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Kis M, Szabó T, Tandori J, Maróti P. Roadmap of electrons from donor side to the reaction center of photosynthetic purple bacteria with mutated cytochromes. Photosynth Res 2024; 159:261-272. [PMID: 38032488 PMCID: PMC10991045 DOI: 10.1007/s11120-023-01059-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 10/28/2023] [Indexed: 12/01/2023]
Abstract
In photosynthetic bacteria, the absorbed light drives the canonical cyclic electron transfer between the reaction center and the cytochrome bc1 complexes via the pools of mobile electron carriers. If kinetic or structural barriers hinder the participation of the bc1 complex in the cyclic flow of electrons, then the pools of mobile redox agents must supply the electrons for the multiple turnovers of the reaction center. These conditions were achieved by continuous high light excitation of intact cells of bacterial strains Rba. sphaeroides and Rvx. gelatinosus with depleted donor side cytochromes c2 (cycA) and tetraheme cytochrome subunit (pufC), respectively. The gradual oxidation by ferricyanide further reduced the availability of electron donors to pufC. Electron transfer through the reaction center was tracked by absorption change and by induction and relaxation of the fluorescence of the bacteriochlorophyll dimer. The rate constants of the electron transfer (~ 3 × 103 s‒1) from the mobile donors of Rvx. gelatinosus bound either to the RC (pufC) or to the tetraheme subunit (wild type) were similar. The electrons transferred through the reaction center dimer were supplied entirely by the donor pool; their number amounted to about 5 in wild type Rvx. gelatinosus and decreased to 1 in pufC oxidized by ferricyanide. Fluorescence yield was measured as a function of the oxidized fraction of the dimer and its complex shape reveals the contribution of two competing processes: the migration of the excitation energy among the photosynthetic units and the availability of electron donors to the oxidized dimer. The experimental results were simulated and rationalized by a simple kinetic model of the two-electron cycling of the acceptor side combined with aperiodic one-electron redox function of the donor side.
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Affiliation(s)
- M Kis
- Balaton Limnological Research Institute, Klebelsberg K. Utca 3, Tihany, 8237, Hungary
| | - T Szabó
- Institute of Medical Physics, University of Szeged, Korányi Fasor 9, Szeged, 6720, Hungary
| | - J Tandori
- Institute of Medical Physics, University of Szeged, Korányi Fasor 9, Szeged, 6720, Hungary
| | - P Maróti
- Institute of Medical Physics, University of Szeged, Korányi Fasor 9, Szeged, 6720, Hungary.
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2
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Ekin T, Kis M, Gungoren F, Atici A, Kunak AÜ, Mutlu D, Katkat F, Demir M, Sarac İ, Soydan E, Karaduman M, Bekar L, Boyuk F, Adiyaman MS, Zoghi M. Awareness and knowledge of pneumococcal vaccination in cardiology outpatient clinics and impact of physicians' recommendation on vaccination rates. Eur J Prev Cardiol 2022. [PMCID: PMC9384017 DOI: 10.1093/eurjpc/zwac056.170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: None.
Background
Although there is not enough data on pneumococcal vaccination status in patients with cardiovascular disease and or risk factors in our country, it is known that vaccination rates are quite low in the current data.
Purpose
We aimed to evaluate the awareness of pneumococcal vaccination (PCV13, PPSV23) in general cardiology outpatient clinics and impact of physician’s recommendation (with educational brochures) on vaccination rate.
Methods
Awareness of vaccination, before COVID-19 pandemic, was measured in patients admitting to cardiology outpatient clinics from 40 center of our country by a questionnaire contained 19 questions. The demographics (including gender, age, educational level, awareness vaccination level) and comorbidities were obtained. The vaccination rates were calculated within 3-months follow-up from the admitting of patient to cardiology clinics.
Results
The 403 (18.2%) of patients with previous pneumococcal vaccination were excluded from the study. The mean age of study population (n=1808) was 61.9±12.1 years and 55.4% were male. The 58.7% had coronary artery disease, hypertension (74.1%) was the most common risk factor and 32.7% of the patients had never been vaccinated although they had information about vaccination before. The 98.5% were referred to family medicine (n=1412, 78.1%) or vaccination outpatient clinics (n=370, 20.5%) and the vaccination rate was 62.1% during the follow-up period. The differences between vaccinated and not-vaccinated patients are presented in Table 1.
The physician’s recommendation was positively correlated with vaccination intention and behavior in our participants. Multivariate logistic regression analysis showed a significant between vaccination and female sex [OR=1.55 (95% CI=1.25–1.92), p<0.001], higher education level [OR=1.49 (95% CI=1.15-1.92), p=0.002] patients’ knowledge [OR=1.93 (95% CI=1.56-2.40), p<0.001], and their physician’s recommendation [OR=5.12 (95% CI=1.92-13.68), p=0.001].
Conclusion
To our knowledge this is the first report about the awareness pneumococcal vaccination rates and impact of physician’s recommendation in patients with cardiovascular disease by high study population. These findings suggest providing information on the benefits of vaccination by physician’s and educational advice was significantly associated with an increase vaccination rate and have a key role.
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Affiliation(s)
- T Ekin
- Sorgun State Hospital, Cardiology, Yozgat, Turkey
| | - M Kis
- Dokuz Eylul University, Cardiology, Izmir, Turkey
| | | | - A Atici
- Medeniyet University, Istanbul, Turkey
| | - AÜ Kunak
- Medstar Hospital, Antalya, Turkey
| | - D Mutlu
- Istanbul University Cerrahpasa Faculty of Medicine, Istanbul, Turkey
| | - F Katkat
- Istanbul Education and Research Hospital, Istanbul, Turkey
| | - M Demir
- Kutahya Health Sciences University, Kutahya, Turkey
| | - İ Sarac
- Regional Training and Research Hospital, Erzurum, Turkey
| | | | | | - L Bekar
- HITIT UNIVERSITY, Corum, Turkey
| | - F Boyuk
- Yedikule Chest Diseases and Thoracic Surgery Training and Research Hospital, Istanbul, Turkey
| | - MS Adiyaman
- Gazi Yasargil Research Hospital, Diyarbakir, Turkey
| | - M Zoghi
- Ege University, Izmir, Turkey
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Dinc Asarcikli L, Kis M, Guvenc T, Tosun V, Acar B, Avci Demir F, Naser A, Zoghi M, Keles F, Usalp S, Aslanturk OF, Uygun T, Karamanlioglu M, Er F, Eliz Uzel K. Usefulness of novel martin/hopkins and sampson equations over friedewald equation in cardiology outpatient: CVSCORE-TR substudy. Eur J Prev Cardiol 2021. [DOI: 10.1093/eurjpc/zwab061.277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: None.
OnBehalf
CVSCORE-TR study group
Background
Friedewald equation (LDL-Cf) is known to produce inaccurate estimations of low-density lipoprotein cholesterol (LDL-C) when triglycerides are high (>400 mg/dl) or LDL-C is low (<70 mg/dl). Martin/Hopkins (LDL-Cmh) and Sampson (LDL-Cs) equations were developed to overcome these limitations, but few data are available whether these equations offer incremental usefulness over LDL-Cf.
Purpose
In this pragmatic study, we aimed to evaluate the agreement between LDL-C calculated using LDL-Cmh, LDL-Cs and LDL-Cf equations and to understand whether using LDL-Cmh or LDL-Cs instead of LDL-Cf leads to significant changes on the clinical decision-making
Methods
4196 cardiology outpatient cases that were included in a multicenter registry database were analyzed. Each case was assigned into a cardiovascular risk class using web-based SCORE (Systematic COronary Risk Evaluation) algorithm calibrated for high-risk European countries, and relevant European guidelines were used to assess LDL-C targets. LDL-Cf, LDL-Cs and LDL-Cmh were calculated as previously described.
Results
Compared to LDL-Cmh and LDL-Cs, LDL-Cf was able to correctly identify 96.9%-98.08% of cases as within or out of LDL-C target, respectively, while 1.95%-2.8% of cases were falsely identified as within LDL-C target. Kappa coefficients for agreement between LDL-Cf vs. LDL-Cmh and LDL-Cf vs. LDL-Cs were 0.868 and 0.918 (p < 0.001 for both). For patients not on anticholesterolemic drugs, decision to initiate treatment would be different in 1.2%-1.8% of cases if LDL-Cs or LDL-Cmh were used, respectively. For those already on anticholesterolemic drugs, decisions regarding to treatment intensification would be different in 1.5%-2.4% of cases if LDL-Cs or LDL-Cmh were used.
Conclusions
Friedewald equation had an excellent degree of agreement with the novel Martin/Hopkins and Sampson formulas in most cardiology outpatients, especially those within the lower end of the cardiovascular risk spectrum. In selected patients, especially those with high or very high risk in whom LDL-Cf < 70 mg/dl or those with a TG > 400 mg/dl, agreement was far worse and thus novel equations might have an incremental usefulness for clinical decision making.
Table 1 Reference Comparison Correct estimation Underestimation Overestimation Kappa (p value) All patients that were not on cholesterol-lowering treatment LDL-Cmh LDL-Cf 2785 (98.1%) 51 (1.8%) 3 (0.1%) 0.962 (<0.001) LDL-Cs LDL-Cf 2804 (98.8%) 35 (1.2%) 0 (0.0%) 0.975 (<0.001) Agreement for the indication of cholesterol-lowering treatment for patients not already on cholesterol-lowering drugs. Leftmost column shows the reference method, and the second row shows equation which is compared to the reference method.
Abstract Figure
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Affiliation(s)
- L Dinc Asarcikli
- Dr. Siyami Ersek Thoracic and Cardiovascular Surgery Center, Istanbul, Turkey
| | - M Kis
- Silopi State Hospital, Sirnak, Turkey
| | - T Guvenc
- Kirklareli University, Faculty of Medicine, Department of Cardiology, Kirklareli, Turkey
| | - V Tosun
- Sanliurfa Research and Educational Hospital, Department of Cardiology, Sanliurfa, Turkey
| | - B Acar
- Kocaeli University Hospital, Department of Cardiology, Kocaeli, Turkey
| | | | - A Naser
- Medical Park Hospital of Istanbul, Cardiology, Istanbul, Turkey
| | - M Zoghi
- Ege University, Cardiology, Izmir, Turkey
| | - F Keles
- Elazig Education and Research Hospital, Cardiology, Elazig, Turkey
| | - S Usalp
- Turhal State Hospital, Cardiology, Tokat, Turkey
| | | | - T Uygun
- Sanliurfa Research and Educational Hospital, Department of Cardiology, Sanliurfa, Turkey
| | | | - F Er
- Yuksek Ihtisas Hospital of Bursa, Cardiology, Bursa, Turkey
| | - K Eliz Uzel
- Adiyaman University Training and Research Hospital, Cardiology, Adiyaman, Turkey
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4
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Jahn D, Träger M, Kis M, Brabetz C, Schumacher D, Blažević A, Ciobanu M, Pomorski M, Bonnes U, Busold S, Kroll F, Brack FE, Schramm U, Roth M. Chemical-vapor deposited ultra-fast diamond detectors for temporal measurements of ion bunches. Rev Sci Instrum 2018; 89:093304. [PMID: 30278706 DOI: 10.1063/1.5048667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 09/09/2018] [Indexed: 06/08/2023]
Abstract
This article reports on the development of thin diamond detectors and their characterization for their application in temporal profile measurements of subnanosecond ion bunches. Two types of diamonds were used: a 20 μm thin polycrystalline chemical vapor deposited (CVD) diamond and a membrane with a thickness of (5 ± 1) μm etched out of a single crystal (sc) CVD diamond. The combination of a small detector electrode and an impedance matched signal outlet leads to excellent time response properties with a signal pulse resolution (FWHM) of τ = (113 ± 11) ps. Such a fast diamond detector is a perfect device for the time of flight measurements of MeV ions with bunch durations in the subnanosecond regime. The scCVD diamond membrane detector was successfully implemented within the framework of the laser ion generation handling and transport project, in which ion beams are accelerated via a laser-driven source and shaped with conventional accelerator technology. The detector was used to measure subnanosecond proton bunches with an intensity of 108 protons per bunch.
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Affiliation(s)
- D Jahn
- Institut für Kernphysik, Technische Universität Darmstadt, Schloßgartenstraße 9, D-64289 Darmstadt, Germany
| | - M Träger
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt, Germany
| | - M Kis
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt, Germany
| | - C Brabetz
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt, Germany
| | - D Schumacher
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt, Germany
| | - A Blažević
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt, Germany
| | - M Ciobanu
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt, Germany
| | - M Pomorski
- CEA-LIST, Diamond Sensors Laboratory, Gif-sur-Yvette F-91191, France
| | - U Bonnes
- Institut für Kernphysik, Technische Universität Darmstadt, Schloßgartenstraße 9, D-64289 Darmstadt, Germany
| | - S Busold
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt, Germany
| | - F Kroll
- Technische Universität Dresden, Mommsenstr. 13, 01069 Dresden, Germany
| | - F-E Brack
- Technische Universität Dresden, Mommsenstr. 13, 01069 Dresden, Germany
| | - U Schramm
- Technische Universität Dresden, Mommsenstr. 13, 01069 Dresden, Germany
| | - M Roth
- Institut für Kernphysik, Technische Universität Darmstadt, Schloßgartenstraße 9, D-64289 Darmstadt, Germany
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Skraqi E, Kis M, Akin M. P6371Endothelial functions are preserved in left distal radial access coronary angiography, a prospective comparison with right and left forearm radial artery access site. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy566.p6371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | - M Kis
- Ege University, Izmir, Turkey
| | - M Akin
- Ege University, Izmir, Turkey
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6
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Kóbori TO, Uzumaki T, Kis M, Kovács L, Domonkos I, Itoh S, Krynická V, Kuppusamy SG, Zakar T, Dean J, Szilák L, Komenda J, Gombos Z, Ughy B. Phosphatidylglycerol is implicated in divisome formation and metabolic processes of cyanobacteria. J Plant Physiol 2018; 223:96-104. [PMID: 29558689 DOI: 10.1016/j.jplph.2018.02.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 02/26/2018] [Accepted: 02/27/2018] [Indexed: 06/08/2023]
Abstract
Phosphatidylglycerol is an essential phospholipid for photosynthesis and other cellular processes. We investigated the role of phosphatidylglycerol in cell division and metabolism in a phophatidylglycerol-auxotrophic strain of Synechococcus PCC7942. Here we show that phosphatidylglycerol is essential for the photosynthetic electron transfer and for the oligomerisation of the photosynthetic complexes, notably, we revealed that this lipid is important for non-linear electron transport. Furthermore, we demonstrate that phosphatidylglycerol starvation elevated the expressions of proteins of nitrogen and carbon metabolism. Moreover, we show that phosphatidylglycerol-deficient cells changed the morphology, became elongated, the FtsZ ring did not assemble correctly, and subsequently the division was hindered. However, supplementation with phosphatidylglycerol restored the ring-like structure at the mid-cell region and the normal cell size, demonstrating the phosphatidylglycerol is needed for normal septum formation. Taken together, central roles of phosphatidylglycerol were revealed; it is implicated in the photosynthetic activity, the metabolism and the fission of bacteria.
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Affiliation(s)
- Tímea O Kóbori
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary; Doctoral School of Biology, University of Szeged, H-6726 Szeged, Hungary
| | - Tatsuya Uzumaki
- Center for Gene Research, Nagoya University, Furocyo, Chikusa, Nagoya 464-8607, Japan
| | - Mihály Kis
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary
| | - László Kovács
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary
| | - Ildikó Domonkos
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary
| | - Shigeru Itoh
- Center for Gene Research, Nagoya University, Furocyo, Chikusa, Nagoya 464-8607, Japan
| | - Vendula Krynická
- Institute of Microbiology, Center Algatech, Czech Academy of Sciences, Opatovický mlýn, 37981 Třeboň, Czech Republic
| | - Saravanan G Kuppusamy
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary
| | - Tomas Zakar
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary
| | - Jason Dean
- Institute of Microbiology, Center Algatech, Czech Academy of Sciences, Opatovický mlýn, 37981 Třeboň, Czech Republic
| | - László Szilák
- Institute of Biology, Savaria Campus, Eötvös Lorand University, Szombathely, H-9700, Hungary
| | - Josef Komenda
- Institute of Microbiology, Center Algatech, Czech Academy of Sciences, Opatovický mlýn, 37981 Třeboň, Czech Republic
| | - Zoltán Gombos
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary
| | - Bettina Ughy
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary.
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Vajravel S, Kovács L, Kis M, Rehman AU, Vass I, Gombos Z, Toth TN. β-Carotene influences the phycobilisome antenna of cyanobacterium Synechocystis sp. PCC 6803. Photosynth Res 2016; 130:403-415. [PMID: 27165097 DOI: 10.1007/s11120-016-0273-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 05/01/2016] [Indexed: 06/05/2023]
Abstract
We investigated the relation between the carotenoid composition and the structure of phycobilisome (PBS) antenna of cyanobacterium Synechocystis sp. PCC 6803. PBS is a large soluble protein complex enhances the light harvesting efficiency of the cells. It is composed of a central allophycocyanin core and radial phycocyanin rods, but it does not contain carotenoids. However, the absence or low level of carotenoids were previously shown to lead the co-existence of unconnected rod units and assembled PBS with shorter peripheral rods. Here we show that the lack of β-carotene, but not of xanthophylls or the distortion of photosystem structure, evoked unconnected rods. Thus, these essential β-carotene molecules are not bound by Photosystem I or Photosystem II. Our results do not show correlation between the reactive oxygen species (ROS) and PBS distortion despite the higher singlet oxygen producing capacity and light sensitivity of the mutant cells. Reduced cellular level of those linker proteins attaching the rod units together was also observed, but the direct damage of the linkers by ROS are not supported by our data. Enzymatic PBS proteolysis induced by nitrogen starvation in carotenoid mutant cells revealed a retarded degradation of the unconnected rod units.
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Affiliation(s)
- Sindhujaa Vajravel
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, P.O. Box 521, Szeged, 6701, Hungary
| | - László Kovács
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, P.O. Box 521, Szeged, 6701, Hungary
| | - Mihály Kis
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, P.O. Box 521, Szeged, 6701, Hungary
| | - Ateeq Ur Rehman
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, P.O. Box 521, Szeged, 6701, Hungary
| | - Imre Vass
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, P.O. Box 521, Szeged, 6701, Hungary
| | - Zoltan Gombos
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, P.O. Box 521, Szeged, 6701, Hungary
| | - Tunde N Toth
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, P.O. Box 521, Szeged, 6701, Hungary.
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Tóth TN, Chukhutsina V, Domonkos I, Knoppová J, Komenda J, Kis M, Lénárt Z, Garab G, Kovács L, Gombos Z, van Amerongen H. Carotenoids are essential for the assembly of cyanobacterial photosynthetic complexes. Biochimica et Biophysica Acta (BBA) - Bioenergetics 2015; 1847:1153-65. [DOI: 10.1016/j.bbabio.2015.05.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 05/26/2015] [Accepted: 05/29/2015] [Indexed: 01/15/2023]
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9
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Kopečná J, Pilný J, Krynická V, Tomčala A, Kis M, Gombos Z, Komenda J, Sobotka R. Lack of Phosphatidylglycerol Inhibits Chlorophyll Biosynthesis at Multiple Sites and Limits Chlorophyllide Reutilization in Synechocystis sp. Strain PCC 6803. Plant Physiol 2015; 169:1307-17. [PMID: 26269547 PMCID: PMC4587476 DOI: 10.1104/pp.15.01150] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 08/11/2015] [Indexed: 05/20/2023]
Abstract
The negatively charged lipid phosphatidylglycerol (PG) constitutes up to 10% of total lipids in photosynthetic membranes, and its deprivation in cyanobacteria is accompanied by chlorophyll (Chl) depletion. Indeed, radioactive labeling of the PG-depleted ΔpgsA mutant of Synechocystis sp. strain PCC 6803, which is not able to synthesize PG, proved the inhibition of Chl biosynthesis caused by restriction on the formation of 5-aminolevulinic acid and protochlorophyllide. Although the mutant accumulated chlorophyllide, the last Chl precursor, we showed that it originated from dephytylation of existing Chl and not from the block in the Chl biosynthesis. The lack of de novo-produced Chl under PG depletion was accompanied by a significantly weakened biosynthesis of both monomeric and trimeric photosystem I (PSI) complexes, although the decrease in cellular content was manifested only for the trimeric form. However, our analysis of ΔpgsA mutant, which lacked trimeric PSI because of the absence of the PsaL subunit, suggested that the virtual stability of monomeric PSI is a result of disintegration of PSI trimers. Interestingly, the loss of trimeric PSI was accompanied by accumulation of monomeric PSI associated with the newly synthesized CP43 subunit of photosystem II. We conclude that the absence of PG results in the inhibition of Chl biosynthetic pathway, which impairs synthesis of PSI, despite the accumulation of chlorophyllide released from the degraded Chl proteins. Based on the knowledge about the role of PG in prokaryotes, we hypothesize that the synthesis of Chl and PSI complexes are colocated in a membrane microdomain requiring PG for integrity.
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Affiliation(s)
- Jana Kopečná
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Jan Pilný
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Vendula Krynická
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Aleš Tomčala
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Mihály Kis
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Zoltan Gombos
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Josef Komenda
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Roman Sobotka
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
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10
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Wirth R, Lakatos G, Böjti T, Maróti G, Bagi Z, Kis M, Kovács A, Ács N, Rákhely G, Kovács KL. Metagenome changes in the mesophilic biogas-producing community during fermentation of the green alga Scenedesmus obliquus. J Biotechnol 2015; 215:52-61. [PMID: 26087313 DOI: 10.1016/j.jbiotec.2015.06.396] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 06/08/2015] [Accepted: 06/12/2015] [Indexed: 01/02/2023]
Abstract
A microalgal biomass offers a potential alternative to the maize silage commonly used in biogas technology. In this study, photoautotrophically grown Scenedesmus obliquus was used as biogas substrate. This microalga has a low C/N ratio of 8.5 relative to the optimum 20-30. A significant increase in the ammonium ion content was not observed. The methane content of the biogas generated from Sc. obliquus proved to be higher than that from maize silage, but the specific biogas yield was lower. Semi-continuous steady biogas production lasted for 2 months. Because of the thick cell wall of Sc. obliquus, the biomass-degrading microorganisms require additional time to digest its biomass. The methane concentration in the biogas was also high, in co-digestion (i.e., 52-56%) as in alga-fed anaerobic digestion (i.e., 55-62%). These results may be related to the relative predominance of the order Clostridiales in co-digestion and to the more balanced C/N ratio of the mixed algal-maize biomass. Predominance of the order Methanosarcinales was observed in the domain Archaea, which supported the diversity of metabolic pathways in the process.
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Affiliation(s)
- Roland Wirth
- Department of Biotechnology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary.
| | - Gergely Lakatos
- Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary.
| | - Tamás Böjti
- Department of Biotechnology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary.
| | - Gergely Maróti
- Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary.
| | - Zoltán Bagi
- Department of Biotechnology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary.
| | - Mihály Kis
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary.
| | - Attila Kovács
- Phytoplankton and Macrophyte Research Team, Balaton Limnological Institute, Klebersberg Kuno 3, H-8237 Tihany, Hungary.
| | - Norbert Ács
- Department of Biotechnology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary.
| | - Gábor Rákhely
- Department of Biotechnology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; Institute of Biophysics, Biological Research Center, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary.
| | - Kornél L Kovács
- Department of Biotechnology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; Institute of Biophysics, Biological Research Center, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary; Department of Oral Biology and Experimental Dental Research, University of Szeged, Tisza L. krt. 64, H-6720 Szeged, Hungary.
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11
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Kłodawska K, Kovács L, Várkonyi Z, Kis M, Sozer Ö, Laczkó-Dobos H, Kóbori O, Domonkos I, Strzałka K, Gombos Z, Malec P. Elevated Growth Temperature Can Enhance Photosystem I Trimer Formation and Affects Xanthophyll Biosynthesis in Cyanobacterium Synechocystis sp. PCC6803 Cells. ACTA ACUST UNITED AC 2014; 56:558-71. [DOI: 10.1093/pcp/pcu199] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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12
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Kis M, Asztalos E, Sipka G, Maróti P. Assembly of photosynthetic apparatus in Rhodobacter sphaeroides as revealed by functional assessments at different growth phases and in synchronized and greening cells. Photosynth Res 2014; 122:261-273. [PMID: 25022916 DOI: 10.1007/s11120-014-0026-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Accepted: 06/30/2014] [Indexed: 06/03/2023]
Abstract
The development of photosynthetic membranes of intact cells of Rhodobacter sphaeroides was tracked by light-induced absorption spectroscopy and induction and relaxation of the bacteriochlorophyll fluorescence. Changes in membrane structure were induced by three methods: synchronization of cell growth, adjustment of different growth phases and transfer from aerobic to anaerobic conditions (greening) of the bacteria. While the production of the bacteriochlorophyll and carotenoid pigments and the activation of light harvesting and reaction center complexes showed cell-cycle independent and continuous increase with characteristic lag phases, the accumulation of phospholipids and membrane potential (electrochromism) exhibited stepwise increase controlled by cell division. Cells in the stationary phase of growth demonstrated closer packing and tighter energetic coupling of the photosynthetic units (PSU) than in their early logarithmic stage. The greening resulted in rapid (within 0-4 h) induction of BChl synthesis accompanied with a dominating role for the peripheral light harvesting system (up to LH2/LH1 ~2.5), significantly increased rate (~7·10(4) s(-1)) and yield (F v/F max ~0.7) of photochemistry and modest (~2.5-fold) decrease of the rate of electron transfer (~1.5·10(4) s(-1)). The results are discussed in frame of a model of sequential assembly of the PSU with emphasis on crowding the LH2 complexes resulting in an increase of the connectivity and yield of light capture on the one hand and increase of hindrance to diffusion of mobile redox agents on the other hand.
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Affiliation(s)
- M Kis
- Department of Medical Physics, University of Szeged, Rerrich Béla tér 1, Szeged, 6720, Hungary
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13
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Talamantes T, Ughy B, Domonkos I, Kis M, Gombos Z, Prokai L. Label-free LC-MS/MS identification of phosphatidylglycerol-regulated proteins in Synechocystis
sp. PCC6803. Proteomics 2014; 14:1053-7. [DOI: 10.1002/pmic.201300372] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 01/04/2014] [Accepted: 02/20/2014] [Indexed: 01/21/2023]
Affiliation(s)
- Tatjana Talamantes
- Department of Molecular Biology and Immunology; University of North Texas Health Science Center; Fort Worth TX USA
| | - Bettina Ughy
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Plant Biology; Szeged Hungary
| | - Ildikó Domonkos
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Plant Biology; Szeged Hungary
| | - Mihály Kis
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Plant Biology; Szeged Hungary
| | - Zoltán Gombos
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Plant Biology; Szeged Hungary
| | - Laszlo Prokai
- Department of Molecular Biology and Immunology; University of North Texas Health Science Center; Fort Worth TX USA
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14
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Domonkos I, Kis M, Gombos Z, Ughy B. Carotenoids, versatile components of oxygenic photosynthesis. Prog Lipid Res 2013; 52:539-61. [PMID: 23896007 DOI: 10.1016/j.plipres.2013.07.001] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 07/19/2013] [Accepted: 07/19/2013] [Indexed: 12/13/2022]
Abstract
Carotenoids (CARs) are a group of pigments that perform several important physiological functions in all kingdoms of living organisms. CARs serve as protective agents, which are essential structural components of photosynthetic complexes and membranes, and they play an important role in the light harvesting mechanism of photosynthesizing plants and cyanobacteria. The protection against reactive oxygen species, realized by quenching of singlet oxygen and the excited states of photosensitizing molecules, as well as by the scavenging of free radicals, is one of the main biological functions of CARs. X-ray crystallographic localization of CARs revealed that they are present at functionally and structurally important sites of both the PSI and PSII reaction centers. Characterization of a CAR-less cyanobacterial mutant revealed that while the absence of CARs prevents the formation of PSII complexes, it does not abolish the assembly and function of PSI. CAR molecules assist in the formation of protein subunits of the photosynthetic complexes by gluing together their protein components. In addition to their aforementioned indispensable functions, CARs have a substantial role in the formation and maintenance of proper cellular architecture, and potentially also in the protection of the translational machinery under stress conditions.
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Affiliation(s)
- Ildikó Domonkos
- Institute of Plant Biology, Biological Research Centre of Hungarian Academy of Sciences, P.O. Box 521, H-6701 Szeged, Hungary
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15
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Dobrikova AG, Domonkos I, Sözer Ö, Laczkó-Dobos H, Kis M, Párducz Á, Gombos Z, Apostolova EL. Effect of partial or complete elimination of light-harvesting complexes on the surface electric properties and the functions of cyanobacterial photosynthetic membranes. Physiol Plant 2013; 147:248-260. [PMID: 22582961 DOI: 10.1111/j.1399-3054.2012.01648.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Influence of the modification of the cyanobacterial light-harvesting complex [i.e. phycobilisomes (PBS)] on the surface electric properties and the functions of photosynthetic membranes was investigated. We used four PBS mutant strains of Synechocystis sp. PCC6803 as follows: PAL (PBS-less), CK (phycocyanin-less), BE (PSII-PBS-less) and PSI-less/apcE(-) (PSI-less with detached PBS). Modifications of the PBS content lead to changes in the cell morphology and surface electric properties of the thylakoid membranes as well as in their functions, such as photosynthetic oxygen-evolving activity, P700 kinetics and energy transfer between the pigment-protein complexes. Data reveal that the complete elimination of PBS in the PAL mutant causes a slight decrease in the electric dipole moments of the thylakoid membranes, whereas significant perturbations of the surface charges were registered in the membranes without assembled PBS-PSII macrocomplex (BE mutant) or PSI complex (PSI-less mutant). These observations correlate with the detected alterations in the membrane structural organization. Using a polarographic oxygen rate electrode, we showed that the ratio of the fast to the slow oxygen-evolving PSII centers depends on the partial or complete elimination of light-harvesting complexes, as the slow operating PSII centers dominate in the PBS-less mutant and in the mutant with detached PBS.
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Affiliation(s)
- Anelia G Dobrikova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
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16
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Tóth T, Zsiros O, Kis M, Garab G, Kovács L. Cadmium exerts its toxic effects on photosynthesis via a cascade mechanism in the cyanobacterium, Synechocystis PCC 6803. Plant Cell Environ 2012; 35:2075-86. [PMID: 22583050 DOI: 10.1111/j.1365-3040.2012.02537.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Despite intense research, the mechanism of Cd(2+) toxicity on photosynthesis is still elusive because of the multiplicity of the inhibitory effects and different barriers in plants. The quick Cd(2+) uptake in Synechocystis PCC 6803 permits the direct interaction of cadmium with the photosynthetic machinery and allows the distinction between primary and secondary effects. We show that the CO(2) -dependent electron transport is rapidly inhibited upon exposing the cells to 40 µm Cd(2+) (50% inhibition in ∼15 min). However, during this time we observe only symptoms of photosystem I acceptor side limitation and a build of an excitation pressure on the reaction centres, as indicated by light-induced P700 redox transients, O(2) polarography and changes in chlorophyll a fluorescence parameters. Inhibitory effects on photosystem II electron transport and the degradation of the reaction centre protein D1 can only be observed after several hours, and only in the light, as revealed by chlorophyll a fluorescence transients, thermoluminescence and immunoblotting. Despite the marked differences in the manifestations of these short- and long-term effects, they exhibit virtually the same Cd(2+) concentration dependence. These data strongly suggest a cascade mechanism of the toxic effect, with a primary effect in the dark reactions.
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Affiliation(s)
- Tünde Tóth
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, PO Box 521, H-6726 Szeged, Hungary
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17
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Kłodawska K, Malec P, Kis M, Gombos Z, Strzałka K. EPR study of thylakoid membrane dynamics in mutants of the carotenoid biosynthesis pathway of Synechocystis sp. PCC6803. Acta Biochim Pol 2012; 59:87-90. [PMID: 22428145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 03/01/2012] [Indexed: 05/31/2023]
Abstract
EPR spectroscopy using 5-doxylstearic acid (5-SASL) and 16-doxylstearic acid (16-SASL) spin probes was used to study the fluidity of thylakoid membranes. These were isolated from wild type Synechocystis and from several mutants in genes encoding selected enzymes of the carotenoid biosynthesis pathway and/or acyl-lipid desaturases. Cyanobacteria were cultivated at 25°C and 35°C under different light regimes: photoautotrophically (PAG) and/or in light-activated heterotrophic conditions (LAHG). The relative fluidity of membranes was estimated from EPR spectra based on the empirical outermost splitting parameter in a temperature range from 15°C to 40°C. Our findings demonstrate that in native thylakoid membranes the elimination of xanthophylls decreased fluidity in the inner membrane region under optimal growth conditions (25°C) and increased it under sublethal heat stress (35°C). This indicated that the overall fluidity of native photosynthetic membranes in cyanobacteria may be influenced by the ratio of polar to non-polar carotenoid pools under different environmental conditions.
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Affiliation(s)
- Kinga Kłodawska
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków
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18
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Kłodawska K, Malec P, Kis M, Gombos Z, Strzałka K. EPR study of thylakoid membrane dynamics in mutants of the carotenoid biosynthesis pathway of Synechocystis sp. PCC6803. Acta Biochim Pol 2012. [DOI: 10.18388/abp.2012_2178] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
EPR spectroscopy using 5-doxylstearic acid (5-SASL) and 16-doxylstearic acid (16-SASL) spin probes was used to study the fluidity of thylakoid membranes. These were isolated from wild type Synechocystis and from several mutants in genes encoding selected enzymes of the carotenoid biosynthesis pathway and/or acyl-lipid desaturases. Cyanobacteria were cultivated at 25°C and 35°C under different light regimes: photoautotrophically (PAG) and/or in light-activated heterotrophic conditions (LAHG). The relative fluidity of membranes was estimated from EPR spectra based on the empirical outermost splitting parameter in a temperature range from 15°C to 40°C. Our findings demonstrate that in native thylakoid membranes the elimination of xanthophylls decreased fluidity in the inner membrane region under optimal growth conditions (25°C) and increased it under sublethal heat stress (35°C). This indicated that the overall fluidity of native photosynthetic membranes in cyanobacteria may be influenced by the ratio of polar to non-polar carotenoid pools under different environmental conditions.
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19
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Itoh S, Kozuki T, Nishida K, Fukushima Y, Yamakawa H, Domonkos I, Laczkó-Dobos H, Kis M, Ughy B, Gombos Z. Two functional sites of phosphatidylglycerol for regulation of reaction of plastoquinone QB in photosystem II. Biochimica et Biophysica Acta (BBA) - Bioenergetics 2012; 1817:287-97. [DOI: 10.1016/j.bbabio.2011.10.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 10/07/2011] [Accepted: 10/11/2011] [Indexed: 10/16/2022]
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20
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Laczkó-Dobos H, Todinova SJ, Sözer Ö, Komenda J, Kis M, Sallai A, Dobrikova AG, Ughy B, Debreczeny M, Gombos Z, Apostolova EL, Domonkos I. Identification of thylakoid membrane thermal transitions in Synechocystis sp. PCC6803 photosynthetic mutants. Photosynth Res 2011; 107:237-246. [PMID: 21298342 DOI: 10.1007/s11120-011-9627-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 01/17/2011] [Indexed: 05/30/2023]
Abstract
We used differential scanning calorimetry (DSC) as a technique capable of identifying photosynthetic complexes on the basis of their calorimetric transitions. Annotation of thermal transitions was carried out with thylakoid membranes isolated from various photosynthetic mutants of Synechocystis sp. PCC6803. The thylakoid membranes exhibited seven major DSC bands between 40 and 85°C. The heat sorption curves were analyzed both by mathematical deconvolution of the overall endotherms and by a subsequent annealing procedure. The successive annealing procedure proved to be more reliable technique than mathematical deconvolution in assigning thermal transitions. The main DSC band, around 47°C, resulting from the high enthalpy change that corresponds to non-interacting complex of PSII, was assigned using the PSI-less/apcE(-) mutant cells. Another band around 68-70°C relates to the denaturation of PSII surrounded by other proteins of the photosynthetic complexes in wild type and PSI-less/apcE(-) cells. A further major transition found at 82-84°C corresponds to the PSI core complex of wild type and PSII-deficient BE cells. Other transition bands between 50-67 and 65-75°C are believed to relate to ATP synthase and cytochrome b(6)f, respectively. These thermal transitions were obtained with thylakoids isolated from PSI(-)/PSII(-) mutant cells. Some minor bands determined at 59 and 83-84°C correspond to an unknown complex and NADH dehydrogenase, respectively. These annotations were done by PSI-less/apcE(-) and PSI(-)/PSII(-) mutants.
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Affiliation(s)
- Hajnalka Laczkó-Dobos
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
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21
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Sozer O, Komenda J, Ughy B, Domonkos I, Laczkó-Dobos H, Malec P, Gombos Z, Kis M. Involvement of carotenoids in the synthesis and assembly of protein subunits of photosynthetic reaction centers of Synechocystis sp. PCC 6803. Plant Cell Physiol 2010; 51:823-35. [PMID: 20231245 DOI: 10.1093/pcp/pcq031] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The crtB gene of Synechocystis sp. PCC 6803, encoding phytoene synthase, was inactivated in the Delta crtH mutant to generate a carotenoidless Delta crtH/B double mutant. Delta crtH mutant cells were used because they had better transformability than wild-type cells, most probably due to their adaptation to partial carotenoid deficiency. Cells of the Delta crtH/B mutant were light sensitive and could grow only under light-activated heterotrophic growth conditions in the presence of glucose. Carotenoid deficiency did not significantly affect the cellular content of phycobiliproteins while the chlorophyll content of the mutant cells decreased. The mutant cells exhibited no oxygen-evolving activity, suggesting the absence of photochemically active PSII complexes. This was confirmed by 2D electrophoresis of photosynthetic membrane complexes. Analyses identified only a small amount of a non-functional PSII core complex lacking CP43, while the monomeric and dimeric PSII core complexes were absent. On the other hand, carotenoid deficiency did not prevent formation of the cytochrome b(6)f complex and PSI, which predominantly accumulated in the monomeric form. Radioactive labeling revealed very limited synthesis of inner PSII antennae, CP47 and especially CP43. Thus, carotenoids are indispensable constituents of the photosynthetic apparatus, being essential not only for antioxidative protection but also for the efficient synthesis and accumulation of photosynthetic proteins and especially that of PSII antenna subunits.
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Affiliation(s)
- Ozge Sozer
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary
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22
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Benabderrahmane ML, Herrmann N, Wiśniewski K, Kecskemeti J, Andronic A, Barret V, Basrak Z, Bastid N, Buehler P, Cargnelli M, Caplar R, Cordier E, Deppner I, Crochet P, Dupieux P, Dzelalija M, Fabbietti L, Fodor Z, Gasik P, Gasparić I, Grishkin Y, Hartmann ON, Hildenbrand KD, Hong B, Kang TI, Kienle P, Kirejczyk M, Kim YJ, Kis M, Koczoń P, Korolija M, Kotte R, Lebedev A, Leifels Y, Lopez X, Manko V, Marton J, Mangiarotti A, Merschmeyer M, Matulewicz T, Petrovici M, Piasecki K, Rami F, Reischl A, Reisdorf W, Rogowska M, Ryu MS, Schmidt P, Schüttauf A, Seres Z, Sikora B, Sim KS, Simion V, Siwek-Wilczyńska K, Smolyankin V, Suzuki K, Tymiński Z, Widmann E, Xiao ZG, Yamazaki T, Yushmanov I, Zhang XY, Zhilin A, Zmeskal J, Bratkovskaya E, Cassing W. Measurement of the in-medium K0 inclusive cross section in pi(-) -induced reactions at 1.15 GeV/c. Phys Rev Lett 2009; 102:182501. [PMID: 19518864 DOI: 10.1103/physrevlett.102.182501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 03/20/2009] [Indexed: 05/27/2023]
Abstract
The K0 meson production by pi(-) mesons of 1.15 GeV/c momentum on C, Al, Cu, Sn, and Pb nuclear targets was measured with the FOPI spectrometer at the Schwer-Ionen-Synchrotron accelerator of GSI. Inclusive production cross sections and the momentum distributions of K0 mesons are compared to scaled elementary production cross sections and to predictions of theoretical models describing the in-medium production of kaons. The data represent a new reference for those models, which are widely used for interpretation of the strangeness production in heavy-ion collisions. The presented results demonstrate the sensitivity of the kaon production to the reaction amplitudes inside nuclei and point to the existence of a repulsive KN potential of 20+/-5 MeV at normal nuclear matter density.
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Abstract
PURPOSE Current helmet testing standards do not address the rotational components of an impact to the head. We describe a new testing paradigm used to measure the rotational acceleration of a headform and a protective helmet following an impact to the head in the horizontal plane. This impact simulation allows for the testing of currently available head protection devices in conditions thought to be important for the generation of cerebral concussion. The degree to which a particular helmet dampens rotational acceleration, and thus protects against concussion, can be assessed. METHODS Our testing device consists of a pneumatic piston that provides a measured impact to a standard headform. Four different helmets were tested using the described paradigm. RESULTS Acceleration curves for each helmet and the corresponding headform are presented. CONCLUSIONS Clear differences in rotational acceleration were demonstrated. Possible avenues of further investigation are discussed.
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Affiliation(s)
- M Kis
- Department of Neurosurgery, Dalhousie University, Halifax, NS, Canada
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24
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Domonkos I, Malec P, Sallai A, Kovács L, Itoh K, Shen G, Ughy B, Bogos B, Sakurai I, Kis M, Strzalka K, Wada H, Itoh S, Farkas T, Gombos Z. Phosphatidylglycerol is essential for oligomerization of photosystem I reaction center. Plant Physiol 2004; 134:1471-8. [PMID: 15064373 PMCID: PMC419823 DOI: 10.1104/pp.103.037754] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Our earlier studies with the pgsA mutant of Synechocystis PCC6803 demonstrated the important role of phosphatidylglycerol (PG) in PSII dimer formation and in electron transport between the primary and secondary electron-accepting plastoquinones of PSII. Using a long-term depletion of PG from pgsA mutant cells, we could induce a decrease not only in PSII but also in PSI activity. Simultaneously with the decrease in PSI activity, dramatic structural changes of the PSI complex were detected. A 21-d PG depletion resulted in the degradation of PSI trimers and concomitant accumulation of monomer PSI. The analyses of PSI particles isolated by MonoQ chromatography showed that, following the 21-d depletion, PSI trimers were no longer detectable in the thylakoid membranes. Immunoblot analyses revealed that the PSI monomers accumulating in the PG-depleted mutant cells do not contain PsaL, the protein subunit thought to be responsible for the trimer formation. Nevertheless, the trimeric structure of PSI reaction center could be restored by readdition of PG, even in the presence of the protein synthesis inhibitor lincomycin, indicating that free PsaL was present in thylakoid membranes following the 21-d PG depletion. Our data suggest an indispensable role for PG in the PsaL-mediated assembly of the PSI reaction center.
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Affiliation(s)
- Ildikó Domonkos
- Institute of Plant Biology, Biological Research Center of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary.
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Ermisch K, van den Berg AM, Bieber R, Glöckle W, Golak J, Hagemann M, Hannen VM, Harakeh MN, de Huu MA, Kalantar-Nayestanaki N, Kamada H, Kis M, Kuroś-Zołnierczuk J, Mahjour-Shafiei M, Micherdzińska A, Nogga A, Skibiński R, Witała H, Wörtche HJ. Search for three-nucleon force effects in analyzing powers for p-->d elastic scattering. Phys Rev Lett 2001; 86:5862-5865. [PMID: 11415380 DOI: 10.1103/physrevlett.86.5862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2001] [Indexed: 05/23/2023]
Abstract
A series of measurements have been performed at KVI to obtain the vector analyzing power A(y) of the (2)H(p-->,pd) reaction as a function of incident beam energy at energies of 120, 135, 150, and 170 MeV. For all these measurements, a range of theta(c.m.) from 30 degrees to 170 degrees has been covered. The purpose of these investigations is to observe possible spin-dependent effects beyond two-nucleon forces. When compared to the predictions of Faddeev calculations, based on two-nucleon forces only, significant deviations are observed at all energies and at center-of-mass angles between 70 degrees and 130 degrees. The addition of present-day three-nucleon forces does not improve the description of the data, demonstrating the still insufficient understanding of the properties of three-nucleon systems.
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Affiliation(s)
- K Ermisch
- Kernfysisch Versneller Instituut, NL-9747 AAGroningen, The Netherlands
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26
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Antal M, Mougin A, Kis M, Boros E, Steger G, Jakab G, Solymosy F, Branlant C. Molecular characterization at the RNA and gene levels of U3 snoRNA from a unicellular green alga, Chlamydomonas reinhardtii. Nucleic Acids Res 2000; 28:2959-68. [PMID: 10908360 PMCID: PMC102673 DOI: 10.1093/nar/28.15.2959] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A U3 snoRNA gene isolated from a Chlamydomonas reinhardtii (CRE:) genomic library contains putative pol III-specific transcription signals similar to those of RNA polymerase III-specific small nuclear (sn)RNA genes of higher plants. The 222 nt long CRE: U3 snoRNA was immunoprecipitated by anti-gamma-mpppN antisera, but not by anti-m(2,2,7)G antibodies, supporting the notion that it is a RNA polymerase III transcript. Tagged CRE: U3 snoRNA gene constructs were expressed in CRE: cells. Results of chemical and enzymatic structure probing of CRE: U3 snoRNA in solution and of DMS modification of CRE: U3 snoRNA under in vivo conditions revealed that the two-hairpin structure of the 5'-domain that is found in solution is no longer detected under in vivo conditions. The observed differences can be explained by the formation of several base pair interactions with the 18S and 5'-ETS parts of the pre-rRNA. A model that involves five intermolecular helices is proposed.
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Affiliation(s)
- M Antal
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, H-6701 Szeged, PO Box 521, Hungary
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27
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Benli IT, Akalin S, Duman E, Citak M, Kis M. The results of intraoperative autotransfusion in orthopaedic surgery. Bull Hosp Jt Dis 2000; 58:184-7. [PMID: 10711365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Perioperative hemorrhage associated with major orthopaedic surgery can become life threatening. Homologous bank blood transfusion can replace the volume of blood lost but it has serious disadvantages such as the transmission of viral agents, it has an insufficient platelet count, and transfusion reactions are possible. Hypotensive anesthesia, predeposited autologous blood transfusion and intraoperative autotransfusion are used to reduce these disadvantages. This study evaluates the results of 700 patients who underwent major orthopaedic intervention in our clinic between June 1991 and April 1998. Ninety-nine patients had hip surgery while 601 patients had spinal surgery. The autotransfusion unit saved an average of 858.9 +/- 136.8 cc of blood and an average of 1.9 +/- 1.2 units of saved blood was transfused. None of these patients needed homologous blood transfusion. One hundred patients who had spinal surgery during the same period were used as a control group. The control group required an average of 3.2 +/- 2.1 units of bank blood. Preoperative and postoperative hematocrit values revealed a statistically significant difference between the autotransfusion group and the homologous transfusion group (p < 0.05). The results of this study suggest that intraoperative autotransfusion prevents the decrease in hematocrit values while reducing the need for bank blood transfusion and hence avoiding the risk of transmission of viral infections.
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Affiliation(s)
- I T Benli
- 1st Department of Orthopaedics and Traumatology, Ankara Social Security Hospital, Turkey
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28
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Kovács L, Wiessner W, Kis M, Nagy F, Mende D, Demeter S. Short- and long-term redox regulation of photosynthetic light energy distribution and photosystem stoichiometry by acetate metabolism in the green alga, Chlamydobotrys stellata. Photosynth Res 2000; 65:231-47. [PMID: 16228490 DOI: 10.1023/a:1010650532693] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The effect of acetate metabolism on the light energy distribution between the two photosystems, on the PS II/PS I stoichiometry and on the expression of psbA and psbB and psaA genes was investigated in the green alga, Chlamydobotrys stellata during autotrophic (CO(2)), mixotrophic (CO(2) plus acetate) and photoheterotrophic (only acetate) cultivation. It was observed that acetate assimilation in the glyoxylate cycle resulted in a large drop in the ATP content and a concomitant increase in the NADPH content of the cells. The combined effect of high NADPH concentration and linear electron transport brought about an over-reduction of the inter-photosystem electron transport components. The reduced state of the inter-photosystem components initiated a state 1/state 2 transition of LHC II and a decrease in the PS II/PS I ratio. The PS II/ PS I ratio was reduced because the synthesis of PS II reaction centers was repressed and that of the PS I reaction centers was slightly enhanced by acetate cultivation. The amount of PsbA and PsbB proteins of PS II and the abundance of psbA mRNA decreased. The abundance of PS I PsaA protein and psaAmRNA were only slightly increased. All of the acetate-induced effects were reversible when the cells were transferred back to an acetate-free medium. Our observations demonstrate that the expression of the PS II psbA and psbB and PS I psaA genes is regulated by the redox state of the inter-photosystem components at the transcriptional level. Experiments carried out in the presence of DBMIB which facilitates the reduction of plastoquinone pool indicate that the expression of genes encoding the components of PS II and PS I are controlled by the redox state of a component (cytochrome b/f complex) located behind the plastoquinone pool.
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Affiliation(s)
- L Kovács
- Biological Research Center, Hungarian Academy of Sciences, P.O.Box 521, H-6701, Szeged, Hungary
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Aydin E, Solak AS, Tuzuner MM, Benli IT, Kis M. Z-plate instrumentation in thoracolumbar spinal fractures. Bull Hosp Jt Dis 1999; 58:92-7. [PMID: 10509201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Anterior decompression enables direct access and good canal clearance of the injury level in thoracolumbar spinal fractures, and decompressing the neural elements is shown to be an important factor for neurologic improvement and pain relief in many cases. In this study, results with anterior decompression and Z-plate instrumentation in thoracolumbar spinal fractures are reviewed. Nineteen patients with old spinal fracture (average: 3 years) and neural compression, and 15 patients with fresh thoracolumbar fractures with neurologic deficit and/or major anterior spinal canal obstruction had anterior decompression and Z-plate instrumentation with anterior fusion. Stabilization was protected with thoracolumbar thermoplastic braces for six months. Preoperative kyphotic deformity averaged 20.9 degrees (range: 7 degrees to 64 degrees), while it was an average of 8.0 degrees (range: -12 degrees to 35 degrees) postoperatively. Medullary canal compromise was 41% an average (range: 13% to 67%) and postoperatively it had an average value of 6% (range: 0% to 18%). Patients were followed up an average of 30 months (range: 25 to 36 months). The unchanged positions of bone grafts and statistically insignificant loss of correction in the sagittal plane are accepted as evidence for bony fusion in all patients. Z-plate instrumentation provides stable fixation. Additionally, the technique can be performed easily and has the added benefit of being MRI-compatible.
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Affiliation(s)
- E Aydin
- Department of Orthopaedics and Traumatology, SSK Ankara Hospital, Turkey
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Abstract
In cyanobacterial cells, fatty acid desaturation is one of the crucial steps in the acclimation processes to low-temperature conditions. The expression of all the four acyl lipid desaturase genes of Synechocystis PCC 6803 was studied as a function of temperature and separately as a function of light. We used cells grown at 25 degreesC in light-activated heterotrophic growth conditions. In these cells, the production of alpha-linolenic acid and 18:4 fatty acids was negligible and the synthesis of gamma-linolenic acid was remarkably suppressed compared with those of the cells grown photoautotrophically. The cells grown in the light in the presence of glucose showed no difference in fatty acid composition compared with cells grown photoautotrophically. The level of desC mRNA for delta9 desaturase was not affected by either the temperature or the light. It was constitutively expressed at 25 degreesC with and without illumination. The level of desB transcripts was negligible in the dark-grown cells and was enhanced about 10-fold by exposure of the cells to light. The maximum level of expression occurred within 15 min. The level of desA and desD mRNAs was higher in dark-grown cells than that of desB mRNA for omega3 desaturase. However, the induction of both desA and desD mRNAs for delta12 and delta6 desaturases, respectively, was enhanced by light about 10-fold. Rifampicin, chloramphenicol, and 3-(3, 4-dichlorophenyl)-1,1-dimethylurea completely blocked the induction of the expression of desA, desB, and desD. Consequently, we suggest the regulatory role of light via photosynthetic processes in the induction of the expression of acyl lipid desaturases.
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Affiliation(s)
- M Kis
- Institute of Plant Biology, Biological Research Center of the Hungarian Academy of Sciences, P.O. Box 521, H-6701 Szeged, Hungary
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Jakab G, Mougin A, Kis M, Pollák T, Antal M, Branlant C, Solymosy F. Chlamydomonas U2, U4 and U6 snRNAs. An evolutionary conserved putative third interaction between U4 and U6 snRNAs which has a counterpart in the U4atac-U6atac snRNA duplex. Biochimie 1997; 79:387-95. [PMID: 9352088 DOI: 10.1016/s0300-9084(97)86148-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The spliceosomal UsnRNAs U2, U4 and U6 from the green alga Chlamydomonas reinhardtii (Cre) were sequenced using a combination of RNA and cDNA sequencing methods and were compared to other sequenced UsnRNAs. The lengths of Cre U6 and Cre U2 RNAs are similar to those of their higher plant equivalents. Cre U4 RNA is shorter (139 nt) than its counterpart from higher plants (150-154 nt), and contains stem IV and loop D which are absent, with the exception of the Tetrahymena U4 RNA, from the U4 RNAs of other unicellular organisms studied to date. Base-pairing interactions between U6 and U4 RNAs and between U6 and U2 RNAs, identical to those described for mammalian and yeast systems, are structurally feasible in the Cre system. In addition, based on comparative analyses of the predicted U4/U6 RNA duplex from various species, an evolutionary conserved third putative U6-U4 interaction was found. Interestingly, it can also be formed with the recently discovered U6atac and U4atac RNAs. This is a strong support in favor of the possible biological significance of this third putative interaction. Based on comparative analysis, an extension of the earlier described U6-U2 interaction patterns is also proposed.
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Affiliation(s)
- G Jakab
- Institute of Plant Biology, Hungarian Academy of Sciences, Szeged
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Affiliation(s)
- A Pellegrineschi
- Department of Biology, St. Patrick's College, Co. Kildare, Ireland
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Jakab G, Kis M, Pollák T, Solymosy F. Nucleotide sequence of cytoplasmic 5S rRNA from a eukaryotic thermophilic unicellular alga, Cyanidium caldarium. Nucleic Acids Res 1993; 21:2770. [PMID: 8332476 PMCID: PMC309621 DOI: 10.1093/nar/21.11.2770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Affiliation(s)
- G Jakab
- Institute of Plant Physiology, Hungarian Academy of Sciences, Szeged
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Affiliation(s)
- M Kis
- Institute of Plant Physiology, Hungarian Academy of Sciences, Szeged
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Abstract
A case of cervical chondrosarcoma that recurred after incomplete excision is presented. The mass was removed in three stages and the involved vertebrae were fused. Excision of the huge mass with only minor complications was only possible by staging the procedure. Due to the location of the lesion, only marginal excision could be performed and the patient was given adjuvant radiotherapy. No signs of recurrence have been detected at 1-year follow-up and surgical measures to improve the function of the neurologically involved extremity are being undertaken.
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Affiliation(s)
- A M Alpaslan
- Department of Orthopaedics and Traumatology, Hacettepe University School of Medicine, Ankara, Turkey
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36
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Affiliation(s)
- G Jakab
- Institute of Plant Physiology, Hungarian Academy of Sciences, Szeged
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Affiliation(s)
- G Jakab
- Institute of Plant Physiology, Hungarian Academy of Sciences, Szeged
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Abstract
The clinical features, perioperative course, and postoperative outcomes of 144 patients who underwent microsurgical resection of craniopharyngioma were reviewed. Overall, 90% of the tumors were completely resected and 7% recurred. Evaluation of those patients who underwent primary resection revealed much better results. The operative techniques and approaches are reviewed in detail. The results of this series suggest that primary total removal of craniopharyngiomas yields the best long-term outcome for the patient. Experience has shown that the larger the tumor the greater will be the damage, both preoperatively and intraoperatively, to vital intracranial structures. Consequently, early diagnosis, at a stage when the tumor is still small, improves the chances of accomplishing complete removal and of achieving good operative results. The early diagnosis of craniopharyngioma, before it can produce devastating neurological defects, continues to be the principal goal of our medical and pediatric colleagues.
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Affiliation(s)
- M G Yaşargil
- Department of Neurosurgery, University Hospital of Zurich, Switzerland
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Affiliation(s)
- T Kiss
- Biological Research Center, Hungarian Academy of Sciences, Szeged
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40
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Affiliation(s)
- T Kiss
- Institute of Plant Physiology, Hungarian Academy of Sciences, Szeged
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Kiss T, Jakab G, Antal M, Pálfi Z, Hegyi H, Kis M, Solymosy F. Plant small nuclear RNAs. V. U4 RNA is present in broad bean plants in the form of sequence variants and is base-paired with U6 RNA. Nucleic Acids Res 1988; 16:5407-26. [PMID: 3387237 PMCID: PMC336775 DOI: 10.1093/nar/16.12.5407] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
U4 RNA, which is known to play an indispensable role in pre-mRNA splicing, is present in plant nuclei, has a canonical m3 2,2,7 G cap at its 5' end and is associated with U6 RNA in snRNP particles. It occurs in broad bean in the form of a number of sequence variants. Two of these were sequenced: U4A RNA is 154 and U4B RNA is 152 nucleotides long. Sequence similarity of broad bean U4B RNA is 94 per cent to broad bean U4A RNA, 65 per cent to rat U4A RNA, 61 per cent to Drosophila U4A RNA and 50 per cent to snR14, the U4 RNA equivalent of the yeast Saccharomyces cerevisiae. Sequence conservation is much more pronounced in the 5' half of the molecule than in its 3' half. The secondary structure of both variants of broad bean U4 RNA perfectly fits with that of all other U4 RNAs sequenced so far. Nucleotide changes between broad bean U4A and U4B RNAs are restricted to molecular regions that affect the thermodynamic stability of these molecules. A model is proposed for the base pairing interaction of broad bean U4 RNA with broad bean U6 RNA. This is the first report on the structure of a plant U4 RNA.
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Affiliation(s)
- T Kiss
- Institute of Plant Physiology, Hungarian Academy of Sciences, Szeged
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Gombos Z, Kis M, Páli T, Vigh L. Nitrate starvation induces homeoviscous regulation of lipids in the cell envelope of the blue-green alga, Anacystis nidulans. Eur J Biochem 1987; 165:461-5. [PMID: 3109903 DOI: 10.1111/j.1432-1033.1987.tb11461.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Replacement of the normal culture liquid to a nitrate-free medium resulted in an immediate drop in the ratio of protein to lipid in isolated cell envelopes of Anacystis nidulans cells. The relative fluidity of the envelope membranes or liposomes, made from the extracted lipids of the envelope, was estimated by measuring the steady-state fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene. A thermotrophic phase transition of lipids within the cytoplasmic membrane of intact cells was also revealed by detecting the temperature-dependent absorption changes in the proportion of zeaxanthin at 390 nm. It became evident that a decrease in the proportion of protein to lipid within the cell envelope was accompanied neither by changes in the microviscosity level, nor by shifting of characteristic temperatures of the liquid-crystalline-to-gel transition of lipids. In parallel with nitrate starvation, however, the proportion of saturated fatty acids of the envelope lipids increased markedly. Accumulation of saturated, longer-chain (C18) fatty acids at the cost of C16 counterparts upon nitrate deprivation occurred in all of the complex lipids. In accordance with these findings, a pronounced decrease in the fluidity was demonstrated for the liposomes prepared from the envelope polar lipids of nitrate-starved cells compared with the corresponding control, throughout the temperature range (45-5 degrees C) studied. We propose that the fluidizing effect due to a fall in the ratio of protein to lipid was compensated by a rapidly triggering regulatory process which enables the preservation of the fluidity characteristics at an optimal level within the cell envelope of A. nidulans.
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Brazković N, Kis M, Antonić M. [Significance of mediastinal and diaphragmatic manifestations in the evaluation of the operability of bronchial carcinoma]. Nar Zdrav 1976; 32:374-5. [PMID: 1029804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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