Journal of Microbiology

Journal Articles

Non-Mitochondrial Aconitase-2 Mediates the Transcription of Nuclear-Encoded Electron Transport Chain Genes in Fission Yeast: Ho-Jung Kim, Soo-Yeon Cho, Soo-Jin Jung, Yong-Jun Cho, Jung-Hye Roe, Kyoung-Dong Kim; J. Microbiol. 2024;62(8):639-648. Published online June 25, 2024; DOI: https://doi.org/10.1007/s12275-024-00147-8

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Abstract: Aconitase-2 (Aco2) is present in the mitochondria, cytosol, and nucleus of fission yeast. To explore its function beyond the well-known role in the mitochondrial tricarboxylic acid (TCA) cycle, we conducted genome-wide profiling using the aco2ΔNLS mutant, which lacks a nuclear localization signal (NLS). The RNA sequencing (RNA-seq) data showed a general downregulation of electron transport chain (ETC) genes in the aco2ΔNLS mutant, except for those in the complex II, leading to a growth defect in respiratory-prone media. Complementation analysis with non-catalytic Aco2 [aco2ΔNLS + aco2(3CS)], where three cysteines were substituted with serine, restored normal growth and typical ETC gene expression. This suggests that Aco2's catalytic activity is not essential for its role in ETC gene regulation. Our mRNA decay assay indicated that the decrease in ETC gene expression was due to transcriptional regulation rather than changes in mRNA stability. Additionally, we investigated the Php complex's role in ETC gene regulation and found that ETC genes, except those within complex II, were downregulated in php3Δ and php5Δ strains, similar to the aco2ΔNLS mutant. These findings highlight a novel role for nuclear aconitase in ETC gene regulation and suggest a potential connection between the Php complex and Aco2.

Recombinant Protein Mimicking the Antigenic Structure of the Viral Surface Envelope Protein Reinforces Induction of an Antigen‑Specific and Virus‑Neutralizing Immune Response Against Dengue Virus: Ju Kim , Tae Young Lim , Jisang Park , Yong&#; J. Microbiol. 2023;61(1):131-143. Published online February 1, 2023; DOI: https://doi.org/10.1007/s12275-023-00021-z

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Dengue virus (DENV), belonging to the family Flaviviridae, is the causative agent of dengue and comprises four serotypes. A second heterologous DENV infection is a critical risk factor for severe dengue, and no effective vaccine is available to prevent infection by all four DENV serotypes. Recombinant DENV vaccines are primarily based on the envelope proteins, prM and E. The E protein and its envelope domain III (EDIII) have been investigated as candidate antigens (Ags) for recombinant subunit vaccines. However, most EDIII-based Ags are monomers that do not display the cognate antigenic structure of E protein, which is essential for induction of virus-neutralizing immunity. Here, we developed recombinant DENV-2 envelope domain (r2ED) protein as an Ag that mimics the quaternary structure of E protein on the DENV surface. We confirmed that r2ED retained the conformational epitope displayed at the E-dimer interface, which reportedly exhibits broad virus-neutralizing capacity, without displaying the fusion loop epitope that causes antibody (Ab)-dependent enhancement. Furthermore, compared with EDIII alone, r2ED elicited stronger Ag-specific and cross-reactive neutralizing Ab and T cell-mediated immune responses in mice. This Ag-specific immunity was maintained at an elevated level 6 months after the last immunization, suggesting sustained Ag-specific immune memory. Taken together, these observations suggest that r2ED could be used to develop an improved subunit vaccine capable of inducing a broadly cross-reactive and long-lasting immune response against DENV infection.

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Peptides of a Feather: How Computation Is Taking Peptide Therapeutics under Its Wing
Thomas David Daniel Kazmirchuk, Calvin Bradbury-Jost, Taylor Ann Withey, Tadesse Gessese, Taha Azad, Bahram Samanfar, Frank Dehne, Ashkan Golshani
Genes.2023; 14(6): 1194. CrossRef

Repositioning of a mucolytic drug to a selective antibacterial against Vibrio cholerae: In-Young Chung† , Bi-o Kim† , Hye-Jeong Jang† , You-Hee Cho; J. Microbiol. 2020;58(1):61-66. Published online January 2, 2020; DOI: https://doi.org/10.1007/s12275-020-9590-9

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Abstract

Drug repositioning, the approach to explore existing drugs for use in new therapeutic indications, has emerged as an alternative drug development strategy. In this study, we found that a mucolytic drug, N-acetylcysteine (NAC) showed antibacterial activity against Vibrio cholerae. NAC can provide acid stress that selectively inhibited the growth of V. cholerae among other bacterial pathogens. To address the antibacterial mechanism of NAC against V. cholerae, six acr (acetylcysteine- resistant) mutants were isolated from 3,118 random transposon insertion clones. The transposon insertion sites of the six mutants were mapped at the five genes. All these mutants did not display NAC resistance under acidic conditions, despite their resistance to NAC under alkaline conditions, indicating that the NAC resistance directed by the acr mutations was independent of the unusual pH-sensitivity of V. cholerae. Furthermore, all these mutants displayed attenuated virulence and reduced biofilm formation, suggesting that the acr genes are required for pathogenesis of V. cholerae. This study validates the relevance of drug repositioning for antibacterials with new modes of action and will provide an insight into a novel antibacterial therapy for V. cholerae infections to minimize side effects and resistance emergence.

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Identification of brevinin-1EMa-derived stapled peptides as broad-spectrum virus entry blockers
Mi Il Kim, Thanh K. Pham, Dahee Kim, Minkyung Park, Bi-o Kim, You-Hee Cho, Young-Woo Kim, Choongho Lee
Virology.2021; 561: 6. CrossRef

Amino acid residues in the Ler protein critical for derepression of the LEE5 promoter in enteropathogenic E. coli: Su-Mi Choi , Jae-Ho Jeong , Hyon E. Choy , Minsang Shin; J. Microbiol. 2016;54(8):559-564. Published online August 2, 2016; DOI: https://doi.org/10.1007/s12275-016-6027-6

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Abstract

Enteropathogenic E. coli causes attaching and effacing (A/E) intestinal lesions. The genes involved in the formation of A/E lesions are encoded within a chromosomal island comprising of five major operons, LEE1-5. The global regulator H-NS represses the expression of these operons. Ler, a H-NS homologue, counteracts the H-NS–mediated repression. Using a novel genetic approach, we identified the amino acid residues in Ler that are involved in the interaction with H-NS: I20 and L23 in the C-terminal portion of α-helix 3, and I42 in the following unstructured linker region.

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Regulation of the Locus of Enterocyte Effacement in Attaching and Effacing Pathogens
R. Christopher D. Furniss, Abigail Clements, William Margolin
Journal of Bacteriology.2018;[Epub] CrossRef

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

NOTE] Isolation and Characterization of Histamine-Producing Bacteria from Fermented Fish Products: Jin Seok Moon , So-Young Kim , Kyung-Ju Cho , Seung-Joon Yang , Gun-Mook Yoon , Hyun-Ju Eom , Nam Soo Han; J. Microbiol. 2013;51(6):881-885. Published online December 19, 2013; DOI: https://doi.org/10.1007/s12275-013-3333-0

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Abstract

Histamine is mainly produced by microorganisms that are found in fermented foods, and is frequently involved in food poisoning. Two histamine-producing bacteria were isolated from fermented fish products, anchovy sauce, and sand lance sauce by using a histidine decarboxylating medium. The species were identified as Bacillus licheniformis A7 and B. coagulans SL5. Multiplex PCR analysis showed the presence of the conserved histidine decarboxylase (hdc) gene in the chromosome of these bacteria. B. licheniformis A7 and B. coagulans SL5 produced the maximum amount of histamine (22.3±3.5 and 15.1±1.5 mg/L, respectively). As such, they were determined to be potential histamine-producing bacteria among the tested cultures.

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Low salt and biogenic amines fermented fish sauce (Mahyaveh) as potential functional food and ingredient
Hoda Ghayoomi, Mohammad Bagher Habibi Najafi, Mohammad Reza Edalatian Dovom, Amir Pourfarzad
LWT.2023; 182: 114801. CrossRef
Histamine-degrading halophilic bacteria from traditional fish sauce: Characterization of Virgibacillus campisalis TT8.5 for histamine reduction
Thi Thu Hang Tran, Thi Phuong Anh Nguyen, Thi Diu Pham, Thi Hong Nguyen, Thi Lam Doan Nguyen, Thi Thanh Thuy Nguyen, Thi Lan Huong Tran, Trung Khoa Giang, Thi Thu Hien Bui, Bien-Cuong Do, Tien-Thanh Nguyen, Dietmar Haltrich, Hoang Anh Nguyen
Journal of Biotechnology.2023; 366: 46. CrossRef
Detection, Identification, and Inactivation of Histamine-forming Bacteria in Seafood: A Mini-review
Daniel Lance Nevado, Sophia Delos Santos, Gelian Bastian, Jimson Deyta, El-jay Managuelod, Jamil Allen Fortaleza, Rener De Jesus
Journal of Food Protection.2023; 86(3): 100049. CrossRef
Influence of polyamine production and proteolytic activities of co-cultivated bacteria on histamine production by Morganiella morganii
Suma Devivilla, Manjusha Lekshmi, Fathima Salam, Sanath Kumar H, Rajendran Kooloth Valappil, Sibnarayan Dam Roy, Binaya Bhusan Nayak
The Journal of General and Applied Microbiology.2022; 68(5): 213. CrossRef
Isolation and Identification of Aroma-producing Yeast from Mackerel Fermentation Broth and Its Fermentation Characteristics
Yu Wu, Xiao’e Chen, Xubo Fang, Lili Ji, Fang Tian, Hui Yu, Yan Chen
Journal of Aquatic Food Product Technology.2021; 30(10): 1264. CrossRef
Effect of fermentation by Aspergillus oryzae on the biochemical and sensory properties of anchovy (Engraulis japonicus) fish sauce
Jianan Sun, Xiaohang Yu, Bohuan Fang, Lei Ma, Changhu Xue, Zhaohui Zhang, Xiangzhao Mao
International Journal of Food Science & Technology.2016; 51(1): 133. CrossRef
Characterization of Tryptamine-Producing Bacteria Isolated from Commercial Salted and Fermented Sand Lance Ammodytes personatus Sauces
In-Seon Um, Tae-Ok Kim, Hee-Dai Kim, Kwon-Sam Park
Korean Journal of Fisheries and Aquatic Sciences.2016; 49(6): 792. CrossRef
Relationship between chemical characteristics and bacterial community of a Korean salted-fermented anchovy sauce, Myeolchi-Aekjeot
Hae-Won Lee, Yun-Jeong Choi, In Min Hwang, Sung Wook Hong, Mi-Ai Lee
LWT.2016; 73: 251. CrossRef
Isolation and Characterization of Putrescine-producing Bacteria in Commercially Available Sauces Made from Salted and Fermented Sand Lance Ammodytes personatus
In-Seon Um, Tae-Ok Kim, Kwon-Sam Park
Korean Journal of Fisheries and Aquatic Sciences.2016; 49(5): 573. CrossRef

NOTE] The Activity of Phosphoinositide-Specific Phospholipase C Is Required for Vegetative Growth and Cell Wall Regeneration in Coprinopsis cinerea: Young Taek Oh , Chun-Seob Ahn , Kyung-Jin Lee , Jeong-Geun Kim , Hyeon-Su Ro , Jae Won Kim , Chang-Won Lee; J. Microbiol. 2012;50(4):689-692. Published online August 25, 2012; DOI: https://doi.org/10.1007/s12275-012-2004-x

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Abstract: Three isotypes of phosphoinositide-specific phospholipase C designated CcPLC1, CcPLC2, and CcPLC3 were identified in Coprinopsis cinerea, through a search of the genome sequence database. The functional role of the PI-PLCs were studied by using U73122, which specifically inhibits the activity of PI-PLC. The specificity of the inhibitor effect was confirmed by using an inactive structural analog U73433. The inhibition of PI-PLCs activity resulted in severely retarded germination of basidiospores and oidia, reduced hyphal growth, knobbly hyphal tips with many irregular side branches, and aberrant (branch-like structure) clamp cells. Furthermore, U73122 definitely inhibited cell wall formation. Here we report that PI-PLCs play important roles in various aspects of C. cinerea biology.

Comparative Approach to Capture Bacterial Diversity of Coastal Waters: Hyunsoo Na , Ok-Sun Kim , Seok-Hwan Yoon , Yunmin Kim , Jongsik Chun; J. Microbiol. 2011;49(5):729-740. Published online November 9, 2011; DOI: https://doi.org/10.1007/s12275-011-1205-z

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Abstract: Despite the revolutionary advancements in DNA sequencing technology and cultivation techniques, few studies have been done to directly compare these methods. In this study, a 16S rRNA gene-based, integrative approach combining culture-independent techniques with culture-dependent methods was taken to investigate the bacterial community structure of coastal seawater collected from the Yellow Sea, Korea. For culture-independent studies, we used the latest model pyrosequencer, Roche/454 Genome Sequencer FLX Titanium. Pyrosequencing captured a total of 52 phyla including 27 candidate divisions from the water column, whereas the traditional cloning approach captured only 15 phyla including 2 candidate divisions. In addition, of 878 genera retrieved, 92.1% of the sequences were unique to pyrosequencing. For culture-dependent analysis, plate culturing, plate washing, enrichment, and high-throughput culturing (HTC) methods were applied. Phylogenetic analysis showed that the plate-washing clones formed a cluster devoid of any previously cultured representatives within the family Rhodobacteraceae. One HTC isolate (SF293) fell into the OM182 clade, which was not recovered by other culturing methods described here. By directly comparing the sequences obtained from cultures with those from culture-independent work, we found that only 33% of the culture sequences were identical to those from clone libraries and pyrosequences. This study presents a detailed comparison of common molecular and cultivation techniques available in microbial ecology. As different methods yielded different coverage, we suggest choosing the approach after carefully examining the scientific questions being asked.

Resistance to Macrolide, Lincosamide and Streptogramin Antibiotics in Staphylococci Isolated in Istanbul, Turkey: Zerrin Aktas , Aslihan Aridogan , Cigdem Bal Kayacan , Derya Aydin; J. Microbiol. 2007;45(4):286-290.; DOI: https://doi.org/2571 [pii]

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Abstract: The purpose of this study was to investigate the prevalence and genetic mechanisms of erythromycin resistance in staphylococci. A total of 102 erythromycin resistant non-duplicate clinical isolates of staphylococci [78 coagulase negative stapylococci (CNS), 24 Staphylococcus aureus] were collected between October 2003 and August 2004 in Istanbul Faculty of Medicine in Turkey. The majority of the isolates were from blood and urine specimens. Antimicrobial susceptibilities were determined by the agar dilution procedure and the resistance phenotypes by the double disk induction test. A multiplex PCR was performed, using primers specific for erm(A), erm(B), erm(C), and msrA genes. Among the 78 CNS isolates, 57.8% expressed the MLSB-constitutive, 20.6% the MLSB-inducible, and 21.6% the MSB phenotypes. By PCR, 78.2% of these isolates harbored the erm(C) gene, 8.9% erm(A), 6.4% erm(B), and 11.5% msrA genes. In S. aureus, the constitutive MLSB (58.3%) was more common than the inducible phenotype (20.8%). erm(A) was detected in 50% and erm(C) in 62.5% of the isolates, while 37.5% contained both erm(A) and erm(C). erm(C)-associated macrolide resistance was the most prevalent in CNS, while erm(C) and erm(A, C) was the most prevalent in S. aureus.

Dominance of Endospore-forming Bacteria on a Rotating Activated Bacillus Contactor Biofilm for Advanced Wastewater Treatment: Seong Joo Park , Jerng Chang Yoon , Kwang-Soo Shin , Eung Ho Kim , Soobin Yim , Yeon-Je Cho , Gi Moon Sung , Dong-Geun Lee , Seung Bum Kim , Dong-Uk Lee , Sung-Hoon Woo , Ben Koopman; J. Microbiol. 2007;45(2):113-121.; DOI: https://doi.org/2525 [pii]

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Abstract: The bacterial diversity inherent to the biofilm community structure of a modified rotating biological contactor wastewater treatment process, referred to as the Rotating Activated Bacillus Contactor (RABC) process, was characterized in this study, via both culture-dependent and culture-independent methods. On the basis of culture-dependent methods, Bacillus sp. were found to exist in large numbers on the biofilm (6.5% of the heterotrophic bacteria) and the microbial composition of the biofilms was quite simple. Only three phyla were identified-namely, the Proteobacteria, the Actinobacteria (High G+C Gram-positive bacteria), and the Firmicutes (Low G+C Gram-positive bacteria). The culture-independent partial 16S rDNA sequence analysis revealed a considerably more diverse microbial composition within the biofilms. A total of eight phyla were recovered in this case, three of which were major groups: the Firmicutes (43.9%), the Proteobacteria (28.6%), and the Bacteroidetes (17.6%). The remaining five phyla were minor groups: the Planctomycetes (4.4%), the Chlorobi (2.2%), the Actinobacteria (1.1%), the Nitrospirae (1.1%), and the Verrucomicrobia (1.1%). The two most abundant genera detected were the endospore-forming bacteria (31.8%), Clostridium and Bacillus, both of which are members of the Firmicutes phylum. This finding indicates that these endospore-forming bacteria successfully colonized and dominated the RABC process biofilms. Many of the colonies or clones recovered from the biofilms evidenced significantly high homology in the 16S rDNA sequences of bacteria stored in databases associated with advanced wastewater treatment capabilities, including nitrification and denitrification, phosphorus accumulation, the removal of volatile odors, and the removal of chlorohydrocarbons or heavy metals. The microbial community structures observed in the biofilms were found to correlate nicely with the enhanced performance of advanced wastewater treatment protocols.

Journal Article

Protective Immune Response of Bacterially-Derived Recombinant FaeG in Piglets: Huang Yahong , Wanqi Liang , Aihu Pan , Zhiai Zhou , Qiang Wang , Cheng Huang , Jianxiu Chen , Dabing Zhang; J. Microbiol. 2006;44(5):548-555.; DOI: https://doi.org/2442 [pii]

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Abstract: FaeG is the key factor in the infection process of K88ad enterotoxigenic Escherichia coli(ETEC) fimbrial adhesin. In an attempt to determine the possibility of expressing recombinant FaeG with immunogenicity for a new safe and high-production vaccine in E. coli, we constructed the recombinant strain, BL21 (DE3+K88), which harbors an expression vector with a DNA fragment of faeG, without a signal peptide. Results of 15% SDS-polyacrylamide slab gel analysis showed that FaeG can be stably over-expressed in BL21 (DE3+K88) as inclusion bodies without FaeE. Immunoglobulin G (IgG) and M (IgM) responses in pregnant pigs, with boost injections of the purified recombinant FaeG, were detected 4 weeks later in the sera and colostrum. An in vitro villius-adhesion assay verified that the elicited antibodies in the sera of vaccinated pigs were capable of preventing the adhesion of K88ad ETEC to porcine intestinal receptors. The protective effect on the mortality rates of suckling piglets born to vaccinated mothers was also observed one week after oral challenge with the virulent ETEC strain, C83907 (K88ad, CT+, ST+). The results of this study proved that the adhesin of proteinaceous bacterial fimbriae or pili could be overexpressed in engineered E. coli strains, with protective immune responses to the pathogen.

Bioluminescent Assay of Phospholipase C Using A Luminescent Marine Mutant Bacterium Vibrio harveyi M-17: Ki Woong Cho , SangJun Mo , Hyi-Seung Lee , Jung-Rae Rho , Jongheon Shin; J. Microbiol. 2000;38(3):150-155.

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Abstract: A bioluminescent assay method for detecting the activity of phospholipase C (PLC; phosphatidyl choline cholinephosphohydrolase, EC 3.1.4.3) was developed using bioluminescent marine bacteria. Phospholipase C from Bacillus cereus and sn-1,2-dimyristoyl phosphatidyl choline (DMPC) as a substrate were used in the demonstration, and the produced sn-1,2-dimyristoyl glycerol was further hydrolyzed with lipase from Candida cylidracea. The hydrolyzed myristic acid was quantified using a dark mutant of Vibrio harveyi (designated as M-17). The in vivo light intensity of which was stimulated specifically up to one thousand fold in the presence of myristic acid. The rates of the hydrolysis of the DMPC substrate by the phospholipase measured by the luminescence method were linear with time and the amount of enzyme added. Activity measurement conditions (at 25 C, pH 6.5, 10 min fixed time assay) were established to detect as little as 0.1 mUnit of phospholipase C and 5 nM of myristic acid production.

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