Ethanol inhibits insulin expression and actions in the developing brain

Ethanol-induced cerebellar hypoplasia is associated with inhibition of insulin-stimulated survival signaling. The present work explores the mechanisms of impaired insulin signaling in a rat model of fetal alcohol syndrome. Real-time quantitative RT-PCR demonstrated reduced expression of the insulin gene in cerebella of ethanol-exposed pups. Although receptor expression was unaffected, insulin and insulin-like growth factor (IGF-I) receptor tyrosine kinase (RTK) activities were reduced by ethanol exposure, and these abnormalities were associated with increased PTP1b activity. In addition, glucose transporter molecule expression and steady-state levels of ATP were reduced in ethanol-exposed cerebellar tissue. Cultured cerebellar granule neurons from ethanol-exposed pups had reduced expression of genes encoding insulin, IGF-II, and the IGF-I and IGF-II receptors, and impaired insulin- and IGF-I-stimulated glucose uptake and ATP production. The results demonstrate that ethanol inhibits insulin-mediated actions in the developing brain by reducing local insulin production and insulin RTK activation, leading to inhibition of glucose transport and ATP production.Received 30 December 2004; received after revision 1 March 2005; accepted 10 March 2005     

大肠杆菌K12碱性磷酸酶基因的克隆表达

大肠杆菌碱性磷酸酶是同二聚体金属酶，被phoA基因编码．采用PCR方法从大肠杆菌K12中扩增到碱性磷酸酶基因（phoA）．用限制性内切酶BamHI和HindⅢ将片段插入克隆载体pETBlue-2．该基因被重组、转化后在大肠杆菌中经IPTG诱导表达，而后进行SDS-PAGE检测及紫外吸收分析测OD410．克隆得到了phoA基因并实现了蛋白表达，碱性磷酸酶的活性提高了18，3倍，为进行组织化学、免疫印迹、突变分析等工作打下了坚实的基础．     

钒酸盐和脲对锯缘青蟹碱性磷酸酶的抑制作用

钒酸盐（偏钒酸钠、钒酸钠、偏钒酸铵、联吡啶过氧钒酸钠）和脲作为养殖环境的污染物对锯缘青蟹碱性磷酸酶的酶活力有明显的抑制作用,抑制程度随着抑制剂浓度的增大而增强。钒酸盐对酶的抑制类型均为竞争性抑制,而脲为非竞争性抑制;在脲浓度低于７．０ｍｏｌ／Ｌ时,２５℃与脲处理２．５ｈ的酶的抑制失活作用是可逆的。钒酸盐和脲对酶有协同抑制作用。     

Activation of Calf Intestinal Alkaline Phosphatase by Trifluoroethanol

IntroductionAlkaline phosphatase(EC3 .1 .3 .1 ) is a nonspecificphosphomonoesterase that is found in bothprocaryotes and eucaryotes as a dimer withidentical subunits[1] .It belongs to the group ofenzymes attached to the lipid bilayer of membranesby a glycosylphosphatidylinositol anchor[2 4] .Itis ametalloprotein that has two Zn2 +ions and oneMg2 +ion in each active site.Both its catalyticmechanism and structure have been thoroughlystudied and reviewed[5,6 ] .In mammals,alkalinephosphatase is…     

文昌鱼早期发育中两种碱性磷酸酶的表达

以BCIP为底物研究了碱性磷酸酶在文昌鱼胚胎和幼体中的表达图式.在囊胚、原肠胚和神经胚早期(12～13小时)未检测到碱性磷酸酶的特异性表达;到神经胚中期(15小时,约6个体节),碱性磷酸酶在每一体节的中部开始表达,在胚胎中形成3～6个条纹;在18小时神经胚中,碱性磷酸酶在肌节中表达;到24小时在后部内胚层中也开始表达;在36～48小时幼体中,碱性磷酸酶在消化道中强烈表达,但在咽鳃区不表达,同时在肌节中仍有弱的表达.研究表明碱性磷酸酶可能在肌节的发育过程中具有一定作用.碱性磷酸酶在消化道中的表达可能与这一时期消化道开始行使功能有关.为了鉴定文昌鱼碱性磷酸酶的性质,还研究了L-苯丙氨酸对碱性磷酸酶表达图式的影响,结果表明文昌鱼至少存在两种碱性磷酸酶在消化道中表达的一种是肠型的,与脊椎动物碱性磷酸酶可能为同一类型;另一种主要在肌节中表达,可能是组织非特异性的碱性磷酸酶.     

意蜂工蜂酸性磷酸酶的分离纯化及动力学研究

酸性磷酸酶在自然界中分布很广 .从低等生物大肠杆菌、酵母到高等动植物组织、体液以及人类肝脏、前列腺内都发现有ＡＣＰａｓｅ的存在[1～ 3] .目前人们对生物组织ＡＣＰａｓｅ已有相当广泛的研究 .但对昆虫类特别是蜜蜂的ＡＣＰａｓｅ研究报道较少 .为此 ,我们比较了工蜂、蜂蜜、蜂王浆和蜂蛹的ＡＣＰａｓｅ活力大小 ,并对工蜂ＡＣＰａｓｅ在分离纯化的基础上 ,对其动力学特性进行了初步研究 .该结果对于深入探讨蜜蜂在各发育周期内的代谢活动以及该酶的诱导、调节机制具有重要意义 .1　材料和方法1.1　材料鲜雄蜂虫蛹 (8日龄 )、鲜蜂蜜、…     

Activities and properties of calcineurin catalytic domain

Calcineurin (CN) is the only protein phosphatase known to be under the control of calcium (Ca²⁺) and calmodulin (CaM). The enzyme consists of two subunits, the catalytic A subunit of 61 ku (CNA) and a regulatory B subunit of 19 ku (CNB). In this study, we used PCR amplication to construct a truncation consisting of only the CNA catalytic domain. The truncation was induced by IPTG and expressed inE. coli. PNPP was used as a substrate to study the phosphatase activity of the CNA catalytic domain. The findings show that its activity is 20 times greater than CNA in the presence of CNB and CaM. The optimum reaction temperature for the CNA catalytic domain protein is 40°C, and the optimum reaction pH value is 8.0. Mn²⁺ is still an effective activator for the CNA catalytic domain, but its activity is not controlled by Ca²⁺. In the presence of 6 mmol/L Mg²⁺, adding either Ca²⁺ or EGTA did not change the activity of the CNA catalytic domain.     

蛋白丝氨酸/苏氨酸磷酸酶对细胞周期的调节作用及其与肿瘤关系的研究进展

综述蛋白丝氨酸/苏氨酸磷酸酶的分类及其在细胞生长、分化方面的作用,蛋白丝氨酸/苏氨酸磷酸酶对细胞周期调节作用及其与肿瘤的关系研究进展。蛋白丝氨酸/苏氨酸磷酸酶抑制剂的研究有助于我们了解细胞生长、发育、调控的机制,寻找预防和治疗肿瘤的新途径。     

不同蓝莓品种根际phoD基因相关土壤解磷细菌群落结构分析

【目的】研究不同品种兔眼蓝莓(Vaccinium ashei Reade,简称RB)对phoD(碱性磷酸酶基因)相关土壤解磷细菌群落组成的影响,阐明解磷细菌对土壤磷素的转化以及植物生长的意义。【方法】通过对12个兔眼蓝莓品种根际土壤中phoD进行高通量测序,分析phoD基因相关土壤解磷细菌群落的多样性及组成,解析根际解磷细菌与蓝莓品种以及土壤理化性质之间的相互作用关系。【结果】在12个兔眼蓝莓品种中,蓝莓‘森土里昂’(‘Centurion’, RB4)品种具有最高的群落多样性;蓝莓根际phoD基因相关土壤解磷细菌群落核心细菌群由α-变形菌纲根瘤菌目、红螺菌目、β-变形菌纲伯克氏菌目、γ-变形菌纲黄单胞菌目、海洋螺菌目、假单胞菌目和放线菌门链霉菌目组成;蓝莓根际phoD基因相关土壤解磷细菌群落可以分为RBⅠ、RBⅡ两组,其中RBⅠ组的α-变形菌纲细菌相对丰度显著高于RBⅡ组;土壤总磷(TP)和phoD基因相关土壤解磷细菌群落组成是速效磷(AP)的主要影响因素。【结论】蓝莓不同品种和土壤性质对根际phoD基因相关解磷细菌群落丰度有显著影响,而群落多样性则与对照无显著差异,这可为进一步阐明酸性土壤条件下植物和根际解磷细菌之间的共生关系提供有效的数据支持。     

论元代科学技术和元代社会

宋元时期是中国传统科学技术发展的高潮，而元代实堪称为其顶峰。文章探讨了元代科技发展的整体水平，及其与元代社会的政治、经济、哲学思想、文化交流等方方面面的相互关系，从而探讨元代科技发展起伏的社会原因。