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1985 (179)
1Author    Rainer Pensl, Rainer SiitfeldRequires cookie*
 Title    Occurrence of 3,4-Diacetoxybutinylbithiophene in Tagetes patula and Its Enzymatic Conversion  
 Abstract    S e p tem b e r 6/O c to b e r 11, 1984 T hiophene D erivatives, A cetate E sterases, Tagetes patula, 3 ,4 -D ia c eto x y b u tin y lb ith io p h en e , 3,4-H ydroxybutinylbithiophene 3,4-D iacetoxybutinylbithiophene w as found to occur in c o n sid erab le a m o u n ts in roots and hypocotyls o f young Tagetes seedlings. T his co m p o u n d was converted enzym atically to 3,4-di-hydroxybutinylbithiophene by c rude extracts from this plant. E xperim ents p e rfo rm e d w ith enzyme preparations from plants o f differen t stages o f d ev elo p m en t su p p o rte d th e existence o f two position-specific, subsequently w orking d ith io p h e n e acetate esterases. It is suggested th a t 3-hydroxy-4-acetoxybutinylbithiophene is th e in te rm ed iate p ro d u c t, form ed by an highly specific 3 4-diaceto x y b u tin y lb ith io p h en e: 4-acetate esterase. 
  Reference    Z. Naturforsch. 40c, 3 (1985); received 
  Published    1985 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0003.pdf 
 Identifier    ZNC-1985-40c-0003 
 Volume    40 
2Author    Fred Siewek, Karl HerrmRequires cookie*
 Title    Isomeric Di-C-glycosylflavones in Fig (Ficus carica L.)  
 Abstract    ebensm ittelchem ie der U n iv ersität H annover, W u n sto rfer Str. 14, D-3000 H annover 91 and Lutz Grotjahn and Victor Wray Gesellschaft für B iotechnologische F orschung, M a sc h ero d e r W eg 1, D -3300 B raunschw eig Z. Naturforsch. 4 0 c , 8 -1 2 (1985); received S e p tem b e r 6, 1984 Apigenin-di-C-glycosides, Isolation, Iden tificatio n , Q u a n tita tiv e D e te rm in a tio n , Ficus carica Two isomeric C-glycosides o f a pigenin (a p ig e n in -6-C -glucosyl-8-C -a ra b in o sid e (schaftoside), apigenin-6-C -arabinosyl-8-C -glucoside (isoschaftoside)) w ere isolated from leaves o f Ficus carica with preparative HPLC. The glycosides were identified by UV-, 'H -N M R -, l3C -N M R -sp e ctro sc o p y and FAB-M S. T heir concentration in fruits and leaves w ere d e te rm in e d by g ra d ie n t H P L C on reversed p h ase m aterial. 
  Reference    Z. Naturforsch. 40c, 8 (1985) 
  Published    1985 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0008.pdf 
 Identifier    ZNC-1985-40c-0008 
 Volume    40 
3Author    Isabella Koch-Heitzmann, W. Ulf, Schultze, Franz-C CzyganRequires cookie*
 Title    Untersuchungen an Kalluskulturen von Melissa officinalis L., II Über wasserdampfflüchtige Diterpenkohlenwasserstoffe in nicht differenzierten Oberflächenkulturen Investigations on Callus Cultures of Melissa officinalis L., II Votile D iterpene Hydrocarbons in Not Differentiated Static Cultures  
 Abstract    P harm azeutische Biologie der U niversität, D -8700 W ü rzb u rg , M ittle rer D allen -bergweg 64 Z. N aturforsch. 4 0 c , 1 3 -2 0 (1985); received A ugust 1 3 /O cto b er 15, 1984 Plant Tissue C ulture, Volatile D iterpene H ydrocarbons, C o m b in e d G a s-C h ro m a to g ra p h y /M a s s Spectrom etry, Melissa officinalis L. D ehydroabietane and an other diterp en e hydro carb o n , b ein g still u n id e n tifie d , w ere found in the steam distillates o f callus cultures o f Melissa officinalis. T h e relativ e p ro p o rtio n s o f th ese tw o diterpenes changed considerably during the course o f a c u ltiv atio n passage. W ith a d v an cin g age o f the cells they shifted gradually tow ards d e h y d ro ab ieta n e. C u ltu re s bein g exposed to c o n ti­ nuous light showed the sam e com position o f th eir steam d istillate s as c u ltu res w hich w ere raised in the dark. 
  Reference    Z. Naturforsch. 40c, 13 (1985) 
  Published    1985 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0013.pdf 
 Identifier    ZNC-1985-40c-0013 
 Volume    40 
4Author    H.-A Arfmann, W. Kohl, V. WrayRequires cookie*
 Title    Effect of 5-Azacytidine on the Formation of Secondary Metabolites in Catharanthus roseus Cell Suspension Cultures  
 Abstract    Forschung m bH , M a sc h ero d e r W eg 1, 3300 B raunschw eig, Bundesrepublik D eutschland Z. N aturforsch. 40 c, 21 —25 (1985); received July 1 6/O ctober 17, 1984 Catharanthus roseus, Cell Suspension C ultures, 5-A zacytidine, S econdary M e tab o lism A cell suspension culture o f C atharanthus roseus was tre a te d d u rin g the grow th p h a se w ith the nucleoside analogue 5-azacytidine, a pow erful in d u cer o f cell d iffe re n tia tio n , as ev idenced w ith anim al and hum an cell lines. A fter induction the cell c u ltu re w as fu rth e r in cu b a te d in a production m edium in the absence o f the inducer for 10 days. T h e e x tra ctio n o f th e freeze d ried cells and analysis by high perform ance liquid c h ro m a to g ra p h y show ed an a d d itio n a l intense peak in the elution profile, not present in extracts o f u n trea te d cells. T h e stru c tu re o f th e new ly synthesized m etabolite, elucidated by m ass spectrom etry and 'H an d 13C N M R , was a lig n an type com pound, lirioresinol B mono-/?-D-glucoside. T his c o m p o u n d has h ith e rto not been found in Catharanthus roseus plants or cell cultures. 
  Reference    Z. Naturforsch. 40c, 21 (1985) 
  Published    1985 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0021.pdf 
 Identifier    ZNC-1985-40c-0021 
 Volume    40 
5Author    Ulrich Pfeffer, Bernd Schulz-HarderRequires cookie*
 Title    Occurrence of "Stress"-Proteins in Yeast after Heat-Shock, Acrylonitrile Treatment and during the Stationary Growth Phase  
 Abstract    Freie U niversität Berlin, F achbereich Biologie, In stitu t fü r B io ch em ie und M o le k u la rb io lo g ie, E hrenbergstraße 2 6 -2 8 , D-1000 Berlin 33 Z. N aturforsch. 4 0 c , 26 —28 (1985); received S ep tem b er 17, 1984 Heat-Shock, Acrylonitrile, R ibonuclease, Saccharom yces cerevisiae The response o f yeast cells to different kinds o f " stress" is n o t id en tical. C ells o f th e sta tio n a ry growth phase synthesize three new proteins o f m o le c u la r w eights 68, 27 an d 24 kD , c o m p a re d with cells o f the exponential grow th phase, w hile h e at-sh o ck ed cells e x h ib it new p ro tein s o f 100, 90, 84, 70 and 24 kD. A fter treatm en t w ith acrylonitrile tw o new p ro tein s w ith m o le c u la r w eights o f 70 and 46 kD appear. How ever, all three kinds o f " stress" lead to th e in d u c tio n o f a rib o ­ nuclease. 
  Reference    Z. Naturforsch. 40c, 26 (1985) 
  Published    1985 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0026.pdf 
 Identifier    ZNC-1985-40c-0026 
 Volume    40 
6Author    Reinhard Steinkamp, Heinz RennenbergRequires cookie*
 Title    Degradation of Glutathione in Plant Cells: Evidence against the Participation of a y-Glutamyltranspeptidase  
 Abstract    A ugust 31/O c to b e r 4, 1984 Tobacco, G lutathione C atabolism , y-G lutam ylcysteine, y -G lu ta m y ltra n sp e p tid a se , y-G lutam yl-cyclotransferase W hen y-glutam yltranspeptidase activity in tobacco cells w as m ea su re d using th e a rtificial substrate y-glutam yl-/?-nitroanilide, lib eratio n o f p -n itro a n ilin e w as not re d u c e d , b u t stim u la te d by addition o f glutathione. T herefore, g lu tath io n e was not acting as a d o n a to r, b u t as an a cc ep to r o f y-glutamyl m oieties in the assay m ixture, suggesting th a t y -g lu ta m y ltran sp ep tid ase is n o t participating in degradation o f glutathione. F eed in g e x p erim e n ts w ith [^S -cy sJg lu tath io n e s u p ­ ported this conclusion. W hen tobacco cells w ere su p p lied w ith th is p e p tid e as sole su lfu r source, glutathione and y-glutam ylcysteine were the only labelled c o m p o u n d s fo und inside th e cells. T h e low rate o f uptake o f g lutathione ap parently prevented th e a c c u m u la tio n o f m e a su ra b le a m o u n ts o f radioactivity in the cysteine pool. A y-glutam ylcyclotransferase, resp o n sib le fo r th e conversion o f y-glutamylcysteine to 5-oxo-proline and cysteine was found in a m m o n iu m su lfate p re cip ita te s o f tobacco cell hom ogenates. T he enzym e show ed high a ctiv ities w ith y -g lu ta m y lm eth io n in e an d y-glutamylcysteine, but not w ith other y -g lutam yldipeptides o r g lu ta th io n e . F ro m these an d previously published experim ents [(R ennenberg et al., Z. N a tu rfo rsc h . 3 5 c , 7 0 8 -7 1 1 (1980)], it is concluded that glutathione is degraded in tobacco cells via th e follow ing p a th w ay : y-glu-cys-gly — > y-glu-cys -> • 5-oxo-proline -* glu. 
  Reference    Z. Naturforsch. 40c, 29 (1985); received 
  Published    1985 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0029.pdf 
 Identifier    ZNC-1985-40c-0029 
 Volume    40 
7Author    AlicjaK. Drabikowska, Lidia Halec, D. Avid ShugarRequires cookie*
 Title    Purification and Properties of Adenosine Kinase from Rat Liver: Separation from Deoxyadenosine Kinase Activity  
 Abstract    A denosine Kinase, P urification, K inetics, C o m p etitiv e In h ib itio n Ion exchange and affinity c h ro m a to g ra p h y tech n iq u es, sim ila r to those previously re p o rte d for purification o f adenosine kinase from h u m an placenta, w ere a p p lie d to p u rific atio n o f ra t liver adenosine kinase. T he enzym e, p u rifie d 400-fold in 41% yield, was hom o g en eo u s on SD S-polyacrylam ide gel electrophoresis, w ith a m o le c u la r w eight o f 52000. It specific activity, 18 (im ol/m in/m g protein, is the highest h ith e rto re p o rte d for this enzym e from m a m m a lia n sources. C hrom atography on D EA E-cellulose rem oved a b o u t 98% o f the p h o sp h o ry la tin g activity towards 2 '-deoxyadenosine present in the initial p H -tre a te d liver extract. T h e final p re p a ra tio n exhibited only m inim al activity (~ 1.5%) u n d e r o p tim a l conditions (pH 7.5) vs 2 '-d eo x y -adenosine, the lowest yet reported for such a p re p a ra tio n , w ith a K m o f 670 (iM, as c o m p a red to 0.3 (iM for adenosine. The residual activity tow ards d eoxyadenosine is considered an in trin sic p ro p e rty o f th e purified adenosine kinase and, in fact, p h o sp h o ry la tio n o f adenosine w as in h ib ite d com p etitiv ely by deoxyadenosine, w ith a K l o f 70 (JM. C o m p etitiv e in h ib itio n was also e x h ib ited by cord y cep in (3'-deoxyadenosine) w ith a K t o f 150 hm. A m ore p o te n t com p etitiv e in h ib ito r was tu b e rc id in , the for which was 1.9 |iM. 
  Reference    Z. Naturforsch. 40c, 34—41 (1985); received A ugust 14 1984 
  Published    1985 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0034.pdf 
 Identifier    ZNC-1985-40c-0034 
 Volume    40 
8Author    Gerd GädeRequires cookie*
 Title    Amino Acid Composition of Cockroach Hypertrehalosaemic Hormones  
 Abstract    U niversität D üsseldorf, U n iv e rsitä tsstraß e 1, D -4000 D ü s se ld o rf 1, B undesrepublik D eutschland 
  Reference    Z. Naturforsch. 40c, 42 (1985) 
  Published    1985 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0042.pdf 
 Identifier    ZNC-1985-40c-0042 
 Volume    40 
9Author    Nanao Hayashi, Akihiko Nishi, TadayukiM. Urakam, KazuyukiM. Aeshim, Hisashi KomaeRequires cookie*
 Title    The Scent Substances of Pierid Butterflies (Hebomoia glaucippe Linnaeus) and the Volatile Components of Their Food Plants (Crataeva religiosa Forst.)  
 Abstract    , F acu lty o f In teg rated A rts and Sciences, H iro sh im a U niversity, Hiroshim a 730, Japan and Takashi Sakao D epartm ent of Chem istry, Faculty o f E ducation, K ag o sh im a U n iv ersity , K a g o sh im a 890, Ja p a n Z. Naturforsch. 4 0 c , 4 7 -5 0 (1985); received A ugust 1 4 /O c to b e r 24, 1984 Hebomoia glaucippe, Pierid Butterfly, Scent Secretion, E-/?-O cim ene, Crataeva religiosa, Essential Oil The scent secretions o f two subspecies o f H ebom oia glaucippe, w hich a re p ie rid b u tterflies, and the essential oils o f their food plant w ere investigated by m eans o f G C a n d G C -M S . T h e scent substances of either subspecies are found to be only £ -/?-ocim ene, an d th e v o latile co m p o n en ts o f Crataeva religiosa were identified as 2-hexanal, 3 -h e x e n -l-o l, p -c y m e n e, lim onene, linalool, a-ionone, and /?-ionone. E lectroantennogram (E A G) w ere reco rd ed w ith th e an te n n ae o f a d u lt m ale and female butterflies. It was found th a t EA G responses o f m ale to £-/?-ocim ene w ere greater than those o f females. 
  Reference    Z. Naturforsch. 40c, 47 (1985) 
  Published    1985 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0047.pdf 
 Identifier    ZNC-1985-40c-0047 
 Volume    40 
10Author    Christoph Syldatk, Siegmund Lang, FritzW. Agner, Victor Wray, Ludger WitteRequires cookie*
 Title    Chemical and Physical Characterization of Four Interfacial-Active Rhamnolipids from Pseudomonas spec. DSM 2874 Grown on /i-Alkanes  
 Abstract    Four extracellular glycolip id s p rod u ced under g r o w th -lim itin g c o n d itio n s w ere iso la ted from the culture broth o f Pseudomonas spec. D SM 2874. A fter p u r ific a tio n by c o lu m n and th ick -la y er chrom atography they were id en tified as a n io n ic rh a m n o lip id s. 'H and '3C -N M R stu d ie s sh o w e d that two o f these, /? (/? (2 -0 -a -L -rh a m n o p y ra n o sy lo x y)d eca n o y l)d eca n o ic a cid and /?(/?(2-0-a-L -rh a m n o p y ran osyl-x-L -rh am n op yran osyloxy)d ecan oyloxy)d ecan oic acid , w ere id en tica l w ith c o m ­ pounds described previously, w h ile the other m ore h y d r o p h ilic c o m p o u n d s, /? (2 -0 -a -L -r h a m n o -p yranosyloxy)decanoic acid and /? (2 -0 -a -L -r h a m n o p y ra n o sy l-ix -L -rh a m n o p y ra n o sy lo x y)d e ca n o ic acid, were new com pounds. Surface and interfacial activity o f the organic crude extract and o f the purified com ponents were determined in different aqueous solutions. The pH -dependence o f surface and interfacial properties o f the two previously described rham nolipids (4, 20. 23) were exam ined in Teorell-Stenhagen-buffer (supplemented with 10% N aC l) at pH 3.0 and pH 9.0. All rham nolipids reduced the surface-tension from 72 to about 30 m N / m and the interfacial-tension from 42 to about 1 m N /m . The critical m icelle concentrations were o f the order o f 5 to 200 mg/1 depending on the structure o f the molecule. 
  Reference    Z. Naturforsch. 40c, 51—60 (1985); received August 20 1984 
  Published    1985 
  Keywords    Pseudomonas, Interfacial-Active, Rham nolipids, «-Alkanes, Structure-Eludication 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0051.pdf 
 Identifier    ZNC-1985-40c-0051 
 Volume    40 
11Author    C. Syldatk, S. Lang, U. Matulovic, F. W. AgnerRequires cookie*
 Title    Production of Four Interfacial Active Rhamnolipids from /i-Alkanes or Glycerol by Resting Cells of Pseudomonas species DSM 2874  
 Abstract    In a simple phosphate buffer or a sodium chloride solution resting cells o f Pseudom onas spec. DSM 2874 produced up to 15 g/1 o f different rham nolipids. The rham nolipid com position o f the organic crude extract depended on the temperature during the cultivation and on the C-source. The optimal sodium chloride concentration for rham nolipid form ation was about 100 mM/1 and the optimal phosphate buffer concentration about 65 mM/1. The optim al pH -value for the production o f rhamnolipids from «-alkanes or glycerol was in the range pH 6.0 -7 . 2 . W hile rhamnolipid formation with glycerol as the sole C-source show ed a w ide optim um ranging from 27 ° up to 37 °C, production o f rhamnolipids from «-alkanes had a sharp optim um at 37 °C. The addition o f multivalent cations, different N -sources and E D T A caused an inhibition o f rhamnolipid formation, while the «-alkane concentration had no influence. Specific rham nolipid formation decreased with increasing cell concentration. Various C-sources were suitable for the formation o f rhamnolipids by resting cells o f Pseudom onas spec. D S M 2874. Yields, which were comparable to those obtained on «-alkanes or glycerol, were found for stearic acid, fatty alcohols and vegetable oils. A study o f the time course o f glycolipid production o f resting cells was carried out in a 20 1-biorcactor with an intensor system and with «-tetradecane as the sole C-source. 
  Reference    Z. Naturforsch. 40c, 61—67 (1985); received August 2 0 /0 c to b e r 23 1984 
  Published    1985 
  Keywords    Pseudomonas, Interfacial-Active, Rham nolipids, «-Alkanes, Resting Cells 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0061.pdf 
 Identifier    ZNC-1985-40c-0061 
 Volume    40 
12Author    Hermann Benedikter, Gisela Knopki, Paul RenzRequires cookie*
 Title    Phosphatidylinositol-Specific Phospholipase C from Bovine Blood Platelets. Inhibition by Calmodulin-Inhibitors — Activation by ATP and ADP  
 Abstract    The phospholipase C-activity in crude extracts o f bovine blood platelets is strongly inhibited by the calmodulin-inhibitors fluphenazine and calm idazolium in the m M range, and activated by ATP and ADP, but not by AMP. The activating effect is also shown by the nonhydrolysable ATP-and ADP-analogs a,/?-and /?,y-methyleneadenosine 5 '-triphosphate and a,/?-m ethylene-adenosine 5'-diphosphate, thus indicating that it is an allosteric effect. The stim ulation o f the phospholipase C-activity by ATP is also detectable in som e partially purified fractions o f the crude platelet extract, but it is abolished on further purification o f the enzyme. 
  Reference    Z. Naturforsch. 40c, 68—7 (1985); received April 24/Septem ber 18 1984 
  Published    1985 
  Keywords    Phospholipase C, Bovine Blood Platelets, Phosphatidylinositol, Allosteric A ctivation, C alm odulin 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0068.pdf 
 Identifier    ZNC-1985-40c-0068 
 Volume    40 
13Author    R. B. Mellor, T.M I E Christensen, S. Bassarab, D. W. ErnerRequires cookie*
 Title    Phospholipid Transfer from ER to the Peribacteroid Membrane in Soybean Nodules  
 Abstract    ATPase, Glycine max, Membrane F low /D ifferentiation, P hosp holipid, Rhizobium japonicum Organelle membranes subfractionated from nodules o f Glycine m ax differed in lipid com po­ sition. Of the enzymes assembling phospholipids, choline kinase (EC 2.7.1.32) was recovered in the cytoplasmic fraction whereas C D P choline 1,2-diacylglyceride choline phosphotransferase (EC 2.7.8.2) was located in the ER. W hen methyl [14C ]C D P choline was supplied to nodules in vivo radioactivity was found in the ER. On longer labelling periods [l4C ]phosphatidylcholine spread into denser regions o f the gradient, including the peribacteroid m embrane (which sur­ rounds the Rhizobium japonicum symbiont). [14C ]Phosphatidylcholine was a notable com ponent o f such membranes. Adenosine triphosphatase (EC 3.6.1.3) activity in the peribacteroid m em brane fraction was compared to that o f other major organelle fractions. The peribacteroid m em brane ATPase was equally active on pH 6.0 and 8.0, was stim ulated by K+ and inhibited by DES, D C C D and M o 0 4. In these respects it was more sim ilar to the ATPase activity in the ER and mitochondria than in tonoplast or cytoplasm. The results are discussed in relation to m odes o f peribacteroid m em brane biogenesis, in­ cluding enzyme modification. 
  Reference    Z. Naturforsch. 40c, 73 (1985); received July 16/Septem ber 17 1984 
  Published    1985 
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 Identifier    ZNC-1985-40c-0073 
 Volume    40 
14Author    Arkadiusz KozubekRequires cookie*
 Title    Higher Cardol Homologues (5-Alkenylresorcinols) from Rye Affect the Red Cell Membrane-Water Transport  
 Abstract    The influence o f 5-heptadecenylresorcinol and total rye 5-alkenylresorcinols isolated from rye grains on the red blood cell water perm eability was studied using osm otic shrinkage experim ents performed in 300 m M sucrose. The studied com pounds induced significant increase o f erythro­ cyte water permeability. The threshold concentration needed for the increase o f water per­ meability was in an order o f 10_ 6 m ol/l. The temperature dependence o f the observed process showed the discontinuity which was related to the 5-alkenylresorcinol transition temperatures. It was shown also that alkenylresorcinols did not exert the biphasic action on hypotonic lysis o f erythrocytes usually observed for water soluble surfactants. The sp ecific lysine activity is postulated for the studied compounds. 
  Reference    Z. Naturforsch. 40c, 80 (1985); received N ovem ber 2 1984 
  Published    1985 
  Keywords    Phenolic Lipids, 5-Alkenylresorcinols, Rye, Erythrocytes, Water Perm eability 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0080.pdf 
 Identifier    ZNC-1985-40c-0080 
 Volume    40 
15Author    Gianfranco Menestrina, Flavia PasqualiRequires cookie*
 Title    Effects of Carbohydrates on the Ion Conductance of the Hemocyanin Channel  
 Abstract    The effects o f glucose and sucrose on the ionic conductance properties o f the channel formed by Megathura crenulata hemocyanin in planar lipid bilayers have been studied using m em branes o f different compositions. It was found that glucose at high concentrations strongly affects the time constants o f the current relaxations observed in m em branes containing many channels after a step in the voltage clamp from ground to a positive value. At m uch lower concentrations both sucrose and glucose strengthened the binding o f Ba2+ to the protein, what in turn has the effect to shift the conductance voltage curve o f the pore towards negative potentials. The possible mechanism underlying these effects and the analogies with other studies on the interaction o f sugars and alcohols with proteins have been discussed. 
  Reference    Z. Naturforsch. 40c, 85—9 (1985); received October 25 1984 
  Published    1985 
  Keywords    Hemocyanin Channel, Planar Lipid Bilayer, Carbohydrates, D ivalen t Cations, Protein Conformations 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0085.pdf 
 Identifier    ZNC-1985-40c-0085 
 Volume    40 
16Author    Natalia Stoicheva, Iana Tsoneva, DimiterS. Dimitrov, Ivan PanaiotovRequires cookie*
 Title    Kinetics of Calcium-Induced Fusion of Cell-Size Liposomes with Monolayers in Solutions of Different Osmolarity  
 Abstract    The effects o f osmolarity, calcium concentration and cell-size lip osom es in the subphase on the surface tension o f phospholipid monolayers were investigated. The m onolayers were spread from chloroform solutions o f phosphatidic acid at air/w ater solution interface. The liposom es (o f average diameter 3 |im) were formed from phosphatidic a cid /e g g lecithin (1 :2) m ixtures in water or 0.1 M water solutions o f sucrose. For this system there were critical concentrations o f calcium ions to produce a large reduction o f the monolayer surface tension. The threshold calcium concentrations depended upon the sucrose concentration in the subphase. W ithout sucrose the threshold calcium concentration was 8 mM, while for isoosm otic sucrose solutions (0.1/0.1 M in /o u t o f lip osom e) it was 14 mM. It sharply increased to 28 mM CaCl2 at sucrose concentration difference across the lip osom e m em ­ brane 0.02 M and decreased to 26 mM, 19 mM, and 18 m M w ith further increase o f that difference to 0.04 m, 0.06 M, and 0.08 M, respectively. The rate o f monolayer surface tension decrease was m easured as a function o f tim e 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 m inim um occurred at sucrose concentration gradient across the lip osom e m em brane 0.02 M, i.e., at the point o f maximum threshold calcium concentration required for large decrease o f the m onolayer surface tension. These facts may be explained by recent theories o f dynam ics o f adhesion, instability and fusion o f membranes m odeled as thin films. 
  Reference    Z. Naturforsch. 40c, 92 (1985); received July 16 1984 
  Published    1985 
  Keywords    Membrane Fusion, Giant Liposomes, Phospholipid M onolayers 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0092.pdf 
 Identifier    ZNC-1985-40c-0092 
 Volume    40 
17Author    Stylianos TsakirisRequires cookie*
 Title    Control of the Activity of Brain Synaptosome-Associated Acetylcholinesterase by Acidic Phospholipids  
 Abstract    Acetylcholinesterase, Vesicles, Synaptosomal M embranes, M em brane F luidity Incubation o f synaptosomal plasma membranes (SPM) with liposom es o f phosphatidylserine (PS), phosphatidylinositol (PIN) or phosphatidylglycerol (P G L), led to an increase o f acetyl­ cholinesterase (AchE) activity at concentrations o f 0 .1 -1 (imol ph osp holip ids per mg SPM protein. The use o f higher concentrations (1 -7 (im ol/m g protein), how ever, led to a progressive inhibition o f the activity with respect to the m axim al percentage o f enzym e stim ulation. To explain the enzyme stim ulation by the acidic phospholipids, AchE was solub ilized with the detergent Lubrol-PX and showed no change in the enzym e activity at any PS, PIN or PGL concentration used, indicating that these com pounds do not act on the protein m olecule directly. Arrhenius plots o f AchE activities in untreated SPM (control), exhibited a break point at 23 °C , which was decreased to 1 6 -17 °C in PS-treated SPM. M oreover, 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 m odifications o f interactions betw een lipid and AchE may control physiological processes in the central nervous system . 
  Reference    Z. Naturforsch. 40c, 97 (1985); received August 15/Septem ber 25 1984 
  Published    1985 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0097.pdf 
 Identifier    ZNC-1985-40c-0097 
 Volume    40 
18Author    AnaR. De Boland, Ricardo BolandRequires cookie*
 Title    In Vitro Cellular Muscle Calcium Metabolism. Characterization of Effects of 1,25-Dihydroxy-Vitamin D3 and 25-Hydroxy-Vitamin D3  
 Abstract    1,25-Dihydroxy-vitamin D 3, 25-H ydroxy-vitam in Du, Cellular C alcium , M uscle Culture, Myoblasts Cultures of vitamin D-deficient chick soleus m uscle and 12 day-old chick em bryo myoblasts were used to characterize the effects o f 1,25-dihydroxy-vitam in D 3 and 25-hydroxy-vitam in D 3 on muscle cell Ca metabolism. Physiological am ounts o f both sterols increased the rate and extent o f 45Ca uptake by cultures. H owever, l,2 5 (O H)2D 3 was significantly m ore effective than 25 0 H D 3. The greater potency o f l,2 5 (O H)2D 3 to increase Ca uptake could be shown after various treatment intervals o f cultures and using a w ide concentration range o f both derivatives. Information about Ca pools affected by vitam in D 3 m etabolites was obtained through kinetic analysis o f Ca efflux in cultured myoblasts. C ytoplasm ic and m itochondria Ca pools were identified on the basis o f their half-tim es o f desaturation and by selective inhibition o f plasm a membrane and mitochondrial Ca transport with LaCl3 and R uthenium Red, respectively. The data suggests that l,25(O H)2D 3 acts on m uscle cellular Ca by increasing Ca efflux and influx through mitochondrial and plasma m embranes whereas the predom inant effect o f 25 O H D 3 is to increase Ca influx into mitochondria. 
  Reference    Z. Naturforsch. 40c, 102 (1985); received Septem ber lO /O ctober 24 1984 
  Published    1985 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0102.pdf 
 Identifier    ZNC-1985-40c-0102 
 Volume    40 
19Author    Peter Eilfeld, W. Olfhart RüdigerRequires cookie*
 Title    Absorption Spectra of Phytochrome Intermediates  
 Abstract    Native phytochrome (124kdalton) was isolated from etiolated seedlings o f Avena sativa L. cv. Pirol (Baywa, Munich). From low temperature spectra (0 ° C to — 1 6 5 °C) o f phytochrom e samples irradiated either with red or far-red light, spectra o f interm ediates were calculated. Both absorption bands o f the phytochrome chromophore were reported. On the pathway P r -i V r , native phytochrome does not form a bleached interm ediate (m eta-R b) in contrast to degraded phytochrome. An additional intermediate, meta-Rc (/ max = 725 nm), is form ed instead. On the reverse path­ way only two intermediates were found, lum i-F and m eta-F. O scillator strengths' values were calculated and interpreted in terms o f chromophore conform ation. A schem e o f interm ediates for native phytochrome is presented. 
  Reference    Z. Naturforsch. 40c, 109 (1985); received October 8 1984 
  Published    1985 
  Keywords    Avena sativa L, Native Phytochrome, Low Temperature Spectra, Chrom ophore Absorption Bands, Oscillator Strength 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0109.pdf 
 Identifier    ZNC-1985-40c-0109 
 Volume    40 
20Author    Peter Brandt, Helene Gleibs, Andrea Köhne, W. Olfgang, W. IessnerRequires cookie*
 Title    Variabilität des "light-harvesting-systems" im Zellzyklus von Chlorella fusca Variability of the Light-Harvesting-System during the Cell Cycle of Chlorella fusca  
 Abstract    The seven chlorophyll-protein com plexes CPIa, CPI, L H C P i, LHCP2, CPa, LHCP[ and LHCP]] known in part also from the chloroplasts o f higher plants were isolated from Chlorella fusca. They were characterized by their m olecular weight, their absorption m axim a and their ratio of chlorophyll a/chlorophyll b. The com position o f the chloropyhll-protein com plexes changes during the cell cycle o f Chlorella fusca. The ratio o f LH CP/C PI decreases at the beginning o f the light period and the ratio LH C P/C Pa after the 2nd hour o f the light period. Both quotients increase at the 5th hour o f the light period, have a m axim um at the 8th hour o f the light period and decrease afterwards during the second part o f the cell cycle. These altera­ tions are no reflections o f chlorophyll-accum ulation, but cause m odifications in the organization o f the thylakoids and influence the photosynthetic efficiency o f Chlorella fusca. The size o f the PSI-and PSII-units during the cell cycle was estim ated by these changes o f the LH C P/C PI-and LHCP/CPa-ratios. In addition evidence is given that the assem bly o f LHCP, and LHCP2 is no simple association o f the m onomeric forms o f LHCP] or LHCPu. 
  Reference    Z. Naturforsch. 40c, 115 (1985); received August 22 1984 
  Published    1985 
  Keywords    Thylakoid Differentiation, Chlorophyll-Protein C om plexes, Chlorella fusca, Photosystem 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0115.pdf 
 Identifier    ZNC-1985-40c-0115 
 Volume    40 
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