Emission analysis of RE3+ (RE = Sm,Dy):B2O3‐TeO2‐Li2O‐AlF3 glasses

This article reports on the optical properties of 0.5% mol of Sm³⁺, Dy³⁺ ion‐doped B₂O₃‐TeO₂‐Li₂O‐AlF₃ (LiAlFBT) glasses. The glass samples were characterized by optical absorption and emission spectra. Judd‐Ofelt theory was applied to analyze the optical absorption spectra and calculate the intensity parameters and radiative properties of the emission transitions. The emission spectra of Sm³⁺ and Dy³⁺:LiAlFBT glasses showed a bright reddish‐orange emission at 598 nm (⁴G_5/2 → ⁶H_7/2) and an intense yellow emission at 574 nm (⁴F_9/2 → ⁶H_13/2), respectively. Full width at half maximum (FWHM), stimulated emission cross section, gain bandwidth and optical gain values were also calculated to extend the applications of the Sm³⁺ and Dy³⁺:LiAlFBT glasses. Copyright © 2012 John Wiley & Sons, Ltd.     

Observation of Solvent Penetration during Cold Denaturation of E.?coli Phosphofructokinase-2

Phosphofructokinase-2 is a dimeric enzyme that undergoes cold denaturation following a highly cooperative N₂ 2I mechanism with dimer dissociation and formation of an expanded monomeric intermediate. Here, we use intrinsic fluorescence of a tryptophan located at the dimer interface to show that dimer dissociation occurs slowly, over several hours. We then use hydrogen-deuterium exchange mass spectrometry experiments, performed by taking time points over the cold denaturation process, to measure amide exchange throughout the protein during approach to the cold denatured state. As expected, a peptide corresponding to the dimer interface became more solvent exposed over time at 3°C; unexpectedly, amide exchange increased throughout the protein over time at 3°C. The rate of increase in amide exchange over time at 3°C was the same for each region and equaled the rate of dimer dissociation measured by tryptophan fluorescence, suggesting that dimer dissociation and formation of the cold denatured intermediate occur without appreciable buildup of folded monomer. The observation that throughout the protein amide exchange increases as phosphofructokinase-2 cold denatures provides experimental evidence for theoretical predictions that cold denaturation primarily occurs by solvent penetration into the hydrophobic core of proteins in a sequence-independent manner.     

Ubiquitin Ser65 phosphorylation affects ubiquitin structure,chain assembly and hydrolysis

The protein kinase PINK1 was recently shown to phosphorylate ubiquitin (Ub) on Ser65, and phosphoUb activates the E3 ligase Parkin allosterically. Here, we show that PINK1 can phosphorylate every Ub in Ub chains. Moreover, Ser65 phosphorylation alters Ub structure, generating two conformations in solution. A crystal structure of the major conformation resembles Ub but has altered surface properties. NMR reveals a second phosphoUb conformation in which β5-strand slippage retracts the C-terminal tail by two residues into the Ub core. We further show that phosphoUb has no effect on E1-mediated E2 charging but can affect discharging of E2 enzymes to form polyUb chains. Notably, UBE2R1- (CDC34), UBE2N/UBE2V1- (UBC13/UEV1A), TRAF6- and HOIP-mediated chain assembly is inhibited by phosphoUb. While Lys63-linked poly-phosphoUb is recognized by the TAB2 NZF Ub binding domain (UBD), 10 out of 12 deubiquitinases (DUBs), including USP8, USP15 and USP30, are impaired in hydrolyzing phosphoUb chains. Hence, Ub phosphorylation has repercussions for ubiquitination and deubiquitination cascades beyond Parkin activation and may provide an independent layer of regulation in the Ub system.     

Neural Processing of Emotional Facial and Semantic Expressions in Euthymic Bipolar Disorder (BD) and Its Association with Theory of Mind (ToM)

Background

Adults with bipolar disorder (BD) have cognitive impairments that affect face processing and social cognition. However, it remains unknown whether these deficits in euthymic BD have impaired brain markers of emotional processing.

Methodology/Principal Findings

We recruited twenty six participants, 13 controls subjects with an equal number of euthymic BD participants. We used an event-related potential (ERP) assessment of a dual valence task (DVT), in which faces (angry and happy), words (pleasant and unpleasant), and face-word simultaneous combinations are presented to test the effects of the stimulus type (face vs word) and valence (positive vs. negative). All participants received clinical, neuropsychological and social cognition evaluations. ERP analysis revealed that both groups showed N170 modulation of stimulus type effects (face > word). BD patients exhibited reduced and enhanced N170 to facial and semantic valence, respectively. The neural source estimation of N170 was a posterior section of the fusiform gyrus (FG), including the face fusiform area (FFA). Neural generators of N170 for faces (FG and FFA) were reduced in BD. In these patients, N170 modulation was associated with social cognition (theory of mind).

Conclusions/Significance

This is the first report of euthymic BD exhibiting abnormal N170 emotional discrimination associated with theory of mind impairments.     

Optimization of mycophenolic acid production in solid state fermentation using response surface methodology

Mycophenolic acid (MPA) can be produced in solid state fermentation. An isolate of Penicillium brevi-compactum ATCC 16024 grown on moist wheat bran produced a titre of 425 mg per kg of wheat bran. Central composite rotatable design and response surface methodology were employed to derive a statistical model for media optimization towards production of mycophenolic acid. Five levels with a five factorial design were adopted. The correlation coefficient was 0.82, ensuring a satisfactory adjustment of the model to the experimental values. This statistical design was very effective in improving the titre of mycophenolic acid up to 3286 mg per kg of wheat bran. Received 24 July 1998/ Accepted in revised form 4 December 1998     

Purification and characterization of a transgenic corn grain‐derived recombinant collagen type I alpha 1

Corn offers advantages as a transgenic host for producing recombinant proteins required at large volumes (1,000's of tons per year) and low cost (less than US$50/kg) by generating them as co‐products of biorefining. We describe the purification and characterization of a corn grain‐derived mammalian structural protein having such market characteristics: a full length recombinant collagen type I alpha 1 (rCIα1) chain. Material properties of interest are gelation behavior, which would depend on as yet unverified ability of corn to carry out post‐translational prolyl hydroxylation and formation of triple helical conformation. The starting material was grain where the expression of rCIα1 had been directed by an embryo‐specific promoter. Purification consisted of extraction at low pH followed by membrane and chromatographic steps to isolate rCIα1 for characterization. The amino acid composition and immunoreactivity of CIα1 was similar to that of an analogous native human CIα1 and to rCIα1 produced by the yeast Pichia pastoris. Tandem mass spectrometry confirmed the primary sequence of the corn‐derived rCIα1 with 46% coverage. Fragments of the rCIα1chains were also observed, possibly caused by endogenous plant proteases. The corn‐derived rCIα1 had a low level of prolyl hydroxylation (～1% versus 11%) relative to animal‐derived CIα1 and folded into its characteristic triple‐helical structure as indicated by its resistance to pepsin digestion below its melting temperature of 26^oC. The 29 amino acid foldon fused to the C‐terminus to initiate triple helix formation was not cleaved from the rCIα1chains, but could be removed by pepsin treatment. © 2009 American Institute of Chemical Engineers Biotechnol. Prog. 2009     

Uncoupling the MgATP-induced inhibition and aggregation of Escherichia coli phosphofructokinase-2 by C-terminal mutations

Binding of MgATP to an allosteric site of Escherichia coli phosphofructokinase-2 (Pfk-2) provoked inhibition and a dimer-tetramer (D-T) conversion of the enzyme. Successive deletions of up to 10 residues and point mutations at the C-terminal end led to mutants with elevated K(Mapp) values for MgATP which failed to show the D-T conversion, but were still inhibited by the nucleotide. Y306 was required for the quaternary packing involved in the D-T conversion and the next residue, L307, was crucial for the ternary packing necessary for the catalytic MgATP-binding site. These results show that the D-T conversion could be uncoupled from the conformational changes that lead to the MgATP-induced allosteric inhibition.     

Cloning and characterization of Rhesus monkey neuropeptide Y receptor subtypes

Neuropeptide Y (NPY) is a 36 amino acid peptide that is abundant in the brain and peripheral nervous system. NPY has a variety of effects when administered into the brain including a pronounced feeding effect, anxiolysis, regulation of neuroendocrine axes and inhibition of neurotransmitter release. These effects are mediated by up to 6 G protein coupled receptors designated Y1, Y2, Y3, Y4, Y5 and y6. To better understand the phylogeny and pharmacology of NPY in non-human primates, we have cloned and expressed the NPY Y1, Y2 and Y5 receptor subtypes from the Rhesus monkey. No cDNA sequence encoding a Y4 receptor was found suggesting substantial sequence differences when compared to the human sequence. Comparison of these sequences with those from human indicated strong sequence conservation of Y1, Y2 and Y5 between the two species. The displacement of (125)I-PYY binding to the Rhesus monkey and human receptors by various peptides was compared to evaluate the pharmacology of the two species. Similar pharmacologies were noted across the species at the various receptor subtypes. These results indicate the Rhesus monkey and human NPY receptor subtypes have a close amino acid sequence conservation and that the peptide recognition domains are conserved as well.     

Congenital deformity of the paw in a captive tiger: case report

Background

Although Morbillivirus and Toxoplasma gondii have emerged as important pathogens for several cetaceans populations over the last 20 years, they have never been identified together in a Mysticete. In particular, morbilliviral infection has been never described in the Mediterranean fin whale population.

Case presentation

On January 2011 an adult male of fin whale (Balaenoptera physalus) stranded along the Tyrrhenian coastline of Italy. During necropsy, tissue samples from heart, skeletal muscle, mesenteric lymph nodes, liver, spleen, lung, and kidney were collected and subsequently analyzed for Morbillivirus and Toxoplasma gondii by microscopic and molecular methods. Following the detailed necropsy carried out on this whale, molecular analysis revealed, for the first time, the simultaneous presence of a Dolphin Morbillivirus (DMV) and T. gondii infection coexisting with each other, along with high organochlorine pollutant concentrations, with special reference to DDT.

Conclusion

This report, besides confirming the possibility for Mysticetes to be infected with DMV, highlights the risk of toxoplasmosis in sea water for mammals, already immunodepressed by concurrent factors as infections and environmental contaminants.