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Paralytic hypo‐energetic state facilitates anoxia tolerance despite ionic imbalance in adult Drosophila melanogaster
Author(s) -
Campbell Jacob B.,
Andersen Mads Kuhlmann,
Overgaard Johannes,
Harrison Jon F.
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.602.4
Subject(s) - hemolymph , drosophila melanogaster , melanogaster , biology , hypoxia (environmental) , respiration , oxygen , medicine , endocrinology , chemistry , biochemistry , anatomy , organic chemistry , gene
Oxygen limitation plays a key role in many pathologies, and yet we still lack a fundamental understanding of the mechanisms responsible for variation in anoxia tolerance. Most vertebrate studies suggest that anoxia tolerance involves the ability to maintain cellular ATP despite the loss of aerobic metabolism. However, insects such as adult D. melanogaster are able to survive long periods of anoxia (LT50: ~8 h) in a hypo‐energetic state characterized by low [ATP]. In this study, we tested for possible mechanisms that allow D. melanogaster adults to survive long periods of anoxia. The adults are paralyzed within 30 sec and after two hours of anoxia, ATP was 3% of normal, [K + ] o increased approximately threefold, pH dropped 1 unit, but survival was 100%. With 0.5–6 h of anoxia exposure the live adults maintained low but constant ATP levels while [K + ] o and pH continued to change. When these animals were returned to normoxia they could restore hemolymph [K + ] o and subsequent movement. However, with longer durations of anoxia, ATP levels decreased and [K + ] o rose further, and both of these variables correlated tightly with decreased survival. This response contrasts with the anoxia‐sensitive larval stage (LT50: ~1 h). During anoxia larvae attempt escape for up to 30 min and after two hours of anoxia, ATP was <1% of resting, hemolymph [K + ] o increased by 50%, hemolymph pH fell by 1 unit, and survival was zero. The superior anoxia tolerance of adult D. melanogaster appears to be due to the capacity to maintain a paralytic hypometabolic energy state with low but non‐zero ATP levels, and to be able to tolerate extreme extracellular ionic variability. This study suggests that a focus of research in anoxia‐tolerance should be the mechanisms by which animals can survive and quickly recover from such energetic and ionic conditions. Support or Funding Information Supported by NSF IOS1256745. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .