Characterization of LysB4, an endolysin from the Bacillus cereus-infecting bacteriophage B4

<p>Abstract</p> <p>Background</p> <p><it>Bacillus cereus </it>is a foodborne pathogen that causes emetic or diarrheal types of food poisoning. The incidence of <it>B. cereus </it>food poisoning has been gradually increasing over the past few years, therefore, biocontrol agents effective against <it>B. cereus </it>need to be developed. Endolysins are phage-encoded bacterial peptidoglycan hydrolases and have received considerable attention as promising antibacterial agents.</p> <p>Results</p> <p>The endolysin from <it>B. cereus </it>phage B4, designated LysB4, was identified and characterized. <it>In silico </it>analysis revealed that this endolysin had the VanY domain at the N terminus as the catalytic domain, and the SH3_5 domain at the C terminus that appears to be the cell wall binding domain. Biochemical characterization of LysB4 enzymatic activity showed that it had optimal peptidoglycan hydrolase activity at pH 8.0-10.0 and 50°C. The lytic activity was dependent on divalent metal ions, especially Zn²⁺. The antimicrobial spectrum was relatively broad because LysB4 lysed Gram-positive bacteria such as <it>B. cereus, Bacillus subtilis </it>and <it>Listeria monocytogenes </it>and some Gram-negative bacteria when treated with EDTA. LC-MS analysis of the cell wall cleavage products showed that LysB4 was an <smcaps>L</smcaps>-alanoyl-<smcaps>D</smcaps>-glutamate endopeptidase, making LysB4 the first characterized endopeptidase of this type to target <it>B. cereus</it>.</p> <p>Conclusions</p> <p>LysB4 is believed to be the first reported <smcaps>L</smcaps>-alanoyl-<smcaps>D</smcaps>-glutamate endopeptidase from <it>B. cereus</it>-infecting bacteriophages. The properties of LysB4 showed that this endolysin has strong lytic activity against a broad range of pathogenic bacteria, which makes LysB4 a good candidate as a biocontrol agent against <it>B. cereus </it>and other pathogenic bacteria.</p

Directions for and prospects of the Environmental Health Study in Korean National Industrial Complexes (EHSNIC): A proposal for the third phase of the EHSNIC

The Environmental Health Study in the Korean National Industrial Complexes (EHSNIC) is a project that aims to monitor the exposure and health effects of environmental pollution among residents of national industrial complexes, as well as propose appropriate environmental health measures. Since its launch in 2003, this project has been initiated in eight national industrial complexes. Currently, it is necessary to review the accomplishments and limitations of the phases 1 and 2 of this project, and establish the direction of the upcoming the phase 3. Thus, the present study has developed principles and goals for the phase 3, considering the rationale and justification of the EHSNIC, and presented specific research contents accordingly. In the phase 3, it is important to improve the methods for exposure assessment and evaluation of health effects, in order to identify clearly the association between the pollutants released from industrial complexes and their health impacts, to develop and to reinforce communication strategies to promote participation of residents of communities near industrial complexes. Nonetheless, it is also important to maintain the basic goal of continuously monitoring the level of exposure to and health effects of environmental pollutants

Effects of mutation on the expression of SPI1-regulatory genes () and apparatus/effector genes () in

<p><b>Copyright information:</b></p><p>Taken from "Mlc regulation of pathogenicity island I gene expression via repression"</p><p></p><p>Nucleic Acids Research 2007;35(6):1822-1832.</p><p>Published online 28 Feb 2007</p><p>PMCID:PMC1874608.</p><p>© 2007 The Author(s)</p> Typhimurium, as analyzed by primer extension analysis. Total RNA was prepared from SL1344 (lane 1; wild type) and SR1304 (lane 2; mutant), which were grown to exponential growth phase in LB medium without shaking. Aliquots of 30 μg of total RNA were co-precipitated and annealed with end-labeled primers. Reactions were performed as described in the Materials and Methods section. The products were resolved on a 6% sequencing gel