• Korean Journal of Environmental Agriculture
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• v.6 no.2
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• pp.94-100
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• 1987

Plant mitochondria, irradiated with blue-colored $sunlight(350{\sim}500nm)$ under aerobic and anaerobic conditions, were assayed as to the electron transfer activity of respiratory enzyme system, and compared with those irradiated with orange-colored light(white sunlight minus blue-colored light). The respiratory activity of mitochondria was most seriousely inhibited by illumination with blue-colored light under aerobic condition. Deaeration of mitochondrial suspension resulted in substantial decrease of the photoinhibition by blue-colored light. Meanwhile, orange-colored light demonstrated much less effectiveness-almost ineffectiveness-in causing the inhibition of mitochondrial respiration system. The results of enzymatic assay revealed a strong possibility that FMN in NDH and heme group at least in cytochrome c oxidase, but not FAD in SDH, are the photodynamic sensitizers in mitochondrial inner membrane. Also worthwhile to note is the significant difference from the others of SDH in its photoinhibitory response to the light quality of visible light; that the inhibition of SDH by irradiation was not affected by atmospheric condition and that orange-colored light gave rise to considerable extents of inhibition to the enzyme. This observation was tentatively interpreted in terms of photosensitized reaction not involving molecular oxygen possibly catalyzed by Fe-S centers in the enzyme. The superoxide production and the membrane peroxidation of mitochondria under various treatments also indicated that there was blue-light photodynamic reaction in mitochondria involving active oxygens.

• The Korean Journal of Mycology
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• v.10 no.3
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• pp.119-124
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• 1982

The characteristics of the six different agricultural soil from Michigan were as follows. Colwood and Capac soil were loam, Gilford and Ceresco were sandy clay loam, Sission was clay loam, and Spinks was sandy loam. pH of Gilford sandy clay loam was 6.6 whereas that of the soil ranged $5.4{\sim}5.9$. Gilford sandy loam found to contain a relatively higher amount of organic matters as compared to other soils. Furthermore, the numbers of bacteria in Gilford sandy clay loam were significantly higher than those in other soils. The populations of fungi in Gilford sandy clay loam and Colwood loam soils were significantly greater than those in other soils. On the other hand, the densities of actinomycetes in Gilford sandy clay loam and Ceresco sandy clay loam soils were significantly different from those in other soils. The population of anaerobic bacteria varied depending on the soils; Ceresco sandy clay loam, Capac loam, Colwood loam soils have higher numbers of bacteria, whereas Gilford sandy clay loam was very lesser than the other soils. In the $^{14}C-glucose$ respiration by soil microorganisms after 10 hrs, the respiration rate was decreasing in the order of Ceresco sandy clay loam, Spinks sandy loam, Colwood loam, Sission clay loam, Capac loam and Gilford sandy clay loam. Germination of test propagules on natural soil soil was $0{\sim}5%$, and it was germinated $90{\sim}98%$ on autoclaved soil and PDA. The propagules differed in thier germination response to nutrients added to the soils. In general, more nutrients were required to promote germination on Capac loam and Gilford sandy loam soil than Spinks sandy loam soil. Especially Mortierella n. sp. required more nutrients for germination to obtain the same ratio as Helminthosporium victoriae.

• Journal of Wetlands Research
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• v.9 no.1
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• pp.1-11
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• 2007

The objectives of this study are: (1) to compare the rates and pathways of organic matter minerlaization at stagnant freshwater wetland in Shiwha to highly irrigated coastal wetland in Ganghwa; and (2) to discuss the significance of irrigation into the sediment in controlling the organic carbon oxidation in Shiwha wetland. Concentrations of $CO_2$, $NH_4{^+}$ and $H_2S$ in the pore water of the Shiwha wetland were 3 times, 30 times, and 3 times higher than that in the pore water of the Ganghwa wetland, respectively. The ratio of Fe(III) to total reduced sulfur at the Ganghwa wetland was 12 times higher than at the Shiwha wetland. The results indicated that the Ganghwa wetland with frequent tidal inundation were relatively oxidized than highly stagnant Shiwha wetland. Rates of organic matter oxidation at the Ganghwa wetland ($0.039mM\;C\;h{-1}$) was 390 times higher than that at the Shiwha wetland ($0.0001mM\;C\;h{-1}$). Rates of sulfate reduction at the Shiwha wetland ($314{\sim}580nmol\;cm^{-3}\;d{-1}$) were comparable to the sulfate reduction at Ganghwa wetland ($2{\sim}769nmol\;cm^{-3}\; d{-1}$), whereas Fe(III) reduction rates were 1.7 times higher at the Ganghwa wetland ($0.1368{\mu}mol\;cm^{-3}\;d{-1}$) than at the Shiwha wetland ($0.087{\mu}mol\;cm^{-3}\;d{-1}$). The results implied that the water flow system of the Shiwha wetland was too stagnant to flush out the reduced pore water from the sediment, and thus anaerobic microbial respiration was limited by the availability of electron acceptors.

• Economic and Environmental Geology
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• v.45 no.2
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• pp.105-119
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• 2012

Indigenous bacteria isolated from contaminated sites play important roles to remediate contaminated groundwater. Chromium has the most stable oxidation states. Cr(VI) is toxic, carcinogenic, and mobile, but Cr(III) is less toxic and immobile. In this study, indigenous microorganism (MMPH-0) was enriched from Cr(VI) contaminated groundwater, and identified by 16S rRNA gene analysis. Using MMPH-0, the effect of stimulating with e-donors (glucose, lactate, acetate, and no e-donor control), respiration conditions, biomass, tolerance, and geochemical changes on Cr(VI) reduction were investigated in batch experiments for 4 weeks. The changes of Cr(VI) concentration and geochemical conditions were monitored using UV-vis-spectrophotometer and Eh-pH meter. And the morphological and chemical characteristics of MMPH-0 and precipitates in the effluents were characterized by TEM-EDS and SEM-EDS analyses. MMPH-0 (Enterobacter aerogenes) was able to tolerate up to 2000 mg/L Cr(VI) and reduce Cr(VI) under aerobic and anaerobic conditions. MMPH-0 performed faster and higher efficiency of Cr(VI) reduction with electron donors (over 70% after 1 week with e-donor, 10-20% after 4 weeks without e-donor). The changes of Eh-pH in effluents showing the tendency from oxidizing to reducing condition and a bit of acidic change in pH due to microbial oxidation of organic matters donating electrons and protons suggested the roles of MMPH-0 on Cr(VI) in the contaminated water catalyzing to transit geochemical stable zone for more stable $Cr(OH)_3$ or Cr(III) precipitates. TEM/SEM-EDS analyses of MMPH-0 and precipitates indicate direct and indirect Cr(VI) reduction: extracellular polymers capturing Cr component outside cells. These results suggested diverse indigenous bacteria and their biogeochemical reactions might enhance more effective and feasible remediation technology of redox sensitive heavy metals in metal-contaminated in groundwater.