bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the Safener Benoxacor on the Metabolism of Metolachlor in Corn
Authors: Cottingham C. K. , Hatzios K. K.
Published: August 2018

The herbicide safener benoxacor (CGA -154281) is effective in protecting corn from meto­lachlor injury. Glutathione-S-transferase (GST) activity of corn seedlings was stimulated by low concentrations of benoxacor as was the formation of a polar metabolite identified as the glutathione (GSH) conjugate of metolachlor. A similar degree of enhancement of metolachlor metabolism was observed in both a metolachlor-tolerant (’Cargill 7567’) and a metolachlor-susceptible (’Northrup-King 9283’) corn line. The total GSH content of shoots of the metolachlor-susceptible corn hybrid was not affected by benoxacor treatment, but an increase was noted for shoots of the tolerant corn hybrid. The two corn hybrids with differential tolerance to metolachlor also differ in their dose response to benoxacor with higher safener concentra­tions failing to induce or inhibit GST activity of the tolerant ’Cargill 7567’ corn line. Stimula­tion of GST activity and a corresponding enhanced rate of metolachlor metabolism can ac­count for the safening effect of benoxacor. These mechanism of action of dichloroacetamide safeners.
Effects of the Herbicide Pretilachlor and the Safener Fenclorim on Glutathione Content and Glutathione-Dependent Enzyme Activity of Rice
Authors: Han Seong , Hatzios Kriton K.
Published: August 2018

The influence of individual or combined treatments of the chloroacetanilide herbicide preti­lachlor and the safener fenclorim on glutathione content and the activity of glutathione reduc­tase (GR, EC 1.6.4.2) and glutathione-S-transferase (GST, EC 2.5.1.18) of rice (Oryza sativa L., var. Lamont) was investigated in a time-course study including 0, 12, 24, 48, and 72 h peri­ods after treatment. Pretilachlor applied alone at 2 μM did not influence the levels of total or reduced glutathione of germinating rice seedlings. Fenclorim applied alone at 20 μM increased significantly the levels of total and reduced glutathione of rice seedlings at 12, 24, and 72 h after treatment. The combination of pretilachlor and fenclorim increased the levels of total and reduced glutathione of rice at all time periods. GR activity extracted from pretilachlor-treated rice seedlings was significantly lower than that extracted from untreated rice seedlings. Pretreatment of rice seedlings with the safener fenclorim increased GR activity at 12 and 24 h, but not at 48 and 72 h after treatment. GR activity extracted from rice seedlings treated with the combination of pretilachlor and fenclorim was significantly higher than that of untreated controls at 12, 24, and 48 h after treatment. Pretreatment of rice seedlings with pretilachlor reduced the activity of GST which catalyzes the conjugation of this herbicide with reduced glutathione at time intervals greater than 24 h. Pretreatment with fenclorim did not have any effect on GST activity of rice seedlings. Pretreatment with the combination of pretilachlor and fenclorim increased GST activity of rice seedlings at the 48 and 72 h periods. These results suggest that a simultaneous application of pretilachlor and fenclorim is critical for the enhance­ment of glutathione and glutathione-related enzyme activity and the protection of rice from pretilachlor injury.
Effect of a Safener Towards Thiocarbamates on Plant Lipid Metabolism
Authors: Abulnaja Khalid O. , Harwood John L.
Published: August 2018

It has been found that various thiocarbamate herbicides, known to alter surface wax and cutin synthesis, inhibit the elongation of fatty acids. We have proposed this as a mode of ac­tion of such compounds. Because it is believed that the sulphoxide metabolites of thiocarba­mates are the active intermediates, we have examined the action of 1-aminobenzotriazole (an inhibitor of sulphoxide formation) on the inhibition of very long-chain fatty acid biosynthesis. In all tissues tested, aminobenzotriazole was able to block the specific inhibitory effect of thio­carbamates on fatty acid elongation. These results add further support to our proposal that fatty acid elongation is a sensitive target site for thiocarbamate herbicides in plants.
Safeners as Corn Seedling Protectants against Acetolactate Synthase Inhibitors
Authors: Milhomme Henri , Roux Christophe , Bastide Jean
Published: August 2018

Zea mays L., cv. Potro, shoots had a higher level of resistance to imazaquin (IQ) and metsul­furon methyl (MSM) than roots. Shoot lengths were increased by pretreating the seeds with commercial 1,8-naphthalic anhydride (NA) at 1% (w/w) or oxabetrinil at 0.2% (w/w). The growth of shoots of safened seeds was unaffected by 400 nᴍ IQ and by 40 nᴍ MSM.

The in vivo activity of acetolactate synthase (ALS) extracted from corn shoots and roots was not affected by treatments with IQ or MSM , but pretreatment of seeds with NA or oxabetrinil, prior to germination, caused an increase in the level of extractable ALS from shoots. ALS activity from roots and shoots of NA-pretreated seedlings was increased to a large degree (> 40 %) when the seedlings were germinated on 40 nᴍ MSM , whereas ALS acti­vities from oxabetrinil-pretreated seedlings were enhanced to a lesser degree (≈20%). ALS from unsafened seedlings was inhibited 21% by 400 nᴍ IQ and 70% by 40 nᴍ MSM in vitro, but ALS from roots of seedlings germinated on 400 nᴍ IQ was not inhibited by 400 nᴍ IQ in vitro.
Renaissance for Hapten-Specific T Lymphocytes: Implications for Basic and Applied Research
Authors: Ulrich Hans
Published: August 2018

Protein-reactive chemicals and drugs (haptens), such as dinitro- (DNP) or trinitro-phenylated (TNP) reagents or penicillins, are potent inducers of allergic reactions in experimental animal systems as well as in humans. Hapten-specific T lymphocytes are mediators of these disorders. Like other antigens, hapten determinants on target cells are recognized by the T cell’s antigen-specific receptors exclusively in association with gene products of the major histocompatibility complex (MHC). Until recently, the nature of the complex hapten/MHC determinants remained unknown. Atypically, this fact, rather than spurring scientific investigations, caused a rapid loss of interest in haptens as T cell antigens by the majority of immunologists. This situation may now be changing, since we have recently identified MHC-binding, haptenmodified peptides which mediate cellular recognition by T cells via their antigen-specific receptors. Synthetic hapten-peptide conjugates open up new routes in studying the molecular details of hapten recognition by T cells. They may also contribute to a better understanding of what defines an antigen as an allergy-inducing “allergen”.
Chlorophyll Proteins and Lipids in Paraquat Treated Sensitive and Resistant Conyza Canadensis Leaves
Authors: Szigeti Zoltán , Sárvári Éva , Lehoczki Endre
Published: August 2018

Photosynthetic activity and molecular composition of thylakoid membranes of sensitive and atrazine/paraquat coresistant biotypes of Conyza canadensis (L.) Cronq was compared before and after 5 × 10-4 molar paraquat spraying. In contrast to the irreversibly damaged sensitive plants the Rfd values (vitality indices) calculated from parameters of fluorescence induction curves, and the in vivo CO2 fixation in resistant plants showed - after a transitory inhibition - a recovery.

Resistant thylakoids contained higher amount of PS II and LHC II, (i.e. lower relative amount of CP I) which can be the result of an adaptation process. Fatty acid composition of total leaf extract was almost the same in both biotype even after spraying. The amount of the oligomeric form of LHCP II decreased in paraquat treated sensitive thylakoids, which was in correlation with the reduction of Δ3-transhexadecanoic acid content. Decrease in oligomeric LHCP II and/or special lipids (PG) in sensitive thylakoids may change the association of LHCP II and photosystem II core as it is evidenced from lowering of the Mg2+ induced changes of the short wavelength fluorescence intensity and increase in the relative quantum requirement values. The results are discussed in connection with a possible effect of paraquat on PS II.
Non-Essential Activation of Rat Liver Porphobilinogen-Deaminase by Folic Acid
Authors: Noriega Guillermo O. , Juknat Adela A. , Batlle Alcira M. del C.
Published: August 2018

This report demonstrates the ability of folic acid to activate rat liver porphobilinogen-deaminase (PBG -D). Lineweaver-Burk analysis revealed an increase in Vmax (38%) without affecting the Km. In the concentration range assayed, secondary replots of 1/Δslope and 1/Δintersect versus 1/[folic acid] yielded straight lines, indicating the binding of a single molecule of activator to the enzyme PBG-D , with a KA = 1.66 mᴍ. Results presented here show that folic acid acts as a non-essential activator (α = 1; β = 1.6).

The activating effect of folic acid has been observed employing the 35-70% ammonium sulphate precipitated fraction, desalted by dialysis or gel filtration, whereas no action was detected when other partially purified PBG -D preparations were utilized as the enzyme source, suggesting either the presence of sites saturated for the activator, or the existence of a different structural protein conformation, or both.
Effects of Chloroquine on the Photosensory Membrane Turnover and the Ultrastructure of Lysosome-Related Bodies of the Crayfish Photoreceptor
Authors: Schraermeyer Ulrich
Published: August 2018

The effect of chloroquine in combination with bright light on the ultrastructure of crayfish (Orconectes limosus R.) photoreceptors was investigated in vivo. Chloroquine had several effects upon the crayfish retina. Multivesicular bodies (MVB) that are involved in lysosomal degradation of photosensory membrane were altered in ultrastructure. MVB frequently contained smaller MVB in a state of more advanced membrane degradation. Additionally screening pigment-like granules appeared in MVB. MVB accumulated in and filled the retinular cell cytoplasm just proximal or distal to the basement membrane which indicated inhibition of photosensory membrane degradation. Under chloroquine treatment rhabdom degradation appeared to be inhibited, as rhabdom diameter was less reduced under these conditions.

Also chloroquine caused accumulation of screening pigment granules in glial cells within the lamina ganglionaris.
Evidence for a Pathway of Distal Screening Pigment Granules across the Basement Membrane of the Crayfish Photoreceptor
Authors: Schraermeyer Ulrich
Published: August 2018

The distal pigment cells of Orconectes limosus contain two layers of large electron lucent vacuoles that are separated by layers of small right-angled platelets adjacent to the crystalline cones. The crystalline cones of the dioptric apparatus of this species have evaginations into the distal pigment cell cytoplasm. In photoreceptors of Orconectes limosus and Procambarus clarkii a dark pigment accumulation site was detected just distal to the basement membrane at the edges of each retina. These pigment accumulations occurred independent of the state of light adaptation. Ultrastructurally the pigment granules at this accumulation site resemble distal screening pigment granules according to their size (up to 1.2 μm in diameter) and fibrous structure. Distal screening pigment granules were also found in tube-like cell processes or extracellularly within and proximal to the retinal basement membrane, indicating pigment transport to and across the basement membrane. Proximal to the basement membrane screening pigment granules were also observed disintegrated to a gravel-like electron dense material in widely branched cells. Evidence was found that an electron dense material, probably resulting from disintegrating screening pigment granules, was incorporated in the integument of the eyestalk. Four hours after injection of gold particles into the eye stalk distal to the retina they were detected inside and proximal to the retinal basement membrane.
Notes: O6-Alkylguanine-DNA Alkyltransferase in the Chick Embryo during Development
Authors: Ignatius Anita , Tempel Karlheinz
Published: August 2018

In the whole embryo, O6-alkylguanine-DNA alkyltransferase (AT) activity increased until day 9 of development and declined sharply after day 13. AT activity of the liver was greatest between day 12 and day 20 and decreased fast after hatching. In the brain, AT activities reached a maximum at day 17 and 18 and declined sharply after hatching. At two developmental stages with different AT activities (day 10 and day 17) DNA alkylation in the brains was estimated 6, 12, 24 und 48 h after administration of N-methyl-N-nitrosourea in ovo by viscometric measurement of DNA fragmentation. The high AT activities of the chicken embryo brain at the 17th day of development correlated with minor DNA fragmentation following a repair period of 12-24 h. It is suggested that the high basal level of AT in the chick embryo might have a protective function against the persistence of the genotoxic lesion O6-methylguanine during development.
Labeling and Isolation of Hemes from Scenedesmus
Authors: Drechsler-Thielmann Beate , Dörnemann Dieter , Senger Horst
Published: August 2018

Protoheme and small quantities of heme a were isolated and purified from the wild type and the developmental mutant, C-2 A′, of Scenedesmus obliquus. In fast growing synchronized WT cells and greening cells of the mutant protoheme could be labeled with [1- 14C]glutamate and [2-14C]glycine. The labeling of heme a was ambiguous and of minor quantity. During rapid chlorophyll biosynthesis the turnover of protoheme was determined by a pulse-chase experiment to have a half-life of 2 h. At the current stage of investigations the question, whether [2-14C]glycine is incorporated into protoheme via the Shemin pathway or via photorespiration or refixation of 14CO2 during general metabolism remains open.
Cereal Grain Alk(en)ylresorcinols Protect Lipids against Ferrous Ions-Induced Peroxidation
Authors: Struski Dariusz G . J. , Kozubek Arkadiusz
Published: August 2018

Resorcinolic lipids, significant constituents of cereal grains are long chain (C 13 -C 27) derivatives of 1,3-dihydroxy-5-alk(en)ylbenzene. It was shown that due to their phenolic nature resorcinolic lipids are effective in protection against fatty acids peroxidation. The phospholipid bilayers appeared to be also protected in the presence of these compounds. The maximal inhibition of peroxidation was 50-90% with IE50 values in the range of 0.8 5-3.6 mol% of resorcinolic lipids.
Embryotoxische Wechselwirkungen zwischen einem Hydrolysenprodukt des Thalidomids und dem Tensid Tween 20 bei der Maus / Embryotoxic Interactions between a Hydrolysis Product of Thalidomide and the Surfactant Tween 20 in Mice
Authors: Kocher-Becker Ursula , Kocher Walter , Ockenfels Heinrich
Published: August 2018

N,N-phtaloyl-ʟ-glumatic acid (NPLG), a hydrolysis product of thalidomide, and the surfactant Tween 20 were co-administred intraperitoneally to pregnant NMRI mice on days 9a and 8⅔ p.c. at doses where the hydrolysis product as well as the surfactant alone induce minimal embryotoxicity. The combined substances (350 mg/kg NPLG + 1.0 ml/kg Tween 20) caused a potentiative teratogenic and an additive embryolethal response. Enhancement of the amount of Tween 20 in the combinations to 2.5 ml/kg led to the same potentiative teratogenic and, in addition, potentiative embryolethal response. Distribution studies using 14C-NPLG showed a strongly increased NPLG content in the maternal plasma under the influence of 2.5 ml/kg Tween 20 but not after co-administration with 1.0 ml/kg Tween 20.

The malformations obtained were of the same type in all groups and mostly located in the vertebrae and ribs. These axial and paraxial defects were frequently more severe and included more affected elements after application of the combined than of the single substances. Extension of our experiments with the combined substances to treatment days 8½ and 9½ p.c. revealed that the first affected segment shifts in caudal direction depending on an increasing embryonal age at treatment. Limb malformations occurred at a low frequency; most of them were of the same type as described in cases of human thalidomide embryopathy.
Purification And Characterization Of Ceql Restriction Endonuclease
Authors: Izsvák Zsuzsa , Jobbágy Zsolt , Duda Ernö
Published: August 2018

Ceql, a type II restriction endonuclease, an isoschizomer of EcoRV was purified to apparent homogeneity by a combination of salt precipitation, ion exchange, dye affinity and hydrophobic interaction chromatographies. The crude enzyme was present in the form of large aggregates that could be pelleted by high speed centrifugation. The enzyme was not associated with cellular membranes, though non-ionic detergents lowered the apparent size of the aggregates. The purified enzyme also showed a tendency to form large molecular mass (66-600 kDa) complexes under physiological conditions, in the absence of cleavable DNA. The enzyme formed smaller complexes in the presence of DNA and non-ionic detergents and dissociated into subunits (and undergoes reversible loss of activity) in the presence of high concentrations of salts. According to SDS gel electrophoresis and sedimentation analysis the molecular mass of the monomer 32 ± 2 kDa. The enzyme had a rather broad pH optimum, extending into the alkaline range and lost specificity and activity in buffers below pH 6
Inhibition Of Plant Acetyl-Co A Synthetase By Alkyl-Adenylates
Authors: Golz Andrea , Lichtenthaler Hartmut K.
Published: August 2018

The plant acetyl-CoA synthetase (ACS) is bound to the plastids and provides acetyl-CoA, the starting substrate for de novo fatty acid biosynthesis in plastids. This enzymic reaction, which consumes ATP and releases AMP, can be inhibited by different alkyladenylates such as ethyl-, isopropyl-, propyl- or allyl-adenylates as is shown here. The inhibition mechanism is competitive with respect to ATP and non-com petitive with respect to acetate. I50-values and the inhibition constants K( (ATP), Ki (acetate) and Kii (acetate) are given. The results suggest that, also in plants, acetyl-adenylate is the endogenous intermediate in the enzymic formation of acetyl-CoA from acetate by acetyl-CoA synthetase
Modulating Luminol-Dependent Chemiluminescence Of Neutrophils By Flavones
Authors: Shani W. Krol, J. , Czuba Z. , Scheller S.
Published: August 2018

The effect of 14 flavones on luminol-dependent chemiluminescence of neutrophils was studied in vitro. Chemiluminescence was used in this study as an indicator for the production of a reactive oxygen species by neutrophils, stimulated by phorbol myristate acetate. While flavone- 8-acetic acid, and most of the compounds tested, inhibited chemiluminescence, flavone and its 5-hydroxy-7-methoxy derivatives enhanced it by up to 150%. The most active inhibitors of photon emission were the glycosides. These results indicate that lipophilicity and some structural determinants modulate the chemiluminescent capacity of neutrophils
Different Effect Of Dgtp On 2'-Deoxyadenosine Metabolism In Mitochondria And Cytosol
Authors: Greger Janusz , Krystyna Fabianowska-Majewska
Published: August 2018

Two enzymes participating in 2′-deoxyadenosine (dAdo) metabolism: dAdo kinase (dAdoK EC 2.7.1.76) and adenosine deaminase (ADA, EC 3.5.4.4) were partially purified from rat liver mitochondria and cytosol and influence of nucleosides and nucleotides on the activity of these enzymes were investigated. Mitochondrial and cytosol dAdoK are separate proteins, while ADA from both subcellular fractions possesses similar physical properties. dGTP, a com petitive inhibitor of mitochondrial dAdoK, inhibits cytosol ADA in a mixed way but activates mitochondrial ADA and cytosol dAdoK. A possible effect of dGTP on dAdo metabolism in mitochondria and cytosol is discussed
Various Metallopheophorbides as Substrates for Chlorophyll Synthetase
Authors: Helfrich Michael , Rüdiger Wolfhart
Published: August 2018

Pheophorbide a was prepared from a mixture of chlorophylls a and b by differential extraction with HCl and saponification. The insertion of the following metal ions was investigated: Mg, Zn, Co, Cu, Ni. In the enzyme test with chlorophyll synthetase, the metallopheophorbides fall into two categories: the Mg- and Zn-complexes are good substrates, the Co-, Cu- and Ni-complexes are neither substrates nor competitive inhibitors for the enzyme reaction. This corresponds to two categories of complex structures: Mg- and Zn-porphyrins prefer pentacoordinate square-pyramidal structures, Co-, Cu- and Ni-porphyrins prefer tetracoordinate square-planar structures. A model for substrate binding to chlorophyll synthetase is proposed.
Effect of Tentoxin on the Activation and on the Catalytic Reaction of Reconstituted H+-ATPase from Chloroplasts
Authors: Max-Volmer Petra Fromme , Friedrich-Schiller Ingo Dahse , Gräber Peter
Published: August 2018

The proton-translocating ATPase from chloroplasts, CF0F1, was isolated, purified and reconstituted into asolectin liposomes. The effect of the energy transfer inhibitor, tentoxin, on different functions of the enzyme was investigated. Tentoxin does not inhibit the nucleotide release during energization by a pH /ΔΨ jump, i.e. the activation of the enzyme is not influenced. ATP synthesis driven by a pH /ΔΨ jump and multi-site ATP hydrolysis are completely inhibited by tentoxin, whereas uni-site ATP hydrolysis is not influenced.
A Herbicide Resistant Euglena Mutant Carrying a Ser to Thr Substitution at Position 265 in the D1 Protein of Photosystem II
Authors: Aiach A. , Ohmann E. , Bodner U. , Johanningmeier U.
Published: August 2018

A herbicide resistant Euglena mutant (MSI) has been obtained by adapting wild type cells to increasing concentrations of DCMU (3-(3′,4′-dichlorophenyl)-1,1-dimethylurea). Lower resistance levels towards DCMU and metribuzin were observed in MSI when compared with Euglena or Chlamydomonas mutants with Ser 264 to Ala substitutions. RNA-sequence analysis identified a Ser to Thr change at position 265 (equivalent to position 264 in other organisms), thus making it possible to compare the influence of amino acids Ser, Ala and Thr at identical positions on the inhibitory effect of structurally different herbicides in the same species.
RNA Metabolism, DNA Damage and Cellular Resistance to X-Rays: Investigations in Chick Embryo and Rat Cells
Authors: Link A. , Tempel K. , Hund M.
Published: August 2018

Three hours after X-irradiation in vivo with 8 Gy the in vitro incorporation of [3H]uridine into total RNA of liver(L)- and brain(B)-cells of the chick embryo was reduced to 77% and 90%, respectively; the m RNA fraction was strongest inhibited. Under the same conditions, protein synthesis of L-cells declined to 62%, while protein synthesis of B-cells was not influenced. RNA and protein metabolism was not altered following X-irradiation in vitro (1.75 -56 Gy). - Compared to thymic - and splenic cells of the rat, chicken embryo cells exhibited higher constitutive poly(adenosine diphosphate-ribose)polymerase activity and lower X-irradiation-induced DNA damage. - Whereas the slight inhibition of RNA and protein synthesis by X-irradiation in ovo may be an abscopal and/or secondary phenomenon reflecting DNA and/or cellular damage, the present investigations comprising various cell types argue for an efficient DNA repair in chicken embryo cells caused, at least partly, by a high constitutive activity of DNA repair proteins.
Formation of ssb, dsb, and Uracil in Monofilarly and Bifilarly Bromouracil-Substituted DNA Molecules
Authors: Menke Henning , Köhnlein Wolfgang
Published: August 2018

Bifilarly BU-substituted ColE 1 plasmid and monofilarly BU-substituted M 13 phage DNA were irradiated with UV light of 313 nm. Using agarose gel electrophoresis and “reversed phase” HPLC technique ssb, dsb induction and uracil formation, respectively, could be detected in the irradiated DNA in dependence on the UV fluence. The analysis of the strandbreaks in bifilar Col E1 DNA shows a significant part of directly induced dsb.

Cross sections of ssb induction from 4.1 m2/J x 107 in 28%, 3.9 m2/J x 107 in 55% and 3.1 m2/J x 107 in 8 5 -9 0% BU-substituted DNA were calculated. The cross section for dsb induction was found to be 0.04 m2/J x 107, estimated from the linear part of the fluence effect curve. In monofilar M13 DNA a linear fluence effect curve for dsb induction was obtained. Excluding other than the direct production of dsb by using an in vitro approach for M13 DNA , the results strongly support the hypothesis that dsb can be induced by one photochem ical absorption event. The cross section for ssb was 3.8 m2/J x 107 and for dsb 0.05 m2/J x 107 in 41.5% monofilarly BU-substituted M13 DNA .

The comparison of ssb, dsb, and uracil production in bifilar and monofilar DNA with similar BU substitution showed no significant difference between the two DNA systems (ColE 1, M 13), indicating that the location of BU molecules in one or in both DNA strands will not lead to a different number of lesions after UV313 exposure.
Interaction of 2 ,3 -O-(2,4,6-Trinitriphenyl)adenosine Diphosphate and 2,4,6-Trinitrophenol with Thylakoid Membrane Proteins
Authors: Ponse Gudrun , Thelen Renate , Strotmann Heinrich
Published: August 2018

2′,3′-O-(2,4,6-trinitrophenyl)ADP (= TNP-ADP) is a competitive inhibitor of photophosphorylation of A DP. Here, the interaction of TNP-ADP with the H+-translocating chloroplast ATPase and other thylakoid membrane proteins was studied more in detail and compared with the interactions of the parental compounds ADP and 2,4,6-trinitrophenol (= picric acid). The following results were obtained:

(1) Preilluminated thylakoids incorporate about 1 nmol [14C]ADP per mg chlorophyll or the same amount of T N P-[14C]ADP in the following dark. If T NP-[I4C]ADP is present in the light, however, up to 4 nmol label is bound per mg chlorophyll whereas the amount of incorporated [14C]ADP is unchanged. [14C]ADP is exclusively bound to CF1, yielding a molar ratio of 1 nucleotide per enzyme. Likewise 1 mol of 14C label per mol enzyme is found in CF, when thylakoids are illuminated in the presence of TNP-[14C]ADP; the residual bound radioactivity is related with other components of the thylakoid membrane.

(2) TNP-ADP as well as picrate are electron acceptors of the photosynthetic electron transport chain. Picramate is one main product of photosynthetic reduction of picrate. Hence at least one of the three nitro groups of the trinitrophenyl moiety is reduced to an amino group. However, additional non-identified, reactive intermediates are formed, which can bind to membrane components. About 20% of the bound label is covalently linked to membrane proteins.

(3) The patterns of covalently labeled polypeptides are identical whether [14C]picrate or TNP- [14C]ADP is employed, except for α and β subunits of CF1 which are specifically labeled in the presence of TNP-[14C]ADP. This reaction is protected by (A DP + Pi) > ATP > ADP > Pi.

Most likely radicalic intermediates of picrate or TNP-ADP photoreduction are responsible for covalent binding. In case of CF, the radicalic intermediate of TNP-ADP reduction may be accomodated by its ADP moiety into a nucleotide binding site. Subsequent covalent linkage via the reactive phenyl ring substituent seems to occur in both, the nucleotide and the Pi binding domain.
Protective Effects of Phenolic Compounds on CCl4-Induced Toxicity in Isolated Rat Hepatocytes
Authors: Añón M.T. , Ubeda A. , Alcaraz M.J.
Published: August 2018

The protective effects of a series of phenolic compounds, phenolic acids and flavonoids on the cytotoxicity of CCl4 in rat hepatocytes were studied. A number of flavones, 7,8-dihydroxyflavone, luteolin and hypolaetin-8-glucoside, flavonols, morin, quercetin, robinetin and gossypin, phenolic acids, gallic, caffeic and chlorogenic acids, as well as the flavane ( + )-catechin significantly inhibited alanine amine transferase (ALT) release. Catechol groups are determinant for the protective activity of flavonoids and cinnamic acid derivatives, as well as the resorcinol or pyrogallol moieties in the B ring of flavonoids. In benzoic acid derivatives a pyrogallol group is required. This feature is associated with the inhibition of ALT spontaneous release.
Dufour’s Gland Composition in the Desert Ant Cataglyphis: Species Specificity and Population Differences
Authors: Hefetz Abraham , Lenoir Alain
Published: August 2018

Dufour’s gland secretion of several species of the desert ant Cataglyphis from different geographical localities was analyzed. The secretions constituted mostly of alkanes ranging from undecane to nonadecane. Species specificity is expressed as variations in the major component as well as the relative intensities of the additional constituents. Phylogenetically related species that are allopatric exhibited similar secretory composition whereas their sympatric counterparts had disparate composition, suggesting that character displacement occurred. Analyses of colonies of C. cursor from different localities also showed divergence in their glandular composition.
Relative Affinities of Nucleotide Substrates for the Yeast tRNA Gene Transcription Complex
Authors: Szafranski Przemyslaw , Smagowicz W. Jerzy
Published: August 2018

Apparent Michaelis constants for nucleotides in transcription of yeast tRN Agene by hom ologous RNA polymerase III with auxiliary protein factors, were found to be remarkably higher in initiation than in elongation of RNA chain. This supports presumptions regarding topological similarities between catalytic centers of bacterial and eukaryotic RNA polymerases.
Mutations in the Subunit of Photosystem II and Resistance to the Phenol Type Herbicide Ioxynil in Synechocystis PCC 6714 and 6803
Authors: Perewoska I. , Vernotte C. , Picaud M. , Astier C.
Published: August 2018

Several herbicides block the photosystem II electron transfer because they compete with QB, the second stable electron acceptor of photosystem II for binding to the D1 subunit. We have previously isolated a mutant of Synechocystis 6714 in which Asn is replaced by Thr at position 266 of D1 (G. Ajlani, I. Meyer, C. Vernotte, and Astier, FEBS Lett. 246, 207-210 (1989)) and presenting resistance to ioxynil but not to DCMU . In this report we present selection, from this mutant, of a double mutant with an additional substitution at position 264 (Ser by Ala). The sensitivity of this mutant toward several herbicides is given and compared to those of the mutants having only one substitution at 266 and one substitution at 264. It was also compared to a mutant of Chlamydomonas having the same substitutions. This allows us to discuss the interaction of various herbicides with the D1 protein and to compare the herbicide binding niches of Chlamydomonas and Synechocystis.
The Effect of Resorcinolic Lipids on Phospholipid Hydrolysis by Phospholipase A2
Authors: Kozubek A.
Published: August 2018

The effects of resorcinolic lipids (5-n-alk(en)ylresorcinols) isolated from cereal grains on the phospholipase A2 catalyzed hydrolysis of phospholipid vesicles were examined. Studied compounds inhibited the apparent enzyme activity at the molar fraction in the membrane as low as 0.025, which is equivalent to the concentration of 3 μᴍ . This effect was visualized by dramatic increase (over ten-fold) of the latency period of the reaction progress. This makes resorcinolic lipids one of the most potent inhibitors of phospholipase A2 among already studied compounds. Highest inhibitory activities were shown for dienoic and monoenoic homologs of 17 carbon atoms in the aliphatic chain. Both saturation of the chain and the increase of its length reduced inhibitory properties of resorcinolic lipids. The data suggest that the compounds studied in this paper like other known amphiphilic inhibitors of phospholipase A2 owe most of their effects to the ability to modify the quality of the substrate interface. These are the alteration of the enzyme binding, velocity of the formation and redistribution of the products. However part of the effect seems to be attributed to direct interaction and modification of enzyme properties by alk(en)ylresorcinols.
A Myricetin Tetramethyl Ether from the Leaf and Stem Surfaces of Tillandsia usneoides
Authors: Wollenweber Eckhard , Mann Karin , Roitman James N.
Published: August 2018

Myricetin-3,7,3′,4′-tetramethyl ether has been isolated as an aglycone from the acetone wash of Tillandsia usneoides. It is thus shown to be deposited externally, on leaf and stem surfaces. We suggest that the previously reported lipophilic flavonoids from this and other species are also exudate constituents.
The Growth of Freshwater Green Algae in Weak Alternating Magnetic Fields of 7.8 Hz Frequency
Authors: Pazur Alexander , Scheer Hugo
Published: August 2018

Liquid cultures of Chlorella kessleri, Scenedesmus armatus and Chlamydomonas reinhardtii have been grown phototrophically in weak (0 .2 -2 G) alternating (7.8 Hz) magnetic fields. The data indicate, that the rate of cell division is larger at 0.2 than at 2 G, viz. that the higher fields have inhibitory effects on cell division and that there is possibly an optimum at ≈ 1 G. N o reliable effect is found on the pigment contents.
Purification of Antiviral Proteins with Ribosome-Inactivating Properties from Plants
Authors: Schönfelder Max , Janott Ute , Frötschl Roland , Mundry Karl-Wolfgang , Adam Günter
Published: August 2018

A generally applicable highly effective purification method for antiviral plant proteins, selective for those with ribosome-inactivating properties, was developed. It involved affinity chromatography on Cibacron Blue Sepharose of the extracted plant sap after acid-ethanol precipitation and finally cation exchange chromatography on Mono S (Pharmacia). After the second chromatography step electrophoretically pure proteins from the four plant species, Chenopodium amaranticolor, Dianthus barbatus, Phytolacca americana and Spinacia oleracea, were obtained. These proteins inhibited infection of test plants with alfalfa mosaic virus and in vitro translation of TMV-RNA. The apparent molecular weights of the purified proteins were determined by SDS polyacrylamide gel electrophoresis as: 29 kDa for C. amaranticolor, 33 kDa for D. barbatus, 29 kDa for P. americana and 36 kDa for S. oleracea. Comparisons of the proteins by indirect ELISA and by Western blotting with polyclonal antisera from rabbits revealed that all four proteins were serologically related but not identical. In addition all four proteins were found to be glycosylated.
Notes: Exudate Flavonoids of Some Salvia and a Trichostema Species
Authors: Wollenweber Eckhard , Dörr Marion , Rustaiyan Abdolhossein , Roitman James N. , Graven Earl H.
Published: August 2018

Seven species of Salvia and one species of Trichostema were analyzed for their exudate flavonoids. They were found to exhibit flavonoid aglycones in various numbers and different patterns. Most of these are flavones, in which 6-methoxy-substituted compounds predominate.
7-O-Methyl-luteone Metabolism in Botrytis cinerea: Identification of the Epoxy-Intermediate and Absolute Configuration of the Pyrano-isoflavone Metabolite
Authors: Tahara Satoshi , Saitoh Fumihiko , Mizutani Junya
Published: August 2018

7-O-Methyl-luteone was metabolized in a buffer solution by resting cells of Botrytis cinerea which is known as a fungus detoxifying prenylated isoflavones into further oxygenated metabolites, and we could isolate an unstable epoxy-intermediate. The epoxy-intermediate was easily cyclized under acidic conditions to yield the corresponding isoflavone with a hydroxychroman part structure (= dihydropyrano-isoflavone). The optically active (dextrorotatory) dihydropyrano-isoflavone metabolite was derivatized into the [R]-a-methoxy-a-trifluoromethyl- phenylacetic acid ester and its absolute configuration [S] was unambiguously elucidated by the modified Mosher’s method.
The Effect of Neighboring Bases on Miscoding Properties of N2,3-Ethenoguanine
Authors: Mroczkowska Małgorzata M. , Kuśmierek Jarosław T.
Published: August 2018

The miscoding potential of N2,3-ethenoguanine (∈G), one of the carcinogen vinyl chloride adducts to DNA bases, has been examined by copying of poly (A, ∈G ) templates with DNA-dependent RNA polymerase and reverse transcriptase. In contrast to the results previously obtained with poly (C, ∈G) templates where ∈G acts as G and A, in poly (A, ∈G) templates ∈G acts alm ost exclusively as A. These results suggest that mutagenic potential of ∈G in vivo can depend on the nature of neighboring bases.
Glycogen Synthesis in Rat Liver from a Pool of Free Glucose
Authors: Schimassek H. , Meißner Ingrid
Published: August 2018

Glycogen synthesis in isolated perfused livers or livers of anesthetized rats (in situ), was studied using radioactively labelled fructose, lactate, and inositol as substrates. The specific radioactivity of glucose and glycogen was measured at various times and compared with that of some intermediates.

The results suggest that liver glycogen is formed from the pool of free glucose which in turn is fed by the so-called “direct and indirect pathway” of glycogen synthesis. This points to an important role of glucose-6-phosphatase, an enzyme complex subject to regulation by glucocorticoids, well known promoters of hepatic glycogen synthesis.
Two Different Bump Types of the Ventral Photoreceptor of Limulus
Authors: Reuß Helmut , Stieve Hennig
Published: August 2018

The elementary responses, the “bumps”, of the ventral photoreceptor of Limulus polyphemus were measured under voltage clamp conditions. We observed a type of bump which differs in size and time parameters from the “standard” bumps described previously. The average value of the amplitude of these “small, slow” bumps is about 20-fold smaller than that of the standard bumps (about 1 nA) and the average latency is about 25% longer. The duration of these bumps is 2 -5 -fold longer than that of a standard bump with the same amplitude. The small, slow bumps are probably light-induced and arise with about the same frequency after a light flash as standard bumps. The different kinetics of the two bump types can be explained by the assumption that the transduction chain branches into at least two pathways.
Pheromones, 88 [1]. Sex Pheromone Components of Female Euzophera punicaella M. (Lepidoptera, Pyralidae)
Authors: Bestmann H. J. , Kern F. , Melikyan G. G. , Schäfer D. , Vostrowsky O. , Babayan E. V. , Badanyan Sh. O.
Published: August 2018

By means of GC, GC-MS and GC-combined EAG recordings (9Z,12E)-9,12-tetradecadien-1-ol (1) and (9Z,12E)-9,12-tetradecadienyl acetate (2) in a ratio of 4:1 were identified as the pheromone components of the female pyralid moth Euzophera punicaella M. originating from Armenia. Determination of EAG activity with male moth antennae and synthetic test chemicals revealed best responses with a mixture of both compounds.
Segregation of Activity Profile in Benzimidazoles: Effect of Spacers at 5(6)-Position of Methyl Benzimidazole-2-carbamates [1]
Authors: Agarwal Shiv K. , Sharma Satyavan , Bhaduri A. P. , Katiyar J. C. , Chatterjee R. K.
Published: August 2018

The design and synthesis of a series of methyl 5(6)-substituted benzimidazole-2-carbamates as possible anthelmintics have been described. A rational analysis of the structural parameters which segregate the activity of resulting benzimidazole-2-carbamates against enteric and tissue dwelling helminths is presented. The influence of single and multiple spacers, which link the pharmacophores at 5(6)-position of benzimidazole-2-carbamate, on the activity against Ancylostoma ceylanicum (hookworm), Syphacia obvelata (pinworm), Hymenolepis nana (tapeworm), Litomosoides carinii and Acanthocheilonema viteae (filarial worm) has been presented. This analysis indicates that for activity against intestinal helminth the presence of one spacer holding the pharmacophore approximately 3 Å apart from the parent nucleus is usually preferred. While for activity against tissue dwelling parasite, the repetition of the benzimidazole-2-carbamate nucleus joined together through the 5,5′-position with one spacer kept apart by distance of 3 Å unit is usually desired.
Bisbibenzyl Formation in Aseptic Cultures of Marchantia polymorpha L
Authors: Adam Klaus-Peter , Becker Hans
Published: August 2018

Three new aseptic cultures of Marchantia polymorpha from different collecting sites have been induced from the gametophytes. The formation of bisbibenzyls in differentiated cultures and cell suspension cultures was investigated. We observed that the production of the main bisbibenzyl, Marchantin A was induced by lack of nitrate and the addition of cupric sulfate to the medium. The comparison of bisbibenzyl patterns in three different cultures suggest the existence of chemical races of M. polymorpha. Bisbibenzyl patterns in differentiated cultures and cell suspension cultures appeared to be similar.
Transport of Oxidized Glutathione into Barley Vacuoles: Evidence for the Involvement of the Glutathione-S-Conjugate ATPase
Authors: Tommasini Roberto , Martinoia Enrico , Grill Erwin , Dietz Karl-Josef , Amrhein Nikolaus
Published: August 2018

Glutathione in its oxidized form (GSSG) is rapidly taken up into isolated barley vacuoles, while uptake of reduced glutathione (GSH) is only marginal. GSSG transport is strictly ATP-dependent and is a saturable process (Km 0.4 to 0.6 mм). Uptake is inhibited by vanadate, but not by bafilomycin, a specific inhibitor of the vacuolar H +-ATPase. The observation that i) the non-hydrolysable ATP analogue adenylylim idodiphosphate does not stimulate, but rather inhibits the ATP-dependent uptake of GSSG and ii) that a four-fold accumulation of GSSG is observed in the presence of bafilomycin, suggests that GSSG is transported into the vacuole by a primary active process similar to that of glutathione S-conjugates (E. Martinoia, E. Grill, R. Tommasini, K. Kreuz, N. Amrhein, Nature 364, 247-249 (1993)). U ptake of GSSG is competitively inhibited by the glutathione S-conjugate of the herbicide m etolachlor (Ki 80 μм), indicating that transport of GSSG is mediated by the glutathione S-conjugate ATPase.
Cu(II)-Induced Oxidation of Catechols, Ascorbate and o-Phenylenediamine is Promoted by DNA
Authors: Prütz Walter A.
Published: August 2018

Cu(II)-Induced oxidation of catechols (dopa, dopamine and epinephrine) to yield indolic aminochromes is speeded up by at least two orders of magnitude upon addition of DNA. This effect was observed both in aerobic and anaerobic solutions, indicating that it is not due to the reductive activation of oxygen with formation of O2
·- and H2O2 as oxidant. It is suggested that the unfavourable redox equilibrium of the catechol-Cu(II) complex, ROH-Cu(II) ⇄ Cu(I) + RO· + H+, to yield Cu(I) and semiquinone, is efficiently driven to the right by DNA due to formation of the strong DNA-Cu(I) complex, for which a stability constant of K ≈ 2×109 м-1 has been estimated previously. Absorbance changes characteristic to the formation of DNA-Cu(I) appear in fact concomitantly with the 480 nm absorption of aminochrome, derived from the semiquinone RO·. Cu(II)-Induced oxidation of ascorbate and o-phenylenediamine (leading to 2,3-diaminophenazine) was also speeded up by almost two orders of magnitude in presence of DNA. The observed activation of redox reactions of copper in the vicinity of DNA may have important implications with respect to the toxicological properties of certain bioreductive endogenous and xenobiotic compounds.
Seasonal Changes in the Activities of Apoplastic, Cytoplasmic, Ionically and Covalently Bound Isoperoxidases from Norway Spruce (Picea abies (L.) Karst.) Needles: A Comparison between Three Collection Sites with Different Ambient Ozone Concentrations
Authors: Ikemeyer Dietmar , Büttner Peter , Barz Wolfgang
Published: August 2018

Apoplastic, cytoplasmic, ionically and covalently bound isoperoxidases were investigated from needles of Norway spruce (Picea abies (L.) Karst.) and a pronounced genetic variability of the isoenzyme pattern was found. The enzymatic activity of each group of isoperoxidases was determined between November 1989 to November 1990 from needles of three locations (Velmerstot, Glindfeld, Haltern) with different ozone concentrations. Apoplastic peroxidases of needles from trees grown in Velmerstot and Glindfeld showed up to two-fold higher activities than the same group of peroxidases from Haltern. Based on the recorded increased ozone concentrations in Velmerstot and Glindfeld a positive correlation between the activity of the apoplastic peroxidases and ambient ozone concentrations at the different locations could be demonstrated. A putative role of the apoplastic peroxidases as a bioindicator for air pollutants is discussed.
X-Ray Studies on Phospholipid Bilayers. XIV. Interactions with the Antiarrhytmic Asocainol
Authors: Suwalsky M. , Sánchez I. , Neira F.
Published: August 2018

Asocainol (ASOC) belongs to class I of the antiarrhytmic drugs, i.e., those that exert their action at the level of the sodium channels of the myocardial cell membrane. It has been suggested that their molecular mechanism of action might be through nonspecific interactions with phospholipids that surround the channel proteins. In order to test this hypothesis, ASOC was made to interact with two multibilayer systems, one built-up of dimyristoylphosphatidylcholine (DMPC) and the other of dimyristoylphosphatidylethanolamine (DMPE). These are the type of lipids that are respectively found in the outer and inner monolayers of human erythrocytes. The experiments were carried out in a hydrophobic as well as in a hydrophilic medium below the phospholipid main transition temperatures. The perturbing effect of ASOC upon the bilayer structures was determined by X-ray diffraction. It was found that ASOC was able to fluidize DMPC in both media but not to DMPE.
Antibiotic and Cytotoxic Activity of Brominated Compounds from the Marine Sponge Verongia aerophoba
Authors: Teeyapant R. , Woerdenbag H. J. , Kreis P. , Hacker J. , Wray V. , Witte L. , Proksch P.
Published: August 2018

Analysis of the marine sponge Verongia aerophoba from the Canary Islands afforded eight brominated secondary metabolites including the small molecular weight compounds aeroplysinin-1 (5) and the dienone (7) which were previously shown to arise by enzymatically catalyzed degradation of aerophobin-2 (4) and isofistularin-3 (1) following breakdown of the cellular compartmentation of the sponge. All compounds were identified from their NMR and mass spectra. Aeroplysinin-1 as well as dienone which arise from isofistularin-3 or aeropho­ bin-2 by biotransformation within the sponge showed a significantly higher antibiotic as well as cytotoxic activity than their biogenetic precursors. Antibiotic activity was studied with re­spect to several gram-positive and gram-negative bacteria including B. subtilis, S. aureus and E. coli. The MICs (MBCs) of aeroplysinin-1 (5) and the dienone (7) varied between 12.5-25 (50-100) μg/ml respectively. Cytotoxicity was tested in vitro towards HeLa cells, a human cervix uteri tumour cell line. Aeroplysinin-1 (5) and the dienone (7) displayed pronounced cytotoxic activity with IC50s of 3.0 and 3.2 μм respectively. A five-fold increase in cytotoxicity was observed after O-acetylation of the dienone (7). The IC50 of the dienone O-acetate (0.6 μм) was comparable to that of the clinically used anticancer drug cisplatin (0.7 μм).
Flavonoid-Aglyka als Drüsenprodukte der Moosrose (Rosa centifolica cv. muscosa) und der Japanischen Weinbeere (Rubus phoenicolasius) / Flavonoid Aglycones as Glandular Products in Rosa centifolia cv. muscosa and in Rubus phoenicolasius
Authors: Wollenweber Eckhard , Dörr Marion , Armbruster Sylvia
Published: August 2018

The sticky lipophilic exudates produced by glands on inflorescences of Rosa centifolia cv. muscosa and Rubus phoenicolasius contain flavonoid aglycones. Ten different flavonoids were identified from Rosa centifolia cv. muscosa, including several flavones with 6,8 -methoxy substitution. In Rubus phoenicolasius, the major flavonoids are methyl ethers of quercetin.