Abstract
Ni.tro.so.cal'dus. N.L. adj.
nitrosus
nitrous; L. masc. adj.
caldus
hot; N.L. masc. n.
Nitrosocaldus
a nitrite producer at thermophilic growth temperatures.
Thermophilic, neutrophilic, autotrophic, and aerobic ammonia‐oxidizing archaea. Urea can be used as a source of energy for growth. Cells fix CO
2
via a modified 3‐hydroxypropionate/4‐hydroxybutyrate carbon fixation pathway. Cells are irregular cocci between 0.65 and 0.75 microns in diameter. Cells reproduce by binary fission. Cell membrane lipids consist mainly of acyclic and cyclized glycerol trialkyl glycerol tetraethers (GTGTs) and glycerol dibiphytanyl glycerol tetraethers (GDGTs), with acyclic GTGT and crenarchaeol as the dominant components. Quinone systems include menaquinones with fully saturated and monounsaturated side chains that comprised six isoprenoid units. The members of the genus
Ca
. Nitrosocaldus can be found in neutral or slightly alkaline terrestrial geothermal environments at temperatures ranging from 65 to 85°C. Phylogenetic analysis on the basis of both 16S rRNA and
amoA
genes supports the monophyletic genus
Ca
. Nitrosocaldus within the family
Ca
. Nitrosocaldaceae.
DNA G + C content (mol%)
: 37.1.
Type species
:
Ca
.
Nitrosocaldus yellowstonensis
(Nitrosocaldus yellowstonii) de la Torre, Walker, Ingalls, Könneke and Stahl 2008, 815.
Taxonomic and Nomenclature Notes
According to the List of Prokaryotic names with Standing in Nomenclature (LPSN), the taxonomic status of the genus
Candidatus Nitrosocaldus
is: preferred name (not correct name) (last update, February 2025)
*
.
LPSN classification:
Archaea
/
Thermoproteati
/
Thermoproteota
/
incertae sedis
/
Candidatus Nitrosocaldales
/
Candidatus Nitrosocaldaceae
/
Candidatus Nitrosocaldus
The genus
Candidatus Nitrosocaldus
can also be recovered in the Genome Taxonomy Database (GTDB) as
g__Nitrosocaldus
(version v220)
**
.
GTDB classification:
d__Archaea
/
p__Thermoproteota
/
c__Nitrososphaeria
/
o__Nitrososphaerales
/
f__Nitrosocaldaceae
/
g__Nitrosocaldus
*
Meier‐Kolthoff
et al. (
2022
).
Nucleic Acids Res
,
50
,
D801
–
D807
; DOI:
10.1093/nar/gkab902
**
Parks
et al. (
2022
).
Nucleic Acids Res
,
50
,
D785
–
D794
; DOI:
10.1093/nar/gkab776