International Journal of Systematic and Evolutionary Microbiology (2012), 62, 1744–1749 DOI 10.1099/ijs.0.034132-0 Arenimonas metalli sp. nov., isolated from an iron mine Fang Chen, Zunji Shi and Gejiao Wang Correspondence State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Gejiao Wang Huazhong Agricultural University, Wuhan, 430070, PR China [email protected] A Gram-staining-negative, aerobic, rod-shaped bacterium (CF5-1T) was isolated from Hongshan Iron Mine, Daye City, Hubei province, China. The major cellular fatty acids (.10 %) were iso- C16 : 0, iso-C15 : 0,C16 : 1v7c alcohol and iso-C17 : 1v9c. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The major respiratory quinone was Q-8. The genomic DNA G+C content was 70.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CF5-1T was most closely related to Arenimonas malthae (95.3 % gene sequence similarity), Arenimonas oryziterrae (94.7 %), Arenimonas donghaensis (94.6 %) and Arenimonas composti (94.5 %). A taxonomic study using a polyphasic approach showed that strain CF5-1T represents a novel species of the genus Arenimonas, for which the name Arenimonas metalli sp. nov. is proposed. The type strain is CF5-1T (5CGMCC 1.10787T5KCTC 23460T5CCTCC AB 2010449T). The family Xanthomonadaceae was described by Saddler & characteristics of members of the genus Arenimonas are Bradbury (2005), and although, according to Rule 51b(1) Gram-staining-negative, aerobic, rod-shaped, non-spore- of the Bacteriological Code (1990 Revision; Lapage et al., forming, oxidase-positive, non-indole-producing, non- 1992), the name of this family is illegitimate because it nitrate-reducing, containing iso-C16 : 0, iso-C15 : 0 and iso- contains the genus Lysobacter, many new strains have still C17 : 1v9c as the major fatty acids, phosphatidylglycerol been classified within this family (Johansen et al., 2005; Jin (PG) and phosphatidylethanolamine (PE) as the major et al., 2007; Aslam et al., 2009; Ten et al., 2009; Lee et al., polar lipids, Q-8 as the major respiratory quinone, and 2011). To date, there are 20 genera in the family Xantho- possessing relatively high DNA G+C content (65.0– monadaceae, including several genera that were established 70.8 mol%) (Kwon et al., 2007; Young et al., 2007; Jin in recent years, Arenimonas (Kwon et al., 2007), Igna- et al., 2007; Aslam et al., 2009). Of these characteristics, tzschineria (To´th et al., 2007), Wohlfahrtiimonas (To´th Gram-staining-negative, aerobic, rod-shaped, non-spore- et al., 2008), Rudaea (Weon et al., 2009) and Pseudofulvi- forming and Q-8 as the major respiratory quinone are also monas (Ka¨mpfer et al., 2010). The genus Arenimonas was common among the genera within the family Xanthomo- first proposed by Kwon et al. (2007). At the time of writing, nadaceae (Busse et al., 2002; Lee et al., 2005; Yoon et al., the genus Arenimonas contained only four species with 2006; To´th et al., 2008). validly published names, Arenimonas donghaensis (type In order to investigate culturable bacteria from an iron mine species) (Kwon et al., 2007), Arenimonas malthae (Young environment, iron mining powder was collected from Hong- et al., 2007), Arenimonas oryziterrae (Aslam et al., 2009) shan Iron Mine (about 100 m underground, 30u 049 38.770 N, and Arenimonas composti (Aslam et al., 2009), isolated 114u 579 24.070 E), Daye City, Hubei Province, China. The from seashore sand, oil-contaminated soil, the rice rhizo- pH (in water) of the iron mining powder was 7.85. The total sphere and compost, respectively. The species Arenimonas C, N, P, S and Fe concentrations were 11.61, 0.21, 0.13, 6.37, composti (Aslam et al., 2009) was previously classified as 308.84 g kg21, respectively, as determined by atomic ab- Aspromonas composti (Jin et al., 2007). The common sorption spectroscopy (AAS). Bacterial isolation was per- formed using R2A (Difco) agar plates incubated at 28 uC for Abbreviations: DPG, Diphosphatidylglycerol; MIC, minimum inhibitory 7 days. In this study, we report the taxonomic classification concentration; PE, phosphatidylethanolamine; PG, phosphatidylglycerol; of strain CF5-1T. PL, unknown phospholipids; PME, phosphatidylmonomethylethanol- amine. For analyses of morphological, physiological and biochem- T The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene ical characteristics, strain CF5-1 and four members of the sequence of strain CF5-1T is HQ698842. genus Arenimonas, A. malthae CCUG 53596T, A. oryziterrae T T Three supplementary figures are available with the online version of this KCTC 22247 , A. donghaensis DSM 18148 and A. composti T paper. KCTC 12666 , were cultivated on R2A agar or broth and Downloaded from www.microbiologyresearch.org by 1744 034132 G 2012 IUMS Printed in Great Britain IP: 220.249.99.182 On: Tue, 20 Oct 2015 02:15:33 Arenimonas metalli sp. nov. incubated at 28 uC for 3 days unless otherwise stated. Cell sequences available in NCBI GenBank database using the morphology and the presence of flagella were observed BLASTN program. The similarities were calculated using the using a transmission electron microscope with cells grown NCBI alignment and EzTaxon program (Chun et al., 2007). for 1 day at 28 uC in half-strength R2A broth (Aslam et al., The 16S rRNA gene sequence of strain CF5-1T was aligned 2009). Colony morphology was observed on R2A agar. with the four type strains of members of the genus Areni- Gram-staining was performed as described by Dussault monas, some representatives of the family Xanthomo- (1955) combined with the KOH lysis method (Ryu, 1938). nadaceae and Escherichia coli ATCC 11775T (used as an Growth at different temperatures (0, 4, 15, 20, 28, 37 and outgroup) using the CLUSTAL_X program (Thompson et al., 42 uC) was tested on R2A agar for 2 weeks. Salt tolerance 1997). A neighbour-joining (Saitou & Nei, 1987) tree and a was tested in R2A broth supplemented with 0–5 % (w/v) maximum-parsimony (Fitch, 1971) tree were constructed NaCl incubated at 28 uC for 7 days. Growth at pH 4–10 using MEGA 4.0 (Tamura et al., 2007). A maximum-likeli- (using increments of 1 pH unit) was assessed after hood tree was generated using the PHYML online web server incubation in R2A broth at 28 uC for 7 days. The R2A (Guindon et al., 2005). Bootstrap values were calculated broth was adjusted to initial pH value with citrate/ based on 1000 replications (Felsenstein, 1985) in order to phosphate buffer or Tris/hydrochloride buffer (Breznak & obtain the confidence level of the branches. Costilow, 1994). Anaerobic growth was determined by + incubation in an anaerobic chamber (Mitsubishi Gas The DNA G C content was determined by HPLC as described by Mesbah et al. (1989). For whole-cell fatty acid Chemical Co, Inc.) for 2 weeks. Motility tests used R2A T broth with 0.3 % agar and stab inoculation. Growth on analysis, strain CF5-1 and the four reference strains were nutrient agar, 1.0 % (w/v) trypticase soy broth (TSB) plus grown in R2A broth at 28 uC until they reached exponential 1.5 % agar, MacConkey agar, full-strength trypticase soy phase and were then analysed by GC (6890; Hewlett agar (TSA) and Luria–Bertani (LB) agar (all from Difco) Packard), according to the instructions of the Sherlock were investigated. Nitrate reduction was tested by the Microbial Identification System (MIDI Sherlock version 4.5, method described by La´nyı´ (1987). Tests to determine MIDI database TSBA40 4.10) (Kroppenstedt, 1985; Sasser, indole production, catalase and oxidase activities, and 1990). The respiratory quinones were extracted and hydrolysis of DNA were performed as described by Smibert identified by HPLC as described by Xie & Yokota (2003). & Krieg (1994). Hydrolysis of casein, aesculin, gelatin, L- Polar lipids were determined by two-dimensional TLC as tyrosine, urea, starch, Tween 80 and CM-cellulose were described by Tindall (1990) and Ventosa et al. (1993). performed as described by Cowan & Steel (1965). Acid Strain CF5-1T was Gram-staining-negative, aerobic, non- production from various carbohydrates was determined motile and non-spore-forming. A transmission electron according to Hugh & Leifson (1953). Antibiotic-suscept- micrograph showed that the cell morphology was rod- ibility tests were performed by spreading bacterial suspen- shaped without flagella (Fig. S1, available in IJSEM online). sions on culture plates and applying filter-paper discs Colonies on R2A agar plates were smooth, circular, containing different antibiotics. Antibiotic susceptibility yellowish to creamy white and 1–2 mm in diameter. The was confirmed when an inhibition zone diameter was strain grew well on R2A agar, nutrient agar, 1.0 % (w/v) above 10 mm (Hangzhou Microbial Reagent Co., Ltd). TSB plus 1.5 % agar, full-strength TSA and LB agar, but did Other physiological/biochemical properties and enzyme not grow on MacConkey agar. Detailed results of the activities were examined using API 20NE and API ZYM polyphasic characteristics of strain CF5-1T are given in the systems (bioMe´rieux) according to the manufacturer’s species description. The main differences in phenotypic instructions. The single carbon substrate utilizations were characteristics between strain CF5-1T and the four refer- determined using the GN2 MicroPlate (Biolog) according ence species of the genus Arenimonas are shown in Table 1. to the manufacturer’s instructions. All strains were culti- In addition, the MICs of strain CF5-1T were 0.1, 0.1, 0.1, + + + + vated on R2A agar and incubated at 28 uC for 3 days. 0.3, 0.3, 0.4, 0.5 and 0.5 mM for Sb3 ,As3 ,Zn2 ,Cu2 , + + + + The minimum inhibitory concentration (MIC), defined as Ni2 ,Co2 ,Cr6 and Fe3 , respectively. the lowest metal(loid) concentration that completely T T The 1506 bp 16S rRNA gene sequence of strain CF5-1 was inhibited the growth of strain CF5-1 , was determined as closely related to A.