The Department of Microbiology/Immunology, A. T. Still University of Health Sciences, Kirksville College of Osteopathic Medicine, 800 West Jefferson Street, Kirksville, USA.
Department of Neurobiology, Physiology and Behavior, College of Biological Sciences, University of California, Davis, One Shields Avenue, USA.
J Med Microbiol. 2021 Jun;70(6). doi: 10.1099/jmm.0.001392.
This study describes the identification and partial characterization of persistence-inducing factors (PIFs) from staphylococci. Increases in persisters during mid-log phase growth indicate that quorum-sensing factors might be produced by staphylococci. To identify and partially characterize PIFs from RP62A and SH1000. Others have demonstrated a significant increase in persister numbers during mid-log phase. Inducers of this mid-log increase have yet to be identified in staphylococci. Optical density at 600 nm (OD) was used instead of time to determine when persister numbers increased during logarithmic growth. Concentrated culture filtrates (CCFs) from and were obtained at various ODs and following incubation at 16 h. The CCFs were used to develop a PIF assay. The PIF assay was used to partially characterize PIF from and for sizing of PIF activity, temperature and protease sensitivity and inter-species communications. The optimal ODs for and PIF assays were 2.0 and 0.5, respectively. The highest PIF activity for both species was from CCF following incubation overnight (16 h). ' PIF activity was decreased by storage at 4 C but not at 20 C (16 h), 37 C (1 h) or 100 C (15 min). ' PIF activity was decreased following storage at 4 C (2 weeks) and after boiling at 100 C for 5 min but not after incubation at 37 C (1 h). PIF activity from both species went through a 3000 molecular weight cutoff ultrafilter. Proteinase K treatment of PIF decreased activity but did not decrease the PIF activity of . PIF from did not increase persisters when used to treat cells and nor did PIF from increase persisters when used to treat cells. Attempts to discover PIFs for staphylococci were unsuccessful due to the time-based means used to identify mid-log. Both staphylococcal species produce extracellular, low-molecular-weight inducers of persistence when assayed using an OD -based PIF assay.
这项研究描述了从葡萄球菌中鉴定和部分表征持久性诱导因子 (PIFs)。在对数中期生长过程中，持久性增加表明群体感应因子可能由葡萄球菌产生。为了鉴定和部分表征来自 RP62A 和 SH1000 的 PIFs。其他人已经证明，在对数中期，持久性细胞的数量会显著增加。在葡萄球菌中，尚未鉴定出这种对数中期增加的诱导物。使用吸光度 (OD) 而不是时间来确定对数生长过程中持久性细胞数量增加的时间。从 和 获得不同 OD 和孵育 16 小时后的浓缩培养滤液 (CCF)。使用 CCF 开发 PIF 测定法。使用 PIF 测定法部分表征来自 和 的 PIF，用于测定 PIF 活性、温度和蛋白酶敏感性以及种间通讯的大小。和的最佳 OD 分别为 2.0 和 0.5。两种物种的最高 PIF 活性均来自孵育过夜（16 小时）后的 CCF。在 4°C 下储存会降低 'PIF 活性，但在 20°C（16 小时）、37°C（1 小时）或 100°C（15 分钟）下不会降低。在 4°C 下储存（2 周）和在 100°C 下煮沸 5 分钟后，'PIF 活性降低，但在 37°C（1 小时）孵育后不会降低。两种物种的 PIF 均通过 3000 分子量截止超滤。蛋白激酶处理 'PIF 降低了活性，但未降低 PIF 的活性。当用于处理 细胞时，来自 的 PIF 不会增加持久性细胞，当用于处理 细胞时，来自 的 PIF 也不会增加持久性细胞。由于基于时间的方法用于识别对数中期，因此未能发现葡萄球菌的 PIFs。当使用基于 OD 的 PIF 测定法进行测定时，两种葡萄球菌都产生了细胞外、低分子量的持久性诱导物。
