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Human trophoblast survival at low oxygen concentrations requires metalloproteinase-mediated shedding of heparin-binding EGF-like growth factor 总被引:1,自引:0,他引:1
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The life cycle and developmental stages of Aylax hypecoi (Trotter, 1913, Hymenoptera: Cynipidae: Aylacini) were studied in detail. Aylax hypecoi is known to induce galls in fruits of two Hypecoum species — H. imberbe and H. geslini (Papaveraceae) and the larva develops in host plant fruits. The morphology and development of egg, larva and pupa were investigated, which
has previously not been done. The shape and size of terminal-instar larvae and associated galls are sex-specific. Overwintering
stage, adult emergence and flying periods, and egg productivity were studied also. 相似文献
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Anelia Iantcheva Mireille Chabaud Viviane Cosson Marielle Barascud Bernadette Schutz Catherine Primard-Brisset Patricia Durand David G. Barker Mariana Vlahova Pascal Ratet 《Plant cell reports》2009,28(10):1563-1572
Insertion mutant collections are powerful tools for genetic studies in plants. Although large-scale insertional mutagenesis
using T-DNA is not feasible in legumes, the Tnt1 tobacco retrotransposon can be used as a very efficient mutagen in the Medicago truncatula R108 genotype. In this article, we show that Tnt1 can also be exploited to create insertional mutants via transformation and/or regeneration in the reference cultivar Jemalong.
Tnt1 insertional mutagenesis in Jemalong following Agrobacterium tumefaciens-mediated transformation was found to be very efficient, with an average of greater than 15 insertions/line. In contrast,
regeneration using low-copy transgenic starter lines resulted in a highly variable rate of new Tnt1 insertions. With the goal of increasing the number of additional Tnt1 insertions during regeneration of starter lines, we have compared the insertion frequencies for a number of different regeneration
protocols. In addition, we have been able to show that sucrose-mediated osmotic shock preceding regeneration significantly
increases the transposition frequency. Under optimal conditions, 95% of the regenerated Jemalong plants possess new insertions. 相似文献
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Background
Ribose 2'-O-methylation, the most common nucleotide modification in mammalian rRNA, is directed by the C/D box small nucleolar RNAs (snoRNAs). Thus far, more than fifty putative human rRNA methylation guide snoRNAs have been identified. For nine of these snoRNAs, the respective ribose methylations in human 28S rRNA have been only presumptive. 相似文献47.