Zeitschrift fur Naturforschung. Section C, Biosciences最新文献_第5页

[Molecular pharmacological investigation of medicinal plant substances. II. Inhibition of acetylcholinesterase by monoterpene derivatives in vitro]. 药用植物物质的分子药理学研究。2单萜衍生物对乙酰胆碱酯酶的体外抑制作用[j]。

Zeitschrift fur Naturforschung. Section C, Biosciences Pub Date : 1985-03-01 DOI: 10.1515/znc-1985-3-401

L Gracza

引用次数: 22

Small-angle X-ray and light scattering studies on the influence of Mg2+ ions on the structure of the RNA from bacteriophage MS2. Mg2+离子对噬菌体MS2中RNA结构影响的小角度x射线和光散射研究

Zeitschrift fur Naturforschung. Section C, Biosciences Pub Date : 1985-03-01 DOI: 10.1515/znc-1985-3-417

G Ribitsch, R De Clercq, W Folkhard, P Zipper, J Schurz, J Clauwaert

{"title":"Small-angle X-ray and light scattering studies on the influence of Mg2+ ions on the structure of the RNA from bacteriophage MS2.","authors":"G Ribitsch, R De Clercq, W Folkhard, P Zipper, J Schurz, J Clauwaert","doi":"10.1515/znc-1985-3-417","DOIUrl":"https://doi.org/10.1515/znc-1985-3-417","url":null,"abstract":"The influence of Mg2+ ions on the secondary and tertiary structure of the RNA from bacteriophage MS2 was investigated by small-angle X-ray scattering and light scattering and by sedimentation experiments. The analysis of the outer part of the X-ray scattering curve obtained at low temperature in the absence of Mg2+ yielded a cross-section radius of gyration of 0.88 nm and a mass per unit length of 1720 g mol-1 nm-1. Very similar values for these parameters, which refer to the secondary structure of the RNA molecule, were also derived from the X-ray scattering curves obtained in the presence of different amounts of Mg2+ (0.07 to 1 ions per nucleotide). On the contrary, the inner part of the X-ray scattering curves turned out to be highly dependent on the Mg2+ concentration: the cross-section radius of gyration and the mass per unit length, which were determined from the scattering curves at small angles as parameters related to the tertiary structure of the RNA, amounted to 3.11 nm and 4000 g mol-1 nm-1, respectively, in the absence of Mg2+ and increased significantly upon raising the concentration of Mg2+. The increase of these structural parameters was found to be accompanied by a decrease of the overall radius of gyration (as revealed indirectly by X-ray scattering and directly by light scattering measurements) and by an increase of the sedimentation coefficient. The results from the investigations of the RNA at low temperature clearly establish the existence of double-stranded structures down to very low Mg2+ concentrations as well as the occurrence of Mg2+ induced changes of the tertiary structure.(ABSTRACT TRUNCATED AT 250 WORDS)","PeriodicalId":23914,"journal":{"name":"Zeitschrift fur Naturforschung. Section C, Biosciences","volume":"40 3-4","pages":"234-41"},"PeriodicalIF":0.0,"publicationDate":"1985-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znc-1985-3-417","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15114437","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

Control of the activity of brain synaptosome-associated acetylcholinesterase by acidic phospholipids. 酸性磷脂对脑突触体相关乙酰胆碱酯酶活性的控制。

Zeitschrift fur Naturforschung. Section C, Biosciences Pub Date : 1985-01-01 DOI: 10.1515/znc-1985-1-219

S Tsakiris

{"title":"Control of the activity of brain synaptosome-associated acetylcholinesterase by acidic phospholipids.","authors":"S Tsakiris","doi":"10.1515/znc-1985-1-219","DOIUrl":"https://doi.org/10.1515/znc-1985-1-219","url":null,"abstract":"Incubation of synaptosomal plasma membranes (SPM) with liposomes of phosphatidylserine (PS), phosphatidylinositol (PIN) or phosphatidylglycerol (PGL), led to an increase of acetylcholinesterase (AchE) activity at concentrations of 0.1-1 mumol phospholipids per mg SPM protein. The use of higher concentrations (1-7 mumol/mg protein), however, led to a progressive inhibition of the activity with respect to the maximal percentage of enzyme stimulation. To explain the enzyme stimulation by the acidic phospholipids, AchE was solubilized with the detergent Lubrol-PX and showed no change in the enzyme activity at any PS, PIN or PGL concentration used, indicating that these compounds do not act on the protein molecule directly. Arrhenius plots of AchE activities in untreated SPM (control), exhibited a break point at 23 degrees C, which was decreased to 16-17 degrees C in PS-treated SPM. Moreover, the Arrhenius activation energy (Ea) value in PS-treated SPM was increased related to the Ea below the break point in the control. These results indicate that acidic phospholipids do not act on AchE directly, but indirectly, affecting the membrane fluidity probably. Such modifications of interactions between lipid and AchE may control physiological processes in the central nervous system.","PeriodicalId":23914,"journal":{"name":"Zeitschrift fur Naturforschung. Section C, Biosciences","volume":"40 1-2","pages":"97-101"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znc-1985-1-219","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15105520","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: 8

Purification and properties of adenosine kinase from rat liver: separation from deoxyadenosine kinase activity. 大鼠肝中腺苷激酶的纯化及性质:脱氧腺苷激酶活性的分离。

Zeitschrift fur Naturforschung. Section C, Biosciences Pub Date : 1985-01-01 DOI: 10.1515/znc-1985-1-209

A K Drabikowska, L Halec, D Shugar

{"title":"Purification and properties of adenosine kinase from rat liver: separation from deoxyadenosine kinase activity.","authors":"A K Drabikowska, L Halec, D Shugar","doi":"10.1515/znc-1985-1-209","DOIUrl":"https://doi.org/10.1515/znc-1985-1-209","url":null,"abstract":"Ion exchange and affinity chromatography techniques, similar to those previously reported for purification of adenosine kinase from human placenta, were applied to purification of rat liver adenosine kinase. The enzyme, purified 400-fold in 41% yield, was homogeneous on SDS-polyacrylamide gel electrophoresis, with a molecular weight of 52000. It specific activity, 18 mumol/min/mg protein, is the highest hitherto reported for this enzyme from mammalian sources. Chromatography on DEAE-cellulose removed about 98% of the phosphorylating activity towards 2'-deoxyadenosine present in the initial pH-treated liver extract. The final preparation exhibited only minimal activity (approximately 1.5%) under optimal conditions (pH 7.5) vs 2'-deoxy-adenosine, the lowest yet reported for such a preparation, with a Km of 670 microM, as compared to 0.3 microM for adenosine. The residual activity towards deoxyadenosine is considered an intrinsic property of the purified adenosine kinase and, in fact, phosphorylation of adenosine was inhibited competitively by deoxyadenosine, with a Ki of 70 microM. Competitive inhibition was also exhibited by cordycepin (3'-deoxyadenosine) with a Ki of 150 microM. A more potent competitive inhibitor was tubercidin, the Ki for which was 1.9 microM.","PeriodicalId":23914,"journal":{"name":"Zeitschrift fur Naturforschung. Section C, Biosciences","volume":"40 1-2","pages":"34-41"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znc-1985-1-209","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14121117","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: 10

Phosphatidylinositol-specific phospholipase C from bovine blood platelets. Inhibition by calmodulin-inhibitors--activation by ATP and ADP. 牛血小板磷脂酰肌醇特异性磷脂酶C。钙调素抑制剂的抑制作用——ATP和ADP的激活作用。

Zeitschrift fur Naturforschung. Section C, Biosciences Pub Date : 1985-01-01 DOI: 10.1515/znc-1985-1-214

H Benedikter, G Knopki, P Renz

引用次数: 0

Higher cardol homologues (5-alkenylresorcinols) from rye affect the red cell membrane-water transport. 黑麦中较高含量的醇同系物(5-烯基间苯二酚)影响红细胞膜-水运输。

Zeitschrift fur Naturforschung. Section C, Biosciences Pub Date : 1985-01-01 DOI: 10.1515/znc-1985-1-216

A Kozubek

引用次数: 10

Photodestruction of Propionibacterium acnes porphyrins. 痤疮丙酸杆菌卟啉的光破坏。

Zeitschrift fur Naturforschung. Section C, Biosciences Pub Date : 1985-01-01 DOI: 10.1515/znc-1985-1-224

T B Melø, G Reisaeter, A Johnsson, M Johnsson

引用次数: 10

Occurrence of "stress"-proteins in yeast after heat-shock, acrylonitrile treatment and during the stationary growth phase. 酵母在热休克、丙烯腈处理和固定生长阶段出现“应激”蛋白。

Zeitschrift fur Naturforschung. Section C, Biosciences Pub Date : 1985-01-01 DOI: 10.1515/znc-1985-1-207

U Pfeffer, B Schulz-Harder

引用次数: 3

Production of four interfacial active rhamnolipids from n-alkanes or glycerol by resting cells of Pseudomonas species DSM 2874. 假单胞菌DSM 2874静息细胞由正构烷烃或甘油合成四种界面活性鼠李糖脂。

Zeitschrift fur Naturforschung. Section C, Biosciences Pub Date : 1985-01-01 DOI: 10.1515/znc-1985-1-213

C Syldatk, S Lang, U Matulovic, F Wagner

{"title":"Production of four interfacial active rhamnolipids from n-alkanes or glycerol by resting cells of Pseudomonas species DSM 2874.","authors":"C Syldatk, S Lang, U Matulovic, F Wagner","doi":"10.1515/znc-1985-1-213","DOIUrl":"https://doi.org/10.1515/znc-1985-1-213","url":null,"abstract":"In a simple phosphate buffer or a sodium chloride solution resting cells of Pseudomonas spec. DSM 2874 produced up to 15 g/l of different rhamnolipids. The rhamnolipid composition of the organic crude extract depended on the temperature during the cultivation and on the C-source. The optimal sodium chloride concentration for rhamnolipid formation was about 100 mM/l and the optimal phosphate buffer concentration about 65 mM/l. The optimal pH-value for the production of rhamnolipids from n-alkanes or glycerol was in the range pH 6.0-7.2. While rhamnolipid formation with glycerol as the sole C-source showed a wide optimum ranging from 27 degrees up to 37 degrees C, production of rhamnolipids from n-alkanes had a sharp optimum at 37 degrees C. The addition of multivalent cations, different N-sources and EDTA caused an inhibition of rhamnolipid formation, while the n-alkane concentration had no influence. Specific rhamnolipid formation decreased with increasing cell concentration. Various C-sources were suitable for the formation of rhamnolipids by resting cells of Pseudomonas spec. DSM 2874. Yields, which were comparable to those obtained on n-alkanes or glycerol, were found for stearic acid, fatty alcohols and vegetable oils. A study of the time course of glycolipid production of resting cells was carried out in a 20 1-bioreactor with an intensor system and with n-tetradecane as the sole C-source.","PeriodicalId":23914,"journal":{"name":"Zeitschrift fur Naturforschung. Section C, Biosciences","volume":"40 1-2","pages":"61-7"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znc-1985-1-213","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15037800","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: 145

Kinetics of calcium-induced fusion of cell-size liposomes with monolayers in solutions of different osmolarity. 钙诱导细胞大小脂质体与单层膜在不同渗透压溶液中的融合动力学。

Zeitschrift fur Naturforschung. Section C, Biosciences Pub Date : 1985-01-01 DOI: 10.1515/znc-1985-1-218

N Stoicheva, I Tsoneva, D S Dimitrov, I Panaiotov

{"title":"Kinetics of calcium-induced fusion of cell-size liposomes with monolayers in solutions of different osmolarity.","authors":"N Stoicheva, I Tsoneva, D S Dimitrov, I Panaiotov","doi":"10.1515/znc-1985-1-218","DOIUrl":"https://doi.org/10.1515/znc-1985-1-218","url":null,"abstract":"The effects of osmolarity, calcium concentration and cell-size liposomes in the subphase on the surface tension of phospholipid monolayers were investigated. The monolayers were spread from chloroform solutions of phosphatidic acid at air/water solution interface. The liposomes (of average diameter 3 micron) were formed from phosphatidic acid/egg lecithin (1:2) mixtures in water or 0.1 M water solutions of sucrose. For this system there were critical concentrations of calcium ions to produce a large reduction of the monolayer surface tension. The threshold calcium concentrations depended upon the sucrose concentration in the subphase. Without sucrose the threshold calcium concentration was 8 mM, while for isoosmotic sucrose solutions (0.1/0.1 M in/out of liposome) it was 14 mM. It sharply increased to 28 mM CaCl2 at sucrose concentration difference across the liposome membrane 0.02 M and decreased to 26 mM, 19 mM, and 18 mM with further increase of that difference to 0.04 M, 0.06 M, and 0.08 M, respectively. The rate of monolayer surface tension decrease was measured as a function of time at 30 mM CaCl2 and different sucrose concentrations in the subphase solution. The initial rates at first decreased with increasing the osmotic pressure and after that they increased. The minimum occurred at sucrose concentration gradient across the liposome membrane 0.02 M, i.e., at the point of maximum threshold calcium concentration required for large decrease of the monolayer surface tension. These facts may be explained by recent theories of dynamics of adhesion, instability and fusion of membranes modeled as thin films.","PeriodicalId":23914,"journal":{"name":"Zeitschrift fur Naturforschung. Section C, Biosciences","volume":"40 1-2","pages":"92-6"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/znc-1985-1-218","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15037803","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: 3