Biochemical features and inhibitors of the 1-aminocyclopropane-1-carboxylic acid oxidase isolated from pear fruit

 1-Aminocyclopropane-1-carboxylic acid (ACC) oxidase, the enzyme that catalyzes the final step in ethylene biosynthesis, was recovered from pear (Pyrus communis L. cv. Blanquilla) fruit tissues with maximum activity at pH 6.5. The enzyme eluted as a single hydrophobic protein with an estimated molecular weight of 37.9 kDa in a three-step FPLC chromatographic procedure. The sensitivity of the pear ACC oxidase against a range of chemicals known by their inhibitory action on ethylene biosynthesis in vivo has been studied. Among them, and in contrast to a previous proposal, α-(p-chlorophenoxy)isobutyric acid, a substance possessing antiauxin properties, did not inhibit the in vitro enzyme activity. The significance of the results is discussed in terms of the nature and mechanism of the enzyme reaction. Received: 12 May 1999 / Revised version: 7 July 1999     

Myrtle hydroalcoholic extracts obtained from different selections of Myrtus communis L.

Hydroalcoholic extracts obtained from myrtle berries of five different selections were studied to obtain unique clones. During the typical 40 day maceration period, dry matter, pH, colour, and anthocyanins, were analyzed. Variability among myrtle selections was observed both in fresh berries (yield berries/plant, weight of the berries, number and weight of seeds per berry) and in the hydroalcoholic extract physical–chemical characteristics (dry matter, colour intensity, tint and anthocyanins). Reversed-phase high performance liquid chromatography (RP-HPLC) analysis with photodiode array detection (PDA) was used for anthocyanins characterization in myrtle hydroalcoholic extracts. Anthocyanin qualitative composition was the same in all selections, but varied strongly in its total amount. D was the selection with the characteristics most suitable for industrial use.     

蓖麻LEA基因家族的全基因组鉴定、分类及其进化分析

基于已公布的基因组和EST数据对蓖麻LEA基因家族进行全面鉴定和系统命名,并在此基础上分析了其基因结构、生化特征、进化关系和表达特性。结果显示,蓖麻基因组中存在27个LEA基因,分属于LEA_1、LEA_2、LEA_3、LEA_4、LEA_5、LEA_6、dehydrin和SMP 8个亚家族,它们散布于24条scaffold上,含有0～2个内含子不等,且其中有3个基因存在可变剪接;根据编码蛋白中的Pfam结构域类型及其进化关系,将这些LEA基因依次命名为RcLEA1-1和-2、RcLEA2-1和-2、RcLEA3-1至-3、RcLEA4-1至-7、RcLEA5-1和-2、RcLEA6-1和-2、RcLEA7-1至-5和RcLEA8-1至-4;利用BLAT分析基因表达谱显示,在叶片、花、II/III期胚乳、V/VI期胚乳和种子等组织中,所有RcLEA基因都有表达;启动子分析表明,RcLEA基因的启动子区富含LTRE、ABRE、MYC、MYB和W-box等逆境应答相关顺式作用元件。     

Octane-1,3-diol and its derivatives from pear fruits

 In extracts obtained by liquid-liquid extraction from seven pear (Pyrus communis L.) cultivars, octane-1,3-diol, 5(Z)octene-1,3-diol, methyl 3-hydroxyoctanoate, ethyl 3-hydroxyoctanoate and ethyl 5(Z)-3-hydroxyoctenoate were identified by capillary gas chromatography-mass spectrometry. Evaluation of the absolute configuration was achieved by multidimensional gas chromatography, using a polar achiral column (DB-Wax) and a chiral main column (2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl-β-cyclodextrin/OV 1701). Comparison of retention times of synthesized optically enriched reference compounds with those of isolated diols and hydroxy esters revealed (R)-configurations for the 3-hydroxy derivatives, exhibiting enantiomeric excesses greater than 99%. In addition, (2S, 4R)- and (2R, 4R)-2-methyl-4-pentyl-1,3-dioxane as well as (2S, 4R)- and (2R, 4R)-2-methyl-4-(2′(Z)-pentenyl)-1,3-dioxane, products formed by acetaldehyde and octane-1,3-diol or 5(Z)-octene-1,3-diol, respectively, were detected in pear fruits. Received: 13 February 1997     

新疆特色休闲小食品开口巴旦杏的工艺研究

以巴旦杏为原料,通过适宜的处理,浸泡、漂洗、烘干等方法,获得特色风味的休闲开口巴旦杏产品,应用单因素试验和正交试验对巴旦杏开口最佳工艺参数进行研究。通过开口率和感官评价结果,确定盐酸浓度为20%、在60℃条件下浸泡40min为巴旦杏开口的最佳工艺参数。     

Application of Central Composite Design to evaluate the antilisterial activity of hydro-alcohol berry extract of Myrtus communis L.

The antimicrobial activity of the hydro-alcohol extract of Myrtus communis L. (ME) berries was investigated against six Listeria monocytogenes strains (2 type strains and 4 isolates). Sub-lethal ME concentrations reduced L. monocytogenes counts by at least 2 log cycles. A Central Composite Design was used to investigate the combined effects of sub-lethal concentrations of ME (0.039–0.195 mL/100 mL), NaCl (0–2.0 g/100 mL) and pH (5.0–7.0) on strains growth. ME affected growth parameters, generally extending lag phase length and reducing maximum growth, sometimes with interactive effects with pH. The highest ME concentrations (0.117–0.195 mL/100 mL) combined with the lowest pH values (5.0–6.0) strongly reduced or even inhibited strains growth.     

微波辐照巴旦杏核壳制备活性炭及其吸附性能研究

以巴旦杏核壳为原料,采用微波辐照法制备活性炭。考察了活化条件对活性炭得率和吸附性能的影响。研究结果表明,在活化剂种类、活化剂用量、微波功率和辐照时间4个因素中,微波辐照时间对活性炭质量指标影响最大,延长时间可以提高其产品的得率和吸附性能。巴旦杏核壳基质活性炭的最佳制备工艺：巴旦杏核壳10g,固液比1：3（g：mL）,磷酸质量分数40％、浸溃24h,微波功率640W、活化时间16min。在此条件下制得的活性炭的亚甲基蓝吸附值为231．5mg/g,活性炭得率为56．8％。二级动力学模型能很好的描述巴旦杏核壳活性炭对亚甲基蓝大分子的吸附动力学过程。吸附符合Freundlich吸附等温线方程。     

芦苇叶黄酮类提取物体内体外抗氧化性研究

研究醇提芦苇叶黄酮类提取物的体内体外抗氧化性。通过测定芦苇叶黄酮类提取物对体外大鼠肝组织匀浆、肝线粒体丙二醛（malondialdehyde,MDA）生成量及大鼠红细胞溶血的影响。结果表明：芦苇叶黄酮类提取物在0.5～10 mg/mL范围内能抑制大鼠肝组织匀浆及肝线粒体MDA的生成,抑制大鼠红细胞溶血,具有量效关系,表明芦苇叶黄酮类提取物具有体外抗氧化效果。随着剂量的增加,芦苇叶黄酮类提取物可提高S180荷瘤小鼠血清中谷胱甘肽过氧化物酶（glutathione peroxidase,GSH-Px）和超氧化物歧化酶（superoxide dismutase,SOD）活性,降低MDA含量,从而提高其体内抗氧化活性,当剂量达到300 mg/（kg·d）时,芦苇叶黄酮类提取物与10 mL/（kg·d）的氟尿嘧啶均可促进荷瘤小鼠体内抗氧化能力的提高,且二者间没有显著性差异。