20.500.12556/RUL-164530 Biološka aktivnost izbranih izolatov aktinomicet iz kraških jam in njihova taksonomska uvrstitev Biological activity of selected Actinomyces isolates from Karst caves and their taxonomical classification Vse večja pojavnost bakterij, odpornih proti antibiotikom, predstavlja veliko grožnjo javnemu zdravstvu, zato je iskanje novih protimikrobnih učinkovin neizogibno. Ekstremofilna okolja, kot so jamski ekosistemi, so vir novih bioaktivnih učinkovin, saj tam običajno bivajo še neraziskani mikrobi, ki potencialno producirajo nove biološko aktivne učinkovine. Med njimi imajo aktinobakterije, med katere spadajo aktinomicete, največji potencial. Tehnologije za sekvenciranje celotnega genoma in bioinformatska orodja so razkrili, da aktinobakterije v svojem genomu nosijo zapise za številne gruče biosinteznih genov (GBG), ki se lahko v standardnih laboratorijskih pogojih gojenja ne izražajo (ostanejo tihe). S spreminjanjem pogojev gojenja, v našem primeru sestave gojišča, smo 37 izoliranih aktinomicetnih sevov (izbranih na podlagi morfoloških lastnosti in sposobnosti rasti v različnih gojiščih) spodbudili k proizvodnji protimikrobnih spojin. Gojili smo jih v šestih različnih produkcijskih gojiščih, iz katerih smo pripravili ekstrakt sekundarnih metabolitov. Sledilo je testiranje njihove protimikrobne aktivnosti proti bakterijam Micrococcus luteus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, ter glivam Saccharomyces cerevisiae in Candida albicans. Pri 27 (73 %) ekstraktih smo zaznali protibakterijsko in/ali protiglivno delovanje. Aktinomicetne seve taksonomsko uvrstili na podlagi nukleotidnega zaporedja gena za 16S rRNK v rod Streptomyces. V zadnjem koraku smo z rudarjenjem genoma analizirali biosintetski potencial dveh izbranih sevov. Bioinformacijska analiza z AntiSMASH orodjem je pokazala, da genoma obeh sevov nosita zapis za nekatere znane spojine, vendar predvidene spojine domnevnih GBG kodirajo gene za biosintezo še nepoznanih sekundarnih metabolitov. The increasing prevalence of antibiotic-resistant bacteria poses a significant threat to public health. Therefore, the search for new antimicrobial agents is an imperative. Unique environments, such as cave ecosystems are sources of novel microbes producing bioactive compounds considering that they usually harbor unknown microorganisms potentialy producin novel natural products. Among these, actinobacteria, including actinomycetes, have the greatest potential. Rapid advances of a whole genome sequencing has uncovered that actinobacteria carry numerous silent biosynthetic gene clusters (BGC) in their genomes, that can remain inactive under standard laboratory conditions. In the scope of our study, we have evaluated the impact of media composition and growth conditions of 37 isolated actinomycete (selected based on morphological characteristics and their ability to grow in different media) on the production of secondary metabolites. We cultivated them in six different production media, from which we prepared extracts of secondary metabolites. Subsequently, we tested the antimicrobial activity of these secondary metabolite extracts against Micrococcus luteus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and the fungi Saccharomyces cerevisiae and Candida albicans. Antibacterial and/or antifungal activity was observed in 27 (73%) of the extracts. Furthermore, we taxonomically classified actinomycete strains based on 16S rRNA gene sequence. Through this analysis, all actinomycete strains could be assigned to the genus Streptomyces. Finally, we used genome mining, to demonstrate the biosynthetFic potential of two selected strains. Bioinformatic analysis using the AntiSMASH tool revealed that the genomes of both strains carry a number of known metabolites. However, much larger number of putative BGCs encode genes for the biosynthesis of structuraly unknown secondary metabolites. aktinomicete slovenske kraške jame parametri gojenja protimikrobna aktivnost taksonomska uvrstitev gruče biosinteznih genov sekundarni metaboliti bioinformacijska analiza actinomycetes Slovenian karst caves cultivation parameters antimicrobial activity taxonomic classification biosynthetic gene clusters secondary metabolites bioinformatic analysis true false false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2024-10-30 07:16:29 2024-10-30 07:16:38 2024-11-22 14:54:43 0000-00-00 00:00:00 2024 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 254211 213398531 44908.pdf 44908.pdf 1 785C0E57F299A7DB37D2BA749C28EABB 12d0c9ee41aa95e56ea91faf4726825d4045c9cc55c61801750ffa55c1b91d60 343e8f8e-9686-11ef-b232-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=195023 Biotehniška fakulteta 0 0 0