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Journal of Plant Diseases and Protection - A broad range of different Fusarium (F.) species is associated with Fusarium head blight (FHB) on barley and the corresponding negative effects in... 相似文献
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The development of proteolytic enzymes (trypsin, chymotrypsin and aminopeptidase) was studied in three species of fish: Coregonus sp. (hybrids of C. wartmanni and C. lavaretus from Lake Constance), Salmo gairdneri and Rutilus rutilus. Enzyme activity increased more or less with increasing age, particularly in R. rutilus. In this species (a stomachless cyprinid), the level of proteolytic activity was considerably higher than that of S. gairdneri and Coregonus. However, in trout, the low activity of pancreatic enzymes may be compensated by the action of the stomach whereas in coregonids the stomach is not developed until 50 days (body weight without gut content: 65 mg; temperature: 10°C) after hatching. In coregonids this may lead to insufficient digestion of proteins which nevertheless can be compensated by the use of exogenous (dietary) enzymes ingested together with the natural diet. In coregonid larvae fed with Moina sp., exogenous trypsin represents a very high portion of the total tryptic activity. In juveniles older than 60 days (> 150 mg) and in the other two species, the exogenous portion of tryptic activity is less important. Furthermore, a change in the pattern of tryptic isozymes has been found during development of coregonids. It is concluded that low enzyme production as well as the absence of a stomach in the first few weeks after hatching are two important reasons for difficulties in rearing coregonids on an artificial diet. 相似文献
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The similarity in gene order between closely related taxa suggests that genomic information from model systems should facilitate gene isolation characterization in target crops. …… 《分子植物育种》2007,5(2):152-153
The similarity in gene order between closely related taxa suggests that genomic information from model systems should facilitate gene isolation and characterization in target crops. If this is the case, a great deal of effort and investment can be saved by focusing attention on a few model systems that have appropriate applicability. Pea (Pisura sativum) provides a good test case: its genome is large and the insertion sites for repetitive elements, which comprise the bulk of its genome, are highly polymorphic (Jing et al., 2005; Vershinin et al., 2003), so we expect a great deal of structural polymorphism between the genomes of Pisum lines. Yet the genetic map of Pisum is essentially coUinear with Medicago (Choi et al., 2004; Kalo et al., 2004). 相似文献
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Rudolf Hofer Reinhard Lackner Joachim Kargl Bertha Thaler Danilo Tait Leopoldo Bonetti Raffaele Vistocco Giovanna Flaim 《Water, air, and soil pollution》2001,125(1):189-200
Southern populations of the European minnow fromremote oligotrophic mountain lakes along an Alpinenorth-south transect accumulated more p,p DDE andPCBs than northern populations. As these semi-volatileorganochlorines predominantly evaporate in warmcountries, higher rates of condensation (deposition)are assumed to occur in the southern slopes of theAlps. The higher accumulation of lead and cadmium insouthern population is rather attributed to geogenicand specific environmental impacts than to atmosphericdeposition. Increasing liver ratios of [glutathionedisulfide]/[glutathione], a potential indicator foroxidative stress, from north to south reflect thegenerally higher toxic load at remote sites at thesouthern edge of the Alps. However, histopathologicalchanges in the liver did not correlate withaccumulated toxicants indicating that deposition doesnot lead to severe lesions but induces specificmechanisms for detoxification. 相似文献
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Initial results from the Seasat scanning multichannel microwave radiometer indicate that the sea surface temperature can be measured with a root-mean-square sensitivity of 1.2 degrees C or better. The first microwave map of sea surface temperature for the entire Pacific has been produced. 相似文献
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Cardiac rate regulated by nutritional factor in young rats 总被引:1,自引:0,他引:1
M A Hofer 《Science (New York, N.Y.)》1971,172(987):1039-1041
Milk fed by stomach tube to 2-week-old rats separated from their mothers without feeding for 16 hours transiently but fully reversed the decrease in cardiac rate which had occurred during separation. This effect was rapid in onset and was related to dosage; it was not dependent upon gastric distention, but did depend upon beta-adrenergic transmission. 相似文献
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Feeding deterrence and contact toxicity of Stemona alkaloids-a source of potent natural insecticides 总被引:1,自引:0,他引:1
Brem B Seger C Pacher T Hofer O Vajrodaya S Greger H 《Journal of agricultural and food chemistry》2002,50(22):6383-6388
On the basis of chronic feeding bioassays with neonate larvae of Spodoptera littoralis reared on an artificial diet, the methanolic leaf and root extracts from Stemona collinsae displayed very high insect toxicity compared to those of two Aglaia species, a commercial Pyrethrum extract, and azadirachtin, whereas S. tuberosa extracts demonstrated low activity in roots and no activity in leaves. Beyond that, in leaf disk choice tests against fifth instar larvae, S. collinsae showed strong antifeedant activity, whereas S. tuberosa was characterized by remarkable repellency. The anti-insect properties of both species were based on pyrrolo[1,2-a]azepine alkaloids, from which didehydrostemofoline (asparagamine A) was the major compound of the roots of S. collinsae, exhibiting the highest toxicity in feeding assays. Saturation and hydroxylation of the side chain in the co-occurring stemofoline and 2'-hydroxystemofoline, respectively, led to an increasing loss of activity. Contact toxicity tests with stemofoline and didehydrostemofoline exhibited even higher activities than those of Pyrethrum extract. Tuberostemonine was the dominating alkaloid in the roots of S. tuberosa, showing outstanding repellency but no toxic effects. 相似文献