• 한국식품영양과학회지
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• 제23권5호
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• pp.856-862
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• 1994

In salt-preserved foods of every kinds, it was examined the growth condition of halophilic bacteria that induced a change of colour, taste, nutritive substance, a production condition of enzyme and a character of crude enzyme. Used bacteria is H. halobium a kind of extremely halophilic bacteria, and the required of optimum culture needed a quite long time of crude enzyme production is 168 hours. Optimum pH is about 7-7.5, so the traditional food of such neutrality pH as soybean paste and soy sauce particularly come into trouble because the growth can flourish in neutrality or alkaliescence, and the crude enzyme also appeared that best activation between pH 6 and pH 8. The optimum temperature is about 37$^{\circ}C$, the optimum temperature of enzyme is about 40 $^{\circ}C$ and the temperature stability is settled for 15 minutes and it is completely inactivated at 10 minutes. In the influence of each metal ion, Fe++ and Mn++ a stimulated the growth of H.halobium and the activation of enzyme, Cu++ and Zn++ were identified that made the growth and the activation of enzyme inhibit.

• Journal of Microbiology and Biotechnology
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• 제14권3호
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• pp.503-508
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• 2004

The antimicrobial substance produced by Lactobacillus bulgaricus was inactivated by protease. It showed inhibitory activity against Staphylococcus aureus ATCC6538, Streptococcus agalactiae ATCC14364, some Gram-positive and Gram-negative bacteria, and characteristics of a bacteriocin. The optimal temperature and culture time for the production of bacteriocin were $30^{\circ}C$ and 10 h, respectively, in the culture of L. bulgaricus. The bacteriocin production started in the exponential phase and reached a maximum at the early stationary phase. Using Staph. aureus ATCC6538 and Strep. agalactiae ATCC14364, known as common bovine mastitis pathogens, as indicator strains for determination of the bacteriocin activity, the antimicrobial activity of the bacteriocin was found to be stable in acidic and neutral pH's (2- 7) even at lOOT, whereas it was lost at high pH (10- 11) and $100^{\circ}C$. The mode of action for the antimicrobial activity was bacteriocidal, and the molecular weight determined by SDS-PAGE and overlay method was 14 kDa.

• 식물병연구
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• 제24권2호
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• pp.162-169
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• 2018

The GacS/GacA system in the root colonizer Pseudomonas chlororaphis O6 is a key regulatory system of many traits relevant to the plant probiotic nature of this bacterium. The work in this paper elucidates proteins using proteomics approach in P. chlororaphis O6 under the control of the cytoplasmic regulatory protein, GacA. A gacA mutant of P. chlororaphis O6 showed loss in production of phenazines, acyl homoserine lactones, hydrogen cyanide, and protease, changes that were associated with reduced in vitro antifungal activity against plant fungal pathogens. Production of iron-chelating siderophore was significantly enhanced in the gacA mutant, also paralleling changes in a gacS mutant. However, proteomic analysis revealed proteins (13 downregulated and 7 upregulated proteins in the mutant compared to parental strain) under GacA control that were not apparent by a proteomic study of a gacS mutant. The putative identity of the downregulated proteins suggested that a gacA mutant would have altered transport potentials. Notable would be a predicted loss of type-VI secretion and PEP-dependent transport. Study of mutants of these GacA-regulated proteins will indicate further the features required for probiotic potential in this rhizobacterium.

• 한국환경과학회지
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• 제29권3호
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• pp.249-255
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• 2020

Particulate matter with an aerodynamic diameter of less than 2.5 μM (PM_2.5) is one of the major environmental pollutants. Di(2-ethylhexyl) phthalate (DEHP), an endocrine disrupting chemical in PM_2.5, has been utilized for the manufacturing of polyvinyl chloride to increase the flexibility of final products. In the present study, we investigated the ecotoxicological effect of DEHP on the viability of skin keratinocytes (HaCaT). DEHP induced apoptotic cell death mediated by phosphorylation of extracellular signal-regulated kinase through the production of intracellular Reactive Oxygen Species (ROS). Interestingly, we found that DEHP induces the phosphorylation of the nuclear factor-kappa B responsible for the expression of cleaved caspase-3 as an executional cell death protease in HaCaT cells. On the basis of these results, we suggest that DEHP in PM_2.5 induces the apoptotic death of human keratinocytes via ROS-mediated signaling events.

• 한국미생물·생명공학회지
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• 제52권1호
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• pp.55-64
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• 2024

The desire of modern people to maintain a healthy and beautiful appearance is increasing day by day along with the increasing interest in skin health and the demand for functional cosmetics. Accordingly, research on functional cosmetic materials with few side effects and excellent efficacy is being actively conducted. Therefore, this study tried to verify the antioxidant and whitening effects of the mixed extracts of Bixa orellana, Ammi majus, and Glycyrrhiza glabra, whose efficacy has been individually verified. Extracts (BAG-1~4) with different extraction methods such as steaming, fermentation, and ultrasonication were prepared for 3 types of natural plants, and antioxidant and whitening effects of these extracts were confirmed. For this purpose, antioxidant, tyrosinase activity, melanin production and stability experiments were conducted. Extracts (BAG-1~4) had no cytotoxicity, and antioxidant and whitening effects were confirmed. BAG-4 extracted by steaming and fermentation showed the best efficacy. It seems that enzymes such as lipase, protease, and amylase increase phenol components by various yeasts involved in the fermentation process, thereby improving antioxidant and melanin production inhibitory effects. It was confirmed that the three types of natural plant extracts could be used as safe and functional cosmetic materials.

• 한국환경과학회지
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• 제22권11호
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• pp.1457-1464
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• 2013

We investigated the optimal conditions for keratinase production by feather-degrading Pseudomonas geniculata H10 using one variable at a time (OVT) method. The optimal medium composition and cultural condition for keratinase production were determined to be glucose 0.15% (w/v), beef extract 0.08% (w/v), $KH_2PO_4$ 0.12% (w/v), $K_2HPO_4$ 0.02% (w/v), NaCl 0.07% (w/v), $MgSO_4{\cdot}7H_2O$ 0.03%, $MgCl_2{\cdot}6H_2O$ 0.04% along with initial pH 10 at 200 rpm and $25^{\circ}C$, respectively. The production yield of keratinase was 31.6 U/ml in an optimal condition, showing 4.6-fold higher than that in basal medium. The strain H10 also showed plant growth promoting activities. This strain had ammonification activity and produced indoleacetic acid (IAA), siderophore and a variety of hydrolytic enzymes such as protease, lipase and chitinase. Therefore, this study showed that P. geniculata H10 could be not only used to upgrade the nutritional value of feather wastes but also useful in situ biodegradation of feather wastes. Moreover, it is also a potential candidate for the development of biofertilizing agent applicable to crop plant soil.

• Asian-Australasian Journal of Animal Sciences
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• 제33권5호
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• pp.753-762
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• 2020

Objective: The aim of the present study was to determine the effect of supplementing pasture-finished steers with corn silage on the expression level of the calpain system proteins and beef tenderization. Methods: Thirty Braford steers grazing on summer pasture were used for the study. For 120 days fifteen animals were supplemented with corn silage at 1% of body weight per head per day (Suppl) whereas the remaining 15 steers only received pasture (Contr). Carcass and meat traits were evaluated and compared between groups. Gene expression and activities of proteases (calpain 1 and calpain 2) and inhibitor (calpastatin) were measured using real-time polymerase chain reaction and casein zymography. Results: Carcass and meat traits were significantly different between feeding systems. Supplemented steers showed higher hot carcass weight (p<0.01), fat content (p = 0.02), and Warner-Bratzler shear force (p = 0.03). Furthermore, the control group showed higher protease:inhibitor ratios, at mRNA (p = 0.01) and protein levels (p<0.10). Warner-Bratzler shear force and mRNA calpains:calpastatin ratio were associated in both feeding systems (p<0.01). Conclusion: Based on the results obtained in the study, beef tenderness differences among finishing strategies could be modulated through differential expression of the calpain system proteins.

• The Plant Pathology Journal
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• 제35권6호
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• pp.674-683
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• 2019

Some species of the Trichoderma genus are reported as the major problem in oak wood mushroom production in Korea. In spite of economic loss by the fungi, scientific information on airborne Trichoderma species is not much available. To generate information for disease management development we analyzed airborne Trichoderma. A total of 1,063 fungal isolates were purely obtained from indoor air sampling of cultivation houses used for oak wood mushroom using sawdust media. Among the obtained isolates, 248 isolates were identified as Trichoderma fungi including T. harzianum, T. atroviride, T. citrinoviride, and T. pseudokoningii, by morphological and molecular analysis. T. harzianum was dominant among the four identified species. All the four Trichoderma species grew fast on solid nutrient media tested (potato dextrose agar [PDA], malt extract agar [MEA], Czapek's Dox + yeast extract agar [CYA] and cornmeal dextrose agar). Compact mycelia growth and mass spore production were better on PDA and CYA. In addition, T. harzianum and T. citrinoviride formed greenish and yellowish mycelium and spores on PDA and CYA. Greenish and yellowish pigment was saturated into PDA only by T. pseudokoningii. These four Trichoderma species could produce extracellular enzymes of sawdust substrate degradation such as β-glucosidase, avicelase, CM-cellulase, amylase, pectinase, xylanase, and protease. Their mycelia inhibited the growth of oak wood mushroom mycelia of two tested cultivars on dual culture assay. Among of eleven antifungal agents tested, benomyl was the best to inhibit the growth of the four Trichoderma species. Our results demonstrate that the airborne Trichoderma fungi need to be properly managed in the cultivation houses for safe mushroom production.

• Journal of Microbiology and Biotechnology
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• 제20권11호
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• pp.1577-1584
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• 2010

In total, 140 halotolerant bacterial strains were isolated from both the soil of barren fields and the rhizosphere of six naturally growing halophytic plants in the vicinity of the Yellow Sea, near the city of Incheon in the Republic of Korea. All of these strains were characterized for multiple plant growth promoting traits, such as the production of indole acetic acid (IAA), nitrogen fixation, phosphorus (P) and zinc (Zn) solubilization, thiosulfate ($S_2O_3$) oxidation, the production of ammonia ($NH_3$), and the production of extracellular hydrolytic enzymes such as protease, chitinase, pectinase, cellulase, and lipase under in vitro conditions. From the original 140 strains tested, on the basis of the latter tests for plant growth promotional activity, 36 were selected for further examination. These 36 halotolerant bacterial strains were then tested for 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity. Twenty-five of these were found to be positive, and to be exhibiting significantly varying levels of activity. 16S rRNA gene sequencing analyses of the 36 halotolerant strains showed that they belong to 10 different bacterial genera: Bacillus, Brevibacterium, Planococcus, Zhihengliuella, Halomonas, Exiguobacterium, Oceanimonas, Corynebacterium, Arthrobacter, and Micrococcus. Inoculation of the 14 halotolerant bacterial strains to ameliorate salt stress (150 mM NaCl) in canola plants produced an increase in root length of between 5.2% and 47.8%, and dry weight of between 16.2% and 43%, in comparison with the uninoculated positive controls. In particular, three of the bacteria, Brevibacterium epidermidis RS15, Micrococcus yunnanensis RS222, and Bacillus aryabhattai RS341, all showed more than 40% increase in root elongation and dry weight when compared with uninoculated salt-stressed canola seedlings. These results indicate that certain halotolerant bacteria, isolated from coastal soils, have a real potential to enhance plant growth under saline stress, through the reduction of ethylene production via ACC deaminase activity.

• The Plant Pathology Journal
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• 제28권4호
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• pp.439-445
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• 2012

The chitinase producing Lysobacter enzymogenes C-3 has previously been shown to suppress plant pathogens in vitro and in the field, but little is known of the regulation of chitinase production, or its role in antimicrobial activity and biocontrol. In this study, we isolated and characterized chitinase-defective mutants by screening the transposon mutants of L. enzymogenes C-3. These mutations disrupted genes involved in diverse functions: glucose-galactose transpoter (gluP), disulfide bond formation protein B (dsbB), Clp protease (clp), and polyamine synthase (speD). The chitinase production of the SpeD mutant was restored by the addition of exogenous spermidine or spermine to the bacterial cultures. The speD and clp mutants lost in vitro antifungal activities against plant fungal pathogens. However, the gluP and dsbB mutants showed similar antifungal activities to that of the wild-type. The growth of the mutants in nutrient rich conditions containing chitin was similar with that of the wild-type. However, growth of the speD and gluP mutants was defective in chitin minimal medium, but was observed no growth retardation in the clp and dsbB mutant on chitin minimal medium. In this study, we identified the four genes might be involved and play different role in the production of extracellular chitinase and antifungal activity in L. enzymogenes C-3.