Promoter detection and transcriptional analysis of the spinosad biosynthetic gene cluster / 生物工程学报

Spinosad represents a new class of insecticides produced by Saccharopolyspora spinosa. To understand the transcription of the spinosad biosynthetic gene cluster, two promoter detection plasmids based on different reporter genes were constructed and used to detect 9 promoters in the spinosad biosynthetic gene cluster. In addition, the temporal transcriptional profiles of the corresponding genes controlled by the 9 promoters, together with 4 genes outside of the spinosad cluster but are required for the synthesis of sugars in spinosad, were examined by real-time PCR. The results indicate that the 9 spinosad biosynthetic genes were highly expressed at the stationary phase, which coincides with the accumulation of spinosad in the fermentation broth. Of particular note is that the transcription of the 4 sugar synthetic genes showed higher level at the exponential phase, suggesting the expression of sugar synthetic genes is not correlated with the spinosad synthetic genes. The data suggest that spinosad biosynthesis could be improved by engineering the expression pattern of the sugar synthetic genes that lie outside the spinosad gene cluster.

Study on the normal testis in puberty by color Doppler ultrasonography / 西安交通大学学报(医学版)

Objective To study the anatomy and homodynamics of the normal testis vessels in puberty using color Doppler flow imaging to obtain the normal value ranges of each flow parameter and evaluate the waveform characteristics of the testicular and its clinical significances. Methods The anatomy and homodynamic parameters of testicular artery (TA), capsular artery (CA), intratesticular artery (ITA), deferential and cremasteric arteries were studied in 141 normal pubertal volunteers. The following blood flow parameters were included: time average maximum velocity (TAMX), peak systolic velocity (PSV), end diastolic velocity (EDV), pulsatility index (PI) and resistance index (RI). Results ① The blood flow in TA, CA and ITA was visualized bilaterally in all the subjects; deferential and cremasteric arteries were identified in 98.6% of the subjects. ② The normal ranges of the homodynamic parameters of supratesticular artery, CA and ITA were obtained in puberty. ③ PSV, PI and RI decreased gradually in the following arteries: TA→CA→ITA. Conclusion The testicular arterial anatomy and arterial waveform characteristics of normal pubertal testis can be accurately evaluated by CDFI. It is helpful for the diagnosis and differential diagnosis of testicular diseases in pubertal youngsters.