A new thiopeptide (micrococcin P3, 1) and a known one (micrococcin P1, 2) were isolated from the culture broth of a marine-derived strain of Bacillus stratosphericus. The structures of both compounds were elucidated using spectroscopic methods, including extensive 1D and 2D NMR analysis, high resolution mass spectrometry (HRMS), and tandem mass spectrometry. Both compounds exhibited potent antibacterial activities against Gram-positive strains with minimum inhibitory concentration (MIC) values of 0.05−0.8 μg/mL and did not show cytotoxicity in the MTT assay up to a concentration of 10 μM. This study adds a new promising member, micrococcin P3, to the family of thiopeptide antibiotics, which shows potential for the development of new antibiotics targeting Gram-positive bacteria.

中文翻译：

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一种新的硫肽抗生素，微球菌素 P3，来自海洋衍生的平流球芽孢杆菌菌株

一种新的硫肽（微球菌素 P3, 1）和一种已知的硫肽（微球菌素 P1, 2）从一种海洋衍生的平流球芽孢杆菌菌株的培养液中分离出来。使用光谱方法阐明了两种化合物的结构，包括广泛的 1D 和 2D NMR 分析、高分辨率质谱 (HRMS) 和串联质谱。两种化合物均对革兰氏阳性菌株表现出有效的抗菌活性，最小抑菌浓度 (MIC) 值为 0.05-0.8 μg/mL，并且在 MTT 测定中直到 10 μM 的浓度都没有显示出细胞毒性。这项研究为硫肽抗生素家族增加了一个新的有希望的成员——微球菌素 P3，这显示了开发针对革兰氏阳性菌的新型抗生素的潜力。