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Skorup I, Valentino G, Aleandri S, Gelli R, Ganguin AA, Felli E, Selicean SE, Marxer RA, Teworte S, Lucić A, Gracia-Sancho J, Berzigotti A, Ridi F, Luciani P. Polyenylphosphatidylcholine as bioactive excipient in tablets for the treatment of liver fibrosis. Int J Pharm 2023; 646:123473. [PMID: 37788730 DOI: 10.1016/j.ijpharm.2023.123473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 08/24/2023] [Accepted: 09/30/2023] [Indexed: 10/05/2023]
Abstract
Liver fibrosis is a condition characterized by the accumulation of extracellular matrix (ECM) arising from the myofibroblastic transdifferentiation of hepatic stellate cells (HSCs) occurring as the natural response to liver damage. To date, no pharmacological treatments have been specifically approved for liver fibrosis. We recently reported a beneficial effect of polyenylphosphatidylcholines (PPCs)-rich formulations in reverting fibrogenic features of HSCs. However, unsaturated phospholipids' properties pose a constant challenge to the development of tablets as preferred patient-centric dosage form. Profiting from the advantageous physical properties of the PPCs-rich Soluthin® S 80 M, we developed a tablet formulation incorporating 70% w/w of this bioactive lipid. Tablets were characterized via X-ray powder diffraction, thermogravimetry, and Raman confocal imaging, and passed the major compendial requirements. To mimic physiological absorption after oral intake, phospholipids extracted from tablets were reconstituted as protein-free chylomicron (PFC)-like emulsions and tested on the fibrogenic human HSC line LX-2 and on primary cirrhotic rat hepatic stellate cells (PRHSC). Lipids extracted from tablets and reconstituted in buffer or as PFC-like emulsions exerted the same antifibrotic effect on both activated LX-2 and PRHSCs as observed with plain S 80 M liposomes, showing that the manufacturing process did not interfere with the bioactivity of PPCs.
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Affiliation(s)
- Ivo Skorup
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Gina Valentino
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Simone Aleandri
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Rita Gelli
- Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, Sesto Fiorentino, Florence, Italy
| | - Aymar Abel Ganguin
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Eric Felli
- Department of Visceral Surgery and Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland; Department for BioMedical Research, Hepatology, University of Bern, Bern, Switzerland
| | - Sonia Emilia Selicean
- Department of Visceral Surgery and Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland; Department for BioMedical Research, Hepatology, University of Bern, Bern, Switzerland
| | - Rosanne Angela Marxer
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Sarah Teworte
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Ana Lucić
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Jordi Gracia-Sancho
- Department of Visceral Surgery and Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland; Department for BioMedical Research, Hepatology, University of Bern, Bern, Switzerland; Liver Vascular Biology Research Group, CIBEREHD, IDIBAPS Research Institute, Barcelona, Spain
| | - Annalisa Berzigotti
- Department of Visceral Surgery and Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland; Department for BioMedical Research, Hepatology, University of Bern, Bern, Switzerland
| | - Francesca Ridi
- Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, Sesto Fiorentino, Florence, Italy
| | - Paola Luciani
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland.
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Abdel Azim EA, Elkheshen SA, Hathout RM, Fouly MA, El Hoffy NM. Augmented in vitro and in vivo Profiles of Brimonidine Tartrate Using Gelatinized-Core Liposomes. Int J Nanomedicine 2022; 17:2753-2776. [PMID: 35782018 PMCID: PMC9243147 DOI: 10.2147/ijn.s370192] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 06/07/2022] [Indexed: 11/23/2022] Open
Abstract
Background The low entrapment efficiency of the hydrophilic drugs such as brimonidine tartrate (BRT) in liposomes represents a challenge that requires interventions. Gelatinized core liposomes (GCLs) were fabricated to increase the drug entrapment, corneal penetration, and physical stability of the investigated molecule. Research Design and Methods GCLs encapsulating BRT were prepared and optimized utilizing D-optimal design (DOD). The effect of plasticizer incorporation on the physicochemical characteristics and on the in vivo performance was studied. The optimized formulations were investigated for pH, rheological properties, morphological characteristics, in vitro release profiles, biological performance, safety profile. The effects of storage and gamma sterilization were also investigated. Results The results revealed the great success of the prepared formulations to achieve high entrapment efficiency reaching 98% after a maturation period of 10 days. The addition of glycerol as plasticizer significantly minimized the particle size and shortened the maturation period to 7 days. The selected formulations were stable for 3 months after gamma sterilization. The formulations showed significant lowering of intra-ocular pressure (IOP) in glaucomatous rabbits with sustainment of the pharmacological effect for 24 hours compared to drug solution. Conclusions Enhanced in vitro and in vivo profiles of brimonidine tartrate loaded gelatinized-core-liposomes were obtained.
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Affiliation(s)
- Engy A Abdel Azim
- Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, Future University in Egypt, New Cairo, Cairo, 11835, Egypt
| | - Seham A Elkheshen
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt
| | - Rania M Hathout
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
- Correspondence: Rania M Hathout, Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Ain Shams University, African Union Organization Street, P.O. Box: 11566, Abbassia, Cairo, Egypt, Email ;
| | - Marwa A Fouly
- Research Institute of Ophthalmology, Giza, Cairo, 12557, Egypt
| | - Nada M El Hoffy
- Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, Future University in Egypt, New Cairo, Cairo, 11835, Egypt
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Lipid Self-Assemblies under the Atomic Force Microscope. Int J Mol Sci 2021; 22:ijms221810085. [PMID: 34576248 PMCID: PMC8467407 DOI: 10.3390/ijms221810085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 08/26/2021] [Accepted: 08/27/2021] [Indexed: 12/13/2022] Open
Abstract
Lipid model membranes are important tools in the study of biophysical processes such as lipid self-assembly and lipid–lipid interactions in cell membranes. The use of model systems to adequate and modulate complexity helps in the understanding of many events that occur in cellular membranes, that exhibit a wide variety of components, including lipids of different subfamilies (e.g., phospholipids, sphingolipids, sterols…), in addition to proteins and sugars. The capacity of lipids to segregate by themselves into different phases at the nanoscale (nanodomains) is an intriguing feature that is yet to be fully characterized in vivo due to the proposed transient nature of these domains in living systems. Model lipid membranes, instead, have the advantage of (usually) greater phase stability, together with the possibility of fully controlling the system lipid composition. Atomic force microscopy (AFM) is a powerful tool to detect the presence of meso- and nanodomains in a lipid membrane. It also allows the direct quantification of nanomechanical resistance in each phase present. In this review, we explore the main kinds of lipid assemblies used as model membranes and describe AFM experiments on model membranes. In addition, we discuss how these assemblies have extended our knowledge of membrane biophysics over the last two decades, particularly in issues related to the variability of different model membranes and the impact of supports/cytoskeleton on lipid behavior, such as segregated domain size or bilayer leaflet uncoupling.
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Jin J, Xie D, Chen H, Wang X, Jin Q, Wang X. Production of Rice Bran Oil with Light Color and High Oryzanol Content by Multi-stage Molecular Distillation. J AM OIL CHEM SOC 2015. [DOI: 10.1007/s11746-015-2747-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Axpe E, García-Arribas AB, Mujika JI, Mérida D, Alonso A, Lopez X, García JA, Ugalde JM, Goñi FM, Plazaola F. Ceramide increases free volume voids in DPPC membranes. RSC Adv 2015. [DOI: 10.1039/c5ra05142h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We have measured by positron annihilation lifetime spectroscopy (PALS) that ceramide increases the size of the free volume holes in DPPC lipid membranes.
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Affiliation(s)
- E. Axpe
- Department of Electricity and Electronics
- University of the Basque Country (UPV/EHU)
- Leioa
- Spain
| | | | - J. I. Mujika
- Kimika Fakultatea
- Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC)
- Donostia
- Spain
| | - D. Mérida
- Department of Electricity and Electronics
- University of the Basque Country (UPV/EHU)
- Leioa
- Spain
| | - A. Alonso
- Unidad de Biofísica (CSIC
- UPV/EHU)
- 48940 Leioa
- Spain
- Departamento de Bioquímica
| | - X. Lopez
- Kimika Fakultatea
- Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC)
- Donostia
- Spain
| | - J. A. García
- Department of Applied Physics II
- University of the Basque Country (UPV/EHU)
- Leioa
- Spain
| | - J. M. Ugalde
- Kimika Fakultatea
- Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC)
- Donostia
- Spain
| | - F. M. Goñi
- Unidad de Biofísica (CSIC
- UPV/EHU)
- 48940 Leioa
- Spain
- Departamento de Bioquímica
| | - F. Plazaola
- Department of Electricity and Electronics
- University of the Basque Country (UPV/EHU)
- Leioa
- Spain
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Ahyayauch H, Collado MI, Alonso A, Goñi FM. Lipid bilayers in the gel phase become saturated by triton X-100 at lower surfactant concentrations than those in the fluid phase. Biophys J 2012; 102:2510-6. [PMID: 22713566 DOI: 10.1016/j.bpj.2012.04.041] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 04/18/2012] [Accepted: 04/24/2012] [Indexed: 11/30/2022] Open
Abstract
It has been repeatedly observed that lipid bilayers in the gel phase are solubilized by lower concentrations of Triton X-100, at least within certain temperature ranges, or other nonionic detergents than bilayers in the fluid phase. In a previous study, we showed that detergent partition coefficients into the lipid bilayer were the same for the gel and the fluid phases. In this contribution, turbidity, calorimetry, and 31P-NMR concur in showing that bilayers in the gel state (at least down to 13-20°C below the gel-fluid transition temperature) become saturated with detergent at lower detergent concentrations than those in the fluid state, irrespective of temperature. The different saturation may explain the observed differences in solubilization.
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Affiliation(s)
- Hasna Ahyayauch
- Unidad de Biofísica (Centro Mixto CSIC-UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
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Demana PH, Davies NM, Hook S, Rades T. Quil A–lipid powder formulations releasing ISCOMs and related colloidal stuctures upon hydration. J Control Release 2005; 103:45-59. [PMID: 15710499 DOI: 10.1016/j.jconrel.2004.11.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2004] [Revised: 10/29/2004] [Accepted: 11/01/2004] [Indexed: 10/25/2022]
Abstract
The aim of the present study was to prepare solid Quil A-cholesterol-phospholipid formulations (as powder mixtures or compressed to pellets) by physical mixing or by freeze-drying of aqueous dispersions of these components in ratios that allow spontaneous formation of ISCOMs and other colloidal structures upon hydration. The effect of addition of excess cholesterol to the lipid mixtures on the release of a model antigen (PE-FITC-OVA) from the pellets was also investigated. Physical properties were evaluated by X-ray powder diffractometry (XPRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and polarized light microscopy (PLM). Characterization of aqueous colloidal dispersions was performed by negative staining transmission electron microscopy (TEM). Physically mixed powders (with or without PE-FITC-OVA) and pellets prepared from the same powders did not spontaneously form ISCOM matrices and related colloidal structures such as worm-like micelles, ring-like micelles, lipidic/layered structures and lamellae (hexagonal array of ring-like micelles) upon hydration as expected from the pseudo-ternary diagram for aqueous mixtures of Quil A, cholesterol and phospholipid. In contrast, spontaneous formation of the expected colloids was demonstrated for the freeze-dried lipid mixtures. Pellets prepared by compression of freeze-dried powders released PE-FITC-OVA slower than those prepared from physically mixed powders. TEM investigations revealed that the antigen was released in the form of colloidal particles (ISCOMs) from pellets prepared by compression of freeze-dried powders. The addition of excess cholesterol slowed down the release of antigen. The findings obtained in this study are important for the formulation of solid Quil A-containing lipid articles as controlled particulate adjuvant containing antigen delivery systems.
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Affiliation(s)
- Patrick H Demana
- New Zealand National School of Pharmacy, University of Otago, Dunedin, New Zealand
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Holthuis JC, Pomorski T, Raggers RJ, Sprong H, Van Meer G. The organizing potential of sphingolipids in intracellular membrane transport. Physiol Rev 2001; 81:1689-723. [PMID: 11581500 DOI: 10.1152/physrev.2001.81.4.1689] [Citation(s) in RCA: 240] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Eukaryotes are characterized by endomembranes that are connected by vesicular transport along secretory and endocytic pathways. The compositional differences between the various cellular membranes are maintained by sorting events, and it has long been believed that sorting is based solely on protein-protein interactions. However, the central sorting station along the secretory pathway is the Golgi apparatus, and this is the site of synthesis of the sphingolipids. Sphingolipids are essential for eukaryotic life, and this review ascribes the sorting power of the Golgi to its capability to act as a distillation apparatus for sphingolipids and cholesterol. As Golgi cisternae mature, ongoing sphingolipid synthesis attracts endoplasmic reticulum-derived cholesterol and drives a fluid-fluid lipid phase separation that segregates sphingolipids and sterols from unsaturated glycerolipids into lateral domains. While sphingolipid domains move forward, unsaturated glycerolipids are retrieved by recycling vesicles budding from the sphingolipid-poor environment. We hypothesize that by this mechanism, the composition of the sphingolipid domains, and the surrounding membrane changes along the cis-trans axis. At the same time the membrane thickens. These features are recognized by a number of membrane proteins that as a consequence of partitioning between domain and environment follow the domains but can enter recycling vesicles at any stage of the pathway. The interplay between protein- and lipid-mediated sorting is discussed.
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Affiliation(s)
- J C Holthuis
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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9
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Kaneko T, Sagitani H. Formation of homogeneous liposomes with high trapping efficiency by the surface chemical method. ACTA ACUST UNITED AC 1992. [DOI: 10.1016/0166-6622(92)80223-o] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Paleos CM, Margomenou-leonidopoulou G, Malliaris A. Organizational and Aggregational Characteristics of Some Monomeric and Polymerized Quaternary Ammonium Salts. ACTA ACUST UNITED AC 1988. [DOI: 10.1080/00268948808070263] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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11
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Robson RJ, Dennis EA. Mixed micelles of sphingomyelin and phosphatidylcholine with nonionic surfactants. Effect of temperature and surfactant polydispersity. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 573:489-500. [PMID: 465516 DOI: 10.1016/0005-2760(79)90223-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mixed micelle formation of the polydisperse nonionic surfactant Triton X-100 as well as its homogeneous analogue, p-(1,1,3,3-tetramethylbutyl)-phenoxynonaoxyethylene glycol (OPE-9), with bovine brain sphingomyelin or dipalmitoyl phosphatidylcholine has been characterized by column chromatography on 6% agarose. At 40 degrees C, mixtures of OPE-9 and either sphingomyelin or dipalmitoyl phosphatidylcholine give a narrow size distribution for mixed micelles. A this temperature the size distribution of Triton X-100-containing mixed micelles is complicated because of the polydispersity of the oxyethylene chains. At 20 degrees C narrow size distributions are observed for mixed micelles of sphingomyelin/Triton X-100 and sphingomyelin/OPE-9 up to at least 0.06 mol fraction of lipid. For dipalmitoyl phosphatidylcholine this is observed only with OPE-9. At intermediate mol fractions of lipid (around 0.25), two populations of mixed micelles exist for sphingomyelin/Trition X-100, sphingomyelin/OPE-9, and dipalmitoyl phosphatidylcholine/OPE-9. At high mol fractions of lipid only one population of mixed micelles again exists. At 20 degrees C, sphingoymelin forms a clear solution with Triton X-100 and OPE-9 to a lipid mol fraction of at least 0.46 and 0.67, respectively. Dipalmitoyl phosphatidylcholine forms a clear solution with OPE-9 to a lipid mol fraction of at least 0.57 at the same temperature. Triton X-100 and dipalmitoyl phosphatidylcholine do not form stable, clear solutions at 20 degrees C unless the lipid mol fraction is extremely low. These results show that surfactant polydispersity and temperature are important determinants in the solubilization of lipids by nonionic surfactants. It is also shown that pure surfactant micelles and lipid/surfactant mixed micelles do not co-exist in the same solution.
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12
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Quinn PJ, Williams WP. Plant lipids and their role in membrane function. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1979; 34:109-73. [PMID: 375299 DOI: 10.1016/0079-6107(79)90016-6] [Citation(s) in RCA: 133] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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13
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Gershfeld NL. Equilibrium studies of lecithin-cholesterol interactions I. Stoichiometry of lecithin-cholesterol complexes in bulk systems. Biophys J 1978; 22:469-88. [PMID: 667296 PMCID: PMC1473484 DOI: 10.1016/s0006-3495(78)85500-3] [Citation(s) in RCA: 103] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The maximum molar ratio of lecithin:cholesterol in aqueous dispersions has been reported to be 2:1, 1:1, or 1:2. The source of the desparate results has been examined in this study by analyzing (a) the phase relations in anhydrous mixtures (from which most dispersions are prepared) and (b) various methods of preparing aqueous dispersions, with the purpose of avoiding the formation of metastable states that may be responsible for the variability of the lecithin-cholesterol stoichiometry. Temperature-composition phase diagrams for anhydrous mixtures of cholesterol (CHOL) with dimyristoyl (DML) and with dipalmitoyl (DPL) lecithin were obtained by differential scanning calorimetry (DSC). Complexes form with molar ratios for lecithin:CHOL of 2:1 and 1:2; they are stable up to 70 degrees C. When x(CHOL) < 0.33, two phases coexist: complex (2:1) plus pure lecithin; when 0.33 < x(CHOL) < 0.67 complexes (2:1) and (1:2) coexist as separate phases. The corresponding phase diagram in water for these mixtures was determined by DSC and isopycnic centrifugation in D(2)O-H(2)O gradients. Aqueous dispersions were prepared by various methods (vortexing, dialysis, sonication) yielding identical results except as noted below. The data presented supports the following phase relations. When x(CHOL) < 0.33, two lipid phases coexist: pure lecithin plus complex (2:1) where the properties of the lecithin phase are determined by whether the temperature is below or above T(c), the gel-liquid crystal transition temperature. Therefore, complex (2:1) will coexist with gel state below T(c) and with liquid crystal above T(c). The densities follow in the order gel > complex (2:1) > liquid crystal. The density of complex (2:1) is less sensitive to temperature in the range 5 degrees -45 degrees C compared to the temperature dependence for DML and DPL where large changes in density occur at T(c). When x(CHOL) > 0.33, CHOL phase coexists with complex (2:1); anhydrous complex (1:2) is apparently not stable in H(2)O. The results are independent of the method and temperature used for preparing the lipid dispersions. However, when dispersions are prepared by sonication or with solvents at T > T(c), an apparent 1:1 complex is formed. Evidence suggests the 1:1 complex is metastable.
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14
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Behof AF, Koza RA, Lach LE, Yi PN. Phase transitions in phosphatidylcholine dispersion observed with an interference refractometer. Biophys J 1978; 22:37-48. [PMID: 638225 PMCID: PMC1473404 DOI: 10.1016/s0006-3495(78)85469-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
An interferometer is used to measure the refractive index change accompanying the crystal-to-liquid-crystal phase transition in the dispersion of phosphatidylcholines. Two separate methods of obtaining the refractive index change are employed: the first method analyzes the intensity transmitted through a spatial filter and the second method utilizes a piezoeletric crystal-based electronic compensator. The results of the two methods agree well. The accuracy of the apparatus (6 X 10(-6)) permitted us to use a very dilute sample to detect the phase change. Only a fraction of a milligram of dry lecithin is needed to observe the change. The result confirms conclusively that the major reason for the turbidity change at the transition temperature is the alteration in the refractive index of the lipid membranes. The fractional change in the refractive index does not agree well with the fractional change in the density of lipid molecules in vesicles.
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15
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Tsong TY, Kanehisa MI. Relaxation phenomena in aqueous dispersions of synthetic lecithins. Biochemistry 1977; 16:2674-80. [PMID: 889783 DOI: 10.1021/bi00631a014] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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16
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Greenwald SM, Hancock AJ, Sable HZ, D'Esposito L, Koenig JL. Analogs of natural lipids. II. Polymorphic behavior of the tris-homoacyl derivatives of cyclopentane-1,2,3-triols. Chem Phys Lipids 1977; 18:154-69. [PMID: 856480 DOI: 10.1016/0009-3084(77)90003-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The polymorphic behavior of three series of tris-homoacyl (C14:0, C16:0 and C18:0) cyclopentane-1,2,3-triol analogs of the natural saturated triglycerides has been studied using differential thermal analysis, Fourier transform infrared spectroscopy, and X-ray diffraction. It was found that the triglyceride analogs derived from the 1,2,3/0 and 1,2/3 cyclopentanetriols exhibit different polymorphic behavior than that of the natural triglycerides. The analogs derived from 1,3/2 cyclopentanetriol, however, were found to parallel the polymorphic behavior of the natural triglycerides quite closely. This polymorphic behavior is discussed in terms of the different configurations which the chains assume in each of the triglyceride analogs.
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17
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Chapman D, Peel WE, Kingston B, Lilley TH. Lipid phase transitions in model biomembranes. The effect of ions on phosphatidylcholine bilayers. BIOCHIMICA ET BIOPHYSICA ACTA 1977; 464:260-75. [PMID: 831797 DOI: 10.1016/0005-2736(77)90002-5] [Citation(s) in RCA: 125] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Differential scanning calorimetry has been used to study the endothermic phase behaviour of some model biomembranes (i.e. phosphatidylcholine-water systes) in the presence of a wide range of alkaline, alkaline earth and heavy metal salts. Studies and comparisons were made of both cation and anion effects. Shifts occur in the temperatures of both the pre-transition and main transition endotherms. The observed shifts are smaller than those which have been reported for charged lipids, and no evidence has been found for the formation of specific complexes. Electron microscopic studies on freez-fractured dispersions of phosphatidylcholine-water-salt systems show that with some salts the typical rippled surface observed with L-alpha-dimyristoyl phosphatidylcholine, when in the gel state, is replaced by a smooth surface.
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18
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Duppel W, Ullrich V. Membrane effects on drug monooxygenation activity in hepatic microsomes. BIOCHIMICA ET BIOPHYSICA ACTA 1976; 426:399-407. [PMID: 817739 DOI: 10.1016/0005-2736(76)90385-0] [Citation(s) in RCA: 81] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The temperature dependence of drug monooxygenation in phenobarbital-induced rat liver microsomes has been investigated. With 7-ethoxycoumarin as a substrate the activity of the microsomes could be measured down to 0 degrees C by the increase in fluorescence of the dealkylated reaction product 7-hydroxycoumarin (umbelliferone). Arrhenius plots of the activities at various temperatures between 0 degrees C and 45 degrees C showed a break in the activation energy around 20 degrees C. Addition of deoxycholate or high concentrations of glycerol, known to solubilize membrane-bound enzymes, abolished the break of the activation energy. Cholesterol, incorporated into the microsomal membrane in amounts equimolar to the microsomal phospholipid content led to a decrease of the activation energy at low temperatures and to an increase at higher temperatures, resulting in a loss of the break. The activity of microsomal NADPH-cytochrome c reductase with the water -soluble electron acceptor dichlorophenolindophenol showed no discontinuity in the Arrhenius plot. In addition the cumene hydroperoxide-mediated and cytochrome P-450-dependent O-dealkylation of 7-ethoxycoumarin proceeded without a break in the activation energy. It is concluded that phospholipid phase transitions affect the electron transfer from the reductase to cytochrome P-450.
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Abstract
The concept that the liquid crystalline or mesomorphic condition was of importance to biological systems is a relatively old idea. Thus Bernal (1933) when discussing the different types of arrangements of molecules in liquid crystals commented ‘Such structures belong to the liquid crystal as a unit and not to its molecules which may be replaced by others without destroying them and they persist in spite of the complete fluidity of the substance. These are just the properties to be required for a degree of organization between that of the continuous substance, liquid or crystalline solid and even the simplest living cell.’ Stewart (1961) some thirty years later also stated that ‘It is this property – the combination of flow and lability with a preferred and relatively stable molecular orientation – that makes the mesomorphic (i.e. liquid crystal) phase uniquely appropriate to the structure of protoplasm and living tissue.’
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Horwitz C, Krut L, Kaminsky L. Cholesterol uptake by egg-yolk phosphatidylcholine. BIOCHIMICA ET BIOPHYSICA ACTA 1971; 239:329-36. [PMID: 5165846 DOI: 10.1016/0005-2760(71)90178-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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22
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23
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Diamond RJ, Rose AH. Osmotic properties of spheroplasts from Saccharomyces cerevisiae grown at different temperatures. J Bacteriol 1970; 102:311-9. [PMID: 4986757 PMCID: PMC247553 DOI: 10.1128/jb.102.2.311-319.1970] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Spheroplasts were prepared from cells of Saccharomyces cerevisiae NCYC 366, grown at 30 or 15 C, by incubating cells with snail-gut juice after pretreatment with 2-mercaptoethanol. Walls of cells grown batchwise or in continuous culture at 15 C were more resistant to digestion with snail juice than walls on cells grown under the same conditions as 30 C. Spheroplasts lysed when suspended in hypotonic solutions of mannitol. The resistance of spheroplasts to osmotic lysis tended to increase when the test temperature was lowered below 30 C. The increased resistance was greater with spheroplasts from cells grown at 15 C. Cations, especially Ca(2+), protected spheroplasts against osmotic lysis. In general, the protective effects, measured at 30 C, were smaller with spheroplasts from cells grown at 15 C compared with 30 C. Citrate and ethylenediaminetetraacetate (EDTA) decreased the resistance of spheroplasts to osmotic lysis. On the whole, the decrease was greater with spheroplasts from cells grown at 30 C rather than 15 C. In the presence of EDTA, spheroplasts from cells grown at 30 C were less resistant to osmotic lysis at 5 C than at 30 C; when spheroplasts from cells grown at 15 C were similarly examined, they were more resistant to lysis at 5 C than at 30 C. Spheroplast membranes from cells grown at 15 C had slightly but significantly greater contents of Mg(2+), Ca(2+), K(+), and Na(+) compared with spheroplast membranes from cells grown at 15 C. Mg(2+) and Ca(2+) were more easily extracted with EDTA from membranes of 30 C-grown cells than from 15 C-grown cells.
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Ladbrooke BD, Chapman D. Thermal analysis of lipids, proteins and biological membranes. A review and summary of some recent studies. Chem Phys Lipids 1969; 3:304-56. [PMID: 4905514 DOI: 10.1016/0009-3084(69)90040-1] [Citation(s) in RCA: 584] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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26
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27
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Strom R, Caiafa P, Modovì B, Fanelli AR. Effect of temperature on potassium - dependent stimulation of transcellular migration in normal and neoplastic cells. FEBS Lett 1969; 3:343-347. [PMID: 11947045 DOI: 10.1016/0014-5793(69)80174-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- R Strom
- Institute of Biological Chemistry, University of Rome, Rome, Italy
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Ladbrooke BD, Jenkinson TJ, Kamat VB, Chapman D. Physical studies of myelin. I. Thermal analysis. BIOCHIMICA ET BIOPHYSICA ACTA 1968; 164:101-9. [PMID: 5680287 DOI: 10.1016/0005-2760(68)90076-3] [Citation(s) in RCA: 89] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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29
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30
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Reiss-Husson F. [Structure of liquid-crystalline phases of different phospholipids, monoglycerides, sphingolipids in the absence or presence of water]. J Mol Biol 1967; 25:363-82. [PMID: 6035283 DOI: 10.1016/0022-2836(67)90192-1] [Citation(s) in RCA: 336] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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31
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Reiss-Husson F, Luzzati V. Phase transitions in lipids in relation to the structure of membranes. ADVANCES IN BIOLOGICAL AND MEDICAL PHYSICS 1967; 11:87-107. [PMID: 4860236 DOI: 10.1016/b978-1-4832-3107-5.50007-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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32
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33
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Chapman D, Fluck DJ. Physical studies of phospholipids. 3. Electron microscope studies of some pure fully saturated 2,3-diacyl-DL-phosphatidyl-ethanolamines and phosphatidyl-cholines. J Cell Biol 1966; 30:1-11. [PMID: 4165077 PMCID: PMC2106989 DOI: 10.1083/jcb.30.1.1] [Citation(s) in RCA: 122] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
On heating pure, fully saturated 2,3-diacyl-DL-phosphatidyl-ethanolamines and 2,3-diacylphosphatidyl-cholines (lecithins) in water to the transition temperature at which large endothermic heat changes occur, they are observed, by light microscopy, to form myelin figures. This result is discussed in terms of the large difference in the transition temperature for "melting" of the hydrocarbon chains of unsaturated and saturated phospholipids and is illustrated by means of differential thermal analysis (D.T.A.) curves. These structures have been examined by electron microscopy after negative staining and after reaction with osmium tetroxide. Typical phospholipid lamella structures are seen in the phosphatidylcholines after negative staining, and in the phosphatidyl-ethanolamines after both negative staining and osmium fixation. The distances across these lamellae have been measured. Some preliminary investigations of the nature of the osmium tetroxide reaction with the phosphatidyl-ethanolamines have been made.
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Chapman D, Owens NF, Walker DA. Physical studies of phospholipids. II. Monolayer studies of some synthetic 2,3-diacyl-DL-phosphatidylethanolamines and phosphatidylcholines containing trans double bonds. BIOCHIMICA ET BIOPHYSICA ACTA 1966; 120:148-55. [PMID: 5961099 DOI: 10.1016/0926-6585(66)90286-x] [Citation(s) in RCA: 102] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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35
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