259 research outputs found
Ab initio/Rice–Ramsperger–Kassel–Marcus approach to carbon nitride formation: CH3NH2 decomposition
No full textCulture or social interaction? A study of influential factors on weblog design
No full textThe importance of blogs and social networking as medium of interactions had gain substantial popularity in mainstream media. Such popularity is due to blogs timely publication, ease of use and wide availability. Blogs hypertext and hyperlinks spread information and influence through an underlying social network. Taking into consideration that past studies on web design have focused on cultural traits on design elements, this paper aims to analyse the patterns on blog design from the perspectives of social influence and interactions. Examining design patterns from five networks of blogs using content analysis method, the results show that design of blogs in an online network shares similar elements and the pattern is different from one network to the other
Sar1p N-Terminal Helix Initiates Membrane Curvature and Completes the Fission of a COPII Vesicle
No full textSummarySecretory proteins traffic from the ER to the Golgi via COPII-coated transport vesicles. The five core COPII proteins (Sar1p, Sec23/24p, and Sec13/31p) act in concert to capture cargo proteins and sculpt the ER membrane into vesicles of defined geometry. The molecular details of how the coat proteins deform the lipid bilayer into vesicles are not known. Here we show that the small GTPase Sar1p directly initiates membrane curvature during vesicle biogenesis. Upon GTP binding by Sar1p, membrane insertion of the N-terminal amphipathic α helix deforms synthetic liposomes into narrow tubules. Replacement of bulky hydrophobic residues in the α helix with alanine yields Sar1p mutants that are unable to generate highly curved membranes and are defective in vesicle formation from native ER membranes despite normal recruitment of coat and cargo proteins. Thus, the initiation of vesicle budding by Sar1p couples the generation of membrane curvature with coat-protein assembly and cargo capture
CRISPR-mediated genome editing of Plasmodium falciparum malaria parasites
Get PDFThe development of the CRISPR-Cas system is revolutionizing genome editing in a variety of organisms. The system has now been used to manipulate the genome of Plasmodium falciparum, the most lethal malaria-causing species. The ability to generate gene deletions or nucleotide substitutions rapidly and economically promises to accelerate the analysis of novel drug targets and to help elucidate the function of specific genes or gene families, while complementing genome-wide association studies
Arresting malaria parasite egress from infected red blood cells
No full textThe escape of mature malaria parasites from the confines of their host red blood cells is an essential yet poorly understood process. Recent studies now highlight a key role for parasite proteases that trigger the degradation of parasite and host membranes, leading to the egress of infectious parasite forms.</p
Ceramide biosynthesis is required for the formation of the oligomeric H<sup>+</sup>-ATPase Pma1p in the yeast endoplasmic reticulum
No full textThe yeast plasma membrane H+-ATPase Pma1p is one of the most abundant proteins to traverse the secretory pathway. Newly synthesized Pma1p exits the endoplasmic reticulum (ER) via COPII-coated vesicles bound for the Golgi. Unlike most secreted proteins, efficient incorporation of Pma1p into COPII vesicles requires the Sec24p homolog Lst1p, suggesting a unique role for Lst1p in ER export. Vesicles formed with mixed Sec24p-Lst1p coats are larger than those with Sec24p alone. Here, we examined the relationship between Pma1p bio-synthesis and the requirement for this novel coat subunit. We show that Pma1p forms a large oligomeric complex of > 1 MDa in the ER, which is packaged into COPII vesicles. Furthermore, oligomerization of Pma1p is linked to membrane lipid composition; Pma1p is rendered monomeric in cells depleted of ceramide, suggesting that association with lipid rafts may influence oligomerization. Surprisingly, monomeric Pma1p present in ceramide-deficient membranes can be exported from the ER in COPII vesicles in a reaction that is stimulated by Lst1p. We suggest that Lst1p directly conveys Pma1p into a COPII vesicle and that the larger size of mixed Sec24pLst1p COPII vesicles is not essential to the packaging of large oligomeric complexes.</p
Molecular mechanisms of COPII vesicle formation
No full textThe first step in protein secretion from eukaryotic cells is mediated by COPII vesicles, known for the cytoplasmic coat proteins that are the minimal machinery required to generate these small transport carriers. The five COPII coat components coordinate to create a vesicle by locally generating membrane curvature and populating the incipient bud with the appropriate cargo. This review describes the molecular details of how the COPII coat sculpts vesicles from the endoplasmic reticulum and highlights some unresolved questions regarding the regulation of this process in the complex environment of the eukaryotic cell.</p
Evaluating the Ecological Impacts of Cultivating Genetically Modified Herbicide Tolerant (GMHT) Oilseed Rape and Maize: (2007-B-DS-1-S1) STRIVE Report
No full textThis report is published as part of the Science, Technology, Research and Innovation for the
Environment (STRIVE) Programme 2007–2013.Author has checked copyrigh
Antimicrobial surfaces based on self-assembled nanoreactors : from block copolymer synthesis to bacterial adhesion study
Get PDFThe aim of this work is to develop a new strategy for the prevention of biofilm growth. For this purpose, we prepared bioactive surfaces resulting from the surface-immobilization of nanoreactors self-assembled from amphiphilic poly(isobutylene)-block-oligonucleotide copolymers. The block copolymer was synthesized and characterized via appropriate complementary techniques. Self-assembly into vesicles allowed the functional encapsulation of enzymes, as assayed through enzyme activity monitoring, leading to a prodrug-drug system. The self-assembled structures were specifically immobilized on surfaces via base pairing between the oligonucleotide block of the copolymer and the surface tethered complementary nucleotide sequence.
Using E.coli strains, we first observed an influence of the two density of oligonucleotides immobilized on the surface on the number of adherent bacteria. This influence may be due to an effect of surface charge density. We then confirmed the well-known role of curli in biofilm cohesion, and we showed gene over-expression associated with curli production on oligonucleotide-modified surfaces. We demonstrated that gene over-expression does not depend on the topographical features of the surface or on the composition of the nucleotide sequences used in this study. Finally, we demonstrated that the presence of the vesicular structure is able to produce strong anti-adhesive properties of the surface. We assume, from observations of bacterial response in dynamic conditions, that this effect is due to increased bacterial motility on the surface, leading to a high detachment rate. Which is further confirms by a comparable bacterial response observed on agar hydrogel of different hardnesses. This result provides a preliminary outcome, paving the way to new approaches to antimicrobial strategies
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