Environmental Sciences Bulletin of The Korean Environmental Sciences Society
The Korean Environmental Sciences Society
- Monthly
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- 1226-6957(pISSN)
Volume 1 Issue 2
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Effects of light on leaf senescence of Phaseolus vulgaris were investigated by measuring the disassembly of chlorophyll-protein complexes in detached leaves which had been kept in the dark or under light. The loss of chlorophyll accompanied by degradation of chlorophyll-protein complexes. PSI (photosystem I) complex containing LHCI (light harvesting complex of PSI) apoproteins was rapidly decreased after the early stage of dark-induced senescence. RC(reaction center)-Core3 was slightly increased until 4 d and slowly decreased thereafter. As disassembly of LHCII trimer progressed after the late stage of senescence, there was a steady increase in the relative amount of SC(small complex)-2 containing LHCII monomer. On the other hand, white and red light adaptation caused the structural stability of chlorophyll-protein complexes during dark-induced senescence. Particularly, red light was more effective in the retardation of LHCII breakdown than white light, whereas white light was slightly effect in protecting the disassembly of PSI complex compared to red light. These results suggest, therefore, that light may be a regulatory factor for stability of chlorophyll-protein complexes in the senescent leaves.
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The amounts of ascorbic acid in chloroplasts treated with light and light+paraquat (PQ) were reduced by 81 and
$82\%$ of initial level, respectively at 24 hr at incubation. And those treated with dark and dark+PQ were decreased by 46 and$55\%$ of the original level, respectively. Malondialdehyde (MDA) contents at 24 hr of dark and dark+PQ treatment were increased by 6 and$31\%$ of the initial level, respectively. When chloroplasts were treated with light and light+PQ, MDA contents after 24 hr were increased by 88 and$146\%$ of the initial level, respectively. SOD activities treated with light and light+PQ were increased by 10 and$20\%$ of the initial level, respectively for 3 hr and thereafter reduced by 46 and$49\%$ of the original level, respectively at 24 hr. However, the SOD activities treated with dark and dark+PQ were decreased by 37 and$30\%$ of the initial level, respectively, It is considered that PQ triggers the oxidation of ascorbic acid, the induction of lipid peroxidation and the inactivation of SOD under light so that PQ has inhibitory effect on the pathway of plant metabolism. -
Leaf discs were excised from spinach leaves (Spinacia oleracea L.) and floated in phosphate buffer (pH 6.8) containing paraquat solutions (0, 0.1, 1.0, 10, 20, 50 and 100 ppm), and incubated in the growth chamber under 5,500 lux illumination at
$25^{\circ}C$ for 24 hr. Treatment with paraquat caused the formation of malondialdehyde (MDA), an indicator of lipid peroxidation in leaf discs. When 1.0, 10, 20, 50 and 100 ppm of paraquat solutions were applied to leaf discs, the contents of MDA were increased by 63, 86, 100, 140 and$150\%$ of the level without paraquat treatment respectively. 1.0, 10, 20, 50 and 100 ppm of paraquat treatments reduced the amounts of ascorbic acid in leaf discs by 23, 35, 38, 42 and$56\%$ of the level without paraquat treatment, respectively. Activities of superoxide dismutase (SOD) in leaf discs of 1.0, 10, 20, 50 and 100 ppm of paraquat treatments were decreased by 23, 42, 48, 61 and$70\%$ of the level of SOD in non-treated group, respectively. The results suggest that paraquat may cause peroxidation of membrane lipid in spinach leaves as a result of paraquat-induced destruction of physiological defense against oxygen phytotoxicity. -
The naturally occurring plasmids of Vibrio species have been isolated in part to investigate their genetic traits. Among six different Vibrio species tested, Vibrio anguillarum, Vibrio fluvialis, Vibrio vulnficus, Vibrio mimicus and Vibrio furnissi did not show any presence of plasmid. One environmental isolate of Vibrio parahaemolyticus harboring plasmid was observed. The isolated plasmid was 8.7 kb by analysis with restriction endonuclease digestion. No common feature was shown relationships between the presence of plasmid and resistance against commonly used antibiotic compounds from the tested Vibrios.
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The bacteriophages lytic for Vibrio furnissi, Vibrio fluvialis and Vibrio parahaemolyticus were isolated from fish gills and shellfish. Nucleic acid of bacteriophages was prepared and restriction endonuclease profile was compared. All isolates contained deoxyribonucleic acid. V. furnissi bacteriophage from fish gills showed 2 bands with Bgl II, 1 with Pst, 3 with Hind III, I with Bam HI and 2 with EcoR 1. V fluvialis phage represented 7 fragments with Bgl II, 1 with Pst, 4 with Hind III, and 2 with EcoR 1. V. parahamolyticus produced 13 sites with Hind III and 4 sites with EcoR 1. The fragment types were varied depending on the phage isolation. All three phages were digested with Hind III and EcoR I with different sizes. V. furnissi phage were digested with 5 different restriction enzymes.
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The formation mechanism of the vortex streets in the lee of the mountain is investigated by a three-dimensional numerical model. The model is based upon the hydrostatic Boussinesq equations in which the vertical turbulent momentum flux is estimated by a turbulence parameterization scheme, but the horizontal viscosity is assumed to be constant. The results show that Karman vortex streets can form even without surface friction in a constant ambient flow with uniform stratification. The vortex formation is related to breaking of the mountain wave, which depends on the Froude number (Fr). In the case of a three-dimensional bell-shaped mountain, the wave breaking occurs when Fr is less than about 0.8, while a Karman vortex forms when Fr is less than about 0.22. Vortex formation also depends on Reynolds number, which is estimated from the horizontal diffusivity. The vortex formation can be explained by the wave saturation theory given by Lindzen (1981) with some modification. Simulations in this study show that in the case of Karman vortex formation the momentum flux in the lower level is much larger than the saturated momentum flux whereas it is almost equal to the saturated momentum at the upper levels as expected from the saturation theory. As a result, large flux divergence is produced in the lower layer, the mean flow is decelerated behind the mountain, and the horizontal wind shear forms between unmodified ambient wind. The momentum exchange between the mean flow and the mountain wave is produced by the turbulence within a breaking wave. From the result, well developed vortices like Karman vortex can be formed. The results of the momentum budget calculated by the hydrostatic model are almost the same as nonhydrostatic results as long as horizontal scale of the mountain is 10 km. A well developed Karman vortex similar to the hydrostatic one was simulated in the nonhydrostatic case. Therefore, we conclude that the hydrostatic assumption is adequate to investigate the origin of the Karman vortex from the viewpoint of wave breaking.
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Cloud streets were successfully simulated by numerical model (RAMS) including an isolated mountain near the coast, large sensible heat flux from the sea surface, uniform stratification and wind velocity with low Froude number (0.25) in the inflow boundary. The well developed cloud streets between a pair of convective rolls are simulated at a level of 1 km over the sea. The following five results were obtained: 1) For the formation of the pair of convective rolls, both strong static instability and a topographically induced mechanical disturbance are strongly required at the same time. 2) Strong sensible heat flux from the sea surface is the main energy source of the pair of convective rolls, and the buoyancy caused by condensation in the cloud is negligibly small. 3) The pair of convective rolls is a complex of two sub-rolls. One is the outer roll, which has a large radius, but weak circulation, and the other is the inner roll, which has a small radius, but strong circulation. The outer roll gathers a large amount of moisture by convergence in the lower marine boundary, and the inner roll transfers the convergent moisture to the upper boundary layer by strong upward motion between them. 4) The pair of inner rolls form the line-shaped cloud streets, and keep them narrow along the center-line of the domain. 5) Both by non-hydrostatic and by hydrostatic assumptions, cloud streets can be simulated. In our case, non-hydrostatic processes enhanced somewhat the formation of cloud streets. The horizontal size of the topography does not seem to be restricted to within the small scale where non-hydrostatic effects are important.
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Digestion of a municipal wastewater sludge by the anaerobic sequencing batch reactor(ASBR) was investigated to evaluate the performance of the ASBR process at a critical condition of high-solids-content feed. The reactors were operated at an HRT of 10 days with an equivalent loading rate of 0.8-1.5 gVS/L/d at
$35^{\circ}C.$ The main conclusions drawn from this study were as follows: 1. Digestion of a municipal wastewater sludge was possible using the ASBR in spite of high concentration of settleable solids in the sludge. The ASBRS with 3- and 4-day cycle period showed almost identical high digestion performances. 2. No adverse effect on digestion stability was observed in the ASBRS in spite of withdrawal and replenishment of$30\%\;or\;40\%$ of liquid contents. A conventional anaerobic digester could be easily converted to the ASBR without any stability problem. 3. Flotation thickening occurred in thicken step of the ASBRS throughout steady state, and floating bed volume at the end of thicken period occupied about$70\%$ of the working volume of the reactor. Efficiency of flotation thickening in the ASBRS could be comparable to that of additional gravity thickening of a completely mixed digester. 4. Solids were accumulated rapidly in the ASBR during start-up period. Solids concentrations in the ASBRS were 2.6 times higher than that in the completely mixed control reactor at steady state. Dehydrogenase activity had a strong correlation with the solids concentration. Dehydrogenase activity of the digested sludge in the ASBR was 2.9 times higher than that of the sludge in the control reactor, and about 25 times higher than that of the subnatant in the ASBR. 5. Remarkable increase in equivalent gas production of$52\%$ was observed at the ASBRS compared with the control reactor in spite of similar Quality of clarified effluent from the ASBRS and control reactor. The increase in gas production from the ASBRS was believed to be combined results of accumulation of microorganisms, higher driving force applied, and additional long-term degradation of organics continuously accumulated. -
Flocculation-spectrophotometry and streaming current detector(SCD) method were investigated and compared in order to determine the optimum dosages of synthetic cationic polymers of different charge density and molecular mass for the removal of humic acid. The optimum dosage for each of the polymers was determined with the dosage at which the lowest absorbance of humic acid was shown for the former and was determined with the dosage required during charge neutralization of humic acid for the latter. It was in good agreement between both methods and there is a strong inverse correlation between the optimum dosage and charge density of the polymers, with highly charged polymer giving the lowest optimum dosage, pointing out the importance the charge neutralization. By flocculation-spectrophotometry, it was found that the absorbance of humic acid with the amount of each of the polymers dosed, changes sharply for polymers of high charge density, but changes rather broadly for polymers of low and middle charge density. Both methods showed that a stoichiometric correlation exists between the optimum dosage of each of the cationic polymers and the negatively charged humic acid.
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The effect of various supplies of lead singly and in combination with aluminium on growth and chlorophyll biosynthesis was investigated in 7-day-old Vigna angularis seedlings. Expose to 50 uM Pb or more drastically reduced root elongation rate. Significant depressions in root growth was observed within 1 day and no recovery of growth was seen over the duration of treatment period. Root elongation decreased depending on the Pb concentrations. Root growth inhibition was stronger than shoot growth inhibition. The initiation of lateral roots appeared to be more sensitive to Pb than the growth of main roots. Inhibition of root and shoot elongation by Pb was lessened by combined exposure of Pb and Al, suggesting that the presence of Al reverse the inhibitory effect of Pb alone. With the histochemical sodium rhodizonate method the rate of Pb uptake was dependent on the Pb concentration and exposure time of the roots to Pb salts. Pb was first deposited on the root surface and then translocated radially in the root cap cells. During a longer Pb administration (up to 72 h) Pb penetration was nonuniform, with accumulation within the cortex or endodermis. There was drastic reduction in chlorophyll content by Pb. The Pb inhibition of chlorophyll synthesis was concentration dependent.
$\delta-Aminolevulinic$ acid dehydratase (ALAD) activity exhibited distinct inhibition from control. Reduction in chlorophyll content was accompanied by proportional changes in ALAD activity. Chlorophyll content and ALAD activity were less affected by combined exposure of Pb and Al, suggesting that Al has a protective effect against the inhibiting action of Pb on photosynthetic activity. -
The biosorption performances of copper were investigated by the immobilized biomass of nonliving marine brown algae Undaria pinnatifida by each of the Ca-alginate method(Ca-ALG), Ba-alginate method(Ba-ALG), polyethylene glycol method(PEG), and carrageenan method (CARR). The copper removal performance increased but the copper uptake decreased as the biomass amount was increased. However, the copper uptake by the immobilized biomass increased with increasing initial copper concentration. Among the immobilization methods, the copper uptake decreased in the following sequence: Ca-ALG > Ba-ALG > PEG > CARR. The pattern of copper uptake by the immobilized biomass fitted the Langmuir isotherm better than the Freundlich isotherm. Desorption of deposited copper with 0.05 ~0.5M HCI, resulted in no changes of the copper uptake capacity of the immobilized biomass by the immobilization methods except for PEG, through five subsequent biosorption/desorption cycles. There was no damage to the immobilized biomass which retained its macroscopic appearance in repeated copper uptake/elution cycles.
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This study was conducted for an efficient utilization of waste fly ash obtained from the power plant. Fly ash was used for synthesizing zeolite. Na-P1 zeolite could be easily synthesized from waste fly ash and showed the potential to remove heavy metal ions. The synthetic zeolite showed good adsorption property for heavy metal much better than raw fly ash and natural zeolites. Na-P1 exhibited the high adsorption efficiency with a maximum value of 260 Pb mg/g and strong affinity for
$Pb^{2+}$ ion. The metal ion selectivity of Na-P1 was determined in a decreasing order :$Pb^{2+}>Cd^{2+}>Cu^{2+}>Zn^{2+}>Fe^{3+}$ .