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- Enterococcus Phage vB_EfaS_HEf13 as an Anti-Biofilm Agent Against Enterococcus faecalis.
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Dongwook Lee, Jintaek Im, A Reum Kim, Woohyung Jun, Cheol-Heui Yun, Seung Hyun Han
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J. Microbiol. 2024;62(8):683-693. Published online June 27, 2024
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DOI: https://doi.org/10.1007/s12275-024-00150-z
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Abstract
- Enterococcus faecalis is a Gram-positive bacterium that is frequently found in the periapical lesion of patients with apical periodontitis. Its biofilm formation in root canal is closely related to the development of refractory apical periodontitis by providing increased resistance to endodontic treatments.
Phage therapy has recently been considered as an efficient therapeutic strategy in controlling various periodontal pathogens. We previously demonstrated the bactericidal capacities of Enterococcus phage vB_EfaS_HEf13 (phage HEf13) against clinically-isolated E. faecalis strains. Here, we investigated whether phage HEf13 affects biofilm formation and pre-formed biofilm of clinically-isolated E.
faecalis, and its combinatory effect with endodontic treatments, including chlorhexidine (CHX) and penicillin. The phage HEf13 inhibited biofilm formation and disrupted pre-formed biofilms of E. faecalis in a dose- and time-dependent manner. Interestingly, phage HEf13 destroyed E. faecalis biofilm exopolysaccharide (EPS), which is known to be a major component of bacterial biofilm. Furthermore, combined treatment of phage HEf13 with CHX or penicillin more potently inhibited biofilm formation and disrupted pre-formed biofilm than either treatment alone. Confocal laser scanning microscopic examination demonstrated that these additive effects of the combination treatments on disruption of pre-formed biofilm are mediated by relatively enhanced reduction in thickness distribution and biomass of biofilm. Collectively, our results suggest that the effect of phage HEf13 on E. faecalis biofilm is mediated by its EPS-degrading property, and its combination with endodontic treatments more potently suppresses E. faecalis biofilm, implying that phage HEf13 has potential to be used as a combination therapy against E. faecalis infections.
- Alcohol dehydrogenase 1 and NAD(H)-linked methylglyoxal oxidoreductase reciprocally regulate glutathione-dependent enzyme activities in Candida albicans
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Sa-Ouk Kang , Min-Kyu Kwak
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J. Microbiol. 2021;59(1):76-91. Published online December 23, 2020
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DOI: https://doi.org/10.1007/s12275-021-0552-7
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Abstract
- Glutathione reductase (Glr1) activity controls cellular glutathione
and reactive oxygen species (ROS). We previously
demonstrated two predominant methylglyoxal scavengers–
NAD(H)-linked methylglyoxal oxidoreductase (Mgd1) and
alcohol dehydrogenase 1 (Adh1)–in glutathione-depleted γ-
glutamyl cysteinyl synthetase-disrupted Candida albicans.
However, experimental evidence for Candida pathophysiology
lacking the enzyme activities of Mgd1 and Adh1 on glutathione-
dependent redox regulation remains unclear. Herein,
we have aimed to demonstrate that glutathione-dependent
enzyme activities coupled with cellular ROS changes is regulated
by methylglyoxal accumulation in Δmgd1/Δadh1 double
disruptants. Δmgd1/Δadh1 showed severe growth defects
and G1-phase cell cycle arrest. The observed complementary
and reciprocal methylglyoxal-oxidizing and methylglyoxalreducing
activities between Δmgd1 and Δadh1 were not always
exhibited in Δmgd1/Δadh1. Although intracellular accumulation
of methylglyoxal and pyruvate was shown in all
disruptants, to a greater or lesser degree, methylglyoxal was
particularly accumulated in the Δmgd1/Δadh1 double disruptant.
While cellular ROS significantly increased in Δmgd1
and Δadh1 as compared to the wild-type, Δmgd1/Δadh1 underwent
a decrease in ROS in contrast to Δadh1. Despite the
experimental findings underlining the importance of the
undergoing unbalanced redox state of Δmgd1/Δadh1, glutathione-
independent antioxidative enzyme activities did not
change during proliferation and filamentation. Contrary to
the significantly lowered glutathione content and Glr1 enzyme
activity, the activity staining-based glutathione peroxidase
activities concomitantly increased in this mutant. Additionally,
the enhanced GLR1 transcript supported our results in
Δmgd1/Δadh1, indicating that deficiencies of both Adh1 and
Mgd1 activities stimulate specific glutathione-dependent enzyme
activities. This suggests that glutathione-dependent redox
regulation is evidently linked to C. albicans pathogenicity
under the control of methylglyoxal-scavenging activities.
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