Toxicity of sodium fluoride to Caenorhabditis elegans / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the toxic effect of sodium fluoride (NaF) on the nematode Caenorhabditis elegans (C. elegans).</p><p><b>METHODS</b>Adult C. elegans were exposed to different concentrations of NaF (0.038 mmol/L, 0.38 mmol/L, and 3.8 mmol/L) for 24 h. To assess the physiological effects of NaF, the brood size, life span, head thrashes, and body bend frequency were examined. Reactive oxygen species (ROS) and cell apoptosis were detected as parameters of biochemical response. The gene expressions were determined by real-time polymerase chain reaction (PCR) to assess the molecular-level response.</p><p><b>RESULTS</b>At the physiological level, the brood size of C. elegans exposed to 0.038 mmol/L, 0.38 mmol/L, and 3.8 mmol/L concentrations of NaF were reduced by 6%, 26%, and 28% respectively in comparison with the control group. The maximum life spans of C. elegans exposed to 0.038 mmol/L, 0.38 mmol/L, and 3.8 mmol/L concentrations of NaF were reduced by 3 days and 5 days, respectively. Head thrashes and body bend frequency both decreased with increasing concentrations of NaF. At the biochemical level, the production of ROS and the incidence of cell apoptosis increased with increasing concentrations of NaF (P < 0.05). At the molecular level, different concentrations of NaF exposure raised the expression of stress-related genes, such as hsp16.1, sod-3, ctl-2, dhs-28, gst-1, and cep-1.</p><p><b>CONCLUSION</b>NaF exposure could induce multiple biological toxicities to C. elegans in a concentration-dependent manner. These toxicities may be relevant to the oxidative stress induced by increased ROS production and accumulation in C. elegans.</p>

Rapid and quantitative detection of abrin using colloid gold immunochromatographic assay / 军事医学科学院院刊

Objective:To develop a rapid and quantitative detection method for abrin using colloid gold immunochromatographic assay. Methods:The rapid detection method was established with double-antibody sandwich assay. Quantification was realized by constructing a standard curve. The specificity and sensitivity of the method were tested, and its feasibility was evaluated by various abrin-added food samples. Results and Conclusion:This established method could accomplish qualitative and semi-quantitative detection in 15 minutes; the sensitivity was up to 30 ng/ml with a linear range from 30 ng/ml to 600 ng/ml. The recovery rate was 80%-110%, and the variation coefficient was less than 15%.The colloidal gold immunochromatographic assay is rapid, specific, sensitive,accurate and suitable for field detection.

Genetic Transformation of Phytoene Synthase Gene into Ginseng Callus Cells / 中国生物工程杂志

Phytoene synthase is a rate-limiting enzyme in the pathway of carotenoid biosynthesis.To aim at establishing a transformation of Ginseng callus cells, elevating the nutritive value through encouraging the composition of corresponding carotenoid,taking Ginseng callus cells as acceptor,psy gene were transformed into cells via Agrobacterium-mediated. The factors affecting genetict ransformation were also investigated seperately from concentrations of A.tumefaciens, age of Ginseng callus cells, infection time and co-culture time. PCR,PCR-Southern and RT-PCR analysis from the transferred gene plants proved that psy gene has been transferred into Ginseng callus cells and can be expressed. The content of ?-carotene was increased by an average of 26 times.A base of improving and raising the contents of carotenoid in the Ginseng callus cell was established.