• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.294-299
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• 2000

In order to find out the effects of shading and nitrogen fertilization on the accumulation of $NO_3\;^-$ in leaves of lettuce, lettuce plants were cultivated in the pots under glasshouse condition with different rates of shading(0, 50%) and nitrogen fertilization(100, 180, 200, 300, $400\;kg{\cdot}ha^{-1}$). The pH value was lower in soil after experiment than before experiment, whereas, contents of EC and $NO_3-N$ were higher. As the amounts of nitrogen fertilization were increased, pHs were decreased, but EC and the contents of $NO_3-N$ were increased. At the nitrogen fertilizations of 100, 180, 200, 300 and $400\;kg{\cdot}ha^{-1}$, the germination rates of lettuce were decreased to 84, 78, 76, 72 and 74%, and survival rates were also decreased to 94, 94, 90, 60 and 46%, respectively. However, the fresh weight of lettuce was highest at $45\;g{\cdot}plant^{-1}$ in the recommended fertilizer $plot(180\;kg{\cdot}ha^{-1})$ with non-shading condition. The contents of $NO_3\;^-$ in the leaves of lettuce were increased 2.8-4.1 times under 50% shading conditions than that under non-shading condition. It kept increasing up to seven order of growth phase; however, it started to decrease after eight order phase. Nitrate reductase activity of lettuce in non-shading condition was higher than that in 50% shading condition.

• Korean Journal of Plant Tissue Culture
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• v.21 no.1
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• pp.15-22
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• 1994

To understand the molecular mechanism of hardening process in somatic embryo development and artificial seed germination in celery (Apium graveolens L.), the changes of protein synthesis by ABA or cold teatment at early globular stage were examined. Protein content and nitrate reductase activity in ABA- or cold-treated somatic embryo and seedlings were higher than that in unheated ones. The protein content and nitrate reductase activity were more prominent in somatic embryos than in seedlings. From two-dimensional electrophoresis, several protein spots specific to ABA or cold treatment were identified: 30 KD, 32 KD, 171 KD and 205 KD at heart-shaped stage; and 29 KD, 33 KD, 37 KD, 38 KD, 41 KD, 55 KD, 66 KD, and 110 KD at cotyledonary stage were the most specifically synthesized However the synthesis of certain polypeptides were repressed at heart-shaped or cotyledonary stage: 42 KD, 44 KD, 59 KD, 64 KD, 101 KD, 104 KD, and 190 KD at heart-shaped stage; and 29 KD and 116 KD at cotyledonary stage. The protein pattern changes by ABA or cold treatment occurred simultaneously and mainly in acid-soluble proteins during somatic embryo development and artificial seed germination. Therefore it is suggested that the metabolic changes for adaptation to environmental change occur during somatic embryo development and the germination and growth of seedling from embryo.

• Korean Journal of Microbiology
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• v.55 no.1
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• pp.69-73
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• 2019

During screening of microbes for compounds having cosmetic benefits, we isolated Marinobacter salarius HL2708#2 from lava seawater on Jeju Island, Republic of Korea. The complete genome sequence was determined. Strain HL27080#2 features a circular chromosome of 4,304,603 bp with 57.21% G+C content and a 244,163 bp plasmid with 53.14% G+C. There were 4,180 protein coding sequences identified, along with 49 transfer RNA and 18 ribosomal RNA noncoding genes. The genome harbored genes for the utilization of alcohol, maltose/starch, and monosaccharide as sole carbon sources. Genes responsible for halophilic characteristics and heavy metal resistance could be annotated, as well as aromatic and alkane hydrocarbons. Contrary to the prior report that M. salarius is negative for nitrate and nitrite reduction, nitrate/nitrite reductase along with nitrate/nitrate transporters and nitronate monooxygenase were evident, suggesting that strain HL2708#2 may be able to denitrify extracellular nitroalkenes to ammonia.

• The Plant Pathology Journal
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• v.22 no.3
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• pp.222-229
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• 2006

Twenty-two isolates of Fusarium oxysporum f. sp. fragariae were obtained from diseased strawberry plants and their characteristics were investigated by vegetative compatibility group (VCG), random amplified polymorphic DNA (RAPD), and pathogenicity. Three major VCGs (A, B, and C) and one incompatible group were identified by nitrate reductase complementation test. The virulence pattern of the 22 isolates was studied in relation to four cultivars including Dochiodome, Red-pearl, Maehyang and Akihime. RAPD markers were used to determine genetic relationship, and created three major clusters among the 22 isolates of F. oxysporum f. sp. fragariae. Isolates belong to VCG-C were strongly pathogenic, and relatively high correlation was existed among VCG and RAPD, and virulence. In addition, VCG and RAPD pattern between pathogenic and non-pathogenic isolates were distinctly different.

• Asian Journal of Turfgrass Science
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• v.3 no.2
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• pp.95-111
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• 1989

야외 조건에서 생장한 한국산 들잔디(Zoysia japonica Steud)의 잎, 줄기, 뿌리, 지하경의 관부와 절간에 있어서 질산환원효소 활성도(NRA)와 전분분해효소의 활성도(AA)를 측정하였다. 각 기관에서의 효소 활성도는 4월 중순부터 증가하여 6월의 개화기때 최대값에 도달하였다. 그후 효소 활성도는 급격히 감소하여 겨울철에는 최소에 이르렀다. 이 결과는 잔디의 각 기관에서 NR과 Amylase는 계절적 활성변이를 가진다는 것을 제안한다. NR과 Amylase가 낮은 활성도를 가지는 1986년 7월 31일에 6cm의 높이에서 잔디의 지상부를 예초(cuting)한 결과, 모든 기관에서의 AA와 잎, 줄기에서의 NRA는 2일간의 지연기 후에 급격히 증가하여 7일째에 최대에 이르렀다. 이 값은 대조구의 효소 활성도 보다 약 3배 높았고, 계절적 변이에서의 최대 활성도의 약 90%에 도달하였다. 예초된 잎에서의 조단백질(CP)의 함량은 예초후 7일째 까지 증가하였으나, 건물생산량(DM)과 총가용성 탄수화물(TSC) 함량은 예초후 4,5일 동안 감소하다가 다시 증가하여 7일째에 예초전의 수준에 도달한 후 일정한 값을 유지하였다. 또한 각 기관에서의 NRA와 AA는 예초후 8일째에 정상 수준으로 급감하였다. 이 결과는 완전히 자란 잔디 자체는 NR과 Amylase의 활성에 대한 억제제로서 작용하며, cutting과 같은 외부 성처요인이 개체 수준에서 적용되었을때 손상된 물질을 회복하기 위하여 분자 수준에서 수준에서 효소가 활성화 된다는 것을 제안한다.

• Biomolecules & Therapeutics
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• v.23 no.2
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• pp.180-188
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• 2015

This study investigated the possible effects and molecular mechanisms of diallyl disulfide (DADS) against cyclophosphamide (CP)-induced hemorrhagic cystitis (HC) in rats. Inflammation response was assessed by histopathology and serum cytokines levels. We determined the protein expressions of nuclear transcription factor kappa-B (NF-${\kappa}B$), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), oxidative stress, urinary nitrite-nitrate, malondialdehyde (MDA), and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Finally, we studied the involvement of mitogen-activated protein kinases (MAPKs) signaling in the protective effects of DADS against CP-induced HC. CP treatment caused a HC which was evidenced by an increase in histopathological changes, proinflammatory cytokines levels, urinary nitrite-nitrate level, and the protein expression of NF-${\kappa}B$, COX-2, iNOS, TNF-${\alpha}$, p-c-Jun N-terminal kinase (JNK), and p-extracellular signal regulated kinase (ERK). The significant decreases in glutathione content and glutathione-S-transferase and glutathione reductase activities, and the significant increase in MDA content and urinary MDA and 8-OHdG levels indicated that CP-induced bladder injury was mediated through oxidative DNA damage. In contrast, DADS pretreatment attenuated CP-induced HC, including histopathological lesion, serum cytokines levels, oxidative damage, and urinary oxidative DNA damage. DADS also caused significantly decreased the protein expressions of NF-${\kappa}B$, COX-2, iNOS, TNF-${\alpha}$, p-JNK, and p-ERK. These results indicate that DADS prevents CP-induced HC and that the protective effects of DADS may be due to its ability to regulate proinflammatory cytokines production by inhibition of NF-${\kappa}B$ and MAPKs expressions, and its potent anti-oxidative capability through reduction of oxidative DNA damage in the bladder.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1211-1216
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• 2004

A MNNG (N-methyl-N'-nitro-N-nitrosoguanidine) induced chromium resistant strain ($Cr^{r}18$) of unicellular cyanobacterium Anacystis nidulans has been isolated and characterized. The resistant strain could grow (although restricted to $50\%$ of control) in chromium concentration (180${\mu}M$) lethal to the wild-type. Sublethal ($160{\mu}M$) concentration of $Cr^{6+}$ significantly reduced (13-$37.5$) all the photosynthetic pigments of A. nidulans with maximum reduction in phycoerythrin followed by ChI $\alpha$. Pigments of A. nidulans were drastically decreased in lethal concentration of Cr^{6+} with maximum reduction in phycoerythrin ($75\%$) and allophycocyanin ($67.5\%$). Resistant strain $Cr^{r}18$ resisted toxic effects of sublethal and lethal concentrations of $Cr^{6+}$ on photosynthetic pigments as revealed by less decrease in pigments as compared to A. nidulans. Effect of $Cr^{6+}$ stress was also studied on nitrogen assimilation and phosphate uptake. Sublethal concentration of $Cr^{6+}$ drastically reduced ($71.5\%$) nitrate uptake by A. nidulans while a decrease of $29\%$ was observed in strain $Cr^{r}18$. Short (2 day) exposure of A. nidulans and its resistant strain $Cr^{r}18\;to\;Cr^{6+}$ did not affect nitrate reductase and glutamine synthetase (transferase), whereas longer (10 day) exposure to $Cr^{6+}$ lowered activities of both enzymes in A. nidulans but not significantly in the strain $Cr^{r}18$. Ammonium uptake by both strains was not affected by $Cr^{6+}$. Thus, $Cr^{6+}$ affected photosynthetic pigments, nitrogen assimilation, and phosphate uptake of A. nidulans, while strain $Cr^{r}18$ was able to resist toxic effects of the metal. Advantages of using strain $Cr^{r}18$ for bioremediation purposes have been evaluated by studying $Cr^{6+}$ removal from the solution. Resistant strain $Cr^{r}18$ was able to remove $33\%$ more $Cr^{6+}$ than A. nidulans and thus it can prove to be a good candidate for bioremediation of $Cr^{6+}$ from polluted waters.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.210-217
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• 2011

In an effort to isolate novel bacteria for the bioremediation of over-fertilized soils, we identified 135 denitrifying cells out of 3,471 oligotrophic bacteria pools (3.9%) using a denitrification medium supplemented with potassium nitrate as the sole nitrogen source. Soil samples were taken from ecologically well-conserved areas, including a mountain swamp around the demilitarized zone (Yongneup), two ecoparks (Upo and the Mujechi bog), and ten representative islands around the Korean peninsula (Jejudo, Daecheongdo, Socheongdo, Baekryeongdo, Ulrungdo, Dokdo, Geomundo, Hongdo, Huksando and Yeonpyeongdo). All of the 135 bacteria produced nitrogen gas from the denitrification medium, and were proved to be nitrate reductase positive by API-BioLog tests. Phylogenetic analysis using 16S rDNA sequences revealed that the 135 bacteria consisted of 44 different genera. Along with the most prominent, Proteobacteria (87.4%), we identified denitrifying bacteria from Firmicutes (9.4%), Actinobacteria (2.4%), and Bacteroidetes (0.8%). Physiological analyses of the 44 representative denitrifying bacteria, under various pH levels, growth temperatures and salt stresses, revealed 12 favorable denitrifying strains for soil bioremediation.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.36-43
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• 2016

With transient flooding followed by poor or slow drainage plant roots may become reduction conditions because the root zone was fully filled with water. This study was examined the effects of calcium treatment in the early growth stage on biochemical changes in leaves and roots of melon (Cucumis melo L.) seedlings kept under flooding condition for 72 h. The activities of lactate dehydrogenase more gradually enhanced in the roots than those of leaves of melon seedlings treated with calcium. The activities of alcohol dehydrogenase associated with alcohol fermentation under low oxygen conditions continuously increased in the leaves and roots of seedlings untreated with calcium under flooding at least 72 h but those was constant within at least 12 h in treated with calcium. These results showed that calcium supplying in the early growth stage mitigated alcohol fermentation of melon seedlings kept under flooding condition for 72 h. Activities of nitrate reductase and acid phosphatase in the leaves and roots of seedlings in treated with calcium somewhat higher than those of non-treated with calcium. The activities of sucrose phosphate synthase and fructose-1,6-bisphosphatase of leaves of seedlings in treated with calcium more higher than those of non-treated with calcium. These results indicated that calcium nutrition mitigate the reduction of activities of some enzymes of melon seedling kept under flooding condition for 72 h.

• The Korean Journal of Pesticide Science
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• v.12 no.4
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• pp.335-341
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• 2008

In this study, hexaconazole 5% SC, an ergosterol biosynthesis inhibitor, was tested on groundnut with its recommended ($500\;mL\;ha^{-1}$) and higher ($2,000\;mL\;ha^{-1}$) concentrations under greenhouse conditions in India. Its influence on biochemical constituents of groundnut plants was assessed apart from its disease management potential against late leaf spot caused by Phaeoisariopsis personata (Berk and Curt). Likewise, leaf samples were collected from hexaconazole 5% SC-sprayed plants at different time intervals. Thereafter, their analyses showed considerable differences in the plant constituents, such as chlorophyll, soluble protein, and total phenol contents and the activity of nitrate reductase enzyme. The induction activity of defense-related enzyme, peroxidase, was also analyzed. However, no difference was observed in the isozymic pattern. Moreover, the ground kernels collected from treated plants also showed no difference in the estimated carbohydrate and other constituents.