Pontibacter diazotrophicus sp. nov., a Novel Nitrogen-Fixing Bacterium of the Family Cytophagaceae

Abstract

Few diazotrophs have been found to belong to the family Cytophagaceae so far. In the present study, a Gram-negative, rod-shaped bacterium that forms red colonies, was isolated from sands of the Takalamakan desert. It was designated H4XT. Phylogenetic and biochemical analysis indicated that the isolate is a new species of the genus Pontibacter. The 16S rRNA gene of H4XT displays 94.2–96.8% sequence similarities to those of other strains in Pontibacter. The major respiratory quinone is menaquinone-7 (MK-7). The DNA G+C content is 46.6 mol%. The major cellular fatty acids are iso-C15∶0, C16∶1ω5c, summed feature 3 (containing C16∶1ω6c and/or C16∶1ω7c) and summed feature 4 (comprising anteiso-C17∶1B and/or iso-C17∶1I). The major polar lipids are phosphatidylethanolamine (PE), one aminophospholipid (APL) and some unknown phospholipids (PLs). It is interesting to see that this bacterium can grow very well in a nitrogen-free medium. PCR amplification suggested that the bacterium possesses at least one type of nitrogenase gene. Acetylene reduction assay showed that H4XT actually possesses nitrogen-fixing activity. Therefore, it can be concluded that H4XT is a new diazotroph. We thus referred it to as Pontibacter diazotrophicus sp. nov. The type strain is H4XT ( = CCTCC AB 2013049T = NRRL B-59974T).

Microbially Mediated Methylation of Arsenic in the Arsenic-Rich Soils and Sediments of Jianghan Plain

“…Multiple sequence alignments were conducted using the ClustalW2 software as described elsewhere ( Zhang et al, 2015 ; Mu et al, 2016a ). A phylogenetic tree of the obtained ArsMs and their closely related homologues was constructed using the maximum likelihood method implemented in MEGA 6.0 as described previously ( Xu et al, 2014 ; Mu et al, 2016b ).…”

Pontibacter ummariensis sp. nov., isolated from a hexachlorocyclohexane-contaminated soil

“…Type strains of this genus are widely distributed and have been isolated mainly from soil samples, collected from deserts (Zhou et al, 2007;Cao et al, 2014;Subhash et al, 2014), pond sediment (Singh et al, 2013, solar salterns (Joung et al, 2011Subhash et al, 2013), forests (Dastager et al, 2010;Xu et al, 2012), mountains (Srinivasan et al, 2014), the plant rhizosphere (Raichand et al, 2011;Dai et al, 2014) and hexachlorocyclohexane (HCH) dumpsites (Dwivedi et al, 2013;Singh et al, 2014). Apart from soil samples, strains have also been isolated from a marine coelenterate (Nedashkovskaya et al, 2005), desert sand (Zhang et al, 2008;Xu et al, 2014), sea water and muddy water (Suresh et al, 2006;Wang et al, 2010). The present study was designed to characterize taxonomically a novel bacterial strain, NKM1…”

Pontibacter amylolyticus sp. nov., isolated from a deep-sea sediment hydrothermal vent field

“…At the time of writing, the genus Pontibacter comprised 20 species with validly published names. Members of the genus Pontibacter have been isolated from an actinian (Nedashkovskaya et al, 2005), seawater (Kang et al, 2013), a solar saltern (Subhash et al, 2013), a drainage system (Suresh et al, 2006), soils (Dastager et al, 2010;Wang et al, 2010;Xu et al, 2012;Cao et al, 2014;Dai et al, 2014;Srinivasan et al, 2014), hexachlorocyclohexanecontaminated soils (Dwivedi et al, 2013;Singh et al, 2013Singh et al, , 2014Singh et al, , 2015, and desert soils or sands Zhang et al, 2008Zhang et al, , 2013Subhash et al, 2014;Xu et al, 2014). Three additional species, 'Pontibacter salisaro' (Joung et al, 2011), 'Pontibacter rhizosphera' (Raichand et al, 2011) and 'Pontibacter jeungdoensis' (Joung et al, 2013) have been described; however, the names had not validly published as of September 2015.…”