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@PHDTHESIS{Rackow:1043185,
author = {Rackow, Bente},
title = {{E}lucidation of anti-viral strategies in {S}treptomyces},
volume = {298},
school = {Düsseldorf},
type = {Dissertation},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {FZJ-2025-02793},
series = {Schriften des Forschungszentrums Jülich Reihe
Schlüsseltechnologien / Key Technologies},
pages = {xii, 148},
year = {2025},
note = {Dissertation, Düsseldorf, 2025},
abstract = {Streptomyces species have been highly studied for decades
for their multicellular development and their distinguished
ability to produce a myriad of different bioactive small
molecules. In recent years the interaction between these
multicellular bacteria and their predatory viruses, the
bacteriophages (or phages for short) came into the focus of
research. It was recently discovered that specialized
metabolites produced by Streptomyces not only protect from
competing bacteria but also from phage infections. Both
aminoglycosides and anthracyclines, small molecules produced
by Streptomyces have been shown to efficiently inhibit phage
infection, but the exact mechanism of action remained
elusive. This multi functionality of small molecules piqued
the interest. This work sets out to elucidate suchanti-viral
strategies of Streptomyces and to integrate the chemical
defense mediated by small molecules into the context of the
bacterial immune system. Initially, spent medium of natural
aminoglycoside producing Streptomyces spp. was tested for
its antiphagepotential, showing different degrees of defense
potential, specific to the molecule produced as well as the
phage tested. Extracellular effects of spent medium could
only be determined for phages infecting less related
species, such as Corynebacterium glutamicum. Furthermore,
isolation and characterization of novel Streptomyces phages
broadened the repertoire of phages that can be used to
understand the interaction between host and phage and how
chemical defense affects this interaction. Three of the four
newly isolated phages infect several different species.
These broad host range phages pose to be good tools to
understand also the influence of the host background on the
efficiency of chemical defense. Large screenings of small
molecules mediating chemical defense with two different
collections of phages revealed several sensitivity
determinants of phages to chemical defense and showed that
the efficiency of chemical defense is a delicate process
influenced by a manifold of factors. Streptomyces phages
showed sensitivity towards most of the compounds tested,
whereas coliphages only showed sensitivity towards DNA
intercalating molecules. Redirecting the focus of this work
towards the mechanism of action of the anthracycline
daunorubicin, many insights in the inhibitory effect of this
small molecule were obtained. Daunorubicin acts
intracellularly, after the genome injection of phages but
before DNA replication. The host background influences the
potency of daunorubicin-mediated defense and synergy between
chemical defense and intracellular defense systems could
bedetermined. Even though the direct mechanism of action of
chemical defense remains yet elusive, several important
insights were gained and provide basis for further research
in this area of anti-phage defense.},
cin = {IBG-1},
cid = {I:(DE-Juel1)IBG-1-20101118},
pnm = {2171 - Biological and environmental resources for
sustainable use (POF4-217)},
pid = {G:(DE-HGF)POF4-2171},
typ = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
urn = {urn:nbn:de:0001-2508181047006.380374208525},
doi = {10.34734/FZJ-2025-02793},
url = {https://juser.fz-juelich.de/record/1043185},
}