QsrB mediated repression of quorum sensing in Clostridium acetobutylicum ATCC 824
The Gram-positive obligate anaerobe Clostridium acetobutylicum is recognised for its ability to metabolise sugars into organic acids and solvents, particularly the biofuel butanol. It is also a model organism for clostridial spore formation, controlled by the master regulator Spo0A. C. acetobuty...
| Main Author: | |
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| Format: | Thesis (University of Nottingham only) |
| Language: | English |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://eprints.nottingham.ac.uk/77193/ |
| _version_ | 1848800972869992448 |
|---|---|
| author | Daike, Temiloluwa |
| author_facet | Daike, Temiloluwa |
| author_sort | Daike, Temiloluwa |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | The Gram-positive obligate anaerobe Clostridium acetobutylicum is
recognised for its ability to metabolise sugars into organic acids and
solvents, particularly the biofuel butanol. It is also a model organism for
clostridial spore formation, controlled by the master regulator Spo0A.
C. acetobutylicum has been historically used for industrial-scale
production of organic solvents like acetone and butanol however
improvements are required for a viable economic process. Signalling
peptide-based regulation of solvent formation and sporulation in
C. acetobutylicum ATCC 824 has been recognised and a regulatory role
for the RRNPP-type Quorum sensing system B (QssB) comprising
Quorum sensing regulator B (QsrB) and its cognate signalling peptide
Quorum sensing peptide B (QspB) has been established.
The aims of this PhD study were threefold: (i) to establish diversity and
distribution of RRNPP-type systems in the genus Clostridium, and in
particular those similar to QssB; (ii) to better understand how QssB
interlinks with the known Spo0A regulatory network and to establish
which genes it controls; and (iii) establish the sequence of the mature
QspB-derived signalling peptide.
Using a bioinformatics approach, RRNPP-type quorum sensing systems
were identified in 15 clostridial species and 112 strains in this category,
accounting for approximately 25% of the currently sequenced species of
the genus Clostridium sensu stricto. Of these, only 2 species and 16
strains contained a close homolog of the QssB system.
A transcriptomic comparison was undertaken between the
C. acetobutylicum ATCC 824 WT and its qsrB overexpressing derivative.
The latter had previously been shown to be considerably reduced in
solvent and endospore formation, a phenotype that was reproduced here
before RNA sequencing analysis commenced. The study
transcriptomically validated the observed phenotype of reduced solvent
formation and sporulation with a downregulation in genes involved in
solvent formation - adhE1, ctfA and ctfB. Noteworthy was the discovery
that despite the reduction in spore formation by the overexpression of
qsrB, QsrB did not appear to directly regulate the expression of spo0A
but rather reduced the expression of sporulation-specific sigma factors
and other genes controlled by Spo0A.
RRNPP-type quorum sensing peptides of the Qss system of
C. acetobutylicum were experimentally identified in culture supernatant
in this study. 6 heptapeptides deriving from the C-terminal part of
previously predicted C. acetobutylicum quorum sensing peptides could
be identified in spent culture supernatants. For QssB it was confirmed
that the QspB-derived mature signalling peptide consists of the sequence
AEPTWGW.
Future work may focus on establishing direct target genes for the QssB
system, precise mode of action, as well as establishing the proteases and
transporters involved in peptide maturation and uptake. |
| first_indexed | 2025-11-14T21:00:03Z |
| format | Thesis (University of Nottingham only) |
| id | nottingham-77193 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T21:00:03Z |
| publishDate | 2024 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-771932024-07-19T07:52:06Z https://eprints.nottingham.ac.uk/77193/ QsrB mediated repression of quorum sensing in Clostridium acetobutylicum ATCC 824 Daike, Temiloluwa The Gram-positive obligate anaerobe Clostridium acetobutylicum is recognised for its ability to metabolise sugars into organic acids and solvents, particularly the biofuel butanol. It is also a model organism for clostridial spore formation, controlled by the master regulator Spo0A. C. acetobutylicum has been historically used for industrial-scale production of organic solvents like acetone and butanol however improvements are required for a viable economic process. Signalling peptide-based regulation of solvent formation and sporulation in C. acetobutylicum ATCC 824 has been recognised and a regulatory role for the RRNPP-type Quorum sensing system B (QssB) comprising Quorum sensing regulator B (QsrB) and its cognate signalling peptide Quorum sensing peptide B (QspB) has been established. The aims of this PhD study were threefold: (i) to establish diversity and distribution of RRNPP-type systems in the genus Clostridium, and in particular those similar to QssB; (ii) to better understand how QssB interlinks with the known Spo0A regulatory network and to establish which genes it controls; and (iii) establish the sequence of the mature QspB-derived signalling peptide. Using a bioinformatics approach, RRNPP-type quorum sensing systems were identified in 15 clostridial species and 112 strains in this category, accounting for approximately 25% of the currently sequenced species of the genus Clostridium sensu stricto. Of these, only 2 species and 16 strains contained a close homolog of the QssB system. A transcriptomic comparison was undertaken between the C. acetobutylicum ATCC 824 WT and its qsrB overexpressing derivative. The latter had previously been shown to be considerably reduced in solvent and endospore formation, a phenotype that was reproduced here before RNA sequencing analysis commenced. The study transcriptomically validated the observed phenotype of reduced solvent formation and sporulation with a downregulation in genes involved in solvent formation - adhE1, ctfA and ctfB. Noteworthy was the discovery that despite the reduction in spore formation by the overexpression of qsrB, QsrB did not appear to directly regulate the expression of spo0A but rather reduced the expression of sporulation-specific sigma factors and other genes controlled by Spo0A. RRNPP-type quorum sensing peptides of the Qss system of C. acetobutylicum were experimentally identified in culture supernatant in this study. 6 heptapeptides deriving from the C-terminal part of previously predicted C. acetobutylicum quorum sensing peptides could be identified in spent culture supernatants. For QssB it was confirmed that the QspB-derived mature signalling peptide consists of the sequence AEPTWGW. Future work may focus on establishing direct target genes for the QssB system, precise mode of action, as well as establishing the proteases and transporters involved in peptide maturation and uptake. 2024-07-16 Thesis (University of Nottingham only) NonPeerReviewed application/pdf en cc_by https://eprints.nottingham.ac.uk/77193/1/DAIKE_Temiloluwa_Thesis%20Jan24.pdf Daike, Temiloluwa (2024) QsrB mediated repression of quorum sensing in Clostridium acetobutylicum ATCC 824. PhD thesis, University of Nottingham. Clostridium acetobutylicum quorum sensing ABE fermentation QsrB QspB signalling peptides |
| spellingShingle | Clostridium acetobutylicum quorum sensing ABE fermentation QsrB QspB signalling peptides Daike, Temiloluwa QsrB mediated repression of quorum sensing in Clostridium acetobutylicum ATCC 824 |
| title | QsrB mediated repression of quorum sensing in Clostridium acetobutylicum ATCC 824 |
| title_full | QsrB mediated repression of quorum sensing in Clostridium acetobutylicum ATCC 824 |
| title_fullStr | QsrB mediated repression of quorum sensing in Clostridium acetobutylicum ATCC 824 |
| title_full_unstemmed | QsrB mediated repression of quorum sensing in Clostridium acetobutylicum ATCC 824 |
| title_short | QsrB mediated repression of quorum sensing in Clostridium acetobutylicum ATCC 824 |
| title_sort | qsrb mediated repression of quorum sensing in clostridium acetobutylicum atcc 824 |
| topic | Clostridium acetobutylicum quorum sensing ABE fermentation QsrB QspB signalling peptides |
| url | https://eprints.nottingham.ac.uk/77193/ |