微观水分和养分条件对铜绿假单胞菌噬菌体裂解宿主过程的影响

Effects of Microscopic Water and Nutrient Conditions on the Host Lysis Process of Pseudomonas aeruginosa Phage

为研究不同水分和养分条件下细菌和噬菌体的生长和运移规律、细菌和噬菌体种群互作过程以及其对群落结构的影响和调控机制,通过控制微生物运动平板表面相对水膜厚度研究铜绿假单胞菌PAO1(Pseudomonas aeruginosa PAO1)和铜绿假单胞菌噬菌体PA-27-1(Pseudomonas aeruginosa phage PA-27-1)的互作过程。结果表明,细菌和噬菌体的互作主要受噬菌体裂解细菌、细菌的运动和噬菌体扩散三个因素控制。水分通过调控多孔表面水膜的厚度和连通性来改变细菌在微孔尺度的运动,进而影响微生物在粗糙界面的增殖和生物膜的形成过程以及菌落的形态特征,同时通过影响噬菌体的扩散传播来调节细菌和噬菌体之间的互作机制。细菌与噬菌体自身运动性及个体大小上的不同也导致二者在微观孔隙中增殖(扩散)特征的差异。相对低水膜网络促进了细菌和噬菌体之间的空间隔离,降低了噬菌体有效侵染细菌的概率,从而有利于细菌的增殖。丰富的养分条件有利于细菌生物量的快速繁殖,进而促进噬菌体的增殖。本研究揭示了环境生物膜等微生境中噬菌体和宿主细菌的生长和运移规律,有助于为深入理解土壤噬菌体的时空分布特征与演变规律以及其与土壤细菌之间的互作模式提供理论基础和数据支撑。

【Objective】This study was designed to investigate the growth and migration of bacteria and phages under different water and nutrient conditions,as well as the process and mechanism of the interactions between bacteria and phages.【Method】Using the agar plate,the interaction of Pseudomonas aeruginosa PAO1 and Pseudomonas aeruginosa phage PA-27-1 were performed.【Result】The coexistence of bacteria and phages is mainly affected by phase-induced lysis of bacteria,motility of bacteria and the diffusion of phages.Moisture regulated the relative water film thickness and connectivity on the porous surface of plates.It also affected the movement and proliferation of bacteria,the formation process of biofilms,and morphological characteristics of colonies on the porous interface.Additionally,it regulated the interaction mechanism between bacteria and phages by affecting the spread of phages.Different motility patterns and individual sizes between bacteria and phages also led to differences in their proliferation(diffusion)characteristics in micro-pores.Lower water film thickness and patchy distribution promoted the spatial isolation between bacteria and phages and reduced the probability of phage-reduced lysis,which was important for the proliferation of bacteria.【Conclusion】This study reveals the migration of phages and bacteria in micro-habitats like biofilm and provides a theoretical basis and data support for the temporal and spatial distribution of soil phages,as well as the interaction pattern between soil phages and soil bacteria.