花粉管细胞结构与生长机制研究进展

花粉管的极性顶端生长是一个复杂的动力学过程,在高等植物有性生殖过程中起着重要的作用。花粉管的生长过程包括许多方面,其中最为重要的是花粉管细胞骨架动态和胞质运动。本文较全面地综述了花粉管的结构、细胞骨架、胞质运动、囊泡转运及循环、线粒体运动以及内质网和高尔基体之间囊泡运动等。     

吸水链霉菌ATCC 29253产Hygrocin A发酵条件的优化

【背景】Hygrocins是一种萘安莎抗生素,具有良好的新药开发潜能。但在常见培养基及发酵条件下菌体内Hygrocin A含量一般很低,甚至难以直接进行准确检测。【目的】提高吸水链霉菌ATCC 29253发酵物中Hygrocin A的产量。【方法】采用单因素与正交试验设计优化相结合的方法系统考察碳源、氮源、磷酸盐、MgCl_2浓度、NaCl浓度、种子菌龄等因素对吸水链霉菌ATCC 29253产Hygrocin A能力的影响。【结果】最佳发酵条件为(g/L):葡萄糖4.0,黄豆饼粉8.0,麦芽提取物10.0,K_2HPO_4 1.5,KH_2PO_4 1.5,NaCl 1.5,Mg Cl2 1.0;种子最佳活化时间为48 h;培养参数:摇床转速200 r/min,初始pH为6.8-7.0,瓶装量50 m L/250 m L,接种量5%,30°C培养10 d。在优化条件下,Hygrocin A产量与其原始培养基M10相比提高了500%,Rapamycin产量同时下降了95%。【结论】通过培养基优化,可显著提高吸水链霉菌ATCC 29253中Hygrocin A产量,为Hygrocin A合成应用研究奠定基础,同时可使Rapamycin产量明显下降。这说明可通过选择培养条件有目的地调节两种抗生素的代谢通量,进而开展多种抗生素同时表达的代谢调控研究。     

Carbon and water fluxes in ecologically vulnerable areas in China

Ecologic vulnerable areas (EVAs) are the regions where ecosystems are fragile and vulnerable to suffer from degradation with external disturbances, e.g. environmental changes and human activities (Feng et al. 2022; Wang et al. 2019). EVAs in China are widely distributed and account for more than 55% China’s land area (Ministry of Ecology and Environment of the People’s Republic of China 2008). The ecosystem in EVAs, chartered with low stability, weak resistance and high vulnerability, has been experiencing significant degradation owing to the impacts of global climate change and human activities (Bai et al. 2018; Chen et al. 2021; Yu et al. 2022). The EVAs in China are not only the most serious areas of environmental degradation, but also the most poverty-stricken regions (Wang et al. 2019). Harsh environmental condition (drought, low temperature and strong radiation) and limited resource supply (water, soil nutrients, etc.) constrain the vegetation productivity and ecosystem services of EVAs (Li et al. 2021). Climate change adds new challenges with warmer temperatures, changing rainfall regime and increasing frequency of extreme events (drought, heat wave, storms, etc.), which make it is more difficult to predict the changes of ecosystem processes and functions in future scenarios (Piao et al. 2020; Reid et al. 2014). Carbon and water fluxes are the core ecosystem processes, which is linked to diverse ecosystem services (Lian et al. 2021). Therefore, clarifying the variations and controls of ecosystem carbon and water fluxes is an effective approach to clarifying how ecosystem respond to global change in EVAs (Baldocchi 2020). As the only technique can directly measure the carbon, water and energy fluxes between vegetation and atmosphere, eddy covariance technique has been considered as a standard method for flux observations (Chen et al. 2020). By integrating long-term, eddy covariance measurements over time and space, researches are able to assess ecosystem metabolism at different time scales (hours to decades) (Forzieri et al. 2020; Han et al. 2020; Jung et al. 2017). Eddy covariance measurements also produce information on how ecosystem respond to the changes in climate, which is useful for assessing ecosystem carbon sequestration (Hu et al. 2018), water and energy balance (Forzieri et al. 2020), resource use efficiency (Liu et al. 2019) and ecosystem feedback to climate change (Huang et al. 2019; Piao et al. 2020; Yue et al. 2020). Long-term flux measurements are also vital for detecting the responses of ecosystem functions to extreme events, optimizing and validating models on regional and global scales (Baldocchi 2020). Combining with remote sensing and ecosystem modeling techniques, scientists can upscale and evaluate the functional relations between carbon and water fluxes with environmental variables at high resolution and across diverse spatial/temporal scales (Niu et al. 2017; Xia et al. 2020).     

长足大竹象消化道不同分段菌群异质性及竹木质纤维素降解能力

[目的]长足大竹象Cyrtotrachelus buqueti消化道共生菌群参与了竹纤维素的降解.本研究旨在揭示长足大竹象幼虫消化道不同分段共生菌群异质性及木质纤维素的降解能力.[方法]通过对16S rRNA测序对长足大竹象幼虫消化道分段口器(YB)、前肠(YFG)、中肠(YMG)和后肠(YHG)进行菌群组成分析及功能...     

海南地区与环渤海湾美人鱼发光杆菌美人鱼亚种水产动物分离株的表型与遗传特征分析

美人鱼发光杆菌美人鱼亚种(Photobacterium damselae subsp.damselae,PDD)是一种广泛分布于海洋环境内的重要病原菌,可导致多种海洋生物患病死亡,近年来在我国不同养殖区域内均有发现和报道.[目的]通过生理代谢表型、毒力基因分布和分子遗传分析,系统比较我国海南地区和环渤海湾不同株系PDD...     

Quantitative determination of helicid in rat biosamples by liquid chromatography electrospray ionization mass spectrometry

A simple liquid chromatography electrospray ionization mass spectrometry (LC–ESI–MS) method with highly improved sensitivities for the determination of helicid in rat bile, urine, feces and most tissues was developed. The tissues and feces were firstly homogenized mechanically using deionized water as the media. Bile, urine, tissues and feces homogenates were extracted by liquid–liquid extraction with n-butyl alcohol for sample preparation. The subsequent analysis procedures were performed on a Shimadzu LCMS2010A system (electrospray ionization single quadrupole mass analyzer). A Luna C₁₈ column (150 mm × 2.00 mm, 5 μm) was used as the analytical column, while a mixture of acetonitrile and ammonium chloride water solution was used as the mobile phase. The proportions of mobile phase were changed timely according to gradient programs. Chlorinated adducts of molecular ions [M+Cl]^? at m/z 319.00 and 363.05 were used to quantify helicid and bergeninum (internal standard), respectively. The method was validated to be accurate, precise and rugged with good linearity. The proposed method was successfully applied to the preclinical tissue distribution and excretion studies of helicid in rats.     

三峡大老岭山地常绿落叶阔叶混交林林隙干扰研究 I．林隙基本特征

为探讨我国亚热带山地常绿落叶阔叶混交林的林隙干扰特征,对三峡大老岭地区这一植被类型进行调查,分析了植被中林隙的数量、类型及成因;林隙形成木（GM）的类型、数量、物种构成和径级结构,以及林隙和GM的多尺度空间格局特征。结果表明1）林隙密度为11.7个*hm-2;冠林隙和扩展林隙分别占森林面积的11.09%和27.06%。平均每个林窗的形成木为4.5株;单株GM形成的林隙只占17.46%,其中翻倒木集群性最强。对林隙形成的贡献大小次序是翻倒木>折干>枯立>折枝。2）林隙成因方面冬雪和春、秋冻雨的影响最大;病害影响其次;树木间的牵连和撞击扩大了林隙的范围;陡峭的地形增大林隙形成的机率;干旱的影响很小。3）68种GM主要是森林建群种;常绿树种形成林隙的平均机率高于落叶种。4）GM的胸径结构表明本地森林林隙干扰十分频繁。     

Study on coastal wetland habitat quality evaluation in Quanzhou Bay, Fujian, China

Coastal wetland is located in the active interface between land and sea, which is one of the richest biodiversity habitats, while it is seriously disturbed and destroyed by anthropogenic activities in both terrestrial and marine parts. Habitat serves as the basis for organism survival, providing food, shelter, water, space and so on, and habitat degradation and loss caused by intense anthropogenic activities is widely considered as the main reason for biodiversity decline and loss. However, there is still limited study on the evaluating methods of coastal wetland habitats, especially for those in a large scale. In this study, methods for evaluating coastal wetland habitat quality, including selecting indicators, setting value assignment criteria and weights were discussed systematically, a method of coastal wetland habitat quality evaluation was established, and the habitat quality in Quanzhou Bay was also evaluated as a case study. The present study provided a new concept and method to assess quantitatively habitat status, indicate the ecological status and its change, and also reflect and predict indirectly the ecological impact of human activities.
Referring to the habitat evaluation system (HES) developed by United States in the mid 1970s, the evaluation method was established by thorough analysis of the characteristics of coastal wetland. The habitat indicators were selected in terms of three habitat factors as follows: chemical factors, including dissolved oxygen (DO), phosphate in seawater, sulfide in sediment, and regional priority pollutants; physical factors, including landscape naturalness index and coastline artificialization index; biological factors, including invasive species risk and area ratio of invasive alien species. Weights were established by Analytic Hierarchy Process, combined with several-round expert evaluation. Evaluation criteria providing principles for value assignment of each indicator, were established referring to previous standards and related researches. The final result for assessing habitat quality was indicated and stated by the value of Habitat Quality Index (HQI), which is the weighted sum of each indicator. Habitat quality increased with the HQI value, with value ranging from 0 to 100.
The established evaluating method was applied to assess the habitat quality of Quanzhou Bay, located in the southeast coastal zone of Fujian Province, with a total area of 136.4 km², which is an important bay in Fujian. Quanzhou Bay wetland is a typical coastal wetland with diverse wetland habitats, including mangrove, estuary, island, aquaculture ponds, salt pan, shallow sea, mud flat and so on. The Quanzhou Bay is now seriously suffering environmental problems, e.g. eutrophication due to great discharge of domestic, agricultural and industrial wastewater, rapid urbanization and reclamation resulting in decreased wetland area, and the invasion of alien species. The evaluation results showed that the habitat quality index value was 68.13, 57.99 and 51.23 in 1989, 2002 and 2008, respectively, indicating that the habitat degraded gradually. The five major factors that led to decline of HQI value were phosphate in seawater, lead in sediment, landscape naturalness index and coastline artificialization index and area ratio of invasive alien species. Therefore, in order to improve and maintain habitat quality, it is urgent to control pollution, large-scale reclamation and Spartina invasion in Quzhou Bay.     

不同培养基对富集筛选脱色真菌菌群的效果比较

利用活性黑RB5和活性红M-3BE作为筛选因子,从染料脱色效果、菌群产酶能力以及菌群中的微生物丰富度三方面比较了酵母培养基A、产漆酶真菌培养基B和白腐真菌培养基D在脱色真菌富集筛选方面的效果。富集筛选结果共得到11组具有明显脱色效果的真菌菌群,其中5组来自于D培养基,A和B培养基各获得3组。来自A培养基的3组菌群显示出最好的脱色效果和最大的菌群丰富度,对50mg/L的活性红M-3BE和酸性红A溶液的脱色率最高达到99.53%和97.42%,从中分离到了16株真菌,初步鉴定分属于水霉科、曲霉科（红曲霉属）、节壶菌科和白粉菌科;而B和D培养基中所获得的菌群脱色效果稍差,从中仅得到3株和2株真菌,初步鉴定属于酵母和青霉。A、B两种培养基在各种染料存在下更易产生木质素过氧化物酶,产漆酶能力较弱,而D培养基产漆酶活性较高。