Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)最新文献_第4页

Interactions between carbonic anhydrase and some decarboxylating enzymes as studied by a new bioelectrochemical approach 用一种新的生物电化学方法研究了碳酸酐酶与脱羧酶的相互作用

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00004-5

Francesco Botrè , Franco Mazzei

{"title":"Interactions between carbonic anhydrase and some decarboxylating enzymes as studied by a new bioelectrochemical approach","authors":"Francesco Botrè , Franco Mazzei","doi":"10.1016/S0302-4598(99)00004-5","DOIUrl":"10.1016/S0302-4598(99)00004-5","url":null,"abstract":"<div>This work presents the results of a study, carried out by recently developed amperometric bioelectrodes, on the interactions between carbonic anhydrase (CA) and the decarboxylating enzymes arginine decarboxylase (ADC), l-lysine decarboxylase (LDC), and l-ornithine decarboxylase (ODC). These are all pyridoxal-phosphate dependent enzymes and catalyze the decarboxylation reaction of the respective amino acids, to give carbon dioxide and the corresponding diamine (agmatine, cadaverine, and putrescine, respectively). The rate of each decarboxylase catalyzed reaction was measured by monitoring the production of the respective diamine by a plant tissue diamino oxidase (DAO) based bioelectrode. DAO is the enzyme which catalyzes the oxidation of agmatine, cadaverine, and putrescine with the production of NH3 and H2O2. DAO-based bioelectrodes consist of an amperometric H2O2 electrode, coupled to the biocatalytic membrane formed by a whole plant tissue (lentil cotyledon) containing the enzyme DAO, immobilized on a dialysis membrane by polyazetidine prepolymer (PAP). The bioelectrodes were calibrated and characterized in standard solutions of agmatine, cadaverine, and putrescine. Kinetic studies to measure decarboxylase activity were performed in the presence of different concentrations of ADC, LDC, and ODC, resulting in a lowest detection limit of 10, 25, and 10 U l−1, respectively. The effect of bovine CA II (bCAII) was evaluated in the presence of 500 U l−1 of each decarboxylase, showing a marked increase of the rate of the decarboxylation reaction. These results suggest that (i) CA can be used to enhance the performance of decarboxylase-based biosensors, and (ii) it possibly plays further physiological roles, acting synergistically, at specific cellular and subcellular sites, with low-activity decarboxylating enzymes.</div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 2","pages":"Pages 463-467"},"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)00004-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21247063","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

Problems of weak electromagnetic field effects in cell biology1 细胞生物学中的弱电磁场效应问题

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00012-4

Hermann Berg

{"title":"Problems of weak electromagnetic field effects in cell biology1","authors":"Hermann Berg","doi":"10.1016/S0302-4598(99)00012-4","DOIUrl":"10.1016/S0302-4598(99)00012-4","url":null,"abstract":"<div>Electrostimulations of cells by weak electric or electromagnetic LF and HF-fields are applied widely today; capacitively or inductively coupled, however, they are seldom applied for cell-free and membrane-free solutions of enzymes. First, the detection of a response of the cells (`electrical window') is a prerequisite for testing at least three parameters: frequency, amplitude and treatment time, besides reproducible biological conditions. The `state-of-the-art' of this fast developing direction of bioelectrochemistry can be characterized in the following way: the results from several laboratories of (a) cell proliferation, (b) ion transport, (c) activation of several enzymes (Na,K-ATPase), (d) increase of certain protein concentrations (heat-shock protein hsp70) are more or less in agreement. Unfortunately, there are discrepancies between no less than 7 labs in the gene expression of c-myc, c-fos histone 2B, -actin, URA-3 and others, especially for low fields (<0.05 mT), e.g., in HL60 cells! The reason why seems to be: (1) differences in the most suitable isolation procedure, (2) interferences in the case of too low magnetic flux and (3) too small ranges of parameters have been measured. Today, three open problems must be pointed out: (A) What is the physiological causality for specific `electrical windows' and their positive or negative efficacy? (B) What are the biochemical targets for either magnetic or electric fields or both? (C) What is the influence of electrical and (or) thermal noise on field efficiency?</div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 2","pages":"Pages 355-360"},"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)00012-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21247871","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: 134

Calcium channels, potassium channels and membrane potential of smooth muscle cells of human allantochorial placental vessels 人胎盘尿囊膜血管平滑肌细胞的钙通道、钾通道和膜电位

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00020-3

Andrée Guiet-Bara , Bissiriou Ibrahim , Jean Leveteau , Michel Bara

{"title":"Calcium channels, potassium channels and membrane potential of smooth muscle cells of human allantochorial placental vessels","authors":"Andrée Guiet-Bara , Bissiriou Ibrahim , Jean Leveteau , Michel Bara","doi":"10.1016/S0302-4598(99)00020-3","DOIUrl":"10.1016/S0302-4598(99)00020-3","url":null,"abstract":"<div>The membrane potential (Um), the main factor of the excitation–contraction coupling, of human allantochorial placental vascular smooth muscle cells (VSMCs) has been previously shown to depend on voltage-sensitive K+ channels. These channels were blocked by high external K+. To characterize other channels which regulated Um, various constrictor or/and vasodilators and channel blockers were used. Serotonin depolarized VSMCs, in normal medium, but induced a more marked depolarization in VSMCs predepolarized by high external K+. This depolarization was inhibited by nifedipine, a blocker of voltage-gated Ca2+ channels. Acetylcholine, sodium nitroprusside (without effect on Um in normal medium), hyperpolarized the predepolarized-high K+ medium VSMCs. This hyperpolarization was inhibited after addition of charybotoxin (a blocker of Ca2+-activated K+ channels) or/and glibenclamide (a blocker of ATP-sensitive K+ channels). A similar effect was obtained with isoproterenol. These results indicated that membrane potential of human placental allantochorial VSMCs was regulated by voltage-gated, Ca2+- and ATP-sensitive K+ channels and by voltage-dependent Ca2+ channels.</div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 2","pages":"Pages 407-413"},"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)00020-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21247198","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

Quantum dissipation and Neural Net Dynamics 量子耗散和神经网络动力学

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00036-7

Eliano Pessa , Giuseppe Vitiello

引用次数: 24

Electromagnetic-field-induced oscillations of the lipid domain structures in the mixed membranes 混合膜中脂质结构的电磁场诱导振荡

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00040-9

Alexey N. Goltsov

引用次数: 15

Influence of additives on the protoplasts electrofusion 添加剂对原生质体电融合的影响

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00045-8

Zhiyu Jiang, Mingyan Wang, Wei Wang

引用次数: 3

Effects of ELF capacitively coupled weak electric fields on metabolism of 6B1 cells 极低频电容耦合弱电场对6B1细胞代谢的影响

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00024-0

Xing Wang , Aihua Zhou , Man Liu , Haiying Yu , Lijun Pang , Mingyao Zhu , Leiguang Wang , Hermann Berg

引用次数: 4

Microtubules: strange polymers inside the cell 微管:细胞内奇怪的聚合物

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00011-2

H. Bolterauer, H.-J. Limbach, J.A. Tuszyński

引用次数: 12

Detection of the ΔF508 mutation in the CFTR gene by means of time-resolved fluorescence methods 用时间分辨荧光法检测CFTR基因ΔF508突变

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00052-5

S Kirschstein , S Winter , D Turner , G Löber

引用次数: 5

Electroporation-mediated topical delivery of vitamin C for cosmetic applications1 用于化妆品应用的电穿孔介导的维生素C局部递送1

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-05-01 DOI: 10.1016/S0302-4598(99)00026-4

Lei Zhang , Sheldon Lerner , William V Rustrum , Günter A Hofmann

{"title":"Electroporation-mediated topical delivery of vitamin C for cosmetic applications1","authors":"Lei Zhang , Sheldon Lerner , William V Rustrum , Günter A Hofmann","doi":"10.1016/S0302-4598(99)00026-4","DOIUrl":"https://doi.org/10.1016/S0302-4598(99)00026-4","url":null,"abstract":"<div>It is now medically recognized that sagging skin and other signs of degenerative skin conditions, such as wrinkles and age spots, are caused primarily by oxy-radical damage. Vitamin C (Vit. C), in the form of l-ascorbic acid (Asc), is the one vitamin that can accelerate wound healing, protect fatty tissues from oxidation damage, and play an integral role in collagen synthesis. It is known that the lipid-rich stratum corneum (SC) is a highly resistant barrier to chemical agents penetrating into the skin. This report describes the first feasibility study of electroporation-mediated topical delivery (EMTD) of Asc for potential cosmetic applications. Both a cream formulation (20% Asc) and a crystal suspension (33% Asc) were applied respectively to human cadaver skin and fresh surgical skin. Six exponential pulses at 60 or 100 V and pulse lengths of 2.7–30 ms were selected. EMTD was more effective on fresh human skin than on human cadaver skin. For both skin models, EMTD with cream resulted in a greater enhancement of Vit. C penetration than with suspension. The distribution of electrical fields through the SC, epidermis, and dermis is demonstrated in computer simulation. Assuming that this fresh skin model and certain experimental conditions simulate projected in vivo applications, EMTD of Vit. C may represent an alternative method to ameliorate skin aging.</div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 2","pages":"Pages 453-461"},"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)00026-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72247899","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: 66