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

Abstract

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.

Fungal In Situ Assembly Gives Novel Properties to CdSxSe1–x Quantum Dots for Sensitive Label-Free Detection of Chloramphenicol

“…The incubation time of Na 2 SeO 3 or CdCl 2 was another key factor in CdS x Se 1– x QD biosynthesis. On the basis of previous research, selenite can be transformed to organic selenium or reduced to elemental selenium. Organic selenium, metabolized by microorganisms from selenite, is the precursor for CdS x Se 1– x QD biosynthesis. , Therefore, on the one hand, short Na 2 SeO 3 incubation times did not provide sufficient organic selenium.…”

Bacteria in Heavy Metal Remediation and Nanoparticle Biosynthesis

“…Cell morphology analysis showed the living cells could be effectively labeled by the prepared QDs subsequent to a 48 h coincubation; the produced fluorescent QDs can be deployed as suitable fluorescent dye for broad labeling applications and bioimaging . In another study, fluorescently capable Bacillus subtilis cells could be useful for imaging applications as probes and to investigate behavioral association among Staphylococcus aureu and B. subtiliss . An innovative biological approach has been reported that entails exploiting biochemical reactions intracellularly for manageable biosynthesis of CdSe quantum dots by live B. subtilis cells; a pathway enabled access to photostable fluorescent B. subtilis cells, which were well-luminant with good uniformity.…”

“…Systematic analyses of their correlations indicated that B. subtilis cells inhibited the growth of adjoining S. aureus cells, which was influenced by the amount of surrounding B. subtilis cells and their growth stage. In contrast to traditional methods of examining bacterial interface among two species, namely, imaging mass spectrometry detection and solid culture medium colony observation, the photostable processes were more vivid and simple because of the effective fluorescence intralabeling with minimal impact on the cells’ surface, which may provide a new paradigm for visualization of microbial conduct in the future …”

“…121 In another study, fluorescently capable Bacillus subtilis cells could be useful for imaging applications as probes and to investigate behavioral association among Staphylococcus aureu and B. subtiliss. 122 An innovative biological approach has been reported that entails exploiting biochemical reactions intracellularly for manageable biosynthesis of CdSe quantum dots by live B. subtilis cells; a pathway enabled access to photostable fluorescent B. subtilis cells, which were well-luminant with good uniformity. By applying fluorescently endowed B. subtilis cells probes, S. aureus cells reacted with cocultured B. subtilis, and the ensuing aggregation degree was assessed that nonlinearly matched to a polynomial model.…”

“…In contrast to traditional methods of examining bacterial interface among two species, namely, imaging mass spectrometry detection and solid culture medium colony observation, the photostable processes were more vivid and simple because of the effective fluorescence intralabeling with minimal impact on the cells' surface, which may provide a new paradigm for visualization of microbial conduct in the future. 122 QDs have been synthesized in genetically engineered E. coli via the insertion of foreign genes encoding a CdS connecting peptide demonstrating that genetically engineered bacteria can be applied for their fabrication. The CdS QDs have been efficaciously seceded from the bacteria via two methods, purification with an anion-exchange resin and lysis and freezing−defrosting of cells.…”