Georgi Kostov, Dipl. Eng., Research Associate

Radka Vladkova, Research Associate, PhD

Rada Mutafchieva, Research Associate, PhD

Borislav Angelov, Research Associate, PhD

Svetla Todinova, Dipl. Eng., Research Associate

Albena Jordanova, Research Associate

Nezabravka Nikolaeva, Dipl. Eng. Chem.

Associated members

Acad. Boris Tenchov

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Periodic minimal surface of Pn3m cubic symmetry

View of Pn3m cubic node

View of Im3m cubic node

Structure, thermodynamics, and polymorphism of lipid membranes and lipid-water systems. Phase transitions and phase diagrams of lipid mixtures. Formation of nonlamellar lipid phases. Formation of monolayers and bilayer foam films from lamellar and nonlamellar liquid crystalline lipid phases. Transformations and morphology of giant (cell-sized) unilamellar lipid vesicles. Regulation of lipid membrane phase state. Mechanisms of membrane cryodamage and cryoprotection. Thermodynamics and stability of biopolymers, detergent-nonlamellar lipid phases and biomembrane fragments. Foam model of proteins. Lipid membrane interactions with natural and synthetic bioactive molecules.

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High-sensitivity differential adiabatic scanning microcalorimetry, differential scanning densitometry, phase-contrast and fluorescent microscopy with temperature control and high-sensitivity image processing, micromanipulation of individual lipid vesicles and cells, stationary and time-resolved fluorescence spectroscopy, methods for preparation and control of lipid dispersions, monolayers and bilayer foam films.

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Tenchov B, Boyanov A, Koynova R (1984) Lyotropic polymorphism of racemic DPPE. A differential scanning calorimetry study. Biochemistry US 23, 3553-3558. 

Mutafchieva R, Panaiotov I, Dimitrov D (1984) Surface pressure hysteresis of mixed lipid-protein monolayers: application to the alveolar dynamics. Z. Naturforsch. 39C, 965-971.

Tenchov B (1985) Nonuniform lipid distribution in membranes. Prog. Surface Sci. 20, 273-340. 

Boyanov AI, Koynova RD, Tenchov BG. (1986) Effect of lipid admixtures on the L-dipalmitoylphosphatidylcholine subtransition. Chem. Phys. Lipids. 39, 155-63.

Koynova R, Tenchov B, Quinn P (1989) Sugars favor formation of hexagonal phase at the expense of the lamellar liquid-crystalline phase in hydrated phosphatidylethanolamines. Biochim. Biophys. Acta 980, 377-380. 

Tenchov B, Yao H, Hatta I (1989) Time-resolved X-ray diffraction and calorimetric studies at low scan rates. I. Fully hydrated DPPC and DPPC/water/ethanol phases. Biophys. J. 56, 757-768. 

Tenchov B (1991) On the reversibility of the phase transitions in lipid-water systems. Chem. Phys. Lipids 57, 165-179. 

Koynova R, Tenchov B, Todinova S, Quinn P (1995) Rapid reversible formation of a metastable subgel phase in saturated diacylphosphatidylcholines. Biophys. J. 68, 2370-2375.

Koynova R, Brankov J, Tenchov B (1997) Modulation of the lipid phase behaviour by kosmotropic and chaotropic solutes. Experiment and thermodynamic theory. Eur. Biophys. J. 25, 261-274. reprint request

Tenchov B, Koynova R, Rapp G (1998) Accelerated formation of cubic phases in phosphatidylethanolamine dispersions. Biophys. J. 75, 853-866.  reprint request

Koynova R, Caffrey M (1998) Phases and phase transitions of the phosphatidylcholines. Biochim. Biophys. Acta 1376, 91-145. reprint request

Koynova R, Tenchov B, Rapp G (1999) Effect of PEG-lipid conjugates on the phase behavior of phosphatidylethanolamine dispersions. Colloids & Surfaces A 149, 571-575.

Tenchov B, Koynova R, Rappolt M, Rapp G (1999) An ordered metastable phase in hydrated phosphatidylethanolamine: The Y-transition. Biochim. Biophys. Acta 1417, 183-190. reprint request

Wolf C, Quinn P, Koumanov K, Chachaty C, Tenchov B (1999) Physical arrangement of membrane lipids susceptible to being used in the process of cell sorting of proteins. J. Soc. Biol. 193, 117-23.

Angelova MI, Mutafchieva R, Dimova R, Tenchov B (1999) Shape transformations of giant unilamellar vesicles induced by ethanol and temperature variations. Colloids & Surfaces A 149, 201-205.

Angelov B, Ollivon M, Angelova A (1999) X-ray diffraction study of the effect of the detergent octyl glucoside on the structure of lamellar and nonlamellar lipid/water phases of use for membrane protein reconstitution. Langmuir 15, 8225-8234.

Alexandrova L, Koynova R, Grigorov L, Tenchov B (1999) Singular behavior of the three-phase contact between DMPC dispersion, air and quartz at the critical temperature of 29°C. Colloids & Surfaces A149, 239-244.

Vladkova R (2000) Chlorophyll a self-assembly in polar solvent–water mixtures. Photochem. Photobiol. 71, 71-83. reprint request 

Komsa-Penkova R, Koynova R, Kostov G, Tenchov B (2000) Discrete reduction of type I collagen thermal stability upon oxidation. Biophys. Chem. 83, 185-195.

Vladkova R, Teuchner K, Leupold D, Koynova R, Tenchov B (2000) Detection of the metastable rippled gel phase in hydrated phosphatidylcholine by fluorescence spectroscopy. Biophys. Chem. 84, 159-166.

Tenchov B, Koynova R, Rapp G (2001) New ordered metastable phases between the gel and subgel phases in hydrated phospholipids. Biophys. J. 80, 1873-1890. reprint request

Wolf C, Koumanov K, Quinn P, Tenchov B (2001) Cholesterol favors phase separation of sphingomyelin. Biophys. Chem. 89, 163-172.

Koynova R, Tenchov B (2001) Interactions of surfactants and fatty acids with lipids. Current Opinion Colloid Interface Sci. 6, 277-286.

Angelov B, Sadoc JF, Jullien R, Soyer A, Mornon JP, Chomilier J (2002) Nonatomic solvent-driven Voronoi tessellation of proteins: An open tool to analyze protein folds. Proteins: Structure, Function & Genetics 49, 446-456.

Angelov B (2002) Protein nanodomain patterns in lipidic bicontinuous cubic phases. Mod. Phys. Lett. B 16, 225-230.

Koynova R, Caffrey M (2002) An index of lipid phase diagrams. Chem. Phys. Lipids 115, 107-219.

Angelov B, Angelova A, Ollivon M, Bourgaux C, Campitelli A (2003) Diamond-type lipid cubic phase with large water channels. J. Am. Chem. Soc. 125, 7188-7189.

Koynova R, MacDonald RC (2003) Mixtures of Cationic Lipid O-ethylphosphatidylcholine with Membrane Lipids and DNA: Phase Diagrams. Biophys. J. 85, 2449-2465.

Koynova R, MacDonald RC (2003) Cationic O-ethylphosphatidylcholines and lipoplexes: phase behavior, structural organisation, morphology. Biochim. Biophys. Acta 1613, 39-48.

Valtcheva R, Stephanova E, Jordanova A, Pankov R, Altankov G, Lalchev Z (2003) Effect of halothane on lung carcinoma cells A 549. Chemico-Biological Interactions 146, 191-200.

Jordanova A, Lalchev Z, Tenchov B (2003) Formation of monolayers and bilayer foam films from lamellar, inverted hexagonal and cubic lipid phases. Eur. Biophys. J. 31, 626-632.

Parvanova K, Idakieva K, Todinova S, Genov N (2003) C-terminal functional unit of Rapana thomasiana (marine snail, gastropod) hemocyanin isoform RtH1: isolation and characterization. Biochim. Biophys. Acta - Proteins & Proteomics 1651, 153-162.

Dobrikova AG, Varkonyi Z, Krumova SB, Kovacs L, Kostov GK, Todinova SJ, Busheva MC, Taneva SG, Garab G (2003) Structural Rearrangements in chloroplast thylakoid membranes revealed by differential scanning calorimetry and circular dichroism spectroscopy. Thermo-optic effect. Biochemistry 42, 11272-11280.

Koynova R, Rosenzweig HS, Wang L, Wasielewski M, MacDonald RC (2004) Novel fluorescent cationic phospholipid, O-4-napthylimido-1-butyl-DOPC, exhibits unusual foam morphology, forms hexagonal and cubic phases in mixtures, and transfects DNA. Chem. Phys. Lipids 129, 183-194. 

Christova N, Tuleva B, Lalchev Z, Jordanova A, Jordanov B (2004) Rhamnolipid biosurfactants produced by Renibacterium salmoninarum 27BN during growth on n-hexadecane. Z. Naturforsch. 59C, 70-74.

Lalchev Z, Georgiev G, Jordanova A, Todorov R, Christova E, Vassilieff CS (2004) A comparative study of exogenous surfactant preparations and tracheal aspirate: interfacial tensiometry and properties of foam films. Colloids & Surfaces B 33, 227-234.

Koynova R, MacDonald RC (2004) Columnar DNA superlattices in lamellar /O/-ethylphosphatidylcholine
lipoplexes. Nano Lett. 4, 1475-1479.

Tarahovsky YS, Koynova R, MacDonald RC (2004) DNA release from lipoplexes by anionic lipids: correlation with lipid mesomorphism, interfacial curvature, and membrane fusion. Biophys. J. 87, 1054-1064.

Holm JK, Krumova SB, Varkonyi Z, Todinova SJ, Rajagopal S, Posselt D, Taneva SG, Garab G (2004) Thermo-optically induced reversible reorganizations in LHCII. Significance of thermal instability, role of LHCII-only domains in thylakoids. Proceedings of 13th International Congress of Photosynthesis Montreal, Canada (P2B-8) (in press).

Krumova SB, Todinova SJ, Busheva MC, Taneva SG (2004) Kinetic nature of the thermal destabilization of LHCII macroaggregates. J. Photochem. Photobiol. B (in press).

Shosheva A, Donchev A, Dimitrov M, Kostov G, Toromanov G, Getov V, Alexov E (2004) Comparative study of the stability of poplar plastocyanin isoforms. Biochim. Biophys. Acta - Proteins and Proteomics (in press).

Franck D, Sadoc JF, Jullien R, Angelov B, Mornon JP (2004) Voro3D: 3D voronoi tessellations applied to protein structures. Bioinformatics (in press).