Volume 48, Issue 5-6

From the temperature and concentration dependence of the 13 C spin lattice relaxation times of the 12 carbon atoms of the sucrose molecule the rotational dynamics of the sugar molecules are determined. No indication for conformational mobility of the rings is found. The exocyclic hydroxymethyl groups possess extra mobility. The models used for the description are critically discussed. The temperature dependence of the rotational mobility is described by a VTF equation. The concentration dependence of the ideal glass transition temperature T o for this mobility is derived.

Alkaloid extracts of leaves and seeds of the South American taxon Lupinus albescens Hooker & Arnott were analyzed by capillary gas-chromatography (G LC ) and G LC-mass spectrometry. Multiflorine and albine figured as major, and ammodendrine, lupanine, 11,12-seco-12,13-didehydromultiflorine 13a-hydroxyultiflorine and 13-tigloyloxymultiflorine as minor alkaloids. Three new alkaloids were tentatively identified as a dehydromultiflorine, N -formylalbine and 13-methoxymultiflorine.

Caffeoyltartronic acid and other eleven phenolic com pounds were identified in the MeOH extract of Chondrilla juncea: the flavonoids luteolin, luteolin-7-glucoside, luteolin-7-galactosylglucuronide and quercetin-3-galactoside; the phenolic acids protocatechuic, caffeic, chlorogenic, isochlorogenic and isoferulic and the coumarins cichoriin and aesculetin. The taxonomic im plications of these com pounds have been discussed.

Anaphalis margaritacea, Gnaphalium chilense and G. microecephalum have been analyzed for flavonoid aglycones deposited externally on aerial parts. Anaphalis was found to produce, among others, several rare flavonoids, all of which are O-substituted in position 6 and mostly also in position 8. Both Gnaphalium species exhibit 3,5-dihydroxy-6,7,8-trim ethoxyflavone as the major exudate flavonoid.

From a genetically manipulated strain of Pseudomonas aeruginosa ATCC 15692 (PAO 1 strain) a compound named pseudoverdin, 3-formylamino-6,7-dihydroxycoumarin, was obtained which is related to the typical pyoverdin chromophore and thus allows to shed some light on the biogenesis of the latter.

The structures of the two pigments in the red Cineraria, Senecio cruentus, flowers have been identified as malonylcaffeylcyanidin 3,3′-diglucoside (2) and as its demalonyl compound (1), new anthocyanins, by using chromatographic and spectroscopic techniques involving UV-VIS, IR, FAB-MS and NMR . In a neutral aqueous solution, the acylated anthocyanins retained their colorings for a long time.

Cuscuta reflexa, Lupinus angustifolius, Quinolizidine Alkaloids, Parasitism During parasitism on Lupinus angustifolius the phanerogamic parasite Cuscuta reflexa takes up quinolizidine alkaloids from L. angustifolius via haustoria that tap xylem and phloem ves­sels of the host. The alkaloid pattern of the haustorial region of C. reflexa as revealed by GLC as well as by GLC-M S closely resembles that of infested lupin stems. With increasing distance from the haustoria towards the apex of C. reflexa the complex alkaloid pattern of the host is significantly reduced. Whereas alkaloid esters such as 13-benzoyloxylupanine and 13-cinnamoyloxy-lupanine are prominent peaks in the alkaloid profiles of the host as well as of the haustorial region of the parasite they are not detected in the apex of C. reflexa but are replaced by their respective alcohol com ponent 13-hydroxylupanine. This change of alkaloid profiles is accompanied by a strong decline of alkaloid concentration which drops from ap­ proximately 11 m g/g dry wt. in the haustorial region of C. reflexa to 0.2 m g/g dry wt. in the apex. Alkaloid analyses of xylem sap and phloem exudate from L. angustifolius suggest that uptake of host plant alkaloids by C. reflexa is mainly via the phloem even though a contribu­tion of xylem sap to the supply of alkaloids to the parasite can not be excluded.

We solubilized from radish membranes and purified by 154-fold 3-hydroxy-3-methyl-glutaryl-CoA lyase (HMGL, EC 4.1.3.4) catalyzing the conversion of 3-hydroxy-3-methyl-glutaryl-(HMG -)CoA into acetyl-CoA and acetoacetate. The apparent molecular mass under non-denaturating conditions is 70 kDa. The enzyme has a broad pH optimum around 8.0 and its activation energy as determined from the linear part of an Arrhenius plot is 137.1 kJ/mol. The K m with respect to (5)-H MG-CoA is 40 μM . The enzyme is extremely unstable and rapidly loses activity even when kept on ice, but retains some activity over several weeks when stored at -80 °C.

Three strains of bacteria reducing (trifluoroacetyl)ferrocene (3) to optically pure (R)-2,2,2-trifluoro-l-hydroxyethylferrocene (4) and one bacterial strain reducing 3 to (S)-4 of moderate optical purity were isolated from sea-water collected at the coastal areas in Ibaraki prefecture of Japan. The former three strains were identified as Micrococcus lylae, Micrococcus luteus, and Deleya marina and the latter as Bacillus licheniformis. These strains also asymmetrically reduced some other synthetic ketones, e.g., 2,2,2-trifluoroacetophenone (7) and phenyl trimethylsilyl ketone (9). Further screening of microorganisms capable of reducing 3 was done with bacteria isolated from sea-water of the deep sea (Okinawa trough, Japan trench, and Mariana trough) and of the pelagic areas (Indian Ocean and South China Sea). Most of these marine strains preferentially reduced 3 to (R)-4 similar to the coastal strains, but the frequency of finding very highly enantioselective strains (i.e., those forming 4 of > 90% e.e.) was remark­ ably high in several sites of the deep sea and pelagic areas as compared with the coast and terrestrial environment.

ADP-glucose pyrophosphorylase (AGP) from barley (Hordeum vulgare L.) seed endosperm showed a lag in activity when assayed after storage at -20 °C. The cold-stored enzyme could regain most, or all, of its activity during 40-60 min following exposure to ambient tempera­tures. The lags were not observed when 2 mM MgCl 2 was added to the storage buffer before freezing. Storage at -20 °C, in the absence of MgCl 2 , led to the appearance of a low activity A GP form which was activated up to 3-fold by 3-phosphoglycerate (PGA) and had high K m values with ATP of 0.3 and 1.2 mM (with and without PGA, respectively). In contrast, storage at -20 °C in the presence of MgCl 2 or incubation at +20 °C resulted in an active enzyme which was only weakly activated by PGA (up to 30%) and had the respective Km values with ATP of 0.1 and 0.3 mM . It is suggested that low temperature may induce a change in the conformation and/or oligomerization state of the AGP protein, resulting in a low activity enzyme form which has distinct regulatory and kinetic properties.

Reconstitution experiments of light-harvesting complexes were performed with the green alga Chlorella fusca and the chlorophyll c-containing prasinophyte Mantoniella squamata using a modified method according to Plumley and Schmidt [Proc. N atl. Acad. Sei. U .S.A . 84, 146 -150 (1987)]. Changing the pigment supply quantitatively or qualitatively in the reconsti­tution mixture homologous and heterologous reconstitutes were obtained. In contrast to higher plants, light-harvesting polypeptides from green algae are able to bind the chlorophylls as well as the xanthophylls in different stoichiometries. Heterologous reconstitutes of M . squamata polypeptides give further evidence for a rather high flexibility of pigment recog­nition and binding. This is the first report of successful reconstitution of a chlorophyll c-binding protein. Contrary to chlorophyll c-less light-harvesting complexes, the reconstitution of M . squamata is strongly pH-controlled. In summary, the results give evidence for a high specificity of porphyrin ring recognition and variability in xanthophyll binding capacity. Therefore, it is suggested that at least in algal light-harvesting proteins chlorophyll organiza­tion may be determined by other mechanisms than xanthophyll binding.

The Q B binding site of photosystem II in green plants displays stereoselectivity for the (S′) stereoisomer of the α-methylbenzyl derivative of atrazine but not for derivatives with smaller substituents such as sec-butyl. We have shown that interactive models reflect the experimental data by determining the intermolecular energies between the D1 protein binding region (resi­dues Leu 210 to Val 280) and the triazine analogs. The intermolecular energy was calculated by van der Waals and electrostatic interactions after energy minimization of the combined structures to reduce inter and intramolecular strain. On the basis of these assumptions the role of stereoselectivity for optically active triazines was site responsible such stereoselectivity was identified.

The enzymatic mechanisms and energetics of nitrogenase-catalyzed photoproduction of hydrogen from organic C-compounds by purple bacteria are discussed in respect to the question of which of the following three enzymes or enzyme systems are rate limiting for H 2 -production: (a) the nitrogenase-complex; (b) the enzymes and electron transport proteins involved in hydrogen transfer from the organic substrate(s) to nitrogenase; and (c) the system of photosynthetic ATP-regeneration. Calculations of maximum in vivo rates of photosynthetic ATPregeneration (gATP-values derived from growth rates), and of ATP-consumption by nitrogenase- catalyzed H 2 -production, and comparison of these rates with the specific activities of the enzymes of hydrogen or electron transfer from the C-substrate to the nitrogenase-complex, make it very likely that, in Rhodospirillum rubrum, nitrogenase-catalyzed H 2 -formation is limited by the availability of ATP and, possibly, of reducing power. In two other nonsulfur purple bacterial species (Rhodobacter capsulatus and Rhodobacter sphaeroides), H 2 -photoproduction is probably not energy-limited.

The long-wavelength positive CD bands of poly[d(A) · d(T)] and poly[d(A-T) · d(A-T)] become inverted upon the addition of Hg(ClO 4 ) 2 . Poly[d(A) · d(T)] requires higher levels of mercury to undergo inversion than poly[d(A-T) · d(A-T)]. Mercurated poly[d(A) d(T)] is digested more rapidly than the control by DNase I or staphylococcal nuclease at low levels of Hg(ClO 4 ) 2 . Let r = [Hg(ClO 4 ) 2 ]added/[DNA-P]. A 4- to 5-fold rate increase occurs with DNase I at r = 0.25; a 2-fold increase with staphylococcal nuclease at r = 0.2. By contrast, digestion of poly[d(A-T )· d(A-T)] decreases immediately with increasing r. The noted rate increases appear to be due to a modification of poly[d(A)-d(T)] helix structure prior to the chiroptical conversion. The modification is interpreted as a widening of the minor groove, permitting, thus, a better binding of DNase I to its substrate. The overall changes in CD as well as enzymatic digestion rates are taken to signal mercury-induced alterations in helix screwness from rightto- left. They are totally reversible subsequent to the removal of mercury.

Azadirachtin A in ppm quantity inhibits proliferation and monolayer formation of Spodoptera frugiperda (Sf 9) insect cells in monolayer culture. The incubated cells demonstrate reduced rates of protein synthesis which finally leads to cell death. This growth inhibiting activity is compared with other botanicals such as ohchinin, salannin and volkensin. The high and specific activity of azadirachtin A on insect cells is discussed in comparison with its effect on a mammalian cell line, based on 2D PAGE analysis of the total protein contents.

Three spin-labelled fatty acids were used to detect the dynamics of lipid bilayer of apomem branes and purple membranes. It was found that ESR spectra of spin labels bound to apo­ membranes showed a temperature-induced changes rather similar to those seen with purple membranes. At the same time, however, the values of hyperfine splitting parameter 2Tm were lower as compared to purple membranes. The results pointed out that the removal of the retinal from purple membranes affects the dynamics of lipid bilayer and apomembranes were more rigid structure than those of purple membranes.

Cytochrome b, DNA Sequence, Polymerase Chain Reaction (PCR), Molecular Evolution, Procellariidae The cytochrome b gene of three European taxa of the family of Procellariidae was amplified from total DNA and sequenced. The sequence comparison shows that the Fulmar (Fulmarus glacialis) is significantly distinct from shearwaters, whereas Cory’s (Calonectris diomedea) and Manx Shearwater (Puffinus puffinus) are closely related. Although the populations of C. dio­medea can be distinguished morphologically, the sequences of cyt b differ only slightly between the Atlantic and Mediterranean subspecies (i.e. C. d. borealis versus C. d. diomedea) and do not reveal other population differences within subspecies.

Duftstoffe aus den abdominalen Haarbüscheln des männlichen Totenkopfschwarmers Acherontia atropos L. (Lepidoptera: Sphingidae) Pherom ones 92 [1], Odorous Substances from the Abdom inal Hair Brushes of the Male Sphingid Moth Acherontia atropos L. (L epidoptera: Sphingidae) Hans Jürgen Bestm ann, Joachim Erler, Otto Vostrowsky From abdominal hair brushes of male hawk moths Acherontia atropos (Lepidoptera: Sphingidae) 24 volatiles have been detected and identified by GC-MS analysis, caryophyllene (17), humulene (18), linalool (6), linalyl propionate (12) and geranic acid methylester (9) comprising the main constituents. Analyzing the terpenoid composition of volatiles from insects reared on different host plants as well as that of the essential oils from these plants it could be demon­ strated, that most components of the odour blend are not derived from the food plants but can be de novo synthesized by the insects.

By means of gas chromatographic, mass spectroscopic methods and combined GCelectroantennogram techniques (Z)-11-tetradecenyl acetate and (Z)-11-tetradecenyl acetate were identified as the two biological active components of the sex pheromone of the female cosmopterigid moth Limnaecia phragmitella. The mixture of 95% (Z)-11-tetradecenyl acetate and 5% of the (Z)-isomer were analyzed in the gland of females and confirmed as the most attractive synthetic blend for males in field bioassays.

Shot noise analysis is a frequently applied method for reconstructing elementary events from experimental data of noisy signals. The subject of this paper is the reconstruction of single photon responses in photoreceptors, the so-called quantum bumps, from experimental data which have been obtained at high light intensities where the quantum bumps can no longer be observed as individual events. The application of this method requires some basic prerequisites which are very likely not satisfied in photoreceptor cells. This situation makes the results of the method questionable. In order to estimate the reliability of shot noise reconstruc­tion in photoreceptors we directly compare the reconstruction results with well known input parameters by using a simulation model for the elementary mechanisms in the cell membrane which cause the response to light stimulation. The comparison shows that the reconstruction method starts to yield errors already at low intensities if only a few percent of the light con­ trolled ionic channels in the cell membrane are open on average. The errors of the method become about 100 percent in the light intensity regime between 10 percent open channels and the onset of bump speck contact on the membrane. The anticipation that the reconstruction method yields single channel events at high light intensities is disproved at least for physiologi­cally realistic intensities.

From Anacolia webbii the following five biflavonoids could be isolated: 2,3-dihydrophilonotisflavone, philonotisflavone, dicranolomin, 5′,3‴-dihydroxyamentoflavone and 5′,3‴-dihydroxyrobustaflavone. The compounds were identified spectroscopically.

From the moss Bartramia halleriana six biflavonoids have been isolated. Their structure was elucidated by chromatographic and spectroscopic methods. The compounds are bartramiaflavone, anhydrobartramiaflavone, philonotisflavone, 2,3-dihydrophilonotisflavone, 5′,3‴-dihydroxyamentoflavone and 5′,3‴dihydroxyrobustaflavone.

Ten methylated flavonols have been identified in the lipophilic resinous exudate found on aerial parts of Grin­ delia tarapacana, a gum weed species of Chile.