动物细胞培养过程中的细胞凋亡

细胞培养过程中的细胞凋亡是细胞受环境因素的影响而发生的现象。随着对细胞凋亡的分子生物学和细胞生物学了解的深入,显示了有效地控制动物细胞培养中细胞凋亡的巨大潜力。包括采用ＤＮＡ重组技术把抗细胞凋亡的基因导入细胞和在培基中加入具有抗细胞凋亡的生存因子或化合物等手段已用于控制细胞培养过程中的细胞凋亡。这些技术将大大延长细胞达到饱和密度后的培养时间,提高细胞培养系统的生产效率。     

细胞培养中的程序性细胞死亡

许多在商业上广泛应用的细胞株,包括杂交瘤和骨髓瘤细胞,在细胞培养中都会发生程序性死亡,这使培养效率降低。本文简要介绍程序性细胞死亡的特征、与这一过程有关的基因、细胞培养中如何抑制程序性死亡以及常用的检测方法。     

杂交瘤细胞培养的优化

根据杂交瘤细胞培养中单克隆抗体生产的动力学原理,采用灌注培养方式、添加醋酸钾和丰富营养物培养的途径,对反应器放大培养过程进行了优化。每天灌注l／2反应器工作体积,与分批培养相比,细胞密度由4 5×10⁵／ml提高到l1×10⁵／ml,单抗浓度由19mg／L提高到28mg/L;添加1g／L醋酸钾,细胞密度基本保持不变．但单抗浓度增加到38μg／ml;用丰富营养物培养后,细胞密度和单抗浓度分别进一步提高到42×10⁵／ml和94mg/L。抗B型红细胞单抗的血凝滴度,由分批培养的1：32．最终提高到l：256     

Photosynthesis in Cell Suspension Culture of a C4 Plant, Gisekia pharnaceoides L.

Photomixotrophic cell suspension culture was established fromthe leaf derived callus cells of Gisekia pharnaceoides L., aC₄ dicotyledonous weed. The late log phase cells possessed shade-typecharacters such as low chlorophyll a/b ratio, less pronouncedO₂ evolution and CO₂ fixation, saturation of photosyntheticCO₂ fixation at low intensity. The chloroplasts from these cellscontained granal stacking with high degree of a very few granawhich are characterized by their wide and high degree of stackings. The predominant labelling of 3-phosphoglyceric acid and sugarphosphates (40% of the total ¹⁴C incorporated) during 5 s exposureto ¹⁴CO₂ in light and subsequent decrease in percentage of ¹⁴Cin these compounds with increase in exposure time indicatedthe operation of the C₃ pathway in these cells. The simultaneoussynthesis of malate (23% of the total ¹⁴C incorporated) is relatedto the much pronounced glycolytic and tricarboxylic acid cycleactivities in these cells. The initial proliferation of callimainly from the zones of vascular supplies in the leaf, highstarch content of the cells, presence of large starch grainsin all the chloroplasts, activities of Calvin cycle enzymes,heavy labelling of C₃ type intermediates and less labellingof aspartate as early photosynthates and rapid accumulationof radioactivity into starch during ¹⁴CO₂ assimilation indicatedthat most of the cells in photomixotrophic culture were derivedfrom bundle sheath cells or the leaf cells of Gisekia changetheir function under culture conditions. ¹Present address: Tropical Botanic Garden and Research Institute,Navaranga Road, Trivandrum 695 011, India. (Received January 29, 1982; Accepted June 4, 1983)     

Inositol Metabolism in Plants. III. Conversion of Myo-inositol-2-H to Cell Wall Polysaccharides in Sycamore (Acer pseudoplatanus L.) Cell Culture

Prolonged growth of cell cultures of sycamore (Acer pseudoplatanus L.) on agar medium containing myo-inositol-2-(3)H resulted in incorporation of label predominately into uronosyl and pentosyl units of cell wall polysaccharides. Procedures normally used to distinguish between pectic substance and hemicellulose yielded carbohydrate-rich fractions with solubility characteristics ranging from pectic substance to hemicellulose yet the uronic acid and pentose composition of these fractions was decidedly pectic. Galacturonic acid was the only uronic acid present in each fraction. Subfractionation of alkali-soluble (hemicellulosic) polysaccharide by neutralization followed by ethanol precipitation gave 3 fractions, a water-insoluble, an ethanol-insoluble, and an ethanol-soluble fraction, each progressively poorer in galacturonic acid units and progressively richer in arabinose units; all relatively poor in xylose units.Apparently, processes involved in biosynthesis of primary cell wall continued to produce pectic substance during cell enlargement while processes leading to biosynthesis of typically secondary cell wall polysaccharide such as 4-0-methyl glucuronoxylan were not activated.     

繁茂膜海绵原细胞富集细胞团培养过程中的细胞迁移规律

海绵是重要的生物活性物质来源, 近10年来, 从海绵中发现的具有生物活性的新化合物占海洋生物来源的30%以上, 并且大多具有显著的抗肿瘤, 抗艾滋病病毒的活性。但是, 由于海绵生物量不能满足这些活性物质进一步研究和商业化的需求, 目前仅有一种活性物质被成功的商业化, 这不仅是商业开发的损失, 也是提高人类生活质量活动的一种损失。为了解决海绵供给不足的问题, 人们进行了包括化学合成、海绵养殖以及海绵细胞培养在内的多种尝试,目前的研究结果表明, 海绵细胞离体培养技术是最有可能彻底解决海绵供给不足的途径之一。但是由于海绵自身的特殊性, 还没有人成功的建立起海绵细胞系以满足生产需要。人们发现, 海绵细胞的相互接触对于离体海绵细胞长期培养至关重要。经过多年的探索, 大连化物所海洋生物产品工程组建立了开发出了海绵原细胞富集细胞团培养技术, 通过对海绵组织内的原细胞进行富集来获得可长期培养的海绵细胞。海绵原细胞是海绵组织内的“干细胞”, 具有很强的分化、增殖潜力, 同时也是海绵组织内负责消化的主要细胞类型。为了探索海绵原细胞的增殖、分化规律, 本研究基于海绵原细胞富集细胞团培养体系, 构建了海绵细胞培养实时观测平台, 对繁茂膜海绵原细胞、领细胞、上皮细胞3类主要海绵细胞类型在海绵细胞团形成及生长的全过程进行观察, 了解不同类型细胞迁移规律的变化。通过对视频记录进行分析,发现离散的海绵细胞与细胞团内的海绵细胞具有截然相反的运动规律, 海绵细胞的运动具有很强的协同性。伴随原细胞在细胞团内不停息的迁移, 还观察到海绵细胞团内新生骨针的迁移以及细胞间进行颗粒物质的传递。这些信息的获得, 将有助于进一步了解不同细胞的功能与作用, 也有助于在此基础上探索海绵细胞的增殖、分化控制规律。     

动物细胞流加培养的技术现状和发展趋势

流加培养是当前重组蛋白生产的主流培养模式。流加式操作主要是根据细胞对营养物质的不断消耗和需求,设计连续或半连续的流加浓缩营养物,使细胞持续高密度的生长,提高单位反应器体积内目的蛋白产量,从而达到高效生产的目的。流加培养工艺的关键技术主要包培养基的优化设计、流加策略的选择及优化、细胞代谢的调控。     

薰衣草细胞悬浮培养体系的优化

采用正交设计方法对影响薰衣草悬浮细胞生长的因素进行了优化研究,筛选了最有利于薰衣草悬浮细胞生长的培养条件:含有0.025mg/L2,4-D、0.5mg/L6-BA、40g/L蔗糖的B5培养基和120r/min的转速,在此条件下培养15天,悬浮活细胞密度可达到4.4×105个/ml;经过3个月的培养,悬浮细胞的分化率可达到90%以上。通过分析薰衣草细胞对残糖的消耗规律,探讨了蔗糖浓度影响活细胞密度的原因。     

野葛离体培养生产异黄酮类化合物研究进展

野葛含有大量的异黄酮类化合物,其中葛根素是葛属植物特有药用成分。该文综述了野葛细胞和器官培养生产异黄酮类化合物的研究现状以及各种影响葛根素等异黄酮类化合物产生的因素,并评述葛根素的应用前景。     

Inositol Metabolism in Plants. III. Conversion of Myo-inositol-2-3H to Cell Wall Polysaccharides in Sycamore (Acer pseudoplatanus L.) Cell Culture

Prolonged growth of cell cultures of sycamore (Acer pseudoplatanus L.) on agar medium containing myo-inositol-2-³H resulted in incorporation of label predominately into uronosyl and pentosyl units of cell wall polysaccharides. Procedures normally used to distinguish between pectic substance and hemicellulose yielded carbohydrate-rich fractions with solubility characteristics ranging from pectic substance to hemicellulose yet the uronic acid and pentose composition of these fractions was decidedly pectic. Galacturonic acid was the only uronic acid present in each fraction. Subfractionation of alkali-soluble (hemicellulosic) polysaccharide by neutralization followed by ethanol precipitation gave 3 fractions, a water-insoluble, an ethanol-insoluble, and an ethanol-soluble fraction, each progressively poorer in galacturonic acid units and progressively richer in arabinose units; all relatively poor in xylose units.