• The Plant Pathology Journal
• /
• v.35 no.2
• /
• pp.91-99
• /
• 2019

Mitogen-activated protein kinase (MAPK) cascades in fungi are ubiquitously conserved signaling pathways that regulate stress responses, vegetative growth, pathogenicity, and many other developmental processes. Previously, we reported that the AbSte7 gene, which encodes a mitogen-activated protein kinase kinase (MAPKK) in Alternaria brassicicola, plays a central role in pathogenicity against host cabbage plants. In this research, we further characterized the role of AbSte7 in the pathogenicity of this fungus using ${\Delta}AbSte7$ mutants. Disruption of the AbSte7 gene of A. brassicicola reduced accumulation of metabolites toxic to the host plant in liquid culture media. The ${\Delta}AbSte7$ mutants could not efficiently detoxify cruciferous phytoalexin brassinin, possibly due to reduced expression of the brassinin hydrolase gene involved in detoxifying brassinin. Disruption of the AbSte7 gene also severely impaired fungal detoxification of reactive oxygen species. AbSte7 gene disruption reduced the enzymatic activity of cell walldegrading enzymes, including cellulase, ${\beta}$-glucosidase, pectin methylesterase, polymethyl-galacturonase, and polygalacturonic acid transeliminase, during host plant infection. Altogether, the data strongly suggest the MAPKK gene AbSte7 plays a pivotal role in A. brassicicola during host infection by regulating multiple steps, and thus increasing pathogenicity and inhibiting host defenses.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.10
• /
• pp.1092-1097
• /
• 2009

A novel exopolysaccharide named Ebosin was produced by Streptomyces sp. 139, with medicinal activity. Its biosynthesis gene cluster (ste) has been previously identified. For the functional study of the ste7 gene in Ebosin biosynthesis, it was disrupted with a double crossover via homologous recombination. The monosaccharide composition of EPS-7m produced by the mutant strain Streptomyces sp. 139 ($ste7^-$) was found altered from that of Ebosin, with fucose decreasing remarkably. For biochemical characterization of Ste7, the ste7 gene was cloned and expressed in Escherichia coli BL21. With a continuous coupled spectrophotometric assay, Ste7 was demonstrated to have the ability of catalyzing the transfer of fucose specifically from GDP-$\beta$-L-fucose to a fucose acceptor, the lipid carrier located in the cytoplasmic membrane of Streptomyces sp. 139 ($ste7^-$). Therefore, the ste7 gene has been identified to code for a fucosyltransferase, which plays an essential role in the formation of repeating sugars units during Ebosin biosynthesis.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.11
• /
• pp.1500-1508
• /
• 2013

Ebosin, a novel exopolysaccharide produced by Streptomyces sp. 139, has obvious antirheumatic arthritis activity in vivo, and its biosynthesis gene cluster (ste), consisting of 27 open reading frames, has been identified. This paper reports our study of the gene functionality of ste8, the predicted protein product of which is homologous to some bacterial chain length determinant Wzz proteins. For characterization of Ste8, ste8 was cloned and expressed in the mutant strain E. coli 086:H2 (${\Delta}wzz$). The functional complementation of wzz by ste8 was demonstrated by the restoration of wild-type lipopolysaccharide biosynthesis and increased levels of serum resistance of E. coli 086:H2 (${\Delta}wzz$) (pET30a-ste8). To examine the function of ste8 in ebosin biosynthesis, the gene was knocked out with a double crossover via homologous recombination. The molecular weight of the ebosin derivative EPS-8m produced by the mutant Streptomyces sp. 139 ($ste8^-$) was much lower than that of ebosin, and the binding activity of EPS-8m for IL-1R decreased significantly compared with ebosin. These results demonstrate that ste8 encodes a chain length determinant (Wzz) that functions in ebosin biosynthesis.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.7
• /
• pp.1311-1319
• /
• 2016

Alternaria brassicicola (Schwein.) invades Brassicaceae and causes black spot disease, significantly lowering productivity. Mitogen-activated protein kinases (MAPKs) and their upstream kinases, including MAPK kinases (MAPKKs) and MAPKK kinases (MAPKKK), comprise one of the most important signaling pathways determining the pathogenicity of diverse plant pathogens. The AbSte7 gene in the genome of A. brassicicola was predicted to be a homolog of yeast Ste7, a MAPKK; therefore, the function was characterized by generating null mutant strains with a gene replacement method. AbSte7 replacement mutants (RMs) had a slower growth rate and altered colony morphology compared with the wild-type strain. Disruption of the AbSte7 gene resulted in defects in conidiation and melanin accumulation. AbSte7 was also involved in the resistance pathways in salt and oxidative stress, working to negatively regulate salt tolerance and positively regulate oxidative stress. Pathogenicity assays revealed that AbSte7 RMs could not infect intact cabbage leaves, but only formed very small lesions in wounded leaves, whereas typical lesions appeared on both intact and wounded leaves inoculated with the wild-type strain. As the first studied MAPKK in A. brassicicola, these data strongly suggest that the AbSte7 gene is an essential element for the growth, development, and pathogenicity of A. brassicicola.

• Food Science and Biotechnology
• /
• v.16 no.5
• /
• pp.858-862
• /
• 2007

The present study was conducted to examine the antioxidant activities and neuroprotective effects of methanolic extracts from Schizonepeta tenuifolia Briquet (STE). STE ($100\;{\mu}g/mL$) showed $43.33\;{\mu}M$ of total phenolic content, 64.43% of radical scavenging activity, and 0.157 of reducing power. In addition, the effect of STE on $H_2O_2$-induced DNA damage in human leucocytes was evaluated by the comet assay, where STE was a dose dependent inhibitor of DNA damage induced by $200{\mu}M$ of $H_2O_2$. The protective effect of STE against $H_2O_2$-induced oxidative damage on PC12 cells was investigated by an 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) reduction assay and lactate dehydrogenase (LDH) release assays. After 2 hr of cell exposure to $H_2O_2\;(500\;{\mu}M)$, a marked reduction in cell survival was observed. However, this reduction was significantly prevented by $1-50\;{\mu}g/mL$ of STE. Therefore, these results suggest that STE could be a new antioxidant candidate against neuronal diseases.

• YAKHAK HOEJI
• /
• v.48 no.2
• /
• pp.165-170
• /
• 2004

The production of matrix metalloproteinases (MMPs) by the UV irradiated skin fibroblast and the degradation of extracellular matrix (ECM) by these enzymes is known as one of the main reasons of photoaging. In this paper, to investigate the relationship between aging and Selaginella tamariscina extract (STE), we investigated the effects of antioxidant and expression of UVA-induced MMP-1 in human dermal fibroblasts. STE was found to show scavenging activities of radicals and reactive oxygen species (ROS) with the $IC_{50}$/ values of 65.1 $\mu\textrm{g}$/$m\ell$ against 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical and 40.9 $\mu\textrm{g}$/$m\ell$ against superoxide radicals in the xanthine/xanthine oxidase system, respectively. UVA induced MMP expression was reduced 75.5% by treatment with STE, and MMP-1 mRNA expression was reduced in a dose-dependent manner. Therefore STE was able to significantly inhibition of MMP expression in protein and mRNA level. All these results suggested that STE may act as an anti-aging agent by antioxidation and reducing UVA-induced MMP-1 production.

• Journal of the Korean Society of Physical Medicine
• /
• v.12 no.1
• /
• pp.25-33
• /
• 2017

PURPOSE: The initiation of the trunk muscles in stroke patients is delayed because the muscles involved in reach arm are activated earlier than the trunk muscles. The objective of this study was to examine the effects of mobility, balance, and trunk control ability through selective trunk exercise (STE) in patients with chronic stroke. METHODS: A randomized pre-test and post-test control group design was initially used, with subjects randomly assigned to the STE group (n=15) and a control group (n=14). All groups underwent physical therapy based on the neuro-developmental therapy (NDT) for 30 minutes a day, five times per week for four weeks. Additionally, the STE group did the trunk exercise for 30 minutes a day, three times per week for four weeks. The timed up and go test (TUG), Berg balance scale (BBS), and trunk impairment scale (TIS) were used for assessment. RESULTS: The scores of the TUG, BBS, dynamic sitting balance subscale, and coordination subscale of TIS improved significantly in both groups but the improvement was more pronounced in the STE group (p<.05). This study showed a large effect on the scores of the TIS coordination subscale (d=.93) (p<.05), TIS dynamic balance subscale (d=.81) (p<.05), TUG (d=.75) (p<.05), and BBS (d=.73) (p<.05). CONCLUSION: The combined STE and NDT program showed improvements in measures of mobility, balance, and trunk control in chronic stroke patients. These results suggest that STE should be considered to be included in the treatment program for patients with chronic stroke.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.52 no.3
• /
• pp.193-198
• /
• 2019

Natural seasoning are trends of food industries to replace synthesized seasoning due to consumer preference. However, unexpected results can be happened in a point of sensory evaluation and physico-chemical properties by adding natural seasoning such as reduced flavor, color change and so on. Therefore, this study aimed to verify the potential of sea tangle Saccharina japonica extract fermented by lactic acid bacteria (STE) for myungran (pollock roe)-jeot instead of present synthesized seasoning. Among various STE concentration (0%, 5%, 10%, and 15%) in myungranjeot, there was no significant physicochemical changes in a point of crude lipid, pH, total acidity, salinity and color difference. Microbiological profiles was also not significantly different. The 10% STE-myungran-jeot showed higher ${\gamma}$-aminobutyric acid (GABA) content as 24.4 mg/100g at free amino acid analysis than other STE-myungran-jeot without decline of sensory properties. In overall, it revealed that STE could replace the synthesized seasoning and improve the quality of Myungran-jeot. The results suggest that STE can be useful to develop a Korean traditional fermented food.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.11
• /
• pp.969-973
• /
• 2018

Avionics OFP runs on the mission computer and can be operated by interacting with several avionics equipments. In order to verify OFP SW, SIL having real avionics equipments or models is absolutely necessary. Therefore in many cases SIL is implemented concurrently with OFP developing, and only one SIL is provided to developers. So developers sometimes need an alternative to SIL for verifying requirements in the middle of development process. In this paper, we propose a single PC based STE SW that simulates interworking equipments and verifies OFP in a single PC environment without actual interworking equipments or SIL HW interfaces.

• Korean Journal of Microbiology
• /
• v.47 no.2
• /
• pp.110-116
• /
• 2011

In the previous study with the Saccharomyces cerevisiae S288c strains, no known function of the dual specificity kinase, ScKns1, was reported because its gene deletion did not show any noticeable phenotypic changes. Recent study with fission yeast, however, revealed the involvement of the LAMMER kinase in flocculation, filamentous growth, oxidative stress, and so on. Therefore we made Sckns1-deletion mutants with the ${\Sigma}1278b$-background, with which one can induce filamentous and adhesive growth in contrast to those of the S288c-background. The $Sckns1{\Delta}$ strains of both haploid and diploid showed defect in filamentous growth under conditions for inducing the filamentous growth such as nitrogen starvation and butanol treatment. Both kinds of the deletion mutants also showed decrease in adhesive growth on agar surface. Interestingly enough the defects of the $Sckns1{\Delta}$ strains were suppressed by the over-expression of each gene for the components of the MAPK signaling pathway such as STE11, STE12, and TEC1, respectively, but not by the upstream components, RAS2 and STE20, respectively. Although further investigations are required, these results indicate that the ScKns1 may act in place between the Ste20 and the Ste11 of the S. cerevisiae MAPK cascade.