Phased small-interfering RNAs (phasiRNAs) are a special class of small RNAs, which are generated in 21-or 24-nt intervals from transcripts of precursor RNAs. Although phasiRNAs have been found in a range of organisms, their biological functions in plants have yet to be uncovered. Here we show that phasiRNAs generated by the photopheriod-sensetive genic male sterility 1 (Pms1) locus were associated with photoperiod-sensitive male sterility (PSMS) in rice, a germplasm that started the two-line hybrid rice breeding. The Pms1 locus encodes a long-noncoding RNA PMS1T that was preferentially expressed in young panicles. PMS1T was targeted by miR2118 to produce 21-nt phasiRNAs that preferentially accumulated in the PSMS line under long-day conditions. A single nucleotide polymorphism in PMS1T nearby the miR2118 recognition site was critical for fertility change, likely leading to differential accumulation of the phasiRNAs. This result suggested possible roles of phasiRNAs in reproductive development of rice, demonstrating the potential importance of this RNA class as regulators in biological processes.photoperiod-sensitive male sterility | long-noncoding RNA | phasiRNA

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Post-transcriptional gene silencing in plants results from independent activities of diverse small RNA types. In anthers of grasses, hundreds of loci yield noncoding RNAs that are processed into 21- and 24-nucleotide (nt) phased small interfering RNAs (phasiRNAs); these are triggered by miR2118 and miR2275. We characterized these 'reproductive phasiRNAs' from rice (Oryza sativa) panicles and anthers across seven developmental stages. Our computational analysis identified characteristics of the 21-nt reproductive phasiRNAs that impact their biogenesis, stability, and potential functions. We demonstrate that 21-nt reproductive phasiRNAs can function in cis to target their own precursors. We observed evidence of this cis regulatory activity in both rice and maize (Zea mays). We validated this activity with evidence of cleavage and a resulting shift in the pattern of phasiRNA production. We characterize biases in phasiRNA biogenesis, demonstrating that the Pol II-derived 'top' strand phasiRNAs are consistently higher in abundance than the bottom strand. The first phasiRNA from each precursor overlaps the miR2118 target site, and this impacts phasiRNA accumulation or stability, evident in the weak accumulation of this phasiRNA position. Additional influences on this first phasiRNA duplex include the sequence composition and length, and we show that these factors impact Argonaute loading.

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Levofloxacin (LEV) is a fluoroquinolone antimicrobial agent. LEV also inhibits DNA synthesis and is bactericidal. The mechanisms of the interaction among LEV, DNA and Cu2+ are studied by fluorescence method. In the paper, the results show that LEV and Cu2+ can form binary complex, and also LEV and DNA can form complex mediated by Cu2+. The composition of the complex is determined. The affects to the reaction are also found.

A simple method is described for the electrostatic assembly of CdS nanoparticles onto oxidized aligned multiwalled carbon nanotubes (MWCNTs) in aqueous solution. The method is convenient to control and allows the formation of a stable, water-soluble suspension of CdS/aligned-MWCNT heterostructures. The prepared CdS/aligned-MWCNT heterostructures are characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD) and Fourier transform infrared spectrometry (FT-IR). The fluorescence and UV absorption spectral properties of the hybrid material demonstrate electron transfer from CdS nanoparticles to aligned-MWCNTs, which implies its potential applications in photovoltaic cells, photocatalysis, and solar energy conversion.

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