Influence of phosphorus supply and light intensity on mycorrhizal response inPisum-Rhizobium-Glomus symbiosis

The influence of mycorrhizal colonization withGlomus mosseae on parameters of N₂ fixation and plant growth was studied in pot experiments with pea plants (Pisum sativum L.) infected withRhizobium leguminosarum and supplied with varied levels of phosphorus (P) and nitrogen (N). Reduced light intensities were used to evaluate the dependence of the microsymbionts on assimilate supply. In plants grown with low P supply, mycorrhization increased the concentration of P in shoots, and thus N₂ fixation. Reduced light intensity significantly depressed mycorrhizal colonization and nodule growth in low-P plants. When P supply did not limit plant growth and N₂ fixation, however, the percentage of mycorrhizal colonization was reduced due to the higher P status, and the microsymbionts were not impaired by low light intensities. To maximize carbohydrate supply, another experiment was carried out at high light intensity of 900 mol m^–2s^–1 and with non-limiting P supply. Nitrogen fertilization, given as starter N, enhanced plant growth, but delayed nodule formation. Towards flowering, nodulation rapidly increased, but less so inGlomus inoculated plants. After 28 days mycorrhizal plants were lower in shoot dry weight, nodule dry weight and nitrogenase activity. The results suggest that under many, but not all, environmental conditions the host plant is able to restrict mycorrhizal colonization and, thus, to prevent impairment ofRhizobium symbiosis.deceased in May 1994     

Über den Phytoöstrogengehalt einiger Pflanzen

Summary The quantity of phyto-estrogens in red clover, hop, peas, and cabbage was estimated by titration on castrated female rats and infantile mice. The level of phytoestrogens was as follows: in hop 1050–2000/kg, in peas 4–6/kg, in cabbage 24/kg, and in red clover 6–9/kg. The author supposes that the sexual disorders described byRosenberger ¹⁴ in cows fed with cabbage, can be explained by the presence of phyto-estrogens in this plant.     

Insect hormones in vertebrates: Anabolic effects of 20-hydroxyecdysone in Japanese quail

Ecdysteroids are hormones controlling cell proliferation, growth and the developmental cycles of insects and other invertebrates¹. They are occasionally present in various unrelated plants for no apparent reason; no phytohormonal function has yet been identified. In certain cases, ecdysteroids are accumulated to high levels in leaves, roots or seeds. Some ecdysteroid-containing plants have been known as medicinal plants for centuries. One of them,Leuzea carthamoides Iljin (Asteraceae), growing in Central Asia, contains 0.4% ecdysteroid in dry roots and 2% in seeds. A pharmacological preparation from this plant, Ecdisten, is already available as a commercial preparation for its anabolic, tonic and other effects, for medical use (review²). It remained problematic, however, whether ecdysteroids were truly responsible for these effects, becauseLeuzea contains a number of other biologically active compounds in addition to ecdysteroids. We extracted and purified ecdysteroids from the seeds ofLeuzea. With 6 g of 96% 20-hydroxyecdysone (20E), we made a large-scale feeding assay with Japanese quail to find out whether ecdysteroid alone could duplicate the anabolic effects of the seeds. We found that the 96% ecdysteroid increased the mass of the developing quails in a dose-dependent manner, with the rate of increase proportional to the ecdysteroid content in the seeds; there was a 115% increase in living mass with 100 mg kg^–1 of pure 20E compared with 109.5% increase with 100–180 mg kg^–1 20E equivalents in the seeds. We conclude that the plethora of growth-promoting, vitamin-like effects induced in vertebrates byLeuzea is mediated by ecdysteroids.     

Variations de l'activité des auxines-oxydases dans les racines duLens

Summary 2, 4-dichlorophenol (DCP), 2, 4-dinitrophenol (DNP) and 2, 4-dinitro-o-cresol (DNC) applied at a concentration of 1.10^–7 to 1.10^–3 M, produce a dramatic increase in IAA-oxidase activity in young cells ofLens root. IAA destruction by breis from root tissues was inhibited by Mn⁺⁺ ion at low concentrations of DCP (1·10^– to 1.10^–7 M), but was enhanced by Mn⁺⁺ ion at higher (1.10^–5 to 1.10^–3 M) DCP levels.

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Ce travail a pu être entreprise grâce à l'appui duFonds national suisse pour la Recherche scientifique.     

Influence of cyclic nucleotides on protein synthesis in vascular smooth muscle

Summary The incorporation of leucice-¹⁴C into protein in bovine mesenteric arteries was augmented by cyclic GMP (10^–3 M) and decreased by cyclic AMP (10^–3 M). There was no effect of 5 AMP (10^–3 M). The phosphodiesterase inhibiting drugs theophylline (10^–3 M) and papaverine (5×10^–5 g/ml) both decreased the leucine-¹⁴C incorporation.We are indebted to Mrs.Lena Burlin for hear assistance. Finacial support has been provided by the Swedish State Medical Research Council (No. 04X-101X-4498).     

3′–5′-cAMP and lysosome membrane labilization

Zusammenfassung Es wird gezeigt, dass 3–5-cAMP (10^–3 M) und Theophyllin (10^–4 M) die Permeabilität derjenigen Lysosmen-Membranen steigern, die aus Rattenleberzellen in bezug auf saure Phosphatase and in bezug auf -Glucuronidase-Enzyme präpariert wurden.     

Further new diterpene esters from the irritant and cocarcinogenic seed oil and latex of the caper spurge (Euphorbia lathyris L.)

Zusammenfassung Ein Diacetat-Benzoat und ein Diacetat-Nicotinoat des neuen Diterpens «Lathyrol» sowie weitere Ester des Diterpens Ingenol wurden aus dem Samenöl bzw. dem Latex vonEuphorbia lathyris L. isoliert. Die chemische Struktur von Lathyrol wurde mittels spektraler Daten aufgeklärt. Lathyrol ist die Muttersubstanz der beiden bereits früher ausE. lathyris isolierten makrozyklischen Diterpene 6.20-Epoxy-lathyrol und 7-Hydroxy-lathyrol. Es wird ein Biogeneseweg für Diterpene aus Euphorbiaceen vorgeschlagen.

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Measurements and discussions of NMR spectra by Prof.M. Anteunis, Gent, and Dr.A. Mannschreck, Heidelberg, are gratefully acknowledged.     

Glutamate decarboxylase in barley aleurone and its relationship toα-amylase development during germination

Résumé L'enzyme glutamate décarboxylase se trouve dans les extraits d'eau de l'aleurone de l'orge. Au début de la germination, l'activité de cette enzyme augmente, mais après, quand apparait l'enzyme -amylase, elle diminue. Quoiqu'au dessous d'une concentration de 2×10^–6 M l'acide -amino butyrique (GABA) n'affecte pas l'activité de l'-amylase in vitro, la GABA à 5×10^–6 M peut provoquer une inhibition de 25% qui n'est pas modifiée par des concentrations de GABA comprises entre 5×10^–6 M et 10^–3 M.     

Inhibitory action ofγ-aminobutyric acid (GABA) onAscaris muscle

Zusammenfassung Die somatische Muskulatur vonAscaris lumbricoides wird durch-Aminobuttersäure in Konzentrationen von 10^–6-10^–5 M völlig gehemmt. Eine hnliche Hemmung wird durch Piperazin (10^–3 M) erzielt. Beide Substanzen steigern die Cl-Permeabilität der Muskelmembran.

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On leave of absence from the Instituto de Biofísica, Universidade do Brazil, Rio de Janeiro (Brazil).     

Influence of environmental conditions on the amount of N2O released from activated sludge in a domestic waste water treatment plant

Waste water purification is characterized by intensive mineralization and nitrification processes. Because of the high O₂ demand, temporarily anaerobic conditions may be produced, and denitrification by nitrifying organisms as well as heterotropic denitrification may contribute to N₂O release. In situ measurements (1993–1994) suggest that N₂O is released from activated sludge in a domestic waste water treatment plant at an average rate of 1040 g m^–2h^–1 with a range between zero and 6198 g m^–2h^–1. The production of N₂O seems to be related to the concentration of NO ₂ ^– and NO ₃ ^– as well as to the pH. In the waste water about 75–200 g N₂O l^–1 is dissolved. This N₂O is released after discharge into the receiving waters. The N₂O is produced essentially by nitrification rather than by heterotropic denitrification. On a long-term scale the increasing use of mechanical-biological waste water purification plants world-wide may add increasingly to the anthropogenic production of N₂O, although the present amount of N₂O produced is negligible compared to its global terrestrial production.     

Activité antifibrillante chez l'animal d'un nouveau dérivé de la phényl-éthylamine

Summary A new synthetic phenyl-ethyl-amine derivative, the 2-[N- (3, 4-methylen-dioxyphenylethyl)-methylaminomethyl]-tetrahydrofuran, No. 11 081, exhibits a strong protective effect against cardiac fibrillation and arrhythmias produced by various experimental methods: against fibrillation due to aconitine 3 × 10^–8 on the isolated cat's heart, it is active in a concentration of 10^–6–2 × 10^–6. Against cardiac arrhythmias produced in the cat by adrenaline + CHCl₃ or cyclopropane, it shows a protective effect by 5–10 mg/kg i.v. and even perorally by 50 mg/kg. In these tests, the antifibrillatory activity of the new compound seems to be roughly the same as that of -fagarine, and higher than that of procaine.

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9^e communication sur les dérivés des alcoylène-imines; 8^e communication, cf. Exper.10, 261 (1954).     

The action of iodoacetate on the antigenic power of insulin

Résumé Nous avons observé que le iodoacétate en concentrations de 1·10^–4, 5 · 10^–5 et 1 · 10^–5 M et préalablement incubé à 37 °C, a une influence de l'ordre de 61, 50 et 44% respectivement sur la totalité du pouvoir antigénique de l'insuline de buf. L'effet inhibitif est proportionnel à la durée d'incubation et l'on ne constate pas de différences lorsque les concentrations de l'hormone se trouvent entre 100 et 300U/ml.     

Untersuchungen über die β-adrenolytische Wirkung sowie den Einfluss auf Refraktärzeit und Kontraktilität von INPEA und MJ1999 am Meerschweinchenvorhof

Summary In isolated guinea-pig atria, the-adrenolytic isomerd(–)INPEA provoked a stronger prolongation of the refractory period (rp) than did the inactivel(+) isomer. The-adrenolytic drug MJ 1999 prolonged likewise the rp, although it caused no unspecific effect, i.e. an inhibition of contractile force. These observations lead to the conclusion that not only the unspecific local anaesthetic but also the specific-adrenolytic effect is of importance for the prolongation of rp.     

Adrenocorticotropic effect in humans of a syntheticβ 1–24 corticotrophine derivative

Zusammenfassung Am Menschen wurde die adrenocorticotrope Wirkung von ^1–24 Corticotrophin Tetracosactid undd-Serin¹-17, 18 Diornithin ^1–24 Corticotrophin nach i.m. Injektion untersucht. Das synthetische Derivat erwies sich als etwa fünfmal stärker wirksam als das natürliche Tetracosactid, hauptsächlich durch eine Verlängerung der Wirkungsdauer.

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The synthetic peptides were kindly supplied by CIBA Ltd. Basel, Switzerland.     

Strong mutagenic action of a bipyridylium herbicide in a N2-fixing blue-green alga

Summary The herbicide paraquat (1,1-dimethyl-4,4-bipyridylium ion) has been found to exert a growth inhibitory effect on the N₂-fixing blue-green algaNostoc muscorum in nitrogen-free (N₂) and NO ₃ ^– media, without any apparent inhibitory or stimulatory effect on the heterocyst-forming capacity of the organism. With a dose of paraquat permitting about 20 and 50% survival of this alga a reverse mutation (fromhet ⁺ nif ^– auxotrophy tohet ⁺ nif ⁺ prototrophy), a forward mutation (for L-methionine-DL-sulfoximine [MSO]-resistance), and an auxotrophic mutation (for carbon-auxotrophy through methylamine [MA]-resistance) have been obtained. The toxic and mutagenic effects of this agrochemical have been compared with those of the well known mutagen MNNG (N-methyl-N-nitro-N-nitrosoguanidine) and found to be stronger than those of the latter in each case.The author wishes to thank Mr Girish Nath, Lakshami Chemicals Pvt. Ltd., Phatuha (Patna), India, for providing pure samples of the herbicide for the present investigation. The receipt of financial assistance for this work in the form of a Higher Research Associateship Award to the author from the University Grants Commission, Govt. of India, New Delhi-110002 (Grant No. F/16-51/83), is thankfully acknowledged.     

Dissociation constants of the complexes between RNA-polymerase II and amanitins

Riassunto Sono state calcolate le costanti di dissociazione dei complessi fra la RNA-polimerasi II e la metil--amanitina, la -amanitina e la metil-aldoamanitina. La K _d è risultata essere 3.6×10^–9 M per la metil--amanitina e 3.2×10^–9 M per la -amanitina. La metil-aldoamanitina non si lega all'enzima.     

Dissociation-constants of metal-ion-complexes with alkaline phosphatase from pig kidney

Summary Using metal-ion buffers it was possible to remove Zn²⁺, Mg²⁺ and Mn²⁺ ions of pig kidney alkaline phosphatase reversibly. The dissociation constants obtained are K_EMg:4·10^–7 M, K_EMn:4·10^–8 M and K_EZn:8·10^–13 M (22°C, pH:9.6, :0.07).Acknowledgement: The authors thank Dr.H. U. Wolf for helpful suggestions and valuable discussion and MissH. Köth for technical assistance.     

Negative adsorption of anions by suspensions of bentonites

Résumé Nous avons étudié l'adsorption négative des anions I*O ₃ ^– et Cr*O ₄ ^–– à différents bentonites en fonction d'électrolytes additionnés. Pour les électrolytes NaCl et Na₂SO₄ les résultats sont en bon accord avec ceux deSchofield etMattson; nous avons étudié aussi l'effet de l'addition de solutions de CaCl₂; celles-ci produisent le même effet à des dilutions 20 fois plus grandes que les solutions de NaCl. Comme ceci ne peut pas être expliqué sur la base de la théorie deDebye-Hückel, nous avons appliqué la théorie exacte de la couche double; le facteur 20 mentionné plus haut mène à une valeur de=–75 mV. En introduisant cette valeur de, une représentation graphiques–1/c pour les résultats des expériences au Na-bentonite + solutions de NaCl, donne une surface spécifique de 1110 m²/g.     

Studies on hydrogen,halides and thiocyanate ions in dioxane-water mixtures at various temperatures

Summary The free enrgies of transfer (G _t ⁰ ) of H⁺, Cl^–, Br^–, I^– and SCN^– ions from water to 10, 20, 30 and 40% dioxanewater mixtures have been studied from potentiometric measurements. For anions the G _t ⁰ values are in the order Cl^–>Br^–>SCN^–>I^–.     

Experimental data on the energetic flux during glycolytic oscillations in yeast extracts

Calorimetric experiments were performed on yeast extracts in which glycolytic oscillations were occurring. High metabolic fluxes coincided with low amplitudes and with high frequencies in a temperature range from 283 to 303 K, yielding an activation energy ofE _a=76.8 kJ mol^–1 and a mean Q₁₀ value of 2.5±0.4. The calorimetrically determined reaction enthalpy _fH^0, of the glycolytic catabolism of glucose revealed two distinct groups of extract preparations, with no intermediate values. The values were –107.5±28.7 kJ mol^–1 and –30.8±5.7 kJmol^–1, respectively, while –100.0 kJ mol^–1 was predicted from theoretical calculations. Kreuzberg and Betz⁶ predicted rate limiting effects of GAPDH in oscillating extracts. However, when possible effects of GAPDH on frequency, number of oscillations or total heat production were examined, no influence of increasing or reducing the initial GAPDH concentration could be found. The results are discussed with reference to existing models of glycolytic oscillations.