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Quorum sensing in the cyanobacterium Gloeothece PCC 6909. / Dilara Islam Sharif

Swansea University Author: Dilara Islam Sharif

Abstract

The thesis sought to study whether cyanobacteria utilise the process of quorum sensing during their growth, to identify any quorum sensing molecules produced by the cyanobacteria Gloeothece PCC 6909/1 and to study the effect of any such molecules in aexenic cultures of the organism. The study presen...

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Published: 2008
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
URI: https://cronfa.swan.ac.uk/Record/cronfa42295
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last_indexed 2018-08-03T10:09:46Z
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spelling 2018-08-02T16:24:28.7293887 v2 42295 2018-08-02 Quorum sensing in the cyanobacterium Gloeothece PCC 6909. 2e29e0943df9157c4a78a9b0d7143592 NULL Dilara Islam Sharif Dilara Islam Sharif true true 2018-08-02 The thesis sought to study whether cyanobacteria utilise the process of quorum sensing during their growth, to identify any quorum sensing molecules produced by the cyanobacteria Gloeothece PCC 6909/1 and to study the effect of any such molecules in aexenic cultures of the organism. The study presents the first evidence of N-octanoyl homoserine lactone (C8-HSL) quorum sensing molecule from axenic cultures of the cyanobacterium PCC 6909 and its sheathless mutant PCC 6909/1 and that the production of this molecule followed a density dependent accumulation, a common feature of many quorum sensing systems. The response of the Gloeothece proteome to exogenous concentrations of C8-HSL was examined, indicating changes in 43 protein spots on a 2D-PAGE gel, thereby indicating a response through global changes in protein expression. Among the 15 proteins that showed more than 2 fold expression changes, RuBisCo, glutamate synthase, chorismate synthase, a LysR family of transcriptional regulator (all up regulated) enolase and aldolase (down regulated) could be identified. A number of phosphorylated proteins also showed increased accumulation suggesting changes in the phosphoproteome of Gloeothece. A response to C8-HSL was also detected in physiological changes of the organism through decreased accumulation of extracellular soluble carbohydrates and an increased acid phosphatase activity from cell extracts. In conclusion, this study presents evidence that the cyanobacterium Gloeothece employs a C8-HSL based quorum sensing system through the accumulation and response to a C8-HSL signal. These findings can help increase our understanding of how colonial cyanobacteria encounter stress at high cell densities. E-Thesis Biochemistry.;Microbiology. 31 12 2008 2008-12-31 COLLEGE NANME Biosciences COLLEGE CODE Swansea University Doctoral Ph.D 2018-08-02T16:24:28.7293887 2018-08-02T16:24:28.7293887 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Biosciences Dilara Islam Sharif NULL 1 0042295-02082018162443.pdf 10798003.pdf 2018-08-02T16:24:43.2700000 Output 20247260 application/pdf E-Thesis true 2018-08-02T16:24:43.2700000 false
title Quorum sensing in the cyanobacterium Gloeothece PCC 6909.
spellingShingle Quorum sensing in the cyanobacterium Gloeothece PCC 6909.
Dilara Islam Sharif
title_short Quorum sensing in the cyanobacterium Gloeothece PCC 6909.
title_full Quorum sensing in the cyanobacterium Gloeothece PCC 6909.
title_fullStr Quorum sensing in the cyanobacterium Gloeothece PCC 6909.
title_full_unstemmed Quorum sensing in the cyanobacterium Gloeothece PCC 6909.
title_sort Quorum sensing in the cyanobacterium Gloeothece PCC 6909.
author_id_str_mv 2e29e0943df9157c4a78a9b0d7143592
author_id_fullname_str_mv 2e29e0943df9157c4a78a9b0d7143592_***_Dilara Islam Sharif
author Dilara Islam Sharif
author2 Dilara Islam Sharif
format E-Thesis
publishDate 2008
institution Swansea University
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Biosciences, Geography and Physics - Biosciences{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Biosciences, Geography and Physics - Biosciences
document_store_str 1
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description The thesis sought to study whether cyanobacteria utilise the process of quorum sensing during their growth, to identify any quorum sensing molecules produced by the cyanobacteria Gloeothece PCC 6909/1 and to study the effect of any such molecules in aexenic cultures of the organism. The study presents the first evidence of N-octanoyl homoserine lactone (C8-HSL) quorum sensing molecule from axenic cultures of the cyanobacterium PCC 6909 and its sheathless mutant PCC 6909/1 and that the production of this molecule followed a density dependent accumulation, a common feature of many quorum sensing systems. The response of the Gloeothece proteome to exogenous concentrations of C8-HSL was examined, indicating changes in 43 protein spots on a 2D-PAGE gel, thereby indicating a response through global changes in protein expression. Among the 15 proteins that showed more than 2 fold expression changes, RuBisCo, glutamate synthase, chorismate synthase, a LysR family of transcriptional regulator (all up regulated) enolase and aldolase (down regulated) could be identified. A number of phosphorylated proteins also showed increased accumulation suggesting changes in the phosphoproteome of Gloeothece. A response to C8-HSL was also detected in physiological changes of the organism through decreased accumulation of extracellular soluble carbohydrates and an increased acid phosphatase activity from cell extracts. In conclusion, this study presents evidence that the cyanobacterium Gloeothece employs a C8-HSL based quorum sensing system through the accumulation and response to a C8-HSL signal. These findings can help increase our understanding of how colonial cyanobacteria encounter stress at high cell densities.
published_date 2008-12-31T03:52:41Z
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score 11.0133505

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