BackgroundCranial radiation therapy for treating childhood malignancies in the central nervous system or accidental radiation exposure may result in neurological side effects in surviving adults. As tissue homeostasis is maintained by stem cells, understanding the effect of radiation on neural stem cells will provide clues for managing the neurological effects. Drosophila embryos were used as a model system whose sensitivity to irradiation-induced cell death changes from the sensitive to resistant stage during development.ObjectiveDrosophila embryos at the radiation-sensitive stage were irradiated at various doses and the radiation sensitivity was tested regarding the appearance of apoptotic cells in the embryos and the embryonic lethality. Cell fates of the neural stem cells called neuroblasts (NBs) and adult motor function after irradiation were also investigated.ResultIrradiation of Drosophila embryos at the radiation-sensitive stage resulted in a dose-dependent increase in the number of embryos containing apoptotic cells 75 min after treatment starting at 3 Gy. Embryonic lethality assayed by hatch rate was induced by 1 Gy irradiation, which did not induce cell death. Notably, no apoptosis was detected in NBs up to 2 h after irradiation at doses as high as 40 Gy. At 3 h after irradiation, as low as 3 Gy, the number of NBs marked by Dpn and Klu was decreased by an unidentified mechanism regardless of the cell death status of the embryo. Furthermore, embryonic irradiation at 3 Gy, but not 1 Gy, resulted in locomotor defects in surviving adults.ConclusionEmbryonic NBs survived irradiation at doses as high as 40 Gy, while cells in other parts of the embryos underwent apoptosis at doses higher than 3 Gy within 2 h after treatment. Three hours after exposure to a minimum dose of 3 Gy, the number of NBs marked by Dpn and Klu decreased, and the surviving adults exhibited defects in locomotor ability.

BackgroundBacterial ghosts (BGs) are empty cell envelopes commonly generated using Gram-negative bacteria; they represent a potential platform for efficient adjuvant and vaccine delivery systems. However, the efficient production of BGs from bacteria in a short period of time is challenging.ObjectiveThe purpose of this study was to investigate the possibility of producing BGs in the Gram-positive Bacillus subtilis using various chemicals, and the potential application of BGs as a novel immunomodulatory agent.ResultsIn this study, Bacillus subtilis ghosts (BSGs) were generated, for the first time to the best of our knowledge, using the minimum inhibitory concentration (MIC) of hydrochloric acid (HCl; 6.25 mg/mL), sulfuric acid (H2SO4; 3.125 mg/mL), and nitric acid (HNO3; 6.25 mg/mL). Among the BSGs generated using these chemicals, HCl-induced BSGs were completely DNA-free as confirmed by real-time polymerase chain reaction. Scanning electron microscopy showed the formation of transmembrane lysis tunnel structures in HCl-induced BSGs. Murine macrophages exposed to the HCl-induced BSGs at a concentration of 1 × 105 CFU/mL showed a cell viability of 97.8%. Additionally, HCl-induced BSGs upregulated the expression of pro-inflammatory cytokines including interleukin (IL)-1β, tumor necrosis factor alpha, and IL-6. Furthermore, we found differences in the protein expression profiles between intact live bacteria and BSGs using two-dimensional electrophoresis coupled with peptide mass fingerprinting/matrix-assisted laser desorption/ionization-time of flight mass spectrometry analysis.ConclusionThese data suggest that the HCl-induced BSGs may be potentially safe and effective candidates for inactivated bacterial vaccines and/or immunostimulants.

To investigate the effects of Panax ginseng (PG) on SH-SY5Y human neuroblastoma cells, we profiled gene expressions of both normal and PG-treated groups using cDNA microarray. We performed 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays to determine the effect on PG-induced cytotoxicity. The gene expression profiles in normal group were compared to PG-treated group using 24K human cDNA microarray. MTT assay showed that PG was not cytotoxic at the concentrations of 1–100 μg/mL in SH-SY5Y cells. Consequently, 210 genes exhibited differential expression levels between normal and PG-treated groups through cDNA microarray analysis, and it was found that 52 of the 210 genes were up-regulated while 146 of them were down-regulated by two-fold. PG may induce changes in the expression of genes in SH-SY5Y cells possibly relevant to signal transduction and cellular development. These results help to further understand the molecular framework of PG as a signal transduction inducer of neuronal cells.