Publications by authors named "Daran J"

The title compound, C(23)H(31)NO, was semisynthesized from isocostic acid, isolated from the aerial part of Inula Viscosa- (L) Aiton [or Dittrichia Viscosa- (L) Greuter]. The cyclo-hexene ring has a half-chair conformation, whereas the cyclo-hexane ring displays a chair conformation. The dihedral angle between the latter ring and its substituent is 83.

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The tiltle complex, [La(2)(C(7)H(7)NO(2))(4)Cl(2)(H(2)O)(6)]Cl(4)·2H(2)O, is a centrosymmetric dimer formed by edge-sharing LaO(5)(H(2)O)(3)Cl polyhedra linked together by a carboxyl-ate ligand. The two La(III) metal ions are linked by two bidentate bridging carboxyl-ate groups with a κ(2)O:O' coordination mode and two bidentate chelating bridging carboxyl-ate groups with a κ(3)O:O,O' coordination mode. The coordination sphere of lanthanum, completed by a terminal chloride and three water mol-ecules, adopts a distorted tricapped trigonal-prismatic arrangement.

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The hop plant, Humulus lupulus L., has an exceptionally high content of secondary metabolites, the hop alpha-acids, which possess a range of beneficial properties, including antiseptic action. Studies performed on the mode of action of hop iso-alpha-acids have hitherto been restricted to lactic acid bacteria.

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Low-temperature (200 K) protonation of [Mo(CO)(Cp*)H(PMe(3))(2)] (1) by Et(2)OHBF(4) gives a different result depending on a subtle solvent change: The dihydrogen complex [Mo(CO)(Cp*)(eta(2)-H(2))(PMe(3))(2)](+) (2) is obtained in THF, whereas the tautomeric classical dihydride [Mo(CO)(Cp*)(H)(2)(PMe(3))(2)](+) (3) is the only observable product in dichloromethane. Both products were fully characterised (nu(CO) IR; (1)H, (31)P, (13)C NMR spectroscopies) at low temperature; they lose H(2) upon warming to 230 K at approximately the same rate (ca. 10(-3) s(-1)), with no detection of the non-classical form in CD(2)Cl(2), to generate [Mo(CO)(Cp*)(FBF(3))(PMe(3))(2)] (4).

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Activation of the cephalosporin side-chain precursor to the corresponding CoA-thioester is an essential step for its incorporation into the beta-lactam backbone. To identify an acyl-CoA ligase involved in activation of adipate, we searched in the genome database of Penicillium chrysogenum for putative structural genes encoding acyl-CoA ligases. Chemostat-based transcriptome analysis was used to identify the one presenting the highest expression level when cells were grown in the presence of adipate.

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Accumulation of glycogen and trehalose in nutrient-limited cultures of Saccharomyces cerevisiae is negatively correlated with the specific growth rate. Additionally, glucose-excess conditions (i.e.

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New stereodynamic diphosphinites derived from 2,2'-biphosphole, were synthesised by introduction of a linker obtained from chiral diols between the two phosphorus atoms and used for catalytic hydrogenation through a dual chirality control induced by Rh-coordination. The application of these ligands in hydrogenation of dimethyl itaconate shows that the enantioselectivity strongly depends on steric and electronic properties of the chiral linker whereas the sense of enantioselection is determined by the configuration of these stereocentres. These stereodynamic diphosphinites induce higher enantioselectivities than the analogous stereodynamic diphosphanes derived from 2,2-biphosphole.

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Saccharomyces cerevisiae strains belonging to the CEN.PK family are widely used in fundamental and applied yeast research. These strains have been reported to be hypersensitive to sodium ions and a previous microarray-based genotyping study indicated an atypical organization of the PMR2 locus.

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A new family of hexakis(ferrocenylethynyl)benzenes was synthesized by Negishi coupling from ethynylferrocenes and C(6)Br(6) and can be reversibly oxidized to stable hexaferrocenium salts (see picture, Ar(F)=[3,5-C(6)H(3)(CF(3))(2)]). Their cyclic voltammograms show a single six-electron wave, three distinct two-electron waves, or a cascade of six single-electron waves, depending on the electrolyte counterion and number of methyl substituents on the ferrocenyl groups.

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The complex [Co(II)(tmhd)(2)] (4; tmhd = 2,2,6,6-tetramethylhepta-3,5-dionato) has been investigated as a mediator for controlled radical polymerization of vinyl acetate (VAc) and compared with the analogue [Co(II)(acac)(2)] (1; acac = acetylacetonato). A relatively well controlled process occurs, after an induction time, with 2,2'-azobis(4-methoxyl-2,4-dimethylvaleronitrile) (V-70) as radical initiator at 30 degrees C. However, whereas the polymerization essentially stops after about six initiator half-lives in the presence of 1, it continues with a first-order rate law in the presence of 4.

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Penicillium chrysogenum was successfully engineered to produce a novel carbamoylated cephalosporin that can be used as a synthon for semi-synthetic cephalosporins. To this end, genes for Acremonium chrysogenum expandase/hydroxylase and Streptomyces clavuligerus carbamoyltransferase were expressed in a penicillinG high-producing strain of P.chrysogenum.

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The homologous recombination mechanism for DNA-repair is not predominant in most filamentous fungi, resulting in extremely low targeting efficiencies for molecular engineering. To increase the gene targeting efficiency, it is becoming common practice to inactivate the non-homologous end-joining (NHEJ) pathway that causes random integration, by deleting the fungal homologs of the human KU70 and KU80 genes that encode proteins functioning in the NHEJ pathway. This has been described for several filamentous fungi, but limited knowledge on the physiological consequences is available.

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Background: Since the discovery of the antibacterial activity of penicillin by Fleming 80 years ago, improvements of penicillin titer were essentially achieved by classical strain improvement through mutagenesis and screening. The recent sequencing of Penicillium chrysogenum strain Wisconsin1255-54 and the availability of genomics tools such as DNA-microarray offer new perspective.

Results: In studies on beta-lactam production by P.

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Background: Microorganisms adapt their transcriptome by integrating multiple chemical and physical signals from their environment. Shake-flask cultivation does not allow precise manipulation of individual culture parameters and therefore precludes a quantitative analysis of the (combinatorial) influence of these parameters on transcriptional regulation. Steady-state chemostat cultures, which do enable accurate control, measurement and manipulation of individual cultivation parameters (e.

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As part of a systematic investigation for a number of Fe(II) porphyrin complexes used as biomimetic models for cytochrome P450, crystals of the title compound, [K(C(18)H(36)N(2)O(6))][Fe(II)(C(64)H(64)N(8)O(4))(HS)], were prepared. The compound exhibits a non-planar conformation with major ruffling and saddling distortions. The average equatorial iron-pyrrole N atom [Fe-N(p) = 2.

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The title compound, C(18)H(16)N(2)O, is a new dihydro-pyridazin-3(2H)-one derivative synthesized in one step by condensation of α-benzyl-idene-γ-tolyl-butenolide with hydrazine. The mol-ecule is not planar; the tolyl and pyridazine rings are twisted with respect to each other making a dihedral angle of 27.35 (9)° and the benzyl ring is nearly perpendicular to the pyridazine ring with a dihedral angle of 85.

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Two diastereoisomers of the title compound, C(25)H(26)N(2)O, have been prepared by cyclo-addition between 1,3,3-trimethyl-2-methyl-eneindoline and C-phenyl-N-phenyl-nitrone. The stereochemistry of the major diastereoisomer, viz. S,R/R,S, is confirmed by the X-ray analysis.

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The compound [Cp*Mo(PMe3)3H] (1) is reversibly oxidized at E1/2 = -1.40 V vs ferrocene in MeCN. Its oxidation with Cp2FePF6 yields thermally stable [Cp*Mo(PMe3)3H]PF6 (2), which has been isolated and characterized by IR and EPR spectroscopy and by single-crystal X-ray diffraction.

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Chemostat cultivation of micro-organisms offers unique opportunities for experimental manipulation of individual environmental parameters at a fixed, controllable specific growth rate. Chemostat cultivation was originally developed as a tool to study quantitative aspects of microbial growth and metabolism. Renewed interest in this cultivation method is stimulated by the availability of high-information-density techniques for systemic analysis of microbial cultures, which require high reproducibility and careful experimental design.

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Industrial penicillin production with the filamentous fungus Penicillium chrysogenum is based on an unprecedented effort in microbial strain improvement. To gain more insight into penicillin synthesis, we sequenced the 32.19 Mb genome of P.

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Whereas for 3-fluorodihydropyridine-substituted carboxylic acids electrophiles such as HCl, iodine, bromine and peracids discriminate the double bond lacking and that bearing fluorine, no such differentiation took place in the case of electrophilic fluorine since the formation of both mono and gem-difluorolactones took place.

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Reduction of compound "Pd(bcope)(OTf)2" [bcope = (c-C8H14-1,5)PCH2CH2P(c-C8H14-1,5); OTf = O3SCF3] with H2/CO yields a mixture of Pd(I) compounds [Pd2(bcope)2(CO)2](OTf)2 (1) and [Pd2(bcope)2(mu-CO)(mu-H)](OTf) (2), whereas reduction with H2 or Ph3SiH in the absence of CO leads to [Pd3(bcope)3(mu3-H)2](OTf)2 (3). Exposure of 3 to CO leads to 1 and 2. The structures of 1 and 3 have been determined by X-ray diffraction.

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Diphosphine sulfides derived from 2,2'-biphosphole have been efficiently synthesized in an enantiomerically pure form by a four step synthetic sequence. These S,S-ligands were used for the first time in Pd-catalyzed asymmetric allylic alkylation. Good yields and enantiomeric excess up to 73% were obtained.

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Two ternary copper(ll) complexes of indomethacin [1-(4-chlorobenzoyl)-5-methoxy-2- methyl-1-H-indole-3-acetic acid] called hereafter lndo, were prepared and characterized by single crystal X-ray diffraction. The first complex Cu(2)(Indo)(4)(DMF)(2) I crystallizes in space group P-1 (a = 10.829(2), b = 13.

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