• Journal of the Chungcheong Mathematical Society
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• v.31 no.4
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• pp.475-486
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• 2018

We study free actions of finite nonabelian groups on 3-dimensional nilmanifolds with the first homology ${\mathbb{Z}}^2{\bigoplus}{\mathbb{Z}}_2$ which yield an orbit manifold reversing fiber orientation, up to topological conjugacy. We show that those nonabelian groups are $D_4$(the dihedral group), $Q_8$(the quaternion group), and $C_8.C_4$(the $1^{st}$ non-split extension by $C_8$ of $C_4$ acting via $C_4/C_2=C_2$).

• Journal of Microbiology and Biotechnology
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• v.22 no.8
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• pp.1044-1053
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• 2012

The gene encoding an esterase enzyme was cloned from a metagenomic library of cow rumen bacteria. The esterase gene (est5S) was 1,026 bp in length, encoding a protein of 366 amino acid residues with a calculated molecular mass of 40,168 Da. The molecular mass of the enzyme was estimated to be 40,000 Da. The Est5S protein contains the Gly-X-Ser-X-Gly motif found in most bacterial and eukaryotic serine hydrolases. However, the Asp or Glu necessary for the catalytic triad [Ser-Asp-(Glu)-His] was not present, indicating Est5S represents a novel member of the GHSQG family of esterolytic enzymes. BlastP in the NCBI database analysis of Est5S revealed homology to hypothetical proteins and it had no homology to previous known lipases and esterases. Est5S was optimally active at pH 7.0 and $40^{\circ}C$. Among the p-nitrophenyl acylesters tested, high enzymatic activities were observed on the short-chain p-nitrophenyl acylesters, such as p-nitrophenyl acetate, etc. The conserved serine residue ($Ser_{190}$) was shown to be important for Est5S activity. The primers that amplified the est5S gene did not show any relative band with 49 species of culturable rumen bacteria. This implies that a new group esterase gene, est5S, may have come from a noncultured cow rumen bacterium.

• Journal of the Korean Mathematical Society
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• v.43 no.5
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• pp.1047-1063
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• 2006

Let $\varepsilon_#(X)$ be the subgroups of $\varepsilon(X)$ consisting of homotopy classes of self-homotopy equivalences that fix homotopy groups through the dimension of X and $\varepsilon_*(X) $ be the subgroup of $\varepsilon(X)$ that fix homology groups for all dimension. In this paper, we establish some connections between the homotopy group of X and the subgroup $\varepsilon_#(X)\cap\varepsilon_*(X)\;of\;\varepsilon(X)$. We also give some relations between $\pi_n(W)$, as well as a generalized Gottlieb group $G_n^f(W,X)$, and a subset $M_{#N}^f(X,W)$ of [X, W]. Finally we establish a connection between the coGottlieb group of X and the subgroup of $\varepsilon(X)$ consisting of homotopy classes of self-homotopy equivalences that fix cohomology groups.

• Journal of the Chungcheong Mathematical Society
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• v.33 no.1
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• pp.113-132
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• 2020

We show that if a finite group G acts freely with homotopically trivial translations on a 3-dimensional nilmanifold 𝓝_p with the first homology ℤ² ⊕ ℤ_p, then either G is cyclic or there exist finite nonabelian groups acting freely on 𝓝_p which yield orbit manifolds homeomorphic to 𝓝/𝜋₃ or 𝓝/𝜋₄.

• Bulletin of the Korean Mathematical Society
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• v.38 no.4
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• pp.741-751
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• 2001

In this paper when $(M, \omega)$ is a compact weakly exact symplectic manifold with nonempty boundary satisfying $c_1｜{\pi}_2(M)$ = 0, we construct an action spectrum bundle over the group of Hamil-tonian diffeomorphisms of the manifold M generated by the time-dependent Hamiltonian vector fields, whose fibre is nowhere dense and invariant under symplectic conjugation.

• Microbiology and Biotechnology Letters
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• v.46 no.1
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• pp.59-67
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• 2018

A xylanolytic and cellulolytic anaerobic bacterium strain CtC72 was isolated from cattle rumen liquor. Phylogenetic analysis of 16S rRNA gene sequences revealed that strain CtC72 shared only 97.78% homology with its nearest phylogenetic affiliate Actinomyces ruminicola, showing its novelty. The strain could grow on medium containing xylan, carboxymethyl cellulose and avicel producing $CO_2$, acetate, and ethanol as major fermentation products. The whole genome analysis of the strain CtC72 exhibited a broad range of carbohydrate-active enzymes required for the breakdown and utilization of lignocellulosic biomass. Genes related to the production of ethanol and stress tolerance were also detected. Further there were several unique genes in CtC72 for chitin degradation, pectin utilization, sugar utilization, and stress response in comparison with Actinomyces ruminicola. The results show that the strain CtC72, a putative novel bacterium can be used for lignocellulosic biomass based biotechnological applications.

• Communications of the Korean Mathematical Society
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• v.9 no.4
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• pp.933-944
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• 1994

Let $\pi : P \to S^4$ be a principal G-bundle over $S^4$ whose the structure group G is a compact, connected, simple Lie group. Since $\pi_3(G) = \pi_4 (BG) = Z$, we can classify the principal bundle $P_k$ over $S^4$ by the map $S^4 \to BG$ of degree k. Atiyah and Jones [2] showed that $C_k = A_k/g^b_k$ is homotopy equivalent to $\Omega^3_k G \simeq \Omega^4_k BG$ where $A_k$ is the space of the all connections in $P_k$ and $g^b_k$ is the based gauge group which consists of all base point preserving automorphisms on $P_k$. Here $\Omega^nX$ is the space of all base-point preserving continuous map from $S^n$ to X. Let $M_k$ be the space of based gauge equivalence classes of all connections in $P_k$ satisfying the Yang-Mills self-duality equations, which we call the moduli space of G instantons.

• Journal of Microbiology
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• v.39 no.1
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• pp.11-16
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• 2001

Tentative identification of Leuconostoc lactis IH23 isolated from kimchi (a fermented vegetable product) has been described previously with 16S rDNA sequencing (Choi, 1., M. Sc. Thesis Inha Univ.1999). This strain produced the slime identified as dextran based on IR, $\^$13/C- and $^1$H-NMR spectroscopic results. Further study proved that the isolate IH23 belongs to a homogeneous genetic group with L. lactis DSM 20202$\^$T/ and L. argentinum DSM 8581$\^$T/. The results showed DNA-DNA homology of 99-100%, 16S rDNA gene sequence similarity (97.7% ), and a phylogenetic relationship although L. argentinum DSM 8581$\^$T/ had lower homology (80-91%). These data indicate that L. argentinum DSM 8581$\^$T/ and the isolate IH23 belong to an identical species with L. lactis DSM 20202$\^$T/at the genetic level, although in carbohydrate fermentation, the isolate IH23 was mast closely related to L. argentinum DSM 8581$\^$T/ and quite different from L. lactis DSM 20202$\^$T/. Here we first report the isolation of consistent phenotypic variation in Leuconostoc lactis. We also emphasize that the nomenclature of subspecies needs to be differentiated into the three strains mentioned above in Leuconostoc lactis.

• International Journal of Industrial Entomology and Biomaterials
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• v.39 no.2
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• pp.67-73
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• 2019

The genomic structure of the Cu/Zn superoxide dismutase (SOD1) gene from the entomopathogenic fungus, Cordyceps pruinosa was characterized. The SOD1 gene of C. pruinosa spans 947 nucleotides and consisted of four exons encoding for 154 amino acids and three introns. Four exons of the SOD1 gene are composed of 13, 331, 97 and 20 nucleotides respectively. Homology search of amino acid sequences of the SOD1 gene of C. pruinosa with another 13 fungi species showed higher sequence similarity of 69% ~ 95% and had the most highest sequence identity of 95% with Beauveria bassiana and Cordyceps militaris, which can easely infect domesticated Bombyx mori and another wild lepidopteran species in artificial or natual manner of infection. This SOD1 gene sequence showed copper, zinc and beta-barrel fold sites. Homology search showed that the Cu/Zn SOD1 gene from the entomopathogenic fungus, C. pruinosa is an orthologous gene homolog present in different species of organism whose ancestor predates the split between the relating species. In addition, C. pruinosa SOD1 gene is placed together within the ascomycetes group of fungal clade. From these results it is concluded that C. pruinosa SOD1 gene is orthologous gene having the same or very similar functions with a common evolutionary ancestor.

• Korean Journal of Microbiology
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• v.30 no.5
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• pp.397-402
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• 1992

The cDNA of RNA segment coding for VP7 of human rotavirus isolated from patient's stool at Seoul area was synthesized, amplified by polymerase chain reaction, field in with Klenow fragment of DNA polymerase I and cloned into pUC19. The cDNA sequence was determined and compared with that of VP7 coding RNA segments of group A rotaviruses isolates in foreign country. Over 90% sequence homology was found with serotyppe I sepcific WA1 and RE9 strains. Comparative analysis of the deduced amino acid sequences within the two variable regions (amino acid residue 87 through 101 and 208 through 221) with WA1 and RE9 strains also showed high degree of sequence similarity with each other.