Several medicinal plants are ethnomedically used in Korea as agents for treating infection, anti-inflammation, and pain relief. However, beyond typical inhibitory effects on cell growth, little is known about the potential anti-biofilm activity of these herbs, which may help to prevent cavities and maintain good oral health. This study aimed to investigate the antimicrobial and anti-biofilm activities of the methanol extracts of 37 Korean medicinal plants against dental pathogens and, which synergize their virulence so as to induce the formation of plaque biofilms in the oral cavity. The antimicrobial activities were investigated by broth dilution and disk diffusion assay. The anti-biofilm and antioxidant activities were evaluated based on the inhibitory effect against glucosyltransferase (GTase) and the DPPH assay, respectively. Among 37 herbs, eight plant extracts presented growth and biofilm inhibitory activities against both etiologic bacteria. Among them, the methanol extracts (1.0 mg/ml) from and significantly inhibited the growth of both bacteria by over 76% and over 83% in liquid media, respectively. Minimum inhibitory concentration (MIC) values of these methanol extracts were determined to be 0.5 mg/ml using a disk diffusion assay on solid agar media. Biofilm formation was inhibited by more than 92.4% and 98.0%, respectively, using the same concentration of each extract. The present results demonstrate that the medicinal plants and are potentially useful as antimicrobial and anti-biofilm agents in preventing dental diseases.

Specific tags with defined amino acid residues are widely used to purify or probe target proteins. Interestingly, the tagging system occasionally results in an increase of the recombinant protein expression in vivo. Here, we systematically examined this phenomenon using a poly-histidine (His)-tag fused to N- or C-terminal region of green, red, and blue fluorescent proteins by quantification and uneven distribution in cytoplasm of Escherichia coli. This effect was further supported by the distinct over-expression of several unrelated proteins, such as esterase, neopullulanase, and chloramphenicol acetyltransferase, tagging with the same tag. These results suggest that a poly-His-tag placed at N-terminal region can induce over-expression of recombinant protein via subcellular uneven distribution in vivo.

No abstract

Propionibacterium acnes, newly reclassified as Cutibacterium acnes, is an anaerobic Gram-positive bacterium causing acne, found mainly on the skin. In addition, P. acnes is responsible for inflammation of the gums (gingivitis) and blood vessels, consequently leading to various diseases in the human body. In recent years, the evolution of microorganisms, such as P. acnes, that have become resistant to many commercial antibiotics due to the widespread use of antimicrobial drugs in the treatment of infectious diseases has emerged as a major clinical problem. We here analyzed the potential use of 37 medicinal plant extracts as plausible candidates for treating P. acnes, in terms of total phenolic and flavonoid contents, antioxidants scavenging and antimicrobial activity. Consequently, methanol extracts from 14 medicinal plants showed promising antimicrobial activities against P. acnes. In particular, as the extracts from Chrysosplenium flagelliferum F. and Thuja orientalis L. exhibited distinct antimicrobial activities in both the broth dilution and disc diffusion assay, they could be effectively used as active ingredients for preventing or treating inflammatory periodontal diseases, such as periodontitis.

In the published version of this paper Figure 4 and the figure legend are incorrect. The correct version of Figure 4 and the figure legend is given here:The authors apologise for this error. . His-tag effect on uneven distribution and activity of chloramphenicol acetyltransferase (CAT), neopullulanase (BCN) and esterase 1767 (A) Distinct uneven distribuiton of proteins with N-terminal His-tag were observed by immunofluorescence staining using anti-His-tag antibody. As a negative conrol, unlocalized patterns of mBFP (without His-tag) using anti-mBFP antibody was shown in this figure. All constructs were expressed under the same conditions using the expression vector pTrc99A. (B) Comparison of distrubiton pattern of proteins with N-and C-terminal His-tag, or without tag under the same culture conditions. All immunofluorescent images were observed by using anti-mBFP antibody. Werstern blot was also conducted using the same antibody as a control for protin expression under the same condition. (C) Zymogram assay for esterase 1767 (left pannel) and maximum inhibitory concentration (MIC) assay for CAT (right pannel). For zymogram assay, an aliguot (10 μg) of the crude enzymes was analyzed on a 11% native-PAGE and then stained with α-naphthyl acetate and Fast Blue RR. Lane 1, empty vector; lane 2, 1767; lane 3; His-1767; lane 4, 1767-His. MIC assay showed differences in inhibitory zone against 6 mm paper impregnated with the same concentration of chloramphenicol (10 5 ppm).