20.500.12556/RUL-186544 Dinamika specifičnih bakterijskih populacij v različnih fazah rasti diatomejske kulture, okužene z virusom Dynamics of specific bacterial populations at different growth stages of a virus-infected diatom culture Diatomejski virusi so pomemben dejavnik celične lize diatomej in s tem povezanega sproščanja različnih organskih snovi v okolje. Virusi z okužbo gostiteljskih celic posredno vplivajo na sestavo in dinamiko mikrobnih združb, ki se nahajajo v okolju diatomej ali so z njimi v neposrednem stiku. Take interakcije še niso povsem raziskane in njihovo poznavanje bi omogočilo celovitejši vpogled v kroženje ogljika v morskih sistemih ter vpliv virusov na razne ekološke pojave, kot so fitoplanktonski razrasti. V naši raziskavi smo želeli ugotoviti, kako diatomejski virus PnGalRNAV tipa II vpliva na diatomejsko kulturo Pseudo-nitzschia galaxiae in z njo povezano mikrobno združbo prostoživečih in na fikosfero in detritosfero pritrjenih mikrobov ter kako se v času okužbe spreminja njihova dinamika. Ugotovili smo, da virusna okužba pospeši propad diatomej, kar ima vpliv na zgradbo mikrobne populacije, saj se številčnost mikrobov poveča, predvsem v številu prostoživečih mikrobov. Z metodo Fluorescence in situ hybridization in mikroskopskim pristopom smo ugotovili, da se spreminja dinamika alfaproteobakterij, gamaproteobakterij in bakteroidet, pri čemer so bakteroidete zaradi svoje sposobnosti razgradnje kompleksnih polisaharidov, prevladovale v vseh treh frakcijah. Naši rezultati kažejo, da okužba s PnGalRNAV tipa II ne vpliva le na P. galaxiae, ampak posredno vpliva tudi na sestavo in dinamiko mikrobne združbe. S tem lahko virusna okužba te vrste diatomej posredno vpliva na del kroženja organske snovi in ogljika v morskih in oceanskih ekosistemih. Diatom viruses are an important driver of diatom cell lysis and the associated release of various organic compounds into the environment. By infecting host cells, viruses indirectly influence the composition and dynamics of microbial communities that inhibit the vicinity of diatoms or are directly associated with them. These interactions remain poorly understood, despite their potential importance for understanding carbon cycling in marine ecosystems and their role in ecological processes such as phytoplankton blooms. In this study we investigated how the diatom-infecting virus PnGalRNAV type II affects cultures of Pseudo-nitzschia galaxiae and the associated microbial community, including free-living and particle-associated microorganisms in the phycosphere and detritosphere. We also examined how the dynamics of these microbial fractions change during viral infection. Our results showed that viral infection accelerates the demise of the diatom population and alters microbial community structure by increasing microbial abundance, particularly within the free-living fraction. Using a Fluorescence in situ hybridization protocol combined with epifluorescent microscopy, we observed shifts in the dynamics of Alphaproteobacteria, Gammaproteobacteria and Bacteroidota, with Bacteroidota becoming the dominant group across all three fractions, likely due to their ability to degrade complex polysaccharides. Our findings demonstrate that infection by PnGalRNAV type II affects not only P. galaxiae itself but also indirectly reshapes the composition and dynamics of the associated microbial community. Consequently, viral infection of this diatom may have an important part in the cycling of the organic matter and carbon in marine ecosystems. diatomejski virusi PnGalRNAV tip II Pseudo-nitzschia galaxiae biološka ogljična črpalka alfaproteobakterije gamaproteobakterije bakteroidete mikrobna združba diatom viruses PnGalRNAV type II Pseudo-nitzschia galaxiae biological carbon pump Alphaproteobacteria Gammaproteobacteria Bacteroidota microbial community true false false [T. Rupnik] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2026-09-03 07:18:00 2026-09-03 07:18:07 2026-09-04 04:30:40 0000-00-00 00:00:00 2026 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 579.26:578:582.261 286705 289851395 60916.pdf 60916.pdf 1 829A0E457686BDCB41EE36D75BF487CF 4dd891fe9ab2f0fc6ee379298e4478a53329124849dc0da5c477bc40f1986938 6a0150ea-a756-11f1-9b0d-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=245815 Biotehniška fakulteta 0 0 0