Band 39, Heft 3-4

The application of field desorption and fast atom bombardm ent mass spectrometry for molecular weight determination and structural elucidation of spirostanol and furostanol saponins isolated from Paris Polyphylla Sm. (Liliaceae) is reported. The capacity and limitations of these methods for sugar sequencing, differentiation of isomers and purity control of oligoglycosidic natural products are discussed

The isolation of Miotoxin-A*, a novel macrocyclic trichothecene from Baccharis coridifolia DC. (Compositae) is described. The structure has been determined to be 4-hydroxy-roridin E by means of NMR-spectroscopy and X-ray structure analysis

The bibenzyl batatasin III was formed de novo in aerial bulbils and tubes of Dioscoreaceae from dihydro-m-coumaric acid. In cell-free preparations, bibenzyl synthase activity and an O-methyltransferase converting 3,3′,5-trihydroxybibenzyl into batatasin III were detected. High rates of incorporation of dihydro-m-coumaric acid into a 9 ,10-dihydrophenanthrene (hircinol) showed that a pathway being known to occur in orchids is also effective in Dioscoreaceae. The biosynthesis of hircinol could be stimulated by infecting the aerial bulbils with various fungi. In parallel to the dihydro-w-coum aric acid pathway another biosynthetic reaction sequence leading to phenanthrenes was found to occur. The pathway was established in its principal steps: p-coumaric acid - trihydroxystilbene (resveratrol) - phenanthrene (batatasin I or iso-batatasin I)

Extracellular glycoproteins have been claimed to represent the specificity determinants within different races of Phytophthora megasperma f. sp. glycinea (form erly P. m. var. sojae) specifically infective in different soybean cultivars. Microsomal preparations of three different races of Pmg are capable of synthesizing both N-glycosidically linked oligosaccharides and short O-glycosidically linked oligomannoses in vitro from corresponding sugar nucleotides. In addition, lipidic glycosidic intermediates (dolichol type derivatives) serve as specific glycosyl donors. In general, the results demonstrate that the well-known ubiquitous biosynthetic pathway of asparagine-di-Nacetyl- chitobiose type glycoproteins is established in that fungus. The significance of the results regarding specific elicitors, suppressors, protectants, and extracellular glycoenzymes is discussed

Mature black cherry (Prunus serotina Ehrh.) seeds accum ulate high levels of the cyanogenic disaccharide (R)-amygdalin. Extracts from these seeds contain two β-glycosidases which have been identified and completely resolved by DEAE-cellulose ion-exchange chromatography. Amygdalin hydrolase hydrolyzed (R)-am ygdalin at an optimum pH of 5.5, releasing (R)-prunasin and D-glucose. This enzyme showed highest activity towards (R)-am ygdalin and failed to hydrolyze (R)-prunasin. linamarin, β-gentiobiose and cellobiose. A distinct β-glycosidase, prunasin hydrolase, displayed a pronounced preference for (R)-prunasin, hydrolyzing this cyanogenic monosaccharide at an optimum pH of 6.5 to mandelonitrile and D-glucose. Prunasin hydrolase was inactive towards (R)-am ygdalin, linamarin, and β-gentiobiose. Both enzymes showed significant activity towards the artificial substrates β-ONPGlu and β-PNPGlu but did not hydrolyze α-PNPGlu. In view of the pronounced specificity of these enzymes towards endogenous cyanogens, it is concluded that upon disruption of black cherry seeds (R)- amygdalin is catabolized to mandelonitrile in a stepwise manner (the sequential mechanism) by amygdalin hydrolase and prunasin hydrolase with (R)-prunasin serving as intermediate. Young fronds of Davallia trichomanoides are rich sources of (R)-vicianin (the β-vicianoside of (R)-mandelonitrile). A β-glycosidase, vicianin hydrolase, has been partially purified from frond extracts by ion-exchange chromatography. At the optimum pH of 6.0, this enzyme showed highest hydrolytic activity with (R)-vicianin, although both (R)-am ygdalin and (R)-prunasin could be hydrolyzed at approximately 15% of the rate observed with (R)-vicianin. It failed to hydrolyze β-gentiobiose, cellobiose, linamarin and α-PNPGlu. Closer exam ination revealed that (R)-vicianin and (R)-amygdalin were hydrolyzed at the aglycone-disaccharide bond (the simultaneous mechanism) yielding mandelonitrile and the respective disaccharides vicianose and β-gentiobiose

Pseudomonas fluorescens, Proteus vulgaris, and Serratia marcescens, members of the microflora of soil and waste water, attacked methionine in the presence of glucose. The sulfur of methionine was released as methane thiol, dimethyl sulfide and dim ethyl disulfide. The volatile sulfur com pounds were qualitatively and quantitatively investigated by gas chromatography. Dimethyl disulfide was formed of methane thiol by various bacteria to a different extent. Growing in the presence of oxygen, S. marcescens oxidized most of the m ethane thiol to dim ethyl disulfide. In the presence of glucose. P. fluorescens dissimilated m ethionine with production of m ethane thiol and dimethyl disulfide. The dissimilation was stimulated with decreasing glucose concentration

The content of aromatic units in polymaleic acid (PMA) prepared by standard procedures is determined by C -13 NMR and three different oxydation procedures. It is shown that all destructive oxydation procedures lead to an aromatic carbon content that is significantly higher than the aromaticity content expected from the m ethod of preparation and derived from the C-13 NMR spectra. It is concluded, that benzenecarboxylic acids are formed in the process of oxydation of PMA. The yield increases with the oxydative strength of the m ethod applied

A rapid method for initial quantitative estimation of the phosphate present in compound containing a carbon-phosphorus bond is described. Two phosphorus assays are employed. One assay is for total phosphorus, which can be determined by digesting with perchloric acid and the other assay is for total non phosphonate phosphorus which can be determined by digesting with sulfuric acid simultaneously. The difference between total phosphorus and the non phosphonate phosphorus determined represents the amount of phosphorus present in a carbon-phosphorus linkage in a crude phospholipids sample

1-substituted 2-O-hexadecylglycero-3-phosphocholines and some structural analogues were tested for their biological activity on two entirely different test systems: human thrombocytes and potato virus X in tobacco plants. Structural prerequisites for a high activity in both systems are the alkyl glyceryl ether structural element, a short-chain substituent in the C-1 position, and the phosphocholine grouping. Accordingly, 1-O-methyl derivative (2) and 1-O-acetyl derivative (5) have the strongest effect on the biological activity of both test systems. The intensity of the effect of the tested compounds does not correlate with membranolytic properties measured by the lytic action on red cells

Purified NAD-dependent glutamate dehydrogenase (EC 1.4.1.2) from pea seeds shows a pattern of seven catalytically active molecular forms. The individual forms display different heat stabilities. During incubation at 70 to 75 °C in the presence of protective agents (NADH, Ca 2+ , DTE) the more heat labile forms are converted into the most stable form. This result presents direct evidence that the multiple forms of pea glutamate dehydrogenase represent conform ational variants of a single protein species

Under aerobic conditions, O 2 uptake and production of O 2 - and H 2 O 2 by isolated NADPH - cytochrome c-(ferredoxin)-oxidoreductase from Euglena gracilis was strongly stimulated by adriamycin. Further stimulation was not observed with 0.1 mᴍ Fe 3+ -EDTA. Methionine fragmentation (measured as ethylene release), as a reliable indicator for the formation of OH - radical-like oxidants under aerobic conditions (100 μmol O 2 in a 10 ml reaction vessel) was strongly stimulated by 0.1 mᴍ Fe 3+ -EDTA or, in the absence of iron, by partial anaerobiosis (1 μmol O 2 per vessel). The highest rate of methionine fragmentation was observed under anaerobic conditions in the presence of both reduced adriamycin and added H 2 O 2 . Aerobic methionine fragmentation in the presence of adriamycin and Fe 3+ -EDTA was inhibited by superoxide dismutase and catalase by more than 90%, while methionine fragmentation under semianaerobiosis in the absence of Fe 3+ -EDTA was inhibited by superoxide dismutase to only about 50%, while catalase again inhibited by more than 90%. These results indicate that the adriamycin-catalyzed production of a strong oxidant appears to be governed by different mechanisms depending on oxygen availability; namely the production of a Fenton-type oxidant driven by adriamycin-catalyzed superoxide formation and also, the formation of the “crypto-OH - radical” by direct electron donation from the adriamycin semiquinone radical to H 2 O 2 under oxygen limiting conditions

In analogy to chloroplast fatty acid synthesis from acetate the key enzymes of acetate fixation, acetyl-CoA synthetase and acetyl-CoA carboxylase, in rapidly Triton X-100 lysed spinach chloroplasts show an activation by light and deactivation in the dark. The stim ulation of acetyl-CoA carboxylase by dithiothreitol in darkened chloroplasts points to an involvement of reducing equivalents in the light activation of this enzyme. But more than by alterations of the activation state per se, these enzymes appear to be effected by changes in their catalytic activity due to differences in the proton-, Mg 2+ - and adenine nucleotide levels of the chloroplast stroma. Thus the pH dependence of both enzymes, as immediately extracted from Triton X-100 lysed chloroplasts, resembles that recently found for lipid incorporation of acetate into intact spinach chloroplasts in the light with an identical pH optim um of about pH 8.5 for the acetyl-CoA carboxylase. Moreover, in the same extracts both enzyme activities show the already postulated requirement for MgATP and free Mg and are com petitively inhibited by free ATP and ADP with respect to MgATP. But on account of the fact, that the extractable acetyl-CoA synthetase as opposed to the carboxylase activities exceed by far the lipid incorporation rates of acetate by illuminated chloroplasts before disruption, acetyl-CoA synthetase will be excluded as rate limiting step in fatty acid synthesis from acetate. From key enzymes of acetate fixation only the carboxylase appears to be involved therefore in the light regulation of acetate incorporation into long-chain fatty acids

Ribonucleoside diphosphate reductases isolated from Escherichia coli, baker’s yeast, Ehrlich ascites tumor cells, and a unicellular green alga (Scenedesmus obliquus) are inhibited strongly and uniformly by the polymeric triphenylmethane dye, aurintricarboxylic acid. The molecule appears to interact simultaneously with the enzyme’s various nucleotide and catalytic (iron-organic radical) sites. Oligo- and polyribonucleotides are also inhibitory. These reactions serve as models of the probably physiologic regulation of ribonucleotide reduction exerted by natural inhibitors. Partial characterization of an inhibitor fraction found in wheat seed embryo is described

The effect of pressure on the calcium dependent hydrolysis of para-nitrophenyl phosphate by the calcium transport enzyme of the sarcoplasmic reticulum was studied under different conditions: temperature, solutes, substrate and ion concentrations. The calcium transport enzyme exhibits a large positive activation volume which does neither depend on the enzyme’s inhibition by high salt concentrations nor its activation by ethylene glycol. The activation volume further proves to be pressure-independent but exhibits a pronounced negative temperature coefficient. The volume changes connected with the entrance of para-nitrophenyl phosphate, calcium or magnesium ions into the substrate ion complex are quite small, indicating that the transfer of water connected with the binding of these ligands is compensated by volume changes of the protein, accompanying the transition of the enzyme from its activated into its ground state

The calcium-dependent acylphosphate formed by the calcium transport ATPase of cardiac sarcoplasmic reticulum and the calcium-, calm odulin-dependent phosphoester(s) of sarcoplasmic reticulum fractions formed by a calcium-, calmodulin-dependent membrane-bound protein kinase can be distinguished by removal of calcium and/or magnesium by EDTA or hydroxylamine treatment of the acid denaturated membranes. Both procedures decompose the acylphosphate with little effect on the phosphoester(s). Calmodulin-dependent phosphorylation (2.44 nmol/mg SR protein) reduces the apparent K(Ca) of the acylphosphate steady state level of the calcium transport ATPase from 0.56 to 0.34 μM free calcium, without affecting the maximum phosphoenzyme level (0.93 versus 0.89 nmol/mg protein), and has little, if any, effect on the Hill-coefficient (1.32 versus 1.54)

Two classes of tributyltin (TBT) resistant, spontaneous mutants of Escherichia coli K-12 were isolated, using a cytochrome containing (W 1485) and a cytochrome deficient (SASX76) strain. In contrast to the cytochrome sufficient strain, the cytochrome deficient strain was found to be fifty times more sensitive to TBT. The class I mutants, isolated from strain W 1485, also showed crossresistance to triphenyltin (TPT). As compared to its wild type parent, the TBT-resistant mutants exhibited mucoid colony type, aberrant cell morphology and reduced uptake of TPT. Based on these results, it was suggested that the resistance of class I mutants to TBT may be associated with above mentioned alterations. The class II TBT-resistant mutants were isolated from the cytochrome deficient strain, SASX76. In comparison to class I mutants, these class II mutants were found to have TBT-resistant membrane bound adenosine triphosphatase (ATPase) which may account for their resistance to TBT

Photodestruction of Propionibacterium acnes was investigated by broad-band near-ultraviolet light. The inactivation of the bacteria was found to be oxygen dependent, and without O 2 , practically no photoinactivation occurred. D 2 O caused an increased inactivation (D 10 = 5 kJ/m 2 - in D 2 O as compared to D 10 = 11 kJ/m 2 in normal water). Decreased temperature during illumination increased the ability to form colonies. The results are compared with corresponding results for other types of cells and the destruction mechanism is discussed

Members of the genus Cistus excrete a leaf resin that consists mainly of terpenoids. This resin also contains methylated flavonoids as aglycones. Rare methyl derivatives of myricetin have been isolated from C. monspeliensis, along with uncommon methyl derivatives of quercetin. Further flavonoids encountered in the leaf resin of this and six further species are methyl derivatives of kaempferol and quercetin, some of apigenin and in one species also of luteolin. The results indicate that there might exist species-specific flavonoid patterns

The title compound, a new dimer of coniferyl alcohol is the second benzofuran derivative isolated from Herpetospermum caudigerum seeds. Its structure has been elucidated by spectroscopic means as Δ 7,7′(E) 4,9,9′-trihydroxy- 5,5′-dimethoxy-7.0.4′,8.3′-lignoid

The flavone di-C -glycoside earlier isolated from Radula complanata and tentatively identified as tricetin 6-C-β-dglucopyranosyl- 8-C-α-ʟ-arabinopyranoside is now positively identified by 13 C- and 1 H-NMR spectroscopy. Although this com pound is thought to have been isolated before, this is the first substantial support for its structure, previously assigned on the basis of MS evidence

Sphagnum acid is a cinnamic acid which up to now has only been traced in the cell walls of Sphagna. This plants contain this substance up to the quantity of 100 (μg per 100 mg dry weight. p-Hydroxy-β-[carboxymethyl]-cinnamic acid can be produced synthetically by condensation of phenol and acetonedicarboxylic acid

The volatile constituents of the black stink bug, Aethus indicus Westwood (Hemiptera: Pentatomidae) from Nigeria has been examined by combined gas chromatography- mass spectrometry. γ-Butyrolactone along with with several straight carbon-chain aliphatic materials have been identified in the scent gland complex

A reaction mechanism is presented for strand break formation in poly U induced by OH radicals in N 2 O/O 2 - saturated aqueous solution based on experimental results obtained with different methods

Partially purified chloroplast ATP synthase was reconstituted into asolectin liposomes. A valinomycine induced potassium diffusion potential from outside to inside the vesicles promoted a measurable ATP synthesis. If valinomycine was replaced by nigericine, practically no ATP was formed

Vegetative cells and spores of a yeast-like micro organism found in various tissues in both sexes of the ichneumonid wasp Pimpla turionellae are passed to the offspring by infection of the oocytes. Because of their intranuclearspindles with spindle pole bodies associated with the nuclear envelope as pole structures, the microorganisms are thought to be yeasts or closely related to yeasts. The high vitality and fertility of the wasps seem to exclude a pathogenic infection. Both the passage of vesicles from the microorganisms to the host cytoplasm and their transmission to the next generation by the oocytes point to anendosymbiotic relationship