Volume 41, Issue 5-6

From Pseudomonas aeruginosa three siderophores belonging to the pyoverdine group have been isolated which differ only in the acid side chains bound to the quinoline chromophore.

Seven flavonoids were isolated from Hylocomium splendens (Hedw.). B. S. et G. The structures of two of them , the new biflavone 5′,3‴-dihydroxyrobustaflavone, a 5′,6″-C-linked biluteolin. and apigenin 7-O-(2,4-di-O-α-ʟ-rhamnopyranosyl)-β-ᴅ-glucopyranoside were completely elucidated.

Protocatechuic acid-4-, gallic acid-4-, caffeic acid-4-, ferulic acid- and p-coumaric acid-O-β-ᴅ-glucoside were synthesized. These substances were characterized by UV, 1 H NMR, 13 C NMR and FAB-MS. Their proportions in berry fruit and vegetable were determined by means of HPLC and capillary GC.

The surface waxes of five Euphorbia species (Euphorbiaceae) were studied by chemical methods and by scanning electron microscopy. The yields of epicuticular waxes, expressed as percentages of the dry weights, differed from species to species. Qualitatively the five species showed the same wax composition but differences appeared in the amounts of single wax components and in their distribution patterns. The predominance of mainly saturated and long chained components as well as the high amounts of primary alcohols and triterpenols resulted in crystalline wax layers. The comparable chemical wax com position of all five species resulted in a quite similar morphological appearance of wax crystals.

The existence of 1 N-acetyl-3-indolylm ethylglucosinolate in young seedlings of Tovaria pendula Ruiz et Pav. has been proven by HPLC and mass-spectrometric methods. This compound is accompanied by 4-hydroxy-glucobrassicin, glucobrassicin, 4-methoxy-glucobrassicin and neoglucobrassicin ( 1 N-methoxy-glucobrassicin).

The level of fructose-2,6-bisphosphate (F2,6BP), a potent regulator of carbohydrate metabolism , varied from 23 to 448 pmol·g fresh weight -1 during the growth of the cells of Catharanthusroseus in suspension culture. The maximum F2,6BP level was found in the cells at the lag phase of the growth, and its level decreased with cell division and enlargement.

The incorporation of [1,2- 13 C 2 ]acetate into the bacterial phytotoxin pyoluteorin (1) as determined by 13 C NMR spectroscopy occurs in a pattern consistent with the biosynthesis of the molecule as a tetraketide in which proline, or an equivalent precursor derived from the TCA cycle, serves as the starter unit.

The isovitexin-O-glycosylation patterns of rosette leaves, stem leaves and petals of Silene dioica plants were investigated. The 7-O -xylosylation of isovitexin, controlled by gene gX, only occurs in the petals. In the leaves isovitexin is 7-O -galactosylated, which is controlled by gene Xgal. Acyl groups may be linked to either the 7-O- or the 2″-O-substituted sugar; the former only occurs in the leaves, whereas the latter takes place both in leaves and petals. The restriction of the gX controlled enzyme activity and its product to the petals of Silene dioica plants is in complete agreement with previously obtained results (reference [2]) on the expression of g X in the genetic background of the closely related Silene pratensis, into which gX can be introduced by introgressive hybridization. On the basis of serological enzym e inhibition studies, it is argued that the absence of 7-O-xylosylation in the leaves is not due to post-translational inactivation of the gX controlled enzyme. The regulation of the expression of gene gX throughout ontogeny therefore differs markedly from that of two allelic g locus variants, controlling the 7-O-glucosylation of isovitexin.

Different fungi are discussed to play a certain role in recent spruce decline in addition to different abiotic factors such as SO 2 , photooxidants (ozone) or unfavourable climatic conditions. Thus, ergosterol as a specific fungal sterol was used as a biochemical indicator for fungal infection in differently damaged spruce and fir needles. With its aid it could be demonstrated that the important needle pathogens Rhizosphaera kalkhoffii Bubak, Lophodermium piceae and Sirococcus Type II contain unsaponified ergosterol comparable with the ergosterol content of different edible m ushrooms. Furthermore it could be shown that all necrotic and also certain bleached and green needles exhibit fungal infection. However, fungal invasion seem s to be a secondary reaction after the needle is predamaged by different factors.

Gleditsia triacanthos L. (honey locust), a plant of the widespread family Leguminosae, shows strong nyctinastic behaviour. Guided by the bioassay, a number of turgor influencing substances - PLMF 1, PLMF 3, PLMF 4, PLMF 5 and PLMF 6 - could be isolated and characterized from aqueous extracts of this plant. Structure and biological relevance of this phenolic-acid-glycosidesulfates are confirmed by synthesis. The multitude and the graduated biological activity of that factors suggests a biological way of irritation, who is after all responsible for the nyctinasty of G. triacanthos.

(Z)-9-Tetradecenyl methanesulfonate derived from (Z)-9-tetradecenoic acid (myristoleic acid) of beef tallow served as starting material for the preparation of sets of alcohols, alkyl acetates, and aldehydes having 16 and 18 carbon atoms. These com pounds are known to function as pheromones in various insect species. Chain elongation of (Z)-9-tetradecenyl methanesulfonate by malonic ester synthesis follow ed by esterification afforded the methyl ester of (Z )-11-hexadecenoic acid. This ester was converted to a set of pherom ones having a C 16 -chain with a (Z)-double bond in position 11. Chain elongation of (Z )-11-hexadecenyl methanesulfonate yielded the m ethyl ester of (Z)-13-octadecenoic acid which was used for the preparation of a set of pheromones having a C 18 -chain with a (Z)-double bond in position 13. All the reaction steps involved provided excellent yields.

The hypersensitive reaction in incompatible wheat-rust interactions is characterized by an increase in lipoxygenase activity detectable as early as 28 h after penetration of the pathogen. In contrast, lipoxygenase activity in the compatible interaction did not increase until the onset of sporulation. Lipoxygenase activity also increased following treatment of wheat leaves with an elicitor fraction from germ tubes of Puccinia graminis tritici.

Ammonia was excreted at high rates in the presence of L-methionine sulfoximine (L-MSO) from Chlorella cells which have been grown and analyzed at normal CO 2 partial pressure (330 ppm ). If these cells are analyzed at high CO 2 -concentration (3% CO 2 in air) only little ammonia is excreted in the presence of L-MSO. In the absence of L-MSO no ammonia is excreted under either condition. In agreem ent with this observation Chlorella cells grown under high CO 2 partial pressure (3% CO 2 in air) but tested under normal CO 2 partial pressure excreted only very little ammonia. Under these conditions neither “High CO 2 -cells” nor “Low CO 2 -cells” exhibited any glycolate excretion. However, glycolate excretion was observed in the presence of a-HPMS (a-hydroxy-2-pyridyl methanesulfonate) an inhibitor of glycolate dehydrogenase or INH (isonicotinyl hydrazide) an inhibitor of the glycine-serine am inotransferase, irrespective of the presence or absence of L-M SO. INH inhibited ammonia excretion. The above described high ammonia excretion in “Low CO 2 -cells” in the presence of L-MSO was suppressed or substantially reduced by 0.1 mм ethoxyzolamide an inhibitor of carbonic anhydrase which, however, at the same time caused a substantial excretion of glycolate into the medium. The same qualitative effect of ethoxyzolam ide was observed in “High CO 2 -cells” (tested under normal CO 2 partial pressure) although the amount of glycolate excreted in this type of culture was very small. It was generally noted that glycolate excretion caused by ethoxyzolamide was stoichiometrically always more important than the rate of ammonia excretion which was inhibited. This shows that excretion and therefore most probably also the formation of glycolate are enhanced by ethoxyzolamide. The experiments seem to show that due to the inhibition of carbonic anhydrase the affinity of the ribulose-1,5-bisphosphate carboxylase/oxygenase system is increased towards oxygen, which leads to a stimulation of the photorespiratory carbon cycle.

E. halochloris thylakoids and spheroplasts were treated with trypsin, thermolysin or proteinase K to determine which proteins are exposed at the different membrane surfaces. Based on SDS polyacrylamide analysis, all 9 polypeptides are exposed on the cytoplasmic side. Only one (28 kDa) is accessible from the periplasmic side. This polypeptide is generally isolated as the H-subunit of the reaction centers of photosynthetic bacteria, but is in the case of E. halochloris rather isolated with the antenna (B 800/1020) (Steiner and Scheer, Biochim . Biophys. Acta 807, 278, 1983). Proteolysis is accompanied by a shift of the absorption band at longest wavelengths from 1020 to 960 nm (B 800/960), which upon standing is shifted further to 680 nm (“B” 800/680). The spectral changes are similar to the ones reported earlier for treatment with acid, and are also inducible with urea. The correlation of SDS-PAGE and absorption spectroscopy shows, that the chroophores absorbing at 1020 nm are transformed sim ultaneously with the degradation of the 6.5 kDa (=α) polypeptide.

Seven protein kinases (PI-PVII) from maize (Zea mays) coleoptile homogenates could be detected which phosphorylate a histone-substrate in a polyacrylamide-matrix. The kinases PI, PII and PVI were stimulated by 6 μм cAMP, PHI, PIV and PV were cAMP independent, while PV II was inhibited by 6 μм cAMP.

The photosynthetic activities of barley leaves in vivo and of thylakoids, isolated from the leaves, in vitro were studied during greening in the presence or absence of 2 × 10 -4 м SAN 6706. The degree of chlorophyll bleaching increased from 32% at 24 h of greening to 60% at the final stage. Treated leaves were unable to carry out 14 CO 2 -fixation, their fluorescence induction properties showed very limited, if any, photosystem II-activity, and the thylakoids isolated from the leaves were also inactive in mediating ferricyanide Hill reaction. The leaves, however, exhibited lightinduced quenching of fluorescence revealed by slow fluorescence induction measurements; and the thylakoids were active in mediating photosystem I-specific in vitro Mehler reaction. Thylakoid membranes of the chloroplasts isolated from treated leaves contained CP 1 and LHCP 3 bands as revealed by polyacrylamide gel electrophoresis. From these results it is concluded that i) greening in the presence of SAN 6706 leads to the formation of inactive photosystem -II units; that ii) photosystem-I per se is active in vitro, and can, possibly, mediate cyclic electron transport in vivo coupled to the formation of ATP; and that iii) the presence of xanthophyll pigments is required for the assembly of the light-harvesting complex. The experiments were repeated with the application of SAN 9789, another pyridazinone compound, and yielded practically the same results as those obtained with SAN 6706. For practical reasons, only the results obtained with SAN 6706 are demonstrated throughout this communication.

In the gametophyte of the fern Anemia phyllitidis synthesis of linolenic acid esterified in monogalactosyldiglyceride requires light. By induction-reversion experim ents it could be demonstrated that this light-dependent step is mediated by phytochrome. There is also evidence for phytochrome control of galactolipid and hexadecatrienoic acid synthesis. In continuous blue light the synthesis of linolenic acid is inhibited and linoleic acid accumulates. It is concluded that the blue light photoreceptor affects an inhibition of linoleic acid desaturase. In continuous blue light chloroplasts contain abundant multilayered thylakoids, the grana regions are not as distinct as in white light, and membranes appear less appressed. In continuous red light the membranes are reduced in number and contain less grana-like appressions. It is concluded that both photoreceptors are necessary for a coordinate synthesis and assembly of the individual components of the chloroplast membrane.

The effect of different growth light intensities (60 W·m -2 , 6 W·m -2 ) on the performance of the photosynthetic apparatus of mustard plants (Sinapis alba L.) was studied. A distinct decrease in photosystem II content per chlorophyll under low-light conditions compared to high-light conditions was found. For P-680 as well as for O ᴀ and O в protein the molar ratio between high-light and low-light plants was 1.4 whereas the respective concentrations per chlorophyll showed some variations for P-680 and O ᴀ on the one and O в protein on the other hand. In addition to the study of photosystem II components, the concentrations of PQ, Cyt f, and P-700 were measured. The light regime during growth had no effect on the amount of P-700 per chlorophyll but there were large differences with respect to PQ and Cyt f. The molar ratio for Cyt f and PQ between high- and low-light leaves was 2.2 and 1.9, respectively. Two models are proposed, showing the functional organization of the pigment system and the electron transport chain in thylakoids of high-light and low-light leaves of mustard plants.

The cytochrome P-450 dependent monooxygenase system of rat liver microsomes is investi- gated by light dosimetry (action spectroscopy). The scoparone-O-demethylation activity is en- hanced by light and depends on the wavelength of the irradiating light. The relative increase of the activity (about 15%) by the irradiating light (~ 0.5 mW/cm 2 ) is maximal at a wavelength of 400 nm. The light induced enhancement of the 7-ethoxycoumarin-O-deethylase activity was measured in reconstituted systems, consisting of one of the two P-450 enzymes (P-450 βNF-B and P-450 PB-B ) with the NADPH-cytochrome P-450 reductase. The action spectrum of the reconstituted P-450 βNF-B : NADPH-P-450 reductase complex shows a maximum between 420 and 440 nm. The relative increase of the activity induced by light of 420 nm was 7.3% and 9% for the reconstituted systems of P-450 βNF-B and P-450 PB-B . respectively. The results are discussed in analogy to the classic experiments of Warburg with its blocked CO- enzyme-complex. The results can best be explained by the assumption that the light induced enhancement of the enzyme activity is due to an excitement of those intermediate states of the P-450 catalytic cycle (ferric and ferrous state of the heme iron) which are rate limiting.

Three 17-residue peptides, presenting from 65% to 70% sequence homology, and one endecapeptide, with no apparent homology with the first three, were chemically synthesized and investigated in their ability to elicit rabbit antipeptide antibodies. The complex crossreactivities of the antisera were investigated by testing the binding of the antibodies to the intact peptides, to their enzymatic fragments, and by the use of specific immunoadsorbents. Antipeptide antibodies may or may not crossreact with related “parent” peptides, this depending upon number, distribution, and localization of amino acid differences in low or high antigenicity regions of the immunogen. Related peptides may elicit antibodies that crossreact almost completely, and therefore not specific for one or the other “parent” peptide. Those the selective recognition of closely related structures.

The crystal structures of the title compounds which display cholinergic activity at the ganglionic receptor have been determined by X-ray structure analysis. [(CH 3 ) 3 N + C 5 H 11 ]Cl - (1) crystallizes in the orthorhombic space group Pbnm with half a formula unit per asymmetric unit, a = 11.381(14). b = 12.871(17), c = 7.316(4) Å. The intensities of 1106 independent reflections were collected with an automatic diffractometer. The structure refinement converged at R = 0.133 for the 355 observed reflections. The cation of 1 is disordered. [(CH 3 ) 3 N + (CH 2 ) 4 -O-C(O)-CH 3 ]I - (2) crystallizes in the orthorhombic space group P2 1 2 1 2 1 with four formula units per unit cell, a = 16.783(8), b = 10.276(6), c = 7.427(10) Å. The intensities of 1469 independent reflections were collected. The structure refinement converged at R = 0.071 for 1383 observed reflections. In both compounds the trimethylammonio methyl groups are coordinated nearly tetrahedrally by four anions in the first coordination sphere. Anions which occupy a special face type (B) of the tetrahedron of the (CH 3 ) 3 N + -CH 2 -group may be treated as a “model binding site” of the receptor. In the crystal structure of 2 the anions occupying B-type faces form together with the ammonium nitrogen and the carbonyl oxygen so called “Activity triangles”. The almost equal geometries of these activity triangles are correlated with the mode of pharmacological action.

General features of crystal structures of halide salts of cholinergic stimulants can be interpreted in terms of substrate-receptor interactions. The monoatomic counterions in the crystal structures are discussed as models for the binding site of the receptor with respect to the ammonium group of the cholinergic neurotransmitters. In the crystal structures the anions occupy the tetrahedral faces of the quaternary trimethylammonio methyl or related groups in a specific geometry. Crystallographic and pharmacological evidence indicates that these groups should preferentially interact with the receptor via a specific face type (B-type face). The directionality of the interaction is derived from the vectors joining N + with the anions occupying B-type faces. So called “activity triangles”, formed by the nitrogen of the ammonium group, a second polar centre of the neuro-transmitter cation and a counterion occupying a B-face of the ammonium group, provide a structural criterion for the differentiation between muscarinic and nicotinic activity. It is shown that structure-activity relationships of cholinergic stimulants do not depend on the conformational details of the neurotransmitter cations, but primarily on the relative positions of the polar centres of the cations with respect to the anionic binding site of the receptor.

The title compound (1) crystallizes in the orthorhombic, noncentrosymmetric space group Pna2 1 with a = 10.241(11), b = 12.903(12), c = 9.312(9) Å and with one formula unit per asymmetric unit. The stereochemically comparable torsion angles of the cation of 1 and of acetylcholine chloride are analogous. In the crystal structure the trimethylammonio methyl group is surrounded by three anions in the first coordination sphere. The geometry of a triangle formed by one of these counterions which occupies a special face of the N + C 4 tetrahedron of the (CH 3 ) 3 N + -CH 2 -R moiety, the nitrogen atom of the ammonium group and the oxygen atom of the carbonyl group is typical for nicotinic agonists.

The blockage of all thiol residues accessible to the mercurial mersalyl in the sarcoplasmic reticulum membranes resulting in complete inactivation of the membranes’ calcium transport system does interfere neither with caffeine- nor calcium-induced calcium release from actively loaded membrane vesicles.

The ability of calcium lo ad ed heavy sarcoplasmic reticulum vesicles to specifically respond to the addition of various agents such as caffeine, calcium ions and calmodulin antagonists to rapidly released calcium can largely be diminished by passing the vesicular suspension in 0.3 м sucrose, 0.6 m KCl, 4 mм C Cl 2 , pH 7.0 through a Sepharose 6 B column or by centrifuging it through a sucrose gradient prepared with the same salt medium. Inactivation of calcium release does neither interfere with calcium uptake nor with the unspecific releasing effect caused by the application of high concentrations of calmodulin antagonists.

The time course of the recovery of the sensitivity of the Limulus ventral nerve photoreceptor was measured during dark adaptation following light adaptation by a bright 1 or 5 s illumination. The stimulus intensity I CR of a 300 μs light flash evoking a response of criterion amplitude (receptor potential or receptor current under voltage clamp conditions) was used as measure of sensitivity. The time course of dark adaptation shows two phases with time constants in the range of 5-9 s and 300-500 s (15 °C). Only the first of the two phases is significantly changed when the extracel- lular Ca 2+ -concentration is varied. The power function I CR = a·I o -t DA -b gives a good data fit for each of the two phases of dark adaptation. In the first phase the factor a x and the exponent b x are decreased when the external calcium is lowered from 10 mmol/1 to 250 μmol/1. Conversely a 1 and b 1 are increased when the Ca 2+ -concentration is raised to 40 mmol/1. For the second phase neither a 2 nor b 2 is changed significantly upon the changes in calcium concentration in the same experiments. The two phases of dark adaptation reflect the behaviour of the two components C 1 and C 2 of the electrical light response (receptor potential or receptor current). Under the conditions described here C, determines the size of the light response during the first phase of dark adaptation whereas C 2 mainly influences the size of the response during the second phase. Interpretation: The fast first phase of dark adaptation is determined by the change in intracellu- lar Ca 2+ -concentration. The slower second phase of dark adaptation is not primarily calcium- controlled.

Three immune sera, raised in rabbits against synthetic peptides corresponding in sequence to predetermined regions of the HLA-DQ histocompatibility antigens, were tested for their ability to recognize phenotypicallv distinct human lymphoblastoid cell lines. The immune sera readily recognize the immunogen. When tested on the cells, they react poorly but seem to exhibit a certain degree of specificity. The possibilities in developing true selective reagents for HLA-alloantigens are considered and discussed.