植物细胞培养生物反应器的研究进展

介绍了用于植物细胞培养的搅拌式反应器、非搅拌式反应器、光反应器及固定化反应器等,为植物细胞培养中反应器的选择和设计提供参考     

Recent molecular advances on downstream plant responses to abiotic stress

Abiotic stresses such as extremes of temperature and pH, high salinity and drought, comprise some of the major factors causing extensive losses to crop production worldwide. Understanding how plants respond and adapt at cellular and molecular levels to continuous environmental changes is a pre-requisite for the generation of resistant or tolerant plants to abiotic stresses. In this review we aimed to present the recent advances on mechanisms of downstream plant responses to abiotic stresses and the use of stress-related genes in the development of genetically engineered crops.     

High density culture of Coptis japonica cells increases berberine production

A high density culture method was devised to improve the yield of berberine from highly productive cells of Coptis japonica. By adjusting aeration and stirring, Coptis cells were cultured at densities of up to 75 g dm^?3 (dry weight) in a culture tank fitted with a hollow-paddle type stirrer. Whereas a maximum density of 30 g dm^?3 of C. japonica cells could be used in ordinary batch culture, 48 g dm^?3 could be used in a fed-batch culture in which the amounts of the nutrients in the medium were made proportional to the density of the inoculum. Moreover, in fed-batch culture done with modified medium, the composition of which had been determined from the amounts of components incorporated in cells grown at the usual density for ordinary batch culture, the cell yield was improved to 55 g dm^?3 and the berberine yield to 3.5 g dm^?3.     

A采油厂安全文化建设研究

阐述了安全文化建设对采油厂的重要作用,分析A采油厂安全文化建设的现状和存在的问题,介绍安全文化体系的构成和建设步骤,提出安全文化建设的措施,促进体系的完善和各项制度的顺利落实,帮助企业实现安全生产目标     

Development of a photoresponsive cell culture surface: Regional enhancement of living‐cell adhesion induced by local light irradiation

Using a functional polymer containing nitrospirobenzopyran residues and poly(ethylene glycol), we developed a photoresponsive cell culture surface (PRCS), at which the cell adhesion can be enhanced locally by UV light irradiation (350–400 nm, 35 mW/cm², 5 min) even on the region where living cells exist. Cell adhesion was evaluated by observing BALB/3T3 fibroblasts, which had been seeded on PRCS and then irradiated with UV light regionally, after 12 h incubation and subsequent washing to remove scarcely adhering cells. As a result, it was confirmed that the number of remaining cells in irradiated region was at most 2.5 times greater than that in nonirradiated regions, suggesting the implementation of a novel scheme to manipulate living cells individually by light irradiation in a parallel and simultaneous manner. Influence of the composition of the polymer material consisting the substrate surface was also investigated systematically. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 495–499, 2006     

Metabolic responses of microorganisms growing on inhibitory substrates in nonsteady state culture

The dynamics of metabolic activity of Pseudomonas putida cultured on phenol in a nonsteady state, resulting from simultaneous step increases (or decreases) in dilution rate and feed phenol concentration, were studied. Metabolic activity was determined by the uptake rate, defined as the mass of phenol degraded by a unit mass of bacteria in unit time. A minimum duration of nonsteady state was necessary to induce the metabolic pathway. The induction time for Pseudomonas putida cultured on phenol was approximately 30 min, irrespective of the type of disturbance applied. The Monod-Haldane equation was applied to fit the experimental values of uptake rate and the best kinetic parameters were calculated by the nonlinear least squares technique. Values of the kinetic parameters differed both for each parameter and type of disturbance investigated. For simultaneous step increases in dilution rate and feed phenol concentration, the value of u_m in the transient state first increased monotonically approximately four times and then decreased monotonically to the new steady state value after three residence times. Values of K_s and K_i attained those at the new steady state after three residence times, the highest being approximately three times greater than those of the steady state prior to disturbance. For simultaneous step decreases in D and S_O, values of u_m, K_s and K_i reached those at the new steady state values after four residence times.     

Evaluation of the hydraulic and hydrodynamic parameters influencing photo-catalytic degradation of bio-persistent pollutants in a pilot plant

A kinetic study on the photo-catalytic degradation of bio-persistent micro-pollutants, as methyl red and methylene blue dyes, was carried out on an innovative unit by changing the hydraulic and hydrodynamic parameters of the system. The catalyst (TiO₂, anatase) was embedded into a cement matrix and deposited at the bottom of a channel to activate the UVB photo-degradation reactions. The influence of the catalyst dosage, substrate concentration c₀, and pH was evaluated on the degradation rates. The optimum catalytic dose was obtained at 0.79?g/cm³ while the best results were observed at 0.7?mg/L influent dye concentration. The pH of the solution influenced the sorption phenomena because the charge of the substrates functional groups as well as the charge of the catalyst surface were affected by this parameter. Different unit geometries, hydraulic loads (h_w) and gradients (i) affected speed and flow-rate (Q) of the liquid phase and, as a consequence, the irradiated retention times (Irt) of the substrates to the UV/TiO₂ system. Kinetics resulted faster at increasing flow-rates of the liquid flowing through the channel, constant the hydraulic load, whereas the increase in the hydraulic load did not improve the performances. Finally, degradation rates slightly decreased after the increase in the hydraulic gradient of the channel.     

植物DNA甲基化与逆境响应

在逆境胁迫下,植物会根据自身需要调节信号传导途径,从而上调(启动)或下调(关闭)基因表达以确保自身的适应性生长及发育。近年研究显示,植物DNA甲基化变异在响应逆境胁迫过程中发挥着重要作用,生物逆境和非生物逆境都可使植物的甲基化状态发生调控性改变,从而使植物在一定程度上适应和抵抗逆境伤害。本文对植物DNA甲基化及逆境胁迫下甲基化变异方面的研究进展作一综述。     

产朊假丝酵母分批发酵生产谷胱甘肽的代谢通量分析

根据产朊假丝酵母利用葡萄糖作为惟一碳源生物合成谷胱甘肽的代谢网络,利用代谢通量分析方法分析了谷胱甘肽分批发酵不同阶段各代谢途径碳通量的分布和变化规律.在此基础上,通过分阶段温度控制和L-半胱氨酸添加等策略,调节谷胱甘肽分批发酵过程中的代谢通量分布,谷胱甘肽生物合成的产量明显提高,最大增加幅度分别达到23%和91%.同时对这些策略下谷胱甘肽的过量合成机理进行了解释.     

Production of horse radish peroxidase by plant cell culture

Calluses were induced from the stem and the root tissues of horse radish plantlets. Cell aggregate selections were carried out on them to obtain a cell line with higher peroxidase activity, and the isozyme patterns of the peroxidases from the cultured cells and their utility values as a clinical diagnostic reagent were investigated. The repetition of the cell aggregate selection resulted in increases in peroxidase activities in each generation of selection; about eleven fold in the 13th generation of selection from the stem tissues and about nine fold in the 13th generation from the root tissues. One of the cell lines (N5K6-S), originally derived from the stem tissues, after selectin showed a tenfold increase in peroxidase activity within two weeks of culture in a liquid medium. The value as a clinical diagnostic reagent of peroxidases extracted from the N5K6-S cells was estimated to be equivalent to those already commercially available for the same purpose. There were significant differences in the isoenzyme patterns of the peroxidases from root tissues and those from cultured cells. From these results, the possibility of commercial production of peroxidase utilizing plant tissue and cell culture techniques was discussed.     

皮肤细胞培养技术在化妆品功效研究中的应用

皮肤细胞的体外培养技术一直是化妆品相关皮肤领域研究的重要手段。从传统的各种皮肤细胞单层培养以皮肤细胞的三维培养技术等多种培养模型。重建表皮具有分化的特征，与真皮类似物组成简化的人的皮肤。皮肤的三维培养因其具有类似于人体皮肤的特点而成为化妆品研究中的理想模型。这些培养技术的发展对延缓皮肤衰老、美白化妆品配方研制及护发产品开发具有广泛应用价值，更是基础研究必不可少工具。     

Metal-induced oxidative stress and plant mitochondria

A general status of oxidative stress in plants caused by exposure to elevated metal concentrations in the environment coincides with a constraint on mitochondrial electron transport, which enhances ROS accumulation at the mitochondrial level. As mitochondria are suggested to be involved in redox signaling under environmental stress conditions, mitochondrial ROS can initiate a signaling cascade mediating the overall stress response, i.e., damage versus adaptation. This review highlights our current understanding of metal-induced responses in plants, with focus on the production and detoxification of mitochondrial ROS. In addition, the potential involvement of retrograde signaling in these processes will be discussed.     

Experimental determination of maximum effective hydrodynamic stress in multiphase flow using shear sensitive aggregates

Maximum effective hydrodynamic stress, , responsible for the breakup of aggregates with size comparable to Kolmogorov eddies, was experimentally determined in an aerated stirred tank. The proposed method is based on the measurement of the maximum stable aggregates size consisting of poly(methyl methacrylate) nanoparticles. The fractal aggregates were broken under various operating conditions in an aerated stirred tank and calibrated with known flow conditions using contracting nozzles to convert the measured aggregate sizes into hydrodynamic stress. It was found that can vary substantially among studied conditions and its magnitude depends on the controlling mechanism including gas jet during bubble formation, bubble rise, bubble burst at the gas–liquid interface or the turbulence generated by the impeller. The measured values are in good agreement with literature data which supports the applicability of this method to characterize the maximum effective hydrodynamic stress in complicated multiphase flow. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1735–1744, 2015     

Application of residence time distribution technique to the study of the hydrodynamic behaviour of a full‐scale wastewater treatment plant plug‐flow bioreactor

The hydrodynamic behaviour of a full‐scale wastewater treatment plant (WWTP) bioreactor treating municipal wastewater, situated in Granollers (Barcelona, Spain), has been studied by means of a residence time distribution (RTD) technique using lithium (chloride) as tracer. The bioreactor studied is designed to work as a plug‐flow reactor and it is divided into two independent lanes (1 and 2), each one composed of four compartments in series resulting in a total volume of 3970 m³ per lane. During the RTD experiments, working flow was 1000 m³ h^?1 per lane, which implied an ideal mean residence time of 3.97 h. When a lithium chloride tracer was injected in the bioreactor, both lanes showed a similar highly non‐ideal hydrodynamic behaviour, which had an important effect on the reactor's performance. This global RTD was complemented by means of local RTDs in different locations of the bioreactor in order to determine qualitatively the reactor's mixing regime. Different non‐ideal models (namely axial dispersion, tanks‐in‐series and some simple compartment models) have been tested for the modelling of the experimental RTD. The best model fitting RTD data for Lanes 1 and 2 was a configuration consisting of four mixed tanks in series. The RTD study proposed in this work will permit improvement of the reactor's mixing performance, which is of special interest in future projects including simultaneous removal of carbon, nitrogen and phosphorus. Copyright © 2005 Society of Chemical Industry     

Intraparticle cell growth and cell leakage in cultures of Nicotiana tabacum cells immobilized in calcium alginate gel beads

Immobilized Nicotiona tabacum cells in calcium alginate gel beads were prepared under various conditions and then were cultivated. The effects of different conditions of preparation, in relation to concentration of calcium ions (Ca²⁺), on intraparticle cell growth and cell leakage from beads were investigated experimentally. As the amount of Ca²⁺ incorporated into the beads increased, the numbers of cells leaked from the beads into the medium decreased. However, cell growth was inhibited by high Ca²⁺ concentrations in the beads. Optimal conditions existed, which prevented cell leakage without inhibiting intraparticle cell growth. The effect of adding CaCl₂ to the culture medium was also studied. The Ca²⁺, used for the alginate crosslinking, gradually leached from the beads with increasing cultivation time, such that the beads gradually became brittle and fragile. The addition of CaCl₂ was effective in preventing Ca²⁺ loss from the beads and cell leakage. © 2000 Society of Chemical Industry     

克鲁斯假丝酵母分批发酵生产甘油的代谢流分布

采用Candida krusei分批发酵生产甘油，在碳元素平衡基础上作代谢流分析得知，典型生长阶段（6－12h)形成菌体流量较大，占50％以上，且有12％的乙醇流量，甘油流量较小：典型生产阶段（48－54h)甘油流量增大为42%，菌体和乙醇流量为0，有11％的有机酸流量。     

Biocompatible micro-sized cell culture chamber for the detection of nanoparticle-induced IL8 promoter activity on a small cell population

In most conventional in vitro toxicological assays, the response of a complete cell population is averaged, and therefore, single-cell responses are not detectable. Such averaging might result in misinterpretations when only individual cells within a population respond to a certain stimulus. Therefore, there is a need for non-invasive in vitro systems to verify the toxicity of nanoscale materials. In the present study, a micro-sized cell culture chamber with a silicon nitride membrane (0.16 mm²) was produced for cell cultivation and the detection of specific cell responses. The biocompatibility of the microcavity chip (MCC) was verified by studying adipogenic and neuronal differentiation. Thereafter, the suitability of the MCC to study the effects of nanoparticles on a small cell population was determined by using a green fluorescence protein-based reporter cell line. Interleukin-8 promoter (pIL8) induction, a marker of an inflammatory response, was used to monitor immune activation. The validation of the MCC-based method was performed using well-characterized gold and silver nanoparticles. The sensitivity of the new method was verified comparing the quantified pIL8 activation via MCC-based and standard techniques. The results proved the biocompatibility and the sensitivity of the microculture chamber, as well as a high optical quality due to the properties of Si₃N₄. The MCC-based method is suited for threshold- and time-dependent analysis of nanoparticle-induced IL8 promoter activity. This novel system can give dynamic information at the level of adherent single cells of a small cell population and presents a new non-invasive in vitro test method to assess the toxicity of nanomaterials and other compounds.PACS: 85.35.Be, 81.16.Nd, 87.18.Mp     

The Filtration Properties of Atropa belladonna Plant Cell Suspensions; Effects of Hydrodynamic Shear and Elevated Carbon Dioxide Levels on Culture and Filtration Parameters

The filtration properties of Atropa belladonna plant cell suspensions cultured at different bioreactor stirrer speeds and gas-phase carbon dioxide levels were measured. Cell cake compressibility did not vary significantly with culture time, shear intensity or carbon dioxide concentration. Average cell cake permeability decreased by c. 70% with increasing stirrer speeds between 400 and 1000 rpm, and could be correlated with concomitant reductions in cell aggregate size. Permeability was more responsible than other culture parameters, such as growth, cell membrane integrity and protein release, to levels of hydrodynamic energy dissipation in the range 10⁶–10⁹ J m⁻³. Cell cake permeability was significantly affected by carbon dioxide levels of 10 and 15%, but not 2%. Average permeability at 15% CO₂ was reduced by c. 50% compared with the air-sparged control culture, even though aggregate size, morphological characteristics and filtered cake compressibility were unaltered. A distinctive pattern of permeability change over the course of the cultures was observed when the reactor conditions were not inhibitory to growth; however, this pattern was destroyed at medium-to-high shear levels and high carbon dioxide concentrations. © 1997 SCI.     

代谢工程改造解脂耶氏酵母生产脂肪酸及其衍生物

微生物来源的脂肪酸及其衍生物广泛应用于能源、材料和营养化学品等领域,可用于生产航空燃油、聚合物、增塑剂、润滑剂和食品添加剂等。解脂耶氏酵母是一种研究最为透彻的产油脂酵母,具有高产各种脂肪酸及其衍生物的潜力。本文综述了近年来解脂耶氏酵母遗传操作工具的发展,并介绍了通过代谢工程技术改造解脂耶氏酵母生产脂肪酸及其衍生物的进展,在此基础上,展望了通过构建解脂耶氏酵母细胞工厂合成特定脂肪酸及其衍生物的未来发展方向。