The Addressing Fragment of Mitogaligin: First Insights into Functional and Structural Properties

Mitogaligin is a mitochondrion‐targeting protein involved in cell death. The sequence of the protein is unrelated to that of any known pro‐ or antiapoptotic protein. Mitochondrial targeting is controlled by an internal sequence from residues 31 to 53, and although this sequence is essential and sufficient to provoke cell death, the precise mechanism of action at the mitochondrial membrane remains to be elucidated. Here, by focusing on the [31–53] fragment, we first assessed and confirmed its cell cytotoxicity by microinjection. Subsequently, with the aid of membrane models, we evaluated the impact of the membrane environment on the 3D structure of the peptide and on how the peptide is embedded and oriented within membranes. The fragment is well organized, even though it does not contain a canonical secondary structure, and adopts an interfacial location. Structural comparison with other membrane‐interacting Trp‐rich peptides demonstrated similarities with the antimicrobial peptide tritrpcidin.     

Quality of orange juice in barrier packaging material

The vitamin C content and the colour of orange juice made from concentrate were measured during 9 months of storage at 20°C either under artificial light or in darkness. The packaging materials used were glass, standard monolayer polyethylene terephthalate (PET) and multilayer PET (PET/nylon and oxygen scavenger/PET) containers. In this experiment, all bottles were sealed with aluminium foil in order to avoid any cap effect. The results showed that in plastic packaging materials, the loss of vitamin C was related to the oxygen permeability, and that glass provided the best preservation of ascorbic acid. No statistical difference (p < 0.05) was revealed between the vitamin C content in the juice stored under artificial light or in darkness, whatever the packaging used. The modification of colour was studied with the L, a* and b* values during storage at 20°C under artificial light. L and b* decreased, revealing a reduction of lightness and yellow colour of the juice, whereas a* increased, due to the formation of brown pigments. This change in colour was partly related to the oxygen permeability of the packaging used. The losses of aroma compounds by permeation through the bottle (PET) and the cap (high‐density polyethylene, HDPE) have also been investigated. The results showed that permeation mainly took place through the cap. The use of a multilayer cap [HDPE with internal barrier layer of low‐density polyethylene (LDPE)/EvOH/LDPE] considerably limited the permeation of the aroma compounds studied, whatever the PET bottle used. Copyright © 2007 John Wiley & Sons, Ltd.     

Domestic Water Consumption under Intermittent and Continuous Modes of Water Supply

Although an extensive literature emphasizes the disadvantages of intermittent water supply, it remains prevalent in rural areas of developing countries. Understanding the effects of water supply time restrictions on domestic water use activities and patterns, especially for hygienic purposes, is important for the elaboration of the water supply. We studied the influence of intermittent and continuous water supply on water consumption and related activities in villages in the central region of the Wei River basin, China. Data were collected from a survey of 225 households in the sampled villages. Compared with a continuous water supply of 24 h d^?1 (hours per day), adopting an intermittent water supply can reduce domestic water consumption. However, it presents risks in terms of hygiene behavior, particularly the frequency of face, hands, and feet washing, as well as water sharing among family members. Outdoor water consumption is more affected than indoor water consumption under slight supply restriction (≥6 and?<?24 h d^?1), whereas indoor water use is most affected under moderate supply restriction (>1.5 and?<?6 h d^?1). Villages with high supply restriction (≤1.5 h d^?1) meet only the minimum basic requirements for domestic use, 33.6–34.7 L c^?1 d^?1 (liters per capita per day). We conclude that the determination of the daily water delivery duration for intermittent water supply in rural communities of developing countries should give greater consideration to differences in water use activities and patterns under the water supply time restrictions.     

Food and packaging interactions: Use of methyl red as a probe for PVC swelling by fatty acid esters

A study of the interaction of fatty foods with rigid PVC packages was undertaken, using fatty acid esters CH₃(CH₂)_n−2COOR (8 ≤ n ≤ 18; R = Me, Et) as food simulants. Determination at 50°C of weight uptaken by PVC and of depth of penetration of the simulant into the material allowed us to define the time required to reach a thermodynamic equilibrium and the amount of liquid sorbed. Sorption at equilibrium decreased when chain length increased. When the simulant was tinted by methyl red, the dye adsorbed by the material was located exclusively in the diffusion layer. In contrast to sorption of the simulant, the absorbance of the dye in PVC went through a maximum for n = 14. Its spectrum depended on the extent of swelling of the polymer. In materials swollen by short-chain esters, the dye preferred a nonplanar conformation, stabilized through intermolecular solvatation by fatty acid esters. When solvatation and swelling were weak (n = 16, 18), the dye adopted a planar conformation, driven by intramolecular chelation, with a higher λ_max and a large extinction coefficient. Methyl red thus appeared as a probe for the study of interactions with slight swelling. © 1996 John Wiley & Sons, Inc.     

A novel mechanism-based mammalian cell assay for the identification of SH2-domain-specific protein-protein inhibitors

BACKGROUND: Many intracellular signal-transduction pathways are regulated by specific protein-protein interactions. These interactions are mediated by structural domains within signaling proteins that modulate a protein's cellular location, stability or activity. For example, Src-homology 2 (SH2) domains mediate protein-protein interactions through short contiguous amino acid motifs containing phosphotyrosine. As SH2 domains have been recognized as key regulatory molecules in a variety of cellular processes, they have become attractive drug targets. RESULTS: We have developed a novel mechanism-based cellular assay to monitor specific SH2-domain-dependent protein-protein interactions. The assay is based on a two-hybrid system adapted to function in mammalian cells where the SH2 domain ligand is phosphorylated, and binding to a specific SH2 domain can be induced and easily monitored. As examples, we have generated a series of mammalian cell lines that can be used to monitor SH2-domain-dependent activity of the signaling proteins ZAP-70 and Src. We are utilizing these cell lines to screen for immunosuppressive and anti-osteoclastic compounds, respectively, and demonstrate here the utility of this system for the identification of small-molecule, cell-permeant SH2 domain inhibitors. CONCLUSIONS: A mechanism-based mammalian cell assay has been developed to identify inhibitors of SH2-domain-dependent protein-protein interactions. Mechanism-based assays similar to that described here might have general use as screens for cell-permeant, nontoxic inhibitors of protein-protein interactions.     

Evaluation of hydroxyl terminated polybutadiene‐isophorone diisocyanate gel formation during crosslinking process

Crosslinking reaction of hydroxyl‐terminated polybutadiene (HTPB)/isophorone di‐isocyanate (IPDI) was monitored by infrared spectroscopy, dynamic mechanical analysis (DMA), swelling measurements, and by relaxation time (T₂) measurements obtained by low‐field NMR technique. Chemical reaction monitored by FTIR shows that urethane bonds were predominantly formed throughout the whole reaction period while DMA and swelling became only effective once the three‐dimensional network was formed. NMR results allow differentiating between relaxation‐processes associated with different fractions of the reactants in the mixture prior to the network formation. The most important finding in this study is that two of the relaxation processes were found to decline whereas a new fraction with a short relaxation time which emerged specifically at an early stage of reaction and progressed along with advancement of the reaction. All results pointed out to a change in the mixture behavior around 30 h of crosslinking reaction at 60°C, reflecting an important restriction in molecules diffusion and mobilities which were attributed to the gel point formation. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Replacing incandescent lamps with an LED panel for hydrogen production by photofermentation: Visible and NIR wavelength requirements

Hydrogen production by Rhodobacter capsulatus is a photobiological anaerobic process requiring light as energy source. In this study, the influence of visible and near-infrared (NIR) parts of light spectra from incandescent lamp and LED panels on hydrogen production was investigated. The results showed that the lack of the visible part of the incandescent lamp light spectrum (17% of the lamp light intensity) reduced hydrogen production by 50%. NIR wavelength only partially sustained photofermentation due to light limitation reached at low bacterial concentration. Hydrogen production with NIR light source was only 58% of hydrogen obtained with an incandescent lamp used at the same irradiance. To maximize hydrogen production and flow rate, visible and NIR wavelength should be used concomitantly as light source. Using an energy-efficient LED panel with light spectrum designed to promote photofermentation, hydrogen production and flow rate were equivalent to the ones reached with incandescent lamp as light source.     

Millimeter-wave propagation at street level in an urban environment

Measurements on point-to-point transmission at street level were performed in downtown Denver, CO, with RF probes that operated at 9.6, 28.8, and 57.6 GHz. All probes were mounted on self-contained vehicles, permitting a variety of path scenarios. Information on performance of these channels for propagation in an urban environment on both line-of-sight and non-line-of-sight paths is presented. For non-line-of-sight (non-LOS) paths obstructed by buildings of several common materials, results that showed signal attenuations in excess of 100 dB. When the LOS followed a path directly through clear glass walls, the attenuation was small at all probe frequencies. However, when the glass wall had a metalized coating to reduce ultraviolet and infrared radiation, the attenuation increased by 25 to 50 dB for each metallized layer. In most cases no signals could be detected through steel reinforced concrete or brick buildings     

Disruptions in Spatial Networks: a Comparative Study of Major Shocks Affecting Ports and Shipping Patterns

Networks and Spatial Economics - In this research, the effect of local exogenous shocks on seaports and maritime networks is assessed throughout three case-studies. The Hanshin-Awaji earthquake,...     

Formation of amylose complexes with C6-aroma compounds in starch dispersions and its impact on retention

Interactions between aroma compounds and starch matrices may increase the retention of aroma compounds. In particular, the linear amylose of starch, is able to form inclusion complexes with a wide variety of flavour compounds.