Yeon-Ju Kim

Gastric cancer has high morbidity and mortality rates worldwide, often requiring new therapeutic approaches. Biosynthesis of gold nanoparticles (GNPs) offers a promising treatment due to their unique biological properties and biocompatibility. In this study, we synthesized gold nanoparticles using the cultural supernatant of Microbacterium sp. MAH-37 (MM37-S) and evaluated their anti-gastric cancer activity, focusing on apoptosis induction and regulation of the ABCG transporter pathway. The Microbacterium sp. strain MAH-37 was isolated from pumpkin garden soil, and its morphology was characterized by transmission electron microscopy (TEM). The successful biosynthesis of MM37-S-GNP was confirmed by UV–visible spectroscopy, SAED, DLS, FTIR, XRD, EDX, and FE-TEM analyses. Biological evaluations revealed that MM37-S-GNPs exhibited cytotoxicity of approximately 72% at 200 µg/mL against AGS cells and confirmed by colony formation and Live/Dead assay, whereas normal HFE-145 cells was non-toxic. Furthermore, Hoechst 33,258, propidium iodide, and Mito Tracker revealed nuclear condensation and fragmentation, membrane-compromised cells, and mitochondrial disruption, respectively, indicating cell death via apoptosis. H₂DCFDA staining demonstrated a significant increase intracellular reactive oxygen species (ROS) generation in AGS cells following MM37-S-GNP. Flow cytometric analysis revealed that treatment induced apoptosis in AGS cells, with 30.4% apoptotic cells observed at 200 µg/mL. Consistently, mRNA and protein expression levels confirmed apoptosis cell death, as evidenced by an increased Bax/Bcl-2 ratio and elevated levels of cleaved caspase-9. Additionally, Western blot analysis revealed that treatment with higher doses of MM37-S-GNPs significantly downregulated the expression of ABCG1 and ABCG2 transporters. MM37-S-GNPs selectivelyeliminated gastric cancer cells through ROS-mediated mitochondrial damage and apoptotic pathways, while effectively regulating ABCG transporter expression, highlighting their potential as a promising nanotherapeutic agent. Graphical Abstract

Since the first reported HIV case in Korea in 1985, the incidence of HIV/AIDS has continued to rise, emphasizing the need for effective prevention and management strategies. While global initiatives aim to end the epidemic by 2030, Korea has observed demographic shifts, particularly among young men and foreign nationals, that warrant further investigation. We analyzed national HIV incidence data from 1985 to 2024, stratified by nationality, age, transmission route, and testing motivation. To forecast future trends, we employed a stacking ensemble model combining ARIMA, Random Forest, and LSTM, each trained to capture different aspects of temporal and demographic patterns. Model performance was evaluated using RMSE and MAE. Annual new HIV infections rose steadily until the mid-2010s, peaking at 1,223 cases in 2019, before stabilizing around 975–1,000 cases by 2024. Korean men showed a recent decline, while foreign nationals, especially foreign women, displayed continuous growth. Young men aged 25–34 emerged as the most affected group, comprising nearly half of male cases in 2023. The ensemble model outperformed individual approaches, projecting that new HIV cases will stabilize at approximately 1,024 annually through 2030. Analysis of HIV incidence in Korea using 40-year trend data reveals a historically rising trend that has recently begun to stabilize, with projections suggesting this plateau will continue through 2030. Ensemble-based forecasting models leveraging four decades of surveillance data may enhance predictive accuracy and serve as a framework for other settings facing shifts in HIV epidemiology.

COVID-19, an unprecedented global pandemic, has caused successive waves that pose unique challenges to public health and epidemiological research. Traditional Susceptible–Infected–Recovered (SIR) models often struggle to capture these complex dynamics, especially given that the virus has spawned multiple sub-variants. To tackle these challenges, we adopt an empirical modeling approach by integrating real-world data from Our World in Data (daily confirmed COVID-19 cases) and GISAID (variant prevalence) into a newly proposed integrated model. Specifically, we sum multiple sigmoidal (logistic) curves, each representing the cumulative infections of a distinct dominant variant, and recalibrate the model whenever a new variant emerges. By incorporating variant-specific parameters, our framework effectively captures the biological and epidemiological characteristics of COVID-19 in a dynamic, data-driven manner. Most importantly, we employ the Pruned Exact Linear Time (PELT) algorithm to provide rigorous mathematical justification for when separate variant models can be legitimately summed: specifically, when variant dominance reaches approximately 50%. This establishes the theoretical foundation that separate logistic models can be additively combined under specific dominance conditions. We evaluate our model using Mean Absolute Percentage Error (MAPE), Root Mean Square Error (RMSE), and Mean Absolute Error (MAE). Our empirical findings confirm that integrating dominant variants is associated with markedly improved accuracy compared to a single-strain approach, based on data from fourteen countries (including South Korea, the United States, and the United Kingdom) and global aggregates. We also provide theoretical motivation for approximating SIR dynamics via logistic functions and discuss how this integrated framework can be refined to enhance predictive performance. In doing so, we demonstrate the feasibility and advantages of iteratively updating epidemiological models in response to emerging variants, thereby offering actionable insights for ongoing and future pandemic management.

High‐fat, high‐sucrose (HFHS) diet consumption is a major contributor to obesity and liver‐related metabolic disorders. Momordica charantia ethanolic extract powder (MC), derived from a traditional climbing plant, has been shown to exert multiple biological activities, including exhibiting antidiabetic, antioxidant, and antiinflammatory activities. Building on these properties, the present study investigated the potential effects of MC on hepatic lipid metabolism and obesity‐related parameters in mice fed a HFHS diet. Male C57BL/6J mice (6 weeks old) were fed an HFHS diet for 4 weeks and subsequently divided into four dietary groups, receiving either continued HFHS, Cissus quadrangularis (CQ; positive control), MC 125 (125 mg/kg), or MC 250 (250 mg/kg) for an additional 12 weeks. Compared with the HFHS group, MC supplementation was associated with lower body weight gain, hepatic lipid accumulation, and epididymal adipocyte size. Histological findings were consistent with these changes in adipose tissue. At the molecular level, MC supplementation was associated with altered hepatic expression of genes involved in lipid metabolism, including decreased expression of the lipogenesis‐related genes SREBP-1c , ACC , FAS , and SCD1 , as well as alterations in C/EBPα and PPARγ expression. In addition, the expression of fibrosis‐related genes Col1α1 and αSMA was decreased in the MC‐supplemented groups. These findings suggest that MC supplementation may modulate hepatic lipid metabolism‐ and fibrosis‐related gene expression in HFHS diet‐fed mice. Collectively, the present findings suggest that MC may influence metabolic responses associated with chronic consumption of a HFHS diet.

Protaetia brevitarsis seulensis (white-spotted flower chafer) larvae are rich in amino acids and fatty acids, making them an environmentally sustainable and promising alternative protein source. Fermentation is recognised as an effective approach to enhance nutrient availability and influence the nutritional profile of biological materials. This study aimed to investigate whether fermenting P. brevitarsis larvae with Bacillus subtilis PB2441 prior to extraction could improve their nutritional composition and immunomodulatory effects. The larvae were either extracted using papain alone (PE) or fermented with B. subtilis PB2441 after papain treatment (PEP). The fermented extract (PEP) exhibited significantly higher levels of amino acids and fatty acids, resulting in an improved nutritional profile. In addition, PEP showed stronger antioxidant activity, enhanced nitric oxide (NO) production, upregulated immune-related biomarker expression, and increased both splenocyte proliferation and natural killer (NK) cell cytotoxicity compared to the non-fermented extract. Neither extract exhibited cytotoxic effects. These results indicate that fermentation-assisted extraction can effectively enhance the nutritional value and immunological functionality of P. brevitarsis larvae. Furthermore, this study supports the use of fermentation as a means to improve the nutritional potential of edible insects, reinforcing their applicability as sustainable ingredients in the food and feed sectors.

Studies on the impact of gram-positive extracellular vesicles have paved the way for novel medical advancements. These vesicles serve as efficient carriers of microbial molecules to target cells, thereby influencing human pathophysiological processes. Thus, this study aimed to investigate the anti-inflammatory properties of extracellular vesicles derived from Lactobacillus gasseri GFC-1220 (LEVs) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. LEVs were characterized using transmission electron microscopy, nanoparticle tracking analysis, and dynamic light scattering measurements to examine their morphology, size, and concentration. We further assessed the anti-inflammatory effects of LEVs and their underlying mechanism in LPS-stimulated RAW264.7 macrophages. Our findings revealed that LEVs did not cause cytotoxic effects and significantly decreased the level of mitochondria superoxide and reactive oxygen species production. In addition, these vesicles effectively inhibited the LPS-induced activation of TLR4/NF-κB signaling pathway, consequently suppressing the secretion and expression of various pro-inflammatory mediators and cytokines. These included a reduction in the production of NO and PGE₂, along with their corresponding producer enzymes iNOS and COX-2, as well as IL-6, TNF-α, and IL-1β cytokines. These findings strongly suggest that LEVs have significant potential for the development of new anti-inflammatory agents.