蒸馏-电感耦合等离子体发射光谱法测定葡萄酒中的SO

建立一种自动蒸馏结合电感耦合等离子体发射光谱(ICP-OES)法快速测定葡萄酒中SO2的分析方法。在酸性条件下,先用FOSS Kjeltec8100自动蒸馏仪将葡萄酒样品中的SO2蒸出,然后馏出液用6%(质量分数)过氧化氢(H2O2)溶液吸收,最后采用电感耦合等离子体发射光谱在181. 972 nm波长条件下测定吸收液中的总硫含量,从而计算出葡萄酒中的SO2含量。葡萄酒中SO2在0～0. 032 g/L的范围内具有较好的线性关系,相关系数为0. 999 94。当取样体积为5. 00 m L时,方法检出限为0. 001 1 g/L,定量限为0. 003 5 g/L,加标回收率为76. 0%～95. 3%,相对标准偏差(RSD)9. 8%。该方法具有快速、稳定、高效的优点,可用于葡萄酒中SO2的快速测定。     

HPLC检测三叶青块根中白藜芦醇和白藜芦醇苷含量的研究

目的：建立三叶青地下部分白藜芦醇、白藜芦醇苷以及总黄酮的提取分离和含量测定方法。方法：白藜芦醇提取分离选取溶剂为70%乙醇，白藜芦醇苷的提取分离选取溶剂为40%乙醇。含量测定采用高效液相色谱法，色谱柱选择Agilent ZORBAX SB-C18色谱柱(250 mm×4.6 mm,5μm)，流动相为甲醇-水梯度洗脱，流速为0.8 mL/min，检测波长为304 nm，柱温25℃。结果：白藜芦醇的线性关系方程为Y=113.836X+0.911 5，在0.02～2μg/mL范围内的峰面积与进样浓度线性关系良好(R²=0.997 6)。采用70%乙醇提取三叶青根茎中白藜芦醇的平均含量为0.59μg/g。白藜芦醇苷的线性关系方程为Y=52.515X-0.497 7，在0.02～2μg/mL范围内的峰面积与进样浓度线性关系良好(R²=0.994 4)。采用40%乙醇提取三叶青根茎中白藜芦醇的平均含量为1.76μg/g。结论：建立了三叶青地下部分白藜芦醇、白藜芦醇苷以及总黄酮的提取分离和含量测定方法。建立的高效液相色谱法方法简便，准确，重复性好，可应用于...     

不同发育阶段尖头斜齿鲨肝油脂酸组成的变化

采用气相色谱仪分析测定了不同发育阶段尖头斜齿鲨肝油的脂肪酸组成与含量。在尖头斜齿鲨肝油总脂肪酸组成中 ,饱和脂肪酸占 15 3%～ 34 6 % ,单不饱和脂肪酸占 13 8%～ 2 5 6 % ,多不饱和脂肪酸 (PUFA)占 38 8%～ 6 8 1%。其中 ,最主要的脂肪酸为 16 :0 ,18:0 ,18:1ω9,2 0 :4ω6和 2 2 :6ω3。尖头斜齿鲨肝油脂肪酸组成与个体的发育状况关系密切。雄性尖头斜齿鲨 ,胚胎阶段肝油的脂肪酸主要由16 :0、 16 :1和 18:1(ω9+ω7)组成 ,2 2 :6ω3的含量很低 (3 8± 1 34 ,n =3) ;雄性幼鱼肝油 2 2 :6ω3的含量较胚胎阶段有了显著的提高 (2 7 1± 2 47,n =3) (P <0 0 5 ) ;性成熟个体肝油 2 2 :6ω3的含量达到最高值 (5 1 0± 7 42 ,n =5 ) ,退化期 2 2 :6ω3的含量明显降低 (34 4± 2 40 ,n =3)。雌性尖头斜齿鲨肝油 2 2 :6ω3的含量随着性腺的发育而逐渐增加 ,妊娠早期达到最高值 (49 7± 4 0 4,n =5 ) ,显著高于未成熟期个体 (2 5 7± 0 6 4,n =3)和卵巢发育期个体 (33 3± 3 46 ,n =4) ,妊娠结束期肝油 2 2 :6ω3的含量显著下降 (2 5 6± 8 0 8,n =3) ,提示 2 2 :6ω3在尖头斜齿鲨胚胎的生长发育中可能起了重要作用。     

云南水牛的同期发情、超数排卵和胚胎移植试验

为探讨水牛胚胎移植的效果 ,于 2 0 0 2年对云南水牛进行了胚胎移植试验 :①用国产氯前列烯醇(PG) 0 6mg/头·次处理供、受体水牛的同期发情率和可用率分别为 4 3 33% (13/ 30 )和 16 6 7% (5 / 30 ) ;同期发情率经产水牛高于青年水牛 (P =0 0 86 ) ,杂交水牛高于德宏水牛 (P =0 15 3) ,体重 4 0 1～ 5 30kg水牛显著高于体重 30 0～ 4 0 0kg水牛 (P <0 0 5 ) ;发情明显水牛的可用率极显著高于发情不明显的水牛 (P <0 0 1)。②选用河流型摩拉水牛与沼泽型德宏水牛的杂交一代 5头为供体 ,分进口激素组 (n =2 )和国产激素组 (n =3)进行超数排卵 ,共有 2头获 9枚胚胎 ;进口激素组供体的平均获胚数和可移植胚数分别为 2 0枚和 1 5枚 ,比国产激素组分别多 0 33枚 (P =0 4 5 4 )和 1 17枚 (P =0 2 88)。③所获 4枚可用鲜胚分别移植 3头受体 ,结果 90d的妊娠率为 33 33% ,但最终无一头产犊。试验结果表明使用进口FSH 2 4mg +PG (Lutalyse○R) 35mg和国产FSH 11mg +PG 0 8mg对水牛超数排卵有效 ,同时提示需要足够数量的受体 ,从中选用发情表现明显、黄体发育良好的进行胚胎移植 ,才能取得良好效果。     

葡萄酒中白藜芦醇的分析

采用HPLC测定了17种葡萄酒中白藜芦醇含量。干红葡萄酒中白藜芦醇的含量远高于干白葡萄酒。干红葡萄酒中白藜芦醇的含量与葡萄品种有关,同一葡萄品种的干红葡萄酒中白藜芦醇的含量与产地和工艺有关。     

抗性砧木对赤霞珠葡萄叶片白藜芦醇合成过程及含量的影响

为了明确不同抗性砧木对赤霞珠葡萄叶片白藜芦醇含量及其合成过程中前体物质和相关代谢酶活性的影响,分析不同抗性砧木与白藜芦醇合成的关系,以获得提高接穗品种赤霞珠葡萄叶片白藜芦醇含量的抗性砧木。该研究选择弗卡(Fercal)、5C、140R、3309M、3309C、SO4、抗砧3号(Kangzhen3)、5BB为砧木与赤霞珠(CS)葡萄进行嫁接,以赤霞珠自根苗为对照(CK),采用高效液相色谱技术,测定成熟葡萄叶片白藜芦醇以及合成白藜芦醇前体物质苯丙氨酸、肉桂酸、香豆酸含量,并对合成白藜芦醇相关代谢酶苯丙氨酸解氨酶(PAL)、肉桂酸-4-羟化酶(C4H)、4-香豆-辅酶A连接酶(4CL)、过氧化物酶(POD)以及多酚氧化酶(PPO)的活性进行测定。结果表明:(1)不同砧木均能提高接穗赤霞珠葡萄叶片白藜芦醇含量11%~46%。(2)在各砧穗组合中,CS/140R嫁接苗叶片的白藜芦醇含量最高达到18.24μg/g,其合成白藜芦醇前体物质苯丙氨酸和香豆酸含量也最高,分别达到38.61和1.06μg/g。(3)在各砧穗组合中,白藜芦醇相关代谢酶PAL活性以CS/3309C嫁接苗叶片最高;嫁接苗叶片代谢酶C4H和4CL活性均高于赤霞珠自根苗;POD和PPO活性均以CS/Fercal的接穗赤霞珠叶片最强。研究发现,不同抗性砧木能显著提高赤霞珠葡萄叶片白藜芦醇含量,相关代谢酶C4H活性对葡萄白藜芦醇的合成至关重要,PPO活性与葡萄叶片白藜芦醇合成也密切相关,CS/140R是8个砧穗组合中提高赤霞珠葡萄叶片白藜芦醇含量最具优势的砧穗组合。     

减毒HAV在体外抑制HBV表达HBeAg和HBsAg的实验研究

目的　探索减毒甲型肝炎病毒( HAV) ( H2减毒株)在Hep G2 .2 .15细胞中对乙型肝炎病毒( HBV)表达HBs Ag和HBe Ag的影响。方法　在Hep G2 .2 .15细胞中,加入含3×10 - 2 ( 3×10 4 .5CCID50 / ml) ,3×10 - 3( 3×10 3.5CCID50 / ml)浓度的减毒HAV。按不同疫苗浓度,每4 d换液1次,留取第12和第16天的培养上清液;同时设立对照组。用微粒子酶免分析法检测培养上清液中的HBs Ag和HBe Ag含量。计算减毒HAV在不同浓度,以及不同作用时间长度的条件下,对Hep G2 .2 .15细胞表达HBs Ag和HBe Ag的影响。结果　3×10 - 2 Ampoule/ ml的减毒HAV作用Hep G2 .2 .5细胞12 d后,培养上清液的HBe Ag浓度为( 4 7.2 3±6 .18) S/ CO,低于对照组的( 10 1.15±15 .77) S/ CO,2组比较差异有非常显著性( P<0 .0 1) ;16 d后,上清液HBe Ag含量为( 4 0 .2 7±13.30 ) S/ CO,也显著低于对照组的( 6 5 .85±3.4 6 ) S/ CO( P<0 .0 5 ) ;HBs Ag含量为( 2 .6 8±0 .31) S/ N,低于对照组的( 5 .10±1.2 7)S/ N,差异有显著性( P<0 .0 5 )。而3×10 - 3Ampoule/ ml的减毒HAV作用Hep G2 .2 .15细胞12 d后,培养上清液的HBs Ag浓度与对照组比较有显著性下降( P<0 .0 5 )。结论　一定浓度的减毒HAV可能有直接抑制HBV表达HBs Ag,HBe Ag的作用     

培养基种类对花生毛状根株系生物量和白藜芦醇含量的影响

旨在研究不同培养基对花生毛状根株系生物量和白藜芦醇含量的影响。利用发根农杆菌R1601侵染花生的叶片,诱导毛状根,利用PCR技术检测毛状根。使用5种培养基(1/2MS、MS、MS+500 mg/L羧苄西林钠、B5和N6)分别培养同一个株系的花生毛状根,4周后利用高效液相色谱法(HPLC)测量毛状根生物量和白藜芦醇含量。结果显示,不同培养基对花生毛状根株系生物量的积累有显著差异,1/2MS培养基和MS培养基有利于花生毛状根株系生物量的积累。不同培养基对花生毛状根株系中白藜芦醇的含量有显著差异,B5培养基和N6培养基有利于花生毛状根株系中白藜芦醇的积累。     

葡萄果实成熟期花色苷与白藜芦醇合成相关基因的表达

以酿酒葡萄‘赤霞珠’为试材,采用pH示差法和高效液相色谱(HPLC)法分别测定葡萄成熟期果皮花色苷和白藜芦醇含量,用实时荧光定量PCR检测两者合成途径中相关基因的表达量,分析花色苷含量和白藜芦醇含量与其相关基因表达的关系,以揭示结构基因与调控基因的调控机制,为筛选富含花色苷和白藜芦醇的酿酒葡萄提供理论依据。结果显示:(1)葡萄果皮花色苷含量在花后112d达到最高值(0.77mg/g),反式白藜芦醇含量在花后126d达到最高值(30.87μg/g)。(2)花色苷和白藜芦醇合成途径中,CHSs、CHI、STS、UFGT、MybA1、MybA2基因的表达量除花后98d下调外,其余时间均呈上调表达,而Myb5a则始终呈上调表达。(3)相关分析表明,STS基因表达量与CHS1、CHS2基因表达量呈极显著和显著正相关关系,MybA1、MybA2基因表达量与CHSs、CHI、STS、UFGT基因的表达量呈极显著正相关关系;Myb5a基因表达量与CHS3基因表达量呈极显著正相关关系。研究表明,部分结构基因的表达与花色苷和白藜芦醇的变化不同步,MybA1和MybA2可能调控花色苷合成途径中多个结构基因的表达,花色苷与白藜芦醇的关系并不固定,而是处在动态变化中。     

腌制蔬菜营养成分的测定

分析了腌制蔬菜中的泡菜 ,盐浸渍菜中所含的主要营养成分的种类及其相对含量。结果显示 :泡菜和盐浸渍菜中水分、灰分、粗蛋白、粗脂肪和粗纤维的含量分别为 4 6 1% ,15 95 % ,10 2 8% ,2 19% ,2 3 2 9%和 3 11% ,2 6 49% ,15 19% ,2 42 % ,2 0 0 5 %。其氨基酸总量为 74 5 0 45mg/g ,6 6 4876mg/g ,其中必需氨基酸占 37 46 39%和43 6 76 1%。     

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.     

鸡传染性法氏囊病病毒研究进展

传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).