The effect of ampicillin on the electrophysical properties of Escherichia coli cells

The study of the effect of ampicillin on the electrophysical properties of Escherichia coli cells showed that this antibiotic influences the orientational spectra (OSs) of the ampicillin-susceptible E. coli strains K-12 and XL-1 within the frequency range 10–1000 kHz of the orienting electric field and does not affect the OSs of the ampicillin-resistant strains K-12(pUC-18) and XL-1(pHEN1). The change in the electrooptical signal of the ampicillin-susceptible cells was maximum at an ampicillin concentration of 50 µg/ml and did not depend on the exposure time. The conclusion is drawn that changes in the OSs of cells can be used to evaluate their resistance to ampicillin.Translated from Mikrobiologiya, Vol. 74, No. 1, 2005, pp. 126–131.Original Russian Text Copyright © 2005 by Guliy, Markina, Ignatov, Shchegolev, Zaitseva, Bunin, Ignatov.     

异穗卷柏的显微与近红外光谱鉴定研究

对两种不同类型的异穗卷柏(Selaginella heterostachysBaker)药材的外观形态、孢子与茎的显微特征及近红外光谱特征进行了比较研究。结果表明:两类异穗卷柏的植株性状虽有明显不同,但其孢子形态、茎的解剖特征及近红外漫反射光谱特征一致。研究结果为异穗卷柏物种分类与药材鉴定提供了依据。     

Synthesis, spectroscopic characterization and structural studies of mixed ligand complexes of Sr(II) and Ba(II) with 2-hydroxybenzophenone and salicylaldehyde, hydroxyaromatic ketones or β-diketones: Crystal structure of 2-HOC6H4C(O)C6H5

Reactions of Sr(II) and Ba(II) chlorides with 2-hydroxybenzophenone and salicylaldehyde, hydroxyaromatic ketones or β-diketones in 1:1:1 molar ratios have resulted in the formation of mixed ligand complexes of the type [MLL′(H₂O)₂] (M = Sr(II) or Ba(II); HL = 2-hydroxybenzophenone and HL′ = salicylaldehyde, 2-hydroxyacetophenone, 2-hydroxypropiophenone, pentane-2,4-dione, 1-phenylbutane-1,3-dione or 1,3-diphenylpropane-1,3-dione). These complexes have been characterized by elemental analyses, TLC, IR and ¹H NMR spectroscopy.     

Optical properties of Ag(tripod)X with tripod = 1,1,1-tris(diphenyl-phosphinomethyl)ethane and X = Cl and I: Intraligand and ligand-to-ligand charge transfer

The complexes Ag^I(tripod)X with tripod = 1,1,1-tris(diphenylphosphinomethyl)ethane and X⁻ = Cl⁻ and I⁻ are luminescent in solution at r.t. It is suggested that the emission is a phosphorescence which originates from a tripod intraligand state for X = Cl (λ_max = 464 nm) and a X⁻ → tripod ligand-to-ligand charge transfer state for X = I (λ_max = 482 nm).     

Preparation, structure, solid state and gas phase stability of the mixed neodymium nitrate-chloride complex NdCl(NO3)2{[(MeO)2PO]2C(OH)Bu}2

The preparation and structure of the mixed anion complex NdCl(NO₃)₂{[(MeO)₂PO]₂C(OH)^tBu}₂ are reported. Single crystal X-ray diffraction shows that the bisphosphonate is bonded via both phosphoryl groups and the nitrates act as bidentate ligands. Intramolecular H-bonding is seen between the OH and the coordinated nitrate and chloride ligands. Thermal decomposition in the solid state is by loss of methyl nitrate. Electrospray mass spectrometry shows that loss of chloride is preferred over loss of nitrate in the gas phase. Attempted preparation of NdCl₂(NO₃){[(MeO)₂PO]₂C(OH)^tBu}₂ leads to the formation of a product approximating to [Nd{^tBu(OH)C(PO₃H₂)₂}₂]₂H · NO₃ · (PO₄H₂)₂. Electrospray mass spectrometry and elemental analysis confirm the presence of the [^tBu(OH)C(PO₄H₂)₂]⁻ in the decomposition products.     

啤酒废酵母制备碱不溶性葡聚糖

以啤酒废酵母为原料,采用碱提法确定了碱不溶性葡聚糖的制备条件,使用1.0 mol.L-1的NaOH溶液,以固液比为1:5进行提取,45℃处理6 h。此条件下碱不溶性葡聚糖得率可达10.94%,其多糖质量分数可达91.57%。红外光谱分析显示产品为β-(1-3)键的葡聚糖,其中不含甘露聚糖。     

Quantum chemical insight on vibration spectra of silica systems

A set of silicate ions and corresponding lithium salts have been quantum chemically (QC) simulated in a “free molecule” approach. The infrared (IR), inelastic neutron scattering (INS), and Raman spectra have been simulated and fitted to the experimentally registered ones. The complete assignment of the vibrational bands along with the intensities and potential energy distribution has been performed. The applicability of the traditionally used quasimolecule Si–O–Si model to the interpretation of bands near 440–480 cm^? 1 and so-called “Boson” peak near 50 cm^? 1 has been critically discussed.     

The Action of Peptidases from Aspergillus sojae on Soybean Proteins

To elucidate the mechanism of light-activation of pyruvate P_L dikinase in maize leaf, the inactive form was purified to homogeneity from dark-treated leaves using an activation system to locate it. The purification procedure included ammonium sulfate-fractionation followed by conventional chromatography.

The homogeneous enzyme after maximal activation had a specific activity comparable to that of the active enzyme obtained from non-dark-treated plants. The enzyme was indistinguishable from the active one in its molecular size and charge and in the amino acid composition of its acid-hydrolysate.     

Spectrophotometric Determination of L-Malic Acid with a Malic Enzyme

Purified β-connectin solutions were treated with hydrostatic pressures of 300 and 600 MPa for 10 min, and irreversible changes in the proportions of the secondary structure of connectin were estimated from CD spectra. The CD spectra showed that pressure had little effect on the secondary structure.