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Kejžar J, Mrak P, Osojnik Črnivec IG, Poklar Ulrih N. Influence of archaeal lipids isolated from Aeropyrum pernix K1 on physicochemical properties of sphingomyelin-cholesterol liposomes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184374. [PMID: 39053569 DOI: 10.1016/j.bbamem.2024.184374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 07/17/2024] [Accepted: 07/19/2024] [Indexed: 07/27/2024]
Abstract
We investigated the influence of archaeal lipids (C25,25) isolated from thermophilic archaeon Aeropyrum pernix K1 on physicochemical properties of liposomes comprised of egg sphingomyelin (SM) and cholesterol (CH) using fluorescence emission anisotropy, calcein release studies, dynamic light scattering, transmission electron microscopy and phase analysis light scattering. The 2 mol% addition of archaeal lipids enabled formation of small unilamellar vesicles by sonication while also having significant effect on reducing mean size, polydispersity index and zeta potential of C25,25/SM/CH vesicles. Increasing the ratio of C25,25 lipids in mixture of C25,25/SM/CH decreased lipid ordering parameter in dose dependent manner at different temperatures. We also demonstrated that adding 15 mol% C25,25 to SM/CH mixture will cause it to notably interact with fetal bovine serum which could make them a viable alternative adjuvant to synthetic ether-linked lipids in development of advanced liposomal vaccine delivery systems. The prospect of combining the proven strengths of SM/CH mixtures with the unique properties of C25,25 opens exciting possibilities for advancing drug delivery technologies, promising to yield formulations that are both highly effective and adaptable to a range of therapeutic applications.
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Affiliation(s)
- Jan Kejžar
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
| | - Polona Mrak
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, SI-1000 Ljubljana, Slovenia
| | - Ilja Gasan Osojnik Črnivec
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
| | - Nataša Poklar Ulrih
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia; The Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CipKeBiP), Jamova 39, SI-1000, Ljubljana, Slovenia.
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Babunagappan KV, Seetharaman A, Ariraman S, Santhosh PB, Genova J, Ulrih NP, Sudhakar S. Doxorubicin loaded thermostable nanoarchaeosomes: a next-generation drug carrier for breast cancer therapeutics. NANOSCALE ADVANCES 2024; 6:2026-2037. [PMID: 38633044 PMCID: PMC11019490 DOI: 10.1039/d3na00953j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 12/08/2023] [Indexed: 04/19/2024]
Abstract
Breast cancer has a poor prognosis due to the toxic side effects associated with high doses of chemotherapy. Liposomal drug encapsulation has resulted in clinical success in enhancing chemotherapy tolerability. However, the formulation faces severe limitations with a lack of colloidal stability, reduced drug efficiency, and difficulties in storage conditions. Nanoarchaeosomes (NA) are a new generation of highly stable nanovesicles composed of the natural ether lipids extracted from archaea. In our study, we synthesized and characterized the NA, evaluated their colloidal stability, drug release potential, and anticancer efficacy. Transmission electron microscopy images have shown that the NA prepared from the hyperthermophilic archaeon Aeropyrum pernix K1 was in the size range of 61 ± 3 nm. The dynamic light scattering result has confirmed that the NA were stable at acidic pH (pH 4) and high temperature (70 °C). The NA exhibited excellent colloidal stability for 50 days with storage conditions at room temperature. The cell viability results have shown that the pure NA did not induce cytotoxicity in NIH 3T3 fibroblast cells and are biocompatible. Then NA were loaded with doxorubicin (NAD), and FTIR and UV-vis spectroscopy results have confirmed high drug loading efficiency of 97 ± 1% with sustained drug release for 48 h. The in vitro cytotoxicity studies in MCF-7 breast cancer cell lines showed that NAD induced cytotoxicity at less than 10 nM concentration. Fluorescence-activated cell sorting (FACS) results confirmed that NAD induced late apoptosis in nearly 92% of MCF-7 cells and necrosis in the remaining cells with cell cycle arrest at the G0/G1 phase. Our results confirmed that the NA could be a potential next-generation carrier with excellent stability, high drug loading efficiency, sustained drug release ability, and increased therapeutic efficacy, thus reducing the side effects of conventional drugs.
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Affiliation(s)
| | - Abirami Seetharaman
- Department of Applied Mechanics and Biomedical Engineering, Indian Institute of Technology Madras Chennai India
| | - Subastri Ariraman
- Department of Applied Mechanics and Biomedical Engineering, Indian Institute of Technology Madras Chennai India
| | - Poornima Budime Santhosh
- Institute of Solid State Physics, Bulgarian Academy of Sciences Tzarigradsko Chausee Sofia Bulgaria
| | - Julia Genova
- Institute of Solid State Physics, Bulgarian Academy of Sciences Tzarigradsko Chausee Sofia Bulgaria
| | - Natasa Poklar Ulrih
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana Ljubljana Slovenia
| | - Swathi Sudhakar
- Department of Applied Mechanics and Biomedical Engineering, Indian Institute of Technology Madras Chennai India
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Kejžar J, Osojnik Črnivec IG, Poklar Ulrih N. Advances in Physicochemical and Biochemical Characterization of Archaeosomes from Polar Lipids of Aeropyrum pernix K1 and Stability in Biological Systems. ACS OMEGA 2023; 8:2861-2870. [PMID: 36713696 PMCID: PMC9878630 DOI: 10.1021/acsomega.2c07406] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 12/29/2022] [Indexed: 06/18/2023]
Abstract
Archaeosomes are vesicles made from archaeal lipids. They are characterized by remarkable thermostability, resistance to enzymatic degradation, long-term stability, and immunomodulatory properties. In this review the current status of physicochemical properties of archaeal lipids and their stability in biological systems is presented, focusing on total polar lipids from Aeropyrum pernix K1. The isolated total polar lipids from Aeropyrum pernix K1 consist exclusively of glycerol ether lipids with isoprenoid groups attached to glycerol via ether linkages. More specifically, the two major polar lipids extracted from the membranes are C25,25-achaetidyl(glucosyl)inositol and C25,25-achaetidylinositol. An overview of the results of the effects of temperature and pH on the stability, structural organization, fluidity, and permeability of archaeosomes composed of pure C25,25 was examined by a combination of techniques, including fluorescence emission spectroscopy, electron paramagnetic resonance, differential scanning calorimetry, and confocal microscopy. We also compared the physicochemical properties of pure vesicles composed of either archaeal lipids or conventional lipids (e.g., 1,2-dipalmitoyl-sn-glycero-3-phosphocholine) with mixed vesicles composed of both lipid types. Archaeal lipids are discussed in terms of their potential use as a targeted drug delivery system based on the results of in vivo and cytotoxicity studies.
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Affiliation(s)
- Jan Kejžar
- Department
of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
| | - Ilja Gasan Osojnik Črnivec
- Department
of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
| | - Nataša Poklar Ulrih
- Department
of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
- The
Centre of Excellence for Integrated Approaches in Chemistry and Biology
of Proteins (CipKeBiP), Jamova 39, SI-1000 Ljubljana, Slovenia
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Rezelj S, Kozorog M, Švigelj T, Ulrih NP, Žnidaršič N, Podobnik M, Anderluh G. Cholesterol Enriched Archaeosomes as a Molecular System for Studying Interactions of Cholesterol-Dependent Cytolysins with Membranes. J Membr Biol 2018; 251:491-505. [DOI: 10.1007/s00232-018-0018-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 02/05/2018] [Indexed: 12/31/2022]
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Vicedo E, Schlessinger A, Rost B. Environmental Pressure May Change the Composition Protein Disorder in Prokaryotes. PLoS One 2015; 10:e0133990. [PMID: 26252577 PMCID: PMC4529154 DOI: 10.1371/journal.pone.0133990] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 07/03/2015] [Indexed: 12/24/2022] Open
Abstract
Many prokaryotic organisms have adapted to incredibly extreme habitats. The genomes of such extremophiles differ from their non-extremophile relatives. For example, some proteins in thermophiles sustain high temperatures by being more compact than homologs in non-extremophiles. Conversely, some proteins have increased volumes to compensate for freezing effects in psychrophiles that survive in the cold. Here, we revealed that some differences in organisms surviving in extreme habitats correlate with a simple single feature, namely the fraction of proteins predicted to have long disordered regions. We predicted disorder with different methods for 46 completely sequenced organisms from diverse habitats and found a correlation between protein disorder and the extremity of the environment. More specifically, the overall percentage of proteins with long disordered regions tended to be more similar between organisms of similar habitats than between organisms of similar taxonomy. For example, predictions tended to detect substantially more proteins with long disordered regions in prokaryotic halophiles (survive high salt) than in their taxonomic neighbors. Another peculiar environment is that of high radiation survived, e.g. by Deinococcus radiodurans. The relatively high fraction of disorder predicted in this extremophile might provide a shield against mutations. Although our analysis fails to establish causation, the observed correlation between such a simplistic, coarse-grained, microscopic molecular feature (disorder content) and a macroscopic variable (habitat) remains stunning.
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Affiliation(s)
- Esmeralda Vicedo
- TUM, Department of Informatics, Bioinformatics & Computational Biology—i12, Boltzmannstr. 3, 85748 Garching, Munich, Germany
- TUM Graduate School of Information Science in Health (GSISH), Boltzmannstr. 11, 85748 Garching, Munich, Germany
- * E-mail:
| | - Avner Schlessinger
- Icahn School of Medicine at Mount Sinai, Department of Pharmacology and Systems Therapeutics, One Gustave L. Levy Place, Box 1603, New York, New York, 10029, United States of America
| | - Burkhard Rost
- TUM, Department of Informatics, Bioinformatics & Computational Biology—i12, Boltzmannstr. 3, 85748 Garching, Munich, Germany
- Institute of Advanced Study (TUM-IAS), Lichtenbergstr. 2a, 85748 Garching, Munich, Germany
- Institute for Food and Plant Sciences WZW Weihenstephan, Alte Akademie 8, Freising, Germany
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Šnajder M, Mihelič M, Turk D, Ulrih NP. Codon optimisation is key for pernisine expression in Escherichia coli. PLoS One 2015; 10:e0123288. [PMID: 25856104 PMCID: PMC4391949 DOI: 10.1371/journal.pone.0123288] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 02/17/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Pernisine is an extracellular serine protease from the hyperthermophilic Archaeon Aeropyrum pernix K1. Low yields from the natural host and expression problems in heterologous hosts have limited the potential applications of pernisine in industry. METHODOLOGY/ PRINCIPAL FINDINGS The challenges of pernisine overexpression in Escherichia coli were overcome by codon preference optimisation and de-novo DNA synthesis. The following forms of the pernisine gene were cloned into the pMCSGx series of vectors and expressed in E. coli cells: wild-type (pernisinewt), codon-optimised (pernisineco), and codon-optimised with a S355A mutation of a predicted active site (pernisineS355Aco). The fusion-tagged pernisines were purified using fast protein liquid chromatography equipped with Ni2+ chelate and gel filtration chromatography columns. The identities of the resultant proteins were confirmed with N-terminal sequencing, tandem mass spectrometry analysis, and immunodetection. Pernisinewt was not expressed in E. coli at detectable levels, while pernisineco and pernisineS355Aco were expressed and purified as 55-kDa proforms with yields of around 10 mg per litre E. coli culture. After heat activation of purified pernisine, the proteolytic activity of the mature pernisineco was confirmed using zymography, at a molecular weight of 36 kDa, while the mutant pernisineS355Aco remained inactive. Enzymatic performances of pernisine evaluated under different temperatures and pHs demonstrate that the optimal enzymatic activity of the recombinant pernisine is ca. 100°C and pH 7.0, respectively. CONCLUSIONS/ SIGNIFICANCE These data demonstrate that codon optimisation is crucial for pernisine overexpression in E. coli, and that the proposed catalytic Ser355 has an important role in pernisine activity, but not in its activation process. Pernisine is activated by autoproteolytical cleavage of its N-terminal proregion. We have also confirmed that the recombinant pernisine retains the characteristics of native pernisine, as a calcium modulated thermostable serine protease.
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Affiliation(s)
- Marko Šnajder
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Marko Mihelič
- Centre of Excellence for Integrated Approaches in Chemistry and Biology (CipKeBiP), Ljubljana, Slovenia
- Institute Jozef Stefan, Ljubljana, Slovenia
| | - Dušan Turk
- Centre of Excellence for Integrated Approaches in Chemistry and Biology (CipKeBiP), Ljubljana, Slovenia
- Institute Jozef Stefan, Ljubljana, Slovenia
| | - Nataša Poklar Ulrih
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
- Centre of Excellence for Integrated Approaches in Chemistry and Biology (CipKeBiP), Ljubljana, Slovenia
- * E-mail:
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Bending elasticity modulus of giant vesicles composed of aeropyrum pernix k1 archaeal lipid. Life (Basel) 2015; 5:1101-10. [PMID: 25821933 PMCID: PMC4500131 DOI: 10.3390/life5021101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Revised: 03/08/2015] [Accepted: 03/19/2015] [Indexed: 01/11/2023] Open
Abstract
Thermally induced shape fluctuations were used to study elastic properties of giant vesicles composed of archaeal lipids C25,25-archetidyl (glucosyl) inositol and C25,25-archetidylinositol isolated from lyophilised Aeropyrum pernix K1 cells. Giant vesicles were created by electroformation in pure water environment. Stroboscopic illumination using a xenon flash lamp was implemented to remove the blur effect due to the finite integration time of the camera and to obtain an instant picture of the fluctuating vesicle shape. The mean weighted value of the bending elasticity modulus kc of the archaeal membrane determined from the measurements meeting the entire set of qualification criteria was (1.89 ± 0.18) × 10−19 J, which is similar to the values obtained for a membrane composed of the eukaryotic phospholipids SOPC (1.88 ± 0.17) × 10−19 J and POPC (2.00 ± 0.21) × 10−19 J. We conclude that membranes composed of archaeal lipids isolated from Aeropyrum pernix K1 cells have similar elastic properties as membranes composed of eukaryotic lipids. This fact, together with the importance of the elastic properties for the normal circulation through blood system, provides further evidence in favor of expectations that archaeal lipids could be appropriate for the design of drug delivery systems.
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Polak A, Tarek M, Tomšič M, Valant J, Ulrih NP, Jamnik A, Kramar P, Miklavčič D. Electroporation of archaeal lipid membranes using MD simulations. Bioelectrochemistry 2014; 100:18-26. [DOI: 10.1016/j.bioelechem.2013.12.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 12/24/2013] [Accepted: 12/31/2013] [Indexed: 12/13/2022]
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Polak A, Tarek M, Tomšič M, Valant J, Ulrih NP, Jamnik A, Kramar P, Miklavčič D. Structural properties of archaeal lipid bilayers: small-angle X-ray scattering and molecular dynamics simulation study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:8308-8315. [PMID: 25000416 DOI: 10.1021/la5014208] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Aeropyrum pernix is an aerobic hyperthermophilic archaeon that grows in harsh environmental conditions and as such possesses unique structural and metabolic features. Its membrane interfaces with the extreme environment and is the first line of defense from external factors. Therefore, lipids composing this membrane have special moieties that increase its stability. The membrane of A. pernix is composed predominantly of two polar lipids 2,3-di-O-sesterterpanyl-sn-glicerol-1-phospho-1'(2'-O-α-D-glucosyl)-myo-inositol (AGI) and 2,3-di-O-sesterterpanyl-sn-glicerol-1-phospho-myo-inositol (AI). Both have methyl branches in their lipid tails and ether linkages and carbohydrates in their headgroup. These moieties significantly affect the structure and dynamics of the bilayer. To provide a molecular level insight into these characteristics, we used here Molecular Dynamics (MD) simulations of lipid bilayers of composition similar to those of the archaeal membranes. First, we show that the electron density profiles along the normal to the bilayers derived from the simulations are in good agreement with the profiles obtained by the small-angle X-ray scattering (SAXS) technique, which provides confidence in the force fields used. Analyses of the simulation data show that the archaeal lipid bilayers are less hydrated than conventional phosphatidylcholine (PC) lipids and that their structure is not affected by the salt present in the surrounding solution. Furthermore, the lateral pressure in their hydrophobic core, due to the presence of the branched tails, is much higher than that at PC-based lipid bilayers. Both the methyl branched tails and the special headgroup moieties contribute to slow drastically the lateral diffusion of the lipids. Furthermore, we found that the lipid head groups associate via hydrogen bonding, which affects their reorientational dynamics. All together, our data provide links between the microscopic properties of these membranes and their overall stability in harsh environments.
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Affiliation(s)
- Andraž Polak
- Faculty of Electrical Engineering, University of Ljubljana , Tržaška cesta 25, SI-1000 Ljubljana, Slovenia
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Santhosh PB, Penič S, Genova J, Iglič A, Kralj-Iglič V, Ulrih NP. A study on the interaction of nanoparticles with lipid membranes and their influence on membrane fluidity. ACTA ACUST UNITED AC 2012. [DOI: 10.1088/1742-6596/398/1/012034] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Šnajder M, Vilfan T, Černilec M, Rupreht R, Popović M, Juntes P, Šerbec VČ, Ulrih NP. Enzymatic degradation of PrPSc by a protease secreted from Aeropyrum pernix K1. PLoS One 2012; 7:e39548. [PMID: 22761822 PMCID: PMC3386259 DOI: 10.1371/journal.pone.0039548] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 05/22/2012] [Indexed: 11/18/2022] Open
Abstract
Background An R30 fraction from the growth medium of Aeropyrum pernix was analyzed for the protease that can digest the pathological prion protein isoform (PrPSc) from different species (human, bovine, deer and mouse). Methodology/Principal Findings Degradation of the PrPSc isoform by the R30 fraction and the purified protease was evaluated using the 6H4 anti-PrP monoclonal antibody. Fragments from the N-terminal and C-terminal of PrPSc were also monitored by Western blotting using the EB8 anti-PrP monoclonal antibody, and by dot blotting using the C7/5 anti-PrP monoclonal antibody, respectively. For detection of smaller peptides from incomplete digestion of PrPSc, the EB8 monoclonal antibody was used after precipitation with sodium phosphotungstate. Characterization of the purified active protease from the R30 fraction was achieved, through purification by fast protein liquid chromatography, and identification by tandem mass spectrometry the serine metalloprotease pernisine. SDS-PAGE and zymography show the purified pernisine plus its proregion with a molecular weight of ca. 45 kDa, and the mature purified pernisine as ca. 23 kDa. The purified pernisine was active between 58°C and 99°C, and between pH 3.5 and 8.0. The temperature and pH optima of the enzymatic activity of the purified pernisine in the presence of 1 mM CaCl2 were 105°C ±0.5°C and pH 6.5±0.2, respectively. Conclusions/Significance Our study has identified and characterized pernisine as a thermostable serine metalloprotease that is secreted from A. pernix and that can digest the pathological prion protein PrPSc.
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Affiliation(s)
- Marko Šnajder
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Tanja Vilfan
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Maja Černilec
- Blood Transfusion Center of Slovenia, Ljubljana, Slovenia
| | - Ruth Rupreht
- Blood Transfusion Center of Slovenia, Ljubljana, Slovenia
| | - Mara Popović
- Medical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Polona Juntes
- Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia
| | | | - Nataša Poklar Ulrih
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
- Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CipKeBiP), Ljubljana, Slovenia
- * E-mail:
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Effect of growth medium pH of Aeropyrum pernix on structural properties and fluidity of archaeosomes. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2012; 2012:285152. [PMID: 22778670 PMCID: PMC3384975 DOI: 10.1155/2012/285152] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/30/2012] [Accepted: 04/13/2012] [Indexed: 11/17/2022]
Abstract
The influence of pH (6.0; 7.0; 8.0) of the growth medium of Aeropyrum pernix K1 on the structural organization and fluidity of archaeosomes prepared from a polar-lipid methanol fraction (PLMF) was investigated using fluorescence anisotropy and electron paramagnetic resonance (EPR) spectroscopy. Fluorescence anisotropy of the lipophilic fluorofore 1,6-diphenyl-1,3,5-hexatriene and empirical correlation time of the spin probe methylester of 5-doxylpalmitate revealed gradual changes with increasing temperature for the pH. A similar effect has been observed by using the trimethylammonium-6-diphenyl-1,3,5-hexatriene, although the temperature changes were much smaller. As the fluorescence steady-state anisotropy and the empirical correlation time obtained directly from the EPR spectra alone did not provide detailed structural information, the EPR spectra were analysed by computer simulation. This analysis showed that the archaeosome membranes are heterogeneous and composed of several regions with different modes of spin-probe motion at temperatures below 70°C. At higher temperatures, these membranes become more homogeneous and can be described by only one spectral component. Both methods indicate that the pH of the growth medium of A. pernix does not significantly influence its average membrane fluidity. These results are in accordance with TLC analysis of isolated lipids, which show no significant differences between PLMF isolated from A. pernix grown in medium with different pH.
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Gmajner D, Grabnar PA, Žnidarič MT, Štrus J, Šentjurc M, Ulrih NP. Structural characterization of liposomes made of diether archaeal lipids and dipalmitoyl-L-α-phosphatidylcholine. Biophys Chem 2011; 158:150-6. [DOI: 10.1016/j.bpc.2011.06.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 06/21/2011] [Accepted: 06/21/2011] [Indexed: 11/15/2022]
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Gmajner D, Ota A, Šentjurc M, Ulrih NP. Stability of diether C25,25 liposomes from the hyperthermophilic archaeon Aeropyrum pernix K1. Chem Phys Lipids 2011; 164:236-45. [DOI: 10.1016/j.chemphyslip.2011.01.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/26/2011] [Accepted: 01/26/2011] [Indexed: 11/25/2022]
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Identification of various substrate-binding proteins of the hyperthermophylic archaeon Aeropyrum pernix K1. World J Microbiol Biotechnol 2010. [DOI: 10.1007/s11274-010-0333-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Črnigoj M, Kostanjšek R, Kaletunç G, Poklar Ulrih N. Effect of different fluorescent dyes on thermal stability of DNA and cell viability of the hyperthermophilic archaeon Aeropyrum pernix. World J Microbiol Biotechnol 2008. [DOI: 10.1007/s11274-008-9717-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Milek I, Črnigoj M, Ulrih NP, Kaletunç G. In vivo characterization of thermal stabilities of Aeropyrum pernix cellular components by differential scanning calorimetry. Can J Microbiol 2007; 53:1038-45. [DOI: 10.1139/w07-069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Revival studies of Aeropyrum pernix show that the viability of cells and cell recovery after heat treatment depends on the temperature of treatment. Differential scanning calorimetry (DSC) is used to analyze the relative thermal stabilities of cellular components of A. pernix and to identify the cellular components responsible for the observed lag phase and reduced maximum growth following a heat treatment. DSC thermograms show 5 visible endothermic transitions with 2 major transitions. DSC analysis of isolated crude ribosomes aids the assignment of the 2 major peaks observed in whole-cell thermograms to denaturation of ribosomal structures. A comparison of partial and immediate full rescan thermograms of A. pernix whole cells indicates that both major peaks represent irreversible thermal transitions. A DNA peak is also identified in the whole-cell thermogram by comparison with the optical data of isolated pure DNA. DNA melting is shown to be irreversible in dilute solution, whereas it is partially reversible in whole cells, owing at least in part, to restricted volume effects. In contrast to mesophilic organisms, hyperthermophilic A. pernix ribosomes are more thermally stable than DNA, but in both organisms, irreversible changes leading to cell death occur owing to ribosomal denaturation.
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Affiliation(s)
- Igor Milek
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
- Department of Food, Agricultural and Biological Engineering, 590 Woody Hayes Drive, The Ohio State University, Columbus, OH 43210-1057, USA
| | - Miha Črnigoj
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
- Department of Food, Agricultural and Biological Engineering, 590 Woody Hayes Drive, The Ohio State University, Columbus, OH 43210-1057, USA
| | - Nataša Poklar Ulrih
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
- Department of Food, Agricultural and Biological Engineering, 590 Woody Hayes Drive, The Ohio State University, Columbus, OH 43210-1057, USA
| | - Gönül Kaletunç
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
- Department of Food, Agricultural and Biological Engineering, 590 Woody Hayes Drive, The Ohio State University, Columbus, OH 43210-1057, USA
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Ulrih NP, Adamlje U, Nemec M, Sentjurc M. Temperature- and pH-Induced Structural Changes in the Membrane of the Hyperthermophilic Archaeon Aeropyrum pernix K1. J Membr Biol 2007; 219:1-8. [PMID: 17713807 DOI: 10.1007/s00232-007-9061-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Accepted: 06/20/2007] [Indexed: 11/28/2022]
Abstract
The influence of pH and temperature on the structural organization, fluidity and permeability of the hyperthermophilic archaeon membrane was investigated in situ by a combination of electron paramagnetic resonance (EPR) and fluorescence emission spectroscopy. For EPR measurements, Aeropyrum pernix cells, after growing at different pHs, were spin-labeled with the doxyl derivative of palmitic acid methylester (MeFASL(10,3)). From the EPR spectra maximal hyperfine splitting (2A (max)) and empirical correlation time (tau (emp)), which are related to mean membrane fluidity, were determined. The mean membrane fluidity increases with temperature and depends on the pH of the growth medium. Computer simulation of the EPR spectra shows that membrane of A. pernix is heterogeneous and consists of the regions characterized with three different types of motional characteristics, which define three types of membrane domains. Order parameter and proportion of the spin probes in the three types of domains define mean membrane fluidity. The fluidity changes of the membrane with pH and temperature correlate well with the ratio between the fluorescence emission intensity of the first and third bands in the vibronic spectra of pyrene, I(1)/I(3). At pH 7.0 a decrease of I(1)/I(3) from 2.0 to 1.2, due to the penetration of pyrene into the nonpolar membrane region, is achieved at temperatures above 65 degrees C, the lower temperature limit of A. pernix growth.
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Affiliation(s)
- Natasa Poklar Ulrih
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 1001, 1000 Ljubljana, Slovenia.
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Rodionov DA, Kurnasov OV, Stec B, Wang Y, Roberts MF, Osterman AL. Genomic identification and in vitro reconstitution of a complete biosynthetic pathway for the osmolyte di-myo-inositol-phosphate. Proc Natl Acad Sci U S A 2007; 104:4279-84. [PMID: 17360515 PMCID: PMC1838593 DOI: 10.1073/pnas.0609279104] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Indexed: 11/18/2022] Open
Abstract
Di-myo-inositol 1,1'-phosphate (DIP) is a major osmoprotecting metabolite in a number of hyperthermophilic species of archaea and bacteria. Although the DIP biosynthesis pathway was previously proposed, genes encoding only two of the four required enzymes, inositol-1-phosphate synthase and inositol monophosphatase, were identified. In this study we used a comparative genomic analysis to predict two additional genes of this pathway (termed dipA and dipB) that remained missing. In Thermotoga maritima both candidate genes (in an originally misannotated locus TM1418) form an operon with the inositol-1-phosphate synthase encoding gene (TM1419). A predicted inositol-mono-phosphate cytidylyltransferase activity was directly confirmed for the purified product of T. maritima gene dipA cloned and expressed in Escherichia coli. The entire DIP pathway was reconstituted in E. coli by cloning of the TM1418-TM1419 operon in pBAD expression vector and confirmed to function in the crude lysate. (31)P NMR and MS analysis revealed that DIP synthesis proceeds via a phosphorylated DIP intermediate, P-DIP, which is generated by the dipB-encoded enzyme, now termed P-DIP synthase. This previously unknown intermediate is apparently converted to the final product, DIP, by an inositol monophosphatase-like phosphatase. These findings allowed us to revise the previously proposed DIP pathway. The genomic survey confirmed its presence in the species known to use DIP for osmoprotection. Among several newly identified species with a postulated DIP pathway, Aeropyrum pernix was directly proven to produce this osmolyte.
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Affiliation(s)
- Dmitry A. Rodionov
- *Burnham Institute for Medical Research, La Jolla, CA 92037
- Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow 127994, Russia; and
| | | | - Boguslaw Stec
- *Burnham Institute for Medical Research, La Jolla, CA 92037
| | - Yan Wang
- Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467; and
| | - Mary F. Roberts
- Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467; and
| | - Andrei L. Osterman
- *Burnham Institute for Medical Research, La Jolla, CA 92037
- Fellowship for Interpretation of Genomes, Burr Ridge, IL 60527
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