School of Biological Sciences, University of Oklahoma, Norman, Oklahoma, USA.
Laboratories of Molecular Anthropology and Microbiome Research, University of Oklahoma, Norman, Oklahoma, USA.
Int J Syst Evol Microbiol. 2024 Aug;74(8). doi: 10.1099/ijsem.0.006506.
Four methane-oxidizing bacteria, designated as strains WSC-6, WSC-7, SURF-1, and SURF-2, were isolated from Saddle Mountain Creek in southwestern Oklahoma, USA, and the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. The strains were Gram-negative, motile, short rods that possessed intracytoplasmic membranes characteristic of type I methanotrophs. All four strains were oxidase-negative and weakly catalase-positive. Colonies ranged from pale pink to orange in colour. Methane and methanol were the only compounds that could serve as carbon and energy sources for growth. Strains WSC-6 and WSC-7 grew optimally at lower temperatures (25 and 20 °C, respectively) compared to strains SURF-1 and SURF-2 (40 °C). Strains WSC-6 and SURF-2 were neutrophilic (optimal pH of 7.5 and 7.3, respectively), while strains WSC-7 and SURF-1 were slightly alkaliphilic, with an optimal pH of 8.8. The strains grew best in media amended with ≤0.5% NaCl. The major cellular fatty acids were C, C 8, C 7, and C 5. The DNA G+C content ranged from 51.5 to 56.0 mol%. Phylogenetic analyses indicated that the strains belonged to the genus , with each exhibiting 98.6-99.6% 16S rRNA gene sequence similarity to closely related strains. Genome-wide estimates of relatedness (84.5-88.4% average nucleotide identity, 85.8-92.4% average amino acid identity and 27.4-35.0% digital DNA-DNA hybridization) fell below established thresholds for species delineation. Based on these combined results, we propose to classify these strains as representing novel species of the genus , for which the names (type strain WSC-6=ATCC TSD-251=DSM 112293), (type strain WSC-7=ATCC TSD-252=DSM 112281), (type strain SURF-1=ATCC TSD-253=DSM 112282), and (type strain SURF-2=ATCC TSD-254=DSM 112283) are proposed.
从美国俄克拉荷马州西南部的马鞍山溪和南达科他州铅矿的桑福德地下研究设施（SURF）中分离到四株甲烷氧化细菌，分别命名为菌株 WSC-6、WSC-7、SURF-1 和 SURF-2。这些菌株革兰氏阴性，运动，短杆状，具有Ⅰ型甲烷营养菌特有的胞内膜。四株菌均为氧化酶阴性，过氧化氢酶弱阳性。菌落颜色从淡粉色到橙色不等。甲烷和甲醇是唯一可作为生长碳源和能源的化合物。与菌株 SURF-1 和 SURF-2（40°C）相比，菌株 WSC-6 和 WSC-7 的最佳生长温度较低（分别为 25°C 和 20°C）。菌株 WSC-6 和 SURF-2 为嗜中性（最佳 pH 值分别为 7.5 和 7.3），而菌株 WSC-7 和 SURF-1 为弱嗜碱性，最佳 pH 值为 8.8。菌株在添加 ≤0.5%NaCl 的培养基中生长最好。主要细胞脂肪酸为 C、C 8、C 7 和 C 5。DNA G+C 含量范围为 51.5-56.0mol%。系统发育分析表明，这些菌株属于 属，与密切相关的菌株的 16S rRNA 基因序列相似性为 98.6-99.6%。全基因组估计的相关性（平均核苷酸同一性 84.5-88.4%，平均氨基酸同一性 85.8-92.4%和数字 DNA-DNA 杂交率 27.4-35.0%）低于种系划分的既定阈值。基于这些综合结果，我们建议将这些菌株归类为代表属的新种，其名称分别为 （模式菌株 WSC-6=ATCC TSD-251=DSM 112293）、 （模式菌株 WSC-7=ATCC TSD-252=DSM 112281）、 （模式菌株 SURF-1=ATCC TSD-253=DSM 112282）和 （模式菌株 SURF-2=ATCC TSD-254=DSM 112283）。
