• Journal of Microbiology and Biotechnology
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• v.16 no.8
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• pp.1192-1200
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• 2006

An apple polygalacturonase-inhibiting protein (PGIP), which specifically inhibits endopolygalacturonase (PG, EC 3.2.1.15) from Botryosphaeria dothidea, was purified from Botryosphaeria dothidea-infected apple (Malus domestica cv. Fuji) fruits. The purified apple PGIP had a molecular mass of 40 kDa. The N-terminal amino acid sequence of the purified protein showed high homologies to those of PGIP from pear (100%), tomato (70%), and bean (65%). We also purified polygalacturonase (PG) from B. dothidea. The PG hydrolyzes pectic components of plant cell walls. When the extracted apple pectic cell wall material was treated with purified apple PGIP and B. dothidea PG, the amount of uronic acid released was lower than that treated with B. dothidea PG alone. This result demonstrates that PGIP functions specifically by inhibiting cell wall maceration of B. dothidea PG Furthermore, we characterized the de novo function of the PGIP against PG on the solubilization and depolymerization of polyuronides from cell wall of apple fruits inoculated with B. dothidea. This result demonstrated that the PGIP of plants exhibits one of the direct defense mechanisms against pathogen attack by inhibiting PGs that are released from pathogens for hydrolysis of cell wall components of plants.

• Journal of Applied Biological Chemistry
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• v.63 no.2
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• pp.117-123
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• 2020

We examined the anti-inflammatory effect of the peel extract of the newly bred Korean apple (Malus domestica Borkh.) cultivar Green ball. To test its possible use as anti-inflammatory functional material, Raw 264.7 macrophages were treated with pro-inflammatory lipopolysaccharide (LPS) in the presence or absence of Green ball apple peel ethanol extract (GBE). Notably, up to 500 ㎍/mL of GBE did not result in any signs of inhibition on cellular metabolic activity or cytotoxicity in Raw 264.7 macrophages. Supplementation with GBE to LPS-treated Raw 264.7 macrophage significantly suppressed various pro-inflammatory responses in a dose-dependent manner, including i) nitric oxide (NO) production, ii) accumulation of inducible NO synthase and cyclooxygenase-2, iii) phosphorylation of nuclear factor-kappa B (NF-κB) subunit p65, and iv) expression of pro-inflammatory biomarker genes, including tumor necrosis factor alpha, interleukin 1 beta, interleukin 6, monocyte chemoattractant protein-1, and prostaglandin E synthase 2.

• Horticultural Science & Technology
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• v.35 no.4
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• pp.410-417
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• 2017

We compared the quality of 'Fuji' apples (Malus ${\times}$ domestica) from trees whose leaves were not removed (no artificial defoliation; NAD) with apples from trees that underwent early defoliation (ED, treated in mid September and early October) and conventional defoliation (CD, treated in early and mid October). The experiment was conducted in three consecutive years using 15-year-old 'Fuji' apple grafted on Malus prunifolia. Fruits were harvested on November 7, 16 or 12 in 2011, 2012 and 2013, respectively. Compared to NAD treatment, ED and CD treatment reduced the fresh weight by 4.7% and 0.6%, respectively. The soluble solids content of NAD apples ($14.4^{\circ}Brix$) was slightly higher than that of CD ($14.1^{\circ}Brix$) and ED ($14.0^{\circ}Brix$) apples. Soluble sugar content, flesh firmness, water-core index, and titratable acidity were not affected by defoliation treatment regardless of treatment timing. The skin blush index of NAD apples (2.3) was inferior to that of CD (3.3) and ED (3.4)- treated apples. Furthermore, artificial defoliation treatments increased skin redness ($a^*$) and yellowness ($b^*$) and significantly improved the degree of skin blush compared to NAD fruits.

• Proceedings of the Korean Society of Crop Science Conference
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• 2000.11a
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• pp.103-104
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• 2000

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.357-364
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• 1999

This study measures the influence of grass cover on water use and shoot growth of apple trees growing under different soil water regimes in temperate climate conditions and evaluates monthly crop coefficients of such conditions during four months of the growing season in 1995. To do so, double pot lysimeter experiments of 3-year-old Fuji' apple (Males domestica Borkh.) trees under a transparent rain shield were designed and installed. Trees were triplicate under three soil water regimes: (A) drip-irrigation at -50 kPa of soil matric potential (IR50). (B) drip-irrigation at -80 kPa of soil matric potential (IR80), and (C) constant shallow water table at 0.45 m below the soil surface (WT45). In each treatment, two soil surface conditions were tested: the soil surface bare, and covered with turf grasses. Mean monthly water use increased with increasing soil matric potential for drip irrigation and was greatest in the WT45 treatment. Monthly crop coefficients increased linearly in time for drip-irrigated apple trees ($r^2$ values of $0.953^{***}$ for turf grass-covered system and of $0.862^{***}$ for bare surface system), while those obtained in the WT45 treatment fluctuated, Duncan's multiple range tests for shoot growth showed that grass-covered IR50 was most favorable to apple trees. while bare surface waterlogged situation was most adverse at least in part due to a lack of oxygen in the root zone. Mid-season leaf Kjeldahl-N was higher in drip-irrigated apple trees than in WT45 trees, while soil Kjeldahl-N was not different irrespective of treatments.

• The Korean Journal of Mycology
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• v.51 no.2
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• pp.111-120
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• 2023

Three fungal strains designated as KNUF-23-MG32, KNUF-23-YC8, and KNUF-23-MJ82 were isolated from the abnormal symptomatic apple trees during screening fungal pathogens collected in Jeollanam-do and Gyeongsangbuk-do, Korea. These fungal strains were found to have similar cultural and morphological characteristics close to the genus Botryosphaeria. Morphological characteristics were matched with B. kuwatsukai CBS 135219 but different with B. dothidea KACC 45481 and B. sinensis HMAS 246714^T. Pathogenicity tests of strain KNUF-23-MG32 showed that this strain causes rot in Fuji apples. Molecular phylogenetic analysis based on the sequences of the internal transcribed spacer (ITS) regions, translation elongation factor 1-alpha (TEF1α), and partial β-tubulin (TUB2) showed that these strains are B. kuwatsukai. To the best of our knowledge, this is the first report of an apple ring rot fungus Botryosphaeria kuwatsukai in Korea.

• Journal of Life Science
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• v.16 no.4
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• pp.653-658
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• 2006

An apple polygalacturonase-inhibiting protein (PGIP), that specifically inhibited endopolygalacturonase (PG, EC 3.2.1.15) from Botryosphaeria dothidea, was purified from B. dothidea infected apple (Malus domestica cv. Fuji) fruits. The apple PGIP was a mixed-type inhibitor of PG from B. dothidea. Optimal temperature for the maximum enzyme activity was $40^{\circ}C$, and optimum pH of the purified PGIP was pH 5.0. PGIP was stable up to temperature of $60^{\circ}C$ and was completely suppressed after heating at $70^{\circ}C$ for 10 min, PGIP was stable at pH between 4 and 8. Inhibition of PG by PGIP was reduced by $K^+$, $Cu^{2+}$, $Mg^{2+}$, $Ca^{2+}$ and $Zn^{2+}$ metal ion, sodium dodecyl sulfate (SDS) and 1,2-diaminocyclohexane tetra acetate (CDTA).

• Horticultural Science & Technology
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• v.31 no.1
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• pp.38-49
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• 2013

Prohexadione-calcium (Pro-Ca), ethephon and transient water stress were evaluated in a factorial design, as potential inhibitors of early-season shoot growth of high density orchard management of apple (Malus domestica Borkh.) trees. In the experiment, water stress was imposed to one-half of the 7-year-old 'Golden Delicious'/M.9 apple trees in each of 5 blocks, by stopping irrigation for 3 weeks between 35 and 56 days after full bloom (AFB). Within each whole unit, the following Pro-Ca and ethephon treatments were randomly allocated at $2{\times}2$ factorial: a) 0 or 250 $mg{\cdot}L^{-1}$ a.i. Pro-Ca applied at 28 days AFB and b) 0 or 300 $mg{\cdot}L^{-1}$ a.i. ethephon applied twice (35 and 71 days AFB). All trees were hand thinned to king flowers prior to treatments. Vegetative shoot growth was markedly reduced by Pro-Ca, with its effect being obvious within 14 days after application, while ethephon and water stress treatments were less effective. Pro-Ca had no effect on fruit set and yield but slightly increased fruit size. Ethephon substantially reduced the fruit size and yield but had no effect on fruit set. Water stress reduced fruit set, fruit size and yield. With regard to fruit quality, Pro-Ca did not influence fruit shape, flesh firmness and soluble solids contents (SSC) but slightly reduced titratable acidity. Ethephon had no effect on fruit shape but increased firmness, SSC and acidity, while water stress did not influence these fruit quality attributes. Dry weight of dormant spur buds was reduced by both Pro-Ca and water stress, while increased by ethephon. The larger dormant buds led to the larger spur flowers at the tight cluster stage the following spring. Return flowering was promoted only by ethephon, especially on previous season's shoots. There were no significant interactions between Pro-Ca and ethephon or water stress on most variables observed in this study.

• Journal of Bio-Environment Control
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• v.6 no.2
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• pp.71-79
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• 1997

Commercial Bio- Green(B.G.) functional water was manufactured through a series of processes : water - ultra-purification - adding catalysts - energy imprinting fermenting with energized water ＋ zeolite and others ＋ photosynthetic bacteria in fermenter longrightarrow filtering. Control(0), 5 or 10 liters per plant of B.G. functional water were supplied to the orchard soil under canopy of 10 year- old ‘Tsugaru’/M26 apple trees on March 20, May 20 and June 20, 1995, respectively. pH and content of Ca and Mg of orchard soil were increased by supply with B.G. functional water. However, P$_2$ $O_{5}$, K, and B contents were not influenced by the treatment. At harvest time soluble solid content of flesh tissue and anthocyanin of fruit skin were increased by the treatment. B.G functional water treatment showed higher root activities, and photosynthesis of leaves than that of control. Also B.G. functional water treatment enhanced Ca content in fruit skin and flesh tissues, whereas not affected N, K, and Mg contents. During storage at 4$^{\circ}C$ cold room, the more volume of B.G. functional water supply showed lower bitter pit symptom. Respiration and ethylene evolution in fruit decreased, while fruit firmness increased by the treatment during storage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1130-1137
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• 2016

In this study, we investigated the quality, antioxidant properties, and sensory characteristics of tofu coagulated with 'Tsugaru' apple (Malus domestica Borkh) juice. Yield, $^{\circ}Brix$, pH, total acidity, total polyphenol content, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of 'Tsugaru' apple juice were 60%, 10.3, 3.89, 0.51%, 2.26 mg gallic acid equivalent (GAE)/g, $20{\mu}g$ L-ascorbic acid equivalent (AE)/g, and $75{\mu}g$ AE/g, respectively. In case of Tofu coagulated with 20% (w/v) 'Tsugaru' apple juice, yield, $^{\circ}Brix$, pH, total acidity, hardness, chewiness, cohesiveness, total polyphenol content, ABTS radical scavenging activity, and DPPH radical scavenging activity were 165%, 6.23, 0.27%, 513 g, 315, 0.61, 12.04 mg GAE/g, $80.67{\mu}g$ AE/g, and $92.32{\mu}g$ AE/g, respectively. Both the manufacture yield and pH of tofu decreased with increasing amount of 'Tsugaru' apple juice, whereas total acidity increased. Regarding the texture and chromaticity of tofu coagulated with increasing amounts of 'Tsugaru' apple juice, hardness, chewiness, and a- and b-values increased, whereas cohesiveness and L-value both decreased. In terms of antioxidant activities, total polyphenol content and DPPH radical scavenging activity increased, whereas ABTS radical scavenging activity was maintained within a certain range. Finally, concerning the sensory evaluation (taste, color, flavor, and overall preference) of tofu coagulated with 30% (w/w) 'Tsugaru' apple juice showed the highest scores. Taken together, these results support the possible use of 'Tsugaru' apple juice in producing various foods, as addition of juice enhanced quality, antioxidant properties, and sensory characteristics of tofu.