Superoxide radical production by sponges Sycon sp.

AbstractUsing the catechol Tiron as an O−⋅2 scavenger, we showed that sea sponges (Sycon sp.) produce superoxide radicals in sea water at a high rate without any stimuli added. The rate of O−⋅2 outflow from sponges to their water surroundings reaches a value of 0.5 nmol/min per sponge at pH 6.5. The generation of O−⋅2 was inhibited by Cu,Zn-superoxide dismutase, and restored by the addition of KCN. We also confirmed the abiotic production of O−⋅2 in sea water, detected earlier with a different method by Petasne and Zika [Nature 325 (1987) 516–518]

Single fluorescent protein-based Ca2+ sensors with increased dynamic range

<p>Abstract</p> <p>Background</p> <p>Genetically encoded sensors developed on the basis of green fluorescent protein (GFP)-like proteins are becoming more and more popular instruments for monitoring cellular analytes and enzyme activities in living cells and transgenic organisms. In particular, a number of Ca²⁺sensors have been developed, either based on FRET (Fluorescence Resonance Energy Transfer) changes between two GFP-mutants or on the change in fluorescence intensity of a single circularly permuted fluorescent protein (cpFP).</p> <p>Results</p> <p>Here we report significant progress on the development of the latter type of Ca²⁺sensors. Derived from the knowledge of previously reported cpFP-based sensors, we generated a set of cpFP-based indicators with different spectral properties and fluorescent responses to changes in Ca²⁺concentration. Two variants, named Case12 and Case16, were characterized by particular high brightness and superior dynamic range, up to 12-fold and 16.5-fold increase in green fluorescence between Ca²⁺-free and Ca²⁺-saturated forms. We demonstrated the high potential of these sensors on various examples, including monitoring of Ca²⁺response to a prolonged glutamate treatment in cortical neurons.</p> <p>Conclusion</p> <p>We believe that expanded dynamic range, high brightness and relatively high pH-stability should make Case12 and Case16 popular research tools both in scientific studies and high throughput screening assays.</p

Monitoring of Gene Expression in Bacteria during Infections Using an Adaptable Set of Bioluminescent, Fluorescent and Colorigenic Fusion Vectors

A family of versatile promoter-probe plasmids for gene expression analysis was developed based on a modular expression plasmid system (pZ). The vectors contain different replicons with exchangeable antibiotic cassettes to allow compatibility and expression analysis on a low-, midi- and high-copy number basis. Suicide vector variants also permit chromosomal integration of the reporter fusion and stable vector derivatives can be used for in vivo or in situ expression studies under non-selective conditions. Transcriptional and translational fusions to the reporter genes gfpmut3.1, amCyan, dsRed2, luxCDABE, phoA or lacZ can be constructed, and presence of identical multiple cloning sites in the vector system facilitates the interchange of promoters or reporter genes between the plasmids of the series. The promoter of the constitutively expressed gapA gene of Escherichia coli was included to obtain fluorescent and bioluminescent expression constructs. A combination of the plasmids allows simultaneous detection and gene expression analysis in individual bacteria, e.g. in bacterial communities or during mouse infections. To test our vector system, we analyzed and quantified expression of Yersinia pseudotuberculosis virulence genes under laboratory conditions, in association with cells and during the infection process

Temperature microsensor/microactuator based on magnetic microwire for MEMS applications

The aim of this paper has been the development of a new type of temperature microsensor/microactuator working on the principle of the thermo-elastic (TE) deformation of multilayer magnetic microwire consisting of a glass-coated CoSiB metallic core and an electroplated CoNi external shell. The application of an electrical current along the microwire in the range 20-35 mA results in the TE mechanical bending of fixed sample, which is recorded. That mechanical deformation is interpreted to be a consequence of the resulting Joule heating, and its amplitude is directly proportional to the applied dc current in the mentioned range. Moreover, the direct proportionality between TE deformation and the resulting increase of temperature was experimentally confirmed. In this way, the new type of temperature microsensor/microactuator working on the principle of TE deformation has been developed. This opens new technological application of microwires as temperature microsensors and temperature-driven microactuators for micro-electro-mechanical system devices

Electrical and optical properties of glasses based on TeO2- Sb2O3- PbCl2

International audienceThere were investigated optical transmittance and direct electrical conductivity of the glass systems of TeO2- Sb2O3-PbCl2. Optical transmittance measured in the wave range of (2.5 - 7.5) μm depends significantly on the amount and the nature of defects of glasses and the glass composition. The highest value of optical transmittance was found for glass of the composition of 40 TeO2- 10 Sb2O3 - 50 PbCl2. Direct electrical conductivity in the temperature range of (20 - 240) °C has the constant value of activation energy (∼1.1 eV) if glasses own the low concentration of PbCl2. If the concentration of PbCl2 is increased then the change of value of activation energy at the temperature ∼ 80°C was observed. The values of conductivity of the system TeO2- Sb2O3 -PbCl2 are strongly affected by the concentration of PbCl2

Określenie wydajności zastosowanego Schematu Wykopu Maszyną Drążącą

Deployment of a tunnel boring machine (TBM) for excavation of tunnel structures in particular rock mass environment requires to provide an efficient TBM advance rate by application of the proper excavation regime. The applied regime has to respond to the changes in the excavated rock mass and to the wear of cutting discs installed on the TBM cutterhead. The paper describes a method for the control of excavation efficiency using the excavation process variables monitored during the TBM operation, with subsequent calculation of specific cutting energy, contact pressure of cutting discs and theoretical torque of the TBM cutterhead.Rozmieszczenie Maszyny Drążącej (ang. TBM) do wykopu tuneli, w szczególności w przypadku masy skalnej, wymaga uzyskania wydajnego wykorzystania TBM poprzez zastosowanie odpowiedniego schematu wykopu. Użyty schemat powinien reagować na zmiany w masie skalnej i na zużycie tarczy tnących umieszczonych na głowicy skrawającej TBM. Artykuł opisuje sposoby kontrolowania wydajności wykopu poprzez sprawdzenie zmiennych wykopu obserwowanych podczas pracy TBM z późniejszymi wyliczeniami rozporządzalnej energii tnącej, nacisku tarcz tnących i teoretycznej wartości obrotu głowicy skrawającej TBM

Draft Genome Sequence of Blautia faecis Strain Marseille-P328, Isolated from the Human Ascending Colon.

International audienceBlautia faecis strain Marseille P328 was isolated from the ascending colon of a French patient. We sequenced the 4.45-Mb genome of the strain and compared itwith that of other species of the Blautia genus

Influence of NaI Additions on the Electrical, Dielectric, and Transport Properties in the GeS2-Ga2S3-NaI Glass System

International audienc