p150 ADAR1 isoform involved in maintenance of HeLa cell proliferation

BACKGROUND: RNA-specific adenosine deaminase ADAR1 is ubiquitously expressed in a variety of mammalian cells and tissues. Although its physiological importance in non-nervous tissues has been confirmed by analysis of null mutation phenotypes, few endogenous editing substrates have been identified in numerous peripheral tissues and biological function of ADAR1 has not been fully understood. METHODS: A conditional site-specific, ribozyme-based gene knock-down strategy was utilized to study the function of full-length isoform of ADAR1 (p150 protein) in HeLa cell. Double-stable HeLa cell lines were developed by transfecting HeLa Tet-On cells with a pTRE-derived plasmid that can express a hammerhead ribozyme against mRNA of p150 ADAR1 isoform under induction condition. Semi-quantitative RT-PCR and Western blotting were performed to measure the expression of p150 in selected cell clones. Cell proliferation was evaluated by means of MTT assay and growth curve analysis. Cellular morphological changes were observed under light microscope. Flow Cytometry was used for cell cycle analysis. Growth rate of cell transplants in BALB/c nude mice was also investigated. RESULTS: Both HeLa cell proliferation in vitro and the growth rate of transplanted HeLa cell-derived tumors in nude mice in vivo were significantly inhibited due to reduced expression of ADAR1 p150. Additionally, cell cycle analysis showed that cell progression from G1 phase to S phase was retarded in the ADAR1 p150 suppressed cells. CONCLUSION: Our results suggest that normal expression and functioning of p150 ADAR1 is essential for the maintenance of proper cell growth. The mechanisms underlying ADAR1's action might include both editing of currently unknown double-stranded RNAs and interacting with other cellular dsRNA-related processes

Interaction of Mesoporous Silica Nanoparticles with Human Red Blood Cell Membranes: Size and Surface Effects

The interactions of mesoporous silica nanoparticles (MSNs) of different particle sizes and surface properties with human red blood cell (RBC) membranes were investigated by membrane filtration, flow cytometry, and various microscopic techniques. Small MCM-41-type MSNs (∼100 nm) were found to adsorb to the surface of RBCs without disturbing the membrane or morphology. In contrast, adsorption of large SBA-15-type MSNs (∼600 nm) to RBCs induced a strong local membrane deformation leading to spiculation of RBCs, internalization of the particles, and eventual hemolysis. In addition, the relationship between the degree of MSN surface functionalization and the degree of its interaction with RBC, as well as the effect of RBC−MSN interaction on cellular deformability, were investigated. The results presented here provide a better understanding of the mechanisms of RBC−MSN interaction and the hemolytic activity of MSNs and will assist in the rational design of hemocompatible MSNs for intravenous drug delivery and in vivo imaging

A Novel Replication-Competent Vaccinia Vector MVTT Is Superior to MVA for Inducing High Levels of Neutralizing Antibody via Mucosal Vaccination

Mucosal vaccination offers great advantage for inducing protective immune response to prevent viral transmission and dissemination. Here, we report our findings of a head-to-head comparison of two viral vectors modified vaccinia Ankara (MVA) and a novel replication-competent modified vaccinia Tian Tan (MVTT) for inducing neutralizing antibodies (Nabs) via intramuscular and mucosal vaccinations in mice. MVTT is an attenuated variant of the wild-type VTT, which was historically used as a smallpox vaccine for millions of Chinese people. The spike glycoprotein (S) of SARS-CoV was used as the test antigen after the S gene was constructed in the identical genomic location of two vectors to generate vaccine candidates MVTT-S and MVA-S. Using identical doses, MVTT-S induced lower levels (∼2-3-fold) of anti- SARS-CoV neutralizing antibodies (Nabs) than MVA-S through intramuscular inoculation. MVTT-S, however, was capable of inducing consistently 20-to-100-fold higher levels of Nabs than MVA-S when inoculated via either intranasal or intraoral routes. These levels of MVTT-S-induced Nab responses were substantially (∼10-fold) higher than that induced via the intramuscular route in the same experiments. Moreover, pre-exposure to the wild-type VTT via intranasal or intraoral route impaired the Nab response via the same routes of MVTT-S vaccination probably due to the pre-existing anti-VTT Nab response. The efficacy of intranasal or intraoral vaccination, however, was still 20-to-50-fold better than intramuscular inoculation despite the subcutaneous pre-exposure to wild-type VTT. Our data have implications for people who maintain low levels of anti-VTT Nabs after historical smallpox vaccination. MVTT is therefore an attractive live viral vector for mucosal vaccination

Study of some problems on the development and protection of fracture-karst water resources in North China

Water resources are in shortage in China, especially in northern China. As surface water often dries in spring and summer, fracture-karst water becomes an important source for supply. [[Karst in China can be divided into three types: karst in northern China, karst in southern China and karst in western China. Karst in northern China is not a typical karst but a fracture karst. The aquifers are networks of solution fractures, fissures and openings. Some wide solution fractures become strong runoff zones. The aquifer has a large coefficient of transmissibility and small storage capacity. It is strongly heterogeneous and anisotropic. Fracture-karst water flows at a high velocity and so the transport of contaminants is a advection-dominated problem. The amount of fracture-karst water depends on the condition of recharge. As the storage capacity is small, the fluctuation of water level in wells is greater than that in porous aquifer. [[According to the previous data, some authors suggested that the depths of wells in a fracture-karst aquifer should be less than 100∼300 m. In the Zibo area we found that some deep wells (at depths 500∼700 m) had also great pumping rates and the yields reached 3000∼5000 m3/d. It may be related to the palaeokarst in the geologic history. [[Fracture-karst water is vulnerable to contamination and the environment is fragile. Therefore, factories, plants, dumps and landfills should not be placed on the recharge areas of fracture-karst water. When making land planning, considerations should be given to protect cultivated land as well as groundwater resources. Compared with porous water both the velocity and the distance of plume movement in fracture-karst water are much larger. The curves of contaminant concentrations versus time in fracture-karst wells often fluctuate greatly, which are different from those in porous water wells. Pumping is one of the best methods for remediation. If the area of the groundwater basin is not large, we can renew contaminated water by pumping. If it is large o

Study of some problems on the development and protection of fracture-karst water resources in North China

Water resources are in shortage in China, especially in northern China. As surface water often dries in spring and summer, fracture-karst water becomes an important source for supply. [[Karst in China can be divided into three types: karst in northern China, karst in southern China and karst in western China. Karst in northern China is not a typical karst but a fracture karst. The aquifers are networks of solution fractures, fissures and openings. Some wide solution fractures become strong runoff zones. The aquifer has a large coefficient of transmissibility and small storage capacity. It is strongly heterogeneous and anisotropic. Fracture-karst water flows at a high velocity and so the transport of contaminants is a advection-dominated problem. The amount of fracture-karst water depends on the condition of recharge. As the storage capacity is small, the fluctuation of water level in wells is greater than that in porous aquifer. [[According to the previous data, some authors suggested that the depths of wells in a fracture-karst aquifer should be less than 100∼300 m. In the Zibo area we found that some deep wells (at depths 500∼700 m) had also great pumping rates and the yields reached 3000∼5000 m3/d. It may be related to the palaeokarst in the geologic history. [[Fracture-karst water is vulnerable to contamination and the environment is fragile. Therefore, factories, plants, dumps and landfills should not be placed on the recharge areas of fracture-karst water. When making land planning, considerations should be given to protect cultivated land as well as groundwater resources. Compared with porous water both the velocity and the distance of plume movement in fracture-karst water are much larger. The curves of contaminant concentrations versus time in fracture-karst wells often fluctuate greatly, which are different from those in porous water wells. Pumping is one of the best methods for remediation. If the area of the groundwater basin is not large, we can renew contaminated water by pumping. If it is large o