Journal of Microbiology

Journal Article

Environmental Adaptation of Psychrophilic Bacteria Subtercola spp. Isolated from Various Cryospheric Habitats: Hanbyul Lee , Yong-Joon Cho , Ahnna Cho , Ok-Sun Kim; J. Microbiol. 2023;61(7):663-672. Published online August 24, 2023; DOI: https://doi.org/10.1007/s12275-023-00068-y

Abstract: Subtercola boreus K300T is a novel psychrophilic strain that was isolated from permanently cold groundwater in Finland and has also been found in several places in Antarctica including lake, soil, and rocks. We performed genomic and transcriptomic analyses of 5 strains from Antarctica and a type strain to understand their adaptation to different environments. Interestingly, the isolates from rocks showed a low growth rate and smaller genome size than strains from the other isolation sources (lake, soil, and groundwater). Based on these habitat-dependent characteristics, the strains could be classified into two ecotypes, which showed differences in energy production, signal transduction, and transcription in the clusters of orthologous groups of proteins (COGs) functional category. In addition, expression pattern changes revealed differences in metabolic processes, including uric acid metabolism, DNA repair, major facilitator superfamily (MFS) transporters, and xylose degradation, depending on the nutritional status of their habitats. These findings provide crucial insights into the environmental adaptation of bacteria, highlighting genetic diversity and regulatory mechanisms that enable them to thrive in the cryosphere.

Research Support, Non-U.S. Gov'ts

Fine Mapping of a Foot-and-Mouth Disease Virus Epitope Recognized by Serotype-Independent Monoclonal Antibody 4B2: Yongzhong Yu , Haiwei Wang , Lei Zhao , Chunyuan Zhang , Zhigang Jiang , Li Yu; J. Microbiol. 2011;49(1):94-101. Published online March 3, 2011; DOI: https://doi.org/10.1007/s12275-011-0134-1

Abstract: VP2 is a structural protein of the foot-and-mouth disease virus (FMDV). In this study, a FMDV serotype-independent monoclonal antibody (MAb), 4B2, was generated. By screening a phage-displayed random 12-peptide library, we found positive phages displaying the consensus motif ETTXLE (X is any amino acid (aa)), which is highly homologous to 6ETTLLE11 at the N-terminus of the VP2 protein. Subsequently, a series of GST-fusion proteins expressing a truncated N-terminus of VP2 were examined by western blot analysis using the MAb 4B2. The results indicated that the motif 6ETTLLE11 of VP2 may be the minimal requirement of the epitope recognized by 4B2. Moreover, a 12-aa peptide 2KKTEETTLLEDR13 was shown to be the minimal unit of the epitope with maximal binding activity to 4B2. Alanine-scanning analysis demonstrated thatThr7, Thr8, and Leu10 are the functional residues of the 4B2 epitope Glu6 and Leu9 are required residues, and Glu11 plays a crucial role in the binding of MAb 4B2. The fine mapping of the epitope indicated that MAb 4B2 has the potential to be used in FMDV diagnosis.

Identification of a Novel Linear B-Cell Epitope in the M Protein of Avian Infectious Bronchitis Coronaviruses: Junji Xing , Shengwang Liu , Zongxi Han , Yuhao Shao , Huixin Li , Xiangang Kong; J. Microbiol. 2009;47(5):589-599. Published online October 24, 2009; DOI: https://doi.org/10.1007/s12275-009-0104-z

Abstract: This report describes the identification of a novel linear B-cell epitope at the C-terminus of the membrane (M) protein of avian infectious bronchitis virus (IBV). A monoclonal antibody (MAb) (designated as 15E2) against the IBV M protein was prepared and a series of 14 partially-overlapping fragments of the IBV M gene were expressed with a GST tag. These peptides were subjected to enzyme-linked immunosorbent assay (ELISA) and western blotting analysis using MAb 15E2 to identify the epitope. A linear motif, 199FATFVYAK206, which was located at the C-terminus of the M protein, was identified by MAb 15E2. ELISA and western blotting also showed that this epitope could be recognized by IBV-positive serum from chicken. Given that 15E2 showed reactivity with the 199FATFVYAK206 motif, expressed as a GST fusion protein, in both western blotting and in an ELISA, we proposed that this motif represented a linear B-cell epitope of the M protein. The 199FATFVYAK206 motif was the minimal requirement for reactivity as demonstrated by analysis of the reactivity of 15E2 with several truncated peptides that were derived from the motif. Alignment and comparison of the 15E2-defined epitope sequence with the sequences of other coronaviruses indicated that the epitope is well conserved among chicken and turkey coronaviruses. The identified epitope should be useful in clinical applications and as a tool for the further study of the structure and function of the M protein of IBV.

A Novel Immunodominant Epitope on aouter Membrane protein F of Pseudomonas aeruginosa in Humans: Park, Wan Je , Lee, Na Gyong , Jung, Sang Bo , Ahn, Bo Young , Kim, Yu Sam , Kim, Hyun Su; J. Microbiol. 1998;36(1):49-54.

Abstract: The outer membrane protein F(OprF) of Pseudomonas aeruginosa is known to be conserved among various P. aeruginosa strains, and has been shown to be protective against P. aeruginosa infections in animal model systems. In order to identify epitopes essential for immunogenicity and protective efficacy, we synthesized 14 peptides of the mature OprF protein and evaluated their immunofenicity in mice. Among them two peptides in the carboxy-terminus region of OprF, peptide 3(^204GAPAVAEVVRVQLDVKFD^221) and peptide 14(^305NATAEGRAINRRVE^318), elicited high titer of antibody responses in mices, and reacted strongly with anti-OprF antibodies. The peptides were also examined for reactivity with antisera from human volunteers immunized with a P. aeruginosa vaccine composed of outer membrane proteins and from patients who recovered from Pseudomons infections. Peptide 3 showed high reactivity with both antisera from the vaccines and the convalescents, comparable to that of peptide 14, which has been previously reported to afford protection against P. aeruginosa in a murine acute infection model. Substitution of three amino acids KFD in peptide 3 with AAA significantly diminished its reactivity to the antisera, indicating that the core sequence ^216LDVKFD^221 is crucial for its immunogenicity and reactivity with human antisera. These data suggest a potential use of this peptide for development of a vaccine against P. aeruginosa infection.

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