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57 result(s) for "Choi, Yeong Bin"
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Development and application of a high-performance liquid chromatography diode-array detection (HPLC–DAD) method for the simultaneous quantification of phenolic compounds in the aerial part of Glehnia littoralis
Glehnia littoralis, a medicinal herb employed in traditional practices for alleviating fatigue, cough, and a dry throat, is recognized for its beneficial properties due to a diverse array of active compounds found in its extracts. For example, the G. littoralis roots (Radix Glehniae) mainly contain coumarins and phenolic acids, serving as the primary focus of this study. Despite the widespread use of the tools in various industries and the development of multiple analytical methods for their examination, the edible aerial parts have industrial potential, and there is currently no analytical method available to identify their key components. In this study, a high-performance liquid chromatography method combined with diode array detection (HPLC–DAD) was developed to simultaneously detect 16 phenolic compounds previously reported to be present in the edible aerial parts of G. littoralis. The proposed approach included using gradient elution to change the solvent system from water/acetonitrile to water/methanol. Furthermore, the method validation was conducted, assessing its linearity, limit of detection, limit of quantification, precision, accuracy, and recovery, all of which demonstrated satisfactory results. Subsequently, the developed method was applied to quantify the phenolic compounds in various G. littoralis samples obtained from different organs, solvent extraction processes, and processing methods. Moreover, the online HPLC-ABTS (2,2ʹ-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) assay was used to evaluate the antioxidant capacities of individual constituents, identifying four important antioxidants and estimate the overall antioxidant capacity of the G. littoralis extract.
Correlation analysis between artemisinin and its derivative contents and trichome characteristics from different Artemisia species
Artemisia species have significant commercial, medical, and economic value and are widely used in the traditional medicine and pharmaceutical industries. Artemisinin, a powerful antimalarial agent, is an important pharmaceutical metabolite that primarily accumulates within the glandular trichomes (GTs) on the leaf surface of Artemisia plants. Trichomes arising from the elongation of epidermal cells can be classified into GTs and non-glandular trichomes (NGTs) based on their morphology. GTs and NGTs are present in Artemisia species, and the relationship between GTs and artemisinin has been extensively studied; however, the correlation between NGTs and artemisinin remains relatively unexplored. In this study, we inferred artemisinin derivatives and trichome characteristics based on the type of species, developmental stage, and leaf age and conducted correlation analyses to investigate the factors influencing artemisinin content across different Artemisia species. Artemisinin and its derivatives exhibited variations in distribution based on species and leaf age, with a decreasing trend observed across most species as the developmental stage progressed. Noticeable differences among Artemisia species were observed in leaf shape, morphology, and trichome distribution. Although the observed data did not evidently differentiate between species, developmental stage, and leaf age groups, principal component analysis revealed that artemisinin was positively associated with the NGTs density, indicating a correlation coefficient of 0.56 (p < 0.0001). Therefore, the number of NGTs may affect the artemisinin content in different Artemisia species.
Myrosinase isogenes in wasabi (Wasabia japonica Matsum) and their putative roles in glucosinolate metabolism
Background Wasabi, a Brassicaceae member, is well-known for its unique pungent and hot flavor which is produced from glucosinolate (GSL) degradation. Myrosinase (MYR) is a principle enzyme catalyzing the primary conversion of GSLs to GSL hydrolysis products (GHPs) which is responsible for plant defense system and food quality. Due to the limited information in relation to MYRs present in wasabi ( Wasabia japonica M.), this study aimed to identify the MYR isogenes in W. japonica and analyze their roles in relation to GSL metabolism. Results In results, WjMYRI-1 was abundantly expressed in all organs, whereas WjMYRI-2 showed only trace expression levels. WjMYRII was highly expressed in the aboveground tissues. Interestingly, WjMYRII expression was significantly upregulated by certain abiotic factors, such as methyl jasmonate (more than 40-fold in petioles and 15-fold in leaves) and salt (tenfold in leaves). Young leaves and roots contained 97.89 and 91.17 µmol‧g −1 of GSL, whereas less GSL was produced in mature leaves and petioles (38.36 and 44.79 µmol‧g −1 , respectively). Similar pattern was observed in the accumulation of GHPs in various plant organs. Notably, despite the non-significant changes in GSL production, abiotic factors treated samples enhanced significantly GHP content. Pearson’s correlation analysis revealed that WjMYRI-1 expression significantly correlated with GSL accumulation and GHP formation, suggesting the primary role of WjMYRI-1 -encoding putative protein in GSL degradation. In contrast, WjMYRII expression level showed no correlation with GSL or GHP content, suggesting another physiological role of WjMYRII in stress-induced response. Conclusions In conclusions, three potential isogenes ( WjMYRI-1 , WjMYRI-2 , and WjMYRII ) encoding for different MYR isoforms in W. japonica were identified. Our results provided new insights related to MYR and GSL metabolism which are important for the implications of wasabi in agriculture, food and pharmaceutical industry. Particularly, WjMYRI-1 may be primarily responsible for GSL degradation, whereas WjMYRII (clade II) may be involved in other regulatory pathways induced by abiotic factors.
Understanding the Impact of Nitrogen Availability: A Limiting Factor for Enhancing Fucoxanthin Productivity in Microalgae Cultivation
This study aimed to investigate the regulation of fucoxanthin (FX) biosynthesis under various nitrogen conditions to optimize FX productivity in Phaeodactylum tricornutum. Apart from light, nitrogen availability significantly affects the FX production of microalgae; however, the underlying mechanism remains unclear. In batch culture, P. tricornutum was cultivated with normal (NN, 0.882 mM sodium nitrate), limited (LN, 0.22 mM), and high (HN, 8.82 mM) initial nitrogen concentrations in f/2 medium. Microalgal growth and photosynthetic pigment production were examined, and day 5 samples were subjected to fucoxanthin–chlorophyll a/c-binding protein (FCP) proteomic and transcriptomic analyses. The result demonstrated that HN promoted FX productivity by extending the exponential growth phase for higher biomass and FX accumulation stage (P1), showing a continuous increase in FX accumulation on day 6. Augmented FX biosynthesis via the upregulation of carotenogenesis could be primarily attributed to enhanced FCP formation in the thylakoid membrane. Key proteins, such as LHC3/4, LHCF8, LHCF5, and LHCF10, and key genes, such as PtPSY, PtPDS, and PtVDE, were upregulated under nitrogen repletion. Finally, the combination of low light and HN prolonged the P1 stage to day 10, resulting in maximal FX productivity to 9.82 ± 0.56 mg/L/day, demonstrating an effective strategy for enhancing FX production in microalgae cultivation.
Physiological Effects and Mechanisms of Chlorella vulgaris as a Biostimulant on the Growth and Drought Tolerance of Arabidopsis thaliana
Microalgae have demonstrated biostimulant potential owing to their ability to produce various plant growth-promoting substances, such as amino acids, phytohormones, polysaccharides, and vitamins. Most previous studies have primarily focused on the effects of microalgal biostimulants on plant growth. While biomass extracts are commonly used as biostimulants, research on the use of culture supernatant, a byproduct of microalgal culture, is scarce. In this study, we aimed to evaluate the potential of Chlorella vulgaris culture as a biostimulant and assess its effects on the growth and drought tolerance of Arabidopsis thaliana, addressing the gap in current knowledge. Our results demonstrated that the Chlorella cell-free supernatant (CFS) significantly enhanced root growth and shoot development in both seedlings and mature Arabidopsis plants, suggesting the presence of specific growth-promoting compounds in CFS. Notably, CFS appeared to improve drought tolerance in Arabidopsis plants by increasing glucosinolate biosynthesis, inducing stomatal closure, and reducing water loss. Gene expression analysis revealed considerable changes in the expression of drought-responsive genes, such as IAA5, which is involved in auxin signaling, as well as glucosinolate biosynthetic genes, including WRKY63, MYB28, and MYB29. Overall, C. vulgaris culture-derived CFS could serve as a biostimulant alternative to chemical products, enhancing plant growth and drought tolerance.
A Noble Extract of Pseudomonas sp. M20A4R8 Efficiently Controlling the Influenza Virus-Induced Cell Death
Epidemic diseases that arise from infectious RNA viruses, particularly influenza viruses, pose a constant threat to the global economy and public health. Viral evolution has undermined the efficacy of acquired immunity from vaccines and the antiviral effects of FDA-approved drugs. As such, there is an urgent need to develop new antiviral lead agents. Natural compounds, owing to their historical validation of application and safety, have become a promising solution. In this light, a novel marine bacterium, Pseudomonas sp. M20A4R8, has been found to exhibit significant antiviral activity [half maximal inhibitory concentration (IC50) = 1.3 µg/mL, selectivity index (SI) = 919.4] against influenza virus A/Puerto Rico/8/34, surpassing the activity of chloroquine. The antiviral response via M20A4R8 extract was induced during post-entry stages of the influenza virus, indicating suitability for post-application after the establishment of viral infection. Furthermore, post-treatment with M20A4R8 extract protected the host from virus-induced apoptosis, suggesting its potential use in acute respiratory disease complexes resulting from immune effectors’ overstimulation and autophagy-mediated self-apoptosis. The extract demonstrated an outstanding therapeutic index against influenza virus A/Wisconsin/15/2009 (IC50 = 8.1 µg/mL, SI = 146.2) and B/Florida/78/2015 Victoria lineage (IC50 = 3.5 µg/mL, SI = 343.8), indicating a broad anti-influenza virus activity with guaranteed safety and effectiveness. This study provides a new perspective on mechanisms for preventing a broad spectrum of viral infections through antiviral agents from novel and natural origins. Future studies on a single or combined compound from the extract hold promise, encouraging its use in preclinical challenge tests with various influenza virus strains.
Longitudinal multiomic profiling and corticosteroid modulation of the immediate innate immune response to an adenovirus-vector vaccine
Longitudinal multiomic (single cell transcriptome/TCR/BCR, CD14 + ATAC) immune landscape following ChAdOx1 nCoV-19 vaccination. Monocyte and innate-like T cell populations expressing interferon-stimulated genes increased 1 day post-vaccination, returning to baseline by day 14. Pre-treatment with oral corticosteroids effectively curtailed these inflammatory responses without hampering vaccine immunogenicity. [Display omitted] Among new vaccine technologies contributed to the control of the COVID-19 pandemic, ChAdOx1 nCoV-19, a chimpanzee adenovirus (ChAd)-vector vaccine expressing the SARS-CoV-2 spike protein, could be administered globally owing to its low production cost and lack of a requirement for frozen storage. Despite its benefits, most recipients have reported immediate inflammatory reactions after the initial dose vaccination. We comprehensively examined the immune landscape following ChAdOx1 nCoV-19 vaccination based on the single-cell transcriptomes of immune cells and epigenomic profiles of monocytes. Monocyte and innate-like activated T cell populations expressing interferon-stimulated genes (ISGs) increased 1 day post-vaccination with appearance of distinct subtype of ISG-activated cells, returning to baseline by day 14. Pre-treatment with oral corticosteroids effectively curtailed these ISG-associated inflammatory responses by decreasing chromatin accessibility of major ISGs, without hampering vaccine immunogenicity. Our findings provide insights into the human immune response following ChAd-based vaccination and propose a method to reduce inflammatory side effects.
Therapeutic Potential of a Novel Bifidobacterium Identified Through Microbiome Profiling of RA Patients With Different RF Levels
The potential therapeutic effects of probiotic bacteria in rheumatoid arthritis (RA) remain controversial. Thus, this study aimed to discover potential therapeutic bacteria based on the relationship between the gut microbiome and rheumatoid factor (RF) in RA. Bacterial genomic DNA was extracted from the fecal samples of 93 RA patients and 16 healthy subjects. Microbiota profiling was conducted through 16S rRNA sequencing and bioinformatics analyses. The effects of Bifidobacterium strains on human peripheral blood mononuclear cells and collagen-induced arthritis (CIA) mice were assessed. Significant differences in gut microbiota composition were observed in patients with different RF levels. The relative abundance of Bifidobacterium and Collinsella was lower in RF-high than in RF-low and RF-negative RA patients, while the relative abundance of Clostridium of Ruminococcaceae family was higher in RF-high than in RF-low and RF-negative patients. Among 10 differentially abundant Bifidobacterium , B. longum RAPO exhibited the strongest ability to inhibit IL-17 secretion. Oral administration of B. longum RAPO in CIA mice, obese CIA, and humanized avatar model significantly reduced RA incidence, arthritis score, inflammation, bone damage, cartilage damage, Th17 cells, and inflammatory cytokine secretion. Additionally, B. longum RAPO significantly inhibited Th17 cells and Th17-related genes— IL-17A , IRF4 , RORC , IL-21 , and IL-23R —in the PBMCs of rheumatoid arthritis patients. Our findings suggest that B. longum RAPO may alleviate RA by inhibiting the production of IL-17 and other proinflammatory mediators. The safety and efficacy of B. longum RAPO in patients with RA and other autoimmune disorders merit further investigation.
Artificially designed recombinant protein composed of multiple epitopes of foot-and-mouth disease virus as a vaccine candidate
Background Concerns regarding the safety of inactivated foot-and-mouth disease (FMD) vaccine have been raised since it is produced from cultured live FMD virus (FMDV). To overcome this issue, recombinant protein has been studied as an alternative vaccine. Results and conclusion We designed a chimerical multi-epitope recombinant protein (5BT), which is comprised of tandem repeats of five B cell epitopes (residue of VP1 136–162) derived from different FMDV variants and one T-cell epitope (residue of 3A 21–35). To increase solubility and stability of 5BT, it was conjugated with BmpB, the membrane protein B of Brachyspira hyodysenteriae (B5BT). Our results indicated that 5BT was susceptible to degradation by host protease and produced with substantial fraction of inclusion body. The stability and solubility of 5BT was greatly increased by conjugating to BmpB. FMDV specific antibodies were observed in the serum of mice immunized with 5BT and B5BT comparable to inactivated FMD vaccine. Sera from 5BT and B5BT groups also exhibited high epitope-specific antibody titers in peptide specific ELISA, indicating that all five epitopes are exposed to the B cell receptor for the antibody reaction. Thus the multi-epitope recombinant protein designed in this study may be a potential candidate as an alternative vaccine against FMDV epidemic variants.
Activation of PI3K, Akt, and ERK during early rotavirus infection leads to V-ATPase-dependent endosomal acidification required for uncoating
The cellular PI3K/Akt and/or MEK/ERK signaling pathways mediate the entry process or endosomal acidification during infection of many viruses. However, their roles in the early infection events of group A rotaviruses (RVAs) have remained elusive. Here, we show that late-penetration (L-P) human DS-1 and bovine NCDV RVA strains stimulate these signaling pathways very early in the infection. Inhibition of both signaling pathways significantly reduced production of viral progeny due to blockage of virus particles in the late endosome, indicating that neither of the two signaling pathways is involved in virus trafficking. However, immunoprecipitation assays using antibodies specific for pPI3K, pAkt, pERK and the subunit E of the V-ATPase co-immunoprecipitated the V-ATPase in complex with pPI3K, pAkt, and pERK. Moreover, Duolink proximity ligation assay revealed direct association of the subunit E of the V-ATPase with the molecules pPI3K, pAkt, and pERK, indicating that both signaling pathways are involved in V-ATPase-dependent endosomal acidification. Acidic replenishment of the medium restored uncoating of the RVA strains in cells pretreated with inhibitors specific for both signaling pathways, confirming the above results. Isolated components of the outer capsid proteins, expressed as VP4-VP8* and VP4-VP5* domains, and VP7, activated the PI3K/Akt and MEK/ERK pathways. Furthermore, psoralen-UV-inactivated RVA and CsCl-purified RVA triple-layered particles triggered activation of the PI3K/Akt and MEK/ERK pathways, confirming the above results. Our data demonstrate that multistep binding of outer capsid proteins of L-P RVA strains with cell surface receptors phosphorylates PI3K, Akt, and ERK, which in turn directly interact with the subunit E of the V-ATPase to acidify the late endosome for uncoating of RVAs. This study provides a better understanding of the RVA-host interaction during viral uncoating, which is of importance for the development of strategies aiming at controlling or preventing RVA infections.