Insect repellent/antifeedant activity of 2,4-methanoproline and derivatives against a leaf- and seed-feeding pest insect   总被引：1，自引：0，他引：1  

Stevens CV  Smagghe G  Rammeloo T  De Kimpe N 《Journal of agricultural and food chemistry》2005,53(6):1945-1948

2,4-methanoproline is a natural product isolated from the seeds of Ateleia herbert smithii Pittier that was formerly suggested to have insect repellent/antifeedant activity; however, this was not tested quantitatively. In this study the insect repellent/antifeedant potency of methanoproline was measured against larvae of the cotton leafworm, Spodoptera littoralis (Boisd.), and adults of the cowpea weevil, Callosobruchus maculatus (F.). In addition, several N-alkyl, amino, and nitrile derivatives of methanoproline with varying stereodemanding substituents were synthesized and also tested. It was shown that in S. littoralis methanoproline itself did not show any significant activity but that derivatives 5, 7, 8, and 10 did show a reasonable repulsive/antifeedant activity that was comparable to the commercial repellent DEET. A significant repellent activity was scored for methanoproline in adults of C. maculatus that was similar to DEET.  相似文献   

Retention of Staphylococci and Total Coliforms During Wastewater Percolation Through Equatorial Soil in Central Africa: The Role of the Soil Column Near Soil Surface and that Closely Above Groundwater Table     

Moïse Nola  Thomas Njiné  Norbert Kemka  Serge H. Zébazé Togouet  Samuel Foto Menbohan  Adolphe Monkiedje  Pierre Servais  Mohamed Messouli  Claude Boutin 《Water, air, and soil pollution》2006,171(1-4):253-271

Groundwater protection from pollutants depends mostly on retention potentials of soil above groundwater table. Soil separating soil surface from groundwater table is made up of several layers and can be divided into different columns along its vertical transect. Wastewater percolation tests were carried out through one soil column CA, in contact with soil surface and through another CB, closely above groundwater table. The aim of the study was to assess the importance of soil columns CA and CB, in total coliforms and staphylococci retention during wastewater infiltration or groundwater recharge, in equatorial soils in Central African region. The results showed that, the fraction of total coliforms retained through soil column CA varied with respect to wastewater loads applied on top of soil column, from 69.22% to 99.95%, relative to the total coliforms concentration deposited on top. The fraction of total coliforms retained through CB varied with respect to wastewater loads applied, from 96.98 to 99.89% relative to the total coliforms deposited on top. Through both soil columns, fractions of staphylococci retained was in the order of 99.99% relative to the total staphylococci concentration deposited on top. For the whole bacteriological analysis, the fractions of total coliforms retained seems to be greater through deeper soil column than that of upper soil column. The bacterial contaminants retained relative to their concentrations in wastewater poured on soil column surfaces, varied from 6.17 log units to 9.73 log units. An applied load of 100 ml seemed to lead to the bacterial pollutants transported through both soil columns studied. NH₄ ⁺ was retained by fractions varying from 97.37 to 98.74%. Concentrations of various contaminants found in groundwater would be a tiny part, relative to quantities deposited on soil surface. Bacterial retention potentials of soil column separating soil surface from groundwater table during wastewater percolation, varies along its transect. It would be due to numerous and variable physical, chemical and structural properties of soil layers and bacteria on the one hand, and to results of various interactions between soil layer particles and cell bacteria, on the other hand.  相似文献   

Rubidium-Verarmung des wurzelnahen Bodens durch Maispflanzen     

N. Claassen  L. Hendriks  A. Jungk 《植物养料与土壤学杂志》1981,144(6):533-545

Rubidium depletion of the soil-root interface by maize plants Maize plants were grown in flat containers with radioactive labelled rubidium. Changes of the Rb concentration in soil in the vicinity of the roots were determined by means of the film density of autoradiographs. Results were as follows: The Rb concentration of the soil at the root surface decreased markedly within one day; only small changes occured after this period. Initially, the width of the depletion zone was very small. It extended in the following days in a radial direction. Therefore, after the initial phase the Rb supply of the plants depended on transport from more remote parts of the soil. Soil texture and Rb level strongly influenced both degree and distance of Rb depletion. Thus, the Rb concentration at the root surface decreased by 80% of the initial value in a sandy soil (4% clay) and by only 30% in a silt loam soil (loess, 21% clay). The depletion zone extended to a distance of 2 mm in the silt loam soil from the surface of the root cylinder and to 5 mm in the sandy soil. Hence, in the silt loam about 20% and in the sandy soil almost 100% of the total soil volume contributed Rb to the plant, assuming a root density of 1 cm per cm³ of soil. Increased levels of Rb enhanced Rb availability by increasing both the degree of soil depletion near the root surface and the size of the depletion zone. The quantity of Rb available per cm of root varied between 0.05 μmol in the silt loam with low Rb application and 2.7 μmol in the sandy soil with high Rb application. The amount of Rb depleted from the soil, expressed as per cent of the Rb exchangeable by ammoniumacetate ranged from 3 to 7% in the silt loam and from 20 to 30% in the sandy soil, calculated on the basis of 1 cm root per cm³ of soil. The Rb concentration of the soil solution near the root surface was reduced to 2 μmolar.  相似文献   

Pflanzenverfügbarkeit der Phosphatvorräte ackerbaulich genutzter Böden. -Langfristige Feldversuche zur Nutzbarkeit des Bodenphosphors und zur Bewertung der Bodenuntersuchung -     

Albrecht Jungk  Norbert Claassen  Volker Schulz  Joachim Wendt 《植物养料与土壤学杂志》1993,156(5):397-406

Availability of Phosphate Reserves in Arable Soils - Long Term Field Experiments for Assessing Soil P Reserves and Critical Soil Test Values - The objective of this work is to quantify the plant availability of soil P reserves accumulated by former fertilizer applications, the possibility of utilizing them by arable field crops and to determine critical soil test values. For this purpose several long term field experiments with large plots without replicates were initiated in 1977 on luvisols from loess (pH 6.8 – 7.4) in Lower Saxony with a sugar beet - winter wheat - winter barley/winter wheat crop rotation. Annual P applications were 0, 45, 90, 135 and 180 kg P₂O₅/ha as triple phosphate. Application of other fertilizers and plot management were according to farmer's practice. Despite of high yield levels phosphate response of plants was only 2 % at its maximum in the average of all crops in 15 years. This was confirmed by small plot experiments with four replicates placed into the large plots after 9 years, when soil P levels had been differentiated under the influence of plant P removal and P application. Herewith in agreement, shoot P concentration was found within the range generally regarded sufficient. It is therefore concluded that plant P demand has been fully satisfied by soil P reserves. Soil P test values, monitored by the P(H₂O) method of Sissingh, decreased markedly in 15 years, when no P was applied, they remained approximately constant when P application was equal to P removal and they increased when P addition was higher than P removal. Plants on a site with 4 mg P(H₂O)/L initially had severe P deficiency. Maximum yield was obtained when the soil P level was raised to 11 mg P(H₂O)/L. It is concluded that P reserves, which are often high in German arable soils, can be utilized by field crops and thus be lowered to about 10 mg P(H₂O)/L by reducing or omitting P dressings. For practical purposes it is suggested to restrict P application, if necessary at all, to the sugar beet crop in the rotation because they often respond more than small grain.  相似文献   

Arsenic speciation in farmed Hungarian freshwater fish   总被引：2，自引：0，他引：2  

Soeroes C  Goessler W  Francesconi KA  Kienzl N  Schaeffer R  Fodor P  Kuehnelt D 《Journal of agricultural and food chemistry》2005,53(23):9238-9243

Arsenic speciation analysis was carried out on freshwater farmed fish collected from an area with elevated groundwater arsenic concentrations in Hungary as well as from outside of the area (control samples). The arsenic species were determined by high-performance liquid chromatography-inductively coupled plasma mass spectrometry on methanol extracts of the muscle tissue from the fish. Catfish (Claries gariepinus) were raised in geothermal water where the average total arsenic concentrations were 167 (contaminated sites) and 15.1 ng As mL(-1) (control); they were all fed an artificial diet containing 2880 microg As kg(-1) total arsenic, mostly present as arsenobetaine. In the catfish, the accumulated total arsenic (2510-4720 microg As kg(-1)) was found mostly in the form of arsenobetaine suggesting that uptake of arsenic was dominated by their diet. Carp (Cyprinus carpio) were cultured in surface lakes with no significant arsenic pollution and had total arsenic concentrations ranging from 62 to 363 microg As kg(-1). The arsenic species found in the carp extracts differed markedly from those in the catfish in that no arsenobetaine was detected. Most samples of carp from the investigated sites contained low concentrations of As(III) (arsenite), As(V) (arsenate), MA (methylarsonate), and DMA (dimethylarsinate), and no other compounds were detected. The four individuals from the control site, however, all contained appreciable levels of oxo-arsenosugar-glycerol and oxo-arsenosugar-phosphate. Indeed, the oxo-arsenosugar-phosphate dominated the speciation pattern for these carp contributing about 75% of the sum of species. The contrast between these two freshwater aquaculture species regarding total arsenic and arsenic species has relevant toxicological aspects in terms of food safety.  相似文献   

Biscuit-making quality of backcross derivatives of wheat differing in kernel hardness     

M.T. Labuschagne  A. Claassen  C.S. van Deventer 《Euphytica》1997,96(2):263-266

Kernel texture in wheat has been found to be directly controlled by one or two major genes. Generally, good biscuit-making wheats are those with soft endosperm texture, lower protein content, more breakflour and a smaller particle size. The aim of this study was to determine the effect of the dominant soft endosperm genes on biscuit-making quality. Backcross derivatives were developed with a backcrossing procedure. The backcross derivatives and parents were planted in a randomised block design with six replications. Fourteen quality characteristics were measured. Except for hectolitremass and mixing time, the presence of the soft endosperm genes had a major effect on all characteristics used to predict biscuit-making quality. In the soft backcross derivatives there was a significant decrease in alkaline water retention capacity (AWRC), alveograph stability, alveograph strength, alveograph P/L ratio, flour extraction, and protein content. There was a significant increase in alveograph extensibility, biscuit diameter and breakflour yield. In this study, the presence of the soft endosperm genes was associated with good biscuit-making quality characteristics. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Manganese uptake and Mn efficiency of wheat cultivars are related to Mn‐uptake kinetics and root growth     

Upkar Singh Sadana  Parmodh Sharma  Nelson Castaeda Ortiz  Debasmita Samal  Norbert Claassen 《植物养料与土壤学杂志》2005,168(4):581-589

Wheat cultivars differ widely in manganese (Mn) efficiency. To investigate the reasons for different Mn efficiencies, a pot experiment with soil, a solution‐culture experiment, and model calculations were carried out. The pot experiment was conducted with wheat (Triticum aestivum L. cvs. PBW 373, PBW 154, PBW 343, PBW 138, and Triticum durum L. cvs. PBW 34 and PDW 233) grown in a screen house in India. The soil was a loamy sand with pH 8.1, DTPA‐extractable Mn 1.62 mg (kg soil)^–1, and initial soil solution Mn concentration (C_Li) of 0.19 μM. When fertilized with 50 mg Mn (kg soil)^–1, C_Li increased to 0.32 μM. At C_Li 0.19 μM, wheat cv. PBW 373 produced 74% of its maximum shoot dry weight (SDW) with 64% of its maximum root length (RL), while cv. PDW 233 produced only 25% of its maximum SDW with 11% of its maximum RL. The other wheat cultivars were between these extremes. Manganese deficiency caused a reduction in shoot growth, but more strongly reduced root growth. The low Mn efficiency of T. durum cv. PDW 233 was related to a strong depression of its root growth. Manganese influx was similar for all cultivars. In solution culture below 1 μM Mn, under controlled climate‐chamber conditions, Mn influx was linearly related to Mn concentration. Both the efficient cv. PBW 343 and the inefficient cv. PDW 233 had a similar influx. Uptake kinetic parameters from the solution experiment together with soil and plant parameters from the pot experiment were used in a mechanistic nutrient‐uptake model. Calculated values of Mn influx for wheat grown in soil were 55% to 74% of measured values. A sensitivity analysis showed that increasing C_Li or the slope of the uptake isotherm by about 30% would be enough to reach the observed influx. The results of this research indicate that an increase of Mn solubility by microbial or chemical mobilization would increase Mn uptake. But on the other hand, no chemical mobilization would be required to increase Mn uptake if the plant improved its uptake kinetics. Low Mn efficiency of some wheat cultivars was related to their reduced root growth at low soil Mn supply.  相似文献   

Evolution of clinical, haematological and biochemical findings in young dogs naturally infected by vector-borne pathogens     

de Caprariis D  Dantas-Torres F  Capelli G  Mencke N  Stanneck D  Breitschwerdt EB  Otranto D 《Veterinary microbiology》2011,149(1-2):206-212

Longitudinal studies evaluating the evolution of clinical, haematological, biochemical findings in young dogs exposed for the first time to multiple vector-borne pathogens have not been reported. With the objective of assessing the evolution of clinical, haematological and biochemical findings, these parameters were serially monitored in naturally infected dogs throughout a 1-year follow-up period. Young dogs, infected by vector-borne pathogens based on cytology or polymerase chain reaction, were examined clinically and blood samples were obtained at seven different follow-up time points. Dogs were randomized to group A (17 dogs treated with a spot-on formulation of imidacloprid 10% and permethrin 50%) or to group B (17 dogs untreated). In addition, 10 4-month-old beagles were enrolled in each group and used as sentinel dogs. At baseline, Anaplasma platys was the most frequently detected pathogen, followed by Babesia vogeli, Bartonella spp., Ehrlichia canis and Hepatozoon canis. Co-infections with A. platys and B. vogeli, followed by E. canis and B. vogeli, A. platys and H. canis and A. platys and Bartonella spp. were also diagnosed. In dogs from group B, abnormal clinical signs were recorded at different time points throughout the study. No abnormal clinical signs were recorded in group A dogs. Thrombocytopenia was the most frequent haematological alteration recorded in A. platys-infected dogs, B. vogeli-infected dogs and in dogs co-infected with A. platys and B. vogeli or A. platys and Bartonella spp. Lymphocytosis was frequently detected among dogs infected with B. vogeli or co-infected with A. platys and B. vogeli. Beagles were often infected with a single pathogen rather than with multiple canine vector-borne pathogens. There was a significant association (p<0.01) between tick infestation and A. platys or B. vogeli, as single infections, and A. platys and B. vogeli or A. platys and Bartonella spp. co-infections. This study emphasizes the clinical difficulties associated with assigning a specific clinical sign or haematological abnormality to a particular canine vector-borne disease.  相似文献   

Insights into the dynamics of endemic Coxiella burnetii infection in cattle by application of phase-specific ELISAs in an infected dairy herd     

Böttcher J  Vossen A  Janowetz B  Alex M  Gangl A  Randt A  Meier N 《Veterinary microbiology》2011,151(3-4):291-300

Serological diagnosis of acute and chronic Q fever in humans relies on detection of antibodies to phase I (PhI) and II (PhII) antigens of Coxiella (C.) burnetii. Although phase-specific antigens are available, they are not yet used in ruminants as they are in humans. This study focuses on phase-specific serology as a tool for analysis of the dynamics of infection in cattle. As a prerequisite, sero-prevalence in Bavarian cattle (1) and sero-prevalences for age-groups (2) were determined by ELISA (CHEKIT Q-Fever; mix of PhI/PhII-antigen). Subsequently, phase-specific antigens were coated onto ELISA plates individually and tests were simultaneously applied in an endemically infected herd with about 90 dairy cows and 250 calves/heifers in April 2005, March 2006 and retrospectively in May and October 2004. From April 2005 onward, placentas were analysed for C. burnetii by PCR (3). (1) Sero- and herd prevalences based on 21,051 sera from 603 Bavarian dairy farms collected in 2003 were 14.8% ± 0.48% and 72.3% ± 3.6%, respectively. (2) Analysis of 3965 animals from 105 farms for which age was reported revealed a base level of sero-prevalence of less than 5% in 1-2 years old animals, it increased to 15% in 2-3 years old and reached a plateau (25-30%) in cows four years and older. (3) In May 2004 and April 2005 a peak of PhI(-)/PhII(+)-prevalence in primiparous cows (2.0-3.5 years) was observed; but not in October 2004 and March 2006. The PhI(-)/PhII(+)-pattern in primiparous cows changed to negative (one-third), PhI(+)/PhII(+) (1/3) or persisted (1/3). In contrast, sero-conversion was rare in multiparous cows (>3.5 years). If the PhI(-)/PhII(+) pattern was detected, it was due to an infection in preceding years. This pattern persisted (2/3) or changed to negative (1/3); a change to PhI(+)/PhII(+) did not occur. PhI(-)/PhII(+) in heifers (1-2 years) always changed to negative. Detection of PhII-antibodies was significantly associated with PCR-positive placentas. Remarkably, 45% of sera with the PhI(-)/PhII(+) pattern were negative for the CHEKIT Q-Fever ELISA, thus this test missed an important group of infected animals.  相似文献   

Furan formation from lipids in starch-based model systems, as influenced by interactions with antioxidants and proteins     

Owczarek-Fendor A  De Meulenaer B  Scholl G  Adams A  Van Lancker F  Eppe G  De Pauw E  Scippo ML  De Kimpe N 《Journal of agricultural and food chemistry》2011,59(6):2368-2376

The formation of furan upon sterilization of a lipid-containing starch gel was investigated in the presence of various antioxidants, namely, α-tocopherol, β-carotene, and ascorbic acid, with and without proteins. Results indicated that α-tocopherol did not significantly influence furan formation from oxidized lipids. β-Carotene, suggested previously to be a furan precursor itself, did influence the generation of furan in a concentration-dependent manner, although to a limited extent. Surprisingly, the presence of lipids seemed to limit the furan generation from β-carotene. Interestingly, the addition of ascorbic acid to the emulsions containing soybean or sunflower oils considerably enhanced the formation of furan from these oils. This was also the case when fresh oils were applied, shown previously to be nearly unable to generate furan. This observation can be explained by an intensified ascorbic acid degradation stimulated by the presence of lipids.  相似文献