Chunxia Zhang

Graphene oxide-DNA based sensors.

Since graphene oxide (GO) is readily available and exhibits exceptional optical, electrical, mechanical and chemical properties, it has attracted increasing interests for use in GO-DNA based sensors. This paper reviews the advances in GO-DNA based sensors using DNA as recognition elements. In solution, GO is as an excellent acceptor of fluorescence resonance energy transfer (FRET) to quench the fluorescence in dye labeled DNA sequences. This review discusses the emerging GO-DNA based sensors related to FRET for use in the detection of DNA, proteins, metal ions, cysteine (Cys), and others. The application of the electrochemical GO-DNA based sensors is also summarized because GO possesses exceptional electrochemical properties. The detection mechanisms and the advantages of GO are also revealed and discussed. GO-DNA based sensors perform well at low cost, and high sensitivity, and provide low detection limits. Additionally, GO-DNA based sensors should appear in the near future as scientists explore their usefulness and properties. Finally, future perspectives and possible challenges in this area are outlined.

The toxicity of NaF on BmN cells and a comparative proteomics approach to identify protein expression changes in cells under NaF-stress: impact of NaF on BmN cells.

Fluorides negatively affect the development of organisms and are a threat to human health and environmental safety. In this study, Bombyx mori N cell line (BmN) were used to explore effects of NaF on insect cells. We found that 8h (hrs) culture with high concentration of NaF (≥ 1 mM) induced significantly morphological changes. Dose-response curves of 72 h continuously cultured BmN treated with NaF showed that the half inhibitory concentration (IC50) value was 56.60 μM. Treatment of BmN with 100 and 300 μM of NaF induced apoptosis and necrosis. 2-D electrophoresis of whole cell extracted from BmN showed that treatment with 300 μM NaF up-regulated 32 proteins and down-regulated 11 proteins when compared with controls. We identified 5 different proteins by MALDI-TOF MS, and 4 of them were identified for the first time, including 2 up-regulated proteins (mitochondrial aldehyde dehydrogenase ALDH2 and prohibitin protein WPH) and 2 down-regulated proteins (calreticulin precursor CRT and DNA supercoiling factor SCF). These observations were further confirmed by fluorescence quantitative PCR. Together, our data suggest that these target proteins could be regarded as targets influenced by NaF and also provide clues for studies on the response metabolism pathway under NaF stress.

An investigation and evaluation on species and characteristics of pathogenic microorganisms in Chinese local hospital settings

There are currently great concerns about the level of bacterial contamination in hospitals, as well as resistance to antimicrobial agents. The species and characteristics of microbes in Chinese hospitals are closely related to healthcare safety and the prevention and control of infections. However, data on the exposure of patients to microbes in Chinese hospitals are limited. The present study investigated the genera of microorganisms in Chinese hospitals. We evaluated their characteristics, such as antibiotic susceptibility, tolerance to disinfectants, and toxicity, using silkworms (Bombyx mori) as an animal model. Twenty-six distinct bacterial strains were isolated, and their genera were determined by sequencing their 16S rDNA regions. Twenty-five strains were resistant to one or more antibiotics, and six strains were resistant to multiple antibiotics. The results of minimal inhibitory concentration testing showed that eight strains were resistant to a chlorine-containing disinfectant, and 12 strains were resistant to Povidone-iodine. Following the injection of bacterial cultures into the silkworm hemolymph, 15 strains killed all of the silkworms within 5 d. Additionally, bacterial strain 14 killed all of silkworms within 12 h with a median lethal dose of 4 × 10(4) colony-forming units/larva. This study provides useful information for healthcare safety in Chinese hospitals.

Biogenesis of Multivesicular Body and Protein Sorting: No One of ESCRT,Vps4 and Ubiquitination Can Be Missed

Multivesicular body(MVB) is a dynamic subcellular organelle formed by invagination of the limiting membrane of late endosome.MVB is an essential transport and sorting station for membranes and proteins in eukaryotic organisms.MVB pathway is intimately involved in various processes,including signal transduction,cytokinesis,gene silencing,autophagy,protein quality control and virus budding.The biogenesis of MVB requires more than 20 vacuolar protein sorting(Vps) proteins.Many of them can assemble into four distinct complexes ESCRT 0,Ⅰ,Ⅱ,Ⅲ(endosomal sorting complexs required for transport) on the endosomal membrane.ESCRTs and Vps4 are considered to be the most important components in MVB pathway.ESCRT 0 together with clathrin can form microdomain on endosomal membrane where they cluster ubiquitinated cargo proteins.ESCRTⅠ and Ⅱ can induce the budding of intraluminal vesicles(ILVs),prompt the formation process and sort protein cargoes into ILVs.ESCRTⅢ can constrict,cleave the bud neck and finish the membrane abscission,the last stage of MVB formation.Vps4 can disassemble ESCRT complexes and recycle them.Ubiquitinated cargo proteins and ubiquitination can also regulate the localization and function of ESCRTs.Together,these recent discoveries demonstrate that the sequential and co-ordinated actions of ubiquitinated cargo proteins,ESCRTs and Vps4 are the major driving force for the biogenesis of MVB and protein sorting process.In this review,we focus on the protein-protein interaction and mainly discuss the assembly mechanism,interaction and function of ESCRT complexes and Vps4 high-order oligomers,as well as the regulation of ESCRTs by ubiquitinated proteins and ubiquitination.We also suggest prospective studies based on these discussions.