Construction of synthetic promoters for Escherichia coli and application in the biosynthesis of cis,cis-muconic acid / 生物工程学报

Promoter is one of important elements for gene expression and regulation. In the construction of recombinants for metabolic engineering and synthetic biology, it is necessary to have the promoters with varying strengths for fine-tuning metabolic pathway to reach the metabolic balance, decrease the accumulation of intermediate and increase the production of target metabolite. However, the natural promoters available are not completely suitable for fine-tuning metabolic pathway due to discrete strength, lack of versatility and standardization. To deal with this problem, in this study, a new 88 bp synthetic promoter, which contains the typical -35 box, -10 box as well as ribosome bind site, was designed. Then, the promoter library was constructed by introducing some degenerate base pairs in the sequence of 6 bp in the upstream of the initial transcription site and 14 bp in spacer region between -35 and -10 box. 720 promoters with varying strengths were screened out from a library of more than 5 000 clones via the expression of red fluorescent protein mCherry under the control of the synthetic promoter. The sequence analysis based on 35 promoters with varying strengths showed the promoters with varying strengths are base preference. The purine bases in -13 site and pyrimidine bases in the transcriptional initiation sequence are of high frequency; the purine and pyrimidine bases are of the similar frequency in the spacer sequence between -35 and -10 box in strong promoter. In the end, five characterized promoters with varying strengths were selected to tune the synthetic pathway of cis,cis-muconic acid in Escherichia coli. The results showed that the promoters with varying strengths can regulate the production of cis,cis-muconic acid and the accumulation of the intermediate catechol.

Atticotomy with canaloplasty and tympanoplasty for limited epitympanic cholesteatoma / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To observe the surgical results of atticotomy with canalopalsty and tympanoplasty for limited cholesteatoma.@*METHOD@#Thirty-one cases of limited epitympanic cholesteatoma and retraction pocket received atticotomy. The surgical procedure consisted of eliminating cholesteatoma and pocket, reconstructing lateral epitympanic wall and tympanoplasty with cartilage/perichondrium island flap.@*RESULT@#The anatomic pattern of external ear canal appeared near normal, and the hearing level improved or remained normal during 2-year follow up except for 2 cases with tympanosclerosis. No epitympanic retraction pocket or cholesteatoma relapsed. 1 case appeared tympanic perforation.@*CONCLUSION@#Atticotomy, contemporaneous reconstruction of lateral epitympanic wall and tympanoplasty with cartilage/perichondrium, indicated to be a reliable treatment and prevention technique for epitympanic cholesteatoma. It can achieve good morphological and functional results.

The clinical analysis of cat scratch diseases with enlarged masses / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#In order to raise awareness of CSD and reduce misdiagnosis, we study the manisfection and treatment of CSD with enlarged masses.@*METHOD@#A retrospective study was carried out among the 10 identified patients with CSD on the basis of compatible clinical presentation and confirmatory pathology results for CSD.@*RESULT@#All the 10 patient's first symptoms were masses at some part of the body, more common in the neck. The ratio was 5% at neck, 3% at armpit, 1% at upper, 1% at groin. Two patients had low heat, increased leukocyte and larger masses of more than 2 cm in diameter After surgical resection, and anti-inflammatory treatment. All the patients were cured after surgery and postoperative anti-inflammatory treatment, and there was no recurrence during the 7-year follow-up.@*CONCLUSION@#If patients were diagnosed and treated timely, the prognosis will be good. For the cases with extremely enlarged lymphonodus, surgical operation followed by antimicrobial chemotherapy will be a effective treatment.

Research progress of bioactive titania film based on biological treatment by microarc oxidation / 医疗卫生装备

As a new surface technology, microarc oxidation can be applied to the ceramic coating with bioactivity on Ti alloy. With good biocompatibility, high bond strength and short healing period, the film is worth applying to clinical operation. In this paper such information of microarc oxidation is reviewed as its developing history, research progress and basic principle. The structure, properties and bioactivity of the ceramic coating are also introduced.