• Korean Journal of Veterinary Research
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• v.38 no.2
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• pp.239-245
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• 1998

The distributions and relative frequencies of insulin-, glucagon-, and somatostatin-immunoreactive cells in the pancreas of the duck(Anas platyrhynchos platyrhyncos, Linne) were investigated immunohistochemically on 23 days of incubation, at hatching, 1 week, 2 weeks, 3 weeks, 5 weeks, 6 weeks, 7 weeks, 9 weeks, 10 weeks, and 32 weeks after hatching. In the duck pancreas on 23 days of incubation and at hatching, mammalian type islets(mixed type) were only observed, thereafter three type's islets(mamalian, A and B type's islets) were identified. Insulin-immunoreactive cells were detected in central region of the islets, while glucagon- and somatostatin-immunoreactive cells were detected in marginal region of light(B type) or mammalian type islets, and in central region of dark islets(A type). Insulin-, and somatostatin-immunoreactive cells were also detected in the exocrine regions. In this region the insulin-immunoreactive cells were detected from 23 days of incubation to 6 weeks, however not detected after 7 weeks. At hatching the relative numbers of somatostatin-immunoreactive cells were more frequent than those of other groups, and then decreased with ages.

• Korean Journal of Environmental Agriculture
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• v.22 no.4
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• pp.290-293
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• 2003

To measure an effects of strontium on secretion of ${\alpha}$-amylase and RNase, wheat aleurone layers were isolated after the pre-incubation in a solution with or without 10 mM $SrCl_2$ or $CaCl_2$ for 3 days at $25^{\circ}C$ in the dark under aseptic conditions. The secretion of ${\alpha}$-amylase reached a maximum at 72 h after incubation. $Sr^{2+}$ induced more effectively secretion of ${\alpha}$-amylase than $Ca^{2+}$. The ${\alpha}$-amylase secretions by $Sr^{2+}$ or $Ca^{2+}$ ware about $2 (Ca^{2+})$ to $2.5 (Sr^{2+})$ fold higher than it without divalent ions, When aleurone layers were incubated without divalent ions, however, the ${\alpha}$-amylase was remarkably retained in the tissues. Total ${\alpha}$-amylase synthesis (ie. tissues + media) was slightly lowered by 10mM $SrCl_2$ addition. It seemed that the RNase secretion begins at 18 h after incubation. This meaned that the RNase secretion may process slower than ${\alpha}$-amylasee secretion. $Ca^{2+}$ effect on RNase secretion is stronger than $Sr^{2+}$ unlikely to ${\alpha}$-amylase. The secretion process is likely to be suddenly induced between 72 hand 96 h. These results suggested that the secretion was enhanced after the accumulation in aleurone layers.

• Journal of Environmental Science International
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• v.2 no.4
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• pp.255-270
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• 1993

Effects of polyamines on chlorophyll and protein content, and $\delta$-aminolevulinate dehydratase(ALAD) activity were investigated during the greening of mung bean cotyledons. Polyamines stimulated chlorophyll formation in greening cotyledons, and this effect was enhanced by KCl. The changes in protein content were similar to the changes for chlorophyll content. The excision entailed an increase in ALAD activity. Then a decrease appeared after 48 h incubation on water in the dark. It was more precocious in the light, but was accelerated when the cotyledons were illuminated after a dark preincubation. Putrescine had little effect on ALAD activity in the dark. In the light, putrescine prevented the decrease in ALAD activity and enhanced this activity when a dark preincubation preceded illumination. KCl had a slight stimulating effect in the dark, but was uneffective in the light. The combination putrescine＋KCl was devoid of stimulating effect. The results obtained suggest that plastid development of mung bean cotyledons during greening was affected by polyamines and light and that polyamines may play a role in the regulation of plastid development.

• Journal of Plant Biology
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• v.31 no.4
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• pp.299-307
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• 1988

The electron transport activities of choloroplasts isolated from hte detached rise (Oryza sativa L. cv. Chucheong) leave stored under low temperature(4$^{\circ}C$) with light illumination were investigated to understand the role of light in the low temperature inhibition of photosynthesis in the chilling-sensitive plants. Chlorophyll content of the detached leaves upon incubation at 28$^{\circ}C$ and 4$^{\circ}C$ in the dark was also measured. The rice seedlings were grown with Hoagland medium in the growth chamber of 28$^{\circ}C$ temperature and 400 ft.c fluorescent light with the photoperiod of 16 h. Although chlorophyll content of the detached leaves stored in the dark declined by 61.7% after 28$^{\circ}C$ treatement, there occurred only 5.2% decrease of chlorophyll with 4$^{\circ}C$ treatment. Low temperature treatment(4$^{\circ}C$) for 6 days brought about decreases in total photosystem(PS II＋PS I) activities by 35.2% and 73.6% in te presence and absence of light, respectively, while after 28$^{\circ}C$ treatment of the detached leaves for 6 days in the dark there was only 27.6% decrease in PS II＋PS I activity. PS II activities were also decreased by 35.6% and 72.2% in the light and dark, respectively. PS I activities were decreased slightly, however, by 7.6% and 16.2% in the light and dark, respectively. Investigations into DPClongrightarrowDCPIP and NH2OHlongrightarrowDCPIP activities revealed that low temperature inhibition of PS II activities was not due to the inactivation of the water oxidation capacity at low temperature. It was concluded that light protects the electron transport activities of isolated rice chloroplasts from the inhibitory effect of low temperature in the detached leaves.

• Journal of Photoscience
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• v.3 no.1
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• pp.1-7
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• 1996

When cucumber (Cucumis sativus L.) cotyledon discs were floated on $\delta$-aminolevulinic acid, oxyfluorfen, or rose bengal solution under light condition following 20 h dark incubation, rapid electrolyte leakage from the tissues occurred. The electrolyte leakage from the tissues was dependent on the compounds treated, their concentrations, and the duration of light exposure to the tissues. Dark incubation before exposure to continuous white light enhanced electrolyte leakage from the tissues treated with the compounds and reduced lag period for the activity of the compounds. Electrolyte leakage from the treated tissues was greatly influenced by the light intensity to which they were exposed. Higher light intensities stimulated electrolyte leakage and reduced lag period. Porphyrin biosynthesis inhibitors, gabaculine and 4,6-dioxoheptanoic acid, completely inhibited electrolyte leakage from the oxyfluorfen-treated tissues. Protection against the activity of $\delta$-aminolevulinic acid from electrolyte leakage was complete with 4,6-dioxoheptanoic acid, but not with gabaculine. However, gabaculine and 4,6-dioxoheptanoic acid gave no such protection against rose bengal activity. In summary, our results indicate that $\delta$--aminolevulinic acid, oxyfluorfen, and rose bengal exert their effects by causing electrolyte leakage from the treated tissues in a similar manner, except that oxyfluorfen has an apparent lag period for its action on electrolyte leakage increase. All above compounds require preincubation of treated tissues in darkness and subsequent light exposure with a high intensity for their maximal activities. Our results also support that in the presence of light, $\delta$-aminolevulinic acid and oxyfluorfen cause cellular damage through the indirect generation of singlet oxygen from accumulated tetrapyrroles of porphyrin pathway, whereas rose bengal causes cellular damage through the direct generation of singlet oxygen.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.23-23
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• 2017

Rice (Oryza sativa L.) is the world's most important cereal crop. In crop plant, chlorophyll content and leaf senescence could affect grain filling and yield. We analyzed a QTL associated with chlorophyll content and delayed leaf senescence using high chlorophyll near isogenic line (HC-NIL). HC-NIL derived from a cross between Oryza sativa cv. Hwaseong as a recurrent parent and wild species O. grandiglumis as a donor parent showed higher chlorophyll content than Hwaseong. To identify QTL associated with chlorophyll content, 58 $F_3$ and 38 $F_4$ lines were developed from a cross between HC-NIL and Hwaseong. For QTL analysis, simple sequence repeat (SSR) markers were used for genotyping and one-way ANOVA was conducted. A QTL for chlorophyll content (qCC2) was detected in chromosome 2 and explained 24.63% of phenotypic variation. The senescence effect of the qCC2 was examined in dark-induced incubation (DII). Detached leaves from Hwaseong and HC-NIL were incubated on 3mM MES buffer (pH 5.8) at $27^{\circ}C$ under complete dark condition. After 3 days of incubation, the Hwaseong leaves turned yellow, but the HC-NIL leaves were green. HC-NIL has higher chlorophyll content with delayed senescence than Hwaseong. These results indicated that qCC2 is associated with stay-green phenotype. To know whether the qCC2 is responsible for leaf functionality, ion leakage test and Fv/Fm measurement were performed. Both experiment results showed that differences were observed between Hwaseong and HC-NIL but it was not statistically significant. These results might suggest that the qCC2 is possibly related to chlorophyll content and non-functional stay-green phenotype.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.86-86
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• 2018

This study was conducted to investigate the effects of modified drum priming and 24-Epibrassinolide (24-EBL) treatment to improve the seed quality for export. 40, 50 and 60% seed moisture content (SMC) of hydrated seeds were incubated for 16 and 24 h in a container with a relative humidity of 99% at 26 rpm for a modified drum priming treatment. The treated seeds were sown at $20^{\circ}C$ and $30^{\circ}C$ (12/12h, light/dark) with four replications of 25 seeds on pleated paper. The seeds were hydrated with water or 24-EBL solutions of $10^{-7}$, $10^{-8}$ and $10^{-9}M$, respectively. The germination of the modified drum primed seeds (24 h incubation after 60% SMC hydration) improved to 1.6 days mean germination time (MGT) and $46%{\cdot}day^{-1}$ germination rate (GR), while the untreated seeds showed 2.1 days MGT and $28%{\cdot}day^{-1}$ GR. The modified drum priming (60% SMC and 24 h incubation with $10^{-9}M$ 24-EBL) showed improved results in MGT (1.8 days) and GR (55%) at $20^{\circ}C$, whereas untreated seeds showed 2.3 days MGT and 44% GR. Under $30^{\circ}C$, germination of modified drum primed seeds was significantly improved in GP (80%), GR ($31%{\cdot}day^{-1}$), HS (55%) and MGT (3.3 days), however, untreated seeds showed decreased GP (27%), GR ($22%{\cdot}day^{-1}$), HS (55%) and MGT (4.8 days). This study showed that the germination of lettuce seeds is enhanced by 24 h drum incubation with 24-EBL and this method can be used effectively to achieve the benefits of early germination and uniform seedling development. In addition, these treatments circumvent thermo-dormancy of lettuce seed and have a possibility of high-quality and environment-friendly seed processing.

• Journal of fish pathology
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• v.34 no.1
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• pp.105-110
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• 2021

We experienced mortality of dark-banded rockfish (Sebastes inermis) maintained in the rearing facility located in Gangneung, after transportation. Moribund fish showed various symptoms such as exophthalmia, skin ulcers, tail rots, gill rots, discoloration of liver with petechiae, yellowish fluid in intestines and ascites. Two different colonies were dominantly appeared after spreading the lesions on the agar plates and incubation. One isolate (SI_1) showed swarming movement on TSA, and formed yellow colonies on TCBS agar. The other (SI_2) showed no swarming motility and green colonies on TCBS agar. Both of them were Gram-negative. All of these results are similar with those of Genus Vibrio. They were identified as V. harveyi and V. gigantis by PCR with subsequent sequencing of 3 different genes (16 rDNA, recA, rpoA). V. harveyi is well-known as a serious pathogen of marine fish and invertebrates, while V. gigantis is known to be often isolated from marine invertebrates, but the pathogenicity is still unknown. We suspect V. harveyi as the cause of the mortality of dark-banded rockfish, but challenge experiments with these 2 Vibrio species are thought to be necessary to make a clear conclusion.

• Korean Journal of Weed Science
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• v.7 no.3
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• pp.257-264
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• 1987

Effect of various physical and chemical treatments on dark germination of Oenothera lamarckiana seeds were primarily investigated to find out factors affecting germination. Germination of seeds which did not germinate in the constant temperature and darkness was induced by several physical treatments such as sonification, wetting and drying, freezing and thawing, and removal of seed coat. Pretreatment of chilling ($4^{\circ}C$), freezing ($-10^{\circ}C$) and incubation at high temperature ($80^{\circ}C$) induced dark germination of seeds which did not germinate in the constant temperature ranges of 15 to $40^{\circ}C$ under darkness. Alternating temperature also had a stimulatory effect on dark germination of Oenothera lamarckiana seeds. Sensing of seeds to alternating temperature appeared to be completed during the first two days after imbibition. The minimum difference of temperature required for dark germination was $5^{\circ}C$ in the range of $15-25^{\circ}C$. A thiourea (1.0%) treatment induced dark germination, but GA, IAA, BA and Ethrel failed to do so.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10b
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• pp.20-20
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• 2003

Isolation and culture of leaf protoplasts from two chilli cultivars (Capsicum annuum var. accumnatum and Bird chilli) were developed to enhance selection process in the somatic hybridization programmes. In order to isolate the protoplasts from leaves of these two chilli cultivars different incubation periods (3, 5 and 10 hours) were tested with combinations of enzyme mixtures containing cellulase and macerozyme. Leaves were incubated on three enzyme mixtures (2% cellulase +0.4% macerozyme, 1% cellulase +0.2% macerozyme and 0.5% cellulase +0.1% macerozyme in 13% mannitol) at 251oC in the dark. Three hours of incubation using 2% cellulase and 0.4% macerozyme was the best for the protoplast isolation of both chilli cultivars tested. The yield was 5${\times}$108protoplasts/m1/g leaf tissue in both chilli varieties. It was found that in the mixed nurse method using Nagata and Takebe (NT) medium supplemented with 1.0mg/12,4-D, NAA and BAP with 0.5M mannitol and 1.2% Sea Plaque agarose is the best medium for protoplast culture. Protoplasts of Capsicum annum var. accumnatum were alive for 14 days forming cell walls and initiating cell division.