胎衣不下奶牛母体胎盘中血管内皮生长因子A异常表达的分析

目的分析胎衣不下(retained fetal membrane,RFM)奶牛母体胎盘组织中血管内皮生长因子A(vascular endothelial growth factor-A,VEGFA)的表达情况。方法提取RFM及胎衣正常排出奶牛母体胎盘组织中的总蛋白,采用荧光定量PCR及Western blot法检测两组奶牛母体胎盘组织中VEGFA的mRNA转录及蛋白表达水平。结果与胎衣正常排出组相比,RFM组奶牛母体胎盘组织中VEGFA的mRNA转录及蛋白表达水平均显著降低,差异均有统计学意义(P 0. 01)。结论发生RFM的奶牛母体胎盘组织中VEGFA表达减少,提示VEGFA可能参与该病的发生发展。     

胎衣不下奶牛母体胎盘组织基质相互作用分子1异常表达分析

目的分析胎衣不下(retained placenta,RP)奶牛母体胎盘组织中基质相互作用分子1(stromal interaction molecule 1,STIM1)的表达变化,探讨STIM1与奶牛胎衣不下的相关性。方法选取年龄、胎次、体重、泌乳量均相近且身体状况良好的的胎衣不下和胎衣正常排出奶牛,分别为R组和N组,收集两组奶牛母体胎盘组织,提取总RNA和蛋白,利用Q-PCR及Western blot法检测STIM1基因转录及蛋白表达水平。结果 R组STIM1基因转录及蛋白表达水平均下调,与N组相比差异有统计学意义(P0.05)。结论下调表达的STIM1可能通过降低胞内Ca2+浓度影响奶牛RP的发生。     

bta-mir-423-5p在胎衣不下奶牛母体胎盘中的差异表达分析及验证

目的分析及验证bta-mir-423-5p在胎衣不下奶牛母体胎盘中的差异表达。方法选取各种因素无明显差异,且排除其他疾病影响的胎衣正常排出奶牛(对照组)和胎衣不下奶牛(试验组)各3头,对照组在奶牛产后胎衣排出后,立即采集母体胎盘组织约150 mg,试验组在奶牛产后12 h,收集母体胎盘组织约150 mg。采用Solexa高通量测序技术对两组母体胎盘组织间bta-mir-423-5p的差异表达进行分析;利用Real-time Q-PCR法进行验证。结果试验组奶牛母体胎盘中bta-mir-423-5p的表达量明显低于对照组(P0.01)。结论 bta-mir-423-5p在胎衣不下奶牛母体胎盘中异常表达,表明其可能参与胎衣不下的发生,为奶牛胎衣不下发病机理的研究提供了实验依据。     

胎衣不下奶牛胎盘组织差异表达蛋白的筛选及鉴定

目的筛选胎衣不下奶牛胎盘组织中的差异表达蛋白,并对其鉴定,为研究奶牛胎衣不下的发生机理和治疗提供依据。方法收集胎衣不下奶牛及胎衣正常排出奶牛胎盘组织各5份,应用双向凝胶电泳(two-dimensional polyacrylamidegel electrophoresis,2D-PAGE)技术对胎盘组织中蛋白进行分离,银染显色后获得差异表达蛋白点,并采用基质辅助激光解析电离飞行时间质谱(matrix-assisted laser desorption/ionization time of flight mass spectrometry,MALDI-TOF-MS)技术对其进行鉴定。结果与胎衣正常排出组相比,胎衣不下组奶牛胎牛胎盘中差异表达蛋白点共240个,其中表达上调蛋白点212个,表达下调蛋白点28个;母体胎盘中差异表达蛋白点共214个,其中表达上调蛋白点134个,表达下调蛋白点80个,共鉴定出5种差异表达蛋白。与胎衣正常排出组相比,胎衣不下组奶牛胎牛胎盘中牛血清白蛋白(bovine serum albumin,BSA)、α-烯醇化酶(Alpha enolase)表达下调,谷胱甘肽转移酶(glutathione transferases,GST)表达上调;母体胎盘中膜联蛋白V(Annexin V)、Alpha enolase和膜联蛋白A2(Annexin A2)表达均上调。结论发现的5种差异表达蛋白可能与奶牛胎衣不下的发生发展相关。     

奶牛胎衣不下与胎儿胎盘中iNOS、eNOS及MMP-2表达的相关性

目的分析奶牛胎衣不下(Retained fetal membranes,RFM)与胎儿胎盘中诱导型一氧化氮合酶(Induction nitric oxid esynthase,iNOS)、内皮型一氧化氮合酶(Endothelial nitric oxide synthase,eNOS)和基质金属蛋白酶-2(Matrix metallopeptidase-2,MMP-2)表达的相关性,探讨RFM发生的分子机制。方法 RT-PCR扩增、克隆产后胎衣正常脱落(No retention of fetal membranes,NRFM)和RFM奶牛胎儿胎盘中iNOS、eNOS和MMP-2基因,以牛β-actin基因为内参,采用荧光定量PCR法检测RFM和NRFM奶牛胎儿胎盘组织中iNOS、eNOS和MMP-2基因表达的差异。结果克隆的iNOS、eNOS和MMP-2基因片段与GenBank中登录的核苷酸序列同源性均达100%。RFM组iNOS基因mRNA的转录水平明显高于NRFM组(P<0.05),eNOS和MMP-2基因mRNA的转录水平则明显低于NRFM组(P<0.05)。结论 iNOS、eNOS和MMP-2基因mRNA的转录水平与RFM的发生密切相关。     

胎衣不下奶牛母体胎盘黏着斑激酶异常表达分析及验证

目的通过对黏着斑激酶(focal adhesion kinase,FAK)在胎衣不下(retained fetal membranes,RFM)奶牛胎盘组织中差异表达的检测及验证,分析FAK在RFM中的作用。方法选取无其他疾病影响的胎衣自然排出组和RFM组奶牛,提取两组奶牛胎盘组织中的总蛋白和总RNA,利用Western blot及荧光定量PCR法对其FAK蛋白及mRNA水平进行检测。结果与胎衣自然排出组相比,RFM组奶牛母体胎盘组织中FAK蛋白及mRNA水平明显降低(P0.05)。结论发生RFM的奶牛母体胎盘中FAK表达下调,提示FAK可能参与该疾病的发生与发展。     

细胞外信号调节激酶的研究进展

细胞外信号调节激酶(extracellular regulated protein kinases,ERK)是含有丝氨酸/苏氨酸残基的蛋白质激酶,目前发现ERK1~ERK5共5个亚族,广泛存在于细胞浆内。ERK是丝裂原活化蛋白激酶(mitogen-activated protein kinases,MAPKs)信号转导系统组成部分之一,ERK信号通路可通过磷酸化多种底物蛋白在细胞生长、分化、应激及凋亡中起重要作用。本文就ERK信号通路在心肌细胞、神经细胞、肿瘤细胞及淋巴细胞中调节作用的研究进展作一综述。     

信号调节蛋白-α基因真核表达质粒的构建及其在A549细胞中的表达

目的构建信号调节蛋白-α(signal regulatory protein-α,SIRP-α)基因真核表达质粒,并于A549细胞中进行表达。方法提取Hep G2细胞总RNA,RT-PCR扩增SIRP-α基因片段,克隆至真核表达载体pc DNA3.1(+)-EGFP中,构建真核表达质粒pc DNA3.1(+)-SIRP-α/EGFP。将重组表达质粒转染A549细胞,转染24 h后,荧光显微镜下观察转染情况;转染48 h后,RT-PCR检测SIRP-α基因的转录水平;转染72 h后,Western blot法检测SIRP-α蛋白的表达。结果经双酶切和测序鉴定真核表达质粒pc DNA3.1(+)-SIRP-α/EGFP构建正确;转染pc DNA3.1(+)-SIRP-α/EGFP的A549细胞于荧光显微镜下可见绿色荧光;RT-PCR检测结果可见243 bp目的条带,Western blot检测显示SIRP-α存在。结论成功构建了真核表达质粒pc DNA3.1(+)-SIRP-α/EGFP,并于A549细胞中有效表达,为进一步研究SIRP-α与肺癌的相关性奠定了基础。     

细胞外调节蛋白激酶1/2磷酸化对嗜心性柯萨奇病毒B3型感染心肌细胞H9C2能力的影响

目的探讨细胞外调节蛋白激酶1/2(extracellular regulated protein kinases 1/2,ERK1/2)磷酸化对嗜心性柯萨奇病毒B3型(coxsackie virus B3,CVB3)感染心肌细胞H9C2能力的影响。方法通过检测CVB3对心肌细胞H9C2的半数感染量(TCID_(50))确定病毒的作用浓度,用该浓度CVB3分别作用心肌细胞H9C2 0、20、40和60 min,检测细胞中ERK1/2的磷酸化情况。将ERK1/2的磷酸化激动剂Ceramide C6作用于H9C2细胞,同时加入CVB3,检测TCID_(50)。结果确定CVB3对H9C2细胞的TCID_(50)为10~(-7.1),该浓度CVB3作用心肌细胞H9C2 40和60 min时,细胞中磷酸化ERK1/2表达量最低,明显低于0 min(P0.01)。加入激动剂Ceramide C6后,CVB3感染心肌细胞H9C2的TCID_(50)为10~(-6.47)。结论 ERK1/2磷酸化可抑制CVB3感染心肌细胞H9C2的能力,本实验为病毒性心肌炎发病机制的研究奠定了基础。     

慢病毒介导siRNA对大鼠脊髓组织细胞外信号调节激酶1/2及核因子E2相关因子2基因的影响

目的评价慢病毒介导细胞外信号调节激酶1/2(extracellular-signal-regulated kinase 1/2,ERK1/2)-si RNA及核因子(nuclear factor,NF)E2相关因子2(NF-E2-related factor 2,Nrf2)-si RNA进入大鼠局部脊髓组织的转染效果。方法采用NYU撞击法构建SD大鼠脊髓损伤模型(模型组),使用微量注射器将含荧光慢病毒载体(LV-Nrf2-RNAi和LV-ERK1/2-RNAi)稀释液注射至其脊髓T10水平背侧深约0.8 mm处,荧光显微镜下观察不同时间点(12 h、24 h、72 h、7 d及14 d)转染效果。以只切除椎板,不打击脊髓的大鼠作为假手术组,在模型组和假手术组中同时设转染组和未转染组。取大鼠脊髓组织,采用RT-PCR及Western blot法检测转染后7 d时ERK1/2及Nrf2基因m RNA转录及蛋白表达水平。结果与假手术组相比,模型组大鼠脊髓组织在慢病毒转染后各时间点均有较强的荧光表达,病毒转染7 d以内,荧光强度与时间呈正相关,在转染7 d后达到高峰。转染7 d后,假手术组与模型组中ERK1/2及Nrf2基因m RNA转录及蛋白表达水平均较未转染组明显降低(P均0.05)。结论慢病毒介导si RNA转染大鼠脊髓组织,能够有效沉默ERK1/2及Nrf2基因的表达。     

High oleic acid oil suppresses lung tumorigenesis in mice through the modulation of extracellular signal-regulated kinase cascade

This study was undertaken to estimate the effect of dietary high oleic acid oil (OA) on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in mice. Diet containing 10% oil was fed to mice through experimental periods. On day 30 after NNK injection (100 mg/kg body weight, i.p.), the treatment increased the level of prostaglandin E₂ (PGE₂) as well as proliferating cell nuclear antigen, a marker of cell proliferation in a high linoleic acid oil (LA)-fed group but not in an OA-fed group. The NNK treatment also induced the activation of an extracellular signal-regulated kinase (Erk) cascade (Erk, Mek and Raf-1) in an LA-fed group. On the other hand, OA feeding abolished the NNK-induced activation of the Erk cascade. In conjugation with these events, OA feeding reduced lung tumor incidence and tumor multiplicity (percentage of mice with tumors) in mice compared with LA feeding at the 20th experimental week. These results suggest that OA suppresses lung tumorigenesis and that this suppression is correlated with the inhibition of PGE₂ production and inactivation of the Erk cascade.     

Docosahexaenoic acid modulates phorbol ester-induced activation of extracellular signal-regulated kinases 1 and 2 in NIH/3T3 cells

Phosphorylation of extracellular signal-regulated kinases (ERK1/ERK2) has been implicated in cell proliferation of mammalian cells. In the present study, we investigated the role of docosahexaenoic acid (DHA) in the modulation of ERK1/ERK2 phosphorylation, stimulated either with phorbol 12-myristate 13-acetate (PMA) or transforming growth factor-alpha (TGFα) in NIH/3T3 cells. We observed that both PMA and TGFα induced ERK1/ERK2 phosphorylation within 5 min of stimulation. PMA acts upstream of MEK and via activation of protein kinase C (PKC), as GF109203X, a potent PKC inhibitor, and U0126, a MEK inhibitor, abolished its actions on ERK1/ERK2 phosphorylation. TGFα did not act via PKC because GF109203X failed to curtail the degree of ERK1/ERK2 phosphorylation in these cells. DHA alone failed to induce the phosphorylation of these mitogen-activated protein (MAP) kinases; however, this fatty acid significantly curtailed the PMA-but not TGFα-induced MAP kinase enzyme activity and phosphorylation in NIH/3T3 cells. Furthermore, we observed that DHA significantly inhibited PMA-induced translocation of two PKC isoforms, PKCα and PKCε, from cytosol to plasma membrane. Interestingly, DHA failed to inhibit the PMA-induced translocation PKCδ isoform in these cells. Furthermore, DHA decreased PMA-induced proliferation of NIH/3T3 cells. In this study, we show for the first time that DHA inhibits MAP kinase (ERK1/ERK2) activation and proliferation of NIH/3T3 cells via its inhibitory action on PKCα and ε isoforms.     

Enhanced heterologous expression of Trichoderma reesei Cel5A/Cel6A in Pichia pastoris with extracellular co‐expression of Vitreoscilla hemoglobin

BACKGROUND

The deficiency of family 5 endoglucanase (Cel5A) and family 6 cellobiohydrolase (Cel6A) has become a key limiting factor on cellulase enzymatic hydrolysis in bioprocessing of cellulosic biomass. To improve the production of Trichoderma reesei Cel5A / Cel6A, a Vitreoscilla hemoglobin (VHb) gene was tried to co‐express extracellularly for the first time with Cel5A / Cel6A in Pichia pastoris GS115.

RESULTS

Newly constructed recombinant of co‐expressing Cel5A / Cel6A extracellularly with VHb was consistent with the single expression at some key variables of culture condition, i.e. inoculum size, initial pH, culture temperature and methanol concentration. Comparing their single expression, the CMCase activity of co‐expressed Cel5A and Cel6A enzymes enhanced by 40% and 30%, respectively. With high‐cell‐density fed‐batch (HCDFB) fermentation, the co‐expressed Cel5A enzyme activity was 366.8 U mL^‐1 with 4.3 g L^‐1 protein content and the Cel6A enzyme activity reached 1.3 U mL^‐1 with 2.23 g L^‐1 protein content. The two co‐expressed enzyme activities were enhanced by 35% and 20%, respectively, compared with the single expression.

CONCLUSION

VHb protein capable of binding oxygen can be successfully co‐expressed extracellularly with other target proteins. The co‐expression of VHb with recombinant Cel5A / Cel6A is efficient at improving oxygen‐limited condition and thus enzyme production in both shake‐flask and HCDFB fermentation. © 2017 Society of Chemical Industry     

小鼠丝氨酸/精氨酸蛋白特异激酶2基因真核重组表达质粒的构建及其对微管蛋白聚合的影响

目的构建小鼠丝氨酸/精氨酸蛋白特异激酶2(serine/arginine-rich protein specific kinase 2,SRPK2)基因(srpk2)的真核重组表达质粒,并分析其对微管蛋白α-Tubulin聚合的影响。方法利用RT-PCR法扩增srpk2的全长cDNA序列,通过分子克隆技术构建真核重组表达质粒pLV-EGFP(2A)Puro-srpk2;在脂质体Lipofectamine 2000的介导下,将真核重组表达质粒及空载体pLV-EGFP2(A)Puro分别转染人胚肾HEK293T细胞,同时设空白对照组(未转染)。采用RT-PCR及Western blot法分别检测HEK293T细胞中srpk2基因mRNA转录及SRPK2蛋白的表达情况;Western blot法分析HEK293T细胞中聚合态和游离态α-Tubulin的含量。结果双酶切及DNA序列鉴定证明真核重组表达质粒pLV-EGFP2(A)Puro-srpk2构建正确,且在HEK293T细胞中实现了srpk2基因过表达。真核重组表达质粒转染组HEK293T细胞中游离态α-Tubulin含量显著低于空载体转染组及空白对照组(P0.05),而聚合态α-Tubulin水平明显高于空载体转染组及空白对照组(P0.05)。结论成功构建了srpk2基因的真核重组表达质粒,SRPK2可促进α-Tubulin微管蛋白聚合。     

Analysis of protein tyrosine kinase inhibitors in recombinant yeast lacking the ERG6 gene

Studies of small-molecule-protein interactions in yeast can be hindered by the limited permeability of yeast to small molecules. This diminished permeability is thought to be related to the unique sterol composition of fungal membranes, which are enriched in the steroid ergosterol. We report the construction of the novel Saccharomyces cerevisiae yeast strain DCY250, which is compatible with yeast two-hybrid-based systems and bears a targeted disruption of the ERG6 gene to ablate ergosterol biosynthesis and enhance permeability to small molecules. The small-molecule inhibitors of protein tyrosine kinases (PTKs) PP1, PP2, herbimycin A, and staurosporine were investigated with yeast tribrid systems that detect the activity of the PTKs v-Abl and v-Src. These tribrid systems function by expression of the PTK, a B42 activation domain fused to the phosphotyrosine-binding Grb2 SH2 domain, a DNA-bound LexA-GFP-(AAYANAA)(4) universal PTK substrate, and a lacZ reporter gene. Yeast genetic systems that lack functional ERG6 were found to be as much as 20-fold more sensitive to small-molecule inhibitors of PTKs than systems with ERG6, and these deficient systems may provide a useful platform for the discovery and analysis of small-molecule-protein interactions.