Machado, Henrique

Mikroorganismer isoleret fra jord har i årtier været en kilde til nyeenzymer og kemiske forbindelser, der er blevet produceret af farmaceutiske og bioteknologiske virksomheder og anvendt af mennesker. Der er behov for nye kemiske forbindelser, herunderantibiotika, nye enzymatiske aktiviteter og nye mikroorganismer, der skal anvendes som cellefabrikker til produktion. Vi må derfor tænke i udnyttelse af nye mikrobielle nicher og anvendelse af forskelligestrategier for at sikre en pipeline af nye opdagelser. Forskere er begyndt at udforske andre nicher end jordbunden, og her skiller havmiljøet sig ud som en hidtil under-udforsket niche. Formålet med dette phd-arbejde er at finde ny biodiversitet og ny bioaktivitet i marine bakterier. I arbejdet er anvendt analyse af genomer og gensekvenser på en samling af marine bakterier, der er etableret underGalathea 3 ekspeditionen.Det konkluderes, ved analyse af hel-genom-sekvenser, at det genetiskerepertoire for sekundær metabolit-produktion i disse bakterier er langt større end forventet; dvs som hidtil udforsket med klassisk bioassay-guided fraktionering. Desuden er genomsekvenserne anvendt til at udvikle en ny fylogenetisk markør (fur-genet) til identifikation af medlemmer af Vibrionaceae familien, hvilket har ført til identifikation af to nye arter. Genomerne er minet for potentielt bioaktive stoffer,her nye cytokrom P450 enzymer, der kan anvendes i bioteknologi, og de er klonet og udtrykt i både E. coli og gær. Endelig er komparativ analyse af genomer-sekvenserne anvendt til en større fylogenetisk og genetisk analyse af den marine slægten Photobacterium. Samlet har dette ph.d.-arbejde bidraget til vores forståelse af marine mikroorganismer og deres diversitet, til udvikling af nyeidentifikations-redskaber samt peget på disse organismer som en meget lovende ressource for yderligere bioprospektering.For decades, terrestrial microorganisms have been used as sources of countless enzymes and chemical compounds that have been produced by pharmaceutical and biotech companies and used by mankind. There is a need for new chemical compounds, including antibiotics,new enzymatic activities and new microorganisms to be used as cell factories for production. Therefore exploitation of new microbial niches and use of different strategies is an opportunity to boost discoveries. Even though scientists have started to explore several habitats other than the terrestrial ones, the marine environment stands out as a hitherto under-explored niche. This thesis work uses high-throughput sequencing technologies on a collection of marine bacteria established during the Galathea 3 expedition, with the purpose of unraveling new biodiversity and new bioactivities. Several tools were used for genomic analysis in order to better understand the potential harbored in marine bacteria. The work presented makes use of whole genome sequencing of marine bacteria to prove that the genetic repertoire for secondary metabolite production harbored in these bacteria is far larger than anticipated; to identify and develop a new phylogenetic marker for the identification of members of the Vibrionaceae family, which led to the identification of two new species using this straightforward pipeline;to discovery of new cytochrome P450 enzymes to be used in biotechnology; and to a thorough study of the marine genus Photobacterium, by means of comparative genomics. In conclusion, this PhD thesis has contributed to our understanding of the marine microbial environment by studying genomic information of several marine bacteria, expanding the number of marine species taxonomically described, providing identification tools for further marine species documentation and pointing to these organisms as a very promising resource for further bioprospecting

Online Research Database In Technology

Marine Bacterial Genomics:an ocean of opportunity

http://orbit.dtu.dk/ws/files/125482775/Marine_Bacterial_Genomics.pdf

Marine Bacterial Genomics:an ocean of opportunity

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Online Research Database In Technology