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Peptides Feb 2021One of the major families of host defense peptides (HDPs) in vertebrates are β-defensins. They constitute important components of innate immunity and have remained an... (Review)
Review
One of the major families of host defense peptides (HDPs) in vertebrates are β-defensins. They constitute important components of innate immunity and have remained an interesting topic of research for more than two decades. While many β-defensin sequences in mammals and birds have been identified and their properties and functions characterized, β-defensin peptides from other groups of vertebrates, particularly reptiles, are still largely unexplored. In this review, we focus on reptilian β-defensins and summarize different aspects of their biology, such as their genomic organization, evolution, structure, and biological activities. Reptilian β-defensin genes exhibit similar genomic organization to birds and their number and gene structure are variable among different species. During the evolution of reptiles, several gene duplication and deletion events have occurred and the functional diversification of β-defensins has been mainly driven by positive selection. These peptides display broad antimicrobial activity in vitro, but a deeper understanding of their mechanisms of action in vivo, including their role as immunomodulators, is still lacking. Reptilian β-defensins constitute unique polypeptide sequences to expand our current understanding of innate immunity in these animals and elucidate core biological functions of this family of HDPs across amniotes.
Topics: Alligators and Crocodiles; Animals; Evolution, Molecular; Genome; Peptides; Reptiles; beta-Defensins
PubMed: 33309943
DOI: 10.1016/j.peptides.2020.170473 -
Zootaxa Jun 2023North Sweden ('Norrland' in Swedish) covers 243 000 km2 and lies mainly in the boreal biome. The herpetofauna comprises five amphibian and four reptile species:...
North Sweden ('Norrland' in Swedish) covers 243 000 km2 and lies mainly in the boreal biome. The herpetofauna comprises five amphibian and four reptile species: Lissotriton vulgaris, Triturus cristatus, Bufo bufo, Rana temporaria, Rana arvalis, Zootoca vivipara, Anguis fragilis, Natrix natrix, and Vipera berus. Successful conservation and management of amphibians and reptiles depend on accurate information about distribution, habitat affinities, and abundance. Such knowledge is also essential as a benchmark to assess changes in distribution and abundance that may come about as a result of climate change and human habitat alteration. This paper aims to present accurate distribution maps, describe habitat affinities, and provide abundance estimates for the herpetofauna of North Sweden for the period 1970-2022. Distribution data are presented by traditional faunistic provinces, as well as by biotic regions and alpine life zones. Separate sections address post-glacial colonization and a herpetological perspective on anthropogenic changes in relation to species´ present status. Bufo bufo, Rana temporaria, Rana arvalis, Zootoca vivipara, and Vipera berus are widely distributed throughout the boreal sub-regions. Rana temporaria, Zootoca vivipara, and Vipera berus also extend into the alpine region. Triturus cristatus, Anguis fragilis, and Natrix natrix occur mainly in the coastal parts of the Southern Boreal region. There are no signs of recent changes in distribution range, but Lissotriton vulgaris, Triturus cristatus, and Rana arvalis have been largely overlooked in the past and have a much wider occurrence than previously recognized. Most species are found in habitats usually not described in all-European field guides. Nearly all anurans hibernate in water. Abundance estimates suggest that some species are more common in the boreal than thought, supporting the notion that a large share of their total European population occurs there. Although local extinctions and declines are known, there are no signs of widespread population decline for any species during the study period.
Topics: Humans; Animals; Sweden; Amphibians; Reptiles; Ecosystem; Anura; Ranidae; Viperidae; Colubridae; Lizards
PubMed: 37518558
DOI: 10.11646/zootaxa.5301.3.1 -
The Journal of General Virology Apr 2023Despite recent advances in molecular techniques, infection studies remain an important tool for biosecurity, veterinary and conservation medicines. Experimental... (Review)
Review
Despite recent advances in molecular techniques, infection studies remain an important tool for biosecurity, veterinary and conservation medicines. Experimental infection studies are performed for many reasons: to investigate causal links between pathogens and disease, to study host species susceptibility, to study immune response to inoculation, to investigate pathogen transmission and to investigate methods for infection control. Experimental infection studies using viruses in reptiles have been conducted sporadically since at least the 1930s and this continues to be a fertile area of research. This review catalogues previously published research in the field. The key parameters of each study are tabulated, providing a summary of more than 100 experiments linked to their original publications. Common themes and trends within the data are discussed.
Topics: Animals; Reptiles; Virus Diseases; Viruses
PubMed: 37014785
DOI: 10.1099/jgv.0.001832 -
Philosophical Transactions of the Royal... Aug 2023A range of abiotic parameters within a reptile nest influence the viability and attributes (including sex, behaviour and body size) of hatchlings that emerge from that... (Review)
Review
A range of abiotic parameters within a reptile nest influence the viability and attributes (including sex, behaviour and body size) of hatchlings that emerge from that nest. As a result of that sensitivity, a reproducing female can manipulate the phenotypic attributes of her offspring by laying her eggs at times and in places that provide specific conditions. Nesting reptiles shift their behaviour in terms of timing of oviposition, nest location and depth of eggs beneath the soil surface across spatial and temporal gradients. Those maternal manipulations affect mean values and variances of both temperature and soil moisture, and may modify the vulnerability of embryos to threats such as predation and parasitism. By altering thermal and hydric conditions in reptile nests, climate change has the potential to dramatically modify the developmental trajectories and survival rates of embryos, and the phenotypes of hatchlings. Reproducing females buffer such effects by modifying the timing, location and structure of nests in ways that enhance offspring viability. Nonetheless, our understanding of nesting behaviours in response to climate change remains limited in reptiles. Priority topics for future studies include documenting climate-induced changes in the nest environment, the degree to which maternal behavioural shifts can mitigate climate-related deleterious impacts on offspring development, and ecological and evolutionary consequences of maternal nesting responses to climate change. This article is part of the theme issue 'The evolutionary ecology of nests: a cross-taxon approach'.
Topics: Animals; Female; Nesting Behavior; Climate Change; Reptiles; Adaptation, Physiological; Temperature; Soil
PubMed: 37427463
DOI: 10.1098/rstb.2022.0153 -
Integrative and Comparative Biology Dec 2022Reptiles, the only ectothermic amniotes, employ a wide variety of physiological adaptations to adjust to their environments but remain vastly understudied in the field... (Review)
Review
Reptiles, the only ectothermic amniotes, employ a wide variety of physiological adaptations to adjust to their environments but remain vastly understudied in the field of immunology and ecoimmunology in comparison to other vertebrate taxa. To address this knowledge gap, we assessed the current state of research on reptilian innate immunology by conducting an extensive literature search of peer-reviewed articles published across the four orders of Reptilia (Crocodilia, Testudines, Squamata, and Rhynchocephalia). Using our compiled dataset, we investigated common techniques, characterization of immune components, differences in findings and type of research among the four orders, and immune responses to ecological and life-history variables. We found that there are differences in the types of questions asked and approaches used for each of these reptilian orders. The different conceptual frameworks applied to each group has led to a lack of unified understanding of reptilian immunological strategies, which, in turn, have resulted in large conceptual gaps in the field of ecoimmunology as a whole. To apply ecoimmunological concepts and techniques most effectively to reptiles, we must combine traditional immunological studies with ecoimmunological studies to continue to identify, characterize, and describe the reptilian immune components and responses. This review highlights the advances and gaps that remain to help identify targeted and cohesive approaches for future research in reptilian ecoimmunological studies.
Topics: Animals; Reptiles; Lizards; Snakes
PubMed: 35833292
DOI: 10.1093/icb/icac116 -
Parasitology Research Sep 2021Wolbachia, a maternally transmitted Gram-negative endosymbiont of onchocercid nematodes and arthropods, has a role in the biology of their host; thus it has been...
Wolbachia, a maternally transmitted Gram-negative endosymbiont of onchocercid nematodes and arthropods, has a role in the biology of their host; thus it has been exploited for the filariasis treatment in humans. To assess the presence and prevalence of this endosymbiont in reptiles and their ectoparasites, blood and tail tissue as well as ticks and mites collected from them were molecularly screened for Wolbachia DNA using two sets of primers targeting partial 16S rRNA and Wolbachia surface protein (wsp) genes. Positive samples were screened for the partial 12S rRNA and cytochrome c oxidase subunit 1 (cox1) genes for filarioids. Of the different species of lizards (Podarcis siculus, Podarcis muralis and Lacerta bilineata) and snakes (Elaphe quatuorlineata and Boa constrictor constrictor) screened from three collection sites, only P. siculus scored positive for Wolbachia 16S rRNA. Among ectoparasites collected from reptiles (Ixodes ricinus ticks and Neotrombicula autumnalis, Ophionyssus sauracum and Ophionyssus natricis mites), I. ricinus (n = 4; 2.8%; 95% CI, 0.9-7) from P. siculus, N. autumnalis (n = 2 each; 2.8%; 95% CI, 0.9-6.5) from P. siculus and P. muralis and O. natricis (n = 1; 14.3%; 95% CI, 0.7-55.4) from Boa constrictor constrictor scored positive for Wolbachia DNA. None of the positive Wolbachia samples scored positive for filarioids. This represents the first report of Wolbachia in reptilian hosts and their ectoparasites, which follows a single identification in the intestinal cells of a filarioid associated with a gecko. This data could contribute to better understand the reptile filarioid-Wolbachia association and to unveil the evolutionary pattern of Wolbachia in its filarial host.
Topics: Animals; Ixodes; Mites; Phylogeny; RNA, Ribosomal, 16S; Reptiles; Wolbachia
PubMed: 34292377
DOI: 10.1007/s00436-021-07237-1 -
Biological Reviews of the Cambridge... Feb 2022The colonisation of freshwater and marine ecosystems by land vertebrates has repeatedly occurred in amphibians, reptiles, birds and mammals over the course of 300... (Review)
Review
The colonisation of freshwater and marine ecosystems by land vertebrates has repeatedly occurred in amphibians, reptiles, birds and mammals over the course of 300 million years. Functional interpretations of the fossil record are crucial to understanding the forces shaping these evolutionary transitions. Secondarily aquatic tetrapods have acquired a suite of anatomical, physiological and behavioural adaptations to locomotion in water. However, much of this information is lost for extinct clades, with fossil evidence often restricted to osteological data and a few extraordinary specimens with soft tissue preservation. Traditionally, functional morphology in fossil secondarily aquatic tetrapods was investigated through comparative anatomy and correlation with living functional analogues. However, in the last two decades, biomechanics in palaeobiology has experienced a remarkable methodological shift. Anatomy-based approaches are increasingly rigorous, informed by quantitative techniques for analysing shape. Moreover, the incorporation of physics-based methods has enabled objective tests of functional hypotheses, revealing the importance of hydrodynamic forces as drivers of evolutionary innovation and adaptation. Here, we present an overview of the latest research on the locomotion of extinct secondarily aquatic tetrapods, with a focus on amniotes, highlighting the state-of-the-art experimental approaches used in this field. We discuss the suitability of these techniques for exploring different aspects of locomotory adaptation, analysing their advantages and limitations and laying out recommendations for their application, with the aim to inform future experimental strategies. Furthermore, we outline some unexplored research avenues that have been successfully deployed in other areas of palaeobiomechanical research, such as the use of dynamic models in feeding mechanics and terrestrial locomotion, thus providing a new methodological synthesis for the field of locomotory biomechanics in extinct secondarily aquatic vertebrates. Advances in imaging technology and three-dimensional modelling software, new developments in robotics, and increased availability and awareness of numerical methods like computational fluid dynamics make this an exciting time for analysing form and function in ancient vertebrates.
Topics: Animals; Biological Evolution; Ecosystem; Fossils; Locomotion; Mammals; Reptiles
PubMed: 34486794
DOI: 10.1111/brv.12790 -
Journal of Helminthology Jan 2023Reptiles, as well as other vertebrate groups, harbour a significant diversity of parasitic organisms, from nematodes and other helminths to viruses and bacteria. The... (Review)
Review
Reptiles, as well as other vertebrate groups, harbour a significant diversity of parasitic organisms, from nematodes and other helminths to viruses and bacteria. The Northeast is one of the richest regions in Brazil in terms of the reptile diversity, number of species and endemism. Parasites are diverse organisms and knowledge about the parasitic fauna of vertebrates is an important factor in understanding the ecological relationships between hosts and the environment. Studies on the parasitic fauna of reptiles in South America have increased in the past few years. The present review is a compilation of 122 studies published from 1924 to 2021. We present information on 101 species of reptiles from five groups (amphisbaenians, crocodile, testudines, snakes and lizards) and 183 parasitic taxa belonging to four phyla: Nematoda; Arthropoda; Platyhelminthes; and Acanthocephala. Nematodes were the most frequently recorded species. Lizards and snakes had more records of parasitism and higher levels of parasite richness and diversity. Ceará was the state with most studies and recorded cases of parasite-host association. The Caatinga and Atlantic Forest were the most investigated environments. The objective of this review was to contribute knowledge on the parasitic biodiversity in reptiles from Northeast Brazil, which may help identify gaps in our knowledge and guide future studies.
Topics: Animals; Parasites; Brazil; Checklist; Nematoda; Lizards; Snakes
PubMed: 36637249
DOI: 10.1017/S0022149X22000785 -
The Veterinary Clinics of North... Jan 2020Reptile kidneys maintain a constant extracellular environment within the body. They excrete waste products, maintain normal concentrations of salt and water, regulate... (Review)
Review
Reptile kidneys maintain a constant extracellular environment within the body. They excrete waste products, maintain normal concentrations of salt and water, regulate acid-base balance, and produce hormones and vitamins. The kidneys contain nephrons consisting of glomeruli designed to filter the plasma, Bowman capsules that collect the filtrate, and tubules that resorb most of the filtered water and nutrients while excreting waste metabolites. A Loop of Henle is absent. Therefore, reptile kidneys cannot produce a hypertonic urine. The urinary bladder (if present) and cloaca excrete and absorb additional fluids and electrolytes. A renal portal system is present in all reptiles.
Topics: Animals; Kidney; Reptiles; Urea; Uric Acid; Urinary Bladder
PubMed: 31759442
DOI: 10.1016/j.cvex.2019.08.005 -
Journal of Experimental Zoology. Part... Sep 2021Research focused on understanding the evolutionary factors that shape parity mode evolution among vertebrates have long focused on squamate reptiles (snakes and...
Research focused on understanding the evolutionary factors that shape parity mode evolution among vertebrates have long focused on squamate reptiles (snakes and lizards), which contain all but one of the evolutionary transitions from oviparity to viviparity among extant amniotes. While most hypotheses have focused on the role of cool temperatures in favoring viviparity in thermoregulating snakes and lizards, there is a growing appreciation in the biogeographic literature for the importance of lower oxygen concentrations at high elevations for the evolution of parity mode. However, the physiological mechanisms underlying how hypoxia might reduce fitness, and how viviparity can alleviate this fitness decrement, has not been systematically evaluated. We qualitatively evaluated previous research on reproductive and developmental physiology, and found that (1) hypoxia can negatively affect fitness of squamate embryos, (2) oxygen availability in the circulatory system of adult lizards can be similar or greater than an egg, and (3) gravid females can possess adaptive phenotypic plasticity in response to hypoxia. These findings suggest that the impact of hypoxia on the development and physiology of oviparous and viviparous squamates would be a fruitful area of research for understanding the evolution of viviparity. To that end, we propose an integrative research program for studying hypoxia and the evolution of viviparity in squamates.
Topics: Altitude; Animals; Biological Evolution; Female; Oxygen; Reptiles; Viviparity, Nonmammalian
PubMed: 34254734
DOI: 10.1002/jez.b.23072