Increased acidification/PCO2 of sea water is a threat to the environment and affects marine animals’ homeostasis. In this study, the effect of sea water pH changes was assessed on the stinging cells, nematocytes, of jellyfish (Cnidarians’ Scyphozoan) collected in the Strait of Messina, Italy, which possess venom containing nematocysts. Two features were studied: 1) regulatory volume decrease (RVD), a homeostatic parameter common to all cells, in nematocytes, and 2) nematocyst discharge with release of toxins, used for Cnidarians’ defense and aggression strategies. To test the effect of pH on RVD, nematocytes were isolated with 605mM NaSCN and subjected to 35% hyposmotic stress in artificial sea water (ASW), at normal (7.65) or acid pH (4.5). Untreated nematocytes, after their expected swelling, regulated their volume within 15 min by activating K+ and Cl- channels and cotransporters, whereas RVD was abrogated at pH 4.5, indicating a pH-dependence. Nematocyst discharge was assessed in acid ASW (pH 4.5) plus 1% trypsin. Under these conditions, and in contrast to normal pH, no discharge response was observed. In conclusion, these data indicate that Cnidarians’ homeostasis and function may be altered by environmental changes, such as sea water acidification, validating jellyfish as a bioindicator for marine environmental quality monitoring.

Sea water acidification alters cell volume regulation and discharge in jellyfish.

MARINO, Angela;MORABITO, Rossana;LA SPADA, Giuseppa;
2012-01-01

Abstract

Increased acidification/PCO2 of sea water is a threat to the environment and affects marine animals’ homeostasis. In this study, the effect of sea water pH changes was assessed on the stinging cells, nematocytes, of jellyfish (Cnidarians’ Scyphozoan) collected in the Strait of Messina, Italy, which possess venom containing nematocysts. Two features were studied: 1) regulatory volume decrease (RVD), a homeostatic parameter common to all cells, in nematocytes, and 2) nematocyst discharge with release of toxins, used for Cnidarians’ defense and aggression strategies. To test the effect of pH on RVD, nematocytes were isolated with 605mM NaSCN and subjected to 35% hyposmotic stress in artificial sea water (ASW), at normal (7.65) or acid pH (4.5). Untreated nematocytes, after their expected swelling, regulated their volume within 15 min by activating K+ and Cl- channels and cotransporters, whereas RVD was abrogated at pH 4.5, indicating a pH-dependence. Nematocyst discharge was assessed in acid ASW (pH 4.5) plus 1% trypsin. Under these conditions, and in contrast to normal pH, no discharge response was observed. In conclusion, these data indicate that Cnidarians’ homeostasis and function may be altered by environmental changes, such as sea water acidification, validating jellyfish as a bioindicator for marine environmental quality monitoring.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/1954287
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