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showing 10 items of 1982 documents
Streaming for vehicular users via elastic proxy buffer management
2004
In this article we refer to the market of vehicular networks, where groups of customers located in the same public vehicle (e.g., a train or bus) connect to a terrestrial network through a wireless/satellite backbone link. Elastic buffering is a proxy management technique devised to decouple the multimedia information retrieval rate on the network backbone from the playout streaming rate at the user terminal. It has been shown in the past that the application of elastic buffering mechanisms in terrestrial networks brings significant advantages in terms of network effectiveness. We show that elastic buffering is an extremely effective means to reduce, or even eliminate, streaming service out…
Isolation and Characterization of Two Klebsiella pneumoniae Phages Encoding Divergent Depolymerases
2020
The emergence of multidrug-resistant bacteria is a major global health concern. The search for new therapies has brought bacteriophages into the spotlight, and new phages are being described as possible therapeutic agents. Among the bacteria that are most extensively resistant to current antibiotics is Klebsiella pneumoniae, whose hypervariable extracellular capsule makes treatment particularly difficult. Here, we describe two new K. pneumoniae phages, &pi
Size- and Structure-Selective Noncovalent Recognition of Saccharides by Tetraethyl and Tetraphenyl Resorcinarenes in the Gas Phase
2008
The noncovalent complexation of tetraethyl and tetraphenyl resorcinarenes with mono-, di-, and oligosaccharides was studied with negative-polarization electrospray ionization quadrupole ion trap and electrospray ionization Fourier-transform ion cyclotron resonance mass-spectrometric analysis. The saccharides formed 1:1 complexes with deprotonated resorcinarenes, which exhibited clear size and structure selectivity in their complexation. In the case of the monosaccharides, hexoses formed much more abundant and kinetically stable complexes than pentoses or deoxyhexoses. A comparison of the mono-, di-, and oligosaccharides revealed that both the relative abundance and stability of the complexe…
Confinement inside a Crystalline Sponge Induces Pyrrole To Form N−H⋅⋅⋅π Bonded Tetramers
2021
Based on the DFT‐level calculated molecular volume (V mol ) of pyrrole and its liquid density, pyrrole manifests the highest liquid density coefficient LD c (defined as [V mol • density • 0.6023]/FW) value of 0.7. Normal liquids have LD c < 0.63. This very high LD c is due to the strong N‐H … π interactions in solution and hence pyrrole can be considered to be a pseudo‐crystalline liquid. When trapped inside the confined space of the crystalline sponge a reorientation of the N‐H … π interaction is observed leading to specific cyclic N‐H … π tetramers and N‐H … π dimers, verified by single crystal X‐ray crystallographic and computational methods. These tetramers are of the same size as four …
Membrane Integration of Poliovirus 2B Viroporin
2011
Virus infections can result in a variety of cellular injuries, and these often involve the permeabilization of host membranes by viral proteins of the viroporin family. Prototypical viroporin 2B is responsible for the alterations in host cell membrane permeability that take place in enterovirus-infected cells. 2B protein can be localized at the endoplasmic reticulum (ER) and the Golgi complex, inducing membrane remodeling and the blockade of glycoprotein trafficking. These findings suggest that 2B has the potential to integrate into the ER membrane, but specific information regarding its biogenesis and mechanism of membrane insertion is lacking. Here, we report experimental results of in vi…
Itraconazole inhibits nuclear delivery of extracellular vesicle cargo by disrupting the entry of late endosomes into the nucleoplasmic reticulum
2021
ABSTRACT Extracellular vesicles (EVs) are mediators of intercellular communication under both healthy and pathological conditions, including the induction of pro‐metastatic traits, but it is not yet known how and where functional cargoes of EVs are delivered to their targets in host cell compartments. We have described that after endocytosis, EVs reach Rab7+ late endosomes and a fraction of these enter the nucleoplasmic reticulum and transport EV biomaterials to the host cell nucleoplasm. Their entry therein and docking to outer nuclear membrane occur through a tripartite complex formed by the proteins VAP‐A, ORP3 and Rab7 (VOR complex). Here, we report that the antifungal compound itracona…
Monoester copillar[5]arenes: synthesis, unusual self-inclusion behavior, and molecular recognition.
2012
The self-inclusion behavior of monoester copillar[5]arenes depends on the position of the ester group, which causes different guest selectivities. Monoester copillar[5]arenes bearing an acetate chain can form stable self-inclusion complexes in low- and high-concentration solution and exhibit high guest selectivity. However, a monoester copillar[5]arene bearing a butyrate chain can not form a self-inclusion complex and exhibits low guest selectivity. Thus, a new class of stable self-inclusion complexes of copillar[5]arenes was explored to improve the selectivity of molecular recognition.
Mediation of Elicitin Activity on Tobacco Is Assumed by Elicitin-Sterol Complexes
2001
Elicitins secreted by phytopathogenic Phytophthora spp. are proteinaceous elicitors of plant defense mechanisms and were demonstrated to load, carry, and transfer sterols between membranes. The link between elicitor and sterol-loading properties was assessed with the use of site-directed mutagenesis of the 47 and 87 cryptogein tyrosine residues, postulated to be involved in sterol binding. Mutated cryptogeins were tested for their ability to load sterols, bind to plasma membrane putative receptors, and trigger biological responses. For each mutated elicitin, the chemical characterization of the corresponding complexes with stigmasterol (1:1 stoichiometry) demonstrated their full functionali…
Mass Spectrometry and Structural Biology Techniques in the Studies on the Coronavirus-Receptor Interaction
2020
Mass spectrometry and some other biophysical methods, have made substantial contributions to the studies on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human proteins interactions. The most interesting feature of SARS-CoV-2 seems to be the structure of its spike (S) protein and its interaction with the human cell receptor. Mass spectrometry of spike S protein revealed how the glycoforms are distributed across the S protein surface. X-ray crystallography and cryo-electron microscopy made huge impact on the studies on the S protein and ACE2 receptor protein interaction, by elucidating the three-dimensional structures of these proteins and their conformational changes. The…
Proteome response of Tribolium castaneum larvae to Bacillus thuringiensis toxin producing strains.
2012
Susceptibility of Tribolium castaneum (Tc) larvae was determined against spore-crystal mixtures of five coleopteran specific and one lepidopteran specific Bacillus thuringiensis Cry toxin producing strains and those containing the structurally unrelated Cry3Ba and Cry23Aa/Cry37Aa proteins were found toxic (LC(50) values 13.53 and 6.30 µg spore-crystal mixture/µL flour disc, respectively). Using iTRAQ combined with LC-MS/MS allowed the discovery of seven novel differentially expressed proteins in early response of Tc larvae to the two active spore-crystal mixtures. Proteins showing a statistically significant change in treated larvae compared to non-intoxicated larvae fell into two major cat…