Journal of Microbiology

Journal Articles

Silver Nanoparticles Modified with Polygonatum sibiricum Polysaccharide Improve Biocompatibility and Infected Wound Bacteriostasis: Ruonan Wang , Rongyu Li , Peng Zheng , Zicheng Yang , Cheng Qian , Zhou Wang , Senhe Qian; J. Microbiol. 2023;61(5):543-558. Published online April 13, 2023; DOI: https://doi.org/10.1007/s12275-023-00042-8

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Abstract: Silver nanoparticles (AgNPs) exhibit strong antibacterial activity and do not easily induce drug resistance; however, the poor stability and biocompatibility in solution limit their widespread application. In this study, AgNPs were modified with Polygonatum sibiricum Polysaccharide (PSP) to synthesize PSP@AgNPs with good stability, biocompatibility, and antibacterial activity. When PSP@AgNP synthesis was performed under a reaction time of 70 min, a reaction temperature of 35 °C, and an AgNO3- to-PSP volume ratio of 1:1, the synthesized PSP@AgNPs were more regular and uniform than AgNPs, and their particle size was around 10 nm. PSP@AgNPs exhibited lower cytotoxicity and hemolysis, and stronger bacteriostatic activity. PSP@AgNPs damage the integrity and internal structure of cells, resulting in the leakage of intracellular nucleic acids and proteins. The rate of cell membrane damage in Escherichia coli and Staphylococcus aureus treated with PSP@ AgNPs increased by 38.52% and 43.75%, respectively, compared with that of AgNPs. PSP@AgNPs inhibit the activities of key enzymes related to antioxidant, energy and substance metabolism in cells. The inhibitory effects on the activities of superoxide dismutase (SOD), catalase (CAT), adenosine triphosphate enzyme (ATPase), malate dehydrogenase (MDH), and succinate dehydrogenase (SDH) in E. coli and S. aureus cells were significantly higher than those of AgNPs. In addition, compared with AgNPs, PSP@AgNPs promote faster healing of infected wounds. Therefore, PSP@AgNPs represent potential antibacterial agents against wound infections.

Antibiofilm effect of biofilm-dispersing agents on clinical isolates of Pseudomonas aeruginosa with various biofilm structures: Soo-Kyoung Kim , Xi-Hui Li , Hyeon-Ji Hwang , Joon-Hee Lee; J. Microbiol. 2018;56(12):902-909. Published online October 25, 2018; DOI: https://doi.org/10.1007/s12275-018-8336-4

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Abstract: Pseudomonas aeruginosa, an opportunistic human pathogen, causes many biofilm-mediated chronic infections. In this study, biofilm structures of various clinical strains of P. aeruginosa isolated from hospitalized patients were examined and their influence on the biofilm-dispersing effects of chemicals was investigated. The clinical isolates formed structurally distinct biofilms that could be classified into three different groups: 1) mushroom-like, 2) thin flat, and 3) thick flat structures. A dispersion of these differently structured biofilms was induced using two biofilm-dispersing agents, anthranilate and sodium nitroprusside (SNP). Although both SNP and anthranilate could disperse all types of biofilms, the thick flat biofilms were dispersed less efficiently than the biofilms of other structures. This suggests that biofilm-dispersing agents have higher potency on the biofilms of porous structures than on densely packed biofilms.

A murine colitis model developed using a combination of dextran sulfate sodium and Citrobacter rodentium: Jin-Il Park , Sun-Min Seo , Jong-Hyung Park , Hee-Yeon Jeon , Jun-Young Kim , Seung-Hyun Ryu , Yang-Kyu Choi; J. Microbiol. 2018;56(4):272-279. Published online April 2, 2018; DOI: https://doi.org/10.1007/s12275-018-7504-x

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Abstract: Adult mice were treated with dextran sulfate sodium (DSS) and infected with Citrobacter rodentium for developing a novel murine colitis model. C57BL/6N mice (7-week-old) were divided into four groups. Each group composed of control, dextran sodium sulfate-treated (DSS), C. rodentiuminfected (CT), and DSS-treated and C. rodentium-infected (DSS-CT) mice. The DSS group was administered 1% DSS in drinking water for 7 days. The CT group was supplied with normal drinking water for 7 days and subsequently infected with C. rodentium via oral gavage. The DSS-CT group was supplied with 1% DSS in drinking water for 7 days and subsequently infected with C. rodentium via oral gavage. The mice were sacrificed 10 days after the induction of C. rodentium infection. The DSS-CT group displayed significantly shorter colon length, higher spleen to body weight ratio, and higher histopathological score compared to the other three groups. The mRNA expression levels of tumor necrosis factor (TNF)-α and interferon (INF)-γ were significantly upregulated; however, those of interleukin (IL)-6 and IL-10 were significantly downregulated in the DSS-CT group than in the control group. These results demonstrated that a combination of low DSS concentration (1%) and C. rodentium infection could effectively induce inflammatory bowel disease (IBD) in mice. This may potentially be used as a novel IBD model, in which colitis is induced in mice by the combination of a chemical and a pathogen.

A lactic acid bacterium isolated from kimchi ameliorates intestinal inflammation in DSS-induced colitis: Jin-Soo Park , Inseong Joe , Paul Dong Rhee , Choon-Soo Jeong , Gajin Jeong; J. Microbiol. 2017;55(4):304-310. Published online January 26, 2017; DOI: https://doi.org/10.1007/s12275-017-6447-y

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Abstract: Some species of lactic acid bacteria have been shown to be beneficial in inflammatory bowel disease (IBD). In the pre-sent study, a strain of lactic acid bacterium (Lactobacillus paracasei LS2) was isolated from the Korean food, kimchi, and was shown to inhibit the development of experimental colitis induced by dextran sulfate sodium (DSS). To inves-tigate the role of LS2 in IBD, mice were fed DSS in drinking water for seven days along with LS2 bacteria which were administered intragastrically to some of the mice, while phos-phate-buffered saline (PBS) was administered to others (the controls). The administration of LS2 reduced body weight loss and increased survival, and disease activity indexes (DAI) and histological scores indicated that the severity of colitis was significantly reduced. The production of inflammatory cy-tokines and myeloperoxidase (MPO) activity also decreased. Flow cytometry analysis showed that the number of Th1 (IFN-γ) population cells was significantly reduced in the LS2- administered mice compared with the controls. The admini-stration of LS2 induced the increase of CD4+FOXP3+ Treg cells, which are responsible for IL-10. Numbers of macro-phages (CD11b+ F4/80+), and neutrophils (CD11b+ Gr-1+) among lamina propria lymphocytes (LPL) were also reduced. These results indicate that LS2 has an anti-inflammatory effect and ameliorates DSS-induced colitis.

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

Molecular Cloning, Purification, and Characterization of a Superoxide Dismutase from a Fast-Growing Mycobacterium sp. Strain JC1 DSM 3803: Ji-Sun Nam , Jee-Hyun Yoon , Hyun-Il Lee , Si Wouk Kim , Young-Tae Ro; J. Microbiol. 2011;49(3):399-406. Published online June 30, 2011; DOI: https://doi.org/10.1007/s12275-011-1046-9

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Abstract: A cytosolic superoxide dismutase (SOD) was purified and characterized from a fast-growing Mycobacterium sp. strain JC1 DSM 3803 grown on methanol. The native molecular weight of the purified SOD was estimated to be 48 kDa. SDS-PAGE revealed a subunit of 23 kDa, indicating that the enzyme is a homodimer. The enzyme activity was inhibited by H2O2 and azide. The purified SOD contained 1.12 and 0.56 g-atom of Mn and Fe per mol of enzyme, respectively, suggesting that it may be a Fe/Mn cambialistic SOD. The apo-SOD reconstitution study revealed that Mn salts were more specific than Fe salts in the SOD activity. The gene encoding the SOD was identified from the JC1 cosmid genomic library by PCR screening protocol. The cloned gene, sodA, had an open reading frame (ORF) of 624 nt, encoding a protein with a calculated molecular weight of 22,930 Da and pI of 5.33. The deduced SodA sequence exhibited 97.6% identity with that of Mycobacterium fortuitum Mn-SOD and clustered with other mycobacterial Mn-SODs. A webtool analysis on the basis of SOD sequence and structure homologies predicted the SOD as a tetrameric Mn-SOD, suggesting that the protein is a dimeric Mn-SOD having tetramer-specific sequence and structure characteristics.

Molecular Cloning, Purification, and Characterization of a Novel, Acidic, pH-Stable Endoglucanase from Martelella mediterranea: Junli Dong , Yuzhi Hong , Zongze Shao , Ziduo Liu; J. Microbiol. 2010;48(3):393-398. Published online June 23, 2010; DOI: https://doi.org/10.1007/s12275-010-9361-0

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31 Citations

Abstract: A novel gene encoding an endoglucanase designated Cel5D was cloned from a marine bacterium Martelella mediterranea by genomic library. The gene had a 1,113 bp opening reading frame encoding a 371-amino-acid protein with a molecular mass of 40,508 Da and containing a putative signal peptide (41 amino acids). Cel5D had low similarity (48-51% identity) with other known endoglucanases and consisted of one single catalytic domain, which belonged to the glycosyl hydrolase family 5. The maximum activity of Cel5D was observed at 60°C and pH 5.0. Cel5D displayed broad pH stability within the range of pH 3.0-11.0 and retained hydrolytic activity in the presence of a wide variety of metal ions and some chemical reagents. These characteristics suggest that the enzyme has considerable potential in industrial applications.

Iso-Superoxide Dismutase in Deinococcus grandis, a UV Resistant Bacterium: Na-Rae Yun , Young Nam Lee; J. Microbiol. 2009;47(2):172-177. Published online May 2, 2009; DOI: https://doi.org/10.1007/s12275-008-0221-0

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Abstract: Deinococcus grandis possesses two types of superoxide dismutase (SOD, E. C. 1.15.1.1.) that show distinct electrophoretic behavior, one that migrates slowly and the other that migrates rapidly (SOD-1 and SOD-2, respectively). In this study, SOD-1 was uniformly and abundantly detected, regardless of growth phase, whereas SOD-2 was not detected during early growth, but was detectable from the exponential growth phase. In addition, a substantial increase in SOD-2 was observed in cells that were treated with potassium superoxide or UV, which suggests that SOD-2 is an inducible protein produced in response to stressful environments. Insensitivity of SOD-1 to both H2O2 and cyanide treatment suggests that SOD-1 is MnSOD. However, SOD-2 would be FeSOD, since it lost activity in response to H2O2 treatment, but not to cyanide. Localization studies of D. grandis iso-SODs in sucrose-shocked cells suggest that SOD-1 is a membrane-associated enzyme, whereas SOD-2 is a cytosolic enzyme. In conclusion, SOD-1 seems to be an essential constitutive enzyme for viability and SOD-2 appears to be an inducible enzyme that is probably critical for survival upon UV irradiation and oxidative stress.

Cloning, Expression, and Characterization of Thermostable Manganese Superoxide Dismutase from Thermoascus aurantiacus var. levisporus: Ning-Ning Song , Yan Zheng , Shi-Jin E , Duo-Chuan Li; J. Microbiol. 2009;47(1):123-130. Published online February 20, 2009; DOI: https://doi.org/10.1007/s12275-008-0217-9

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Abstract: A superoxide dismutase (SOD) gene of Thermoascus aurantiacus var. levisporus, a thermophilic fungus, was cloned, sequenced, and expressed in Pichia pastoris and its gene product was characterized. The coding sequence predicted a 231 residues protein with a unique 35 amino acids extension at the N-terminus indicating a mitochondrial-targeting sequence. The content of Mn was 2.46 ug/mg of protein and Fe was not detected in the purified enzyme. The enzyme was found to be inhibited by NaN3, but not by KCN or H2O2. These results suggested that the SOD in Thermoascus aurantiacus var. levisporus was the manganese superoxide dismutase type. In comparison with other MnSODs, all manganese-binding sites were also conserved in the sequence (H88, H136, D222, H226). The molecular mass of a single band of the enzyme was estimated to be 21.7 kDa. The protein was expressed in tetramer form with molecular weight of 68.0 kDa. The activity of purified protein was 2,324 U/mg. The optimum temperature of the enzyme was 55oC and it exhibited maximal activity at pH 7.5. The enzyme was thermostable at 50 and 60oC and the half-life at 80oC was approximately 40 min.

Journal Article

In vitro Activity of Sodium Benzoate Against Clinically Relevant Enterococcus faecalis and Enterococcus faecium Isolates: Oguz Karabay , Esra Kocoglu , Nevin Ince , Tufan Sahan , Davut Ozdemir; J. Microbiol. 2006;44(1):129-131.; DOI: https://doi.org/2325 [pii]

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Abstract: The antimicrobial effects of sodium benzoate against Enterococcus faecalis and Enterococcus faecium were investigated. The MIC90 of sodium benzoate were 64 mg/L for E. faecalis and 32 mg/L for E. faecium, while the MBC90 were 128 mg/L and 64mg/L, respectively. Although further studies are required for clinical evidence, sodium benzoate seems to be effective against Enterococcus spp.

Increased Activities of SOD and Catalase on Aerobic Growth in Arcobacter nitrofigilis: Park, Young Bok , han, Yeong Hwan; J. Microbiol. 1997;35(3):239-240.

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Abstract: A free-living nitrogen fixing Arcobacter nitrofigilis exhibuted the typical characteristics of aerobic growth in which the maximal cell growth was shown under an ambient air atmospjere, whereas no cell growth was shown umder an anaerobic condition. When oxygen concentration was increased, the activities of SOD and catalase were increased. These suggest that the aerobic nature of A. nitrofigilis might be due to the increased levels of both enzymes that scavenge toxic forms of oxygen.

Molecular Cloning and Characterization of Mn-Superoxide Dismutase Gene from Candida sp.: Hong, Yun Mi , Nam, Yong Sik , Choi, Soon Yong; J. Microbiol. 1997;35(4):309-314.

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Abstract: The manganese-containing superoxide dismutase (MnSOD) is a major component of the cellular defence mechanisms against the toxic effects of the superoxide radical. Within the framework of studies on oxidative stress=responsible enzymes in the Candida sp., the gene encoding the MnSOD was isolated and examined in this study. A specific primer was designed based on conserved regions of MnSOD sequences from other organisms, and was used to isolate the gene by PCR on reverse-transcribed Candida poly(A^+) RNA. The PCR product was used to screen a Candida genomic lambda library and the nucleotide wequence of positive clone was determined. The deduced primary sequence encodes a 25kDa protein which has the conserved residues for enzyme activity and metal binding. The 28 N-terminal amino acids encoded by the Candida cDNA comprise a putatice mitochondrial transit peptide. Potential regulatory elements were identified in the 5' flanking sequences. Northern blot analysis showed that the transcription of the MnSOD gene is induced 5-to 10-fold in response to mercury, cadmium ions and hydrogen peroxide.

Response of CuZnSOD and HP1 conjugated gene in Escherichia coli double mutants to oxidative stress: Park, Hye Young , Kim, Young Gon; J. Microbiol. 1998;36(3):171-178.

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Abstract: In Escherichia coli, the counterbalances between superoxide dismutase (SOD) and hydroperoxidase are more important for overall sensitivity to oxidative stress such as paraquat (PQ, 0.1 mM), H_2O_2 (1mM), CuSO_4(0.1 mM), CuSO_4 and heat shock (37℃→42℃) than the level of either SOD or HP1 alone. To evaluate the relative coordinate defense, E. coli SOD and/or hydroperoxidase double mutants were transformed with plasmids expressing SOD^+HP1^-, SOD^-HP1^+ and SOD^-HP1^-, and their physiological response to oxidative stess was measured. SOD was found to be more important than hydroperoxide in preventing oxygen-mediated stress except for the case of H_2O_2 treatment in the presence of SOD. Nevertheless, a balance between both enzymes are necessary for an effective defense against oxygen mediated radicals. The average ratio of SOD:HP1 on activity of various E. coli strains under oxidative stress except copper sulphate treatment show about 1.4 in the wild type. When the ratio, however, was reversed in mutant cells encoded with Photobactrium leiognathi CuZnSOD gene, their sensitivities were more increased. This suggests that although HP1 could reduce the H_2O_2 or hydroxyl radicals, it also inhibited the SOD function against ixygen radicals.

Superoxide Dismutase Profiles in the Mesophilic Deinococcus Species: Young Sun Yun , Young Nam Lee; J. Microbiol. 2001;39(3):232-235.

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Abstract: Electrophoretic resolution of superoxide dismutase (SOD) from the highly UV-resistant bacteria, Deinococcus species revealed multiple forms of superoxide dismutases (SODs) in D. radiodurans, D. grandis, and D. proteolyticus, as judged from electrophoretic properties and metal cofactors. A single SOD occurred in both D. radiophilus and D. radiopugnans. Deinococcal SODs were either MnSOD, FeSOD or cambialistic Mn/FeSOD. The unique SOD profile of each mesophilic Deinococcus species, multiplicity and metal cofactors, would be valuable in identifying Deinococcus species.

Isolation and Characterization of the sod2+ Gene Encoding a Putative Mitochondrial Manganese Superoxide Dismutase in Schizosaccharomyces pombe: Jae-Hoon Jeong , Eun-Soo Kwon , Jung-Hye Roe; J. Microbiol. 2001;39(1):37-41.

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Abstract: The fission yeast Schizosaccharomyces pombe contains two distinct superoxide dismutase (SOD) activities, one in the cytosol encoded by the sod1+ gene and the other in mitochondria. The sod2+ gene encoding putative mitochondrial manganese superoxide dismutase (MnSOD) was isolated from the S. pombe genomic library using a PCR fragment as the probe. The nucleotide sequence of the sod2+ gene and its flanking region (4051 bp HindIII fragment) was determined. An intron of 123 nt in size was predicted and confirmed by sequencing the cDNA following reverse transcription PCR. The predicted Sod2p consists of 218 amino acid residues with a molecular mass of 24,346 Da. The deduced amino acid sequence showed a high degree of homology with other MnSODs, especially in the metal binding residues at the active site and their relative positions. The transcriptional start site was mapped by primer extension at 231 nt upstream from the ATG codon. A putative TATA box (TATAAAA) was located 58 nt upstream from the transcriptional start site and putative polyadenylation sites were located at 1000, 1062, and 1074 nt downstream from the ATG start codon.

Examination of the Antioxidant Potential of Pycnogenol under Conditions of Oxidative Stress in Escherichia coli Mutants Deficient in HP1 and Superoxide Dismutase Activities: Jeong A Youm , Young Gon Kim; J. Microbiol. 2003;41(1):28-33.

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Abstract: Pycnogenol (PYC) is believed to have potential as a therapeutic agent against free radical-mediated oxidative stress. It is important, therefore, to understand the interactions between PYC and cellular defenses against oxidative stress. Toward this end, we analyzed the survival rates on the gene expression responses of E. coli sod katG mutants to PYC after pre-treatment of PQ or H_2O_2-mediated stress under aerobic conditions. We identified SOD induced by PYC, but not HP1 in sod katG mutants. A striking result was the PYC induction of SOD with antioxidant property in single katG mutant cells, particularly MnSOD and CuZnSOD. These inductions were further increased with oxidative stress, while HP1 was not induced in these conditions. The effects of pycnogenol treatment on these cells depend in part on its concentration on the stress response. Protective effects of PYC exposure which affected gene expression in cells were consistent with cell survival rates. Our results demonstrate that pycnogenol may alter the stress response gene expression in a specific manner such as SoxRS because PYC induction of single mutant only worked under increased PQ stress. All together our data indicate that SOD activity is essential for the cellular defense against PQ-mediated oxidative stress, suggesting that PYC may not be effective as an antioxidant in only oxidative stress conditions. On the other hand, it was expected that PYC may play a role as a pro-oxidant and if it is available for use, it should be evaluated carefully.

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