The physiological and molecular response of Aurelia sp.1 under hypoxia

Abstract

Few studies have been published on the mechanisms of hypoxia response and tolerance in jellyfish, especially with respect to the regulatory mechanism at the molecular level. In this study, Aurelia sp.1, which is frequently found in Chinese coastal waters, was cultivated in a hypoxic system to determine the molecular mechanisms underlying its hypoxic response by studying the physiological activity, gene expression and metabolite contents in the prolyl hydroxylase domain (PHD)-hypoxia inducible factor (HIF) oxygen-sensing system. Physiological activity; the expression of PHD, HIF, ALDO (fructose-bisphosphate aldolase), PDK (pyruvate dehydrogenase kinase), and LDH (lactate dehydrogenase) genes; and the lactic acid content in medusae were significantly affected by hypoxia. The up-regulation of ALDO, PDK and LDH, which was directly or indirectly induced by HIF, mediated the transition from aerobic respiration to anaerobic glycolysis in the medusae. In polyps, there was a slight increase in the expression of HIF, PHD and ALDO, no obvious change in that of PDK and a slight decrease in that of LDH throughout the experiment; however, these changes were insufficient to induce the shift. This study provides a scientific basis for elucidating the regulatory mechanism underlying the PHD-HIF oxygen-sensing system in Aurelia sp.1.

Figure 1

The dissolved oxygen concentration range.

Figure 2

The variation of bell contraction number per minute in medusa.

Figure 3

The gene expression variation of HIF in medusa and polyps over time (*represents p < 0.05 and **represents p < 0.01; Error bar is standard error).

Figure 4

The gene expression variation of PHD in medusa and polyps over time (*represents p < 0.05 and **represents p < 0.01; Error bar is standard error).

Figure 5

The gene expression variation of ALDO in medusa and polyps over time (*represents p < 0.05 and **represents p < 0.01; Error bar is standard error).

Figure 6

The gene expression variation of PDK in medusa and polyps over time (*represents p < 0.05 and **represents p < 0.01; Error bar is standard error).

Figure 7

The gene expression variation of LDH in medusa and polyps over time (*represents p < 0.05 and **represents p < 0.01; Error bar is standard error).

Figure 8

The variation of lactic acid content in medusa over time (*represents p < 0.05 and **represents p < 0.01; Error bar is standard error).

Figure 9

Correlation analysis of related gene expression in medusa.

Figure 10

Correlation analysis of related gene expression in polyps.

Figure 11

The partial regulation pathway of HIF (STAT3:signal transducer activator of transcription 3; NF-κB: nuclear factor κB; PHD: prolyl hydroxylase domains; HIF: hypoxia inducible factor; ALDO: fructose-biphosphate aldolase; PDK: pyruvate dehydrogenase kinase; LDH: lactate dehydrogenase; PDH: pyruvate dehydrogenase; G3P: glyceraldehyde 3-phosphate; GLUT: glucose transporter).