Seed dormancy: breaking by uncouplers and inhibitios of oxidative phosphorylation

When 2,4-dinitrophenol and carbon dioxide were applied together to dormant seeds of Trifolium subterraneum L. (subterranean clover), 2,4-dinitrophenol did not disturb the breaking of dormancy which carbon dioxide usually induces in legume seeds. On the contrary, on its own, it promoted germination in a substantial proportion of seeds; a similar effect was produced by other uncouplers or inhibitors of oxidative phosphorylation.     

Participation of an intermediate of oxidative phosphorylation in ion accumulation by mitochondria

Heart mitochondria accumulate massive amounts of Mg(++) and phosphate or Ca(++) and phosphate when incubated under appropriate conditions. Studies with inhibitors of respiration, oligomycin, and uncouplers of oxidative phosphorylation indicate that the energy necessary for these reactions may be provided either in the form of ATP in the absence of electron transport, or in the form of a high-energy intermediate of oxidative phosphorylation, which operates even though ATP is not produced.     

2-甲基异茨醇对斑马鱼氧化磷酸化及免疫相关基因表达的影响

-甲基异茨醇（2-methylisoborneol, 2-MIB）是由多种放线菌土壤生物、蓝细菌等产生的一种挥发性有机物,在水体中广泛存在。2-MIB除了导致鱼类土腥味以外,是否对鱼类造成其它影响尚不得而知。本研究将斑马鱼饲养在2-MIB浓度为42ng/L的水中24h后,进行鳃组织的转录组测序分析,发现2-MIB处理组中有163个基因显著上调,565个基因显著下调。KEGG通路富集显示氧化磷酸化相关的生化过程上调,而免疫相关信号通路发生下调, RT-qPCR进一步显示,2-MIB显著上调氧化磷酸化相关基因ndufb7、mt-cyb、mt-nd4、mt-nd6、mt-co2和mt-atp6的表达,而Toll-like receptor signaling pathway相关免疫基因rela、cd40、ikbkb、mapk8b、mapk3、ripk1l显著下调。超氧化物歧化酶SOD活性在2-MIB暴露后,鳃和肝脏组织中的SOD升高。本研究表明水体中的2-MIB会提高鱼体内活性氧水平,引起细胞损伤,还可能导致相关免疫机能下降。     

Cyclic nucleotide phosphodiesterase in Dictyostelium discoideum: interconversion of two enzyme forms

An extracellular cyclic nucleotide phosphodiesterase was isolated from either growing cultures or aggregating amoebas of Dictyostelium discoideum. The enzyme is released in a form with a low Michaelis constant (15 micromolar) and spontaneously undergoes a slow conversion to a less active form with a high Michaelis constant (2 mnillimolar). Inactivation was prevented or reversed by use of Cleland's reagent, dithiothreitol. The two enzyme forms may be part of a mechanism for control of concentration of cyclic adenosine monophosphate.     

DDT: participation in ultraviolet-detectable, charge-transfer complexation

The chlorophenyl groups of DDT and several of its metabolites are capable of participating in a charge-transfer interaction with tetracyanoethylene detectable in the ultraviolet region of the spectrum. In addition, during a change of state DDT undergoes ultraviolet spectral alterations that closely resemble those previously claimed to support the hypothesis suggesting charge-transfer interaction between this pesticide and a component of insect nerve tissue. The pesticide DDT possesses structural characteristics that would permit it to participate in several types of molecular association.     

Prebiotic synthesis: phosphorylation in aqueous solution

Formation of uridine-5'-phosphate from uridine and inorganic phosphate in aqueous solution is effected by the following condensing agents: cyanogen, cyanoformamide, cyanate, cyanamide, thioformate, ethylisocyanide, and a watersoluble carbodiimide. The yields are always small, even when a large excess of condensing agent is used. The cyclization of uridine-3'-(2')-phosphate occurs under the same conditions but in much greater yield.     

Lignification in trees: indication of exclusive peroxidase participation

Syringaldazine did not turn purple on cross sections of tree branches or saplings or on cambial tissue cultures unless hydrogen peroxide was added; this indicated the absence of laccase but presence of peroxidase in lignifying cells. Peroxidase, therefore, apparently is the only en enzyme that polymerizes p-coumaryl alcohols to lignin in trees.     

Fullerene isomerism: isolation of c2v,-c78 and d3-c78

Early reports on the formation of the higher fullerenes C(76), C(78), C(84), C(90), and C(94) by resistive heating of graphite stimulated theoretical calculations of possible cage structures for these all-carbon molecules. Among the five fullerene structures with isolated pentagons found for C(78), a closed-shell D3h-isomer was predicted to form preferentially. Two distinct C(78)-isomers were formed in a ratio of approximately 5:1 and could be separated by high-performance liquid chromatography. The carbon-13 nuclear magnetic resonance (NMR) spectrum of the major isomer is uniquely consistent with a C2v-structure. The NMR data also support a chiral D(3)-structure for the minor isomer. The isolation of specifically these two isomers of C(78) provides insight into the stability of higher fullerene structures and into the mechanism for fullerene formation in general.     

紫花苜蓿肽基脯氨酰顺反异构酶基因全长cDNA的电子克隆及同源建模

[目的]研究对紫花苜蓿肽基脯氨酰顺反异构酶基因全长cDNA进行电子克隆及同源建模的方法。[方法]根据物种间同源基因相对保守的特点,利用NCBI数据库,对公共EST数据库进行同源检索筛选和重叠群装配,获得拼接cDNA序列,经过ORFFinder分析后获得相应蛋白质的全长序列,并利用Swiss-Mode服务器预测各原子坐标,进而利用Swiss-PdbViewer生成三维空间模型。[结果]采用该方法成功获得紫花苜蓿肽基脯氨酰顺反异构酶基因的完整cDNA序列,全长为1880bp,mPPI蛋白质编码68AA,分子量约为7829.9Da,理论等电点pI=8.99,原子组成为C338H547N103O103S4,摩尔消光系数280nm处为4595,不稳定系数为42.16,脂肪系数为83.24,总平均亲水性为-0.456。[结论]根据物种间同源基因序列对跨物种间EST数据库进行同源检索筛选和拼接,是基因克隆的一条有效途径。     

Community food security: Salience and participation at community level

Community food security (CFS) is an incipient movement based on the re-localization of many food system activities in response to values concerning the social, health, economic, and environmental consequences of the globalizing food system. This study examines the salience of these values based on the action agendas and accomplishments emerging from community planning events in six rural counties of New York, and the nature and type of participation and local support. The study finds a high level of agreement between CFS values as articulated by national leaders in this incipient movement and the action agendas. Further evidence of the salience of these themes is seen in the levels and types of activities and accomplishments taking place 8--12 months after the planning events. However, these follow-through activities appear to have been impeded by a variety of government regulations, uneven levels of support from community organizations and agencies, and a policy environment of fiscal austerity, narrow outcome-oriented accountability, and allocation of agency staff toward special-purpose grants and contracts. Many of these constraints are likely to exist in other communities and are beyond the scope of what community volunteers and practitioners can be expected to address on their own.     

饲粮添加不同水平果胶寡糖螯合锌对肉仔鸡生长性能、免疫功能和血清抗氧化功能的影响

目的探讨亚甲基水杨酸杆菌肽对断奶仔兔血清和肠道组织抗氧化指标的影响。方法将300只35日龄断奶的新西兰白兔根据不同饲粮添加成分,分为5个处理组,分别是亚甲基水杨酸杆菌肽(BMD)高、中、低剂量添加组(100、50、25 mg/kg),杆菌肽锌(BZ)对照组(50 mg/kg)、空白对照组(无添加)。饲喂35 d后测定血液和肠道中抗氧化功能相关指标。结果与空白对照组相比,BMD和BZ显著提高了血清和肠道中总抗氧化能力(T-AOC)和超氧化物歧化酶(SOD)活性(P<0.05),显著降低了丙二醛(MDA)含量(P<0.05),BMD组和BZ组无统计学差异(P>0.05)。结论日粮中添加BMD可提高断奶仔兔的抗氧化功能,且以100 mg/kg的添加量最适宜。     

Inquiry for the public good: Democratic participation in agricultural research

In recent decades, constituenciesserved by land-grant agricultural research haveexperienced significant demographic and politicalchanges, yet most research institutions have not fullyresponded to address the concerns of a changingclientele base. Thus, we have seen continuingcontroversies over technologies produced by land-grantagricultural research. While a number of scholars havecalled for a more participatory agricultural scienceestablishment, we understand little about the processof enhancing and institutionalizing participation inthe US agricultural research enterprise. We firstexamine some of the important issues surroundingcitizen participation in science and technologypolicy. We then review and assess variousinstitutional mechanisms for participation that havebeen implemented in diverse settings by institutionsof science and technology. Based on evidence from theexperiences of these institutions, we argue that acloser approximation of the ‘public good’ can beachieved by encouraging the participation of thefullest range possible of constituents as an integralpart of the process of setting research priorities.     

食品安全风险治理中的公众参与意愿：影响机制与提升策略

为提升公众食品安全风险治理参与意愿,基于扩展的计划行为理论和态度-情境-行为理论构建分析框架,借助微观调查数据,采用结构方程模型、Bootstrap中介效应检验法和分层回归法对公众食品安全治理参与意愿的影响机制进行实证研究。结果表明：1）行为态度、主观规范、知觉行为控制、感知风险和过去经历对公众食品安全治理参与意愿有显著正向影响;2）行为态度在感知风险、过去经历与参与意愿关系中发挥中介作用;3）政策规制在行为态度与参与意愿关系中发挥调节作用。因此,应从提高公众食品安全风险认知、优化公众食品安全治理参与体验、改善公众食品安全治理参与态度、营造促进公众参与的政策环境等方面提升公众食品安全风险治理参与意愿,推进食品安全风险社会共治。     

Stakeholder participation in agricultural research projects: a conceptual framework for reflection and decision-making

Recent discourse in the field of participatory agricultural research has focused on how to blend various forms and intensities of stakeholder participation with quality agricultural science, moving beyond the simple “farmer-first” ideology of the 1980s and early 1990s. Yet, most existing frameworks of participation in agricultural research still adhere to a linear typology of participatory research with an inherent claim of “the more participation, the better.” In this article, we propose a new framework that looks at participatory research elements along different dimensions and attributes and thus takes into account the diversity and dynamics of agricultural research projects. The framework provides a basis for agricultural researchers engaged in participatory processes with local stakeholders to decide for which issues and in which phases certain participatory elements could be used in a specific research context. Rather than aiming at maximizing the adoption of participatory methods, it can thus become a tool for optimizing the use of participatory approaches in agricultural research. We conclude that this framework can be a starting point for a more thoughtful integration of participatory elements in agricultural research projects that does justice to the multidimensional and dynamic nature of stakeholder participation in varying contexts.     

Watered-down democratization: modernization versus social participation in water management in Northeast Brazil

This article examines social participation in water management in the Jaguaribe Valley, state of Ceará, Northeast Brazil. It argues that participatory approaches are heavily influenced by the general ideological and symbolic contexts in which they occur, that is, by how participants understand (or misunderstand) what is taking place, and associate specific meanings to things and events. An analysis of these symbolic factors at work sheds light on the potentialities of and limitations on participatory experiences not accounted for in usual structural analyses. In the particular case of Ceará, this article describes how the idea of modernization, which is so pervasive in the ways economic development is presented in Brazil, provides a frame against which other meanings are constructed. In water management arenas, the presentation of participation as an aspect of the general modernization of the state has reorganized meanings and delegitimized some forms of knowledge and economic activities to the detriment of others. As a result, the promotion of equality through participation lost a great deal of efficacy, and this state of affairs provided some degree of social validation for asymmetries in participatory decision making processes.