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1.
棉纤维分化和发育研究进展   总被引:4,自引:3,他引:1  
棉纤维分化和发育研究进展邱金龙王隆华颜季琼(华东师范大学生物系,上海200062)ADVANCESINTHESTUDYONDIFFERENTIATIONANDDEVELOPMENTOFCOTTONFIBERQiuJin-longWangLong-h...  相似文献   

2.
通过培养的人主动脉平滑肌细胞(hASMC)及脐静脉内皮细胞(hUVEC),应用3H-TdR参入、Northernblot分析、逆转录多聚酶链反应(RT-PCR)、放射免疫分析(RIA)、和紫外比色法等技术观察了人主动脉中硫酸乙酰肝素蛋白聚糖(HSPG)对hASMC和hUVECDNA合成的作用及对血小板源生长因子(PDGF)、PDGF受体、转化生长因子β(TGF-β)、内皮素-1(ET-1)或碱性成纤维细胞生长因子(bFGF)基因表达和肾素-血管紧张系统(RAS)的影响,结果显示,HSPG明显抑制培养的hASMC基础的DNA合成(cpm值为:10385±3263vs,25541±6421,P<0.01)及外源性PDGF诱导的DNA合成(cpm值为:9878±1947vs.13481±44l0,P<0.05);抑制PDGFA链、TGF-Bp和ET-1mRNA表达,提高PDGFa和β受体mRNA的表达;显著降低hASMC培养液中血管紧张素Ⅱ(AngⅡ)的浓度和血管紧张素转换酶(ACE)的活性,推测HSPG抑制PDGFA链、TGF-β及ET-1mRNA表达,降低ACE活性及AngⅡ浓度是其抑制hASMC增殖的重要机  相似文献   

3.
6—BA诱导的带正电荷的葡萄叶过氧化物酶   总被引:7,自引:0,他引:7  
河岸葡萄叶的带正电荷过氧化物酶可受6-BA诱导,但盐,H2O2或Fe^2++H2O2均使叶片COPD活性明显下降,而高浓度的无机盐明显刺激纯COPD活性增加。在以愈创木酚为底物时CPOD最适pH为4.60-5.75,对H2O2的表面Vmax和Km值分别为110U/mg蛋白和1.15mmol/L。  相似文献   

4.
杜氏盐藻细胞质膜具的氧化NAD(P)H,还原Fe(CN)^3-6和O2的氧化还原系统。当Fe(CN)^3-6浓度为0.6mmol/L,氧化NADH的Km为96μmol/L,Vmax为159nmol10^-8cellsmin^-1,最适pH为8.5。TritonX-100可促进NADH和Fe(CN)^3-6的氧化还原活性。NADH能促进藻细胞的氧吸收,最适pH为8.5。在无外源电子供体存在时,细胞质  相似文献   

5.
用酶组织化学和免疫组织化学双标技术,观察了正常SD大鼠基底前脑内侧隔核(MS)、斜角带垂直支(VDB)和水平支(HDB)中NOS阳性神经元的形态和分布及NOS与胆碱能神经元标志物ChAT、NGF受体(NGF-R)和AChE之间的共存关系。结果发现,MS、VDB和HDB的头端NOS阳性神经元较多、胞体较大、突起多,尾端NOS阳性神经元数目较少、胞体较小、突起少而短。NOS+ChAT双标神经元占NOS阳性神经元总数的90%,占ChAT阳性神经元总数的39%;NOS+NGF-R双标神经元占NOS阳性神经元总数的83%,占NGF-R阳性神经元总数的40%;NOS+AChE双标神经元占NOS阳性神经元总数的96%,占AChE阳性神经元总数的39%。这些结果为研究Alzheimer'sdisease病理过程中基底前脑隔区胆碱能神经元退变与NO的关系提供了形态学依据。  相似文献   

6.
本文利用Northern印迹分析技术研究了完全致癌物二甲基苯蒽(DMBA)对小鼠表皮鸟氨酸脱羧酶(ODC)mRNA和转化生长因子β(TGF-β)mRNA水平的影响。DMBA在15μg和900μg剂量下一次涂用于小鼠皮肤,可使表皮ODCmRNA和TGF-βmRNA表达增加。ODCmRNA为单一的2.0kb大小的条带,其表达在在36h时最为明显。而TGF-βmRNA大小为2.5kb和1.9kb,其表达在36h时最高,到48h几乎降至正常,但在72h又有增加。ODC和TGF-β可能在DMBA诱癌过程中起重要作用。  相似文献   

7.
人脑源性神经营养因子cDNA在COS7细胞中的表达及活性研究   总被引:4,自引:0,他引:4  
本文从质粒M13mp18-hBDNF中酶切回收人脑源性神经营养因子(hBDNF)全长基因,构建真核表达载体pCMV4-hBDNF。利用脂质体的方法转染COS7细胞,对转染后的COS7细胞提取RNA进行狭缝杂交分析和免疫细胞化学反应,分别从转录及翻译水平上检测BDNF基因在COS7细胞中的表达。实验还证实在COS7细胞中表达的hBDNF蛋白可分泌至胞外并可促进中脑黑质细胞的发育和生长,具有良好的生物学活性。  相似文献   

8.
人脑源性神经营养因子cDNA在COS7细胞中的表达及活性…   总被引:1,自引:0,他引:1  
本文从质粒M13mp18-hBDNF中酶切回收入及源性神经营养因子(hBDNF)全长基因,构建真核表达载体pCMV4-hBDNF。利用脂质体的方法转染COS7细胞,对转染后的COS7细胞提取RNA进行狭缝杂交分析和免疫细胞化学反应,分别从转录及翻译水平上检测BDNF基因在COS7细胞中的表达。实验还证实在COS7细胞中表达的hBDF蛋白可分泌至胞外并可促进中脑黑质细胞的发育和生长,具有良好的生物学  相似文献   

9.
Metylomonassp.GYJ3菌的甲烷单加氧酶(MMO)粗酶提取液经DEAE-SepharoseCL-6B阴离子交换层析、SephadexG-100凝胶过滤层析和DEAE-TSKgelHPLC分离纯化出MMO还原酶组分.经HPLC分析,纯度大于95%,纯化倍数为4.4,加入至MMO羟基化酶和调节蛋白B的体系中表现比活为228nmol环氧丙烷每分钟毫克蛋白.SDS-PAGE电泳表明还原酶由一种亚基组成,分子量42kD.ICP-AES测定还原酶的Fe含量为1.83molFe每mol蛋白.UV-Vis光谱表明还原酶除280nm蛋白质特征峰外在460nm有最大吸收峰,且A280nm/A460nm为2.50,与其它黄素一铁硫蛋白相似,推测还原酶可能含一个FAD辅基和Fe2S2中心.在厌氧条件下,还原酶能够和NADH作用,UV-Vis光谱分析表明还原酶460nm处特征吸收峰消失,说明在MMO催化过程中还原酶接受NADH的电子.DEAE-SepharoseCL-6B阴离子交换层析分离出调节蛋白B,部分纯化的调节蛋白B的分子量大约在20kD,它能够提高MMO比活性40倍,MMO还原酶和调节蛋白B单独存在时不具有MMO  相似文献   

10.
池杉┐水稻系统的生态效应(Ⅱ)系统的生态环境效应黄兆祥郑珍贵朱笃(南昌大学生物科学工程系,南昌330047)ECOLOGICALEFFECTOFTAXODIUMASCENDENS-ORYZASATIVAECOSYSTEM(Ⅱ)ECOLOGICAL-...  相似文献   

11.
Previously, there have been conflicts over whether external or internal nutrient concentrations control phytoplankton growth rates at steady state in continuous culture. To experimentally demonstrate that both equations equally describe steady state growth, continuous culture studies with phosphorus-limited growth of the chrysophyte Monochrysis lutheri Droop were carried out over the entire growth rate region up to biomass washout. Data were examined using both the Monod and Droop equations, and, even though there were significant variations in the yield coefficient with growth rate, the data fit both equations reasonably well. Because of their relative simplicity, the Droop equation and an equation combining both the Monod and Droop equations are better suited for expressing kinetic data than the Monod equation. It is crucial, though, that the criteria necessary to achieve steady state be fulfilled.  相似文献   

12.
The benthic diatom, Navicula seminulum var. hustedtii Patr, was isolated from the field and studied in laboratory cultures. Experiments were conducted to determine the suitability of Millipore membranes and solidified agar substrate for diatom colonization under continuous flow conditions. Diatom colonization showed large variation and low reproducibility on Millipore membranes of different materials and pore sizes. Solidified agar substrate supported stable and reproducible colonization and is nutritionally neutral, translucent, homogeneous and easy to sample. The diatom colonization process on agar substrate involved four growth phases: i) pioneer; ii) exponential; iii) steady state; and, iv) vanishing. The culture system was also used in bioassay, testing the toxic effect of copper on the growth of benthic diatoms. The proposed method provides a useful means for studying autecology of benthic diatoms as well as for bioassay work.  相似文献   

13.
To determine how rapidly pulmonary capillaries recruit after sudden changes in blood flow, we used an isolated canine lung lobe perfused by two pumps running in parallel. When one pump was turned off, flow was rapidly halved; when it was turned on again, flow immediately doubled. We recorded pulmonary capillary recruitment in subpleural alveoli using videomicroscopy to measure how rapidly the capillaries reached a new steady state after these step changes in blood flow. When flow was doubled, capillary recruitment reached steady state in <4 s. When flow was halved, steady state was reached in approximately 8 s. We conclude that the pulmonary microcirculation responds rapidly to step changes in flow, even in the capillaries that are most distant from the hilum.  相似文献   

14.
SUMMARY: Comparisons are given of the output of sorbose from 3 litre cultures of Acetobacter suboxydans grown in a sorbitol medium in batch and continuous culture. An estimate is given of the investment value of a continuous process of sorbose production relative to the batch process.  相似文献   

15.
Sustained oscillations in cell concentration, average per cell DNA content, and average cell size were found in continuous photoautotrophic cultures of Chlorella vulgaris at low dilution rates (0.1/day). The period of oscillation was approximately 10 days. DNA histograms determined by flow cytometry exhibited reproducible pattern through consecutive oscillations. At the maximum cell concentration during an oscillation, the DNA histograms showed that the majority of the cells were not replicating their chromosomes, and most of the culture was comprised of single cells in G0/G1 phase. The cells then initiated DNA replication; however, because of the long generation time, the cell concentration decreased to a minimum, and at the same time the average per cell DNA content reached its maximum value. At this point the cells began to divide, and the cell concentration increased until it reached its maximum value at the beginning of the next oscillation. Calculations based on the supplied nutrients and comparison to biomass generation showed that the oscillatory behavior in continuous photoautotrophic cultures of C. vulgaris was not due to nutrient limitation, but most likely was due to the secretion of compounds that alter cell cycle kinetics. The oscillatory behavior disappeared when the dilution rate was increased to 0.3/day and the culture reached a stable steady state.  相似文献   

16.
Haemopoiesis continued for over 2 months in organ culture of embryonal mouse liver, and haemopoietic stem cells (CFUs) capable of DNA-synthesis were found in it all that time. Between the 10th and 40th day the number of stem cells in the culture was sustained in a steady state. Both in normal and in regenerating adult bone marrow haemopoiesis ceased within a short time in the culture. Induction of proliferation in haemopoietic stem cells combined with undamaged or improved micro-environment resulted in a little better maintenance of CFUs in the adult bone marrow culture, The results are discussed in the light of current concepts of haemopoietic stem cell regulation.  相似文献   

17.
SUMMARY: A filamentous mould was cultured by the continuous flow method in which medium is supplied at a constant rate and the culture volume is kept constant. Flow rates up to 0·1 culture volumes/hr were used. The mycelial dry weight concentration and the yield of mycelium/g of carbon source used were equal to or slightly greater than the maximum obtained in batch culture. With glucose concentrations up to 80 g/1. at a flow rate of 0·05 culture volumes/hr, about 45% of the substrate carbon was converted into mycelial carbon and the remainder oxidized to CO2.
With unlimited amounts of all nutrients available growth of the mould followed the exponential law, as does bacterial growth, and therefore the mould had a constant doubling time.
The oxygen demand of the mould as function of growth rate was determined.
Conditions were found under which the rate of penicillin production/g of mycelium remained at its maximum value for 1000 hr.  相似文献   

18.
Information on the nutrient kinetics of Asterionella formosa Hass. and Cyclotella meneghiniana Kutz. under either phosphate or silicate limitation was obtained for use in a Monod model and in a variable internal stores model of growth. Short-term batch culture growth experiments were fit to the Monod model and long-term semicontinuous culture experiments and short-term uptake experiments were fit to the variable internal stores model. Mathematical analysis indicates that the parameters of the 2 models may be expressed in terms of each other at steady state. The qualitative results of both batch and steady state culture methods agree. For limiting phosphate experiments. A. formosa is better able to grow at low PO4-P concentrations than C. meneghiniana, as shown by its lower K for PO4-P limited growth. The kQ of A. formosa compared to C. meneghiniana found in long-term semicontinuous culture indicates that A. formosa is almost an order of magnitude more efficient at using internal phosphate for growth. The qualitative results under silicate-limited growth of C. meneghiniana is less than that of A. formosa. The kQ from semicontinuous culture experiments indicates that C. meneghiniana is the more efficient at using internal silicate for growth. Nutrient uptake experiments showed more variability from a Michaelis-Menten relationship than short-term growth experiments. There were no significant differences between the 2 species in half saturation constants for either phosphate or silicate uptake. We observed a marked dependence of the coefficient of luxury consumption (R) of phosphate on the steady state growth rate. A. formosa has a higher R than C. meneghiniana.  相似文献   

19.
In a cytostat, a continuous culture is monitored and controlled by an automated flow cytometer system, based on the determination of the cell concentration and the single cell property distribution of the growing cell population. The growing culture can be maintained at steady state even at such low cell concentrations that the bioreactor medium composition is negligibly changed by the few cells. Therefore, the cell environment is precisely defined by the feed composition since products of cell growth are not present in significant amounts. Effects on cell growth of nutrients, of toxic compounds such as drugs, or of products made by the cells, if added to the feed medium, can be readily isolated. Using the cytostat, it is shown here that ethanol assumes the triggering function for the increase in cell size in Saccharomyces cerevisiae normally only seen at critical growth rates above critical cell densities. This suggests that ethanol assumes a quorum sensing function on cell growth when a critical cell density is reached.  相似文献   

20.
采集并组织分离到假褐云斑鹅膏Amanita pseudoporphyria的纯培养菌丝。培养发现其在琼脂培养基上生长形态与一般蕈菌有差别。摇瓶液体培养条件下,假褐云斑鹅膏菌丝体干重为0.626g/L,在气升式反应器内假褐云斑鹅膏菌丝体干重可达到1.629g/L。反应器培养的菌丝体毒素的HPLC分析表明菌丝体内含有鹅膏毒肽,而不含有鬼笔毒肽。结果表明可以通过液体培养鹅膏菌丝体来生产鹅膏毒素。  相似文献   

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