The influence of nutrient solution pH on the emission of N₂O and N₂ was investigated during cultivation of cucumbers in a closed-loop rockwool system. Between pH 4 and 7 these gaseous nitrogen losses ...increased from 1.6 to 21.1 % of the N fertilizer input. This was equivalent to average flux rates of 0.06 and 0.85 kg nitrogen per hectare greenhouse area and day, respectively. The N₂O/N₂ ratio was inversely related to the total gaseous nitrogen losses. At neutral pH dinitrogen was the main emission product, whereas more acidic conditions favoured the emission of nitrous oxide. The pH effects were probably not indirectly affected by root respiration or exudation as much as by a direct inhibition of the activity of denitrifying microorganisms due to high H⁺ concentrations since similar results were obtained in unplanted nutrient solution systems with the addition of glucose as carbon source. Despite the low microbial denitrification activity under acidic conditions, nitrogen balance deficits of up to one-fifth of the N input still occurred. It is suggested these losses were predominantly caused by chemodenitrification.
In this paper, we describe the synthesis and biological evaluation of highly substituted perhydropyrrolizines that inhibit the peptidyl‐prolyl cis/trans isomerase (PPIase) Pin1, an oncogenic target. ...The enzyme selectively catalyzes the cis/trans isomerization of peptide bonds between a phosphorylated serine or threonine, and proline, thereby inducing a conformational change. Such structural modifications play an important role in many cellular events, such as cell‐cycle progression, transcriptional regulation, RNA processing, as well as cell proliferation and differentiation. Based on computer modeling (Fig. 2), the new perhydropyrrolizinone derivatives (−)‐1a,b, decorated with two substituents, were selected and synthesized (Schemes 1–3). While enzymatic assays showed no biological activity, 15N,1H‐HSQC‐NMR spectroscopy revealed that (−)‐1a,b bind to the WW recognition domain of Pin1, apparently in a mode that does not inhibit PPIase activity. To enforce complexation into the larger active site rather than into the tighter WW domain of Pin1 and to enhance the overall binding affinity, we designed a perhydropyrrolizine scaffold substituted with additional aromatic residues (Fig. 5). A novel, straightforward synthesis towards this class of compounds was developed (Schemes 4 and 5), and the racemic compounds (±)‐22a–22d were found to inhibit Pin1 with Ki values (Ki = inhibition constant) in the micromolar range (Table 2). To further enhance the potency of these inhibitors, the optically pure ligands (+)‐22a and (+)‐33b,c were prepared (Schemes 6 and 7) and shown to inhibit Pin1 with Ki values down to the single‐digit micromolar range. According to 15N,1H‐HSQC‐NMR spectroscopy and enzymatic activity assays, binding occurs at both the WW domain and the active site of Pin1. Furthermore, the new synthetic protocol towards perhydropyrrolizines was extended to the preparation of highly substituted perhydroindolizine ((±)‐43; Scheme 8) and pyrrolidine ((±)‐48a,b; Scheme 9) derivatives, illustrating a new, potentially general access to these highly substituted heterocycles.
Gaseous nitrogen losses from a closed-loop rockwool system were investigated during the vegetative growth and the stem fruit stage of cucumbers. On average 12.4% of the N input were released in form ...of N₂O and N₂. This was equivalent to a mean emission rate of 0.62 kg nitrogen per hectare greenhouse area and day. The highest emission rates occurred during the stem fruit development as an increased root decay and an intensive substrate respiration came on. The proportion of N₂O in the gaseous nitrogen losses decreased with increasing N₂O+ N₂ evolution. On average it amounted to 9.6%. A comparison of different cucumber crops during the season showed that the gaseous nitrogen losses were nearly twice as high in the summer as in the autumn. Thus it proceeded almost parallel to the plant growth which also doubled. Furthermore, an effect of the substrate temperature is conceivable, since it was 3 -4°C higher in the radiation-rich summer-time. With increasing root density in the substrate gaseous nitrogen losses increased while the N₂O/N₂ ratio declined. Possible reasons for this were a greater rhizodeposition of easily decomposable organic substances, an accelerated oxygen consumption by root respiration and a high density of microorganisms in close vicinity to the roots. The growth of green algae on the substrate surface stimulated the production of N₂O.
An in vitro assay was designed to study the import of
3H-labeled phosphatidylinositol and phosphatidylcholine, respectively, from unilamellar vesicles into isolated mitochondria of the yeast,
...Saccharomyces cerevisiae. Both phospholipids reached the inner mitochondrial membrane. During import they were detected in contact sites between the outer and the inner mitochondrial membrane, supporting the notion that these zones are sites of intramitochondrial phospholipid transport. The uncoupler CCCP, the antibiotic adriamycin, and energy depletion caused by oligomycin and apyrase did not inhibit the transport of phosphatidylinositol and phosphatidylcholine into mitochondria.
Bacillus tusciae Bonjour & Aragno 1994 is a hydrogen-oxidizing, thermoacidophilic spore former that lives as a facultative chemolithoautotroph in solfataras. Although 16S rRNA gene sequencing was ...well established at the time of the initial description of the organism, 16S sequence data were not available and the strain was placed into the genus Bacillus based on limited chemotaxonomic information. Despite the now obvious misplacement of strain T2 as a member of the genus Bacillus in 16S rRNA-based phylogenetic trees, the misclassification remained uncorrected for many years, which was likely due to the extremely difficult, analysis-hampering cultivation conditions and poor growth rate of the strain. Here we provide a taxonomic re-evaluation of strain T2T (= DSM 2912 = NBRC 15312) and propose its reclassification as the type strain of a new species, Kyrpidia tusciae, and the type species of the new genus Kyrpidia, which is a sister-group of Alicyclobacillus. The family Alicyclobacillaceae da Costa and Rainey, 2010 is emended. The 3,384,766 bp genome with its 3,323 protein-coding and 78 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
Geschickt imitiert: Aryl‐1‐indanylketone erweisen sich als hocheffiziente, reversible und zellgängige Inhibitoren der humanen Peptidyl‐Prolyl‐cis/trans‐Isomerase Pin1. Aufgrund ihrer Struktur 1 wird ...angenommen, dass sie den Übergangszustand 2 der enzymatisch katalysierten Rotation um die imidische Peptidbindung vor dem Prolin nachahmen.
Haliangium ochraceum Fudou et al. 2002 is the type species of the genus Haliangium in the myxococcal family 'Haliangiaceae'. Members of the genus Haliangium are the first halophilic myxobacterial ...taxa described. The cells of the species follow a multicellular lifestyle in highly organized biofilms, called swarms, they decompose bacterial and yeast cells as most myxobacteria do. The fruiting bodies contain particularly small coccoid myxospores. H. ochraceum encodes the first actin homologue identified in a bacterial genome. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first complete genome sequence of a member of the myxococcal suborder Nannocystineae, and the 9,446,314 bp long single replicon genome with its 6,898 protein-coding and 53 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
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