generally, hatching gland cells produce a hatching enzyme that degrades the vitelline membrane. We investigated hatching and its regulation in terrestrial embryos of hourglass treefrogs, Dendropsophus ebraccatus, which accelerate hatching to escape dehydration. We specifically tested if changes in hatching gland cell development or hatching enzyme gene expression are associated with accelerated hatching. We measured perivitelline chamber size of well-hydrated eggs over development as an indicator of breakdown of the vitelline membrane and found that the size of the perivitelline chamber increased steadily until hatching, suggesting gradual hatching enzyme release and vitelline membrane degradation. Hatching gland cells peaked in abundance and began regression substantially prior to hatching, but we found no developmental differences in the abundance or surface area of hatching gland cells between dry and well-hydrated embryos. Hatching enzyme gene expression also peaked early in development then declined, with no difference between hydration treatments. In D. ebraccatus breakdown of the vitelline membrane appears gradual, mediated by hatching enzyme release starting long before hatching. However, hatching acceleration is not associated with ontogenetic changes in hatching gland cell development or hatching enzyme gene expression. This hatching process contrasts with that of red-eyed treefrogs, Agalychnis callidryas, which appear to release enzyme acutely at hatching, yet both species are capable of hatching to escape acute threats.
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Affiliation(s)
- Kristina L Cohen
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA.
| | - Michael L Piacentino
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA; Program in Molecular Biology, Cell Biology and Biochemistry, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA
| | - Karen M Warkentin
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA; Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panamá, República de Panamá
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10
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11
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The Adhesive Glands during Embryogenesis in Some Species of Phyllomedusinae (Anura: Hylidae). J HERPETOL 2017. [DOI: 10.1670/15-127] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Grosso JR, Baldo D, Vera Candioti F. Heterochronic changes during embryonic development of neotropical foam nesting frogs (genus Leptodactylus). ZOOL ANZ 2017. [DOI: 10.1016/j.jcz.2016.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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13
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Candioti FV, Grosso J, Haad B, Pereyra MO, Bornschein MR, Borteiro C, Costa P, Kolenc F, Pie MR, Proaño B, Ron S, Stanescu F, Baldo D. Structural and Heterochronic Variations During the Early Ontogeny in Toads (Anura: Bufonidae). HERPETOLOGICAL MONOGRAPHS 2016. [DOI: 10.1655/herpmonographs-d-16-00004.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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14
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Cohen KL, Seid MA, Warkentin KM. How embryos escape from danger: the mechanism of rapid, plastic hatching in red-eyed treefrogs. J Exp Biol 2016; 219:1875-83. [DOI: 10.1242/jeb.139519] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/30/2016] [Indexed: 02/05/2023]
Abstract
ABSTRACT
Environmentally cued hatching allows embryos to escape dangers and exploit new opportunities. Such adaptive responses require a flexibly regulated hatching mechanism sufficiently fast to meet relevant challenges. Anurans show widespread, diverse cued hatching responses, but their described hatching mechanisms are slow, and regulation of timing is unknown. Arboreal embryos of red-eyed treefrogs, Agalychnis callidryas, escape from snake attacks and other threats by very rapid premature hatching. We used videography, manipulation of hatching embryos and electron microscopy to investigate their hatching mechanism. High-speed video revealed three stages of the hatching process: pre-rupture shaking and gaping, vitelline membrane rupture near the snout, and muscular thrashing to exit through the hole. Hatching took 6.5–49 s. We hypothesized membrane rupture to be enzymatic, with hatching enzyme released from the snout during shaking. To test this, we displaced hatching embryos to move their snout from its location during shaking. The membrane ruptured at the original snout position and embryos became trapped in collapsed capsules; they either moved repeatedly to relocate the hole or shook again and made a second hole to exit. Electron microscopy revealed that hatching glands are densely concentrated on the snout and absent elsewhere. They are full of vesicles in embryos and release most of their contents rapidly at hatching. Agalychnis callidryas' hatching mechanism contrasts with the slow process described in anurans to date and exemplifies one way in which embryos can achieve rapid, flexibly timed hatching to escape from acute threats. Other amphibians with cued hatching may also have novel hatching mechanisms.
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Affiliation(s)
- Kristina L. Cohen
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
| | - Marc A. Seid
- Department of Biology-Neuroscience Program, University of Scranton, 800 Linden Street LSC274, Scranton, PA 18510, USA
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panamá, República de Panamá
| | - Karen M. Warkentin
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panamá, República de Panamá
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15
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Heyer WR, Heyer MM. Systematics, distribution, and bibliography of the frogLeptodactylus insularumBarbour, 1906 (Amphibia: Leptodactylidae). P BIOL SOC WASH 2013. [DOI: 10.2988/0006-324x-126.3.204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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16
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Nokhbatolfoghahai M, Downie JR, Atherton L. External gill motility and striated muscle presence in the embryos of anuran amphibians. Tissue Cell 2012; 45:61-7. [PMID: 23116755 DOI: 10.1016/j.tice.2012.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 09/18/2012] [Accepted: 09/23/2012] [Indexed: 10/27/2022]
Abstract
Anuran external gills were assessed for motility and striated muscle content in 16 species from seven families. Motility of three kinds was observed. Pulsatory movements related to heart beat rhythm were common. In embryos developing to a late stage before hatching, movements of the whole embryo were frequent, with gills rearranging as a consequence. The only clearly active movement, presumably muscle driven, was 'gill flicking', a posterior movement of the entire gill into the body either on one side only, or both together, followed by a return to the normal spread-out position. Some species may actively spread their gills when hanging from the water surface film, but we did not observe this. In some species, active gill movement developed over time, but we were not able to follow all species over such a developmental sequence. The relationship between active motility and muscle content was good in most cases. Observations on late stage embryos of the aromobatid Mannophryne trinitatis are presented for the first time. In one species, we noted spread external gills being used to adhere hatchlings to a surface.
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17
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Heyer WR, Heyer MM. Systematics, distribution, and bibliography of the frogLeptodactylus validusGarman, 1888 (Amphibia: Leptodactylidae). P BIOL SOC WASH 2012. [DOI: 10.2988/12-04.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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18
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Cleveland MH, Sawyer JM, Afelik S, Jensen J, Leach SD. Exocrine ontogenies: on the development of pancreatic acinar, ductal and centroacinar cells. Semin Cell Dev Biol 2012; 23:711-9. [PMID: 22743232 DOI: 10.1016/j.semcdb.2012.06.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 06/13/2012] [Indexed: 02/07/2023]
Abstract
This review summarizes our current understanding of exocrine pancreas development, including the formation of acinar, ductal and centroacinar cells. We discuss the transcription factors associated with various stages of exocrine differentiation, from multipotent progenitor cells to fully differentiated acinar and ductal cells. Within the branching epithelial tree of the embryonic pancreas, this involves the progressive restriction of multipotent pancreatic progenitor cells to either a central "trunk" domain giving rise to the islet and ductal lineages, or a peripheral "tip" domain giving rise to acinar cells. This review also discusses the soluble morphogens and other signaling pathways that influence these events. Finally, we examine centroacinar cells as an enigmatic pancreatic cell type whose lineage remains uncertain, and whose possible progenitor capacities continue to be explored.
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Affiliation(s)
- Megan H Cleveland
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, MD 21205, United States
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19
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Warkentin KM. Plasticity of hatching in amphibians: evolution, trade-offs, cues and mechanisms. Integr Comp Biol 2011; 51:111-27. [PMID: 21642239 DOI: 10.1093/icb/icr046] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Many species of frogs and salamanders, in at least 12 families, alter their timing of hatching in response to conditions affecting mortality of eggs or larvae. Some terrestrially laid or stranded embryos wait to hatch until they are submerged in water. Some embryos laid above water accelerate hatching if the eggs are dehydrating; others hatch early if flooded. Embryos can hatch early in response to predators and pathogens of eggs or delay hatching in response to predators of larvae; some species do both. The phylogenetic pattern of environmentally cued hatching suggests that similar responses have evolved convergently in multiple amphibian lineages. The use of similar cues, including hypoxia and physical disturbance, in multiple contexts suggests potential shared mechanisms underlying the capacity of embryos to respond to environmental conditions. Shifts in the timing of hatching often have clear benefits, but we know less about the trade-offs that favor plasticity, the mechanisms that enable it, and its evolutionary history. Some potentially important types of cued hatching, such as those involving embryo-parent interactions, are relatively unexplored. I discuss promising directions for research and the opportunities that the hatching of amphibians offers for integrative studies of the mechanisms, ecology and evolution of a critical transition between life-history stages.
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Nokhbatolfoghahai M, Downie J. The external gills of anuran amphibians: Comparative morphology and ultrastructure. J Morphol 2008; 269:1197-213. [DOI: 10.1002/jmor.10655] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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