Synthetic clonal reproduction through seeds

Cloning through seeds has potential revolutionary applications in agriculture, because it would allow vigorous hybrids to be propagated indefinitely. However, asexual seed formation or apomixis, avoiding meiosis and fertilization, is not found in the major food crops. To develop de novo synthesis of apomixis, we crossed Arabidopsis MiMe and dyad mutants that produce diploid clonal gametes to a strain whose chromosomes are engineered to be eliminated after fertilization. Up to 34% of the progeny were clones of their parent, demonstrating the conversion of clonal female or male gametes into seeds. We also show that first-generation cloned plants can be cloned again. Clonal reproduction through seeds can therefore be achieved in a sexual plant by manipulating two to four conserved genes.     

Differences between tight and loose cultures: a 33-nation study

With data from 33 nations, we illustrate the differences between cultures that are tight (have many strong norms and a low tolerance of deviant behavior) versus loose (have weak social norms and a high tolerance of deviant behavior). Tightness-looseness is part of a complex, loosely integrated multilevel system that comprises distal ecological and historical threats (e.g., high population density, resource scarcity, a history of territorial conflict, and disease and environmental threats), broad versus narrow socialization in societal institutions (e.g., autocracy, media regulations), the strength of everyday recurring situations, and micro-level psychological affordances (e.g., prevention self-guides, high regulatory strength, need for structure). This research advances knowledge that can foster cross-cultural understanding in a world of increasing global interdependence and has implications for modeling cultural change.     

Apple polyphenols extend the mean lifespan of Drosophila melanogaster

Apple polyphenols (AP) are an excellent source of dietary antioxidants. The present study investigated the effect of AP on the lifespan of fruit flies and their interaction with gene expressions of superoxide dismutase (SOD), catalase (CAT), methuselah (MTH), Rpn11, and cytochrome c oxidase (CcO) subunits III and VIb. Results showed the mean lifespan was significantly extended by 10% in fruit flies fed the AP diet. This was accompanied by up-regulation of genes SOD1, SOD2, and CAT and down-regulation of MTH in the aged fruit flies. Paraquat and H(2)O(2) challenge tests demonstrated that AP prolonged the survival time only for Oregon R wild type flies but not for SOD(n108) or Cat(n1) mutants, in which either SOD or CAT was knocked out. Chronic paraquat exposure could shorten the maximum lifespan from 68 to 31 days and reduce the climbing ability by 60%, whereas AP could partially reverse the paraquat-induced mortality and decline in climbing ability. AP could up-regulate Rpn11 at day 30, whereas it appeared to have no significant effect on gene expression of ubiquitinated protein, CcO subunits III and VIb. These AP-induced changes were unlikely associated with caloric restriction as the gustatory assay found no difference in average body weight and stomach redness index between the control and AP fruit flies. It was therefore concluded that the antiaging activity of AP was, at least in part, mediated by its interaction with genes SOD, CAT, MTH, and Rpn11.     

Inhibition of Lipopolysaccharide (LPS)-induced inflammatory responses by Sargassum hemiphyllum sulfated polysaccharide extract in RAW 264.7 macrophage cells

Sargassum hemiphyllum , a kind of brown seaweed generally found along coastlines in East Asia, has long served as a traditional Chinese medicine. S. hemiphyllum has shown an anti-inflammatory effect; however, its mechanism has not been elucidated clearly. This study explored S. hemiphyllum for its biomedical effects. S. hemiphyllum sulfated polysaccharide extract (SHSP) was first prepared; the mouse macrophage cell line (RAW 264.7) activated by lipopolysaccharide (LPS) was used as a model system. The secretion profiles of pro-inflammatory cytokines, including IL-1β, IL-6, TNF-α, and NO, were found significantly to be reduced in 1-5 mg/mL dose ranges of SHSP treatments. RT-PCR analysis suggested SHSP inhibits the LPS-induced mRNA expressions of IL-β, iNOS, and COX-2 in a dose-dependent manner. At protein levels, Western blot analysis demonstrated a similar result for NF-κB (p65) in cytosol/nuclear. Taken together, the anti-inflammatory properties of SHSP may be attributed to the down-regulation of NF-κB in nucleus.     

A decision-analytic approach to the optimal allocation of resources for endangered species consultation

The resources available to support conservation work, whether time or money, are limited. Decision makers need methods to help them identify the optimal allocation of limited resources to meet conservation goals, and decision analysis is uniquely suited to assist with the development of such methods. In recent years, a number of case studies have been described that examine optimal conservation decisions under fiscal constraints; here we develop methods to look at other types of constraints, including limited staff and regulatory deadlines. In the US, Section Seven consultation, an important component of protection under the federal Endangered Species Act, requires that federal agencies overseeing projects consult with federal biologists to avoid jeopardizing species. A benefit of consultation is negotiation of project modifications that lessen impacts on species, so staff time allocated to consultation supports conservation. However, some offices have experienced declining staff, potentially reducing the efficacy of consultation. This is true of the US Fish and Wildlife Service’s Washington Fish and Wildlife Office (WFWO) and its consultation work on federally-threatened bull trout (Salvelinus confluentus). To improve effectiveness, WFWO managers needed a tool to help allocate this work to maximize conservation benefits. We used a decision-analytic approach to score projects based on the value of staff time investment, and then identified an optimal decision rule for how scored projects would be allocated across bins, where projects in different bins received different time investments. We found that, given current staff, the optimal decision rule placed 80% of informal consultations (those where expected effects are beneficial, insignificant, or discountable) in a short bin where they would be completed without negotiating changes. The remaining 20% would be placed in a long bin, warranting an investment of seven days, including time for negotiation. For formal consultations (those where expected effects are significant), 82% of projects would be placed in a long bin, with an average time investment of 15 days. The WFWO is using this decision-support tool to help allocate staff time. Because workload allocation decisions are iterative, we describe a monitoring plan designed to increase the tool’s efficacy over time. This work has general application beyond Section Seven consultation, in that it provides a framework for efficient investment of staff time in conservation when such time is limited and when regulatory deadlines prevent an unconstrained approach.     

Relationship between soil structure and runoff/soil loss after 24 years of conservation tillage

A better understanding of tillage and stubble management effects on surface soil structure is vital for the development of effective soil conservation practices for the long-term. Relationships between aspects of soil structure and runoff/soil loss were investigated in 24 year old field experiment on an Oxic Paleustalf, in NSW, Australia. Two tillage/stubble management systems were compared, namely direct drilled/stubble retained (DD/SR) versus conventional tillage/stubble burnt (CC/SB). Tillage and stubble burning significantly increased bulk density and decreased the macro-aggregate stability, mean weight diameter (MWD), geometric mean diameter (GMD) and total porosity, particularly macroporosity (>60 μm). For the 0–5 cm layer, DD/SR had significantly higher water stability of macro-aggregates >2 mm than CC/SB (165 g/kg versus 78 g/kg), and the volume of pore space of diameter >60 μm at 0–5 cm depth was significantly greater (more than 11%) for DD/SR than for CC/SB. Under simulated rainfall (100 mm/h) and the removal of surface stubble, both runoff and soil loss were significantly higher under CC/SB compared to DD/SR. The infiltration rate at the end of the experiment under DD/SR was 3.7 times that of CC/SB (85 mm/h versus 23 mm/h). There were significant correlations between the proportion of soil particles >0.25 mm measured after wetting by rain and both final infiltration rate (P < 0.001) and soil loss (P < 0.001). It was concluded that 24 years of direct drilling and stubble retained practices significantly reduced runoff and soil erosion hazards, due to a fundamental change in soil structure, viz. higher soil aggregate stability and higher macroporosity of the surface soil.     

探索我国农业现代化进程中的新战略——北京市房山区窦店村的经验

农业现代化的内容具有鲜明的时间性,今天,由于自然对人类反冲力的剧增,使人类对大自然和自我认识发生了根本性的变革。因之,它的指导理论应增添新的学科——农业生态学。本文以北京市窦店村的现代化进程为例。阐述强化生态内容的必要性;对农业现代化的新内涵提出了自己的见解,指出生态农业若在生产条件、水平及效率等诸方面不能体现现代化便没有生命力;同时探讨了利用各种农业生态工程与技术予以强化的方式;最后谈到近十多年来工作中所得到的启示。     

Determination of total N-nitroso compounds by chemical denitrosation using CuCl

A method for the determination of total N-nitroso compounds (NOC) by chemical denitrosation and subsequent chemiluminescence detection of evolved NO is described. Denitrosation was accomplished with CuCl in HCl at 70 degrees C. The detection limit for N-nitrosoproline (NPRO) was 1 pmol. NO formation from NPRO was linear (R(2) = 0.999) from 4 pmol to 2 nmol. Among the possible interfering compounds tested, only S-nitroso compounds contribute any significant interference. This method had several advantages over other similar methods: (1) A commercially available one-piece reaction vessel and a NO analyzer with software were used. (2) NO release occurred rapidly and was easily measured and quantified. (3) Compared to HBr or HI, CuCl was more convenient to work with and safe. (4) CuCl was suitable for samples in aqueous and most organic solvents. The application of this method to food, personal care products, and human body fluids demonstrates its utility.     

A quality assurance program and quality assessment of the acidic precipitation in Ontario study (APIOS) deposition monitoring networks

Kinetics of H+ consumption by mineral dissolution in a surface soil and a subsoil of an acid woodland soil were studied by means of batch type experiments and stationary pH titrations. Mineral dissolution in the subsoil could effectively be described by congruent dissolution of illite (K_0.6Mg_0.25A1_2.3S1₃0₁₀(OH)₂) followed by an incongruent dissolution stage. In the incongruent stage the concentration of Al decreased while concentrations of K and Mg continued to increase. Congruent dissolution rates of illite could be predicted with power type relationships from transition state theory. In the incongruent dissolution stage the activities of H and Al appeared to be controlled by precipitation of A1(OH)₃. Results of this kind of experiments could be helpful to understand the behavior of Al and base cations in acid soils and soils with high atmospheric loadings of acid. Comparison of the results of batch experiments for a surface soil and a subsoil showed that initially proton consumption in the surface soil is faster and more effective due to the presence of a relatively high cation exchange capacity and base saturation value. However with progressive proton consumption and increasing reaction times proton consumption in the subsoil becomes faster than in the surface soil, presumably due to higher rates of mineral dissolution in the subsoil. Lower dissolution rates in the surface soil may result from lower contents of easily weatherable minerals, due to excessive leaching in the past which is reflected in a 17% lower acid neutralizing capacity than in the subsoil.