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921.
《Neuron》2021,109(24):4094-4108.e5
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922.
Mouse embryos of the NMRI strain between the 7th and 9th day of gestation were isolated from the uterus and dissected into the various tissue derivatives in order to investigate newly synthesized proteins during morphogenesis. The day 7 embryo was fragmented into trophoblast and ectoplacental cone, distal and proximal endoderm, extraembryonic and embryonic ectoderm. The day 8 and day 9 embryos were divided into trophoblast and placental anlage, yolk sac, amnion, and allantois, as well as cranial, central, and caudal embryonic tissue. The intact embryos were incubated in Dulbecco's minimum essential medium in the presence of 35S-methionine for 4 h, then dissected into the various fragments, and further processed for two-dimensional gel electrophoresis. Protein synthesis of the isolated tissue derivatives was analyzed and compared for the three developmental stages. Concerning the proteins with isoelectric points in the range of 4.5 to 8.0 and molecular weight ratio (M(r)) values between 20,000 and 200,000, we found several significant quantitative and qualitative differences in the various tissue fragments. In addition, we observed further quantitative and qualitative differences in protein synthesis during the postimplantation period investigated. We propose that the differences reflect some of the cell lineage- and developmental stage-specific changes in gene expression during early mammalian differentiation.  相似文献   
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We investigated spatial patterns of evolutionary diversity along Neotropical Non-Flooded Evergreen Forests (NEF). We addressed the following questions: (i) What are the main NEF evolutionary groups? (ii) How evolutionary diversity varies across NEF environmental gradients? Based on a phylogeny of 1248 tree genera distributed over 1824 NEF assemblages, we examined the evolutionary differentiation using UPGMA and evopca. We measured lineage diversity (ses.PD) and structure (ses.MPD and ses.MNTD) and tested their response to environmental gradients using linear models. Phylogenetic dissimilarity segregated NEF into 12 evolutionary groups that largely confirm groups obtained in our previous work based on floristic similarity. However, one discrepancy was the amalgamation of Amazon and northern Atlantic Forest assemblages, while the southern Atlantic Forest remained an isolated group. Furthermore, Mesoamerica, which had been recognized as a single group, here split into six evolutionary groups. We found greater lineage diversity as altitude and latitude increased and temperature decreased. Evolutionary groups with the highest mean values of lineage diversity were those composed of Mesoamerican cloud forests, which harbor a mixture of tropical and temperate lineages representing a confluence of South and North American floras. We found that variations in phylogenetic diversity in NEF are primarily related to the coexistence of lineages of temperate and tropical climates in the mountain and nebular environments of NEF, indicating the strong contribution of extratropical niche conservatism in structuring evolutionary diversity.  相似文献   
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《Cell reports》2023,42(4):112325
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