• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.191-195
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• 2011

The measurement and prediction of bacterial transport of bacteria in aquatic systems is of fundamental importance to a variety of fields such as groundwater bioremediation ascending urinary tract infection. The motility of pathogenic bacteria is, however, often missing when considering pathogen translocation prediction. Previously, it was reported that flagellated E. coli can translate upstream under low shear flow conditions. The upstream swimming of flagellated microorganisms depends on hydrodynamic interaction between cell body and surrounding fluid flow. In this study, we used a breathable microfluidic device to image swimming E. coli at a glass surface under low shear flow condition. The tendency of upstream swimming motion was expressed in terms of 'A' value in parabolic equation ($y=Ax^2+Bx+C$). It was observed that high shear flow rate increased the 'A' value as the shear force acting on bacterium increased. Shorter bacterium turned more tightly into the flow as they swim faster and experience less drag force. The result obtained in this study might be relevant in studying the fate and transport of bacterium under low shear flow environment such as irrigation pipe, water distribution system, and urethral catheter.

• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.391-398
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• 2006

$NF-{\kappa}B$ is a transcription factor involved in the innate immunity against bacterial infection and inflammation. It is also known to render cells resistant to the apoptosis caused by some anticancer drugs. Such a chemoresistance of cancer cells may be related to the activation of $NF-{\kappa}B$ transcription factor; however, the mechanism of activation is not well understood. Here, we demonstrate that a chemotherapeutic agent, etoposide, independently stimulates the $I{\kappa}B{\alpha}$ degradation pathway and PI3-kinase/Akt signaling pathway: The classical $I{\kappa}B{\alpha}$ degradation pathway leads to the nuclear translocation and DNA binding of p65 subunit through $IKK{\beta}$ kinase, whereas the PI3-kinase/Akt pathway plays a distinct role in activating this transcription factor. The PI3-kinase/Akt pathway acts on the p50 subunit of the $NF-{\kappa}B$ transcription factor and enhances the DNA binding affinity of the p50 protein. It may also explain the role of the PI3-kinase/Akt pathway in the anti-apoptotic function of $NF-{\kappa}B$ during chemoresistance of cancer cells.

• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.610-615
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• 2017

When Shigella infect host cells, various effecter molecules are delivered into the cytoplasm of the host cell through the type III secretion system (TTSS) to facilitate their invasion process and control the host immune responses. Among these effectors, the S. flexneri effector OspF dephosphorylates mitogen-activated protein kinases and translocates itself to the nucleus, thus preventing histone H3 modification to regulate expression of proinflammatory cytokines. Despite the critical role of OspF, the mechanism by which it localizes in the nucleus has remained to be elucidated. In the present study, we identified a potential small ubiquitin-related modifier (SUMO) modification site within OspF and we demonstrated that Shigella TTSS effector OspF is conjugated with SUMO in the host cell and this modification mediates the nuclear translocation of OspF. Our results show a bacterial virulence factor can exploit host post-translational machinery to execute its intracellular trafficking.

• Journal of Dairy Science and Biotechnology
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• v.27 no.1
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• pp.19-28
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• 2009

Lactoferrin was first identified 60 years ago as a "red protein" in bovine milk. Lactoferrin, one of the transferrin family proteins, is an iron-binding glycoprotein found in milk and various mucosal secretions; it is also released from activated neutrophils. Human lactoferrin has a molecular weight of 82.4 kDa and is composed of 702 or 692 amino acid residues. Bovine lactoferrin has a molecular weight of 83.1 kDa and is composed of 689 amino acid residues. Both lactoferrin and transferrin have the ability to bind two $Fe^{3+}$ ions, together with two ${CO_3}^{2-}$ ions with extremely high affinity; these proteins also have the ability to release this iron at low pH levels. The polypeptide chain in lactoferrin is folded into two globular lobes, representing the N-terminal and C-terminal halves. Both lobes have similar folding and 40% sequence identity. This protein is capable of multiple functions as described in various review papers, including antimicrobial, antiviral, antiinflammatory, anticancer, antioxidant, and cell growth-promoting activities. Lactoferrin also exhibits immunomodulating effects and plays an active role in the regulation of myelopoiesis and the inhibition of bacterial translocation.

• Journal of Microbiology and Biotechnology
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• v.33 no.9
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• pp.1111-1118
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• 2023

As a long-term condition that affects the airways and lungs, chronic obstructive pulmonary disease (COPD) is characterized by inflammation, emphysema, breathlessness, chronic cough, and sputum production. Currently, the bronchodilators and anti-inflammatory drugs prescribed for COPD are mostly off-target, warranting new disease management strategies. Accumulating research has revealed the gut-lung axis to be a bidirectional communication system. Cigarette smoke, a major exacerbating factor in COPD and lung inflammation, affects gut microbiota composition and diversity, causing gut microbiota dysbiosis, a condition that has recently been described in COPD patients and animal models. For this review, we focused on the gut-lung axis, which is influenced by gut microbial metabolites, bacterial translocation, and immune cell modulation. Further, we have summarized the findings of preclinical and clinical studies on the association between gut microbiota and COPD to provide a basis for using gut microbiota in therapeutic strategies against COPD. Our review also proposes that further research on probiotics, prebiotics, short-chain fatty acids, and fecal microbiota transplantation could assist therapeutic approaches targeting the gut microbiota to alleviate COPD.

• Korean Journal of Environmental Agriculture
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• v.33 no.3
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• pp.220-230
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• 2014

BACKGROUND: Excessive metals in the soil have become one of the most significant environmental problems. Phytoremediation has received considerable attention as a method for restoring the contaminated soils. The microbes having remarkable metal tolerance and plant growth-promoting abilities could also play a significant role in remediation of metal-contaminated soils, because bioaugmentation with such microbes could promote phytoextraction of metals. Therefore, the present study was focused on evaluating the phytoextraction of heavy metals (Co, Pb and Zn) in Helianthus annuus (sunflower) induced by bioaugmentation of a phosphate solubilizing bacterium. METHODS AND RESULTS: A phosphate solubilizing bacterium was isolated from metal-contaminated soils based on the greater halo size (>3 mm) with solid NBRIP agar medium containing 10 g glucose, 5 g $Ca_3(PO_4)_2$, 5 g $MgCl_2{\cdot}6H_2O$, 0.25 g $MgSO_4.7H_2O$, 0.2 g KCl, 0.1 g $(NH_4)_2SO_4$ in 1 L distilled water. Isolated bacterial strain was assessed for their resistance to heavy metals; $CoCl_2.6H_2O$, $2PbCO_3.Pb(OH)_2$, and $ZnCl_2$ at various concentrations ranging from $100-400{\mu}g/mL$ (Co, Pb and Zn) using the agar dilution method. A pot experiment was conducted with aqueous solutions of different heavy metals (Co, Pb and Zn) to assess the effect of bacterial strain on growth and metal uptake by Helianthus annuus (sunflower). The impact of bacterial inoculation on the mobility of metals in soil was investigated under laboratory conditions with 50 mL scaled polypropylene centrifuge tubes. The metal contents in the filtrate of plant extracts were determined using an atomic absorption spectrophotometer (Perkinelmer, Aanalyst 800, USA). CONCLUSION: Inoculation with Enterobacter ludwigii PSB 28 resulted in increased shoot and root biomass and enhanced accumulation of Co, Pb and Zn in Helianthus annuus plants. The strain was found to be capable of promoting metal translocation from the roots to the shoots of H. annuus. Therefore, Enterobacter ludwigii PSB 28 could be identified as an effective promoter of phytoextraction of Co, Pb and Zn from metal-contaminated soils.

• Journal of Mushroom
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• v.12 no.3
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• pp.163-170
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• 2014

The potential ability of Button mushroom compost (BMC) to solubilize heavy metals was estimated with metal contaminated soils collected from abandoned mines of Boryeong area in South Korea. The bacterial strains in BMC were isolated for investigating the mobilization of metals in soil or plant by the strains and identified according to 16S rRNA gene sequence analysis. When metal solubilization potential of BMC was assessed in a batch experiment, the BMC was found to be capable of solubilizing metals in the presence of metals (Co, Pb and Zn) and the results showed that inoculation of BMC could increase the concentrations of water soluble Co, Pb and Cd by 35, 25 and 45% respectively, than those of non-inoculated soils. BMC-assisted growth promotion and metal uptake in sunflower (Helianthus annuus) was also evaluated in a pot experiment. In comparison with non-inoculated seedlings, the inoculation led to increase the growth of H. annuus by 27, 25 and 28% respectively in Co, Pb and Zn contaminated soils. Moreover, enhanced accumulation of Co, Pb and Zn in the shoot and root systems was observed in inoculated plants, where metal translocation from root to the above-ground tissues was also found to be enhanced by the BMC. The apparent results suggested that the BMC could effectively be employed in enhancing phytoextraction of Co, Pb and Zn from contaminated soils.

• Biomolecules & Therapeutics
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• v.23 no.6
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• pp.531-538
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• 2015

Preceding infection or inflammation such as bacterial meningitis has been associated with poor outcomes after stroke. Previously, we reported that intracorpus callosum microinjection of lipopolysaccharides (LPS) strongly accelerated the ischemia/reperfusionevoked brain tissue damage via recruiting inflammatory cells into the ischemic lesion. Simvastatin, 3-hydroxy-3-methylgultaryl (HMG)-CoA reductase inhibitor, has been shown to reduce inflammatory responses in vascular diseases. Thus, we investigated whether simvastatin could reduce the LPS-accelerated ischemic injury. Simvastatin (20 mg/kg) was orally administered to rats prior to cerebral ischemic insults (4 times at 72, 48, 25, and 1-h pre-ischemia). LPS was microinjected into rat corpus callosum 1 day before the ischemic injury. Treatment of simvastatin reduced the LPS-accelerated infarct size by 73%, and decreased the ischemia/reperfusion-induced expressions of pro-inflammatory mediators such as iNOS, COX-2 and IL-$1{\beta}$ in LPS-injected rat brains. However, simvastatin did not reduce the infiltration of microglial/macrophageal cells into the LPS-pretreated brain lesion. In vitro migration assay also showed that simvastatin did not inhibit the monocyte chemoattractant protein-1-evoked migration of microglial/macrophageal cells. Instead, simvastatin inhibited the nuclear translocation of NF-${\kappa}B$, a key signaling event in expressions of various proinflammatory mediators, by decreasing the degradation of $I{\kappa}B$. The present results indicate that simvastatin may be beneficial particularly to the accelerated cerebral ischemic injury under inflammatory or infectious conditions.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2004.10a
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• pp.65-67
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• 2004

During initial interactions of bacteria with their host plants, most plants recognize the bacterial infections and repel the pathogen by plant defense mechanism. The most active plant defense mechanism is the hypersensitive response (HR) which is the localized induced cell death in the plant at the site of infection by a pathogen. A primary locus induced in gram-negative phytopathogenic bacteria during this initial interaction is the Hrp locus. The Hrp locus is composed of a cluster of genes that encodes the bacteral Type 111 machinery that is involved in the secretion and translocation of effector proteins to the plant cell. DNA sequence analysis of hrp gene in phytopathogenic bacteria has revealed a Hrp pathogenicity is]and (PAI) with a tripartite mosaic structure. For many gram-negative pathogenic bacteria, colonization of the host's tissue depends on the type III protein secretion system (TTSS) which secrets and translocates effector proteins into the host cell. Effectors can be divided into several groups including broad host range effectors, host specific effectors, disease specific effectors, and effectors inhibit host defenses. The role of effectors carrying LRR domain in plant resistance is very elusive since most known plant resistance gene carry LRR domain. Host specific effectors such as several avr gene products are involved in the determination of the host specificity. Almost all the phytopathogenic Xanthomonas spp. carry avrBs1, avrBs2, and avrBs3 homologs. Some strains of X. oryzae pv. oryzae carry more than 10 copies of avrBs3 homologs. However, the functions of all those avr genes in host specificity are not characterized well.;

• Natural Product Sciences
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• v.10 no.6
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• pp.315-320
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• 2004

Alpha-viniferin was previously isolated as a cyclooxygenase (COX)-2 inhibitor from Carex humilis (Cyperaceae) and is an oligomeric stilbene compound with benzofuran (BF) moieties in its chemical structure. In the present study, a chemically synthetic BF compound, named as 3,3-dimethyl-2,3,4,6,7,8,9,10,11,12,13,14,15,16,17,18-hexadecahydro-1H-benzo[b] cyclopentadeca[d]furan-1-one, was discovered to inhibit bacterial lipo polysaccharide (LPS)-induced prostaglandin $E_2$ $(PGE_2)$ production in macrophages RAW 264.7. The BF compound exhibited a selectively preferred inhibitory effect on COX-2 activity over COX-1 activity. Furthermore, BF compound inhibited LPS-induced COX-2 expression at transcription level. As a down-regulatory mechanism of COX-2 expression shown by BF compound, suppression of nuclear factor $(NF)-{\kappa}B$ activation has been demonstrated. BF compound inhibited LPS-induced $NF-{\kappa}B$ transcriptional activity and nuclear translocation of $NF-{\kappa}B$ p65, in parallel, but did not affect LPS-induced degradation of inhibitory ${\kappa}B{\alpha}$ protein $(I{\kappa}B{\alpha})$. Taken together, anti-inflammatory effect of BF compound on $PGE_2$ production was ascribed by its down-regulatory action on LPS-induced COX-2 synthesis in addition to inhibitory action on enzyme activity of COX-2.