Intracellular Biosynthesis of Fluorescent CdSe Quantum Dots in Bacillus subtilis: A Strategy to Construct Signaling Bacterial Probes for Visually Detecting Interaction Between Bacillus subtilis and Staphylococcus aureus

• Published in: Microscopy and microanalysis 2016-02, Vol.22 (1), p.13-21
• Main Authors: Yan, Zheng-Yu, Ai, Xiao-Xia, Su, Yi-Long, Liu, Xin-Ying, Shan, Xiao-Hui, Wu, Sheng-Mei
• Format: Article
• Language: English
• Subjects: Antibiotics; Bacillus subtilis; Bacillus subtilis - metabolism; Bacillus subtilis - physiology; Bacteria; Bacterial Adhesion; Biological Applications; Biosynthesis; Cadmium; Cadmium Compounds - metabolism; Fluorescent Dyes - metabolism; Labeling; Mass spectrometry; Microbial Interactions; Probes; Quantum Dots; Raw materials; Selenium Compounds - metabolism; Signal Transduction; Staining and Labeling - methods; Staphylococcus aureus; Staphylococcus aureus - physiology
• ISSN: 1431-9276; 1435-8115
• DOI: 10.1017/S1431927615015548

In this work, fluorescent Bacillus subtilis (B. subtilis) cells were developed as probes for imaging applications and to explore behaviorial interaction between B. subtilis and Staphylococcus aureus (S. aureus). A novel biological strategy of coupling intracellular biochemical reactions for controllable biosynthesis of CdSe quantum dots by living B. subtilis cells was demonstrated, through which highly luminant and photostable fluorescent B. subtilis cells were achieved with good uniformity. With the help of the obtained fluorescent B. subtilis cells probes, S. aureus cells responded to co-cultured B. subtilis and to aggregate. The degree of aggregation was calculated and nonlinearly fitted to a polynomial model. Systematic investigations of their interactions implied that B. subtilis cells inhibit the growth of neighboring S. aureus cells, and this inhibition was affected by both the growth stage and the amount of surrounding B. subtilis cells. Compared to traditional methods of studying bacterial interaction between two species, such as solid culture medium colony observation and imaging mass spectrometry detection, the procedures were more simple, vivid, and photostable due to the efficient fluorescence intralabeling with less influence on the cells’ surface, which might provide a new paradigm for future visualization of microbial behavior.