Clair E. Folsome

Mutagenesis of Anacystis nidulans by N-methyl-N′-nitro-N-nitrosoguanidine and UV irradiation

Abstract Inactivation of the blue-green alga, Anacystis nidulans , with nitrosoguanidine was concentration-dependent. Nitrosoguanidine-induced mutation frequencies were: 1.8 · 10 −3 , 2.98 · 10[su−3], 3.7 · 10 −3 , 1.0 · 10 −3 and 4.8 · 10 −4 for yellow and blue, minute-colony-forming, filamentous or snake, and polymixin-B-resistant mutants, respectively. UV-irradiated damage within the experimental conditions utilized was completely photoreactivity by visible light. When a UV-irradiated culture was incubated in the dark for 9 h, a survival curve with slope k = −0.066 ( where k = ln S S 0 · t −1 ) was observed. A small shoulder was evident, and the extrapolation of the asymptote of the curve to the ordinate showed an inactivation number of 2. Minute-colony-forming and snake mutants were also induced by UV irradiation if photoreactivation was prevented. The inability to isolate auxotrophic mutants of Anacystis nidulans was considered to be due to intrinsic properties and therefore presents a major problem in blue-green algal genetics.

Synthetic organic microstructures and the origins of cellular life

Synthetic organic microstructures are produced in high yield in quenched spark-discharge reactions upon CO, CH4 and N2 gases over a water surface. The properties of these structures are reviewed and compared to coacervates, proteinoid microspheres, and Archean microfossils. The findings suggest that microstructures appear to be abiological organic particles which are precursors to the first living cell.

Prebiological membranes: Synthesis and properties

Ultraviolet irradiation of alkanes on aqueous solutions of phosphate and magnesium yields complex structured products which bear many properties similar to simple membranes. The relevance of this product to prebiologic evolution is discussed from the point of view of phase spparation.

Photochemical synthesis of biomolecules under anoxic conditions

We report the long-wavelength UV anoxic photosynthesis of uracil, various sugars (including deoxyribose and glycoaldehyde), amino acids, and other organic photoproducts. These reactions occur in mixtures of water, calcium carbonate, formaldehyde and hydrazine. Our data demonstrate that under several sets of conditions biomolecules can be formed in variety and abundance from reduced compounds (formaldehyde and hydrazine) derived from anoxic dinitrogen/carbon dioxide environments. The formaldehyde concentrations were varied from 10 mM to 0.005 mM, and the hydrazine concentrations were varied from 1 mM to 0.01 mM. The highest of these reactant concentrations were 500 and 6 times greater than those reported for earlier experiments upon the synthesis of these precursors from CO2 or N2, while the lowest of reactant concentrations employed here were 0.5 (formaldehyde) and 0.006 (hydrazine). Product yields were greatest when the hydrazine/formaldehyde ratio was 1, and when the reactant concentrations were low. These data suggest that organic products can be formed in variety from those amounts of formaldehyde and hydrazine precursors which are themselves formed under anoxic UV photochemical conditions. Hence these various reactions would seem to have prebiotic relevance. The UV 254 nm photon flux employed was 100 times higher than unattenuated solar flux. Durations of UV exposure were 24 hrs and 72 hrs. No experiments have been addressed to the possibility of UV flux dependency.

Exponential kinetics of formation of organic microstructures

Organic microstructure production in Miller-Urey spark discharge flasks is an energydependent, autocatalytic process which follows first order kinetics similar to microbial growth curves. These relationships hold for all three major morphological types of microstructures observed. The three types are assembled from smaller precursor subunits which associated according to a binomial distribution. These structures could have formed bounded systems in which pre-biological processes might have occurred.

Lack of bacterial survival under Cytherean-oriented conditions

Representatives of 3 genera of bacteria when subjected to high temperatures and high pressures of CO2 simultaneously while in liquid culture do not survive.

Venus: Where has all the water gone?

Conditions on the surface of venus are reviewed and evidence for the existence of a hydrosphere assessed. Escape mechanisms are examined and found to be insufficient to explain the presumed absence of liquid water on venus. The consequences of a hot, acidic hydrosphere are explored as is marginal evidence for biological activity.