Characterization of a Bioactive Peptide T14 in the Human and Rodent Substantia Nigra: Implications for Neurodegenerative Disease

The substantia nigra is generally considered to show significant cell loss not only in Parkinson’s but also in Alzheimer’s disease, conditions that share several neuropathological traits. An interesting feature of this nucleus is that the pars compacta dopaminergic neurons contain acetylcholinesterase (AChE). Independent of its enzymatic role, this protein is released from pars reticulata dendrites, with effects that have been observed in vitro, ex vivo and in vivo. The part of the molecule responsible for these actions has been identified as a 14-mer peptide, T14, cleaved from the AChE C-terminus and acting at an allosteric site on alpha-7 nicotinic receptors, with consequences implicated in neurodegeneration. Here, we show that free T14 is co-localized with tyrosine hydroxylase in rodent pars compacta neurons. In brains with Alzheimer’s pathology, the T14 immunoreactivity in these neurons increases in density as their number decreases with the progression of the disease. To explore the functional implications of raised T14 levels in the substantia nigra, the effect of exogenous peptide on electrically evoked neuronal activation was tested in rat brain slices using optical imaging with a voltage-sensitive dye (Di-4-ANEPPS). A significant reduction in the activation response was observed; this was blocked by the cyclized variant of T14, NBP14. In contrast, no such effect of the peptide was seen in the striatum, a region lacking the T14 target, alpha-7 receptors. These findings add to the accumulating evidence that T14 is a key signaling molecule in neurodegenerative disorders and that its antagonist NBP14 has therapeutic potential.     

-1800 ps/(nm.km) chromatic dispersion at 1.55 μm in dualconcentric core fibre

A single-mode optical fibre exhibiting a very high negative chromatic dispersion (1800 ps/(nm.km)) at 1.5 μm is realised and characterised for dispersion compensation applications     

Flattening filter based on cascaded dual concentric core fibres

The use of dual concentric core fibres to realise a flattening filter is reported. The power spectrum of an ASE source has been flattened in the C-band from 5.8 to 1.4 dB.     

Fatty acid composition of seed oils from sixAdansonia species with particular reference to cyclopropane and cyclopropene acids

The oil content of sixAdansonia species (Bombacaceae family) of Madagascar (Adansonia grandidieri, A. za, A. digitata, A. fony, A. madagascariensis andA. suarenzensis) and Africa (A. digitata) ranges from 8 to 46%. All the oils give a positive response to the Halphen test. Malvalic, sterculic and dihydrosterculic acids were detected using gas liquid chromatography-mass spectrometry (GLC-MS). Epoxy or hydroxy fatty acids were not found in these oils. Fatty acid composition was determined by GLC using glass capillary columns coated with BDS and Carbowax 20 M. Results obtained for cyclopropenic fatty acids (CPEFA) were compared to those given by glass capillary GLC after derivatization with silver nitrate in methanol, by hydrogen bromide titration and by proton magnetic resonance (PMR). Good agreement was observed for the results given by the various methods. Malvalic acid content ranges from 3 to 28%, sterculic acid from 1 to 8% and dihydrosterculic acid from 1.5 to 5.1%. Odd-numbered fatty acids (Pentadecanoic and hepatadecanoic) were also observed in minute amounts (0.1–1.1%). Among the normal fatty acids, we observed mainly palmitic (21–46%), oleic (15–40%) and linoleic (12–32%). The relationship between fatty acid composition andAdansonia species is discussed.     

Proteomics analysis of liver pathological calcification suggests a role for the IQ motif containing GTPase activating protein 1 in myofibroblast function

To date the cellular and molecular mechanisms by which liver pathological calcifications occur and are regulated are poorly investigated. To study the mechanisms linked to their appearance, we performed a proteomics analysis of calcified liver samples. To this end, human liver biopsies collected in noncalcified (N), precalcified (P), and calcified (C) areas of the liver were subjected to weak ion exchange chromatography, SDS‐PAGE, and LC‐ESI MS/MS analyses. As we previously demonstrated that alpha‐smooth muscle actin (α‐SMA) expressing myofibroblasts were involved in liver pathological calcification, we performed a targeted analysis of actin cytoskeleton remodeling‐related proteins. This revealed dramatic changes in protein expression patterns in the periphery of the calcified areas. More particularly, we found that IQGAP1 and IQGAP2 proteins were subjected to major expression changes. We show that IQGAP1 expression within P and C areas of the liver correlates with the high abundance of myofibroblasts and that IQGAP1 is specifically expressed in these cells. In addition, we find that IQGAP1 is part of a protein complex including β‐catenin and Rac1 mainly in P and C regions of the liver. These results suggest that IQGAP1 may play a critical role in the regulation of cytoskeleton remodeling in liver myofibroblasts in response to liver injury and consequently impact on their function.     

Monolayers and mixed-layers on copper towards corrosion protection

In order to improve the protection abilities of (3-mercaptopropy)trimethoxysilane (MPTS) self-assembled monolayers on copper surfaces, mixed monolayers have been formed successfully by successive immersions in MPTS and in n-dodecanethiol (DT). A newly synthesised molecule, (11-mercaptoundecyl)trimethoxysilane (MUTS), has also been employed to form a thicker organic film on copper surfaces and, thereby, enhance the inhibitory action of the coating. The grafting has been confirmed by X-ray photoelectron spectroscopy (XPS), polarization modulation infrared reflection adsorption spectroscopy (PM-IRRAS) and water contact angle. The protective efficiency of each protective organic film has been evidenced by cyclic voltammetry (CV) and polarization curve measurements (CP). It was shown that the MUTS and unhydrolyzed MPTS/DT films exhibited significant corrosion protection properties.     

Assessment of the bacteriological quality and nitrate pollution risk of Quaternary groundwater in the southern part of Abidjan District (Côte d’Ivoire)

In this study, total coliforms, thermotolerant coliforms, Escherichia coli and groundwater nitrate concentration were monitored at 127 groundwater sampling points (only 62 water points for bacteriological parameters) located in the southern part of Abidjan District. Each water sampling location was sampled in March and July 2007, representing respectively the long dry season and the long wet season. Geostatistical methods were used to analyze the spatial variability of nitrates and the groundwater nitrate pollution risk. The maximum seasonal content of total coliforms and thermotolerant coliforms ranged from 400 to 1000 CFU/100 mL and from 200 to 500 CFU/100 mL respectively. Moreover, 94% of these locations presented traces of bacteriological contamination. This contamination was mainly recorded during the rainy period. The degree of correlation between bacterial abundance and chemical parameters is variable. Nitrites, ammonium and potassium favoured coliform abundance. In the 127 water points, groundwater nitrate concentrations ranged from 4 to 198 mg L^?1 and were log-normally distributed in the study area. The groundwater contamination risk map indicated that the strongly urbanized west side of the site presented a high probability of exceeding the WHO drinking water standard (50 mg L^?1NO₃^?).