Volume 28, Issue 9-10

Mimulaxanthin, a xanthophyll from the petals of Mimulus guttatus (Monkey flower), has the structure of a 6,7,6′,7′-tetradehydro-5,6,5′,6′-tetrahydro,β,β-carotene-3,5,3′,5′-tetrol. This was con­ firmed by mass, nuclear magnetic resonance (NMR) and infrared (IR) spectra. The pigment yielded a diacetate, diacetate-di (trimethylsilyl)-ether, and a diether with acidified methanol. The free or acetylated pigment was transformed into the diacetylenic xanthophyll alloxanthin (7,8,7′,8′-tetra-dehydro-β,β-carotene-3,3′-diol) or alloxanthin-diacetate with acidic acetone.

Ripe fruits of wild growing varieties of strawberries had been homogenized under inhibition of the enzymes and extracted with the adding of an internal standard. About 40 main components could be identified and quantitatively determined by gaschromatographical-mass-spectrometrical investigations. Methyl ketones and secondary alcohols dominate in Fragaria moschata and Fragaria vesca, whereas especially ethylesters of the carboxylic acids C 6 to C 12 are formed by Fragaria chiloensis. Fragaria virginiana contains numerous components amongst which are especially the methyl-and ethylesters of the carboxylic acids C 6 to C 12 ; besides it contains, as distinctive marks, n-butyl-, n-hexyl, ra-octyl, and n-decylesters of the carboxylic acids C 4 to C 10 . All varieties exhibit a sorttypical distribution pattern of the aroma components.

The hydrogen-bonded complexes of 17 α-ethinyl-estradiol, progesterone, and testosterone with adenine- and uracil-derivatives have been investigated by means of nuclear magnetic resonance (NMR) spectroscopy using deutero-chloroform as a solvent. The thermodynamic and NMR-parameters (equilibrium constant K, enthalpy ΔH, entropy ΔS, and relative chemical shift of the complexes Δδ C ) for selfassociation and mixed association have been determined. The strongest complex was formed by the phenolic hydroxyl group of estradiol with dimethyl-adenine (K = 14 mole- 1 , - ΔH = i kcal/mole, - ΔS = 8 cal/m ole-grad). The values were considerably less for the OH-17 group of estradiol and testosterone. The interaction of the keto groups of progesterone and testo sterone with nucleobases was very weak: K < 1 .0 mole - 1 . The biological importance of these results is discussed.

The mass spectrometric fragmentation behavior of glycosyl glycerides is discussed with special regard to the localisation of the fatty acids present in the molecule and to the applicability for mixture analyses.

With highly purified preparations of ferredoxin-NADP reductase (EC 1.6.99.4; also EC 1.6.1.1) from spinach chloroplasts a strong flavin fluorescence was observed (excitation at 450 nm). At pH 7.0, the fluorescence was approximately 40% higher than that of free FAD. Pure reductase from the heterokont alga Bumilleriopsis had only a fluorescence of less than 5% of that of the spinach protein. Essentially the same low fluorescence was found with impure spinach reductase preparations. The low-fluorescent samples of both species exhibited about the same quenching response to salts and buffers which differed from the highly fluorescent spinach flavoprotein preparation. The low fluorescence of the algal protein could be enhanced by NADP, but not by ferredoxin. Maximum fluorescence increase was observed when reductase and NADP were present in a 1:1 molar ratio. Ferredoxin did not counteract the reductase are hereby substantiated.

Bilirubin shows a red-shift in the visual spectra on binding to albumin. In bilirubin-cationic detergent systems a similar spectral change was observed. These comparisons allow one to deduce that the environment of the binding site in albumin is most likely apolar than when bilirubin is solubilized by the cationic detergents.

The reaction of malonic acid and bromate in the presence of catalytic amounts of cerious ion under oscillating conditions in sulphuric acid was investigated. After two hours reaction time 26 mM bromate were consumed and 42 mM CO 2 produced. No formic acid was detected. Furthermore, 14 C-tracer experiments suggest that malonic acid is first brominated and subsequently decarboxylated.

From the differences in electronic structure of 5-halogenated uracil derivatives and thymine there is discussed the connection with different radiosensibilization. At the same time the calculated energy change of the second and third excited singlet states for the particularly sensibilizating substances 5-bromo-uracil and 5-iodo-uracil compared with the remaining uracil derivatives is remarkable. In connection with different charge distribution this difference in principle may cause different energy transport processes. The very phenomenon is to be mentioned which has been discussed in previous papers dealing with the different carcinogenic molecules 3,4-benzpyrene and 1,2-benzpyrene.

Radical formation by irradiation with X-rays in single crystals of 1-methyluracil has been measured using ESR-spectroscopy at 9.5 GHz and 35 GHz. When irradiating and measuring at 77 °K radicals characterized by hydrogen abstraction from the methyl group were found to be predominating. For the hyperfine splittings principal values of 8.5 G, 18.2 G, 30.5 G were found for both α-protons and 3.3 G, 2.4 G, 1.7 G for the N (1)-splitting. Pairs of abstraction radicals were also found under these conditions showing quintet splittings of about 10 G and anisotropic dipolar coupling. Average distances parallel to c of 6.3 Å and 6.5 Å were found for two types of pairs while those perpendicular to c were not analyzed in detail. Irradiating and measuring at room temperature an additional sextet pattern was found in the spectrum and attributed to a radical formed by addition of hydrogen at C (5). For the hyperfine splittings principal values of 8.1 G, 17.5 G, 30.0 G were found for the α-proton and 31.2 G, 34.4 G, 34.1 G for the two equivalent β-protons. Radical concentrations were determined at 77 °K yielding about 90% abstraction radical, 15% of these in pairs and 10% of addition radical. About half of the abstraction radicals are converted to addition radicals between 200 °K and 280 °K. The latter disappear at about 460 °K leaving a fraction of abstraction radicals which is annealed at even higher temperatures.

Isopiestic vapor pressure measurements and calorimetric determination of the heat of dilution have been performed and evaluated with respect to enthalpy, entropy and free enthalpy in the ternary solutions water+ glycin+ urea and water+ alanin + urea. The free enthalpy of transfer for the process: Amino acid from water to water+ urea, which can be derived from these measurements, does not agree with the value calculated from solubility measurements. The reason for this discrepancy and the values of entropy and enthalpy in terms of hydrophobic interaction are discussed. Supplementary measurements of the proton magnetic resonance in these solutions are included.

β-Indole acetic acid (IAA) (10 -7 - 10 -5 M ) enhanced elongation of Avena coleoptiles is shown to be correlated with increased K + net influx and H + net efflux. The data suggest a 1:1 exchange of K + and H + . It is suggested that an IAA controlled K + -H + -exchange pump is involved in IAA regula­tion of elongation.

The time-courses of the level of glutathione reductase (GR; EC 1.6.4.2) were followed in cotyledons and hypocotyl of the developing mustard seedling in the dark and under the influence of light (phytochrome). Localization of GR on polyacrylamide disc electrophoresis columns indicate that 2 isoenzym es of GR are present in both organs under all experimental conditions. GR can be induced by light (phytochrome) in the cotyledons; however, there is no influence of light (phytochrome) on the time-course of the level of GR in the hypocotyl. While the actual lag-phase of the response in the cotyledons is less than 6 hours (onset of light at 48 hours) there is no detectable effect of light on apparent GR synthesis before approx. 42 hours after sowing. Irrespective of the onset of light (at 24 or 36 hours after sowing) the time-course of the enzyme level remains precisely the same. A red pulse given at 24 hours after sowing leads to an increase of the enzyme level as determined 60 hours later. T he effect of the red pulse is fully reversed by a far-red light pulse given at 24 hours but not 12 hours later. Facts of this kind have led to the concept of a stable inter­ mediate in the chain of regulatory events between phytochrome (P fr) and GR increase. No in d i­ cations of a coordinated, simultaneous induction by phytochrom e of GR and ascorbate oxidase (AO) could be found. This result does not support the concept that a respiratory chain exists in which AO functions as a terminal oxidase.

Analyses of DNA from tumorous and non tumorous cultures of Crepis capillaris by analytical equilibrium centrifugation in a neutral CsCl gradient revealed significant differences in regard to the content of a heavy component satellite, which was more highly represented in tumorous cultures. DNA of plant leaves showed a unimodal distribution of molecules. The choice of suitable controls served to demonstrate that the component satellite was not exclusive of tumorous tissues. The higher satellite content of tumorous cultures is probable related to their higher growth rate.

1. The house fly shows landing reaction to an expanding visual stimulus or to a decrement of the environmental light level. The quantitative relationship between the dependence of landing reaction on expansion and on light level decrement is analyzed. 2. The different properties of the reactions at different light levels may be correlated with the two visual systems in Diptera and may be explained by the existence of an alterting mechanism that weighs stimuli for landing reaction at low illumination levels. 3. The landing reaction resembles the optomotor reaction with respect to the influence of the contrast of the stimulating pattern. The landing reaction appears to be invariant to the phase relations between the spatial components of the periodic patterns used in the present experiments. Introduction

1. The behaviours of monocular and binocular flies are compared with respect to the landing reaction. It is found that landing reaction is elicited through different mechanisms by stimulating the zones of single or of double vision: Monocular stimulation in the field of single vision evokes reactions with both ipsilateral and contralateral leg s; monocular stimulation in the field of double vision evokes reaction only with the ipsilateral legs. 2. T he relationships between landing and optomotor reactions are analyzed. It is found that, a. W hen the fly is not free to turn itself, it may react to a lateral displacement in the visual field (optomotor stimulus) with a landing reaction ; b. The threshold for landing evoked by an expansion in the visual field (landing stimulus) is much low er than the threshold for landing evoked by a lateral displacement; c. A horizontal lateral displacement in the visual field of an eye is adequate to evoke the landing reaction only if it is perceived in the direction from the front to the back of the eye; d. W hen the fly is free to turn itself, it can present both landing and opto­motor reactions to a optomotor stimulus; e. W hen the fly is fixed at a point, landing reaction can be evoked also by an escape stimulus.

Action potentials of some of the 3578 nerve fibres in the cervical connective of Drosophila melanogaster can be recorded with extracellular electrodes. The spike rate increases if moving striped patterns are presented to the compound eyes, especially with horizontal front-to-back movement. The response is small or absent with the reverse (or with vertical) directions of movement. The main properties of this response are described, and briefly discussed.

Receptor potentials are measured extracellularly by means of an air gap method along the optic nerve of the median and the lateral photoreceptor of the barnacle. Both photoreceptors have an outward dark current (photoreceptor positive with respect to the nerve) which is diminished ap­proximately 70% during the plateau phase of the receptor potential. Ouabain abolishes dark current and receptor potential in the same proportion. With a Limulus lateral eye preparation a dark cur­rent and light induced current changes were measured which had the same polarity and a similar magnitude as the receptor currents of the barnacle.

The kinetics of rhodopsin photolysis in sonicated suspensions of rod outer segments (ROS), unsonicated ROS suspensions and rhodopsin detergent solutions were compared. No significant kinetic differences were detected ; however, the energy of activation for the metarhodopsin I to metarhodopsin II reaction was somewhat higher in sonicated ROS suspensions than in the unsonicated suspensions. While the sonicated preparations contained glycerol, it was not possible to show a chemical influence of glycerol on the reactions of the rhodopsin decay. An often assumed effect that the ROS outer membrane acts as a barrier toward diffusion of protons could not be confirmed.

Established lines of both fibroblastoid and epithelioid cells have been investigated by electro-physiological and freeze-fracture methods. Between the ionically coupled (by "low-resistance junctions") fibroblastoid cells numerous gap junctions were found. Between the non-coupled epithelioid cells gap junctions could not be detected.

Amoeba proteus was ultrasonically irradiated, the ultrasonic mean output intensity being about 0.4 W/cm 2 at 1 MHz. Contractions of amoebae, rotations and aggregation of intracellular particles and cell membrane damages were observed. At even lower ultrasonic intensities sodium pinocytosis was found to increase after application of ultrasound.

A procedure is described for obtaining DNA-dependent RNA polymerase form B from calf thymus in high purity. The procedure includes homogenization in low salt, sedimentation of chromatin at 50 000 x g, adsorption to DEAE-cellulose in a batch procedure, DNA-agarose chromato­graphy, and chromatography on DEAE-Sephadex. Analyses of the preparation by band sedimentation and gel-electrophoresis indicate a high purity of the enzyme.

The mutant strain Aerobacter aerogenes 62-1 AC, pab - , accumulates a labile substance, desig­nated Compound A which supports the growth of other pab - mutants. Previous studies seemed to indicate that Compound A might be an intermediate in the conversion of chorismate to 4-amino-benzoate (Altendorf, Bacher, and Lingens, Z. Naturforsch. 24 b, 1602 [1969]). The present experi­ ments show that Compound A is 4 -(D-glucosylamino)-benzoic acid. This substance which is clearly not an intermediate in the biosynthesis of 4-aminobenzoate is formed by reaction of 4-aminobenzoate produced de novo by the mutant with exogenous glucose. Mutant 62-1 AC has the unimpaired capacity to synthesize 4-aminobenzoate as shown by direct enzyme studies. Mutant 62-1 AC re­ quires approximately 200 times more 4jaminobenzoate for growth than other pab" mutants of A. aerogenes with defective 4-aminobenzoate synthetase. The genetic defect of mutant 62-1 AC seems to be located in a metabolic system concerned with the utilization of 4-aminobenzoate rather than its synthesis.

RNA, tobacco mosaic virus, potato X virus, gel-electrophoresis, infectivity A simple device is standardised for the elution of biologically active ribonucleic acid from polyacrylamide gel after electrophoresis. The pieces of gel containing the nucleic acid to be re­ covered are held in position by two short cylinders of foam rubber in a glass tube and the nucleic acid is concentrated over a sucrose-containing buffer layer by electrophoresis in a standard electro­ phoretic equipment. Using this method nucleic acids can be recovered undamaged almost quanti­ tatively, as shown for microgram quantities of two viral RNAs by infectivity assay. The results offer additional experimental support to the single-component character of tobacco mosaic and potato X viruses.

Pristomyrmex pungens Mayr, Pheidole nodus Smith, Lasius (Dendrolasius) spathepus Wheeler, Crematogaster laboriosa Smith, monoterpene hydrocarbons (α-pinene, β-pinene, camphene, limonene)