Isolation and Characterization of an Antimicrobial Polypeptide from Loach

Hydrobionts formed their special defense systems during evolution. One such system is that of non-specific immunity which comprises a wide variety of peptides with potent antimicrobial activities1. The mechanism of action of most antimicrobial peptides was reported as that a few peptide molecules formed a channel on cell membrane, and the cell was then died of the outflowing of cellular contents. The above mechanism was different from that of antibiotics2, 3. It is a promising area to disc…     

A method for isolating functional RNA from callus of Dendrobium candidum contented rich polysaccharides

Isolation of high-quality RNA from Dendrobium candidum is particularly difficult. D. candidum contains considerable amounts of polysaccharides that coprecipitate with RNA, which render RNA unsuitable for either cDNA synthesis and/or PCR amplification. In this paper, a rapid and efficient method was described for functional RNA isolation from the callus of D. candidum. The procedure included: (i) an extraction with phenol and isopropyl alcohol, to remove proteins and polyphenols; (ii) purifications by lithium chloride, pre-cooled (−20 °C) ethanol successively to remove polysaccharides. The method resulted in high-quality RNA suitable for DDRT-PCR and cDNA library analysis finally.     

Isolation of an urate-binding protein by affinity chromatography

This paper describes an affinity chromatography procedure to purify an urate binding protein from human serum. The specific ligand was 8-amino-2,6-dihydroxypurine bound to Sepharose through the amino group. The specific elution was obtained with an uric acid or allopurinol solution. Electrophoretic analysis of the eluted protein shows a single sharp band with an α₂-globulin mobility. Molecular weight, determined by gel filtration, is approximately 70,000 daltons.     

低温基体隔离Mn_1(CO)_(10)的紫外激光光解

采用280nm和355nm的脉冲激光作光解光源,由FTIR进行初级产物探测,研究了Mn_2(CO)_(10)在低温基体隔离条件下的光解反应.结果表明,在Ar基体中,Mn_2(CO)_(10)经280nm激光光解的初级产物主要是Mn_2(CO)_9;而在Xe基体中还观察到了Mn(CO)_5的生成;与280nm激光相比,采用355nm激光光解Mn_2(CO)_(10),Mn_2(CO)_9的产率较低.     

Matrix isolation and ab initio studies of the H2S---CO complex

The structure, energetics, and vibrational properties of complexes formed between H₂S and CO have been investigated by matrix isolation FTIR spectroscopy and ab initio molecular orbital theory. Two stable computational minima were found representing nearly linear hydrogen bonds between the subunits. The H₂S---CO and H₂S---OC species were calculated to be bound by 5.22 and 1.54 kJ mol⁻¹, respectively. The computational results were reproduced by experimental assignments for the carbon attached complex. The stretching vibrations of the complex subunits were found to be similarly perturbed upon complexation both experimentally and computationally.     

CH3--MoF], [CH2=MoHF], and [CH[triple bond]MoH2F] formed by reaction of laser-ablated molybdenum atoms with methyl fluoride: persistent photoreversible interconversion through alpha-hydrogen migration and agostic interaction

Simple molybdenum methyl, carbene, and carbyne complexes, [CH3--MoF], [CH2=MoHF], and [CH[triple chemical bond]MoH(2)F], were formed by the reaction of laser-ablated molybdenum atoms with methyl fluoride and isolated in an argon matrix. These molecules provide a persistent photoreversible system through alpha-hydrogen migration between the carbon and metal atoms: The methyl and carbene complexes are produced by applying UV irradiation (240-380 nm) while the carbyne complex is depleted, and the process reverses on irradiation with visible light (lambda>420 nm). An absorption at 589.3 cm(-1) is attributed to the Mo--F stretching mode of [CH3--MoF], which is in fact the most stable of the plausible products. Density functional theory calculations show that one of the alpha-hydrogen atoms of the carbene complex is considerably bent toward the metal atom (angle-spherical HCMo=84.5 degrees ), which provides evidence of a strong agostic interaction in the triplet ground state. The calculated C[triple chemical bond]Mo bond length in the carbyne is in the range of triple-bond values in methylidyne complexes.     

C-C double- and triple-bond formation from reactions of B atoms with CO: experimental and theoretical characterization of OBBCCO and OBCCBO molecules in solid argon

Reactions of boron atoms with CO molecules in solid argon form the following boron carbonyl species (which have been reported earlier): BCO, BBCO, OCBBCO, B(CO)2, and B4(CO)2. The OCBBCO molecule underwent a photochemical rearrangement where CO was activated to form the OBBCCO and OBCCBO molecules. The new molecules were identified on the basis of isotopic IR studies with 10B, 11B, 13C16O, 12C18O, and carbon dioxide mixtures in addition to comparison with quantum-chemical calculations of isotopic frequencies. Theoretical analyses showed that the OBBCCO and OBCCBO molecules are linear with C-C double and triple bonding, respectively, and lie at a much lower energy than the linear OCBBCO structure.     

Investigation of particle isolation in Li-ion battery electrodes using Li NMR spectroscopy

⁷Li MAS NMR spectroscopy was used to study the failure mechanisms of LiNi_0.8Co_0.15Al_0.05O₂ electrodes in Li-ion cells. Three sets of electrodes with different degrees of power fade (0%, 9% and 23%) were studied. The three electrodes were charged to various states of charge (0%, 40%, 60%, 80% and 100%) in pouch cells which were subsequently disassembled for NMR analysis. The lithium NMR shifts of the positive electrodes in the different states of charge were investigated. The results indicate that NMR spectroscopy can be used to probe particle isolation in these electrodes. Particle isolation is responsible for the capacity and power fades since some of the active material particles are disconnected from the matrix. This study also clearly showed the loss of electrochemically active lithium as the power fade increased.     

A high-performance liquid chromatographic method for the measurement of amiodarone and its main metabolite (desethylamiodarone) in plasma samples from patients treated withCordarex ®

Summary A procedure for the rapid, quantitative isolation of amiodarone and its main metabolite (desethylamiodarone) from plasma with SEP-PAK silica cartridges is described together with a sensitive high performance liquid chromatographic assay for the quantitative determination of the drugs.The recovery of amiodarone and its metabolite was greater than 80% over an investigated range of 0.1–5g/ml of plasma and the limit of quantitation by the assay was 50 ng/ml of plasma.The column extraction of amiodarone and its metabolite coupled with the chromatographic versatility of the method make it suited for either detailed pharmacokinetic studies and routine plasma analysis of amiodarone.     

Superfluid helium droplets: a uniquely cold nanomatrix for molecules and molecular complexes

Herein, recent experiments on the spectroscopy and chemical reactions of molecules and complexes embedded in helium droplets are reviewed. In the droplets, a high spectroscopic resolution, which is comparable to the gas phase is achieved, while an isothermal low-temperature environment is maintained by evaporative cooling at T =0.37 K (4He droplets) or 0.15 K (3He droplets), lower than possible in most solid matrices. Thus the helium-droplet technique combines the benefits of both the gas phase and the classical matrix-isolation techniques. Most important, the superfluid helium facilitates binary encounters, and absorbs the released binding energy upon recombination. Thus the droplet can be viewed as an isothermal nanoscopic reactor, which isolates single molecules, clusters, or even a single reactive encounter at ultralow temperatures.