Publications by authors named "Ji-Yeon Hwang"

Specialized or secondary metabolites are small molecules of biological origin, often showing potent biological activities with applications in agriculture, engineering and medicine. Usually, the biosynthesis of these natural products is governed by sets of co-regulated and physically clustered genes known as biosynthetic gene clusters (BGCs). To share information about BGCs in a standardized and machine-readable way, the Minimum Information about a Biosynthetic Gene cluster (MIBiG) data standard and repository was initiated in 2015.

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Ethnopharmacological Relevance: Traditional herbal medicine books "Shin Rhong Bon Cho Kyung" and "Hyang Yak Jip Sung Bang" mentioned that Bletilla striata (Thunb.) Rchb.f.

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Article Synopsis
  • Four tunicamycin compounds were identified from a marine actinomycete strain, revealing their potential as antibacterial agents.
  • The compounds demonstrated strong activity against Gram-positive bacteria, with minimum inhibitory concentration (MIC) values between 0.13-0.25 µg/mL.
  • They were found to inhibit the MraY enzyme, crucial for bacterial cell wall synthesis, with inhibitory concentrations (IC) ranging from 0.08-0.21 µg/mL.
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  • Intranasal infection is a common method to study SARS-CoV-2 in mice, but it often results in high mortality rates, limiting research on non-fatal COVID-19 cases.
  • Substituting intranasal administration with aerosolized inhalation shows unique and milder pathological features that align better with COVID-19 symptoms seen in patients, such as chest CT patterns.
  • The research indicates that the inhalation model allows for the study of long COVID and related interventions by mimicking non-fatal COVID-19 conditions more effectively than the intranasal method.
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Viral load and the duration of viral shedding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are important determinants of the transmission of coronavirus disease 2019. In this study, we examined the effects of viral doses on the lung and spleen of K18-hACE2 transgenic mice by temporal histological and transcriptional analyses. Approximately, 1×10 plaque-forming units (PFU) of SARS-CoV-2 induced strong host responses in the lungs from 2 days post inoculation (dpi) which did not recover until the mice died, whereas responses to the virus were obvious at 5 days, recovering to the basal state by 14 dpi at 1×10 PFU.

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Background: The global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to approximately 500 million cases and 6 million deaths worldwide. Previous investigations into the pathophysiology of SARS-CoV-2 primarily focused on peripheral blood mononuclear cells from patients, lacking detailed mechanistic insights into the virus's impact on inflamed tissue. Existing animal models, such as hamster and ferret, do not faithfully replicate the severe SARS-CoV-2 infection seen in patients, underscoring the need for more relevant animal system-based research.

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Translational regulation in tissue environments during in vivo viral pathogenesis has rarely been studied due to the lack of translatomes from virus-infected tissues, although a series of translatome studies using in vitro cultured cells with viral infection have been reported. In this study, we exploited tissue-optimized ribosome profiling (Ribo-seq) and severe-COVID-19 model mice to establish the first temporal translation profiles of virus and host genes in the lungs during SARS-CoV-2 pathogenesis. Our datasets revealed not only previously unknown targets of translation regulation in infected tissues but also hitherto unreported molecular signatures that contribute to tissue pathology after SARS-CoV-2 infection.

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Nuclear factor kappa B (NF-κB) signaling pathways progress inflammation and immune cell differentiation in the host immune response; however, the uncontrollable stimulation of NF-κB signaling is responsible for several inflammatory illnesses regardless of whether the conditions are acute or chronic. Innate immune cells, such as macrophages, microglia, and Kupffer cells, secrete pro-inflammatory cytokines, such as TNF-α, IL-6, and IL-1β, via the activation of NF-κB subunits, which may lead to the damage of normal cells, including neurons, cardiomyocytes, hepatocytes, and alveolar cells. This results in the occurrence of neurodegenerative disorders, cardiac infarction, or liver injury, which may eventually lead to systemic inflammation or cancer.

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Article Synopsis
  • COVID-19 severity ranges from mild to fatal, linked to immune system dysfunction, specifically lymphoid depletion and low lymphocyte counts.
  • Research using hACE2 transgenic mice showed that severe COVID-19 leads to significant lymphoid tissue depletion and impaired antigen-presenting cell (APC) function, correlating with increased mortality.
  • Findings indicate that these immune changes are unique to SARS-CoV-2 and suggest that improving APC functionality could be a potential treatment strategy for severe COVID-19 cases.
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Muscle atrophy, also known as muscle wasting, is the thinning of muscle mass due to muscle disuse, aging, or diseases such as cancer or neurological problems. Muscle atrophy is closely related to the quality of life and has high morbidity and mortality. However, therapeutic options for muscle atrophy are limited, so studies to develop therapeutic agents for muscle loss are always required.

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Throughout the recent COVID-19 pandemic, South Korea led national efforts to develop vaccines and therapeutics for SARS-CoV-2. The project proceeded as follows: 1) evaluation system setup (including Animal Biosafety Level 3 (ABSL3) facility alliance, standardized nonclinical evaluation protocol, and laboratory information management system), 2) application (including committee review and selection), and 3) evaluation (including expert judgment and reporting). After receiving 101 applications, the selection committee reviewed pharmacokinetics, toxicity, and efficacy data and selected 32 final candidates.

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing coronavirus disease 2019 (COVID-19) has been a global health concern since 2019. The viral spike protein infects the host by binding to angiotensin-converting enzyme 2 (ACE2) expressed on the cell surface, which is then processed by type II transmembrane serine protease. However, ACE2 does not react to SARS-CoV-2 in inbred wild-type mice, which poses a challenge for preclinical research with animal models, necessitating a human ACE2 (hACE2)-expressing transgenic mouse model.

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Article Synopsis
  • SARS-CoV-2 is a highly contagious virus that can cause severe illness, affecting primarily the lungs and spleen, as shown in infected K18-hACE2 mice modeling human symptoms.
  • After 7 days of infection, the mice exhibited significantly impaired vital signs leading to death, with evidence of bronchopneumonia and changes in immune responses in the lungs and spleen.
  • Transcriptomic analysis revealed a complex immune response over time, with the spleen showing a quicker defense mechanism and distinct cellular responses based on their ability to either manage the virus or struggle with recovery, providing insights for potential treatments for COVID-19.
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Hypertrophic osteoarthropathy (HOA) is a syndrome characterized by digital clubbing, periosteal bone formation, and synovial effusions. Secondary HOA is associated with intrathoracic malignancy in most cases; however, in rare cases, HOA can be caused by extrathoracic conditions. We report early ultrasound, computed tomography, magnetic resonance imaging, and bone scintigraphy findings of HOA in a patient with breast cancer.

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  • SARS-CoV-2 is the virus responsible for COVID-19, leading to serious respiratory disease and complications in humans.
  • Researchers used K18-hACE2 mice and Syrian golden hamsters to study how the virus impacts hosts, focusing on symptoms, disease progression, and immune responses.
  • The study found that while K18-hACE2 mice experienced severe and fatal disease, Syrian golden hamsters had milder, reversible symptoms with no fatalities, highlighting differences in how these models react to the virus.
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Background: As the number of large-scale studies involving multiple organizations producing data has steadily increased, an integrated system for a common interoperable format is needed. In response to the coronavirus disease 2019 (COVID-19) pandemic, a number of global efforts are underway to develop vaccines and therapeutics. We are therefore observing an explosion in the proliferation of COVID-19 data, and interoperability is highly requested in multiple institutions participating simultaneously in COVID-19 pandemic research.

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Background: , an important Gram-positive pathogen in dental caries, uses sortase A (SrtA) to anchor surface proteins to the bacterial cell wall, thereby promoting biofilm formation and attachment to the tooth surface.

Design: Based on activity-guided separation, inhibitors of SrtA were isolated from and identified through combined spectroscopic analysis. Further effects of isolated SrtA inhibitor on were evaluated on bacterial aggregation, adherence and biofilm formation.

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Two nitrogenous metabolites, bacillimide () and bacillapyrrole (), were isolated from the culture broth of the marine-derived actinomycete . Based on the results of combined spectroscopic and chemical analyses, the structure of bacillimide () was determined to be a new cyclopenta[]pyrrole-1,3-dione bearing a methylsulfide group, while the previously reported bacillapyrrole () was fully characterized for the first time as a pyrrole-carboxamide bearing an alkyl sulfoxide side chain. Bacillimide () and bacillapyrrole () exerted moderate (IC = 44.

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The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants that escape vaccine-induced neutralizing antibodies has indicated the importance of T cell responses against this virus. In this study, we highlight the SARS-CoV-2 epitopes that induce potent T cell responses and discuss whether T cell responses alone are adequate to confer protection against SARS-CoV-2 and describe the administration of 20 peptides with an RNA adjuvant in mice. The peptides have been synthesized based on SARS-CoV-2 spike and nucleocapsid protein sequences.

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In mammals, environmental cold sensing conducted by peripheral cold thermoreceptor neurons mostly depends on TRPM8, an ion channel that has evolved to become the main molecular cold transducer. This TRP channel is activated by cold, cooling compounds, such as menthol, voltage, and rises in osmolality. TRPM8 function is regulated by kinase activity that phosphorylates the channel under resting conditions.

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Ochraceopetalin (), a mixed-biogenetic salt compound and its component were isolated from the culture broths of a marine-derived fungus, . Based on combined spectroscopic and chemical analyses, the structure of was determined to be a sulfonated diphenylether-aminol-amino acid ester guanidinium salt of an unprecedented structural class, while was determined to be the corresponding sulfonated diphenylether. Ochraceopetaguanidine (), the other guanidine-bearing aminol amino acid ester component, was also prepared and structurally elucidated.

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Four epipolythiodioxopiperazine fungal metabolites (-) isolated from the sponge-derived FJJ093 were evaluated for their capacity to inhibit isocitrate lyase (ICL) in the glyoxylate cycle of . The structures of these compounds were elucidated using spectroscopic techniques and comparisons with previously reported data. We found secoemestrin C () (an epitetrathiodioxopiperazine derivative) to be a potent ICL inhibitor, with an inhibitory concentration of 4.

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