Seasonal carbon uptake rates of phytoplankton in the northern East/Japan Sea

Lee, S.H.,Joo, H.,Lee, J.H.,Lee, J.H.,Kang, J.J.,Lee, H.W.,Lee, D.,Kang, C.K. Pergamon Press 2017 Deep-sea research. Part II, Topical studies in oce Vol.143 No.-

Korea-Russia joint expeditions have been conducted mainly in the less studied Russian sector of the East/Japan Sea to understand the physical and ecological structures. In this study, the carbon uptake rates of phytoplankton measured in 2012 (middle-late October) and 2015 (middle April-early May) were analyzed to understand seasonal and spatial distributions of phytoplankton production, using a <SUP>13</SUP>C-<SUP>15</SUP>N dual isotope tracer technique. The water columns in the euphotic layers were well mixed during our cruise periods in both years. The water column-integrated chl-a concentrations (mean +/- S.D. = 2.28 +/- 1.47mgm<SUP>-3</SUP>) in 2015 was significantly higher (t-test, p < 0.01) than in 2012 (mean +/- S.D. = 0.49 +/- 0.29mgm<SUP>-3</SUP>) because of different sampling seasons. Small phytoplankton (< 2 μm) were relatively dominant in 2012, whereas different sizes of phytoplankton were evenly distributed in 2015 although a spatial distribution of large phytoplankton (> 20 μm) was observed near the Russian coast. The daily carbon uptake rates in this study were 180.5 and 441.6mgC m<SUP>-2</SUP> d<SUP>-1</SUP> in 2012 and 2015, respectively which are significantly (t-test, p < 0.01) lower than the averaged values previously reported in the East/Japan Sea (863 +/- 679.6mgC m<SUP>-2</SUP> d<SUP>-1</SUP>). The potential reasons for the lower rate in this study are discussed. The small phytoplankton contribution (47.4%) averaged from the two different cruises in this study is consistent with the result (47%) reported in temperate regions. Moreover, a significantly (t-test, p < 0.01) lower contribution of small phytoplankton in total primary production than total phytoplankton biomass in this study is consistent with the results from other regions. Lower total primary production might be expected due to increasing contribution of small phytoplankton under warmer conditions.

J-PLUS: Identification of low-metallicity stars with artificial neural networks using SPHINX

Whitten, D. D.,Placco, V. M.,Beers, T. C.,Chies-Santos, A. L.,Bonatto, C.,Varela, J.,Cristó,bal-Hornillos, D.,Ederoclite, A.,Masseron, T.,Lee, Y. S.,Akras, S.,Borges Fernandes, M.,Caballero, J. Springer-Verlag 2019 Astronomy and astrophysics Vol.622 No.-

<P><I>Context.</I> We present a new methodology for the estimation of stellar atmospheric parameters from narrow- and intermediate-band photometry of the Javalambre Photometric Local Universe Survey (J-PLUS), and propose a method for target pre-selection of low-metallicity stars for follow-up spectroscopic studies. Photometric metallicity estimates for stars in the globular cluster M15 are determined using this method.</P><P><I>Aims.</I> By development of a neural-network-based photometry pipeline, we aim to produce estimates of effective temperature, <I>T</I>eff, and metallicity, [Fe/H], for a large subset of stars in the J-PLUS footprint.</P><P><I>Methods.</I> The Stellar Photometric Index Network Explorer, SPHINX, was developed to produce estimates of <I>T</I>eff and [Fe/H], after training on a combination of J-PLUS photometric inputs and synthetic magnitudes computed for medium-resolution (<I>R</I> ~ 2000) spectra of the Sloan Digital Sky Survey. This methodology was applied to J-PLUS photometry of the globular cluster M15.</P><P><I>Results.</I> Effective temperature estimates made with J-PLUS Early Data Release photometry exhibit low scatter, σ(<I>T</I>eff) = 91 K, over the temperature range 4500 < <I>T</I>eff (K) < 8500. For stars from the J-PLUS First Data Release with 4500 < <I>T</I>eff (K) < 6200, 85 ± 3% of stars known to have [Fe/H] < −2.0 are recovered by SPHINX. A mean metallicity of [Fe/H] = − 2.32 ± 0.01, with a residual spread of 0.3 dex, is determined for M15 using J-PLUS photometry of 664 likely cluster members.</P><P><I>Conclusions.</I> We confirm the performance of SPHINX within the ranges specified, and verify its utility as a stand-alone tool for photometric estimation of effective temperature and metallicity, and for pre-selection of metal-poor spectroscopic targets.</P>

Structural insights into conserved l-arabinose metabolic enzymes reveal the substrate binding site of a thermophilic l-arabinose isomerase

Lee, Y.J.,Lee, S.J.,Kim, S.B.,Lee, S.J.,Lee, S.H.,Lee, D.W. North-Holland Pub ; Elsevier Science Ltd 2014 FEBS letters Vol.588 No.6

Structural genomics demonstrates that despite low levels of structural similarity of proteins comprising a metabolic pathway, their substrate binding regions are likely to be conserved. Herein based on the 3D-structures of the α/β-fold proteins involved in the ara operon, we attempted to predict the substrate binding residues of thermophilic Geobacillus stearothermophilusl-arabinose isomerase (GSAI) with no 3D-structure available. Comparison of the structures of l-arabinose catabolic enzymes revealed a conserved feature to form the substrate-binding modules, which can be extended to predict the substrate binding site of GSAI (i.e., D195, E261 and E333). Moreover, these data implicated that proteins in the l-arabinose metabolic pathway might retain their substrate binding niches as the modular structure through conserved molecular evolution even with totally different structural scaffolds.

Clinical outcomes of venous thromboembolism with dalteparin therapy in multiple myeloma patients

Lee, S.E.,Jeon, Y.W.,Yoon, J.H.,Cho, B.S.,Eom, K.S.,Kim, Y.J.,Kim, H.J.,Lee, S.,Cho, S.G.,Kim, D.W.,Lee, J.W.,Min, W.S.,Kim, M.,Min, C.K. Pergamon Press 2015 Thrombosis research Vol.136 No.5

This study focused on the clinical outcomes in multiple myeloma (MM) patients with venous thromboembolism (VTE) who received low-molecular-weight heparin (dalteparin) therapy. Changes in D-dimer levels before and after VTE were also evaluated. Among 549 patients treated with various chemotherapeutic agents, a total of 52 (9.47%) patients including 32 newly diagnosed with MM and 16 with relapsed/refractory MM developed VTE, 48 of whom received dalteparin. Among the 48 treated patients, 37 (77%) had proximal deep vein thrombosis (DVT), four had (8%) pulmonary embolism (PE), and seven (15%) had both DVT and PE. In 32 patients with available paired samples (at baseline and VTE occurrence), significant conversion of D-dimer levels from 2.2+/-0.4mg/L to 11.8+/-1.6mg/L (P<0.001) was observed, which decreased from 10.9+/-0.4mg/L to 1.9+/-0.6mg/L one month after initiating dalteparin therapy. A total of 44 patients received dalteparin with a median duration of 4.2months (range, 2.7-9.4), and four patients were discontinued early due to death (n=3) and major bleeding (n=1). After a median follow-up of 9.0months (range, 0.7-35.8) since the first VTE episode, five patients showed recurrence of VTE with a cumulative incidence of 17.5+/-7.9%. Major bleeding occurred in three patients. In summary, dalteparin seems to be a promising drug for the treatment of VTE in MM. In addition, the significant difference in D-dimer levels observed before occurrence of VTE and after dalteparin treatment may suggest the usefulness of D-dimer testing as a surrogate marker for VTE in MM patients.

Thermodynamic behaviors of excitonic emission in ZnO nanorods grown by pulsed laser deposition

Lee, Y.,Lee, D.J.,Cho, H.D.,Yoon, I.T.,Shon, Y.,Lee, S. North-Holland 2017 Journal of luminescence Vol.190 No.-

We investigated the thermodynamic behaviors of the exciton emission in ZnO nanorods that had been grown by laser ablation. The ZnO nanorods exhibited a clear luminescence peak from the neutral donor-bound exciton (D<SUP>0</SUP>X), which persisted near room temperature. Through analyzing temperature-dependences of photoluminescence properties, we found out insignificant thermal-quenching of D<SUP>0</SUP>X, arising from the large donor binding energy (i.e., E<SUB>bD(NR)</SUB> ~ 51.1 +/- 7.3meV). A small discrepancy of E<SUB>bD(NR)</SUB> from ZnO bulks' values (i.e., E<SUB>bD(Bulk)</SUB> = 53 - 72meV) is associated with inhomogeneous thermal-broadening factors such as defect-scattering at the surface of the nanorod. Despite of inhomogeneous thermal-broadening, the ZnO nanorods still have a high luminescence efficiency because of the weak homogeneous thermal-broadening effect (i.e., low exciton-phonon coupling).

Probiotic properties of Pediococcus strains isolated from jeotgals, salted and fermented Korean sea-food

Lee, K.W.,Park, J.Y.,Sa, H.D.,Jeong, J.H.,Jin, D.E.,Heo, H.J.,Kim, J.H. Academic Press 2014 Anaerobe Vol.28 No.-

Three Pediococcus pentosaceus strains were isolated from jeotgals, salted and fermented Korean sea-foods, and their probiotic potentials were examined. After 2 h exposure to pH 3.0, P. pentosaceus F66 survived with the survival ratio of 32.6% followed by P. pentosaceus D56 (17.2%) and P. pentosaceus A24 (7.5%). P. pentosaceus F66 also survived better (26.6%) than P. pentosaceus A24 (13.7%) and P. pentosaceus D56 (5.8%) after 2 h exposure to 0.3% bile salts. Three strains grew slowly on MRS broth with 15% NaCl (w/v), reaching the OD<SUB>600</SUB> values of 0.4-0.8 in 36 h. They adhered to Caco-2 cells (10.9-13.9 CFU/cell) with similar degree of adherence of a positive control, Lactobacillus rhamnosus GG (12.8 +/- 0.5 CFU/cell). Three strains possess some desirable enzyme activities such as β-galactosidase, α-glucosidase, β-glucosidase, and N-acetyl-β-glucosidase. From these results, P. pentosaceus F66 seems qualified as a probiotic and can be utilized for fermented foods including jeotgals.

급성 D. D. S. 중독증의 임상적 고찰

정시전 ( S. J. Chung ),최등영 ( D. Y. Choi ),이천각 ( C. K. Lee ),김형순 ( H. S. Kim ),태철현 ( T. H. Jeen ) 대한내과학회 1968 대한내과학회지 Vol.11 No.4

D.D.S. is well known as the drug of choice for Leprosy. Chronic D.D.S. intoxication has been reported in the many countries. It includes hematological changes, skin manifestations, abnormal liver function test and psychosis, There are few acute intoxicatio

Ahnak functions as a tumor suppressor via modulation of TGFβ/Smad signaling pathway

Lee, I H,Sohn, M,Lim, H J,Yoon, S,Oh, H,Shin, S,Shin, J H,Oh, S-H,Kim, J,Lee, D K,Noh, D Y,Bae, D S,Seong, J K,Bae, Y S Macmillan Publishers Limited 2014 Oncogene Vol.33 No.38

We provide detailed mechanisms of Ahnak-mediated potentiation of transforming growth factor β (TGFβ) signaling, which leads to a negative regulation of cell growth. We show that Smad3 interacts with Ahnak through MH2 domain and that Ahnak stimulates Smad3 localization into nucleus leading to potentiating TGFβ-induced transcriptional activity of R-Smad. Moreover, overexpression of Ahnak resulted in growth retardation and cell cycle arrest through downregulation of c-Myc and cyclin D1/D2. We describe results from analyses of Ahnak<SUP>−/−</SUP> mouse model expressing middle T antigen in a mammary gland-specific manner (MMTV<SUP>Tg/+</SUP>Ahnak<SUP>−/−</SUP>), which showed significantly progressed hyperplasia of mammary glands compared with MMTV<SUP>Tg/+</SUP>Ahnak<SUP>+/+</SUP>. Finally, we screened multiple human breast cancer tissues and showed that the expression of Ahnak in cancer tissues is lower than that in control tissues by 50%. Taken together, these data indicate that Ahnak mediates a negative regulation of cell growth and acts as novel tumor suppressor through potentiation of TGFβ signaling.

miR-302b maintains ''stemness'' of human embryonal carcinoma cells by post-transcriptional regulation of Cyclin D2 expression

Lee, N.S.,Kim, J.S.,Cho, W.J.,Lee, M.R.,Steiner, R.,Gompers, A.,Ling, D.,Zhang, J.,Strom, P.,Behlke, M.,Moon, S.H.,Salvaterra, P.M.,Jove, R.,Kim, K.S. Academic Press 2008 Biochemical and biophysical research communication Vol.377 No.2

Embryonic stem cells (ESCs) and embryonal carcinoma cells (ECCs) possess the remarkable property of self-renewal and differentiation potency. They are model preparations for investigating the underlying mechanisms of ''stemness''. microRNAs are recently discovered small noncoding RNAs with a broad spectrum of functions, especially in control of development. Here, we show that miR-302b indirectly regulates expression of the pluripotent stem cell marker Oct4, and it directly regulates expression of Cyclin D2 protein, a developmental regulator during gastrulation. Using loss-of function and gain-of function approaches, we demonstrate that functional miR-302b is necessary to maintain stem cell self-renewal and inhibit neuronal differentiation of human ECCs. During retinoic acid-induced neuronal differentiation, Cyclin D2 protein but not mRNA expression is strongly increased, concurrent with the down-regulation of miR-302b and Oct4. Our results suggest that miR-302b plays an important role in maintaining the pluripotency of ECCs and probably ESCs, by post-transcriptional regulation of Cyclin D2 expression.

Crystal structures of LacD from Staphylococcus aureus and LacD.1 from Streptococcus pyogenes: Insights into substrate specificity and virulence gene regulation

Lee, S.J.,Kim, H.S.,Kim, D.J.,Yoon, H.J.,Kim, K.H.,Yoon, J.Y.,Suh, S.W. North-Holland Pub ; Elsevier Science Ltd 2011 FEBS letters Vol.585 No.2

Staphylococcus aureus LacD, a Class I tagatose-1,6-bisphosphate (TBP) aldolase, shows broadened substrate specificity by catalyzing the cleavage of 1,6-bisphosphate derivatives of d-tagatose, d-fructose, d-sorbose, and d-psicose. LacD.1 and LacD.2 are two closely-related Class I TBP aldolases in Streptococcus pyogenes. Here we have determined the crystal structures of S. aureus LacD and S. pyogenes LacD.1. Monomers of both enzymes are folded into a (β/α)<SUB>8</SUB> barrel and two monomers associate tightly to form a dimer in the crystals. The structures suggest that the residues E189 and S300 of rabbit muscle Class I fructose-1,6-bisphosphate (FBP) aldolase are important for substrate specificity. When we mutated the corresponding residues of S. aureus LacD, the mutants (L165E, L275S, and L165E/L275S) showed enhanced substrate specificity toward FBP. Structured summary: lacDbinds to lacD by X-ray crystallography(View interaction) lacD1binds to lacD1 by X-ray crystallography(View interaction)