Phylogenetics, cell biology, genomics, and biotechnological applications of Amoebozoa with emphasis on testate amoebae (Arcellinida)

Author(s)

Alfredo Leonardo Porfirio de Sousa

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2024-09-17

Examining board members

Daniel José Galafasse Lahr; Mariana Cabral de Oliveira; Susannah Porter; Lucile Maria Floeter Winter

• Advisor: Daniel José Galafasse Lahr

Abstract

Amoebozoa has emerged as a strategic model group in protistology and evolutionary biology. This eukaryotic group primarily comprises amoeboid organisms (amoebae) with morphologically dynamic cell types that move and/or feed using transient extensions called pseudopodia. The diversity of Amoebozoa spans at least 1.2 billion years of evolutionary history, as estimated by molecular clocks. Being such an ancient lineage, Amoebozoa has presumably witnessed significant geological and biological events, including the formation and fragmentation of three supercontinents, the shaping of Earth\'s current continents and oceans, and major life-extinction events, such as those related to the Cryogenian Sturtian and Marinoan glaciations, often referred to as Snowball Earth.Also, Amoebozoa boasts one of the oldest fossil records assigned to an extant group of organisms: Tonian vase-shaped microfossils (VSMs) linked to testate amoebae (Arcellinida), providing compelling evidence of its ancient origins and evolutionary history. This remarkable diversity, deep evolutionary roots, and rich fossil record make Amoebozoa a fascinating group for illuminating patterns of life evolution. This thesis explores Amoebozoas potential as an emerging model group, with a special focus on the testate amoebae (Arcellinida) group. We delved into Amoebozoa\'s profound evolutionary history through phylogenomics and fossil evidence to gain insights into the evolution of life over geological time. We also studied the evolution of the Rab GTPase gene family within Amoebozoa, highlighting its role in cellular complexity and adaptation. Additionally, we explored methodological advancements by optimizing protocols for actin staining and transient expression of target genes fused to a Green Fluorescent Protein (GFP) marker using Arcellinida as a model. Furthermore, the thesis includes the generation of a draft genome for Cryptodifflugia operculata (Arcellinida: Amoebozoa). Finally, we also explore potential biotechnological applications arising from testate amoebaes diverse morphological traits. Through a comprehensive multidisciplinary approach, this thesis underscores Amoebozoas potential to advance biological knowledge and potential technological innovations. Ultimately, we emphasize the importance of establishing and studying model groups like Amoebozoa to broaden our understanding of fundamental biological principles beyond those provided by single-species model organisms. (AU)

• FAPESP's process: 19/22692-8 - Shedding light on the molecular apparatus of the shell formation process in testate amoeba (Amoebozoa:Arcellinida)
• Grantee: Alfredo Leonardo Porfirio de Sousa
• Support Opportunities: Scholarships in Brazil - Doctorate