Citation: Erkenbrack, E. M. (2017). Divergence of ectodermal and mesodermal gene regulatory network linkages in early development of sea urchins. Proceedings of the National Academy of Sciences, 113(46), E7202-E7211.
A Conserved Role for VEGF Signaling in Specification of Homologous Mesenchymal Cell Types Positioned at Spatially Distinct Developmental Addresses in Early Development of Sea Urchins
Comparative studies of early development in echinoderms are revealing the tempo and mode of alterations to developmental gene regulatory networks and to the cell types they specify. In euechinoid sea urchins, skeletogenic mesenchyme (SM) ingresses prior to gastrulation at the vegetal pole and aligns into a ring-like array with two bilateral pockets of cells, the sites where spiculogenesis will later occur. In cidaroid sea urchins, the anciently diverged sister clade to euechinoid sea urchins, a homologous SM cell type ingresses later in development, after gastrulation has commenced, and consequently at a distinct developmental address. Thus, a heterochronic shift of ingression of the SM cell type occurred in one of the echinoid lineages. In euechinoids, speci cation and migration of SM are facilitated by vascular endothelial growth factor (VEGF) signaling. We describe spatiotemporal expression of vegf and vegfr and experimental manipulations target- ing VEGF signaling in the cidaroid Eucidaris tribuloides.
Production of fungal and bacterial growth modulating secondary metabolites is widespread among mycorrhiza-associated streptomycetes
Studies on mycorrhiza associated bacteria suggest that bacterial-fungal interactions play important roles during mycorrhiza formation and affect plant health. We surveyed Streptomyces Actinobacteria, known as antibiotic producers and antagonists of fungi, from Norway spruce mycorrhizas with predominantlyPiloderma species as the fungal partner. Mycorrhiza associated streptomycetes appear to have an important role in inhibiting the growth of fungi and bacteria. Additionally, our study indicates that the Streptomyces strains, which are not general antagonists of fungi, may produce still un-described metabolites.
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