bluuebunny/crossref_metadata_2025 huggingface dataset:
Chalkone und Dihydrochalkone als Mehlbestandteile bei Farnen (Gattungen Cheilanthes und Notholaena ) / Chalcones and Dihydrochalcones as Constituents of Fern Farina (Genera Cheilanthes and Notholaena)
Authors: Wollenweber Eckhard
Published: August 2018

Gold-back ferns and silver-back ferns of the genus Pityrogramma are known to produce chalcones and dihydrochalcones, deposited as a farina on the under surface of their fronds. In Cheilanthes and Notholaen a mostly methy­lated flavones and flavonols are excreted, but some species are shown here to accumulate chalcones and dihydrochalcones, too. Their distribution within the genera and within the species is reported and discussed.
Phytoalexins of Hyacinth Bean (Lablab niger)
Authors: Ingham John L.
Published: August 2018

Seven isoflavonoid phytoalexins have been isolated from the fungus inoculated hypocotyls of Lablab niger and identified as the isoflavone 2′-hydroxygenistein, the isoflavanones dalbergioidin and kievitone, the pterocarpan phaseollidin and the isofiavans demethyivestitol, isovestitol and iaxifloran. Small quantities of the 2-arylbenzofuran, vignafuran, were also detected.
Protein-Catalyzed Isotopic Exchange Reaction between Cysteine and Sulfide in Spinach Leaves
Authors: Schmidt Ahlert
Published: August 2018

A protein has been isolated from spinach leaves which catalyzes the following isotopic exchange reaction: Cys-SH+H2
35S ↔ Cys-35SH + H2S . This enzyme has an pH-optimum above 9.0; its molecular weight has been estimated on a Sephadex-G-100 column to be around 64 000 daltons. During purification this exchange reaction activity follows cysteine synthase activity on DEAE-cellulose and Sephadex-G-100 column chromato­ graphy; however this enzyme fraction has not been purified to homogeneity to prove that both activities are catalyzed by the same protein.

The apparent Km for a) H2S has been determined to be 0.86 mM using cysteine as substrate and 0.6 mM using O-acetylserine as substrate; b) for cysteine was found to be 3.3 mM; and c) for O-acetylserine to be 3.3 mM. For catalysis no metal ion is required and the reaction proceeds without addition of pyridoxalphosphat. This exchange reaction might prove to be a simple method to prepare labelled cysteine from non-labelled cysteine and labelled H2S. The exchange reaction was found too in Chlorella pyrenoidosa and in Rhodospirillum rubrum.
Temperature Dependent Conformation Changes of Ribulose-1,5-bisphosphate Carboxylase Studied by the Use of 1-Anilino-8-naphthalene Sulfonate
Authors: Wildner Günter F. , Henkel Jürgen
Published: August 2018

The influence of temperature on the structure and enzyme activity of ribulose-1,5-bisphosphate carboxylase, isolated from Euglena gracilis cells, was studied. Freezing of the purified ribulose-1,5-bisphosphate carboxylase preparation causes a severe loss of enzyme activity, which can be restored again by incubation of the enzyme molecules at higher temperatures (50 °C). The titration of both enzyme samples with the fluorescence probe 1-anilino-8-naphthalene sulfonate (ANS) re­vealed an increase of the fluorescence emission of the low temperature form of the enzyme. Two different enzyme conformations can be assumed which differ in the number of binding sites for ANS and Vmax values for the carboxylase reaction but show similar binding constants for ANS and the apparent Km values for C02 .
Regulation and Characterization of L-Serine: Pyruvate Aminotransferase in Rat Liver Cytosol and Mitochondria
Authors: Hoshino Jiro , Kühne Uta , Filjak Branka , Kröger Hans
Published: August 2018

Distribution of rat liver serine: pyruvate aminotransferase between cytosol and mitochondria varies considerably with the dietary and hormonal state of animals. Feeding a high-protein diet or fasting the animals results in an increase in the enzyme activity of both fractions but more marked in the mitochondrial fraction. A low-protein diet exerts the reverse effect. A single administration of dibutyryl cyclic AMP causes a rapid elevation of the enzyme activity in both fractions, which is effectively prevented by cycloheximide, actinomycin D and cortisone. The activity in mitochondria increases with a lag of 2 h following injection of the nucleotide inducer, in contrast to the cytosol enzyme, which increases without any lag. Gel filtration and DEAE cellulose chromatography of the enzyme from both fractions revealed the similar pattern and some kinetic constants of these two types of the enzyme were not significantly different from each other. These results indicate that rat liver serine: pyruvate aminotransferase is synthesized in the extra-mitochondrial site and transfered to mitochondria.
Localization and Function of Cytochrome f in the Thylakoid Membrane
Authors: Schmid Georg H. , Radunz Alfons , Menke Wilhelm
Published: August 2018

A monospecific antiserum to cytochrome f agglutinates stroma-free swellable chloroplasts from tobacco and Antirrhinum. Consequently, antigenic determinants towards which the antiserum is directed are located in the outer surface of the thylakoid membrane. The antiserum inhibits linear photosynthetic electron transport. Just as described earlier for the antiserum to polypeptide 11000 this inhibition develops in the course of the light reaction. Ultrasonication in the presence of anti­ serum abolishes the light requirement and the maximal inhibition of the electron transport reaction is immediately observed. Electron transport in chloroplasts from a tobacco mutant which ex­ hibits only photosystem I-reactions is also inhibited by the antiserum. No time lag in the light for the onset of inhibition is observed with these chloroplasts. As chloroplasts of this mutant have only single unfolded thylakoids it appears that light might preponderantly open up partitions. If the light effect is interpreted in this way, cytochrome f should be located in the partition regions but nevertheless in the outer surface of the thylakoid membrane. However, a rearrangement of molecules in the membrane in the light by which the accessibility of cytochrome f is changed can­ not be excluded. The inhibition of linear electron transport by the antiserum is approximately 50 per cent and can only be increased to 75% upon the addition of antibodies to plastocyanin. The inhibition by the antiserum to cytochrome f as well as the combined inhibition by the antisera to cytochrome f and plastocyanin can be by-passed by DCPiP. It appears that cytochrome f and plastocyanin cannot be connected in series in the electron transport chain but are both closely associated in the thylakoid membrane.

PMS-mediated cyclic photophosphorylation in chloroplasts from wild type tobacco and the tobacco mutant NC95 is only inhibited if the chloroplasts are sonicated in the presence of anti­ serum. If one disregards, that ultrasonication might cause reaction artifacts, it is thinkable that the cytochrome f, involved in the PMS-mediated cyclic photophosphorylation reaction, might be located inside the membrane.
Elektronenmikroskopische Untersuchungen am Geruchsorgan von Ophicephalus ( Channa) obscurus GUENTHER, 1861 (Teleostei, Ophicephalidae) / Electron Microscopical Studies of Olfactory Organ of Ophicephalus (Channa) obscurus GUENTHER, 1861 (Teleostei, Ophicephalidae)
Authors: Schulte Erhard , Riehl Rüdiger
Published: August 2018

The regio olfactoria of Ophicephalus was studied by transmission electron microscopy. Two types of receptor cells were found: ciliary receptor cells and microvillous receptor cells. Both of these types represent primary sensory cells. So one can regard the light microscopical findings of Kapoor and Ojha as disproved.
Studies on the Retention of CF1 with or without Induced ATPase Activity by Pyrophosphate Treated Thylakoids and Its Relation to the Regeneration of Photophosphorylation
Authors: Schopf R. , Harnischfeger G.
Published: August 2018

The reconstitution of chloroplast coupling factor 1 (CF1) into thylakoid membranes was investigated by the fluorescence of the covalently attached label fluorescamine. In contrast to a func­tional regeneration of ATP synthesis, a rebinding of CF1 was observed regardless if the protein was in its native, purified state or had been activated for ATPase activity by heat, dithiothreitol (DTT) or trypsin treatment. The reintegration of CF1 into the thylakoid membrane was estimated to be almost quantitative.

Since the label binds covalently and irreversibly to free NH2-groups, its effects on the various functional parameters were investigated. Blocking of NH2 groups leads to inhibition of ATPase activity in isolated CF1 . Labeled factor used in a reconstitution experiment on the other hand, does still result in considerable regeneration of ATP formation.

Attaching the label to whole thylakoids leads to a differential effect on phosphorylation, which is inhibited, and the H+-uptake which seems largely unaffected. A differential effect is also observed on coupled and uncoupled electron transport.

The results are interpreted as evidence for an involvement of free NH2-groups in the mechanism of photophosphorylation.
A Method for the Purification of Large Quantities of Biologically Active Ribonucleic Acid Components from Cowpea Chlorotic Mottle Virus, a Multicomponent Plant Virus
Authors: Trim A. R. , Dawson J. R. O . , Dickerson P. E. , Sakai F. , Watts J. W. , Hirst W. , Cox R. A.
Published: August 2018

Cowpea chlorotic mottle virus RNA has been prepared in comparatively high yield (at least 50%) by a modified phenol extraction method. The preparation, which has high biological activity, has been resolved into four components by zonal centrifugation on a 15 - 40% (w/v) sucrose density gradient. The components obtained have been tested for biological activity against whole plants and plant protoplasts. Each of the two largest components RNA 1 and RNA 2 was by itself infective (50 - 90% of the specific infectivity of the whole genome) and produced virus-specific proteins (coat protein and P2) and RNAs (“RNA 3“ and “RNA 4”). Contamination by small proportions « 10 %) of neighbouring RNAs is presumed to be involved in this infectivity. The two smallest components were obtained in an almost pure form.
Changes in Gene Expression during Larval Development of Calliphora vicina Induced by Ecdysterone
Authors: Mascheck Peter , Scheller Klaus , Karlson Peter
Published: August 2018

The influence of the insect hormone ecdysterone on the composition of the RNA from the fat bodies of Calliphora larvae was investigated by hybridization experiments. DNA was iodinated in vitro with 125J. In saturation experiments, total RNA was hybridized to total DNA; under similar conditions, poly (A) RNA was hybridized to unique DNA sequences. RNA isolated from animals treated with ecdysterone exhibits a higher percentage of hybridization than a corresponding control RNA from the same developmental stage, a result even more prominent when poly (A) RNA was hybridized with unique DNA. It is concluded that ecdysterone induces the transcription of new unique DNA sequences.
The Spectral Sensitivity of the Ocelli of Calliploora (Diptera)
Authors: Kirschfeld K. , Lutz B.
Published: August 2018

The spectral sensitivity of the ocelli of Calliphora was determined by means of the electroretino-gram (ER G). Sensitivity is high in the spectral range from 340 to 450 nm ; with still increasing wavelengths it rapidly decreases. Analysis of the shape of the ERG resulting from stimuli of dif­ferent wavelengths, as well as experiments with selective chromatic adaptation, indicate that there is mainly one spectral mechanism contributing to the response.
Notizen: Isoflavonoid Phytoalexins from Leaves of Trifolium arvense
Authors: Ingham John L. , Dewick Paul M.
Published: August 2018

In response to fungal inoculation the leaves of Trifolium arvense accumulate the known isoflavonoid phytoalexins, medicarpin, maackiain, sativan, vestitol, and isovestitol. A previously undescribed isoflavan derivative (arvensan; 7,2′-dimethoxy-4′-hydroxyisoflavan) is also produced by this species. The identification and synthesis of arvensan is described.
The Orientation of the Electric Field Gradient Tensor in CO-Liganded Myoglobin
Authors: Parak F. , Thomanek U. F. , Bade D. , Wintergerst B.
Published: August 2018

The EFG-tensor at the position of the Fe-atom of CO-liganded sperm whale myoglobin has been investigated by nuclear γ-resonance absorption experiments on single crystals. In addition the tem­ perature dependence of the quadrupole splitting of the 14.4 keV level of the iron nucleus was measured. An unambiguous solution for the magnitude and the orientation of the field gradient tensor could only be obtained with the assumption that a C2-axis perpendicular to the haem plane is one principal axis of the electric field gradient tensor. Within this solution the electronic struc­ture of the iron is described by a singlet ground state with ηz = 0.75 and the largest EFG component perpendicular to the haem plane.
Conformations of the Nucleoside Analogs Formycin, 2-Azaadenosine, and Nebularine in Solution
Authors: Lüdemann H.-D. , Westhof E.
Published: August 2018

The ribose conformations of formycin, 2-azaadenosine, nebularine, 8-bromoinosine, and 8-bromo- xanthosine have been studied using proton magnetic resonance in ND3 solutions, in D2O solutions, and in pyridine solutions. The temperature was varied between - 60 °C and +40 °C in ND3 and between +10 °C and +60 °C in D2O solutions. In solution, 2-azaadenosine and nebularine have a conformational behaviour similar to that of the common purine (β) ribosides. This is in agreement with the conformations observed in the solid state. The conformations of formycin and formycin B have strong analogies with those of the 8-bromopurineribosides and differ significantly from those of the 8-azapurineribosides since they adopt preferentially the syn-S-g+ conformation. This con­formation is very probably stabilized by an intramolecular hydrogen bond between O (5′) and N (3).
Stimulation of Tyrosinase Activity and Melanin Formation of Cultured Melanoma Cells by Serum Deprivation Alone or in Combination with Dibutyryl Cyclic AMP and Theophylline
Authors: Leising H. B. , Schachtschabel D. O.
Published: August 2018

Serum removal from the media of serial monolayer cultures of the Harding-Passey melanoma during an incubation period of 3 days resulted in an exponentially declining DNA synthesis rate (measured by the incorporation of [14C] thymidine) and in an inhibition of cell proliferation. Pro­tein synthesis, as measured by the incorporation of radioactive leucine, was less affected than DNA synthesis. Incubation in serum-free culture medium resulted in significant rises of tyrosinase ac­tivity and cellular melanin content. Addition of dibutyryl adenosine 3′ :5′ monophosphate (Bu2cAMP, 5×10-4ᴍ) and theophylline (5×10-4 ᴍ) to serum-free cultures caused a further striking increase of tyrosinase activity and melanin formation, while treatment of serum containing cultures with Bu2cAMP and theophylline showed only a slight rise in melanogenesis. It is sug­gested that these stimulatory effects are mediated by an increased intracellular cAMP level, since a correlation between the degree of melanogenesis and cellular cAMP content was indicated. Treat­ment of serum-free or serum-containing cultures with the phosphodiesterase inhibitor theophylline (5×10-4 - 1×10-3 ᴍ) alone revealed only a slight enhancement (about 20%) of melanogenesis. Because augmentation of melanogenesis by serum-free medium alone or together with Bu2cAMP and theophylline was prevented by cycloheximide (or actinomycin D), de novo protein synthesis seems to be required for these stimulatory effects.
Glycerol Conformation and the Crystal Structure of Lipids. I. An Electron Diffraction Study of Tripalmitin and Conformationally Fixed Analogs
Authors: Dorset Douglas L. , Hancock Anthony J.
Published: August 2018

Transmission electron diffraction is used as a qualitative analytical probe of poly methylene chain packing in three conformationally-restricted analogs of tripalmitin derived from configurational isomers of cyclopentane-1,2,3-triol. The analysis demonstrates that the all trans “tuning-fork” conformation seen in X-ray crystal structure analyses on homologous compounds is also found in microcrystals, in contrast to a proposal by Fringeli et al. (Z. Naturforsch. 27 b, 780 [1972]) that an all cis conformation of the triglyceride exists in solvent-grown microcrystals and in multilayers. The presence of mixed polymorphs is also shown for bulk samples previously examined by X-ray powder diffraction techniques by other workers.
Comparison of Lipid Biosynthesis of Normal and Dark Kept Spinach Leaves in Photosynthetically Active Light
Authors: Heise K.-P. , Krapf G.
Published: August 2018

Upon illumination, dark starved spinach leaves show a 50% reduction of 14C-incorporation capacity into lipids. If 32P-incorporation is measured, the reduction is 85% compared to controls. The relative labelling of the fatty acid residues in total lipids of normal leaves was 80 - 90% compared to 30 - 50% in the darkened material. The kinetics of 14C-incorporation into lipids show that in the controls the majority of 14C was located in the monogalactosyl diglyceride fraction while in the dark kept material phosphatidyl glycerol and phosphatidyl choline were more highly labelled. Corresponding with the changed incorporation capacity a decrease in fatty acid concen­ tration in the glycolipid fraction and a simultaneous increase in the phosphatide fraction in dark pretreated leaves is observed. An illumination period of 30 - 60 minutes at 2×104 lx brings these inverse values back to normal. The most rapid labelling occurred in a glycolipid fraction lacking galactose and having a slightly more hydrophilic character than monogalactosyl diglyceride. The molar ratio of sugar, glycerol and fatty acids in this fraction is 1 : 1 : 1 - 2. The label in the fatty acid residues of this lipid fraction was approximately 10% in dark kept but 90% in control leaves. From 14C-incorporation behavior it is suggested that this lipid is a precursor of monogalactosyl diglyceride. The changes of the labelling pattern of lipids in leaves kept in prolonged darkness are similar to those obtained with 3-(3,4-dichlorophenyl) -1,1-dimethylurea treated Chlorella. A close connection of these effects to the decrease of photosynthetic capacity is therefore suspected. Also the observation that the concentration of α-linolenic acid, bound in the glycolipids, is reduced in dark kept material and increases upon subsequent light exposure, fits into this context. A pos­ sible explanation of these labelling shifts seems to be a pH shift in the various cell-compartments induced by light/dark treatment.
Protolytic Reactions in Photosystem II: a New Model for the Release of Protons Accompanying the Photooxidation of Water
Authors: Saphon Satham , Crofts Antony R.
Published: August 2018

Using pH indicator dye techniques we have investigated the pH changes in dark-adapted chloro- plasts following excitation by short flashes. Two types of pH indicator, cresol red and neutral red, were used, to follow the pH changes either inside or outside the thylakoids, or the net change when the membrane was made permeable to protons by uncoupling agents.

(1)With cresol red which showed the net pH changes inside and outside the thylakoids, an oscillation of the flash yield of H+ occurred with a periodicity of 4 (minima on the first and fifth flashes, the yield on the third being not significantly different from the yields on the second and fourth flashes). The pH changes did not occur in synchrony with O2-evolution.

(2)The net flash yields without addition of electron acceptor were similar to those with benzyl- viologen. The results were comparable with those obtained with the glass electrode technique by Fowler and Kok (C. F. Fowler and B. Kok, Biochim. Biophys. Acta 357, 299 - 307 [1974]).

(3)The net flash yields with ferricyanide as electron acceptor of photosystem I were higher than those in the absence of acceptor, or with benzylviologen. On the first and fifth flashes a net acidification was always observed.

(4)In the presence of 3- (3,4-dichlorphenyl) -1,1-dimethylurea (DCMU) a rapid acidification also occured on the first flash, while the pH changes induced by subsequent flashes were inhibited.

(5)The uncoupler methylamine did not inhibit the proton uptake outside the thylakoids.

(6)With neutral red as indicator for the net pH change inside and outside the thylakoids, the same oscillation of the flash yield occured as with cresol red.

(7)With neutral red in the precense of an external buffer, as a pH indicator for the internal aqueous phase alone, an oscillation of the flash yield with a periodicity of 4 also occured. The first and second flash yields were higher compared with the third than the equivalent yields of oxygen.

(8)We discuss the results with respect to a model for the release of protons in the water- splitting enzyme reactions, in which protons are not released in synchrony with O2 , but in the transitions of all the states of the watersplitting enzyme with the exception of S1 → S2 .

Our results are consistent with this model when account is taken of the release of protons inside the thylakoids with a periodicity of 2, associated with electron transfer from reduced plastoquinone.
Preparation of Human Erythrocyte Ghosts in Isotonic Solution: Haemoglobin Content and Polypeptide Composition
Authors: Saleemuddin M. , Zimmermann U. , Schneeweiß F.
Published: August 2018

Human red blood cell ghosts were prepared by dielectric breakdown of the cell membrane and subsequent electrical haemolysis in isotonic and isoionic solutions. Almost complete removal of haemoglobin (to about 0.1%) could be achieved by subjecting the erythrocytes suspended in isotonic solution to three consecutive electric field pulses of 16 kV/cm in the presence of 10 mᴍ EDTA, followed by dilution with EDTA-free isoionic medium. The cup-shaped ghost cells were electrically homogeneous. The polypeptide composition of the electrically prepared ghost cells, as analyzed by polyacrylamide electrophoresis in 1% SDS, revealed a pattern similar to ghost cells prepared by osmotic haemolysis. However, the band 6, corresponding to glyceraldehyde-3-phosphate-dehydrogenase protomer, was absent from the electrically prepared ghost cells. Also the band 8, which is eluted at low ionic strength, appeared to be very prominent in the electrical preparations.
Gibberellinaktivität verschiedener Schizaeaceen Antheridiogene im Zwergerbsentest / Gibberellin Activity of Different Antheridiogens in the Dwarf Pea Bioassay
Authors: Bürcky Klaus
Published: August 2018

The antheridiogens (native, antheridia inducing h or­ mones) of both, Anemia phyllitidis (AAn
1 and AAn
2) and Lygodium japonicum (ALy), representatives of the Schizae aceae showed similar effects to GA3 in the dwarf pea bio­ assay.
Struktur und mechanische Eigenschaften dermatosparaktischen Kollagens / Structure and Mechanical Properties of Dermatosparactic Collagen
Authors: Jonak R. , Lapière Ch. M. , Meinel A. , Nemetschek-Gansler H. , Nemetschek Th. , Riedl H.
Published: August 2018

Dermatosparactic calf-tail-tendon-collagen was investigated by mechanical measurements, electron microscopy and x-ray diffraction. We suppose, that the tensile strength decrease of the fibres is due to the irregular aggregation of subfibrils to fibrils. The x-ray diagram of the fibre is not influenced by state of disorder. Cyclic extension of dermatosparactic collagen leads to a higher increase in tensile strength than in the case of normal calf tendon. The effect might be due to the increase of fibril-and area-density resulting in an augmentation of crosslinks.
Interaction of Cibacron Dyes with Dehydrogenases and Kinases
Authors: Bornmann Lothar , Hess Benno
Published: August 2018

Cibacronblue The inhibition of the activity of various kinases and dehydrogenases by Cibacronblue 3 G-A and its structural analogues relies on the interaction of the anthrachinone moiety as well as of the neighbouring phenyl group of the dye with the proteins. Binding is intensified by hydrophobic substituents at the latter ring system.
The Reaction of Aminoacylase with Chloromethylketone Analogs of Amino Acids
Authors: Frey Jürgen , Kordel Werner , Schneider Friedhelm
Published: August 2018

1. Aminoacylase is irreversibly inactivated by the chloromethylketone analogs of benzyloxy-carbonyl-L-alanine, L-alanine, L-leucine, L-aspartic acid (β), tosyl-L-phenylalanine and L-leucyl-L-alanine. The kinetics of the inactivation of the enzyme by the halo-methylketones were investigated.

2. Leucyl-and alanyl chloromethylketone inactivate the enzyme by blocking of 4 SH groups. Experiments with [U-14C] leucyl chloromethylketone confirm that maximal 4 residues are covalently bound to the protein.

3. Inactivation of the enzyme by benzyloxycarbonylalanyl and tosylphenylalanyl chloromethyl­ ketone is the result of the substitution of the £-amino group of one lysine residue per active site and not of SH groups. However, in the presence of competitive inhibitors these halomethylketones react only with the SH groups of the enzyme, too.
Properties of Ribulose Diphosphate Carboxylase/Oxygenase in the Tobacco
Authors: Okabe Keiichiro
Published: August 2018

Photorespiration, Ribulose 1,5-diphosphate-Carboxylase/Oxygenase, Gene Composition The activity of ribulose 1,5-diphosphate (RuDP)-carboxylase and RuDP-oxygenase was measured in crude leaf extracts of the tobacco (N . tabacu m) phenotypes which differed with respect to their gene constitution and with respect to their photosynthetic and photorespiratory activity. The green wild type (JWB) which carried the discussed two nuclear factors su and aur in the condition su/su Aur/Aur and su/su Aur/aur exhibits normal photosynthetic activity and low photorespiratory activity. A yellow-green chlorophyll-deficient phenotype (Su/su) carrying Su/su Aur/Aur has high photosynthetic activity on a chlorophyll basis but also high photorespiratory activity. A new yellow phenotype (Su/su var. Aurea) carrying both nuclear factors in a heterozygous condition Su/su Aur/aur has high photosynthetic activity on the basis of chlorophyll and low photorespiratory activity. The comparison of the RuDP-carboxylase/oxygenase activity in these three phenotypes shows that in the yellow-green phenotype Su/su the affinity of the RuDP-oxygenase towards oxygen is higher than in the green phenotype JWB and in the yellow phenotype Su/su var. Aurea. The Km ((O2) values for the RuDP-oxygenase activity are 890 /um for JWB, 630 μм for Su/su and 940 μм for Su/su var. Aurea and the corresponding Ki(CO2) values are 7.4 μм for JWB, 14.9 μм for Su/su and 5.8 μм for Su/su var. Aurea at pH 8.34. On the other hand, the affinity of the carboxylating activity of the enzyme towards CO2 shows no difference between JWB and Su/su var. Aurea, but a lower affinity in Su/su. This is expressed by the K m (C 02) values which are 107 μм for JWB, 143 μм for Su/su and 96 μм for Su/su var. Aurea at pH 7.8. However, the affinity of the oxygenase function of the enzyme towards RuDP seems to be unchanged in all three tobaccos and is found to be around Km (RuDP) 27 μм. From this result it appears that the nuclear factor su decreases in the condition Su/su Aur/Aur the affinity of the RuDP-carboxylase towards CO2 and increases the affinity of the RuDP-oxygenase towards oxygen. On the other hand, the factor aur seems to suppress this gene expression in the condition Su/su Aur/aur whereas both factors do not affect the binding of RuDP onto the enzyme.
Ability to Light-Induced Conductance Change of Arthropod Visual Cell Membrane, Indirectly Depending on Membrane Potential, during Depolarization by External Potassium or Ouabain
Authors: Stieve H. , Bruns M. , Gaube H.
Published: August 2018

Light responses (ReP) and pre-stimulus membrane potential (PM P) and conductance of photoreceptors of Astacus leptodactylus and Limulus polyphemus (lateral eye) were recorded and changes were observed when the photoreceptor was depolarized by the action of external ouabain or high potassium concentration application.

1 mм/1 ouabain application causes a transient increase of PMP and ReP in Limulus, followed by a decrease which is faster for the ReP (half time 34 min) than for the PMP (half time 80 min). Irreversible loss of excitability occurs when the PM P is still ca. 40% of the reference value.

In both preparations high external potassium concentration leads to total depolarization (beyond zero line to +10 - +20mV) of the PMP and after a time lag of 10 min also to a loss of excitability (intracellular recording). In extracellular recordings (Astacus) the excitability remains at a low level of 15%. The effects are reversible and are similar whether no or 10% external sodium is present. In all experiments the light-induced changes of membrane conductance are about parallel to those of the light response.

The fact that the ability of the photosensoric membrane to undergo light-induced conductance changes is membrane potential-dependent is discussed, leading to the explanation that dipolar membrane constituents such as channel forming molecules (probably not rhodopsin) have to be ordered by the m embrane potential to keep the membrane functional for the photosensoric action.
Thioacylamide und Thioacylharnstoffderivate als Inhibitoren des Photosystem II / Thioacylamides and Thioacylureas as Inhibitors of Photosystem II
Authors: Schenk Hainfried E. A. , Hanf Jürgen
Published: August 2018

Thioacylureas and thioacylam ides were found to inhibit photosynthetic O2-evolution (Hill-reactions) of “broken chloroplasts”, some derivatives approaching an I50 of 10-5м. The inhibition site is near photosystem II. The inhibitory effects of the tested derivatives vary in their pH-dependency between pH 5 and 8.
Immobilisierung von Cytidin und Uridin über 2'.3'-O-cyclische Acetalderivate an Agarose / Im mobilisation of Cytidine and Uridine via 2',3'-O-Cyclic Acetal Derivatives to Agarose
Authors: Seela Frank , Roseineyer Helmut
Published: August 2018

Condensation of cytidine or uridine with ethyl levulinate leads to the acetals 1a/2a. The reac­tion would be expected to give mixtures of diastereoisom ers. As shown by 1H and 13C NMR spectroscopy only one diastereoisomer is formed. By spectroscopic comparison of 1a/2a with the corresponding adenosine acetal the absolute configuration of the new chiral centre was found to be R. The acetal m ethyl group of 1a/2a in exo-location can serve to distinguish the two m ethyl signals of O-2′,3′-isopropylidenecytidine and -uridine in the NM R spectra. On alkaline hydrolysis of the esters the acids 1b and 2b are formed, which can be condensed through their carboxyl groups with 6-aminohexylagarose. The affinity resins 3 and 4 contain 7.1 μmol and 7.6 μmol ligand/g moist gel respectively. A biospecificity of the new polymers to cytidine-and uridine converting enzymes is expected.
Inhibition of Mg, Ca-ATPase from E. coli by Ruthenium Red
Authors: Scherr Franz , Günther Theodor
Published: August 2018

The membrane-bound, solubilized, and trypsin-treated forms of Mg, Ca-ATPase from E. coli are inhibited by ruthenium red[R R ]. The inhibition is noncompetitive and is reduced at higher sub strate concentrations. n-Butanol-extracted ATPase is not inhibited by ruthenium red and is not activated by KCl.
The Occurrence of Phenylalanine Ammonia-Lyase and Cinnamic Acid p-Hydroxylase on the Endoplasmic Reticulum of Cell Suspension Cultures of Glycine max
Authors: Postius C. , Kindi H.
Published: August 2018

1. The time course of activity of soluble and microsomal phenylalanine ammonia-lyase (PAL) was studied in dark grown cell cultures of soybean (Glycine max). A distinct activity increase of PAL in the soluble and microsomal fraction occurred prior to the stationary phase of the cell culture. Cinnamic acid p-hydroxylase and NADH : cytochrome c reductase, too, exhibited maximal activity in the log phase, 5 days after the transfer of soybean cells to fresh culture medium.

2. Upon subfractionation of the once washed microsomal fraction by sedimentation velocity centrifugation on a sucrose gradient, membranes of the endoplasmic reticulum could be separated from fractions containing mainly membranes from the Golgi apparatus or plasma membranes, respectively. PAL and cinnamic acid p-hydroxylase were found in fractions of endoplasmic reticulum whereas no activity of either enzymes could be detected in fractions containing Golgi apparatus or plasma membranes.

3. Repeated washing of microsomal fractions led to a residual membrane-bound PAL representing about 1% of the total PAL activity of the cells. This residual membrane-bound activity could be solubilized almost completely by Triton X-100 or digitonin at concentrations of 0.5 - 5%.
Association between the Doubling Time of Various Cells and Tissues, and the SH-Content of Their Soluble Proteins
Authors: Schauenstein E. , Gölles J. , Waltersdorfer H. , Sdiaur R. J.
Published: August 2018

The num ber of SH-groups of the soluble proteins (Prot-SH) of 12 different types of animal tum ors and of cultivated chicken fibroblasts increases with decreasing doubling tim e (td). Between Prot-SH and td an inverse association was found with a significance level of 99.5%.

After 30 min incubation in vitro, 4-hydroxypentenal (HPE) reacts with different am ounts of the Prot-SH of the investigated cells and tissues. It was found that the absolute, as well as the per­ cental amounts of HPE-reactive Prot-SH increase with decreasing td, each of the respective inverse associations was found to be highly significant. The tum ors were collected in three groups, each with a corresponding range of td and a mean value for Prot-SH . Taking the Prot-SH of the slowest growing tissue (DENA-hepatoma) as the reference value, the increments of Prot-SH were cal­ culated for each of the three groups and were found to be strikingly similar to the number of HPE-reactive Prot-SH. The single Prot-SH increm ents of the diverse cell and tissue types compared with DENA-hepatoma were found to be highly significantly and inversely associated with the respective Prot-SH decreases caused by HPE.

Hence it may be concluded that HPE reacts preferably with those of the Prot-SH which are of some functional importance for tum or growth and, moreover that the attack on those thiols is the more effective the faster the tumor is growing.
Uptake of Polynucleotides by Mammalian Cells XV. Properties and Function of a DNA-Protein Complex Situated in the Outer Membrane of Ehrlich Ascites Tumor Cells
Authors: Schell P. L.
Published: August 2018

1) DNA-protein complexes are supposed to be original constituents of the membrane of Ehrlich ascites tum or cells. These complexes can be attacked at the surface of viable cells by DNase or protease. The DNA is partially embedded in protein structures.

2) The net charge of this complex is of major importance for the RNA uptake capacity of the cells. Negatively charged DNA which is situated at the surface hinders RNA uptake. This is the explanation for the stimulation of RNA uptake by DNase or the decrease in RNA uptake after protease treatment.

3) Upon treatment of DNA-dcficient complexes with homologous or heterologous DNA the original RNA uptake capacity of the cells is restored but the original conformation of the complex cannot be regained.

4) The DNase action on the complex is tem perature dependent in a sigmoidal fashion. It is m arkedly slowed down at tem peratures below 12 °C. This implies that structural dianges in the complex occur at this transition tem perature which make surface DNA susceptible to DNase. This effect can only be observed in original structures but not in reconstituted ones.

5) Polyanion treatment of the cells [poly (L-lysine) ] which increases their RNA uptake capacity, most probably does not interact with the DNA-protein complex. Poly (L-lysine) appears to act at other m em brane sites.

6) The DNA-protein complex has been investigated entirely in situ , i. e. situated in the membrane of viable cells.
Zur Photosynthese grüner Pflanzen, VIII [1]: in vitro-Sauerstoffaustausch zwischen Carotinoid-Epoxiden und Wasser? / Photosynthesis of Green Plants, V III: in vitro Oxygen Exchange between Carotenoid Epoxides and Water? 1
Authors: Johannes B. , Budzikiewicz H.
Published: August 2018

The in vitro exchange between the epoxide oxygen of carotenoids and that of water reported in literature could not be verified. Our observations rather suggest that oxidation products of the labile polyene system may invalidate 18O enrichment data obtained by indirect analysis.
Properties of Single Cells in Posterior Lateral Eyes of Jumping Spiders
Authors: Hardie R. C. , Duelli P.
Published: August 2018

Properties of single cells in the posterior lateral (PL) eyes of the jum ping spider Plexippus validus are described. Only one spectral class of cells was encountered and the spectra sensitivity was indistinguishable from that measured from the ERG , both peaking at ca. 535 nm. Angular sensi­ tivity (width of angular sensitivity function at the 50% level) averaged .89° ± .12°, the smallest value being .77°. Absolute sensitivity (reciprocal of the number of quanta of peak wavelength, on axis required to generate a 50% response) averaged 1.43 + 2 .5 X 1 0 -11 q-1 ,cm2·s. A ll cells studied were sensitive to the plane of polarised light. The per­ formance of receptors in the PL eyes is compared with that of receptors in the compound eyes of diurnal insects. It is concluded that the single lens eye system of spiders is in ­ herently superior in design to the insect compound eye.
Characterization, Development and Localization of "Flavanone Synthase" in Tulip Anthers
Authors: Siitfeld R. , Kehrel B. , Wiermann R.
Published: August 2018

1. “Flavanone synthase” was isolated from anthers of Tulipa cv. “Apeldoorn” and partially purified by (NH4) 2SO4 fractionation, gel chromatography and isoelectric focussing. The enzyme preparation was free of chalcone-flavanone isomerase activity.

2. p-Coumaroyl-CoA, caffeoyl-CoA and feruloyl-CoA were found to be efficient substrates of the synthase. The products formed were naringenin (5,7,4′-trihydroxyflavanone), eriodictyol (5,7,3′,4′-tetrahydroxyflavanone) and homoeriodictyol (5,7,4′-trihydroxy-3′-methoxyflavanone), respectively. Addition of thiol reagents at concentrations exceeding 10-3 м caused inhibition of the enzyme. “ Release products” , however, were not detectable. Although exclusively chalcones accumulate in the tulip anther, only flavanones but no chalcones were detectable in our in vitro system.

3. The apparent Km values for p-coumaroyl-CoA, caffeoyl-CoA and feruloyl-CoA were 1 .7× 10-6 м, 1.6× 10-6 м and 2 .5 ×10-6 м, respectively. Similar data were observed for malonyl- CoA.

4. No cofactors are required for the synthase reaction. The enzyme is strongly inhibited by the reaction products flavanone and coenzyme A . Maximum enzyme activity was found at pH 8.0 and 30 °. The molecular weight was approx. 55,000.

5. Synthase activity develops in early postmeiotic stages of microsporogenesis. Highest specific activities of the enzyme coincide with a maximum in chalcone accumulation within the anthers.

6. The contents of anthers was separated into two fractions, pollen and tapetum. Highest specific activities were observed with tapetum fractions, while pollen fractions exhibited only very low activities. The high enzyme activity in the tapetum fraction points to the important role of the tapetum in the biosynthesis of flavonoids in the loculus of anthers.
Differentiation of Rhizobium japonicum, III. Inhibition of Nitrogenase Derepression by Chloramphenicol and Rifampicin Concentrations, Not Inhibiting Growth
Authors: Werner D.
Published: August 2018

Development of nitrogenase (40 -140 nmol C2 H4 · mg protein-1· h-1) in Rhizobium japonicum 61-A-101 after transfer to special culture conditions (medium 20 P, 2% O2, 10% CO2, 88% N2 in the gas phase) is inhibited by chloramphenicol (6X 10-4 ·1O-3 м) and by rifampicin (10-5м). These concentrations do not inhibit the slow growth of the cells under these conditions with a doubling time of the cell protein and living cell number of 3 - 5 d. Nitrogenase activity of previously derepressed cells is not inhibited by chloramphenicol. Growth of the cells under air in yeast extract-mannitol-glycerol medium (8 h doubling time) is affected significantly more by chloram­phenicol (2.5 · 10-4 м) than growth under nitrogenase derepressed culture conditions.
Structural Aspects of Histone Complexes and Nucleosomes Revealed by the Accessibility of Cysteine Side Chains
Authors: Bode Jürgen , Standt Ulrich-Dieter
Published: August 2018

Chemical modification with 5,5′-dithiobis-(2-nitrobenzoic acid) shows that histone H3 cysteines 110 (chicken) or 96 and 110 (calf) are completely protected in native chromatin and core particles but become unmasked simultaneously during a salt induced dissociation. In whole histone extracted from chicken erythrocyte chromatin, H3 Cys-110 residues experience a uniform environ­ment at 2 м NaCl and pH 5.5. In whole histone extracted under the same conditions from calf thymus, H3 Cys-96 provides a more accessible thiol group than Cys-110. At higher pH values a conformational heterogeneity is induced causing a partial exposure of both cysteine side chains. The kinetic approach described in the present work provides a highly sensitive means to probe the homogeneity of H3 containing protein complexes
Mode of Binding of Pyridoxal Phosphate to 5-Aminolevulinate Synthase
Authors: Nandi Dhirendra L.
Published: August 2018

5-Aminolevulinate synthase of Khodopseudomonas spheroides interacts with its cofactor, pyridoxal phosphate, and shows an absorption maximum at 430 nm with a probable shoulder at 320 -330 nm. The enzyme-PLP complex absorb­ing at 430 nm is the predominant species at pH 7.2 and can be reduced by NaBH4 at neutral pH with a spectral shift of the absorption maximum to 325 nm. These data suggests the formation of a Schiff base rather than a substituted aldimine between the enzyme and pyridoxal phosphate. The decrease in absorption at 430 nm and increase in absorption at 325 nm by the addition of 2-mercaptoethanol seem to sup­port Schiff base structures for the absorption bands at 430 nm and 320 -330 nm. Both pyridoxal phosphate and glycine can equally protect the enzyme from inactivation by sulfhydryl reagents. The inhibition by p-chloromercuribenzo- ate versus PLP and glycine is noncompetitive and that by N-ethylmaleimide is noncompetitive with glycine and compet­itive with PLP. These results suggest either a conformational change in the presence of substrates or loss of affinity by the enzyme for PLP, rather than an interaction of PLP with a -SH group of the enzyme. The combined data seems to eliminate the possibility of the formation of a thiohemiacetal or a substituted aldimine and support rather strongly the formation of a Schiff base between the enzyme and pyridoxal phosphate.
Uracil Catabolism by Escherichia coli K12S
Authors: Šimaga Š. , Kos E.
Published: August 2018

Experiments designed to elucidate the mechanism of uracil degradation by E. coli K12S showed that in contrast to uracil, dihydrouracil - the postulated intermediate of a reductive mechanism - did not stimulate the growth of bacteria as additional source of nitrogen, nor it was catabolized to ureido carbon dioxide. However, the chromatographic analysis of dihydrouracil metabolic products, re­vealed the presence of an enzyme converting dihydrouracil to β-ureidopropionic acid. Results of growth and biochemi­ cal studies indicated that barbituric acid - the postulated intermediate of an oxidative pathway - is not involved in uracil degradation.
Ferredoxin Catalyzed Cyclic Photophosphorylation: Reversal of Dibromothymoquinone Inhibition by N ,N ,N′,N′-Tetramethyl-p-phenylenediamine
Authors: Binder R. G. , Selman B. R.
Published: August 2018

Conditions for washed, spinach thylakoid membranes to catalyze cyclic phosphorylation using ferredoxin as the cofactor for electron transfer have been re-examined. It was found necessary to “redox poise” the system; however, the best method to accomplish the poising seemed to be the use of a reductant (glucose-6-phosphate) and not by optimizing the rate of phosphorylation with 3- (3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU). Under these conditions, ferredoxin catalyzed cyclic phosphorylation was found to be sensitive to the inhibitors antimycin A and dibromothymo- quinone (DBMIB). The inhibition of ferredoxin catalyzed cyclic phosphorylation by DBMIB, but not by antimycin A, was completely reversed by N, N, N′ N′-tetramethyl-p-phcnylenediamine (TMPD). These data are taken as further support for the function of plastoquinone in ferredoxin catalyzed cyclic phosphorylation. The effect of TMPD in reversing the DBMIB inhibition is inter­preted as the formation of a TMPD bypass on the internal side of the thylakoid membrane around the DBMIB site of inhibition.
Analysis of Different Mechanisms of Photosynthetic Oxygen Reduction
Authors: Elstner E. F. , Frommeyer D.
Published: August 2018

Three mechanisms of oxygen reduction by chloroplast lamellae in the presence of autoxidizable electron acceptors can be differentiated by product analyis in the presence or absence of either dibromothymoquinone (DBMIB) or superoxide dismutase (SOD) :

1)H2O2 is the product of two-electron oxygen reduction by 2,3-dimethyl-5,6-methylencdioxy-p- benzoquinone, involving only photosystem II. This reaction is not inhibited bv either DBMIB or SOD.

2)Superoxide anion, and H2O2 as the product of its dismutation, are products of monovalent oxygen reduction following autoxidation of certain low potential electron acceptors (herbicides) of photosystem I. These reactions are not inhibited by SOD but are blocked by DBMIB.

3)H2O2 is the product of and “apparent” two-electron photoreduction of oxygen, mediated by certain o-diphenols (caffeic acid). These reactions are inhibited by both DBMIB and SOD in­dicating the involvement of photosystem I and of O2- as an intermediate in the H2O2 producing reaction.
Über den Gehalt an membrangebundenen und freien Ribosomen in Saccharomyceszellen nach Hemmung der Proteinsynthese mit Cycloheximid / The Content of Membrane-Bound and Free Ribosomes in Saccharomyces after the Inhibition of Protein Synthesis with Cycloheximid
Authors: Kraft-Creech Joan , Pietsch Ingrid , Lochmann Ernst-Randolf
Published: August 2018

After the inhibition of protein synthesis in Saccharomyces cells with cycloheximid, the content of membrane-bound ribosomes decreases significantly, whereas the content of free ribosomes remains the same as the untreated control for a longer period of time. This is further evidence that in yeast cells protein synthesis takes place only on membrane-bound ribosomes.
Anthocyanins Isolated from Petals of Various Genotypes of the Red Campion (Silene dioica (L.) Clairv.)
Authors: Kamsteeg John , Brederode Jan van , Küppers Frans J. E. M. , Nigtevecht Gerrit van
Published: August 2018

Anthocyanin pigments present in petals of various genotypes of Silene dioica were identified by RF-values, UV-spectra, partial and total hydrolysis, alkalysis, NMR-and IR-spectra. Both the 3-glucosides, 3,5-diglucosides, 3-rutinosides and 3-rutinosides-5-glucosides of cyanidin and pelargonidin were found.

The location of the acyl group at the 3-O-bound sugar in acylated anthocyanins - p-coumaric acid in pelargonidin-glycosides and caffeic acid in cyanidin-glycosides - has been determined by partial hydrolysis, peroxide oxidation, and oxidative cleavage with sodium periodate followed by reduction with sodium borohydride and identification of the polyalcohols formed after hydrolysis. The phenolic acids have been shown to be attached to the 4-hydroxyl group of rhamnose in anthocyanidin 3-rhamnosylglucosides and to the 6-hydroxyl group of the 3-O -bound glucose in anthocyanidin 3-O-glucosides.