1,127 research outputs found
Pax3 and Pax7 are expressed in commissural neurons and restrict ventral neuronal identity in the spinal cord
Early mesodermal phenotypes in splotch suggest a role for Pax3 in the formation of epithelial somites
Large Charge Four-Dimensional Non-Extremal N=2 Black Holes with R^2-Terms
We consider N=2 supergravity in four dimensions with small R^2 curvature
corrections. We construct large charge non-extremal black hole solutions in all
space, with either a supersymmetric or a non-supersymmetric extremal limit, and
analyze their thermodynamic properties. This generalizes some of the extremal
solutions presented in [arXiv:0902.0831]. The indexed entropy of the
non-extremal extension of the supersymmetric black hole, has the form of the
extremal entropy, with the charges replaced by a function of the charges, the
moduli at infinity and the non-extremality parameter. This is the same behavior
as in the case without R^2-terms.Comment: 13 pages. v2: stripped down to letter format, based on the background
given in [arXiv:0902.0831]. v3: up to date with CQG versio
Large Charge Four-Dimensional Extremal N=2 Black Holes with R^2-Terms
We consider N=2 supergravity in four dimensions with small R^2 curvature
corrections. We construct large charge extremal supersymmetric and
non-supersymmetric black hole solutions in all space, and analyze their
thermodynamic properties.Comment: 18 pages. v2,3: minor fixe
Identification of the lactococcal exonuclease/recombinase and its modulation by the putative Chi sequence
Studies of RecBCD–Chi interactions in Escherichia coli have served as a model to understand recombination events in bacteria. However, the existence of similar interactions has not been demonstrated in bacteria unrelated to E. coli. We developed an in vivo model to examine components of dsDNA break repair in various microorganisms. Here, we identify the major exonuclease in Lactococcus lactis, a Gram-positive organism evolutionarily distant from E. coli, and provide evidence for exonuclease–Chi interactions. Insertional mutants of L. lactis, screened as exonuclease-deficient, affected a single locus and resulted in UV sensitivity and recombination deficiency. The cloned lactococcal genes (called rexAB) restored UV resistance, recombination proficiency, and the capacity to degrade linear DNA, to an E. coli recBCD mutant. In this context, DNA degradation is specifically blocked by the putative lactococcal Chi site (5′-GCGCGTG-3′), but not by the E. coli Chi (5′-GCTGGTGG-3′) site. RexAB-mediated recombination was shown to be stimulated ≈27-fold by lactococcal Chi. Our results reveal that RexAB fulfills the biological roles of RecBCD and indicate that its activity is modulated by a short DNA sequence. We speculate that exonuclease/recombinase enzymes whose activities are modulated by short DNA sequences are widespread among bacteria
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