条件培养液对红豆杉细胞Paclitaxel生产的促进作用

在两步法红豆杉（Taxus chinensis)细胞悬浮培养体系的生产阶段,加入从生长阶段悬浮培养物中制得的条件培养液（conditioned Medium,CM)既能促进细胞的生长,又能提高紫杉醇（paclitaxel)的产率,解决了生产培养时,细胞生长受抑制的问题,特别是,取自生长12天的细胞悬浮培养物的CM按体积分数为25％添加到新鲜生产培养基中时,可使细胞紫杉醇最高产量达28．5mg/L,细胞干重达32．3g/L,分别是对照的2．4倍和2．2倍,对CM中的蔗糖,果糖,NO3－和PO4－3等的含量的进行了分析。     

云南红豆杉细胞的悬浮培养

在云南经豆杉细胞悬浮培养中,适宜的增减基为Ｂ５,接种量为０．５－０．８ｇ干重细胞／１００ｍｌ培养基,２,４－Ｄ浓度为１．０ｍｇ／Ｌ;培养细胞的生长周期约３０ｄ;增减基中较高浓度的蔗糖（４０ｇ／Ｌ）可提高紫杉醇含量;添加的椰子汁（ＣＭ）、酪蛋白氨基酸（ＣＡ）和水解乳蛋白（ＬＨ）３种有机添加剂均能提高培养细胞中紫杉醇的含量,但只有ＣＭ和ＣＡ能促进细胞的生长。于Ｂ５培养基中添国不同浓度的ＮＨ４ＮＯ３对培     

聚乙二醇对东北红豆杉培养细胞的生长及紫杉醇生产的影响

在改良的B5培养基中加入不同浓度的聚乙二醇对东北红豆杉培养细胞进行摇瓶培养,通过不同时期取样并测定细胞鲜,干重及用HPLC测定紫杉醇的含量,发现聚乙二醇对东北红豆杉培养细胞的生长及紫杉醇生产均有明显的促进作用,聚乙二醇为10g/L时,对细胞生长最为有利,细胞培养16d可达到最大生物量,其平均鲜重为28．73g/瓶,增重3．8倍,平均干重为2．14g/瓶,增重3．1倍,聚乙二醇为20g/L,对紫杉醇的生产最有利;细胞培养25d时,培养基中紫杉醇的含量达到最高水平,其含量为2350ug/L,是不加聚乙二醇的11倍。     

高产莪术细胞悬浮系建立及产物前体对挥发油合成的调控研究

研究了高产莪术细胞悬浮系培养的条件及前体物质添加对挥发油合成的调控。结果表明：淡黄色颗粒状愈伤组织是建立高产细胞悬浮系的最佳供试愈伤组织;最佳培养基成分是MS培养基添加葡萄糖与蔗糖各15—30g／L(1：1),氮源为NH4^ 和NO3^-,比例为1：3,总量为80mmol／L;激素组合为6-BA3．0—5．0mg／L、2,4-D1．0mg／L;光下培养10—15天再转入优化条件下的暗培养,可形成稳定的高产细胞悬浮系;其细胞周期中的最大细胞生长量及挥发油含量分别是248g／L和2．28％;前体物质泛酸钙、乙酸铵、乙酸钾的添加均可有效提高培养细胞合成挥发油的百分含量,其中乙酸铵最有效,在指数生长中期添加0．5mmol／L乙酸铵,挥发油的最高含量可达3．11％,产量为8．27g/L,分别是添加前的1.25倍及1.2倍。     

培养基及培养条件对杜仲愈伤组织生长及次生代谢产物含量的影响

以MS、LS、B5、N6、H、Nitsch、White、1／2MS为基本培养基,分别添加0．5mg／L NAA和0．5mg／L BA,分析不同类型培养基对杜仲愈伤组织生长及次生代谢产物含量的影响,并以B5培养基进行光照条件、碳源、蔗糖浓度试验。结果表明：B5培养基不仅有利于愈伤组织生长,也有利于总黄酮的形成,而1／2MS培养基有利于绿原酸的积累;12h／d光照对愈伤组织的生长及绿原酸和总黄酮的合成有明显的促进作用,黑暗不影响愈伤组织的生长,但却抑制绿原酸和总黄酮的形成;3种碳源中,愈伤组织的增长量、绿原酸和总黄酮的含量均以蔗糖为碳源时最高,葡萄糖最低;蔗糖浓度在10～50g／L范围内绿原酸的含量随着糖浓度的升高而升高,40g／L时愈伤组织的增长量和总黄酮的含量最高。     

不同培养条件对悬浮培养茶叶细胞生长及茶氨酸合成的影响

婺源绿茶嫩叶用MS培养基（加IBA 2mg／L,6-BA 4mg／L）进行茶叶愈伤组织悬浮培养,研究了不同培养条件对茶叶细胞悬浮培养过程中细胞生长与茶氨酸合成的影响。结果显示,NH4^＋／NO3^- 1．0／60．0mmol／L、K^＋ 100．0mmol／L、Mg^2＋ 3．0mmol／L、H2PO4^- 3．0mmol／L、蔗糖30．0g／L、水解酪蛋白2．0g/L条件下,茶叶细胞生长量和茶氨酸积累量均达到最高值;提高培养基中蔗糖和水解酪蛋白浓度可使细胞对数生长期和稳定期得到延长,从而有利于茶氮酸积累;H2PO4^-浓度主要影响细胞生长速率和茶氨酸积累速率的同步性,低H2PO4^-浓度环境中茶氨酸积累速率峰值滞后于细胞增长速率峰值,高H2PO4^-浓度环境中早于细胞生长速率峰值出现时间;K^＋和Mg^2＋对细胞生长的影响不明显,但影响细胞茶氨酸合成酶活性,维持适量的K^＋和Mg^2＋有利于茶氨酸积累。添加盐酸乙胺可大幅度提高茶氨酸积累量,并且先加入一定量盐酸乙胺再每天进行少量补充,茶氨酸合成量比一次性加入的效果要好。茶叶细胞生长和茶氨酸积累高峰期在整个培养过程的第19～22天出现,从生产效率考虑,培养周期以19～22天为宜。     

促甲基化因子对西索米星发酵的影响

研究发现,发酵培养基中添加2．0—3．0g,／L蛋氨酸或7．5—10．0mg,／L氯化钴可明显促进西索米星的合成。蛋氨酸的添加时机和添加方式对西索米星产物合成的作用明显不同。在产物合成中前期（30-48h）添加蛋氨酸的效果最佳。当发酵液中蛋氨酸初始浓度为0．656g／L时,与在产物合成初期一次性添加相比,1．5g／L蛋氨酸在产物合成初期、中期和后期均分成3次添加的效果更优,当发酵至91h结束时,发酵液中西索米星浓度可达0．70g／L。     

培养基成分对杜仲愈伤组织生长及次生代谢产物含量的影响

以Bs＋0．5mg／L NAA＋0．5mg／L BA为基本培养基,研究了B5培养基中8种主要无机盐浓度对杜仲愈伤组织生长及绿原酸和总黄酮两种次生代谢产物含量的影响。结果表明：在1000～5000mg／L范围内增加培养基中KNO3的含量有利于愈伤组织生长,B5培养基中当KNO3的浓度达到2／3时,绿原酸和总黄酮含量及产量最高;(NH4)2SO4以4／3原浓度时对愈伤组织生长量、总黄酮含量及产量最高,对绿原酸的含量则是其为原浓度的1／3时最高;MgSO4以2／3浓度对生长量及1／3浓度对绿原酸、总黄酮积累最高;NaH2PO4、CaCl2和MnSO4以原浓度的愈伤组织生长和次生代谢产物合成最好;ZnSO4和FeSO4的原浓度愈伤组织的生长量最大,而1／3浓度的绿原酸和总黄酮含量最高。     

银杏致密细胞团颗粒悬浮培养生产银杏内酯研究

以MS培养基上培养的银杏高产细胞系MH－3为材料,SH培养基为出发培养基,通过优化营养元素和激素配比,建立银杏致密细胞团悬浮培养体系,在培养过程中添加前体异戊二烯和香叶醇有助于提高银杏内酯产量。结果表明：颗粒粒径大小影响银杏内酯的产生,选用0．8SH培养基,添加浓度为3mg/L的2,4－D和2mg/L的6－BA,致密颗粒的平均粒径为3．36mm,细胞中银杏内酯的含量为557μg/g.dw.在培养过程中的10d添加100mg/L的香叶醇,细胞中银杏内酯的含量达到676μg/g.dw。     

诱导子对藏红花悬浮培养细胞生产藏红花色素的影响

考察壳聚糖（chitosan）、壳寡糖（chitosanoligosaccharides,COS）、茉莉酸甲酯（methyljasmonate,MJ）、水杨酸（salicylicacid,SA）和Cu2＋等诱导子对藏红花悬浮培养细胞生长和藏红花色素合成的影响。结果表明：在实验考察浓度范围内,壳寡糖（1～500mg／L）和较低浓度壳聚糖（≤10mrdL）、MJ（≤10μmol／L）、SA（≤10μμmol／L）和Cu2＋（≤1μmoL／L）对细胞生长无显著影响;较高浓度壳聚糖（≥100mg／L）、MJ（≥100μmol／L）、SA（≥100μmoL／L）和cu“（≥10μmoL／L）显著抑制细胞生长。5种诱导子对藏红花色素合成的诱导效果不同,并且与诱导子作用浓度和添加时间有关。MJ诱导效果最好,在细胞培养第0天添加终浓度100仙moL／LMJ,藏红花色素含量（以1克干细胞计）达到28．57mg,比对照提高177．9％。其次是cu“,在细胞培养第4天添加终浓度500μmoL／LCu2＋,色素含量达到19．82mg,比对照提高108．2％。再次是壳聚糖和壳寡糖,在细胞培养第14天分别添加终质量浓度100mg／L壳聚糖和壳寡糖,色素含量分别达到18．33和17．39mg,比对照提高69．1％和69．0％。最后是SA,在细胞培养第14天添加终浓度10μmoL／LSA,色素含量达到14．65mg,比对照提高45．4％。     

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).