| Anthrax, as the first natural focus disease known by human being, is an acute, lethal anthropozoonosis caused by Bacillus anthracis. Spore of Bacillus anthracis interests both armies and terrorists with its strong pathogenicity, great fatality, easy cultivation and storage, resistance to adverse physical and chemical factors. Countries and armies all over the world have become more alert after the 9.11 attack. Advanced defense techniques and equipments are badly needed for the military and social safety.The usual way to deal with spores in epidemic focuses is burning and time-lasting saturation, which will severely contaminate the eco-environment. Recent cases like terrorism attacks happening in crowded places such as buildings and vehicles make it more difficulty to decontaminate. All these conditions require more reliable, more environment-friendly ways.This subject employed bioinformatics and microbial methods to evaluate the reliability and representativeness of Bacillus cereus ,Bacillus thuringiensis, Bacillus subtilis as candidate substitutions for Bacillus anthracis, then analyzed the effects and influential factors of chemicals on germinated spores.Methods and results are as follows:1. Bioinformatics methods were employed for comparative analysis of genomes, 16S rRNA andα/β-type SASP(including genes, primary structures, secondary structures and territory structures)of Bacillus anthracis, Bacillus thuringiensis, Bacillus cereus and Bacillus subtilis, then microbiological methods for spore resistance to heat, UV and available chlorine. Results show that highly conserved genomes,α/β-type SASP and close phylogenies among Bacillus anthracis, Bacillus thuringiensisi and Bacillus cereus, and similar resistance among Bacillus anthracis, Bacillus cereus and Bacillus subtilis.It indicates that all three spores can be used to replace anthracis spore on spore resistance research with only thuringiensis and cereus spores available on genes research.2. We used qualitative systematic review to screen nutrients germinants and reaction conditions, then monitored the germinating effects at variable concentrations, pH and temperatures .Results show that 75.7% and 83% spores germinated after 150 minutes exposed to inosine (10 Mm, 37℃,pH8.0) and L-alamine( 100Mm, 30℃,pH 8.5) respectively. The mixed solution of inosine and L-alamine didn't make a higher germination rate and that of AGFK (asparagine, glucose, fructose and potassium)was not more than 20%.3.Resistance of germinated spores to heat ( 85℃,15min ) and hydrogen peroxide(1.28M,10min) was measured with the suspension quantitative germicidal test, and the damage of hydrogen peroxide to genomic DNA was experimented as well. Results show that heat (85℃,15min)and hydrogen peroxide(1.28M,10min) killed 90.4% and 94.8% germinated spores ,respectively, with no ungerminated spores killed either. Ten minutes after exposing to hydrogen peroxide (1.28M), genes gerD and gabD of germinated spores were damaged tested by PCR, which indicated a declined resistance of germinated spore to toxic chemicals.4. Bacillus cereus is similar to Bacillus anthracis in both microscopic and macroscopic aspects thus can be a safe and available substitution for the latter. L-alamine and inosine are effective nutrient germinants under proper circumstances, which make them key measures to cause a rapid and sharp decline of spore resistance... |
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