National Centre for Aquatic Animal Health, Cochin University of Science and Technology, Fine Arts Avenue, Kochi, Kerala, 682 016, India.
Department of Environmental Studies, Kannur University, Mangattuparamba Campus, Kannur, Kerala, 670 567, India.
Antonie Van Leeuwenhoek. 2021 Jan;114(1):23-35. doi: 10.1007/s10482-020-01490-7. Epub 2020 Nov 23.
Herein we report the isolation of a novel actinomycete, strain MCCB 268, from the sediment sample collected from a high Arctic fjord Kongsfjorden. MCCB 268 showed greater than 97% 16S rRNA gene sequence similarity with those of Pseudonocardia konjuensis LM 157 (98.06%), Pseudonocardia soli NW8-21 (97.22%) Pseudonocardia endophytica YIM 56035 (97.08%) and Pseudonocardia nantongensis KLBMP 1282 (97.34%) showing that the strain should be assigned to the genus Pseudonocardia. DNA-DNA hybridization with Pseudonocardia konjuensis LM 157 showed only 41.5% relatedness to strain MCCB 268. The whole genome of the strain MCCB 268 was sequenced. Whole-genome average nucleotide identity, dDDH (%) and genome tree analysis demonstrated that strain significantly differed from other Pseudonocardia species. The G + C content was 70.5 mol%. MCCB 268 exhibited in vitro cytotoxicity and through bioassay guided fractionation followed by HPLC separation a cytotoxic compound (I) was isolated. The compound (I) was identified as 1-acetyl-β-carboline through NMR spectra and high-resolution mass spectrometry. Compound (I) showed cytotoxicity against lung cancer cell line and mode of anticancer activity was found to be through the induction of apoptosis. Based on the genotypic and phenotypic features, MCCB 268 ought to be classified as a novel species under the genus Pseudonocardia for which the name Pseudonocardia cytotoxica sp. nov. is proposed (= CCUG72333 = JCM32718).
在这里，我们报告了一株新型放线菌 MCCB 268 的分离，该放线菌来自高北极峡湾 Kongsfjorden 的沉积物样本。MCCB 268 的 16S rRNA 基因序列与 Pseudonocardia konjuensis LM 157（98.06%）、Pseudonocardia soli NW8-21（97.22%）、Pseudonocardia endophytica YIM 56035（97.08%）和 Pseudonocardia nantongensis KLBMP 1282（97.34%）的相似度大于 97%，表明该菌株应归属于假诺卡氏菌属。与 Pseudonocardia konjuensis LM 157 的 DNA-DNA 杂交显示与 MCCB 268 菌株的相关性仅为 41.5%。该菌株 MCCB 268 的全基因组进行了测序。全基因组平均核苷酸同一性、dDDH（%）和基因组树分析表明，该菌株与其他假诺卡氏菌种有明显的差异。G+C 含量为 70.5 mol%。MCCB 268 表现出体外细胞毒性，并通过生物测定指导的分级分离和 HPLC 分离，分离出一种细胞毒性化合物（I）。化合物（I）通过 NMR 谱和高分辨率质谱鉴定为 1-乙酰-β-咔啉。化合物（I）对肺癌细胞系表现出细胞毒性，抗癌活性模式被发现是通过诱导细胞凋亡。基于表型和表型特征，MCCB 268 应该被归类为假诺卡氏菌属中的一个新种，命名为 Pseudonocardia cytotoxica sp. nov.（=CCUG72333=JCM32718）。
