自然保护区管理效果影响因素

自然保护区的管理效果是保护区管理工作能力的重要考核指标。由于管理基础、管理机制和管理行为的不同,对保护区的管理效果产生影响的因素也有差异。为了剖析保护区管理过程中各项管理要素对管理效果产生影响情况及其重要程度,从林业系统中选取154个国家级自然保护区进行问卷调查,从26项管理要素中得到14项能体现管理有效性的关键评价指标,在此基础上。利用X^2检验的方法,分析这些关键评价指标与保护区的管理效果之间的关系,为今后的管理工作提供参考依据。经过研究,自然保护区管理效果的3个指标（保护状况E1、保护区控制E2、对当地社区经济效益的影响E3）中,目前E1在各个保护区中的管理效果得分中最高,这说明维护保护区的保护状况仍是各个保护区最为重视的工作目标;而保护区管理有效性评价指标中各个因子对于管理效果有不同的影响结果。在这些管理评价指标中,宣传项目是唯一对保护区管理效果中的3个指标都有影响的因素,并对E1这一管理效果因素影响最大,而管理监督评价和旅游管理与收费则是分别对E2、E3的影响最大。通过分析,将会更加明确保护区的管理因素中各个指标的重要性,通过对采取合理的方式,最终可以提高保护区的管理效果。     

草甸棕壤水稻田磷酸酶活性及对施肥措施的响应

1　引　　言土壤有机磷是一种重要的土壤磷素资源 .我国大部分土壤中有机磷占土壤全磷的 2 0 %～ 50 % ,但在森林和草原植被下的土壤可占到 50 %～ 80 % [9].土壤磷酸酶活性直接影响到有机磷库的利用 ,即磷酸酶活性是衡量土壤肥力 ,尤其是土壤有效磷水平的一个重要参考指标[15 ].土壤磷酸酶(Phosphatases)是催化含磷有机酯和酐水解的一类酶的总称 ,其活性高低直接影响着土壤中有机磷的分解转化及其生物有效性 .其中 ,磷酸单酯酶 (酸性、中性、碱性磷酸酶 )活性一直是土壤磷酸酶研究的重点[18].由于土壤中有机磷化合物的复杂性 ,除了磷酸单…     

Electric-field-induced spin switch of endohedral dodecahedrane heterodimers H@C<Subscript>20</Subscript>H<Subscript>n</Subscript>–C<Subscript>20</Subscript>H<Subscript>n</Subscript>@M (M= Cu,Ag and Au,n = 15, 18, and 19): a theoretical study

We designed nine endohedral dodecahedrane heterodimers H@C₂₀H_n-C₂₀H_n@M (M = Cu, Ag, and Au, n = 15, 18, and 19) that may act as single-molecule spin switches, and we predicted theoretically that the ground states of the dimmers shift from low-spin states (S = 0) to the high-spin states (S = 1) under an external electric field applied parallel or perpendicular to the molecular symmetry axes, consisting well with the analyses of Stark effect. Molecular orbitals analyses provide an intuitive insight into the spin crossover behavior. This study expands the application of endohedral chemistry and provides new molecules for designing single-molecule spin switch.     

Identification and characterization of a novel cold-tolerant extracellular protease from Planococcus sp. CGMCC 8088

Extremophiles - A psychrophilic extracellular protease was isolated from the marine bacterium Planococcus sp. M7 found in the deep-sea mud of the Southern Indian Ocean. The mature protease is about...     

The S4-S5 linker acts as a signal integrator for HERG K+ channel activation and deactivation gating

Human ether-à-go-go-related gene (hERG) K(+) channels have unusual gating kinetics. Characterised by slow activation/deactivation but rapid inactivation/recovery from inactivation, the unique gating kinetics underlie the central role hERG channels play in cardiac repolarisation. The slow activation and deactivation kinetics are regulated in part by the S4-S5 linker, which couples movement of the voltage sensor domain to opening of the activation gate at the distal end of the inner helix of the pore domain. It has also been suggested that cytosolic domains may interact with the S4-S5 linker to regulate activation and deactivation kinetics. Here, we show that the solution structure of a peptide corresponding to the S4-S5 linker of hERG contains an amphipathic helix. The effects of mutations at the majority of residues in the S4-S5 linker of hERG were consistent with the previously identified role in coupling voltage sensor movement to the activation gate. However, mutations to Ser543, Tyr545, Gly546 and Ala548 had more complex phenotypes indicating that these residues are involved in additional interactions. We propose a model in which the S4-S5 linker, in addition to coupling VSD movement to the activation gate, also contributes to interactions that stabilise the closed state and a separate set of interactions that stabilise the open state. The S4-S5 linker therefore acts as a signal integrator and plays a crucial role in the slow deactivation kinetics of the channel.     

ATL3 Is a Tubular ER-Phagy Receptor for GABARAP-Mediated Selective Autophagy

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枯草芽孢杆菌中一种新型双向启动子的功能鉴定

本研究旨在通过转录组分析预测的方法,由地衣芽孢杆菌中筛选获得一种新型双向启动子,鉴定其启动强度。以已知强组成型启动子pShuttle-09为对照,检测其对克劳氏芽孢杆菌碱性蛋白酶基因的表达活性。成功构建了3种重组碱性蛋白酶表达载体及对应的工程菌株。在新型启动子pLA和其反向启动子pLB调控转录下,克劳氏芽孢杆菌碱性蛋白酶表达活性达到164 U/mL和111 U/mL。结果表明,pLA的启动强度明显高于pShuttle-09和pLB,pLA启动子与pLB启动子均可表达碱性蛋白酶。从而为枯草芽孢杆菌表达系统中异源基因的表达提供一个新的方向,也为原核生物中共同表达两种基因提供了新的思路。     

Chemical Constituents from a Mangrove-Derived Actinobacteria Isoptericola chiayiensis BCRC 16888 and Evaluation of Their Anti-NO Activity

Cultivation of the actinobacteria strain Isoptericola chiayiensis, a mangrove - derived actinobacteria that was isolated from a mangrove soil collected in Chiayi County, resulted in the isolation of one new 2-furanone derivative, isopterfuranone ( 1 ), one new sesquiterpenoid, isopterchiayione ( 2 ), one new benzenoid derivative, isopterinoid ( 3 ), five new flavonoids, chiayiflavans A−E ( 4 – 8 ), and 4 metabolites isolated for the first time from nature source, methyl 3-(4-methyl-2,5-dioxopyrrolidin-3-yl)propanoate ( 9 ), 3-ethyl-4-methylpyrrolidine-2,5-dione ( 10 ), chiayiensol ( 11 ) and chiayiensic acid ( 12 ). Their structures were determined through in-depth spectroscopic and mass-spectrometric analyses. Most of the isolates showed potent inhibitory effects on NO production in LPS-stimulated RAW 264.7 murine macrophages cells with IC₅₀ values ranging from 9.36 to 40.02 μM. Of these isolates, 4 and 5 showed NO inhibitory activity with IC₅₀ values of 17.14 and 9.36 μM, stronger than the positive control quercetin (IC₅₀=36.95 μM). This is the first report on flavan metabolites from the genus Isoptericola.     

南北样带温带区栎属树种种子化学组成与气候因子的关系

选取南北样带温带区8个核心分布区的7种优势栎属树种作为对象,通过检测种子的化学组成,包括淀粉、蛋白质、油脂、可溶性总糖、单宁和脯氨酸,分析其化学组成与气候因子之间的关系,结果发现:在气候因子中,温度是影响种子化学组成的主要因素,日照时数次之,而降水没有明显影响.在南北样带温带区,随纬度的增加,温度降低,年日照时数增加,生长积温减少,生长季缩短,淀粉含量积累下降,并趋向于水解为可溶性糖类;同时,从南到北,为适应低温的环境条件,栎属树种通过增加种子蛋白质、可溶性总糖和脯氨酸的含量,以提高种子的抗寒性.栎属树种种子的化学组成之间存在一定的相互关系,可溶性总糖、蛋白质和脯氨酸之间呈正相关关系,它们三者与淀粉均为负相关,种子化学组成之间的这种相互关系是植物对环境适应的生态策略.     

Crystal structure of a procaspase-7 zymogen: mechanisms of activation and substrate binding.

Apoptosis is primarily executed by active caspases, which are derived from the inactive procaspase zymogens through proteolytic cleavage. Here we report the crystal structures of a caspase zymogen, procaspase-7, and an active caspase-7 without any bound inhibitors. Compared to the inhibitor-bound caspase-7, procaspase-7 zymogen exhibits significant structural differences surrounding the catalytic cleft, which precludes the formation of a productive conformation. Proteolytic cleavage between the large and small subunits allows rearrangement of essential loops in the active site, priming active caspase-7 for inhibitor/substrate binding. Strikingly, binding by inhibitors causes a 180 degrees flipping of the N terminus in the small subunit, which interacts with and stabilizes the catalytic cleft. These analyses reveal the structural mechanisms of caspase activation and demonstrate that the inhibitor/substrate binding is a process of induced fit.