Nanostructured manganese oxides as highly active catalysts for enhanced hydrolysis of bis(4-nitrophenyl)phosphate and catalytic decomposition of methanol

The nanostructured manganese oxides (MnOx) exhibited high catalytic activities for hydrolysis of phosphate diester-based substrate bis(4-nitrophenyl)phosphate and decomposition of methanol to carbon monoxide and hydrogen as a potential alternative fuel.

Phosphate diester utilization by marine diazotrophs Trichodesmium erythraeum and Crocosphaera watsonii

In the phosphate-depleted oligotrophic ocean, microbes utilize various dissolved organic phosphorus (P) compounds as alternative P sources, using enzymes such as alkaline phosphatases. However, knowledge of such P acquisition mechanisms is limited, especially in association with the physiology of nitrogen-fixing organisms, which play a substantial role in marine biogeochemical cycling. We show that nonaxenic clonal cultures of 2 oceanic diazotrophs, Trichodesmium erythraeum and Crocosphaera watsonii, have the ability to utilize phosphate diester as their sole P source, using a model artificial compound—bis-p-nitrophenyl phosphate (bisNPP). Although both diazotroph cultures likely preferred phosphate monoester to diester, the expressed diesterase activity was theoretically sufficient to fulfill their P demands, and they showed significant growth in bisNPP-added media. Interestingly, a distinct difference in their growth trends was observed, with faster onset of growth by C. watsonii and delayed onset of growth by T. erythraeum. This indicates that the C. watsonii consortium can effectively and rapidly assimilate in situ diesters as alternative P sources in the field. Nonetheless, when considering the poor bisNPP utilization reported from other marine phytoplankton taxa, our results indicate that the utilization of particular diester compounds is a notable and advantageous strategy for both diazotroph consortia to alleviate P limitation in the oligotrophic ocean.

Solvation and Stabilization of Single Strand RNA at the Air/ice Interface Support a Primordial RNA World on Ice

<div>Outstanding questions about the RNA world hypothesis for the emergence of life</div><div>on Earth concern the stability and self-replication of prebiotic aqueous RNA.</div><div>Recent experimental work has suggested that solid substrates and low</div><div>temperatures could help resolve these issues. Here, we use classical molecular</div><div>dynamics simulations to explore the possibility that the substrate is ice itself. We</div><div>find that at -20 C, a quasi-liquid layer at the air/ice interface solvates a short (8-</div><div>nucleotide) RNA strand such that phosphate groups tend to anchor to specific</div><div>points of the underlying crystal lattice, lengthening the strand. Hydrophobic bases,</div><div>meanwhile, tend to migrate to the air/ice interface. Further, contacts between</div><div>solvent water and ribose 2-OH’ groups are found to occur less frequently for RNA</div><div>on ice than for aqueous RNA at the same temperature; this reduces the likelihood</div><div>of deprotonation of the 2-OH’ and its subsequent nucleophilic attack on the</div><div>phosphate diester. The implied enhanced resistance to hydrolysis, in turn, could</div><div>increase opportunities for polymerization and self-copying. These findings thus</div><div>offer the possibility of a role for an ancient RNA world on ice distinct from that</div><div>considered in extant elaborations of the RNA world hypothesis. This work is, to the</div><div>best of our knowledge, the first molecular dynamics study of RNA on ice</div>

Solvation and Stabilization of Single Strand RNA at the Air/ice Interface Support a Primordial RNA World on Ice

<div>Outstanding questions about the RNA world hypothesis for the emergence of life</div><div>on Earth concern the stability and self-replication of prebiotic aqueous RNA.</div><div>Recent experimental work has suggested that solid substrates and low</div><div>temperatures could help resolve these issues. Here, we use classical molecular</div><div>dynamics simulations to explore the possibility that the substrate is ice itself. We</div><div>find that at -20 C, a quasi-liquid layer at the air/ice interface solvates a short (8-</div><div>nucleotide) RNA strand such that phosphate groups tend to anchor to specific</div><div>points of the underlying crystal lattice, lengthening the strand. Hydrophobic bases,</div><div>meanwhile, tend to migrate to the air/ice interface. Further, contacts between</div><div>solvent water and ribose 2-OH’ groups are found to occur less frequently for RNA</div><div>on ice than for aqueous RNA at the same temperature; this reduces the likelihood</div><div>of deprotonation of the 2-OH’ and its subsequent nucleophilic attack on the</div><div>phosphate diester. The implied enhanced resistance to hydrolysis, in turn, could</div><div>increase opportunities for polymerization and self-copying. These findings thus</div><div>offer the possibility of a role for an ancient RNA world on ice distinct from that</div><div>considered in extant elaborations of the RNA world hypothesis. This work is, to the</div><div>best of our knowledge, the first molecular dynamics study of RNA on ice</div>

Molecular Dynamics simulations indicate solvation and stability of single-strand RNA at the air/ice interface, supporting a primordial RNA world on Ice

&lt;p&gt;Outstanding questions about the RNA world hypothesis for the emergence of life on Earth concern the stability and self-replication of prebiotic aqueous RNA. Recent experimental work has suggested that solid substrates and low temperatures could help resolve these issues. Here, we use classical molecular dynamics simulations to explore the possibility that the substrate is ice itself. We find that at -20 C, a quasi-liquid layer at the air/ice interface partially solvates a short (8-nucleotide) RNA strand such that the phosphate backbone anchors to the underlying crystalline ice structure though long-lived hydrogen bonds. The hydrophobic bases, meanwhile, are seen to migrate toward the outermost layer, exposed to air. Our simulations also reveal two key kinetic differences with respect to aqueous RNA. First, hydrogen bonds between solvent water molecules and phosphate diester moieties, believed to shield the RNA from hydrolysis, are much longer-lived for RNA on ice, compared to aqueous RNA at the same temperature. Second, contact between solvent water and ribose 2-OH&amp;#8217; groups, considered a precursor to nucleophilic attack by deprotonated 2-OH&amp;#8217; on the phosphate diester, is significantly less frequent for RNA on ice. Both differences point to lower susceptibility to hydrolysis of RNA on ice, and therefore increased opportunities for polymerization and self-copying compared to aqueous RNA. Moreover, exposure of hydrophobic bases at the air/ice interface offers opportunities for reaction that are not readily available to aqueous RNA (e.g., base-pairing reaction with free nucleotides diffusing across the air/ice interface). These findings thus offer the possibility of a role for an ancient RNA world on ice distinct from that considered in extant elaborations of the RNA world hypothesis. This work is, to the best of our knowledge, the first molecular dynamics study of RNA on ice.&lt;/p&gt;