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The diploid anuran Xenopus tropicalis has emerged as a key research model in cell and developmental biology. To enhance the usefulness of this species, we developed methods for generating immortal cell lines from Nigerian strain (NXR_1018, RRID:SCR_013731) X. tropicalis embryos. We generated 14 cell lines that were propagated for several months. We selected four morphologically distinct lines, XTN-6, XTN-8, XTN-10 and XTN-12 for further characterization. Karyotype analysis revealed that three of the lines, XTN-8, XTN-10 and XTN-12 were primarily diploid. XTN-6 cultures showed a consistent mixed population of diploid cells, cells with chromosome 8 trisomy, and cells containing a tetraploid content of chromosomes. The lines were propagated using conventional culture methods as adherent cultures at 30°C in a simple, diluted L-15 medium containing fetal bovine serum without use of a high CO 2 incubator. Transcriptome analysis indicated that the four lines were distinct lineages. These methods will be useful in the generation of cell lines from normal and mutant strains of X. tropicalis as well as other species of Xenopus . 

Although the microcrustaceanDaphniais becoming an organism of choice for proteomic studies, protein expression across its life cycle have not been fully characterized. Proteomes of adult females, juveniles, asexually produced embryos, and the ephippia‐resting stages containing sexually produced diapausing freezing‐ and desiccation‐resistant embryos are analyzed. Overall, proteins with known molecular functions are more likely to be detected than proteins with no detectable orthology. Similarly, proteins with stronger gene model support in two independent genome assemblies can be detected, than those without such support. This suggests that the proteomics pipeline can be applied to verify hypothesized proteins, even given questionable reference gene models. In particular, upregulation of vitellogenins and downregulation of actins and myosins in embryos of both types, relative to juveniles and adults, and overrepresentation of cell‐cycle related proteins in the developing embryos, relative to diapausing embryos and adults, are observed. Upregulation of small heat‐shock proteins and peroxidases, as well as overrepresentation of stress‐response proteins in the ephippium relative to the asexually produced non‐diapausing embryos, is found. The ephippium also shows upregulation of three trehalose‐synthesis proteins and downregulation of a trehalose hydrolase, consistent with the role of trehalose in protection against freezing and desiccation.