Volume 49, Issue 3-4

From the poisonous mushroom Clitocybe acromelalga, a new glutam ate-containing dipeptide was isolated. Its structure was deduced to be N-(γ-aminobutyryl)-ʟ-glutamic acid (10) based on spectral data and was confirmed by synthesis

D-Enzyme (4-a-glucanotransferase, EC 2.4.1.25) from cultured symbiotic Nostoc and Chlorella has been partially purified and characterized. The enzyme catalyzes the disproportionation of maltooligosaccharides and is able to form maltooligosaccharides from soluble starch and D-glucose. The properties of D-enzyme from Nostoc and Chlorella are similar with respect to substrate specificity, K M values and pH dependence, but differ with respect to temperature optimum and molecular weight (40 °C/50 kDa and 50 °C/230 kDa for the enzyme from Nostoc and Chlorella, respectively). D-enzyme activity has been demonstrated also in freeliving Anabaena, Chlorella and Chlamydomonas. Its physiological role in symbiotic Nostoc is briefly discussed

The main objective of this study was the com parison of changes in levels of α-tocopherol and ascorbate in needles of spruce trees with various degrees of damage at three low mountain sites. The ascorbate content in needles of spruce trees with various degrees of dam age differs in the course of seasons as well as in the absolute level. The antioxidant status was affected mainly during summer. The content of ascorbate in needles of dam aged trees was significantly increased compared to that of undamaged trees. Despite seasonal and daily fluctuations, the level of ascorbate seems to be a good indicator for the degree of dam age in the case of symptoms described as montane yellowing. Together with an increasing content of α-tocopherol per chlorophyll, a rise of ascorbate content indicates enhanced oxidative stress in the needles of damaged trees, particularly in summer. Asc/αToc ratios were increased in needles of damaged trees. At the studied sites enhanced oxidative stress could be caused by the com bined action of Mg 2+ -deficiency, high ozone concentrations and high-light intensity, all inducing an increased production of radicals in combination with a reduced photosynthetic capacity

The levels of free, conjugated and bound polyamines (PA) were analyzed during the cell cycle of the synchronized unicellular green alga Scenedesmus obliquus. The polyamines putrescine (PUT) and spermidine (SPD) in their free and conjugated forms accumulated per cell to a maximum in the cell cycle at about the 16 th hour after onset of illumination. The polyamines bound to macromolecules and membrane systems showed an additional peak around the 8-10 th hour of the cell cycle. The possible role of the different forms of polyamines in DNA replication, mitosis, cell division and development of the photosynthetic apparatus is discussed

For establishing metribuzin-resistant, photoautotrophic Chenopodium rubrum cell cul­tures plated cells, callus cultures or suspension cultures were subjected to selection proce­ dures. The most effective procedure was the stepwise increase in the concentration of the herbicide from 0.01 μᴍ to 10 μᴍ in suspension cultures, which resulted in the isolation of eight different metribuzin-resistant photoautotrophic cell lines. Conjugation metabolism or a decrease in the uptake and translocation of the selective agent were not responsible for resist­ ance, which was stable in the absence of the inhibitor over numerous growth cycles. Meas­ urements of the photosynthetic electron transport, analyses of fluorescence induction kinetics and determination of the binding properties of 14 C-labelled metribuzin to isolated thylakoids indicated that resistance of the cell lines is based on an alteration in the photosystem II her­ bicide-binding protein (D 1 protein). RFLP analysis of the psbA gene of the eight resistant cell lines demonstrated that none of them possess an amino acid exchange in position 264 of the D1 protein leading to altered herbicide-binding properties.

We have analyzed the tissue-specific expression of chitinase, β-1,3-glucanase and, for com parison, phenylalanine ammonia-lyase genes in healthy, unstressed potato (Solanum tuberosum) plants by using RNA -RNA hybridization and immunostaining techniques to localize the respective mRNAs and proteins in situ. Preparations of leaf, flower, shoot tip, node and axillary bud revealed that chitinase exhibited a distinctive and characteristic expression pattern in being confined to the epidermal cell layer, while β-1,3-glucanase and phenylalanine ammonia-lyase were present to varying extents in most tissues of these organs. These distinctive patterns of expression suggest fundamentally different roles for the two glucanohydrolases in the metabolism of unstressed plants

The addition of 7-chloro-4-nitrobenzofurazan (NBD) to isolated CF 1 at pH 7.5 leads to one tyrosine-bound NBD molecule per CF 1 in one of the three β-subunits, concomittantly with the inhibition of the ATPase activity. Addition of ADP prior to NBD -incubation protected the ATPase activity and reduced binding of NBD to β-subunits. The addition of MgATP prior to modification did not result in protection against modification of the β-subunit as well as preservation of activity. Cleavage of the NBD -labelled subunits with cyanogen brom ide, follow ed by analysis of the labelled peptides, led to detection of a 14 C-labelled peptide of 7 kDa in both cases (± ATP -preincubation). Sequence analysis of this peptide showed that in ATP-incubated CF 1 , tyrβ328 was modified with NBD-C1, whereas the ATP free sample contained no NBD bound to this tyrosine. Further digestion of the labelled peptide with protease V8 (Staphylococcus aureus) followed by sequence analysis of the radioactive labelled peptide, led to the detection of β-tyr362 as the modified amino acid in case of ATP-free CF 1 . Both tyrosines are closely related to a proposed nucleotide binding region of β

A hypothesis is presented concerning a putative extra-am yloplastic location of barley seed endosperm ADP-glucose pyrophosphorylase (AGPase), a key enzyme of starch biosynthesis. The hypothesis is based both on indirect and direct evidence obtained in our laboratory as well as on data of other investigators. It is proposed that ADP-glucose form ed by the extraamyloplastic enzyme is transported to the am yloplasts via an ADP-glucose carrier in the plastid membrane, and then is utilized by the starch biosynthesizing machinery of these organelles. In addition to the extra-am yloplastic form of AGPase, barley endosperm contains also a second isozyme of AGPase, located in the amyloplasts. Presence of isozymes of AGPase in cereal seed endosperm is consistent with biochemical, molecular and genetic data on starch biosynthesis in this tissue

The molar mass of photosystem I (PS I) from the cyanobacterium Synechococcus PCC 7002 was determ ined by sedim entation equilibrium analysis in the analytical ultracentrifuge. For that purpose, the “trimeric” form of PS I was isolated and studied in three different nonionic detergents. After determining the partial specific volume of the protein/pigment complex, from the ultracentrifuge data, as (0.788 ± 0.010) ml g -1 , M r was obtained as 830,000 ± 60,000

Recently we have shown that the autofluorescence within or just outside of a malignant tumor is rather small or large resp. in com parison to healthy tissue when excited at 365 nm. Studies with unfixed, unstained cryosections of skin with melanom as have revealed bulky fiber-like structures with a high fluorescence intensity just outside of a malignant tum or. Using polarized light, the structures could be identified as elastic fibers. This was also confirmed by studies on arterial walls

The cytochrome b gene of the Tawny Owl (Strix aluco), Hume’s Tawny Owl (Strix butleri) and the African wood owl (Strix woodfordii) was amplified by polymerase chain reaction (PCR) and partially sequenced (300 base pairs). Sequences differ substantially (9 to 12% nucleotide substitutions) between these taxa indicating that they represent distinct species, which is also implicated from morphological and biogeographic differences. Using cytochrome b sequences of S. aluco, S. butleri, S. woodfordii, Athene noctua and Tyto alba phylogenetic relationship were reconstructed using the “maximum parsimony” principle (PAUP 3.1.1) and the neighbour-joining method (MEGA)

We assessed the effects of 24 flavonoid derivatives, reported as anti-inflammatory, on lysosomal enzyme secretion and arachidonic acid release in rat neutrophils. Amentoflavone, quercetagetin- 7-O -glucoside, apigenin, fisetin, kaem pferol, luteolin and quercetin were the most potent inhibitors of β-glucuronidase and lysozyme release. The first com pound was also able to inhibit basal release. These flavonoids besides chrysin and to a reduced extent, naringenin, significantly inhibited arachidonic acid release from membranes. A correlation between degranulation and arachidonic acid release was found for this series of compounds. Structureactivity relationships and implications for the anti-inflammatory effects of these flavonoids were discussed

Human granulocytes exposed to pulsed electric guiding fields were investigated. The trajectories were determined from digitized pictures (phase contrast). The basic results are: (i) No directed response was induced by pulsed electric guiding fields having a zero averaged field, (ii) A directed response was induced by pulsed electric guiding fields having a non-zero averaged field, (iii) The directed response was enhanced for pulse sequencies having a repetition time of 8 s. (iv) The lag-time between signal recognition and cellular response was 8 - 10 s. The results are discussed in the framework of a self-ignition model

Deuteron spin lattice relaxation times T 1 of sucrose/D 2 O solutions are given as function of temperature, pressure, frequency and concentration. From the temperature dependence of the 2 H -T 1 the rotational dynamics of the hydrated sucrose complex and the water molecules are determined. For high pressure and high concentrations the temperature dependence of the water molecules is described by a Vogel-Tammann-Fulcher equation. The ideal glass transition temperatures T O H2O derived for the water molecules are at higher concentrations almost constant and smaller than the T O suc of the sugar molecules

The self diffusion coefficients D of the water molecules and of sucrose have been determined by the pulsed field gradient NMR technique over a wide range of temperatures and concentrations (c max : 70% w/w suc.). All temperature dependencies can be fitted to a Vogel- Tammann-Fulcher equation. The isothermic concentration dependence of D for the sucrose is given by a simple exponential concentration dependence

From Selaginella selaginoides the following three biflavonoids were isolated: amentoflavone, hinokiflavone and robustaflavone. The compounds were identified by means of spectroscopic methods

From Selaginella denticulata the following seven biflavones were isolated: amentoflavone, 7,4′,7″,4‴-tetra- O-methylamentoflavone, cryptomerin B, hinokiflavone, isocryptomerin, sotetsuflavone (7-O-methylamentoflavone) and robustaflavone

The root bark of Anthocleista nobilis is used in Nigeria against liver diseases, malaria and gastrointestinal worms. The secoiridoid pattern of the root bark was investigated. Sweroside and Anthocleistol a new secoiridoid have been isolated from the methanol extract. The structures were elucidated from spectroscopic data

The existence of a glassy state in isolated tomato fruit cuticles was investigated using differential scanning calorimetry. Tomato fruit cuticular membranes showed a glass transition temperature at -30 °C and an additional second order transition temperature near 30 °C. Changes in these temperatures during fruit growth were also studied

By means of gas chromatographic, mass spectrometric methods and combined GC-electroantennogramm techniques as well as activity comparison with pheromones of related species (3Z,6Z)-c/s-9,10-epoxyeicosadiene 1 and (3Z,6Z)-cis-9,10-epoxyheneicosadiene 2 were identified as the biological active components of the sex pheromone complex of the female arctiid moth Thyria jacobaeae