Abstract
He.pat.in'co.la. Gr. neut. n.
hêpar (gen. hêpatos)
, liver; L. masc./fem. n.
incola
, inhabitant, dweller; N.L. masc. n.
Hepatincola
, a dweller of the liver.
Pseudomonadota / Alphaproteobacteria / Rhodospirilalles / Candidatus Hepatincolaceae /
Candidatus
Hepatincola
Candidatus
Hepatincola is a genus of uncultured, obligately host‐associated bacteria originally discovered in the lumen of the midgut glands (hepatopancreas) of terrestrial isopods. In this niche, the bacteria exhibit a characteristic morphology: elongated rods with a stalk‐like appendage at one pole, which can be inserted between the microvilli of the midgut epithelium. All known members of the genus belong to two species (
Ca
. Hepatincola porcellionum and a yet to be named
Ca
. Hepatincola sp.) associated with terrestrial isopods. However, closely related genera from the same family have been observed in numerous aquatic and terrestrial members of the Ecdysozoa (molting invertebrates).
Ca
. Hepatincola and closely related genera all have reduced genomes of about 1.3 Mb with low DNA G + C content (
c
. 30%) and extremely limited biosynthetic capacities but rich in transporters to import essential nutrients and precursors from the environment. In line with its ecological niche (the host gut lumen, a nutrient‐rich environment) and genomic characteristics,
Ca
. Hepatincola is rather a nutrient scavenger than a nutrient provider for the host.
Ca
. Hepatincola was initially classified within the order
Rickettsiales
and later within the
Holosporales
, but recent phylogenomic analyses support its phylogenetic placement within the order
Rhodospirillales
.
DNA G
+
C content (mol
%
)
: 30.
Type species
:
Candidatus
Hepatincola porcellionum
Wang et al. (2004), CL1.