• Journal of Life Science
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• v.18 no.9
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• pp.1177-1185
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• 2008

In the present work, we show that spermine (spm)-induced cytotoxicity is due to the mitochondrial-dependent pathway triggered by the intracellular $Ca^{2+}$ increase in MCF-7 human breast cancer cells. Spm induced the intracellular $Ca^{2+}$ increase in a dose-dependent manner in the medium containing 1.5 mM $Ca^{2+}$. Even in the $Ca^{2+}$-free medium, spm could induce a minor $Ca^{2+}$ increase in a dose-dependent fashion, suggesting a probable leak from the internal storage. The cytotoxic effect of $Ca^{2+}$ could be further proved by using either BAPTA or ionophore. Spm-induced $Ca^{2+}$ increase led to the release of cytochrome c from mitochondria into the cytosol and the change of mitochondrial membrane potential. In MCF-7 cells, caspase-7 plays a key role in the downstream of apoptosis because caspase-3 is absent. In the cells treated with spm, the cleavage of caspase-7 and -12 was increased almost two-fold. The level of anti-apoptotic Bcl-2 protein decreased to 35% of the control; however, the cells showed increased expression of pro-apoptotic Bax protein about two-fold in response to spm. These results imply that the apoptotic signaling pathway activated by spm is likely to be mediated via the mitochondrial-dependent pathway.

• Journal of Plant Biotechnology
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• v.38 no.1
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• pp.87-93
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• 2011

S-Adenosylmethionine decarboxylase (SAMDC; EC 4.1.4.50), a key enzyme for polyamines biosynthesis, was tightly regulated for homeostatic levels. Carnation SAMDC gene (CSDC9) has an small upstream open reading frame (uORF) of 54 amino acids in 5'-leader sequence. To explore the functional mechanism of uORFs in controlling translation, we used a GUS reporter gene driven with the 35S promoter and uORF region of SAMDC gene for making transgenic tobacco plants. In our experiment, there were a translational inhibition of its downstream GUS ORF by SAMDC uORF sequence or SAMDC uORF protein. Expecially, translational inhibition was most effective in point-mutated construct, in which the start codon was changed. Therefore, this results suggested the ribosomal stalling might be involved in this translational inhibitory process. The frame shift in amino acid sequence of SAMDC uORF with start codon and stop codon resulted in a moderate increasing in GUS activity, suggesting the native amino acid sequence was important for a function as a translational inhibitor. Also, we showed that the production of GUS protein was significantly inhibited in the presence of the small uORF using histochemical analysis of GUS expression in seedlings and tobacco flowers. Importantly, the small uORF sequence induced a real peptide of 5.7 kDa, which was provided the presence of SAMDC uORF peptide band using an in vitro transcription/translation system. The peptide product of uORF might interact with other components of translational machinery as well as polyamines, which was resulted from that polyamine treatment was inhibited GUS protein band in SDS-PAGE experiment.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.1
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• pp.38-43
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• 2008

Pepper plants (Capsicum annuum, cv. Manitta) were subjected to different intensities of UV-B radiation to understand alterations of primary- and secondary-metabolism such as carbohydrates, phenolic compounds and polyamines. UV-B doses with a UV-B lamp ($1.2W\;m^{-2}$) were adjusted between 0 to 9 hr. The soluble sugars and starch contents in pepper leaves were highly influenced by UV-B treatment. The soluble sugars altered from $6.7mg\;g^{-1}\;fw$ to $5.2mg\;g^{-1}\;fw$ after 9 hrs of UV-B exposure. The starch contents after 3 hrs of UV-B exposure changed from $17.7mg\;g^{-1}\;fw$ to $12.3mg\;g^{-1}\;fw$ and then remained unchanged. The absorbance of UV-absorbing compounds reached initially maximum at all wavelengths read. On the basis of this result, we analyzed total phenolics, anthocyanin and simple free phenolic acids. Anthocyanin and free phenolic acids responded sensitively with a steady increase during UV-B treatment, although anthocyanin contents declined highly after 3 hrs of treatment. Whereas, there is no alteration of total phenolics (as gallic acid equivalent) caused by UV-B. Free polyamine levels in leaves increased rapidly and highly when UV-B was treated. The most prominent changes in polyamine induction were putrescine and spermidine (+ 70 %) after 3 hrs and spermine (+ 150 %) after 6 hrs.

• Tribology and Lubricants
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• v.30 no.4
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• pp.224-233
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• 2014

We prepared polyester-polyamines to improve the effect of carbon black dispersibility for use in thermal transfer ink, and synthesized polymeric dispersing agents by two-step reactions. In the first step, we made polyester by polycondensing 1,6-hexanediol and adipic acid. The resulting polymers had carboxylic acid, which was linked with polyamine via an acid-base reaction. We then characterized the polyester-polyamine structure by NMR spectroscopy and Fourier transform infrared spectroscopy (FT-IR). We also determined the basic characterizations such as total acid numbers (TAN) (5.0-67.5 mgKOH/g), hydroxyl values (27.1-67.5 mgKOH/g), and molar masses ($M_n=1.6-8.4kg\;mol^{-1}$) for the polyester and total base numbers (TBN) (15.3-57.1 mgKOH/g), hydroxyl values (33.0-79.8 mgKOH/g), and nitrogen contents (1.02-3.48%) for the polyester-polyamine polymers. We thus prepared thermal transfer ink using carbon blacks and the polyester-polyamine dispersing agents, and evaluated the resulting mixtures for printability, adhesive force, storage stability, ink appearance, ink gloss, and processability. These mixtures showed significant dispersibility for carbon black in the ink. Thus, we concluded that the dispersibility of the polymeric materials depended on the polyamine structure and the hydrophilicity-hydrophobicity distribution of the polymeric dispersants.

• Proceedings of the Korean Society of Crop Science Conference
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• 2003.10a
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• pp.164-165
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• 2003

• Proceedings of the Korean Society of Crop Science Conference
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• 2003.10a
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• pp.218-219
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• 2003

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.301-305
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• 1998

최근 많은 관심을 모으고 있는 폴리(트리메틸렌 테레프탈레이트)(PTMT) 섬유는 결정성고분자이면서 강도가 강하며 특히 PET 섬유가 갖고 있지 않는 고신장에서의 고탄성 회복률 등, 여러 용도로 이용할 수 있는 좋은 물성을 가지고 있으나 이의 이용 가능성에 밑받침이 될 수 있는 학술적 문헌은 주로 결정구조 및 입체배좌 그리고 기계적 성질에 관한 것들뿐이다.(중략)

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.533-538
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• 1992

The generation time of Methylobacterium extorquens AMI growing on methanol at pH 5.5 and 7.0 was found to be 23 hand 8.3 h. respectively. The bacterium grown at pH 7.0 were found to contain more amounts of spermidine and putrescine than the cell grown at pH 5.5. Cells grown at both conditions exhibited strong methanol dehydrogenase (MDH) activity at the mid-exponential growth phase. The amounts of MDH. however. were found to be almost equal through all gro~1h phases. Cells growing at the stationary phase contained large amounts of cytochrome c. The cytochrome c content was higher in cells growing at pH 7.0 than the cells growing at pH 5.5. Cells growing at pH 5.5 in the presence of putrescine or spermidine contained increased amounts of putrescine. The level of spermine, however. was decreased and that of spermidine was not changed. Spermine added into the medium was found to have no effect on the level of cellular polyamines. Putrescine or spermidine added into the medium stimulated MDH and hydroxypyruvate reductase activities. but did not affect the contents of MDH and cytochrome c. It was found that preincubation of cell-free extracts with polyamines does not stimulate MDH and hydroxypyruvate reductase activities.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.15-20
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• 2022

Aerogel is a material having a nanopore structure based on a high porosity. Due to this high porosity, it has excellent properties not found in conventional materials, but its application has been limited due to low mechanical strength. Therefore, to improve the mechanical strength of the aerogel, polyurea crosslinking was introduced and a precursor having an amine group essential for polyurea polymer formation was selected to synthesize a polyurea crosslinked aerogel composite. In addition, the crosslinking of polyurea was adjusted according to the number of amine groups present in aminosilane. It was confirmed through various analyses that the nanopore structure of the aerogel was maintained to have mesopores. The aerogel thus formed was able to improve the mechanical strength by about two times, and it was confirmed through field emission scanning electron microscope analysis that a one-dimensional polymer was formed on the silica aerogel surface through the introduction of ethylene diamine. The one-dimensional polymer thus formed has improved mechanical properties, resulting in securing an elastic modulus of about 2.66 MPa.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.10
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• pp.556-560
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• 2017

This research carried out to evaluate the disadvantage of pre-chlorination and the effect of polyamine as coagulant aids for treating the blooming water with Microcystis sp.. Pre-chlorination on blooming water makes the colony of Microcystis sp. to the smaller size. Coagulation with polyamine advanced treatment efficiency not only turbidity but also particulate matters especially less then $5{\mu}m$ size for the blooming water compared with using alum alone. Particle count was more sensitive than turbidity on water quality management of settlement and filtrate.