海藻糖对盐渍海鳗肌动球蛋白影响的研究

本实验研究了海藻糖对盐渍海鳗肌动球蛋白的影响。差示量热扫描(DSC)分析结果表明,海藻糖对于肌肉蛋白质的热稳定性有保护作用;傅立叶转换-红外(FT-TR)分析表明,当海藻糖含量达到2.90%时,海藻糖对于肌动球蛋白(AM)的二级结构具有较好的稳定作用。表面疏水性及Ca2+-ATP酶活性及巯基含量等结果表明,当海藻糖含量大于2.90%时,海藻糖可以使得肌动球蛋白的疏水相互作用增加,减少巯基氧化和二硫键的形成。因此在盐渍过程中添加海藻糖并且其浓度达到2.90%时能够很好地保护肌动球蛋白稳定,进而改善腌鱼制品的风味与品质。

印度洋深海热液区贻贝足丝结构和性能特征研究

贻贝营半固着生活,依靠足丝将自己牢固地黏附在底物上。足丝的结构和性能对贻贝的正常生命活动至关重要。为研究热液区极端环境下深海贻贝足丝的结构和性能,采集了印度洋龙旂深海热液区的贻贝(Bathymodiolus marisindicus)足丝,对其力学特性、结构特征和组分进行了分析。力学性能测试发现与近海贻贝(Mytilus galloprovincialis)相比,B.marisindicus足丝的力学性能表现为模量小、弹性小、弹性缓冲较差。傅里叶变换红外光谱(Fourier Transform infrared spectrometer,FT-IR)分析显示深海热液区贻贝足丝的主要成分是胶原蛋白,官能团特征显示足丝蛋白含大量的β折叠结构,足丝近端和远端的二级结构梯度较小。扫描电镜(scanning electron microscope,SEM)结果显示热液区贻贝足丝表面光滑,内部结构呈纤维状整齐排列。氨基酸分析结果显示深海热液区贻贝足丝中甘氨酸、脯氨酸含量高于近海贻贝足丝,这可能会增加足丝蛋白中三螺旋结构的稳定性,使足丝在热液环境中保持性能稳定。热液区深海贻贝足丝独特的力学性能、结构特征和组分特征为研究热液区贻贝的环境适应性提供了一定的基础。

Preparation of Carboxymethyl Cellulose Fibers

Carboxymethyl cellulose(CMC) fibers were produced by extruding the CMC solution into the metal salt coagulation bath and collected with a winding machine.It was found that copper chloride,ferric chloride,cerium chloride,lanthanum chloride and aluminum nitrate solution could be used as coagulation bath to prepare CMC fibers,whereas the metal salt solutions,such as nickel chloride,zinc chloride,calcium chloride and magnesium chloride,could not.The fiber formation is due to the coordination between the carboxylates of CMC and metal ion.Fourier transform infrared spectroscopy(FTIR) was applied to studying the coordination mode of CMC and metal ion.The metal salt concentration,pH value and temperature of the coagulation bath affect the tenacity and elongation of the fiber.CMC fibers show good water uptake ability and can adsorb water more than 200% of its own weight.The mechanical behaviors of CMC fiber show dependence on environment humidity.

Molecular interactions between anticancer drugs and iodinated contrast media: An in vitro spectroscopic study

Purpose: The purpose of this study is to assess molecular interactions between several anticancer drugs and an iodinated contrast medium by Fourier transform infrared spectroscopy (FT-IR) and ultraviolet-visible spectroscopy (UV-Vis). Materials and Methods: Iopamidol (IPM) was used as an iodinated contrast medium, and mitomycin C (MTI), epirubicin hydrochloride (EPI), cisplatin (CDDP), 5-fluorouracil (5FU), irinotecan hydrochloride (CPT11), gemcitabine hydrochloride (dFdC), carboplatin (CBDCA), oxaliplatin (1OHP), paclitaxel hydrochloride (TAX) and docetaxel trihydrate (TXT) were used as anticancer drugs. For FT-IR, the purified IPM was mixed stoichiometrically with each anticancer drug as well as with a combination of MTI and EPI. After measuring each separated sample and the mixtures, the spectra of the mixtures were compared with the spectra of the sum of pure samples or the combination. For UV-Vis, IPM and anticancer drugs were dissolved in pure water;subsequently for the titration experiments, the mixtures were prepared by varying the molar ratio. IR absorption corresponds to stretching vibrations between atoms having covalent bonding, whereas UV-Vis spectra depend on molecular dynamics and shapes. Both UV-Vis and IR spectra change when there are molecular interactions such as aromatic ring stacking and hydrogen bonding. Result: IPM exhibited molecular interactions with MTI, EPI, CDDP, dFdC, CBDCA, 1OHP, TAX and TXT, as well as with the combination of MTI and EPI on FT-IR. However, molecular interactions were not observed on UV-Vis. Conclusion: Several anticancer drugs have molecular interactions with IPM, which could be clinically utilized for superselective intraarterial infusion chemotherapy.

Molecular modeling and spectroscopic studies on the binding of guaiacol to human immunoglobulin

The fluorogenic property of guaiacol was exploited for the first time to analyze the interaction with target protein as a probe by molecular modeling, fluorescence, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy. Molecular docking was performed to reveal the possible binding mode or mechanism and suggested that guaiacol can strongly bind to human immu- noglobulin (HIgG). It is considered that guaiacol binds to HIgG mainly by a hydrophobic interaction and there are two hydrogen bond interactions between the drug and the residues LEU 80 and ASP 65, which is in good agreement with the results from the experimental thermodynamic parameters (the enthalpy change △H0 and the entropy change △S0 were calculated to be 65.55 kJ·mol-1 and 132.95 J·mol-1·K-1 according to the Vant’ Hoff equation). Data obtained by the fluorescence spectroscopy indicated that binding of guaiacol with HIgG leads to dramatic enhancement in the fluorescence emission intensity along with significant occurrence of efficient Frster resonance energy transfer (FRET) from the residue of HIgG to the protein bound guaiacol. From the low value of fluorescence anisotropy (r = 0.06), it is argued that the probe molecule is located in the motionally unrestricted environment of the protein. The alterations of protein’s secondary structure in the presence of guaiacol in aqueous solution were quantitatively calculated by the evidences from FT-IR and CD spectroscopes.

Spectrofluorimetric Study on the Weak Interaction between ATP and Na-4-Tosyl-L-arginine Methyl Ester Hydrochloride

In this paper, some new results on the selective weak interaction between Na-4-tosyl-L-arginine methyl ester hydrochloride （TAME） and adenosine-5＇-triphosphate （ATP） have been reported. Fluorescence spectrophotometry and Fourier transform infrared （FT-IR） spectroscopy were used to investigate this kind of weak interaction. In fluorescence experiments, obvious fluorescence quenching phenomena were observed when TAME was added, which indicated the weak interactions between TAME and ATP. It has been identified by fluorescence titration experiments that TAME exhibited high selectivity to ATP over ADP and AMP. FT-IR spectral results showed that an ATP-TAME adduct was formed. The experimental results indicated that the interaction sites were the guanidinium group of TAME main-chain and the γ-phosphate group of ATP, and the interaction took place through hydrogen bonding and electrostatic force. In addition, the effects of metal ions on the weak interaction between ATP and TAME, or between ATP and analogues of L-arginine were studied.

Infrared spectra study associated with hydrogen impurity in low pressure CVD diamond films

The infrared absorbance peaks at 2 852.4, 2 924.3, 2963.0 and 3 034.9 cm-1 have been observed in diamond films made by the direct current arc discharge plasma chemical vapor deposition. Three former absorbance peaks have been assigned to C-H stretching in SP3 configuration, 3 034.9 cm-1 has been assigned to C-H stretching in SP2 configuration. The

Spectroscopic Studies on the Interaction of Asiatic Acid with Bovine Serum Albumin

Fluorescence spectroscopy, Fourier transform infrared （FT-IR） spectroscopy, circular dichroism （CD） and FT-Raman spectroscopy were employed to analyze the binding of the asiatic acid （AA） to bovine serum albumin （BSA） under simulative physiological conditions. Fluorescence data revealed that the fluorescence quenching of BSA by AA was the result of the formation of BSA-AA complex. The fluorescence quenching mechanism of BSA by AA was a static quenching procedure. According to the Van＇t Hoff equation, the thermodynamic parameters enthalpy change （△H0） and entropy change （△S0） for the reaction were evaluated to be --12.55 kJ·mol^-1 and 67.08 kJomol 1, respectively, indicating that hydrophobic and electrostatic interactions played a major role in stabilizing the complex. The influence of AA on the conformation of BSA has also been analyzed on the basis of FT-IR, CD and FT-Raman spectra.

Crosslinking of PVA Pervaporation Membrane by Maleic Acid

Maleic acid (MA) crosslinked polyvinyl alcohol (PVA) membrane is prepared using a high temperature esterification reaction between PVA and MA in the presence of sulfuric acid as a catalyst. The crosslinking reaction mechanism is investigated using FT IR spectral analysis. The results indicate that maleic acid reacts with hydroxyl groups in PVA to form mono and bis ester in a two step process.

Establishing two-stage interaction between fly ash and NaOH by X-ray and infrared analyses

The interaction of the fly ash and NaOH, in an open reflux hydrothermal system at 100℃, has been explored by several researchers and formation of fly ash zeolites has been confirmed based on the X-ray diffraction analysis of the residues. However, this method does not reveal much about the characteristic transitions （viz. elemental, electro-negativity and cation exchange capa- city） of the residues. In this situation, resorting to Fourier transform-infrared radiation （FT-IR） spectroscopy on the residues obtained from two-stage hydrothermal treatment process, described in this manuscript, appears to be a novel idea to establish transitions in chemical bonds （viz., -Si- OH-AI-, OH-Na, OH-A1-）, crystallinity and cation exchange capacity of these residues. Based on extensive studies, it has been demonstrated that FT-IR spectroscopy is extremely useful for 1） detection of chemical bonds in the residues, 2） evaluation of zeolites in the residues and 3） also establishing the superiority of the two-stage interac- tion of the fly ash with NaOH for synthesizing better fly ash zeolites （viz., Na-P1 and Hydroxysodalte） as compared to those obtained from the conventional single-stage treatment of the fly ash.