• Title/Summary/Keyword: Biophysics

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Membrane Topology of Helix 0 of the Epsin N-terminal Homology Domain

  • Kweon, Dae-Hyuk;Shin, Yeon-Kyun;Shin, Jae Yoon;Lee, Jong-Hwa;Lee, Jung-Bok;Seo, Jin-Ho;Kim, Yong Sung
    • Molecules and Cells
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    • v.21 no.3
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    • pp.428-435
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    • 2006
  • Specific interaction of the epsin N-terminal homology(ENTH) domain with the plasma membrane appears to bridge other related proteins to the specific regions of the membrane that are invaginated to form endocytic vesicles. An additional $\alpha$-helix, referred to as helix 0 (H0), is formed in the presence of the soluble ligand inositol-1,4,5-trisphosphate [$Ins(1,4,5)P_3$] at the N terminus of the ENTH domain (amino acid residues 3-15). The ENTH domain alone and full-length epsin cause tubulation of liposomes made of brain lipids. Thus, it is believed that H0 is membrane-inserted when it is coordinated with the phospholipid phosphatidylinositol-4,5-bisphosphate [$PtdIns(4,5)P_2$], resulting in membrane deformation as well as recruitment of accessory factors to the membrane. However, formation of H0 in a real biological membrane has not been demonstrated. In the present study, the membrane structure of H0 was determined by measurement of electron paramagnetic resonance (EPR) nitroxide accessibility. H0 was located at the phosphate head-group region of the membrane. Moreover, EPR line-shape analysis indicated that no pre-formed H0-like structure were present on normal acidic membranes. $PtdIns(4,5)P_2$ was necessary and sufficient for interaction of the H0 region with the membrane. H0 was stable only in the membrane. In conclusion, the H0 region of the ENTH domain has an intrinsic ability to form H0 in a $PtdIns(4,5)P_2$-containing membrane, perhaps functioning as a sensor of membrane patches enriched with $PtdIns(4,5)P_2$ that will initiate curvature to form endocytic vesicles.

Production of Bio-ethanol from Brown Algae by Physicochemical Hydrolysis (물리화학적 가수분해에 의한 갈조류 바이오 에탄올 생산)

  • Lee, Sung-Mok;Kim, Jae-Hyeok;Cho, Hwa-Young;Joo, Hyun;Lee, Jae-Hwa
    • Applied Chemistry for Engineering
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    • v.20 no.5
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    • pp.517-521
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    • 2009
  • In this study, the productivity of bio-ethanol obtained from various brown-algae raw materials was examined. Brown-algae polysaccharide, consisting of alginate and laminaran, is usable for the effective production of bio-ethanol if it is hydrolyzed to monomer unit. The objective of this study is the production of bio-ethanol from brown-algae using a heat-treatment and acid-treatment. Bio-ethanol was produced by Saccharomyces cerevisiae KCCM1129 and Pachysolen tannophilus KCTC 7937 strains. Laminaran japonica was higher than Sagassum fulvellum and Hizikia fusiformis, Laminaran japonica optimum pre-treatment is used to derive the ethanol production of Saccharomyces cerevisiae KCCM1129 and Pachysolen tannophilus KCTC 7937 respectively 9.16 g/L, 9.80 g/L. The maximum output of Sargassum fulvellum and Hizikia fusiformis was very low as 0.22 g/L.

Antioxidant, Antimicrobial, and Cytotoxic Activities of Ovotransferrin from Egg White

  • Moon, Sun-Hee;Lee, Jae-Hoon;Lee, Yong-Ju;Paik, Ji-Yeon;Ahn, Dong-Uk;Paik, Hyun-Dong
    • Food Science of Animal Resources
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    • v.32 no.5
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    • pp.612-617
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    • 2012
  • The antioxidant, antimicrobial, and cytotoxic activities of ovotransferrin were investigated in vitro. The antioxidant capacity of ovotransferrin was evaluated using the 2,2-Diphenyl-1-picryl hydrazyl (DPPH) radical scavenging method, antimicrobial effects using the agar well diffusion method, and cytotoxicity using the 3-(4,5-dimethylthizol-2-yl)-2,5-diphenylatetetrazolium bromide (MTT) assay. The DPPH radical-scavenging capacity of ovotransferrin at 1 mg/mL level reached approximately 60% after 48 h of reaction. The antimicrobial effects of ovotransferrin against common food-borne pathogens, Staphylococcus aureus KCCM 32395, Bacillus cereus KCCM 40935, Listeria monocytogenes ATCC 15313, Escherichia coli O157:H7 ATCC 43895, and Helicobacter pylori HpKCTC 26695 were dose dependant. Gram-positive bacteria was more sensitive to ovotransferrin than gram-negative bacteria. Ovotransferrin showed stronger antimicrobial effect against L. monocytogenes than other gram-positive bacteria tested. The cytotoxicity of ovotransferrin was evaluated in human cancer cell lines, various tissue origins, including the larynx (Hep-2), stomach (AGS), lung (SK-MES-1), liver (HepG2), breast (MCF-7), cervix (HeLa), and colon (HT-29). Ovotransferrin displayed relatively high cytotoxicity (${\leq}60%$ inhibition effects) at 40 mg/mL. At lower concentrations (${\leq}10mg/mL$), however, ovotransferrin cytotoxic effects were not significant in all cancer cell lines tested. These results indicated that ovotransferrin has potential to be used as an antioxidant or antimicrobial agent in foods or a pharmaceutical agent against cancers.

Effects of standardized extracts of Lamium album and Urtica dioica on rat tracheal smooth muscle contraction

  • Arefani, Samane;Mehran, Seyyed Mohammad Mohseni;Moladoust, Hassan;Norasfard, Mohammad Reza;Ghorbani, Ahmad;Abedinzade, Mahmood
    • Journal of Pharmacopuncture
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    • v.21 no.2
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    • pp.70-75
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    • 2018
  • Objective: Diseases of the respiratory system are one of the main causes of death and include situation such as chronic obstructive pulmonary disease, pneumonia or asthma. Medicinal plants have beneficial effects on multiple diseases include respiratory disorders like asthma and bronchitis. The aim of this study was to evaluate the effects of U. dioica and L. Album on tracheal smooth muscle contraction. Material and methods: Hydroalcoholic extracts of L. Album and U. Dioica aerial parts were prepared by maceration method and standardized based on their total phenol content. The effect of the extracts on the KCl-induced contraction of rat trachea was examined in an organ bath chamber. Data was analyzed with spss software 22. Results: The extract of L. Album (5 mg/ml), similar to theophylline (20 mM), significantly reduced the KCl-induced tracheal contraction. On the other hand, U. Dioica (1 mg/ml and 5 mg/ml) augmented the KCl-induced contraction. Conclusion: The relaxant effect of L. Album on the trachea makes it as a candidate for the managing patients with asthma and obstructive pulmonary diseases. But because of U. Dioica potential constrictive effect on the trachea it is suggested that patients avoid consuming it.

Ginseng for Reducing the Blood Pressure in Patients with Hypertension: A Systematic Review and Meta-Analysis

  • Hur, Myung-Haeng;Lee, Myeong-Soo;Yang, Hye-Jeong;Kim, Chan;Bae, Ik-Lyul;Ernst, Edzard
    • Journal of Ginseng Research
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    • v.34 no.4
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    • pp.342-347
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    • 2010
  • Ginseng is one of the most-widely used herbal remedies. This systematic review evaluates the current evidence for its use in the reducing blood pressure (BP) in patients with hypertension. Systematic searches of 12 electronic databases were conducted without language restrictions. All randomized clinical trials (RCTs) of ginseng as a treatment for hypertension were candidates for inclusion. Methodological quality was assessed using the Cochrane risk of bias. Five RCTs met the inclusion criteria. The risk of bias was low in most of the trials. Four of the included RCTs compared the effectiveness of ginseng to placebo. The meta-analysis of these data failed to show a statistically significant acute effect on systolic BP (SBP) or diastolic BP (DBP). However, subgroup analyses showed beneficial effects of Korean red ginseng (KRG) on both SBP (n=54, mean difference [MD], -6.52; 95% confidence interval [CI], -9.99 to -3.04; p=0.0002) and DBP (n=54, MD, -5.21; 95% CI, -7.90 to -2.51; p=0.0001). Two RCTs tested the long-term effects of ginseng for BP for 24hours. One of these trials failed to show any benefits of KRG compared to no treatment, and the other failed to show superior effects of North American ginseng compared to placebo. Adverse events with ginseng were none in one trial or not assessed. Collectively, these RCTs provide limited evidence for the acute effectiveness of KRG in the treatment of high BP. The total number of RCTs included in the analysis and the total sample size were insufficient to draw definitive conclusions. More rigorous studies are warranted.

Crystal structure of CodW in Bacillus Subtilis - the first N-terminal serine pretense

  • Park, Seong-Hwan;Park, Hyun-Ho;Lim, Young-Jun;Kang, Min-Suk;Lim, Byung-Kook;Seong, Ihn-Sik;Jimin Wang;Chung, Chin-Ha;Eom, Soo-Hyun
    • Proceedings of the Korea Crystallographic Association Conference
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    • 2002.11a
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    • pp.25-25
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    • 2002
  • CodWX, encoded by the cod operon in Bacillus subtilis, is a member of the ATP-dependent protease complex family, and is homologous to the eukaryotic 26S proteasome. It consists of two multimeric complexes: two hexameric ATPase caps of CodX and a protease chamber consisting of CodW dodecamer. Prior structural studies have shown that the N-terminal threonine residue is solely functional as a proteolytic nucleophile in ATP-dependent proteases such as HslV and certain β-type subunits of 20S proteasome, which have a primary sequence similarity of -50% and -20% with CodW respectively. Here we present a 3.0 Å resolution crystal structure of CodW, which is the first N-terminal serine protease among the known proteolytic enzymes. In spite of the same fold and the conserved contacts between subunits with HslV in E. coli and H. influenza, this structure shows the five additional residues extending from conserved Thr1 among the other ATP-dependent pretense and extraordinary basic proteolytic chamber.

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Biophysical Characteristics of Meridian System with Two Pain Diseases (통증에 따른 경락의 생체 물리적 정보 분석 연구)

  • Kaptchuk, Ted J.;Nam, Bong-Hyun
    • Korean Journal of Acupuncture
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    • v.22 no.4
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    • pp.29-41
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    • 2005
  • Objectives : Although previous anatomic, physiological and biophysics studies have examined the acupuncture meridian system, much remains unclear and controversial. This study was undertaken to examine electrical potential aspects of the meridian system. Electric potential was measured at the well and sea acupoints on the twelve acupuncture meridians (AM), on forty patients half with loin lesions, and pain of loin and lower extremities(LL) and half with shoulder lesions, and aching of shoulder and arm(SA). The object was to determine to what extent electric potential is an important risk factor between LL and SA. Methods : At the left and the right side with each of twenty LL and twenty SA patients, physiograph was used to measure electric potentials of AM ten sessions. T-test was used to compare the mean of electric potential between the two different pain groups and multiple logistic regression was used to analyze the risk of the 24 electric potentials measured. Results and Conclusions : In the LL, the only electric potential that was statistically significantly greater than SA was the bladder meridian on the left side. On the contrary, electric potentials in SA, which includes the large intestine, pericardium, triple burner, spleen, stomach, kidney and gallbladder meridians, were statistically larger than those of LL at the same side. On the right side, the five kinds of electric potentials(lung, large intestine, small intestine, pericardium and gallbladder meridian) of LL were statistically larger than those of SA. On the triple burner, stomach and kidney meridians electric potentials of SA were larger than those in LL. After adjusting for 24 electric potentials, pain risk factors, and different illness categories, multiple stepwise selection logistic regression modeling, resulted in the final selection of a total of 13 statistically significant electric potentials. These were 7 electric potentials at left side - small intestine, triple burner, spleen, stomach, bladder, liver and gallbladder meridian, and 6 at rght side - lung, large intestine, heart, pericardium, kidney and bladder meridian.

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High-level production and initial crystallization of a Fe65 PTB domain (Fe65단백질의 한 PTB 도메인에 대한 과발현 및 초기 결정화)

  • Ro, Seung-Hyun;Ha, Nam-Chul
    • Journal of Life Science
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    • v.17 no.1 s.81
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    • pp.18-23
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    • 2007
  • Fe65, a neuron-specific adaptor protein, has two phosphotyrosine binding (PTB) domains. The second PTB (PTB2) domain interacts with intracellular domain fragment (AICD) of amyloid beta precursor protein (APP). Recent studies suggested that tile complex is composed of AICD and Fe65 transactivates genes that are responsible for neuronal cell death in Alzheimer's disease (AD). Therefore, a compound inhibiting the interaction between Fe65 and AICD can be a drug candidate to treat AD. However, it remains unclear how Fe65 recognizes AICD at a molecular level. Here, we report high-level production of the PTB2 domain of Fe65 in the baculovirus system. We found that the baculovirus system is an efficient method to obtain the Fe65 PTB2 domain, compared with the bacterial and mammalian expression systems. The purified recombinant protein was used for crystallization to determine its crystal structure helping to understand the molecular mechanism of Fe65-dependent signaling and to design its inhibitors.

Characteristics of Hypoxic Pulmonary Vasoconstriction of the Rat: Study by the Vessel Size and Location in the Lung

  • Lee, Sang-Jin;Kim, Ki-Whan
    • The Korean Journal of Physiology and Pharmacology
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    • v.3 no.3
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    • pp.321-328
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    • 1999
  • Pulmonary blood vessels with diameters of $200{\sim}400\;{\mu}m$ produce considerably more force in response to vasoconstrictor drugs than those which are either smaller or larger. We have therefore investigated whether or not hypoxic pulmonary vasoconstriction (HPV) is more powerful in vessels of these diameters. We have also looked at the possibility that vessels from different regions of the lung respond differently. To do this we have grouped vessels according to their location within the lung as well as by size. We used a small vessel myograph (Cambustion AM10, Cambridge, UK) to study 208 preconstricted $(1\;{\mu}M\;PGF_{2{\alpha}})$ small pulmonary arteries $(300{\sim}800\;{\mu}m$ diameter when stretched to a tension equivalent to 25 mmHg transmural pressure) from 39 rats anaesthetized with 2% inspired halothane. A biphasic contraction was observed in response to hypoxia (ca. 25 mmHg $Po_2).$ The magnitudes of both the first, transient, phase (PT, peak tension) and of the second, sustained, phase (SST, steady state tension) were measured. The latter was measured 40 min after the start of hypoxia. The first phase was most pronounced in vessels with an average diameter of 423 ${\mu}m$ while the second phase was most pronounced in larger vessels (mean diameter 505 ${\mu}m).$ These maximal responses were all seen in vessels somewhat larger than reported by others. The responses of smaller vessels $(400{\sim}500\;{\mu}m)$ did not depend upon their location within the lung, but those of larger vessels $(600{\sim}700\;{\mu}m)$ showed regional differences. Those from the right lobe and those from the base of the lung gave the largest responses. It was especially noticeable that large vessels (631 ${\mu}m$ diameter) from the base of the right lung gave the biggest responses. Thus HPV seems to occur not in a uniform manner, dependent solely to the size of vessels, but it also depends to some degree on the region of the lung from which vessels have been taken. Furthermore, our results suggest that larger vessels, as well as smaller ones, may contribute significantly to HPV.

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Regulation of Magnesium Release by cAMP during Chemical Hypoxia in the Rat Heart and Isolated Ventricular Myocytes

  • Kim, Jin-Shang;Scarpa, Antonio
    • The Korean Journal of Physiology and Pharmacology
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    • v.3 no.1
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    • pp.59-68
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    • 1999
  • Chemically induced hypoxia has been shown to induce a depletion of ATP. Since intracellular free $Mg^{2+}\;([Mg^{2+}]_i)$ appears to be tightly regulated following cellular energy depletion, we hypothesized that the increase in $[Mg^{2+}]_i$ would result in $Mg^{2+}$ extrusion following hormonal stimulation. To determine the relation between $Mg^{2+}$ efflux and cellular energy state in a hypoxic rat heart and isolated myocytes, $[Mg^{2+}]_i,$ ATP and $Mg^{2+}$ content were measured by using mag-fura-2, luciferin-luciferase and atomic absorbance spectrophotometry. $Mg^{2+}$ effluxes were stimulated by norepinephrine (NE) or cAMP analogues, respectively. $Mg^{2+}$ effluxes induced by NE or cAMP were more stimulated in the presence of metabolic inhibitors (MI). Chemical hypoxia with NaCN (2 mM) caused a rapid decrease of cellular ATP within 1 min. Measurement of $[Mg^{2+}]_i$ confirmed that ATP depletion was accompanied by an increase in $[Mg^{2+}]_i.$ No change in $Mg^{2+}$ efflux was observed when cells were incubated with MI. In the presence of MI, the cAMP-induced $Mg^{2+}$ effluxes were inhibited by quinidine, imipramine, and removal of extracellular $Na^+.$ In addition, after several min of perfusion with $Na^+-free$ buffer, a large increase in $Mg^{2+}$ efflux occurred when $Na^+-free$ buffer was switched to 120 mM $Na^+$ containing buffer. A similar $Mg^{2+}$ efflux was observed in myocytes. These effluxes were inhibited by quinidine and imipramine. These results indicate that the activation of $Mg^{2+}$ effluxes by hormonal stimulation is directly dependent on intracellular $Mg^{2+}$ contents and that these $Mg^{2+}$ effluxes appear to occur through the $Na^+-dependent\;Na^+/Mg^{2+}$ exchange system during chemical hypoxia.

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