Ja-Young Jang

Weissella cibaria WIKIM28 ameliorates atopic dermatitis-like skin lesions by inducing tolerogenic dendritic cells and regulatory T cells in BALB/c mice.

The occurrence of atopic dermatitis (AD), a chronic inflammatory skin disease, has been increasing steadily in children and adults in recent decades. In this study, we evaluated the ability of the lactic acid bacterium Weissella cibaria WIKIM28 isolated from gatkimchi, a Korean fermented vegetable preparation made from mustard leaves, to suppress the development of AD induced by 2,4-dinitrochlorobenzene in a murine model. Oral administration of W. cibaria WIKIM28 reduced AD-like skin lesions, epidermal thickening, and serum immunoglobulin E levels. Furthermore, the production of type 2 helper T (Th2) cytokines such as interleukin (IL)-4, IL-5, and IL-13 decreased in peripheral lymph node cells. Moreover, the intake of W. cibaria WIKIM28 increased the proportion of CD4+CD25+Foxp3+ regulatory T (Treg) cells in mesenteric lymph nodes (MLNs) and IL-10 levels in polyclonally stimulated MLN cells. In conclusion, the oral administration of W. cibaria WIKIM28 isolated from gatkimchi ameliorated AD-like symptoms by suppressing allergic Th2 responses and inducing Treg responses. These results suggest that W. cibaria WIKIM28 may be applicable as a probiotic for the prevention and amelioration of AD.

Extending the shelf life of kimchi with Lactococcus lactis strain as a starter culture

Lactococcus lactis subsp. lactis WK11 was introduced as a starter in kimchi fermentation to investigate the role of starter cultures in extending the shelf life of kimchi. Kimchi, with an initial inoculum size of 107 CFU/g as well as control kimchi without the starter culture, were prepared and fermented for 56 days at 8°C. The addition of L. lactis prolonged the optimal fermentation period (pH 4.2, acidity 0.6–0.8%) up to more than 2 times. The starter culture, L. lactis WK11, persisted throughout the kimchi fermentation, as confirmed by regular monitoring of the L. lactis population by PCR-DGGE. Taken together, our results suggest that L. lactis starter culture may be useful for extending the shelf-life of kimchi without adverse effects of kimchi with a longer shelf life.

Protective effect of soy powder and microencapsulation on freeze-dried Lactobacillus brevis WK12 and Lactococcus lactis WK11 during storage

Food-grade cryoprotective agents, i.e., skim milk, soy powder, yeast extract, and trehalose were tested for viability of lactic acid bacteria (LAB, Lactobacillus brevis WK12 and Lactococcus lactis WK11) during freeze drying. Ten percentage of soy powder showed a strong protective effect upon viability of both LAB, showing 1.85×1011 CFU/mL for L. brevis WK12 and 1.89×1011 CFU/mL for L. lactis WK11. Microencapsulation in Ca-alginate beads increased viability of LAB, compared to nonencapsulated cells. Moreover, there was a synergetic effect on the stability of LAB when encapsulated LAB in Ca-alginate beads were soaked in 10% of soy powder prior to freeze-drying. When temperature increased, however, survival of LAB decreased. Four weeks after storage the highest viability was observed at -18°C for L. brevis WK12 and L. lactis WK11, showing 1.80×1011 CFU/mL and 1.78×1011 CFU/mL, respectively. These results suggest that soy powder may be useful for enhancing viability of LAB with microencapsulation.

Optimization of Herbicidin A Production in Submerged Culture of Streptomyces scopuliridis M40

Herbicidin A is a potent herbicide against dicotyledonous plants as well as an antibiotic against phytopathogens. In this study, fermentation parameters for herbicidin A production in submerged culture of Streptomyces scopuliridis M40 were investigated. The herbicidin A concentration varied with the C/N ratio. High C/N ratios (>4) resulted in a herbicidin A production of more than 900 mg/l, whereas maximally 600 mg/l was obtained at ratios between 1 and 3.5. In 5-L batch fermentation, there was a positive correlation between the oxygen uptake rate (OUR) and herbicidin A production. Once the OUR increased, the substrate consumption rate increased, leading to an increase in volumetric productivity. Mechanical shear force affected the hyphal morphology and OUR. When the medium value of hyphal size ranged from 150 to 180 μm, high volumetric production of herbicidin A was obtained with OUR values >137 mg O2/l·h. The highest herbicidin A concentration of 956.6 mg/l was obtained at 500 rpm, and coincided with the highest relative abundance of hyphae of 100-200 μm length and the highest OUR during cultivation. Based on a constant impeller tip speed, which affects hyphal morphology, herbicidin A production was successfully scaled up from a 5-L jar to a 500-L pilot vessel.

Gracilibacillus kimchii sp. nov., a halophilic bacterium isolated from kimchi

A novel halophilic bacterium, strain K7T, was isolated from kimchi, a traditional Korean fermented food. The strain is Gram-positive, motile, and produces terminal endospores. The isolate is facultative aerobic and grows at salinities of 0.0–25.0% (w/v) NaCl (optimum 10–15% NaCl), pH 5.5–8.5 (optimum pH 7.0–7.5), and 15–42°C (optimum 37°C). The predominant isoprenoid quinone in the strain is menaquinone-7 and the peptidoglycan of the strain is meso-diaminopimelic acid. The major fatty acids of the strain are anteisio-C15:0, iso-C15:0, and, C16:0 (other components were < 10.0%), while the major polar lipids are diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, and three unidentified lipids. A phylogenetic analysis of 16S rRNA gene sequence similarity showed that the isolated strain was a cluster of the genus Gracilibacillus. High levels of gene sequence similarity were observed between strain K7T and Gracilibacillus orientalis XH-63T (96.5%), and between the present strain and Gracilibacillus xinjiangensis (96.5%). The DNA G+C content of this strain is 37.7 mol%. Based on these findings, strain K7T is proposed as a novel species: Gracilibacillus kimchii sp. nov. The type strain is K7T (KACC 18669T; JCM 31344T).

Safety Evaluation of Heavy Metal in Salted Vegetable Foods from Diverse Origin in Korea

ABSTRACT - This study was conducted to estimate the contents of heavy metals in salted vegetable foods fromdiverse origin in Korea which were sold in Korea. The levels of heavy metals were determined using an ICP-MS. Thevalues of metals [minimum~maximum (mean), mg/kg] in kimchi were as follows; Pb 0.0~0.074(0.018), Cd 0.0~0.027(0.004), As 0.0~0.024(0.002), Hg 0~0.002(0.0). The weekly average intakes of lead, cadmium, arsenic and mercuryfrom kimchi take 0.06~0.13% PTWI (Provisional Tolerable Weekly Intakes) that the FAO/WHO Joint Food Additiveand Contaminants Committee has set to evaluate their safeties. Key words : Safety, Fermented vegetable foods, lead, cadmium 중금속은 비중이 4 이상 되는 금속원소로서 86종 가량이 있으며, 이들 중 약 27종만이 생체의 기능유지에 필수적이며, 필요량에서 부족하거나 다량일 경우 건강상의 장해를 일으킨다. 대다수의 금속은 영양학적으로 무의미하며 그 중에서 동·식물체에 유해성이 큰 중금속으로는 수은(Hg), 카드뮴(Cd), 납(Pb), 비소(As), 주석(Sn), 아연(Zn),구리(Cu), 크롬(Cr), 망간(Mn) 등이 이에 해당한다. 이들금속의 농도, 존재하는 화학성, 배설 속도, 건강 상태 등다양한 인자에 따라 생체에서의 유해 여부에 차이가 있다. 그런데 중금속은 자신이 가지고 있는 독성뿐만 아니라 축적성이 있어 먹이 연쇄에 따라 크게 농축된다. 특히, 수은, 카드뮴, 납은 식품 중에서 공통적으로 볼 수 있는 독성 물질로 생체 조직과 강한 결합을 하여 생체 내에서 축적되어 천천히 제거되는 유해 금속이다

Salicibibacter kimchii gen. nov., sp. nov., a moderately halophilic and alkalitolerant bacterium in the family Bacillaceae, isolated from kimchi

A moderately halophilic and alkalitolerant bacterial strain NKC1-1T was isolated from commercial kimchi in Korea. Strain NKC1-1T was Gram-stain-positive, aerobic, rod-shaped, non-motile, and contained diaminopimelic acid-type murein. Cell growth was observed in a medium containing 0–25% (w/v) NaCl (optimal at 10% [w/v]), at 20–40°C (optimal at 37°C) and pH 6.5–10.0 (optimal at pH 9.0). The major isoprenoid quinone of the isolate was menaquinone-7, and the major polar lipids were phosphatidylglycerol and unidentified phospholipids. Cell membrane of the strain contained iso-C17:0 and anteiso-C15:0 as the major fatty acids. Its DNA G + C content was 45.2 mol%. Phylogenetic analysis indicated the strain to be most closely related to Geomicrobium halophilum with 92.7–92.9% 16S rRNA gene sequence similarity. Based on polyphasic taxonomic evaluation with phenotypic, phylogenetic, and chemotaxonomic analyses, the strain represents a novel species in a new genus, for which the name Salicibibacter kimchii gen. nov., sp. nov. is proposed (= CECT 9537T; KCCM 43276T).

Lactobacillus sakei WIKIM30 Ameliorates Atopic Dermatitis-Like Skin Lesions by Inducing Regulatory T Cells and Altering Gut Microbiota Structure in Mice

Lactobacillus sakei WIKIM30 is a Gram-positive facultative anaerobic bacterium isolated from kimchi, a Korean fermented vegetable food. In this study, we found that WIKIM30 promoted regulatory T cell (Treg) differentiation by inducing dendritic cells with tolerogenic properties. The production of the T helper (Th) 2-associated cytokine interleukin (IL)-4 was decreased, but that of the Treg-associated cytokine IL-10 was increased in splenocytes from ovalbumin-sensitized mice treated with WIKIM30. We also investigated the inhibitory capacity of WIKIM30 on the development of 2,4-dinitrochlorobenzene-induced atopic dermatitis (AD), a Th2-dominant allergic disease in mice. Oral administration of L. sakei WIKIM30 significantly reduced AD-like skin lesions and serum immunoglobulin E and IL-4 levels while decreasing the number of CD4+ T cells and B cells and the levels of Th2 cytokines (IL-4, IL-5, and IL-13) in peripheral lymph nodes and enhancing Treg differentiation and IL-10 secretion in mesenteric lymph nodes. In addition, WIKIM30 modulated gut microbiome profiles that were altered in AD mice, which showed increases in Arthromitus and Ralstonia and a decrease in Ruminococcus abundance. These changes were reversed by WIKIM30 treatment. Notably, the increase in Ruminococcus was highly correlated with Treg-related responses and may contribute to the alleviation of AD responses. Together, these results suggest that oral administration of L. sakei WIKIM30 modulates allergic Th2 responses enhancing Treg generation and increases the relative abundance of intestinal bacteria that are positively related to Treg generation, and therefore has therapeutic potential for the treatment of AD.