Cyclic adenosine monophosphate (cAMP) signaling is a major regulatory system in mycobacteria, and the cAMP receptor protein (CRP) serves as its principal transcriptional effector. In Mycobacterium tuberculosis, CRP controls a broad regulon associated with metabolic adaptation, respiration, cell envelope-associated processes, dormancy-related resuscitation, and virulence. Structural and biophysical studies have demonstrated that mycobacterial CRPs differ from the classical Escherichia coli paradigm: apo-CRP adopts restrained or asymmetric conformations, whereas cAMP binding promotes a more symmetric, DNA-binding-competent state and enhances the specificity of CRP-DNA interactions. In Mycobacterium smegmatis, the major paralog Crp1 (MSMEG_6189) regulates metabolic and respiratory adaptation, oxidative stress defense, and isoniazid susceptibility, whereas Crp2 (MSMEG_0539) appears to play a more limited or subsidiary role. Recent findings further reveal that CRP activity is modulated by lysine acetylation, cooperative promoter recruitment with the virulence-associated response regulator PhoP, and respiratory inhibition-induced increases in intracellular cAMP, thereby linking metabolic and respiratory status to adaptive and virulence-associated gene regulation. This review summarizes the structure, allosteric regulation, regulon, and physiological functions of mycobacterial CRPs, highlighting their role as central integrators of cAMP signaling, respiratory and metabolic state, persistence-associated physiology, and antibiotic susceptibility.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick‑borne zoonosis in East Asia, yet the contribution of animals to virus maintenance and spillover remains incompletely characterized. This review examines current evidence of SFTS virus (SFTSV) infection across domestic livestock, companion animals, wildlife, and captive species, focusing on host range, geographic distribution, diagnostics, and reports of viral RNA and virus isolation. Available data indicate that SFTSV exposure and infection occur across a broad range of animal hosts, supporting a multi-host ecological framework rather than a simple single-reservoir interpretation. Domestic ruminants frequently exhibit high seroprevalence and may function as sentinels of enzootic activity, while occasional virus isolation from cattle demonstrates that viable virus can be recovered from naturally infected livestock, although this does not establish reservoir or amplification competence. Companion animals are considered a potential interface for interspecies transmission, as some studies have documented severe clinical disease, high viral loads, and cat-associated human transmission events supported by varying levels of epidemiological and genomic evidence. Studies in wildlife further document exposure and natural infection across diverse taxa, although their specific roles in viral maintenance remain unresolved. Interpretation of these findings depends heavily on the diagnostic modality: serology primarily indicates prior exposure, RNA detection supports current or recent infection, and virus isolation demonstrates that viable virus was present in the sampled material. Integrating animal infection data within an ecological framework reveals major knowledge gaps related to reservoir competence, infectious shedding, phylogenetic connections among animal, tick, and human cases, and implications for prevention. The review underscores the need for One Health surveillance that incorporates clinical data from companion animals and applies evidence‑based interpretation to improve recognition of animal–human interfaces associated with potential spillover risk.

Three bacterial strains, W99^T, S113^T, and S268^T, were isolated from marine algae and subjected to polyphasic taxonomic characterization. Phylogenetic and phylogenomic analyses placed W99^T within the genus Shimia, whereas S113^T and S268^T formed two distinct genus-level lineages within the family Roseobacteraceae. The three isolates were Gram-stain-negative, non-motile, and obligately aerobic, with optimum growth at 25, 25, and 30°C, respectively, and at 2.0% (w/v) NaCl. Ubiquinone-10 was the sole respiratory quinone in all three strains. The major fatty acids were 11-methyl C_18:1 ω7c and summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c) in strain W99^T; C_16:0 and summed feature 8 in strain S113^T; and 11-methyl C_18:1 ω7c, cyclo-C_19:0 ω8c, and summed feature 8 in strain S268^T. The major polar lipids were phosphatidylglycerol and phosphatidylcholine, with diphosphatidylglycerol additionally detected in strain S268^T. Polyphasic taxonomic analyses demonstrated that strain W99^T represents a novel species of the genus Shimia, for which the name Shimia rhodophyticola sp. nov. is proposed (W99^T = KACC 24154^T = JCM 38196^T), whereas strains S113^T and S268^T represent two novel genera and species, Neomarinovum algicola gen. nov., sp. nov. (S113^T = KACC 23417^T = JCM 38210^T) and Phycorhabdus gracilariae gen. nov., sp. nov. (S268^T = KACC 24156^T = JCM 38211^T), respectively. In addition, comprehensive phylogenomic and genome-based relatedness analyses support the taxonomic revision of nineteen taxa within the family Roseobacteraceae, providing a revised genome-based taxonomic framework that better reflects the evolutionary relationships within the family.

Two novel bacterial strains, designated HNIBRBA15423^T and 25HG05S-40^T, were isolated from the root of a halophyte and from a riverbank soil in the Republic of Korea, respectively. Cells of both strains were Gram-stain-negative, yellow-pigmented, non-motile, and rod-shaped. Phylogenetic analysis based on 16S rRNA gene sequences revealed that both strains belong to the genus Flavobacterium. Strains HNIBRBA15423^T and 25HG05S-40^T showed the highest sequence similarity to Flavobacterium jejuense EC11^T (98.5%) and Flavobacterium dankookense ARSA-19^T (98.3%), respectively. The major cellular fatty acids of both strains included iso-C_15:0, iso-C_15:1 G, and iso-C_17:0 3-OH. Both strains contained menaquinone-6 as the respiratory quinone and phosphatidylethanolamine as the major polar lipid. The complete genome sizes and DNA G + C contents were 4.29 Mb and 29.7% for strain HNIBRBA15423^T, and 3.45 Mb and 36.6% for strain 25HG05S-40^T. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values were calculated. For HNIBRBA15423^T, ANI value compared to F. jejuense EC11^T were 85.2% with dDDH value of 29.5%. For 25HG05S-40^T, ANI values compared to F. dankookense DSM 25687^T and F. wongokense WG47^T were 76.0% and 78.6%, respectively, with dDDH value of 20.3% and 21.5%. Based on the polyphasic taxonomic data, strains HNIBRBA15423^T and 25HG05S-40^T represent two novel species within the genus Flavobacterium, for which the names Flavobacterium suaedicola sp. nov. and Flavobacterium wonjuense sp. nov. are proposed.

Aeromonas hydrophila (A. hydrophila) is an infectious agent that can infect both fish and humans, posing significant threats to aquaculture and public health. Iron acquisition is essential for bacterial survival, colonization, and pathogenicity, as it is crucial to many metabolic and enzymatic processes. Ferrous iron transporter B (FeoB) is a major component of the bacterial iron uptake system, mediating the transport of ferrous iron (Fe²⁺) and playing a key role in cellular iron homeostasis. The present study elucidates the role of FeoB in iron utilization, bacterial physiology, and pathogenicity of A. hydrophila ATCC 7966. A stable feoB-deleted mutant strain (AhΔfeoB) and its complemented strain (CΔfeoB) were constructed. Our results demonstrated that deletion of feoB impaired ferrous‑iron accumulation and substrate affinity, significantly increased sensitivity to clindamycin, sodium deoxycholate, and oxidative stress, reduced biofilm formation, and downregulated biofilm-associated genes. Furthermore, loss of the feoB gene resulted in abnormal cellular morphology and altered expression of 12 out of 15 tested virulence-related genes. Unlike in previous reports, AhΔfeoB showed no significant differences in growth characteristics, hemolytic activity and virulence in a BALB/c mouse infection model under iron-limited conditions. Moreover, DIA-based proteomic analysis revealed that feoB is a core protein essential for iron homeostasis, and its deletion profoundly impacts bacterial metabolism, adaptability, and iron transport. These findings emphasize the central role of FeoB in iron homeostasis and in the regulation of critical physiological functions in A. hydrophila ATCC 7966.

Neuraminidase (NA) is increasingly recognized as a promising target antigen for improving the breadth and durability of influenza vaccines, yet NA-based mRNA vaccines remain comparatively unexplored relative to hemagglutinin-based approaches. Here, we applied a computationally guided NA antigen-design strategy to seasonal H3N2 influenza viruses and investigated whether epitope-guided optimization could improve the immunogenicity and protective efficacy of NA-based mRNA vaccines. NA-D3, an NA antigen designed based on the evolutionary characteristics of circulating H3N2 viruses, was first evaluated in an mRNA vaccine. This vaccine provided partial protection against H3N2 challenge and reduced viral replication in the lungs, although detectable neuraminidase inhibition (NAI) activity was not observed. To further improve NA antigen immunogenicity, predicted B- and T-cell epitopes were incorporated into the antigen design process, resulting in three sequentially optimized NA candidates, F0, F1, and F2. In a subsequent challenge experiment, F1 and F2 conferred complete protection, achieving 100% survival and significantly lower viral RNA levels and infectious viral titers in the lungs compared to controls. The optimized NA mRNA vaccines also induced detectable NAI activity against heterologous H3N2 viruses, albeit at relatively modest levels. Collectively, these findings demonstrate the protective potential of NA-based mRNA vaccination against H3N2 influenza viruses and establish iterative, epitope-guided strategy in NA antigen optimization – integrating computational prediction with experimental validation – as an effective approach for developing broadly protective NA-based mRNA vaccines.