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Endothelial cells in blood vessels are known to be important during the later stages of organ development in the embryo. However, their involvement at the induction stage of organ formation has not been previously documented. As Bahary and Zon explain in their Perspective, new work demonstrates that endothelial cells secrete factors early in development that induce embryonic endoderm to become liver or pancreas (Matsumoto et al., Lammert et al.). 相似文献
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Treatment of sunflower seeds with benomyl, vinclozolin, iprodione or procymidone virtually eliminated seed-borne Sclerotinia sclerotiorum. Applications of fungicides increased the number of surviving seedlings when seeds were sown in vermiculite or in steam-sterilized soil. With the exception of benomyl, fungicides were significantly more effective when applied in acetone solutions than when 100 g a.i./100 kg of seed was applied as conventional dry dressings. There was no difference in effectiveness between the two application methods when the dry dressings were applied at 200 g a.i/100 kg of seed. The acetone infusion method had no deleterious effects on germination of disease-free seed nor on seedling vigour. For a comparable level of control, less fungicide was needed in the infusion treatment than in the dust treatment. If fungicidal treatment of sunflower seeds is used routinely then the introduction of S. sclerotiorum into uninfested land could be controlled. 相似文献
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Helmuth L 《Science (New York, N.Y.)》2000,289(5482):1123-1125
The secret of the success of Mycobacterium tuberculosis, the pathogen that causes tuberculosis, is that it can linger undetected in the lungs for decades, hiding from the immune system's macrophages that aim to chew it up and spit it out. Now a team of researchers has uncovered a vulnerability in this resilient bug that suggests new ways to starve it out of its bolt-hole. 相似文献