Production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from cottonseed oil and valeric acid in batch culture of Ralstonia sp. strain JC-64

A Ralstonia sp. strain JC-64 that is capable of accumulating poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P[3HB-co-3HV]) from cottonseed oil and valeric acid was isolated. By using a high limiting-nitrogen (HLN) mineral medium as the medium for the second stage of the fermentation process and by adding the two carbon sources at different times, a range of copolymers with 12–62 mol% of 3HV were produced from a series of HLN mineral mediums containing different compositions of cottonseed oil and valeric acid by Ralstonia sp. JC-64. The melting temperature (T _m ) of polyhydroxybutyrate from cottonseed oil was 174°C and that of P(3HB-co-3HV) with the highest 3HV-mol fraction (62%) was 81°C.     

Metabolites of microorganisms. 143. Echinocandin B, a novel polypeptide-antibiotic from Aspergillus nidulans var. echinulatus: isolation and structural components

From a strain of Aspergillus nidulans var. echinulatus, A 32204, echinocandin, a novel polypeptide antibiotic complex with high and specific anti-yeast activity was isolated. The main component, echinocandin B, was separated by counter-current distribution. A tentative molecular formula C₅₂H₈₁N₇O₁₈ is discussed. The antibiotic is characterized by its IR. and NMR. spectra and by its characteristic hydrolytic degradation products: linoilic acid, L -4-hydroxyproline, L -4-oxoproline, (2S, 3S, 4S)-4-methyl-3-hydroxy-proline, L -threonine (2 mols), and 1-(p-hydroxyphenyl)-3-amino-propan-2-one.     

Synthesis,characterization, molecular docking,analgesic, antiplatelet and anticoagulant effects of dibenzylidene ketone derivatives

In this study dibenzylidene ketone derivatives (2E,5E)-2-(4-methoxybenzylidene)-5-(4-nitrobenzylidene) cyclopentanone (AK-1a) and (1E,4E)-4-(4-nitrobenzylidene)-1-(4-nitrophenyl) oct-1-en-3-one (AK-2a) were newly synthesized, inspired from curcuminoids natural origin. Novel scheme was used for synthesis of AK-1a and AK-2a. The synthesized compounds were characterized by spectroscopic techniques. AK-1a and AK-2a showed high computational affinities (E-value >???9.0 kcal/mol) against cyclooxygenase-1, cyclooxygenase-2, proteinase-activated receptor 1 and vitamin K epoxide reductase. AK-1a and AK-2a showed moderate docking affinities (E-value >???8.0 kcal/mol) against mu receptor, kappa receptor, delta receptor, human capsaicin receptor, glycoprotein IIb/IIIa, prostacyclin receptor I₂, antithrombin-III, factor-II and factor-X. AK-1a and AK-2a showed lower affinities (E-value >???7.0 kcal/mol) against purinoceptor-3, glycoprotein-VI and purinergic receptor P₂Y₁₂. In analgesic activity, AK-1a and AK-2a decreased numbers of acetic acid-induced writhes (P?<?0.001 vs. saline group) in mice. AK-1a and AK-2a significantly prolonged the latency time of mice (P?<?0.05, P?<?0.01 and P?<?0.001 vs. saline group) in hotplate assay. AK-1a and AK-2a inhibited arachidonic acid and adenosine diphosphate induced platelet aggregation with IC₅₀ values of 65.2, 37.7, 750.4 and 422 µM respectively. At 30, 100, 300 and 1000 µM concentrations, AK-1a and AK-2a increased plasma recalcification time (P?<?0.001 and P?<?0.001 vs. saline group) respectively. At 100, 300 and 1000 µg/kg doses, AK-1a and AK-2a effectively prolonged bleeding time (P?<?0.001 and P?<?0.01 vs. saline group) respectively. Thus in-silico, in-vitro and in-vivo investigation of AK-1a and AK-2a reports their analgesic, antiplatelet and anticoagulant actions.     

In situ X-ray diffraction study of reduction processes of Fe3O4- and Fe1−xO-based ammonia-synthesis catalysts

The temperature-programmed reduction process of two types of industrial ammonia-synthesis catalysts, A110 and ZA-5, which are, respectively, based on Fe₃O₄ and Fe_1−xO precursors, were studied by in situ X-ray power diffraction (XRD). It has been found that the ZA-5 has lower reduction temperature and faster reduction rate, and its active phase α-Fe possesses a higher value of lattice microstrain than A110. The simulation based on Rietveld refinement has also shown that the shape of α-Fe grain of ZA-5 has a mixed shape of cube and sphere with more exposing (111) and (211) planes, while that of A110 looks like a concave cube with more exposing (110) planes. Based on the results obtained, a growth model of α-Fe during the reduction of Fe₃O₄- and Fe_1−xO-based ammonia-synthesis catalysts is proposed, and the origins for the activity difference has been also discussed.     

Cytotoxic metabolites of <Emphasis Type="Italic">Streptimonospora salina</Emphasis>

Streptimonospora salina gen. nov., sp. nov. was found to produce three phenoxazinone antibiotics, 2-amino-3H-phenoxazin-3-one (1), 2-methylamino-3H-phenoxazin-3-one (2), 2-acetylamino-3H-phenoxazin-3-one (3), and one phenazine antibiotic, phenazine-1-carboxylic acid (4). The chemical structures of the compounds were determined using 1D and 2D NMR spectrometry and electrospray mass spectrometry (ESMS). Compounds 1-4 exhibited modest cytotoxicity against a human renal carcinoma cell line ACHN with IC₅₀ values of 35.4, 12.4, 65.4, and 82.9 μM, respectively. Compound 2 was discovered for the first time from a biological origin. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 405–406, July–August, 2008     

The influence of film thickness and process temperature on <Emphasis Type="Italic">c</Emphasis>-axis orientation of Bi<Subscript>3</Subscript>TiTaO<Subscript>9</Subscript> thin films

Bi-layered ferroelectric Bi₃TiTaO₉ (BTT) thin films with different thickness (ranging from 100 to 400 nm) were successfully fabricated on Pt(111)/TiO₂/SiO₂/(100)Si substrates using chemical solution deposition (CSD) technique at different annealing temperatures. The c-axis orientation of the films was affected by film thickness and process temperature. The thinner the film and the higher the process temperature, the higher the c-axis orientation. With the increase of film thickness, the stress decreased but the film roughness increased, which led to the decrease of c-axis orientation of films. BTT films annealed at 800°C were found to have much improved remament polarization (P _r ) than that of films annealed at 650 and 750°C. The P _r and coercive field (E _c ) values were measured to be 2 μC/cm² and 100 kV/cm, respectively. BTT films showed well-defined ferroelectric properties with grain size larger than 100 nm.     

Medium Optimization Based on Statistical Methodologies for Pristinamycins Production by <Emphasis Type="Italic">Streptomyces pristinaespiralis</Emphasis>

The optimization of nutrient levels for the production of pristinamycins by Streptomyces pristinaespiralis CGMCC 0957 in submerged fermentation was carried out using the statistical methodologies based on the Plackett–Burman design, the steepest ascent method, and the central composite design (CCD). First, the Plackett–Burman design was applied to evaluate the influence of related nutrients in the medium. Soluble starch and MgSO₄·7H₂O were then identified as the most significant nutrients with a confidence level of 99%. Subsequently, the concentrations of the two nutrients were further optimized using response surface methodology of CCD, together with the steepest ascent method. Accordingly, a second-order polynomial regression model was finally fitted to the experimental data. By solving the regression equation from the model and analyzing the response surface, the optimal levels for soluble starch and MgSO₄·7H₂O were determined as 20.95 and 5.67g/L, respectively. Under the optimized medium, the yield of pristinamycins in the shake flask and 5-L bioreactor could reach 1.30 and 1.01g/L, respectively, which is the highest yield reported in literature to date.     

Reactions of isomeric 3,6- and 3,5-di-tert-butyl-ortho-benzoquinones with NH3

The interaction of 3,6-di-tert-butyl-ortho-benzoquinone (1) and 3,5-di-tert-butyl-ortho-benzoquinone (2) with NH₃ in water—alcohol medium and with (NH₄)₂CO₃ in a solid phase has been studied. Redox processes with participation of a nucleophile of the medium take place for1, while2 reacts with NH₃ at the carbonyl group with transformation of the quinone imide. The mechanism of redox transformation of1 has been proposed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1789–1793, September, 1995.This work was carried out with financial support from the Russian Foundation for Basic Research (Project No. 94-03-08653).     

Stoffwechselprodukte von Mikroorganismen. 231. Mitteilung. Bafilomycin-A1-21-O-(α-L-rhamnopyranosid): Strukturaufklärung durch chemische Verknüpfung mit Bafilomycin A1 und Leucanicidin

Isolation of Bafilomycin-A₁-21-O-(α-L-rhamnopyranoside). Structural Determination by Chemical Correlation with Bafilomycin A₁ and Leucanicidin From cultures of an actinomycete strain, the known antifungal and insecticidal antibiotic leucanicidin ( 1 ) and a hitherto unknown antifungal antibiotic, bafilomycin-A₁-21-O-(α-L-rhamnopyranoside) ( 2 ), were isolated. The latter is spectroscopically closely related to 1 and bafilomycin A₁ ( 3 ) and gave degradation products identical with compounds obtained by analogous degradation of 1 and 3 .     

Molecular structure and thermal stability of α-halogen-<Emphasis Type="Italic">gem</Emphasis>-dithiols

The electronic structure of α-halogen-gem-dithiols RC(SH)₂CH₂X (R = Me, Ph; X = F, Cl, Br, I) was studied by quantum chemistry methods. Four most stable rotamers were located, differing in the mutual orientation of the thiol groups and the halogen atom. The thermodynamic and kinetic characteristics of the thermolysis of α-halogen-gem-dithiols were obtained. Thermolysis of chlorine- and bromine-substituted gem-dithiols depends on the properties of the medium, namely, in aprotic media aromatic dithiols form trithianorbornane derivatives while aliphatic dithiols form thiirane derivatives. In an aqueous medium (R = Me, Ph), water promoted elimination of hydrogen sulfide with the formation of corresponding thiones is more preferable. Thermolysis of aliphatic iodine-substituted gem-dithiols proceeds as bimolecular deiodination resulting in the formation of a new C-C bond.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 559–568, March, 2005.     

New octahedral Zn<Superscript>II</Superscript> and Cd<Superscript>II</Superscript> complexes based on azo derivatives and azomethines of pyrazole-5-thione

New metal chelates of Zn^II and Cd^II (ML₂) based on (4Z)-3-methyl-1- phenyl-5-thioxo-1,5-dihydro-4-H-pyrazol-4-one quinolin-8-ylhydrazone (HL¹) and (4Z)-5- methyl-2-phenyl-4-[(quinolin-8-ylimino)methyl]-2,4-dihydro-3H-pyrazole-3-thione (HL²) were synthesized. The structures of the metal chelates were studied by EXAFS and NMR (¹H, ¹³C, and ¹¹¹Cd) spectroscopy. The structure of the Cd(L¹)₂ complex was established by X-ray diffraction analysis. The complexes have pseudooctahedral structures with the N₄S₂ ligand environment.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 623–629, March, 2005.     

Stereoselective synthesis of (±)-indolizidines 167B and 209D and theirtrans-isomers based on the reductive allylboration of pyridine

A general method for the synthesis of 5-substituted indolizidines based on intramolecular cyclization oftrans- andcis-2-allyl-6-R-1,2,3,6-tetrahydropyridines, obtained from pyridine and triallylborane, has been elaborated. The closure of the five-membered ring is carried out by hydroboration-oxidation followed by cyclization of the resulting δ-amino alcohols in the presence of the Ph₃P−CBr₄−Et₃N system. (Pr₂BH)₂ and Pr₃B are used as the hydroborating reagents, and H₂O₂ in an acid medium is used for the oxidation of 2-[3-(dipropylboryl]-Δ²-piperideines formed. This method has been used for the synthesis of two natural alkaloids: indolizidine 209D (cis-5-hexylindolizidine) and itstrans-isomer were prepared fromcis- andtrans-2-allyl-6-hexyl-1,2,3,6-tetrahydropiridine, respectively; indolizidine 167B andtrans-5-propylindolizidine were synthesized fromcis- andtrans-2,6-diallyl-1,2,3,6-tetra-hydropyridine, respectively. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 971–979, May, 1998.     

Stoffwechselprodukte von Mikroorganismen. 253. Mitteilung. Hormaomycin,ein neues Peptid-lacton mit morphogener Aktivität auf Streptomyceten

Hormaomycin, a Novel Peptide Lactone with Morphogenetic Activity on Streptomyces A culture identified as Streptomyces griseoflavus (strain W-384) has been found to produce a novel peptide-lactone antibiotic designated hormaomycin ( 6 ). The empirical molecular formula of the compound is established to be C₅₅H₆₉ClN₁₀O₁₄. The constituent amino acids of the antibiotic are suggested to be allothreonine ( 1 ; 1), isoleucine ( 2 ; 1), 3-methyl-phenylalanine ( 3 ; 2), and, for the first time identified from a natural source, 4-[(Z)-prop-1-enyl]-proline ( 4 ; 1) and 3-(2-nitrocyclopropyl)-alanine ( 5 ; 2). The amino acids were delivered by acidic hydrolysis and assigned by high-resolution- GC/MS analysis (after transformation to derivatives) in combination with extended 2D-NMR experiments of the antibiotic itself. From the latter, it became plausible that the N-terminus of the peptide chain is acylated by a Cl-containing derivative of 1H-pyrrol-2-carboxylic acid. Hormaomycin is active against some Gram-positive bacteria. In addition, the antibiotic exhibits potent aerial mycelium-inducing activity and effects the production of antibiotics.     

Production of bacterial cellulose by Gluconacetobacter sp. RKY5 isolated from persimmon vinegar

The optimum fermentation medium for the production of bacterial cellulose (BC) by a newly isolated Gluconacetobacter sp. RKY5 was investigated. The optimized medium composition for cellulose production was determined to be 15 g/L glycerol, 8 g/L yeast extract, 3 g/L K₂HPO₄, and 3 g/L acetic acid. Under these optimized culture medium, Gluconacetobacter sp. RKY5 produced 5.63 g/L of BC after 144 h of shaken culture, although 4.59 g/L of BC was produced after 144 h of static culture. The amount of BC produced by Gluconacetobacter sp. RKY5 was more than 2 times in the optimized medium found in this study than in a standard Hestrin and Shramm medium, which was generally used for the cultivation of BC-producing organisms.     

Order‐Order Transition of C → sdG → sL → S in ABC Triblock Copolymer Thin Film Induced by Solvent Vapor

The morphology transition of polystyrene‐block‐poly(butadiene)‐block‐poly(2‐vinylpyridine) (SBV) triblock thin film induced in benzene vapor showing weak selectivity for PS is investigated. The order‐order transitions (OOT) in the sequence of core‐shell cylinders (C), sphere in ‘diblock gyroid’ (sdG), sphere in lamella (sL) and sphere (S) are observed. The projection along (111) direction in Gyroid phase (sdG(111)) is found to epitaxially grow from C(001) in the film. Instead of sdG(111), sdG(110)_0.1875 develops to the phase of sL. Consequently, the film experiences the transition sequence of sdG(111) → sdG(211) → sdG(110)_0.25 → sdG(110)_0.1875 between C and sL. The mechanism is analyzed from the total surface area of the blocks.

     

Molecular Engineering of Redox Rich Diruthenium Compounds: Further Investigation of Ru<Subscript>2</Subscript>(Y<Emphasis Type="Italic">ap</Emphasis>)<Subscript>4</Subscript>X Type Compounds

Three new diruthenium compounds, Ru₂(L1)₄Cl (1), Ru₂(L2)₄Cl (2) and Ru₂(ap)₄F (3) were synthesized and characterized, where L1, L2, and ap are 2-(3-methoxyanilino)pyridinate, 2-(3-propoxyanilino)pyridinate, and 2-anilinopyridinate, respectively. Structural study revealed the Ru–Ru bond lengths of 2. 2816(7) Å (1) and 2. 2785(6) Å (3). All three compounds are S = 3/2 molecules. Each of three diruthenium compounds displays two reversible one electron couples, an oxidation and a reduction, and the potential data appear to indicate that the axial fluoro ligand is a much stronger donor than the chloro ligand.     

In Situ Investigation of Methane Dry Reforming on Metal/Ceria(111) Surfaces: Metal–Support Interactions and C−H Bond Activation at Low Temperature

Studies with a series of metal/ceria(111) (metal=Co, Ni, Cu; ceria=CeO₂) surfaces indicate that metal–oxide interactions can play a very important role for the activation of methane and its reforming with CO₂ at relatively low temperatures (600–700 K). Among the systems examined, Co/CeO₂(111) exhibits the best performance and Cu/CeO₂(111) has negligible activity. Experiments using ambient pressure X‐ray photoelectron spectroscopy indicate that methane dissociates on Co/CeO₂(111) at temperatures as low as 300 K—generating CH_x and CO_x species on the catalyst surface. The results of density functional calculations show a reduction in the methane activation barrier from 1.07 eV on Co(0001) to 0.87 eV on Co²⁺/CeO₂(111), and to only 0.05 eV on Co⁰/CeO_2−x (111). At 700 K, under methane dry reforming conditions, CO₂ dissociates on the oxide surface and a catalytic cycle is established without coke deposition. A significant part of the CH_x formed on the Co⁰/CeO_2−x (111) catalyst recombines to yield ethane or ethylene.     

Preparation of highly (111)-oriented (Pb,La)(Zr,Sn,Ti)O<Subscript>3</Subscript> (PLZST) antiferroelectric thin films by modified sol-gel process using a novel tin source,dibutyloxide of tin

Highly (111)-oriented Pb_0.97La_0.02Zr_0.85Sn_0.13 Ti_0.02O₃(PLZST) antiferroelectric thin films were deposited on Pt(111)/Ti/SiO₂/Si(100) substrates through a modified sol-gel process technique. The electric field-induced antiferroelectric-to-ferroelectric (AFE‐FE) phase transformation behaviour was examined by C-V measurement. The results indicated that antiferroelectric (AFE) to ferrroelectric (FE) switching field , FE to AFE switching field were 315 kV/cm and 240 kV/cm respectively. The temperature dependence of the dielectric constant showed that the Curie temperature (T _c) of the PLZST antiferroelectric thin films was 171°C. The voltage dependent current density of the highly (111)-oriented PLZST film was less than 1.3 × 10⁻⁶ A/cm² over electric field range from 0 to ± 427 kV/cm.     

ESR investigation of paramagnetic derivatives of [6-<Emphasis Type="Italic">tert</Emphasis>-butyl-4-(5-<Emphasis Type="Italic">tert</Emphasis>-butyl-2-methyl-3,4-dioxocyclohexa-1,5-dien-1-yl)-3-methylcatecholato]triphenylantimony(V)

A number of paramagnetic derivatives of [6-tert-butyl-4-(5-tert-butyl-2-methyl-3,4-dioxocyclohexa-1,5-dien-1-yl)-3-methylcatecholato]triphenylantimony(v) were investigated by ESR spectroscopy. The reactions of this complex with Cp₂Co or LiCl in the presence of Hg_metal. lead to the formation of free (nonchelated) radical anion semiquiones. Chelated complexes are formed in the case of Tl(Hg), Mn₂(CO)₁₀, Re₂(CO)₁₀, Sn₂Ph₆, Cu(met.), and CuCl + dppfc (dppfc is bis-diphenylphosphinoferrocene). Dedicated to Academician A. L. Buchachenko on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2004–2009, September, 2005.     

Coverage‐Controlled Superstructures of C3‐Symmetric Molecules: Honeycomb versus Hexagonal Tiling

The competition between honeycomb and hexagonal tiling of molecular units can lead to large honeycomb superstructures on surfaces. Such superstructures exhibit pores that may be used as 2D templates for functional guest molecules. Honeycomb superstructures of molecules that comprise a C₃ symmetric platform on Au(111) and Ag(111) surfaces are presented. The superstructures cover nearly mesoscopic areas with unit cells containing up to 3000 molecules, more than an order of magnitude larger than previously reported. The unit cell size may be controlled by the coverage. A fairly general model was developed to describe the energetics of honeycomb superstructures built from C₃ symmetric units. Based on three parameters that characterize two competing bonding arrangements, the model is consistent with the present experimental data and also reproduces various published results. The model identifies the relevant driving force, mostly related to geometric aspects, of the pattern formation.