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151.
Ismail Bezirganoglu Shaw-Yhi Hwang Tony J. Fang Jei-Fu Shaw 《Plant Cell, Tissue and Organ Culture》2013,112(2):227-237
The oriental melon (Cucumis melo L. var. makuwa cv. ‘Silver Light’) is an important fruit crop in the tropical and subtropical regions. However, oriental melon production is severely decreased by fungal diseases. In this study, antifungal protein (AFP) and chitinase (CHI) fusion genes were introduced into oriental melons to control fungal diseases caused by Rhizoctonia solani and Fusarium oxysporum. Transformation of oriental melon (Cucumis melo L. var. makuwa cv. ‘Silver Light’) with Agrobacterium tumefaciens strain LBA4404 containing antifungal protein (AFP) and chitinase (CHI) fusion genes under the control of the cauliflower mosaic virus (CaMV) 35S promoter and neomycin phosphotransferase (nptII) gene as a selectable marker was performed. Cotyledon explants of oriental melon were inoculated by Agrobacterium suspensions with pBI121–AFP–CHI and cultured in a regeneration medium. After regeneration, genomic DNA polymerase chain reaction (PCR) was conducted to confirm the presence of putative transgenic shoots. Southern blot analysis confirmed that the AFP–CHI fusion gene was incorporated into the genomic DNA of the PCR-positive lines. RT-PCR analysis showed that the AFP–CHI fusion gene was expressed in the individual transgenic lines. Western blot analysis revealed the accumulation of CHI protein in leaves. A segregation analysis of the T1 generation confirmed the inheritance of the transgene. Our results demonstrated that the AFP–CHI fusion gene was effective in protecting the transgenic melon plants against fungal disease caused by Rhizoctonia solani and Fusarium oxysporum. 相似文献
152.
Touseef Amna M. Shamshi Hassan Faheem A. Sheikh Hak Kyo Lee Kang-Seok Seo Duhak Yoon I. H. Hwang 《Applied microbiology and biotechnology》2013,97(4):1725-1734
Zinc oxide (ZnO) nanostructures have been commonly studied for electronic purposes due to their unique piezoelectric and catalytic properties; however, recently, they have been also exploited for biomedical applications. The purpose of this study was to fabricate ZnO-doped poly(urethane) (PU) nanocomposite via one-step electrospinning technique. The utilized nanocomposite was prepared by using colloidal gel composed of ZnO and PU, and the obtained mats were vacuum dried at 60 °C overnight. The physicochemical characterization of as-spun composite nanofibers was carried out by X-ray diffraction pattern, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, electron probe microanalysis, and transmission electron microscopy, whereas the thermal behavior was analyzed by thermogravimetric analysis. The viability, attachment, and proliferation of NIH 3T3 mouse fibroblast cells on the ZnO/PU composite nanofibers were analyzed by in vitro cell compatibility test. The morphological features of the cells attached on nanofibers were examined by Bio-SEM. We conclude that the electrospun nanofibrous scaffolds with unique spider nets had good biocompatibility. Cytotoxicity experiments indicated that the mouse fibroblasts could attach to the nanocomposite after being cultured. Thus, the current work demonstrates that the as-synthesized ZnO/PU hybrid nanofibers represent a promising biomaterial to be exploited for various tissue engineering applications. 相似文献
153.
H. S. Yoon Y. K. An J. H. Hwang H. S. Lim W. K. Lee K. H. Han S. H. Lee S. D. Choi 《Zeitschrift fur angewandte Ichthyologie》2013,29(2):468-469
Length–weight relationships were estimated for 14 species belonging to 13 fish families from the Suer River estuary, Korea. These 14 species are: Callionymus valenciennei, Konosirus punctatus, Conger myriaster, Cynoglossus joyneri, Tribolodon hakonensis, Thryssa hamiltonii, Acanthogobius flavimanus, Paratrypauchen microcephalus, Hexagrammos agrammus, Nuchequula nuchalis, Pseudopleuronectes yokohamae, Pennahia argentata, Sillago japonica and Takifugu niphobles. Between April 2009 and January 2010, samples were caught by commercial trawl net at depths of <20 m. Estimates for parameter b of the length–weight relationship (W = aLb) ranged between 2.510 and 3.149. 相似文献
154.
Young-Seon Lee Ona?Z. Liu Hyun?Seok Hwang Bjorn?C. Knollmann Eric?A. Sobie 《Biophysical journal》2013,104(5):1142-1150
We present a parameter sensitivity analysis method that is appropriate for stochastic models, and we demonstrate how this analysis generates experimentally testable predictions about the factors that influence local Ca2+ release in heart cells. The method involves randomly varying all parameters, running a single simulation with each set of parameters, running simulations with hundreds of model variants, then statistically relating the parameters to the simulation results using regression methods. We tested this method on a stochastic model, containing 18 parameters, of the cardiac Ca2+ spark. Results show that multivariable linear regression can successfully relate parameters to continuous model outputs such as Ca2+ spark amplitude and duration, and multivariable logistic regression can provide insight into how parameters affect Ca2+ spark triggering (a probabilistic process that is all-or-none in a single simulation). Benchmark studies demonstrate that this method is less computationally intensive than standard methods by a factor of 16. Importantly, predictions were tested experimentally by measuring Ca2+ sparks in mice with knockout of the sarcoplasmic reticulum protein triadin. These mice exhibit multiple changes in Ca2+ release unit structures, and the regression model both accurately predicts changes in Ca2+ spark amplitude (30% decrease in model, 29% decrease in experiments) and provides an intuitive and quantitative understanding of how much each alteration contributes to the result. This approach is therefore an effective, efficient, and predictive method for analyzing stochastic mathematical models to gain biological insight. 相似文献
155.
Keun Sik Baik Yeoung Min Hwang Jong-Soon Choi Joseph Kwon Chi Nam Seong 《Antonie van Leeuwenhoek》2013,104(6):1143-1150
A motile, curved to twisted rod-shaped aerobic bacterium, designated strain 04SU4-PT, was isolated from freshwater collected from the Woopo wetland (Republic of Korea). Cells were observed to be Gram-stain negative, catalase negative and oxidase positive. The major fatty acids (>10 % of the total) were identified as C19:0 ω8c cyclo (24.6 %), C16:0 (24.3 %) and C18:1 ω7c (13.1 %). The DNA G+C content was determined to be 71.5 mol%. The major polar lipids were identified as phosphatidylglycerol, phosphatidylethanolamine, one unknown phospholipid and one unknown aminolipid. The major ubiquinone was determined to be Q-10. A phylogenetic tree based on 16S rRNA gene sequences showed that strain 04SU4-PT forms an evolutionary lineage within the genus Dongia and its nearest neighbour is Dongia mobilis LM22T (98.0 % sequence similarity). Genomic DNA–DNA hybridization of stain 04SU4-PT with D. mobilis LM22T showed relatedness of only 34.2 %. The phenotypic characteristics indicate the strain 04SU4-PT can be distinguished from the sole member of the genus Dongia. On the basis of the data presented in this study, strain 04SU4-PT represents a novel species, for which the name Dongia rigui is proposed. The type strain is 04SU4-PT (KCTC 23341T = JCM 17521T). 相似文献
156.
Susan K. Boehlein Janine R. Shaw Donald R. McCarty Seon-Kap Hwang Jon D. Stewart L. Curtis Hannah 《Archives of biochemistry and biophysics》2013
ADP-glucose pyrophosphorylase (AGPase) is highly regulated by allosteric effectors acting both positively and negatively. Enzymes from various sources differ, however, in the mechanism of allosteric regulation. Here, we determined how the effector, inorganic phosphate (Pi), functions in the presence and absence of saturating amounts of the activator, 3-phosphoglyceric acid (3-PGA). This regulation was examined in the maize endosperm enzyme, the oxidized and reduced forms of the potato tuber enzyme as well as a small subunit chimeric AGPase (MP), which contains both maize endosperm and potato tuber sequences paired with a wild-type maize large subunit. These data, combined with our previous kinetic studies of these enzymes led to a model of Pi inhibition for the various enzymes. The Pi inhibition data suggest that while the maize enzyme contains a single effector site that binds both 3-PGA and Pi, the other enzymes exhibit more complex behavior and most likely have at least two separate interacting binding sites for Pi. The possible physiological implications of the differences in Pi inhibition distinguishing the maize endosperm and potato tuber AGPases are discussed. 相似文献
157.
Andrew Hollingworth Seongmin Hwang 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2013,368(1628)
We examined the conditions under which a feature value in visual working memory (VWM) recruits visual attention to matching stimuli. Previous work has suggested that VWM supports two qualitatively different states of representation: an active state that interacts with perceptual selection and a passive (or accessory) state that does not. An alternative hypothesis is that VWM supports a single form of representation, with the precision of feature memory controlling whether or not the representation interacts with perceptual selection. The results of three experiments supported the dual-state hypothesis. We established conditions under which participants retained a relatively precise representation of a parcticular colour. If the colour was immediately task relevant, it reliably recruited attention to matching stimuli. However, if the colour was not immediately task relevant, it failed to interact with perceptual selection. Feature maintenance in VWM is not necessarily equivalent with feature-based attentional selection. 相似文献
158.
Differentiation in temperature responses (survival and growth) was investigated among isolates of two tropical to temperate green algal lineages: the Cladophora vagabunda complex and the C. albida/sericea complex. The results were analysed in relation to published data on 18S rRNA and ITS sequence divergence, which have shown that the overall degree of genetic divergence is similar in the two lineages but that very different patterns of radiation have occurred. In the C. vagabunda complex, the two main clades in the well-resolved phylogenetic tree differed mainly in their tolerance to low temperatures. Within-clade variation was no stronger in the Atlantic/Pacific than in the all-Pacific clade. In the C. albida/sericea complex, six distinctive ITS types indicated early radiation. Although distinctive differences were found between some of these types, the thermal responses of others were very similar, indicating physiological stasis. In both lineages there was evidence for some adaptation to local temperature regimes but phylogenetic constraints were generally more important. Isolates with the same ITS sequences showed similar temperature responses even though collected from different climate zones. Evidence was found for a physiological trade-off between growth at high and at low temperatures in the C. albida/sericea complex, whereas, in the C. vagabunda complex, one clade showed more eurythermal growth responses than the other. In the C. vagabunda complex, which is the ancestral lineage of the C. albida/sericea complex, major differentiation was found in cold tolerance but not in heat tolerance, whereas the reverse pattern was found in the derived C. albida/sericea complex. These findings suggest that an acquisition of cold tolerance preceded the loss of heat tolerance during adaptation to colder climates. 相似文献
159.
Jeong Ah Hwang Mun Kyung Hwang Yongwoo Jang Eun Jung Lee Jong-Eun Kim Mi Hyun Oh Dong Joo Shin Semi Lim Geun og Ji Uhtaek Oh Ann M. Bode Zigang Dong Ki Won Lee Hyong Joo Lee 《The Journal of nutritional biochemistry》2013,24(6):1096-1104
Abnormal regulation of Ca2+ mediates tumorigenesis and Ca2+ channels are reportedly deregulated in cancers, indicating that regulating Ca2+ signaling in cancer cells is considered as a promising strategy to treat cancer. However, little is known regarding the mechanism by which Ca2+ affects cancer cell death. Here, we show that 20-O-β-d-glucopyranosyl-20(S)-protopanaxadiol (20-GPPD), a metabolite of ginseng saponin, causes apoptosis of colon cancer cells through the induction of cytoplasmic Ca2+. 20-GPPD decreased cell viability, increased annexin V-positive early apoptosis and induced sub-G1 accumulation and nuclear condensation of CT-26 murine colon cancer cells. Although 20-GPPD-induced activation of AMP-activated protein kinase (AMPK) played a key role in the apoptotic death of CT-26 cells, LKB1, a well-known upstream kinase of AMPK, was not involved in this activation. To identify the upstream target of 20-GPPD for activating AMPK, we examined the effect of Ca2+ on apoptosis of CT-26 cells. A calcium chelator recovered 20-GPPD-induced AMPK phosphorylation and CT-26 cell death. Confocal microscopy showed that 20-GPPD increased Ca2+ entry into CT-26 cells, whereas a transient receptor potential canonical (TRPC) blocker suppressed Ca2+ entry. When cells were treated with a TRPC blocker plus an endoplasmic reticulum (ER) calcium blocker, 20-GPPD-induced calcium influx was completely inhibited, suggesting that the ER calcium store, as well as TRPC, was involved. In vivo mouse CT-26 allografts showed that 20-GPPD significantly suppressed tumor growth, volume and weight in a dose-dependent manner. Collectively, 20-GPPD exerts potent anticarcinogenic effects on colon carcinogenesis by increasing Ca2+ influx, mainly through TRPC channels, and by targeting AMPK. 相似文献
160.
In-Kyu Hwang Shuichi Kaminogawa Kunio Yamauchi 《Bioscience, biotechnology, and biochemistry》2013,77(12):3049-3053
Some kinetic properties of a dipeptidase purified from a cell-free extract of Streptococcus cremoris H 61 were investigated. The Km values of this enzyme for various dipeptides were divided into 3 groups. Group 1 comprised mainly of neutral dipeptides, such as Leu-Gly, Leu-Leu and Leu-Ala, which had relatively low Km values (in the range 4.0-6.6 mm). Group 2 consisted of dipeptides with aromatic large amino acids either at the N- or C-terminal positions, like Leu-Phe, Phe-Ala and Leu-Tyr, which had very low Km values (in the range 1.0-2.4 mm). Group 3 was made up by dipeptides with acidic or basic amino acids at the N-terminals; His-Ala and Glu-Val were typical of this group. These had very high Km values (in the range 10–20 mm). Substantial substrate competition was found to exist in the presence of His-Ala. Bestatin inhibited the enzyme competitively with Leu-Gly and was found to have an apparent Ki value of 3.0 × 10?8 m for the enzyme. Further, the enzyme was completely inhibited by EDTA at a concentration of 2.0 × 10?5 m. On the other hand, once the activity was inhibited by EDTA, it could be restored by Co2+ and Zn2+ in the acidic pH side, and by Ca2+ and Mn2+ in the alkaline pH side. 相似文献