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Gerontology 1994Methods of age determination of amphibians by counting annual layers in the bone tissue and data on longevity of amphibians (both anurans and urodeles) in nature are... (Comparative Study)
Comparative Study Review
Methods of age determination of amphibians by counting annual layers in the bone tissue and data on longevity of amphibians (both anurans and urodeles) in nature are presented. Age compositions of amphibian populations are discussed and their variations analysed.
Topics: Age Determination by Skeleton; Aging; Amphibians; Animals; Anura; Body Constitution; Bone and Bones; Female; Longevity; Male; Species Specificity; Urodela
PubMed: 7926852
DOI: 10.1159/000213583 -
The Veterinary Clinics of North... Jan 2020Amphibians are a remarkably diverse group of vertebrates with lifestyles ranging from fully aquatic to entirely terrestrial. Although some aspects of renal anatomy and... (Review)
Review
Amphibians are a remarkably diverse group of vertebrates with lifestyles ranging from fully aquatic to entirely terrestrial. Although some aspects of renal anatomy and physiology are similar among all amphibians, species differences in nitrogenous waste production and broad normal variation in plasma osmolality and composition make definitive antemortem diagnosis of renal disease challenging. Treatment is often empirical and aimed at addressing possible underlying infection, reducing abnormal fluid accumulation, and optimizing husbandry practices to support metabolic and fluid homeostasis. This article reviews amphibian renal anatomy and physiology, provides recommendations for diagnostic and therapeutic options, and discusses etiologies of renal disease.
Topics: Amphibians; Animals; Kidney Diseases; Neoplasms
PubMed: 31759449
DOI: 10.1016/j.cvex.2019.09.005 -
Environmental Pollution (Barking, Essex... Sep 2015The loss of genetic diversity, due to exposure to chemical contamination (genetic erosion), is a major threat to population viability. Genetic erosion is the loss of... (Review)
Review
The loss of genetic diversity, due to exposure to chemical contamination (genetic erosion), is a major threat to population viability. Genetic erosion is the loss of genetic variation: the loss of alleles determining the value of a specific trait or set of traits. Almost a third of the known amphibian species is considered to be endangered and a decrease of genetic variability can push them to the verge of extinction. This review indicates that loss of genetic variation due to chemical contamination has effects on: 1) fitness, 2) environmental plasticity, 3) co-tolerance mechanisms, 4) trade-off mechanisms, and 5) tolerance to pathogens in amphibian populations.
Topics: Amphibians; Animals; Biological Evolution; Environmental Pollution; Genetic Variation
PubMed: 25969378
DOI: 10.1016/j.envpol.2015.04.027 -
Biological Reviews of the Cambridge... Oct 2022Descriptions of amphibian habitat, both aquatic and terrestrial, often include plants as characteristics but seldom is it understood whether and how those plants affect... (Review)
Review
Descriptions of amphibian habitat, both aquatic and terrestrial, often include plants as characteristics but seldom is it understood whether and how those plants affect amphibian ecology. Understanding how plants affect amphibian populations is needed to develop strategies to combat declines of some amphibian populations. Using a systematic approach, we reviewed and synthesized available literature on the effects of plants on pond-breeding amphibians during the aquatic and terrestrial stages of their life cycle. Our review highlights that plant communities can strongly influence the distribution, abundance, and performance of amphibians in multiple direct and indirect ways. We found three broad themes of plants' influence on amphibians: plants can affect amphibians through effects on abiotic conditions including the thermal, hydric, and chemical aspects of an amphibian's environment; plants can have large effects on aquatic life stages through effects on resource quality and abundance; and plants can modify the nature and strength of interspecific interactions between amphibians and other species - notably predators. We synthesized insights gained from the literature to discuss how plant community management fits within efforts to manage amphibian populations and to guide future research efforts. While some topical areas are well researched, we found a general lack of mechanistic and trait-based work which is needed to advance our understanding of the drivers through which plants influence amphibian ecology. Our literature review reveals the substantial role that plants can have on amphibian ecology and the need for integrating plant and amphibian ecology to improve research and management outcomes for amphibians.
Topics: Amphibians; Animals; Ecosystem; Life Cycle Stages; Plant Breeding; Plants
PubMed: 35441800
DOI: 10.1111/brv.12861 -
The Veterinary Clinics of North... Jan 2007Cytology is an inexpensive yet powerful diagnostic tool that allows for rapid diagnosis of many common disease conditions in amphibian patients. Although the emphasis of... (Review)
Review
Cytology is an inexpensive yet powerful diagnostic tool that allows for rapid diagnosis of many common disease conditions in amphibian patients. Although the emphasis of this article is on infectious diseases, there is great potential for application of cytologic diagnosis to variety of medical conditions as the knowledge base in amphibian medicine and pathology continues to grow. Routine methods used that may fall under the umbrella of cytology range from wet mount examination of skin scrapings (or gill biopsies of larvae) to examination of stained impression smears. Routine Romanowsky's-type stains work well for amphibian samples. Preparation of multiple smears is always recommended to allow for use of special staining procedures.
Topics: Amphibians; Animal Diseases; Animals; Body Fluids; Cytodiagnosis; Skin Diseases
PubMed: 17198964
DOI: 10.1016/j.cvex.2006.10.006 -
Uchu Seibutsu Kagaku Dec 2002We review here the scientific significance of the use of amphibians for research in gravitational biology. Since amphibian eggs are quite large, yet develop rapidly and... (Review)
Review
We review here the scientific significance of the use of amphibians for research in gravitational biology. Since amphibian eggs are quite large, yet develop rapidly and externally, it is easy to observe their development. Consequently amphibians were the first vertebrates to have their early developmental processes investigated in space. Though several deviations from normal embryonic development occur when amphibians are raised in microgravity, their developmental program is robust enough to return the organisms to an ostensibly normal morphology by the time they hatch. Evolutionally, amphibians were the first vertebrate animal to come out of the water and onto land. Subsequently they diversified and have adaptively radiated to various habitats. They now inhabit aquatic, terrestrial, arboreal and fossorial niches. This diversity can be used to help study the biological effects of gravity at the organismal level, where macroscopic phenomena are associated with gravitational loading. By choosing different amphibian models and using a comparative approach one can effectively identify the action of gravity on biological systems, and the adaptation that vertebrates have made to this loading. Advances in cellular and molecular biology provide powerful tools for the study in many fields, including gravitational biology, and amphibians have proven to be good models for studies at those levels as well. The low metabolic rates of amphibians make them convenient organisms to work with (compared to birds and mammals) in the difficult and confined spaces on orbiting research platforms. We include here a review of what is known about and the potential for further behavioral and physiological researches in space using amphibians.
Topics: Amphibians; Animals; Anura; Behavior, Animal; Biological Evolution; Biological Science Disciplines; Developmental Biology; Female; Gravitation; Male; Models, Animal; Space Flight; Weightlessness
PubMed: 12721528
DOI: 10.2187/bss.16.245 -
Biochimica Et Biophysica Acta Aug 2009Amphibian species have experienced population declines and extinctions worldwide that are unprecedented in recent history. Many of these recent declines have been linked... (Review)
Review
Amphibian species have experienced population declines and extinctions worldwide that are unprecedented in recent history. Many of these recent declines have been linked to a pathogenic skin fungus, Batrachochytrium dendrobatidis, or to iridoviruses of the genus Ranavirus. One of the first lines of defense against pathogens that enter by way of the skin are antimicrobial peptides synthesized and stored in dermal granular glands and secreted into the mucus following alarm or injury. Here, I review what is known about the capacity of amphibian antimicrobial peptides from diverse amphibians to inhibit B. dendrobatidis or ranavirus infections. When multiple species were compared for the effectiveness of their in vitro antimicrobial peptides defenses against B. dendrobatidis, non-declining species of rainforest amphibians had more effective antimicrobial peptides than species in the same habitat that had recently experienced population declines. Further, there was a significant correlation between the effectiveness of the antimicrobial peptides and resistance of the species to experimental infection. These studies support the hypothesis that antimicrobial peptides are an important component of innate defenses against B. dendrobatidis. Some amphibian antimicrobial peptides inhibit ranavirus infections and infection of human T lymphocytes by the human immunodeficiency virus (HIV). An effective antimicrobial peptide defense against skin pathogens appears to depend on a diverse array of genes expressing antimicrobial peptides. The production of antimicrobial peptides may be regulated by signals from the pathogens. However, this defense must also accommodate potentially beneficial microbes on the skin that compete or inhibit growth of the pathogens. How this delicate balancing act is accomplished is an important area of future research.
Topics: Amino Acid Sequence; Amphibian Proteins; Amphibians; Animals; Antimicrobial Cationic Peptides; Fungi; Molecular Sequence Data; Population Dynamics; Skin
PubMed: 19327341
DOI: 10.1016/j.bbamem.2009.03.008 -
Developmental and Comparative Immunology Mar 2021Until recently, different families of urodele amphibians were thought to express distinct subsets of immunoglobulin (Ig) isotypes. In this study, we explored cDNAs...
Until recently, different families of urodele amphibians were thought to express distinct subsets of immunoglobulin (Ig) isotypes. In this study, we explored cDNAs encoding Ig heavy-chains (H-chains) in three species of urodele amphibians. We found that Cynops pyrrhogaster, Pleurodeles waltl, and Ambystoma mexicanum each carry genes encoding four Ig H-chain isotypes, including IgM, IgY, IgD, and IgX, similar to those found in anuran amphibians. We also found that urodele IgDs have a long constant region similar to those found in anuran, reptiles, and bony fishes. We also found several putative IgD splice variants. Our findings indicated that P. waltl IgP is not a novel isotype but an IgD splice variant. Altogether, our findings indicate that IgD splice variants may be universally expressed among amphibian species.
Topics: Alternative Splicing; Amino Acid Sequence; Amphibian Proteins; Amphibians; Animals; DNA, Complementary; Immunoglobulin D; Immunoglobulin Heavy Chains; Immunoglobulin Isotypes; Phylogeny; Sequence Alignment; Urodela
PubMed: 33301796
DOI: 10.1016/j.dci.2020.103963 -
Nature Communications Oct 2019Parental care is extremely diverse across species, ranging from simple behaviours to complex adaptations, varying in duration and in which sex cares. Surprisingly, we...
Parental care is extremely diverse across species, ranging from simple behaviours to complex adaptations, varying in duration and in which sex cares. Surprisingly, we know little about how such diversity has evolved. Here, using phylogenetic comparative methods and data for over 1300 amphibian species, we show that egg attendance, arguably one of the simplest care behaviours, is gained and lost faster than any other care form, while complex adaptations, like brooding and viviparity, are lost at very low rates, if at all. Prolonged care from the egg to later developmental stages evolves from temporally limited care, but it is as easily lost as it is gained. Finally, biparental care is evolutionarily unstable regardless of whether the parents perform complementary or similar care duties. By considering the full spectrum of parental care adaptations, our study reveals a more complex and nuanced picture of how care evolves, is maintained, or is lost.
Topics: Adaptation, Physiological; Amphibians; Animals; Biodiversity; Biological Evolution; Ecosystem; Female; Male; Maternal Behavior; Paternal Behavior; Reproduction; Species Specificity
PubMed: 31624263
DOI: 10.1038/s41467-019-12608-5 -
Diseases of Aquatic Organisms Dec 2022In the early 2000s, numerous cases of European amphibian population declines and mass die-offs started to emerge. Investigating those events led to the discovery that...
In the early 2000s, numerous cases of European amphibian population declines and mass die-offs started to emerge. Investigating those events led to the discovery that wild European amphibians were confronted with grave disease threats caused by introduced pathogens, namely the amphibian and the salamander chytrid fungi Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal) and ranaviruses. In Greece, Bd was previously documented among wild amphibian populations in 2 different locations and 3 different species. However, no disease-related mass declines or mortality events have been reported. In this work, we build upon previous findings with new, subsequently obtained data, resulting in a 225-sample dataset of 14 species from 17 different locations throughout Greece, in order to examine the occurrence status of all 3 pathogens responsible for emerging infectious diseases in European amphibians. No positive samples for Bsal or ranavirus were recorded in any location. We confirmed the presence of Bd in 4 more localities and in 4 more species, including 1 urodelan (Macedonian crested newt Triturus macedonicus) and 1 introduced anuran (American bullfrog Lithobates catesbeianus). All insular localities were negative for Bd, except for Crete, where Bd was identified in 2 different locations. Again, no mass declines or die-offs were recorded in any Bd-positive area or elsewhere. However, given the persistence of Bd across Greece over the past ~20 yr, monitoring efforts should continue, and ideally be further expanded.
Topics: Animals; Chytridiomycota; Batrachochytrium; Greece; Mycoses; Amphibians; Ranavirus; Communicable Diseases, Emerging; Rana catesbeiana
PubMed: 36519684
DOI: 10.3354/dao03712