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.     

Effects of rare earth elements on telomerase activity and apoptosis of human peripheral blood mononuclear cells

To study the effects of rare earth exposure on human telomerase and apoptosis of mononuclear cells from human peripheral blood (PBMNCs). The blood contents of 15 rare earth elements, including La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y, were measured by inductively coupled plasma-mass spectrometry. Telomeric repeat amplification protocol assay and flow cytometer analysis were carried out to analyze the telomerase activity and apoptosis of PBMNCs, respectively. The total content of rare earth elements in the blood showed significant differences between the exposed group and the control group. The rare earth exposure increased the telomerase activity and the percentages of cells in the S-phase and the G₂/M phase in PBMNCs, but it had no effect on the apoptotic rate of PBMNCs. Under the exposure to lower concentrations of rare earth elements, the telomerase activity of PBMNCs in the exposed group was higher than that of the control group, and there was no effect on the apoptotic rate of PBMNCs, but promoted the diploid DNA replication and increased the percentages of G₂/M- and S-phase cells.     

A20 plays a critical role in the immunoregulatory function of mesenchymal stem cells

Mesenchymal stem cells (MSCs) possess an immunoregulatory capacity and are a therapeutic target for many inflammation‐related diseases. However, the detailed mechanisms of MSC‐mediated immunosuppression remain unclear. In this study, we provide new information to partly explain the molecular mechanisms of immunoregulation by MSCs. Specifically, we found that A20 expression was induced in MSCs by inflammatory cytokines. Knockdown of A20 in MSCs resulted in increased proliferation and reduced adipogenesis, and partly reversed the suppressive effect of MSCs on T cell proliferation in vitro and inhibited tumour growth in vivo. Mechanistic studies indicated that knockdown of A20 in MSCs inhibited activation of the p38 mitogen‐activated protein kinase (MAPK) pathway, which potently promoted the production of tumour necrosis factor (TNF)‐α and inhibited the production of interleukin (IL)‐10. Collectively, these data reveal a crucial role of A20 in regulating the immunomodulatory activities of MSCs by controlling the expression of TNF‐α and IL‐10 in an inflammatory environment. These findings provide novel insights into the pathogenesis of various inflammatory‐associated diseases, and are a new reference for the future development of treatments for such afflictions.     

源自大黄鱼肠道柠檬酸杆菌的外切几丁质酶的特性分析（英文）北大核心CSCD

【目的】从饲喂富含几丁质饲料的大黄鱼肠道分离具有几丁质分解功能的菌株并分离鉴定新的几丁质酶。【方法】利用胶体几丁质平板分离饲喂杂鱼的大黄鱼肠道中的几丁质分解菌。对几丁质酶基因chi-X进行了克隆并在大肠杆菌中表达。对CHI-X的酶学性质进行了分析。【结果】从饲喂杂鱼的大黄鱼肠道内容物中分离出1株具有几丁质分解功能的费氏柠檬酸杆菌,其中的几丁质酶基因编码1个含493个氨基酸残基的蛋白,其中包含一个糖苷水解酶18家族催化域。CHI-X对胶体几丁质具有分解功能。最适p H和温度分别是4.0和60°C。CHI-X具有很强的pH稳定性,在pH 3.0–11.0的范围培育1 h仍保留90%左右的活性。Mn^(2+),Li^+和K^+可促进CHI-X酶活,Ag^+对CHI-X有抑制作用。CHI-X对蛋白酶和石斑鱼肠道内容物有较强的抗逆性。CHI-X可分解胶体几丁质为N-乙酰葡萄糖胺和N-乙酰葡萄糖胺二聚体,表明它是一个几丁质外切酶。最后,CHI-X和另一个几丁质酶Chi565表现出酶活性的加和效应。【结论】分离自肠道菌的CHI-X能很好适应海水鱼类的肠道环境,可以作为温水海水养殖鱼类的饲料添加剂使用。     

Design and fabrication development of a micro flow heated channel with measurements of the inside micro-scale flow and heat transfer process

The current work provides a design and fabrication technique for a micro channel system that can provide a uniform heat flux boundary condition on the channel wall and a well insulation on the wall to prevent heat loss from the channel to the outside ambient. Therefore, detailed micro-scale flow and heat transfer process and information along the channel can be studied. Semiconductor sensor material was selected to fabricate both the heaters and the arrays of temperature sensors on a silicon substrate. These heaters and sensors were then moved to a low thermal conductivity epoxy-glass substrate for fabrication of the channel. Design consideration and fabrication techniques involved in this processes will be discussed. A final measurement for the validation of the heaters and the sensors fabricated and a study of the flow friction behavior and the heat transfer coefficient distributions inside the micro channel will be presented. The local Nusselt number distrubution inside the micro channel is reported the first time in the open literature.     

高山被孢霉产花生四烯酸及其遗传改造的研究进展

花生四烯酸作为一种重要的多价不饱和脂肪酸,因其具有多种生理功能而被认为是潜在的食品添加剂和药物。近年来,利用高山被孢霉合成花生四烯酸已成为研究热点。前期相关研究主要集中在菌种选育及发酵调控方面。随着研究的不断深入,关于高山被孢霉合成花生四烯酸的代谢途径的研究取得了较大进展。以下简要概述前期工作进展,着重论述花生四烯酸合成途径的关键酶及其高山被孢霉的遗传改造的研究情况,包括生物合成花生四烯酸代谢途径、关键酶及其应用、高山被孢霉的遗传操作系统的构建以及遗传改造的应用,并对其研究前景进行了展望。     

绵羊肌肉中FAS基因和HSL基因的发育性变化及其对肌内脂肪含量的影响

选取不同日龄的雄性哈萨克羊和新疆细毛羊共54只,屠宰后取背最长肌,用索氏抽提法检测肌内脂肪(intramuscular fat,IMF)含量,用荧光实时定量PCR法检测肌肉脂肪酸合成酶(fatty acid synthase,FAS)和激素敏感脂肪酶(hormone-sensitive lipase,HSL)基因表达的发育性变化,并分析基因表达对肌内脂肪沉积的影响。结果表明:1)随着日龄的增加,雄性哈萨克羊的IMF含量持续上升,各生长时期差异显著(P<0.05),而新疆细毛羊的IMF含量在各生长时期无显著差异(P>0.05)。雄性哈萨克羊的IMF含量30~90日龄期间极显著高于新疆细毛羊(P<0.01)。2)FAS基因mRNA水平在哈萨克羊肌肉中初生时最高(P<0.05),然后随日龄的增加呈下降趋势;在新疆细毛羊肌肉中,FAS mRNA水平表现出"下降-上升-下降-上升"的发育模式,其中60日龄显著高于90日龄(P<0.05),其余日龄之间差异不显著。HSL基因在2品种绵羊肌肉中的表达模式基本类似,在哈萨克羊肌肉中随年龄的增加而下降,初生时的水平显著高于60~90日龄(P<0.05);在新疆细毛羊中30日龄时达到最高(P<0.01),到60日龄时下降到最低(P<0.05),随后保持这种低表达水平。3)FAS和HSL基因mRNA的表达量均与哈萨克羊IMF含量呈负相关,相关系数分别为:r=-0.485(P=0.02),r=-0.423(P=0.05);在哈萨克羊中两基因表达量水平比值(FAS:HSL)与IMF呈极显著负相关r=-0.552(P=0.01)。在新疆细毛羊中两基因的表达水平及比值均与IMF无显著相关性(P>0.05)。     

蓝藻的硫氧还蛋白

蓝藻(蓝细菌)是一种分布广泛,结构简单的原核生物。不象其它的光合细菌,蓝藻含有叶绿素a,并且象真核藻和高等植物一样,以分解水作为光合电子传递的电子源。有许多种蓝藻能够固氮。大多数丝状蓝藻具有营养胞和异形胞。异形胞是厌氧的固氮场所。       

循环包装回收技术在筛选肝癌细胞相关耐药基因中的应用

肝癌先天性多表达多药耐药基因,严重影响肝癌的化疗效果,筛选肝癌细胞中的耐药基因,研究其耐药机制有助于提高肝癌化疗效果,提高肝癌的治愈率。首先构建肝癌细胞逆转录病毒的cDNA文库,感染成纤维细胞,使得逆转录病毒基因整合进细胞,加药筛选,存活细胞中的基因再次包装成病毒,用于下一轮筛选。采用循环包装回收(Cyclical packaging rescue,CPR)技术进行肝癌细胞耐药基因的筛选即是通过病毒包装将基因从细胞中钓取出来,相比于常规筛选方法,仅通过一轮筛选可能会出现很多假阳性基因,采用CPR技术则是通过多轮筛选,很大程度减少了假阳性细胞的出现。通过该方法经过四轮筛选获得核糖体蛋白S11(RPS11)、核糖体蛋白L6(RPL6)、核糖体蛋白L11(RPL11)、核糖体蛋白L24(RPL24)等几种基因,经初步检测,增加了细胞的耐药性。