• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.3
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• pp.187-191
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• 2003

Proteolytic enzymes existing in plant cell cultured media are the major reason for the loss of secreted human granulocyte-macrophage colony-stimulating factor (hGM-CSF). The addition of pepstatin, aprotinin and PMSF relatively decreased the proteolytic degradation of hGM-CSF in a conditioned medium, but sufficient prevention against the proteolytic activity could not be obtained with chemical protease inhibitors. Gelatin, as a competitive substrate for protease, showed a stabilizing effect in a conditioned medium. Compared to the initial hGM-CSF concentration in a conditioned medium. with 10 g/L of gelatin, 68% of the hGM-CSF remained after 5 days. In a cell culture experiment, 5 g/L of gelatin significantly stimulated the hGM-CSF production and accumulation in culture media, with no growth inhibition. compared to the controls (4.72 $\mu\textrm{g}$/L), the extracellular hGM-CSF level could be increased to 39.78 $\mu\textrm{g}$/L with the addition of 5 g/L of gelatin.

• Korean journal of applied entomology
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• v.17 no.1 s.34
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• pp.33-35
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• 1978

The infected spin aches showing yellow mosaic symptom were collected and confirmed that the causal agent was turnip mosaic virus. The results of host reaction indicated that this virus induced local lesion on the inoculated leaves of Nicotiana tabacum (B.Y) and Chenopodium amaranticolor, mosaic symptoms on chrysanthemum coronarum, spinacea oleracea and Rephanus acanthiormis. The infected leaves extracts with this virus showed positive reaction with authentic turnip mosaic virus-antiserum. The virus particles were filaments type with size of 750nm by means of dipping method in electron microscope.

• Korean journal of applied entomology
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• v.17 no.1 s.34
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• pp.29-31
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• 1978

Purely isolated cucumber mosaic virus (CMV) was multiplied in Nicotiana tabacum, Ky-57 and the virus was purified by the modified method that was developed through this study. The concentration of purified CMV was 24.25 mg/ml. The purified virus, mixed with acomplet adjuvant (1: 1) was injected into rabbits intramuscularly. Two injections at 10 day interval was enough to produce a good quality antiserum. The titer of the antiserum was 1/1280 when determined by agar gell-diffusion test. The produced antisera will be used to faciliate the detection of CMV infected vegetables and other crops.

• Journal of Plant Biology
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• v.29 no.1
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• pp.1-10
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• 1986

Intra- and inter-specific protoplast fusion of tobacco (Nicotiana tabacum cv. Virginia 115) and pea (Pisum sativum cv. Sparkle) were carried out in highly inhomogeneous alternating electric fields. Under the electric field of alternating current (AC, sine wave), 600 V/cm and 800 kHz for tobacco protoplast, and 600 V/cm and 700 kHz for pea protoplasts, the protoplasts were aggregated in pearl chains. Intra-specific protoplast fusions were most effectively induced within the aggregates of tobacco and pea, respectively, by the additional application of a single high field pulse of direct current (DC, square wave) at 1 kV/cm for 50 $mutextrm{s}$. Inter-specific fusions between protoplasts of the two plants were most effectively induced in the electric field of 600 V/cm and 700 kHz, and square wave pulse at 1 kV/cm for 50 $mutextrm{s}$. The duration of the pulse over the electrical breakdown voltages was simulated from 1 to 100 $mutextrm{s}$ in both tobacco and pea protoplast. The yield of the electrofusion products was significantly high (above 60%), compared with that (20%) of the standard fusion method by polyethylene glycol (PEG) 4,000, and the viability of electrofused protoplasts was above 70%, but that of PEG-fused protoplasts 8~16%, when determined by Evan's blue staining method.

• Journal of Plant Biology
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• v.36 no.1
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• pp.113-120
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• 1993

Effects of various NaCl concentrations on salt-tolerant callus of tobacco were investigated. Selection of NaCl-tolerant (S) callus was conducted by subculturing Nicotiana tabacum cv. BY 4 callus in 200 mM NaCl-containing MS medium for more than 18 months. In spite of the long subculture period, characteristics of salt tolerance were maintained very stably. Significant differences were found in ion contents of each callus which was subcultured with treatment of various NaCl concentrations: Na+ and Cl- became higher but Mg2+, Ca2+ and K+ became lower with the increasing external salt contents. Therefore, the ratios of Na+/Ca2+ and Na+/K+ also increased resulting close to those of halophytic property. The contents of chlorophylls and carotenoids in S callus were estimated to 3.1 and 2.9 times more, respectively. than those of non-selected (NS) callus (control). The higher content of external NaCl tended to increase the amount of water soluble proteins and to decrease the amounts of the total sugars, reducing sugars and free amino acids. The activity of peroxidase was increased with higher contents of external NaCl in S callus, but it was maintained at a higher level than S callus at lower NaCl, followed by a subsequent decrease above 80 mM NaCl in NS callus. These results suggest that S callus may have a biological system converting energy source to efficient growth leading to reduction of the growth inhibition under stress environment.

• Molecules and Cells
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• v.41 no.8
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• pp.724-732
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• 2018

Plant defence responses to various biotic stresses via systemic acquired resistance (SAR) are induced by avirulent pathogens and chemical compounds, including certain plant hormones in volatile form, such as methyl salicylate and methyl jasmonate. SAR refers to the observation that, when a local part of a plant is exposed to elicitors, the entire plant exhibits a resistance response. In the natural environment, plants are continuously exposed to avirulent pathogens that induce SAR and volatile emissions affecting neighbouring plants as well as the plant itself. However, the underlying mechanism has not been intensively studied. In this study, we evaluated whether plants "memorise" the previous activation of plant immunity when exposed repeatedly to plant defensive volatiles such as methyl salicylate and methyl jasmonate. We hypothesised that stronger SAR responses would occur in plants treated with repeated applications of the volatile plant defence compound MeSA than in those exposed to a single or no treatment. Nicotiana benthamiana seedlings subjected to repeated applications of MeSA exhibited greater protection against Pseudomonas syringae pv. tabaci and Pectobacterium carotovorum subsp. carotovorum than the control. The increase in SAR capacity in response to repeated MeSA treatment was confirmed by analysing the defence priming of the expression of N. benthamiana Pathogenesis-Related 1a (NbPR1a) and NbPR2 by quantitative reverse-transcription PCR compared with the control. We propose the concept of plant memory of plant defence volatiles and suggest that SAR is strengthened by the repeated perception of volatile compounds in plants.

• The Plant Pathology Journal
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• v.18 no.6
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• pp.317-322
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• 2002

An isolate of Odontoglossum ringspot virus (ORSV) was identified from Cymbidium var. 'Grace Kelly' showing ringspot symptom on the floral and leaf parts, and was denoted as cymbidium ringspot isolate (ORSV-CR). In ultrathin sections of leaf tissue from diseased Cymbidium plants, clusters of virus particles were observed in the vacuole and cytoplasm. In the Western blot hybridization, the virus strongly reacted with ORSV-specific antiserum indistinguishable from ORSV, suggesting that the vims is serologically identical with ORSV. ORSV-CR sap was inoculated onto 20 species belonging to 12 genera. Systemic infection occurred in Cymbidium sp., Nicotiana benthamiana and N. clevelandii, the host of which was found to be different from that of ORSV-Cy, the Korean strain of ORSV. The analysis of coat protein (CP) gene showed that ORSV-CR was highly homologous to the known isolates of ORSV, with over 95.6% identity in amino acid level. Phylogenetic tree analysis of CP showed that ORSV-CR was clustered with the known ORSV isolates, suggesting that ORSV is a very stable tobamovirus.

• The Plant Pathology Journal
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• v.23 no.1
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• pp.34-36
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• 2007

Introduction of vegetatively propagated Petunia hybrids since 1992 led to increasing virus infections of propagation material. Petunia hybrid 'Surfinia' cultivated for pot-plant showed yellowing symptom along with stunt. Flowers were smaller in size and showed color-break symptom. Tobacco mosaic virus(TMV-pet) was isolated from the diseased petunia. Healthy petunia plants inoculated with TMV-pet induced mottle on leaves and color-break on flowers, and plants were stunted. Nucleotide sequences of coat protein gene amplified from RNA prepared from Nicotiana tabacum cv. Samsun infected with TMV-pet were determined(GenBank accession no. DQ981481). It showed 99.0% nucleotide sequence homology with TMV-potato3-2(GenBank accession no. AF318215) isolated from potato showing yellow mosaic and stunt symptom, and with a TMV Korean strain(GenBank accession no. X68110). This is the first reported observation of TMV from vegetatively propagated petunia in Korea.

• Journal of the Korean Society of Tobacco Science
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• v.17 no.1
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• pp.20-26
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• 1995

This study was carried out to obtain the basic data which include the change of the photosynthetic rate and protein content according to growth stage in the process of senescence of tobacco plant The photosynthetic rate was the maximum with 26.31$\mu$mol.CO2/m2.sec and stomatal resistance was the minimum with 0.2552cm/sec at 15th days after leaf emergence. However, after 50 days the photosynthesis was very little occurred. During leaf developments the number of chloroplast was increased and reached at the maximum at 25th days after emergence of leaf, thereafter, it was decreased gradually. The content of protein increased continuously and showed the highest value at 15th days after leaf emergence. The degradation rate of soluble protein was more rapid than that of insoluble protein at early stage of senescence. The range of decrement in the insoluble protein was low at late stage of senescence. The content of Rubisco, the key enzyme of photoamthesis, corresponded to about 50% of soluble protein and reached to the maximum at 150 days after leaf emergence. As the senescence progressed, the content of large subunit(UV) of Rubisco showed a tendency to decrease more rapidly than that of small subunit(SSU). The total amount of amino acids was the highest at 15th days after leaf emergence.

• Plant Biotechnology Reports
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• v.5 no.4
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• pp.301-308
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• 2011

This study tested the relative and combined efficacy of ShPx2 and ShPAL transgenes by comparing Nicotiana tabacum hybrids with enhanced levels of $_L$-phenylalanine ammonia lyase (PAL) activity and cationic peroxidase (Prx) activity with transgenic parental lines that overexpress either transgene. The PAL/Prx hybrids expressed both transgenes driven by the 35S CaMV promoter, and leaf PAL and Prx enzyme activities were similar to those of the relevant transgenic parent and seven- to tenfold higher than nontransgenic controls. Lignin levels in the PAL/Prx hybrids were higher than the PAL parent and nontransgenic controls, but not significantly higher than the Prx parent. All transgenic plants showed increased resistance to the necrotrophs Phytophthora parasitica pv. nicotianae and Cercospora nicotianae compared to nontransgenic controls, with a preponderance of smaller lesion categories produced in Prx-expressing lines. However, the PAL/Prx hybrids showed no significant increase in resistance to either pathogen relative to the Prx parental line. These data indicate that, in tobacco, the PAL and Prx transgenes do not act additively in disease resistance. Stacking with Prx did not prevent a visible growth inhibition from PAL overexpression. Practical use of ShPAL will likely require more sophisticated developmental control, and we conclude that ShPx2 is a preferred candidate for development as a resistance transgene.