Localization of methyl benzoate synthesis and emission in Stephanotis floribunda and Nicotiana suaveolens flowers.

The emission of fragrances can qualitatively and quantitatively differ in different parts of flowers. A detailed analysis was initiated to localize the floral tissues and cells which contribute to scent synthesis in STEPHANOTIS FLORIBUNDA (Asclepiadaceae) and NICOTIANA SUAVEOLENS (Solanaceae). The emission of scent compounds in these species is primarily found in the lobes of the corollas and little/no emission can be attributed to other floral organs or tissues. The rim and centre of the petal lobes of S. FLORIBUNDA contribute equally to scent production since the amount of SAMT (salicylic acid carboxyl methyltransferase) and specific SAMT activity compensate each other in the rim region and centre region. IN SITU immunolocalizations with antibodies against the methyl benzoate and methyl salicylate-synthesizing enzyme indicate that the adaxial epidermis with few subepidermal cell layers of S. FLORIBUNDA is the site of SAMT accumulation. In N. SUAVEOLENS flowers, the petal rim emits twice as much methyl benzoate due to higher total protein concentrations in the rim versus the petal centre; and, both the adaxial and abaxial epidermis house the BSMT (salicylic acid/benzoic acid carboxyl methyltransferase).

Effects of phytoestrogen extracts isolated from rye, green and yellow pea seeds on hormone production and proliferation of trophoblast tumor cells Jeg3.

BACKGROUND: Phytoestrogens are a diverse group of non-steroidal plant compounds. Because they have chemical structures similar to estrogens they are able to bind on estrogen receptors in humans. OBJECTIVES: In this study, we tested the effects of crude phytoestrogen extracts from rye (Secale cereale), green pea (Pisum sativum) and yellow pea seeds (Pisum sativum cv.) on cell proliferation and the production of progesterone in trophoblast tumor cells of the cell line Jeg3. METHODS: Isoflavone extracts from green and yellow pea seeds and lignan extracts from rye seeds were obtained, using different extraction methods. Isolated extracts were incubated in different concentrations with trophoblast tumor cells. Untreated cells were used as controls. At designated times, aliquots were removed and tested for estradiol and progesterone production. In addition, we tested the effects of the phytoestrogen extracts on cell proliferation. RESULTS: Cell proliferation is significantly inhibited by potential phytoestrogens isolated from rye, green and yellow pea seeds in trophoblast tumor cells of the cell line Jeg3. We found a correlation between the effects of proliferation and production of estradiol in isoflavone extracts from green and yellow pea seeds in Jeg3 cells. In addition, higher concentrations of isoflavones isolated from green pea seeds and lignans from rye showed also a inhibition of progesterone production whereas higher concentrations of rye lignans elevated estradiol production in Jeg3 cells. CONCLUSION: A useful indicator test system for potential phytoestrogens could be established. Based on the obtained results it is proposed that green and yellow pea seeds contain measurable concentrations of isoflavones and rye seeds contain lignans which can be isolated and used for special human diet programs.

Flax-seed extracts with phytoestrogenic effects on a hormone receptor-positive tumour cell line.

UNLABELLED: The higher soy intake in the Asian population compared to Europeans is believed to be an essential factor for the lower incidence of hormone-dependent tumours in Asia. It has already been shown that soya beans, with their ingredients genistein and daidzein from the isoflavonoid group, have protective effects on hormone-caused diseases. Lignans are another, less investigated, group of phytoestrogens. The aim of this study was to investigate the effects of flax-seed, which is typically found in Northern European diets, on the proliferation and hormone production of an estrogen receptor (ER)-positive trophoblast tumour cell line. MATERIALS AND METHODS: Trophoblast tumour cells of the cell line Jeg3 were incubated with 2 different concentrations of the isolated crude extract of flax-seed and 7 chemically partitioned extract fractions. Untreated cells were used as controls. After 48 h of stimulation, cell proliferation was measured using the BrdU method. The concentrations of hCG and progesterone produced by the trophoblast tumour cells were measured 48 h after stimulation. Extract fractions with antiproliferative effects in the BrdU- test were analysed by HPLC-MS. RESULTS: Our study showed an inhibitory influence of some of the isolated flax-seed fractions on the Jeg3 tumour cells. Proliferation of the Jeg3 cells was decreased by flax-seed fractions I, V, VI and VII in a dose-dependent manner. Inhibition of hCG production by flax-seed extracts III, V, VI and VII was also dose-dependent. Extract fractions V and VI decreased the production of progesterone by 58% to 86%. Some extract fractions showed a stimulating effect on hormone production and cell proliferation. HPLC-MS analysis showed the presence of matairesinol and biochanin A in flax-seed fraction VI. DISCUSSION: Flax-seed seems to have similar inhibitory effects to soya on hormone production and proliferation of hormone-sensitive tumour cells. Our results showed a dose-dependent inhibition by isolated flax-seed extracts on the Jeg3 cell line. Matairesinol and biochanin A seem to be useful candidates for extended tests on other tumour cell lines and normal tissues to evaluate the potential benefit of a lignan-containing therapy in hormone-dependent diseases.

Biochemical characterization of glucosylglycerol-phosphate synthase of Synechocystis sp. strain PCC 6803: comparison of crude, purified, and recombinant enzymes.

Glucosylglycerol-phosphate synthase (GGPS), the key enzyme of the glucosylglycerol biosynthesis in salt-stressed cells of Synechocystis, was biochemically analyzed in crude extracts, after partial purification by FPLC and after overexpression of the gene ggpS in Escherichia coli and purification to homogenity of the recombinant protein, respectively. These GGPS preparations behaved similarly with regard to temperature stability, pH optimum, Mg2+ dependence, inhibition by phosphates, and Km values, but differed in their dependence on NaCl concentration: crude enzyme needed activation by addition of NaCl, whereas both partially-purified and recombinant GGPS showed high activities independent of the NaCl concentration.

Biochemical and pharmacological investigations of selected cyanobacteria.

Cyanobacteria are a very old group of prokaryotic organisms that produce a variety of secondary metabolites with antibiotic, algicide, cytotoxic, immunosuppressive and enzyme inhibiting activities. In the last decades structures of pure compounds have been determined as phenols, peptides, alkaloids or terpenoids (Falch, 1996). Screening of lipophilic and hydrophilic extracts from cultured cyanobacteria or waterbloom material, isolated from German lakes and the Baltic sea for antiviral, antibiotic, immunomodulating and enzyme inhibiting activity in different in vitro systems revealed strains with interesting effects. These strains were cultivated in 45 litre photobioreactors to produce enough biomass for bioassay-guided isolation of the active substances. First results characterising active substances are reported.

Effect of gravity changes on the cyanobacterium Synechocystis sp. PCC 6803.

The impact of hypergravity and simulated weightlessness were studied to check whether cyanobacteria perceive changes of gravity as stress. Hypergravity generated by a low-speed centrifuge increased slightly the overall activity of dehydrogenases, but the increase was the same for 90 g and 180 g. The protein pattern did not show qualitative alterations during hypergravity treatment up to 180 g. Cells of Synechocystis PCC 6803 subjected to common stressors like salt, heat, and light clearly accumulated at least four general stress proteins (25, 31, 34, and 63 kDa, respectively). Three of these proteins could also be detected after hypergravity, but in such small amounts that their occurrence could only be taken as a weak indication of stress. Low-molecular-weight stress metabolites were not synthesized in response to hypergravity, indicating that this gravity change was unable to activate the osmotic signal transduction chain. Gravity-dependent alterations were observed only during simulated weightlessness (generated by a fast-rotating clinostat). The glutamate/glutamine ratio was significantly shifted toward a higher glutamine portion. Altogether, the results may indicate that moderate changes of gravity were hardly, if ever, sensed as stress by cyanobacteria.

Uptake and use of the osmoprotective compounds trehalose, glucosylglycerol, and sucrose by the cyanobacterium Synechocystis sp. PCC6803.

Accumulation of exogenously supplied osmoprotective compounds was analyzed in the cyanobacterium Synechocystis sp. PCC6803, which synthesizes glucosylglycerol as the principal osmoprotective compound. Glucosylglycerol and trehalose were accumulated to high levels and protected cells of a mutant unable to synthesize glucosylglycerol against the deleterious effects of salt stress. In the wild-type, uptake of trehalose repressed the synthesis of glucosylglycerol and caused metabolic conversion of originally accumulated glucosylglycerol. Trehalose cannot be synthesized by Synechocystis and was not or only insignificantly metabolized. Sucrose, which can be synthesized in low quantities by Synechocystis, was also taken up, as indicated by its disappearance from the medium. Sucrose was not accumulated to high levels, probably due to a sucrose-degrading activity found in cells adapted to both low- and high-salt conditions. Despite its low intracellular concentration, sucrose showed a weak osmoprotective effect in salt-shocked cells of a mutant unable to synthesize glucosylglycerol.

[Investigations of the immunomodulatory effect of cyanobacterial extracts]. / Untersuchungen zur immunmodulatorischen Wirkung von Extrakten aus Cyanobakterien.

Resulting from the knowledge that cyanobacteria (blue-green algae) are able to produce pharmacologically active substances the aqueous extracts from several cyanobacteria species and strains (Microcystis aeruginosa, Synechocystis aquatilis, Oscillatoria redekei, Anabaena flos-aque, Aphanizomenon flos-aquae, Oscillatoria rubescens, Oscillatoria tenuis) were tested for their immunomodulating activity. Extracts from Oscillatoria redekei 051, Oscillatoria tenuis 01 and Synechocystis aquatilis 428 caused an immunosuppression. They inhibited not only the incorporation of 3H-thymidine into mitogen stimulated lymphocytes but reduced also the number of plaque-forming cells of mice as shown by hemolysis-plaque-assay. Only extracts from Oscillatoria redekei 051 did not show any cytotoxic effects in lymphocyte cytotoxic test. This may be an evidence for a specific action on the proliferation of lymphocytes.