57 research outputs found

    Logical gates in actin monomer

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    © 2017 The Author(s). We evaluate information processing capacity of a single actin molecule by calculating distributions of logical gates implemented by the molecule via propagating patterns of excitation. We represent a filamentous actin molecule as an excitable automaton network (F-actin automaton). where every atom updates its state depending on states of atoms its connected to with chemical bonds (hard neighbours) and atoms being in physical proximity to the atom (soft neighbours). A resting atom excites if a sum of its excited hard neighbours and a weighted sum of its soft neighbours belong to some specified interval. We demonstrate that F-actin automata implement OR, AND, XOR and AND-NOT gates via interacting patterns of excitation. Gate AND is the most common gate and gate XOR is the rarest. Using the architectures of gates discovered we implement one bit half-adder and controlled-not circuits in the F-actin automata. Speed and space values of the F-actin molecular computers are discussed

    Transient heterogeneity in extracellular protease production by Bacillus subtilis

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    The most sophisticated survival strategy Bacillus subtilis employs is the differentiation of a subpopulation of cells into highly resistant endospores. To examine the expression patterns of non-sporulating cells within heterogeneous populations, we used buoyant density centrifugation to separate vegetative cells from endospore-containing cells and compared the transcriptome profiles of both subpopulations. This demonstrated the differential expression of various regulons. Subsequent single-cell analyses using promoter-gfp fusions confirmed our microarray results. Surprisingly, only part of the vegetative subpopulation highly and transiently expresses genes encoding the extracellular proteases Bpr (bacillopeptidase) and AprE (subtilisin), both of which are under the control of the DegU transcriptional regulator. As these proteases and their degradation products freely diffuse within the liquid growth medium, all cells within the clonal population are expected to benefit from their activities, suggesting that B. subtilis employs cooperative or even altruistic behavior. To unravel the mechanisms by which protease production heterogeneity within the non-sporulating subpopulation is established, we performed a series of genetic experiments combined with mathematical modeling. Simulations with our model yield valuable insights into how population heterogeneity may arise by the relatively long and variable response times within the DegU autoactivating pathway

    A Human Monoclonal Antibody with Neutralizing Activity against Highly Divergent Influenza Subtypes

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    The interest in broad-range anti-influenza A monoclonal antibodies (mAbs) has recently been strengthened by theidentification of anti-hemagglutinin (HA) mAbs endowed with heterosubtypic neutralizing activity to be used in the designof ‘‘universal’’ prophylactic or therapeutic tools. However, the majority of the single mAbs described to date do not bindand neutralize viral isolates belonging to highly divergent subtypes clustering into the two different HA-based influenzaphylogenetic groups: the group 1 including, among others, subtypes H1, H2, H5 and H9 and the group 2 including, amongothers, H3 subtype. Here, we describe a human mAb, named PN-SIA28, capable of binding and neutralizing all testedisolates belonging to phylogenetic group 1, including H1N1, H2N2, H5N1 and H9N2 subtypes and several isolates belongingto group 2, including H3N2 isolates from the first period of the 1968 pandemic. Therefore, PN-SIA28 is capable ofneutralizing isolates belonging to subtypes responsible of all the reported pandemics, as well as other subtypes withpandemic potential. The region recognized by PN-SIA28 has been identified on the stem region of HA and includes residueshighly conserved among the different influenza subtypes. A deep characterization of PN-SIA28 features may represent auseful help in the improvement of available anti-influenza therapeutic strategies and can provide new tools for thedevelopment of universal vaccinal strategies

    IgE as Adjuvant in Tumor Vaccination

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    Activation of the antigen-IgE-Fc epsilon RI axis results in a potent inflammatory state. The redirection of this IgE-mediated activation of the immune system from allergic reactions toward tumors is the main theme of the new AllergoOncology field. Our particular approach has been to employ IgE as an adjuvant in anti-tumor vaccination. IgE-coated tumor cells can protect against tumor challenge, an observation that supports the involvement of IgE in anti-tumor immunity. The adjuvant effect of IgE was shown to result from eosinophil-dependent priming of the T-cell-mediated adaptive immune response. Moreover, the role of Fc epsilon RI in IgE anti-tumor adjuvanticity has been recently demonstrated. The interaction of tumor cell-bound IgE with receptors triggers the release of mediators with following recruitment of effector cells, cell killing and tumor antigen cross-priming. Starting from these evidences, several improvements toward a simple and universal use of IgE in anti-tumor cellular vaccines have been accomplished. In view of narrowing the gap between experimental models and therapeutic applications, the field is now shifting toward a humanized systems, employing human IgE and human Fc epsilon RI alpha transgenic mice

    Effect of some R factors on the sensitivity of rough Enterobacteriaceae to human serum

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    Effects of aminoglycoside antibiotics on neutrophil chemotaxis

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    The inhibitory effect of neutrophil chemotaxis of gentamicin, tobramycin, and sisomicin was shown. The combined effect of aminoglycosides and histamine was not additive
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