THESIS
2020
xxii, 207 pages : illustrations (chiefly color) ; 30 cm
Abstract
Deep sea is a harsh environment characterized by high hydrostatic pressure and low
temperatures. For instance, high hydrostatic pressure can disrupt actin organization and
microtubules assembly, which have adverse influences on intracellular movements and
cell motility. Nucleic acids structures can be influenced by not only high hydrostatic
pressure but also cold temperatures. These unfavourable effects caused by the high
hydrostatic pressure and coldness are challenging for deep-sea animals. In addition, there
are chemosynthetic ecosystems, such as hydrothermal vents and hydrocarbon seeps, in
the deep sea. Dense communities of megafauna rely on the nutrients produced by
chemotrophic bacteria that are capable of utilizing chemical substances as energy
resources. To study the po...[
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Deep sea is a harsh environment characterized by high hydrostatic pressure and low
temperatures. For instance, high hydrostatic pressure can disrupt actin organization and
microtubules assembly, which have adverse influences on intracellular movements and
cell motility. Nucleic acids structures can be influenced by not only high hydrostatic
pressure but also cold temperatures. These unfavourable effects caused by the high
hydrostatic pressure and coldness are challenging for deep-sea animals. In addition, there
are chemosynthetic ecosystems, such as hydrothermal vents and hydrocarbon seeps, in
the deep sea. Dense communities of megafauna rely on the nutrients produced by
chemotrophic bacteria that are capable of utilizing chemical substances as energy
resources. To study the potential mechanisms of biological adaptation to deep-sea
environment, we performed genomic analysis of representative species from both deep-sea
non-vent environment and deep-sea chemosynthetic environment, including
Hirondellea gigas amphipod from Challenger Deep in Mariana Trench, Aldrovandia
affinis fish from the Pacific Ocean, Phreagena okutanii clam from a deep-sea
hydrothermal vent, Archivesica marissinica clam from a deep-sea methane seep, and
Gigantopelta aegis gastropod from a hydrothermal vent. Our results suggest that genetic
adaptation to the deep-sea environment are mediated by both gene family expansion and
amino acid substitutions. Furthermore, the vent-endemic megafauna is highly dependent
on the mutualistic relationships with their symbionts. The host provide intermediates to
fulfill the metabolic needs of their endosymbionts, and in return, the symbionts are active to generate nutrients and provide to the hosts through lysis processes. Overall, my thesis
study not only provides high-quality transcriptomes and genomes of a few representative
deep-sea animals for future deep-sea studies but also facilitates a better understanding of
the molecular adaptation to the deep sea.
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