bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Persisting Chromosome Aberrations by Flow Karyotyping of Cloned Chinese Hamster Cells
Authors: Otto Friedrich J.
Published: August 2018

A preparation, staining and measuring protocol for high resolution flow cytometry of chromosomes was developed. This method allows us to identify all chromosome types and is suited for characterization of permanent cell lines and cell clones by establishing their flow karyotypes. In cell clones this procedure can be used for the detection of chromosomal aberrations which appear spontaneously or are induced by mutagen treatment and persist in the cell population.
The Position of Carotene in the D-1/D-2 Sub-Core Complex of Photosystem II
Authors: Brody S. S.
Published: August 2018

When the sub-core complex of photosystem II, D1/D2, is irradiated at 436 or 415 nm (absorption by chlorophyll and pheophytin and β-carotene) or 540 nm (absorption primarily by pheophytin), the low temperature fluorescence spectrum has two maxima, at 685 and 674 nm. This shows the existence of at least two different fluorescent forms of chlorophyll (chlorophyll a and perhaps pheophytin a). When carotene is irradiated at 485 nm (absorption primarily by β-carotene), only fluorescence at 685 nm is observed: this indicates that carotene is transferring energy to only the long-wavelength form of chlorophyll in the D1/D2 sub-core complex. The band of carotene (at 485 nm) does not appear in the fluorescence excitation spectrum, measured at 674 nm. The position of the carotene molecule relative to each of the fluorescent forms of chlorophyll was determined from the excitation spectra of each of the fluorescence bands.
Interaction of Testosterone and Testosterone Receptor Complexes with Nuclei of Skeletal Muscle from Intact Male Mice and from Mice Bearing the Testicular Feminization (Tfm) Mutant Gene
Authors: Franzelius Cornelia , Eisele Karl
Published: August 2018

With the nuclear exchange assay and the nuclear retention assay it is shown that the androgen insensitivity of Tfm mice is probably due to a defect of the nuclear acceptor sites for the testosterone receptor complex. Furtheron the results obtained point strongly to the possibility that hormone free androgen receptor is localized in the nuclei and in the cytoplasma according to the “equilibrium model”. A practicable method for separation of unbound steroids from nuclei is described.
The Effects of the Herbicide Sethoxydim on Transport Processes in Sensitive and Tolerant Grass Species II. Effects on Membrane-Bound Redox Systems in Plant Cells
Authors: Weber Angela , Lüttge Ulrich
Published: August 2018

Leaf slices of sethoxydim-sensitive (Poa pratensis, Festuca ovina) and tolerant (Poa annua, Festuca rubra) grass species were found to be able to reduce extracellular ferricyanide by electron transport across the plasmalemma. This reduction was inhibited by the herbicide sethoxydim, and the sensitive species were much more strongly affected than the tolerant ones. The inhibition was concentration dependent. Sethoxydim affected the electron transport in isolated Poo chloroplasts. Polarographic and photometric measurements of ferricyanide reduction suggested photosystem II to be the site of action. Inhibition occurred only in the sensitive species Poa pratensis and was linearly dependent on concentration. In isolated mitochondria from sensitive Zea mays coleoptiles sethoxydim also acted as an inhibitor of electron transport. Only slight inhibition was measured with mitochondria from tubers of tolerant potato (Solanum tuberosum).

It is concluded that sethoxydim generally acts as inhibitor of membrane-bound redox systems. The specific inhibition of the plasmalemma-bound redox system of sethoxydim-sensitive plants could contribute to a selective action of the herbicide.
Composition of Propolis in Oxfordshire, U.K. and its Relation to Poplar Bud Exudate
Authors: Greenaway W. , Scaysbrook T. , Whatley F. R.
Published: August 2018

Propolis balsam from four locations in Oxfordshire was analysed. The balsam was qualitatively similar but showed large quantitative differences in composition. These quantitative differences are related to the bud exudate composition of the poplars from which balsam was gathered.
How Different are the Crystal Structures of Chiral and Racemic Diacylphosphatidylethanolamines?
Authors: Dorset Douglas L.
Published: August 2018

Both chiral and racemic phosphatidylethanolamines are known to crystallize in a similar polymorphic form with nearly the same lamellar spacing; yet published lamellar X-ray diffraction intensity data for those materials do not agree with one another, even though the peak positions in Patterson maps are nearly the same. Translational structural searches based on the crystal structure of the racemic compound also lead to similar packing models with both data sets, although the agreement between model and observed data is poor for the chiral compound. A separate analysis of ʟ-DMPE based on lamellar electron diffraction data again leads to a similar lamellar structure with a better agreement between calculated and observed structure factors. The major difference seen for enantiomeric vs. racemic compounds is that, for the racemic lipid, the lateral unit cell spacings are about 3% larger than the chiral form, perhaps indicating a more stable hydrogen bonding network, in agreement with the higher melting point of the racemic compound. Attempts to explain this difference with other head group conformations, however, have not yet produced an improved structural model.
Lipid Composition of Photosystem I and II in the Tobacco Mutant Nicotiana tabacum NC 95
Authors: Bednarz J. , Radunz A. , Schmid G. H.
Published: August 2018

The lipids of photosystem II particles, of chloroplasts and leaves are compared in the variegated tobacco mutant NC 95. The mutant differs from other N. tabacum mutants by the phenomenon that it has variegated leaves with green and with yellow-green leaf patches. Chloroplasts from the green leaf areas exhibit photosystem II and photosystem I reactions and have a normal lamellar system with grana and intergrana regions. Chloroplasts from the yellow-green leaf areas, however, yield only photosystem I reactions and have only single stranded isolated thylakoids. Hence, this mutant offers the unique possibility to compare without the use of detergents within the same plant the lipid composition of photosystem II particles with that in intact chloroplasts, exhibiting either photosystem II and I reactions or those exhibiting exclusively photosystem I reactions.

The lipids of photosystem II particles are composed of 37 % glycolipids, 4 % phospholipids, 5 % carotenoids and 54 % chlorophyll. Lipids of chloroplasts with grana stacking are composed of 75% glycolipids, 7 % phospholipids, 2 % carotenoids and 16% chlorophyll. Chloroplasts with single isolated thylakoids have a lipid composition consisting of 8 3 % glycolipids, 14% phospholipids and only 0.5% carotenoids and 2 % chlorophyll. The chloroplast lipid mixture is characterized in comparison to the respective leaf lipid mixture by a 16-17% higher glycolipid portion and by a 13-70% lower phospholipid content.

The main difference in the lipid composition of photosystem I and II consists in the observation that chloroplasts active in only photosystem I contain more than double the amount of glycolipids and the 4-fold amount of phospholipids in comparison to photosystem II active preparations. The amount of monogalactolipid is even 3 times higher in chloroplasts active only in photosystem I when compared to those in photosystem II particles. In photosystem II particles phosphatidylethanolamine is completely lacking and phosphatidylglycerol and phosphatidylinositol occur only in traces.

The fatty acids of the sulfolipid are by 45 % more saturated in the photosystem II particles and the digalactolipids of the photosystem II particles are by 28 % more saturated than in chloroplasts exhibiting photosystem I and II activity.
Field Tests with Sex Attractants of Diachrysia chrysitis and D. tutti (Lepidoptera: Noctuidae) at Several Sites in Hungary
Authors: Tóth M. , Szőcs G. , Molnár J. , Szarukán I.
Published: August 2018

Sex attractants for the sibling taxa Diachrysia chrysitis (L.) s.str. and D. tutti (Kost.) were field tested on 9 sites in Hungary. Catches with the two already described attractant blends, Z-5-10:Ac/Z-7-10:Ac in ratios 10:1 and 2:100, were similar to earlier results obtained in areas more to the west, chrysitis s.str. type males responding to the 10:1 while tutti type males to the 2:100 ratio. Substantial chrysitis s.str. catches were also obtained by the intermediate 1:1 blend. On all 9 sites the two taxa were co-occurring.
Synthesis of Two Allergenic Constituents of Propolis and Poplar Bud Excretion
Authors: Hashimoto T. , Tori M. , Asakawa Y. , Wollenweber E.
Published: August 2018

The prenyl ester and the phenylethyl ester of caffeic acid, formed in the bud excretion of poplar species, were shown recently to be the major contact allergens in bee-glue. A n unambiguous synthesis of these compounds, based on the reaction of caffeic acid with 1-bromo-3-methyl-2-butene and with β-bromoethylbenzene, respectively, is reported. The synthetic products confirm the previously described structures of the natural products and allow further testing of their allergenic properties.
3-Hydroxy Retinal, a New Chromophore Identified in Insect Eyes: HPLC Separation and NMR Spectroscopic Identification of the Oxime Forms
Authors: Gärtner Wolfgang , Plangger Anette
Published: August 2018

3-Hydroxy retinal acts as visual chromophore instead of retinal in the eyes of several insect orders. A HPLC separation system of the aldehyde and oxime isomers and their identification by 400 MHz 1H NMR spectroscopy is described.
Demonstrating Evolutionary Relationships Between Macromolecular Sequences through Mutual Relationships with a Third Sequence
Authors: Staves Mark P. , Bloch David P. , Lacey James C.
Published: August 2018

Corresponding sites of the Euglena chloroplast and yeast small subunit ribosomal RNAs (rRNAs) show only an insignificant match with each other but show extensive matches with the Euglena chloroplast tRNAarg. The match with the tRNA extends farther toward the 5′ end of the Euglena rRNA and toward the 3′ end of the yeast rRNA. The expected number of such configurations given the number of RNAs searched is about 1 in 100,000. Comparison of two sequences with a third sequence frequently reveals relationships where pairwise comparisons fail to do so.
Immunochemical Comparative Study on RuBP Carboxylase/Oxygenase of Different Tobacco Mutants Exhibiting Different Levels of Photorespiration
Authors: Radunz A. , Schmid G. H.
Published: August 2018

By means of the immunochemical methods of double immuno diffusion and tandem crossed immuno electrophoresis we have compared the bifunctional enzyme RuBP carboxylase/oxygenase from tobacco mutants which differ with respect to their rates of photosynthesis and photorespiration. The comparative studies were carried out with a monospecific antiserum to the enzyme of the wild type Nicotiana tabacum var. John William’s Broadleaf. RuBP carboxylase/oxygenase from the green, yellow-green and yellow phenotype of the mutants namely N. tabacum Su/su, N. tabacum Su/su var. Aurea, N. tabacum var. Consolation, N. tabacum var. NC 95 and N. tabacum Xanthi (D 523) are immunochemical^ identical to the enzyme of the wild type N. tabacum var. John William’s Broadleaf. Furthermore, immunochemical identity of the RuBP carboxylase/oxygenase exists between Nicotiana tabacum and other representatives of the Solanaceae such as Solanum tuberosum, S. lycopersicum and Datura suaveolens. In contrast to this only partial identity to the enzymes of the C3-plants Antirrhinum majus, Spinacia oleracea, Sinapsis alba, Petroselinum crispum, Allium porrum, Hordeum vulgare, Avena sativa to the enzymes of the green alga Chlorella vulgaris and to the blue-green alga Oscillatoria chalybea as well as to the enzyme of the C4-plant Zea mays is observed.
Metabolism of Ferulic Acid Sucrose Esters in Anthers of Tulipa cv. Apeldoorn: II. Highly Specific Degradation of the Esters by Different Esterase Activities
Authors: Bäumker P. A. , Arendt S. , Wiermann R.
Published: August 2018

Protein extracts from anthers of Tulipa cv. Apeldoorn catalyze the degradation of ferulic acid sucrose esters. Different products are generated when triferuloyl sucrose (TFS) and diferuloyl sucrose (DFS) were applied as substrates. By the aid of reversed-phase HPLC , TLC and spectroscopy the products could be identified as free ferulic acid, monoferuloyl sucrose ester [feruloylsucrose(mono)] and two different diesters of ferulic acid and sucrose [feruloylsucrose(di) and the endogenously occurring diferuloylsucrose (DFS)]. By means of protein fractionation (chromatofocusing, anion exchange HPLC and molecular sieving HPLC) , four different enzyme activities involved in the degradation process could be separated. According to their catalytic properties, they were characterized as esterases (= EA).

The partially purified esterase activity I (EAI) obtained after fractionation by chromatofocusing catalyzes the formation of feruloylsucrose(di) and ferulic acid when TFS is used as substrate. Incubations with EA la or EA Ib isolated in smaller portions lead to the same product pattern.

The esterase activity II (EA II) degrades TFS to ferulic acid and DFS . DFS as substrate is only accepted by the EA I activities, in all three cases ferulic acid and feruloyl sucrose(mono) are formed as products. The kinds of different degradation reactions clearly indicate that one enzyme (= the EA II activity) catalyzes exclusively the formation of DFS from TFS.

Both enzymes, EA I and EA II, exhibit a high specificity towards ferulic acid sucrose esters. Hydroxycinnamic sucrose esters with only sinapic acid moieties do not function as substrates. When enzymatically formed sucrose esters like feruloylsucrose(di), feruloylsucrose(mono) and monosinapoylsucrose were used as substrates, no product formation could be observed. Applying SFS as substrate, only the ferulic acid moiety was released by EA I. Further, naturally occurring esters (glucose- and CoA-esters of p-coumaric, caffeic, ferulic and sinapic acid; chlorogenic acid; BGM ) tested so far were not degraded by EA I and EA II. It is assumed that these esterase activities play a specific role in the ferulic acid metabolism in Tulipa anthers.
Accumulation of Protoporphyrin IX in the Presence of Peroxidizing Herbicides
Authors: Sandmann Gerhard , Böger Peter
Published: August 2018

Peroxidizing herbicides were assayed for their capacity to accumulate tetrapyrrole-like compounds in the liquid culture medium when growing the xanthophycean alga Bumilleriopsis filiformis. We have isolated and purified this compound by HPLC . For identification optical, fluorescence, NMR and mass spectroscopy were employed. All these techniques showed that the accumulation product is protoporphyrin IX. This tetrapyrrole was found, although to a different extent, using either chlorophthalim, oxadiazon, oxyfluorfen or LS 82-556. Accumulation of protoporphyrin IX caused by peroxidizing compounds was also found in light-grown Bumilleriopsis cells and heterotrophically (dark-)grown Scenedesmus cells, but neither in light-grown Scenedesmus cells nor in dark-grown Neurospora.
Characterization of Two Soluble Basic Cytochromes Isolated from the Anoxygenic Phototrophic Sulfur Bacterium Chlorobium phaeobacteroides
Authors: Fischer Ulrich
Published: August 2018

Chlorobium phaeobacteroides contains two soluble basic c-type cytochromes, a flavocytochrome c-552 and a small cytochrome c-555. Both electron transfer proteins were highly purified by ion exchange chromatography and gel filtration.

The flavocytochrome c-552 exhibits maxima at 552 nm, 523 nm and 416 nm in the reduced state and at 409.5 nm with two shoulders at 440 nm and 480 nm in the oxidized form. The best purity index (A280/A416)obtained was 0.65. The molecular properties of this flavocytochrome are as follows: isoelectric point, pH 9.5 - 10; redox potential, +63 mV; molecular weight, 56,000.

Cytochrome c-555 is a small basic hemoprotein with an isoelectric point of pH 9.5 - 10, a molecular weight of 9,500 and a midpoint redox potential of +105 mV. The best purity index {A280/A418) obtained was 0.176. The oxidized form of this cytochrome has a maximum at 411.5 nm, while the reduced state shows three maxima (α-band at 554.5 nm; β-band at 523 nm, and γ-band at 418 nm). The a-band is asymmetrical with a typical shoulder at 551 nm.
Different Porphobilinogenases in Cytoplasm and Isolated Chloroplasts from Light-Grown Euglena gracilis Z.
Authors: Juknat A. A. , Dörnemann D. , Senger H.
Published: August 2018

Lysed cells as well as different fractions of isolated, disrupted chloroplasts from light grown Euglena gracilis were tested for their capability of porphyrin biosynthesis. It is shown that the formation of the soluble porphobilinogenase (PBG-ase) fraction is inhibited by cycloheximide indicating its biosyntheses on 80S ribosomes, whereas the formation of the membrane bound chloroplast PBG-ase is chloramphenicol sensitive. Different pH-optima are demonstrated for the two enzymes. From the presented results it is deduced from those isolated from dark grown cells.
Acclimation of the Photosynthetic Apparatus to Photosystem I or Photosystem II Light: Evidence from Quantum Yield Measurements and Fluorescence Spectroscopy of Cyanobacterial Cells
Authors: Melis Anastasios , Mullineaux Conrad W. , Allen John F.
Published: August 2018

Cells of the cyanobacterium Synechococcus 6301 were grown under illumination whose spectral composition favoured absorption either by the phycobilisome (PBS) light-harvesting antenna of photosystem II (PS II) or by the chlorophyll (Chi) a light-harvesting antenna of photosystem I (PS I). Cells grown under PS I-light developed relatively high PS II/PS I and PBS/Chl ratios. Cells grown under PS II-light developed relatively low PS II/PS I and PBS/Chl ratios. Thus, the primary difference between cells in the two acclimation states appeared to be the relative concentration of PBS-PS II and PS I complexes in the thylakoid membrane. Measurements of the quantum yield of oxygen evolution suggested a higher efficiency of cellular photosynthesis upon the adjustment of photosystem stoichiometry to a specific light condition. The quantum yield of oxygen evolution was nevertheless lower under PBS than Chi excitation, suggesting quenching of excitation energy in the photochemical apparatus of PS II in Synechococcus 6301. This phenomenon was more pronounced in the PS II-light than in the PS I-light grown cells. Room temperature and 77 K fluorescence emission spectroscopy indicated that excess excitation energy in the PBS was not transferred to PS I, suggesting the operation of a non-radiative and non-photochemical decay of excitation energy at the PBS-PS II complex. This non-photochemical quenching was specific to conditions where excitation of PS II occurred in excess of its capacity for useful photochemistry.
HPLC-Determination of Apomorphine in a Mormyrid Fish, Gnathonemus petersii
Authors: Noe Angela , Kunze Peter
Published: August 2018

Uptake of apomorphine and elimination kinetics in brain and muscle tissue of the weakly electric fish Gnathonemus petersii (Mormyridae) was determined by HPLC. 20 min exposure of the fish to apomorphine in the aquarium water (0.4 mg/1) resulted in a concentration factor of 1.09 for brain and 0.55 for muscle tissue. Elimination from brain tissue can be described with first order kinetics (t1/2 = 2.4 h).
Modulation of Millisecond Chlorophyll Luminescence by Non-Photochemical Fluorescence Quenching
Authors: Bilger W. , Schreiber U.
Published: August 2018

By combining a high frequency modulation system for measurement of fluorescence with a phosphoroscope type apparatus for measurement of luminescence, recordings of fluorescence and luminescence induction kinetics under identical conditions were obtained. Both measuring sys­tems tolerated the application of saturating pulses of white light for rapid, transient elimination of photochemical quenching at photosystem II reaction centers, thus allowing determination of the non-photochemical quenching component. The saturation pulse induction curves of luminescence are well correlated with the corresponding curves of fluorescence, suggesting that luminescence yield is lowered by the same type of non-photochemical quenching (mostly “energy dependent quenching”) as fluorescence. Hence, in order to evaluate luminescence signals in terms of the rate of charge recombination at photosystem II reaction centers, knowledge of fluorescence quenching is required.
Immunological Identification of Polypeptides in Photosystem II Complexes from the Cyanobacterium Anacystis nidulans
Authors: Gau Achim E. , Wälzlein Gudrun , Gärtner Susanne , Kuhlmann Matthias , Specht Susanne , Pistorius Elfriede K.
Published: August 2018

Photosystem II complexes from the cyanobacterium Anacystis nidulans have been investigated by Western blots with antisera raised against four photosystem II peptides from plants and with an antiserum raised against the soluble L-amino acid oxidase protein from/1. nidulans to achieve an iden­tification of the polypeptides - especially of the L-amino acid oxidase related protein - in isolated photosystem II complexes. Anacystis photosystem II complexes which were solubilized with lauryldimethylamine N-oxide and purified by sucrose cushion and sucrose gradient centrifugation, contained as major Coomassie brilliant blue stained polypeptides a 71 kDa band of unknown identity, a 62 kDa band, which partly contained D-l, a 55 and 49 kDa band which were immuno-reactive with an antiserum to the 47 kDa peptide of tobacco PS II complexes, and three distinct bands in the 30 kDa region. These latter bands could be identified as the extrinsic Mn stabilizing peptide (27-30 kDa), D-l (30-33 kDa) and a 36 kDa peptide (35 - 38 kDa) which crossreacted with the antiserum raised against the soluble L-amino acid oxidase protein of 50 kDa. These results suggest that the 36 kDa peptide present in purified photosystem II complexes from A. nidulans might be a processed form of the soluble 50 kDa L-amino acid oxidase protein.
Selective Biotransformation of Monoterpenoids by Cell Suspensions of Petroselinum crispum
Authors: Gbolade A. A. , Lockwood G. B.
Published: August 2018

Cell suspension cultures of Petroselinum crispum (Mill) Nyman cultivars “Paramount” and “Plain-leaved” were capable of biotransforming exogenously supplied geraniol largely into nerol and minor quantities of neral and geranial. Maximal conversions into nerol (32-36%); and neral: < 1% (cult. “Plain-leaved”), <5% (cult. “Paramount”) were usually recorded by 24 h. Over the incubation period a low proportion of the substrate, 32-40% was involved in biotransformation. Cyclic and other acyclic monoterpenoids were not biotransformed.
New Dihydrobiflavones from the Moss Plagiomnium cuspidatum
Authors: Anhut Siegbert , Seeger Tassilo , Zinsmeister H .-Dietmar , Geiger Hans
Published: August 2018

In Plagiomnium cuspidatum the three new dihydrobiflavones 2,3-dihydro-5′-hydroxyam entoflavone, 2,3-dihydro-5′,3‴-dihydroxyamentoflavone and 2,3-dihydro-5′-hydroxyrobustaflavone were detected.
Comparative Investigations on the Metabolism of the Herbicide 2-(2,4-Dichlorophenoxy)-propionic Acid in Plants and Cultured Cells of Tomato
Authors: Bärenwald G. , Schneider B. , Schütte H. R.
Published: August 2018

Akademie der Wissenschaften der DDR , Institut für Biochemie der Pflanzen, Weinberg 3, Halle/Saale. The metabolism of [1-14C]2-(2,4-dichlorophenoxy)-propionic acid was studied in excised plants and cell suspension cultures of tomato. It was rapidly taken up and metabolized by both the plants and the cultured cells. The metabolites, isolated by extraction with aqueous acetone, separated and purified by TLC and HPLC, were identified by chemical and spectrometric methods. Conjugates with carbohydrates were detected. Glucose, diglucose as the main conjugating moiety, and triglucose were found as carbohydrate components within the conjugates. Almost the same conjugates occurred in plants and cultured cells.
PS IIα/ß Heterogeneity during the Cell Cycle of the Unicellular Green Alga Chlorella fusca
Authors: Scheffczyk Berthold , Damm Ingo , Grimme L. Horst
Published: August 2018

Fluorescence induction m easurem ents indicate a PS IIα,β heterogeneity in the unicellular green alga Chlorella fusca. Under normal light the relative amount of PSα II is decreasing from 63% to 43% during the first 8 h of the cell cycle. The rate constant kα shows a concomitant decrease by 20% in the first 4 h. The relative amount and antenna size of PS IIα is restored in the dark. In contrast, PS IIβ - centres show the same rate constant during the whole cell cycle. Under low light kα is increased by approximately 30% over the cell cycle, whereas no change of kβ is observed. It is concluded that the PS II organization of Chlorella is changed both during the cell cycle and the adaptation to light intensity by a complex regulation (i) involving the antenna size of α-centres and (ii) changing the quantitative relationship of fast and slow reaction centres.
Isolation, Chemical Characterization, and Immunohistochemical Localization of a Protein from the Basolateral Plasma Membrane of the Rat Intestinal Absorptive Cell
Authors: Schiechl H.
Published: August 2018

Rat, Intestinal Absorptive Cell, Basolateral Plasma Membrane, Protein Isolation. Chemical Characterization The protein pattern of the basolateral membrane (BLM) of the rat small intestinal absorptive cell shows about 20 major and a multitude of minor bands. A simple and efficient method is described for isolation and purification of a major protein in the 17 kDa molecular weight (M W)-range called Prot 17 . The isolated BLM of intestinal epithelial cells was dissolved in buffer 1 (Tris/HCl, 2% SD S, 10% glycerol, 5% β-m ercaptoethanol. pH 6.8) and subsequently dialyzed for 4 h against buffer 2 (Tris/glycine, pH 8.3) and then for 12 h against buffer 2 containing 25% methanol. The resulting precipitate contained Prot 17 and phospholipids in the form of liposom es. A ll other BLM proteins remained dissolved in the supernatant. Chemical characterization of Prot 17 suggested that it is an integral membrane protein amounting to about 5% of the total BLM protein. Amino acid analysis revealed a MW of 17.6 kDa. The Prot 17 molecule did not contain any PAS-positive carbohydrates. In its isolated form, and apparently also in the BLM . Prot 17 occurred as a polymerized structure with a MW of about 90 kD a. By dissolution in buffer 1 and heating to 100 °C for 1 min the complex was split into its 17 kD a subunits. By oxidation with performic acid it was also broken down into its subunits. A specific antiserum against Prot 17 was obtained from immunized Balb/c mice. Immunofluorescence labelling of rat small intestinal sec­tions with this serum showed that Prot 17 was not a BLM -specific protein. It occurred in both plasma membrane domains of the intestinal absorptive cell.
Reticulosphaera socialis n. gen., n. sp., ein plasmodialer und phagotropher Vertreter der heterokonten Algen / Reticulosphaera socialis n. gen., n. sp., a Plasmodial and Phagotrophic Representative of the H eterokont Algae
Authors: Grell Karl G.
Published: August 2018

Reticulosphaera socialis n. gen.. n. sp., a protist deriving from the Caribbean Sea. could be isolated and cultivated. The life cycle consists of a benthic and a pelagic phase. Spherical cells, characteristic of the benthic phase, are united by a common reticulopodium by means of which they capture and digest diatoms (“reticulopodial digestion”). When food gets exhausted, the cellular association (plasmodium) disintegrates into single cells resembling amoebae (“individualization”). After some time, they transform into heliozoan-like cells which float in the seawater. Under unfavorable conditions the spherical cells may encyst. When the diatoms run short and illumination is sufficient, they can survive by means of their plastids. though for a limited time only. Electron microscopical investigations showed that the heliozoan-like cells have not only pseudopodia used as floating projections, but also two flagella. One of the flagella induces an eyespot in a nearby plastid. This situation is characteristic of the so-called heterokont algae (Chrysophyceae, Xanthophyceae). Classification of Reticulosphaera socialis - and a light-microscopically similar species: Chlorarachnion reptans - is discussed.
Accumulation of Unusual Phenylpropanoids in Transformed and Non-Transformed Root Cultures of Coreopsis tinctoria
Authors: Thron Ulla , Maresch Lothar , Beiderbeck Rolf , Reichling Jürgen
Published: August 2018

Using Coreopsis tinctoria liquid cultures of Agrobacterium rhizogenes transformed roots (socalled “hairy roots”) and non-transformed roots have been established. The production of different phenylpropanoid com pounds by these cultures grown in light or darkness, respectively, was compared. Whereas the com position of phenylpropanoids in the root cultures was not influenced by the culture conditions, the total production of phenylpropanoids as well as the formation of single com pounds each analyzed were higher in darkness than in light. The biomass production of the transformed root cultures exceeded that of non-transformed root cultures by a factor of 2.6. A t the same time com pound accumulation paralleled the biomass production, so that the dark grown transformed root cultures were producing maximum yields of several phenylpropanoids, especially l′-isobutyryloxy-eugenol-isobutyrate (7 mg per culture flask during a single culture passage).
Variation in the Components of Head Extracts of Workers and Queens of Apis mellifera intermissa Buttel-Reepen
Authors: Crewe Robin M. , Moritz Robin F. A.
Published: August 2018

Quantitative analysis of nine major com ponents of the head extracts of workers and queens of Apis mellifera intermissa was carried out. Q ueen and worker component patterns were distinct. The patterns of both castes changed with age, and the worker patterns were also affected by being reared in the absence of a queen.

The genetic variance of the component composition of the extracts was found to be higher in the queens than the workers. This may have functional significance in the recognition by workers of their own queen.
Comparative Enzymology of Sulfite Oxidation in Thiocapsa roseopersicina Strains 6311, M1 and BBS under Chemotrophic and Phototrophic Conditions
Authors: Dahl Christiane , Trüper Hans G.
Published: August 2018

The purple sulfur bacterium T. roseopersicina is able to grow chemoautotrophically in the dark under micro- to semiaerobic conditions. Under the latter cell yield and growth rate are considerably reduced. During chemo- and phototrophic growth reduced sulfur compounds are metabolized by the same pathway, i.e. oxidized to sulfate via adenylylsulfate. APS reductase (EC 1.8.99.2), ADP sulfurylase (EC 2.7.7.5) and ATP sulfurylase (EC 2.7.7.4) could be shown in all the strains tested, whereas only strain BBS contained an AMP independent sulfite-oxidizing activity under photo- as well as under chemotrophic conditions. Not only ADP but also ATP sulfurylase perform a dissimilatory function proven by their high specific activities. In contrast to the enzyme of T. roseopersicina strain 6311 APS reductases from strains M1 and BBS are strictly membrane-bound. The enzyme from strain M1 was solubilized, enriched and characterized. While the KM values of purified APS reductase remain unaffected, specific activities of APS reductase, ATP and ADP sulfurylase are increased substantially under chemotrophic growth conditions.
Nicotinic Acid Conjugation in Plants and Plant Cell Cultures of Potato (Solanum tuberosum)
Authors: Köster Susanne , Upmeier Barbara , Komossa Dieter , Barz Wolfgang
Published: August 2018

The conversion of nicotinic acid to N-conjugates by either m ethylation or glucosylation has been investigated in leaves and tubers from potato plants, in potato callus and suspension cultures and in plants regenerated from such cultures. While nicotinic acid-N-glucosyltransferase activity could be detected in the cells and tissues at each level of differentiation, the N-methyltransferase (trigonelline formation) was only found in organized leaf tissue.
Metabolie Conversions of Trichothecene Mycotoxins: De-esterification Reactions Using Cell-Free Extracts of Fusarium
Authors: Udell Michael N. , Dewick Paul M.
Published: August 2018

A crude cell-free extract from cultures of Fusarium sp. strain C37410-90 possessed significant esterase activity and hydrolyzed the trichothecene mycotoxin 3-acetyldeoxynivalenol (3-AcDON) to deoxynivalenol (DON) in high yield. Smaller amounts of 15-acetyl- and 3,15-diacetyl-esters of DON were also formed. The extract was capable of hydrolyzing a range of natural and semisynthetic trichothecene esters, and showed a high degree of regioselectivity towards position 3.3,4,15-Triacetylscirpentriol (TAS) was efficiently hydrolyzed to 4,5-diacetoxyscirpenol (DAS), and no further transformation was observed. The enzyme activity was partially purified.
Changes in the Wall-Bound Glycosidase Activities during the Cell Cycle in a Synchronous Culture of Catharanthus roseus
Authors: Amino Shin-ichi , Komamine Atsushi
Published: August 2018

The activities of some of the glycosidases in cell walls were measured during the cell cycle in a synchronous culture of Catharanthus roseus (L.) G. Don. The salt-extractable α-galactosidase activity increased during the G 2 phase, whereas β-glucosidase and β-galactosidase activities in cell walls increased during the G 1 phase after cytokinesis.
Preparation and Isolation of Antibodies to Human MHC Class II alpha Chains by Aid of Synthetic Peptides
Authors: Chersi Alberto , Romano Teresa F. , Chillemi Francesco
Published: August 2018

Abstract Antibodies against HLA Class II alpha chains were prepared by using as immunogens synthetic peptides selected from the HLA -DQ 1 alpha chains sequence.

Antibodies raised against peptide E2 , a 15-residue fragment of the polymorphic first domain, reacted preferentially with cells with the DQ 1 phenotype; however, despite the low sequence homology of this fragment with corresponding segments in DQw2 and DQw3 alpha chains, a partial crossreactivity with cells not expressing the DQw 1 specificity was detected. Antibodies to peptide H , selected from the monomorphic frame, might be specific for DO alloantigens, and presumably do not react with DR antigens.

The two peptides, in addition, bind anti-Class II antibodies from the serum of a rabbit immunized with human cells, and appear to represent immunogenic linear determinants in the native glycoprotein molecule.
Spin Label Studies of Erythrocytes during Storage of Blood
Authors: Pessina G. P. , Ciccoli L. , Picchi M. P. , Fanetti G.
Published: August 2018

The kinetic behavior of the spin label MAL-6 in the interaction with differently aged human erythrocyte membranes was evaluated by monitoring the rate of disappearance of the room temperature ESR signal due to the MAL-6 spin label added to blood after storage at 4 °C or after incubation of red cells at 37 °C in a protein-free medium. After 35 days of blood storage or 60 h of erythrocytes incubation at 37 °C the decrease of the intensity of the MAL-6 ESR spectra in respect to control samples is markedly enhanced and the correspondent kinetic constants significantly increase. Signal decay of MAL-6 is a further proof that during storage of blood under blood bank conditions or during an artificial ageing of erythrocytes at 37 °C, profound modifications occur in the human erythrocyte membrane.
Photoresponses from Cells in the Fly’s Eye which are not Visual Cells
Authors: Hochstrate Peter
Published: August 2018

It is shown that light elicits distinct responses from cells in the fly’s eye which are different from photoreceptors. These cells are designated as “slow cells” because of their sluggish response characteristics. Like the visual cells the slow cells depolarize upon light stimulation, but the time course of their responses is clearly different from that of the photoreceptors. Furthermore, the intensity necessary to evoke a given response amplitude is considerably higher in slow cells than in photoreceptors. Several lines of evidence indicate that the slow cell response is caused by light absorption through the visual pigment rhodopsin in the peripheral photoreceptors R 1 -6. The slow cells are electrically coupled among each other, as demonstrated by application of local light stimuli and injection of the fluorescent dye Lucifer Yellow . The identity of the slow cells and the mechanism of response generation are discussed.
Phloroglucinol Derivatives as Potent Photosystem II Inhibitors
Authors: Yoneyama Koichi , Konnai Makoto , Honda Ichiro , Yoshida Shigeo , Takahashi Nobutaka , Koike Hiroyuki , Inoue Yorinao
Published: August 2018

Studies on structure/activity relationships of phloroglucinol derivatives that had been designed based on the structures of grandinol and homograndinol. potent photosystem II (PS II) inhibitors in Eucalyptus grandis, revealed that two electron-withdrawing groups which differ by their electron-withdrawing power on a phloroglucinol nucleus were essential for activity. A larger difference in the electron-withdrawing power between the two groups enhanced the activity, and 3-nitro-phloroglucinecarboxamides and the corresponding thioamides were the most active ones when they had proper lipophilic side chains. Their binding domain seems to overlap with those of DCMU and atrazine, whereas they may approach to the site in a similar manner to that of phenol type inhibitors. Accordingly, the phloroglucinol derivatives represent a new type of PS II inhibitors.
The Aurachins, Naturally Occurring Inhibitors of Photosvnthetic Electron Flow through Photosystem II and the Cytochrome b6/f-Complex
Authors: Oettmeier Walter , Dostatni Ralf , Majewski Christoph , Höfle Gerhard , Fecker Thomas , Kunze Brigitte , Reichenbach Hans
Published: August 2018

A third group of antibiotics, the aurachins, have been isolated from the myxobacterium Stigmatella aurantiaca. The aurachins chemically are quinolones. and four of them (aurachins A-D) have been tested for their inhibitory activity in photosystem II and cytochrome b/c-complexes. Aurachin C is the best inhibitor in photosystem II (pI50-value 7.2); its biochemical behaviour being the same like that of other photosystem II herbicides. Both aurachins C and D are also excellent inhibitors in the cytochrome b6/f-complex (pI50-values of 7.00 and 7.49. respectively). In its mechanism of action, aurachin C resembl|es antimycin, whereas aurachin D is different from either antimycin or myxothiazol.
Q a Binding to D2 Contributes to the Functional and Structural Integrity of Photosystem II
Authors: Vermaas Wim , Charité Jeroen , Shen Gaozhong
Published: August 2018

Two D2 mutants were created with a site-directed mutation near the presumable binding site of QA. In one of the mutants, in which Trp-253, the aromatic residue potentially involved in facilitating electron transport from pheophytin to QA and/or in binding of Q A, had been replaced by Leu, PS II was undetectable in thylakoids. This mutant is an obligate photoheterotroph. In another mutant the Gly-215 residue, located next to the His residue that is proposed to bind QA and Fe2+, was mutated to Trp. This mutation leads to a rapid inactivation of oxygen evolution capacity in the light, and to a virtual elimination of the potential to grow photoautotrophically, but does not greatly affect the number of photosystem II reaction centers on a chlorophyll basis. We propose that proper binding of QA to the photosystem II reaction center complex is a prerequisite for stability of the photosystem II complex. Impairment of Q a binding leads to rapid inactivation of photosystem II, which may be followed by a structural disintegration of the complex.
Studies on the Herbicide Binding Site in Isolated Photosystem II Core Complexes from a Flat-Bed Isoelectrofocusing Method
Authors: Giardi M. T. , Barber J. , Giardina M. C. , Bassi R.
Published: August 2018

Isoelectrofocusing has been used to separate various chlorophyll-protein complexes of photosystem two (PS II). Light-harvesting complexes containing chlorophyll a and chlorophyll b (LHC II) were located in bands having p/s in the region of 4.5. At slightly higher pH other light-harvesting complexes containing little or no chlorophyll b were found. In the most basic region of the isoelectrofocusing gel, were located PS II core complexes characterized by con­taining the proteins of CP47, CP43, D 1, D 2 and α-subunit of cytochrome b559. The number of PS II core bands depended on the particular conditions employed for the separation procedure and in some cases were contaminated by CP 29. It is suggested that this heterogeneity resulting from different protonation states of the PS II.

The least-acidic PS II core complex (pI 5.5) was found to bind the herbicides atrazine, diuron and dinoseb. In contrast, a PS II core complex with a p / of 4.9 bound only diuron. Its inability to bind atrazine was shown to be due to the low pH but no such explanation could be found for dinoseb.

When atrazine-resistant mutant Senecio vulgaris was used, no binding of radioactive atra­ zine was observed with the PS II cores having a p i of 5.5. It is therefore suggested that the normal atrazine binding observed with PS II cores involves the high affinity site detected with intact membranes. With the PS II cores, however, this site has a reduced affinity probably due to structural modification in the D 1-polypeptide resulting from the isolation procedures.
Sequence Analysis of Four Atrazine-Resistant Mutants from Rhodopseudomonas viridis
Authors: Ewald G. , Wiessner C. , Michel H.
Published: August 2018

Four atrazine-resistant mutants from the purple bacterium Rhodopseudom onas viridis were isolated. Sequence analysis revealed three different mutant strains carrying mutations in the herbicide-binding pocket: i) M AV 2: L 212-Glu → Lys, ii) M AV 3: L216-Phe → Ser and iii) MAV 4 = MAV 5: L217-Arg → His, L220-Val → Leu. Except M AV 3 all Rps. viridis mutants are different from those selected by their resistance towards the closely related triazine terbutryn.
Mode of Evolved Photooxidant Resistance to Herbicides and Xenobiotics
Authors: Jansen Marcel A. K. , Malan Christo , Shaaltiel Yoseph , Gressel Jonathan
Published: August 2018

A few species have evolved resistance to paraquat after repeated selection. As paraquat still inhibited NADP reduction, we hypothesized that resistance might be due to (a) detoxification of the paraquat-generated active oxygen species and (b) that resistant plants would have some cross resistance to other xenobiotic oxidants as well as to photoinhibition, which we subsequently demonstrated. The levels of plastid isozymes of the oxygen detoxification pathway: (CuZn) superoxide dismutase, ascorbate peroxidase and glutathione reductase were genetically higher in the resistant than in the sensitive biotype of Conyza bonariensis through the F2 generation. Resistance was suppressed by chelators of copper and/or zinc. Intact chloroplasts from resistant plants had less membrane damage with and without paraquat, than those from sensitive plants. Resistant Conyza plants recover from paraquat inhibition of photosynthesis in 3-4 h in high light, whereas sensitive plants died. Both resistant and sensitive plants recovered from paraquat in 3-4 h in low light intensities. Paraquat-resistant Conyza plants were cross-tolerant to SO2, atrazine, acifluorfen and to photoinhibition. Drought-tolerant maize inbreds were cross-tolerant to paraquat, SO2 and acifluorfen (compared to sensitive lines) and they also possessed higher levels of (Cu/Zn) superoxide dismutase and glutathione reductase. The tolerance to oxidant stresses in Conyza and maize increases with plant age, suggesting that the shift to resistance is a constitutive, earlier expression of the genes normally expressed later in development.
Recent Advances in the Mode of Action of Diphenyl Ethers and Related Herbicides
Authors: Scalla René , Matringe Michel , Camadro Jean-Michel , Labbe Pierre
Published: August 2018

Several hypotheses have been proposed to explain the light-dependent phytotoxicity of diphenyl ethers and related herbicides: inhibition of photosynthesis; activation of herbicides by light, by the photosynthetic electron transfer chain or by excited forms of carotenoids; and interaction with the biosynthesis of tetrapyrrole pigments. It is shown that the most likely mode of action consists in inhibiting the enzyme protoporphyrinogen oxidase. As a consequence, protoporphyrinogen is oxidized non-enzymatically to protoporphyrin IX. The latter molecule is a powerful photosensitizer, able to generate singlet oxygen in the light and thus to induce peroxidative destruction of membrane lipids.
Surface Charge Density Changes in Isolated Photosystem II Membranes Induced by Depletion of the Extrinsic Polypeptides of the Oxygen Evolving System
Authors: Ivanov Alexander G. , Busheva Mira C. , Velitchkova Maya Y.
Published: August 2018

Treatment of PS II particles with either 1 M NaCl or alkaline Tris (1 M , pH 8.4) caused a considerable decrease in the average net negative surface charge density, concomitant with depletion of the extrinsic 17, 24 and 33 kDa proteins of the oxygen evolving complex from the membranes. The partial recovery of the values for surface charge in both NaCl- and Tris-treated membranes was registered after reconstitution experiments with the three proteins. These results are compared with the data for the charge densities of the thylakoid membranes, to examine the role of the three extrinsic proteins in the formation of heterogeneous arrangement of surface charge across the appressed (granal) thylakoids.
Dominance of Celestial Cues over Landmarks Disproves Map-Like Orientation in Honey Bees
Authors: Menzel Randolf , Chittka Lars , Eichmüller Stefan , Geiger Karl , Peitsch Dagmar , Knoll Peter
Published: August 2018

A recent model of landmark orientation by the bee assumes that the memory of the landmarks is arranged in a kind of a mental map. Our experiments disprove this assumption and show that the sun compass dominates the orientation without any indication of mental operations within a map-like representation of landmarks or of compass vectors and distances.
The Influence of 5-Aminolevulinic Acid on Protochlorophyllide and Protochlorophyll Accumulation in Dark-Grown Scenedesmus
Authors: Kotzabasis Kiriakos , Senger Horst
Published: August 2018

The intermediate of chlorophyll biosynthesis, 5-aminolevulinic acid (ALA ), is a necessary prerequisite for the formation of protochlorophyllide (PChlide) and protochlorophyll (PChl) in the dark. The application of ALA to a dark-grown culture of the pigment mutant C-2 A′ of Scenedesmus obliquus increased the amount of PChlide 30-fold and the amount of PChl about 10-fold. The rates of ALA-dependent formation of PChlide and PChl reach their maximum values at different concentrations of added ALA . Similarly, the kinetics of PChlide and PChl formation in cells incubated with ALA are different. Cells of Scenedesmus mutant C-2 A′ incubated with various concentrations of ALA for different periods provide a good tool for future studies differentiating between PChlide and PChl metabolism . − The incorporation of Chl deriving from either PChl or PChlide into different pigment protein complexes is discussed.
Isolation and Synthesis of New Bile Pigments Possibly Related to the Biosynthesis of the Phycocyanin Chromophore
Authors: Lüönd Eva Benedikt , Köst Hans-Peter , Rüdiger Wolfhart
Published: August 2018

After incubation with 5-aminolevulinic acid and cysteine or 5-amino-levulinic acid and glutathione, Cyanidium caldarium excreted two new bile pigments 1 and 2. Their structures are identified by spectroscopical methods. By chemical addition of cysteine, glutathione and hydrogen sulfide to the ethyliden double bond of E-phycocyanobilin, the bile pigments 3-6 were obtained.