Dose estimation with the calibration of dose-response curve of micronucleus in human peripheral lymphocytes induced by 50MeV proton beams

The purpose of this paper is to establish an easy and reliable biodosimeter protocol to evaluate the biological effects of proton beams. Human peripheral blood lymphocytes were irradiated using proton beams [LET: 34.6 keV micro m[-1]], and the chromosome aberrations induced were analyzed using cytokinesis-blocked [CB] micronucleus [MN] assay. To determine the efficiency of MN assay in estimating the doses received by 50MeV proton beams and to monitor predicted dose of victims in accidental exposure, here we have evaluated the performance of MN analysis in a simulated situation after exposure with proton beams. Peripheral lymphocytes were irradiated by 50MeV proton beams up to 6Gy and analyzed by Giemsa staining of CB MN assay. The detected MN was found to be a significant dose-effect curve in the manner of dose-dependent increase after exposure with proton beams in vitro. When plotting on a linear scale against radiation dose, the line of best fit was Y=0.004+[1.882x10[-2] +/- 9.701x10[-5]] D+[1.43x10[-3] +/- 1.571x10[-5]]D2. Our results show a trend towards increase of the number of MN with increasing dose. It was linear-quadratic and has a significant relationship between the frequencies of MN and dose [R2= 0.9996]. The number of MN in lymphocyte that was observed in control group is 5.202 +/- 0.04/cell. Hence, this simple protocol will be particularly useful for helping physicians to decide medical therapy for the initial treatment of victims with rapid and precise dose estimation after accidental radiation exposure. Also it has potential for use as a valuable biomarker to evaluate the biological effectiveness for cancer therapy with proton beams

YCF and YAP gene expressions in yeast cells after irradiation combined with mercury treatment

All aerobically growing organisms suffer from exposure to oxidative stress, caused by partially reduced forms of molecular oxygen, known as reactive oxygen species [ROS]. These are highly reactive and capable of damaging cellular constituents such as DNA, lipids and proteins. Consequently, cells from many different organisms have evolved mechanisms to protect their components against ROS. It is known to have some genes for resistance to heavy metals and ionizing radiation [IR]. Saccharomyces cerevisiae is an ideal model organism for deducing biological processes in human cells. In this work, cell viability and gene expression was investigated in yeasts treated with IR, HgCl[2], and IR combined with HgCl[2]. Cell viability was measured by colony forming unit [CFU] method in an YPD medium. Gene expression was analyzed by the Real-time PCR. The viability was lower at the higher dose. At a dose above a certain level, the viability came down to zero. The combined treatment decreased the viability, as well. Metal resistance genes were expressed in the cells treated with HgCl[2]. In a similar way, irradiation also triggered the expression of some radiation resistance genes. YCF and YAP genes were induced consecutively with the HgCl[2] concentration, and also with a higher total dose under a lower dose rate condition. These two genes were, however, expressed differently under the 0.2 mM HgCl[2] treatment condition. In the cells treated with 0.1-o.2 mM HgCl[2], the viability was higher than with any other concentrations. The results demonstrated that the higher dose induced more expression of oxidative stress resistance genes related to cell survival mechanism. Combined treatment of radiation with mercury chloride resulted in synergistic effects leading to a higher expression of the genes than treatment of a single stressor alone

Statistical analysis of main and interaction effects during the removal of BTEX mixtures in batch conditions using wastewater treatment plant sludge microbes

Biodegradation has proved to be a versatile technique to remediate benzene, toluene, ethyl benzene and xylene [BTEX] mixtures in contaminated soil and groundwater. In this study, a mixed microbial culture obtained from a wastewater treatment plant was used to degrade liquid phase BTEX, at initial concentrations varying between 15 to 75 mg/l. Experiments were conducted according to the 2k-1 fractional factorial design to identify the main and interaction effects of parameters and their influence on biodegradation of individual BTEX compounds in mixtures. The removal efficiencies of these compounds varied between 2 to 90% depending on the concentration of other compounds and also on their interaction effects. A statistical interpretation of the results was done based on the Fishers variance ratio [F] and probability [P] values. Though all the main effects were found significant [P < 0.05] at the 5% confidence level, the interactions between benzene and toluene and benzene and xylene concentrations were also found to be statistically significant and play a major role in affecting the total BTEX removal