• International Journal of Oral Biology
• /
• v.38 no.2
• /
• pp.81-85
• /
• 2013

There are estimated to be about 700 species of bacteria in the oral cavity. Based on epidemiological investigations, some of these strains have been proposed as the pathogens responsible for oral diseases such as dental caries, gingivitis and periodontitis. Since electrolyzed hydrogen-rich water has been shown to have beneficial effects on human immunity, its use has increased. In our study, the antibacterial activity of hydrogen-rich water for oralagainst bacteria associated with oral disease was evaluated. The bacterial strains Streptococcus mutans, Fusobacterium nucleatum, Porphyromonas gingivalis and Tannerella forsythia were cultured in specific growth medium. S. mutans, F. nucleatum and P. gingivalis were soaked to thein both hydrogen water and tap water for 30 sec and then inoculated onto mitis-salivarius agar and brain heart infusion agar including supplemented withvitamin K and hemin, respectively. The numbers of bacterial colonies were then measured after cultivation for 48 hours. In the case of T. forsythia, which does not grow well on agar plates, inoculations into modified new oral spirochete (NOS) broth were performed and growth curve analysis was undertaken every day with a spectrophotometer. Hydrogen water showed antibacterial activity against all four bacterial strains in comparison with tap-water. We conclude from this that hydrogen water may have a positive impact on oral hygiene by helping to remove cariogenic bacteria and periodontopathogens.

• Mycobiology
• /
• v.48 no.5
• /
• pp.392-398
• /
• 2020

This study was conducted to understand the dynamics of microbial communities of soil microorganisms, and their distribution and abundance in the indigenous microorganisms (IMOs) manipulated from humus collected from the forest near the crop field. The soil microorganisms originated from humus and artificially cultured microbial-based soil amendments were characterized by molecular and biochemical analyses. The bacterial population (2 × 10⁶~13 × 10⁶ CFU/g sample) was approximately 100-fold abundant than the fungal population (2 × 10⁴~8 × 10⁴ CFU/g sample). The 16S rDNA and ITS sequence analyses showed that the bacterial and fungal communities in humus and IMOs were mainly composed of Bacillus and Pseudomonas, and Trichoderma and Aspergillus species, respectively. Some of the bacterial isolates from the humus and IMOs showed strong inhibitory activity against soil-borne pathogenic fungi Fusarium oxysporum and Sclerotinia sclerotiorum. These bacteria also showed the siderophore production activity as well as phosphate solubilizing activity, which are requisite traits for biological control of plant pathogenic fungi. These results suggest that humus and IMOs could be a useful resource for sustainable agriculture.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.54 no.3
• /
• pp.280-286
• /
• 2021

This study was performed to screen the antimicrobial activities and proteolytic enzyme stability of the acidified extract of the Blue mussel Mytilus edulis. The acidified extract showed potent antimicrobial activities against Gram-positive bacteria, Bacillus subtilis, and Gram-negative bacteria, Escherichia coli D31, but had no activity against Candida albicans. Treatment of extract with trypsin completely abolished all or significant antibacterial activity against the tested bacteria, but slightly decreased antimicrobial activity against B. subtilis, and treatment of extract with chymotrypsin retained almost antibacterial activity against the tested bacteria except for E. coli D31. To confirm the additional enzyme stability of the extract, antimicrobial activity of the extract was tested after treated with several enzymes. Enzymes treated extract showed potent antimicrobial activity against B. subtilis and its activity was also retained for 5 h after trypsin treatments. Non-proteinaceous materials in the acidified extract also showed strong DNA-binding ability but did not show bacterial membrane permeabilizing ability. All our results indicate that mussel extract might contain the proteinaceous or non-proteinaceous antibacterial materials target not bacterial membrane but intracellular components. These results could be used to develop mussel extract as an additive for the improvement of stability or antimicrobial activity of antibiotics against specific bacteria.

• Journal of Pharmacopuncture
• /
• v.19 no.4
• /
• pp.312-318
• /
• 2016

Objectives: Bacterial resistant infections have become a global health challenge and threaten the society's health. Thus, an urgent need exists to find ways to combat resistant pathogens. One promising approach to overcoming bacterial resistance is the use of herbal products. Green tea catechins, the major green tea polyphenols, show antimicrobial activity against resistant pathogens. The present study aimed to investigate the effect of catechins, green tea extract, and methylxanthines in combination with gentamicin against standard and clinical isolates of Staphylococcus aureus (S. aureus) and the standard strain of Pseudomonas aeruginosa (P. aeruginosa). Methods: The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of different agents against bacterial strains were determined. The interactions of green tea extract, epigallate catechin, epigallocatechin gallate, two types of methylxanthine, caffeine, and theophylline with gentamicin were studied in vitro by using a checkerboard method and calculating the fraction inhibitory concentration index (FICI). Results: The MICs of gentamicin against bacterial strains were in the range of $0.312-320{\mu}g/mL$. The MIC values of both types of catechins were $62.5-250{\mu}g/mL$. Green tea extract showed insufficient antibacterial activity when used alone. Methylxanthines had no intrinsic inhibitory activity against any of the bacterial strains tested. When green tea extract and catechins were combined with gentamicin, the MIC values of gentamicin against the standard strains and a clinical isolate were reduced, and synergistic activities were observed (FICI < 1). A combination of caffeine with gentamicin did not alter the MIC values of gentamicin. Conclusion: The results of the present study revealed that green tea extract and catechins potentiated the antimicrobial action of gentamicin against some clinical isolates of S. aureus and standard P. aeruginosa strains. Therefore, combinations of gentamicin with these natural compounds might be a promising approach to combat microbial resistance.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.15 no.2
• /
• pp.1-19
• /
• 2002

Fifteen herbs used in oral medicine were extracted in ethanol and screened for tooth whitening effect, radical scavenging activity, inhibition of inducible nitric oxide synthase activity and anti-bacterial activity on Streptoccocus mutans. The results are as followed: 1. The tooth whitening effect of toothpaste containing 1 $\%$ ethanol extracts of 15 herbs was tested in brushing method using artificially stained HAT tablet and bovine tooth specimens. Toothpaste containing 1$\%$ of Vucia unijuga, Illicium verum, Angelica dahurica and Piper longum extracts showed tooth whitening effects on both HAT tablet and bovine tooth specimens. But the others did not show a considerable activity. 2. The antioxidant activity of ethanol extracts of 15 herbs was tested using the method of 1,1-diphenyl-2-picryl hydrazyl (DPPH) reactivity. Two ethanol extracts of Cimicifuga heracleifolia and Phyllostachys nigra var. henonis were found to be the most effective on radical scavenging activity. C. heracleifolia and P. nigra var. henonis extracts removed 86$\%$ and 81 $\%$ of DPPH radical at 0.01$\%$, compared with butylated hydroxy toluene as positive control. 3. The inhibition activity of ethanol extracts on nitrate production In RAW264.7 cell stimulated by lipopolysacchride was tested using the Griess reagent. But all extracts did not inhibit nitrate production. 4. The antibacterial activity on Streptoccocus mutans was tested by paper disk method. But no one extract showed any anti - bacterial activity.

• Journal of Wetlands Research
• /
• v.7 no.2
• /
• pp.37-52
• /
• 2005

Vertical distribution of bacterial population and activities were compared between the muddy and sandy sediment of the tidal flat located in southern area of Ganghwa Island. The average of bacterial number and activities in mud flat was slightly higher than that in sand flat. Bacterial number was markedly increased at the sandflat during the investigation period, which seemed to be the result of increase of mud content. The number and activities of microorganisms in mudflat was comparable to that of the mangrove sediments. There was no differences in bacterial number with the depth, but the aminopeptidase activity and bacterial productivity were decreased markedly within 3~5cm depth of sediment due to the availability of carbon sources and molecular oxygen in pore water. The number and activities of microorganisms in mudflat did not correlated with the distribution of benthic microalgae; however, those in sand flat were closely correlated with the distribution of benthic microalgae. The distribution of marsh plant in the mudflat area might be the reason of the difference.

• The Plant Pathology Journal
• /
• v.32 no.5
• /
• pp.431-440
• /
• 2016

In 2004, bacterial spot-causing xanthomonads (BSX) were reclassified into 4 species-Xanthomonas euvesicatoria, X. vesicatoria, X. perforans, and X. gardneri. Bacterial spot disease on pepper plant in Korea is known to be caused by both X. axonopodis pv. vesicatoria and X. vesicatoria. Here, we reidentified the pathogen causing bacterial spots on pepper plant based on the new classification. Accordingly, 72 pathogenic isolates were obtained from the lesions on pepper plants at 42 different locations. All isolates were negative for pectolytic activity. Five isolates were positive for amylolytic activity. All of the Korean pepper isolates had a 32 kDa-protein unique to X. euvesicatoria and had the same band pattern of the rpoB gene as that of X. euvesicatoria and X. perforans as indicated by PCR-restriction fragment length polymorphism analysis. A phylogenetic tree of 16S rDNA sequences showed that all of the Korean pepper plant isolates fit into the same group as did all the reference strains of X. euvesicatoria and X. perforans. A phylogenetic tree of the nucleotide sequences of 3 housekeeping genes-gapA, gyrB, and lepA showed that all of the Korean pepper plant isolates fit into the same group as did all of the references strains of X. euvesicatoria. Based on the phenotypic and genotypic characteristics, we identified the pathogen as X. euvesicatoria. Neither X. vesicatoria, the known pathogen of pepper bacterial spot, nor X. perforans, the known pathogen of tomato plant, was isolated. Thus, we suggest that the pathogen causing bacterial spot disease of pepper plants in Korea is X. euvesicatoria.

• Journal of Microbiology and Biotechnology
• /
• v.24 no.6
• /
• pp.843-853
• /
• 2014

In the context of artificial groundwater recharge, a reactive soil column at pilot-scale (4.5 m depth and 3 m in diameter) fed by treated wastewater was designed to evaluate soil filtration ability. Here, as a part of this project, the impact of treated wastewater filtration on soil bacterial communities and the soil's biological ability for wastewater treatment as well as the relevance of the use of multi-bioindicators were studied as a function of depth and time. Biomass; bacterial 16S rRNA gene diversity fingerprints; potential nitrifying, denitrifying, and sulfate-reducing activities; and functional gene (amo, nir, nar, and dsr) detection were analyzed to highlight the real and potential microbial activity and diversity within the soil column. These bioindicators show that topsoil (0 to 20 cm depth) was the more active and the more impacted by treated wastewater filtration. Nitrification was the main activity in the pilot. No sulfate-reducing activity or dsr genes were detected during the first 6 months of wastewater application. Denitrification was also absent, but genes of denitrifying bacteria were detected, suggesting that the denitrifying process may occur rapidly if adequate chemical conditions are favored within the soil column. Results also underline that a dry period (20 days without any wastewater supply) significantly impacted soil bacterial diversity, leading to a decrease of enzyme activities and biomass. Finally, our work shows that treated wastewater filtration leads to a modification of the bacterial genetic and functional structures in topsoil.

• The Korean Journal of Malacology
• /
• v.32 no.2
• /
• pp.119-125
• /
• 2016

The present study aimed to understand the effects of a ${\beta}$-glucan-added abalone feed (Immuneglu$^{TM}$) on the immune parameters, survival rate, and anti-bacterial activity of the abalone Nordotis discus hannai. During the study, spat and adult abalones were fed 0, 0.1, and 1% of Immuneglu$^{TM}$ mixed with artificial feed for 2 weeks, and their immune parameters, survival rate, and anti-bacterial activity were measured. The results showed that abalones fed on Immuneglu$^{TM}$-added feed showed a higher phagocytic rate, survival rate, and anti-bacterial activity against Vibrio alginolyticus, than those with the control treatment. In addition, the nitric oxide concentration, which indicates an inflammatory response, increased in the treatment group. Our study suggests that Immuneglu$^{TM}$ might be a useful additive for increasing the immunity and survival rates of abalones during mass culture.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.12
• /
• pp.2090-2099
• /
• 2015

Recently, the cardiovascular disease has been widely problematic in humans probably due to fibrin formation via the unbalanced Western style diet. Although direct (human plasmin) and indirect methods (plasminogen activators) have been available, bacterial enzyme methods have been studied because of their cheap and mass production. To detect a novel bacterial fibrinolytic enzyme, 111 bacterial strains with fibrinolytic activity were selected from kimchi. Among them, 14 strains were selected because of their stronger activity than 0.02 U of plasmin. Their 16S rRNA sequence analysis revealed that they belong to Bacillus, Leuconostoc, Propionibacterium, Weissella, Staphylococcus, and Bifidobacterium. The strain B. subtilis ZA400, with the highest fibrinolytic activity, was selected and the gene encoding fibrinolytic enzyme (bsfA) was cloned and expressed in the E. coli overexpression system. The purified enzyme was analyzed with SDS-PAGE, western blot, and MALDI-TOF analyses, showing to be 28.4 kDa. Subsequently, the BsfA was characterized to be stable under various stress conditions such as temperature (4-40oC), metal ions (Mn²⁺, Ca²⁺, K²⁺, and Mg²⁺), and inhibitors (EDTA and SDS), suggesting that BsfA could be a good candidate for development of a novel fibrinolytic enzyme for thrombosis treatment and may even be useful as a new bacterial starter for manufacturing functional fermented foods.