Shin Eunjung, Noh Hee Seong, Ye Qianying, Lee Sung-Jae
Department of Biology, Kyung Hee University, Seoul, Republic of Korea.
Front Microbiol. 2023 Mar 2;14:1110084. doi: 10.3389/fmicb.2023.1110084. eCollection 2023.
DY59 (formerly DY59) is a radiation-resistant bacterium isolated from soil. From the 3.5 Mb genomic DNA sequence of strain DY59 (December 2014), 31 insertion sequence (IS) elements of six IS families including IS, IS, IS, IS, IS, and IS and five unclassified IS elements were detected. Upon induction of oxidative stress with 80 and 100 mM HO, the unique ISs of the IS family member were actively translocated into a carotenoid biosynthesis gene phytoene desaturase (QR90_10400), resulting in non-pigment phenotypic selection. Therefore, these active transpositions of a specific IS family member were induced by oxidative stress at 80 and 100 mM HO. Furthermore, DY59 exhibited extremely higher MIC values against HO treatment. To explain this phenomenon, qRT-PCR was conducted to assess the expression levels of catalase and three LysR family regulators. Our findings indicated that the IS and IS elements of the IS family were actively transposed into the phytoene desaturase gene by HO treatment replicative transposition. However, high HO resistance did not originate from HO-induced expression of catalase and LysR family regulators.
DY59（原称DY59）是一种从土壤中分离出的抗辐射细菌。从菌株DY59（2014年12月）的3.5 Mb基因组DNA序列中，检测到包括IS、IS、IS、IS、IS和IS在内的6个IS家族的31个插入序列（IS）元件以及5个未分类的IS元件。在用80和100 mM H₂O₂诱导氧化应激时，IS家族成员的独特IS元件会主动转移到类胡萝卜素生物合成基因八氢番茄红素去饱和酶（QR90_10400）中，导致非色素表型选择。因此，特定IS家族成员的这些活跃转座是由80和100 mM H₂O₂的氧化应激诱导的。此外，DY59对H₂O₂处理表现出极高的最低抑菌浓度（MIC）值。为了解释这一现象，进行了qRT-PCR以评估过氧化氢酶和三个LysR家族调节因子的表达水平。我们的研究结果表明，IS家族的IS和IS元件通过H₂O₂处理以复制转座的方式主动转移到八氢番茄红素去饱和酶基因中。然而，高H₂O₂抗性并非源于H₂O₂诱导的过氧化氢酶和LysR家族调节因子的表达。
