Biosynthesis of lambertellols based on the high specific incorporation of the 13C-labeled acetates and their biological properties

Biosyntheses of lambertellols A (1) and B (2) as well as lambertellin (3) were investigated by isotope labeling experiments. Nearly 40% of specific incorporation of [1,2-(13)C(2)]acetate was achieved, and all the carbons in 1 and 2 were labeled. This high incorporation of the labeled acetate was realized by providing INADEQUATE spectra by employing only 0.4 and 0.7 mg of 1 and 2, respectively. Our studies revealed that 1-3 are biogenetically synthesized via loss of two carbons from octameric acetate. A biological assay against Monilinia fructicola revealed those remarkably inhibited hyphal germinations. However, neither of them killed the spores immediately, even in high concentration. These conditions induced the formation of microconidia.     

Cytotoxic major saponin from tomato fruits

A major novel steroidal alkaloid glycoside, possessing cytotoxic activity has been isolated from the fruits of Lycopersicon esculentum.     

Description of molecular dynamics in intense laser fields by the time-dependent adiabatic state approach: application to simultaneous two-bond dissociation of CO2 and its control

We theoretically investigated the dynamics of structural deformations of CO(2) and its cations in near-infrared intense laser fields (approximately 10(15) W cm(-2)) by using the time-dependent adiabatic state approach. To obtain "field-following" adiabatic potentials for nuclear dynamics, the electronic Hamiltonian including the interaction with the instantaneous laser electric field is diagonalized by the multiconfiguration self-consistent-field molecular orbital method. In the CO(2) and CO(2+) stages, ionization occurs before the field intensity becomes high enough to deform the molecule. In the CO(2)(2+) stage, simultaneous symmetric two-bond stretching occurs as well as one-bond stretching. Two-bond stretching is induced by an intense field in the lowest time-dependent adiabatic state |1> of CO(2)(2+), and this two-bond stretching is followed by the occurrence of a large-amplitude bending motion mainly in the second-lowest adiabatic state |2> nonadiabatically created at large internuclear distances by the field from |1>. It is concluded that the experimentally observed stretched and bent structure of CO(2)(3+) just before Coulomb explosions originates from the structural deformation of CO(2)(2+). We also show in this report that the concept of "optical-cycle-averaged potential" is useful for designing schemes to control molecular (reaction) dynamics, such as dissociation dynamics of CO(2), in intense fields. The present approach is simple but has wide applicability for analysis and prediction of electronic and nuclear dynamics of polyatomic molecules in intense laser fields.     

Flow injection determinations of polyphosphates based on colored metal complexes of xylenol orange and methylthymol blue

Substitution reactions between samples and colored metal complexes, such as magnesium-methylthymol blue and cerium(III)-xylenol orange, are applied to flow injection determinations of orthophosphate, diphosphate, triphosphate and EDTA. Various types of manifold with a stopped-flow device are used; the importance of addition of reagents in a logical sequence is stressed. Kinetic and thermodynamic factors associated with the substitution reactions were found to be significantly reflected in the f.i.a. profiles and stopped-flow signals. The working ranges of the methods are 10^-5–10^-4 M.     

Vibrational analysis of the SO+ (A2Π−χ2Πr) emission system by an isotopic study

Absolute vibrational quantum numbers for the SO⁺ (A²Π—χ²Π_r) emission system have been determined by measurement of isotope shifts between S¹⁶O⁺ and S¹⁸O⁺ bands. It has been found that the tentative ν″ values reported previously should be decreased by one vibrational quantum number, The definite molecular constants for the SO⁺ (A²Π,χ²Π_r) states are determined and compared with photoelectron spectroscopic data.     

Formation of covalent nuclear molecules in the 13C + 12C system

Angular distribution's of the elastic scattering of ¹³C on ¹²C and the inelastic scattering leading to the lowest-lying $\text{1}\text{2}{}^{\mathrm{+}}$ and $\text{5}\text{2}{}^{\mathrm{+}}$ states in ¹³C have been measured at energies close to the Coulomb barrier. Analyses carried out in the framework of a complete coupled-reaction-channel theory show that extremely polarized single-particle molecular orbits (hybridization) are formed during the scattering process which give rise to a multiple-step interaction of the valence nucleon, i.e. the formation of a covalent nuclear molecule.     

Flow injection analysis of inorganic polyphosphates

Flow injection analysis is applied to the determination of orthophosphate and polyphosphates, such as diphosphate and triphosphate. A strongly acidic solution containing molybdenum(V) and molybdenum(VI) is used as the carrier so that hydrolysis of polyphosphates and color development of the resultant orthophosphate can be achieved simultaneously. For complete chemical reaction, the temperature of the reaction coil is maintained at 140° C. Application of a back-pressure coil is then necessary to eliminate the noise caused by gas bubbles. Total amounts of inorganic polyphosphates can be determined at a sampling rate of 45 samples per hour with a relative standard deviation of less than 1%. In addition, the flow injection system is shown to be useful as a post-column detector for high-performance liquid chromatography of inorganic polyphosphates. The efficiency of this system is compared with that of an air-segmented flow system.