α-亚麻酸-阿霉素前药的合成以及抗肿瘤活性研究

目的:合成具有酸敏特性的α-亚麻酸-阿霉素前体药物,并观察其抗肿瘤活性以及对肿瘤细胞的靶向性。方法:以BocNHNH2、α-亚麻酸、阿霉素为主要反应原料,先后合成Boc保护的α-亚麻酰肼、α-亚麻酰肼和α-亚麻酸-阿霉素腙键连接物,采用核磁共振、质谱等方法鉴定其结构;采用LC/MS方法研究连接物在不同pH介质中的药物释放行为;采用MTT法观察连接物对人肝癌细胞HepG2、乳腺癌细胞MDA-MB-231和MCF-7细胞的毒性作用。结果:在1-乙基-(3-二甲基氨基丙基)碳酰二亚胺盐酸盐(EDC·HCl)的催化作用下,合成了α-亚麻酸-阿霉素前体药物,波谱分析提示为目标产物。通过在体外酸性条件下水解连接物,我们发现该连接物具有显著的pH值敏感性。同时在体外细胞毒性实验中,我们发现相比于游离阿霉素,该合成连接物α-亚麻酸-阿霉素对HepG2、MDA-MB-231和MCF-7三种肿瘤细胞具有更强的细胞毒性,而且细胞毒性作用可被外源性α-亚麻酸抑制。结论:α-亚麻酸-阿霉素连接物能经α-亚麻酸受体介导靶向于α-亚麻酸受体丰富的肿瘤细胞,是一种潜在的新型抗肿瘤药物。     

重组人白蛋白干扰素α-2b融合蛋白的稳定性研究

研究重组人白蛋白干扰素α-2b融合蛋白(rHSA-IFNα-2b)的稳定性.以抗病毒活性和纯度为主要检测指标,考察rHSA-IFNα-2b的热稳定性,酸碱稳定性以及冻融耐受性.rHSA-IFNα-2b在37℃、55℃下放置5h后生物学活性无明显降低,60℃水浴lh即可见活性降低了约40%;pH值(分别为2、3、9)改变时,生物学活性未发生明显变化;rHSA-IFNα-2b反复冻融后聚合体逐渐增加,冻融4次后聚合体含量达到17.91%,但生物学活性无明显降低.重组人白蛋白干扰素α-2b融合蛋白对热、酸碱变化稳定,但不宜冻融.     

线粒体靶向TPP-DOX连接物的制备及其逆转肿瘤耐药活性研究

目的:阿霉素(DOX)是常用的抗肿瘤药物,但是它的毒副作用大,而且肿瘤细胞易对DOX产生耐药,限制了其临床应用。本研究利用肿瘤细胞线粒体跨膜电位较高的特性,将亲脂性阳离子(3-丙羧基)三苯基溴化膦(TPP)与DOX相连接制备具有线粒体靶向功能的TPP-DOX,以期达到逆转肿瘤细胞耐药的目的。方法:以DOX、TPP为原料,合成TPP-DOX,通过核磁、质谱等方法进行结构鉴定。采用MTT方法研究TPP-DOX对KB细胞、A549细胞及耐DOX肿瘤细胞MDA-MB-231/ADR的体外抗肿瘤活性。采用激光共聚焦显微镜观察TPP-DOX在肿瘤细胞内的分布。结果:TPP-DOX对KB细胞和A549细胞的毒性低于DOX,TPP-DOX对耐DOX肿瘤细胞MDA-MB-231/ADR的毒性明显大于DOX。激光共聚焦显示TPP-DOX分布于细胞核和线粒体中。结论:TPP-DOX具有线粒体靶向特性,可有效逆转肿瘤耐药,有进一步研究的价值。     

叶酸-阿霉素连接物的制备及其抗肿瘤活性研究

目的:合成具有酸敏特性的叶酸-氨基己酸-阿霉素连接物,并观察其抗肿瘤活性以及对肿瘤细胞的靶向性.方法:首先将叶酸与氨基己酸连接,然后利用腙键与阿霉素连接,采用核磁共振、质谱等方法鉴定其结构;采用MTT法观察连接物对叶酸受体袁达阳性的口腔表皮样癌细胞KB细胞及叶酸受体表达阴性肺癌A549细胞的毒性作用.结果:在氮羟基琥珀酰亚胺和二环己基碳二亚胺的催化作用下,合成了叶酸-氨基己酸-阿霉素连接物,波谱分析提示为目标产物.与游离阿霉素相比,连接物对KB细胞具有更强的细胞毒性,而且细胞毒性作用可被外源性叶酸抑制;而连接物对A549细胞的毒性弱于游离阿霉素,而且外源性游离叶酸对其细胞毒性没有显著影响.结论:叶酸-氨基己酸-阿霉素连接物能经叶酸受体介导靶向于叶酸受体丰富的肿瘤细胞,是一种潜在的新型抗肿瘤药物.     

叶酸-阿霉素连接物的制备及其抗肿瘤活性研究

目的:合成具有酸敏特性的叶酸-氨基己酸-阿霉素连接物,并观察其抗肿瘤活性以及对肿瘤细胞的靶向性。方法:首先将叶酸与氨基己酸连接,然后利用腙键与阿霉素连接,采用核磁共振、质谱等方法鉴定其结构;采用MTT法观察连接物对叶酸受体表达阳性的口腔表皮样癌细胞KB细胞及叶酸受体表达阴性肺癌A549细胞的毒性作用。结果:在氮羟基琥珀酰亚胺和二环己基碳二亚胺的催化作用下,合成了叶酸-氨基己酸-阿霉素连接物,波谱分析提示为目标产物。与游离阿霉素相比,连接物对KB细胞具有更强的细胞毒性,而且细胞毒性作用可被外源性叶酸抑制;而连接物对A549细胞的毒性弱于游离阿霉素,而且外源性游离叶酸对其细胞毒性没有显著影响。结论:叶酸-氨基己酸-阿霉素连接物能经叶酸受体介导靶向于叶酸受体丰富的肿瘤细胞,是一种潜在的新型抗肿瘤药物。     

进口薯片中脂肪酸成分的检测与分析

目的：对11个进口品牌薯片中的脂肪酸进行测定比较,为消费者选购薯片提供营养学参考。方法：采集多个批次的薯片进行混合缩分,利用气相色谱-质谱联用技术（GC-MS）对薯片中的脂肪酸进行定性定量分析,对薯片中的主要脂肪酸的百分含量进行对比分析。结果：11个薯片样品的总脂肪含量为204~344mg/g,薯片中含有丁酸、辛酸、癸酸等24种脂肪酸,以棕榈油为原料加工的薯片,其棕榈酸、油酸、亚油酸百分含量均值为39.6%、39.5%、9.3%,而以葵花籽油为原料加工的薯片,其相应脂肪酸百分含量均值为7.0%、23.4%、59.5%。结论：薯片中的脂肪酸组成主要受加工所用油料影响。同时加工过程中油料使用时间过长或加热温度过高也会使其不饱和脂肪酸含量减少。     

糖化变温的不同处理对黑蒜品质的影响

以大蒜为原料,在高温高湿环境下,采用由5%食盐水浸泡6 h,-80℃冷冻6 h,45℃恒湿酶活1 d,恒湿变温糖化,45℃干燥5 d等工艺过程组成的黑蒜加工新工艺,以感官评价与理化指标检测相结合的方法,开展了黑蒜加工糖化变温的不同处理条件对黑蒜色泽、气味、口感、还原糖、总酚和还原力的影响研究。结果表明:糖化变温参数变温前80℃4 d,变温后65℃1 d为最佳。所加工的黑蒜为黑褐色,无辛辣味、酸甜适口,软糯有弹性;总糖、还原糖和总酚含量分别为69. 06%、32. 14%和0. 67%,且具有较好还原力。     

山楂叶螨滞育的初步研究

本文采用海绵水盘法研究了山楂叶螨Tetranychus viennensis Zacher的滞育与温度、光照和寄主营养等环境因子的关系。结果表明21℃下,临界光周期为12 h 32 min,光敏感螨态为幼螨至第二若螨之间的连续两个螨态,单独一个发育阶段对短光照不敏感或仅有微弱的感应。在相同寄主（梨树）叶片上,病叶和老叶诱导的滞育率比嫩叶高,分别为69.7%、55.3%和20%。相同叶片,短光照(12.5 h/d)条件下随螨密度的增大滞育率升高。相同短光照下,低温促进滞育,在15℃、18℃和21℃下滞育率分别为100%、93.1%和66.7%;高温（24℃）抑制滞育,滞育率仅为13.3%;温度为27℃时不滞育。     

芽孢杆菌β-甘露聚糖酶基因的克隆及表达

从新疆极端干燥环境土壤样品中筛选到具有高β-甘露聚糖酶活性的芽孢杆菌(Bacillus sp.MX).运用PCR技术从该菌基因组中克隆得到β-甘露聚糖酶基因,连接到表达载体pET-28a上.在大肠杆菌BL21中高效表达的基因产物经亲和层析纯化,SDS-PAGE凝胶电泳分析显示该蛋白的相对分子质量为41 kD.酶学性质分析表明该酶在25～95℃,pH3.0～9.6范围内均具有酶活.最适作用温度55℃和pH值5.0,酶比活力为4 572 U/mg.在最适pH 5.0,高温85℃和95℃分别处理10min后,该酶相对酶活力仍保持51%和34%,显示β-甘露聚糖酶具有较好的耐酸性和热稳定性.     

生理成熟期高温高湿胁迫对春大豆种子活力、主要营养成分及种皮结构的影响

采用盆栽方式,研究了宁镇1号和湘豆3号2个春大豆品种在种子生理成熟期受到高温高湿胁迫[(40±2)℃/(30±2)℃、相对湿度(95±5)%/(70±5)%、10 h/14 h(昼/夜)]后种子活力指标、主要营养成分及种皮解剖结构的变化.结果表明:生理成熟期植株受到高温高湿胁迫后,2个春大豆品种种子生活力、发芽势、发芽率以及脱氢酶、酸性磷酸酶活性呈下降趋势,种子细胞膜透性增大,浸种液中的H+、可溶性糖和亮氨酸含量上升,种子中的脂肪和蛋白含量无规律性变化,种皮与种脐解剖结构发生改变;短期的高温高湿胁迫(5 h)对春大豆种子活力的影响不明显,胁迫时间超过48 h,种子活力相关指标急剧降低;湘豆3号较耐高温高湿胁迫,表现为发芽势和相关酶活性下降及浸种液外渗物含量增加的幅度小,种皮致密、厚实,种脐结构完整等特征.     

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).