• Journal of Microbiology
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• 제38권4호
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• pp.245-249
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• 2000

Catabolic pathways for the degradation of various aromatics by Sphingomonas yanoikuyae Bl are intertwined, joining at the level of substituted benzoates, which are further degraded vita ring cleavage reactions. The mutant strain EK497, which was constructed by deleting a large DNA region containing most of the genes for biphenyl, naphthalene, m-xylene, and m-toluate degradation, was unable to grow on all of the aromatics tested except for benzoate as the sole source of carbon and energy.S. yanoikuyae EK497 was found to possess only catechol ortho-ring cleavage activity due to deletion of the genes for the meta-cleavage pathway. Wild-type S. yanoikuyae Bl grown on benzoate has both catechol orthoand meta-cleavage activity. However, m-xylene and m-toluate, which are metabolized through methylbenzoate, and biphenyl, which is metabolized through benzoate, induce only the meta-cleavage pathway, suggesting the presence of a substrate-dependent induction mechanism.

• Journal of Microbiology and Biotechnology
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• 제5권2호
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• pp.68-73
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• 1995

Pseudomonas sp. P20 was shown to be capable of degrading biphenyl and 4-chlorobiphenyl (4CB) to produce the corresponding benzoic acids wnich were not further degraded. But the potential of the strain for biodegradation of 4CB was shown to be excellent. The pcbA, B, C and D genes responsible for the aromatic ring-cleavage of biphenyl and 4CB degradation were cloned from the chromosomal DNA of the strain. In this study, the pebC and D genes specifying degradation of 2, 3-dihydroxybiphenyl (2, 3-DHBP) produced from biphenyl by the pebAB-encoded enzymes were cloned by using pBluescript SK(＋) as a vector. From the pCK102 (9.3 kb) containing pebC and D genes, pCK1022 inserted with a EcoRI-HindIII DNA fragment (4.1 kb) carrying pebC and D and a pCK1092 inserted with EcoRI-XbaI fragment (1.95 kb) carrying pebC were constructed. The expression of pcbC and D' in E. coli CK102 and pebC in E. coli CK1092 was examined by gas chromatography and UV-vis spectrophotometry. 2.3-dihydroxybiphenyl was readily degraded to produce meta-cleavage product (MCP) by E. coli CK102 after incubation for 10 min, and then only benzoic acid(BA) was detected in the 24-h old culture. The MCP was detected in E. coli CK1022 containing pebC and 0 genes (by the resting cells assay) for up to 3 h after incubation and then diminished completely in 8 h, whereas the MCP accumulated in the E. coli CK1092 culture even after 6 h of incubation. The 2, 3-DHBP dioxygenases (product of pebC gene) produced by E. coli CK1, CK102, CK1023, and CK1092 strains were measured by native PAGE analysis to be about 250 kDa in molecular weight, which were about same as those of Pseudomonas sp. DJ-12, P. pseudoa1caligenes KF707, and P. putida OU83.

• Journal of Microbiology and Biotechnology
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• 제10권2호
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• pp.258-263
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• 2000

2-Hydroxy-6-oxo-6phenylhexa-2,4-dienoate (HOPDA) hydrolase catalyzes the hydrolytic cleavage of HOPDA to bemzpate and 2-hydroxypenta-2, 4-dienoate (HPD) during microbial catabolism of biphenyl and polychlorinated biphenyls. A HOPDA hydrolase gene (pcbD) was isolated from the genomic library of Pseudomonas sp. P20 and designated as pCNUO1201; a 7.5-kb XbaI DNA fragment from Pseudomonas sp. P20 was inserted into the pBluescript SK(+) XbaI site. E. coli HB101 harboring pCNU1201 exhibited HOPDA hydrolase activity. The open reading frame (ORF) corresponding to the pcbD gene consisted of 855 base pairs with an ATG initiation codon and a TGA termination codon. The ORF was preceded by a rebosome-binding sequence of 5'-TGGAGC-3' and its G+C content was 55 mol%. The pcbD gene of Pseudomonas sp. P20 was located immedeately downstream of the pcbC gene encoding 2,3- dihydroxybiphenyl 1,2-dioxygenase, and approximately 4-kb upstream of the pcbE gene encoding HPD hydratase. The pcbK gene was able to encode a polypeptide with a molecular weight of 31,732 containing 284 amino acid residues. The deduced amino acid sequence of the HOPDA hydrolase of Pseudomonas sp. P20 exhibited high identity (62%) with those of the HOPDA hydrolases of P. putida KF715, P. pseudoalcaligenes KF707, and Burkholderia cepacia LB400, and also significant homology with those of other hydrolytic enzymes including esterase, transferase, and peptidase.

• 한국잡초학회지
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• 제32권2호
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• pp.133-138
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• 2012

본 시험은 SU계 제초제 저항성 잡초의 발생이 전국적으로 문제가 되면서 새로운 작용기작을 가지는 4-HPPD 저해제인 tefuryltrione의 SU계 제초제 저항성 논잡초에 대한 야외 포장에서의 약효와 벼에 대한 선택성을 확인하고자 수행되었다. Tefuryltrione 단제로 이앙 10~15일 후에 처리하였을 때 피에 대해서는 약효가 미흡하였으나, mefenacet과의 합제에서는 피뿐만 아니라 올챙이고랭이와 물달개비에 대해서 매우 우수한 약효를 보였다. 특히, 일년생 뿐 아니라 지하부로도 월동을 하는 다년생 올챙이고랭이에 대해서도 우수한 약효가 있는 것을 확인할 수 있었다. 경기도 평택의 바이엘크롭사이언스(주) 기술연구소 시험 포장 등 3개시험 포장에서 제초제 저항성 초종인 미국외풀, 알방동사니, 마디꽃 등과 가막사리, 사마귀풀, 여뀌바늘 등에 대해서도 mefenacet+tefuryltrione 합제는 매우 우수한 약효를 보였다. 일반 벼 품종인 추청벼와 동진벼를 대상으로 시험한 결과 초기에 약간의 생육억제를 보이지만 회복되어 처리 후 20일 이후에는 별다른 문제가 없었다.

• Journal of Microbiology and Biotechnology
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• 제9권6호
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• pp.804-810
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• 1999

There is a possibility that carvone, a monoterpene from spearmint (Mentha spicata), could induce the bph degradative pathway and genes in Alcaligenes eutrophus H850, which is a known Gram-negative PCB degrader with a broad substrate specificity that was thoroughly investigated with Arthrobacter sp. BIB, a Gram-positive PCB degrader. The strains BIB and H850 were unable to utilize and grow on the plant terpene [(R)-(-)-carvone] (50ppm) to be recognized as a sole carbon source. Nevertheless, the carvone did induce 2,3-dihydroxybiphenyl 1,2-dioxygenase (encoded by bphC) in the strain B lB, as observed by a resting cell assay that monitors accumulation of a yellow meta ring fission product from 4,4'-dichlorobiphenyl (DCBp). The monoterpene, however, did not appear to induce the meta cleavage pathway in the strain H850. Instead, an assumption was made that the strain might be using an alternative pathway, probably the ortho-cleavage pathway. A reverse transcription (RT)-PCR system, utilizing primers designed from a conserved region of the bphC gene of Arthrobacter sp. M5, was employed to verify the occurrence of the alternative pathway. A successful amplification (182bp) of mRNA transcribed from the N-terminal region of the bphC gene was accomplished in H850 cells induced by carvone (50ppm) as well as in biphenyl-growth cells. It is, therefore, likely that H850 possesses a specific PCB degradation pathway and hence a different substrate specificity compared with B1B. This study will contribute to an elucidation of the dynamic aspects of PCB bioremediation in terms of roles played by PCB degraders and plant terpenes as natural inducer substrates that are ubiquitous and environmentally compatible.

• IMMUNE NETWORK
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• 제20권5호
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• pp.38.1-38.12
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• 2020

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that initiate both T-cell responses and tolerance. Tolerogenic DCs (tDCs) are regulatory DCs that suppress immune responses through the induction of T-cell anergy and Tregs. Because lactoferrin (LF) was demonstrated to induce functional Tregs and has a protective effect against inflammatory bowel disease, we explored the tolerogenic effects of LF on mouse bone marrow-derived DCs (BMDCs). The expression of CD80/86 and MHC class II was diminished in LF-treated BMDCs (LF-BMDCs). LF facilitated BMDCs to suppress proliferation and elevate Foxp3⁺ induced Treg (iTreg) differentiation in ovalbumin-specific CD4⁺ T-cell culture. Foxp3 expression was further increased by blockade of the B7 molecule using CTLA4-Ig but was diminished by additional CD28 stimulation using anti-CD28 Ab. On the other hand, the levels of arginase-1 and indoleamine 2,3-dioxygenase-1 (known as key T-cell suppressive molecules) were increased in LF-BMDCs. Consistently, the suppressive activity of LF-BMDCs was partially restored by inhibitors of these molecules. Collectively, these results suggest that LF effectively causes DCs to be tolerogenic by both the suppression of T-cell proliferation and enhancement of iTreg differentiation. This tolerogenic effect of LF is due to the reduction of costimulatory molecules and enhancement of suppressive molecules.

• 한국잡초학회지
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• 제31권2호
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• pp.192-198
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• 2011

서해안 간척지대를 중심으로 최근에는 경기, 충청 지역까지도 문제가 되고 있는 다년생의 난방제 잡초인 SU계 제초제 저항성 새섬매자기에 대하여 pyrimisulfan+mefenacet SC, triafamone+tefuryltrione GR와 HPPD 저해제인 tefuryltrione GR를 SU계 제초제인 pyriminobac-methyl+pyrazosulfuron-ethyl GR와 대조약제로 하여 온실과 포장에서 확인하였다. 생육기의 새섬매자기에 대해서 온실 및 포장조건에서 pyrimisulfan+mefenacet SC와 triafamone+tefuryltrione GR은 SU계 제초제 저항성 새섬매자기에 대해 95% 이상의 방제효과를 보여주었다. 두 약제에 의해 새섬매자기는 생육이 억제되어 갈변, 괴사하였다. Tefuryltrione GR는 생육 초기에는 새섬매자기에 대해서 80% 내외의 약효와 백화 증상을 확인할 수 있었으나, 재생 및 후발아하는 새섬매자기에 대해서는 방제효과가 68%로 떨어졌다. 경기 김포, 평택, 충남 당진, 서산, 전남 해남 지역 등의 새섬매자기 다발생 지역에서도 pyrimisulfan+mefenacet SC는 발생 초기의 새섬매자기는 물론 생육기의 새섬매자기에 대해서도 우수한 방제효과를 보였다.

• Journal of Microbiology and Biotechnology
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• 제22권3호
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• pp.283-291
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• 2012

Bioremediation efforts often rely on the application of surfactants to enhance hydrocarbon bioavailability. However, synthetic surfactants can sometimes be toxic to degrading microorganisms, thus reducing the clearance rate of the pollutant. Therefore, surfactant-resistant bacteria can be an important tool for bioremediation efforts of hydrophobic pollutants, circumventing the toxicity of synthetic surfactants that often delay microbial bioremediation of these contaminants. In this study, we screened a natural surfactant-rich compartment, the estuarine surface microlayer (SML), for cultivable surfactant-resistant bacteria using selective cultures of sodium dodecyl sulfate (SDS) and cetyl trimethylammonium bromide (CTAB). Resistance to surfactants was evaluated by colony counts in solid media amended with critical micelle concentrations (CMC) of either surfactants, in comparison with non-amended controls. Selective cultures for surfactant-resistant bacteria were prepared in mineral medium also containing CMC concentrations of either CTAB or SDS. The surfactantresistant isolates obtained were tested by PCR for the Pseudomonas genus marker gacA gene and for the naphthalene-dioxygenase-encoding gene ndo. Isolates were also screened for biosurfactant production by the atomized oil assay. A high proportion of culturable bacterioneuston was tolerant to CMC concentrations of SDS or CTAB. The gacA-targeted PCR revealed that 64% of the isolates were Pseudomonads. Biosurfactant production in solid medium was detected in 9.4% of tested isolates, all affiliated with genus Pseudomonas. This study shows that the SML is a potential source of surfactant-resistant and biosurfactant-producing bacteria in which Pseudomonads emerge as a relevant group.

• Journal of Ginseng Research
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• 제46권1호
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• pp.62-70
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• 2022

Background: Maternal Toxoplasma gondii (T. gondii) infection during pregnancy has been associated with various mental illnesses in the offspring. Ginsenoside Rh2 (GRh2) is a major bioactive compound obtained from ginseng that has an anti-T. gondii effect and attenuates microglial activation through toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) signaling pathway. GRh2 also alleviated tumor-associated or lipopolysaccharide-induced depression. However, the effects and potential mechanisms of GRh2 on depression-like behavior in mouse offspring caused by maternal T. gondii infection during pregnancy have not been investigated. Methods: We examined GRh2 effects on the depression-like behavior in mouse offspring, caused by maternal T. gondii infection during pregnancy, by measuring depression-like behaviors and assaying parameters at the neuronal and molecular level. Results: We showed that GRh2 significantly improved behavioral measures: sucrose consumption, forced swim time and tail suspended immobility time of their offspring. These corresponded with increased tissue concentrations of 5-hydroxytryptamine and dopamine, and attenuated indoleamine 2,3-dioxygenase or enhanced tyrosine hydroxylase expression in the prefrontal cortex. GRh2 ameliorated neuronal damage in the prefrontal cortex. Molecular docking results revealed that GRh2 binds strongly to both TLR4 and high mobility group box 1 (HMGB1). Conclusion: This study demonstrated that GRh2 ameliorated the depression-like behavior in mouse offspring of maternal T. gondii infection during pregnancy by attenuating the excessive activation of microglia and neuroinflammation through the HMGB1/TLR4/NF-κB signaling pathway. It suggests that GRh2 could be considered a potential therapy in preventing and treating psychiatric disorders in the offspring mice of mothers with prenatal exposure to T. gondii infection.

• 한국잡초학회지
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• 제31권4호
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• pp.384-393
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• 2011

Benzobicyclon은 HPPD활성을 억제하여 plastoquinone의 생합성을 저해하며 최종적으로 carotenoid 합성을 억제하고 대상잡초는 백화현상(bleaching)을 거쳐 고사하게 된다. 본 시험은 저항성잡초에 대한 benzobicyclon의 제형별, 증량제 종류별 제초활성을 비교하기 위하여 실시하였다. 폿트 시험에서 SU계 제초제 저항성 올챙이고랭이에 대한 benzobicyclon의 제형별 제초활성은 SC가 GR보다 높게 나타났고 이러한 결과는 시험포장에서도 동일하였는데, 이는 SC의 평균입경이 GR보다 작기 때문이다. 또한 평균입경이 동일한 benzobicyclon 혼합제의 DT와 GR간의 제초활성은 차이는 용출속도에 의해 차이가 나타났다. Benzobicyclon 혼합제 GR를 분쇄방법을 통해 유효성분의 평균입경을 각각 다르게 하여 제초활성을 비교시 습식분쇄를 거쳐 평균입경을 작게 한 GR-II의 제초활성이 높았다. 또한 건식분쇄를 거쳐 증량제를 talc와 bentonite로 사용한 GR-I보다 증량제를 $CaCO_3$와 kaolin을 사용한 GR-III의 제초활성이 10% 높았다. Benzobicyclon 성분을 습식분쇄하여 제형화한 GR의 제초활성이 높은 이유는 benzobicyclon 성분의 평균 입경이 작아 유효성분의 용출이 신속하게 이루어졌기 때문이고, 증량제의 종류에 따른 용출 차이는 benzobicyclon의 광물질의 종류에 따라 흡착(결합)력이 다르기 때문이다. Benzobicyclon 혼합제의 스크린 사이즈가 1mm인 GR-I와 0.7mm인 GR-IV간의 효과차이는 10% 이내이었다.