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You searched for subject:(Hypersaline Microbial Mat). Showing records 1 – 2 of 2 total matches.

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University of Connecticut

1. Fowler, Alexandre J. Stromatolitic Knobs in Storrs Lake, San Salvador, Bahamas: Insights into Organomineralization.

Degree: MS, Geological Sciences, 2011, University of Connecticut

Storrs Lake, a hypersaline lake on the east coast of San Salvador Island, Bahamas, contains well-developed microbial mats, some of which have developed calcified structures called microbialites. Many of these microbialites are laminated, and therefore classified as stromatolites. This study focuses on small stromatolitic knobs located in the southern portion of Storrs lake, which are still actively forming, to gain insights into the early stages of stromatolite formation. These knobs appear to be forming as the result of in situ micritic precipitation mediated by both photosynthetic and heterotrophic microbial metabolisms. By comparing these small stromatolitic knobs to larger stromatolitic heads in deeper portions of the same lake, as well as other modern closed-system and open-marine stromatolites, a mechanism for organomineralization and laminae formation can begin to be determined. The mechanism for in situ precipitation is relatively comparible in each of these systems, though the mechanism of laminae formation varies from microbial to more extrinsic controls. This project can be used to inform future studies of fine-grained stromatolites in the fossil record, providing crucial knowledge about the history of Earth’s carbon cycle. Advisors/Committee Members: Pieter Visscher, Andrew Bush, Christophe Dupraz.

Subjects/Keywords: carbonate; extracellular polymeric substances; hypersaline; microbial mat; microbialite; stromatolite; organomineralization; micrite

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Fowler, A. J. (2011). Stromatolitic Knobs in Storrs Lake, San Salvador, Bahamas: Insights into Organomineralization. (Masters Thesis). University of Connecticut. Retrieved from https://opencommons.uconn.edu/gs_theses/180

Chicago Manual of Style (16th Edition):

Fowler, Alexandre J. “Stromatolitic Knobs in Storrs Lake, San Salvador, Bahamas: Insights into Organomineralization.” 2011. Masters Thesis, University of Connecticut. Accessed July 22, 2019. https://opencommons.uconn.edu/gs_theses/180.

MLA Handbook (7th Edition):

Fowler, Alexandre J. “Stromatolitic Knobs in Storrs Lake, San Salvador, Bahamas: Insights into Organomineralization.” 2011. Web. 22 Jul 2019.

Vancouver:

Fowler AJ. Stromatolitic Knobs in Storrs Lake, San Salvador, Bahamas: Insights into Organomineralization. [Internet] [Masters thesis]. University of Connecticut; 2011. [cited 2019 Jul 22]. Available from: https://opencommons.uconn.edu/gs_theses/180.

Council of Science Editors:

Fowler AJ. Stromatolitic Knobs in Storrs Lake, San Salvador, Bahamas: Insights into Organomineralization. [Masters Thesis]. University of Connecticut; 2011. Available from: https://opencommons.uconn.edu/gs_theses/180


University of South Carolina

2. Bey, Benjamin Senyo. Identification of Quorum Sensing Genes in Hypersaline Microbial Mats.

Degree: PhD, Environmental Health Sciences, 2011, University of South Carolina

Bacteria and other microbes play critical roles in the world by influencing important biochemical processes in the biosphere. However, the bacterial realm remains one of the largest unexplored biological reservoirs on earth. Microbial communities carry out biochemical processes, interactively, by functioning as social units and ultimately define the overall functionality of ecosystems. Bacterial communities in all ecosystems likely utilize signaling pathways to adapt to localized changes in environmental conditions. One such pathway is called quorum sensing (QS), a cell-density dependent phenomenon involving the production, release, and detection of small diffusible signaling molecules referred to as autoinducers. This pathway ultimately coordinates gene expression among the bacterial community leading to synchronized behaviors in a multicellular fashion. Quorum sensing is known to be controlled by synthases of autoinducers and transcriptional regulatory proteins. Among them are LuxI and LuxR homologues; well characterized proteins in several bacterial isolates including Gram-negative and Gram-positive bacteria in laboratory settings under standard conditions. Recent studies have also reported the QS phenomenon in the archaeal domain. Despite the important role quorum sensing plays in community gene regulation, there is little knowledge about its occurrence and relevance in natural ecosystems. This study used functional metagenomic techniques to identify quorum sensing genes in microbial mat communities obtained from Salt Pond on San Salvador Island, The Bahamas. We first extracted high molecular weight metagenomic DNA (> 48 kb) from the microbial mats and used this DNA in the construction of a fosmid-based metagenomic library. Using an approach based on E. coli (JLD271) pEAL01 QS biosensor, we screened 15,000 clones for putative QS activity. Initial screening of the 15, 000 clones showed putative QS activity in 2,975 clones. Following further screening, 302 clones showed consistent putative QS activity. Using 454-sequencing technology, we have sequenced the fosmid inserts of 11 clones, which demonstrated strong biosensor activation. Among a host of hypothetical proteins, we have identified LuxO and LysR; known to be transcriptional regulatory proteins. We also identified genes involved in the synthesis of S-adenosylmethionine (SAM) transferases. S-adenosylmethionine is the precursor for the production of acyl-homoserine lactones (AHL) or autoinducer-2 (AI-2) depending on the biosynthetic pathway. This suggests that the synthesis of QS signaling molecules and the QS phenomenon may be occurring in hypersaline microbial mats. These results also suggest that functional metagenomics can be used to study QS in the natural environment to better understand the role of QS in shaping the structure and functionality of different natural ecosystems. Advisors/Committee Members: R. Sean Norman.

Subjects/Keywords: Medicine and Health Sciences; Public Health; Autoinducer; Biosensor; Hypersaline Microbial Mat; Metagenomics; Qourum Sensing; Transcriptional activator

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Bey, B. S. (2011). Identification of Quorum Sensing Genes in Hypersaline Microbial Mats. (Doctoral Dissertation). University of South Carolina. Retrieved from https://scholarcommons.sc.edu/etd/2652

Chicago Manual of Style (16th Edition):

Bey, Benjamin Senyo. “Identification of Quorum Sensing Genes in Hypersaline Microbial Mats.” 2011. Doctoral Dissertation, University of South Carolina. Accessed July 22, 2019. https://scholarcommons.sc.edu/etd/2652.

MLA Handbook (7th Edition):

Bey, Benjamin Senyo. “Identification of Quorum Sensing Genes in Hypersaline Microbial Mats.” 2011. Web. 22 Jul 2019.

Vancouver:

Bey BS. Identification of Quorum Sensing Genes in Hypersaline Microbial Mats. [Internet] [Doctoral dissertation]. University of South Carolina; 2011. [cited 2019 Jul 22]. Available from: https://scholarcommons.sc.edu/etd/2652.

Council of Science Editors:

Bey BS. Identification of Quorum Sensing Genes in Hypersaline Microbial Mats. [Doctoral Dissertation]. University of South Carolina; 2011. Available from: https://scholarcommons.sc.edu/etd/2652

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