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008 210830s2020 xx sbm 000 0 eng d
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035 (MiAaPQ)AAI28022910
040 MiAaPQ|beng|cMiAaPQ|dNTU
100 1 Haney, Allissa Marie
245 10 Light and Life; Light-Dependent DNA Processes in Marine
Cyanobacteria
264 0 |c2020
300 1 online resource (226 pages)
336 text|btxt|2rdacontent
337 computer|bc|2rdamedia
338 online resource|bcr|2rdacarrier
500 Source: Dissertations Abstracts International, Volume: 82-
03, Section: B
500 Advisor: Bauer, Carl;Hangarter, Roger P
502 Thesis (Ph.D.)--Indiana University, 2020
504 Includes bibliographical references
520 Marine Synechococcus are a group of globally widespread
and ecologically significant cyanobacteria that live in
widely varying light conditions of oceanic waters.
Cyanobacteria are photosynthetic organisms, and
consequently their survival is restricted to the upper
photic zone of the water column that is penetrated by
light wavelengths to varying depths. Higher energy
wavelengths penetrate the deepest with the exception of
ultraviolet (UV) radiation that scatters through the water
column not penetrating as deep as blue light. Lower energy
red-shifted wavelengths are attenuated close to the
surface. As is true of most cyanobacteria, marine
Synechococcus have developed strategies to utilize the
available light for efficient photosynthesis as well as
for the repair of DNA damaged by UV radiation exposure.I
have discovered that Synechococcus RS9916 (9916) can
repair UV-induced DNA damage in a light-dependent manner,
and that its genome encodes multiple distinct photolyase
enzymes that can repair UV-induced DNA damage. Photolyases
are enzymes that use the energy from blue light to repair
the abnormal bonds formed between adjacent pyrimidine
dimers. All currently analyzed marine Synechococcus
strains and high-light Prochlorococcus ecotypes contain
multiple photolyase genes, leading me to hypothesize this
is a widely used DNA repair strategy for cyanobacteria
living in UV-rich marine waters.RS9916 is also capable of
undergoing chromatic acclimation, a process by which the
light-harvesting photosynthetic antenna pigments can be
changed to maximize the use of the wavelengths of light
that are most abundant in the immediate environment.
Chromatic acclimation offers cyanobacteria a survival
advantage in fluctuating light environments as compared to
similar organisms that cannot undergo chromatic
acclimation. RS9916 Type IV chromatic acclimation is
mediated by genes encoded within a small five kb genomic
island. My research demonstrates that a short 165-bp gene
on this genomic island, fciC, encodes a small protein that
is essential for the transcriptional regulation of this
process. I found that when blue light is more abundant
than green light, FciA upregulates fciC, which then allows
FciC to serially upregulate the transcription of two other
genes encoded on the genomic island that are responsible
for the changes to the chromophore composition of newly
made phycobilisomes. We are now beginning to understand
how Type IV Chromatic Acclimation is regulated in marine
cyanobacteria
533 Electronic reproduction.|bAnn Arbor, Mich. :|cProQuest,
|d2021
538 Mode of access: World Wide Web
650 4 Biochemistry
650 4 Microbiology
650 4 Genetics
653 Chromatic acclimation
653 DNA processes
653 Light regulation
653 Marine cyanobacteria
653 Photolyase
653 Synechococcus
655 7 Electronic books.|2local
690 0487
690 0410
690 0369
710 2 ProQuest Information and Learning Co
710 2 Indiana University.|bBiochemistry
773 0 |tDissertations Abstracts International|g82-03B
856 40 |uhttp://pqdd.sinica.edu.tw/twdaoapp/servlet/
advanced?query=28022910|zclick for full text (PQDT)
912 圖書館PQDT110|b1110406
