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.     

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     

Biodegradation of bitumen used for nuclear waste disposal

Summary Studies have been carried out to test microbial degradation of bitumen used for encapsulating radioactive waste in Sweden. Microorganisms have been isolated that degrade bitumen. In ong-term tests under conditions simulating those in the silo part of the final repository for low-and intermediate-level radioactive waste, both aerobic and anaerobic degradation of bitumen has been found, equivalent to 0.6–1.5 moles CO₂/month·mg bitumen and 1.1–1.5 moles CO₂/month·mg bitumen, respectively.     

Alkaloide ausVinca minor L. Vincadin,Minovin und Vincorin

Summary The isolation and characterisation of three new alkaloids fromVinca minor L. is described: Vincadine C₂₁H₂₈N₂O₂, Minovine C₂₂H₂₈N₂O₂, and Vincorine C₂₂H₂₈N₂O₃ belonging to the indol- and dihydroindol alkaloids.

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VII. Mitteilung, VI. Mitt.: sieheJ. Mokrý I. Kompi, P. efovi, und. Bauer, Coll. Czech. Chem. Comm., im Druck.     

Role of adenosine A1 and A2 receptors in the regulation of aldosterone production in rat adrenal glands

Summary To investigate the roles of adenosine A₁ and A₂ receptors in the regulation of aldosterone production, we examined the effects of adenosine and adenosine agonists (N⁶-cyclohexyl adenosine; selective adenosine A₁ receptor agonist and 5-N-ethylcarboxamine adenosine; selective adenosine A₂ receptor agonist) on aldosterone and cyclic AMP production in rat adrenal capsular cells. Neither adenosine nor 5-N-ethylcarboxamine adenosine caused significant effects on basal aldosterone or cyclic AMP production. Also, adenosine (10^–3M) showed no consistent effects on aldosterone and cyclic AMP production induced by ACTH. On the other hand, N⁶-cyclohexyl adenosine exhibited a significant inhibition of basal aldosterone and cyclic AMP production at doses of 10^–4 M and 10^–3 M; furthermore, 10^–3 M N⁶-cyclohexyl adenosine inhibited aldosterone and cyclic AMP production stimulated by ACTH. These results suggest that adenosine A₁ receptors are coupled to and inhibit adenylate cyclase and may be involved in the inhibition of aldosterone production.     

Ammonia and amino acid transport across symbiotic membranes in nitrogen-fixing legume nodules

Biological nitrogen fixation involves the reduction of atmospheric N₂ to ammonia by the bacterial enzyme nitrogenase. In legume-rhizobium symbioses, the nitrogenase-producing bacteria (bacteroids) are contained in the infected cells of root nodules within which they are enclosed by a plant membrane to form a structure known as the symbiosome. The plant provides reduced carbon to the bacteroids in exchange for fixed nitrogen, which is exported to the rest of the plant. This exchange is controlled by plant-synthesised transport proteins on the symbiosome membranes. This review summarises our current understanding of these transport processes, focusing on ammonia and amino acid transport. Received 5 June 2000; revised 13 July 2000; accepted 14 July 2000     

Stretching activity in dogs intracisternally injected with a synthetic melanocyte-stimulating hexapeptide

Riassunto La iniezione endocisternale nel cane di dosi fino a 0.75 mg/kg del sale acetico dell'esapeptide H. Glu (NH₂)-Ist-Fen-Arg-Tript-Gli.OH, svolgente un'attività melanoforo-stimolante della intensità di 2 × 10⁵ U/g, induce delle tipiche crisi di stiramento, del tutto simili a quelle che si ottengono iniettando per la stessa via dell'ACTH o dell'MSH. Dosi di 1.5 mg/kg invece non inducono più crisi di stiramento ma deprimono notevolmente gli animali e determinano una intensa scialorrea. Sembra di poter ammettere che la struttura chimica responsabile dell'effetto sui melanociti sia anche responsabile dell'induzione delle crisi di stiramento.

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We are indebted to Dr.R. Schwyzer, CIBA Ltd., Basle (Switzerland), for the synthetic melanocyte-stimulating hexapeptide.     

Vincanorin und Vincarein,zwei neue Alkaloide ausVinca minor L.

Summary The isolation of two new alkaloids fromVinca minor L. (Apocynaceae) is described. Vincarein, C₂₁H₂₄N₂O₄, and Vincanorin, C₁₉H₂₂N₂O, both probably belong to the group of indol alkaloids.     

Does ammonium uptake influence xylem sap composition inPhaseolus vulgaris L. andGlycine max (L.) Merill?

The question of whether ammonium uptake influences the occurrence of ureides in legumes has been addressed in this study by investigating threeP. vulgaris genotypes as well as one cultivar ofGlycine max. All plants were raised in sand culture during the dry season in northern Thailand and irrigated daily with nitrogen-free nutrient solution, or the same solution containing 12 mol m^–3 nitrogen in the form of (NH₄)₂SO₄ or KNO₃, each treatment consisting of different proportions of either compound. Regression analyses of xylem sap composition relative to ammonium vs. nitrate supply of plants harvested at V4, R1 and R6 indicated close positive correlations of xylem amino nitrogen content and negative correlations with xylem nitrate content and ammonium supply. Statistically significant correlations between relative xylem ureide content and ammonium availability could be established for theP. vulgaris cultivar Brilliant up to stage R1, but not for the other plants investigated. It was concluded that at least for some genotypes of common bean a relationship exists between ureide production and ammonium uptake by the root system. Since the extent to which ureide production is stimulated remains quite small, its relevance to the xylem solute technique for measurement of N₂ fixation may be limited. Nevertheless, due to the possibility of large genotypic differences in the impact of ammonium on ureide production, this factor must be considered in calculations if N₂ fixation is to be determined in soils containing significant amounts of ammonium, e.g. in paddy fields.     

Chromosomal findings on eight species of EuropeanCryptocephalus

Summary Chromosome studies on 8 species of EuropeanCryptocephalus; C. aureolus Suffr.,C. capucinus Suffr.,C. globicollis Suffr.,C. hypochoeridis L.,C. moraei L.,C. rugicollis Ol.,C. sexpustulatus Vill., andC. violaceus Laich. have shown an identical karyotypic formula, 14^II+Xy_r, 2n=30. Most species ofCryptocephalus share 2n=30 chromosomes. The only interspecific differences are in the size of bivalents and in the sex-determining systems. The chromosomal interrelationships ofCryptocephalus with other allied groups are also discussed.     

Acute cold exposure increases the glucagon sensitivity of thermogenic metabolism in the rat

Summary Administration of glucagon to rats at 25°C had no effect upon their VO₂ while administration of noradrenaline or noradrenaline plus glucagon raised the VO₂-At 5°C, noradrenaline had no effect upon the cold-enhanced VO₂, while glucagon caused a rise of 13.7% implying increased glucagon sensitivity at 5°C. The glucagon-induced enhancement of VO₂ was abolished by concurrent administration of noradrenaline.     

Involvement of reactive oxygen species in the microsomal S-oxidation of thiobenzamide

Summary Superoxide dismutase, catalase and methional proved capable of inhibiting the microsomal oxidation of thiobenzamide, which is most probably catalyzed by the flavin-containing monooxygenase. This indicates that excited oxygen species (e. g.·O ₂ ^– , H₂O₂, ·OH) are involved in the catalytic cycle of this enzymatic reaction. CO, which inhibits the cytochrome P-450-dependent oxygen radical formation, had no effect on the oxidation reaction, suggesting that the source of the reactive oxygen species is not the microsomal mixed-function oxidase.     

Elemental sulphur (S<Subscript>8</Subscript>) in higher plants — biogenic or anthropogenic origin

In the course of investigating lipophilic air pollutants in the epicuticular wax ofPinus sylvestris L. needles, elemental sulphur, S₈, was found in all samples. An investigation was conducted to determined the origin of this substance. No correlation between the level of S₈ in the needles and human activities in the sampling area could be found, contrary to what would have been expected of an anthropogenic compound. The internal lipids ofP. sylvestris as well as the epicuticular wax of historical herbarium material and seedlings grown in clean, filtered air, and the epicuticular wax of several other species, both gymnosperms and angiosperms, also contained S₈. Quantitation of S₈ inP. sylvestris gave levels of 7.2±2.9 μg/g wax, 3.8±1.9 μg/g internal lipid and 0.43±0.17 μg/g total needle dry weight. Almost 0.1% of the total sulphur in pine needles is S₈, and approximately half of the total S₈ is found in the wax. The results suggest that S₈ is endogenous in many higher plants. A function for S₈ as part of an antifungal defence system is possible.     

Effects of pyrithiamine and oxythiamine on the thiamine content of tissues and blood pyruvate in mice

Riassunto La Piritiamina, somministrata per bocca in una singola dose di 0,5 mg a topolini di 12–14 g che ricevono 2 µg di tiaminapro die, non produce la sindrome neuromuscolare caratteristica dell'avitaminosi B₁ e non modifica nè la piruvicemia nè il livello di vitamina nel fegato, mentre lo fa abbassare nel muscolo e nel cervello. Se i topolini non ricevono tiamina, la stessa dose di Piritiamina dà perdita di peso, sindrome neuromuscolare in tutti gli animali trattati e cospicuo abbassamento del livello di vitamina B₁ nel cervello. Nelle stesse condizioni sperimentali, l'Ossitiamina, somministrataper os una sola volta in dosi di 0,5 e 2 mg, non dà alcuna sintomatologia neuromuscolare e non modifica nè il peso corporeo, nè il piruvato ematico, nè il contenuto in vitamina B₁ del muscolo e del cervello, solo abbassa il livello vitaminico del fegato.Questi risultati non sono in favore dell'ipotesi di una funzione della tiamina distinta da quella della cocarbossilasi.     

Refrigerating apparatus for medical use

Riassunto Si descrive un arnese refrigerante ad uso medico che raggiunge all'estremità della sonda operatoria la temperatura di — 89.7 C alle normali condizioni ambiente. Viene qui sfruttata la caduta di temperatura ottenuta dalla evaporazione localizzata e controllata del N₂O. è anche descritto un apparato derivato, utilizzante un sistema di liquefazione del N₂O, che successivamente viene fatto evaporare alla estremità della sonda operatoria.     

New contribution to the study of chromosomes of the European Cryptocephalinae (Coleoptera,Chrysomelidae)

Summary The chromosomes of three species ofPachybrachis and nine ofCryptocephalus chrysomelids were analyzed. The male meiotic bivalent formula ofP. azureus Suffr.,P. catalonicus Burl. andP. petitpierrei Daccordi is 7^II+Xy_r.Cryptocephalus sexmaculatus Ol. andC. vittula Suffr. have 13^II+Xy_p,C. bipunctatus L. 14^II+Xy_r,C. ochroleucus Steph. andC. ocellatus Drap. 14^II+Xy_p,C. crassus 01. 15^II+Xy_r,C. sulphureus 01. 15^II+Xy_p, the same number as inC. fulvus Goeze with 2n=32 chromosomes, whileC. primarius Har. has 19^II+Xy_p. The modal chromosome number inCryptocephalus is 2n=30 (about 60% of spp.), and most species are characterized their small chromosomes. The low variation found in the karyotypes of Cryptocephalinae along with their possible interrelationships with allied chrysomelid subfamilies are also discussed.     

Insecticidal effect of trans-2-nonenal,a constituent of carrot root

Summary Vapour of trans-2-nonenal killed the carrot fly larva,Psila rosae, with an LC₅₀ of 2.17 mg/24h. The aldehyde was identified in the essential oil of carrot in concentrations of up to 40 g/root.Special thanks are due to The Agricultural Institute, Dublin, for funding a proposal from M.F.R.     

Effects of photoperiod,temperature and testosterone-treatment on plasma T3 and T4 levels in the Djungarian hamster,Phodopus sungorus

Summary The effects of photoperiod, temperature and testosterone treatment on plasma T₃ and T₄ levels were investigated in the Djungarian hamster. Plasma T₃ level was affected by temperature (25°C<7°C) but not by photoperiod. Plasma T₄ level was affected by photoperiod (short day < long day) at 25°C. Administration of testosterone increased plasma T₄ level under short photoperiod at 25°C. Thus, higher plasma T₄ level under long photoperiod at 25°C might be induced by testosterone.     

Plant growth stimulation by inoculation with symbiotic and associative rhizosphere microorganisms

SelectedRhizobium bacteria, arbuscular mycorrhiza-forming (AM) fungi and associative bacteria have been shown to stimulate the growth of legumes, gramineae and cruciferae in field experiments on different soil types in temperate regions. A combination of microorganisms with different metabolic capacities (N₂-fixation, P-mobilization; production of phytohormones and antibiotics) can partly surpass the effect of single inoculations, or can produce a positive effect where single inoculations are ineffective. Growth stimulation by inoculation requires microorganisms with phytoeffective metabolic characteristics and the ability to survive in the rhizosphere during the growth period. Another prerequisite is an adequate supply of plant assimilates for the production of microbial phytoeffective metabolites. Type of inoculum, method of inoculation and agricultural measures can influence the effect of the inoculation. Research is necessary to extend our knowledge both of basic principles, and about using microorganisms in practice.     

Uptake of NO2 by plants grown at different salinity levels

Summary It is demonstrated that the uptake of nitrogen dioxide (NO₂) byPhaseolus vulgaris L. is decreased by the addition of sodium chloride (NaCl) to the root medium, as a result of increased diffusive resistance of the leaves. The NO₂-uptake rate constant measured kinetically was in agreement with the nitrite content of the leaves after the fumigation.