Microbial biomass and activity in two cultivation systems on the SHIFT experimental area near Manaus.

In two different cultivation systems we investigated the microbial biomass and activity in the rhizosphere of Theobroma grandiflorum and Bactris gasipaes, two important crop plants in sustainable agriculture in Brazil during rainy and dry season 1998

Enzyme in Bewegung ? - Verlagerung von extrazellulären Enzymen mit dem Sickerwasser

Extrazelluläre Enzyme tragen wesentlich zum Umsatz organischen Materials im Boden bei. Durch die Bestimmung Ihrer Aktivität können Aussagen zum Nährstoffstatus und Umsatzbedingungen im Boden getroffen werden. Die meisten Studien, die sich bisher mit Aktivitäten von extrazellulären Enzymen beschäftigt haben, legten ihren Fokus auf die Rolle und Funktion der Enzyme im Nährstoffumsatz, wohingegen nur wenige Studien Verlagerungen von Enzymen, zum Beispiel mit dem Sickerwasserstrom untersuchten. Durch eine mögliche Verlagerung können extrazelluläre Enzyme in tiefere Horizonte des Bodens eingetragen werden und hier zum Abbau der nur in geringen Mengen vorhandenen organischen Substanz beitragen. Um diesen möglichen Eintrag abschätzen zu können, werden im Rahmen der SUBSOM-Forschergruppe Sickerwasserproben aus drei unterschiedlichen Tiefen (10, 50, 150cm) einer Braunerde unter Buchenwald (40km nordwestlich von Hannover, Niedersachsen) entnommen. Die Sickerwasserproben wurden mit Hilfe von Saugplatten aus drei am Standort eingebauten Lysimetern (Durchmesser: 1,5m; Tiefe: 2,00m) gewonnen und anschließend im Hinblick auf die Aktivität unterschiedlicher extrazellulärer Enzyme aus dem C-, N-, und P-Kreislauf im Labor analysiert. Vorläufige Ergebnisse zeigen, dass die Gesamtaktivität der extrazellulären Enzyme im Sickerwasser in allen Tiefen mit 0,59-371 pmol ml h-1 im Vergleich zum Boden sehr gering ist. Die Aktivitäten von β-Xylosidase und Leucine-Aminopeptidase konnten in allen Tiefen nachgewiesen werden, während Phosphatase nur in Tiefe 10 und 50cm aktiv war. Im oberen Unterboden (10cm) konnten keine Aktivitäten von Sulfatase, α-Glucosidase, β-Cellobiosidase, Arginin-Aminopeptidase and Tyrosin-Aminopeptidase gemessen werden, obwohl sie in der Tiefe 50 und 150cm wieder auftraten. Generell zeigte sich, dass extrazelluläre Enzyme im Sickerwasser aktiv sind und somit in tiefere Bodenhorizonte verlagert werden können und dort zum Nährstoffumsatz beitragen könnten

Vanadium (β-(Dimethylamino)ethyl)cyclopentadienyl Complexes with Diphenylacetylene Ligands

Reduction of the V(III) (β-(dimethylamino)ethyl)cyclopentadienyl dichloride complex [η5:η1-C5H4(CH2)2NMe2]VCl2(PMe3) with 1 equiv of Na/Hg yielded the V(II) dimer {[η5:η1-C5H4(CH2)2NMe2]V(µ-Cl)}2 (2). This compound reacted with diphenylacetylene in THF to give the V(II) alkyne adduct [η5:η1-C5H4(CH2)2NMe2]VCl(η2-PhC≡CPh). Further reduction of 2 with Mg in the presence of diphenylacetylene resulted in oxidative coupling of two diphenylacetylene groups to yield the diamagnetic, formally V(V), bent metallacyclopentatriene complex [η5:η1-C5H4(CH2)2NMe2]V(C4Ph4).

Quantitative trait loci conferring grain mineral nutrient concentrations in durum wheat 3 wild emmer wheat RIL population

Mineral nutrient malnutrition, and particularly deficiency in zinc and iron, afflicts over 3 billion people worldwide. Wild emmer wheat, Triticum turgidum ssp. dicoccoides, genepool harbors a rich allelic repertoire for mineral nutrients in the grain. The genetic and physiological basis of grain protein, micronutrients (zinc, iron, copper and manganese) and macronutrients (calcium, magnesium, potassium, phosphorus and sulfur) concentration was studied in tetraploid wheat population of 152 recombinant inbred lines (RILs), derived from a cross between durum wheat (cv. Langdon) and wild emmer (accession G18-16). Wide genetic variation was found among the RILs for all grain minerals, with considerable transgressive effect. A total of 82 QTLs were mapped for 10 minerals with LOD score range of 3.2–16.7. Most QTLs were in favor of the wild allele (50 QTLs). Fourteen pairs of QTLs for the same trait were mapped to seemingly homoeologous positions, reflecting synteny between the A and B genomes. Significant positive correlation was found between grain protein concentration (GPC), Zn, Fe and Cu, which was supported by significant overlap between the respective QTLs, suggesting common physiological and/or genetic factors controlling the concentrations of these mineral nutrients. Few genomic regions (chromosomes 2A, 5A, 6B and 7A) were found to harbor clusters of QTLs for GPC and other nutrients. These identified QTLs may facilitate the use of wild alleles for improving grain nutritional quality of elite wheat cultivars, especially in terms of protein, Zn and Fe

Lack of effect of lowering LDL cholesterol on cancer: meta-analysis of individual data from 175,000 people in 27 randomised trials of statin therapy

<p>Background: Statin therapy reduces the risk of occlusive vascular events, but uncertainty remains about potential effects on cancer. We sought to provide a detailed assessment of any effects on cancer of lowering LDL cholesterol (LDL-C) with a statin using individual patient records from 175,000 patients in 27 large-scale statin trials.</p> <p>Methods and Findings: Individual records of 134,537 participants in 22 randomised trials of statin versus control (median duration 4.8 years) and 39,612 participants in 5 trials of more intensive versus less intensive statin therapy (median duration 5.1 years) were obtained. Reducing LDL-C with a statin for about 5 years had no effect on newly diagnosed cancer or on death from such cancers in either the trials of statin versus control (cancer incidence: 3755 [1.4% per year [py]] versus 3738 [1.4% py], RR 1.00 [95% CI 0.96-1.05]; cancer mortality: 1365 [0.5% py] versus 1358 [0.5% py], RR 1.00 [95% CI 0.93–1.08]) or in the trials of more versus less statin (cancer incidence: 1466 [1.6% py] vs 1472 [1.6% py], RR 1.00 [95% CI 0.93–1.07]; cancer mortality: 447 [0.5% py] versus 481 [0.5% py], RR 0.93 [95% CI 0.82–1.06]). Moreover, there was no evidence of any effect of reducing LDL-C with statin therapy on cancer incidence or mortality at any of 23 individual categories of sites, with increasing years of treatment, for any individual statin, or in any given subgroup. In particular, among individuals with low baseline LDL-C (<2 mmol/L), there was no evidence that further LDL-C reduction (from about 1.7 to 1.3 mmol/L) increased cancer risk (381 [1.6% py] versus 408 [1.7% py]; RR 0.92 [99% CI 0.76–1.10]).</p> <p>Conclusions: In 27 randomised trials, a median of five years of statin therapy had no effect on the incidence of, or mortality from, any type of cancer (or the aggregate of all cancer).</p&gt

Bactris gasipaes H.B.K.: production factors in agro-ecosystems.

According with the studies realized the litter from peach palm (pupunha) contibutes with only 110 g/ha or 0,1% of total soil C to the C budget of the system. On the other hand it produces high quantities of root exudates. About 16.500 kg/ha C or 15% of total soil C respectively are released into the soil. Taking into account the C loss by microbial respiration and root respiration peach palm contributes with 10.700 kg/ha or 10% of total soil C respectively to the C budget of the system. Compared to C from root exudates the quantity of C from microbial biobass under peach palm is low. Only 45 kg/ha or 0,0004% of the total C originate from the microbial biomass

Estimating the number needed to treat from continuous outcomes in randomised controlled trials: methodological challenges and worked example using data from the UK Back Pain Exercise and Manipulation (BEAM) trial

Background Reporting numbers needed to treat (NNT) improves interpretability of trial results. It is unusual that continuous outcomes are converted to numbers of individual responders to treatment (i.e., those who reach a particular threshold of change); and deteriorations prevented are only rarely considered. We consider how numbers needed to treat can be derived from continuous outcomes; illustrated with a worked example showing the methods and challenges. Methods We used data from the UK BEAM trial (n = 1, 334) of physical treatments for back pain; originally reported as showing, at best, small to moderate benefits. Participants were randomised to receive 'best care' in general practice, the comparator treatment, or one of three manual and/or exercise treatments: 'best care' plus manipulation, exercise, or manipulation followed by exercise. We used established consensus thresholds for improvement in Roland-Morris disability questionnaire scores at three and twelve months to derive NNTs for improvements and for benefits (improvements gained+deteriorations prevented). Results At three months, NNT estimates ranged from 5.1 (95% CI 3.4 to 10.7) to 9.0 (5.0 to 45.5) for exercise, 5.0 (3.4 to 9.8) to 5.4 (3.8 to 9.9) for manipulation, and 3.3 (2.5 to 4.9) to 4.8 (3.5 to 7.8) for manipulation followed by exercise. Corresponding between-group mean differences in the Roland-Morris disability questionnaire were 1.6 (0.8 to 2.3), 1.4 (0.6 to 2.1), and 1.9 (1.2 to 2.6) points. Conclusion In contrast to small mean differences originally reported, NNTs were small and could be attractive to clinicians, patients, and purchasers. NNTs can aid the interpretation of results of trials using continuous outcomes. Where possible, these should be reported alongside mean differences. Challenges remain in calculating NNTs for some continuous outcomes