[Differentiation of Rhododendron based on the infrared spectra of petals].

Several techniques were used to identify and classify plants. Mid-infrared spectroscopy combined with appropriate software was used in an attempt to differentiate different subgenus from Rhododendron. Fourier transform infrared (FTIR) spectroscopy was used for obtaining vibrational spectra of 46 petals from Rhododendron. Very minor differences were observed in the FTIR spectra among four subgenuses. For the purpose of rapid differentiation, libraries of spectra were created using samples from each subgenus variety. Spectra of unknown samples were recorded and compared with those of the libraries and the rate of affinity (the match value) was measured automatically using the appropriate software (OMNIC). The results showed that petal samples from different subgenus varieties can be differentiated from each other. The study demonstrates that combining FTIR spectroscopy with appropriate analysis method can classify Rhododendron plants at subgenus level. It offers a potential method for the taxonomic research on plants system.

[Detecting int I 1 gene expression of Pseudomonas aeruginosa with fluorescent quantitative PCR assay].

OBJECTIVE: In order to understand the role of integron, fluorescent quantitative polymerase chain reaction (FQ-PCR)was developed to measure the changes in int I 1 gene expression of Pseudomonas Aeruginosa in biofilm and planktonic cells. METHODS: Three clinical strains of P. aeruginosa with int I 1 gene (SW07, R07 and TH12) were cultured in planktonic cells and biofilm cells. The total RNA of these cultured bacteria were extracted by the conventional method. The FQ-PCR was developed to measure the changes in int I 1 mRNA expression of the P. aeruginosa with bacterial 16s rRNA as an internal control. RESULTS: The three clinical strains of P. aeruginosa expressed int I 1 mRNA in both biofilm and planktonic cells, but with different levels. The int 1 mRNA expressed by the RO7, SW07 and TH12 strains in the biofilm cells were 1.4, 5.7 and 128 times higher than in the planktonic cells, respectively. CONCLUSION: The int I 1 gene expression of P. aeruginosa in the biofilm is up-regulated at mRNA level. The integron may capture and accumulate drug resistance gene cassettes more effectively in the biofilm condition.