In 2010, the artificial synthesis of Mycoplasma mycoides triggers the new era of synthetic biology. This great breakthrough is achieved mainly thanks to the powerful DNA recombinant ability of yeast. In recent years, except for the methods used for large DNA assembly on the basis of in vivo homologous recombination, various different DNA assembly methods in vitro, based on the concept of DNA ligation or polymerization, have also been developed, such as Biobrick\BglBrick, SLIC and Gibson one-step assembly. Application of these new technologies has greatly accelerated the construction of synthetic part libraries, biosynthetic pathway and even microbial chromosomes. In fact, all DNA assembly methods are derived from the combinations of DNA joining and organizational schemes. This review describes the brief introduction of the main in vivo and in vitro DNA assembly protocols developed so for, which will benefit the construction of different types of synthetic functional devices and also biosynthetic pathways in the research of synthetic biology in China.
DNA ; biosynthesis ; chemistry ; genetics ; DNA, Recombinant ; biosynthesis ; genetics ; Genetic Engineering ; methods ; Metabolic Networks and Pathways ; Synthetic Biology ; methods

[Objective]To improve the preparative method of catilage derived microcarrier and evaluate the micromechanism and biocompatibility of this metarial for injectable tissue engineering cartilage.[Methods]Fresh porcine articular cartilage were obtained and shattered in the iso-osmia liquid in 4℃.After gradient centrifugation,150-300 ?m size cartilage micelles were gathered and were subjected to 1% Triton X-100 once and physiological saline twicely.The structure of specimens were observed and assessed by inverted phase contrast microscopy,environmental scanning electron microscope.And the composition of these specimens were stained with haematoxylin-eosin,safranin-O,toluidine blue and immunohistochemistry of collagen type Ⅱ.The microcarriers were seeded with rabbit bone mesenchymal stem cells(BMSCs) and cocultured with Rotary Cell Culture System(Rotary Cell Culture System,RCCS TM).[Results]The cartilage particles had fiocculus apparence.There were numerous villus on the surface of these cartilage micelles,which were stained positive with the immunohistochemistry of collagen type Ⅱ.The inner part of these cartilage micelles were stained positively with safranin-O and toluidine blue.After coated with BMSCs and cultured in the RCCSTM,the cells grew well on the surface of the cartilage micelles and the latter could be disperse again after blowed with pipette.[Conclusion]The cartilage micelles,which have large surface area and good boicompatibility,is a new kind of microcarrier for injectable tissue engineering cartilage.

Objective To investigate the effect of tumor necrosis factor receptor 1 (TNFR1) in angiogenesis and neurogenesis during cerebral ischemia in mice.Methods Twenty-four wild-type and 24 TNFR1 knockout mice were randomly divided into either a sham operation group or a focal cerebral ischemia group (n =12 in each group).5-bromodeoxyuridine (BrdU) was injected intraperitoneally at day 3 after cerebral ischemia and sham operation.At day 7 and 28 after cerebral ischemia,the double-label immunofluorescence staining of glucose transporter-1(Glut-1)/BrdU was used to evaluate the angiogenesis surrounding the areas of infarction.A labeled BrdU was used to detect the neural stem cell proliferation in the subventricular zone.Double-labeled doublecortin (DCX)/BrdU and neuronal nuclei antigen (NeuN)/BrdU were used to detect the migration and survival of neural stem cells,respectively.Results Under the normal condition,there was no significant difference in angiogenesis and the number of BrdU-positive cells in the subependymal zone (SVZ) between the wild-type (418.000 ± 28.404) and TNFR1 knockout (528.000 ± 60.597) mice (t =-1.644,P =0.131).At day 7 after cerebral ischemia,the number of Glut-1/BrdU-positive cells in the TNFR1 knockout mice was significantly less than that in the wild-type mice (14.833 ± 2.182 vs.27.5 ± 4.209) (t =2.672,P =0.023),and the number of DCX/B3rdU-positive cells was also significantly less than that in the wild-type mice (163.000 ± 11.106 vs.257.168 ± 12.213) (t =5.705,P =0.000).At day 28 after cerebral ischemia,the number of NeuN/BrdU-positive cells in the TNFR1 knockout mice was significantly less than that in the wildtype mice (6.000 ± 0.577 vs.11.000± 1.571) (t=2.988,P=0.014).Conclusions TNFR1 may play a promoting role in the neurovascular reggeneration in late cerebral ischemia.

Objective To study the expression of RUNX3 mRNA in primary liver cancer (PHC) tissue and its surrounding normal tissue,and its clinical significance.MethodsReverse transcription polymerase chain reaction (RT-PCR) was performed to detect the expression of RUNX3 mRNA in tumor and peritumor tissues in 51 patients with PHC.The relationship between RUNX3 mRNA expression and some clinical pathological parameters was analyzed.ResultsThe relative expression values of RUNX3 mRNA in the tumor tissue and the surrounding normal tissue were 0.4509±0.0963 and 0.9147± 0.0222,respectively.The difference was significant (t=33.6087,P＜0.001).The RUNX3 mRNA expression in tumor tissue correlated with some clinical pathological parameters including low tumor differentiation,positive cancer embolus and intrahepatic invasion and metastasis.The RUNX3 mRNA expression was not correlated with other clinicopathological parameters including gender,cancer diameter,cancer location,hemorrhage and necrosis of cancer,and histotype.ConclusionRUNX3 may be a new tumor suppressor gene for PHC.

Objective To study the fibrous capsule structure and its change after expansion.Methods Twelve minipigs were chosen for establishing the animal models of conventional intermittent tissue expansion (CITE) and continuous pressure tissue expansion (CPTE). The capsule samples were taken for measurement and histological examination.Results The thickness and the contraction rates of capsules in CPTE group were significantly less than those of CITE group. The capsule consisted of four layers, in which a large amount of collagen and elastic fibers existed and some small arteries, veins and capillaries were well developed. After expanded flaps were transplanted, capsules contained in flaps were partially degenerated except elastic fiber layer and fibrolaminar layer, but capsules on the wound bed almost all degenerated. Conclusion The results suggest that capsules have contractive and blood supply abilities. Capsulectomy is able to decrease flap contraction. Large expanded flaps are better to have the capsule reserved. No efforts shall be done to the capsules on wound beds.

Objective To investigate the cell dynamic changes of conventional intermittent tissue expansion (CITE) and continuous pressure controlled tissue expansion (CPTE). Methods Domestic pigs were chosen for CITE and CPTE models. Immunohistochemical technique was used to detect proliferative cells, DNA fragments in situ labeling for apoptotic cells, and H E stain for total fibroblast counting. Results Proliferative index of basal cell increased during expansion. The peak value of 78.5% reached at the ninth day in the CITE group versus 84.2 % at fourth day in the CPTE group. Proliferation index in both groups decreased after expansion. Fibroblast proliferation, apoptosis and total fibroblast density increased slowly in both groups during and after expansion. At the sixth day, total fibroblast densities in CITE group (38.1 cells/H) and in CPTE group (40.9 cells/H) were significantly increased, compared with 34.93 cells/H in the normal skin. There were obvious proliferation and apoptosis phenomena in epidermal cells and skin adnexa. Conclusion Tissue expansion has both effects of proliferation and apoptosis on cell dynamics. Continuous tissue expansion can induce tissues growing much effectively.

OBJECTIVE:To investigate the perioperative prophylactic use of antibacteirals in patients undergoing simple goiter surgery.METHODS:The perioperative prophylactic use of antibacteirals in 240 patients of our hospital undergoing simple goiter surgery was analyzed statistically in respect of drug variety,DDDs,drug combination,medication time,curative effects,adverse drug reactions(ADR)etc.RESULTS:Of the 240 cases,238(99%)received prophylactic antimicrobials,with cephalosporins and quinolones dominating the list in terms of DDDs.The irrational drug use manifested as high proportion of high grade drugs in preventive medication,the prolonged postoperative use of antibacterials,and high rate of combined use of drugs etc.CONCLUSION:It is urgent to intensify physicians' consciousness about rational perioperative use of antibacterials.

Objective To explore measures for the reform of the cooperative business operation system of township public health centers and evaluate in a comprehensive way the results of the reform. Methods A study was made by means of typical investigation of the specific measures taken by 16 township public health centers in Xianju County of Zhejiang Province in the reform of the cooperative business operation system and changes in health resources and service efficiency brought about by the reform were analyzed. Results In the reform, mixed type cooperation was adopted, with public ownership dominating; current assets were assigned in the form of stocks, with all the staff having a share; and a distribution system was established, clarifying the proportions of state, collective and personal interests. As a result, the infrastructures of the centers were enhanced, the service capabilities improved, the financial situation bettered, the value of national assets increased, the potentialities of the staff brought into full play, and social benefits maximized. Conclusion The measures taken by the centers in the reform, which were basically sound and resulted in significant first fruits, could be popularized as an effective model for deepening the reform of health care institutions in the rural areas.

Objective To analyze the impact of health service and some other factors on the improvement of health. Methods The production function model introduced by Auster was employed. With the age adjusted mortality taken to be the output of health and factors like health service, life style, living environment, economy, and education taken to be the input, the two-stage least square was used to analyze the impact as well as the degree of the impact of the various factors. Results The impact of health service, the contribution of which to the age adjusted mortality was around 0.37, was greater than that of education but smaller than that of economy. Conclusion The result indicates that health service is an important influencing factor in the improvement of health. Full attention ought to be paid to it so that investment into health, especially public health, will be expanded and the health of the people better protected.

2 months were selected. Anthropometric measurements, laboratory examinations and dietary surveys were used to assess the nutritional status. ResultsBody weight(53.714.6)kg and body mass index (BMI) (19.34.6)kg/m~2were in low normal range. Total lymphocyte counts (2.000.71)10~9/L and serum transferrin contents (1.800.44)g/L were decreased and the creatinine-height index (42.4321.82)% was obviously lower than normal range of adult. ConclusionsThese patients have energy deficiency. The changes of the mentioned parameters could be the reflection of the nutritional status of these patients and also closely related to the changes of their body composition. It is necessary to evaluate nutritional state of the elderly patients. However, the characteristics of the body composition of the elderly patients should not be ignored and a global assessment is needed.