Volume 58, Issue 11-12

Fire blight, a devastating bacterial disease in pome fruits, causes severe economic losses worldwide. Hitherto, an effective control could only be achieved by using antibiotics, but this implies potential risks for human health, livestock and environment. A new approach allows transient inhibition of a step in the flavonoid pathway, thereby inducing the formation of a novel antimicrobial 3-deoxyflavonoid controlling fire blight in apple and pear leaves. This compound is closely related to natural phytoalexins in sorghum. The approach does not only provide a safe method to control fire blight: Resistance against different pathogens is also induced in other crop plants.

The Mediterranean Ononis species, O. fruticosa, O. natrix subsp. ramosissima and O. tridentata, have been analyzed for their exudate flavonoids. More than 20 flavonoid aglycones were identified, some of which are rather rare natural compounds. One of them, namely hypolaetin- 8,3′,4′-trimethyl ether, had been found only once before. The results are presented in a table along with literature data, and the chemotaxonomic impact of the flavonoid patterns is discussed.

The alkaloid composition of the aerial parts of two taxa of Teline maderensis was studied by capillary GLC and GLC-MS. N-Methylcytisine was the major alkaloid found in both plants. Contents of cytisine and lupanine were higher in T. maderensis var. paivae while anagyrine content was more pronounced in T. maderensis var. maderensis. The alkaloids dehydrocytisine, N-acetylcytisine and epibaptifoline appeared only in T. maderensis var. maderensis and N-formylcytisine was identified as a minor constituent in T. maderensis var. paivae, and detected only in trace amounts in the other variety of the plant.

The volatiles of fresh flowers from nine natural populations of four Lamium species and Lamiastrum galeobdolon were analyzed by GC/MS. 49 compounds, 43 of them new for Lamium and Lamiastrum, were identified. The studied samples showed similarity of the volatile profiles and dependence of the oil-composition on the collection site. Significant amounts of squalene were found in all samples. The presence of homological series of straight chain alkanes from C 12 to C 31 was shown. Phenethyl alcohol was found only in L. maculatum f. alba.

The chemical composition of the lipophylic fraction from the halophytic plant Euphorbia peplis L. was investigated. Compared to other terrestrial higher plants an increase of triacylglycerols and especially of glycolipids was observed. The main phospholipid was phosphatidyl choline, followed by almost equal concentrations of phosphatidyl ethanolamine and phosphatidyl glycerol. A relatively high concentration of phosphatidic acids (6.5% of the total phospholipids) was found. The main sterol appeared to be sitosterol and significant amounts of tetracyclic triterpene alcohols were found. The composition of the volatile compounds is relatively simple and only one chlorinated compound, identified as 2,2-diethoxy-1-chloroethane, was found. There was a strong toxicity of the total lipophylic extract towards Artemia salina.

Two eudesmanolides, eight lactucin-like guaianolides and five phenolic compounds were isolated for the first time from roots of Cichorium pumilum, along with two previously reported eudesmane-type sesquiterpene lactones. Rearrangements of some lactucin-like guaianolides during isolation procedures were also discussed.

From the aerial parts of Santolina pinnata subsp. neapolitana, one new and four known germacrane derivatives were isolated. The new compound was characterized as 1α,10β- epoxy-7αH-germacr-4(15)-ene-2β,5α,6β-triol by spectral methods.

Volatile constituents of various solvent extracts (n-hexane, CH 2 Cl 2 , H 2 O) of 15 different organs (leaves, flowers, fruits) of five Rhododendron species (Ericaceae) growing in Turkey were trapped with headspace solid-phase microextraction (HS-SPME) technique and analyzed by GC-MS. A total of 200 compounds were detected and identified from organic extracts, while the water extracts contained only traces of few volatiles. The CH 2 Cl 2 extract of the R. luteum flowers was found to exhibit the most diverse composition: 34 compounds were identified, with benzyl alcohol (16.6%), limonene (14.6%) and p-cymene (8.4%) being the major compounds. The CH 2 Cl 2 -solubles of R. x sochadzeae leaves contained only phenyl ethyl alcohol. This study indicated appreciable intra-specific variations in volatile compositions within the genus. Different anatomical parts also showed altered volatile profiles. This is the first application of HS-SPME-GC-MS on the volatiles of Rhododendron species.

Using GC-MS the volatile composition of Jasonia glutinosa D. C., was studied by comparing two different methods for the isolation of a volatile fraction: distillation from the fresh plant in order to obtain the essential oil, and direct thermal desorption (DTD). Compared with essential oil extraction the main advantages of the DTD technique are the smaller sample amount required, and the increased range of volatile compounds which can be subsequently analysed by GC-MS.

Silyl and acetyl derivatives of sporopollenin from the pollen of Typha angustifolia L. were prepared. The derivatized products were readily soluble in piperidine-d 11 and could be investigated employing one- and two-dimensional proton and carbon NMR (nuclear magnetic resonance) spectroscopy ( 1 H, 1 H-COSY and 13 C, 1 H-HETCOR techniques). For the first time, a two dimensional 13 C, 1 H-HETCOR NMR spectrum of a sporopollenin could be obtained. The results underline the importance of derivatization techniques for obtaining two dimensional 13 C-NMR spectra of sporopollenins. Moreover, piperidine turns out to be a more suitable solvent for sporopollenins than 2-aminoethanol, as it allows for higher solubilities, being important for 2D-NMR investigations. From the HETCOR and COSY spectra of the silylated and the acetylated Typha samples the occurrence of aliphatic polyhydroxy compounds as well as phenolic OH groups became evident.

Calcium oxalate crystallites occur very often in the plants tissues and their role is still poorly known. We report here the experimental protocol leading to the isolation of two forms of calcium oxalate crystallites differing in their hydration level in the parenchymal tissues of Opuntia ficus indica (Miller). Whereas the whewellite crystallites are habitual in all Opuntia species, the weddellite form has never been isolated from these species before, which is probably due to their small size (about 1 μm). We have identified these forms using X-ray diffraction and scanning electron microscopy.

The aerial parts of Artemisia chamaemelifolia Vill. afforded, in addition to five known sesquiterpene acids, a new 5-epi-cantabrenolic acid (6).

Two new phenylethanoid glycosides integrifoliosides A (2) and B (3), along with a known phenylethanoid glycoside alyssonoside (1) and a flavone glucoside chrysoeriol-7-O-β-ᴅ-glucopyranoside (4) were isolated from the aerial parts of Phlomis integrifolia. The structures of the new compounds were identified as 3,4-dihydroxy-β-phenylethoxy-O-β-ᴅ-apiofuranosyl- (1 →4)-α-ʟ-rhamnopyranosyl-(1 →3)-4-O-feruloyl-β-ᴅ-glucopyranoside (2) and 3-hydroxy-4-methoxy-β-phenylethoxy-O-β-ᴅ-apiofuranosyl-(154)-α-ʟ-rhamnopyranosyl-(1→3)-4-O-feruloyl-β-ᴅ-glucopyranoside (3), on the basis of spectroscopic (UV, IR, 1D- and 2D-NMR, and HR-FABMS) methods.

Phlomis linearis Boiss. & Bal. of the Lamiaceae family growing in central, east and southeast Anatolia is an endemic species for Turkey. The essential oil obtained from the aerial parts by hydro distillation was subsequently analyzed by GC/MS. The main components of the oil were found as β-caryophyllene (24.2%), germacrene D (22.3%) and caryophyllene oxide (9.2%), among 49 identified compounds, representing 94.5% of the total essential oil. The overall biological activity of the essential oil (100 μg/pellet) was tested on the chorioallantoic membrane (CAM) of the fertilized hen’s egg in order to examine the anti-angiogenic and anti-inflammatory activity. None of the tests showed pronounced activity, toxicity or irritation at the tested concentration.

The anti-inflammatory activity of four total extracts, their fractions and two main constituents (α-bisabolol β-ᴅ-fucopyranoside and luteolin 7-O-glucoside) of Carthamus lanatus L. aerial parts, were assessed in vitro by determining the inhibitory effects on induced human neutrophils. The dichloromethane extract and its water-alcoholic part exhibited the most significant inhibitory effects.

The clastogenic effect of total dichloromethane, methanol and water extracts, four bioactive fractions and three individual constituents from Carthamus lanatus aerial parts were evaluated in mice by bone marrow chromosome aberration assay with mitomycin C as positive control. Significant differences in the percentage of aberrant mitosis of the extracts were observed. The dichloromethane extract exhibited a considerable clastogenic effect and the water extract a negligible one. Different types of chromosome aberrations and time-dependant effects for the active fractions and individual compounds were found.

Characterization and selection of olive clones for the production of olive oil is essential in Turkey because of its profitable exploitation. AP-PCR (Arbitrarily-Primed PCR) is a technique that can distinguish the genetic relationship among plant species and other organisms. In this study, AP-PCR approach was used in order to determine the genetic relationship of different six olive clones. The purity of DNA is one of the most important factors affecting the product of the AP-PCR method. In this respect, modified genomic DNA isolation procedure from Oleae europaea clones was developed so that this procedure can be used to obtain plant genomic DNA from diverse aromatic plants, which produce essential oils and secondary metabolites. By following the optimized AP-PCR amplification protocol, unique DNA fingerprint profiles for each olive clone were produced. AP-PCR-generated unique DNA fingerprint profiles can be used in the identification, distribution and diversity of various olive cultivars.

Reports on stress response of tobacco expressing a bacterial glutathione reductase (GR) do not agree. To clarify this situation we investigated several parameters using the tobacco BelW3 line and its transformant BelW3gor expressing an E. coli GR. This alteration in the activity of GR led to an ambiguous modification of the antioxidative system. In contrast to the wild type, the transgenic tobacco suffered lipid peroxidation under moderate light intensities, while it was found to be more resistant towards oxidative stress induced by paraquat or hydrogen peroxide. Transcript levels for violaxanthin deepoxidase and cytosolic Cu-Zn-superoxide dismutase were strongly reduced in BelW3gor plants as compared to BelW3.

In this study, the antimicrobial activity of the acetone, diethyl ether and ethanol extracts of the lichen Cetraria aculeata has been investigated. The extracts were tested against twelve bacteria and eight fungi and found active against Escherichia coli, Staphylococcus aureus, Aeromonas hydrophila, Proteus vulgaris, Streptococcus faecalis, Bacillus cereus, Bacillus subtilis, Pseudomonas aeruginosa, Listeria monocytogenes. No antimicrobial activity against the fungi was detected. It was determined that only one substance in the extracts has antimicrobial activity and it was characterized as protolichesterinic acid. The MICs of the extracts and protolichesterinic acid were also determined.

The effect of six various pesticides on the growth of yeasts isolated from agricultural soil was investigated. Two herbicides (with the effective substances lactofen and metazachlor), two fungicides (with the effective substances fluquinconazole and prochloraz), and two insecticides (with the effective substances cypermethrin + chlorpyrifos and triazamate) were tested. It is evident that there are considerable differences in inhibition effects of studied pesticides. The fungicide with the effective substance prochloraz inhibited the growth of majority of yeast strains. The insecticide triazamate at concentration 0.6 mm restricted or inhibited growth of all tested strains. The strains of the genus Cryptococcus were the most sensitive to pesticides, while the strains of the species Cystofilobasidium capitatum, Debaryomyces occidentalis var. occidentalis, and Trichosporon cutaneum were the most resistant.

The occurrence and metabolism of nicotine and related N-containing compounds in body fluids of the gipsy moth were addressed. Thin layer chromatographic studies clearly showed the simultaneous presence of GABA and 2-pyrrolidone but not of GABamide in the larval haemolymph and osmeterial secretion of Lymantria dispar as well as in the corresponding body fluids of the saturniids, Saturnia pavonia and Attacus atlas. Furthermore, feeding and injection experiments using alkylated precursors and combined gas chromatography/mass spectrometry gave evidence of the transformation of 2-pyrrolidone to nicotine and of nicotinic acid to nicotinamide in caterpillars of L. dispar. Based on these results, on the earlier described variation of the secondary-compound patterns of L. dispar during its development, and on literature data, metabolic pathways for the hitherto detected pyridyl and pyrrolidonyl alkaloids in Lymantriidae (and possibly Saturniidae) are proposed.

Many chlorinated phenols and their derivatives are used extensively as insecticides, fungicides and herbicides by industrial and agricultural users throughout the world. Among these substances, pentachlorophenol (PCP) is a broad-spectrum biocide, which is still used as a wood preservative. In this paper, the digestive gland cells were used to assess the effect of PCP in the range of concentrations 3.75-75 μᴍ (0.01-0.2 ppm) on oxidative DNA damage, fluidity changes and peroxidation activity in the plasma membrane. The toxic property of PCP on DNA strand breakage was studied using the comet assay. The results showed that pentachlorophenol in the range of 37.5-75 μᴍ contributed to these lesions. To demonstrate the changes in the fluidity of plasma membrane we used the spectrofluorimetric method using two fluorescence probes: 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene (TMAD DPH) and 12-(9-anthroyloxy) stearic acid (12-AS). It was shown that PC did not influence the surface of plasma membrane but contributed to the increase in the fluidity of the internal region of the lipid bilayer in the range of concentrations 18.75-75 μᴍ (0.05-0.2 ppm).We also examined the effect of PCP on the lipid peroxidation. To imply its peroxidation properties the spectrophotometry method was used to measure the level of malondialdehyde (MDA), one of the endpoints of the peroxidation of polyunsaturated fatty acids. The obtained results showed that PCP in the used doses did not initiate the formation of lipid peroxides. Thus, our investigation indicates that PCP can behave as a prooxidant agent but its action depends on the used doses and parameters chosen for the research.

Polypentapeptides (GVGVP) n which are designed in analogy to the connective tissue protein elastin are reported to transform various kinds of energy into mechanical work by the so-called ⊿T t -mechanism in cross-linked macroscopic polypentapeptide (PPP) films. In the literature, the responsible element of conformation in such polypeptides is described as a β- spiral and the ⊿T t effect is explained as a sudden change of macroconformation of single polypeptide molecules from an extended but not regular state below a transition temperature T t to the β-spiral above T t . We examined the secondary structure of the linear PPPC(GVGVP)6 in solution with DSC, CD, UV absorption, FTIR and NMR spectroscopy. The results suggest that the β-spiral is not present in the conformational structure of the PPP molecules. The antiparallel β-sheet is proposed to be the basic regular part of conformation because it agrees with all spectroscopic data. As a consequence, the elasticity of natural elastin must be considered from a new perspective.

Many bacteria utilize sophisticated regulatory systems to ensure that some functions are only expressed when a particular population density has been reached. The term ‘quorumsensing’ has been coined to describe this form of density-dependent gene regulation which relies on the production and perception of small signal molecules by bacterial cells. As in many pathogenic bacteria the production of virulence factors is quorum-sensing regulated, it has been suggested that this form of gene regulation allows the bacteria to remain invisible to the defence systems of the host until the population is sufficiently large to successfully establish the infection. Here we present first evidence that polyphenolic compounds can interfere with bacterial quorum-sensing. Since polyphenols are widely distributed in the plant kingdom, they may be important for promoting plant fitness.

Cytarabine, an analog of deoxycytidine, is an important agent in the treatment of ovarian carcinoma, acute myeloid and lymphoblastic leukemia. Its mechanism of action has been attributed to an interference with DNA replication. The plasma membrane has received increasing attention as a possible target of antitumor drugs, where the drugs may act as growth factor antagonists and receptor blockers, interfere with mitogenic signal transduction or exert direct cytotoxic effects. Furthermore, it has been reported that drugs that exert their antiproliferative effect by interacting with DNA generally cause structural and functional membrane alterations which may be essential for growth inhibition by these agents. This paper describes the studies undertaken to determine the structural effects induced by cytarabine to cell membranes. The results showed that cytarabine, at a concentration about one thousand times higher than that found in plasma when it is therapeutically administered, did not induce significant structural perturbation in any of these systems. Therefore, it can be unambiguously concluded that this widely used anticancer drug does not interact at all with erythrocyte membranes.

A water-soluble polysaccharide was isolated from the culture filtrate of a fungal strain, Sphaeropsis sp. TNPT116-Cz, as a novel insect chitinase inhibitor. It was purified to chromatographic homogeneity by ethanol precipitation, anion-exchange and gel filtration chromatography. Its molecular weight was estimated to be 16 kDa by gel filtration HPLC. Monosaccharide analysis showed that it contained glucose, galactose, N-acetylglucosamine and a deoxysugar. This polysaccharide showed potent and specific inhibitory activity against Spodoptera litura chitinase with an IC 50 value of 28 nᴍ.

The effect of the gene dosage on the expression of rRNAs was studied in Hypericum perforatum. The methylation levels of rDNA were analysed using the isoschizomers MspI and HpaII and eleven additional methylation-sensitive enzymes. No differences in rDNA methylation were observed between diploids and tetraploids at an early ontogenetic stage.