Search results for "proteïnes"
showing 10 items of 89 documents
Structural and functional role of Domain I for the insecticidal activity of the Vip3Aa protein from Bacillus thuringiensis
2022
12 p.-4 fig.-2 tab.
Activation of Bacillus thuringiensis Cry1I to a 50 kDa stable core impairs its full toxicity to Ostrinia nubilalis
2021
Abstract Bacillus thuringiensis Cry1I insecticidal proteins are structurally similar to other three-domain Cry proteins, although their size, activity spectrum, and expression at the stationary phase are unique among other members of the Cry1 family. The mode of action of Cry1 proteins is not completely understood but the existence of an activation step prior to specific binding is widely accepted. In this study, we attempted to characterize and determine the importance of the activation process in the mode of action of Cry1I, as Cry1Ia protoxin or its partially processed form showed significantly higher toxicity to Ostrinia nubilalis than the fully processed protein either activated with …
Membrane insertion and topology of the p7B movement protein of Melon Necrotic Spot Virus (MNSV)
2007
AbstractCell-to-cell movement of the Melon Necrotic Spot Virus (MNSV) is controlled by two small proteins working in trans, an RNA-binding protein (p7A) and an integral membrane protein (p7B) separated by an amber stop codon. p7B contains a single hydrophobic region. Membrane integration of this region was observed when inserted into model proteins in the presence of microsomal membranes. Furthermore, we explored the topology and targeting mechanisms of full-length p7B. Here we present evidence that p7B integrates in vitro into the ER membrane cotranslationally and with an Nt-cytoplasmic/Ct-luminal orientation. The observed topology was monitored in vivo by fusing GFP to the Ct of p7B, enab…
Reduced membrane-bound alkaline phosphatase does not affect binding of Vip3Aa in a Heliothis virescens resistant colony
2020
The Vip3Aa insecticidal protein from Bacillus thuringiensis (Bt) is produced by specific transgenic corn and cotton varieties for efficient control of target lepidopteran pests. The main threat to this technology is the evolution of resistance in targeted insect pests and understanding the mechanistic basis of resistance is crucial to deploy the most appropriate strategies for resistance management. In this work, we tested whether alteration of membrane receptors in the insect midgut might explain the >
Plant virus cell-to-cell movement is not dependent on the transmembrane disposition of its movement protein
2009
ABSTRACT The cell-to-cell transport of plant viruses depends on one or more virus-encoded movement proteins (MPs). Some MPs are integral membrane proteins that interact with the membrane of the endoplasmic reticulum, but a detailed understanding of the interaction between MPs and biological membranes has been lacking. The cell-to-cell movement of the Prunus necrotic ringspot virus (PNRSV) is facilitated by a single MP of the 30K superfamily. Here, using a myriad of biochemical and biophysical approaches, we show that the PNRSV MP contains only one hydrophobic region (HR) that interacts with the membrane interface, as opposed to being a transmembrane protein. We also show that a proline resi…
Bacillus thuringiensis Toxins: Functional Characterization and Mechanism of Action
2020
Bacillus thuringiensis (Bt)-based products are the most successful microbial insecticides to date. This entomopathogenic bacterium produces different kinds of proteins whose specific toxicity has been shown against a wide range of insect orders, nematodes, mites, protozoa, and human cancer cells. Some of these proteins are accumulated in parasporal crystals during the sporulation phase (Cry and Cyt proteins), whereas other proteins are secreted in the vegetative phase of growth (Vip and Sip toxins). Currently, insecticidal proteins belonging to different groups (Cry and Vip3 proteins) are widely used to control insect pests and vectors both in formulated sprays and in transgenic crops (the …
Perlecan Maintains microvessel integrity in vivo and modulates their formation in vitro
2012
Perlecan is a heparan sulfate proteoglycan assembled into the vascular basement membranes (BMs) during vasculogenesis. In the present study we have investigated vessel formation in mice, teratomas and embryoid bodies (EBs) in the absence of perlecan. We found that perlecan was dispensable for blood vessel formation and maturation until embryonic day (E) 12.5. At later stages of development 40% of mutant embryos showed dilated microvessels in brain and skin, which ruptured and led to severe bleedings. Surprisingly, teratomas derived from perlecan-null ES cells showed efficient contribution of perlecan-deficient endothelial cells to an apparently normal tumor vasculature. However, in perlecan…
Palmitoylation of Pulmonary Surfactant Protein SP-C Is Critical for Its Functional Cooperation with SP-B to Sustain Compression/Expansion Dynamics in…
2010
AbstractRecent data suggest that a functional cooperation between surfactant proteins SP-B and SP-C may be required to sustain a proper compression-expansion dynamics in the presence of physiological proportions of cholesterol. SP-C is a dually palmitoylated polypeptide of 4.2 kDa, but the role of acylation in SP-C activity is not completely understood. In this work we have compared the behavior of native palmitoylated SP-C and recombinant nonpalmitoylated versions of SP-C produced in bacteria to get a detailed insight into the importance of the palmitic chains to optimize interfacial performance of cholesterol-containing surfactant films. We found that palmitoylation of SP-C is not essenti…
Effect of a traditional Mediterranean diet on apolipoproteins B, A-I, and their ratio: a randomized, controlled trial.
2011
Objectives: Apolipoprotein (Apo)B, ApoA-I, and their ratio could predict coronary heart disease (CHD) risk more accurately than conventional lipid measurements. Our aim was to assess the effect of a traditional Mediterranean diet (TMD) on apolipoproteins. Methods: High-cardiovascular risk subjects (n=551, 308 women and 243 men), aged 55-80 years, were recruited into a large, multicenter, randomized, controlled, parallel-group, clinical trial (The PREDIMED Study) aimed at testing the efficacy of TMD on primary cardiovascular disease prevention. Participants assigned to a low-fat diet (control) (n=177), or TMDs (TMD. +. virgin olive oil (VOO), n=181 or TMD. +. nuts, n=193) received nutritiona…
Hypertensive status and lipoprotein oxidation in an elderly population at high cardiovascular risk.
2008
BACKGROUND: In elderly individuals, hypertension is a main risk factor for cardiovascular disease and oxidative damage is increased. Our aim was to assess the relationship between the degree of in vivo low-density lipoprotein (oxLDL) oxidation and the hypertensive status in a elderly population at high cardiovascular risk. METHODS: Cross-sectional study with baseline data from the PREDIMED (PREvención con DIeta MEDiterránea) trial, an intervention study directed at testing the efficacy of the Mediterranean diet on the primary prevention of cardiovascular disease. Participants were 1,130 subjects at high cardiovascular risk aged 55-80. At baseline, in vivo circulating oxLDL was measured, and…