水杨酸处理诱导采后甜瓜抗坏血酸-还原型谷胱甘肽循环代谢清除过氧化氢的作用及机制

目的：研究抗坏血酸（ascorbic acid，AsA）-还原型谷胱甘肽（reduced glutathione，GSH）循环代谢在水杨酸处理采后甜瓜诱导的过量H2O2清除过程中的作用。方法：用4 mmol/L水杨酸浸泡‘玉金香’厚皮甜瓜10 min，测定处理后果实常温贮藏过程中丙二醛（malondialdehyde，MDA）含量，分析活性氧的积累水平、超氧化物歧化酶（superoxide dismutase，SOD）和过氧化氢酶（catalase，CAT）活力，以及AsA-GSH循环过程相关酶活力及产物和底物含量。结果：水杨酸处理降低了果实MDA含量，第10天处理组MDA含量较对照组降低14.6%；显著提高了果实O2－·的产生速率和H2O2含量（P＜0.05），其中处理后第2天O2－·的产生速率高出同期对照组的1.9 倍，第6天H2O2含量高出对照组果实29.7%；提高了果实SOD活力，但抑制了CAT活力，说明H2O2的清除可能是依赖于除酶促系统外的其他系统。此外，水杨酸处理提高了果实抗坏血酸过氧化物酶、单脱氢抗坏血酸过氧化物酶、脱氢抗坏血酸还原酶和谷胱甘肽还原酶的活力，增加了AsA和氧化型谷胱甘肽的含量，降低了脱氢抗坏血酸和GSH的含量。结论：水杨酸处理诱导了厚皮甜瓜果实的氧爆，抑制了MDA产生，由水杨酸诱导产生的过量H2O2主要依靠AsA-GSH循环系统清除。     

Shelf Life of Minimally Processed Honeydew, Kiwifruit, Papaya, Pineapple and Cantaloupe

This study was to determine the shelf life of minimally processed honeydew melon, kiwifruit, papaya, pineapple, and cantaloupe stored at 4°C. Sensory assessments were carried out at 3-day intervals by highly trained panels until the end of shelf life. Microbiological counts were made immediately after dicing fruit and at the end of shelf life. Results indicated that both the length of shelf life and type of spoilage were related to fruit species. Minimally processed fruit had longer shelf life at 4°than at temperatures recommended for whole fruit when these were greater than 4°C. Spoilage of 4°C-stored kiwifruit, papaya and pineapple pieces was not a consequence of microbial growth.     

Purification and Characterization of an Endoprotease from Melon Fruit

An endoprotease was purified from melon fruit (Cucumis melo L.) by ammonium sulfate precipitation, gel filtration and ion-exchange chromatography using t-butyloxycarbonyl-Ala-Ala-Pro-Leu p-nitroanilide as a substrate. The molecular weight was estimated as 26,000 and isoelectric point pH 9.5. It preferentially hydrolyzed peptide bonds of the carboxyl terminal sides of Leu, Ala, His, Gin, and Am. Activity was strongly inhibited by diisopropyl phosphofluoridate, indicating the serine protease nature of the enzyme. The migration distance on electrophoresis, molecular weight and substrate specificity differed from cucumisin, a known protease from melon. This unusual protease may have potential for special food treatment applications.     

Age-related response of male melon fliesDacus cucurbitae (Diptera: Tephritidae) to cue-lure

Laboratory-reared and wild adults of the melon fly,Dacus cucurbitae Coquillett, were tested for response to cue-lure at various ages. Virgin laboratory (4, 6, 8, 10, 12, and 14 days old) and wild (10, 12, 14, 16, 18, 20, and 22 days old) flies were released into outdoor field cages and trapped from 0800 until 1600 hr. Response of males to cue-lure increased with age and corresponded with sexual maturity for each strain. Females of both strains were relatively nonresponsive to cue-lure. Failure to eradicate in past male annihilation programs againstD. cucurbitae may be explained in part by the fact that only older males, which may have already mated with gravid females, respond to cue-lure.     

Enzyme catalyzed durable and authentic oriental lacquer: a natural microgel-printable coating by polysaccharide–glycoprotein–phenolic lipid complexes

The chemistry and technology of oriental lacquer, proof of long-term durability by a laboratory test, and morphological features of the closely packed shell (polysaccharides–glycoproteins)–core (polymerized urushiol) microgel particles, which are chiefly responsible for degradation due to efflorescence outdoors, are described. The dimerization mechanism of urushiol was demonstrated by separation of over 20 urushiol dimer derivatives. Physiological dimerization of urushiol in the lacquer is very much influenced by the humidity in drying, and the interaction of semiquinone radicals with metal ions, hydrophilic polysaccharides and amphipathic glycoproteins contained in the lacquer. A mechanism for renewable oriental lacquer is proposed, involving harmony of technology and nature within the lacquer tree plantations in south-east Asia. A brief review of studies of lacquer chemistry and synthetic coatings is given.     

采前水杨酸处理对哈密瓜果实防御酶的诱导

采用1.0、2.0、3.0 mmol/L水杨酸分别在"蜜农9号"哈密瓜开花前1周、幼果期(花后2周)、果实迅速膨大期(花后3周)和网纹形成期(花后4周)对植株进行4次喷洒.依次在幼果期、膨大期、网纹形成期和成熟期进行取样.分析不同浓度水杨酸处理后果实体内3种防御性酶活性的变化.结果表明:采前1.0、2.0、3.0 mmol/L水杨酸处理均能有效地提高哈密瓜果实中过氧化物酶(POD)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)活性,尤其以2.0 mmol/L水杨酸处理酶活性增加最为显著.     

Chinese melon (Momordica charantia L.) seed: Composition and potential use

Chinese melon (Momordica charantia L.), also known as bitter gourd, is a tropical crop, grown throughout Asian countries for use as food and medicinals. In 1993, four cultivars of Chinese melon were grown in Mississippi and the seeds were collected. Oil contents of the seeds ranged from 41 to 45% and the oils contained 63–68% eleostearic acid and 22–27% stearic acid. Industrially important tung oil, a “fast-drying oil” used in paints and varnishes, contains 90% eleostearic and 2–3% stearic acid. The ratio of stearic to eleostearic in Chinese melon seed oil is ten times greater than that in tung oil. The higher ratio should reduce the rate of drying and crosslinking and could be advantageous in the paint industry. The defatted meals contained 52–61% protein and would be a good source of methionine.     

王蒙的意识流小说创作

新时期初,王蒙在小说创作中对西方现代主义的"意识流"手法进行了大胆尝试,他的"意识流"小说既具有现代派小说注重心理描写、反传统、反常规的基本特点,又具有以逻辑顺序为主线,以典型环境和典型事件展现人物形象等"东方式"的特色.     

甜瓜藤有效部位抗肿瘤作用的动物实验研究

目的：探讨甜瓜藤有效部位（MVEP，melon vines effective part．）抗肿瘤作用并初步探讨其抗肿瘤机制，为其临床应用提供实验室依据。方法：将接种肿瘤后的小鼠随机分为5组，每组10只小鼠，雌雄各半，给药10d，停药后24h处死动物，称鼠体重，剥离小鼠右腋下皮下组织，摘出肿瘤，称瘤重，测定生化指标。结果：对肉瘤（S180）、肝癌（Hep）、胃癌（MFC）细胞荷瘤小鼠肿瘤生长具有明显的抑瘤作用，其中对S。so作用显著，较低剂量即可显示明显作用；延长S180荷瘤鼠生存时间；同时可增加吞噬指数a、廓清指数k及胸腺系数：对体外淋巴细胞转化功能亦有增强作用。结论：MVEP具有明显抗肿瘤活性。     

几种特色瓜的腌制技术(上)

为增加腌制瓜的品种，该文介绍了4种腌制瓜的腌制方法。蒜泥乳瓜是将乳黄瓜用白矾、石灰浸洗后，经腌制、压卤、加蒜泥拌匀后入缸加蜜酒和香醋浸渍而成，呈深绿色，质地脆嫩，香甜可口，有酯香和蒜香，风味独特。香酸甜香瓜是将香瓜洗净后，经腌渍、起缸、烫漂、曝晒、糖醋渍和翻缸等工序制成的，色泽黄亮、香气扑鼻、酸甜清脆。豆豉酱片瓜是将青皮小菜瓜去籽后，经腌制、去卤、加豆豉酱制等工序制成，呈红褐色、有光泽，口味鲜美、脆嫩，具有豆豉香气。糟稍瓜是将稍瓜洗净后，经刺眼、擦盐、曝晒、入缸糟渍、起缸沥卤、加配抖入坛糟涪和威熟等工序制戍的．呈橙黄龟、半透明状。口感鲜甜香脆。