Mechanism of static magnetic field influencing morphogenesis of Flavobacterium sp. m1-14

The biological effects of static magnetic fields (SMF) have long been a research hotspot in academia. While the impact of magnetic fields on microbial morphogenesis is closely linked to microbial fermentation efficiency, the specific mechanism remains incompletely elucidated. In this study, the vitamin K₂-producing strain Flavobacterium sp. m1–14 was exposed to a static magnetic field of up to 9 Tesla (T) for 24 h. It was observed that the bacterial cells shrank, showing an overall decreasing trend in size. The length, width, and aspect ratio decreased by approximately 25.27 %, 14.28 %, and 17.95 %, respectively. Furthermore, the physiological and biochemical properties of the bacteria underwent significant changes. Specifically, the cell membrane permeability increased by approximately 6.2 %; the activities of Na⁺-K⁺-ATPase and Ca²⁺-Mg²⁺-ATPase decreased by about 57.5 % and 34.7 %, respectively; and the membrane potential decreased significantly. In addition, intracellular ATP levels decreased by approximately 12 %, a change directly attributed to impaired ATP metabolism. Investigations into the key morphological regulatory genes mreB and ftsZ revealed that their transcription levels were unregulated by 190 % and 38 %, respectively—likely a stress response induced by cellular energy deficiency. Under conditions of high mreB and ftsZ expression, cells reduce their size to minimize metabolic loss, thereby adapting to extreme environments.