鳗鱼皮胶原蛋白水解物对结肠炎的改善作用

溃疡性结肠炎(UC)是一种特发性肠道疾病,发病率不断上升,且治疗药物都存在不同程度的副作用。研究发现胶原蛋白肽可缓解UC症状,并且安全、健康。然而,目前研究主要局限于UC的预防作用,缺少对其治疗作用的研究。鳗鱼皮富含胶原蛋白,而鳗鱼头一般在加工中被丢弃,造成资源浪费,目前缺少对鳗鱼皮胶原蛋白水解物的研究。本研究尝试利用鳗鱼头中的鱼皮提取胶原蛋白并进行水解,希望得到对UC具有治疗作用的鳗鱼皮胶原蛋白水解物(CH),提高鳗鱼加工副产物的利用价值。研究发现鳗鱼皮所含胶原蛋白丰富,占鱼皮湿重的27.87%,纯度较高且主要为Ⅰ型胶原蛋白,可作为胶原蛋白的优质来源。对胶原蛋白进行酶解,得到具有抗氧化活性的CH,并给药UC模型小鼠,结果显示:与阳性对照和模型组相比,CH可以安全健康地降低UC模型小鼠的DAI评分至0,并改善结肠状态;结肠组织病理切片表明CH可以恢复黏膜上皮完整性,减轻炎性细胞浸润;结肠组织氧化应激指标表明CH可以降低结肠组织MDA含量(0.75 nmol/mg pro)和MPO活性(0.11 U/g tissue),并通过提高GSH含量(22.92 umol/g pro)和SOD(693.61 U/g pro)、CAT(1.69 U/g pro)、GPx(141.29 U/g pro)3种抗氧化酶活性来提高结肠组织抗氧化能力,降低氧化应激水平,从而治疗UC。     

An Additional Insight into the Correlation between the Distribution Ratios and the Aqueous Acidity of the TODGA System

Abstract

Extraction of Eu(III) and Am(III) from HNO₃ into the organic solvents using N,N,N′,N′‐tetraoctyl‐diglycolamide (TODGA) was investigated in order to study the detailed extraction reaction. The chemical species: 1:2 for metal:TODGA complex is present in polar diluents. On the other hand, the metal complexes need three or more TODGA molecules to remain stable in non‐polar diluents. The HNO₃ concentration dependence on the distribution ratio suggests that HNO₃ participates in the metal extraction. Infrared spectra indicate that the carbonyl oxygen coordinates with Eu(III), and luminescence lifetimes suggest that there are no water molecules in the inner coordination sphere of the extracted Eu‐complex.     

Effects of freezing pretreatment and hygroscopicity of fluidizing particles on drying characteristics of carrots in fluidized bed under reduced pressure

Abstract

A method for low-temperature drying with high drying rate was developed for heat-sensitive foods and agricultural products. A freezing pretreatment was combined with fluidized bed drying under reduced pressure. Cylindrical carrot samples were frozen and then placed without thawing in a fluidized bed of hygroscopic porous silica gel particles that adsorbed water from the sample during the drying process. The effects of the freezing pretreatment and hygroscopicity of fluidizing particles on the drying characteristics of carrots were examined. A higher drying rate was achieved when carrots samples were subjected to freezing pretreatment than without it. At 12?kPa, the volume change was smaller in carrots subjected to freezing pretreatment than in untreated samples. A larger amount of water was absorbed during rehydration by carrots dried at 12?kPa than at 101?kPa within 120?min. The properties of dried carrots were affected not only by freezing pretreatment but also by the pressure applied during the drying process.     

Infrared study of catalytic reduction of lean NOx with alcohols over alumina-supported silver catalyst

Two intense IR absorption bands due to surface isocyanate (-NCO) species have been observed at 2262 and 2232 cm^–1 when an alumina-supported silver catalyst is exposed to a mixture of NO, O₂ and ethanol at 150°C and subsequently heated to > 300°C in vacuum. The intensity of the isocyanate band is hardly affected by the water existing in the mixture. Methanol is less reactive than ethanol for the formation of isocyanate species. The reaction mechanism of catalytic reduction of lean NOx with alcohols is discussed based on these IR spectroscopic findings.     

利用普通小球藻Chlorella vulgaris C9-JN2010处理氨基酸工业废水的研究

用普通小球藻Chlorella vulgaris C9-JN2010处理氨基酸工业废水,实现废水无害化利用。在微型鼓泡式光反应器中,(25±1)℃,pH(6.5±0.5),0.1 vvm空气流速,4 000 lux,16 h:8 h光暗比条件下,分别考察小球藻在体积分数为20%、40%、60%、80%及100%的氨基酸废水中培养生物量变化及TN、TP、COD的去除率。结果表明,体积分数40%氨基酸废水处理效果最好,停留时间3～4 d,藻细胞干重、比生长速率和最大生产强度分别为0.731 g/L、0.565 d-1、0.243 g/(L.d);废水中TN、TP及COD的去除率分别为92.0%、98.0%及80.0%,对应去除强度分别为30.7、3.28、133.3mg/(L.d)。利用小球藻可以较彻底的去除氨基酸废水中氮、磷及COD等营养,达到污水处理效果。     

Combinatorial Measurement of CDKN1A/p21 and KIF20A Expression for Discrimination of DNA Damage-Induced Clastogenicity

In vitro mammalian cytogenetic tests detect chromosomal aberrations and are used for testing the genotoxicity of compounds. This study aimed to identify a supportive genomic biomarker could minimize the risk of misjudgments and aid appropriate decision making in genotoxicity testing. Human lymphoblastoid TK6 cells were treated with each of six DNA damage-inducing genotoxins (clastogens) or two genotoxins that do not cause DNA damage. Cells were exposed to each compound for 4 h, and gene expression was comprehensively examined using Affymetrix U133A microarrays. Toxicogenomic analysis revealed characteristic alterations in the expression of genes included in cyclin-dependent kinase inhibitor 1A (CDKN1A/p21)-centered network. The majority of genes included in this network were upregulated on treatment with DNA damage-inducing clastogens. The network, however, also included kinesin family member 20A (KIF20A) downregulated by treatment with all the DNA damage-inducing clastogens. Downregulation of KIF20A expression was successfully confirmed using additional DNA damage-inducing clastogens. Our analysis also demonstrated that nucleic acid constituents falsely downregulated the expression of KIF20A, possibly via p16 activation, independently of the CDKN1A signaling pathway. Our results indicate the potential of KIF20A as a supportive biomarker for clastogenicity judgment and possible mechanisms involved in KIF20A downregulation in DNA damage and non-DNA damage signaling networks.     

Diffusion process of amino acids in polymer supports for solid‐phase peptide synthesis as studied by pulsed‐field‐gradient spin‐echo proton nuclear magnetic resonance

The diffusion coefficient (D) values of tert‐butyloxycarbonyl‐glycine, tert‐butyloxycarbonyl‐L ‐tryptophan, tert‐butyloxycarbonyl‐L ‐phenylalanine (Boc‐Phe), and 9‐fluorenylmethoxycarbonyl‐L ‐phenylalanine in Merrifield polystyrene (MPS) gels, poly(ethylene glycol)‐grafted polystyrene (PEG–PS) gels, and crosslinked ethoxylate acrylate (CLEAR) gels, as used in solid‐phase peptide synthesis, were determined by the pulsed‐field‐gradient spin‐echo ¹H‐NMR method. From these experimental results, it was found that the amino acids in MPS gels, PEG–PS gels, and CLEAR gels with N,N‐dimethylformamide‐d₇ (DMF‐d₇) as a solvent had multidiffusion components within a measurement timescale of 10 ms. The D value of Boc‐Phe in polystyrene gels (1% divinylbenzene crosslinked) with tetrahydrofuran‐d₈ was much larger than that in the same gels with DMF‐d₇. Furthermore, the required time in which an amino acid transferred from a reactive site to a reactive site was estimated, within which the solvents and amino acids in the polymer supports diffused in the swollen beads.© 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 413–421, 2003     

Oxidation kinetics for <Emphasis Type="Italic">cis</Emphasis>-9,<Emphasis Type="Italic">trans</Emphasis>-11 and <Emphasis Type="Italic">trans</Emphasis>-10,<Emphasis Type="Italic">cis</Emphasis>-12 isomers of CLA

The autoxidation processes of the cis-9,trans-11 (c9,t11) and trans-10,cis-12 (t10,c12) isomers of CLA were separately observed at ca. 0% RH and different temperatures. The t10,c12 CLA oxidized faster than the c9,t11 isomer at all tested temperatures. The first half of the oxidation process of t10,c12 CLA obeyed an autocatalytic-type rate expression, but the latter half followed first-order kinetics. On the other hand, the entire oxidation process of c9,t11 CLA could be expressed by the autocatalytic-type rate expression. The apparent activation energies and frequency factors for the autoxidation of the isomers were estimated from the rate constants obtained at various temperatures based on the Arrhenius equation. The apparent activation energies for the CLA isomers were greater than those for the nonconjugated n−6 and n−3 PUFA or their esters. However, the enthalpyentropy compensation held during the autoxidation of both the CLA and PUFA. This suggested that the autoxidation mechanisms for the CLA and PUFA were essentially the same.     

Regiospecific analysis by ethanolysis of oil with immobilized <Emphasis Type="Italic">Candida antarctica</Emphasis> lipase

A mixture of oil/ethanol (1∶3, w/w) was shaken at 30°C with 4% immobilized Candida antarctica lipase by weight of the reaction mixture. The reaction regiospecifically converted FA at the 1- and 3-positions to FA ethyl esters, and the lipase acted on C₁₄−C₂₄ FA to a similar degree. The content of 2-MAG reached a maximum after 4 h; the content was 28–29 mol% based on the total amount of FA in the reaction mixture at 59–69% ethanolysis. Only 2-MAG were present in the reaction mixture during the first 4 h, and 1(3)-MAG were detected after 7 h. After removal of ethanol from the 4-h reaction mixture by evaporation, 2-MAG were fractionated by silica gel column chromatography. The contents of FA in the 2-MAG obtained by ethanolysis of several oils coincided well with FA compositions at the 2-position, which was analyzed by Grignard degradation. It was shown that ethanolysis of oil with C. antarctica lipase can be applied to analysis of FA composition at the 2-position in TAG.     

Preparation of regioisomers of structured TAG consisting of one mole of CLA and two moles of caprylic acid

TAG (MLM) with medium-chain FA (MCFA) at the 1,3-positions and long-chain FA (LCFA) at the 2-position, and TAG (LMM) with LCFA at the 1(3)-position and MCFA at 2,3(1)-positions are a pair of TAG regioisomers. Large-scale preparation of the two TAG regioisomers was attempted. A commercially available FFA mixture (FFA-CLA) containing 9-cis, 11-trans (9c, 11t)- and 10t,12c-CLA was selected as LCFA, and caprylic acid (C₈FA) was selected as MCFA. The MLM isomer was synthesized by acidolysis of acyglycerols (AG) containing two CLA isomers with C₈FA: A mixture of AG-CLA/C₈ FA (1∶10, mol/mol) and 4 wt% immobilized Rhizomucor miehei lipase was agitated at 30°C for 72 h. The ratio of MLM to total AG was 51.1 wt%. Meanwhile, LMM isomer was synthesized by acidolysis of tricaprylin with FFA-CLA: A mixture of tricaprylin/FFA-CLA (1∶2, mol/mol) and 4 wt% immobilized R. miehei lipase was agitated at 30°C for 24 h. The ratio of LMM to total AG was 51.8 wt%. MLM and LMM were purified from 1,968 and 813 g reaction mixtures by stepwise short-path distillation, respectively. Consequently, MLM was purified to 92.3% with 49.1% recovery, and LMM was purified to 93.2% with 52.3% recovery. Regiospecific analyses of MLM and LMM indicated that the 2-positions of MLM and LMM were 95.1 mol% LCFA and 98.3 mol% C₈ FA, respectively. The results showed that a process comprising lipase reaction and short-path distillation is effective for large-scale preparation of high-purity regiospecific TAG isomers.