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991.
Ganodermadiol, lucidadiol and applanoxidic acid G were isolated as first triterpenes from the European Basidiomycete Ganoderma pfeifferi. The compounds show antiviral activity against influenza virus type A and HSV type 1.  相似文献   
992.
993.
A method is described for the electron capture gas-liquid chromatographic determination of thiabendazole and methyl 2-benzimidazole carbamate (MBC) after derivatization with pentafluorobenzyl bromide (PFB-Br). The samples are extracted with ethyl acetate, and the residual thiabendazole, benomyl, and MBC are isolated by liquid-liquid extraction into dilute HCl. After neutralization and re-extraction with ethyl acetate, thiabendazole and MBC are reacted with PFB-Br to form the PFB derivatives. Alumina column chromatography was used to clean up extracts, and the derivatives could be detected as low as 5-10 pg. Recoveries were 95-98% from fruits fortified with 0.3-2.0 ppm thiabenzadole; recoveries were 91-97% when 0.05-1.0 ppm benomyl/MBC were added to fruits/crops. The PFB derivatives were identified by gas-liquid chromatography-mass spectrometry.  相似文献   
994.
Seminal roots of wheat and barley seedlings were inoculated with G. graminis var tritici on regions 0, 5- and 15-days old, and assessed for intensity and extent of infection after standard times. Wheat roots were most heavily infected on young regions, whereas barley roots were most heavily infected on old ones. The effect of root age in wheat was similar in both unsterile and aseptic conditions, so it could not be ascribed to saprophytic rhizosphere micro-organisms interacting with G. graminis.The contrasting results for wheat and barley are explained by a single hypothesis, based on decreasing host-resistance in the root cortex but increasing resistance at or near the endodermis as the roots age. It is suggested that, under some conditions, even small amounts of non-pathogenic root cortex death can enhance infection by G. graiminis. This interpretation may explain several aspects of take-all and its biological control by other dark mycelial parasites.  相似文献   
995.
996.
997.
Isolates of the reported mycoparasites Pythium oligandrum, P. acanthicum and P. periplocum markedly reduced growth and cellulolysis by Botryotrichum piluliferum, grew rapidly across agar plates precolonized by Phialophora radicicola var radicicola (sensu Deacon) and, where tested (not P. periplocum), were non-pathogenic towards higher plants. Isolates of P. echinulatum, P. mamillatum. P. megalacanthum, P. spinosum, P. ultimum and one isolate of P. acanthicum behaved differently from the mycoparasites and could, themselves, be placed in two groupings in these tests. It is suggested that the ability or otherwise to grow on Phialophora-precolonized agar plates may help to distinguish broad biological groupings within the genus Pythium, but these groupings may cut across conventional taxonomic ones.One isolate of P. acanthicum was tested for its effects on a range of cellulolytic fungi: it reduced their growth to different extents, as did P. oligandrum.Plates of potato-dextrose agar precolonized by Phialophora radicicola were used to isolate selectively P. oligandrum and similar fungi from soils, but the use of hemp seed baits in conjunction with precolonized plates was less selective for these fungi.Straw pieces precolonized by P. oligandrum and buried in soil decomposed at the same rate as virgin straws or those precolonized by P. ultimum or Mucor hiemalis. Subsequently, Stachyholrys atra appeared to colonize straws more frequently from soil, and Fusarium spp. less so, in the presence of P. oligandrum than in its absence. In the laboratory, P. oligandrum was antagonized by Slachyholrys, whereas Fusarium spp. were frequently overgrown by the Pythium.  相似文献   
998.
An understanding of the relationship between gastrointestinal (GI) motility and disease is imperative for the proper treatment of large animal patients, especially as new therapeutic agents become available. However, the abundance of information that has become available in the last 2 decades makes gaining this understanding a formidable task. This article summarizes the changes in GI motility caused by some common diseases and conditions encountered in large animal practice, such as GI obstruction, postoperative ileus, resection and anastomosis, diarrhea, endotoxemia, GI parasitism, hypocalcemia, and pregnancy. J Vet Intern Med 1996;10:51–59. Copyright © 1996 by the American College of Veterinary Internal Medicine .  相似文献   
999.
Alferink  PP  Jansen 《中国奶牛》2001,(5):46-48
本文阐述的是使用喜利康犊牛奶粉的优势。1 成分与犊牛的需要表1反映了喜利康与鲜奶的成分差异。如今的鲜奶成分与犊牛的需要不一致,主要原因是当今的奶牛选育注重提高日后鲜奶中的脂肪与蛋白成分,现在鲜奶中脂肪与蛋白含量远比过去的要高,也远高于犊牛的生长需要。这样不仅会造成犊牛消化系统紊乱,而且,犊牛也并不能够很快地消化全部的脂肪与蛋白,不能消化的脂肪与蛋白则被肠道病菌利用。鲜奶中的脂肪与蛋白成分含量不稳定,而喜利康是稳定不变的,并且,喜利康中的蛋白与脂肪含量是针对犊牛的需要而配制的。另外,铁在鲜奶中的含量…  相似文献   
1000.
Factors likely to influence the uniformity of treatment and the stability of the insecticides incorporated into peat blocks were investigated. When an Adelphi horizontal mixer was used, 90% of the blocks contained the mean dose (±10%) after dry-mixing the diazinon granules for 3 min. Treatment was slightly less uniform using a concrete mixer or a spade. Between-block variability was greatest when diazinon was applied to the wet surfaces of prepared blocks; in this process, sprinkling granules by hand was less erratic than spraying a liquid formulation. When granular, wettable powder, or emulsifiable concentrate formulations of diazinon were incorporated using the Adelphi mixer, neither the between-block variability nor the subsequent stability of the insecticide were significantly influenced by the formulation used. Insecticide stability was studied by incorporating chlorfenvinphos, chlorpyrifos, diazinon and phorate at 10 mg a.i. per block in January, March, May and July. The relative order of persistence was chlorfenvinphosChlorpyrifos > phorate≫diazinon. There was little loss of insecticide ( < 10%) from the blocks treated with chlorfenvinphos or chlorpyrifos, and the stability of the insecticides was unaffected by seasonal temperature changes, but the rate of loss of diazinon increased markedly from January to July. The rate of oxidation of phorate to its sulphoxide and sulphone analogues increased gradually from January to May but was much slower than in the field after a bow-wave application. With all insecticides, there was no significant difference in loss rates at 25 and 10 mg a.i. per block. After incorporation into three moss peats and two proprietary blocking composts, there was no consistent difference in the rates of loss of either diazinon or of total phorate residues, although the rates of oxidation of phorate and its sulphoxide were not similar in all the peats and composts. It was concluded that, despite the substantial water content and high insecticide concentrations, the principal factor determining insecticide behaviour in the blocks was the adsorptive capacity of the peat.  相似文献   
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