Journal of Microbiology

Journal Articles

Metabolism-mediated induction of zinc tolerance in Brassica rapa by Burkholderia cepacia CS2-1: Sang-Mo Kang , Raheem Shahzad , Saqib Bilal , Abdul Latif Khan , Young-Hyun You , Won-Hee Lee , Hee-La Ryu , Ko-Eun Lee , In-Jung Lee; J. Microbiol. 2017;55(12):955-965. Published online December 7, 2017; DOI: https://doi.org/10.1007/s12275-017-7305-7

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Abstract: Brassica rapa (Chinese cabbage) is an essential component of traditional Korean food. However, the crop is often subject to zinc (Zn+) toxicity from contaminated irrigation water, which, as a result, compromises plant growth and production, as well as the health of human consumers. The present study investigated the bioaccumulation of Zn+ by Burkholderia cepacia CS2-1 and its effect on the heavy metal tolerance of Chinese cabbage. Strain CS2-1 was identified and characterized on the basis of 16S rRNA sequences and phylogenetic analysis. The strain actively produced indole-3-acetic acid (3.08 ± 0.21 μg/ml) and was also able to produce siderophore, solubilize minerals, and tolerate various concentrations of Zn+. The heavy metal tolerance of B. rapa plants was enhanced by CS2-1 inoculation, as indicated by growth attributes, Zn+ uptake, amino acid synthesis, antioxidant levels, and endogenous hormone (ABA and SA) synthesis. Without inoculation, the application of Zn+ negatively affected the growth and physiology of B. rapa plants. However, CS2-1 inoculation improved plant growth, lowered Zn+ uptake, altered both amino acid regulation and levels of flavonoids and phenolics, and significantly decreased levels of superoxide dismutase, endogenous abscisic acid, and salicylic acid. These findings indicate that B. cepacia CS2-1 is suitable for bioremediation against Zn+-induced oxidative stress.

Effect of amikacin on cell wall glycopeptidolipid synthesis in Mycobacterium abscessus: So-Young Lee , Hee-Youn Kim , Byoung-Jun Kim , Hong Kim , Seung-hyeok Seok , Bum-Joon Kim , Yoon-Hoh Kook; J. Microbiol. 2017;55(8):640-647. Published online July 28, 2017; DOI: https://doi.org/10.1007/s12275-017-6503-7

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Abstract: Cultivation of the smooth colony Mycobacterium abscessus at the sub-minimum inhibitory concentration (MIC) of amikacin changed its growth pattern including its colony morphology (smooth to rough) and cell arrangement (dispersed to cord formation). In addition, reduced sliding motility and biofilm formation were observed. The amount of glycogpetidolipid (GPL) and mRNA expression of key genes involved in GPL synthesis were decreased in the amikacin-treated M. abscessus strain. An in vitro infection assay revealed that the amikacin-treated smooth M. abscessus strain induced more pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) than that of the smooth strain in murine macrophage cells. These results suggest that long-term exposure to a low concentration of amikacin causes a physical change in the cell wall which may increase its virulence.

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

Profiling of the Bacteria Responsible for Pyogenic Liver Abscess by 16S rRNA Gene Pyrosequencing: Yun Gyu Song , Sang Gun Shim , Kwang Min Kim , Dong-Hae Lee , Dae-Soo Kim , Sang-Haeng Choi , Jae-Young Song , Hyung-Lyun Kang , Seung-Chul Baik , Woo-Kon Lee , Myung-Je Cho , Kwang-Ho Rhee; J. Microbiol. 2014;52(6):504-509. Published online May 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4241-7

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21 Citations

Abstract: Pyogenic liver abscess (PLA) is a severe disease with considerable mortality and is often polymicrobial. Understanding the pathogens that cause PLA is the basis for PLA treatment. Here, we profiled the bacterial composition in PLA fluid by pyrosequencing the 16S ribosomal RNA (rRNA) gene based on next-generation sequencing (NGS) technology to identify etiological agents of PLA and to provide information of their 16S rRNA sequences for application to DNA-based techniques in the hospital. Twenty patients with PLA who underwent percutaneous catheter drainage, abscess culture, and blood culture for isolates were included. Genomic DNAs from abscess fluids were subjected to polymerase chain reaction and pyrosequencing of the 16S rRNA gene with a 454 GS Junior System. The abscess and blood cultures were positive in nine (45%) and four (20%) patients, respectively. Pyrosequencing of 16S rRNA gene showed that 90% of the PLA fluid samples contained single or multiple genera of known bacteria such as Klebsiella, Fusobacterium, Streptococcus, Bacteroides, Prevotella, Peptostreptococcus, unassigned Enterobacteriaceae, and Dialister. Klebsiella was predominantly found in the PLA fluid samples. All samples that carried unassigned bacteria had 26.8% reads on average. We demonstrated that the occurrence of PLA was associated with eight known bacterial genera as well as unassigned bacteria and that 16S rRNA gene sequencing was more useful than conventional culture methods for accurate identification of bacterial pathogens from PLA.

Comparative Analysis of Immune Responses to Mycobacterium abscessus Infection and Its Antigens in Two Murine Models: Bo-Young Jeon , Jeongyeon Kwak , Seung-Sub Lee , SangNae Cho , Chul Jae Won , Jin Man Kim , Sung Jae Shin; J. Microbiol. 2009;47(5):633-640. Published online October 24, 2009; DOI: https://doi.org/10.1007/s12275-009-0139-1

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Abstract: Mycobacterium abscessus has been identified as an emerging pulmonary pathogen in humans. Because little is known regarding immune responses elicited by M. abscessus or its antigens, immunological responses were studied in two murine models subjected to intravenous (high-dose or systemic infection) or pulmonary (low-dose or local infection) inoculation with M. abscessus ATCC 19977. An overall comparison between the two models showed similar patterns of bacterial survival and host immune responses. The colonization of M. abscessus was the highest at 5 days post-infection (dpi) and its elimination was positively correlated with cell-mediated immunity in both challenges. However, an inverse relationship was observed between progressive inflammation and mycobacterial colonization levels in mice infected with a high dose at 14 dpi. Regarding antigens, culture filtrate (CF) of M. abscessus strongly induced IFN-γ secretion, whereas cellular extract (CE) antigen elicited strong antibody responses. The antibody response to M. abscessus antigens in mice subjected to low-dose infection increased when the cellular immune response decreased over 14 dpi. However, the antibody response for the high-dose infection increased promptly after the infection. In comparison of cytokine expression in lung homogenates after M. abscessus infection, Th1 and Th2 cytokines increased simultaneously in the high-dose infection, whereas only cell-mediated immunity developed in the low-dose pulmonary infection. These findings not only enhance our understanding of the immune response to M. abscessus infection according to systemic or pulmonary infection, but may also aid in immunological diagnosis and vaccine development.

Production of and Applications for a Polyclonal IgY Diagnostic Reagent Specific for Mycobacterium avium subsp. paratuberculosis: Sung Jae Shin , Seung-Sub Lee , Elizabeth J. B. Manning , Michael T. Collins; J. Microbiol. 2009;47(5):600-609. Published online October 24, 2009; DOI: https://doi.org/10.1007/s12275-009-0052-7

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Abstract: Antibodies specific to the cell surface antigens of Mycobacterium avium subsp. paratuberculosis (MAP) have multiple useful applications, e.g. organism detection, immunoconcentration, and cell visualization. The aim of this study was to produce and compare polyclonal antibodies for such research and diagnostic purposes. Three polyclonal antibodies to MAP were produced using sera from immunized rabbits and chickens plus naturally infected cows. Cross-reactive antibodies in each MAP antibody preparation were removed by absorption with heterologous mycobacterial and non-mycobacterial cells. The specificity of each resulting polyclonal antibody preparation was evaluated by ELISA to multiple bacterial cell wall extract antigens. After absorption, chicken anti-MAP IgY had the highest specificity of the three antibody preparations. FITC-labeled anti-MAP IgY was used to effectively locate MAP in macrophages 12 h post-infection. Also, immuno- magnetic beads coated with anti-MAP IgY enhanced recovery of MAP from bacterial suspensions in comparison with non-antibody coated beads. Anti-MAP IgY provides a novel new reagent with broad diagnostic and research applications requiring specific concentration, detection, and quantification of MAP.

Isolation and Characterization of a Marine Algicidal Bacterium against the Harmful Raphidophyceae Chattonella marina: Yun Sook Kim , Dae-Sung Lee , Seong-Yun Jeong , Won Jae Lee , Myung-Suk Lee; J. Microbiol. 2009;47(1):9-18. Published online February 20, 2009; DOI: https://doi.org/10.1007/s12275-008-0141-z

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94 Citations

Abstract: A bacterial strain named AB-4 showing algicidal activity against Chattonella marina was isolated from coastal water of Uljin, Republic of Korea. The isolated strain was identified as Bacillus sp. by culture morphology, biochemical reactions, and homology research based on 16S rDNA. The bacterial culture led to the lysis of algal cells, suggesting that the isolated strain produced a latent algal-lytic compound. Amongst changes in algicidal activity by different culture filtrate volumes, the 10% (100 ?/ml) concentration showed the biggest change in algicidal activity; there, estimated algicidal activity was 95%. The swimming movements of Chattonella marina cells were inhibited because of treatment of the bacterial culture; subsequently, Chattonella marina cells became swollen and rounded. With longer exposure time, algal cells were disrupted and cellular components lost their integrity and decomposed. The released algicide(s) were heat-tolerant and stable in pH variations, except pH 3, 4, and 5. Culture filtrate of Bacillus sp. AB-4 was toxic against harmful algae bloom (HAB) species and nontoxic against livefood organisms. Bacillus sp. AB-4 showed comparatively strong activity against Akashiwo sanguinea, Fibriocapsa japonica, Heterosigma akashiwo, and Scrippsiella trochoidea. These results suggest that the algicidal activity of Bacillus sp. AB-4 is potentially useful for controlling outbreaks of Chattonella marina.

Isolation and characterization of the Phenotypic Revertants of Streptomyces coelicolor abs Mutant: Jung, Ho Sun , Park, Uhn Mee; J. Microbiol. 1997;35(4):271-276.

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Abstract: We isolated phenotypic suppressors of an absB (antibiotics synthesis suppression) strain. In the absB colonies, all four antibiotics including two pigmented antibiotics were blocked so that no pigmentation could be found. We assumed that in the colonies with the wuppressive(or reversive) mutation, both pigmentation would be restored so that the strains with suppressive mutation could be cisually detected. Harvested absB spores were treated with chemical mutagen along with electric shock, and were spread on specially fromulated minimal medium plates. The pigmented colonies were isolated from the unpigmented majorities. In one candidate strain, the restoration and significant overproduction of actinorhodin and undecylprodigiosin were recognized. In three other candidate strains, the overproduction of actinorhodin and restoraion of undecylprodigiosin were observed. The production of the two unpigmented antibiotics (CDA and methylenomycin) were visualized in the tested candidate strains. The strains with wuppressive mutations would be very useful in dlucidating the regulation network of antiviotics synthesis and overproduction of the antibiotics.

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