Current molecular biologic techniques for characterizing environmental microbial community

Microbes are vital to the earth because of their enormous numbers and instinct function maintaining the natural balance. Since the microbiology was applied in environmental science and engineering more than a century ago, researchers desire for more and more information concerning the microbial spatio-temporal variations in almost every fields from contaminated soil to wastewater treatment plant （WWTP）. For the past 30 years, molecular biologic techniques explored for environ- mental microbial community （EMC） have spanned a broad range of approaches to facilitate the researches with the assistance of computer science： faster, more accurate and more sensitive. In this feature article, we outlined several current and emerging molecular biologic techniques applied in detection of EMC, and presented and assessed in detail the application of three promising tools.

Biocompatibility evaluation in vitro. Part III: Cytotoxicity expression of human and animal osteoblasts on the biomaterials

Exclusion and inflammation in the clinic are observe d for various reas ons including material che- mical composition, physical properties as well a s macr o- and micro-structure of the implants, surface condition of the implants, and also patient dependent factors. Cytotoxicity expression of cells is a central issue i n current biocompatibility to screen the potential implant materials and drugs. This study was aimed at investigation reaction between the potential implant mat erials and surround tissue. Cytotoxicity of human and rat osteoblast in the mate rial extracts was determinated by testing standards such as GHS assay, MTT assay , alkaline phosphatase activity assay, LDH assay, and Lowry assay. Research resu lts demonstrated that compared with the control condition polystyrene culture pl a te both human and rat osteoblast cells have normal phenotypic expression in hydr oxyapatite extract, and this expression was statistically restricted in hydroxya patite-spinel extract. How- ever, this restrict, e.g. cytotoxicity could be partially eliminated by immersion treatment of the materials in culture medium.

Influences and mechanisms of nanofullerene on the horizontal transfer of plasmid-encoded antibiotic resistance genes between E.coli strains

The spread and development of antibiotic resistance globally have led to severe public health problems.It has been shown that some non-antibiotic substances can also promote the diffusion and spread of antibiotic resistance genes(ARGs).Nanofullerene(nC60)is a type of nanomaterial widely used around the world,and some studies have discovered both the biological toxicity and environmental toxicity of nC6O .In this study,cellular and molecular biology techniques were employed to investigate the influences of nC6O at sub-minimum inhibitory concentrations(sub-MICs)on the conjugation of ARGs between the E.coli strains.Compared with the control group,nC6O significantly increased the conjugation rates of ARGs by 1.32-10.82 folds within the concentration range of 7.03-1800μg/L.This study further explored the mechanism of this phenomenon,finding that sub-MICs of nC6O could induce the production of reactive oxygen species(ROS),trigger SOSresponse and oxidative stress,affect the expression of outer membrane proteins(OMPs)genes,increase membrane permeability,and thus promote the occurrence of conjugation.This research enriches our understanding of the environmental toxicity of nC6O,raises our risk awareness toward nC6O ,and may promote the more rational employment of nC6O materials.