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Fletcher LE, Martin LB, Downs CJ. Leukocyte Concentrations Are Isometric in Reptiles Unlike in Endotherms. Physiol Biochem Zool 2023; 96:405-417. [PMID: 38237194 DOI: 10.1086/727050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
AbstractHow do large and small reptiles defend against infections, given the consequences of body mass for physiology and disease transmission? Functionally equivalent mammalian and avian granulocytes increased disproportionately with body mass (i.e., scaled hypermetrically), such that large organisms had higher concentrations than expected by a prediction of proportional protection across sizes. However, as these scaling relationships were derived from endothermic animals, they do not necessarily inform the scaling of leukocyte concentration for ectothermic reptiles that have a different physiology and evolutionary history. Here, we asked whether and how lymphocyte and heterophil concentrations relate to body mass among more than 120 reptile species. We compared these relationships to those found in birds and mammals and to existing scaling frameworks (i.e., protecton, complexity, rate of metabolism, or safety factor hypotheses). Both lymphocyte and heterophil concentrations scaled almost isometrically among reptiles. In contrast, functionally equivalent granulocytes scaled hypermetrically and lymphocytes scaled isometrically in birds and mammals. Life history traits were also poor predictors of variation in reptilian heterophil and lymphocyte concentrations. Our results provide insight into differences in immune protection in birds and mammals relative to that in reptiles through a comparative lens. The shape of scaling relationships differs, which should be considered when modeling disease dynamics among these groups.
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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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Soliman SA, Abd-Elhafeez HH, Mohamed NE, Alrashdi BM, Alghamdi AAA, Elmansi A, Salah AS, El-Gendy SAA, Rutland CS, Massoud D. Morphological and cytochemical characteristics of Varanus niloticus (Squamata, Varanidae) blood cells. Microsc Res Tech 2023; 86:600-613. [PMID: 36722417 DOI: 10.1002/jemt.24298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 12/21/2022] [Accepted: 01/13/2023] [Indexed: 02/02/2023]
Abstract
Varanus niloticus is a lizard residing within the Varanidae family. To date no studies detailing its blood morphology and characteristics have been conducted. This study used histologically stained blood and bone marrow samples to visualize the cells and their characteristics. The erythrocytes were nucleated, these nuclei were located in the middle of the elliptical cells. Hemoglobin filled the erythrocyte cytoplasm. Eosinophils were large cells with lobed nuclei and spherical acidophilic granules. Large granulocytes called heterophils were present and characterized by their fusiform/pleomorphic cytoplasmic granules. Small spherical granulocytes, known as basophils, presented with round, deeply stained metachromatic granules that gave the cytoplasm a dusty or cobblestoned appearance which was able to cover the nucleus, which in turn had an unusual shape. Thrombocytes ranged in shape from ellipsoidal to fusiform. They featured an elliptical, centrally located nucleus and a pale cytoplasm, with small vacuoles, and fine acidophilic granulation. The smallest variety of non-granular leukocytes was the lymphocytes. Their cytoplasm was sparse, finely granular, light blue, had tiny cytoplasmic projections, featuring a high nucleus: cytoplasm ratio. Larger and smaller sized populations of lymphocytes were distinguished, with the larger cells similar in size to azurophils. In general, the pleomorphic monocytes were the biggest mononuclear leucocytes, displaying cytoplasmic projections. Their nuclei were ovoid, kidney- or bean-shaped, with vacuolated and granular cytoplasms. Round cells were common among the monocytic azurophils, and they had a granular cytoplasm, and their nuclei were typically eccentric. The present research identifies the cell types and morphologies within the Varanus niloticus. HIGHLIGHTS: H&E, PAS, toluidine blue, methylene blue, and Safranin O stains provided morphological and morphometric descriptions of Varanus niloticus blood cells from blood smears and bone marrow. The Varanus niloticus had nucleated erythrocytes and white blood cells, mostly granulocytes (heterophils, eosinophils, and basophils) and mononuclear cells (azurophils, lymphocytes, and monocytes). Aquatic vertebrate Varanus niloticus had larger erythrocytes than terrestrial counterparts. Blood cell morphological and cytochemical features were similar to other reptilian species, with some species-specific differences, which likely accommodate differing environmental conditions. These results may help clinical researchers track the pathological conditions and support conservation of these wild animals.
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Affiliation(s)
- Soha A Soliman
- Department of Histology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt
| | - Hanan H Abd-Elhafeez
- Department of Cell and Tissues, Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt
| | - Nor-Elhoda Mohamed
- Faculty of Science, Biomedicine Branch, University of Science & Technology in Zewail City, Cairo, Egypt
| | - Barakat M Alrashdi
- Biology Department, College of Science, Jouf University, Sakaka, Saudi Arabia
| | - Abdullah A A Alghamdi
- Department of Biology, Faculty of Science, Al-Baha University, Al-Baha, Saudi Arabia
| | - Ahmed Elmansi
- Biology Department, Faculty of Science, King Khalid University, Abha, Saudi Arabia.,Zoology Department, Faculty of Science, Mansoura University, Mansoura, Egypt
| | - Abdallah S Salah
- Department of Aquaculture, Faculty of Aquatic and Fisheries Sciences, Kafrelsheikh University, Kafrelsheikh, Egypt.,Institute of Aquaculture, University of Stirling, Stirling, UK
| | - Samir A A El-Gendy
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Alexandria University, Alexandria, Egypt
| | - Catrin S Rutland
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Science, University of Nottingham, Nottingham, UK
| | - Diaa Massoud
- Biology Department, College of Science, Jouf University, Sakaka, Saudi Arabia.,Department of Zoology, Faculty of Science, Fayoum University, Fayoum, Egypt
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4
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Dervas E, Michalopoulou E, Liesegang A, Novacco M, Schwarzenberger F, Hetzel U, Kipar A. Haematology, biochemistry and morphological features of peripheral blood cells in captive Boa constrictor. CONSERVATION PHYSIOLOGY 2023; 11:coad001. [PMID: 36726862 PMCID: PMC9885740 DOI: 10.1093/conphys/coad001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 12/21/2022] [Accepted: 01/06/2023] [Indexed: 06/18/2023]
Abstract
The common boa (Boa constrictor) belongs to the family Boidae and represents one of the most popular traded and kept snake species in captivity. The early diagnosis, prevention and prophylaxis of diseases in this species, and in reptiles in general, still pose major challenges, also due to the lack of reliable reference values. This prompted us to conduct a study on clinically healthy captive B. constrictor to assess their basic health parameters in the blood (haematological and biochemical values, stress markers). Several parameters differed significantly between younger (<3 years) and older (≥3 years) boas; in the latter, the percentages of eosinophils, the haemoglobin and haematocrit levels, as well as the albumin and total protein levels, were higher. In male snakes, cholesterol levels were significantly higher than in females. Light and electron microscopy as well as immunohistochemistry served to identify and determine the morphological features of peripheral blood cells, that is, heterophils, basophils, eosinophils, azurophils, monocytes, lymphocytes, thrombocytes and erythrocytes. Leukocyte subpopulations, that is, T and B cells and monocytes, were also identified based on specific marker expression. The study provides data on haematological, biochemical and stress hormone levels, suitable as reference values, and on the blood cell morphology of B. constrictor which can serve as a guideline for further research on this species.
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Affiliation(s)
- E Dervas
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 268, 8057, Zurich, Switzerland
| | - E Michalopoulou
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 268, 8057, Zurich, Switzerland
| | - A Liesegang
- Institute for Animal Nutrition and Dietetics, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 270, 8057, Zurich, Switzerland
| | - M Novacco
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, 8057, Zurich, Switzerland
| | - F Schwarzenberger
- Unit of Physiology, Pathophysiology and Experimental Endocrinology, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | - U Hetzel
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 268, 8057, Zurich, Switzerland
| | - A Kipar
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 268, 8057, Zurich, Switzerland
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5
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Gomes FR, Madelaire CB, Moretti EH, Titon SCM, Assis VR. Immunoendocrinology and Ecoimmunology in Brazilian Anurans. Integr Comp Biol 2022; 62:1654-1670. [PMID: 35411921 DOI: 10.1093/icb/icac014] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
This paper reviews several aspects of immunoendocrinology and ecoimmunology in Brazilian species of anurans under investigation for more than a decade, including (1) patterns of annual covariation of circulating steroids, calling behavior and innate immunity, (2) endocrine and immune correlates of calling performance, (3) behavioral and physiological correlates of parasite load, (4) thermal sensitivity of immune function, and (5) endocrine and immunomodulation by experimental exposure to acute and chronic stressors, as well as to endocrine manipulations and simulated infections. Integrated results have shown an immunoprotective role of increased steroid plasma levels during reproductive activity in calling males. Moreover, a higher helminth parasite load is associated with changes in several behavioral and physiological traits under field conditions. We also found anuran innate immunity is generally characterized by eurythermy, with maximal performance observed in temperatures close to normal and fever thermal preferendum. Moreover, the aerobic scope of innate immune response is decreased at fever thermal preferendum. Experimental exposure to stressors results in increased corticosterone plasma levels and immune redistribution, with an impact on immune function depending on the duration of the stress exposure. Interestingly, the fate of immunomodulation by chronic stressors also depends in part on individual body condition. Acute treatment with corticosterone generally enhances immune function, while prolonged exposure results in immunosuppression. Still, the results of hormonal treatment are complex and depend on the dose, duration of treatment, and the immune variable considered. Finally, simulated infection results in complex modulation of the expression of cytokines, increased immune function, activation of the Hypothalamus-Pituitary-Interrenal axis, and decreased activity of the Hypothalamus-Pituitary-Gonadal axis, as well as reduced melatonin plasma levels, suggesting that anurans have a functional Immune-Pineal axis, homologous to that previously described for mammals. These integrated and complementary approaches have contributed to a better understanding of physiological mechanisms and processes, as well as ecological and evolutionary implications of anuran immunoendocrinology.
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Affiliation(s)
- Fernando Ribeiro Gomes
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, trav. 14, 101, São Paulo, SP 05508-090, Brasil
| | - Carla Bonetti Madelaire
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, trav. 14, 101, São Paulo, SP 05508-090, Brasil.,School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Eduardo Hermógenes Moretti
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Professor Lineu Prestes, 1730, São Paulo, SP 05508-900, Brasil
| | - Stefanny Christie Monteiro Titon
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, trav. 14, 101, São Paulo, SP 05508-090, Brasil
| | - Vania Regina Assis
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, trav. 14, 101, São Paulo, SP 05508-090, Brasil
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Slama SL, Williams GS, Painter MN, Sheedy MD, Sandmeier FC. Temperature and Season Influence Phagocytosis by B1 Lymphocytes in the Mojave Desert Tortoise. Integr Comp Biol 2022; 62:1683-1692. [PMID: 35536570 DOI: 10.1093/icb/icac025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/08/2022] [Accepted: 04/11/2022] [Indexed: 01/05/2023] Open
Abstract
Lymphocytes are usually interpreted as functioning in adaptive immunity despite evidence that large proportions of these cells (B1 lymphocytes) have innate immune functions, including phagocytosis, in the peripheral blood of ectothermic vertebrates. We used a recently optimized assay to assess environmental influences on phagocytic activity of lymphocytes isolated from the Mojave desert tortoise (Gopherus agassizii). Previous studies suggest that lymphocytes in this species are associated with reduced pathogen loads, especially in cooler climates, and that lymphocyte numbers fluctuate seasonally. Thus, we evaluated thermal dependence of phagocytic activity in vitro and across seasons. While B1 lymphocytes appeared to be cold-adapted and always increased phagocytosis at cool temperatures, we also found evidence of thermal acclimation. Tortoises upregulated these lymphocytes during cooler seasons in the fall as their preferred body temperatures dropped, and phagocytosis also increased in efficiency during this same time. Like many other ectothermic species, populations of desert tortoises are in decline, in part due to a cold-adapted pathogen that causes chronic respiratory disease. Future studies, similarly focused on the function of B1 lymphocytes, could serve to uncover new patterns in thermal acclimation of immune functions and disease ecology across taxa of ectothermic vertebrates.
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Affiliation(s)
- Summer L Slama
- Department of Biology, Colorado State University-Pueblo, 2200 Bonforte Blvd Pueblo, CO 81001, USA
| | - Grace S Williams
- Department of Biology, Colorado State University-Pueblo, 2200 Bonforte Blvd Pueblo, CO 81001, USA
| | - Mariah N Painter
- Department of Biology, Colorado State University-Pueblo, 2200 Bonforte Blvd Pueblo, CO 81001, USA
| | - Maxwell D Sheedy
- Department of Biology, Colorado State University-Pueblo, 2200 Bonforte Blvd Pueblo, CO 81001, USA
| | - Franziska C Sandmeier
- Department of Biology, Colorado State University-Pueblo, 2200 Bonforte Blvd Pueblo, CO 81001, USA
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7
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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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8
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PARASITOLOGIC AND PATHOLOGIC STUDY OF FREE-RANGING SOUTH AMERICAN RATTLESNAKES ( CROTALUS DURISSUS TERRIFICUS) IN BRAZIL. J Zoo Wildl Med 2022; 53:515-527. [DOI: 10.1638/2021-0065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2022] [Indexed: 11/21/2022] Open
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9
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Singh A, Singh R, Tripathi MK. Evaluation of the sex steroids mediated modulation of leucocyte immune responses in an ophidian Natrix piscator. Curr Res Physiol 2022; 5:355-360. [PMID: 36185818 PMCID: PMC9519393 DOI: 10.1016/j.crphys.2022.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 08/23/2022] [Accepted: 09/20/2022] [Indexed: 11/28/2022] Open
Abstract
The immune-suppressive role of sex steroids in mammals is well documented, but information on other vertebrates is limited. The present study was planned to analyze the effect of testosterone and progesterone in the modulation of immune functions of leucocytes in a reptile, Natrix piscator. Reptiles are unique organisms and this study is novel in that it provides an insight into immune-reproductive cross-talk in a reptile. Leucocytes were isolated from peripheral blood, cultured with different concentrations of testosterone and progesterone and different immune parameters like phagocytosis, superoxide production, and nitrite release were assessed. Lymphocytes were isolated and cell-mediated immunity was assessed through proliferation responses utilizing tetrazolium salt. Concentration-dependent suppressive effects of both the steroids on immune responses were observed. A differential suppressive effect of testosterone was also observed when a lymphocyte proliferation assay was studied. Using receptor antagonists such as cyproterone acetate and mifepristone restored the immune responses of cultured cells. It was summarized that gonadal steroids mediate a direct suppressive effect on innate and cell-mediated immune responses of blood immune cells. It was concluded that when gonadal steroids are high in reproductive seasons, the immune functions are suppressed to gain optimum reproductive success. Reptilian immune responses are differentially affected by sex steroids. Testosterone interacts with nuclear receptors and suppress proliferative responses of lymphocytes. Superoxide anion production by blood immune cells are inhibited by gonadal steroids. Use of receptor antagonists resulted in amelioration of immune responses indicating the direct action of steroids.
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10
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Slama SL, Painter MN, Sheedy MD, Sandmeier FC. Quantifying phagocytic lymphocytes in ectothermic vertebrates: A simplified technique for assessing immune function. Methods Ecol Evol 2020. [DOI: 10.1111/2041-210x.13533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Zimmerman LM. The reptilian perspective on vertebrate immunity: 10 years of progress. J Exp Biol 2020; 223:223/21/jeb214171. [DOI: 10.1242/jeb.214171] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
ABSTRACT
Ten years ago, ‘Understanding the vertebrate immune system: insights from the reptilian perspective’ was published. At the time, our understanding of the reptilian immune system lagged behind that of birds, mammals, fish and amphibians. Since then, great progress has been made in elucidating the mechanisms of reptilian immunity. Here, I review recent discoveries associated with the recognition of pathogens, effector mechanisms and memory responses in reptiles. Moreover, I put forward key questions to drive the next 10 years of research, including how reptiles are able to balance robust innate mechanisms with avoiding self-damage, how B cells and antibodies are used in immune defense and whether innate mechanisms can display the hallmarks of memory. Finally, I briefly discuss the links between our mechanistic understanding of the reptilian immune system and the field of eco-immunology. Overall, the field of reptile immunology is poised to contribute greatly to our understanding of vertebrate immunity in the next 10 years.
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12
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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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13
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Olsson M, Geraghty NJ, Wapstra E, Wilson M. Telomere length varies substantially between blood cell types in a reptile. ROYAL SOCIETY OPEN SCIENCE 2020; 7:192136. [PMID: 32742684 PMCID: PMC7353983 DOI: 10.1098/rsos.192136] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 05/12/2020] [Indexed: 05/19/2023]
Abstract
Telomeres are repeat sequences of non-coding DNA-protein molecules that cap or intersperse metazoan chromosomes. Interest in telomeres has increased exponentially in recent years, to now include their ongoing dynamics and evolution within natural populations where individuals vary in telomere attributes. Phylogenetic analyses show profound differences in telomere length across non-model taxa. However, telomeres may also differ in length within individuals and between tissues. The latter becomes a potential source of error when researchers use different tissues for extracting DNA for telomere analysis and scientific inference. A commonly used tissue type for assessing telomere length is blood, a tissue that itself varies in terms of nuclear content among taxa, in particular to what degree their thrombocytes and red blood cells (RBCs) contain nuclei or not. Specifically, when RBCs lack nuclei, leucocytes become the main source of telomeric DNA. RBCs and leucocytes differ in lifespan and how long they have been exposed to 'senescence' and erosion effects. We report on a study in which cells in whole blood from individual Australian painted dragon lizards (Ctenophorus pictus) were identified using flow cytometry and their telomere length simultaneously measured. Lymphocyte telomeres were on average 270% longer than RBC telomeres, and in azurophils (a reptilian monocyte), telomeres were more than 388% longer than those in RBCs. If this variation in telomere length among different blood cell types is a widespread phenomenon, and DNA for comparative telomere analyses are sourced from whole blood, evolutionary inference of telomere traits among taxa may be seriously complicated by the blood cell type comprising the main source of DNA.
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Affiliation(s)
- Mats Olsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- The School of Earth, Atmospheric and Life Sciences, University of Wollongong, Australia
- Author for correspondence: Mats Olsson e-mail:
| | - Nicholas J. Geraghty
- The School of Earth, Atmospheric and Life Sciences, University of Wollongong, Australia
| | - Erik Wapstra
- School of Natural Sciences, University of Tasmania, Hobart, Australia
| | - Mark Wilson
- School of Chemistry and Molecular Bioscience, Illawarra Health and Medical Research Institute, University of Wollongong, Australia
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