Growth characteristics, nitrogen uptake and enzyme activities of the nitrate-utilising ectomycorrhizal Scleroderma verrucosum

The growth characteristics and uptake capacities for NO3- and NH4+, as well as activities of nitrogen assimilating-enzymes have been determined in Scleroderma verrucosum. Biomass, grown on agar or liquid MMN media, was higher on nitrate. When S. verrucosum was grown in the presence of equal amounts of ammonium and nitrate, uptake rate for NH4+ was considerably higher than that of NO3-. In addition, it was found that a limitation in ammonium concentration was a prerequisite for nitrate uptake. Nitrate reductase was stimulated when the fungus was transferred from ammonium to nitrate containing media, indicating that the enzyme was inducible by nitrate and repressed by ammonium. Glutamine synthetase and NAD-glutamate synthase activities were clearly detected in S. verrucosum, while the NADP-glutamate dehydrogenase was almost undetectable. This is consistent with the view that ammonium assimilation occurs through the GS/GOGAT cycle in S. verrucosum

Investigation of CuIn1-xGaxSe2 thin films co-evaporated from two metal sources for photovoltaic solar cells

 CuIn1-xGaxSe2 (CIGS) thin films were grown by co-evaporation using two sources for the metal elements (Cu, Ga and In). A Mo coated soda lime glass substrates heated at 500 °C was used for the deposition. X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirm that these films are polycrystalline with a chalcopyrite structure and showed homogeneous grain size estimate about 25 nm. X-ray photoelectron spectroscopy (XPS) was performed to analyse the binding energy values of Ga3d and O1s onto CIGSe layers. The conductivity measurements in the temperature range of 40-400 K were carried out for 0.05≤ x ≤ 0.23. The effect of grain boundary scattering on the electrical transport played an important role in describing the transport processes in these films. The bowing factor is discussed taking into account the deposition techniques of CIGS films. It has been noticed that the open circuit voltage (Voc) is influenced by Ga content and the energy gap value of the absorber CIGS thin layers and yielded a poor efficiency of solar cells

Synthesis of a new series of sulfonamides containing isatin moiety

Im Rahmen der Ökoqualitätsverordnung (ÖQV) erhalten Schweizer Landwirte Direktzahlungen, wenn eine definierte Mindestanzahl seltener Arten auf ihrem Grünland stehen, wofür Transaktionskosten nur etwa in der Höhe wie bei konventionellen Agrarumweltprogrammen entstehen. Dieser Beitrag beschäftigt sich mit der Effektivität dieses outputorientierten Programms. Eine Konfiguralfrequenzanalyse zeigt, dass Landwirte, die an der ÖQV teilnehmen, mit nur geringer Wahrscheinlichkeit ihre Teilnahme an Agrarumweltprogrammen reduzieren. Es wird die Schlussfolgerung gezogen, dass outputorientierte Agrarumweltprogramme ein effizientes Mittel zur Erlangung ökologischer Qualität sind

Effect of novel phosphoramidate on growth and respiratory metabolism of Paramecium aurelia

The continuous increase in the number of new chemicals as well as the discharges of solid and liquid wastes triggered the need for simple and inexpensive bioassays for routine testing. In recent years, there has been increasing development of methods (particularly rapid tests) for testing environmental samples. This paper describes the quick toxic evaluation of a novel synthetic compound: Phosphoramidate derivative B at different concentrations (2, 4 and 8 μM) for 72 h on Paramecium aurelia. We showed that B concentrations affect the growth of Paramecium in concentration- dependent manner; also it decreases the growth rate and increases response percentage in concentration- dependent manner. The value of LC50 obtained for these protozoa was estimated at 4.9693 μM after 24 hours of exposure. The respiratory metabolism of protozoan is perturbed at three concentrations, noting that the oxygen consumption was significantly increased at high concentrations after 18 hours of exposure. The results indicate that the Paramecium toxicity assay could be used as a complementary system to rapidly elucidate the cytotoxic potential of insecticides. The major advantages associated with these tests are: inexpensive, simple, rapid and seem to be attractive alternatives to conventional bioassay

New pseudonucleosides containing chiral oxazolidin-2-ones and cyclosulfamides as aglycones: Synthesis and antiviral evaluation

9 - conference paper: Proceedings of the 17th International Roundtable of Nucleosides, Nucleotides, and Nucleic Acids MAR 07-SEP 07, 2006 Bern (SWITZERLAND)A series of chiral cyclosulfamides and oxazolidinon-2-ones have been synthesized starting from aminoacids. Regioselective substitution of these pseudopyrimidic heterocyles was carried out under Mitsunobu conditions. Best substitution results were obtained by preliminary deprotection of cyclosulfamides and their condensation with beta-D-ribofuranose. Chiral oxazolidin-2-ones were coupled directly with D-ribofuranose. All compounds were tested against HSV-2, VV and SV viruses. Two compounds 6b and 6e showed significant activities against HSV-type 1

A new family of 1,2,5-thiadiazolidine 1,1-dioxides: Synthesis, structure and antibacterial activity

International audienceA convenient synthesis of novel N-N’-substituted 1,2,5-thiadiazolidine 1,1-dioxides starting from amino acids isreported in five step (reduction, carbamoylation-sulfamoylation, intermolecular cyclization via the Mitsunobureaction and acylation). The newly synthesized compounds were characterized by IR, NMR and mass spectralanalysis. Some of the newly synthesized compounds (4c and 4d) were examined for their antibacterial activityagainst several strains of Gram-positive and Gram-negative bacteria

Crystal structure of 4-phenyl-piperazine-1-sulfonamide

1 - ArticleThe structure of 4-phenyl-piperazine-1-sulfonamide was determined by X-ray crystallography. The compound crystallized in a monoclinic system and was characterized as follows: P21/c, a = 24.1829(7), b = 9.5485(3), c = 9.7885(2)Å, β = 92.2337(16)°, Z = 8, V = 2258.55(11)Å3. The crystal structure was solved by direct methods and refined by full-matrix least-squares on F2 to final values of R1 = 0.0427 for 3206 reflections [I > 2σ(I)] and R1 = 0.0739, wR2 = 0.1083 for all the 4589 unique reflections. The crystal structure consists of layers of polar regions that enclose a sulfonamide function linked by hydrogen bonds and hydrophobic regions with π-π stacking interactions