• Journal of Microbiology and Biotechnology
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• v.8 no.1
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• pp.74-80
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• 1998

CS-2l lymphoma cells that preferentially metastasize to lymph nodes after s.c. inoculation into BALB/c mice were grown in vitro in the presence of CA- 12 stromal cells isolated from lymph nodes. In order to obtain fundamental data on the identification and characterization of the soluble factors produced by CA-12 stromal cells, the conditioned medium of CA-12 stromal cells that inhibited apoptosis of CS-21 cells was examined. Various analytical treatments revealed that the soluble factors in CA-12 conditioned medium are very sensitive to heat treatment and trypsinization. Moreover CA-12 conditioned medium has an affinity with heparin but not with Con-A. In addition to these, the activity of CA-12 conditioned medium was blocked by H-7, a PKC inhibitor, but the conditioned medium could not induce the differentiation of thymocytes. We concluded that CA-12 conditioned medium contains stromal cell-derived apoptosis-inhibitory molecules that play an important role in proliferation of CS-2l cells by suppressing cell apoptosis.

• Journal of Microbiology and Biotechnology
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• v.12 no.1
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• pp.96-105
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• 2002

A bacteriocin-producing strain identified as Pediococcus acidilactici was isolated from kimchi. The bacteriocin was identified to belong to the pediocin family and exhibited bactericidal activity against most Gram-positive bacteria as well as some Gram-negative bacteria. The bacteriocin was stable up to $80^{\circ}C with wide pH ranges (5.0-10.0). The bactericidal activity remained unchanged after treatment with nonproteolytic enzymes such as nuclease and ${\alpha}$-amylase, however, it was destroyed after treatment with protease. The bacteriocin was effectively extracted by the pH-mediated adsorption-desorption method and purified effectively by semi-preparative RP-HPLC. The molecular weight of the bacteriocin was 4,622, as determined by electrospray mass spectrometry. The amino acid sequence consisted of 44 amino acid residues with four cysteines. The high solubility and pH stability of the isolated pediocin provide definite advantages over nisin and other bacteriocins in regards to its potential applications.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.8-13
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• 1991

Bacteriocin-producing microorganisms were screened from raw milk and tested their antimicrobial activities against Lactobacillus plantarum ATCC 8014 as target organism, Antimicrobial substances isolated showed broad antimicrobial spectra against Gram positives and negatives. Strain 1112-1 was selected as a test organism due to its highest antimicrobial activity among the isolates. Antimicrobial substance produced by 1112-1 completely suppressed the growth of Lactobacillus plantarum at 230 IUIml and showed 11% growth inhibition of E. coli at 500 IUIrnl level. The antimicrobial substance was found to be proteinaceous material which was inactivated by carboxypeptidase, elastase, alpha amylase, amyloglucosidase, pronase, protease IV, alpha chymotrypsin, ficin, cellulase, phosphatase and lipase. The molecular weight was estimated by SDS-PAGE as 5,900. The isolate 1112-1 was identified as one of the related strains of Lactococcus sp. The strain was different from Lactococcus lactis in the following characteristics: late positive in maltose and sucrose fermentation; positive in mannitol and salicin fermentation; negative in lactose fermentation.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.73-79
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• 1994

The optimum cultural temperature and time for the pullulanase production by Bacillus cereus subsp. mycoides were 35$\circ $C and 48 hrs, respectively. The addition of egg albumin and casein to the basal medium increased the enzyme production. The enzyme was purified by ammonium sulfate fractionation and DEAE-cellulose column chromatography. specific activity of the purified enzyme was 82.37 U/mg protein and yield of theenzyume activity was 62.1%. The purified enzuyme showed a single band on ployacrylamide disc gel electrophoresis and its molecular weight was estimated to be 66.,000 by SDS-polyacrylamide disc gel electrophoresis. The isoelcular point for the purified enzyme was pH 5.0. The optimum temperature and pH were 50$\circ $C and pH 6.5, respectively. The purified enzyme was stable below 40$\circ $C and in the pH range of 6.5~10.0 The pullulanase activity was greatly inhited by Ag$^{+}$, Hg$^{2+}$ and EDTA, and its heat stability was increased by the addition of Ca$^{2+}$. The tydrolysis product with the enzyme on pullulan was maltotriose.

• Microbiology and Biotechnology Letters
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• v.34 no.4
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• pp.289-298
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• 2006

3',5'-cyclic adenosine monophosphate (cAMP) is an important molecule, which mediates diverse cellular processes. For example, it is involved in regulation of sugar uptake/catabolism, DNA replication, cell division, and motility in various acterial species. In addition, cAMP is one of the critical regulators for syntheses of virulence factors in many pathogenic bacteria. It is believed that cAMP acts as a signal for environmental changes as well as a regulatory factor for gene expressions. Therefore, intracellular concentration of cAMP is finely modulated by according to its rates of synthesis (by adenylate cyclase), excretion, and degradation (by cAMP phosphodiesterase). In the present review, we discuss the bacterial physiological characteristics governed by CAMP and the molecular mechanisms for gene regulation by cAMP. Furthermore, the effect of cAMP on phosphotransferase system is addressed.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.383-390
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• 2010

A newly isolated active producer of raw-starch-digesting amyloytic enzymes, Rhizopus microsporus var. chinensis CICIM-CU F0088, was screened and identified by morphological characteristics and molecular phylogenetic analyses. This fungus was isolated from the soil of Chinese glue pudding mill, and produced high levels of amylolytic activity under solid-state fermentation with supplementation of starch and wheat bran. Results of thin-layer chromatography showed there are two kinds of amyloytic enzymes formed by this strain, including one $\alpha$-amylase and two glucoamylases. It was found in the electron microscope experiments that the two glucoamylases can digest raw corn starch and have an optimal temperature of $70^{\circ}C$. These results signified that amyloytic enzymes secreted by strain Rhizopus microsporus var. chinensis CICIM-CU F0088 were types of thermostable amyloytic enzymes and able to digest raw corn starch.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.166-167
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• 2006

Dendrimers represent a new class of synthetic macromolecules characterized by a regularly branched treelike structure. Multiple branching yields a large number of chain ends that distinguish dendrimers from conventional star-like polymers and microgels. The azobenzene dendrimer is one of the dendrimeric macromolecules that include the azo-group exhibiting a photochromic character. Due to the presence of the charge transfer element of the azo-group and its rod-shaped structure, these compounds are expected to have potential interest in electronics and photoelectronics, especially in nonlinear optics. In the present paper, we give pressure stimulation to organic thin films and detect the induced displacement current. Functional photoisometrization organic molecular the photo-stimulus to organic monomolecular L-films and LB films of dendrimer and 8A5H were performed. The 8A5H organic monolayer in case of pressure stimulus occurred that positive course but in case of the photo-stimulus compared positive and negative. It is assumed that generation forms of displacement current were measured when photo-stimulus for Impression.

• YAKHAK HOEJI
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• v.41 no.3
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• pp.359-364
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• 1997

Resistance gene mphK was cloned from Escherichia coli 209K strain which is highly resistant to erythromycin (EM). By using the cloned plasmid pGE64, E. coli NM522 was transformed. The comparison of macrolide-phosphotransferase K [MPH(K)] activity between E. coli 209K and E. coli NM522(pGE64) showed that the total enzyme activity of MN522(pGE64) was fifty-fole higher than that of 209K. To identify characteristics of MPH(K) more precisely. MPH(K) was isolated and purified from the NM522 (pGE64). The final purification f MPH(K) through several stages of purification process was 89 fole and the overall recovery was 11%. This enzyme was monomer with the molecular weight of 34 kDa and its isoelectric point (pI) was 5.0. The optimal pH and temperature for activity were 8.0 and $40^{\circ}C$, respectively.

• Mycobiology
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• v.38 no.4
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• pp.310-315
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• 2010

Agrocybe aegerita is an important mushroom cultivated in Korea, with good feel and a peculiar fragrance. A. aegerita can be cultivated throughout the year using culture bottles but is more susceptible to contamination than other mushrooms. Twenty-two pathogens were isolated from the fruiting bodies and compost of A. aegerita, and seven isolates were isolated from Pleurotus ostreatus to compare with the A. aegerita isolates, collected from Gimje, Iksan, Gunsan of Chonbuk, and Chilgok of Gyeongbuk Province in 2009. These isolates were identified based on morphological and molecular characteristics. Of the 29 isolates, 26 were identified as Trichoderma spp. and the remaining three were Aspergillus spp., Mucor spp., and Penicillium spp. A phylogenetic analysis revealed that the 26 isolates of Trichoderma were divided into four taxa, namely T. harzianum, T. pleuroticola, T. longibrachiatum, and T. atroviride. Among the Trichoderma spp., 16 isolates (55.2%) were identified as T. harzianum, six as T. pleuroticola (20.7%), two as T. longibrachiatum, and the remaining two were T. atroviride.

• Mycobiology
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• v.44 no.3
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• pp.187-190
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• 2016

In July 2015, diseased leaves of black chokeberry (Aronia melanocarpa) were observed in Danyang and Gochang, Korea. The symptoms appeared as circular or irregular brown leaf spots, from which Alternaria tenuissima was isolated. The isolates were cultured on potato dextrose agar, and their morphological characteristics were observed under a light microscope. The colonies were whitish to ash colored. The pathogenicity test on healthy black chokeberry leaves produced circular brown spots, in line with the original symptoms. Molecular analyses of the ITS, GPD, RPB2, and TEF genes were conducted to confirm the identity of the pathogen. The phylogeny of the multi-gene sequences indicated that the causal agent was A. tenuissima. This study is the first report of A. tenuissima leaf spot on black chokeberry (A. melanocarpa).