Abstract
Aquisphaera (A.qui.sphae'ra. L. fem. n. aqua water; L. fem. n. sphaera a ball, globe, sphere; N.L. fem. n. Aquisphaera a spherical bacterium living in freshwater).
Planctomycetes / Planctomycetia / Isosphaerales / Isosphaeraceae / Aquisphaera
The genus Aquisphaera accommodates Gram-negative, spherical, and nonmotile bacteria that form small, translucent, smooth, and light pink-pigmented colonies. Crater-like structures are distributed around the cell surface. Depending on the medium composition, cells can form large glycocalyces. Extremely large aggregates can be formed in liquid medium. Thin cell sections reveal extensive invaginations of the cytoplasmic membrane. Reproduction occurs by budding resembling budding fission. Chemoheterotrophic, strictly aerobic, catalase- and cytochrome oxidase-positive. Vitamin B12 required for growth. Mesophilic (30–35°C), slightly alkaliphilic, and sensitive to NaCl. The major fatty acids are C18:1 ω9c and C16:0. The predominant phospholipids are phosphatidylcholine and phosphatidylglycerol. MK-6 is the major menaquinone oxidized. Members of the class Planctomycetia, order Isosphaerales, family Isosphaeraceae. Known habitats are freshwater sediments.
DNA G + C content (mol%): 70.8 (genome sequence).
Type species: Aquisphaera giovannonii Bondoso et al. 2011VP.
