• Journal of Veterinary Science
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• v.25 no.2
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• pp.30.1-30.16
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• 2024

Background: Biofilms, such as those from Staphylococcus epidermidis, are generally insensitive to traditional antimicrobial agents, making it difficult to inhibit their formation. Although quercetin has excellent antibiofilm effects, its clinical applications are limited by the lack of sustained and targeted release at the site of S. epidermidis infection. Objectives: Polyethylene glycol-quercetin nanoparticles (PQ-NPs)-loaded gelatin-N,O-carboxymethyl chitosan (N,O-CMCS) composite nanogels were prepared and assessed for the on-demand release potential for reducing S. epidermidis biofilm formation. Methods: The formation mechanism, physicochemical characterization, and antibiofilm activity of PQ-nanogels against S. epidermidis were studied. Results: Physicochemical characterization confirmed that PQ-nanogels had been prepared by the electrostatic interactions between gelatin and N,O-CMCS with sodium tripolyphosphate. The PQ-nanogels exhibited obvious pH and gelatinase-responsive to achieve on-demand release in the micro-environment (pH 5.5 and gelatinase) of S. epidermidis. In addition, PQ-nanogels had excellent antibiofilm activity, and the potential antibiofilm mechanism may enhance its antibiofilm activity by reducing its relative biofilm formation, surface hydrophobicity, exopolysaccharides production, and eDNA production. Conclusions: This study will guide the development of the dual responsiveness (pH and gelatinase) of nanogels to achieve on-demand release for reducing S. epidermidis biofilm formation.

• Journal of Microbiology and Biotechnology
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• v.34 no.3
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• pp.562-569
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• 2024

Xanthomonas oryzae pv. oryzae (Xoo) causes a devastating bacterial leaf blight in rice. Here, the antimicrobial effects of ᴰ-limonene, ᴸ-limonene, and its oxidative derivative carveol against Xoo were investigated. We revealed that carveol treatment at ≥ 0.1 mM in liquid culture resulted in significant decrease in Xoo growth rate (> 40%) in a concentration-dependent manner, and over 1 mM, no growth was observed. The treatment with ᴰ-limonene and ᴸ-limonene also inhibited the Xoo growth but to a lesser extent compared to carveol. These results were further elaborated with the assays of motility, biofilm formation and xanthomonadin production. The carveol treatment over 1 mM caused no motilities, basal level of biofilm formation (< 10%), and significantly reduced xanthomonadin production. The biofilm formation after the treatment with two limonene isomers was decreased in a concentration-dependent manner, but the degree of the effect was not comparable to carveol. In addition, there was negligible effect on the xanthomonadin production mediated by the treatment of two limonene isomers. Field emission-scanning electron microscope (FE-SEM) unveiled that all three compounds used in this study cause severe ultrastructural morphological changes in Xoo cells, showing shrinking, shriveling, and holes on their surface. Moreover, quantitative real-time PCR revealed that carveol and ᴰ-limonene treatment significantly down-regulated the expression levels of genes involved in virulence and biofilm formation of Xoo, but not with ᴸ-limonene. Together, we suggest that limonenes and carveol will be the candidates of interest in the development of biological pesticides.

• Journal of Food Hygiene and Safety
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• v.31 no.6
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• pp.451-457
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• 2016

The purpose of this study was to determine the antimicrobial effects of $ClO_2$ gas on pathogenic E. coli and Salmonella spp. colonizing on the fruit surface of strawberries for export. Factorial design was employed to treat strawberries inoculated with pathogenic E. coli or Salmonella spp. with a combination of $ClO_2$ gas concentrations (10, 20, 30, 40, and 50 ppmv), RH (50, 70, and 90%), and treatment time (0, 5, 10, 20, and 30 min). Interaction between the factors was observed to note that the reduced levels of microbial population were the highest when RH is set at 90% with gas concentration- and treatment time-dependent manner. With RH and gas concentration fixed at 90% and 50 ppmv, the populations of E. coli and Salmonella spp. decreased by 2.07 and 2.28 log CFU/g when treated for 20 min whereas population reduction by 0.5 and 0.7 log CFU/g were observed when treated for 5 min, respectively. The results help establish most effective conditions for $ClO_2$ gas treatment to enhance microbial safety of strawberries for export.

• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.586-592
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• 2015

This study was performed to determine optimum approaches for control of microorganisms in school refectories and kitchens. A reduction of more than 5.0 log CFU/mL was noted for Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Streptococcus mutans after treatment with 5 ppm ozone water for 60 s. Treatment of different vegetables with ozone water for 5 min showed bactericidal effects with 2-4 log reduction of viable cell number; the bactericidal effects differed according to the kinds of vegetables. The viable cell number on kitchen apparatus and tableware was not detected by ozone water treatment for 60 s. In addition, the count of the bacteria floating in the air in refectories and kitchens decreased 2.0 log CFU/1,000 L air to 0-1 CFU/1,000 L air on treatment with 45 ppm ozone gas for 12 hr. Therefore, ozone water and ozone gas may be good candidates as antimicrobial agents that can be used to improve sanitary conditions in school refectories and kitchens.

• Journal of Life Science
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• v.18 no.12
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• pp.1693-1699
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• 2008

Recent studies have suggested that inulin might be utilized as a prebiotics for the promotion of antimicrobial growth, but a major obstacle to the use of inulin has been its low bifidogenic effects, which were initially observed in the ceca of broiler chickens. Inulin has some problems with related to denaturation in air and lowering passage rate from upper digestive tract to caecum. To solve this problems, a newly developed compound derived by microencapsulation, inuloprebiotics, was hypothesized to enrich cecal bifidobacterial populations and reduce the colonization levels of Salmonella in the ceca of broiler chickens. The in vitro growth of intestinal beneficial bacteria including Bifidobacterium longum, Bifidobacterium bifidum, Lactobacillus acidophilus, and Lactobacillus casei grew effectively on the medium containing inulin, whereas the growth of Streptococcus aureus and Clostridium perfringens was not differences among the treatment groups. Broiler chickens consumed chow diets containing 0.5%, 0.7% or 1.0% inuloprebiotics, or a control diet without inuloprebiotics supplementation. The chickens on the inuloprebioticssupplemented diets evidenced significantly higher cecal levels of Bifidobacterium and Lactobacillus species as compared with the chickens on the control diet. The population of cecal E. coli and Salmonella was specifically reduced as the result of treatment with inuloprebiotics. However, we noted no significant differences in Bifidobacterium species, E. coli and Salmonella counts among the inuloprebiotics treatment groups. The inuloprebiotics-supplemented diets induced an increase in the serum IgG concentration. The thymus index was significantly increased in the broiler chickens that consumed diets containing 0.7% or 1.0% inuloprebiotics, with the exception of the chickens consuming the diet supplemented with 0.5% inuloprebiotics. These results indicate that the inuloprebiotic preparations exerted an immune system-promoting effect or selectively enriched the cecal Bifidobacterium species populations in the broiler chickens, and also suggest that inuloprebiotics may prove useful as a stable natural antimicrobial agent.

• Journal of Animal Environmental Science
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• v.13 no.1
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• pp.45-52
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• 2007

To evaluate the feed value of starfish, antimicrobial effects of its extract, nutrients contents, concentration of amino acids and its bioavailability were tested. Steaming and ether processes were applied to obtain the extract from starfish for antimicrobial effects examination. The starfish was dried at $60^{\circ}C$ for 3 days before grinding for processing and fermentation. Ground starfish(GS), extruded starfish(ES), fermented starfish(EFS) were added with enzyme and without enzyme(Non enzyme fermented starfish : NEFS). Then the nutrient composition and bioavailability of those were analyzed. The extract from starfish showed no inhibition of the growth of lactobacillus and pathogenic bacteria. Protein content showed significantly higher 62.86% and 52.82%, respectively in EFS and NEFS than GS and EGS(p<0.05). The Ca content of GS, EGS, EFS and NEFS was 17.26%, 18.26%, 5.37% and 8.55%, respectively. It was low in EFS and NEFS due to measure the Ca content after fermentation. Total amino acid was 17.17 mg/g, 20.28 mg/g, 36.30 mg/g and 29.96 mg/g in GS, EGS, EFS and NEFS, respectively. The ratio of total amino acid to protein tended to show the similar tendency as total amino acid. Both total amino acid and its ratio to protein were increased by the fermentation. Bioavailability of the protein and Ca showed more 80% in EFS and NEFS. The nutrients availability of EFS were significantly higher in laying hens than other treatments. The results of these experiments indicate that starfish would be applied as a feed ingredients if it was properly treated.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.6
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• pp.1026-1038
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• 1995

Although aloe lost a lot of its previous popularity in modern clinical uses as medicine numerous scientific researches still have claimed the beneficial properties(curing and general tonic effect) of aloe gel. Whereas considerable contradictory reports have helped to confuse the aloe gel issue and continually aroused controversy about aloe gel efficacy. However health food, cosmetic and medicinal products made from aloe gel are widely available in the world market especially in U.S.A. so the growing of Aloe plant and the processing of A. vera gel have become big industries in some countries. In some previous papers the salicylic acid, one of the common trace gel components, was thought to have an analgetic and antinflammatory effect. Large amount of Mg ion in the gel was suggested to act as anesthetic, Mg-lactate as antihistamic, and Aloctin A(a glycoprotein) as wound healer by promoting the cell growth. The carboxypeptidase and bradykinase activity in the gel were proposed to have the pain relieving and antiinflammatory effect. But any of thes etheories concerining the physiological action of the trace gel components has not been demonstrated by modern pharmacology, and failed to be supported by clinical research. It was suggested by some research workers that trace amount of anthraquinone compounds in the gel play an important role to act as false substrate inhibitors for PG and TX production(antiprostanoid effect), by which, they believed, inflammation, burn and frostbite, and infected wound could be healed. This hypothesis has not been substantiated. Butthe suggested antimicrobial action, antidiabetic, and antidotic effect of aloe gel are likely to be attributed to the trace anthraquinone compounds. In a lot of recent experimental reports it has been claimed that aloe gel polysaccharides(acetylglucomannan, acetylmannan, and glycoprotein) have the antimicrobial, antinflammatory, antitumour, and infected wound healing effect by immunoenhancement. It is hoped that these effects will be soon documented in clinical studies, then the controversy on aloe gel beneficial effect will cease. In the 30 days subchronic toxicity test the lowest observed adverse effect level of acemannan(acetylmannan) on dog was 5.0 mg/kg, IP. But the aloe gel is generally agreed to be harmless and non toxic even for the internal use such as health food. In the case of idiosynrasy one must keep the delayed type hypersensitivity reaction of aloe gel in mind. In conclusion it seem to be impossible to simply refuse a lot of evidences made by research workers who have claimed aloe gel's beneficial effects and to deny the fact that there had been long therapeutic histories of Aloe plants.

• Journal of Life Science
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• v.31 no.11
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• pp.987-994
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• 2021

Our previous studies have reported that antimicrobial peptides (AMPs) derived from the larvae of white-spotted flower chafer (Protaetia brevitarsis seulensis) exert anti-inflammatory and neuroprotective activities. This study explored the anti-inflammatory effects of protaetiamycine 9 (CVLKKAYFLTNLKLRG-NH₂), a novel AMP, derived from P. b. seulensis against lipopolysaccharide (LPS)-mediated inflammatory response in RAW264.7 macrophage cells. Protaetiamycine 9 (25, 50, 75, and 100 ㎍/ml) did not cause cytotoxic effects against RAW264.7 cells. The RAW264.7 cells were pre-treated with various concentrations of protaetiamycine 9 (25-100 ㎍/ml) for 1 hr and then exposed to LPS (100 ng/ml) for 24 hr. Protaetiamycine 9 treatments decreased the LPS-induced secretion of inflammatory mediators, such as nitric oxide (NO), in a dose-dependent manner. Protaetiamycine 9 (25-100 ㎍/ml) effectively downregulated the LPS-induced increase in mRNA and the protein expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), which are involved in the production of inflammatory mediators. Protaetiamycine 9 also suppressed the production and gene expression of pro-inflammatory cytokines, including interleukin (IL)-6 and IL-1β, compared to the presence of LPS alone. Furthermore, protaetiamycine 9 inhibited the degradation of inhibitory kappa B alpha (IκB-α) and the phosphorylation of mitogen-activated protein kinases (MAPKs), such as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38. In conclusion, these results suggest that protaetiamycine 9 exhibits LPS-mediated inflammatory responses by blocking IκB-α degradation and MAPK phosphorylation.

• Journal of Life Science
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• v.33 no.12
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• pp.1015-1024
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• 2023

Antibiotics have greatly contributed to the treatment and prevention of bacterial diseases in humans, animals, and fish. However, antibiotic misuse has led to the emergence and spread of multidrug-resistant bacteria. In addition to antibiotic discovery research, efforts are being made to combat such multidrug-resistant bacteria using antimicrobial agents, antioxidants, host immune enhancement, probiotics, and bacteriophages, as well as various symptomatic therapies. To discover novel bioactive compounds, it is crucial to adopt approaches that incorporate fresh ideas, new targets, innovative techniques, and untapped resources. Halophytes are plants that grow in high-salt soils and are known to adapt to salt-induced stress through unique metabolic processes that produce secondary metabolites. This study aimed to investigate the effects of extracts of halophytes native to Korea on oxidative stress and to determine whether they exert inhibitory activity against biofilms, which are major pathogenic factors of infectious bacteria. The Acinetobacter baumannii strain ATCC 17978, a representative drug-resistant bacterium, was used to measure anti-biofilm activity. The results showed that Aster spathulifolius, Carex kobomugi, Rosa rugosa, and Asparagus cochinchiensis exerted strong antioxidant and anti-biofilm effects without affecting bacterial growth itself. The halophytes used in this study are promising candidates for the development of pharmaceutical agents with antioxidant and antimicrobial properties.

• Korean Journal of Ichthyology
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• v.26 no.3
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• pp.171-178
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• 2014

Myogenesis is the formation process of multinucleated myofiber with a contractile capacity from muscle satellite cell (MSCs) during life. This process is tightly controlled by several transcription factors such as Pax3 and Pax7 (paired box protein 3 and 7), MEF2C (myocyte enhancer factor 2) and MRFs (myogenic regulatory factors) etc. On the contrary, myostatin (MSTN) is a transforming growth factor-${\beta}$ superfamily, which functions as a negative regulator of skeletal muscle development and growth. Carnosic acid (CA) is a major phenolic component in rosemary (Rosmarinus officinalis) and have been reported various biological activities such as anticancer, antioxidant, antimicrobial and therapeutic agents for amnesia, dementia, alzheimer's disease. This study was confirmed to effects of CA on muscle cell line and muscle tissue alteration of zebrafish by intramuscular injection or feeding methods. $10{\mu}M$ CA showed a non-cytotoxic on myoblast and a complete inhibition effect against myostatin activity on luciferase assay. In intramuscular injection experiment, the total protein and triglyceride amount of $10{\mu}M/kg$ of CA injected group increased by 11% and decreased by 13% compared to these of the no injected group. In histology analysis of muscle tissues by hematoxylin/eosin staining, the number of muscle fiber of $10{\mu}M/kg$ of CA injected group decreased by 29% and fiber area increased 40% compared to these of no injected group. In feeding experiment, the total protein and triglyceride amount no significance difference compared to these of the normal feeding group. In histology analysis, the number of muscle fiber of 1% CA fed group decreased by 35% and fiber area increased 56% compared to these of normal fed group. We identified that CA have an effect on hypertrophy of muscle fiber in adult zebrafish and the results of this study are considered as the basic data that can reveal the mechanisms of muscle formation via gene and protein level analysis.