• Title/Summary/Keyword: R2S

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Synthesis and Phytotoxic Activities of (8S, 9S, 11R)-(-)-Monocerin and (9S, 11R)-(+)-Fusarentin 4, 5-dimethyl ether ((8S, 9S, 11R)-(-)-Monocerin and (9S, 11R)-(+)-Fusarentin 4, 5-dimethyl ether의 합성과 생리활성)

  • Ko, Byoung-Seob
    • Applied Biological Chemistry
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    • v.37 no.5
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    • pp.402-408
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    • 1994
  • For the examination of the role of monocerin(1) on the biological activity, (8S, 9S, 11R)-(-)-monocerin(20) and (9S, 11R)-(+)-fusarentin 4, 5-dimethyl ether(19) were synthesized by a condensation of the benzylic anion of ethyl 2, 3, 4-trimethoxy-6-methylbenzoate(16) with modifyed (R)-ethyl 3-hydroxyhexanoate (9). In a key step, bioreduction with active dried baker's yeast in organic solvent system was employed to get a chiral aldehyde 12. Their phytotoxic activities were tested on rice seedlings and lettuce seeds.

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Cloning of 17S-Ribosomal RNA Gene from the Hygromycin Resistant Tetrahymena thermophila (Hygromycin내성 Tetrahymena thermophila의 17S-Ribosomal RNA유전자의 Cloning)

  • 홍용기
    • Microbiology and Biotechnology Letters
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    • v.14 no.2
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    • pp.133-137
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    • 1986
  • 17S-ribosomal RNA gene from the hygromycin resistant protozoan Tetrahymena thermophila hmr 3 was cloned on E. coli vector pBR 322 as part of study to work the 17S-rRNA structure and the mechanism of hygromycin resistance. The 17S-rDNA was inserted into the Hind 111 site of pBR 322. The clones having recombinant plasmid were selected by the method of colony hybridization with a 17S-rDNA probe of wild type B1868. The orientation of 17S-rDNA insert was located near the tetracycline resistant gene of pBR 322 in a clone 5-19 with the recombinant plasmid.

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Ethanol Production from Raw Starch by Co-Immobilized Mixed Rhizopus japonicus and zymomonas mobilis (Rhizopus japonicus와 Zymomonas mobilis의 혼합고정화 배양계에 의한 생전분으로부터 에탄올 생산)

  • 최수철;이상원;박석규;성찬기;손봉수;성낙계
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.25 no.4
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    • pp.708-714
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    • 1996
  • Ethanol production from raw starch was performed using the co-immobilized culture system of Rhizopu japonicus and zymomonas mobilis(R-Z). Glucose Production in immobilized R. japonicus culture was 2-fold higher than that in free cell culture. Ethanol production was 1.67g/L(Yp/s, 0.094) and 6.549/L(Yp/s, 0.38) in R-Z and R-Z 24 culture system, respectively. R-Z system was modified and designated as R-Z 24 system by replacing cotton plug with silicon check valve after 24h fermentation with R-Z system. Optimal substrate concentration for ethanol production in batch culture was 5%(w/v) and ethanol concentration produced was 15.02g/L(Yp/s, 0.36). Ethanol yield(Yp/s, 0.38) in fed-batch culture of 5 times with 2%(w/v) substrate was equal to that in batch culture of 2%(w/v) substrate.

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Synthesis and Magnetic Relaxation Properties of Paramagnetic Gd-complexes of New DTPA-bis-amides. The X-ray Crystal Structure of [Gd(L)(H2O)]·3H2O (L = DTPA-bis(4-carboxylicphenyl)amide)

  • Dutta, Sujit;Kim, Suk-Kyung;Lee, Eun-Jung;Kim, Tae-Jeong;Kang, Duk-Sik;Chang, Yong-min;Kang, Sang-Ook;Han, Won-Sik
    • Bulletin of the Korean Chemical Society
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    • v.27 no.7
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    • pp.1038-1042
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    • 2006
  • A new type of DTPA-bis-amides (L1-L4) and their Gd(III)-complexes of the type $[Gd(L)(H_2O)]{\cdot}nH_2O$ (5: L1; 6: L2; 7: L3; 8: L4) have been prepared and characterized by analytical and spectroscopic techniques. The X-ray crystal structure of 8 has been determined for structural confirmation. The coordination geometry adopts a tricapped trigonal prism geometry with L4 acting as a chelate octadentate and a water molecule in the coordination sphere. Crystals are monoclinic, $P2_1$, a = 14.468(3), b = 19.235(4), c = 13.527(2) $\AA$ $\beta$ = $107.245(3)^{\circ}$, V = 3595.2(11) $\AA^3$, Z = 4, $D_{calc}$ = 1.570. Significant increases in relaxivities are observed with 6 and 7 as compared with that of $Omniscan^{(R)}$, a commercial MR agent: R1 = 12.46 $mM^{-1}\;s^{-1}$, R2 = 8.76 $mM^{-1}\;s^{-1}$ for 6; R1 = 12.77 nm-1 s-1, R2 = 7.60 mM-1 s-1 for 7; R1 = 4.9 $mM^{-1}\;s^{-1}$, R2 = 4.8 $mm^{-1}\;s^{-1}$ for $Omniscan^{(R)}$. In the case of 5, however, both R1 and R2 are found to be lower to show 2.09 $mM^{-1}\;s^{-1}$, and 1.82 $mM^{-1}\;s^{-1}$, respectively.

An evaluation of empirical regression models for predicting temporal variations in soil respiration in a cool-temperate deciduous broad-leaved forest

  • Lee, Na-Yeon
    • Journal of Ecology and Environment
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    • v.33 no.2
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    • pp.165-173
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    • 2010
  • Soil respiration ($R_S$) is a critical component of the annual carbon balance of forests, but few studies thus far have attempted to evaluate empirical regression models in $R_S$. The principal objectives of this study were to evaluate the relationship between $R_S$ rates and soil temperature (ST) and soil water content (SWC) in soil from a cool-temperate deciduous broad-leaved forest, and to evaluate empirical regression models for the prediction of $R_S$ using ST and SWC. We have been measuring $R_S$, using an open-flow gas-exchange system with an infrared gas analyzer during the snowfree season from 1999 to 2001 at the Takayama Forest, Japan. To evaluate the empirical regression models used for the prediction of $R_S$, we compared a simple exponential regression (flux = $ae^{bt}$Eq. [1]) and two polynomial multiple-regression models (flux = $ae^{bt}{\times}({\theta}{\nu}-c){\times}(d-{\theta}{\nu})^f:$ Eq. [2] and flux = $ae^{bt}{\times}(1-(1-({\theta}{\nu}/c))^2)$: Eq. [3]) that included two variables (ST: t and SWC: ${\theta}{\nu}$) and that utilized hourly data for $R_S$. In general, daily mean $R_S$ rates were positively well-correlated with ST, but no significant correlations were observed with any significant frequency between the ST and $R_S$ rates on periods of a day based on the hourly $R_S$ data. Eq. (2) has many more site-specific parameters than Eq. (3) and resulted in some significant underestimation. The empirical regression, Eq. (3) was best explained by temporal variations, as it provided a more unbiased fit to the data compared to Eq. (2). The Eq. (3) (ST $\times$ SWC function) also increased the predictive ability as compared to Eq. (1) (only ST exponential function), increasing the $R^2$ from 0.71 to 0.78.

BOUNDS ON PROBABILITY FOR THE OCCURRENCE OF EXACTLY r, t OUT OF m, n EVENTS

  • Lee, Min-Young
    • Communications of the Korean Mathematical Society
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    • v.12 no.2
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    • pp.393-401
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    • 1997
  • Let $A_1,A_2,\cdots,A_m$ and $B_1,B_2,\cdots,B_n$ be two sequences of events on a given probability space. Let $X_m$ and $Y_n$, respectively, be the number of those $A_i$ and $B_j$, which occur we establish new upper and lower bounds on the probability $P(X=r, Y=t)$ which improve upper bounds and classical lower bounds in terms of the bivariate binomial moment $S_{r,t},S_{r+1,t},S_{r,t+1}$ and $S_{r+1,t+1}$.

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Nucleotide sequence analysis of the 5S ribosomal RNA gene of the mushroom tricholoma matsutake

  • Hwang, Seon-Kap;Kim, Jong-Guk
    • Journal of Microbiology
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    • v.33 no.2
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    • pp.136-141
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    • 1995
  • From a cluster of structural rRNA genes which has previsouly been cloned (Hwang and Kim, in submission; J. Microbiol. Biotechnol.), a 1.0-kb Eco RI fragment of DNA which shows significant homology to the 25S and rRNA s of Tricholoma matsutake was used for sequence analysis. Nucleotide sequence was bidirectionally determined using delection series of the DNA fragment. Comparing the resultant 1016-base sequence with sequences in the database, both the 3'end of 25S-rRNA gene and 5S rRNA gene were searched. The 5S rRNA gene is 118-bp in length and is located 158-bp downstream of 3'end of the 25S rRNA gene. IGSI and IGS2 (partial) sequences are also contained in the fragment. Multiple alignment of the 5S rRNA sequences was carried out with 5S rRNA sequences from some members of the subdivision Basidiomycotina obtained from the database. Polygenetic analysis with distance matrix established by Kimura's 2-parameter method and phylogenetic tree by UPGMA method proposed that T. matsutake is closely related to efibulobasidium allbescens. Secondary structure of 5S rRNA was also hypothesized to show similar topology with its generally accepted eukaryotic counterpart.

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