Volume 44, Issue 9-10

Broths extracts of the fungus Sordaria macrospora afforded new hexaketides related to sordariol: sordarial, the corresponding aldehyde, heptacyclosordariolone and cyclosordariolone, two cyclic compounds. The structure of these substances has been established by spectrometric methods.

The isoflavone aglycone kwakhurin hydrate, and the glycosides genistin (genistein-7-Oglucoside) and puerarin-6′′-monoacetate have been isolated from a methanolic extract of Pueraria mirifica roots.

Several lipophilic phenolics were found in leaf resins of Baccharis species, reported earlier to produce terpenoids and flavonoid aglycones. They were identified by NMR and GC/MS studies, respectively. The structure of 2′,4′β-trihydroxy-6′-methoxychalcone from B. salicifolia was confirmed by synthesis. Phenylethyl caffeate and benzyl caffeate were found in B. sarothroides.

The leaf, seed shell and seed coat epicuticular waxes of beech (Fagus sylvatica L.) contained the following common wax lipids: alkanes, wax esters, aldehydes, primary alcohols and fatty acids, all occurring in a homologous series of very long chained and saturated components with variations in the maxima in each homologous series. In addition, small amounts of benzylacyl esters in leaves, and ketones in seed shells and coats were also found in homologous series. β-Sitosterol was present only in seed shells and coats. Free primary alcohols (34.8%) were found to be the major class in the leaves whereas free fatty acids were predom inant in seed shells (39.5%) and coats (42.1% ). The beech organs studied showed always a specific wax composition.

The lipid composition of beech (Fagus sylvatica) seeds is reported in the present study. Triacylglycerols (94.8% ) were found to be the major component in the oil followed by sterols (0.9% ) diacylglycerols (0.8% ), phospholipids (0.7% ), free fatty acids (0.5% ) and monoacylglycerols (0.3% ) in minor quantities. The composition of molecular species of triacylglycerols was analyzed by GC on the basis of chain length and C-57 was found to be the major species followed by C-55, C-59, C-53 and C-61. The sterol fraction constituted β-sitosterol and stigmasterol with 89.3 and 10.7% respectively. Phosphatidylinositol and phosphatidylethanolamine were the two phospholipids with 55 and 45% present in the phospholipid fraction of the beech seed oil. Oleic, linoleic and palmitic acids were found to be the major fatty acids in all the acyl lipid classes with small variations in quantities.

The lipid composition of Piqui (Caryocar coriaceum) seed oil and pulp oil was analyzed and found to contain triacylglycerols (95.1/95.3%) as major components followed by free fatty acids (1.7/1.6%), diacylglycerols (1.6/1.5%), squalene (0.3/0.3%) and monoacylglycerols (0.1/0.1%). Phospholipids were found only in seed oil (0.2%). They were identified as phosphatidylethanolamine and phosphatidylinositol. The sterol fraction (0.1/0.1%) contained stigmasterol and β-sito-sterol. In seed oil triacylglycerols the C-53 molecular species were dominated (52.8%) follow ed by C-55 (37.7%), C-57 (6.9%) and C-51 (2.6%) in minor quantities. In pulp oil triacylglycerols C-55 (51.7%) was predominant followed by C-53 (30.6%) and C-57 (17.7%). Palmitic (16:0) and oleic (18:1) acids were always the major fatty acids in both oils. In seed oil their quantities were nearly the same, whereas in pulp oil oleic acid was predominant. Composition of Lipids of Piqui (Caryocar coriaceum Wittm.)

The fatty acid composition in the lipids of six coccoid microalgae species (≈ 2 μm in diameter) was investigated. In addition to analyses of ultrastructure and pigment content, lipid composition is shown to be a chemotaxonomic tool in the classification of algae. The four species of Chiorococcales (Chlorophyceae) - the marine species as well as the fresh water species, both kept in artificial seawater - contain a fatty acid composition resembling that of Chlorella spp. and of green leaves of higher plants. The fatty acid pattern is characterized as lacking in C20 acids but containing large amounts of C 16 and C 18 polyunsaturated fatty acids, hexadecatrienic acid (16 :3) and a-linolenic acid (18:3ω3) in particular. In contrast the two species of Eustigmatales (Eustigmatophyceae) investigated here show a deficiency of the C 16 and C 18 polyunsaturated fatty acids but contain large amounts of eicosapentaenic acid (20:5).

The lipoprotein-peptidoglycan complex (rigid layer) from Rhodobacter sphaeroides was isolated. Treatment of the complex with N.O-diacetyl-muramidase cleaved off from the rigid layer the lipoprotein moiety with covalently bound peptidoglycan-fragments. The lipoprotein with the bound fragments showed a broad single band (M r about 19,000) on SDS-polyacrylamide gels and had an isoelectric point of about 5.6. There was no serological cross-reaction with the rigid layer of Escherichia coli K12. The lipid moiety of lipoprotein with residual amino acids (mainly Gly, Ser, Gly, Asp) was obtained by Pronase E treatment of the rigid layer and chloroform -methanol extraction. It was free from phosphate and contained amide- and esterbound 18:1 and esterbound 16:0 and 18:0. The isolated peptidoglycan, after enzymatical cleavage from the lipoprotein, had a chemical composition indicating Aly-type structure. Comparable studies, performed with Rhodobacter capsulatus 37b4 resulted in essentially similar results for rigid layer, lipoprotein and peptidoglycan compositions.

The activities of some of the glycosidases in cell walls were measured during the cell cycle in a synchronous culture of Catharanthus roseus (L.) G. Don. The salt-extractable α-galactosidase activity increased during the G 2 phase, whereas β-glucosidase and β-galactosidase activities in cell walls increased during the G 1 phase after cytokinesis.

Phytochrome was isolated from etiolated rice seedlings (Oryza sativa L.) by slight modification of the procedure for oat phytochrome. Spectral data of rice phytochrome are comparable with those of oat and rye phytochrome. Controlled proteolysis with endoproteinases Lys-C and Glu-C yielded defined fragments some of which were different for Pr and Pfr. The fragments were identified by comparison with the corresponding fragments of oat phytochrome and by comparison of the amino acid sequences of rice and oat phytochrome. Regions of the peptide chain which are differently exposed in Pr and Pfr were identified. A highly conserved sequence around residues 740-750 is discussed as candidate for an ‘‘active center’’ of signal transduction.

Various mono- and disubstituted cinnamic acid derivatives and aromatic carboxylic acids with saturated side chains were incubated mainly with Bacillus, Candida, Hansenula, and Saccharomyces strains. The cinnamic acids carrying a hydroxy- and/or a methoxy group at the 3- and/or 4-position of the benzene ring were decarboxylated with high yields. Most of the reactions were terminated within 24 to 48 h. Substitution at other ring positions afforded also decarboxylation, but at much lower yields. Derivatives with other residues like methyl, chloride, or bromide were not transform ed to the respective styrene. None of the saturated aromatic carboxylic acids could be decarboxylated by the strains used.

Ten strains of Ascochyta rabiei pathogenic to chickpea ( Cicer arietinum L.) were shown to be potent degraders of the chickpea pterocarpan phytoalexin ( - )-maackiain (1) ([6aR: 11 aR]-3- hydroxy-8,9-methylenedioxypterocarpan). In degradative studies with mycelial preparations and crude protein extracts seven catabolites could be isolated and structurally elucidated by spectroscopic techniques. The main routes of maackiain degradation are reduction to a 2´-hydroxyisoflavan (2) and oxidation to an 1 a-hydroxy-pterocarp-1,4-diene-3-one (3) with subsequent reductions of the early catabolites in ring A. A catabolic sequence for maackiain is compared with the degradation pattern of pterocarpan phytoalexins observed with other fungi.

Boron and silicon have a dramatic influence on the expression of symptoms caused by plant virus infections. For tobacco plants, boron decreases and silicon enhances symptom expression after belladonna mottle virus infection. Infected leaf tissues are highly enriched on both trace elements. Boron supply stimulates the silicon accumulation. In the applied concentrations the trace elements have no phytotoxic effects on the host. Except endogeneous β-interferones, this could be the first example of antiviral action without any cytotoxicity.

An optimal supply of biodisposable silicon and boron shows a synergistic stimulation effect on plant growth. Under these optimal growth conditions herbicides may become particularly toxic for cultural plants. Plants inhibited by herbicides show distinctly higher boron contents than that of untreated samples.

Bleaching herbicides inhibit carotene biosynthesis in photosynthetic organisms. The interaction of norflurazon [4-chloro-5-methylamino-2-(3-trifluoromethylphenyl)-pyridazin-3(2H)one] with its target enzyme phytoene desaturase, has been characterized by enzyme-kinetic studies. A Lineweaver-Burk plot showed a non-competitive m anner for norflurazon inhibition. Binding of norflurazon to phytoene desaturase was reversible as dem onstrated by complete replacem ent of bound 14 C-labeled herbicide by unlabeled norflurazon. In a linear Dixon plot the k i value for norflurazon was determ ined as 0.09 μм . With the in vitro system from Anacystis used in this study it was possible to perform structure-activity studies with selected m -phenyl-substituted pyridazinones. A linear relationship between inhibitory properties of these compounds and their lipophilicity could be established.

The colony forming ability of E. coli mutants defective in DNA repair was compared to that of the parent strain AB 1157 after neocarzinostatin treatment. A recA and a recB mutant were most sensitive. The suppression of the recB mutation in the recBC sbcBC mutant, which is as sensitive as the parent strain, indicates that recB is not the primary pathway by which lesions after NCS treatment are repaired. The survival curve of the recBC recF sbcBC mutant, corresponding to that of the recF mutant, further supports this interpretation. The relative resistance of the recBC recF sbcBC mutant suggests that NCS lesions are not only repaired by the recF and recB pathway. An alternative pathway could be the SOS induction, as a lexA m utant also is sensitive to NCS. The sensitivity of the uvrA and polA xthA mutants, however is explained by the involvement of the uvrA and polA gen products in rec repair.

Actinoplanes missouriensis utilizes arogenate as an intermediate in ʟ-tyrosine biosynthesis, while no evidence of prephenate dehydrogenase was observed. Arogenate dehydrogenase has been partially purified by a five-step procedure. The enzyme requires NAD as cofactor. The K m values for NAD and arogenate are 0.2 mм and 0.15 mм, respectively. The molecular weight of arogenate dehydrogenase is about 68,000, and SDS gel electrophoresis indicates a composition of two identical subunits. The enzyme is not feedback inhibited by ʟ-tyrosine and unaffected by ʟ-phenylalanine, prephenate, phenylpyruvate, p-hydroxyphenylpyruvate or ʟ-tryptophan. Arogenate dehydrogenase is quite sensitive to p-hydroxymercuribenzoate with 50% inhibition at 12.5 μм of the SH -specific reagent. The presence of malate in usually applied arogenate preparations is demonstrated and the consequence of an impure substrate on arogenate dehydrogenase studies is discussed.

In order to analyze the effects of inorganic phosphate (Pi) on the energy metabolism of suspen­sion-cultured cells of Catharanthus roseus, short-term changes in levels of glycolytic metabolites were monitored after the addition of 1.25 mм Pi to cultures of cells previously cultured in a Pi-free Murashige-Skoog medium for 24 h. The levels of all phosphorylated intermediates of glycolysis examined were found to increase after addition of Pi. The most striking increases were observed in levels of glucose-6-phosphate and fructose-6-phosphate which rose to approximately 8 (after 30 min) and 15 times (after 120 min) their initial values. The levels of ATP and pyrophosphate doubled during the first 30 min of incubation. In contrast, the level of pyruvate decreased significantly during the initial 30 min and then began to increase again for the next 90 min. The short­ term effects of Pi on the rates of synthesis of proteins and RNA were estimated from the rates of incorporation of 14 C-labelled amino acids and uridine into the macromolecules. No appreciable stimulation of the synthesis of proteins and RNA was induced by Pi within 120 min after the addition of Pi. Possible mechanisms are discussed that may be involved in the changes in metabo­lism initiated by the addition of Pi to the cultures.

The effects of 25-hydroxy-vitamin D 3 (25 OHD 3 ) on myoblast protein synthesis were studied in connection with its role on muscle cell phosphate metabolism . The sterol markedly increased leucine incorporation into total cell proteins in cultured chick embryo myoblasts. This enhance­ment was greater than that produced by 1,25-dihydroxy-vitamin D 3 (1,25(OH) 2 D 3 ) and occurred prior to a significant stimulation of cell phosphate accumulation. Maximum effects of 25 OHD 3 (8 h) on myoblast phosphate uptake were suppressed by cycloheximide indicating that they are mediated by de novo protein synthesis. At a similar treatment period, labelling of myoblasts with [ 3 H]leucine (control) and [ 14 C]leucine (+ 25 OHD 3 ) followed by co-electrophoresis of total protein extracts on SDS-PAGE and isoelectrofocusing gels revealed that the sterol selectively affects the synthesis of proteins of 20 kDa and 50 kDa. These macromolecules were recovered in the microsomal fraction after differential centrifugation of homogenates. Further fractionation of myoblast microsomes on sucrose density gradients show ed co-localization of the 50 kDa and 20 kDa proteins with microsomal subfractions which preferentially bind [ 3 H -alpha]bungarotoxin, suggesting that the proteins induced by 25 OHD 3 are associated to plasma membranes and may play a role in the effects of the sterol on cell phosphate uptake.

Antibodies against HLA Class II alpha chains were prepared by using as immunogens synthetic peptides selected from the HLA -DQ 1 alpha chains sequence. Antibodies raised against peptide E2 , a 15-residue fragment of the polymorphic first domain, reacted preferentially with cells with the DQ 1 phenotype; however, despite the low sequence homology of this fragment with corresponding segments in DQw2 and DQw3 alpha chains, a partial crossreactivity with cells not expressing the DQw 1 specificity was detected. Antibodies to peptide H , selected from the monomorphic frame, might be specific for DO alloantigens, and presumably do not react with DR antigens. The two peptides, in addition, bind anti-Class II antibodies from the serum of a rabbit immunized with human cells, and appear to represent immunogenic linear determinants in the native glycoprotein molecule.

Although oxygen dependent photoreactions of 8-methoxypsoralen (8-MOP) are known, damage to DNA is mostly considered to proceed via photocycloaddition to this biomacromolecule. In this study the survival of colony forming ability of E. coli K 12/343, which is deficient in DNA-repair capability, appeared to be lower in D 2 O than in H 2 O after exposure to the combination of 8-MOP and UV-A . Photobinding to bacterial DNA was ∼40% higher in D 2 O than in H 2 O. How ever this last difference was found only when the bacteria were kept in the reaction medium for 1 h at 37 °C after the irradiation was stopped and not when they were plated out immediately afterwards. The results indicate that in this bacterial test system 1 O 2 mediated photobinding of 8-MOP to DNA contributes to the genotoxic effect observed.

The kinetic behavior of the spin label MAL-6 in the interaction with differently aged human erythrocyte membranes was evaluated by monitoring the rate of disappearance of the room temperature ESR signal due to the MAL-6 spin label added to blood after storage at 4 °C or after incubation of red cells at 37 °C in a protein-free medium. After 35 days of blood storage or 60 h of erythrocytes incubation at 37 °C the decrease of the intensity of the MAL-6 ESR spectra in respect to control samples is markedly enhanced and the correspondent kinetic constants significantly increase. Signal decay of MAL-6 is a further proof that during storage of blood under blood bank conditions or during an artificial ageing of erythrocytes at 37 °C, profound modifications occur in the human erythrocyte membrane.

The conformation of the two algal pheromones ectocarpene (1) and multifidene (2) was studied by the active analogue approach using molecular mechanics calculations within the software package SYBYL. A common conformation for both pheromones and all active analogues was filtered out by superposition- and energy minimizing procedures starting from crystallographic data of the Cambridge Structural Data Base (CSD). The interaction of the algal receptor systems with their olefinic pheromones and heteroanalogues is in excellent agreement with the assumption of a receptor-bound metal cation acting as the binding side.

The viability of three isogenic relA + /relA strain pairs of Escherichia coli (CP78/CP79; NF 161/ NF162; CP 107/CP 143) was studied during prolonged starvation for amino acids, glucose or phosphate. After amino acid limitation we found a prolonged viability of all relA + strains which synthesized ppGpp. We suggest that some ppGpp-mediated pleiotropic effects of the stringent response (e.g. glykogen accumulation, enhanced protein turnover) might be involved in this prolongation of survival. After glucose or phosphate starvation there was no difference in the relA + /relA strains either in the ppGpp content or in the survival.

A new method and a new type of measuring-microchamber for the investigation of cellular dielectrophoresis is presented. The method is based on the observation of the trajectory of a single cell in gravitational and electric fields being crossed and orientated perpendicularly to the observation direction. By means of this method the whole dielectrophoretic spectrum ranging from negative to positive dielectrophoresis may be easily and quickly obtained. The experiments carried out on different cell types showed that the dielectrophoretic spectra, as well as the dependence of the critical frequency upon medium conductivity and cell size agree well with the predictions of a new model of the dielectrophoretic mechanism proposed by Sauer.

After irradiation of single crystals of barbituric acid with X-rays at 77 K different types of radical pairs are found, which are com posed of only one type of monoradical. The properties of radical pairs of the unpaired electrons are studied using frequency-variable ESR methods at various temperatures. In addition to the radical pairs AD and BC two further pairs A′D′ and XY were identified. Measurements of the fine structure parameter D showed a linear temperature dependence in some regions between 77 K and 290 K. At 240 K the radical pairs AD and A′D′ changed reversibly into A*D* and this pair remained stable up to 290 K. A level anticrossing effect was observed with the pair AD. The exchange energy J between the singlet state and the triplet state was determined as -(15.1 ± 0.6) GHz at 77 K and its temperature coefficient as -(3.8 ± 0.8) × 10 -3 K -1 .

Using the technique of pulse radiolysis, it has been demonstrated that thiyl radicals (RS˙) derived from glutathione (GSH), cysteine (CYSH), penicillamine (PnSH) and 2-m ercaptoethanol (M E) interact with oxygen at a high rate. The resulting transient absorption, with a maximum around 540-560 nm, is characteristic of the sulphur peroxyl radical (RSOO˙). The yield and the kinetic of formation of RSOO˙ further support our previous suggestion that thiyl/O 2 reaction is an equilibrium. The redox properties of RSOO˙ are discussed on the basis of the interaction with reductants. Studies on the radio-induced enzyme inactivation in the presence of thiols seem to suggest a damaging role for RSOO˙ radicals.

The microwave influence on the growth of yeast cells is studied in a novel experimental set-up designed to observe individual cells growing for several division cycles. The results are in accordance with resonant microwave-induced growth stimulation as observed in our earlier set-up where the turbidity of a stirred suspension of cells was used as the measure of growth. The new experimental set-up is suited to decide on the proposed triplet mechanism of resonant microwave biological effects.

It is shown that light elicits distinct responses from cells in the fly’s eye which are different from photoreceptors. These cells are designated as “slow cells” because of their sluggish response characteristics. Like the visual cells the slow cells depolarize upon light stimulation, but the time course of their responses is clearly different from that of the photoreceptors. Furthermore, the intensity necessary to evoke a given response amplitude is considerably higher in slow cells than in photoreceptors. Several lines of evidence indicate that the slow cell response is caused by light absorption through the visual pigment rhodopsin in the peripheral photoreceptors R 1 -6. The slow cells are electrically coupled among each other, as demonstrated by application of local light stimuli and injection of the fluorescent dye Lucifer Yellow . The identity of the slow cells and the mechanism of response generation are discussed.

Treatment of Stentor with very acid culture medium (pH 2.8) results in delamination of the cortex from the endoplasm . This procures the possibility to strip off the cortex with all its acid resistant organelles at minimum loss of endoplasm. Acid sensitive organelles react with dissolution or more or less damage. The endoplast may survive giving rise to a thin plasma membrane, which may be (even several times) shed and renewed. 10.5% of the decorticated cells regenerated a complete cortex. The ball-shaped and apparently apolar endoplast may pass through an ameboid stage. The visible part of the regeneration process begins with the appearance of a chaotic line system , which in regaining the polar order turns out to be the pigment free interstripe spaces. The ubiquitous appearing of foot anlagen underline the apolar situation. Nevertheless, the problem of endoplasmic preservation of polarity requires further, presently running, experiments. Obvious polarity begins to restore with the development of first membranelies and - approximately in opposite position with these - the definitive foot develops with the holdfast organelle. The ordering of stripe pattern starts from the foot and proceeds to the cells apex. With respect to Tartar’s contradicting result (death o fall decorticated cells) the new experiments do not refute Tartars conclusions, since the technique is different from his only micro-surgical method. This will be discussed in a following paper in context with the results of some other experiments. The here described total regeneration of the cortex in Stentor is not consummated as cytotactic differentiation depending on preformed structure.

In cucumber cotyledons, both C 6 - and C 9- aldehyde were formed via hydroperoxide (HPO) lyase activity. Because it has not been elucidated whether these activities are attributed to one enzyme which can cleave both 13-and 9-HPO or to two or more enzymes each of which specifically cleaves 13-or 9-HPO , an attempt to separate HPO lyase activity was done. Ion exchange chromatography separated this activity into two fractions, one of which specifically cleaved 13-hydroperoxylinoleic acid and the other specifically cleaved the 9-isomer. 13-HPO-specific activity was most active at pH 8.0 and 9-HPO-specific one was at pH 6.5. SH -reagents inhibited both the lyases but to different extents.

This study indicates that antibodies raised against a DR4 , w6; DQw 1,3 positive cell line may bind to synthetic peptides selected from the polymorphic amino acid se­quences 51 -59 and 63 -79 on the DQw 2 beta chain. This cross-reaction may be explained by the relatively high sequence homology of these sequences in the beta chains of class II histocompatibility antigens, and suggests that anti­ body binding to small peptides may be scarsely selective. Based on the observations of the reactivity of the anti­ bodies with several cell lines, and comparison of the amino acid sequences of beta chains of DR and DQ molecules, an attempt to identify the cross-reacting epitope is presented.