• Journal of the Korean Chemical Society
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• v.33 no.6
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• pp.633-643
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• 1989

The R$Rh_2(ap)_4$(2,2-trans) isomer (ap = 2-anilinopyridinate), which has two anilino nitrogens and two pyridyl nitrogens bound to each rhodium ion trans to their own kind, shows activation towards the one electron reduction of dioxygen at -0.40 V vs SCE. The ESR spectrum taken at 123 K proves the formation of a $[Rh_2(ap)_4(O_2)]$ ion with oxygen axially bound to one rhodium ion and the complex is at a RhⅡ2 oxidation state. The complex will form [$Rh_2(ap)_4(O_2)(CH_3CN)]^-$ in presence of $CH_3CN/CH_2Cl_2$ mixture without breaking the Rh-$O_2^-$ bond. When oxidized at -0.25 and 0.55 V, $[Rh_2(ap)_4(O_2)]$ will undergo two one electron oxidations to form $Rh_2(ap)_4(O_2)[Rh_2(ap)_4(O_2)]^+$. Both species have an axially bound superoxide ion but the former is at $Rh^{II}Rh^{III }$and the later at $Rh^{III}_2$ oxidation states. The ESR spetra and $CH_3CN$ addition study, on the other hand, show that the later complex is better described as $[Rh_{II}Rh^{III}(ap)_4(O_2)]^+$ with the odd electron localized on rhodium ion and the complex has an axially coordinated molecular oxygen. The electrochemical and ESR studies also show that the degree of dioxygen activation is a function of electrochemical redox potential.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.15-22
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• 2008

Four series (S, M, R, and W) of Alternaria longipes isolates were obtained based on consecutive selection with Dimethachlon (Dim) and ultraviolet irradiation. These isolates were then characterized according to their tolerance to Dim, sensitivity to osmotic stress, and phenotypic properties. All the selected Dim-resistant isolates showed a higher osmosensitivity than the parental strains, and the last generation was more resistant than the first generation in the M, R, and W series. In addition, the changes in the Dim resistance and osmotic sensitivity were not found to be directly correlated, and no distinct morphologic characteristics were found among the resistant and sensitive isolates, with the exception of the resistant isolate K-11. Thus, to investigate the molecular basis of the fungicide resistance, a group III two-component histidine kinase (HK) gene, AlHK1, was cloned from nineteen A. longipes isolates. AlHK1p was found to be comprised of a six 92-amino-acid repeat domain (AARD), HK domain, and response regulator domain, similar to the Os-1p from Neurospora crassa. A comparison of the nucleotide sequences of the AlHK1 gene from the Dim-sensitive and -resistant isolates revealed that all the resistant isolates contained a single-point mutation in the AARD of AlHK1p, with the exception of isolate K-11, where the AlHK1p contained a deletion of 107 amino acids. Moreover, the AlHK1p mutations in the isolates of each respective series involved the same amino acid substitution at the same site, although the resistance levels differed significantly in each series. Therefore, these findings suggested that a mutation in the AARD of AlHK1p was not the sole factor responsible for A. longipes resistance to dicarboximide fungicides.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.518-524
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• 2010

A mannanase gene (man26B) was obtained from a sea bacterium, Paenibacillus sp. BME-14, through the constructed genomic library and inverse PCR. The gene of man26B had an open reading frame of 1,428 bp that encoded a peptide of 475- amino acid residues with a calculated molecular mass of 53 kDa. Man26B possessed two domains, a carbohydrate binding module (CBM) belonging to family 6 and a family 26 catalytic domain (CD) of glycosyl hydrolases, which showed the highest homology to Cel44C of P. polymyxa (60% identity). The optimum pH and temperature for enzymatic activity of Man26B were 4.5 and $60^{\circ}C$, respectively. The activity of Man26B was not affected by $Mg^{2+}$ and $Co^{2+}$, but was inhibited by $Hg^{2+},\;Ca^{2+},\;Cu^{2+},\;Mn^{2+},\;K^+,\;Na^+$, and $\beta$-mercaptoethanol, and slightly enhanced by $Pb^{2+}$ and $Zn^{2+}$. EDTA did not affect the activity of Man26B, which indicates that it does not require divalent ions to function. Man26B showed a high specific activity for LBG and konjac glucomannan, with $K_m,\;V_{max}$, and $k_{cat}$ values of 3.80 mg/ml, 91.70 ${\mu}mol$/min/mg protein, and 77.08/s, respectively, being observed when LBG was the substrate. Furthermore, deletion of the CBM6 domain increased the enzyme stability while enabling it to retain 80% and 60% of its initial activity after treatment at $80^{\circ}C$ and $90^{\circ}C$ for 30 min, respectively. This finding will be useful in industrial applications of Man26B, because of the harsh circumstances associated with such processes.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.33-43
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• 2013

A bacterium producing a fibrinolytic enzyme was isolated from Cheonggukjang. The bacterium was identified as a strain of Bacillus amyloliquefaciens by 16S rDNA analysis and designated as B. amyloliquefaciens HC188. The optimum culture medium appeared to be one containing 0.5% (w/v) maltose and 0.5% (w/v) soytone. Bacterial growth in the optimal medium at $37^{\circ}C$ reached the stationary phase after 27 h of incubation and the fibrinolytic enzyme showed optimum activity at 24 h. The enzyme was purified by 20-80% ammonium sulfate precipitation, CM Sepharose fast flow ion exchange chromatography, and Sephacryl S-200HR column chromatography. Its specific activity was 38359.3 units/mg protein and the yield was 5.5% of the total activity of the crude extracts. The molecular weight was 24.7 kDa and the amino acids of the N-terminal sequence were AQSVPYGVSQIKAPA. The fibrinolytic enzyme activity had an optimum temperature of $40^{\circ}C$ and an optimum pH of 8.0, and the enzyme was stable in the ranges $20-40^{\circ}C$ and pH 6.0-8.0. Enzyme activity was increased by $Ca^{2+}$ and $Co^{2+}$ but inhibited by $Cu^{2+}$, EDTA, and PMSF. It is suggested that the purified enzyme is a metallo-serine protease.

• Microbiology and Biotechnology Letters
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• v.34 no.3
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• pp.196-203
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• 2006

Three slime-forming lactic acid bacteria were isolated from Kimchi and shown to produce viscous exopolysaccharides (EPS) in sucrose media. The isolated strains, GJ2, C3 and C11, were identified as Leuconostoc kimchii, Leuconostoc citreum and Leuconostoc mesenteroides, respectively, by examining their metabolic characteristics and determining their 16S rDNA sequences. Leu. kimchii GJ2, Leu. citreum C3 and Leu. mesenteroides C11 exhibited high viability (maintained initial viable cell count of $10^8$ CFU/ml) in 0.05 M sodium phosphate buffer (pH 3.0) for 2 h, in artificial gastric juice for 2 h and in 0.3% oxgall for 24 h. When tested, Leu. kimchii GJ2, in particular, displayed antimicrobial activity against pathogenic microorganisms. Leu. kimchii GJ2, Leu. citreum C3 and Leu. mesenteroides C11 produced 21.49 g/l, 16.46 g/l and 22.98 g/l EPS, respectively, in sucrose (5%) medium. The amount of purified EPS extracted from Leu. kimchii GJ2, Leu. citreum C3 and Leu. mesenteroides C11 was 14.61 g/l, 7.73 g/l and 4.77 g/l, respectively. Although the EPS produced by Leu. kimchii GJ2, Leu. citreum C3 and Leu. mesenteroides C11 differed in viscosity, TLC and HPLC analysis revealed that each contained only one type of monosaccharide, glucose. The average molecular mass of EPS produced by Leu. kimchii GJ2 was 306,606 Da.

• The Journal of Korean Society of Virology
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• v.28 no.3
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• pp.275-285
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• 1998

Based on the geographic range and distribution of its rodent reservoir host, the European common vole (Microtus arvalis), Tula virus is likely to be widespread throughout Eurasia. Tula virus-infected voles have been captured in Central Russia, Austria, Czech and Slovak Republics, and the former Yugoslavia. Although serologic evidence for Hantaan (HTN) or Seoul (SEO) virus infection can be found in the vast majority of the more than 300 cases of hemorrhagic fever with renal syndrome (HFRS) occurring annually in Korea, approximately 4% of Korean patients with HFRS show a more than 4-fold higher antibody titer to Puumala (PUU) virus than to HTN or SEO virus by double-sandwich IgM ELISA, suggesting the existence of pathogenic Puumala-related hantaviruses in Korea. To further define the geographic distribution and genetic diversity of Tula virus in Eurasia and to investigate the existence of previously unrecognized Microtus-borne hantavirus in Korea, arvicolid rodents were captured in Lodz, Poland in 1995 and in Yunchon-kun, Kyungki-do during April to May, 1998. In addition, sera from 18 Korean HFRS patients who showed higher (or the same) antibody titer to Tula virus than HTN and SEO viruses were examined for hantavirus RNA by RT-PCR. Hantaviral sequences were not detected in any of the 18 patients or in 35 reed voles (Microtus fortis) in Korea. Alignment and comparison of a 208-nucleotide region of the S segment, amplified from lung tissues of two hantavirus-seropositive Marvalis captured in Poland, revealed $80.8{\sim}83.2%$ sequence similarity, respectively, with Tula virus strains from Central Russia and the Czech and Slovak Republics. Phylogenetic analysis indicated that the newfound Tula virus strains from Poland were closely related to other Tula hantaviruses from Eurasia.

• Korean Journal of Plant Tissue Culture
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• v.28 no.5
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• pp.283-287
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• 2001

Differential display based on PCR was employed to identify genes expressed during tuber-developing stage of potato (Solanum tuberosum L. cv. Irish Cobbler). An eukaryotic initiation factor 5A (eIF-5A) clone isolated from a cDNA library constructed with developing micro-tuber using a probe of PCR fragment. We isolated three positive clones and ore of them contained open reading frame. This clone revealed high sequence similarity to tomato eIF 5A cDNA. At the DNA level, there is 94.8% identity with the tomato eIF-5A4, whereas at the protein level there is a high identity with 97.5%. The potato eIF 5A clone is 716 bp in length and contains a single open reading frame from 57 to 539 bp, a 56 bp 5'-untranslated region and a 177 bp 3'-untranslated region. The deduced protein composed of 160 amino acid residues, with a predicted molecular mass of 17.4 kD and an estimated pl of 5.5. The sequence of 12 (STSKTGKHGHAK) amino acids among eIF-5A proteins is perfectly conserved from yeast to human. That sequence in potato eIF-5A protein is also conserved at position 46 to 57 amino acid. This region embeds the post-translational modification site of the lysine residue (at the seventh K) to hypusine that is crucial to eIF-5A activity. The northern blot analysis of eIF5A has shown abundant expression, mainly in flower organs (stamen, ovary, petal, sepal), fruit and stolen.

• The Plant Pathology Journal
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• v.18 no.5
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• pp.259-265
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• 2002

Apple mosaic virus (ApMV), a member of the genus Ilarvirus, was detected and isolated from diseased 'Fuji' apple (Malus domestica) in Korea. The coat protein (CP) genes of two ApMV strains, denoted as ApMV-Kl and ApMV-K2, were amplified by using the reverse transcription and polymerase chain reaction (RT-PCR) and were analyzed thereafter. The objectives were to define the molecular variability of genomic information of ApMV found in Korea and to develop virus-derived resistant gene source for making virus-resistant trans-genic apple. RT-PCR amplicons for the APMVS were cloned and their nucleotide sequences were determined. The CPs of ApMV-Kl and ApMV-K2 consisted of 222 and 232 amino acid residues, respectively. The identities of the CPs of the two Korean APMVS were 93.1% and 85.6% at the nucleotide and amino acid sequences, respectively. The CP of ApMV-Kl showed 46.1-100% and 43.2-100% identities to eight different ApMV strains at the nucleotide and amino acid levels, respectively. When ApMV-PV32 strain was not included in the analysis, ApMV strains shared over 83.0% and 78.6% homologies at the nucleotide and amino acid levels, respectively. ApMV strains showed heterogeneity in CP size and sequence variability. Most of the amino acid residue differences were located at the N-termini of the strains of ApMV, whereas, the middle regions and C-termini were remarkably conserved. The APMVS were 17.(1-54.5% identical with three other species of the genus Ilarviyus. ApMV strains can be classified into three subgroups (subgroups I, II, and III) based on the phylogenetic analysis of CP gene in both nucleotide and amino acid levels. Interestingly, all the strains of subgroup I were isolated from apple plants, while the strains of subgroups II and III were originated from peach, hop, or pear, The results suggest that ApMV strains co-evolved with their host plants, which may have resulted in the CP heterogeneity.

• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.204-210
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• 1997

Zeolite 4A-impregnated complex molecular sieve was prepared by hydrothermal reaction after aluminosilicate gel was penetrated into the pore of activated carbon granule. The crystals of zeolite 4A mainly were formed in the macropore of activated carbon, and their average diameter is $0.8{\mu}m$. The pore volume of activated carbon granule is $0.67m{\ell}/g$, and the pore volume of the sample including 21.6wt% of zeolite 4A crystal is $0.41m{\ell}/g$ decreasing the pore volume by 40% due to the crystallization of zeolite 4A crystals on the internal surface of activated carbon. The calcium ion exchange capacity of zeolite 4A-impregnated sample is 320mg $CaCO_3/g$ zeolite, and this value is almost the same as that of zeolite 4A powder. The crystal of zeolite 4A was not separated from the support of activated carbon granule in the course of ultrasonic dispersion. The adsorption isotherm of water on zeolite 4A-impregnated sample shows the intermediate shape between types, I and III. In addition, zeolite 4A-impregnated sample shows the hydrophilic and hydrophobic properties simultaneously.

• Horticultural Science & Technology
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• v.35 no.3
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• pp.333-343
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• 2017

Bloomless cucumber fruits are commercially produced by grafting onto the pumpkin stocks (Cucurbita moschata) to restricted silicon ($SiO_2$) absorption. Inhibition of silicon absorption in bloomless stocks is conferred by a mutant allele of the CmLsi1 homologous to Lsi1 in rice. In this study, we characterized the Lsi1 homologs in pumpkin (C. moschata) and its cold-tolerant wild relative C. ficifolia ('Heukjong') in order to develop a DNA marker for selecting a bloomless trait and to establish the molecular basis for breeding bloomless stock cultivars of C. ficifolia. A Cleaved amplified polymorphic sequence (CAPS) marker (CM1-CAPS) was designed based on a non-sysnonymous single nucleotide polymorphism (SNP, C>T) of the CmLsi1 mutant-type allele, and its applicability for Marker-assisted selection (MAS) was confirmed by evaluating three bloom and five bloomless pumpkin stock cultivars. Quantitative RT-PCR of the CmLsi1 for these stock cultivers implied that expression level of the CmLsi1 gene does not appear to be associated with the bloom/bloomless trait and may differ depending on plant species and tissues. A full length cDNA of the Lsi1 homolog [named CfLsi1($B^+$)] of 'Heukjong' (C. ficifolia), was cloned and sequence comparison between CmLsi1($B^+$) and CfLsi1($B^+$) revealed that there exists total 24 SNPs, of which three were non-synonymous. Phylogenetic analysis of CfLsi1($B^+$) and Lsi1 homologs further revealed that CfLsi1($B^+$) is closesly related to Nodulin 26-like intrinsic proteins (NIPs) and most similar to CpNIP1 of C. pepo than C. moschata.