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Nitrosopumilus maritimus

Genome and Cell Division
Ammonia-oxidizing bacteria (AOB) are known to have a chemolitoautotrophycal growth by using inorganic carbon, N. Maritimus, an Ammonia-oxidizing archaea (AOA) use a similar process of growth. While AOB uses Calvin–Bassham–Benson cycle with the CO2-fixing enzyme ribulose bisphosphate carboxylase/oxygenase (RubisCO) as the key enzyme; N. Maritimus seems to grow and use an alternative pathway due to the lack of genes and enzymes. Therefore, a variant of the 3-hydroxypropionate/4-hydroxybutyrate is used by N. Maritimus to develop autotrophically, which allows its capacity to assimilate organic carbon. Using the 3-hydroxypropionate/4-hydroxybutyrate pathway method instead of the Calvin–Bassham–Benson cycle, N. Maritimus could provide a growth advantage as the process is more energy-efficient. Due to its originality, N. Maritimus plays an essential role in the carbon and nitrogen cycle

Euryarchaeota, Crenarchaeota, and Thaumarchaeota are the three major Phylum of Archaea which use cell division to duplicate. Euryarchaeota and Bacteria use the FtsZ mechanism in cell division, while Crenarchaeota divide using the Cvd machinery. However, Thaumarchaeota such as N. Maritimus adopts both mechanisms, FtsZ and Cdv. Nevertheless, after further researches, N. Maritimus was found to use mainly Cvd proteins rather than FtsZ during cell division. In this case, Cvd is the primary system in cell division for N. Maritimus. Therefore, to replicate a genome of 1.645Mb, N. Maritimus spends 15 to 18 hours.