Evidence from fluid inclusions for microbial methanogenesis in the early Archaean era

Methanogenic microbes may be one of the most primitive organisms, although it is uncertain when methanogens first appeared on Earth. During the Archaean era (before 2.5 Gyr ago), methanogens may have been important in regulating climate, because they could have provided sufficient amounts of the greenhouse gas methane to mitigate a severely frozen condition that could have resulted from lower solar luminosity during these times. Nevertheless, no direct geological evidence has hitherto been available in support of the existence of methanogens in the Archaean period, although circumstantial evidence is available in the form of approximately 2.8-Gyr-old carbon-isotope-depleted kerogen. Here we report crushing extraction and carbon isotope analysis of methane-bearing fluid inclusions in approximately 3.5-Gyr-old hydrothermal precipitates from Pilbara craton, Australia. Our results indicate that the extracted fluids contain microbial methane with carbon isotopic compositions of less than -56 per thousand included within original precipitates. This provides the oldest evidence of methanogen (> 3.46 Gyr ago), pre-dating previous geochemical evidence by about 700 million years.     

小波多尺度方法用于边缘检测

小波极大值有达式给出重构图像信息的一种新方法,它能从图像边缘的属性上扩展解决图像处理问题的方法,由此提出小波多尺度方法对边 进行检测和重构,实验结果表明图像近似值可以从小波模极大值点中重构,而视觉效果却不受影响。     

CD38 is critical for social behaviour by regulating oxytocin secretion

CD38, a transmembrane glycoprotein with ADP-ribosyl cyclase activity, catalyses the formation of Ca2+ signalling molecules, but its role in the neuroendocrine system is unknown. Here we show that adult CD38 knockout (CD38-/-) female and male mice show marked defects in maternal nurturing and social behaviour, respectively, with higher locomotor activity. Consistently, the plasma level of oxytocin (OT), but not vasopressin, was strongly decreased in CD38-/- mice. Replacement of OT by subcutaneous injection or lentiviral-vector-mediated delivery of human CD38 in the hypothalamus rescued social memory and maternal care in CD38-/- mice. Depolarization-induced OT secretion and Ca2+ elevation in oxytocinergic neurohypophysial axon terminals were disrupted in CD38-/- mice; this was mimicked by CD38 metabolite antagonists in CD38+/+ mice. These results reveal that CD38 has a key role in neuropeptide release, thereby critically regulating maternal and social behaviours, and may be an element in neurodevelopmental disorders.     

Treatment of diabetes and atherosclerosis by inhibiting fatty-acid-binding protein aP2

Adipocyte fatty-acid-binding protein, aP2 (FABP4) is expressed in adipocytes and macrophages, and integrates inflammatory and metabolic responses. Studies in aP2-deficient mice have shown that this lipid chaperone has a significant role in several aspects of metabolic syndrome, including type 2 diabetes and atherosclerosis. Here we demonstrate that an orally active small-molecule inhibitor of aP2 is an effective therapeutic agent against severe atherosclerosis and type 2 diabetes in mouse models. In macrophage and adipocyte cell lines with or without aP2, we also show the target specificity of this chemical intervention and its mechanisms of action on metabolic and inflammatory pathways. Our findings demonstrate that targeting aP2 with small-molecule inhibitors is possible and can lead to a new class of powerful therapeutic agents to prevent and treat metabolic diseases such as type 2 diabetes and atherosclerosis.     

基于小波门限化的图像去噪方法

提出用小波门限化方法对图像的噪声进行处理,从理论上分析和探讨了小波门限化的作用,以及对抑制噪声形式的无纹理图像的自适应性,实验结果表明,所处理的图像取得了很大的结果。     

Development of a Mobile Sensing Unit and Its Prototype Implementation

This paper represents a design and development of a mobile sensing unit as well as its prototype implementation for railway track monitoring. The unit consists of an ultra-small personal computer (PC), a global positioning system (GPS) receiver, an accelerometer and an ADC (Analog/Digital Converter) so that the unit can trace the route while capturing an acceleration response of a passenger vehicle. The unit enables more frequent and qualitative data acquisition compared with traditional and the state of the practice railway track inspection equipments. Locating disorder is the key of our unit, which has a reasonable accuracy of positioning with GPS data, existing facilities landmarks, and car acceleration responses. The proposed unit is a promising device for efficient properties management of railway agencies. The prototype implementation shows a result that car acceleration responses are related with the track displacements in low frequencies. The results also imply that sensor settlement on a vehicle floor, not axes or bogies, is effective for capturing track vertical displacements.     

Phosphorylation of Erp1 by p90rsk is required for cytostatic factor arrest in Xenopus laevis eggs

Until fertilization, the meiotic cell cycle of vertebrate eggs is arrested at metaphase of meiosis II by a cytoplasmic activity termed cytostatic factor (CSF), which causes inhibition of the anaphase-promoting complex/cyclosome (APC/C), a ubiquitin ligase that targets mitotic cyclins-regulatory proteins of meiosis and mitosis-for degradation. Recent studies indicate that Erp1/Emi2, an inhibitor protein for the APC/C, has an essential role in establishing and maintaining CSF arrest, but its relationship to Mos, a mitogen-activated protein kinase (MAPK) kinase kinase that also has an essential role in establishing CSF arrest through activation of p90 ribosomal S6 kinase (p90rsk), is unclear. Here we report that in Xenopus eggs Erp1 is a substrate of p90rsk, and that Mos-dependent phosphorylation of Erp1 by p90rsk at Thr 336, Ser 342 and Ser 344 is crucial for both stabilizing Erp1 and establishing CSF arrest in meiosis II oocytes. Semi-quantitative analysis with CSF-arrested egg extracts reveals that the Mos-dependent phosphorylation of Erp1 enhances, but does not generate, the activity of Erp1 that maintains metaphase arrest. Our results also suggest that Erp1 inhibits cyclin B degradation by binding the APC/C at its carboxy-terminal destruction box, and this binding is also enhanced by the Mos-dependent phosphorylation. Thus, Mos and Erp1 collaboratively establish and maintain metaphase II arrest in Xenopus eggs. The link between Mos and Erp1 provides a molecular explanation for the integral mechanism of CSF arrest in unfertilized vertebrate eggs.     

皮纳图博火山喷发对气候影响的数值试验

用俄勒冈州立大学（ＯＳＵ）的两层大气环流模式，研究１９９１年６月中旬菲律宾的皮纳图博（Ｐｉｎａｔｕｂｏ）火山喷发对短期气候的影响．数值试验的结果表明：①火山喷发引起低纬太阳辐射减少，导致次年１，２月模式大气的北半球主要大气活动中心（阿留申低压、冰岛低压、东亚冷高压、北美冷高压等）的强度明显减弱，亚洲和北美大陆中高纬度大部分地区的地面气温明显上升．模拟结果与实况相当一致．皮纳图博火山喷发对北半球中高纬许多地区（如前苏联的西伯利亚的中西部、中国北方地区、日本和西欧以及美国等地）１９９２年１，２月所出现的异常暖冬天气有重要的作用．②火山喷发引起的热带太平洋海平面气压场变化有利于南方涛动的减弱．     

Transient activation of calcineurin is essential to initiate embryonic development in Xenopus laevis

At fertilization, an increase of cytosolic calcium ions (Ca2+) triggers various activation responses in animal eggs. In vertebrates, these responses include exit from metaphase arrest in meiosis II (MII exit) and cortical remodelling initiated by cortical granule exocytosis. Although the essential requirement of Ca2+/calmodulin-dependent protein kinase II for inducing MII exit has been documented, a role of the Ca2+/calmodulin-dependent protein phosphatase calcineurin in egg activation has not been investigated. Here we show, using cell-free extracts from unfertilized eggs of Xenopus laevis, that calcineurin is transiently activated immediately after Ca2+ addition to a concentration that induces MII exit. When calcineurin activation is inhibited, cyclin-dependent kinase 1 (Cdk1) inactivation by means of cyclin B degradation is prevented and sperm chromatin incubated in the extracts remains condensed. Similarly, if calcineurin is inhibited in intact eggs, MII exit on egg activation is prevented. In addition, the activation contraction in the cortex is suppressed whereas cortical granule exocytosis occurs. We further demonstrate that, when a high level of calcineurin activity is maintained after activation, growth of sperm asters is prevented in egg extracts and, consistently, migration of male and female pronuclei towards each other is hindered in fertilized eggs. Thus, both activation and the subsequent inactivation of calcineurin in fertilized eggs are crucial for the commencement of vertebrate embryonic development.