Search

Research has been conducted on the type I and type II methanotrophs, methane-oxidizing bacteria. Results indicate that both types of methanotrophs contain nitrogenase involved in nitrogen fixation and that nitrogenase genes from these methanotrophs may be present in different environments.

Research was conducted to examine novel nitrogen-fixing microbial populations and diverse habitats that can support nitrogen fixation in the open ocean other than those previously reported. Nitrogenase genes were amplified from oligotrophic surface water picoplankton from the tropical Pacific and Atlantic oceans and from the Caribbean and Sargasso seas. Results demonstrate that there are diverse nitrogen-fixing phylotypes in the oceanic environment in the plankton.

The use of immunochemical labelling and electron microscopy helps examine the subcellular distribution of cytochrome oxidase, a respiratory protein in the nonheterocystous marine cyanobacterium Trichodesmium thiebautii. The protein is related to thylakoid and cytoplasmic membranes, and this is indicated by the immunochemical labeling of cytochrome oxidase cells with enhanced nitrogenase levels.

Analysis of the phylogenetic diversity of nitrogenase genes indicate that the genes originate from diverse assemblages and phylogeny as shown by samples collected from nitrogen-poor-, nitrogen-rich hydrothermal vents, and background deep seawater habitats. Data show that nitrogenase genes present in hydrothermal fluids originate from diverse gene assemblages and phylogenetically distinct from deep seawater samples.