Impact of human activities on changes of ichthyofauna in Dongjin River of Korea in the past 30 years

Ichthyofauna and fish community were investigated at 17 representative stations of the Dongjin River drainage system from spring to fall in 2014. The survey resulted in a list of 53 species belonging to 14 families structured into 4 distinctive parts along the river: uppermost-stream, upper-stream, mid-stream, and lower-stream. Comparison of species lists with 30-year interval exhibited significant decreases in peripheral freshwater fishes, Acheilognathinae, endemic, and indigeneity species, but increases in exotic, epipelagic, and lentic species. Moreover, in the estuary of the Dongjin River drainage system, peripheral freshwater fish species were replaced by pure freshwater fish species due to the Saemangeum sea-wall project. In the upper region of the river, introduced eight alien species from Seomjin River via water diversion tunnels. In the mid-lower region, the construction of floodgates and numerous small weirs caused expansion of lentic water areas, facilitating the spread of problematic exotic species such as Micropterus salmoides, Lepomis macrochirus, and Carassius cuvieri. Also, water deterioration in this region resulted in an increase of tolerant species and a decrease of sensitive and endemic species. Our results suggest that a recovery strategy for a healthy ecosystem in the Dongjin River drainage system should reflect this compartmentalized cause and effect on the changes of icthyofauna.     

Antiviral Effects of Novel Herbal Medicine KIOM-C,on Diverse Viruses

In order to identify new potential antiviral agents, recent studies have advocated thorough testing of herbal medicines or natural substances that are traditionally used to prevent viral infections. Antiviral activities and the mechanism of action of the total aqueous extract preparation of KIOM-C, a novel herbal medicine, against diverse types of viruses were investigated. In vitro antiviral activity against A/Puerto Rico/8/34 (H1N1) (PR8), vesicular stomatitis virus (VSV), and Newcastle disease virus (NDV) through the induction of type-I interferon related protein phosphorylation and up-regulation of pro-inflammatory cytokines in murine macrophage cells (RAW264.7) were determined. In vivo, KIOM-C-treated BALB/c mice showed higher survivability and lower lung viral titers when challenged with A/Aquatic bird/Korea/W81/2005 (H5N2), A/PR/8/34(H1N1), A/Aquatic bird/Korea/W44/2005(H7N3) or A/Chicken/Korea/116 /2004(H9N2) influenza subtypes in contrast with the non-treated group. The present study revealed that total aqueous extract preparation of KIOM-C stimulates an antiviral state in murine macrophage cells and in mice leading to inhibition of viral infection and protection against lethal challenges.     

Stimulation of reductive glycerol metabolism by overexpression of an aldehyde dehydrogenase in a recombinant <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> strain defective in the oxidative pathway

Previously, we constructed a glycerol oxidative pathway-deficient mutant strain of Klebsiella pneumoniae by inactivation of glycerol dehydrogenase (dhaD) to eliminate by-product synthesis during production of 1,3-propanediol (1,3-PD) from glycerol. Although by-product formation was successfully blocked in the resultant strain, the yield of 1,3-PD was not enhanced, probably because dhaD disruption resulted in insufficient regeneration of the cofactor NADH essential for the activity of 1,3-PD oxidoreductase (DhaT). To improve cofactor regeneration, in the present study we overexpressed an NAD⁺-dependent aldehyde dehydrogenase in the recombinant strain. To this end, an aldehyde dehydrogenase AldHk homologous to E. coli AldH but with NAD⁺-dependent propionaldehyde dehydrogenase activity was identified in K. pneumoniae. Functional analysis revealed that the substrate specificity of AldHk embraced various aldehydes including propionaldehyde, and that NAD⁺ was preferred over NADP⁺ as a cofactor. Overexpression of AldHk in the glycerol oxidative pathway-deficient mutant AK/pVOTHk resulted in a 3.6-fold increase (0.57 g l⁻¹ to 2.07 g l⁻¹) in the production of 3-hydroxypropionic acid (3-HP), and a 1.1-fold enhancement (8.43 g l⁻¹ to 9.65 g l⁻¹) of 1,3-PD synthesis, when glycerol was provided as the carbon source, compared to the levels synthesized by the control strain (AK/pVOT). Batch fermentation using AK/pVOTHk showed a significant increase (to 70%, w/w) in conversion of glycerol to the reductive metabolites, 1,3-PD and 3-HP, with no production of by-products except acetate.     

Amphiregulin,an Epidermal Growth Factor Receptor Ligand,Plays an Essential Role in the Pathogenesis of Transforming Growth Factor-β-induced Pulmonary Fibrosis

Dysregulated amphiregulin (AR) expression and EGR receptor (EGFR) activation have been described in animal models of pulmonary fibrosis and in patients with idiopathic pulmonary fibrosis. However, the exact role of AR in the pathogenesis of pulmonary fibrosis has not been clearly defined. Here, we show that a potent profibrogenic cytokine TGF-β1 significantly induced the expression of AR in lung fibroblasts in vitro and in murine lungs in vivo. AR stimulated NIH3T3 fibroblast cell proliferation in a dose-dependent manner. Silencing of AR expression by siRNA or chemical inhibition of EGFR signaling, utilizing AG1478 and gefitinib, significantly reduced the ability of TGF-β1 to stimulate fibroblast proliferation and expression of α-smooth muscle actin, collagen, and other extracellular matrix-associated genes. TGF-β1-stimulated activation of Akt, ERK, and Smad signaling was also significantly inhibited by these interventions. Consistent with these in vitro findings, AR expression was impressively increased in the lungs of TGF-β1 transgenic mice, and either siRNA silencing of AR or chemical inhibition of EGFR signaling significantly reduced TGF-β1-stimulated collagen accumulation in the lung. These studies showed a novel regulatory role for AR in the pathogenesis of TGF-β1-induced pulmonary fibrosis. In addition, these studies suggest that AR, or AR-activated EGFR signaling, is a potential therapeutic target for idiopathic pulmonary fibrosis associated with TGF-β1 activation.     

Identification and utilization of a 1,3-propanediol oxidoreductase isoenzyme for production of 1,3-propanediol from glycerol in Klebsiella pneumoniae

In a previous study, we showed that 1,3-propanediol (1,3-PD) was still produced from glycerol by the Klebsiella pneumoniae mutant strain defective in 1,3-PD oxidoreductase (DhaT), although the production level was lower compared to the parent strain. As a potential candidate for another putative 1,3-PD oxidoreductase, we identified and characterized a homolog of Escherichia coli yqhD (88% homology in amino acid sequence), which encodes an alcohol dehydrogenase and is well known to replace the function of DhaT in E. coli. Introduction of multiple copies of the yqhD homolog restored 1,3-PD production in the mutant K. pneumoniae strain defective in DhaT. In addition, by-product formation was still eliminated in the recombinant strain due to the elimination of the glycerol oxidative pathway. An increase in NADP-dependent 1,3-PD oxidoreductase activity was observed in the recombinant strain harboring multiple copies of the yqhD homolog. The level of 1,3-PD production during batch fermentation in the recombinant strain was comparable to that of the parent strain; further engineering can generate an industrial strain producing 1,3-propanediol.     

Erratum to: Production of isobutanol from crude glycerol by a genetically-engineered Klebsiella pneumoniae strain

Klebsiella pneumoniae was engineered to produce isobutanol from crude glycerol as a sole carbon source by expressing acetolactate synthase (ilvIH), keto-acid reducto-isomerase (ilvC) and dihydroxy-acid dehydratase (ilvD) from K. pneumoniae, and α-ketoisovalerate decarboxylase (kivd) and alcohol dehydrogenase (adhA) from Lactococcus lactis. Engineered K. pneumonia, ?ldhA/pBR-iBO (ilvIH–ilvC–ilvD–kivd–adhA), produced isobutanol (160 mg l^?1) from crude glycerol. To increase the yield of isobutanol, we eliminated the 2,3-butanediol pathway from the recombinant strain by inactivating α-acetolactate decarboxylase (adc). This further engineering step improved the yield of isobutanol from 160 to 320 mg l^?1. This represents the first successful attempt to produce isobutanol from crude glycerol.     

Production of 2-butanol from crude glycerol by a genetically-engineered Klebsiella pneumoniae strain

Klebsiella pneumoniae was engineered to produce 2-butanol from crude glycerol as a sole carbon source by expressing acetolactate synthase (ilvIH), keto-acid reducto-isomerase (ilvC) and dihydroxy-acid dehydratase (ilvD) from K. pneumoniae, and α-ketoisovalerate decarboxylase (kivd) and alcohol dehydrogenase (adhA) from Lactococcus lactis. Engineered K. pneumonia, ?ldhA/pBR-iBO (ilvIH–ilvC–ilvD–kivd–adhA), produced 2-butanol (160 mg l^?1) from crude glycerol. To increase the yield of 2-butanol, we eliminated the 2,3-butanediol pathway from the recombinant strain by inactivating α-acetolactate decarboxylase (adc). This further engineering step improved the yield of 2-butanol from 160 to 320 mg l^?1. This represents the first successful attempt to produce 2-butanol from crude glycerol.