Assessing Leukocyte Profiles of Salamanders and Other Amphibians: A Herpetologists’ Guide

Davis, Andrew K.; Maerz, John C.

doi:10.1007/978-1-0716-2659-7_29

Cited by 5 publications

(4 citation statements)

References 34 publications

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“…Otherwise, mean monthly N:L ratios observed in our study between April and August (range: 0.28–0.66; Supplementary Table S1 ) were similar to those reported for most sites sampled by Litmer et al (2020) , which only rarely exceeded 1.0, and thus collectively suggest that few if any of the sub-populations sampled in either study exhibited signals of true physiological stress (i.e. N:L ratio > 1.0; Davis and Maerz, 2022 ).…”

Section: Discussionsupporting

confidence: 86%

“…Because proliferation of neutrophils, a major phagocytic WBC, is one of the first responses to infection, inflammation and stress ( Allender and Fry, 2008 ; Davis et al , 2008 ), elevated N:L ratios are often indicative of an active innate immune response or a relative increase in circulating glucocorticoid hormones (i.e. stress hormones) ( Davis et al , 2008 ; Davis and Maerz, 2022 ). Additionally, proliferation of eosinophils is often indicative of parasitic infection, elevated monocytes are indicative of inflammation and defense against infection (including bacterial), and exposure to environmental pollutants, such as pesticides, has been linked to decreasing lymphocytes ( Christin et al , 2003 ).…”

Section: Methodsmentioning

confidence: 99%

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The habitat quality paradox: loss of riparian forest cover leads to decreased risk of parasitism and improved body condition in an imperiled amphibian

Bodinof Jachowski,

Alaasam,

Blumenthal

et al. 2024

Conservation Physiology

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Amphibian declines are a global phenomenon but responses of populations to specific threats are often context dependent and mediated by individual physiological condition. Habitat degradation due to reduced riparian forest cover and parasitism are two threats facing the hellbender salamander (Cryptobranchus alleganiensis), but their potential to interact in nature remains largely unexplored. We investigated associations between forest cover, parasitic infection and physiology of hellbenders to test the hypotheses that physiological condition responds to infection and/or habitat degradation. We sampled 17 stream reaches in southwest Virginia, USA, on a year-round basis from 2013 to 2016 and recorded 841 captures of 405 unique hellbenders. At each capture we documented prevalence of two blood-associated parasites (a leech and trypanosome) and quantified up to three physiological condition indices (body condition, hematocrit, white blood cell [WBC] differentials). We used generalized linear mixed models to describe spatiotemporal variation in parasitic infection and each condition index. In general, living in the most heavily forested stream reaches, where hellbender density was highest, was associated with the greatest risk of parasitism, elevated neutrophil-to-lymphocyte (N:L) ratios and eosinophils, slightly lower hematocrit and lower mean body condition in hellbenders. All condition indices fluctuated temporally in a manner consistent with seasonal variation in hellbender metabolic demands and breeding phenology and were associated with land use during at least part of the year. Paradoxically, relatively low levels of forest cover appeared to confer a potential advantage to individuals in the form of release from parasites and improved body condition. Despite improved body condition, individuals from less forested areas failed to exhibit fluctuating body condition in response to spawning, which was typical in hellbenders from more forested habitats. We postulate this lack of fluctuation could be due to reduced conspecific competition or reproductive investment and/or high rates of filial cannibalism in response to declining forest cover.

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Section: Discussionsupporting

confidence: 86%

Section: Methodsmentioning

confidence: 99%

The habitat quality paradox: loss of riparian forest cover leads to decreased risk of parasitism and improved body condition in an imperiled amphibian

Bodinof Jachowski,

Alaasam,

Blumenthal

et al. 2024

Conservation Physiology

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“…Because endogenous CORT can increase within minutes following a stressor (e.g. capture), newts were not anaesthetized prior to decapitation and trunk blood collection was completed within 3 min of capture [40]. To measure elevated CORT levels, newts were placed individually in a plastic bag containing 3–5 ml of sterilized nanopure water, vigorously handled for 15 min and allowed an additional 15 min to mount a physiological stress response (total time after capture = 30 min) before collecting trunk blood.…”

Section: Methodsmentioning

confidence: 99%

Effects of exogenous elevation of corticosterone on immunity and the skin microbiome of eastern newts ( Notophthalmus viridescens )

Pereira

Bletz

McCartney

et al. 2023

Phil. Trans. R. Soc. B

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The amphibian chytrid fungus, Batrachochytrium salamandrivorans ( Bsal ) threatens salamander biodiversity. The factors underlying Bsal susceptibility may include glucocorticoid hormones (GCs). The effects of GCs on immunity and disease susceptibility are well studied in mammals, but less is known in other groups, including salamanders. We used Notophthalmus viridescens (eastern newts) to test the hypothesis that GCs modulate salamander immunity. We first determined the dose required to elevate corticosterone (CORT; primary GC in amphibians) to physiologically relevant levels. We then measured immunity (neutrophil lymphocyte ratios, plasma bacterial killing ability (BKA), skin microbiome, splenocytes, melanomacrophage centres (MMCs)) and overall health in newts following treatment with CORT or an oil vehicle control. Treatments were repeated for a short (two treatments over 5 days) or long (18 treatments over 26 days) time period. Contrary to our predictions, most immune and health parameters were similar for CORT and oil-treated newts. Surprisingly, differences in BKA, skin microbiome and MMCs were observed between newts subjected to short- and long-term treatments, regardless of treatment type (CORT, oil vehicle). Taken together, CORT does not appear to be a major factor contributing to immunity in eastern newts, although more studies examining additional immune factors are necessary. This article is part of the theme issue ‘Amphibian immunity: stress, disease and ecoimmunology’.

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“…Basophil percentages vary among frog species, appearing abundantly in African clawed frogs ( Xenopus laevis ) and American bullfrogs ( Lithobates catesbeiana ) [ 35 ] but more sparsely in DuBois’s tree frogs ( Polypedates teraiensis) [ 36 ]. In salamanders, basophils comprise 2–10% of leukocytes in the peripheral blood where basophil maturation takes place [ 37 , 38 ]. Basophils are the most dominant granulocytes in snapping turtles ( Chelydra serpentine ), representing over 50% of circulating blood cells, but they are scarce in marine turtles [ 39 , 40 ].…”

Section: Species Differences Concerning Basophilsmentioning

confidence: 99%

The ontogenesis and heterogeneity of basophils

Park,

Kang

2024

Discovery Immunology

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Summary Basophils are the rarest leukocytes, but they have essential roles in protection against helminths, allergic disorders, autoimmune diseases, and some cancers. For years, the clinical significance of basophils has been neglected because of the lack of proper experimental tools to study them. The development of basophil-specific antibodies and animal models, along with genomic advances like single-cell transcriptomics, has greatly enhanced our understanding of basophil biology. Recent discoveries regarding basophils prompted us to write this review, emphasizing the basophil developmental pathway. In it, we chronologically examine the steps of basophil development in various species, which reveals the apparent advent of basophils predating IgE and basophil’s IgE-independent regulatory role in primitive vertebrates. Then, we cover studies of basophil development in adult bone marrow, and compare those of murine and human basophils, introducing newly identified basophil progenitors and mature basophil subsets, as well as the transcription factors that regulate the transitions between them. Last, we discuss the heterogeneity of tissue-resident basophils, which may develop through extramedullary hematopoiesis. We expect that this review will contribute to a deeper understanding of basophil biology from the intricate aspects of basophil development and differentiation, offering valuable insights for both researchers and clinicians.

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Assessing Leukocyte Profiles of Salamanders and Other Amphibians: A Herpetologists’ Guide

Cited by 5 publications

References 34 publications

The habitat quality paradox: loss of riparian forest cover leads to decreased risk of parasitism and improved body condition in an imperiled amphibian

The habitat quality paradox: loss of riparian forest cover leads to decreased risk of parasitism and improved body condition in an imperiled amphibian

Effects of exogenous elevation of corticosterone on immunity and the skin microbiome of eastern newts ( Notophthalmus viridescens )

The ontogenesis and heterogeneity of basophils

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