Levels of Ca2+-Dipicolinic Acid in Individual Bacillus Spores Determined Using Microfluidic Raman Tweezers

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

De Chen (Creator)

Shu-shi Huang (Creator)

Yong-qing Li (Creator)

Patricia L. Pelczar (Creator)

Peter Setlow (Creator)

Venkata Ramana Vepachedu (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Pyridine-2 6-dicarboxylic acid (dipicolinic acid [DPA]) in a 1:1 chelate with calcium ion (Ca-DPA) comprises 5 to 15% of the dry weight of spores of Bacillus species. Ca-DPA is important in spore resistance to many environmental stresses and in spore stability and Ca-DPA levels in spore populations can vary with spore species/strains as well as with sporulation conditions. We have measured levels of Ca-DPA in large numbers of individual spores in populations of a variety of Bacillus species and strains by using microfluidic Raman tweezers in which a single spore is trapped in a focused laser beam and its Ca-DPA is quantitated from the intensity of the Ca-DPA-specific band at 1 017 cm!1 in Raman spectroscopy. Conclusions from these measurements include the following: (i) Ca-DPA concentrations in the spore core are >800 mM well above Ca-DPA solubility; (ii) SpoVA proteins may be involved in Ca-DPA uptake in sporulation; and (iii) Ca-DPA levels differ significantly among individual spores in a population but much of this variation could be due to variations in the sizes of individual spores. Originally published Journal of Bacteriology Vol. 189 No. 13 July 2007

Additional Information

Publication

Other

Journal of Bacteriology. 189:13(July 2007) p. 4681-4687.

Language: English

Date: 2011

Keywords

Bacillus spores, Ca-DPA, Raman spectroscopy

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