骆驼蓬脂转移蛋白基因真核表达载体的构建及其体内外抗瘤效应的研究

目的:构建骆驼蓬脂转移蛋白(lipid transfer protein from Peganum harmala,PhLTP)基因真核表达质粒,并探讨其对黑色素瘤B16细胞在体内外的抗肿瘤作用。方法:将PhLTP基因亚克隆至pcDNA3.1上,获得重组质粒pcDNA3.1-PhLTP;用脂质体转染法将重组质粒及空载体外转染B16细胞,MTT检测其对B16细胞生长的影响。建立B16荷瘤小鼠模型,设重组质粒(pcDNA3.1-PhLTP)、空载(pcDNA3.1)、生理盐水和阳性药物(CTX)组,分别处理小鼠后测量各组肿瘤体积并称瘤重,计算抑瘤率。光镜观察鼠脾、肝等组织变化;免疫组织化学法检测各瘤体中PhLTP、血管内皮生长因子(VEGF)及碱性成纤维细胞生长因子(bFGF)的表达。结果:pcDNA3.1-PhLTP转染B16细胞72 h后,细胞增殖能力明显受到抑制(P0.01)。注射pcDNA3.1-PhLTP组的小鼠肿瘤生长速度明显减慢,肿瘤体积小于空载和生理盐水组(P0.05)。显微镜下可见重组质粒组肿瘤细胞有不同程度的点、片状坏死,而肝、肺等无明显病理损伤。重组质粒组肿瘤组织中有PhLTP蛋白的表达,且VEGF和bFGF的阳性表达指数都低于空载和生理盐水组(P0.01)。结论:成功构建了重组表达质粒pcDNA3.1-PhLTP,体内外实验结果显示其能有效地抑制B16细胞的生长,预示了该重组质粒在治疗黑色素瘤中的潜在应用价值。     

Haloperidol treatment at pre-exposure phase reduces the disturbance of latent inhibition in rats with neonatal ventral hippocampus lesions

Animals with neonatal ventral hippocampal lesions develop during or after adolescence abnormal behaviors related to schizophrenia such as anxiety and latent inhibition disruption. The aim of this study was to test whether haloperidol injection prior to pre-exposure session in the latent inhibition test would facilitate latent inhibition.     

NF-κB的负性调控机制在肿瘤发展与治疗的研究进展

有观点认为肿瘤是一种慢性炎症性疾病。NF-κB作为自然免疫和炎症的重要调节因子及内源性促肿瘤因子,其激活与许多恶性肿瘤的发生和发展密切相关。本文通过对有关NF-κB与肿瘤的文献进行分析,综述了NF-κB信号通路及其负性调控因子对肿瘤的影响的研究进展,从而论证NF-κB与肿瘤的关系以及NF-κB抑制剂在临床治疗中的意义。     

Induction of Oligodendrocyte Differentiation and In Vitro Myelination by Inhibition of Rho-Associated Kinase

In inflammatory demyelinating diseases such as multiple sclerosis (MS), myelin degradation results in loss of axonal function and eventual axonal degeneration. Differentiation of resident oligodendrocyte precursor cells (OPCs) leading to remyelination of denuded axons occurs regularly in early stages of MS but halts as the pathology transitions into progressive MS. Pharmacological potentiation of endogenous OPC maturation and remyelination is now recognized as a promising therapeutic approach for MS. In this study, we analyzed the effects of modulating the Rho-A/Rho-associated kinase (ROCK) signaling pathway, by the use of selective inhibitors of ROCK, on the transformation of OPCs into mature, myelinating oligodendrocytes. Here we demonstrate, with the use of cellular cultures from rodent and human origin, that ROCK inhibition in OPCs results in a significant generation of branches and cell processes in early differentiation stages, followed by accelerated production of myelin protein as an indication of advanced maturation. Furthermore, inhibition of ROCK enhanced myelin formation in cocultures of human OPCs and neurons and remyelination in rat cerebellar tissue explants previously demyelinated with lysolecithin. Our findings indicate that by direct inhibition of this signaling molecule, the OPC differentiation program is activated resulting in morphological and functional cell maturation, myelin formation, and regeneration. Altogether, we show evidence of modulation of the Rho-A/ROCK signaling pathway as a viable target for the induction of remyelination in demyelinating pathologies.     

Interaction of antimicrobial cyclic lipopeptides from Bacillus subtilis influences their effect on spore germination and membrane permeability in fungal plant pathogens

Bacillus subtilis cyclic lipopeptides are known to have various antimicrobial effects including different types of interactions with the cell membranes of plant pathogenic fungi. The various spectra of activities of the three main lipopeptide families (fengycins, iturins, and surfactins) seem to be linked to their respective mechanisms of action on the fungal biomembrane. Few studies have shown the combined effect of more than one family of lipopeptides on fungal plant pathogens. In an effort to understand the effect of producing multiple lipopeptide families, sensitivity and membrane permeability of spores from four fungal plant pathogens (Alternaria solani, Fusarium sambucinum, Rhizopus stolonifer, and Verticillium dahliae) were assayed in response to lipopeptides, both individually and as combined treatments. Results showed that inhibition of spores was highly variable depending on the tested fungus-lipopeptide treatment. Results also showed that inhibition of the spores was closely associated with SYTOX stain absorption suggesting effects of efficient treatments on membrane permeability. Combined lipopeptide treatments revealed additive, synergistic or sometimes mutual inhibition of beneficial effects.     

牙龈卟啉单胞菌血凝素2氯化血红素结合位点多肽对牙龈卟啉单胞菌生长抑制作用

目的探讨牙龈卟啉单胞菌血凝素2（Porphyromonas gingivalis hemagglutinin-2,PgHA-2）的氯化血红素结合位点多肽对牙龈卟啉单胞菌（Porphyromonasgingivalis,Pg）摄取氯化血红素生长的影响。方法合成多肽DHYAVMISK（肽1）,DEYAVMISK（肽2,肽1中第2位氨基酸突变为谷氨酸）,ALHPDHYLI（肽3,HA-2结合位点不相关多肽）。将肽l、肽2、肽3分别与氯化血红素琼脂糖珠预孵育,加入Pg重组血凝素2（Porphyromonas gingivalis recombinant HA-2,PgrHA-2）,收集与氯化血红素结合的PgrHA-2,SDS—PAGE电泳,分析多肽对PgrHA-2与氯化血红素结合的抑制作用。肽1、肽2、肽3与氯化血红素预孵育后,加入到CDC液体培养基中培养Pg,测定菌液A600值,分析多肽对Pg生长的抑制作用。结果肽1浓度依赖性抑制PgrHA-2与氯化血红素结合,而肽2和肽3对PgrHA-2与氯化血红素的结合无抑制作用。在24、48和72h时间点,肽1组的A600值较肽2、肽3和PBS组明显降低（P〈0．05）。结论本研究表明PgHA-2氯化血红素结合位点多肽DHYAVMISK与Pg竞争结合氯化血红素,抑制Pg的生长,为开发新的牙周病防治方法奠定基础。     

衣原体调控宿主细胞凋亡的机制研究进展

衣原体是一类专性细胞内寄生的原核微生物,常引起性传播疾病、失明和肺炎等疾病。衣原体可能已经进化出调控宿主细胞的若干机制,通过改变宿主细胞蛋白位置,干扰宿主细胞凋亡信号通路等来抑制细胞凋亡,维持其自身的存活,核转录因子NF-κB也涉及到衣原体感染细胞凋亡抑制;衣原体可以经半胱氨酸蛋白酶依赖途径等机制诱导细胞凋亡,进而感染邻近细胞。     

重组人睫状神经营养因子的聚乙二醇化修饰简

目的：研究重组人睫状神经营养因子（rhCNTF）突变体的聚乙二醇（PEG）化修饰,对rhCNTF的PEG化产物进行初步分离纯化及相关生物活性检测。方法：采用分子生物学技术经点突变得到rhCNTF的突变体cNm通过实验设计研究CN10的最佳PEG化条件;采用分子筛层析方式对偶联产物进行初步纯化,最后用ELISA和小鼠体重增长抑制法检测PEG化后的CN。。蛋白的生物活性。结果：能运用mPEG—MAL对CN,。进行定点修饰,PEG化后用Superdex200能够分离CN10;PEG化后的CN10每2d腹腔注射1次,对小鼠体重的增长抑制率可达50％,与rhCNTF每天注射2次的体重增长抑制作用相当。结论：CN10蛋白在PEG化修饰后,其减重效应持续时间明显延长。     

Inter-individual variation in reciprocal Ia inhibition is dependent on the descending volleys delivered from corticospinal neurons to Ia interneurons

IntroductionWe investigated the extent to which the corticospinal inputs delivered to Ia inhibitory interneurons influence the strength of disynaptic reciprocal Ia inhibition.MethodsSeventeen healthy subjects participated in this study. The degree of reciprocal Ia inhibition was determined via short-latency (condition-test interval: 1–3 ms) suppression of Sol H-reflex by conditioning stimulation of common peroneal nerve. The effect of corticospinal descending inputs on Ia inhibitory interneurons was assessed by evaluating the conditioning effect of transcranial magnetic stimulation (TMS) on the Sol H-reflex. Then, we determined the relationship between the degree of reciprocal Ia inhibition and the conditioning effect of TMS on the Sol H-reflex.ResultWe found that the degree of reciprocal Ia inhibition and the extent of change in the amplitude of the TMS-conditioned H-reflex, which was measured from short latency facilitation to inhibition, displayed a strong correlation (r = 0.76, p < 0.01) in the resting conditions.ConclusionThe extent of reciprocal Ia inhibition is affected by the corticospinal descending inputs delivered to Ia inhibitory interneurons, which might explain the inter-individual variations in reciprocal Ia inhibition.     

Effect of deglycosylation on the properties of thermophilic invertase purified from the yeast Candida guilliermondii MpIIIa

Invertase from Candida guilliermondii MpIIIa was purified and biochemically characterized. The purified enzyme (INV3a-N) is a glycoprotein with a carbohydrate composition comprising nearly 74% of its total molecular weight (MW) and specific activity of 82,027 U/mg of protein. The enzyme displayed optimal activity at pH 5.0 and 65 ˚C. The Km and V_max values for INV3a-N were 0.104 mM and 10.9 μmol/min/mg of protein, respectively, using sucrose as the substrate. The enzyme retained 50% and 20% of its maximal activity after 168 h and 30 days, respectively, at 50 ˚C. INV3a-N was fully active at sucrose concentrations of 400 mM and the activity of the enzyme dropped slowly at higher substrate concentration. Interestingly, the deglycosylated form of INV3a-N (INV3a-D) displayed 76–92% lower thermostability than that of INV3a-N at all temperatures assayed (50–70 ˚C), and was inhibited at sucrose concentrations of 200 mM. Findings here indicate glycosylation plays an important role, not only in the thermostability of INV3a-N, but also in the inhibition of the enzyme by sucrose. Since the enzyme is active at high sucrose concentrations, INV3a-N may be considered a suitable candidate for numerous industrial applications involving substrates with high sugar content or for improvement of ethanol production from cane molasses.