22 research outputs found
Direct interaction between EgFABP1, a fatty acid binding protein from echinococcus granulosus, and phospholipid membranes
<p>Background: Growth and maintenance of hydatid cysts produced by Echinococcus granulosus have a high requirement for host lipids for biosynthetic processes, membrane building and possibly cellular and developmental signalling. This requires a high degree of lipid trafficking facilitated by lipid transporter proteins. Members of the fatty acid binding protein (FABP) family have been identified in Echinococcus granulosus, one of which, EgFABP1 is expressed at the tegumental level in the protoscoleces, but it has also been described in both hydatid cyst fluid and secretions of protoscoleces. In spite of a considerable amount of structural and biophysical information on the FABPs in general, their specific functions remain mysterious.</p>
<p>Methodology/Principal Findings: We have investigated the way in which EgFABP1 may interact with membranes using a variety of fluorescence-based techniques and artificial small unilamellar vesicles. We first found that bacterial recombinant EgFABP1 is loaded with fatty acids from the synthesising bacteria, and that fatty acid binding increases its resistance to proteinases, possibly due to subtle conformational changes induced on EgFABP1. By manipulating the composition of lipid vesicles and the ionic environment, we found that EgFABP1 interacts with membranes in a direct contact, collisional, manner to exchange ligand, involving both ionic and hydrophobic interactions. Moreover, we observed that the protein can compete with cytochrome c for association with the surface of small unilamellar vesicles (SUVs).</p>
<p>Conclusions/Significance: This work constitutes a first approach to the understanding of protein-membrane interactions of EgFABP1. The results suggest that this protein may be actively involved in the exchange and transport of fatty acids between different membranes and cellular compartments within the parasite.</p>
Coexistence of Paramagnetic-Charge-Ordered and Ferromagnetic-Metallic Phases in La0.5Ca0.5MnO3 evidenced by ESR
Throughout a complete Electron Spin Resonance (ESR) and magnetization study
of La0.5Ca0.5MnO3, we discuss about the nature of the complex phase-segregated
state established in this compound below T~210 K. Between TN<T<TC, the ESR
spectra shows two lines characteristic of two different magnetic phases. From
the resonance field (Hr) derived for each line we argue that the
incommensurate-charge-ordering phase (ICO) which coexists with
ferromagnetic-metallic (FMM) clusters in this temperature interval, is mainly
paramagnetic and not antiferromagnetic. The FMM/ICO ratio can be tuned with a
relatively small field, which suggests that the internal energy associated with
those phases is very similar. Below TN, there is an appreciable FM contribution
to the magnetization and the ESR spectra indicates the presence of FM clusters
in an antiferromagnetic matrix (canted). Our results show that ESR could be a
very useful tool to investigate the nature of the phase-separated state now
believed to play a fundamental role in the physics of mixed valent manganites.Comment: 6 pages, 6 figure
An Oral Recombinant Vaccine in Dogs against Echinococcus granulosus, the Causative Agent of Human Hydatid Disease: A Pilot Study
Dogs are the main source of human cystic echinococcosis. An oral vaccine would be an important contribution to control programs in endemic countries. We conducted two parallel experimental trials in Morocco and Tunisia of a new oral vaccine candidate against Echinococcus granulosus in 28 dogs. The vaccine was prepared using two recombinant proteins from adult worms, a tropomyosin (EgTrp) and a fibrillar protein similar to paramyosin (EgA31), cloned and expressed in a live attenuated strain of Salmonella enterica serovar typhimurium
On a theorem of Gulliksen on the homology of local rings
We show that a modification of the proof of a result of Gulliksen gives an
elementary proof of the following important theorem by Avramov: if is a homomorphism of noetherian local rings and is of finite flat
dimension over , then the homomorphism induced in Andr\'e-Quillen homology
modules is injective.Comment: 3 page
A nonenolizable imino-N-heterocyclic carbene ligand and corresponding silver(I) metal complex
The nonenolizable imino-N-heterocyclic carbene ligand precursor [1-t-butylimidazolium-3-{C(Ph)=N(Ph)}] chloride has been synthesised. The corresponding silver (I) complex Ag(C boolean AND imine)Cl; where C boolean AND imine=[1-t-butylimidazolium-2-ylidene-3-{C(Ph)=N(Ph)}], was prepared by reaction with Ag2O. All of the compounds have been structurally characterized by single crystal X-ray diffraction. (c) 2005 Elsevier B.V. All rights reserved