Seamless site-directed mutagenesis in complex cloned DNA sequences using the RedEx method.

Seamless site-directed mutagenesis is an important technique for studying protein functions, tuning enzyme catalytic activities and modifying genetic elements in multiple rounds because it can insert, delete or substitute nucleotides, DNA segments or even entire genes at the target site without introducing any unwanted change. To facilitate seamless site-directed mutagenesis in large plasmids and bacterial artificial chromosomes (BACs) with repetitive sequences, we recently developed the RedEx strategy. Compared with previous methods, our approach achieves the recovery of correct recombinants with high accuracy by circumventing unwanted recombination between repetitive sequences.

Development of a bacterial gene transcription activating strategy based on transcriptional activator positive feedback.

Introduction: Transcription of biological nitrogen fixation (nif) genes is activated by the NifA protein which recognizes specific activating sequences upstream of σ-dependent nif promoters. The large quantities of nitrogenase which can make up 20% of the total proteins in the cell indicates high transcription activating efficiency of NifA and high transcription level of nifHDK nitrogenase genes.

Objectives: Development of an efficient gene transcription activating strategy in bacteria based on positive transcription regulatory proteins and their regulating DNA sequences.

Precise genome engineering in Pseudomonas using phage-encoded homologous recombination and the Cascade-Cas3 system.

A lack of generic and effective genetic manipulation methods for Pseudomonas has restricted fundamental research and utilization of this genus for biotechnology applications. Phage-encoded homologous recombination (PEHR) is an efficient tool for bacterial genome engineering. This PEHR system is based on a lambda Red-like operon (BAS) from Pseudomonas aeruginosa phage Ab31 and a Rac bacteriophage RecET-like operon (Rec-TE) from P.

Establishing an efficient salinomycin biosynthetic pathway in three heterologous Streptomyces hosts by constructing a 106-kb multioperon artificial gene cluster.

Salinomycin is a promising anticancer drug for chemotherapy. A highly productive biosynthetic gene cluster will facilitate the creation of analogs with improved therapeutic activity and reduced side effects. In this study, we engineered an artificial 106-kb salinomycin gene cluster and achieved efficient heterologous expression in three hosts: Streptomyces coelicolor CH999, S.

RedEx: a method for seamless DNA insertion and deletion in large multimodular polyketide synthase gene clusters.

Biosynthesis reprograming is an important way to diversify chemical structures. The large repetitive DNA sequences existing in polyketide synthase genes make seamless DNA manipulation of the polyketide biosynthetic gene clusters extremely challenging. In this study, to replace the ethyl group attached to the C-21 of the macrolide insecticide spinosad with a butenyl group by refactoring the 79-kb gene cluster, we developed a RedEx method by combining Redαβ mediated linear-circular homologous recombination, ccdB counterselection and exonuclease mediated in vitro annealing to insert an exogenous extension module in the polyketide synthase gene without any extra sequence.

Single-Stranded DNA-Binding Protein and Exogenous RecBCD Inhibitors Enhance Phage-Derived Homologous Recombination in Pseudomonas.

The limited efficiency of the available tools for genetic manipulation of Pseudomonas limits fundamental research and utilization of this genus. We explored the properties of a lambda Red-like operon (BAS) from Pseudomonas aeruginosa phage Ab31 and a Rac bacteriophage RecET-like operon (RecTE) from Pseudomonas syringae pv. syringae B728a.

[Influence of leukoaraiosis on the cognition of patients with Parkinson disease].

Objective: To explore the role of leukoaraiosis (LA) on the cognitive function in patients with Parkinson disease (PD).

Methods: The cohort for this study included 63 patients with PD, whom were divided into 3 groups according to cognitive status:with intact cognition (PD-IC, n = 23), with mild cognitive impairment (PD-MCI, n = 23) and with dementia (PDD, n = 17). All the patients were recruited from the Department of Neurology, First Affiliated Hospital, Anhui Medical University between September 2011 and July 2012.

The role of different therapeutic courses in treating 47 cases of rheumatoid arthritis with acupuncture.

Objective: To observe the effect of acupuncture therapeutic courses on rheumatoid arthritis.

Method: Forty-seven patients were treated with acupuncture for 6 courses and at the end of the third and sixth course of treatment, the therapeutic effects of acupuncture on morning rigidity, swelling and pain of joints as well as rheumatoid factor (RF), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were observed.

Result: At the end of the third course, the markedly effective rate was 34.