• Bulletin of the Korean Chemical Society
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• 제29권6호
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• pp.1233-1242
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• 2008

The hydration effect on the intrinsic magnetism of natural salmon double-strand DNA was explored using electron magnetic resonance (EMR) spectroscopy and superconducting quantum interference device (SQUID) magnetic measurements. We learned from this study that the magnetic properties of DNA are roughly classified into two distinct groups depending on their water content: One group is of higher water content in the range of 2.6-24 water molecules per nucleotide (wpn), where all the EMR parameters and SQUID susceptibilities are dominated by spin species experiencing quasi one-dimensional diffusive motion and are independent of the water content. The other group is of lower water content in the range of 1.4-0.5 wpn. In this group, the magnetic properties are most probably dominated by cyclotron motion of spin species along the helical π -way, which is possible when the momentum scattering time (${\tau}_k$) is long enough not only to satisfy the cyclotron resonance condition (${\omega}_c{\tau}_k$ > 1) but also to induce a constructive interference between the neighboring double helices. The same effect is reflected in the S-shaped magnetization-magnetic field strength (M-H) curves superimposed with the linear background obtained by SQUID measurements, which leads to larger susceptibilities at 1000 G when compared with the values at 10,000 G. In particular, we propose that the spin-orbital coupling and Faraday's mutual inductive effect can be utilized to interpret the dimensional crossover of spin motions from quasi 1D in the hydrate state to 3D in the dry state of dsDNA.

• 한국발생생물학회지:발생과생식
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• 제19권1호
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• pp.43-51
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• 2015

Connexin (Cx) is a complex which allows direct communication between neighboring cells via exchange of signaling molecules and eventually leads to functional harmony of cells in a tissue. The initial segment (IS) is an excurrent duct of male reproductive tract and expression of numerous genes in the IS are controlled by androgens and estrogens. The effects of these steroid hormones on gene expression in the IS during postnatal development have not extensively examined. The present research investigated expressional modulation of Cx isoforms in the IS by exogenous exposure to estrogen agonist, estradiol benzoate (EB), or androgen antagonist, flutamide (Flu), at weaning age. Two different doses of EB or Flu were subcutaneously administrated in 21-day old of male rats, and expressional changes of Cx isoforms in the adult IS were analyzed by quantitative real-time PCR. Treatment of a low-dose EB ($0.015{\mu}g/kg$ body weight) resulted in an increased expression of Cx31 gene and a decreased expression of Cx37 gene. A high-dose EB ($1.5{\mu}g/kg$ body weight) treatment caused an increase of Cx31 gene expression. Increased levels of Cx30.3 and Cx40 transcripts were observed with a low-dose Flu ($500{\mu}g/kg$ body weight) treatment. Treatment of high-dose Flu (50 mg/kg body weight) led to expressional increases of Cx30.3, 40, and 43 genes. Our previous and present findings suggest differential responsiveness on gene expression of Cx isoforms in the IS by androgens and estrogens at different postnatal ages.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.260-260
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• 1999

We compared c-axis tunneling characteristics of small stacked intrinsic Josephson junctions prepared on the surface of pristine, I-, and HgI$_2$-intercalated Bi$_2Sr_2CaCu_2O_{8+x}$ (Bi2212) single crystals. The R(T) curves are almost metallic in I-Bi2212 specimens, but semiconducting in HgI$_2$-Bi2212 ones.· The transition temperatures were 82.0 K, 73.0 K, and 76.8 K for pristine Bi2212, I-Bi2212, and HgI2-Bi2212 specimens, respectively, consistent with p-T$_c$ phase diagram. Current-voltage (IV) characteristics of both kinds of specimens show multiple quasiparticle branches with well developed gap features, indicating Josephson coupling is established between neighboring CuO$_2$ planes. The critical current I$_c$ of I-Bi2212 is almost the same as of that of pristine crystals, but I$_c$ is much reduced in Hgl$_2$-Bi2212. In spite of expanded interlayer distances, the interlayer coupling is not significantly affected in I-Bi2212due to holes generated by iodine atoms. The coupling in HgI$_2$-Bi2212 is, however, weakened due to inertness of HgI$_2$ molecules and the expansion of interlayer distance. Relation between the superconducting transition temperature T$_c$ and the critical current I$_c$ seems to contradict Anderson's interlayer-pair-tunneling theory but agree with a modified version of it.

• Asian Pacific Journal of Cancer Prevention
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• 제13권3호
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• pp.873-877
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• 2012

MicroRNAs (miRNAs) are short non-coding RNA molecules characterized by their regulatory roles in cancer and gene expression. We analyzed the expression of miR-21, miR-205, and miR-342 in 59 patients with breast cancer. Samples were divided into three different groups according to their immunohistochemistry (IHC) classification: ER- positive and/or PR-positive group ($ER^+$ and/or $PR^+$; group I); HER2-positive group ($HER^{2+}$; group II); and ER/ PR/ HER2- negative ($ER^-$/ $PR^-$/ $HER^{2-}$; group III) as the triple negative group. The expression levels of the 3 miRNAs were analyzed in the tumor samples and the compared with the normal neighboring dissected tumor (NNDT) samples in all three groups. The expression of miR-21 was similar in all three groups. In patients positive for P53 by IHC, positive for axillary lymph node metastasis and higher tumor stages, it appeared to have significantly elevated. However, significant increase was not found among the 18 fibroadenoma samples. Both miR-205 and miR-342 expressions were significantly down regulated in group III. We conclude that miR-21 does not discriminate between different breast cancer groups. In contrast, miR-205 and miR-342 may be used as potential biomarkers for diagnosis of triple negative breast cancer.

• Molecules and Cells
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• 제23권2호
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• pp.228-238
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• 2007

Since molecular structure of hnRNP is not available in foreseeable future, it is best to construct a working model for hnRNP structure. A geometric problem, assembly of $700{\pm}20$ nucleotides with 48 proteins, is visualized by a frame work in which all the proteins participate in primary binding, followed by secondary, tertiary and quaternary binding with neighboring proteins without additional import. Thus, 40S hnRNP contains crown-like secondary structure (48 stemloops) and appearance of 6 petal (octamers) rose-like architectures. The proteins are wrapped by RNA. Co-transcriptional folding for RNP fibril of FMR1 gene can produce 2,571 stem-loops with frequency of 1 stem-loop/15.3 nucleotides and 53 40S hnRNP beaded structure. By spliceosome driven reactions, there occurs removal of 16 separate lariated RNPs, joining 17 separate beaded exonic structures and anchoring EJC on each exon junction. Skipping exon 12 has 5'GU, 3'AG and very compact folding pattern with frequency of 1 stem-loop per 12 nucleotides in short exon length (63 nucleotides). 5' end of exon 12 contains SS (Splicing Silencer) element of UAGGU. In exons 10, 15 and 17 where both regular and alternative splice sites exist, SS (hnRNP A1 binding site) is observed at the regular splicing site. End products are mature FMR-1 mRNP, 4 species of Pri-microRNAs derived from introns 7,9,15 and 3'UTR of exon17, respectively. There may also be some other regulatory RNAs containing ALU/Line elements as well.

• 대한화학회지
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• 제24권3호
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• pp.193-200
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• 1980

N-Acetyl-L-cysteine, $C_5H_9NO_3S,$의 결정 및 분자구조를 X-선 회절법으로 연구하였다. 이 화합물의 결정은 삼사비등축정계에 속하며 공간군은 $P_1$이다. 단위세포상수는 a = 7.04(3), b = 5.14(2), c = 8.25(3)${\AA}$, ${\alpha}$ = 106(2), ${\beta}$ = 51(1), ${\gamma}$ = 124(2)$^{\circ}$이고, 단위세포는 분자 한개만을 포함하고 있다. Weissenberg 사진촬영으로 얻은 회절반점의 총수는 629개이며 direct method를 적용하여 구조해명을 한 후 full matrix least-squares method로 정밀화하였으며 최종 R값은 0.12이다. C-카르복실기 및 N-아세틸기의 원자들은 각각 평면을 이루고 있다. 카르복실기의 산소원자 O(1)은 이웃분자의 아세틸기의 산소원자 O(3)와 $O-H{\cdot}{\cdot}{\cdot}O$ 수소결합을 하며 그 길이는 2.59${\AA}$이다.

• Journal of Korean Neurosurgical Society
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• 제60권4호
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• pp.417-423
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• 2017

Objective : Repair of sensorial nerve defect is an important issue on peripheric nerve surgery. The aim of the present study was to determine the effects of sensory-motor nerve bridging on the denervated dermatomal area, in rats with sensory nerve defects, using a neural cell adhesion molecule (NCAM). Methods : We compared the efficacy of end-to-side (ETS) coaptation of the tibial nerve for sural nerve defect repair, in 32 Sprague-Dawley rats. Rats were assigned to 1 of 4 groups : group A was the sham operated group, group B rats had sural nerves sectioned and buried in neighboring muscles, group C experienced nerve sectioning and end-to-end (ETE) anastomosis, and group D had sural nerves sectioned and ETS anastomosis was performed using atibial nerve bridge. Neurological evaluation included the skin pinch test and histological evaluation was performed by assessing NCAM expression in nerve terminals. Results : Rats in the denervated group yielded negative results for the skin pinch tests, while animals in the surgical intervention groups (group C and D) demonstrated positive results. As predicted, there were no positively stained skin specimens in the denervated group (group B); however, the surgery groups demonstrated significant staining. NCAM expression was also significantly higher in the surgery groups. However, the mean NCAM values were not significantly different between group C and group D. Conclusion : Previous research indicates that ETE nerve repair is the gold standard for peripheral nerve defect repair. However, ETS repair is an effective alternative method in cases of sensorial nerve defect when ETE repair is not possible.

• 미생물학회지
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• 제55권1호
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• pp.9-16
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• 2019

다양한 미생물은 세포와 주변의 과산화를 방지하고 여분의 에너지를 보관하기 위해 ${\alpha}$-acetolactate decarboxylase(ALDC)를 이용해 아세토인을 생성한다. 아세토인은 안전한 식품 향미 개선제이기 때문에 ALDC를 이용한 아세토인 생합성에 많은 산업체가 관심을 가지고 있다. ALDC는 ${\alpha}$-acetolactate의 탈카르복실화 반응을 통해 아세토인을 생산하는 금속 의존 효소이다. 본 논문에서는 고초균 아종 spizizenii의 ALDC(bssALDC) 결정구조를 $1.7{\AA}$ 해상도에서 보고한다. bssALDC는 두 개의 ${\beta}$-sheet가 중앙부를 형성하는 ${\alpha}/{\beta}$ 구조를 가진다. bssALDC는 중앙부의 소수성 상호작용과 주변부의 친수성 상호작용을 통해 이합체를 형성한다. bssALDC는 세 개의 histidine 잔기와 세 개의 물 분자를 이용해 아연 이온에 배위결합한다. 구조와 서열의 비교 분석에 기초하여 아연 이온과 이 주변부 bssALDC 잔기들이 bssALDC의 효소 활성부위임을 제안한다.

• Molecules and Cells
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• 제44권11호
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• pp.830-842
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• 2021

When perceiving microbe-associated molecular patterns (MAMPs) or plant-derived damage-associated molecular patterns (DAMPs), plants alter their root growth and development by displaying a reduction in the root length and the formation of root hairs and lateral roots. The exogenous application of a MAMP peptide, flg22, was shown to affect root growth by suppressing meristem activity. In addition to MAMPs, the DAMP peptide PEP1 suppresses root growth while also promoting root hair formation. However, the question of whether and how these elicitor peptides affect the development of the vascular system in the root has not been explored. The cellular receptors of PEP1, PEPR1 and PEPR2 are highly expressed in the root vascular system, while the receptors of flg22 (FLS2) and elf18 (EFR) are not. Consistent with the expression patterns of PEP1 receptors, we found that exogenously applied PEP1 has a strong impact on the division of stele cells, leading to a reduction of these cells. We also observed the alteration in the number and organization of cells that differentiate into xylem vessels. These PEP1-mediated developmental changes appear to be linked to the blockage of symplastic connections triggered by PEP1. PEP1 dramatically disrupts the symplastic movement of free green fluorescence protein (GFP) from phloem sieve elements to neighboring cells in the root meristem, leading to the deposition of a high level of callose between cells. Taken together, our first survey of PEP1-mediated vascular tissue development provides new insights into the PEP1 function as a regulator of cellular reprogramming in the Arabidopsis root vascular system.

• Molecules and Cells
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• 제39권8호
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• pp.594-602
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• 2016

Alkyl hydroperoxide reductase subunit C from Pseudomonas aeruginosa PAO1 (PaAhpC) is a member of the 2-Cys peroxiredoxin family. Here, we examined the peroxidase and molecular chaperone functions of PaAhpC using a site-directed mutagenesis approach by substitution of Ser and Thr residues with Cys at positions 78 and 105 located between two catalytic cysteines. Substitution of Ser with Cys at position 78 enhanced the chaperone activity of the mutant (S78C-PaAhpC) by approximately 9-fold compared with that of the wild-type protein (WT-PaAhpC). This increased activity may have been associated with the proportionate increase in the high-molecular-weight (HMW) fraction and enhanced hydrophobicity of S78C-PaAhpC. Homology modeling revealed that mutation of $Ser^{78}$ to $Cys^{78}$ resulted in a more compact decameric structure than that observed in WT-PaAhpC and decreased the atomic distance between the two neighboring sulfur atoms of $Cys^{78}$ in the dimer-dimer interface of S78C-PaAhpC, which could be responsible for the enhanced hydrophobic interaction at the dimer-dimer interface. Furthermore, complementation assays showed that S78C-PaAhpC exhibited greatly improved the heat tolerance, resulting in enhanced1 survival under thermal stress. Thus, addition of Cys at position 78 in PaAhpC modulated the functional shifting of this protein from a peroxidase to a chaperone.