bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of γ-Hexachlorocyclohexane (Lindane) on the Activities of Liver Lipogenic Enzymes and on Serum Lipids in Rats
Authors: Boll Meinrad , Weber Lutz W. D. , Stampfl Andreas
Published: August 2018

The effect of dietary γ-hexachlorocyclohexane (lindane) (50 -350 ppm, 0.17-1.19 μmol/kg chow) on the activity of enzymes of lipogenesis, viz., fatty acid synthase (FAS; EC 2.3.1.85), citrate cleavage enzyme (CCE; EC 4.1.3.8), malic enzyme (ME; EC 1.1.1.40), glucose-6-phosphate dehydrogenase (G 6 PDH; EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (PGDH; EC 1.1.1.44), and on serum lipid levels, was investigated in livers of 35-day-old male Wistar rats.

Lindane (150 ppm) caused a substantial decline of enzyme activities within the first 24 h of treatment. The decrease was transient, however, and enzyme activities subsequently recov­ered despite continuation of lindane feeding. The recovery of enzyme activities was compara­ tively fast in the case of ME, G 6 PDH and PGDH, but very slow with FAS and CCE.

Activities of lipogenic enzymes decrease when animals are starved, and increase much beyond prestarvation levels upon subsequent refeeding. Lindane in the refeeding diet blunted this overshoot of FAS and CCE activities in a dose-dependent manner. In contrast, activities of ME, G 6 PD H and PGDH responded to low dietary lindane concentrations with a substantial stimulation of the increase of activity, whereas at high lindane concentrations the overshoot was inhibited.

According to their responses to lindane exposure, liver lipogenic enzymes could be grouped into 2 categories with FAS and CCE representing one and ME, G 6 PDH and PGDH representing the other group.

Polychlorinated biphenyls (PCBs) in the diet caused basically opposite changes of the activities of the lipogenic enzymes. Co-administration of lindane and PCBs resulted in an apparent cancellation of effects, suggesting that lindane and PCBs affect fatty acid synthesis at opposite points.

Levels of the serum triglycerides were increased significantly as a result of lindane feeding, while serum cholesterol and phospholipid levels were only slightly elevated. The increase of serum triglyceride levels that is routinely observed after refeeding of starved animals was stimulated even more by low concentrations of lindane in the refeeding diet, but inhibited by high concentrations.
Phylogeny of Old and New World Vultures (Aves: Accipitridae and Cathartidae) Inferred from Nucleotide Sequences of the Mitochondrial Cytochrome b Gene
Authors: Wink Michael
Published: August 2018

The molecular phylogeny of 11 Old World and 5 New World vultures was inferred from nucleotide sequences of the mitochondrial cytochrome b (cyt b) gene. According to this analysis carrion-feeding has evolved independently at least three times during evolution: 1.) In the New World vultures, which are clearly separated from vultures of the family Accipitridae; 2.) in the Neophron-Gypaetus clade which is positioned at the base of the Accipitrid tree and 3.) in the Gyps-Aegypius-complex which encloses the largest group of Old World vultures. Thus the genetic data clearly show that the carrion-feeding lifestyles and associated morphologies shared by New and Old World vultures are rather based on convergence than on close genetic relatedness. Employing the cyt b sequences of 12 other members of the Falconiformes and 10 members of the Ciconiiformes (sensu Sibley and Monroe, 1990) the phylogenetic relationship between the three clades of vultures and these other taxa was assessed. New World Vultures appear to share distant ancestry with storks but a close relationship is unlikely.
Structure and Characterization of Isopyoverdin from Pseudomonas putida BTP1 and Its Relation to the Biogenetic Pathway Leading to Pyoverdins
Authors: Jacques Ph. , Ongena M. , Gwose I. , Seinsche D. , Schröder H. , Delfosse Ph. , Thonart Ph. , Taraz K. , Budzikiewicz H.
Published: August 2018

Pyoverdin type siderophores produced by six fluorescent Pseudomonas strains isolated from different rhizospheres were purified and characterized. The purified ferri-pyoverdins were tested for their ability to promote the growth of other strains grown under iron deficiency conditions. Only the one obtained from Pseudomonas putida BTP1 did not act as a growth promoter.

The structure of the BTP1 siderophore was elucidated by spectroscopic methods and degradation studies. It turned out that it contains a chromophore which differs from the one typical for pyoverdins insofar as it carries the carboxyl group in 3- rather than in 1-position ((3S)-5-amino-1,2-dihydro-8,9-dihydroxy-3 H -pyrimido[1,2 a]quinoline-3-carboxylic acid). The amino group of the chromophore is substituted with the 5-carboxyl group of ʟ-glutamic acid and its carboxyl group with the N -terminus of the peptide ʟ -A sp -ʟ -A la-ʟ -Asp - ᴅ-N5- Ac - N5- OH - Orn - ʟ - Ser - ʟ - ᴄ - N5- OH - Orn . This isopyoverdin fits into the biogenetic scheme which postulates ferribactins as the precursors of pyoverdins
Kinetic Characteristics, Substrate Specificity and Catalytic Properties of Phosphoserine Aminotransferase from the Green Alga Scenedesmus obliquus, Mutant C-2A
Authors: Stolz M. , Dörnemann D.
Published: August 2018

Phosphoserine am inotransferase (EC 2.6.1.52) has been purified from Scenedesmus

obliquus. mutant C -2A′, as reported previously (Stolz and Dörnemann, 1994). The current studies on its catalytic properties, involving initial reaction velocities as a function of the phosphoserine concentration at various fixed concentrations of 2-oxoglutarate as aminoacceptor, indicate a bi-bi ping pong mechanism . The application of a variety of substrate analogues of phosphoserine revealed no significant metabolisation of these com pounds and thus a considerable specificity of the enzyme. 4,5-dioxovalerate with glutamate as am inodonor is effective as competitive substrate to phosphohydroxypyruvate in the forward reaction and yields 5-am inolevulinate.

4.5-Dioxovalerate and glutam ate-1-semialdehyde can both serve as competitive aminoacceptor in the reverse reaction with phosphoserine and as substrate with 2-oxoglutarate as am inoacceptor. Comparison of the phosphoserine transamination with the transamination of 4,5-dioxovalerate revealed for both reactions a pH -optim um of 6 .8 -7 .0 in Mes/Bis-Trisbuffer. How ever, the Km-values and the Vmax for phosphoserine and 2-oxoglutarate on the one side, and 4,5-dioxovalerate and glutamate on the other were found to differ by orders of magnitude
Fusiogenic Activity of Natural Amphiphiles, 5-n-Alkylresorcinols in a Yeast Protoplast System
Authors: Kozubek Arkadiusz , Skała Jacek
Published: August 2018

Two homologues of cereal grain resorcinolic lipids, 5-n-heptadecylresorcinol and 5-n-hepta-decenylresorcinol studied in the system employing yeast cell protoplasts showed marked fusiogenic activity. The frequency of hybrid formation induced by studied amphiphiles was significantly higher than that obtained with the use of 40% (w/v) polyethylene glycol 4000. The resorcinolic lipids as fusion-inducing agents did no affect regeneration of the cellular wall. The fusiogenic activity of resorcinolic lipids lost when calcium ions were absent in the medium. Fusiogenic activity of studied amphiphiles is related to their ability to induce non­ bilayer structures within the cellular membranes.
Identification of Amino Acids in Brazilian Propolis
Authors: Marcucci M. C. , Camargo F. A. de , Lopes C. M. A.
Published: August 2018

Amino acids of propolis samples from different origins were analysed and quantified. Seven of them presented almost the same percentage in all samples, indicating that bees may have obtained amino acids from three sources: plants, pollen contamination and from their own metabolism. The regeneration properties of propolis in relation to the presence of some amino acids are discussed.
Azoverdin -an Isopyoverdin
Authors: Michalke R , Taraz K , Budzikiewiez H
Published: August 2018

For azoverdin, the siderophore of Azomonas macrocytogenes ATCC 12334, a pyoverdintype structure has been suggested. We now present evidence that it is actually an isopyoverdin. Also the sequence of the peptide chain has to be revised. Azoverdin comprises, therefore, the chromophore (3S)-5-amino-1,2-dihydro-8,9-dihydroxy-3H -pyrimido[1,2a]quinoline- 3-carboxylic acid whose amino group is bound to a succinamide residue while the carboxyl group is attached to the N -terminus of L-Hse-[2-(R-1-amino-3-hydroxypropyl)-3,4,5,6- tetrahydropyrimidine-65-carboxylic acid]-N5-acetyl-N5,-hydroxy-ᴅ-Orn-ᴅ-Ser-N5-acetyl-N5- hydroxy-ʟ-Orn. In addition to azoverdin congeners with succinic acid (azoverdin A ) and with ʟ-Glu (azoverdin G ), resp., instead of the succinamide side chain could be isolated.
Quantitative Changes of the Lipid and Fatty Acid Composition of Leaves of Aleurites montana as a Consequence of Growth under 700 ppm CO2 in the Atmosphere
Authors: He P , Radunz A , Bader K. P , Schmid G. H
Published: August 2018

Leaf lipids of Aleurites plants that were cultivated for 5 months in air containing 700 ppm CO2, were compared to those of control plants cultivated at 350 ppm CO2. The content of ether soluble lipids referred to dry matter is the same in CO2-and control plants. The comparison of lipids analyzed as the pigments chlorophyll and carotenoids, phospholipids and glycolipids shows that the ratio of phospholipids and glycolipids is slightly shifted in favor of phospholipids in CO2-plants. Thus, within the group of phospholipids, phosphatidylglycerol and phosphatidylinositol occur in higher concentrations in CO2-plants.

Although the differences in the lipid content appear moderate in CO2-and control plants, it is the saturation degree of fatty acids that differs substantially. The fatty acids of CO2-plants contain according to the higher phospholipid content approx. 5% more saturated fatty acids. Stearic acid is three-fold increased. Whereas in the phospholipid fraction saturated fatty acids comprise one half of all fatty acids, the unsaturated fatty acids make up for 80 to 90% in the glycolipid fraction. In CO2-plants not only in the phospholipid fraction but also in the glycolipid fraction saturated fatty acids occur in a higher portion. This means that not only in the cell membrane of CO2-plants but also in the thylakoid membrane the fluidity is decreased. Also in the wax-fraction long-chained carbonic acids with 20 -26 carbon atoms occur. As the portion of these carbonic acids is twice as high in CO2-plants, it is concluded that a stronger formation of the wax layers exists in CO2-plants.

By means of Western blotting and by the use of lipid and carotenoid antisera the binding of lipids onto proteins of photosystem II and photosystem I was analyzed. It is seen that besides the major amount of lipids which build up the thylakoid membrane, some lipids are also bound to membrane peptides. Whereas monogalactolipid is bound to the LHCP-complex peptides, to the OEC1 -peptide and the 43 and 47 kDa chlorophyll binding peptides, the anionic lipids sulfoquinovosyldiglyceride and phosphatidylglycerol and digalactolipid are bound to the core peptides of PS II and PS I. β-carotene and the xanthophylls were found to be bound to the core peptides and β-carotene and violaxanthin were also bound to the light-harvesting pigment complex.
Conjugative Transfer and Expression of Genes Coding for Periplasmic Nitrate Reductase in the Purple Bacterium Rhodospirillum rubrum
Authors: Klemme Jobst-Heinrich , Kaminski Annette , Hougardy Angela
Published: August 2018

Plasmid pFR400, a derivative of the vector plasmid pPHU231 containing the structural genes of the periplasmic nitrate reductase (nap genes) of Rhodobacter sphaeroides DSM 158 (F. Reyes et al., Molec. Microbiol. 19, 1307-1318 [1996]) was transferred by conjugative mating to a streptomycin-resistant strain of the nitrate reductase-negative nonsulfur purple bacterium Rhodospirillum rubrum S1. Transconjugant cells of the latter bacterium, identified by their resistance to streptomycin and tetracycline and by their plasmid pattern, contained an active nitrate reductase which, like other periplasmic bacterial nitrate reductases, was not repressed by ammonium.
Trehalose Protects Yeast Pyrophosphatase against Structural and Functional Damage Induced by Guanidinium Chloride
Authors: Sola-Penna Mauro , Meyer-Fernandes José Roberto
Published: August 2018

Trehalose is accumulated at very high concentrations in yeasts when this organism is sub­ mitted to a stress condition. This report approaches the question on the protective effect of trehalose and its degradation product, glucose, against structural and functional damage promoted by guanidinium on yeast cytosolic pyrophosphatase. Here it is shown that both, 1 ᴍ trehalose or 2 ᴍ glucose, are able to attenuate at almost the same extent the conforma­ tional changes promoted by guanidinium chloride on the pyrophosphatase structure. On the other hand, while 1 m trehalose increases 3.8 times the Ki (from 0.15 to 0.57 ᴍ) for guanidi­ nium chloride inhibition of pyrophosphatase activity, 2 m glucose did not even duplicate this parameter (from 0.15 to 0.25 ᴍ). These data support evidences for a functional reason for the accumulation by yeasts of trehalose, and not other compound, during stress conditions.
Indoid Glucosides from Four Balkan Endemics of the Galium incurvum Group (Rubiaceae)
Authors: Mitova Maja Iv. , Handjieva Nedjalka V. , Anchev Mincho E. , Popov Simeon S.
Published: August 2018

The Balkan endemics G. mirum, Galium macedonicum, G. rhodopeum and G. aegeum, from the G. incurvum group, were screened for iridoid glucosides. Eleven known iridoid glucosides were isolated, identified and analysed for the first time in the investigated plants.

The main components appeared to be asperuloside and/or the non-acetylated iridoid acids -deacetylasperulosidic acid, scandoside, monotropein. Phylogenetic relationships are discussed.
Quinolizidine Alkaloid Profiles of Retama raetam, R. sphaerocarpa and R. monosperma
Authors: El-Shazly A. , Ateya A.-M. , Witte L. , Wink M.
Published: August 2018

About 28 quinolizidine alkaloids and the dipiperidine alkaloids am modendrine, dehydroammodendrine and N -formylammodendrine were identified in the alkaloidal extracts of Retama raetam, Retama sphaerocarpa and Retama monosperma by capillary GLC and GLCMS. Alkaloid profiles of the three Retama species with a Mediterranean distribution are more similar than alkaloid patterns of different organs of the same plant. Whereas sparteine and retamine are the major components of stems, lupanine, retam ine, N-methylcytisine and cytisine dominate in flowers and pods, and cytisine in seeds indicating a high degree of organ specificity of alkaloid storage.
Isomerization of Peroxidizing Thiadiazolidine Herbicides Is Catalyzed by Glutathione S-Transferase
Authors: Nicolaus Beate , Sato Yukiharu , Wakabayashi Ko , Böger Peter
Published: August 2018

Thiadiazolidine-converting activity (isomerase), detected in a 45-75% ammonium sulfate precipitate from corn seedlings extracts, was purified by chromatography on hydroxyapatite and by anion exchange on Mono Q Sepharose. Two fractions 1 and 2 with isomerase activity were separated on Mono Q by combination of a stepwise elution and continuous salt gradient; fraction 2 eluting at higher salt concentrations was found the most active. Total activity could be enhanced by treatment of seedlings with naphthalic anhydride. Both fractions containing isomerase activity were further purified by glutathione-(GSH) agarose affinity chromatography and characterized by their specificity for different thiadiazolidines. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel filtration revealed that the isomerase of fraction 2 consists either of a homodimer or a heterodimer of two proteins with apparent molecular weights of 28 and 31 kDa, respectively. The protein pattern as well as the strict dependence of activity on thiol groups (GSH or dithiothreitol) suggested a glutathione Stransferase (GST) catalyzing the thiadiazolidine conversion. Further evidence was obtained by measuring reactions specific for GSTs in both purified fractions, namely the conjugating activity for l-chloro-2,4-dinitrobenzene (CDNB ). atrazine and metazachlor. While no atrazine turnover was found, metazachlor and CDNB conjugation occurred rapidly. Both fractions differed in their activities to several GST substrates with fraction 2 being more effective in metazachlor but less active in C DN B conjugation. Inhibitors specific for GST-catalyzed reactions also inhibited thiadiazolidine conversion confirming that isomerizing activity is attributed to a GST form. We conclude that GST isoforms with different affinities towards thiadiazolidines have been isolated. CDNB activity, molecular weight, the protein pattern on SDS-PAGE as well as the amino acid sequence of one of its polypeptides suggest that fraction 1, less active in thiadiazolidine isomerization, is identical to GST I. The second peptide of this fraction was resistant to Edman degradation probably due to N-terminal blockage. The properties of the high isomerase activity found in fraction 2 are in agreement with characteristics of a GST previously termed as isoform II.
Characterisation of a Neutral Protease Produced by Micrococcus luteus
Authors: Ilori M.O. , Amund O.O. , Omidiji O.
Published: August 2018

A proteolytic enzyme produced by a cassava-ferment­ing strain of Micrococcus luteus was extracted and puri­fied 50-fold by gel filtration and ion exchange chromatography.

The optimum pH for the enzyme was 7.0, the optimum temperature 25 °C, the apparent molecular weight 42 kDa and the Km value, 0.45 mg ml-1 with casein as substrate. The enzyme was stimulated by Ca2+ and Mg2+ but inhibited by Zn2+ and Co2+ ions. Other inhibitors were EDTA, KCN, citric acid and L-cysteine indicating the enzyme to be a metalloprotease.
The Revolution in Insect Neuropeptides Illustrated by the Adipokinetic Hormone/Red Pigment-Concentrating Hormone Family of Peptides
Authors: Gäde Gerd
Published: August 2018

The last decade has seen a surge in the knowledge on primary structures of insect neuropeptides. Particularly successful were isolations and sequence determinations of more than 30 members of the adipokinetic hormone/red pigment-concentrating hormone (AKH/RPCH) family of peptides. This brief overview describes the techniques used to obtain data on purification and structure such as high performance liquid chromatography, Edman sequencing and mass spectrometry. Moreover, a short account on the precursors and on the multiple functions of the peptides of the AKH/RPCH family in various crustacean and insect species is given
Phenolic Constituents of Galactites tomentosa (Asteraceae)
Authors: Bäumer Dietrich , Ruppel Hans Georg
Published: August 2018

The Asteracea Galactites tomentosa. known as a plant causing allergic contact reactions, was investigated for new constituents in leaves and stems. Chlorogenic acid and 3,5-dicaffeoylquinic acid could be detected by HPLC in tissues and trichome preparations as well
A New Lignan from Brazilian Propolis
Authors: Bankova V. , Nikolova N. , Marcucci M.
Published: August 2018

The known flavonoid kaempferid 4 and a new benzofurane lignan 1 were isolated from Brazilian propolis. The new lignan is a suitable taxonomic marker and gives new possibilities for identification of propolis plant sources in the tropical regions
Cell Surface Glycoconjugates of Euglena gracilis (Euglenozoa): Modifications under Potassium and Magnesium Deficiency
Authors: Preisfeld Angelika , Scholten-Beck Gabriele , Ruppel Hans Georg
Published: August 2018

Biochemical and ultrastructural examinations on the pellicle of autotrophically grown Eu­glena gracilis were carried out after three days under potassium and magnesium deficiency. Cell-surface changes were detected by lectin assay. Compared to cells grown in complete medium, deficient cells become larger in shape, accompanied by rising carbohydrate, chloro­phyll and protein content, bind more and other lectin molecules: an increase of mainly galactose and N-acetylgalactosamine receptors was observed. Investigations with the mucilage stains alcian blue and ruthenium red indicated that mucilaginous material is released under deficient conditions, whereas the control cells show a strong precipitate of these stains well inside the cells beneath the pellicle.
Cytotoxicity and Antitumor Activity of Platinum(II) Complexes of Aromatic and Cycloalkanecarboxylic Acid Hydrazides
Authors: Kushev Daniel N. , Spassovska Nadejda C. , Taxirov Svetoslav I. , Grancharov Konstantin C.
Published: August 2018

New platinum(II) complexes of cyclohexanecarboxylic acid hydrazide (chcah) were synthesized and characterized by elemental analysis, IR. and 1H NMR spectra. Their inhibitory effects on cell growth and macromolecular synthesis of Friend leukemia cells in culture as well as the in vivo antitumor activity towards L1210 leukemia in mice were compared with those of complexes containing differently substituted aromatic acid hydrazides. Some of the complexes exhibited antineoplastic activity. No correlation between the in vitro cytotoxicity and the in vivo antitumor activity was found. However, there was a relationship between the in vitro macromolecular synthesis inhibition profile and the in vivo antineoplastic effect, similar to that of cisplatin. On the other hand, only agents containing one ammine ligand were active in vivo. The substitution of the aromatic ring by a cycloalkane residue increased significantly the antitumor effect, with [Pt(NH3)(chcah)Cl2] being the most active compound in this study.
Folding of the SPKK Rich Peptide in the Presence of the Octa-Oligonucleotide
Authors: Zubrzycki Igor Z. , Bohm Lothar
Published: August 2018

The nucleosome contains of 200 base pairs of DNA complexed with four core histone complex: H2A , H2B, H3, and H4. The fifth histone species, the H1 histone, interacts with linker DNA connecting neighbouring nucleosomes. We have studied the influence of the phosphorylation on the interactions of a repeating unit 15 residues long, containing the SPKK motif, the motif thought to induce turn along peptides sequences, enclosed within the trout testis H1 C-terminal domain with octanucleotide by means of the thermal denaturation and CD technique. The results indicate that the peptide preferentially binds to a single stranded oligonucleotide. It has been shown further that there is no β structure present but a distorted helical structure has been detected.
Two Ways of Hydrogen Peroxide Formation in the Oxidative Inactivation of Cyanobacterial Glutamine Synthetase
Authors: Martin Gottfried , Böger Peter
Published: August 2018

Using crude extracts from the cyanobacterium Anabaena variabilis glutamine synthetase (GS) activity was rapidly irreversibly reduced to about 60% during dark incubation ("sponta­neous GS inactivation"). An additional decrease was observed by the addition of ammonia in the light ("ammonia-mediated inactivation"). Both effects were prevented by EDTA, MnCl2 or catalase indicative of the involvement of H202. This is a key intermediate in oxidative enzyme inactivation. In both spontaneous and am monia-mediated GS inactivation H202 is produced in different ways. Spontaneous inactivation is prevented by depletion of reduced pyridine nucleotides which apparently donate electrons to produce H202. Fractionation of the crude extract showed that the light-enhanced GS inactivation by ammonia required the presence of thylakoid membranes. The photosynthesis inhibitor DCMU decreased GS inactivation by ammonia. For the inactivation in the light apparently H202 is produced from super­ oxide during photosynthetic electron transport.
Antioxidant Activity of Flavones from Scutellaria baicalensis in Lecithin Liposomes
Authors: Gabrielska Janina , Oszmiańsk Jan , Żyłka Romuald , Komorowska Małgorzata
Published: August 2018

Trihydroxyflavones of Scutellaria baicalensis, Antioxidant Activity, Liposome, Peroxidation, MDA The antioxidant effect of a trihydroxyflavone extract from Scutellaria baicalensis on oxida­ tion induced by ultraviolet light, was studied with phosphatidylcholine liposome membrane. Also, as standards, the antioxidative activity of baicalin, wogonin, baicalein and butylated hydroxytoluene (BHT) was investigated. Comparison of the protective effects of thecom­pounds studied against photoinduced lipid peroxidation in lecithin liposome membranes showed that: (1) the inhibitory effect of those compounds (at 1.2 mol% antioxidant content in liposomes) on TBA reactive materials from lipid peroxidation decreased in the order of baicalin > BHT ≅ Scutellaria baicalensis. These were found much greater than wogonin and baicalein; (2) the depressed effect of those compounds (at 1.1 mol% compounds content in liposomes) on the production of conjugated dienes (proportional to oxidation index) could be classified as follows: Scutellaria baicalensis ≅ baicalin > BHT, these three were found more active much greather than baicalein and wogonin. Results obtained by ESR measure­ment confirm that Scutellaria baicalensis extract and the BHT compound significantly de­ pressed the effect of liposome oxidation. It was found that the new trihydroxyflavones of Scutellaria baicalensis, ensured a very satisfactory concentration-dependent protection of the liposome membrane against UV-induced oxidation. These findings suggest that some of the beneficial effects of the extract of the Scutellaria baicalensis can be mediated in certain diseases (for example in skin diseases) by their ability to scavenge free radicals and by their protective effect on lipid peroxidation caused by sunlight irradiation.
A 5,6-Dihydro-isopyoverdin from Azomonas macrocytogenes
Authors: Michalke R. , Taraz K. , Budzikiewicz H. , Thonart Ph.
Published: August 2018

From the culture medium of Azomonas macrocytogenes a 5,6-dihydro-isopyoverdin could be isolated which includes the same peptide chain as the accompanying isopyoverdins (azoverdins). As analogous pairs had been encountered in the pyoverdin series where a dihydro derivatives are considered to be the immediate precursors of the pyoverdins, the same biogenetic sequence can thus be assumed for the iso-series.
Independently Acting Oxygen-Forming Complexes of Photosystem II in Cyanobacteria A Study in the Filamentous Cyanobacterium Oscillatoria chalybea
Authors: Spiegel S. , Burda K. , Bader K. P. , Schmid G. H.
Published: August 2018

It has been postulated that the oxygen-evolving centers of photosystem II do not operate independently in the cyanobacterium Synechococcus leopoliensis in contrast to those of the chlorophyte Chlorella vulgaris and the diatom Phaeodactylum tricornutum (Mauzerall and Dubinsky (1993), Biochim. Biophys. Acta 1183, 123-129). Dependence would mean the existence of charge transfer among adjacent units and would be manifested by different saturation curves for the individual flashes of a sequence (different cross-sections), stronger damped oscillations and oxygen formation under the first flash, independently of the length of dark adaptation. We show in the present publication that in the filamentous cyanobacterium Oscillatoria chalybea the O2-evolution pattern which shows an O2-signal under the first flash (despite dark adaptation) can be explained within the heterogeneous Kok-model, assuming a non-standard initial S-state distribution (Bader, Thibault and Schmid (1983), Z. Naturforsch. 38c. 778-792).
On the Formation of Whewellite in the Cactaceae Species Opuntia microdasys
Authors: Monje P. V. , Baran E. J.
Published: August 2018

The isolation of well formed crystals of the biomineral whewellite (monohydrated calcium oxalate) from Opuntia microdasys, a cactaceae species found in central Mexico, is described. The morphology of the crystals was investigated by means of electron microscopy. Infrared spectroscopic measurements allow an unambiguous characterization of the nature of the crystals. This is the first report of the presence of a biomineral in this species.
Notholaena Terpenoids: Two New Epimeric Diterpenes from the Frond Exudate of the Fern, Notholaena rigida
Authors: Arriaga-Giner Fco. Javier , Rumbero Angel , Wollenweber Eckhard
Published: August 2018

From the farinose frond exudate of the fern Notholaena rigida two new triterpenes have been identified. They were found to be the C-24 epimers of 12 β-acetoxy-24, 25-diO-isopropylidene-dammarane-3 β, 20(S),24,25-tetra-ol. A survey of all triterpenes found in Notholaena is presented.
Exudate Flavonoids in Asteraceae from Arizona, California and Mexico
Authors: Wollenweber Eckhard , Dörr Marion , Fritz Hannelore , Papendieck Sabine , Yatskievych G. , Roitman James N.
Published: August 2018

A series of Asteraceae, belonging to the tribes Astereae, Eupatorieae, Helenieae and Heli­antheae, have been analyzed for the presence of flavonoid aglycones accumulated on leaf and stem surfaces. Methyl ethers of apigenin, luteolin, kaempferol, and quercetin as well as methyl ethers of their relevant 6 -hydroxy derivatives were abundant, whereas 8 -O-substi-tuted derivatives and flavanones were encountered only occasionally; 6 ,8 -di-O-substituted flavonols were found in only one species.
Production of Calcium Oxalate Crystals by Two Species of Cyathus in Culture and Infested Plant Debris
Authors: Tewari Jalpa P. , Shinners Tracy C. , Briggs Keith G.
Published: August 2018

Hyphae of Cyathus striatus and C. olla in culture and on infested plant debris were heavily encrusted with crystals. Scanning electron microscopy revealed that raphide-and styloid­ shaped crystals were associated with the hyphae of C. olla in canola stubble and in culture. Bipyramidal crystals were also present in culture. Distinct raphide druses developed on C. striatus hyphae colonizing wood chips, but in culture most crystals were bipyramidal or other shapes. Energy-dispersive X-ray microanalyses, FT/IR spectroscopy, and 13C NMR spectros­ copy determined that these crystals were calcium oxalate. This is the first report of calcium oxalate crystal production by these fungi. This characteristic has implications towards decomposition of organic matter, biomineralization, nutrient cycling, and soil genesis.
Caffeine -DNA Interactions: Biochemical Investigations Comprising DNA-Repair Enzymes and Nucleic Acid Synthesis
Authors: Tempel Karlheinz , Zallinger Christina von
Published: August 2018

Chicken embryo cells were treated with caffeine (0.5-8.0 mᴍ) alone or combined with various chemical and physical DNA - and/or chromatin-interactive agents. Analytical procedures comprised scheduled (SDS) and unscheduled (UDS) DNA synthesis, RNA synthesis (RNS), the activities of O6-alkylguanine-DNA alkyltransferase (AT) and poly (ADP-ribose) polymerase (PARP) as well as nucleoid sedimentation. Additional investigations were done in rat thymic and splenic cells. The effect of caffeine on DNase-I activity served as an in vitro-model system.- When present in the PARP-, SDS-, UDS- and RNS-assays, caffeine inhibited the corresponding tracer (14C-NAD, dT-3H, 3H-U) incorporation in a dose-dependent manner. The AT activity was slightly stimulated. At concentrations of 0.06-0.3 mᴍ, caffeine inhibited DNase-I activity by excess substrate. No specific effects of caffeine could be shown by nucleoid sedimentation.- Besides the reduced permeability of the cells to nucleic acid precursors, the results obtained with the PARP- and DNase-I assays give evidence for the formation of a DNA-caffeine adduct as a prominent mechanism of cellular caffeine effects including DNA repair inhibition.
New Gadolinium Complexes as Magnetic Resonance Imaging - Contrast Agents
Authors: Wagner Manuela , Ruloff Robert , Hoyer Eberhard , Gründer Wilfried
Published: August 2018

We have investigated the physicochemical and paramagnetic properties of the new gado­linium complexes of N-(pyrid-2-yl-methyl)-ethylenediam ine-N,N',N'-triacetic acid (Gd-PED TA) and N -tris(2-aminoethyl)amine-N',N',N",N",N''',N'''-hexaacetic acid (Gd-TTAHA). The relaxivities as well as the thermodynamic and conditional stability constants of these complexes with respect to the physiological relevance were determined and discussed in comparison with the commercially available gadolinium(III) diethylenetriaminpentaacetic acid/ gadopentate dimeglumine (G d-DTPA, Magnevist®). In case of Gd-TTAHA a twofold higher relaxivity and a complex stability similar to Gd-DTPA were determined. It is shown, that lower concentrations of Gd-TTAHA are sufficient for the same signal enhancement in the T1-weighted MR image compared with Gd-DTPA and, thus, the use of the new contrast agent Gd-TTAHA should diminish risks for health. Therefore, Gd-TTAHA might be used potentially as a new contrast agent for clinical MRI application.
In Vitro Effects of Colchicine on Human Erythrocyte Membranes: An ESR Study
Authors: Korkmaz Özden , Korkmaz Mustafa , Aksöz Erol
Published: August 2018

Colchicine (CC) is an antimitotic and antitubular agent which is currently used in medicine as a drug to treat various diseases. In spite of its widespread use the interaction of this drug with membranes is not yet known clearly. To characterize alterations in membrane molecular dynamics produced by CC, human erythrocytes were spin-labeled with 5-doxylstearic acid (5-DSA) and 16-doxylstearic acid (16-DSA), and membrane fluidity was quantified by meas­uring the changes in the order parameter (S) which reflects the anisotropy due to restricted motional averaging, correlation time (τc) representing the spin label tumbling rate in the sample and phase transitions derived from ESR measurements. CC induced significant changes in both order parameter and correlation time at the surface of 5-DSA labeled membrane, but this was not the case at the core of 16-DSA labeled membrane. Order parameter, S and rotational correlation time, τc, showed a biphasic character in the temperature range of 5−50 °C. This fact was used to calculate phase transition temperatures and activation energies of untreated (control) and treated erythrocyte cells with CC.
Feral Honey Bees in the Sonoran Desert: Propolis Sources other than Poplars (Populus spp.)
Authors: Wollenweber Eckhard , Buchmann Stephen L.
Published: August 2018

In Central Europe and other temperate regions the lipophilic bee hive product propolis normally originates from the bud exudate of poplar trees that is collected by the bees. Based on bee observations, various other sources have been discussed in particular for tropical regions, but in only few cases the origin has been proved by analytical methods. We have analyzed propolis samples from managed honey-bees as well as from feral bee colonies in the Sonoran Desert. Propolis collected in hives out of flight reach of poplars contained flavonoid aglycones and other phenolics that point to specific plants as the source of propolis in this area, namely Ambrosia deltoidea and Encelia farinosa.
Leaf Flavonoids as Chemotaxonomic Markers for Two Erythroxylum Taxa
Authors: Johnson Emanuel L. , Schmidt Walter F. , Norman Helen A.
Published: August 2018

Leaf extracts of Erythroxylum coca var. coca Lam. (E. c. var. coca) yielded six O-eonjugates of Eriodictyol flavonoids, while the equivalent extracts from Erythroxylum novogranatense var. novogranatense (Morris) Hieron (E. n. var. novogranatense) contained five flavonoids, two of which were O-conjugates of Luteolin and three were O-conjugates of Kaempferol. All six of E. c. var. coca methanolic extracted peaks (resolved by HPLC) were found to have a 2, 3 single bond, which in E. n. var. novogranatense is replaced by a 2- hydroxy allene. The other primary difference in the predominant flavonoids between these taxa is the chemical composition of the sugar and/or acyl O-conjugation and site(s) at which this conjugation occurred. The results suggest that the most abundant O-conjugated flavonoids of E. c. var. coca and E. n. var. novogranatense may be used as chemotaxonomic markers for the two taxa. Therefore, the O-conjugated peaks of Eriodictyol , are distinct chemotaxonomic markers for E. c. var. coca and the O-conjugated peaks Luteolin and Kaempferol for E. n. var. novogranatense. These taxa are two of the four cultivated Erythroxylum taxa that contain commercial quantities of the cocaine alkaloid in their leaves, this entity also sets apart the taxa from other members of Erythroxylum. We suggest that the biochemistry of flavonoids of other Erythroxylum taxa may also be species selective
Reaction of Hypochlorous Acid with Bovine Nasal Cartilage Comparison to Pig Articular Cartilage
Authors: Schiller Jürgen , Arnhold Jürgen , Zachäus Annett , Klaus Arnold
Published: August 2018

The action of sodium hypochlorite (NaOCl) on bovine nasal cartilage was studied by proton nuclear magnetic resonance (1H-NMR) spectroscopy in order to model degradation processes of cartilage caused by neutrophil-derived hypochlorous acid.

Nasal cartilage was chosen as a mean of comparison because it differs from articular cartilage in its composition. It contains some more proteoglycans, i.e. polymeric carbohydrates and less collagen than articular cartilage. This is important for studying the influence of hypochlorous acid on cartilage components (collagen and polysaccharides). Cartilage samples were incubated at 37 °C with phosphate buffer in the presence or absence of NaOCl. Supernatants were collected and assayed by NMR-spectroscopy. In the presence of pure phosphate buffer, the supernatants of bovine nasal cartilage were less rich in low molecular mass metabolites (e.g. amino acids, lactate) than articular cartilage. However, intense signals for highly mobile N acetyl groups of cartilage polysaccharides were detectable in nasal cartilage.

NaOCl caused an increase in signals for acetate and formiate. Signals for N-acetyl groups rose only during the first 25 minutes of incubation with NaOCl. Then, their concentration decreased markedly. These changes were related to an enhanced release of Chondroitinsulfate from nasal cartilage
Effect of MgCl2 and Phosphatidylglycerol on CaCl2-Mediated Recovery of Oxygen Evolution in a Photosystem II Complex Depleted of the 17 and 24 kDa Extrinsic Proteins
Authors: Nénonéné E. K. , Méthot M. , Fragata M.
Published: August 2018

Phosphatidylglycerol (PG) is an anionic lipid of the thylakoid membrane of higher plant chloroplasts. PG was shown previously to stimulate the evolution of oxygen in intact pho­tosystem II (PSII) membranes [Fragata, M., Strzałka, K. and Nénonéné, E. K. (1991) J. Photochem. Photobiol. B: Biol 11, 329-342], In this work, a study was undertaken of the effect of MgCl2 and PG on the CaCl2-mediated recovery of oxygen evolution in a PSII complex depleted of the extrinsic proteins (EP) of molecular masses 17 kDa (EP17) and 24 kDa (EP24), hereunder designated d17.24PSII. This molecular system is structurally close to the PSII core complex of cyanobacteria and is therefore useful in the comparative analysis of PSII-PG relationships in cyanobacteria and the higher plants. This work reveals a new aspect of the thylakoid lipids role in the PSII function, namely the PG effect on intact PSII is observed as well in d17.24PSII. The results show that phosphatidylglycerol has the ability to compensate for the loss of EP17 and EP24 in the PSII complex. That is, PG restores the oxygen evolution in d17.24PSII incubated in the presence of MgCl2 and/or CaCl2 to the levels observed in native PSII. Moreover, the site of H2O degradation in d17.24PSII, including most probably the pool of calcium and chloride ions, would seem to be protected by phosphatidyl­glycerol. This suggests that one of the docking sites of PG in the PSII complex is near EP24, inasmuch as this extrinsic protein participates in the regulation of the affinity of the calcium and chloride ions to the water oxidation site. Furthermore, taking into account that in d17.24PSII the PSII core complex is directly exposed to PG, then the phospholipid effect reported here indicates that phosphatidylglycerol might be a functional effector and mem­brane anchor of the D1 protein in the PSII core complex as was shown recently in the cyanobacterium Oscillatoria chalybea [Kruse, O. and Schmid, G. H. (1995) Z. Naturforsch. 50c, 380-390],
Peroxidase-Polyphenol Oxidase Association in Dioscorea esculenta
Authors: Okpuzor J. , Omidiji O.
Published: August 2018

A crude enzyme extract from Dioscorea esculenta var. fasiculata tissue subjected to ion exchange chromatography on DEAE-Sephadex A-50 column. This proced ure resolved the extract into two main protein peaks one of which eluted through the column relatively unbound while the other protein peak which remained bound to the column was eluted with 1.0 ᴍ NaCl. Both protein peaks contained polyphenol oxidase (PPO) and peroxidase (POD) activities. The non-binding protein peak was resolved by gel filtration on Sephadex G-200 into distinct PPO and POD activities and by virtue of their apparent molecular weights of 95.5 Kd and 38.0 Kd for PPO and POD respectively were determined to be the typical enzymes. The PPO activity was completely inhibited invitro by 5 mᴍ polyvinyl pyrrolidone (PVP). The binding protein peak was not resolved by gel filtration. It contained PPO activity which was not inhibited by PVP and a POD activity which was completely inhibited by dithiothreitol (DTT) This ionic protein peak contained 60% of total POD in the tissue, has an apparent molecular weight of 56 Kd and is suggested to be a strongly anionic peroxidase which also exhibits polyphenol oxidase activity.
ʟ-Phenylalanine Effect on Rat Diaphragm Acetylcholinesterase and Na+,K+-ATPase
Authors: Tsakiris Stylianos , Kouniniotou-Krontiri Panagiota , Schulpis Kleopatra H.
Published: August 2018

The effect of different L-phenylalanine (Phe) concentrations (0.24-12.1 mᴍ) , on acetylcho­linesterase (AChE) and Na+,K+-ATPase activities of diaphragm homogenates from 21-day old rats and pure enzymes, was investigated at 37 °C. AChE and N a+,K+-ATPase activities were determined after preincubation with Phe. AChE activity in diaphragm homogenate or in pure eel E. electricus enzyme showed a decrease, which reached a maximum of 18% with Phe concentrations of 0.9-12.1 mᴍ. However lower Phe concentrations (0.24 mᴍ) increased the enzyme activity (by approximately 22%), only in the diaphragm homogenate. Dia­phragm-associated Na+,K+-ATPase activity showed a progressive and concentration-depen­ dent decrease, by about 30-35% in the presence of high Phe concentrations. Pure enzyme activity (from porcine cerebral cortex) was not affected by high Phe concentrations (>0.48 m M) , while it was increased by low concentrations. The above results suggest; a) A direct inactivating effect of high Phe concentrations on AChE and an indirect activating effect induced by low concentrations, b) A direct activating effect of low Phe concentrations and an indirect inactivating effect of high ones on Na+,K+-ATPase. c) The combination of high Phe concentrations effects on AChE and Na+,K+-ATPase could influence the levels of the diaphragm synaptic ACh.
Increased Levels of Lipid Oxidation Products in Rheumatically Destructed Bones o f Patients Suffering from Rheumatoid Arthritis
Authors: Jira Wolfgang , Spiteller Gerhard , Richter Andreas
Published: August 2018

The new indicator for lipid peroxidation (LPO) processes -9-hydroxy-10,12-octadecadie-noic acid (9-HODE) -was used to investigate, whether LPO processes are increased in destructed bone material of patients suffering from rheum atoid arthritis (RA) in comparison to surrounded non destructed bone material. The HODE content in destructed bones ex­ceeded that of non destructed ones of the same patient for a factor of about 3. In addition similar increases in leukotoxines and epoxy oleic acid in the destructed bone material were observed, indicating an increase of LPO processes in affected bone parts of pa­tients.
When Do Paederus riparius Rove Beetles (Coleoptera : Staphylinidae) Biosynthesize Their Unique Hemolymph Toxin Pederin?
Authors: Kellner Rupert L. L.
Published: August 2018

Pederin analyses of single Paederus riparius specimens reared from the egg and kept for prolonged periods of time show that only the females are able to biosynthesize the substance. Preimaginal stages efficiently store pederin transferred by the females into their eggs and the males’ pederin content decreases slowly over time. Only males with access to eggs con­ taining the substance moderately increase their pederin load. The females begin to accumu­ late the toxin a few weeks after imaginal eclosion and build up reserves for the egg laying period within 60 days. This is discussed with regard to the life cycle of P. riparius. During reproduction, when the females loose pederin due to maternal transfer, they must replenish their pederin reserves. This biosynthesis is not reflected in the amount found per individual.
Effect of Aging on the Activities of Acetylcholinesterase, Na+, K+-ATPase and Mg2+-ATPase in Rat Pituitary and Hypothalamus
Authors: Tsakiris Stylianos , Angelogianni Panagoula , Stavridis John C.
Published: August 2018

Acetylcholinesterase (AChE), Na+, K+-ATPase and Mg2+-ATPase activities were esti­mated in homogenised rat pituitary and hypothalamus of 4-and 22-month-old rats. AChE activity was not altered in the pituitary of aged com pared to adult rats, while it was found decreased by about 40% in the hypothalamus. Na+,K+-ATPase activity remained stable in the hypothalamus, while it was decreased by about 38% in the pituitary. Mg2+-ATPase activ­ity remained unchanged in the hypothalamus, but was increased by about 83% in the pitu­itary. This pituitary Na+, K+-ATPase inactivation may result in pathological mood and de­creased neural excitability and metabolic energy production in aged animals.The age-related alterations of AChE , Na+, K+-ATPase and Mg2+-ATPase activities may reflect changes in secretion and responses of some hormones of pituitary and hypothalamus.
Interaction of the Anticancer Drug Tamoxifen with the Human Erythrocyte Membrane and Molecular Models
Authors: Suwalsky M. , Hernández P. , Villena F. , Aguilar F. , Sotomayor C. P.
Published: August 2018

Tamoxifen, Anticancer Drug, Erythrocyte Membrane, Phospholipid Bilayer Tamoxifen is a non steroidal antiestrogen drug extensively used in the prevention and treatment of hormone-dependent breast cancer. To evaluate its perturbing effect upon cell membranes it was made to interact with human erythrocytes and molecular models. These consisted of bilayers of dimyristoylphosphatidylcholine (DMPC) and of dimyristoylphospha-tidylethanolamine (DMPE), representative of phospholipids classes located in the outer and inner leaflets of the erythrocyte membrane, respectively. Experiments by fluorescence spectroscopy showed that tamoxifen interacted with DMPC vesicles fluidizing both its polar head and acyl chain regions. These results were confirmed by X-ray diffraction which indi­ cated that tamoxifen perturbed the same regions of the lipid. However, it did not cause any significant structural perturbation to DMPE bilayers. The examination by electron micro­ scopy of human erythrocytes incubated with tamoxifen revealed that they changed their normal discoid shape to stomatocytes. According to the bilayer couple hypothesis, this result means that the drug is inserted in the inner leaflet of the erythrocyte membrane. Given the fact that tamoxifen did not interact with DMPE, it is concluded that it interacted with a protein located in the cytoplasmic moiety of the erythrocyte membrane.
Analysis of the Seed Lipids of Aleurites montana
Authors: Radunz A. , Heb P. , Schmid G. H.
Published: August 2018

The seed lipids of the Chinese tung-oil tree Aleurites montana are composed of 97.2% triglycerides, 2% phospholipids and of 0.8% glycolipids. In the triglycerides 67% of all fatty acids are α-eleostearic acid (configuration C18:3, ∆9 cis, ∆11 trans, ∆13 trans). This acid is bound in the triglycerides in the 1,3 position. Via mercury Il-acetate adducts and subsequent chromatography on silica gel a separation of this fatty acid from the seed fatty acids is possible. By this procedure an a-eleostearic acid-free tung-oil mixture is obtained, which consists by one half of C18:2, 25% of C18:1 and by 25% of the saturated fatty acids C16:0, C18:0 and C14:0.