Synthesis and luminescence properties of Ca3Ga2Si3O12:RE3+ (RE = Eu/Tb) powder phosphors

Rare earth ions (Eu³⁺ or Tb³⁺)‐activated Ca₃ Ga₂ Si₃O₁₂ (CaGaSi) phosphors were synthesized by using a sol–gel method. Photoluminescence spectra of Eu³⁺:CaGaSi phosphors exhibited five emission bands at 578, 592, 612, 652 and 701 nm, which were assigned to the transitions (⁵D₀ → ⁷F₀, ⁷F_1, ⁷F₂, ⁷F₃ and ⁷F₄), respectively, with an excitation wavelength of λ_exci = 392 nm. Among these, the transition ⁵D₀ → ⁷F₂ (612 nm) displayed bright red emission. In the case of Tb³⁺:CaGaSi phosphors, four emission bands were observed at 488 (⁵D₄ → ⁷F₆), 543 (⁵D₄ → ⁷F₅), 584 (⁵D₄ → ⁷F₄) and 614 nm (⁵D₄ → ⁷F₃) from the measurement of PL spectra with λ_exci = 376 nm. Among these, the transition ⁵D₄ → ⁷F₅ at 543 nm displayed bright green emission. The structure and morphology of the phosphors were studied from the measurements of X‐ray diffraction (XRD), scanning electron microscopy (SEM) and energy‐dispersive X‐ray analysis (EDAX) results. Copyright © 2011 John Wiley & Sons, Ltd.     

A general method to quantify quasi-equivalence in icosahedral viruses

A quantitative, atom-based, method is described for comparing protein subunit interfaces in icosahedral virus capsids with quasi-equivalent surface lattices. An integrated, normalized value (between 0 and 1) based on equivalent residue contacts (Q-score) is computed for every pair of subunit interactions and scores that are significantly above zero readily identify interfaces that are quasi-equivalent to each other. The method was applied to all quasi-equivalent capsid structures (T=3, 4, 7 and 13) in the Protein Data Bank and the Q-scores were interpreted in terms of their structural underpinnings. The analysis allowed classification of T=3 structures into three groups with architectures that resemble different polyhedra with icosahedral symmetry. The preference of subunits to form dimers in the T=4 human Hepatitis B virus capsid (HBV) was clearly reflected in high Q-scores of quasi-equivalent dimers. Interesting differences between the classical T=7 capsid and polyoma-like capsids were also identified. Application of the method to the outer-shell of the T=13 Blue tongue virus core (BTVC) highlighted the modest distortion between the interfaces of the general trimers and the strict trimers of VP7 subunits. Furthermore, the method identified the quasi 2-fold symmetry in the inner capsids of the BTV and reovirus cores. The results show that the Q-scores of various quasi-symmetries represent a "fingerprint" for a particular virus capsid architecture allowing particle classification into groups based on their underlying structural and geometric features.     

Solid Phase and Solution Phase Synthesis of Gamma Amino Acid Homo-Oligomers and Mixed Oligomers

Abstract  

An efficient stepwise synthesis of homo-oligomers and mixed oligomers of gabapentin and pregabalin on solid support using Fmoc-protected derivatives and HBTU/HOBt/DIEA as coupling agent is described. The synthesis was also carried out using solution phase methodology. The Gpn/Pgn homo oligomers and mixed oligomers forms C₉ helix in solution as determined by NMR study. Chiral as well as achiral gamma amino acids were used for the synthesis of oligomers in order to investigate the secondary structural preferences.     

Antiinflammatory and antiulcer activities of phytic acid in rats

Maximum antiinflammatory activity of phytic acid (PA) was seen at an oral dose of 150 mg/kg in the carrageenan induced rat paw edema model. Although PA showed ability to prevent denaturation of proteins, it showed less antiinflammatory activity than ibuprofen. Ability of PA to bring down thermal denaturation of proteins might be a contributing factor in the mechanism of action against inflammation. PA, at all the doses tested, showed significant protection from ulcers induced by ibuprofen, ethanol and cold stress, with a maximum activity at 150 mg/kg. There was a significant increase in gastric tissue malondialdehyde levels in ethanol treated rats but these levels decreased following PA pretreatment. Moreover, pretreatment with PA significantly inhibited various effects of ethanol on gastric mucosa, such as, reduction in the concentration of nonprotein sulfhydryl groups, necrosis, erosions, congestion and hemorrhage. These results suggested that gastro-protective effect of PA could be mediated by its antioxidant activity and cytoprotection of gastric mucosa.     

Amyotrophic lateral sclerosis-linked FUS/TLS alters stress granule assembly and dynamics

Background

Amyotrophic lateral sclerosis (ALS)-linked fused in sarcoma/translocated in liposarcoma (FUS/TLS or FUS) is concentrated within cytoplasmic stress granules under conditions of induced stress. Since only the mutants, but not the endogenous wild-type FUS, are associated with stress granules under most of the stress conditions reported to date, the relationship between FUS and stress granules represents a mutant-specific phenotype and thus may be of significance in mutant-induced pathogenesis. While the association of mutant-FUS with stress granules is well established, the effect of the mutant protein on stress granules has not been examined. Here we investigated the effect of mutant-FUS on stress granule formation and dynamics under conditions of oxidative stress.

Results

We found that expression of mutant-FUS delays the assembly of stress granules. However, once stress granules containing mutant-FUS are formed, they are more dynamic, larger and more abundant compared to stress granules lacking FUS. Once stress is removed, stress granules disassemble more rapidly in cells expressing mutant-FUS. These effects directly correlate with the degree of mutant-FUS cytoplasmic localization, which is induced by mutations in the nuclear localization signal of the protein. We also determine that the RGG domains within FUS play a key role in its association to stress granules. While there has been speculation that arginine methylation within these RGG domains modulates the incorporation of FUS into stress granules, our results demonstrate that this post-translational modification is not involved.

Conclusions

Our results indicate that mutant-FUS alters the dynamic properties of stress granules, which is consistent with a gain-of-toxic mechanism for mutant-FUS in stress granule assembly and cellular stress response.

     

Determination of isocyanate specific albumin-adducts in workers exposed to toluene diisocyanates

Toluene diisocyanates (2,4-TDI and 2,6-TDI) are important intermediates in the chemical industry. Among the main damages after low levels of TDI exposure are lung sensitization and asthma. It is therefore necessary to have sensitive and specific methods to monitor isocyanate exposure of workers. Urinary metabolites or protein adducts have been used as biomarkers in workers exposed to TDI. However, with these methods it was not possible to determine if the biomarkers result from exposure to TDI or to the corresponding toluene diamines (TDA). This work presents a new procedure for the determination of isocyanate-specific albumin adducts. Isotope dilution mass spectrometry was used to measure the adducts in albumin present in workers exposed to TDI. 2,4-TDI and 2,6-TDI formed adducts with lysine: N(?)-[({3-amino-4-methylphenyl}amino)carbonyl]-lysine, N(?)-[({5-amino-2-methylphenyl}amino)carbonyl]-lysine, and N(?)- [({3-amino-2-methylphenyl}amino)carbonyl]-lysine. In future studies, this new method can be applied to measure TDI-exposures in workers.     

Virus isolation and molecular epidemiology of highly pathogenic avian influenza A(H5N8) from an outbreak in free-ranging wild birds,India 2016

We report the molecular epidemiology of highly pathogenic avian influenza (HPAI) virus involved in an outbreak causing death in free-ranging wild birds at Mysore, Karnataka state of India. The virus was typed as HPAI A(H5N8) by conventional and TaqMan probe based real-time PCR assays. Six isolates of HPAI virus were recovered in 9-day-old embryonated chicken eggs. Haemagglutinin gene-based phylogeny of virus isolates showed >?99.9% nucleotide sequence identity with HPAI A(H5N8) isolates from migratory birds and domestic poultry from China and Korea indicating either these wild birds have routed their migration through Korea and/or eastern China or these dead birds must have directly or indirectly contacted with wild birds migrating from Eastern China and/or Korean regions. The study emphasises the role of migratory wild birds in spread of HPAI across the globe.     

Immunohistochemical Demonstration of Leptin in Pancreatic Islets of Non-Obese Diabetic and CD-1 mice: Co-localization in Glucagon Cells and its Attenuation at the Onset of Diabetes

Leptin is a 16 kD polypeptide hormone produced predominantly by white adipose tissue and exerts profound effects on food intake and energy balance. More recent studies have shown extra sites of leptin production in human and rodent tissues and have ascribed additional roles for the hormone, e.g., in immune and reproductive functions. A role for the hormone has also been implicated in insulin-dependent diabetes mellitus in the non-obese diabetic (NOD) mouse. However, whether leptin originates from islet cells of the mouse is not known. Here dual-label immunohistochemistry was employed to examine leptin expression in islet cells, and its distribution and cellular sources in pancreatic sections of female NOD/Ak and CD-1 mice of various ages. For comparison, leptin immunolabelling was examined in adult pancreatic sections from male NOD/Ak CD-1, Balb/c and FVB/N mice and female severe combined immunodeficient CB. 17 mice. Pancreatic tissues from adult female guinea pig, sheep and cattle and neonatal pigs were also studied. Our results show that in the day 1 NOD and CD-1 mice, leptin immunolabelling was observed in selective glucagon cells within the developing islets while at days 15 and 22, it became more intense and co-incident. This pattern of staining was maintained at days 40, 90, 150 and 250. In the female NOD mouse, leptin was absent in intra-islet immune cells. Its expression was variable in islets from male NOD and CD-1 mice. In spontaneously diabetic female NOD mice and following acceleration of diabetes with cyclophosphamide, despite the persistence of strong immunolabelling for glucagon in the re-distributed alpha cells, leptin expression was either absent, diminished or present in only a proportion of alpha cells. The reduction in leptin labelling was often associated with diabetic islets which had insulitis in association with only a small number of residual beta cells. Leptin expression was absent in guinea pig, ovine, bovine and neonatal porcine islet cells, despite the expression of intensely labelled glucagon cells. The present results demonstrate leptin co-localization in glucagon cells of the mouse islet. Its expression diminishes in the presence of inadequate insulin. Leptin produced within the mouse islet may have bi-directional influences on leptin and insulin regulation and may play local functions in islet development and metabolism.