Environmental Stress-Induced Bacterial Lysis and Extracellular DNA Release Contribute to Campylobacter jejuni Biofilm Formation

• Published in: Applied and environmental microbiology 2018-03, Vol.84 (5)
• Main Authors: Feng, Jinsong, Ma, Lina, Nie, Jiatong, Konkel, Michael E, Lu, Xiaonan
• Format: Article
• Language: English
• Subjects: Bacteria; Bacterial Adhesion - physiology; Biodegradation; Biofilms; Campylobacter; Campylobacter jejuni; Campylobacter jejuni - genetics; Campylobacter jejuni - physiology; Clonal deletion; Deoxyribonuclease; Deoxyribonucleic acid; DNA; DNA, Bacterial - genetics; DNA, Bacterial - metabolism; Environmental conditions; Environmental DNA; Environmental stress; Flagella; Food Microbiology; Gene deletion; Genomics; Lysis; RecA protein; Salmonella; Stress, Physiological; Stresses
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/AEM.02068-17

is a microaerophilic bacterium and is believed to persist in a biofilm to antagonize environmental stress. This study investigated the influence of environmental conditions on the formation of biofilm. We report an extracellular DNA (eDNA)-mediated mechanism of biofilm formation in response to aerobic and starvation stress. The eDNA was determined to represent a major form of constitutional material of biofilms and to be closely associated with bacterial lysis. Deletion mutation of the stress response genes and enhanced the aerobic influence by stimulating lysis and increasing eDNA release. Flagella were also involved in biofilm formation but mainly contributed to attachment rather than induction of lysis. The addition of genomic DNA from either or resulted in a concentration-dependent stimulation effect on biofilm formation, but the effect was not due to forming a precoating DNA layer. Enzymatic degradation of DNA by DNase I disrupted biofilm. In a dual-species biofilm, eDNA allocated and at distinct spatial locations that protect from oxygen stress. Our findings demonstrated an essential role and multiple functions of eDNA in biofilm formation of , including facilitating initial attachment, establishing and maintaining biofilm, and allocating bacterial cells. is a major cause of foodborne illness worldwide. In the natural environment, the growth of is greatly inhibited by various forms of environmental stress, such as aerobic stress and starvation stress. Biofilm formation can facilitate the distribution of by enabling the survival of this fragile microorganism under unfavorable conditions. However, the mechanism of biofilm formation in response to environmental stress has been investigated only partially. The significance of our research is in identifying extracellular DNA released by bacterial lysis as a major form of constitution material that mediates the formation of biofilm in response to environmental stress, which enhances our understanding of the formation mechanism of biofilm. This knowledge can aid the development of intervention strategies to limit the distribution of .