• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.5
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• pp.451-461
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• 2005

The effect of carbon dioxide on yeast growth was investigated during the cultivation of pH 5.0 and pH 6.8. by replacing the nitrogen part with carbon dioxide under aerobic conditions. The values of the specific growth rate under pH 5.0 and pH 6.8 conditions became 64.0% and 46.9%, respectively, compared to those before the change in gas composition. This suggests that the effect of carton dioxide was greater pronounced in pH 6.8 than in pH 5.0. The genome-wide transcriptional response to elevated carbon dioxide was examined using a DNA microarray. As for upregulated genes, it was noteworthy that 3 genes were induced upon entry into a stationary phase and 6 genes were involved in stress response. Of 53 downregulated genes, 22 genes were involved in the ribosomal biogenesis and assembly and 5 genes were involved in the lipid metabolism. These facts suggest that carbon dioxide could bring the cell conditions partially to a stationary phase. The ALD6 gene encoding for cytosolic acetaldehyde dehydrogenase was downregulated, which would lead to a lack of cell components for the growth. The downregulation of ALD6 was greater in pH 6.8 than in pH 5.0. consistent with physiological response. This suggests that it might be the most effective factor for growth inhibition.

• Molecules and Cells
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• v.19 no.2
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• pp.239-245
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• 2005

Factor for inversion stimulation (FIS), the Escherichia coli protein, is a positive regulator of the transcription of genes that encode stable RNA species, such as rRNA and tRNA. Transcription of the rnpB gene encoding M1 RNA, the catalytic subunit of E. coli RNase P, rapidly declines under stringent conditions, as does that of other stable RNAs. There are multiple putative FIS binding sites upstream of the rnpB promoter. We tested whether FIS binds to these sites, and if so, how it affects rnpB transcription. In vitro binding assays revealed specific binding of FIS to multiple sites in the rnpB promoter region. Interestingly, FIS bound not only to the upstream region of the promoter, but also to the region from +4 to +18. FIS activated rnpB transcription in vitro, but the level of activation was much lower than that of the rrnB promoter for rRNA. We also examined the effects of FIS on rnpB transcription in vivo using isogenic $fis^+$ and $fis^-$ strains. rnpB transcription was higher in the $fis^-$ than the $fis^+$ cells during the transitions from lag to exponential phase, and from exponential to stationary phase.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1077-1086
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• 2001

The sprA and sprB gene encoding chymotrypsin-like proteases Streptomyces griseus protease A (SGPA) and Streptomyces griseus protease B (SGPB) and the sprT gene that encodes Streptomyces griseus trypsin (SGT) were cloned from Streptomyces griseus ATCC10137 and overexpressed in Streptomyces lividans TK24 as a heterologous host. The chymotrypsin activity of tole culture broth measured with the artificial chromogenic substrate , N-succinyl-ala-ala-pro-phe-p-nitroanilide, was 10, 14 and 14 units/mg in the transformants haboring the sprA, sprB and sprD genes, respectively. The growth of S. lividans reached the maximum cell mass after 4 days of culture, yet SGPA and SGPD production started in the stationary phase of cell growth and kept increasing for up to 10 days of culture in an R2YE medium. The trypsin activity of the culture broth measured with the artificial chromogenic substrate , N-${\alpha}$-benzoyl-DL- arginine-p-nitroanilide , was 16 units/mg and SGT production started in the stationary phase of cell growth and kept increasing for up to 10 days of culture in an R2YE medium. The introduction of the sprA gene into S, lividans TK24 triggered the biosynthesis of pigmented antibiotics, actinorhodin and undecylprodigiosin, and induced significant morphological changes in the colonies in Benedict, R2YE, and R1R2 media. In addition, the introduction of the sprT gene also induced morphological changes in the colony shape without affecting the antibiotic production, thereby implying that certain proteases would appear to play very important and specific roles in secondary-metabolites formation and morphological differentiation in Streptomyces.

• The Journal of the Korea Contents Association
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• v.11 no.10
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• pp.30-40
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• 2011

Recently, together with the development of wireless communication technologies and the wide use of smart phones, the demand of the next generation mobile communication has been increased. To construct the next generation mobile communication platform efficiently for a short period from protocol development phase to protocol stability phase, an protocol analyzer is required to verify and analyze the protocol. In this paper, we propose the protocol analyzer of LTE network which is the leader of the next generation mobile communication platforms. The protocol analyzer is a software based agent-server architecture and uses XML metadata which defines intercommunication messages to analyze the protocol of the next generation mobile communications. We can analysis the encoding messages applied to LTE network using the loading of the decoding library. We verify the superiority of the proposed analyzer through an integrated test with LTE network.

• Journal of Korea Multimedia Society
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• v.15 no.7
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• pp.859-869
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• 2012

The Multi-view Video Coding (MVC) which is exploiting disparities between views has been developed to improve the coding efficiency of multi-view video. But MVC has a problem of having high computing complexities because of disparity estimation. This paper propose a fast mode decision for non-anchor picture to reduce the computational time of MVC. The proposed method uses two phases. Anchor pictures in hierarchical B picture structure have a higher correlation with prediction mode selection of non-anchor pictures, so in the first phase, prediction mode of non-anchor pictures is selected by exploiting the macro-block regions in anchor picture. In the second phase, we select a reference direction of inter prediction mode exploiting a higher correlation among reference directions of inter prediction modes of 7 block sizes. Experimental results show that the proposed method could save average about 44% in the encoding time with negligible coding efficiency losses.

• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.318-324
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• 2006

In order to develop an oral vaccine to prevent H. pylori infection, we have expressed the hpaA gene of H. pylori K51 isolated from Korean patients, encoding 29-kDa HpaA that is known to be localized on the cell surface and flagella sheath, in a live delivery vector system, Lactococcus lactis. The hpaA gene, amplified by PCR using the genomic DNA of H. pylori K51, was cloned in the pGEX-2T vector, and the DNA sequence analysis revealed that the hpaA gene of H. pylori K51 had 99.7% and 94.8% identity with individual hpaA genes of the H. pylori 26695 strain (U.K) and the J99 strain (U.S.A). A polyclonal anti-HpaA antibody was raised in rats using GST-HpaA fusion protein as the antigen. The hpaA gene was inserted in an E. coli-L. lactis-shuttle vector (pMG36e) to express in L. lactis. Western blot analysis showed that the expression level of HpaA in the L. lactis transformant remained constant from the exponential phase to the stationary phase, without extracelluar secretion. These results indicate that the HpaA of H. pylori K51 was successfully expressed in L. lactis, and suggest that the recombinant L. lactis expressing HpaA may be applicable as an oral vaccine to induce a protective immune response against H. pylori.

• Parasites, Hosts and Diseases
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• v.53 no.4
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• pp.431-438
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• 2015

In Trichinella spiralis infection, type 2 helper T (Th2) cell-related and regulatory T ($T_{reg}$) cell-related immune responses are the most important immune events. In order to clarify which Toll-like receptors (TLRs) are closely associated with these responses, we analyzed the expression of mouse TLR genes in the small intestine and muscle tissue during T. spiralis infection. In addition, the expression of several chemokine- and cytokine-encoding genes, which are related to Th2 and $T_{reg}$ cell mediated immune responses, were analyzed in mouse embryonic fibroblasts (MEFs) isolated from myeloid differentiation factor 88 (MyD88)/TIR-associated proteins (TIRAP) and Toll receptor-associated activator of interferons (TRIF) adapter protein deficient and wild type (WT) mice. The results showed significantly increased TLR4 and TLR9 gene expression in the small intestine after 2 weeks of T. spiralis infection. In the muscle, TLR1, TLR2, TLR5, and TLR9 gene expression significantly increased after 4 weeks of infection. Only the expression of the TLR4 and TLR9 genes was significantly elevated in WT MEF cells after treatment with excretory-secretory (ES) proteins. Gene expression for Th2 chemokine genes were highly enhanced by ES proteins in WT MEF cells, while this elevation was slightly reduced in MyD88/$TIRAP^{-/-}$ MEF cells, and quite substantially decreased in $TRIF^{-/-}$ MEF cells. In contrast, IL-10 and $TGF-{\beta}$ expression levels were not elevated in MyD88/$TIRAP^{-/-}$ MEF cells. In conclusion, we suggest that TLR4 and TLR9 might be closely linked to Th2 cell and $T_{reg}$ cell mediated immune responses, although additional data are needed to convincingly prove this observation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1073-1080
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• 2011

In this paper, we propose a novel digital watermarking method by virtual optics which secures multimedia information such as images, videos and sounds. To secure the multimedia data, we use Fresnel transform which describes the diffraction phenomena of the waves. Also, this method attaches the random phase function to Fresnel transform so that original image and watermark image would be gaussian random vectors. The complex numbers of watermark by Fresnel transform are separated the real part and the imaginary part. The former is embedded in original image as a encoding key imperceptibly and the latter is used for detecting the watermark as a decoding key. This method for digital watermarking ensures that watermark can be successfully registered and extracted from the watermarked image. Further, it provides the robustness to signal processing operation and geometric distortion and proves the strong resilience against cropping attack. The performance evaluation of the experiment is carried out with PSNR, and the numerical simulation results show the efficiency of the proposed method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.519-524
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• 2006

This paper describes an application of information presentation based geographic map for maritime information, including navigation information. The work is motivated by the need to prepare maritime information representation and distribution for future generation Web network technology. This works consist of map generation using GML and application to maritime information. GML 3.0 became an adopted specification of the Open Geospatial Consortium(OGC) in January 2003, and is rapidly emerging as the world standard for the encoding, transport and storage of all forms of geographic information. This paper looks at the application of GML to one of the more challenging areas of maritime information. Specific features of GML of interest to maritime information provider are discussed and then illustrated through a series of maritime information case studies. The first phase of the work consists of the construction of GML application schema for using as a base map of maritime information. Maritime information is acquired from multiple sources, including standards documents, database schemas, lexicons, collections of symbol definition. The sources of GML ontological knowledge and the contribution of each source to the overall ontology are described in this paper. In the second phase, the prepared GML is used to create a prototype of the mixed maritime information as a base map - for tagging documents within the maritime domain. An overview of this prototype is included. One application area for these information elements described here is the integrated retrieval of maritime information from diverse sources, ranging from Web sites to nautical chart databases and text documents.

• Investigative Magnetic Resonance Imaging
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• v.5 no.1
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• pp.38-42
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• 2001

Dark band artifacts are often observed in angiograms of arteries obtained by 2D time-of-flight (TOF) angiography with saturation of veins by presaturation RF pulses. At some arteries the arterial blood velocity varies in a triphasic pattern during a cardiac cycle. The arterial blood, that is saturated by presaturation RF pulses in the saturation band, can flow back into the imaging slice during the retrograde flow phase of the triphasic variation. When such saturated retrograde flow occurs during the acquisition of the central part of the K space, a signal void can result in base images and consequently dark band artifacts can appear in angiograms. This phenomenon is experimentally demonstrated by varying the gap between the imaging slice and the saturation band. Furthermore, a new pulse sequence is proposed to eliminate the dark band artifacts by changing the profile of the saturation band front a rectangle to a ramp.