• 대한의생명과학회지
• /
• 제29권2호
• /
• pp.88-94
• /
• 2023

In oriental medicine, the fruit of Actinidia polygama has long been used to alleviate the symptoms of gout, arthritis, and inflammation. In this study, it was to designed to analyze the antibacterial activity of A. polygama ethanol extract (APEE) against Streptococcus mutans, one of the major strains for dental caries, and Porphyromonas gingivalis, one of the critical strains for periodontal disease. The antibacterial activity of APEE was analyzed by disk diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays. In addition, it was also analyzed the inhibitory effect of APEE on bacterial growth and biofilm formation against both oral pathogens. APEE exhibited its antibacterial effect through the inhibited bacterial diffusion as well as low concentration of MIC and MBC. In addition, APEE significantly inhibited not only bacterial growth but also biofilm formation in a dose-dependent manner. Consequently, APEE showed potent antibacterial activity against both S. mutans and P. gingivalis, which indicates that APEE might be used as a potential antibacterial material for the improvement of oral healthcare.

• 한국자기공명학회논문지
• /
• 제15권1호
• /
• pp.1-13
• /
• 2011

9Pbw2 is a 9-mer analog of protaetiamycine derived from the larvae of the beetle Protaetia brevitarsis. Previously, we designed four 9-mer peptide analogues to optimize the balance between the hydrophobicity and cationicity of the peptides and to increase bacterial cell selectivity. Among them, 9Pbw2 has high antibacterial activity without cytotoxicity. The results obtained in previous study suggest that the bactericidal action of 9Pbw2 may be attributed to the inhibition of the functions of intracellular components after penetration of the bacterial cell membrane. In order to understand structure-activity relationships, we determined the three-dimensional structure of 9Pbw2 in 200 mM DPC micelle by NMR spectroscopy. 9Pbw2 has one hydrophobic turn helix from $Trp^3$ to $Arg^8$ and positively charged residues at the N- and C-terminus. This result suggested that positively charged residues from position at the C-terminus in 9Pbw2 may be important for the primary binding to the negatively charged phospholipid head groups in bacterial cell membranes and hydrophobic residues in the middle portion face toward the acyl chains of the hydrophobic lipid in the bacterial cell membrane.

• 식물병연구
• /
• 제20권3호
• /
• pp.182-188
• /
• 2014

Because bacterial isolates from only a few genera have been developed commercially as biopesticides, discovery and characterization of novel bacterial strains will be a key to market expansion. Our previous screen using plant bioassays identified 24 novel biocontrol isolates representing 12 different genera. In this study, we characterized the 3 isolates showing the best biocontrol activities. The isolates were Pantoea dispersa WCU35, Proteus myxofaciens WCU244, and Exiguobacterium acetylicum WCU292 based on 16S rRNA sequence analysis. The isolates showed differential production of extracellular enzymes, antimicrobial activity against various fungal or bacterial plant pathogens, and induced systemic resistance activity against tomato gray mold disease caused by Botrytis cinerea. E. acetylicum WCU292 lacked strong in vitro antimicrobial activity against plant pathogens, but induced systemic resistance against tomato gray mold disease. These results confirm that the trait of biological control is found in a wide variety of bacterial genera.

• 한국치위생학회지
• /
• 제14권1호
• /
• pp.117-122
• /
• 2014

Objectives : The purpose of the study is to investigate the activities of Nelumbo nucifera leaf extracts on Streptococcus mutans, Streptococcus mitis, Streptococcus sobrinus, Porphyromonas gingivalis, Prevotella intermedia, and Treponema denticola. Methods : The inhibitory effect of lotus leaf extracts on the growth of oral bacteria was assessed in experiments with extracts from freshly harvested and pulverized lotus leaves and bacterial cultures of dental caries. Results : The results showed that N. nucifera extracts possess antimicrobial activity on all bacterial strains. The minimal inhibitory concentration (MIC) values varied from 4 mg/ml to 10 mg/ml against antimicrobial activity. The relative growth ratio (RGR) against of N. nucifera extracts were determined as 50% in concentration of 4.0 mg/ml. The extract of N. nucifera was effective in reducing on the glucosyltransferase (GTase) activity of six strains in vitro. Conclusions : Methanol extracts of lotus leaves showed antimicrobial effects on three bacterial species causing dental caries and three bacterial species causing periodontitis, as well as inhibitory effects on GTase activity.

• The Plant Pathology Journal
• /
• 제32권4호
• /
• pp.363-370
• /
• 2016

Pseudomonas syringae pv. actinidiae (Psa) causes bacterial canker disease in kiwifruit. Antibacterial activity of plant essential oils (PEOs) originating from 49 plant species were tested against Psa by a vapor diffusion and a liquid culture assays. The five PEOs from Pimenta racemosa, P. dioica, Melaleuca linariifolia, M. cajuputii, and Cinnamomum cassia efficiently inhibited Psa growth by either assays. Among their major components, estragole, eugenol, and methyl eugenol showed significant antibacterial activity by only the liquid culture assay, while cinnamaldehyde exhibited antibacterial activity by both assays. The minimum inhibitory concentrations (MICs) of estragole and cinnamaldehyde by the liquid culture assay were 1,250 and 2,500 ppm, respectively. The MIC of cinnamaldehyde by the vapor diffusion assay was 5,000 ppm. Based on the formation of clear zones or the decrease of optical density caused by these compounds, they might kill the bacterial cells and this feature might be useful for managing the bacterial canker disease in kiwifruit.

• 대한의생명과학회지
• /
• 제26권4호
• /
• pp.383-388
• /
• 2020

Ingestion of food contaminated with microorganism, if not always, could lead to severe health problem. Preservatives has been added to food to prevent food from being contaminated with microorganism. But, these have potential to threaten the health. Therefore, much effort has been taken to find the safe materials showing the anti-microbial activity. In this study, we investigated the anti-bacterial activity of Oenothera lamarckiana aerial part extract against eight bacteria strain. In paper disc assay, extract inhibited the growth of Staphylococcus aureus, Methicillin-resistant S. aureus, Bacillus cereus and Shigella dysenteriae at 200 μg/disc, but not against Escherichia coli, E. coli O157:H7, Salmonella Typhi and S. enteritidis. Minimum inhibitory concentration (MIC) against Staphylococcus aureus, Methicillin-resistant S. aureus, Bacillus cereus and Shigella dysenteriae is 250, 250, 500 and 500 μg/mL, respectively. Compared with reported MIC of other plant resources, O. lamarckiana aerial part extract showed the relatively high anti-bacterial activity. O. lamarckiana aerial part could be suitable for the preservative development. But, it still remains to be studied to evaluate safety and so on.

• The Korean Journal of Physiology and Pharmacology
• /
• 제26권4호
• /
• pp.229-238
• /
• 2022

Severe bacterial infections are frequently accompanied by depressed neutrophil functions. Thus, agents that increase the microbicidal activity of neutrophils could add to a direct antimicrobial therapy. Lysophosphatidylcholine augments neutrophil bactericidal activity via the glycine (Gly)/glycine receptor (GlyR) α2/TRPM2/p38 mitogen-activated protein kinase (MAPK) pathway. However, the direct effect of glycine on neutrophil bactericidal activity was not reported. In this study, the effect of glycine on neutrophil bactericidal activity was examined. Glycine augmented bactericidal activity of human neutrophils (EC₅₀ = 238 μM) in a strychnine (a GlyR antagonist)-sensitive manner. Glycine augmented bacterial clearance in mice, which was also blocked by strychnine (0.4 mg/kg, s.c.). Glycine enhanced NADPH oxidase-mediated reactive oxygen species (ROS) production and TRPM2-mediated [Ca²⁺]_i increase in neutrophils that had taken up E. coli. Glycine augmented Lucifer yellow uptake (fluid-phase pinocytosis) and azurophil granule-phagosome fusion in neutrophils that had taken up E. coli in an SB203580 (a p38 MAPK inhibitor)-sensitive manner. These findings indicate that glycine augments neutrophil microbicidal activity by enhancing azurophil granule-phagosome fusion via the GlyRα2/ROS/calcium/p38 MAPK pathway. We suggest that glycine could be a useful agent for increasing neutrophil bacterial clearance.

• 한국식품위생안전성학회지
• /
• 제31권5호
• /
• pp.380-385
• /
• 2016

사람과 어류에게 감염증을 유발하는 Edwardsiella sp., Streptococcus sp. 및 Vibrio sp. 의 해양 유해세균에 대한 해조류 추출물의 항균 활성을 조사하였다. 연구에 사용된 4종의 식용 해조류 중에서 감태 MeOH 추출물이 본 연구에서 사용 된 6종의 모든 해양 유해세균에 대해 넓은 범위의 항균 활성을 나타내었다. 감태의 MeOH 추출물의 유기용매 분획 추출물들 중에서, EtOAc 분획 추출물이 가장 높은 항균활성을 나타내었으며 6종의 해양 유해세균에 대하여 $128{\mu}g/mL$에서 $256{\mu}g/mL$의 MIC 값을 나타내었다. 또한, HPLC 분석에 의해 감태 EtOAc 분획 추출물에 phlorotannin 화합물인 dieckol이 다량 존재하고 있는 것이 확인 되었다. 결론적으로, 감태 추출물의 phlorotannin 화합물이 여러 유해세균에 대한 강한 항균활성을 나타내는 것처럼, 해양 유해세균에 대해서도 강한 항균활성을 나타내는 것으로 판단된다.

• 한국수산과학회지
• /
• 제47권1호
• /
• pp.45-51
• /
• 2014

Scuticociliates are regarded as serious pathogens in marine aquaculture worldwide. In Korea, they cause mass-mortalities in fish such as the commercially important olive flounder Paralichthys olivaceus. In particular, mixed infections of scuticociliates with pathogenic bacteria have been commonly reported. During efforts to identify natural marine-algae derived products that possess anti-bacterial and anti-scuticociliate properties, we found that an 80% methanolic extract of the red alga Polysiphonia morrowii Harvey exhibits both anti-scuticociliate activity against Miamiensis avidus, which is a major causative agent of scuticociliatosis, and anti-bacterial activities against fish pathogenic bacteria. Activity-guided fractionation and isolation of the 80% methanolic extract of P. morrowii yielded three bromophenols, which were identified as 3-bromo-4,5-dihydroxybenzyl methyl ether (1), 3-bromo-4,5-dihydroxybenzaldehyde (2) and urceolatol (3) based on spectroscopic analyses. 3-bromo-4,5-dihydroxybenzyl methyl ether (1) showed the highest anti-bacterial and anti-scuticociliate activities, with a minimal inhibitory concentration (MIC) of $62.5{\mu}g/mL$ (against Vibrio anguillarum) and minimal lethal concentration (MLC) of 62.5 ppm (in seawater). Investigations of the anti-bacterial and anti-scuticociliate activities of seventeen bromophenol derivatives, including the three isolated natural bromophenols, showed that the existence of an electron donating group or atom with a non-covalent electron pair at $C_4$ of the 2-bromophenol structure may be important in anti-scuticociliate activity. These findings suggest that the extract and bromophenol derivatives of P. morrowii may provide useful alternatives in aquaculture anti-scuticociliate therapies.

• The Plant Pathology Journal
• /
• 제17권5호
• /
• pp.249-256
• /
• 2001

Xanthomonas axonopodis pv. glycines 8ra produces a bacteriocin called glycinecinA, which specifically inhibits the growth of bacteria belonging to Xanthomonas species. GlycinecinA was produced by culturing Escherichia coli DH5 containing biosynthetic genes for glycinecinA, and was tested for its control effect against X. vesicatoria on red pepper and X. oryzae pv. oryzae on rice. The bacteriocin activity was much higher in the cell extract than in the supernatant. It reached a maximum level at the stationary phase, ws maintained up to 2 months at room temperature and approximately 10 months at $4^{\circ}$. The optimum concentration of glycinecinA for the control in the greenhouse and in the field was 12,800 AU/ml. In this study, the activity of glycinecinA on rice and red pepper leaves continued for 7-8 days, during which the pathogen populations remained at low levels. Bacterial leaf spot of red pepper and bacterial leaf blight of rice were significantly reduced by the bacteriocin treatments. The control efficacy was as high as, or even higher than, the chemical treatment of copper hydroxide. These results suggest that the bacteriocin is a potential control agent for bacterial diseases.