Leistungsprüsung und Rationalisierung     

Dr. e. h. W. Hohenadl 《European Journal of Forest Research》1940,62(1):1-9

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The culturable leaf mycobiome of Viscum album subsp. austriacum     

Robert Jankowiak  Piotr Bilański  Julita Zając  Adrianna Jobczyk  Stephen J. Taerum 《Forest Pathology》2023,53(4):e12821

In Poland's pine forests, mistletoe (Viscum album subsp. austriacum) abundance has increased over the past 20 years. This mistletoe infestation has decreased the growth and vigour of Scots pine trees. In this study, we surveyed the culturable fungi from healthy and diseased V. album subsp. austriacum leaves from two stands in Poland. In total, 63 distinct species were identified, 99.8% of which belonged to the phylum Ascomycota. The community compositions of fungi in mistletoe leaves were similar in healthy and diseased leaves as Alternaria alternata, Aureobasidium pullulans, Botryosphaeria visci, Fusarium paeoniae and Microsphaeropsis olivacea were consistently found in leaves of all symptom types. The most frequently isolated fungus from asymptomatic leaves was M. olivacea, followed by A. alternata, A. pullulans and Hypoxylon rubiginosum. In comparison, the most frequently isolated fungi from leaves with rusty-brown necrotic spots were (in decreasing order) M. olivacea, B. visci, F. paeoniae and A. alternata, while the most frequently isolated fungi from leaves with black or dark brown spots were M. olivacea, A. alternata, A. pullulans, Epicoccum layuense and F. paeoniae. This study was the first comprehensive report showing that certain fungal species may be pathogens of V. album subsp. austriacum in Poland. This study was also the first report of F. paeoniae, F. juglandicola, Diaporthe vacuae and Heterotruncatella spartii from V. album, and the first report of D. vacuae and H. spartii in Poland.  相似文献   

Natural products as pesticides: Two examples of stereoselective synthesis     

Thomas Früh  Philippe Chemla  Jürg Ehrler  Saleem Farooq 《Pest management science》1996,46(1):37-47

The strategy and synthetic efforts leading to efficient stereoselective syntheses of thiangazole, a tris-thiazolinyl-oxazole metabolite isolated from Polyangium spp., and of hydantocidin, a spironucleoside metabolite isolated from Streptomyces hygroscopicus, are discussed.  相似文献   

High-throughput screening reveals small molecule modulators inhibitory to Acidovorax citrulli     

Yu Lu  Loïc Deblais  Gireesh Rajashekara  Sally A. Miller  Yorsa A. Helmy  Haijun Zhang  Ping Wu  Yanhong Qiu  Xiulan Xu 《Plant pathology》2020,69(5):818-826

Acidovorax citrulli is a seed-transmitted gram-negative bacterium that can cause substantial economic yield loss in watermelon and melon production worldwide. Four small-molecule libraries containing 4,952 compounds were selected for high-throughput screening against A. citrulli wild-type strain Xu3-14 by evaluation of growth inhibition. One hundred and twenty-seven molecules (2.5% hit rate) were identified as bactericidal or bacteriostatic against A. citrulli at 100 μM. Secondary screens indicated that 27 candidate compounds were more effective against A. citrulli Group II strains than Group I strains (classified using repetitive element PCR). Several compounds were inhibitory to other pathogenic bacteria, including Clavibacter michiganensis subsp. michiganensis and Xanthomonas campestris pv. campestris, but did not affect the growth of plant beneficial bacteria Pseudomonas fluorescens and Bacillus subtilis. More than half of the compounds did not inhibit germination of Arabidopsis or watermelon seeds. The effect of small molecules on A. citrulli seed-to-seedling transmission was evaluated by applying each compound to inoculated watermelon seeds and assessing seedling infection. Nine compounds were chosen for further investigation based on their reduction of percentage seedling infection and compiling scores on their specificity, sensitivity, and phytotoxicity obtained in the secondary screens. The five best compounds were selected (thiamphenicol, nadifloxacin, pipemidic acid, ciclopirox, and zinc pyrithione) for greenhouse tests and were found to effectively reduce the seed-to-seedling transmission of A. citrulli in both artificially and naturally infested seeds. These top five compounds provide a basis for future development of an A. citrulli-specific bactericide.  相似文献   

Proteolytic digestive enzymes of carnivorous (Silurus glanis L.), herbivorous (Hypophthalmichthys molitrix Val.) and omnivorous (Cyprinus carpio L.) fishes     

Erzsbet Jns  Mria Rgyanszki  Jnos Olh  Lszl Boross 《Aquaculture (Amsterdam, Netherlands)》1983,30(1-4):145-154

The authors studied the pH, temperature dependence, heat inactivation and the reactive groups of the active centers of proteolytic enzymes extracted from the alimentary canal of silver carp, common carp and sheatfish. In these three fish species activation energy values of enzymes, active in a pH range near neutral (7.5) were nearly identical, i.e.: silver carp: 14 kcal/mol; common carp: 15.4 kcal/mol; sheatfish: 15.7 kcal/mol. Differences were found in heat stability. At 55°C time values for 50% activity loss were 3.8: 1.3 and 14.6 min in the case of silver carp, common carp and sheatfish, respectively. Activities of enzymes, active in a pH range near neutral were inhibited by 82–94% by 10⁻³M PMSF, and by 2–5% by 10⁻³M EDTA. Proteolytic enzymes of the three fish species proved not to be homogeneous, but the largest part consisted of seryl-proteinases.  相似文献   

The effects of less-expensive plant protein sources replaced with soybean meal in the juvenile diet of grass carp (Ctenopharyngodon idella): growth, nutrient utilization and body composition     

Kenan K?prücü  Ebru Sertel 《Aquaculture International》2012,20(3):399-412

In this study, the effects of less-expensive protein sources replaced with soybean meal on growth performance, nutrient utilization and body composition of juvenile grass carp were investigated. For this purpose, a control diet containing 42% soybean meal was prepared. Cotton seed meal (CSM), sunflower meal (SFM) and corn meal (CM) were added to the experimental diets by replacing 100% of the soybean meal protein used in the control diet. All diets were iso-nitrogenous (40% crude protein) and iso-caloric (19.5?MJ?kg^?1 gross energy). Each treatment had three replicates, and 20 juvenile grass carps (3.5?±?0.1?g, initial weight) were located in per replicate. The fish were fed to satiety three times in a day during 3?months at 26°C of water temperature in glass aquarium (45 l). The results of the study showed that the weight gain (308.6?C448.6%), specific growth rate (1.56?C1.89%/day), feed conversion rate (1.2?C1.9), protein efficiency ratio (1.32?C2.08), and apparent digestibility coefficients of protein (80.5?C89%) or sum of amino acids (80.5?C88.9%) were not significantly affected by the experimental diets, except diet CM. All of these values obtained for the diet CM were significantly lower than those of fish fed on the control, CSM and SFM diets. However, there were no significant differences between the lipid digestibility of the diets, and crude protein, lipid, and gross energy contents in the whole body of fish in experiments. In conclusion, CSM and SFM diets were highly utilized by juvenile grass carp, but not CM diet. These results combined with the remarkable acceptability of diets containing high levels of plant protein ingredients with identical growth performances of juvenile grass carp show clearly that dietary soybean meal level can be considerably reduced without any adverse consequence in terms of somatic growth and nitrogen utilization.  相似文献   

精准喷雾控制装置的设计与制作     

宋淑然  王大飞  孙道宗  洪添胜  夏侯炳 《农机化研究》2010,32(5)

为了实现精准喷雾,设计并制作了一套基于51单片机的精准喷雾自动/手动两种模式切换的控制装置。在自动模式下,单片机根据现场信号输入模块提供的作物病虫害情况分别打开或关闭对应的电磁阀;手动模式下,由面板手动开关分别控制各个电磁阀打开或关闭。经田间试验测定,该喷雾控制装置能够在自动或手动模式下实现精准喷雾作业控制。  相似文献   

Lebenszähheit eines Rehboks     

E. v. c. 《European Journal of Forest Research》1868,12(1):303-303

Ohne Zusammenfassung  相似文献   

啮小蜂视觉和触角在交配中的作用观察   总被引：2，自引：2，他引：2  

陆剑锋邱鸿贵  邱中良沈伯钧 符文俊 《昆虫天敌》2005,27(1):15-20

本文研究了啮小蜂Tetrasichus,sp．视觉和触角在交配中的作用，实验结果表明，视觉对雄蜂起重要作用，对雌蜂作用则不显著；触角在啮小蜂求偶识别和接受中起重要的作用，雄蜂柄节具有一分泌小孔，求偶的雄蜂遇到雌蜂后柄节能分泌大量的膏状渗出物，雌蜂是靠接触雄蜂触角来识别和接受雄蜂。  相似文献   

Pharmacokinetics of sulphadiazine-trimethoprim in lactating dairy cows     

Kaartinen L  Löhönen K  Wiese B  Franklin A  Pyörälä S 《Acta veterinaria Scandinavica》1999,40(3):271-278

Five Finnish Ayrshire cows in mid or end-lactation were treated with 40 mg sulphadiazine/kg and 8 mg trimethoprim/kg using intravenous (i.v.), intramuscular (i.m.) and subcutaneous (s.c.) routes. Elimination of sulphadiazine was not affected by the route of administration (median t1/2 4.4-5.0 h) while elimination of trimethoprim was strongly limited by slow absorption from the injection site after s.c. and i.m. administration (median for apparent t1/2 21-25 h) compared to that after i.v. administration (median t1/2 1.2 h; p < 0.05). The median bioavailability of trimethoprim was also decreased, being 37% and 55% after s.c. and i.m. administration, respectively. When i.v. administration was used, trimethoprim concentration exceeded 0.1 mg/l in milk between 0.15-8 h while sulphadiazine concentrations above 2 mg/l were maintained from 0.5-2 h to 8 h. After s.c. and i.m. administration sulphadiazine in milk behaved similar to that after i.v. administration, while trimethoprim time-concentration curves were flat and trimethoprim concentrations were around 0.1 mg/l for an extended period of time (8-12 h). Median Cmax values in milk were only 0.07 mg/l and 0.10 mg/l for s.c. and i.m. administrations, respectively. After s.c. administration, 4 out of 5 cows showed signs of pain. After i.m. administration, 2 of the cows showed clear signs of pain and one had some local tenderness at the site of injection.  相似文献