环氧树脂固定化的Bacillus sp.DL-2胞外蛋白酶在拆分(±)-乙酸苏合香酯中的应用

环氧基是一个非常活跃的基团,它能与酶、蛋白质和核酸等生物分子发生反应形成共价键,有利于生物分子的固定化。经共价结合法固定化的酶其稳定性及重复使用性可得到显著提高。用环氧树脂ES-103B为载体采用共价结合法对海洋细菌Bacillus sp. DL-2的胞外蛋白酶进行固定化,经过单因素实验优化条件得出最优固定化条件为:p H 8. 0的胞外蛋白酶溶液,25 g/L的ES-103B,45℃下反应8h。采用此最优条件下的固定化酶拆分(±)-乙酸苏合香酯制备出了e. e. p=97. 5%的(R)-1-苯乙醇(产率为45. 0%)和e. e. s=99. 2%的(S)-乙酸苏合香酯(产率为83. 9%)。该固定化酶拆分(±)-乙酸苏合香酯在重复使用8次后制备出的(R)-1-苯乙醇的e. e. p仍大于90%,且固定化胞外蛋白酶在4℃下具有较好的储存稳定性。     

20世纪90年代以来中国生态空间演化的时空格局和梯度效应

改革开放以来中国经济和城市化的快速发展促使生产和生活空间挤占大量生态空间，系统认识和评估我国生态空间演化的宏观格局和过程对于生态文明建设具有重要的理论和现实意义。为揭示全国生态空间变化的时空过程，在对生态空间内涵进行界定的基础上，结合全国尺度时序土地利用数据构建生态空间分类体系，并评估1990-2015年中国生态空间演化特征。结果表明：1990-2015年中国生态用地面积持续减少，主要向半生态用地转变，发生在重要的粮食生产区域及周边；半生态用地面积波动明显，前期主要表现为不断扩张，后期大量转换为弱生态用地，发生在主要城市群地区；弱生态用地持续扩张，与城镇化进程不断加速相关。中国生态空间演变过程表现出一定的区域差异和梯度效应，不同区域生态空间变化发生的拐点时间有所不同，呈现"自东向西、由南到北"的3级梯度特征，区域生态空间状况与经济发展战略及生态空间管控具有较强的相关性。本研究对于国家生态空间管控近远期战略方案制订具有一定启示，建议处于不同梯度的各地区应基于区域生态空间演化所处阶段和不同驱动机制，确定分区域生态空间安全红线目标和生态空间管控方案。     

Combined Strategy of Endothelial Cells Coating,Sertoli Cells Coculture and Infusion Improves Vascularization and Rejection Protection of Islet Graft

Improving islet graft revascularization and inhibiting rejection become crucial tasks for prolonging islet graft survival. Endothelial cells (ECs) are the basis of islet vascularization and Sertoli cells (SCs) have the talent to provide nutritional support and exert immunosuppressive effects. We construct a combined strategy of ECs coating in the presence of nutritious and immune factors supplied by SCs in a co-culture system to investigate the effect of vascularization and rejection inhibition for islet graft. In vivo, the combined strategy improved the survival and vascularization as well as inhibited lymphocytes and inflammatory cytokines. In vitro, we found the combinatorial strategy improved the function of islets and the effect of ECs-coating on islets. Combined strategy treated islets revealed higher levels of anti-apoptotic signal molecules (Bcl-2 and HSP-32), survival and function related molecules (PDX-1, Ki-67, ERK1/2 and Akt ) and demonstrated increased vascular endothelial growth factor receptor 2 (KDR) and angiogenesis signal molecules (FAk and PLC-γ). SCs effectively inhibited the activation of lymphocyte stimulated by islets and ECs. Predominantly immunosuppressive cytokines could be detected in culture supernatants of the SCs coculture group. These results suggest that ECs-coating and Sertoli cells co-culture or infusion synergistically enhance islet survival and function after transplantation.     

Phylogeny of Stephanidae (Hymenoptera: Apocrita) with a new genus from Upper Cretaceous Myanmar amber

A new wasp species, Lagenostephanus lii Li, Rasnitsyn, Shih and Ren gen. et sp.n. , is assigned to Stephaninae (Hymenoptera: Stephanidae). The specimen is described from the lowermost Upper Cretaceous Myanmar (Burmese) amber. This is the second stephanid wasp described from Myanmar amber after Kronostephanus zigrasi Engel & Grimaldi, representing the earliest fossil occurrences of Stephanidae. Based on morphological characters of all extant and extinct genera, a phylogenetic analysis of Stephanidae was conducted. The results indicate that Schlettereriinae and Stephaninae are monophyletic, whereas Electrostephanus Brues, as the only genus within Electrostephaninae, belongs to Stephaninae. Therefore, we propose a synonymy of Electrostephaninae with Stephaninae. Based on the fossil evidence, we infer that the family of Stephanidae was significantly diverse in the Late Cretaceous and that they originated during the Early Cretaceous or late Jurassic. A key to genera of Stephanidae is provided. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:C082C245-8FD3-42B0-880F-94333286500B .     

A 3-hydroxy-3-methylglutaryl-CoA synthase-based probe for the discovery of the acyltransferase-less type I polyketide synthases

Acyltransferase (AT)-less type I polyketide synthases (PKSs) produce complex natural products due to the presence of many unique tailoring enzymes. The 3-hydroxy-3-methylglutaryl coenzyme A synthases (HCSs) are responsible for β-alkylation of the growing polyketide intermediates in AT-less type I PKSs. In this study, we discovered a large group of HCSs, closely associated with the characterized and orphan AT-less type I PKSs through in silico genome mining, sequence and genome neighbourhood network analyses. Using HCS-based probes, the survey of 1207 in-house strains and 18 soil samples from different geographic locations revealed the vast diversity of HCS-containing AT-less type I PKSs. The presence of HCSs in many AT-less type I PKSs suggests their co-evolutionary relationship. This study provides a new probe to study the abundance and diversity of AT-less type I PKSs in the environment and microbial strain collections. Our study should inspire future efforts to discover new polyketide natural products from AT-less type I PKSs.     

Guyiling jianboni gen. et sp.n., an antlion‐like lacewing,illuminating homologies and transformations in Neuroptera wing venation

A new genus and species of antlion‐like fossil lacewing, Guyiling jianboni gen. et sp.n. (Insecta: Neuroptera) are described based on a single specimen from the Yixian Formation (Liaoning Province, China; Early Cretaceous). The new taxon exhibits derived traits such as distally dilated antennae and well‐developed anterior Banksian line (known in Myrmeleontidae), but also genuine plesiomorphies (at the level of Myrmeleontiformia), such as the divergence of a distinct CuA1 stem from MP2 + CuA1 (forewing), and a basal origin of MA (diverging from RP + MA; both wing pairs). This combination is unique among the ‘Palaeoleontidae’, a group better considered as a paraphyletic assemblage of various stem‐Myrmeleontiformia. The wing morphology of the new species is considered in the light of a survey of wing venation topological homologies (and implied transformations) among several Neuroptera families. The survey includes a revision of the holotype of Leptolingia jurassica Ren (Grammolingiidae; Jiulongshan Formation, Daohugou locality, Inner Mongolia Autonomous Region, China; middle Jurassic). The forewing morphology of Guyiling jianboni gen. et sp.n. demonstrates that the fusion of MP2 with CuA, and the differentiation of CuA into two distinct main stems (namely CuA1 and CuA2) are traits shared with Myrmeleontidae and Ascalaphidae (and possibly Nemopteridae). However, the survey also demonstrates that a fusion of MP2 with CuA occurred repeatedly among Neuropterida, although by means of various modalities (namely translocation vs regular fusion). The ‘pectinate fusion’ of CuA(1) with MP2 [i.e. CuA1 has no distinct stem and emits successive branches from MP2 + CuA(1) partim] is a further step in this fusion, and occurred repeatedly as well (at least in the hind wings of Osmylidae and Nymphidae, and both fore‐ and hindwings of a sub‐group of Myrmeleontiformia including Myrmeleontidae and Ascalaphidae, and possibly Nemopteridae). It is anticipated that the current contribution will constitute useful background information for further studies, focusing on particular transformation cases, ideally including a documentation of intraspecific variation.