• Asian-Australasian Journal of Animal Sciences
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• v.3 no.2
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• pp.115-120
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• 1990

Extracellular nuclease(s) in buffalo rumen fluid were purified from strained rumen fluid by a procedure involving Seitz filtration, acetone fractionation and gel filtration on Sephadex G-100. The enzyme resolved into two peaks exhibiting both DNase and RNase activities. The molecular weight of enzyme corresponding to peaks I and II were approximately 30,000 and 12,000 respectively. The properties of enzymes from the two peaks, however, were same. Optimum temperature for both DNase and RNase activities was at $50^{\circ}C$. Whereas DNase activity was stable upto $60^{\circ}C$, RNase activity was stable only up to $50^{\circ}C$. DNase activity recorded two pH optima, one at pH 5.5 and the other at pH 7.0. RNase activity recorded a broad pH optimum between pH 6.0-8.0. pH stability of the enzyme coincided with pH optima for both the activities. DNase activity was stimulated by $Mg^{2+}$ and $Mn^{2+}$ and inhibited by $Fe^{2+}$, $Zn^{2+}$, $Hg^{2+}$ and $Ag^+$. RNase activity was also stimulated by $Mg^{2+}$ and $Mn^{2+}$ and inhibited by $Cu^{2+}$, $Fe^{2+}$, $Zn^{2+}$, $Hg^{2+}$ and $Ag^+$. Reducing agents stimulated both the activities.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.4
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• pp.648-657
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• 1997

In order to investigate the polymorphism of wagnerite, the single phase of$Mg_3(PO_4)_2$ was synthesized by heating the stoichiometric mixture of $Mg_3(PO_4)_2$ and $MgF_2$ in a sealed platinum tube at $1040^{\circ}C$ (or 3 hours, One reversible inversion was detected at $1255^{\circ}C$ and the thermal decomposition was not observed until it reached the melting point. As a result, wagnerite is thermally stable enough to be used as pigments for glazes and plastics if substituted with divalent metal ions. The contractions of d-values in $Zn_4P_2O_8F_2$ and $Zn_3MgP_2O_8F_2$ phases were observed by the substitution with metal ions which resulted in intense purple, gold and green colors. Among the several attempts of charge - coupled sub-stitution, only $A^{1+}A_3^{2+}X^{5+}X^{6+}O_8_F2$ compositions were successful to synthesize the wagnerite phase.

• The Korean Journal of Mycology
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• v.14 no.2
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• pp.101-107
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• 1986

The properties of carboxyl proteinase which was contained in Poria cocos (Schw.) Wolf were investigated by means of the purification with 0.65 ammonium sulfate saturation, DEAE cellulose and Sephadex G-75 gel filtration. This enzyme was found to hydrolyze only peptide bond between glutamyl-L-tyrosine of carbobenzoxy-L-glutamyl-L-tyrosine among the synthetic substrates of carbobenzoxy-L-glutamyl-L-tyrosine, hippuryl- L-phenylalanine and hippuryl-L-arginine. This enzyme was inhibited by $Zn^{+2},\;Fe^{+2},\;Ca^{+2},\;CN^{-1},\;P_2O_7^{-4}$ ions, but stimulated by $Hg^{+2}$ ion. Also, this enzyme was inhibited by organic compounds such as L-lysine, L-phenylalanine, hippuryl-L-phenylalanine, diazoacetyl-DL-norleucine methyl ester (DAN) and 1,2-epoxy-3-(P-nitrophenoxy)propane(EPNP). In particular, the activity was inhibited by L-lysine till 20 minutes of preincubation time rapidly, and by DAN in the presence of $Cu^{+2}$ ion more rapidly after 30 minutes than DAN in the absence of $Cu^{+2}$ ion. L-Lysine was found to be a competitive inhibitor and its $K_i$ value was determined to be 0.12 mmole by Dixon plot.

• Journal of the Korean Chemical Society
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• v.44 no.5
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• pp.403-409
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• 2000

The formation and dissociation rates of $Zn^{2+}$ Complexes with l,4,7,10-tetraaza-13,16-diox-acyclooctadecane-N,N',N",N'"-tetraacetic acid (1), 1,4,7,10-tetraaza-13,16- dioxacyclooctadecane-N,N',N",N'"-tetramethylacetic acid (2), and 1,4,7,10-tetraaza-13,16- dioxacyclooctadecane-N,N',N",N'"-tetrapropionic acid(3) have been measured by stopped-flow and conventional spectrophotometry. Observations were made at 25.0$\pm$0.1 $^{\circ}C$ and at an ionic strength of 0.10 M NaClO$_4$. The formation reactions of $Zn^{2+}$ ion with 1 and 2 took place by the rapid formation of an intermediate complex (ZnH$_3L^+$) in which the $Zn^{2+}$ ion is incompletely coor-dinated. This might then lead to be a final product in the rate-determining step.ln the pH range 4.76-5.76, the diprotonated (H2L2-) form is the kinetically active species despite of its low concentration. The stability con-stants (log$K_{(ZnH$_3$3$L^+$)}$) and specific water-assisted rate constants (koH) of intermediate complexes have been deter-mined from the kinetic data. The dissociation reactions of $Zn^{2+}$ complexes of 1,2, and 3 were investigated with $Cu^{2+}$ ions as a scavenger in acetate buffer. All complexes exhibit acid-independent and acid-catalyzed con-tributions. The effect of buffer and $Cu^{2+}$ concentration on the dissociation rate has also been investigated. The ligand effect on t dissociation rate of $Zn^{2+}$ complexes is discussed in terms of the side-pendant armsand the chelate ring sizes of the ligands.

• Journal of Life Science
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• v.21 no.3
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• pp.435-443
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• 2011

The purpose of this study is to identify the effects of exercise training [ET, 10~18 m/min (speed), 20~30 min (exercise duration)/a day for 5 day/wk, 6 wk) on PGC-$1{\alpha}$, GLUT-1, Tfam, Cu,Zn-SOD and Mn-SOD proteins in brain of STZ-induced diabetic rats. The male Sprague-Dawley (SD) rats were single-injected intraperitoneally with 50mg/kg of streptozotocin (STZ) to produce STZ-induced diabetic rats. Rats were divided into 3 experimental groups with 8 rats in each group, as follows: (1) non-STZ group (n=8), (2) STZ-CON group (n=8), (3) STZ-EXE group (n=8). The results of this study suggest that i) serum glucose level was significantly reduced in STZ-EXE group compared with STZ-CON group (p<0.05), ii) PGC-$1{\alpha}$ (p<0.001), mtPGC-$1{\alpha}$ (p<0.001), GLUT-1 (p<0.001), and mtTfam (p<0.001) proteins in brain of STZ-induced diabetic rats were significantly increased in STZ-EXE group compared with STZ-CON group, iii) Cu,Zn-SOD (p<0.001) and Mn-SOD (p<0.01) proteins in the STZ-induced diabetic rats were significantly increased in STZ-EXE group compared with STZ-CON group. In conclusion, the findings of the present study reveal that treadmill exercise training increases brain GLUT-1 protein level possibly through up-regulation of PGC-$1{\alpha}$ and Tfam proteins which represent key regulatory components of stimulation of brain mitochondrial biogenesis. In addition, treadmill exercise training may prevent oxidative stress by up-regulation of Cu,Zn-SOD and Mn-SOD proteins in the STZ-induced diabetic rats.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2691-2696
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• 2009

Effects of representative group II and transition metal ions on the stability of the $poly(dA){\cdot}[poly(dT)]_2$ triplex were investigated by the van’t Hoff plot constructed from a thermal melting curve. The transition, $poly(dA){\cdot}[poly(dT)]_2\;{\rightarrow}\;poly(dA){\cdot}poly(dT)\;+\;poly(dT)$, was non-spontaneous with a positive Gibb’s free energy, endothermic (${\Delta}H^{\circ}$ > 0), and had a favorable entropy change (${\Delta}S^{\circ}$ > 0), as seen from the negative slope and positive y-intercept in the van’t Hoff plot. Therefore, the transition is driven by entropy change. The $Mg^{2+}$ ion was the most effective at stabilization of the triplex, with the effect decreasing in the order of $Mg^{2+}\;>\;Ca^{2+}\;>\;Sr^{2+}\;>\;Ba^{2+}$. A similar stabilization effect was found for the duplex to single strand transition: $poly(dA){\cdot}poly(dT)\;+\;poly(dT)\;→\;poly(dA)\;+\;2poly(dT)$, with a larger positive free energy. The transition metal ions, namely $Ni_{2+},\;Cu_{2+},\;and\;Zn_{2+}$, did not exhibit any effect on triplex stabilization, while showing little effect on duplex stabilization. The different effects on triplex stabilization between group II metal ions and the transition metal ions may be attributed to their difference in binding to DNA; transition metals are known to coordinate with DNA components, including phosphate groups, while group II metal ions conceivably bind DNA via electrostatic interactions. The $Cd_{2+}$ ion was an exception, effectively stabilizing the triplex and melting temperature of the third strand dissociation was higher than that observed in the presence of $Mg_{2+}$, even though it is in the same group with $Zn_{2+}$. The detailed behavior of the $Cd_{2+}$ ion is currently under investigation.

• Journal of Life Science
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• v.13 no.5
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• pp.618-625
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• 2003

Investigations were carried out to optimize the culture conditions for the production of xylanase by Paenibacillus sp. DG-22, a moderately thermophilic bacterium isolated from timber yard soil. Xylanase production showed a cell growth associated profile. Xylanase activity was found only in the culture supernatant, while $\beta-xylosidase$ activity was mainly associated with the cells. The formation of xylanase activity was induced by xylan and repressed by glucose and xylose. The production profile of xylanase was examined with various commercial xylan and maximum yield was achieved with 0.1∼ 0.5% birchwood xylan. Among various nitrogen sources tested, yeast extract was optimal for the production of xylanase. The xylanase activity was inhibited by $Co^{2+},\; Cu^{2+},\; Fe^{3+},\; Hg^{2+}\;$ and$\;Mn^{2+}$ ions while $Ca^{2+},\; Mg^{2+},\; Ni^{2+},\; Zn^{2+}$ions and DTT stimulated xylanase activity Mercury (II) ion at 5 mM concentration abolished all the xylanase activity. The predominant products of xylan-hydrolysate were xylobiose, xylotriose, and higher xylooligo-saccharides, indicating that the enzyme was an endoxylanase.

• Economic and Environmental Geology
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• v.27 no.5
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• pp.469-477
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• 1994

Many researchers have investigated most representative sequential extraction method using various reagents for determining the chemical forms of metals in soils and sediments. In this paper, a newly modified method for sequential extraction scheme based on Tessier's method by Environmental Geochemistry Research, Centre for Environmental Technology, Imperial College, was introduced and examined. In comparison with Tessier's method, originally designed for sediment analysis by Atomic Absorption Spectrophotometry (AAS), the sequential extraction scheme has been developed for the multi-element analysis by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The partitioning of particulate trace elements was classified into five fractions: (i) exchangeable, (ii) bound to carbonates or specially adsorbed, (iii) bound to Fe and Mn oxides, (iv) bound to organic matter and sulphides and (v) residuals. The experimental results of the pilot study for in-house reference material (HRM2) and certified international standard reference material (SRM2711) using the modified method showed not only reasonable precision and accuracy but also acceptable overall recovery rates. In addition, mine dump soils sampled in the Dalsung Cu-W mine, Korea were prepared and sequentially extracted using the method. Most of Cu was bound to organic matter/sulphides and residual fractions. The dominant fraction of soil Pb and Zn in the study area was found in the residuals. The fraction of Cd showed a wide variation between samples and could be found bound to the carbonates or specially adsorbed, oxides, organic fraction and residuals. The recovery rates of Cd, however, were poor due to relatively low Cd concentrations in soils. The heavy metals in these mine dumps appear to be in the more inert forms and should not be readily bioavailable. The soils, however, had very low pH values (average 4.1) and had sandy textures; consequently, rapid infiltration of rainfall may increase leaching of Zn and Cd which were found to be around 5 to 10% of the exchangeable fraction. As a result of the investigation of this study, it has been strongly recommended that these mine waste materials should still be considered a significant contaminant source and will need environmental remediation to prevent pollutants from being released into the environment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.2
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• pp.126-140
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• 2011

Genetic determinants of two metallothionein isoforms (MT-A and MT-B) were isolated and characterized from the perciform species, rockbream (Oplegnathus fasciatus). Rockbream MT-A and MT-B shared a high degree of homology at amino acid levels with representative orthologs from other perciform species, especially with respect to the conserved cysteine residues. At the genomic level, both MT-A and MT-B genes represent a tripartite structure typical of vertebrate MT genes. However, rockbream MT-B showed unusually large introns (1.2 kb and 0.8 kb for intron I and II, respectively), a phenomenon that has rarely been seen in other vertebrate MT genes. MT-A and MT-B transcripts were ubiquitously detected in a wide array of tissues, wherein brain and eye showed the highest basal expression levels, and the fin exhibited the lowest expression of both isoforms. The basal expression of MT-A in most tissues was significantly higher (ranging from 4- to 10-fold) than that of MT-B. Upon heavy metal exposures to Cd, Cu or Zn at 25 ppb for 48 h, MT-A and MT-B transcripts in the liver were significantly activated by Cd and moderately by Zn. On the other hand, exposure to Cu did not result in alterations of MT-A, nor in the significant suppression of MT-B. Following bacterial challenges with Escherichia coli, Edwardsiella tarda or Streptococcus iniae, MT isoforms in the liver, kidney and spleen were highly modulated and exhibited a pattern that was dependent on the bacterial species, tissues and isoforms. These results suggest that the two MT isoforms could be taken into account as potential indicators of metal toxicity and immune perturbations of this aquaculture-relevant species.

• Journal of Sericultural and Entomological Science
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• v.27 no.2
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• pp.1-6
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• 1985

To study the non-sprouting causes of mulberry saplings, 8 treatments, borax + lime + compost, borax, lime, Jamsi fertilizer No. 1, heavy nitrogen application, branch harvest, heavy harvest and no treatment were applied on the nursery garden. The tract used as the paddy field before sapling produced was very poor in the soil chemical and physical properties. The results were as follows; 1. The survial rates of saplings were higher than 98% in the treatments of borax, lime, Jamsi fertilizer No. 1, whereas were higher than 98% in the treatments of borax, lime, Jamsi fertilizer No. 1, whereas heavy nitrogen 59% and heavy harvest 71%. 2. The survial rate was showed deeper relationship with the chemical concentration in stem cortex than in root cortex, especially the content of B, Cu and Zn. 3. The nitrogen content in stem cortex was much higher in the heavy nitrogen treatment by 0.89%, where as 0.6∼0.7% in the other treatments. However, treatments of the heavy harvest and the branch harvest were around 5%. 4. In order to decrease the non-sprouting sapling rate, nursery garden should be good in soil chemical and physical properties. Harvest from saplings and heavy nitrogen application should be prevented and lime or Jamsi fertilizer should be applied to saplings.