Pro-Apoptotic and Immunostimulatory Tetrahydroxanthone Dimers from the Endophytic Fungus Phomopsis longicolla

Ro&#x308,nsberg, David,Debbab, Abdessamad,Má,ndi, Attila,Vasylyeva, Vera,Bo&#x308,hler, Philip,Stork, Bjo&#x308,rn,Engelke, Laura,Hamacher, Alexandra,Sawadogo, Richard,Diederich, Marc,Wray, Vict American Chemical Society 2013 Journal of organic chemistry Vol.78 No.24

<P>Four tetrahydroxanthone dimers (<B>1</B>–<B>4</B>) and four biogenetically related monomers (<B>5</B>–<B>8</B>), including the new derivatives <B>4</B>–<B>6</B>, were isolated from the endophyte Phomopsis longicolla. The absolute configurations of <B>2</B>–<B>4</B> were established for the first time by TDDFT electronic circular dichroism calculations, and that of phomoxanthone A (<B>1</B>) was revised by X-ray crystallography. Phomoxanthone A (<B>1</B>) showed the strongest pro-apoptotic activity when tested against a panel of human cancer cell lines, including cisplatin-resistant cells, whereas it was up to 100-fold less active against healthy blood cells. It was also the most potent activator of murine T lymphocytes, NK cells, and macrophages, suggesting an activation of the immune system in parallel to its pro-apoptotic activity. This dual effect in combating cancer cells could help in fighting resistance during chemotherapy. Preliminary structure–activity studies of isolated compounds and derivatives obtained by semisynthesis (<B>9a</B>–<B>11</B>) hinted at the location of the biaryl axis and the presence of acetyl groups as important structural elements for the biological activity of the studied tetrahydroxanthones.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/joceah/2013/joceah.2013.78.issue-24/jo402066b/production/images/medium/jo-2013-02066b_0011.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jo402066b'>ACS Electronic Supporting Info</A></P>

Nanoplasmonic Ruler for Measuring Separation Distance between Supported Lipid Bilayers and Oxide Surfaces

Ferhan, Abdul Rahim,S&#x30c,pac&#x30c,kova&#x301,, Barbora,Jackman, Joshua A.,Ma, Gamaliel J.,Sut, Tun Naw,Homola, Jir&#x30c,i&#x301,Cho, Nam-Joon American Chemical Society 2018 ANALYTICAL CHEMISTRY - Vol.90 No.21

<P>Unraveling the details of how supported lipid bilayers (SLBs) are coupled to oxide surfaces is experimentally challenging, and there is an outstanding need to develop highly surface-sensitive measurement strategies to determine SLB separation distances. Indeed, subtle variations in separation distance can be associated with significant differences in bilayer-substrate interaction energy. Herein, we report a nanoplasmonic ruler strategy to measure the absolute separation distance between SLBs and oxide surfaces. A localized surface plasmon resonance (LSPR) sensor was employed to track SLB formation onto titania- and silica-coated gold nanodisk arrays. To interpret measurement data, an analytical model relating the LSPR measurement response to bilayer-substrate separation distance was developed based on finite-difference time-domain (FDTD) simulations and theoretical calculations. The results indicate that there is a larger separation distance between SLBs and titania surfaces than silica surfaces, and the trend was consistent across three tested lipid compositions. We discuss these findings within the context of the interfacial forces underpinning bilayer-substrate interactions, and the nanoplasmonic ruler strategy provides the first direct experimental evidence comparing SLB separation distances on titania and silica surfaces.</P> [FIG OMISSION]</BR>

Reconstruction and evolutionary history of eutherian chromosomes

Kim, Jaebum,Farre&#x301,, Marta,Auvil, Loretta,Capitanu, Boris,Larkin, Denis M.,Ma, Jian,Lewin, Harris A. National Academy of Sciences 2017 Proceedings of the National Academy of Sciences Vol.114 No.27

<P>Whole-genome assemblies of 19 placental mammals and two outgroup species were used to reconstruct the order and orientation of syntenic fragments in chromosomes of the eutherian ancestor and six other descendant ancestors leading to human. For ancestral chromosome reconstructions, we developed an algorithm (DESCHRAMBLER) that probabilistically determines the adjacencies of syntenic fragments using chromosome-scale and fragmented genome assemblies. The reconstructed chromosomes of the eutherian, boreoeutherian, and euarchontoglires ancestor each included >80% of the entire length of the human genome, whereas reconstructed chromosomes of the most recent common ancestor of simians, catarrhini, great apes, and humans and chimpanzees included >90% of human genome sequence. These high-coverage reconstructions permitted reliable identification of chromosomal rearrangements over similar to 105 My of eutherian evolution. Orangutan was found to have eight chromosomes that were completely conserved in homologous sequence order and orientation with the eutherian ancestor, the largest number for any species. Ruminant artiodactyls had the highest frequency of intrachromosomal rearrangements, and interchromosomal rearrangements dominated in murid rodents. A total of 162 chromosomal breakpoints in evolution of the eutherian ancestral genome to the human genome were identified; however, the rate of rearrangements was significantly lower (0.80/My) during the first similar to 60 My of eutherian evolution, then increased to greater than 2.0/My along the five primate lineages studied. Our results significantly expand knowledge of eutherian genome evolution and will facilitate greater understanding of the role of chromosome rearrangements in adaptation, speciation, and the etiology of inherited and spontaneously occurring diseases.</P>

Corticotropin Releasing Hormone and Urocortin 3 Stimulate Vascular Endothelial Growth Factor Expression through the cAMP/CREB Pathway

Rhee, Sang Hoon,Ma, Elise L.,Lee, Yunna,Tache&#x301,, Yvette,Pothoulakis, Charalabos,Im, Eunok American Society for Biochemistry and Molecular Bi 2015 The Journal of biological chemistry Vol.290 No.43

<P>Colonic epithelium is the first line of defense against various pathological offenses in the gut. Previous studies have shown that the peptides of the corticotropin-releasing hormone (CRH) family modulate vascular endothelial growth factor (VEGF)-A production in other cells. Here we sought to investigate whether CRH and urocortin (Ucn) 3 regulate VEGF-A secretion in colonocytes through CRH receptors and to elucidate the underlying mechanism of action. CRH and Ucn 3 significantly increased the expression levels of VEGF-A mRNA and protein through CRH receptor 1 and 2, respectively, in human colonic epithelial cells and primary mouse intestinal epithelial cells. Underlying mechanisms involve activation of adenylyl cyclase with subsequent increase of intracellular cAMP level and increased DNA binding activity of transcription factor CREB on VEGF-A promoter region. Finally, genetic deficiency of CREB decreased intestinal inflammation and VEGF-A expression in a dextran sodium sulfate-induced colitis model. These results show that activation of CRH receptors by CRH ligands stimulates VEGF-A expression in intestinal epithelial cells through the cAMP/CREB pathway. Since VEGF-A boosts inflammatory responses through angiogenesis, these data suggest that CREB may be a key effector of CRH and Ucn 3-dependent inflammatory angiogenesis.</P>

A Reel-Wound Carbon Nanotube Polarizer for Terahertz Frequencies

Kyoung, Jisoo,Jang, Eui Yun,Lima, Má,rcio D.,Park, Hyeong-Ryeol,Robles, Raquel Ovalle,Lepro&#x301,, Xavier,Kim, Yong Hyup,Baughman, Ray H.,Kim, Dai-Sik American Chemical Society 2011 NANO LETTERS Vol.11 No.10

<P>Utilizing highly oriented multiwalled carbon nanotube aerogel sheets, we fabricated micrometer-thick freestanding carbon nanotube (CNT) polarizers. Simple winding of nanotube sheets on a U-shaped polyethylene reel enabled rapid and reliable polarizer fabrication, bypassing lithography or chemical etching processes. With the remarkable extinction ratio reaching ∼37 dB in the broad spectral range from 0.1 to 2.0 THz, combined with the extraordinary gravimetric mechanical strength of CNTs, and the dispersionless character of freestanding sheets, the commercialization prospects for our CNT terahertz polarizers appear attractive.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2011/nalefd.2011.11.issue-10/nl202214y/production/images/medium/nl-2011-02214y_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl202214y'>ACS Electronic Supporting Info</A></P>

Enhanced Multiple Exciton Generation in PbS|CdS Janus-like Heterostructured Nanocrystals

Kroupa, Daniel M.,Pach, Gregory F.,Vo&#x308,ro&#x308,s, Má,rton,Giberti, Federico,Chernomordik, Boris D.,Crisp, Ryan W.,Nozik, Arthur J.,Johnson, Justin C.,Singh, Rohan,Klimov, Victor I.,Galli, American Chemical Society 2018 ACS NANO Vol.12 No.10

<P>Generating multiple excitons by a single high-energy photon is a promising third-generation solar energy conversion strategy. We demonstrate that multiple exciton generation (MEG) in PbS|CdS Janus-like heteronanostructures is enhanced over that of single-component and core/shell nanocrystal architectures, with an onset close to two times the PbS band gap. We attribute the enhanced MEG to the asymmetric nature of the heteronanostructure that results in an increase in the effective Coulomb interaction that drives MEG and a reduction of the competing hot exciton cooling rate. Slowed cooling occurs through effective trapping of hot-holes by a manifold of valence band interfacial states having both PbS and CdS character, as evidenced by photoluminescence studies and <I>ab initio</I> calculations. Using transient photocurrent spectroscopy, we find that the MEG characteristics of the individual nanostructures are maintained in conductive arrays and demonstrate that these quasi-spherical PbS|CdS nanocrystals can be incorporated as the main absorber layer in functional solid-state solar cell architectures. Finally, based upon our analysis, we provide design rules for the next generation of engineered nanocrystals to further improve the MEG characteristics.</P> [FIG OMISSION]</BR>

All-Solid-State Carbon Nanotube Torsional and Tensile Artificial Muscles

Lee, Jae Ah,Kim, Youn Tae,Spinks, Geoffrey M.,Suh, Dongseok,Lepro&#x301,, Xavier,Lima, Má,cio D.,Baughman, Ray H.,Kim, Seon Jeong American Chemical Society 2014 NANO LETTERS Vol.14 No.5

<P>We report electrochemically powered, all-solid-state torsional and tensile artificial yarn muscles using a spinnable carbon nanotube (CNT) sheet that provides attractive performance. Large torsional muscle stroke (53°/mm) with minor hysteresis loop was obtained for a low applied voltage (5 V) without the use of a relatively complex three-electrode electromechanical setup, liquid electrolyte, or packaging. Useful tensile muscle strokes were obtained (1.3% at 2.5 V and 0.52% at 1 V) when lifting loads that are ∼25 times heavier than can be lifted by the same diameter human skeletal muscle. Also, the tensile actuator maintained its contraction following charging and subsequent disconnection from the power supply because of its own supercapacitor property at the same time. Possible eventual applications for the individual tensile and torsional muscles are in micromechanical devices, such as for controlling valves and stirring liquids in microfluidic circuits, and in medical catheters.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2014/nalefd.2014.14.issue-5/nl500526r/production/images/medium/nl-2014-00526r_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl500526r'>ACS Electronic Supporting Info</A></P>

Ultrastretchable Analog/Digital Signal Transmission Line with Carbon Nanotube Sheets

Lee, Yourack,Joo, Min-Kyu,Le, Viet Thong,Ovalle-Robles, Raquel,Lepro&#x301,, Xavier,Lima, Má,rcio D.,Suh, Daniel G.,Yu, Han Young,Lee, Young Hee,Suh, Dongseok American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.31

<P>Stretchable conductors can be used in various applications depending on their own characteristics. Here, we demonstrate simple and robust elastomeric conductors that are optimized for stretchable electrical signal transmission line. They can withstand strains up to 600% without any substantial change in their resistance (<= 10% as is and <= 1% with passivation), and exhibit suppressed charge fluctuations in the medium. The inherent elasticity of a polymeric rubber and the high conductivity of flexible, highly oriented carbon nanotube sheets were combined synergistically, without losing both properties. The nanoscopic strong adhesion between aligned carbon nanotube arrays and strained elastomeric polymers induces conductive wavy folds with microscopic bending of radii on the scale of a few micrometers. Such features enable practical applications such as in elastomeric length-changeable electrical digital and analog signal transmission lines at above MHz frequencies. In addition to reporting basic direct current, alternating current, and noise characterizations of the elastomeric conductors, various examples as a stretchable signal transmission line up to 600% strains are presented by confirming the capability of transmitting audio and video signals, as well as low-frequency medical signals without information distortion.</P>

International Comparison of Enumeration-Based Quantification of DNA Copy-Concentration Using Flow Cytometric Counting and Digital Polymerase Chain Reaction

Yoo, Hee-Bong,Park, Sang-Ryoul,Dong, Lianhua,Wang, Jing,Sui, Zhiwei,Pavs&#x30c,ic&#x30c,, Jernej,Milavec, Mojca,Akgoz, Muslum,Moziog&#x306,lu, Erkan,Corbisier, Philippe,Janka, Má,trai,Cosme, Bru American Chemical Society 2016 ANALYTICAL CHEMISTRY - Vol.88 No.24

<P>Enumeration-based determination of DNA copy-concentration was assessed through an international comparison among national metrology institutes (NMIs) and designated institutes (DIs). Enumeration-based quantification does not require a calibration standard thereby providing a route to 'absolute quantification', which offers the potential for reliable value assignments of DNA reference materials, and International System of Units (SI) traceability to copy number 1 through accurate counting. In this study, 2 enumeration based methods, flow cytometric (FCM) counting and the digital polymerase chain reaction (dPCR), were compared to quantify a solution of the pBR322 plasmid at a concentration of several thousand copies per microliter. In addition, 2 orthogonal chemical-analysis methods based on nucleotide quantification, isotope-dilution mass spectrometry (IDMS) and capillary electrophoresis (CE) were applied to quantify a more concentrated solution of the plasmid. Although 9 dPCR results from 8 laboratories showed some dispersion (relative standard deviation [RSD] = 11.8%), their means were closely aligned with those of the FCM-based counting method and the orthogonal chemical-analysis methods, corrected for gravimetric dilution factors. Using the means of dPCR results, the RSD of all 4 methods was 1.8%, which strongly supported the validity of the recent enumeration approaches. Despite a good overall agreement, the individual dPCR results were not sufficiently covered by the reported measurement uncertainties. These findings suggest that some laboratories may not have considered all factors contributing to the measurement uncertainty of dPCR, and further investigation of this possibility is warranted.</P>

Hybrid Nanomembranes for High Power and High Energy Density Supercapacitors and Their Yarn Application

Lee, Jae Ah,Shin, Min Kyoon,Kim, Shi Hyeong,Kim, Seon Jeong,Spinks, Geoffrey M.,Wallace, Gordon G.,Ovalle-Robles, Raquel,Lima, Má,rcio D.,Kozlov, Mikhail E.,Baughman, Ray H. American Chemical Society 2012 ACS NANO Vol.6 No.1

<P>We report mechanically robust, electrically conductive, free-standing, and transparent hybrid nanomembranes made of densified carbon nanotube sheets that were coated with poly(3,4-ethylenedioxythiophene) using vapor phase polymerization and their performance as supercapacitors. The hybrid nanomembranes with thickness of ∼66 nm and low areal density of ∼15 μg/cm<SUP>2</SUP>exhibited high mechanical strength and modulus of 135 MPa and 12.6 GPa, respectively. They also had remarkable shape recovery ability in liquid and at the liquid/air interface unlike previous carbon nanotube sheets. The hybrid nanomembrane attached on a current collector had volumetric capacitance of ∼40 F/cm<SUP>3</SUP> at 100 V s<SUP>–1</SUP> (∼40 and ∼80 times larger than that of onion-like carbon measured at 100 V s<SUP>–1</SUP> and activated carbon measured at 20 V s<SUP>–1</SUP>, respectively), and it showed rectangular shapes of cyclic voltammograms up to ∼5 V s<SUP>–1</SUP>. High mechanical strength and flexibility of the hybrid nanomembrane enabled twisting it into microsupercapacitor yarns with diameters of ∼30 μm. The yarn supercapacitor showed stable cycling performance without a metal current collector, and its capacitance decrease was only ∼6% after 5000 cycles. Volumetric energy and power density of the hybrid nanomembrane was ∼70 mWh cm<SUP>–3</SUP> and ∼7910 W cm<SUP>–3</SUP>, and the yarn possessed the energy and power density of ∼47 mWh cm<SUP>–3</SUP> and ∼538 W cm<SUP>–3</SUP>.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2012/ancac3.2012.6.issue-1/nn203640a/production/images/medium/nn-2011-03640a_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn203640a'>ACS Electronic Supporting Info</A></P>