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Dithienylethenes 1 and 2 , consisting of three photochromic units linked by imidazole bridges, together with its N-methylated derivatives 3 and 4 , have been synthesized. Their photochromic properties and fluorescence behaviors have also been investigated in solution by irradiation with various wavelengths of UV light. It was found that the dithienylethene 1 showed selective photochromism, indicated by the fluorescence change upon irradiation with 365 nm and 302 nm light. However, dithienylethenes 2 , 3 and 4 only underwent a photocyclization reaction in the middle switchable unit under the same conditions. Moreover, for dithienylethenes 2 and 4 , introduction of fluorine atoms on the cyclopentene evidently enhanced the photochromic properties compared with perhydro-substituted dithienylethenes 1 and 3 . And dithienylethene 3 could act as one potential fluorescent molecular switch.

Implantation with low-energy ion beam can induce various plant biological effects including stimulation, damage and mutation. But the adaptive mechanism altering gene expression in response to this stressor in plant is not fully understood. A highly thorough and comprehensive analysis to investigate the general-key genes responsive to implantation with low-energy ion beam in plant is important to understand the diverse mechanism. We used Agilent Rice Gene Expression Microarray to investigate the overlap differentially expressed genes between two independent implantation experiments underlying three ion fluences. Our microarray data showed that 26 up-regulated overlap genes and 6 down-regulated overlap genes were observed. The Gene Ontology terms analysis showed that genes with functions including kinase, transporter, acceptor, transcription regulation were involved in signaling and response biological processes in rice responding to the implantation with ion beam. Our data also implied that ABA signal transduction pathway is involved in response to ion-beam implantation in rice. The RiceNet co-expressed network analysis showed the direct and indirect co-expressed linkages among these up-regulated genes, which suggested some signal transduction pathways should be involved in this response and remained unclear. Our microarray data revealed the general and key genes responsive to the stress of implantation with low-energy ion beam during the rice germination. These data provide information on the candidate genes for further elucidation regarding the molecular mechanisms of the biological effects of ion-beam implantation and its application for improvement of corn. Key words: Microarray; key genes responsive to implantation of low-energy N+ ion beam; Rice

In order to understand the molecular mechanism of the ion-implantation biological effects, we analyzed genes expression profiles in rice seedlings from the seeds implanted with the nitrogen ion beam, using the Agilent Rice Oligo Microarray (4×44) Genome Array. Rice seeds were implanted by the nitrogen ion beam with 40 Kev energy in dose 6×1017 N+/cm2. Total RNA, from the seedlings 96h after the germination, was used to genechip analysis. The vigor index was measured at 10days after the germination. The results of measuring of the vigor index showed that smaller-dose implantation of the nitrogen ion beam (6×1017 N+/cm2) promoted the vigor index (P 2 and P value

Mutagenesis and retrotransposons have a close relationship, but little attention has been paid yet to the activity of retrotransposons produced by physical mutagens. The variation of retrotransposon WIS 2–1A activity in wheat (Triticum aestivum L.) embryos at three different growth times (30 h, 45 h and 60 h) was investigated after they had been treated with N+ implantation in a vacuum of 5 × 10−2 Pa and irradiation by 60Coγ-ray respectively. For each of the three growth times the expression of WIS 2–1A showed almost entirely a same trend of downregulation, upregulation, then downregulation, and upregulation again with the increase in dose of N+ implantation, but the expression appeared irregular with the increase in irradiation of 60Coγ-ray. In conclusion, the acutely activating effect of WIS 2–1A stimulated by vacuum and high dose N+ implantation within a shorter incubation time may provide a convenient tool to advance the research on mutagenic breeding and function genes.

Retrotransposon-like elements are major constituents of most eukaryotic genomes. For example, they account for roughly 90% of the wheat (Triticum aestivum) genome. Previous study on a wheat strain treated by low-energy N+ ions indicated the variations in AFLP (Amplified Fragment Length Polymorphism ) markers. One such variation was caused by the re-activation of Ty1-copia-like retrotransposons, implying that the mutagenic effects of low-energy ions might work through elevated activation of retrotransposons. In this paper an expression profile of Ty1-copia-like retrotransposons in wheat treated by low-energy N+ ions is reported. The reverse transcriptase (RT) domains of these retrotransposons were amplified by reverse-transcriptional polymerase chain reaction (RT-PCR) and sequentially cloned. 42 and 65 clones were obtained from the treated (CL) and control materials (CK), respectively. Sequence analysis of each clone was performed by software. Phylogeny and classification were calculated responding to the sequences of the RT domains. All the results show that there is much difference in the RT domain between the control sample and the treated sample. Especially, the RT domains from the treated group encode significantly more functional ORF (open reading frames) than those from the control sample. This observation suggests that the treated sample has higher activation of retrotransposons, possibly as a consequence of low-energy ion beam irradiation. It also suggests that retrotransposons in the two groups impact the host gene expression in two different ways and carry out different functions in wheat cells.

In order to investigate the overall characteristics of the transcript profiles associated with these puzzling biological effects. We used the Agilent Rice Oligo Microarray to learn the molecular mechanism in rice responding to ion-implantation. The analysis of the genechip array shows that there were 982 transcripts expressed differentially (fold change > 2 and P value < 0.05) including 429 up-regulated transcripts and 553 down-regulated transcripts under the dose3 6×1017 N+/cm2. Gene ontology analysis of the microarray data indicates that the up-regulated genes are belonged to five molecular functions, including three cellular component and one metabolic process (oxidation reduction), and the down-regulated genes are belonged to ten molecular functions, nineteen biological process, but no cellular component. Significantly, the gene ontology analysis of the microarray data strongly suggests that the up-regulated retroelements transcripts and oxidoreductase activity genes, down-regulated recombinases, many down-regulated transcription factors involve in the response to the ion beam implantation for their expression changes. This gene ontology analysis might help to reveal the low-energy ion implantation regulation on many biological processes and metabolism pathways.