Seungyeop Oh, Yeonjung Lim, Meora Rajeev, Jang-Cheon Cho
{"title":"Aliikangiella litoralis sp. nov. and Aliikangiella aequoris sp. nov., isolated from coastal seawaters of the Yellow Sea.","authors":"Seungyeop Oh, Yeonjung Lim, Meora Rajeev, Jang-Cheon Cho","doi":"10.71150/jm.2602008","DOIUrl":"10.71150/jm.2602008","url":null,"abstract":"<p><p>Three Gram-stain-negative, strictly aerobic, motile bacterial strains, designated IMCC44359T, IMCC44632T, and IMCC44653, were isolated from coastal surface seawater collected near Jangbong Island in the Yellow Sea. Phylogenetic analyses based on 16S rRNA gene and whole-genome sequences assigned the isolates to the genus Aliikangiella. Strains IMCC44632T and IMCC44653 shared identical 16S rRNA gene sequences and exhibited high genomic relatedness (99.0% average nucleotide identity and 92.0% digital DNA-DNA hybridization), indicating that they represent a single species. In contrast, strain IMCC44359T showed low genomic relatedness to these strains and to previously validly published Aliikangiella species, supporting its recognition as a distinct species. The genome of IMCC44359T (5.95 Mbp; 36.5 mol% G + C) is substantially larger than those of IMCC44632T and IMCC44653 (~3.75 Mbp; 40.1-40.2 mol% G + C), and all genomes encode aerobic chemoorganotrophic metabolism and biochemical capacities consistent with adaptation to marine environments. The isolates grew under mesophilic and moderately halophilic conditions typical of coastal seawater bacteria, with growth occurring at ranges at 10-40℃, pH 6.0-9.0, and 0.5-7.5% NaCl (optimum, 30℃, pH 7.0-8.0, and 2.0-3.0% NaCl). All strains contained ubiquinone-8 (Q-8) as the sole respiratory quinone, and phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol were the major polar lipids. The dominant cellular fatty acids were iso-C15:0 and summed feature 9 (iso-C17:1 ω9c and/or C16:0 10-methyl). Integrated phylogenetic, genomic, phenotypic evidence supported the recognition of two novel species within the genus Aliikangiella, for which the names Aliikangiella litoralis sp. nov. (type strain IMCC44359T = KCTC 18089T = JCM 37879T = HNIBRBA19635T) and Aliikangiella aequoris sp. nov. (type strain IMCC44632T = KCTC 18090T = JCM 37880T = HNIBRBA19636T) are proposed.</p>","PeriodicalId":16546,"journal":{"name":"Journal of Microbiology","volume":"64 5","pages":"e2602008"},"PeriodicalIF":3.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13576998/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148199011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gracia Pradnya Lolita, Do-Hoon Lee, Yong-Seok Kim, Chang-Jun Cha
{"title":"Paramicrobacterium salitolerans sp. nov. isolated from the agricultural soil and Microbacterium fluminis sp. nov. isolated from the Han River, South Korea.","authors":"Gracia Pradnya Lolita, Do-Hoon Lee, Yong-Seok Kim, Chang-Jun Cha","doi":"10.71150/jm.2512014","DOIUrl":"10.71150/jm.2512014","url":null,"abstract":"<p><p>Two novel bacterial species, designated as CJ85T and CJ88T, were isolated from the agricultural soil and the Han River, South Korea, respectively. Cells of both strains were Gram-staining-positive, short rod-shaped, non-motile, and yellow-pigmented. Strain CJ85T exhibited optimal growth in tryptic soy broth at 37°C and pH 7.0 in the absence of NaCl. Strain CJ88T showed optimal growth in lysogeny broth at 30°C and pH 7.0 in the absence of NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CJ85T belonged to the genus Paramicrobacterium, showing the highest sequence similarity to Paramicrobacterium fandaimingii HY82T (97.6%). Strain CJ88T was assigned to the genus Microbacterium, with the highest sequence similarity to Microbacterium azadirachtae DSM 23848T (98.5%). The DNA G + C content was 64.8% for strain CJ85T and 70.5% for strain CJ88T. The genome-based analyses, including phylogenomic tree, digital DNA-DNA hybridization, and average nucleotide identity, clearly indicated that these strains represent novel species within their respective genera. The major fatty acids of both strains were anteiso-C15:0, anteiso-C17:0, and iso-C16:0. Based on the polyphasic taxonomy study, strains CJ85T and CJ88T represent novel species of the genera Paramicrobacterium and Microbacterium, respectively, for which names Paramicrobacterium salitolerans sp. nov. and Microbacterium fluminis sp. nov. are proposed. The type strains CJ85T (= KACC 23064T = JCM 36217T) and CJ88T (= KACC 24080T = JCM 38050T).</p>","PeriodicalId":16546,"journal":{"name":"Journal of Microbiology","volume":" ","pages":"e2512014"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13577007/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147355602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"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.","authors":"Yeong Jun Kim, Seon Jae Jeong, Hye-Ra Lee","doi":"10.71150/jm.2511014","DOIUrl":"10.71150/jm.2511014","url":null,"abstract":"<p><p>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.</p>","PeriodicalId":16546,"journal":{"name":"Journal of Microbiology","volume":" ","pages":"e2511014"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13577000/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147623251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Synthetic rescue in Saccharomyces cerevisiae: Concepts, large-scale genetic mapping, and functional implications.","authors":"Ji Eun Choi, Woo-Hyun Chung","doi":"10.71150/jm.2512017","DOIUrl":"10.71150/jm.2512017","url":null,"abstract":"<p><p>Synthetic rescue (SR) describes a genetic interaction in which the deleterious effect of a primary mutation is compensated by a second mutation, restoring cellular function or viability. In Saccharomyces cerevisiae, SR complements synthetic lethality (SL) by revealing compensatory mechanisms that maintain essential biological processes. Classical studies established SR as a fundamental principle of genetic robustness in yeast. Subsequent development of high-throughput genetic tools, including Synthetic Genetic Array (SGA), Epistatic Miniarray Profile (E-MAP), and CRISPR interference (CRISPRi), has enabled systematic identification of SR interactions across pathways of genome maintenance, proteostasis, and metabolism. Integration of these experimental datasets with computational and network-based analyses has transformed SR research from descriptive genetics into a predictive framework. Databases such as BioGRID, TheCellMap, and Mslar further support SR inference and link yeast genetic networks to human disease models. Understanding SR has important translational implications. The same compensatory logic that restores viability in yeast can explain therapeutic resistance in cancer cells. Together, these insights reveal SR as a powerful concept connecting microbial genetics with systems medicine, emphasizing that robustness and resilience are dynamic properties of living systems.</p>","PeriodicalId":16546,"journal":{"name":"Journal of Microbiology","volume":" ","pages":"e2512017"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13577003/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147513021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Inhibitory effects of acetyl-11-keto-β-boswellic acid (AKBA) on human cytomegalovirus (HCMV) in vitro.","authors":"Bingquan Chu, Zhiwei Ding, Xinna Wu, Yunchuang Chang, Chunxia Wu, Yicheng Fu, Genxiang Mao, Sanying Wang","doi":"10.71150/jm.2601007","DOIUrl":"10.71150/jm.2601007","url":null,"abstract":"<p><p>This study presents the first investigation of acetyl-11-keto-β-boswellic acid (AKBA)'s anti-human cytomegalovirus (HCMV) activity in vitro and elucidates its underlying mechanisms. In HCMV Towne strain-infected WI-38 cells, AKBA (1-12 μM) exhibited negligible cytotoxicity while significantly suppressing virus-induced cytopathic effects (CPE) at 6-10 μM, with dose-dependent reduction of viral proteins (IE1/2 and p52) expression, viral DNA copy number (UL123, UL44, and UL32), and infectious viral progeny titer (TCID50). Time-of-addition experiments demonstrated the primary antiviral activity of AKBA during post-entry phase, along with direct virion inactivation. Transcriptome analysis revealed that AKBA significantly downregulated the expression of the host factor NR4A1 induced by HCMV, a finding further validated by Western blotting. Further gene knockdown experiments confirmed that silencing NR4A1 significantly reduced the expression of viral proteins IE1/2, thereby validating NR4A1 as a key host factor for HCMV infection. These findings indicate that AKBA has a potent and dose-dependent inhibitory effect on HCMV replication in WI-38 cells, and proves that this effect is mediated through two different mechanisms: one is the downregulation of the expression of the key host factor NR4A1, and the other is the direct inactivation of HCMV viral particles.</p>","PeriodicalId":16546,"journal":{"name":"Journal of Microbiology","volume":" ","pages":"e2601007"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13577096/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147513039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kiran Kirdat, Malad Mubarak, Pradeep Choudhary, Shivaji Sathe, Amit Yadav
{"title":"Genomic landscape reveals the dominance of self-catalytic, high-copy group II introns in PMU-deficient complete genomes of PWB phytoplasmas.","authors":"Kiran Kirdat, Malad Mubarak, Pradeep Choudhary, Shivaji Sathe, Amit Yadav","doi":"10.71150/jm.2511004","DOIUrl":"10.71150/jm.2511004","url":null,"abstract":"<p><p>Phytoplasmas are wall-less obligate parasites of plants and insects. Several phytoplasma strains within the Peanut Witches' Broom (PWB; 16SrII) group are associated with significant disease losses across diverse crops and weeds. We present complete, single contig genome assemblies for two Indian parthenium phyllody strains, 'Candidatus Phytoplasma asiaticum' PR34 and 'Ca. P. australasiaticum' PR08, generated through host DNA depletion and hybrid Illumina-Nanopore sequencing. Both genomes display characteristic features of reductive evolution (∼614 kb and 589 kb, respectively) but show notable differences from previously sequenced PWB phytoplasmas. In contrast to most of PMU-rich phytoplasma genomes, neither PR34 nor PR08 retains intact Potential Mobile Units. Instead, both harbor numerous open reading frames encoding group II intron reverse transcriptase/ maturase proteins, predominantly of the mitochondrial-like type, with PR34 containing 52 and PR08 28 such loci that together constitute > 4% of each genome. These observations support the hypothesis that intron-associated processes may contribute to genome variability in the absence of canonical PMUs. Comparative analyses support the classification of PR34 as a distinct species within the PWB complex and reveal both conserved Sec-dependent effectors (SAP05, SAP11, and SAP54/PHYL1) and lineage-specific secreted proteins with predicted nuclear localization. Additional retained features include functional sodA genes and multiple truncated HlyB-like transporters. Collectively, these high-quality genomes illustrate a genomic configuration in which extensive genome reduction and loss of PMUs coexist with the retention of core virulence factors and an expanded repertoire of group II introns, providing a framework for future investigation of genome plasticity in phytoplasmas.</p>","PeriodicalId":16546,"journal":{"name":"Journal of Microbiology","volume":" ","pages":"e2511004"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13577128/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147513009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Antimicrobial effects and mechanism of action of carboxymethyl chitosan-loaded silver ion complexes against drug-resistant Aspergillus fumigatus.","authors":"Lingsheng Jin, Xinyu Zhou, Wenlong Du","doi":"10.71150/jm.2512001","DOIUrl":"10.71150/jm.2512001","url":null,"abstract":"<p><p>Based on the escalating challenge of drug-resistant Aspergillus fumigatus infections, this study developed a silver ion-loaded carboxymethyl chitosan (CMCh-Ag⁺) nanocomposite as a potent antifungal agent. The composite was successfully synthesized and characterized, revealing distinct physicochemical properties, uniform dispersion, and confirmed coordination between CMCh and Ag⁺. In vitro evaluations, including minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), growth curve, and plate spotting assays, demonstrated that CMCh-Ag⁺ exhibited significantly superior antifungal efficacy against multiple A. fumigatus strains (including azole-resistant isolates) compared to CMCh or Ag⁺ alone. In vivo experiments using a Galleria mellonella infection model confirmed the enhanced therapeutic effect and biocompatibility of CMCh-Ag⁺. Investigations into the mechanism-related phenotypes revealed that CMCh-Ag⁺ significantly removed fungal biofilm and was associated with a substantial accumulation of intracellular reactive oxygen species (ROS), correlating with fungal cell death. This research highlights the preliminary potential of CMCh Ag⁺ as a candidate strategy to combat drug-resistant A. fumigatus infections, warranting further investigation in mammalian models to assess its clinical translational prospects.</p>","PeriodicalId":16546,"journal":{"name":"Journal of Microbiology","volume":" ","pages":"e2512001"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13577134/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147623159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Structural perspectives on clinical β-lactamase inhibitors: From mechanism to resistance.","authors":"Soo-Bong Park, Myeong-Yeon Kim, Sun-Shin Cha","doi":"10.71150/jm.2510019","DOIUrl":"10.71150/jm.2510019","url":null,"abstract":"<p><p>β-Lactam antibiotics marked the beginning of an era of effective and safe treatment for bacterial infections and remain the most widely prescribed antibacterial agents today. However, the emergence of antibiotic-resistant bacteria threatens a return to the pre-antibiotic era. In particular, bacterial expression of β-lactamases inactivating β-lactam antibiotics presents a challenge in antimicrobial therapy. While inhibitors against β-lactamases have been developed to protect the therapeutic efficacy of β-lactam antibiotics, the clinical use of β-lactamase inhibitors is constrained due to their limited inhibition spectrum and the emergence of inhibitor-resistant β-lactamase variants. As an effort to tackle this issue, here we reviewed the structural and mechanistic features of β-lactamases and their FDA-approved inhibitors. Moreover, mutations in clinically isolated β-lactamases that confer resistance against their inhibitors are compiled. The comprehensive overview offered in this review aims to support and stimulate the design of next-generation β-lactamase inhibitors for combating β-lactamase-mediated antibiotic resistance.</p>","PeriodicalId":16546,"journal":{"name":"Journal of Microbiology","volume":" ","pages":"e2510019"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13577047/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147513014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The rise and future of peptide-based antimicrobials.","authors":"Hyo Jung Kim","doi":"10.71150/jm.2510002","DOIUrl":"10.71150/jm.2510002","url":null,"abstract":"<p><p>The escalating threat of antimicrobial resistance has renewed global interest in peptide-based antibiotics as adaptable and effective alternatives to conventional small molecules. Peptides possess diverse mechanisms of action, high target specificity, and structural flexibility, which collectively limit the emergence of resistance. This review outlines recent advances spanning the discovery, optimization, and application of peptide antibiotics, from their biological origins and structural classifications to emerging strategies involving artificial intelligence, synthetic biology, and modern delivery technologies. Peptide antibiotics can be categorized by origin as natural, semi-synthetic, or fully synthetic, and further organized by structural class such as α-helical, β-sheet, cyclic, and extended forms. They are also grouped by function into membrane-targeted and non-membrane-targeted types. These classification schemes are not only descriptive but also critical for understanding the therapeutic potential of peptides, as each category presents distinct advantages and engineering challenges that influence stability, specificity, and overall clinical performance. Advances in artificial intelligence, synthetic biology, and continuous manufacturing are reshaping how peptide drugs are designed and produced, while innovations in drug delivery systems are addressing critical issues of stability and bioavailability. Together, these developments are laying the foundation for a new generation of peptide-based therapeutics capable of meeting the evolving challenges of antimicrobial resistance.</p>","PeriodicalId":16546,"journal":{"name":"Journal of Microbiology","volume":" ","pages":"e2510002"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13577038/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147283799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}