Effect of interferon γ on the sensitivity of bovine-papilloma-virus(BPV1)-transformed cell lines to cell-mediated cytotoxicity

Summary The effect of interferon (IFN) on the immunogenicity and immunosensitivity of mouse cell lines transformed by bovine papillomavirus type 1 (BPV1) DNA was examined in a syngeneic mouse model. The overnight incubation of BPV1-transformed cell lines with 100 IU/ml IFN did not affect their ability to induce the generation of cytotoxic effector cells but it clearly increased their sensitivity to lysis by interleukin-2-induced lymphokine-activated killer (LAK) cells and by nonspecific LAK-type effector cells induced by BPV-1-transformed cell lines. The treatment of two allogeneic lymphoid tumour cell lines, P815X2 and YAC-1, with IFN either decreased or had no effect on their sensitivity to LAK-cell-mediated lysis.     

Dissimilatory hexaheme c nitrite reductase of “Spirillum” strain 5175: purification and properties

When grown with nitrate as terminal electron acceptor both the soluble (periplasm, cytoplasm) and the membrane fraction of Spirillum strain 5175 exhibited high nitrite reductase activity. The nitrite reductase obtained from the soluble fraction was purified 76-fold to electrophoretical homogeneity. The enzyme reduced nitrite to ammonia with a specific activity of 723 mol NO _inf2 ^sup- × (mg protein × min)^-1. The molecular mass was 58±1 kDa by SDS-PAGE compared to 59±2 kDa determined by size exclusion chromatography under nondenaturing conditions. The enzyme (as isolated) contained 5.97±0.15 heme c molecules/M_r 58 kDa. The absorption spectrum was typical for c-type cytochrome with maxima at 280, 408, 532 and 610 nm (oxidized) and at 420, 523 and 553 nm (dithionite-reduced). The enzyme (as isolated) exhibited a complex set of high-spin and lowspin ferric heme resonances with g-values at 9.82, 3,85, 3.31, 2.95, 2.30 and 1.49 in agreement with data reported for electron paramagnetic resonance spectra of nitrite reductases from Desulfovibrio desulfuricans, Wolinella succinogenes and Escherichia coli.Abbreviations DNRA dissimilatory nitrate reduction to ammonia - EPR electron paramagnetic resonance - PAGE polyacrylamide gel electrophoresis - NaP_i sodium phosphate - SDS sodium dodecylsulfate     

Synthesis of alkyl fucosides through β-glucosidase-catalyzed condensation of fucose and 1-alcohols

-Glucosidase from almond catalyzed condensations of fucose and 1-alcohols with carbon numbers of 6 to 8 produce the corresponding 1-alkyl -d-fucosides. The enzyme also catalyzed the condensation of galactose and 1-hexanol. The conversion for the synthesis of hexyl fucoside was higher than those for the syntheses of hexyl glucoside and galactoside. The effect of initial saccharide concentrations on the conversions to alkyl glycosides was examined. The conversions at day 8 were almost the same at the low initial concentrations of the saccharides. However, the conversion significantly decreased as the concentrations increased. The surfactant properties of the prepared alkyl glycosides were measured. The critical micelle concentrations of the alkyl fucosides were lower than those of the glucosides and galactosides with the same alkyl chains.     

<Emphasis Type="Bold">Multi-disciplinary approach to changes in agro-pastoral activities since the Sub-Boreal in the surroundings of the “narse d’Espinasse” (Puy de Dôme,French Massif Central)</Emphasis>

The narse or peat marsh of Espinasse (Saulzet-le-Froid district) situated in the southern part of the Chaîne des Puys has been the subject of a new pollen analysis concentrating on the anthropogenic impact on vegetation evolution since the Sub-Boreal. Human occupation of the surroundings of the narse is dated as early as the Neolithic, which is usual for the region. There is nevertheless an isolated record of Fagopyrum related to the Neolithic. This is a unique occurrence in the Massif Central. For successive periods and up to the recent past, a dynamic of various anthropization phases has been reconstructed. The combination of palynological data with archaeological and historical sources has for certain periods, mainly from the 11^th to 13^th centuries, provided new insights on the social and technical management of the territory. Furthermore, geochemical and micromorphological characterisation of sedimentary organic matter has led to the identification of erosive crises and silting which would have followed massive tree cutting in the region. On the local scale, the highly degraded organic matter at the top of the peat profile is the consequence of the current drainage of the marsh.     

Amyloid-Beta Immunization in Alzheimer's Disease Transgenic Mouse Models and Wildtype Mice

Alzheimer's disease is the most prevalent form of dementia worldwide. Therapies are desperately needed to prevent and cure the disease. Mouse models of amyloid- deposition [APP and PSAPP transgenic (tg) mice] have been useful in determining the role of amyloid- (A) in both the pathogenesis and cognitive changes in AD. In addition, they have allowed scientists to investigate potential AD therapies in living animals. Active and passive A immunizations have been employed successfully in APP and PSAPP tg mice to lower cerebral A levels and improve cognition. Optimization of immunization protocols and characterization of immune responses in wildtype mice have been reported. Based on the promising results of A immunization studies in mice, a clinical trial was initiated for A vaccination in humans with AD. Although no adverse effects were reported in the Phase I safety trials, about 5% of AD patients in the phase II clinical trial developed meningoencephalitis, ending the trial prematurely in March 2002. Studies in AD mouse models and wildtype mice may help elucidate the mechanism for these unwanted side effects and will be useful for testing newer, safer vaccines for future use in human clinical trials.     

Rapid degradation of ferulic acid via 4-vinylguaiacol and vanillin by a newly isolated strain of bacillus coagulans

A new strain Bacillus coagulans BK07 was isolated from decomposed wood-bark, based on its ability to grow on ferulic acid as a sole carbon source. This strain rapidly decarboxylated ferulic acid to 4-vinylguaiacol, which was immediately converted to vanillin and then oxidized to vanillic acid. Vanillic acid was further demethylated to protocatechuic acid. Above 95% substrate degradation was obtained within 7 h of growth on ferulic acid medium, which is the shortest period of time reported to date. The major degradation products, was isolated and identified by thin-layer chromatography, high performance liquid chromatography and ¹H-nuclear magnetic resonance spectroscopy were 4-vinylguaiacol, vanillin, vanillic acid and protocatechuic acid.     

Triclosan susceptibility and co-metabolism--a comparison for three aerobic pollutant-degrading bacteria

The antimicrobial agent triclosan is an emerging and persistent environmental pollutant. This study evaluated the susceptibility and biodegradation potential of triclosan by three bacterial strains (Sphingomonas wittichii RW1, Burkholderia xenovorans LB400 and Sphingomonas sp. PH-07) that are able to degrade aromatic pollutants (dibenzofuran, biphenyl and diphenyl ether, respectively) with structural similarities to triclosan. These strains showed less susceptibility to triclosan when grown in complex and mineral salts media. Biodegradation experiments revealed that only strain PH-07 was able to catabolize triclosan to intermediates that included hydroxylated compounds (monohydroxy-triclosan, and dihydroxy-triclosan) and the ether bond cleavage products (4-chlorophenol and 2,4-dichlorophenol), indicating that the initial dihydroxylation occurred on both aromatic rings of triclosan. Additional growth inhibition tests demonstrated that the main intermediate, 2,4-dichlorophenol, was less toxic to strain PH-07 than was triclosan. Our results indicate that ether bond cleavage might be the primary mechanism of avoiding triclosan toxicity by this strain.     

Indirect carbon dioxide emissions from producing bioenergy from forest harvest residues

Forest harvest residues are important raw materials for bioenergy in regions practicing forestry. Removing these residues from a harvest site reduces the carbon stock of the forest compared with conventional stem‐only harvest because less litter in left on the site. The indirect carbon dioxide (CO₂) emission from producing bioenergy occur when carbon in the logging residues is emitted into the atmosphere at once through combustion, instead of being released little by little as a result of decomposition at the harvest sites. In this study (1) we introduce an approach to calculate this indirect emission from using logging residues for bioenergy production, and (2) estimate this emission at a typical target of harvest residue removal, i.e. boreal Norway spruce forest in Finland. The removal of stumps caused a larger indirect emission per unit of energy produced than the removal of branches because of a lower decomposition rate of the stumps. The indirect emission per unit of energy produced decreased with time since starting to collect the harvest residues as a result of decomposition at older harvest sites. During the 100 years of conducting this practice, the indirect emission from average‐sized branches (diameter 2 cm) decreased from 340 to 70 kg CO₂ eq. MWh^?1 and that from stumps (diameter 26 cm) from 340 to 160 kg CO₂ eq. MWh^?1. These emissions are an order of magnitude larger than the other emissions (collecting, transporting, etc.) from the bioenergy production chain. When the bioenergy production was started, the total emissions were comparable to fossil fuels. The practice had to be carried out for 22 (stumps) or four (branches) years until the total emissions dropped below the emissions of natural gas. Our results emphasize the importance of accounting for land‐use‐related indirect emissions to correctly estimate the efficiency of bioenergy in reducing CO₂ emission into the atmosphere.     

The electrooptical parameters of suspensions of <Emphasis Type="Italic">Escherichia coli</Emphasis> XL-1 cells interacting with helper phage M13K07

The electrophysical properties of Escherichia coli XL-1 cells interacting with helper phage M13K07 were studied as a function of the phage-to-cell ratio and the contact time. The electro-optical signal of bacterial cells changed considerably as soon as 10 min after the onset of their incubation with phage particles, presumably due to phage adsorption on the cell surface. The maximum changes in the orientational spectra of cell suspensions were observed when the phage-to-cell ratio was 20. Selectivity studies showed that E. coli XL-1 cells interacting with the helper phage M13K07 in the presence of foreign microflora, such as E. coli K-12 or Azospirillum brasilense Sp7, can be identified by using their electrophysical properties. Changes in the orientational spectra of cell suspensions are interpreted with the stage of phage-bacterium interaction taken into account. The results obtained can probably be used to devise a new rapid method for identification of microorganisms and to study the particular stages of cell infection by bacteriophages.__________Translated from Mikrobiologiya, Vol. 74, No. 2, 2005, pp. 198–203.Original Russian Text Copyright © 2005 by Bunin, Ignatov, Guliy, Zaitseva, ONeil, Ivnitskii     

Changes of enzyme activity in lipid signaling pathways related to substrate reordering

The static fluid mosaic model of biological membranes has been progressively complemented by a dynamic membrane model that includes phospholipid reordering in domains that are proposed to extend from nanometers to microns. Kinetic models for lipolytic enzymes have only been developed for homogeneous lipid phases. In this work, we develop a generalization of the well-known surface dilution kinetic theory to cases where, in a same lipid phase, both domain and nondomain phases coexist. Our model also allows understanding the changes in enzymatic activity due to a decrease of free substrate concentration when domains are induced by peptides. This lipid reordering and domain dynamics can affect the activity of lipolytic enzymes, and can provide a simple explanation for how basic peptides, with a strong direct interaction with acidic phospholipids (such as beta-amyloid peptide), may cause a complex modulation of the activities of many important enzymes in lipid signaling pathways.