Post-graduate theses
Current Record: 33 of 800
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| Identifier |
000454370 |
| Title |
Comparative study of the resistance of microbial strains isolated from extreme environments of the Hellenic Volcanic Arc (Kolumbo, Santorini, Milos) |
| Alternative Title |
Συγκριτική μελέτη της ανθεκτικότητας μικροβιακών στελεχών που απομονώθηκαν από ακραια περιβάλλοντα του Ελληνικού Ηφαιστειακού Τόξου (Κολούμπος, Σαντορίνη, Μήλος) |
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Author
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Ζάκα, Ελευθερία Ι.
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Thesis advisor
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Λαμπαδαρίου, Νικόλαος
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Reviewer
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Πολυμενάκου, Παρασκευή
Μανδαλάκης, Μανώλης
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| Abstract |
Extremophiles may “love” or tolerate extreme conditions (Rothschild & Mancinelli
2001), such as those prevailing in the active Hellenic Volcanic Arc (EHT). At EHT, the
hydrothermal vents of the Santorini-Kolumbo volcanic complex and the Milos island
are of particular interest due to the extreme environmental conditions that prevail such
as high concentrations of CO2 and metals and low pH values. Previous studies have
shown that these areas host an impressive microbial diversity (Oulas et al. 2016,
Christakis et al. 2018), while bacteria of the genus Pseudomonas that were isolated
from the active area of Kolumbo volcano appear to be tolerant to a series of
environmental stressors such as low pH values, high concentrations of heavy metals as
well as of antibiotics (Mandalakis et al. 2019, Bravakos et al. 2021). The purpose of
this work was to isolate microorganisms from the specific hydrothermal vents to check
the presence of resistance genes to a series of antibiotics. Microbial cultures were
performed from samples collected from Santorini caldera, the active area of Kolumbo
volcano and the coastal hydrothermal vents of Milos island. This was followed by
isolation of genomic DNA, as well as amplification and sequencing of the 16S rRNA
genes using the universal set of primers 27f and 1492r. This particular gene is widely
used for the taxonomic identification of microorganisms through the international
GenBank database. Representatives of the Pseudomonadota phylum were found in all
three sampling areas, while bacteria of the Bacillota phylum were isolated from
Santorini caldera and Kolumbo volcano. In Santorini, isolates of the genus Vibrio
prevailed among Pseudomonadota phylum members (63%), while within Bacillota
phylum, isolates closely related to the genus Niallia was the most abundant accounting
for 72% of the total Bacillota members. In Kolumbo, all Pseudomonadota belonged to
the genus Vibrio and among Bacillota, the dominant genus was Cytobacillus covering
44% of the identified strains. Three bacteria of the genus Vibrio were isolated from
Milos. Next step of the study was the investigation of six antibiotic resistance genes
(INT, Sul1, TetA, blaCTX-M, blaOXA-48 and QnrS) using appropriate set of primers (Lazăr
et al. 2021). At least one resistance gene was found in 50% of the bacteria. In Santorini
the most common gene was blaOXA-48 (38%), while in Kolumbo Sul1 prevailed (34%)
with blaOXA-48 occupying a significant percentage (29%). In Milos there was a single
strain carrying the resistance gene blaCTX-M.
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| Language |
English |
| Subject |
Antibiotic resistance |
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Extremophile microorganisms |
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Ακραιόφιλοι μικροοργανισμοί |
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Ανθεκτικότητα στα αντιβιοτικά |
| Issue date |
2023-03-24 |
| Collection
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School/Department--School of Sciences and Engineering--Department of Biology--Post-graduate theses
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Type of Work--Post-graduate theses
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| Permanent Link |
https://elocus.lib.uoc.gr//dlib/b/8/8/metadata-dlib-1678976707-755531-17167.tkl
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| Views |
495 |
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