Synthesis of (–)-Muricatacin

The synthesis of (–)-muricatacin starting from 1-bromododecane and 2-pentyn-l-ol is described. 2-Pentadecyn-1-ol (4), which was prepared from 1-bromododecane (2) and 2-pentyn-1-ol (3), was converted to epoxy alcohol 6 through a two-step reaction sequence, 6 being successively submitted to tosylation, iodination, chain extension with tert-butyl lithioacetate, and acid-catalyzed cyclization to give (–)-muricatacin (1a). Recrystallization afforded optically pure 1a.     

Timeline of Genomics (1901–1950)

Year Event and Theoretical Implication/Extension1901 Hugo de Vries adopts the term MUTATION to describe sudden, spontaneous, drastic alterations in the hereditary material of Oenothera. Thomas Harrison Montgomery studies sper- matogenesis in various species of Hemiptera and ?nds that maternal chromosomes only pair with paternal chromosomes during meiosis. Clarence Ervin McClung postulates that the so- called accessory chromosome (now known as the “X” chromosome) is male determining.…     

Timeline of Genomics (1951–1976)

Year Event and Theoretical Implication/Extension Reference1951 Esther M. Lederberg discovers bacteriophage Lederberg, E.M. 1951. Lysogenicity in E. lambda, the ?rst viral episome of E. coli. coli K12. Genetics 36: 560.1952 Alfred Day Hershey (1969 Noble Prize Laureate Hershey, A.D. and Chase, M. 1952. In- for Physiology or Medicine) and Martha Chase dependent functions of viral protein and perform an experiment by using T2 bacteriophage nucleic acid in growth of bacteriophage. that…     

Microbial functionalization of (–)-ambroxide by filamentous fungi

Abstract

Biocatalysis is a very useful tool for organic chemists to functionalize organic compounds under working conditions milder than chemical ones. This methodology has special significance since it can be an easy way to introduce a functional group in a non-reactive carbon, regio- and stereoselectively. In order to look for new compounds with antioxidant activity we report the transformation of the natural substrate (–)-ambroxide using the enzyme potential of pure strains of the filamentous fungi Alternaria alternata and Cunninghamella sp., following a protocol with growing cell cultures, which produced the new compound 1β-hydroxyambroxide and the previously known compound 3β-hydroxyambroxide. After purification their structures were elucidated by spectroscopic methods. These two metabolites are the products of oxidation of ring A of the starting material, without evidence of other compounds with different functionalization. Both compounds were tested for their activity as free radical scavengers in vitro, using the assay of DPPH (1,1-diphenyl-2-picrylhydrazyl) radical trapping. The results demonstrated that hydroxylation of carbons C-1 and C-3 of (–)-ambroxide with β stereochemistry had no effect on biological activity as an antioxidant compared with the starting material and a reference substance.     

Publications of Anthony Calhoun Clement (1909–1984)

Summary

Two zoeae and the megalopa of the majid crab Macropodia parva were obtained from laboratory material. At 25±1°C and 35% salinity, the first crab appeared 12 days after hatching; survival to the first crab instar was 27%. The larval stages are described in detail and compared with those of the previously described species of the genus Macropodia. Zoeal characteristics of M. parva that differentiate it from other known Macropodia larvae are the naked telson furcae and the absence, in zoea II, of the exopodal setae on the basis of the maxillule.     

Genetic Aspects of Myoclonus–Dystonia Syndrome (MDS)

Myoclonus–dystonia (M–D) is an autosomal-dominant movement disorder with onset in the first two decades of life. Mutations in the epsilon-sarcoglycan gene (SGCE, DYT11) on chromosome 7q21–q31 represent the major genetic cause of M–D in some populations. The syndrome was related with mutations in two other genes (DRD2 and DYT1). A second locus has been reported in one large M–D family (DYT15, 18p11), but no gene has been identified yet. In this review, we discuss genetic aspects of myoclonus–dystonia.     

First occurrence of Palaeotheriidae (Perissodactyla) from the late–middle Eocene of eastern Thrace (Greece)

A detailed assessment of postcranial fossils collected at Balouk Keui (Thrace, Greece) in the mid-19th Century by the naturalist Auguste Viquesnel enabled us to identify the material as pertaining to Palaeotherium sp., cf. P. magnum, which constitutes the easternmost occurrence of the genus during the Eocene. We have constrained the geographic and stratigraphic provenance of the fossil by reassessing information about Viquesnel's itinerary and observations. Although the exact age of the fossil remains uncertain, the occurrence of a palaeothere in the Thrace Basin during the Eocene indicates a wider geographic distribution for the genus, which had previously been restricted to western and central Europe. The palaeothere of Balouk Keui confirms that the palaeogeographic range of this group included the Balkans during the middle–late Eocene. This discovery also shows that at least intermittent land connections between western Europe, Southeast Asia, and perhaps Central Iran facilitated mammalian dispersal during the middle–late Eocene, before the famous Grande Coupure.     

Solvation structure of sodium chloride (Na+–Cl-) ion pair in acetonitrile (AN)–dimethyl formamide (DMF) mixtures

Solvation structures of Na⁺–Cl^? ion pair are investigated in acetonitrile (AN)–dimethylformamide (DMF) isodielectric mixtures. The potentials of mean force of Na⁺–Cl^? in the five compositions of mixtures show minima corresponding to a contact ion pair (CIP) and a solvent-shared ion pair (SShIP). The solvent-separated ion pair minima are present in lower mole fractions of AN (x_AN ≤ 0.50). CIPs are found to be more stable than the SShIPs. From a thermodynamic decomposition of the potentials of mean force, we find that the formation of the ion pair is entropically driven in these compositions. The most stable CIP is in pure AN. The local solvation structures around the ion pair are analysed through the running coordination numbers, excess coordination numbers, solvent orientational distributions and density profiles. We find that both Na⁺ and Cl^? are preferentially solvated by DMF.     

In memory of Thomas Turpin Bannister (1930–2018)

Plants grown in the field experience sharp changes in irradiation due to shading effects caused by clouds, other leaves, etc. The excess of absorbed light energy is dissipated by a number of mechanisms including cyclic electron transport, photorespiration, and Mehler-type reactions. This protection is essential for survival but decreases photosynthetic efficiency. All phototrophs except angiosperms harbor flavodiiron proteins (Flvs) which relieve the excess of excitation energy on the photosynthetic electron transport chain by reducing oxygen directly to water. Introduction of cyanobacterial Flv1/Flv3 in tobacco chloroplasts resulted in transgenic plants that showed similar photosynthetic performance under steady-state illumination, but displayed faster recovery of various photosynthetic parameters, including electron transport and non-photochemical quenching during dark–light transitions. They also kept the electron transport chain in a more oxidized state and enhanced the proton motive force of dark-adapted leaves. The results indicate that, by acting as electron sinks during light transitions, Flvs contribute to increase photosynthesis protection and efficiency under changing environmental conditions as those found by plants in the field.     

Review of Japanese Cenozoic (Miocene–Modern) Vertebrate Tracks

One hundred and seventy three Cenozoic vertebrate track sites from Miocene to 1600 A.D have been reported in Japan. Three ichnofaunas can be recognized: a perissodactyl and artiodactyl ichnofauna in the Miocene, an artiodactyl and proboscidean ichnofauna in the Plio-Pleistocene, and human ichnofauna from about 900–800 B.C. to about 1400–1600 A.D. Track data indicate that a predominance of large vertebrates in fluvio-lacustrine environment in lowland changed from perissodactyls to proboscidean through Miocene to Plio-Pleistocene, and ancient people then occupied lowlands instead of large animals. Pes length of proboscidean tracks revealed temporal variation, and the relationship between proboscidean body sizes and tracks was observed. The Cenozoic Japanese proboscidean trackways can be distinguished on the basis of trackway width, as narrow- and wide-gauge, but the difference between of those narrow- and wide-gauge trackways probably indicates generic level differences. The Cenozoic Japanese bird tracks can be identified as four types: ?crane (Family Gruidae?), ?heron (Family Ardeidae?), ?stork (Family Ciconiidae?), and ?shorebird tracks.     

Chemical analysis of Lake Shira water (1997–2000)

The paper presents the results of chemical analysis of Shira during summer (July-August). The chemical composition of waters in the water body was found to be fairly homogeneous horizontally. However, the concentrations of most ions increased with depth. The near-bottom layers were characterised by higher total mineral content and ash content, higher concentration of sulphates, sulphites, sulphide, phosphorus, ammonium nitrogen, as compared to the layers above. Maximum concentration of oxygen was recorded in 6–8 m stratum, where the photosynthetic processes were most active. The anaerobic layer which lay below the 12 m depth contained high concentrations of sulphide and sulphite. The composition of the lake water could be characterised as sulphate-chloride-bicarbonate sodium-magnesium. The changes in the water quality due to any anthropogenic emissions were not marked.     

In memory of Professor Biao Ding(1960–2015)

<正>It is with profound sadness that we mourn the loss of Dr.Biao Ding,a full-professor in the Department of Molecular Genetics,Ohio State University(OSU),and a world-renowned plant biologist with leading authority in viroid research.He died suddenly on June 26,2015 in Prague,Czech Republic,while attending the International Conference on Viroids and Viroid-Like RNAs as a Keynote Speaker.Dr.Ding was born in 1960,in Kunming,Yunnan Province,China.He received his B.S.from Beijing Forestry University in1982,and was then selected as one of the first group of     

In memory of Aleksandr Borisovich Devin (1944–2007)

Chronicle

In memory of Aleksandr Borisovich Devin (1944–2007)     

Biological activity of cholecystokinin (30–33) tetrapeptide analogues

Analogues of the endogenous peptide corresponding to the 30–33 sequence of cholecystokinin (Trp-Met-Asp-Phe-NH₂) were synthesized, and their biological activity was studied. It was shown that, in rats, the N-succinylated Nle² analogue of this tetrapeptide exhibits increased anxiolytic properties in the dark-light chamber test and an enhanced alcohol intake by both the control animals and the alcohol-dependent animals under the conditions of free choice. Introduction of an isopropyl residue into the C-terminal amide of the Nle² analogue resulted in the appearance of anxiogenic and antialcohol activity and the ability to increase the morphine analgesic effect in the tail-flick test on rats. The two synthesized analogues retained an affinity for cholecystokinin receptors.__________Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 2, 2005, pp. 130–139.Original Russian Text Copyright © 2005 by Proskuryakova, Bespalova, Palkeeva, Petrichenko, Pankratova, Shokhonova, Anokhina.     

In memory of Professor Ping Wu(1957–2014)

正Sadly and miserably,our beloved and respected colleague,Prof.Ping Wu,a renowned plant biologist and the vice‐president of Zhejiang University passed away in a car accident in Hangzhou,China,in the morning of June 12,2014,aged 57.Prof.Ping Wu was born on March 27,1957,in Hangzhou,Zhejiang province,received his bachelor degree in Soil Science and Agro‐chemistry in 1982 and master degree in Plant     

Computational DNA binding studies of (–)-epigallocatechin-3-gallate

The catechin family of molecules that are present in the leaves of green tea has been under investigation since the antioxidant and anti-inflammatory properties of tea were discovered. Among multiple proposed therapeutic targets of these molecules, the direct interaction with nucleic acids has been proposed and experimentally observed but without clear knowledge about the potential binding modes between these ligands and DNA. One of these catechin structures, (–)-epigallocatechin gallate (EGCG), has three aromatic rings that could interact with double-stranded DNA via terminal base-pair stacking, intercalation, or through groove binding. Using enhanced sampling techniques and molecular dynamics simulations, we have found a stable complex between the EGCG ligand and DNA through intercalation of the trihydroxybenzoate aromatic ring and an ApC step. Moreover, we have calculated the absorption spectra of four possible binding modes and compared these to absorption profiles reported in the literature, and explored the possible DNA sequence preference for the EGCG ligand to bind. Our results suggest that an intercalative mode of interaction through the major groove is possible between the EGCG ligands and DNA with apparently very little DNA sequence selectivity.