Journal of Microbiology

Journal Articles

The periplasmic chaperone protein Psg_2795 contributes to the virulence of Pseudomonas savastanoi pv. glycinea: the causal agent of bacterial blight of soybean: Xiuhua Wang , Xiaoyan Zhang , Bao-Hui Lu , Jie Gao; J. Microbiol. 2022;60(5):478-487. Published online March 4, 2022; DOI: https://doi.org/10.1007/s12275-022-1469-5

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Abstract: Pseudomonas savastanoi pv. glycinea (Psg, also named P. syringae pv. glycinea and P. amygdali pv. glycinea) is the causative agent of bacterial blight in soybean. The identification of virulence factors is essential for understanding the pathogenesis of Psg. In this study, a mini-Tn5 transposon mutant library of Psg strain PsgNC12 was screened on soybean, and one low-virulent mini-Tn5 mutant, designated as 4573, was identified. Sequence analysis of the 4573-mutant revealed that the mini-Tn5 transposon was inserted in the Psg_2795 gene. Psg_2795 encodes a FimC-domain protein that is highly conserved in Pseudomonas. Further analysis revealed that the mutation and knockout of Psg_2795 results in a reduced virulence phenotype on soybean, decreased motility, weakened bacterial attachment to a glass surface and delayed the population growth within soybean leaves. The phenotype of the 4573-mutant could be complemented nearly to wild-type levels using an intact Psg_2795 gene. Collectively, our results demonstrate that Psg_2795 plays an important role in the virulence, motility, attachment and the population growth of PsgNC12 in soybean. This finding provides a new insight into the function of periplasmic chaperone proteins in a type I pilus and provides reference information for identifying Psg_2795 homologues in P. savastanoi and other bacteria.

Evolutionary analysis and protein family classification of chitin deacetylases in Cryptococcus neoformans: Seungsue Lee , Hyun Ah Kang , Seong-il Eyun; J. Microbiol. 2020;58(9):805-811. Published online September 1, 2020; DOI: https://doi.org/10.1007/s12275-020-0288-9

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Abstract: Cryptococcus neoformans is an opportunistic fungal pathogen causing cryptococcal meningoencephalitis. Interestingly, the cell wall of C. neoformans contains chitosan, which is critical for its virulence and persistence in the mammalian host. C. neoformans (H99) has three chitin deacetylases (CDAs), which convert chitin to chitosan. Herein, the classification of the chitin-related protein (CRP) family focused on cryptococcal CDAs was analyzed by phylogenetics, evolutionary pressure (dN/dS), and 3D modeling. A phylogenetic tree of 110 CRPs revealed that they can be divided into two clades, CRP I and II with bootstrap values (> 99%). CRP I clade comprises five groups (Groups 1–5) with a total of 20 genes, while CRP II clade comprises sixteen groups (Groups 6–21) with a total of 90 genes. CRP I comprises only fungal CDAs, including all three C. neoformans CDAs, whereas CRP II comprises diverse CDAs from fungi, bacteria, and amoeba, along with other carbohydrate esterase 4 family proteins. All CDAs have the signal peptide, except those from group 11. Notably, CDAs with the putative O-glycosylation site possess either the glycosylphosphatidylinositol (GPI)-anchor motif for CRP I or the chitin-binding domain (CBD) for CRP II, respectively. This evolutionary conservation strongly indicates that the O-glycosylation modification and the presence of either the GPI-anchor motif or the chitin-binding domain is important for fungal CDAs to function efficiently at the cell surface. This study reveals that C. neoformans CDAs carrying GPI anchors have evolved divergently from fungal and bacterial CDAs, providing new insights into evolution and classification of CRP family.

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

Prevalence of Human Papillomavirus Infection and Genotype Distribution Determined by the Cyclic-Catcher Melting Temperature Analysis in Korean Medical Checkup Population: Yun-Jee Kim , Min-Jung Kwon , Hee-Yeon Woo , Soon-Young Paik; J. Microbiol. 2013;51(5):665-670. Published online September 14, 2013; DOI: https://doi.org/10.1007/s12275-013-3160-3

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Abstract: Although cytology screening has reduced the incidence and mortality rate of cervical cancer significantly, its usefulness is limited to samples from the site of the lesion, resulting in its low sensitivity and unsuitability for use in medical checkups. The purpose of the present study was to evaluate the prevalence of HPV infection using genotype distribution and to analyze the correlation of the HPV DNA test results with cytological results. We also evaluated the benefits of quantitative information obtained from cyclic-catcher melting temperature analysis (CMTA) in screening for cervical cancer. We performed cyclic-CMTA using AnyplexTM II HPV28 Detection in combination with cervical cytology for 2,181 subjects. The following HPV positivity types were detected using cyclic-CMTA and HPV positivity was found to increase together with the severity of the cytology results: (1) For 419 HPV positive specimens, HPV DNA was detected in 18.1% of normal specimens, 78.3% of ASCUS, and all of LSIL and HSIL; (2) high-risk HPV DNAs were detected in 63.3% of normal (N=547), 65.9% of ASCUS (N=41), 76.9% of LSIL (N=13), and 88.9% of HSIL (N=9) among total detected HPV DNA regardless multiple detection; (3) multiple HPV genotypes were detected in 4.8% of normal specimens (N=2,146), 52.2% of ASCUS (N=23), 57.1% of LSIL (N=7), and 40.0% of HSIL (N=5). In addition, a high level of viral DNA was observed using cyclic-CMTA in all specimens beyond the LSIL stage according to cytology, while only 6% of specimens with normal cytology showed a correlation with viral quantitation by cyclic-CMTA. The combination of HPV genotyping with a quantitative assay and cytology will allow for a more accurate diagnosis of cervical cancer.

Enhancement of Immunotherapeutic Effects of HPV16E7 on Cervical Cancer by Fusion with CTLA4 Extracellular Region: Yi Zheng , Yijuan Zhang , Jun Wan , Chaofan Shi , Laiqiang Huang; J. Microbiol. 2008;46(6):728-736. Published online December 24, 2008; DOI: https://doi.org/10.1007/s12275-008-0087-1

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17 Citations

Abstract: Cervical cancer is caused by infection by high-risk human papillomavirus (HPV), especially HPV16. Limitations in current treatments of cervical cancers call for the development of new and improved immunotherapies. This study aims at investigating the efficacy of a novel vaccine consisting of modified HPV 16E7 fused with human cytotoxic T-lymphocyte antigen 4 (CTLA4). The regions in HPV16 E7 gene associated with its transformation and CTL-enhanced response were modified; the resultant HPV16mE7 was fused with extracellular region of CTLA4 to generate HPVm16E7-eCTLA4 fusion protein. Binding of this fusion protein to B7 molecules expressed on antigen presenting-cells (APCs) was demonstrated. C57BL/6 (H-2b) mice immunized with low dose of the fusion protein (10 μg) produced higher titer antibody and stronger specific CTL response, and expressed higher levels of IFN-γ and IL-12, compared with those immunized with HPVm16E7 only or admixture of HPVm16E7 and CTLA4, or PBS; and were protected from lethal dose tumor challenge. Tumor growth was retarded and survival prolonged in mouse models with the fusion protein treatment. Our results demonstrate that fusion of HPV16 E7 with eCTLA4 targeting APCs resulted in enhanced immunity, and that this fusion protein may be useful for improving the efficacy of immunotherapeutic treatments of cervical cancer and other HPV16 infection-associated tumors.

Retraction of Publication

Retraction Note to: Cryptic prophages in a blaNDM‑1‑bearing plasmid increase bacterial survival against high NaCl concentration, high and low temperatures, and oxidative and immunological stressors: So Yeon Kim , Kwan Soo Ko; J. Microbiol. 2023;61(4):481-481.; DOI: https://doi.org/10.1007/s12275-023-00049-1

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Abstract: Retraction Note to: Journal of Microbiology (2020) Vol. 58, No. 6, pp. 483–488 https://doi.org/10.1007/s12275-020-9605-6 The Editor-in-Chief has retracted this article at the request of the authors. After publication concerns were raised that prophage sequences do not exist in the genome of the plasmid pNDM-A1 used in this study. The authors have not been able to confirm the existence of prophage sequences in the plasmid. As a result, the Editor-in-Chief no longer has confidence in the results and conclusions presented in this article. Kwan Soo Ko agrees with this retraction. So Yeon Kim has not responded to correspondence from the Editor-in-Chief about this retraction.

Production and Prophylactic Efficacy Study of Human Papillomavirus-like Particle Expressing HPV16 L1 Capsid Protein: Jie-Yun Park , Hyun-Mi Pyo , Sun-Woo Yoon , Sun-Young Baek , Sue-Nie Park , Chul-Joong Kim , Haryoung Poo; J. Microbiol. 2002;40(4):313-318.

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Abstract: To perform the prophylactic study of a vaccine derived from human papillomavirus (HPV) using Balb/c mice, we produced virus like particles consisting of HPV capsid protein L1 which has been reported to induce significant humoral and cellular immunity using various animal model systems. In order to produce HPV16 VLPs, the cDNA of L1 capsid protein in HPV type 16, obtained by polymerase chain reaction, was inserted into yeast expression vector, YEG[alpha]-HIR525 under the control of GAL10 promoter. The transformation of YEG[alpha]-HPV16 L1 was performed into the yeast Saccharomyces cerevisiae Y2805 by the lithium acetate method and the yeast clone expressing the highest level of L1 capsid protein of human papillomavirus type 16 was selected by Western blot analysis using anti-HPV16 L1 antibody. The purification of HPV16 VLP has been performed by the ultracentrifugation and gel-filtration methods. To validate the vaccine efficacy of the purified HPV16 VLPs and investigate the properties of HPV16 VLPs to induce humoral immunity, ELISA assay was performed. A significantly increased production of anti-HPV16 VLP antibodies was observed in sera from immunized mice. The neutralization activity of antibodies in the sera from the vaccinated mice was demonstrated by a rapid and simple assay to detect hemagglutihation inhibition activity

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