氨基酸的分子结构与遗传密码简并及二维集合分类

根据氨基酸遗传密码子的简并程度,可将64个遗传密码子分为高简并度类（3,4,6度简并组）和低简并度类（1,2度简并组）两大类。高简并度类有9个氨基酸,其分子量比较小,等电点的分布比较集中。低简并度类有11个氨基酸,其分子结构比较复杂,参考Taylor对氨基酸特性的分类图,本文提出以分子量（M）及等电点（P）作为氨基酸的化学特性坐标,作出其二维集合MP分类图,MP分类图可以反映出氨基酸的各种属性,如分子量的大小,简并度的高低,极性与非极性、带电荷或不带电荷,疏水性与亲水性,以及氨基酸残基的种类等。根据氨基酸的分类分析,可以认为：高简并度氨基酸多数是脂烃类和羟脂烃类的氨基酸,分子量比较小,分子结构比较简单,大部分为疏子性,主要组成跨膜结构或蛋白质的结构域,可能是出现较早的氨基酸;而低简并度的氨基酸,分子结构比较复杂,分子量比较大,多数是和蛋白质功能有密切联系的基团,可能是进化出现较晚的结构。     

基于AHP与Rough Set的农业节水技术综合评价

由于不同区域自然条件的差异,农业节水技术自身特点及对应用环境条件的要求,导致不同农业节水技术的应用效果存在很大差异,有较大的不确定性,因此,如何筛选合理的评价指标,构建科学、全面的农业节水技术综合评价方法具有十分重要的意义。根据对农业节水技术应用效果的实地调研,应用Delphi法从调查获得的20项评价指标中筛选出了9项农业节水技术综合评价指标。其中节水率、积温和土壤肥力属于生态因子,产投比、劳动力投入和经济投入属于经济因子,可靠性、推广程度和农民认可度为社会因子。基于以上9项指标,构建了农业节水技术综合评价指标体系.综合评价方法(ARM)通过引入经验因子α对应用层次分析法(AHP)和粗糙集(Rough Set)所获得指标权重进行修订,使指标权重更加合理化。同时,分别应用AHP、Rough Set和ARM对甘肃省武威市的地膜覆盖、秸秆覆盖和常规畦田灌溉在大田中的应用效果进行了综合评价。评价结果显示,在对地膜覆盖技术评价中,AHP法过分强调了经济效益的作用(0.44),Rough Set法则强调的是生态效益(0.33)和社会效益(0.32),弱化了经济效益(0.05),ARM修正了以上2种方法的评价结果,获得地膜覆盖的经济效益、生态效益和社会效益,分别为0.36、0.20和0.13。在对秸秆覆盖评价中,与其它两种方法相比,Rough Set法的评价结果存在显著性差异,ARM修正获得的经济效益、生态效益和社会效益,分别为0.09、0.18和0.06。在对常规畦田灌溉评价中,Rough Set法强调了生态效益(0.28),经过修正获得的经济效益、生态效益和社会效益,分别为0.24、0.01和0.13。ARM的评价结果表明,采用地膜覆盖的经济效益最佳;同常规畦田灌溉相比较,地膜覆盖、秸秆覆盖的生态性指数分别比之高0.19和0.17,主要是由于秸秆覆盖具有保墒、增加土壤有机质以及在作物生长后期调节地温的作用,地膜覆盖具有节水、提高苗期土壤温度和促进提前出苗的作用;同秸秆覆盖相比,地膜覆盖和常规畦田灌溉的社会性指数分别高112.12%、18.18%,说明这两种技术在河西半干旱地区具有良好的社会基础。可见,在西北半干旱地区地膜覆盖用于种植玉米的效果最佳,而秸秆覆盖尽管其生态效益较高,但经济效益较低,推广应用存在一定的难度。     

Spp1 at the crossroads of H3K4me3 regulation and meiotic recombination

In Saccharomyces cerevisiae, all H3K4 methylation is performed by a single Set1 Complex (Set1C) that is composed of the catalytic (Set1) and seven other subunits (Swd1, Swd2, Swd3, Bre2, Sdc1, Spp1 and Shg1). It has been known for quite some time that trimethylated H3K4 (H3K4me3) is enriched in the vicinity of meiotic double-strand breaks (DSBs), but the link between H3K4me3 and the meiotic nuclease Spo11 was uncovered only recently. The PHD-containing subunit Spp1, by interacting with H3K4me3 and Mer2, was shown to promote the recruitment of potential meiotic DSB sites to the chromosomal axis allowing their subsequent cleavage by Spo11. Therefore, Spp1 emerged as a key regulator of the H3K4 trimethylation catalyzed by Set1C and of the formation of meiotic DSBs. These findings illustrate the remarkable multifunctionality of Spp1, which not only regulates the catalytic activity of the enzyme (Set1), but also interacts with the deposited mark, and mediates its biological effect (meiotic DSB formation) independently of the complex. As it was previously described for Swd2, and now for Spp1, we anticipate that other Set1C subunits, in addition to regulating H3K4 methylation, may participate in diverse biological functions inside or outside of the complex.     

一种改进的图象模糊增强技术

本文简要地讨论了传统模糊增强算法的原理,并详细讨论了这种算法所存在的缺陷。针对传统模糊增强算法的缺陷,本文提出了一种改进的模糊增强算法。实验证明,改进的的算法在图象的处理质量上得到了提高。     

circRNA-associated ceRNA network construction reveals the circRNAs involved in the progression and prognosis of breast cancer

Recently, increasing evidences show that circular RNAs (circRNAs) are important regulators of various diseases, especially cancer. However, the regulatory role and the potential mechanism of action of circRNAs in breast cancer remain largely unknown. In this study, weighted gene co-expression network analysis was conducted with the differentially expressed miRNAs and mRNAs in breast cancer from The Cancer Genome Atlas database to identify the key modules associated with the carcinogenesis of breast cancer. In the significant turquoise and brown modules, 22 miRNAs and 1877 mRNAs were identified, respectively. Then, We compared and predicted the target genes and performed survival analysis to identify the miRNAs and mRNAs related to the prognosis of breast cancer. A circRNA-related competitive endogenous RNA network was identified by database co-screening, and deleted in liver cancer 1 (DLC1) was identified as a key gene. Finally, to assess how genes in key modules and key genes contribute to the development of breast cancer, relevant pathway information was obtained through DAVID and Gene Set Enrichment Analysis. These data demonstrated that three circRNAs (hsa-circ-0083373, hsa-circ-0083374, and hsa-circ-0083375) that regulate DLC1 expression via hsa-mir-511 and are involved in the pathogenesis and development of breast cancer.     

The Set1/COMPASS Histone H3 Methyltransferase Helps Regulate Mitosis With the CDK1 and NIMA Mitotic Kinases in Aspergillus nidulans

Mitosis is promoted and regulated by reversible protein phosphorylation catalyzed by the essential NIMA and CDK1 kinases in the model filamentous fungus Aspergillus nidulans. Protein methylation mediated by the Set1/COMPASS methyltransferase complex has also been shown to regulate mitosis in budding yeast with the Aurora mitotic kinase. We uncover a genetic interaction between An-swd1, which encodes a subunit of the Set1 protein methyltransferase complex, with NIMA as partial inactivation of nimA is poorly tolerated in the absence of swd1. This genetic interaction is additionally seen without the Set1 methyltransferase catalytic subunit. Importantly partial inactivation of NIMT, a mitotic activator of the CDK1 kinase, also causes lethality in the absence of Set1 function, revealing a functional relationship between the Set1 complex and two pivotal mitotic kinases. The main target for Set1-mediated methylation is histone H3K4. Mutational analysis of histone H3 revealed that modifying the H3K4 target residue of Set1 methyltransferase activity phenocopied the lethality seen when either NIMA or CDK1 are partially functional. We probed the mechanistic basis of these genetic interactions and find that the Set1 complex performs functions with CDK1 for initiating mitosis and with NIMA during progression through mitosis. The studies uncover a joint requirement for the Set1 methyltransferase complex with the CDK1 and NIMA kinases for successful mitosis. The findings extend the roles of the Set1 complex to include the initiation of mitosis with CDK1 and mitotic progression with NIMA in addition to its previously identified interactions with Aurora and type 1 phosphatase in budding yeast.     

Resetting blood pressure by a closed-loop implanted chip system in normotensive rats

A closed-loop implanted chip system was designed to control blood pressure without using drugs. The chip system instantaneously reset blood pressure by stimulating the left aortic depressor nerve according to the feedback signals of arterial blood pressure. The relationship between pressure signals and frequency of stimulation was identified in vitro and in vivo, and the efficiency of the chip system was evaluated in normal anesthetized Wistar rats. To determine whether the depressor effect of the chip was primarily independent on the bradycardia induced by the resetting, the effects of methyl atropine (1.5 g/kg, iv.) and bilateral vagotomy on depressor effect induced by the chip system were determined, respectively. The results indicated that the chip system worked well. The frequency of stimulus linearly increased following the elevation of pressure from 70 to 160 mm Hg. The frequency of the stimulus reached its maximum (100 Hz) when pressure exceeded 160 mm Hg, and the stimulation stopped when MAP was below 70 mm Hg. There were significant decreases in mean arterial pressure (MAP, -20.0+/-4.4 mm Hg) and heart rate (HR, -43.0+/-10.5 bpm) during the resetting in rats. After resetting, both MAP and HR recovered in a minute without any significant rebound. Pretreatment with either methyl atropine or bilateral vagotomy abolished the bradycardia effect but produced no significant effect on hypotension. The results demonstrated that the chip system successfully reset blood pressure in rats, and that the hypotension induced by the chip system was primarily independent on the bradycardia effect.