Active microbial sulfur disproportionation in the Mesoproterozoic

The environmental expression of sulfur compound disproportionation has been placed between 640 and 1050 million years ago (Ma) and linked to increases in atmospheric oxygen. These arguments have their basis in temporal changes in the magnitude of 34S/32S fractionations between sulfate and sulfide. Here, we present a Proterozoic seawater sulfate isotope record that includes the less abundant sulfur isotope 33S. These measurements imply that sulfur compound disproportionation was an active part of the sulfur cycle by 1300 Ma and that progressive Earth surface oxygenation may have characterized the Mesoproterozoic.     

Barium Xenate

Barium xenate was prepared by the addition of barium hydroxide to xenic acid. The resulting white amorphous precipitate was shown by elementary analysis to be Ba(3)XeO(6).     

Chemical and Mineralogical Properties of Norwegian Alum Shale Soils,with Special Emphasis on Heavy Metal Content and Availability

Abstract

Alum shale and till soils overlying alum shale bedrock were analysed for aqua regia and NH₄OAc/EDTA extractable Pb, Cu, Zn, Ni, Mn and Cd. The means of these determinations were compared with those of Norwegian, Finnish and Swedish non-alum shale soils. Alum shale soils seemed to contain higher amounts of both total and easily extractable Cu, Zn, Ni and Cd. Total Pb content also seemed to be higher in the alum shale soils. The relative availability of Cd, Ni and Mn, expressed as the ratio of NH₄OAc/EDTA to aqua regia extractable, was found to be greater than that of Pb, Cu and Zn in the alum shale and till soils.     

Glyphosate adsorption on synthetic allophanes and halloysite: Effects of pH and mineral properties

Background

Glyphosate (GLP) is a widely used herbicide with possible adverse effects on human health and the environment. In soils, GLP strongly adsorbs on clay-sized minerals, depending on pH, the amount of organic carbon, as well as the contents and properties of Al and Fe oxyhydroxides and clay minerals. Many clay-sized minerals have already been investigated regarding GLP adsorption behavior, but information on minerals commonly found in volcanic soils is still lacking.

Aim

The aim of this study was to investigate for the first time the pH-dependent adsorption of GLP on allophane and halloysite, typical minerals found in volcanic soils.

Methods

GLP adsorption was studied in batch experiments at three pH values (5, 6, and 7). Synthetic allophanes with two different initial Al:Si ratios (1.4 and 1.8) and a halloysite were used as adsorbents.

Results

The adsorption capacity (AC) increased with rising Al:Si ratio and decreasing pH. The AC of allophane was significantly higher than that of halloysite. GLP adsorption on allophane was larger than that reported for other clay minerals and Al and Fe oxyhydroxides, especially at low pH. The AC of halloysite was higher than reported for most other clay minerals.

Conclusion

Different mineral formation pathways in volcanic soils, notably the formation of halloysite versus allophanes, strongly affect the soils’ retention capacity for GLP. The high AC of allophanes may induce the low mobility of GLP in allophane-containing soils. Long-term use of GLP may accumulate the herbicide in these soils with potential effects on biodiversity and ecosystem services.     

Variation in content of Ω3 fatty acids in farmed Atlantic salmon,with special emphasis on effects of non-dietary factors

The main aim of the present study was to examine the impact of some biological and environmental factors on the lipid and fatty acid compositions of farmed Atlantic salmon (Salmo salar), with special emphasis on 3 fatty acids. Two year groups of salmon at nine fish farms distributed along the Norwegian coast were fed the same diet and were sampled every second month. The data are believed to give a representative characterization of lipid and fatty acid content of salmon farmed in Norway.Multiple regression analysis revealed that variation in lipid content and body weight explained 80% of the variation found in 3 fatty acids in farmed salmon, and 22:6 3 showed greater variation than other 3 fatty acids. Further analysis of lipid-corrected values revealed only minor effects of latitude on the per cent content of highly unsaturated 3 fatty acids, and hardly any effect of seawater temperature, with the exception of 22:6 3, which decreased slightly with increasing temperature.The per cent 22:6 3 in the fillet became gradually reduced with increasing fish age and body weight, whereas the content of 20:5 3 and other 3 fatty acids remained relatively constant. The per cent content of 22:6 3 of young salmon was higher than in the feed, but approached the feed value gradually as body weight increased. The lipid content of the salmon increased with fish age, and the absolute quantitative contents of both 22:6 3 and 20:5 3 increased meanwhile, even though the per cent content of 22:6 3 decreased quite pronouncedly.The per cent 22:6 3 and other 3 fatty acids was higher in wild than in farmed salmon, but the absolute quantitative content was higher throughout in farmed salmon, which had higher lipid contents. The 3/6 ratio, which is important in human health evaluation, was lower in farmed than in wild salmon. The large flexibility of 3 fatty acids and lipid content of farmed salmon leave us with the option of producing a wide variety of salmon qualities requested by the market. Both per cent and absolute quantitative 3 contents, as well as the 3/6 ratio, may readily be manipulated.     

Ein Beitrag zum Einsatz des Wachstumsregulators Chlorcholinchlorid (CCC) im Gemüsebau

Zusammenfassung An Hand von Versuchen in Mitscherlich-Gefäßen wurde die Wirkung von CCC auf verschiedene Nahrungspflanzen hauptsächlich hinsichtlich Rückstandsbildung untersucht. Neben Gewächshausversuchen sollte bei Kohlrabi ein Phytotronversuch Auskunft über den Einfluß nicht ausreichender Lichtintensität auf die Rückstandsbildung geben.Die Ergebnisse lassen sich wie folgt zusammenfassen: Die Höhe der Rückstände hängt in überwiegendem Maße von der Dosierung (25–250 mg/Pflanze) ab. In den haushaltsüblich verwertbaren Anteilen betragen die Rückstände bei Kohlrabi 1.00–1.50 ppm (Sorte Rogglis Weißer Treib) bzw. 1.65–2.15 ppm (Ozean), bei Blumenkohl (Delfter Markt) 0.50–1.61 ppm, in den Tomatenfrüchten (Eurocross A) reichen sie von 0.97–24.70 ppm. Die Rückstandshöhe sinkt bei Tomaten mit steigender Insertion der Fruchtstände von 6.96 auf 2.50 ppm vom 1. zum 4. bzw. 5. Fruchtstand bei einer CCC-Gabe von 50 mg/Pflanze ab. Außerdem beeinflußt der Behandlungszeitpunkt die Rückstandshöhe. Applikation durch Spritzen (Blattbehandlung) führt im Vergleich zur Behandlung durch Gießen (Bodenbehandlung) bei Blumenkohl (+70% bei 50 mg CCC/Pflanze) und Tomatenfrüchten (+300% bei 50, 125 und 250 mg CCC/Pflanze) zu höheren Rückständen.

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A contribution to the application of the Plant-Growth Regulator Chlorocholine chloride (CCC) in vegetable crops1. Communication: Determination of residues of chlorocholine chloride in kohlrabi, cauliflower, and tomatoes

Experimental work with chlorocholine chloride (CCC) on some vegetables carried out in Mitscherlich pots and grown chiefly in a greenhouse, to a smaller extent in a phytotrone gave the following results:Residues of CCC in levels corresponding to the doses applicated in the experiments (25 to 250 mg CCC/plant) were detected in edible portions of kohlrabi (cultivars: Rogglis Weißer Treib, 1,00–1.50 ppm; Ozean, 1.65–2.15 ppm), cauliflower (Delfter Markt, 0.50–1.61 ppm) and in the fruits of tomatoes (Eurocross A, 0.97–24.70 ppm). Residues decrease in fruits gradually towards the plant's top ranging from 6.96 to 2.50 ppm by an application rate of 50 mg CCC/plant. On the other hand, levels of residues in tomatoes are influenced by the time of application. Spraying (leaf treatment) leads to higher levels of residues in cauliflower (+70% at a rate of 50 mg) and tomato fruits (+300% at a rate of 50, 125 and 250 mg CCC) than sprinkling (soil treatment) does.

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Résumé Essais en vase de Mitscherlich sur l'action du CCC sur légumes, et sur la rémanence. Le chou-rave a été étudié en serres et en phytotron, de manière à mettre en évidence l'effet d'éclairements insuffisants sur la rémanence.Voici un résumé des essais. Le taux de rémanence dépend essentiellement de la quantité de produit appliqué (25 à 250 mg par pied). Dans les parties normalement consommées, les résidus qui persistent dans le chou-rave (Brassica gangylodes) varient de 1 à 1,5 ppm (Variété Rogglis à pousse blanche), de 1,65 à 2,15 (Variété Océan); chez les choufleur (Marché de Delft), de 0,50 à 1,61, chez la tomate (Eurocross A), 0,97 à 24,7 ppm. Le taux de résidus diminue, dans la Tomate, du bas vers le haut de la tige, et cela de 6,96 à 2,5 ppm de la 1^ère à la 4^e ou 5^e grappe de fruits, pour une application de 50 mg CCC par pied.Une application par aspersion (traitement des feuilles) détermine des taux de résidus beaucoup plus élèves que le traitement constitué par l'arrosage du sol: + 70% chez les chou-fleur, pour 50 mg CCC par plante, + 300% pour des fruits de tomates (50, 125, 250 mg CCC/pied),

     

Timing, light availability and vigour determine the response of Abies alba saplings to leader shoot browsing

Herbivore browsing on tree saplings is a common phenomenon that can cause damage particularly on preferred species. In this study, the combined effects of light availability and timing of browsing on the response of 9-year-old Abies alba saplings were tested experimentally. Leader shoot clipping was applied before budburst, shortly after budburst or in autumn on saplings grown in full light or under artificial shade. Timing of clipping, light availability and tree vigour (expressed as height and tree ring width before clipping) had an effect on the height after clipping. After clipping in autumn or before budburst, fast-growing fir saplings bent up twigs to form new leader shoots and overcompensated height loss; saplings characterised by intermediate growth rates formed new shoots out of regular visible lateral buds; and slow-growing saplings had no new shoot in the first year after clipping, such that the clipping-induced height difference even increased over time. Saplings clipped shortly after budburst elongated the remaining part of the shoot in the first year and developed shoots out of the most distal lateral buds in the second growing season, leading to complete height compensation. Multi-trunking was typical for all clipped trees. We conclude that the microscale conditions under which a tree is growing (i.e. which affect tree vigour) are highly important for determining whether the height reduction imposed by browsing is offset by overcompensation or increases over time relative to unclipped trees. This response can partly be influenced by forest management via enhancing tree vigour via the light regime.     

Isolation,Structure Elucidation and Total Synthesis of Lajollamide A from the Marine Fungus Asteromyces cruciatus

The marine-derived filamentous fungus Asteromyces cruciatus 763, obtained off the coast of La Jolla, San Diego, USA, yielded the new pentapeptide lajollamide A (1), along with the known compounds regiolone (2), hyalodendrin (3), gliovictin (4), ¹N-norgliovicitin (5), and bis-N-norgliovictin (6). The planar structure of lajollamide A (1) was determined by Nuclear Magnetic Resonance (NMR) spectroscopy in combination with mass spectrometry. The absolute configuration of lajollamide A (1) was unambiguously solved by total synthesis which provided three additional diastereomers of 1 and also revealed that an unexpected acid-mediated partial racemization (2:1) of the L-leucine and L-N-Me-leucine residues occurred during the chemical degradation process. The biological activities of the isolated metabolites, in particular their antimicrobial properties, were investigated in a series of assay systems.