Classical prebiotic chemistry, which has for the last half century explored the reactivity of small organic molecules in glassware environments under the control of chemists, has left unanswered multiple paradoxes with respect to the origins of life. Many of these can be approached, and possibly solved, by placing organic molecular reactivity within the context of the rocks, minerals, hydrosphere, and atmosphere of a prebiotic earth. This new direction in prebiotic chemistry is discussed here, with special emphasis on the role of minerals in constraining the inherent propensity of carbohydrates to devolve to form unproductively complex mixtures of materials. We focus in particular on minerals containing the elements boron and molybdenum, which is produced in discontinuous synthesis model for the emergence of RNA as the first Darwinian molecule. Further, the role of desert environments to manage the “water paradox” is discussed in the context of many classes of processes that have been proposed to deliver RNA under prebiotic conditions. If current models are correct to suggest that early Earth may have been largely flooded at the time when life originated, Then those desert environments may not have been available. However, the inventory of water on Mars has always been less than on Earth and, as Kirschvink has pointed out, intercourse between the two planets was frequent during the time when life is emerging on either planets. This suggests that desert like environments may have been present on early Mars, if they were not present on early Earth.
Assays that target DNA and RNA (xNA) are regarded as the “gold standards” in pathogen detection, surveillance, and diagnostics. However, they are often considered inappropriate for use at points-of-sampling and in low resource environments. This paper discusses innovations created by scientists at the FfAME and Firebird that promise to change this. The first is an artificially expanded genetic information system (AEGIS), a species of DNA having eight nucleotide "letters" added to the four found naturally in DNA. AEGIS nucleobases pair with geometries similar to standard Watson- Crick pairs, but with hydrogen bonding patterns different from (and orthogonal to) patterns that join the A:T and G:C pairs. Thus, AEGIS DNA allows xNA capture and amplification to have very high specificity and very low noise. A second innovation is a self-avoiding molecular recognition system (SAMRS). SAMRS is a species of DNA that behaves the opposite of AEGIS; SAMRS oligonucleotides bind with Watson-Crick complementarity to natural DNA, but not to other SAMRS oligonucleotides. A third innovation is a molecule beacon design that signals the presence of a target xNA even in complex biological mixtures. A fourth innovation is isothermal amplification of xNA targets, without PCR instruments or the skills needed to interpret their output. Here, levels of detection are as few as 30 molecules. Finally, we offer a sample preparation architecture that, as its very first step, sterilizes a sample, rendering it non-hazardous to inexperienced users. It then allows complete xNA capture and CLIA-waivable amplification.
While "life" may universally be a self-sustaining chemical system capable of Darwinian evolution, alien
life may be quite different in its chemistry from the terran life that we know here on Earth. In this case, it
will be difficult to recognize, especially if it has not advanced beyond the single cell life forms that have
dominated much of the terran biosphere. This review summarizes what we might infer from general
physical and chemical law about how such "weird" life might be structured, what solvents other than water
it might inhabit, what genetic molecules it might contain, and what metabolism it might exploit.
The Solar X-ray Imager (SXI) was launched 24 May 2006 on Geostationary Operational Environmental Satellite
(GOES-13). SXI is a grazing incidence X-ray telescope that focuses an image of the Sun onto a CCD detector
through a set of selectable filters. The X-ray image data are transmitted at the rate of at least one image per minute,
which permits the reconstruction of near-real-time solar images in the 6-60Å range (photon energy 2000-200 eV).
Thin film filters consisting of aluminum, titanium, and polyimide are used in the entrance of the telescope to
eliminate visible light. During the first six months of on-orbit operations the amount of stray light transmitted
increased approximately linearly with time, consistent with the formation of small (less than 50 micron) pinholes. A
laboratory investigation was initiated and witness sample filters were subjected to energetic particles simulating the
on-orbit radiation environment and their quality was assessed using visible light-leak testing and scanning electron
microscope imaging. It was concluded that galvanic corrosion of aluminum and titanium initiates pinholes that
subsequently grow in dendritic fashion by spalling off of aluminum to relieve the internal film stress. The test
program also revealed that the geostationary radiation dose level can damage polyimide and lead to filter failure.
Radiation damage may have been responsible in part for the increased light levels observed in the GOES-12 SXI and
with increased exposure a similar observation could manifest on GOES-13 SXI. This paper presents the
methodology and results for the entrance filter test program for the GOES SXI telescopes and presents recommended
improvements for future instruments.
We have designed, synthesized, and investigated a novel molecular beacon (MB) using locked nucleic acid (LNA) bases for intracellular mRNA monitoring. This new LNA-MB has several useful properties including: very high melting temperature; excellent affinity for complementary sequences; superior single base mismatch discrimination capability; stablity against nuclease digestion; and not binding with single-stranded DNA binding proteins. All of these properties are highly advantageous for a molecular tool for various intracellular studies of biochemical, biological and medical significance.
Conference Committee Involvement (4)
Instruments, Methods, and Missions for Astrobiology XVII
9 August 2015 | San Diego, California, United States
Instruments, Methods, and Missions for Astrobiology XVI
27 August 2013 | San Diego, California, United States
Instruments, Methods, and Missions for Astrobiology XIV
23 August 2011 | San Diego, California, United States
Instruments, Methods, and Missions for Astrobiology XIII
3 August 2010 | San Diego, California, United States