不同预处理方式对微波干燥哈密瓜品质的影响

研究不同的漂烫工艺(热水和水蒸汽)对哈密瓜微波干燥品质的影响,对比了不同的漂烫方式、温度和时间对哈密瓜品质的影响。结果表明:采用100℃水蒸汽漂烫2 min效果最佳。在此基础上,研究了柠檬酸和抗坏血酸对哈密瓜护色效果的影响,结果发现,柠檬酸具有较好的护色效果,综合感官评价提升明显,维生素C含量最高,为12.1 mg/100 g。     

锌离子对鲜紫花苜蓿叶的护绿效果及技术优选研究

以鲜苜蓿叶为原料,采用硫酸锌常温处理、硫酸锌和醋酸锌高温处理、蒸馏水漂烫后醋酸锌常温浸泡处理,通过样品的外观颜色、过氧化物酶和多酚氧化酶活性、叶绿素含量综合评价不同处理的护绿效果,以筛选锌离子对鲜苜蓿最佳护绿技术.结果显示:(1) 不同浓度硫酸锌常温浸泡24 h后的紫花苜蓿叶绿素含量均显著高于对照,表现出显著护绿效果,并以0.10%浓度最佳,但处理样室温放置时比未处理对照加速褐变;(2)硫酸锌和醋酸锌的高温护色处理中,以0.05%醋酸锌溶液高温热烫2 min的苜蓿叶绿素含量最高.(3)新鲜紫花苜蓿高温漂烫后再用醋酸锌常温浸泡处理,以0.50%醋酸锌的护色液效果最佳,其样品在4℃冰箱中冷藏7个月后颜色仍为绿色,且叶绿素含量极显著高于对照和其它浓度处理. 研究表明,锌离子对紫花苜蓿叶有显著的护绿效果,并且以95℃蒸馏水热烫2 min后再用0.50%醋酸锌护色液常温浸泡24 h效果最好.     

速冻白芦笋嫩茎的生理生化变化

白芦笋嫩茎经过清洗、护色、烫漂、冷却等处理后,其生理生化发生了变化。清洗的水温５～７℃,白芦笋的多酚氧化酶和过氧化氢酶活性、呼吸强度和粗纤维含量均较低;护色中加入没食子酸丙酯和焦亚硫酸钠起护色和降低这两种酶的作用;烫漂的水温９０～９５℃、ｐＨ５．３～５．５、烫漂１．５～２．０分钟,白芦笋的两种酶钝化,外观乳白略透明,细菌总数、大肠菌群和大肠杆菌都达到卫生要求;烫漂后立即冷却才能降低细胞透性,达到外观的标准。     

速冻白芦笋嫩茎的生理生化变化

白芦笋嫩茎经过清洗、护色、烫漂、冷却等处理后，其生理生化发生了变化。清洗的水湿５－７℃，白芦笋的多酚氧化酶和过氧化氢酶活性、呼吸强度和粗纤维含量均较低。护色中加入没食子酸丙酯和焦亚硫酸钠起护色和降低这两种酶的作用；烫漂的水温９０－９５℃，ｐＨ５．３－５．５、烫漂１．５－２．０分钟，白芦笋的两种酶钝化，外观乳白略透明，细菌总数、大肠菌群和大肠杆菌都达到卫生要求；烫漂立即冷却才能降低细胞透性，达到外观     

香芋粉喷雾干燥工艺研究

我国香芋资源极为丰富,但开发程度远不及山药、甘薯、马铃薯等,所以对香芋加工工艺的研究对其潜在价值的开发具有重要意义。通过单因素试验考察了烫漂温度、烫漂时间、进风温度、进料速度及料液浓度对香芋粉喷雾干燥的影响。试验确定了香芋粉喷雾干燥的最佳工艺为:55℃烫漂10 min、进风温度为180℃、进料速度50 mL/min、料液浓度为0.1 g/mL。     

外源MeJA胁迫对盐生杜氏藻生理生化特性的影响

研究外源茉莉酸甲酯(MeJA)对盐生杜氏藻细胞β-胡萝卜素含量、叶绿素含量、过氧化物酶(POD)活性和超氧化物歧化酶(SOD)活性的影响。结果表明,当外源MeJA浓度为0～100μmol/L时,随着MeJA浓度的升高,β-胡萝卜素和叶绿素含量呈上升趋势,当MeJA浓度为100μmol/L时,盐生杜氏藻β-胡萝卜素和叶绿素含量最高,当MeJA处理浓度大于100μmol/L时,盐生杜氏藻β-胡萝卜素和叶绿素含量逐渐降低。生理生化结果分析表明,外源MeJA处理可提高盐生杜氏藻POD酶和SOD酶活性,随着MeJA浓度的增加,SOD酶活性呈逐渐上升的趋势,POD酶活性呈先上升后下降的趋势,与β-胡萝卜素含量、叶绿素含量的变化趋势基本一致,说明外源MeJA处理可诱导盐生杜氏藻β-胡萝卜素积累可能与叶绿素含量、过氧化物酶(POD)活性和超氧化物歧化酶(SOD)活性有关。     

光系统Ⅱ反应中心CP47/D1/D2/Cyt b-559复合物中色素分子空间取向的线二色光谱研究(英文)

线二色光谱(LD)是研究色素分子在光合膜上空间取向和排布的重要手段。采用低温(1 0 0K)吸收光谱和线二色光谱技术研究光系统Ⅱ核心复合物CP47/D1/D2/Cytb_5 5 9中色素分子的空间取向。结果表明,在光系统Ⅱ核心复合物CP47/D1/D2/Cytb_5 5 9中 6 80nm处有吸收的叶绿素分子Qy 跃迁与光合膜平面平行。β_胡萝卜素分子有两种不同的空间取向,其中在 470和 5 0 5nm处有吸收的 β_胡萝卜素分子(Ⅰ)与光合膜平面近似平行,而在 46 0和 490nm处有吸收的 β_胡萝卜素分子(Ⅱ)与光合膜垂直。光破坏实验显示垂直取向的 β_胡萝卜素分子对强光敏感。6 80nm处吸收的叶绿素分子成分复杂,可能包含有P6 80和核心天线CP47蛋白上的色素分子。     

金花茶鲜叶的杀青技术研究

以金花茶(Camellia nitidissima C.W.Chi)鲜叶为原料,以金花茶叶中主要活性成分叶绿素、茶多酚、黄酮的含量为指标,比较和分析了不同方式(漂烫、蒸汽、微波)对金花茶鲜叶杀青影响,以获得金花茶叶的最佳杀青方式及杀青条件,为金花茶资源的充分开发利用提供参考。研究结果表明:漂烫杀青对金花茶鲜的叶绿素和茶多酚的破坏非常大,不利于活性成分的保留;蒸汽杀青对金花茶鲜叶中黄酮的含量影响较大,与其它2种杀青方式相比含量最低;而采用微波杀青的金花茶叶中各活性成分含量均为最高。其中微波火力为528 W杀青时间90 s处理的金花茶鲜叶的叶绿素含量为0.881 04 mg/g,茶多酚含量为6.9%,黄酮含量为7.12%,可作为金花茶鲜叶的最佳杀青条件。     

超高产杂交稻剑叶衰老过程中的抗氧化性的变化

与对照种汕优63相比,超高产水稻组合培矮64S/E32的剑叶在生长后期具有更高的抗氧化酶(抗坏血酸过氧化物酶APX和谷胱甘肽还原酶GR)活性和小分子抗氧化剂(抗坏血酸Vc、总Vc、还原型谷胱甘肽GSH和β-胡萝卜素)含量,高的清除有机自由基DPPH·能力,更低的膜脂过氧化产物丙二醛含量。这表明培矮64S/E32剑叶在生长后期有强的抗氧化性,这种强抗氧化性与超高产水稻在结实后期剑叶中较慢的叶绿素和蛋白质降解速度相一致。     

类胡萝卜素对亚油酸甲酯氧化的抑制作用

研究溶液中类胡萝卜素对2 ,2’ -偶氮二 (2 ,4短杠二甲基戊腈 ) (AMVN)引发的亚油酸甲酯氧化的抑制作用及色素的消耗变化。表明 β-胡萝卜素 ,叶黄素及胭脂树橙都按依赖于剂量的方式抑制亚油酸甲酯氢过氧化物的形成。41.7×10 -6mol/L的叶黄素及玉米黄质的抑制活性相近 ,高于β-胡萝卜素与胭脂树橙的活性 ,后两者活性近似。在83.3×10 -6mol/L浓度下鸡油菌黄质活性高于叶黄素 ,后者又高于 β-胡萝卜素与胭脂树橙 ,最后两者仍近似。结果表明下列五种类胡萝卜素对亚油酸甲酯氧化的抑制能力为 :鸡油菌黄质>玉米黄质≈叶黄素> β-胡萝卜素≈胭脂树橙。类胡萝卜素在抑制脂质氧化过程中 ,本身逐渐损失消耗 ,4h后在试验所用浓度下最高剩余量不超过20 %。其中鸡油菌黄质与胭脂树橙的消耗速度慢于 β-胡萝卜素与玉米黄质。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV