• BMB Reports
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• 제37권3호
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• pp.275-281
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• 2004

Rhodanese was isolated and purified from the cytosolic fraction of liver tissue homogenate of the fruit bat, Eidolon helvum, by using ammonium sulphate precipitation and CM-Sephadex C-50 ion exchange chromatography. The specific activity was increased 130-fold with a 53% recovery. The $K_m$ values for KCN and $Na_2S_2O_3$ as substrates were $13.5{\pm}2.2\;mM$ and $19.5{\pm}0.7\;mM$, respectively. The apparent molecular weight was estimated by gel filtration on a Sephadex G-100 column to be 36,000 Da. The optimal activity was found at a high pH (pH 9.0) and the temperature optimum was $35^{\circ}C$. An Arrhenius plot of the heat stability data consisted of two linear segments with a break occurring at $35^{\circ}C$. The apparent activation energy values from these slopes were 11.5 kcal/mol and 76.6 kcal/mol. Inhibition studies on the enzyme with a number of cations showed that $Mg^{2+}$, $Mn^{2+}$, $Ca^{2+}$, and $Co^{2+}$ did not affect the activity of the enzyme, but $Hg^{2+}$ and $Ba^{2+}$ inhibited the enzyme.

• Food Science and Biotechnology
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• 제15권6호
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• pp.908-913
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• 2006

Recombinant ${\beta}$-galactosidase from Bifidobacterium longum LL04 was expressed in Escherichia coli and partially purified by ammonium sulphate precipitation and anion-exchange chromatography (Mono-Q). The optimum temperature and pH of the partially purified enzyme were $50^{\circ}C$ and pH 7.0-8.0, respectively, when o-nitrophenyl-${\beta}$-D-galactopyranoside was used as a substrate. The enzyme was stable over the pH range of 5.0-9.0, and was active at $40^{\circ}C$ for more than 60 min at pH 7.0. The enzyme was significantly activated by $Na^+$ and $K^+$. Maximal activity was observed at the concentration of 10 mM for both $Na^+$ and $K^+$. The enzyme activity was strongly inhibited by most bivalent metal ions. The Km and Vmax on ONPG at 37 and $50^{\circ}C$ were 0.72, 167.9, and 0.507 mM, 310.9 U/mL, respectively.

• 한국토양비료학회지
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• 제15권2호
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• pp.110-116
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• 1982

봉나무의 생육(生育)에 적합(適合)한 $NO_3$-N과 $NH_4$-N의 공급비율(供給比率)과 이들 비율(比率)에 따른 뽕잎중의 이온균형(均衡)의 변화(変化)를 알고져 $NO_3/NH_4$비(比)를 10:0, 7:3, 5:5, 3:7, 0:10의 5개처리로 한 수경재배시험(水耕栽培試験)을 수행(遂行)한 바 다음과 같은 결과(結果)를 얻었다. 1. 뽕나무의 생육에 가장 좋은 $NO_3/NH_4$비(比)는 7:3이었다. 2. $NH_4$-N의 공급비율(供給比率)이 증가(増加)됨에 따라 엽중(葉中)의 Ca함량(含量)은 감소(減少)하였으나, K함량(含量)은 증가(増加)하였고 Mg함량(含量)은 변동이 거의 없었다. Ca함량감소(含量減少)는 K의 증가량(増加量)을 능가(凌駕)하여 양이온의 합(合)(${\sum}C$)은 감소(減少)하였다. 3. $NH_4$-N의 공급비율(供給比率)이 증가(増加)됨에 따라 엽중(葉中)의 $H_2PO_4$, $SO_4$, Cl등의 함량(含量)은 증가되었으며, 이중에서 $H_2PO_4$의 증가폭(増加幅)이 가장 컸다. 따라서 음이온의 합(${\sum}A$)은 증가(増加)되었으며, 양(陽)이온과 음(陰)이온의 차(C-A)는 $NH_4$-N 공급율(供給率)이 0%에서 100%로 증가(増加)됨에 따라 727me/kgDM에서 116me/kgDM으로 떨어졌다.

• Parasites, Hosts and Diseases
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• 제50권1호
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• pp.37-43
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• 2012

Although schistosomicidal drugs and other control measures exist, the advent of an efficacious vaccine remains the most potentially powerful means for controlling this disease. In this study, native fatty acid binding protein (FABP) from $Fasciola$ $gigantica$ was purified from the adult worm's crude extract by saturation with ammonium sulphate followed by separation on DEAE-Sephadex A-50 anion exchange chromatography and gel filtration using Sephacryl HR-100, respectively. CD1 mice were immunized with the purified, native $F.$ $gigantica$ FABP in Freund's adjuvant and challenged subcutaneously with 120 $Schistosoma$ $mansoni$ cercariae. Immunization of CD1 mice with $F.$ $gigantica$ FABP has induced heterologous protection against $S.$ $mansoni$, evidenced by the significant reduction in mean worm burden (72.3%), liver and intestinal egg counts (81.3% and 80.8%, respectively), and hepatic granuloma counts (42%). Also, it elicited mixed $IgG_1/IgG_{2b}$ immune responses with predominant $IgG_1$ isotype, suggesting that native $F.$ $gigantica$ FABP is mediated by a mixed Th1/Th2 response. However, it failed to induce any significant differences in the oogram pattern or in the mean granuloma diameter. This indicated that native $F.$ $gigantica$ FABP could be a promising vaccine candidate against $S.$ $mansoni$ infection.

• 한국미생물·생명공학회지
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• 제6권1호
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• pp.1-8
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• 1978

섬유소분해효소 생산균인 Trichoderma sp. KI 7-2의 cellulase생성을 위한 탄소원으로는 순수한 섬유소보다 볏짚 보리짚 분말을 사용하는 것이 좋았으며 1% 첨가에서 심부배양한 액을 유안농도 20~60%로 떨어뜨린 침전에서만 cellulase의 활성이 나타났다. 이 조효소의 작용최적온도는 5$0^{\circ}C$, 최적 pH는 4.2였으며, 열에 대한 안정성은 5$0^{\circ}C$에서 2시간까지 100% 활성을 유지하였고 pH에 대한 안정성은 pH4~6에서 안정하였지만 pH 4이하 및 pH 6.0 이상에서는 불안정하였다. 이러한 성질의 효소를 생산하는 균주로서 볏짚 발효시키는 몇 가지 방법을 아울러 검토하였다.

• The Korean Journal of Physiology
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• 제14권1호
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• pp.7-13
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• 1980

In the previous experiment, authors have shown that during the latter half of estrous cycle there was an increase in plasma testosterone level in the rats stimulated with hCG. To determine the physiologic significance of elevated plasma testosterone, changes of the plasma concentrations of TeBG and testosterone following hCG stimulation were analyzed in the rats having a regular 5 day cycle. The rats were divided into three groups; the control, the rats stimulated with single hCG on the day of proestrus and stimulated with hCG throughout the entire cycle. Blood samples were obtained once a day for an estrous cycle and analyzed for the binding capacity of TeBG using ammonium sulphate precipitation method and testosterone concentration by means of radioimmunoassay. Followings were the results; 1) There was no significant variation in the binding capacity of TeBG in peripheral blood during the estrous cycle of the control rats. 2) No cyclic variation in the binding capacity of TeBG was observed in the rats stimulated with single hCG on proestrus. although the levels tended to be higher in the rats with stimulation than in the control rats. 3) Continual stimulation of hCG produced a marked increase in the binding capacity of TeBG especially on the day of metaestrus. 4) The changes in the plasma level of testosterone followed the same basic pattern seen in the TeBG binding capacity. 5) From above results, the followings were suggested. a. hCG related increase of the binding capacity of TeBG is probably secondary to a modest increase in estrogen as well. b. hCG related increase of plasma testosterone in female rats is not entirely due to excess production rather in part due to decreased metabolism induced by the rise in TeBG. c. It seems likely that most of elevated testosterone shown in the rat stimulated with hCG is bound to TeBG and only small portion is unbound form which influence cellular activity. It is rather possible that an increase in TeBG could augment estrogen activity.

• Advances in materials Research
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• 제9권3호
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• pp.219-231
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• 2020

The aim of this study is to investigate the durability of fly ash based geopolymer mortar with and without protective coatings in aggressive chemical environments. The source materials for geopolymer are Fly ash and Ground Granulated Blast furnace Slag (GGBS) and they are considered in the combination of 80% & 20% respectively. Two Molarities of NaOH solution were considered such as 8M and 10M. The ratio of binder to sand and Sodium silicate to Sodium hydroxide solution (Na₂SiO₃/NaOH) are taken as 1:2 and 2 respectively. The alkaline liquid to binder ratio is 0.4. Compressive strength tests were conducted at various ages of the mortar specimens. In order to evaluate the performance of coatings on geopolymer mortar under aggressive chemical environment, the mortar specimens were coated with two different types of coatings such as epoxy and Acrylic. They were then subjected to different chemical environments by immersing them in 10% standard solutions of each ammonium nitrate, sodium chloride and sulphuric acid. Drop in compressive strength as a result of chemical exposure was considered as a measure of chemical attack and the drop in compressive strength was measured after 30 and 60 days of chemical exposure. The compressive strength results following chemical exposure indicated that the specimens containing the acrylic coating proved to be more resistant to chemical attacks. The control specimen without coating showed a much greater degree of deterioration. Therefore, the application of acrylic coating was invariably much more effective in improving the compressive strength as well as the resistance of mortar against chemical attacks. The results also indicated that among all the aggressive attacks, the sulphate environment has the most adverse effect in terms of lowering the strength.

• Asian-Australasian Journal of Animal Sciences
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• 제17권11호
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• pp.1496-1500
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• 2004

In the mammalian ovary the follicular fluid contains proteins and peptides which play an important role in growth, development and maturation of oocytes. The gonadotropins and some other factors work synergistically and regulate ovarian functions. In the present study the effect of follicular fluid proteins (FFP) and gonadotropins on progesterone secretion by granulosa cells (GC) from buffalo ovary, was investigated during culture. The follicular fluid was collected from small (<5 mm), and medium (5-8 mm) follicles obtained from buffalo ovaries. The follicular fluid from medium follicles was fractionated with ammonium sulphate at 80% saturation. The precipitated protein fraction was further resolved in to minor (peaks I, III) and major (peak II) proteins using gel filtration (Sephadex G-200). The FFP from small follicles and major FFP (peak II) at a dose of 200 $\mu$g/well, significantly stimulated progesterone secretion by pooled GC (3${\times}10^{5}$ cells/2 ml medium/well). The minor FFP did not show any stimulatory effect. There was a significant increase in progesterone secretion by pooled GC in presence of FFP and LH (10 ng/well), however, FSH (20 ng/well) with FFP exhibited an inhibitory effect. The major FFP and gonadotropins were also studied for their effect on progesterone production by GC isolated from medium and large size follicles. The GC from medium follicles were more responsive to FSH and FFP whereas GC from large follicles exhibited enhanced progesterone secretion with LH and FFP. These results indicated that FFP have their own stimulatory effect and also act synergistically with gonadotropins. The significantly different response shown by GC, for steroid hormone secretion, is based on their stage of growth and differentiation. The purification and characterization of such steroidogenic proteins may help in elucidating their role in growth and differentiation of granulosa cells.

• Asian-Australasian Journal of Animal Sciences
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• 제10권5호
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• pp.514-518
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• 1997

This study was designed to record the ovarian response towards a combined administration of heterologous buffalo FSH (buFSH) and LH (buLH) in goats. The impact of such a treatment on ovarian structures and on the plasma profile of the ovarian sex steroids (estradiol $17-{\beta}$ and progesterone) was studied. The buFSH and buLH were isolated from the buffalo pituitaries involving a procedure of ethanolic extraction, acetone precipitation followed by metaphosphoric acid - ammonium sulphate fractionation. Both gonadotrophin samples prepared were found biologically active and potent. There was an increase in the total number of follicles in the treated group ($12.66{\pm}1.24$) vis-a-vis the control group ($8.50{\pm}2.06$). However, the percentage ($51.48{\pm}6.37$) of large follicles were found reduced ($23.74{\pm}5.93$) following the treatment. Again the number of corpora lutea were observed significantly higher ($2.33{\pm}0.47C.L.$) in the treated group than (1 C. L.) in the control group. The peak plasma estradiol- $17{\beta}$ levels achieved, were much higher ($17.16{\pm}9.52pg/ml$) in the treated group, than the peak ($7.22{\pm}1.67pg/ml$) achieved in the control group. Similar trend was observed with respect to the progesterone levels (higher in the treated group). This study thus indicated that, a combined administration of heterologous buffalo FSH and LH to goats speeded up development of larger follicles nearing the ovulation stage. This population of the follicles subsequently got reduced and lead to the formation of the increased number of the corpora lutea observed in this study.

• Journal of Microbiology
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• 제39권4호
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• pp.279-285
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• 2001

Vibrio parahaemolyticus is a halophilic bacterium associated with seafood gastroenteritis. An unusual strain of Kanagawa-positive urease producing Vibrio parahaemolyticus O1:K1 was isolated from the environment and identified . A polymerase chain reaction assay revealed that this strain harbored both the tdh and the genes. The urease from this strain was studied. Maximum urease production was induced in LB medium containing 0.2% urea, 0.5% glucose, 2% NaCl and pH 5.5 with 6h of culti-vation at 37$\^{C}$ under aeration. Purification of urease was achieved by the process of whole cell lysate, 65% ammonium sulphate precipitation, DEAE-cellulose ion exchange column chromatography, Sepharose CL-6B gel filtration and oxirane activated Sepharose 6B-urea affinity chromatography with 203 fold purification and 2.2% yield. Analysis of the purified enzyme by SDS-PAGE demonstrated the presence of the subunits with a molecular weight of 85kDa, 59kDa, 41kDa and the molecular weight for the native enzyme by nondenaturing PAGE and gel filtration chromatography was 255kDa. The purified urease was stable at pH 7.5 and the opeimal pH in HEPES buffer was 8.0 The enzyme was stable at 60$\^{C}$ for 2 h with a residual activity of 32% . The addition of 10$\mu$M if NiCl$_2$maintained stability for 30 min. The Km value of the purified enzyme was 35.6 mM in urea substrate. The TD$\_$50/(median toxic dose) of the purified urease was 2.5$\mu\textrm{g}$/ml on human leukemia cells.