Patwardhan Rajashree Bhalchandra, Dhakephalkar Prashant Kamalakar, Chopade Balu Ananda, Dhavale Dilip D, Bhonde Ramesh R
Department of Microbiology, Haribhai V. Desai College of Arts, Science and Commerce, Pune University, Pune, India.
Bioenergy Group, Agharkar Research Institute, Pune, India.
Front Microbiol. 2018 Nov 8;9:2618. doi: 10.3389/fmicb.2018.02618. eCollection 2018.
Plasmid curing is the process of obviating the plasmid encoded functions such as antibiotic resistance, virulence, degradation of aromatic compounds, etc. in bacteria. Several plasmid curing agents have been reported in literature, however, no plasmid curing agent can eliminate all plasmids from different hosts. Hence, there is always a need for novel plasmid curing agents that can be effectively used for reversal of plasmid encoded functions such as virulence, antibiotic resistance, etc. In the present study, an active principle responsible for the plasmid curing activity was purified from roots of by bioassay guided fractionation and identified as 2-hydroxy-1,4-naphthoquinone (lawsone), on the basis of spectral and analytical data such as NMR, GCMS, FTIR. Plasmid curing activity of lawsone was observed against reference as well as wild plasmids (pBR322, pRK2013, R136, pUPI281, and pUPI282) residing in a range of hosts. Curing of plasmid was confirmed by agarose gel electrophoresis. MICs of antibiotics against A24 (pUPI281) and (pRK2013) decreased significantly in presence of lawsone suggesting synergy between lawsone and antibiotics. Lawsone also inhibited transfer of plasmid pRK2013 to either by transformation or conjugation. Viability assays (MTT) revealed that lawsone was not toxic to mammalian cells. Thus, the present investigation has revealed lawsone as an effective plasmid curing agent capable of suppressing development and spread of antibiotic resistance. Further, lawsone has important application in basic research to identify phenotypes encoded by the plasmids in plasmid curing experiments. To the best of our knowledge this is the first report of plasmid curing activity of lawsone isolated from roots of
质粒消除是消除细菌中质粒编码功能（如抗生素抗性、毒力、芳香族化合物降解等）的过程。文献中已报道了几种质粒消除剂，然而，没有一种质粒消除剂能从不同宿主中消除所有质粒。因此，一直需要新型质粒消除剂，其可有效用于逆转质粒编码的功能，如毒力、抗生素抗性等。在本研究中，通过生物测定引导分级分离从[植物名称]根中纯化出一种负责质粒消除活性的活性成分，并根据NMR、GCMS、FTIR等光谱和分析数据鉴定为2-羟基-1,4-萘醌（胡桃醌）。观察到胡桃醌对存在于一系列宿主中的参考质粒以及野生质粒（pBR322、pRK2013、R136、pUPI281和pUPI282）具有质粒消除活性。通过琼脂糖凝胶电泳确认了质粒的消除。在存在胡桃醌的情况下，抗生素对[细菌名称]A24（pUPI281）和[细菌名称]（pRK2013）的最低抑菌浓度显著降低，表明胡桃醌与抗生素之间具有协同作用。胡桃醌还通过转化或接合抑制质粒pRK2013向[细菌名称]的转移。活力测定（MTT）表明胡桃醌对哺乳动物细胞无毒。因此，本研究揭示了胡桃醌是一种有效的质粒消除剂，能够抑制抗生素抗性的发展和传播。此外，胡桃醌在基础研究中具有重要应用，可在质粒消除实验中鉴定由质粒编码的表型。据我们所知，这是从[植物名称]根中分离出的胡桃醌具有质粒消除活性的首次报道。
