Growth of Namibian silver kob agyrosomus inodorus based on Otoliths and mark-recapture data

The growth of silver kob Argyrosomus inodorus sampled from two regions (northern and southern) along the Namibian coast was determined using longitudinally sectioned otoliths. The special Von Bertalanffy growthmodel adequately described the growth of kob in both regions. Growth rate for kob in the south was validated using mark-recapture data, and similar growth rates were obtained using both methods. Growth of kob sampledin the south (maximum age 19 years) was significantly different from those in the north (maximum age 28 years). Kob from the two regions appeared to be from the same stock, and consequently length-at-age data from the regions can be pooled for management purposes. Growth of Namibian silver kob was markedly different from the South African silver kob, for which growth was best described by logistic (South-Western Cape) and Richards (Southern and South-Eastern Cape) models. The special Von Bertalanffy growth parameters were determined by the equations:Lt = 116 (1–e0.120 (t + 1.47)) mm for the southern region,Lt = 112 (1–e–0.094 (t + 2.29)) mm for the northern regions,Lt = 103 (1–e–0.136 (t + 1.58)) mm for both regions combined

Observations on the linefish resources of Namibia, 1990–2000, with special reference to West Coast steenbras and silver kob

The Namibian linefishery is a multisector fishery, with recreational and commercial sectors argeting overlapping species. Prior to 1990, catch data were recorded for the boat sector, but little research was done on the population dynamics of any of the species. Hence, none of the stocks were assessed owing to the lack of parameter estimates for fisheries modelling. Current management regulations for the Namibian linefishery are therefore not based on scientific investigations but, for historical reasons, were adapted from South African legislation for similar species. From 1994, linefish research in Namibia focused on the life history and population dynamics of silver kob Argyrosomus inodorus and West Coast steenbras Lithognathus aureti, important species in both commercial and recreational sectors. A roving-roving creel survey was used to determine effort and catches of recreational shore-anglers. Both species were assessed using yield-per-recruit models. Based on the results, reduced daily bag limits and the implementation of size limits for the recreational sector were proposed. For the commercial sector, the introduction of a total allowable catch would seem to be the best option. Results from an economic survey indicated that the recreational sector earns six times more for the country annually than the commercial sector. Keywords: creel survey, economics, genetics, migration, silver kob, West Coast steenbras, yield-per-recruitAfrican Journal of Marine Science 2001, 23: 135–14

O-Glycosylation Regulates Ubiquitination and Degradation of the Anti-Inflammatory Protein A20 to Accelerate Atherosclerosis in Diabetic ApoE-Null Mice

Background: Accelerated atherosclerosis is the leading cause of morbidity and mortality in diabetic patients. Hyperglycemia is a recognized independent risk factor for heightened atherogenesis in diabetes mellitus (DM). However, our understanding of the mechanisms underlying glucose damage to the vasculature remains incomplete. Methodology/Principal Findings: High glucose and hyperglycemia reduced upregulation of the NF-κB inhibitory and atheroprotective protein A20 in human coronary endothelial (EC) and smooth muscle cell (SMC) cultures challenged with Tumor Necrosis Factor alpha (TNF), aortae of diabetic mice following Lipopolysaccharide (LPS) injection used as an inflammatory insult and in failed vein-grafts of diabetic patients. Decreased vascular expression of A20 did not relate to defective transcription, as A20 mRNA levels were similar or even higher in EC/SMC cultured in high glucose, in vessels of diabetic C57BL/6 and FBV/N mice, and in failed vein grafts of diabetic patients, when compared to controls. Rather, decreased A20 expression correlated with post-translational O-Glucosamine-N-Acetylation (O-GlcNAcylation) and ubiquitination of A20, targeting it for proteasomal degradation. Restoring A20 levels by inhibiting O-GlcNAcylation, blocking proteasome activity, or overexpressing A20, blocked upregulation of the receptor for advanced glycation end-products (RAGE) and phosphorylation of PKCβII, two prime atherogenic signals triggered by high glucose in EC/SMC. A20 gene transfer to the aortic arch of diabetic ApoE null mice that develop accelerated atherosclerosis, attenuated vascular expression of RAGE and phospho-PKCβII, significantly reducing atherosclerosis. Conclusions: High glucose/hyperglycemia regulate vascular A20 expression via O-GlcNAcylation-dependent ubiquitination and proteasomal degradation. This could be key to the pathogenesis of accelerated atherosclerosis in diabetes

The role of the proteasome in the generation of MHC class I ligands and immune responses

The ubiquitin–proteasome system (UPS) degrades intracellular proteins into peptide fragments that can be presented by major histocompatibility complex (MHC) class I molecules. While the UPS is functional in all mammalian cells, its subunit composition differs depending on cell type and stimuli received. Thus, cells of the hematopoietic lineage and cells exposed to (pro)inflammatory cytokines express three proteasome immunosubunits, which form the catalytic centers of immunoproteasomes, and the proteasome activator PA28. Cortical thymic epithelial cells express a thymus-specific proteasome subunit that induces the assembly of thymoproteasomes. We here review new developments regarding the role of these different proteasome components in MHC class I antigen processing, T cell repertoire selection and CD8 T cell responses. We further discuss recently discovered functions of proteasomes in peptide splicing, lymphocyte survival and the regulation of cytokine production and inflammatory responses

The sloan digital sky survey quasar catalog. II. First data release

We present the second edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog. The catalog consists of the 16,713 objects in the SDSS First Data Release that have luminosities larger than Mi = -22 (in a cosmology with H0 = 70 km s-1 Mpc-1, ΩM= 0.3, and Ω∇ = 0.7), have at least one emission line with FWHM larger than 1000 km s-1, and have highly reliable redshifts. The area covered by the catalog is ≈ 1360 deg 2. The quasar redshifts range from 0.08 to 5.41, with a median value of 1.43. For each object, the catalog presents positions accurate to better than 0.′2 rms per coordinate, five-band (ugriz) CCD-based photometry with typical accuracy of 0.03 mag, and information on the morphology and selection method. The catalog also contains some radio, near-infrared, and X-ray emission properties of the quasars, when available, from other large-area surveys. Calibrated digital spectra of all objects in the catalog, covering the wavelength region 3800-9200 Å at a spectral resolution of 1800-2100, are available. This publication supersedes the first SDSS Quasar Catalog, which was based on material from the SDSS Early Data Release. A summary of corrections to current quasar databases is also provided. The majority of the objects were found in SDSS commissioning data using a multicolor selection technique. Since the quasar selection algorithm was undergoing testing during the entire observational period covered by this catalog, care must be taken when assembling samples from the catalog for use in statistical studies. A total of 15,786 objects (94%) in the catalog were discovered by the SDSS; 12,173 of the SDSS discoveries are reported here for the first time. Included in the new discoveries are five quasars brighter than i= 16.0 and 17 quasars with redshifts larger than 4.5

The sloan digital sky survey quasar catalog. II. First data release

We present the second edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog. The catalog consists of the 16,713 objects in the SDSS First Data Release that have luminosities larger than Mi = -22 (in a cosmology with H0 = 70 km s-1 Mpc-1, ΩM= 0.3, and Ω∇ = 0.7), have at least one emission line with FWHM larger than 1000 km s-1, and have highly reliable redshifts. The area covered by the catalog is ≈ 1360 deg 2. The quasar redshifts range from 0.08 to 5.41, with a median value of 1.43. For each object, the catalog presents positions accurate to better than 0.′2 rms per coordinate, five-band (ugriz) CCD-based photometry with typical accuracy of 0.03 mag, and information on the morphology and selection method. The catalog also contains some radio, near-infrared, and X-ray emission properties of the quasars, when available, from other large-area surveys. Calibrated digital spectra of all objects in the catalog, covering the wavelength region 3800-9200 Å at a spectral resolution of 1800-2100, are available. This publication supersedes the first SDSS Quasar Catalog, which was based on material from the SDSS Early Data Release. A summary of corrections to current quasar databases is also provided. The majority of the objects were found in SDSS commissioning data using a multicolor selection technique. Since the quasar selection algorithm was undergoing testing during the entire observational period covered by this catalog, care must be taken when assembling samples from the catalog for use in statistical studies. A total of 15,786 objects (94%) in the catalog were discovered by the SDSS; 12,173 of the SDSS discoveries are reported here for the first time. Included in the new discoveries are five quasars brighter than i= 16.0 and 17 quasars with redshifts larger than 4.5