散孔材和环孔材树种叶水分传输能力及其与抗旱性的关系

选取树龄相同的3种散孔材(杨树、梧桐和樱花)和3种环孔材(刺槐、合欢和白蜡)树种,用3种不同方法(解剖法、加压法和水容法)研究了其叶水力导度的差异及与抗旱性(PV曲线参数)的关系.结果显示:解剖法估算的最大叶水力导度高于加压法和水容法,加压法和水容法在6个树种中的5个上测定值完全一致,3种散孔材与环孔材树种的叶最大水力导度无显著差异.3种散孔材树种的饱和渗透势和膨压损失点渗透势与3种环孔材相比差异不大,但膨压损失点的相对含水量则低于环孔材树种,质外体含水量高于环孔材树种,导致其综合抗旱性指数也高于3种环孔材树种.研究表明,散孔材和环孔材树种的叶最大水力导度与其抗旱性之间并无显著相关关系.     

Trichogramma parasitoids for control of Lepidopteran borers in Taiwan: species,life‐history traits and Wolbachia infections

Trichogramma, polyphagous endoparasitoids of lepidopteran eggs, are used against a variety of crop pests throughout the world including those of sugar cane and corn in south‐eastern Asia. Their ability to be easily and economically reared on factitious hosts and their wide host range have contributed to their widespread use in pest control. The overall aim of this study was to select strains for eventual release in crop areas for control of lepidopteran borer pests of sugar cane and corn. To this end, we identified common Trichogramma species emerging from corn borer egg masses throughout south‐western Taiwan, compared their life‐history characteristics, assessed their thermal limits and identified the Wolbachia infection status of collected Trichogramma parasitoids. Trichogramma ostriniae was the most commonly collected species on corn, with occasional detection of T. chilonis and an unidentified species designated as T. sp. y. Although the sex ratio varied widely between sites, Wolbachia infection was detected only at a single site in one species (T. ostriniae). Wolbachia‐infected T. ostriniae were tolerant to high temperature stress. Trichogramma chilonis had lowest fecundity of the three species tested, and a Wolbachia‐infected T. ostriniae strain had lower fecundity than an uninfected strain. Given the limited availability of distribution and historical data for Trichogramma species in Taiwan, the current study provides a baseline for future work and also highlights the importance of accurately identifying species when establishing colonies of natural enemies for biocontrol.     

Construction and characterization of a bacterial artificial chromosome library of thermo-sensitive genie male-sterile rice 5460S

In order to develop a detailed physical map of the thermo-sensitive genie male-sterile (TGMS) gene-encompassing region and finally clone the TGMS gene, a high-quality rice bacterial artificial chromosome (BAC) library from TGMS rice 5460S was constructed. The method of constructing BAC library was examined and optimized. The 5460S library consists of 19 584 BAC clones with an average insert size of 110 kb, which represents about 5 times rice haploid genome equivalents. Rice inserts of up to 140 kb and 250 kb were isolated and appeared stable after 100 generations of serial growth. Hybridization of BAC clones with mitochondrial and chloroplastic genes as probes demonstrated that this library has no organellar contamination. The 5460S library was screened with 3 molecular markers linked to tmsl gene as probes and at least 1 BAC clone was identified with each probe. The insert ends of positive clones were successfully isolated using thermal asymmetric interlaced PCR (TAIL-PCR) technique.     

Expression, purification, and characterization of a structurally disordered and functional C-terminal autoinhibitory domain (AID) of the 70 kDa 40S ribosomal protein S6 kinase-1 (S6K1)

S6K1 is a member of the AGC subfamily of serine-threonine protein kinases, whereby catalytic activation requires dual phosphorylation of critical residues in the conserved T-loop (T229) and hydrophobic motif (HM; T389) peptide regions of its catalytic kinase domain (residues 1-398). In addition to its kinase domain, S6K1 contains a C-terminal autoinhibitory domain (AID; residues 399-502), which prevents T-loop and HM phosphorylation; and autoinhibition is relieved on multi-site Ser-Thr phosphorylation of the AID (S411, S418, T421, and S424). Interestingly, 66 of the 104 C-terminal AID amino acid residues were computer predicted to exist in structurally disordered peptide regions, begetting interest as to how such dynamics could be coupled to autoregulation. To begin addressing this issue, we developed and optimized protocols for efficient AID expression and purification. Consistent with computer predictions, aberrant mobilities in both SDS-PAGE and size-exclusion chromatography, as well as low chemical shift dispersion in (1)H-(15)N HSQC NMR spectra, indicated purified recombinant AID to be largely unfolded. Yet, trans-addition of purified AID effectively inhibited PDK1-catalyzed T-loop phosphorylation of a catalytic kinase domain construct of S6K1. Using an identical purification protocol, similar protein yields of a tetraphospho-mimic mutant AID(D(2)ED) construct were obtained; and this construct displayed only weak inhibition of PDK1-catalyzed T229 phosphorylation. Purification of the structurally 'disordered' and functional C-terminal AID and AID(D(2)ED) constructs will facilitate studies aimed to understand the role of conformational plasticity and protein phosphorylation in modulating autoregulatory domain-domain interactions.     

HIFU治疗下生物体焦域温度分布的研究与应用

高强度聚焦超声(HIFU)为无创治疗肿瘤带来了新的途径,本文对HIFU治疗下生物体焦域热分布和热传导模型的理论进行了初步的介绍,并在理论的指导下进行不同治疗剂量的实验研究,结果表明组织内具有热波传热效应,治疗时可以根据治疗剂量的需要选取不同的参数,以达到最佳治疗效果。     

The thermal biology of three southern African elephant-shrews

1. 1. The thermal characteristics of Petrodromus tetradactylus, Elephantulus intufi and E. brachyrhynchus were investigated and compared with other elephant-shrews that occur in the southern African subregion.

2. 2. E. intufi and E. brachyrhynchus appear to have lower than expected basal metabolic rates (1.1185 ± 0.1623 and 0.9649 ± 0.1638 ml O₂ g⁻¹ h⁻¹, respectively) and high, narrow thermoneutral zones, similar to other elephant-shrews investigated previously. In contrast P. tetradactylus has a basal metabolic rate (0.871 ± 0.027 ml O₂ g⁻¹ h⁻¹) close to expected for body mass, and a broad, low thermoneutral zone.

3. 3. The thermal biology of macroscelids is discussed in terms of their distribution, microhabitat and body size.

     

Modulation of the K(v)4.3 channel by syntaxin 1A

The SNARE protein syntaxin 1A (Syn1A) is known to inhibit delayed rectifier K(+) channels of the K(v)1 and K(v)2 families with heterogeneous effects on their gating properties. In this study, we explored whether Syn1A could directly modulate K(v)4.3, a rapidly inactivating K(v) channel with important roles in neuroendocrine cells and cardiac myocytes. Immunoprecipitation studies in HEK293 cells coexpressing Syn1A and K(v)4.3 revealed a direct interaction with increased trafficking to the plasma membrane without a change in channel synthesis. Paradoxically, Syn1A inhibited K(v)4.3 current density. In particular, Syn1A produced a left-shift in steady-state inactivation of K(v)4.3 without affecting either voltage dependence of activation or gating kinetics, a pattern distinct from other K(v) channels. Combined with our previous reports, our results further verify the notion that the mechanisms involved in Syn1A-K(v) interactions vary significantly between K(v) channels, thus providing a wide scope for Syn1A modulation of exocytosis and membrane excitability.     

基于热扩散方法测定树木蒸腾的潜在误差分析

蒸腾作为植被蒸散的主要分量,是植物水分生理生态学研究的核心内容,其测定方法的研究备受关注.热扩散方法是测量树木蒸腾的最优方法之一.大量研究表明,应用热扩散方法测定的单株树木蒸腾量以及扩展到林分尺度蒸腾耗水量均相对准确,但在测定过程以及测定值与蒸腾真实值之间存在着潜在误差.本文综述了热扩散方法在树干液流通量密度测定以及从温差测定点到单株、从单株到林分尺度扩展过程中存在的潜在误差,展望了我国开展热扩散方法潜在误差分析的主要研究方向,并提出了解决其潜在测量误差的方法.     

我国东南部地区夏季两种雀形目鸟类的代谢产热特征及其体温调节

采用封闭式流体压力呼吸计,分别在5-35℃和5-40℃的环境温度范围内测定了白头鹎(Pycnonotussinensis)和丝光椋鸟(Sturnussericeus)的代谢率、热传导和体温等指标,探讨其代谢产热特征。结果显示:在环境温度(Ta)为5-35℃时,白头鹎的体温基本维持恒定,平均温度为40.3±0.1℃,热中性区为26.6-32.8℃,基础代谢率为73.10±4.11mlO2/h,是体重预期值的79%;Ta在5-26℃范围内,代谢率(MR)与Ta呈负相关,回归方程为:MR[mlO2/h]=265.37-7.24Ta(℃);Ta在5-30℃范围内,热传导值最低且基本保持恒定,平均为0.24±0.01mlO2/g·h·℃,是体重预期值的126%。丝光椋鸟的热中性区为27.6-34.5℃,平均体温为40.5±0.1℃(5-40℃),基础代谢率为160.64±9.20mlO2/h,是体重预期值的90%;最低热传导为0.16±0.05mlO2/g·h·℃,是体重预期值的129%。在5-25℃范围内,MR与Ta的回归方程为:MR[mlO2/h]=377.96-7.88Ta(℃)。白头鹎和丝光椋鸟的基本生物学特征为:较高的体温,热传导和上临界温度,较宽的热中性区和较低的代谢率,符合南方小型鸟类的代谢特征.     

街区尺度屋顶绿化热效应及其与城市形态结构之间的关系

研究探讨大面积屋顶绿化如何改善城市冠层内部三维空间的热环境,改善效果与城市形态结构之间存在的关系。基于三维小气候模型ENVI-met 4.2,开展街区尺度屋顶绿化热效应研究。在南京市选择具有不同形态结构特征的8个典型样区,每个样区设置2种朝向(街道与主导风向平行或相交)、3种屋顶绿化情景(传统光屋顶、简易型绿化、复合型绿化),共对48种情景进行了微气候模拟与分析。结果表明,街区尺度屋顶绿化产生的"冷岛"可从屋面扩散到地面空间,缓解城市冠层热岛效应。白天14:00时,8个样区屋顶1.5 m高处的降温强度最高可达0.64℃,样区平均降温强度最大值为0.44℃;地面1.5 m高处的降温最大值为0.55℃,样区平均降温强度最大值为0.25℃。建筑高度、高宽比、容积率与屋面、地面降温强度之间均存在显著负相关关系;建筑密度与屋面降温强度显著正相关,但与地面降温强度之间无显著相关性。总的来说,紧凑低层建筑区和开敞低层建筑区实施屋顶绿化后产生的降温效应明显高于紧凑和开敞高层建筑区;建筑高度和密度相同时,街道走向与主导风向呈45°夹角比与主导风向平行具有更高的降温强度。研究结果能够促进对亚热带城市地区建筑-植被-大气相互关系的深入认识,并为屋顶绿化实践提供指导。