Zn对细胞保护作用机理的研究

应用扫描质子微探针和同步辐射ｘ荧光分析技术测定了细胞中元素的分布和组成,为确定Zn是细胞结构成分提供了直接的实验依据.用上述核技术结合有关生化指标,分析测定了正常和损伤细胞（脂质过氧化损伤）中Fe,Zn和丙二醛、SH基含量变化的相互关系.实验结果表明,当细胞发生脂质过氧化损伤时,Fe含量和丙二醛含量同步增高,而Zn含量和SH基量则降低.给细胞补充Zn后,提高了细胞质膜中的Zn含量,SH基量也随之增加,同时丙二醛量降低.提示Zn保护细胞完整性的作用机理之一是控制脂质过氧化作用.Zn可保护膜蛋白的SH基,减少和阻止被Fe所催化的过氧化反应.     

Control of gluconeogenic growth by pps and pck in Escherichia coli.

It is well-known that Escherichia coli grows more slowly on gluconeogenic carbon sources than on glucose. This phenomenon has been attributed to either energy or monomer limitation. To investigate this problem further, we varied the expression levels of pck, encoding phosphoenolpyruvate carboxykinase (Pck), and pps, encoding phosphoenolpyruvate synthase (Pps). We found that the growth rates of E. coli in minimal medium supplemented with succinate and with pyruvate are limited by the levels of Pck and Pps, respectively. Optimal overexpression of pck or pps increases the unrestricted growth rates on succinate and on pyruvate, respectively, to the same level attained by the wild-type growth rate on glycerol. Since Pps is needed to supply precursors for biosyntheses, we conclude that E. coli growing on pyruvate is limited by monomer supply. However, because pck is required both for biosyntheses and catabolism for cells growing on succinate, it is possible that growth on succinate is limited by both monomer and energy supplies. The growth yield with respect to oxygen remains approximately constant, even though the overproduction of these enzymes enhances gluconeogenic growth. It appears that the constant yield for oxygen is characteristic of efficient growth on a particular substrate and that the yield is already optimal for wild-type strains. Further increases in either Pck or Pps above the optimal levels become growth inhibitory, and the growth yield for oxygen is reduced, indicating less efficient growth.     

Enhancing the structural diversity between forest patches—A concept and real-world experiment to study biodiversity,multifunctionality and forest resilience across spatial scales

Intensification of land use by humans has led to a homogenization of landscapes and decreasing resilience of ecosystems globally due to a loss of biodiversity, including the majority of forests. Biodiversity–ecosystem functioning (BEF) research has provided compelling evidence for a positive effect of biodiversity on ecosystem functions and services at the local (α-diversity) scale, but we largely lack empirical evidence on how the loss of between-patch β-diversity affects biodiversity and multifunctionality at the landscape scale (γ-diversity). Here, we present a novel concept and experimental framework for elucidating BEF patterns at α-, β-, and γ-scales in real landscapes at a forest management-relevant scale. We examine this framework using 22 temperate broadleaf production forests, dominated by Fagus sylvatica. In 11 of these forests, we manipulated the structure between forest patches by increasing variation in canopy cover and deadwood. We hypothesized that an increase in landscape heterogeneity would enhance the β-diversity of different trophic levels, as well as the β-functionality of various ecosystem functions. We will develop a new statistical framework for BEF studies extending across scales and incorporating biodiversity measures from taxonomic to functional to phylogenetic diversity using Hill numbers. We will further expand the Hill number concept to multifunctionality allowing the decomposition of γ-multifunctionality into α- and β-components. Combining this analytic framework with our experimental data will allow us to test how an increase in between patch heterogeneity affects biodiversity and multifunctionality across spatial scales and trophic levels to help inform and improve forest resilience under climate change. Such an integrative concept for biodiversity and functionality, including spatial scales and multiple aspects of diversity and multifunctionality as well as physical and environmental structure in forests, will go far beyond the current widely applied approach in forestry to increase resilience of future forests through the manipulation of tree species composition.     

青春型双歧杆菌生态制品对小鼠肝癌抑制作用的初步研究

本文观察了青春型双歧杆菌(Bif.a)对小鼠肝癌移植瘤的抑制作用。结果发现,青春型双歧杆菌在瘤细胞移植前或移植后应用均显示了抑制肿瘤生长的作用。将青春型双歧杆菌注入肤腔可激活肤腔巨噬细胞,提高其吞噬功能和非特异性酯酶活性,而加入体外培养的小鼠肝癌细胞未显示有杀伤瘤细胞作用。认为青春型双歧杆菌的抑瘤作用可能是该菌刺激了宿主的免疫活性细胞杀伤了瘤细胞,而非直接杀伤作用。     

中华蜜蜂和意大利蜜蜂感染囊状幼虫病毒后免疫及发育相关基因表达比较

【目的】本文旨在探究囊状幼虫病毒(sacbrood virus, SBV)对中华蜜蜂(Apis cerana cerana,简称中蜂)和意大利蜜蜂(Apis mellifera ligustica,简称意蜂)工蜂幼虫发育和免疫基因、营养代谢基因、抗病毒基因、细胞发育及代谢相关基因表达的影响。【方法】从蜂群中移取2日龄的中蜂和意蜂幼虫,在培养箱(34℃, RH 85%)进行人工饲养,3日龄时接种SBV病毒,每天观察记录死亡情况,并通过实时定量PCR (real-time quantitative polymerase chain reaction, RT-qPCR)检测4日龄和7日龄幼虫体内SBV基因相对表达量,及免疫基因(Apidaecin、Abaecin、Hymenoptaecin、Denfensin、Lys-1、Pgrp-lc、Kenny、Domeless)、营养代谢基因(Ilp1、Hex110、Vg)、抗病毒基因(Dis3、Dicer、Ago1)、细胞组成及发育调控基因(Vhdl、Co-1-iv)以及细胞代谢和调控基因(Mta1)的表达水平。【结果】通过分析比较发现,感染相同剂量...     

Diverse flowering responses subjecting to ambient high temperature in soybean under short-day conditions

Flowering time is one of important agronomic traits determining the crop yield and affected by high temperature. When facing high ambient temperature, plants often initiate early flowering as an adaptive strategy to escape the stress and ensure successful reproduction. However, here we find opposing ways in the short-day crop soybean to respond to different levels of high temperatures, in which flowering accelerates when temperature changes from 25 to 30 °C, but delays when temperature reaches 35 °C under short day. phyA-E1, possibly photoperiodic pathway, is crucial for 35 °C-mediated late flowering, however, does not contribute to promoting flowering at 30 °C. 30 °C-induced up-regulation of FT2a and FT5a leads to early flowering, independent of E1. Therefore, distinct responsive mechanisms are adopted by soybean when facing different levels of high temperatures for successful flowering and reproduction.     

Ribosomal protein L22-like1 promotes prostate cancer progression by activating PI3K/Akt/mTOR signalling pathway

Prostate cancer (PCa) is one of the most common malignancies in men. Ribosomal protein L22-like1 (RPL22L1), a component of the ribosomal 60 S subunit, is associated with cancer progression, but the role and potential mechanism of RPL22L1 in PCa remain unclear. The aim of this study was to investigate the role of RPL22L1 in PCa progression and the mechanisms involved. Bioinformatics and immunohistochemistry analysis showed that the expression of RPL22L1 was significantly higher in PCa tissues than in normal prostate tissues. The cell function analysis revealed that RPL22L1 significantly promoted the proliferation, migration and invasion of PCa cells. The data of xenograft tumour assay suggested that the low expression of RPL22L1 inhibited the growth and invasion of PCa cells in vivo. Mechanistically, the results of Western blot proved that RPL22L1 activated PI3K/Akt/mTOR pathway in PCa cells. Additionally, LY294002, an inhibitor of PI3K/Akt pathway, was used to block this pathway. The results showed that LY294002 remarkably abrogated the oncogenic effect of RPL22L1 on PCa cell proliferation and invasion. Taken together, our study demonstrated that RPL22L1 is a key gene in PCa progression and promotes PCa cell proliferation and invasion via PI3K/Akt/mTOR pathway, thus potentially providing a new target for PCa therapy.     

不同气候区绿色屋顶蒸散发模拟研究

蒸散发过程决定绿色屋顶雨水滞留能力的恢复,进而影响绿色屋顶径流调控功能。基于水量平衡原理和Penman-Monteith公式,利用北京市实验绿色屋顶气象和蒸散发连续监测数据,构建并验证绿色屋顶水文过程模型,模拟分析不同气候区城市绿色屋顶蒸散发变化规律。结果表明：(1)该模型能较准确模拟绿色屋顶蒸散发量,率定和检验期的Nash-Sutcliffe效率系数分别为0.6385和0.6014,决定系数(R²)分别为0.7191和0.6168;(2)基质厚度相同的情况下,从半干旱区(兰州)、半湿润区(北京)到湿润区(武汉和广州),绿色屋顶日平均实际蒸散发量呈增加趋势;(3)增加基质厚度可提升绿色屋顶最大雨水滞留能力,进而增加绿色屋顶实际蒸散发量,但基质厚度对绿色屋顶蒸散发量的影响存在阈值,在兰州、北京、武汉和广州,当基质厚度分别超过10 cm、17 cm、24 cm和25 cm时,绿色屋顶的日平均实际蒸散发量变化不再明显。此外,不同气候区城市绿色屋顶的日平均实际蒸散发量也存在阈值,广州绿色屋顶日平均实际蒸散发量的阈值依次高于武汉、北京和兰州。本研究有望为我国不同气候区绿色屋...     

国家公园农户对野生动物肇事保险购买意愿及其影响因素——以大熊猫国家公园为例

国家公园内人与野生动物冲突严重,建立野生动物肇事保险机制是减缓冲突的重要举措。以大熊猫国家公园周边社区为例,分析建立国家公园以及农户风险偏好对野生动物肇事保险购买意愿的影响,并探讨冲突程度和制度信任的中介效应。研究结果表明建立国家公园显著增加了农户野生动物肇事保险购买意愿,而农户风险偏好对保险购买意愿会产生负向显著影响。冲突程度和制度信任是重要的中介变量,冲突程度和制度信任均对农户保险购买意愿产生正向显著影响。建立国家公园显著增加了人与野生动物冲突严重程度,进而对保险购买意愿产生正向影响。此外,建立国家公园显著降低了农户制度信任,进而对保险购买意愿产生负向影响。农户风险偏好对野生动物肇事损失程度产生正向显著影响,进而对保险购买意愿产生正向影响。农户风险偏好对制度信任影响并不显著。基于此,研究提出吸纳社会资本参与,拓宽野生动物肇事保险资金来源,开展社区共管、地役权补偿等措施提升社区信任以及建立基于农户自主防护行为的野生动物肇事保险机制等政策建议。