Dr. Yin Ye
Wuyi University, China
Title: An ecological-competition based therapy to inhibit prophage induction
Abstract:
Electroactive biofilm (EAB) is the core part of bioelectrochemical system (BES). The metabolic activity of EAB directly determines the performance of BES in wastewater treatment, environmental pollution remediation, green and clean energy exploitation. Therefore, maintaining the metabolic activity of EAB is critical for the continued proper operation of BES. Geobacter are the model electroactive microorganisms in EAB study and can form EAB with the strongest electrogenic capacity. However, the metabolic activity of Geobacter EAB gradually decreased due to the dead cells accumulated within. Previous studies have speculated that the decay of EAB may be caused by the diffusion limitation or redox gradient dissipation, but these conjectures can only explain the inner or outer layer of EAB decay. In most cases, EAB decay occurred throughout the whole EAB, even happened at the early stage of EAB formation. Therefore, the true cause of EAB decay remains a mystery. Bacteriophage is the natural enemy of bacteria, one of the most important factors causing bacterial death, and can destroy or lyse bacteria formed biofilm. Genome-based studies have revealed that prophage sequences were widespread in Geobacter genomes. At present, research on Geobacter phage is relatively lagging behind. It is not known if Geobacter prophages could be activated to enter the lytic cycle to produce phage particles during EAB formation and whether phages involved in the decay of Geobacter EAB. Therefore, in this study, the prophages of G. sulfurreducens were thoroughly investigated. G. sulfurreducens was found to own prophages that could be activated, prophage induction was confirmed to cause the decay of G. sulfurreducens EAB.
There are many methods established to inhibit prophage induction. As we all know, phages have both lysogenic and lytic life stages. The lysogenic stage can have neutral or beneficial effects on the host cell, but the lytic stage only has detrimental effects. Thus, blocking the lysogenic to lytic transition of prophages will prevent cell lysis triggered by phages. For example, the genetically activating and controlling repressor protein or other cleavable repressors of host cell impedes prophages from switching to the lytic cycle; addition of protease inhibitors such as antipain inhibits prophage induction in microbes by blocking proteolytic inactivation of repressors; increasing the amount of signal peptides promotes the ability of phages to commit to the lysogenic cycle. However, these methods are only exclusive to some microbes and, to an extent, harm microbes in other physiological aspects. Herein, we report that introducing a competitive species of Geobacter uraniireducens suspended prophage induction in G. sulfurreducens and thereby rejuvenated the decayed G. sulfurreducens EAB. The addition of G. uraniireducens significantly affected the expression of metabolism- and stress response system-related genes and in particular suppressed the induction of phage-related genes. The interspecies ecological competition exerted by G. uraniireducens suppressed prophage induction. Our findings not only reveal a novel strategy to rejuvenate decayed EAB, which is significant for the sustainability of BES, but also provide new knowledge for understanding phage-host interactions from an ecological perspective, with implications for developing therapies to defend against phage attack.
Biography:
Yin Ye, Ph.D., is a faculty at Wuyi University and a supervisor for master's candidates. Her research primarily focuses on the interactions between bacteriophages and electroactive hosts, microbial extracellular electron transfer, and microbial nanowires. She has presided over several research projects, including the National Youth Science Foundation Project (Category C), the Key Project of the Fujian Provincial Education Department, and the Fujian Provincial Young Scientist Training Program. In recent years, she has published over 10 papers in journals such as The ISME Journal, Environmental Science & Technology, ISME Communications, mBio, and Acta Pedologica Sinica, and has been granted two national invention patents. With extensive knowledge and research experience in bacteriophage-electroactive host interactions, microbial extracellular electron transfer, and microbial nanowires, her main achievements and contributions are summarized as follows:
① Revealed that prophage induction in Geobacter leads to the decay of electroactive biofilms; proposed methods to inhibit prophage induction to restore the metabolic activity and redox activity of Geobacter electroactive biofilms; reviewed strategies for enhancing the performance of electroactive biofilms in bioelectrochemical systems (Environmental Science & Technology, 2023; The ISME Journal, 2024; Chinese Bulletin of Life Sciences, 2024).
② Demonstrated that Clostridium achieves extracellular electron transfer by forming chimeras with Geobacter; uncovered novel mechanisms of extracellular electron transfer in Geobacter mediated by membrane vesicles, riboflavin, and cytochromes (ISME Communications, 2024; Environmental Science & Technology Letters, 2019；Environmental Microbiology, 2020).
③ Investigated the molecular evolution of pili in Geobacter; elucidated the functions of pili, OmcZ, and OmcS nanowires in electroactive biofilms; reviewed the understanding of the structure and function of nanowires and systematically analyzed the dispute about the nature of microbial nanowires (Molecular Microbiology, 2020; mBio, 2022; Acta Pedologica Sinica, 2024).