Tract‐tracing study of the extrabulbar Olfactory projections in the brain of some teleosts

The extrabulbar olfactory projections (EBOP) is a collection of nerve fibers that originate from primary olfactory receptor neurons. These fibers penetrate into the brain, bypassing the olfactory bulbs (OBs). While the presence of an EBOP has been well established in teleosts, here we morphologically characterize the EBOP structure in four species each with a different morphological relationship of OB with the ventral telencephalic area. Tract‐tracing methods (carbocyanine DiI/DIA and biocytin) were used. FMRFamide immunoreactive nervus terminalis (NT) components were also visualized to define any neuroanatomical relationship between the NT and EBOP. Unilateral DiI/DiA application to the olfactory chamber stained the entire olfactory epithelium, olfactory nerve fibers, and ipsilateral olfactory bulb. Labeled primary olfactory fibers running ventromedially as extrabulbar primary olfactory projections reached various regions of the secondary prosencephalon. Only in Moenkhausia sanctaefilomenae (no olfactory peduncle) did lipophilic tracer‐labeled fibers reach the ipsilateral mesencephalon. The combination of tracing techniques and FMRFamide immunohistochemistry revealed a substantial overlap of the label along the olfactory pathways as well as in the anterior secondary prosencephalon. However, FMRFamide immunoreactivity was never colocalized in the same cellular or fiber component as visualized using tracer molecules. Our results showed a certain uniformity in the neuroanatomy and extension of EBOP in all four species, independent of the pedunculate feature of the OBs. The present study also provided additional evidence to support the view that EBOP and FMRFamide immunoreactive components of the NT are separate anatomical entities. Microsc. Res. Tech. 78:268–276, 2015. © 2015 Wiley Periodicals, Inc.     

P450 BM3 Monooxygenase as an Efficient NAD(P)H‐Oxidase for Regeneration of Nicotinamide Cofactors in ADH‐Catalysed Preparative Scale Biotransformations

Enzymatic oxidations of primary and secondary alcohols catalysed by nicotinamide dependent alcohol dehydrogenases on the preparative scale require cofactor regeneration systems. Of critical value from an economic and ecological perspective is the application of NAD(P)H‐oxidases, which utilise molecular oxygen as a cost‐effective, atom‐efficient and environmentally benign oxidant to regenerate the cofactor NAD(P)⁺. Herein, the P450 BM3 monooxygenase from Bacillus megaterium is presented as an NAD(P)H‐oxidase for the successful regeneration of both NADP⁺ and NAD⁺ on the preparative scale. This enzyme was exemplarily applied for ADH‐catalysed oxidative kinetic resolutions of racemic secondary alcohols and the desymmetrisation of a meso‐diol leading to enantiomerically enriched secondary alcohols in both cases. Furthermore, the ADH‐catalysed oxidation of a primary alcohol targeting the corresponding aldehyde was performed. The obtained results significantly broaden the scope of feasible oxidative biotransformations, thereby increasing the number of synthetic reactions complying with key challenges of a modern and sustainable chemistry such as mild reaction conditions, environmentally benign solvents, and biodegradable non‐toxic catalysts.

     

Effects of integrated fixed film activated sludge media on activated sludge settling in biological nutrient removal systems

Integrated fixed film activated sludge (IFAS) is an increasingly popular modification of conventional activated sludge, consisting of the addition of solid media to bioreactors to create hybrid attached/suspended growth systems. While the benefits of this technology for improvement of nitrification and other functions are well-demonstrated, little is known about its effects on biomass settleability. These effects were evaluated in parallel, independent wastewater treatment trains, with and without IFAS media, both at the pilot (at two solids residence times) and full scales. While all samples demonstrated good settleability, the Control (non-IFAS) systems consistently demonstrated small but significant (p < 0.05) improvements in settleability relative to the IFAS trains. Differences in biomass densities were identified as likely contributing factors, with Control suspended phase density > IFAS suspended phase density > IFAS attached phase (biofilm) density. Polyphosphate content (as non-soluble phosphorus) was well-correlated with density. This suggested that the attached phases had relatively low densities because of their lack of anaerobic/aerobic cycling and consequent low content of polyphosphate-accumulating organisms, and that differences in enhanced biological phosphorus removal performance between the IFAS and non-IFAS systems were likely related to the observed differences in density and settleability for the suspended phases. Decreases in solids retention times from 8 to 4 days resulted in improved settleability and increased density in all suspended phases, which was related to increased phosphorus content in the biomass, while no significant changes in density and phosphorus content were observed in attached phases.     

Polymer-Derived SiOC/ZrO2 Ceramic Nanocomposites with Excellent High-Temperature Stability

Polymer-derived SiOC/ZrO₂ ceramic nanocomposites have been prepared using two synthetic approaches. A commercially available polymethylsilsesquioxane (MK Belsil PMS) was filled with nanocrystalline zirconia particles in the first approach. The second method involved the addition of zirconium tetra( n -propoxide), Zr(OⁿPr)₄, as zirconia precursor to polysilsesquioxane. The prepared materials have been subsequently cross-linked and pyrolyzed at 1100°C in argon atmosphere to provide SiOC/ZrO₂ ceramics. The obtained SiOC/ZrO₂ materials were characterized by means of X-ray diffraction, elemental analysis, Raman spectroscopy as well as transmission electron microscopy. Furthermore, annealing experiments at temperatures from 1300° to 1600°C have been performed. The annealing experiments revealed that the incorporation of ZrO₂ into the SiOC matrix remarkably increases the thermal stability of the composites with respect to crystallization and decomposition at temperatures exceeding 1300°C. The results obtained within this study emphasize the enormous potential of polymer-derived SiOC/ZrO₂ composites for high-temperature applications.     

Cigarette Smoke Affects ABCAl Expression via Liver X Receptor Nuclear Translocation in Human Keratinocytes

Cutaneous tissue is the first barrier against outdoor insults. The outer most layer of the skin, the stratum corneum (SC), is formed by corneocytes embedded in a lipid matrix (cholesterol, ceramide and fatty acids). Therefore, the regulation of lipids and, in particular, of cholesterol homeostasis in the skin is of great importance. ABCA1 is a membrane transporter responsible for cholesterol efflux and plays a key role in maintaining cellular cholesterol levels. Among the many factors that have been associated with skin diseases, the environmental stressor cigarette smoke has been recently studied. In the present study, we demonstrate that ABCA1 expression in human cells (HaCaT) was increased (both mRNA and protein levels) after CS exposure. This effect was mediated by the inhibition of NFkB (aldehydes adducts formation) that allows the translocation of liver X receptor (LXR). These findings suggest that passive smoking may play a role in skin cholesterol levels and thus affect cutaneous tissues functions.     

Synthesis and Biological Testing of N‐Aminoimidazole‐Based p38α MAP Kinase Inhibitors

The p38 mitogen‐activated protein (MAP) kinase α plays a central role in the regulation of cellular responses such as differentiation, proliferation, apoptosis, and inflammation. Inhibition of p38 results in decreased synthesis of pro‐inflammatory cytokines. To date, diverse p38α inhibitors are in phase II clinical trials for numerous cytokine‐dependent diseases. 2‐Sulfanylimidazole derivatives offer advantages over the prototype inhibitor SB 203580, including fewer cytochrome P450 interactions and better kinetic properties. The aim of this study was to develop novel 1,2,4,5‐tetrasubstituted pyridinylimidazoles with acyl residues at the imidazole N1 position that can interact with the kinase's hydrophobic region II (HR II) or sugar pocket (SP) to improve both selectivity and activity. The substitution pattern was optimized by variation of the acyl moiety at the N1 position of the N‐aminoimidazole core. Acylation of the amino function was used for optimization and led to potent p38α MAPK inhibitors.     

Modeling and biological investigations of an unusual behavior of novel synthesized acridine-based polyamine ligands in the binding of double helix and G-quadruplex DNA

Three novel 2,7-substituted acridine derivatives were designed and synthesized to investigate the effect of this functionalization on their interaction with double-stranded and G-quadruplex DNA. Detailed investigations of their ability to bind both forms of DNA were carried out by using spectrophotometric, electrophoretic, and computational approaches. The ligands in this study are characterized by an open-chain (L1) or a macrocyclic (L2, L3) framework. The aliphatic amine groups in the macrocycles are joined by ethylene (L2) or propylene chains (L3). L1 behaved similarly to the lead compound m-AMSA, efficiently intercalating into dsDNA, but stabilizing G-quadruplex structures poorly, probably due to the modest stabilization effect exerted by its protonated polyamine chains. L2 and L3, containing small polyamine macrocyclic frameworks, are known to adopt a rather bent and rigid conformation; thus they are generally expected to be sterically impeded from recognizing dsDNA according to an intercalative binding mode. This was confirmed to be true for L3. Nevertheless, we show that L2 can give rise to efficient π-π and H-bonding interactions with dsDNA. Additionally, stacking interactions allowed L2 to stabilize the G-quadruplex structure: using the human telomeric sequence, we observed the preferential induction of tetrameric G-quadruplex forms. Thus, the presence of short ethylene spacers seems to be essential for obtaining a correct match between the binding sites of L2 and the nucleobases on both DNA forms investigated. Furthermore, current modeling methodologies, including docking and MD simulations and free energy calculations, provide structural evidence of an interaction mode for L2 that is different from that of L3; this could explain the unusual stabilizing ability of the ligands (L2>L3>L1) toward G-quadruplex that was observed in this study.     

Glutathione-S-transferase polymorphism, metallothionein expression, and mercury levels among students in Austria

BACKGROUND: Detoxification is an essential process in all living organisms. Humans accumulate heavy metals primarily as a result of lifestyle and environmental contamination. However, not all humans experience the estimated individual exposure. This suggests the presence of genetic regulatory mechanisms. OBJECTIVE: In order to identify genetic factors underlying the inter-individual variance in detoxification capacity for the heavy metal mercury, 192 students were investigated. We focused on the relationship between polymorphisms in glutathione-S-transferase (GST) genes and mercury concentrations in blood, urine, and hair. The correlation between blood mercury levels, GSTT1 and GSTM1 polymorphism, and gene expression of certain metallothionein subgroups (MT1, MT3) was evaluated in a further group of students (N=30). METHODS: Mercury levels in acid digested samples were measured by cold vapor AAS. Genotyping of the GSTT1 and GSTM1-gene deletion polymorphism was performed by means of PCR. Gene expression of several MT genes was analyzed in lymphocytes from fresh peripheral blood by semiquantitative RT-PCR. RESULTS: The following was noted: a) hair mercury concentrations are significantly increased in persons with the double deleted genotype (GSTT1-/- and GSTM1-/-) as compared to persons with the intact genotype, and b) MT1X expression is higher in persons with the intact genotype (GSTT1+/+ and GSTM1+/+). CONCLUSIONS: We conclude that the epistatic effect of the GSTT1 and the GSTM1 deletion polymorphism is a risk factor for increased susceptibility to mercury exposure. The relationship between MT gene expression and GST gene polymorphisms needs further investigation. If MT expression depends on GST polymorphisms it would have important implications on the overall metal detoxification capability of the human organism.