Molecular bases and evolutionary constraints of cellular acid tolerance in cyanobacteria and invertebrates subjected to ocean acidification and other sources of stress (METASTRESS)

• Main Author: Simonetti, Silvia
• Other Authors: CORSI, ILARIA
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Università degli Studi di Siena 2024
• Subjects: Ocean acidification; ABC protein transporters; Tolerance to acid stress; Polychaeta; Cyanobacteria; Ischia CO2 vents; Settore BIO/07 - Ecologia
• Online Access: https://hdl.handle.net/11365/1262117

The ongoing decreasing surface pH that seas and oceans are facing is termed ocean acidification (OA). The primary reason for this phenomenon is the emission of carbon dioxide (CO2) into the atmosphere from human activities, like the burning of fossil fuels, which has drastically increased since the industrial revolution, reaching higher levels during these decades. This environmental risk is considered among the most hazardous threats to marine ecosystems associated with global change and severely affects marine life worldwide. Responses of marine species to acidified seawaters have been deeply studied and adverse effects at different levels, from single species up to whole communities, have been pointed out. Although OA is clearly posing a threat to marine life, some species have demonstrated the ability to tolerate and thrive in such conditions. Information on the mechanisms driving the tolerance of adapted species to decrease seawater pH is limited, and new knowledge may be obtained from species inhabiting sites with naturally low pH, such as the volcanic CO2 system off the Castello Aragonese on the Ischia Island (Italy). Understanding the molecular mechanisms of adaptation enabling marine species to tolerate a lowered seawater pH could support predictions of the consequences of future OA scenarios for marine life. Growing evidence of the involvement of ABC transport proteins in resistance towards acid stress in bacteria and tumor cell lines has been demonstrated. Researchers have suggested that the tolerance to this kind of stress is due to the transport of substances that contribute to the maintenance of internal cell homeostasis carried out by the ABC proteins. Here, we aimed at elucidating the involvement of ABC transport proteins in tolerance to low-pH/high-pCO2 environments, by investigating their gene regulation, in species of marine microorganisms and metazoans considered tolerant to acidified environments. Halomicronema metazoicum is a marine filamentous cyanobacterium able to cope with hostile ...