title: Comparative genomic evidence for a close relationship between the dimorphic prosthecate bacteria Hyphomonas neptunium and Caulobacter crescentus.
abstract: The dimorphic prosthecate bacteria (DPB) are alpha-proteobacteria that reproduce in an asymmetric manner rather than by binary fission and are of interest as simple models of development. Prior to this work, the only member of this group for which genome sequence was available was the model freshwater organism Caulobacter crescentus. Here we describe the genome sequence of Hyphomonas neptunium, a marine member of the DPB that differs from C. crescentus in that H. neptunium uses its stalk as a reproductive structure. Genome analysis indicates that this organism shares more genes with C. crescentus than it does with Silicibacter pomeroyi (a closer relative according to 16S rRNA phylogeny), that it relies upon a heterotrophic strategy utilizing a wide range of substrates, that its cell cycle is likely to be regulated in a similar manner to that of C. crescentus, and that the outer membrane complements of H. neptunium and C. crescentus are remarkably similar. H. neptunium swarmer cells are highly motile via a single polar flagellum. With the exception of cheY and cheR, genes required for chemotaxis were absent in the H. neptunium genome. Consistent with this observation, H. neptunium swarmer cells did not respond to any chemotactic stimuli that were tested, which suggests that H. neptunium motility is a random dispersal mechanism for swarmer cells rather than a stimulus-controlled navigation system for locating specific environments. In addition to providing insights into bacterial development, the H. neptunium genome will provide an important resource for the study of other interesting biological processes including chromosome segregation, polar growth, and cell aging.
authors.affiliation: The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA. jbadger@tigr.org
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Badger
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Hoover
authors.forename: Yves V
authors.initials: YV
authors.lastname: Brun
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Weiner
authors.forename: Michael T
authors.initials: MT
authors.lastname: Laub
authors.forename: Gladys
authors.initials: G
authors.lastname: Alexandre
authors.forename: Jan
authors.initials: J
authors.lastname: Mrázek
authors.forename: Qinghu
authors.initials: Q
authors.lastname: Ren
authors.forename: Ian T
authors.initials: IT
authors.lastname: Paulsen
authors.forename: Karen E
authors.initials: KE
authors.lastname: Nelson
authors.forename: Hoda M
authors.initials: HM
authors.lastname: Khouri
authors.forename: Diana
authors.initials: D
authors.lastname: Radune
authors.forename: Julia
authors.initials: J
authors.lastname: Sosa
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Dodson
authors.forename: Steven A
authors.initials: SA
authors.lastname: Sullivan
authors.forename: M J
authors.initials: MJ
authors.lastname: Rosovitz
authors.forename: Ramana
authors.initials: R
authors.lastname: Madupu
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Brinkac
authors.forename: A Scott
authors.initials: AS
authors.lastname: Durkin
authors.forename: Sean C
authors.initials: SC
authors.lastname: Daugherty
authors.forename: Sagar P
authors.initials: SP
authors.lastname: Kothari
authors.forename: Michelle Gwinn
authors.initials: MG
authors.lastname: Giglio
authors.forename: Liwei
authors.initials: L
authors.lastname: Zhou
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Haft
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Selengut
authors.forename: Tanja M
authors.initials: TM
authors.lastname: Davidsen
authors.forename: Qi
authors.initials: Q
authors.lastname: Yang
authors.forename: Nikhat
authors.initials: N
authors.lastname: Zafar
authors.forename: Naomi L
authors.initials: NL
authors.lastname: Ward
mesh_terms: D020561:Alphaproteobacteria / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D016935:Caulobacter crescentus / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D002453:Cell Cycle / Q000235:genetics; D002633:Chemotaxis / Q000235:genetics / Q000502:physiology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005407:Flagella / Q000502:physiology; D016680:Genome, Bacterial; D050296:Microbial Viability; D008969:Molecular Sequence Data; D009068:Movement; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D015398:Signal Transduction
chemical_list: D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial