Electron Beam Irradiation Dose Dependently Damages theBacillusSpore Coat and Spore Membrane

Abstract

<jats:p>Effective control of spore-forming bacilli begs suitable physical or chemical methods. While many spore inactivation techniques have been proven effective, electron beam (EB) irradiation has been frequently chosen to eradicate<jats:italic>Bacillus</jats:italic>spores. Despite its widespread use, there are limited data evaluating the effects of EB irradiation on<jats:italic>Bacillus</jats:italic>spores. To study this,<jats:italic>B. atrophaeus</jats:italic>spores were purified, suspended in sterile, distilled water, and irradiated with EB (up to 20 kGy). Irradiated spores were found (1) to contain structural damage as observed by electron microscopy, (2) to have spilled cytoplasmic contents as measured by spectroscopy, (3) to have reduced membrane integrity as determined by fluorescence cytometry, and (4) to have fragmented genomic DNA as measured by gel electrophoresis, all in a dose-dependent manner. Additionally, cytometry data reveal decreased spore size, increased surface alterations, and increased uptake of propidium iodide, with increasing EB dose, suggesting spore coat alterations with membrane damage, prior to loss of spore viability. The present study suggests that EB irradiation of spores in water results in substantial structural damage of the spore coat and inner membrane, and that, along with DNA fragmentation, results in dose-dependent spore inactivation.</jats:p>

Multiple and Variable NHEJ-Like Genes Are Involved in Resistance to DNA Damage in Streptomyces ambofaciens

“…Electronic beam irradiation (EBI) was shown to induce loss of viability of Bacillus spores by damaging spore coat, by altering membrane permeability or by DNA fragmentation (Fiester et al, 2012). High level energy beam such as those used in this work (2.2 MeV) is likely to trigger DSB as the most significant lesions in the spore embedded DNA.…”

Immunogenicity of an Electron Beam Inactivated Rhodococcus equi Vaccine in Neonatal Foals

“…Preservation of the cell wall integrity after eBeam irradiation has also been shown for Paracoccidioides brasiliensis [47], and membrane damage of Bacillus spp. spores was observed only at high doses of eBeam irradiation [45]. Although the evaluation of the ultrastructure in our study did not reveal changes in the cell wall indicative of perforation or destruction of the cell in any of the treatment groups, data from the fluorescence assay, coupled with the presence of more severe ultrastructural changes affecting the layered cell wall of heat-inactivated bacteria, indicate that the cell wall of heat-inactivated bacteria were more severely compromised relative to the other treatment groups.…”

Effect of gamma irradiation on Pseudomonas syringae pv. tomato DC3000 - short communication

“…These data verify the destruction of cells and provide clear evidence of the antibacterial activity of irradiation. A previous study suggested that e-beam irradiation increases the inactivation of bacteria through DNA fragmentation (Fiester et al 2012). To test this hypothesis, genomic DNA extracted from irradiated cells was measured to determine the effect of GI on the DNA integrity.…”