PTP1B选择性抑制剂的分子动力学模拟及结合自由能计算

作为二型糖尿病的潜在治疗药物,蛋白质酪氨酸磷酸酯酶1B（PTP1B）的抑制剂研究一直备受关注。而其中一种二齿类抑制剂由于其普遍较高的选择性和活性,又是抑制剂的研究重点和热点。本文采用分子动力学方法取样,MM/GBSA方法计算了1个二齿类PTP1B抑制剂与PTP1B及其2个同家族酶TCPTP和SHP-2的结合自由能,得到了与实验活性值相符的结果。同时基于MM/GBSA的能量分解计算表明,抑制剂与PTP1B第2位点附近的2个残基ARG24和ARG254有很强的相互作用,与其他2个酶第2位点的相互作用则有所减弱,尤其是SHP-2,几乎没有实质性相互作用。这应该是抑制剂产生选择性的关键。同时活性位点附近的残基PHE182也与抑制剂分子有很强的相互作用,相比TCPTP也有很大优势。希望这些信息在进一步提升PTP1B抑制剂的选择性和活性方面提供帮助。     

蘑菇组织膜—二茂铁修饰的L-酪氨酸传感器

本文采用二茂铁作为电子传递介体,利用蘑菇组织含有丰富的酪氨酸酶,将蘑菇组织肉浆固定在二茂铁(PVC膜)修饰石墨电极上,用电流法测定L-酪氨酸浓度.研究了电极的制备和最佳实验条件,其线性响应范围为2.0×10-4～4.5×10-3 mol.L-1,响应时间小于5 min,电极寿命至少30?d,可用于实际样品分析.,A new approach for assembling amperometric mushroom pulp tissue-based membrane electrode for determination of L-tyrosine analysis is proposed. Ferrocene is used as a mediator of electron transfer between tyrosinase in mushroom tissue and a graphite electrode. The optimal operation conditions are studied. The linear response range of the biosensor is 2.0×10-4to 4.5×10-3mol.L-1 with response time of less than 5 min and lifetime of at least 30 d. The biosensor can be applied to practical sample analysis.     

运动、BDNF与能量代谢平衡的研究进展

脑源性神经营养因子(BDNF)是神经营养因子(NTF)家族的一员。BDNF主要在中枢神经系统内表达,主要分布在海马、杏仁核和皮质,在外周系统心脏、脂肪和骨骼肌也有表达。酪氨酸激酶受体B(tyrosine kinase receptor B,Trk B)是BDNF的特异性高亲和力受体,BDNF可通过与Trk B结合,激发各种信号传导通路而发挥其特殊的生物学功能。脑源性神经营养因子(BDNF)及其受体酪氨酸激酶受体B(Trk B)基因突变或功能缺失均会导致机体能量代谢失衡。BDNF可通过调节神经元的生存、生长并维持其功能在学习和记忆中发挥着重要的作用,BDNF可通过中枢和/或外周的机制调节机体的能量代谢。BDNF是运动预防和治疗人体代谢紊乱的重要因子。运动可以改变中枢神经系统、外周组织细胞内,以及血液BDNF水平。     

FLT3 and NPM1 mutations in Chinese patients with acute myeloid leukemia and normal cytogenetics

Mutations of fms-like tyrosine kinase 3 (FLT3) and nucleophosmin (NPM1) exon 12 genes are the most common abnormalities in adult acute myeloid leukemia (AML) with normal cytogenetics. To assess the prognostic impact of the two gene mutations in Chinese AML patients, we used multiplex polymerase chain reaction (PCR) and capillary electrophoresis to screen 76 AML patients with normal cytogenetics for mutations in FLT3 internal tandem duplication (FLT3/ITD) and exon 12 of the NPM1 gene. FLT3/ITD mutation was detected in 15 (19.7%) of 76 subjects, and NPM1 mutation in 20 (26.3%) subjects. Seven (9.2%) cases were positive for both FLT3/ITD and NPM1 mutations. Significantly more FLT3/ITD aberration was detected in subjects with French-American-British (FAB) M1 (42.8%). NPM1 mutation was frequently detected in subjects with M5 (47.1%) and infrequently in subjects with M2 (11.1%). FLT3 and NPM1 mutations were significantly associated with a higher white blood cell count in peripheral blood and a lower CD34 antigen expression, but not age, sex, or platelet count. Statistical analysis revealed that the FLT3/ITDpositive group had a lower complete remission (CR) rate (53.3% vs. 83.6%). Survival analysis showed that the FLT3/ITD-positive/NPM1 mutation-negative group had worse overall survival (OS) and relapse-free survival (RFS). The FLT3/ITD-positive/NPM1 mutation-positive group showed a trend towards favorable survival compared with the FLT3/ITD-positive/NPM1 mutation-negative group (P=0.069). Our results indicate that the FLT3/ITD mutation might be a prognostic factor for an unfavorable outcome in Chinese AML subjects with normal cytogenetics, while NPM1 mutation may be a favorable prognostic factor for OS and RFS in the presence of FLT3/ITD.     

低振幅振动训练对帕金森小鼠黑质多巴胺能神经元的保护

目的:观察4周低振幅低频振动训练和低振幅高频振动训练对PD模型小鼠黑质区酪氨酸羟化酶(TH)表达和纹状体区脑源性神经营养因子(BDNF)含量的影响,探讨振动训练改善PD模型运动功能的可能作用机制。方法:32只雄性C57BL/6J小鼠随机分为生理盐水(NS)、PD模型、PD+低振幅低频振动训练组(LFV)、PD+低振幅高频振动训练组(HFV),每组6只。后两组鼠分别接受每天低振幅低频、高频振动训练1次,训练4周。经4周干预后,免疫组织化学检测黑质(SNc)区酪氨酸羟化酶(TH)表达变化,酶联免疫法(ELISA)检测纹状体区BDNF含量。结果:PD组黑质区TH阳性细胞数及纹状体区BDNF含量均较NS组明显减少(P<0.01),而LVT组和HVT组其值均较PD组明显增加(P<0.01),后两组与NS组间以上指标无统计学差异。相关分析显示PD模型组黑质区TH细胞计数与纹状体区BDNF含量呈正相关(r=0.970,P<0.01)。结论:振动训练运动方式使基底神经节环路产生适应性调节,利于PD小鼠模型黑质多巴胺能神经元的存活,而上调纹状体区BDNF可能是其作用机制之一。     

酪酪肽与肥胖（综述）

肥胖与许多慢性疾病的发生密切相关,导致其发生的根本原因是能量摄入和代谢失衡。随着对肥胖治疗和研究的不断深入,人们发现了一种与肥胖密切相关的胃肠道激素—酪酪肽（PYY）。酪酪肽主要是由胃肠道粘膜L细胞分泌的一种新的胃肠激素,具有抑制摄食、增加能量消耗、抑制胰岛素分泌的作用。通过对酪酪肽的分布、功能、酪酪肽与肥胖的关系、运动减肥对酪酪肽的影响及其机制的研究,进一步明确酪酪肽的作用途径,为预防和治疗肥胖提供理论参考。     

Adenosine deaminase and protein tyrosine phosphatase activities in liver and peritoneal macrophages of streptozotocin induced diabetic mice

Adenosine deaminase and protein tyrosine phosphatase activities in liver and peritoneal macrophages were estimated in control, streptozotocin induced diabetes and insulin treated diabetic groups of Swiss albino mice. Both the enzyme levels were elevated while glycogen content decreased in the liver of diabetic group of animals as compared to controls, while in insulin treated group, they were comparable to control levels. In macrophages also, both adenosine deaminase which plays an important role in their maturation and protein tyrosine phosphatase enzyme involved in their activation were high in diabetic group, whereas in insulin treated diabetic group, the values were comparable to control levels. *** DIRECT SUPPORT *** A00FN011 00003     

Expression, purification, and bioactivity of GST-fused v-Src from a bacterial expression system

v-Src is a non-receptor protein tyrosine kinase involved in many signal transduction pathways and closely related to the activation and development of cancers. We present here the expression, purification, and bioactivity of a GST （glutathione S-transferase）-fused v-Src from a bacterial expression system. Different culture conditions were examined in an isopropyl ,B-D-thiogalactopyranoside （IPTG）-regulated expression, and the fused protein was purified using GSH （glutathione） affinity chromatography. ELISA （enzyme-linked immunosorbent assay） was employed to determine the phosphorylation kinase activity of the GST-fused v-Src. This strategy seems to be more promising than the insect cell system or other eukaryotic systems employed in earlier Src expression.     

Antioxidant activity and protective effect of Clitoria ternatea flower extract on testicular damage induced by ketoconazole in rats

Background

Ketoconazole (KET), an antifungal drug, has adverse effects on the male reproductive system. Pre-treatments with antioxidant plant against testicular damage induced by KET are required. The flowers of Clitoria ternatea (CT) are proven to have hepatoprotective potential. However, the protective effect on KET-induced testicular damage has not been reported.

Objective

To investigate the protective effect of CT flower extracts with antioxidant activity on male reproductive parameters including sperm concentration, serum testosterone level, histopathology of the testis, and testicular tyrosine phosphorylation levels in rats induced with KET.

Methods

The antioxidant activity of CT flower extracts was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Male rats were treated with CT flower extracts (10, 50, or 100 mg/kg BW) or distilled water via a gastric tube for 28 d (preventive period: Days 1–21) and induced by KET (100 mg/kg BW) via intraperitoneal injection for 7 d (induction period: Days 22–28). After the experiment, all animals were examined for the weights of the testis, epididymis plus vas deferens and seminal vesicle, serum testosterone levels, sperm concentration, histological structures and diameter of testis, and testicular tyrosine phosphorylation levels by immunoblotting.

Results

The CT flower extracts had capabilities for DPPH scavenging and high reducing power. At 100 mg/kg BW, the extract had no toxic effects on the male reproductive system. Significantly, in CT+KET groups, CT flower extracts (50 and 100 mg/kg BW) alleviated the reduction of reproductive organ weight parameters, testosterone levels, and sperm concentration. In addition, CT flower extracts gave protection from testicular damage in KET-induced rats. Moreover, in the CT100+KET group, CT flower extracts significantly enhanced the expression of a testicular 50-kDa tyrosine phosphorylated protein compared with that of other groups.

Conclusions

C. ternatea flower extracts possessing antioxidant activity are not harmful to the male reproductive system and can protect against testicular damage in KET-induced rats.     

3-碘-N-苄氧羰基-L酪氨酸甲酯的合成

以酪氨酸为原料,经酯化、酰胺化、醚化得到N-苄氧羰基-O-甲基甲醚-L酪氨酸甲酯,再经碘代反应得到3-碘-N-苄氧羰基-O-甲基甲醚-L酪氨酸甲酯,最后经Pd/C催化氢化得到3-碘-N-苄氧羰基-L酪氨酸甲酯。主要研究了Pd/C、氢气条件下脱甲基甲醚的方法,该方法反应条件温和,选择性好,后处理简单。