• Title, Summary, Keyword: residual activity

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Optimal Conditions for the Distribution of Cryoprotectant into the Intact Fish Muscle of Oncorhynchus mykiss during Freeze/Thaw Cycling

  • Kong Chang Suk;Park Kun Young
    • Fisheries and aquatic sciences
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    • v.8 no.1
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    • pp.10-16
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    • 2005
  • Conditions for sufficient and rapid distribution of a cryoprotectant (sorbitol solution) into intact fish muscle (Oncorhynchus mykiss) were studied as changing in the residual Ca2+ ATPase activity during freeze/thaw cycling. Chunks of the fish muscle were immersed in 4 concentrations of sorbitol solutions ($20\%$, $30\%$, $45\%$, and $60\%$) by a shaker mechanism at 5$^${circ}C. Whole immersion samples (W) showed a higher value of the residual Ca2+ ATPase activity than those in the untreated controls (C), except in the treated controls (TC), while less effect of immersion concentration could be found. Comparing the extent of penetration of sorbitol into the surface layer to inner layer of immersed fish chunks, outer portion samples achieved excellent cryoprotection with $100\%$ of the residual ATPase activity values or more. For the inner portion samples, $30\%$ and $45\%$ sorbitol solution treatments indicated a higher ATPase activity than $60\%$ treatment. At high concentrations, mass transfer rates during osmotic dehydration might berapid and it causes faster surface drying by dewatering at surface solute layer. Periodically immersed and relaxed samples, W (5-3-1), led to good cryoprotection effect: W (5-3-1) indicated high residual Ca2+ ATPase activity values and the residual ATPase activity values excess $100\%$ in immersion of $30\%$ and $45\%$ sorbitol solutions.

Bioactivity of two medicinal plant Xylocarpus granatum Koen. (Meliaceae) and Sarcolobus globosus Wall. (Asclepiadaceae) of Sundarbans mangrove forest

  • Alamgir, M;Rob, Ma;Kundu, DC;Joy, JHK;Sarder, MM
    • Oriental Pharmacy and Experimental Medicine
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    • v.7 no.4
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    • pp.379-384
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    • 2007
  • Two medicinal plant of Sundarbans mangrove forest has been tested for the evaluation of growth inhibitory and antibacterial activity. The methanol extract of Xylocarpus granatum stem bark showed potent wheat rootlet ($IC_{50}=0.01{\mu}g/ml$) and shoot ($IC_{50}=0.23{\mu}g/ml$) growth inhibitory activity in a concentration related manner. The growth inhibitory activity was markedly decreased in residual methanol extract. The methanol extract showed antibacterial activity (MIC > 3 mg/ml) against Bacillus subtilis, Staphylococcus aureous and Proteus vulgaris. The residual methanol extract did not show any antibacterial activity. The results suggest the bioactive principle(s) of Xylocarpus granatum may be relatively non polar compound(s). The methanol extract and residual methanol extract of Sarcolobus globosus stem showed poor wheat rootlet and shoot growth inhibitory activity and no antibacterial activity.

Regulation of Enzymes Involved in Methionine Biosynthesis in Corynebacterium glutamicum

  • Yeom, Hye-Jin;Hwang, Byung-Joon;Lee, Myong-Sok;Kim, Youn-Hee;Lee, Heung-Shick
    • Journal of Microbiology and Biotechnology
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    • v.14 no.2
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    • pp.373-378
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    • 2004
  • The regulatory mechanism of methionine biosynthesis in Corynebacterium glutamicum was analyzed at the protein arid gene expression level. O-Acetylhomoserine sulfhydraylase (encoded by metY) was inhibited by 10 mM methionine to a residual activity of 10% level, whereas no such inhibition was found with cystathionine $\gamma$-synthase (encoded by metB) and cystathionine $\beta$-lyase (encoded by metC). The enzymatic activity of homoserine acetyltransferase (encoded by metX) was repressed to a residual activity of 25% level by 10 mM methionine which was added to the growth medium. Cystathionine $\gamma$-synthase and cystathionine $\beta$-lyase were also repressed by 10 mM methionine, but only to a residual activity of 50-70% level. O-Acetylhomoserine sulfhydrylase was very sensitive to repression by 10 mM methionine, showing residual activity of 13%. In addition, homoserine acetyltransferase was also repressed by 10 mM cysteine to 50% of its original activity. No repression of the enzymes by S-adenosyl methionine was observed. The pattern of repression by methionine indicated that the metB and aecD genes might be regulated by a common mechanism, while the metA and metY genes are differently regulated.

Phytase Production by Rhizopus microsporus var. microsporus Biofilm: Characterization of Enzymatic Activity After Spray Drying in Presence of Carbohydrates and Nonconventional Adjuvants

  • Sato, Vanessa Sayuri;Jorge, Joao Atilio;Oliveira, Wanderley Pereira;Souza, Claudia Regina Fernandes;Guimaraes, Luis Henrique Souza
    • Journal of Microbiology and Biotechnology
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    • v.24 no.2
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    • pp.177-187
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    • 2014
  • Microbial phytases are enzymes with biotechnological interest for the feed industry. In this article, the effect of spray-drying conditions on the stability and activity of extracellular phytase produced by R. microsporus var. microsporus biofilm is described. The phytase was spray-dried in the presence of starch, corn meal (> $150{\mu}m$), soy bean meal (SB), corn meal (< $150{\mu}m$) (CM), and maltodextrin as drying adjuvants. The residual enzyme activity after drying ranged from 10.7% to 60.4%, with SB and CM standing out as stabilizing agents. Water concentration and residual enzyme activity were determined in obtained powders as a function of the drying condition. When exposed to different pH values, the SB and CM products were stable, with residual activity above 50% in the pH range from 4.5 to 8.5 for 60 min. The use of CM as drying adjuvant promoted the best retention of enzymatic activity compared with SB. Spray drying of the R. microsporus var. microsporus phytase using different drying adjuvants showed interesting results, being quite feasible with regards their biotechnological applications, especially for poultry diets.

Cation Self-Diffusin and Impurity Diffusion of Mn and Zn in CoO: (I) A comparison of the Residual Activity and the Tracer Sectioning Method

  • Lee, Jong-Ho;Martin, Manfred
    • The Korean Journal of Ceramics
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    • v.4 no.2
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    • pp.90-94
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    • 1998
  • Self diffusion coefficients of $^{67}$Co and impurity diffusion coefficients of $^{51}$Mn and $^{65}$Zn in single crystalline CoO have been measured by applying different radioactive isotopes simultaneously. To compare the residual activity method and the tracer sectioning method we analyzed our tracer diffusion experiments by using both methods simultaneously. According to our experimental results, the diffusion coefficients obtained from both methods are identical within experimental error, demonstrating the relibility of our experimental procedures. The diffusion coefficients of all the isotopes obtained during these test experiments for the methodology are similar in magnitude and show similar dependences on oxygen partial pressure. These first observations indicate that impurity diffusion of Mn and Zn occur via a vacancy mechanism as known for self diffusion of cobalt.

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Method to Reduce the Activity Loss and Pain when Injecting 18F-Florbetaben (18F-Florbetaben 주사 시 Activity 손실과 통증 감소를 위한 방법)

  • Kwon, Hyeong Jin;Choi, Jin Wook;Lee, Hyeong Jin;Woo, Jae Ryong;Kim, Yoo Kyeong
    • The Korean Journal of Nuclear Medicine Technology
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    • v.20 no.2
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    • pp.42-45
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    • 2016
  • Purpose Neuracep is used to other diagnostic evaluations of the brain to estimate beta-amyloid neuritic plaque density in adult patients with cognitive impairment and inspected cognitive impairment. $^{18}F-Florbetaben$ specially has moderate lipophilicity and property of the added ethanol. It is the subject of interest of the patient pain and residual activity after injecting. Our study is effective injection method of the radiopharmaceutical and patient care. So it is for the highest quality image. Materials and Methods Patients were targeted 70 subjects, it was injected mean $259{\pm}74MBq$ to the patients ($^{18}F-FDG$: 20 subjects, $^{18}F-FP-CIT$: 20 subjects, $^{18}F-Florbetaben$: 30 subjects). After injection (reflusing 2 times, reflusing 3 times) using a 3-way set, it measured the residual activity. When injecting $^{18}F-Florbetaben$, we evaluated the effective injection methods(3-way set method and heparin cap method). The average residual activity after the injection was compared using a statistical analysis of SPSS 12.0(ANOVA, t-test analysis). Also, elemental analysis was performed on $^{18}F-Florbetaben$ by GC (Gas Chromatography). Results When reflusing 2 times measured residual activity as follows ($^{18}F-FDG$: 1.48 MBq, $^{18}F-FP-CIT$: 7.4 MBq, $^{18}F-Florbetaben$: 32.6 MBq). And when reflusing 3 times measured residual activity as follows ($^{18}F-FDG$: 1.85 MBq, $^{18}F-FP-CIT$: 3.7 MBq, $^{18}F-Florbetaben$: 36.3 MBq). There was a significant difference when reflusing 2 times(P < 0.05) and reflusing 3 times (P < 0.05). But when reflusing 3 times, there was no significant difference relation FDG and FP-CIT (P > 0.05). $^{18}F-Florbetaben$ Residual activity according to the injection method was a significant difference (P < 0.05). GC analysis results were measured ethanol: 207665 ppm and acceton: 377.4 ppm. Conclusion $^{18}F-Florbetaben$ was high residual activity compared to FDG and FP-CIT. Heparin cap method was effective when $^{18}F-Florbetaben$ was injected. $^{18}F-Florbetaben's$ ethanol component analysis was highly measured. So it is recommended that inject to 6 sec/ml or more in order to reduce the pain.

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Bioactivity of the methanol extract of Excoecaria agallocha Linn.(Euphorbiaceae)

  • Rajia, S.;Alamgir, M.;Shahriar, M.;Choudhuri, M.S.K.
    • Oriental Pharmacy and Experimental Medicine
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    • v.6 no.2
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    • pp.102-107
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    • 2006
  • The methanol extract and residual methanol fraction of Excoecaria agallocha L. (Euphorbiaceae) stem bark was investigated in this study by wheat rootlet and shoot growth inhibition, and antimicrobial bioassay. The methanol extract and residual methanol fraction showed high inhibitory effect on both the wheat rootlet (82-89%) and shoot growth (85-90%) compared to control. The methanol extract showed a better and dose related inhibition on both the rootlet and shoot growth compared to residual methanol fraction. The $IC_{50}$ value of methanol extract for rootlet and shoot were $2.88\;{\mu}g/ml$ and $2.32\;{\mu}g/ml$, and of residual methanol fraction for rootlet and shoot were $7.91\;{\mu}g/ml$ and $4.45\;{\mu}g/ml$. The methanol extract and residual methanol fraction did not show any antibacterial activity against the tested microorganisms of clinical isolates Escherichia coli, Staphylococcus aureous, Pseudomonas aeruginosa, Proteus vulgaris and Bacillus subtilis. The plant has the potential to be a source of novel cytotoxic compound(s).

The Enzymatic Properties of Actinidine from Kiwifruit

  • Nam, Seung-Hee;Walsh, Marie K.;Yang, Kwang-Yeol
    • Food Science and Biotechnology
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    • v.15 no.3
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    • pp.453-457
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    • 2006
  • Activity and stability of kiwifruit actinidine was determined in various conditions of pH, salt, and temperature using N-${\alpha}$-CBZ-lysine P-nitrophenyl ester as the substrate. Actinidine activity was low below pH 6, and undetectable below pH 3. The enzyme was stable in a pH range of 6.0-8.5. At $4^{\circ}C$ the enzyme was inactive in the presence of greater than 36% vinegar and in 2 M NaCl. Actinidine at $25^{\circ}C$ was unstable in 24% vinegar but stable in up to 3 M NaCl. With regard to freeze-thaw stability, actinidine retained 85% residual activity after being frozen at $-20^{\circ}C$ for 3 days. Based on Arrenius and Lineweaver-Burk plots, actinidine became unstable at greater than $45^{\circ}C$ with only 30% residual activity remaining after 6 min. The Km, kcat, and kcat/Km values of actinidine were $56\;{\mu}M$, 67/sec, and $1.2\;{\mu}M/sec$, respectively.

Novel Properties for Endoglucanase Acquired by Cell-Surface Display Technique

  • Shi, Baosheng;Ke, Xiaojing;Yu, Hongwei;Xie, Jing;Jia, Yingmin;Guo, Runfang
    • Journal of Microbiology and Biotechnology
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    • v.25 no.11
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    • pp.1856-1862
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    • 2015
  • In order to improve the stability of endoglucanase under thermal and acidic conditions, the endoglucanase gene was fused to the N-terminus of the Saccharomyces cerevisiae pir gene, encoding the cell wall protein PIR. The fusion gene was transformed into Pichia pastoris GS115 for expression. A resulting strain with high expression and high activity was identified by examining resistance to Geneticin 418, Congo red staining, and quantitative analysis of enzyme activity. SDS-PAGE analysis revealed that the endoglucanase was successfully displayed on the yeast cell surface. The displayed endoglucanase (DEG) showed maximum activity towards sodium carboxyl methyl cellulose at approximately 275 IU/g cell dry weight. DEG exhibited greater than 60% residual activity in the pH range 2.5-8.5, higher than free endoglucanase (FEG), which had 40% residual activity at the same pH range. The highest tolerated temperature for DEG was 70℃, much higher than that of FEG, which was approximately 50℃. Moreover, DEG showed 91.1% activity at 65℃ for 120 min, while FEG only kept 77.8% residual activity over the same period. The half-life of DEG was 270 min at 65℃, compared with only 150 min for FEG. DEG could be used repeatedly at least three times. These results suggest that the DEG has broad applications as a yeast whole-cell biocatalyst, due to its novel properties of high catalytic efficiency, acid-thermal stabilities, and reusability.

Production and Characterization of Nitrate Reductase Deficient Mutants in Petunia parviflora

  • Lee, Cheol-Hee
    • Korean Journal of Plant Resources
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    • v.19 no.6
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    • pp.706-715
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    • 2006
  • Nitrate reductase deficient (NR) mutant lines were selected indirectly by their resistance to 100mM chlorate in cell cultures of P. parviflora. A total of 585 chlorate resistant lines were confirmed by a second passage on a high concentration of chlorate. Frequency of spontaneous mutation was $9.7{\times}10^{-7}$ in 3 month old suspension-cultured cells, and in non-selective media containing amino acids as sole nitrogen source. The frequency of mutation could be increased up to 11-fold by culture for 12 months. Out of 40 randomly selected calli, 22 were fully deficient in NR. The rest of the clones contained a decreased level of NR activity. Further characterization was carried out in 13 mutant lines which were fully deficient in NR and in 5 mutant lines containing residual (0-7.0%) NR activity, as compared to wild-type cells cultured on the same medium. The $NR^-$ mutants were tentatively classified as defective in the NR apoenzyme (nia-type; 11 mutant lines including the 5 with residual NR activity) or in the molybdenum cofactor (cnx-type; 7 mutant lines) by the XDH activity. The cnx-type could be further classified into two groups. In one group (5 mutant lines) of these, the NR activity could be partially restored by nonphysiologically high (1.0mM) molybdate in the culture medium. Both types of $NR^-$ mutants were unable to grow on minimal medium containing nitrate as sole nitrogen source, but grew well on amino acids. They also proved to be extremely sensitive to the standard medium ($MSP_1$) containing nitrate and ammonium. Shoot regeneration was obtained only in the $NR^-$ mutants, which contained residual NR activity, but they so far have failed to grow into plants.