• Korean Journal of Veterinary Research
• /
• v.62 no.1
• /
• pp.5.1-5.5
• /
• 2022

Many countries have imposed regulations relating to concerns that hide contamination will affect the cleanliness of abattoirs. However, South Korea has not indicated any clear criteria. The purpose of this study is to use surrogate bacteria to measure the contamination in abattoirs caused by contaminated cattle hides. The swab contact method and plate count method are used. Surrogate bacteria are found in most internal environments after the final process. These surrogates remained on the carcass even after the final washing process. This paper is the first study in South Korea that use surrogate bacteria to analyze contamination levels in abattoirs.

• Journal of Applied Biological Chemistry
• /
• v.66
• /
• pp.345-352
• /
• 2023

Antibacterial activity against foodborne bacteria (Bacillus cereus, Staphylococcus aureus, Salmonella Enteritidis) and inhibitory activity against murine norovirus, a human norovirus surrogate, of 28 extracts from plants endemic to Korea were investigated in this study. All plant extracts showed antibacterial activity only against gram-positive bacteria, B. cereus and S. aureus. Extracts from Callistemon speciosus and Nymphaea tetragona showed inhibition zones of 16.54 and 24.35 mm against B. cereus and S. aureus, respectively, presenting the highest antibacterial activities recorded in this study. Among all samples, Ardisia japonica extract at concentrations of 100 and 200 ㎍/mL showed the highest virucidal activities of 96.6 and 100.0%, respectively. Ardisia japonica, Duchesnea indica, Polygonum aviculare, and Geum japonicum extracts showed high antibacterial and virucidal activity simultaneously without Raw 264.7 cell cytotoxicity. These plant extracts may serve as potential antimicrobials to control foodborne infections.

• Food Science of Animal Resources
• /
• v.33 no.4
• /
• pp.522-530
• /
• 2013

The ability of probiotics to adhere to the intestinal epithelium likely plays an important role in their colonization of the gastrointestinal tract. Here, we performed high-throughput screening (HTS) for suitable characteristics of potential probiotic bacteria using attachment and colonization ability through a C. elegans surrogate in vivo model. A total of 100 strains of lactic acid bacteria (LAB) isolated from infant feces were subjected to the colonization assay using C. elegans intestine. Based on colonization ability, we showed that nine isolates have a high attachment ability during whole experimental periods (up to 168 h), compared to Lactobacillus rhamnosus strain GG as a control. Also, through the use of an in vitro cell attachment model, nine isolates revealed highly binding activity to the mucus layer. Next, the selected 9 isolates were assayed for their survival ability when exposed to acidic and bile conditions as well as cholesterol reduction and the utilization of prebiotic substrates. As a result, the isolated nine strains were determined to be highly resistant to acid and bile conditions. In addition, they have significant activity for the reduction of cholesterol and utilization of several prebiotic substrates as a carbon source. Finally, the selected nine strains were identified by either L. rhamnosus or L. plantarum (4 strains for L. rhamnosus and 5 strains for L. plantarum, respectively). Taken together, we propose that the direct colonization of probiotics using C. elegans may be applicable to the rapid screening of valuable probiotic strains in vivo.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.7
• /
• pp.1015-1025
• /
• 2015

The development of diverse polymyxin derivatives is needed to solve the toxicity and resistance problems of polymyxins. However, no platform has generated polymyxin derivatives by genetically engineering a polymyxin synthetase, which is a nonribosomal peptide synthetase. In this study, we present a two-step approach for the construction of engineered polymyxin synthetases by substituting the adenylation (A) domains of polymyxin A synthetase, which is encoded by the pmxABCDE gene cluster of Paenibacillus polymyxa E681. First, the seventh L-threonine-specific A-domain region in pmxA was substituted with the L-leucine-specific A-domain region obtained from P. polymyxa ATCC21830 to make polymyxin E synthetase, and then the sixth D-leucine-specific A-domain region (A_6-D-Leu-domain) was substituted with the D-phenylalanine-specific A-domain region (A_6-D-Phe-domain) obtained from P. polymyxa F4 to make polymyxin B synthetase. This step was performed in Escherichia coli on a pmxA-containing fosmid, using the lambda Red recombination system and the sacB gene as a counter-selectable marker. Next, the modified pmxA gene was fused to pmxBCDE on the chromosome of Bacillus subtilis BSK4dA, and the resulting recombinant strains BSK4-PB and BSK4-PE were confirmed to produce polymyxins B and E, respectively. We also succeeded in constructing the B. subtilis BSK4-PP strain, which produces polymyxin P, by singly substituting the A_6-D-Leu-domain with the A_6-D-Phe-domain. This is the first report in which polymyxin derivatives were generated by genetically engineering polymyxin synthetases. The two recombinant B. subtilis strains will be useful for improving the commercial production of polymyxins B and E, and they will facilitate the generation of novel polymyxin derivatives.

• Korean Journal of Microbiology
• /
• v.55 no.2
• /
• pp.177-179
• /
• 2019

Pseudomonas kribbensis CHA-19 was isolated from a temperate forest soil (mid latitude) in New Jersey, USA, for its ability to degrade humic acids, a main component of humic substances (HS), and subsequently confirmed to be able to decolorize lignin (a surrogate for HS) and catabolize lignin-derived ferulic and vanillic acids. The draft genome sequence of CHA-19 was analyzed to discover the putative genes for depolymerization of polymeric HS (e.g., dye-decolorizing peroxidases and laccase-like multicopper oxidases) and catabolic degradation of HS-derived small aromatics (e.g., vanillate O-demethylase and biphenyl 2,3-dioxygenase). The genes for degradative activity were used to propose a HS degradation pathway of soil bacteria.

• Food Science of Animal Resources
• /
• v.35 no.1
• /
• pp.91-100
• /
• 2015

The present study was conducted to screen candidate probiotic strains for anti-inflammatory activity. Initially, a nitric oxide (NO) assay was used to test selected candidate probiotic strains for anti-inflammatory activity in cultures of the murine macrophage cell line, RAW 264.7. Then, the in vitro probiotic properties of the strains, including bile tolerance, acid resistance, and growth in skim milk media, were investigated. We also performed an in vitro hydrophobicity test and an intestinal adhesion assay using Caenorhabditis elegans as a surrogate in vivo model. From our screening, we obtained 4 probiotic candidate lactic acid bacteria (LAB) strains based on their anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW 264.7 cell cultures and the results of the in vitro and in vivo probiotic property assessments. Molecular characterization using 16S rDNA sequencing analysis identified the 4 LAB strains as Lactobacillus plantarum. The selected L. plantarum strains (CAU1054, CAU1055, CAU1064, and CAU1106) were found to possess desirable in vitro and in vivo probiotic properties, and these strains are good candidates for further investigations in animal models and human clinical studies to elucidate the mechanisms underlying their anti-inflammatory activities.

• The Journal of the Korean dental association
• /
• v.51 no.9
• /
• pp.501-510
• /
• 2013

This paper reviews a current view regarding the association between periodontitis and atherosclerotic cardiovascular diseases (ACVD). Many evidences have suggested that there exist biological mechanisms by which periodontitis can lead to ACVD. Periodontal infection can lead to direct bacterial invasion into endothelial tissues through the blood stream, then the bacteria can activate the host inflammatory response followed by atheroma formation, maturation and exacerbation. Also, chronic periodontal infections may indirectly induce endothelial activation or dysfunction through a state of systemic inflammation as evidenced by elevated plasma acute proteins, IL-6 and fibrinogen as well. There is moderate evidence that periodontal treatment can reduce systemic inflammation and improvement of both clinical surrogate markers. But there is no periodontal intervention study available on primary ACVD prevention. There is consistent and strong epidemiologic evidence, including in vitro, animal and clinical studies, that periodontitis imparts increased risk for future ACVD. However, evidences from intervention trials to date are not sufficient to confirm the multi directional causality of periodontitis in ACVD etiology. Well-designed intervention trials on the impact of periodontal treatment on the prevention of ACVD outcomes are needed.

• Journal of Korean Society on Water Environment
• /
• v.21 no.5
• /
• pp.470-476
• /
• 2005

The Korean Water Quality Index (K-WQI) was applied to the rivers located in the watershed of Daecheong Lake to assess the status of river water quality, and propose potential target constituents for better water quality management in the watershed. The estimated K-WQI value for each river was varied from 70 to 90, and Youngdongcheon showed the worst score while Mujunamdeachen showed the best score. The total nitrogen (TN) and total coliform bacteria were identified as the most significant constituents that degrade the K-WQI values in the rivers. The correlation coefficients (r) were determined between K-WQI and the delivered specific load ($kg/km^2/yr$) of BOD, TN, and TP to justify potential target constituents that have a great influence on the improvement of K-WQI values. The results showed that TN (r=-0.86) and TP (r=-0.85) have a strong negative relationships with K-WQI, but BOD have almost no effect. This implies that BOD, the surrogate parameter for organic pollutants, is no more a feasible water quality variable for the water quality management in the study site.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.27 no.5
• /
• pp.642-648
• /
• 2024

If a nation or a terrorist organization produced biological agents, they are likely stored in a form of liquid concentrate. In the present study, four chemical reagents, hydrogen peroxide, sodium dichloroisocyanurate (NaDCC), Perasafe, and DF200, were investigated on their potentials as safe, efficient and eco-friendly decontaminants for biological agents. Escherichia coli, α-amylase, and bacteriophage T4 were used as surrogate strains for biological agents. Hydrogen peroxide and DF200 showed drawbacks of a rapid heat evolution upon neutralization and thick foam building up, respectively. Perasafe was effective against E. coli and T4, but it did not inactivate α-amylase while the others were able to inactivate all three types of the surrogates. NaDCC was the most suitable decontaminant for its effectiveness against all three types of surrogates at low concentrations and being able to be neutralized without aforementioned problems.

• Journal of Microbiology and Biotechnology
• /
• v.34 no.5
• /
• pp.1109-1118
• /
• 2024

Probiotics, specifically Lacticaseibacillus rhamnosus, have garnered attention for their potential health benefits. This study focuses on evaluating the probiotic properties of candidate probiotics L. rhamnosus IDCC 3201 (3201) using the Caenorhabditis elegans surrogate animal model, a well-established in vivo system for studying host-bacteria interactions. The adhesive ability to the host's gastrointestinal tract is a crucial criterion for selecting potential probiotic bacteria. Our findings demonstrated that 3201 exhibits significantly higher adhesive capabilities compared with Escherichia coli OP50 (OP50), a standard laboratory food source for C. elegans and is comparable with the widely recognized probiotic L. rhamnosus GG (LGG). In lifespan assay, 3201 significantly increased the longevity of C. elegans compared with OP50. In addition, preconditioning with 3201 enhanced C. elegans immune response against four different foodborne pathogenic bacteria. To uncover the molecular basis of these effects, transcriptome analysis elucidated that 3201 modulates specific gene expression related to the innate immune response in C. elegans. C-type lectin-related genes and lysozyme-related genes, crucial components of the immune system, showed significant upregulation after feeding 3201 compared with OP50. These results suggested that preconditioning with 3201 may enhance the immune response against pathogens. Metabolome analysis revealed increased levels of fumaric acid and succinic acid, metabolites of the citric acid cycle, in C. elegans fed with 3201 compared with OP50. Furthermore, there was an increase in the levels of lactic acid, a well-known antimicrobial compound. This rise in lactic acid levels may have contributed to the robust defense mechanisms against pathogens. In conclusion, this study demonstrated the probiotic properties of the candidate probiotic L. rhamnosus IDCC 3201 by using multi-omics analysis.