Background and purpose: Current colorectal cancer patient-derived xenografts (PDXs) models were established by samples taken during surgery. However, metastatic colorectal cancer (mCRC) patients have less surgical opportunities, and it was difcult to obtain enough tumor fragment. The aim of the present study was to es-tablish mCRC PDXs by image-guided biopsy. Methods: A total of 12 patients with colorectal cancer who underwent surgery were included. All patients had recurrent lesions or metastatic lesions needed to be histologically confirmed, and none of them had contraindication to biopsy. Tumor tissues not required for clinical diagnosis were used to establish mCRC PDXs. Results: Seven PDXs grew sufficiently for transfer into mice. The success rate was 77.8%. Conclusion:The PDXs established by image-guided biopsy had the advantage of convenient operation, good reproducibility, high achievement ratio, short experimental periodicity and reliably retain specific genetic and morphological features of the primary patient tumors.

Objective:To establish a multilocus sequence typing (MLST) assay for Corynebacterium ( C.) striatum, explore the population structure and evolution relationship of clinical isolates of C. striatum. Methods:Seven housekeeping genes ( gyrA, gyrB, hsp65, sodA, secA1, rpoB, 16S rRNA) were amplified with PCR by using self-designed specific primers and sequenced. Then, the sequences were assembled with software SeqMan. The gene diversity and gene recombination characteristics were evaluated by using software DnaSP 5.10.01 and Splits tree 4.14.2. The phylogenetic tree and the minimum spanning tree were constructed based on the sequence types (ST) characteristics by using software MEGA 7.0.14 and BioNumerics, respectively. In addition, the genetic evolutionary relationship among STs were analyzed by using software eBURST 3.0. Results:The expected amplification products of seven sites selected in all the test strains were obtained. Splits tree showed that the clustering of all C. striatum strains was consistent, suggesting that gene recombination is the potential driving force for the evolution of C. striatum. All of the 344 C.striatum strains were divided into 72 STs by MLST and 85.7% of the strains formed clonal complexes. CC19 was the predominant clonal complex, whereas ST16 in the clonal complex was detected in the most strains. ST had a certain geographic clustering and a certain correlation with the isolation time. Conclusions:C. striatum showed high genetic diversity in China and CC19 was the predominant clonal complex. The MLST assay established in this study can be used for the typing of C. striatum, but further improvement is needed.

Curcuminoids are rare diketone compounds in plants and can be found in the rhizome of Curcuma longa as well as other Zingiberaceae and Araceae. Curcuminoids have been widely used in food and medical area owing to the yellow colors, as well as the antioxidant and many other pharmacological activities. Curcuminoids are a mixture of compounds containing curcumin, demethoxycurcumin and bisdemethoxycurcumin, which have distinct benzene ring substituents. Currently, curcuminoids are exclusively produced through plant extraction, which do not satisfy the meeting of the market demand. Empowered with new synthetic biology tools and metabolic engineering strategies, there is renewed interest in production of curcuminoids using microorganisms. Heterologous production of curcuminoids has been achieved using Escherichia coli, Yarrowia lipolytica, Pseudomonas putida and Aspergillus oryzae via engineering of curcuminoids biosynthesis pathway. In this review, we first describe the biological activities and various applications of curcuminoids. Next, we summarize the biosynthetic pathway of curcuminoids in Curcuma longa and discuss the catalytic mechanisms of curcumin synthases. Then, we thoroughly explore recent advances in the use of distinct microorganisms for the production of curcuminoids with a special focus on metabolic engineering strategies. Finally, we prospect the microbial production of curcuminoids by highlighting some promising techniques and approaches.
Antioxidants ; Biosynthetic Pathways/genetics* ; Curcumin ; Diarylheptanoids ; Metabolic Engineering ; Plant Extracts