• 한국정보통신학회논문지
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• 제10권12호
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• pp.2230-2234
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• 2006

SCORM에서 SCO는. 학습자가 검색하는 학습 단위가 된다. e-러닝 환경에서 학습자가 찾는 SCO를 신속하게 검색할 수 있는 저장 방법이 필요하다. 본 논문에서는 SCO의 클러스터링 방법을 수학적으로 정형화하여 정의하였다. 또한 SCO를 평가하는 기준을 제시하였고 각 SCO를 평가하는 절차를 나타내었다. 실험을 통하여 제안한 클러스터링 방법에 기반을 둔 검색이 기존의 검색 방법보다 성능이 우수함을 보였다.

• 정보보호학회논문지
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• 제18권4호
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• pp.27-35
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• 2008

본 논문에서는 블록 암호 SCO-1[12]에 대한 연관키 차분 공격을 소개한다. 본 논문에서 소개하는 공격은 SCO-1에 대한 첫 번째 공격이며 $2^{61}$개의 연관키 선택 암호문을 이용하여 $2^{120.59}$의 SCO-1 복호화 연산을 수행하여 SCO-1의 128-비트 비밀키를 복구한다.

• Journal of Microbiology and Biotechnology
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• 제31권11호
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• pp.1591-1600
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• 2021

Streptomyces coelicolor is a filamentous soil bacterium producing several kinds of antibiotics. S. coelicolor abs8752 is an abs (antibiotic synthesis deficient)-type mutation at the absR locus; it is characterized by an incapacity to produce any of the four antibiotics synthesized by its parental strain J1501. A chromosomal DNA fragment from S. coelicolor J1501, capable of complementing the abs- phenotype of the abs8752 mutant, was cloned and analyzed. DNA sequencing revealed that two complete ORFs (SCO6992 and SCO6993) were present in opposite directions in the clone. Introduction of SCO6992 in the mutant strain resulted in a remarkable increase in the production of two pigmented antibiotics, actinorhodin and undecylprodigiosin, in S. coelicolor J1501 and abs8752. However, introduction of SCO6993 did not show any significant difference compared to the control, suggesting that SCO6992 is primarily involved in stimulating the biosynthesis of antibiotics in S. coelicolor. In silico analysis of SCO6992 (359 aa, 39.5 kDa) revealed that sequences homologous to SCO6992 were all annotated as hypothetical proteins. Although a metalloprotease domain with a conserved metal-binding motif was found in SCO6992, the recombinant rSCO6992 did not show any protease activity. Instead, it showed very strong β-glucuronidase activity in an API ZYM assay and toward two artificial substrates, p-nitrophenyl-β-D-glucuronide and AS-BI-β-D-glucuronide. The binding between rSCO6992 and Zn²⁺ was confirmed by circular dichroism spectroscopy. We report for the first time that SCO6992 is a novel protein with β-glucuronidase activity, that has a distinct primary structure and physiological role from those of previously reported β-glucuronidases.

• Journal of Applied Biological Chemistry
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• 제56권3호
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• pp.165-170
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• 2013

The SCO3388 gene from Streptomyces coelicolor is homologous to tmrB, the tunicamycin resistance gene of Bacillus subtilis. The SCO3388-inactivation strain (SY-tbl-1) was generated by replacing SCO3388 with thiostrepton resistance gene. Spores of S. coelicolor derivatives were prepared on mannitol-soy flour (MS) agar on which SY-tbl-1 displayed no significant defect in growth and development. When plated on R4 agar, spores of SYtbl-1 displayed retardation in growth and sporulation, whereas its mycelium gave rise to normal growth. Thus, SCO3388 is suggested to be involved in the dormant spore germination. Expression of SCO3388 under the ermE1 promoter restored but only partially the ability to sporulate in SY-tbl-1. Neither SY-tbl-1 nor SY-tbl-1/ermE1p-SCO3388 showed a difference in tunicamycin resistance to the wild type whereas, interestingly, the introduction of ermE1p-SCO3388 dramatically enhanced spore survival to heat and detergent treatments, suggesting that SCO3388 might play a role in the maintenance of spore cell wall integrity.

• 정보처리학회논문지A
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• 제9A권4호
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• pp.615-620
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• 2002

SCORM은 교육용 컨텐츠를 SCO라는 객체 단위로 공유하고 재사용하기 위한 국제적 표준이다. 그러나 유사 영역에서의 학습 컨텐츠 재사용시 컨텐츠의 일부분을 변경해야 할 경우에도 컨텐츠 원본을 수정해야 하는 문제점을 안고 있다. 따라서 이 논문에서는 이러한 문제점을 해결하기 위해 상속이 가능한 컨텐츠를 개발할 수 있는 I-SCO 모델을 제안한다. I-SCO 모델은 SCORM 기반 컨텐츠의 오버로딩과 오버라이딩을 통한 상속을 지원하여 컨텐츠의 재사용성을 증대시킨다. 실험에서는 제안한 I-SCO 모델을 설계 및 구현하여 ADL에서 배포하는 실행환경에서 실행시켜 봄으로써 컨텐츠의 상속 기능을 확인하고 I-SCO 모델의 타당성을 입증한다.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 1999년도 Japanese Journal of Medical Physics
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• pp.392-396
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• 1999

• Journal of Microbiology and Biotechnology
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• 제17권11호
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• pp.1818-1825
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• 2007

S-Adenosylmethionine (SAM) was previously documented to activate secondary metabolism in a variety of Streptomyces spp. and to promote actinorhodin (ACT) and undecylprodigiosin (RED) in Streptomyces coelicolor. The SAM-induced proteins in S. coelicolor include several ABC transporter components (SCO5260 and SCO5477) including BldKB, the component of a well-known regulatory factor for differentiations. In order to assess the role of these ABC transporter complexes in differentiation of Streptomyces, SCO5260 and SCO5476, the first genes from the cognate complex clusters, were individually inactivated by gene replacement. Inactivation of either SCO5260 or SCO5476 led to impaired sporulation on agar medium, with the more drastic defect in the SCO5260 null mutant (${\Delta}SCO5260$). ${\Delta}SCO5260$ displayed growth retardation and reduced yields of ACT and RED in liquid cultures. In addition, SAM supplementation failed in promoting the production of ACT and RED in ${\Delta}SCO5260$. Inactivation of SCO5476 gave no significant change in growth and production of ACT and RED, but impaired the promoting effect of SAM on ACT production without interfering with the effect on RED production. The present study suggests that SAM induces several ABC transporters to modulate secondary metabolism and morphological development in S. coelicolor.

• Journal of Microbiology and Biotechnology
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• 제31권5호
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• pp.756-763
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• 2021

Agarose is a linear polysaccharide composed of ᴅ-galactose and 3,6-anhydro-ʟ-galactose (AHG). It is a major component of the red algal cell wall and is gaining attention as an abundant marine biomass. However, the inability to ferment AHG is considered an obstacle in the large-scale use of agarose and could be addressed by understanding AHG catabolism in agarolytic microorganisms. Since AHG catabolism was uniquely confirmed in Vibrio sp. EJY3, a gram-negative marine bacterial species, we investigated AHG metabolism in Streptomyces coelicolor A3(2), an agarolytic gram-positive soil bacterium. Based on genomic data, the SCO3486 protein (492 amino acids) and the SCO3480 protein (361 amino acids) of S. coelicolor A3(2) showed identity with H2IFE7.1 (40% identity) encoding AHG dehydrogenase and H2IFX0.1 (42% identity) encoding 3,6-anhydro-ʟ-galactonate cycloisomerase, respectively, which are involved in the initial catabolism of AHG in Vibrio sp. EJY3. Thin layer chromatography and mass spectrometry of the bioconversion products catalyzed by recombinant SCO3486 and SCO3480 proteins, revealed that SCO3486 is an AHG dehydrogenase that oxidizes AHG to 3,6-anhydro-ʟ-galactonate, and SCO3480 is a 3,6-anhydro-ʟ-galactonate cycloisomerase that converts 3,6-anhydro-ʟ-galactonate to 2-keto-3-deoxygalactonate. SCO3486 showed maximum activity at pH 6.0 at 50℃, increased activity in the presence of iron ions, and activity against various aldehyde substrates, which is quite distinct from AHG-specific H2IFE7.1 in Vibrio sp. EJY3. Therefore, the catabolic pathway of AHG seems to be similar in most agar-degrading microorganisms, but the enzymes involved appear to be very diverse.

• Journal of Microbiology and Biotechnology
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• 제32권9호
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• pp.1134-1145
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• 2022

SCO6993 (606 amino acids) in Streptomyces coelicolor belongs to the large ATP-binding regulators of the LuxR family regulators having one DNA-binding motif. Our previous findings predicted that SCO6993 may suppress the production of pigmented antibiotics, actinorhodin, and undecylprodigiosin, in S. coelicolor, resulting in the characterization of its properties at the molecular level. SCO6993-disruptant, S. coelicolor ΔSCO6993 produced excess pigments in R2YE plates as early as the third day of culture and showed 9.0-fold and 1.8-fold increased production of actinorhodin and undecylprodigiosin in R2YE broth, respectively, compared with that by the wild strain and S. coelicolor ΔSCO6993/SCO6993⁺. Real-time polymerase chain reaction analysis showed that the transcription of actA and actII-ORF4 in the actinorhodin biosynthetic gene cluster and that of redD and redQ in the undecylprodigiosin biosynthetic gene cluster were significantly increased by SCO6993-disruptant. Electrophoretic mobility shift assay and DNase footprinting analysis confirmed that SCO6993 protein could bind only to the promoters of pathway-specific transcriptional activator genes, actII-ORF4 and redD, and a specific palindromic sequence is essential for SCO6993 binding. Moreover, SCO6993 bound to two palindromic sequences on its promoter region. These results indicate that SCO6993 suppresses the expression of other biosynthetic genes in the cluster by repressing the transcription of actII-ORF4 and redD and consequently negatively regulating antibiotic production.

• Journal of Microbiology and Biotechnology
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• 제20권3호
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• pp.480-484
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• 2010

AfsR2 is a global regulatory protein that stimulates antibiotic biosynthesis in both Streptomyces lividans and S. coelicolor. Previously, various afsR2-dependent genes including a putative abaA-like regulatory gene, SCO4677, were identified through comparative DNA microarray analysis. To further identify the putative SCO4677-dependent proteins, the comparative proteomics-driven approach was applied to the SCO4677-overexpressing strains of S. lividans and S. coelicolor along with the wild-type strains. The 2D gel electrophoresis gave approximately 277 protein spots for S. lividans and 207 protein spots for S. coelicolor, showing different protein expression patterns between the SCO4677-overexpressing strains and the wild-type strains. Further MALDI-TOF analysis revealed that only 18 proteins exhibited similar expression patterns in both S. lividans and S. coelicolor, suggesting that the SCO4677 could encode an abaA-like regulator that controls a few cross-species common proteins as well as many species-specific proteins in Streptomyces species.