一种高纯度,无SDS的重组人白细胞介素2制备方法

由Ｅ．ｃｏｌｉ表达的重组白细胞介素２（ｒＩＬ－２）以包含体形式存在于工程菌胞浆中,经超声破碎等步骤处理提取包合体,用盐酸胍（ＧｕＨＣｌ）将其溶解后经ＳｅｐｈａｃｒｙｌＳ－２００分子筛提纯,复性后再用单克隆抗体柱进行亲和层析纯化,结果可使ｒＩＬ－２纯度达９９％以上,平均比活性为１．０×１０７Ｕ／ｍｇ蛋白左右,产品不含ＳＤＳ,残余鼠ＩｇＧ含量测定符合生物制品规程要求。     

反相高压液相色谱折叠重组人白细胞介素-2

重组人白细胞介素－２（ｒｈＩＬ－２）基因表达产物在大肠杆菌中以不溶性包涵体形式存在,经过菌体发酵和收集、超声破菌、包涵体抽提、稀释透析初步复性、反相高压液相色谱纯化,终产物纯度大于９９％。反相高压液相色谱不仅可以纯化ｒｈＩＬ－２,且使产物的总活性提高７．９－９倍,比活性提高１４￣１８倍,达到１．５×１０＾７ｕ／ｍｇ蛋白质,蛋白得率为５０％￣５６％。结果表明,反相高压液相色谱具有纯化和显提高ｒｈＨ     

中麻黄悬浮培养体系的建立

本文用中麻黄无菌苗为外植体,其切段培养在附加２ｍｇ／Ｌ２,４－Ｄ和０．５ｍｇ／Ｌ　６　ＢＡ的ＭＳ培养基上,全部脱分化形成白色疏松愈伤组织。愈伤组织继代培养于ＭＳ＋０．５ｍｇ／Ｌ２,４－Ｄ＋０．２ｍｇ／Ｌ６ＢＡ＋０．２ｍｇ／Ｌ　ＮＡＡ＋４％蔗糖的培养某上。以继代培养愈伤组织为材料进行悬浮培养,培养基为附加０．２ｍｇ／Ｌ２,４－Ｄ＋０．１ｍｇ／Ｌ６ＢＡ＋０．１ｍｇ／ＬＮＡＡ＋２％蔗糖的ＭＳ液体培养基,得到分散性好,细胞形状接近圆形,细胞大小均一,细胞团多由２－３０个细胞组成的悬浮培养体系。第三代悬浮培养细胞增长率为０．３５ｇ·ｆｗ／２０ｍｌ·ｄ,细胞有丝分裂指数为１１．２％。条件培养和高密度接种可缩短延迟期,条件培养不能提高分裂指数,１ｇ／１０ｍｌ接种密度可使分裂指数提高至２１．２％。     

重组人白细胞介素－2在离子色谱分离时的复性

采用ＨＰＩＥＣ应用ＣＭ交换柱分离纯化Ｅ．ｃｏｌｉ工程菌表达的ｒＩＬ－２,与空气氧化复性相比较,又有１倍以上的变性ｒＩＬ－２在色谱过程中得到复性,且溶液ｐＨ影响ｒＩＬ－２的复性和纯化效果：ｐＨ７．０时ｒＩＬ－２复性率高于ｐＨ８．０时,但纯度明显低于ｐＨ８．０时分离的ｒＩＬ－２．     

重组人白细胞介素—2在离子色谱分离时的复性

采用ＨＰＩＥＣ应用ＣＭ交换柱分离纯化Ｅ．ｃｏｌｉ工程菌表达的ｒＩＬ－２,与空气氧化复性相比较,又有１倍以上的变性ｒＩＬ－２在色谱过程中得到复性,且溶液ｐＨ影响ｒＩＬ－２的复性和纯化效果：ｐＨ７．０时ｒＩＬ－２复性率高于ｐＨ８．０时,但纯度明显低于ｐＨ８．０时分离的ｒＩＬ－２。     

大叶紫花苜蓿愈伤组织原生质体再生植株

大叶紫花苜蓿下胚轴诱导的愈伤组织在继代培养基上生长快速,易于分散。继代第１２ｄ的愈伤组织原生质体的得率为６．５×１０７／ｇ鲜重。原生质体培养基为ＳＨ基本培养基,含有１．０ｍｇ／Ｌ２,４－０、０．５ｍｇ／ＬＢＡ、２．０ｇ／ＬＣＨ、２％蔗糖、６％葡萄糖、５ｍｍｏｌ／ＬＭＥＳ,培养密度为１．０×１０５／ｍＬ。培养至第１２ｄ时的原生质体再生细胞植板率为３．７％。由原生质体形成的小愈伤组织在含２．０ｍｇ／Ｌ２,４－Ｄ的ＭＳ固体培养基上大量增殖。增殖的愈伤组织转移至２．０ｍｇ／Ｌ２－ｉｐ＋０．１ｍｇ／ＬＮＡＡ的Ｂ５培养基上,形成体细胞胚并发育成完整植株。     

巴氏醋杆菌纤维素发酵培养基成分研究

通过试验探索出氏醋杆菌合成醋酸菌纤维素的适宜培养基成分为蛋白胨１．０％,酵母膏０．５％,蔗糖２％,乙醇１％,Ｎａ２ＨＰＯ４　０．２％,ｐＨ６．０;３０℃时静置培养６ｄ,醋酸菌纤维素产量可达９．８５ｇ／Ｌ。     

乌龟胚胎及仔龟的卵黄代谢

乌龟卵、卵黄、剩余卵黄和仔龟的含水量分别为６８．８７％、６１．４７％、６０．７５％和７６．４３％;干重分别为２．２９１５±０．２１０１ｇ,１．３０７１±０．２９１３ｇ,０．２６８１±０．０２４１ｇ和１．２３０５±０．２９９４ｇ;脂肪含量分别为１８．０３％、３１．７６％、３２．１０％和１９．３０％。卵黄、剩余卵黄和仔龟的热值分别为６．７１ｋｃａｌ／ｇＤＭ,６．７６ｋｃａｌ／ｇＤＭ和４．１０ｋｃａｌ／     

重组大肠杆菌生产谷胱甘肽发酵条件的研究

研究了重组Ｅ．Ｃｏｌｉ产ＧＳＨ的发酵条件,重点考察了添加酵母膏、前体氨基酸和ＡＴＰ的影响。结果发现,前体氨基酸和ＡＴＰ均能促进胞内ＧＳＨ的积累,若在发酵０ｈ和１２ｈ分别加入２０ｇ／ＬＡＴＰ和９ｍｍｏｌ／Ｌ前体氨基酸,则细胞干重和胞内ＧＳＨ含量可分别比对照提高２４％和１４倍。应用正交试验得出的针对细胞干重和ＧＳＨ总量的最佳组合,最大细胞干重和ＧＳＨ总量比原试验中的最好结果分别提高了１０％和２６％。在分析了该菌对葡萄糖利用情况的基础上,对该菌进行了指数流加培养,２５ｈ细胞干重与发酵液内ＧＳＨ总量分别达到８０ｇ／Ｌ和８８０ｍｇ／Ｌ,比摇瓶最好结果分别提高了８３和４６倍。     

重组人粒细胞集落刺激因子的纯化

重组人粒细胞集落刺激因子（ｒｈＧ－ＣＳＦ）在工程菌ｐＣＧ－１／ｒｈＧ－ＣＳＦ／ＤＨ５ａ中以无活性的包涵体形式大量表达。经过菌体破碎分离包涵体、包涵体变性复性后,ｒｈＧ－ＣＳＦ的活性得到恢复。用离子交换和疏水层析纯化了ｒｈＧ－ＣＳＦ,比活性达１．５７×１０８ｕ／ｍｇ,纯度大于９８％。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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     

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.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.