Biochemistry and Physiology of Alligator Metabolism<i>in vivo</i>

Coulson, Roland A.; Herbert, Jack D.; Coulson, Thomas D.

doi:10.1093/icb/29.3.921

Cited by 35 publications

(16 citation statements)

References 9 publications

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“…Heart mass averages about 0.4%-0.7% of body mass in mammals and 0.8%-1.2% in birds (Poupa and Ostádal 1969;Bishop 1997;Seymour and Blaylock 2000), but it is only 0.19%-0.32% in most reptiles (Poupa and Lindström 1983;Seymour 1987;Farrell et al 1998). In alligators, heart mass decreases from 0.25% at 1 kg body mass to 0.15% at 70 kg and 0.125% at 124 kg (Coulson et al 1989).…”

Section: Introductionmentioning

confidence: 94%

Evidence for Endothermic Ancestors of Crocodiles at the Stem of Archosaur Evolution

Seymour¹,

Bennett‐Stamper²,

Johnston³

et al. 2004

Physiological and Biochemical Zoology

158

147

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. ABSTRACT Physiological, anatomical, and developmental features of the crocodilian heart support the paleontological evidence that the ancestors of living crocodilians were active and endothermic, but the lineage reverted to ectothermy when it invaded the aquatic, ambush predator niche. In endotherms, there is a functional nexus between high metabolic rates, high blood flow rates, and complete separation of high systemic blood pressure from low pulmonary blood pressure in a four-chambered heart. Ectotherms generally lack all of these characteristics, but crocodilians retain a four-chambered heart. However, crocodilians have a neurally controlled, pulmonary bypass shunt that is functional in diving. Shunting occurs outside of the heart and involves the left aortic arch that originates from the right ventricle, the foramen of Panizza between the left and right aortic arches, and the cog-tooth valve at the base of the pulmonary artery. Developmental studies show that all of these uniquely crocodilian features are secondarily derived, indicating a shift from the complete separation of blood flow of endotherms to the controlled shunting of ectotherms. We present other evidence for endothermy in stem archosaurs and suggest that some dinosaurs may have inherited the trait. The University of Chicago Press

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Section: Introductionmentioning

confidence: 94%

Evidence for Endothermic Ancestors of Crocodiles at the Stem of Archosaur Evolution

Seymour¹,

Bennett‐Stamper²,

Johnston³

et al. 2004

Physiological and Biochemical Zoology

158

147

View full text Add to dashboard Cite

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“…during the warmer Eocene (Estes and Hutchinson 1980). However, ectothermy, temperature-dependent sex determination, and their subaquatic nature limit the range of climates a population can be sustained in (King and Dobbs 1975;Coulson et al 1989;Brandt and Mazzotti 1990;Emshwiller and Gleeson 1997;Thorbjarnarson and Wang 2010). Because they live in their own depositional environment and possess dense bones and numerous osteological parts (osteoderms and constantly replaced teeth), they have a good fossil record and are less likely to be affected by rock-record bias produced by unfavorable fossilization conditions than many other organisms.…”

Section: Resultsmentioning

confidence: 99%

Patterns in alligatorine evolution

Miller-Camp¹

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Alligatorines are a diverse clade of crocodylians whose history spans the entire Cenozoic. They are suited to answer a variety of questions with far-reaching impacts due to their physiology and preservation potential, and have been the subject of several phylogenetic, biogeographic, and diversity analyses. However, prior phylogenetic analyses had poor resolution and several putative alligatorines have never been included, while other analyses would be more informative and accurate if viewed through the context of evolutionary history. Here, I analyze the phylogenetics, taxonomy, biogeography, ecomorphology, and diversity dynamics of alligatorines. An almost fully resolved phylogenetic hypothesis returns two major clades within Alligatorinae and includes several putative alligatorines not previously analyzed. The clade originated in North America and dispersed to Europe and Asia three to five times via at least three different corridors at high latitudes when climate-and potentially salinity-were favorable, likely including the recently discovered subaerial Lomonosov Ridge. The modern American alligator is a dietary generalist, but evolved from a durophagous specialist, contrary to the intuitive reasoning of the "Law of the Unspecialized". It was able to do so by entering the generalist niche vacated by basal crocodyloids following their extirpation from mid-latitude North America. Alligatorine diversity only weakly tracks climate change and does not track the rock record excepting swampy environments. Alligatorine diversity correlates with climate change. Climate change correlates with rocks, though in a more complicated pattern. Some diversity metrics correlate with some aspects of the rock record, but predominantly do not. There is more support for the common-cause hypothesis than for rock record bias driving apparent alligatorine diversity. Overall, alligator evolution exhibits a pattern of being more diverse taxonomically and morphologically when the climate is warmer, and dispersing during the warmest and wettest of those times.

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“…The thermal profile of alligator ChT activity reflects the preferred body temperatures of these animals. Alligators thermoregulate to an internal body temperature of 31˚C -32˚C [30], where many physiological parameters such as cardiac function [31] and general metabolism [32], are optimized. In addition, many immunological parameters, such as serum complement [33], phospholipase A 2 [34], and dipeptidyl peptidase IV [35] activities have been shown to exhibit comparable thermal characteristics.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Chitotriosidase Enzyme Activity in the Serum of the American Alligator (<i>Alligator mississippiensis</i>)

Kidder¹,

Falconi²,

Merchant³

2018

ABC

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Chitotriosidase (ChT) is an endoglucosaminidase enzyme that cleaves chitinous substrates and has been strongly associated with innate immune activity and the ability to identify non-selftissues. This enzyme activity was detected and characterized the serum from the American alligator (Alligator mississippiensis) using a fluorometric probe. Alligator serum exhibited volume-dependent activity, with activity (2.1 ± 0.3 μmol/min) observed at dilutions as low as a 1:150, and maximum activity (5.2 ± 0.6 μmol/min) measured at a dilution of 1:30. Alligator serum ChT showed linear activity for approximately 20 min, at which time activity decreased exponentially, presumably due to the depletion of substrate. In addition, the ChT activity in alligator serum was temperature-dependent with low activity at 5˚C, a sharp increase from 10˚C-30˚C, and maximal activity from 30˚C-40˚C. The activity was inhibited in the presence of water-soluble chitin, but not mannan, indicating the specificity of the enzyme. The presence of ChT in alligator serum is likely to be partially responsible for the potent innate immune system of these crocodylians, and particularly antifungal activities.

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Biochemistry and Physiology of Alligator Metabolismin vivo

Cited by 35 publications

References 9 publications

Evidence for Endothermic Ancestors of Crocodiles at the Stem of Archosaur Evolution

Evidence for Endothermic Ancestors of Crocodiles at the Stem of Archosaur Evolution

Patterns in alligatorine evolution

Characterization of Chitotriosidase Enzyme Activity in the Serum of the American Alligator (<i>Alligator mississippiensis</i>)

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Biochemistry and Physiology of Alligator Metabolismin vivo

Cited by 35 publications

References 9 publications

Evidence for Endothermic Ancestors of Crocodiles at the Stem of Archosaur Evolution

Evidence for Endothermic Ancestors of Crocodiles at the Stem of Archosaur Evolution

Patterns in alligatorine evolution

Characterization of Chitotriosidase Enzyme Activity in the Serum of the American Alligator (&lt;i&gt;Alligator mississippiensis&lt;/i&gt;)

Contact Info

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About

Characterization of Chitotriosidase Enzyme Activity in the Serum of the American Alligator (<i>Alligator mississippiensis</i>)