• 한국수산과학회지
• /
• 제55권5호
• /
• pp.505-513
• /
• 2022

In this study, 143 strains of Enterococcus spp. were isolated from inland pollution sources near shellfish farms on the west coast of South Korea. Not all isolated Enterococcus spp. strains possessed vancomycin resistance genes (VanA and VanB). However, since vancomycin-resistance Enterococcus (VRE) have been detected not only in the clinical field but also out in the world, it is possible that the VRE gene may be transferred to other bacterial strains commonly found in coastal waters where seafood is produced. It is important to monitor trends in the appearance of VRE. In addition, antimicrobial resistance patterns of isolates were examined in this study. Overall antimicrobial resistance rates were high: ciprofloxacin (32.2% of isolates resistant), chloramphenicol (30.8%), quinupristin/dalfopristin (19.6%), and tylosin (15.4%). Eight E. faecium strains (6.2%), out of the 129 strains assessed, showed multidrug resistance. All multidrug-resistant E. faecium showed resistance to erythromycin, quinupristin/dalfopristin, tetracycline, and tylosin, in all 14 strains. All multidrug-resistant E. faecalis showed resistance to erythromycin, quinupristin/dalfopristin, tetracycline, and tylosin. Both multidrug-resistant E. faecium and multidrug-resistant E. faecalis showed common resistance to erythromycin, quinupristin/dalfopristin, tetracycline, and tylosin.

• 한국수산과학회지
• /
• 제55권5호
• /
• pp.495-504
• /
• 2022

This study examined the antimicrobials properties of bacteria using the minimum inhibitory concentration method. The bacteria were isolated from 30 shellfish (oysters and short neck clams) collected from Jawol-myeon, Ongjin-gun, Incheon and Iwon-myeon, Taean-gun, Chungcheongnam-do, on the west coast of Korea. A total of 528 bacteria were isolated from June to October 2020 and were classified into land-originating (LB; 264 strains) and marine-originating (MB; 264 strains) bacterial groups. Of the LB strains, 10 genera were identified, of which nine were Enterobacteriaceae. All MB strains were identified as species of the genus Vibrio spp.. Antimicrobial resistance to one or more agents was observed in 77.3% of the LB strains, and 90-100% of them were resistant to ampicillin Escherichia spp. were not resistant to ampicillin. The overall multidrug resistance rate of the LB strains was 49.2%, with 85 resistance patterns. Antimicrobial resistance to one or more agents was observed in 98.1% of the MB strains, because most of the V. alginolyticus and V. parahaemolyticus strains were resistant to ampicillin. The overall multidrug resistance rate of the MB strains was 1.9% with 19 resistance patterns.

• 융합정보논문지
• /
• 제11권5호
• /
• pp.223-231
• /
• 2021

유산균에 의한 감국 추출물(CIL)의 항산화능의 변화를 알아보기 위해 64%, 80% ethanol 로 추출한 농도별 CIL를 발효시켜 total phenolic contents (TPC), flavonoid, 2,2-diphenyl-1-picrylhydrazyl (DPPH), reducing power (RP), linoleic acid 자동산화 저해활성의 변화를 확인해 보았다. TPC의 경우 3109, 3237에서 증가하였으며, flavonoid에서는 모든 균주에서 감소를 나타냈다. DPPH 측정에서는 64% CIL 발효 후 3074, 3109에서 증가하였으며, 80% CIL 발효에서는 모든 균주가 증가를 나타냈다. RP측정에서는 64%, 80% CIL에서 모든 균주에서 증가를 보였으며, linoleic acid 자동산화 저해활성에서는 모든 균주에서 감소를 나타냈다. 특히 3109 항산화능을 평가하는 DPPH와 RP 측정에서 다른 균주에 비해 전반적으로 높게 측정이 되었다. 결과적으로 4종의 유산균 중에서 3109가 발효과정을 통해서 CIL의 항산화 효능을 효과적으로 증대하는 것을 확인할 수 있었다.

• Journal of Ginseng Research
• /
• 제47권1호
• /
• pp.159-165
• /
• 2023

Background: Red ginseng marc, the residue of red ginseng left after water extraction, is rich in dietary fiber. Dietary fiber derived from fruits or vegetables can promote the proliferation of probiotics, and it is a key technology in the food industry to increase the productivity of probiotics by adding growth-enhancing substances such as dietary fiber. In this study, the effect of red ginseng dietary fiber (RGDF) on the growth of probiotic bacterial strains was investigated at the phenotypic and genetic levels. Methods: We performed transcriptome profiling of Lactiplantibacillus plantarum IDCC3501 in two phases of culture (logarithmic (L)-phase and stationary (S)-phase) in two culture conditions (with or without RGDF) using RNA-seq. Differentially expressed genes (DEGs) were identified and classified according to Gene Ontology terms. Results: The growth of L.plantarum IDCC3501 was enhanced in medium supplemented with RGDF up to 2%. As a result of DEG analysis, 29 genes were upregulated and 30 were downregulated in the RGDF-treated group in the L-phase. In the S-phase, 57 genes were upregulated and 126 were downregulated in the RGDF-treated group. Among the upregulated genes, 5 were upregulated only in the L-phase, 10 were upregulated only in the S-phase, and 3 were upregulated in both the L- and S-phases. Conclusions: Transcriptome analysis could be a valuable tool for elucidating the molecular mechanisms by which RGDF promotes the proliferation of L.plantarum IDCC3501. This growth-promoting effect of RGDF is important, since RGDF could be used as a prebiotic source without additional chemical or enzymatic processing.

• 한국동물위생학회지
• /
• 제45권4호
• /
• pp.277-284
• /
• 2022

Salmonella is a pathogenic bacterium that has long been important industrially because it has a wide host range and can be transmitted to humans through direct contact as well as indirect contact such as food contaminated with animal waste. Understanding how to reduce Salmonella contamination in pig farms is important for public health and the livestock industry from an economic perspective. In the swine industry, high concentrations of disinfectants have been applied because it is difficult to effectively control Salmonella in environments contaminated with organic substances. In order to evaluate the synergetic effect of disinfectants, the efficacy of two commercial disinfectants diluted in hard water and microbubble water (MBW) were compared under the laboratory condition. Different concentrations of both disinfectants combined with 1% detergent diluted in the two diluents were evaluated for their antibacterial effect. In the case of monopersulfate-based disinfectant groups, the growth of Salmonella was not observed at 1:200 dilution with both the hard water and MBW combined with 1% detergent. In the case of citric acid-based disinfectant, the bacterial growth was not observed at 1:800 dilution with MBW combined with 1% detergent. Our results show that the use of MBW as a diluent might improve the biological activities of acid-based disinfectant.

• Journal of Microbiology and Biotechnology
• /
• 제33권1호
• /
• pp.96-105
• /
• 2023

Probiotic supplements have promising therapeutic effects on chronic diseases. In this study, we demonstrated the anti-obesity effects of two potential probiotics, Bifidobacterium bifidum DS0908 (DS0908) and Bifidobacterium longum DS0950 (DS0950). Treatment with DS0908 and DS0950 postbiotics significantly induced the expression of the brown adipocyte-specific markers UCP1, PPARγ, PGC1α, PRDM16 and beige adipocyte-specific markers CD137, FGF21, P2RX5, and COX2 in C3H10T1/2 mesenchymal stem cells (MSCs). In mice with high-fat diet (HFD)-induced obesity, both potential probiotics and postbiotics noticeably reduced body weight and epididymal fat accumulation without affecting food intake. DS0908 and DS0950 also improved insulin sensitivity and glucose use in mice with HFD-induced obesity. In addition, DS0908 and DS0950 improved the plasma lipid profile, proved by reduced triglyceride, low-density lipoprotein, and cholesterol levels. Furthermore, DS0908 and DS0950 improved mitochondrial respiratory function, confirmed by the high expression of oxidative phosphorylation proteins, during thermogenesis induction in the visceral and epididymal fat in mice with HFD-induced obesity. Notably, the physiological and metabolic changes were more significant after treatment with potential probiotic culture-supernatants than those with the bacterial pellet. Finally, gene knockdown and co-treatment with inhibitor-mediated mechanistic analyses showed that both DS0908 and DS0950 exerted anti-obesity-related effects via the PKA/p38 MAPK signaling activation in C3H10T1/2 MSCs. Our observations suggest that DS0908 and DS0950 could potentially alleviate obesity as dietary supplements.

• 식물병연구
• /
• 제28권4호
• /
• pp.195-203
• /
• 2022

Zea mays, known as maize or corn, is a major staple crop and an important source of energy for humans and animals, thus ensuring global food security. Approximately 9.4% of the loss of total annual corn production is caused by pathogens including fungi, bacteria, and viruses, resulting in economic losses. Although the use of fungicides is one of the most common strategies to control corn diseases, the frequent use of fungicides causes various health problems in humans and animals. In order to overcome this problem, an eco-friendly control strategy has recently emerged as an alternative way. One such eco-friendly control strategy is the use of beneficial microorganisms in the control of plant pathogens. The beneficial microorganisms can control the plant pathogens in various ways, such as spatial competition with plant pathogens, inhibition of fungal or bacterial growth via the production of secondary metabolites or antibiotics, and direct attack to plant pathogens via enzyme activity. Here, we reviewed microorganisms as biocontrol agents against corn diseases.

• Animal Bioscience
• /
• 제36권4호
• /
• pp.671-678
• /
• 2023

Objective: Previous studies isolated the thermophilic ammonium-tolerant (TAT) bacterium Bacillus sp. TAT105 that grew in composting swine manure with the assimilation of ammonium nitrogen and reduced ammonia emissions during composting. Those studies also investigated the potential for applications of TAT105 to composting. It was observed that the concentration of TAT bacteria, phylogenetically close to TAT105, increased during composting. The objectives of this study were to identify the phylogenetic placement of these TAT bacteria and investigate their distribution in various composts. Methods: The phylogenetic placement of TAT105 was examined based on the sequence of 16S ribosomal RNA gene. The genomic DNA homology between TAT105 and the type strains of bacterial species that were phylogenetically close to TAT105 were examined by DNA-DNA hybridization. Moreover, the tolerances of these strains to NH₄Cl and NaCl were analyzed using a cultivation method. Concentrations of TAT bacteria in various composts were evaluated using an agar medium specific to TAT bacteria and polymerase chain reaction followed by restriction fragment length polymorphism analysis. Results: TAT105 was most closely related to Bacillus thermolactis and Bacillus kokeshiiformis. Many variants of these species have been detected in various environments, including composts. The type strains of these species displayed TAT characteristics that were similar to those of TAT105. Among the composts examined in this study, TAT bacteria were detected at high concentrations (10⁵ to 10⁹ colony forming units per gram of dry matter) in most of the composts made from cattle manure, swine manure, bark, and excess sludge. Conclusion: TAT bacteria comprised B. thermolactis, B. kokeshiiformis, and their phylogenetically close relatives. They were considered to be adaptable to composting of some certain materials, and a favorable target for searching for strains with some useful function that could be applied to composting of these materials.

• 한국환경과학회지
• /
• 제31권3호
• /
• pp.265-274
• /
• 2022

Lipoxygenase is an enzyme, mainly produced by plants, capable of converting unsaturated fatty acids to fatty acids. It has vast application potential in the food, pharmaceutical and agricultural industries. The aim of this study was to isolate novel lipoxygenase-producing bacteria from the environment and to investigate the lipoxygenase enzymatic properties for industrial production. The strain, NC1, isolated from cultivation soils, was identified as Bacillus subtilis based on the phenotypic characteristics and 16S rRNA gene sequencing. This strain formed a pink color around the colony when cultured on indamine dye formation plates. The production of lipoxygenase by B. subtilis NC1 was influenced by the composition of the medium and linoleic acid concentrations. The optimum temperature and pH for lipoxygenase activity was determined to be 40 ℃ and pH 6, respectively. The enzyme showed relatively high stability at temperatures ranging from 20-50 ℃ and acid-neutral regions. In addition, the lipoxygenase produced by B. subtilis NC1 was able to degrade commercially available oils including sunflower seed oil and Perilla oil. In this study, a useful indigenous bacterium was isolated, and the fundamental physicochemical data of bacterial lipoxygenase giving it industrial potential are presented.

• Advances in nano research
• /
• 제14권4호
• /
• pp.391-397
• /
• 2023

This manuscript describes the one-step eco-friendly green fabrication of silver nanoparticles (AgNPs) through the in-situ bio-reduction of an aqueous solution of silver nitrate using Syzygium aromaticum leaf extract. UV-vis spectroscopy shows a characteristic SPR peak around 442 nm. FTIR spectroscopy showed that the AgNPs were capped with bioactive phyto-molecules. TEM images revealed oval and spherical particles with a mean diameter of ~12.6 nm. XRD analysis revealed crystalline and face-cantered cubic AgNPs. The phytosynthesized AgNPs showed broad-spectrum anti-microbial activity against two foodborne pathogenic bacteria, Listeria monocytogenes and Staphylococcus aureus. The AgNPs showed a prominent ability to inhibit biofilms formed by L. monocytogenes and S. aureus in laboratory conditions through a crystal violet assay. The results suggest that the AgNPs could be a novel nanotool to develop effective antimicrobial and anti-biofilm agents in food preservation.