A novel genomic approach to herbicide and herbicide mode of action discovery

A herbicide with a new mode of action has not been commercialized for more than 30 years. A recent paper describes a novel genomic approach to herbicide and herbicide mode of action discovery. Analysis of a microbial gene cluster revealed that it encodes genes for both the biosynthetic pathway for production of the sesquiterpene aspterric acid and an aspterric acid‐resistant form of dihydroxy acid dehydratase (DHAD), its target enzyme. Aspterric acid is weak compared with commercial synthetic herbicides, and whether DHAD is a good herbicide target is unclear from this study. Nevertheless, this genomic approach provides a novel strategy for the discovery of herbicides with new modes action. © 2018 Society of Chemical Industry     

旋光法测定甲磺酸达氟沙星的含量

采用旋光法测定甲磺酸达氟沙星的含量,结果表明,在6～14 mg/mL浓度范围内,甲磺酸达氟沙星的旋光度与浓度呈良好的线性关系(r=0.999 8).与电位滴定法相比,本法具有简单、快速、易操作等优点.     

A photon turnstile dynamically regulated by one atom

Beyond traditional nonlinear optics with large numbers of atoms and photons, qualitatively new phenomena arise in a quantum regime of strong interactions between single atoms and photons. By using a microscopic optical resonator, we achieved such interactions and demonstrated a robust, efficient mechanism for the regulated transport of photons one by one. With critical coupling of the input light, a single atom within the resonator dynamically controls the cavity output conditioned on the photon number at the input, thereby functioning as a photon turnstile. We verified the transformation from a Poissonian to a sub-Poissonian photon stream by photon counting measurements of the input and output fields. The results have applications in quantum information science, including for controlled interactions of single light quanta and for scalable quantum processing on atom chips.     

施肥对马尾松人工幼林新鲜针叶及其林地枯枝落叶养分含量的影响

为了探明施肥对马尾松人工幼林新鲜针叶及其林地枯枝落叶养分含量的影响,在桂西北干热河谷地区选择4年生马尾松人工林建立固定样地,采用生物有机无机复混肥不同肥施量进行施肥试验,即A、B、C施肥量分别为1.0、1.5、2.0 kg/株以及CK（不施肥）,各3个重复试验。结果表明：（1）各施肥处理新鲜针叶的N、P、K元素含量分别比不施肥(CK)提高3.5%~40.7%,并大致显示出施肥量C＞B＞A的变化规律,其元素含量排序为N(11.710~16.480 g/kg)＞K或Ca(4.362~5.685 g/kg)＞Mg(1.323~1.430 g/kg)＞P(0.690~0.932 g/kg)＞Mn(0.243~0.268 g/kg)＞Fe(0.193~0.247 g/kg)＞Zn(0.016~0.024 g/kg)＞B(0.005~0.009 g/kg)＞Cu(0.003~0.004 g/kg)。（2）各施肥处理林地枯枝落叶的N、P、K元素含量分别比不施肥(CK)提高10.4%~49.9%,其元素含量排序为Ca(10.008~12.942 g/kg)＞N(6.357~7.281 g/kg)＞K或Mg(0.715~1.216 g/kg)＞Mn(0.391~0.740 g/kg)＞P(0.230~0.327 g/kg)＞Fe(0.210~0.253 g/kg)＞Zn(0.023~0.028 g/kg)＞B(0.008~0.012 g/kg)＞Cu(0.002~0.003 g/kg)。（3）马尾松人工幼林新鲜针叶及其林地枯枝落叶养分含量存在密切的相关性,其中新鲜针叶的N、P、K、Mg、Cu养分含量分别比林地枯枝落叶有所提高,而Ca、Zn、Fe、Mn、B养分含量则分别比林地枯枝落叶相应下降。     

香荚兰扦插繁育技术

充足的种苗供应是作物大规模生产的关键.本文综合香荚兰的引种栽培、田间实践与当地的环境条件等情况,总结了香荚兰扦插繁育过程中在场地、基质、苗床、插条的选择以及药剂处理、扦插方法、扦插后管理、病虫害防治等方面的技术要点,为香荚兰在广西的种苗繁育提供技术参考.     

Measuring asparagine synthetase activity in crude plant extracts

Asparagine synthetase B (AS) is the primary enzyme responsible for asparagine synthesis in plants. Routine biochemical studies of this enzyme's activity have been hindered by several problems including enzyme instability and rapid physiological turnover, endogenous inhibitors, competing pathways, and asparaginase activity. We describe an extraction procedure and assay conditions that provide a reliable, direct assay for the determination of AS activity in crude plant extracts. This assay performed well with several leguminous species and the enzyme preparation retained activity for up to 3 weeks when stored at -80 degrees C. Radio-HPLC detection enabled quantitative measurement of de novo aspargine synthesis in the extracts. Optimal activity was obtained with 1 mM glutamine and 10 mM ATP in the reaction assay. Aminooxyacetic acid (AOA, 1 mM) which prevents the assimilation of aspartate into the TCA cycle, was necessary to measure AS activity in peas, but not in lupine or soybean.     

Inventory of Emissions of Greenhouse Gases in Israel

As a Party to the United Nations Framework Convention on Climate Change, Israel is committed to develop a national inventory of anthropogenic emissions and removals of greenhouse gases. This paper presents the national inventory, which was developed according to the guidelines of the Intergovernmental Panel on Climate Change (IPCC). The inventory includes the following sectors: energy, industrial processes, agriculture, forestry and waste. In this paper, only the inventory of the direct greenhouse gases (CO₂, CH₄ and N₂O) is presented. Emissions of these gases were converted to CO₂ equivalent emissions by means of their Global Warming Potentials (a measure of the radiative effects of the different gases relatively to CO₂). CO₂ emissions from burning fossil fuels to produce energy are by far the largest source (50 million tons in 1996). The contribution of methane emissions from decomposition of landfilled municipal solid waste is second in importance (8 million tons of CO₂ equivalent). Industrial processes emit about 2 million tons CO₂ equivalent, the most important process being cement production. Agricultural emissions amount to about 2 million tons CO₂ equivalent and are due to soil emissions of nitrous oxide, methane emissions from enteric fermentation in domestic livestock and N₂O and CH₄ emissions from animal waste management. Although most forests in Israel are in a growing stage and atmospheric CO₂ is therefore removed to form biomass, this removal amounts to 0.4 million tons only and is very small as compared to emissions from other sectors. On a per capita basis, Israel's emissions of CO₂ from fuel combustion are not far behind those of some of the most developed countries.     

三维测量中相机镜头畸变修正算法的研究

作为逆向工程技术的必要手段,三维测量技术在工业和农业领域有着广泛的应用.利用图像识别技术捕捉曲面特征点三维坐标是三维测量的一种有效方法,而相机的镜头畸变是造成数字相机影像误差的主要原因之一.为了保证测量精度,必须对镜头畸变进行修正.在阐述镜头畸变类型的基础上,对相机镜头畸变的修正模型进行理论推导,并提出一种简单快捷的修正参数求解方法.     

Phytotoxic Eremophilanes from Ligularia macrophylla

Systematic bioassay-guided fractionation of the methylene chloride extract of the roots from Ligularia macrophylla was performed to identify both phytotoxic and antifungal compounds. Four phytotoxic eremophilanes (furanoeremophilan-14beta,6alpha-olide, 6beta-angeloyloxy-10beta-hydroxyfuranoeremophilane, eremophil-7(11)-ene-12,8alpha;14beta,6alpha-diolide, and 3alpha-angeloyloxybakkenolide A) and two antifungal fatty acids (linoleic acid and alpha-linolenic acid) were isolated. The X-ray crystal structure determination of 6beta-angeloyloxy-10beta-hydroxyfuranoeremophilane is reported here for the first time. All four eremophilanes substantially inhibited growth of the monocot Agrostis stolonifera (bentgrass) while demonstrating little activity against the dicot Lactuca sativa (lettuce) at 1000 microM. In a dose-response screening of all compounds for growth inhibitory activity against Lemna paucicostata, 6beta-angeloyloxy-10beta-hydroxyfuranoeremophilane was the most active with an IC50 of 2.94+/-0.16 microM. This compound also caused the greatest reduction of photosynthetic electron flow; however, its mode of action remains to be determined. Evaluation of isolated compounds for activity against the Formosan subterranean termite, Coptotermes formosanus, is also reported. At a concentration of 0.5% (wt/wt), 6beta-angeloyloxy-10beta-hydroxyfuranoeremophilane significantly reduced the consumption of filter paper by C. formosanus.     

Hydroquinone antioxidants from the Indian ocean tunicate Aplidium savignyi.

Three hydroquinone compounds have been isolated from the Indian Ocean tunicate Aplidium savignyi. Two are already known: geranylhydroquinone and the 2-(3-hydroxy-3,7-dimethyloct-6-enyl)-1,4-benzenediol as a new stereoisomer 2-(2Z)-(3-hydroxy-3, 7-dimethyloct-2,6-dienyl)-1,4-benzenediol. The structures were determined using spectroscopic data ((1)H NMR, (13)C NMR, MS, UV, and IR). These compounds are potential natural antioxidants.