• Journal of Microbiology and Biotechnology
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• 제22권2호
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• pp.248-255
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• 2012

In order to develop a protocol to quantify cyanobacteria and Microcystis simultaneously, the primers and probe were designed from the conserved regions of 16S rRNA gene sequences of cyanobacteria and Microcystis, respectively. Probe match analysis of the Ribosomal Database Project showed that the primers matched with over 97% of cyanobacterial 16S rRNA genes, indicating these can be used to amplify cyanobacteria specifically. The TaqMan probe, which is located between two primers, matched with 98.2% of sequences in genus GpXI, in which most Microcystis strains are included. The numbers of cyanobacterial genes were estimated with the emission of SYBR Green from the amplicons with two primers, whereas those of Microcystis spp. were measured from the fluorescence of CAL Fluor Gold 540 emitted by exonuclease activity of Taq DNA polymerase in amplification. It is expected that this method enhances the accuracy and reduces the time to count cyanobacteria and potential toxigenic Microcystis spp. in aquatic environmental samples.

• 미생물학회지
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• 제41권4호
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• pp.287-292
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• 2005

대청호에서 수화 발생이 빈번한 추소리 수역에서 2005년 3월 15일에 채취한 시료를 대상으로 유전자 분식에 의한 cyanobacteria의 다양성을 조사하였다. rpcBA-Intergenic Spacer (IGS)는 cyanobacteria에 특징적 색소인 phycocyanin을 합성하는 유전자와 유전자 사이의 부분으로, 환경시료에서 cyanobacteria의 다양성을 조사하기에 매우 유용한 기능 유전자이다. cpcBA-IGS를 이용하여 restriction fragment length polymorphism (RELP)으로 cyanobacteria의 다양성을 분석한 결과 Phomidium 속은 58 clones, Anabaena 속은 14 clones, Microcyxtis 속은 4 clones, Spirulina 속은 1 clone 그리고 uncultured cyanobacteria 2 clones가 존재하였다. 전반적으로 Phormidium 속이 우점하였으며, 여름철에 수화를 일으키는 Anabaena 속과 Microcystis 속도 많이 분포하였다. 따라서 cyanobacteria는 cpcBA-IGS와 같은 기능 유전자에 의한 종 동정 및 군집분석이 가능함을 보였다.

• Plant Biotechnology Reports
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• 제3권4호
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• pp.267-275
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• 2009

Over the years, cyanobacteria have been regarded as ideal model systems for studying fundamental biochemical processes like oxygenic photosynthesis and carbon and nitrogen assimilation. Additionally, they have been used as human foods, sources for vitamins, proteins, fine chemicals, and bioactive compounds. Aiming to increase plant productivity as well as nutritional values, cyanobacterial genes involved in carbon metabolism, fatty acid biosynthesis, and pigment biosynthesis have been intensively exploited as alternatives to homologous gene sources. In this short review, transgenic plants with cyanobacterial genes generated over the last two decades are examined, and the future prospects for transgenic crops using cyanobacterial genes obtained from functional genomics studies of numerous cyanobacterial genomes information are discussed.

• 한국미생물·생명공학회지
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• 제49권3호
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• pp.298-304
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• 2021

Photosynthetic conversion through cyanobacteria and microalgae is an increasingly serious concern in the global warming crisis. Many value-added substances are produced through strain improvement, and much research and development is being conducted to determine its potential as an actual industrial strain. Economic barriers throughout processing production can be overcome to produce value-added chemicals by microalgal strains. In this study, we engineered cyanobacteria strains for the photosynthetic production of squalene and confirmed the continuous cultivation of CO₂ and light conditions. The free-inducer system of gene expression was developed at the cyanobacterial strains. Then, the squalene production level and growth of the recombinant cyanobacteria were analyzed and discussed. For bio solar-cell factories, the ability to regulate genes based on the free-inducer gene expression system promotes metabolic engineering research and construction to produce value-added chemicals.

• 한국물환경학회지
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• 제34권6호
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• pp.661-668
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• 2018

Geosmin is volatile metabolites produced by a range of filamentous cyanobacteria which causes taste and odor problems in drinking water. Molecular ecological methods which target biosynthetic genes (geoA) are widely adopted to detect geosmin-producing cyanobacteria. The aim of this study was to investigate the potential production capability of 8 strains isolated from the Nakdong River. Ultimately, a suggestion for a genetical monitoring tool for the identification of geosmin producers in domestic waters was to be made. Geosmin was detected using solid phase microextraction gas chromatography mass spectrometry (SPME GC-MS) in two strains of Dolichospermum plactonicum (DGUC006, DGUC012) that were cultured for 28 day. The highest concentrations during the experiment period was $17,535ngL^{-1}$ and $14,311ngL^{-1}$ respectively. Additionally, geoA genes were amplified using two primers (geo78F/971R and geo78F/982R) from strains shown to produce geosmin, while amplification products were not detected in any of non-producing strains. PCR product (766 bp) was slightly shorter than the expected size for geosmin producers. According to the BLAST analysis, amplified genes were at nucleotide level with Anabaena ucrainica (HQ404996, HQ404997), Dolichospermum planctonicum (KM13400) and Dolichospermum ucrainicum (MF996872) between 99 ~ 100 %. Both strains were thus confirmed as potential geosmin-producing species. We concluded that the molecular method of analysis was a useful tool for monitoring potential cyanobacterial producers of geosmin.

• Journal of Microbiology and Biotechnology
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• 제22권1호
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• pp.118-125
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• 2012

Heat shock proteins (Hsps) play a key role in the cellular defense response to diverse environmental stresses. Here, the role of Hsp genes in the acquisition of thermotolerance in the cyanobacterium Microcystis aeruginosa NIES-298 was investigated. Twelve Hsp-related genes were examined to observe their modulated expression patterns at different temperatures (10, 15, 25, and $35^{\circ}C$) over different exposure periods. HspA and HtpG transcripts showed an up-regulation of expression at low temperatures (10 and $15^{\circ}C$) and high temperature ($35^{\circ}C$), compared with the control ($25^{\circ}C$). To examine their effects upon thermotolerance, we purified recombinant HspA and HtpG proteins. During a thermotolerance study at $54^{\circ}C$, the HspA-transformed bacteria showed increased thermotolerance compared with the control. HtpG also played a role in the defense response to acute heat stress within 30 min. These findings provide a better understanding of cellular protection mechanisms against heat stress in cyanobacteria.

• 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.

• 한국환경과학회지
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• 제32권5호
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• pp.315-328
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• 2023

Cyanobacteria have been used as pollution indicator species in freshwater ecosystems, and identifying their fluctuations can be an important part about management of surface waters globally. Cyanotoxins produced by cyanobacteria are directly or indirectly a threat to human and environmental health. In order to confirm the potential risk of these cyanotoxins, the fluctuations of phytoplankton and phylogenetic analysis of cyanotoxin synthetase genes were conducted at each point in the Yeongsan River water system in Gwangju from November 2021 to October 2022. Diatoms which grow well in winter were dominant at 99.4 ~ 99.5%, and diatoms and green algae were dominant from the spring to autumn when the water temperature rises. Stephanodiscus spp. were dominant at 92.7 to 97.5 % at all sites in the winter, and Aulacoseira spp., which grow in warm water temperatures, were dominant in summer and autumn. Microcystis aeruginosa was dominant at 25.2% in summer only at site 5. mcyB and anaC have been detected as cyanotoxin synthetase genes. The phylogenetic tree of anaC could be divided into two groups (Group 1 & Group 2). Group 1 contained Aphanizomenon sp. and Cuspidothrix issatschenkoi. It is combined with Aphanizomenon sp. and Cuspidothrix issatschenkoi, which are known to produce cyanotoxins.

• 환경생물
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• 제30권1호
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• pp.54-63
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• 2012

This study characterizes three $Anabaena$ strains and 5 $Trichormus$ strains isolated from Korean waters and 3 $Anabaena$ $flos-aquae$ strains procured from the UTEX based on morphological features and molecular analyses. The $Anabaena$ and $Trichormus$ isolates were morphologically assigned to $A.$ $variabilis$ K$\ddot{u}$tzing and $T.$ $variabilis$(K$\ddot{u}$tzing ex Bornet et Flahault) Kom$\acute{a}$rek et Anagnostidis, respectively. The $Anabaena$ and $Trichormus$ strains differed significantly in the mean length of their vegetative cells. The 16S rRNA genes from the $Anabaena$ strains showed a 100% identity to that from $A.$ $variabilis$ ATCC 29413, while the 16S rRNA genes from the $Trichormus$ strains showed a 99.9% identity to that from $T.$ $variabilis$ GREIFSWALD. The overall topology was in agreement for the 16S rRNA gene and $cpcBA$-IGS trees in the both tree-constructing methods. In a neighbor-joining tree based on the 16S rRNA gene, the 3 $Anabaena$ strains were asso-ciated with $A.$ $variabilis$, the 5 $Trichormus$ strains with $T.$ $variabilis$, and the 3 $Anabaena$ (UTEX) strains were with $Nostoc$. To date, this is the first report on $A.$ $variabilis$ and $T.$ $variabilis$ strains originating from Korea.

• Journal of Microbiology and Biotechnology
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• 제31권5호
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• pp.645-658
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• 2021

Porins are essential for the viability of Gram-negative bacteria. They ensure the uptake of nutrients, can be involved in the maintenance of outer membrane integrity and define the antibiotic or drug resistance of organisms. The function and structure of porins in proteobacteria is well described, while their function in photoautotrophic cyanobacteria has not been systematically explored. We compared the domain architecture of nine putative porins in the filamentous cyanobacterium Anabaena sp. PCC 7120 and analyzed the seven candidates with predicted OprB-domain. Single recombinant mutants of the seven genes were created and their growth capacity under different conditions was analyzed. Most of the putative porins seem to be involved in the transport of salt and copper, as respective mutants were resistant to elevated concentrations of these substances. In turn, only the mutant of alr2231 was less sensitive to elevated zinc concentrations, while mutants of alr0834, alr4741 and all4499 were resistant to high manganese concentrations. Notably the mutant of alr4550 shows a high sensitivity against harmful compounds, which is indicative for a function related to the maintenance of outer membrane integrity. Moreover, the mutant of all5191 exhibited a phenotype which suggests either a higher nitrate demand or an inefficient nitrogen fixation. The dependency of porin membrane insertion on Omp85 proteins was tested exemplarily for Alr4550, and an enhanced aggregation of Alr4550 was observed in two omp85 mutants. The comparative analysis of porin mutants suggests that the proteins in parts perform distinct functions related to envelope integrity and solute uptake.