Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)最新文献_第2页

Microwaves and cellular immunity 微波和细胞免疫

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-10-01 DOI: 10.1016/S0302-4598(99)00058-6

E.E Fesenko , V.R Makar , E.G Novoselova , V.B Sadovnikov

引用次数: 61

Effect of a 7-tesla homogeneous magnetic field on mammalian cells 7特斯拉均匀磁场对哺乳动物细胞的影响

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-10-01 DOI: 10.1016/S0302-4598(99)00066-5

Hideki Sakurai , Kazumasa Okuno , Atsushi Kubo , Kayoko Nakamura , Makoto Shoda

引用次数: 25

Effects of a pulsing electric signal on the cross membrane potential and the cell division potentiality of a single cell of tobacco 脉冲电信号对烟草单细胞跨膜电位和细胞分裂电位的影响

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-10-01 DOI: 10.1016/S0302-4598(99)00065-3

Hideaki Matsuoka, Hidekazu Sotoyama, Mikako Saito, Ki-Bong Oh, Shigetoshi Horikiri

{"title":"Effects of a pulsing electric signal on the cross membrane potential and the cell division potentiality of a single cell of tobacco","authors":"Hideaki Matsuoka, Hidekazu Sotoyama, Mikako Saito, Ki-Bong Oh, Shigetoshi Horikiri","doi":"10.1016/S0302-4598(99)00065-3","DOIUrl":"10.1016/S0302-4598(99)00065-3","url":null,"abstract":"<div>A pulsing electric signal (pulse width 10 s) was applied to a single cell of cultured tobacco, line BY-2, by inserting a multifunctional microelectrode (MME) into the cell. The electric voltage (VET) was loaded between the electrode terminals of the MME and the reference electrode situated in the extracellular medium. Since the electrical impedance of the MME was as large as that of the cell membrane, the effective potential acting across the cell membrane (VCMP) should be only some portion of VET. The MME enabled simultaneous measurement of VET and VCMP. When VET was varied from 0 to −1 V, VCMP changed linearly in proportion to VET. When VET variation range was enlarged (from 0 to −2 V), VCMP changing pattern became a declined curve. When VET variation range was further enlarged (from 0 to −5 V), the VCMP changing pattern showed a saturation curve. Under this condition, the cell division potentiality decreased accordingly. Based on these results, the feasibility of VCMP as an indicator of the effective intensity of an electric stress signal is discussed. In the present case of a BY-2 cell, a proper intensity of VCMP that could cause an appreciable stress and not a lethal signal was estimated as −250 mV.</div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"49 1","pages":"Pages 65-72"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(99)00065-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21475879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Tuning the redox potential of riboflavin by zirconium phosphate in carbon paste electrodes 磷酸锆在碳糊电极中调控核黄素的氧化还原电位

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-10-01 DOI: 10.1016/S0302-4598(99)00061-6

A. Malinauskas , T. Ruzgas , L. Gorton

引用次数: 30

Incorporation of transmembrane hydroxide transport into the chemiosmotic theory 将氢氧化物跨膜运输纳入化学渗透理论

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-10-01 DOI: 10.1016/S0302-4598(99)00064-1

Aubrey D.N.J de Grey

{"title":"Incorporation of transmembrane hydroxide transport into the chemiosmotic theory","authors":"Aubrey D.N.J de Grey","doi":"10.1016/S0302-4598(99)00064-1","DOIUrl":"10.1016/S0302-4598(99)00064-1","url":null,"abstract":"<div>A cornerstone of textbook bioenergetics is that oxidative ATP synthesis in mitochondria requires, in normal conditions of internal and external pH, a potential difference (Δψ) of well over 100 mV between the aqueous compartments that the energy-transducing membrane separates. Measurements of Δψ inferred from diffusion of membrane-permeant ions confirm this, but those using microelectrodes consistently find no such Δψ — a result ostensibly irreconcilable with the chemiosmotic theory. Transmembrane hydroxide transport necessarily accompanies mitochondrial ATP synthesis, due to the action of several carrier proteins; this nullifies some of the proton transport by the respiratory chain. Here, it is proposed that these carriers' structure causes the path of this “lost” proton flow to include a component perpendicular to the membrane but within the aqueous phases, so maintaining a steady-state proton-motive force between the water at each membrane surface and in the adjacent bulk medium. The conflicting measurements of Δψ are shown to be consistent with the response of this system to its chemical environment.</div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"49 1","pages":"Pages 43-50"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(99)00064-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21475876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Interactions of anthracyclines with zwitterionic phospholipid monolayers at the air–water interface 蒽环类药物与空气-水界面两性离子磷脂单层的相互作用

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-10-01 DOI: 10.1016/S0302-4598(99)00063-X

F. Bordi , C. Cametti , A. Motta , M. Diociaiuti , A. Molinari

{"title":"Interactions of anthracyclines with zwitterionic phospholipid monolayers at the air–water interface","authors":"F. Bordi , C. Cametti , A. Motta , M. Diociaiuti , A. Molinari","doi":"10.1016/S0302-4598(99)00063-X","DOIUrl":"10.1016/S0302-4598(99)00063-X","url":null,"abstract":"<div>The present note describes the use of surface pressure measurements (Langmuir monolayer technique) for the analysis of interactions of two different anthracyclines (adriamycin and daunorubicin) with a non-ionic, zwitterionic phospholipid monolayer, at the air–water interface. Because the surface membrane of the cell is the first barrier encountered by the anthracyclines in the treatment of cancer, drug–membrane interactions studied in model (monolayers or bilayers) and natural systems play an important role in the understanding of the bioactivity properties of these molecules. We report here the rate constants of the adsorption process of adriamycin and daunorubicin in the presence of a zwitterionic phospholipid monolayer at the air–water interface. Because interactions with the lipid monolayer strongly depend on the molecular packing of the lipid, we investigated this process at a relatively low surface pressure (7 mN/m), the interactions being favoured by the gaseous and liquid expanded structure of the lipid monolayer. The apparent molecular area of these molecules during the insertion into the lipid film and their interactions with the phospholipid polar head groups was evaluated and the estimated percentage of anthracyclines at the interface after adsorption into the lipid monolayer is briefly discussed. The rate constants for the adsorption and desorption process at the water–monolayer interface have been calculated on the basis of a single-exponential model. The observed difference of these parameters for daunorubicin and adriamycin suggests a different interaction of these anthracyclines during the adsorption to and/or penetration across the phospholipid monolayer.</div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"49 1","pages":"Pages 51-56"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(99)00063-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21475877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 17

Technical aspects of microwave thermotherapy 微波热疗的技术方面

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00039-2

Jan Vrba , Miroslav Lapeš , Ladislav Oppl

{"title":"Technical aspects of microwave thermotherapy","authors":"Jan Vrba , Miroslav Lapeš , Ladislav Oppl","doi":"10.1016/S0302-4598(99)00039-2","DOIUrl":"10.1016/S0302-4598(99)00039-2","url":null,"abstract":"<div>We describe our new technical results dealing with microwave thermotherapy (hyperthermia) in cancer treatment, see Refs. [S.B. Field, C. Franconi (Eds.), Physics and technology of hyperthermia, NATO Seminar Proceedings, Urbino, Italy, 1986; J. Hand, J.R. James (Eds.), Physical Techniques in Clinical Hyperthermia, Wiley, New York, 1986; J. Vrba, M. Lapeš, Microwave Applicators for Medical Purposes, CTU Press, 1996, in Czech; J. Vrba, C. Franconi, M. Lapeš, Theoretical limits for the penetration depth of the intracavitary applicators, International Journal of Hyperthermia, 12:6 (1996) 737–742; C. Franconi, J. Vrba, F. Montecchia, 27 MHz hybrid evanescent-mode applicators with flexible heating field for deep and safe subcutaneous hyperthermia, International Journal of Hyperthermia, 9:5 (1993) 655–6741.]. Our research interest is to develop applicators for deep local heating and for intracavitary cancer and/or prostate treatment as well. Further, a system for 3D SAR distribution measurements in water phantom is explained. Basic evaluation of clinical results is given.</div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 2","pages":"Pages 305-309"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(99)00039-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21247954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 31

Free energy of charge transfer and intraprotein electric field: method of calculation depends on the charge state of protein at a given structure 电荷转移自由能和蛋白内电场:计算方法取决于给定结构下蛋白质的电荷状态

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00021-5

Edward L. Mertz , Lev I. Krishtalik

{"title":"Free energy of charge transfer and intraprotein electric field: method of calculation depends on the charge state of protein at a given structure","authors":"Edward L. Mertz , Lev I. Krishtalik","doi":"10.1016/S0302-4598(99)00021-5","DOIUrl":"10.1016/S0302-4598(99)00021-5","url":null,"abstract":"<div>Free energy of charge transfer presents a basic characteristic of reactions such as protonation, oxido-reduction and similar. Evaluation of this quantity requires calculation of charging energy. Proteins are structured dielectrics, and a consistent incorporation of their structure into calculation of intraprotein electric field results in expression for charging energy of an active group in protein, which is essentially different from that for a simple dielectric. An algorithm for semi-continuum calculation of relevant free energies is described. First of the two components of charging energy in protein, energy of the medium response to charge redistribution in reactants, should be always calculated as the charging energy by the charge redistribution using the static dielectric constant of protein. The second term is interaction energy of the charge redistribution with the `frozen' electric field of the system before reaction. Charges of protein groups, at which the protein structure has been determined, are often different from those before reaction of charge transfer, so is the corresponding intraprotein field. The field is expressed through either both the optical and static dielectric constants of protein or only optical one depending on whether the charges of protein groups before reaction and upon structural analysis are the same or not. Proper allowance for difference in charges of reacting groups before reaction and upon structural analysis of protein is thermodynamically necessary and quantitatively important. The expression for activation free energy for charge transfer in proteins is derived in the form presenting explicitly an invariant contribution of protein structure.</div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 2","pages":"Pages 397-405"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(99)00021-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21247197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Membrane microextension: a possible mechanism for establishing molecular contact in electrofusion 膜微延伸:电熔中建立分子接触的可能机制

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00043-4

Subrata Biswas, Sujoy K Guha

{"title":"Membrane microextension: a possible mechanism for establishing molecular contact in electrofusion","authors":"Subrata Biswas, Sujoy K Guha","doi":"10.1016/S0302-4598(99)00043-4","DOIUrl":"10.1016/S0302-4598(99)00043-4","url":null,"abstract":"<div>True cell membrane contact is an essential condition for electro-pulsed cell fusion, but initial morphological perturbation leading to true contact is still not clear. Dielectrophoresis mediated compression and fusogenic pulse induced compaction of cells led to rapid merger of tight membranes, and deprived direct microscopic view of surface membrane perturbation. Freely suspending cells with large and different cell–cell gaps may proceed to electrofusion with perturbed membrane and initiates fusion events at different time. These pulsed exposed cells can be used for capturing changes in the membrane surface and early electrofusion events. Early stage of fusion of freely suspended intact human erythrocytes exposed to single exponential decay pulse was studied by scanning electron microscopy (SEM). Field pulse induces small membrane bumps. Interaction of bumps on adjacent membranes lead to true membrane contact and form bridges between the membranes as microextension, combining both membranes into a topologically single structure. Some fusion products showed expanded fusion zones, which suggest indication of open lumen at contact area.</div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 2","pages":"Pages 435-440"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(99)00043-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21247202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Quantum-mechanical coherence in cell microtubules: a realistic possibility? 细胞微管中的量子力学相干性:现实的可能性?

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00015-X

N.E. Mavromatos

{"title":"Quantum-mechanical coherence in cell microtubules: a realistic possibility?","authors":"N.E. Mavromatos","doi":"10.1016/S0302-4598(99)00015-X","DOIUrl":"10.1016/S0302-4598(99)00015-X","url":null,"abstract":"<div>We discuss the possibility of quantum-mechanical coherence in Cell MicroTubules (MT), based on recent developments in quantum physics. We focus on potential mechanisms for `energy-loss-free' transport along the microtubules, which could be considered as realizations of Fröhlich's ideas on the role of solitons for superconductivity and/or biological matter. In particular, by representing the MT arrangements as cavities, we review a novel scenario, suggested in collaboration with D.V. Nanopoulos, concerning the formation of macroscopic (or mesoscopic) quantum-coherent states, as a result of the (quantum-electromagnetic) interactions of the MT dimers with the surrounding molecules of the ordered water in the interior of the MT cylinders. We suggest specific experiments to test the above-conjectured quantum nature of the microtubular arrangements inside the cell. These experiments are similar in nature to those in atomic physics, used in the detection of the Rabi-Vacuum coupling between coherent cavity modes and atoms. Our conjecture is that a similar Rabi-Vacuum-splitting phenomenon occurs in the absorption (or emission) spectra of the MT dimers, which would constitute a manifestation of the dimer coupling with the coherent modes in the ordered-water environment (dipole quanta), which emerge due to the phenomenon of `super-radiance'.</div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 2","pages":"Pages 273-284"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(99)00015-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21247950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 17