• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.5
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• pp.247-254
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• 2001

Silent period(SP) is transient stops of muscle activity that are induced by mechanical or electrical stimulus and the duration of silent period is a important parameter that have been associated with symptoms of masticatory dysfunction. Muscle fatigue is induced by sustained muscular contractions. It is associated with the external manifestations as the inability to maintain a desired force output, muscular tremor, and localized pain. Muscle fatigue is a parameter that have been measured or monitored the deterioration of a performance of muscles. On the study of relationship between SP and masticatory muscle fatigue, Nagasawa suggested that SP increases up to 3 min. from the beginning of clenching when the subjects performed sustained contractions at 50% maximum clenching level. In this paper, in order to evaluate a relationship between SP and muscle fatigue, 10 SPs per 1 minute are measured at 10%, 20%, 50% maximum clenching level. We used the median frequency in order to quantify the degree of muscle fatigue. However, the results shows that the duration of silent period was not significantly affected by differing levels of muscle fatigue. Therefore, we suggest that the SP is not increased or decreased as the results of muscle fatigue, also the origin of the SP generation mechanism is discussed.

• ALGAE
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• v.22 no.4
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• pp.319-323
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• 2007

This study was conducted with using chlorophyll a fluorescence (indicated as photosynthetic activity) to examine the toxic effect of 96 h exposure of heavy metals and herbicides on the benthic diatom Nitzschia sp. which was isolated from pristine sediment in Pamquat Harbour, Nova Scotia, Canada. Samples of benthic diatom were exposed to 0, 0.01, 0.1 and 1 mg L–1 of copper, 0, 1, 10 and 100 mg L–1 of chrome (VI), 0, 2.45, 24.5 and 245 mg L–1 of paraquat dichloride, and 0, 4.37, 43.7 and 437 mg L–1 of alachlor during 96 hours. The effective quantum yield of photochemistry (ΔF/Fm’) was evaluated by subjecting light acclimated samples to saturating pulses of light using a pulse amplitude modulated (PAM) fluorometer. The impact of heavy metals on Nitzschia sp. photosynthesis was not severe in < 1 mg L–1 but in the high concentrations (> 1 mg L–1) clearly increased toxic stress during 96 h. Herbicides had a limited impact during the exposure period but clearly increased stress on the benthic diatom with increasing concentrations. Acute response of Nitzschia sp. to selected heavy metals and herbicides was characterized, and the capacity of a benthic diatom to tolerate and recover from toxic stress was assessed.

• Journal of Soil and Groundwater Environment
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• v.16 no.2
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• pp.6-11
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• 2011

In this report, we provide experimental evidence that heavy metal ions could be removed using Pachymeniopsis sp., particularly soluble arsenic in leachate from soil contaminated by arsenic. We performed pilot scale of soil washing process based on our results. The adsorption of arsenic by Pachymeniopsis sp. indicated that it could be described with the Langmuir Model and the maximum adsorption capacity increased with decreasing pH (pH 3: 102.48 mg/g, pH 5: 98.32 mg/g, pH 7: 57.70 mg/g, pH 9: 43.34 mg/g) and increasing temperature (10$^{\circ}C$ : 60.38 mg/g, 20$^{\circ}C$ : 76.39 mg/g, 30$^{\circ}C$ : 112.12 mg/g). Our results revealed that soluble arsenic in leachate was removed from 24.03 mg/L to 0.6 ${\pm}$ 0.1 mg/L by Pachymeniopsis sp. for 48hours on pilot scale of soil washing process.

• Korean Journal of Ecology and Environment
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• v.40 no.4
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• pp.537-545
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• 2007

The heavy metal removal capacity of filamentous green alga Cladophora sp. cultured together with wet-mixed solidified soil (loess) was tested. A Cladophora sp. was cultured for 5d, with added Chu No. 10 medium, in stream water contaminated by high concentration of heavy metals from a closed mine effluent. Heavy metal ion concentrations of the medium and in algal tissue were measured every day during the experiment. Dissolved metals (Al, Cd, Cu, Fe, Mn, Zn) in medium were rapidly removed (over 90% elimination) within 1-2d when alga and loess were added. Dissolved heavy metals dropped by only 10% when algae were cultured without loess. The Cladophora sp. accumulated much more heavy metals when cultured with loess than when the alga was cultured alone. Cladophora sp. exhibited a maximum uptake capacity for Al ($17,000{\mu}g^{-1}$ algal dry weight). The metal bioremoval capacities of the algae were in the order Al, Fe, Cu, Mn, Zn and Cd. The heavy metal removal capacity of Cladophora sp. showed significant increases when wet-mixed solidified soil was added to culture media.

• Fisheries and Aquatic Sciences
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• v.6 no.1
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• pp.27-33
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• 2003

A lactic acid bacterium showing antimicrobial activity against fish pathogen was isolated from gastrointestinal tract of flounder for the purpose of use as an aquaculture probiotics. From the analysis of morphological and physiological characteristics, the isolated strain was named as Lactococcus sp. HM58. Antimicrobial substance (AMS) from Lactococcus sp. HM58 showed strong growth inhibitory activity against Streptococcus sp., which is a fish pathogenic bacterium. AMS was presumed a proteinaceous compound with stability in heat and wide pH range from 2 to 10. It was started to produce in exponential growth phase and was not produced any more in stationary phase. It showed comparatively broad antimicrobial spectrum against most of gram positive bacteria used for this study. About $84\%$ of Lactococcus sp. HM58 was able to survive in the artificial gastric juice though it was low to the extent in the artificial bile juice. In the sensitivity test for various antibiotics, this strain was highly sensitive for doxycycline, erythromycin, amoxicillin clavu1anic acid and ampicillin.

• KSBB Journal
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• v.26 no.5
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• pp.407-411
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• 2011

Microbial fuel cell (MFC) wes enriched using sludge in wastewater treatment. The microbial community of activated sludge and enriched MFC were analyzed by FISH (fluorescent in situ hybridization) and 16S rDNA sequencing. Bacteroidetes group were pre-dominant in activated sludge by FISH. ${\alpha}$ group, ${\gamma}$ group and Acintobacter group were dominant and they were similar to distribution. The average value of 10 peak of MFC is 0.44C. When MFC wase enriched by sludge, ${\gamma}$-Proteobacteria, Plantomycetes group increased 70% and 60%, respectively. In results of 16S rDNA sequencing, Sphiringomonas sp. was comprised in ${\alpha}$ proteobacteria and Enterobacter sp., Klebsiella sp., Acinetobacter sp., Bacillus sp. were comprised in ${\gamma}$ proteobacteria and Chryseobacterium sp. was comprised in Flavobacteria were isolated from sludge.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.1
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• pp.36-43
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• 2015

Excess use of chemical fertilizer causes soil acidification and accumulation of salt, and thus might bring to desertification of soil. To overcome this problem, it needs limited usage of chemical fertilizer and increased usage of natural fertilizer as an alternative. In this study, dry soil-borne Bacillus sp. SHL-3, which was isolated from arid and barren soil, with plant growth promoting activity was isolated for identification and to determine optimal culture condition. A bacterial strain SHL-3 had the IAA productivity ($5.16{\pm}0.10mg\;L^{-1}$), ACC deaminase activity ($0.36{\pm}0.09$ at 51 hours) and siderophore synthesis. It was identified as genus Bacillus sp.. Also, optimal culture condition of SHL-3 were $20^{\circ}C$ and pH 7 in LB medium. Bacillus sp. SHL-3 had up to 4% salt tolerance in the medium. We evaluated the plant growth promotion ability of SHL-3 using yam (Dioscorea japonica Thunb.). As a result, Bacillus sp. SHL-3 was effective on the increase of the shoot length (202.4% increase for 91 days). These results indicate that Bacillus sp. SHL-3 can serve as a promising microbial resource for the biofertilizers of soil.

• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.413-419
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• 1998

Aryl acylamidase [EC 3.5.1.13] present in an acetaminophen-assimilating Pseudomonas sp. has been purified to a homogeneity using series of ammonium sulfate fractionation, DEAE-Sephacel anion exchange, Phenyl-Sepharose CL-4B hydrophobic, and Sephadex G-100 gel-permeation chromatography. The molecular weight, which was estimated by gel-permeation filtration and sodium dodecyl sulfate polyacylamide gel electrophoresis, was about 57 kDa and 56 kDa, respectively, indicating that this enzyme is a monomeric protein. The optimum pH was 10.5 and the optimum temperature was 40$^{\circ}C$. After incubation of the enzyme at 50$^{\circ}C$ for 30 min, residual activity of the enzyme was 34% compared to its original activity. The Km values for acetaminophen and 4'-nitroactanilide were 0.10 mM and 0.11 mM, respectively.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.223-226
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• 1999

A bacterial strain producing high level of an extracellular phytase was isolated from cooked rice and identified as a strain of Bacillus sp. and designated as Bacillus sp. KHU-10. Optimum culture conditions were investigated for the maximum productivity of phytase by Bacillus sp. KHU-10. 1.0% Maltose and 1.0% peptone with 0.5% beef extract were the best carbon source and nitrogen source, respectively. The addition of $CaCl_2$, stimulated the enzyme productivity with concentration between 0.01% and 0.2%, in the medium. Although sodium phosphate increased the cell mass, the enzyme activity decreased. Calcium phytate and wheat bran containing phytate did not enhance the enzyme production. Under the optimum medium, the production of the phytase reached the highest level of 0.2 unit/ml after 4 days of incubation.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.383-389
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• 1991

In order to produce alkaline protease, psychrotrophic bacterium which have high enzyme activity at low temperature, was isolated by using enrichment culture from various samples and identified as genus alkalopsychrotropic Pseudomonas sp. RP-222. The optimal culture conditions for enzyme production were pH- 10.0, temperature-$20^{\circ}C$ and culture time-4 days. The optimum pH and temperature for the enzyme activity were pH 10.5 and $40^{\circ}C$, respectively and the enzyme was relatively stable at pH 7.0~13.0 and below $50^{\circ}C$. The enzyme was inhibited by ethylenediaminetetraacetate and phenylmethylsulfonylfluoride, indicating that the enzyme was a serine metalloenzyme, but considerably stable in the presence of surface active agents. Activity of the enzyme was increased by the addition of 0.05% Na-$\alpha$-olefin sulfonate.