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Phospholipids and Glycolipids of the Oral Bacterium Streptococcus mutans UA159

Custer, Jenny Elise
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1307442038

Abstract Details

2011, MS, University of Cincinnati, Arts and Sciences: Biological Sciences.
Streptococcus mutans is a gram-positive oral bacterium that forms biofilms and is the major etiological agent in the formation of dental caries. S. mutans metabolizes sugars and produces lactic acid, which accumulate in the biofilm and lead to a reduction in the environmental pH and demineralization of the tooth enamel. Although previous lipid analyses have been reported for S. mutans strains, in the present study, S. mutans strain UA159 was analyzed since the genome of the strain has been sequenced. Also, the total fatty acid composition of this and other S. mutans strains have been characterized, but there is a lack of information on the fatty acid composition of individual lipid classes and also on the full spectrum of lipids produced by this particular strain. Differences were observed in the lipid composition of organisms at different stages of culture growth. Five lipid classes were detected in log phase cells; however, more than nine lipid components were detected in stationary phase cells. Significant changes in the relative amounts of certain lipid classes present also occurred with the progression from log to stationary phase. The major lipid classes of S. mutans strain UA159 were identified by mass spectrometry (MS) and the definitive structures, including the nature of linkages for the glycosylated lipids were determined by nuclear magnetic resonance (NMR) spectroscopy.. The lipid classes that were identified included glucosyldiacylglycerol (GD), phosphatidylethanolamine (PE), phosphatidylserine (PS), diglucosyldiacylglycerol (DGD), lyso-diglucosylglyceride (lyso-DGG), phosphatidylglycerol (PG), cardiolipin (CL), and glycerophosphoryldiglucosyldiacylglycerol (PG-DGD). Saturated and monounsaturated fatty acids (14:0, 14:1, 16:0, 16:1, 18:0, 18:1, 20:0, 20:1) were identified by gas-liquid chromatography. The major fatty acids were 16:0, 18:1 and 20:1. With increased culture age and cell density there were significant increases in both the relative proportion of unsaturated to saturated fatty acids (&SigmaU/&SigmaS) and in the ratio of short chain (C14 + C16) to long-chain (C18 + C20) fatty acids (&SigmaS/&SigmaL). Analyses of individual lipid classes indicated that changes in the fatty acid composition of the individual lipid classes occurred during culture aging. With the exceptions of PE and PS all other classes detected in both log and stationary phases showed increases in the unsaturation index with increased culture age and an overall increase in chain length. These results indicate that changes seen in the fatty acid profile of the total polar lipid fraction reflects changes in both lipid class composition and changes to the fatty acid profile within individual lipid classes. The results also demonstrate that there is a significant increase in the relative amounts of unsaturated and long chain fatty acids in late stationary phase.
Edna Kaneshiro (Committee Chair)
Katherine Tepperman, PhD (Committee Member)
Eric Villegas, PhD (Committee Member)
112 p.
Biology; Cellular Biology
Streptococcus mutans; fatty acid profile; phospholipids; glycolipids

Recommended Citations

Citations

  • Custer, J. E. (2011). Phospholipids and Glycolipids of the Oral Bacterium Streptococcus mutans UA159 [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1307442038

    APA Style (7th edition)

  • Custer, Jenny. Phospholipids and Glycolipids of the Oral Bacterium Streptococcus mutans UA159. 2011. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1307442038.

    MLA Style (8th edition)

  • Custer, Jenny. "Phospholipids and Glycolipids of the Oral Bacterium Streptococcus mutans UA159." Master's thesis, University of Cincinnati, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1307442038

    Chicago Manual of Style (17th edition)

ucin1307442038
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This open access ETD is published by University of Cincinnati and OhioLINK.