• Journal of Microbiology
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• 제39권3호
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• pp.149-153
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• 2001

The electron transfer reaction is one of the most essential processes of life. Not only does it provide the means of transforming solar and chemical energy into a utilizable form for all living organisms, it also extends into a range of metabolic processes that support the life of a cell. Thus, it is of great interest to understand the physical basis of the rates and reduction potentials of these reactions. To identify the major determinants of reduction potentials in redox proteins, we have chosen the simplest electron transfer protein, rubredoxin, a small (52-54 residue) iron-sulfur protein family, widely distributed in bacteria and archaea. Rubredoxins can be grouped into two classes based on the correlation of their reduction potentials with the identity of residue 44; those with Ala44 (ex: Pyrococcus furiosus) have reduction potentials that are ∼50 mV higher than those with Va144 (ex: Clostridium pasteurianum). Based on the crystal structures of rubredoxins from C. pasteurianum and P. furiosus, we propose the identity of residue 44 alone determines the reduction potential by the orientation of the electric dipole moment of the peptide bond between 43 and 44. Based on 1.5 $\AA$ resolution crystal structures and molecular dynamics simulations of oxidized and reduced rubredoxins from C. pasteurianum, the structural rearrangements upon reduction suggest specific mechanisms by which electron transfer reactions of rubredoxin should be facilitated.

• 한국측량학회지
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• 제29권4호
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• pp.381-392
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• 2011

본 연구는 하천 유역에 대한 수문분석의 대표적인 요소인 유출량과 오염부하량을 추정하는데 있어서 기존의 수문학적 모델링 방법과는 달리 GIS분석기법을 적용하였다. 분석을 위한 기본 자료로는 토양도, 토지이용도, 수계도, 강수량 등의 유역형태 및 기상학적 특성을 정량화한 지리정보자료와 수치표고모형과 같은 지형 자료를 이용하였다. 토양, 토지 이용 인자에 대한 기준값으로는 미국토양보존국(SCS)에서 제시하고 있는 토양 분류 기준 및 유출곡선지수(CN)와 환경부에서 제시하고 있는 토양의 기대평균농도(EMC)를 적용하였다. 고흥군 고읍천 유역의 2010년 7월~8윌의 9개 강우사상에 대하여 유출량 및 오염부하량의 추정값과 실측값을 비교한 결과, 유출량은 평균 3.86%의 차이를 갖으며, 오염부하량은 평균 5.67%의 차이를 갖는 것으로 분석되었다. 그러나 각 강우사상별 분석결과 추정 유출량은 강우량이 적을수록 그 오차가 매우 커지며, 추정 오염부하량은 강우량 및 계절의 변화에 따라 오차량에 차이가 있는 것으로 분석되었다. 향후 우리나라의 토양 및 토지이용에 적합한 배수 분류기준과 지역별 특성을 고려한 기대평균농도가 제시된다면 보다 정확한 유출량 및 오염부하량의 추정이 가능할 것으로 판단된다.

• Journal of Microbiology and Biotechnology
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• 제33권11호
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• pp.1428-1436
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• 2023

The three Gram-negative, catalase- and oxidase-positive bacterial strains RS43^T, HBC28, and HBC61^T, were isolated from fresh water and subjected to a polyphasic study. Comparison of 16S rRNA gene sequence initially indicated that strains RS43^T, HBC28, and HBC61^T were closely related to species of genus Curvibacter and shared the highest sequence similarity of 98.14%, 98.21%, and 98.76%, respectively, with Curvibacter gracilis 7-1^T. Phylogenetic analysis based on genome sequences placed all strains within the genus Curvibacter. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the three strains and related type strains supported their recognition as two novel genospecies in the genus Curvibacter. Comparative genomic analysis revealed that the genus possessed an open pangenome. Based on KEGG BlastKOALA analyses, Curvibacter species have the potential to metabolize benzoate, phenylacetate, catechol, and salicylate, indicating their potential use in the elimination of these compounds from the water systems. The results of polyphasic characterization indicated that strain RS43^T and HBC61^T represent two novel species, for which the name Curvibacter microcysteis sp. nov. (type strain RS43^T =KCTC 92793^T=LMG 32714^T) and Curvibacter cyanobacteriorum sp. nov. (type strain HBC61^T =KCTC 92794^T=LMG 32713^T) are proposed.

• Journal of Microbiology and Biotechnology
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• 제20권8호
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• pp.1210-1214
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• 2010

Many bacteria are involved in the fermentation of doenjang, and Bacillus species are known to perform significant roles. Although SDS-PAGE has been frequently used to classify and identify bacteria in various samples, the microbial diversity in doenjang has not yet been investigated. This study aims to determine the identity and distribution of dominant Bacillus species in doenjang using SDS-PAGE profiles of whole-cell proteins and 16S rRNA gene sequencing. Reference Bacillus strains yielded differential SDS-PAGE banding patterns that could be considered to be highly specific fingerprints. Grouping of bacterial strains isolated from doenjang samples by whole-cell protein patterns was confirmed by analysis of their 16S rRNA gene sequences. B. subtilis was found to be the most dominant strain in most of the samples, whereas B. licheniformis and B. amyloliquefaciens were less frequently found but were also detected in several samples. The results obtained in this study show that a combined identification method using SDS-PAGE profiles of whole-cell proteins and subsequent 16S rRNA gene sequence analysis could successfully identify Bacillus species isolated from doenjang.

• Journal of Microbiology and Biotechnology
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• 제32권5호
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• pp.575-581
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• 2022

A Gram-stain-negative, white-coloured, and rod-shaped bacterium, strain DR4-4^T, was isolated from Daechung Reservoir, Republic of Korea, during Microcystis bloom. Strain DR4-4^T was most closely related to Caenimonas terrae SGM1-15^T and Caenimonas koreensis EMB320^T with 98.1% 16S rRNA gene sequence similarities. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain DR4-4^T and closely related type strains were below 79.46% and 22.30%, respectively. The genomic DNA G+C content was 67.5%. The major cellular fatty acids (≥10% of the total) were identified as C_16:0, cyclo C_17:0, summed feature 3 (C_16:1ω7c and/or C_16:1ω6c), and summed feature 8 (C_18:1ω7c and/or C_18:1ω6c). Strain DR4-4^T possessed phosphatidylethanolamine, diphosphatidylglycerol, and phosphatidylglycerol as the main polar lipids and Q-8 as the respiratory quinone. The polyamine profile was composed of putrescine, cadaverine, and spermidine. The results of polyphasic characterization indicated that the isolated strain DR4-4^T represents a novel species within the genus Caenimonas, for which the name Caenimonas aquaedulcis sp. nov. is proposed. The type strain is DR4-4^T (=KCTC 82470^T =JCM 34453^T).

• Journal of Microbiology and Biotechnology
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• 제32권12호
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• pp.1553-1560
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• 2022

A Gram-stain-negative, rod-shaped bacterial strain, JC4^T, was isolated from a freshwater sample and determined the taxonomic position. Initial identification based on 16S rRNA gene sequences revealed that strain JC4^T is affiliated to the genus Mucilaginibacter with a sequence similarity of 97.97% to Mucilaginibacter rigui WPCB133^T. The average nucleotide identity and digital DNA-DNA hybridization values between strain JC4^T and Mucilaginibacter species were estimated below 80.92% and 23.9%, respectively. Strain JC4^T contained summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c) and iso-C_15:0 as predominant cellular fatty acids. The dominant polar lipids were identified as phosphatidylethanolamine, one unidentified aminophospholipid, one unidentified phospholipid, and two unidentified lipids. The respiratory quinone was MK-7. The genomic DNA G+C content of strain JC4^T was determined to be 42.44%. The above polyphasic evidences support that strain JC4^T represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter aquariorum sp. nov. is proposed. The type strain is JC4^T (= KCTC 92230^T = LMG 32715^T).

• Journal of Microbiology and Biotechnology
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• 제13권1호
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• pp.119-124
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• 2003

This study was conducted to evaluate the practical usefulness of the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PACE) fingerprinting of whole cell proteins far the identification of lactic acid bacteria in Kimchi. SDS- PACE of whole cell proteins of the reference strains and lactic acid bacteria isolated from Kimchi yielded differential banding patterns that were highly specific fingerprints, thus making it possible to identify. Identification of the isolates from Kimchi was achieved by comparing the SDS-PAGE fingerprints of isolates to those of reference strains. In addition, the reliability of SDS-PAGE was examined by comparing the results with those of the APL 50 CHL system assay and 16S rRNA gene sequence. SDS-PACE assay showed a different identity to reference strains, while the APL 50 CHL system and 16S rRNA gene sequence could not distinguish a few strains. Therefore, SDS-PAGE of the whole cell proteins is a specific and a reliable method that will be useful for the identification of lactic acid bacteria in Kimchi to the species level, and can be used as an alternative or complementary identification method.

• 대한의생명과학회지
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• 제12권4호
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• pp.419-425
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• 2006

Phospholipase $C-{\gamma}1\;(PLC-{\gamma}1)$ is an important signaling molecule for cell proliferation and differentiation. $PLC-{\gamma}1$ contains two pleckstrin homology (PH) domains, which are responsible for protein-protein interaction and protein-lipid interaction. $PLC-{\gamma}1$ also has two Src homology (SH)2 domains and a SH3 domain, which are responsible for protein- protein interaction. To identity proteins that specifically binds to PH domain of $PLC-{\gamma}1$, we prepared and incubated the glutathione S-transferase(GST)-fused PH domains of $PLC-{\gamma}1$ with COS7 cell lysate. We found that 90 kDa protein specifically binds to PH domain of $PLC-{\gamma}1$. By matrix-assisted laser desorption ionization time of flight-mass spectrometry, the 90 kDa protein revealed to be heat shock protein (Hsp) $90{\beta}$. Hsp $90{\beta}$ is a molecular chaperone that stabilizes and facilitates the folding of proteins that are involved in cell signaling, including receptors for steroids hormones and a variety of protein kinases. To know whether Hsp $90{\beta}$ affects on $PLC-{\gamma}1$ activity, we performed $PIP_2$ hydrolyzing activity of $PLC-{\gamma}1$ in the presence of purified Hsp $90{\beta}$ in vitro. Our results show that the Hsp $90{\beta}$ dose-dependently inhibits the enzymatic activity of $PLC-{\gamma}1$ and further suggest that Hsp $90{\beta}$ regulates cell growth and differentiation via regulation of $PLC-{\gamma}1$ activity.

• 한국항행학회논문지
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• 제23권5호
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• pp.437-443
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• 2019

본 논문에서는 LTE 기지국 (BS; base station)과 단말기 (UE; user equipment) 간의 거리를 신호 도달 시간 (TOA; time-of-arrival)을 이용해 계산하는 알고리즘을 소개하였다. 먼저, 수신된 신호를 발신한 기지국을 판별하기 위해 primary synchronization signal (PSS)와 secondary synchronization signal (SSS)를 이용하여 셀 아이디를 취득하였다. 제시된 알고리즘에서는 상용 LTE 신호에 포함된 기준 시퀀스인 cell-specific reference signal (CRS)를 구축된 자원 그리드에서의 2차원 상호 상관을 통해 지연 시간을 계산하였다. 지연 시간의 변화는 신호 도달 시간의 변화로 계산되어 알려진 BS의 위치로부터 UE와의 거리를 계산하는 과정에 사용할 수 있다. 제시된 알고리즘의 성능은 실제 환경에서의 상용 LTE 신호를 이용한 거리 계산 실험에 사용되어 평가되었다.

• Journal of Microbiology and Biotechnology
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• 제22권8호
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• pp.1059-1065
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• 2012

Biocatalytic transfer of oxygen in isolated cytochrome P450 or whole microbial cells is an elegant and efficient way to achieve selective hydroxylation. Cytochrome P450 CYP105P2 was isolated from Streptomyces peucetius that showed a high degree of amino acid identity with hydroxylases. Previously performed homology modeling, and subsequent docking of the model with flavone, displayed a reasonable docked structure. Therefore, in this study, in a pursuit to hydroxylate the flavone ring, CYP105P2 was co-expressed in a two-vector system with putidaredoxin reductase (camA) and putidaredoxin (camB) from Pseudomonas putida for efficient electron transport. HPLC analysis of the isolated product, together with LC-MS analysis, showed a monohydroxylated flavone, which was further established by subsequent ESI/MS-MS. A successful 10.35% yield was achieved with the whole-cell bioconversion reaction in Escherichia coli. We verified that CYP105P2 is a potential bacterial hydroxylase.