Development of life detection technologies based on bacterial endospore photochemistry and amino acid chirality: From medical sterilization, biodefens

Development of life detection technologies based on bacterial endospore photochemistry and amino acid chirality: From medical sterilization, biodefense to astrobiology

Abstract:

This seminar outlines novel technological development for the detection of extant and extinct life and based on bacterial endospore photochemistry and amino acid chirality. Valuable information on the advancement of medical sterilization, biodefense and astrobiology can also be gleaned from this endeavor.

Bacterial endospores are dormant and resistant structures formed primarily from Bacillus and Clostridium genera. Dipicolinic acid (DPA) is a major constituent and unique chemical marker of endospores. When released via germination or physical rupture, DPA can bind to terbium ions (Tb3+) to form highly-luminescent terbium dipicolinate [Tb(DPA)]+. They can be used to assure the sterility level in medical and spacecraft assembly facilities. The patented Anthrax Smoke Detector thus developed has been sold as a front-end monitor for anthrax attack surveillance. Trace amount of endospores have also been detected and isolated from Arctic ice cores, Atacama Desert soils and other places to understand the longevity and survival strategies of these extremophiles.

Another life detection technology is the Urey organic and oxidant detector, which has been selected for the European Space Agency's upcoming 2013 ExoMars rover mission. It performs a complete inventory of chemical markers in the Martian regolith and determines whether the origins of these compounds were from biotic or abiotic processes using chirality measurements. It consists of three steps: 1) subcritical water extraction of biomarkers from regolith samples, 2) liquid chromatographic separation of extracted biomarkers, and 3) their subsequent detection and analysis. This seminar highlights the microcapillary electrochromatography (μCEC) in a lab-on-a-chip format that enables separation of a mixture of neutral organic molecules.