Heterochronic shifts during early cranial neural crest cell migration in two ranid frogs

We describe the development of the cranial neural crest cell streams relative to embryonic events such as neural tube formation and somite appearance in two Eurasian frog species belonging to the Ranidae, Rana temporaria and Sylvirana nigrovittata, and demonstrate developmental heterochronies. The mandibular stream appeared well developed in R. temporaria at a time when the embryo was still spherical, the neural folds were elevated, and the neural plate was wide open, thus earlier than known from any frog species so far. The appearance of the second stream and its division into hyoid and branchial portions was clearly accelerated in R. temporaria relative to other embryonic events when compared to S. nigrovittata. For example, in R. temporaria, the hyoid and branchial portions of the cranial neural crest cell streams were separated before the neural folds had started to fuse, whereas in S. nigrovittata this event took place only after the neural folds had fused completely. Such ostentatious heterochronies related to the characters used herein have formerly only been reported from comparisons between species belonging to different higher taxa. Our results re‐confirm that to understand the full dynamics of the evolution of development, studies need to implement comparative embryological approaches, and include phylogenetically relatively closely related taxa.     

蜜蜂——新兴的模式生物

蜜蜂作为具有重要经济价值和生态价值的社会性昆虫, 在诸如神经生物学和社会生物学等研究领域也具有很高的模型价值。蜜蜂基因组工程为深入认识蜜蜂的生物学特点,进一步发挥其在多个研究领域的模型价值奠定了分子基础。本文基于蜜蜂的生物学特点,介绍了蜜蜂作为模式生物所具备的优势,及其在学习和记忆、劳动分工、级型分化、免疫等热点领域的研究价值。通过总结和展望国内外蜜蜂生物学研究形势,呼吁国内相关各学科开展合作研究。     

Thioredoxins, glutaredoxins, and glutathionylation: new crosstalks to explore

Oxidants are widely considered as toxic molecules that cells have to scavenge and detoxify efficiently and continuously. However, emerging evidence suggests that these oxidants can play an important role in redox signaling, mainly through a set of reversible post-translational modifications of thiol residues on proteins. The most studied redox system in photosynthetic organisms is the thioredoxin (TRX) system, involved in the regulation of a growing number of target proteins via thiol/disulfide exchanges. In addition, recent studies suggest that glutaredoxins (GRX) could also play an important role in redox signaling especially by regulating protein glutathionylation, a post-translational modification whose importance begins to be recognized in mammals while much less is known in photosynthetic organisms. This review focuses on oxidants and redox signaling with particular emphasis on recent developments in the study of functions, regulation mechanisms and targets of TRX, GRX and glutathionylation. This review will also present the complex emerging interplay between these three components of redox-signaling networks.Electronic Supplementary Material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

海洋生物活性物质与害虫防治

由于有机合成杀虫剂的生态毒性影响和害虫抗药性的发展,目前世界范围的注意力集中于可生物降解和对环境友好的天然害虫控制剂的研究应用上.海洋是生物活性物质的巨大宝库,也是开发害虫控制剂的新来源.本文综述了海洋生物资源、海洋杀虫活性物质的主要类型及海洋活性物质生物筛选技术的发展方向,并简述了海洋源杀虫剂的应用发展前景.     

Genetically modified potatoes expressing Cry 3A protein do not affect aphidophagous coccinellids

Abstract:  Field investigations showed that genetically modified Bacillus thuringiensis (Bt) potato plants ('New Leaf' expressing Cry 3Aa toxic protein) were not damaged by the Colorado potato beetle (CPB) Leptinotarsa decemlineata and contained diverse populations of the aphidophagous coccinellids Coccinella septempunctata , Coccinula quatuordecimpustulata , Hippodamia variegata and Propylea quatuordecimpunctata . The insecticides, alpha-cypermethrin and fipronil, were used for control of CPB in the fields with the non-transgenic standard potatoes 'Santana' and 'Arinda'. Both insecticides caused significant decrease in the abundance of aphidophagous coccinellids. Laboratory experiments revealed that Bt potatoes expressing Cry 3Aa had no effect on the aphid Myzus persicae and that the aphids fed on Bt potatoes had no effect on the larval development and mortality of C. septempunctata .     

6种陆生植物提取物对白脊藤壶无节幼体的毒杀活性比较

对夹竹桃科（Apocynaceae）的红花夹竹桃（Nerium indicum Mill．）和黄花夹竹桃（Thevetia peruviana K．Schum．）、百合科（Li｜iaceae）的洋葱（Allium cepa L．）和大蒜（A．sativum L．）、楝科（Meliaceae）的苦楝（Melia azedarach L．）和印楝（Azadirachta indica A．Juss．）等6种陆生植物的不同溶剂提取物对白脊藤壶（Balanus albicostatus Pilsbry）无节幼体的毒杀作用进行了比较研究。结果表明,供试的楝科和夹竹桃科的4种植物提取物对白脊藤壶无节幼体的毒杀活性高于洋葱和大蒜;不同提取物的毒杀活性与植物的种类及提取部位（叶、花）以及活性成分的类型有关,用非极性有机溶剂提取的脂溶性提取物的毒杀活性高于极性溶剂提取物。处理12h,0．3％印楝素乳油的乙酸乙酯及95％乙醇稀释液的毒杀活性最高,LC50仅为0．33和3．01g·mL^-1,可作为防治海洋污损生物的植物资源进行进一步的开发利用。     

HIV-1 Vpr-induced cell death in Schizosaccharomyces pombe is reminiscent of apoptosis

Human immunodeficiency virus type 1 （HIV-1） Vpr induces cell death in mammalian and fssion yeast cells, suggesting that Vpr may affect a conserved cellular process. It is unclear, however, whether Vpr-induced yeast cell death mimics Vpr-mediated apoptosis in mammalian cells. We have recently identified a number of Vpr suppressors that not only suppress Vpr-induced cell death in fission yeast, but also block Vpr-induced apoptosis in mammalian cells. These findings suggest that Vpr-induced cell death in yeast may resemble some of the apoptotic processes of mammalian cells. The goal of this study was to develop and validate a fission yeast model system for future studies of apoptosis. Similar to Vpr-induced apoptosis in mammalian cells, we show here that Vpr in fission yeast promotes phosphatidylserine externalization and induces hyperpolarization of mitochondria, leading to changes of mitochondrial membrane potential. Moreover, Vpr triggers production of reactive oxygen species （ROS）, indicating that the apoptotic-like cell death might be mediated by ROS. Interestingly, Vpr induces unique morphologic changes in mitochondria that may provide a simple marker for measuring the apoptotic-like process in fission yeast. To verify this possibility, we tested two Vpr suppressors （EF2 and Hspl6） that suppress Vpr-induced apoptosis in mammalian cells in addition to a newly identified Vpr suppressor （Skpl）. All three proteins abolished cell death mediated by Vpr and restored normal mitochondrial morphology in the yeast cells. In conclusion, Vpr-induced cell death in fission yeast resembles the mammalian apoptotic process. Fission yeast may thus potentially be used as a simple model organism for the future study of the apoptotic-like process induced by Vpr and other proapoptotic agents.     

Event-specific qualitative and quantitative PCR methods for the detection of genetically modified rapeseed Oxy-235

Oxy-235 is an oxynil-tolerant genetically modified rapeseed approved for commercialized planting in Canada. The aim of this study was to establish event-specific qualitative and quantitative detection methods for Oxy-235. Both the 5'- and 3'-junction sequences spanning the plant DNA and the integrated gene construct of the Oxy-235 event were isolated, sequenced and analyzed. A 1298-bp deletion of the rapeseed genomic DNA that showed a high similarity to the mRNA sequence of Arabidopsis thaliana was found in the integration site of the insert DNA. Event-specific qualitative PCR methods were established, with one method producing a 105-bp product specific for the 5'-integration junction and the other method producing a 124-bp product specific for the 3'-junction. The absolute detection limits for the qualitative PCR were determined to be 100 initial template copies for the 5'-junction and ten for the 3'-junction. Quantitative methods were also developed that targeted both of the junction fragments. The limit of detection of the quantitative PCR analysis was ten initial template copies for either the 5'- or 3'-junction, while the limit of quantification was determined to be approximately 50 initial template copies. The real-time PCR systems so established were examined with two mixed rapeseed samples with known Oxy-235 contents and found to obtain the expected results.     

Does high relatedness promote cheater‐free multicellularity in synthetic lifecycles?

The evolution of multicellularity is one of the key transitions in evolution and requires extreme levels of cooperation between cells. However, even when cells are genetically identical, noncooperative cheating mutants can arise that cause a breakdown in cooperation. How then, do multicellular organisms maintain cooperation between cells? A number of mechanisms that increase relatedness amongst cooperative cells have been implicated in the maintenance of cooperative multicellularity including single‐cell bottlenecks and kin recognition. In this study, we explore how relatively simple biological processes such as growth and dispersal can act to increase relatedness and promote multicellular cooperation. Using experimental populations of pseudo‐organisms, we found that manipulating growth and dispersal of clones of a social amoeba to create high levels of relatedness was sufficient to prevent the spread of cheating mutants. By contrast, cheaters were able to spread under low‐relatedness conditions. Most surprisingly, we saw the largest increase in cheating mutants under an experimental treatment that should create intermediate levels of relatedness. This is because one of the factors raising relatedness, structured growth, also causes high vulnerability to growth rate cheaters.