University of Portsmouth

About: University of Portsmouth is a education organization based out in Portsmouth, Portsmouth, United Kingdom. It is known for research contribution in the topics: Population & Galaxy. The organization has 5452 authors who have published 14256 publications receiving 424346 citations. The organization is also known as: Portsmouth and Gosport School of Science and Art & Portsmouth and Gosport School of Science and the Arts.

Galaxy And Mass Assembly (GAMA): the input catalogue and star–galaxy separation

Abstract: We describe the spectroscopic target selection for the Galaxy And Mass Assembly (GAMA) survey. The input catalogue is drawn from the Sloan Digital Sky Survey (SDSS) and UKIRT Infrared Deep Sky Survey (UKIDSS). The initial aim is to measure redshifts for galaxies in three 4 ◦ × 12 ◦ regions at 9, 12 and 14.5 h, on the celestial equator, with magnitude selections r< 19.4, z< 18.2 and K AB < 17.6 over all three regions, and r< 19.8 in the 12-h region. The target density is 1080 deg −2 in the 12-h region and 720 deg −2 in the other regions. The average GAMA target density and area are compared with completed and ongoing galaxy redshift surveys. The GAMA survey implements a highly complete star–galaxy separation that jointly uses an intensity-profile separator (� sg = r psf − r model as per the SDSS) and a

Important role of matrix metalloproteinase 9 in epileptogenesis

Abstract: Temporal lobe epilepsy (TLE) is a devastating disease in which aberrant synaptic plasticity plays a major role. We identify matrix metalloproteinase (MMP) 9 as a novel synaptic enzyme and a key pathogenic factor in two animal models of TLE: kainate-evoked epilepsy and pentylenetetrazole (PTZ) kindling–induced epilepsy. Notably, we show that the sensitivity to PTZ epileptogenesis is decreased in MMP-9 knockout mice but is increased in a novel line of transgenic rats overexpressing MMP-9. Immunoelectron microscopy reveals that MMP-9 associates with hippocampal dendritic spines bearing asymmetrical (excitatory) synapses, where both the MMP-9 protein levels and enzymatic activity become strongly increased upon seizures. Further, we find that MMP-9 deficiency diminishes seizure-evoked pruning of dendritic spines and decreases aberrant synaptogenesis after mossy fiber sprouting. The latter observation provides a possible mechanistic basis for the effect of MMP-9 on epileptogenesis. Our work suggests that a synaptic pool of MMP-9 is critical for the sequence of events that underlie the development of seizures in animal models of TLE.

DNA methylation models histone acetylation

Abstract: One of the main determinants of chromatin structure is histone acetylation1. Local chromosomal acetylation can be regulated dynamically, both through the involvement of transactivating factors with intrinsic histone acetylase activity, and through the recruitment of deacetylase complexes that repress gene expression2. Histone acetylation status is transiently modified from one state to another in response to physiological changes operating in the cell. It is not yet known, however, how the basic histone acetylation profiles on tissue-specific and housekeeping gene sequences are established during normal development. Here we show that DNA methylation takes part in this process by inducing decreased levels of chromatin acetylation.