Related Experiment Video
Updated: Jun 10, 2026
Rose Bengal-Mediated Photodynamic Therapy to Inhibit Candida albicans
Published on: March 24, 2022
Photodynamic therapy with rose bengal induces GroEL expression in Streptococcus mutans
Mayte Bolean1, Tony de Paiva Paulino, Geraldo Thedei
1Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, FFCLRP-USP, Ribeirão Preto, SP, Brasil.
Unlabelled:
Heat-shock proteins (HSPs) are indicative of stressing conditions that may affect cell viability. In Streptococcus mutans, acid stress induces high levels of GroEL, an HSP, in addition to metabolic alterations, as shown by proteomic analysis.
Objective:
We tested whether the expression of GroEL by S. mutans was enhanced after photodynamic therapy (PDT) with rose bengal.
Methods:
S. mutans was grown in complete medium supplemented with 50 mmol/L glucose. The test conditions used were as follows: Rose bengal (0.1 micromol/L) with and without light treatment (500 mJ/cm(2)), light treatment alone, and 1 mol/L NaCl (as a stress condition). The extracellular pH of bacteria was monitored; HSP expression was assayed with Western blot, and possible DNA damage analyzed.
Results:
Higher HSP expression was detected in bacteria after PDT treatment as compared with light or dye alone (negative controls). The expression of HSP after PDT was similar to that induced by osmotic stress. No DNA degradation was observed after PDT of S. mutans.
Conclusions:
PDT may cause effects similar to those of other stressing conditions in S. mutans, and cell death induced by this treatment reflects its incapacity to protect itself sufficiently against the deleterious effects of PDT with Rose bengal.
