Scaling of morphology and ultrastructure of hearts among wild African antelope

Show simple item record Snelling, Edward P. Maloney, Shane K. Farrell, Anthony P. Meyer, L.C.R. (Leith Carl Rodney) Izwan, Adian Fuller, Andrea Mitchell, Duncan Haw, Anna Costello, Mary-Ann Seymour, Roger S. 2019-03-05T13:41:59Z 2018-09
dc.description.abstract The hearts of smaller mammals tend to operate at higher mass-specific mechanical work rates than those of larger mammals. The ultrastructural characteristics of the heart that allow for such variation in work rate still is largely unknown. We have used perfusion-fixation, transmission electron microscopy and stereology to assess the morphology and anatomical aerobic power density of the heart as a function of body mass across six species of wild African antelope differing by approximately 20-fold in body mass. The survival of wild antelope, as prey animals, depends on competent cardiovascular performance. We found that relative heart mass (g kg-1 body mass) decreases with body mass according to a power equation with an exponent of –0.12 ± 0.07 (± 95% CI) (P = 0.0027). Likewise, capillary length density (km cm-3 of cardiomyocyte), mitochondrial volume density (fraction of cardiomyocyte), and mitochondrial inner membrane surface density (m2 cm-3 of mitochondria) also decrease with body mass with exponents of –0.17 ± 0.16 (P = 0.039), –0.06 ± 0.05 (P = 0.018), and –0.07 ± 0.05 (P = 0.015), respectively, trends likely to be associated with the greater mass-specific mechanical work rates of the hearts in smaller antelope. Finally, we found proportionality between quantitative characteristics of a structure responsible for the delivery of oxygen (total capillary length) and those of a structure that ultimately uses that oxygen (total mitochondrial inner membrane surface area), which provides support for the economic principle of symmorphosis at the cellular level of the oxygen cascade in an aerobic organ. en_ZA
dc.description.department Paraclinical Sciences en_ZA
dc.description.embargo 2019-09-05
dc.description.librarian am2019 en_ZA
dc.description.sponsorship An Australian Research Council Discovery Project Award to RSS, SKM and APF [DP-120102081], a South African Claude Leon Foundation Postdoctoral Fellowship to EPS, and a Natural Sciences and Engineering Research Council of Canada Discovery Grant to APF. en_ZA
dc.description.uri en_ZA
dc.identifier.citation Snelling E.P., Maloney S.K., Farrell A.P. et al. 2018, 'Scaling of morphology and ultrastructure of hearts among wild African antelope', Journal of Experimental Biology, vol. 221, art. jeb184713, pp.1-9. en_ZA
dc.identifier.issn 0022-0949 (print)
dc.identifier.issn 1477-9145 (online)
dc.identifier.other 10.1242/jeb.184713
dc.language.iso en en_ZA
dc.publisher Company of Biologists en_ZA
dc.rights © 2018. Published by The Company of Biologists Ltd. en_ZA
dc.subject Capillarity en_ZA
dc.subject Cardiac en_ZA
dc.subject Mammal en_ZA
dc.subject Mitochondria en_ZA
dc.subject Myofibrils en_ZA
dc.subject Predation en_ZA
dc.title Scaling of morphology and ultrastructure of hearts among wild African antelope en_ZA
dc.type Article en_ZA

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