Microbial genome reduction and modification are important strategies for constructing cellular chassis used for synthetic biology. This article summarized the essential genes and the methods to identify them in microorganisms, compared various strategies for microbial genome reduction, and analyzed the characteristics of some microorganisms with the minimized genome. This review shows the important role of genome reduction in constructing cellular chassis.
Genes, Essential ; genetics ; Genetic Engineering ; Genome, Microbial ; genetics ; Synthetic Biology ; methods

Objective:To study the relationship between the expression of Fas,Fas Ligand and epidermal tumors' malignant degree.Methods:The immunohistochemical technique was employed to detect the expression of Fas and Fas Ligand in Bowens' disease,Squamous Cell Carcinoma(SCC)and Basal Cell Carcinoma(BCC).Results:The Fas and Fas Ligand could be detected in Bowens disease and SCC.The intensity of expression of Fas was downregulated and that of Fas Ligand was upregulated along with the maligant degree increasing of tumors.The expression of Fas,Fasl in BCC were lower than that in Bowens disease and SCC.Conclusion:The expression of Fas and Fas Ligand were correlated to malignant degree and clinical prognosis of some epidermal tumors,for abnormal apoptosis directed by contract of Fas and Fas Ligand may be one of the causes responsible to epidermal tumor's local immune escaping.

Objective To evaluate the hot and cold characteristics of 10 antibiotics.Methods MTT assay was used to investigate the effects of 10 antibiotics on the growth and proliferation of cultured SMMC7721 cells and MFC-7 cells in vitro .Morphological changes were observed under the inverted microscope.Results The 10 antibiotics,namely,ampicillin,cefixime,cefpodoxime proxetil,cefaclor,cefalexin,azithromycin,clarithromycin, roxithromycin,doxycycline and oxytetracycline showed cold or cool characteristics.Morphological observation showed that cells treated with these drugs presented decreased cell density and turned round.Conclusion The results of this study demonstrated that the cytological method can be used to evaluate the hot and cold characteristics of western drugs.This simple and reliable method will promote research on Chinese medicalization of western drugs.

ObjectiveTo identify the relevant factors of expansion of contusive cerebral hemorrhage following unilateral decompressive craniectomy in patients with severe craniocerebral injury and discuss their relation with prognosis.MethodsA total of 161 consecutive patients with craniocerebral injury undergoing unilateral decompressive craniectomy were prospectively studied.Their initial cranial CT data (data after injury,data before operation,and data after first operation) were recorded.Mortality or Glasgow Outcome Scale (GOS) at 6 months after injury was used as the criteria for evaluation of prognosis.ResultsThe volume of increased contusive cerebral hemorrhage among the patients after craniectomy was (18.66 ± 22.69) ml.The Rotterdam score of their initial cranial CT after injury was significantly associated with the occurrence or not of expanded contusive cerebral hemorrhage following decompressive craniectomy and the expanded hematoma volume.The expanded volume of contusive cerebral hemorrhage ( ＞ 20 ml) after craniectomy showed significant relevance to mortality and poor prognosis six months later.The magnitude of external cerebral herniation ( ECH ) on the initial post-operative CT was associated with the prognosis. ConclusionsThe severity of patients with craniocerebral injury manifested by the initial cranial CT may predict the risk of expansion of contusive cerebral hemorrhage following decompressive craniectomy.The expansion volume of contusive cerebral hemorrhage and ECH are correlated with mortality and poor prognosis.

The expression of proliferating cell nuclear antigen (PCNA) was studied in 50 cases of squamous cell carcinoma of the skin using immunohistochemistry and PCNA cyclin monoclonal antibody. PCNA staining was found in the nuclei of tumour cells, two types of staining were seen, a granular pattern and a more diffuse nuclear staining. The expression of PCNA showed a significant positive correlation with degrees of differentiation of the carcinoma cells and lymph node metastasis (P

The expressions of p53 protein, PCNA and macrophage count in 50 cases of skin squamous cell carcinoma were studied by LSAB immunostaining of monoclonal antibodies (PC-10, CD68 and Do-7). The relationship between the proliferation of cancer cell and the count of stroma macrophage to the degree of differentiation was studied and observed in situ. The results showed that the positive rates of expression of both p53 protein and PCNA in the squamous cell carcinoma were 56% and 100%, respectively. The distribution and strength of the expression of p53 protein and PCNA were positively correlated to the degree of cell differentiation. Macrophoge regularly located in the margin of cancer nest. The macrophage count was reversely correlated to the degree of differentiation. It is concluded that the degree of differentiation is parallel to the expression of p53 protein and PCNA, whereas, the macrophages in the stroma to some extent inhibits the cancer cell proliferation.

Objective To study and solve the reconstruction of the defects of first metatarsal and the forefoot. Methods Using microsurgical technique,adopt transplantation of vascularized iliac bone incorporating with free flap to restore the defects of first and second metatarsal as well as forefoot. Results The injuried foot was restored its weight-bearing and walking functions and obtained a satisfactory contour. Conclusion The vascular iliac bone was an ideal donor site for reconstruction of absense of metatarsal,and vascular bone incorporating free flap were proved superiorly in treatment of forefoot defects.

Objective To investigate the expression of matrix metalloproteinases(MMP) related to oncogene C-myc and tumor differentiation of cutaneous squamous cell carcinoma (CSCC). Methods Expression of MMP2,MMP9 and C-myc was detected by immunohistochemistry in 68 paraffin embedded specimens of CSCC. Results Distribution of MMP2 and MMP9 was demonstrated within cytoplasm of tumor and stromal cells, especially for those cells at the interface of tumor and interstitial tissues. No expression of MMP2 and MMP9 was observed in the horny centers of tumor cell nests. Expression of MMP2 and MMP9 increased along with the decreasing of the differentiation of tumor tissue and the increasing of C-myc expression. Conclusions Expression of MMP2 and MMP9 might be a common event for both tumor and stromal cells but parenchymal tumor cells might predominate over the activation of MMP2 and MMP9. Oncogene C-myc protein might promote the secretion of MMP2 and MMP9 by tumor cells.

A series of paeonol derivatives have been synthesized by simple acylation and etherification of the paeonol. Anti-tumor activities of the synthesized compounds were evaluated against HeLa and MCF-7 cells lines in vitro by the standard MTT assay. It was found that the derivatives were more active against HeLa than MCF-7. The results also indicated that 4-methoxy group is the synergistic group of paeonol's anti-tumor activity and ketone carbonyl side chain is essential functional group of paeonol's anti-tumor activity. Compound 2d had stronger antiproliferative activities than paeonol against HeLa and MCF-7 cell lines with IC50 values of 2.67 and 4.74 micromol x L(-1) respectively. The results showed that paeonol derivatives were worth to be intensively studied further.

Objective To study and discuss the problems involved in as well as the significance a nd methods of restoration and reconstr uction of forefoot defects.Methods Various procedures were adopted ac-cording to the wound variety and severity.For just absense of mefatarsal bones,only soft tissue was restored.For defects of metatarsals or metatarso phalangeal joints(usually associated with soft tissue defects)homochronous reconstruction and restoration was conducted by using vascularized bon e incorporation with free flap transplan-tation.Results Total 47cases wih forefoot defects were recpaired by using procedures me ntioned above from1994to 2000.All of this group regain ed their walking and weight-bearing functions as well as a good appearance.Conclusions Classification of forefoot injurie s according to their severity and loc ation is helpful in treatment,precise description and further stu dy of the injuries.Vascular bone incorporating with vascular flaps proved to be an ideal method of repairing compound defects.