Nitrate reductase activity,biomass, yield,and quality in cotton in response to nitrogen fertilization

In the production of cotton (Gossypium hirsutum L.), nitrogen fertilization is one of the most costly crop practices, but important to reach high yields. However, high nitrogen (N) content in plants does not always translate into a high fibre production. One way of assessing the efficiency of the N fertilizer is through the enzymatic activity of the nitrate reductase (NR). This is a key enzyme in N assimilation, whose activity is regulated by a number of endogenous and exogenous factors that determine yield. The aim of this study was to assess the effect of N fertilization on yield, fibre quality, biomass, and NR enzymatic activity in vivo in the cotton variety Fiber Max 989. The evaluated application rates were 0, 50, 100, and 150 kg/ha of N, using urea as a source (46% N) in a randomizedblock design with three replicates. At harvest, the maximum yield of seed cotton and the greatest accumulation of total foliar biomass through time was reached after applying 150 kg N/ha. The different N-application rates did not affect the components of cotton-fibre quality. The activity of endogenous NR was greater on plants where 150 kg N/ha were applied. The highest cotton yield and N contents were obtained on these plants. Therefore, the NR activity in vivo could be used as a bioindicator of the N nutritional level in cotton.     

Design of a trial evaluating myocardial cell protection with cariporide, an inhibitor of the transmembrane sodium-hydrogen exchanger: the Guard During Ischemia Against Necrosis (GUARDIAN) trial

Background  

Direct myocardial cell protection in patients with unstable angina or evolving myocardial infarction (MI) could prevent cell necrosis or reduce its extent, and minimize the risk of MI and death associated with percutaneous coronary interventions (PCIs) and coronary artery bypass surgery. The myocardial NHE plays a critical role in mediating the progression of ischemia to necrosis by promoting intracellular accumulation of sodium and calcium in exchange for hydrogen. Blockage of the system in various experimental models of ischemia and reperfusion had a strong antinecrotic effect. The present paper describes a trial that was intended to investigate the potential clinical benefit of cariporide, a potent and selective inhibitor of the NHE, in a large spectrum of at-risk patients.     

Effects of delta-sleep-inducing peptide during ischemic injury of the rat brain

An anti-ischemic effect of the delta-sleep-inducing peptide (DSIP) was found in rats. The DSIP effect was more obvious than that of the MK-801. The data obtained is discussed considering a possible use of the DSIP for brain stroke prophylaxis.     

The Bacteriohopanepolyol Inventory of Novel Aerobic Methane Oxidising Bacteria Reveals New Biomarker Signatures of Aerobic Methanotrophy in Marine Systems

Aerobic methane oxidation (AMO) is one of the primary biologic pathways regulating the amount of methane (CH₄) released into the environment. AMO acts as a sink of CH₄, converting it into carbon dioxide before it reaches the atmosphere. It is of interest for (paleo)climate and carbon cycling studies to identify lipid biomarkers that can be used to trace AMO events, especially at times when the role of methane in the carbon cycle was more pronounced than today. AMO bacteria are known to synthesise bacteriohopanepolyol (BHP) lipids. Preliminary evidence pointed towards 35-aminobacteriohopane-30,31,32,33,34-pentol (aminopentol) being a characteristic biomarker for Type I methanotrophs. Here, the BHP compositions were examined for species of the recently described novel Type I methanotroph bacterial genera Methylomarinum and Methylomarinovum, as well as for a novel species of a Type I Methylomicrobium. Aminopentol was the most abundant BHP only in Methylomarinovum caldicuralii, while Methylomicrobium did not produce aminopentol at all. In addition to the expected regular aminotriol and aminotetrol BHPs, novel structures tentatively identified as methylcarbamate lipids related to C-35 amino-BHPs (MC-BHPs) were found to be synthesised in significant amounts by some AMO cultures. Subsequently, sediments and authigenic carbonates from methane-influenced marine environments were analysed. Most samples also did not contain significant amounts of aminopentol, indicating that aminopentol is not a useful biomarker for marine aerobic methanotophic bacteria. However, the BHP composition of the marine samples do point toward the novel MC-BHPs components being potential new biomarkers for AMO.     

MicroRNAs as Biomarkers for Acute Atrial Remodeling in Marathon Runners (The miRathon Study – A Sub-Study of the Munich Marathon Study)

Introduction

Physical activity is beneficial for individual health, but endurance sport is associated with the development of arrhythmias like atrial fibrillation. The underlying mechanisms leading to this increased risk are still not fully understood. MicroRNAs are important mediators of proarrhythmogenic remodeling and have potential value as biomarkers in cardiovascular diseases. Therefore, the objective of our study was to determine the value of circulating microRNAs as potential biomarkers for atrial remodeling in marathon runners (miRathon study).

Methods

30 marathon runners were recruited into our study and were divided into two age-matched groups depending on the training status: elite (ER, ≥55 km/week, n = 15) and non-elite runners (NER, ≤40 km/week, n = 15). All runners participated in a 10 week training program before the marathon. MiRNA plasma levels were measured at 4 time points: at baseline (V1), after a 10 week training period (V2), immediately after the marathon (V3) and 24h later (V4). Additionally, we obtained clinical data including serum chemistry and echocardiography at each time point.

Results

MiRNA plasma levels were similar in both groups over time with more pronounced changes in ER. After the marathon miR-30a plasma levels increased significantly in both groups. MiR-1 and miR-133a plasma levels also increased but showed significant changes in ER only. 24h after the marathon plasma levels returned to baseline. MiR-26a decreased significantly after the marathon in elite runners only and miR-29b showed a non-significant decrease over time in both groups. In ER miRNA plasma levels showed a significant correlation with LA diameter, in NER miRNA plasma levels did not correlate with echocardiographic parameters.

Conclusion

MiRNAs were differentially expressed in the plasma of marathon runners with more pronounced changes in ER. Plasma levels in ER correlate with left atrial diameter suggesting that circulating miRNAs could potentially serve as biomarkers of atrial remodeling in athletes.     

Elektronenmikroskopische Untersuchungen am Diaphragma der Maus nach einseitiger Phrenikotomie

Zusammenfassung Die Änderungen der Ultrastruktur im Diaphragma der Maus nach einseitiger Durchtrennung des N. phrenicus wurden im Abstand von 14 Std bis zu 6 Monaten nach Denervierung untersucht. Von den Degenerationserscheinungen nach Denervierung werden terminales Axon, Schwannsche Zelle und Muskulatur betroffen. In der ersten Degenerationsphase (1. bis 3. Tag) findet die Fragmentation des Axons durch die Schwannsche Zelle statt, die Agglutination der synaptischen Vesikel, die Lyse der Axon-Innenstruktur und die Resorption des Axons durch die Schwannsche Zelle. Die zweite Phase (3. bis 5. Tag) ist gekennzeichnet durch den Verlust der Schwannschen Zelle und die Bedeckung des sekundären Synapsenspaltes durch kollagenes Bindegewebe. Subneural-Apparat und Soleplate-Kerne bleiben während des Degenerationsprozesses erhalten. Im Sarcoplasma treten dichte Körper, Myelinfiguren, coated vesikel, multivesiculäre Körper und Lysosomen auf. Die Abbauprozesse im Muskel führen schließlich zur völligen Lyse der Struktur. Sechs Monate nach Denervierung sind die Muskelfasern durch Kollagenfasern ersetzt. Die Cholinesterase konnte bis zu vier Wochen nach Denervierung an der postsynaptischen Membran nachgewiesen werden. Die Ergebnisse werden mit den in der Literatur vorliegenden Befunden an degenerierenden Endplatten und Synapsen nach Nervendurchtrennung diskutiert.

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Electron-microscopical investigation of the mouse diaphragm after unilateral phrenicotomyI. The degenerating motor end-plate

Summary Ultrastructural changes of the denervated mouse diaphragm were studied 14 hours to 6 months following section of the n. phrenicus on the left side. Degeneration occurred in the terminal axon, the Schwann cell and in the muscle cell. In the first period (1–3 days) the fragmentation of the axon by the Schwann cell, the agglutination of synaptic vesicles, the lysis of the axon internal structure and the absorption of the axon by the Schwann cell are observed. The second period (3–5 days) is characterized by the loss of the Schwann cell and the covering of the secondary synaptic cleft by collagen fibrils. Subneural apparatus and soleplate nuclei persist during degeneration. In the sarcoplasm we found dense bodies, myelinated figures, coated vesicles, multivesicular bodies and lysosomes. The degenerating process in the muscle led to complete lysis of the structure. Six months after denervation the muscle fibers are replaced by collagen fibres. The cholinesterase is observable in the post-synaptic membrane until 4 weeks after denervation. The results are discussed in the light of literature on degenerating endplates and synapses after nerve section.

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Wir danken dem Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung (Nr. 4563) für die Unterstützung dieser Arbeit.     

Homologous cysteine proteinases of pathogenic and nonpathogenic Entamoeba histolytica. Differences in structure and expression.

A cDNA clone derived from the gene encoding a cysteine proteinase of pathogenic Entamoeba histolytica was isolated using an antiserum to the purified enzyme. This clone was used to identify the homologous clone in a cDNA library from nonpathogenic E. histolytica. Sequence analysis and comparison of the predicted amino acid sequences revealed a sequence divergence of 16%. Southern blot analyses indicated that (i) pathogenic isolates may contain more genes coding for these or related enzymes than nonpathogenic isolates, (ii) the structure and organization of these genes are conserved within each group of amoebae, and (iii) none of the genes is found in both pathogenic and nonpathogenic E. histolytica, underlining the notion that the two groups are genetically distinct. Northern blot analyses suggested that the cysteine proteinase is expressed by pathogenic isolates in substantially higher amounts than by nonpathogenic isolates. Overexpression of this enzyme may be an important factor in the pathogenicity of E. histolytica.     

Opacity determinants of Neisseria gonorrhoeae: gene expression and chromosomal linkage to the gonococcal pilus gene

In N. gonorrhoeae, the expression of pilus and opacity (Op) proteins can be switched on and off and a single cell apparently has a whole repertoire of genes to express many serologically distinguishable protein types. We describe the isolation of several different Op genes and of nonexpressing gene equivalents, all derived from isogenic gonococcal variants. In the E. coli host, Op proteins identical with those made in the respective N. gonorrhoeae strain are produced. The Op genes map near the pilus expression locus. Genomic blotting experiments with an Op gene probe reveal complex hybridization patterns but little heterogeneity among the genes of Op variants. It appears that colonial variation involving the Op protein of N. gonorrhoeae is based on minor sequence alterations, in contrast to the pilus variation system, in which changes in the expression can be evoked by substantial genomic rearrangements.     

Quasielastic light scattering from long rigid rods

The purpose of this work was to improve our understanding of quasielastic light scattering from long rigid rods (QL >> 1). For these scatterers, only small angular displacements are required to produce dephasing of the scattering light. This plus the fact that only rods lying perpendicular to Q contribute to the scattered light allow one to simplify the intermediate scattering function to an analytic form. This form is shown to be nonexponential, exhibiting (t)^?½ behavior at long delay times. This new scattering function can then be fit to experimental functions using standard methods.