title: Description of 'CandidatusBerkiella aquae' and 'CandidatusBerkiella cookevillensis', two intranuclear bacteria of freshwater amoebae.
abstract: Two novel bacteria of the phylumProteobacteriawere isolated during searches for amoeba-resistant micro-organisms in natural and constructed water systems. Strain HT99 was isolated from amoebae found in the biofilm of an outdoor hot tub in Cookeville, Tennessee, USA, and strain CC99 was isolated from amoebae in the biofilm of a cooling tower in the same city. Both bacteria were Gram-stain-negative cocci to coccobacilli, unculturable on conventional laboratory media, and were found to be intranuclear when maintained inAcanthamoeba polyphaga. The genomes of both isolates were completely sequenced. The genome of CC99 was found to be 3.0 Mbp with a 37.9 mol% DNA G+C content, while the genome of HT99 was 3.6 Mbp with a 39.5 mol% DNA G+C content. The 16S rRNA gene sequences of the two isolates were 94 % similar to each other. Phylogenetic comparisons of the 16S rRNA,mipandrpoBgenes, the DNA G+C content and the fatty acid composition demonstrated that both bacteria are members of the orderLegionellales, and are most closely related toCoxiella burnetii. The phenotypic and genetic evidence supports the proposal of novel taxa to accommodate these strains; however, because strains HT99 and CC99 cannot be cultured outside of the amoeba host, the respective names 'CandidatusBerkiella aquae' and 'CandidatusBerkiella cookevillensis' are proposed.
authors.affiliation: Biology Department, Middle Tennessee State University, Murfreesboro, TN, USA.
authors.forename: Yohannes T
authors.initials: YT
authors.lastname: Mehari
authors.affiliation: Biology Department, Middle Tennessee State University, Murfreesboro, TN, USA.
authors.forename: B
authors.initials: B
authors.lastname: Jason Hayes
authors.affiliation: Center for the Management, Utilization, and Protection of Water Resources, Tennessee Technological University, Cookeville, TN, USA.
authors.forename: Katherine S
authors.initials: KS
authors.lastname: Redding
authors.affiliation: Department of Biology, Tennessee Technological University, Cookeville, TN, USA.
authors.forename: Parvadha V G
authors.initials: PVG
authors.lastname: Mariappan
authors.affiliation: Department of Biology, Tennessee Technological University, Cookeville, TN, USA.
authors.forename: John H
authors.initials: JH
authors.lastname: Gunderson
authors.affiliation: Biology Department, Middle Tennessee State University, Murfreesboro, TN, USA.
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Farone
authors.affiliation: Biology Department, Middle Tennessee State University, Murfreesboro, TN, USA.
authors.forename: Mary B
authors.initials: MB
authors.lastname: Farone