Growth Rate of Cosmological Perturbations at z∼0.1 from a New Observational Test.

Spatial variations in the distribution of galaxy luminosities, estimated from redshifts as distance proxies, are correlated with the peculiar velocity field. Comparing these variations with the peculiar velocities inferred from galaxy redshift surveys is a powerful test of gravity and dark-energy theories on cosmological scales. Using ∼2×10(5) galaxies from the SDSS Data Release 7, we perform this test in the framework of gravitational instability to estimate the normalized growth rate of density perturbations fσ8=0.

Cell movements controlled by the Notch signalling cascade during foregut development in Drosophila.

Notch signalling is an evolutionarily conserved cell interaction mechanism, the role of which in controlling cell fate choices has been studied extensively. Recent studies in both vertebrates and invertebrates revealed additional functions of Notch in proliferation and apoptotic events. We provide evidence for an essential role of the Notch signalling pathway during morphogenetic cell movements required for the formation of the foregut-associated proventriculus organ in the Drosophila embryo.

Cooperation of JAK/STAT and Notch signaling in the Drosophila foregut.

Temporal and spatial regulation of morphogenesis is pivotal to the formation of organs from simple epithelial tubes. In a genetic screen for novel genes controlling cell movement during posterior foregut development, we have identified and molecularly characterized two alleles of the domeless gene which encodes the Drosophila Janus kinase (JAK)/STAT receptor. We demonstrate that mutants for domeless or any other known component of the canonical JAK/STAT signaling pathway display a failure of coordinated cell movement during the development of the proventriculus, a multiply folded organ which is formed by stereotyped cell rearrangements in the posterior foregut.

Human osteoblast-like cells express predominantly steroid 5alpha-reductase type 1.

In previous studies we established that human bone and human osteoblast-like cells (hOB cells) cultured from bone express 5alpha-reductase (5alpha-R) activity, as demonstrated by the conversion of testosterone and androstenedione to their corresponding 5alpha-reduced metabolites, 5alpha-dihydrotestosterone (DHT) and 5alpha-androstanedione. Two 5alpha-R isozymes (types 1 and 2) have been identified in various tissues. As their nature in bone is unknown, we investigated which isozymes were expressed in first passage hOB cells cultured from bone specimens obtained from six donors (five women and one man).