The mass function of the Las Campanas loose groups of galaxies

We have determined the mass function of loose groups of galaxies in the Las Campanas Redshift Survey. Loose groups of galaxies in the LCRS range in mass from M \sim 10^{12} {\rm M}_{\sun} to 10^{15} {\rm M}_{\sun}. We find that the sample is almost complete for masses in the interval 5\cdot 10^{13}-8\cdot 10^{14} {\rm M}_{\sun}. Comparison of the observed mass function with theoretical mass functions obtained from N-body simulations shows good agreement with a CDM model with the parameters $\Omega_m = 0.3$, $\Omega_{\Lambda} = 0.7$ and the amplitude of perturbations about $\sigma_8=0.78-0.87$. For smaller masses the mass function of LCRS loose groups flattens out, differing considerably from the group mass function found by Girardi and Giuricin (2000) and from mass functions obtained by numerical simulations.Comment: 9 pages, 7 figures, AA accepte

Insights into the effects of N-glycosylation on the characteristics of the VC1 domain of the human receptor for advanced glycation end products (RAGE) secreted by Pichia pastoris

Advanced glycation end products (AGEs) and advanced lipoxidation end products (ALEs), resulting from non-enzymatic modifications of proteins, are potentially harmful to human health. They directly act on proteins, affecting structure and function, or through receptor-mediated mechanisms. RAGE, a type I transmembrane glycoprotein, was identified as a receptor for AGEs. RAGE is involved in chronic inflammation, oxidative stress-based diseases and ageing. The majority of RAGE ligands bind to the VC1 domain. This domain was successfully expressed and secreted by Pichia pastoris. Out of two N-glycosylation sites, one (Asn25) was fully occupied while the other (Asn81) was under-glycosylated, generating two VC1 variants, named p36 and p34. Analysis of N-glycans and of their influence on VC1 properties were here investigated. The highly sensitive procainamide labeling method coupled to ES-MS was used for N-glycan profiling. N-glycans released from VC1 ranged from Man9GlcNAc2- to Man15GlcNAc2- with major Man10GlcNAc2- and Man11GlcNAc2- species for p36 and p34, respectively. Circular dichroism spectra indicated that VC1 maintains the same conformation also after removal of N-glycans. Thermal denaturation curves showed that the carbohydrate moiety has a small stabilizing effect on VC1 protein conformation. The removal of the glycan moiety did not affect the binding of VC1 to sugar-derived AGE- or malondialdehyde-derived ALE-human serum albumin. Given the crucial role of RAGE in human pathologies, the features of VC1 from P. pastoris will prove useful in designing strategies for the enrichment of AGEs/ALEs from plasma, urine or tissues, and in characterizing the nature of the interaction

Imine Deaminase Activity and Conformational Stability of UK114, the Mammalian Member of the Rid Protein Family Active in Amino Acid Metabolism

Abstract: Reactive intermediate deaminase (Rid) protein family is a recently discovered group of enzymes that is conserved in all domains of life and is proposed to play a role in the detoxification of reactive enamines/imines. UK114, the mammalian member of RidA subfamily, was identified in the early 90s as a component of perchloric acid-soluble extracts from goat liver and exhibited immunomodulatory properties. Multiple activities were attributed to this protein, but its function is still unclear. This work addressed the question of whether UK114 is a Rid enzyme. Biochemical analyses demonstrated that UK114 hydrolyzes -imino acids generated by L- or D-amino acid oxidases with a preference for those deriving from Ala > Leu = L-Met > L-Gln, whereas it was poorly active on L-Phe and L-His. Circular Dichroism (CD) analyses of UK114 conformational stability highlighted its remarkable resistance to thermal unfolding, even at high urea concentrations. The half-life of heat inactivation at 95 C, measured from CD and activity data, was about 3.5 h. The unusual conformational stability of UK114 could be relevant in the frame of a future evaluation of its immunogenic properties. In conclusion, mammalian UK114 proteins are RidA enzymes that may play an important role in metabolism homeostasis also in these organisms

Two Novel Fish Paralogs Provide Insights Into the Rid Family of Imine Deaminases Active in Pre-Empting enamine/imine Metabolic Damage

Reactive Intermediate Deaminase (Rid) protein superfamily includes eight families among which the RidA is conserved in all domains of life. RidA proteins accelerate the deamination of the reactive 2-aminoacrylate (2AA), an enamine produced by some pyridoxal phosphate (PLP)-dependent enzymes. 2AA accumulation inhibits target enzymes with a detrimental impact on fitness. As a consequence of whole genome duplication, teleost fish have two ridA paralogs, while other extant vertebrates contain a single-copy gene. We investigated the biochemical properties of the products of two paralogs, identified in Salmo salar. SsRidA-1 and SsRidA-2 complemented the growth defect of a Salmonella enterica ridA mutant, an in vivo model of 2AA stress. In vitro, both proteins hydrolyzed 2-imino acids (IA) to keto-acids and ammonia. SsRidA-1 was active on IA derived from nonpolar amino acids and poorly active or inactive on IA derived from other amino acids tested. In contrast, SsRidA-2 had a generally low catalytic efficiency, but showed a relatively higher activity with IA derived from L-Glu and aromatic amino acids. The crystal structures of SsRidA-1 and SsRidA-2 provided hints of the remarkably different conformational stability and substrate specificity. Overall, SsRidA-1 is similar to the mammalian orthologs whereas SsRidA-2 displays unique properties likely generated by functional specialization of a duplicated ancestral gene

On the cosmological mass function theory

This paper provides, from one side, a review of the theory of the cosmological mass function from a theoretical point of view, starting from the seminal paper of Press & Shechter (1974) to the last developments (Del Popolo & Gambera (1998, 1999), Sheth & Tormen 1999 (ST), Sheth, Mo & Tormen 2001 (ST1), Jenkins et al. 2001 (J01), Shet & Tormen 2002 (ST2), Del Popolo 2002a, Yagi et al. 2004 (YNY)), and from another side some improvements on the multiplicity function models in literature. ...Comment: Astronomy Reports, in prin

Metacognition Is Necessary for the Emergence of Motivation in People With Schizophrenia Spectrum Disorders: A Necessary Condition Analysis

Metacognition deficits are a putative cause of reduced motivation in people with schizophrenia spectrum disorders. However, it is unclear whether certain levels of metacognition are necessary for motivation to emerge. This study used a Necessary Condition Analysis (NCA) to test whether metacognition was necessary for the presence of motivation and to identify the minimum level of metacognition necessary for high motivation to be possible in people with schizophrenia spectrum disorders (N=175). Participants completed clinician-rated measures of metacognition and motivation. NCA revealed that metacognition is a necessary condition for motivation and that high levels of motivation were only possible, although not guaranteed, when at least a basic level of metacognition was present. Findings suggest that metacognition is a necessary building block for the development of motivation. Results suggest that targeting metacognition may be essential for improving motivation among people with schizophrenia spectrum disorders who do not meet this metacognition threshold

Correlation between membrane bending and lipidic composition during the sperm acrosomal exocytosis : computational analysis

Fil: Suhaiman, L..Fil: Borioni, J.L..Fil: Ferguson, M..Fil: Belmonte, S..Fil: Del Popolo, M. G.