349 research outputs found
The Arabidopsis NLP7 gene regulates nitrate signaling via NRT1.1-dependent pathway in the presence of ammonium.
Nitrate is not only an important nutrient but also a signaling molecule for plants. A few of key molecular components involved in primary nitrate responses have been identified mainly by forward and reverse genetics as well as systems biology, however, many underlining mechanisms of nitrate regulation remain unclear. In this study, we show that the expression of NRT1.1, which encodes a nitrate sensor and transporter (also known as CHL1 and NPF6.3), is modulated by NIN-like protein 7 (NLP7). Genetic and molecular analyses indicate that NLP7 works upstream of NRT1.1 in nitrate regulation when NH4+ is present, while in absence of NH4+, it functions in nitrate signaling independently of NRT1.1. Ectopic expression of NRT1.1 in nlp7 resulted in partial or complete restoration of nitrate signaling (expression from nitrate-regulated promoter NRP), nitrate content and nitrate reductase activity in the transgenic lines. Transcriptome analysis revealed that four nitrogen-related clusters including amino acid synthesis-related genes and members of NRT1/PTR family were modulated by both NLP7 and NRT1.1. In addition, ChIP and EMSA assays results indicated that NLP7 may bind to specific regions of the NRT1.1 promoter. Thus, NLP7 acts as an important factor in nitrate signaling via regulating NRT1.1 under NH4+ conditions
Entanglement characteristics of subharmonic modes reflected from cavity for type II second harmonic generation
Quantum fluctuation and quantum entanglement of the pump field reflected from
an optical cavity for type II second harmonic generation are theoretically
analyzed. The correlation spectra between the quadratures of the reflected
subharmonic fields are interpreted in terms of pump parameter, intracavity
losses and normalized frequency. Large correlation degrees of both amplitude
and phase quadratures can be accessed in a triple resonant cavity before the
pitchfork bifurcation occurs. The two reflected subharmonic fields are in an
entangled state with the quantum correlation of phase quadratures and
anticorrelation of amplitude quadratures. The proposed system can be exploited
to be a new source generating entangled states of continuous variables.Comment: 16 pages, 6 figures. submitted to Physical Review
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