Deamer, David

Wenonah Vercoutere, Stephen Winters-Hilt, Hugh Olsen, David Deamer, David Haussler, Mark Akeson, Rapid discrimination among individual DNA haiipin molecules at single-nucleotide resolution using an ion channel. Nature Biotechnology, 19 (2001), 248-252. 

Thus, the question is whether such classes of molecules were present on the young Earth. The only witnesses capable of giving an answer to this question are meteorites (Deamer, 1988). The group of David Deamer studied Murchison material after extraction and hydropyrolysis (at 370-570 K, with reaction times of several hours or days). GC and MS analyses showed the presence of a series of organic compounds, including significant amounts of amphiphilic molecules such as octanoic (C ) and nonanoic acids (C9) as well as polar aromatic hydrocarbons. 

Figure 9.29 Membrane formation by meteoritic amphiphilic compounds (courtesy of David Deamer). A sample of the Murchison meteorite was extracted with the chloroform-methanol-water solvent described by Deamer and Pashley, 1989. Amphiphilic compounds were isolated chromatographically on thin-layer chromatography plates (fraction 1), and a small aliquot ( 1 p,g) was dried on a glass microscope slide. Alkaline carbonate buffer (15 p,l, 10 mM, pH 9.0) was added to the dried sample, followed by a cover slip, and the interaction of the aqueous phase with the sample was followed by phase-contrast and fluorescence microscopy, (a) The sample-buffer interface was 1 min. The aqueous phase penetrated the viscous sample, causing spherical structures to appear at the interface and fall away into the medium, (b) After 30 min, large numbers of vesicular structures are produced as the buffer further penetrates the sample, (c) The vesicular nature of the structures in (b) is clearly demonstrated by fluorescence microscopy. Original magnification in (a) is x 160 in (b) and (c) x 400.

A number of colleagues were very kind and helpful with their advice. I would like to thank Antonio Lazcano, and Albert Eschenmoser, who in different ways helped me with their frank comments and Meir Lahav, Joseph Ribo, Jeffrey Bada, and David Deamer. Particular thanks are due to Dr. Pasquale Stano, whose help has been essenhal, particularly, but not only, with the bibliography also Rachel Fajella helped with the editing of some parts of the manuscript. I am also particularly indebted to Angelo Merante for the illustrahons and the formatting of the manuscript without him, the manuscript would shll be in my drawers. Last, but not least, I want to thank my students of the University of Rome 3, their positive feedback at the very early stages of the manuscript was very important. 

There are several possibilities. As found by the American investigator David Deamer (1998), small amounts of molecules capable of assembling into bilayers, probably medium-length fatty acids, can be extracted from meteorites, suggesting a possible cosmic origin of the first amphiphilic molecules. 

Crystal Structure of [Bis(L-Alaninato)Diaqua]Nickel(II) Dihydrate 263 AwniKhatib, FathiAqra, David Deamer and Allen Oliver... 

Awni Khatib, Fathi Aqra, David Deamer and Allen Oliver... 

Edited by David W. Deamer, Arnost Kleinzeller, and Douglas M. Fambrough... 

Some meteorites do something amazing—they blow bubbles as they dissolve. David Deamer and Louis Allamandola led a team of researchers who observed this. When they mixed an extract from the meteorite in water, all sorts of carbon-rich oily molecules grouped together, like oil tends to do. These were special, hollow drops called vesicles, like bubbles blown in water with water in the middle. 

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