• Journal of Photoscience
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• 제5권4호
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• pp.157-162
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• 1998

The effect of heat treatment in the light on the subsequent CO2 fixation was studied with isolated spinach chloroplasts to define the role of light during heat stress. The degree of inhibition in CO2 fixation after heat treatment at 35$^{\circ}C$ under full light intensity (600W/$m^2$) was same as that in the dark. However, heat treatment of isolated chloroplasts in the light manifested thylakoidal damage, which did not occur in the dark. Under weak light (10~30 W/$m^2$ ) where no thylakoidal damage occurred, the inhibition was substantially alleviated , showing protective effect of light . The inhibition caused by heat treatment in the dark or light is prevented by the addition of a few combined compounds to the medium prior to treatment. Fructose-1-6- bisphosphate(with aldolase)and ribose-5-phosphate, known to be effective combined with oxaloacetate in preventing inhibition after heat treatment in the dark were equally effective in the light even without oxaloacetate. Addition of sugar phosphate reduced the Mehler reaction, which may occur in fast rae under high light. However, the addition of bicarbnate and catalase that would remove Mehler reaction did not provide any protection, indicating that protective role of sugar phosphate is elsewhere. Furghermore, in whole plants rapid recovery from heat stress was observed in the light. The apparently lesser or equal inhibition in spite of additional thylakoidal damage under heat stres in the light and less requirement for the protection against heat treatment suggest that the inhibitory effect of heat stress is alleviated by light treatment.

• The Plant Pathology Journal
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• 제37권6호
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• pp.555-565
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• 2021

Bacteriophages infecting Acidovorax citrulli, the causal agent of bacterial fruit blotch, have been proven to be effective for the prevention and control of this disease. However, the occurrence of bacteriophage-resistant bacteria is one of hurdles in phage biocontrol and the understanding of phage resistance in this bacterium is an essential step. In this study, we aim to investigate possible phage resistance of A. citrulli and relationship between phage resistance and pathogenicity, and to isolate and characterize the genes involved in these phenomena. A phage-resistant and less-virulent mutant named as AC-17-G1 was isolated among 3,264 A. citrulli Tn5 mutants through serial spot assays and plaque assays followed by pathogenicity test using seed coating method. The mutant has the integrated Tn5 in the middle of a cupin protein gene. This mutant recovered its pathogenicity and phage sensitivity by complementation with corresponding wild-type gene. Site-directed mutation of this gene from wild-type by CRISPR/Cas9 system resulted in the loss of pathogenicity and acquisition of phage resistance. The growth of AC-17-G1 in King's B medium was much less than the wild-type, but the growth turned into normal in the medium supplemented with D-mannose 6-phosphate or D-fructose 6-phosphate indicating the cupin protein functions as a phosphomannos isomerase. Sodium dodecyl sulfa analysis of lipopolysaccharide (LPS) extracted from the mutant was smaller than that from wild-type. All these data suggest that the cupin protein is a phosphomannos isomerase involved in LPS synthesis, and LPS is an important determinant of pathogenicity and phage susceptibility of A. citrulli.

• 한국토양비료학회지
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• 제49권6호
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• pp.677-681
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• 2016

Excessive nitrogen fertilization influences crop yields and quality as well as environmental pollution. In this study, yields, nitrogen use efficiency and free sugar contents of burdock (Arctium lappa L.) were evaluated at different levels of nitrogen fertilization. Nitrogen fertilizer was applied at 5 levels (0, 50, 100, 150, 200%) based on the conventional fertilization ($N=230kg\;ha^{-1}$), and phosphate and potassium fertilizer were treated by conventional P and K fertilization ($P_2O_5-K_2O=140-210kg\;ha^{-1}$) in all plots. The root yields of burdock were the highest in N 100~150% treatment plots. Nitrogen use efficiency and nitrogen recovery decreased from over N 150% treatment. Nitrogen uptake of root was greater than that of shoot in N 50~200% treatments. Fructose contents in root were inversely proportional to the level of nitrogen fertilization. As considering nitrogen recovery and root quality, economical burdock yield was obtained in N $230kg\;ha^{-1}$.

• 한국식물생명공학회:학술대회논문집
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• 한국식물생명공학회 2005년도 추계학술대회 및 한일 식물생명공학 심포지엄
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• pp.9-21
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• 2005

To study the biochemical and physiological role of the plastidic glucose transporter (pGlcT) in carbohydrate metabolism, we characterized transgenic plants with mutations in the pGlcT gene (GT), gt-1 and gt-2, as well double mutants of GT and the maltose transporter (MEX1) and GT and the triose phosphate/phosphate translocator (TPT), GT and the cytosolic fructose-1,6-bisphosphatase gene (cFBP), and MEX1 and TPT, gt-1/mex2, gt-1/tpt-2, gt-1/cfbp-1, mex1-1/tpt-2, respectively. Compared to the wild type, all mutants except the gt-1/cfbp-1 mutant lines displayed higher starch accumulation and higher levels of maltose. Starch accumulation is due to a decrease in starch turnover, leading to an imbalance between the rates of synthesis and degradation. Sucrose levels of gt alleles were higher than those in wild-type plants during the light period, suggesting possible nightly supplementation via the maltose transport pathway to maintain proper carbohydrate partitioning in the plant leaves. The gt plants displayed less growth retardation than mex1-1 mutant and gt-1/mex2 double mutant displayed accumulativesevere growth retardation as compared to individual gt-1 and mex1-1 mutants, implying that the maltose transporter-mediated pathway is a major route for carbohydrate partitioning at night. The gt-1/tpt-2, mex1-1/tpt-2 and gt-1/cfbp-1 double mutants had retarded growth and low chlorophyll content to differing degrees, indicating that photosynthetic capacity had diminished. Interestingly, the gt-1/tpt-2 line displayed a glucose-insensitive phenotype and higher germination rates than wild type, suggesting its involvement not only in carbon partitioning, but also in the sugar signaling network of the pGlcT and TPT.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.822-829
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• 2007

A gene coding for phosphoketolase, a key enzyme of carbohydrate catabolism in heterofermentative lactic acid bacteria(LAB), was cloned from a Lactobacillus paraplantarum C7 and expressed in Escherichia coli. The gene is 2,502 bp long and codes for a 788-amino-acids polypeptide with a molecular mass of 88.7 kDa. A Shine-Dalgarno sequence(aaggag) and an inverted-repeat terminator sequence are located upstream and downstream of the phosphoketolase gene, respectively. The gene exhibits an identity of >52% with phosphoketolases of other LAB. The phosphoketolase of Lb. paraplantarum C7(LBPK) contains several highly conserved phosphoketolase signature regions and typical thiamine pyrophosphate(TPP) binding sites, as reported for other TPP-dependent enzymes. The phosphoketolase gene was fused to a glutathione S-transferase(GST::LBPK) gene for purification. The GST::LBPK fusion protein was detected in the soluble fraction of a recombinant Escherichia coli BL21. The GST::LBPK fusion protein was purified with a yield of 4.32mg/400ml by GSTrap HP affinity column chromatography and analyzed by N-terminal sequencing. LBPK was obtained by factor Xa treatment of fusion protein and the final yield was 3.78mg/400ml. LBPK was examined for its N-terminal sequence and phosphoketolase activity. The $K_M\;and\;V_{max}$ values for fructose-6-phosphate were $5.08{\pm}0.057mM(mean{\pm}SD)$ and $499.21{\pm}4.33{\mu}mol/min/mg$, respectively, and the optimum temperature and pH for the production of acetyl phosphate were $45^{\circ}C$ and 7.0, respectively.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1994년도 춘계학술대회 and 제3회 신약개발 연구발표회
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• pp.252-252
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• 1994

현재 시판되고 있는 정장용 생균 제제에 함유되어있는 정장균주의 하나인 Bifidohacterium bifidum은 항결핵제 중 rifampicin에 감수성으로 rifimpicin과 병용 투여시 본래의 정장 효과를 기대할 수 없다. 따라서, rifampicin에 내성인 돌연변이 균주를 얻기 위해 B. bifidum을 N-methyl-N'-nitro-N-nitroso- -guanidine(MNNG)로 처리하여 rifampicin에 내성인 30종의 균주를 선별 하였고, rifampicin에 대한 Minimal Inhibitory Concentration(MIC)를 측정해 본 결과 내성이 1,000배 이상 상승하였다. 또한 rifampicin에 내성인 균주 RFR61을 자연 돌연변이시켜 ofloxacin에도 내성인 돌연변이 균주 20종을 선별 하였고, MIC를 측정한 결과 내성이 4배 이상 증가하였다. 또, fructose-6-phosphate phosphoketolase test를 실시해 본 결과, 모두 Bifidobacterium임이 확인되었다. 유기산 생성량을 측정하여 모균주의 유기산 생성량과 가장 유사한 3균주, B. bifidum RFRll, RFR21, RFR61 그리고 OFR9을 선별하였다. 이 네 균주의 E. coli 생육 억제능을 측정한 결과 모두 모균주와 유사한 E. coli 생육 억제능을 가지고 있었다. Rifampicin 내성균주들에 대하여 내성 유지 시험을 한 결과 복귀 돌연변이에 의해 내성이 소실될 가능성은 없는 것으로 여겨진다. 마지막으로, 내성 균주에 의한 rifampicin 불활성화 여부를 알아 본 결과 rifampicin이 불활성 화되지 않음을 알 수 있었다. 이상의 결과를 통해 본 연구실에서 개발한 B. bifidum RFR11, RFR21 그리고 RFR61 균주들은 rifampicin에 내성이며, B.bifidum OFR9은 rifampicin과 ofloxacin에 이중 내성을 갖는 균주로서 모균주와 유사한 생화학적 특성을 갖는 우수한 정장 세균으로 여겨진다.

• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.388-394
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• 2005

In order to investigate the distribution of dominant Bifidobacterium species in intestinal microflora of Korean adults and seniors, SDS-PAGE profiles of whole cell proteins were used for the identification of bifidobacteria. To confirm the reliability of SDS-PAGE, the Bifidobacterium species identified by SDS-PAGE of whole cell proteins were validated by using 16S rDNA sequencing analysis. The results of SDS­PAGE corresponded well with those determined by the analysis of 16S rDNA sequencing. Based on the analysis of SDS-PAGE patterns on unidentified fecal strains which showed positive in fructose-6-phosphate phosphoketolase activity, B. adolescentis, B. longum, and B. bifidum were identified in the feces of adults, and B. adolescentis, B. longum, B. bifidum, B. breve, and B. dentium were identified in those of seniors. In most of the fecal samples tested, the predominant Bifidobacterium species consisted of only a few species, and differences in the distribution and numbers of Bifidobacterium species were observed between adults and seniors. B. adolescentis and B. longum were found to be the most common species in feces of adults, but not in seniors. Accordingly, the distribution and abundance of bifidobacteria in the human intestinal microflora varied depending on the age of hosts.

• Journal of Microbiology and Biotechnology
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• 제28권11호
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• pp.1846-1849
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• 2018

Recent human gut microbiome studies have supported that the genus Bifidobacterium is one of the most beneficial bacteria for human intestinal health. To develop a new probiotic strain for functional food applications, fourteen fecal samples were collected from healthy Koreans and the strain BCBR-583 was newly selected and isolated from a 25-year-old Korean woman's fecal sample using the selective medium for Bifidobacterium. Subsequent fructose-6-phosphate phosphoketolase (F6PPK) test and 16S rRNA gene sequencing analysis of the strain BCBR-583 confirmed that it belongs to B. longum subsp. longum. The stress resistance tests showed that it has oxygen and heat tolerance activities (5- and 3.9-fold increase for 24 h at 60 and 120 rpm, respectively; $78.61{\pm}6.67%$ survival rate at $45^{\circ}C$ for 24 h). In addition, gut environment adaptation tests revealed that this strain may be well-adapted in the gut habitat, with gastric acid/bile salt resistance ($85.79{\pm}1.53%$, survival rate under 6 h treatments of gastric acid and bile salt) and mucin adhesion ($73.72{\pm}7.36%$). Furthermore, additional tests including cholesterol lowering assay showed that it can reduce $86.31{\pm}1.85%$ of cholesterol. Based on these results, B. longum BCBR-583 has various stress resistance for survival during food processing and environmental adaptation activities for dominant survival in the gut, suggesting that it could be a good candidate for fermented food applications as a new probiotic strain.

• Biomolecules & Therapeutics
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• 제31권6호
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• pp.619-628
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• 2023

In the modern era, chronic kidney failure due to diabetes has spread across the globe. Prunetin (PRU), a component of herbal medicines, has a broad variety of pharmacological activities; these may help to slow the onset of diabetic kidney disease. The anti-nephropathic effects of PRU have not yet been reported. The present study explored the potential nephroprotective actions of PRU in diabetic rats. For 28 days, nephropathic rats were given oral doses of PRU (20, 40, and 80 mg/kg). Body weight, blood urea, creatinine, total protein, lipid profile, liver marker enzymes, carbohydrate metabolic enzymes, C-reactive protein, antioxidants, lipid peroxidative indicators, and the expression of insulin receptor substrate 1 (IRS-1) and glucose transporter 2 (GLUT-2) mRNA genes were all examined. Histological examinations of the kidneys, liver, and pancreas were also performed. The oral treatment of PRU drastically lowered the blood glucose, HbA1c, blood urea, creatinine, serum glutamic-oxaloacetic transaminase, serum glutamic pyruvic transaminase, alkaline phosphatase, lipid profile, and hexokinase. Meanwhile, the levels of fructose 1,6-bisphosphatase, glucose-6-phosphatase, and phosphoenol pyruvate carboxykinase were all elevated, but glucose-6-phosphate dehydrogenase dropped significantly. Inflammatory marker antioxidants and lipid peroxidative markers were also less persistent due to this administration. PRU upregulated the IRS-1 and GLUT-2 gene expression in the nephropathic group. The possible renoprotective properties of PRU were validated by histopathology of the liver, kidney, and pancreatic tissues. It is therefore proposed that PRU (80 mg/kg) has considerable renoprotective benefits in diabetic nephropathy in rats.

• 한국식품과학회지
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• 제8권1호
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• pp.33-41
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• 1976

1. 유기질소원(有機窒素源)으로는 soybean meal, 무기질소원(無機窒素源)으로는 $(NH_4)_2SO_4$가 lipase생산(生産)에 가장 효과(效果)이었다. 2. 배양중(培養中) 배지(培地)의 pH저하(低下)를 이르키는 xylose, glucose, fructose, galactose, mannose, maltose, soluble starch, dextrin을 탄소원(炭素源)으로 첨가(添加)하였을 때 lipase 생산(生産)이 심(甚)하게 저해(沮害)되었다. sucrose는 lipase생산(生産)을 저해(沮害)하지 않았으나 첨가효과(添加效果)는 인정(認定)되지 않았다. 3. 인산염(燐酸鹽)으로서는 $K_2HPO_4$, 마그네슘염(鹽)으로서는 $MgSO_4{\cdot}7H_2O$가 lipase생산(生産)에 가장 효과적(效果的)이었다. 4. Olive유(油), 대두유(大豆油) 및 야자유(油)의 첨가(添加)는 lipase생산(生産)을 증가(增加)시켰으며 1% olive유(油) 첨가시(添加時) lipase생산(生産)이 50% 증가(增加)되었다. 5. yeast extract $0.05{\sim}0.07%$첨가시(添加時) lipase생산(生産)이 약간 증가(增加)되었다. 6. 본균(本菌)의 lipase생산(生産)에 가장 적합(適合)한 배지(培地)는 soybean meal 2%, $K_2HPO_4$ 0.5%, $(NH_4)_2SO_4$ 0.1%, $MgSO_4{\cdot}7H_2O$ 0.05%, yeast extract 0.05%, olive유(油) 1%의 조성(組成)의 것으로서 최적배양조건하(最適培養條件下)에서 48시간(時間) 배양시(培養時)에 lipase생산(生産)이 최고(最高)에 도달(到達)하였다.