牙形石Histiodella Hass 四个种的讨论及地层对比意义

作者描述了产自塔里木盆地的HistiodellaHass的四个种,并探讨了它们与中国北方和北美中大陆暖水型牙形石及中国南方和北大西洋冷水型牙形石的对比关系。认为Histiodellasinuosa带对比北美中大陆牙形石动物群3的下部、中国南方Amorphognathusvariabilis带下部和中国北方Aurilobodusleptosomatus-Loxodusdissectus带下部。Histiodellaholodentata带下部相当于中国北方Aurilobodusleptosomatus-Loxodusdissectus带中部或中国南方的Amorphognathusvariabilis带至Eoplacognathussuecicus带的下部。Histiodellakristinae带对比北大西洋区的Eoplacognathussuecicus带中上部和中国北方的Tangshanodustangshanensis带。Histiodellabellburnensis带对比北大西洋区的Eoplacognathussuecicus带的上部到Eoplacognathusfoliaceus带下部。HistiodellaHass与北大西洋区和中国北方区典型牙形石的共同出现可以作为一个桥梁,建立起北美中大陆、北大西洋、塔里木盆地及华北地区牙形石的对比关系。     

Using pseudo-amino acid composition and support vector machine to predict protein structural class

As a result of genome and other sequencing projects, the gap between the number of known protein sequences and the number of known protein structural classes is widening rapidly. In order to narrow this gap, it is vitally important to develop a computational prediction method for fast and accurately determining the protein structural class. In this paper, a novel predictor is developed for predicting protein structural class. It is featured by employing a support vector machine learning system and using a different pseudo-amino acid composition (PseAA), which was introduced to, to some extent, take into account the sequence-order effects to represent protein samples. As a demonstration, the jackknife cross-validation test was performed on a working dataset that contains 204 non-homologous proteins. The predicted results are very encouraging, indicating that the current predictor featured with the PseAA may play an important complementary role to the elegant covariant discriminant predictor and other existing algorithms.     

植物基因打靶技术及其应用

本文对植物基因打靶技术的原理、操作程序、打靶效率的影响因素及其在植物中的应用现状进行了综述,并就如何有效的提高打靶效率提出了建议,同时对该技术在植物学研究领域中的应用前景进行了展望。     

二乔玉兰开花过程中花色变化的生理生化机制

以4年生二乔玉兰不同花期外层花瓣为试材,测定其在开花过程中花瓣色度值、花色苷、类黄酮、可溶性糖含量、细胞pH值以及相关酶活性的变化,以探讨二乔玉兰花色呈色机理。结果显示:(1)随着花期的推移,苯丙氨酸解胺酶(PAL)和查尔酮异构酶(CHI)活性逐渐减弱,细胞pH值逐渐变大,可溶性糖、花色苷、类黄酮含量不断降低,而花瓣明亮度增强,红色度以及彩色度减弱,且不同花期各参数值之间差异显著。(2)花瓣可溶性糖含量、PAL和CHI的活性与其花色素苷、类黄酮含量变化之间呈显著正相关关系,花瓣pH值的变化、明亮度L*值与花色素苷、类黄酮含量之间呈显著负相关,色相值a*与花色苷含量的变化呈显著正相关。研究表明,二乔玉兰花瓣花色苷和类黄酮含量的高低可以影响其花色的深浅,可溶性糖含量、PAL和CHI活性、细胞pH通过参与一定的生理代谢来调节花色素的形成,进而引起二乔玉兰花色色调的改变。     

HILI Inhibits TGF-β Signaling by Interacting with Hsp90 and Promoting TβR Degradation

PIWIL2, called HILI in humans, is a member of the PIWI subfamily. This subfamily has highly conserved PAZ and Piwi domains and is implicated in several critical functions, including embryonic development, stem-cell self-renewal, RNA silencing, and translational control. However, the underlying molecular mechanism remains largely unknown. Transforming growth factor-β (TGF-β) is a secreted multifunctional protein that controls several developmental processes and the pathogenesis of many diseases. TGF-β signaling is activated by phosphorylation of transmembrane serine/threonine kinase receptors, TGF-β type II (TβRII), and type I (TβRI), which are stabilized by Hsp90 via specific interactions with this molecular chaperone. Here, we present evidence that HILI suppresses TGF-β signaling by physically associating with Hsp90 in human embryonic kidney cells (HEK-293). Our research shows that HILI mediates the loss of TGF-β-induced Smad2/3 phosphorylation. We also demonstrate that HILI interacts with Hsp90 to prevent formation of Hsp90-TβR heteromeric complexes, and improves ubiquitination and degradation of TβRs dependent on the ubiquitin E3 ligase Smurf2. This work reveals a critical negative regulation level of TGF-β signaling mediated by HILI (human PIWIL2) by its ability to interact with Hsp90 and promote TβR degradation.     

Development of an Autofluorescent Whole-Cell Biocatalyst by Displaying Dual Functional Moieties on Escherichia coli Cell Surfaces and Construction of a Coculture with Organophosphate-Mineralizing Activity

Surface display of the active proteins on living cells has enormous potential in the degradation of numerous toxic compounds. Here, we report the codisplay of organophosphorus hydrolase (OPH) and enhanced green fluorescent protein (GFP) on the cell surface of Escherichia coli by use of the truncated ice nucleation protein (INPNC) and Lpp-OmpA fusion systems. The surface localization of both INPNC-OPH and Lpp-OmpA-GFP was demonstrated by Western blot analysis, immunofluorescence microscopy, and a protease accessibility experiment. Anchorage of GFP and OPH on the outer membrane neither inhibits cell growth nor affects cell viability, as shown by growth kinetics of cells and stability of resting cultures. The engineered E. coli can be applied in the form of a whole-cell biocatalyst and can be tracked by fluorescence during bioremediation. This strategy of codisplay should open a new dimension for the display of multiple functional moieties on the surface of a bacterial cell. Furthermore, a coculture comprised of the engineered E. coli and a natural p-nitrophenol (PNP) degrader, Ochrobactrum sp. strain LL-1, was assembled for complete mineralization of organophosphates (OPs) with a PNP substitution. The coculture degraded OPs as well as PNP rapidly. Therefore, the coculture with autofluorescent and mineralizing activities can potentially be applied for bioremediation of OP-contaminated sites.     

黄腐酸和甜菜碱预处理对干旱胁迫下平邑甜茶生理特性及光合的影响

该研究以平邑甜茶[Malus hupehensis(Pamp.)Rehd.]2年生实生苗为材料,通过盆栽试验于干旱处理前3d分别连续喷施黄腐酸(FA)、甜菜碱(GB)和复配(FA+GB),并以清水为对照(CK)进行预处理,比较分析不同预处理对干旱胁迫下平邑甜茶的生理及光合特性变化,探讨FA和GB对平邑甜茶的抗旱生理机制。结果显示:(1)与对照相比,FA、GB和FA+GB预处理均能够显著提高平邑甜茶叶片相对含水量,且FA的保水性效果最佳。(2)3种预处理均可显著促进干旱胁迫下叶片可溶性蛋白、可溶性糖和脯氨酸含量增加,且FA+GB预处理后在干旱胁迫下叶片可溶性糖和脯氨酸累积量显著高于单施FA或GB。(3)3种预处理均可显著提高干旱胁迫下平邑甜茶幼苗的SOD、POD、CAT活性,并显著降低MDA的积累速度及其累积量,且以FA+GB预处理的MDA含量最低、抗氧化酶活性最高。(4)GB和FA+GB预处理下平邑甜茶的净光合速率、瞬时水分利用率显著高于CK和FA,且FA+GB处理下改善光合特性的效果最佳,GB次之。研究表明,单独喷施黄腐酸和甜菜碱及两者配施预处理均能够增加干旱胁迫下平邑甜茶的渗透调节物质和相对含水量,提高叶片的保水性,调节抗氧化物酶活性,降低丙二醛含量,增加细胞膜稳定性,改善光合性能,进而提高平邑甜茶的抗旱能力,且以复配喷施(FA+GB)预处理的效果最好。     

Adults scan own- and other-race faces differently

It is well established that individuals show an other-race effect (ORE) in face recognition: they recognize own-race faces better than other-race faces. The present study tested the hypothesis that individuals would also scan own- and other-race faces differently. We asked Chinese participants to remember Chinese and Caucasian faces and we tested their memory of the faces over five testing blocks. The participants' eye movements were recorded with the use of an eye tracker. The data were analyzed with an Area of Interest approach using the key AOIs of a face (eyes, nose, and mouth). Also, we used the iMap toolbox to analyze the raw data of participants' fixation on each pixel of the entire face. Results from both types of analyses strongly supported the hypothesis. When viewing target Chinese or Caucasian faces, Chinese participants spent a significantly greater proportion of fixation time on the eyes of other-race Caucasian faces than the eyes of own-race Chinese faces. In contrast, they spent a significantly greater proportion of fixation time on the nose and mouth of Chinese faces than the nose and mouth of Caucasian faces. This pattern of differential fixation, for own- and other-race eyes and nose in particular, was consistent even as participants became increasingly familiar with the target faces of both races. The results could not be explained by the perceptual salience of the Chinese nose or Caucasian eyes because these features were not differentially salient across the races. Our results are discussed in terms of the facial morphological differences between Chinese and Caucasian faces and the enculturation of mutual gaze norms in East Asian cultures.     

决策失利后情绪的接近性效应与ERP证据

接近性效应是一种决策失利后的情绪体验受实际结果与意愿结果的接近程度影响的现象. 本研究采用事件相关电位(ERP)研究技术, 运用抽奖赌博任务实验范式考察了这一效应. 行为评定结果表明, 被试在实际结果与意愿结果很接近时更可能体验到后悔情绪, 且体验强度较高, 在实际结果与意愿结果相差较远时更可能体验到失望情绪, 且体验强度较低. 脑电结果显示, 接近性主效应在P300上表现显著, 同时, 与接近性的中、远水平条件相比, 近水平条件诱发一个新异晚正成分(LPC). 决策失利后实际结果与意愿结果接近程度不仅影响决策后情绪的性质, 而且调节情绪的强度.