Long-lasting systematic roguing for effective management of CABMV in passion flower orchards through maintenance of separated plants

In Brazil, passion flower is grown across almost the entire country. The predominant disease of the passion flower crop is passion fruit woodiness, caused by the potyvirus cowpea aphid-borne mosaic virus (CABMV), and transmitted by aphids in a nonpersistent manner. The disease reduces the useful life of the orchard from 36 months to approximately 18 months. Up to now, there has not been an efficient method for disease management. The aim of this work was to evaluate the efficiency of systematic roguing of diseased plants through weekly inspections, for disease management in the field. The latent and incubation periods of CABMV in passion flower vines were determined in order to optimize roguing efficiency. Passion fruit plants inoculated with CABMV started to act as sources of inoculum from 3 days after inoculation (DAI), and the symptoms were expressed, on average, at 8 DAI. Five field experiments, conducted in the states of São Paulo and Bahia, Brazil, demonstrated that systematic roguing of diseased plants was significantly efficient for managing passion fruit woodiness disease. In order to facilitate identification and subsequent removal of the infected plants, they need to be grown separately. This cultural practice can be recommended for managing passion fruit woodiness disease, provided it is applied on a regional scale by all passion fruit growers. The development of some pilot plantings for the application of roguing in a passion flower-producing region is recommended to validate the use of this technique for managing passion fruit woodiness disease.     

Interaction of phosphodiesterase 5 inhibitor with malathion on rat brain mitochondrial-bound hexokinase activity

The main objective of this study was to investigate the possible protective effect of pentoxifylline as a phosphodiesterase 5 inhibitor used as a cardiovascular medication on malathion-induced changes on rat mitochondrial-bound hexokinase activity.Animals in four various groups received moderate toxic dose of malathion (200 mg/kg/day), effective dose of pentoxifylline (50 mg/kg/day) alone and in combination, and the control group that received only vehicle. All administrations were done intraperitoneally for one week. At the end of the experiment, the brain was removed and the mitochondria were isolated. Hexokinase (HK) activity, cellular lipid peroxidation (LPO) and total antioxidant capacity (TAC) were analyzed in brain mitochondria.Malathion noticeably decreased TAC and increased HK activity and LPO in the mitochondria whereas pentoxifylline significantly restored malathion-induced changes in LPO, HK, and TAC.The results of the present study indicate that phosphodiesterase 5 inhibition remarkably protects brain mitochondria from malathion-induced changes on HK activity and oxidative stress.     

Interaction of phosphodiesterase 5 inhibitor with malathion on rat brain mitochondrial-bound hexokinase activity

The main objective of this study was to investigate the possible protective effect of pentoxifylline as a phosphodiesterase 5 inhibitor used as a cardiovascular medication on malathion-induced changes on rat mitochondrial-bound hexokinase activity.Animals in four various groups received moderate toxic dose of malathion (200 mg/kg/day), effective dose of pentoxifylline (50 mg/kg/day) alone and in combination, and the control group that received only vehicle. All administrations were done intraperitoneally for one week. At the end of the experiment, the brain was removed and the mitochondria were isolated. Hexokinase (HK) activity, cellular lipid peroxidation (LPO) and total antioxidant capacity (TAC) were analyzed in brain mitochondria.Malathion noticeably decreased TAC and increased HK activity and LPO in the mitochondria whereas pentoxifylline significantly restored malathion-induced changes in LPO, HK, and TAC.The results of the present study indicate that phosphodiesterase 5 inhibition remarkably protects brain mitochondria from malathion-induced changes on HK activity and oxidative stress.     

Simulation of mefenacet concentrations in paddy fields by an improved PCPF-1 model

An improved simulation model (PCPF-1) has been evaluated for the prediction of the fate of mefenacet in an experimental paddy field. This model simulates the fate and transport of pesticide in paddy water and the top 1 cm of paddy soil. Observed concentrations of mefenacet in the paddy water and the surface soil exponentially decreased from their maximum concentrations of 0.70 mg litre(-1) and 11.3 mg kg(-1), respectively. Predicted mefenacet concentrations both in the water and surface soil were in excellent agreement with those measured during the first 2 weeks after herbicide application, but concentrations in paddy water were appreciably overestimated thereafter. The model simulated mefenacet losses through runoff, percolation and degradation to be respectively 41.9%, 6.4% and 57.3% of applied, and the mass balance error was about -6%. The model simulation implied that drainage and seepage control, especially shortly after application when herbicide concentrations are high, is essential for preventing pesticide losses from paddy fields. In focusing on pesticide concentrations in this early period the PCPF-1 model can be a beneficial tool for risk assessment of pesticide losses and in the evaluation of agricultural management for reducing pesticide pollution associated with paddy rice production.     

Investigating spatial and temporal variations of soil moisture content in an arid mining area using an improved thermal inertia model

Mining operations can usually lead to environmental deteriorations. Underground mining activities could cause an extensive decrease in groundwater level and thus a dramatic variation in soil moisture content(SMC). In this study, the spatial and temporal variations of SMC from 2001 to 2015 at two spatial scales(i.e., the Shendong coal mining area and the Daliuta Coal Mine) were analyzed using an improved thermal inertia model with a long-term series of Landsat TM/OLI(TM=Thematic Mapper and OLI=Operational Land Imager) data. Our results show that at large spatial scale(the Shendong coal mining area), underground mining activities had insignificant negative impacts on SMC and that at small spatial scale(the Daliuta Coal Mine), underground mining activities had significant negative impacts on SMC. Trend analysis of SMC demonstrated that areas with decreasing trend of SMC were mainly distributed in the mined area, indicating that underground mining is a primary cause for the drying trend in the mining region in this arid environment.     

旅游能源消耗模型及海南省实证研究

旅游过程消耗的化石能源产生一定的环境问题,为了促进区域旅游可持续发展,旅游能源消耗必须严格限定在门槛水平之下。文中在构建旅游能源消耗模型的基础上,以海南省为例进行了实证分析,分别对旅游交通、旅游住宿、旅游活动等旅游部门的能源消耗进行了定量化计算,并对旅游能源消耗的部门结构、总量特征进行了归纳总结。从区域横向对比看,2012年海南省旅游能耗的部门结构和人均值与澎湖列岛、新西兰具有不同的分布特征,体现了三个旅游地在客源地空间结构、产品丰度、能耗强度、旅游者平均距离等方面的差异。     

耦合融雪的新安江模型在干旱区径流模拟研究

在西营河九条岭站以上流域内,利用2011—2018年格点降水和气温数据集的逐日资料,通过降水径流成因关系探索出格点降水异常点修正方法,并将融雪模块与三水源新安江模型耦合,研究流域日径流模拟过程.采用确定性系数和相对误差两个评估准则进行模拟效果的评价,将降水修正后以及融雪耦合后的模拟效果与未改进的模型模拟效果进行比较,分...     

A bio-economic model of long-run Striga control with an application to subsistence farming in Mali

A bio-economic model of Striga control is developed and applied to Mali's Mourdiah Zone. Various constraints are added, and optimal production practices identified based on Striga infestation levels, rainfall levels, and economic parameters. Model optimization suggests efforts to suppress Striga with nitrogen applications are both expensive and risky. The efficacy of hand-pulling Striga in reducing the Striga seedbank depends on Striga infestation levels and climatic conditions, as does the profitability of hiring labour to expand cultivated acreage. Under all climatic conditions and infestation levels considered, millet in a pure stand generated greater expected net returns than a millet - groundnut or millet - cowpea association. Under conditions of low rainfall, the model suggests planting millet at a density of 0.5 hills m^?2. With average or higher rainfall, the model suggests planting millet at a density of 3.5 hills m^?2. Estimates of Striga-induced net revenue losses also vary with climatic conditions, ranging from 6% to 85%. Model results are encouraged to be used as a guide in the design and evaluation of research and extension programmes aimed at identifying long-run Striga control strategies and promoting their adoption.     

Characterization and biological activity of flavonoids from ripe fruit of an anthracnose-resistant blueberry cultivar

Anthracnose fruit rot, caused by Colletotrichum acutatum, is among the most important diseases of blueberries. Most cultivars are susceptible but ‘Elliott’ is resistant. Our objective was to identify possible antifungal compounds that play a role in the resistance response. Chemical fractions from freeze-dried, ripe fruit of ‘Elliott’ and a susceptible cultivar (Jersey) were extracted with methanol and ethyl acetate. Extracts were screened on solid media for suppression of microconidiation of C. acutatum. The methanolic extract was fractionated and the soluble methanolic fraction from ‘Elliott’ was the most biologically active. This fraction was dried, dissolved in water, and screened in vivo by pre-treating ripe ‘Jersey’ fruit with 0.5, 1, 2, and 4% solutions (w/v) and subsequently inoculating the fruit with C. acutatum. An 88% reduction in infection incidence was observed after 12 days with the 4% solution. Anthocyanins and other flavonoids were then quantified in fruit of the two cultivars using HPLC-MS. ‘Elliott’ fruit contained more anthocyanins (4.87 mg/g of freeze-dried tissue) than ‘Jersey’ (3.27 mg/g of freeze-dried tissue); however, the same compounds were found in both cultivars. ‘Elliott’ fruit also contained more non-anthocyanin flavonoids (0.18 mg/g of freeze-dried tissue) than ‘Jersey’ (0.12 mg/g of freeze-dried tissue), including two distinctive compounds in ‘Elliott’. The non-anthocyanin flavonoid fractions of both ‘Elliott’ and ‘Jersey’ significantly decreased the growth of C. acutatum in a liquid bioassay but the effect was more pronounced in the ‘Elliott’ fraction. The two distinctive compounds in ‘Elliott’ were further characterized by MS/MS and were identified as quercetin 3-O-rhamnoside and, putatively, syringetin rhamnoside. Additionally, we evaluated ‘Elliott’ and ‘Jersey’ methanolic extracts for their ability to inhibit lipid peroxidation, and the extract obtained from ‘Elliott’ was almost twice as active at inhibiting peroxidation. These results provide new insights into the role of antifungal compounds in the resistance response of ripe ‘Elliott’ blueberries to infection by C. acutatum.     

基于云模型的西安市蔬菜区土壤肥力综合评价

土壤肥力对于维持农作物生长和保障土地生产力具有重要意义。为综合考虑土壤肥力评价中的模糊性和随机性,引入云模型对西安市蔬菜区土壤肥力状况进行综合评价,选取pH值、有机质、碱解氮、有效磷和速效钾为评价指标,运用主成分分析确定权重,利用逆向云、正向云算法获得每个指标的云模型;根据单指标云模型特征值和权重值,结合综合云算法得到土壤肥力综合评价云模型。结果表明:西安市蔬菜区土壤养分总体上属于中等偏高水平,有效磷、速效钾含量偏高,碱解氮含量适中。土壤有机质是土壤肥力的首要限制因素,在实际生产过程中应注意增施有机肥,高磷、高钾地区应限制磷肥、钾肥的使用,按需施用氮肥。科学评价土壤肥力有助于更加准确地掌握土壤特性和养分状况,精准施肥,维持土壤养分平衡,提高土壤质量。     

Evaluation of an erosion-sediment transport model for a hillslope using laboratory flume data

Climate change can escalate rainfall intensity and cause further increase in sediment transport in arid lands which in turn can adversely affect water quality. Hence, there is a strong need to predict the fate of sediments in order to provide measures for sound erosion control and water quality management. The presence of microtopography on hillslopes influences processes of runoff generation and erosion, which should be taken into account to achieve more accurate modelling results. This study presents a physically based mathematical model for erosion and sediment transport coupled to one-dimensional overland flow equations that simulate rainfall-runoff generation on the rill and interrill areas of a bare hillslope. Modelling effort at such a fine resolution considering the flow connection between interrill areas and rills is rarely verified. The developed model was applied on a set of data gathered from an experimental setup where a 650 cm×136 cm erosion flume was pre-formed with a longitudinal rill and interrill having a plane geometry and was equipped with a rainfall simulator that reproduces natural rainfall characteristics. The flume can be given both longitudinal and lateral slope directions. For calibration and validation, the model was applied on the experimental results obtained from the setup of the flume having 5% lateral and 10% longitudinal slope directions under rainfall intensities of 105 and 45 mm/h, respectively. Calibration showed that the model was able to produce good results based on the R2(0.84) and NSE(0.80) values. The model performance was further tested through validation which also produced good statistics(R2=0.83, NSE=0.72). Results in terms of the sedigraphs, cumulative mass curves and performance statistics suggest that the model can be a useful and an important step towards verifying and improving mathematical models of erosion and sediment transport.     

Effects of diazinon on the activity and gene expression of mitochondrial glutamate dehydrogenase from rat pancreatic Langerhans islets

The main propose of the present study was to determine the effects of diazinon on the activity and gene expression of glutamate dehydrogenase (GDH) as the key enzyme of Langerhans islet for secretion of insulin. Diazinon was administered intraperitoneally at doses of 15, 30, and 60 mg/kg. Langerhans islets were isolated from the pancreas of rats by a standard collagenase digestion, separation by centrifugation, and hand-picking technique. The activity and gene expression of the mitochondrial GDH was determined in the islets homogenates. Glutamate, C-peptide, and insulin were determined in plasma.Diazinon at all tested doses (15, 30, and 60 mg/kg) significantly (p < 0.01) decreased plasma insulin after 1 h while the values did not differ from control when examined after 18 h. Diazinon at all tested doses (15, 30, and 60 mg/kg) significantly (p < 0.01) increased concentration of C-peptide both 1 and 18 h post-administration. Diazinon at all tested doses (15, 30, and 60 mg/kg) significantly (p < 0.05) increased production of glutamate while the values did not differ from control when tested after 18 h. Administration of diazinon at doses of 30 and 60 mg/kg significantly (p < 0.001) increased activity of GDH after 1 h while all doses of diazinon increased GDH activity when measured after 18 h. Diazinon at dose of 60 mg/kg significantly (p < 0.01) decreased expression of GDH gene 18 h post-administration.It is concluded that GDH is a component of diazinon-induced changes in release of improper insulin.     

Identification and activity of ethyl gallate as an antimicrobial compound produced by Geranium carolinianum

We isolated an antimicrobial compound from the aerial tissue of Geranium carolinianum and identified it as ethyl 3, 4, 5-trihydroxy benzoate (ethyl gallate) by ¹H-NMR and ¹³C-NMR and gas chromatography–mass spectrometry. The antimicrobial activity of ethyl gallate against three potato pathogens was assayed by the paper disk method. The activity against Ralstonia solanacerum , Streptomyces scabies , and Streptomyces acidiscabies was observed at concentrations >200, >300, and >300 µg disk⁻¹, respectively. These results suggest that the antimicrobial activity of Geranium carolinianum against soil-borne plant disease pathogens is partly related to ethyl gallate.     

葡萄乙醛脱氢酶VvALDH10A9基因的克隆、表达及酶活性分析

由葡萄座腔菌科Botryosphaeriaceae真菌引起的葡萄溃疡病Botryosphaeria dieback是葡萄上的主要枝干病害,严重影响葡萄产量和品质。鉴定和分析参与葡萄与葡萄溃疡病菌互作的基因,有助于揭示和阐明葡萄抗溃疡病的信号通路。本研究根据葡萄溃疡病菌侵染后的葡萄转录组数据信息,利用逆转录聚合酶链式反应技术(RTPCR)克隆了一个受葡萄溃疡病菌诱导上调表达的乙醛脱氢酶基因VvALDH10A9(Vitis vinifera aldehyde dehydrogenase 10A9)。系统进化树分析表明,该基因编码的蛋白与拟南芥AtALDH10A8亲缘关系最近。利用实时荧光定量PCR分析VvALDH10A9的表达结果表明:VvALDH10A9的表达具有组织特异性,在茎、叶和花中表达量最高,在根中表达量相对较低;葡萄溃疡病菌侵染后,VvALDH10A9在葡萄抗病品种中表达变化不明显,而在葡萄感病品种中该基因显著上调表达。利用原核蛋白表达系统诱导合成的VvALDH10A9蛋白,经纯化后可降解乙醛,表明VvALDH10A9蛋白具有乙醛脱氢酶活性。     

Implementation of a herbicide simulation model in a geographical information system with an example of a site-specific application

A Geographical Information System (GIS) was combined with a model for simulating leaching and degradation of herbicides. The model uses first–order kinetics to simulate degradation, and a cascade model to simulate transport. This system was tested with data from a 16 km² research catchment in northern Germany. Geometrical, topological, and soil data of this area were stored in a GIS. For the whole area, divided into small homogeneous sites (ecotopes), model runs were carried out. The system is able to handle data for all ecotopes automatically and to present calculated results on the behaviour of herbicides as distributed over time and depth for the area. An application of ethofumesate made in sugar–beet in spring and recropping of winter wheat after beet harvest was modelled. Degradation/sorption parameters were estimated from similar soils. Simulation results showed slower degradation in the sandy sites of the catchment, compared to the more loamy regions. Residues of herbicide remaining after beet harvest were greater than 20% of the applied dose in the sandy soils after 150 days. Hence, high risk of damage to the following crop of winter wheat was predicted. At the other sites residues remaining were between 2% and 20% of the applied dose. Einbindung eines Simulationsmodells zum Herbizidverhalten in ein Geographisches Informationssystem–Beispiel zur schlagspezifischen Anwendung Ein Geographisches Informationssystem (GIS) wurde mit einem Simulationsmodell für Herbizidabbau und –einwaschung kombiniert. Grundlage der Abbausimulation ist eine Kinetik 1. Ordnung, der Transport im Boden wird mit Hilfe eines Kaskadenmodells berechnet. Das System wurde in einem Intensiv–Untersuchungsgebiet (16 km²) in Norddeutschland getestet. Geometrische und topologische Daten der Fläche sowie Bodendaten sind im GIS gespeichert. Für die gesamte Fläche, die in kleine homogene Teilflächen (Ökotope) aufgeteilt wurde, wurden Simulationsberechnungen durchgeführt. Das System ist in der Lage, Daten für alle Ökotope automatisch bereitzustellen und die Ergebnisse zum Einwaschungs– und Abbauverhalten für die gesamte Fläche in ihrer Verteilung über Zeit und Tiefe darzustellen. Als Szenario wurde die Applikation von Ethofumesat in Zuckerrüben im Frühjahr mit einem Nachbau von Winterweizen nach der Rübenemte gewählt. Abbauund Sorptionsparameter waren in ähnlichen Böden ermittelt worden. Die Simulationsergebnisse zeigten einen langsameren Abbau in den sandigen Böden verglichen mit den lehmigen. In den sandigen Böden lagen die Rückstandsgehalte nach 150 Tagen übe 20 % der Ausgangskonzentration, wodurch ein hohes Nachbaurisiko für Winterweizen prognostiziert wurde. Für den Rest der Fläche lagen die Rückstände zwischen 2% und 20% der Ausgangskonzentration.     

Comparison of the inhibition effect of different anticoagulants on vitamin K epoxide reductase activity from warfarin-susceptible and resistant rat

Anti-vitamin K drugs are widely used as anticoagulant in human thromboembolic diseases. Similar compounds have also been used as rodenticides to control rodent population since 1950s. Massive use of first generation anticoagulants, especially warfarin, has lead to the development of genetic resistances in rodents. Similar resistances have been reported in human. In both cases, polymorphisms in VKORC1 (Vitamin K epoxide reductase subunit 1), the subunit 1 of the VKOR (Vitamin K epoxide reductase) complex, were involved. In rats (Rattus norvegicus), the Y139F mutation confers a high degree of resistance to warfarin. Little is known about the in vitro consequences of Y139F mutation on inhibitory effect of different anticoagulants available. A warfarin-susceptible and a warfarin-resistant Y139F strain of wild rats (Rattus norvegicus) are maintained in enclosures of the Lyon College of Veterinary Medicine (France). Using liver microsomes from susceptible or resistant rats, we studied inhibition parameters by warfarin (K_i = 0.72 ± 0.1 μM; 29 ± 4.1 μM), chlorophacinone (K_i = 0.08 ± 0.01 μM; 1.6 ± 0.1 μM), diphacinone (K_i = 0.07 ± 0.01 μM; 5.0 ± 0.8 μM), coumachlor (K_i = 0.12 ± 0.02 μM; 1.9 ± 0.2 μM), coumatetralyl (K_i = 0.13 ± 0.02 μM; 3.1 ± 0.4 μM), difenacoum (K_i = 0.07 ± 0.01 μM; 0.26 ± 0.02 μM), bromadiolone (K_i = 0.13 ± 0.02 μM; 0.91 ± 0.07 μM), and brodifacoum (K_i = 0.04 ± 0.01 μM; 0.09 ± 0.01 μM) on VKOR activity. Analysis of the results leads us to highlight different anticoagulant structural elements, which influence inhibition parameters in both susceptible and Y139F resistant rats.