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Membrane Sterols

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https://www.readbyqxmd.com/read/28646165/selective-inhibition-of-sterolo-acyltransferase-1-isozyme-by-beauveriolide-iii-in-intact-cells
#1
Taichi Ohshiro, Keisuke Kobayashi, Mio Ohba, Daisuke Matsuda, Lawrence L Rudel, Takashi Takahashi, Takayuki Doi, Hiroshi Tomoda
Beauveriolide III (BeauIII) inhibited sterol O-acyltransferases 1 and 2 (SOAT1 and SOAT2), which are endoplasmic reticulum (ER) membrane proteins, in an enzyme-based assay, and selectively inhibited SOAT1 in a cell-based assay using SOAT1-/SOAT2-CHO cells. This discrepancy in SOAT inhibition by BeauIII was investigated. In the enzyme-based assay, BeauIII inhibited SOAT1 and SOAT2 to a similar extent using microsomes prepared from cells disrupted under the strongest sonication condition. In semi-intact SOAT1-/SOAT2-CHO cells prepared by a treatment with digitonin (plasma membrane permeabilized), BeauIII selectively inhibited SOAT1 (IC50; 5...
June 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28642044/crossregulation-between-the-insertion-of-hexadecylphosphocholine-miltefosine-into-lipid-membranes-and-their-rheology-and-lateral-structure
#2
Yenisleidy de Las Mercedes Zulueta Díaz, María Laura Fanani
Hexadecylphosphocholine (HePC, miltefosine) is an alkylphospholipid used clinically for the topical treatment of cancer and against leishmaniasis. The mechanism of action of HePC, not yet elucidated, involves its insertion into the plasma membrane, affecting lipid homeostasis. It has also been proposed that HePC directly affects lipid raft stability and function in cell membranes. The present work deals with two main questions in the understanding of the action of HePC: the bases for membrane selectivity and as a membrane perturbator agent...
June 19, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28640190/trans-cinnamic-and-chlorogenic-acids-affect-the-secondary-metabolic-profiles-and-ergosterol-biosynthesis-by-fusarium-culmorum-and-f-graminearum-sensu-stricto
#3
Tomasz Kulik, Kinga Stuper-Szablewska, Katarzyna Bilska, Maciej Buśko, Anna Ostrowska-Kołodziejczak, Dariusz Załuski, Juliusz Perkowski
Plant-derived compounds limiting mycotoxin contamination are currently of major interest in food and feed production. However, their potential application requires an evaluation of their effects on fungal secondary metabolism and membrane effects. In this study, different strains of Fusarium culmorum and F. graminearum sensu stricto were exposed to trans-cinnamic and chlorogenic acids on solid YES media. Fusaria produced phenolic acids, whose accumulation was lowered by exogenous phenolic compounds. In addition, fungi reduced exogenous phenolic acids, leading either to their conversion or degradation...
June 22, 2017: Toxins
https://www.readbyqxmd.com/read/28624282/effect-of-endoplasmic-reticulum-stress-on-metabolic-and-stress-signaling-and-kidney-specific-functions-in-madin-darby-bovine-kidney-cells
#4
E Chiappisi, R Ringseis, K Eder, D K Gessner
Recent studies demonstrated induction of endoplasmic reticulum (ER) stress in tissues of cows after parturition, but knowledge about the effect of ER stress on important cellular processes, such as critical signaling and metabolic pathways, in cattle is scarce. Thus, the present study aimed to investigate the effect of ER stress induction on nuclear factor-κB (NF-κB), nuclear factor E2-related factor 2 (Nrf2), and sterol regulatory element-binding protein (SREBF1) pathway in Madin-Darby bovine kidney (MDBK) cells, a widely used in vitro model in ruminant research...
June 14, 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/28611746/adaptations-to-high-salt-in-a-halophilic-protist-differential-expression-and-gene-acquisitions-through-duplications-and-gene-transfers
#5
Tommy Harding, Andrew J Roger, Alastair G B Simpson
The capacity of halophiles to thrive in extreme hypersaline habitats derives partly from the tight regulation of ion homeostasis, the salt-dependent adjustment of plasma membrane fluidity, and the increased capability to manage oxidative stress. Halophilic bacteria, and archaea have been intensively studied, and substantial research has been conducted on halophilic fungi, and the green alga Dunaliella. By contrast, there have been very few investigations of halophiles that are phagotrophic protists, i.e., protozoa...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28600071/synthetic-antimicrobial-peptides-of-the-halictines-family-disturb-the-membrane-integrity-of-candida-cells
#6
Marie Kodedová, Hana Sychrová
We compared the potency of four derivatives of the antimicrobial peptide halictine-2 against six Candida species. Observed activity was peptide and species specific. Halictines rapidly permeabilized cell membranes and caused the leakage of cytosolic components. Their killing potential was enhanced by the commercial antimicrobial agent octenidine dihydrochloride. The effect on C. glabrata cells did not depend on the activity of Cdr pumps, but was influenced by their lipid composition. The pre-treatment of cells with myriocin, an inhibitor of sphingolipid synthesis, enhanced the peptides' activity, whereas pre-treatment with terbinafine and fluconazole, inhibitors of sterol synthesis, significantly weakened their efficacy...
June 6, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28596107/a-novel-function-for-glucocerebrosidase-as-a-regulator-of-sterylglucoside-metabolism
#7
REVIEW
Hisako Akiyama, Yoshio Hirabayashi
BACKGROUND: Sterols are major cell membrane lipids, and in many organisms they are modified with glucose to generate sterylglucosides. Glucosylation dramatically changes the functional properties of sterols. The formation of sterylglucosides from sterols in plants, fungi, and bacteria uses UDP-glucose as a glucose donor. By contrast, sterylglucoside biosynthesis in mammals is catalyzed by the transglucosylation activity of glucocerebrosidases, with glucosylceramide acting as the glucose donor...
June 6, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28595398/simulations-of-simple-linoleic-acid-containing-lipid-membranes-and-models-for-the-soybean-plasma-membranes
#8
Xiaohong Zhuang, Anna Ou, Jeffery B Klauda
The all-atom CHARMM36 lipid force field (C36FF) has been tested with saturated, monounsaturated, and polyunsaturated lipids; however, it has not been validated against the 18:2 linoleoyl lipids with an unsaturated sn-1 chain. The linoleoyl lipids are common in plants and the main component of the soybean membrane. The lipid composition of soybean plasma membranes has been thoroughly characterized with experimental studies. However, there is comparatively less work done with computational modeling. Our molecular dynamics (MD) simulation results show that the pure linoleoyl lipids, 1-stearoyl-2-linoleoyl-sn-glycero-3-phosphocholine (18:0/18:2) and 1,2-dilinoleoyl-sn-glycero-3-phosphocholine (di-18:2), agree very well with the experiments, which demonstrates the accuracy of the C36FF for the computational study of soybean membranes...
June 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28591582/hepatocyte-abca1-deletion-impairs-liver-insulin-signaling-and-lipogenesis
#9
Chia-Chi C Key, Mingxia Liu, C Lisa Kurtz, Soonkyu Chung, Elena Boudyguina, Timothy A Dinh, Alexander Bashore, Peter E Phelan, Barry I Freedman, Timothy F Osborne, Xuewei Zhu, Lijun Ma, Praveen Sethupathy, Sudha B Biddinger, John S Parks
Plasma membrane (PM) free cholesterol (FC) is emerging as an important modulator of signal transduction. Here, we show that hepatocyte-specific knockout (HSKO) of the cellular FC exporter, ATP-binding cassette transporter A1 (ABCA1), leads to decreased PM FC content and defective trafficking of lysosomal FC to the PM. Compared with controls, chow-fed HSKO mice had reduced hepatic (1) insulin-stimulated Akt phosphorylation, (2) activation of the lipogenic transcription factor Sterol Regulatory Element Binding Protein (SREBP)-1c, and (3) lipogenic gene expression...
June 6, 2017: Cell Reports
https://www.readbyqxmd.com/read/28590904/niemann-pick-type-c-proteins-promote-microautophagy-by-expanding-raft-like-membrane-domains-in-the-yeast-vacuole
#10
Takuma Tsuji, Megumi Fujimoto, Tsuyako Tatematsu, Jinglei Cheng, Minami Orii, Sho Takatori, Toyoshi Fujimoto
Niemann-Pick type C is a storage disease caused by dysfunction of NPC proteins, which transport cholesterol from the lumen of lysosomes to the limiting membrane of that compartment. Using freeze fracture electron microscopy, we show here that the yeast NPC orthologs, Ncr1p and Npc2p, are essential for formation and expansion of raft-like domains in the vacuolar (lysosome) membrane, both in stationary phase and in acute nitrogen starvation. Moreover, the expanded raft-like domains engulf lipid droplets by a microautophagic mechanism...
June 7, 2017: ELife
https://www.readbyqxmd.com/read/28587792/breaking-fat-how-mycobacteria-and-other-intracellular-pathogens-manipulate-host-lipid-droplets
#11
REVIEW
Caroline Barisch, Thierry Soldati
Tuberculosis (Tb) is a lung infection caused by Mycobacterium tuberculosis (Mtb). With one third of the world population latently infected, it represents the most prevalent bacterial infectious diseases worldwide. Typically, persistence is linked to so-called "dormant" slow-growing bacteria, which have a low metabolic rate and a reduced response to antibiotic treatments. However, dormant bacteria regain growth and virulence when the immune system is weakened, leading again to the active form of the disease...
June 3, 2017: Biochimie
https://www.readbyqxmd.com/read/28582619/phytohormones-behavior-in-the-model-environment-of-plant-and-human-lipid-membranes
#12
Michał Flasiński, Paulina Swiechowicz
Interactions between three auxins (IAA, BNOA and 2,4-D) and model 2D lipid systems mimicking plant and human cell membranes were investigated in monolayers formed at the air/water solution interface. The analysis was based on the recorded π - A isotherm characteristics complemented with Brewster angle microscopy. The influence of auxins on model membranes was discussed on the basis of condensation changes, modification of mutual lipid - lipid interactions in the mixed films as well as morphological alteration of the surface domains on the microscopic scale...
June 5, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28564600/oxysterol-binding-protein-related-protein-1l-regulates-cholesterol-egress-from-the-endo-lysosomal-system
#13
Kexin Zhao, Neale D Ridgway
Lipoprotein cholesterol is delivered to the limiting membrane of late endosomes/lysosomes (LELs) by Niemann-Pick C1 (NPC1). However, the mechanism of cholesterol transport from LELs to the endoplasmic reticulum (ER) is poorly characterized. We report that oxysterol-binding protein-related protein 1L (ORP1L) is necessary for this stage of cholesterol export. CRISPR-mediated knockout of ORP1L in HeLa and HEK293 cells reduced esterification of cholesterol to the level in NPC1 knockout cells, and it increased the expression of sterol-regulated genes and de novo cholesterol synthesis, indicative of a block in cholesterol transport to the ER...
May 30, 2017: Cell Reports
https://www.readbyqxmd.com/read/28559213/phylogenomic-analysis-of-integral-diiron-membrane-histidine-motif-containing-enzymes-in-ciliates-provides-insights-into-their-function-and-evolutionary-relationships
#14
Nicolas G Cid, María L Sanchez Granel, María G Montes, María E Elguero, Clara B Nudel, Alejandro D Nusblat
The Integral Membrane Histidine Motif-containing Enzymes (IMHME) are a class of binuclear non-heme iron proteins widely distributed among prokaryotes and eukaryotes. They are characterized by a conserved tripartite motif consisting of eight to ten histidine residues. Their known function is the activation of the dioxygen moiety to serve as efficient catalysts for reactions of hydroxylation, desaturation or reduction. To date most studies on IMHME were carried out in metazoan, phototrophic or parasitic organisms, whereas genome-wide analysis in heterotrophic free living protozoa, such as the Ciliophora phylum, has not been undertaken...
May 27, 2017: Molecular Phylogenetics and Evolution
https://www.readbyqxmd.com/read/28553993/multi-phase-solvation-model-for-biological-membranes-molecular-action-mechanism-of-amphotericin-b
#15
J M Falcón-González, G Jiménez-Domínguez, I Ortega-Blake, M Carrillo-Tripp
Amphotericin B (AmB) is still the most effective drug for the treatment of systemic fungal infections in humans. Despite significant theoretical and experimental efforts trying to understand its molecular mechanism of action, the answer has remained elusive. In this work, we present a computational methodology to test the current membrane related hypotheses, namely, transmembrane ion channel, adsorption, and sterol sponge. We use a thermodynamic approach in which we represent the membrane by a multiphase solvation model with atomic detail (MMPSM) and calculate the free energy of transferring the drug between phases with different dielectric properties...
June 7, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/28549068/oligodendroglial-myelination-requires-astrocyte-derived-lipids
#16
Nutabi Camargo, Andrea Goudriaan, Anne-Lieke F van Deijk, Willem M Otte, Jos F Brouwers, Hans Lodder, David H Gutmann, Klaus-Armin Nave, Rick M Dijkhuizen, Huibert D Mansvelder, Roman Chrast, August B Smit, Mark H G Verheijen
In the vertebrate nervous system, myelination of axons for rapid impulse propagation requires the synthesis of large amounts of lipids and proteins by oligodendrocytes and Schwann cells. Myelin membranes are thought to be cell-autonomously assembled by these axon-associated glial cells. Here, we report the surprising finding that in normal brain development, a substantial fraction of the lipids incorporated into central nervous system (CNS) myelin are contributed by astrocytes. The oligodendrocyte-specific inactivation of sterol regulatory element-binding protein (SREBP) cleavage-activating protein (SCAP), an essential coactivator of the transcription factor SREBP and thus of lipid biosynthesis, resulted in significantly retarded CNS myelination; however, myelin appeared normal at 3 months of age...
May 2017: PLoS Biology
https://www.readbyqxmd.com/read/28545532/cytotoxicity-of-the-methanol-extracts-of-elephantopus-mollis-kalanchoe-crenata-and-4-other-cameroonian-medicinal-plants-towards-human-carcinoma-cells
#17
Victor Kuete, Fabrice W Fokou, Oğuzhan Karaosmanoğlu, Veronique P Beng, Hülya Sivas
BACKGROUND: Cancer still constitutes one of the major health concerns globally, causing serious threats on patients, their families, and the healthcare system. METHODS: In this study, the cytotoxicity of the methanol extract of Elephantopus mollis whole plant (EMW), Enantia chlorantha bark (ECB), Kalanchoe crenata leaves (KCL), Lophira alata bark (LAB), Millettia macrophylla leaves (MML) and Phragmanthera capitata leaves (PCL) towards five human solid cancer cell lines and normal CRL2120 fibroblasts, was evaluated...
May 25, 2017: BMC Complementary and Alternative Medicine
https://www.readbyqxmd.com/read/28544363/expression-patterns-of-sterol-transporters-npc1-and-npc2-in-the-cnidarian-dinoflagellate-symbiosis
#18
Vincent Dani, Fabrice Priouzeau, Marjolijn Mertz, Magali Mondin, Sophie Pagnotta, Sandra Lacas-Gervais, Simon K Davy, Cécile Sabourault
The symbiotic interaction between cnidarians (e.g. corals and sea anemones) and photosynthetic dinoflagellates of the genus Symbiodinium is triggered by both host-symbiont recognition processes and metabolic exchange between the two partners. The molecular communication is crucial for homeostatic regulation of the symbiosis, both under normal conditions and during stresses that further lead to symbiosis collapse. It is therefore important to identify and fully characterize the key players of this intimate interaction at the symbiotic interface...
May 22, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/28526017/the-effect-of-hypoxia-on-the-lipidome-of-recombinant-pichia-pastoris
#19
Núria Adelantado, Pablo Tarazona, Karlheinz Grillitsch, Xavier García-Ortega, Sergi Monforte, Francisco Valero, Ivo Feussner, Günther Daum, Pau Ferrer
BACKGROUND: Cultivation of recombinant Pichia pastoris (Komagataella sp.) under hypoxic conditions has a strong positive effect on specific productivity when the glycolytic GAP promoter is used for recombinant protein expression, mainly due to upregulation of glycolytic conditions. In addition, transcriptomic analyses of hypoxic P. pastoris pointed out important regulation of lipid metabolism and unfolded protein response (UPR). Notably, UPR that plays a role in the regulation of lipid metabolism, amino acid metabolism and protein secretion, was found to be upregulated under hypoxia...
May 19, 2017: Microbial Cell Factories
https://www.readbyqxmd.com/read/28524381/antifungal-activity-of-gallic-acid-in-vitro-and-in-vivo
#20
Zhi-Jian Li, Meng Liu, Gulina Dawuti, Qin Dou, Yu Ma, Heng-Ge Liu, Silafu Aibai
Gallic acid (GA) is a polyphenol natural compound found in many medicinal plant species, including pomegranate rind (Punica granatum L.), and has been shown to have antiinflammatory and antibacterial properties. Pomegranate rind is used to treat bacterial and fungal pathogens in Uyghur and other systems of traditional medicine, but, surprisingly, the effects of GA on antifungal activity have not yet been reported. In this study, we aimed to investigate the inhibitory effects of GA on fungal strains both in vitro and in vivo...
May 19, 2017: Phytotherapy Research: PTR
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