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1.
INTRODUCTIONCiliaryneurotrophicfactor (CNTF)isanat urallyoccurringproteinwithamolecularmassofapproximately 2 2kDa .Itisexpressedinglialcellswithinthecentralandperipheralnervoussystems.CNTFstimulatesgeneexpression ,cellsurvivalordifferentiationinavarietyof… 相似文献
2.
简要介绍了霍乱毒素B亚单位（CTB）佐剂的作用方式、免疫途径及CTB－融合蛋白的免疫原性，大量实验证据表明，CTB是一种具有良好应用前景的粘膜免疫佐剂。 相似文献
3.
Two heterologous expression systems using thioredoxin (trxA) as a gene fusion part in Escherichia coli were developed to produce recombinant pediocin PA-1. Pediocin PA-1 structural gene pedA was isolated from Pediococcus acidilactici PA003 by the method of polymerase chain reaction (PCR), then cloned into vector pET32a(+), and expressed as thioredoxin-PedA
fusion protein in the host strain E. coli BL21 (DE3). The fusion protein was in the form of inclusion body and was refolded before purification by nickel-iminodiacetic
acid (Ni-IDA) agarose resin column. Biological activity of recombinant pediocin PA-1 was analyzed after cleavage of the fusion
protein by enterokinase. Agar diffusion test revealed that 512-arbitrary unit (AU) recombinant pediocin PA-1 was obtained
from 1 ml culture medium of E. coli (pPA003PED1) using Listeria monocytogenes as the indicator strain. Thioredoxin-PedA fusion gene was further cloned into pET20b(+). Thioredoxin-PedA fusion protein
was detected in both the periplasmic and cytoplasmic spaces. The recombinant pediocin PA-1 from the soluble fraction attained
384 AU from 1 ml culture medium of E. coli (pPA003PED2). Therefore, biologically active pediocin PA-1 could be obtained by these two hybrid gene expression methods. 相似文献
4.
研究用亲和融合谷胱甘肽 S 转移酶 (GST)的方法纯化重组人白细胞介素 6(IL 6)的发酵和纯化工艺 ,使用含有质粒pHZl818的E .coliJMl0 9在 2XYT培养基中进行发酵表达 ,IL 6表达为与谷胱甘肽 S 转移酶 (GST)融合的融合蛋白GST IL 6.融合蛋白存在可溶的活性蛋白和不可溶的包含体两种形式 ,此包含体无活性且无法复性 ,无法用亲和层析回收 ,通过实验优化摇床发酵的诱导温度和转速 ,以增加可溶融合蛋白的表达 .菌体超声破碎液后 ,上清液用作亲和柱层析 ,可将融合蛋白提纯至 80 00 ,每升发酵液可得 10mg融合蛋白 ,用凝血酶裂解处理 6h ,亲和标志物GST被特异性切除 ,裂解得到的IL 6用离子交换柱层析可纯化至 95 00 ,MTT法测得纯化的IL 6生物学活性为 1.0 2× 10 8IU/mg . 相似文献
5.
Wang Guan Hao Mingyue Liu Qiong Jiang Yanlong Huang Haibin Yang Guilian Wang Chunfeng 《Journal of Zhejiang University. Science. B》2021,22(5):348-365
This study probed the protective effect of recombinant Lactobacillus plantarum against hydrogen peroxide(H_2O_2)-induced oxidative stress in human umbilical vein endothelial cells(HUVECs). We constructed a new functional L. plantarum(NC8-p SIP409-alr-angiotensin-converting enzyme inhibitory peptide(ACEIP)) with a double-gene-labeled non-resistant screen as an expression vector. A 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2 H-tetrazolium bromide(MTT) colorimetric assay was carried out to determine the cell viability of HUVEC cells following pretreatment with NC8-p SIP409-alr-ACEIP. Flow cytometry(FCM) was used to determine the apoptosis rate of HUVEC cells. Cysteinyl aspartate specific proteinase(caspase)-3/8/9 activity was also assayed and western blotting was used to determine protein expression of B-cell lymphoma 2(Bcl-2), Bcl-2-associated X protein(Bax), inducible nitric oxide synthase(i NOS), nicotinamide adenine dinucleotide phosphate oxidase 2(gp91 phox), angiotensin II(Ang II), and angiotensin-converting enzyme 2(ACE2), as well as corresponding indicators of oxidative stress, such as reactive oxygen species(ROS), mitochondrial membrane potential(MMP), malondialdehyde(MDA),and superoxide dismutase(SOD). NC8-p SIP409-alr-ACEIP attenuated H_2O_2-induced cell death, as determined by the MTT assay. NC8-p SIP409-alr-ACEIP reduced apoptosis of HUVEC cells by FCM. In addition, compared to the positive control, the oxidative stress index of the H_2O_2-induced HUVEC(Hy-HUVEC), which was pretreated by NC8-p SIP409-alr-ACEIP, i NOS,gp91 phox, MDA, and ROS, was decreased obviously; SOD expression level was increased; caspase-3 or-9 was decreased, but caspase-8 did not change; Bcl-2/Bax ratio was increased; permeability changes of mitochondria were inhibited; and loss of transmembrane potential was prevented. Expression of the hypertension-related protein(Ang II protein) in HUVEC cells protected by NC8-p SIP409-alr-ACEIP decreased and expression of ACE2 protein increased. These plantarum results suggested that NC8-p SIP409-alr-ACEIP protects against H_2O_2-induced injury in HUVEC cells. The mechanism for this effect is related to enhancement of antioxidant capacity and apoptosis. 相似文献
6.
Leaf senescence is often caused by water deficit and the chimeric gene PSA612-1PT is an auto-regulated gene delaying leaf senescence. Using in vitro leaf discs culture system, the changes of contents of chlorophylls, carotenoids, soluble protein and thiobarbituric acid reactive substance （TBARS） and antioxidant enzymes activities were investigated during leaf senescence of PSA612-1PT modified gerbera induced by osmotic stress compared with the control plant （wild type）. Leaf discs were incubated in 20%, 40% （w/v） polyethylene glycol （PEG） 6 000 nutrient solution for 20 h under continuous light [ 130 μmol/（m^2·s）]. The results showed that the contents of chlorophylls, carotenoids and soluble protein were decreased by osmotic stress with the decrease being more pronounced at 40% PEG, but that, at the same PEG concentration the decrease in the transgenic plants was significantly lower than that in the control plant. The activities of superoxide dismutase （SOD）, catalases （CAT）, ascorbate peroxidase （APX）, guaiacol peroxidase （GPX） and dehydroascorbate reductase （DHAR） were stimulated by PEG treatment. However, the increases were higher in PSA612-IPT transgenic plants than in the control plants, particularly at 40% PEG treatment. Lipid peroxidation （TBARS content） was increased by PEG treatment with the increase being much lower in transgenic plant than in the control plant. It could be concluded that the increases in the activities ofantioxidant enzymes including SOD, CAT, APX, GPX and DHAR were responsible for the delay of leaf senescence induced by osmotic stress. 相似文献
7.
Objective: The aims of this research were to purify and identify the 130 kDa (CagA) protein ofH. pylori clinical isolate HP97002 and evaluate the relationships between the purified 130 kDa (CagA) protein and gastric diseases.
Methods: The procedure for isolating the protein included 6 mol/L guanidine extract, size exclusion chromatography and elusion
from gel. Sera of 68 patients with gastric diseases (44 with chronic gastritis, 15 with atrophic gastritis, 7 with peptic
ulcer disease, 2 with gastric cancer) were obtained, and the serological response to CagA was studied by Western-blot using
the purified protein. Results: The purified protein was 130 kDa and preserved good antigenicity and revealed basic isoelectric
point about of 8.1. Among 68 sera, 43 sera could recognize the purified protein associated with chronic gastritis 47.7% (21/44),
atrophic gastritis 86.7% (13/15), peptic ulcer disease 100% (7/7), gastric cancer 100% (2/2). Compared with each other, the
difference was significant (χ2=13.327,P=0.004), and 130 kDa (CagA) protein was associated with severe gastric diseases (r
s=0.442,P=0.001). Conclusion: The 130 kDa (CagA) protein was associated with severe gastric diseases.
Project supported by the China Medical Board (96-628) and Zhejiang Province Hygiene Bureau (2000 A055) 相似文献
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Dong-dong Cao Jin Hu Xin-xian Huang Xian-ju Wang Ya-jing Guan Zhou-fei Wang 《Journal of Zhejiang University. Science. B》2008,9(12):964-968
The changes of kernel nutritive components and seed vigor in F1 seeds of sh
2 sweet corn during seed development stage were investigated and the relationships between them were analyzed by time series
regression (TSR) analysis. The results show that total soluble sugar and reducing sugar contents gradually declined, while
starch and soluble protein contents increased throughout the seed development stages. Germination percentage, energy of germination,
germination index and vigor index gradually increased along with seed development and reached the highest levels at 38 d after
pollination (DAP). The TSR showed that, during 14 to 42 DAP, total soluble sugar content was independent of the vigor parameters
determined in present experiment, while the reducing sugar content had a significant effect on seed vigor. TSR equations between
seed reducing sugar and seed vigor were also developed. There were negative correlations between the seed reducing sugar content
and the germination percentage, energy of germination, germination index and vigor index, respectively. It is suggested that
the seed germination, energy of germination, germination index and vigor index could be predicted by the content of reducing
sugar in sweet corn seeds during seed development stages.
Project supported by the National Natural Science Foundation of China (No. 30370911) and Education Department of Zhejiang
Province, China (No. 20070147) 相似文献
9.
Different responses of two Mosla species to potassium limitation in relation to acid rain deposition
Meng Wang Bao-jing Gu Ying Ge Zhen Liu De-an Jiang Scott X. Chang Jie Chang 《Journal of Zhejiang University. Science. B》2009,10(8):563-571
The increasingly serious problem of acid rain is leading to increased potassium (K) loss from soils, and in our field investigation,
we found that even congenerically relative Mosla species show different tolerance to K-deficiency. A hydroponic study was conducted on the growth of two Mosla species and their morphological, physiological and stoichiometric traits in response to limited (0.35 mmol K/L), normal (3.25
mmol K/L) and excessive (6.50 mmol K/L) K concentrations. Mosla hangchowensis is an endangered plant, whereas Mosla dianthera a widespread weed. In the case of M. hangchowensis, in comparison with normal K concentration, K-limitation induced a significant reduction in net photosynthetic rate (P
n), soluble protein content, and superoxide dismutase (SOD) activity, but an increase in malondialdehyde (MDA) concentration.
However, leaf mass ratio (LMR) and root mass ratio (RMR) were changed little by K-limitation. In contrast, for M. dianthera, K-limitation had little effect on P
n, soluble protein content, SOD activity, and MDA concentration, but increased LMR and RMR. Critical values of N (nitrogen):
K and K:P (phosphorus) ratios in the shoots indicated that limitation in acquiring K occurred under K-limited conditions for
M. hangchowensis but not for M. dianthera. We found that low K content in natural habitats was a restrictive factor in the growth and distribution of M. hangchowensis, and soil K-deficiency caused by acid rain worsened the situation of M. hangchowensis, while M. dianthera could well acclimate to the increasing K-deficiency. We suggest that controlling the acid rain and applying K fertilizers
may be an effective way to rescue the endangered M. hangchowensis.
Project supported by the National Natural Science Foundation of China (No. 30570113) and the Research Fund for the Doctoral
Program of Higher Education (No. 20060335008), China 相似文献
10.
目的:研究硝酸钙胁迫下24-表油菜素内酯(EBR)对黄瓜幼苗抗氧化性能及可溶性蛋白表达的影响。方法:通过单因素随机区组设计,从其抗氧化性能及可溶性蛋白表达的变化来探讨EBR对硝酸钙胁迫下黄瓜幼苗的影响。结果:与对照相比,硝酸钙胁迫导致黄瓜幼苗的丙二醛含量及细胞膜透性显著提高了115.1%和105.6%,膜脂过氧化加剧,黄瓜根系中可溶性蛋白含量降低且至少有35种蛋白发生明显变化,而叶片的可溶性蛋白含量升高且至少有29种蛋白发生明显变化;而硝酸钙胁迫下喷施EBR后黄瓜幼苗的SOD、POD、CAT分别比单纯的硝酸钙胁迫增加了20.2%、20.3%、34.4%,并提高了其可溶性蛋白含量及其表达的变化幅度。结论:24-表油菜素内酯可通过调节硝酸钙胁迫下黄瓜幼苗抗氧化性、可溶性蛋白含量及其表达,进而降低其膜脂过氧化程度,以缓解硝酸钙胁迫对植株的伤害。 相似文献
11.
冯航 《西安文理学院学报》2010,(4):16-18
对近年来三叶木通的化学成分和药理作用研究进展进行了综述.结果表明,该植物含有多种化学成分.其中藤茎含有多种齐墩果酸及常春藤皂苷类三萜皂苷;种子脂肪酸含量较高,不饱和脂肪酸含量达70.1%;果实中含有蛋白质、淀粉、可溶性糖、有机酸、氨基酸、矿质元素等化学物质.三叶木通果实不同部位的乙醇提取物对酪氨酸酶活性均有一定的抑制作用.此外,该植物还具有抗炎、利尿、抗菌作用. 相似文献
12.
目的:在大肠杆菌(BL21)中构建可溶性表达的金黄色葡萄球菌B型肠毒素(SEB)受体拮抗剂。方法:首先确定SEB受体桔抗剂的基因序列,然后用含有SEB受体桔抗剂的基因序列重组质粒表达载体PGEX-4T-1转化大肠杆菌BL21(DE3),利用IPTG诱导表达获得蛋白,产物经GST柱纯化后,利用ELISA检测其与SEB的结合能力并进行其体内外药效学实验。结果:该质粒成功转化为可溶性表达,ELISA结果显示表达产物可与SEB特异性结合。结论:本研究成功对SEB受体拮抗剂GST可溶性表达并对其活性进行初步分析。 相似文献
13.
Effect of total dissolved gas supersaturated water on early life of David’s schizothoracin (Schizothorax davidi) 总被引：3，自引：0，他引：3
Rui-feng LIANG Bo LI Ke-feng LI You-cai TUO 《Journal of Zhejiang University. Science. B》2013,14(7):632-639
The effect of total dissolved gas (TDG) supersaturation on fish living downstream of dams is one of the main ecological risks of high dam construction. A strategy for mitigating the negative effects is needed urgently since many high dams are under construction in the upper reaches of the Yangtze River in China. Experiments on the hatching process of David’s schizothoracin were carried out and the results show that the hatching rate decreased with increasing TDG levels, and that most eggs hatched within a very short time in the higher TDG saturation groups. By using a stereomicroscope, damages to the head, yolk sac, body, anus, etc. were found in larvae which hatched in TDG supersaturated water. Results show that the lesion rate increased with increasing TDG levels. Furthermore, 7-d-old David’s schizothoracin were exposed to TDG supersaturated water levels of 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, and 140% for testing their tolerance to TDG supersaturation. We found that the median lethal concentrations (LC50 ) for 13, 14, 20, 35, 52, 73, and 96 h exposure were 138%, 138%, 134%, 130%, 129%, 128%, and 126%, respectively. The median lethal times (LT50 ) were 7.49, 11.04, 19.25, and 35.38 h for exposure to water with TDG levels of 145%, 140%, 135%, and 130%, respectively. 相似文献
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阿尔茨海默病是一种由多种因素引起的神经系统性退化疾病,其表现为β-淀粉样蛋白沉积和Tau蛋白高度磷酸化等。雌激素可以通过抑制天冬氨酸蛋白水解酶（cysteinyl aspartate specific proteinase,caspase）的活性、调节Bcl相关X蛋白（Bcl-associated X protein,Bax）和B淋巴细胞瘤2（B-cell lymphoma 2,Bcl-2）的表达及其比值、提高下丘脑神经元和神经胶质细胞的环磷酸腺苷（cyclic adenosine monophosphate,c AMP）含量、促进c AMP反应元件结合蛋白（c AMP response element-binding protein,CREB）快速磷酸化、影响海马细胞内N-甲基-D-天门冬氨酸（N-methl-D-aspartate,NMDA）受体的表达而抑制神经元的凋亡;雌激素还可通过影响脑源性神经营养因子和突触素,发挥对神经元的直接保护作用。 相似文献
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Objective: The aims of this research were to purify and identify the 130 kDa (CagA) protein of H. pylori clinical isolate HP97002 and evaluate the relationships between the purified 130 kDa (CagA) protein and gastric diseases. Methods: The procedure for isolating the protein included 6 mol/L guanidine extract, size exclusion chromatography and elusion from gel. Sera of 68 patients with gastric diseases (44 with chronic gastritis,15 with atrophic gastritis,7 with peptic ulcer disease,2 with gastric cancer ) were obtained, and the serological response to CagA was studied by Western-blot using the purified protein. Results: The purified protein was 130 kDa and preserved good antigenicity and revealed basic isoelectric point about of 8.1. Among 68 sera, 43 sera could recognize the purified protein associated with chronic gastritis 47.7% (21/44),atrophic gastritis 86.7% (13/15),peptic ulcer disease 100% (7/7),gastric cancer 100% (2/2). Compared with each other, the difference was significant (χ2=13.327, P=0.004), and 130 kDa (CagA) protein was associated with severe gastric diseases (rs=0.442, P=0.001). Conclusion: The 130 kDa (CagA) protein was associated with severe gastric diseases. 相似文献
17.
用半定量RT-PCR和流式细胞术，研究了白血病细胞系KG1a中P2X7受体在基因和蛋白水平的表达。用荧光分光光度计，测定了用激动剂三磷酸腺苷（ATP）和苯甲酰苯甲酸ATP（BzATP）刺激前后细胞内钙离子浓度的变化，证明P2X7受体的功能。结果表明：KG1a细胞表达P2X7受体，且在激动剂的刺激下能引起KG1a细胞通过P2X7受体的胞外钙内流；去除胞外钙离子时，激动剂不能引起胞内钙浓度的升高；提示KG1a细胞表达P2X7受体的基因和功能蛋白，激活该受体引起胞外钙离子的内流。 相似文献
18.
拟青霉（Paecilomyces sp.FLH30）β-1,3（4）-葡聚糖酶可在重组菌BL21（DE3）-pET28a/PsBg16A中表达.首先确定了该酶的细胞表达定位,再研究了诱导温度、诱导剂种类及浓度、诱导起始菌体密度、诱导时间等因素对重组菌生长及目的蛋白表达活性的影响.结果表明,IPTG和乳糖皆可诱导目的蛋白表达,乳糖的诱导效果优于IPTG.在诱导起始OD_（600）为3.2时加入10%乳糖,20℃诱导20 h最适于目的蛋白的表达.表达条件优化后,酶活可达到482.2U/mL. 相似文献
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以铁尾矿砂为原料,用NaOH,HNO3调节pH值,采用熔融-水热两步法制备了铁尾矿砂光催化剂。利用X射线衍射仪、紫外/可见/近红外光谱仪等对铁尾矿砂光催化剂的结构性能进行表征;以罗丹明B溶液为标准降解物,汞灯为光源,探讨在不同pH条件下合成的铁尾矿砂光催化剂的光催化活性。结果表明,铁尾矿砂光催化剂的主要成分为Fe2.35Si0.65O4和NaNO3,且具有良好的光催化效果;在pH 8.5条件下制备的样品具有多孔结构,光催化性能最强;光照120 min时此样品可降解95.1%的罗丹明B溶液;·O2-是光催化反应过程中最主要的氧化活性自由基。 相似文献