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https://www.readbyqxmd.com/read/28823016/de-novo-synthesis-of-linoleic-acid-in-multiple-collembola-species
#1
Miriama Malcicka, Joachim Ruther, Jacintha Ellers
Many ecological interactions in communities take place between consumers and the organisms they feed on. Continuous surplus of specific nutritional compounds in the diet may lead to evolutionary changes in the metabolic capacity of the consumer, leaving the biosynthesis of such compounds prone to genetic decay and render organisms auxotrophic. A nutrient that is essential to many organisms is the unsaturated fatty acid, linoleic acid (LA; 18:2n-6), which is important in the maintenance of cell membrane fluidity and as a precursor for signaling molecules...
August 19, 2017: Journal of Chemical Ecology
https://www.readbyqxmd.com/read/28819244/light-scattering-by-optically-trapped-vesicles-affords-unprecedented-temporal-resolution-of-lipid-raft-dynamics
#2
Liam Collard, David Perez-Guaita, Bayan H A Faraj, Bayden R Wood, Russell Wallis, Peter W Andrew, Andrew J Hudson
A spectroscopic technique is presented that is able to identify rapid changes in the bending modulus and fluidity of vesicle lipid bilayers on the micrometer scale, and distinguish between the presence and absence of heterogeneities in lipid-packing order. Individual unilamellar vesicles have been isolated using laser tweezers and, by measuring the intensity modulation of elastic back-scattered light, changes in the biophysical properties of lipid bilayers were revealed. Our approach offers unprecedented temporal resolution and, uniquely, physical transformations of lipid bilayers can be monitored on a length scale of micrometers...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28808346/evidence-that-listeria-innocua-modulates-its-membrane-s-stored-curvature-elastic-stress-but-not-fluidity-through-the-cell-cycle
#3
Samuel Furse, Martin Jakubec, Frode Rise, Huw E Williams, Catherine E D Rees, Øyvind Halskau
This paper reports that the abundances of endogenous cardiolipin and phosphatidylethanolamine halve during elongation of the Gram-positive bacterium Listeria innocua. The lyotropic phase behaviour of model lipid systems that describe these modulations in lipid composition indicate that the average stored curvature elastic stress of the membrane is reduced on elongation of the cell, while the fluidity appears to be maintained. These findings suggest that phospholipid metabolism is linked to the cell cycle and that changes in membrane composition can facilitate passage to the succeding stage of the cell cycle...
August 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28807609/cspb-of-an-arctic-bacterium-polaribacter-irgensii-kopri-22228-confers-extraordinary-freeze-tolerance
#4
Youn Hong Jung, Yoo Kyung Lee, Hong Kum Lee, Kyunghee Lee, Hana Im
Freezing temperatures are a major challenge for life at the poles. Decreased membrane fluidity, uninvited secondary structure formation in nucleic acids, and protein cold-denaturation all occur at cold temperatures. Organisms adapted to polar regions possess distinct mechanisms that enable them to survive in extremely cold environments. Among the cold-induced proteins, cold shock protein (Csp) family proteins are the most prominent. A gene coding for a Csp-family protein, cspB, was cloned from an arctic bacterium, Polaribacter irgensii KOPRI 22228, and overexpression of cspB greatly increased the freeze-survival rates of Escherichia coli hosts, to a greater level than any previously reported Csp...
July 31, 2017: Brazilian Journal of Microbiology: [publication of the Brazilian Society for Microbiology]
https://www.readbyqxmd.com/read/28780605/subcellular-membrane-fluidity-of-lactobacillus-delbrueckii-subsp-bulgaricus-under-cold-and-osmotic-stress
#5
Julie Meneghel, Stéphanie Passot, Stéphanie Cenard, Matthieu Réfrégiers, Frédéric Jamme, Fernanda Fonseca
Cryopreservation of lactic acid bacteria may lead to undesirable cell death and functionality losses. The membrane is the first target for cell injury and plays a key role in bacterial cryotolerance. This work aimed at investigating at a subcellular resolution the membrane fluidity of two populations of Lactobacillus delbrueckii subsp. bulgaricus when subjected to cold and osmotic stresses associated to freezing. Cells were cultivated at 42 °C in mild whey medium, and they were exposed to sucrose solutions of different osmolarities (300 and 1800 mOsm L(-1)) after harvest...
August 5, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28778116/caveolin-1-restricts-group-a-streptococcus-invasion-of-non-phagocytic-host-cells
#6
Jin Yan Lim, Timothy C Barnett, Michele Bastiani, Kerrie-Ann McMahon, Charles Ferguson, Richard I Webb, Robert G Parton, Mark J Walker
Caveolae are composed of two major proteins, caveolin-1 (CAV1) and cavin-1/polymerase transcript factor I (CAVIN1). Here we demonstrate that CAV1 levels modulate invasion of group A Streptococcus (GAS) into non-phagocytic mammalian cells. GAS showed enhanced internalization into CAV1 knockout mouse embryonic fibroblasts (MEFs), and CAV1 knockdown human epithelial HEp-2 cells, whereas over-expression of CAV1 in HEp-2 cells reduced GAS invasion. This effect was not dependent on the expression of the GAS fibronectin binding protein SfbI, which had previously been implicated in caveolae-mediated uptake...
August 4, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/28772148/a-type-ecg-and-egcg-dimers-inhibit-3t3-l1-differentiation-by-binding-to-cholesterol-in-lipid-rafts
#7
Wei Zhu, Xiangyi Deng, Jinming Peng, Bo Zou, Chunmei Li
The present study aimed to explore the underlying mechanisms of epicatechin-3-gallate-(4β→8, 2β→O→7)-epicatechin-3-gallate (A-type ECG dimer) and epigallocatechin-3-gallate-(4β→8, 2β→O→7)-epigallocatechin-3-gallate (A-type EGCG dimer) involved in their strong inhibitory effects on 3T3-L1 preadipocytes differentiation. In the synthetic "lipid raft-like" liposome, A-type ECG and EGCG dimers incorporated into the liposome with high affinity and decreased the fluidity of the liposome. In 3T3-L1 preadipocytes, A-type ECG and EGCG dimers possibly bonded to lipid rafts cholesterol and disrupted the integrity of lipid rafts, thus exerting their notable inhibitory effects on 3T3-L1 preadipocytes differentiation by suppressing mitotic clonal expansion process and mRNA levels of PPARγ, C/EBPα and SREBP1C...
June 24, 2017: Journal of Nutritional Biochemistry
https://www.readbyqxmd.com/read/28756672/unveiling-the-interaction-between-fatty-acid-modified-membrane-and-hydrophilic-imidazolium-based-ionic-liquid-understanding-the-mechanism-of-ionic-liquid-cytotoxicity
#8
Niloy Kundu, Shreya Roy, Devdeep Mukherjee, Tapas Kumar Maiti, Nilmoni Sarkar
Ionic liquids (ILs) are considered as "green solvents" for more than 2 decades. However, recent studies suggest that some ILs exhibit greater toxicity compared to common solvents. As a proactive effort to better understand the molecular origin of the cytotoxicity, the work herein presents the systemic characterization of the interaction between model membrane composed of fatty acids and popular imidazolium-based hydrophilic IL. The fusion kinetics between the vesicles demonstrates the swelling of the vesicle...
August 17, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28754610/secretory-phospholipase-a2-responsive-liposomes-exhibit-a-potent-anti-neoplastic-effect-in-vitro-but-induce-unforeseen-severe-toxicity-in-vivo
#9
Ragnhild Garborg Østrem, Ladan Parhamifar, Houman Pourhassan, Gael Clergeaud, Ole Lerberg Nielsen, Andreas Kjær, Anders Elias Hansen, Thomas Lars Andresen
The clinical use of liposomal drug delivery vehicles is often hindered by insufficient drug release. Here we present the rational design of liposomes optimized for secretory phospholipase A2 (sPLA2) triggered drug release, and test their utility in vitro and in vivo. We hypothesized that by adjusting the level of cholesterol in anionic, unsaturated liposomes we could tune the enzyme specificity based on membrane fluidity, thus obtaining liposomes with an improved therapeutic outcome and reduced side effects...
July 25, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/28752254/interaction-between-c18-fatty-acids-and-dope-peg2000-in-langmuir-monolayers-effect-of-degree-of-unsaturation
#10
Lai Ti Gew, Misni Misran
In this study, we address the effect of the cis-double bond in 1,2-dioleoyl-sn-glycero-3-phosphoethanolamide-N-[methoxy(polyethylene glycol)-2000, DOPE PEG2000 (DP), on the Langmuir monolayer of C18 fatty acids-namely, stearic acid (SA), oleic acid (L1), linoleic acid (L2), and linolenic acid (L3)-with the same head group but different degrees of saturation on their hydrocarbon chains. Negative values of Gibbs free energy of mixing (ΔG mix) were obtained throughout the investigated ranges of the unsaturated C18 fatty-acid (L1, L2 and L3) mixed systems, indicating that very strong attractions occurred between molecules in the monolayers...
July 27, 2017: Journal of Biological Physics
https://www.readbyqxmd.com/read/28741121/interaction-of-newly-platinum-ii-with-tris-2-carboxyethyl-phosphine-complex-with-dna-and-model-lipid-membrane
#11
Hanna Pruchnik, Teresa Kral, Martin Hof
Structural properties of plasmid DNA and model lipid membrane treated with newly synthesized platinum(II) complex cis-[PtCl2{P(CH2CH2COOH)3}2] (cis-DTCEP for short) were studied and compared with effects of anticancer drug cisplatin, cis-[Pt(NH3)2Cl2] (cis-DDP for short). Time Correlated Single Photon Counting Fluorescence Correlation Spectroscopy (TCSPC-FCS) was employed to study interactions between those platinum complexes and DNA. The TCSPC-FCS results suggest that bonding of cis-DTCEP derivative to DNA leads to plasmid strain realignment towards much more compact structure than in the case of cis-DDP...
July 25, 2017: Journal of Membrane Biology
https://www.readbyqxmd.com/read/28740349/functional-lipidomics-in-patients-on-home-parenteral-nutrition-effect-of-lipid-emulsions
#12
Loris Pironi, Mariacristina Guidetti, Ornella Verrastro, Claudia Iacona, Federica Agostini, Caterina Pazzeschi, Anna Simona Sasdelli, Michele Melchiorre, Carla Ferreri
AIM: To investigate the fatty acid-based functional lipidomics of patients on long-term home parenteral nutrition receiving different intravenous lipid emulsions. METHODS: A cross-sectional comparative study was carried out on 3 groups of adults on home parenteral nutrition (HPN), receiving an HPN admixture containing an olive-soybean oil-based intravenous lipid emulsion (IVLE) (OO-IVLE; n = 15), a soybean- medium-chain triacylglycerol-olive-fish oil-based IVLE (SMOF-IVLE; n = 8) or HPN without IVLE (No-IVLE; n = 8) and 42 healthy controls (HCs)...
July 7, 2017: World Journal of Gastroenterology: WJG
https://www.readbyqxmd.com/read/28740256/influence-of-doxorubicin-on-model-cell-membrane-properties-insights-from-in-vitro-and-in-silico-studies
#13
Ana Catarina Alves, Aniket Magarkar, Miguel Horta, Jose L F C Lima, Alex Bunker, Cláudia Nunes, Salette Reis
Despite doxorubicin being commonly used in chemotherapy there still remain significant holes in our knowledge regarding its delivery efficacy and an observed resistance mechanism that is postulated to involve the cell membrane. One possible mechanism is the efflux by protein P-gp, which is found predominantly in cholesterol enriched domains. Thereby, a hypothesis for the vulnerability of doxorubicin to efflux through P-gp is its enhanced affinity for the ordered cholesterol rich regions of the plasma membrane...
July 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28738302/abnormal-pinocytosis-and-valence-variable-behaviors-of-cerium-suggested-a-cellular-mechanism-for-plant-yield-reduction-induced-by-environmental-cerium
#14
Lihong Wang, Jingfang He, Qing Yang, Xiaofen Lv, Jigang Li, David D Y Chen, Xiaolan Ding, Xiaohua Huang, Qing Zhou
The environmental safety of cerium (Ce) applications in many fields has been debated for almost a century because the cellular effects of environmental Ce on living organisms remain largely unclear. Here, using new, interdisciplinary methods, we surprisingly found that after Ce(III) treatment, Ce(III) was first recognized and anchored on the plasma membrane in leaf cells. Moreover, some trivalent Ce(III) was oxidized to tetravalent Ce(IV) in this organelle, which activated pinocytosis. Subsequently, more anchoring sites and stronger valence-variable behavior on the plasma membrane caused stronger pinocytosis to transport Ce(III and IV) into the leaf cells...
July 21, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28730698/boar-sperm-quality-after-supplementation-of-diets-with-omega-3-polyunsaturated-fatty-acids-extracted-from-microalgae
#15
Y T Andriola, F Moreira, E Anastácio, F A Camelo, A C Silva, A S Varela, S M M Gheller, K L Goularte, C D Corcini, T Lucia
This study evaluated effects of diet supplementation with omega-3 polyunsaturated fatty acids (PUFA) from microalgae on boar sperm quality. Two groups of boars (n = 3 each) were fed during 75 days either a commercial diet (control), or the same diet supplemented with omega-3 PUFA from the heterotrophic microalgae Schizochytrium sp. (120 g/kg). Sixteen ejaculates were collected per boar. Some sperm kinetics parameters were inferior for supplemented than for control boars (p < .05): distance average path; distance in both curved and straight line; velocity average path, velocity in both curved and straight line; and amplitude of lateral head displacement...
July 21, 2017: Andrologia
https://www.readbyqxmd.com/read/28728969/a-nanoporous-titanium-surface-promotes-the-maturation-of-focal-adhesions-and-the-formation-of-filopodia-with-distinctive-nanoscale-protrusions-by-osteogenic-cells
#16
Dainelys Guadarrama Bello, Aurélien Fouillen, Antonella Badia, Antonio Nanci
While topography is a key determinant of the cellular response to biomaterials the mechanisms implicated in the cell-surface interactions are complex and still not fully elucidated. In this context, we have examined the effect of nanoscale topography on the formation of filopodia, focal adhesions, and on gene expression of proteins associated with cell adhesion and sensing. Commercially pure titanium discs were treated for oxidative nanopatterning with a solution of H2SO4/H2O2 50:50 (v/v). Scanning electron microscopy and atomic force microscopy characterizations showed that this facile chemical treatment efficiently creates a unique nanoporous surface with a root-mean-square roughness of 11...
July 17, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28720839/effect-of-head-group-and-lipid-tail-oxidation-in-the-cell-membrane-revealed-through-integrated-simulations-and-experiments
#17
M Yusupov, K Wende, S Kupsch, E C Neyts, S Reuter, A Bogaerts
We report on multi-level atomistic simulations for the interaction of reactive oxygen species (ROS) with the head groups of the phospholipid bilayer, and the subsequent effect of head group and lipid tail oxidation on the structural and dynamic properties of the cell membrane. Our simulations are validated by experiments using a cold atmospheric plasma as external ROS source. We found that plasma treatment leads to a slight initial rise in membrane rigidity, followed by a strong and persistent increase in fluidity, indicating a drop in lipid order...
July 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28720385/differences-of-lipid-membrane-modulation-and-oxidative-stress-by-digoxin-and-21-benzylidene-digoxin
#18
Lilian Nd Silva, Silmara Lg Alves, Jessica Venugopal, Vanessa F Cortes, Herica L Santos, José Afp Villar, Leandro A Barbosa
Cardiotonic steroids (CTS) are compounds which bind to the Na,K-ATPase, leading to its inhibition and in some cases initiating signaling cascades. Long utilized as a treatment for congestive heart disease, CTS have more recently been observed to inhibit proliferation and cause apoptosis in several cancer cell lines. A synthetic derivative of the CTS digoxin, called 21-benzylidene digoxin (21-BD), activates the Na,K-ATPase rather than cause its inhibition, as its parent compound does. Here, the mechanism behind the unique effects of 21-BD are further explored...
July 15, 2017: Experimental Cell Research
https://www.readbyqxmd.com/read/28711161/role-of-fatty-acids-in-cold-adaptation-of-antarctic-psychrophilic-flavobacterium-spp
#19
Stanislava Králová
Cold-loving microorganisms developed numerous adaptation mechanisms allowing them to survive in extremely cold habitats, such as adaptation of the cell membrane. The focus of this study was on the membrane fatty acids of Antarctic Flavobacterium spp., and their adaptation response to cold-stress. Fatty acids and cold-response of Antarctic flavobacteria was also compared to mesophilic and thermophilic members of the genus Flavobacterium. The results showed that the psychrophiles produced more types of major fatty acids than meso- and thermophilic members of this genus, namely C15:1 iso G, C15:0 iso, C15:0 anteiso, C15:1ω6c, C15:0 iso 3OH, C17:1ω6c, C16:0 iso 3OH and C17:0 iso 3OH, summed features 3 (C16:1ω7cand/or C16:1ω6c) and 9 (C16:0 10-methyl and/or C17:1 iso ω9c)...
July 3, 2017: Systematic and Applied Microbiology
https://www.readbyqxmd.com/read/28710349/lipid-driven-nanodomains-in-giant-lipid-vesicles-are-fluid-and-disordered
#20
Alena Koukalová, Mariana Amaro, Gokcan Aydogan, Gerhard Gröbner, Philip T F Williamson, Ilya Mikhalyov, Martin Hof, Radek Šachl
It is a fundamental question in cell biology and biophysics whether sphingomyelin (SM)- and cholesterol (Chol)- driven nanodomains exist in living cells and in model membranes. Biophysical studies on model membranes revealed SM and Chol driven micrometer-sized liquid-ordered domains. Although the existence of such microdomains has not been proven for the plasma membrane, such lipid mixtures have been often used as a model system for 'rafts'. On the other hand, recent super resolution and single molecule results indicate that the plasma membrane might organize into nanocompartments...
July 14, 2017: Scientific Reports
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