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).

A novel arsenic-resistant bacterium, designated 42-50T, was isolated from the high-arsenic sediment of Jianghan Plain, Hubei Province, China. Phylogenetic and biochemical analysis indicated that this bacterium represents the first species of a novel genus belonging to the family Hyphomicrobiaceae. The 16S rRNA gene of strain 42-50T shares 96.3-94.2, 96.3, 96.2 and 94.9-93.8 % sequence identities to those of species from the genera Devosia, Youhaiella, Paradevosia and Pelagibacterium, respectively. The major cellular fatty acids are C16 : 0, C18 : 0, C18 : 1ω7c 11-methyl and summed feature 8 (comprising C18 : 1ω7c and C18 : 1ω6c). The predominant polar lipids are diphosphatidylglycerol, phosphatidylglycerol and two unidentified glycolipids. The predominant respiratory quinone is ubiquinone-10 (Q-10). The DNA G+C content of strain 42-50T is 73.7 mol%. The distinct phylogenetic lineage and unique cellular fatty acids suggest that strain 42-50T represents a novel species of a new genus affiliated with the family Hyphomicrobiaceae, for which the name Arsenicitalea aurantiaca gen. nov., sp. nov. is proposed. The type strain is 42-50T (=CCTCC AB 2014325T=KCTC 42825T).

A Gram-stain-negative, rod-shaped bacterium that formed yellow and viscous colonies was isolated from arsenic-contaminated soil of the Jianghan plain, Hubei Province, China, and it was designated 26-35 T . This strain was capable of resisting arsenate and arsenite with MICs of 40 and 20 mM, respectively. The 16S rRNA gene of the novel isolate displayed 96.7-94.2 % sequence similarities to those of other known species of the genus Luteimonas. The respiratory quinone was ubiquinone-8 (Q-8). The DNA G+C content was 71.4 mol%. The predominant cellular fatty acids were iso-C 15 : 0 , iso-C 16 : 0 , iso-C 17 : 0 , iso-C 11 : 0 , iso-C 11 : 0 3-OH and iso-C 17 : 1 !9c. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. Phylogenetic and physiological analysis indicated that the isolate represents a novel species of the genus Luteimonas, for which the name Luteimonas arsenica sp. nov. is proposed. The type strain is [26][27][28][29][30][31][32][33][34][35] T (=KCTC 42824 T =CCTCC AB 2014326 T ).

Radioactive wastes always contain radioactive substances and a lot of Pb compound and other heavy metals, which severely contaminate soils and groundwater. Thus, search for radiation-resistant microorganisms that are capable of sequestering Pb contaminants from the contaminated sites is urgently needed. However, very few such microorganisms have been found so far. In the present study, we discovered a novel Gram-negative bacterium from the arid Taklamakan desert, which can strongly resist both radiation and Pb(2+). Phylogenetic and phenotypic analysis indicated that this bacterial strain is closely affiliated with Microvirga aerilata, and was thus referred to as Microvirga aerilata LM (=CCTCC AB 208311). We found that M. aerilata LM can effectively accumulate Pb and form intracellular precipitations. It also keeps similar ability to remove Pb(2+) under radioactive stress. Our data suggest that M. aerilata LM may offer an effective and eco-friendly in situ approach to remove soluble Pb contaminants from radioactive wastes.