• Korean Journal of Pharmacognosy
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• v.25 no.3
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• pp.238-248
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• 1994

The hypoglycemic and metabolic effects of Commelina communis L. extract were investigated in alloxan induced diabetic rats. The increased blood glucose level in the diabetic rats was significantly reduced and the loss of body weight was recovered with the treatment of the plant protein fractions($30{\sim}70%$ ammonium sulfate precipitates). Administration of the plant protein fractions elicited the significant increase of glucose-6-phosphate dehydrogenase (G-6-P DH) activity and liver weight which were decreased in the diabetic rat liver. G-6-P DH was partially purified from extract- or insulin-treated diabetics, diabetic control, and normal rat liver and studied for the biochemical properties. The $K_m$ value(9.002 mM) of diabetic rat liver enzyme was greatly higher than that (0.033 mM) of normal enzyme indicating the affinity of enzyme for the substrate was significantly reduced in the diabetic rat liver. This reduced affinity of enzyme for the substrate in the diabetic rat was recovered in the extract- or insulin-treated rat liver enzyme having 0.164 or 0.208 mM of their $K_m$ values, respectively. Although there was no significant difference in the optimum pH(6.0) and optimum temperature($37^{\circ}C$) of enzyme among the experimental groups, the dependence of their activities on pH appeared to be slightly resistant in the extract- or insulin-treated group compared to the diabetic group. In order to investigate the antigenicity of rat liver enzyme among experimental groups, enzyme-linked immunosorbent assay was carried out by using anti-G-6-P DH anti-serum. Absorbance(0.102) shown in the normal rat liver was reduced even below zero in the alloxan-diabetic rat liver, but increased again in the extract- or insulin-treated rat liver(0.096 or 0.118, respectively). The result of this study suggested that G-6-P DH may be used as a marker enzyme to diagnose and to indicate the progress of the diabetics, and the hypoglycemic effect of the extracts of Commelina communis L. was certainly associated with action or mode of G-6-P DH on the rat liver.

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.267-273
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• 2018

Hydrothermal liquefaction of Chlorella vulgaris feedstock containing 80% (w/w) water was conducted in a batch reactor as a function of temperature (300, 325 and $350^{\circ}C$) and reaction times (5, 10 and 30 min). The biocrude yield, elemental composition and higher heating value obtained for various reaction conditions helped to predict the optimum conditions for maximizing energy recovery. To optimize the recovery of inorganic nutrients, we further investigated the effect of reaction conditions on the ammonium ($NH_4{^+}$), phosphate ($PO_4{^{3-}}$), nitrate ($NO_3{^-}$) and nitrite ($NO_2{^-}$) concentrations in the aqueous phase. A maximum energy recovery of 78% was obtained at $350^{\circ}C$ and 5 min, with a high energy density of 34.3 MJ/kg and lower contents of oxygen. For the recovery of inorganic nutrients, shorter reaction times achieved higher phosphorus recovery, with maximum recovery being 53% at $350^{\circ}C$ and 5 min. Our results indicate that the reaction condition of $350^{\circ}C$ for 5 min was optimal for maximizing energy recovery with improved quality, at the same time achieving a high phosphorus recovery.

• Journal of Climate Change Research
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• v.6 no.3
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• pp.249-256
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• 2015

This study was conducted to investigate the effects of different levels and types of nitrogen fertilizer on seedlings and soil chemical properties in a semi-arid area, Mongolia. 2-year-old Populus sibirica and 4-year-old Ulmus pumila seedlings were planted in May 2014. Six treatments with three levels of nitrogen (low-level: urea $5g\;tree^{-1}$; medium-level: urea $15g\;tree^{-1}$, ammonium sulfate $33g\;tree^{-1}$, urea $15g\;tree^{-1}$ with potassium phosphate $10g\;tree^{-1}$; high-level: urea $30g\;tree^{-1}$) were applied and for the medium-level of nitrogen, different types of fertilizer were treated. Survival rate, root collar diameter (RCD) growth rate, leaf nitrogen concentration of seedlings, and soil chemical properties were determined in August 2014. The seedling survival rate of both species decreased as the level of nitrogen increased. This result can be explained by water stress caused by nitrogen fertilization in arid regions. The RCD growth rate of P. sibirica was significantly decreased by the treatment of high-level of nitrogen due to excessive nitrogen fertilization, and was increased by the treatment of ammonium sulfate due to sulfur which might promote nitrogen uptake. The leaf nitrogen concentration of P. sibirica did not change by the treatment of low-level of nitrogen, and was increased by the treatment of medium-level of nitrogen. There were no significant differences in the RCD growth rate and the leaf nitrogen concentration of U. pumila among the six treatments. None of soil chemical properties was affected by nitrogen fertilization. Overall, the low-level of nitrogen showed no effect on seedlings and soil chemical properties, except on survival rate of U. pumila and the high-level of nitrogen was considered excessive fertilization. Continuous monitoring of medium-level nitrogen fertilization including the ammonium sulfate, which increased early growth of seedlings, would be needed to elucidate the effect of fertilization on seedling growth and soil properties in a semi-arid region.

• Journal of Aquaculture
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• v.9 no.3
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• pp.239-245
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• 1996

As one of the red tide control method, montmorillonite was used to eliminate the causative organisms in Korea and Japan. We assayed the loess to replace the montmorillonite because it distribute in large quantity and nearby the red tide occurrence in South Coast of Korea. By using the mixture of loess and coal ashes, we examined the decreasing level of nutrients such as ammonia and phosphate, the elimination of causative organisms as a chlorophyll a content, and the harmful effect on aquaculture orgarnisms in cage culture farms. Half of the ammonium and phosphate was adsorbed by the loess particles, but only $25\%$ of ammonium was adsorbed by the coal ashes particles. In water column test, the particles of loess and coal ashes were settled down by $80\%$ in 20 minutes, the red tide organisms was eliminated by $80\%$ after 2 hours in 1,000 ppm of loess suspension, but the organisms were eliminated only $30\%$ by the same concentration of coal ashes. The harmful test of fishes and invertbrates, we observed any other negative effects of test animals than a tint deceleration in yellowtail.

• Microbiology and Biotechnology Letters
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• v.16 no.2
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• pp.119-125
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• 1988

$\beta$-Glucosidase of Cellulomonas sp. CS1-1 in cellular compartment was localized with cell-bound form while Avicelase and carboxymethylcellulase (CMCase) were appeared with extracellular enzyme. Cell growth on cellulose or CMC minimal broth was increased by glucose addition. $\beta$-Glucosidase production on cellobiose or CMC minimal broth was repressed by the addition of glucose. However, on CMC minimal broth, the enzyme production was specially stimulated by cellobiose addition. $\beta$-Glucosidase production was also induced by CMC, starcth and maltose compared with glycerol, arabinose, xylose and trehalose. From the above results, it was concluded that glucose effect on $\beta$-glucosidase biosynthesis showed catabolite repression, but enzyme production was induced by cellobiose, CMC, and starch, indicating that $\beta$-glucosidase is inducible enzyme. Yeast extract stimulated $\beta$-glucosidase production more than peptone and ammonium sulfate. $\beta$-Glucosidase activity was increased with 50mM MgCl$_2$in 10mM potassium phosphate buffer (pH 7.0). Optimum conditions for enzyme activities were pH 6.0 and 42$^{\circ}C$, Km value of $\beta$-glucosidase for p-nitrophenyl-$\beta$-D-glucosidase was 0.256mM and Ki for $\beta$-D(+)-glucose was 9.0mM.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1211-1216
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• 2004

A MNNG (N-methyl-N'-nitro-N-nitrosoguanidine) induced chromium resistant strain ($Cr^{r}18$) of unicellular cyanobacterium Anacystis nidulans has been isolated and characterized. The resistant strain could grow (although restricted to $50\%$ of control) in chromium concentration (180${\mu}M$) lethal to the wild-type. Sublethal ($160{\mu}M$) concentration of $Cr^{6+}$ significantly reduced (13-$37.5$) all the photosynthetic pigments of A. nidulans with maximum reduction in phycoerythrin followed by ChI $\alpha$. Pigments of A. nidulans were drastically decreased in lethal concentration of Cr^{6+} with maximum reduction in phycoerythrin ($75\%$) and allophycocyanin ($67.5\%$). Resistant strain $Cr^{r}18$ resisted toxic effects of sublethal and lethal concentrations of $Cr^{6+}$ on photosynthetic pigments as revealed by less decrease in pigments as compared to A. nidulans. Effect of $Cr^{6+}$ stress was also studied on nitrogen assimilation and phosphate uptake. Sublethal concentration of $Cr^{6+}$ drastically reduced ($71.5\%$) nitrate uptake by A. nidulans while a decrease of $29\%$ was observed in strain $Cr^{r}18$. Short (2 day) exposure of A. nidulans and its resistant strain $Cr^{r}18\;to\;Cr^{6+}$ did not affect nitrate reductase and glutamine synthetase (transferase), whereas longer (10 day) exposure to $Cr^{6+}$ lowered activities of both enzymes in A. nidulans but not significantly in the strain $Cr^{r}18$. Ammonium uptake by both strains was not affected by $Cr^{6+}$. Thus, $Cr^{6+}$ affected photosynthetic pigments, nitrogen assimilation, and phosphate uptake of A. nidulans, while strain $Cr^{r}18$ was able to resist toxic effects of the metal. Advantages of using strain $Cr^{r}18$ for bioremediation purposes have been evaluated by studying $Cr^{6+}$ removal from the solution. Resistant strain $Cr^{r}18$ was able to remove $33\%$ more $Cr^{6+}$ than A. nidulans and thus it can prove to be a good candidate for bioremediation of $Cr^{6+}$ from polluted waters.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.68-72
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• 2005

Leuconostoc citreum is one of the representative strains of Leuconostoc spp. that show fast growth rates in fermented vegetables. Sequential experimental designs including the Plackett-Burman design, fractional factorial design, steepest ascent analysis, central composite design and response surface methodology were introduced tooptimize and improve the medium for Leuconostoc citreum. Fifteen medium ingredients were examined and glucose (20 g/l), yeast extract (12.5 g/l), sodium acetate trihydrate (6.12 g/l), potassium phosphate (42.55 g/l) and dibasic ammonium citrate (4.12 g/l)were chosen as the best components to give a critical and positive effect for cell-growth. The biomass was increased to 2.79 g/l (169%), compared to the 1.65 g/l in MRS medium.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.278-284
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• 2004

Leuconostoc citreum is one of the representative strains of Leuconostoc spp. that show fast growth rates in fermented vegetables. Sequential experimental designs including the Plackett-Burman design, fractional factorial design, steepest ascent analysis, central composite design and response surface methodology were introduced to optimize and improve the medium for L. citreum. Fifteen medium ingredients were examined and glucose ($20 g/\ell$), yeast extract ($12.5g/\ell$), sodium acetate trihydrate ($6.12g/\ell$), potassium phosphate ($42.55g/\ell$), and dibasic ammonium citrate ($4.12g/\ell$), were chosen as the best components to give a critical and positive effect for cell-growth. The biomass was increased to ($2.79g/\ell$), (169%), compared to the $1.65g/\ell$ in MRS medium.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.5
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• pp.457-464
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• 2001

Algal growth potential (AGP) assay using Cochlodinium polykrikoides was conducted in Saryang Island coast where C. polykrikoides red tide occurred annually from July to October 1998. The effects of macro- and micro-nutrients on the growth of C. polykrikoides were specifically evaluated by the algal assay method. Two different types of growth response of C. polykikoides for the addition of nutrients were clearly obseued. For both before and after C. polykrikoides occurrence, the growth of C. polykikoides was significantly stimulated by the addition of either nitrate or ammonium of $50{\mu]M$ with phosphate of $5{\mu}M$. The addition of a single nutrient had no clear effect on the growth of C. polyhikoides and the addition of trace metals, vitamins, and EDTA etc. did not stimulate the algal growth, also. This result indicates that both N and P potentially limited the growth of C. polyhikoides in this period. However, during a bloom of C. polyhikoides, the growth was unlikely to be stimulated by the addition of both macro- and micro-nutrients. At that time the nutrient concentration of Saryang Island coast was $24.33{\mu}M$ for ammonium, $1.61{\mu}M$ for phosphate, and $0.58{\mu}M$ for nitrate, respectively. The concentrations of nutrients increased, on average, 8.2-fold for ammonium and 4.8-fold for phosphate, decreased 3.3-fold for nitrate compared to both before and after the red tide. This result shows that the growth of C. polykikoides was not limited by the nutrients during the bloom in September. Therefore, our results suggest that the C. polykrikoides red tide may outbreak especially when the water is fertilized due to the increased N and P.

• Journal of Life Science
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• v.22 no.5
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• pp.575-581
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• 2012

This study was conducted to develop an economical optimum medium composition for the mass production of $Lactobacillus$ $plantarum$ and $Lactobacillus$ $reuteri$, livestock probiotics. Medium ingredient factors were selected on the basis of MRS broth composition, and the 15 ingredient variables were as follows: sucrose, glucose, molasses, yeast extract, corn steep liquor, soy peptone, dipotassium phosphate, manganese chloride, magnesium chloride, tween 80, sodium chloride, sodium acetate, ammonium citrate, sodium sulphate, and ferrous sulphate. The Plackett Burman design, consisting of 20 runs, was employed for the analysis of ingredient effects on cell growth of $L.$ $plantarum$ and $L.$ $reuteri$. As a result, sucrose, glucose, molasses, yeast extract, corn steep liquor, soy peptone, sodium acetate, and ammonium citrate positively influenced the growth of $L.$ $plantarum$. Additionally, yeast extract, soy peptone, $K_2PHO_4$, and tween 80 positively influenced the growth of $L.$ $reuteri$. Positive effects were found from sucrose, yeast extract, and soy peptone in the integrated analysis of the effects of both $L.$ $plantarum$ and $L.$ $reuteri$. Finally, effective medium components for both strains were found as follows: sucrose (20.0 g/l), glucose (5.0 g/l), soy peptone (11.0 g/l), yeast extract (5.0 g/l), $K_2PHO_4$ (0.2 g/l), $CH_3COONa$ (2 g/l), and $MgCl_2$ (0.02 g/l).