Did Bacterial Enzymes Cap the Oxygen in Early Earth’s Atmosphere?

Energetic oxygen in the upper atmosphere and the laboratory.

Studies on Bacterial Enzymes

The meningococcus cell contains a peptonase enzyme which hydrolyzes the peptides and similar constituents of commercial "peptone." The activity of this enzyme is independent of the presence of the formed bacterial cell. The peptonase enzyme is more resistant to heat and to oxidation than is the maltase enzyme of the same bacteria.

Bacterial enzymes Hyaluronidase

Bacterial enzyme ‘Hyaluronidase’ is a complex polysaccharide degrading enzyme that cleaves â-GlcNAc-(14) glycosidic linkage of Hyaluronate (HA) by â-elimination process. It is synthesized by a spectrum of grampositive bacteria which serve as potential contributors to a multitude of infectious diseases in human beings. Especially, group A streptococcus bacteria (GAS) have evolved several orders...

Did earthquakes keep the early crust habitable?

The shallow habitable region of cratonal crust deforms with a strain rate on the order of approximately 10(19) s(1). This is rapid enough that small seismic events are expected on one-kilometer spatial scales and one-million-year timescales. Rock faulting has the potential to release batches of biological substrate, such as dissolved H(2), permitting transient blooms. In addition, the steady-st...

Oxygen isotopic composition of carbon dioxide in the middle atmosphere.

The isotopic composition of long-lived trace molecules provides a window into atmospheric transport and chemistry. Carbon dioxide is a particularly powerful tracer, because its abundance remains >100 parts per million by volume (ppmv) in the mesosphere. Here, we successfully reproduce the isotopic composition of CO(2) in the middle atmosphere, which has not been previously reported. The mass-in...