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Moeller KT, Brashears JA, Davies S, Demare G, Smith GD, Brusch Iv GA, Simpson RK, DeNardo DF. Corticosterone and immune responses to dehydration in squamate reptiles. J Exp Biol 2023; 226:jeb246257. [PMID: 37955054 DOI: 10.1242/jeb.246257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 11/01/2023] [Indexed: 11/14/2023]
Abstract
Many environments present some degree of seasonal water limitations; organisms that live in such environments must be adapted to survive periods without permanent water access. Often this involves the ability to tolerate dehydration, which can have adverse physiological effects and is typically considered a physiological stressor. While having many functions, the hormone corticosterone (CORT) is often released in response to stressors, yet increasing plasma CORT while dehydrated could be considered maladaptive, especially for species that experience predictable bouts of dehydration and have related coping mechanisms. Elevating CORT could reduce immunocompetence and have other negative physiological effects. Thus, such species likely have CORT and immune responses adapted to experiencing seasonal droughts. We evaluated how dehydration affects CORT and immune function in eight squamate species that naturally experience varied water limitation. We tested whether hydric state affected plasma CORT concentrations and aspects of immunocompetence (lysis, agglutination, bacterial killing ability and white blood cell counts) differently among species based on how seasonally water limited they are and whether this is constrained by phylogeny. The species represented four familial pairs, with one species of each pair inhabiting environments with frequent access to water and one naturally experiencing extended periods (>30 days) with no access to standing water. The effects of dehydration on CORT and immunity varied among species. Increases in CORT were generally not associated with reduced immunocompetence, indicating CORT and immunity might be decoupled in some species. Interspecies variations in responses to dehydration were more clearly grouped by phylogeny than by habitat type.
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Affiliation(s)
- Karla T Moeller
- School of Life Sciences , Arizona State University, Tempe, AZ 85281, USA
| | - Jacqueline A Brashears
- Natural Sciences Department, LaGuardia Community College, Long Island City, NY 11101, USA
| | - Scott Davies
- Department of Biological Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Guillaume Demare
- Museum für Naturkunde - Leibniz Institute for Evolution and Biodiversity Research, Invalidenstraße 43, 10115 Berlin, Germany
| | - Geoffrey D Smith
- Department of Biological Sciences, Utah Tech University, St George, UT 84770, USA
| | - George A Brusch Iv
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92096, USA
| | - Richard K Simpson
- Nature Conservancy of Canada, Ontario Region, 245 Eglinton Ave East, Suite 410, Toronto, ON, Canada, M4P 3J1
| | - Dale F DeNardo
- School of Life Sciences , Arizona State University, Tempe, AZ 85281, USA
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Past, Present, and Future of Naturally Occurring Antimicrobials Related to Snake Venoms. Animals (Basel) 2023; 13:ani13040744. [PMID: 36830531 PMCID: PMC9952678 DOI: 10.3390/ani13040744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/10/2023] [Accepted: 02/11/2023] [Indexed: 02/22/2023] Open
Abstract
This review focuses on proteins and peptides with antimicrobial activity because these biopolymers can be useful in the fight against infectious diseases and to overcome the critical problem of microbial resistance to antibiotics. In fact, snakes show the highest diversification among reptiles, surviving in various environments; their innate immunity is similar to mammals and the response of their plasma to bacteria and fungi has been explored mainly in ecological studies. Snake venoms are a rich source of components that have a variety of biological functions. Among them are proteins like lectins, metalloproteinases, serine proteinases, L-amino acid oxidases, phospholipases type A2, cysteine-rich secretory proteins, as well as many oligopeptides, such as waprins, cardiotoxins, cathelicidins, and β-defensins. In vitro, these biomolecules were shown to be active against bacteria, fungi, parasites, and viruses that are pathogenic to humans. Not only cathelicidins, but all other proteins and oligopeptides from snake venom have been proteolyzed to provide short antimicrobial peptides, or for use as templates for developing a variety of short unnatural sequences based on their structures. In addition to organizing and discussing an expressive amount of information, this review also describes new β-defensin sequences of Sistrurus miliarius that can lead to novel peptide-based antimicrobial agents, using a multidisciplinary approach that includes sequence phylogeny.
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Field EK, Hartzheim A, Terry J, Dawson G, Haydt N, Neuman-Lee LA. Reptilian Innate Immunology and Ecoimmunology: What Do We Know and Where Are We Going? Integr Comp Biol 2022; 62:1557-1571. [PMID: 35833292 DOI: 10.1093/icb/icac116] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 01/05/2023] Open
Abstract
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.
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Affiliation(s)
- Emily K Field
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
| | - Alyssa Hartzheim
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
| | - Jennifer Terry
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
| | - Grant Dawson
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
| | - Natalie Haydt
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
| | - Lorin A Neuman-Lee
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
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Sandfoss MR, Brischoux F, Lillywhite HB. Intraspecific investigation of dehydration-enhanced innate immune performance and endocrine stress response to sublethal dehydration in a semi-aquatic species of pit viper. J Exp Biol 2022; 225:276533. [PMID: 35946379 DOI: 10.1242/jeb.243894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 08/03/2022] [Indexed: 11/20/2022]
Abstract
Sublethal dehydration can cause negative physiological effects, but recent studies investigating the sub-lethal effects of dehydration on innate immune performance in reptiles have found a positive correlation between innate immune response and plasma osmolality. To investigate if this is an adaptive trait that evolved in response to dehydration in populations inhabiting water-scarce environments, we sampled free-ranging cottonmouths (n=26 adult cottonmouths) from two populations inhabiting contrasting environments in terms of water availability: Snake Key (n=12), an island with no permanent sources of fresh water and Paynes Prairie (n=14), a flooded freshwater prairie. In addition to field surveys, we manipulated the hydration state of 17 cottonmouths (Paynes Prairie n=9, Snake Key n=8) in a laboratory setting and measured the response of corticosterone and innate immune performance to dehydration with the aim of identifying any correlation or trade-offs between them. We measured corticosterone of cottonmouths at a baseline level and then again following a 60-min stress test when at three hydration states: hydrated, dehydrated, and rehydrated. We found that innate immune performance improved with dehydration and then returned to baseline levels within 48 hours of rehydration, which agrees with previous research in reptiles. Despite the frequent exposure of cottonmouths on Snake Key to dehydrating conditions, we did not find cottonmouths inhabiting the island to show a greater magnitude or more prolonged immune response compared to cottonmouths from Paynes Prairie. We also found a positive association between dehydration and corticosterone values.
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Affiliation(s)
- Mark R Sandfoss
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - François Brischoux
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 CNRS and La Rochelle Université, 79360 Villiers en Bois, France
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Haskins DL, Brown MK, Meichner K, Tuberville TD, Gogal RM. Peripheral blood hematology, plasma biochemistry, and the optimization of an in vitro immune-based assay in the brown watersnake ( Nerodia taxispilota). J Immunoassay Immunochem 2020; 42:4-18. [PMID: 32808875 DOI: 10.1080/15321819.2020.1808479] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Reptiles represent a phylogenetic lineage that provides a unique link between ectothermic anamniotes and endothermic amniotes. Compared to mammalian and avian species, our understanding of the reptilian immune system is greatly lacking. This gap in knowledge is largely due to an absence of established immune-based assays or specific reagents for these species. In the present study, brown watersnakes (Nerodia taxispilota) were live-captured in the wild, sexed, weighed, measured, bled via the caudal vein, and released. At 24 hr post-collection, peripheral blood leukocytes were enriched and evaluated with an established mammalian in-vitro lymphocyte proliferation assay. Snake peripheral blood leukocyte enrichment yielded >90% lymphocytes with viabilities averaging 81.5%. Baseline physiologic data for N. taxispilota, including hematology and total solids, leukocyte differentials, cell recovery, and plasma biochemistry, were also collected. Cells cultured with Concanavalin A exhibited significantly increased proliferation at both 72 and 96 hr. These preliminary results show that enriched peripheral blood from wild-caught N. taxispilota provides a sufficient yield of leukocytes that can be cultured and functionally evaluated using a standard mammalian in-vitro immune-based assay.
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Affiliation(s)
- David Lee Haskins
- Interdisciplinary Toxicology Program, University of Georgia, Athens, Georgia, USA.,University of Georgia Savannah River Ecology Laboratory, Aiken, South Carolina, USA.,Savannah River Ecology Laboratory, Aiken, South Carolina, USA
| | - M Kyle Brown
- University of Georgia Savannah River Ecology Laboratory, Aiken, South Carolina, USA.,Savannah River Ecology Laboratory, Aiken, South Carolina, USA
| | - Kristina Meichner
- Department of Pathology, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA
| | | | - Robert M Gogal
- Department of Biosciences and Diagnostic Imaging, College of Veterinary Medicine, University of Georgia, Athens, Georgia, Georgia, USA
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Ontogeny of strike performance in ball pythons (Python regius): a three-year longitudinal study. ZOOLOGY 2020; 140:125780. [PMID: 32289748 DOI: 10.1016/j.zool.2020.125780] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 11/21/2022]
Abstract
The rapid strike of snakes has long been of interest in terms of mechanical performance. Recently, several nonvenomous taxa have been found to strike with the same incredible strike velocity and acceleration as the high-performing vipers. However, little is known regarding how these patterns change through ontogeny. Here I present ontogenetic strike data on ten ball pythons (Python regius) over a three year time period, from birth to sexual maturity. I found that performance declined rapidly over the first 18 months in nearly all kinematic measures. This puts the adult data out of the currently developing trend of high performance being maintained across the diversity of snakes. The underlying cause of the decline in performance is unclear, but there are several avenues of behavior, morphology, biomechanics, and ecology to be investigated.
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