Biology subjects

Kwon, S.-W.

Publications and source records attributed to Kwon, S.-W..

3 recordsLinked to original sources

bioRxiv2022

Production of novel biosurfactant by a new yeast species isolated from Prunus mume Sieb. et Zucc.

Biosurfactants reduce surface and interfacial tension due to their amphiphilic properties, and are an eco-friendly alternative for chemical surfactants. In this study, a novel yeast strain JAF-11 that produces biosurfactant was selected using drop collapse method, and the properties of the material were investigated. The nucleotide sequences of the strain were compared with closely related strains and identified based on the D1/D2 domain of the large-subunit rDNA (LSU) and internal transcribed spacer (ITS) regions. Neodothiora populina CPC 39399T, the closest species with strain JAF-11 in the phylogenetic tree, showed a sequence similarity of 97.75% for LSU and 94.27% for ITS, respectively. The result suggests that the strain JAF-11 represent a distinct species which cannot be assigned to any existing genus or species in the family Dothideaceae. Strain JAF-11 was able to produce biosurfactant reducing the surface tension of medium to 34.5 mN/m on the 6th day of culture and the result of measuring the critical micelle concentration (CMC) by extracting the crude biosurfactant was found to be 24 mg l-1. The molecular weight 502 of the purified biosurfactant was confirmed by measuring the fast atom bombardment mass spectrum (FAB-MS). The chemical structure was analyzed by measuring 1H nuclear magnetic resonance (NMR), 13C NMR, two-dimensional NMRs of the compound. The molecular formula was C26H46O9, and it was composed of one octanoyl group and two hexanoyl group to myo-inositol moiety. The new biosurfactant is the first report of a compound produced by a novel yeast strain JAF-11. This new biosurfactant is proposed as potential candidate for use in a variety field.

microbiology↗

bioRxiv2021

A new protocol for speed vernalisation of winter cereals

There are many challenges facing the development of high-yielding, nutritious crops for future environments. One limiting factor is generation time, which prolongs research and plant breeding timelines. Recent advances in speed breeding protocols have dramatically reduced generation time for many short-day and long-day species by optimising light and temperature conditions during plant growth. However, winter crops with a vernalisation requirement still require up to 6-10 weeks in low-temperature conditions before transition to reproductive development. Here, we tested a suite of environmental conditions and protocols to investigate if vernalisation can be satisfied more efficiently. We identified a vernalisation method consisting of exposing seeds at the soil surface to an extended photoperiod of 22 h day:2 h night at 10{degrees}C with transfer to speed breeding conditions that dramatically reduces generation time in both winter wheat (Triticum aestivum) and winter barley (Hordeum vulgare). Implementation of this protocol achieved up to five generations per year for winter wheat or barley, instead of the two typically obtained under standard vernalisation and plant growth conditions. The protocol has great potential to enhance training and to accelerate research, pre-breeding, and breeding outcomes focussed on winter crop improvement.

plant biology↗

bioRxiv2019

Unveiling the crucial role of type IV secretion system and motility of Helicobacter pylori in IL-1β production via NLRP3 inflammasome activation in neutrophils

Helicobacter pylori is a gram-negative, microaerophilic, and spiral-shaped bacterium and causes gastrointestinal diseases in human. IL-1{beta} is a representative cytokine produced in innate immune cells and is considered to be a key factor in the development of gastrointestinal malignancies. However, the mechanism of IL-1{beta} production by neutrophils during H. pylori infection is still unknown. We designed this study to identify host and bacterial factors involved in regulation of H. pylori-induced IL-1{beta} production in neutrophils. We found that H. pylori-induced IL-1{beta} production is abolished in NLRP3-, ASC-, and caspase-1/11-deficient neutrophils, suggesting essential role for NLRP3 inflammasome in IL-1{beta} response against H. pylori. Host TLR2, but not TLR4 and Nod2, was also required for transcription of NLRP3 and IL-1{beta} as well as secretion of IL-1{beta}. H. pylori lacking cagL, a key component of the type IV secretion system (T4SS), induced less IL-1{beta} production in neutrophils than did its isogenic WT strain, whereas vacA and ureA were dispensable. Moreover, T4SS was involved in caspase-1 activation and IL-1{beta} maturation in H. pylori-infected neutrophils. We also found that FlaA is essential for H. pylori-mediated IL-1{beta} production in neutrophils, but not dendritic cells. TLR5 and NLRC4 were not required for H. pylori-induced IL-1{beta} production in neutrophils. Instead, bacterial motility is essential for the production of IL-1{beta} in response to H. pylori. In conclusion, our study shows that host TLR2 and NLRP3 inflammasome and bacterial T4SS and motility are essential factors for IL-1{beta} production by neutrophils in response to H. pylori.\n\nIMPORTANCEIL-1{beta} is a representative pro-inflammatory cytokine and is considered to be a central host factor for the development of gastric cancers. Although neutrophils have been considered to be involved in H. pylori-induced gastric inflammation, the underlying mechanism by which H. pylori triggers IL-1{beta} production in neutrophils remains to be defined. In this study, our data suggested a critical role for the host TLR2 and NLRP3 inflammasome in IL-1{beta} production by neutrophil during H. pylori infection. Moreover, we found the bacterial factors, T4SS and FlaA, to be essential for IL-1{beta} production and NLRP3 activation during the course of H. pylori infection. Our current findings provide detailed molecular genetic mechanisms associated with IL-1{beta} production in neutrophils in response to H. pylori infection, which can serve as innovative anti-inflammatory targets to reduce H. pylori-induced gastric malignancies.

immunology↗