Genetics. Getting closer to the whole picture     

Sauer U  Heinemann M  Zamboni N 《Science (New York, N.Y.)》2007,316(5824):550-551

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Synthesis, structure, and reactivity of an iron(V) nitride     

Scepaniak JJ  Vogel CS  Khusniyarov MM  Heinemann FW  Meyer K  Smith JM 《Science (New York, N.Y.)》2011,331(6020):1049-1052

Despite being implicated as important intermediates, iron(V) compounds have proven very challenging to isolate and characterize. Here, we report the preparation of the iron(V) nitrido complex, [PhB((t)BuIm)(3)Fe(V)≡N]BAr(F24) (PhB((t)BuIm)(3)(-) = phenyltris(3-tert-butylimidazol-2-ylidene)borato, BAr(F24) = B(3,5-(CF(3))(2)C(6)H(3))(4)(-)), by one electron oxidation of the iron(IV) nitrido precursor. Single-crystal x-ray diffraction of the iron(V) complex reveals a four-coordinate metal ion with a terminal nitrido ligand. M??bauer and electron paramagnetic resonance spectroscopic characterization, supported by electronic structure calculations, provide evidence for a d(3) iron(V) metal center in a low spin (S = 1/2) electron configuration. Low-temperature reaction of the iron(V) nitrido complex with water under reducing conditions leads to high yields of ammonia with concomitant formation of an iron(II) species.  相似文献   

Long-term fertilization effects on crop yields,soil fertility and sustainability in the Static Fertilization Experiment Bad Lauchstädt under climatic conditions 2001–2010     

Ines Merbach  Elke Schulz 《Archives of Agronomy and Soil Science》2013,59(8):1041-1057

The Static Fertilization Experiment Bad Lauchstädt (1902) consists of a crop rotation of sugar beets, spring barley, potatoes and winter wheat. Three farmyard manure (FYM) treatments and six mineral fertilizer treatments are combined orthogonally. Comparing the first and last decades, crop yields nearly doubled. In unfertilized plots, yields and N uptake by crops also increased when comparing first and last decades. On average for the decade 2001–2010, N uptake in unfertilized plots amounted 51.6 kg ha^?1. Although soil organic carbon (SOC) levels for unfertilized plots remain almost unchanged, SOC increases slowly in the most highly fertilized treatment, resulting in a gradual widening of differences in SOC between the most extreme treatments to 0.952%. Climate change and increased harvesting and root residues due to rising yields are suggested as an explanation. Except for the plot with the highest application of mineral and organic fertilizer, in all treatments more N was taken up by crops than was applied by fertilizers. Higher FYM input leads to more unfavourable N balances because N release from FYM cannot be controlled. Considering atmospheric N input, only in the exclusively mineral fertilized treatment is N balanced out. Similar results are found for C balances: the exclusively mineral fertilized treatment shows the most favourable C balance.  相似文献   

Stickstoffaufnahme und ‐Freisetzung durch Ruderalzönosen auf Dauerbrachen im Mitteldeutschen Trockengebiet     

Ines Merbach 《Archives of Agronomy and Soil Science》2013,59(5):417-430

Auf einer selbstbegrünten Dauerbrache ohne Pflegemaßnahmen (seit 1991) wurden in 4–6 wöchigen Abständen die Trockenmasse (TM) und die N‐Mengen im Pflanzenspross und in verschiedenen Streufraktionen untersucht. In Abhängigkeit von der dominierenden Pflanzenart wurden bis zu 2700 g TM/m² (= 270 dt TM/ha) gebildet. Darin waren bis zu 48 g N/m² (=48g N/ha) enthalten. Nach dem Absterben der Pflanzenbestände bildet sich Streu, die sich auf diesem Standort akkumulierte. In Abhängigkeit von der Güllebelastung des Bodens (hohe Belastung, geringe Belastung, unbelastet) wurde das Maximum der Streu‐TM mit 1345, 1506 bzw. 970 g TM/m² nach 4, 5 bzw. 6 Jahren Brachedauer erreicht. Die N‐Mengen in der Streu stiegen bis zum letzten untersuchten Jahr 1995 allmählich an. Die maximalen Jahresmittelwerte betrugen bei hoher Güllebelastung 27, bei geringer Güllebelastung 31 und ohne Gülle 10 g N/m²(= 270, 310 bzw. 100 kg N/ha). Die N‐Freisetzung aus der Streu begann noch im gleichen Jahr. Sie war im Wesentlichen auf der unbelasteten Parzelle nach 2 Jahren, auf den Gülleparzellen nach 3 Jahren abgeschlossen. Zukünftig müssen die Teilprozesse der N‐Freisetzung aus der Streu und ihre Wechselwirkungen sowie der Einbau des unkrautbürtigen? in die Boden‐N‐Fraktionen und die Wiederaufnahme durch die nächsten Pflanzengenerationen intensiver untersucht werden.  相似文献   

A new approach to kelp mariculture in Chile: production of free-floating sporophyte seedlings from gametophyte cultures of Lessonia trabeculata and Macrocystis pyrifera     

Renato Westermeier  David Patiño  Maria Ines Piel  Ingo Maier  & Dieter G Mueller 《Aquaculture Research》2006,37(2):164-171

Substantial amounts of Macrocystis and Lessonia are traditionally harvested and exported from Chile as raw material for alginate. Because of intense mariculture of abalone (Haliotis ssp.), herbivorous molluscs that feed on brown kelps, pressure on local populations of Macrocystis and Lessonia has increased to critical levels within the past 5 years, strongly supporting efforts to produce algae maricultured biomass. Here, we present our results on the development of new techniques for large‐scale kelp mariculture in Chile. We have abandoned the traditional technique of direct spore seeding onto inoculation lines. Instead, we used gametophyte cultures that were manipulated to enter gametogenesis and to produce synchronous batches of 10⁴–10⁵ embryos. Juvenile sporophytes were cultured under permanent aeration and agitation, floating unattached in contamination‐free glass bottles up to 10 L, plexiglass cylinders and 800 L greenhouse tanks. When holdfast initials were formed at a size of 8 cm, the sporophytes were spliced into Nylon rope fragments and transferred to the sea. Twelve months after initiation of gametogenesis in the laboratory, Macrocystis pyrifera attained 14 m length and 80 kg fresh weight m^?1 line in the sea. For Lessonia trabeculata 6 months after gametogenesis initiation, 0.25 kg fresh weight m^?1 was attained in the sea.  相似文献   

Trans-synaptic Eph receptor-ephrin signaling in hippocampal mossy fiber LTP     

Contractor A  Rogers C  Maron C  Henkemeyer M  Swanson GT  Heinemann SF 《Science (New York, N.Y.)》2002,296(5574):1864-1869

The site of induction of long-term potentiation (LTP) at mossy fiber-CA3 synapses in the hippocampus is unresolved, with data supporting both pre- and postsynaptic mechanisms. Here we report that mossy fiber LTP was reduced by perfusion of postsynaptic neurons with peptides and antibodies that interfere with binding of EphB receptor tyrosine kinases (EphRs) to the PDZ protein GRIP. Mossy fiber LTP was also reduced by extracellular application of soluble forms of B-ephrins, which are normally membrane-anchored presynaptic ligands for the EphB receptors. The application of soluble ligands for presynaptic ephrins increased basal excitatory transmission and occluded both tetanus and forskolin-induced synaptic potentiation. These findings suggest that PDZ interactions in the postsynaptic neuron and trans-synaptic interactions between postsynaptic EphB receptors and presynaptic B-ephrins are necessary for the induction of mossy fiber LTP.  相似文献   

Antibacterial Polyketides from the Marine Alga-Derived Endophitic Streptomyces sundarbansensis: A Study on Hydroxypyrone Tautomerism     

Ibtissem Djinni  Andrea Defant  Mouloud Kecha  Ines Mancini 《Marine drugs》2013,11(1):124-135

Polyketide 13 [=2-hydroxy-5-((6-hydroxy-4-oxo-4H-pyran-2-yl)methyl)-2-propylchroman-4-one] and three related known compounds 7, 9 and 11 were obtained and structurally characterized from Streptomyces sundarbansensis strain, an endophytic actinomycete isolated from the Algerian marine brown algae Fucus sp. Compound 13 was obtained as the major metabolite from optimized culture conditions, by using Agar state fermentation. Due to tautomeric equilibrium, 13 in CD₃OD solution was able to incorporate five deuterium atoms, as deduced by NMR and ESI-MS/MS analysis. The 2-hydroxy-γ-pyrone form was established for these metabolites based on the comparison of their experimental IR spectra with the DFT calculated ones, for both the corresponding 4-hydroxy-α-pyrone and 2-hydroxy-γ-pyrone forms. During antibacterial evaluation, compound 13 stood out as the most active of the series, showing a selective activity against the gram positive pathogenic methicillin-resistant S. aureus (MRSA, MIC = 6 μΜ), with a bacteriostatic effect.  相似文献   

Diversity of five glutenin loci within durum wheat (Triticum turgidum L. ssp. durum (Desf.) Husn.) germplasm grown in Algeria     

Ines Bellil  Ouahiba Hamdi  Douadi Khelifi 《Plant Breeding》2014,133(2):179-183

The HMW and B‐LMW glutenin subunits composition of 120 durum wheat germplasm grown in Algeria was examined using SDS‐PAGE. All together, 39 glutenin patterns were detected, including eight for HMW and 21 for B‐LMW glutenin subunits. Twenty‐six different alleles were identified for the five glutenin loci studied, that is, Glu‐A1 (3), Glu‐B1 (7), Glu‐A3 (5), Glu‐B3 (9) and Glu‐B2 (2). Two new alleles were found at Glu‐B3 locus: Glu‐B3new₁ encodes for five subunits (7 + 8 + 14 + 16 + 18) and Glu‐B3new₂ codes for five subunits (4 + 6* + 12 + 15 + 15*), of which subunit 15* with mobility between bands 15–16 was not described previously. At the Glu‐1 loci, the Glu‐A1c/Glu‐B1e allelic composition was predominant. For the B‐LMW glutenins, the most common allelic composition was Glu‐A3a/Glu‐B3a/Glu‐B2a. The collection analysed shows glutenin alleles and allele combinations related to high gluten strength. This information could be useful to select varieties with improved quality and also as a source of genes to develop new lines when breeding for quality.  相似文献   

Phenotypical and biochemical characterisation of resistance for parasitic weed (Orobanche foetida Poir.) in radiation‐mutagenised mutants of chickpea          下载免费PDF全文

Ines Brahmi  Yassine Mabrouk  Guillaume Brun  Philippe Delavault  Omrane Belhadj  Philippe Simier 《Pest management science》2016,72(12):2330-2338

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Identification of virulence factors by multiplex PCR in Escherichia coli isolated from calves in Minas Gerais, Brazil     

Andrade GI  Coura FM  Santos EL  Ferreira MG  Galinari GC  Facury Filho EJ  de Carvalho AU  Lage AP  Heinemann MB 《Tropical animal health and production》2012,44(7):1783-1790

In this study, multiplex PCR was employed to investigate the virulence factors of Escherichia coli strains isolated from 60-day-old calves. Faecal samples were collected from 54 calves at 12 dairy farms in the state of Minas Gerais, Brazil. A total of 156 isolates were obtained after culture and microbiological isolation and were tested by multiplex PCR for the presence of genes encoding toxins (Stx1, Stx2 and STa) and adherence factors (intimin, F41 and F5). Seventy of 156 isolates were positive for at least one virulence factor: ten (14.3?%) from diarrhoeic animals and 60 (85.7?%) from healthy calves. The virulence markers identified were: Stx1 (82.8?%), eae (24.3?%), F41 (11.4?%), F5 (10?%), STa (4.28?%) and Stx2 (4?%). In diarrhoeic animals, Stx1 (70?%) and F41 (30?%) were identified, while Stx1 (83.3?%), eae (28.3?%), F41 (8.3?%), F5 (11.6?%), STa (5?%) and Stx2 (1.6?%) were detected in isolates from healthy calves. Mixed infections with pathotypes Shiga toxin-producing E. coli (STEC)/enteropathogenic E. coli, STEC/enterohaemorrhagic E. coli and STEC/other (eae/F5, Stx1/STa) were detected in five healthy calves. Pathogenic E. coli were identified in 59.26?% of all calves and on 75?% of the dairy farms studied, not only in diarrhoeic (five of six) but also in healthy calves (27 of 48), which demonstrates the importance of this agent in the aetiology of diarrhoea in calves in the state of Minas Gerais.  相似文献