• 한국식품과학회지
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• 제30권5호
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• pp.1222-1228
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• 1998

스트레스에 의해서 생체는 에너지 대사를 증가시키며, 에너지 대사의 증가는 높은 반응성의 ROS를 생성한다. ROS는 높은 반응성으로 인해 지질, 단백질 등을 과산화시켜 원래의 활성을 잃게함으로 이런 ROS에 대해서 높은 소거능을 지니고 흡수가 쉬운 SOD 유사물질의 투여가 스트레스로 인한 생체내 산화적 손상을 억제할 수 있을 것으로 생각된다. 이것을 확인하기위해서 실험용 흰 쥐에게 4주간의 고정화 스트레스를 가한 결과, 체중 증가량을 감소시켰으며 스트레스 호르몬의 하나인 5-HIAA의 수준을 증가시켰다. 시험관에서 높은 항산화력을 확인한 루이보스티 추출액을 스트레스를 받은 흰 쥐에게 투여한 결과는 체중 증가량 감소는 완화시켰으나 5-HIAA의 수준을 변화시키지 못하여 스트레스 반응 자체를 억제하지 않는 것으로 판명되었다. 루이보스티의 투여는 스트레스로 인해서 유도되는 뇌 조직의 지질과산화와 단백질 산화를 억제하였으나 SOD, GPx 등의 대표적 항산화 효소 활성의 변화를 유발하지 않았다. 따라서, 루이보스티는 스트레스 반응 자체보다는 그에 따른 2차적 독성 대사산물에 대해서 효소 활성의 증가가 아닌 루이보스티 추출액의 구성분 자체가 세포를 보호한 것으로 생각되며, 루이보스티의 추출액이 열수하에서 추출된 것이기 때문에 지질과산화에 대해서보다 단백질 과산화에 대해 더 높은 보호 활성이 나타난 것으로 생각된다.

• Journal of Microbiology and Biotechnology
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• 제17권10호
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• pp.1655-1660
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• 2007

A metagenome is a unique resource to search for novel microbial enzymes from the unculturable microorganisms in soil. A forest soil metagenomic library using a fosmid and soil microbial DNA from Gwangneung forest, Korea, was constructed in Escherichia coli and screened to select lipolytic genes. A total of seven unique lipolytic clones were selected by screening of the 31,000-member forest soil metagenome library based on tributyrin hydrolysis. The ORFs for lipolytic activity were subcloned in a high copy number plasmid by screening the secondary shortgun libraries from the seven clones. Since the lipolytic enzymes were well secreted in E. coli into the culture broth, the lipolytic activity of the subclones was confirmed by the hydrolysis of p-nitrophenyl butyrate using culture supernatant. Deduced amino acid sequence analysis of the identified ORFs for lipolytic activity revealed that 4 genes encode hormone-sensitive lipase (HSL) in lipase family IV. Phylogenetic analysis indicated that 4 proteins were clustered with HSL in the database and other metagenomic HSLs. The other 2 genes and 1 gene encode non-heme peroxidase-like enzymes of lipase family V and a GDSL family esterase/lipase in family II, respectively. The gene for the GDSL enzyme is the first description of the enzyme from metagenomic screening.

• Asian-Australasian Journal of Animal Sciences
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• 제15권1호
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• pp.38-44
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• 2002

Nine crossbred castrated lambs fitted with rumen and duodenum cannula and fed a diet of hay and concentrate formulated with ground corn and soybean meal as main ingredients were used to assess the duodenal ideal amino acid pattern. Three synthetic amino acid mixtures with different profile of essential amino acids were duodenally infused in order to get three different amino acid patterns flowing into the duodenum. The mixtures were designed to have similar amino acid profile as rumen microbial protein (Pm), casein (Pc) and modified muscle amino acid (Pmm). Results showed a lower urine nitrogen excretion (p=0.05), a higher nitrogen retention (p=0.04) and bodyweight gain with treatment Pmm. The modified muscle amino acid pattern also promoted a lower ratio of Gly to other amino acids in plasma (Gly/OAA) and a higher RNA and RNA/DNA concentration in the liver of the sheep. Meanwhile, the urea concentration in plasma was reduced and the insulin concentration was increased with Pmm treatment. No differences in glucose and growth hormone concentration in plasma were found among three treatments. All results obtained indicate that the modified muscle amino acid pattern (Lys 100%, Met+Cys 39%, Thr 76%, His 41%, Arg 72%, Leu 158%, Ile 81%, Val 105%, Phe 81% and Trp 13%) was the best for growing sheep.

• 한국균학회지
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• 제21권2호
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• pp.112-119
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• 1993

식물 성장조절물질을 분비하는 미생물들을 100여주의 세균, 방선균, 균류의 분리균들로부터 탐색하였고, 그 중 뚜렷한 효과를 나타내는 균주들을 동정한 결과 Aspergillus niger로 판명되었다. 무와 오이씨의 발아는 A. niger KK, A. niger KKS와 A. niger ATCC 9642의 배양 여과액에 의하여 완전히 저해되었다. 또한 이들 세 균주들은 무우 뿌리와 하배축의 발달도 억제하였다. A. niger ATCC 26550은 하배축의 굴절을 유도하여 식물 호르몬인 오옥신과 유사한 작용을 나타내면서도, 전체 식물로는 잎의 마름도 초래하였다.

• Journal of Microbiology and Biotechnology
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• 제32권7호
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• pp.862-868
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• 2022

Microalgae are photosynthetic cyanobacteria and eukaryotic microorganisms, mainly living in the water. In agriculture, numerous studies have been conducted to utilize microalgae as a biostimulant resource. Scenedesmus has been known to be one such microalga that can promote plant growth by secretion of auxin or cytokinin hormone analogs. However, no research has been performed on the effect of microalgae treatment on plant microbiota communities. This study was conducted to investigate the mode of action of microalgae as biostimulants in a plant microbiota perspective by using Scenedesmus sp. CHK0059 (also known as species Chlorella fusca), which has been well documented as a biostimulant for strawberries. The strawberry cultivar Keumsil was bred with Seolhyang and Maehyang as the parent cultivars. Using these three cultivars, microbiota communities were evaluated for changes in structural composition according to the CHK0059 treatment. CHK0059-treated Seolhyang, and CHK0059-untreated Maehyang were similar in microbial diversity in the endosphere. From a microbiota community perspective, the diversity change showed that CHK0059 was affected by the characteristics of the host. Conversely, when CHK0059 treatment was applied, populations of Streptomyces and Actinospica were observed in the crown endosphere.

• Molecules and Cells
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• 제46권11호
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• pp.710-724
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• 2023

The plant defense responses to microbial infection are tightly regulated and integrated with the developmental program for optimal resources allocation. Notably, the defense-associated hormone salicylic acid (SA) acts as a promoter of flowering while several plant pathogens actively target the flowering signaling pathway to promote their virulence or dissemination. Ralstonia pseudosolanacearum inject tens of effectors in the host cells that collectively promote bacterial proliferation in plant tissues. Here, we characterized the function of the broadly conserved R. pseudosolanacearum effector RipL, through heterologous expression in Arabidopsis thaliana. RipL-expressing transgenic lines presented a delayed flowering, which correlated with a low expression of flowering regulator genes. Delayed flowering was also observed in Nicotiana benthamiana plants transiently expressing RipL. In parallel, RipL promoted plant susceptibility to virulent strains of Pseudomonas syringae in the effector-expressing lines or when delivered by the type III secretion system. Unexpectedly, SA accumulation and SA-dependent immune signaling were not significantly affected by RipL expression. Rather, the RNA-seq analysis of infected RipL-expressing lines revealed that the overall amplitude of the transcriptional response was dampened, suggesting that RipL could promote plant susceptibility in an SA-independent manner. Further elucidation of the molecular mechanisms underpinning RipL effect on flowering and immunity may reveal novel effector functions in host cells.

• 대한화장품학회지
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• 제46권1호
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• pp.73-80
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• 2020

심리적 스트레스는 피부의 생리적 상태에 영향을 미치고 다양한 피부 질환을 일으킬 수 있다. 스트레스 호르몬인 코티솔은 섬유질, 케라틴세포, 멜라노사이트와 같은 다양한 피부세포에 의해 분비된다. 밀착연접(tight junction, TJ) 은 포유류 피부의 과립증에서 장벽을 형성하는 세포 접합부위이다. TJ은 다른 피부 장벽기능에도 영향을 미칠 수 있으며 화학, 미생물 또는 면역학적 피부장벽에게 영향을 받는다. 스트레스로 인한 피부 장벽 손상에 관한 보고는 있지만 사람피부에서 코티솔이 TJ을 조절한다는 보고는 없다. 스트레스 호르몬 코티솔이 TJ을 조절하는 기능을 확인하기 위해 각질형성세포에 코티솔을 처리하였다. 코티솔은 TJ 구성 성분의 유전자 발현과 구조를 조절하여 피부 장벽 기능을 손상시켰다. 또한 코티솔은 인공피부 모델에서 과립층 형성을 억제하였다. 이러한 실험결과를 통해 스트레스 호르몬 코티솔이 TJ를 조절함으로써 피부 장벽 기능에 손상을 일으키는 것을 확인할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제23권5호
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• pp.644-651
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• 2013

The fermented manure derivative known as Preparation 500 is traditionally used as a field spray in biodynamic agriculture for maintaining and increasing soil fertility. This work aimed at characterizing the product from a microbiological standpoint and at assaying its bioactive properties. The approach involved molecular taxonomical characterization of the culturable microbial community; ARISA fingerprints of the total bacteria and fungal communities; chemical elemental macronutrient analysis via a combustion analyzer; activity assays for six key enzymes; bioassays for bacterial quorum sensing and chitolipooligosaccharide production; and plant hormone-like activity. The material was found to harbor a bacterial community of $2.38{\times}10^8$ CFU/g dw dominated by Gram-positives with minor instances of Actinobacteria and Gammaproteobacteria. ARISA showed a coherence of bacterial assemblages in different preparation lots of the same year in spite of geographic origin. Enzymatic activities showed elevated values of ${\beta}$-glucosidase, alkaline phosphatase, chitinase, and esterase. The preparation had no quorum sensing-detectable signal, and no rhizobial nod gene-inducing properties, but displayed a strong auxin-like effect on plants. Enzymatic analyses indicated a bioactive potential in the fertility and nutrient cycling contexts. The IAA activity and microbial degradation products qualify for a possible activity as soil biostimulants. Quantitative details and possible modes of action are discussed.

• Journal of Microbiology
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• 제38권3호
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• pp.160-168
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• 2000

A-factor I a microbial hormone that can positively control cell differentiation leading to spore formation and secondary metabolite formation in Streptomyces griseus. to identify a protease that is deeply involved in the morphological and physiological differentiation of Streptomyces, the proteases produced by Streptomyces griseus IFO 13350 and its A-factor deficient mutant strain, Streptomyces griseus HH1, as well as Streptomyces griseus HH1 transformed with the afsA gene were sturdied. In general Streptomyces griseus showed a higher degree of cell growth and protease activity in proportion to its ability to produce a higher amount of A-factor. In particular, the specific activity of the trypsin of Streptomyces griseus IFO 13350 was greatly enhanced more than twice compared with that of Streptomyces griseus HH1 in the later stage of growth. The specific activity of the metalloprotease of Streptomyces griseus HH1 was greatly enhanced more than twice compared with that of Streptomyces griseus IFO 13350, and this observation was reversed in the presence of thiostreptione, However, Streptomyces griseus HH1 transformed with the afsA gene showed a significantly decreased level of trypsin and metalloprotease activity compared with that of the HH1 strain. There was no significant difference between Streptomyces griseus IFO 13350 and HH1 strain in their chymotrypsin and thiol protease activity, yet the level of leu-amionpeptidase activity was 2 times higher in Streptomyces griseus HH1 than in strain IFO 13350 . Streptomyces griseus HH1 harboring afsA showed a similar level of enzyme activity , however, all the three protease activities sharply increased and the thiol protease activity was critically increased at the end of the fermentation. When a serine protease inhibitor, pefabloc SC, and metalloprotease inhibitor, EDTA, were applied to strain IFO 13350 to examine the in vivo effects of the protease inhibitors on the morpholofical differentiation, the formation of aerial meycelium and spores was delayed by two or three days.

• Journal of Microbiology and Biotechnology
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• 제21권12호
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• pp.1203-1210
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• 2011

Function-driven metagenomic analysis is a powerful approach to screening for novel biocatalysts. In this study, we investigated lipolytic enzymes selected from an alluvial soil metagenomic library, and identified two novel esterases, EstDL26 and EstDL136. EstDL26 and EstDL136 reactivated chloramphenicol from its acetyl derivates by counteracting the chloramphenicol acetyltransferase (CAT) activity in Escherichia coli. These two enzymes showed only 27% identity in amino acid sequence to each other; however both preferentially hydrolyzed short-chain p-nitrophenyl esters (${\leq}C_5$) and showed mesophilic properties. In vitro, EstDL136 catalyzed the deacetylation of 1- and 3-acetyl and 1,3-diacetyl derivates; in contrast, EstDL26 was not capable of the deacetylation at $C_1$, indicating a potential regioselectivity. EstDL26 and EstDL136 were similar to microbial hormone-sensitive lipase (HSL), and since chloramphenicol acetate esterase (CAE) activity was detected from two other soil esterases in the HSL family, this suggests a distribution of CAE among the soil microorganisms. The isolation and characterization of EstDL26 and EstDL136 in this study may be helpful in understanding the diversity of CAE enzymes and their potential role in releasing active chloramphenicol in the producing bacteria.