• Korean Journal of Veterinary Research
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• v.51 no.4
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• pp.281-288
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• 2011

Lactobacillus salivarius JWS 58 (JWS 58) and Lactobacillus plantarum JWS 1354 (JWS 1354) are isolated from duck intestine and have ability to produce bacteriocin. The objective of this study was to evaluate the immunomodulatory effects of JWS 58 and JWS 1354. The nitric oxide (NO) and cytokines (IL-$1{\beta}$ and TNF-${\alpha}$) were measured in C57BL/6 mouse peritoneal macrophages to determine immune enhancing effects of JWS 58 and JWS 1354. A Listeria (L.) monocytogenes challenge mice model was used to evaluate immune enhancement ability of JWS 58 and JWS 1354 in vivo. The results showed that JWS 58 and JWS 1354 increased the production of NO or cytokines by peritoneal macrophages and that oral administration of viable probiotic strains in mice elicited the immuno-modulatory effect upon L. monocytogenes challenge. JWS 1354 showed stronger immune enhancing effects than JWS 58. Collectively, this study demonstrated that Lactobacillus strain JWS 58 and JWS 1354 possess immune enhancing effect. Furthermore, two stains are expected to use feed supplement to prevent diseases by pathogenic bacteria through releasing bacteriocin and enhancing host immune responses in animal.

• Genomics & Informatics
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• v.14 no.4
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• pp.255-264
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• 2016

The plethora of genome sequence information of bacteria in recent times has ushered in many novel strategies for antibacterial drug discovery and facilitated medical science to take up the challenge of the increasing resistance of pathogenic bacteria to current antibiotics. In this study, we adopted subtractive genomics approach to analyze the whole genome sequence of the Fusobacterium nucleatum, a human oral pathogen having association with colorectal cancer. Our study divulged 1,499 proteins of F. nucleatum, which have no homolog's in human genome. These proteins were subjected to screening further by using the Database of Essential Genes (DEG) that resulted in the identification of 32 vitally important proteins for the bacterium. Subsequent analysis of the identified pivotal proteins, using the Kyoto Encyclopedia of Genes and Genomes (KEGG) Automated Annotation Server (KAAS) resulted in sorting 3 key enzymes of F. nucleatum that may be good candidates as potential drug targets, since they are unique for the bacterium and absent in humans. In addition, we have demonstrated the three dimensional structure of these three proteins. Finally, determination of ligand binding sites of the 2 key proteins as well as screening for functional inhibitors that best fitted with the ligands sites were conducted to discover effective novel therapeutic compounds against F. nucleatum.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.401-410
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• 2006

Dental caries results from localized demineralization of tooth enamel by acids of bacterial origin produced from the fermentation of dietary sugars. A group of related oral bacteria, collectively known as mutans streptococci, are implicated as the primary etiological agents of human caries. Within this group, Streptococcus mutans has been known as a causative agent for dental caries. As well as acid production yielding the demineralization of tooth enamel, adherence and colonization of S. mutans to the teeth are also important for their virulence Cell-surface fibrillar proteins, which mediate adherence to the salivary pellicle are virulence components of mutans streptococci, and primary candidates for a human caries vaccine. Here we report that the AgI/II gene from S. mutans GS-5 were cloned by PCR amplification of the bacterial chromosomal DNA and the integrity of cloned genes were confirmed by nucleotide sequencing. Sequence analyses showed the sequence alignment of 280 nucleotides between the cloned AgI/II and the reported sequence of S. mutans GS-5 showed the perfect match The cloned genes which signal nucleotide was truncated, were transferred into bacterial expression vector and the recombinant proteins were purified as His-tag fusion proteins In order to generate polyclonal antibodies against the recombinant proteins, AgI/II mr, some $100{\mu}g$ of the proteins was injected into mice three times. It can be used for an effective vaccine production to prevent dental caries caused by pathogenic S. mutans.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.334-340
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• 2010

It is well known that smoking as well as drinking is a factor of stomatopathy, however there are few investigations about comparison of oral flora between smokers and non-smokers. In this study, we isolated the oral flora of 30 smokers and 30 non-smokers and cultured them on blood agar plates. The isolated pathogenic microorganisms were tested for antibiotic susceptibility and resistance using the Kirby-Bauer antibiotic testing method. Each colony was stained using the Gram staining method and was identified by an automatic identifier, known as the VITEK system. We isolated 41 colonies from smokers' oral cavity, and they were sorted as 63% of Gram-positive cocci, 29% of Gram-negative cocci, 3% of Gram-positive bacilli, and 5% of Gram-negative bacilli by gram staining, whereas 38 colonies were isolated from non-smoters' oral cavity, and their proportions were 55% of Gram-positive cocci, 26% of Gram-negative cocci, 3% of Gram-positive bacilli, and 16% of Gram-negative bacilli. The VITEK system revealed specific distribution of bacteria species that Streptococcus mutans (6/41), Gemella morillorum (6/41), Streptococcus oralis (2/41), Streptococcus pneumoniae (1/41), Staphylococcus aureus (3/41), Streptococcus anginosus (1/41), Streptococcus intermedius (1/41), Streptococcus uberis (1/41), and Streptococcus sanguinis (1/41) in smokers oral cavity whereas Streptococcus sanguinis (8/38), Staphylococcus aureus (1/38), Staphylococcus auricularis (1/38), Streptococcus uberis (1/38), Streptococcus intermedius (1/38), Streptococcus mutans (1/38), and Streptococcus oralis (1/38) in those of non-smokers'. Three cases of Staphylococcus aureus from smokers produced Beta-lactamase and were identified methicillin-resistance Staphylococcus aureus (MRSA). However one case of Staphylococcus aureus from non-smoker did not produce Beta-lactamase and was sensitive to methicillin. In conclusion, the distribution of oral flora was different between smokers' and non-smokers' oral cavity, especially Gemella morillorum and MRSA were predominantly found in smoker's oral cavity. These results are useful in the treatment and prevention of patients with stomatopathy caused by smoking.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.76-92
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• 1997

Porpilyromonas endodontalis is specifically involved in endodontic infections. The bacterium can be isolated almost exclusively only from infected rool canals. P. gingivalis also has been implicated in endodontic infection. Pathogemcity of P. gingival is is attributed to a variety of virulence factors, especially proteases, produced by the bacterium. Importance of P. endodontalis in endodontic infection has been revealed. However, the pathogenic property of P. endodontalis has not been extensively studied. The present study was undertaken to characterize the proteolytic activity of P. endodontalis and compare the activity with that of P. gingivalis which has the most potent and diverse proteases among oral bacteria. For this purpose, culture supematants(SUP) and cell extracts(CE) were obtained from these two bacteria and were subjected to zymography using 15% polyacrylamide gel copolymerized with gelatin, type I, IV collagens or albumin. Hydrolysis of the collagens was further investigated by the cleavage assay using native type I and IV collagens in solution-phase. The results were as follows: 1. P. endodontalis apparently has a proteolytic activity that is comparable with that of P. gingivalis. 2. SUP and CE obtained from P. endodontalis and P. gingival is showed the strongest activity for gelatin, followed by type I and IV collagens, and albumin. 3. In the zymography, no noticeable difference in proteolytic activity for gelatin and albumin between the SUP and CE was observed, but in the cleavage assay using native collagens, the SUP showed a stronger collagenolytic activity than the CE. 4. The gelatinolytic activity of both the SUP and CE from these two bacteria was diminished in the presence of $CaCl_2$ or reducing agents such as ${\beta}$-mercaptoethanol and dithiothreitol(DTT). 5. Type I(calf skin and human placenta) collagenolytic activity of P. endodontalis and P. gingivalis was reduced by DTT but not affected by $CaCl_2$. The inhibitory effect of DTT, however, was reduced to some extent by $CaCl_2$. 6. Type IV collagenolytic activity of these two bacteria was not affected by $CaCl_2$ but increased to some extent in association with the reducing agents. 7. Hydrolysis of albumin by P. endodontalis and P. gingivalis was demonstrated only in the presence of the reducing agents. The overall results indicate that with respect to proteolytic activity, P. endodontalis appears to be as potent as P. gingivalis, or maybe more, and its proteolytic characteristic is similar to that of P. gingivalis. This suggests that P. endodontalis has so potent proteolytic activity that can participate by itself in endodontic infections and apical periodontitis, causing tissue destruction.

• Korean Journal of Veterinary Research
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• v.42 no.1
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• pp.45-54
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• 2002

The study was carried out to characterize the pharmacokinetics after intravenous (iv, 20 mg/kg) and oral (p.o. 100 mg/kg) administration as oxytetracycline (OTC) and tiamulin (TIA) mixture in swine and to determine interaction between OTC and TIA against various pig pathogenic bacteria. The antibacterial effects of OTC in combination with TIA in vitro showed synergistic effect against Salmonella typhimurium 1925, Pasteurella multocida Type A, P. multocida Type D, Krebsiella Pneumoniae 2001, K. Pneumoniae 1560, K. Pneumoniae 2208, Haemophillus pleuropneumonia S 2, and H. pleuropneumonia S 5, but against additive effect E. coli K88ab and S. choleraesuis on the basis of fractional inhibitory concentration (FIC) index. On the while, after i.v. and p.o. administration of OTC and TIA mixture, each OTC and TIA concentrations in plasma were fitted to an open two-compartment model. After i.v. administration of OTC-TIA mixture, the mean distribution half-life ($T_{1/2{\alpha}}$) of OTC and TIA in plasma showed 0.29 h and 0.17 h, and the mean elimination half-life ($T_{1/2{\beta}}$) of those was 4.36 h and 6.64 h, respectively. The mean volume of distribution at steady state ($Vd_{ss}$) of OTC and TIA was $0.85{\ell}/kg$ and $2.44{\ell}/kg$, respectively. After oral administration of OTC and TIA mixture, the mean maximal absorption concentrations ($C_{max}$) of OTC and TIA were $0.60{\mu}g/m{\ell}$ at 1.07 h ($T_{max}$) and $1.68{\mu}g/m{\ell}$ at 1.85 h ($T_{max}$), respectively. The mean elimination half-life ($T_{1/2{\beta}}$) of those showed 6.84 h and 6.36 h. In conclusion, we could suggest in this study that the combination of OTC and TIA may be recommended for the antibacterial therapy against polymicrobial infections, and both OTC and TIA showed large distribution to tissues and high $C_{max}$ after p.o. administration.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.3
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• pp.307-314
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• 2016

Cheese is generally considered a safe and nutritious food, but foodborne illnesses linked to cheese consumption have occurred in many countries. Several microbial risk assessments related to Listeria monocytogenes, Staphylococcus aureus, and Escherichia coli infections, causing cheese-related foodborne illnesses, have been conducted. Although the assessments of microbial risk in soft and low moisture cheeses such as semi-hard and hard cheeses have been accomplished, it has been more focused on the correlations between pathogenic bacteria and soft cheese, because cheese-associated foodborne illnesses have been attributed to the consumption of soft cheeses. As a part of this microbial risk assessment, predictive models have been developed to describe the relationship between several factors (pH, Aw, starter culture, and time) and the fates of foodborne pathogens in cheese. Predictions from these studies have been used for microbial risk assessment as a part of exposure assessment. These microbial risk assessments have identified that risk increased in cheese with high moisture content, especially for raw milk cheese, but the risk can be reduced by preharvest and postharvest preventions. For accurate quantitative microbial risk assessment, more data including interventions such as curd cooking conditions (temperature and time) and ripening period should be available for predictive models developed with cheese, cheese consumption amounts and cheese intake frequency data as well as more dose-response models.

• Journal of Oral Medicine and Pain
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• v.32 no.2
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• pp.137-150
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• 2007

Trees emit phytoncide into atmosphere to protect them from predation. Phytoncide from different trees has its own unique fragrance that is referred to as forest bath. Phytoncide, which is essential oil of trees, has microbicidal, insecticidal, acaricidal, and deodorizing effect. The present study was performed to examine the effect of phytoncide on Porphyromonas gingivalis, which is one of the most important causative agents of periodontitis and halitosis. P. gingivalis 2561 was incubated with or without phytoncide extracted from Hinoki (Chamaecyparis obtusa Sieb. et Zucc.; Japanese cypress) and then changes were observed in its cell viability, antibiotic sensitivity, morphology, and biochemical/molecular biological pattern. The results were as follows: 1. The phytoncide appeared to have a strong antibacterial effect on P. gingivalis. MIC of phytoncide for the bacterium was determined to be 0.008%. The antibacterial effect was attributed to bactericidal activity against P. gingivalis. It almost completely suppressed the bacterial cell viability (>99.9%) at the concentration of 0.01%, which is the MBC for the bacterium. 2. The phytoncide failed to enhance the bacterial susceptibility to ampicillin, cefotaxime, penicillin, and tetracycline but did increase the susceptibility to amoxicillin. 3. Numbers of electron dense granules, ghost cell, and vesicles increased with increasing concentration of the phytoncide, 4. RT-PCR analysis revealed that expression of superoxide dismutase was increased in the bacterium incubated with the phytoncide. 5. No distinct difference in protein profile between the bacterium incubated with or without the phytoncide was observed as determined by SDS-PAGE and immunoblot. Overall results suggest that the phytoncide is a strong antibacterial agent that has a bactericidal action against P. gingivalis. The phytoncide does not seem to affect much the profile of the major outer membrane proteins but interferes with antioxidant activity of the bacterium. Along with this, yet unknown mechanism may cause changes in cell morphology and eventually cell death.

• Journal of Animal Science and Technology
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• v.48 no.6
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• pp.907-920
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• 2006

This study was conducted to investigate the inhibitory activity of Lactobacillus spp., Bacillus ssp., and calf fecal isolates against pathogenic Salmonella typhimurium, E. coli, Listeria monocytogenes, and Staphylococcus aureus. Among thirteen strains of Lactobacillus ssp. tested, Lactobacillus helveticus CU631 showed the highest inhibition against three pathogens, whereas Bacillus spp. showed a weak inhibitory activity. Four calf fecal isolates were identified as Lactobacillus pentosus CU13, CU05, Pediococcus pentosaceus CUR02, and Lactobacillus lactis ssp. lactis CUM14. The whole cell and cell wall components of L. rhamnosus CU02 and L. pentosus CU13 were active in the inhibition of L. monocytogenes. The medium components and levels, which affect on the inhibitory activity, were revealed as Tween 80 1.0%, peptone 3.0%, yeast extract 3.0%, glucose 3.0%, beef extract 3.0%, and NaCl 1.0～3.0%, respectively. Inhibitory activity of the supernatant culture medium was not affected by catalase and proteinase K treatment but affected by heat treatment at 80℃ and netralization, which implies that the inhibitory activity is due to the production of organic acids during the growth. L. pentosus CU13 and L. rhamnosus CU02 exhibited broad inhibition spectrum against 16 out of 21 strains including some pathogens. Oral administration of L. rhamnosus CU02 to the mice infected with E. coli O157:H7 was proven to be effective to recover their body weight during the experimental period.

• Korean journal of applied entomology
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• v.51 no.1
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• pp.39-45
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• 2012

The entomopathogenic bacterium, $Xenorhabdus$ sp., was isolated from an entomopathogenic nematode, $Steinernema$ $monticolum$. When these bacteria were injected into the hemocoel of the diamondback moth, $Plutella$ $xylostella$, they caused significant mortality. However, the bacterium was not pathogenic when it was administered orally. This study showed that $Xenorhabdus$ sp. significantly enhanced oral pathogenicity of $Bacillus$ $thuringiensis$ (Bt) against the last instar larvae of $P.$ $xylostella$. Different ratios of culture broth of $Xenorhabdus$ sp. and Bt showed significantly different pathogenicities against $P.$ $xylostella$. In field tests, the optimal bacterial mixture significantly enhanced control efficacy against $P.$ $xylostella$ compared to Bt treatment alone. These results demonstrated that $Xenorhabdus$ sp. culture broth can be developed as a potent biopesticide by enhancing the insecticidal efficacy of Bt.