Tectonic control on the sedimentary record of the central Moldavidian Basin (Eastern Carpathians, Romania)

The sedimentary record of the Tarcău and Vrancea Nappes, belonging to the flysch accretionary zone of the Eastern Carpathians (Eastern Carpathian Outer Flysch), registered Cretaceous-Miocene events during the evolution of the Moldavidian Basin. Our biostratigraphic data indicate that the deposits studied are younger than previously reported. The comparison of sedimentary record studied with the Late Cretaceous-Early Miocene global eustatic curve indicates that eustatic factor played a secondary role, after the tectonic one. Four main stages of different processes influenced by tectonics are recognized in the sedimentary record: (1) Campanian-Maastrichtian-earliest Paleocene; (2) latest Ypresian-Lutetian; (3) late Chattian-earliest Aquitanian, and (4) late Aquitanian-early Burdigalian. The late Chattian- earliest Aquitanian and late Aquitanian-early Burdigalian records indicate a high tectonic influence. The first event was related to the foredeep stage of the sedimentary domain studied, and the second one to the deformation stage of the same domain. The sedimentary records of tectonic influence recognized during these stages are useful tools for geodynamic reconstructions. The stratigraphic correlation of Tarcău and Vrancea sedimentary records are used

PipX, the coactivator of NtcA, is a global regulator in cyanobacteria

To modulate the expression of genes involved in nitrogen assimilation, the cyanobacterial PII-interacting protein X (PipX) interacts with the global transcriptional regulator NtcA and the signal transduction protein PII, a protein found in all three domains of life as an integrator of signals of the nitrogen and carbon balance. PipX can form alternate complexes with NtcA and PII, and these interactions are stimulated and inhibited, respectively, by 2-oxoglutarate, providing a mechanistic link between PII signaling and NtcA-regulated gene expression. Here, we demonstrate that PipX is involved in a much wider interaction network. The effect of pipX alleles on transcript levels was studied by RNA sequencing of S. elongatus strains grown in the presence of either nitrate or ammonium, followed by multivariate analyses of relevant mutant/control comparisons. As a result of this process, 222 genes were classified into six coherent groups of differentially regulated genes, two of which, containing either NtcA-activated or NtcA-repressed genes, provided further insights into the function of NtcA–PipX complexes. The remaining four groups suggest the involvement of PipX in at least three NtcA-independent regulatory pathways. Our results pave the way to uncover new regulatory interactions and mechanisms in the control of gene expression in cyanobacteria.