The immunosuppressive substance 2-chloro-2-deoxyadenosine modulates lipoprotein metabolism in a murine macrophage cell line (P388 cells)

A recently developed immunosuppressive substance, 2-chloro-2-deoxyadenosine (2-CdA), was reported to inhibit monocyte functions at low concentration. Because macrophages play a key role in the formation of atherosclerotic plaques, it was of interest to study the effect of 2-CdA on cellular lipid metabolism. For this purpose we have used a macrophage cell line (P388) to perform incubation studies in the presence of acetylated low density lipoprotein (Ac-LDL) and 2-CdA. The addition of 2-CdA, in concentrations ranging from 5–20 nM, induced a dose-dependent decrease in cellular cholesterol content and in the amount of extracellular [¹⁴C]oleic acid (OA) incorporated into the cholesteryl ester (CE) fraction. The effect was maximized at 20 nM 2-CdA with an 86% reduction in cholesterol esterification compared to controls (P<0.008). To evaluate the mechanism of interaction of 2-CdA with cellular lipid metabolism, deoxycytidine (dCyt) and 3-methoxybenzamide (3-MOB), substances known to antagonize the effect of 2-CdA in different ways, were co-administered with 2-CdA. dCyt, a competitive inhibitor of dCyt kinase, which catalyzes phosphorylation to the active metabolite, antagonized the effects of 20 nM 2-CdA, producing significantly greater incorporation of extracellular [¹⁴C]OA into the CE fraction than in the presence of 2-CdA alone (P<0.0086). Co-incubation with 2-CdA and the poly-ADP-ribose synthetase inhibitor 3-MOB, which is known to render cells resistant to 2-CdA toxicity by preventing cellular nicotinamide adenine dinucleotide (NAD)- and adenosine triphosphase-depletion, also reversed the effect of 2-CdA on lipid accumulation. However, incubation of P388 cells with 20 nM 2-CdA did not result in a decrease in cellular NAD content. As 20 nM 2-CdA showed no effect on intracellular cholesterol synthesis based on measurement by 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, the decrease in cellular cholesterol content and in [¹⁴C]OA incorporation seems to be primarily due to an interference with Ac-LDL metabolism.     

XIV. Yeast sequencing reports. A 21·7 kb DNA segment on the left arm of yeast chromosome XIV carries WHI3, GCR2, SPX18, SPX19, an homologue to the heat shock gene SSB1 and 8 new open reading frames of unknown function

We report the amino acid sequence of 13 open reading frames (ORF > 299 bp) located on a 21·7 kb DNA segment from the left arm of chromosome XIV of Saccharomyces cerevisiae. Five open reading frames had been entirely or partially sequenced previously: WHI3, GCR2, SPX19, SPX18 and a heat shock gene similar to SSB1. The products of 8 other ORFs are new putative proteins among which N1394 is probably a membrane protein. N1346 contains a leucine zipper pattern and the corresponding ORF presents an HAP (global regulator of respiratory genes) upstream activating sequence in the promoting region. N1386 shares homologies with the DNA structure-specific recognition protein family SSRPs and the corresponding ORF is preceded by an MCB (MluI cell cycle box) upstream activating factor. The sequence has been deposited in the EMBL data library under Accession Number X78898.     

Acute On‐Chip HIV Detection Through Label‐Free Electrical Sensing of Viral Nano‐Lysate

Development of portable biosensors has broad applications in environmental monitoring, clinical diagnosis, public health, and homeland security. There is an unmet need for pathogen detection at the point‐of‐care (POC) using a fast, sensitive, inexpensive, and easy‐to‐use method that does not require complex infrastructure and well‐trained technicians. For instance, detection of Human Immunodeficiency Virus (HIV‐1) at acute infection stage has been challenging, since current antibody‐based POC technologies are not effective due to low concentration of antibodies. In this study, we demonstrated for the first time a label‐free electrical sensing method that can detect lysed viruses, i.e. viral nano‐lysate, through impedance analysis, offering an alternative technology to the antibody‐based methods such as dipsticks and Enzyme‐linked Immunosorbent Assay (ELISA). The presented method is a broadly applicable platform technology that can potentially be adapted to detect multiple pathogens utilizing impedance spectroscopy for other infectious diseases including herpes, influenza, hepatitis, pox, malaria, and tuberculosis. The presented method offers a rapid and portable tool that can be used as a detection technology at the POC in resource‐constrained settings, as well as hospital and primary care settings.     

Behavioral and physiological responses to maternal separation in squirrel monkeys (Saimiri sciureus).

This study extends an examination of the behavioral and pituitary-adrenal responses of infant squirrel monkeys (Saimiri sciureus) separated from their mothers under different environmental conditions to another physiological system by measuring the metabolites of the central monoamines found in the cerebrospinal fluid (CSF). This study included spectrographic examination of the vocalizations emitted by the infant during separation. Infants were separated from their mothers for 24 hr under 3 conditions: Home, infant remained in his home cage after removal of mother; adjacent, infant was placed in a cage adjacent to its mother; and total, infant was totally isolated. The behavioral results indicated that the number of calls emitted differed with condition (adjacent?>?total?>?home), and the peak frequency of the calls and number of multiple calls was greatest in the total condition. Plasma cortisol elevations after separation differentiated the conditions of separation (total?>?adjacent?>?home?>?base). The elevations in the CSF catecholamine metabolites (3-methoxy-4-hydroxyphenylglycol and homovanillic acid) were also sensitive to the conditions of separation (total?>?adjacent?>?base). These results are discussed in the context of coping theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic transformation of Brevibacterium linens strains producing high amounts of diverse sulphur compounds

By its numerous properties and importance in cheese technology (production of colour, flavour, bacteriocins and resistance to salt) Brevibacterium linens is a major cheese ripening bacteria. However, the genetic approach of such biological functions has been hindered, up to now, by the lack of tools necessary to realise genetic modifications in this species. Our objective was to demonstrate that it is possible to genetically modify several strains exhibiting interesting technological properties, especially the production of sulphur compounds. We worked with a phenotypically and genetically diverse collection of 11 strains. We genetically transformed several Brevi. linens with acceptable rates with plasmids classically used to transform lactic acid bacteria and other Gram+ bacteria. These results open up new prospects to investigate the most interesting Brevi. linens metabolic pathways both at the biochemical and genetic level.     

Compatibilising action of random and triblock copolymers of poly(styrene-butadiene) in polystyrene/polybutadiene blends: A study by electron microscopy, solid state NMR spectroscopy and mechanical measurements

Scanning electron microscopy, solid-state proton NMR spectroscopy and static mechanical analysis have been performed in order to evaluate the compatibilising action of random copolymers of polystyrene and polybutadiene and triblock copolymers of poly(styrene-butadiene-styrene) in incompatible polystyrene/polybutadiene (PS/PB) blends. Scanning electron microscopic examination of the cryofractured and etched surfaces showed high degree of compatibilising action of the triblock copolymers as evidenced by the very sharp decrease of the domain size of the dispersed phase followed by an increase at higher concentrations. This is a clear indication of interfacial saturation. These results were in agreement with the theoretical predictions of Noolandi and Hong. The random copolymer was not effective in compatibilising the system. Solid-state proton NMR experiments were performed on the uncompatibilised and compatibilised blends. The proton spin-lattice relaxation times in the laboratory frame, T₁(H), and in the rotating frame, T_1ρ(H), and spin-spin relaxation times, T₂(H), were carefully measured for the systems. Significant changes were observed for the systems compatibilised with triblock copolymers due to the preferential localisation of the copolymers at the PS/PB interface. However, the random copolymer did not have any compositional drift and is not an effective interface modifier in agreement with microscopy study. The static mechanical properties of the blends have also been analysed. The addition of triblock copolymers increased the mechanical properties of the blends. Finally, attempts have been made to correlate the NMR results with the microstructure and mechanical properties of the blends.     

Intra- and interlaboratory reproducibility of ultra performance liquid chromatography-time-of-flight mass spectrometry for urinary metabolic profiling

Liquid chromatography coupled to mass spectrometry (LC-MS) is a major platform in metabolic profiling but has not yet been comprehensively assessed as to its repeatability and reproducibility across multiple spectrometers and laboratories. Here we report results of a large interlaboratory reproducibility study of ultra performance (UP) LC-MS of human urine. A total of 14 stable isotope labeled standard compounds were spiked into a pooled human urine sample, which was subject to a 2- to 16-fold dilution series and run by UPLC coupled to time-of-flight MS at three different laboratories all using the same platform. In each lab, identical samples were run in two phases, separated by at least 1 week, to assess between-day reproducibility. Overall, platform reproducibility was good with median mass accuracies below 12 ppm, median retention time drifts of less than 0.73 s and coefficients of variation of intensity of less than 18% across laboratories and ionization modes. We found that the intensity response was highly linear within each run, with a median R(2) of 0.95 and 0.93 in positive and negative ionization modes. Between-day reproducibility was also high with a mean R(2) of 0.93 for a linear relationship between the intensities of ions recorded in the two phases across the laboratories and modes. Most importantly, between-lab reproducibility was excellent with median R(2) values of 0.96 and 0.98 for positive and negative ionization modes, respectively, across all pairs of laboratories. Interestingly, the three laboratories observed different amounts of adduct formation, but this did not appear to be related to reproducibility observed in each laboratory. These studies show that UPLC-MS is fit for the purpose of targeted urinary metabolite analysis but that care must be taken to optimize laboratory systems for quantitative detection due to variable adduct formation over many compound classes.     

Investigation of the polyurethane chain length influence on the molecular dynamics in networks crosslinked by hyperbranched polyester

Several non-conventional polyurethane (PU) networks crosslinked with hyperbranched polyester (Boltorn^®H40) were synthesised with an aim to determine an influence of the PU chain length on molecular relaxations in such systems. The PU chain length was regulated by changing the macrodiol length or by changing the number of the repeating macrodiol/diisocyanate units n. Molecular dynamics were investigated by broadband dielectric spectroscopy and by dynamic mechanical analysis. It was found that the macrodiol length has a strong influence on the glass transition and the α-relaxation, and also on the crystallization. By contrast, the changes of n practically do not affect the molecular relaxations. This effect was explained by the formation of a physical network by hydrogen bonds between urethane groups, controlling the molecular mobility. The rheological measurements have shown, that at temperatures above 150 °C, when hydrogen bonds were thermally destroyed, not only macrodiol length but also n had strong influence on the flowing point.     

Design and Performance Analysis of Objective Functions for RPL Routing Protocol

Wireless Personal Communications - Standardized by Internet Engineering Task Force (IETF) working group, RPL (Routing Protocol for Low Power and Lossy networks) stands as an effective IPV6 Routing...     

Role of Na2CO3 on an AISI 330 austenitic stainless steels oxidation at 900°C

This study shows the influence of sodium carbonate coatings on the austenitic AISI 330 (Fe–35Ni–19Cr–1.3Si) oxidized during 48 hr at 900°C. The N₂‐5 vol% H₂ gaseous environment was used to simulate industrial heat treatment conditions. Silica scale formation is promoted by low oxygen‐containing gaseous environments and the high alloy silicon content. On this alloy, an amorphous silica scale is formed after the blank material oxidation. It indicates that silicon is free to diffuse in the alloy and forms a silica scale at the internal interface. On Na₂CO₃‐coated specimens, no silica scale is formed. Then, sodium combines with silicon to form amorphous glass particles. A comparison has been performed with results obtained on a AISI 330Cb niobium containing alloy in the same oxidizing conditions. It is then concluded that sodium carbonate coatings could only favor silica formation on niobium containing alloy due to a reaction between sodium and niobium.