Show simple item record

dc.contributor.authorHill, Amy
dc.date.accessioned2021-12-16T01:05:33Z
dc.date.available2021-12-16T01:05:33Z
dc.date.submitted2021-08-01
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/331542
dc.description.abstractSerratia sp. ATCC 39006 (S39006) is a Gram-negative, rod-shaped enterobacterium known for the production two antibiotics; the β-lactam, 1-carbapen-2-em-3-carboxylic acid (a carbapenem) and the red-pigmented tripyrrole, 2-methyl-3-pentyl-6-methoxyprodigiosin (prodigiosin; a prodiginine). It also produces plant cell wall degrading enzymes (PCWDEs) and is capable of flagellar-mediated swimming and swarming motility. S39006 is the only enterobacterium known to naturally produce gas vesicles (GVs). GVs are proteinaceous, intracellular organelles that increase the buoyancy of a cell and enable flotation upwards through the water column and colonisation of air-liquid interfaces. The production and regulation of GVs is a complex process with a range of regulatory inputs. GVs are expressed from a cluster of 19 genes arranged in two contiguous operons, gvpA1-gvpY and gvrA-gvrC. Prior to this study, three regulators encoded within the GV cluster, which are essential for GV production, had been described: GvrA, GvrB, and GvrC. Other regulators that have been identified include the post-transcriptional regulator RsmA, the repressor of the ribose operon, RbsR, and the DeoR-family transcriptional regulator, FloR. This study employed random transposon mutagenesis, visual screening of mutant phenotypes, cloning and sequencing, and bioinformatic analysis to identify novel regulators of GV production. This included mutants with transposon insertions in genes encoding an O-antigen ligase (waaL), the sigma factor σ54 (rpoN), and a transcription factor (dksA). The waaL mutant exhibited increased transcription and expression of GV genes but was unable to float. Pleiotropic effects of the transposon insertion included an increase in carbapenem production and a decrease in motility and virulence in a Caenorhabditis elegans model. The rpoN mutant showed a reduction in GV and pectate lyase production, swimming and swarming motility, and an increase in carbapenem production. The dksA mutant showed a decrease in GV and antibiotic production, motility, and virulence in C. elegans. A quantitative proteomic analysis was undertaken comparing the rpoN and dksA mutants against wild type S39006 to understand their regulatory roles. Expression of proteins involved in GV biogenesis, antibiotic production and motility as well as previously identified transcriptional regulators were significantly altered in each mutant, compared to wild type.
dc.description.sponsorshipWoolf Fisher Trust Cambridge Trust
dc.rightsAll Rights Reserved
dc.rights.urihttps://www.rioxx.net/licenses/all-rights-reserved/
dc.subjectSerratia
dc.subjectgas vesicle
dc.subjectcarbapenem
dc.subjectprodigiosin
dc.subjectrpoN
dc.subjectdksA
dc.titleNovel pleiotropic regulators of flotation, secondary metabolite production, and virulence in Serratia sp. ATCC 39006
dc.typeThesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnameDoctor of Philosophy (PhD)
dc.publisher.institutionUniversity of Cambridge
dc.date.updated2021-12-15T07:33:39Z
dc.identifier.doi10.17863/CAM.78996
rioxxterms.licenseref.urihttps://www.rioxx.net/licenses/all-rights-reserved/
dc.contributor.orcidHill, Amy [0000-0003-0897-2798]
rioxxterms.typeThesis
dc.publisher.collegeTrinity
cam.supervisorSalmond, George
cam.depositDate2021-12-15
pubs.licence-identifierapollo-deposit-licence-2-1
pubs.licence-display-nameApollo Repository Deposit Licence Agreement
rioxxterms.freetoread.startdate2022-12-16


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record