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See detailLipid-Destabilizing Properties Of The Hydrophobic Helices H8 And H9 From Colicin E1
Lins, Laurence ULg; El Kirat, K.; Charloteaux, Benoît ULg et al

in Molecular Membrane Biology (2007), 24(5-6), 419-30

Colicins are toxic proteins produced by Escherichia coli that must cross the membrane to exert their activity. The lipid insertion of their pf domain is linked to a conformational change which enables the ... [more ▼]

Colicins are toxic proteins produced by Escherichia coli that must cross the membrane to exert their activity. The lipid insertion of their pf domain is linked to a conformational change which enables the penetration of a hydrophobic hairpin. They provide useful models to more generally study insertion of proteins, channel formation and protein translocation in and across membranes. In this paper, we study the lipid-destabilizing properties of helices H8 and H9 forming the hydrophobic hairpin of colicin E1. Modelling analysis suggests that those fragments behave like tilted peptides. The latter are characterized by an asymmetric distribution of their hydrophobic residues when helical. They are able to interact with a hydrophobic/hydrophilic interface (such as a lipid membrane) and to destabilize the organized system into which they insert. Fluorescence techniques using labelled liposomes clearly show that H9, and H8 to a lesser extent, destabilize lipid particles, by inducing fusion and leakage. AFM assays clearly indicate that H8 and especially H9 induce membrane fragilization. Holes in the membrane are even observed in the presence of H9. This behaviour is close to what is seen with viral fusion peptides. Those results suggest that the peptides could be involved in the toroidal pore formation of colicin E1, notably by disturbing the lipids and facilitating the insertion of the other, more hydrophilic, helices that will form the pore. Since tilted, lipid-destabilizing fragments are also common to membrane proteins and to signal sequences, we suggest that tilted peptides should have an ubiquitous role in the mechanism of insertion of proteins into membranes. [less ▲]

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See detailLipid-Interacting Properties Of The N-Terminal Domain Of Human Apolipoprotein C-III
Lins, Laurence ULg; Flore, Christelle ULg; Chapelle, L. et al

in Protein Engineering (2002), 15(6), 513-20

The lipid-interacting properties of the N-terminal domain of human apolipoprotein C-III (apo C-III) were investigated. By molecular modeling, we predicted that the 6-20 fragment of apo C-III is obliquely ... [more ▼]

The lipid-interacting properties of the N-terminal domain of human apolipoprotein C-III (apo C-III) were investigated. By molecular modeling, we predicted that the 6-20 fragment of apo C-III is obliquely orientated at the lipid/water interface owing to an asymmetric distribution of the hydrophobic residues when helical. This is characteristic of 'tilted peptides' originally discovered in viral fusion proteins and later in various proteins including some involved in lipoprotein metabolism. Since most tilted peptides were shown to induce liposome fusion in vitro, the fusogenic capacity of the 6-20 fragment of apo C-III was tested on unilamellar liposomes and compared with the well characterized SIV fusion peptide. Mutants were designed by molecular modeling to assess the role of the hydrophobicity gradient in the fusion. FTIR spectroscopy confirmed the predominantly helical conformation of the peptides in TFE solution and also in lipid-peptide complexes. Lipid-mixing experiments showed that the apo C-III (6-20) peptide is able to increase the fluorescence of a lipophilic fluorescent probe. The vesicle fusion was confirmed by core-mixing and leakage assays. The hydrophobicity gradient plays a key role in the fusion process because the mutant with no hydrophobic asymmetry but the same mean hydrophobicity as the wild type does not induce significant lipid fusion. The apo C-III (6-20) fragment is, however, less fusogenic than the SIV peptide, in agreement with their respective mean hydrophobicity. Since lipid fusion should not be the physiological function of the N-terminal domain of apo CIII, we suggest that its peculiar distribution of hydrophobic residues is important for the lipid-binding properties of apo C-III and should be involved in apolipoprotein and lipid exchanges crucial for triglyceride metabolism. [less ▲]

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See detailLipid-lowering drug therapies and chronic obstructive pulmonary disease: lung failure or just heart failure?
Wierzbicki; Louis, Renaud ULg

in International journal of clinical practice (2014), 68(2), 144-51

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See detailLipides, dépression et suicide
Colin, A.; Reggers, Jean ULg; Castronovo, Vincenzo ULg et al

in Encéphale (L') (2003), 29(1, JAN-FEB), 49-58

Polyunsatured fatty acids are made out of a hydrocarbonated chain of variable length with several double bonds. The position of the first double bond (omega; omega) differentiates polyunsatured omega3 ... [more ▼]

Polyunsatured fatty acids are made out of a hydrocarbonated chain of variable length with several double bonds. The position of the first double bond (omega; omega) differentiates polyunsatured omega3 fatty acids (for example : alpha-linolenic acid or alpha-LNA) and polyunsatured omega6 fatty acids (for example : linoleic acid or LA). These two classes of fatty acids are said to be essential because they cannot be synthetised by the organism and have to be taken from alimentation. The omega3 are present in linseed oil, nuts, soya beans, wheat and cold water fish whereas omega6 are present in maize, sunflower and sesame oil. Fatty acids are part of phospholipids and, consequently, of all biological membranes. The membrane fluidity, of crucial importance for its functionning, depends on its lipidic components. Phospholipids composed of chains of polyunsatured fatty acids increase the membrane fluidity because, by bending some chains, double bonds prevent them from compacting themselves perfectly. Membrane fluidity is also determined by the phospholipids/free cholesterol ratio, as cholesterol increases membrane viscosity. A diet based on a high proportion of essential polyunsatured fatty acids (fluid) would allow a higher incorporation of cholesterol (rigid) in the membranes to balance their fluidity, which would contribute to lower blood cholesterol levels. Brain membranes have a very high content in essential polyunsatured fatty acids for which they depend on alimentation. Any dietary lack of essential polyunsatured fatty acids has consequences on cerebral development, modifying the activity of enzymes of the cerebral membranes and decreasing efficiency in learning tasks. Epidemiological data - The prevalence of depression seems to increase continuously since the beginning of the century. Though different factors most probably contribute to this evolution, it has been suggested that it could be related to an evolution of alimentary patterns in the Western world, in which polyunsatured omega fatty acids contained in fish, game and vegetables have been largely replaced by polyunsatured omega6 fatty acids of cereal oils. Some epidemiological data support the hypothesis of a relation between lower depression and/or suicide rates and a higher consumption of fish. These data do not however prove a relation of causality. Cholesterol and depression - Several cohort studies (on nondepressed subjects) have assessed the relationship between plasma cholesterol and depressive symptoms with contradictory results. Though some results found a significant relationship between a decrease of total cholesterol and high scores of depression, some other did not. Studies among patients suffering from major depression signalled more constantly an association between low cholesterol and major depression. Besides, some trials showed that clinical recovery maybe associated with a significant increase of total cholesterol. Cholesterol and suicidal behaviour - The hypothesis that a low cholesterol level may represent a suicidal risk factor was discovered accidentally following a series of epidemiological studies which revealed an increase of the suicidal risk among subjects with a low cholesterol level. Though some contradictory studies do exist, this relationship has been confirmed by several subsequent cohort studies. These findings have challenged the vast public health programs aimed at promoting the decrease of cholesterol, and even suggested to suspend the administration of lipid lowering drugs. Recent clinical studies on populations treated whith lipid lowering drugs showed nevertheless a lack of significant increase of mortality, either by suicide or accident. In addition, several controlled studies among psychiatric patients revealed a decrease of the concentrations of plasma cholesterol among patients who had attempted suicide in comparison with other patients. Polyunsaturated fatty acids and depression - In major depression, all studies revealed a significant decrease of the polyunsaturated omega3 fatty acids and/or an increase of the omega6/omega3 ratio in plasma and/or in the membranes of the red cells. In addition, two studies found a higher severity of depression when the level of polyunsaturated omega fatty acids or the ratio omega3/omega6 was low. Parallel to these modifications, other biochemical perturbations have been reported in major depression, particularly an activation of the inflammatory response system, resulting in an increase of the pro-inflammatory cytokines (interleukins: IL-1beta, IL-6 and interferon gamma) and eicosanoids (among others, prostaglandin E2) in the blood and the CSF of depressed patients. These substances cause a peroxidation and, consequently a catabolism of membrane phospholipids, among others those containing polyunsaturated fatty acids. The cytokines and eicosanoids derive from polyunsaturated fatty acids and have opposite physiological functions according to their omega or omega6 precursor. Arachidonic acid (omega6) is, among others, precursor of pro-inflammatoty prostaglandin E2 (PGE2), whereas polyunsaturated W fatty acids inhibit the formation of PGE2. It has been shown that a dietary increase of polyunsaturated W fatty acids reduced strongly the production of IL-1beta, IL-2, IL-6 and TNF-alpha (tumor necrosis factor-alpha). In contrast, diets with a higher supply of linoleic acid (omega6) increased significantly the production of pro-inflammatory cytokines, like TNF-alpha. Therefore, polyunsaturated omega3 fatty acids could be associated at different levels in the pathophysiology of major depression, on the one hand through their role in the membrane fluidity which influences diverse steps of neurotransmission and, on the other hand, through their function as precursor of pro-inflammatory cytokines and eicosanoids disturbing neurotransmission. In addition, antidepressants could exhibit an immunoregulating effect by reducing the release of pro-inflammatory cytokines, by increasing the release of endogenous antagonists of pro-inflammatory cytokines like IL-10 and, finally, by acting like inhibitors of cyclo-oxygenase. Therapeutic use of fatty acids - Data available concerning the administration of supplements of DHA (docosahexanoic acid) or other polyunsaturated fatty acids omega3 are limited. In a double blind placebo-controlled study on 30 patients with bipolar disorder, the addition of polyunsaturated omega3 fatty acids was associated with a longer period of remission. Moreover, nearly all the other prognosis measures were better in the omega3 group. Very recently, a controlled trial showed the benefits of adding an omega3 fatty acid, eicosopentanoic acid, among depressed patients. After 4 weeks, six of the 10 patients receiving the fatty acid were considered as responders in comparison with only one of the ten patients receiving placebo. Conclusions Some epidemiological, experimental and clinical data favour the hypothesis that polyunsaturated fatty acids could play a role in the pathogenesis and/or the treatment of depression. More studies however are needed in order to better precise the actual implication of those biochemical factors among the various aspects of depressive illness. [less ▲]

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See detailLipids composition of milk fat globule membrane extracted from cream
Bodson, Pascal; Danthine, Sabine ULg; Blecker, Christophe ULg

Poster (2004, September)

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See detailLipids metabolism and hyperlipidaemia in the dog
Jeusette, Isabelle; Istasse, Louis ULg; Diez, Marianne ULg

in Annales de Médecine Vétérinaire (2004), 148(2), 79-89

This synthesis aims to summarize lipids metabolism in the dog. The different aetiology and diagnostic of primary or secondary hyperlipidaemia in dog are reviewed. The nutritional treatment and more ... [more ▼]

This synthesis aims to summarize lipids metabolism in the dog. The different aetiology and diagnostic of primary or secondary hyperlipidaemia in dog are reviewed. The nutritional treatment and more particularly the use of dietary fibres are discussed. [less ▲]

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See detailLipids, risk factor in hemodialysed patients?
BOVY, Christophe ULg; Saint-Remy, Annie ULg; Juchmes, A. et al

in Nephrology Dialysis Transplantation (1998), 13

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See detailLipin-1 regulates cancer cell phenotype and is a potential target to potentiate rapamycin treatment
Brohée, Laura ULg; Demine, Stéphane; Willems, Jérôme ULg et al

in Oncotarget (2015), 6(13), 11264-11280

Lipogenesis inhibition was reported to induce apoptosis and repress proliferation of cancer cells while barely affecting normal cells. Lipins exhibit dual function as enzymes catalyzing the ... [more ▼]

Lipogenesis inhibition was reported to induce apoptosis and repress proliferation of cancer cells while barely affecting normal cells. Lipins exhibit dual function as enzymes catalyzing the dephosphorylation of phosphatidic acid to diacylglycerol and as co-transcriptional regulators. Thus, they are able to regulate lipid homeostasis at several nodal points. Here, we show that lipin-1 is up-regulated in several cancer cell lines and overexpressed in 50 % of high grade prostate cancers. The proliferation of prostate and breast cancer cells, but not of non-tumorigenic cells, was repressed upon lipin-1 knock-down. Lipin-1 depletion also decreased cancer cell migration through RhoA activation. Lipin-1 silencing did not significantly affect global lipid synthesis but enhanced the cellular concentration of phosphatidic acid. In parallel, autophagy was induced while AKT and ribosomal protein S6 phosphorylation were repressed. We also observed a compensatory regulation between lipin-1 and lipin-2 and demonstrated that their co-silencing aggravates the phenotype induced by lipin-1 silencing alone. Most interestingly, lipin-1 depletion or lipins inhibition with propranolol sensitized cancer cells to rapamycin. These data indicate that lipin-1 controls main cellular processes involved in cancer progression and that its targeting, alone or in combination with other treatments, could open new avenues in anticancer therapy. [less ▲]

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See detailLipodystrophy reactions to insulin: effects of continuous insulin infusion and new insulin analogs.
Radermecker, Régis ULg; Pierard, Gérald ULg; Scheen, André ULg

in American Journal of Clinical Dermatology (2007), 8(1), 21-8

Management of diabetes mellitus can be responsible for cutaneous adverse events. For example, lipoatrophy or lipohypertrophy can develop at the site of insulin injections. Lipohypertrophy remains a ... [more ▼]

Management of diabetes mellitus can be responsible for cutaneous adverse events. For example, lipoatrophy or lipohypertrophy can develop at the site of insulin injections. Lipohypertrophy remains a frequent complication of insulin therapy irrespective of the insulin source and mode of administration. Lipoatrophy at insulin injection sites is considered to be an immune complex-mediated inflammatory lesion; however, it has become a rare event since the advent of human insulin. Nowadays, continuous subcutaneous insulin infusion (CSII) using a portable pump and/or injections of insulin analogs with an altered amino acid sequence compared with native insulin may cause lipodystrophy in diabetic patients. Some case reports describe the recovery of lipoatrophy following the use of CSII and/or short-acting insulin analogs. Conversely, exceptional cases of lipoatrophy have occurred in patients receiving lispro insulin analog via CSII. Lipodystrophy reactions remain a potential problem when managing diabetic patients with new insulin therapy technologies. [less ▲]

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See detailLipofibromatous hamartoma of the median nerve. Three case reports.
Nardella, D; Sohawon, S; CARLIER, Alain ULg

in Journal of Plastic, Reconstructive and Aesthetic Surgery (2009), 62(9), 314-7

Nervous lipofibromatous hamartoma is a rare tumour-like condition involving the peripheral nerves, whereby the epineurium and perineurium are enlarged and distorted by excess fatty and fibrous tissues ... [more ▼]

Nervous lipofibromatous hamartoma is a rare tumour-like condition involving the peripheral nerves, whereby the epineurium and perineurium are enlarged and distorted by excess fatty and fibrous tissues that infiltrate between and around nerve boundaries. The median nerve is much more likely than other nerves to develop a hamartoma with a predilection for the carpal tunnel. In this article, we describe three cases of lipofibromatous hamartoma of the median nerve and discuss its management. [less ▲]

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See detailLipolyse electromagnetique et lipoatrophie semi-circulaire des cuisses
Flagothier, Caroline ULg; Quatresooz, Pascale ULg; Pierard, Gérald ULg

in Annales de Dermatologie et de Vénéréologie (2006), 133(6-7, Jun-Jul), 577-80

INTRODUCTION: The semicircular lipoatrophy of the thighs is a disorder whose incidence remained rare for years. Only recently, an "epidemic" situation emerged, affecting hundreds of subjects who shared a ... [more ▼]

INTRODUCTION: The semicircular lipoatrophy of the thighs is a disorder whose incidence remained rare for years. Only recently, an "epidemic" situation emerged, affecting hundreds of subjects who shared a status of administrative employee. OBSERVATION: The older etiopathogenic hypotheses give way to a newer one implying the electromagnetic fields generated by computers and their wirings. The resulting modifications in the intrinsic bioelectrical properties of the skin could influence the biology of macrophages exhibiting lipophagic activity in the hypodermis. The electroactivation of these cells could lead to TNF-alpha release. DISCUSSION: The semicircular lipoatrophy of the thighs is a problem that may affect an employee out of two. Rather than hoping an efficaceous drug therapy, prevention must be advocated by adapting the work conditions related to the use of computerized devices. [less ▲]

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See detailLipolysis inhibition by proteose-peptone : an interfaciale study.
Danthine, Sabine ULg; Blecker, Christophe ULg; Deroanne, Claude

Poster (2004, February 11)

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See detailLipomatose pelvienne associee a une cystite glandulaire: rapport de deux cas
Leruth, Elisabeth; Coppens, Luc ULg; Andrianne, Robert ULg et al

in Progrès en Urologie (2005), 15(1), 81-4

The authors report two cases of pelvic lipomatosis associated with glandular cystitis. This is a rare disease with variable and nonspecific clinical features. Complementary investigations useful for the ... [more ▼]

The authors report two cases of pelvic lipomatosis associated with glandular cystitis. This is a rare disease with variable and nonspecific clinical features. Complementary investigations useful for the diagnosis of pelvic lipomatosis are CT and especially MRI, intravenous urography and biopsies. The clinical features, radiological findings and therapeutic approach are discussed in the light of a review of the literature. [less ▲]

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See detailLipomatous hypertrophy of the interatrial septum: the typical echographic aspect is worth being known
ROYER, Ludovic ULg; HANS, Grégory ULg; CANIVET, Jean-Luc ULg et al

in Acta Anaesthesiologica Belgica (2011), 62(3), 157-159

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See detailLipopeptide production of Pseudomonas cichorii SF154 causing midrib rot on lettuce
Pauwelyn, E.; Ongena, Marc ULg; Hofte, M.

Conference (2011)

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See detailLipopeptides alter Bacillus subtilis hydrophobicity by adsorbing onto cell surfaces
Ahimou, François; Razafindralambo, Hary ULg; Paquot, Michel ULg

Poster (1997, October 29)

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See detailLipopeptides as main ingredients for inhibition of fungal phytopathogens by Bacillus subtilis/amyloliquefaciens
Cawoy, H.; Debois, Delphine ULg; Franzil, Laurent ULg et al

in Microbial Biotechnology (2015), 8(2), 281-295

Summary: Some isolates of the Bacillus subtilis/amyloliquefaciens species are known for their plant protective activity against fungal phytopathogens. It is notably due to their genetic potential to form ... [more ▼]

Summary: Some isolates of the Bacillus subtilis/amyloliquefaciens species are known for their plant protective activity against fungal phytopathogens. It is notably due to their genetic potential to form an impressive array of antibiotics including non-ribosomal lipopeptides (LPs). In the work presented here, we wanted to gain further insights into the relative role of these LPs in the global antifungal activity of B.subtilis/amyloliquefaciens. To that end, a comparative study was conducted involving multiple strains that were tested against four different phytopathogens. We combined various approaches to further exemplify that secretion of those LPs is a crucial trait in direct pathogen ward off and this can actually be generalized to all members of these species. Our data illustrate that for each LP family, the fungitoxic activity varies in function of the target species and that the production of iturins and fengycins is modulated by the presence of pathogens. Our data on the relative involvement of these LPs in the biocontrol activity and modulation of their production are discussed in the context of natural conditions in the rhizosphere. © 2014 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology. [less ▲]

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