0000000000072858
AUTHOR
Elmar Hartmann
Effect of Light on the Composition of Mitochondrial Lipids from Hypocotyl Hooks of Bean Seedlings (Phaseolus vulgaris L.).
Summary Mitochondria were isolated and roughly purified from bean seedlings (phaseolus vulgaris) treated with different red light (660 nm) irradiation programmes. Etiolated seedlings were irradiated for short terms or grown in red light. The mitochondria from differently treated seedlings were analysed for their phospholipid and fatty acid patterns. The mitochondrial phospholipid patterns from green and etiolated seedlings were rather similar. This was also valid for the fatty acids from the phospholipid fraction whereas the fatty acid patterns of the glycolipids showed differences. Remarkable changes were observed in the phospholipid pattern of the mitochondrial fraction after short-term i…
Influence of Light on the Bioelectric Potential of the Bean (Phaseolus vulgaris) Hypocotyl Hook
By use of surface electrodes electropotenlial measurements were carried out on hypocotyl hooks of Phaseolus vulgaris seedlings. The hooks were illuminated with a small spot of white, blue, red or far red light. The potential changes in bean hypocotyl hooks do not show the red-far red reversible characteristics of phytochrome-mediated processes. By experimenting with inhibitors of photosynthesis we could demonstrate that the light-triggered potential changes in green bean hooks are correlated to photosynthetic electron transport phenomena. The red-light-induced transient is a depolarization, whereas blue light induces a hyperpolarization. Etiolated beans exhibit no bioelectric potential chan…
Partial purification and initial characterization of phytochrome from the mossAtrichum undulatum P. Beauv. grown in the light.
The extraction and partial purification of phytochrome from light-grownAtrichum undulatum P. Beauv., a chlorophyllous moss, is described. Polyethyleneimine and salt fractionation followed by hydroxyapatite and Affi-gel-blue chromatography were used to separate phytochrome from chlorophyll, and to purify the pigment. All steps were performed in the presence of Triton X-100 which improved the yield by a factor of about three. The protein has a molecular weight some-what larger than that ofAvena phytochrome (124 kDa), as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis. It cross-reacts with a monoclonal antibody against phytochrome from etiolated …
Über den Ureidstoffwechsel beim Laubmoosprotonema von Funaria hydrometrica L. (Sibth.)1)1)Herrn Prof. Dr. Dr. Kurt Mothes zum 75. Geburtstag gewidmet.
Summary The activity of allantoinase (EC 3.5.2.5) is influenced by light and darkness. The extracts of dark-grown moss protonema showed a very higher enzyme activity than the extracts of light-grown plants. The allantoinase activity was increased by light-dark and decreased by dark-light transitions. DMAP mimicked light effects by stabelizing the charakteristic light depending enzyme avctivities in the dark. The inhibitors DCMU, DNP and CCCP increased the enzyme activity of light-grown moss protonema, to some extend they induced a “physiological dark condition”.
Über die wirkung des phytochroms beim laubmooskallus II. Sauerstoffmetabolismus und acetylcholinwirkung
Summary The oxygen metabolism is a good parameter for the determination of rapid responses of green moss callus to light. We measured the oxygen uptake with the Warburg method and polarographically with a Clark electrode and the YSI-oxygen monitor. The exposure of dark grown moss callus to red light (5–20 min) induced a rapid increase in O2-uptake after switching off the light. The respiration change depends on the exposure duration and the light intensity. During the first 2 or 3 h after irradiation with red light and with red-far red light, the rates of the O2-uptake show no differences but after this lag-phase the 2 curves are splitting. The respiration of the red irradiated cells remain…
Isolierung und charakterisierung einer cholinkinase aus Phaseolus vulgaris L.-Keimlingen
Summary The enzyme choline kinase (ATP: Choline phosphotransferase E.C. 2.7.1.32) was extracted and partially purified from hypocotyl hooks of Phaseolus vulgaris L. seedlings. K m -value and pH-dependence of the activity were determined. The amount of enzyme activity in extracts depended on light conditions used for plant growth. Etiolated seedlings showed much lower enzyme levels than those grown in white light. Blue and red light conditions decreased enzyme levels below dark values. The in vitro enzyme activity was influenced by inhibitors and growth regulators. The enzyme activity was stimulated by Atropine, 2-Chloroethylammoniumchloride (Cycocel) and Gibberellic acid and was inhibited b…
Moss cell cultures as sources of arachidonic and eicosapentaenoic acids
AbstractLipid classes from tissue cultures of the moss Leptobryum pyriforme (Hedw.) Wils. were analyzed. In the total lipid fraction, this species contained 20% arachidonic acid and about 7% eicosapentaenoic acid. The distribution of these fatty acids showed a preference for the phospholipid fraction. In particular, the phosphatidylethanolamine fraction was enriched in arachidonic acid. The arachidonic acid content of Leptobryum could be altered by transferring the cultures to different culture conditions. Mosses show high organic mass production in tissue cultures in relatively simple media. The great potential of using mosses as sources for the production of polyunsaturated fatty acids is…
Biochemical Characterization of an Acetylcholine-hydrolyzing Enzyme from Bean Seedlings.
An acetylcholine hydrolyzing enzyme was prepared and purified (40 times) from dwarf bean hypocotyl hooks. The purity of the enzyme was proved by polyacrylamide gel electrophoresis. The molecular weight of the enzyme was determined to be 65,000 daltons. Enzyme activity was the highest at pH 8.0 and between 30 and 36 C. The enzyme had an apparent affinity constant (K(m)) for acetylcholine of 460/micromolar. The affinity for substrate analogs increased from butyrylthiocholine to propionylthiocholine to acetylthiocholine. The enzyme activity was inhibited by choline, neostigmine, physostigmine, manganese, and calcium. Magnesium had no influence on the enzyme activity. We conclude that the enzym…
Üher den Ureidstoffwechsel heim Lauhmoosprotonema von Funaria hygrometrica L. (SIBTH.)
Summary The uptake of allantoine-7- 14 C by moss protonema grown in submerged culture is controlled by light and by the degree of catabolisation within the cell. The rate of uptake was enhanced by the application of ATP + glucose to the medium of a dark grown culture. The degradation products of allantoine-7- 14 C in light grown protonema are allantoic acid and urea. Urea is degraded in the Henseleit-Krebs-cycle to ornithine, citrulline and arginine. Urea is a further source of radioactive CO 2 . In darkness, the single product of allantoine degradation is allantoic acid. Allantoicase is blocked in the dark but the metabolism can be activated by the application of ATP or ATP + glucose to th…
Fatty acid composition of mutants of the moss Physcomitrella patens
Abstract The fatty acid composition of various mutant strains of the moss Physcomitrella patens has been compared to the wild-type. These included strains defective in their responses to auxins and/or cytokinins, one which releases much more cytokinin into the medium than the wild-type, and two aphototropic strains. The lipids of the aphototropic mutants were also studied after culture in different light regimes. Although some differences in fatty acid composition have been found between strains, these alone are probably not responsible for their physiological differences. Considerable changes occur in many fatty acids in senescent or dark-grown material, including changes in the proportion…
Über den Ureidstoffwechsel beim Laubmoosprotonema von Funaria hygrometrica L. (Sibth.)
Summary 1. Allantoin and allantoic acid were about 6 % of the total nitrogen content of moss protonema (Funaria hygrornetica L.). 2. The level of endogenous allantoin depends on the spectrum colour of the irradiation. The peaks coincide with the peaks of a chlorophyll absorption spectrum from a methanolic extract of moss protonema. 3. The total amount of allan to in consists of two parts. One part is supplied by metabolism in darkness but the main one depends on light. Green- and far red light are “physiological dark conditions” for the moss protonema. In the dark ureide degradation comes to an end with allantoic acid. There are only traces of urea. 4. The coinciding correlations between th…
The Influence of Acetylcholine and Choline on the Incorporation of Phosphate into Phospholipids of Etiolated Bean Hypocotyl Hooks
Summary Acetylcholine influenced the radiolabelling of phospholipids in vivo in etiolated hypocotyl tissue of dwarf beans in darkness. Under aerobic conditions the specific activity of the phospholipids was decreased and under anaerobic conditions increased. The biosynthesis of phospholipids was strongly increased by the bivalent cations calcium and manganese and decreased by 2,4-dinitrophenol, anaerobiosis, atropine and ascorbic acid. Magnesium stimulated the uptake of the radioactive phosphate but not the specific activity of the phospholipids. The results are discussed in comparison with the «phospholipid-effect» of acetylcholine in animal tissues.
�ber den Nachweis eines Neurohormones beim Laubmooscallus und seine Beeinflussung durch das Phytochrom
The presence of a neurohormone in moss callus could be demonstrated by means of pharmacological experiments on the heart of the frog (Rana temporaria L.) and by chromatography.The hearts react in the same manner as they do to application of acetylcholine and the substance resembles acetylcholine in its Rf-value. Therefore it is suggested that this hormone is identical with acetylcholine. The concentration of the hormone in the callus cells is mediated by the phytochrome. Moss callus cultivated under red and far-red illumination contain less substance than moss callus grown in red light.
Modulation of Fatty Acid Patterns During Protoplast Isolation
Protoplast isolation and regeneration is known from numerous plant species (Binding et al. 1). But there are plant species which show very unconstant regeneration or no reaction at all, even if the isolation showed high viability of the protoplasts. Does this lacking response only depend on medium composition and effectors or are there other unknown conditions? The procedure of protoplast isolation and the use of strong hypertonic media is a dramatic disturbance of cell metabolism and might be a stress situation, which cannot be overcome by the cell. Fleck et al. (2) reported “osmotic-stress proteins” in Nicotiana sylvestris protoplasts and Kaiser et al. (3) showed a remarkable influence of…
Distribution and chemotaxonomic significance of acetylenic fatty acids in mosses of the dicranales
Abstract Thirty-eight moss species from four families of the order Dicranales were analysed for the fatty acid composition of their acyl lipids. In the Ditrichaceae and the Dicranaceae numerous species were found to contain acetylenic fatty acids in their triglycerides, 9,12,15-Octadecatrien-6-ynoic acid was the major component, often accounting for more than 80 mol%, whereas 9,12-octadecadien-6-ynoic acid was found in small amounts of less than 5 mol%. In some genera, all the species examined contained acetylenic fatty acids, e.g. Dicranella and Dicranum , whereas in the genus Campylopus all five species tested were free of acetylenic compounds. Two genera, Ditrichum and Dicranoweisia , we…
Phosphatidylinositol specific phospholipase C of plant stems : membrane associated activity concentrated in plasma membranes.
A phosphatidylinositol-specific phospholipase C of plant stems (EC 3.1.4.10) assayed at pH 6.6 and at 30 degrees C cleaved phosphatidylinositol such that more than 85% of the product was inositol-1-phosphate. Other phospholipids were cleaved 5 to 10% or less under these conditions. The phospholipase had both a soluble and a membrane-associated form. The soluble activity accounted for approximately 85 to 90% of the activity and 15% was associated with membranes. The membrane-associated activity was most concentrated in the plasma membranes of hypocotyl segments of both soybean (Glycine max) and bushbean (Phaseolus vulgaris). The plasma membrane location was verified by analysis of highly pur…
Uptake of Acetylcholine by Bean Hypocotyl Hooks
Summary The uptake of acetylcholine by etiolated hypocotyl hooks of beans ( Phaseolus vulgaris L.) is influenced by light and the pH-value of the incubation medium. Acetylcholine is hydrolysed up to 90 % during the uptake. The hydrolysis is inhibited by pH-value lower than 6.0 and by eserine, an inhibitor of the acetylcholinesterase. The high amount of hydrolysis is a serious problem in experiments involving acetylcholine and necessitates the inclusions of adequate controls without which direct effects of acetylcholine cannot be distinguished from reactions of its metabolic products.
Über den Allantoinstoffwechsel des Laubmooskallus und seine Beeinflussung durch Licht
Summary 1. The amount of allantoin and allantoate was determined in moss callus grown under various light conditions. It can reach 26,5 % of the plant nitrogen content. The accumulation is influenced by light intensity and colour. 2. Red-light (660 nm) causes a greater allantoin level in the cells than blue light and white light illumination. Red-light favours the formation of young setae from the moss callus. We could detect a relation between the intensity of seta-development and the amount of allantoin. The accumulation is increasing with the growth of the setae. 3. Blue-light (440 nm) enhances the chlorophyll synthesis and promotes chloroplast develop ment. This effect is correlated wit…