昼间亚高温下番茄叶中糖含量与蔗糖代谢相关酶的活性日变化

研究番茄品种‘辽园多丽’幼苗在昼间35℃亚高温条件下叶中糖含量及蔗糖代谢相关酶活性日变化的结果表明,昼间亚高温处理后的幼苗叶中果糖、葡萄糖和淀粉含量下降,蔗糖含量升高。与蔗糖代谢相关的酶活性有明显的昼夜节律性变化,转化酶、蔗糖合成酶呈现昼间活性低、夜间活性高的节律性,而蔗糖磷酸合成酶活性在进入夜间时立刻升高。35℃昼间亚高温处理后的幼苗叶中,转化酶活性下降,蔗糖合成酶活性明显升高,蔗糖磷酸合成酶活性则略有升高。     

土壤重金属向节肢动物的传递及影响

土壤中重金属可通过食物链传递至节肢动物,并在其体内累积。文章介绍影响重金属传递和积累的主要因子,及重金属对植食性、捕食性、寄生性、腐食性节肢动物种群及群落的影响情况。建议对影响传递与累积的机制开展深入研究,并重点从节肢动物群落生态学、行为学、生理学等角度开展更多工作。     

粳稻SRAP分子标记遗传群的构建与分析

用超级稻品种‘沈农606’和普通粳稻‘丽江新团黑谷’为亲本杂交获得的102份F_2代单株,通过SRAP分子标记遗传分析,构建了包含14个连锁群,由129个多态性位点组成的水稻连锁图谱,此图谱覆盖基因组长度1671.5 cM,平均图距13.0 cM。连锁群上有17.2%的多态性位点表现偏分离,偏分离标记在连锁群上存在热点区域。     

Degradation of polyethylene succinate (PES) by a new thermophilic <Emphasis Type="Italic">Microbispora</Emphasis> strain

Thermophilic actinomycetes were isolated from sediment of the Chingshuei hot spring in north Taiwan, and the strain HS 45-1 was selected from colonies which formed distinct clear zones on agar plate with emulsified polyethylene succinate (PES). The film of PES disappeared within 6 days in liquid cultures at 50°C. The strain HS 45-1 was also able to degrade poly (ε-carpolactone) (PCL) and poly (3-hydroxybutyrate) (PHB) films completely within 6 days in liquid cultures. Basing on the results of phynotypic characteristics, phylogenetic studies and DNA-DNA hybridization, strain HS 45-1 should be assigned to Micorbispora rosea subsp. taiwanensis.     

Na,K-ATPase alpha2 and Ncx4a regulate zebrafish left-right patterning

A conserved molecular cascade involving Nodal signaling that patterns the laterality of the lateral mesoderm in vertebrates has been extensively studied, but processes involved in the initial break of left-right (LR) symmetry are just beginning to be explored. Here we report that Na,K-ATPase alpha2 and Ncx4a function upstream of Nodal signaling to regulate LR patterning in zebrafish. Knocking down Na,K-ATPase alpha2 and Ncx4a activity in dorsal forerunner cells (DFCs), which are precursors of Kupffer's vesicle (KV), is sufficient to disrupt asymmetric gene expression in the lateral plate mesoderm and randomize the placement of internal organs, indicating that the activity of Na,K-ATPase alpha2 and Ncx4a in DFCs/KV is crucial for LR patterning. High-speed videomicroscopy and bead implantation experiments show that KV cilia are immobile and the directional fluid flow in KV is abolished in Na,K-ATPase alpha2 and Ncx4a morphants, suggesting their essential role in KV ciliary function. Furthermore, we found that intracellular Ca(2+) levels are elevated in Na,K-ATPase alpha2 and Ncx4a morphants and that the defects in ciliary motility, KV fluid flow and placement of internal organs induced by their knockdown could be suppressed by inhibiting the activity of Ca(2+)/calmodulin-dependent protein kinase II. Together, our data demonstrate that Na,K-ATPase alpha2 and Ncx4a regulate LR patterning by modulating intracellular calcium levels in KV and by influencing cilia function, revealing a previously unrecognized role for calcium signaling in LR patterning.     

梭梭(Haloxylon ammodendron)生理与个体用水策略对降水改变的响应

随着全球变化的加剧,降水改变正导致荒漠生态系统中植物用水策略的适应性变化;对降水变化响应的种间差异性影响着荒漠植物群落组成。研究将生理生态与个体形态尺度相结合,调查中亚荒漠关键种梭梭Haloxylon ammodendron对降水变化导致的自然生境中水分条件改变的响应与适应。实验于2005年生长期开展,在古尔班通古特沙漠南缘原始盐生旱生荒漠中设置3个降水梯度（自然、双倍和无降水）;观测并比较不同降水条件下光合作用、蒸腾作用、叶水势、水分利用效率、地上生物量累积和根系分布的变化。结果表明,梭梭主要利用降水形成的浅层土壤水维持生存;有效的形态调节和较强的气孔控制是其维持光合能力以及适应降水变化的主要机制;降水增多对其产生正效应,预示着梭梭可能在未来种间竞争和群落演替中占有优势。     

Conservation of the TRAPPII-specific subunits of a Ypt/Rab exchanger complex

Background  

Ypt/Rab GTPases and their GEF activators regulate intra-cellular trafficking in all eukaryotic cells. In S. cerivisiae, the modular TRAPP complex acts as a GEF for the Golgi gatekeepers: Ypt1 and the functional pair Ypt31/32. While TRAPPI, which acts in early Golgi, is conserved from fungi to animals, not much is known about TRAPPII, which acts in late Golgi and consists of TRAPPI plus three additional subunits.     

利用免疫抑制小鼠模型检测真菌病毒对黄曲霉菌致病力影响

【目的】构建用于比较黄曲霉（Aspergillus flavus,A. flavus）菌株之间致病力差异的小鼠感染模型,并利用该模型评价真菌病毒AfPV1对宿主A. flavus致病力的影响。【方法】用不同浓度环磷酰胺腹腔注射Institute of Cancer Research （ICR）小鼠,根据白细胞的数量判断小鼠免疫抑制程度;通过滴鼻和尾静脉两种感染方法接种不同浓度的A. flavus孢子量,统计14 d以内小鼠的死亡率,确定A. flavus最佳的孢子接种量;通过小鼠组织的菌落负荷量以及肺部组织的病理观察,确定A. flavus感染是否成功;最后利用该小鼠模型评价真菌病毒AfPV1对寄主A. flavus致病力的影响。【结果】腹腔注射环磷酰胺的浓度为250 mg/kg时,能够达到免疫抑制水平;小鼠组织真菌负荷和病理组织切片观察显示A. flavus成功感染接种的ICR小鼠组织;在滴鼻接种模型中,A. flavus的孢子接种量为40μL（1×10⁶CFU/mL）时比较合适评价A. flavus菌株之间的差异;在尾静脉接种的模型中,A. flavus的孢子...     

肽酶PepT参与副溶血弧菌的浮游运动和生物被膜形成

pepT基因编码一种金属依赖性肽酶T (peptidase T,PepT),能特异性催化三肽N端氨基酸,因此也称为氨肽酶T。研究发现大多数氨肽酶参与细菌蛋白质新陈代谢和调节三肽活性,但关于PepT在细菌毒力及致病性方面的报道较少。[目的]本文选取PepT为研究对象,研究其对副溶血弧菌生物学特性及致病性的影响。[方法]通过构建缺失株ΔpepT和回补株CΔpepT,比较菌株在运动性、生物被膜、环境耐受、细胞毒性等方面的差异。[结果]与野生株相比,ΔpepT缺失株的极性鞭毛转录水平极显著下降,浮游运动能力降低;同时生物被膜形成能力减弱,而细菌群集运动及环境耐受能力无显著差异。此外,缺失pepT基因会导致副溶血弧菌的细胞毒性和小鼠毒力作用显著下降。[结论]pepT基因与副溶血弧菌浮游运动和生物被膜形成能力相关,并且影响其致病性。