中国红豆杉悬浮培养细胞的超低温保存

对中国红豆杉悬浮细胞超低温保存中几个主要因素进行多方面对比研究。结果表明,取培养16d的细胞进行超低温保存效果最好,10％DMSO＋8％葡萄糖作为冰冻保护剂对冷冻细胞起到最佳的保护效果;较好的降温程序是在0℃中预处理30min后移入－20℃中停留180min,然后转入－70℃中停留30min,最后投入－196℃液氮中保存。该实验还对保存后细胞的恢复性生长进行了验证。     

Characterisation of carboxymethyl cellulose and polyacrylamide graft copolymer

The synthesis of carboxymethyl cellulose-g-polyacrylamide was carried out by a ceric ion induced solution polymerization technique. By varying the amount of catalyst and monomer, six different grades of graft copolymers were synthesized. These graft copolymers were characterized by elemental analysis, infrared spectroscopy, rheological studies, scanning electron microscopy, thermal analysis, viscosity measurement and X-ray diffractometry. They exhibit distinguished flocculation characteristics in various suspensions and effluents. Their flocculation and viscosifying characteristics are drastically enhanced on their hydrolysis.     

Simultaneous production of anthocyanin and triterpenoids in suspension cultures of Perilla frutescens

When cultivated in Murashige & Skoog medium supplemented with 0.2 mg l⁻¹ 2,4-dichlorophenoxy acetic acid and 0.5 mg l⁻¹ 6-benzyladenine, Perilla frutescens cells in suspension culture grew rapidly reaching about 13.6 g dry wt l⁻¹ after 12 days. The cell line produced both anthocyanin 0.9 g l⁻¹ and triterpenoids: 16 mg l⁻¹ oleanolic acid (OA), 25 mg l⁻¹ ursolic acid (UA) and 14 mg l⁻¹ tormentic acid (TA). When P. frutescens cells of 7-day-old cultures were exposed to a yeast elicitor at 0.5–5% (v/v) for 7 days, it was found that anthocyanin content peaked at 10.2% of dry weight with yeast elicitor at 1% (v/v) whereas the maximum production of oleanolic acid and ursolic acid in cultures treated with 2% (v/v) yeast elicitor was 19 and 27 mg l⁻¹, a 46 and 24% increase over the control, respectively. This is the first report of simultaneous production of both anthocyanin and triterpenoids in a single culture system.     

长春花悬浮细胞培养体系对脱氢表雄酮的生物转化

利用长春花(Catharanthus roseus(L.)G.Don)悬浮细胞培养体系对脱氢表雄酮进行了生物转化,通过柱层析及制备薄层层析进行分离纯化,并利用核磁共振氢谱、碳谱以及ESI等仪器分析手段进行了化合物的结构鉴定,分离到1 3个转化产物,并对其中的9个进行了结构鉴定,它们分别是:androst-4-ene-3,17-dione(Ⅰ)、6α-hydroxyandrost-4-ene-3,17-dione(Ⅱ)、6α,17β-dihydroxyandrost-4-en-3-one(Ⅲ)、6β-hydroxyandrost-4-ene-3,17-dione(Ⅳ)、17β-hydroxyandrost-4-en-3-one(Ⅴ)、15α,17β-dihydroxyandrost-4-en-3-one(Ⅵ),15β,17β-dihydroxyandrost-4-en-3-one(Ⅶ)、14α-hydroxyandrost-4-ene-3,17-dione(Ⅷ)和17β-hydroxyandrost-4-ene-3,16-dione(Ⅸ).所鉴定的9个化合物均为首次通过生物转化的方法从长春花悬浮细胞培养体系中分离得到.     

密粘褶菌Gloeophyllum trabeum胞外低分子量多肽的分离纯化及其对纤维素生物降解作用

通过HPLC高效液相层析由褐腐真菌中能强烈降解木质纤维素的代表菌株密粘褶菌Gloeo phyllumtrabeum的胞外培养液 ,分离纯化得到一低分子量的活性多肽组分 (Gt因子 ) .Gt因子具有较好热稳定性 ,在pH 2 5～ 6 5范围内保持稳定 .Gt因子分子量在 4 0 0 0左右 ,等电点pI 6 6 .Gt因子具有络合Fe3 + 的能力 ,且能够将Fe3 + 还原为Fe2 + .在O2 存在时 ,能以纤维素物质为电子供体形成羟基自由基HO·.利用循环伏安法 ,观察到Gt因子与纤维素底物之间的氧化还原过程 .研究表明 ,Gt因子极有可能在褐腐菌的纤维素降解初期起着重要的作用 .     

Marine eutrophication and benthos: the need for new approaches and concepts

In this review, using examples drawn from field observations or experimental studies, our goals are (i) to briefly summarize the major changes, in terms of species composition and functional structure, occurring in phyto and zoobenthic communities in relation to nutrient enrichment of the ecosystems; particular interest is given to the major abiotic and biotic factors occurring during the eutrophication process, (ii) to discuss the direct and indirect influences of benthic organisms on eutrophication and whether the latter can be controlled or favoured by benthos; most benthic species play a major role in the process of benthic nutrient regeneration, affecting primary production by supplying nutrients directly and enhancing rates of pelagic recycling; experimental studies have shown that the impact of benthic fauna on benthic–pelagic coupling and nutrient release is considerable. Thus, once the eutrophication process is engaged—that is, high organic matter sedimentation—it may be indirectly favoured by benthic organisms; benthos should always be considered in eutrophication studies, (iii) to evaluate the limits of our observations and data, highlighting the strong need for integrated studies leading to new concepts. Coastal ecosystems and benthic communities are potentially impacted by numerous human activities (demersal fishing, toxic contaminants, aquaculture…); in order to design strategies of ecosystem restoration or rehabilitation, we have to better understand coastal eutrophication and develop tools for quantifying the impacts; in order to achieve this goal, some possible directions proposed are: integrated studies leading to new concepts, model development based on these concepts and finally comparison of various ecosystems on a global scale.     

红豆杉细胞悬浮培养生产紫杉醇研究进展

介绍了近年来由红豆杉细胞培养生产紫杉醇领域取得的进展,其中特别介绍了由紫杉醇生物合成途径及其代谢酶类的研究发展而来的用基因工程方法改良细胞系,为提高紫杉醇产量而采取添加前体物质,诱导子,抑制子等方面的研究。     

水杨酸、茉莉酸甲酯和乙烯利对野葛细胞悬浮培养生产葛根素的影响

野葛〔Ｐｕｅｒａｒｉａｌｏｂａｔａ(Ｗｉｌｌｄ.)Ｏｈｗｉ〕是我国及其他东亚国家传统的药用资源,其主要药用成分为葛根素,广泛用于治疗多种心血管疾病[1]。由于近年来生态环境的人为破坏,野生野葛资源已不能满足人们对葛根素药物的需求,通过细胞工程可以实现野葛资源的可持续性开发。本项目组已经建立了野葛组织培养和植株再生[2]及细胞悬浮培养体系[3],研究结果表明,悬浮细胞培养物能够生产葛根素,但产量仍有待于提高[3]。已知水杨酸(ｓａｌｉｃｙｌｉｃａｃｉｄ,ＳＡ)、乙烯和茉莉酸类化合物(ｊａｓｍｏｎａｔｅｓ,ＪＡｓ)能够在高…     

Synthesis and properties of anionic cellulose ethers: influence of functional groups and molecular weight on flowability of concrete

The suitability of anionic cellulose ethers as superplasticizers and the effect of chemical structure on the fluidity of cement mixtures was investigated. To elucidate the influence of molecular weight and degree of cellulose backbone substitution, cellulose and hydroxyethyl cellulose with molecular weights <50,000 g/mol were synthesized by acid-catalyzed and oxidative degradation. Commercial as well as degraded samples were functionalized by carboxymethylation and sulfobutylation, controlling the degree of substitution (DS) by the molar ratio of reactants and by taking advantage of the high reactivity of sultones towards salts of carboxylic acids, even in aqueous solutions. The fluidizing effect of the cellulose ethers with anionic ‘cement-anchoring‘ groups was prescreened, measuring the static flow of cement pastes. The results indicated a high potential of sulfobutylated cellulose mixed ethers as dispersing agents for concrete. The fluidizing action increased with increasing DS and an optimum range of molecular weight between 100,000 and 150,000 g/mol was found.