Corrosion resistance and antibacterial activity of zinc-loaded montmorillonite coatings on biodegradable magnesium alloy AZ31.

A Zinc-loaded montmorillonite (Zn-MMT) coating was hydrothermally prepared using Zn2+ ion intercalated sodium montmorillonite (Na-MMT) upon magnesium (Mg) alloy AZ31 as bone repairing materials. Biodegradation rate of the Mg-based materials was studied via potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and hydrogen evolution tests. Results revealed that both Na-MMT and Zn-MMT coatings exhibited better corrosion resistance in Dulbecco's modified eagle medium (DMEM) + 10% calf serum (CS) than bare Mg alloy AZ31 counterparts. Hemolysis results demonstrated that hemocompatibility of the Na-MMT and Zn-MMT coatings were 5%, and lower than that of uncoated Mg alloy AZ31 pieces. In vitro MTT tests and live-dead stain of osteoblast cells (MC3T3-E1) indicated a significant improvement in cytocompatibility of both Na-MMT and Zn-MMT coatings. Antibacterial properties of two representative bacterial strains associated with device-related infection, i.e. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), were employed to explore the antibacterial behavior of the coatings. The measured inhibitory zone and bacterial growth rate confirmed that Zn-MMT coatings exhibited higher suppression toward both E. coli and S. aureus than that of Na-MMT coatings. The investigation on antibacterial mechanism through scanning electron microscopy (SEM) and lactate dehydrogenase (LDH) release assay manifested that Zn-MMT coating led to severe breakage of bacterial membrane of E. coli and S. aureus, which resulted in a release of cytoplasmic materials from the bacterial cells. In addition, the good inhibition of Zn-MMT coatings against E. coli and S. aureus might be attributed to the slow but sustainable release of Zn2+ ions (up to 144 h) from the coatings into the culture media. This study provides a novel coating strategy for manufacturing biodegradable Mg alloys with good corrosion resistance, biocompatibility and antibacterial activity for future orthopedic applications. STATEMENT OF SIGNIFICANCE: The significance of the current work is to develop a corrosion-resistant and antibacterial Zn-MMT coating on magnesium alloy AZ31 through a hydrothermal method. The Zn-MMT coating on magnesium alloy AZ31 shows better corrosion resistance, biocompatibility and excellent antibacterial ability than magnesium alloy AZ31. This study provides a novel coating on Mg alloys for future orthopedic applications.

Modern biotechnology in China.

In recent years, with the booming economy, the Chinese government has increased its financial input to biotechnology research, which has led to remarkable achievements by China in modern biotechnology. As one of the key parts of modern biotechnology, industrial biotechnology will be crucial for China's sustainable development in this century. This review presents an overview of Chinese industrial biotechnology in last 10 years. Modern biotechnology had been classified into metabolic engineering and systems biology framework. Metabolic engineering is a field of broad fundamental and practical concept so we integrated the related technology achievements into the real practices of many metabolic engineering cases, such as biobased products production, environmental control and others. Now metabolic engineering is developing towards the systems level. Chinese researchers have also embraced this concept and have contributed invaluable things in genomics, transcriptomics, proteomics and related bioinformatics. A series of advanced laboratories or centers were established which will represent Chinese modern biotechnology development in the near future. At the end of this review, metabolic network research advances have also been mentioned.

[The research progress of succinic acid fermentation strains].

The potential of succinic acid as an important chemical intermediates had been realized and fermentation is one of the best ways to make it possible in economical aspect. Fermentation organism is the key part of the fermentation method. The updated research developments of fermentation organisms and the fermentation characteristics and problems of them were reviewed and analyzed in this paper. Finally,the development future of fermenation organism was forecasted.

Integrating metabolomics into a systems biology framework to exploit metabolic complexity: strategies and applications in microorganisms.

As an important functional genomic tool, metabolomics has been illustrated in detail in recent years, especially in plant science. However, the microbial category also has the potential to benefit from integration of metabolomics into system frameworks. In this article, we first examine the concepts and brief history of metabolomics. Next, we summarize metabolomic research processes and analytical platforms in strain improvements. The application cases of metabolomics in microorganisms answer what the metabolomics can do in strain improvements. The position of metabolomics in this systems biology framework and the real cases of integrating metabolomics into a system framework to explore the microbial metabolic complexity are also illustrated in this paper.

[Correlation of FHIT expression to cell proliferation and metastasis of laryngeal squamous cell carcinoma].

BACKGROUND & OBJECTIVE: Fragile histidine triad (FHIT) gene, a candidate tumor suppressor gene, located at 3pl4.2, spans the most common fragile site, FRA3B, in human genomes. It is altered in many human cancers, such as head and neck squamous cell carcinoma. This study was to investigate correlation of FHIT expression to cell proliferation and metastasis of laryngeal squamous cell carcinoma (LSCC). METHODS: Expression of FHIT protein, and proliferating cell nuclear antigen (PCNA) was detected by SP immunohistochemistry in 41 specimens of LSCC and their matched adjacent non-cancerous epithelium (NCE). RESULTS: Positive rates of FHIT in NCE, and LSCC were 100.0% (41/41), and 46.3% (19/41) (P< 0.01); in LSCC of stage I-II, and stage III-IV were 69.6% (16/23), and 16.7% (3/18) (P< 0.01); in lymph node metastasis group, and no metastasis group were 20.0% (3/15), and 61.5% (16/26) (P< 0.05). PCNA labeling indexes in NCE, and LSCC were (9.98+/-2.34)%, and (50.71+/-13.64)% (P< 0.01). In LSCC, expression of FHIT negatively correlated with PCNA (P< 0.05). CONCLUSION: Low expression of FHIT might play an important role in cell proliferation and metastasis of LSCC, FHIT might be a useful marker for evaluating biological behaviors of LSCC.