• Journal of Forest and Environmental Science
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• 제40권2호
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• pp.118-122
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• 2024

This study reported the novel use of fallen leaf extract as a microbial culture media for the first time. Extract from hardwood fallen leaves (HLE) was prepared under high temperature and pressure conditions and then supplemented with specific nutrients. The growth of four industrially significant prokaryotes on the HLE-based media was measured and compared with that on enriched media (Luria-Bertani, LB). Notably, supplementing HLE with only 0.5 g of yeast extract and 1 g tryptone per liter showed a similar growth rate of Pseudomonas chlororaphis compared to standard LB media. Overall, the HLE media developed in this study offers a sustainable and cost-effective approach to microbial media production, capitalizing on the valorization of forest waste.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2001년도 Proceedings of 2001 International Symposium
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• pp.83-89
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• 2001

Recent advances in the structural and molecular biology uncovered that a set of translation factors resembles a tRNA shape and, in one case, even mimics a tRNA function for deciphering the genetic ：ode. Nature must have evolved this 'art' of molecular mimicry between protein and ribonucleic acid using different protein architectures to fulfill the requirement of a ribosome 'machine'. Termination of protein synthesis takes place on the ribosomes as a response to a stop, rather than a sense, codon in the 'decoding' site (A site). Translation termination requires two classes of polypeptide release factors (RFs)： a class-I factor, codon-specific RFs (RFI and RF2 in prokaryotes; eRFI in eukaryotes), and a class-IT factor, non-specific RFs (RF3 in prokaryotes; eRF3 in eukaryotes) that bind guanine nucleotides and stimulate class-I RF activity. The underlying mechanism for translation termination represents a long-standing coding problem of considerable interest since it entails protein-RNA recognition instead of the well-understood codon-anticodon pairing during the mRNA-tRNA interaction. Molecular mimicry between protein and nucleic acid is a novel concept in biology, proposed in 1995 from three crystallographic discoveries, one, on protein-RNA mimicry, and the other two, on protein-DNA mimicry. Nyborg, Clark and colleagues have first described this concept when they solved the crystal structure of elongation factor EF- Tu：GTP：aminoacyl-tRNA ternary complex and found its overall structural similarity with another elongation factor EF-G including the resemblance of part of EF-G to the anticodon stem of tRNA (Nissen et al. 1995). Protein mimicry of DNA has been shown in the crystal structure of the uracil-DNA glycosylase-uracil glycosylase inhibitor protein complex (Mol et al. 1995; Savva and Pear 1995) as well as in the NMR structure of transcription factor TBP-TA $F_{II}$ 230 complex (Liu et al. 1998). Consistent with this discovery, functional mimicry of a major autoantigenic epitope of the human insulin receptor by RNA has been suggested (Doudna et al. 1995) but its nature of mimic is. still largely unknown. The milestone of functional mimicry between protein and nucleic acid has been achieved by the discovery of 'peptide anticodon' that deciphers stop codons in mRNA (Ito et al. 2000). It is surprising that it took 4 decades since the discovery of the genetic code to figure out the basic mechanisms behind the deciphering of its 64 codons.

• 생명과학회지
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• 제29권1호
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• pp.123-128
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• 2019

원핵생물 분류의 기본단위인 종(species)의 동정에 16S rDNA가 사용되지만 한계가 있고 원핵생물의 속(genus)에 대한 연구가 많지 않다. 본 연구에서는 보존 유전자를 확보한 COG database와 대사경로를 확보한 MetaCyc database에 공통적인 원핵생물 중 속이 같고 종이 다른 13개 속 28개의 원핵생물을 대상으로 속 수준에서 연구하였다. 전체 유전자에서 core-genome인 속 보존 유전자의 비율은 최저 27.62%(Nostoc 속)에서 71.76%(Spiribacter 속)의 범위로 평균 46.72%였다. 각 원핵생물에서 core-genome의 비율이 낮으면 특이한 생명현상을 보이거나 서식지가 다양할 수 있을 것이다. 속 수준의 공통 대사경로의 비율은 최저 58.79%(Clostridium 속)에서 최대 96.31%(Mycoplasma 속), 평균 75.86%로 core-genome의 비율보다 높았다. 비교대상을 확장하면 속 특이 보존 유전자와 대사경로는 확인할 수 없었다. 보존 유전자와 대사경로 보유 계통수에서는 대체로 같은 속의 구성원들이 가장 인접하였으며, Bacillus속과 Clostridium 속이 그룹을 형성하였고, 고세균끼리 그룹을 형성하였다. 보존 유전자 보유계통수에서는 Acidobacteria, Cyanobacteria, Proteobacteria 문(phylum)의 Granulicella, Nostoc, Bradyrhizobium의 3개 속이 하나의 그룹을 형성하였다. 본 연구 결과는 (i) 각 계통 단계에서 보존유전자와 대사경로의 확인, (ii) 수평적 유전자 전달 또는 부위 지정 돌연변이를 통한 균주의 개선 등의 분야에 기초자료로 활용될 수 있을 것이다.

• 유기물자원화
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• 제18권3호
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• pp.31-37
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• 2010

Chitinase (EC 3.2.1.14)는 곰팡이와 곤충 등에서 세포벽이나 외골격을 형성하는 생물학적 방어기질의 구성 요소인 chitin의 ${\beta}$-1,4-linkages를 가수분해하는 효소이다. 이러한 chitinase를 포함하는 Glycosyl hydrolases 18 family는 Archea, Prokaryotes 그리고 Eukaryotes에 널리 퍼져 있는 Ancient gene으로 알려져 있다. 그 중, 지렁이는 곰팡이와 세균이 많은 환경에서 자라기 때문에 이러한 미생물들의 공격으로부터 스스로를 보호할 수 있는 면역체계를 가지고 있는 것으로 알려져 왔다. 본 연구에서는, 붉은줄지렁이 (Eisenia andrei)의 중장에서 발현되는 Chitinases의 cDNA 서열을 얻기 위해 기존에 알려져 있던 EST 서열을 가지고 RT-PCR 및 RACE-PCR을 수행하였고 이를 통해 E. andrei의 중장에서 발현되는 Chitinase의 특성을 동정 및 규명하였다. 그 결과 309개의 아미노산을 암호화하는 927개의 염기 서열을 얻을 수 있었으며 다른 종들의 Chitinases와 아미노산 서열을 비교 분석한 결과 지렁이의 Chitinase는 Glycosyl hydrolases 18 family에 속하고, 기질 결합과 촉매 작용에 관여하는 2개의 영역이 잘 보존되어 있는 것으로 나타났다.

• Genomics & Informatics
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• 제10권1호
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• pp.9-15
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• 2012

Horizontal gene transfer (HGT) is the movement of genetic material between kingdoms and is considered to play a positive role in adaptation. $Cryptosporidium$ $parvum$ is a parasitic protozoan that causes an infectious disease. Its genome sequencing reported 14 bacteria-like proteins in the nuclear genome. Among them, cgd2_1810, which has been annotated as CysQ, a sulfite synthesis pathway protein, is listed as one of the candidates of genes horizontally transferred from bacterial origin. In this report, we examined this issue using phylogenetic analysis. Our BLAST search showed that $C.$ $parvum$ CysQ protein had the highest similarity with that of proteobacteria. Analysis with NCBI's Conserved Domain Tree showed phylogenetic incongruence, in that $C.$ $parvum$ CysQ protein was located within a branch of proteobacteria in the cd01638 domain, a bacterial member of the inositol monophosphatase family. According to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, the sulfate assimilation pathway, where CysQ plays an important role, is well conserved in most eukaryotes as well as prokaryotes. However, the Apicomplexa, including $C.$ $parvum$, largely lack orthologous genes of the pathway, suggesting its loss in those protozoan lineages. Therefore, we conclude that $C.$ $parvum$ regained cysQ from proteobacteria by HGT, although its functional role is elusive.

• BMB Reports
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• 제32권3호
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• pp.215-225
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• 1999

Phytochromes (with gene family members phyA, B, C, D, and E) are a wavelength-dependent light sensor or switch for gene regulation that underscore a number of photo responsive developmental and morphogenic processes in plants. Recently, phytochrome-like pigment proteins have also been discovered in prokaryotes, possibly functioning as an auto-phosphorylating/phosphate-relaying two-component signaling system (Yeh et al., 1997). Phytochromes are photochromically convertible between the light sensing Pr and regulatory active Pfr forms. Red light converts Pr to Pfr, the latter having a "switch-on" conformation. The Pfr form triggers signal transduction pathways to the downstream responses including the expression of photosynthetic and other growth-regulating genes. The components involved in and the molecular mechanisms of the light signal transduction pathways are largely unknown, although G-proteins, protein kinases, and secondary messengers such as $Ca^{2+}$ ions and cGMP are implicated. The 124-127 kDa phytochromes form homodimeric structures. The N-terminal half contains the tetrapyrrolic phytochromobilin for red/far-red light absorption. The C-terminal half includes both a dimerization motif and regulatory box where the red light signal perceived by the chromophore-domain is recognized and transduced to initiate the signal transduction cascade. A working model for the inter-domain signal communication within the phytochrome molecule is proposed in this Review.

• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2005년도 BIOINFO 2005
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• pp.72-77
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• 2005

Orthologs are genes having the same function across different species that specialize from a single gene in the last common ancestor of these species. Orthologous groups are useful in the genome annotation, studies on gene evolution, and comparative genomics. However, the construction of an orthologous group is difficult to automate and it takes so much time. It is also hard to guarantee the accuracy of the constructed orthologous groups. We propose a system to construct orthologous groups on many genomes automatically and rapidly. We utilize the grid computing to reduce the sequence alignment time, and we use clustering algorithm in the application of database to automate whole processes. We have generated orthologous groups for 20 complete prokaryotes genomes just in a day because of the grid computing. Furthermore, new genomes can be accommodated easily by the clustering algorithm and grid computing. We compared the generated orthologous groups with COGs (Clusters of orthologous Group of proteins) and KO (KEGG Ortholog). The comparison shows about 85 percent similarity compared with previous well-known orthologous databases.

• Journal of Microbiology
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• 제40권4호
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• pp.319-326
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• 2002

Cellular DNA in prokaryotes is organized in nucleic acid-protein self-assemblies referred to as the nucleoid. The physical forces responsible for its stability inside the poor solvent properties of the cytoplasm and their functional implications are not understood. Studies on the organisation and functioning of the cytosol of cells largely rely on experimental protocols performed in highly dilute solutions using biochemically purified molecules, which is not a reliable substitute for the situation existing in vivo. Our current research interest is focused on the characterization of biological and physical forces determining the compaction and phase separation of DNA in Escherichia coli cytoplasm. We have emphasized the effect of excluded volume in solutions with high macromolecular concentrations (macromolecular crowding) upon self-association patterns of reactions. The prokaryotic cytosol was simulated by addition of inert polymer polyethylene glycol (PEG) (average molecular weight 20000), as an agent which afterwards facilitates the self-association of macromolecules. Fluorescence microscopy was used for direct visualization of nucleoids in intact cells, after staining with DAPI (4',6-diamidino-2-phenylindole dihydrochloride). Addition of the crowding agent PEG 20,000, in increasing concentrations generated progressively enhanced nucleoid compaction, the effect being stronger in the presence of 0.2 M NaCl and 5 mM MgCl$\_$2/. Under these conditions, the nucleoids were compacted to volumes of around 2 ㎛$\^$3/ or comparable sizes with that of living cells.

• Journal of Microbiology and Biotechnology
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• 제18권9호
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• pp.1529-1536
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• 2008

Acetylation of lysine residues in proteins is a reversible and highly regulated posttranslational modification. However, it has not been systematically studied in prokaryotes. By affinity immunoseparation using an anti-acetyllysine antibody together with nano-HPLC/MS/MS, we identified 125 lysine-acetylated sites in 85 proteins among proteins derived from Escherichia coli. The lysine-acetylated proteins identified are involved in diverse cellular functions including protein synthesis, carbohydrate metabolism, the TCA cycle, nucleotide and amino acid metabolism, chaperones, and transcription. Interestingly, we found a higher level of acetylation during the stationary phase than in the exponential phase; proteins acetylated during the stationary phase were immediately deacetylated when the cells were transferred to fresh LB culture medium. These results demonstrate that lysine acetylation is abundant in E. coli and might be involved in modifying or regulating the activities of various enzymes involved in critical metabolic processes and the synthesis of building blocks in response to environmental changes.

• 한국자기공명학회논문지
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• 제24권3호
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• pp.86-90
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• 2020

Iron-sulfur (Fe-S) clusters are one of the most ancient yet essential cofactors mediating various essential biological processes. In prokaryotes, Fe-S clusters are generated via several distinctive biogenesis mechanisms, among which the ISC (Iron-Sulfur Cluster) mechanism plays a house-keeping role to satisfy cellular needs for Fe-S clusters. The Escherichia coli ISC mechanism is maintained by several essential protein factors, whose structural characterization has been of great interest to reveal mechanistic details of the Fe-S cluster biogenesis mechanisms. In particular, nuclear magnetic resonance (NMR) spectroscopic approaches have contributed much to elucidate dynamic features not only in the structural states of the protein components but also in the interaction between them. The present minireview discusses recent advances in elucidating structural features of IscU, the key player in the E. coli ISC mechanism. IscU accommodates exceptional structural flexibility for its versatile activities, for which NMR spectroscopy was particularly successful. We expect that understanding to the structural diversity of IscU provides critical insight to appreciate functional versatility of the Fe-S cluster biogenesis mechanism.