• 한국미생물·생명공학회지
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• 제48권1호
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• pp.64-71
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• 2020

A total of 262 bacterial strains were isolated from clay minerals, bentonite and zeolite, in Gyeongsangbukdo, Republic of Korea, and their hydrolytic enzyme activities were analyzed. Most of the isolated strains belonged to Micrococcales and Bacillales order. Of strains, 96 strains produced α-amylase activity, 42 strains showed cellulase activity, 111 strains had pectinase activity, and 70 strains showed protease activity. Among them, 177 isolates exhibited one or more of the hydrolytic enzyme activities and in particular Bacillus cereus MBLB1321, B. albus MBLB1326 and KIGAM017, B. mobilis MBLB1328, MBLB1329 and MBLB1330 showed all of the enzyme activities. These results demonstrate the diversity of functional Bacillus species in clay minerals as vital sources for the discovery of industrially valuable hydrolytic enzymes, which have a great commercial prospect in various bio-industrial applications.

• Mycobiology
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• 제38권1호
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• pp.26-32
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• 2010

The cyclic AMP (cAMP) pathway plays a major role in growth, sexual differentiation, and virulence factor synthesis of pathogenic fungi. In Cryptococcus neoformans, perturbation of the cAMP pathway, such as a deletion in the gene encoding adenylyl cyclase (CAC1), causes defects in the production of virulence factors, including capsule and melanin production, as well as mating. Previously, we performed a comparative transcriptome analysis of the Ras- and cAMP- pathway mutants, which revealed 163 potential cAMP-regulated genes (38 genes at a 2-fold cutoff). The present study characterized the role of one of the cAMP pathway-dependent genes (serotype A identification number CNAG_ 06576.2). The expression patterns were confirmed by Northern blot analysis and the gene was designated cAMP-regulated gene 1 (CAR1). Interestingly, deletion of CAR1 did not affect biosynthesis of any virulence factors and the mating process, unlike the cAMP-signaling deficient cac1$\Delta$ mutant. Furthermore, the car1$\Delta$ mutant exhibited wild-type levels of the stress-response phenotype against diverse environmental cues, indicating that Car1, albeit regulated by the cAMP-pathway, is not essential to confer a cAMP-dependent phenotype in C. neoformans.

• BMB Reports
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• 제43권5호
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• pp.375-381
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• 2010

In this study, the cDNA library of Chang-liver cells was immunoscreened using common ADAMs antibody to obtain ADAM related genes. We found one positive clone that was confirmed as a new gene by Blast, which is an uncharacterized helical and coil protein and processes protease activity, and named protease-related protein 1 (ARP1). The submitted GenBank accession number is AY078070. Molecular characterizations of ARP1 were analyzed with appropriate bioinformatics software. To analyse its expression and function, ARP1 was subcloned into glutathione S-transferase fusion plasmid pGEX-2T and expressed by E. coli system. The in vitro expression product of ARP1 was recognized by common ADAMs antibody with western blot. Interestingly, ARP1 cleaves gelatine at pH9.5, which suggests it is an alkaline protease. Semi-quantitative RT-PCR result indicates that ARP1 mRNA is strongly transcribed in the liver and the treated Chang-liver cells.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.422-422
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• 2009

Photocurable inorganic-organic hybrid materials were prepared from colloidal-silica nanoparticles synthesized through the solgel process and using acryl resin. The synthesized colloidal-silica nanoparticles had uniform diameters of around 20 nm, and they were organically modified, using methyl and methacryl functional silanes, for efficient hybridization with acryl resin. The organically modified and stabilized colloidal-silica nanoparticles could be homogeneously hybridized with aeryl resin without phase separation. The successfully fabricated hybrid materials exhibit efficient photocurability and simple film formation due to the photopolymerization of the organically modified colloidal-silica nanoparticles and acryl resin upon UV exposure. The fabricated hybrid films exhibit an excellent optical transmission of above 90% in the visible region as well as an enhanced surface smoothness of around 1 nm RMS roughness. In addition, the hybrid films exhibit improved thermal and mechanical characteristics, much better than those of acryl resin. More importantly, these photocurable hybrid materials fabricated through the synergistic combination of colloidal-silica nanoparticles with acryl resin are candidates for optical and electrical applications.

• Biomolecules & Therapeutics
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• 제12권4호
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• pp.250-256
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• 2004

Cordyceps possesses numerous health-promoting ingredients including hypoglycemic agents. The mechanism for the reduction of circulatory sugar content, however, is still not fully understand. In this study, 4-beta acetoxyscirpendiol (ASD) was purified from the methanolic extracts from fruiting bodies of Paecilomyces tenuipes. Na+/Glucose transporter-1 (SGLT-1) was expressed in the Xenopus oocytes. The effect of ASD on the oocyte expressed SGLT-1 was analyzed utilizing the voltage clamp and 2-deoxy-D-glucose (2-DOG) uptake studies. ASD was shown to significantly inhibit SGLT-1 activity compared to the non-treated control in a dose- dependent manner. In the presense of its two derivatives (diacetoxyscirpenol or 15-acetoxyscirpendiol), SGLT-1 activity was greatly inhibited similarly as ASD. Between ASD derivatives, 15-acetoxyscirepenol showed inhibition equivalent to that of ASD while diacetoxyscirpenol did less degree of inhibition. Insummary , these results strongly indicate that ASD in P. tenuipes may serve as a functional substance in lowering blood sugar in the circulatory system. ASD and its derivatives can be utilized as inhibitors of SGLT-1.

• Carbon letters
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• 제14권1호
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• pp.14-21
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• 2013

Physically and chemically activated carbons (ACs) exhibited high adsorption capacities for organic and inorganic pollutants compared with other adsorbents due to their expanded surface areas and wide pore volume distribution. In this work, seven steam-ACs with different burn-off have been prepared from cotton stalks. The textural properties of these sorbents were determined using nitrogen adsorption at $-196^{\circ}C$. The chemistry of the surface of the present sorbents was characterized by determining the surface functional C-O groups using Fourier transform infrared spectroscopy, surface pH, $pH_{pzc}$, and Boehm's acid-base neutralization method. The textural properties and the morphology of the sorbent surface depend on the percentage of burn-off. The surface acidity and surface basicity are related to the burn-off percentage. A theoretical model was developed to find a mathematical expression that relates the % burn-off to ash content, surface area, and mean pore radius. Also, the chemistry of the carbon surface is related to the % burn-off. A mathematical expression was proposed where % burn-off was taken as an independent factor and the other variable as a dependent factor. This expression allows the choice of the value of % burn-off with required steam-AC properties.

• BMB Reports
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• 제33권5호
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• pp.391-395
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• 2000

Calexcitin, a calcium-binding protein, was previously cloned and functionally characterized in the squid Loligo pealei. We now report the cloning of a second form of Calexcitin, Calexcitin-2, found in the squid Todarodes pacificus optic lobe. Calexcitin-2 has a significantly different carboxyl terminal region than Calexcitin-1. It lacks the CAAX motif, which is a farnesylation site. The amino acid sequence of Calexcitin-2 shows an 84% identity with Calexcitin-1 and also displays a strong cross immunoreactivity. Western blotting shows that Calexcitin-2 was expressed exclusively in the optic lobe region of squid, but not in other body organs. Regardless of its lack of conserved regions for GTP-binding, Calexcitin-2 shows moderately low affinity GTP-binding and also shows dramatic conformational change induced by GTP-binding. Three possible GTP-binding region mutations, K142A, D144A, and K157A, did not change the G TP binding affinity. This raises the possibility that Calexcitin-2 may have a novel GTP-binding motif.

• BMB Reports
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• 제42권12호
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• pp.788-793
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• 2009

TLX2 is an orphan homeodomain transcription factor whose expression is mainly associated with tissues derived from neural crest cells. Recently, we have demonstrated that PHOX2A and PHOX2B are able to enhance the neural cell-type specific expression of human TLX2 by binding distally the 5' -flanking region. In the present work, to deepen into the TLX2 transcription regulation, we have focused on the proximal 5'-flanking region of the gene, mapping the transcription start site and identifying a minimal promoter necessary and sufficient for the basal transcription in cell lines from different origin. Site-directed mutagenesis has allowed to demonstrate that the integrity of this sequence is crucial for gene expression, while electrophoretic mobility shift assays and chromatin immunoprecipitation experiments have revealed that such an activity is dependent on the binding of a PBX factor. Consistent with these findings, such a basal promoter activity has resulted to be enhanced by the previously reported PHOX2-responding sequence.

• BMB Reports
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• 제43권8호
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• pp.541-546
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• 2010

We utilized a mammalian expression system to purify and characterize autotaxin (ATX)/lysophospholipase D, an enzyme present in the blood responsible for biosynthesis of lysophosphatidic acid. The human ATX cDNA encoding amino acids 29-915 was cloned downstream of a secretion signal of CD5. At the carboxyl terminus was a thrombin cleavage site followed by the constant domain (Fc) of IgG to facilitate protein purification. The ATX-Fc fusion protein was expressed in HEK293 cells and isolated from conditioned medium of a stable clone by affinity chromatography with Protein A sepharose followed by cleavage with thrombin. The untagged ATX protein was further purified to essential homogeneity by gel filtration chromatography with a yield of approximately 5 mg/liter medium. The purified ATX protein was enzymatically active and biologically functional, offering a useful tool for further biological and structural studies of this important enzyme.

• The Plant Pathology Journal
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• 제25권1호
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• pp.47-53
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• 2009

Sequence analysis of the Chlorella virus SS-2 revealed one putative nuclease gene that is 807 bp long and encodes a 31kDa protein. Multiple sequence alignment analysis reveals the presence of highly conserved PD-(D/E)XK residues in the encoded protein. The gene cloned into an expression vector was expressed as a His-tagged fusion protein in chaperone containing pKJE7 cells. The recombinant protein was purified using a His-Trap chelating HP column and used for functional analysis. Exonuclease activity of the SS-2 nuclease was detected when the DNA substrates, such as linear ssDNA, PCR amplicon, linear dsDNA with 5'-overhang ends, 3'-overhang ends, or blunt ends were used. Covalently closed circular DNA was also degraded by the SS-2 recombinant protein, suggesting that the SS-2 nuclease has an endonuclease activity. Stable activity of SS-2 nuclease was observed between $10^{\circ}C$ and $50^{\circ}C$. The optimum pH concentrations for the SS-2 nuclease were pH 6.0-8.5. Divalent ions inhibited the SS-2 nuclease activity.