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FCT1-Teses

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Browsing FCT1-Teses by advisor "Acinas, Silvia G."

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  • Diversity of cultured heterotrophic bacteria from polar sea waters and sea ice ecosystems: A unique source for blue biotechnology
    Publication . Tinto, Eleonora; Power, Deborah M.; Acinas, Silvia G.
    The discovery of the CRISPR-Cas system, a prokaryotic defense mechanism, has revolutionized genomics and biotechnology. This system uses Cas nucleases to precisely cut DNA sequences by relying on a protospacer adjacent motif (PAM). Cas9, especially SpCas9 from Streptococcus pyogenes, has been widely studied for genome engineering due to its wellunderstood biochemistry and short PAM sequence. However, its limitations in the recognition of PAM sequences have led researchers to look for natural orthologs of Cas9. This study focuses on the remote areas of the polar regions, where extreme conditions result in unique environments. During three expeditions - PI-ICE (2019) and ANTOM-2 (2022) in Antarctica, and QikIce in the Arctic (2023) – seawater, sea ice and brine samples were collected. Subsequent cultivation showed differences in bacterial growth and taxa enrichment between seawater and sea ice heterotrophic bacteria. Furthermore, the taxonomic analysis of 199 colonies revealed similarities and variations in their biodiversity across habitats, depths and regions. In particular, in ANTOM-2, seawater samples from different depths showed a prevalence of Gammaproteobacteria in deeper layers, while Alphaproteobacteria dominated the photic zones. Dominant genera included Sulfitobacter, Pseudoalteromonas and Shewanella. Five out of seven deep-sea genera were found in photic zones, including Bacillus, Pseudoalteromonas, Pseudomonas, Psychroserpens and Winogradskyella. In contrast, sea ice isolates from PI-ICE showed an absence of Alphaproteobacteria, with Flavobacteriia and Gammaproteobacteria dominating. Notable genera were Flavobacterium, Psychrobacter and Chryseobacterium. During the QikIce expedition, Bacilli and Flavobacteriia were predominant, while three genera differed from those found in Antarctica: Planomicrobium, Maribacter and Octadecabacter. In the final phase of the study, the design of two primer pairs led to the amplification of potential Cas9 sequences from three Flavobacterium isolates, opening up new avenues for future efforts. This research highlights the importance of exploring extreme environments, such as polar regions, for biotechnological discoveries and expanding the CRISPR-Cas toolbox.
    2023-12-01Master thesis Open access Show more