稀土元素对水母雪莲细胞生长及黄酮类化合物合成的影响

研究了稀土元素钕(Nd3+)、铈(Ce3+)、镧(La3+)和混合稀土(MRE)对摇瓶液体培养的水母雪莲细胞生长及黄酮类化合物合成的影响. 发现Ce3+和La3+及混合稀土可促进雪莲细胞的生长及黄酮类化合物的合成,其中以Ce3+效果最佳. 当初始浓度为0.025 mmol/L的Ce3+添加到改良的MS培养基中时,细胞生物量和黄酮类化合物产量最高,分别可达17.7 g/L及942 mg/L,分别是不添加稀土元素的对照实验的134.4%和166.7%;同时发现在培养基中不含外源激素6-BA的条件下,合适浓度的Ce3+可替代6-BA对雪莲细胞生长及黄酮类化合物合成的促进作用,而在培养基中不含NAA时,Ce3+不能替代NAA对雪莲细胞生长及黄酮类化合物合成的促进作用.     

Studies on culture condition of new marine bacterium Zooshikella sp. SY01

New marine bacterium Zooshikella sp. SY01, producer of prodigiosin, was isolated from the seawaters of Sanya Bay. The culture conditions of this bacterium were investigated. Zooshikella sp. SY01 was cultured in 2216E media which contained tryptophan, histidine, lactonic acid, camphor, limonene, casein, diphenyl guanidine, coumarin and 1,3-dinitrobenzene, respectively. After 5 days cultivation, the extracts of different culture broths were detected by direct infusion mass spectroscopy using positive ESI mode. As the results, tryptophan, histidine and casein didn’t show any observable influences on the biosynthesis of prodigiosin. Lactonic acid, camphor, limonene, diphenyl guanidine, coumarin could inhibit the bacterium growth and prodigiosin biosynthesis to a certain extent, slower the culture broth to turn red. However, 1,3-dinitrobenzene inhibited the bacteria to produce prodigiosin completely. MS data suggested that various metabolites with chemodiversity were produced in different culture media. In particular, a series of high-molecular-weight compounds with high relative abundances were observed in the medium containing limonene. To further optimize the culture condition, more new prodigiosin analogues and lead compounds can be obtained and the goal of “one strain-many compounds” can be achieved. __________ Translated from Acta Scientiarum Naturalium Universitatis Sunyatseni, 2007, 46(6): 55–58 [译自: 中山大学学报(自然科学版)]     

GPC STUDIES ON BACTERIAL CELLULOSE

The aim of the present study was to examine the effect of time duration of bacterial cellulose (BC) biosynthesis as well as the culture medium composition on molecular parameters of the obtained polymer. It was found that the degree of polymerization of BC increases as the duration of biosynthesis is prolonged up to 6 days. A further prolongation of the process to 28 days lowers the degree of polymerization (DP) value and increases polydispersity. An examination of the effect of culture medium composition on the biosynthesis pointed out that the course of the process is mainly influenced by the chemical nature of the carbon source. The best results for molecular parameters were obtained for a medium containing 4% of glucose.     

Lethal effect ofcis- but nottrans-22-dehydrocholesterol on mouse fibroblast cells

cis- andtrans-22-dehydrocholesterol were incorporated into the culture medium for mouse fibroblast cells. Although neither isomer had an effect on sterol biosynthesis, thecis isomer inhibited cell growth and viability and increased Rb⁺ efflux from the cells. Thetrans isomer had no effect on growth and could replace exogenous cholesterol for growth of cells for which sterol biosynthesis was blocked by 25-hydroxycholesterol.     

Pineapple agroindustrial residues for the production of high value bacterial cellulose with different morphologies

Bacterial cellulose (BC) with different morphologies was biosynthesized by Gluconacetobacter medellinensis strain under static and dynamic culture conditions using sugar cane juice and pineapple residues as sources of carbon and other nutrients. Hestrin and Schramm's standard culture medium was used as reference. The fermentation condition and resulting yield, physico‐chemical properties, and morphology relationships of obtained cellulose were analyzed. Pineapple agroindustrial residues can be envisaged as an inexpensive and sustainable alternative resource for the production of different BC morphologies. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41237.     

低相对分子质量细菌纤维素的生物合成

通过木醋杆菌菌株HN001静态培养,生物合成了低相对分子质量细菌纤维素(LMBC),其培养基是以海南椰子水为原料,添加了糖和其他盐类化合物。研究了影响LMBC产率的几个因素,如培养温度、培养时间和培养基初始pH。获得高产率LMBC的适宜条件是:培养时间72 h,培养温度33℃,培养基初始pH=4,LMBC产率达1.2 g/L。用凝胶过滤色谱仪(GFC)测定了其相对分子质量及其分布。研究了培养基初始pH从3.5到5.5变化对LMBC相对分子质量及其分布的影响,结果表明,该pH范围内相对分子质量的变化不大,其分布指数均约为1.3,说明相对分子质量均匀。用透射电镜测试了其形貌,证明LMBC的形貌近似球形,大小约20 nm;LMBC冷冻干燥后经红外光谱确证了其结构。     

Biosynthesis and characterization of bacteria cellulose–alginate film

A novel polysaccharide membrane containing alginate in bacterial cellulose matrix was synthesized by Acetobacter xylinum under static conditions using a culture medium supplementation with sodium alginate. By increasing alginate content, the bacterial cellulose–alginate (BCA) membrane was more hydrophilic and the film structure became denser with the smaller average pore size. Scanning electron microscope images displayed the deposits of alginate gel on the surfaces of the multilayer cellulose film. The declines in the tensile strength, the Young's modulus, and the elongation at break of the BCA membrane were dependent on the degree of alginate supplement. The BCA membrane showed higher water absorption capacity. The addition of alginate slightly affected the water vapor transmission rate but remarkably decreased the oxygen transmission rate of the membrane. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

多糖改性细菌纤维素的制备

合成细菌纤维素时向培养基中添加了海藻酸钠、羧甲基纤维素、羧甲基壳聚糖等多糖,制备出了性能更优异的改性细菌纤维素。采用红外光谱和扫描电镜对所得产物进行表征,并测试了合成纤维素的产量、湿膜含水量以及对金属离子的吸附性能。     

Comparison of different cultivation modes and light intensities using mono‐cultures and co‐cultures of Haematococcus pluvialis and Chlorella zofingiensis

BACKGROUND: Recent studies indicate that microalgal cultivation using organic carbon sources has the potential to provide high yields. Haematococcus pluvialis and Chlorella zofingiensis, two important carotenoid producers, were selected for co‐culture cultivations to utilize the unique advantages of both organisms. A co‐culture production process was investigated in terms of the effects of organic carbon source, co‐cultivation method, and light intensity on carotenoid production. RESULTS: The addition of 5 g L^?1 glucose resulted in a growth rate of 0.60 day^?1 for H. pluvialis and 0.59 day^?1 for C. zofingiensis, which were higher than those for other carbon sources tested and the control group. Incremental increase of light intensity instead of direct increase to 170 µE m^?2s^? prevented cell loss in both cultures. Co‐cultivation based on cell numbers (60% H. pluvialis and 40% C. zofingiensis) prevented population domination of one microalgae over the other. The biomass production rate of the co‐culture was higher (0.61 g L^?1 day^?1) in glucose‐enriched medium. The total carotenoid content of the co‐culture in the control culture was higher (0.83 mg total carotenoids g^?1 cell) than that obtained in glucose‐enriched medium (0.54 mg total carotenoids g^?1 cell) but not as high as the amounts reached in mono‐cultures. CONCLUSION: Total carotenoid content of the mono‐cultures gave higher yields in standard bold basal medium (BBM). Preliminary high performance liquid chromatography (HPLC) studies indicated a variation in the amounts of astaxanthin isomers produced. Further studies are in progress to determine the effects of carbon‐enriched media and co‐cultivation on the type of isomers and caretenoids produced. Copyright © 2010 Society of Chemical Industry     

Effects of different culture media and oxygen upon lipids ofEscherichia coli K-12

The effects of altering the chemical composition of the culture media and the oxygen content of the environment upon the lipid metabolism ofEscherichia coli K-12 were investigated. WhenE. coli cells were grown on the same culture medium but under aerobic and anaerobic conditions, an increase in the free fatty acids of anaerobically grown cells was observed with a disproportionate increase in the unsaturated fatty acids. When glucose was the sole carbon source, both fatty alcohols and hydrocarbons were detected as component lipids of these cells, whether growth occurred under aerobic or anaerobic conditions. Based upon this observation, acetate is considered the initial precursor for fatty alcohol and hydrocarbon biosynthesis. A possible metabolic pathway involving fatty alcohols in hydrocarbon synthesis has been postulated.     

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.     

超声波对新疆紫草悬浮培养细胞生长和紫草素合成的影响

探讨了超声波功率、超声波处理时间对新疆紫草细胞生长和紫草素合成的影响. 研究结果表明,超声波对悬浮培养的新疆紫草细胞生长有促进作用,低功率长时间或高功率短时间的超声处理对细胞生长比较有利. 在优化条件下(200 W超声处理1 min),培养结束时的生物量比对照提高61%. 超声波也可以提高新疆紫草悬浮培养细胞的紫草素含量和产量,接种后即进行超声波处理,超声波功率密度为39.9 mW/cm3、超声时间为3 min时,细胞紫草素含量和产量最高,达到2.72%和294 mg/L,分别比对照组提高了64%和135%. 超声波是通过提高细胞苯丙氨酸解氨酶的活力来强化紫草素的生物合成途径.     

Electrospun poly (N-isopropylacrylamide-co-acrylic acid)/cellulose laurate blend nanofibers containing adapalene: Morphology,drug release,and cell culture studies

In this work, a thermo- and pH-sensitive polymer based on poly (N-isopropylacrylamide-co-acrylic acid)/cellulose laurate blend [P(NIPAAm-co-AAc)/CL] was electrospun to produce nanofibers containing adapalene. The synthesized P(NIPAAm-co-AAc), and CL were characterized by ATR-FTIR and ¹H NMR spectroscopies. The thermal behavior of the electrospun nanofibrous samples were determined by a DSC. Afterward, the drug release in different temperatures and pHs from the nanofibers was investigated by UV-vis spectrophotometry and then the LCST behavior of the samples containing adapalene was observed by an ESEM. Moreover, the fibroblast cells culture was carried out with and without adapalene and the cell cytotoxicity of the samples was evaluated via MTT assay. The results from (H&E) and DAPI staining of the viable cells onto the samples surfaces revealed the adapalene has a remarkable short-term potential for the fibroblast cells mortality. It was found that the adapalene loaded electrospun nanofibrous samples enabled to minimize the adverse side effects of the drug by controlling release during three days of cell culture.     

Studies on the production of lipids in fungi XIII. Changes of amount and composition of lipids in fungi in species of the genusPellicularia from cellulose by cultural conditions

The influence of growth temperature, carbon to nitrogen (C/N) ratio of the medium and the nitrogen source on the cell and lipid formation from cellulose by the speciesfilamentosa andpraticola of the genusPellicularia were investigated. The strains of thePellicularia genus fungi can be grown well utilizing powdery cellulose and sugar cane bagasse as the carbon source. The amount of lipids accumulated in the mycelium varied considerably depending on the difference in the cell growth associated with the cultivation condition, and the difference in the strain, C/N ratio and nitrogen source. The maximum accumulation of lipids in the mycelium (256 mg/400 ml of the medium) from cellulose was observed at 20 C with a C/N ratio of 5.7 using potassium nitrate as the nitrogen source forPellicularia filamentosa var.solani IFO 5879. Protein formation in the liquid medium is at its peak when the cell growth is at its maximum. The fatty acid compositions of the neutral and polar lipid fractions also were determined. Linoleic acid is the major fatty acid component of both fractions. The change in the total lipid content is less than 10% under any cuitivation condition.     

Development of novel biocomposites based on the clean production of microbial cellulose from dairy waste (sour whey)

This work explores the production of kombucha-derived bacterial cellulose (KBC) from sour whey via the fermentation method using Komagatacibacter xylinus. The biosynthesis process was optimized by design of experiments and the results displayed highest KBC yield at 1000 ml/L sour whey waste, 87.39 g/L cane sugar, 6 g/L black tea, and 78.91 ml/L bacteria volume under 21 days culture period at 30°C. Optimum fermentation batch efficiency was achieved in large scale with cultured medium depths of 0.5 cm and low-residual bacteria suspension volume of 72.31 ± 8.74 ml. The obtained KBC membranes were analyzed by SEM, FTIR, XRD, and TGA. The obtained results show no significant differences for all prepared KBC samples when compared to pristine bacterial cellulose from standard Hestrin and Schramm (HS) medium. In addition, the optimized KBC was investigated as a suitable bio-filler in the preparation of biocomposite materials. The prepared biocomposites as leather alternative were further characterized and their mechanical tensile strength and elongation at break determined in the range of 135.61 ± 9.15 to 154.89 ± 9.09 N/mm² and 31.06 ± 0.32 to 92.33 ± 6.91%, respectively. This model obtained depicts high-yield production of KBC and its potential in the preparation of biocomposites.     

Stepwise Proliferation and Chondrogenic Differentiation of Mesenchymal Stem Cells in Collagen Sponges under Different Microenvironments

Biomimetic microenvironments are important for controlling stem cell functions. In this study, different microenvironmental conditions were investigated for the stepwise control of proliferation and chondrogenic differentiation of human bone-marrow-derived mesenchymal stem cells (hMSCs). The hMSCs were first cultured in collagen porous sponges and then embedded with or without collagen hydrogels for continual culture under different culture conditions. The different influences of collagen sponges, collagen hydrogels, and induction factors were investigated. The collagen sponges were beneficial for cell proliferation. The collagen sponges also promoted chondrogenic differentiation during culture in chondrogenic medium, which was superior to the effect of collagen sponges embedded with hydrogels without loading of induction factors. However, collagen sponges embedded with collagen hydrogels and loaded with induction factors had the same level of promotive effect on chondrogenic differentiation as collagen sponges during in vitro culture in chondrogenic medium and showed the highest promotive effect during in vivo subcutaneous implantation. The combination of collagen sponges with collagen hydrogels and induction factors could provide a platform for cell proliferation at an early stage and subsequent chondrogenic differentiation at a late stage. The results provide useful information for the chondrogenic differentiation of stem cells and cartilage tissue engineering.     

Yeast‐mediated stereo‐selective reduction of estrone by continuous cell culture with dual stirred tanks for product yield improvement

BACKGROUND: β‐Estradiol is an important hormone for the treatment of breast cancer and osteoporosis. β‐Estradiol can be produced via Saccharomyces cerevisiae mediated reduction of estrone. However, substrate inhibition and low production yield have been observed in the batch cell culture. RESULTS: An innovative continuous cell culture with dual stirred tanks in series was designed to solve the above problems. The growth medium was fed continuously to the incubation tank where the cells were incubated aerobically; the viable cells were then supplied continuously to the reaction tank in which the yeast‐mediated anaerobic reduction of estrone was performed with continuous feed of the substrate medium and continuous withdawal of the reaction cell culture. Thus, an increase in cell productivity from about 3‐fold to 7‐fold was obtained when compared with the batch cell culture. The β‐estradiol yield was improved to 64.8% on the second reaction day, accompanied by an accumulation of 12.9 mg β‐estradiol on the third reaction day. The yield was about 10% more and the accumulated recovery of β‐estradiol was 4.3‐fold better than with the batch cell culture. The diastereomeric excess value (%de) of β‐estradiol was more than 99%. CONCLUSION: A high product yield with excellent stereo‐selectivity was achieved in a short reaction period with the developed continuous cell culture and the dual stirred tank. Copyright © 2010 Society of Chemical Industry     

Cellulose biosynthesis inhibitors: comparative effect on bean cell cultures

The variety of bioassays developed to evaluate different inhibition responses for cellulose biosynthesis inhibitors makes it difficult to compare the results obtained. This work aims (i) to test a single inhibitory assay for comparing active concentrations of a set of putative cellulose biosynthesis inhibitors and (ii) to characterize their effect on cell wall polysaccharides biosynthesis following a short-term exposure. For the first aim, dose-response curves for inhibition of dry-weight increase following a 30 days exposure of bean callus-cultured cells to these inhibitors were obtained. The compound concentration capable of inhibiting dry weight increase by 50% compared to control (I(50)) ranged from subnanomolar (CGA 325'615) to nanomolar (AE F150944, flupoxam, triazofenamide and oxaziclomefone) and micromolar (dichlobenil, quinclorac and compound 1) concentrations. In order to gain a better understanding of the effect of the putative inhibitors on cell wall polysaccharides biosynthesis, the [(14)C]glucose incorporation into cell wall fractions was determined after a 20 h exposure of cell suspensions to each inhibitor at their I(50) value. All the inhibitors tested decreased glucose incorporation into cellulose with the exception of quinclorac, which increased it. In some herbicide treatments, reduction in the incorporation into cellulose was accompanied by an increase in the incorporation into other fractions. In order to appreciate the effect of the inhibitors on cell wall partitioning, a cluster and Principal Component Analysis (PCA) based on the relative contribution of [(14)C]glucose incorporation into the different cell wall fractions were performed, and three groups of compounds were identified. The first group included quinclorac, which increased glucose incorporation into cellulose; the second group consisted of compound 1, CGA 325'615, oxaziclomefone and AE F150944, which decreased the relative glucose incorporation into cellulose but increased it into tightly-bound cellulose fractions; and the third group, comprising flupoxam, triazofenamide and dichlobenil, decreased the relative glucose incorporation into cellulose and increased it into a pectin rich fraction.     

Structure of cellulose II

A reduced unit cell derived from the presently accepted unit cell and a new parallel chain arrangement is proposed for cellulose II (regenerated cellulose). In the present structure, all the cellulose chains are identical and there is only one chain passing through each unit cell. The intensity data for all reflections with d spacings greater than 1.747 Å have been calculated and were found to be in good agreement with the corresponding observed x-ray intensities. The calculated agreement factor is R = 0.50. Two intrachain hydrogen bonds parallel to the fiber axis and one interchain hydrogen bond perpendicular to the fiber axis stabilize the structure. The hydrogen bonding network is in fair agreement with infrared dichroic data, and the chain arrangement conforms to stereo-chemical criteria. No short contacts are observed. The parallel chain is also compatible with the structure of cellotetraose and the accepted hypothesis of cellulose biosynthesis, as well as the latest parallel structure for Valonia.     

Traumatic Acid Reduces Oxidative Stress and Enhances Collagen Biosynthesis in Cultured Human Skin Fibroblasts

Traumatic acid (TA) is a plant hormone (cytokinin) that in terms of chemical structure belongs to the group of fatty acids derivatives. It was isolated from Phaseolus vulgaris. TA activity and its influence on human cells and organism has not previously been the subject of research. The aim of this study was to examine the effects of TA on collagen content and basic oxidative stress parameters, such as antioxidative enzyme activity, reduced glutathione, thiol group content, and lipid peroxidation in physiological conditions. The results show a stimulatory effect of TA on tested parameters. TA caused a decrease in membrane phospholipid peroxidation and exhibited protective properties against ROS production. It also increases protein and collagen biosynthesis and its secretion into the culture medium. The present findings reveal that TA exhibits multiple and complex activity in fibroblast cells in vitro. TA, with its activity similar to unsaturated fatty acids, shows antioxidant and stimulatory effects on collagen biosynthesis. It is a potentially powerful agent with applications in the treatment of many skin diseases connected with oxidative stress and collagen biosynthesis disorders.