Solution structure and dynamics of human metallothionein-3 (MT-3)

Alzheimer's disease is characterized by progressive loss of neurons accompanied by the formation of intraneural neurofibrillary tangles and extracellular amyloid plaques. Human neuronal growth inhibitory factor, classified as metallothionein-3 (MT-3), was found to be related to the neurotrophic activity promoting cortical neuron survival and dendrite outgrowth in the cell culture studies. We have determined the solution structure of the alpha-domain of human MT-3 (residues 32-68) by multinuclear and multidimensional NMR spectroscopy in combination with the molecular dynamic simulated annealing approach. The human MT-3 shows two metal-thiolate clusters, one in the N-terminus (beta-domain) and one in the C-terminus (alpha-domain). The overall fold of the alpha-domain is similar to that of mouse MT-3. However, human MT-3 has a longer loop in the acidic hexapeptide insertion than that of mouse MT-3. Surprisingly, the backbone dynamics of the protein revealed that the beta-domain exhibits similar internal motion to the alpha-domain, although the N-terminal residues are more flexible. Our results may provide useful information for understanding the structure-function relationship of human MT-3.     

Geranylgeranyl diphosphate synthase in fission yeast is a heteromer of farnesyl diphosphate synthase (FPS), Fps1, and an FPS-like protein, Spo9, essential for sporulation

Both farnesyl diphosphate synthase (FPS) and geranylgeranyl diphosphate synthase (GGPS) are key enzymes in the synthesis of various isoprenoid-containing compounds and proteins. Here, we describe two novel Schizosaccharomyces pombe genes, fps1(+) and spo9(+), whose products are similar to FPS in primary structure, but whose functions differ from one another. Fps1 is essential for vegetative growth, whereas, a spo9 null mutant exhibits temperature-sensitive growth. Expression of fps1(+), but not spo9(+), suppresses the lethality of a Saccharomyces cerevisiae FPS-deficient mutant and also restores ubiquinone synthesis in an Escherichia coli ispA mutant, which lacks FPS activity, indicating that S. pombe Fps1 in fact functions as an FPS. In contrast to a typical FPS gene, no apparent GGPS homologues have been found in the S. pombe genome. Interestingly, although neither fps1(+) nor spo9(+) expression alone in E. coli confers clear GGPS activity, coexpression of both genes induces such activity. Moreover, the GGPS activity is significantly reduced in the spo9 mutant. In addition, the spo9 mutation perturbs the membrane association of a geranylgeranylated protein, but not that of a farnesylated protein. Yeast two-hybrid and coimmunoprecipitation analyses indicate that Fps1 and Spo9 physically interact. Thus, neither Fps1 nor Spo9 alone functions as a GGPS, but the two proteins together form a complex with GGPS activity. Because spo9 was originally identified as a sporulation-deficient mutant, we show here that expansion of the forespore membrane is severely inhibited in spo9Delta cells. Electron microscopy revealed significant accumulation membrane vesicles in spo9Delta cells. We suggest that lack of GGPS activity in a spo9 mutant results in impaired protein prenylation in certain proteins responsible for secretory function, thereby inhibiting forespore membrane formation.     

Three new taxanes with the 10-alkoxy group from the heartwood of Taxus cuspidata

Three novel taxanes with the 10-alkoxy group were isolated from heartwood of Taxus cuspidata. The structures were identified as 2alpha,14beta-diacetoxy-10beta-ethoxytaxa-11,4(20)-dien-5alpha-ol (1), 2alpha,14beta-diacetoxy-10beta-methoxytaxa-11,4(20)-dien-5alpha-ol (2), and 2alpha-acetoxy-10beta-ethoxytaxa-11,4(20)-diene-5alpha,14beta-diol (3) on the basis of spectroscopic analysis. These are the first taxanes with an alkoxy moiety on the skeleton.     

人类驱动结合蛋白及其与某些疾病的相关性

驱动结合蛋白（Kinectin）是真核细胞内生物进化上的保守蛋白质,已发现的功能有（1）与驱动蛋白（Kinesin）相连参与细胞胞吐、胞质运输和有丝分裂等活动;（2）是RhoG蛋白依赖微管的细胞内活动的效应物;（3）是整合素依赖的黏附分子复合体的重要组分;（4）转录延长因子-I通过与驱动结合蛋白结合锚着于内质网,发挥相应的生物学作用。随着研究的深入,发现人类驱动结合蛋白与某些疾病如甲状腺癌、白塞病、再生障碍性贫血、肝细胞癌有一定的相关性。     

Host‐induced gene silencing of an essential chitin synthase gene confers durable resistance to Fusarium head blight and seedling blight in wheat

Fusarium head blight (FHB) and Fusarium seedling blight (FSB) of wheat, caused by Fusarium pathogens, are devastating diseases worldwide. We report the expression of RNA interference (RNAi) sequences derived from an essential Fusarium graminearum (Fg) virulence gene, chitin synthase (Chs) 3b, as a method to enhance resistance of wheat plants to fungal pathogens. Deletion of Chs3b was lethal to Fg; disruption of the other Chs gene family members generated knockout mutants with diverse impacts on Fg. Comparative expression analyses revealed that among the Chs gene family members, Chs3b had the highest expression levels during Fg colonization of wheat. Three hairpin RNAi constructs corresponding to the different regions of Chs3b were found to silence Chs3b in transgenic Fg strains. Co‐expression of these three RNAi constructs in two independent elite wheat cultivar transgenic lines conferred high levels of stable, consistent resistance (combined type I and II resistance) to both FHB and FSB throughout the T₃ to T₅ generations. Confocal microscopy revealed profoundly restricted mycelia in Fg‐infected transgenic wheat plants. Presence of the three specific short interfering RNAs in transgenic wheat plants was confirmed by Northern blotting, and these RNAs efficiently down‐regulated Chs3b in the colonizing Fusarium pathogens on wheat seedlings and spikes. Our results demonstrate that host‐induced gene silencing of an essential fungal chitin synthase gene is an effective strategy for enhancing resistance in crop plants under field test conditions.     

Apple Fruit Diameter and Length Estimation by Using the Thermal and Sunshine Hours Approach and Its Application to the Digital Orchard Management Information System

In apple cultivation, simulation models may be used to monitor fruit size during the growth and development process to predict production levels and to optimize fruit quality. Here, Fuji apples cultivated in spindle-type systems were used as the model crop. Apple size was measured during the growing period at an interval of about 20 days after full bloom, with three weather stations being used to collect orchard temperature and solar radiation data at different sites. Furthermore, a 2-year dataset (2011 and 2012) of apple fruit size measurements were integrated according to the weather station deployment sites, in addition to the top two most important environment factors, thermal and sunshine hours, into the model. The apple fruit diameter and length were simulated using physiological development time (PDT), an indicator that combines important environment factors, such as temperature and photoperiod, as the driving variable. Compared to the model of calendar-based development time (CDT), an indicator counting the days that elapse after full bloom, we confirmed that the PDT model improved the estimation accuracy to within 0.2 cm for fruit diameter and 0.1 cm for fruit length in independent years using a similar data collection method in 2013. The PDT model was implemented to realize a web-based management information system for a digital orchard, and the digital system had been applied in Shandong Province, China since 2013. This system may be used to compute the dynamic curve of apple fruit size based on data obtained from a nearby weather station. This system may provide an important decision support for farmers using the website and short message service to optimize crop production and, hence, economic benefit.     

Rats Generate Vibrissal Sensory Evidence until Boundary Crossing Triggers a Decision

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一种快速鉴别烟粉虱与温室白粉虱成虫的方法——复眼镜检法

介绍能够快速鉴别2种形态相似的重要农业害虫即烟粉虱Bemisia tabaci(Gennadius)和温室白粉虱Trialeurodes vaporariorum(Westwood)成虫的方法——复眼镜检法及其应用。复眼镜检法研究表明,烟粉虱成虫上部复眼、下部复眼之间有一个小眼连接,而温室白粉虱成虫上部复眼、下部复眼是完全分离的。     

海南省昌江发现旧石器

2006年6月,在海南省大广坝水利工程的文物调查中,笔者等在昌江黎族自治县七差乡南阳溪第2级阶地里发现石制品。石制品共计4件;其中,3件出自阶地上部的黄色黏土层中,包括1件石核和2件砍砸器;另1件石核,采集于地表。根据阶地堆积物和器物类型初步判断,石制品的时代为旧石器时代晚期。     

逆转录病毒载体介导的RNA干扰稳定抑制肌肉生长抑制素GDF-8的表达

为将肌肉生长抑制素的干扰序列表达盒hU6-siGDF-8有效导入肌成纤维细胞C2C12中, 以pAV-hU6 + 27载体为基础构建逆转录病毒载体pXSN-hU6-siGDF-8, 并使之与pVSV-G质粒共转染GP-293细胞, 用包装出的病毒粒子感染宿主细胞C2C12, G418筛选稳定整合逆转录病毒的抗性细胞库。2周后, Western Blotting和Real-Time PCR分析结果显示, 细胞内源性的GDF-8基因的表达得到了有效的抑制; MTT法和细胞流式仪分析表明, G418抗性细胞得到了更有效的增殖, 并且G0/G1期细胞数量减少了13.7%, S期细胞数量增加了14.9%。因此, 逆转录病毒载体的RNA干扰系统可以稳定抑制 GDF-8基因表达, 它将成为治疗肌肉萎缩疾病的一个强有力的工具。