Journal of Microbiology

Articles

Functional characterization of spike RBD mutations in SARS-CoV-2 Omicron-derived subvariants KP.3.1.1, LP.8.1, and NB.1.8.1.: Yeong Jun Kim, Seon Jae Jeong, Hye-Ra Lee; Received November 17, 2025 Accepted January 14, 2026 Published online April 6, 2026; DOI: https://doi.org/10.71150/jm.2511014 [Epub ahead of print]

164 View
11 Download

Abstract PDF: Following the global spread of SARS-CoV-2 Omicron (B.1.1.529), its subvariants KP.3.1.1, LP.8.1, and NB.1.8.1 disseminated worldwide. By April 2025, the epidemiological landscape of these subvariants had become distinct, with LP.8.1 emerging as the predominant variant, KP.3.1.1 persisting as a co-circulating variant under monitoring (VUM), and NB.1.8.1 exhibiting a significant increase in prevalence. Despite their epidemiological prominence, the functional consequences of spike mutations defining these emerging subvariants remain poorly understood. Here, we systematically dissected the entry properties conferred by their receptor-binding domain (RBD) mutations using a pseudovirus system. Our results demonstrate that all three subvariants exhibited substantially higher infectivity than ancestral Omicron. Unexpectedly, this enhanced infectivity occurred despite reduced ACE2 binding affinity. Rather, increased viral entry consistently correlated with elevated spike cleavage efficiency and fusogenicity, suggesting a compensatory evolutionary strategy in which enhanced spike processing and fusion contribute to enhanced entry despite reduced receptor engagement. These findings provide a virological explanation for the accelerated global spread of these subvariants and highlight the importance of monitoring functional shifts in spike-mediated entry that may influence SARS-CoV-2 transmission dynamics.

Development of tri-cistronic CLDN18.2 CAR-T cells incorporating PD-1/CD28 switch and cyclophilin A for enhanced solid tumor immunotherapy: Heon Ju Lee, Seo Jin Hwang, Eun Hee Jeong, Mi Hee Chang, Bu Yeon Heo, Jaeyul Kwon, Yoona Noh, Jihoon Nah; J. Microbiol. 2026;64(1):e2510017. Published online January 31, 2026; DOI: https://doi.org/10.71150/jm.2510017

1,451 View
47 Download

Abstract PDF Supplementary Material: Chimeric antigen receptor (CAR)-T cell therapy holds significant potential for the treatment of solid tumors. However, immune suppression and tumor-specific barriers limit its application. Claudin 18.2 (CLDN18.2), a gastric lineage-specific tight junction protein highly expressed in gastric and pancreatic cancers, is a promising therapeutic target. In this study, we aimed to develop a next-generation tri-cistronic CLDN18.2-directed CAR-T cell platform that integrates a programmed cell death protein 1 (PD-1)/CD28 chimeric switch receptor with cyclophilin A (CypA). This platform sought to counteract PD-1–mediated immunosuppression and enhance T-cell activation and persistence. We generated CLDN18.2 CAR-T cells incorporating costimulatory inducible T-cell costimulator (ICOS) domains using lentiviral vector-based recombinant engineering. We further evaluated their cytokine release, cytotoxic activity, and safety profiles. In vitro, tri-cistronic CAR-T cells exhibited markedly increased interferon γ and tumor necrosis factor α secretion and enhanced cytotoxicity against CLDN18.2-positive gastric cancer cells compared with conventional CAR-T constructs. In vivo, these cells showed superior antitumor efficacy and sustained tumor regression without observable toxicity in xenograft gastric cancer models. Collectively, these findings demonstrate that the integration of PD-1/CD28 signaling and CypA within a tri-cistronic framework significantly reinforces CAR-T cell functionality and durability. This suggests strong clinical potential as a next-generation immunotherapy for solid tumors.

Characterization of novel bacteriophages for effective phage therapy against Vibrio infections in aquaculture: Kira Moon, Sangdon Ryu, Seung Hui Song, Se Won Chun, Nakyeong Lee, Aslan Hwanhwi Lee; J. Microbiol. 2025;63(5):e2502009. Published online May 27, 2025; DOI: https://doi.org/10.71150/jm.2502009

7,166 View
247 Download
3 Web of Science
3 Crossref

Abstract PDF Supplementary Material

The widespread use of antibiotics in aquaculture has led to the emergence of multidrug-resistant pathogens and environmental concerns, highlighting the need for sustainable, eco-friendly alternatives. In this study, we isolated and characterized three novel bacteriophages from aquaculture effluents in Korean shrimp farms that target the key Vibrio pathogens, Vibrio harveyi, and Vibrio parahaemolyticus. Bacteriophages were isolated through environmental enrichment and serial purification using double-layer agar assays. Transmission electron microscopy revealed that the phages infecting V. harveyi, designated as vB_VhaS-MS01 and vB_VhaS-MS03, exhibited typical Siphoviridae morphology with long contractile tails and icosahedral heads, whereas the phage isolated from V. parahaemolyticus (vB_VpaP-MS02) displayed Podoviridae characteristics with an icosahedral head and short tail.

Whole-genome sequencing produced complete, circularized genomes of 81,710 bp for vB_VhaS-MS01, 81,874 bp for vB_VhaS-MS03, and 76,865 bp for vB_VpaP-MS02, each showing a modular genome organization typical of Caudoviricetes. Genomic and phylogenetic analyses based on the terminase large subunit gene revealed that although vB_VhaS-MS01 and vB_VhaS-MS03 were closely related, vB_VpaP-MS02 exhibited a distinct genomic architecture that reflects its unique morphology and host specificity. Collectively, these comparative analyses demonstrated that all three phages possess genetic sequences markedly different from those of previously reported bacteriophages, thereby establishing their novelty. One-step growth and multiplicity of infection (MOI) experiments demonstrated significant differences in replication kinetics, such as burst size and lytic efficiency, among the phages, with vB_VhaS-MS03 maintaining the most effective bacterial control, even at an MOI of 0.01. Additionally, host range assays showed that vB_VhaS-MS03 possessed a broader spectrum of activity, supporting its potential use as a stand-alone agent or key component of phage cocktails. These findings highlight the potential of region-specific phage therapy as a targeted and sustainable alternative to antibiotics for controlling Vibrio infections in aquaculture.

Citations

Citations to this article as recorded by

Revolutionizing seafood safety with bacteriophages: emerging technologies and applications
Nigar Sultana Meghla, Soo-Jin Jung, Md Furkanur Rahaman Mizan, Syeda Roufun Nesa, IkSoon Kang, Sang-Do Ha
Food Microbiology.2026; 137: 105021. CrossRef
Genomic characterization of APEC phages and evaluation of the efficacy in reducing the loads of APEC O78 infections in chickens
Qin Lu, Xinxin Jin, Zui Wang, Rongrong Zhang, Yunqing Guo, Qiao Hu, Wenting Zhang, Tengfei Zhang, Qingping Luo
Frontiers in Microbiology.2026;[Epub] CrossRef
Feed Additives in Aquaculture: Benefits, Risks, and the Need for Robust Regulatory Frameworks
Ekemini Okon, Matthew Iyobhebhe, Paul Olatunji, Mary Adeleke, Nelson Matekwe, Reuben Okocha
Fishes.2025; 10(9): 471. CrossRef

Comparative Secretory Efficiency of Two Chitosanase Signal Peptides from Bacillus subtilis in Escherichia coli: Tae-Yang Eom, Yehui Gang, Youngdeuk Lee, Yoon-Hyeok Kang, Eunyoung Jo, Svini Dileepa Marasinghe, Heung Sik Park, Gun-Hoo Park, Chulhong Oh; J. Microbiol. 2024;62(12):1155-1164. Published online November 25, 2024; DOI: https://doi.org/10.1007/s12275-024-00186-1

612 View
9 Download
2 Web of Science
3 Crossref

Search